阅读说明：本技术 导体电缆和连接配对件间的电接触、电池单元连接系统及其制造方法 (Electrical contact between a conductor cable and a connection partner, battery cell connection system and method for producing the same ) 是由 M.亨勒 S.埃伯哈特 M.瓦格纳 O.达利诺 K.利贝尔特 A.贝里凯瓦苏 A.M.德 于 2021-03-25 设计创作，主要内容包括：一种具有在导体电缆的电导体和电连接配对件之间的电接触的装置,其中,导体嵌入扁平导体电缆的绝缘护套中的接触平面中,其中,至少在一个接触侧上在预定的接触部段中电导体被剥去绝缘护套,其中,导体的接触部段以接触侧从接触平面弯曲到超过绝缘护套,其中,导体的接触部段的接触侧放置在电连接配对件上,并且直接连接到电连接配对件。本发明还涉及一种用于车辆电池模块的电池单元连接系统,包括接触元件以及感测电缆。导线和/或接触元件的表面在彼此接触的区域中包括表面积增加特征。表面积增加特征改善了焊接工艺,因为可以实现更高的焊接力,并在焊接零件之间实现更多的材料转移。本发明还涉及制造电池单元连接系统的方法。(A device with electrical contact between an electrical conductor of a conductor cable and an electrical connection counterpart, wherein the conductor is embedded in a contact plane in an insulating sheath of a flat conductor cable, wherein the electrical conductor is stripped of the insulating sheath in a predetermined contact section at least on one contact side, wherein the contact section of the conductor is bent with the contact side from the contact plane beyond the insulating sheath, wherein the contact side of the contact section of the conductor is placed on the electrical connection counterpart and is directly connected to the electrical connection counterpart. The invention also relates to a battery cell connection system for a vehicle battery module, comprising a contact element and a sensing cable. The surfaces of the wires and/or contact elements include surface area increasing features in the areas where they contact each other. The surface area increasing feature improves the welding process because higher welding forces can be achieved and more material transfer between the welded parts is achieved. The invention also relates to a method of manufacturing a battery cell connection system.)

1. A device with electrical contact between an electrical conductor (3) of a conductor cable (1) and an electrical connection counterpart (2), the electrical conductor (3) of the conductor cable (1), in particular the electrical conductor (3) of a flexible flat conductor cable, the conductor (3) is embedded in an insulating sheath (4) of the conductor cable (1) in a contact plane (13), wherein the electrical conductor (3) is stripped of the insulating sheath (4) in a predetermined contact section (5) at least on one contact side (7), wherein the contact section (5) of the conductor is bent with a contact side (7) from the contact plane (13) beyond the insulating sheath (4), wherein a contact side (7) of the contact section (5) of the conductor (3) is placed on the electrical connection counterpart (2) and is directly connected to the electrical connection counterpart (2).

2. The device according to claim 1, wherein the contact section (5) of the conductor (3) is bent with its contact side (7) out of the contact plane (13) in a first direction (12) beyond the outside of the insulating sheath (4), wherein the contact side (7) of the contact section of the conductor (3) is placed on and directly connected to the electrical connection counterpart (2), and wherein the conductor cable (1) is bent in a second direction (11) in the region of the contact section (5), wherein the second direction (11) points in the opposite direction to the first direction (12).

3. The device according to one of the preceding claims, wherein the contact side (7) of the contact section (5) of the electrical conductor (3) is connected to the electrical connection counterpart (2) by a plurality of contact points (15, 16).

4. The device according to one of the preceding claims, wherein the contact section (5) of the electrical conductor (3) is divided into two partial sections (17, 18), and wherein at least one partial section (17, 18) of the electrical conductor (3) is placed with a contact side (7) on the electrical connection counterpart (2) and is connected to the connection counterpart (2).

5. The device according to one of the preceding claims, wherein the contact section (5) of the electrical conductor (3) is embedded in an insulating material (22), in particular in an electrically insulating potting material.

6. Device according to one of the preceding claims, wherein the connection counterpart (2) and the conductor (3) are formed of different electrically conductive materials.

7. The device according to claim 6, wherein the connection counterpart (2) is made of aluminum and the conductor (3) is made of copper.

8. Device according to one of the preceding claims, wherein the electrical connection counterpart (2) is a contact of an electrical terminal (26, 27, 28) of a battery (23, 24, 25), in particular a vehicle battery.

9. Device according to one of the preceding claims, wherein the electrical conductor (3) is connected to the electrical connection counterpart (2) by means of a welded connection, in particular a laser or ultrasonic welded connection.

10. The device according to one of claims 1 to 9, wherein the contact section is at least partially stamped into the electrical connection counterpart.

11. The device according to claim 10, wherein the interface between the contact section and the electrical connection counterpart is positioned below a surface of the connection counterpart immediately adjacent to the interface, in particular at most about 0.1 to 0.5mm, more in particular at most about 0.2 to 0.3mm below the surface.

12. The device of claim 10 or 11, wherein a surface of the contact section and a surface of the electrical connection counterpart comprise mating surface area increasing features at the interface.

13. Battery cell connection system for a vehicle battery module, in particular for an electric or hybrid vehicle, comprising an apparatus according to one of claims 1 to 12,

-wherein the electrical connection counterpart comprises a contact element (109, 111) for receiving an electrode of at least one battery cell,

-the conductor cable comprises a sensing cable (127, 129, 131, 133) comprising conducting wires (137a-e), the conducting wires (137a-e) electrically and mechanically connecting the battery cell monitoring unit (125) and the contact elements (109, 111),

the method is characterized in that:

the surfaces of the wires and/or the contact elements comprise surface area increasing features (155, 165, 175) in the areas where they contact each other.

14. A battery cell connection system for a vehicle battery module, in particular for an electric or hybrid vehicle, comprising

-a contact element (109, 111) for receiving an electrode of at least one battery cell,

-a sensing cable (127, 129, 131, 133) comprising conducting wires (137a-e), the conducting wires (137a-e) electrically and mechanically connecting a battery unit monitoring unit (125) and the contact elements (109, 111),

the method is characterized in that:

the surfaces of the wires and/or the contact elements comprise surface area increasing features (155, 165, 175) in the areas where they contact each other.

15. The battery cell connection system of claim 13 or 14, wherein the surface area increasing features (165, 175) comprise a plurality of bumps.

16. The battery cell connection system according to claim 15, wherein the projection (165) extends linearly, in particular parallel to a longer side of the contact area.

17. The battery cell connection system according to claim 15, wherein the bumps have a pyramidal shape (175), in particular a pointed pyramidal shape.

18. The battery cell connection system of claim 17, wherein the pyramid shape (175) has a rectangular, in particular square, base shape and a side angle of about 30 ° to 60 °, in particular 45 °.

19. The battery cell connection system according to one of claims 15 to 18, wherein the projections (155, 165, 175) have a height of at most 0.5mm, in particular at most 0.2mm, more in particular at most 0.1 mm.

20. The battery cell connection system according to one of claims 15 to 19, wherein the tips of directly adjacent projections (165, 175) are at a distance of at most 5mm, in particular at most 0.2mm, from each other.

21. The battery cell connection system according to one of claims 13 to 20, wherein the lead (153, 163, 173) and the contact element (145) are welded together, in particular ultrasonically welded together.

22. The battery cell connection system according to claim 21, wherein the contact element (145) and the lead (153, 163, 173) are made of different materials, in particular aluminum and copper, respectively.

23. The battery cell connection system according to claim 22, comprising a plurality of contact elements arranged in two rows (105, 107) allowing for a series electrical connection of battery cells, and wherein one of the contact elements opposite each other is electrically and mechanically connected with a conductor of the sensing cable (127, 129, 131, 133).

24. Battery cell connection system according to claim 23, wherein the sensing cable (127, 129, 131, 133) comprises a plurality of parallel wires (137a-f), in particular flat wires, embedded in an electrical insulation (139), wherein each wire connected to a contact element is electrically and mechanically connected to another of said contact elements, and wherein the electrical insulation is removed in each contact area.

25. Method for manufacturing a device according to one of the preceding claims, wherein an electrical conductor of a conductor cable, in particular of a flexible flat conductor cable, is embedded in an insulating sheath of the conductor cable in a contact plane, wherein the conductor is stripped of the insulating sheath in a predetermined contact section at least on one contact side, comprising the steps of:

a) bending the contact section of the conductor out of the contact plane to at least one outer side of the insulating sheath,

b) placing the conductor cable on the connection counterpart, in particular after the conductor is bent out of the contact plane,

c) placing the contact side of the contact section of the conductor on the electrical connection counterpart and then

d) Connecting the contact side of the contact section directly to the electrical connection counterpart.

26. Method according to claim 25, wherein the contact side of the electrical conductor is welded to the electrical connection counterpart, in particular by means of laser welding or ultrasonic welding.

27. The method of claim 26, comprising the steps of: prior to soldering, the contact side of the electrical conductor is pressed down against the electrical connection counterpart using a pressure wave formed by inducing a phase change in the pressure generating material, in particular a phase change from a liquid or solid phase to a gas phase and/or an explosion.

28. The method of claim 27, wherein the forming of the pressure wave comprises the steps of: the pressure generating material is hit with one or more laser pulses, in particular with the same laser as the welding.

29. The method according to claim 27 or 28, wherein the pressure generating material is provided on the contact section (5) or above the contact section (5) in the form of droplets or a cladding.

30. Method according to one of claims 25 to 29, wherein the contact section of the conductor is bent with the contact side protruding from the contact plane in a first direction beyond the outside of the insulating sheath, wherein the conductor cable is subsequently moved in a direction towards the connection counterpart and the contact side of the contact section of the conductor is placed on the electrical connection counterpart and is directly connected to the electrical connection counterpart.

31. The method according to claim 30, wherein the conductor cable is bent in a second direction in the region of the contact section before placing the conductor on the connection counterpart and before soldering, wherein the second direction points in a direction opposite to the first direction.

32. Method according to one of claims 25 to 31, wherein the contact section of the conductor is divided into a first and a second partial section and at least a first partial section is bent away from the contact plane, wherein the first partial section is placed on the connection counterpart and is connected with the connection counterpart with a contact side.

33. Method according to one of claims 25 to 32, wherein steps a) and c) are carried out simultaneously by embossing the contact section (5) in the electrical connection counterpart (2).

34. The method according to claim 33, wherein embossing is achieved using a stamping press (51) having a flat or structured surface.

35. Method according to one of claims 25 to 34 for obtaining a battery cell connection system according to claim 13, wherein the surface area increasing features are achieved by using a punch (181) or a scraping tool or by laser structuring.

36. Method for attaching a sensing cable to a contact element of a battery cell connection system according to one of claims 14 to 24, comprising the steps of: removing insulation from the sensing wire to form an exposed area of the wire and forming a surface area increasing feature on the exposed area of the wire, wherein the surface area increasing feature is achieved with a punch (181) or a scraping tool or by laser structuring.

37. Method for attaching a sensing cable to a contact element of a battery cell connection system according to one of claims 14 to 24, wherein the surface area increasing feature is achieved by using a punch (181) or a scratching tool or by laser structuring.

38. Method according to claim 36 or 37, wherein a punch (181) or a scratching tool or a laser structuring is applied on the side of the wire and/or the contact element on which the electrical and mechanical connection is to be established.

39. Method for attaching a sensing cable to a contact element according to one of the claims 36 to 38, wherein the electrical and mechanical connection is achieved by welding, in particular by laser or ultrasonic welding.

Technical Field

The invention relates to a configuration of an electrical contact between an electrical conductor of a conductor cable, in particular of a flexible flat conductor cable, and an electrical connection counterpart, and to a method for producing a device with an electrical contact between an electrical conductor of a conductor cable, in particular of a flexible flat conductor cable, and an electrical contact.

The invention also relates to a battery cell connection system for a vehicle battery module, in particular for an electric or hybrid vehicle, comprising a contact element for receiving an electrode of at least one battery cell and a sensing cable comprising wires electrically and mechanically connecting a battery cell monitoring unit and the contact element. The invention also relates to a method for attaching a sensing cable to a contact element of a battery cell connection system as described above.

Background

From EP 0699353B 1 an electrical connection device is known, wherein a flexible circuit arrangement is connected to a planar substrate, wherein the flexible circuit arrangement comprises a flexible flat strip of circuit arrangement, wherein at least one end of the circuit arrangement in the longitudinal direction is bent back onto itself to form an elastic spring, such that the upper side of the part bent back is located adjacent to the surface of the part of the strip which is not bent back. The conductors are not insulated on the surface side, avoiding the surface from bending backwards, and can therefore be elastically pressed against the conductive tracks of the planar substrate. In another embodiment, the flexible flat conductor cable includes a notch in the direction of the contact, the notch being placed over the contact.

Disclosure of Invention

A first object of the invention is to provide an improved device with electrical contact between an electrical conductor of a conductor cable, in particular of a flexible flat conductor cable, and a connection counterpart, and to provide an improved method for establishing electrical contact between an electrical connection counterpart and an electrical conductor of a conductor cable, in particular of a flexible flat conductor cable.

Battery cell connection systems are known in the art, for example from DE102014219178a1, and are used in battery modules of electric or hybrid vehicles to connect a plurality of battery cells to one another. In order to be able to monitor the state of the battery cells, it is necessary to monitor parameters such as battery temperature, capacity or load state. For this purpose, the monitoring unit is electrically connected to each battery cell by a cable via the contact elements of the battery cell connection system. The monitoring unit may also be used to balance the cells. In this case, it may be referred to as a monitoring and balancing unit.

In order to ensure a sufficiently long service life of the battery module, it is important to achieve an electrically and mechanically stable connection even in everyday use, during which vibrations, shocks, etc. also exert mechanical stresses on the connection. The connection between the cable and the battery cell connection system is achieved by ultrasonic welding.

Therefore, the car manufacturers place stringent requirements on the reliability of the connection. A 90 peel tension test, as is known in the art, is performed and the connection needs to support a force of at least 7N before the connection breaks. During the 90 ° peel tension test, the previously connected cable was bent to 90 ° to be perpendicular to the contact surface. The force at the disconnection is then measured. Machine performance characteristic value: cmk should be greater than 1.67.

A second object of the invention is therefore to improve the mechanical reliability and therefore the electrical condition and the electrical connection, thus improving the monitoring possibilities of the battery.

The first object is achieved by a device having an electrical contact between an electrical conductor of a conductor cable, in particular of a flexible flat conductor cable, and an electrical connection counterpart. The conductor is embedded in the insulating sheath of the conductor cable in the contact plane. The conductor is stripped of the insulating sheath at a predetermined contact section at least on one contact side of the electrical conductor. The contact section of the conductor is bent with its contact side out of the contact plane, in particular beyond the insulating sheath. The contact side of the contact section of the conductor is placed on the electrical connection counterpart and establishes a direct electrical contact with the electrical connection counterpart. Furthermore, the contact side of the electrical conductor is connected to the electrical connection counterpart in the region of the contact section.

The connection can be made by welding, in particular by laser welding or ultrasonic welding.

The connection partners can be, for example, electrical conductor strips, electrically conductive plates or any other type of contact elements.

In the region of the contact section, the insulating sheath of the conductor cable is not bent in the direction of the electrical connection counterpart. The conductor cable can be configured, for example, to be planar in the region of the contact section and to transition in a planar manner into the adjacent region of the conductor cable in the longitudinal direction before and after the contact section. This prevents further mechanical stresses on the conductor cable and the other conductors of the conductor cable in the region of the contact section. Since in the present exemplary embodiment the electrical conductor is only configured to be bent in the direction of the electrical connection counterpart, the processing effort, in particular the mechanical processing effort, for establishing the electrical contact is reduced. In addition, since the conductor cable does not need to be deflected in the direction of the electrical connection counterpart, it is achieved in this way that a plurality of electrical contacts of adjacent conductors are offset with respect to one another in the longitudinal direction of the conductor cable. The conductor cable can be configured to be flat and smooth in the region of the contact section. Thus, an overall planar support of the conductor cable on the connection counterpart can be obtained.

In one embodiment, the contact section of the electrical conductor is bent such that the contact side protrudes from said contact plane in the first direction beyond the outer side of the insulating sheath. The contact side of the contact section of the electrical conductor is then placed on the electrical connection counterpart and directly connected to the electrical connection counterpart. The conductor cable is bent in the region of the contact section in a second direction, i.e. the insulating sheath of the conductor cable is just outside the contact section, so that the second direction points in the opposite direction to the first direction. Due to the deflection of the conductor cable in the direction opposite to the bending of the electrical conductor, a preload is exerted on the electrical conductor. The constriction section of the electrical conductor is therefore preloaded in the direction of the connection counterpart and can be pressed onto the electrical connection counterpart with a higher pressing force. Thus, an electrical connection between the electrical conductor and the electrical connection counterpart can be established with higher quality and in a simpler way. In particular, the electrical conductor itself does not have to be pressed onto the electrical connection counterpart with a mechanical tool in the region of the contact section. For example, in the case of a laser or ultrasonic welded connection, the electrical and mechanical connection between the electrical connection counterpart and the electrical conductor can additionally be improved in this way. Furthermore, in the present embodiment, during assembly, there is more free space in the region of the contact section of the conductor. The connection between the conductor and the connection partner can thus be established more easily.

In a further embodiment, the bending of the contact section can be realized such that no stretching of the electrical conductor occurs in the bending region. Whereby a reduction in cross section can be prevented. Thus, mechanical damage of the contact section can be prevented.

In a further embodiment, the contact side of the contact section is connected to the electrical connection partner by a plurality of contact points. In this way, the mechanical connection between the electrical conductor and the electrical connection counterpart is improved. Furthermore, the electrical connection between the electrical conductor and the electrical connection counterpart is likewise improved. For example, the contact points can be produced by means of laser welding. In the present embodiment, the contact point may be made by a spirally formed laser weld. However, other shapes and/or methods, such as ultrasonic welding, may be used to achieve the contact points.

In another embodiment, the contact section of the electrical conductor is divided into two partial sections perpendicular to the longitudinal direction of the conductor cable. In this embodiment, at least one partial section of the electrical conductor is placed with a contact side on the electrical connection counterpart and is mechanically and electrically connected with the electrical connection counterpart.

In a further embodiment, at least a part of the contact section of the electrical conductor is embedded in an insulating material, in particular in an electrically insulating potting material. In this way both an electrical insulation of the contact section of the electrical conductor and a mechanical protection of the contact section of the electrical conductor are achieved.

In another embodiment, the electrical connection counterpart and the electrical conductor are formed from different electrically conductive materials, wherein in particular the electrical connection counterpart may be formed from aluminum and the electrical conductor from copper. With the described device according to the invention, a good electrical contact between the conductor and the connection partner can be achieved even when different electrically conductive materials are used, in particular when copper and aluminum are used. Laser welding or ultrasonic welding connections are particularly suitable for establishing a good electrical connection and a sufficient mechanical connection between aluminum and copper.

In one embodiment, the electrical connection counterpart is a contact of an electrical terminal of a battery, in particular of a vehicle battery. The battery may for example be part of an arrangement of a plurality of batteries, wherein the batteries are voltage measured, for example using electrical conductors.

In another embodiment, the contact section can be at least partially stamped into the connection partner. The advantage of embossing is that the two parts can be joined during production without the need for an additional clamping step to hold the two parts together. Therefore, a more efficient manufacturing process can be used, and at the same time, a sufficiently high mechanical strength can be achieved.

In another embodiment, the interface between the contact section and the electrical connection counterpart may be positioned below a surface of the connection counterpart immediately adjacent to the interface, in particular at most about 0.1 to 0.5mm, more in particular at most about 0.2 to 0.3mm below the surface. This further improves the mechanical strength.

In another embodiment, a surface of the contact section and a surface of the electrical connection counterpart may comprise mating surface area increasing features at the interface. Using an imprint stamp with a structured surface, for example with a plurality of regularly arranged pyramidal protrusions on its surface, the pattern is transferred onto the contact section and extends to the surface side of the contact section that is engaged with the connection counterpart. This may further improve the attachment force before the final joining step, e.g. using welding.

The second object of the invention is achieved by a battery cell connection system for a vehicle battery module, in particular for an electric or hybrid vehicle, according to claim 13, comprising a device as described above-wherein the electrical connection counterpart comprises a contact element for receiving an electrode of at least one battery cell, the conductor cable, in particular the flexible flat conductor cable, comprises a sensing cable comprising wires electrically connecting and mechanically connecting the battery monitoring unit and the contact element, characterized in that the wires and/or the surface of the contact element comprise surface area increasing features in the area of contact with each other. By increasing the surface area compared to a smooth surface, the mechanical contact force can be increased due to the larger interaction surface. According to the present embodiment, the first and second objects of the present invention are achieved.

The second object of the invention is also achieved by a battery cell connection system for a vehicle battery module, in particular for a battery module of an electric or hybrid vehicle, according to claim 14. The battery cell connection system includes a contact element for receiving an electrode of at least one battery cell, and a sensing cable including a lead electrically and mechanically connected with the battery monitoring unit and the contact element. Characterized in that the surfaces of the wires and/or the contact elements comprise surface area increasing features in the areas where they are in contact with each other. By increasing the surface area compared to a smooth surface, the mechanical contact force can be increased due to the larger interaction surface.

According to a variant of the invention, the surface area increasing feature may comprise a plurality of bumps. By forming bumps on the surface, the contact surface area can be easily increased.

According to a variant of the invention, the bumps may extend linearly, in particular parallel to the longer sides of the contact areas. Such a pattern is easy to implement.

According to a variant of the invention, the bumps may have a pyramidal shape, in particular a pointed pyramidal shape. Such a pattern increases the surface area even further and provides contact sides in different directions.

According to a variant of the invention, the pyramidal shape may have a rectangular, in particular square, base shape, and a lateral angle of about 30 ° to 60 °, in particular 45 °. According to a variant of the invention, the bumps have a height of at most 0.5mm, in particular at most 0.2mm, more in particular at most 0.1 mm. According to a variant of the invention, the tips of directly adjacent projections can be at most 5mm, in particular at most 0.2mm, from one another. These dimensions may improve contact force compared to a flat smooth surface.

According to a variant of the invention, the wire and the contact element can be welded together, in particular by ultrasonic welding. The surface area increasing feature allows for higher and more stable welding forces, as higher material transfer can occur between the welded components.

According to a variant of the invention, the contact element and the conductor can be made of different materials, in particular of aluminum and copper, respectively. The invention even allows combining two different materials and obtaining a satisfactory connection. When using a material with a thin electrically isolating oxide layer on the surface, it is preferred to achieve the surface area increasing feature at least on this material.

According to a variant of the invention, the battery cell connection system may have a plurality of contact elements arranged in two rows, allowing a series electrical connection of the battery cells, and wherein one of the contact elements opposite to each other is electrically and mechanically connected with the conductor of the sensing cable.

According to a variant of the invention, the sensing cable may comprise a plurality of parallel wires, in particular flat wires, embedded in an electrical insulation, wherein each wire connected to a contact element is electrically and mechanically connected to another one of the contact elements, and wherein the electrical insulation is removed in each contact area.

Furthermore, according to a first object of the present invention, according to claim 25, a method for manufacturing a device having an electrical contact between an electrical conductor of a conductor cable, in particular of a flexible flat conductor cable, and an electrical connection counterpart is provided. For this purpose, a conductor cable, in particular a flexible flat conductor cable, is provided, which comprises at least one, in particular a plurality of, electrical conductors which are embedded in a contact plane in an insulating sheath of the conductor cable. At least one electrical conductor is stripped of the insulating sheath at least at predetermined contact sections on one contact side. For example, the electrical conductor in the contact section can also be stripped of the insulating sheath on all sides. The method comprises the following steps: a) bending the contact side of the contact section of the electrical conductor out of the contact plane to at least one outer side of the insulating sheath, step b) placing, in particular after bending the conductor out of the contact plane, a conductor cable, in particular a flexible flat conductor cable, on the connection counterpart, step c) placing the contact side of the contact section of the electrical conductor on the electrical connection counterpart, and then step d) connecting the contact side of the contact section of the conductor to the electrical connection counterpart. In one embodiment in step d), the contact side of the electrical conductor is soldered to the electrical connection counterpart.

In this method, it is advantageous if the insulating sheath is not bent in the region of the contact section in the direction of the connection partner. This leaves more space for the connection of the conductor to the connection partner. The insulating sheath of the conductor cable may be arranged in the region of the contact section in a planar manner with respect to the upper side of the electrical connection counterpart or may have a curvature remote from the electrical connection counterpart. Both embodiments allow a simple and reliable electrical contact between the electrical conductor and the electrical connection counterpart.

In one embodiment, the contact side of the electrical conductor is welded to the electrical connection counterpart by means of a laser. For example, one or more contact points or solder joints may be formed between the electrical conductor and the electrical connection counterpart. In particular, the laser may form a laser seam, which is, for example, spiral-shaped and forms a contact point. Alternatively, ultrasonic welding may be used.

According to an embodiment, the method may comprise the steps of: prior to soldering, the contact side of the electrical conductor is pressed down towards the electrical connection counterpart using a pressure wave formed by inducing a phase change in the pressure generating material, in particular from a liquid or solid phase to a gas phase, and/or an explosion. The formation of such a pressure wave for pushing the contact section onto the electrical connection counterpart has the following advantages: the manufacturing process can be realized without clamping or at least with less clamping, since at most only clamping is required to realize the first welding point. The pressure generating material may be the same material as used for making the connection, e.g. a welding material or glue. In a variant, it may be a combustible material, for example CH₃NO₂。

According to an embodiment, the pressure wave forming step may comprise the steps of: the pressure generating material is hit with one or more laser pulses, in particular with the same laser as the welding. Thus, the same laser used to effect the weld can be used to generate the pressure wave. The first spray may be used to ignite droplets of combustible material, or one or more pulses may be used to evaporate small droplets of phase change material, such as solder or glue. The next subsequent pulse may then be used to effect soldering between the contact section and the electrical connection counterpart.

According to embodiments, the pressure generating material may be provided on or over the contact section in the form of droplets or a cladding. By arranging the pressure generating material in the vicinity of the contact section, the depression effect after the generation of the pressure wave can be optimized.

Before placing the electrical conductor on the electrical connection counterpart and before soldering the conductor to the connection counterpart, in one embodiment the conductor cable is bent in a second direction in the region of the contact section, i.e. the insulating sheath of the conductor cable is just outside the contact section, the second direction being opposite to the first direction in which the electrical connection counterpart is bent. By forming the bend in the conductor cable in a direction opposite to the bending direction of the electrical conductor, a preload is created on the electrical conductor, which makes electrical contact between the electrical conductor and the electrical connection counterpart easy and better. This means that it is no longer necessary to use at least partially or even completely a special compacting system.

In another embodiment, the contact section of the electrical conductor is divided into a first and a second partial section perpendicular to the longitudinal direction. At least one first partial section of the electrical conductor is bent out of the contact plane. According to selected embodiments, it is also possible to first bend the electrical conductor out of the contact plane and subsequently to divide the electrical conductor into two partial sections in the region of the contact section. At least one first partial section is placed on the electrical connection counterpart and soldered to the electrical connection counterpart by means of the contact side. Depending on the selected embodiment, both partial sections can be placed on the electrical connection counterpart and connected to the electrical connection counterpart in an electrically conductive manner.

The division of the electrical conductor into two partial sections in the region of the contact section offers the following advantages: the actual conductor cable may extend in a planar manner, the insulation-stripped conductor may be configured as a spring element, substantially without stretching, and therefore, without reducing the cross-section, a deflection of the electrical conductor from the contact plane is easier to achieve and may be achieved with less mechanical stress exerted on the electrical conductor. In this way even thick conductors can be bent out of the contact plane with little pressure. Even with thick insulating sheaths with corresponding bends in the partial sections, the partial sections can be guided out of the insulating material of the conductor cable with little mechanical deformation by means of the partial sections. This reduces the mechanical stress on the electrical conductor in the region of the contact section, in particular in the case of thicker insulating sheaths. In this way, mechanical stresses and deformations of the electrical conductor are reduced, thereby improving the electrical contact in terms of long service life. In particular, the mechanical connection of the electrical conductor can be protected in this way and is less damaged when it is bent out of the contact plane. This also improves the long-term stability of the electrical contact. In addition, the influence on the cross section of the electrical conductor is small in the region of the contact section. In this way, parameters for the connection, in particular for soldering the electrical conductor to the electrical connection counterpart, can be set more precisely. This also improves the quality of the electrical and mechanical contact between the electrical conductor and the electrical connection counterpart. Furthermore, the long-term stability of the electrical contact between the electrical conductor and the electrical connection partner is thus likewise improved. This is particularly advantageous for applications in the field of vehicles, since vehicles are subjected to mechanical vibration stresses during handling and thermal loads, in particular high-temperature fluctuations. The quality of the mechanical and electrical connection between the electrical conductor and the electrical connection counterpart of the battery is particularly important when establishing contact with the electrical contacts of the vehicle battery.

According to an embodiment, steps a) and c) may be simultaneously achieved by embossing the contact section in the electrical connection counterpart. Thus, a conductor cable with a contact section is placed on the electrical connection counterpart and then the contact section is bent towards and stamped into the surface of the electrical connection counterpart using a punch. Thus, in one step, the two parts can be held together, thereby eliminating the need for additional clamping of the two parts prior to welding.

According to a variant, a punch with a flat or structured surface can be used. Using a structured surface, for example a plurality of pyramid-shaped surfaces arranged regularly, a surface pattern can be obtained on the surface side of the contact section that actually faces the surface electrical connection counterpart, which surface pattern will be embossed in the same way to form a mating pattern on the surface of the counterpart. A higher surface area may improve the coupling force between the two parts.

The second object of the present invention, which is combined with the first object, is achieved by a method as described above, with which a battery cell connection system according to the second object of the present invention can be obtained, wherein the surface area increasing features are realized using a punch or a scraping tool or by laser structuring. Thus, at the moment the electrical connection between the two parts is achieved, the electrical contact is improved.

The second object of the invention is also achieved by a method for attaching a sensing cable to a contact element of a battery cell monitoring system according to the above embodiment according to claim 35. The method comprises the step of using a punch or a scraping tool or by laser structuring to achieve the surface area increasing features. This method allows to obtain an improved joining force compared to a smooth-surfaced joint. At the same time, the structuring of the surface may damage the thin oxide layer on the surface of the wires and/or the contact elements. Thus, at the moment the electrical connection between the two parts is achieved, the electrical contact is improved.

According to a variant of the invention, a punch or a scratching tool or a laser structuring is applied on the side of the conductor and/or the contact element on which the electrical and mechanical connection is to be established.

According to a variant of the invention, the electrical and mechanical connection can be achieved by welding, in particular ultrasonic welding. The surface area increasing feature allows for higher and more stable welding forces, as higher material transfer can occur between the welded components.

According to further variants, any embodiment and variants thereof relating to the first inventive subject matter may be combined with any one or more variants relating to the second inventive subject matter.

Drawings

The invention may be understood by reference to the following description taken in conjunction with the accompanying drawings, in which reference numerals identify the features of the invention.

Fig. 1 shows a schematic perspective view of a flexible flat conductor cable on an electrical contact;

fig. 2 shows a schematic partial cross-sectional view of the flexible flat conductor cable and the electrical contact according to fig. 1;

fig. 3 shows a longitudinal sectional view of the flexible flat conductor cable of fig. 1;

FIG. 4 illustrates an embodiment of a flexible flat conductor cable having bent out electrical conductors;

fig. 5 shows a top view of the flexible flat conductor cable according to fig. 4, wherein the electrical conductors are placed on the electrical connection counterpart;

fig. 6 shows a partial section of a top view of a flexible flat conductor cable with electrical conductors connected to an electrical connection counterpart by contact or solder joints;

fig. 7 shows a schematic view of another embodiment of a flexible flat conductor cable in which electrical conductors are connected to an electrical connection counterpart in two partial sections;

fig. 8 shows a perspective view with two partial sections of the flexible flat conductor cable, with two partial sections of the electrical conductors leading out of the insulating sheath, in a view looking at the underside of the flexible flat conductor cable;

fig. 9 shows a perspective view of a flexible flat conductor cable with two partial sections of electrical conductors placed on an electrical connection counterpart;

fig. 10 shows a perspective view of two partial sections with the arrangement of fig. 7;

fig. 11 shows a partial cross-sectional view of the flexible flat conductor cable and the electrical contact according to fig. 7;

fig. 12 shows the arrangement of fig. 11, wherein a partial section of the electrical conductor of the flexible flat conductor cable is embedded in the insulating material;

fig. 13 shows a schematic view of a battery with its electrical terminals in contact with the conductors of a flexible flat conductor cable.

Fig. 14a to 14e show schematic views of a method of bending a contact section onto an electrical connection counterpart according to an embodiment of the invention.

Fig. 15a to 15c show a schematic representation of a method of stamping a contact section into an electrical connection counterpart according to an embodiment of the invention.

Fig. 16 shows a battery cell connection system for a vehicle battery module according to the present invention.

Figures 17a to 17c schematically show a variation of the surface area increasing feature according to the present invention.

Fig. 18 shows a punch having a pointed pyramidal shape to form surface area increasing features in a wire.

Fig. 19 shows the peel force according to four embodiments of the present invention compared to a comparative example having a smooth surface.

Detailed Description

Fig. 1 to 15 relate to an embodiment related to a first object of the present invention.

Fig. 1 shows a schematic view of a conductor cable 1 placed on an electrical connection counterpart 2. In the present and following embodiments, a flexible flat conductor cable is used, but the present invention is not limited thereto, and any type of conductor cable in which at least one electrical conductor is embedded in an insulating sheath may be used.

The flexible flat conductor cable 1 comprises a plurality of electrical conductors 3, 10 embedded in an insulating sheath 4. In the embodiment shown, the flexible flat conductor cable 1 comprises nine electrical conductors 3, 10, which are embedded in an insulating sheath 4. In the contact section 5, the electrical conductor 3 is stripped of its insulating jacket 4. This means that the electrical conductor 3 does not have the material of the insulating sheath 4 on all sides in the region of the contact section 5. In addition, the electrical conductor 3 is placed with one contact side of its contact section on the electrical connection counterpart 2.

Fig. 2 shows the arrangement of fig. 1 in a schematic partial cross-sectional view, which extends along an electrical conductor 3. It can clearly be seen that the electrical conductor 3 already has no insulating sheath 4 in the contact section 5. Furthermore, the electrical conductor 3 is placed on the contact section 5 and one contact side is placed on the upper side of the electrical connection counterpart 2. The remaining electrical conductors 10 of the flexible flat conductor cable 1 are completely embedded in the insulating sheath. Depending on the embodiment selected, it is also possible to strip the further electrical conductor 10 from the insulating material of the insulating sheath in the contact section and to place it with one contact side on the electrical connection counterpart 2. The stripped contact sections of the further electrical conductors 10 can be arranged at the same height as the flexible flat conductor cable 1 or in a different longitudinal section thereof, viewed in the longitudinal direction of the flexible flat conductor cable 1.

Fig. 3 shows a schematic cross-section of the arrangement of fig. 1. The insulating sheath 4 comprises a recess 9 in the region of the contact section 5.

As can be seen from the illustration in fig. 3, the flexible flat conductor cable 1 is placed on the side of the contact section 5 with the insulating sheath 4 on the upper surface side 8 of the electrical connection counterpart 2 of the electrical contact. However, in the region of the contact section 5, the flexible flat conductor cable 1 is bent upwards from the upper surface side 8 of the electrical contact 2 in the second direction 11. In addition, the electrical conductor 3 is bent in the region of the contact section 5 from the contact plane 13 of the insulating sheath 4 in the first direction 12 downward in the direction of the electrical connection counterpart 2. A contact plane 13 is usually formed in the center of the insulating sheath 4, wherein the electrical conductors 3, 10 of the flexible flat conductor cable are arranged in the insulating sheath 4. The bending of the conductor 3 in the direction towards the connection counterpart 2 causes the contact side 7 of the electrical conductor 3 to rest firmly on the upper side 8 of the electrical contact 2. In addition, the cable section 14 bent upward in the second direction 11 can be used to apply a pretensioning force to the contact section 5 of the electrical conductor 3 in the direction of the electrical connection counterpart 2. In addition, this results in the conductor 3 being more easily bent in the direction of the connection counterpart 2 without having to deform the conductor 3.

According to selected embodiments, the flexible flat conductor cable 1 can also be placed on the connection partner 2 in a planar manner in the region of the contact section 5. However, in the present embodiment, the conductor 3 is deformed, in particular stretched, to allow flexing in a direction towards the connection counterpart 2.

Fig. 4 shows a further exemplary embodiment of a flexible flat conductor cable 1 in a perspective view, the flexible flat conductor cable 1 having an electrical conductor 3 which is bent out of an insulating sheath 4 in a first direction 12. Meanwhile, in the contact section 5, the cable section 14 has a shape curved in the second direction 11 arranged opposite to the first direction 12 with respect to the remaining portion of the flexible flat conductor cable 1 extending in a planar manner.

Fig. 5 shows the flexible flat conductor cable 1 of fig. 4 placed on the electrical connection counterpart 2. Here, the contact section 5 of the electrical conductor 3 is placed on the upper side 8 of the electrical connection counterpart 2. In the present embodiment, the flexible flat conductor cable 1 includes six electrical conductors 3, 10, which are shown in phantom. The electrical conductor 3 is not yet mechanically connected to the electrical connection counterpart 2 by its contact section 5, but is merely placed on the upper side 8 of the electrical connection counterpart 2. In a subsequent method step, the contact section 5 of the electrical conductor 3 is connected to the upper side 8 of the electrical connection counterpart 2. For this purpose, for example, a welded connection, an adhesive connection or a soldered connection can be used. In particular, a laser welded connection can be used as the welded connection. The welding of the contact section 5 of the electrical conductor 3 to the upper side 8 of the electrical contact 2 is done by a laser beam. According to selected embodiments, one or more weld points 15 may be used, as shown in FIG. 6. As an alternative to laser welding, ultrasonic welding may also be used.

Fig. 6 shows in an enlarged illustration a detail of the arrangement of fig. 5, wherein the electrical conductor 3 is soldered to the electrical connection counterpart 2 using two solder joints 15, 16. Depending on the embodiment chosen, only one welding point may be used or also more than two welding points may be used. Alternatively, instead of circular welds, elongated, rectangular or zigzag weld connections may be chosen. For example, the welded connection can be established by means of a laser beam which is guided in a spiral from a center point of the welding point to an edge region of the welding point.

Fig. 7 shows a perspective view of a further device with electrical contact between an electrical conductor 3 of a flexible flat conductor cable 1 and an electrical connection counterpart 2. The illustration in fig. 7 is a schematic view of the flexible flat conductor cable 1 seen from above, the flexible flat conductor cable 1 being shown placed on the electrical connection counterpart 2. The recess 9 is introduced into the insulating sheath 4 of the flexible flat conductor cable 1 so that the contact section 5 of the electrical conductor 3 is stripped from the insulating material of the insulating sheath 4. In addition, the contact section 5 of the electrical conductor 3 is divided into a first partial section 17 and a second partial section 18. The first and second partial sections 17, 18 are guided out of the contact plane of the insulating sheath 4 downward relative to the flexible flat conductor cable 1 and are placed on the upper side 8 of the electrical connection partner 2. In addition, each partial section 17, 18 is electrically and mechanically connected to the electrical connection counterpart 2 by means of two corresponding solder joints 15, 16. The welding points 15, 16 may be produced, for example, by laser welding.

Fig. 8 shows the flexible flat conductor cable 1 of fig. 7 before being placed on the electrical connection counterpart 2. In this case, the partial sections 17, 18 of the electrical conductor 3 bent out of the insulating sheath 4 of the flexible flat conductor cable 1 can be easily identified. The partial sections 17, 18 are divided into a first section 19 and a second section 20, respectively. The first section 19 extends from the contact plane 13 of the insulating sheath 4 and is inclined at a predetermined angle with respect to the contact plane 13. The first section 19 transitions via a bend 21 into the second section 20. The second section 20 has a small inclination with respect to the contact plane 13 and can be arranged, for example, parallel to the plane of the flexible flat conductor cable 1. The first and second partial sections 17, 18 may be shaped in the same shape, such that the first sections 19 each have the same angle with respect to the plane of the flexible flat conductor cable 1 and the second sections 20 are arranged parallel to each other. Such a shape of the partial sections 17, 18 can simplify and improve the realization of the electrical contact between the electrical conductor 3 and the electrical connection counterpart 2.

Due to the shape of the partial sections 17, 18, the second sections 20 of the partial sections 17, 18 have a relatively large contact surface with the upper side 8 of the electrical contact 2 when the flexible flat conductor cable 1 is placed on the electrical connection counterpart 2. The second section 20 of the partial sections 17, 18 is therefore in large-area contact with the electrical connection partner 2. Thus, a large contact surface is provided. In addition, there are large surfaces for forming the connection between the connection partner 2 and the partial sections 17, 18.

Fig. 9 shows the flexible flat conductor cable 1 of fig. 8, which is placed on the electrical connection counterpart 2 such that the partial sections 17, 18 rest with the second section 20 on the upper side 8 of the electrical connection counterpart 2.

Fig. 10 shows the arrangement of fig. 9 after the partial sections 17, 18 have been soldered to the electrical connection partner 2 with the solder points 15, respectively.

Fig. 11 shows a schematic partial cross-sectional view of the arrangement of fig. 10, wherein the formation of the first and second sections 19, 20 of the partial sections 17, 18 is clearly visible. In the embodiment of fig. 11, two welding points 15, 16 are formed in the second section 20 of the partial sections 17, 18 and connect the partial sections 17, 18 to the electrical connection counterpart 2.

Fig. 12 shows a schematic partial cross-section of another embodiment of fig. 7. In the present exemplary embodiment, the first partial section 17 and the second partial section 18 are embedded in an insulating material 22. The insulating material 22 may be formed, for example, of an electrically insulating potting material, such as a plastic material. For example, the partial sections 17, 18 of the stripped insulation jacket 4 can be covered at least partially, in particular completely, by the insulation material 22. A safe and reliable electrical insulation of the partial sections 17, 18 is thereby achieved.

In a similar manner, the contact section 5 of the embodiment of fig. 1 to 6 may also be covered by an insulating material, in particular by an electrically insulating potting material.

Depending on the embodiment chosen, the electrical connection counterpart 2 and the electrical conductor 3 may be formed of different materials. For example, the electrical connection counterpart 2 may be made of aluminum. In addition, the electric conductor 3 may be formed of copper.

Fig. 13 shows in a schematic view an arrangement of a battery system with a plurality of batteries 23, 24, 25, each having an electrical terminal, some of the terminals 26, 27, 28 being schematically shown as rectangles. In addition, the flexible flat conductor cable 1 passes through the batteries 23, 24, 25. The flexible flat conductor cable 1 includes an electrical conductor 3, another electrical conductor 10, and an additional electrical conductor 29. The electrical conductors 3, 10, 29 are only schematically shown in partial sections, but the electrical conductors 3, 10, 29 are formed along the entire flexible flat conductor cable 1. In the embodiment shown, electrical conductor 3 is connected in an electrically conductive manner to a first terminal 26 of a first battery 23, another electrical conductor 10 is connected to a second terminal 27 of a second battery 24, and an additional electrical conductor 29 is connected to a third terminal 28 of a third battery 25, according to one of the embodiments described previously in fig. 1 to 12. For example, an arrangement of batteries is provided in a vehicle. The electrical terminals 26, 27, 28 of the battery represent electrical contacts. Depending on the embodiment chosen, only one battery may be provided with an electrical terminal connected to the conductors of the flexible flat conductor cable. The electrical contacts of the electrical terminals of the cells may be used to detect the voltage of the cells to balance them and/or the temperature of the cells. The battery has two terminals, which are not shown in this schematic.

Fig. 14a to 14e show another embodiment according to the present invention. Features having the same reference numerals as have been used in the description of the figures above will not be described in detail but are labelled.

Fig. 14a schematically shows a side cross-sectional view of a conductor cable, here in an exemplary form of a flexible flat conductor cable 1 with its insulating sheath 4 positioned on an electrical connection counterpart 2. The electrical conductor 3 is located in the contact plane 13 over its entire length. The contact section 5 has not yet been bent towards the surface 8 of the electrical connection counterpart 2. On the surface side 33 opposite the contact side 7, drops 31 of welding material or glue of explosive material or combustible material are positioned. Instead of a liquid material, it is also possible to use a suitable solid material, for example in the form of an explosive coating, which is arranged on the surface side 33 opposite the contact side 7.

Fig. 14b shows a laser pulse 35 emitted by a pulsed laser 37, impinging on the droplet 31.

Depending on the material used, the droplets 31 will immediately evaporate, burn or explode due to energy transfer. For this reason, a single laser pulse may be sufficient. In some applications, multiple pulses may be required.

After the phase transition, a pressure wave 39 is formed, which pressure wave 39 expands rapidly and presses the contact side 7 of the contact section 5 down against the surface 8 of the electrical connection counterpart 2. This is shown in fig. 14 c.

Subsequently, as shown in fig. 14d, while the contact section 5 is still depressed by the pressure wave 39, the laser 37 emits a further laser pulse 41 and impinges on the contact section 5 to weld it to the electrical connection counterpart 2 in the welding region 42.

Fig. 14e shows the final result. The contact section 5 is bent out of the contact plane 13 and is electrically and mechanically connected to the electrical connection counterpart 2. By pressing down the contact section 5 at the moment of interaction with the laser, a high quality weld 43 can be obtained.

Fig. 15a to 15c show another embodiment according to the invention. Features having the same reference numerals as have been used in the description of the figures above will not be described in detail but are labelled.

Fig. 15a schematically shows a side cross-sectional view of a conductor cable, here in an exemplary form of a flexible flat conductor cable 1 with its insulating sheath 4 positioned on an electrical connection counterpart 2. The electrical conductor 3 is located in the contact plane 13 over its entire length. The contact section 5 has not yet been bent towards the surface 8 of the electrical connection counterpart 2. The punch 51 is located directly above the contact section 5. The stamping surface 53 may be a flat surface with or without chamfered edges.

A variation of the embodiment is shown in the enlarged region 55. Here, the stamping surface 57 has a structured surface 59, for example a plurality of pyramid-shaped portions 61 arranged regularly on the stamping surface 57.

Fig. 15b shows the result after the punch 51 has moved downwards and pushed against the contact section 5 and the surface 8 of the electrical connection counterpart 2. Under the pressure of the punch 51, at least a portion 63 of the contact section 5 has been bent and impressed into a surface 65 of the electrical connection counterpart 2. The height 67 of the interface plane 69 of the stamp is 0.1 to 0.5mm, preferably 0.2 to 0.4mm, compared to the surface 8 abutting the embossed area 71.

The enlarged region 73 shows the interface 75 when using a punch 51 with a structured surface 59 as shown in fig. 15 a. Here, the contact section 5 and the electrical connection counterpart 2 have mating surface area increasing features 77 at the interface 75.

The advantage of embossing is that the two parts are positioned relative to each other without the need for additional clamping means, thereby simplifying the manufacturing process.

Subsequently, as shown in fig. 15c, the contact section 5 is soldered to the electrical connection counterpart 2 using a laser 79. Similar to the embodiments described above, one or more solder joints 81 may be implemented in the stamped area 71. Alternatively, ultrasonic welding may be used.

Thus, in the present embodiment, the bending and pacing (pacing) of the contact side on and in the surface 8 of the electrical connection counterpart 2 is achieved in one step.

Fig. 16 shows a battery cell connection system 100 for a battery module related to the second object of the present invention.

Such a battery cell connection system 100 is used in an electric or hybrid vehicle. It receives battery cells connected in parallel and in series to provide energy to the electric motor of the vehicle.

The battery cell connection system 100 comprises a support 103, typically made of plastic, on which support 103 a plurality of contact elements 109 and 111, typically made of aluminum, in two rows 105, 107 are mounted, for example using a snap-fit connection. The contact elements 109, 111 correspond to the electrical connection counterpart 2 of the above-described embodiment.

In the present embodiment, each contact element 109 and each contact element 111 comprises two contact element sections 109a, 109b and 111a, 111b, respectively. The two contact element sections 109a, 109b are electrically connected to each other. The contact element sections 111a, 111b are also electrically connected to each other.

In use, the positive and negative poles of the battery cell are positioned on opposite contact sections. Thus, one battery cell is on the contact element sections 109a, 111a and one battery cell is on the contact element sections 109b, 111 b. Thus, the battery cells are arranged in parallel. In a variation, fewer or more than two battery cells may be arranged in parallel. The battery cells are typically welded to the contact element sections to ensure a reliable electrical and mechanical connection.

In row 105, adjacent contact elements 113 are electrically isolated from contact elements 109 by isolation elements 115, which are typically integrally formed with the support. In the opposite row, adjacent contact elements 117 are electrically connected to contact element 111. Thus, the battery cells mounted on contact members 113 and 117 will be mounted in series with respect to the battery cells mounted on contact members 109 and 111. A parallel arrangement of pairs of cells connected in series with adjacent pairs of cells is achieved across rows 105 and 107. Thus, the pair of electrically connected contact elements is separated from the following pair of electrically connected elements by the spacer element 115. In this embodiment, only contact elements 109 in row 105 and contact elements 149 in row 107 are not electrically connected to adjacent contact elements.

The cell connection system 100 is connected to an adjacent cell connection system or motor via bus bars 119 and 121.

The battery cell connection system 100 also includes a Printed Circuit Board (PCB)123 having a battery cell monitoring unit 125. A monitoring unit 125 on the PCB 123 is electrically connected to at least some of the contact elements 109, 111, 113, 115 to monitor parameters of the battery cell, such as temperature, capacitance, e.g. for balancing the capacitance or the state of charge thereof. The connections are made using sensing cables, referred to herein as flexible flat cables 127, 129, 131 and 133, also referred to as flexible flat conductor cables in the above embodiments.

As can be seen in enlarged view 135, flexible flat cable 133 includes a plurality, here six, of parallel conductive wires 137a-f, here copper wires, which are separated from one another by electrical insulation 139, which in this embodiment is embedded in extruded PVC. Three of the wires (137c, 137d and 137e) are electrically and mechanically connected to one and only one contact element, here contact elements 145, 147 and 149. Furthermore, it can be seen from fig. 1 that only one wire is connected to each pair of opposing contact elements. Here, lead wire 137d and contact element 147, while the opposing contact element in row 105 is not connected to flexible flat cable 127 to monitor the installation of the battery cells. As for the opposing contact elements 109a and 111a, both of these elements are connected to their corresponding flexible flat cables 129 and 131.

The flexible flat cable 133 has an exposed area 141 in which the conductive wires 143 corresponding to the conductive wires 137c are not provided with an electrical insulation. Wire 143 is typically bonded to contact element 145 by ultrasonic bonding. For ultrasonic welding, as shown in fig. 1, the opposite side from where contact with the contact element 145 is made also needs to be free of electrical insulation 139, since the ultrasonic generator used for welding needs to be positioned on the wire. Typically, the surface to which the sonotrode is applied carries a visible imprint of the contact surface of the sonotrode.

According to the present invention, exposed regions 141 facing contact elements 145 include surface area increasing features such as bumps. In this context, a surface area increasing feature refers to a surface having a larger area than the smooth surface of a copper wire, which is obtained after removal of the electrical insulation 139, for example using a CO2 laser, and subsequent cleaning, for example mechanical cleaning using a metal and/or plastic brush (e.g. a round brush).

Fig. 17a to 17c show three different variations of the surface area increasing feature on exposed areas 141 of wire 143 in accordance with the present invention. The surface area increasing feature is on the side of the wire that will be in contact with contact element 145 as shown in fig. 16.

Fig. 17a shows the surface of the exposed area 151 of the wire 153 after the application of the scraping tool. The scratches 155 are preferably provided on the entire surface of the exposed region, and increase the surface area compared to a smooth surface.

Fig. 17b shows the surface of the exposed regions 161 of the wire 163 after application of a punch resulting in the formation of patterned surface area increasing features in the form of linear bumps 165 extending along the longer sides of the exposed regions 161. In another variation, the linear protrusion 165 may extend or be inclined along the short side. In the present embodiment, all the line-type protrusions 165 have the same shape. In variants, they may also be different, for example higher towards the edges. The linear bumps 165 have a height of at most 0.5mm, in particular at most 0.2mm, more in particular at most 0.1 mm. Furthermore, the tips of directly adjacent projections are at a distance of at most 5mm, in particular at most 0.2mm, from one another.

Fig. 17c shows the surface of the exposed areas 171 of the wires 173 after application of the punch 181 as shown in fig. 18, which application of the punch results in the formation of patterned surface area increasing features in the form of an array of pyramids 175 across the exposed areas 171. In the present embodiment, pyramid 175 is a pointed pyramid having a base shape of substantially rectangular, in particular substantially square, and having a side face angle of about 30 ° to 60 °, in particular 45 °. The pyramids 175 have a height of at most 0.5mm, in particular at most 0.2mm, more in particular at most 0.1 mm. Furthermore, the tips of the pyramids which are directly adjacent are at a distance of at most 5mm, in particular at most 0.2mm, from one another.

As shown in fig. 18, the punch 181 includes an array of regularly arranged pyramids 183.

Instead of imprinting the surface area increasing features into the surface of the conductive lines 163 or 173, a laser patterning process may also be used.

The invention also relates to a method for attaching a sensing cable to a contact element of a battery cell connection system as described above, and comprising the steps of: the electrical insulation 139 is removed from the flexible flat cables 127 to 133 to form exposed areas 141, 151, 161, 171 and the exposed areas are cleaned. This step is followed by a step of forming surface area increasing features using a punch or a scraping tool or by laser structuring to obtain one of the structures shown in fig. 17a, 17b or 17 c. Subsequently, the electrical and mechanical connection between the exposed areas 141, 151, 161, 171 of the wires 143, 153, 163, 173 is realized by soldering, in particular ultrasonic or laser soldering.

According to a variant, the shapes as shown in fig. 17a to 17c can also or alternatively be provided on the surface of the contact element 145.

Fig. 19 shows the results obtained after the 90 ° peel tension test described above, which satisfies Cmk > 1.67. It shows the individual measured values and the mean value.

For all samples, the same materials aluminum and copper were used as contact elements, respectively, and the same sonication process was applied.

Sample 191 corresponds to a comparative sample having a smooth surface. It can be seen that the peel tension test is satisfactory because the average level of 8.625N is higher than the desired 7N, see the horizontal dashed line. One of the test results was less than 7N.

Sample 193 corresponds to the surface area increasing features of the pyramidal shape of the cusps as shown in fig. 17 c. They are obtained by using a punch as shown in fig. 18. The pyramidal peaks on the wire show a square base in the directions 0 ° and 90 °, on average, with a distance between the peaks of 0.4mm, a height of 0.2mm and a flank angle of 45 °. When all measurements were above 7N, an average peel force of 13.154N was obtained.

Sample 195 corresponds to the surface area increasing feature in the form of linear bumps, with a distance between the apexes of 0.2mm, a height of 0.1mm, and a side angle of 45 ° as shown in fig. 17 b. When all measurements were above 7N, an average peel force of 9.482N was obtained.

Sample 197 corresponded to the surface area increasing features of the pyramidal shape of the cusps shown in fig. 17 c. They are obtained by using a punch as shown in fig. 18. The pyramidal peaks on the wire show a square base in the directions 0 ° and 90 °, on average, with a distance between the peaks of 0.2mm, a height of 0.1mm and a flank angle of 45 °. When all measurements were above 7N, an average peel force of 15.56N was obtained.

Sample 199 corresponds to a surface area increasing feature in the form of a scratch. All measurements were above 7N and the average peel force obtained was 12.598N.

All samples according to the invention have a higher peel force compared to wires with smooth surfaces. Sample 197 gave the best results, showing an improvement of about 80% compared to the control sample.

Various embodiments of the present invention have been described. However, it should be understood that various modifications and enhancements may be made without departing from the claims below. In particular, further embodiments according to the invention are achieved by combining embodiments relating to the first object of the invention with embodiments according to the second object of the invention.

List of reference numerals

1-conductor cable, here a flexible flat conductor cable

2 Electrical connection partner

3 electric conductor

4 insulating sheath

5 contact section

7 contact side

8 upper side of electric contact

9 recesses in the insulating sheath

10 another electrical conductor

11 second direction

12 first direction

13 plane of contact

14 cable section

15 first welding point

16 second welding point

17 first partial section

18 second partial section

19 first section

20 second section

21 bending part

22 insulating material

23 first battery

24 second battery

25 third battery

26 first terminal

27 second terminal

28 third terminal

29 additional electrical conductor

31 liquid droplet

33 surface side

35 laser pulses

37 laser

39 pressure wave

41 Another laser pulse

42 welding zone

43 welding

51 stamping press

53 punch surface

55 region of enlargement

57 stamping surface

59 structured surface

61 pyramid shape

63 contact part of the section 5

65 electrically connecting the stamping surfaces of the counterparts 2

67 height of imprint

69 interfacial plane

71 embossed area

73 enlarged area

75 interface

77 surface area increasing feature

79 laser

81 welding

100 cell connection system

103 support piece

105 rows of

107 second row

109 contact element

109a contact element section

109b contact element section

111 contact element

111a contact element section

111b contact element section

113 adjacent contact element

115 isolation element

117 adjacent contact elements

119 bus bar

121 bus bar

123 Printed Circuit Board (PCB)

125 cell monitoring unit

127 flexible flat cable

129 flexible flat cable

131 flexible flat cable

133 flexible flat cable

135 enlarged view

137a-f conducting wire

139 electrical insulation

141 exposed region

143 exposed regions of the conductive lines

145 contact element

147 contact element

149 contact element

151 exposed region

153 conducting wire

155 surface scratches as surface area increasing features

161 exposed region

163 conducting wire

165 wire bumps as surface area increasing features

171 exposed region

173 lead wire

175 pointed pyramid as surface area increasing feature

181 punch with pointed pyramid

191 comparative example

193-punched large pyramid

195 punched line type lug

197 stamped small pyramid

199 scratch surface area enhancement feature