阅读说明：本技术 通过使用涡电流来检查电池单体中的裂纹的方法以及检查装置 (Method for inspecting cracks in battery cell by using eddy current and inspection apparatus ) 是由 金奭镇 具尚贤 具滋训 李政勋 于 2020-03-25 设计创作，主要内容包括：本发明涉及一种用于通过使用涡电流来检测电池单体中的裂纹的装置,该装置包括：检查单元,该检查单元包括第一传感器和第二传感器,该第一传感器用于感应出涡电流,该第二传感器用于感测由第一传感器感应出的涡电流的信号,其中,在电池单体被驱动的同时,该检查单元通过涡电流来进行检查；转移单元,该转移单元用于将多个电池单体从引入电池单体的点到取出电池单体的点顺序地转移；和控制单元,该控制单元电连接到检查单元并且接收、评估和控制由检查单元感测到的涡电流信号。本发明的用于检测电池单体中的裂纹的装置能够通过非破坏性方法来检测在电极、电极接线片和焊接单元上产生的裂纹的存在和位置。(The present invention relates to an apparatus for detecting cracks in a battery cell by using eddy current, the apparatus comprising: an inspection unit including a first sensor for inducing an eddy current and a second sensor for sensing a signal of the eddy current induced by the first sensor, wherein the inspection unit performs an inspection by the eddy current while the battery cell is driven; a transfer unit for sequentially transferring the plurality of battery cells from a point of introducing the battery cells to a point of taking out the battery cells; and a control unit electrically connected to the inspection unit and receiving, evaluating and controlling the eddy current signal sensed by the inspection unit. The apparatus for detecting cracks in a battery cell of the present invention can detect the presence and location of cracks generated on an electrode, an electrode tab, and a welding unit through a non-destructive method.)

1. An apparatus for detecting cracks in a battery cell using eddy currents, the apparatus comprising:

an inspection unit configured to include: a first sensor for inducing eddy currents; and a second sensor for sensing an eddy current signal induced by the first sensor, and the inspection unit performs inspection using the eddy current while the battery cell moves;

a transfer unit configured to sequentially transfer a plurality of battery cells from a point of inputting the battery cells to a point of taking out the battery cells; and

a controller configured to be electrically connected to the inspection unit and to receive, evaluate and control the eddy current signal sensed by the inspection unit.

2. The apparatus of claim 1, wherein the cracks of the inside of the battery cell are cracks generated on the electrode, the electrode tab, and the welding part.

3. The apparatus of claim 1, wherein the inspection unit is designed to move the first and second sensors to a position to be inspected, and to perform inspection by eddy current in a state in which the first and second sensors are fixed.

4. The apparatus of claim 3, wherein the checking unit comprises:

a first position adjustment member configured to be coupled to the first sensor on one side and to a third position adjustment member on another side by a position fixing bolt;

a second position adjustment member configured to be coupled to the second sensor on one side and to be coupled to a third position adjustment member on the other side by a position fixing bolt;

a third position adjustment member configured to be coupled to the first and second position adjustment members, respectively, on one side and to be coupled to a fourth position adjustment member by a position fixing bolt on the other side; and

a fourth position adjustment member coupled to the third position adjustment member by the position fixing bolt,

wherein portions of the first position adjustment member and the second position adjustment member that are respectively coupled to the third position adjustment member are spaced apart at predetermined intervals on the same extension line,

wherein the third position adjustment member has a slide groove having a predetermined length for adjusting the positions of the first and second position adjustment members, and the first and second position adjustment members are movable along the slide groove, and

wherein the fourth position adjustment member has a slide groove having a predetermined length for adjusting a position of the third position adjustment member, and the third position adjustment member is movable along the slide groove.

5. The apparatus of claim 1, wherein the first sensor and the second sensor each comprise a coil.

6. The apparatus of claim 5, wherein the coil has a diameter of 0.5mm to 10 mm.

7. The apparatus of claim 1, wherein the transfer unit comprises:

a transfer die configured to extend from an input point of the battery cell to an exit point of the battery cell; and

a transfer device configured to transfer the battery cell.

8. The apparatus of claim 7, wherein the transfer unit has a plurality of unit movement intervals, and

wherein the transfer device reciprocates at one or more cell movement sections.

9. The apparatus according to claim 8, wherein the transfer mold includes a pocket in which the battery cell is disposed between one cell moving section and its adjacent cell moving section, and

wherein a receiving groove is formed, the receiving groove being recessed into the recessed seat according to the shape of the battery cell.

10. The apparatus of claim 7, wherein the transfer device comprises:

a lifting unit configured to lift the battery cell from the transfer mold; and

a driving unit configured to be coupled with the lifting unit so as to be movable and allow the lifting unit to reciprocate in a horizontal direction.

11. The apparatus of claim 10, wherein the lifting unit includes a hole for adsorbing a battery cell, and

wherein vacuum is applied through the adsorption holes to adsorb the battery cells.

12. The apparatus of claim 10, wherein the lifting unit is a cylinder reciprocated up and down by oil pressure or air pressure.

13. The apparatus according to claim 1, wherein the battery cell travels at a constant speed while the inspection unit performs the eddy current inspection.

14. The apparatus of claim 1, wherein a traveling speed of the battery cell in the inspection area is controlled to be different from traveling speeds of other areas.

15. The apparatus of claim 1, wherein the eddy current signal is a voltage.

16. The apparatus of claim 1, further comprising an optical sensor configured to transmit start and end time points of eddy current generation and detection to the first and second sensors,

wherein the optical sensor detects both ends of an electrode lead, transmits the detected ends to the first sensor and the second sensor, and

wherein the eddy current check is started by the detection signal at the first end and the eddy current check is ended by the detection signal at the second end.

Technical Field

The present application claims priority benefit based on korean patent application No. 10-2019-0044954 filed on 17.4.2019, and the entire contents of which are incorporated herein by reference.

The present invention relates to a method and apparatus for inspecting cracks inside a lithium secondary battery, and more particularly, to a method and apparatus for non-destructively detecting electrode cracks, tab cracks, and welding cracks using eddy current.

Background

As the price of energy increases due to exhaustion of fossil fuels and concern for environmental pollution increases, the need for environmentally friendly alternative energy sources becomes an indispensable factor for future life. In particular, as technology develops and the demand for mobile devices increases, the demand for secondary batteries as an energy source is also rapidly increasing.

In general, in terms of the shape of a battery, there is a high demand for a prismatic secondary battery and a pouch-type secondary battery that can be applied to products having a small thickness, such as mobile phones. In terms of materials, there is a high demand for lithium secondary batteries (such as lithium ion batteries and lithium ion polymer batteries) having high energy density, high discharge voltage, and high output stability.

Secondary batteries are classified according to the structure of a cathode, the structure of an anode, and the structure of an electrode assembly having a structure of a separator interposed between the cathode and the anode. Some examples of which include: a jelly-roll type (wound type) electrode assembly in which a long sheet type positive electrode and negative electrode are wound with a separator interposed therebetween; a stacking and folding type electrode assembly having a structure in which: winding unit cells such as bicells or full cells stacked with predetermined units of positive and negative electrodes stacked by separators; and so on.

In addition, the secondary battery is manufactured by: in a state where the electrode assembly is accommodated in the battery container, an electrolyte, which is a liquid electrolyte, is injected, and the battery container is sealed.

During the manufacture of the above-described electrodes or during the assembly of the electrode assembly, cracks may occur on the electrodes, the tabs, and the welded parts due to the difference in elongation between the coated portions and the uncoated portions, physical external forces caused by welding, and the like, and such cracks may cause low voltage defects.

There is a problem in that, in the case of stacking the folding-type battery cells, assembly defects occurring during the folding process cannot be easily found by visual inspection because cracks are inside the folded cells due to the characteristics of the stacking folding process, and there is no method of nondestructively detecting cracks in the sealed battery cells after the sealing is completed.

Accordingly, there is a need to develop a technique for a method and apparatus for non-destructively detecting cracks in battery cells.

Disclosure of Invention

[ problem ] to provide a method for producing a semiconductor device

The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide an apparatus and method for non-destructively detecting cracks in a sealed lithium secondary battery.

[ technical solution ] A method for producing a semiconductor device

In order to solve the above problems, the present invention provides an apparatus for detecting cracks in a battery cell using eddy current, the apparatus including:

an inspection unit, the inspection unit comprising: a first sensor for inducing eddy currents; and a second sensor for sensing an eddy current signal induced by the first sensor, and the inspection unit performs inspection by the eddy current while the battery cell is moving;

a transfer unit configured to sequentially transfer the plurality of battery cells from a point at which the battery cells are input to a point at which the battery cells are taken out; and

a controller configured to be electrically connected to the inspection unit and to receive, evaluate and control the eddy current signal sensed by the inspection unit.

In the present invention, the cracks in the battery cell may mean cracks generated on the electrode, the electrode tab, and the welding part.

In an embodiment of the present invention, the inspection unit may be designed to move the first and second sensors to a position to be inspected, and the inspection unit may perform the inspection by eddy current in a state in which the first and second sensors are fixed.

In an embodiment of the present invention, the inspection unit may include:

a first position adjustment member configured to be coupled to the first sensor on one side and to be coupled to a third position adjustment member by a position fixing bolt on the other side;

a second position adjustment member configured to be coupled to the second sensor on one side and to be coupled to a third position adjustment member on the other side by a position fixing bolt;

a third position adjustment member configured to be coupled to the first and second position adjustment members, respectively, on one side, and to be coupled to a fourth position adjustment member by a position fixing bolt on the other side; and

a fourth position adjustment member coupled to the third position adjustment member by a position fixing bolt.

Here, portions of the first position adjustment member and the second position adjustment member, which are respectively coupled to the third position adjustment member, may be spaced apart at predetermined intervals on the same extension line.

Further, the third position adjustment member may have a slide groove having a predetermined length for adjusting the positions of the first and second position adjustment members, and the first and second position adjustment members may be movable along the slide groove.

Further, the fourth position regulating member may have a slide groove having a predetermined length for regulating the position of the third position regulating member, and the third position regulating member may be movable along the slide groove.

In an embodiment of the invention, the first sensor and the second sensor may each comprise a coil.

Here, the diameter of the coil may be 0.5mm to 10 mm.

In an embodiment of the present invention, the transfer unit may include: a transfer mold configured to extend from an input point to an output point of the battery cell; and a transfer device configured to transfer the battery cell.

In an embodiment of the present invention, the transfer unit may have a plurality of unit moving sections, and the transfer device may reciprocate at one or more unit moving sections.

In an embodiment of the present invention, the transfer mold may include a recess in which the battery cell is positioned between one unit moving section and its adjacent unit moving section, and may be formed with a receiving groove recessed into the recess according to the shape of the battery cell.

In an embodiment of the present invention, the transfer device may include: a lifting unit configured to lift the battery cell from the transfer mold; and a driving unit configured to be coupled with the lifting unit so as to be movable and allow the lifting unit to reciprocate in a horizontal direction.

In an embodiment of the present invention, the lifting unit may include a hole for adsorbing the battery cell, and a vacuum may be applied through the adsorption hole to adsorb the battery cell.

In an embodiment of the present invention, the lifting unit may be a cylinder that reciprocates up and down by oil pressure or air pressure.

In an embodiment of the present invention, the battery cell may be a pouch type lithium secondary battery.

In the embodiment of the present invention, the battery cell may travel at a constant speed while the inspection unit performs the eddy current inspection.

In the embodiment of the present invention, the traveling speed of the battery cell in the inspection area may be controlled to be different from the traveling speed of the other areas.

In an embodiment of the invention, the eddy current signal is a voltage.

In an embodiment of the present invention, the apparatus may further include an optical sensor configured to transmit start and end time points of the eddy current generation and detection to the first and second sensors.

Further, the optical sensor may detect both ends of the electrode lead and transmit the detected ends to the first and second sensors.

Further, the eddy current check may be started by the detection signal at the first end, and the eddy current check may be ended by the detection signal at the second end.

[ advantageous effects ]

Since the crack detection apparatus inside a battery cell of the present invention detects the presence and location of cracks on an electrode, an electrode tab, and a welded part using eddy current, cracks in the battery cell can be detected in a non-destructive manner.

Drawings

Fig. 1 is a schematic view showing a principle of detecting cracks using eddy current.

Fig. 2 is a schematic view of a crack detection apparatus inside a battery cell according to an embodiment of the present invention.

Fig. 3 is a detailed view of an inspection unit according to another embodiment of the present invention.

Fig. 4 is a schematic view of coils inside the first sensor and the second sensor constituting the inspection unit of fig. 3.

Fig. 5 is a detailed view of an inspection unit and a transfer unit according to an embodiment of the present invention.

Fig. 6 is a schematic view illustrating the transfer unit of fig. 5.

Fig. 7 is a schematic view illustrating a transfer mold according to an embodiment of the present invention.

Detailed Description

The terms and words used in the present specification and claims should not be construed as being limited to general or dictionary terms, and the inventor can appropriately define the concept of the terms in order to best describe his invention. The terms and words should be interpreted as meanings and concepts consistent with the technical idea of the present invention. Therefore, the embodiments described in the specification and the configurations described in the drawings are only the most preferable embodiments of the present invention and do not represent all the technical ideas of the present invention. It should be understood that various equivalents and modifications may exist in place of them at the time of filing this application.

Further, throughout the specification, when an element is referred to as "comprising" an element, it is understood that the element may also comprise other elements unless specifically stated otherwise.

As used throughout this specification, the terms "about," "substantially," and the like are used to mean a value or the like when there are unique manufacturing and material tolerances, and are used to prevent the unfair use by unscrupulous infringers to contain accurate or absolute numerical disclosures to aid in the understanding of the present invention.

Throughout the specification, the term "combination thereof" contained in the expression of Markush (Markush) form means a mixture or combination of one or more selected from the elements described in the expression of Markush form, and it means including one or more selected from the above-mentioned moieties.

Throughout the specification, the expression "a and/or B" means "a or B or a and B".

Hereinafter, the present invention will be described in detail.

Fig. 1 is a schematic view showing a principle of detecting cracks using eddy current.

Referring to fig. 1, when an alternating current is applied to a coil 10, a primary magnetic field 20 is generated around the coil. At this time, when the coil 10 on which the primary magnetic field 20 is formed is disposed to the surface of the inspection object 50, induced electromotive force is generated in the surface of the inspection object 50 by electromagnetic induction. This induced electromotive force causes a current that disturbs the primary magnetic field 20 to flow, and this current is referred to as an eddy current 40.

The eddy current varies according to the state, position, defect, and material variation of the surface of the inspection object 50. The present invention detects cracks in the battery cell using the characteristics of the eddy current. That is, a battery cell to be inspected is passed between eddy current sensors, an eddy current signal is measured, and when the eddy current signal changes, it is considered that the eddy current signal has changed due to cracks of an electrode, an electrode tab, or a welded part. In this way cracks are detected.

Fig. 2 is a schematic view illustrating a crack detecting apparatus according to an embodiment of the present invention, and fig. 5 is a detailed view of an inspection unit and a transfer unit according to an embodiment of the present invention. Referring to these drawings, a crack detecting apparatus for detecting cracks in a battery cell using eddy current according to the present invention includes:

an inspection unit 110, the inspection unit 110 comprising: a first sensor for inducing eddy currents; a second sensor for sensing an eddy current signal induced by the first sensor and checking by an eddy current while the battery cell moves;

a transfer unit 120, the transfer unit 120 being configured to sequentially transfer the plurality of battery cells from a position where the battery cells are input to a position where the battery cells are taken out; and

a controller 130, the controller 130 configured to be electrically connected to the inspection unit and to receive, evaluate and control the eddy current signal sensed by the inspection unit.

In the present invention, the cracks in the battery cells mean cracks generated on the electrodes, the electrode tabs, and the welding parts.

The cracking of the electrode can be explained as follows. After applying an electrode mixture including an electrode active material, a binder, a conductive material, etc. onto a current collector, an electrode manufactured by electrode processing such as drying and rolling may have cracks on the current collector due to a difference in elongation, etc. between the current collector and the electrode mixture during the electrode processing. Such cracks may be referred to as cracks of the electrode.

The cracks of the electrode tab may be cracks due to a difference in elongation between the coated portion and the uncoated portion, or cracks due to vibration or external force during welding due to stress accumulation on wrinkles at the boundary.

The crack on the welded part may be a non-welded part formed due to insufficient welding during welding, or a crack generated during the welding process.

Since the inside of the battery cell is covered by the battery case when the electrode assembly is sealed by the battery case (such as a laminate sheet) through a sealing process, the cracks generated on the electrodes, the electrode tabs, and the welding parts listed above cannot be observed from the outside of the battery case. However, if the crack detection device using eddy current of the present invention is used, there is an effect that cracks can be detected.

Hereinafter, the inspection unit will be described in detail. Fig. 3 is a view showing the structure of an inspection unit according to an embodiment of the present invention. Referring to fig. 3, the inspection unit 110 of the present invention may be moved to a position to be inspected by the first and second sensors 111 and 112, and configured to perform induction of an eddy current and detection of an eddy current in a state where the first and second sensors 111 and 112 are fixed.

Specifically, the inspection unit includes:

a first sensor 111, the first sensor 111 configured to induce eddy currents;

a second sensor 112, the second sensor 112 configured to sense an eddy current signal induced by the first sensor 111;

a first position adjustment member 113, the first position adjustment member 113 being configured to be coupled to the first sensor 111 on one side and to be coupled to a third position adjustment member 117 by a position fixing bolt 115 on the other side;

a second position adjustment member 114, the second position adjustment member 114 configured to be coupled to the second sensor 112 on one side and to be coupled to a third position adjustment member 117 by a position fixing bolt 116 on the other side;

a third position adjusting member 117, the third position adjusting member 117 being configured to be coupled to the first position adjusting member 113 and the second position adjusting member 114, respectively, on one side, and to be coupled to a fourth position adjusting member 118 by a position fixing bolt 119 on the other side; and

a fourth position adjustment member 118, the fourth position adjustment member 118 being coupled to the third position adjustment member 117 by a position fixing bolt 119.

The portions of the first position adjustment member 113 and the second position adjustment member 114 coupled to the third position adjustment member 117, respectively, are spaced apart at predetermined intervals on the same extension line. The third position regulating member 117 is provided with a slide groove (not shown) having a predetermined length for regulating the positions of the first and second position regulating members. Further, the first position adjustment member and the second position adjustment member are movable along the slide groove.

Further, the fourth position regulating member 118 is provided with a slide groove having a predetermined length for regulating the position of the third position regulating member 117, and the third position regulating member 117 is movable along the slide groove.

According to the above embodiment, in order for the operator to move the first sensor 111 and the second sensor 112 to desired positions, the first position adjustment member 113 and the second position adjustment member 114, which are combined with the first sensor 111 and the second sensor 112, are designed to move in the vertical direction, respectively. Here, the vertical direction may be defined as a direction away from and close to the battery cell 200, which is an object to be inspected, in the vertical direction.

A sliding groove (not shown) for moving the first position adjustment member may be provided at a portion coupled with the first position adjustment member 113 on one side of the third position adjustment member 117. The first position adjustment member may move the moving slot within a length range of the moving slot. The moving groove has a shape extending in a vertical direction of the battery cell. The first position adjustment member 113 may be fixed to the third position adjustment member 117 by manipulating the position fixing bolt 115.

Similar to the first sensor, the second sensor 112 is coupled to one side of the second position adjustment member 114 such that the second sensor 112 can move in the vertical direction, and the other side of the first position adjustment member is designed to be combined with one side of the third position adjustment member 117. A sliding groove (not shown) for moving the second position adjustment member 114 may be provided at a portion coupled with the second position adjustment member on one side of the third position adjustment member 117. The second position adjustment member is movable along the slide groove, and can be fixed to the third position adjustment member by operating the position fixing bolt 116. The portions of the first position regulating member 113 and the second position regulating member 114 respectively coupled to the third position regulating member 117 are spaced apart at predetermined intervals on the same extension line.

The third position adjustment member is coupled to the fourth position adjustment member based on the same principle that the first and second position adjustment members are coupled to the third position adjustment member. The fourth position adjustment member may be provided with a slide groove (not shown) through which the third position adjustment member can move, the third position adjustment member can move within a length range of the slide groove, and the user moves the third position adjustment member to a desired position through the slide groove and then operates the position fixing bolt 119 to fix the third position adjustment member to the fourth position adjustment member.

Fig. 4 is a schematic diagram showing a first sensor and a second sensor. Referring to fig. 4, the first sensor 111 and the second sensor 112 each include a coil.

In one embodiment of the present invention, the first sensor and the second sensor are formed in a structure in which: the coil is wound on a magnetizing member (not shown) and may have a case surrounding the coil. In addition, a cover is formed at one end of the case, and an open shape may be formed at the other end of the case. The housing serves to protect the first and second sensors using eddy current from external impact, and to allow the first and second sensors to be easily mounted in other locations, for example, on a transfer unit or a position fixing member described later.

When an alternating current is applied to the coil of the first sensor 111, a primary magnetic field is formed around the coil. In this embodiment, the coil has a spring shape, but is not limited thereto. When a coil in which a primary magnetic field is formed is provided to a lithium secondary battery as an object to be inspected, induced electromotive force is generated in the lithium secondary battery due to electromagnetic induction, and eddy current flow of the primary magnetic field is disturbed. Thus, the first sensor induces an eddy current in the lithium secondary battery.

The second sensor 112 is located on the opposite surface of the first sensor 111 based on the battery cell as the object to be inspected. The second sensor is used for detecting an eddy current signal induced by the first sensor. The second sensor detects a decayed eddy current signal generated by decay (such as formation, reflection, and absorption of eddy current) of the eddy current induced by the first sensor due to factors such as a state, a position, a defect, and a material of the lithium secondary battery as an object to be inspected. Therefore, when there is a crack in the inside of the battery cell, a change in the eddy current signal occurs, and the second sensor detects the eddy current signal and transmits the eddy current signal to a controller described later.

In a preferred embodiment of the invention, the diameter of the coil is 0.5mm to 10 mm. Here, the diameter of the coil means a diameter in a horizontal section of the coil wound on the magnetic member or the magnetizing member. If the diameter of the coil is less than 0.5mm, the diameter is too small to detect an eddy current signal, and thus it may be difficult to detect cracks inside the secondary battery. In contrast, when the diameter of the coil exceeds 10mm, the noise adversely affects the detection of the internal crack, which is not desirable. Therefore, it is desirable to select an optimal coil diameter for detecting an internal crack while appropriately adjusting the coil diameter within the above numerical range.

When eddy currents are used for inspection, the distance between the coil and the surface to be inspected is called "lift-off". In order to improve the ability to detect defects on the surface to be inspected, it is desirable to keep the lift-off constant or to minimize it.

Hereinafter, the transfer unit 120 will be described.

Fig. 5 is a view of the crack inspection apparatus according to the embodiment of the present invention, as viewed from the top, and illustrates the inspection unit 110 and the transfer unit 120, and fig. 6 is a detailed view of the transfer unit 120 of fig. 5. Referring to these drawings, the transfer unit 120 includes: a transfer mold 121, the transfer mold 121 extending from an input point to an exit point of the battery cell; transfer devices 122, 123 and 124, the transfer devices 122, 123 and 124 being used for transferring the battery cells.

The battery cell 200 of the crack detection apparatus inside the battery cell of the present invention is transferred toward the inspection unit 110 by the transfer unit 120, and after the inspection is completed by the inspection unit 110, the battery cell 200 is carried to an outlet and taken out. The plurality of battery cells 200 are sequentially input to the transfer unit 120, and the battery cells are arranged and transferred at regular intervals.

The inspection unit 110 performs inspection using eddy current while the battery cell travels through the inspection region. During the inspection of the previous battery cell, the latter battery cell is transferred to a position where the previous battery cell was left. At this time, the latter battery cell may have a predetermined inspection waiting time, and when the former battery cell finishes the inspection and leaves the inspection area, the latter battery cell is transferred into the inspection area to start the inspection.

The inspection apparatus of the present invention may adjust the traveling speed of the battery cell in the inspection region to be different from the transfer speed of the battery cell outside the inspection region, if necessary. That is, the traveling speed of the battery cells in the inspection region may be slower than the transfer speed of the battery cells in the region other than the inspection region.

Referring to fig. 3 and 5, in the internal crack detection apparatus of the present invention, the first and second sensors are operated while the battery cell 200 to be inspected passes between the first and second sensors 111 and 112, and an eddy current inspection is performed in a state in which the battery cell 200 is interposed between the sensors 111 and 112. At this time, the battery cells are passed between the first and second sensors by transfer devices 122, 123, and 124, which will be described later. Also, while the eddy current inspection is performed by the first sensor and the second sensor, it is preferable that the battery cell travels in the inspection area at a constant speed.

Referring to fig. 6 showing an embodiment of the transfer unit 120 of the present invention, the transfer mold 121 of the transfer unit 120 of the present invention may include transfer devices 122, 123, and 124 for transferring the battery cells. And the transfer means may comprise: a lifting unit 122 for lifting the battery cell from the transfer mold; and a driving unit 124, the lifting unit 122 being movably coupled to the driving unit 124, and the driving unit 124 displacing the lifting unit in a cell transferring direction. Various forms may be adopted as long as the driving unit moves the lifting unit.

The lifting unit may be a cylinder that reciprocates up and down by oil pressure or air pressure. Hereinafter, embodiments of the lifting unit will be described.

Referring to fig. 6, the lifting unit 122 extends in a direction parallel to the traveling direction of the battery cell 200, and has a narrow and long bar shape, and two long bars are spaced above and below a center line parallel to the longitudinal direction of the transfer mold (the traveling direction of the battery cell). These rectangular parallelepiped-shaped lifting units support the battery cells 200 and move the battery cells while moving together in the transfer direction of the battery cells as the driving unit 124 moves.

In one embodiment of the present invention, the lifting unit may include at least one or more adsorption holes 123 for adsorbing the battery cells. The number of the adsorption holes 123 may be appropriately adjusted as necessary.

The lifting unit 122 adsorbs the battery cell to pick up the battery cell, and extends from the driving unit 124 and is lifted to adsorb the battery cell. In the driving unit 124, a surface opposite to a surface on which the battery cells are mounted based on the transport mold may be mounted on a lower surface of the transfer mold 121. In order for the lifting unit to pass through the transfer mold and ascend to the upper portion of the transfer mold, the transfer mold 121 may include an opening 125 at a portion corresponding to the lifting unit.

When the elevation unit extends from the driving unit and passes through the opening 125 of the transfer mold and ascends to the upper portion of the transfer mold, vacuum is applied through the adsorption hole 123, so that the battery cell is adsorbed and fixed to the elevation unit.

As described above, since the lifting unit can adsorb the battery cell, the internal crack detection apparatus of the present invention exhibits the following effects: the arrangement of the battery cells is disturbed, the battery cells are removed from the lifting unit, or the vibration of the battery cells can be suppressed. In the present invention for detecting eddy current induction and a change in eddy current signals while a battery cell is traveling, in order to improve inspection reliability, interference with the arrangement of the battery cells and vibration of the battery cells should be suppressed as much as possible while the battery cell is traveling. Since the crack detecting device of the present invention is provided with the suction hole on the lift unit, it has an effect of suppressing vibration even when the battery cell is traveling during the eddy current inspection, thereby improving the reliability of the inspection.

In the embodiment of the present invention, an embodiment in which vacuum is applied through the adsorption holes so as to adsorb the battery cell through the lifting unit is shown. Here, as long as the lifting unit can fix the battery cell, various forms may be adopted without being limited to the above-described method.

In one embodiment of the present invention, the transfer unit may have a plurality of unit moving sections, and the transfer device may perform the reciprocating motion at one unit moving section or at two or more unit moving sections. Thus, the transfer unit may have a plurality of transfer devices.

Referring to fig. 5, the transfer unit has a plurality of unit movement sections (a). The transfer device picks up a battery cell placed at the start point of a unit movement section and transfers the battery cell to the start point of an adjacent unit movement section. The transfer device that has completed the transfer of the battery cell in the unit movement section returns to the start point of the unit movement section again. The above process is repeated, and a plurality of battery cells are sequentially transferred.

Fig. 7 shows a portion of a transfer mold 121 according to an embodiment of the present invention, and referring to this figure, the transfer mold 121 may include a pocket 126 in which a battery cell is positioned between one cell movement section and an adjacent cell movement section in the pocket 126.

The recess recesses 126 are formed with receiving grooves filled therein according to the shape of the battery cells, and the battery cells 200 are seated on the recess recesses. As the battery cells are transferred from the input point to the inspection area, the arrangement of the battery cells may be disturbed. In the crack detecting device of the present invention, the recesses are provided on the transfer mold so that the battery cells are arranged by being seated on the recesses.

Referring to fig. 7, receiving grooves are formed in a direction parallel to and orthogonal to the traveling direction of the battery cells, respectively, to form an appearance in which a cross is embedded. This is for the purpose of performing the inspection in the longitudinal direction of the battery cell and in the width direction of the battery cell during the inspection of the battery cell.

The process of putting and taking out the battery cell 200 to be inspected into and from the inspection apparatus of the present invention will be described in detail.

The transfer mold constituting the transfer unit of the present invention is provided with a plurality of recesses.

If the battery cell is placed in a recess at the battery cell input point, the lifting unit 122 extends from the drive unit 124 in the direction of the transfer mold, and the lifting unit 122 rises through the opening 125 of the transfer mold 121.

The lifting unit 122 lifted to the upper portion of the transfer mold sucks and fixes the battery cell 200 seated on the recess. This is to minimize separation of the battery cell from the transfer device, misalignment during transfer, or movement of the battery cell during inspection. The method of the lifting unit adsorbing the battery cell is not limited to the above-described embodiment as long as the movement during the transfer of the battery cell can be minimized.

The lifting unit 122 is movably coupled to the driving unit 124 and can reciprocate by the operation of the driving unit. The elevation unit 122, which has adsorbed the battery cell, maintains the elevated state and moves toward the direction in which the inspection unit 110 has been mounted by the operation of the driving unit. At this time, the battery cell supported or adsorbed by the elevating unit is also transferred.

The lift unit transfers the adsorbed battery cell to an adjacent pocket, and the lift unit, which completes the transfer to the adjacent pocket, releases the vacuum. The lifting unit releasing the vacuum is again lowered toward the driving unit installed at the bottom of the transfer mold, and the driving unit is returned to the original position together with the lifting unit. Therefore, one battery cell is transferred from one unit movement section to an adjacent movement section. Then, the process is sequentially repeated, and the battery cell reaches the recess closest to the inspection unit 110 from the input point.

In one embodiment of the present invention, the internal crack inspection apparatus of the present invention may further include an alignment unit that aligns the battery cells disposed in the recess closest to the inspection unit. By arranging the battery cells immediately before the eddy current inspection, the reliability of the inspection can be improved.

The battery cells aligned by the aligning unit are again adsorbed to the elevating unit 122, travel through the inspection region, and are subjected to eddy current inspection by the first and second sensors.

In the inspection area of the inspection unit, it is preferable that the traveling speed of the battery cell is constant in order to improve the accuracy of the inspection. In addition, the traveling speed of the battery cell while passing through the inspection region may be controlled to be different from the transfer speed of the battery cell in other regions.

The battery cell, from which the eddy current inspection has been completed by the inspection unit, is transferred to a position where the battery cell is taken out by a transfer device including a lifting unit and a driving unit.

The controller 130 will be described in detail. The controller 130 constituting the crack detecting device of the present invention is electrically connected to the inspection unit 110, receives and evaluates the eddy current signal sensed by the inspection unit, and functions to control the detecting apparatus of the present invention.

The controller may receive and display information about the eddy current signal and determine the internal crack from the displayed image.

In one embodiment of the present invention, the eddy current signal detected by the inspection unit may be a voltage, and if there is a crack in the inside of the battery cell, the crack portion has a voltage variation. Therefore, the presence or absence of a crack and the position of the crack can be detected based on this.

The controller receives the voltage sensed by the inspection unit, records the voltage, and detects the presence and location of a crack from the profile of the voltage value according to the detection location.

The controller may control the inspection unit and the transfer device. The controller may be configured as a conventional programmable electronic computer coupled with memory for controlling the transfer and speed of the plurality of cells.

The crack detection device of the present invention determines cracks based on changes in eddy current signals, and is useful in detecting internal cracks in a pouch-type lithium secondary battery.

Hereinafter, the pouch type lithium secondary battery of the present invention will be described in detail.

In general, lithium secondary batteries may be classified according to the structure of an electrode assembly having a cathode/separator/anode structure. Representative examples thereof include: a jelly-roll (wound) electrode assembly in which a long sheet-type positive electrode and negative electrode are wound with a separator interposed therebetween; a stacked electrode assembly in which a plurality of positive electrodes and negative electrodes cut into units of a predetermined size are sequentially stacked with separators interposed therebetween; and a stacked/foldable electrode assembly in which bicells or full cells in which a predetermined unit of a positive electrode and a negative electrode are stacked with a separator interposed therebetween are wound.

In recent years, pouch-type batteries having a stacking or stacking/folding type electrode assembly embedded in a pouch-shaped battery case of an aluminum laminate sheet have attracted much attention due to their low manufacturing costs and light weight, and the amount of use thereof has gradually increased.

The pouch type lithium secondary battery includes: an electrode assembly; an electrode tab extending from the electrode assembly; an electrode lead welded to the electrode tab; and a battery case accommodating the electrode assembly.

The electrode assembly is a power generation device in which a positive electrode and a negative electrode are sequentially stacked with a separator interposed therebetween. The electrode assembly 130 has a stacking type structure or a stacking/folding type structure. An electrode tab extends from each electrode plate of the electrode assembly, and an electrode lead is electrically connected to the plurality of electrode tabs extending from each electrode plate, for example, by welding, and a portion of the electrode lead is exposed to the outside of the battery case. An insulating film is attached to a portion of the upper and lower surfaces of the electrode lead in order to increase the degree of sealing with the battery case and ensure an electrically insulating state.

The battery case is generally made of an aluminum laminate sheet, provides a space for accommodating the electrode assembly, and has a pouch shape as a whole. In the case of stacking the electrode assembly, the upper end of the inside of the battery case is spaced apart from the electrode assembly such that a plurality of positive electrode tabs and a plurality of negative electrode tabs can be combined with the electrode lead.

As described above, since the pouch type lithium secondary battery has the electrode, the electrode tab, and the welded portion inside the battery case, it is difficult to detect cracks from the outside, but if a detection device using an eddy current is used as in the present invention, cracks in the pouch type lithium secondary battery can be detected.

The crack detecting apparatus according to another embodiment of the present invention may further include an optical sensor that transmits the induction time of the eddy current and the end time of the detection of the eddy current signal to the inspection unit.

Specifically, when the optical sensor detects a first end of both ends of the electrode lead and transmits a detection signal to the inspection unit, the first and second sensors of the inspection unit operate to start inducing an eddy current and detecting an eddy current signal. When the optical sensor detects the second end of the two ends of the electrode lead and transmits a detection signal to the inspection unit, the operation of the first and second sensors of the inspection unit is terminated. As described above, by limiting the start and end times of the eddy current inspection by the inspection unit to the region of the electrode lead, the inspection range is reduced to a region included in the length of the electrode lead, thereby improving the detection sensitivity.

As described above, the electrode leads are electrically connected to each other by welding with the plurality of electrode tabs extending from each electrode plate, and the ends of the electrode leads can be recognized by the optical sensor as the electrode leads are withdrawn from the battery case.

The electrode lead includes a first end on one side and a second end on the other side, and the optical sensor moves from the first end to the second end and senses the first end and the second end. Specifically, the optical sensor recognizes a first end of one side of the electrode lead, and transmits a recognition signal to the first sensor. When the first sensor receives the identification signal from the optical sensor, it applies a current to the eddy current coil and finally starts eddy current induction in the lithium secondary battery. The optical sensor detects the second end while moving from the first end toward the second end, and transmits an identification signal to the second sensor when the second end is identified. When the second sensor receives the identification signal from the optical sensor, the second sensor ends receiving the eddy current signal.

The invention has been described with reference to the embodiments shown in the drawings, but this is only exemplary and those skilled in the art will understand that various modifications and other equivalent embodiments are possible. Therefore, the true technical scope of the present invention should be defined by the claims.

Description of the reference numerals

100: crack detection device in secondary battery

110: inspection unit

111: first sensor 112: second sensor

113: first position adjustment member 114: second position adjusting member

115. 116, 119: position fixing bolt

117: third position regulating member 118: fourth position adjusting member

120: transfer unit

121: the transfer mold 122: lifting unit

123: adsorption hole 124: drive unit

125: opening 126: recess seat

a: cell movement interval

130: controller

200: battery monomer