阅读说明：本技术 集流体、电芯及电池 (Current collector, battery core and battery ) 是由 谢斌 方双柱 盛东辉 于 2020-06-03 设计创作，主要内容包括：本发明实施例提供了一种集流体、电芯及电池,所述集流体,包括主体结构,所述主体结构上设置有强度削弱带,所述强度削弱带将所述主体结构分隔成至少两个部分,所述至少两个部分中的任两个部分之间通过导电材料连接。本发明实施例提供的集流体在应用在电池中时,有助于避免正极极片与负极极片因未断裂或部分断裂穿过破损隔膜而接触短路的情况,提高电池的安全性。(The embodiment of the invention provides a current collector, an electric core and a battery, wherein the current collector comprises a main body structure, the main body structure is provided with a strength weakening belt, the strength weakening belt divides the main body structure into at least two parts, and any two parts of the at least two parts are connected through a conductive material. When the current collector provided by the embodiment of the invention is applied to a battery, the situation that the positive pole piece and the negative pole piece penetrate through a damaged diaphragm to be in contact with a short circuit because of no fracture or partial fracture is avoided, and the safety of the battery is improved.)

1. The current collector is characterized by comprising a main body structure, wherein a strength weakening zone is arranged on the main body structure and divides the main body structure into at least two parts, and any two parts of the at least two parts are connected through a conductive material.

2. The current collector of claim 1, wherein in the case where the number of the strength weakening zones is plural, the plural strength weakening zones are arranged in parallel.

3. The current collector of claim 1, wherein the weakened strip extends along a length of the body structure.

4. The current collector of claim 3, wherein the length of the strength weakening zone is equal to the length of the body structure.

5. The current collector of claim 1, wherein the weakened strength strip comprises at least one of a thinned structure, an openwork structure, and a textured structure.

6. A battery cell comprising a pole piece comprising the current collector of any of claims 1 to 5.

7. The cell of claim 6, wherein a distance between a centerline of the first strength weakening zone and a centerline of the second strength weakening zone is less than or equal to 2 mm;

the pole piece comprises a first pole piece and a second pole piece which are arranged oppositely, the first strength weakening zone is a strength weakening zone corresponding to the first pole piece, and the second strength weakening zone is a strength weakening zone corresponding to the second pole piece and matched with the first strength weakening zone.

8. The cell of claim 6, wherein, when the cell is a wound cell, the corresponding strength weakening zone of the pole piece is parallel to a width direction of the wound cell.

9. The electrical core of claim 6, wherein the pole piece further comprises an active material coating layer; the active material coating layer is at least coated on the strength weakening belt included in the current collector.

10. A battery comprising the cell of any of claims 6 to 9.

Technical Field

The invention relates to the technical field of batteries, in particular to a current collector, a battery core and a battery.

Background

Lithium batteries have been widely used at present due to their advantages such as high energy density. The battery core of the lithium battery mainly comprises a positive pole piece, a negative pole piece and a diaphragm. Because the diaphragm has lower strength relative to the positive pole piece and the negative pole piece, the diaphragm may be damaged at some positions of the battery core under the accident condition, and the positive pole piece and the negative pole piece penetrate through the damaged diaphragm without being broken or partially broken to contact and short-circuit. Therefore, the existing lithium battery has the defect of low safety.

Disclosure of Invention

The embodiment of the invention provides a current collector, a battery cell and a battery, which aim to solve the problem of low safety of the conventional lithium battery.

In order to solve the technical problem, the invention is realized as follows:

the embodiment of the invention provides a current collector which comprises a main body structure, wherein a strength weakening zone is arranged on the main body structure, the main body structure is divided into at least two parts by the strength weakening zone, and any two parts of the at least two parts are connected through a conductive material.

The embodiment of the invention also provides a battery cell which comprises a pole piece, wherein the pole piece comprises the current collector.

The embodiment of the invention also provides a battery, which comprises the battery core.

In the embodiment of the invention, a strength weakening zone is arranged on the main body structure of the current collector, and the main body structure is divided into at least two parts by the strength weakening zone; when the current collector is acted by a destructive force, the main body structure of the current collector can be integrally broken at the strength weakening zone; the current collector provided by the embodiment is beneficial to avoiding the situation that the positive pole piece and the negative pole piece are contacted and shorted because the positive pole piece and the negative pole piece are not broken or partially broken and penetrate through the broken diaphragm when being applied to the battery, and the safety of the battery is improved.

Drawings

Fig. 1 is a schematic structural diagram of a current collector provided in an embodiment of the present invention;

fig. 2 is a schematic structural diagram of a positive electrode current collector and a negative electrode current collector in an embodiment of the invention;

FIG. 3 is a schematic structural diagram of a positive electrode plate and a negative electrode plate in an embodiment of the present disclosure;

FIG. 4 is a schematic diagram of an assembly structure of a positive electrode plate, a negative electrode plate and a diaphragm according to an embodiment of the present invention;

fig. 5 is a schematic structural diagram of a winding core in the embodiment of the invention.

Detailed Description

In order to make the technical problems, technical solutions and advantages of the present invention more apparent, the following detailed description is given with reference to the accompanying drawings and specific embodiments. In the following description, specific details such as specific configurations and components are provided only to help the full understanding of the embodiments of the present invention. Thus, it will be apparent to those skilled in the art that various changes and modifications may be made to the embodiments described herein without departing from the scope and spirit of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

As shown in fig. 1, a current collector 100 provided in an embodiment of the present invention includes a main body structure 110, and a strength weakening zone 120 is disposed on the main body structure 110, where the strength weakening zone 120 divides the main body structure 110 into at least two portions, and any two portions of the at least two portions are connected with each other through a conductive material.

It will be readily understood that the current collector, i.e. the part for collecting current, comprises a body structure which may be a metal foil, such as a copper foil or an aluminum foil, etc. The strength of the main structure of the existing current collector is generally equal everywhere, and when the current collector is subjected to destructive force, the current collector usually breaks at the position where the current collector is mainly subjected to the destructive force, and keeps connection at the position where the current collector is subjected to light force or unstressed force. In combination with practical applications, taking a lithium battery with a current collector as an example, because the strength of a diaphragm in the lithium battery is generally lower than that of the current collector, under the action of destructive force, the length of a broken position of the diaphragm is generally greater than that of a broken position of the current collector, and the strengths of a positive pole piece and a negative pole piece of the lithium battery are mainly provided by the current collector, therefore, the situation that an unbroken part and an unbroken part of the positive pole piece of the lithium battery are in mutual contact short circuit through the broken diaphragm is easy to occur, and the phenomena of heating, bulging and the like are slightly caused under the condition of short circuit, and serious people can cause the battery to smoke and catch fire, thereby bringing about a great safety problem.

In this embodiment, the main structure 110 included in the current collector 100 is provided with the strength weakening zone 120, and the strength of the portion of the main structure 110 corresponding to the strength weakening zone 120 is lower than the strength of the other portions of the main structure 110.

The strength weakening zone 120 divides the body structure 110 into at least two portions, any two portions of which are connected by the conductive material therebetween; for convenience of description, each of the at least two parts divided into is defined as a first part. It will be readily appreciated that for a current collector, the first portions are separated from one another by the strength-weakening zone 120 and still conduct electricity. For example, the first portion and the strength reducing band 120 are both components of the main structure 110, and the first portion and the solid portion of the strength reducing band 120, i.e. the first portion and the conductive material, may be integrally connected, except that the strength reducing band 120 is configured such that the different first portions are not continuous in the corresponding area of the main structure 110; as another example, the first portions may be conductive structures such as metal foils, the strength reducing strips 120 may be non-conductive structures such as plastic, and adjacent first portions may be made conductive by coating the strength reducing strips 120 with a conductive material. When the current collector 100 is impacted by a severe external force, the main structure 110 may be entirely broken at the strength weakening zone 120, and when the current collector 100 provided in this embodiment is applied to a lithium battery, a short circuit caused by mutual contact between an unbroken portion of a positive electrode sheet and an unbroken portion of a negative electrode sheet may be effectively avoided.

In the embodiment of the invention, a strength weakening zone is arranged on the main body structure of the current collector, and the main body structure is divided into at least two parts by the strength weakening zone; when the current collector is acted by a destructive force, the main body structure of the current collector can be integrally broken at the strength weakening zone; the current collector provided by the embodiment is beneficial to avoiding the situation that the positive pole piece and the negative pole piece are contacted and shorted because the positive pole piece and the negative pole piece are not broken or partially broken and penetrate through the broken diaphragm when being applied to the battery, and the safety of the battery is improved.

In some possible embodiments, the number of the strength weakening zones 120 provided on the above-described main body structure 110 may be one or more; however, the extending direction of the strength weakening zone 120 provided on the main body structure 110 may be along the length direction or the width direction of the main body structure 110, or along the oblique line direction or the curved line direction, etc., and the main body structure 110 may be divided into at least two parts, so that the main body structure 110 may be broken as a whole in the case of a breaking force.

In one application example, the strength weakening zone 120 extends along the length direction of the main structure 110 of the current collector 100, i.e., the extension direction of the strength weakening zone 120 is parallel to the length direction of the main structure 110, dividing the main structure 110 into two portions oppositely arranged in the width direction. When the current collector 100 is applied to a battery having a winding core, the current collector 100 in an initial state may be wound in a band shape, so that the strength weakening zones 120 on the main structure 110 of the wound current collector 100 can be distributed on the same cross section, so that the main structure 110 can be integrally broken when a destructive force is applied.

Also in the above application example, the number of the strength weakening zones 120 may be one, so as to ensure that the main body structure 110 can be integrally broken; the number of the strength weakening zones 120 may be plural, and the plurality of strength weakening zones 120 may be arranged in parallel, which facilitates the fracture of the corresponding section when the wound current collector 100 is subjected to a breaking force at different positions, thereby further improving the safety of the battery.

Further optionally, the length of the strength reduction zone 120 is equal to the length of the body structure 110. That is, the strength weakening zone 120 extends from one end surface of the body structure 110 in the longitudinal direction to the other end surface of the body structure 110 in the longitudinal direction; therefore, the situation that when the current collector 100 is subjected to destructive force, two ends or one end of the main body structure 110 in the length direction are still connected can be avoided to a certain extent, and the main body structure 110 can be further ensured to be integrally broken.

In another application, the current collector 100 may also be applied to a battery having laminated cells, in which case the arrangement of the strength weakening zone 120 on the main structure 110 may be more flexible, for example, the strength weakening zone 120 may extend in any direction to separate the main structure 110. In addition, when the number of strength-weakening zones 120 is plural, the plural strength-weakening zones 120 may be parallel or arranged non-parallel with a stagger; relatively speaking, arranging the plurality of strength weakening zones 120 in parallel can reduce the difficulty of processing the strength weakening zones 120.

Optionally, the strength weakening zone 120 includes at least one of a thinned structure, a hollowed structure, and a concave-convex structure.

For the thinning structure, it may refer to a groove or the like processed on the surface of the main body structure 110, and is used to reduce the thickness of the main body structure 110 at a corresponding position, so as to weaken the strength; the grooves can be continuous or discontinuous; for example, a groove having both ends reaching both edges of the main body structure 110 in the longitudinal direction may be provided, or a plurality of grooves may be intermittently arranged in the longitudinal direction of the main body structure 110, or a continuous zigzag groove may be provided in the main body structure 110. For the hollow structure, the opening may be a hole processed on the main body structure 110, and the opening may be at least one of a plurality of shapes such as a circle, a triangle, a quadrangle, a pentagon, and the like; the number of the openings can be a plurality of openings which are arranged discontinuously along a certain direction. For the concave-convex structure, it may refer to a structure in which protrusions and depressions provided on the surface of the body structure 110 are alternately arranged.

Through the setting of at least one of above attenuate structure, hollow out construction and concave-convex structure, can realize that intensity of intensity weakening area 120 is to the specific area's of major structure 110 effect of weakening.

In some possible embodiments, the strength-weakening zone 120 may be obtained by means of laser engraving, chemical etching, die stamping, metal engraving, and the like.

Optionally, a tab is further disposed on the main body structure 110.

When the current collector 100 is used in a battery having a wound cell, providing a tab on the main structure 110 of the current collector 100 helps to directly secure the tab in a winding center position when the main structure 110 is wound.

Referring to fig. 2 to fig. 4, an embodiment of the present invention further provides a battery cell, which includes a pole piece, where the pole piece 210 includes the current collector 100 described above.

It is readily understood that the strength of the pole piece 210 is provided primarily by the current collector 100, and in general, a fracture of the pole piece 210 may be considered a fracture of the current collector 100.

In general, the battery cell includes two types of pole pieces 210, namely a positive pole piece 211 and a negative pole piece 212, and the positive pole piece 211 and the negative pole piece 212 may both include the current collector 100 described in the above embodiments, so that the positive pole piece 211 and the negative pole piece 212 can be integrally broken at the same time when a destructive force is applied. Of course, in some possible embodiments, the current collector 100 having the strength weakening zone 120 may be provided only for the positive electrode tab 211 or only for the negative electrode tab 212, and the effect of avoiding the positive electrode tab 211 and the negative electrode tab 212 from contacting each other may also be achieved to some extent.

It should be noted that the battery cell is a battery cell to which the current collector 100 is applied, and all implementation manners in the embodiment of the current collector 100 are applicable to the embodiment of the battery cell, and the same technical effect can be achieved.

In the following, it is mainly taken as an example that all the pole pieces 210 in the battery cell have the corresponding strength weakening zone 120, that is, the strength weakening zone 120 is disposed on the main body structure 110 of the current collector 100 included in each pole piece 210.

Optionally, the distance between the centerline of the first intensity weakening zone and the centerline of the second intensity weakening zone is less than or equal to 2 mm;

the pole piece 210 includes a first pole piece and a second pole piece, which are oppositely disposed, the first strength weakening zone is a strength weakening zone 120 corresponding to the first pole piece, and the second strength weakening zone is a strength weakening zone 120 corresponding to the second pole piece and matching with the first strength weakening zone.

It is easily understood that the correspondence between the strength weakening zone 120 and the pole pieces 210 mainly refers to which pole piece 210 the strength weakening zone 120 is located in, for example, a first strength weakening zone may be disposed on the main structure 110 included in the current collector 100 included in the first pole piece, and a second strength weakening zone may be disposed on the main structure 110 included in the current collector 100 included in the second pole piece. The matching relationship between the first strength weakening zone and the second strength weakening zone may mean that the strength weakening zone 120 having the same or similar arrangement position as the extending direction exists between the two pole pieces 210 arranged adjacently.

In this embodiment, the distance between the center line of the first strength weakening zone and the center line of the second strength weakening zone is limited within a threshold, for example, within 2mm, so that the situation that the battery cell is difficult to completely break when being subjected to destructive force due to too much staggered strength weakening zones can be effectively avoided, a certain fault tolerance is provided, and the assembly difficulty of the battery cell is reduced.

Certainly, in some preferred embodiments, the center line of the first strength weakening zone and the center line of the second strength weakening zone may be completely overlapped, so that the battery cell can be effectively ensured to be completely broken when being subjected to a destructive force, and the safety of the battery cell is improved.

Optionally, the pole piece further comprises a membrane 220;

the first pole piece and the second pole piece are a positive pole piece and a negative pole piece respectively, and the diaphragm 220 is arranged between the positive pole piece and the negative pole piece.

The cell generally includes two types of pole pieces 210, namely a positive pole piece 211 and a negative pole piece 212, and the separator 220 may be disposed between the positive pole piece 211 and the negative pole piece 212. For example, the cell may be a wound cell or a laminated cell; for the wound battery cell, the positive electrode sheet 211, the separator 220, and the negative electrode sheet 212 may be sequentially arranged and then wound to obtain the wound battery cell, and certainly, in order to avoid mutual contact between the two electrode sheets during winding, the separator 220 may be additionally covered on the outer sides of the positive electrode sheet 211 and/or the negative electrode sheet 212; for a laminated cell, the positive pole pieces 211 and the negative pole pieces 212 may be alternately arranged, and the separator 220 may be disposed between any two adjacent pole pieces 210. By the arrangement of the diaphragm 220, the situation that the positive pole piece 211 is in direct contact with the negative pole piece 212 to cause short circuit is avoided.

Optionally, in a case where the battery cell is a wound battery cell, the strength weakening strip 120 corresponding to the pole piece 210 is parallel to a width direction of the wound battery cell.

In general, for a wound cell, the width direction corresponds to the direction perpendicular to the tab 130, and the strength weakening strip 120 extends in the length direction of the main structure 110, and after winding, is parallel to the width direction of the cell, i.e., the strength weakening strip 120 is located on a specific cross section of the wound cell.

The strength weakening belt 120 corresponding to the pole piece 210 is arranged to be parallel to the width direction of the wound battery cell, so that the wound battery cell can be integrally broken when being subjected to destructive force, and the short circuit caused by mutual contact of the positive pole piece 211 and the negative pole piece 212 is avoided.

Optionally, in a case that the battery cell is a laminated battery cell, the number of the pole pieces 210 is multiple, and the strength weakening zones 120 corresponding to multiple pole pieces 210 overlap or approximately overlap each other in a vertical projection.

For the laminated battery cell, the arrangement manner of the strength weakening zones 120 on the main structure 110 of the current collector 100 included in the pole pieces 210 is flexible, and in this embodiment, the positions of the strength weakening zones 120 corresponding to the pole pieces 210 on the main structure 110 are unified, so that the strength weakening zones 120 corresponding to the pole pieces 210 overlap or approximately overlap each other in a vertical projection, it is easily understood that the approximately overlapping may correspond to a case where the distance between the center line of the first strength weakening zone and the center line of the second strength weakening zone is less than a certain threshold value. So be favorable to when receiving the destructive power, lamination electricity core can wholly break.

Of course, it is readily understood that a laminated cell may include a plurality of cell units, each cell unit consisting essentially of one positive pole piece 211, one negative pole piece 212, and a separator 220. In some possible embodiments, the positions of the two pole pieces 210 in each cell unit corresponding to the strength weakening belt 120 may be matched, and the positional relationship between the pole pieces 210 in different cell units corresponding to the strength weakening belts 120 is not limited, and the effect of avoiding the positive pole piece 211 and the negative pole piece 212 from contacting each other can also be achieved to some extent.

Optionally, the pole piece 210 further comprises an active material coating layer; the active material coating layer is coated on at least the strength weakening zone 120 included in the current collector 100.

The active material coating layer may be a positive electrode coating layer or a negative electrode coating layer, and in this embodiment, the active material coating layer is at least coated on the strength weakening zone 120 included in the current collector 100, so as to ensure that the battery cell can realize a conventional charge and discharge function; of course, in some preferred embodiments, the active substance coating layer may be applied to both the strength-weakening zone 120 and the main structure 110.

In one example, the number of the pole pieces 210 is multiple, a plurality of the pole pieces 210 have a positive pole piece 211 and a negative pole piece 212, a positive coating layer 231 is disposed on the current collector 100 included in the positive pole piece 211, and a negative coating layer 232 is disposed on the current collector 100 included in the negative pole piece 212.

For convenience of description, the current collector 100 included in the positive electrode tab 211 is hereinafter referred to as a positive electrode current collector, and the current collector 100 included in the negative electrode tab 212 is hereinafter referred to as a negative electrode current collector.

Taking the above-mentioned battery cell as a winding battery cell as an example, the winding battery cell can be manufactured by the following steps:

(1) referring to fig. 2, two foils are respectively used as the main structure 110 of the positive electrode current collector and the main structure 110 of the negative electrode current collector; for convenience of description, the main structure 110 of the positive electrode current collector is referred to as a positive electrode main structure 111, and the main structure 110 of the negative electrode current collector is referred to as a negative electrode main structure 112;

the positive electrode main body structure 111 and the negative electrode main body structure 112 are respectively provided with the strength weakening zones 120, the strength weakening zones 120 on the two main body structures 110 may be mutually corresponding in position, extending direction and number, only one strength weakening zone 120 is shown on each main body structure 110 in the figure, and in practical application, the number of the strength weakening zones 120 on each main body structure 110 may be one or more;

(2) referring to fig. 3, a positive electrode active material (corresponding to the positive electrode coating layer 231 described above) is coated on the positive electrode current collector to prepare a positive electrode sheet 211; coating a negative active material (corresponding to the negative coating layer 232) on the negative current collector to prepare a negative pole piece 212;

in addition, the positive electrode main body structure 111 and the negative electrode main body structure 112 may be respectively fixed with corresponding tabs 130;

(3) referring to fig. 4, a separator 220 is disposed between the positive electrode tab 211 and the negative electrode tab 212, so as to prevent the positive electrode tab 211 and the negative electrode tab 212 from contacting each other during the winding process, the separator 220 may be disposed on the other side of the positive electrode tab 211 opposite to the negative electrode tab 212, and/or on the other side of the negative electrode tab 212 opposite to the positive electrode tab 211;

(4) referring to fig. 5, winding the structure obtained in step (3) to obtain a winding core 300; at this time, the strength weakening zones 120 are overlapped by winding in the downward direction of the view shown in fig. 5, and are parallel to the width direction of the core 300;

of course, in practical applications, the number of the strength-weakening zones 120 in the wound cell may be one or more, and when there are a plurality of strength-weakening zones 120, the plurality of strength-weakening zones 120 may be parallel to each other.

(5) The winding core 300 is subjected to packaging, liquid injection and formation treatment to obtain a winding battery cell.

In addition, for the laminated battery cell, the manufacturing steps are similar to those of the above wound battery cell, and in the case of removing the tab 130 in step (2), the structure obtained in step (3) may be laminated, which is not described herein again.

The embodiment of the invention also provides a battery, which comprises the battery core.

The battery in this embodiment may be a lithium battery.

It should be noted that the battery is a battery to which the battery cell is applied, and all implementation manners in the above-described embodiment of the battery cell are applicable to the embodiment of the battery, and the same technical effect can be achieved.

While the preferred embodiments of the present invention have been described, it will be understood by those skilled in the art that various changes and modifications may be made without departing from the spirit and scope of the invention as defined in the following claims.