CN219419078U

CN219419078U - Battery device

Info

Publication number: CN219419078U
Application number: CN202320659461.4U
Authority: CN
Inventors: 胡恩广; 赵璐涵; 张士荟
Original assignee: China Innovation Aviation Technology Group Co ltd
Current assignee: China Innovation Aviation Technology Group Co ltd
Priority date: 2023-03-29
Filing date: 2023-03-29
Publication date: 2023-07-25
Anticipated expiration: 2033-03-29
Also published as: DE202023102580U1

Abstract

The utility model relates to the technical field of batteries, in particular to a battery device, which comprises a battery and a box body, wherein the battery comprises a shell, a battery core and a pole, and a containing cavity is arranged in the shell; the battery cell is arranged in the accommodating cavity and comprises a pole piece, and a concave part for accommodating electrolyte is arranged on the pole piece; the battery is characterized in that the pole is arranged on the battery shell, the pole is connected with the battery core, the box body is provided with a bottom plate, the battery is arranged on the box body, and the pole is arranged at one end of the shell, which faces the bottom plate. Through set up the depressed part that is used for holding electrolyte on the pole piece of electric core, can retrain electrolyte in electric core, reduced free electrolyte in the battery, avoid a large amount of electrolyte to free to the utmost point post, realized the protection to the utmost point post, and then reduce the fault rate of battery to a certain extent at least.

Description

Battery device

Technical Field

The disclosure relates to the technical field of batteries, and in particular relates to a battery device.

Background

Battery devices are often provided in electric vehicles for powering the electric vehicles. The battery device has a plurality of batteries electrically connected (in series or in parallel), a post for electrical connection provided on the battery, and an electrolyte in the battery. After the free electrolyte in the cell contacts the post, the post may be corroded, resulting in failure of the cell.

It should be noted that the information disclosed in the above background section is only for enhancing understanding of the background of the present disclosure and thus may include information that does not constitute prior art known to those of ordinary skill in the art.

Disclosure of Invention

The present disclosure provides a battery and a battery device, and further reduces the failure rate of the battery device at least to some extent.

The present disclosure provides a battery device including:

the battery comprises a shell, a battery cell and a pole column, wherein a containing cavity is formed in the shell, the battery cell is arranged in the containing cavity, the battery cell comprises a pole piece, a concave part for containing electrolyte is formed in the pole piece, the pole column is arranged in the shell, and the pole column is connected with the battery cell;

the box, the box has the bottom plate, the battery is located the box, and the utmost point post is located the casing is towards the one end of bottom plate.

The embodiment of the disclosure provides a battery device, including battery and box, the battery includes casing, electric core and utmost point post, and the holding chamber in the casing is located to the electric core, and the casing is located to the utmost point post, sets up the depressed part that is used for holding electrolyte on the pole piece of electric core, can retrain electrolyte in the electric core, has reduced free electrolyte in the battery, and a large amount of electrolyte when having avoided the utmost point post of battery to be close to the bottom plate setting is free to the utmost point post, has realized the protection to the utmost point post, and then reduces battery device's fault rate to a certain extent at least.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the disclosure.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the disclosure and together with the description, serve to explain the principles of the disclosure. It will be apparent to those of ordinary skill in the art that the drawings in the following description are merely examples of the disclosure and that other drawings may be derived from them without undue effort.

Fig. 1 is a schematic structural view of a battery device according to an exemplary embodiment of the present disclosure;

fig. 2 is a schematic structural view of a battery according to an exemplary embodiment of the present disclosure;

fig. 3 is a schematic structural diagram of a first cell according to an exemplary embodiment of the present disclosure;

fig. 4 is a schematic structural diagram of a second type of battery cell according to an exemplary embodiment of the present disclosure;

fig. 5 is a schematic structural diagram of a third cell according to an exemplary embodiment of the present disclosure.

Detailed Description

The technical solutions in the exemplary embodiments of the present disclosure will be clearly and completely described below with reference to the accompanying drawings in the exemplary embodiments of the present disclosure. The example embodiments described herein are for illustrative purposes only and are not intended to limit the scope of the present disclosure, and it is therefore to be understood that various modifications and changes may be made to the example embodiments without departing from the scope of the present disclosure.

In the description of the present disclosure, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance unless explicitly specified or limited otherwise; the term "plurality" refers to two or more than two; the term "and/or" includes any and all combinations of one or more of the associated listed items. In particular, references to "the/the" object or "an" object are likewise intended to mean one of a possible plurality of such objects.

Unless specified or indicated otherwise, the terms "connected," "fixed," and the like are to be construed broadly and are, for example, capable of being fixedly connected, detachably connected, or integrally connected, electrically connected, or signally connected; "coupled" may be directly coupled or indirectly coupled through intermediaries. The specific meaning of the terms in the present disclosure may be understood by those skilled in the art according to the specific circumstances.

Further, in the description of the present disclosure, it should be understood that the terms "upper", "lower", "inner", "outer", and the like, as described in the example embodiments of the present disclosure, are described with the angles shown in the drawings, and should not be construed as limiting the example embodiments of the present disclosure. It will also be understood that in the context of an element or feature being connected to another element(s) "upper," "lower," or "inner," "outer," it can be directly connected to the other element(s) "upper," "lower," or "inner," "outer," or indirectly connected to the other element(s) "upper," "lower," or "inner," "outer" via intervening elements.

The exemplary embodiments of the present disclosure provide a battery device, as shown in fig. 1 and 2, including a battery 100 and a case 200, the battery 100 including a housing 10, a battery cell 20, and a post 30, the housing 10 having a receiving cavity therein; the battery cell 20 is arranged in the accommodating cavity. As shown in fig. 3, the battery cell 20 comprises a pole piece 21 and a diaphragm 23, and concave parts 22 for containing electrolyte are arranged on two opposite surfaces of the pole piece 21; the pole 30 is provided to the housing 10, and the pole 30 is connected to the battery cell 20. The case 200 has a bottom plate 210, the battery 100 is provided to the case 200, and the post 30 is provided to an end of the case 10 facing the bottom plate 210.

The battery device provided by the embodiment of the disclosure, including battery 100 and box 200, battery 100 includes casing 10, electric core 20 and utmost point post 30, the holding chamber in casing 10 is located to electric core 20, casing 10 is located to utmost point post 30, be provided with the depressed part 22 that is used for holding electrolyte on the pole piece 21 of electric core 20, can retrain electrolyte in electric core 20, free electrolyte in the battery 100 has been reduced, a large amount of electrolyte free extremely post 30 when having avoided utmost point post 30 to set up towards bottom plate 210, realized the protection to utmost point post 30, and then the fault rate of battery 100 is reduced to at least a certain extent.

The following will describe each part of the battery device provided in the embodiments of the present disclosure in detail:

the battery 100 provided in the embodiment of the present disclosure may be a rectangular parallelepiped battery, and the housing 10 may be a rectangular parallelepiped or approximately rectangular parallelepiped structure, and a through hole is provided in the housing 10, through which the pole 30 is inserted. The post 30 includes a main body portion, a first connection portion, and a second connection portion, the main body portion is inserted into a through hole in the housing 10, the first connection portion is connected with the main body portion, and the main body portion is located in the housing 10, and the first connection portion is connected with the battery cell 20 (the first connection portion is welded with a tab of the battery cell 20, or the first connection portion is connected with the tab through an adapter). The second connection part is connected to the body part, and the second connection part is located outside the case 10, and is used to connect conductive devices (e.g., bus bars, etc.) outside the battery 100.

The housing 10 may include a housing body having an opening therein and a cover plate plugged at the opening of the housing body. By way of example, the housing 10 may include two oppositely disposed first surfaces and four second surfaces between the two first surfaces, the first surfaces having an area greater than the area of the second surfaces. The opening of the housing body may be located on a first surface, and the cover plate seals the opening, that is, the cover plate forms a first surface of the housing 10. Alternatively, the opening of the housing body may be located on a second surface, and the cover plate seals the opening, that is, the cover plate forms a second surface of the housing 10.

Optionally, the housing 10 is provided with a first pole and a second pole, where the first pole is connected to one tab of the electric core 20, and the first pole is connected to the other tab of the electric core 20. The first and second poles may be provided on a cover plate of the case 10.

An electrolyte is also disposed within the housing 10 of the battery 100, and wets at least a portion of the cells 20 when the battery 100 is inverted (the poles 30 are facing the bottom plate 210). The case 10 of the battery 100 may be provided with a liquid filling hole, and after the battery cell 20 is mounted in the case 10, an electrolyte is filled into the case 10 through the liquid filling hole. After the electrolyte is injected, the electrolyte injection hole is closed by the plugging piece.

It is understood that the battery 100 provided in the embodiment of the present disclosure is not limited to the rectangular battery 100, for example, the battery 100 may be a cylindrical battery, and the housing 10 in the cylindrical battery has a hollow cylindrical structure. The electrode post 30 is provided on one end face of the case 10 of the battery 100, the electrode post 30 serving as one electrode of the battery 100, and the case 10 serving as the other electrode of the battery 100.

The battery cell 20 comprises a plurality of pole pieces 21, and a concave portion 22 for containing electrolyte is arranged on at least part of the pole pieces 21 in the plurality of pole pieces 21. The pole piece 21 may be provided with a plurality of concave portions 22, and the plurality of concave portions 22 are discretely distributed on the pole piece 21.

The position of the concave part 22 close to the first edge of the pole piece 21 and the first edge of the pole piece 21 are provided with a preset distance, wherein the preset distance is more than or equal to 5mm, and the first edge of the pole piece 21 is the edge of the pole piece 21 close to the pole post 30. By setting the preset distance between the recess 22 and the first edge of the pole piece 21 to be equal to or greater than 5mm, the distance between the recess 22 and the pole 30 can be ensured, free electrolyte is prevented from being accumulated on the pole 30, and the pole 30 is further protected.

In one possible embodiment, the cells 20 are wound cells. Namely, the first pole piece, the second pole piece opposite to the first pole piece and the diaphragm 23 arranged between the first pole piece and the second pole piece are wound to obtain the winding type battery cell. For example, as shown in fig. 5, the first electrode sheet is a positive electrode sheet 211, and the second electrode sheet is a negative electrode sheet 212.

As shown in fig. 4, the pole piece 21 includes a flat region 201 and a bending region 202, the flat region 201 is provided with a first recess 221, the bending region 202 is provided with a second recess 222, and the depth of the second recess 222 is greater than that of the first recess 221.

In the related art, on the winding core after hot pressing, the gap between the pole pieces in the bending region 202 is larger than the gap between the pole pieces in the flat region 201, and the liquid storage capacity of the bending region 202 is better than that in the flat region in the initial stage of the battery 100. However, as the battery 100 undergoes large-area swelling during multiple charge and discharge cycles, i.e., the pole pieces of the flat area 201 expand and bend outwards, the pole piece gaps of the flat area 201 become larger; the pole piece of the bending region 202 is pulled when the pole piece of the flat region 201 is outwards expanded and bent, so that the curvature of the pole piece of the bending region 202 is reduced, the gap between the pole piece and the pole piece is gradually reduced, and finally the gap between the pole piece of the bending region 202 is possibly even smaller than the gap between the pole pieces of the flat region 201, so that the liquid storage amount of the bending region 202 is smaller and smaller; after the pole piece in the bending area 202 is bent, the n/p ratio of the positive pole to the negative pole at the corner of the pole piece is smaller than the design value, and the reasons are that the risk of lithium precipitation of the pole piece in the bending area 202 is higher than that of the pole piece in the flat area 201, and the requirement on electrolyte storage is larger. Setting the depth of the second recess 222 to be greater than the depth of the first recess 221 can solve the above-described problem.

When the battery 100 has a rectangular parallelepiped or approximately rectangular parallelepiped structure, the battery cells 20 may have approximately rectangular parallelepiped structures, with rounded corner structures on two opposite sides of the battery 100, which are formed when the battery cells 20 are wound. The area of the pole piece 21 corresponding to the rounded corners of the cell 20 is a bending area 202, and the area corresponding to the plane of the cell 20 is a flat area 201.

By way of example, the depth of the first recess 221 is 7 μm-18 μm, e.g., the depth of the first recess 221 is 7 μm, 8 μm, 10 μm, 15 μm, 18 μm, etc. The depth of the second recess 222 is 25 μm to 75 μm, for example, the depth of the second recess 222 is 25 μm, 26 μm, 30 μm, 40 μm, 47 μm, 60 μm, 75 μm, or the like.

It should be noted that, in the embodiment of the present disclosure, the depth of the first recess 221 refers to a distance from an end of the first recess 221 away from the flat area 201 to the flat area 201. The depth of the second recess 222 refers to the distance from the end of the second recess 222 away from the inflection region 202 to the inflection region 202.

The flat area 201 is provided with at least one first recess 221, the total projected area of the first recess 221 in the flat area 201 accounting for 3% -30% of the flat area 201. For example, the total projected area of the first recess 221 in the flat region 201 is 3%, 4%, 7%, 10%, 20% or 30% of the flat region 201. The bending region 202 is provided with at least one second concave portion 222, and the total projected area of the second concave portion 222 in the bending region 202 accounts for 5% -50% of the bending region 202. For example, the total projected area of second recess 222 at inflection region 202 is 5%, 8%, 10%, 30%, 40% or 50% of inflection region 202.

Wherein, the total projected area of the first concave portions 221 in the flat area 201 refers to the sum of the projected areas of all the first concave portions 221 in the flat area 201. The total projected area of the second concave portions 222 in the bending region 202 refers to the sum of the projected areas of all the second concave portions 222 in the bending region 202. It should be noted that, in the embodiment of the present disclosure, the area of the bending region 202 is the area of the bending region 202 after being unfolded into a plane, and the area of the second concave portion 222 in the projection region of the bending region 202 is the area of the second concave portion 222 in the projection region of the bending region 202 when the area of the projection region of the bending region 202 is also the area of the bending region unfolded into a plane.

By setting the total projected area of the first concave portion 221 in the flat area 201 to be 3% -30% of the flat area 201, and setting the total projected area of the second concave portion 222 in the bending area 202 to be 5% -50% of the bending area 202, it is ensured that an enough drainage path is provided to guide the electrolyte to each part of the battery 100, and it is ensured that the battery cell 20 has enough storage space, so that excessive electrolyte is prevented from being in a free state.

The pole piece 211 comprises a conductive layer and active material layers coated on both sides of the conductive layer. The recess 22 is formed in the active material layer; alternatively, the conductive layer is formed with pits, and the active material layer and the conductive layer are disposed in a conformal manner to form the depressions 22.

The formation of the recess 22 in the active material layer means that the recess 22 is only provided on the active material layer, for example, the recess 22 may be formed on the active material layer by laser drilling, and no recess is provided on the conductive layer. The conductive layer is provided with pits, and the active material layer and the conductive layer are arranged along with the shape, which means that the active material layer and the conductive layer are deformed to form a concave part by stamping or rolling. For example, the shape of the recess 22 on the pole piece 21 may be prismatic (e.g., triangular prism, quadrangular prism, or hexagonal prism), conical, pyramidal, hemispherical, bowl-shaped, disk-shaped, inverted truncated cone-shaped, or drop-shaped.

In the winding type battery cell, the first pole piece is a positive pole piece 211, and the second pole piece is a negative pole piece 212. The pole piece 21 includes a current collector, the current collector of the positive pole piece 211 is an aluminum current collector, the current collector of the negative pole piece 212 is a copper current collector, and the thickness of the aluminum current collector is greater than that of the copper current collector.

In the embodiment of the present disclosure, the positive electrode piece 211 is provided with a concave portion 22, and the negative electrode piece 212 is not provided with the concave portion 22, that is, the negative electrode piece 212 has a smooth surface structure. In practical application, the material is easy to fall off from the negative electrode plate 212, so that the process requirement of arranging the concave part 22 on the negative electrode plate 212 is high, the quality of the battery can be influenced by the material falling of the negative electrode during processing, the concave part 22 is arranged on the positive electrode plate 211, the process requirement of battery production can be reduced by not arranging the concave part 22 on the negative electrode plate 212, and the quality of the battery is improved.

The positive current collector is an aluminum current collector, the negative current collector is a copper current collector, and the thickness of the aluminum current collector is greater than that of the copper current collector. The concave part 22 is arranged on the aluminum current collector with larger thickness, the process is simpler and easy to realize, the problem that the concave part 22 is damaged due to small thickness of the copper current collector is avoided, the electrolyte is accommodated through the concave part 22, the product quality can be effectively improved, and the production cost and the yield can be controlled.

It is to be understood that in the embodiment of the present disclosure, the positive electrode piece 211 may be provided with a recess 22, and the negative electrode piece 212 may be provided with a recess 22. The concave parts 22 are arranged on the positive electrode plate 211 and the negative electrode plate 212, so that the capacity of electrolyte between the adjacent electrode plates 21 can be increased, and the free electrolyte in the battery 100 can be further reduced.

In another possible embodiment, the battery cell 20 is a laminated battery cell, and the battery cell 20 includes a plurality of stacked pole pieces 21, and at least some of the pole pieces 21 are provided with a recess 22.

The laminated cell comprises a plurality of pole pieces 21 which are stacked, and a diaphragm 23 is arranged between two adjacent pole pieces 21 in the plurality of pole pieces 21 which are stacked. The pole piece 21 includes a tab region for forming the tab of the battery cell 20, and a paint region, which is a main body region of the pole piece 21, for coating an electrode material.

The tab area is provided on a side of the paint area, and the tab area is a protrusion of an edge of the paint area. The coating region may be rectangular or nearly rectangular in configuration, as may the tab region. The length of the edge where the tab region and the paint region are connected is smaller than the length of the edge of the paint region.

The plurality of pole pieces 21 may include a positive pole piece 211 and a negative pole piece 212, and the positive pole piece 211 and the negative pole piece 212 may be alternately arranged in the stacking process, and a separator is disposed between adjacent positive pole pieces 211 and negative pole pieces 212.

The electrode tab 21 may include a current collector (conductive layer) and an electrode coating (active material layer) applied to a surface of the current collector. In practical application, the electrode powder may be mixed into a coating solution, the coating solution is applied to a current collector, and then the electrode sheet 21 is formed through processes such as a pair roller and a die cutting.

The current collector of the positive electrode plate 211 is an aluminum current collector, and the surface of the aluminum current collector is coated with a positive electrode material to form the positive electrode plate 211. The current collector of the negative electrode sheet 212 is a copper current collector, and a negative electrode material is coated on the copper current collector to form the negative electrode sheet 212. The thickness of the aluminum current collector is greater than the thickness of the copper current collector. Of course, in other embodiments, other materials may be used for the current collector, and the embodiment of the disclosure is not limited thereto.

The positive electrode piece 211 is provided with a concave portion 22, and the negative electrode piece 212 is not provided with the concave portion 22, that is, the negative electrode piece 212 is in a planar structure. In practical application, the material is easy to fall off from the negative electrode plate 212, so that the process requirement of arranging the concave part 22 on the negative electrode plate 212 is high, the quality of the battery can be influenced by the material falling of the negative electrode during processing, the concave part 22 is arranged on the positive electrode plate 211, the process requirement of battery production can be reduced by not arranging the concave part 22 on the negative electrode plate 212, and the quality of the battery is improved.

In the laminated cell, the positive current collector is an aluminum current collector, the negative current collector is a copper current collector, and the thickness of the aluminum current collector is greater than that of the copper current collector. The concave part 22 is arranged on the aluminum current collector with larger thickness, so that the process is simpler and easy to realize. Or the positive electrode piece 211 is provided with a concave portion 22, and the negative electrode piece 212 is also provided with a concave portion 22. The recess 22 is disposed in each of the positive electrode tab 211 and the negative electrode tab 212, which is not limited in this embodiment.

In the battery 100 provided in the embodiment of the present disclosure, the concave portions 22 on the pole pieces 21 on both sides of the separator 23 may be oppositely disposed, or the concave portions 22 on the pole pieces 21 may be disposed in the same direction. Illustratively, the recesses 22 on adjacent pole pieces 21 are disposed opposite one another. The first pole piece is provided with the third depressed part towards the one side of second pole piece, and the one side of second pole piece towards first pole piece is provided with the fourth depressed part, and the orthographic projection of third depressed part on the second pole piece is at least partly and the third depressed part does not coincide, and first pole piece and second pole piece are the pole piece 21 of the both sides of diaphragm 23.

The third concave part on the first pole piece is not overlapped with the fourth concave part on the second pole piece, so that the third concave part and the fourth concave part are at least partially embedded, the phenomenon that the performance of the pole lug is influenced due to too dense concave parts 22 on one pole lug is avoided, and the accommodating space of electrolyte is also considered.

Optionally, a plurality of third concave portions are disposed on the first pole piece, and the plurality of third concave portions are discretely distributed on the first pole piece. The second pole piece is provided with a plurality of fourth concave parts, and the fourth concave parts are discretely distributed on the second pole piece. The third concave parts and the fourth concave parts are arranged in a staggered mode, namely, the fourth concave parts are projected on the first pole piece and are positioned in gaps of the third concave parts.

The battery device may be a battery pack, a battery module, a battery pack, or the like. The battery pack includes a plurality of sequentially arranged batteries 100, and when the plurality of batteries 100 are arranged, large surfaces of adjacent batteries 100 are opposed. The battery module may include a battery pack and end plates (end insulating plates) provided at ends of the battery pack in the arrangement direction of the batteries 100, the end plates being provided at both ends of the battery pack, respectively.

The battery pack may include a case 200 and a plurality of batteries 100, the case 200 including a base plate 210 and a frame 220, the frame 220 being connected to the base plate 210 to form one or more battery compartments, the batteries 100 being disposed in the battery compartments. The bottom plate 210 is used for supporting the battery 100, and the frame 220 is used for limiting the battery 100.

The battery 100 is provided to the case 200, and the post 30 is provided to one end of the case 10 facing the bottom plate 210. The post 30 of the battery 100 may be provided at the top of the battery 100, and the battery 100 is in an inverted state within the case 200. When the battery 100 is in the inverted state, the free electrolyte in the battery 100 is easily accumulated at the electrode post 30, and corrodes the electrode post 30. In the embodiment of the disclosure, by placing the electrolyte in the recess 22 on the pole piece 21, free electrolyte is reduced and protection of the pole 30 is achieved.

The battery device provided by the embodiment of the disclosure includes a battery 100 and a box 200, in the battery 100, a battery core 20 is arranged in a containing cavity in a shell 10, a pole column 30 is arranged in the shell 10, a concave part 22 for containing electrolyte is arranged on a pole piece 21 of the battery core 20, the electrolyte can be restrained in the battery core 20, free electrolyte in the battery 100 is reduced, a large amount of electrolyte is prevented from being free to the pole column 30, the protection of the pole column 30 is realized, the failure rate of the battery device is reduced to at least a certain extent, and the service life of the battery device is prolonged.

The battery device provided by the embodiment of the disclosure can be applied to an electric vehicle, and when the battery device is used for the electric vehicle, the battery device can be a battery pack which is installed on the electric vehicle and provides energy for the electric vehicle.

In practice, the battery pack may be mounted to the frame of an electric vehicle. The battery pack can be fixedly connected with the frame. Or the battery pack can be a modularized battery pack which can be detachably connected to the vehicle body, so that the battery pack is convenient to replace.

Other embodiments of the disclosure will be apparent to those skilled in the art from consideration of the specification and practice of the disclosure disclosed herein. This application is intended to cover any adaptations, uses, or adaptations of the disclosure following, in general, the principles of the disclosure and including such departures from the present disclosure as come within known or customary practice within the art to which the disclosure pertains. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the disclosure being indicated by the following claims.

Claims

1. A battery device, characterized in that the battery device comprises:

2. The battery device of claim 1, wherein a plurality of the recesses are provided on the pole piece.

3. The battery device of claim 2, wherein the cell is a coiled cell, the pole piece comprises a flat region and a bent region, the flat region is provided with a first recess, the bent region is provided with a second recess, and the depth of the second recess is greater than the depth of the first recess.

4. The battery device of claim 3, wherein the first recess has a depth of 7 μm to 18 μm and the second recess has a depth of 25 μm to 75 μm.

5. The battery device of claim 3, wherein the flat area is provided with at least one of the first depressions, and a total projected area of the first depressions at the flat area is 3% -30% of the flat area;

the bending region is provided with at least one second concave part, and the total projected area of the second concave part in the bending region accounts for 5% -50% of the bending region.

6. The battery device of claim 2, wherein the battery cell is a laminated battery cell, the battery cell comprises a plurality of stacked pole pieces, and at least some of the pole pieces are provided with the recess.

7. The battery device of claim 1, wherein the cell comprises a positive pole piece having the recess disposed thereon.

8. The battery device of claim 7, wherein the cell further comprises a negative electrode tab having the recess disposed thereon.

9. The battery device of claim 1, wherein the pole piece comprises a conductive layer and active material layers coated on both sides of the conductive layer;

the concave part is formed on the active material layer;

or, a pit is formed on the conductive layer, and the active material layer and the conductive layer are arranged along with the shape so as to form the concave part.

10. The battery device of claim 1, wherein a predetermined distance is provided between a location of the recess proximate the first edge of the pole piece and the first edge of the pole piece, the predetermined distance being greater than or equal to 5mm, the first edge of the pole piece being an edge of the pole piece proximate the pole post.