Outer film and battery
By setting a recessed structure and a position avoidance slot in the outer envelope of the soft-pack battery, the problem of angular interference during folding is solved, and higher packaging quality and operation simplicity is achieved.
Patent Information
- Application Number
- CN202420573601.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-03-22
- Publication Date
- 2025-04-01
- Estimated Expiration
- 2034-03-22
AI Technical Summary
During the folding process of the outer envelope film of the soft-pack battery, angular interference is prone to occur, affecting the packaging quality.
An outer envelope film is designed, which is provided with a recessed structure and a position avoiding groove in the edge sealing part, and these structures reserve a position avoiding space to reduce angular interference during folding.
It effectively reduces the chance of angular position interference during folding edges, simplifies packaging operations, and improves packaging quality.
Smart Images
Figure CN222705645U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of batteries, in particular to an outer envelope film and a battery. Background Art
[0002] In soft-pack batteries, the battery cells are encapsulated by outer film. The outer film needs to be trimmed and folded during the packaging of the battery cells. The outer film in the related art is prone to corner interference during folding, which affects the packaging. Therefore, it is necessary to study and improve the above problems. Utility Model Content
[0003] The utility model aims to solve at least one of the technical problems existing in the prior art. To this end, the utility model provides an outer film that can reduce the probability of angular interference during folding.
[0004] The utility model also provides a battery with the outer packaging film.
[0005] According to the outer packaging film of the embodiment of the utility model, the outer packaging film has a set thickness, and the outer packaging film includes a accommodating portion and a sealing portion, the accommodating portion is provided with a accommodating cavity, the accommodating cavity is used to accommodate the battery cell, the accommodating cavity defines a plurality of first corners on the accommodating portion, the accommodating portion is provided with a recessed structure, each of the recessed structures is sequentially distributed on the circumferential edge of the accommodating portion around the thickness direction of the outer packaging film, and the recessed structure is recessed toward the accommodating cavity in a direction perpendicular to the thickness direction, a plurality of the recessed structures are provided at the same first corner, adjacent recessed structures are spaced apart, and a first protrusion is defined between adjacent recessed structures. The edge sealing portion is connected to the circumferential outer edge of the accommodating portion, and the accommodating portion protrudes relative to the edge sealing portion along the thickness direction of the outer packaging film. The edge sealing portion is provided with a plurality of first avoidance grooves, and the first avoidance grooves penetrate the edge sealing portion along the thickness direction of the outer packaging film. The position of each of the first avoidance grooves corresponds one by one to the position of each of the recessed structures, and each of the first avoidance grooves is arranged at intervals.
[0006] The outer packaging film according to the embodiment of the utility model has at least the following beneficial effects: a recessed structure is arranged at the corner position of the accommodating portion and is recessed toward the accommodating cavity, so that an avoidance space can be reserved on the outer peripheral surface of the accommodating portion to realize the arrangement of a first avoidance groove on the edge sealing portion. The first avoidance groove makes the position of the edge sealing portion corresponding to the first corner no longer continuous. When the edge sealing portion is folded, the probability of interference at the corner position during folding can be effectively reduced. The folding operation can be completed by bending the portion of the edge sealing portion corresponding to the two side lines of the first corner and the portion of the edge sealing portion corresponding to the outer side of the first protrusion defined between the recessed structure.
[0007] According to some embodiments of the utility model, the projection of the recessed structure along the thickness direction of the outer membrane on a plane parallel to the edge sealing portion forms a first arc segment, and the projection of the first avoidance groove along the thickness direction of the outer membrane on a plane parallel to the edge sealing portion forms a second arc segment, and the first arc segment and the second arc segment are arranged with a common center.
[0008] According to some embodiments of the present invention, the first arc segment has a radius R1, the second arc segment has a radius R2, and the outer edge of the edge sealing portion in a direction perpendicular to the thickness of the outer film has a set distance D from the outer edge of the accommodating portion in a direction perpendicular to the thickness of the outer film, satisfying: R1-R2=D.
[0009] According to some embodiments of the utility model, the edge sealing portion is provided with a first pre-folding line and a second pre-folding line, the position of the first pre-folding line corresponds to the first corner where the recessed structure is provided, the first pre-folding line and the second pre-folding line are adjacently arranged in the circumferential direction of the accommodating portion, the extension line of the first pre-folding line intersects with the extension line of the second pre-folding line, and the intersection point of the extension line of the first pre-folding line and the extension line of the second pre-folding line is located in the first avoidance groove.
[0010] According to some embodiments of the present invention, a plurality of first protrusions are provided on the same first corner.
[0011] According to some embodiments of the present invention, a plurality of the first corners are respectively provided with the recessed structure.
[0012] The battery according to the embodiment of the utility model comprises a battery cell and an outer packaging film according to any one of the above embodiments, wherein the battery cell is arranged in the accommodating cavity.
[0013] The battery according to the embodiment of the utility model has at least the following beneficial effects: using the outer packaging film of the present application to cover the battery cell to form a battery can reduce the probability of corner interference during folding, facilitate packaging operations and ensure packaging quality.
[0014] According to some embodiments of the utility model, the battery cell has a set thickness, the battery cell includes multiple second corners, the battery cell is provided with multiple second avoidance grooves, each of the second avoidance grooves is distributed in sequence on the circumferential surface of the battery cell around the thickness direction of the battery cell, the same second corner is provided with multiple second avoidance grooves, adjacent second avoidance grooves are spaced apart, second protrusions are defined between adjacent second avoidance grooves, the position of the second avoidance grooves corresponds to the position of the recessed structure, and the position of the second protrusion corresponds to the position of the first protrusion.
[0015] According to some embodiments of the utility model, the battery includes a pole ear, which is connected to the battery cell, and the pole ear is located on one side of the battery cell perpendicular to the thickness direction, and the recessed structure is provided at at least one of the first corners on the opposite side of the pole ear relative to the battery cell.
[0016] According to some embodiments of the present invention, the battery cell includes pole pieces, each of the pole pieces is stacked in sequence along the thickness direction of the battery cell, and the second avoidance groove extends to each of the pole pieces.
[0017] Additional aspects and advantages of the present invention will be given in part in the following description, and in part will become apparent from the following description, or will be learned through the practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS
[0018] The present invention is further described below with reference to the accompanying drawings and embodiments, wherein:
[0019] Figure 1 This is a schematic diagram of an outer envelope of an embodiment of the utility model in an unfolded state;
[0020] Figure 2 A schematic diagram of a battery according to an embodiment of the present utility model;
[0021] Figure 3 for Figure 2 A front view of
[0022] Figure 4 A schematic diagram of a battery cell in a battery according to an embodiment of the present utility model;
[0023] Figure 5 Schematic diagram of the outer envelope membrane of the related art.
[0024] Reference numerals:
[0025] Battery 10;
[0026] Outer envelope 100, third pre-folding line 110;
[0027] The accommodating portion 200, the first corner 210, the accommodating cavity 220, the recessed structure 230, the first arc segment 231, and the first protruding portion 240;
[0028] The edge sealing portion 300, the first avoidance groove 310, the second arc segment 311, the first pre-folding line 320, and the second pre-folding line 330;
[0029] The battery cell 400, the tab 410, the second corner 420, the second avoidance groove 430, and the second protrusion 440;
[0030] Outer envelope 500 , lower side 510 , right side 520 , and corner interference structure 530 . DETAILED DESCRIPTION
[0031] The embodiments of the present invention are described in detail below, and examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the present invention, and cannot be understood as limiting the present invention.
[0032] In the description of the present invention, it should be understood that descriptions involving orientation, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.
[0033] In the description of the present utility model, "several" means more than one, "many" means more than two, "greater than", "less than", "exceed" etc. are understood to exclude the number itself, and "above", "below", "within" etc. are understood to include the number itself. If there is a description of "first" or "second", it is only used to distinguish the technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the order of the indicated technical features.
[0034] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.
[0035] In the description of the utility model, the description with reference to the terms "one embodiment", "some embodiments", "illustrative embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the utility model. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.
[0036] Reference Figure 5 When the outer film 500 in the related art is folded, after the lower side 510 and the right side 520 are bent, a V-shaped corner interference structure 530 will appear at the corner. The existence of the corner interference structure 530 affects the overall packaging and reduces the overall energy density of the battery 10. Figure 2The present application provides a recessed structure 230 in the accommodating portion 200 of the outer membrane 100, utilizes the recessed structure 230 for avoidance, and provides a first avoidance groove 310 in the edge sealing portion 300 to change the shape of the corner position of the edge sealing portion 300, thereby effectively reducing the possibility of interference at the corner position after the edge sealing portion 300 is bent.
[0037] The outer envelope and battery of the embodiment of the present application are described below with reference to the drawings of the specification. It should be noted that the thickness direction is shown in the front-to-back direction in the drawings. It should be noted that Figure 3 The outer film 100 is in a state of covering the battery cell 400 and completing the folding.
[0038] Reference Figures 1 to 3 According to the outer film 100 of the embodiment of the utility model, the outer film 100 has a set thickness, and the outer film 100 includes a receiving portion 200 and an edge sealing portion 300. The receiving portion 200 is provided with a receiving cavity 220, and the receiving cavity 220 is used to receive the battery cell 400. The receiving cavity 220 defines a plurality of first corners 210 on the receiving portion 200. The receiving portion 200 is provided with a recessed structure 230. Each recessed structure 230 is sequentially distributed on the circumferential edge of the receiving portion 200 in the thickness direction of the outer film 100, and the recessed structure 230 is recessed toward the receiving cavity 220 in a direction perpendicular to the thickness direction. The first corner 210 is provided with a plurality of recessed structures 230, adjacent recessed structures 230 are arranged at intervals, and a first protruding portion 240 is defined between adjacent recessed structures 230; the edge sealing portion 300 is connected to the circumferential outer edge of the accommodating portion 200, and the accommodating portion 200 protrudes relative to the edge sealing portion 300 along the thickness direction of the outer film 100, and the edge sealing portion 300 is provided with a plurality of first avoidance grooves 310, and the first avoidance grooves 310 penetrate the edge sealing portion 300 along the thickness direction of the outer film 100, and the positions of the first avoidance grooves 310 correspond one by one to the positions of the recessed structures 230, and the first avoidance grooves 310 are arranged at intervals.
[0039] A recessed structure 230 is provided at the corner position of the accommodating portion 200, which is recessed toward the accommodating cavity 220, so that an avoidance space can be reserved on the outer peripheral surface of the accommodating portion 200 to realize the provision of a first avoidance groove 310 on the edge sealing portion 300. The first avoidance groove 310 makes the position of the edge sealing portion 300 corresponding to the first corner 210 no longer continuous. When the edge sealing portion 300 is folded, the probability of interference at the corner position during folding can be effectively reduced. The folding operation can be completed by bending the portion of the edge sealing portion 300 corresponding to the two side lines of the first corner 210 and the portion of the edge sealing portion 300 corresponding to the outer side of the first protrusion 240 defined between the recessed structure 230.
[0040] Reference Figure 2 and Figure 3The projection of the recessed structure 230 along the thickness direction of the outer film 100 on a plane parallel to the edge sealing portion 300 forms a first arc segment 231, and the projection of the first avoidance groove 310 along the thickness direction of the outer film 100 on a plane parallel to the edge sealing portion 300 forms a second arc segment 311. The first arc segment 231 and the second arc segment 311 are arranged cocentrically. The first avoidance groove 310 is formed into an arc shape, which can make the folded edge of the edge sealing portion 300 excessively smooth, so as to further reduce the probability of folding interference at the corners. The recessed structure 230 is recessed into an arc shape, which can ensure that the formed avoidance space is adapted to the shape of the first avoidance groove 310, thereby ensuring avoidance. Among them, the arc shape is easy to process, which can be achieved by a punch head with an arc.
[0041] Reference Figure 3 Further, the first arc segment 231 has a radius R1, the second arc segment 311 has a radius R2, and the outer edge of the edge sealing portion 300 in the direction perpendicular to the thickness of the outer film 100 and the outer edge of the accommodating portion 200 in the direction perpendicular to the thickness of the outer film 100 have a set spacing D, satisfying: R1-R2=D. By controlling R1-R2=D, it can be ensured that after the folding operation is completed, the unfolded margins at other positions of the edge sealing portion 300 are the same as the spacing between the edge of the first avoidance groove 310 and the edge of the recessed structure 230, so that the folding of the edge sealing portion 300 is uniform after completion, which is convenient for the subsequent assembly of the battery 10. It can be understood that after the edge sealing portion 300 is folded, the bent part may be upright or may be inclined toward the accommodating portion 200 and attached to the accommodating portion 200. The outer edge of the edge sealing portion 300 in the thickness direction perpendicular to the outer film 100 is actually the outer edge of the projection of the edge sealing portion 300 formed along the thickness direction on the surface parallel to the edge sealing portion 300, that is, it should be the fold line position where the edge sealing portion 300 is bent.
[0042] Reference Figure 3In some embodiments, the edge sealing part 300 is provided with a first pre-folding line 320 and a second pre-folding line 330. The position of the first pre-folding line 320 corresponds to the first corner 210 provided with the recessed structure 230. The first pre-folding line 320 and the second pre-folding line 330 are adjacently arranged in the circumferential direction of the accommodating part 200. The extension line of the first pre-folding line 320 intersects with the extension line of the second pre-folding line 330. The intersection point of the extension line of the first pre-folding line 320 and the extension line of the second pre-folding line 330 is located in the first avoidance groove 310. When the edge sealing part 300 is folded, it is folded according to the pre-divided pre-folding lines, wherein the first pre-folding line 320 is used to fold the portion of the edge sealing part 300 corresponding to the outer side of the recessed structure 230 away from the accommodating cavity 220, and the second pre-folding line 330 is used to fold the edge sealing part 300 corresponding to the edge line of the first corner 210. It can be understood that the right two edges of the first corner 210 are defined. The first pre-folding line 320 and the second pre-folding line 330 are adjacent to each other, and the probability of folding interference between the partial edge sealing portion 300 bent by the first pre-folding line 320 and the partial edge sealing portion 300 bent by the second pre-folding line 330 is relatively high. By controlling the intersection point of the extension line of the first pre-folding line 320 and the extension line of the second pre-folding line 330 to be located within the first avoidance groove 310, it is possible to ensure that the avoidance effect of the first avoidance groove 310 is effective and reduce the probability of folding interference.
[0043] The two ends of the first pre-folding line 320 extend into two adjacent first avoidance grooves 310 to reduce the probability of edge interference when the portion of the edge sealing portion 300 corresponding to the position of the recessed structure 230 is bent.
[0044] Reference Figure 3 In some embodiments, a plurality of first protrusions 240 are formed on the same first corner 210, that is, more than three recessed structures 230 are provided at the same first corner 210, and more than three first avoidance grooves 310 are provided correspondingly. As the number of first avoidance grooves 310 increases, the shape of the corresponding first corner 210 can be closer to an arc shape, and the size of each first avoidance groove 310 can also be reduced accordingly, for example,
[0045] In an embodiment where the first avoidance groove 310 is formed in an arc shape, the radius R2 of the second arc segment 311 formed by the first avoidance groove 310 can be set to be smaller, so the area where the edge sealing portion 300 needs to be trimmed and removed will also be reduced. The outer film 100 can reserve a larger space for the accommodating cavity 220 to improve the overall energy density of the battery 10.
[0046] Reference Figure 3In some embodiments, a plurality of first corners 210 are respectively provided with a recessed structure 230 so as to form a avoidance structure at each of the plurality of first corners 210 , which can reduce the interference of the folded edge in different packaging methods of the outer film 100 .
[0047] Specifically, refer to Figure 1 In some embodiments, the outer film 100 is an integrated film, and the outer film 100 is provided with a third pre-folding line 110, and the third pre-folding line 110 divides the outer film 100 into two opposite areas, for example, Figure 1 The left area is provided with a receiving cavity 220. After the battery cell 400 is placed, it is folded along the third pre-folding line 110 so that part of the right area covers the receiving cavity 220. Alternatively, Figure 1 The left and right areas are provided with symmetrical accommodating cavities 220 with the third pre-folding line 110 as the axis of symmetry, and are folded along the third pre-folding line 110 so that the two accommodating cavities 220 are opposite to each other to define a complete accommodating cavity. By folding the third pre-folding line 110, single-sided packaging can be achieved, and subsequent cutting and folding operations can be reduced, and the energy density can be increased, and the drop safety of the battery 10 can be improved. Among them, since only single-sided packaging is required, it is only necessary to provide a recessed structure 230 at the first corner 210 on the side away from the third pre-folding line 110, and a conventional top sealing operation is usually performed on the side of the battery cell 400 where the pole ear 410 is provided, so there will be no corner interference problem.
[0048] In other embodiments, the outer membrane 100 is a split membrane, that is, the outer membrane 100 is formed by relatively attaching and connecting two membranes. This method requires sealing the bottom edge and both side edges. Therefore, recessed structures 230 can be provided at the corners defined by the bottom edge and both side edges to reduce the probability of corner interference.
[0049] It can be understood that the side of the battery cell 400 provided with the pole ear 410 is defined as the top side, the side away from the pole ear 410 is defined as the bottom side, and the two sides perpendicular to the top side toward the bottom side are the side edges. In the accompanying drawings, the top side and the bottom side are respectively displayed in the up and down directions, and the two side edges are displayed in the left and right directions.
[0050] Reference Figures 2 to 4 According to the battery 10 of the embodiment of the utility model, the battery 10 comprises a battery cell 400 and an outer film 100 of any of the above embodiments, and the battery cell 400 is disposed in the accommodating cavity 220. The outer film 100 of the present application is used to cover the battery cell 400 to form the battery 10, which can reduce the probability of corner interference during folding, facilitate packaging operation and ensure packaging quality.
[0051] Reference Figure 3 and Figure 4In some embodiments, the battery 10 includes a tab 410, which is connected to the battery cell 400. The tab 410 is located on one side of the battery cell 400 perpendicular to the thickness direction, and a recessed structure 230 is provided at at least one first corner 210 on the opposite side of the tab 410 relative to the battery cell 400. Conventional top sealing operations are usually performed on the side of the battery cell 400 where the tab 410 is provided, and therefore, the recessed structure 230 is provided at the first corner 210 on the side opposite to the tab 410, so that the first avoidance groove 310 is provided accordingly.
[0052] Reference Figure 4 In some embodiments, the battery cell 400 has a set thickness, the battery cell 400 includes a plurality of second corners 420, and the battery cell 400 is provided with a plurality of second avoidance grooves 430, each second avoidance groove 430 is sequentially distributed on the circumferential surface of the battery cell 400 around the thickness direction of the battery cell 400, and the same second corner 420 is provided with a plurality of second avoidance grooves 430, and adjacent second avoidance grooves 430 are arranged at intervals, and a second protrusion 440 is defined between adjacent second avoidance grooves 430. Among them, the position of the second avoidance groove 430 corresponds to the position of the recessed structure 230, and the position of the second protrusion 440 corresponds to the position of the first protrusion 240, so as to realize the contour setting of the battery cell 400 and the accommodating cavity 220, improve the utilization rate of the accommodating cavity 220, and improve the energy density of the battery 10.
[0053] In some embodiments, the battery cell 400 includes pole pieces, each of which is stacked in sequence along the thickness direction of the battery cell 400, and the second avoidance groove 430 extends to each pole piece. In the embodiment where the battery cell 400 needs to be configured to be in a conformal manner with the accommodating cavity 220, the shape of the battery cell 400 is relatively complex, and a plurality of pole pieces are stacked to form a laminated battery cell 400. It is only necessary to provide corresponding slots on each pole piece, and the second avoidance groove 430 can be formed after each pole piece is stacked, and the preparation difficulty of the battery cell 400 is low.
[0054] The embodiments of the utility model are described in detail above in conjunction with the accompanying drawings, but the utility model is not limited to the above embodiments. Various changes can be made within the knowledge of ordinary technicians in the relevant technical field without departing from the purpose of the utility model. In addition, the embodiments of the utility model and the features in the embodiments can be combined with each other without conflict.
Claims
1. An outer envelope, characterized in that: The outer envelope has a set thickness, and the outer envelope comprises: An accommodating portion is provided with an accommodating cavity, the accommodating cavity is used to accommodate the battery cell, the accommodating cavity defines a plurality of first corners on the accommodating portion, the accommodating portion is provided with a recessed structure, each of the recessed structures is sequentially distributed on the circumferential edge of the accommodating portion around the thickness direction of the outer envelope, and the recessed structure is recessed toward the accommodating cavity in a direction perpendicular to the thickness direction, a plurality of the recessed structures are provided at the same first corner, adjacent recessed structures are arranged at intervals, and a first convex portion is defined between adjacent recessed structures; An edge sealing portion, wherein the edge sealing portion is connected to the circumferential outer edge of the accommodating portion, the accommodating portion protrudes relative to the edge sealing portion along the thickness direction of the outer packaging film, the edge sealing portion is provided with a plurality of first avoidance grooves, the first avoidance grooves penetrate the edge sealing portion along the thickness direction of the outer packaging film, the position of each of the first avoidance grooves corresponds one by one to the position of each of the recessed structures, and each of the first avoidance grooves is arranged at intervals.
2. The outer envelope according to claim 1, characterized in that: The projection of the recessed structure along the thickness direction of the outer membrane on a plane parallel to the edge sealing portion forms a first arc segment, and the projection of the first avoidance groove along the thickness direction of the outer membrane on a plane parallel to the edge sealing portion forms a second arc segment. The first arc segment and the second arc segment are arranged with the same center.
3. The outer envelope according to claim 2, characterized in that: The first arc segment has a radius R1, the second arc segment has a radius R2, and the outer edge of the edge sealing portion in a direction perpendicular to the thickness of the outer film has a set distance D from the outer edge of the accommodating portion in a direction perpendicular to the thickness of the outer film, satisfying: R1-R2=D.
4. The outer envelope according to claim 2, characterized in that: The edge sealing portion is provided with a first pre-folding line and a second pre-folding line, the position of the first pre-folding line corresponds to the first corner where the recessed structure is provided, the first pre-folding line and the second pre-folding line are adjacently arranged in the circumferential direction of the accommodating portion, the extension line of the first pre-folding line intersects with the extension line of the second pre-folding line, and the intersection point of the extension line of the first pre-folding line and the extension line of the second pre-folding line is located in the first avoidance groove.
5. The outer envelope according to claim 1, characterized in that: A plurality of first protrusions are disposed on the same first corner.
6. The outer envelope according to claim 1, characterized in that: The recessed structures are respectively disposed at a plurality of the first corners.
7. A battery, characterized in that include: The outer envelope according to any one of claims 1 to 6; The battery cell is arranged in the accommodating cavity.
8. The battery according to claim 7, characterized in that The battery cell has a set thickness, the battery cell includes multiple second corners, the battery cell is provided with multiple second avoidance grooves, each of the second avoidance grooves is distributed in sequence on the circumferential surface of the battery cell around the thickness direction of the battery cell, the same second corner is provided with multiple second avoidance grooves, adjacent second avoidance grooves are spaced apart, second protrusions are defined between adjacent second avoidance grooves, the position of the second avoidance grooves corresponds to the position of the recessed structure, and the position of the second protrusion corresponds to the position of the first protrusion.
9. The battery according to claim 8, characterized in that The battery cell comprises pole pieces, each of which is stacked in sequence along a thickness direction of the battery cell, and the second avoidance groove extends to each of the pole pieces.
10. The battery according to claim 7, characterized in that It includes a pole ear connected to the battery cell, the pole ear is located on one side of the battery cell perpendicular to the thickness direction, and the recessed structure is provided at at least one of the first corners on the opposite side of the pole ear relative to the battery cell.