CN220138497U - Single battery and battery pack - Google Patents

Abstract

The utility model discloses a single battery and a battery pack, wherein the single battery comprises a battery core, a shell, a top cover plate, a pole and a bus bar, the battery core is accommodated in the shell, the top cover plate is covered and sealed at the top of the shell, the pole is arranged on the top cover plate, and the bus bar is electrically connected with the pole; the battery pack comprises a plurality of single batteries. According to the utility model, the single battery is provided with the bus bar, the bus bar is electrically connected with the pole, in the battery pack assembly process, the bus bar does not need to be welded with the pole in the same single battery, and the serial/parallel connection of the adjacent single batteries can be realized by directly connecting the bus bar with the pole or the bus bar in another single battery, so that the welding times of the bus bar in the battery pack assembly process and welding slag formed in the welding process are reduced, and the use risk of the battery pack is reduced.

Description

Single battery and battery pack

Technical Field

The utility model relates to the technical field of energy storage devices, in particular to a single battery and a battery pack.

Background

The battery package of the power battery system is generally integrated with a certain number of single batteries in a box body, the batteries form a power supply loop through series-parallel connection, in the related art, after the single batteries are assembled into the box body, a busbar is connected with a battery pole in a laser welding mode, and metal welding slag can be inevitably generated in the laser welding process and splashed into the box body or the battery system, so that insulation faults of the battery system, even short circuits and fires occur, and the safety risk is high.

Disclosure of Invention

The present utility model aims to solve at least one of the technical problems existing in the prior art. Therefore, the utility model provides a single battery, which can reduce the welding quantity of battery poles and bus bars, reduce welding slag and reduce the use risk of a battery system.

The utility model also provides a battery pack with the single battery.

An embodiment of a single cell according to a first aspect of the present utility model includes:

a battery cell;

the battery cell is accommodated in the shell;

a top cover plate, which is covered and sealed at the top of the shell;

the pole is arranged on the top cover plate;

and the bus is electrically connected with the pole.

The single battery provided by the embodiment of the utility model has at least the following beneficial effects:

according to the utility model, the single battery is provided with the bus bar, the bus bar is electrically connected with the pole, in the battery pack assembly process, the bus bar does not need to be welded with the pole in the same single battery, and the serial/parallel connection of the adjacent single batteries can be realized by directly connecting the bus bar with the pole or the bus bar in another single battery, so that the welding times of the bus bar in the battery pack assembly process and welding slag formed in the welding process are reduced, and the use risk of the battery pack is reduced.

According to some embodiments of the utility model, the busbar is connected with the pole as an integrally formed structure.

According to some embodiments of the utility model, the single cell comprises at least two of the poles, and wherein the bus bars are connected to both of the poles;

wherein the two bus bars extend in opposite directions;

alternatively, the two bus bars respectively extend out from two adjacent side surfaces of the housing.

According to some embodiments of the utility model, the top of the top cover plate has a protruding support portion located at an edge of the top cover plate, the support portion being in contact with the bottom surface of the busbar.

According to some embodiments of the utility model, the busbar comprises a first connecting portion and a second connecting portion connected to each other, and the first connecting portion and the second connecting portion are respectively used for connecting the poles of different single batteries.

According to some embodiments of the utility model, a portion of the busbar arches towards or away from the housing to form a buffer portion, and the first connection portion and the second connection portion are respectively connected to opposite sides of the buffer portion.

According to some embodiments of the utility model, the bus bar and the pole are respectively provided with two, the bus bar is provided with a first connecting part and a second connecting part which are connected, the first connecting parts of the two bus bars are respectively connected with the two pole, and the second connecting parts are used for connecting the second connecting parts of the bus bars in the other single battery.

According to some embodiments of the utility model, the second connecting portion of one of the bus bars is bent downward with respect to the first connecting portion, and the second connecting portion is used for overlapping with the second connecting portion of the bus bar in the other of the unit cells.

According to some embodiments of the utility model, the second connection portion is configured to overlap with the second connection portion of the bus bar in another of the unit cells, and an upper surface of the first connection portion of the bus bar connected to each other is flush.

A battery pack according to an embodiment of the second aspect of the present utility model includes:

a plurality of unit cells of the embodiment of the first aspect;

the battery cell is arranged in the box body, the battery cells are at least distributed along a first direction, and the pole posts of adjacent battery cells are connected through at least one busbar.

Additional aspects and advantages of the utility model will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the utility model.

Drawings

The utility model is further described with reference to the accompanying drawings and examples, in which:

FIG. 1 is a schematic diagram of an embodiment of a cell of the present utility model;

FIG. 2 is a schematic diagram of another embodiment of a cell according to the present utility model;

FIG. 3 is a schematic view of the bus bar and pole of FIG. 2 after being disassembled;

FIG. 4 is a schematic diagram of the connection of the single cells in FIG. 1;

FIG. 5 is a schematic diagram of another embodiment of a cell according to the present utility model;

FIG. 6 is a schematic diagram of the connection of the single cells in FIG. 2;

FIG. 7 is a schematic view of one embodiment of an arrangement of unit cells within a battery pack;

fig. 8 is a schematic view of another embodiment of an arrangement state of unit cells in a battery pack;

fig. 9 is a schematic view of other embodiments of arrangement states of unit cells in a battery pack;

fig. 10 is a schematic view of an embodiment of a battery pack of the present utility model.

Reference numerals:

the battery pack comprises a single battery 100, a housing 110, a top cover plate 120, a pole 130, a second positioning part 131, a busbar 140, a first positioning part 141, a first connecting part 142, a second connecting part 143, a buffer part 144 and a supporting part 150;

and a case 200.

Detailed Description

Embodiments of the present utility model are described in detail below, examples of which are illustrated in the accompanying drawings, wherein like or similar reference numerals refer to like or similar elements or elements having like or similar functions throughout. The embodiments described below by referring to the drawings are illustrative only and are not to be construed as limiting the utility model.

In the description of the present utility model, it should be understood that references to orientation descriptions such as upper, lower, front, rear, left, right, etc. are based on the orientation or positional relationship shown in the drawings, are merely for convenience of description of the present utility model and to simplify the description, and do not indicate or imply that the apparatus or elements referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus should not be construed as limiting the present utility model.

In the description of the present utility model, the meaning of a number is one or more, the meaning of a number is two or more, and greater than, less than, exceeding, etc. are understood to exclude the present number, and the meaning of a number is understood to include the present number. The description of the first and second is for the purpose of distinguishing between technical features only and should not be construed as indicating or implying relative importance or implicitly indicating the number of technical features indicated or implicitly indicating the precedence of the technical features indicated.

In the description of the present utility model, unless explicitly defined otherwise, terms such as arrangement, installation, connection, etc. should be construed broadly and the specific meaning of the terms in the present utility model can be reasonably determined by a person skilled in the art in combination with the specific contents of the technical scheme.

In the description of the present utility model, the descriptions of the terms "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples," etc., mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the present utility model. In this specification, schematic representations of the above terms do not necessarily refer to the same embodiments or examples. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

In the embodiment of the utility model, as shown in fig. 1 to 3, a single battery 100 is provided, wherein the single battery 100 includes a battery cell, a housing 110 and a top cover plate 120, the housing 110 is provided with one, a cavity is provided in the housing 110 for placing the battery cell, and the top cover plate 120 is covered on the top of the housing 110 to seal the battery cell in the housing 110; the unit cell 100 further includes a post 130 and a bus bar 140, wherein the post 130 is mounted on the top of the top cover 120, and the bus bar 140 is electrically connected to the post 130.

In the related art, in the assembly process of the battery pack, the single battery placed in the box 200 needs to be connected with the post of the adjacent single battery through a welding mode, so that the single battery forms a serial/parallel loop, and welding slag formed in the welding process remains in the box 200 or on the surface of the single battery, so that the welding slag cannot be cleaned, and the use safety in the later stage of the battery pack is directly affected. According to the utility model, the single battery 100 is provided with the bus bar 140, the bus bar 140 is electrically connected with the pole 130, and in the battery pack assembly process, the bus bar 140 does not need to be welded with the pole 130 in the same single battery 100, and the serial/parallel connection of the adjacent single batteries 100 can be realized by directly connecting the bus bar 140 with the pole 130 or the bus bar 130 in another single battery 100, so that the welding times of the bus bar 140 in the battery pack assembly process and welding slag formed in the welding process are reduced, and the use risk of the battery pack is reduced.

It can be appreciated that the unit cells 100 may be cylindrical cells, square cells, etc., and each unit cell 100 is provided with at least one pole 130, and the bus bar 140 is connected to at least one pole 130.

It should be noted that, in the present utility model, the connection manner between the post 130 and the busbar 140 in the same single battery 100 may be that the post 130 and the busbar 140 are assembled or integrally formed in advance, and the post 130, the busbar 140 and the top cover 120 are assembled to the housing 110 to form the single battery 100; alternatively, after the post 130, the bus bar 140, and the top cover 120 are assembled to the housing 110, the bus bar 140 is connected to the post 130 by welding, detachable connection, or the like, to form the unit cell 100.

In some embodiments, the bus bar 140 and the pole 130 are connected into an integrally formed structure, the bus bar 140 and the pole 130 are integrally assembled with other components in the single battery 100, the bus bar 140 and the pole 130 do not need to be additionally assembled, the processing efficiency of the single battery 100 can be improved, the bus bar 140 and the pole 130 are connected with each other in the forming process of the single battery 100, the bus bar 140 and the pole 130 do not need to be welded in the forming process of the single battery 100, and welding slag formed in the assembling process of the battery pack is further reduced. Specifically, the busbar 140 and the post 130 may be formed into an integral structure by casting, injection molding, stamping, or the like.

Further, the bus bar 140 has a first positioning portion 141, the top of the pole 130 has a second positioning portion 131, the centers of the first positioning portion 141 and the second positioning portion 131 are aligned in the height direction of the housing 110, and the first positioning portion 141 and the second positioning portion 131 cooperate with each other, so that the bus bar 140 and the pole 130 can be precisely aligned and welded. The second positioning part 131 is arranged as a pit positioned on the top surface of the pole 130, the pit is formed by downwards sinking part of the top surface of the pole 130, the first positioning part 141 is arranged as a through hole penetrating through the bus bar 140, when the first positioning part 141 is aligned with the second positioning part 131, the pit is centered with the through hole, and in the welding process of the bus bar 140 and the pole 130, the positions of the pit and the through hole are shot through a visual detection module and are subjected to image processing, so that whether the pit and the through hole are aligned is obtained, and the welding precision of the bus bar 140 and the pole 130 is ensured; alternatively, the second positioning portion 131 is provided as a protrusion protruding from the top surface of the post, and the first positioning portion 141 is provided as a through hole penetrating the bus bar 140, and when the first positioning portion 141 is aligned with the second positioning portion 131, the protrusion is inserted into and centered with the through hole; or, the second positioning portion 131 is arranged as a pit located on the top surface of the pole 130, the first positioning portion 141 is arranged as a protrusion located on the bottom of the busbar 140, and the protrusion can be inserted into the pit to achieve mutual limitation of the busbar 140 and the pole 130, so that the busbar and the pole 130 can be accurately welded.

In addition, the top of the top cover plate 120 is provided with a supporting portion 150 protruding, the supporting portion 150 is located at the edge of the top cover plate 120, the supporting portion 150 contacts with the bottom surface of the busbar 140 and is used for supporting the busbar 140, deformation affecting welding quality due to the pressure of a welding tool in the welding process of the busbar 140 is avoided, and the busbar 140 is insulated from the top cover plate 120, so that short circuit and fire are avoided. The support 150 may be fixed to the top of the top cover 120 by welding, soldering, and the support 150 is made of an insulating material such as ceramic, plastic, etc.

In one embodiment, the bus bar 140 includes a first connection portion 142 and a second connection portion 143 that are connected, where the first connection portion 142 and the second connection portion 143 are respectively used to connect the poles 130 of different unit batteries 100, that is, the bus bar 140 in one unit battery 100 may connect the poles 130 in different unit batteries 100, so as to implement serial/parallel connection of two unit batteries 100.

Referring to fig. 1 and 4, taking the cell 100 shown in fig. 1 as an example, when two cells 100 are connected in series/parallel, the cell 100 on the right side has a bus bar 140, a first connection portion 142 of the bus bar 140 is connected to the post 130, and a second connection portion 143 of the bus bar 140 is connected to the post 130 of the cell 100 on the left side, so as to realize the series/parallel connection of the two cells 100. Alternatively, as shown in fig. 5, the single battery 100 includes two poles 130 and two buses 140, wherein the first connection portion 142 of each bus 140 is connected to one pole 130, and the two buses 140 are oriented differently, so that the single battery 100 of the present utility model can be used in combination with the single battery 100 in the prior art, and form a serial/parallel circuit; that is, the battery cell 100 of the present utility model has two bus bars 140, and the second connection portions 143 of the two bus bars 140 are respectively connected to the poles 130 of the two battery cells 100 located at both sides of the battery cell 100, so that the battery cell 100 of the present utility model and the battery cell of the prior art are connected to each other, which is advantageous for popularization and use of the battery cell 100 of the present utility model.

It should be noted that, two poles 130 are disposed in the single battery 100, and the two poles 130 are symmetrical with respect to the center of the top cover 120, so that after the single battery 100 rotates 180 °, the bus bars 140 can be aligned with and connected to other single batteries 100, and the single battery 100 is flexible to assemble and use.

Further, the partial bus bars 140 arch towards the battery core or away from the battery core to form the buffer portion 144, and the first connecting portion 142 and the second connecting portion 143 are respectively connected to two opposite sides of the buffer portion 144, so as to buffer the bulge of the single battery 100 in the use process, and avoid excessive deformation of the single battery 100.

In another embodiment, referring to fig. 2 and 6, the single battery 100 includes two buses 140 and two poles 130, each bus 140 is connected with one pole 130, and different single batteries 100 are connected in series/parallel through the interconnection between the buses 140; specifically, the bus bar 140 has a first connecting portion 142 and a second connecting portion 143 connected to each other, the first connecting portion 142 of the bus bar 140 is connected to the post 130 in the same single cell 100, and the second connecting portion 143 is used for connecting the second connecting portion 143 of the bus bar 140 in another single cell 100, so as to realize interconnection of the two single cells 100.

In one embodiment, in two buses 140 located in the same single battery 100, the second connection portion 143 of one bus 140 is bent downward relative to the first connection portion 142, and the second connection portion 143 is used for being connected to the second connection portion 143 of the bus 140 in the other single battery 100 in a lap joint manner; because the second connecting portion 143 sinks relative to the first connecting portion 142, after the two second connecting portions 143 located in different single batteries 100 overlap each other, a relatively flat contact plane is provided, so that the two connecting portions are convenient to weld, the welding strength of the two bus bars 140 can be improved, and the bulge of the single battery 100 in the later use process can be buffered.

It should be noted that, the supporting portion 150 is located below the second connecting portion 143 and supports the second connecting portion 143, and since the second connecting portion 143 is bent downward relative to the first connecting portion 142, the thickness of the supporting portion 150 in the vertical direction can be reduced, and the protruding height of the two second connecting portions 143 relative to the top surface of the first connecting portion 142 after overlapping is reduced, so that the appearance of the single battery 100 after being put into the box is more concise. In addition, the second connection portion 143 in the other single battery 100 overlapped with the second connection portion 143 can compensate for the sinking height of the second connection portion 143, when the sinking height of the second connection portion 143 is equal to the thickness of the second connection portion 143, the upper surfaces of the first connection portions 142 of the two mutually welded buses 140 are flush, so that the flatness of the assembled surface of the single battery 100 is further improved; in addition, by overlapping the two bus bars 140, the upper planes of the two bus bars 140 can be kept flush, so that the flatness of the upper planes of the assembled single batteries 100 is better, and the upper surfaces of the bus bars 140 are the upper surfaces which are not shielded and are in a bare state; in this case, in the two buses 140 located in the same single battery 100, only the second connection portion 143 of one of the buses 140 needs to be sunk, so that the upper planes of the buses 140 are kept flush after the buses are overlapped with each other.

In other embodiments, the second connection portion 143 is thinned, and a groove is formed at the top of the second connection portion 143, when the second connection portions 143 of two different unit cells 100 overlap each other, the second connection portion 143 of the busbar 140 in another unit cell 100 is placed in the groove from top to bottom, so that the upper surfaces of the two second connection portions 143 are flush; or, in two buses 140 located in the same single battery 100, a groove is formed at the bottom of the second connection portion 143 of one bus 140, a groove is formed at the top of the second connection portion 143 of the other bus 140, after the second connection portions 143 of two different single batteries 100 overlap each other, the thickness of the two second connection portions 143 is equal to the thickness of the first connection portion 142, so that on one hand, welding is facilitated to the two second connection portions 143, and on the other hand, the upper surfaces of the two buses 140 welded to each other can be kept flush.

In some embodiments, the single battery 100 includes at least two poles 130, and the two poles 130 are connected with the bus bars 140, and the two bus bars 140 are respectively used for connecting with the poles 130 or the bus bars 140 in the other single batteries 100; because at least two buses 140 are arranged in the single battery 100, in the battery pack assembly process, the single battery 100 can realize serial/parallel connection between the single batteries 100 only by connecting the buses in the single battery 100 with the poles or buses in other single batteries 100 without carrying out the welding operation of the buses and the poles, the operation is more convenient, and different single batteries 100 can be flexibly installed.

Further, two bus bars 140 located in the same single battery 100 extend in opposite directions, and the two bus bars 140 may be electrically connected to other single batteries 100 located at two opposite sides of the single battery 100. For example, referring to fig. 7 and 8, the unit cells 100 are configured as square cells, the unit cells 100 are arranged in the box body of the battery pack along the direction perpendicular to the large surface, and two bus bars 140 in the unit cells 100 extend perpendicular to the large surface and have opposite extending directions, so that the two bus bars 140 can be respectively connected with other unit cells 100 located at two sides of the unit cells 100; or, the unit cells 100 are arranged as square cells, the unit cells 100 are arranged in the box body of the battery pack along the direction perpendicular to the small surface, and the two bus bars 140 in the unit cells 100 extend perpendicular to the small surface and have opposite extending directions, so that the two bus bars 140 can be respectively connected with other unit cells 100 positioned at two sides of the unit cells 100.

Further, the two poles 130 and the two bus bars 140 are symmetrical with respect to the center of the top cover 120, so that after the single battery 100 rotates 180 °, the two bus bars 140 can be still connected with the bus bars 140 in the other single batteries 100, and the single battery 100 is flexible to assemble and use.

Alternatively, referring to fig. 9, two bus bars 140 located in the same unit cell 100 protrude respectively toward two sides adjacent to the case 110, and the two bus bars 140 can be connected to other unit cells 100 located on the adjacent sides of the unit cell 100, respectively. Taking square batteries as an example, the single battery 100 extends in the case of the battery pack perpendicularly to the large surface and the small surface at the same time, one of the bus bars 140 extends perpendicularly to the large surface so as to be connected with other single batteries 100 arranged on the side of the single battery 100 in the direction perpendicular to the large surface, and the other bus bar 140 extends perpendicularly to the small surface so as to be connected with other single batteries 100 arranged on the side of the single battery 100 in the direction perpendicular to the small surface.

Referring to fig. 7 and 8, the plurality of unit cells 100 are arranged at least along the first direction, the poles 130 of adjacent unit cells 100 are connected by at least one bus bar 140, and all unit cells 100 form a series/parallel circuit by the connection of the bus bars 140.

As shown in fig. 7, taking the unit cell 100 in fig. 1 as an example, in the adjacent unit cells 100, the second connection portion 143 of the busbar 140 connected to one unit cell 100 is welded to the post 130 of the other unit cell 100, and since the first connection portion 142 of the busbar 140 is already connected to the post 130, after the second connection portion 143 is welded to the post 130, the electrical connection of the adjacent unit cell 100 is achieved, and the welding of the plurality of post 130 and the second connection portion 143 is repeated, so that the plurality of unit cells 100 are connected to form a serial-parallel loop. As shown in fig. 8, taking the unit battery 100 in fig. 2 as an example, the second connection portions 143 of the bus bars 140 of the adjacent unit batteries 100 overlap each other, and after the first connection portions 142 of the bus bars 140 are connected to the pole 130, the two second connection portions 143 are welded, that is, the electrical connection of the adjacent unit batteries 100 is achieved, and the welding between the plurality of bus bars 140 is repeated to form a serial-parallel loop.

It should be noted that, referring to fig. 9, when the unit batteries 100 are arranged in the first direction and the second direction at the same time, the unit batteries 100 are arranged in a plurality of rows and a plurality of columns, and the unit batteries 100 may be arranged in the first direction first, and the adjacent unit batteries 100 may be welded sequentially in the first direction, and then the adjacent bus bars 140 may be connected through the bus bars 140 in the second direction, so that the plurality of rows and the plurality of columns of unit batteries 100 form a serial/parallel circuit. It can be appreciated that when a plurality of rows and columns of single batteries 100 are arranged in the battery pack, the single batteries 100 in the battery pack can be single batteries with one busbar 140 inside, two busbars 140 inside, two single batteries with opposite extension directions of the two busbars 140, two single batteries with two busbars 140 extending back to the adjacent side surfaces of the shell 110 inside, and according to the arrangement positions in the single batteries 100, the single batteries 100 of the corresponding types are selected for connection, so that the welding times of the busbars 140 in the box and the generated welding slag amount can be further reduced.

Referring to fig. 10, the present utility model further provides a battery pack, which includes the above-mentioned unit battery 100, and further includes a case 200, in which the unit battery 100 is mounted in the case 200, and the poles 130 of adjacent unit batteries 100 are connected by at least one bus bar 140. Because the single battery 100 is provided with the bus bars 140, after the single battery 100 is placed in the box 200, only the adjacent single batteries 100 are welded through the bus bars 140, so that the number of the welded bus bars 140 after the single battery 100 is placed in the box in the battery packaging and assembling process is reduced, the welding slag remained on the box 200 and the single battery 100 is reduced, and the safety performance of the battery pack is improved.

It should be noted that, taking the single battery 100 shown in fig. 1 as an example, after the single battery 100 is put into the box, the second connection portions 143 of the bus bars 140 of the adjacent single batteries 100 overlap, and since the first connection portions 142 of the bus bars 140 are connected with the pole 130, the two second connection portions 143 are welded to electrically connect the adjacent single batteries 100, in this case, the adjacent single batteries 100 are electrically connected through the two bus bars 140. Taking the unit cell 100 shown in fig. 2 as an example, after the unit cell 100 is put into a box, in the adjacent unit cells 100, the second connection portion 143 of the bus bar 140 of one unit cell 100 is connected to the pole 130 of the other unit cell 100, and since the first connection portion 142 of the bus bar 140 is already connected to the pole 130, the second connection portion 143 and the pole 130 are welded to realize the electrical connection of the adjacent unit cell 100, in this case, the adjacent unit cell 100 is electrically connected through one bus bar 140.

In addition, before the unit battery 100 is placed in the box 200, the battery pack 200 may be formed by welding, after the battery pack 200 is placed in the box 300, welding between adjacent battery packs 200 is performed, so that the number of welded buses 140 after the unit battery 100 is placed in the box may be further reduced.

The embodiments of the present utility model have been described in detail with reference to the accompanying drawings, but the present utility model is not limited to the above embodiments, and various changes can be made within the knowledge of one of ordinary skill in the art without departing from the spirit of the present utility model. Furthermore, embodiments of the utility model and features of the embodiments may be combined with each other without conflict.

Claims (10)

1. The battery cell, its characterized in that includes:

a battery cell;

the battery cell is accommodated in the shell;

a top cover plate, which is covered and sealed at the top of the shell;

the pole is arranged on the top cover plate;

and the bus is electrically connected with the pole.

2. The cell of claim 1, wherein the buss bar is connected to the post as an integrally formed structure.

3. The cell of claim 1, wherein the cell comprises at least two of the posts, and wherein the bus bar is connected to both of the posts;

wherein the two bus bars extend in opposite directions;

alternatively, the two bus bars respectively extend out from two adjacent side surfaces of the housing.

4. The unit cell according to claim 1, wherein the top of the top cover plate has a support portion provided protruding, the support portion being located at an edge of the top cover plate, the support portion being in contact with a bottom surface of the bus bar.

5. The battery cell according to any one of claims 1 to 4, wherein the busbar includes a first connection portion and a second connection portion connected to each other, the first connection portion and the second connection portion being respectively used to connect the poles of different battery cells.

6. The battery cell as recited in claim 5, wherein a portion of the bus bar arches toward or away from the housing to form a buffer portion, and the first and second connection portions are respectively connected to opposite sides of the buffer portion.

7. The battery cell according to any one of claims 1 to 4, wherein two of the bus bars and the poles are provided, respectively, the bus bars have a first connecting portion and a second connecting portion connected to each other, the first connecting portions of the two bus bars are connected to the two poles, respectively, and the second connecting portions are used to connect the second connecting portions of the bus bars in the other battery cell.

8. The battery cell as recited in claim 7, wherein the second connecting portion of one of the buss bars is bent downward with respect to the first connecting portion, the second connecting portion being for overlapping with the second connecting portion of the buss bar in another of the battery cells.

9. The unit cell according to claim 7, wherein the second connection portion is for overlapping with the second connection portion of the bus bar in another of the unit cells, and an upper surface of the first connection portion of the bus bar connected to each other is flush.

10. A battery pack, comprising:

a plurality of the unit cells of any one of claims 1 to 9;

the battery cell is arranged in the box body, the battery cells are at least distributed along a first direction, and the pole posts of adjacent battery cells are connected through at least one busbar.