Battery

Abstract

This application provides a battery comprising two cell stacks, each cell stack including a first clamping member and at least two cells; the first clamping member is used to constrain each cell within the cell stack; an insulating film is provided to wrap at least a portion of the two cell stacks to constrain the two cell stacks; the electrode groups of the two cell stacks are respectively welded to adapter pieces; wherein, the first clamping member can ensure that the electrode groups are neatly stacked to form electrode groups during the cell stacking process, which facilitates the welding of the electrode groups of the two cell stacks, while avoiding tearing of the welding points due to cell misalignment; the insulating film is used to constrain the relative position of the two cell stacks, which facilitates the assembly of the cell stacks into the casing, and the cell stacks are bound and restrained, but can move independently to a certain extent without pulling on the electrode groups of the other due to their own movement; that is, the reliability of the battery is effectively improved by the synergistic effect of the first clamping member and the insulating film.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more particularly to a battery. Background Technology

[0002] Currently, most high-capacity wound batteries use a structure of ≥4 cells. Multiple cells require numerous clamping components to fix them in place, in order to restrain vibrations and displacements generated during processing and under various operating conditions, and to prevent safety risks or performance failures. However, how to rationally arrange these clamping components on the cells remains to be solved. Utility Model Content

[0003] In view of the above, this application aims to provide a battery that solves some or all of the aforementioned technical problems.

[0004] For the purposes described above, this application provides a battery, comprising:

[0005] The housing and the cover plate are provided. At least one end of the housing is provided with an opening, and the cover plate is used to close the opening to form an accommodating space. The housing includes a bottom plate, which is disposed opposite to the cover plate. The cover plate is provided with a connecting piece on the side near the bottom plate. The connecting piece includes a first connecting part and a second connecting part arranged along a first direction. Two battery cell stacks are arranged in the receiving space along a first direction. Each battery cell stack includes at least one first clamping member arranged along the height direction of the battery cell stack and at least two battery cells stacked along the first direction. The tabs of each battery cell in each battery cell stack are stacked to form a tab group. The tab groups of the two battery cell stacks are respectively welded to the first connecting portion and the second connecting portion. The first clamping member is arranged around at least a portion of the at least two battery cells in the first direction to constrain each battery cell in the battery cell stack. An insulating film is provided to enclose at least a portion of the two cell stacks to constrain the two cell stacks.

[0006] Furthermore, the cover plate has an insulating element on the side facing the cell stack assembly, and the insulating film includes a thickened edge near the cover plate. The thickened edge is disposed around at least a portion of the insulating element, and the thickened edge is connected to the insulating element by thermofusion welding.

[0007] Furthermore, the insulating component includes a body portion, the body portion having protrusions at at least both ends in its length direction that protrude toward the cell stack assembly, the body portion being disposed near the cover plate, and the thickened edge being connected to the protrusions by thermofusion welding.

[0008] Furthermore, it also includes a corner constraint member, which is bonded to the side of the insulating film away from the cell stack, with a portion of the corner constraint member being disposed opposite to the side of the cell stack in the height direction, and another portion being disposed opposite to the side of the cell stack away from the cover plate.

[0009] Furthermore, it also includes a second clamping member, which is disposed around at least a portion of the two cell stacks in the height direction of the cell stacks; the tab group includes a first tab group and a second tab group with opposite polarities, and the second clamping member is located between the first tab group and the second tab group.

[0010] Furthermore, each of the cell stacks includes a first surface, a second surface, and a constraint side for connecting the first surface and the second surface, the constraint side being perpendicular to the base plate; the first clamping member is sequentially bonded to the first surface, the constraint side, and the second surface.

[0011] Furthermore, the cell stack also includes a constraint bottom surface connecting the first surface and the second surface in a first direction, the constraint bottom surface being parallel to the base plate; the second clamping member includes a non-adhesive portion and an adhesive portion located at both ends of the non-adhesive portion, the non-adhesive portion being opposite to the constraint bottom surfaces of the two cell stacks, one adhesive portion being bonded to the first surface of one cell stack, and the other adhesive portion being bonded to the second surface of the other cell stack.

[0012] Furthermore, each of the battery cells is formed by winding a first electrode, a second electrode, and an insulating film disposed between the first electrode and the second electrode with opposite polarities, and forming multiple winding layers. The first electrode and the second electrode of the multiple winding layers disposed near the second center surface are provided with tabs extending in the direction toward the cover plate. The tabs in the same battery cell stack group move closer to the second center surface to form the tab group. The outermost winding layer of the battery cell is wrapped with a separator film. The battery cell is provided with an adhesive member to constrain the tail of the separator film. The first and second fastening members do not overlap with the adhesive member. Wherein, the second center surface is the center surface of the cell stack in the first direction; the number of winding layers with the tabs accounts for at least two-thirds of the total number of winding layers.

[0013] Furthermore, in the two battery cell stacks, the tabs of each cell are all arranged facing the cover plate, the poles include a first pole and a second pole, the adapter includes a first adapter and a second adapter, and the tabs include a first tab and a second tab with opposite polarities. The first electrode extends toward the cover plate and is provided with a plurality of first electrode tabs, and the second electrode extends toward the cover plate and is provided with a plurality of second electrode tabs. The plurality of first electrode tabs in the same cell stack group are stacked to form a first electrode tab group, and the plurality of second electrode tabs in the same cell stack group are stacked to form a second electrode tab group. The first electrode tab groups of two cell stack groups are connected via the first adapter piece, and the second electrode tab groups of two cell stack groups are connected via the second adapter piece. The first adapter piece is integrally connected to the first pole post or is connected separately; the second adapter piece is integrally connected to the second pole post or is connected separately.

[0014] Furthermore, the first and second fastening members do not overlap with the first center surface; Wherein, the first center surface is the center surface of the cell stack group in its height direction; At least one of the first fastening members is disposed near the cover plate.

[0015] As described above, the battery provided in this application includes two cell stacks. Each cell within a cell stack is constrained by at least one first fastening member arranged along the height direction of the cell stack. This first fastening member constrains the relative position of each cell within the cell stack, ensuring that the tabs are neatly stacked to form a tab assembly during the stacking process. This provides a stable foundation for welding the tab assembly to the adapter plate and prevents tearing of the welding points due to cell misalignment, protecting the long-term reliability of the welding points. The two cell stacks are then wrapped and constrained by an insulating film, which effectively constrains the relative position of the two cell stacks and facilitates their assembly into the casing. Furthermore, when the cell stacks undergo relative displacement in the height direction, the insulating film's elasticity effectively buffers the force caused by this displacement, thereby reducing the pulling force of one cell stack on the tabs of the other. In other words, the two cell stacks are bound and restrained by the insulating film, but to a certain extent, they can move independently without pulling on each other's tabs due to their own movement. Through the synergistic effect of the first clamping member and the insulating film, the battery structure in this application not only achieves stable constraint within the cell stack and as a whole, but also optimizes the assembly process, effectively improving the reliability and service life of the battery. Attached Figure Description

[0016] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0017] Figure 1 This is a schematic diagram of the external structure of the battery in an embodiment of this application; Figure 2 This is a three-dimensional structural diagram of the shell according to an embodiment of this application; Figure 3 This is a schematic diagram of the cell stacking group structure in an embodiment of this application; Figure 4 for Figure 3 A schematic diagram of the side view direction; Figure 5 This is a schematic diagram of the winding configuration of two adjacent cells in a cell stacking group in an embodiment of this application; Figure 6 This is a schematic diagram of the structure of a winding layer in an embodiment of this application; Figure 7 This is a schematic diagram of the connection structure of two battery cell stacks in the unfolded state in an embodiment of this application; Figure 8 for Figure 7 A top-down view diagram; Figure 9 This is a schematic diagram of the adapter plate in the embodiments of this application; Figure 10 for Figure 9 A diagram illustrating the upward viewing direction; Figure 11 for Figure 8 A schematic diagram of the connection structure of two battery cell stacks in their assembled state; Figure 12 for Figure 11 A magnified view of a portion of the image; Figure 13 This is a schematic diagram of the structure of the battery cell stack and the cover plate after they are assembled in an embodiment of this application; Figure 14 for Figure 13 Side view direction illustration Figure 1 ; Figure 15 for Figure 13 Side view direction illustration Figure 2 ; Figure 16 This is a schematic diagram of the structure of two stacked battery cells wrapped with an insulating film in an embodiment of this application; Figure 17 for Figure 16 A schematic diagram of the side view direction; Figure 18 for Figure 16 A magnified view of a portion of the image; Figure 19 for Figure 18 A magnified view of a portion of the image; Figure 20 for Figure 17 A magnified view of a portion of the image; Figure 21 This is a schematic diagram showing the unfolded state of the insulating film in an embodiment of this application; Figure 22 for Figure 21 A schematic diagram of the side view direction; Figure 23 This is a schematic diagram of the structure of the first fastening member in an embodiment of this application; Figure 24 This is a schematic diagram of the structure of the second fastening member in the embodiments of this application. Figure 1 ; Figure 25 This is a schematic diagram of the structure of the second fastening member in the embodiments of this application. Figure 2 .

[0018] Explanation of reference numerals in the attached drawings: 100, housing; 110, base plate; 120, receiving space; 130, opening; 200, cover plate; 210, pole post; 211, first pole post; 212, second pole post; 220, adapter piece; 221, first adapter piece; 221a, first connecting part; 221b, second connecting part; 221c, protrusion; 222, second adapter piece; 230, insulating component; 231, body part; 232, protrusion; 300, cell stacking assembly; 310, cell; 310a, first surface; 310b, second surface; 310c, constrained side; 310d, constrained bottom surface; 311, first electrode; 312, second electrode; 313, separator; 313a, adhesive component; 314, winding layer; 315, tab; 315a, First electrode tab; 315b, Second electrode tab; 315c, Welding point; 316, Electrode tab assembly; 316a, First electrode tab assembly; 316b, Second electrode tab assembly; 320, First fastening element; 400, Second fastening element; 410, Non-adhesive part; 420, Adhesive part; 430, First adhesive part; 440, Second adhesive part; 500, Insulating film; 510, First main body covering area; 511, First side covering area; 520, Second main body covering area; 521, Second side covering area; 530, Bottom covering area; 531, Upper fold covering area; 540, Crease line; 550, Thickened edge; 560, Hot melt weld point; 570, Corner restraint element; X, First direction; Y, Height direction; M1, First center plane; M2, Second center plane. Detailed Implementation

[0019] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with specific embodiments and the accompanying drawings.

[0020] It should be noted that, unless otherwise defined, the technical or scientific terms used in the embodiments of this application should have the ordinary meaning understood by one of ordinary skill in the art to which this application pertains. The terms "first," "second," and similar terms used in this application do not indicate any order, quantity, or importance, but are merely used to distinguish different components. Terms such as "comprising" or "including" mean that the element or object preceding the word covers the element or object listed following the word and its equivalents, without excluding other elements or objects. Terms such as "connected" or "linked" are not limited to physical or mechanical connections, but can include electrical connections, whether direct or indirect. Terms such as "upper," "lower," "left," and "right" are only used to indicate relative positional relationships; when the absolute position of the described object changes, the relative positional relationship may also change accordingly.

[0021] As described in the background section, most high-capacity (500+ Ah) wound batteries in related technologies adopt a structure of ≥4 cells. Multiple cells are divided into two groups to form two cell stacks. Each cell in each cell stack and the two cell stacks require a large number of fastening components (such as binding tape) for fixation. Specifically, each cell in a cell stack needs to be paired and bonded by binding tape, and the two cell stacks also need to be bonded together by binding tape. For the convenience of subsequent description, in the following embodiments of this application, the binding tape used for pairing and bonding within the cell stack is referred to as pairing tape, and the tape used for bonding together is referred to as bonding tape. The pairing tape used to bond a single cell stack and the bonding tape used to bond two cell stacks can restrain the vibration and displacement generated by the cells during processing and under various operating conditions, preventing the cells from causing safety risks or performance failures.

[0022] Currently, there are no universally accepted standards in the industry regarding the binding methods and positions of mating tapes used to bond individual cell stacks and bonding tapes used to bond two cell stacks in wound batteries. The applicant has found that arbitrary adhesive placement and methods can lead to manufacturing problems, hindering stable and efficient cell assembly. For example, during battery charging and discharging, electrochemical reactions occur inside the cell, causing it to expand. This expansion primarily occurs in the central region of the cell's height. If adhesive is applied in this central region, excessive tape constraint can impede normal cell expansion. This impediment may result in uneven pressure distribution within the cell, leading to abnormal lithium plating in lithium-ion batteries and thus reducing the cell's electrochemical performance. For example, since a single cell stack consists of at least two cells and is quite heavy, when the two cell stacks are assembled into the casing, there will inevitably be some misalignment in the height direction between the two cell stacks. If the adhesive tape used is applied too tightly to the two cell stacks, it will affect the elasticity of the adhesive tape itself. Once misalignment occurs in the height direction, the weight of one cell stack can easily be transferred to the tab welding point of the other cell stack, which may cause the welding point to be pulled or even broken, thereby affecting the electrochemical performance of the cell.

[0023] Therefore, optimizing the pairing constraints of individual cells within a cell stack of a wound battery, as well as the combined cell constraints of two cell stacks, is an urgent problem to be solved.

[0024] Based on this, this application provides a battery that optimizes the pairing constraint form of each cell in the cell stack group and the combined cell constraint form of two cell stack groups to improve the electrochemical stability of the cells in the battery.

[0025] In view of this, such as Figures 1-4 , Figure 16 As shown, in some embodiments, this application provides a battery comprising: The housing 100 and the cover plate 200 are provided. At least one end of the housing 100 is provided with an opening 130. The cover plate 200 is used to close the opening 130 to form an accommodating space 120. The housing 100 includes a bottom plate 110, which is disposed opposite to the cover plate 200. The cover plate 200 is provided with a connecting piece 220 on the side near the bottom plate 110. The connecting piece 220 includes a first connecting portion 221a and a second connecting portion 221b arranged along a first direction X. Two battery cell stacks 300 are arranged in the receiving space 120 along a first direction X. Each battery cell stack 300 includes at least one first clamping member 320 arranged along the height direction Y of the battery cell stack 300 and at least two battery cells 310 stacked along the first direction X. The tabs 315 of each battery cell 310 in each battery cell stack 300 are stacked to form a tab group 316. The tab groups 316 of the two battery cell stacks 300 are respectively welded to the first connecting portion 221a and the second connecting portion 221b. The first clamping member 320 is arranged around at least a portion of the at least two battery cells 310 in the first direction X to constrain each battery cell 310 in the battery cell stack 300. An insulating film 500 is arranged to wrap at least a portion of the two battery cell stacks 300 to constrain the two battery cell stacks 300.

[0026] The first tensioning member 320 is used to constrain the relative positions of the individual cells 310 within the cell stack 300. Specifically, the first tensioning member 320 can be the aforementioned mating tape. The insulating film 500 is used to constrain the relative positions of the cell stack 300. In this embodiment, the aforementioned core-binding tape is not used; instead, the binding force of the insulating film 500 constrains the relative positions of the two cell stacks 300. It is understood that the first tensioning member 320 can be not only tape but also a ring-shaped elastic element such as a rubber band or rubber sleeve.

[0027] The first clamping member 320 is disposed around at least a portion of a cell stack 300, for example, around all sides of the cell stack 300 or only constraining a portion of the sides of the cell stack 300. Its main function is to constrain the relative position of each cell 310 within the cell stack 300, preventing displacement of the cells 310 during stacking, ensuring that the tabs 315 are neatly stacked to form a tab assembly 316, providing a stable condition for welding the tab assembly 316 to the adapter piece 220, and preventing tearing of the welding point 315c due to misalignment of the cells 310, thus protecting the long-term reliability of the welding point 315c. Furthermore, the first clamping member 320 can be configured as at least one along the height direction Y of the cell stack 300, and at least one first clamping member 320 is disposed close to the cover plate 200. For example, if there is one first clamping member 320, then the first clamping member 320 is disposed close to the cover plate 200. For example, if there are two first fastening members 320, one of them is located near the cover plate 200, and the other is located near the bottom plate 110. Specifically, by setting the first fastening member 320 near the cover plate 200, the upper part of the cell stack 300 can be effectively fixed. Near the tab 315, the initial position of the tab 315 can be effectively fixed, making it easier for the tabs 315 of each wound cell 310 to maintain a neat stacking state during the stacking process and form a neat tab group 316. This provides a prerequisite for the tab groups 316 of the subsequent two cell stack 300 to remain stable during the welding process with the first connection part 221a and the second connection part 221b of the adapter piece 220, respectively. In addition, by setting the first fastening member 320 near the cover plate 200 and near the bottom plate 110 respectively, the upper and lower parts of the cell stack 300 can be effectively fixed, which facilitates the wrapping of the two cell stack 300 by the insulating film 500.

[0028] Furthermore, it should be noted that within the cell stack 300, the tabs 315 of each cell 310 are stacked and welded to form a neat tab assembly 316, with the solder marks highly overlapping during the welding process. This structure makes the tab assembly 316 highly integral after stacking, but it also means that it is more sensitive to stress. Once the cell stack 300 is subjected to external forces, such as vibration or impact, if a slight misalignment occurs between the cells 310, the welding points 315c between the tabs 315 of each cell 310 and the overlapping solder marks will bear the brunt of the enormous tensile force. This tensile force may not only cause the welding points 315c to tear, but also disrupt the overlap of the solder marks, thereby affecting the electrical connection stability of the entire cell stack 300, and may even cause serious faults such as internal short circuits in the battery. Therefore, the setting of the first clamping member 320 is crucial. It is positioned around at least a portion of the cell stack 300, particularly near the cover plate 200, effectively securing the upper part of the cell stack 300, close to the initial position of the tabs 315. This not only makes it easier for the tabs 315 of each wound cell 310 to maintain a neat stacked state during the stacking process, but also, during subsequent use, when the battery is subjected to external forces, the first fastener 320 can effectively prevent misalignment between the cells 310 by constraining the upper part of the cell stack 300, thereby protecting the welding points 315c between the tabs 315 and the overlapping areas of the solder marks from being pulled, ensuring the long-term reliability of the welding points 315c, and providing strong protection for the safe and stable operation of the battery.

[0029] The insulating film 500, which can be a Mylar film, wraps at least a portion of the two cell stacks 300, such as wrapping all sides of the two cell stacks 300 or only some sides. Besides insulating and protecting the cells 310 from mechanical damage, its main function in this embodiment is to constrain the relative position of the two cell stacks 300, ensuring the overall structural stability of the battery. For example, during battery assembly and use, the two cell stacks 300 may experience relative displacement due to factors such as vibration, impact, or thermal expansion. This displacement can disrupt the internal structural balance of the battery, thereby affecting its performance and lifespan. The insulating film 500, by constraining the relative position of the two cell stacks 300, can effectively prevent such displacement, thus ensuring the stability of the battery's internal structure. Furthermore, the wrapping and constraining effect of the insulating film 500 on the two cell stacks 300 facilitates their assembly into the casing. Based on the above, the insulating film 500 in this embodiment can partially replace the aforementioned core adhesive, so as to constrain the relative position of the two cell stacks 300 by the wrapping force of the insulating film 500.

[0030] During actual battery assembly and use, each cell stack 300 consists of at least two cells 310, resulting in significant weight. This heavier stack 300 inevitably experiences relative displacement in the height direction (Y) due to external forces (such as vibration, impact, or thermal expansion) during casing installation or use. The insulating film 500 possesses a certain degree of elasticity. When the cell stack 300 experiences relative displacement in the height direction (Y), the insulating film 500 effectively buffers the force caused by this displacement, thereby reducing the pulling force of one cell stack 300 on the tabs 315 of another cell stack 300. Furthermore, the elasticity of the insulating film 500 allows the two cell stacks 300 to recover from vibration, impact, or thermal expansion even after relative displacement, achieving a dynamic balance in their relative positions and thus improving the battery's adaptability under dynamic conditions.

[0031] Based on the above description, the first clamping member 320 is used to constrain a single cell stack 300, and the insulating film 500 is used to constrain two cell stacks 300. Compared with the related technology where clamping members are provided in the upper, middle, and lower regions of a single cell stack 300, and where clamping members are provided in the upper, middle, and lower regions of two cell stacks 300, this not only reduces the number of clamping members but also simplifies the battery structure. Furthermore, the reduced-weight clamping member of this embodiment can meet the requirement of neatly stacked tabs 315 within a single cell stack 300, the requirement of stable welding of tabs 316 between two cell stacks 300, and the requirement of easy assembly of two cell stacks 300 into the casing. In other words, the layout of the reduced-weight clamping member + insulating film 500 in this embodiment can meet the manufacturing requirements of the entire battery, and the reduced-weight clamping member can also meet the requirements of subsequent transportation and use of the battery.

[0032] In this embodiment, the battery includes two cell stacks 300. Each cell 310 within a cell stack 300 is constrained by at least one first clamping member 320 arranged along the height direction Y of the cell stack 300. This ensures that the tabs 315 are neatly stacked to form a tab assembly 316 during the stacking process, providing a stable condition for the welding of the tab assembly 316 to the adapter piece 220. Simultaneously, it prevents the welding point 315c from tearing due to misalignment of the cells 310, protecting the long-term reliability of the welding point 315c. The two cell stacks 300 are wrapped and constrained by an insulating film 500, which effectively constrains the relative position of the two cell stacks 300 and facilitates the assembly of the cell stacks 300 into the casing. Furthermore, when the cell stacks 300 undergo relative displacement in the height direction Y, the insulating film 500, due to its own elasticity, can effectively buffer the force caused by this displacement, thereby reducing the pulling force of one cell stack 300 on the tabs 315 of the other cell stack 300. Through the synergistic effect of the first clamping member 320 and the insulating film 500, the battery structure in this embodiment not only achieves stable constraint inside and as a whole of the cell stack 300, but also optimizes the assembly process, effectively improving the reliability and service life of the battery.

[0033] In some embodiments, such as Figure 4 As shown, each of the cell stacks 300 includes a first surface 310a, a second surface 310b disposed opposite to each other along a first direction X, and a constraint side 310c for connecting the first surface 310a and the second surface 310b, the constraint side 310c being perpendicular to the base plate 110; the first fastening member 320 is sequentially bonded to the first surface 310a, the constraint side 310c and the second surface 310b.

[0034] Specifically, the cell stack group 300 includes a first surface 310a and a second surface 310b disposed opposite to each other along the first direction X. In the two cell stack groups 300, the second surface 310b of one cell stack group 300 is superimposed on the first surface 310a of the other cell stack group 300. That is, in the first direction X, the opposite sides of the two cell stack groups 300 are the first surface 310a of one cell stack group 300 and the second surface 310b of the other cell stack group 300.

[0035] For each of the two cell stack groups 300, the first fastening member 320 acts as a pairing tape, with one end bonded to the first surface 310a of the cell stack group 300 and the other end bonded to the second surface 310b of the cell stack group 300. In this way, the first fastening member 320 can bond the first surface 310a, the second surface 310b and the restraining side 310c of each cell stack group 300 together to achieve binding and restraint of each cell stack group 300, ensuring that the cells 310 in the cell stack group 300 will not be misaligned.

[0036] like Figure 3 , Figure 4 As shown, the first clamping member 320 has a U-shaped cross-section in the first direction X. Two U-shaped first clamping members 320 are provided on the upper periphery of each cell stack 300, and these two first clamping members 320 are symmetrically arranged. Compared to the technical solution of setting a full circle of first clamping members 320 around the cell stack 300, the U-shaped first clamping members 320 in this embodiment save on the amount of clamping members used, reduce the constraint area on the cell stack 300, and further reduce the increase in internal stress and lithium plating phenomenon in the cell 310 caused by excessive constraint force.

[0037] It should be noted that, as Figure 23 As shown, in this embodiment, the first fastening member 320 is a fully adhesive-backed mating tape. Since the tabs 315 of the cells 310 in the same cell stack 300 are stacked and then welded to the first connecting part 221a or the second connecting part 221b of the adapter piece 220, any relative displacement in the height direction Y will cause the welding point 315c of the tabs 315 to tear. In addition, each cell 310 in the same cell stack 300 needs to move at the same frequency. Therefore, the first fastening member 320 is fully adhesive-backed to strictly limit the position of each cell 310 in the same cell stack 300.

[0038] In some embodiments, such as Figures 16-22 The cover plate 200 is provided with an insulating member 230 on the side facing the cell stack 300. The insulating film 500 includes a thickened edge 570 near the cover plate 200. The thickened edge 570 is disposed around at least a portion of the insulating member 230. The thickened edge 570 is heat-fused to the insulating member 230.

[0039] Specifically, such as Figure 21As shown, the unfolded insulating film 500 includes a first main body covering area 510, a bottom covering area 530, and a second main body covering area 520 connected sequentially along its length. The first main body covering area 510 has first side covering areas 511 connected to both sides of its width, and the second main body covering area 520 has second side covering areas 521 connected to both sides of its width. The bottom covering area 530 has up-folded covering areas 531 on both sides of its width. The first main body covering area 510 and the first side covering areas 511... Crease lines 540 are provided between the second main body covering area 520 and the second side covering area 521, between the bottom covering area 530 and the first main body covering area 510, between the bottom covering area 530 and the second main body covering area 520, and between the bottom covering area 530 and the upper fold covering area 531. The first main body covering area 510, the first side covering area 511, the second main body covering area 520, the second side covering area 521, the bottom covering area 530, and the upper fold covering area 531 are integrally formed.

[0040] During the process of covering the two cell stacks 300, the first main covering area 510 and the second main covering area 520 are respectively opposite to the first surface 310a and the second surface 310b of the two cell stacks 300, and the first side covering area 511 and the second side covering area 521 are respectively opposite to the two opposite constraint sides 310c of the two cell stacks 300, and are covered alternately. Finally, the upper fold covering area 531 is folded up to cover, which can achieve complete coverage of all sides and bottom surfaces of the two cell stacks 300, and achieve the constraint effect on the two cell stacks 300.

[0041] In addition, such as Figure 16 , Figure 17 As shown, in this embodiment, the battery may further include a corner restraint member 570, which is bonded to the side of the insulating film 500 away from the cell stack 300. A portion of the corner restraint member 570 is positioned opposite the side of the cell stack 300 in the height direction Y, and the other portion is positioned opposite the side of the cell stack 300 away from the cover plate 200. After the two cell stacks 300 are covered, a portion of the corner restraint member 570 is bonded to the upper folded covering area 531 (the upper folded covering area 531, the first side covering area 511, and the second side covering area 521 are bonded together), and the other portion is bonded to the bottom covering area 530. This provides more effective restraint to the lower part of the insulating film 500, thereby effectively restraining the lower part of the two cell stacks 300 and facilitating the insertion of the two cell stacks 300 into the casing.

[0042] In addition, in this embodiment, the insulating film 500 also includes a thickened edge 570 on the side near the cover plate 200. That is, the first main body covering area 510, the second main body covering area 520, the first side covering area 511, and the second side covering area 521 are all provided with a thickened edge 570 on the side away from the bottom covering area 530. The thickened edge 570 is an edge that protrudes towards the cell stack 300 relative to the first main body covering area 510, the second main body covering area 520, the first side covering area 511, and the second side covering area 521. Furthermore, the cover plate 200 is provided with an insulating member 230 on the side facing the cell stack 300. The insulating member 230 can be made of plastic. Both the thickened edge 570 and the insulating member 230 are made of insulating material. The two are hot-melt welded together, and the welding effect is more solid. That is, it can effectively constrain the two cell stacks 300, especially the upper part of the two cell stacks 300. In addition, welding the thickened edge 570 to the insulating component 230 can increase the coverage area of ​​the insulating film 500 on the two cell stacks 300, prevent the tabs 315 from extending too far to contact the casing 100, and improve the insulation and safety performance of the battery.

[0043] In this embodiment, the lower part of the insulating film 500 is constrained by the corner constraint member 570, and the upper part of the insulating film 500 is constrained by the hot-melt welding of the thickened edge 570 of the insulating film 500 to the insulating member 230. This further strengthens the constraint effect of the insulating film 500 on the cell stack 300, improves the overall performance and reliability of the battery, and also provides a strong guarantee for the safe operation of the battery.

[0044] In some embodiments, reference Figure 18 , Figure 19 The insulating component 230 includes a body portion 231, and the body portion 231 has protrusions 232 at at least both ends in its length direction that protrude toward the battery cell stack 300. The body portion 231 is located near the cover plate 200, and the thickened edge 570 is connected to the protrusions 232 by thermofusion welding.

[0045] like Figure 18 The insulating component 230 has protrusions 232 at both ends and in the middle of its body 231, which face the cell stack 300. Since the body 231 of the insulating component 230 is generally thin and unsuitable for hot-melt welding with the thickened edge 570, hot-melt welding is chosen between the thickened edge 570 and the protrusions 232. This allows for easier positioning and operation of the welding equipment, ensuring the accuracy of the weld point 315c. Furthermore, the hot-melt weld between the protrusions 232 and the thickened edge 570, with its intermittent design, effectively disperses stress in the area of ​​the hot-melt weld point 560, reducing the risk of breakage due to stress concentration.

[0046] In some embodiments, reference Figure 13 The battery also includes a second clamping member 400, which is disposed around at least a portion of the two cell stacks 300 in the height direction Y of the cell stack 300; the tab group 316 includes a first tab group 316a and a second tab group 316b with opposite polarities, and the second clamping member 400 is located between the first tab group 316a and the second tab group 316b.

[0047] The second clamping member 400 is provided to further enhance the constraint effect on the two cell stack groups 300, based on the first clamping member 320 and the insulating film 500. The second clamping member 400 is the aforementioned core-binding tape.

[0048] The second clamping member 400 is located between the first tab group 316a and the second tab group 316b. Specifically, the second clamping member 400 is disposed around at least a portion of the two cell stack groups 300, for example, it is disposed around the entire circle of the two cell stack groups 300 or it only constrains a portion of the sides of the two cell stack groups 300. Its main function is to constrain the relative position of the two cell stack groups 300 and ensure the overall structural stability of the battery. In addition, the second clamping member 400 is disposed between the two tab groups 316b, which can reduce the shaking amplitude of the cell stack group 300 when subjected to external impact, and reduce the risk of short circuit caused by loosening of the internal structure of the cell stack group 300.

[0049] In some embodiments, such as Figure 13 , Figure 14 , Figure 24 As shown, the cell stack 300 further includes a constraint bottom surface 310d connecting the first surface 310a and the second surface 310b in the first direction X, and the constraint bottom surface 310d is parallel to the base plate 110; the second clamping member 400 includes a non-adhesive portion 410 and adhesive portions 420 located at both ends of the non-adhesive portion 410, the non-adhesive portion 410 is opposite to the constraint bottom surfaces 310d of the two cell stacks 300, one adhesive portion 420 is bonded to the first surface 310a of one cell stack 300, and the other adhesive portion 420 is bonded to the second surface 310b of the other cell stack 300.

[0050] The second clamping member 400 is bonded to the first surface 310a and the second surface 310b of the two cell stacks 300 via two adhesive portions 420, respectively. The non-adhesive portion 410 located between the two adhesive portions 420 is only opposite to the constraint bottom surface 310d of the two cell stacks 300; this portion is not adhesive-backed and is not bonded to the constraint bottom surface 310d of the cell stacks 300. This design ensures that the relative position of the two cell stacks 300 in the first direction X is effectively constrained, preventing relative displacement in the first direction X during assembly and use. The non-adhesive portion 410 enhances the elasticity of the second clamping member 400, thereby improving the battery's adaptability under dynamic conditions.

[0051] It should be noted that, in order to ensure the stability of battery use, theoretically, it is desirable that there is no relative displacement between the two cell stacks 300, either in the first direction (X) or in the height direction (Y). However, in actual assembly and use, since each cell stack 300 consists of at least two cells 310, its weight is relatively large. Such a heavy cell stack 300 will inevitably experience relative displacement in the height direction (Y) due to external forces (such as vibration, impact, or thermal expansion) during casing or use. If this displacement is not controlled, it may lead to damage to the internal structure of the battery, thereby affecting the battery's performance and safety.

[0052] In traditional designs, the second clamping member 400 typically uses a fully adhesive backing, meaning the entire back of the clamping member is sticky. While this design provides strong fixing force, it also has some significant limitations. First, the fully adhesive backing design affects the elasticity of the second clamping member 400. When the cell stack 300 experiences relative displacement, the clamping member, lacking elasticity, cannot effectively buffer the force from this displacement. Second, once misalignment occurs, the fully adhesive clamping member is difficult to return to its original position, which may lead to breakage. More seriously, the weight of the cell stack 300 may be transferred to the electrode tab 315 welding point 315c of the other cell stack 300, causing tension on the electrode tab 315. This tension not only affects the stability of the welding point 315c but may also damage the electrode tab 315, potentially leading to safety issues such as internal battery short circuits.

[0053] To address the problems inherent in traditional designs, this embodiment introduces a non-adhesive portion 410. Specifically, the second clamping member 400 includes a non-adhesive portion 410 and adhesive portions 420 located at both ends of the non-adhesive portion 410. The non-adhesive portion 410 faces the constraint bottom surface 310d of the two cell stacks 300 but is not bonded to the constraint bottom surface 310d, while the adhesive portions 420 are bonded to the first surface 310a and the second surface 310b of the two cell stacks 300, respectively. The key advantage of this design is that the presence of the non-adhesive portion 410 provides the second clamping member 400 with greater elasticity in this region. When the cell stack 300 undergoes relative displacement in the height direction Y, the non-adhesive portion 410 can effectively buffer the force caused by this displacement, thereby reducing the pulling of one cell stack 300 on the tab 315 of another cell stack 300. In addition, the presence of the non-adhesive portion 410 allows the two cell stacks 300 to recover from vibration, impact or thermal expansion when relative displacement occurs, so that the relative positions of the two cell stacks 300 can reach a dynamic balance, thereby improving the battery's adaptability under dynamic conditions.

[0054] In this embodiment, by introducing a non-adhesive portion 410 into the second clamping member 400, and having the non-adhesive portion 410 opposite to the constraint bottom surface 310d of the two cell stacks 300, the overall elasticity of the second clamping member 400 is enhanced. When the two cell stacks 300 experience relative displacement in the height direction Y, the non-adhesive portion 410 will share most of the weight of the cell stacks 300, preventing one cell stack 300 from pulling on the tab 315 of the other cell stack 300, thereby improving the battery's adaptability under dynamic conditions.

[0055] In some embodiments, such as Figure 13 , Figure 14 , Figure 25 As shown, the cell stack 300 further includes a constraint bottom surface 310d that connects the first surface 310a and the second surface 310b in the first direction X, and the constraint bottom surface 310d is parallel to the base plate 110; the second fastening member 400 includes a first adhesive portion 430 and second adhesive portions 440 located at both ends of the first adhesive portion 430, the first adhesive portion 430 is bonded to the constraint bottom surfaces 310d of the two cell stacks 300, one second adhesive portion 440 is bonded to the first surface 310a of one cell stack 300, and the other second adhesive portion 440 is bonded to the second surface 310b of the other cell stack 300; The second clamping member 400 is bonded to the first surface 310a and the second surface 310b of the two cell stacks 300 respectively via two second adhesive portions 440. A first adhesive portion 430 located between the two second adhesive portions 440 is opposite to and bonded to the constraint bottom surface 310d of the two cell stacks 300. This design ensures that the relative positions between the two cell stacks 300 are effectively constrained. However, the adhesive strength of the first adhesive portion 430 is less than that of the second adhesive portion 440. Compared to cases where both the backing adhesives of the second clamping member 400 have a second strength, the provision of the first adhesive portion 430 enhances the elasticity of the second clamping member 400, thereby improving the battery's adaptability under dynamic conditions.

[0056] Specifically, the presence of the first adhesive portion 430 gives the second clamping member 400 greater elasticity in this area. When the cell stack 300 undergoes relative displacement in the height direction Y, the first adhesive portion 430 can effectively buffer the force caused by this displacement, thereby reducing the pulling on the welding point 315c of the tab 315. In addition, the first adhesive portion 430 does not firmly bond the constraint bottom surface 310d of the two cell stack 300s, so that the two cell stack 300s will recover with changes in vibration, impact or thermal expansion when relative displacement occurs, so that the relative position of the two cell stack 300s can reach a dynamic balance, thereby improving the battery's adaptability under dynamic conditions.

[0057] In this embodiment, by introducing a first adhesive portion 430 and a second adhesive portion 440 with different adhesive strengths into the second fastening member 400, the adhesive strength of the first adhesive portion 430 is less than that of the second adhesive portion 440, making the second fastening member 400 more elastic at the first adhesive portion 430. The first adhesive portion 430 is opposite to and bonded to the constraint bottom surface 310d of the two cell stack groups 300, but its bonding effect is not very strong. When the two cell stack groups 300 have a relative displacement in the height direction Y, the first adhesive portion 430 will share most of the weight of the cell stack group 300, avoiding the pulling of the tab 315 of the other cell stack group 300 by one cell stack group 300, thereby improving the adaptability of the battery under dynamic conditions.

[0058] In some embodiments, such as Figure 5 , Figure 6As shown, each of the battery cells 310 is formed by winding a first electrode 311, a second electrode 312 with opposite polarities and a separator 313 disposed between the first electrode 311 and the second electrode 312, forming a plurality of winding layers 314. The first electrode 311 and the second electrode 312 of the plurality of winding layers 314 disposed near the second center surface M2 are provided with tabs 315 extending in the direction toward the cover plate 200. The tabs 315 in the same battery cell stack group 300 move closer to the second center surface M2 to form the tab group 316.

[0059] like Figure 3 , Figure 7 , Figure 13 As shown, the outermost winding layer 314 of the battery cell 310 is wrapped by the separator 313. The battery cell 310 is provided with an adhesive member 313a for constraining the tail of the separator 313. The first fastening member 320 and the second fastening member 400 do not overlap with the adhesive member 313a.

[0060] Wherein, the second center surface M2 is the center surface of the cell stack 300 in the first direction X; the number of winding layers 314 with tabs 315 accounts for at least two-thirds of the total number of winding layers 314.

[0061] The separator 313 is longer than both the first electrode 311 and the second electrode 312, so that after the first electrode 311 and the second electrode 312 are wound, the excess separator 313 can be used to wrap the outermost winding layer 314. Therefore, the cell 310 also includes an adhesive member 313a to restrain the tail of the separator 313. Figure 3 , Figure 13 As shown, this maintains the constraint of the separator 313 on each winding layer 314 and prevents the tail of the separator 313 from lifting. The first clamping member 320 and the second clamping member 400 do not overlap with the adhesive member 313a. That is, whether in the height direction Y of the cell stack 300 or in the first direction X, the first clamping member 320 or the second clamping member 400 does not form a closed-loop bond with the adhesive member 313a. This allows the cell 310 to expand freely during charging and discharging, further reducing the resistance to the expansion of the cell 310 and optimizing the electrochemical performance of the battery.

[0062] Furthermore, such as Figure 15As shown, the first clamping member 320 and the second clamping member 400 do not overlap with the first center surface M1; wherein, the first center surface M1 is the center surface of the cell stack 300 in its height direction Y. That is, the first clamping member 320 and the second clamping member 400 also avoid the central region where the cell 310 expands the most, allowing the cell 310 to expand freely during charging and discharging, further reducing the resistance to the expansion of the cell 310 and optimizing the electrochemical performance of the battery.

[0063] Optionally, the distance L1 between the first clamping member 320 and the first center surface M1, and the distance L2 between the second clamping member 400 and the first center surface M1, are both greater than or equal to one-fifth of the height of the cell stack 300. This design ensures that the clamping members do not get too close to the central region of the cell stack 300, thereby avoiding excessive constraint on the expansion of the cell 310. Furthermore, this design results in a relatively large distance between the first clamping member 320 and the second clamping member 400. This layout ensures the stability of the battery structure while also providing sufficient space for the normal expansion of the cell 310, further optimizing the overall performance and reliability of the battery.

[0064] In this battery, the first electrode 311 can be a positive electrode, serving as the positive electrode material and responsible for providing lithium ions in the electrochemical reaction. The second electrode 312 can be a negative electrode, serving as the negative electrode material and responsible for the insertion and extraction of lithium ions in the electrochemical reaction. A separator 313 is disposed between the first electrode 311 and the second electrode 312 to prevent direct contact between the positive and negative electrodes, avoiding short circuits, while allowing lithium ions to pass through. The battery cell 310 forms multiple wound layers 314 by winding the first electrode 311, the second electrode 312, and the separator 313 together. This winding structure gives the battery cell 310 high energy density and good electrochemical performance.

[0065] In this embodiment, the winding structure of the battery cell 310 is designed such that the first electrode 311 and the second electrode 312 of multiple winding layers 314 near the second center surface M2 extend toward the cover plate 200 to form a tab group 316. Specifically, each battery cell 310 is formed by winding a first electrode 311, a second electrode 312, and an insulating film 313 disposed between them, forming multiple winding layers 314. To optimize the current transmission path, the first electrode 311 and the second electrode 312 of the multiple winding layers 314 near the second center surface M2 extend toward the cover plate 200 to form tabs 315. These tabs 315 move closer to the second center surface M2 in the battery cell stack 300, ultimately forming a neat tab group 316. The tabs 316 of the two cell stacks 300 are welded to the first connecting portion 221a and the second connecting portion 221b of the adapter piece 220, respectively, and the adapter piece 220 is connected to the terminal post 210 on the cover plate 200. Thus, a current transmission path consisting of the electrode, the tab 315, the adapter piece 220 and the terminal post 210 is formed.

[0066] In this embodiment, the number of winding layers 314 with tabs 315 accounts for at least two-thirds of the total number of winding layers 314. For example, if the number of winding layers 314 of two cells 310 in a cell stack 300 is 30 layers each, then at least two-thirds of the winding layers 314 will have tabs 315, that is, each cell 310 will have 20 winding layers 314 with tabs 315. These 20 winding layers 314 are all located close to the second center surface M2, and the tabs 315 of each of the 20 winding layers 314 of the two cells 310 will move towards the second center surface M2 to form a tab group 316. The reason for this design is that the closer the tabs 315 are to the second center surface M2, the shorter the current transmission path and the smaller the internal resistance, thereby improving electrical efficiency. In addition, the fact that the number of winding layers 314 with tabs 315 accounts for at least two-thirds of the total number of winding layers 314 can increase the number of current collection points. More current collection points mean that current can be transmitted to the tab 315 through more paths, thereby improving the efficiency of current collection.

[0067] Furthermore, the tabs 315 of both cells 310 are brought closer together towards the second center surface M2, forming a tab assembly 316 which is then welded to the adapter piece 220. It is worth noting that the cells 310 generate heat during operation, and the tabs 315 are not only key components for current transmission but also important pathways for heat dissipation. This arrangement results in more uniform heat dissipation for the two cells 310. Because the tab assembly 316 is close to the second center surface M2 and neatly arranged, heat can be dissipated more evenly to the outside of the cell stack 300 through the tabs 315, preventing localized overheating and improving the overall thermal stability of the battery. This optimized tab 315 layout not only improves current transmission efficiency but also enhances the heat dissipation performance of the cells 310, enabling the battery to maintain good operating conditions even under high loads and extending its lifespan.

[0068] In some embodiments, reference Figure 4 , Figures 7-14 In the two battery cell stacks 300, the tabs 315 of each cell 310 are all facing the cover plate 200. The pole 210 includes a first pole 211 and a second pole 212. The adapter 220 includes a first adapter 221 and a second adapter 222. The tabs 315 include a first tab 315a and a second tab 315b with opposite polarities. The first electrode 311 extends toward the cover plate 200 and is provided with a plurality of first electrode tabs 315a. The second electrode 312 extends toward the cover plate 200 and is provided with a plurality of second electrode tabs 315b. The plurality of first electrode tabs 315a in the same cell stack 300 are stacked to form a first electrode tab group 316a. The plurality of second electrode tabs 315b in the same cell stack 300 are stacked to form a second electrode tab group 316b. The first electrode tab groups 316a of two cell stacks 300 are connected via the first adapter piece 221. The second electrode tab groups 316b of two cell stacks 300 are connected via the second adapter piece 222. The first adapter piece 221 is integrally connected to the first pole piece 211 or is separately connected; the second adapter piece 222 is integrally connected to the second pole piece 212 or is separately connected.

[0069] The first tab group 316a is formed by stacking multiple first tabs 315a (positive tabs) within the same cell stack group 300. The second tab group 316b is formed by stacking multiple second tabs 315b (negative tabs) within the same cell stack group 300. A first adapter piece 221 connects the first tab groups 316a of the two cell stack groups 300 to ensure efficient transmission of positive current. A second adapter piece 222 connects the second tab groups 316b of the two cell stack groups 300 to ensure efficient transmission of negative current. A first terminal post 211 is connected to the first adapter piece 221 to transmit positive current to the outside of the battery. A second terminal post 212 is connected to the second adapter piece 222 to transmit negative current to the outside of the battery. The first adapter piece 221 and the first terminal post 211, and the second adapter piece 222 and the second terminal post 212, can be integrally connected or separately connected. Integrated connections reduce resistance at connection points and improve current transmission efficiency; separate connections facilitate assembly and maintenance.

[0070] Further optionally, the adapter piece 220 may also include a protrusion 221c located between the first connecting portion 221a and the second connecting portion 221b, the protrusion 221c extending toward the cover plate 200.

[0071] Specifically, the first connecting portion 221a of the first adapter piece 221 is used to weld to the first tab group 316a of a cell stack 300, and the second connecting portion 221b is used to weld to the first tab group 316a of another cell stack 300. The first connecting portion 221a of the second adapter piece 222 is used to weld to the second tab group 316b of a cell stack 300, and the second connecting portion 221b is used to weld to the second tab group 316b of another cell stack 300.

[0072] The protrusion 221c is located between the first connecting portion 221a and the second connecting portion 221b, extending towards the cover plate 200. During the welding process between the adapter piece 220 and the pole post 210, the protrusion 221c ensures more accurate alignment between the adapter piece 220 and the pole post 210. As the center point for welding, the protrusion 221c provides precise positioning for the welding of the adapter piece 220 and the pole post 210, thereby reducing welding deviation and improving welding quality.

[0073] In this embodiment, the tabs 315 of the two cell stacks 300 are both positioned facing the cover plate 200, forming a first tab group 316a and a second tab group 316b. A first adapter piece 221 connects the first tab groups 316a of the two cell stacks 300, and a second adapter piece 222 connects the second tab groups 316b of the two cell stacks 300, and is connected to the first terminal post 211 and the second terminal post 212 on the cover plate 200 respectively, achieving efficient current transmission. The adapter piece 220 is designed to include a protrusion 221c, located between the first connecting portion 221a and the second connecting portion 221b, extending towards the cover plate 200. The protrusion 221c serves as a center point during the welding process between the adapter piece 220 and the terminal post 210, ensuring accurate alignment between the adapter piece 220 and the terminal post 210, reducing welding deviation, and improving welding quality. This design not only optimizes the current transmission path and reduces internal resistance, but also enhances the stability and reliability of welding, thereby improving the overall performance and safety of the battery.

[0074] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of this application (including the claims) is limited to these examples; within the framework of this application, the technical features of the above embodiments or different embodiments can also be combined, the steps can be implemented in any order, and there are many other variations of the different aspects of this application as described above, which are not provided in the details for the sake of brevity.

[0075] The embodiments of this application are intended to cover all such substitutions, modifications, and variations that fall within the broad scope of the appended claims. Therefore, any omissions, modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application should be included within the protection scope of this application.

Claims

1. A battery, characterized by, include: The housing and the cover plate are provided. At least one end of the housing is provided with an opening, and the cover plate is used to close the opening to form an accommodating space. The housing includes a bottom plate, which is disposed opposite to the cover plate. The cover plate is provided with a connecting piece on the side near the bottom plate. The connecting piece includes a first connecting part and a second connecting part arranged along a first direction. Two battery cell stacks are arranged in the receiving space along a first direction. Each battery cell stack includes at least one first clamping member arranged along the height direction of the battery cell stack and at least two battery cells stacked along the first direction. The tabs of each battery cell in each battery cell stack are stacked to form a tab group. The tab groups of the two battery cell stacks are respectively welded to the first connecting part and the second connecting part. The first clamping member is arranged around at least a portion of the at least two battery cells in the first direction to constrain each battery cell in the battery cell stack. as well as An insulating film is provided to enclose at least a portion of the two cell stacks to constrain the two cell stacks.

2. The battery of claim 1, wherein, The cover plate has an insulating element on the side facing the cell stack assembly. The insulating film includes a thickened edge near the cover plate. The thickened edge is disposed around at least a portion of the insulating element, and the thickened edge is connected to the insulating element by thermofusion welding.

3. The battery of claim 2, wherein, The insulating component includes a body portion, which has protrusions at at least both ends in its length direction that are directed toward the battery cell stack assembly. The body portion is located close to the cover plate, and the thickened edge is connected to the protrusions by thermofusion welding.

4. The battery of claim 2, wherein, It also includes a corner restraint, which is bonded to the side of the insulating film away from the cell stack, with a portion of the corner restraint facing the side of the cell stack in the height direction and another portion facing the side of the cell stack away from the cover plate.

5. The battery of claim 1, wherein, It also includes a second fastening member, which is disposed around at least a portion of the two cell stacks in the height direction of the cell stacks; the tab group includes a first tab group and a second tab group with opposite polarities, and the second fastening member is located between the first tab group and the second tab group.

6. The battery of claim 5, wherein, Each of the cell stacks includes a first surface, a second surface, and a constraint side for connecting the first surface and the second surface, the constraint side being perpendicular to the base plate; the first clamping member is sequentially bonded to the first surface, the constraint side, and the second surface.

7. The battery of claim 6, wherein, The cell stack also includes a constraint bottom surface that connects the first surface and the second surface in a first direction, the constraint bottom surface being parallel to the base plate; the second clamping member includes a non-adhesive portion and an adhesive portion located at both ends of the non-adhesive portion, the non-adhesive portion being opposite to the constraint bottom surfaces of the two cell stacks, one adhesive portion being bonded to the first surface of one cell stack, and the other adhesive portion being bonded to the second surface of the other cell stack.

8. The battery of claim 5, wherein, Each of the aforementioned cells is formed by winding a first electrode, a second electrode, and a separator disposed between the first electrode and the second electrode with opposite polarities, and forming multiple winding layers. The first electrode and the second electrode of the multiple winding layers disposed near the second center surface are provided with tabs extending in the direction toward the cover plate. The tabs in the same cell stack group move closer to the second center surface to form the tab group. The outermost winding layer of the battery cell is wrapped with a separator film. The battery cell is provided with an adhesive member to constrain the tail of the separator film. The first and second fastening members do not overlap with the adhesive member. Wherein, the second center surface is the center surface of the cell stack in the first direction; the number of winding layers with the tabs accounts for at least two-thirds of the total number of winding layers.

9. The battery of claim 8, wherein, It also includes pole posts, in which the tabs of each cell in the two cell stacks are all arranged facing the cover plate, the pole posts include a first pole post and a second pole post, the adapter includes a first adapter and a second adapter, and the tabs include a first tab and a second tab with opposite polarities; The first electrode extends toward the cover plate and is provided with a plurality of first electrode tabs, and the second electrode extends toward the cover plate and is provided with a plurality of second electrode tabs. The plurality of first electrode tabs in the same cell stack group are stacked to form a first electrode tab group, and the plurality of second electrode tabs in the same cell stack group are stacked to form a second electrode tab group. The first electrode tab groups of two cell stack groups are connected via the first adapter piece, and the second electrode tab groups of two cell stack groups are connected via the second adapter piece. The first adapter piece is integrally connected to the first pole post or is connected separately; the second adapter piece is integrally connected to the second pole post or is connected separately.

10. The battery of claim 5, wherein, The first and second fastening members do not overlap with the first center surface; Wherein, the first center surface is the center surface of the cell stack group in its height direction; At least one of the first fastening members is disposed near the cover plate.

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