Battery pack

Abstract

This application discloses a battery pack comprising multiple square battery cells arranged in an array and an adhesive member. Each square battery cell includes two opposing first surfaces and two opposing second surfaces, which are adjacent and interconnected. The area of ​​the first surface is larger than the area of ​​the second surface. The adhesive member is disposed between the second surfaces of two adjacent square battery cells; the overlap area between the adhesive member and the first surface is zero. In the battery pack provided by this application, adjacent square battery cells can be fixedly connected by the adhesive member, which restricts the adhesive member from entering the first surface, preventing lithium plating caused by the adhesive member pressing against the first surface. Furthermore, by placing the adhesive member on the second surface, stress is difficult to effectively penetrate the internal space of the square battery cell to act on the electrode, thus avoiding the generation of local high-voltage points that would obstruct lithium-ion transport. This prevents lithium plating problems caused by uneven pressure and ensures the cycle life of the square battery cells.

Description

Technical Field

[0001] This application relates to the field of energy storage equipment technology, and more specifically, to a battery pack. Background Technology

[0002] The battery pack in this technology includes prismatic cells arranged in an array, with adhesive joints between adjacent rows and columns of cells. Specifically, the adhesive joints act on the rounded corners where the large and small faces of the prismatic cells meet. If the battery pack vibrates during use, the adhesive joints can compress the rounded corners. Since the rounded corners and small faces have small areas and are not easily deformed, this compression can cause deformation of the large faces. This could lead to mechanical fatigue due to frequent deformation, resulting in leakage and affecting the cycle life of the prismatic cells. Furthermore, the adhesive joints may overflow onto the large faces during use and solidify there. When the battery pack vibrates during use, the solidified adhesive joints can compress the large faces, causing lithium plating, which also affects the cycle life of the prismatic cells. Utility Model Content

[0003] This application provides a battery pack to solve at least one of the technical problems mentioned above.

[0004] The battery pack according to the embodiments of this application includes: Multiple square battery cells arranged in an array, each square battery cell comprising two opposing first surfaces and two opposing second surfaces, the first surfaces and the second surfaces being adjacent and connected to each other, the area of ​​the first surface being larger than the area of ​​the second surface; An adhesive is disposed between the second surfaces of two adjacent square battery cells; the overlap area between the adhesive and the first surface is 0.

[0005] The battery pack provided in this application allows adjacent square cells to be fixedly connected by adhesive members, which restrict the adhesive members from entering the first surface, preventing lithium plating caused by the adhesive members pressing against the first surface. Furthermore, placing the adhesive members on the second surface, due to its smaller area, results in higher rigidity, reducing deformation and preventing mechanical fatigue from frequent deformation. The high rigidity of the second surface also ensures that most of the stress from the adhesive members is confined to the small surface itself and the surrounding casing material. Stress is difficult to effectively penetrate the internal space of the square cell and act on the electrodes, thus preventing the formation of localized high-voltage points that would obstruct lithium-ion transport. This prevents lithium plating caused by uneven pressure and ensures the cycle life of the square cells.

[0006] In some embodiments, the adhesive is a structural adhesive or a foam adhesive.

[0007] Thus, by using structural adhesives or foam adhesives as bonding components, it is beneficial to select bonding components with appropriate strength, elasticity, or weight characteristics according to different application requirements, so as to achieve a stable and reliable connection between square battery cells.

[0008] In some embodiments, the elastic modulus of the adhesive is 10~1000MPa.

[0009] Thus, the bonded parts have a certain degree of flexibility, which can effectively absorb and dissipate impact energy and vibration.

[0010] In some embodiments, the battery pack further includes a stop disposed between the second surfaces of two adjacent square cells, the stop being configured to prevent the adhesive from entering the first surface.

[0011] Thus, by using a stopper to prevent the adhesive from entering the first surface, the adhesive is prevented from squeezing the first surface, which could cause the first surface of the square battery cell to rupture and leak liquid due to mechanical fatigue caused by frequent deformation.

[0012] In some embodiments, the second surface includes two first sides connected to the first surface, and the stop includes two first stop strips, each of which is disposed close to and substantially parallel to the corresponding first side.

[0013] Thus, by placing the foam strips on the two first sides adjacent to the first surface, it is beneficial to precisely block the adhesive from flowing to the first surface area where stress concentration is most likely to occur.

[0014] In some embodiments, the length of the first stop bar is 60% to 100% of the length of the first side.

[0015] Thus, by limiting the length of the foam strip to 60% to 100% of the length of the second surface, it is beneficial to provide sufficient adhesive application area for the bonded parts to ensure bonding strength while ensuring effective adhesive blocking.

[0016] In some embodiments, the second surface includes a second side connected to both ends of the two first sides, and the stop includes a second stop strip disposed near one of the second sides and substantially parallel to the corresponding second side.

[0017] Thus, by placing the foam strips on the two first sides adjacent to the rounded corner, it is beneficial to precisely block the adhesive from flowing to the rounded corner area where stress concentration is most likely to occur.

[0018] In some embodiments, the second surface includes a second side connected to both ends of the two first sides, and the stop includes two second stop strips, each of the second stop strips being disposed close to and substantially parallel to the corresponding second side.

[0019] Thus, by setting stop strips on both second sides, it is beneficial to achieve more comprehensive enclosure of the adhesive, preventing it from overflowing from either side to the rounded corner or the first surface, and ensuring the reliability of the blocking effect.

[0020] In some embodiments, the length of the second stop bar is 60% to 100% of the length of the second side.

[0021] Thus, by limiting the length of the foam strip set on the second side to 60% to 100% of the width of the second surface, it is beneficial to provide sufficient adhesive application area for the bonded parts to ensure bonding strength while ensuring effective adhesive blocking.

[0022] In some embodiments, the first stop bar and the second stop bar form a U-shape, an inverted U-shape, or a square shape on the second surface.

[0023] Thus, by arranging the stop strips in a U-shape, inverted U-shape, or square shape, it is beneficial to form a closed or semi-closed bonding area on the second surface, thereby more effectively confining the bonded part within a predetermined range and preventing it from overflowing.

[0024] In some embodiments, the elastic modulus of the first stop bar and / or the second stop bar is 1-50 MPa.

[0025] Thus, using a first stop bar and / or a second stop bar with a low elastic modulus is beneficial for providing excellent shock absorption and damping effects for two adjacent square cells.

[0026] In some embodiments, the first stop strip or the second stop strip is a foam strip.

[0027] Thus, by using foam strips as a stop, it is beneficial to take advantage of their soft and compressible properties to adapt to the slight unevenness on the surface of the square battery cell, ensuring the stopping effect while avoiding additional hard pressure on the square battery cell.

[0028] In some embodiments, the foam strip includes two adhesive backing surfaces, which are respectively bonded to the second surface of two adjacent square battery cells.

[0029] Thus, by placing only one layer of foam strip between two adjacent square cells, it is beneficial to simplify the assembly process, reduce production costs, and ensure sufficient adhesive protection.

[0030] In some embodiments, the foam strip is compressed between two adjacent square cells, and the thickness of the compressed foam strip is 0.5 to 2 mm.

[0031] Thus, by limiting the thickness of the compressed foam strip to 0.5–2 mm, it is beneficial to limit the thickness of the bonded part to within 0.5–2 mm, thereby ensuring that the bonded part has the best mechanical properties.

[0032] In some embodiments, the compression rate of the foam strip is 45% to 55%.

[0033] In this way, the foam strips can provide sufficient support while retaining ample cushioning space.

[0034] In some embodiments, an adhesive area is formed on the second surface, the adhesive area being located between the two first stop strips, the adhesive member being disposed within the adhesive area, and the area of ​​the adhesive area being greater than 60% of the second surface.

[0035] In this way, the bonding area is 60% larger than the second surface, which not only ensures that the bonded parts have sufficient bonding area, but also strictly limits the glue application range to prevent glue overflow.

[0036] In some embodiments, the battery pack includes at least two battery packs, each battery pack including a plurality of square cells stacked and aligned along a direction perpendicular to the first surface, with adjacent battery packs arranged along a direction perpendicular to the second surface; The stopper is a stop film, which is disposed between two adjacent battery packs. The stop film has multiple hollowed-out bonding areas, and the orthographic projection of each bonding area on the square battery cell is within the range of the second surface. The adhesive is disposed within the bonding area.

[0037] In this way, by using a stop film that covers the entire battery pack and opening multiple aligned hollow bonding areas, it is beneficial to achieve uniform and precise adhesive application on the second surface of all square cells, which greatly improves the efficiency and consistency of mass production, while avoiding the tedious process of pasting stop strips one by one.

[0038] In some embodiments, the barrier film is made of PEC or PC.

[0039] Thus, by using PET or PC film as a barrier, the adhesive components can be effectively isolated by utilizing their smoothness, high strength, and chemical resistance, providing a thin and highly rigid adhesive barrier solution.

[0040] In some embodiments, the thickness of the barrier film is 0.015 to 0.5 mm.

[0041] Thus, by limiting the thickness of the PET or PC film to 0.015–0.5 mm, it is beneficial to minimize additional weight and space occupation while ensuring sufficient mechanical strength to block the adhesive.

[0042] In some embodiments, the bonding area is a rectangular region aligned with the second surface, the length of the bonding area is 60% to 95% of the length of the second surface, and the width of the bonding area is 60% to 90% of the width of the second surface.

[0043] In this way, by limiting the length and width of the opening to specific proportions of the length and width of the second surface, it is beneficial to ensure that the bonding area is large enough to provide a solid bond, while leaving a sufficiently wide retaining edge around it to prevent glue overflow.

[0044] In some embodiments, the battery pack further includes a structural plate disposed between two adjacent battery packs, and the adhesive is disposed between the structural plate and the battery packs and configured to adhesive the structural plate to the second surface.

[0045] Thus, by placing the adhesive between the structural plate and the second surface, a reliable connection between the square cell and the structural plate is achieved, which helps to enhance the overall structural strength of the battery pack.

[0046] In some embodiments, the structural plate is an insulating plate.

[0047] Therefore, by using insulating boards to make structural panels, it is beneficial to utilize their excellent insulation properties to meet the safety requirements of battery packs.

[0048] In some embodiments, the length of the structural plate is less than the length of the corresponding battery pack.

[0049] In this way, by making the length of the structural plate less than the total thickness of the square cells on the same side, it is beneficial to ensure that the square cells will not squeeze the structural plate when they are squeezed into the box.

[0050] In some embodiments, the length of the structural plate is 10 to 40 mm shorter than the length of the corresponding battery pack.

[0051] In this way, the side lengths were maximized while ensuring that the square battery cells would not be squeezed into the structural plate when they were pressed into the box, which helps to ensure structural strength.

[0052] In some embodiments, the width of the structural plate is 60% to 100% of the length of the second surface.

[0053] In this way, by making the width of the structural plate 60% to 100% of the length of the second surface, it is beneficial to ensure that there is sufficient area on the structural plate for mounting the adhesive.

[0054] In some embodiments, the thickness of the structural plate is 1.0 to 3.0 mm.

[0055] Thus, the thickness of the structural plate is 1.0 to 3.0 mm, which ensures structural strength while also helping to reduce the gap between adjacent square cells.

[0056] In some embodiments, the battery pack further includes a structural plate stop, wherein the structural plate has two third sides on a third surface opposite to the second surface in a direction perpendicular to the first surface, and the structural plate stop is disposed on at least one of the third sides.

[0057] Thus, by setting structural plate stoppers on the structural plate, it is beneficial to prevent the adhesive from overflowing from the bonding area between the structural plate and the square battery cell to the rounded corners and other areas, achieving double protection.

[0058] In some embodiments, the structural plate stop is disposed on the two third sides.

[0059] In this way, by setting structural panel stoppers on both third sides of the structural panel, the side edges of the bonding area of ​​the structural panel are fully surrounded, preventing glue overflow to the greatest extent.

[0060] In some embodiments, the structural plate stop is a sealing foam.

[0061] Thus, by using adhesive-blocking foam as a stopper for the structural plate, its compressive elasticity is utilized to effectively block the adhesive and accommodate the gap between the structural plate and the square battery cell.

[0062] In some embodiments, the thickness of the adhesive-blocking foam after compression is 0.5 to 2 mm.

[0063] Thus, by limiting the thickness of the adhesive-resistant foam to 0.5–2 mm after compression, it is beneficial to ensure the thickness of the bonded parts.

[0064] In some embodiments, the multiple stops on the second surface of the same side of the multiple adjacent square cells can be a one-piece structure integrally formed.

[0065] In this way, by processing multiple stop components into a single piece, it is beneficial to improve production efficiency and assembly accuracy, ensure the consistency of the stop component layout, and reduce the cost of component management.

[0066] Additional aspects and advantages of embodiments of this application 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 embodiments of this application. Attached Figure Description

[0067] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments 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. Wherein: Figure 1 This is a partial structural schematic diagram of the battery pack according to an embodiment of this application; Figure 2 This is a schematic diagram of the battery pack according to an embodiment of this application; Figure 3 This is a schematic diagram of the structure of a square battery cell according to an embodiment of this application; Figure 4 This is a schematic diagram of the layout of the stop member in some embodiments of this application; Figure 5 This is a schematic diagram of the layout of the stop member in some embodiments of this application; Figure 6 This is a schematic diagram of the layout of the stop member in some embodiments of this application; Figure 7 This is a schematic diagram of the layout of the stop member in some embodiments of this application; Figure 8 This is a schematic diagram of the structure of the stop member according to some embodiments of this application; Figure 9 This is a partial structural schematic diagram of the battery pack according to an embodiment of this application; Figure 10 This is a structural schematic diagram of the structural plate according to an embodiment of this application.

[0068] Explanation of main component symbols: Battery pack 100, casing 10, battery group 20, square cell 21, first surface 211, second surface 212, first side 2121, second side 2122, rounded corner 213, adhesive 22, stop 23, first stop strip 231, second stop strip 232, stop film 233, buffer foam 30, fixing adhesive 40, structural plate 50, third surface 51, third side 52, structural plate stop 60, end plate 70. Detailed Implementation

[0069] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application. In the description of this application, it should be understood that the terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," etc., indicating orientation or positional relationships, are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as limiting this application. In the description of this application, "a plurality of" means two or more, unless otherwise explicitly specified.

[0070] In the description of this application, it should be noted that, unless otherwise expressly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection. They can refer to a mechanical connection or an electrical connection. They can refer to a direct connection or an indirect connection through an intermediate medium, and they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific circumstances.

[0071] In this application, unless otherwise expressly specified and limited, "above" or "below" the second feature can include direct contact between the first and second features, or contact between the first and second features through another feature between them. Furthermore, "above," "over," and "on top" of the second feature includes the first feature being directly above or diagonally above the second feature, or simply indicates that the first feature is at a higher horizontal level than the second feature. "Below," "below," and "under" the second feature includes the first feature being directly below or diagonally below the second feature, or simply indicates that the first feature is at a lower horizontal level than the second feature.

[0072] This disclosure provides many different embodiments or examples for implementing different structures of this application. To simplify the disclosure, specific examples of components and arrangements are described herein. Of course, these are merely examples and are not intended to limit the scope of this application. Furthermore, reference numerals and / or letters may be repeated in different examples; such repetition is for simplification and clarity and does not in itself indicate a relationship between the various embodiments and / or arrangements discussed. In addition, various specific examples of processes and materials are provided in this application, but those skilled in the art will recognize the application of other processes and / or the use of other materials.

[0073] The battery pack in this technology includes prismatic cells arranged in an array, with adhesive joints between adjacent rows and columns of cells. Specifically, the adhesive joints act on the rounded corners where the large and small faces of the prismatic cells meet. If the battery pack vibrates during use, the adhesive joints can compress the rounded corners. Since the rounded corners and small faces have small areas and are not easily deformed, this compression can cause deformation of the large faces. This could lead to mechanical fatigue due to frequent deformation, resulting in leakage and affecting the cycle life of the prismatic cells. Furthermore, the adhesive joints may overflow onto the large faces during use and solidify there. When the battery pack vibrates during use, the solidified adhesive joints can compress the large faces, causing lithium plating, which also affects the cycle life of the prismatic cells.

[0074] Please see Figure 1 The battery pack 100 of this application includes a plurality of square battery cells arranged in an array and an adhesive. The square battery cells include two opposing first surfaces and two opposing second surfaces. The first and second surfaces are adjacent and connected to each other. The area of ​​the first surface is larger than the area of ​​the second surface. The adhesive is disposed between the second surfaces of two adjacent square battery cells. The overlap area between the adhesive and the first surface is 0.

[0075] The battery pack 100 provided in this application allows adjacent square cells 21 to be fixedly connected by adhesive members 22, which restricts the adhesive members 22 from entering the first surface 211, preventing lithium plating caused by the adhesive members 22 pressing against the first surface 211. Instead, the adhesive members 22 are placed on the second surface 212. Because the second surface 212 has a smaller area, it has higher rigidity and is less prone to deformation, thus avoiding mechanical fatigue due to frequent deformation. Furthermore, the high rigidity of the second surface 212 ensures that most of the stress from the adhesive members 22 is confined to the surface itself and the surrounding shell 10 material. Stress is difficult to effectively penetrate the internal space of the square cell 21 and act on the electrode, thus preventing the formation of local high-voltage points that would obstruct lithium-ion transport. This prevents lithium plating caused by uneven pressure and ensures the cycle life of the square cells 21.

[0076] For details, please refer to Figures 1 to 3 In this embodiment of the application, the battery pack 100 includes a housing 10 and a plurality of battery packs 20 arranged in parallel. Each battery pack 20 includes a plurality of square cells 21 stacked along a direction perpendicular to the first surface 211. The battery packs 20 are installed inside the housing 10.

[0077] Furthermore, the battery pack 100 also includes a cushioning foam 30, which is disposed between the battery pack 20 and the housing 10 to fix the battery pack 20 and absorb vibration, thereby preventing the battery pack 20 from directly colliding with the housing 10 when subjected to vibration, which could damage the square cells 21 or the housing 10.

[0078] In this embodiment, a fixing adhesive 40 is provided on the bottom surface of the housing 10, and the battery pack 20 is bonded to the housing 10 by the fixing adhesive 40.

[0079] In some embodiments, the battery pack 20 may further include a liquid cooling assembly disposed at the bottom of the housing 10 and located between the battery pack 20 and the housing 10. The liquid cooling assembly is thermally coupled to the square cell 21 for heat dissipation of the square cell 21.

[0080] In this embodiment, the square cell 21 is rectangular, wherein the first surface 211 is the largest surface of the rectangular cell 21, and the second surface 212 is the smallest surface of the rectangular cell 21. The adhesive 22 and the stop 23 are both disposed on the second surface 212. Furthermore, during the production and assembly of the battery pack 100, the stop 23 is attached to the edge area of ​​the second surface 212 of the square cell 21.

[0081] In this embodiment, the square battery cell 21 further includes four rounded corner surfaces 213 connecting the first surface 211 and the second surface 212. The overlap area between the adhesive 22 and the rounded corner surfaces 213 is also 0, that is, the adhesive 22 does not enter the rounded corner surfaces 213 to avoid the adhesive 22 squeezing the rounded corner surfaces 213, which would cause the first surface 211 of the square battery cell 21 to rupture and leak liquid due to mechanical fatigue caused by frequent deformation.

[0082] In some embodiments, the adhesive 22 is a structural adhesive or a foam adhesive.

[0083] Thus, by using structural adhesive or foam adhesive as the bonding component 22, it is beneficial to select the bonding component 22 with corresponding strength, elasticity or weight characteristics according to different application requirements, so as to achieve a stable and reliable connection between the square cells 21.

[0084] Specifically, the adhesive component 22 can be made of structural adhesive or foam. Structural adhesives (such as epoxy resin adhesives and polyurethane adhesives) have high shear strength and peel strength, and are suitable for applications requiring high mechanical load-bearing capacity; foams (such as acrylic foams and polyurethane foams) have a certain degree of elasticity after curing, and can better absorb the volume changes and vibration impacts of the square battery cell 21.

[0085] It is important to note that when selecting the adhesive component 22, in addition to considering its mechanical properties, its bonding compatibility with the material of the square cell 21 housing 10 (usually aluminum or stainless steel) and the structural plate 50 material (such as epoxy board) is also necessary, as are its resistance to aging, high and low temperature cycling, and electrolyte resistance. The adhesive component 22 can be coated using methods such as dispensing, screen printing, or spraying, and its dosage and distribution must be precisely controlled to ensure bonding quality.

[0086] In some embodiments, the elastic modulus of the adhesive 22 is 10~1000 MPa. Thus, the adhesive possesses a certain degree of flexibility, effectively absorbing and dissipating impact energy and vibration.

[0087] In some embodiments, the battery pack further includes a stop 23 disposed between the second surfaces 212 of two adjacent square cells 21, the stop 23 being configured to prevent the adhesive 22 from entering the first surface 211.

[0088] Thus, the stopper 23 prevents the adhesive 22 from entering the first surface 211, thereby avoiding the adhesive 22 from squeezing the rounded corner surface 213, which would cause the first surface 211 of the square cell 21 to rupture and leak liquid due to mechanical fatigue caused by frequent deformation.

[0089] In this embodiment of the application, cushioning foam for buffering and fixing is also attached to the opposing first surfaces 211 of two adjacent square cells 21 located in the same battery pack 20. Furthermore, the cushioning foam is attached to the edge of the first surface 211. The cushioning foam includes two adhesive backing surfaces, which are respectively bonded to the first surfaces 211 of two adjacent square cells 21.

[0090] Please see Figures 3 to 7 In some embodiments, the second surface 212 includes two first side edges 2121 connected to the first surface 211, and the stop member 23 includes two first stop strips 231, each of which is disposed close to the corresponding first side edge 2121 and substantially parallel to the corresponding first side edge 2121.

[0091] Thus, by placing the foam strips on the two first sides 2121 adjacent to the first surface 211, it is beneficial to precisely block the adhesive 22 from flowing to the area of ​​the first surface 211 where stress concentration is most likely to occur.

[0092] Specifically, in this embodiment, the two first side edges 2121 are connected to the rounded corner surface 213, and the first stop strip 231 is a long rectangle, attached to the first side edge 2121 and parallel to the first side edge 2121.

[0093] Furthermore, in some embodiments, the length of the first stop bar 231 is 60% to 100% of the length of the first side 2121.

[0094] Thus, by limiting the length of the foam strip to 60% to 100% of the length of the second surface 212, it is beneficial to provide sufficient adhesive application area for the adhesive component 22 to ensure adhesive strength while ensuring effective adhesive blocking.

[0095] Specifically, in some embodiments, the first stop strip 231 may extend to almost the entire length of the first side 2121, with only a small amount of space reserved at both ends to avoid interference with other structures. This maximizes the prevention of adhesive flow to the rounded corner surface 213 while preserving sufficient effective area for the bonding region.

[0096] In some embodiments, the second surface 212 includes a second side 2122 connected to both ends of the two first sides 2121, and the stop member 23 includes a second stop strip 232 disposed close to one of the second sides 2122 and substantially parallel to the corresponding second side 2122.

[0097] Thus, by placing the foam strips on the two first sides 2121 adjacent to the rounded corner surface 213, it is beneficial to precisely block the adhesive 22 from flowing to the area of ​​the rounded corner surface 213 where stress concentration is most likely to occur.

[0098] Specifically, in this embodiment, the second stop bar 232 is the same as the first stop bar 231, and is generally rectangular. The arrangement direction of the second stop bar 232 is perpendicular to the first side 2121 and parallel to the second side 2122, and should be as close as possible to the edge of the second side 2122 so as to form a blocking boundary together with the first stop bar 231.

[0099] Please see Figures 3 to 7 In some embodiments, the second surface 212 includes a second side 2122 connected to both ends of the two first side 2121, and the stop member 23 includes two second stop bars 232, each second stop bar 232 being disposed close to the corresponding second side 2122 and substantially parallel to the corresponding second side 2122.

[0100] Thus, by providing stop strips on both second side edges 2122, it is beneficial to achieve more comprehensive enclosure of the adhesive 22, preventing it from overflowing from either side to the rounded corner surface 213 or the first surface 211, and ensuring the reliability of the blocking effect.

[0101] In some embodiments, the first stop bar 231 and the second stop bar 232 form a U-shape, an inverted U-shape, or a square shape on the second surface 212.

[0102] Thus, by arranging the stop strips in a U-shape, inverted U-shape, or square shape, it is beneficial to form a closed or semi-closed bonding area on the second surface 212, thereby more effectively confining the adhesive 22 within a predetermined range and preventing it from overflowing.

[0103] In some embodiments, the elastic modulus of the first stop bar 231 and / or the second stop bar 232 is 1-50 MPa.

[0104] Thus, using a first stop bar 231 and / or a second stop bar 232 with a low elastic modulus is beneficial for providing excellent shock absorption and damping effects for two adjacent square cells 21.

[0105] Specifically, in this embodiment, when the second side 2122 of the second surface 212 is provided with the second stop strip 232, it and the two first stop strips 231 can together form a rectangular frame structure with a square shape, which strictly confines the adhesive within a predetermined area inside the frame.

[0106] In some embodiments, one of the second stop strips 232 may be removed on one side to create an opening, forming a U-shaped or inverted U-shaped layout, or both second stop strips 232 may be completely removed to form an I-shaped layout. This facilitates the injection of structural adhesive or foam adhesive through the opening.

[0107] It should be noted that the specific layout of the first stop strip 231 and the second stop strip 232 can be selected based on the adhesive's fluidity and the application process, either on a single second side 2122 or on both second sides 2122. If the adhesive has low viscosity and high fluidity, it is recommended to arrange the second stop strip 232 on both sides to achieve full circumference coverage; if the adhesive is more viscous or high-precision application equipment is used, it is only necessary to place the stop strip on the side prone to adhesive overflow, thus simplifying the process and reducing costs while ensuring the adhesive blocking effect.

[0108] In some embodiments, the length of the second stop bar 232 is 60% to 100% of the length of the second side 2122.

[0109] Thus, by limiting the length of the foam strip set on the second side 2122 to 60% to 100% of the width of the second surface 212, it is beneficial to provide sufficient adhesive application area for the adhesive component 22 to ensure adhesive strength while ensuring effective adhesive blocking.

[0110] Specifically, in this embodiment, the length of the second stop strip 232 can be set according to the actual size of the second side 2122 and the bonding process requirements, and should generally account for 60% to 100% of the length of the second side 2122. For example, if the second side 2122 is short, it can be arranged in a continuous manner to achieve the best blocking effect; if the second side 2122 is long or the bonding area needs to avoid certain structures, the second stop strip 232 can be arranged in segments or its length can be appropriately shortened.

[0111] In some embodiments, the first stop bar 231 or the second stop bar 232 is made of foam strips.

[0112] Thus, by using foam strips as stoppers 23, it is beneficial to utilize their soft and compressible properties to adapt to the slight unevenness on the surface of the square battery cell 21, ensuring the stopping effect while avoiding additional rigid pressure on the square battery cell 21.

[0113] Specifically, in this embodiment, the stop 23 is preferably made of a foam material with certain elasticity and compressive strength, such as polyurethane foam or rubber foam. It is attached in strip form to the second surface 212 of the square cell 21 with adhesive backing, and is arranged adjacent to the first side 2121 where the rounded corner surface 213 intersects the second surface 212. In actual operation, the operator can first precisely attach the foam strip to the edge area of ​​the second surface 212 of the square cell 21, keeping it parallel to the first side 2121, to ensure that the adhesive does not spread beyond the stop strip to the rounded corner area after dispensing or applying glue. This foam strip not only serves as a physical barrier, but also, due to its compressibility, can adapt to the manufacturing tolerances and surface unevenness of the square cell 21 housing 10, thereby maintaining a stable adhesive-blocking effect throughout its entire life cycle. Furthermore, the foam material also has certain shock absorption and cushioning properties, which can further reduce the impact of external vibrations on the bonding interface and improve the overall structural reliability of the battery pack 100.

[0114] In some embodiments, in addition to foam, materials with a certain degree of flexibility, such as silicone strips, rubber strips, or plastic profiles, may be used as stoppers 23. These materials should have good electrolyte resistance and long-term compression set characteristics to adapt to the chemical environment and long-term mechanical stress inside the battery pack 100.

[0115] In some embodiments, the foam strip includes two adhesive backing surfaces, which are respectively bonded to the second surfaces 212 of two adjacent square battery cells 21.

[0116] Thus, by setting only one layer of foam strip between two adjacent square cells 21, it is beneficial to simplify the assembly process, reduce production costs, and ensure sufficient adhesive blocking effect.

[0117] In this embodiment, the foam strip can be designed with a double-sided adhesive structure. Specifically, both adhesive sides of the foam strip are coated with pressure-sensitive adhesive and covered with release paper. During assembly, the release paper on one side is first peeled off and the foam strip is pasted to a designated position on the second surface 212 of a square battery cell 21. Then, when stacking adjacent square battery cells 21, the release paper on the other side is peeled off and pasted onto the adjacent square battery cell 21, so that the two square battery cells 21 can achieve the dual functions of bonding and adhesive blocking through the same foam strip.

[0118] In some embodiments, the adhesives applied to the two adhesive surfaces should be acrylic adhesives with high adhesion and resistance to high temperature and humidity to ensure the reliability of bonding throughout the entire service life of the battery pack 100.

[0119] Please see Figures 3 to 7 In some embodiments, the foam strip is compressed between two adjacent square cells 21, and the thickness of the compressed foam strip is 0.5 to 2 mm.

[0120] Thus, by limiting the thickness of the compressed foam strip to 0.5 to 2 mm, it is beneficial to limit the thickness of the adhesive 22 to within 0.5 to 2 mm, so as to ensure that the adhesive 22 has the best mechanical properties.

[0121] In some embodiments, the compression rate of the foam strip is 45% to 55%. In this way, the foam strip can provide sufficient support while retaining ample cushioning space.

[0122] Specifically, in this embodiment, the foam strip is compressed after the square battery cells 21 are stacked and pressed together. Its compressed thickness should be controlled between 0.5 mm and 2 mm. This thickness range ensures that the adhesive forms a uniform and appropriately thick layer within the gap. When the adhesive 22 is a structural adhesive, its mechanical properties are optimal when its thickness is within 0.5 to 2 mm. If the adhesive layer is too thin, it may lead to insufficient bond strength; if it is too thick, it is prone to flow runaway and uneven stress distribution. By controlling the initial thickness and compression ratio of the foam strip, the final thickness of the adhesive can be indirectly and precisely managed. For example, if the target adhesive thickness is 1 mm, a foam strip with an initial thickness of 2 mm and a compression ratio of 50% can be selected, which will meet the design requirements after pressing. Furthermore, a uniform adhesive layer thickness also helps improve heat conduction between the square battery cells 21, enhancing the thermal management performance of the battery pack 100.

[0123] In some embodiments, an adhesive area is formed on the second surface 212, and an adhesive member 22 is located between the two first stop strips 231. The adhesive member 22 is disposed within the adhesive area 231, and the area of ​​the adhesive area is greater than 60% of the second surface 212.

[0124] In this way, by forming an adhesive area with an area greater than 60% of the area of ​​the second surface 212 by enclosing it with foam strips, it is ensured that the adhesive part 22 has sufficient adhesive area, while strictly limiting the glue application range to prevent glue overflow.

[0125] Specifically, in this embodiment, the bonding area formed by the first stop strip 231 and the second stop strip 232 on the second surface 212 should account for more than 60% of the total area of ​​the second surface 212 to ensure that the bonding strength meets the mechanical performance requirements of the module. This bonding area is typically located in the central region of the second surface 212, and its shape corresponds to the inner edge of the frame formed by the stop strips, generally being rectangular. When applying adhesive, the adhesive should completely fill this area, and the amount of adhesive should be appropriate.

[0126] In some embodiments, the area of ​​the bonding area can be changed by adjusting the distance of the stop strip from the edge. For example, if a larger bonding area is required, the stop strip can be arranged as close as possible to the outer edge of the second surface 212; if a wider adhesive barrier is required, the stop strip can be moved inward, but it must be ensured that the area of ​​the bonding area always meets the minimum ratio requirement.

[0127] Please see Figure 8 In some embodiments, the battery pack 100 includes at least two battery groups 20, each battery group 20 including a plurality of square cells 21 stacked and aligned along a direction perpendicular to the first surface 211, and adjacent battery groups 20 arranged along a direction perpendicular to the second surface 212; the stop member 23 is a stop film 233, which is disposed between adjacent battery groups 20; the stop film 233 has a plurality of hollowed-out adhesive areas, and the orthographic projection of each adhesive area on the square cell 21 is located within the range of the second surface 212, and the adhesive member 22 is disposed within the adhesive area 231.

[0128] Thus, by using a stop film 233 covering the entire battery pack 20 and opening multiple aligned hollow bonding areas, it is beneficial to achieve uniform and precise adhesive application to the second surface 212 of all square cells 21, which greatly improves the efficiency and consistency of mass production, while avoiding the tedious process of pasting stop strips one by one.

[0129] Specifically, in some embodiments, for ease of installation, the stop 23 can also be configured as a stop film 233. The stop film 233 has multiple pre-formed perforated bonding areas, the position and size of which are precisely aligned with the second surface 212 of the individual square battery cell 21.

[0130] During assembly, the stop film 233 is first attached to the square battery cell 21, and then adhesive is applied through the hollowed-out bonding area.

[0131] In some embodiments, the barrier membrane 233 is made of PEC or PC.

[0132] Thus, by using PET film or PC film as the stop 23, the adhesive 22 can be effectively isolated by utilizing its smoothness, high strength and chemical resistance, and a thin and highly rigid adhesive-blocking solution is provided.

[0133] Specifically, in some embodiments, the barrier film 233 can be selected from PET (polyethylene terephthalate) film or PC (polycarbonate) film, because it has high tensile strength and tear strength, and can effectively resist the extrusion and penetration of adhesives. Among them, PET film has lower cost and excellent chemical stability and insulation; PC film has better toughness and strong impact resistance.

[0134] In some embodiments, the thickness of the barrier film 233 is 0.015 to 0.5 mm.

[0135] Thus, by limiting the thickness of the PET or PC film to 0.015 to 0.5 mm, it is beneficial to minimize additional weight and space occupation while ensuring sufficient mechanical strength to block the adhesive 22.

[0136] Specifically, in some embodiments, the thickness of the stop film 233 is generally selected to be between 0.015 mm and 0.5 mm. If it is too thin, it is easy to tear during operation, while if it is too thick, it lacks flexibility and increases unnecessary weight and volume.

[0137] In some embodiments, the barrier film 233 may be coated with a weakly tacky adhesive 22, allowing it to be temporarily fixed to the surface of the square battery cell 21, but which can be relatively easily peeled off when maintenance is required. Furthermore, the film surface may be matte-finished to avoid glare interference during visual inspection.

[0138] In some embodiments, the bonding area is a rectangular area aligned with the second surface 212, the length of the bonding area is 60% to 95% of the length of the second surface 212, and the width of the bonding area is 60% to 90% of the width of the second surface 212.

[0139] Thus, by limiting the length and width of the opening to specific proportions of the length and width of the second surface 212, it is beneficial to ensure that the bonding area is large enough to provide a solid bond, while leaving a sufficiently wide retaining edge around the perimeter to prevent glue overflow.

[0140] Specifically, in some embodiments, the perforated bonding area on the stop film 233 is typically designed as a rectangle. The length of the bonding area should account for 60% to 95% of the length of the second surface 212, and the width should account for 60% to 90% of its width. For example, for a square battery cell 21 with a second surface 212 size of 100mm × 50mm, the bonding area size can be designed to be 80mm long and 40mm wide, with a 10mm wide adhesive-blocking edge around the perimeter. The width of this adhesive-blocking edge needs to be determined based on the fluidity of the adhesive and the application precision. For adhesives with high fluidity, the adhesive-blocking edge should be appropriately widened; for paste-like adhesives or adhesives using a sealing ring type applicator, the width of the adhesive-blocking edge can be appropriately reduced to increase the bonding area.

[0141] Please see Figure 9 and Figure 10 In some embodiments, the battery pack 100 further includes a structural plate 50 disposed between two adjacent battery packs 20, and an adhesive 22 disposed between the structural plate 50 and the battery packs 20 and configured to adhesive the structural plate 50 to the second surface 212.

[0142] Thus, by placing the adhesive 22 between the structural plate 50 and the second surface 212, a reliable connection between the square cell 21 and the structural plate 50 is achieved, which helps to enhance the overall structural strength of the battery pack 100.

[0143] Specifically, in some embodiments, the battery pack 100 may also include a structural plate 50, which is disposed between two adjacent battery packs 20 to provide structural support and connection.

[0144] In some embodiments, adhesive members 22 are provided on both sides of the structural plate 50. The adhesive on one side is bonded to the second surface 212 of all the square cells 21 in one module, and the other side can be connected to the second surface 212 of all the square cells 21 in another module. The structural plate 50 can significantly enhance the overall rigidity and vibration and impact resistance of the battery pack 100.

[0145] In some embodiments, the edges of the structural plate 50 should be smooth and burr-free, and all corners should be chamfered or rounded to avoid scratching the coating of the square cell 21 or the operator during assembly.

[0146] In some embodiments, the structural plate 50 is an insulating plate.

[0147] Furthermore, in some embodiments, the structural plate 50 is an epoxy resin plate.

[0148] Thus, by using epoxy resin boards to make structural panels 50, it is beneficial to utilize their high strength, high rigidity and excellent insulation properties to meet the structural and safety requirements of the battery pack 100.

[0149] Specifically, in some embodiments, the structural plate 50 may be made of epoxy resin board. Epoxy resin has high mechanical strength, high rigidity, excellent dimensional stability and electrical insulation properties, as well as good electrolyte resistance and flame retardancy. Furthermore, the epoxy resin board can also be reinforced by adding glass fiber cloth to form an FR-4 type composite material, whose flexural strength and modulus can meet the structural requirements of the battery pack 100.

[0150] Please see Figure 9 and Figure 10 In some embodiments, the length of the structural plate 50 is less than the length of the corresponding battery pack 20.

[0151] Specifically, in some embodiments, the length of the structural plate 50 is 10 to 40 mm shorter than the length of the corresponding battery pack 20.

[0152] In this way, while ensuring that the square battery cell 21 does not compress the structural plate 50 when it is pressed into the box, the length of the side is selected to the maximum extent, which helps to ensure the structural strength.

[0153] In some embodiments, the structural plate 50 should be slightly shorter in length than the total length of the battery pack 20 to which it is bonded, typically 10mm to 40mm shorter than the module length. This dimensional difference allows for the volume expansion of the square cells 21 during charging and discharging, as well as the assembly tolerances when the module is installed in the housing, preventing interference between the ends of the structural plate 50 and the housing or other rigid structures, thereby avoiding additional compressive stress on the square cells 21. For example, if a module is composed of 10 stacked square cells 21 with a total thickness of 200mm, the length of the structural plate 50 can be designed to be 180mm, leaving a 10mm gap at each end when it is centrally positioned in the module.

[0154] In some embodiments, the width of the structural plate 50 is 60% to 100% of the length of the second surface 212.

[0155] Thus, by making the width of the structural plate 50 60% to 100% of the length of the second surface 212, it is beneficial to ensure that there is a sufficient area on the structural plate 50 for setting the adhesive 22.

[0156] Specifically, in some embodiments, the width of the structural plate 50 should cover the second surface 212 of the square cell 21 as much as possible, typically 60% to 100% of its width. Preferably, the width of the structural plate 50 should be greater than 90% of the length of the second surface 212 to provide maximum bonding area and structural support effect.

[0157] In some embodiments, if the width of the structural plate 50 is smaller than the width of the second surface 212, it should be ensured to be centered so that the exposed square cell 21 surface areas on both sides are symmetrical, thereby maintaining a balanced force.

[0158] In some embodiments, the thickness of the structural plate 50 is 1.0 to 3.0 mm.

[0159] Thus, the thickness of the structural plate 50 is 1.0 to 3.0 mm, which ensures structural strength while also helping to reduce the gap between adjacent square cells 21.

[0160] Specifically, in some embodiments, the thickness of the structural plate 50 needs to be as thin as possible while ensuring rigidity and strength, in order to reduce the overall volume and weight of the battery pack 100. Typically, its thickness is designed to be between 1.0 mm and 3.0 mm. For smaller battery packs 100 or applications with less stress, a plate thinner than 1.0 mm can be selected; for larger battery packs 100 or applications requiring high structural rigidity, a plate thicker than 2.0 mm can be selected.

[0161] In some embodiments, the choice of material also affects the thickness; for example, when using carbon fiber reinforced composite materials, a thinner thickness can achieve the same mechanical properties as a thicker glass fiber reinforced plate.

[0162] Please see Figure 9 and Figure 10 In some embodiments, the battery pack 100 further includes a structural plate stop 60, on which two third sides 52 are provided on the third surface 51 of the structural plate 50 opposite to the second surface 212 in a direction perpendicular to the first surface 211, and the structural plate stop 60 is disposed on at least one third side 52.

[0163] Thus, by setting the structural plate stop 60 on the structural plate 50, it is beneficial to prevent the adhesive 22 from overflowing from the adhesive area between the structural plate 50 and the square cell 21 to the rounded corner surface 213 and other places, thus achieving double protection.

[0164] In some embodiments, the structural plate stop 60 is provided on the two third sides 52.

[0165] Thus, by providing structural plate stoppers 60 on both third sides 52 of the structural plate 50, the sides of the bonding area of ​​the structural plate 50 are fully surrounded, preventing glue overflow to the greatest extent.

[0166] Specifically, in some embodiments, to further prevent adhesive from overflowing from the bonding interface between the structural plate 50 and the square battery cell 21, a structural plate stop 60 may be provided on the third surface 51 opposite to the square battery cell 21. This stop 23 is typically arranged on the edge of the third surface 51, especially on the two third sides 52 perpendicular to the axis of the rounded corner surface 213 of the square battery cell 21.

[0167] Preferably, in some embodiments, structural plate stoppers 60 can be arranged on both third sides 52 of the structural plate 50 to achieve full-edge blocking. The two stoppers 23 can be parallel to each other and maintain a certain distance from the edge of the structural plate 50 to allow space for adhesive diffusion while still effectively preventing flow to the rounded corner area. The stoppers 23 can be continuous strips or segmented, but their total length should cover most of the third side 52.

[0168] In some embodiments, the structural plate stop 60 is a sealing foam.

[0169] Thus, by using adhesive-blocking foam as the structural plate stop 60, its compressive elasticity is utilized to effectively block the adhesive 22 and accommodate the gap between the structural plate 50 and the square battery cell 21.

[0170] Specifically, in some embodiments, the structural plate stop 60 may be made of adhesive-resistant foam, and its material properties are similar to those of the foam strips used on the square battery cell 21, requiring good compressibility, resilience, and chemical resistance. The cross-sectional shape of the foam is usually rectangular, but it can also be circular or semi-circular to better adapt to the geometry of the edge of the structural plate 50.

[0171] In some embodiments, the adhesive-blocking foam can be directly adhered to the surface of the structural plate 50 through its adhesive backing layer, or it can be designed as a plastic base with a slot. The base is first fixed to the structural plate 50, and then the adhesive-blocking foam is embedded in the slot. This method is more convenient for replacement and adjustment.

[0172] In some embodiments, the thickness of the adhesive-blocking foam after compression is 0.5–2 mm.

[0173] Thus, by limiting the thickness of the adhesive-blocking foam to 0.5–2 mm after compression, it is beneficial to ensure the thickness of the adhesive component 22.

[0174] Specifically, in some embodiments, the adhesive-resistant foam should be compressed after the structural plate 50 and the square battery cell 21 are pressed together, and its compressed thickness is recommended to be controlled between 0.5 mm and 2 mm, which matches the target thickness of the adhesive.

[0175] Please see Figure 8 In some embodiments, the multiple stops 23 on the second surface 212 of multiple adjacent square cells 21 located on the same side can be an integral structure formed by one-piece processing.

[0176] In this way, by processing multiple stop parts 23 into one piece, it is beneficial to improve production efficiency and assembly accuracy, ensure the consistency of the layout of the stop parts 23, and reduce the cost of parts management.

[0177] Specifically, in some embodiments, taking the stopper 23 as an example of a stopper film 233, an integrated stopper film 233 can be used for a battery pack 20 containing multiple square cells 21. The stopper 23 has multiple hollowed-out adhesive areas corresponding to the second surface 212 of each square cell 21. During installation, the entire stopper film 233 only needs to be aligned with all the square cells 21 on one side of the module and then pasted or snapped in place at once, avoiding the tedious work of pasting the stopper 23 one by one.

[0178] Please see Figure 9 In some embodiments, the battery pack 100 includes a plurality of square cells 21 stacked along a direction perpendicular to the first surface 211. The battery pack 100 also includes an end plate 70, which is attached to the first surface 211 of the square cells 21 located at both ends of the direction perpendicular to the first surface 211 away from the other square cell 21.

[0179] Thus, by providing end plates 70 on the first surface 211 of the square cells 21 at both ends, the adhesive 22 can be prevented from flowing onto the first surface 211 of the square cells 21 at both ends.

[0180] Specifically, in this embodiment, the end plate 70 is attached to the first surface 211 of the outermost square cell 21 to prevent the adhesive from accidentally flowing onto the first surface 211 of the end square cell 21 during module assembly, thereby avoiding contamination of the first surface 211 and potential damage to the first surface 211 by the adhesive 22.

[0181] In some embodiments, the end plate 70 is a foamed polypropylene and polycarbonate composite material plate.

[0182] Thus, by using foamed polypropylene and polycarbonate composite material to make end plate 70, it is beneficial to achieve lightweight and high rigidity of end plate 70, while its good buffering and energy absorption characteristics can better absorb and disperse impact energy.

[0183] Specifically, in some embodiments, the end plate 70 may be made of a composite material of expanded polypropylene (EPP) and polycarbonate (PC). Expanded polypropylene provides lightweight and excellent cushioning and energy absorption properties, while polycarbonate provides surface stiffness and strength. The two materials can be compounded by co-extrusion or lamination to form a lightweight sheet material that combines toughness and rigidity.

[0184] In some embodiments, the thickness of the end plate 70 can be designed according to the overall rigidity and impact resistance requirements of the module, typically between 5 mm and 20 mm. The inner surface of the end plate 70 (the surface in contact with the square cell 21) may have an adhesive layer or be designed with a snap-fit ​​structure to securely connect to the square cell 21.

[0185] In the description of this specification, the references to "certain embodiments," "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples" refer to specific features, structures, materials, or characteristics described in connection with the described embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0186] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of the stated features. In the description of this application, "multiple" means at least two, such as two or three, unless otherwise explicitly specified.

[0187] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. A battery pack, characterized in that, include: Multiple square battery cells arranged in an array, each square battery cell comprising two opposing first surfaces and two opposing second surfaces, the first surfaces and the second surfaces being adjacent and connected to each other, the area of ​​the first surface being larger than the area of ​​the second surface; An adhesive is disposed between the second surfaces of two adjacent square battery cells; the overlap area between the adhesive and the first surface is 0.

2. The battery pack according to claim 1, characterized in that, The adhesive is a structural adhesive or a foam adhesive.

3. The battery pack according to claim 1, characterized in that, The elastic modulus of the adhesive is 10~1000MPa.

4. The battery pack according to claim 1, characterized in that, The battery pack also includes a stop member disposed between the second surfaces of two adjacent square cells, the stop member being configured to prevent the adhesive from entering the first surface.

5. The battery pack according to claim 4, characterized in that, The second surface includes two first sides connected to the first surface, and the stop includes two first stop strips, each of which is disposed close to the corresponding first side and substantially parallel to the corresponding first side.

6. The battery pack according to claim 5, characterized in that, The length of the first stop bar is 60% to 100% of the length of the first side.

7. The battery pack according to claim 5, characterized in that, The second surface includes a second side connected to both ends of the two first sides, and the stop includes a second stop strip disposed near one of the second sides and substantially parallel to the corresponding second side.

8. The battery pack according to claim 5, characterized in that, The second surface includes a second side connected to both ends of the two first sides, and the stop includes two second stop bars, each of which is disposed close to and substantially parallel to the corresponding second side.

9. The battery pack according to claim 7, characterized in that, The length of the second stop bar is 60% to 100% of the length of the second side.

10. The battery pack according to claim 9, characterized in that, The first stop bar and the second stop bar form a U-shape, an inverted U-shape, or a square shape on the second surface.

11. The battery pack according to claim 7, characterized in that, The elastic modulus of the first stop bar and / or the second stop bar is 1-50 MPa.

12. The battery pack according to claim 7, characterized in that, The first or second stop strip is made of foam strip.

13. The battery pack according to claim 12, characterized in that, The foam strip includes two adhesive backing surfaces, which are respectively bonded to the second surface of two adjacent square battery cells.

14. The battery pack according to claim 12, characterized in that, The foam strip is compressed between two adjacent square battery cells, and the thickness of the compressed foam strip is 0.5 to 2 mm.

15. The battery pack according to claim 12, characterized in that, The compression rate of the foam strip is 45% to 55%.

16. The battery pack according to claim 5, characterized in that, An adhesive area is formed on the second surface, the adhesive area is located between the two first stop strips, the adhesive element is disposed in the adhesive area, and the area of ​​the adhesive area is greater than 60% of the second surface.

17. The battery pack according to claim 4, characterized in that, The battery pack includes at least two battery groups, each battery group including a plurality of square cells stacked and aligned along a direction perpendicular to the first surface, with adjacent battery groups arranged along a direction perpendicular to the second surface; The stop is a stop film, and the stop film is disposed between two adjacent battery packs; The stop film has multiple hollowed-out bonding areas, and the orthographic projection of each bonding area on the square battery cell is located within the range of the second surface. The adhesive is disposed within the bonding area.

18. The battery pack according to claim 17, characterized in that, The barrier membrane is made of PEC or PC.

19. The battery pack according to claim 17, characterized in that, The thickness of the barrier film is 0.015 to 0.5 mm.

20. The battery pack according to claim 17, characterized in that, The bonding area is a rectangular region aligned with the second surface. The length of the bonding area accounts for 60% to 95% of the length of the second surface, and the width of the bonding area accounts for 60% to 90% of the width of the second surface.

21. The battery pack according to claim 17, characterized in that, The battery pack also includes a structural plate disposed between two adjacent battery packs, and the adhesive is disposed between the structural plate and the battery packs and configured to adhesive the structural plate to the second surface.

22. The battery pack according to claim 21, characterized in that, The structural plate is an insulating plate.

23. The battery pack according to claim 21, characterized in that, The length of the structural plate is less than the length of the corresponding battery pack.

24. The battery pack according to claim 21, characterized in that, The length of the structural plate is 10 to 40 mm shorter than the length of the corresponding battery pack.

25. The battery pack according to claim 21, characterized in that, The width of the structural plate is 60% to 100% of the length of the second surface.

26. The battery pack according to claim 21, characterized in that, The thickness of the structural plate is 1.0 to 3.0 mm.

27. The battery pack according to claim 21, characterized in that, The battery pack also includes a structural plate stop, and the structural plate has two third side edges on a third surface opposite to the second surface along a direction perpendicular to the first surface. The structural plate stop is disposed on at least one of the third side edges.

28. The battery pack according to claim 27, characterized in that, The structural plate stop is provided on the two third sides.

29. The battery pack according to claim 27, characterized in that, The structural plate stop is made of adhesive-resistant foam.

30. The battery pack according to claim 29, characterized in that, The thickness of the adhesive-blocking foam after compression is 0.5–2 mm.

31. The battery pack according to any one of claims 4-29, characterized in that, The multiple adjacent square cells located on the same side of the second surface and the multiple stop members can be a one-piece structure integrally formed.

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