battery

Abstract

The application provides a battery, which comprises a battery cell and a packaging body for packaging the battery cell, the packaging body comprising a containing area and a sealing area for sealing the containing area, and the battery cell is located in the containing area; the packaging body comprises a first adhesive layer and a heat-sealing layer connected with each other, the packaging body has a first side and a second side, the heat-sealing layer of the first side of the sealing area is connected with the heat-sealing layer of the second side of the sealing area, the thickness of the first adhesive layer of the first side of the sealing area is T1, the thickness of the first adhesive layer of the second side of the sealing area is T2, and the sum of the thicknesses of the heat-sealing layer of the first side and the heat-sealing layer of the second side of the sealing area is T3, T3 < T1 + T2. The application can improve the service life and other performances of the battery.

Description

Technical Field

[0001] This invention relates to the field of electrochemical energy storage devices, and more specifically to a battery. Background Technology

[0002] Currently, increasingly stringent requirements are being placed on battery performance, including cycle life and other properties. For example, low-voltage (e.g., 12V, 48V) automotive systems offer advantages such as low cost, reduced fuel consumption in gasoline vehicles, and improved safety in new energy vehicles. Batteries used in low-voltage systems (e.g., lithium-ion rechargeable batteries) typically require excellent rate performance and cycle life (e.g., over 8 years). Therefore, the lifespan and other performance characteristics of existing batteries need further improvement. Summary of the Invention

[0003] This invention provides a battery that can improve battery life and other performance characteristics, effectively overcoming the shortcomings of existing technologies.

[0004] This invention provides a battery, including a battery cell and a package for encapsulating the battery cell. The package includes a receiving area and a sealing area that closes the receiving area, with the battery cell located within the receiving area. The package includes a first adhesive layer and a heat-sealing layer connected together. The package has a first side and a second side. The heat-sealing layer on the first side of the sealing area is connected to the heat-sealing layer on the second side of the sealing area. The thickness of the first adhesive layer on the first side of the sealing area is T1, and the thickness of the first adhesive layer on the second side of the sealing area is T2. In the sealing area, the sum of the thicknesses of the heat-sealing layer on the first side and the heat-sealing layer on the second side is T3, where T3 < T1 + T2.

[0005] According to one embodiment of the present invention, 10μm≤(T1+T2)-T3≤60μm; and / or, T1 is 18μm~66μm; and / or, T2 is 18μm~66μm; and / or, T3 is 20μm~90μm.

[0006] According to one embodiment of the present invention, the first adhesive layer on the first side of the sealing area and the first adhesive layer on the second side of the sealing area are integrally formed.

[0007] According to one embodiment of the present invention, the first adhesive layer comprises an acid-modified polypropylene layer; and / or, the heat-sealing layer comprises a polypropylene layer.

[0008] According to one embodiment of the present invention, the package further includes a first support layer, a third adhesive layer, a second support layer, a second adhesive layer, and a metal layer, wherein the first support layer, the third adhesive layer, the second support layer, the second adhesive layer, the metal layer, the first adhesive layer, and the heat-sealing layer are stacked.

[0009] According to one embodiment of the present invention, the first support layer comprises a polyester layer; and / or, the second support layer comprises a nylon layer; and / or, the metal layer comprises an aluminum layer; and / or, the roughness of the side of the metal layer facing the second adhesive layer is greater than the roughness of the side of the metal layer facing the first adhesive layer.

[0010] According to one embodiment of the present invention, the thickness of the package is greater than 90 μm.

[0011] According to one embodiment of the present invention, the thickness of the sealing area is 210μm to 260μm; and / or, the width of the sealing area is greater than or equal to 2mm.

[0012] According to one embodiment of the present invention, the battery cell is a battery cell with a capacity of less than 30Ah; and / or, the ratio of the thickness of the battery cell to the capacity of the battery cell is less than 4mm / Ah.

[0013] According to one embodiment of the present invention, the volume of the battery cell is 240 cm³. 3 ~302cm 3 ; and / or, the length of the battery cell is 100mm to 250mm, and / or, the width of the battery cell is 80mm to 150mm, and / or, the thickness of the battery cell is 3mm to 15mm.

[0014] The battery provided by this invention has a heat-sealing layer and a first adhesive layer adjacent to the heat-sealing layer. The heat-sealing layer on the first side and the heat-sealing layer on the second side of the sealing area (sealing edge) are connected to seal the accommodating area, thereby encapsulating the battery cell. By controlling T3 < T1 + T2, the heat-sealing layer connection part of the sealing area has a relatively small cross-sectional area, while the connection part has a relatively large cross-sectional area relative to the first adhesive layers on both sides. While sealing the accommodating area through the heat-sealing layer, the cross-sectional area of ​​the heat-sealing layer connection part on the first side and the second side can be reduced, reducing the entry of components such as moisture into the accommodating area. At the same time, the combination of the heat-sealing layer connection part and the first adhesive layers on both sides improves the sealing strength and stability of the encapsulation body, thereby maintaining the battery's long-term excellent power performance, cycle life, and safety performance, and improving the battery's service life, specifically up to 8 years or even more than 12 years. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of a battery structure according to an embodiment of the present invention;

[0016] Figure 2 for Figure 1 A schematic diagram of the cross-section of region Q1 in the diagram;

[0017] Figure 3 This is a schematic diagram of the cell structure of a battery according to an embodiment of the present invention;

[0018] Figure 4 This is a cross-sectional schematic diagram of the connection structure between the first inner tab and the first tab portion of a battery according to an embodiment of the present invention.

[0019] Figure 5 for Figure 1 A schematic diagram of the cross-section of region Q2 in the diagram;

[0020] Figure 6 This is a schematic diagram of the stacked structure of the positive electrode, separator, and negative electrode of a battery according to an embodiment of the present invention.

[0021] Figure 7 This is a schematic diagram of the battery structure when the package is not heat-sealed according to an embodiment of the present invention;

[0022] Figure 8 This is a schematic diagram of the battery structure after heat sealing of the package according to an embodiment of the present invention;

[0023] Figure 9 This is a structural electron microscope image of the package used in an embodiment of the present invention.

[0024] Explanation of reference numerals in the attached drawings: 11: Top sealing edge; 12: Side sealing edge; 10: Sealing area; 20: Non-sealing area; 110: Receiving area; 111: First side; 1111: First main body area; 1112: First fusion area; 112: Second side; 1121: Second main body area; 1122: Second fusion area; 101: Heat-sealing layer; 102: First adhesive layer; 103: Metal layer; 104: Second adhesive layer; 105: Second support layer; 106: Third adhesive layer; 107: First support layer; 108: Connecting layer; 2: Battery cell; 21: First... 1. First electrode ear; 211: First internal portion; 212: First external portion; 100: First inner electrode ear; 210: Connection portion between the first electrode ear and the first inner electrode ear; 22: Second electrode ear; 200: Second inner electrode ear; 220: Connection portion between the second electrode ear and the second inner electrode ear; 201: First electrode plate; 2011: First sub-electrode ear; 202: Second electrode plate; 2021: Second sub-electrode ear; 23: Protective adhesive layer; 3: Diaphragm; 30: Notch; 31: Third side portion; 32: Bending portion; 310: First region; 320: Second region; w 10 : Width of the sealed area; T 10 : Thickness of the sealing area; T1, T2, T3: Thickness; T0: Thickness of the package; Q1, Q2: Region. Detailed Implementation

[0025] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below. The specific embodiments listed below are merely descriptions of the principles and features of the present invention, and the examples are only for explaining the present invention and are not intended to limit the scope of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0026] In the description of this invention, unless otherwise explicitly specified and limited, terms such as "located at," "connected," and "connected" 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, an electrical connection, or a communication connection (network connection); they can refer to a direct connection, an indirect connection through an intermediate medium, or an internal connection between two components. Those skilled in the art can understand the specific meanings of the above within the context of this invention based on the specific circumstances. Furthermore, terms such as "first," "second," and "third" are used for descriptive purposes only, such as distinguishing components to more clearly illustrate / explain the technical solution, and should not be construed as indicating or implying the number of indicated technical features or a substantially significant order thereof.

[0027] This invention provides a battery, such as... Figures 1 to 8 As shown, the battery includes a cell 2 and a package containing the cell 2. The package includes a receiving area 110 and a sealing area 10 that closes the receiving area 110. The cell 2 is located within the receiving area 110. The package includes a first adhesive layer 102 and a heat-sealing layer 101 connected together. The package has a first side 111 and a second side 112. The heat-sealing layer 101 of the first side 111 of the sealing area 10 is connected to the heat-sealing layer 101 of the second side 112 of the sealing area 10. The thickness of the first adhesive layer 102 of the first side 111 of the sealing area 10 is T. 1. The thickness of the first adhesive layer 102 of the second side 112 of the sealing area 10 is T2. In the sealing area 10, the sum of the thicknesses of the heat-sealing layer 101 of the first side 111 and the heat-sealing layer 101 of the second side 112 is T3. That is, the distance from the side of the heat-sealing layer 101 of the first side 111 of the sealing area 10 facing the first adhesive layer 102 of the first side 111 to the side of the heat-sealing layer 101 of the second side 112 of the sealing area 10 facing the first adhesive layer 102 of the second side 112 of the sealing area 10 is T3, and T3 < T1 + T2.

[0028] In this way, the connection portion (hereinafter, the connecting layer 108) of the heat-sealing layer 101 between the first side 111 and the second side 112 of the sealing area 10 can have a relatively small cross-sectional area. While sealing the accommodating area 110 through the heat-sealing layer 101, it reduces the entry of moisture and other components into the accommodating area 110. At the same time, the first adhesive layers 102 located on opposite sides of the connection portion of the heat-sealing layer 101 have a relatively large cross-sectional area. By combining the first adhesive layers 102 located on opposite sides of the connection portion of the heat-sealing layer 101, the sealing strength of the sealing area 10 is improved. This technology improves the battery's strength and structural stability, maintaining its excellent power performance, cycle life, and safety over the long term, and extending its lifespan to 8 years or even more than 12 years. After 8 or 12 years of storage and use, the battery's encapsulation strength, capacity retention rate, and power performance degradation are reduced. Through simulation, after 12 years of storage and use, the capacity loss caused by storage is no more than 10.5%, the capacity loss caused by cycling is no more than 6.4%, and the capacity retention rate is no less than 83.1%, demonstrating significant effectiveness.

[0029] Specifically Figure 7 This is a schematic diagram of the package structure before heat sealing. Figure 8 This is a schematic diagram of the battery structure after heat sealing of the package, as shown below. Figure 7 and Figure 8 As shown, the first side portion 111 includes a first main body area 1111 and a first fusion area 1112 connected together. The first main body area 1111 is the area of ​​the first side portion 111 corresponding to the receiving area 110 (i.e., the first main body area 1111 is the part of the first side portion 111 corresponding to the receiving area 110). The first fusion area 1112 is the first side portion 111 of the sealing area 10 (i.e., the first fusion area 1112 is the part of the first side portion 111 located in the sealing area 10). The second side portion 112 includes a second main body area 1121 and a second fusion area 1122 connected together. The second main body area 1121 is the area of ​​the second side portion 112 corresponding to the receiving area 110 (i.e., the second main body area 1121 is the part of the second side portion 112 corresponding to the receiving area 110). The second side 112 corresponds to the portion of the receiving area 110. The second fusion area 1122 is the second side 112 of the sealing area 10 (i.e., the second fusion area 1122 is the portion of the second side 112 located in the sealing area 10). The first main body area 1111 and the second main body area 1121 are located on opposite sides of the battery cell 2. The first fusion area 1112 and the second fusion area 1122 are connected, specifically, the heat sealing layer 101 of the first fusion area 1112 and the heat sealing layer 101 of the second fusion area 1122 are connected (i.e., the heat sealing layer 101 of the first side 111 of the sealing area 10 is connected to the heat sealing layer 101 of the second side 112 of the sealing area 10) to seal the receiving area 110.

[0030] Figure 2 for Figure 1A cross-sectional schematic diagram of region Q1 (i.e., the region without protruding tabs) is shown in the image. Figure 2 The heat-sealing layer 101 of the first side 111 of the sealing area 10 and the heat-sealing layer 101 of the second side 112 of the sealing area 10 can be bonded together and generally can be combined into one, that is, the two are fused into one layer to form a connecting layer 108.

[0031] Specifically, the heat-sealing layer 101 can be used to heat-seal the package to form a sealing edge. In a specific implementation, the first fusion region 1112 and the second fusion region 1122 can be heat-sealed at a high temperature. During the heat-sealing process, the heat-sealing layer 101 of the first fusion region 1112 and the heat-sealing layer 101 of the second fusion region 1122 melt and fuse together, thereby becoming a composite layer (i.e., composited into one, forming a connecting layer 108) to seal the accommodating region 110 and realize the encapsulation of the battery.

[0032] The thickness of the connecting layer 108 is T3. By controlling T3 < T1 + T2, the connecting layer 108 can have a relatively small thickness, i.e., a relatively small cross-sectional area (the cross-section parallel to the thickness direction of the connecting layer 108), while achieving heat sealing of the accommodating area 110. This reduces the penetration of components such as moisture into the accommodating area 110. At the same time, combined with the first adhesive layers 102 located on opposite sides of the connecting layer 108 (i.e., the first adhesive layer 102 on the first side 111 and the first adhesive layer 102 on the second side 112), the sealing strength and structural stability of the sealing area 10 can be improved, thereby improving the battery's lifespan and other performance characteristics.

[0033] The thickness direction of the connecting layer 108, the thickness direction of the sealing area 10, the direction along the first side 111 of the sealing area 10 to the second side 112 of the sealing area 10, and the thickness direction of the battery or cell 2 are parallel to each other.

[0034] Specifically, such as Figure 1 As shown, the package includes sealing edges, which typically include a top sealing edge 11 located on one side of the cell 2 in a first direction and side sealing edges 12 located on opposite sides of the cell 2 in a second direction. The sealing area 10 is the effective sealing area of ​​the sealing edges, that is, the sealing area 10 is the area where the heat-sealing layer 101 of the first side 111 and the heat-sealing layer 101 of the second side 112 are connected. The orthographic projection of the sealing area 10 and the connecting layer 108 formed by the fusion of the heat-sealing layer 101 of the first side 111 and the heat-sealing layer 101 of the second side 112 substantially overlaps. The orthographic projection refers to the projection of the sealing area 10 and the connecting layer 108 along a third direction, that is, the orthographic projections of the two are perpendicular to the third direction, that is, the projections of the two on plane A substantially overlap, and plane A is perpendicular to the third direction.

[0035] The first direction, the second direction, and the third direction intersect each other, and can be perpendicular to each other, i.e., the first direction is perpendicular to the second direction, the second direction is perpendicular to the third direction, and the first direction is perpendicular to the third direction. For example, the third direction is the thickness direction of the battery or cell 2, and one of the first direction and the second direction is the length direction of the battery or cell 2 and the other is the width direction of the battery or cell 2. That is, the first direction is the length direction of the battery or cell 2 and the second direction is the width direction of the battery or cell 2, or the first direction is the width direction of the battery or cell 2 and the second direction is the length direction of the battery or cell 2.

[0036] Specifically, the thickness T of the sealing area 10 10 The thickness can be from 210μm to 260μm, for example, 210μm, 220μm, 230μm, 240μm, 250μm, 260μm, or any combination thereof. The thickness of the sealing region 10 is equal to the distance (in the third direction) from the side of the first side 111 of the sealing region 10 away from the second side 112 to the side of the second side 112 of the sealing region away from the first side 111.

[0037] Specifically, the thickness T of the sealing area of ​​the top sealing edge 11 10 The thickness T of the sealing area 10 of the side seal 12 can be 210μm to 260μm, for example, 210μm, 220μm, 230μm, 240μm, 250μm, 260μm or any combination thereof, and the thickness T of the sealing area 10 of the side seal 12 is... 10 The thickness T of the sealing area 10 of the top sealing edge 11 can be 210μm to 260μm, for example, 210μm, 220μm, 230μm, 240μm, 250μm, 260μm or any combination thereof, and the thickness T of the sealing area 10 of the top sealing edge 11 is... 10 The thickness T of the sealing area 10 of the side sealing edge 12 10 They can be the same or different.

[0038] In addition, the width w of the sealed area 10 10 It can be greater than or equal to 2mm, that is, the width w of the sealing area 10 of the top sealing edge 11. 10 The width w of the sealing area 10 of the side sealing edge 12 can be greater than or equal to 2mm. 10 The width w of the sealing area 10 of the top sealing edge 11 can be greater than or equal to 2mm. 10 The width w of the sealing area 10 of the side sealing edge 12 10 They can be the same or different (generally they are basically the same).

[0039] Specifically, such as Figure 1As shown, the width direction of the sealing area 10 of the top sealing edge 11 is basically parallel to the first direction, and the length direction is basically parallel to the second direction; the width direction of the sealing area 10 of the side sealing edge 12 is basically parallel to the second direction, and the length direction is basically parallel to the first direction.

[0040] like Figure 1 , Figure 2 and Figure 8 As shown, in addition to the sealing area 10, the sealing edges (i.e., the top sealing edge 11 and / or the side sealing edge 12) may also have a non-sealing area 20 where the first side 111 and the second side 112 are not connected. That is, the first side 111 and the second side 112 of the non-sealing area 20 are independent of each other and are not connected, and their heat-sealing layers 101 are not fused together. The non-sealing area 20 is located on the side of the sealing area 10 away from the receiving area 110.

[0041] In some embodiments, the range of (T1+T2)-T3 is 10μm to 60μm (i.e., 10μm≤(T1+T2)-T3≤60μm). For example, (T1+T2)-T3 can be 10μm, 13μm, 15μm, 18μm, 20μm, 23μm, 25μm, 28μm, 30μm, 32μm, 35μm, 38μm, 40μm, 43μm, 45μm, 48μm, 50μm, 53μm, 55μm, 58μm, 60μm, or a range between any two of these. This is beneficial for further improving the encapsulation strength and structural stability of the sealing area 10 and increasing the battery's lifespan.

[0042] In some embodiments, T1 can be 18μm to 66μm, for example, a range of 18μm, 20μm, 25μm, 30μm, 33μm, 36μm, 38μm, 40μm, 42μm, 44μm, 47μm, 50μm, 55μm, 60μm, 66μm or any two of these.

[0043] In some embodiments, T2 can be 18μm to 66μm, for example, a range of 18μm, 20μm, 25μm, 30μm, 33μm, 36μm, 38μm, 40μm, 42μm, 44μm, 47μm, 50μm, 55μm, 60μm, 66μm or any two of these.

[0044] Specifically, T1 and T2 can be equal or unequal.

[0045] In some embodiments, T3 can be 20μm to 90μm, for example, a range of 20μm, 25μm, 30μm, 35μm, 40μm, 43μm, 45μm, 48μm, 50μm, 53μm, 55μm, 58μm, 60μm, 65μm, 70μm, 75μm, 80μm, 85μm, 90μm or any combination thereof.

[0046] Specifically, the package can be a multi-layer structure, which may include a first support layer 107, a third adhesive layer 106, a second support layer 105, a second adhesive layer 104, a metal layer 103, and the first support layer 107, the third adhesive layer 106, the second support layer 105, the second adhesive layer 104, the metal layer 103, the first adhesive layer 102, and the heat-sealing layer 101 are stacked in sequence. Using this multi-layer structure, the package can further improve the encapsulation effect, prevent moisture and other components from entering the containment area 110, and improve the battery's lifespan and other performance.

[0047] The heat-sealing layer 101 is used to encapsulate the battery cell 2, for example, by heat sealing, to close the receiving area 110. In some embodiments, the heat-sealing layer 101 may include a polypropylene layer (PP layer), i.e., its material is polypropylene (PP).

[0048] For example, the thickness of the heat-sealing layer 101 can be 36μm to 44μm, such as 36μm, 38μm, 40μm, 42μm, 44μm, or any combination thereof. It is understood that the thickness of the heat-sealing layer 101 (36μm to 44μm) here refers to the thickness of the heat-sealing layer 101 in the areas of the package that are not heat-sealed (i.e., the parts of the first side 111 and the second side 112 that are not bonded), such as the package portion corresponding to the receiving area 110 (the first main body area 1111 and the second main body area 1121), and the non-sealing area 20, which are not heat-sealed.

[0049] Furthermore, the first adhesive layer 102 may include an acid-modified polypropylene layer (APP layer), meaning its material is primarily acid-modified polypropylene (APP). Acid-modified polypropylene is a material made by acid modification of polypropylene. Through acid modification, carboxyl groups, aldehyde groups, hydroxyl groups, and other groups can be introduced into the acid-modified polypropylene, thereby improving the adhesive strength of the acid-modified polypropylene layer. In this embodiment of the invention, conventional acid-modified polypropylene materials in the art can be used to form the acid-modified polypropylene layer, and there are no particular limitations on this.

[0050] Specifically, the roughness of the side of the metal layer 103 facing the second adhesive layer 104 is greater than the roughness of the side of the metal layer 103 facing the first adhesive layer 102. The side of the metal layer 103 facing the second adhesive layer 104 is a rough surface, and the side of the metal layer 103 facing the first adhesive layer 102 is a smooth surface. When the first adhesive layer 102 is an acid-modified polypropylene layer, the adhesion between the smooth surface of the metal layer 103 and the heat-sealing layer 101 can be improved, further improving the battery's lifespan and other performance characteristics.

[0051] Specifically, the metal layer 103 may include an aluminum layer, which is generally a soft aluminum foil (ALM), such as commercially available 8021 aluminum foil, 8071 aluminum foil, etc.

[0052] For example, the above-mentioned encapsulation body is an aluminum-plastic film.

[0053] Specifically, the thickness of the metal layer 103 can be 35μm to 45μm, for example, 35μm, 36μm, 38μm, 40μm, 42μm, 44μm, 45μm or any combination thereof.

[0054] Furthermore, the aforementioned second support layer 105 may include a nylon layer, i.e., its material is oriented nylon (ONy), but is not limited thereto. The thickness of the second support layer 105 may be 13μm to 17μm, for example, 13μm, 13.5μm, 14μm, 14.5μm, 15μm, 15.5μm, 16μm, 16.5μm, 17μm, or any combination thereof.

[0055] Furthermore, the first support layer 107 may include a polyester layer, specifically a PET layer, i.e., its material is polyethylene terephthalate (PET), but is not limited thereto. The thickness of the first support layer 107 may be 10μm to 14μm, for example, 10μm, 10.5μm, 10.8μm, 11μm, 11.5μm, 12μm, 12.5μm, 13μm, 13.2μm, 13.5μm, 14μm, or any combination thereof.

[0056] In addition, the second adhesive layer 104 is used to bond the metal layer 103 and the second support layer 105, and the third adhesive layer 106 is used to bond the first support layer 107 and the second support layer 105. The third adhesive layer 106 and the second adhesive layer 104 can be conventional adhesive layers in the art, and their thicknesses can also be conventional thicknesses in the art.

[0057] For example, the ratio of the mass of the third adhesive layer 106 to the area of ​​the side of the first support layer 107 or the second support layer 105 facing the third adhesive layer 106 can be (3.3~4.8) g / m². 2 For example, 3.3g / m 2 3.5g / m 2 3.8g / m 2 4g / m 2 4.3g / m 2 4.5g / m 2 4.8g / m 2 or a range consisting of any two of them.

[0058] For example, the ratio of the mass of the second adhesive layer 104 to the area of ​​the side of the second support layer 105 (or metal layer 103) facing the second adhesive layer 104 can be (3.3~4.8) g / m². 2 For example, 3.3g / m 2 3.5g / m 2 3.8g / m 2 4g / m 2 4.3g / m 2 4.5g / m 2 4.8g / m 2 or a range consisting of any two of them.

[0059] Furthermore, the thickness T0 of the package can be greater than 90 μm, for example, within the range of 90 μm, 100 μm, 110 μm, 120 μm, 130 μm, 140 μm, 150 μm, 160 μm, 170 μm, 180 μm, 190 μm, 200 μm, or any combination thereof, but is not limited to this. This allows for better prevention of moisture penetration, further improving battery safety and lifespan.

[0060] It should be noted that, as Figure 7 and Figure 8 As shown, the thickness T0 of the package refers to the thickness of one side of the area of ​​the package that is not heat-sealed in the battery structure. That is, the thickness T0 of the package is equal to the thickness of the first main body region 1111 or the thickness of the second main body region 1121.

[0061] Specifically, the volume of cell 2 can be 240cm³. 3 ~302cm 3 For example, 240cm 3 250cm 3 260cm 3 270cm 3 280cm 3 290cm 3300cm 3 302cm 3 or a range consisting of any two of them.

[0062] In some embodiments, the length of the battery cell 2 can be 100mm to 250mm, for example, a range of 100mm, 120mm, 150mm, 180mm, 200mm, 220mm, 250mm or any two of these.

[0063] In some embodiments, the width of the battery cell 2 can be 80mm to 150mm, for example, a range of 80mm, 90mm, 100mm, 110mm, 120mm, 130mm, 140mm, 150mm or any two of these.

[0064] In some embodiments, the thickness of the battery cell 2 can be 3mm to 15mm, for example, a range of 3mm, 5mm, 8mm, 10mm, 13mm, 15mm or any combination thereof. This allows the battery cell 2 to have better heat dissipation and further improves battery safety and other performance characteristics.

[0065] Furthermore, the ratio of the thickness of cell 2 to the capacity of cell 2 can be less than 4 mm / Ah. For example, the ratio of the thickness of cell 2 to the capacity of cell 2 can be a range of 0.7 mm / Ah, 0.9 mm / Ah, 1 mm / Ah, 1.3 mm / Ah, 1.5 mm / Ah, 1.2 mm / Ah, 2.3 mm / Ah, 2.5 mm / Ah, 2.8 mm / Ah, 3 mm / Ah, 3.3 mm / Ah, 3.5 mm / Ah, 3.8 mm / Ah, or any two of these.

[0066] Specifically, cell 2 can be a cell with a capacity of less than 30Ah. The capacity of cell 2 is, for example, a range of 2Ah, 5Ah, 8Ah, 10Ah, 13Ah, 15Ah, 18Ah, 20Ah, 23Ah, 25Ah, 28Ah, 30Ah or any two of these.

[0067] The cell capacity can be measured using conventional methods in the art in the embodiments of the present invention. For example, using conventional charging and discharging cabinets and other equipment, the battery is fully charged at a rate of 1C under normal temperature conditions, and then discharged at a rate of 1C (i.e., 100% DOD (depth of discharge of 100%)), and the cell capacity is measured.

[0068] In contrast, using smaller cells makes it easier for cell 2 to absorb electrolyte, increasing the electrolyte retention (the electrolyte retention is equal to the ratio of the mass of the electrolyte injected into the containment area 110 to the capacity of cell 2), thus retaining more electrolyte and further optimizing battery performance.

[0069] Furthermore, cell 2 can be a wound cell or a laminated cell, without particular restriction. Specifically, such as Figure 6 As shown, the battery cell 2 includes a first electrode 201, a second electrode 202, and a separator 3 located between the first electrode 201 and the second electrode 202. The first electrode 201 and the second electrode 202 have opposite polarities, that is, one of the first electrode 201 and the second electrode 202 is a positive electrode and the other is a negative electrode. For example, the first electrode 201 is a positive electrode and the second electrode 202 is a negative electrode.

[0070] In addition, the battery cell 2 can be square, such as rectangular or square, but is not limited to this, and can also be other regular or irregular structures.

[0071] In specific implementation, the first electrode 201, the separator 3, and the second electrode 202 can be stacked and wound in sequence to form a wound structure to obtain a wound battery cell. Alternatively, the first electrode 201, the separator 3, and the second electrode 202 can be stacked in sequence to form a laminated battery cell.

[0072] In addition, such as Figure 1 , Figures 3 to 6 As shown, the battery cell 2 is provided with a first electrode tab connected to the first electrode plate 201. The first electrode tab extends out of the package body, specifically from the sealing edge (such as the top sealing edge 11). At the sealing edge, the first electrode tab is located between the first side 111 and the second side 112.

[0073] Specifically, such as Figure 1 , Figures 3 to 6 As shown, the first electrode ear includes a first inner electrode ear 100 and a first electrode ear portion 21 connected to the first inner electrode ear 100. The first electrode ear portion 21 extends out of the package body from the sealing area 10. Specifically, it can extend out of the package body from the sealing area 10 of the top sealing edge 11. In the sealing area 10, the first electrode ear portion 21 is located between the first side portion 111 and the second side portion 112.

[0074] Specifically, Figure 5 for Figure 1 A cross-sectional schematic diagram of region Q2 (i.e., the region with the protruding tabs) is shown in the image. Figure 5 The first electrode portion 21 includes a first internal portion 211 and a first external portion 212. The battery cell 2, the first internal electrode 100, the first internal portion 211 and the first external portion 212 are connected in sequence. The first internal portion 211 is located in the sealing area 10. The first side portion 111, the first internal portion 211 and the second side portion 112 of the sealing area 10 are stacked in sequence. The first external portion 212 is the part of the first electrode portion 21 that extends out of the package body. That is, the first external portion 212 is located outside the package body, that is, the first external portion 212 is located on the side of the sealing area 10 away from the receiving area 110.

[0075] Specifically, the first inner tab 100 and the first tab portion 21 can be welded (specifically, welded to the first internal portion 211 of the first tab portion 21) to make them electrically connected. That is, the first tab portion 21 can be a first adapter welded to the first inner tab 100, serving as a connector for connecting the battery to an electronic product using the battery. Specifically, it can be connected to the electronic product through the first external portion 212 of the first tab portion 21.

[0076] In addition, such as Figure 3 As shown, the first inner tab 100, the first tab portion 21, and the first tab formed by the two are all straight structures, basically without bending. The extension directions of the first inner tab 100, the first tab portion 21, and the first tab can be the same, specifically, they can extend along the direction from the cell 2 to the sealing area 10. In specific implementation, the first inner tab 100 and the first tab portion 21 can be directly soldered, that is, neither of them is bent.

[0077] The length direction of the first electrode ear, the length direction of the first inner electrode ear 100, the length direction of the first electrode ear portion 21, the direction along the first internal portion 211 to the first external extension portion 212, and the first direction are substantially parallel to each other.

[0078] In addition, such as Figure 1 , Figures 3 to 6 As shown, the battery cell 2 is also provided with a second electrode tab connected to the second electrode plate 202. The polarities of the first electrode tab and the second electrode tab are opposite, that is, one of them is a positive electrode tab and the other is a negative electrode tab. For example, the first electrode tab is a positive electrode tab provided on the positive electrode plate (first electrode plate 201), and the second electrode tab is a negative electrode tab provided on the negative electrode plate (second electrode plate 202).

[0079] The second electrode extends out of the package body, specifically from the sealing edge (such as the top sealing edge 11). At the sealing edge, the second electrode is located between the second side 111 and the second side 112.

[0080] Specifically, such as Figure 1 , Figures 3 to 6 As shown, the second electrode ear includes a second inner electrode ear 200 and a second electrode ear portion 22 connected to the second inner electrode ear 200. The second electrode ear portion 22 extends out of the package body from the sealing area 10. Specifically, it can extend out of the package body from the sealing area 10 of the top sealing edge 11. In the sealing area 10, the second electrode ear portion 22 is located between the second side portion 111 and the second side portion 112.

[0081] Specifically, the second tab 22 includes a second internal portion and a second external portion (not shown in the figure). The battery cell 2, the second internal tab 200, the second internal portion and the second external portion are connected in sequence. The second internal portion is located in the sealing area 10. The second side portion 111 of the sealing area 10, the second internal portion and the second side portion 112 of the sealing area 10 are stacked in sequence. The second external portion is the part of the second tab 22 that extends out of the package body, that is, the second external portion is located outside the package body, that is, the second external portion is located on the side of the sealing area 10 away from the receiving area 110.

[0082] Specifically, the second inner tab 200 and the second tab portion 22 can be welded (specifically, welded to the second internal portion of the second tab portion 22) to make them electrically connected. That is, the second tab portion 22 can be a second adapter welded to the second inner tab 200, serving as a connector for connecting the battery to an electronic product using the battery. Specifically, it can be connected to the electronic product through the second outer portion of the second tab portion 22.

[0083] In addition, such as Figure 3 As shown, the second inner tab 200, the second tab portion 22, and the second tab formed by the two are all straight structures, basically without bending. The extension directions of the second inner tab 200, the second tab portion 22, and the second tab can be the same, specifically, they can extend along the direction from the cell 2 to the sealing area 10. In specific implementation, the second inner tab 200 and the second tab portion 22 can be directly soldered, that is, neither of them is bent.

[0084] The length direction of the second electrode ear, the length direction of the second inner electrode ear 200, the length direction of the second electrode ear portion 22, the direction along the second inner portion to the second outer extension portion, and the first direction are substantially parallel to each other.

[0085] Furthermore, the thickness direction of the first electrode 21, the thickness direction of the second electrode 22, and the thickness direction of the battery or cell 2 (parallel to) Figure 2 , Figure 4 , Figure 5 , Figure 7 and Figure 8 The third direction in the middle is parallel to each other.

[0086] like Figure 1 and Figure 3 As shown, the first inner tab 100 and the second inner tab 200 can be located on the same side of the cell 2, for example, both are located on the side of the cell 2 facing the top seal edge 11, and the first tab portion 21 and the second tab portion 22 extend out of the package from the top seal edge 11.

[0087] In addition, such as Figure 3 and Figure 4As shown, a protective adhesive layer 23 is provided on the surface of the connection portion 210 between the first tab portion 21 (first internal portion 211) and the first inner tab 100. Protective adhesive layers 23 are provided on both the side of the first inner tab 100 facing away from the first tab portion 21 and the side of the first tab portion 21 facing away from the first inner tab 100. Specifically, this connection portion 210 can be the welding point between the first tab portion 21 and the first inner tab 100, and generally has solder marks (such as bumps). By providing a protective adhesive layer 23 on its surface, damage to the battery assembly, such as the battery package, can be avoided due to the solder marks, further improving the battery's safety and lifespan.

[0088] Furthermore, a protective adhesive layer 23 is also provided on the surface of the connection portion 220 between the second tab 22 (second internal portion) and the second inner tab 200. Protective adhesive layers 23 are provided on both the side of the second inner tab 200 facing away from the second tab 22 and the side of the second tab 22 facing away from the second inner tab 200 at this connection portion 220. Specifically, this connection portion 220 can be the welding point between the second tab 22 and the second inner tab 200, and generally has solder marks (such as bumps). By providing a protective adhesive layer 23 on its surface, damage to the battery assembly, such as the battery package, can be avoided due to the solder marks, further improving the battery's safety and lifespan.

[0089] The aforementioned protective adhesive layer 23 can be made of conventional adhesives in the art, such as conventional tab adhesives.

[0090] Under normal circumstances, such as Figure 6 As shown, the battery cell 2 may include a plurality of first electrode plates 201 and a plurality of second electrode plates 202. Each first electrode plate 201 is provided with a first sub-electrode tab 2011. The first sub-electrode tabs 2011 of these first electrode plates 201 are connected together to form a first inner electrode tab 100. Each second electrode plate 202 is provided with a second sub-electrode tab 2021. The second sub-electrode tabs 2021 of these second electrode plates 202 are connected together to form a second inner electrode tab 200.

[0091] The diaphragm 3 is used to separate the first electrode 201 and the second electrode 202 to prevent the first electrode 201 and the second electrode 202 from short-circuiting due to contact.

[0092] In some embodiments, such as Figure 6 As shown, the separator 3 includes at least two third side portions 31 and a bent portion 32 connecting each two adjacent third side portions 31. Each third side portion 31 is located between the first electrode 201 and the second electrode 202 to separate the first electrode 201 and the second electrode 202, thereby forming the cell 2 in a Z-shaped stacking manner.

[0093] Specifically, the diaphragm 3 can be folded to form the aforementioned third side portion 31 and bent portion 32. The third side portion 31 can be a straight portion (i.e., a flat structure), and the bent portion 32 can be a curved structure. The third side portion 31 and bent portion 32 of the diaphragm 3 are distributed along a third direction, and the first electrode 201, the third side portion 31 of the diaphragm 3, and the second electrode 202 are distributed along a third direction.

[0094] Specifically, such as Figure 6 As shown, the diaphragm 3 includes at least one repeating unit, which includes three third side portions 31 and two bent portions 32. According to the distribution order along the third direction, the first third side portion 31, the first bent portion 32, and the second third side portion 31 are connected in sequence and enclose a first region 310. The second third side portion 31, the second bent portion 32, and the third third side portion 31 are connected in sequence and enclose a second region 320. The first electrode 201 is located in the first region 310 (generally not exceeding the opening of the first region 310), and the second electrode 202 is located in the second region 320 (generally not exceeding the opening of the second region 320), so as to realize the separation of the first electrode 201 and the second electrode 202 by the third side portion 31.

[0095] When the diaphragm 3 includes multiple repeating units, the multiple repeating units are distributed along the third direction, and two adjacent repeating units share a third side 31. That is, according to the distribution order along the third direction, the third third side 31 of the previous repeating unit is the first third side 31 of the next repeating unit.

[0096] For example, such as Figure 6 As shown, the first sub-tab 2011 of the first electrode 201 located in the first region 310 extends from the first bend 32, that is, the first sub-tab 2011 passes through the bend 32. The bend 32 has a notch 30 for the first sub-tab 2011 to pass through. The second sub-tab 2021 of the second electrode 202 located in the second region 320 extends from the opening of the second region 320, so that the first sub-tab 2011 and the second sub-tab 2021 are located on the same side of the cell 2.

[0097] The positive electrode tab can be made of aluminum (i.e., the positive electrode tab is an aluminum electrode tab), and the negative electrode tab can be made of copper-plated nickel material (i.e., the negative electrode tab is a copper-plated nickel electrode tab), but is not limited to these.

[0098] In addition, the aforementioned batteries may include, but are not limited to, lithium-ion batteries.

[0099] Specifically, the aforementioned positive electrode sheet includes a positive current collector and a positive active layer disposed on at least one surface of the positive current collector. The positive active layer includes a positive active material, a first conductive agent, and a first binder. The mass percentage content of the positive active material can be 90% to 98%, for example, 90%, 91%, 92%, 93%, 94%, 95%, 96%, 97%, 98%, or any two of these. The mass percentage content of the first conductive agent can be 1% to 5%, for example, 1%, 2%, 3%, 4%, 5%, or any two of these. The mass percentage content of the first binder can be 1% to 5%, for example, 1%, 2%, 3%, 4%, 5%, or any two of these.

[0100] The positive electrode current collector may have a positive electrode active layer on one surface, or both surfaces of the positive electrode current collector may have a positive electrode active layer. The positive electrode current collector may include aluminum foil, and the positive electrode active material may include one or more of lithium iron phosphate (LFP), lithium cobalt oxide, lithium manganese oxide, lithium nickel oxide, lithium nickel cobalt manganese oxide, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium oxide phosphate, lithium-rich manganese-based materials, and lithium nickel cobalt aluminum oxide.

[0101] Furthermore, the aforementioned negative electrode sheet includes a negative electrode current collector and a negative electrode active layer disposed on at least one surface of the negative electrode current collector. The negative electrode active layer includes a negative electrode active material, a second conductive agent, and a second binder. The mass percentage content of the negative electrode active material can be 86% to 98%, for example, 86%, 88%, 90%, 93%, 95%, 98%, or any two of these. The mass percentage content of the second conductive agent can be 1% to 7%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, or any two of these. The mass percentage content of the second binder can be 1% to 7%, for example, 1%, 2%, 3%, 4%, 5%, 6%, 7%, or any two of these.

[0102] The negative electrode current collector may have a negative electrode active layer on one surface, or both its negative and positive surfaces may have a negative electrode active layer. The negative electrode current collector may include copper foil, and the negative electrode active material may include one or more of graphite, mesophase carbon microspheres, soft carbon, hard carbon, silicon materials, silicon-oxygen materials, and silicon-carbon materials. Specifically, the graphite may include artificial graphite and / or natural graphite.

[0103] In addition, the negative electrode active layer may also include a thickener, such as sodium carboxymethyl cellulose.

[0104] For example, the first conductive agent and the second conductive agent may each include one or more of conductive carbon black, acetylene black, carbon nanotubes, conductive graphite, graphene, etc., and the first binder and the second binder may each include one or more of polyvinylidene fluoride (PVDF), a copolymer of polyvinylidene fluoride and hexafluoropropylene, polyamide, polyacrylonitrile, polyacrylate, polyacrylic acid, polyacrylate, polyvinylpyrrolidone, polyvinyl ether, polymethyl methacrylate, polytetrafluoroethylene, polyhexafluoropropylene, and styrene-butadiene rubber (SBR).

[0105] In addition, the battery also includes an electrolyte, which may include an organic solvent and a lithium salt. The organic solvent may include one or more of ethylene carbonate, dimethyl carbonate, and 1,2-propylene glycol carbonate. The lithium salt may include lithium hexafluorophosphate. The concentration of the lithium salt in the electrolyte may be, for example, 1 mol / L to 1.5 mol / L, such as 1 mol / L, 1.2 mol / L, 1.3 mol / L, 1.4 mol / L, 1.5 mol / L, or any combination thereof, but is not limited thereto.

[0106] The electrode sheets and battery of the present invention can be manufactured by conventional methods in the art, such as by coating to produce positive and negative electrode sheets, that is, by mixing the corresponding active materials, conductive agents, binders and other materials with solvents to form a slurry, and then coating the slurry onto a current collector, and then obtaining the corresponding electrode sheets through processes such as drying and rolling. Then, the bare cell 2 can be formed by the above-mentioned Z-shaped stacking method, or by winding to form a wound bare cell 2, and then welding adapters (the first adapter (first tab 21) is welded to the positive tab (first inner tab 100) of the positive electrode sheet, and the second adapter (second tab 22) is welded to the negative tab (second inner tab 200) of the negative electrode sheet) to turn out the positive and negative tabs, the cell 2 is encapsulated by a package, and electrolyte is injected into the accommodating area 110, and then the battery is obtained through processes such as formation and aging.

[0107] The present application will be further described below through specific embodiments.

[0108] (1) Preparation of positive electrode

[0109] Lithium iron phosphate, PVDF, and conductive carbon black are mixed and dispersed evenly by high-speed stirring to obtain a first mixture. In the first mixture, the mass percentage of lithium iron phosphate is 91 wt%, the mass percentage of PVDF is 4 wt%, and the mass percentage of conductive carbon black is 5 wt%.

[0110] The first mixture was mixed with N-methylpyrrolidone (NMP) to prepare a positive electrode slurry with a solid content of 50 wt%.

[0111] The positive electrode slurry is evenly coated on both sides of the aluminum foil, and after drying and compaction by a roller press, a positive electrode sheet is obtained.

[0112] (2) Preparation of negative electrode

[0113] Artificial graphite, PVDF, aziridine (crosslinking agent), sodium carboxymethyl cellulose and conductive carbon black are mixed and dispersed evenly by high-speed stirring to obtain a second mixture; in the second mixture, the mass percentage of artificial graphite is 95 wt%, the mass percentage of sodium carboxymethyl cellulose is 1.5 wt%, the mass percentage of conductive carbon black is 1.5 wt%, and the mass percentage of PVDF is 2 wt%.

[0114] The second mixture is mixed with water to prepare a negative electrode slurry with a solid content of 50 wt%.

[0115] The negative electrode slurry is evenly coated on both sides of the copper foil, and after drying and compaction by a roller press, the negative electrode sheet is obtained.

[0116] (3) Battery assembly

[0117] Battery structure such as Figures 1 to 9 As shown, its preparation process is as follows:

[0118] The positive electrode, separator 3, and negative electrode are stacked in a Z-shape to form a bare cell 2 (or wound to form a bare cell 2);

[0119] The aluminum tabs (first sub-tabs 2011) of the positive electrode plates (multiple) in the battery cell 2 are welded together to form the first inner tab 100. The copper-plated nickel tabs (second sub-tabs 2021) of the negative electrode plates (multiple) in the battery cell 2 are welded together to form the second inner tab 200. The first inner tab 100 is welded to the first tab portion 21 to form the first tab. The second inner tab 200 is welded to the second tab portion 22 to form the second tab, thereby turning out the positive tab and the negative tab respectively.

[0120] Clamp the bare battery cell 2 with a glass clamp, the clamp force being 100MPa / m. 2 The battery is then baked at 85°C under vacuum for 24 hours, and then encapsulated with an aluminum-plastic film with a thickness of 153μm. An electrolyte is injected into the housing area 110 of the battery cell 2. The electrolyte consists of an organic solvent and lithium hexafluorophosphate. The organic solvent is a mixture of ethylene carbonate, dimethyl carbonate, and 1,2-propylene glycol carbonate in a volume ratio of 1:1:1. The concentration of lithium hexafluorophosphate in the electrolyte is 1.1 mol / L.

[0121] The battery cell has a capacity of approximately 5Ah, a length of approximately 130mm, a width of approximately 110mm, and a thickness of approximately 4.5mm.

[0122] The aluminum-plastic film includes a PET layer with a thickness of approximately 12 μm, and a third adhesive layer 106, which are stacked sequentially from the outside to the inside. The ratio of the mass of the third adhesive layer 106 to the area of ​​the side of the PET layer (or nylon layer) facing the third adhesive layer 106 is approximately 3.3 g / m². 2 A nylon layer with a thickness of approximately 15 μm, and a second adhesive layer 104 (the ratio of the mass of the second adhesive layer 104 to the area of ​​the side of the nylon layer (or aluminum layer) facing the second adhesive layer 104 is approximately 3.3 g / m²). 2 The soft aluminum layer with a thickness of approximately 38.48 μm, the APP layer (PPa) with a thickness of approximately 40 μm, and the PP layer (heat-sealing layer 101) with a thickness of approximately 40 μm are respectively. The side of the soft aluminum layer facing the second adhesive layer 104 (which is also the side facing the nylon layer) is a rough surface, and the side of the soft aluminum layer facing the APP layer (which is also the side facing the PP layer) is a smooth surface.

[0123] Specifically, Figure 9 The scanning electron microscope (SEM) images of the aluminum-plastic film used show that the distance from the side of the PET layer away from the nylon layer to the side of the nylon layer away from the PET layer is approximately 35.4 μm (the distances measured in two different areas are 35.52 μm and 35.30 μm, respectively). The distance from the side of the APP layer facing the soft aluminum layer to the side of the PP layer away from the APP layer is approximately 80.96 μm. The distance from the side of the PET layer away from the nylon layer to the side of the PP layer away from the APP layer (encapsulation thickness) is approximately 152.62 μm.

[0124] The enclosure 110 is sealed by heat sealing. The heat sealing layer 101 of the first side 111 and the heat sealing layer 101 of the second side 112 of the sealing area 10 are combined into one unit (i.e., forming a connecting layer 108, such as...). Figure 2 (as shown); wherein, the thickness T3 of the connecting layer 108 is approximately 50 μm, the thickness T1 of the APP layer (first adhesive layer 102) on the first side is approximately 40 μm, the thickness T2 of the APP layer (first adhesive layer 102) on the second side is approximately 40 μm, the thickness of the sealing area 10 is approximately 235 μm, the width of the sealing area 10 (effective sealing area) of the top sealing edge 11 is 2 mm, and the width of the sealing area 10 of the side sealing edge 12 is 2 mm;

[0125] Then, through formation and aging processes, a square soft-pack battery is produced. The battery has a length of 140mm, a width of 145mm, and a thickness of 14mm.

[0126] The results of the high-temperature and high-humidity accelerated testing show that the battery can meet the service life requirement of more than 12 years, meaning that even after more than 8 years of use, it can still maintain a high capacity retention rate and other performance characteristics. The high-temperature and high-humidity accelerated testing process is as follows: at room temperature, the battery cell is charged to full charge (100% SOC) and then placed in a high-temperature (65℃) and high-humidity (95% relative humidity) chamber for accelerated testing. The encapsulation life of the battery cell under room temperature conditions (equivalent factor AF = 40.83) is calculated based on the high-temperature storage time. For example, storing the battery at 60℃ and 95% relative humidity (RH) for 107.3 days is equivalent to storing it at room temperature for 107.3 × 40.83 ÷ 365 = 12 years.

[0127] The simulation results show that after 12 years of storage and use at room temperature, the capacity loss due to storage is 10.5%, the capacity loss due to cycling is about 6.4%, and the overall capacity retention rate is about 83.1%.

[0128] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and not to limit them; although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of the present invention.

Claims

1. A battery, characterized by, The device includes a battery cell and a package for encapsulating the battery cell. The package includes a housing area and a sealing area that closes the housing area. The battery cell is located within the housing area. The package includes a first adhesive layer and a heat-sealing layer connected together. The package has a first side and a second side. The heat-sealing layer on the first side of the sealing area is connected to the heat-sealing layer on the second side of the sealing area. The thickness of the first adhesive layer on the first side of the sealing area is T1, and the thickness of the first adhesive layer on the second side of the sealing area is T2. In the sealing area, the sum of the thicknesses of the heat-sealing layers on the first side and the second side is T3, where T3 < T1 + T2.

2. The battery according to claim 1, characterized in that, 10μm≤(T1+T2)-T3≤60μm; and / or, The T1 is 18μm to 66μm; and / or, The T2 is 18μm to 66μm; and / or, The T3 is 20μm to 90μm.

3. The battery according to claim 1, characterized in that, The first adhesive layer on the first side of the sealing area and the first adhesive layer on the second side of the sealing area are combined into one unit.

4. The battery according to claim 1, characterized in that, The first adhesive layer includes an acid-modified polypropylene layer; and / or, The heat-sealing layer includes a polypropylene layer.

5. The battery according to any one of claims 1-4, characterized in that, The package further includes a first support layer, a third adhesive layer, a second support layer, a second adhesive layer, and a metal layer, wherein the first support layer, the third adhesive layer, the second support layer, the second adhesive layer, the metal layer, the first adhesive layer, and the heat-sealing layer are stacked.

6. The battery according to claim 5, characterized in that, The first support layer includes a polyester layer; and / or, The second support layer includes a nylon layer; and / or, The metal layer includes an aluminum layer; and / or, The surface roughness of the metal surface facing the second adhesive layer is greater than the surface roughness of the metal surface facing the first adhesive layer.

7. The battery according to any one of claims 1-4, characterized in that, The thickness of the package is greater than 90 μm.

8. The battery according to any one of claims 1-4, characterized in that, The thickness of the sealing area is 210μm to 260μm; and / or, The width of the sealing area is greater than or equal to 2 mm.

9. The battery according to claim 1, characterized in that, The battery cell has a capacity of less than 30Ah; And / or, the ratio of the cell thickness to the cell capacity is less than 4 mm / Ah.

10. The battery according to claim 1 or 9, characterized in that, The volume of the cell is 240 cm 3 ~ 302 cm 3 ; And / or, the length of the battery cell is 100mm to 250mm, and / or, the width of the battery cell is 80mm to 150mm, and / or, the thickness of the battery cell is 3mm to 15mm.

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