Battery and battery module

Abstract

The application provides a battery and a battery module. The battery module comprises a plurality of batteries connected in sequence, each battery comprising a battery cell and an annular protective film. The first end of the battery cell is provided with a tab assembly. The annular protective film is arranged around the circumferential surface of the battery cell. The inner walls of the first end of the annular protective film are close to each other and connected to form a first sealing edge for sealing the battery cell. The inner walls of the second end of the annular protective film opposite to the first end are close to each other and connected to form a second sealing edge for sealing the battery cell. The tab assembly extends from the first sealing edge of the annular protective film to the outside of the annular protective film. The second sealing edge has a folded edge folded towards the direction close to the battery cell. The battery and the battery module solve the technical problem of low energy density of the battery in the related art.

Description

Technical Field

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

[0002] Batteries typically include steel-cased batteries and pouch batteries. Steel-cased batteries have the battery cells encapsulated in a metal casing, while pouch batteries have the battery cells encapsulated in an aluminum-plastic film. Because the aluminum-plastic film is thinner, pouch batteries are lighter and have a higher energy density than steel-cased batteries.

[0003] However, due to the aluminum-plastic film encapsulation method, pouch batteries in related technologies have a lower energy density. Utility Model Content

[0004] The embodiments of this application provide a battery and a battery module that can improve the technical problem of low energy density in batteries.

[0005] In a first aspect, this application provides a battery comprising:

[0006] The battery cell has a tab assembly at its first end;

[0007] An annular protective film is provided around the periphery of the battery cell. The inner walls of the first end of the annular protective film are close to each other and connected to form a first sealing edge for sealing the battery cell. The inner walls of the second end of the annular protective film opposite to the first end are close to each other and connected to form a second sealing edge for sealing the battery cell.

[0008] The tab assembly extends from the sealing edge of the first end of the annular protective film to the outside of the annular protective film, and the second sealing edge has a folded edge that folds towards the direction of the battery cell. This design reduces the number of folded edges on the battery, thereby increasing the capacity of the battery cell to some extent.

[0009] In some embodiments, along the height direction of the battery, the maximum height L of the annular protective film and the maximum height A of the folded edge satisfy the following relationship: 0.005 ≤ A / L ≤ 0.5; and / or,

[0010] Along the height direction of the battery, the maximum height A of the folded edge satisfies the relationship 0.8mm ≤ A ≤ 4mm; and / or,

[0011] The maximum thickness H1 of the annular protective film is greater than the maximum thickness H2 of the folded edge. This design ensures that the volume occupied by the folded edge is not too large, and that the folded edge design also enables the annular protective film to have a good protective effect.

[0012] In some embodiments, the folded edge abuts against the outer peripheral surface of the annular protective film; and / or,

[0013] An adhesive layer is provided between the folded edge and the annular protective film. This design prevents the folded edge from springing back or lifting, which could affect other components in the battery.

[0014] In some embodiments, the maximum width W of the annular protective film along the width direction of the battery and the maximum height L of the annular protective film along the height direction of the battery satisfy the relationship: L > W / 2. This configuration ensures that the energy density of the battery using the annular protective film is higher than that of the battery using the square aluminum-plastic film.

[0015] In some embodiments, the annular protective film includes at least an insulating fusion bonding layer, which are close to each other and connected to form a first sealing edge and a second sealing edge for sealing the battery cell. This arrangement facilitates the sealing of the battery cell by the annular protective film and improves the insulation performance of the battery cell.

[0016] In some embodiments, the annular protective film further comprises a barrier layer and a protective layer, wherein the barrier layer is bonded to the outer surface of the insulating fusion bonding layer, and the protective layer is bonded to the outer surface of the barrier layer. This configuration improves the battery's wear resistance, structural strength, and insulation effect.

[0017] In some embodiments, the annular protective film comprises a circular annular protective film; and / or,

[0018] The insulating fusion bonding layer comprises at least one selected from a polypropylene layer, a polyethylene terephthalate layer, a polyethylene layer, and an ethylene acrylate layer; and / or,

[0019] The barrier layer includes at least one of an aluminum layer, an aluminum alloy layer, and a copper alloy layer; and / or,

[0020] The protective layer includes at least one of a polyamide layer and a polyethylene terephthalate layer.

[0021] In some embodiments, an insulating adhesive layer is provided on the outer periphery of the tab assembly, and the insulating fusion adhesive layer is bonded to the insulating adhesive layer. This configuration improves the connection between the tab assembly and the annular protective film and prevents the tab assembly from directly contacting the conductive barrier layer.

[0022] In some embodiments, the annular protective film is integrally formed. This arrangement eliminates any joints on the annular protective film, preventing excessive stress at the joints that could damage the film.

[0023] The annular protective film includes a square main body, with a first adhesive portion and a second adhesive portion respectively provided at opposite ends of the square main body. The square main body is bonded together by the first adhesive portion and the second adhesive portion. This design can reduce the manufacturing cost of the annular protective film to a certain extent.

[0024] Secondly, this application also provides a battery module, which includes the battery mentioned above.

[0025] Unlike related technologies, this application uses an annular protective film, and after the battery is packaged, the two sides of the annular protective film do not need to be heat-fused to form a seal. In contrast, related technologies have seals on both sides of the cell, meaning that the battery in related technologies has a total of three seals. In this application, the battery only has two seals, which reduces the volume occupied by the seals and allows the cell size to be made larger, thereby improving the energy density of the battery. Attached Figure Description

[0026] 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 accompanying 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.

[0027] Figure 1 This is a perspective structural diagram of a battery in the prior art;

[0028] Figure 2 This is a schematic diagram of the structure of the battery module provided in an embodiment of this application;

[0029] Figure 3 This is a perspective structural diagram of the battery provided in an embodiment of this application;

[0030] Figure 4 This is a cross-sectional schematic diagram of a battery provided in an embodiment of this application;

[0031] Figure 5 This is a cross-sectional schematic diagram of the annular protective film provided in an embodiment of this application;

[0032] Figure 6 This is a schematic diagram of the structure of an annular protective film provided in an embodiment of this application;

[0033] Figure 7 This is a schematic diagram of another annular protective film provided in an embodiment of this application.

[0034] The above figures include the following reference numerals:

[0035] 1. Battery module; 10. Battery; 11. Battery cell; 12. Annular protective film; 13. Tab assembly; 14. Square aluminum-plastic film; 120. Through hole; 121. Edge sealing; 122. Folded edge; 123. Insulating adhesive layer; 124. Barrier layer; 125. Protective layer; 126. Adhesive layer; 127. First adhesive part; 128. Second adhesive part; 129. Square body; 131. Insulating adhesive layer; 1211. First edge sealing; 1212. Second edge sealing. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of the embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. In addition, it should be understood that the specific embodiments described herein are only for illustration and explanation of this application and are not intended to limit this application. In this application, unless otherwise stated, directional terms such as "upper" and "lower" generally refer to the upper and lower positions of the device in actual use or operation, specifically the drawing directions in the accompanying drawings; while "inner" and "outer" refer to the outline of the device.

[0037] See Figure 1 As shown, in the related technology, the packaging method of the soft-pack battery adopts the following process: First, the square aluminum-plastic film 14 is stamped to form an installation space for mounting the battery cell 11. Then, the battery cell 11 is placed inside the square aluminum-plastic film 14, and the square aluminum-plastic film 14 is folded in half. Subsequently, the square aluminum-plastic film 14 is heat-fused to form a sealing edge 121 on one side of the battery cell 11 and the top with the tab assembly 13. After the battery is sealed, electrolyte is injected into the battery cell 11 through the unsealed side of the aluminum-plastic film. Then, this side is sealed, and the excess square aluminum-plastic film 14 is trimmed off.

[0038] To address the problems existing in the relevant technologies, please refer to the appendix. Figure 2 and Figure 3As shown, this application provides a battery module 1, which includes a plurality of batteries 10 connected in sequence. Each battery 10 includes a cell 11 and an annular protective film 12. A tab assembly 13 is provided at the first end of the cell 11. The annular protective film 12 surrounds the peripheral side of the cell 11. The inner walls of the first end of the annular protective film 12 are close to each other and connected to form a first sealing edge 1211 for sealing the cell 11. The inner walls of the second end of the annular protective film 12 opposite to the first end are close to each other and connected to form a second sealing edge 1212 for sealing the cell 11. It is worth mentioning that the annular protective film 12 surrounding the peripheral side of the cell 11 means that the annular protective film 12 has a through hole 120, and the cell 11 is installed in the through hole 120, so that the annular protective film 12 surrounds the peripheral side of the cell 11. The peripheral side of the cell 11 refers to the surface other than the side of the cell 11 with the tab assembly 13 and the other side opposite to the tab assembly 13.

[0039] Specifically, since the battery 10 of this application uses an annular protective film 12, when packaging the battery 10 pack, the battery cell 11 is first installed inside the annular protective film 12. Then, a first sealing edge 1211 with the tab assembly 13 protruding from the annular protective film 12 is sealed. Next, electrolyte is injected into the battery cell 11 through the second end of the annular protective film 12. Finally, the unsealed second end of the annular protective film 12 is sealed to form a second sealing edge 1212. In this embodiment, the tab assembly 13 includes a positive tab and a negative tab, and both the positive and negative tabs protrude from the first end of the annular protective film 12.

[0040] Unlike related technologies, this application uses an annular protective film 12, and after the battery 10 is packaged, the two sides of the annular protective film 12 do not need to be heat-fused to form sealing edges 121. In contrast, related technologies have sealing edges on both sides of the battery cell, meaning that in related technologies, a total of three sealing edges are generated on the battery. In this application, the battery only has two sealing edges 121, thereby reducing the volume occupied by the sealing edges 121. This allows the battery cell 11 to be made larger, thereby improving the energy density of the battery.

[0041] Furthermore, in order to improve the stability of the pouch battery, the aluminum-plastic film on both sides of the cell 11 needs to be folded to prevent electrolyte leakage from the sealing edges 121 on both sides of the cell 11 after heat sealing failure. However, this packaging process causes a problem: when the volume of the pouch battery is fixed, the folded edges on both sides of the cell 11 result in a larger volume occupied by the aluminum-plastic film, which in turn reduces the volume of the cell 11, ultimately leading to a lower energy density of the pouch battery.

[0042] It is worth mentioning that the reason why the folded edge 122 causes the volume of the cell 11 to decrease accordingly is that when the thickness of the battery 10 is fixed, the folded edge 122 needs to be folded, which will increase the thickness of the annular protective film 12 at the folded edge 122. Therefore, the thickness of the cell 11 at this point needs to be reduced accordingly, thereby reducing the overall volume of the battery 10 occupied by the cell 11.

[0043] In some embodiments, the second sealing edge 1212 has a folded edge 122 folded towards the direction of the battery cell 11. Specifically, in this embodiment, after sealing the second end of the annular protective film 12, the second end of the annular protective film 12 is folded towards the direction of the battery cell 11 to form the folded edge 122. Furthermore, the first end of the annular protective film 12 does not need to have a folded edge 122 because the tab assembly 13 needs to pass through the first end of the annular protective film 12 and connect to other external components. In related technologies, there are two folded edges 122 on both sides of the battery cell; however, this application reduces the number of folded edges 122 on the battery 10 through the design of the annular protective film 12, thereby reducing the overall volume occupied by the annular protective film 12 on the battery 10, and correspondingly allowing the battery cell 11 to be made larger, thereby improving the energy density of the battery 10.

[0044] In some embodiments, along the height direction of the battery 10, the maximum height L of the annular protective film 12 and the maximum height A of the folded edge 122 satisfy the following relationship: 0.005≤A / L≤0.5.

[0045] Specifically, when A / L is less than 0.005, the maximum height A of the folded edge 122 is smaller than the maximum height L of the annular protective film 12. This may result in weaker protection of the second end of the annular protective film 12 by the folded edge 122. When the second sealing edge 1212 of the annular protective film 12 fails, the electrolyte inside the battery 10 may leak through the folded edge 122. When A / L is greater than 0.5, the maximum height A of the folded edge 122 is larger than the maximum height L of the annular protective film 12. A larger folded edge 122 will occupy too much space, resulting in a relatively smaller volume of the cell 11 and ultimately a decrease in the energy density of the battery 10. When A / L satisfies the above relationship, the height of the folded edge 122 will not be too high or too low compared to the height of the annular protective film 12. In this case, the battery 10 can have a higher energy density, and the protection of the second end of the annular protective film 12 is better. In this embodiment, the value of A / L can be 0.005, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, and 0.5, etc.

[0046] In some embodiments, along the height direction of the battery 10, the maximum height A of the folded edge 122 satisfies the relationship 0.8mm ≤ A ≤ 4mm. When A satisfies the above relationship, the maximum height of the folded edge 122 will not be too high, and the energy density of the battery 10 will be relatively high; at the same time, the maximum height of the folded edge 122 will not be too low, and the protective effect of the second end of the annular protective film 12 will be better. In this embodiment, the value of A can be 0.8mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, and 4mm, etc.

[0047] In some embodiments, as shown in the appendix Figure 4 As shown, the maximum thickness H1 of the annular protective film 12 is greater than the maximum thickness H2 of the folded edge 122. It is understandable that if the maximum thickness H1 of the annular protective film 12 is less than the maximum thickness H2 of the folded edge 122, this could result in the battery 10 having an excessively large maximum thickness, ultimately preventing the battery 10 from being installed within the installation space reserved for it in the electrical device. Therefore, in this embodiment, to solve this problem, the maximum thickness H1 of the annular protective film 1210 needs to be greater than the maximum thickness H2 of the folded edge 122.

[0048] In some embodiments, the folded edge 122 is attached to the outer peripheral surface of the annular protective film 12. Specifically, when actually encapsulating the battery 10, after the folded edge 122 is folded, it may return to its original shape. Therefore, after the folded edge 122 is folded, a hot pressing process is used to shape the folded edge 122 so that it is attached to the outer peripheral surface of the annular protective film 12, thus preventing the folded edge 122 from springing back.

[0049] Similarly, to prevent the folded edge 122 from warping or springing back, in some embodiments, an adhesive layer (not shown) is provided between the folded edge 122 and the annular protective film 12, i.e., they can be bonded by applying adhesive between the folded edge 122 and the annular protective film 12. Of course, in some embodiments, the folded edge 122 can be shaped by a hot pressing process first, and then adhesive can be applied between the outer peripheral surface of the folded edge 122 and the annular protective film 12 to form an adhesive layer between the folded edge 122 and the annular protective film 12, thereby improving the stability of the folded edge 122.

[0050] In some embodiments, the maximum width W of the annular protective film 12 along the width direction of the battery 10 and the maximum height L of the annular protective film 12 along the height direction of the battery 10 satisfy the relationship: L > W / 2.

[0051] In fact, the energy density loss of battery 10 is related to the area of ​​the folded edge 122, assuming that there is no cell 11 inside the protective film at the folded edge 122. When the protective film is the square aluminum-plastic film 14 disclosed in related technologies, the energy density loss C1 of cell 11 can be calculated using the area of ​​the folded edge 122: C1 = 2s * n * L, where L represents the highest height along the height direction of the square aluminum-plastic film 14, s represents the folding width of the folded edge 122, and n represents the number of active material layers in cell 11. Using the annular protective film 12 in this embodiment, the energy density loss C2 of cell 11 can be obtained using the area of ​​the folded edge 122: C2 = s * n * W, where W is the maximum width of the annular protective film 12 along the width direction of battery 10. If C1 = C2, we can obtain W = 2L, that is, the energy density loss of the soft-pack battery using the square aluminum-plastic film 14 is the same as that of the soft-pack battery using the annular protective film 12. If C1 < C2, then W > 2L. Clearly, the energy density loss of the pouch cell using the annular protective film 12 is higher than that of the pouch cell using the square aluminum-plastic film 14 in related technologies. However, when C1 > C2, then L > W / 2, and the energy density of the pouch cell using the annular protective film 12 is higher than that of the pouch cell using the square aluminum-plastic film 14.

[0052] In some embodiments, the annular protective film 12 includes at least an insulating fusion adhesive layer 123. The insulating fusion adhesive layers 123 are close to each other and connected to form a first sealing edge 1211 and a second sealing edge 1212 for sealing the battery cell 11. Specifically, the design of the insulating fusion adhesive layer 123 eliminates the need for adhesive bonding between the outer peripheral surface of the battery cell 11 and the inner wall surface of the annular protective film 12. When the battery cell 11 needs to be encapsulated, the annular protective film 12 can be heated to melt the insulating fusion adhesive layers 123 and bond them together, thereby forming the sealing edge 121 for sealing the battery cell 11. In addition, the insulating fusion adhesive layer 123 can also improve the insulation effect of the battery cell 11, preventing the battery cell 11 from contacting other electrical components in the battery 10 and causing a short circuit in the battery cell 11. In some embodiments, the insulating fusion adhesive layer 123 includes at least one of a polypropylene layer, a polyethylene terephthalate layer, a polyethylene layer, and an ethylene acrylate layer. Preferably, the insulating fusion bonding layer 123 is made of polypropylene, which has low manufacturing cost and good insulation and bonding properties.

[0053] See appendix Figure 5As shown, in some embodiments, the annular protective film 12 is further provided with a barrier layer 124 and a protective layer 125. The barrier layer 124 is bonded to the outer surface of the insulating fusion bonding layer 123, and the protective layer 125 is bonded to the outer surface of the barrier layer 124. In this embodiment, the barrier layer 124 is used to prevent water vapor or oxygen from entering the battery cell 11, thus preventing corrosion or expansion of the battery cell 11. In some embodiments, the barrier layer 124 includes at least one of an aluminum layer, an aluminum alloy layer, and a copper alloy layer. Using an aluminum layer results in low manufacturing costs, and the aluminum layer, after oxidation, can form a dense oxide layer on the surface of the aluminum, further improving the barrier effect of the annular protective film 12. The aluminum alloy layer has a higher barrier effect and a relatively low manufacturing cost. Using a copper alloy layer can improve the heat dissipation effect of the annular protective film 12, preventing the annular protective film 12 from overheating and causing the insulating fusion bonding layer 123 to melt. The protective layer 125 is used to improve the corrosion resistance, scratch resistance, and wear resistance of the annular protective film 12. In some embodiments, the protective layer 125 includes at least one of a polyamide layer and a polyethylene terephthalate layer. The polyamide layer has high strength and abrasion resistance and low manufacturing cost, while the polyethylene terephthalate layer has good corrosion resistance. In some embodiments, an adhesive layer 126 is provided between the insulating fusion bonding layer 123 and the barrier layer 124, and between the barrier layer 124 and the protective layer 125.

[0054] In some embodiments, the annular protective film 12 includes a circular annular protective film 12. Specifically, using an arc-shaped protective film can avoid the problem of having sharp edges on, for example, a square annular protective film 12. The presence of sharp edges may cause excessive stress at the edges after the battery 10 is encapsulated, resulting in cracking of the annular protective film 12.

[0055] Since the tab assembly 13 needs to extend through the annular protective film 12, and since a folded edge 122 cannot be provided at the point where the tab assembly 13 extends through the annular protective film 12, an insulating adhesive layer 131 is provided on the outer periphery of the tab assembly 13 in some embodiments to improve the connection stability between the annular protective film 12 and the tab assembly 13. An insulating fusion adhesive layer 123 is bonded to the insulating adhesive layer 131. Specifically, the bonding between the insulating fusion adhesive layer 123 and the insulating adhesive layer 131 can improve the connection stability of the tab assembly 13. On the other hand, since the insulating adhesive layer 131 is provided on the outer periphery of the tab assembly 13, direct contact between the tab assembly 13 and the conductive barrier layer 124 can be avoided. In some embodiments, the insulating adhesive layer can be a polypropylene layer.

[0056] In some embodiments, as shown in the appendix Figure 6 As shown, the annular protective film 12 is integrally formed. Specifically, the annular protective film 12 can be manufactured by blow molding. The integral forming of the annular protective film 12 can avoid the presence of connection gaps on the annular protective film 12, thereby improving the tear resistance of the annular protective film 12.

[0057] In other embodiments, as shown in the appendix Figure 7 As shown, the annular protective film 12 includes a square body 129. The two opposite ends of the square body 129 are respectively provided with a first adhesive portion 127 and a second adhesive portion 128. The square body 129 is bonded together by the first adhesive portion 127 and the second adhesive portion 128.

[0058] Specifically, the square body 129 includes a rectangular body or a square body. After the rectangular body or square body is rolled up, it is bonded to the second adhesive portion 128 through the first adhesive portion 127, thereby forming an annular protective film 12. In some embodiments, both the first adhesive portion 127 and the second adhesive portion 128 can be an insulating fusion bonding layer 123, and the first adhesive portion 127 and the second adhesive portion 128 can also be an adhesive layer 126. Unlike the method of integrally molding the annular protective film 12, this method of manufacturing the annular protective film 12 can reduce the manufacturing cost of the annular protective film 12 to a certain extent.

[0059] On the other hand, this application also provides some specific embodiments to illustrate the difference in energy density between the battery 10 in the related art and the battery 10 in this application:

[0060] Example 1:

[0061] The protective film is a circular protective film 12, which has a height of 40mm, a width of 90mm, and a thickness of 5.2mm. At this time, the energy density of the battery 10 is 644Wh / L.

[0062] Comparative Example 1:

[0063] Unlike Example 1, the protective film is a square aluminum-plastic film 14, and the energy density of the battery 10 is 652 Wh / L. A comparison between Example 1 and Comparative Example 1 shows that L < W / 2 for the protective film, therefore the energy density of the battery 10 using the annular protective film 12 is lower than that of the battery 10 using the square aluminum-plastic film 14.

[0064] Example 2:

[0065] Unlike Example 1, the annular protective film 12 has a height of 80 mm, a width of 40 mm, and a thickness of 6.8 mm, and the energy density of the battery 10 is 663 Wh / L.

[0066] Comparative Example 2:

[0067] Unlike Example 2, the protective film is a square aluminum-plastic film 14, and the energy density of the battery 10 is 663Wh / L. Since L = W / 2 for the protective film, the energy densities of the two types of batteries 10 are the same.

[0068] Example 3:

[0069] Unlike Example 1, the annular protective film 12 has a height of 80 mm, a width of 40 mm, and a thickness of 4.6 mm, and the energy density of the battery 10 is 720 Wh / L.

[0070] Comparative Example 3:

[0071] Unlike Example 3, the protective film is a square aluminum-plastic film 14, and the energy density of the battery 10 is 710Wh / L. Since L > W / 2, the energy density of the battery 10 using the annular protective film 12 is higher than that of the battery 10 using the square aluminum-plastic film 14.

[0072] In summary, the battery 10 of this application employs an annular protective film 12, with a folded edge 122 only at the second end of the annular protective film 12. This ensures good protection performance for the battery 10 while improving its energy density to a certain extent. Furthermore, this application further improves the energy density of the battery 10 by limiting the size of the first folded edge 122 and the maximum width and height of the annular protective film 12. In addition, the annular protective film 12 further enhances the protection performance of the battery 10 through the design of the insulating fusion bonding layer 123, the barrier layer 124, and the protective layer 125.

[0073] The embodiments of this application have been described in detail above. Specific examples have been used to illustrate the principles and implementation methods of this application. The description of the above embodiments is only for the purpose of helping to understand the method and core ideas of this application. At the same time, for those skilled in the art, there will be changes in the specific implementation methods and application scope based on the ideas of this application. Therefore, the content of this specification should not be construed as a limitation of this application.

Claims

1. A battery (10), characterized in that, include: A battery cell (11), wherein a tab assembly (13) is provided at the first end of the battery cell (11); An annular protective film (12) is disposed around the peripheral side of the battery cell (11). The inner walls of the first end of the annular protective film (12) are close to each other and connected to form a first sealing edge (1211) for sealing the battery cell (11). The inner walls of the second end of the annular protective film (12) opposite to the first end are close to each other and connected to form a second sealing edge (1212) for sealing the battery cell (11). The tab assembly (13) extends from the first sealing edge (1211) of the annular protective film (12) to the outside of the annular protective film (12).

2. The battery (10) according to claim 1, characterized in that, The second sealing edge (1212) has a folded edge (122) that folds toward the direction of the battery cell (11).

3. The battery (10) according to claim 2, characterized in that, Along the height direction of the battery (10), the maximum height L of the annular protective film (12) and the maximum height A of the folded edge (122) satisfy the following relationship: 0.005 ≤ A / L ≤ 0.5; and / or, Along the height direction of the battery (10), the maximum height A of the folded edge (122) satisfies the relationship 0.8mm≤A≤4mm; and / or, The maximum thickness H1 of the annular protective film (12) is greater than the maximum thickness H2 of the folded edge (122).

4. The battery (10) according to claim 2, characterized in that, The folded edge (122) abuts against the outer peripheral surface of the annular protective film (12); and / or, An adhesive layer exists between the folded edge (122) and the annular protective film (12).

5. The battery (10) according to claim 1, characterized in that, The maximum width W of the annular protective film (12) along the width direction of the battery (10) and the maximum height L of the annular protective film (12) along the height direction of the battery (10) satisfy the following relationship: L > W / 2.

6. The battery (10) according to any one of claims 1 to 5, characterized in that, The annular protective film (12) includes at least an insulating fusion bonding layer (123), which are close to each other and connected to form the first sealing edge (1211) and the second sealing edge (1212) for sealing the battery cell (11).

7. The battery (10) according to claim 6, characterized in that, The annular protective film (12) is further provided with a barrier layer (124) and a protective layer (125). The barrier layer (124) is bonded to the outer surface of the insulating fusion bonding layer (123), and the protective layer (125) is bonded to the outer surface of the barrier layer (124).

8. The battery (10) according to claim 7, characterized in that, The annular protective film (12) includes a circular annular protective film (12); and / or, The insulating fusion bonding layer (123) comprises at least one of a polypropylene layer, a polyethylene terephthalate layer, a polyethylene layer, and an ethylene acrylate layer; and / or, The barrier layer (124) includes at least one of an aluminum layer, an aluminum alloy layer, and a copper alloy layer; and / or, The protective layer (125) includes at least one of a polyamide layer and a polyethylene terephthalate layer.

9. The battery (10) according to claim 6, characterized in that, An insulating adhesive layer (131) is provided on the outer periphery of the tab assembly (13), and the insulating fusion adhesive layer (123) is bonded to the insulating adhesive layer (131).

10. The battery (10) according to any one of claims 1 to 5, characterized in that, The annular protective film (12) is integrally formed; or, The annular protective film (12) includes a square body (129), and a first adhesive part (127) and a second adhesive part (128) are respectively provided at opposite ends of the square body (129). The square body (129) is bonded by the first adhesive part (127) and the second adhesive part (128).

11. A battery module (1), characterized in that, The battery module (1) includes the battery (10) according to any one of claims 1 to 10.

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