Battery cell and battery pack

Abstract

The application provides a battery monomer and a battery pack, and relates to the technical field of batteries. In the battery monomer, at least part of the sealing cover is located in the groove, and the edge of the sealing cover is welded with the end wall of the shell to seal the groove, so that the sealing of the battery monomer is formed; on this basis, the welding exhaust area is arranged on the edge of the sealing cover, so that when the edge of the sealing cover is welded with the end wall, the gasification gas can be helped to escape from the welding pool, the risk of pores is reduced, the reliability of the welding sealing of the sealing cover and the shell is improved, and the sealing performance of the battery monomer is helped to be improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell and a battery pack. Background Technology

[0002] The information disclosed in this background section is intended only to enhance the understanding of the general background of this disclosure and should not be construed as an admission or in any way implying that the information constitutes prior art known to those skilled in the art.

[0003] In a single battery cell, when the sealing cap is welded to the casing, the welded area is subjected to the high temperature of the welding heat source. The volatile components in the material are prone to vaporization. Because the solidification rate of the weld pool is relatively fast, the gas generated by vaporization is difficult to escape in time, thus forming pore defects inside the weld, which is not conducive to the reliability of the weld seal. Summary of the Invention

[0004] In view of this, the purpose of this application is to provide a battery cell and a battery pack, which aims to solve the technical problem of how to improve the reliability of the welding seal between the sealing cover and the housing.

[0005] To solve the above-mentioned technical problems, the technical solution adopted in this application is as follows: In a first aspect, embodiments of this application provide a battery cell having a first orientation. The battery cell includes: a housing, including a side wall and an end wall, the end wall being connected to one end of the side wall along the first orientation; an electrode assembly located within the housing, the end wall having a communicating groove and an injection hole, the injection hole being located between the electrode assembly and the groove along the first orientation; and a sealing cap, at least a portion of which is located within the groove, the sealing cap including an edge, the edge being welded to the end wall to seal the groove, the edge having a weld venting area.

[0006] In some embodiments of the first aspect, the edge includes a first welding surface, a second welding surface, and a ramp surface. The first welding surface is located on the side of the sealing cap facing away from the electrode assembly along the first direction. The second welding surface and the ramp surface are both located on the outer periphery of the sealing cap, and the ramp surface is located on the side of the sealing cap facing the electrode assembly along the first direction. The second welding surface is connected to both the ramp surface and the first welding surface. Both the first welding surface and the second welding surface are welded to the end wall. At least one of the first welding surface, the second welding surface, and the ramp surface has a welding venting area.

[0007] In some embodiments of the first aspect, the welding venting zone is a notch formed on the first welding surface and the second welding surface.

[0008] In some embodiments of the first aspect, the welding venting zone is a first slot formed on the first welding surface, the first slot being spaced apart from the ramp surface.

[0009] In some embodiments of the first aspect, the welding venting zone is a second slot formed on the slope surface, the second slot being spaced apart from the first welding surface.

[0010] In some embodiments of the first aspect, the welding venting zone is a blind hole formed on the slope surface, the blind hole being spaced apart from the first welding surface.

[0011] In some embodiments of the first aspect, the welding venting zone is a through hole opened on the second welding surface, the sealing cover is provided with a relief groove, the relief groove is disposed toward the electrode assembly and communicates with the liquid injection hole, and the through hole communicates with the relief groove.

[0012] In some embodiments of the first aspect, the end wall includes an interconnected arcuate surface and a bevel, the bevel being located between the arcuate surface and the electrode assembly along the first direction, the arcuate surface and the bevel forming a portion of the groove, and both the first welding surface and the second welding surface being welded to the arcuate surface.

[0013] In some embodiments of the first aspect, the angle formed by the inclined surface and the first welding surface is a first angle, and the angle formed by the slope surface and the first welding surface is a second angle, wherein the second angle is smaller than the first angle.

[0014] In some embodiments of the first aspect, the number of welding venting zones is multiple, and the multiple welding venting zones are arranged circumferentially spaced along the sealing cover.

[0015] Secondly, embodiments of this application provide a battery pack including the battery cells described in any of the embodiments of the first aspect above.

[0016] The beneficial effects of this application are as follows: In the battery cell provided in this application, at least a portion of the sealing cap is located within a groove, and the edge of the sealing cap is welded to the end wall of the casing to seal the groove, thereby forming a seal for the battery cell. Furthermore, by providing a welding venting area at the edge of the sealing cap, when the edge of the sealing cap is welded to the end wall, it helps the vaporized gas to escape from the weld pool, reducing the risk of porosity defects and improving the reliability of the welding seal between the sealing cap and the casing, thereby helping to improve the sealing performance of the battery cell. Attached Figure Description

[0017] To more clearly illustrate the technical solutions of the embodiments of this application, the accompanying drawings used in the embodiments will be briefly introduced below. It should be understood that the following drawings only show some embodiments of this application and should not be regarded as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort.

[0018] Figure 1 A schematic diagram of the three-dimensional structure of a single battery cell in an embodiment of this application is shown. Figure 1 ; Figure 2 A schematic diagram of the three-dimensional structure of a single battery cell in an embodiment of this application is shown. Figure 2 ; Figure 3 It shows Figure 2 A cross-sectional view of a single battery cell; Figure 4 It shows Figure 3 Enlarged structural diagram of region A in the middle; Figure 5 It shows Figure 4 A magnified structural diagram of region B in the middle; Figure 6 It shows Figure 2 A schematic diagram of the decomposed structure; Figure 7 A schematic cross-sectional view of the sealing cap in an embodiment of this application is shown. Figure 1 ; Figure 8 It shows Figure 7 A magnified structural diagram of region C in the middle; Figure 9 A schematic cross-sectional view of the sealing cap in an embodiment of this application is shown. Figure 2 ; Figure 10 It shows Figure 9 A magnified structural diagram of region D in the middle; Figure 11 A schematic cross-sectional view of the sealing cap in an embodiment of this application is shown. Figure 3 ; Figure 12 It shows Figure 11 A magnified structural diagram of region E in the middle; Figure 13 A schematic cross-sectional view of the sealing cap in an embodiment of this application is shown. Figure 4 ; Figure 14 It shows Figure 13 A magnified structural diagram of region F in the middle; Figure 15 A schematic cross-sectional view of the sealing cap in an embodiment of this application is shown. Figure 5 ; Figure 16 It shows Figure 15 A magnified structural diagram of region G in the middle.

[0019] Explanation of key component symbols: 100 - Battery cell; 110 - Housing; 111 - Side wall; 112 - End wall; 1121 - Groove; 1122 - Liquid injection hole; 1123 - Arc surface; 1124 - Bevel; 120 - Electrode assembly; 130 - Sealing cap; 131 - First welding surface; 132 - Second welding surface; 133 - Sloping surface; 134 - Weld venting area; 1341 - Notch; 1342 - First slot; 1343 - Second slot; 1344 - Blind hole; 1345 - Through hole; 135 - Clearance groove; 140 - End cap; 150 - Terminal post; α - First included angle; β - Second included angle; Z - First direction; X - Second direction. Detailed Implementation

[0020] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.

[0021] In the description of this application, the terms "center", "longitudinal", "lateral", "length", "width", "height", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.

[0022] Furthermore, unless otherwise explicitly specified and limited, "above" or "below" the second feature can mean that the first and second features are in direct contact, or that they are in indirect contact through an intermediate medium. Moreover, "above" or "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. "Below" or "below" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0023] In the description of this application, the terms "first," "second," etc., are used to distinguish different objects and should not be construed as indicating or implying a specific order or hierarchy, or implicitly specifying the number of technical features indicated. Therefore, a feature marked "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this application, the term "multiple" means two or more, unless otherwise explicitly defined.

[0024] In the description of this application, unless otherwise explicitly specified, the term "connection" should be interpreted broadly. For example, it can refer to a non-detachable connection, a detachable connection, or a single-piece structure; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can refer to the internal communication of two components or the interaction between two components. Those skilled in the art can understand the specific meaning of the above terms in this application according to the specific circumstances.

[0025] In the description of this application, "parallel" includes not only the case of absolute parallelism, but also the case of approximate parallelism as commonly understood in engineering; similarly, "perpendicular" also includes not only the case of absolute perpendicularity, but also the case of approximate perpendicularity as commonly understood in engineering. For example, two directions with an angle of 80° to 90° can be considered perpendicular; two directions with an angle of 0° to 10° can be considered parallel. Furthermore, the character " / " generally indicates an "or" relationship between related objects.

[0026] In a battery cell, when the sealing cap is welded to the casing, the welded area is subjected to the high temperature of the welding heat source. Volatile components in the material (such as residual solvents, adsorbed gases, and volatiles in the substrate) are prone to vaporization. Due to the fast solidification rate of the weld pool, the gas generated by vaporization is difficult to escape from the weld pool in time, thus forming pore defects inside the weld. Such defects are not conducive to the reliability of the sealing between the sealing cap and the casing, leading to the risk of leakage in the battery cell during use.

[0027] like Figure 1 As shown, to solve the above-mentioned technical problems, embodiments of this application provide a battery cell 100, which relates to the field of battery technology and is mainly applied to battery packs, so as to be indirectly applied to electrical devices and energy storage devices in the form of battery packs. Of course, the battery cell 100 can also be directly applied to electrical devices and energy storage devices without taking the form of a battery pack.

[0028] For example, electrical equipment can be vehicles, mobile phones, computers, ships, spacecraft, power tools, electric toys, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, new energy vehicles, etc., and new energy vehicles can be pure electric vehicles, hybrid electric vehicles, range-extended electric vehicles, etc.; spacecraft can be airplanes, rockets, drones, spacecraft, etc.; electric toys can be game consoles, electric car toys, electric ship toys, electric airplane toys, etc.; power tools can be metal cutting power tools, grinding power tools, assembly power tools, railway power tools, etc., specifically such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. Energy storage equipment can be energy storage containers, energy storage cabinets, energy storage power stations, wind power generation devices, solar power generation devices, mobile power devices, temporary power supply devices, etc.

[0029] It should be noted that the battery cell 100 mainly relies on the migration of metal ions between the positive and negative electrodes to function. The battery cell 100 can be rectangular, cylindrical, flat, or other shapes. Classified by packaging method, the battery cell 100 can be a square battery, a cylindrical battery, etc.; classified by the type of metal ions, the battery cell 100 can be a lithium-ion battery, a sodium-ion battery, etc.; classified by the physical state of the electrolyte, the battery cell 100 can be a liquid battery, i.e., using a liquid electrolyte (electrolyte); of course, the battery cell 100 can also be a solid-state battery or a semi-solid-state battery, i.e., the electrolyte is at least partially solid-state, with common materials such as sulfide, oxide, or polymer electrolytes. The solid-state electrolyte can replace the liquid electrolyte and the separator layer between the positive and negative electrodes, providing both ion conduction and isolation functions.

[0030] like Figure 2 , Figure 3 and Figure 6 As shown, the battery cell 100 provided in this embodiment has a first direction Z. The battery cell 100 includes: a housing 110, an electrode assembly 120, and a sealing cap 130.

[0031] The housing 110 includes a side wall 111 and an end wall 112, with the end wall 112 connected to one end of the side wall 111 along a first direction Z. The electrode assembly 120 is located inside the housing 110. The end wall 112 is provided with a groove 1121 and a liquid injection hole 1122 that are in communication with each other. The liquid injection hole 1122 is located between the electrode assembly 120 and the groove 1121 along the first direction Z. At least a portion of the sealing cap 130 is located inside the groove 1121. The sealing cap 130 includes an edge 130A, which is welded to the end wall 112 to cover the groove 1121. The edge 130A is provided with a welding venting area 134.

[0032] It is understood that in the battery cell 100 provided in this embodiment, at least a portion of the sealing cap 130 is located within the groove 1121, and the edge 130A of the sealing cap 130 is welded to the end wall 112 of the housing 110 to seal the groove 1121, thereby forming a seal for the battery cell 100. On this basis, by providing a welding venting area 134 at the edge 130A of the sealing cap 130, when the edge 130A of the sealing cap 130 is welded to the end wall 112, it helps the vaporized gas to escape from the weld pool, reducing the risk of porosity defects and improving the reliability of the weld seal between the sealing cap 130 and the housing 110, thereby helping to improve the sealing performance of the battery cell 100.

[0033] Furthermore, by positioning the weld venting zone 134 at the edge 130A of the sealing cover 130, the adverse effects on the structural strength of the sealing cover 130 are minimized, which helps to improve the reliability of the sealing cover 130 in use.

[0034] like Figures 1 to 3 As shown, in some embodiments, the battery cell 100 further includes an end cap 140 and a terminal post 150 passing through the end cap 140. The end cap 140 is connected to the end of the side wall 111 away from the end wall 112 along a first direction Z. Both the terminal post 150 and the end wall 112 are electrically connected to the electrode assembly 120. Thus, one of the terminal post 150 and the housing 110 serves as the positive terminal of the external circuit, and the other of the terminal post 150 and the housing 110 serves as the negative terminal of the external circuit.

[0035] For example, the material of the sealing cap 130, the end cap 140, and the housing 110 can be aluminum, aluminum alloy, copper, steel, titanium, etc., without specific limitations.

[0036] It should be noted that the electrode assembly 120 may include a positive electrode sheet, a negative electrode sheet, and an insulating layer, and is manufactured using a winding process or a stacking process. The insulating layer is disposed between the positive electrode sheet and the negative electrode sheet. The positive electrode sheet includes a positive current collector and a positive active material layer, with the positive active material layer coated on the positive current collector. The negative electrode sheet includes a negative current collector and a negative active material layer, with the negative active material layer coated on the negative current collector. The portion of the positive current collector not coated with the positive active material layer is the positive tab, and the portion of the negative current collector not coated with the negative active material layer is the negative tab.

[0037] One of the positive and negative tabs is electrically connected to the pole post 150, and the other of the positive and negative tabs is electrically connected to the end wall 112, thereby enabling the housing 110 and the pole post 150 to serve as the positive and negative poles of the external circuit, respectively.

[0038] For example, the material of the separator layer can be polypropylene, polyethylene, etc.; taking lithium ions as an example, the material of the positive electrode current collector can be aluminum, and the material of the positive electrode active material layer can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, lithium manganese oxide, etc.; the material of the negative electrode current collector can be copper, and the negative electrode active material can be graphite, silicon, etc., without making specific limitations on the above materials.

[0039] like Figures 2 to 6 As shown, in some embodiments, edge 130A includes a first welding surface 131, a second welding surface 132, and a ramp surface 133. The first welding surface 131 is located on the side of the sealing cap 130 facing away from the electrode assembly 120 along the first direction Z. The second welding surface 132 and the ramp surface 133 are both located on the outer periphery of the sealing cap 130, and the ramp surface 133 is located on the side of the sealing cap 130 facing the electrode assembly 120 along the first direction Z. The second welding surface 132 is connected to the ramp surface 133 and the first welding surface 131 respectively. The first welding surface 131 and the second welding surface 132 are both welded to the end wall 112. At least one of the first welding surface 131, the second welding surface 132, and the ramp surface 133 is provided with a welding venting area 134.

[0040] It is understood that in the battery cell 100 provided in this embodiment, at least a portion of the sealing cap 130 is located in the groove 1121. The first welding surface 131 and the second welding surface 132 of the sealing cap 130 are both welded to the end wall 112 of the housing 110 to seal the groove 1121, thereby forming a seal on the battery cell 100. During the process of installing the sealing cap 130 into the groove 1121, the slope surface 133 of the sealing cap 130 plays a guiding role, reducing the installation difficulty of the sealing cap 130.

[0041] Based on this, by providing a welding venting zone 134 in at least one of the first welding surface 131, the second welding surface 132, and the ramp surface 133, when the first welding surface 131 and the second welding surface 132 are welded to the end wall 112, it helps the vaporized gas to escape from the weld pool, reduces the risk of porosity defects, improves the reliability of the welded seal between the sealing cap 130 and the housing 110, and thus helps to improve the sealing performance of the battery cell 100.

[0042] like Figure 7 and Figure 8 As shown, in some specific embodiments, the welding venting zone 134 is a notch 1341 formed on the first welding surface 131 and the second welding surface 132.

[0043] Understandably, when the first welding surface 131 and the second welding surface 132 are welded to the end wall 112, the notch 1341 opened on the first welding surface 131 and the second welding surface 132 helps the vaporized gas escape from the weld pool and can disperse the vaporized gas to the external environment. In addition, the notch 1341 is easier to process and has a lower processing cost.

[0044] It should be noted that when the welding venting zone 134 is a notch 1341, the welding trajectory will pass through the notch 1341, and the final weld will cover the notch 1341.

[0045] like Figure 9 and Figure 10 As shown, in some other specific embodiments, the welding venting zone 134 is a first slot 1342 formed on the first welding surface 131, and the first slot 1342 is spaced apart from the ramp surface 133.

[0046] Understandably, when the first welding surface 131 and the second welding surface 132 are welded to the end wall 112, the first slot 1342 opened on the first welding surface 131 also helps the vaporized gas escape from the weld pool and can disperse the vaporized gas to the external environment.

[0047] like Figure 11 and Figure 12 As shown, in some specific embodiments, the welding venting zone 134 is a second slot 1343 formed on the slope surface 133, and the second slot 1343 is spaced apart from the first welding surface 131.

[0048] Understandably, when the first welding surface 131 and the second welding surface 132 are welded to the end wall 112, the second slot 1343 opened on the slope surface 133 also helps the gasified gas to escape from the weld pool and can disperse the gasified gas into the groove 1121.

[0049] like Figure 13 and Figure 14 As shown, in some specific embodiments, the welding venting zone 134 is a blind hole 1344 opened on the slope surface 133, and the blind hole 1344 is spaced apart from the first welding surface 131.

[0050] Understandably, when the first welding surface 131 and the second welding surface 132 are welded to the end wall 112, the blind hole 1344 opened on the slope surface 133 also helps the vaporized gas escape from the weld pool and can disperse the vaporized gas into the groove 1121. In addition, the blind hole 1344 is easier to process and has a lower processing cost.

[0051] like Figure 15 and Figure 16As shown, in some other specific embodiments, the welding venting zone 134 is a through hole 1345 opened on the second welding surface 132, the sealing cover 130 is provided with a relief groove 135, the relief groove 135 is disposed toward the electrode assembly 120 and communicates with the liquid injection hole 1122, and the through hole 1345 communicates with the relief groove 135.

[0052] Understandably, when the end wall 112 is electrically connected to the electrode assembly 120 via welding, the clearance groove 135 provides space to avoid the weld, reducing the risk of interference between the weld and the sealing cap 130. When the first welding surface 131 and the second welding surface 132 are welded to the end wall 112, the through hole 1345 on the second welding surface 132 also facilitates the escape of vaporized gas from the weld pool and can disperse the vaporized gas into the clearance groove 135. Furthermore, the through hole 1345 is easier and cheaper to manufacture.

[0053] like Figures 2 to 5 As shown, the end wall 112 further includes an arc surface 1123 and an inclined surface 1124 connected to each other. The inclined surface 1124 is located between the arc surface 1123 and the electrode assembly 120 along the first direction Z. The arc surface 1123 and the inclined surface 1124 form part of the groove 1121. The first welding surface 131 and the second welding surface 132 are both welded to the arc surface 1123.

[0054] Understandably, during the installation of the sealing cap 130 into the groove 1121, the combination of the arc surface 1123 and the inclined surface 1124 plays a further guiding role, reducing the installation difficulty of the sealing cap 130.

[0055] like Figure 5 As shown, further, the angle formed by the inclined surface 1124 and the first welding surface 131 is the first included angle α, and the angle formed by the inclined surface 133 and the first welding surface 131 is the second included angle β, where the second included angle β is smaller than the first included angle α. This provides clearance space for the inclined surface 133, improving the situation where the sealing cover 130 is difficult to install due to processing errors, and reducing the installation difficulty of the sealing cover 130.

[0056] like Figure 7 As shown, in some embodiments, there are multiple welding venting zones 134, which are spaced apart circumferentially along the sealing cover 130.

[0057] It is understandable that, since the weld formed by welding the edge 130A of the sealing cover 130 to the end wall 112 is a ring structure, that is, the weld surrounds the sealing cover 130, by setting multiple welding venting zones 134, which are spaced apart along the circumference of the sealing cover 130, the vaporized gas can be guided out of the weld pool at multiple locations, thereby more effectively reducing the risk of porosity defects.

[0058] It should be noted that the battery cell 100 also has a second direction X perpendicular to the first direction Z. When the battery cell 100 is a cylindrical battery, the first direction Z is the axial direction of the cylindrical battery, and the second direction X is the diameter direction of the cylindrical battery. When the battery cell 100 is a square battery, the first direction Z is the height direction of the square battery, and the second direction X is the length or width direction of the square battery.

[0059] To address the aforementioned technical problems, embodiments of this application also provide a battery pack, including the battery cell 100 from any of the above embodiments.

[0060] It is understood that since the battery pack provided in this embodiment includes the battery cell 100 in any of the above embodiments, it has all the beneficial effects of the battery cell 100, which will not be described in detail here.

[0061] In the description of this application, the terms "some embodiments," "one embodiment," "example," "specific example," "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In the description of this application, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples. Furthermore, without contradiction, those skilled in the art can combine and integrate the different embodiments or examples described in this specification, as well as the features of different embodiments or examples.

[0062] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application.

Claims

1. A battery cell, characterized in that, Having a first orientation (Z), the battery cell includes: The housing (110) includes a side wall (111) and an end wall (112), the end wall (112) being connected to one end of the side wall (111) along the first direction (Z); An electrode assembly (120) is located inside the housing (110). The end wall (112) is provided with a groove (1121) and a liquid injection hole (1122) that are interconnected. The liquid injection hole (1122) is located between the electrode assembly (120) and the groove (1121) along the first direction (Z). A sealing cap (130) is located at least partly within the groove (1121). The sealing cap (130) includes an edge (130A) which is welded to the end wall (112) to seal the groove (1121). The edge (130A) is provided with a weld venting area (134).

2. The battery cell according to claim 1, characterized in that, The edge (130A) includes a first welding surface (131), a second welding surface (132), and a ramp surface (133). The first welding surface (131) is located on the side of the sealing cap (130) facing away from the electrode assembly (120) along the first direction (Z). The second welding surface (132) and the ramp surface (133) are both located on the outer periphery of the sealing cap (130), and the ramp surface (133) is located on the side of the sealing cap (130) facing the electrode assembly (120) along the first direction (Z). The second welding surface (132) is connected to the ramp surface (133) and the first welding surface (131) respectively. The first welding surface (131) and the second welding surface (132) are both welded to the end wall (112). At least one of the first welding surface (131), the second welding surface (132), and the ramp surface (133) is provided with a welding venting area (134).

3. The battery cell according to claim 2, characterized in that, The welding venting zone (134) is an opening (1341) formed on the first welding surface (131) and the second welding surface (132).

4. The battery cell according to claim 2, characterized in that, The welding venting zone (134) is a first slot (1342) opened on the first welding surface (131), and the first slot (1342) is spaced apart from the slope surface (133).

5. The battery cell according to claim 2, characterized in that, The welding venting zone (134) is a second slot (1343) opened on the slope surface (133), and the second slot (1343) is spaced apart from the first welding surface (131).

6. The battery cell according to claim 2, characterized in that, The welding venting zone (134) is a blind hole (1344) opened on the slope surface (133), and the blind hole (1344) is spaced apart from the first welding surface (131).

7. The battery cell according to claim 2, characterized in that, The welding venting zone (134) is a through hole (1345) opened on the second welding surface (132). The sealing cover (130) is provided with a relief groove (135). The relief groove (135) is arranged facing the electrode assembly (120) and communicates with the liquid injection hole (1122). The through hole (1345) communicates with the relief groove (135).

8. The battery cell according to claim 2, characterized in that, The end wall (112) includes an interconnected arc surface (1123) and a slope (1124), the slope (1124) being located between the arc surface (1123) and the electrode assembly (120) along the first direction (Z), the arc surface (1123) and the slope (1124) forming a part of the groove (1121), and the first welding surface (131) and the second welding surface (132) being welded to the arc surface (1123).

9. The battery cell according to claim 8, characterized in that, The angle formed by the inclined surface (1124) and the first welding surface (131) is the first included angle (α), and the angle formed by the inclined surface (133) and the first welding surface (131) is the second included angle (β), which is smaller than the first included angle (α).

10. The battery cell according to claim 1, characterized in that, The number of welding venting zones (134) is multiple, and the multiple welding venting zones (134) are arranged at circumferential intervals along the sealing cover (130).

11. A battery pack, characterized in that, Includes the battery cell according to any one of claims 1 to 10.

Images