Battery monomer, battery device and electric device

Abstract

The utility model belongs to the technical field of battery production, and provides a battery monomer, a battery device and a power utilization device.The battery monomer comprises a shell, a cover body and an electrode assembly, the cover body is connected to the shell, and the cover body and the shell jointly define a containing cavity; the cover body comprises a first part, a second part and a bending part, the first part protrudes in the direction away from the electrode assembly relative to the second part, and the bending part is connected with the first part and the second part; the first part, the second part and the bending part are all welded with the shell, the welding fusion part between the bending part and the shell has a bending fusion depth, the welding fusion part between the first part and the shell has a first fusion depth, the welding fusion part between the second part and the shell has a second fusion depth, the bending fusion depth is larger than or smaller than the first fusion depth, and the bending fusion depth is larger than or smaller than the second fusion depth. And the bending fusion depth is greater than or less than the second fusion depth. The welding quality between the cover body and the shell is improved, and the welding cost is optimized.

Description

Technical Field

[0001] This application relates to the field of battery manufacturing technology, and in particular to a battery cell, battery device, and power-consuming device. Background Technology

[0002] Among the many types of rechargeable batteries, convex-pack batteries, due to their unique structural design, can improve the utilization rate of the battery's internal space to a certain extent, thus showing advantages in some specific application scenarios.

[0003] The outer casing of a convex battery consists of a shell and a cover, which are fixed together by welding. The cover has an outwardly protruding part, which forms a bent part. The connection between the bent part and the shell also needs to be welded.

[0004] In related technologies, the welding standards for the bends and other parts on the cover and the shell are uniformly adopted at different locations. This makes the welding too rigid, which can easily lead to welding failures between the bends and the shell, or increase welding costs. This results in a trade-off between welding strength and cost optimization when welding the cover and the shell of the convex battery. Utility Model Content

[0005] The purpose of this application is to provide a battery cell, a battery device, and an electrical device, which aims to solve the technical problem of the mutual constraint between welding strength and cost optimization when welding the cover and the casing of a convex battery.

[0006] In a first aspect, this application provides a battery cell, comprising:

[0007] case;

[0008] A cover is attached to a housing and together with the housing to form a receiving cavity; the cover includes a first part, a second part and a bent part, the first part protrudes relative to the second part in a direction away from the receiving cavity, and the bent part connects the first part and the second part.

[0009] An electrode assembly is housed within a receiving cavity, and the electrode assembly is disposed opposite to the first part and the second part.

[0010] The first part, the second part, and the bent part are all welded to the shell and respectively form the first welded part, the second welded part, and the bent welded part. The bent welded part has a bending penetration depth, the first welded part has a first penetration depth, and the second welded part has a second penetration depth. The bending penetration depth is greater than or less than the first penetration depth, and the bending penetration depth is greater than or less than the second penetration depth.

[0011] In this embodiment, the special characteristics of the stress at the connection between the bent part and the shell are fully considered. Therefore, depending on whether the welding strength between the bent part and the shell can become a bottleneck for welding failure, the bending penetration depth between the bent part and the shell can be adjusted relative to the first penetration depth between the first part and the shell and the second penetration depth relative to the second part and the shell. A flexible welding penetration depth design is adopted to find a balance point (or balance range) between welding quality and cost optimization, thereby improving the welding quality between the cover and the shell and optimizing the welding cost.

[0012] In one embodiment, the bending depth is less than the first depth of penetration and less than the second depth of penetration.

[0013] In this embodiment, by reducing the weld penetration depth of the portion where the bent part and the shell are welded together, it is possible to reduce production costs while ensuring the welding strength and quality between the bent part and the shell.

[0014] In one embodiment, the bending depth ranges from 0.2mm to 0.6mm; the first depth ranges from 0.61mm to 1.5mm; the first depth ranges from 0.61mm to 1.5mm.

[0015] In this embodiment, by controlling the specific numerical ranges of the bending penetration depth, the first penetration depth, and the second penetration depth, it is beneficial to achieve precise control of the welding strength of the first welded part, the second welded part, and the bending welded part, thereby improving reliability.

[0016] In one embodiment, the bending depth is greater than the first depth of penetration and the bending depth of penetration is greater than the second depth of penetration.

[0017] In this embodiment, by increasing the weld penetration depth of the portion where the bent part and the shell are welded together, the welding strength and quality between the bent part and the shell can be guaranteed while keeping the increase in production costs relatively small.

[0018] In one embodiment, the bending depth ranges from 0.61mm to 1.5mm; the first depth ranges from 0.2mm to 0.6mm; and the second depth ranges from 0.2mm to 0.6mm.

[0019] In this embodiment, by controlling the specific numerical ranges of the bending penetration depth, the first penetration depth, and the second penetration depth, it is beneficial to achieve precise control of the welding strength of the first welded part, the second welded part, and the bending welded part, thereby improving reliability.

[0020] In one embodiment, the first melting depth is equal to the second melting depth.

[0021] In this embodiment, both the first part and the second part are welded to the shell with the same depth of penetration, which helps to improve the quality of welding, reduce the difficulty of welding, and improve the consistency of welding between the cover and the shell.

[0022] In one embodiment, the battery cell further includes an adapter and an electrode terminal. The electrode terminal is disposed in the second part, and the electrode assembly has a tab disposed opposite to the first part. The tab is connected to the electrode terminal through the adapter. The first part protrudes relative to the second part in a first direction, and a third welded part is formed between the tab and the adapter. In a second direction, the third welded part has at least a portion opposite to the bent part. The second direction is perpendicular to the first direction.

[0023] In this embodiment, by making the third welding part and the bending part form overlapping projected areas in the second direction, it is beneficial to increase the volume of the electrode assembly, thereby improving the energy density of the battery cell.

[0024] In one embodiment, the bending portion includes a first bending portion, a straight portion, and a second bending portion. The straight portion is connected between the first bending portion and the second bending portion. The first bending portion is connected to a first part, and the second bending portion is connected to a second part. The portion of the first bending portion that is welded to the shell has a first sub-melt depth. The portion of the second bending portion that is welded to the shell has a second sub-melt depth. The portion of the straight portion that is welded to the shell has a third sub-melt depth. Both the first sub-melt depth and the second sub-melt depth are greater than the third sub-melt depth.

[0025] In this embodiment, increasing the weld penetration between the first and second curved portions and the shell helps to disperse stress, improve welding strength, and reduce the risk of weld cracking.

[0026] In one embodiment, the first sub-melt depth is equal to the second sub-melt depth.

[0027] In this embodiment, both the first part and the second part are welded to the shell with the same depth of penetration, which helps to improve the quality of welding, reduce the difficulty of welding, and improve the consistency of welding between the bent part and the shell.

[0028] In one embodiment, the side edge of the cover extends to the outer side of the housing so that the housing is welded to the cover on the outer side.

[0029] In this embodiment, the position where the cover is welded to the shell is located on the side of the shell, which allows the welding equipment to be located on the side of the shell, thus protecting the welding position and improving the convenience of welding.

[0030] In one embodiment, the housing is attached to the side edge of the cover and extends to the top surface of the cover so that the housing is welded to the cover at the top.

[0031] In this embodiment, the cover and the shell are welded at the top, which helps to improve the shell's ability to enclose the cover and improves the weld strength between the shell and the cover.

[0032] In one embodiment, there are two second parts, with the first part connected between the two second parts, and each second part forming a bend at the position where it connects to the first part.

[0033] In this embodiment, by setting two second parts, the first part can be located in the middle of the cover. The explosion-proof valve can be connected to the middle of the first part, and the gas generated by the electrode assembly can converge symmetrically to the explosion-proof valve, which facilitates the smooth discharge of the gas.

[0034] In one embodiment, the electrode assembly has tabs that are disposed opposite to the first portion.

[0035] In this embodiment, the tab is positioned opposite the first part, thereby creating redundant space on the outer casing for the protruding first part. This space is used to accommodate the tab, which helps to increase the volume of the electrode assembly and thus improve the energy density of the battery cell.

[0036] In one embodiment, the battery cell also includes an electrode terminal connected to the second portion.

[0037] In this embodiment, the electrode terminals are connected to the second part, thereby enabling the first part to make full use of the space on both sides of the protruding portion of the electrode terminals and improve the space utilization rate of the battery cell.

[0038] In one embodiment, the first adapter and the second adapter are arranged in a staggered manner, such that the first adapter and the electrode terminal form an overlapping area along a second direction, which is perpendicular to the first direction.

[0039] Secondly, this application provides a battery device, which includes a battery cell as described in any of the above.

[0040] Thirdly, this application provides an electrical device, including a battery cell or battery device as described above, wherein the battery device is used to store or provide electrical energy.

[0041] The above description is only an overview of the technical solution of this application. In order to better understand the technical means of this application and to implement it in accordance with the contents of the specification, and to make the above and other objects, features and advantages of this application more obvious and understandable, the following are specific embodiments of this application. Attached Figure Description

[0042] To more clearly illustrate the technical solutions of the embodiments of this application, the drawings used in the description of the embodiments of this application or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This application provides structural schematic diagrams of vehicles for some embodiments;

[0044] Figure 2 This is an exploded view of the battery device provided in some embodiments of this application;

[0045] Figure 3 This is a schematic diagram of the structure of a battery cell provided in some embodiments of this application;

[0046] Figure 4 for Figure 3 AA or CC section view;

[0047] Figure 5 for Figure 4 A magnified view of a portion of the area at position D;

[0048] Figure 6 for Figure 3 BB section view in the middle;

[0049] Figure 7 for Figure 6 A magnified view of the area at position E in the middle;

[0050] Figure 8 for Figure 3 A magnified view of the area at position F;

[0051] Figure 9 for Figure 3 Top view;

[0052] Figure 10 for Figure 3 A schematic diagram of the decomposed structure;

[0053] Figure 11 for Figure 10 A schematic diagram of the exploded structure of the outer shell;

[0054] Figure 12 Cross-sectional views of a battery cell provided in some embodiments of this application;

[0055] Figure 13 for Figure 12 A magnified view of the area at position G.

[0056] Explanation of reference numerals in the attached figures:

[0057] 1000, Vehicle; 1100, Battery assembly; 1110, Housing; 1111, First housing section; 1112, Second housing section; 1113, Receiving space; 1120, Battery cell; 1121, Outer casing; 11211, Cover; 11212, Housing; 11213, Receiving cavity; 11214, First part; 11215, Second part; 11216, Bending part; 11217, First bending part; 11218, Second bending part; 11219, Straight part; 1122, Electrode assembly; 112 3. Electrode terminal; 1124. Explosion-proof valve; 1125. Electrode lug; 1126. Bending and welding part; 1127. First welding part; 1128. Second welding part; 1129. Adapter component; 1130. Third welding part; P0. Preset value; P1. Opening pressure; P2. Failure pressure; 1200. Controller; 1300. Motor; X. First direction; Y. Second direction; L1. Bending penetration depth; L2. First penetration depth; L3. Second penetration depth; H1. Projected height of the bending part; H2. Projected height of the third welding part. Detailed Implementation

[0058] The embodiments of the technical solution of this application will now be described in detail with reference to the accompanying drawings. These embodiments are only used to more clearly illustrate the technical solution of this application, and are therefore merely examples and should not be used to limit the scope of protection of this application.

[0059] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application pertains; the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the application; the terms “comprising” and “having”, and any variations thereof, in the specification, claims, and foregoing description of the drawings are intended to cover non-exclusive inclusion.

[0060] In the description of the embodiments of this application, technical terms such as "first" and "second" are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implicitly specifying the number, specific order, or primary and secondary relationship of the indicated technical features. In the description of the embodiments of this application, "multiple" means two or more, unless otherwise explicitly defined.

[0061] In this document, the term "embodiment" means that a particular feature, structure, or characteristic described in connection with an embodiment may be included in at least one embodiment of this application. The appearance of this phrase in various places throughout the specification does not necessarily refer to the same embodiment, nor is it a separate or alternative embodiment mutually exclusive with other embodiments. It will be explicitly and implicitly understood by those skilled in the art that the embodiments described herein can be combined with other embodiments.

[0062] In the description of the embodiments in this application, the term "and / or" is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this document generally indicates that the preceding and following related objects have an "or" relationship.

[0063] In the description of the embodiments of this application, the term "multiple" refers to two or more (including two), similarly, "multiple sets" refers to two or more (including two sets), and "multiple pieces" refers to two or more (including two pieces).

[0064] In the description of the embodiments of this application, the technical terms "center," "longitudinal," "lateral," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing the embodiments of this application and simplifying the description, and are not intended to 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 the embodiments of this application.

[0065] In the description of the embodiments of this application, unless otherwise expressly specified and limited, technical terms such as "installation," "connection," "joining," and "fixing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components. For those skilled in the art, the specific meaning of the above terms in the embodiments of this application can be understood according to the specific circumstances.

[0066] Against the backdrop of ever-increasing energy demand, rechargeable batteries, as important energy storage devices, are widely used in various electronic devices, electric vehicles, and energy storage systems. With the market's increasing demands for battery performance, developing highly reliable and high-performance rechargeable batteries has become a key task for the industry.

[0067] Among the many types of rechargeable batteries, convex-pack batteries, due to their unique structural design, can improve the utilization rate of the battery's internal space to a certain extent, thus showing advantages in some specific application scenarios.

[0068] The outer casing of a convex battery consists of a shell and a cover, which are fixed together by welding. The cover has an outwardly protruding part, which forms a bent part. The connection between the bent part and the shell also needs to be welded.

[0069] In related technologies, the welding standards for the bends and other parts on the cover to the shell are uniformly adopted at higher or lower levels. This does not take into account the special stress at the connection between the bend and the shell, making the welding too rigid. This results in welding failures between the bend and the shell, or increased welding costs. As a result, there is a trade-off between welding strength and cost optimization when welding the cover and the shell of the convex battery.

[0070] Therefore, this application further analyzes the aforementioned problems in detail. In existing secondary battery technologies, when the cover and casing are joined by a bending method, the stress concentration problem at the bending point is particularly prominent. Especially during battery production, transportation, and use, the bending point is subjected to various external forces, and stress concentration easily leads to a reduction in the weld strength at this point, thereby affecting the overall performance and service life of the battery. In related technologies, in order to improve the welding strength between the bending point and the casing, a uniform and high welding standard is used at the connection between the cover and the casing, resulting in an increase in welding costs. Therefore, when lowering the welding standard to reduce production costs, the stress at the bending point becomes a bottleneck, and the welding quality at the bending point cannot be guaranteed. This makes the battery prone to weld failure during use, thus causing a difficult-to-overcome contradiction between welding strength and cost optimization when welding the cover and casing.

[0071] Currently, there are many shortcomings in the solutions available on the market for this type of problem. Some existing technologies lack effective means to flexibly adjust the welding process according to the stress at the bending point of the battery cell during use. For example, uniformly adopting a high penetration depth standard increases production costs, or unreasonable penetration depth control makes it impossible to effectively guarantee weld quality when the stress at the bending point is the bottleneck, causing problems such as weld failure during battery use.

[0072] Therefore, based on the above-mentioned technical problems, this application provides a battery cell that designs different welding penetration depths for the bent portions of the casing and cover, as well as for the welding penetration depths for other parts of the casing and cover besides the bent portions. The welding penetration depths of the bent portions and other parts are flexibly adjusted according to the stress conditions of the bent portions. By adopting different and adaptive penetration depth designs, the effect of balancing welding quality and welding cost is achieved, thereby improving weld strength and optimizing production costs.

[0073] Specifically, refer to Figure 3-7 As shown, this application provides a battery cell 1120, which includes a housing 11212, a cover 11211, and an electrode assembly 1122. The cover 11211 is connected to the housing 11212 and together with the housing 11212 forms a receiving cavity 11213. The cover 11211 includes a first part 11214, a second part 11215, and a bent part 11216. The first part 11214 protrudes relative to the second part 11215 in a direction away from the receiving cavity 11213. The bent part 11216 connects the first part 11214 and the second part 11215. The electrode assembly 1122 is housed in the receiving cavity 11213. The first part 11214, the second part 11215, and the bent part 11216 are all welded to the housing 11212 and respectively form a first welding part 1127, a second welding part 1128, and a bent welding part 1126. The bent welding part 1126 has a bending penetration depth L1, the first welding part 1127 has a first penetration depth L2, and the second welding part 1128 has a second penetration depth L3. The bending penetration depth L1 is greater than or less than the first penetration depth L2, and the bending penetration depth L1 is greater than or less than the second penetration depth L3.

[0074] For the battery cell 1120, the battery cell 1120 is the most basic unit that constitutes the battery device 1100 or the battery system. The battery cell 1120 can directly convert chemical energy into electrical energy and has independent charging and discharging functions.

[0075] In this context, battery cell 1120 refers to the smallest unit that makes up battery device 1100. Each battery cell 1120 can be a secondary battery cell or a primary battery cell; it can also be a lithium-sulfur battery cell, a sodium-ion battery cell, or a magnesium-ion battery cell, but is not limited to these. Battery cell 1120 can be cylindrical, flat, cuboid, or other shapes.

[0076] Each battery cell 1120 includes one or more electrode assemblies 1122. An electrode assembly 1122 can be understood as a bare cell within the battery cell 1120. The electrode assembly 1122 is housed within a receiving cavity 11213 of the outer casing 1121. The electrode assembly 1122 is electrically connected to the electrode terminal 1123, or, alternatively, the electrode assembly 1122 is electrically connected to the electrode terminal 1123 via an adapter. For example, a tab 1125 is formed on the electrode assembly 1122, and the tab 1125 is welded to the adapter to achieve electrical connection between the tab 1125 and the adapter.

[0077] The housing 11212 and the cover 11211 are connected to form the outer shell 1121. The cover 11211 and the housing 11212 cover each other, and the cover 11211 and the housing 11212 together define a receiving cavity 11213 for accommodating the electrode assembly 1122. The housing 11212 can be a hollow structure with one end open, and the cover 11211 can be a plate-like structure. The cover 11211 covers the open side of the housing 11212, so that the cover 11211 and the housing 11212 together define the receiving cavity 11213. Alternatively, the cover 11211 and the housing 11212 can both be hollow structures with one side open, and the open side of the cover 11211 covers the open side of the housing 11212. The cover 11211 and the housing 11212 are fixed and sealed by welding. Of course, the outer shell 1121 formed by the cover 11211 and the shell 11212 can be of various shapes, such as a cylinder, a cuboid, etc.

[0078] The external shape of the battery cell 1120 is generally cylindrical or prismatic. Therefore, it is generally considered that for a prismatic battery, the battery cell 1120 has a height direction, and the direction perpendicular to the height direction can include the length direction and the width direction. Alternatively, for a cylindrical battery cell 1120, the direction perpendicular to the height direction can be considered radial, and the height direction can be called the axial direction. In the following example, a prismatic battery cell 1120 is used as an example for illustration. For ease of description, the height direction of the battery cell 1120 is defined as the first direction X, the length direction of the battery cell 1120 is defined as the second direction Y, and the width direction of the battery cell 1120 is defined as the third direction.

[0079] For the cover 11211, the cover 11211 includes a first part 11214 and a second part 11215 connected to each other. The first part 11214 and the second part 11215 are connected by a bending part 11216. When the cover 11211 is a plate-like structure, both the first part 11214 and the second part 11215 can be understood as a plate. (Refer to...) Figure 3As shown, the cover 11211 and the electrode assembly 1122 are arranged opposite to each other in the first direction X. That is, the first part 11214 and the second part 11215 of the cover 11211 are both arranged opposite to the electrode assembly 1122 in the first direction X. The first part 11214 and the second part 11215 of the cover 11211 are arranged left and right in the second direction Y. The first part 11214 protrudes in a direction away from the accommodating cavity 11213 and the electrode assembly 1122 relative to the second part 11215, so that the first part 11214 forms a protruding part on the cover 11211, so that the battery cell 1120 forms a convex battery that can improve the internal space utilization of the battery cell 1120. Generally, the first part 11214 can be designed to be opposite to the tab 1125 of the electrode assembly 1122, so that an additional space is formed on the cover 11211 to accommodate the tab 1125, thereby achieving the purpose of improving space utilization.

[0080] Because of the misalignment of the first part 11214 and the second part 11215 of the cover 11211 in the first direction X, a bend 11216 is formed between the first part 11214 and the second part 11215. It is understood that due to the misalignment of the first part 11214 and the second part 11215 in the first direction X, the bend 11216 is an inclined connection between the first part 11214 and the second part 11215. The first part 11214, the second part 11215, and the bend 11216 can be manufactured by integral molding, or the bend 11216 can be manufactured by stamping.

[0081] Specifically, the connection between the cover 11211 and the shell 11212 is as follows: the first part 11214, the second part 11215, and the bent part 11216 of the cover 11211 all need to be welded to the shell 11212. For the shell 11212, since it needs to be assembled and welded to the cover 11211, a protruding first sidewall portion is formed on the shell 11212 (specifically, the sidewall of the shell 11212) corresponding to the first part 11214; a protruding second sidewall portion is formed on the shell 11212 (specifically, the sidewall of the shell 11212) corresponding to the second part 11215. The second sidewall portion connects laterally to the first sidewall portion. The transition point between the first and second sidewall portions corresponds to the bent part 11216. Since the first part 11214, the bent part 11216 and the second part 11215 are connected to form a bent or stepped cover 11211, it can be seen that the shape of the side wall of the shell 11212 that is in contact with the cover 11211 needs to be matched to form a bent or stepped shape, so as to realize the butt joint or abutment between the shell 11212 and the cover 11211, and thus achieve a fitting welding.

[0082] Understandably, the position where the cover 11211 is welded to the shell 11212 should be the outer periphery of the cover 11211, that is, the outer edge of the first part 11214, the second part 11215 and the bent part 11216. Understandably, the location where the first part 11214 is welded to the shell 11212 will form a first welded part 1127, which should be understood as the part where the first part 11214 and the shell 11212 are welded together; the location where the second part 11215 is welded to the shell 11212 will form a second welded part 1128, which should be understood as the part where the second part 11215 and the shell 11212 are welded together; the location where the bent part 11216 is welded to the shell 11212 will form a bent welded part 1126, which should be understood as the part where the bent part 11216 and the shell 11212 are welded together.

[0083] Since both the first part 11214 and the second part 11215 are flat, it can be understood that the fusion portion where the first part 11214 and the second part 11215 are welded to the shell 11212 is a straight-edge welding area, that is, the first welding part 1127 and the second welding part 1128 are both straight-edge welding areas, and the fusion portion where the bent part 11216 is welded to the shell 11212 is a bent welding area, that is, the bent welding part 1126 is a bent welding area.

[0084] Welding is a processing technique and joining method that uses heat, pressure, or both, with or without filler material, to achieve an atomic bond between the cover 11211 and the shell 11212. Weld penetration refers to the depth to which the base material is melted during the welding process, and it is one of the key indicators for measuring weld quality. Regarding the weld penetration depth between the cover 11211 and the shell 11212, the bent weld portion 1126 (i.e., the part where the bent portion 11216 and the shell 11212 are welded together) is defined as having a bending penetration depth L1, which should be understood as the maximum depth of the bent weld portion 1126 extending from the surface of the weld inward in the direction perpendicular to the weld surface; the first weld portion 1127 (i.e., the part where the first part 11214 and the shell 11212 are welded together) is defined as having a first penetration depth L2, which should be understood as the maximum depth of the first part 11214 extending from the surface of the weld inward in the direction perpendicular to the weld surface; the second weld portion 1128 (i.e., the part where the second part 11215 and the shell 11212 are welded together) is defined as having a second penetration depth L3, which should be understood as the maximum depth of the second part 11215 extending from the surface of the weld inward in the direction perpendicular to the weld surface.

[0085] Considering the special nature of the stress at the connection point between the bent portion 11216 and the shell 11212, in one scenario, when the weld strength at the connection point (i.e., the bent weld portion 1126) is not a bottleneck, the bending penetration depth L1 is made smaller than the first penetration depth L2, and the bending penetration depth L1 is made smaller than the second penetration depth L3. The scenario where the weld strength at the connection point (i.e., the bent weld portion 1126) is not a bottleneck includes situations where the bending weld portion... When the probability of weld failure at 1126 (i.e., the bend) is less than the probability of failure at other locations or components on the battery cell 1120, for example, the probability (or risk) of weld failure at the bend weld 1126 is less than the probability (or risk) of failure at the first part 11214 (i.e., the first weld 1127) and the second part 11215 (i.e., the second weld 1128), or for example, in a pressure test, the pressure at which weld failure at the bend weld 1126 occurs is at least greater than that at other components on the battery cell 1120 (such as... The failure pressure P2 of the explosion-proof valve 1124) is a certain safe value; another case is that when the weld strength at the connection position between the bent part 11216 and the shell 11212 (i.e., the bent weld 1126) is the bottleneck, then the bending penetration depth L1 is made greater than the first penetration depth L2, and the bending penetration depth L1 is made greater than the second penetration depth L3. Among them, the case where the weld strength at the connection position between the bent part 11216 and the shell 11212 is the bottleneck includes the probability of welding failure of the bent weld 1126 being greater than that of the battery cell 1120. When the probability (or risk) of failure is in other locations or other components, for example, the probability of welding failure of the bent weld 1126 is greater than the probability (or risk) of failure of the first part 11214 (i.e., the first weld 1127) and the second part 11215 (i.e., the second weld 1128). For example, in the gas pressure resistance test, the pressure of welding failure of the bent weld 1126 exceeds the failure pressure P2 of other components (such as the explosion-proof valve 1124) on the battery cell 1120, which is not within the scope of the safety design.

[0086] Because a greater penetration depth requires higher welding power, increasing welding current, voltage, or extending welding time are common ways to achieve this. This means the welding equipment consumes more electrical energy per unit time. In this example, when the stress in the bent section 11216 is the bottleneck, increasing the bending penetration depth L1 requires higher power input. Over long-term production, this will significantly increase electricity costs, thus raising overall production costs. Furthermore, to achieve a greater penetration depth, the welding equipment needs to operate under higher loads, which accelerates the wear of critical components such as welding electrodes and power modules. Frequent replacement of worn parts not only increases equipment maintenance costs but can also lead to production interruptions, affecting efficiency and indirectly increasing production costs. For example, under high-power welding, welding electrodes may erode more quickly and require more frequent replacement, resulting in additional economic expenditures.

[0087] Therefore, it can be seen that when the weld strength of the bent weld portion 1126 is not a bottleneck, making the bending penetration depth L1 less than the first penetration depth L2 and the bending penetration depth L1 less than the second penetration depth L3, that is, in actual production, reducing the penetration depth of the welded portion between the bent portion 11216 and the shell 11212, is beneficial to reducing production costs. When the weld strength of the bent weld portion 1126 is a bottleneck, making the bending penetration depth L1 greater than the first penetration depth L2 and the bending penetration depth L1 greater than the second penetration depth L3, that is, in actual production, increasing the penetration depth of the welded portion between the bent portion 11216 and the shell 11212, is beneficial to improving the welding quality of the bent portion 11216 and reducing the risk of welding failure of the bent portion 11216. Based on whether the weld strength (and stress condition) between the bent portion 11216 and the shell 11212 is a bottleneck, a flexible welding method is adopted to adjust the penetration depth when welding the bent portion 11216, the first part 11214, and the second part 11215 to the shell 11212, thereby finding a balance point (or balance range) between welding quality and cost optimization, improving the welding quality between the cover 11211 and the shell 11212, and optimizing the welding cost.

[0088] In this embodiment, taking into full account the special stress at the connection position between the bent portion 11216 and the shell 11212, the bending penetration depth L1 between the bent portion 11216 and the shell 11212 can be adjusted relative to the first penetration depth L2 between the first portion 11214 and the shell 11212 and the second penetration depth L3 between the second portion 11215 and the shell 11212, depending on whether the welding strength between the bent portion 11216 and the shell 11212 can become a bottleneck for welding failure. This flexible welding penetration depth design aims to find a balance point (or balance range) between welding quality and cost optimization, thereby improving the welding quality between the cover 11211 and the shell 11212 and optimizing the welding cost.

[0089] In some embodiments, refer to Figure 4-7 and Figure 9 As shown, the bending depth L1 is less than the first depth L2, and the bending depth L1 is less than the second depth L3.

[0090] Specifically, in the process of designing the penetration depth, the magnitude of the penetration depth is usually determined through pressure testing, for example, referring to... Figure 4-7 and Figure 9 As shown, the battery cell 1120 also includes an explosion-proof valve 1124 connected to the cover 11211. The explosion-proof valve 1124 has an opening pressure P1. The bent welded part 1126 (the part where the bent part 11216 is welded to the shell 11212) has a failure pressure P2. When the failure pressure P2 is greater than the opening pressure P1, and the failure pressure P2 exceeds the opening pressure P1 to a preset value P0, the bending penetration depth L1 is less than the first penetration depth L2, and the bending penetration depth L1 is less than the second penetration depth L3.

[0091] Since the explosion-proof valve 1124 is a key component for ensuring battery safety, it can open when the internal pressure of the battery cell 1120 abnormally increases due to various reasons (such as overcharging, overheating, etc.) to quickly release the internal pressure of the battery cell 1120, reducing the probability of accidents such as explosion or fire caused by excessive pressure. The failure pressure P2 of the bent welded part 1126 refers to the pressure value that the bent welded part 1126 withstands when it fails or is damaged during the gas pressure resistance test of the outer casing 1121. The opening pressure P1 of the explosion-proof valve 1124 represents the safe threshold of the internal pressure of the battery cell 1120. By comparing the failure pressure P2 of the gas-filled pressure-resistant bending welded part 1126 with the opening pressure P1 (which is also the set pressure of the explosion-proof valve 1124), the relationship between the strength of the bending part 11216 and the battery's safe pressure limit can be directly reflected. Therefore, the adjustment of the bending depth L1 is determined by comparing the opening pressure P1 of the explosion-proof valve 1124 with the failure pressure P2 of the bending welded part 1126.

[0092] Specifically, to ensure that the bent welded portion 1126 of the explosion-proof valve 1124 does not fail when it is opened, the failure pressure P2 should be at least greater than the opening pressure P1. When the failure pressure P2 exceeds the opening pressure P1 by a preset value P0, that is, during the inflation pressure test (or experiment), the failure pressure P2 of the bent welded portion 1126 is at least greater than the opening pressure P1 of the explosion-proof valve 1124 by a preset value P0. This indicates that the strength of the bent welded portion 1126 is sufficient to cope with pressure changes during use, and stress is not a key factor restricting the performance of the battery cell 1120. In other words, the weld strength of the bent welded portion 1126 is not a bottleneck or a limiting factor for the performance of the battery cell 1120. Therefore, in this case, the bending penetration depth L1 can be less than the first penetration depth L2, and the bending penetration depth L1 can be less than the second penetration depth L3. It should be noted that the starting pressure of the explosion-proof valve 1124 can be understood as the pressure at which the explosion-proof valve 1124 fails; the two expressions can be understood as having the same meaning.

[0093] In this embodiment, by reducing the penetration depth of the bent weld portion 1126, it is possible to reduce production costs while ensuring the welding strength and quality between the bent portion 11216 and the shell 11212.

[0094] In some embodiments, the bending depth L1 ranges from 0.2mm to 0.6mm; the first depth L2 ranges from 0.61mm to 1.5mm; and the second depth L3 ranges from 0.61mm to 1.5mm.

[0095] Specifically, the range of bending depth L1 is 0.2-0.6mm. It should be understood that the bending depth L1 can take any value between 0.2mm and 0.6mm. For example, L1 can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, etc.

[0096] The first penetration depth L2 is in the range of 0.61mm-1.5mm. This should be understood as meaning that the first penetration depth L2 can take any value between 0.61mm and 1.5mm. For example, L2 can be 0.61mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, etc.

[0097] The range of the second penetration depth L3 is 0.61mm-1.5mm. This should be understood as the second penetration depth L3 being any value between 0.61mm and 1.5mm. For example, L2 can be 0.61mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, etc.

[0098] It should be noted that, in one possible embodiment, the bending depth L1 ranges from 0.2 to 1.0 mm, the first penetration depth L2 ranges from 0.5 mm to 1.5 mm, and the second penetration depth L3 ranges from 0.5 mm to 1.5 mm. Within the 0.5 mm to 1.0 mm range where the bending depth L1 intersects with the first penetration depth L2 and the second penetration depth L3, the bending depth L1 should be less than the first penetration depth L2, and the bending depth L1 should be less than the second penetration depth L3. For example, when the bending depth L1 is 1.0 mm, the values ​​of the first penetration depth L2 and the second penetration depth L3 can only be between 1.1 mm and 1.5 mm.

[0099] Generally, the difference between the bending penetration depth L1 and the first penetration depth L2 or the second penetration depth L3 is usually controlled between 0.1mm and 0.5mm. This difference can be any value between 0.1mm and 0.5mm.

[0100] In this embodiment, by controlling the specific numerical ranges of the bending penetration depth L1, the first penetration depth L2, and the second penetration depth L3, it is beneficial to achieve precise control of the welding strength of the first welded part 1127, the second welded part 1128, and the bending welded part 1126, thereby improving reliability.

[0101] In some embodiments, refer to Figure 4-7 and Figure 9 As shown, the bending depth L1 is greater than the first depth L2, and the bending depth L1 is greater than the second depth L3.

[0102] Similarly, in the process of designing the melting depth, the size of the melting depth is usually determined by pressure testing. For example, the battery cell 1120 also includes an explosion-proof valve 1124 connected to the cover 11211. The explosion-proof valve 1124 has an opening pressure P1; the bent welded part 1126 has a failure pressure P2. When the failure pressure P2 is greater than the opening pressure P1 and the failure pressure P2 does not exceed the opening pressure P1 to the preset value P0, the bending melting depth L1 is greater than the first melting depth L2 and the bending melting depth L1 is greater than the second melting depth L3.

[0103] Specifically, in order to ensure that the bent welded part 1126 of the explosion-proof valve 1124 does not fail when it is opened, the failure pressure P2 should be at least greater than the opening pressure P1. When the failure pressure P2 does not exceed the opening pressure P1 to the preset value P0, that is, during the inflation pressure test (or experiment), the difference between the failure pressure P2 of the bent weld 1126 and the opening pressure P1 of the explosion-proof valve 1124 is less than the preset value P0, i.e., 0 < failure pressure P2 - opening pressure P1 < preset value P0, it indicates that the strength of the bent weld 1126 is at high risk when dealing with pressure changes during use. Stress becomes a key factor restricting the performance of the battery cell 1120. In other words, the weld strength of the bent weld 1126 becomes a bottleneck and a limiting factor for the performance of the battery cell 1120. Therefore, in this case, the bending penetration depth L1 can be greater than the first penetration depth L2 and the second penetration depth L3. Only the bending penetration depth L1 is increased, which can keep the increase in production cost within a small range and achieve the purpose of improving welding quality, which is conducive to reducing the risk of failure of the battery cell 1120 during use.

[0104] In this embodiment, by increasing the penetration depth of the bent weld portion 1126, the welding strength and quality between the bent portion 11216 and the shell 11212 can be guaranteed while keeping the increase in production costs relatively small.

[0105] In some embodiments, the bending penetration depth L1 ranges from 0.61mm to 1.5mm; the first penetration depth L2 ranges from 0.2mm to 0.6mm; and the second penetration depth L3 ranges from 0.2mm to 0.6mm.

[0106] Specifically, the bending depth L1 ranges from 0.61mm to 1.5mm. This should be understood as any value between 0.61mm and 1.5mm. For example, L1 can be 0.61mm, 0.7mm, 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, 1.5mm, etc.

[0107] The first penetration depth L2 is in the range of 0.2mm-0.6mm. It should be understood that the first penetration depth L2 can take any value between 0.2mm and 0.6mm. For example, L2 can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, etc.

[0108] The range of the second penetration depth L3 is 0.2mm-0.6mm. It should be understood that the second penetration depth L3 can take any value between 0.2mm and 0.6mm. For example, L2 can be 0.2mm, 0.3mm, 0.4mm, 0.5mm, 0.6mm, etc.

[0109] It should be noted that, in one possible embodiment, the bending depth L1 ranges from 0.61mm to 1.5mm, the first penetration depth L2 ranges from 0.2mm to 1.0mm, and the second penetration depth L3 ranges from 0.2mm to 1.0mm. Within the 0.61mm-1.0mm range where the bending depth L1 intersects with the first penetration depth L2 and the second penetration depth L3, the bending depth L1 should be greater than the first penetration depth L2, and the bending depth L1 should also be greater than the second penetration depth L3. For example, when the bending depth L1 is 0.8mm, the values ​​of the first penetration depth L2 and the second penetration depth L3 can only be between 0.61mm and 0.79mm.

[0110] Generally, the difference between the bending penetration depth L1 and the first penetration depth L2 or the second penetration depth L3 can be controlled between 0.1mm and 0.5mm. This difference can be any value between 0.1mm and 0.5mm.

[0111] In this embodiment, by controlling the specific numerical ranges of the bending penetration depth L1, the first penetration depth L2, and the second penetration depth L3, it is beneficial to achieve precise control of the welding strength of the first welded part 1127, the second welded part 1128, and the bending welded part 1126, thereby improving reliability.

[0112] In some embodiments, the preset value P0 is 0.3 MPa.

[0113] In one scenario, the difference between the failure pressure P2 and the opening pressure P1 is greater than 0.3 MPa. Specifically, failure pressure P2 - opening pressure P1 > 0.3 MPa. In other words, under the premise that failure pressure P2 is greater than opening pressure P1, failure pressure P2 is at least 0.3 MPa higher than opening pressure P1. In this case, the weld strength at the connection between the bent portion 11216 and the shell 11212 is not a bottleneck or a limiting factor for the performance of the battery cell 1120. Therefore, in this case, the bending penetration depth L1 can be less than the first penetration depth L2, and the bending penetration depth L1 can be less than the second penetration depth L3.

[0114] Another scenario is where the difference between the failure pressure P2 and the opening pressure P1 does not exceed 0.3 MPa. Specifically, 0 < failure pressure P2 - opening pressure P1 < 0.3 MPa. In other words, provided that the failure pressure P2 is greater than the opening pressure P1, the difference between the failure pressure P2 and the opening pressure P1 is less than or equal to 0.3 MPa. In this case, the weld strength at the connection between the bent portion 11216 and the shell 11212 becomes a bottleneck and a limiting factor for the performance of the battery cell 1120. Therefore, in this case, the bending penetration depth L1 can be greater than the first penetration depth L2, and the bending penetration depth L1 can be greater than the second penetration depth L3. Only the bending penetration depth L1 is increased, thereby keeping the increase in production costs within a small range and achieving the goal of improving welding quality, which is beneficial to reducing the risk of failure of the battery cell 1120 during use.

[0115] The value of 0.3 MPa is derived from extensive experimental data and practical application experience. In the early stages of performance testing and research on the battery cell 1120, technicians conducted multiple sets of experiments on the battery cell 1120 under different stress conditions, covering various operating scenarios. Analysis of the failure pressure P2 of the gas-filled pressure-resistant bending section 11216 and the opening pressure P1 of the explosion-proof valve 1124 revealed that when the difference between the failure pressure P2 and the opening pressure P1 is greater than 0.3 MPa, the strength at the bending point can adequately meet the normal operating requirements of the battery cell 1120. Even reducing the bending penetration depth L1 will not affect the weld strength, thus reducing production costs. However, when the difference between the failure pressure P2 and the opening pressure P1 is less than or equal to 0.3 MPa, the stress in the bending section 11216 significantly affects the weld strength and battery performance, requiring an increased penetration depth to ensure weld quality. Therefore, the difference between the failure pressure P2 and the opening pressure P1 is set to be greater than or equal to 0.3 MPa.

[0116] In this embodiment, the difference between the failure pressure P2 and the opening pressure P1 is greater than or equal to 0.3 MPa, thereby better achieving the goal of improving welding quality and optimizing welding costs.

[0117] In some embodiments, refer to Figure 9-11 As shown, the battery cell 1120 also includes an explosion-proof valve 1124, which is connected to the first part 11214.

[0118] Specifically, since the first part 11214 protrudes outward relative to the second part 11215 toward the side away from the electrode assembly 1122, it can be known that the volume of the accommodating cavity 11213 relative to the first part 11214 is larger. Within the accommodating cavity 11213, corresponding to the position of the first part 11214, there is more redundant space. The gas generated by the electrode assembly 1122 during charging and discharging is more likely to flow toward the space near the first part 11214 and is more likely to accumulate. Therefore, installing the explosion-proof valve 1124 on the first part 11214 is beneficial for the concentration and smooth discharge of gas.

[0119] In addition, the protruding structure makes it easier to install and disassemble the components. Installing the explosion-proof valve 1124 on the first part 11214 makes it easier to install and disassemble the explosion-proof valve 1124.

[0120] In this embodiment, the explosion-proof valve 1124 is installed on the first part 11214, which can guide the flow of gas and facilitate the gas to be discharged more concentratedly and smoothly.

[0121] In some embodiments, refer to Figure 5 As shown, the first melting depth L2 is equal to the second melting depth L3.

[0122] During welding, each change in weld penetration depth requires re-establishing a stable welding arc and molten pool. Using multiple different penetration depths necessitates setting numerous welding parameters for the welding equipment, impacting its operational stability. Furthermore, frequent parameter adjustments can lead to an unstable welding arc, causing molten pool fluctuations and welding defects such as porosity and cracks. Frequent changes in penetration depth parameters also result in unstable heat input during welding, increasing the difficulty of process control.

[0123] Therefore, in this example, by making the first penetration depth L2 equal to the second penetration depth L3, the same welding parameters can be used when welding the shell 11212 to the first part 11214 and the second part 11215. This helps reduce the decrease in work efficiency caused by setting parameters multiple times. Furthermore, having the first penetration depth L2 and the second penetration depth L3 the same also reduces the difficulty of welding and lowers the skill requirements for welders. Moreover, using the same penetration depth between the first part 11214 and the second part 11215 and the shell 11212 improves the consistency of the welding between the cover 11211 and the shell 11212, which helps reduce the probability of uneven stress distribution.

[0124] In this embodiment, the first part 11214 and the second part 11215 both use the same welding penetration depth with the shell 11212, which helps to improve the welding quality, reduce the welding difficulty, and improve the consistency of welding between the cover 11211 and the shell 11212.

[0125] In some embodiments, refer to Figure 10 , Figure 12 and Figure 13 As shown, the battery cell 1120 also includes an adapter 1129 and an electrode terminal 1123. The electrode terminal 1123 is disposed in the second part 11215. The electrode assembly 1122 has a tab 1125 disposed opposite to the first part 11214. The tab 1125 is connected to the electrode terminal 1123 through the adapter 1129. The first part 11214 protrudes relative to the second part 11215 along the first direction X. A third welded part 1130 is formed between the tab 1125 and the adapter 1129. In the second direction Y, the third welded part 1130 has at least a portion opposite to the bent part 11216. The second direction Y is perpendicular to the first direction X.

[0126] Specifically, the tab 1125 is a structure that electrically connects the electrode assembly 1122 to the electrode terminal 1123. The tab 1125 generally includes a positive tab 1125 and a negative tab 1125. The tab 1125 can be directly electrically connected to the electrode terminal 1123, or the tab 1125 can also be electrically connected to the electrode terminal 1123 through an adapter.

[0127] Since the first part 11214 protrudes outward relative to the second part 11215 toward the electrode assembly 1122, a large redundant space is formed in the accommodating cavity 11213 corresponding to the position of the first part 11214, which can accommodate the tab 1125. The space in the accommodating cavity 11213 for accommodating the body of the electrode assembly 1122 will be increased, which is beneficial to increasing the volume of the body of the electrode assembly 1122, and thus beneficial to improving the energy density of the battery cell 1120.

[0128] For example, the electrode assembly 1122 is electrically connected to the electrode terminal 1123 via the adapter 1129. The electrode assembly 1122 has tabs 1125 formed on it, which are connected and fixed to the adapter 1129, thereby achieving electrical connection between the tabs 1125 and the adapter 1129. The connection between the tabs 1125 and the adapter 1129 is achieved by welding. Therefore, a welded fusion portion is formed between the tabs 1125 and the adapter 1129. This welded fusion portion is defined as the third weld portion 1130, which visually forms a solder mark.

[0129] Electrode terminals 1123 are an important component of the battery cell 1120, primarily used to achieve electrical connection between the internal electrode assembly 1122 and external circuitry. Electrode terminals 1123 are typically made of metallic materials, such as copper, aluminum, and their alloys, possessing good conductivity. The shape of electrode terminals 1123 is generally cylindrical or prismatic. One end of the electrode terminal 1123 extends into the housing 1121 and is electrically connected to the adapter component 1129, while the other end extends out of the housing 1121 of the battery cell 1120 for connecting to external circuitry. Externally, electrode terminals 1123 typically have threads, slots, or terminals to facilitate connection to external wires or other electrical equipment.

[0130] Electrode terminals 1123 serve as channels for the input and output of electrical energy in battery cell 1120. During discharge, the current generated within battery cell 1120 is conducted to the external circuit, providing electrical energy to the device. During charging, current from an external power source is introduced into battery cell 1120, allowing it to store electrical energy. Electrode terminals 1123 typically include a positive electrode terminal and a negative electrode terminal.

[0131] In this design, the height direction of the battery cell 1120 is the first direction X, the length direction of the battery cell 1120 is the second direction Y, and the width direction of the battery cell 1120 is the third direction. Regarding the relative positions of the electrode terminals 1123 and the tabs 1125, they are spaced apart in the second direction Y. The second direction Y can be understood as the length direction of the battery cell 1120, meaning it is perpendicular to the height direction. Therefore, it can be understood that the electrode terminals 1123 and the tabs 1125 are spaced apart in a direction perpendicular to the height. For example, when the battery cell 1120 is placed vertically, the height direction is the vertical direction, and the second direction Y can be understood as the horizontal direction.

[0132] The function of the adapter 1129 is to connect the tab 1125 and the electrode terminal 1123 respectively, so that the tab 1125 and the electrode terminal 1123 are electrically connected and conductive. The adapter 1129 is generally made of a conductive metal material, such as copper, aluminum, nickel, or composite materials, which have high electrical and thermal conductivity.

[0133] Since the adapter 1129 is used to connect the tab 1125 and the electrode terminal 1123, it is known that the adapter 1129 has portions that are respectively opposite to the first portion 11214, the second portion 11215 and the bent portion 11216. Furthermore, the shape of each portion of the adapter 1129 matches the shape of the first portion 11214, the second portion 11215 and the bent portion 11216, thereby making the adapter 1129 form a bent or stepped shape that matches the corresponding portion of the cover 11211.

[0134] In the second direction Y, the third welded portion 1130 has at least a portion opposite to the bent portion 11216. Specifically, it forms a projection surface in the second direction Y, that is, a projection surface perpendicular to the first direction X, so that both the third welded portion 1130 and the bent portion 11216 are projected onto the projection surface. (Refer to...) Figure 13 As shown, the projected height of the third welded portion 1130 is H2, and the projected height of the bent portion 11216 is H1. Therefore, on the projection plane, the third welded portion 1130 and the bent portion 11216 have overlapping projected areas. Of course, this includes the following cases: first, the projected area of ​​the third welded portion 1130 is equal to the projected area of ​​the bent portion 11216; second, the projected area of ​​the third welded portion 1130 is greater than the projected area of ​​the bent portion 11216; and third, the projected area of ​​the third welded portion 1130 is less than the projected area of ​​the bent portion 11216.

[0135] The third welding portion 1130 and the bending portion 11216 form overlapping projected areas in the second direction Y, causing the position of the tab 1125 to move away from the electrode assembly 1122 (i.e., closer to the first portion 11214). Thus, the tab 1125 and the electrode terminal 1123 form overlapping areas in the second direction Y, allowing the space corresponding to the bending portion 11216 in the second direction Y (or the protruding space below the first portion 11214) to accommodate the tab 1125. This helps to increase the volume of the main body of the electrode assembly 1122, save space, and improve space utilization, thereby improving the energy density of the battery cell 1120.

[0136] In this embodiment, by making the third welding portion 1130 and the bending portion 11216 form overlapping projected areas in the second direction Y, it is beneficial to increase the volume of the electrode assembly 1122, thereby improving the energy density of the battery cell 1120.

[0137] In some embodiments, refer to Figure 3 and Figure 8As shown, the bending portion 11216 includes a first bending portion 11217, a straight portion 11219, and a second bending portion 11218. The straight portion 11219 is connected between the first bending portion 11217 and the second bending portion 11218. The first bending portion 11217 is connected to the first part 11214, and the second bending portion 11218 is connected to the second part 11215. The portion of the first bending portion 11217 that is welded to the shell 11212 has a first sub-weld depth. The portion of the second bending portion 11218 that is welded to the shell 11212 has a second sub-weld depth. The portion of the straight portion 11219 that is welded to the shell 11212 has a third sub-weld depth. Both the first sub-weld depth and the second sub-weld depth are greater than the third sub-weld depth.

[0138] Specifically, the bent portion 11216 has a certain extension length. A first curved portion 11217 is formed at the position where it connects with the first portion 11214. The first curved portion 11217 constitutes the transition portion connecting the bent portion 11216 and the first portion 11214. The extension trajectory of the first curved portion 11217 is an arc. For example, the first curved portion 11217 is an arc-shaped plate. Similarly, a second curved portion 11218 is formed at the position where it connects with the second portion 11215. The second curved portion 11218 constitutes the transition portion connecting the bent portion 11216 and the second portion 11215. The extension trajectory of the second curved portion 11218 is an arc. For example, the second curved portion 11218 is an arc-shaped plate. The straight portion 11219 is connected between the first curved portion 11217 and the second curved portion 11218. The extension trajectory of the straight portion 11219 is straight, for example, the straight portion 11219 is a flat plate.

[0139] During use, compared to the straight portion 11219, the first curved portion 11217 and the second curved portion 11218 of the battery device 1100 bear greater stress. A relatively deeper weld penetration allows for a more secure connection between the housing 11212 and the cover 11211 at the first curved portion 11217 and the second curved portion 11218, thus enhancing the load-bearing capacity of the weld. For example, when the battery device 1100 is subjected to external forces such as vibration or impact, the deeper weld penetration can effectively disperse stress, reducing the risk of weld cracking due to stress concentration, thereby improving the overall structural stability of the battery device 1100 and extending its service life.

[0140] In this embodiment, increasing the weld penetration between the first bent portion 11217 and the second bent portion 11218 and the shell 11212 respectively helps to disperse stress, improve welding strength, and reduce the risk of weld cracking.

[0141] In some embodiments, the first sub-melting depth is equal to the second sub-melting depth.

[0142] It is known that during welding, each change in the weld penetration depth requires re-establishing a stable welding arc and molten pool. Using multiple different penetration depths necessitates setting numerous welding parameters for the welding equipment, impacting its operational stability. Furthermore, frequent parameter adjustments can lead to an unstable welding arc, causing molten pool fluctuations and welding defects such as porosity and cracks. Frequent changes in penetration depth parameters also result in unstable heat input during welding, increasing the difficulty of process control.

[0143] Therefore, in this example, by making the first sub-penetration depth equal to the second sub-penetration depth, the same welding parameters can be used when welding the shell 11212 to the first curved portion 11217 and the second curved portion 11218. This helps reduce the decrease in work efficiency caused by setting parameters multiple times. Furthermore, having the first and second sub-penetration depths equal also reduces the difficulty of welding and lowers the skill requirements for welders. Moreover, using the same penetration depth between the first curved portion 11217 and the second curved portion 11218 and the shell 11212 improves the consistency of the welding between the outer shell 1121 and the shell 11212, helping to reduce the probability of uneven stress distribution.

[0144] In this embodiment, the first part 11214 and the second part 11215 both have the same welding penetration depth with the shell 11212, which helps to improve the welding quality, reduce the welding difficulty, and improve the consistency of welding between the bent part 11216 and the shell 11212.

[0145] In some embodiments, refer to Figure 4-7 As shown, the side edge of the cover 11211 extends to the outer side of the housing 11212 so that the housing 11212 is welded to the cover 11211 on the outer side.

[0146] Specifically, taking a cover 11211 that is plate-shaped and a housing 11212 that has an opening as an example, the cover 11211 is placed over the opening side of the housing 11212 and is welded to the housing 11212 for fixation. The part of the cover 11211 away from the center and near the edge is called the side edge. The housing 11212 has an outer surface. Taking a square battery device 1100 as an example, the surface direction of the cover 11211 can be perpendicular to the outer surface of the housing 11212.

[0147] If the side edge of the cover 11211 extends to the outer side of the shell 11212, then it can be seen that the welding position between the cover 11211 and the shell 11212 is located on the outer side. That is to say, the welding position between the cover 11211 and the shell 11212 is located on the outer side of the shell 11212, and the weld is located at the position where the top of the shell 11212 contacts the cover 11211, and is arranged around the circumference of the cover 11211.

[0148] Since the explosion-proof valve 1124 is located on the cover 11211 and the battery device 1100 is placed upright, the gas generated during the charging and discharging of the battery device 1100 will converge toward the cover 11211. Setting the welding position between the cover 11211 and the housing 11212 on the side helps to avoid the impact pressure of the gas at the welding position, reduces the damage to the weld caused by the gas pressure, and protects the weld.

[0149] In this embodiment, the position where the cover 11211 is welded to the housing 11212 is located on the side of the housing 11212, so that the welding equipment can be located on the side of the housing 11212, which protects the welding position and improves the convenience of welding.

[0150] In some embodiments, the housing 11212 is connected to the side edge of the cover 11211 and extends to the top surface of the cover 11211, so that the housing 11212 is welded to the cover 11211 at the top.

[0151] Specifically, relative to the outer side of the housing 11212, the outer shell 1121 also has a top surface. The top surface of the outer shell 1121 is the top surface of the cover 11211. When the cover 11211 is placed on the opening side of the housing 11212, the wall of the opening position of the housing 11212 extends to the side edge of the cover 11211 and extends to the top surface of the cover 11211, so that the welding position between the cover 11211 and the housing 11212 is located on the top surface of the cover 11211. That is to say, the weld position between the cover 11211 and the housing 11212 is arranged around the top surface of the cover 11211, and the cover 11211 and the housing 11212 are welded together by the top surface welding method.

[0152] In this embodiment, the cover 11211 and the shell 11212 are welded at the top, which helps to improve the enclosure of the cover 11212 by the shell 11212 and improves the welding strength between the shell 11212 and the cover 11211.

[0153] In some embodiments, refer to Figure 3 , Figure 10 and Figure 11As shown, there are two second parts 11215, and the first part 11214 is connected between the two second parts 11215. Each second part 11215 is connected to the first part 11214 at a position where a bend 11216 is formed.

[0154] Specifically, for the cover 11211, a first portion 11214 protrudes from the cover 11211, thereby forming a convex battery cell 1120. Regarding the position of the first portion 11214 on the cover 11211, it is generally located in the middle of the cover 11211. Therefore, two second portions 11215 are provided, with the first portion 11214 connected between the two second portions 11215. The first portion 11214 protrudes outward relative to the two second portions 11215 in a direction away from the electrode assembly 1122. The two second portions 11215 can be arranged symmetrically about the first portion 11214.

[0155] Each of the second parts 11215 and the first part 11214 forms a bend 11216, indicating that there are two bend welding positions between one side of the cover 11211 and the shell 11212. The two bends 11216 can be arranged symmetrically.

[0156] The protrusion height of the first part 11214 relative to the second part 11215 can be 0.5 to 5 times the thickness of the cover 11211, or, when the electrode terminal 1123 is connected to the second part 11215, the outer surface of the first part 11214 can be flush with the top surface of the electrode terminal 1123.

[0157] In this embodiment, by setting two second parts 11215, the first part 11214 can be located in the middle of the cover 11211. The explosion-proof valve 1124 can be connected to the middle of the first part 11214. The gas generated by the electrode assembly 1122 can converge symmetrically to the explosion-proof valve 1124, which facilitates the smooth discharge of gas.

[0158] In some embodiments, refer to Figure 3 and Figure 9-11 As shown, the battery cell 1120 also includes an electrode terminal 1123, which is connected to the second part 11215.

[0159] Specifically, electrode terminal 1123 can also be understood as a pole post. Electrode terminal 1123 may include a positive electrode terminal 1123 and a negative electrode terminal 1123. Electrode terminal 1123 can be electrically connected to the tab 1125 of electrode assembly 1122, thereby enabling electrode assembly 1122 to be connected to external circuit through electrode terminal 1123.

[0160] The second part 11215 has two components, meaning that one electrode terminal 1123 can be connected to each second part 11215. The top of the electrode terminal 1123 protrudes from the top surface (upper surface or outer surface) of the second part 11215. That is, the electrode terminal 1123 protrudes from the side of the second part 11215 opposite to the electrode assembly 1122 by a certain height. This protrusion height can be equal to the height of the second part 11215 protruding from the second part 11215, so that the top surface of the electrode terminal 1123 is flush with the top surface (upper surface or outer surface) of the first part 11214. This allows the first part 11214 to fully utilize the space on both sides of the protruding portion of the electrode terminal 1123, improving the space utilization rate of the battery cell 1120.

[0161] In this embodiment, the electrode terminal 1123 is connected to the second part 11215, so that the first part 11214 can make full use of the space on both sides of the protruding portion of the electrode terminal 1123, thereby improving the space utilization rate of the battery cell 1120.

[0162] In one specific embodiment, refer to Figure 3-11As shown, the battery cell 1120 includes a housing 11212, a cover 11211, and an electrode assembly 1122. The cover 11211 is connected to the housing 11212 and together with the housing 11212 forms a receiving cavity 11213. The cover 11211 includes a first part 11214, a second part 11215, and a bent part 11216. The first part 11214 protrudes relative to the second part 11215 in a direction away from the receiving cavity 11213. The bent part 11216 connects the first part 11214 and the second part 11215. The electrode assembly 1122 is housed within the receiving cavity 11213. The first part... The first part 11214, the second part 11215, and the bent part 11216 are all welded to the shell 11212, forming the first welded part 1127, the second welded part 1128, and the bent welded part 1126, respectively. The bent welded part 1126 has a bending penetration depth L1, the first welded part 1127 has a first penetration depth L2, and the second welded part 1128 has a second penetration depth L3. The bending penetration depth L1 is greater than or less than the first penetration depth L2, and the bending penetration depth L1 is greater than or less than the second penetration depth L3; wherein, the bending penetration depth L1 is less than the first penetration depth L2, and the bending penetration depth L1 is less than the second penetration depth L3, for example, the range of the bending penetration depth L1 is 0.2. The first melting depth L2 ranges from 0.61mm to 1.5mm; the second melting depth L3 ranges from 0.61mm to 1.5mm; or, the bending melting depth L1 is greater than the first melting depth L2 and the bending melting depth L1 is greater than the second melting depth L3, for example, the bending melting depth L1 ranges from 0.61mm to 1.5mm; the first melting depth L2 ranges from 0.2mm to 0.6mm; the second melting depth L3 ranges from 0.2mm to 0.6mm; the side edge of the cover 11211 extends to the outer side of the shell 11212 so that the shell 11212 is welded to the cover 11211 on the outer side; battery cell 1 120 also includes an adapter 1129 and an electrode terminal 1123. The electrode terminal 1123 is disposed in the second part 11215. The electrode assembly 1122 has a tab 1125 disposed opposite to the first part 11214. The tab 1125 is connected to the electrode terminal 1123 via the adapter 1129. The first part 11214 protrudes relative to the second part 11215 along a first direction X. A third weld portion 1130 is formed between the tab 1125 and the adapter 1129. In the second direction Y, the third weld portion 1130 has at least a portion opposite to the bent portion 11216. The second direction Y is perpendicular to the first direction X.

[0163] According to some embodiments of this application, refer to Figure 2As shown, this application also provides a battery device 1100, which includes a battery cell 1120 as described in any of the above embodiments. The battery device 1100 disclosed in the embodiments of this application can be used in electrical devices that use the battery device 1100 as a power source or in various energy storage devices and energy storage systems that use the battery device 1100 as an energy storage element.

[0164] The battery apparatus 1100 may include one or more battery cells for providing voltage and capacity. The battery cell assembly may include multiple battery cells 1120, which are connected in series, parallel, or mixed connections via a busbar.

[0165] The battery device 1100 can be a battery pack, which generally includes a housing 1110 and one or more individual battery cells housed in the housing 1110.

[0166] The battery assembly 1100 may further include a housing 1110, with each battery cell 1120 housed within a receiving space 1113 within the housing 1110. For the housing 1110, see reference... Figure 2 As shown, the housing 1110 is used to accommodate the battery cell 1120. Therefore, the housing 1110 may include a first housing portion 1111 and a second housing portion 1112. The first housing portion 1111 and the second housing portion 1112 cover each other, and the first housing portion 1111 and the second housing portion 1112 together define an accommodating space 1113 for accommodating the battery cell 1120. The second housing portion 1112 may be a hollow structure with one end open, and the first housing portion 1111 may be a plate-like structure. The first housing portion 1111 covers the open side of the second housing portion 1112, so that the first housing portion 1111 and the second housing portion 1112 together define the accommodating space 1113. Alternatively, the first housing portion 1111 and the second housing portion 1112 may both be hollow structures with one side open, and the open side of the first housing portion 1111 covers the open side of the second housing portion 1112. Of course, the box 1110 formed by the first box 1111 and the second box 1112 can be of various shapes, such as a cylinder, a cuboid, etc.

[0167] According to some embodiments of this application, this application also provides an energy storage device, which includes a plurality of battery cells 1120 as described in the above embodiments or a plurality of battery devices 1100 as described in the above embodiments, wherein the battery cells 1120 and the battery devices 1100 are used to store or provide electrical energy.

[0168] Specifically, an energy storage device may include one or more battery clusters to increase the voltage and capacity of the energy storage device. A battery cluster may include multiple individual battery cells 1120 or multiple battery devices 1100, which are connected in series via a busbar to increase the voltage of the energy storage device. When the energy storage device includes multiple battery clusters, the multiple battery clusters are connected in parallel to increase the capacity of the energy storage device.

[0169] Energy storage devices can be used in energy storage power stations, wind power generation systems, solar power generation systems, mobile power systems, or temporary power supply systems. Energy storage devices can store electrical energy as needed and output it when appropriate. For example, an energy storage device can store electrical energy during off-peak hours and provide power to relevant users or electrical equipment during peak hours. The energy storage system provided in this application embodiment can be any power system that requires energy storage devices.

[0170] In some embodiments, the energy storage device is an energy storage container or an energy storage cabinet.

[0171] In some embodiments, the energy storage device may include a cabinet and one or more battery clusters housed within the cabinet.

[0172] In some embodiments, the energy storage device may include modules such as a thermal management module, a main control module, a central control module, a power distribution module, and a fire protection module.

[0173] As an example, the thermal management module may include a liquid cooling unit that supplies coolant to each battery device 1100 via piping to regulate the temperature of the individual battery cells 1120.

[0174] As an example, the main control module can serve as the battery management unit for the battery cluster, used to monitor and manage the battery cluster. The main control module can monitor information such as the current, voltage, power, or temperature of the battery cluster. For instance, it can control the charging and discharging current and voltage of the battery cluster. The main control module includes modules such as an auxiliary battery management unit (SBMU) and a fusion switch.

[0175] As an example, the central control module can serve as the battery management unit for an energy storage device, used to monitor and manage the device. The central control module can monitor information such as the energy storage device's current, voltage, power, state of charge, or temperature. For instance, it can control the charging and discharging current and voltage of the energy storage device. As an example, the central control module includes modules such as an Insulation Monitoring Module (IMM), a Master Battery Management Unit (MBMU), an Ethernet (ETH) module, and a fiber optic conversion module.

[0176] As an example, the fire protection module includes a control panel, detectors, alarm devices, etc., used to detect, alarm, or extinguish fires in the energy storage system.

[0177] As an example, a power distribution module can be used to distribute power to modules in an energy storage device that require electricity.

[0178] According to some embodiments of this application, this application also provides an energy storage system, which includes a power conversion device and an energy storage device as described in the above embodiments. The power conversion device is used to electrically connect the power generation device and the energy storage device.

[0179] In some embodiments, the energy storage system may include one or more energy storage devices and a power conversion system (PCS), wherein the power conversion system is used to connect the power generation device and the energy storage device. The power generation device generates electrical energy, which can be stored in the energy storage device through the power conversion system. As examples, the power generation device may specifically be a solar panel, hydroelectric power generation device, thermal power generation device, wind power generation device, etc. The specific type of power generation device is not limited in this application.

[0180] According to some embodiments of this application, refer to Figure 1 As shown, this application also provides an electrical device, which includes the battery cell 1120, the battery device 1100, the energy storage device, or the energy storage system described in the above embodiments. The battery cell 1120 and the battery device 1100 are used to store or provide electrical energy. The electrical device can be, but is not limited to, mobile phones, portable devices, laptops, electric toys, power tools, electric vehicles, vehicles 1000, ships, spacecraft, etc. Among them, electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric boat toys, and electric airplane toys, etc., and spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0181] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0182] Please refer to Figure 1 As shown, Figure 1 This is a schematic diagram of the structure of a vehicle 1000 provided in some embodiments of this application. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 1100 is provided inside the vehicle 1000, and the battery device 1100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 1100 can be used to power the vehicle 1000; for example, the battery device 1100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 1200 and a motor 1300. The controller 1200 is used to control the battery device 1100 to supply power to the motor 1300, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0183] In some embodiments of this application, the battery device 1100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0184] The technical solutions described in the embodiments of this application are applicable to various electrical devices that use battery cells 1120, such as mobile phones, portable devices, laptops, electric vehicles, electric toys, power tools, vehicles 1000, ships and spacecraft, etc. For example, spacecraft include airplanes, rockets, space shuttles and spacecraft.

[0185] The examples of electrical devices in this application are based on the examples of the battery cell 1120 and battery device 1100 described above. The examples of electrical devices include all the technical effects of the examples of the battery cell 1120 and battery device 1100 described above, and will not be repeated here.

[0186] According to some embodiments of this application, this application also provides a charging network, which includes charging piles and energy storage devices or energy storage systems as described in the above embodiments, wherein the energy storage devices are used to provide electrical energy to the charging piles.

[0187] For example, the charging network includes charging stations and energy storage devices. The charging stations are electrically connected to the energy storage devices, which provide power to the charging stations. The charging stations are also electrically connected to a battery unit 1100 in the energy storage devices via cables. The battery unit 1100 can provide its stored electrical energy to the charging stations. The charging stations have one or more connectors for connecting to electrical devices (such as vehicle 1000) to replenish their power.

[0188] Energy storage devices can be located inside the charging pile (e.g., an integrated energy storage and charging unit) or outside the charging pile.

[0189] The above are merely preferred embodiments of this application, and only specifically describe the technical principles of this application. These descriptions are only for explaining the principles of this application and should not be construed as limiting the scope of protection of this application in any way. Based on this explanation, any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application, as well as other specific embodiments of this application that can be conceived by those skilled in the art without creative effort, should be included within the scope of protection of this application.

Claims

1. A battery cell (1120), characterized in that, include: Casing (11212); A cover (11211) is connected to the housing (11212) and together with the housing (11212) forms a receiving cavity (11213); the cover (11211) includes a first part (11214), a second part (11215) and a bent part (11216), the first part (11214) protrudes relative to the second part (11215) in a direction away from the receiving cavity (11213), and the bent part (11216) connects the first part (11214) and the second part (11215). The electrode assembly (1122) is housed within the accommodating cavity (11213); The first part (11214), the second part (11215), and the bent part (11216) are all welded to the shell (11212) and respectively form a first welded part (1127), a second welded part (1128), and a bent welded part (1126). The bent welded part (1126) has a bending penetration depth (L1), the first welded part (1127) has a first penetration depth (L2), and the second welded part (1128) has a second penetration depth (L3). The bending penetration depth (L1) is greater than or less than the first penetration depth (L2), and the bending penetration depth (L1) is greater than or less than the second penetration depth (L3).

2. The battery cell (1120) as described in claim 1, characterized in that, The bending depth (L1) is less than the first depth (L2), and the bending depth (L1) is less than the second depth (L3).

3. The battery cell (1120) as described in claim 2, characterized in that, The bending depth (L1) ranges from 0.2mm to 0.6mm; the first depth (L2) ranges from 0.61mm to 1.5mm; the first depth (L2) ranges from 0.61mm to 1.5mm.

4. The battery cell (1120) as described in claim 1, characterized in that, The bending depth (L1) is greater than the first depth (L2), and the bending depth (L1) is greater than the second depth (L3).

5. The battery cell (1120) as described in claim 4, characterized in that, The bending depth (L1) ranges from 0.61mm to 1.5mm; the first depth (L2) ranges from 0.2mm to 0.6mm; and the second depth (L3) ranges from 0.2mm to 0.6mm.

6. The battery cell (1120) as described in claim 1, characterized in that, The first melting depth (L2) is equal to the second melting depth (L3).

7. The battery cell (1120) according to any one of claims 1-6, characterized in that, The battery cell (1120) further includes an adapter (1129) and an electrode terminal (1123). The electrode terminal (1123) is disposed in the second part (11215). The electrode assembly (1122) has a tab (1125) disposed opposite to the first part (11214). The tab (1125) is connected to the electrode terminal (1123) through the adapter (1129). The first part (11214) protrudes in a first direction (X) relative to the second part (11215). A third weld (1130) is formed between the tab (1125) and the adapter (1129). In a second direction (Y), the third weld (1130) is at least partially opposite to the bent part (11216). The second direction (Y) is perpendicular to the first direction (X).

8. The battery cell (1120) according to any one of claims 1-6, characterized in that, The bending portion (11216) includes a first bending portion (11217), a straight portion (11219), and a second bending portion (11218). The straight portion (11219) is connected between the first bending portion (11217) and the second bending portion (11218). The first bending portion (11217) is connected to the first part (11214), and the second bending portion (11218) is connected to the second part (11215). The portion of the first curved portion (11217) that is welded to the shell (11212) has a first sub-melt depth, the portion of the second curved portion (11218) that is welded to the shell (11212) has a second sub-melt depth, and the portion of the straight portion (11219) that is welded to the shell (11212) has a third sub-melt depth. The first sub-melt depth and the second sub-melt depth are both greater than the third sub-melt depth.

9. The battery cell (1120) as described in claim 8, characterized in that, The first sub-melting depth is equal to the second sub-melting depth.

10. The battery cell (1120) according to any one of claims 1-6, characterized in that, The side edge of the cover (11211) extends to the outer side of the housing (11212) so that the housing (11212) is welded to the cover (11211) on the outer side.

11. The battery cell (1120) according to any one of claims 1-6, characterized in that, The housing (11212) is connected to the side edge of the cover (11211) and extends to the top surface of the cover (11211) so that the housing (11212) is welded to the cover (11211) at the top.

12. The battery cell (1120) according to any one of claims 1-6, characterized in that, The second part (11215) is provided in two parts, and the first part (11214) is connected between the two second parts (11215). The bending part (11216) is formed at the position where each second part (11215) is connected to the first part (11214).

13. A battery device (1100), characterized in that, The battery device (1100) includes a battery cell (1120) as described in any one of claims 1-12.

14. An electrical appliance, characterized in that, The electrical device includes a battery cell (1120) as described in any one of claims 1-12; or, The electrical device includes the battery device (1100) as described in claim 13, the battery device (1100) being used to store or provide electrical energy.

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