Battery monomer, battery and electric device

Abstract

The invention belongs to the technical field of batteries, and particularly relates to a single battery, a battery and a power utilization device, the single battery comprises: a shell having an accommodating cavity; the top cover is used for buckling the opening of the shell; the battery cell is accommodated in the accommodating cavity, and a tab is arranged at one end, facing the top cover, of the battery cell; the current collecting plate is accommodated in the accommodating cavity and is positioned between a tab of the battery cell and the top cover, and the current collecting plate is provided with a first area and a second area arranged around the first area; wherein the second area protrudes towards the opening relative to the first area, so that a boss is formed on the side, facing the opening, of the flow collecting disc, the boss is located between the shell and the top cover, the boss and the shell are welded to form a first welding part, and the first welding part is located on the side, facing the opening, of the flow collecting disc. The boss and the top cover are welded to form a second welding part, and the first area is electrically connected with the tab; the welding stress is effectively dispersed, and the welding difficulty is reduced.

Description

Technical Field

[0001] The present invention belongs to the technical field of batteries, and in particular relates to a battery cell, a battery and an electrical device. Background Art

[0002] The welding process is particularly important in the battery manufacturing process. The welding process is not only the key to ensure the stability of the battery structure, but also an important guarantee for battery performance and safety.

[0003] In the prior art, the battery cell is generally sealed by side welding. That is, the cover plate is placed on the opening of the shell, and then the shell and the cover plate are welded from the outside of the shell side wall. During the welding process, the clamp or welding head holding the battery cell usually needs to be rotated around the shell to complete the welding process of the entire side wall. This results in low welding efficiency of the side welding process.

[0004] In order to improve the welding efficiency of battery cells, the sealing of battery cells adopts the top welding process. That is, the purpose of sealing the battery cells is achieved by welding directly on the top contact surface between the top cover and the shell. During the welding process, the welding head does not need to rotate around the shell, but only needs to perform welding operations on the plane where the top cover and the shell contact, which greatly improves the welding efficiency.

[0005] However, in actual operation, the top cover usually needs to be welded to the collecting plate and the shell separately. This step is not only complicated but also time-consuming, which significantly reduces the efficiency of the entire welding process. Summary of the invention

[0006] The purpose of the present invention is to provide a battery cell, a battery and an electrical device to address the deficiencies of the prior art, and solve the technical problem of the high welding difficulty faced when welding the top cover to the collecting plate and the shell separately in the prior art.

[0007] In order to achieve the above object, the present invention adopts the following technical solutions:

[0008] In a first aspect, the present invention provides a battery cell, comprising:

[0009] A shell having a receiving cavity;

[0010] A top cover, snap-fitted to the opening of the shell;

[0011] A battery cell is accommodated in the accommodation cavity, and a pole ear is provided at one end of the battery cell facing the top cover; and

[0012] A current collecting plate, received in the receiving cavity and located between the pole ear of the battery cell and the top cover, wherein the current collecting plate has a first area and a second area arranged around the first area;

[0013] Among them, the second area is protruded toward the opening relative to the first area to form a boss on the side of the collecting plate facing the opening, the boss is located between the shell and the top cover, the boss and the shell are welded to form a first welding part, the boss and the top cover are welded to form a second welding part, the first welding part and the second welding part are spaced apart, and the first area is electrically connected to the pole ear.

[0014] In some embodiments, the boss includes a first metal layer, the first metal layer and the shell are welded to form the first welding portion, and the first metal layer and the top cover are welded to form the second welding portion;

[0015] Wherein, the first metal layer and the shell are made of the same material;

[0016] And / or, the first metal layer and the top cover are made of the same material.

[0017] In some embodiments, along the height direction of the battery core, the boss further includes a second metal layer stacked with the first metal layer, and the second metal layer is made of a different material from the first metal layer.

[0018] In some embodiments, the first metal layer is aluminum and the second metal layer is copper.

[0019] In some embodiments, a distance L5 between a surface of the top cover facing the battery cell and the battery cell is smaller than a distance L6 between a bonding surface of the first metal layer and the second metal layer and the battery cell.

[0020] In some embodiments, an extension direction of the first welding portion is the same as an extension direction of the second welding portion, and the extension direction is a height direction of the battery core.

[0021] In some embodiments, a distance L3 between an inner edge of the first welding portion and an outer edge of the second welding portion satisfies the relationship: L3 ≥ 3 mm, wherein in a radial direction, both the first welding portion and the second welding portion have an outer side and an inner side that is closer to the center hole of the battery cell relative to the outer side.

[0022] In some embodiments, the outer edge of the boss forms a first step, the inner wall of the shell forms a second step, the first step and the second step are spliced ​​into a first groove, and the first welding portion is formed in the first groove;

[0023] And / or, the inner edge of the boss forms a third step, the outer wall of the top cover forms a fourth step, the third step and the fourth step are spliced ​​into a second groove, and the second welding portion is formed in the second groove.

[0024] In some embodiments, along the radial direction, the width L1 of the first groove satisfies the relationship: L1 ≥ 0.5 mm;

[0025] And / or, the width L2 of the second groove satisfies the relationship: L2 ≥ 0.5 mm.

[0026] In some embodiments, the depth of the first groove is 0.4 to 0.6 mm;

[0027] And / or, the depth of the second groove is 0.4-0.6 mm.

[0028] In some embodiments, a fifth step is formed on the inner side of the boss, the top cover is mounted on the fifth step, and a side of the top cover facing away from the battery cell is flush with an end face of the boss.

[0029] In some embodiments, the second region forms a third groove corresponding to the boss on a side of the collecting plate away from the opening, and a distance L7 between a bottom wall of the third groove and the battery cell is smaller than a distance L8 between a step surface of the fifth step and the battery cell.

[0030] In some embodiments, a weak area is provided on the top cover, and a distance L4 between an outer edge of the weak area and an inner edge of the second welding portion satisfies the relationship: L4 ≥ 4 mm, wherein in the radial direction, the weak area and the second welding portion both have an outer side and an inner side closer to the center hole of the battery cell relative to the outer side.

[0031] In a second aspect, the present invention provides a battery, comprising the battery cell of the above embodiment.

[0032] In a third aspect, the present invention provides an electrical device, including the battery cell of the above embodiment;

[0033] Or, the battery of the above embodiment.

[0034] Compared with the prior art, the present invention has the following beneficial effects:

[0035] The battery cell of the present invention is used in conjunction with a shell, a top cover, a battery cell and a current collecting plate. The top cover is buckled with the opening of the shell, and the battery cell and the current collecting plate are both contained in the containing cavity of the shell. The current collecting plate is located between the top cover and the pole lug of the battery cell, which effectively ensures the structural stability of the battery cell. The first area of ​​the current collecting plate and the second area arranged around the first area, the first area is used to electrically connect with the pole lug of the battery cell, and the second area is used to electrically connect with the shell and the top cover, which effectively optimizes the current transmission path of the battery cell and improves the performance of the battery cell. Through the setting of the boss, the boss is located between the shell and the top cover, the boss and the shell are welded to form a first welding part, the boss and the top cover are welded to form a second welding part, and the first welding part and the second welding part are arranged at intervals, which effectively disperses the welding stress and reduces the risk of welding failure. In addition, when the boss is welded to the shell and the boss is welded to the top cover, only two components are involved. Compared with welding three components at the same time, the welding process is more controllable, the welding difficulty is reduced, and the welding quality is improved.

[0036] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0038] Figure 1 It is a schematic diagram of the structure of a battery cell of the present invention.

[0039] Figure 2 It is a cross-sectional view of a battery cell of the present invention.

[0040] Figure 3 This is one of the partial structural schematic diagrams of the battery cell of the present invention.

[0041] Figure 4 for Figure 3 Schematic diagram of the enlarged structure at point A in the middle.

[0042] Figure 5 This is the second schematic diagram of the partial structure of the battery cell of the present invention.

[0043] Figure 6 This is the third schematic diagram of the partial structure of the battery cell of the present invention.

[0044] Figure 7 This is the fourth schematic diagram of the partial structure of the battery cell of the present invention.

[0045] Figure 8 This is the fifth schematic diagram of the partial structure of the battery cell of the present invention.

[0046] Fig. 9 It is a schematic diagram of the structure of the current collecting plate of the present invention.

[0047] The reference numerals are described as follows:

[0048] 100. Battery cell;

[0049] 10. Shell;

[0050] 20. Top cover; 21. Weak area; 22. Liquid injection hole;

[0051] 30. battery cell; 31. tab; 32. center hole;

[0052] 40, current collecting plate; 41, first region; 411, through hole; 412, thinning depression; 42, second region; 421, boss; 4211, first metal layer; 4212, second metal layer; 4213, fifth step; 422, third groove;

[0053] 50. First welding part;

[0054] 60. Second welding part;

[0055] 70, first groove; 71, first step; 72, second step;

[0056] 80, second groove; 81, third step; 84, fourth step;

[0057] a. Height direction of the battery cell; b. Radial direction. DETAILED DESCRIPTION

[0058] For example, certain words are used in the specification and claims to refer to specific components. Those skilled in the art should understand that hardware manufacturers may use different terms to refer to the same component. This specification and claims do not use differences in names as a way to distinguish components, but use differences in the functions of components as the criteria for distinction. For example, "including" mentioned throughout the specification and claims is an open term, so it should be interpreted as "including but not limited to". "Approximately" means that within an acceptable error range, those skilled in the art can solve technical problems within a certain error range and basically achieve technical effects.

[0059] Furthermore, the terms “first”, “second”, etc. are used for descriptive purposes only and are not to be understood as indicating or implying relative importance.

[0060] The term "and / or" in the present invention is only a description of the association relationship of the associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist at the same time, and B exists alone. In addition, the character " / " in the present invention generally indicates that the associated objects before and after are in an "or" relationship.

[0061] The term "plurality" used in the present invention refers to two or more (including two).

[0062] In the invention, unless otherwise clearly specified and limited, the terms "installed", "connected", "connected", "fixed" and the like should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be an indirect connection through an intermediate medium, or it can be the internal communication of two elements. For ordinary technicians in this field, the specific meanings of the above terms in the invention can be understood according to specific circumstances.

[0063] The following will be combined with the attached Figures 1 to 9 The technical solutions in the embodiments of the present invention are described clearly and completely. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0064] In the present invention, in order to solve the problem of low welding efficiency caused by the side welding process for sealing the battery cell, the top welding process is used instead of the side welding process for sealing the battery cell. However, in actual operation, the top cover usually needs to be welded to the collector plate and the shell, which is not only complicated but also time-consuming, significantly reducing the efficiency of the entire welding process.

[0065] In order to solve the above technical problems, the inventor tried to extend the current collecting plate 40 partially between the shell 10 and the top cover 20. Specifically, the inventor arranged a boss 421 on the side of the current collecting plate 40 facing the opening of the shell 10, and the boss 421 is located between the shell 10 and the top cover 20. During the welding process, the shell 10, the current collecting plate 40 and the top cover 20 can be welded together at the same time, thereby simplifying the welding steps and improving the welding efficiency.

[0066] However, the inventors found that, during the welding process, welding the housing 10, the current collecting plate 40 and the top cover 20 together at the same time can effectively improve the welding efficiency, but the welding difficulty also increases accordingly. Specifically, the inventors found that when trying to weld the housing 10, the current collecting plate 40 and the top cover 20 together at one welding point, the welding point needs to withstand stress and deformation from three different components, which greatly increases the risk of welding failure.

[0067] See also Figures 1 to 9 In view of this, the present invention provides a new technical solution, by welding the boss 421 to the shell 10 to form a first welding part 50, and welding the boss 421 to the top cover 20 to form a second welding part 60, the first welding part 50 can effectively ensure the connection strength between the boss 421 and the shell 10, and the second welding part 60 can effectively ensure the connection strength between the boss 421 and the top cover 20. By welding the boss 421 to the shell 10 and the boss 421 to the top cover 20 separately, the welding stress is effectively dispersed and the risk of welding failure is reduced. In addition, when the boss 421 is welded to the shell 10 and the boss 421 is welded to the top cover 20, only two parts are involved. Compared with welding three parts at the same time, the welding process is more controllable, the welding difficulty is reduced, and the welding quality is improved. During the welding process, the boss 421 and the shell 10, and the boss 421 and the top cover 20 can be welded at the same time, and the welding efficiency will not be reduced compared with welding three parts at the same time.

[0068] The electrical device of the embodiment of the present invention includes a battery cell 100; or, a battery. The electrical device may be a car, a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The car may be a fuel car, a gas car, or a new energy car, and the new energy car may be a pure electric car, a hybrid car, or an extended-range car, and the like; the spacecraft includes an airplane, a rocket, a space shuttle, and a spacecraft, and the like; the electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, and the like; the electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, and the like. The embodiments of the present application do not impose any special restrictions on the above-mentioned electrical devices.

[0069] The battery according to the embodiment of the present invention includes a battery cell 100 .

[0070] In a battery, there can be one or more battery cells 100. If there are multiple battery cells 100, the multiple battery cells 100 can be connected in series, in parallel, or in mixed connection. Mixed connection means that the multiple battery cells 100 are both connected in series and in parallel. The multiple battery cells 100 can be directly connected in series, in parallel, or in mixed connection to form a whole; of course, multiple battery cells 100 can also be connected in series, in parallel, or in mixed connection to form a battery module, and then multiple battery modules can be connected in series, in parallel, or in mixed connection to form a whole.

[0071] See also Figures 1 to 9The battery cell 100 of the embodiment of the present invention comprises a shell 10, a top cover 20, a battery cell 30 and a current collecting plate 40, wherein the shell 10 has a receiving cavity; the top cover 20 is buckled with the opening of the shell 10; the battery cell 30 is received in the receiving cavity, and a pole ear 31 is provided at one end of the battery cell 30 facing the top cover 20; the current collecting plate 40 is received in the receiving cavity and is located between the pole ear 31 of the battery cell 30 and the top cover 20, and the current collecting plate 40 has a first area 41 and a second area 42 arranged around the first area 41;

[0072] Among them, the second area 42 is protruded toward the opening relative to the first area 41 to form a boss 421 on the side of the collecting plate 40 facing the opening, the boss 421 is located between the shell 10 and the top cover 20, the boss 421 and the shell 10 are welded to form a first welding portion 50, the boss 421 and the top cover 20 are welded to form a second welding portion 60, the first welding portion 50 and the second welding portion 60 are spaced apart, and the first area 41 is electrically connected to the pole ear 31.

[0073] Compared with the prior art, the battery cell 100 of the embodiment of the present invention, through the coordinated use of the housing 10, the top cover 20, the battery cell 30 and the current collecting plate 40, the top cover 20 is buckled with the opening of the housing 10, the battery cell 30 and the current collecting plate 40 are both accommodated in the accommodating cavity of the housing 10, and the current collecting plate 40 is located between the top cover 20 and the pole ear 31 of the battery cell 30, effectively ensuring the structural stability of the battery cell 100. The first area 41 of the current collecting plate 40 and the second area 42 arranged around the first area 41, the first area 41 is used to be electrically connected to the pole ear 31 of the battery cell 30, and the second area 42 is used to be electrically connected to the housing 10 and the top cover 20, effectively realizing the optimization of the current transmission path of the battery cell 100 and improving the performance of the battery cell 100. By setting the boss 421, the boss 421 is located between the shell 10 and the top cover 20, the boss 421 and the shell 10 are welded to form a first welding portion 50, and the boss 421 and the top cover 20 are welded to form a second welding portion 60, which effectively disperses the welding stress and reduces the risk of welding failure. In addition, when the boss 421 is welded to the shell 10, and the boss 421 is welded to the top cover 20, only two parts are involved. Compared with welding three parts at the same time, the welding process is more controllable, the welding difficulty is reduced, and the welding quality is improved.

[0074] It is understandable that the first welding portion 50 and the second welding portion 60 can be controlled separately. During the welding process, the boss 421 can be welded to the housing 10 to form the first welding portion 50, and then the boss 421 can be welded to the top cover 20 to form the second welding portion 60. Conversely, the boss 421 can be welded to the top cover 20 to form the second welding portion 60, and then the boss 421 can be welded to the housing 10 to form the first welding portion 50.

[0075] Of course, in some embodiments, the boss 421 is welded to the housing 10 to form the first welding portion 50, and the boss 421 is welded to the top cover 20 to form the second welding portion 60. These two steps can also be performed simultaneously. Compared with welding three parts at the same time, such a setting not only ensures welding efficiency, but also reduces welding difficulty.

[0076] Specifically, the extension direction of the first welding part 50 is the same as the extension direction of the second welding part 60, and the extension direction is the height direction a of the battery cell 30. Through the coordinated use of the first welding part 50 and the second welding part 60, the extension direction of the first welding part 50 is the same as the extension direction of the second welding part 60. During the welding process, the boss 421 is welded to the shell 10 to form the first welding part 50, and the boss 421 is welded to the top cover 20 to form the second welding part 60. The welding time can be greatly shortened by emitting two laser beams and welding at the same time. This welding method effectively avoids the waiting time required for welding one by one in the traditional welding process, thereby significantly improving the overall production efficiency. In addition, since the boss 421 is welded to the shell 10, and the boss 421 is welded to the top cover 20 at the same time, it means that the first welding part 50 and the second welding part 60 can reach the required welding temperature and pressure conditions in almost the same time, thereby ensuring the uniformity and consistency of the welding quality. This helps to reduce welding defects, such as discontinuous welds, pores or cracks, and improve the overall structural strength and sealing performance of the battery cell 100.

[0077] See also Figure 3In some embodiments, the distance L3 between the inner edge of the first welding portion 50 and the outer edge of the second welding portion 60 satisfies the relationship: L3 ≥ 3 mm, wherein in the radial direction b, the first welding portion 50 and the second welding portion 60 both have an outer side and an inner side closer to the center hole 32 of the battery cell 30 relative to the outer side. Through the coordinated use of the first welding portion 50 and the second welding portion 60, if the distance between the inner edge of the first welding portion 50 and the outer edge of the second welding portion 60 cannot be too small, that is, when L3 < 3 mm, the distance between the first welding portion 50 and the second welding portion 60 is closer, and the heat generated during welding is more easily transferred and concentrated between the two. This may cause the temperature of the welding area to rise rapidly and speed up the welding speed, but it may also increase the risk of welding deformation because high temperature is more likely to cause material expansion and stress accumulation. Therefore, when L3 ≥ 3 mm, the distance between the first welding portion 50 and the second welding portion 60 is moderate, and the degree of transfer and concentration of the heat generated during welding between the two will be reduced, making the temperature distribution of the welding area more uniform. This helps to reduce local overheating, reduces the risk of welding deformation, and helps to improve the overall quality of the weld. In addition, maintaining an appropriate welding spacing helps to reduce thermal stress and residual stress generated during welding. This is because the larger spacing allows the welding area to expand and contract more freely during heating and cooling, thereby reducing the accumulation and release of stress, and helping to maintain the shape and dimensional stability of the weld. Taking into account the space utilization of the battery cell 100, 3mm≤L3≤5mm, specifically, L3 is 3mm, 3.2mm, 3.5mm, 3.7mm, 3.8mm, 4.0mm, 4.1mm, 4.3mm, 4.5mm, 4.6mm, 4.8mm or 5mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0078] See also Figures 3-4 In some embodiments, the outer edge of the boss 421 forms a first step 71, the inner wall of the housing 10 forms a second step 72, the first step 71 and the second step 72 are spliced ​​into a first groove 70, and the first welding portion 50 is formed in the first groove 70; and / or, the inner edge of the boss 421 forms a third step 81, the outer wall of the top cover 20 forms a fourth step 84, the third step 81 and the fourth step 84 are spliced ​​into a second groove 80, and the second welding portion 60 is formed in the second groove 80. By setting the first groove 70 and the second groove 80, the first welding portion 50 is formed in the first groove 70, and during the welding process, the first welding portion 50 can be positioned by the first groove 70, thereby ensuring the accuracy of welding. Similarly, the second welding portion 60 is formed in the second groove 80, and during the welding process, the second welding portion 60 can be positioned by the second groove 80, thereby ensuring the accuracy of welding.

[0079] At the same time, the first groove 70 and the second groove 80 can also effectively avoid the problem of molten material overflowing. Specifically, during welding, the molten welding material will flow along the weld. The presence of the first groove 70 and the second groove 80 can effectively limit the flow range of these molten materials, preventing them from overflowing the weld area and affecting the appearance quality or performance of the product battery cell 100. In addition, the first groove 70 and the second groove 80 can be used as a temporary storage space to accommodate the welding slag generated during the welding process, so that after the welding is completed, the welding slag can be cleaned more conveniently to keep the product clean and the integrity of the welding part.

[0080] See also Figure 5 In some embodiments, along the radial direction b, the width L1 of the first groove 70 satisfies the relationship: L1 ≥ 0.5 mm. By setting the width L1 of the first groove 70, when L1 ≥ 0.5 mm, the width of the first groove 70 is wider, which provides a larger operating space and positioning accuracy for the welding process. The wider width of the first groove 70 can not only more effectively accommodate and guide the molten material to prevent it from overflowing, but also provide a larger storage space for the welding slag, making the welding slag easier to collect and process.

[0081] Taking into account the space utilization of the battery cell 100, 0.5mm≤L1≤1mm. Specifically, L1 is 0.5mm, 0.55mm, 0.57mm, 0.6mm, 0.64mm, 0.68mm, 0.7mm, 0.71mm, 0.74mm, 0.76mm, 0.8mm, 0.83mm, 0.86mm, 0.89mm, 0.9mm, 0.92mm, 0.95mm, 0.97mm or 1mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0082] And / or, the width L2 of the second groove 80 satisfies the relationship: L2 ≥ 0.5 mm. By setting the width L2 of the second groove 80, when L2 ≥ 0.5 mm, the width of the second groove 80 is wider, which provides a larger operating space and positioning accuracy for the welding process, and the wider width of the second groove 80 can not only more effectively accommodate and guide the molten material to prevent it from overflowing, but also provide a larger storage space for the welding slag, making the welding slag easier to collect and process.

[0083] Taking into account the space utilization of the battery cell 100, 0.5mm≤L2≤1mm. Specifically, L2 is 0.5mm, 0.55mm, 0.57mm, 0.6mm, 0.64mm, 0.68mm, 0.7mm, 0.71mm, 0.74mm, 0.76mm, 0.8mm, 0.83mm, 0.86mm, 0.89mm, 0.9mm, 0.92mm, 0.95mm, 0.97mm or 1mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0084] See also Figures 3 to 8 In some embodiments, the depth of the first groove 70 is 0.4 to 0.6 mm. By setting the depth of the first groove 70, the depth of the first groove 70 cannot be too deep or too shallow. When the depth of the first groove 70 is too deep, that is, the depth of the first groove 70 is greater than 0.6 mm, it is difficult to accurately control the flow and distribution of the molten material during the welding process, which increases the difficulty of welding. At the same time, the overly deep first groove 70 may weaken the structural strength of the surrounding materials, making the welding area easily welded. When the depth of the first groove 70 is too shallow, that is, the depth of the first groove 70 is less than 0.4 mm, the depth of the first groove 70 is insufficient and cannot effectively accommodate the molten material, resulting in the molten material overflowing and affecting the welding quality. At the same time, due to the insufficient depth of the first groove 70, after the boss 421 and the shell 10 are welded, the first welding portion 50 protrudes from the surface of the shell 10, which not only affects the appearance of the battery cell 100, but also may interfere with other components in the subsequent assembly process, resulting in assembly difficulties or inability to assemble, which may affect the overall function and performance of the product. Therefore, setting the depth of the first groove 70 to 0.4 to 0.6 mm can not only reduce the difficulty of welding and ensure the welding quality, but also avoid the overflow of molten material and the flatness of the appearance of the battery cell 100 after welding, thereby improving the structural strength and appearance quality of the battery cell 100, thereby reducing the defective rate in the production process and improving production efficiency, while reducing the failure rate of the battery cell 100 caused by welding problems and extending the service life of the product.

[0085] Specifically, the depth of the first groove 70 is 0.4 mm, 0.41 mm, 0.43 mm, 0.45 mm, 0.48 mm, 0.5 mm, 0.52 mm, 0.55 mm, 0.57 mm, 0.59 mm or 0.6 mm, but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0086] And / or, the depth of the second groove 80 is 0.4 to 0.6 mm. By setting the depth of the second groove 80, the depth of the second groove 80 cannot be too deep or too shallow. When the depth of the second groove 80 is too deep, that is, the depth of the second groove 80 is greater than 0.6 mm, it is difficult to accurately control the flow and distribution of the molten material during the welding process, which increases the difficulty of welding. At the same time, the overly deep second groove 80 may weaken the structural strength of the surrounding materials, making the welding area easily welded. When the depth of the second groove 80 is too shallow, that is, the depth of the second groove 80 is less than 0.4 mm, the depth of the second groove 80 is insufficient and cannot effectively accommodate the molten material, resulting in the molten material possibly overflowing, affecting the welding quality. At the same time, due to the insufficient depth of the second groove 80, after the boss 421 and the shell 10 are welded, the second welding portion 60 protrudes from the surface of the shell 10, which not only affects the appearance of the battery cell 100, but also may interfere with other components in the subsequent assembly process, resulting in assembly difficulties or inability to assemble, which may affect the overall function and performance of the product. Therefore, setting the depth of the second groove 80 to 0.4 to 0.6 mm can not only reduce the difficulty of welding and ensure the welding quality, but also avoid the overflow of molten material and the flatness of the appearance of the battery cell 100 after welding, thereby improving the structural strength and appearance quality of the battery cell 100, thereby reducing the defective rate in the production process and improving production efficiency, while reducing the failure rate of the battery cell 100 caused by welding problems and extending the service life of the product.

[0087] Specifically, the depth of the second groove 80 is 0.4 mm, 0.41 mm, 0.43 mm, 0.45 mm, 0.48 mm, 0.5 mm, 0.52 mm, 0.55 mm, 0.57 mm, 0.59 mm or 0.6 mm, but is not limited to the listed values, and other values ​​within the numerical range are also applicable.

[0088] See also Figures 2 to 9In some embodiments, a fifth step 4213 is formed on the inner side of the boss 421, the top cover 20 is mounted on the fifth step 4213, and the side of the top cover 20 facing away from the battery cell 30 is flush with the end face of the boss 421. By forming the fifth step 4213 on the inner side of the boss 421 and providing a stable mounting base for the top cover 20, it is possible to ensure that the connection between the top cover 20 and the boss 421 is more secure, thereby helping to enhance the stability of the entire structure. At the same time, the top cover 20 is mounted on the fifth step 4213, and the side of the top cover 20 facing away from the battery cell 30 is flush with the end face of the boss 421, which can not only effectively improve the space utilization of the battery cell 100, but also ensure the flatness of the appearance of the battery cell 100, which helps to reduce friction and wear caused by uneven surfaces, extend the service life of the product, and avoid interference with other components due to uneven surfaces during the subsequent assembly process, resulting in assembly difficulties or inability to assemble, which may affect the overall function and performance of the product.

[0089] See also Figure 8 In some embodiments, the second region 42 forms a third groove 422 corresponding to the boss 421 on the side of the current collecting plate 40 away from the outlet, and the distance L7 between the bottom wall of the third groove 422 and the battery cell 30 is less than the distance L8 between the step surface of the fifth step 4213 and the battery cell 30. By designing the third groove 422 on the current collecting plate 40 and corresponding to the boss 421, the weight of the current collecting plate 40 is effectively reduced, and the space utilization rate of the battery cell 100 is improved. In addition, by making the distance L7 between the bottom wall of the third groove 422 and the battery cell 30 less than the distance L8 between the step surface of the fifth step 4213 and the battery cell 30, the depth of the first groove 70 and the depth of the second groove 80 are ensured while the weight of the current collecting plate 40 is effectively reduced, thereby ensuring the structural strength of the current collecting plate 40.

[0090] See also Figure 5In some embodiments, a weak area 21 is provided on the top cover 20, and the distance L4 between the outer edge of the weak area 21 and the inner edge of the second welding part 60 satisfies the relationship: L4 ≥ 4 mm, wherein in the radial direction b, the weak area 21 and the second welding part 60 both have an outer side, and an inner side closer to the center hole 32 of the battery cell 30 relative to the outer side. By setting the weak area 21, the weak area 21 is set on the top cover 20. When short circuit, overcharging, etc. occur, thermal runaway may occur inside the battery cell 100, resulting in a sudden increase in pressure. When the internal pressure of the battery cell 100 reaches the threshold, it ruptures along the weak area 21, and releases the internal pressure outward to prevent the battery cell 100 from exploding or catching fire, thereby improving safety. In addition, since the thickness of the weak area 21 is relatively thin, when L4 ≥ 4 mm, it can effectively ensure that the outer edge of the weak area 21 and the inner edge of the second welding part 60 maintain an appropriate distance, thereby avoiding the heat generated during the welding process from affecting the weak area 21.

[0091] Taking into account the space utilization of the battery cell 100, 4mm≤L4≤6mm, specifically, L4 is 4mm, 4.3mm, 4.5mm, 4.7mm, 5mm, 5.2mm, 5.4, 5.6mm, 5.8mm, 5.9mm or 6mm, but is not limited to the listed values, and other unlisted values ​​within the numerical range are also applicable.

[0092] The inventor further discovered that, since the material of the collecting plate 40 is different from that of the shell 10 and the top cover 20, large tensile stress is easily generated during the welding process. Especially in a high-temperature welding environment, different materials have different thermal expansion coefficients, which further aggravates the phenomenon of stress concentration, thereby increasing the risk of crack formation. Therefore, in the process of trying to weld the boss 421 to the shell 10 to form the first welding portion 50, and the boss 421 to the top cover 20 to form the second welding portion 60, the inventor discovered that the stress problem caused by this multi-material welding not only increases the difficulty of welding, but also makes the first welding portion 50 and the second welding portion 60 very prone to cracks.

[0093] See also Figures 6 to 8In view of this, the present invention provides another technical solution, wherein the boss 421 includes a first metal layer 4211, the first metal layer 4211 and the shell 10 are welded to form a first welding portion 50, and the first metal layer 4211 and the top cover 20 are welded to form a second welding portion 60; wherein the first metal layer 4211 and the shell 10 are made of the same material; and / or, the first metal layer 4211 and the top cover 20 are made of the same material. By setting the first metal layer 4211, the first metal layer 4211 and the shell 10 are made of the same material, and the boss 421 is welded to form the first welding portion 50 by the first metal layer 4211 and the shell 10, thereby effectively reducing the stress concentration problem caused by different materials during the welding process. Similarly, when the first metal layer 4211 and the top cover 20 are made of the same material, the second welding portion 60 formed by welding the boss 421 and the top cover 20 can also reduce stress concentration, thereby reducing the risk of cracks. Through this design, the difference in thermal expansion coefficients between different materials can be effectively reduced, thereby reducing the tensile stress generated during welding, which not only reduces the difficulty of welding, but also reduces the risk of crack formation, thereby ensuring the structural stability and service life of the battery cell 100.

[0094] See also Figures 6 to 8 In some embodiments, along the height direction a of the battery cell 30, the boss 421 also includes a second metal layer 4212 stacked with the first metal layer 4211, and the second metal layer 4212 is made of a different material from the first metal layer 4211. Through the arrangement of the boss 421, the boss 421 includes a first metal layer 4211 and a second metal layer 4212 of different materials, and the first metal layer 4211 is arranged on the second metal layer 4212 along the height direction a of the battery cell 30, so that the first metal layer 4211 is effectively formed on the exposed portion of the boss 421. During the welding process, the boss 421 can be welded with the shell 10 and the top cover 20 through the first metal layer 4211 to achieve the same material, effectively reducing the difference in thermal expansion coefficients between different materials, thereby reducing the tensile stress generated during the welding process, which not only reduces the difficulty of welding, but also reduces the risk of crack formation, thereby ensuring the structural stability and service life of the battery cell 100. In addition, the first metal layer 4211 and the second metal layer 4212 can be stacked by existing composite plate materials, and the principle of composite plates can be utilized to make the boss 421 exhibit the same or similar welding characteristics as the shell 10 or the top cover 20 during welding, thereby achieving the effect of welding the same material.

[0095] In some embodiments, the shell 10 is made of aluminum, the top cover 20 is made of aluminum, the first metal layer 4211 is aluminum, and the second metal layer 4212 is copper. The first metal layer 4211 and the shell 10, as well as the first metal layer 4211 and the top cover 20 are welded with the same material, which reduces the difficulty of welding. The pole ear 31 is a negative pole ear, made of copper foil, and the second metal layer 4212 and the pole ear 31 are welded with the same material to ensure the electrical connection effect. In addition, through the coordinated use of the first metal layer 4211 and the second metal layer 4212, the first metal layer 4211 is aluminum, which has good electrical conductivity and welding performance, and effectively ensures the compatibility of the boss 421 with the shell 10 and the top cover 20 during welding, and the second metal layer 4212 is copper, which has good mechanical strength and thermal conductivity, which effectively enables the second metal layer 4212 to provide support for the first metal layer 4211, and the first metal layer 4211 is not easy to deform during the welding process, thereby improving the reliability of welding. In addition, the aluminum and copper composite can take advantage of the advantages of their respective materials, so that the battery cell 100 has sufficient structural strength and heat dissipation performance while maintaining lightweight, effectively ensuring the performance and safety of the battery cell 100.

[0096] See also Figures 7-8 In some embodiments, the distance L5 between the side of the top cover 20 facing the battery cell 30 and the battery cell 30 is less than the distance L6 between the bonding surface of the first metal layer 4211 and the second metal layer 4212 and the battery cell 30. In the battery cell 100, the electrolyte is not only a medium for electrochemical reaction, but also corrosive. If the distance L5 between the side of the top cover 20 facing the battery cell 30 and the battery cell 30 is greater than or equal to the distance L6 between the bonding surface of the first metal layer 4211 and the second metal layer 4212 and the battery cell 30, the electrolyte is easy to penetrate into the bonding surface of the first metal layer 4211 and the second metal layer 4212 along the side of the top cover 20 facing the battery cell 30, corroding the first metal layer 4211 and the second metal layer 4212, which will not only weaken the structural strength of the first metal layer 4211 and the second metal layer 4212, but also may cause the first metal layer 4211 and the second metal layer 4212 to fall off or be perforated, resulting in an internal short circuit of the battery cell 100, seriously affecting the safety and service life of the battery. Therefore, the penetration of electrolyte can be effectively prevented by making the distance L5 between the side of the top cover 20 facing the battery cell 30 and the battery cell 30 smaller than the distance L6 between the bonding surface of the first metal layer 4211 and the second metal layer 4212 and the battery cell 30. This structural setting not only improves the structural safety of the battery cell 100, but also prolongs the service life of the battery.

[0097] When the first metal layer 4211 is aluminum and the second metal layer 4212 is copper, aluminum is more easily corroded by the electrolyte than copper. Therefore, by setting the second metal layer 4212 below the first metal layer 4211, the first metal layer 4211 can be protected; and by setting L5 to be smaller than L6, the top cover 20 can cover the copper-aluminum joint surface, further preventing the penetration of the electrolyte and reducing the risk of the first metal layer 4211 being corroded.

[0098] In some embodiments, the top cover 20 is provided with a liquid injection hole 22, and the first region 41 is provided with a through hole 411 corresponding to the position of the liquid injection hole 22. Through the coordinated use of the liquid injection hole 22 and the through hole 411, during liquid injection, the electrolyte enters the interior of the battery cell 100 through the liquid injection hole 22 and the through hole 411, infiltrates the battery cell 30, and effectively achieves the infiltration of the battery cell 30.

[0099] In some embodiments, along the height direction a of the battery cell 30, the injection hole 22 and / or the through hole 411 are located on the same axis as the center hole 32 of the battery cell 30. Since the injection hole 22 and / or the through hole 411 are located on the same axis as the center hole 32 of the battery cell 30, the electrolyte can directly penetrate along the center line of the battery cell 30 when injected, ensuring that the electrolyte is evenly distributed inside the battery cell 30. This not only helps to improve the energy density and cycle life of the battery, but also reduces the performance differences caused by uneven distribution of the electrolyte.

[0100] In some embodiments, a thinning recess 412 is provided on the first region 41, and the bottom wall of the thinning recess 412 is welded to the tab 31 of the battery cell 30, and corresponds to the welding track of the tab 31 of the battery cell 30. By setting the thinning recess 412, the bottom wall of the thinning recess 412 is used to weld to the tab 31 of the battery cell 30, which effectively makes the welding area between the first region 41 and the tab 31 of the battery cell 30 thinner, thereby reducing the difficulty of welding the first region 41 and the tab 31 of the battery cell 30. In addition, due to the setting of the thinning recess 412, the weight of the current collecting plate 40 is further reduced, thereby effectively reducing the overall weight of the battery cell 100 and improving the energy density of the battery cell 100.

[0101] Specifically, the thinning recess 412 is disposed around the through hole 411 to avoid the through hole 411 and ensure the structural strength of the first region 41 .

[0102] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

Claims

1. A battery cell, characterized in that: include: A housing (10) having a receiving cavity; A top cover (20) that snaps into place with the opening of the housing (10); A battery cell (30) is accommodated in the accommodation cavity, and a pole ear (31) is provided at one end of the battery cell (30) facing the top cover (20); and A current collecting plate (40) is accommodated in the accommodation cavity and is located between the pole ear (31) of the battery cell (30) and the top cover (20), wherein the current collecting plate (40) has a first area (41) and a second area (42) arranged around the first area (41); The second region (42) is arranged to protrude toward the opening relative to the first region (41) to form a boss (421) on the side of the collecting plate (40) facing the opening, the boss (421) is located between the shell (10) and the top cover (20), the boss (421) and the shell (10) are welded to form a first welding portion (50), the boss (421) and the top cover (20) are welded to form a second welding portion (60), the first welding portion (50) and the second welding portion (60) are arranged at intervals, and the first region (41) is electrically connected to the pole lug (31).

2. The battery cell according to claim 1, characterized in that: The boss (421) comprises a first metal layer (4211), the first metal layer (4211) and the shell (10) are welded to form the first welding portion (50), and the first metal layer (4211) and the top cover (20) are welded to form the second welding portion (60); Wherein, the first metal layer (4211) and the shell (10) are made of the same material; And / or, the first metal layer (4211) and the top cover (20) are made of the same material.

3. The battery cell according to claim 2, characterized in that: Along the height direction (a) of the battery core (30), the boss (421) further includes a second metal layer (4212) stacked with the first metal layer (4211), and the second metal layer (4212) and the first metal layer (4211) are made of different materials.

4. The battery cell according to claim 3, characterized in that: The first metal layer (4211) is aluminum, and the second metal layer (4212) is copper.

5. The battery cell according to claim 3, characterized in that: A distance L5 between a side of the top cover (20) facing the battery core (30) and the battery core (30) is smaller than a distance L6 between a joining surface of the first metal layer (4211) and the second metal layer (4212) and the battery core (30).

6. The battery cell according to claim 1, characterized in that: The extension direction of the first welding portion (50) is the same as the extension direction of the second welding portion (60), and the extension direction is the height direction (a) of the battery core (30).

7. The battery cell according to claim 6, characterized in that: A distance L3 between an inner edge of the first welding portion (50) and an outer edge of the second welding portion (60) satisfies the relationship: L3 ≥ 3 mm, wherein, in the radial direction (b), the first welding portion (50) and the second welding portion (60) both have an outer side and an inner side that is closer to the center hole (32) of the battery cell (30) relative to the outer side.

8. The battery cell according to claim 6, characterized in that: The outer edge of the boss (421) forms a first step (71), the inner wall of the shell (10) forms a second step (72), the first step (71) and the second step (72) are spliced ​​to form a first groove (70), and the first welding portion (50) is formed in the first groove (70); And / or, the inner edge of the boss (421) forms a third step (81), the outer wall of the top cover (20) forms a fourth step (84), the third step (81) and the fourth step (84) are spliced ​​into a second groove (80), and the second welding portion (60) is formed in the second groove (80).

9. The battery cell according to claim 8, characterized in that: Along the radial direction (b), the width L1 of the first groove (70) satisfies the relationship: L1 ≥ 0.5 mm; And / or, the width L2 of the second groove (80) satisfies the relationship: L2 ≥ 0.5 mm.

10. The battery cell according to claim 8, characterized in that: The depth of the first groove (70) is 0.4-0.6 mm; And / or, the depth of the second groove (80) is 0.4-0.6 mm.

11. The battery cell according to any one of claims 1 to 10, characterized in that: A fifth step (4213) is formed on the inner side of the boss (421), the top cover (20) is mounted on the fifth step (4213), and a side of the top cover (20) facing away from the battery cell (30) is flush with an end face of the boss (421).

12. The battery cell according to claim 11, characterized in that: The second region (42) forms a third groove (422) corresponding to the boss (421) on the side of the current collecting plate (40) away from the opening, and the distance L7 between the bottom wall of the third groove (422) and the battery cell (30) is smaller than the distance L8 between the step surface of the fifth step (4213) and the battery cell (30).

13. The battery cell according to any one of claims 1 to 10, characterized in that: A weak area (21) is provided on the top cover (20), and a distance L4 between an outer edge of the weak area (21) and an inner edge of the second welding portion (60) satisfies the relationship: L4 ≥ 4 mm, wherein, in a radial direction (b), the weak area (21) and the second welding portion (60) both have an outer side and an inner side that is closer to the center hole (32) of the battery cell (30) relative to the outer side.

14. A battery, characterized in that: A battery cell comprising the battery cell according to any one of claims 1 to 13.

15. An electrical device, characterized in that: A battery cell comprising any one of claims 1 to 13; Or, the battery according to claim 14.

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