A single battery, a battery pack and an electronic device

Abstract

The utility model provides a single battery, battery pack and electronic device, this single battery includes casing, electrode assembly, lid and current collection member, the casing includes side wall, and the side wall surrounds to have the opening, electrode assembly installs in the casing, the lid blocks the opening, and is welded fixed with the side wall, current collection member sets up between the lid and electrode assembly, and current collection member and the current collection department of electrode assembly electric connection, wherein, at the side of lid away from electrode assembly, the lid includes thinning area, and the side surface of thinning area away from electrode assembly recess forms first recess, and the welding mark is formed by the welding connection of lid, side wall and current collection member, and the welding mark is located in first recess. The utility model can improve the technical problem of the welding quality of prior art because of the big thickness of lid, reduces the safety and the yield of single battery.

Description

Technical Field

[0001] This utility model relates to the field of battery technology, and in particular to a single cell battery, a battery pack and an electronic device. Background Technology

[0002] Existing single-cell batteries typically have a cover welded to the opening of the casing to achieve a seal. To meet the internal pressure requirements of the single-cell battery, the cover needs to have a certain thickness. However, thicker covers often require higher laser welding energy during welding, especially in through-hole welding processes, where this requirement is even more pronounced. High-energy welding not only easily leads to defects such as bursts, affecting weld quality, but the resulting heat-affected zone may also damage internal electrode components, potentially causing internal short circuits within the single-cell battery.

[0003] Therefore, optimizing the matching between the cover thickness and welding process while ensuring the strength of the cover structure has become a key issue in improving the safety and yield of individual cells. Utility Model Content

[0004] This utility model provides a single battery cell, a battery pack, and an electronic device. By improving the structure of the cover, it can improve the technical problem in the prior art where the large thickness of the cover affects the welding quality and reduces the safety and yield of the single battery cell.

[0005] This utility model provides a single-cell battery, which includes a casing, an electrode assembly, a cover, and a current collector. The casing includes a side wall that forms an opening. The electrode assembly is installed inside the casing. The cover seals the opening and is welded to the side wall. The current collector is disposed between the cover and the electrode assembly and is electrically connected to the current collection portion of the electrode assembly. On the side of the cover away from the electrode assembly, the cover includes a thinning region. The side of the thinning region away from the electrode assembly is recessed to form a first groove. The cover, the side wall, and the current collector are welded together to form a weld mark, which is located in the first groove.

[0006] In one embodiment of the present invention, the cover further includes a central region, a first groove surrounding the outer periphery of the central region, and the side of the thinned area near the electrode assembly is flush with the side of the central region near the electrode assembly.

[0007] In one embodiment of the present invention, along the radial direction of the cover, the thinning area is connected to the inner wall of the sidewall, and the first groove extends through the thinning area on the side facing the sidewall to form an open opening. The sidewall has a first end face near the opening, and the first end face is flush with the bottom wall of the first groove; or the first end face is higher than the bottom wall of the first groove but not higher than the top surface of the cover.

[0008] In one embodiment of the present invention, the current collecting member includes a main body and a welding pin connected to the main body and in contact with the thinning area. The welding pin has a first side surface and a first end face on the side wall near the opening. The first side surface and the first end face are flush to form an overlapping plane. The thinning area overlaps at least partially on the overlapping plane.

[0009] In one embodiment of this utility model, the thinning area is formed by a thinning process, and at least part of the surface of the first groove has an anti-corrosion layer; the cover is subjected to nickel plating anti-corrosion treatment before the thinning area is formed, and the composition of the weld pool of the solder stamp includes nickel.

[0010] In one embodiment of the present invention, a stepped portion is provided on the inner wall of the sidewall. The stepped portion has a supporting surface. Along the thickness direction of the cover, the current collecting member includes a main body and welding pins connected to the main body and in contact with the thinning area. The welding pins of the current collecting member are at least partially clamped between the supporting surface and the thinning area. The weld pool of the solder is at least partially formed inside the stepped portion. The radial width of the supporting surface is W1, the thickness at the opening of the sidewall is T5, and 0.05mm≤W1<T5, where 0.25mm≤T5≤0.6mm. The thickness of the welding pins of the current collecting member is T3, and the thickness of the main body is T4, where T3≥T4, and 0.1mm≤T4≤0.5mm.

[0011] In one embodiment of the present invention, the welding pin has at least one bent portion. The welding pin includes a first bent segment and a second bent segment connected to each other. The second bent segment is connected to the body portion through the first bent segment. The second bent segment is parallel to the surface of the cover facing the electrode assembly, and the end face of the second bent segment is perpendicular to the inner wall of the sidewall. The depth of the first groove is T2, and 0.05mm≤T2≤0.5mm.

[0012] In one embodiment of the present invention, along the radial direction of the cover, the thinned area of ​​the cover is connected to the inner wall of the sidewall, and the end face of the sidewall near the opening protrudes from the end face of the electrode assembly in the central region, and the protrusion height is D1, and 0.05mm≤D1≤0.4mm.

[0013] This utility model also provides a battery pack, which includes any of the individual cells described in the above embodiments.

[0014] The present invention provides another electronic device, which includes the battery pack in the above embodiments.

[0015] The beneficial effects of this utility model are as follows: By setting a locally thinned area on the cover and welding the current collector and sidewalls to this thinned area, this utility model has several advantages. First, in terms of welding process, the thinned area reduces the material thickness of the cover at the welding area, thereby reducing the energy required for welding, improving defects such as bursts and spatter caused by high-energy welding, and increasing the welding yield. Simultaneously, the reduced welding heat also shrinks the heat-affected zone, which helps reduce thermal damage to internal electrode components and lowers the risk of internal short circuits caused by heat, thus improving the safety performance of the individual battery. Second, in terms of structural strength and safety, the locally thinned design of the cover optimizes the matching of the welding area while ensuring the overall strength of the cover, avoiding a decrease in the structural strength of the cover due to overall thinning, thereby ensuring the voltage withstand performance of the individual battery.

[0016] Furthermore, regarding weld pool control and assembly compatibility, the first groove, formed by the recess of the thinned area towards the electrode assembly and the solder mark located within it, effectively constrains the weld pool, preventing its diffusion and thus improving weld quality consistency. Moreover, the first groove's ability to accommodate the solder mark helps ensure the flatness of the cover's end face, preventing the solder mark height from affecting the assembly compatibility of individual cells and facilitating subsequent module integration. Attached Figure Description

[0017] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application. It is obvious that the drawings described below are merely some embodiments of this application, and those skilled in the art can obtain other drawings based on these drawings without any inventive effort.

[0018] In the attached diagram:

[0019] Figure 1 This is a cross-sectional view of the overall structure of a single battery provided in an embodiment of the present invention;

[0020] Figure 2 This is a schematic diagram of the structure of the electrode assembly in a single-cell battery provided in one embodiment of the present invention;

[0021] Figure 3 for Figure 1 A magnified view of a portion of region A in the middle;

[0022] Figure 4 This is a partial structural diagram of the first groove mounting position in one embodiment of the present invention;

[0023] Figure 5This is a partial structural diagram of the first groove mounting position in another embodiment of the present invention;

[0024] Figure 6 This is a partial structural diagram of the first groove mounting position in another embodiment of the present invention;

[0025] Figure 7 This is a partial structural diagram of a thinning area in one embodiment of the present invention, where the thinning area is provided with both a first groove and a second groove.

[0026] Figure 8 This is a schematic diagram of a structure in which a thinning zone is provided in a circumferential partial area of ​​the cover body in one embodiment of the present invention;

[0027] Figure 9 for Figure 8 A schematic diagram of the welding positions of the cover, sidewall, and flow collection component in the embodiment;

[0028] Figure 10 This is a schematic diagram of the structure of a battery pack provided in an embodiment of the present invention;

[0029] Figure 11 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention.

[0030] The attached figures are labeled as follows:

[0031] 100. Single cell; 10. Casing; 11. Sidewall; 111. Stepped portion; 1111. Support surface; 112. First end face; 12. Opening; 13. End wall; 20. Electrode assembly; 21. Positive electrode; 211. Positive current collector; 212. First coated area; 213. First uncoated area; 22. Separator; 23. Negative electrode; 231. Negative current collector; 232. Second coated area; 233. Second uncoated area; 24. Negative electrode tab; 25. Positive electrode tab; 30. Cover; 31. Thinning area; 311. First groove; 3111 312. Second groove; 313. First plane; 32. Central area; 321. Second plane; 322. Top surface; 40. Current collector; 41. Overlapping plane; 42. Body part; 43. Welding pin; 431. First side; 44. Bending part; 441. First bending section; 442. Second bending section; 4421. Second end face; 50. Weld mark; 51. Weld pool; 200. Battery pack; 201. Housing; 2011. First housing part; 2012. Second housing part; 300. Electronic device; 310. Working part. Detailed Implementation

[0032] The following specific examples illustrate the implementation of this utility model. Those skilled in the art can easily understand other advantages and effects of this utility model from the content disclosed in this specification. This utility model can also be implemented or applied through other different specific embodiments. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of this utility model. In the absence of conflict, the following embodiments and features in the embodiments can be combined with each other.

[0033] It should be noted that the illustrations provided in the following embodiments are only schematic representations of the basic concept of the present invention. The drawings only show the components related to the present invention and are not drawn according to the actual number, shape and size of the components. In actual implementation, the form, quantity and proportion of each component can be arbitrarily changed, and the layout of the components may also be more complex.

[0034] In the following description, numerous details are explored to provide a more thorough explanation of embodiments of the present invention. However, it will be apparent to those skilled in the art that embodiments of the present invention may be practiced without these specific details. In other embodiments, well-known structures and devices are shown in block diagram form rather than in detail to avoid obscuring embodiments of the present invention.

[0035] Please see Figures 1 to 11 This utility model provides a single battery 100, a battery pack 200, and an electronic device 300. The single battery 100 has a thinning area 31 partially provided in the cover 30, and the side wall 11 and the current collector 40 are welded to the thinning area 31. This can ensure the overall structural strength of the cover 30, improve the welding process at the welding position of the cover 30, improve the welding quality, and thus improve the safety performance and product yield of the single battery 100.

[0036] In this invention, the single battery cell 100 may include lithium-ion batteries, lithium-sulfur batteries, sodium-lithium-ion batteries, sodium-ion batteries, or magnesium-ion batteries, etc., and the embodiments of this invention are not limited to this. The single battery cell 100 may be cylindrical, flat, cuboid, or other shapes, etc., and the embodiments of this invention are not limited to this either.

[0037] Please see Figure 1 The structure of the single cell 100 is further described, which includes: a housing 10, an electrode assembly 20, a cover 30, and a current collector 40.

[0038] Please see Figure 1The housing 10 includes an end wall 13 and a side wall 11 surrounding the end wall 13. As long as a stable sealing and electrical connection can be formed, the connection between the end wall 13 and the side wall 11 can be achieved in various ways, such as integral stamping, integral casting, or separate welding. The circumference of the side wall 11 is not limited; it can be cylindrical or prismatic, or it can be along any other closed-loop contour that can match the end wall 13. In this embodiment, the outer edge of the end wall 13 is circular, and the side wall 11 is cylindrical and surrounds the outer edge of the end wall 13, with a circular opening 12 formed at the end of the side wall 11 opposite to the end wall 13.

[0039] The housing 10, formed by the end wall 13 and the side wall 11, has a receiving cavity for accommodating the electrode assembly 20, electrolyte, and other necessary battery components. Specifically, the diameter of the housing 10 can be determined according to the specific dimensions of the electrode assembly 20, for example, a diameter of 46mm and heights of 80mm, 95mm, or 120mm. The housing 10 can be made of various materials, such as copper, iron, aluminum, steel, or aluminum alloy. To prevent rusting during long-term use, a rust-preventive material, such as nickel, can be plated onto the surface of the housing 10.

[0040] Please see Figure 1 The electrode assembly 20 is disposed inside the housing 10, and the housing 10 may contain one or more electrode assemblies 20. The electrode assembly 20 is the component in the single cell where the electrochemical reaction occurs, and the electrode assembly 20 includes a current collector. The current collector refers to the part of the electrode assembly 20 (such as the positive or negative electrode) used to collect and conduct current, and the electrode assembly 20 is connected to the external circuit through the current collector. There are various structural forms of the current collector. For example, the current collector can be a traditional tab structure, that is, the tab is a metal sheet extending from the electrode sheet, usually made of aluminum foil (positive electrode) or copper foil (negative electrode). The current collector can also be a tablessless structure, that is, the tab shape is directly cut into the current collector by laser, and then these cut tabs are welded to the external electrical connector. The current collector can also be a full tab structure, that is, the entire positive / negative current collector is turned into a tab, and the current collector is fully connected to the housing 10 or current collector component of the single cell 100 through the current collector.

[0041] Please see Figure 2 Optionally, in one embodiment, the current collector of the electrode assembly 20 is a tab structure. Specifically, the electrode assembly 20 includes a positive electrode 21, a diaphragm 22, and a negative electrode 23 that are axially wound around the housing 10.

[0042] The positive electrode 21 includes a positive current collector 211 and a positive active material layer coated on the positive current collector 211. A first coated area 212 coated with the positive active material layer and a first uncoated area 213 uncoated with the positive active material layer are formed on the positive current collector 211. The first coated area 212 and the first uncoated area 213 are arranged along the axial direction of the housing 10. The first uncoated area 213 extends to the outside of the separator 22 at one end in the height direction of the single cell and is bent towards the axis of the housing 10 to form a stacked positive electrode tab 25, i.e., a positive current collector.

[0043] The negative electrode 23 includes a negative electrode current collector 231 and a negative electrode active material layer coated on the negative electrode current collector 231. A second coated area 232 coated with the negative electrode active material layer and a second uncoated area 233 uncoated with the negative electrode active material layer are formed on the negative electrode current collector 231. The second coated area 232 and the second uncoated area 233 are arranged along the axial direction of the housing 10. The second uncoated area 233 extends to the other end of the single cell height direction to the outside of the separator 22 and bends towards the axis of the housing 10 to form a stacked negative electrode tab 24, i.e., a negative electrode current collector.

[0044] A separator 22 is disposed between the positive electrode 21 and the negative electrode 23 to isolate the positive and negative active material layers. Taking a lithium-ion single-cell battery as an example, the positive current collector 211 can be made of aluminum, and the positive active material layer includes the positive active material, which can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative current collector 231 can be made of copper, and the negative active material layer includes the negative active material, which can be carbon or silicon, etc. The substrate material of the separator 22 can be polypropylene (PP) or polyethylene (PE), etc. To protect and insulate the electrode assembly 20, an insulating film can also be wrapped around the electrode assembly 20. The insulating film can be synthesized from PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or other polymer materials.

[0045] Please see Figure 1 and Figure 2 Furthermore, in this invention, the positive electrode tab 25 faces either the end wall 13 or the opening 12, while the negative electrode tab 24 faces the other end of the housing 10. In this embodiment, the positive electrode tab 25 faces the end wall 13 and is electrically connected to the electrode terminal located at the end wall 13, making the electrode terminal positively charged. The negative electrode tab 24 faces the opening 12, and the housing 10 is electrically connected to the negative electrode tab 24, thus making it negatively charged. However, in another embodiment, the negative electrode tab 24 can be connected to the electrode terminal, and the positive electrode tab 25 can be connected to the housing 10.

[0046] The current collector 40 is disposed within the housing 10 and located between the cover 30 and the electrode assembly 20. The current collector 40 is electrically connected to the current collection section of the electrode assembly 20. Specifically, in this embodiment, the current collector 40 is electrically connected to the negative electrode tab 24 in the above embodiment.

[0047] Please see Figure 3 Along the thickness direction of the cover 30, on the side of the cover 30 facing away from the electrode assembly 20, the cover 30 includes a thinning region 31, and at least a portion of the current collecting member 40 contacts the surface of the thinning region 31 facing the electrode assembly 20. The thinning region 31 is located at the outer periphery of the cover 30, i.e., the area near the sidewall 11. The thickness of the thinning region 31 is less than the thickness of other parts of the cover 30, and its specific thickness value needs to be determined according to the welding process and material properties. The thinning region 31 can be of uniform thickness or unequal thickness, and this embodiment is not limited to this. The forming method of the thinning region 31 is also not limited; for example, it can be formed by various methods such as upsetting and cutting.

[0048] Please see Figure 3 The thinning region 31 is recessed towards the electrode assembly 20 to form a first groove 311. The cover 30, sidewall 11 and current collector 40 are welded together to form a weld mark 50, which is located in the first groove 311. The shape of the first groove 311 matches the shape of the thinning region 31. For example, the annular thinning region 31 corresponds to the annular first groove 311.

[0049] It should be noted that the first groove 311 may only be provided at the position where the cover 30, the side wall 11 and the flow collecting member 30 need to be welded together, while other positions where only the cover 30 and the side wall 11 need to be welded together or where neither of them needs to be welded together may not have the thinning area 31, that is, the first groove 311 is not provided, that is, the first groove 311 only exists in a local position in the circumferential direction of the outer peripheral area of ​​the cover 30.

[0050] It should be noted that the thinning region 31 is a continuous or discontinuously distributed area formed on the cover 30, and the overall thickness of the thinning region 31 is smaller than the thickness of the cover 30. The first groove 311 can be equivalent to the thinning region 31 or can be formed on a local location of the thinning region 31 through a secondary molding process. The thickness of the first groove 311 can be smaller than that of other areas of the thinning region 31 to further reduce the thickness at the welding position. Therefore, the thinning region 31 can be a local location of the cover 30, and the first groove 311 can also be formed on a local location of the thinning region 31. In one embodiment, as... Figure 8 and Figure 9 As shown, the thinning area 31 is distributed in a local arc shape around the cover 30 in a circumferential direction, while the first groove 311 is located at a specific local position of the thinning area 31.

[0051] It should be noted that, provided that the weld mark 50 formed after welding the cover 30, side wall 11 and current collecting component 40 is located within the first groove 311, the welding method between the cover 30, side wall 11 and current collecting component 40 is not limited. For example, the thinning area 31 of the cover 30 can be welded to both the side wall 11 and the current collecting component 40 through welds, or the thinning area 31 of the cover 30 can be welded to the current collecting component 40 through welds, and the thinning area 31 of the cover 30 can be welded to the side wall 11 butt welds, etc.

[0052] This invention features a locally thinned area 31 on the cover 30, with the current collector 40 and sidewall 11 both in contact with and welded to this thinned area 31. This design offers several advantages. First, in terms of welding process, the thinned area 31 reduces the material thickness of the cover 30 at the welding area, thereby reducing the energy required for welding, mitigating defects such as bursts and spatter caused by high-energy welding, and improving welding yield. Simultaneously, the reduced welding heat also shrinks the heat-affected zone, reducing thermal damage to the internal electrode assembly 20 and lowering the risk of internal short circuits due to heat, thus improving the safety performance of the single-cell battery 100. Second, regarding structural strength and safety, the locally thinned design of the cover 30 ensures overall strength while optimizing the matching of the welding area, preventing a decrease in structural strength due to overall thinning, and thus ensuring the voltage withstand performance of the single-cell battery 100.

[0053] Furthermore, regarding the control and assembly compatibility of the weld pool 51, since the thinning area 31 is recessed towards the electrode assembly 20 to form a first groove 311, and the solder mark 50 is located within the first groove 311, the first groove 311 can constrain the weld pool 51, preventing it from spreading and thus improving the consistency of welding quality. Moreover, since the first groove 311 can accommodate the solder mark 50, it helps ensure the flatness of the end face of the cover 30, preventing the height of the solder mark 50 from affecting the assembly compatibility of the single battery cell 100, and facilitating subsequent module integration.

[0054] Please see Figure 3 In one embodiment of the present invention, the cover 30 further includes a central region 32, a first groove 311 surrounding the outer periphery of the central region 32, and the thinning region 31 on the side near the electrode assembly 20 is flush with the side of the central region 32 near the electrode assembly 20. Specifically, the side of the thinning region 31 near the electrode assembly 20 includes a first plane 313, and the side of the central region 32 near the electrode assembly 20 includes a second plane 321. The first plane 313 is disposed around the outer periphery of the second plane 321 and connected to the second plane 321, and the first plane 313 and the second plane 321 are in the same plane.

[0055] Since the current collector 40 inevitably deforms after welding with the electrode assembly 20, this may lead to positioning errors when the current collector 40 contacts the cover 30. The structural design in the above embodiment ensures that the side of the cover 30 facing the electrode assembly 20 is entirely planar, eliminating any axial height difference between the thinning region 31 and the central region 32. This design facilitates positioning contact between the current collector 40 and the cover 30, reduces the accumulation of errors caused by height differences, and thus improves the contact accuracy between the current collector 40 and the thinning region 31, reducing fitting errors.

[0056] Of course, in other embodiments, please refer to Figure 7 The thinning region 31 also includes a second groove 312 on the side facing the electrode assembly 20. The projection of the second groove 312 in the thickness direction of the cover 30 overlaps with the projection of the first groove 311. The current collector contacts the surface of the second groove 312 facing the electrode assembly 20. This further achieves the thinning of the cover 30 in the welding area.

[0057] Please see Figure 4 In one embodiment of this utility model, along the radial direction of the cover 30, the thinning region 31 is abutted against the inner wall of the sidewall 11, and the side of the first groove 311 facing the sidewall 11 is open, with the end face of the sidewall 11 near the opening 12 flush with the bottom wall of the first groove 311. Specifically, the sidewall 11 near the opening 12 includes a first end face 112, and the first groove 311 includes a groove bottom wall 3111. Along the radial direction of the cover 30, the side of the groove bottom wall 3111 away from the central region 32 is abutted against the inner wall of the sidewall 11. The surface of the groove bottom wall 3111 away from the electrode assembly 20 is flush with the first end face 112. The side of the central region 32 away from the electrode assembly 20 includes a top surface 322, which is higher than the surface of the groove bottom wall 3111 away from the electrode assembly 20. It should be noted that the top surface 322 refers to the surface on the cover 30 with the largest distance from the electrode assembly 20 along the thickness direction of the cover 30.

[0058] This design ensures that the height of the first end face 112 of the sidewall 11 is always lower than the height of the top surface 322 of the central region 32 of the cover 30. This not only ensures that the weld mark 50 can be accommodated within the first groove 311, but also avoids interference between the sidewall 11 and the welding head during the welding process. It also makes it easier for the welding head to act on the welding position in the vertical direction, thereby improving welding efficiency and ensuring welding quality.

[0059] Please see Figure 3In one embodiment of this utility model, along the radial direction of the cover 30, the thinned area 31 is abutted against the inner wall of the sidewall 11. The side of the first groove 311 facing the sidewall 11 is open. The sidewall 11 near the opening 12 has a first end face 112, which is higher than the bottom wall of the first groove 311 but not higher than the top surface 322 of the central region 32. Specifically, the first groove 311 includes a groove bottom wall 3111. Along the radial direction of the cover 30, the side of the groove bottom wall 3111 away from the central region 32 is abutted against the inner wall of the sidewall 11. The first end face 112 is higher than the surface of the groove bottom wall 3111 facing away from the electrode assembly 20 but not higher than the top surface 322. This design has two advantages. First, since the height of the first end face 112 of the sidewall 11 is not higher than the height of the top surface 322 of the central region 32, it effectively avoids interference between the sidewall 11 and the top mounting plane of the cover 30, ensuring the flatness and assembly compatibility of the top of the cover 30. Second, since the sidewall 11 can seal the opening of the first groove 311, it can better constrain the weld pool 51 during welding, preventing the weld pool 51 from spreading and overflowing at the joint between the thinning zone 31 and the sidewall 11, thus improving the stability of the welding quality between the thinning zone 31 and the sidewall 11.

[0060] Please see Figure 5 In one embodiment of this utility model, the current collecting member 40 includes a body portion 42 and welding pins 43. One end of the welding pin 43 is connected to the body portion 42, and the other end of the welding pin 43 extends toward the cover 30 and contacts the thinning region 31. The welding pin 43 can be a ring structure surrounding the outer periphery of the body portion 42, or it can be multiple separate structures spaced apart on the outer periphery of the body portion 42. The specific structural form needs to be determined according to the current conducting performance and welding strength requirements of the current collecting member 40.

[0061] The welding pin 43 has a first side surface 431, and the side wall 11 has a first end face 112 near the opening 12. Along the thickness direction of the cover 30, the first side surface 431 and the first end face 112 are flush to form an overlapping plane 41. The overlapping plane 41 is a toroidal structure and is approximately coaxial with the cover 30. The thinning area 31 at least partially overlaps the overlapping plane 41. By setting the overlapping plane 41, on the one hand, the overlapping plane 41 can provide axial positioning for the cover 30, ensuring the accuracy and consistency of the cover 30's installation position. On the other hand, since the thinning area 31 at least partially overlaps the overlapping plane 41, the thinning area 31, the current collector 40, and the side wall 11 form an overlapping structure in the welding area, thereby enabling through welding between the three. This welding method can simultaneously weld the cover 30, the current collector 40, and the side wall 11 in a single welding process, thereby improving welding efficiency and reducing welding costs.

[0062] Although there are multiple molding methods for the thinning zone 31, please refer to [link / reference]. Figure 5 In one embodiment of this utility model, the thinning region 31 is formed by a thinning process, and at least a portion of the surface of the first groove 311 has an anti-corrosion layer. The thinning process achieves uniform material thickness reduction and also reduces cracks and stress concentrations generated during the forming process. The anti-corrosion layer can be a nickel plating layer, applied to the groove surface via electroplating or chemical plating. Alternatively, it can be an anodic oxide layer, formed by electrolytic oxidation to create a dense oxide film. By providing an anti-corrosion layer in the thinning region 31, the probability of corrosion in the welding area of ​​the cover 30 can be reduced, improving the connection strength of the welding area during long-term use of the single battery cell 100.

[0063] In one embodiment of this utility model, the thinning area 31 is formed by a thinning process, and the cover 30 is subjected to nickel plating for corrosion protection before the thinning area 31 is formed. This overall nickel plating treatment ensures that not only are all surfaces of the thinning area 31 covered by the plating layer after forming, but also that other surfaces of the cover 30 are covered by the plating layer, thereby improving the overall corrosion resistance of the cover 30.

[0064] In one embodiment of this invention, the weld pool 51 of the solder mark 50 comprises nickel. The source of nickel in the weld pool 51 can be varied. For example, nickel can be introduced onto the surface of the thinned region 31 by nickel plating for corrosion protection, thereby ensuring that the weld pool 51 contains nickel after welding. Alternatively, nickel-based welding wire can be used during welding; the melting of the welding wire will also introduce nickel into the composition of the weld pool 51.

[0065] In this invention, by including nickel in the composition of the weld pool 51, on the one hand, the introduction of nickel into the weld pool 51 can effectively improve the wettability of the weld pool 51 and reduce the surface tension of the liquid metal, thereby reducing the incidence of defects such as incomplete welds and cold welds, and thus improving the forming quality of the weld mark 50. On the other hand, the introduction of nickel into the weld pool 51 can also increase the hardness and tensile strength of the weld mark 50, thereby improving the weld connection strength between the cover 30 and the side wall 11 and the current collector 40. In addition, the nickel plating layer can also play a certain role in heat insulation during the welding process, which helps to reduce the impact of welding heat input on the substrate, thereby reducing the range of the heat-affected zone and reducing the welding deformation generated in the welding area.

[0066] In one embodiment of this utility model, the cover 30 is made of steel, such as carbon steel or stainless steel. Steel has higher weld strength at the same thickness, and its welding difficulty is relatively low, with a more mature welding process. Of course, without considering the thickness requirement of the cover 30, the cover 30 can also be made of aluminum alloy or other composite materials that meet the requirements for weld strength and structural strength. To meet the structural strength requirements of the cover 30, the thickness of the central region 32 of the cover 30 is T2, and 0.2mm ≤ T2 ≤ 0.95mm. For example, T2 can be 0.2mm, 0.5mm, or 0.95mm. Preferably, 0.3mm ≤ T2 ≤ 0.6mm, and T1 can be 0.3mm, 0.45mm, or 0.6mm.

[0067] Please see Figure 4 In one embodiment of this utility model, a stepped portion 111 is provided on the inner wall of the sidewall 11, and the stepped portion 111 has a supporting surface 1111. Along the thickness direction of the cover 30, the welding pin 43 is at least partially clamped between the supporting surface 1111 and the thinning region 31. Specifically, the supporting surface 1111 is an annular structure that is substantially coaxial with the cover 30. The welding pin 43 is at least partially overlapped on the supporting surface 1111, and the surface of the thinning region 31 facing the electrode assembly 20 is pressed against the welding pin 43, thereby achieving that the welding pin 43 is clamped between the supporting surface 1111 and the thinning region 31.

[0068] This design improves the positioning accuracy between the welding pin 43 and the sidewall 11 and the thinned area 31, thereby enhancing welding precision. Furthermore, during penetration welding of the thinned area 31, the stepped portion 111 melts upon heating, promoting fusion between the sidewall 11 and the thinned area 31 and increasing the welding strength between them. Additionally, the stepped portion 111 acts as a physical barrier, effectively preventing weld slag from falling into the housing 10 during penetration, thus reducing the risk of foreign matter contamination of the electrode assembly 20.

[0069] Please see Figure 5 Furthermore, in one embodiment of this utility model, the weld pool 51 of the weld mark 50 is at least partially formed inside the stepped portion 111. This arrangement ensures that the thinned area 31 can be welded through during the welding process, thereby enabling through-welding between the welding pin 43, the thinned area 31, and the sidewall 11. This allows for simultaneous welding of the cover 30, the current collector 40, and the sidewall 11 in a single welding operation, reducing welding steps and improving welding efficiency. Moreover, compared to other welding methods, the weld mark 50 formed by through-welding can have higher welding strength and sealing performance, making it easier to meet the welding connection requirements between the cover 30, the sidewall 11, and the current collector 40.

[0070] Please see Figure 5 In one embodiment of this utility model, the weld pool 51 of the solder stamp 50 penetrates the thinning region 31 and extends into the interior of the current collector 40. Specifically, the weld pool 51 extends into the interior of the welding pin 43. This ensures that a through-weld is achieved between the current collector 40 and the thinning region 31, thereby ensuring the weld strength between the current collector 40 and the cover 30. In another embodiment, the weld pool 51 of the solder stamp 50 penetrates the thinning region 31 and extends into the interior of the sidewall 11. Specifically, the weld pool 51 may extend into the interior of the sidewall 11 by penetrating the first end face 112, or it may extend into the interior of the sidewall 11 by penetrating the inner wall of the sidewall 11, or it may partially penetrate the first end face 112 and partially penetrate the inner wall of the sidewall 11. This ensures that a through-weld is achieved between the thinning region 31 and the sidewall 11, thereby ensuring the weld strength between the cover 30 and the sidewall 11. In other embodiments, the weld pool 51 may extend partially into the interior of the flow collector 40 and partially into the interior of the sidewall 11 after penetrating the thinning zone 31. This ensures that the flow collector 40, the cover 30, and the sidewall 11 can be welded together, thereby enabling simultaneous welding of the cover 30, the flow collector 40, and the sidewall 11 in a single welding operation. This reduces welding steps and improves welding efficiency.

[0071] Please see Figure 4 In one embodiment of this utility model, the radial width of the support surface 1111 is W1, and the thickness of the side wall 11 at the opening 12 is T5, where 0.05mm ≤ W1 ≤ T5 mm, and 0.25mm ≤ T5 ≤ 0.6mm. For example, T5 can be 0.25mm, 0.425mm, or 0.6mm, etc. It should be noted that the thickness T5 of the side wall 11 at the opening 12 refers to the thickness of the side wall 11 where the step portion 111 is not provided. This arrangement ensures that the support surface 1111 has sufficient width to provide stable and reliable support for the welding pins 43 and the thinning area 31; and also ensures that the side wall 11 at the step portion 111 area has sufficient material thickness to ensure the overall structural strength of the housing 10.

[0072] Optionally, in one embodiment, 0.05mm ≤ W1 ≤ 0.4mm. For example, W1 can be 0.05mm, 0.2mm, or 0.4mm, etc. 0.25mm ≤ T5 ≤ 0.6mm. For example, T5 can be 0.25mm, 0.425mm, or 0.6mm, etc. Preferably, in another embodiment, 0.1mm ≤ W1 ≤ 0.3mm. For example, W1 can be 0.1mm, 0.2mm, or 0.3mm, etc. 0.25mm ≤ T5 ≤ 0.45mm. For example, T5 can be 0.25mm, 0.35mm, or 0.45mm, etc.

[0073] Please see Figure 4 In one embodiment of this utility model, the thickness of the welding pin 43 of the current collector 40 is T3, and the thickness of the body portion 42 is T4, wherein T3 ≥ T4, and 0.1mm ≤ T4 ≤ 0.5mm. For example, T4 can be 0.1mm, 0.3mm, or 0.5mm, etc. Preferably, 0.2mm ≤ T3 ≤ 0.4mm, for example, T3 can be 0.2mm, 0.3mm, or 0.4mm, etc. 0.2mm ≤ T4 ≤ 0.4mm, for example, T4 can be 0.2mm, 0.3mm, or 0.4mm, etc.

[0074] In this embodiment, the thickness T3 of the welding lead 43 is limited to 0.2mm ≤ T3 ≤ 0.4mm. This ensures the welding strength at the welding lead 43 position, reducing the probability of deformation and tearing at the welding lead 43 position during use of the single cell 100, thereby ensuring the stability of the welding connection. On the other hand, it also avoids increasing the difficulty of the welding process due to excessive thickness of the welding lead 43, and facilitates the welding operation between the welding lead 43 and the thinning area 31.

[0075] Meanwhile, by limiting the thickness T4 of the body portion 42 to satisfy 0.1mm≤T4≤0.5mm and T3≥T4, this setting avoids the body portion 42 from being too thick, thereby reducing the welding heat generated when it is welded to the electrode assembly 20, which is beneficial to improving the welding process and facilitating welding operations. On the other hand, it also ensures the structural strength of the body portion 42, reducing the problem of decreased electrical connection stability due to tearing during the operation of the single cell 100.

[0076] Please see Figure 4In one embodiment of this invention, based on the stepped portion 111 on the inner wall of the side wall 11, the welding pin 43 has at least one bent portion 44. The welding pin 43 includes a first bent segment 441 and a second bent segment 442 connected to each other. The second bent segment 442 is connected to the body portion 42 through the first bent segment 441. The second bent segment 442 is at least partially sandwiched between the support surface 1111 and the thinning region 31, and the second bent segment 442 is parallel to the surface of the cover 30 facing the electrode assembly 20. The end face of the second bent segment 442 is perpendicular to the inner wall of the side wall 11. Specifically, along the thickness direction of the cover 30, the side of the second bent segment 442 facing the cover 30 has a second end face 4421, and the second end face 4421 is perpendicular to the inner wall of the side wall 11. The depth of the first groove 311 is T1, and 0.05mm≤T1≤0.5mm. For example, T1 can be 0.05mm, 0.25mm, or 0.5mm, etc. Preferably, 0.1mm≤T1≤0.3mm.

[0077] It should be noted that the bending structure between the first bending segment 441 and the second bending segment 442 is not limited. For example, the first bending segment 441 can be bent perpendicularly to the second bending segment 442, or it can be bent at an angle relative to the second bending segment 442. Of course, the first bending segment 441 can also be designed as an arc bend or other complex shapes, depending on the size of the installation space and the flow guiding performance requirements of the flow collecting component 40. Optionally, in this embodiment, the first bending segment 441 is bent approximately perpendicularly to the second bending segment 442.

[0078] Of course, in other embodiments, the welding pin 43 may also be provided with two or more bends 44, and the multiple bends 44 may be in various bending structures such as Z-shaped bends and wavy bends.

[0079] By providing a bend 44 on the welding pin 43, the bend 44 can act as a stress buffer through its own elastic deformation. On the one hand, it can release the welding stress generated when the welding pin 43 is welded to the thinning area 31, reducing the transmission of welding stress to the body part 42, thereby reducing the probability of welding failure between the body part 42 and the electrode assembly 20. On the other hand, when the single cell 100 is subjected to external mechanical forces such as vibration and impact, the bend 44 can also release some of the deformation generated by the welding pin 43, which can further reduce the probability of electrical connection failure between the current collector 40 and the electrode assembly 20. In addition, since the height of the solder mark 50 at the welding position of the thinning area 31 is usually between 0.05 and 0.2 mm, in this embodiment, the depth T1 of the first groove 311 is limited to 0.05 mm ≤ T1 ≤ 0.5 mm. This ensures that the first groove 311 can accommodate most of the height of the solder mark 50, preventing the solder mark 50 from exceeding the height of the first groove 311.

[0080] Please see Figure 3 In one embodiment of this utility model, the width of the first groove 311 along the radial direction of the cover 30 is W2, and 0.1mm≤W2≤10mm. For example, W2 can be 0.1mm, 5mm, or 10mm, etc. By limiting the width W2 of the first groove 311 to 0.1mm≤W2≤10mm, it can be ensured that the width of the first groove 311 is neither too small, thus covering the width of the solder mark 50, nor too large, thus avoiding excessive weakening of the structural strength of the cover 30, thereby ensuring the overall structural strength of the cover 30.

[0081] Please see Figure 6In one embodiment of this utility model, along the radial direction of the cover 30, the thinned area 31 of the cover 30 is abutted against the inner wall of the sidewall 11. The end face of the sidewall 11 near the opening 12 protrudes from the top surface 322 of the cover 30, and the protrusion height is D1, where 0.05mm≤D1≤0.4mm. For example, D1 can be 0.05mm, 0.2mm, or 0.4mm, etc. Preferably, 0.1mm≤D1≤0.3mm, for example, D1 can be 0.1mm, 0.2mm, or 0.3mm, etc. Specifically, the sidewall 11 near the opening 12 includes a first end face 112, and the first groove 311 includes a groove bottom wall 3111. Along the radial direction of the cover 30, the side of the groove bottom wall 3111 away from the central region 32 is abutted against the inner wall of the sidewall 11. The top surface 322 of the cover 30 refers to the surface of the central region 32 facing away from the electrode assembly 20. This design serves two purposes. First, since the sidewall 11 can seal the open portion of the first groove 311, it effectively constrains the weld pool 51 during welding, preventing it from spreading and overflowing at the joint between the thinned area 31 and the sidewall 11. This, in turn, improves the stability of the welding quality between the thinned area 31 and the sidewall 11. Second, it ensures that the weld mark 50 and the top surface 322 of the cover 30 do not extend beyond the first end face 112, effectively preventing interference between the weld mark 50 and the top surface 322 and the assembly plane, thus ensuring the flatness and assembly compatibility of the first end face 112.

[0082] Please see Figure 10 In one embodiment of the battery pack 200 of this utility model, the battery pack 200 includes a housing 201 and at least one individual battery cell 100; the housing 201 includes a first housing portion 2011 and a second housing portion 2012, which cover each other to form an accommodating space, in which multiple individual batteries cell 100 are housed, and the multiple individual batteries cell 100 can be connected in series and / or in parallel. The battery pack 200 can be, for example, a battery module, a battery pack, etc.

[0083] Please see Figure 11In one example of the electronic device 300 of this utility model, the electronic device 300 includes a working part 310 and a battery pack 200. The working part 310 is electrically connected to the battery pack 200 to obtain electrical power. The working part 310 can be a unit component capable of obtaining electrical power from the battery pack 200 and performing corresponding work, such as a fan blade rotation unit, a vacuum cleaner suction unit, or a wheel drive unit in an electric vehicle. The electronic device 300 can be a vehicle, mobile phone, portable device, laptop computer, ship, spacecraft, electric toy, and power tool, etc. Vehicles can be gasoline-powered cars, natural gas-powered cars, or new energy vehicles. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. Spacecraft include airplanes, rockets, space shuttles, and spacecraft, etc. Electric toys include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. This utility model embodiment does not impose special limitations on the above-mentioned electronic device 300. In one embodiment of the electronic device 300 of this utility model, the electronic device 300 is a vehicle, the working part 310 is the vehicle body, and the battery pack 200 is fixedly installed on the vehicle body, thereby providing driving force for the vehicle to operate.

[0084] The above embodiments are merely illustrative of the principles and effects of this utility model and are not intended to limit the scope of this utility model. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of this utility model. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in this utility model should still be covered by the claims of this utility model.

Claims

1. A single-cell battery, characterized in that, include: A housing, the housing including sidewalls forming an opening; Electrode assemblies are installed inside the housing; A cover is provided to seal the opening and is welded and fixed to the side wall. A current collecting component is disposed between the cover and the electrode assembly, and the current collecting component is electrically connected to the current collecting part of the electrode assembly; Wherein, on the side of the cover body away from the electrode assembly, the cover body includes a thinning area, and the side of the thinning area away from the electrode assembly is recessed to form a first groove. The cover body, the side wall and the current collector are welded together to form a weld mark, and the weld mark is located in the first groove.

2. The single-cell battery according to claim 1, characterized in that, The cover also includes a central region, the first groove surrounds the outer periphery of the central region, and the side of the thinned area near the electrode assembly is flush with the side of the central region near the electrode assembly.

3. The single-cell battery according to claim 1, characterized in that, Along the radial direction of the cover, the thinning area is aligned with the inner wall of the sidewall. The first groove extends through the thinning area on the side facing the sidewall and forms an opening. The sidewall has a first end face near the opening. The first end face is flush with the bottom wall of the first groove, or the first end face is higher than the bottom wall of the first groove but not higher than the top surface of the cover.

4. The single-cell battery according to claim 1, characterized in that, The current collection component includes a body portion and a welding pin connected to the body portion and in contact with the thinning area. The welding pin has a first side surface, and the side wall near the opening has a first end face. The first side surface and the first end face are flush to form an overlapping plane, and the thinning area at least partially overlaps the overlapping plane.

5. The single-cell battery according to claim 1, characterized in that, The thinning zone is formed by a thinning process, and at least part of the surface of the first groove has an anti-corrosion layer; the cover is subjected to nickel plating anti-corrosion treatment before the thinning zone is formed, and the composition of the weld pool of the solder mark includes nickel.

6. The single-cell battery according to claim 1, characterized in that, The inner wall of the sidewall is provided with a stepped portion, the stepped portion having a supporting surface. Along the thickness direction of the cover, the current collecting member includes a main body and a welding pin connected to the main body and in contact with the thinning area. The welding pin is at least partially clamped between the supporting surface and the thinning area. The weld pool of the solder mark is at least partially formed inside the stepped portion. The radial width of the supporting surface is W1, the thickness at the opening of the sidewall is T5, and 0.05mm≤W1≤T5 mm, where 0.25mm≤T5≤0.6mm; the thickness of the welding pin is T3, the thickness of the main body is T4, where T3≥T4, and 0.1mm≤T4≤0.5mm.

7. The single-cell battery according to claim 6, characterized in that, The welding pin has at least one bend, and the welding pin includes a first bend segment and a second bend segment connected to each other. The second bend segment is connected to the body through the first bend segment. The second bend segment is parallel to the surface of the cover facing the electrode assembly, and the end face of the second bend segment is perpendicular to the inner wall of the sidewall. The depth of the first groove is T2, and 0.05mm≤T2≤0.5mm.

8. The single-cell battery according to claim 2, characterized in that, Along the radial direction of the cover, the thinned area of ​​the cover is abutted against the inner wall of the sidewall, and the end face of the sidewall near the opening protrudes from the end face of the central region away from the electrode assembly, and the protrusion height is D1, and 0.05mm≤D1≤0.4mm.

9. A battery pack, characterized in that, The single-cell battery includes any one of claims 1 to 8.

10. An electronic device, characterized in that, Includes the battery pack as described in claim 9.

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