A cylindrical battery and battery pack

Abstract

The utility model provides a kind of cylindrical battery and battery pack, cylindrical battery includes: shell, electrode assembly, sealing element and cover plate, shell includes accommodating cavity, the side wall of shell is enclosed to have opening, side wall is bent to form first recess near opening position, first recess has the recess opening of intercommunication accommodating space;Electrode assembly is accommodated in accommodating space;Cover plate includes the middle part being equipped with anti-explosion score and the edge portion being assembled in first recess;Sealing element covers edge portion and is located between edge portion and the inner surface of first recess;Cover plate includes the first surface being away from electrode assembly along thickness direction and the second surface being opposite to first surface, and the end surface being connected between first surface and second surface, end surface includes the first chamfer surface being connected with first surface;And / or end surface includes the second chamfer surface being connected with second surface.The utility model can improve the problem that anti-explosion score is damaged and abnormally opened due to stress concentration during sealing process.

Description

Technical Field

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

[0002] In the manufacturing of cylindrical batteries, mechanical pressing is currently one of the mainstream processes for assembling the cover plate and the casing. This process involves mechanically bending the sidewalls of the casing to press the seal tightly and cover the outer edge of the cover plate, thereby achieving a reliable seal at the casing opening. However, during the sidewall pressing process, the outer edge of the cover plate is subjected to both axial and radial compressive forces. This radial compressive force exacerbates stress concentration at the explosion-proof markings on the cover plate, potentially causing abnormal fracture of the explosion-proof markings and resulting in the failure of the explosion-proof function, thus affecting the safety performance and reliability of the cylindrical battery. Summary of the Invention

[0003] This invention provides a cylindrical battery and battery pack, which can improve the technical problem of abnormal fracture caused by stress on explosion-proof grooves.

[0004] This utility model provides a cylindrical battery, comprising: a casing, an electrode assembly, a sealing element, and a cover plate. The casing includes a sidewall, one end of which forms an opening. The casing provides a receiving space, and the sidewall includes an inner surface located within the receiving space. The sidewall is bent near the opening to form a first groove. The first groove has a groove opening communicating with the receiving space. Both the first groove and the groove opening are continuously distributed along the circumference of the cylindrical battery. A portion of the inner surface of the sidewall forms the inner surface of the first groove. The electrode assembly is received within the receiving space. The cover plate includes a central portion and a surrounding portion. The edge portion, which is located in the middle and fitted within the first groove, has explosion-proof grooves in the middle; the seal covers the edge portion and is located between the edge portion and the inner surface of the first groove; wherein, along the thickness direction of the cover plate, the cover plate includes a first surface away from the electrode assembly along the thickness direction and a second surface away from the first surface, and an end face connecting the first surface and the second surface, the end face including a first chamfered surface that contacts the first surface, the first chamfered surface being continuously distributed circumferentially; and / or the end face including a second chamfered surface that contacts the second surface, the second chamfered surface being continuously distributed circumferentially.

[0005] In one embodiment of the present invention, the end face includes only a first chamfered surface, which is a rounded corner surface. The two ends of the first chamfered surface are respectively connected to the first surface and the second surface. The height d1 of the first chamfered surface along the thickness direction is equal to the thickness D of the cover plate.

[0006] In one embodiment of the present invention, the end face includes a first chamfered surface, a second chamfered surface, and a connecting surface. The first chamfered surface is connected to the second chamfered surface through the connecting surface; the connecting surface is a vertical surface.

[0007] In one embodiment of the present invention, the end face includes a first chamfered surface, which is a rounded corner surface; the first groove includes a groove sidewall, a groove top wall, and a transition angle, the groove sidewall is disposed around the outer periphery of the edge portion, the groove top wall is disposed on the side of the cover plate away from the electrode assembly, and the groove top wall is connected to the groove sidewall through the transition angle; the transition angle is a rounded corner, and the radius of the transition angle is smaller than the radius of the first chamfered surface; on the cross section through the axis, along the line connecting the center of the transition angle and the center of the first chamfered surface, the projected profile of the transition angle is located within the projected profile of the first chamfered surface.

[0008] In one embodiment of the present invention, the end face includes only a first chamfered surface and a second chamfered surface, and the end of the first chamfered surface facing away from the first surface is connected to the end of the second chamfered surface facing away from the second surface.

[0009] In one embodiment of the present invention, the first chamfered surface and the second chamfered surface are rounded corner surfaces with equal radii, and the height d1 of the first chamfered surface along the thickness direction is equal to the height d2 of the second chamfered surface along the thickness direction. The thickness of the cover plate is D, and d1+d2=D.

[0010] In one embodiment of the present invention, along the axial direction of the shell, the height of the first chamfered surface is d1, the height of the second chamfered surface is d2, the thickness of the cover plate is D, and 0 < d1 + d2 < D, and d1 ≥ d2; along the radial direction of the shell, the width of the first chamfered surface is L1, the width of the second chamfered surface is L2, and L1 ≥ L2 > D.

[0011] In one embodiment of the present invention, the thickness of the cover plate is D, the width of the groove top wall along the radial direction of the shell is L3, and L3≥2D, the sealing element includes a first sealing part located between the groove top wall and the edge portion, the first sealing part has a first inner edge near the axis, the groove top wall has a second inner edge near the axis, the first inner edge is located on the side of the second inner edge near the axis; the thickness of the side wall is D1, the thickness of the cover plate is D, and 1≤D / D1≤2.

[0012] In one embodiment of the present invention, the first chamfered surface and / or the second chamfered surface are formed on the cover plate by one or two stamping processes.

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

[0014] The beneficial effects of this invention are as follows: Compared to structures without chamfered surfaces on the edge of the cover plate, this embodiment creates a pressure relief space between the edge and the seal by providing a first and / or second chamfered surface on the edge. During the mechanical sealing process (i.e., the formation of the first groove), this relief space prevents the seal at this location from being excessively compressed and deformed compared to other locations, thereby reducing the radial compression on the cover plate. This reduces the risk of increased stress concentration within the explosion-proof scoring area, preventing premature rupture of the explosion-proof scoring due to increased internal stress. Therefore, it reduces the risk of abnormal valve opening due to explosion-proof scoring, improving the explosion-proof reliability and long-term safety of the cylindrical battery. Attached Figure Description

[0015] 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.

[0016] In the attached diagram:

[0017] Figure 1 This is a cross-sectional view of the overall structure of a cylindrical battery provided in an embodiment of the present invention;

[0018] Figure 2 for Figure 1 Enlarged view of the central area;

[0019] Figure 3 for Figure 2 A schematic diagram of the embodiment shown in the image, without the seal and cover plate;

[0020] Figure 4 for Figure 2 The diagram shown is a schematic of the structure without the cover plate in the embodiment shown.

[0021] Figure 5 for Figure 2 A schematic diagram of the edge portion of the cover plate in the embodiment shown;

[0022] Figure 6 This is a schematic diagram of the electrode assembly in a cylindrical battery provided in one embodiment of the present invention;

[0023] Figure 7 This is a schematic diagram of the structure of a cover plate with a first chamfered surface on its edge, according to one embodiment of the present invention.

[0024] Figure 8 This is a schematic diagram of a structure in another embodiment of the present invention, showing that the edge of the cover plate is provided with a first chamfered surface;

[0025] Figure 9 This is a schematic diagram of a structure in another embodiment of the present invention, showing that the edge of the cover plate is provided with a second chamfered surface;

[0026] Figure 10 This is a schematic diagram of a structure in one embodiment of the present invention, showing that the edge of the cover plate is provided with both a first chamfered surface and a second chamfered surface.

[0027] Figure 11 This is a schematic diagram of a structure in another embodiment of the present invention, showing that the edge of the cover plate is provided with both a first chamfered surface and a second chamfered surface;

[0028] Figure 12 This is a schematic diagram of a structure in another embodiment of the present invention, showing that the edge of the cover plate is provided with both a first chamfered surface and a second chamfered surface;

[0029] Figure 13 This is a schematic diagram of a structure in another embodiment of the present invention, showing that the edge of the cover plate is provided with a first chamfered surface;

[0030] Figure 14 This is a schematic diagram of the structure of the cover plate having a first chamfered surface at its edge in another embodiment of the present invention;

[0031] Figure 15 This is a schematic diagram of a structure in one embodiment of the present invention, where both the first chamfered surface and the second chamfered surface are rounded corner surfaces and are connected to each other;

[0032] Figure 16 This is a schematic diagram of a structure in another embodiment of the present invention, showing that the edge of the cover plate is provided with both a first chamfered surface and a second chamfered surface;

[0033] Figure 17 This is a schematic diagram of the structure in one embodiment of the present invention, showing the inner edge of the sealing element extending beyond the inner edge of the top wall of the groove;

[0034] Figure 18 This is a schematic diagram of a structure in one embodiment of the present invention, where both the first chamfered surface and the second chamfered surface are rounded corners, and the heights of the first chamfered surface and the second chamfered surface are equal.

[0035] Figure 19 This is a schematic diagram of the structure of a battery pack provided in an embodiment of the present invention;

[0036] Figure 20 This is a schematic diagram of the structure of an electronic device provided in an embodiment of the present invention.

[0037] The attached figures are labeled as follows:

[0038] 100. Cylindrical battery; 10. Casing; 101. Receiving space; 102. Axis; 11. Side wall; 111. Inner side surface; 12. Opening; 13. First groove; 131. Groove side wall; 132. Groove top wall; 1321. Second inner edge; 133. Transition angle; 134. Groove opening; 135. Groove bottom wall; 14. Groove; 15. 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. 24. Second uncoated area; 25. Negative electrode tab; 30. Positive electrode tab; 31. Seal; 31. First sealing part; 311. First inner edge; 32. Second sealing part; 33. Third sealing part; 34. Second groove; 40. Cover plate; 401. First surface; 402. Second surface; 403. End face; 4031. First chamfered surface; 4032. Second chamfered surface; 4033. Connecting surface; 41. Explosion-proof groove; 42. Middle part; 43. Edge part; 200. Battery pack; 201. Housing; 2011. First housing part; 2012. Second housing part; 300. Electronic device; 310. Working part. Detailed Implementation

[0039] 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.

[0040] 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.

[0041] 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.

[0042] Please see Figures 1 to 20This invention provides a cylindrical battery 100 and a battery pack 200. The cylindrical battery 100 has a first chamfered surface 4031 and / or a second chamfered surface 4032 on the edge 43 of the cover plate 40 covered by the sealing member 30. This structural design can mitigate the axial and radial compressive forces on the edge of the cover plate 40 caused by the compression of the sealing member 30 during the mechanical sealing process. This reduces the risk of increased internal stress concentration caused by compression or stretching of the explosion-proof groove 41, thus preventing unexpected damage or premature opening of the explosion-proof groove 41 due to increased stress. Therefore, it reduces the probability of abnormal opening of the explosion-proof valve, ultimately improving the explosion-proof reliability and long-term safety of the cylindrical battery 100.

[0043] Please see Figure 1 The structure of the cylindrical battery 100 is further described, which includes: a housing 10, an electrode assembly 20, a seal 30, and a cover plate 40.

[0044] The housing 10 provides a receiving space 101 for accommodating the electrode assembly 20, electrolyte, and other components. The housing 10 can be open at one end or open at both ends. The specific dimensions of the housing 10 can be determined according to the specific dimensions of the electrode assembly 20, for example, to meet the specifications of large cylindrical batteries 100 such as 4680, 4695, and 46120. The housing 10 can be made of various materials, such as copper, iron, aluminum, steel, and aluminum alloy. To prevent the housing 10 from rusting during long-term use, a rust-preventive material, such as metallic nickel, can be plated on the surface of the housing 10.

[0045] The housing 10 has a cylindrical structure and includes an end wall 15 and a side wall 11 surrounding the end wall 15. The end wall 15 and the side wall 11 enclose a receiving space 101, which includes a closed end and an open end. Specifically, the end wall 15 forms a closed end, and the side wall 11 has an opening 12 at one end away from the end wall 15 to form an open end. The side wall 11 includes an inner surface 111 located within the receiving space 101.

[0046] Please see Figure 2 and Figure 3 Along the axial direction of the housing 10, the sidewall 11 is bent at a position near the opening 12 to form a first groove 13. The first groove 13 has a groove opening 134 that communicates with the receiving space 101. The first groove 13 and the groove opening 134 are continuously distributed along the circumference of the cylindrical battery 100. A portion of the inner surface 111 of the sidewall 11 forms the inner surface of the first groove 13.

[0047] Specifically, the first groove 13 is an annular groove structure circumferentially arranged around the housing 10. The first groove 13 includes a bottom wall 135, a side wall 131, and a top wall 132. The side wall 131 extends approximately along the axial direction of the housing 10. The bottom wall 135 and the top wall 132 are respectively connected to the two ends of the side wall 131 in the extending direction, and both are bent relative to the side wall 131 toward the axis 102 of the housing 10. The top wall 132 is located on the side of the side wall 131 facing the opening 12, and the bottom wall 135 is located on the side of the side wall 131 away from the opening 12. Along the radial direction of the housing 10, the side of the first groove 13 away from the side wall 131 forms a groove opening 134.

[0048] Please see Figure 3 In order to facilitate the formation of the first groove 13, a groove 14 recessed into the receiving space 101 is provided on the side wall 11 near the opening 12. The groove 14 is supported on the side of the first groove 13 away from the opening 12, and the groove wall of the groove 14 facing the opening 12 forms the bottom wall 135 of the first groove 13.

[0049] Specifically, the groove 14 is a recessed structure formed by the sidewall 11 being squeezed and deformed towards the interior of the housing 10 under the action of external mechanical force. The groove 14 can be formed by stamping the sidewall 11 with a forming die, or it can be formed by rolling the sidewall 11 with a grooving tool, as long as the groove 14 on the sidewall 11 is a recessed structure arranged in the circumferential direction of the sidewall 11. The cross-sectional shape of the groove 14 can be any shape that meets the usage requirements, such as rectangular, square, or trapezoidal.

[0050] Please see Figure 1 The electrode assembly 20 is housed within the housing space 101. The housing space 101 may contain one or more electrode assemblies 20. The electrode assembly 20 is the component in the cylindrical battery 100 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 an 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 external electrical connectors. The current collector can also be a full tab structure, that is, the entire positive / negative current collector is turned into tabs, and the current collector is fully connected to the casing 10 or current collector component of the cylindrical battery 100 through the current collector.

[0051] Please see Figure 6Optionally, 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.

[0052] 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 one end of the cylindrical battery 100 in the height direction to the outside of the separator 22 and is bent toward the axis 102 of the housing 10 to form a stacked positive electrode tab 25, i.e., a positive current collector.

[0053] 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 cylindrical battery 100 in the height direction to the outside of the separator 22 and is bent toward the axis 102 of the housing 10 to form a stacked negative electrode tab 24, i.e., a negative electrode current collector.

[0054] 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 cylindrical battery 100 as an example, the positive current collector 211 can be made of aluminum, and the positive active material layer includes 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 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.

[0055] Please see Figure 1 and Figure 6Furthermore, in this invention, the positive electrode tab 25 faces the end wall 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 15 and is electrically connected to the electrode terminal disposed at the end wall 15, 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. The housing 10 can be directly electrically connected to the negative electrode tab 24, or it can be electrically connected to the negative electrode tab 24 through a conductive component such as a current collector. 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.

[0056] Please see Figures 2 to 5 The seal 30 is at least partially accommodated within the first groove 13, and the seal 30 has a second groove 34. The opening direction of the second groove 34 is consistent with the direction of the groove opening 134 of the first groove 13. The cover plate 40 includes a central portion 42 and an edge portion 43, and the central portion 42 is provided with an explosion-proof notch 41. The explosion-proof notch 41 is the weakest point in the structure of the entire cover plate 40. When the working pressure inside the housing 10 reaches the design threshold, the explosion-proof notch 41 will rupture first, forming a directional pressure relief channel, thereby preventing the cylindrical battery 100 from exploding.

[0057] Edge portion 43 surrounds the outer periphery of central portion 42 and is fitted within first groove 13. Seal 30 covers edge portion 43 and is located between edge portion 43 and inner surface of first groove 13. Specifically, edge portion 43 is fitted within second groove 34, and edge portion 43 abuts against inner surface of second groove 34, thereby achieving contact between outer surface of second groove 34 and inner surface of first groove 13.

[0058] In the actual production process of the cylindrical battery 100, before the mechanical sealing process begins, the aforementioned groove 14 needs to be formed at the open end of the casing 10. The seal 30, with an approximately L-shaped cross-section, is pre-installed on the edge 43 of the cover plate 40. The cover plate 40, together with the seal 30, is assembled to the opening 12 of the casing 10, and the cover plate 40 and seal 30 are positioned on the sidewall 11 of the groove 14 facing the opening 12. Subsequently, the cover plate 40 is assembled at the opening 12 of the casing 10, so that the edge 43 of the cover plate 40 is pressed against the seal 30. Finally, the sidewall 11 at the opening 12 is mechanically sealed. During this process, the material of the sidewall 11 bends towards the axis 102 of the casing 10, thereby forming a first groove 13 for locking and fixing the seal 30 and the cover plate 40. At the same time, the sealing element 30 is bent together with the side wall 11 to completely cover the edge 43 of the cover plate 40, thereby achieving a sealed fixation of the cover plate 40 in the first groove 13.

[0059] Please see Figure 2 and Figure 5 Along the thickness direction of the cover plate 40, the cover plate 40 includes a first surface 401 facing away from the electrode assembly 20 and a second surface 402 facing away from the first surface 401, and an end face 403 connecting the first surface 401 and the second surface 402. In one embodiment, please refer to... Figure 7 The end face 403 includes a first chamfered surface 4031 that contacts the first surface 401. The first chamfered surface 4031 is continuously distributed along the circumference of the housing 10, that is, the first chamfered surface 4031 is a ring-shaped structure surrounding the axis 102 of the housing 10. The first chamfered surface 4031 can be a rounded corner surface (e.g., Figure 7 (as shown), oblique surface (such as) Figure 8 (as shown) or other shapes, etc., are not limited in this embodiment. It should be noted that, in this embodiment, the end of the first chamfered surface 4031 away from the first surface 401 may be connected to the second surface 402 or may not be connected to the second surface 402.

[0060] Please see Figure 9 In another embodiment, the end face 403 includes a second chamfered surface 4032 that contacts the second surface 402, and the second chamfered surface 4032 is continuously distributed along the circumference of the housing 10. That is, the second chamfered surface 4032 is a toroidal structure surrounding the axis 102 of the housing 10. The second chamfered surface 4032 can be a rounded surface, an oblique surface, or other shapes, etc., and this embodiment is not limited to this. It should be noted that in this embodiment, the end of the second chamfered surface 4032 away from the second surface 402 can be connected to the first surface 401 or not connected to the first surface 401.

[0061] Please see Figures 10 to 12 In other embodiments, the end face 403 includes a first chamfered surface 4031 and a second chamfered surface 4032. The first chamfered surface 4031 is connected to the first surface 401, and the second chamfered surface 4032 is connected to the second surface 402. The first chamfered surface 4031 may be connected to the second chamfered surface 4032, such as... Figure 11 As shown. Alternatively, it can be not connected to the second chamfered surface 4032, as shown. Figure 10 As shown.

[0062] Compared to a structure where the end face 403 of the edge portion 43 of the cover plate 40 does not have a chamfered surface, this embodiment provides a first chamfered surface 4031 and / or a second chamfered surface 4032 on the end face 403 of the edge portion 43. This creates an additional residual space between the end face 403 of the edge portion 43 and the seal 30. This residual space can accommodate part of the elastic deformation of the seal 30 during the mechanical sealing process (i.e., the forming of the first groove 13), thereby releasing part of the radial compressive force of the seal 30 on the edge portion 43 of the cover plate 40 and reducing the assembly stress generated inside the cover plate 40. As the assembly stress inside the cover plate 40 decreases, the probability of increased internal stress concentration due to compression or stretching in the explosion-proof groove 41 area decreases, thus reducing the probability of the explosion-proof groove 41 prematurely breaking open due to its own internal stress increasing to the breaking limit. Therefore, it can ensure the normal activation of the explosion-proof groove 41 under set conditions, reduce the probability of abnormal opening, and improve the explosion-proof reliability and long-term safety of the cylindrical battery 100. Furthermore, the provision of the first chamfered surface 4031 and / or the second chamfered surface 4032 increases the contact area between the seal 30 and the end face 403 of the edge portion 43, making the distribution of the compressive force on the edge portion 43 more uniform. This can further alleviate the stress concentration phenomenon at the edge portion 43 of the cover plate 40, thereby further reducing the probability of stress increase in the area of ​​the explosion-proof groove 41.

[0063] Please see Figure 13 and Figure 14 In one embodiment of this utility model, the end face 403 includes only a first chamfered surface 4031, which is a rounded corner surface. One end of the first chamfered surface 4031 is connected to the first surface 401, and the other end is connected to the second surface 402. The height d1 of the first chamfered surface 4031 along the thickness direction of the cover plate 40 is equal to the thickness D of the cover plate 40. The connection method between the first chamfered surface 4031 and the first surface 401 and the second surface 402 is not limited; for example, ... Figure 13 As shown, the first chamfered surface 4031 can be tangentially connected to the first surface 401. For example... Figure 14 As shown, the first chamfered surface 4031 can also be tangentially connected to the second surface 402.

[0064] In this embodiment, the first chamfered surface 4031 adopts a rounded corner design, and its two ends are respectively connected to the first surface 401 and the second surface 402. This design structure has beneficial effects on both manufacturing process and structural performance. In terms of manufacturing process, the rounded corner surface is easy to form in one step by stamping or die cutting. At the same time, replacing multiple chamfered surface schemes with a single complete rounded corner surface structure can simplify the processing steps of the chamfered surface on the cover plate 40, saving processing steps and costs. In terms of structural performance, the smooth and continuous rounded corner transition can better eliminate the stress concentration caused by sharp corners. During the mechanical sealing process, this design can provide a more ideal deformation space for the seal 30, making the compressive stress transmitted to the edge 43 of the cover plate 40 more uniformly distributed, thereby further reducing the transmission of assembly stress to the explosion-proof groove 41 area.

[0065] Please see Figure 2 and Figure 5 In one embodiment of this utility model, the end face 403 includes a first chamfered surface 4031, a second chamfered surface 4032, and a connecting surface 4033. The first chamfered surface 4031 is connected to the second chamfered surface 4032 through the connecting surface 4033, and the connecting surface 4033 is a vertical surface perpendicular to the first surface 401. Specifically, the extending direction of the connecting surface 4033 is basically consistent with the thickness direction of the cover plate 40. The end of the connecting surface 4033 facing the first surface 401 is connected to the first chamfered surface 4031, and the end of the connecting surface 4033 facing the second surface 402 is connected to the second chamfered surface 4032.

[0066] In this embodiment, the end face 403 of the edge portion 43 of the cover plate 40 adopts a combined design: a connecting surface 4033 in the middle, and the upper and lower ends are transitioned by a first chamfered surface 4031 and a second chamfered surface 4032. This structure, while utilizing the buffering and stress-dispersing functions of the chamfered surfaces on both sides, enhances the overall rigidity of the edge portion 43 by utilizing the connecting surface 4033 in the middle. During the mechanical sealing process, the connecting surface 4033 can effectively resist the deformation caused by the extrusion of the sealing element 30, so that the edge portion 43 of the cover plate 40 can still maintain its shape stability and accurate position under high pressure, thereby avoiding problems such as poor sealing or improper installation caused by crushing or skewing of the edge portion 43. In addition, this combined end face structure can also avoid sharp edges with a large radial width in the edge portion 43, thereby reducing the angularity of the cover plate 40 at the edge portion 43, which helps to ensure the structural strength of the cover plate 40 at the edge portion 43, thus ensuring the overall mechanical strength of the cylindrical battery 100.

[0067] Please see Figure 2In one embodiment of this utility model, the end face 403 includes a first chamfered surface 4031, which is a rounded corner surface. The first groove 13 includes a groove sidewall 131 and a groove top wall 132 as described in the previous embodiment. The groove sidewall 131 is disposed around the outer periphery of the edge portion 43, and the groove top wall 132 is disposed on the side of the cover plate 40 away from the electrode assembly 20. The groove top wall 132 and the groove sidewall 131 are bent to form a transition angle 133. The groove top wall 132 is connected to the groove sidewall 131 through the transition angle 133. The transition angle 133 is a rounded corner, and the radius of the transition angle 133 is smaller than the radius of the first chamfered surface 4031. On a cross section passing through the axis 102 of the housing 10, along the line connecting the center of the transition angle 133 and the center of the first chamfered surface 4031, as shown... Figure 2 As shown in the X-axis direction, the projected profile of the transition angle 133 lies within the projected profile of the first chamfered surface 4031. The transition angle 133 can be coaxial with the first chamfered surface 4031 or not; this embodiment is not limited to this.

[0068] In this embodiment, by positioning the projected profile of the transition angle 133 within the projected profile of the first chamfered surface 4031 on the cross-section of the axis 102 of the housing 10, the first chamfered surface 4031 effectively adapts to and covers the transition angle 133 in terms of both angle and profile. This design allows the first chamfered surface 4031 to effectively receive and guide the compressive force transmitted from the transition angle 133 during the mechanical sealing process, forming a stable stress transmission path. This improves the stability and reliability of the stress relief effect at the location of the first chamfered surface 4031, and more effectively reduces the assembly stress transmitted to the explosion-proof notch 41 area, further ensuring the normal use of the explosion-proof notch 41.

[0069] Please see Figure 11 and Figure 15 In one embodiment of this utility model, the end face 403 includes only a first chamfered surface 4031 and a second chamfered surface 4032, and the end of the first chamfered surface 4031 facing away from the first surface 401 is connected to the end of the second chamfered surface 4032 facing away from the second surface 402. The first chamfered surface 4031 and the second chamfered surface 4032 can both be rounded surfaces, or one of them can be a rounded surface and the other a beveled surface, or both can be beveled surfaces.

[0070] In this embodiment, by directly connecting the first chamfered surface 4031 and the second chamfered surface 4032, a continuous and complete stress guiding interface can be formed on the entire end face 403 connecting the first surface 401 and the second surface 402. During the mechanical sealing process, this structure can effectively buffer and uniformly distribute the bidirectional compressive force (from top to bottom and from bottom to top) generated by the seal 30. Compared to a single chamfered surface structure, this continuous chamfered surface structure can better alleviate the stress concentration phenomenon generated on the edge 43 of the cover plate 40, allowing the assembly stress generated during the forming of the first groove 13 to be transmitted and released more smoothly along the thickness direction of the cover plate 40, thereby reducing the residual stress transmitted to the explosion-proof notch 41 area. Simultaneously, this structure can also increase the contact area between the seal 30 and the edge 43 of the cover plate 40, improving the uniformity of the sealing pressure distribution, thus further enhancing the long-term stability and reliability of the seal while ensuring the functional integrity of the explosion-proof notch 41.

[0071] Please see Figure 15 and Figure 18 In one embodiment of this utility model, the end face 403 includes a first chamfered surface 4031 and a second chamfered surface 4032, and the first chamfered surface 4031 and the second chamfered surface 4032 are connected. Both the first chamfered surface 4031 and the second chamfered surface 4032 are rounded corners, and the radius of the first chamfered surface 4031 and the radius of the second chamfered surface 4032 are equal. The height d1 of the first chamfered surface 4031 along the thickness direction of the cover plate is equal to the height d2 of the second chamfered surface 4032 along the thickness direction of the cover plate. The thickness of the cover plate is D, and d1 + d2 = D.

[0072] In this embodiment, when both the first chamfered surface 4031 and the second chamfered surface 4032 are rounded surfaces, the first chamfered surface 4031 is preferably tangentially connected to the first surface 401, and the second chamfered surface 4032 is also preferably tangentially connected to the second surface 402. This tangential connection ensures a smooth, edge-free transition between the first surface 401 and the first chamfered surface 4031, and between the second surface 402 and the second chamfered surface 4032. During the mechanical sealing process, when the compressive stress generated at the first groove 13 acts on the edge 43 of the cover plate 40, this smooth transition can improve the stress concentration problem caused by geometric abrupt changes, allowing the stress to be more smoothly introduced into the chamfered surface area and evenly distributed, thereby achieving a better stress guidance and buffering effect. Of course, in other embodiments, if the above-mentioned beneficial effects are not considered, the first chamfered surface 4031 and the first surface 401, and the second chamfered surface 4032 and the second surface 402, can also be connected in a non-tangential manner.

[0073] In the above embodiments, since the first chamfered surface 4031 and the second chamfered surface 4032 are rounded surfaces with equal radii, and the first chamfered surface 4031 and the second chamfered surface 4032 are coaxially arranged, this arrangement allows the first chamfered surface 4031 and the second chamfered surface 4032 to connect and form a smooth, continuous, and symmetrical complete arc surface. During the mechanical sealing process, this complete arc surface can provide an ideal stress transmission path without bends or sharp corners for compressive forces from multiple directions. Stress can be guided and dispersed more smoothly along this curved arc surface, further improving the local stress concentration that may be caused by geometrical abrupt changes or asymmetrical structures at the outer edge 43, achieving a better stress relief effect.

[0074] Please see Figures 16 to 18 In one embodiment of this utility model, the end face 403 includes a first chamfered surface 4031 and a second chamfered surface 4032. Along the axial direction of the housing 10, the height of the first chamfered surface 4031 is d1, the height of the second chamfered surface 4032 is d2, and the thickness of the cover plate 40 is D, where 0 < d1 + d2 < D. Preferably, d1 + d2 = D. The relationship between d1 and d2 is not limited; for example, d1 can be greater than d2, or less than or equal to d2.

[0075] When 0 < d1 + d2 < D, it indicates that the first chamfered surface 4031 and the second chamfered surface 4032 are not directly connected, but there is a connecting surface 4033 in the above embodiment between them. This design can avoid the connection sharp corners or points that may be formed if the first chamfered surface 4031 and the second chamfered surface 4032 directly intersect, thereby better improving the stress concentration sources that may appear on the end face 403, and thus helping to achieve uniform distribution of stress acting on the end face 403.

[0076] Please see Figure 16 and Figure 17 In one embodiment of this utility model, along the axial direction of the housing 10, the height of the first chamfered surface 4031 is d1, the height of the second chamfered surface 4032 is d2, and the thickness of the cover plate 40 is D. Along the radial direction of the housing 10, the width of the first chamfered surface 4031 is L1, the width of the second chamfered surface 4032 is L2, L1≥L2>D, and d1≥d2.

[0077] Considering that during the mechanical sealing process, the lateral compressive force acting on the edge 43 of the cover plate 40 during the bending of the sidewall 11 and the sealing element 30 is mainly concentrated in the area corresponding to the first chamfered surface 4031, this area needs to have a larger residual space to better absorb and release stress. Therefore, in this embodiment, by limiting L1≥L2>D and d1≥d2, the overall area of ​​the first chamfered surface 4031 can be larger than the overall area of ​​the second chamfered surface 4032. This design ensures that during the mechanical sealing process, the main stress-bearing area corresponding to the edge 43 has a more sufficient stress buffering capacity, thereby more effectively dispersing the lateral compressive force acting on the edge 43 of the cover plate 40, reducing the risk of stress concentration on the cover plate 40, and improving the structural stability of the cover plate 40 and the reliability of the explosion-proof notch 41 area during the mechanical sealing process.

[0078] Please see Figure 4 and Figure 17 In one embodiment of this utility model, the thickness of the cover plate 40 is D, and the width of the groove top wall 132 along the radial direction of the housing 10 is L3, where L3 ≥ 2D. Specifically, the width of the groove top wall 132 refers to the distance between the end of the transition angle 133 away from the groove side wall 131 and the end of the groove top wall 132 near the axis 102 of the housing 10. The groove top wall 132 sealing element 30 includes a first sealing part 31, a second sealing part 32, and a third sealing part 33. The two ends of the second sealing part 32 are respectively connected to the first sealing part 31 and the third sealing part 33 to jointly enclose and form the second groove 34 in the above embodiment. The first sealing part 31 is located between the groove top wall 132 and the first surface 40 to achieve a seal between the groove top wall 132 and the first surface 401 of the cover plate 40. The second sealing part 32 is located between the groove side wall 131 and the end face 403 of the edge part 43 to achieve a seal between the groove side wall 131 and the end face 403 of the edge part 43. The third sealing part 33 is located between the bottom wall 135 of the groove and the second surface 402 to achieve a seal between the bottom wall 135 of the groove and the second surface 402.

[0079] Along the radial direction of the housing 10, the first sealing part 31 has a first inner edge 311 near the axis 102 of the housing 10, and the groove top wall 132 has a second inner edge 1321 near the axis 102 of the housing 10. The first inner edge 311 is located on the side of the second inner edge 1321 near the axis 102.

[0080] If the width L3 of the groove top wall 132 is less than 2D, the effective sealing area formed between the groove top wall 132 and the seal 30 will be too small, resulting in insufficient sealing compression of the seal 30. This can easily lead to leakage during high-pressure helium testing (i.e., the detection value < 1×10). -8 Pa·m 3The sealing performance of the cover plate 40 installed in the first groove 13 is not met due to the limitation of L3≥2D. Therefore, in this embodiment, by limiting L3≥2D, it is beneficial to ensure the sealing performance of the cover plate 40 installed in the first groove 13. By placing the first inner edge 311 of the first sealing part 31 on the radially inner side of the second inner edge 1321 of the groove top wall 132, this arrangement can improve the problem of insufficient exposed area of ​​the seal 30 due to inward shrinkage after mechanical sealing. This ensures that there is always sufficient sealing pressure between the first surface 401 of the cover plate 40 and the groove top wall 132, thereby improving the sealing effect of the cylindrical battery 100 and the sealing stability during long-term use.

[0081] Please see Figure 16 In one embodiment of the present invention, the thickness of the side wall 11 of the shell 10 is D1, the thickness of the cover plate 40 is D, and 1≤D / D1≤2.

[0082] In this embodiment, the ratio of the thickness D of the cover plate 40 to the thickness D1 of the sidewall 11 is set to 1 ≤ D / D1 ≤ 2. The main purpose is to achieve a balance between structure, performance, and cost while ensuring the safety of the cylindrical battery 100. Specifically, if the cover plate 40 is too thin (i.e., D / D1 < 1), the structural strength of the cover plate 40 will be insufficient. When the internal pressure of the cylindrical battery 100 increases, the cover plate 40 is prone to excessive deformation, leading to the failure of the seal between the cover plate 40 and the first groove 13. If the cover plate 40 is too thick (i.e., D / D1 > 2), although the structural strength of the cover plate 40 is sufficient, the processing difficulty of its explosion-proof groove 41 will increase, the processing cost will increase, and the weight of the cover plate 40 will also increase, affecting the energy density of the cylindrical battery 100. Therefore, in this embodiment, by setting the ratio of the thickness D of the cover plate 40 to the thickness D1 of the side wall 11 to 1≤D / D1≤2, the reliable sealing of the cover plate 40 can be ensured, and the processing cost of the explosion-proof groove 41 can be controlled, thereby improving the overall performance of the cylindrical battery 100.

[0083] In one embodiment of this utility model, the edge portion 43 of the cover plate 40 is formed with a stamped first chamfered surface 4031 and / or a second chamfered surface 4032. Specifically, in this embodiment, the first chamfered surface 4031 and the second chamfered surface 4032 on the cover plate 40 are both formed by one or two stamping processes. During the forming process, a rounded corner mold is used to roll out the chamfered surface area by gradually rolling, and then the excess material on the outer periphery of the plate is removed by a blanking process, finally forming the cover plate 40 with the first chamfered surface 4031 and the second chamfered surface 4032.

[0084] This embodiment employs a stamping process to directly form the first chamfer surface 4031 and / or the second chamfer surface 4032 on the edge of the cover plate 40. Compared to simple mechanical cutting, stamping does not remove material through cutting, but rather uses a die to directly shape the material into the desired chamfer shape. This method avoids the micro-cracks and stress concentration problems common in cutting processes, resulting in a denser internal structure and more complete metal flow lines in the chamfered area. This not only ensures precise and uniform chamfer surface dimensions but also improves durability and long-term operational reliability, while fully preserving the material's inherent strength characteristics. It is particularly suitable for large-scale production where structural safety and consistency requirements are high.

[0085] Please see Figure 19 In one embodiment of the battery pack 200 of this utility model, the battery pack 200 includes a housing 201 and at least one cylindrical battery 100; the housing 201 includes a first housing portion 2011 and a second housing portion 2012, which cover each other to form a receiving space, in which multiple cylindrical batteries 100 are housed, and the multiple cylindrical batteries 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.

[0086] Please see Figure 20 In one example of the electronic device 300 of this utility model, the electronic device 300 includes a working part and a battery pack 200. The working part is electrically connected to the battery pack 200 to obtain electrical power. The working part 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, ship, spacecraft, electric toy, and power tool, etc. The vehicle can be a fuel-powered car, a natural gas car, or a new energy vehicle. 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 embodiment of the invention does not impose any special limitations on the electronic device 300 described above. In one embodiment of the electronic device 300 of this invention, the electronic device 300 is a vehicle, the working part is the vehicle body, and the battery pack 200 is fixedly installed on the vehicle body to provide driving force for the vehicle and realize the operation of the vehicle.

[0087] 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 cylindrical battery, characterized in that, include: The housing includes a sidewall, one end of which is formed by an opening; the housing provides a receiving space, the sidewall includes an inner surface located within the receiving space, the sidewall is bent near the opening to form a first groove, the first groove has a groove opening communicating with the receiving space, the first groove and the groove opening are both continuously distributed along the circumference of the cylindrical battery, and a portion of the inner surface forms the inner surface of the first groove; Electrode assembly, housed within the housing space; Seals; A cover plate, the cover plate including a central portion and an edge portion surrounding the central portion and fitted within a first groove, the central portion having explosion-proof grooves; the sealing element covering the edge portion and located between the edge portion and the inner surface of the first groove; Wherein, along the thickness direction of the cover plate, the cover plate includes a first surface facing away from the electrode assembly and a second surface facing away from the first surface; the cover plate also includes an end face connecting the first surface and the second surface; the end face includes a first chamfered surface in contact with the first surface, the first chamfered surface being continuously distributed along the circumferential direction, and / or the end face includes a second chamfered surface in contact with the second surface, the second chamfered surface being continuously distributed along the circumferential direction.

2. The cylindrical battery according to claim 1, characterized in that, The end face includes only the first chamfered surface, which is a rounded corner surface. The two ends of the first chamfered surface are respectively connected to the first surface and the second surface. The height d1 of the first chamfered surface along the thickness direction is equal to the thickness D of the cover plate.

3. The cylindrical battery according to claim 1, characterized in that, The end face includes a first chamfered surface, a second chamfered surface, and a connecting surface. The first chamfered surface is connected to the second chamfered surface through the connecting surface. The connecting surface is a vertical surface.

4. The cylindrical battery according to claim 1, characterized in that, The first chamfered surface is a rounded corner surface; the first groove includes a groove sidewall, a groove top wall, and a transition angle. The groove sidewall is disposed around the outer periphery of the edge portion, and the groove top wall is disposed on the side of the cover plate away from the electrode assembly. The groove top wall is connected to the groove sidewall through the transition angle. The transition angle is a rounded corner, and the radius of the transition angle is smaller than the radius of the first chamfered surface. On a cross section passing through the axis of the housing, along the line connecting the center of the transition angle and the center of the first chamfered surface, the projected profile of the transition angle is located within the projected profile of the first chamfered surface.

5. The cylindrical battery according to claim 1, characterized in that, The end face includes only a first chamfered surface and a second chamfered surface, and the end of the first chamfered surface opposite to the first surface is connected to the end of the second chamfered surface opposite to the second surface.

6. The cylindrical battery according to claim 5, characterized in that, The first chamfered surface and the second chamfered surface are rounded surfaces with equal radii, and the height d1 of the first chamfered surface along the thickness direction is equal to the height d2 of the second chamfered surface along the thickness direction. The thickness of the cover plate is D, and d1+d2=D.

7. The cylindrical battery according to claim 3, characterized in that, Along the axial direction of the housing, the height of the first chamfered surface is d1, the height of the second chamfered surface is d2, 0 < d1 + d2 < D, and d1 ≥ d2; along the radial direction of the housing, the width of the first chamfered surface is L1, the width of the second chamfered surface is L2, and L1 ≥ L2 > D.

8. The cylindrical battery according to claim 4, characterized in that, The cover plate has a thickness of D. Along the radial direction of the housing, the width of the groove top wall is L3, and L3≥2D. The seal includes a first sealing portion located between the groove top wall and the edge portion. The first sealing portion has a first inner edge near the axis. The groove top wall has a second inner edge near the axis. The first inner edge is located on the side of the second inner edge near the axis. The side wall has a thickness of D1. The cover plate has a thickness of D, and 1≤D / D1≤2.

9. The cylindrical battery according to claim 1, characterized in that, The first chamfered surface and / or the second chamfered surface are formed on the cover plate by one or two stamping processes.

10. A battery pack, characterized in that, The cylindrical battery includes any one of claims 1 to 9.

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