Secondary battery, battery pack, and electronic device

Abstract

The utility model provides a secondary battery, a battery pack and an electronic device. The secondary battery comprises a shell, a pole and an insulating part, the shell comprises an end wall, and a pole hole is formed in the end wall; the pole comprises a columnar part penetrating through the pole hole and a riveting part folded towards the outer edge of the end wall relative to the columnar part; wherein the part, connected with the columnar part, of the riveting part is a transition part, and the transition part is subjected to material deformation when the riveting part is turned over towards the outer edge of the end wall; the insulating part is used for isolating the pole and the end wall and comprises a pressure-bearing part in contact with the pole, and the pressure-bearing part bears extrusion stress when the transition part is bent; wherein at least one of the transition part and the pressure-bearing part is provided with a stress buffer structure, and the stress buffer structure is used for relieving the pressure of the transition part on the pressure-bearing part; according to the utility model, the technical problem that a large extrusion force is generated on an insulating part in the riveting process of the pole column can be solved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and in particular to a secondary battery, a battery pack and an electronic device. Background Art

[0002] At present, cylindrical batteries are widely used in various industries due to their mature production technology, high yield rate, low processing cost, good safety performance and heat dissipation performance.

[0003] The pole of an existing cylindrical battery is usually fixedly connected to the end wall of the shell by riveting, and an insulating part is sandwiched between the pole and the end wall. During the assembly of the pole, the bending area of ​​the pole exerts a large extrusion force on the insulating part, and there is a risk of squeezing and breaking the insulating part, thereby causing a short circuit between the pole and the end wall. Utility Model Content

[0004] In view of the above shortcomings of the prior art, the utility model provides a secondary battery, a battery pack and an electronic device to improve the technical problem that the pole generates a large extrusion force on the insulating member during the riveting process.

[0005] To achieve the above-mentioned purpose and other related purposes, the utility model provides a secondary battery, which includes: a shell, a pole and an insulating member; the shell includes an end wall, and the end wall is provided with a pole hole; the pole includes a columnar portion passing through the pole hole and a riveted portion bent toward the outer edge of the end wall relative to the columnar portion, wherein the portion where the riveted portion connects with the columnar portion is a transition portion, and material deformation occurs in the transition portion when the riveted portion is folded toward the outer edge of the end wall; the insulating member is used to isolate the pole and the end wall, and includes a pressure-bearing portion in contact with the pole, and the pressure-bearing portion is subjected to extrusion stress when the transition portion is bent; wherein a stress buffer structure is provided on at least one of the transition portion and the pressure-bearing portion, and the stress buffer structure is used to relieve the pressure of the transition portion on the pressure-bearing portion.

[0006] In an example of the secondary battery of the present invention, along the height direction of the secondary battery, the riveted portion is located on the inner side of the shell.

[0007] In an example of the secondary battery of the present invention, the stress buffer structure includes a first stress buffer structure located in the transition portion, and the first stress buffer structure is disposed continuously or discontinuously around the columnar portion.

[0008] In an example of the secondary battery of the present invention, the stress buffer structure includes a first groove, and the wall thickness of the first groove is 0.3 mm to 1 mm.

[0009] In an example of the secondary battery of the present invention, the stress buffer structure includes a gap.

[0010] In an example of the secondary battery of the present invention, the transition portion is a non-smooth surface.

[0011] In an example of the secondary battery of the present invention, the stress buffer structure includes a second stress buffer structure located on the pressure-bearing part; the pressure-bearing part includes a first part arranged in the pole hole and a second part arranged between the riveting part and the end wall, and the first part and the second part are integrally formed.

[0012] In an example of the secondary battery of the present invention, the second stress buffer structure is located at the connection between the first part and the second part, and the second stress buffer structure includes a second groove, and the second groove is continuously or discontinuously arranged around the first part.

[0013] In an example of the secondary battery of the present invention, the second stress buffer structure is located in the second portion, and the second stress buffer structure includes a third groove, and the third groove is arranged to continuously or discontinuously surround the first portion.

[0014] In an example of the secondary battery of the present invention, the second stress buffer structure is located in the first part, and the second stress buffer structure includes a fourth groove, and the fourth groove is arranged to continuously or discontinuously surround the first part.

[0015] In an example of the secondary battery of the present invention, the stress buffer structure includes a third stress buffer structure arranged at the edge of the pole hole facing the riveted portion, the third stress buffer structure is a chamfer, and the chamfer shape is one or more of a wedge shape and an arc shape.

[0016] In an example of the secondary battery of the present invention, the secondary battery is a cylindrical battery.

[0017] In an example of the secondary battery of the present invention, the cylindrical battery includes a shell, one end of the shell is open and the other end is closed, and the closed end of the shell is provided with a pole hole.

[0018] In an example of the secondary battery of the present invention, the shell is a steel shell.

[0019] The utility model also provides a battery pack, which comprises any one of the above-mentioned secondary batteries.

[0020] The utility model also provides an electronic device, which comprises the battery pack mentioned above.

[0021] The secondary battery of the utility model is provided with a stress buffer structure on at least one of the transition part and the pressure-bearing part, so that the squeezing force of the pole on the insulating part during riveting can be reduced, and the riveting part can avoid the position where the stress of the insulating part is concentrated, thereby improving the problem of the insulating part breaking. At the same time, the utility model can also improve the problem of the insulating part warping away from the pole end, thereby improving the assembly quality of the secondary battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the utility model. For ordinary technicians in this field, other embodiments can be obtained based on these drawings without paying creative work.

[0023] Figure 1 This is a schematic structural diagram of an example of a secondary battery of the utility model;

[0024] Figure 2 This is a schematic diagram of the structure of an electrode assembly of an example of a secondary battery of the utility model;

[0025] Figure 3 for Figure 1 A partial enlarged view of the middle A;

[0026] Figure 4 for Figure 3 A partial enlarged view of point B in the middle;

[0027] Figure 5 This is a schematic diagram of the structure of the pole of the secondary battery example 1 of the utility model before riveting;

[0028] Figure 6 This is a schematic structural diagram of the pole of the second example of the secondary battery of the utility model before riveting;

[0029] Figure 7 This is a schematic structural diagram of the pole of the secondary battery example 3 of the utility model before riveting;

[0030] Figure 8 This is a schematic structural diagram of the pole of the secondary battery example 4 of the utility model before riveting;

[0031] Fig. 9 This is a schematic diagram of the structure of the pole after riveting in an example of the secondary battery of the utility model;

[0032] Fig.10 This is a schematic structural diagram of a pole after riveting in another example of a secondary battery of the utility model;

[0033] Fig.11 This is a schematic structural diagram of a pole after riveting in another example of the secondary battery of the utility model;

[0034] Fig.12 This is a schematic diagram of the structure of an insulating member in an example of a secondary battery of the utility model;

[0035] Fig.13 for Fig.12 A partial enlarged view of point C in the middle;

[0036] Fig.14 This is a schematic diagram of the structure of an insulating member in another example of a secondary battery of the utility model;

[0037] Fig.15 for Fig.14 A partial enlarged view of point D in the middle;

[0038] Fig.16 This is a schematic structural diagram of an insulating member in another example of a secondary battery of the utility model;

[0039] Fig.17 for Fig.16 A partial enlarged view of point E in the middle;

[0040] Fig.18 A schematic diagram of an example of a battery pack of the utility model;

[0041] Fig.19 It is a schematic diagram of an example of the electronic device of the present invention.

[0042] Component number description

[0043] 1. Electronic device; 10. Battery pack; 11. Working part; 101. Box; 102. Box cover; 100. Secondary battery; 110. Shell; 111. End wall; 1111. Post hole; 112. Side wall; 113. Opening; 120. Electrode assembly; 121. Positive electrode sheet; 1211. Positive current collector; 1212. First coating area; 1213. First uncoated area; 122. Separator; 123. Negative electrode sheet; 1231. Negative current collector; 1232. Second coating area; 1233. Second uncoated area; 124. Negative electrode tab; 125. Positive electrode tab; 130. Cover plate; 140. Post ; 141, riveted portion; 142, columnar portion; 143, limiting portion; 144, pole body; 145, transition portion; 150, insulating member; 151, pressure-bearing portion; 1511, first portion; 1512, second portion; 152, first insulator; 153, second insulator; 154, third insulator; 160, stress buffer structure; 161, first stress buffer structure; 1611, first groove; 1612, gap; 1613, corner; 162, second stress buffer structure; 1621, second groove; 1622, third groove; 1623, fourth groove; 163, third stress buffer structure. DETAILED DESCRIPTION

[0044] The following describes the implementation of the present invention through specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific implementations, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and the features in the embodiments can be combined with each other without conflict. It should also be understood that the terms used in the embodiments of the present invention are intended to describe specific implementation schemes, rather than to limit the scope of protection of the present invention. The test methods for which specific conditions are not specified in the following examples are usually carried out under conventional conditions or under the conditions recommended by the manufacturers.

[0045] When numerical ranges are given in the embodiments, it should be understood that unless otherwise specified in the present invention, both endpoints of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention are in accordance with the prior art mastery of those skilled in the art and the description of the present invention, and any method, device and material of the prior art similar or equivalent to the method, device and material in the embodiments of the present invention can also be used to implement the present invention.

[0046] It should be noted that the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in this specification are only for the convenience of description and are not used to limit the scope of implementation of the present utility model. Changes or adjustments to their relative relationships should be regarded as the scope of implementation of the present utility model without substantially changing the technical content.

[0047] In the present application, the secondary battery includes an electrode assembly, which is a component in the secondary battery where electrochemical reactions occur, and may include one or more electrode assemblies.

[0048] The secondary battery also includes a shell, a cover plate and a pole. The shell includes an end wall and a side wall surrounding the end wall. One end of the side wall has an opening. The electrode assembly can be assembled into the shell through the opening of the shell. The cover plate is used to cover the opening of the shell to achieve sealing. The pole passes through the end wall and is electrically connected to the electrode assembly to conduct the electrical energy generated by the electrode assembly.

[0049] In order to reduce the risk of short circuit, the pole and the end wall need to be insulated and isolated. Usually, an insulating member is sandwiched between the pole and the end wall. The insulating member is at least partially located between the pole and the end wall to insulate the pole and the end wall.

[0050] In the related art, when assembling the pole and the end wall, the pole is usually first inserted into the pole hole on the end wall from one side of the end wall so that the outer end of the pole extends to the other side of the end wall, and then the outer end of the pole is squeezed to form a rivet portion to fix the pole to the end wall.

[0051] During the folding process of the above-mentioned riveted part, the inner side of the riveted part is subjected to compressive stress, and the outer side is subjected to tensile stress. The material on the outer side is stretched, and the material on the inner side flows under the action of compressive stress, so the material is deformed at the bending part where the riveted part contacts the insulating part, and a bulge is formed. The bulge just contacts the stress concentration part of the insulating part. Under the dual action of the extrusion force of the riveted part and the bulge, the insulating part may be broken, resulting in insulation failure of the insulating part, and then short-circuiting the pole and the end wall. In addition, the insulating part may also be lifted up at the end away from the pole under the action of the extrusion force, thereby affecting the assembly quality of the battery.

[0052] In view of this, the utility model provides a technical solution, by arranging a stress buffer structure on at least one of the edge of the pole hole toward the rivet part, the position where the rivet part is bent relative to the columnar part, and the position where the insulating part and the rivet part are relative to each other, the squeezing force of the pole on the insulating part during riveting can be reduced, and the rivet part can avoid the position where the stress of the insulating part is concentrated, thereby improving the problem of the insulating part breaking. At the same time, the utility model can also improve the problem of the insulating part warping up at one end away from the pole, thereby improving the assembly quality of the secondary battery.

[0053] See also Figures 1 to 19 The utility model provides a secondary battery 100 , a battery pack 10 and an electronic device 1 . The secondary battery 100 includes a housing 110 , an electrode assembly 120 , a pole 140 and a cover plate 130 .

[0054] See also Figure 1 , Figure 1The schematic diagram of the structure of an example of a secondary battery of the utility model; the shell 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111. As long as a stable sealing and electrical connection relationship can be formed, the connection between the end wall 111 and the side wall 112 can be achieved in a variety of ways, such as integral stamping, integral casting or split welding. The surrounding of the side wall 112 is not limited, and can be cylindrical or prismatic, or can be surrounded along any other closed loop contour that can match the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, and the side wall 112 is cylindrical and surrounds the outer edge of the end wall 111, and a circular opening 113 is formed at the end of the side wall 112 away from the end wall 111. A housing cavity is formed in the shell 110 surrounded by the end wall 111 and the side wall 112, which is used to accommodate the electrode assembly 120, the electrolyte and other necessary battery components. Specifically, the diameter of the shell 110 can be determined according to the specific size of the electrode assembly 120, such as 18 mm, 21 mm, 46 mm, etc. The shell 110 can be made of a variety of materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent the shell 110 from rusting during long-term use, a layer of rust-proof material such as metal nickel can be plated on the surface of the shell 110.

[0055] See also Figure 1 and Figure 2 , Figure 2The schematic diagram of the electrode assembly structure of an example of the secondary battery of the present invention is as follows; the electrode assembly 120 is contained in the housing 110, and the electrode assembly 120 is a component where electrochemical reactions occur in the secondary battery 100. The housing 110 may contain one or more electrode assemblies 120. The electrode assembly 120 includes a pole piece and a separator 122, which are wound to form a winding structure. Specifically, in the present embodiment, the electrode assembly 120 includes a positive pole piece 121, a separator 122 and a negative pole piece 123 axially wound around the shell 110, the positive pole piece 121 includes a positive current collector 1211 and a positive active material layer coated on the positive current collector 1211, and a first coated area 1212 coated with the positive active material layer and a first uncoated area 1213 not coated with the positive active material layer are formed on the positive current collector 1211. The first coated area 1212 and the first uncoated area 1213 are arranged axially along the shell 110, and the first uncoated area 1213 extends to the outside of the separator 122 at one end in the height direction of the secondary battery 100, and is bent toward the axis of the shell 110 to form a stacked positive electrode ear 125. The negative electrode sheet 123 includes a negative electrode current collector 1231 and a negative electrode active material layer coated on the negative electrode current collector 1231. A second coating area 1232 coated with a negative electrode active material layer and a second uncoated area 1233 not coated with a negative electrode active material layer are formed on the negative electrode current collector 1231. The second coating area 1232 and the second uncoated area 1233 are arranged along the axial direction of the shell 110. The second uncoated area 1233 extends to the other end of the secondary battery 100 in the height direction to the outside of the diaphragm 122, and is bent toward the axis of the shell 110 to form a stacked negative electrode tab 124; the diaphragm 122 is arranged between the positive electrode sheet 121 and the negative electrode sheet 123 to separate the positive electrode active material layer and the negative electrode active material layer. Taking the lithium-ion secondary battery 100 as an example, the material of the positive electrode current collector 1211 can be aluminum, and the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium or lithium manganese oxide. The negative electrode current collector 1231 may be made of copper, and the negative electrode active material layer includes a negative electrode active material, which may be carbon or silicon, etc. The base material of the separator 122 may be PP (polypropylene) or PE (polyethylene), etc. In order to protect and insulate the battery cell, an insulating film may be coated on the outside of the battery cell, and the insulating film may be synthesized from PP, PE, PET, PVC or other high molecular polymer materials.

[0056] See also Figure 1 and Figure 2Further, the positive electrode tab 125 in the present invention faces the end wall 111 or the opening 113, and the negative electrode tab 124 faces the other end of the housing 110. In this embodiment, the positive electrode tab 125 faces the end wall 111 and is electrically connected to the pole 140 so that the pole 140 is positively charged, and the negative electrode tab 124 faces the opening 113, and the housing 110 is electrically connected to the negative electrode tab 124, so that it is negatively charged. However, in other embodiments, the negative electrode tab 124 can be connected to the pole 140, and the positive electrode tab 125 can be connected to the housing 110.

[0057] See also Figure 1 The cover plate 130 is sealed and installed on the opening 113; the outer edge shape of the cover plate 130 corresponds to the shape of the opening 113, and is connected to the side wall 112 to seal the opening 113. The installation method of the cover plate 130 includes but is not limited to mechanical sealing or welding sealing. In this embodiment, the cover plate 130 is sealed and blocked on the opening 113 by mechanical sealing.

[0058] See also Figures 1 to 4 , Figure 3 for Figure 1 A partial enlarged view of point A in the middle. Figure 4 for Figure 3 The partial enlarged view of the B in the figure; the end wall 111 is provided with a pole hole 1111, and the pole 140 is installed through the pole hole 1111 and is insulated from the end wall 111. The end of the pole 140 facing the electrode assembly 120 passes through the end wall 111 to be directly electrically connected to the positive pole ear 125 or is electrically connected through an indirect transfer. The structure of the pole 140 can be any suitable form that can pass through the end wall 111 and be electrically connected to the positive pole ear 125 of the electrode assembly 120. For example, the cross-section can be circular, square, prismatic, or a special-shaped profile that can achieve stable conductivity. The pole hole 1111 corresponds to the shape of the pole 140. In this embodiment, the cross-section of the pole 140 is circular.

[0059] The pole 140 includes a columnar portion 142 that passes through the pole hole 1111 and a riveted portion 141 that is bent toward the outer edge of the end wall 111 relative to the columnar portion 142; the cross-section of the columnar portion 142 can be circular, square, prismatic or other special-shaped contours that can achieve stable conductivity. Considering better sealing and matching effects, preferably, the columnar portion 142 is adapted to the pole hole 1111, that is, the shape of the pole hole 1111 corresponds to that of the columnar portion 142. In this embodiment, the cross-section of the columnar portion 142 is circular, and the circular design is convenient for processing, assembly and sealing. The portion where the riveted portion 141 is connected to the columnar portion 142 is the transition portion 145. During the riveting process of the pole 140, when the riveted portion 141 is folded toward the outer edge of the end wall 111, the inner side of the transition portion 145 is subjected to compressive stress, and the outer side is subjected to tensile stress. It should be noted that the side of the transition portion 145 facing the outer edge of the end wall 111 is the inner side, and the other side opposite to the inner side of the transition portion 145 is the outer side; the material on the outer side is stretched, and the material on the inner side flows under the action of compressive stress, so the transition portion 145 is deformed when the riveted portion 141 is folded toward the outer edge of the end wall 111. The pole 140 is made of a conductive metal material, and the material of the pole 140 can be copper, nickel, or aluminum. In this embodiment, the pole 140 is made of aluminum, and the selection of aluminum can easily perform the riveting process.

[0060] See also Figure 3 and Figure 4 The insulating member 150 is used to isolate the pole 140 from the end wall 111. The insulating member 150 is at least partially disposed between the riveted portion 141 and the end wall 111, and between the side wall of the pole hole 1111 and the columnar portion 142, so as to insulate and isolate the end wall 111 from the pole 140. The riveted portion 141 is bent in a direction away from the axis of the pole 140 and is connected to the columnar portion 142, playing a limiting role to limit the pole 140 from separating from the end wall 111 and to press and fix the insulating member 150. Specifically, the insulating member 150 includes a first insulator 152 and a second insulator 153 that are integrally formed. The first insulator 152 Located between the side wall of the pole hole 1111 and the columnar portion 142, it is used to isolate the side wall of the pole hole 1111 and the columnar portion 142. The second insulator 153 is pressed to the end wall 111 by the riveted portion 141. On the one hand, it is used to isolate the riveted portion 141 from the end wall 111, and on the other hand, it is used to isolate the electrode assembly 120 from the end wall 111. The first insulator 152 and the second insulator 153 are vertically arranged; the insulating member 150 includes a pressure-bearing portion 151 in contact with the pole 140, and the pressure-bearing portion 151 is pressed by the columnar portion 142 and the riveted portion 141 at the same time, so the pressure-bearing portion 151 will be subjected to extrusion stress when the transition portion 145 is bent.

[0061] Preferably, in other embodiments, please refer to Figure 3 and Figure 4The insulating member 150 further includes a third insulator 154 disposed between the limiting portion 143 and the end wall 111. The third insulator 154 and the first insulator 152 may be integrally formed or independently disposed, which is not limited here. In this embodiment, the third insulator 154 and the first insulator 152 are independently disposed. The insulating member 150 may be made of EPDM rubber, fluorosilicone rubber or fluororubber, etc., but is not limited thereto.

[0062] Furthermore, a stress buffer structure 160 is provided on at least one of the transition portion 145 and the pressure-bearing portion 151, and the stress buffer structure 160 is used to relieve the pressure of the pole 140 on the insulating member 150 during riveting. That is, the stress buffer structure 160 can be provided only on the transition portion 145, or only on the pressure-bearing portion 151. Regardless of whether the stress buffer structure 160 is provided at any of the two positions of the transition portion 145 and the pressure-bearing portion 151, it can play the effect of reducing the squeezing force of the riveted portion 141 on the insulating member 150. Of course, in some other embodiments, the stress buffer structure 160 can be provided at both the transition portion 145 and the pressure-bearing portion 151. The positions where the stress buffer structure 160 is provided on the transition portion 145 and the pressure-bearing portion 151 are not limited, and can be provided at any position. The stress buffer structure 160 can be in various forms, such as a groove or a chamfer, and the cross-sectional shape of the groove can be an arc, rectangle, triangle or other irregular shape. The angle and shape of the chamfer can also be various possibilities, which are not limited here, as long as it can alleviate the squeezing force of the riveted part 141 on the insulating part 150.

[0063] See also Figure 1 and Figure 3 to Figure 4 In an example of the secondary battery 100 of the present invention, the pole 140 also includes a limiting portion 143, which is connected to the other end of the columnar portion 142 away from the riveted portion 141 and protrudes from the outer side wall 112 of the columnar portion 142. The setting of the limiting portion 143 is used on the one hand to limit the pole 140 from being separated from the end wall 111, and on the other hand to be electrically connected to the electrode assembly 120 or the outside to conduct the electric energy generated by the electrode assembly 120. The cross-section of the limiting portion 143 can be circular, square, prismatic or other special-shaped contours that can achieve stable conductivity. In this embodiment, the cross-section of the limiting portion 143 is also circular.

[0064] See also Figure 1 and Figure 3 to Figure 4, along the height direction of the secondary battery 100, the rivet portion 141 is located on the inner side or the outer side of the shell 110. Specifically, the rivet portion 141 and the limiting portion 143 are respectively located on both sides of the end wall 111 to rivet and fix the pole 140 and the end wall 111. The rivet portion 141 can be located on the side of the end wall 111 close to the electrode assembly 120 and electrically connected to the electrode assembly 120. At this time, the limiting portion 143 is located on the other side of the end wall 111 for electrically connecting to an external electrical device to extract the electric energy generated by the electrode assembly 120; in other embodiments, the limiting portion 143 is located on the side of the end wall 111 close to the electrode assembly 120 and electrically connected to the electrode assembly 120. At this time, the rivet portion 141 is located on the other side of the end wall 111 for electrically connecting to an external electrical device to extract the electric energy generated by the electrode assembly 120.

[0065] In an example of the secondary battery 100 of the present invention, the rivet portion 141 is located on the inner side of the shell 110, and the limiting portion 143 is located on the outer side of the shell 110. Since the rivet portion 141 is formed by riveting later, its shape is uncontrollable due to external influences, while the limiting portion 143 is previously processed and has a regular and controllable shape, the limiting portion 143 is arranged on the outer side of the shell 110, which is both beautiful and conducive to the safety of electrical connection with external electrical devices.

[0066] See also Figures 3 to 11 In an example of the secondary battery 100 of the present invention, the stress buffer structure 160 includes a first stress buffer structure 161 located in the transition portion 145. The first stress buffer structure 161 is arranged to continuously surround or discontinuously surround the columnar portion 142. The first stress buffer structure 161 is located inside the transition portion 145. In the discontinuously surrounded setting, there is no limit on the number of interruptions and the length of the interruptions, which can be designed according to actual conditions. The first stress buffer structure 161 in the form of discontinuously surrounded can reduce the extrusion force of the pole 140 on the insulating member 150 during riveting, while also taking into account the riveting strength of the pole 140; the continuous surrounding setting can better alleviate the extrusion force of the pole 140 on the insulating member 150. As long as the wall thickness here is within the range of 0.3mm to 1mm, the riveted portion 141 of the pole 140 can also have a higher strength. The first stress buffer structure 161 in this embodiment is in the form of continuously surrounding the columnar portion 142.

[0067] See also Figures 5 to 8The first stress buffer structure 161 at this position needs to be preset on the outer wall of the pole body 144 before the pole body 144 is bent. When the pole body 144 is bent, it will bend along the location of the first stress buffer structure 161. The portion of the pole body 144 that is bent in the direction away from the axis of the pole 140 forms the riveted portion 141, and the unbent portion of the pole body 144 is the above-mentioned columnar portion 142. The existence of the first stress buffer structure 161, on the one hand, reduces the material of the pole body 144 that is deformed, and on the other hand, provides an accommodation space for the material flow generated by the riveted portion 141 on the inner side of the transition portion 145, and on the other hand, it can reduce the difficulty of bending.

[0068] For ease of understanding, the structure of the pole 140 before the riveting process is described below. The first stress buffer structure 161 is a groove provided on the outer wall of the pole body 144. The size and shape of the groove are not limited and can be rectangular, arc-shaped, elliptical, triangular, waist-shaped or other irregular shapes. Figures 5 to 8 , respectively illustrate several examples of the first stress buffer structure 161 provided on the outer wall of the pole body 144, example 1, such as Figure 5 As shown, Figure 5 Schematic diagram of the structure of the pole of the secondary battery example 1 of the utility model before riveting, the cross-sectional shape of the first stress buffer structure 161 is a rectangle, example 2, such as Figure 6 As shown, Figure 6 Schematic diagram of the structure of the pole of the second example of the secondary battery of the utility model before riveting, the cross-sectional shape of the first stress buffer structure 161 is waist-shaped, example three, such as Figure 7 As shown, Figure 7 Schematic diagram of the structure of the pole of the secondary battery example 3 before riveting of the utility model, the cross-sectional shape of the first stress buffer structure 161 is elliptical, example 4, such as Figure 8 , which is a schematic structural diagram of the pole of the secondary battery example 4 of the present invention before riveting, the cross-sectional shape of the first stress buffer structure 161 is circular.

[0069] Due to the different shapes and sizes of the first stress buffer structure 161 at this position, and the uncontrollable factors of material deformation, the first stress buffer structure 161 will form different shapes after riveting. There is no limitation on the shape. Figures 9 to 11 , respectively illustrating three common examples.

[0070] In an example of the secondary battery 100 of the present invention, as Fig. 9 As shown, Fig. 9This is a schematic diagram of the structure of the pole after riveting in an example of the secondary battery of the utility model. The first stress buffer structure 161 includes a first groove 1611. The shape of the first groove 1611 is not limited. Due to the uncertainty of material deformation, the first groove 1611 is an irregular groove in most cases. Further, the first groove 1611 can be arranged intermittently or continuously around the columnar portion 142, which is not limited here. The wall thickness of the first groove 1611 is 0.3mm~1mm. For the wall thickness of the first groove 1611, please refer to Fig. 9 As shown in h, the value of h can be, for example, 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1 mm, etc. The wall thickness within this size range can ensure the riveting strength of the riveted portion 141.

[0071] In another example of the secondary battery 100 of the present invention, Fig.10 As shown, Fig.10 This is a schematic diagram of the structure of the pole after riveting in another example of the secondary battery of the utility model. The first stress buffer structure 161 includes a gap 1612, and the gap 1612 is located in the transition portion 145. When the material is deformed to produce material flow and the size of the accumulation is equivalent to the space reserved by the preset first stress buffer structure 161, the groove of the first stress buffer structure 161 will have no margin, and after riveting is completed, a gap 1612 will be formed in the columnar portion 142 and the riveted portion 141.

[0072] In another example of the secondary battery 100 of the present invention, Fig.11 As shown, Fig.11FIG. 1 is a schematic diagram of the structure of the pole after riveting in another example of the secondary battery of the utility model. The transition part 145 is a non-smooth surface. According to prior knowledge, we know that the inner side of the transition part 145 is subjected to compressive stress, and the outer side is subjected to tensile stress. The material on the outer side is stretched, and the material on the inner side flows under the action of compressive stress. Therefore, at the bending part where the riveted part 141 contacts the insulating part 150, that is, the inner side of the transition part 145, material deformation occurs, and a convex smooth transition surface is formed. When the size of the material flow accumulation caused by the material deformation is equivalent to the space reserved by the preset first stress buffer structure 161, the deformed material fills the first stress buffer structure 161. In the groove of the structure 161, the protruding smooth transition curved surface disappears, and the riveted portion 141 and the columnar portion 142 are bonded as a whole. At this time, the transition portion 145 is formed into a non-smooth surface, and an edge 1613 is formed at the connection between the riveted portion 141 and the columnar portion 142, rather than the irregular protruding smooth transition curved surface formed in the prior art. Compared with the protruding smooth transition curved surface in the prior art, the edge 1613 increases the distance between the transition portion 145 and the pressure-bearing portion 151, that is, the compression amount of the riveted portion 141 on the insulating member 150 is reduced. This arrangement can reduce the extrusion force of the pole 140 on the insulating member 150 during riveting.

[0073] See also Figure 3 to Figure 4 During the riveting process of the pole 140 , the insulating member 150 is under the dual extrusion of the riveted portion 141 and the end wall 111 , in order to alleviate the problem of the insulating member 150 breaking or deforming and warping under the extrusion. In an example of the secondary battery 100 of the present invention, the stress buffer structure 160 includes a second stress buffer structure 162 located on the pressure-bearing part 151, and the pressure-bearing part 151 includes a first part 1511 arranged in the pole hole 1111 and a second part 1512 arranged between the riveted part 141 and the end wall 111, so as to achieve insulation between the pole 140 and the end wall 111. It should be noted that, along the axial projection of the secondary battery 100, the overlapping part of the second insulator 153 and the riveted part 141 is the second part 1512, and the first part 1511 and the second part 1512 are integrally formed. The insulating member 150 arranged in this way is relatively simple to process and assemble and has good sealing performance. The pressure-bearing part 151 is pressed against the end wall 111 by the columnar part 142 and the riveted part 141 at the same time.

[0074] Specifically, the second stress buffer structure 162 can be located on the side of the pressure-bearing portion 151 close to the pole 140, or on the side of the pressure-bearing portion 151 close to the end wall 111, which is not limited here. In this embodiment, the second stress buffer structure 162 is located on the side of the pressure-bearing portion 151 close to the end wall 111, and the insulating member 150 provided with this arrangement has better strength. On the other hand, the second stress buffer structure 162 can be provided at any position of the first part 1511 or the second part 1512, or at a combination of the above two positions. Figures 12 to 17 , respectively illustrate three examples of the second stress buffer structure 162 on the insulating member 150.

[0075] See also Figure 3 to Figure 4 and Figure 12 to Figure 13 In an example of the secondary battery 100 of the present invention, the second stress buffer structure 162 is located at the connection between the first portion 1511 and the second portion 1512, that is, a portion of the second stress buffer structure 162 is located at the first portion 1511, and another portion is located at the second portion 1512. Fig.12 and Fig.13 As shown, Fig.12 This is a schematic diagram of the structure of an insulating member in an example of a secondary battery of the utility model. Fig.13 for Fig.12 In the partial enlarged view at C in the middle, the second groove 1621 is continuously or discontinuously arranged around the first part 1511, that is, the second stress buffer structure 162 is located on the side facing the end wall 111. This arrangement makes the first insulator 152 tend to bend toward the end wall 111 during the extrusion process. On the one hand, it can reduce the contact with the edge of the pole hole 1111, and on the other hand, it can improve the problem of the first insulator 152 being bent toward the side of the electrode assembly 120 under the extrusion force. Further, the second stress buffer structure 162 includes a second groove 1621, and the cross-sectional shape of the second groove 1621 can be selected from a variety of options, which are not limited to this, for example, it can be: rectangular, arc-shaped, The second groove 1621 is in the shape of a waist, a triangle, an ellipse, any combination of the above figures or other irregular figures. The second groove 1621 is continuously or discontinuously arranged around the first part 1511. In the discontinuously arranged arrangement, there is no limit on the number of discontinuities and the length of the discontinuities, and it can be designed according to actual conditions. The second groove 1621 in the form of discontinuously arranged is capable of reducing the squeezing force of the pole 140 on the insulating member 150 during riveting while taking into account the structural strength of the insulating member 150. The continuously arranged arrangement can better alleviate the squeezing force of the pole 140 on the insulating member 150. In this embodiment, the second groove 1621 is in the form of continuously surrounding the first part 1511.

[0076] In another example of the secondary battery 100 of the present invention, see Figure 3 to Figure 4 and Figure 14 to Figure 15 , Fig.14 This is a schematic diagram of the structure of an insulating member in another example of a secondary battery of the utility model. Fig.15 for Fig.14 In the partial enlarged view at D in the figure, the second stress buffer structure 162 is located in the second part 1512, facing the side of the end wall 111, and the third groove 1622 is continuously or discontinuously arranged around the first part 1511. The specific position of the second part 1512 is not limited. The second stress buffer structure 162 is arranged on the side facing the end wall 111, so that the first insulator 152 has a tendency to warp toward the end wall 111 during the extrusion process, which can improve the problem of the first insulator 152 warping toward the electrode assembly 120 side under the extrusion force. At the same time, the second stress buffer structure 162 in the technical solution has the advantage of convenient demoulding during the processing; further, the second stress buffer structure 162 includes the third groove 1622, and the cross section of the third groove 1622 is There are many options for the surface shape, which are not limited to this. For example, it can be: rectangular, arc-shaped, waist-shaped, triangular, elliptical, any combination of the above shapes or other irregular shapes. The third groove 1622 is set to continuously surround or discontinuously surround the first part 1511. In the discontinuous surrounding setting, there is no limit on the number of interruptions and the length of the interruptions, which can be designed according to actual conditions. The third groove 1622 in the form of discontinuous surrounding can reduce the risk of breakage of the insulating part 150 while taking into account the structural strength of the insulating part 150. The continuous surrounding setting can better improve the effect of the insulating part 150 tilting toward the side of the electrode assembly 120 under the extrusion force. The third groove 1622 in this embodiment is in the form of continuously surrounding the first part 1511.

[0077] In another example of the secondary battery 100 of the present invention, please refer to Figure 16 to Figure 17 , Fig.16 This is a schematic diagram of the structure of an insulating member in another example of the secondary battery of the utility model. Fig.17 for Fig.16In the partial enlarged view at E in the middle, the second stress buffer structure 162 is located at the first part 1511, facing the side of the pole hole 1111, and the fourth groove 1623 is continuously or discontinuously arranged around the first part 1511. The specific position of the first part 1511 is not limited. The second stress buffer structure 162 is arranged on the side facing the end wall 111, so that the first insulator 152 has a tendency to warp toward the end wall 111 during the extrusion process, which can improve the problem of the first insulator 152 warping toward the side of the electrode assembly 120 under the extrusion force. Further, the second stress buffer structure 162 includes a fourth groove 1623, and the cross-sectional shape of the fourth groove 1623 can be selected from a variety of options, which are not limited. For example, it can be: rectangular, arc-shaped, waist-shaped, triangular, elliptical, any combination of the above figures or other irregular figures. The fourth groove 1623 is set to continuously surround or discontinuously surround the first part 1511. In the discontinuous surrounding setting, there is no limit on the number of interruptions and the length of the interruptions, which can be designed according to actual conditions. The fourth groove 1623 in the form of discontinuous surrounding can reduce the risk of fracture of the insulating member 150 while taking into account the structural strength of the insulating member 150. The continuous surrounding setting can better improve the effect of the insulating member 150 tilting toward the side of the electrode assembly 120 under the extrusion force. The fourth groove 1623 in this embodiment is in the form of continuously surrounding the first part 1511.

[0078] During the riveting process of the pole 140, since the insulating member 150 is subjected to the dual extrusion of the riveted portion 141 and the end wall 111, the effect of relieving the extrusion force of the pole 140 on the insulating member 150 can also be achieved by providing a stress buffer structure 160 on the end wall 111. In an example of the secondary battery 100 of the present invention, please refer to Figure 4 The stress buffer structure 160 includes a third stress buffer structure 163 arranged on the edge of the pole hole 1111 toward the riveted portion 141. This arrangement can avoid the edge of the end wall 111 from contacting the stress concentrated corner of the insulating member 150, thereby improving the risk of fracture of the insulating member 150. The third stress buffer structure 163 is a chamfer, and the chamfer shape is one or more of a wedge shape and an arc shape. It can be a wedge shape, an arc shape, or a combination of a wedge shape and an arc shape. The chamfer in this embodiment is a wedge shape.

[0079] See also Figure 1 In an example of the secondary battery 100 of the present invention, the secondary battery 100 is a cylindrical battery.

[0080] See also Figure 1 and Figure 2 In an example of the secondary battery 100 of the present invention, the cylindrical battery includes a shell 110 , one end of the shell 110 is open and the other end is closed, and a pole hole 1111 is provided at the closed end of the shell 110 .

[0081] In an example of the secondary battery 100 of the present invention, the shell 110 of the secondary battery 100 is a steel shell.

[0082] See also Fig.18 , Fig.18 This is a schematic diagram of an example of a battery pack of the utility model. The utility model also provides a battery pack 10, which includes any of the above-mentioned secondary batteries 100. In one embodiment of the battery pack 10 of the utility model, the battery pack 10 includes a box 101, a box cover 102 and a plurality of secondary batteries 100. The plurality of secondary batteries 100 are placed in the box 101, connected in series or in parallel, or in a mixture of series and parallel. The box cover 102 is sealed on the box 101 to protect the plurality of secondary batteries 100. It should be noted that, in addition to the secondary battery 100 of the utility model, the battery pack 10 may also include a thermal management system of the battery pack 10, a circuit board and other parts. The battery pack 10 may be a battery module or a battery pack, an energy storage cabinet, etc.; they will not be described one by one here.

[0083] See also Fig.19 , Fig.19 The schematic diagram of an example of an electronic device of the utility model, the utility model also provides an electronic device 1, the electronic device 1 includes the above-mentioned battery pack 10. The working part 11 is electrically connected to the battery pack 10 to obtain power support. As an example, the electronic device 1 is a vehicle, the vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle, the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc., but not limited to this. The working part 11 is a vehicle body, the battery pack 10 is arranged at the bottom of the vehicle body, and provides power support for the driving of the vehicle or the operation of the electrical components in the vehicle. However, in some other embodiments, the electronic device 1 can also be a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy and an electric tool, etc. Spacecraft include airplanes, rockets, space shuttles and spacecrafts, etc.; the working part 11 can be a unit component that can obtain the power of the battery pack 10 and perform corresponding work, such as a fan blade rotation unit, a vacuum cleaner dust removal unit, etc. Electric toys include fixed or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Electric tools include metal cutting electric tools, grinding electric tools, assembly electric tools, and railway electric tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers, etc. The present application embodiment does not impose any special restrictions on the above-mentioned electronic device 1.

[0084] The utility model secondary battery, by providing a stress buffer structure on at least one of the transition part and the pressure-bearing part, can reduce the extrusion force of the pole on the insulating part during riveting, so that the riveting part avoids the position where the stress of the insulating part is concentrated, thereby improving the problem of the insulating part breaking. At the same time, the utility model can also improve the problem of the end of the insulating part away from the pole tilting, thereby improving the assembly quality of the secondary battery. Therefore, the utility model effectively overcomes some practical problems in the prior art and has a high utilization value and use significance. The above embodiments are only illustrative of the principles and effects of the utility model, and are not used to limit the utility model. Anyone familiar with this technology can modify or change the above embodiments without violating the spirit and scope of the utility model. Therefore, all equivalent modifications or changes made by those with ordinary knowledge in the relevant technical field without departing from the spirit and technical ideas disclosed by the utility model should still be covered by the claims of the utility model.

Claims

1. A secondary battery, characterized in that: include: The housing comprises an end wall, wherein the end wall is provided with a pole hole; A pole, comprising a columnar portion penetrating the pole hole and a riveted portion connected to one end of the columnar portion and folded toward the outer edge of the end wall, wherein the portion where the riveted portion is connected to the columnar portion is a transition portion, and the transition portion undergoes material deformation when the riveted portion is folded toward the outer edge of the end wall; An insulating member, used to isolate the pole and the end wall, and comprising a pressure-bearing portion in contact with the pole, wherein the pressure-bearing portion bears extrusion stress when the transition portion is bent; Wherein, a stress buffer structure is provided on at least one of the transition portion and the pressure-bearing portion, and the stress buffer structure is used to relieve the pressure of the transition portion on the pressure-bearing portion.

2. The secondary battery according to claim 1, characterized in that: The rivet portion is located inside the housing along a height direction of the secondary battery.

3. The secondary battery according to claim 1, characterized in that: The stress buffer structure includes a first stress buffer structure located at the transition portion, and the first stress buffer structure is disposed continuously or discontinuously around the columnar portion.

4. The secondary battery according to claim 3, characterized in that: The first stress buffering structure includes a first groove, and the wall thickness of the first groove is 0.3 mm to 1 mm.

5. The secondary battery according to claim 3, characterized in that: The first stress buffering structure includes a gap.

6. The secondary battery according to claim 3, characterized in that: The transition portion is a non-smooth surface.

7. The secondary battery according to any one of claims 1 to 6, characterized in that: The stress buffer structure includes a second stress buffer structure located on the pressure-bearing portion; the pressure-bearing portion includes a first portion arranged in the pole hole and a second portion arranged between the riveting portion and the end wall, and the first portion and the second portion are integrally formed.

8. The secondary battery according to claim 7, characterized in that: The second stress buffering structure is located at the connection between the first part and the second part. The second stress buffering structure includes a second groove. The second groove is continuously or discontinuously arranged around the first part.

9. The secondary battery according to claim 7, characterized in that: The second stress buffering structure is located at the second portion, and the second stress buffering structure includes a third groove, and the third groove is arranged to continuously or discontinuously surround the first portion.

10. The secondary battery according to claim 7, characterized in that: The second stress buffering structure is located at the first portion, and the second stress buffering structure includes a fourth groove, and the fourth groove is arranged to continuously or discontinuously surround the first portion.

11. The secondary battery according to claim 7, characterized in that: The stress buffer structure comprises a third stress buffer structure provided at an edge of the pole hole facing the riveted portion, the third stress buffer structure is a chamfer, and the chamfer shape is one or more of a wedge shape and an arc shape.

12. The secondary battery according to claim 1, characterized in that: The secondary battery is a cylindrical battery.

13. The secondary battery according to claim 12, characterized in that: The cylindrical battery comprises a shell, one end of which is open and the other end is closed, and a pole hole is arranged at the closed end of the shell.

14. The secondary battery according to claim 13, characterized in that: The shell is a steel shell.

15. A battery pack, characterized in that: A secondary battery comprising the secondary battery according to any one of claims 1 to 14.

16. An electronic device, characterized in that: A battery pack comprising the battery pack of claim 15.

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