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, an electrode assembly, a pole and a current collecting component, the shell comprises an end wall, and the end wall is provided with a pole hole; the electrode assembly is arranged in the shell; the pole is fixed on the end wall; the pole comprises a columnar part, a riveting part and a limiting part, and the riveting part and the limiting part are arranged at the two ends of the columnar part respectively; the columnar part penetrates through the pole hole; the surface, facing the electrode assembly, of the pole is a first surface, and the surface, deviating from the electrode assembly, of the pole is a second surface; the current collecting component is arranged between the electrode assembly and the end wall and is respectively welded with the electrode assembly and the pole; the surface, facing the end wall, of the limiting part, the surface, facing the end wall, of the riveting part and the outer surface of the columnar part are all provided with high-temperature-resistant insulating layers, and the area, welded to the current collecting component, of the first surface and the second surface are not provided with the high-temperature-resistant insulating layers. According to the utility model, the technical problem that insulation failure is easy to generate between the pole and the shell during thermal runaway can be improved.

Description

TECHNICAL FIELD

[0001] The utility model relates to a battery technical field, concretely relates to a secondary battery, battery pack and electronic device. BACKGROUND

[0002] In the prior art, in order to realize the insulation between the positive and negative poles of the secondary battery, an insulating piece is usually arranged between the pole and the end wall, and the insulating piece is basically made of plastic material at present, and the existing plastic material often has inherent defects such as insufficient melting point and poor heat resistance. When thermal runaway occurs in the parallel use of multiple secondary batteries, the high temperature generated is easy to cause the plastic material to melt, burn and carbonize, thereby causing the insulation failure between the pole and the shell, causing the positive and negative poles of the parallel secondary battery to contact, forming a secondary short circuit, causing heat spread and reducing the safety performance of the secondary battery. SUMMARY

[0003] The utility model provides a secondary battery, battery pack and electronic device to improve the technical problem that the pole and the shell of the parallel secondary battery are easy to cause insulation failure when thermal runaway occurs in the parallel use of multiple secondary batteries.

[0004] To achieve the above object and other related objects, the utility model provides a secondary battery, which comprises a shell, an electrode assembly, a pole and a current collecting member, the shell comprises an end wall, the end wall is provided with a pole hole, the electrode assembly is arranged in the shell, the pole is fixed to the end wall, the pole comprises a columnar portion, a riveting portion and a limiting portion, the riveting portion and the limiting portion are arranged at two ends of the columnar portion respectively, and both extend from the columnar portion to the outer periphery of the end wall, the columnar portion penetrates through the pole hole, and the riveting portion and the limiting portion are located on both sides of the thickness direction of the end wall respectively, the surface of the pole facing the electrode assembly is a first surface, and the surface of the pole away from the electrode assembly is a second surface, the current collecting member is arranged between the electrode assembly and the end wall and is welded with the electrode assembly and the pole respectively, wherein the surface of the limiting portion facing the end wall, the surface of the riveting portion facing the end wall and the outer surface of the columnar portion are all provided with a high-temperature-resistant insulating layer, and the first surface and the second surface are not provided with the high-temperature-resistant insulating layer.

[0005] In the secondary battery example of the utility model, the outer periphery of the riveting portion comprises a first side surface, the first side surface connects the first surface and the surface of the riveting portion facing the end wall, and the part of the first side surface close to the end wall is provided with the high-temperature-resistant insulating layer.

[0006] In the secondary battery example of the utility model, the limiting portion is arranged outside the shell, the riveting portion is arranged inside the shell, and the side surface of the riveting portion facing the electrode assembly is not provided with the high-temperature-resistant insulating layer.

[0007] In the secondary battery example of the utility model, the outer periphery of the limiting part comprises a second side surface, the second side surface is connected with the surface of the limiting part facing the end wall, and the second side surface is provided with a high-temperature-resistant insulation layer; the secondary battery further comprises a sealing piece, the sealing piece is clamped between the limiting part and the end wall, and the compression rate is greater than 40%; the outer periphery of the sealing piece does not exceed the outer periphery of the limiting part, the minimum distance between the outer periphery of the limiting part and the outer periphery of the sealing piece along the radial direction of the limiting part is less than or equal to 0.5 mm.

[0008] In the secondary battery example of the utility model, the secondary battery further comprises a lower plastic, the lower plastic is arranged on the side of the end wall facing the electrode assembly and at least partially extends between the riveting part and the end wall; the thickness of the lower plastic between the riveting part and the end wall is 0.5-1.5 mm.

[0009] In the secondary battery example of the utility model, the limiting part is located inside the shell, the riveting part is arranged outside the shell, the secondary battery further comprises a sealing piece and a lower plastic, the sealing piece is clamped between the limiting part and the end wall, the lower plastic is arranged around the outer periphery of the sealing piece and at least partially extends between the outer edge of the limiting part and the end wall, and the projection of the lower plastic on the end wall does not overlap with the projection of the sealing piece on the end wall.

[0010] In the secondary battery example of the utility model, the outer diameter of the limiting part is D1, the inner diameter of the lower plastic is D2, the outer diameter of the lower plastic is D3, the inner diameter of the shell is D4, and D1-D2>D4-D3.

[0011] In the secondary battery example of the utility model, the thickness of the high-temperature-resistant insulation layer is 0.001-0.5 mm.

[0012] In the secondary battery example of the utility model, the secondary battery further comprises a sealing piece, the sealing piece is clamped between the limiting part and the end wall, a first round corner is arranged between the columnar part and the limiting part, the surface of the limiting part facing the end wall is connected with the outer surface of the columnar part through the first round corner, the inner edge of the sealing piece is sealingly abutted with the outer surface of the columnar part and the first round corner, the radius of the first round corner is R1, and 0.5 mm≤R1≤2 mm.

[0013] In the secondary battery example of the utility model, a second round corner is arranged between the columnar part and the riveting part, the surface of the riveting part facing the end wall and the outer surface of the columnar part are connected through the second round corner, the radius of the second round corner is R2, and R2≥1 mm.

[0014] In the secondary battery example of the utility model, the high-temperature-resistant insulation layer is coated on the surface of the pole, the surface roughness Ra of the region of the pole corresponding to the region coated with the high-temperature-resistant insulation layer is 0.005-0.007 mm, and the surface roughness Rz is 0.015-0.045 mm.

[0015] The utility model also provides a battery pack, the battery pack includes the secondary battery of any one of above.

[0016] The utility model also provides an electronic device, the electronic device includes the battery pack of above.

[0017] The utility model discloses a secondary battery, through setting up high temperature resistant insulating layer on the surface of the limiting portion facing the end wall, the surface of the riveting portion facing the end wall and the outer surface of the columnar portion, when the multiple secondary batteries are in parallel use and heat runaway occurs, even if the insulating piece between the pole and the end wall fails to insulate due to high temperature, the high temperature resistant insulating layer can continue to insulate between the pole and the end wall, so the probability of insulating failure between the pole of the parallel secondary battery and the shell when heat runaway occurs can be reduced, thereby the risk of secondary short circuit between the adjacent secondary batteries can be reduced. BRIEF DESCRIPTION OF DRAWINGS

[0018] In order to more clearly illustrate the technical scheme in the embodiments of the utility model or the prior art, the drawings needed to be used in the embodiment or the prior art description will be briefly introduced below, and obviously, the drawings in the following description are only some embodiments of the utility model, and for those skilled in the art, other embodiments can be obtained according to these drawings without creative labor.

[0019] Figure 1 It is a three-dimensional overall structure schematic view of the secondary battery of the utility model one example;

[0020] Figure 2 It is an axial sectional view of the secondary battery of the utility model one example;

[0021] Figure 3 It is an electrode assembly structure schematic view of the secondary battery of the utility model one example;

[0022] Figure 4 It is Figure 2 It is the local enlarged view of area A;

[0023] Figure 5 It is the structure schematic view of the riveting portion of the secondary battery of the utility model one example and is arranged in the shell interior, and the pole surface is provided with high temperature resistant insulating layer;

[0024] Figure 6 It is the local enlarged view of the pole and the end wall connecting position of the secondary battery of the utility model one example;

[0025] Figure 7 Figure 2 is a partial structure schematic view of the riveting part of the secondary battery according to the present application;

[0026] Figure 8 Figure 3 is an enlarged view of the riveting part of the secondary battery according to the present application;

[0027] Figure 9 Figure 4 is a schematic view of the battery pack according to the present application;

[0028] Figure 10 Figure 5 is a schematic view of the electronic device according to the present application.

[0029] Element number explanation:

[0030] 100, secondary battery; 110, shell; 111, end wall; 1111, pole hole; 112, side wall; 113, opening; 120, electrode assembly; 121, positive pole sheet; 1211, positive current collector; 1212, first coating area; 1213, first non-coating area; 122, diaphragm; 123, negative pole sheet; 1231, negative current collector; 1232, second coating area; 1233, second non-coating area; 124, negative pole lug; 125, positive pole lug; 130, pole; 131, columnar part; 1311, first round corner; 1312, second round corner; 132, riveting part; 1321, first side surface; 1322, third surface; 133, limiting part; 1331, second side surface; 134, first surface; 135, second surface; 136, first insulation surface; 137, second insulation surface; 138, third insulation surface; 139, welding surface; 140, current collecting member; 150, high-temperature-resistant insulation layer; 160, sealing member; 170, lower plastic; 180, cover plate; 190, upper plastic; 200, battery pack; 210, box body; 211, first box body part; 212, second box body part; 300, electronic device; 310, working part. DETAILED DESCRIPTION

[0031] The following embodiments and particular examples illustrate the embodiments of the present application. Other advantages and effects of the present application can be easily understood by those skilled in the art from the content disclosed in the present specification. The present application can also be implemented or applied in other different embodiments, and various modifications or changes can be made to the details in the present specification without departing from the spirit of the present application. It should be noted that the following embodiments and 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 application are used to describe specific embodiments, but are not intended to limit the protection scope of the present application. The test methods not specified in the following embodiments are generally performed under conventional conditions or under conditions recommended by the manufacturers.

[0032] When the embodiments give a numerical range, it should be understood that, unless otherwise specified by the present application, each numerical range and any number between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present application are used by those skilled in the art and the present application, and any method, equipment and material of the prior art similar or equivalent to the method, equipment and material described in the embodiments of the present application can be used to implement the present application.

[0033] It should be understood that the terms such as "up", "down", "left", "right", "middle" and "one" in the present specification are only for the convenience of clear description, and are not intended to limit the scope of the present application. The change or adjustment of the relative relationship without substantial change of the technical content is also regarded as the scope of the present application.

[0034] Please refer to Figures 1 to 10 The present application provides a secondary battery 100, a battery pack 200 and an electronic device 300, which can reduce the probability of insulation failure between the pole 130 and the shell 110 of the parallel secondary battery 100 during thermal runaway, and reduce the risk of secondary short circuit between adjacent secondary batteries 100. At the same time, since the area where the first surface 135 and the current collecting member 140 are welded and the second surface 134 are not provided with the high-temperature-resistant insulation layer 150, the weldability between the pole 130 and the current collecting member 140 inside the shell 110, and the electrical connector outside the pole 130 and the shell 110 can be ensured, and the welding quality at the corresponding position can be ensured.

[0035] The secondary battery 100 can include a lithium ion battery, a lithium-sulfur battery, a sodium lithium ion battery, a sodium ion battery, or a magnesium ion battery, and the like, and the embodiments of the present application are not limited thereto. The secondary battery 100 can be in the shape of a cylinder, a flat body, a cuboid, or other shapes, and the embodiments of the present application are not limited thereto.

[0036] Referring to Figure 1 and Figure 2 , the structure of the secondary battery 100 is further described, which includes a housing 110, an electrode assembly 120, a pole 130, and a current collecting member 140.

[0037] The housing 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111. The connection between the end wall 111 and the side wall 112 can be achieved in various ways, such as one-piece stamping, one-piece casting, or separate welding, as long as a stable sealing and electrical connection relationship can be formed. The side wall 112 is not limited in shape and can be cylindrical or prismatic, or can be any other closed loop profile that can be matched with the end wall 111. In the present 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. The housing 110 formed by the end wall 111 and the side wall 112 has a receiving cavity for accommodating the electrode assembly 120, electrolyte, and other necessary components of the battery. Specifically, the diameter of the housing 110 can be determined according to the size of the electrode assembly 120, such as 18mm, 21mm, 46mm, etc. The material of the housing 110 can be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent rusting of the housing 110 during long-term use, a layer of anti-rust material such as metal nickel can be plated on the surface of the housing 110.

[0038] Referring to Figure 2 and Figure 3 , the electrode assembly 120 is arranged inside the housing 110, and the electrode assembly 120 is a component that undergoes an electrochemical reaction in the secondary battery 100. The housing 110 can contain one or more electrode assemblies 120. The electrode assembly 120 includes a pole and a separator 122, and the pole and the separator 122 are wound to form a winding structure. Specifically, in the present embodiment, the electrode assembly 120 includes a positive pole 121, a separator 122, and a negative pole 123 wound axially around the housing 110.

[0039] The positive electrode tab 121 includes a positive electrode current collector 1211 and a positive electrode active material layer coated on the positive electrode current collector 1211, and a first coated area 1212 coated with the positive electrode active material layer and a first uncoated area 1213 not coated with the positive electrode active material layer are formed on the positive electrode current collector 1211, the first coated area 1212 and the first uncoated area 1213 are arranged axially along the shell 110, the first uncoated area 1213 extends to the outside of the diaphragm 122 to one end of the height direction of the secondary battery 100, and is bent to the axis of the shell 110 to form a stacked positive electrode tab 125.

[0040] The negative electrode tab 123 includes a negative electrode current collector 1231 and a negative electrode active material layer coated on the negative electrode current collector 1231, and a second coated area 1232 coated with the negative electrode active material layer and a second uncoated area 1233 not coated with the negative electrode active material layer are formed on the negative electrode current collector 1231, the second coated area 1232 and the second uncoated area 1233 are arranged axially along the shell 110, the second uncoated area 1233 extends to the outside of the diaphragm 122 to the other end of the height direction of the secondary battery 100, and is bent to the axis of the shell 110 to form a stacked negative electrode tab 124.

[0041] The diaphragm 122 is arranged between the positive electrode tab 121 and the negative electrode tab 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, the positive electrode active material layer includes a positive electrode active material, and the positive electrode active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc. The material of the negative electrode current collector 1231 can be copper, the negative electrode active material layer includes a negative electrode active material, and the negative electrode active material can be carbon or silicon, etc. The base material of the diaphragm 122 can be polypropylene (PP) or polyethylene (PE), etc. In order to protect and insulate the battery cell, an insulating film can also be wrapped outside the battery cell, and the insulating film can be synthesized from PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or other high molecular polymer materials.

[0042] Please refer to Figure 2 and Figure 3Further, the positive electrode tab 125 faces the end wall 111 or the opening 113, and the negative electrode tab 124 faces the other end of the shell 110. In the embodiment, the positive electrode tab 125 faces the end wall 111, and is electrically connected to the pole 130 to make the pole 130 positively charged. The negative electrode tab 124 faces the opening 113, and the shell 110 is electrically connected to the negative electrode tab 124 to make the shell 110 negatively charged. However, in another embodiment, the negative electrode tab 124 can be connected to the pole 130, and the positive electrode tab 125 can be connected to the shell 110.

[0043] Please refer to Figure 2 The secondary battery 100 can further include a cover plate 180, which is sealingly installed in the opening 113. The outer edge of the cover plate 180 is shaped to correspond to the shape of the opening 113, and is connected to the side wall 112 to seal the opening 113. The installation mode of the cover plate 180 includes, but is not limited to, mechanical sealing or welding sealing. In the embodiment, the cover plate 180 is sealingly installed in the opening 113 by mechanical sealing.

[0044] Please refer to Figure 2 and Figure 4 The pole 130 is fixed to the end wall 111, and the end wall 111 is provided with a pole hole 1111. The pole 130 is installed in the pole hole 1111 and is insulated from the end wall 111. The pole 130 includes a columnar portion 131, a riveting portion 132, and a limiting portion 133. The riveting portion 132 and the limiting portion 133 are respectively arranged at two ends of the columnar portion 131 in the height direction, and both extend from the columnar portion 131 to the outer periphery of the end wall 111 in the radial direction of the end wall 111. The riveting portion 132 is arranged on one side of the end wall 111 in the thickness direction, and the limiting portion 133 is arranged on the other side of the end wall 111 in the thickness direction. Figure 4 In an embodiment, please refer to Figure 7 The riveting portion 132 is arranged on one side of the end wall 111 away from the electrode assembly 120, i.e., the outside of the shell 110, and the limiting portion 133 is arranged on one side of the end wall 111 facing the electrode assembly 120, i.e., the inside of the shell 110. In another embodiment, please refer to

[0045] Please refer to Figure 4The current collecting member 140 is arranged on the side of the electrode assembly 120 facing the end wall 111 and between the electrode assembly 120 and the end wall 111. One side of the current collecting member 140 is welded to the positive electrode tab 125, and the other side of the current collecting member 140 is welded to the surface of the part of the pole 130 facing the electrode assembly 120, thereby realizing the electrical connection between the pole 130 and the positive electrode tab 125.

[0046] Please refer to Figure 4 and Figure 5 The surface of the pole 130 facing the electrode assembly 120 is the first surface 134, and the surface of the pole 130 away from the electrode assembly 120 is the second surface 135. It should be noted that, in an embodiment, as shown in Figure 4 and Figure 5 , when the riveting part 132 is arranged inside the shell 110 and the limiting part 133 is arranged outside the shell 110, at this time, the first surface 134 refers to the combination of the surface of the riveting part 132 facing the electrode assembly 120 and the surface of the columnar part 131 facing the electrode assembly 120, and the second surface 135 refers to the combination of the surface of the limiting part 133 away from the electrode assembly 120 and the surface of the columnar part 131 away from the electrode assembly 120. In another embodiment, when the riveting part 132 is arranged outside the shell 110 and the limiting part 133 is arranged inside the shell 110, at this time, the first surface 134 refers to the combination of the surface of the limiting part 133 facing the electrode assembly 120 and the surface of the columnar part 131 facing the electrode assembly 120, and the second surface 135 refers to the combination of the surface of the riveting part 132 away from the electrode assembly 120 and the surface of the columnar part 131 away from the electrode assembly 120.

[0047] Please refer to Figure 5 and Figure 6 As shown, the surface of the limiting part 133 facing the end wall 111, the surface of the riveting part 132 facing the end wall 111, and the outer surface of the columnar part 131 are all provided with a high-temperature-resistant insulating layer 150 (as shown by the black thick line in Figure 5 and Figure 6 ). The first surface 134 and the second surface 135 are not provided with the high-temperature-resistant insulating layer 150. For the convenience of description, the surface of the limiting part 133 facing the end wall 111 is marked as the first insulating surface 136, the surface of the riveting part 132 facing the end wall 111 is marked as the second insulating surface 137, the outer surface of the columnar part 131 is marked as the third insulating surface 138, and the area of the second surface 135 welded to the current collecting member 140 is marked as the welding surface 139.

[0048] It should be noted that the high-temperature-resistant insulation layer 150 in the utility model refers to an insulation layer with a high-temperature resistance of 600 DEG C or above. The high-temperature-resistant insulation layer 150 can be a coating structure formed by coating a high-temperature-resistant insulation material on the surface of the pole 130, such as a ceramic coating, an epoxy resin layer, etc. The high-temperature-resistant insulation layer 150 can also be an oxide insulation layer formed by anodizing the surface of the pole 130, etc. For the convenience of description, in the following examples, the high-temperature-resistant insulation layer 150 is taken as a coating structure coated on the surface of the pole 130 for detailed description.

[0049] In the embodiment, the high-temperature-resistant insulation layer 150 is arranged on the surface of the limiting portion 133 facing the end wall 111, the surface of the riveting portion 132 facing the end wall 111 and the outer surface of the columnar portion 131, so that the high-temperature-resistant insulation layer 150 can better cover the position where the pole 130 can contact the end wall 111. When thermal runaway occurs in the parallel use of multiple secondary batteries 100, even if the insulation member between the pole 130 and the end wall 111 fails due to high temperature, the high-temperature-resistant insulation layer 150 can continue to play an insulation role between the pole 130 and the end wall 111, so that the probability of insulation failure between the pole 130 of the parallel secondary battery 100 and the shell 110 during thermal runaway can be reduced, thereby reducing the risk of secondary short circuit between adjacent secondary batteries 100. At the same time, since the first surface 134 and the second surface 135 are not provided with the high-temperature-resistant insulation layer 150, the weldability between the pole 130 and the current collecting member 140 inside the shell 110 and the electrical connecting member outside the shell 110 can be ensured, and the welding quality at the corresponding position can be ensured.

[0050] Please refer to Figures 4 to 6In the secondary battery 100 example of the utility model, the limiting portion 133 is arranged outside the shell 110, and the riveting portion 132 is arranged inside the shell 110. The outer periphery of the riveting portion 132 comprises a first side surface 1321, and the first side surface 1321 connects the first surface 134 and the surface of the riveting portion 132 facing the end wall 111, that is, the first side surface 1321 connects the first surface 134 and the second insulating surface 137. The part of the first side surface 1321 close to the end wall 111 is coated with a high-temperature-resistant insulating layer 150, that is, the part of the first side surface 1321 close to the second insulating surface 137 is coated with a high-temperature-resistant insulating layer 150. The first side surface 1321 can be a cylindrical surface structure arranged perpendicularly to the second insulating surface 137, or can be a frustum surface structure arranged obliquely to the second insulating surface 137, etc. Since the riveting portion 132 deforms and generates metal flow under the riveting force during the riveting deformation process, the part of the first side surface 1321 close to the second insulating surface 137 is converted into part of the second insulating surface 137. In order to ensure the insulation effect between the riveting portion 132 and the end wall 111, it is necessary to ensure that the position of the second insulating surface 137 is completely coated with the high-temperature-resistant insulating layer 150. In the embodiment, since the part of the first side surface 1321 close to the end wall 111 is coated with the high-temperature-resistant insulating layer 150, when the outer periphery of the riveting portion 132 deforms and generates metal flow under the riveting force, it can also be ensured that the surface of the riveting portion 132 facing the end wall 111 side is coated with the high-temperature-resistant insulating layer 150, thereby further ensuring the insulation effect between the riveting portion 132 and the end wall 111.

[0051] On the basis of the last embodiment, please refer to Figure 5 and Figure 6In the secondary battery 100 example of the utility model, riveting portion 132 one side surface facing electrode assembly 120 is not provided with high temperature resistant insulating layer 150 along the thickness direction of end wall 111. It needs to be explained that the one side surface of riveting portion 132 facing electrode assembly 120 can be the combined structure of multi-segment arc surface, can also be the combined structure of inclined plane and arc surface, etc., and the specific structure is related to riveting force and riveting strength in riveting process. In order to facilitate the description, the one side surface of riveting portion 132 facing electrode assembly 120 is marked as third surface 1322. Along the radial direction of end wall 111, one end of third surface 1322 and the outer periphery of the surface of first columnar portion 131 towards electrode assembly 120 side are connected, and the other end of third surface 1322 and first side surface 1321 are connected. Since the probability of third surface 1322 contacting end wall 111 is small when thermal runaway occurs, high temperature resistant insulating layer 150 is not provided on the one side surface of riveting portion 132 facing electrode assembly 120 (i.e. on third surface 1322), which will not affect the insulation effect between pole column 130 and end wall 111, and at the same time, the coating area of high temperature resistant insulating layer 150 on pole column 130 can be saved, which plays a role in reducing the cost of coating.

[0052] On the basis that limiting portion 133 is arranged outside shell 110, optionally, please refer to Figure 5 And Figure 6 In the secondary battery 100 example of the utility model, the outer periphery of limiting portion 133 includes second side surface 1331, second side surface 1331 is connected with the surface of limiting portion 133 facing end wall 111, that is, second side surface 1331 is connected with first insulating surface 136, and second side surface 1331 is provided with high temperature resistant insulating layer 150. The secondary battery 100 further comprises sealing element 160, the sealing element 160 is arranged around the outer periphery of columnar portion 131, and is clamped between limiting portion 133 and end wall 111. Sealing element 160 is in a compressed state, and the compression rate of sealing element 160 is greater than 40%. The outer periphery of sealing element 160 does not exceed the outer periphery of limiting portion 133, that is, the whole sealing element 160 is clamped between limiting portion 133 and the wall body of end wall 111 away from electrode assembly 120. Along the radial direction of end wall 111, the minimum distance L between the outer periphery of limiting portion 133 and the outer periphery of sealing element 160 is less than or equal to 0.5mm.

[0053] In the embodiment, the outer periphery of the limiting portion 133 is provided with the high-temperature-resistant insulating layer 150, and thus a good insulation effect can be formed between the outer periphery of the limiting portion 133 and the end wall 111. Therefore, no other additional insulating member, such as the upper plastic 190, needs to be arranged between the outer periphery of the limiting portion 133 and the end wall 111. Only the sealing member 160 needs to be arranged between the limiting portion 133 and the end wall 111. In this way, the number of mounting parts can be saved, the assembly height between the pole 130 and the end wall 111 can be reduced, and the height of the pole 130 protruding outside the shell 110 can be reduced. At the same time, the compression rate of the sealing member 160 is greater than 40%. In this way, the sealing performance of the sealing member 160 can be effectively ensured, and the probability of electrolyte leakage at the mounting position of the pole 130 can be reduced. In addition, the outer periphery of the sealing member 160 does not exceed the outer periphery of the limiting portion 133. In this way, the consistency of the appearance of the secondary battery 100 can be ensured. In addition, the minimum distance between the outer periphery of the limiting portion 133 and the outer periphery of the sealing member 160 is less than or equal to 0.5 mm. Therefore, the effective sealing area of the sealing member 160 between the limiting portion 133 and the end wall 111 can be increased, and the sealing performance of the sealing member 160 can be improved.

[0054] Optionally, referring to FIG. 1, in a case where the riveting portion 132 is arranged inside the shell 110, Figure 4 and Figure 6 In an example of the secondary battery 100, the secondary battery 100 further includes a lower plastic 170. The lower plastic 170 is arranged on the side of the end wall 111 facing the electrode assembly 120, and surrounds the outer periphery of the columnar portion 131. The material of the lower plastic 170 is not limited. For example, the lower plastic 170 can be an engineering plastic, such as soluble perfluoroalkoxy (PFA), polybutylene terephthalate (PBT), liquid crystal polymer (LCP), PP, polyphenylene sulfide (PPS), polycarbonate (PC), or an insulating rubber member. In the radial direction of the end wall 111, at least part of the lower plastic 170 extends between the riveting portion 132 and the end wall 111. At least another part of the lower plastic 170 extends towards the outer periphery of the end wall 111 to insulate the electrode assembly 120 and the end wall 111. The thickness of the part of the lower plastic 170 between the riveting portion 132 and the end wall 111 is 0.5-1.5 mm, for example, 0.5 mm, 1.0 mm, or 1.5 mm.

[0055] Since the side of the riveting portion 132 facing the end wall 111 is coated with the high-temperature-resistant insulating layer 150, only the high-temperature-resistant insulating layer 150 is needed to play an insulating role between the end wall 111 and the riveting portion 132, so the thickness of the lower plastic 170 arranged between the end wall 111 and the riveting portion 132 can be reduced. However, if the thickness of the lower plastic 170 between the end wall 111 and the riveting portion 132 is too small, the riveting sealing performance between the riveting portion 132 and the end wall 111 will be affected. In the embodiment, the thickness of the part of the lower plastic 170 between the riveting portion 132 and the end wall 111 is set to be between 0.5 mm and 1.5 mm, which can not only meet the requirement of reducing the thickness of the lower plastic 170 between the end wall 111 and the riveting portion 132, but also reduce the material consumption of the lower plastic 170 and the production cost of the lower plastic 170, and ensure the riveting sealing performance between the riveting portion 132 and the end wall 111.

[0056] Please refer to Figure 7 and Figure 8 In an example of the secondary battery 100 of the utility model, the limiting portion 133 is arranged inside the shell 110, and the riveting portion 132 is arranged outside the shell 110. The sealing member 160 is arranged around the outer periphery of the columnar portion 131, and the sealing member 160 is clamped between the limiting portion 133 and the wall body on the side of the end wall 111 facing the electrode assembly 120. The sealing member 160 can be coaxially arranged with the columnar portion 131 or can be arranged in a non-coaxial manner. The sealing member 160 can be in contact with the outer peripheral surface of the columnar portion 131 or can not be in contact with the outer peripheral surface of the columnar portion 131. Optionally, in the embodiment, the sealing member 160 is coaxially arranged with the columnar portion 131, and the inner annular surface of the sealing member 160 is in contact with the outer peripheral surface of the columnar portion 131 to form a better sealing connection between the sealing member 160 and the columnar portion 131. The lower plastic 170 is arranged around the outer periphery of the sealing member 160, at least part of the lower plastic 170 extends between the outer edge of the limiting portion 133 and the end wall 111, and another part of the lower plastic 170 extends towards the outer periphery of the end wall 111 to isolate the end wall 111 and the electrode assembly 120. The projection of the lower plastic 170 on the end wall 111 does not overlap the projection of the sealing member 160 on the end wall 111, that is, there is a gap 171 between the inner edge of the lower plastic 170 and the outer edge of the sealing member 160.

[0057] It should be noted that, in the embodiment, other insulating members can be arranged between the riveting portion 132 and the end wall 111, or only the high-temperature-resistant insulating layer 150 coated on the riveting portion 132 can be used for insulation. Preferably, in the embodiment, in order to further improve the positioning stability between the pole 130 and the end wall 111, the upper plastic 190 is further arranged between the riveting portion 132 and the end wall 111. The riveting portion 132 abuts against the end wall 111 through the upper plastic 190.

[0058] Since the limiting portion 133 is coated with a high-temperature-resistant insulating layer 150 towards the side surface of the end wall 111 (i.e. the first insulating surface 136), the insulation between the limiting portion 133 and the end wall 111 can be achieved only by the high-temperature-resistant insulating layer 150. Therefore, when there is a gap 171 between the inner edge of the lower plastic 170 and the outer edge of the sealing member 160, the insulation effect between the limiting portion 133 and the end wall 111 will not be affected. The provision of the gap 171 between the inner edge of the lower plastic 170 and the outer edge of the sealing member 160, on the one hand, can not only reserve a certain radial compression space for the sealing member 160, but also ensure that the sealing member 160 can be fully compressed, thereby ensuring the sealing performance of the sealing member 160. On the other hand, it can also reduce the area of the lower plastic 170 extending between the limiting portion 133 and the end wall 111, thereby reducing the material usage of the lower plastic 170 and reducing the production cost of the lower plastic 170.

[0059] On the basis of the above embodiment, in order to improve the assembly performance of the lower plastic 170 inside the shell 110, please refer to Figure 7 In an example of the secondary battery 100 of the utility model, the outer diameter of the limiting portion 133 is D1, the inner diameter of the lower plastic 170 is D2, the outer diameter of the lower plastic 170 is D3, and the inner diameter of the shell 110 is D4, and D1-D2>D4-D3. In this way, even if there is a large radial installation error between the lower plastic 170 and the limiting portion 133, the inner edge of the lower plastic 170 can still be clamped between the limiting portion 133 and the end wall 111, thereby ensuring the fixed connection between the lower plastic 170 and the end wall 111 and reducing the probability of connection failure between the lower plastic 170 and the end wall 111.

[0060] Please refer to Figure 5In the secondary battery 100 example of the utility model, the thickness range of high temperature resistant insulation layer 150 is 0.001~0.5mm. For example, it can be 0.001mm, 0.1mm, 0.25mm or 0.5mm etc. When the coating thickness of high temperature resistant insulation layer 150 is too thin, the insulation effect that high temperature resistant insulation layer 150 can produce is lower, and the adhesion strength between high temperature resistant insulation layer 150 and the surface of pole 130 is also weak, when riveting installation of pole 130, high temperature resistant insulation layer 150 is easy to peel off from the surface of pole 130, and then insulation failure is produced. When the coating thickness of high temperature resistant insulation layer 150 is too thick, high temperature resistant insulation layer 150 is redundant too much, not only will increase the production cost of high temperature resistant insulation layer 150, but also will cause the excessive increase of the overall quality of secondary battery 100, is not favorable for the quality energy density promotion of secondary battery 100. In the embodiment, by limiting the thickness of high temperature resistant insulation layer 150 between 0.001~0.5mm, not only can meet the insulation performance requirement of high temperature resistant insulation layer 150, meet the adhesion force size requirement between high temperature resistant insulation layer 150 and the surface of pole 130, reduce the risk of high temperature resistant insulation layer 150 from the surface of pole 130, ensure the stability of the insulation performance of high temperature resistant insulation layer 150, but also can reduce the production cost of high temperature resistant insulation layer 150, reduce the influence on the overall quality of secondary battery 100.

[0061] Please refer to Figure 5 And Figure 6 In the secondary battery 100 example of the utility model, the sealing piece 160 is clamped between the limiting portion 133 and the end wall 111, and the sealing piece 160 is arranged around the outer periphery of the columnar portion 131. A first fillet 1311 is arranged between the columnar portion 131 and the limiting portion 133, and the surface of the limiting portion 133 facing the end wall 111 (i.e., the first insulation surface 136) is connected to the outer surface of the columnar portion 131 (i.e., the third insulation surface 138) through the first fillet 1311. The inner edge of the sealing piece 160 is sealed and abuts against the outer surface of the columnar portion 131 and the first fillet 1311. The radius of the first fillet 1311 is R1, and 0.5mm≤R1≤2mm. It should be noted that when the limiting portion 133 is located outside the shell 110, the first fillet 1311 can be arranged between the columnar portion 131 and the limiting portion 133. When the limiting portion 133 is located inside the shell 110, the first fillet 1311 can also be arranged between the columnar portion 131 and the limiting portion 133.

[0062] By limiting the radius of the first fillet 1311 to 0.5mm≤R1≤2mm, the radius R1 of the first fillet 1311 can be prevented from being too small, thereby facilitating the setting of the high-temperature-resistant insulation layer 150 at the position of the first fillet 1311, ensuring the uniformity and integrity of the high-temperature-resistant insulation layer 150 coating, thereby ensuring the insulation effect at the position of the first fillet 1311, and further improving the insulation effect between the pole 130 and the end wall 111. At the same time, if the radius of the first fillet 1311 is too large, it will cause a large size interference with the inner edge of the sealing element 160, which will to some extent increase the compression unevenness of the sealing element 160 at the first fillet 1311, thereby reducing the sealing performance of the inner edge of the sealing element 160. In the embodiment, by limiting the radius of the first fillet 1311 to 0.5mm≤R1≤2mm, the radius of the first fillet 1311 can be effectively limited to be too large, thereby better ensuring the sealing performance of the sealing element 160.

[0063] Optionally, referring to Figure 5 In an example of the secondary battery 100 of the utility model, a second fillet 1312 is arranged between the columnar portion 131 and the riveting portion 132, the surface of the riveting portion 132 facing the end wall 111 (i.e. the second insulation surface 137) and the outer surface of the columnar portion 131 (i.e. the third insulation surface 138) are connected through the second fillet 1312, the radius of the second fillet 1312 is R2, and R2≥1mm. It should be noted that when the riveting portion 132 is located outside the shell 110, the second fillet 1312 can be arranged between the columnar portion 131 and the riveting portion 132. When the riveting portion 132 is located inside the shell 110, the second fillet 1312 can also be arranged between the columnar portion 131 and the riveting portion 132. Since the high-temperature-resistant insulation layer 150 is coated on the surface of the pole 130 before the riveting portion 132 is flanged, the high-temperature-resistant insulation layer 150 at the corresponding position will be subjected to a certain extrusion deformation stress during the flanging and deformation of the riveting portion 132, thereby affecting the adhesion between the high-temperature-resistant insulation layer 150 and the riveting portion 132. By limiting the radius R2 of the second fillet 1312 to R2≥1mm in the embodiment, the extrusion deformation stress of the high-temperature-resistant insulation layer 150 at the corresponding position during the flanging and deformation of the riveting portion 132 can be reduced, thereby reducing the probability of rupture and falling of the high-temperature-resistant insulation layer 150, to further ensure the insulation effect between the pole 130 and the end wall 111.

[0064] Optionally, referring to Figure 5In the secondary battery 100 example of the utility model, the high temperature resistant insulation layer 150 is coated on the surface of the pole 130, the surface roughness Ra of the pole 130 corresponding to the region where the high temperature resistant insulation layer 150 is coated is 0.005-0.007mm, for example, Ra can be 0.005mm, 0.006mm or 0.007mm etc., and the surface roughness Rz of the pole 130 corresponding to the region where the high temperature resistant insulation layer 150 is coated is 0.015-0.045mm, for example, Rz can be 0.015mm, 0.030mm or 0.045mm etc. By setting the surface roughness Ra of the pole 130 corresponding to the region where the high temperature resistant insulation layer 150 is coated to 0.005-0.007mm, and the surface roughness Rz to 0.015-0.045mm, the high temperature resistant insulation layer 150 can have a better adhesion depth on the surface of the pole 130, so as to ensure that the high temperature resistant insulation layer 150 and the surface of the pole 130 have good adhesion, thereby reducing the probability of the high temperature resistant insulation layer 150 falling off from the surface of the pole 130 during the assembly and use of the pole 130, and further reducing the probability of insulation failure between the pole 130 and the shell 110.

[0065] Please refer to Figure 9 In the battery pack 200 example of the utility model, the battery pack 200 comprises a box body 210 and at least one secondary battery 100; the box body 210 comprises a first box body part 211 and a second box body part 212, the first box body part 211 and the second box body part 212 are mutually covered to form an accommodating space, a plurality of secondary batteries 100 are accommodated in the accommodating space, and the plurality of secondary batteries 100 can be connected in series and / or parallel. The battery pack 200 can be a battery module, a battery pack, etc.

[0066] Please refer to Figure 10In an example of the electronic device 300, the electronic device 300 includes a working part 310 and a battery pack 200, and the working part 310 is electrically connected with the battery pack 200 to obtain power support. The working part 310 can be a unit component capable of obtaining the power of the battery pack 200 and making corresponding work, such as a fan blade rotating unit, a dust suction working unit of a dust collector, a wheel driving unit in an electric vehicle, and the like. The electronic device 300 can be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy, an electric tool, and the like. The vehicle can be a fuel automobile, a gas automobile, or a new energy automobile, and the new energy automobile can be a pure electric automobile, a hybrid electric automobile, or a range extended automobile, and the like. The spacecraft includes an airplane, a rocket, a space shuttle, a spacecraft, and the like. The electric toy includes a fixed or mobile electric toy, such as a game machine, an electric automobile toy, an electric ship toy, an electric airplane toy, and the like. The electric tool includes a metal cutting electric tool, a grinding electric tool, an assembling electric tool, and a railway electric tool, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an impact electric drill, a concrete vibrator, and an electric planer, and the like. The electronic device 300 is not specially limited in the embodiment of the present application. In an example of the electronic device 300, the electronic device 300 is a vehicle, the working part 310 is a vehicle body, and the battery pack 200 is fixedly installed on the vehicle body, thereby providing driving force for the vehicle and realizing the running of the vehicle.

[0067] The secondary battery has the high-temperature-resistant insulation layer arranged on the surface of the limiting part facing the end wall, the surface of the riveting part facing the end wall, and the outer surface of the columnar part, so that when the multiple secondary batteries are used in parallel and thermal runaway occurs, even if the insulation part between the pole and the end wall fails due to high temperature, the high-temperature-resistant insulation layer can continue to play an insulation role between the pole and the end wall, so that the probability of insulation failure between the pole of the parallel secondary battery and the shell during thermal runaway can be reduced, and the risk of secondary short circuit between adjacent secondary batteries can be reduced. At the same time, since the first surface and the second surface are not provided with the high-temperature-resistant insulation layer, the weldability between the pole and the current collecting member inside the shell and the electrical connecting member outside the shell can be ensured, and the welding quality at the corresponding position can be ensured.

[0068] Therefore, the practical problems in the prior art are effectively overcome, and the utility value and use significance are high. The above examples only exemplarily illustrate the principle and effect of the utility model, and are not used to limit the utility model. Any person skilled in the art can modify or change the above examples without departing from the spirit and scope of the utility model. Therefore, all equivalent modifications or changes completed by those skilled in the art without departing from the spirit and technical concept disclosed by the utility model should be covered by the claims of the utility model.

Claims

1. A secondary battery characterized by comprising: The secondary battery comprises: a shell comprising an end wall provided with a pole hole; an electrode assembly arranged in the shell; a pole fixed to the end wall; the pole comprises a columnar portion, a riveting portion and a limiting portion, the riveting portion and the limiting portion are arranged at two ends of the columnar portion respectively, and both extend from the columnar portion to the outer periphery of the end wall; the columnar portion penetrates through the pole hole, the riveting portion and the limiting portion are located at two sides of the thickness direction of the end wall respectively; the surface of the pole facing the electrode assembly is a first surface, and the surface of the pole away from the electrode assembly is a second surface; a current collecting member arranged between the electrode assembly and the end wall, and welded with the electrode assembly and the pole respectively; wherein the surface of the limiting portion facing the end wall, the surface of the riveting portion facing the end wall and the outer surface of the columnar portion are all provided with a high-temperature-resistant insulation layer, and the first surface and the area of the current collecting member welded with the first surface are not provided with the high-temperature-resistant insulation layer.

2. The secondary battery according to claim 1, characterized by The riveting portion is arranged in the interior of the shell, and the outer periphery of the riveting portion comprises a first side surface connecting the first surface and the surface of the riveting portion facing the end wall; the part of the first side surface close to the end wall is provided with the high-temperature-resistant insulation layer.

3. The secondary battery according to claim 2, characterized by The side surface of the riveting portion facing the electrode assembly is not provided with the high-temperature-resistant insulation layer.

4. The secondary battery according to claim 2, characterized by The outer periphery of the limiting portion comprises a second side surface connected with the surface of the limiting portion facing the end wall, and the second side surface is provided with the high-temperature-resistant insulation layer; the secondary battery further comprises a sealing member, the sealing member is clamped between the limiting portion and the end wall, and the compression rate is greater than 40%; the outer periphery of the sealing member does not exceed the outer periphery of the limiting portion, and the minimum distance between the outer periphery of the limiting portion and the outer periphery of the sealing member in the radial direction of the limiting portion is less than or equal to 0.5 mm.

5. The secondary battery according to claim 4, characterized by The secondary battery further comprises a lower plastic, the lower plastic is arranged on the side of the end wall facing the electrode assembly, and at least partially extends between the riveting portion and the end wall; the thickness of the lower plastic between the riveting portion and the end wall is 0.5-1.5 mm.

6. The secondary battery according to claim 1, characterized by The limiting portion is located in the interior of the shell, and the riveting portion is arranged in the exterior of the shell; the secondary battery further comprises a sealing member and a lower plastic, the sealing member is clamped between the limiting portion and the end wall, and the lower plastic is arranged around the outer periphery of the sealing member and at least partially extends between the outer edge of the limiting portion and the end wall; the projection of the lower plastic on the end wall does not overlap with the projection of the sealing member on the end wall.

7. The secondary battery according to claim 6, characterized by The outer diameter of the limiting portion is D1, the inner diameter of the lower plastic is D2, the outer diameter of the lower plastic is D3, the inner diameter of the shell is D4, and D1-D2>D4-D3.

8. The secondary battery according to claim 1, characterized by The thickness of the high-temperature-resistant insulation layer is 0.001-0.5 mm.

9. The secondary battery according to claim 8, characterized by The secondary battery further comprises a seal arranged between the limiting portion and the end wall; a first fillet is arranged between the cylindrical portion and the limiting portion, a surface of the limiting portion facing the end wall is connected with an outer surface of the cylindrical portion through the first fillet, an inner edge of the seal is sealedly abutted with the outer surface of the cylindrical portion and the first fillet, a radius of the first fillet is R1, and 0.5mm≤R1≤2mm.

10. The secondary battery according to claim 9, characterized by A second fillet is arranged between the cylindrical portion and the riveting portion, a surface of the riveting portion facing the end wall is connected with the outer surface of the cylindrical portion through the second fillet, a radius of the second fillet is R2, and R2≥1mm.

11. The secondary battery according to any one of claims 8 to 10, characterized by The high-temperature-resistant insulation layer is coated on a surface of the pole, a surface roughness Ra of the pole at a region where the high-temperature-resistant insulation layer is coated is 0.005-0.007mm, and a surface roughness Rz is 0.015-0.045mm.

12. A battery pack, characterized by The secondary battery comprises any one of claims 1-11.

13. An electronic device, comprising: The battery pack comprises claim 12.

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