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 and a pole, 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 and is electrically connected with the electrode assembly; the pole comprises a columnar part, an outer flange and an inner flange, the outer flange and the inner flange are connected to the two ends of the columnar part respectively, the columnar part penetrates through the pole hole, the outer flange is located outside the shell, and the inner flange is located inside the shell; a first high-temperature-resistant insulating layer is arranged on the side, facing the inner flange, of the end wall, and the projection of the first high-temperature-resistant insulating layer on the end wall covers the projection of the inner flange on the end wall. The minimum distance between the projection outer contour of the first high-temperature-resistant insulating layer and the projection outer contour of the inner flange is c, the diameter of the pole hole is a, the diameter of the columnar part is b, and c is larger than or equal to (a-b) / 2. According to the utility model, the technical problem that insulation failure is easy to generate between the pole and the shell of the secondary battery 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] Secondary batteries have been widely used in the automotive industry due to high energy density and high cost performance. At present, most secondary batteries usually have a positive electrode as a pole and a negative electrode as a steel shell.

[0003] In the prior art, in order to realize the insulation between the positive and negative electrodes of the secondary battery, an insulating piece is usually arranged between the pole and the end wall. The insulating piece is basically made of plastic material at present. However, the existing plastic material has inherent defects such as insufficient melting point and poor heat resistance. When thermal runaway occurs in multiple parallelly connected secondary batteries, high temperature generated thereby can easily cause the plastic material to melt, burn and carbonize, thereby causing insulation failure between the pole and the shell of the parallelly connected secondary battery, resulting in contact between the positive and negative electrodes of the parallelly connected secondary battery and secondary short circuit between the connected batteries, causing heat spread and reducing the safety performance of the secondary battery. SUMMARY

[0004] 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 parallelly connected secondary battery are easy to cause insulation failure when thermal runaway occurs in multiple parallelly connected secondary batteries.

[0005] In order to achieve the above object and other related objects, the utility model provides a secondary battery, which comprises a shell, an electrode assembly and a pole. The shell comprises an end wall, and the end wall is provided with a pole hole with a diameter of a. The electrode assembly is arranged in the shell. The pole is fixed to the end wall and electrically connected to the electrode assembly. The pole comprises a columnar portion, an outer flange and an inner flange. The outer flange and the inner flange are respectively connected to the two ends of the columnar portion. The columnar portion penetrates the pole hole. The outer flange is located outside the shell, and the inner flange is located inside the shell. The end wall is clamped between the outer flange and the inner flange. The side of the end wall facing the inner flange is provided with a first high-temperature-resistant insulating layer. The projection of the first high-temperature-resistant insulating layer on the end wall covers the projection of the inner flange on the end wall. In the radial direction of the pole hole, the minimum distance between the projection outer contour of the first high-temperature-resistant insulating layer and the projection outer contour of the inner flange is c. The diameter of the columnar portion is b, and c is greater than or equal to (a-b) / 2.

[0006] In an example of the secondary battery of the utility model, the first high-temperature-resistant insulating layer is coated on the surface of the end wall. The surface roughness Ra of the area of the end wall corresponding to the area coated with the first high-temperature-resistant insulating layer is 0.005-0.007 mm, and the surface roughness Rz is 0.015-0.045 mm.

[0007] In the secondary battery example of the utility model, the base material of the shell is steel material, the component of the first high-temperature-resistant insulation layer includes ceramic particles, and the ceramic particles are inorganic substances.

[0008] In the secondary battery example of the utility model, the end wall includes a recess, the recess corresponds to the mounting position of the outer flange, and the side of the recess facing the electrode assembly is convex, the convex includes a top wall, and the first high-temperature-resistant insulation layer is arranged on the top wall.

[0009] In the secondary battery example of the utility model, the first high-temperature-resistant insulation layer is an insulation oxide layer formed on the surface of the end wall.

[0010] In the secondary battery example of the utility model, the thickness of the first high-temperature-resistant insulation layer is 0.001-0.5 mm.

[0011] In the secondary battery example of the utility model, the hole wall of the pole hole is provided with a second high-temperature-resistant insulation layer.

[0012] In the secondary battery example of the utility model, the side of the end wall facing the outer flange is provided with a third high-temperature-resistant insulation layer, the projection of the third high-temperature-resistant insulation layer on the end wall covers the projection of the outer flange on the end wall, along the radial direction of the pole hole, the minimum distance between the projection outer contour of the third high-temperature-resistant insulation layer and the projection outer contour of the outer flange is d, and d is greater than or equal to (a-b) / 2.

[0013] In the secondary battery example of the utility model, along the radial direction of the end wall, the minimum distance between the projection outer contour of the third high-temperature-resistant insulation layer and the outer circumference of the end wall is f, the diameter of the shell is D, and f is greater than or equal to (D-a) / 2.

[0014] The utility model also provides a battery pack, and the battery pack comprises the secondary battery of any one of the above.

[0015] The utility model also provides an electronic device, and the electronic device comprises the battery pack.

[0016] The utility model discloses secondary battery, because the first high temperature resistant insulating layer is arranged to the side of the inner flange of end wall, therefore, when the heat run away of multiple secondary batteries parallelly connected use occurs, even if the insulating failure of insulating piece between the inner flange and end wall occurs due to high temperature effect, the first high temperature resistant insulating layer can continue to play the insulating effect between the inner flange and end wall, can reduce the probability of insulating failure between the pole of parallelly connected secondary battery and shell when heat run away, thereby can reduce the risk of secondary short circuit between adjacent secondary battery. BRIEF DESCRIPTION OF DRAWINGS

[0017] In order to more clearly illustrate the technical scheme in the embodiment of the utility model or prior art, below will to the drawing needed to use in the embodiment or prior art description simple introduction, obviously, below description in the drawing only some embodiments of the utility model, for the ordinary skilled person in the art comes, under the premise of not paying creative labor, can also obtain other embodiments according to these drawings.

[0018] Figure 1 It is three-dimensional overall structure schematic diagram of secondary battery of the utility model one example;

[0019] Figure 2 It is axial section view of secondary battery of the utility model one example;

[0020] Figure 3 It is electrode assembly structure schematic diagram of secondary battery of the utility model one example;

[0021] Figure 4 It is Figure 2 It is the local enlarged view of area A;

[0022] Figure 5 It is the local enlarged view of the setting position of the first high temperature resistant insulating layer of secondary battery of the utility model one example in end wall;

[0023] Figure 6 It is the position size schematic diagram of the first high temperature resistant insulating layer and the first high temperature resistant insulating layer and pole between of secondary battery of the utility model one example;

[0024] Figure 7 It is the setting size schematic diagram of the first high temperature resistant insulating layer and the first high temperature resistant insulating layer in end wall of secondary battery of the utility model one example;

[0025] Figure 8 Figure 2 is a partial schematic view of the mounting position between the recess and the pole post when the end wall of the secondary battery is provided with the recess according to an embodiment of the present application;

[0026] Figure 9 Figure 3 is a schematic view of the battery pack according to an embodiment of the present application;

[0027] Figure 10 Figure 4 is a schematic view of the electronic device according to an embodiment of the present application.

[0028] Element number explanation:

[0029] 100, secondary battery; 110, shell; 111, end wall; 1111, pole post hole; 1112, body part; 1113, recess; 1114, bottom wall; 1115, protrusion; 1116, top wall; 1117, first high-temperature-resistant insulation layer; 1118, second high-temperature-resistant insulation layer; 1119, third high-temperature-resistant insulation layer; 112, side wall; 113, opening; 120, electrode assembly; 121, positive electrode sheet; 1211, positive current collector; 1212, first coating area; 1213, first non-coating area; 122, separator; 123, negative electrode sheet; 1231, negative current collector; 1232, second coating area; 1233, second non-coating area; 124, negative tab; 125, positive tab; 130, pole post; 131, columnar part; 132, inner flange; 133, outer flange; 140, current collecting member; 150, lower plastic; 151, first insulation part; 152, second insulation part; 160, upper plastic; 170, sealing member; 180, cover plate; 200, battery pack; 210, box body; 211, first box body part; 212, second box body part; 300, electronic device; 310, working part. DETAILED DESCRIPTION

[0030] The above embodiments and their features can be combined with each other on the premise of no conflict. It should be understood that the terms used in the embodiments of the present application are used to describe specific embodiments, but not to limit the protection scope of the present application. The test methods not specified in the following embodiments are usually performed under conventional conditions or under the conditions recommended by the manufacturers.

[0031] When the embodiments give a numerical range, it should be understood that, unless otherwise stated by the utility model, both ends of each numerical range and any one numerical between the two ends can be selected. Unless otherwise defined, all technical and scientific terms used in the utility model are used by the skilled in the art and the description of the utility model, and any method, equipment and material of the prior art similar or equivalent to the method, equipment and material in the embodiments of the utility model can be used to realize the utility model.

[0032] It should be understood that the terms such as "upper", "lower", "left", "right", "middle" and "one" cited in the specification are only for the convenience of clear description, and are not used to limit the scope of the utility model, and the change or adjustment of the relative relationship is also regarded as the scope of the utility model without substantial change of technical content.

[0033] Please refer to Figures 1 to 10 The utility model provides a kind of secondary battery 100, battery pack 200 and electronic device 300, the secondary battery 100 can reduce the probability of insulation failure between the pole 130 of parallel secondary battery 100 and shell 110 when thermal runaway by being provided with first high-temperature-resistant insulation layer 1117 towards the side of electrode assembly 120 of end wall 111, reduce the risk of secondary short circuit between adjacent secondary battery 100.It is further ensured that the insulation effect between the pole 130 of secondary battery 100 and shell 110 when thermal runaway by limiting the relative size between first high-temperature-resistant insulation layer 1117 and pole 130, pole hole 1111.

[0034] In the utility model, secondary battery 100 can include lithium ion battery, lithium-sulfur battery, sodium lithium ion battery, sodium ion battery or magnesium ion battery, etc., and the embodiments in the utility model are not limited to this.Secondary battery 100 can be cylindrical, flat, cuboid or other shapes, and the embodiments of the utility model are not limited to this.

[0035] Please refer to Figure 1 And Figure 2 Further describe the structure of secondary battery 100, which includes shell 110, electrode assembly 120 and pole 130.

[0036] The shell 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 can surround in a cylindrical or prismatic shape, or any other closed-loop profile that can match the end wall 111. In the embodiment, the outer edge of the end wall 111 is circular, and the side wall 112 surrounds the outer edge of the end wall 111 in a cylindrical shape, and a circular opening 113 is formed at the end of the side wall 112 away from the end wall 111. The end wall 111 and the side wall 112 form a housing 110 inside which an electrode assembly 120, an electrolyte and other necessary components of the battery are accommodated. Specifically, the diameter of the shell 110 can be determined according to the specific size of the electrode assembly 120, such as 18mm, 21mm, 46mm, etc. The shell 110 can be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent rusting of the shell 110 during long-term use, a layer of anti-rust material such as metal nickel can be plated on the surface of the shell 110.

[0037] Please refer to Figure 2 and Figure 3 The electrode assembly 120 is disposed inside the shell 110, and the electrode assembly 120 is a component in which an electrochemical reaction occurs in the secondary battery 100. The shell 110 can contain one or more electrode assemblies 120. The electrode assembly 120 includes a tab and a separator 122, and the tab and the separator 122 are wound to form a wound structure. Specifically, in the embodiment, the electrode assembly 120 includes a positive electrode tab 121, a separator 122 and a negative electrode tab 123 wound axially around the shell 110.

[0038] 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. The positive electrode current collector 1211 has 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. 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 separator 122 at one end of the secondary battery 100 in the height direction, and is bent towards the axis of the shell 110 to form a stacked positive electrode tab 125.

[0039] 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, 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 towards the other end of the height direction of the secondary battery 100, and is bent towards the axis of the shell 110 to form a stacked negative electrode tab 124.

[0040] 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, 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 by PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC) or other high molecular polymer materials.

[0041] Please refer to Figure 2 and Figure 3 , further, the positive electrode tab 125 in the utility model faces the end wall 111 or faces the opening 113, then 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 with the pole 130 to make the pole 130 carry positive electricity, the negative electrode tab 124 faces the opening 113, and the shell 110 is electrically connected with the negative electrode tab 124, so as to carry negative electricity. However, in another embodiment, the negative electrode tab 124 can be connected with the pole 130, and the positive electrode tab 125 can be connected with the shell 110.

[0042] Please refer to Figure 2 , the secondary battery 100 can further include a cover plate 180, and the cover plate 180 is sealingly installed in the opening 113; the outer edge shape of the cover plate 180 corresponds to the shape of the opening 113, and is connected with the side wall 112 to seal the opening 113, and the installation mode of the cover plate 180 includes but is not limited to mechanical sealing or welding sealing, and in the embodiment, the cover plate 180 is sealingly sealed on the opening 113 in the mode of mechanical sealing.

[0043] Please refer to Figure 2 and Figure 3 The pole 130 is fixed to the end wall 111 and is electrically connected with the electrode assembly 120. Specifically, the end wall 111 is provided with a pole hole 1111, and the pole 130 is installed through the pole hole 1111 and is insulated from the end wall 111. The end of the pole 130 towards the electrode assembly 120 can be directly electrically connected with the positive electrode tab 125 through the end wall 111, or can be indirectly electrically connected with the positive electrode tab 125 through the current collecting member 140. Optionally, in the embodiment, the side of the electrode assembly 120 towards the end wall 111 is provided with the current collecting member 140, the current collecting member 140 is electrically connected with the positive electrode tab 125, and the pole 130 is electrically connected with the current collecting member 140 after passing through the end wall 111, thereby realizing electrical connection with the positive electrode tab 125.

[0044] Specifically, please refer to Figure 4 The pole 130 includes a columnar portion 131, an inner flange 132 and an outer flange 133. The columnar portion 131 passes through the pole hole 1111 and is insulated therefrom. The inner flange 132 is arranged at one end of the columnar portion 131 in the height direction and is located inside the shell 110. The outer flange 133 is arranged at the other end of the columnar portion 131 in the height direction and is located outside the shell 110. The inner flange 132 and the outer flange 133 both extend from the columnar portion 131 to the outer periphery of the end wall 111 along the radial direction of the end wall 111, and the end wall 111 is clamped between the inner flange 132 and the outer flange 133. The inner flange 132, the outer flange 133 and the columnar portion 131 can be coaxially arranged or non-coaxially arranged. In order to facilitate positioning and machining, the inner flange 132 and the outer flange 133 are coaxially arranged with the columnar portion 131 in the embodiment.

[0045] Please refer to Figure 2 and Figure 4In order to realize the insulation and sealed connection between the pole 130 and the shell 110, the secondary battery 100 can further include a lower plastic 150, an upper plastic 160 and a sealing member 170. The material of the lower plastic 150 can be any one of Perfluoroalkoxy (PFA), Polybutylene Terephthalate (PBT), Liquid Crystal Polymer (LCP), PP, Polyphenylene Sulfide (PPS) and Polycarbonate (PC), without limitation. The lower plastic 150 is arranged around the outer periphery of the columnar portion 131, and specifically, the lower plastic 150 includes a first insulation portion 151 and a second insulation portion 152 connected to each other, and the first insulation portion 151 is in abutting contact with the wall of the end wall 111 facing the electrode assembly 120. In the radial direction of the pole hole 1111, one end of the first insulation portion 151 extends between the inner flange 132 and the end wall 111, and the other end of the first insulation portion 151 extends towards the outer periphery of the end wall 111, so as to isolate the electrode assembly 120 from the end wall 111. In the thickness direction of the end wall 111, one end of the second insulation portion 152 is connected to the first insulation portion 151, and the other end of the second insulation portion 152 extends between the pole hole 1111 and the columnar portion 131, and forms a full-enclosing structure for the pole hole 1111, so as to isolate the columnar portion 131 from the pole hole 1111.

[0046] Please refer to Figure 4 The upper plastic 160 and the sealing member 170 are arranged between the outer flange 133 and the end wall 111, wherein the sealing member 170 is annularly arranged around the outer periphery of the columnar portion 131, and the sealing member 170 is clamped between the outer flange 133 and the wall of the end wall 111 away from the electrode assembly 120. The upper plastic 160 is annularly arranged around the outer periphery of the sealing member 170, and the outer edge of the upper plastic 160 covers the outer periphery of the outer flange 133, and at least partially extends into the space between the outer flange 133 and the end wall 111, so as to realize the insulation between the outer periphery of the outer flange 133 and the end wall 111. The material of the upper plastic 160 can be PFA, PBT, LCP, PP, PPS or PC, without limitation.

[0047] Please refer to Figure 4 and Figure 5The side of the end wall 111 facing the inner flange 132 is provided with a first high-temperature-resistant insulating layer 1117. The first high-temperature-resistant insulating layer 1117 can be a coating structure formed by coating a high-temperature-resistant insulating material on the surface of the end wall 111, such as a ceramic coating, an epoxy resin layer, or the like. The first high-temperature-resistant insulating layer 1117 can also be an oxide insulating layer formed by anodizing the surface of the end wall 111, or the like. The projection of the first high-temperature-resistant insulating layer 1117 on the end wall 111 covers the projection of the inner flange 132 on the end wall 111. In the radial direction of the end wall 111, the minimum distance between the projected outer contour of the first high-temperature-resistant insulating layer 1117 and the projected outer contour of the inner flange 132 is c, the diameter of the pole hole 1111 is a, the diameter of the columnar portion 131 is b, and c≥(a-b) / 2. It should be noted that the projected outer contour of the first high-temperature-resistant insulating layer 1117 can be a circular contour, a square contour, a polygonal contour, or the like, and is not limited in this regard. Optionally, in this embodiment, in order to facilitate the positioning of the first high-temperature-resistant insulating layer 1117 on the end wall 111, the projected outer contour of the first high-temperature-resistant insulating layer 1117 is a circular contour, and is coaxially arranged with the pole hole 1111.

[0048] In this embodiment, since the side of the end wall 111 facing the inner flange 132 is provided with the first high-temperature-resistant insulating layer 1117, when thermal runaway occurs in the parallel use of multiple secondary batteries 100, even if the lower plastic 150 between the inner flange 132 and the end wall 111 is subjected to high-temperature action and causes thermal melting, carbonization, or the like, resulting in insulation failure, the first high-temperature-resistant insulating layer 1117 can continue to play an insulating role between the inner flange 132 and the end wall 111, thereby reducing the probability of insulation failure between the pole 130 of the parallel secondary battery 100 and the shell 110 during thermal runaway, reducing the risk of secondary short circuit between adjacent secondary batteries 100, and reducing the heat spread phenomenon caused by thermal runaway. At the same time, the minimum distance between the projected outer contour of the first high-temperature-resistant insulating layer 1117 and the projected outer contour of the inner flange 132 is c, the diameter of the pole hole 1111 is a, the diameter of the columnar portion 131 is b, and c≥(a-b) / 2. In this way, when the second insulating portion 152 between the columnar portion 131 and the pole hole 1111 is thermally melted and detached, and the pole 130 has the maximum radial offset relative to the pole hole 1111, the projection of the first high-temperature-resistant insulating layer 1117 can still cover the projection of the inner flange 132, and the first high-temperature-resistant insulating layer 1117 can always play an insulating role between the inner flange 132 and the end wall 111, thereby ensuring the insulation effect between the pole 130 and the shell 110 in the extreme case of complete thermal melting and detachment of the second insulating portion 152.

[0049] Please refer to Figure 7In the secondary battery 100 example of the utility model, the first high temperature resistant insulation layer 1117 is coated on the surface of the end wall 111, the surface roughness Ra of the region of the end wall 111 corresponding to the first high temperature resistant insulation layer 1117 is 0.005-0.007mm, for example, Ra can be 0.005mm, 0.006mm or 0.007mm etc.. The surface roughness Rz of the region of the end wall 111 corresponding to the first high temperature resistant insulation layer 1117 is 0.015-0.045mm, for example, Rz can be 0.015mm, 0.030mm or 0.045mm etc.. Since, during the use of the secondary battery 100, the end wall 111 will be subjected to the pressure inside the shell 110, a certain deformation is generated, when the deformation of the end wall 111 is large, it will cause the first high temperature resistant insulation layer 1117 to crack and fall off on the surface of the end wall 111, reducing the insulation effect. And the embodiment, by setting the surface roughness Ra of the region of the end wall 111 corresponding to the first high temperature resistant insulation layer 1117 to 0.005-0.007mm and the surface roughness Rz to 0.015-0.045mm, the first high temperature resistant insulation layer 1117 and the surface of the end wall 111 have a better adhesion depth, so as to ensure that the first high temperature resistant insulation layer 1117 and the surface of the end wall 111 have good adhesion, thereby reducing the probability of the first high temperature resistant insulation layer 1117 falling off from the surface of the end wall 111, and further reducing the probability of insulation failure between the pole 130 and the shell 110.

[0050] Although the material of the first high temperature resistant insulation layer 1117 can have multiple choices, for example, it can be ceramic, high molecular polymer, silicone rubber etc., but in the secondary battery 100 example of the utility model, the base material of the shell 110 is steel, for example, it can be carbon steel, stainless steel etc.. The composition of the first high temperature resistant insulation layer 1117 includes ceramic particles, and the ceramic particles are inorganic. It should be noted that the composition of the first high temperature resistant insulation layer 1117 can only include one kind of ceramic particles, or it can include multiple kinds of ceramic particles etc.. Since the ceramic material has the properties of high temperature resistance, corrosion resistance and aging resistance etc., the composition of the first high temperature resistant insulation layer 1117 includes ceramic particles, so as to ensure that the first high temperature resistant insulation layer 1117 has relatively stable insulation performance. At the same time, under the same roughness of the steel surface, the adhesion between the inorganic ceramic particles and the steel surface is better than that of the organic ceramic particles, therefore, in the embodiment, the ceramic particles adopt inorganic, which can increase the adhesion between the first high temperature resistant insulation layer 1117 and the surface of the end wall 111 of the shell 110, further reducing the probability of the first high temperature resistant insulation layer 1117 peeling off from the surface of the end wall 111, thereby being beneficial to further improving the insulation stability between the pole 130 and the shell 110.

[0051] Please refer toFigure 8 In the secondary battery 100 example, the end wall 111 includes a body portion 1112 and a recessed portion 1113, the recessed portion 1113 is arranged at the central region of the body portion 1112, and corresponds to the mounting position of the outer flange 133. The recessed portion 1113 is recessed towards the side of the electrode assembly 120, and includes a bottom wall 1114, the outer flange 133 abuts against the bottom wall 1114. Specifically, in the embodiment, when the upper plastic 160 and the sealing member 170 are arranged between the outer flange 133 and the end wall 111, the outer flange 133 abuts against the bottom wall 1114 through the upper plastic 160 and the sealing member 170. That is, the upper plastic 160 and the sealing member 170 are at least partially accommodated in the recessed portion 1113. The recessed portion 1113 is formed with a protrusion 1115 towards the side of the electrode assembly 120, the protrusion 1115 includes a top wall 1116 towards the side of the electrode assembly 120, the top wall 1116 abuts against the inner flange 132, and the first high-temperature-resistant insulation layer 1117 is arranged on the top wall 1116. It should be noted that when the lower plastic 150 is arranged inside the shell 110, the top wall 1116 abuts against the inner flange 132 through the lower plastic 150. The shape of the recessed portion 1113 can be a cylindrical shape, a multi-rib shape, or a cuboid, and optionally, in the embodiment, the recessed portion 1113 is a cylindrical structure, and the recessed portion 1113 is coaxially arranged with the end wall 111. Correspondingly, the top wall 1116 of the protrusion 1115 is a circular surface structure, and the pole post hole 1111 penetrates the top wall 1116 along the depth direction of the recessed portion 1113. By arranging the recessed portion 1113 on the end wall 111, on the one hand, on the outside of the shell 110, the recessed portion 1113 can reduce the mounting height of the outer flange 133 relative to the end wall 111, so that the height of the pole post 130 protruding outside the shell 110 can be reduced, and the overall height of the secondary battery 100 can be reduced. On the other hand, inside the shell 110, the arrangement of the protrusion 1115 can facilitate masking the region of the body portion 1112 around the protrusion 1115 when the first high-temperature-resistant insulation layer 1117 is applied, and the plating efficiency of the first high-temperature-resistant insulation layer 1117 arranged on the end wall 111 can be improved.

[0052] Optionally, please refer to 6 and Figure 7In the secondary battery 100 example of the utility model, the first high temperature resistant insulation layer 1117 is the insulation oxide layer formed on the surface of the end wall 111. The insulation oxide layer can be thermal oxidation layer, anodic oxidation layer, etc. Optionally, in the embodiment, the insulation oxide layer is anodic oxidation layer. Because the insulation oxide layer has the characteristics of high hardness and high insulation, the first high temperature resistant insulation layer 1117 can better meet the high temperature and high pressure use environment when thermal runaway. At the same time, because the insulation oxide layer has strong adhesion on the surface of the end wall 111, it will not cause phenomena such as ceramic coating peeling and powder falling, so setting the first high temperature resistant insulation layer as the insulation oxide layer can better ensure the stability of the insulation performance of the first high temperature resistant insulation layer, further reducing the probability of insulation failure between the pole 130 and the shell 110 when thermal runaway.

[0053] Please participate Figure 6 and Figure 7 In the secondary battery 100 example of the utility model, the thickness of the first high temperature resistant insulation layer 1117 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 the first high temperature resistant insulation layer 1117 is too thin, the adhesion strength between the first high temperature resistant insulation layer 1117 and the end wall 111 is low, and when the end wall 111 deforms, the first high temperature resistant insulation layer 1117 is easy to peel off from the surface of the end wall 111, and the insulation failure will occur at the peeling position, thereby causing the instability of the insulation effect of the first high temperature resistant insulation layer 1117. When the coating thickness of the first high temperature resistant insulation layer 1117 is too thick, it will occupy a large thickness space inside the shell 110, and the redundancy is too large, which not only increases the production cost of the first high temperature resistant insulation layer 1117, but also increases the overall quality of the secondary battery 100, which is not conducive to the improvement of the quality energy density of the secondary battery 100. In the embodiment, the thickness of the first high temperature resistant insulation layer 1117 is limited to 0.001-0.5mm, which not only can reduce the risk of the first high temperature resistant insulation layer 1117 peeling off from the end wall 111, ensure the stability of the insulation performance of the first high temperature resistant insulation layer 1117, but also can reduce the production cost of the first high temperature resistant insulation layer 1117, and reduce the influence on the overall quality of the secondary battery 100.

[0054] Although the pole 130 and the pole hole 1111 are not in direct contact in the normal working process of the secondary battery 100, the insulation member is prone to thermal melting in the event of thermal runaway, and the pole 130 is likely to be offset radially relative to the pole hole 1111 under the action of the internal pressure of the shell 110, so that the pole 130 comes into contact with the hole wall of the pole hole 1111, causing insulation failure between the pole 130 and the shell 110. In view of this, please refer to Figure 4 and Figure 5 In an example of the secondary battery 100 of the utility model, the hole wall of the pole hole 1111 is provided with a second high-temperature-resistant insulation layer 1118. The second high-temperature-resistant insulation layer 1118 is arranged on the entire hole wall of the pole hole 1111, and the second high-temperature-resistant insulation layer 1118 can be an insulation coating layer with the same material as the first high-temperature-resistant insulation layer 1117 or a different insulation coating layer from the first high-temperature-resistant insulation layer 1117. Optionally, in order to simplify the coating process, in the embodiment, the second high-temperature-resistant insulation layer 1118 is a coating material layer with the same material as the first high-temperature-resistant insulation layer 1117. In other embodiments, the second high-temperature-resistant insulation layer 1118 can also be an insulation oxide layer with the same material as the first high-temperature-resistant insulation layer 1117. By arranging the second high-temperature-resistant insulation layer 1118 on the hole wall of the pole hole 1111, the risk of insulation failure between the pole 130 and the end wall 111 caused by the contact between the pole 130 and the pole hole 1111 due to the offset of the pole 130 in the pole hole 1111 under thermal runaway can be prevented.

[0055] Please refer to Figure 4 , Figure 6 and Figure 7 In an example of the secondary battery 100 of the utility model, the side of the end wall 111 facing the outer flange 133 is provided with a third high-temperature-resistant insulation layer 1119, and the projection of the third high-temperature-resistant insulation layer 1119 on the end wall 111 covers the projection of the outer flange 133 on the end wall 111. The third high-temperature-resistant insulation layer 1119 can be a coating structure formed by coating a high-temperature-resistant insulation material on the surface of the end wall 111, such as a ceramic coating, an epoxy resin layer, etc. The third high-temperature-resistant insulation layer 1119 can also be an oxide insulation layer formed by anodizing the surface of the end wall 111, etc. The third high-temperature-resistant insulation layer 1119 can be a coating structure with the same material as the first high-temperature-resistant insulation layer 1117 or a coating structure with a different material from the first high-temperature-resistant insulation layer 1117. Optionally, in order to simplify the coating process, in the embodiment, the third high-temperature-resistant insulation layer 1119 is a coating structure with the same material as the first high-temperature-resistant insulation layer 1117. In other embodiments, the third high-temperature-resistant insulation layer 1119 can also be an insulation oxide layer with the same material as the first high-temperature-resistant insulation layer 1117.

[0056] In the radial direction of the pole column hole 1111, the minimum distance between the projected outer contour of the third high-temperature-resistant insulation layer 1119 and the projected outer contour of the outer flange 133 is d, and d≥(a-b) / 2. It should be noted that the projected outer contour of the third high-temperature-resistant insulation layer 1119 can be a circular contour, a square contour, a polygonal contour, etc., which is not limited. Optionally, in this embodiment, in order to facilitate the molding and positioning of the third high-temperature-resistant insulation layer 1119 on the end wall 111, the projected outer contour of the third high-temperature-resistant insulation layer 1119 is a circular contour, and is coaxially arranged with the pole column hole 1111.

[0057] In this embodiment, since the side of the end wall 111 facing the outer flange 133 is provided with the third high-temperature-resistant insulation layer 1119, even if the upper plastic 160 between the outer flange 133 and the end wall 111 is subjected to high temperature and is hot-melted or deformed, resulting in insulation failure, the third high-temperature-resistant insulation layer 1119 can continue to play an insulation role between the outer flange 133 and the end wall 111, thereby further reducing the probability of insulation failure between the pole 130 and the outer surface of the shell 110 in the case of thermal runaway. At the same time, the minimum distance between the projected outer contour of the third high-temperature-resistant insulation layer 1119 and the projected outer contour of the outer flange 133 is d, d≥(a-b) / 2. In this way, when the second insulation part 152 between the columnar part 131 and the pole column hole 1111 is hot-melted and detached, and the pole 130 has the maximum radial offset relative to the pole column hole 1111, the projected outer contour of the third high-temperature-resistant insulation layer 1119 can still cover the projection of the outer flange 133, and the third high-temperature-resistant insulation layer 1119 can always play an insulation role between the outer flange 133 and the end wall 111, thereby ensuring the insulation effect between the pole 130 and the outer surface of the shell 110 in the extreme case of complete hot-melting and detachment of the second insulation part 152.

[0058] Since the side surface of the end wall 111 away from the electrode assembly 120 needs to be welded with a current collector plate and other electrical connecting parts to realize the conductive connection between adjacent secondary batteries 100, a sufficient welding area needs to be reserved on the side surface of the end wall 111 away from the electrode assembly 120. Therefore, under the condition that the area of the third high-temperature-resistant insulation layer 1119 meets the insulation requirement between the outer flange 133 and the end wall 111, the maximum setting area of the third high-temperature-resistant insulation layer 1119 on the end wall 111 also needs to be limited as necessary. Based on this, optionally, please refer to Figure 7In the example of the secondary battery 100, the minimum distance between the projection outer contour of the third high-temperature-resistant insulation layer 1119 and the outer periphery of the end wall 111 in the radial direction of the pole hole 1111 is f, the diameter of the shell is D, and f is greater than or equal to (D-a) / 2. In this way, the maximum setting area of the third high-temperature-resistant insulation layer 1119 on the end wall 111 can be limited, so that the setting area of the third high-temperature-resistant insulation layer 1119 can meet the insulation requirement between the outer flange 133 and the end wall 111, and the side surface of the end wall 111 away from the electrode assembly 120 can also reserve sufficient welding area to meet the electrical connection requirement between adjacent secondary batteries 100. At the same time, the setting area of the third high-temperature-resistant insulation layer 1119 can also be prevented from being too large, thereby reducing the insulation cost.

[0059] Please refer to Figure 9 In an embodiment of the battery pack 200, the battery pack 200 includes a box body 210 and at least one secondary battery 100. The box body 210 includes a first box body part 211 and a second box body part 212, and the first box body part 211 and the second box body part 212 are mutually covered to form an accommodation space. A plurality of secondary batteries 100 are accommodated in the accommodation space, and the plurality of secondary batteries 100 can be connected in series and / or in parallel. The battery pack 200 can be, for example, a battery module, a battery pack, or the like.

[0060] 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, an electric planer, and the like. The electronic device 300 is not specially limited in the embodiments 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.

[0061] The secondary battery of the present application can reduce the probability of insulation failure between the pole and the shell of the parallelly connected secondary battery when thermal runaway occurs, reduce the risk of secondary short circuit between adjacent secondary batteries, and reduce the heat spreading phenomenon caused by thermal runaway. Meanwhile, the minimum distance between the projection outer contour of the first high-temperature-resistant insulation layer and the projection outer contour of the inner flange is c, the diameter of the pole hole is a, and the diameter of the columnar part is b, and c is greater than or equal to (a-b) / 2. In this way, when the second insulation part between the columnar part and the pole hole is thermally fused and separated, and the maximum radial offset of the pole relative to the pole hole occurs, the projection of the first high-temperature-resistant insulation layer can still cover the projection of the inner flange, thereby ensuring that the first high-temperature-resistant insulation layer can always play an insulation role between the inner flange and the end wall, so as to ensure the insulation effect between the pole and the shell in the extreme case that the second insulation part is completely thermally fused and separated.

[0062] 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 application relates to a secondary battery. The secondary battery comprises a shell, an electrode assembly arranged in the shell, and a pole fixed to an end wall of the shell and electrically connected to the electrode assembly. The pole comprises a columnar part, an outer flange and an inner flange, the outer flange and the inner flange are connected to two ends of the columnar part respectively, the columnar part penetrates through a pole hole of the end wall, the outer flange is located outside the shell, the inner flange is located inside the shell, and the end wall is clamped between the outer flange and the inner flange. The end wall is provided with a first high-temperature-resistant insulating layer on a side facing the inner flange, the first high-temperature-resistant insulating layer covers a projection of the inner flange on the end wall, and the minimum distance between the projection outer contour of the first high-temperature-resistant insulating layer and the projection outer contour of the inner flange in the radial direction of the pole hole is c, the diameter of the columnar part is b, and c is greater than or equal to (a-b) / 2. The surface roughness Ra of the area of the end wall corresponding to the first high-temperature-resistant insulating layer is 0.005-0.007 mm, and the surface roughness Rz is 0.015-0.045 mm.

2. The secondary battery according to claim 1, characterized by The base material of the shell is steel, and the first high-temperature-resistant insulating layer comprises ceramic particles which are inorganic substances.

3. The secondary battery according to claim 2, characterized by The end wall comprises a recess, the recess comprises a bottom wall, the outer flange abuts against the bottom wall, a side of the recess facing the electrode assembly is convex, the convex part comprises a top wall, and the first high-temperature-resistant insulating layer is arranged on the top wall.

4. The secondary battery according to claim 1, characterized by The first high-temperature-resistant insulating layer is an insulating oxide layer formed on the surface of the end wall.

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

6. The secondary battery according to claim 1, characterized by The hole wall of the pole hole is provided with a second high-temperature-resistant insulating layer.

7. The secondary battery according to any one of claims 1 to 6, characterized by The end wall is provided with a third high-temperature-resistant insulating layer on a side facing the outer flange, the third high-temperature-resistant insulating layer covers a projection of the outer flange on the end wall, the minimum distance between the projection outer contour of the third high-temperature-resistant insulating layer and the projection outer contour of the outer flange in the radial direction of the pole hole is d, and d is greater than or equal to (a-b) / 2.

8. The secondary battery according to claim 7, characterized by The minimum distance between the projection outer contour of the third high-temperature-resistant insulating layer and the outer periphery of the end wall in the radial direction of the pole hole is f, the diameter of the shell is D, and f is greater than or equal to (D-a) / 2.

9. The secondary battery according to claim 8, characterized by The application further relates to a secondary battery comprising any one of the secondary batteries according to claims 1-9.

10. A battery pack characterized by comprising: The application further relates to a battery pack comprising the battery according to claim 10.

11. An electronic device, comprising: ​

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