Secondary battery and electronic device
By wrapping heat-resistant insulating sheets in the upper and lower plastic layers of the secondary battery, the short-circuit problem during thermal runaway is solved, achieving an insulation effect that prevents short circuits even after thermal runaway, without adding assembly steps.
Patent Information
- Application Number
- CN202422785149.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-14
- Publication Date
- 2026-01-30
- Estimated Expiration
- 2034-11-14
AI Technical Summary
In the event of thermal runaway, the poor heat resistance of the plastic material in existing secondary batteries leads to the failure of insulation, causing short circuits between the positive and negative electrodes and heat propagation.
Heat-resistant insulating sheets are wrapped between the upper and lower plastic layers to prevent short circuits between the housing and the terminal in the event of thermal runaway. The design of the insulating sheets avoids additional assembly steps and maintains insulation function when subjected to external forces.
It effectively prevents the secondary battery from short-circuiting after thermal runaway, maintains insulation, avoids additional assembly steps, and can still maintain insulation function when the insulating sheet is crushed.
Smart Images
Figure CN223858157U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to a kind of secondary batteries and electronic devices. BACKGROUND
[0002] In the field of new energy power battery, the application of secondary battery is more and more widely, such as secondary battery (for example, lithium ion battery) can be applied to car, energy storage, mobile phone, tablet computer, wearable device, mobile power supply, electronic cigarette, digital product, electric tool, power device, energy storage device and other electronic devices. SUMMARY
[0003] In view of the problems in the related art, the utility model aims at providing a secondary battery and an electronic device to prevent short circuit of the secondary battery at least after thermal runaway of the secondary battery.
[0004] To achieve the above-mentioned purpose, the utility model provides a kind of secondary battery, comprising: shell, including end wall, end wall has first assembly hole;Upper plastic, with the upper surface of end wall facing the outside of shell contact, upper plastic has the second assembly hole corresponding with first assembly hole;Lower plastic, with the lower surface of end wall facing the inside of shell contact, lower plastic has the third assembly hole corresponding with first assembly hole;Pole, including cylindrical portion and outer flange and inner flange, cylindrical portion passes through first assembly hole, second assembly hole and third assembly hole, outer flange is connected with the one end of cylindrical portion located outside shell and with end wall together clamping upper plastic, inner flange is connected with the one end of cylindrical portion located inside shell and with end wall together clamping lower plastic;Wherein, upper plastic and lower plastic are respectively wrapped with heat-resistant insulating sheet, to prevent short circuit of shell and pole when upper plastic and / or lower plastic thermal runaway.
[0005] In some embodiments, the insulating sheet is a continuous piece or a segmented piece. In some embodiments, the edge of the insulating sheet is rounded.
[0006] In some embodiments, the lower plastic has a first portion contacting the lower surface, and a bending portion bent from the first portion towards a direction away from the inner flange, wherein the bending portion is at least partially inserted into the first assembly hole, the insulating sheet is at least partially inserted into the first assembly hole, the insulating sheet is the continuous piece and has a first transition portion provided at a transition between the bending portion and the first portion, wherein a radius of a transition round corner of the first transition portion is R, R is within a range of 0.3mm to 1.0mm, and a radius of a transition round corner of the inner flange corresponding to the first transition portion is equal to R.
[0007] In some embodiments, the insulating sheet is a segmented structure having a first segment and a second segment, wherein the first segment is arranged between the hole wall of the first assembly hole and the cylindrical portion, and the second segment is arranged between the end wall and the inner flange.
[0008] In some embodiments, the distance between the insulation sheet in the upper plastic and the edge of the upper plastic is greater than 0.02mm, and the distance between the insulation sheet in the lower plastic and the edge of the lower plastic is greater than 0.02mm.
[0009] In some embodiments, the thickness of the insulation sheet is greater than or equal to 0.2mm.
[0010] In some embodiments, in the axial direction of the columnar portion, the orthographic projection of the outer flange partially coincides with the orthographic projection of the insulation sheet in the upper plastic, wherein the distance between the first outer edge of the outer flange and the second inner edge of the insulation sheet in the upper plastic facing the columnar portion in the radial direction of the columnar portion is L1, and L1>1mm.
[0011] In some embodiments, in the axial direction of the columnar portion, the orthographic projection of the end wall partially coincides with the orthographic projection of the insulation sheet in the lower plastic, wherein the distance between the third outer edge of the insulation sheet in the lower plastic away from the columnar portion and the hole wall of the first assembly hole in the radial direction of the columnar portion is L2, and L2>1mm.
[0012] In some embodiments, in the radial direction of the columnar portion, the fourth outer edge of the inner flange encloses the insulation sheet in the lower plastic.
[0013] In some embodiments, the insulation sheet is a ceramic sheet.
[0014] Embodiments of the present application also provide an electronic device comprising the secondary battery of any one of the above.
[0015] The beneficial technical effects of the present application are at least:
[0016] The upper plastic and the lower plastic of the embodiments of the present application are respectively wrapped with heat-resistant insulation sheets, so as to prevent the shell and the pole from short-circuiting when the upper plastic and / or the lower plastic are out of control, and at least after the secondary battery is out of control, there is an insulation effect between the positive and negative electrodes to prevent the secondary battery from short-circuiting. Moreover, since the upper plastic and the lower plastic are wrapped with heat-resistant insulation sheets, at least no additional assembly steps are added. Furthermore, since the insulation sheets are wrapped inside the upper plastic and the lower plastic, even if the insulation sheets are crushed by external force, the insulation function of the insulation sheets is not affected. BRIEF DESCRIPTION OF DRAWINGS
[0017] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings in the following description are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.
[0018] Figure 1A partial cross-sectional view of a prior art secondary battery is shown.
[0019] Figure 2 A secondary short circuit test schematic is shown.
[0020] Figure 3 A schematic of an electronic device according to an embodiment of the application is shown.
[0021] Figure 4 A perspective view of a secondary battery according to an embodiment of the application is shown.
[0022] Figure 5 A partial cross-sectional view of a secondary battery according to an embodiment of the application is shown.
[0023] Figure 6 A partial cross-sectional view of a secondary battery according to another embodiment of the application is shown. DETAILED DESCRIPTION
[0024] For a better understanding of the spirit of the embodiments of the present application, the following further describes the same in connection with the preferred embodiments of the present application.
[0025] Embodiments of the present application will be described in detail below. Throughout the specification, the same or similar components and components having the same or similar functions are denoted by like reference numerals. The embodiments described herein with reference to the accompanying drawings are illustrative in nature, diagrammatic and serve to provide a basic understanding of the present application. The embodiments of the present application should not be construed as limiting the present application.
[0026] As used herein, the terms "approximately," "substantially," "about," and "generally" are used to describe and account for small variations. When utilized in connection with an event or circumstance, such terms can refer to instances in which the event or circumstance occurs exactly, and instances in which the event or circumstance occurs with a close approximation.
[0027] In this specification, unless specifically specified or limited, relative terms such as "central," "longitudinal," "lateral," "forward," "rearward," "rightward," "leftward," "internal," "external," "lower," "upper," "horizontal," "vertical," "above," "below," "top," "bottom," and derivatives thereof (e.g., "horizontally," "downwardly," "upwardly," etc.) should be construed to refer to the orientation as then described or as shown in the drawing under discussion. These relative terms are for convenience of description only and do not require that the application be practiced with the particular orientation described or shown.
[0028] For ease of description, "first", "second", "third", and the like can be used herein to distinguish between different components of one figure or series of figures. The "first", "second", "third", and the like are not intended to describe the corresponding components.
[0029] Figure 1 A partial cross-sectional schematic diagram of a prior art secondary battery is shown, see Figure 1 wherein the secondary battery 1 is shown to include an upper plastic 2, a pole 3, a lower plastic 4, and a sealing ring 5. For the prior art secondary battery 1 positive pole side design, currently basically Al pole 3, upper plastic 2, sealing ring 5 and lower plastic 4 are used, or Al pole 3 and an integrated plastic form are used, and the upper plastic 2 and the lower plastic 4 are mostly PFA / PBT / PPS / PP / LCP / ECM engineering plastics, which play an insulating role of isolating the positive and negative poles. However, for the current plastic material, the melting point is not enough, and the heat resistance is poor. In the Pack level multi-cell parallel thermal runaway test, the plastic material melts, burns, and carbonizes, the plastic loses the insulation effect, triggers the positive and negative poles of the cell to contact, the parallel cells short circuit, a secondary short circuit is formed, and thermal propagation is caused. Figure 2 A secondary short circuit test schematic diagram is shown, see Figure 2 The trigger cell 7 is connected in parallel with the parallel cell 8, and through the needle 6, it is tested whether the trigger cell 7 will cause the parallel cell 8 to short circuit after thermal runaway, form a secondary short circuit, and cause thermal propagation.
[0030] The utility model provides a kind of electronic device 1000, in some embodiments, electronic device 1000 can include battery pack, battery pack 1002, electric vehicle, energy storage cabinet etc., the following embodiment is for the convenience of explanation, with electronic device 1000 as vehicle for example to explain. Figure 3 A schematic diagram of the electronic device of the embodiment of the application as a vehicle is shown, see Figure 3The vehicle is provided with another electronic device 1000, which can be a battery pack 1002. The battery pack 1002 can be arranged at the bottom, head or tail of the vehicle body 1001. The battery pack 1002 can be used for power supply of the vehicle, for example, the battery pack 1002 can be used as the operating power supply of the vehicle. The working part of the electronic device 1000 is electrically connected with the battery pack 1002 to obtain power support. 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 automobile or an extended range automobile, but is not limited thereto. The working part is the vehicle body, the battery pack 1002 is arranged at the bottom of the vehicle body, and provides power support for driving of the vehicle or operation of electrical elements in the vehicle. However, in some other embodiments, the electronic device 1000 can also be a mobile phone, a portable device, a notebook computer, a ship, a spacecraft, an electric toy and an electric tool, etc. The spacecraft includes an airplane, a rocket, a space shuttle and a spacecraft, etc. The working part can obtain power from the battery pack 1002, and make corresponding working unit parts, such as a fan blade rotating unit, a dust collection working unit of a dust collector, etc. The electric toy includes a fixed or mobile electric toy, such as a game machine, an electric automobile toy, an electric ship toy and an electric airplane toy, etc. 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, etc. The electronic device 1000 is not specially limited in the embodiments of the present application.
[0031] Figure 4 A perspective view of a secondary battery according to an embodiment of the present application is shown, Figure 5 A partial cross-sectional view of a secondary battery according to an embodiment of the present application is shown, Figure 6 A partial cross-sectional view of a secondary battery according to another embodiment of the present application is shown. Referring to Figure 4 and Figure 5The embodiments of the present application provide a secondary battery 100, which comprises a shell 200, an electrode assembly located in the shell 200, and a current collector plate and a pole 50 assembled on the shell 200. The shell 200 comprises an end wall 111 and a side wall surrounding the end wall 111. The shell 200 can be formed in various ways as long as a stable sealing and electrical connection relationship can be formed, for example, in the form of one-piece stamping, one-piece casting or separate welding. The shell 200 is formed with a receiving cavity for accommodating the electrode assembly, electrolyte, current collector plate and other necessary components of the battery. Specifically, the diameter of the shell 200 can be determined according to the specific size of the electrode assembly. The material of the shell 200 can be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent the shell 200 from rusting during long-term use, a layer of anti-rust material such as metal nickel can also be plated on the surface of the shell 200. The secondary battery 100 can be a cylindrical battery, for example, a 4680 cylindrical battery with a height of 80 mm and a diameter of 46 mm; for example, a height of 15 mm and a diameter of 46 mm.
[0032] The electrode assembly is a component in which electrochemical reactions occur in the secondary battery 100. One or more electrode assemblies can be contained within the case 200. The electrode assembly is a jelly-roll or stacked electrode assembly including a positive electrode tab including a positive electrode current collector and a positive electrode active material layer coated on the positive electrode current collector, a first separator, a negative electrode tab including a negative electrode current collector and a negative electrode active material layer coated on the negative electrode current collector, and a second separator, the positive electrode current collector having a first coated region coated with the positive electrode active material layer and a first uncoated region not coated with the positive electrode active material layer formed thereon, the first coated region and the first uncoated region being arranged in a height direction of the electrode assembly, the first uncoated region extending to outside of the separator toward one end in the height direction of the secondary battery 100 and forming a bent positive electrode tab, the second coated region coated with the negative electrode active material layer and the second uncoated region not coated with the negative electrode active material layer being formed on the negative electrode current collector, the second coated region and the second uncoated region being arranged in the height direction of the electrode assembly, the second uncoated region also extending to outside of the separator toward one end in the height direction of the secondary battery 100 and forming a bent negative electrode tab, the first separator and the second separator being disposed between the positive electrode tab and the negative electrode tab to isolate the positive electrode active material layer and the negative electrode active material layer. In the case of a lithium ion secondary battery 100, the material of the positive electrode current collector 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. The material of the negative electrode current collector 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. The base material of the first separator and the second separator can be PP (polypropylene), PE (polyethylene), or the like. To protect and insulate the electrode assembly, an insulating film can be wrapped around the outside of the electrode assembly, and the insulating film can be synthesized from PP, PE, PET, PVC, or other high-molecular polymer materials.
[0033] Reference Figure 5In some embodiments, the end wall 111 has a first assembly hole 1110, the upper plastic 121 contacts a surface of the end wall 111 facing outside of the housing 200, the lower plastic 131 contacts a surface of the end wall 111 facing inside of the housing 200, the upper plastic 121 has a second assembly hole 1210 corresponding to the first assembly hole 1110, and the lower plastic 131 has a third assembly hole 1310 corresponding to the first assembly hole 1110 and the second assembly hole 1210. In some embodiments, the pole column 50 includes an outer flange 51, a columnar portion 52, and an inner flange 53, the outer flange 51 is located outside of the housing 200, and the columnar portion 52 passes through the first assembly hole 1110, the second assembly hole 1210, and the third assembly hole 1310. The outer flange 51 is connected to one end of the columnar portion 52 of the pole column 50 located outside of the housing 200, the inner flange 53 is connected to one end of the columnar portion 52 of the pole column 50 located inside of the housing 200, and the inner flange 53 and the end wall 111 jointly hold the lower plastic 131, and the outer flange 51 and the end wall 111 jointly hold the upper plastic 121. The inner flange 53 of the pole column 50 contacts a surface of the lower plastic 131 facing the electrode assembly / backing away from the end wall 111 and fixes the lower plastic 131 to an inner side surface of the end wall 111 facing inside of the housing 200, the outer flange 51 of the pole column 50 contacts a surface of the upper plastic 121 backing away from the end wall 111 and fixes the lower plastic 131 to an outer side surface of the end wall 111 facing away from the inside of the housing 200, and the upper plastic 121 and the lower plastic 131 surround the columnar portion 52. In some embodiments, the upper plastic 121 and the lower plastic 131 are respectively wrapped with heat-resistant insulation sheets 141 to prevent the housing 200 and the pole column 52 from short-circuiting when the upper plastic 121 and / or the lower plastic 131 are out of control. Because the plastic material melts, burns, and carbonizes, the upper plastic 121 and the lower plastic 131 lose their insulation effect, triggering the positive and negative electrodes of the secondary battery 100 to contact, causing a short circuit. By providing the heat-resistant insulation sheets 141 inside the upper plastic 121 and the lower plastic 131, at least the positive and negative electrodes can be insulated after the secondary battery 100 is out of control, effectively preventing the secondary battery 100 from short-circuiting. In some embodiments, the upper plastic 121 and the lower plastic 131 wrapped with the heat-resistant insulation sheets 141 do not increase at least an additional assembly step. Further, it can be understood that the upper plastic 121 and the lower plastic 131 wrapped with the heat-resistant insulation sheets 141 can be an integrated structure. It can be understood that the heat-resistant insulation sheets 141 are easily crushed when directly contacting the pole column 50, but because the insulation sheets 141 are wrapped inside the upper plastic 121 and the lower plastic 131, even if the insulation sheets 141 are crushed by external forces, it does not affect the insulation function of the insulation sheets 141. In some embodiments, the edges of the insulation sheets 141 are rounded, which can at least effectively prevent the edges of the insulation sheets 141 from scratching the upper plastic 121 and the lower plastic 131, thereby exposing the insulation sheets 141 to the surfaces of the upper plastic 121 and the lower plastic 131 and causing foreign matter.In some embodiments, the lower plastic 131 has a first portion 1311 contacting the lower surface, and a bending portion 1313 bending from the first portion 1311 in a direction away from the inner flange 53, the bending portion 1313 is at least partially inserted into the first assembly hole 1110, and the insulating sheet 141 is at least partially inserted into the first assembly hole 1110. It can be understood that for the pole 50, not only the inner and outer surfaces of the shell 200 and the pole 50 should be prevented from contacting when the secondary battery 100 is in thermal runaway, but also the hole wall of the first assembly hole 1110 should be prevented from contacting the pole 50 to cause short circuit. The insulating sheet 141 provided in the lower plastic 131 needs to not only prevent the inner flange 53 from contacting the inner surface of the end wall 111, but also further prevent the inner wall of the first assembly hole 1110 from contacting the cylindrical portion of the pole 50. In some embodiments, the insulating sheet 141 has a first transition portion 1411 provided at a transition portion 1312 between the bending portion 1313 and the first portion 1311, wherein a radius of a transition round corner of the first transition portion 1411 is R, R is within a range of 0.3mm to 1.0mm, and a radius of a transition round corner of the inner flange 53 corresponding to the first transition portion 1411 is equal to R, at least avoiding that the R angle size is too large or too small or the transition round corner of the first transition portion 1411 does not match the size of the transition round corner of the inner flange 53 corresponding to the first transition portion 1411, so that the insulating sheet 141 is broken. The insulating sheet 141 has the first transition portion 1411 provided at the transition portion 1312 between the bending portion 1313 and the first portion 1311, that is, the insulating sheet 141 can be a continuous piece with the first transition portion 1411 having an intermediate bending. In some embodiments, a distance between the insulating sheet 141 located in the upper plastic 121 and an edge of the upper plastic 121 is greater than 0.02mm, and a distance between the insulating sheet 141 located in the lower plastic 131 and an edge of the lower plastic 131 is greater than 0.02mm, and the molding of the upper plastic 121 and the lower plastic 131 is more advantageous within this distance. In some embodiments, the thickness of the insulating sheet 141 is greater than or equal to 0.2mm, at least avoiding that the insulating sheet 141 is too thin and is easy to break, and the insulating sheet 141 is not easy to mold, and the yield of the upper and lower plastics wrapped with the insulating sheet 141 is improved. In some embodiments, in an axial direction of the cylindrical portion 52, an orthographic projection of the outer flange 51 partially overlaps an orthographic projection of the insulating sheet 141 in the upper plastic 121, wherein a distance between a first outer edge 511 of the outer flange 51 and a second inner edge 1412 of the insulating sheet 141 in the upper plastic 121 facing the cylindrical portion 52 in a radial direction of the cylindrical portion 52 is L1, and as a priority, L1>1mm, at least making the insulating sheet 141 located in the upper plastic 121 still block the contact between the outer flange 51 of the pole 50 and the shell 200 after the insulation failure of the upper plastic 121, for example, carbonization.In some embodiments, in the axial direction of the columnar portion 52, the orthographic projection of the end wall 111 partially coincides with the orthographic projection of the insulating sheet 141 in the lower plastic 131. In the radial direction of the columnar portion 52, the distance between the insulating sheet 141 in the lower plastic 131 away from the third outer edge 1413 of the columnar portion 52 and the hole wall of the first mounting hole 1110 is L2, where L2>1mm. This ensures that even after the insulation of the lower plastic 131 fails, for example, due to carbonization, the insulating sheet 141 in the lower plastic 131 can still prevent the contact between the inner flange 53 of the pole post 50 and the end wall 111 of the housing 200. In some embodiments, the fourth outer edge 534 of the inner flange 53 in the radial direction of the columnar portion 52 surrounds the insulating sheet 141 located within the lower plastic 131. That is, the insulating sheet 141 located within the lower plastic 131 does not extend beyond the fourth outer edge 534 of the inner flange 53, thereby preventing the insulating sheet 141 from extending beyond the fourth outer edge 534 of the inner flange 53. Where the insulating sheet 141 extends beyond the fourth outer edge 534, a stress point is formed, making the insulating sheet 141 more prone to breakage. The sharp fragments of the broken insulating sheet 141 can easily pierce the lower plastic 131, causing foreign objects to fall out and affecting the service life of the secondary battery 100. In some embodiments, the distance between the fourth outer edge 534 and the third outer edge 1413 in the radial direction of the columnar portion 52 is L3. Preferably, L3 is within the range of 1mm-3mm.
[0034] Insulating sheet 141 can be a ceramic sheet, see reference. Figure 6 , Figure 6 A partial cross-sectional schematic diagram of a secondary battery according to another embodiment of this application is shown. Figure 6 In the middle, the secondary battery 100 has the same characteristics as... Figure 5 The structure is similar to that of the secondary battery 100, and... Figure 5 The difference between the secondary battery 100 and the secondary battery is that... Figure 6 The insulating sheet 141 located within the lower plastic 131 has a segmented structure with a first segment 1418 and a second segment 1419. The first segment 1418 is disposed between the wall of the first mounting hole 1110 and the columnar portion 52, and the second segment 1419 is disposed between the end wall 111 and the inner flange 53. That is to say, compared to... Figure 5 The insulating sheet 141 shown in the figure, Figure 6 The middle insulating sheet 141 does not include the first transition portion 1411 with a middle bend. The insulating sheet 141 configured in this way at least retains the function of preventing the housing 200 from short-circuiting with the pole post 52 in the event of thermal runaway of the upper plastic 121 and / or lower plastic 131, while avoiding the first transition portion 1411 from being broken by stress.
[0035] Embodiments of the present application also provide an electronic device 1000 comprising the secondary battery 100 of any one of the above, and the electronic device 1000 can have the beneficial effects described above with respect to the secondary battery 100.
[0036] It can be understood that in some embodiments, the electronic device 1000 of the present application can be a battery pack comprising a plurality of secondary batteries 100 connected in parallel, the secondary battery 100 being any one of the above, and the battery pack can have the beneficial effects described above with respect to the secondary battery 100, in addition, the battery pack using a plurality of secondary batteries 100 connected in parallel can at least avoid the melting, burning and carbonization of the plastic material, the loss of insulation of the upper plastic 121 and the lower plastic 131, the contact of the positive and negative electrodes of the secondary battery 100, so that the plurality of secondary batteries 100 connected in parallel are short-circuited, forming a secondary short circuit, causing heat spread.
[0037] The above merely describes preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can be variously changed and modified. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.
Claims
1. A secondary battery characterized by comprising: The application relates to a shell, comprising an end wall having a first assembly hole; an upper plastic in contact with an upper surface of the end wall facing the outside of the shell, the upper plastic having a second assembly hole corresponding to the first assembly hole; a lower plastic in contact with a lower surface of the end wall facing the inside of the shell, the lower plastic having a third assembly hole corresponding to the first assembly hole; and a pole comprising a columnar portion and an outer flange and an inner flange, the columnar portion passing through the first assembly hole, the second assembly hole and the third assembly hole, the outer flange being connected to one end of the columnar portion located outside the shell and clamping the upper plastic together with the end wall, and the inner flange being connected to one end of the columnar portion located inside the shell and clamping the lower plastic together with the end wall; wherein the upper plastic and the lower plastic are respectively wrapped with heat-resistant insulation sheets to prevent the shell and the pole from short-circuiting when the upper plastic and / or the lower plastic is out of control. The insulation sheet is a continuous piece or a segmented piece. The edge of the insulation sheet is rounded. The lower plastic has a first part in contact with the lower surface and a bending part bent from the first part towards a direction away from the inner flange, wherein the bending part is at least partially inserted into the first assembly hole, the insulation sheet is at least partially inserted into the first assembly hole, the insulation sheet is the continuous piece and has a first transition part provided at a transition part between the bending part and the first part, wherein the radius of the transition round corner of the first transition part is R, the R is within the range of 0.3mm to 1.0mm, and the radius of the transition round corner of the inner flange corresponding to the first transition part is equal to the R. The insulation sheet is a segmented piece having a first segment and a second segment, wherein the first segment is arranged between the hole wall of the first assembly hole and the columnar portion, and the second segment is arranged between the end wall and the inner flange.
2. The secondary battery according to claim 1, characterized by The distance between the edge of the upper plastic and the insulation sheet located in the upper plastic is greater than 0.02mm, and the distance between the edge of the lower plastic and the insulation sheet located in the lower plastic is greater than 0.02mm.
3. The secondary battery according to claim 1, characterized by The thickness of the insulation sheet is greater than or equal to 0.2mm.
4. The secondary battery according to claim 2, characterized by In the axial direction of the columnar portion, the orthographic projection of the outer flange partially coincides with the orthographic projection of the insulation sheet in the upper plastic, wherein the distance between the first outer edge of the outer flange and the second inner edge of the insulation sheet in the upper plastic towards the columnar portion in the radial direction of the columnar portion is L1, and L1>1mm. In the axial direction of the columnar portion, the orthographic projection of the end wall partially coincides with the orthographic projection of the insulation sheet in the lower plastic, wherein in the radial direction of the columnar portion, the distance between the third outer edge of the insulation sheet in the lower plastic away from the columnar portion and the hole wall of the first assembly hole is L2, and L2>1mm.
5. The secondary battery according to claim 2, characterized by In the radial direction of the columnar portion, the fourth outer edge of the inner flange surrounds the insulation sheet located in the lower plastic.
6. The secondary battery according to claim 1, characterized by The insulation sheet is a ceramic sheet.
7. The secondary battery according to claim 1, characterized by 8. The secondary battery according to claim 1, characterized by 9. The secondary battery according to claim 1, characterized by 10. The secondary battery according to claim 1, characterized by 11. The secondary battery according to any one of claims 1-10, characterized in that, 12. An electronic device, comprising: The secondary battery according to any one of claims 1 to 11 is included.