Secondary battery, battery pack, and electronic device

Abstract

The utility model provides a secondary battery, comprising: a housing comprising an end wall and a side wall surrounding the end wall, the end wall having a first assembly hole; the lower plastic is provided with a second assembly hole corresponding to the first assembly hole, the surface, facing the end wall, of the lower plastic comprises a plane surrounding the second assembly hole and an inclined plane surrounding and connected with the plane, the plane makes contact with the surface, facing the interior of the shell, of the end wall, and the inclined plane makes contact with the second assembly hole along with increasing of the distance between the inclined plane and the second assembly hole. The distance between the inclined surface and the end wall is increased; the pole comprises a columnar part and an inner flange, the columnar part penetrates through the first assembly hole and the second assembly hole, and the inner flange is connected with one end, located in the shell, of the columnar part and clamps the lower plastic together with the end wall. The utility model aims to provide a secondary battery, a battery pack and an electronic device so as to at least improve the safety of the secondary battery.

Description

TECHNICAL FIELD

[0001] The utility model relates to a kind of secondary batteries, battery pack and electronic device. BACKGROUND

[0002] In the field of new energy power battery, secondary battery generally includes electrode assembly, shell, cover plate and the like. Electrode assembly includes positive pole sheet, negative pole sheet and diaphragm between positive pole sheet and negative pole sheet, these positive pole sheet, negative pole sheet and diaphragm are wound into electrode assembly after mutual stacking, then encapsulated in shell. Under the general circumstances, lower plastic is arranged between electrode assembly and the end wall of shell, for preventing electrode assembly from moving, and play the role of insulation. SUMMARY

[0003] In view of the problems in the related art, the utility model aims to provide a secondary battery, battery pack and electronic device, to at least improve the safety of secondary battery.

[0004] To achieve the above object, the utility model provides a kind of secondary battery, comprising: shell, including end wall and the side wall around end wall, end wall has first assembly hole;Lower plastic has the second assembly hole corresponding with first assembly hole, the surface of lower plastic towards end wall includes the plane around second assembly hole, and the inclined surface around and connecting plane, plane is in contact with the surface of end wall towards the inside of shell, with the distance between inclined surface and second assembly hole increases, the distance between inclined surface and end wall increases;Pole, including columnar portion and inner flange, columnar portion passes through first assembly hole and second assembly hole, inner flange is connected with the one end of columnar portion in the inside of shell and is held lower plastic with end wall.

[0005] In some embodiments, there is a gap between the outer edge of the lower plastic and the side wall.

[0006] In some embodiments, in the direction from the end wall to the lower plastic, the lower plastic does not exceed the inner flange of the pole, and the included angle between the inclined surface and the end wall is within the range of 1° to 30°.

[0007] In some embodiments, the lower plastic is provided with a through hole at the inclined surface, which penetrates the thickness direction of the lower plastic.

[0008] In some embodiments, the distance between the inner flange and the inclined surface is greater than 2mm, and the lower plastic is also provided with a through hole at the plane.

[0009] In some embodiments, the inclined surface of the lower plastic is provided with a reinforcing rib protruding towards the end wall.

[0010] In some embodiments, the lower plastic includes a flat portion corresponding to the flat surface and an inclined portion corresponding to the inclined surface, the inclined portion as a whole is inclined relative to the flat portion in a direction away from the end wall, or the surface of the lower plastic facing the inside of the casing is a flat surface.

[0011] In some embodiments, the lower plastic includes a weak portion disposed at a position between the flat surface and the inclined surface, at least part of the weak portion has a thickness smaller than a thickness of the lower plastic at the flat surface or at the inclined surface.

[0012] Embodiments of the present application also provide a battery pack including the secondary battery of any one of the above.

[0013] Embodiments of the present application also provide an electronic device including the battery pack.

[0014] The beneficial technical effects of the present application are as follows:

[0015] The surface of the lower plastic of the embodiments of the present application facing the end wall includes a flat surface and an inclined surface surrounding and connecting the flat surface, as the distance between the inclined surface and the second assembly hole increases, the distance between the inclined surface and the end wall increases, that is, the inclined surface does not fit with the end wall, and the inclined surface is inclined in a direction away from the end wall, so as to discharge the electrolyte between the lower plastic and the casing along the inclined surface in the direction of the electrode assembly, avoiding the electrolyte gathering between the lower plastic and the casing to cause liquid phase corrosion, resulting in the inside of the casing being blackened or rusted, reducing the strength of the casing, and improving the safety of the secondary battery. BRIEF DESCRIPTION OF DRAWINGS

[0016] 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 other drawings can also be obtained by those skilled in the art without creative labor.

[0017] Figure 1 Part of the sectional view of the secondary battery of the prior art is shown.

[0018] Figure 2 The perspective view of the lower plastic of the prior art is shown.

[0019] Figure 3 The surface of the lower plastic of the prior art facing the electrode assembly is shown.

[0020] Figure 4 The schematic view of the electronic device of the embodiments of the present application when the electronic device is a vehicle is shown.

[0021] Figure 5 The perspective view of the secondary battery according to the embodiments of the present application is shown.

[0022] Figure 6 A plan view of the secondary battery is shown.

[0023] Figure 7 A cross-sectional view taken along AA line of Figure 6 is shown.

[0024] Figure 8 An enlarged view of a portion of Figure 7 on which the positive pole is located is shown.

[0025] Figure 9 A side of the bottom surface of the lower plastic according to the first embodiment of the present application is shown.

[0026] Figure 10 A cross-sectional view taken along BB line of Figure 9 is shown.

[0027] Figure 11 A side of the bottom surface of the lower plastic according to the second embodiment of the present application is shown.

[0028] Figure 12 A cross-sectional view taken along CC line of Figure 11 is shown.

[0029] Figure 13 A side of the bottom surface of the lower plastic according to the third embodiment of the present application is shown.

[0030] Figure 14 A cross-sectional view taken along DD line of Figure 13 is shown.

[0031] Figure 15 A side of the bottom surface of the lower plastic according to the fourth embodiment of the present application is shown.

[0032] Figure 16 A cross-sectional view taken along EE line of Figure 15 is shown. DETAILED DESCRIPTION

[0033] For a better understanding of the spirit of the embodiments of the present application, the following further describes the embodiments of the present application in combination with some preferred embodiments of the present application.

[0034] The embodiments of the present application will be described in detail below. In the entire description of the present application, the same or similar components and components having the same or similar functions are denoted by similar reference numerals. The embodiments described herein with respect to the accompanying drawings are of illustrative nature, diagrammatic nature and for providing a basic understanding of the present application. The embodiments of the present application should not be interpreted as a limitation of the present application.

[0035] As used herein, the terms "approximately," "about," "substantially" and "near" 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 is occurring exactly as well as instances in which the event or circumstance is occurring approximately or near.

[0036] In this description, 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 intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures.

[0037] For purposes of this description, "first," "second," "third," etc. can be used interchangeably to distinguish one element from another in a set of elements. "First," "second," "third," etc. are not intended to denote an order or a ranking.

[0038] Figure 1 A portion of a cross-sectional view of a prior art secondary battery is shown, Figure 2 A perspective view of a prior art lower plastic 1 is shown, in which the surface facing the case 2 (material is generally steel) is shown, which is a flat surface. Figure 3 A surface of the prior art lower plastic 1 facing the electrode assembly (JR) is shown. The assembly process of the secondary battery includes: placing the lower plastic 1 into the case, then assembling the pole post (material is generally aluminum) to the lower plastic 1 and the case, and then clamping the lower plastic 1 to the case by riveting of the pole post. Considering the volume utilization rate of the secondary battery, the prior art lower plastic 1 is generally arranged to be in close contact with the case. However, during the riveting process, the pole post will extrude the lower plastic 1 in the radial direction, causing the edge of the lower plastic 1 to possibly abut against the case, that is, the center of the lower plastic 1 is subjected to a force radially outward, and the edge of the lower plastic 1 is subjected to a force radially inward, causing a portion of the lower plastic 1 to generate a downward concave deformation. The lower plastic 1 is a solid sheet, and a containing cavity for accumulating electrolyte is easily formed at the deformed position. During the liquid injection process, the secondary battery is placed in a direction with the pole post downward, and liquid injection is performed from the end of the secondary battery opposite to the pole post. At this time, the lower plastic 1 is located at the lowermost position in the case, and the electrolyte will seep into the space between the lower plastic 1 and the case, causing corrosion of the case due to accumulation of the electrolyte. Due to the deformation concave of the lower plastic 1, more electrolyte is accumulated between the lower plastic 1 and the case, and after the secondary battery is used for a period of time, concentrated liquid-phase corrosion of the case is intensified.

[0039] The utility model provides a kind of electronic device 1000, the following embodiment is for the convenience of explanation, with electronic device 1000 as vehicle is explained by example. Refer to Figure 4 , the inside of vehicle is provided with battery pack 1002, battery pack 1002 can be arranged at the bottom or head or tail of vehicle body 1001. Battery pack 1002 can be used for the power supply of vehicle, for example, battery pack 1002 can be used as the operating power supply of vehicle. The working part of electronic device 1000 is electrically connected with battery pack 1002, to obtain electric energy support. Vehicle can be fuel automobile, gas automobile or new energy automobile, and new energy automobile can be pure electric vehicle, hybrid electric vehicle or extended range vehicle, but not limited to this. Working part is vehicle body, and battery pack 1002 is arranged at the bottom of vehicle body, and provides electric energy support for the running of vehicle or the operation of electrical element in vehicle. However, in other some embodiments, electronic device 1000 can also be mobile phone, portable device, notebook computer, ship, spacecraft, electric toy and electric tool and so on. Spacecraft includes airplane, rocket, space shuttle and spacecraft and so on, and working part can obtain the electric energy of battery pack 1002, and makes corresponding working unit component, for example, fan blade rotating unit of fan, dust absorption working unit of dust collector and so on. Electric toy includes fixed or mobile electric toy, for example, game machine, electric car toy, electric ship toy and electric plane toy and so on. Electric tool includes metal cutting electric tool, grinding electric tool, assembly electric tool and railway electric tool, for example, electric drill, electric grinder, electric wrench, electric screwdriver, electric hammer, impact drill, concrete vibrator and electric planer and so on. The above electronic device 1000 is not specially limited in the embodiment of the application.

[0040] Figure 5 A perspective view of a secondary battery 100 according to an embodiment of the present application is shown, Figure 6 A top view of the secondary battery 100 is shown, Figure 7 A cross-sectional view taken along AA line of Figure 6 is shown, in which the electrode assembly and other components inside the case 200 are omitted, Figure 8 A cross-sectional view taken along BB line of Figure 7Figure 2 is an enlarged view of the portion of the secondary battery 100 on the side of the positive electrode post 50. The embodiment of the present application provides a secondary battery 100, which includes a housing 200, a lower plastic 30 located in the housing 200, an electrode assembly, a current collector, a post 50, such as a positive electrode post, assembled on the housing 200 and the lower plastic 30. The housing 200 includes an end wall 111 and a side wall 112 surrounding the end wall 111, the end wall 111 having a first assembly hole 1110; the lower plastic 30 has a second assembly hole 300 corresponding to the first assembly hole 1110; the post 50 includes an outer flange 53, a columnar portion 51, and an inner flange 52, the outer flange 53 being located outside the housing 200, the columnar portion 51 passing through the first assembly hole 1110 and the second assembly hole 300, the columnar portion 51 of the post 50 being connected to one end of the outer flange 53 located outside the housing 200, the inner flange 52 being connected to one end of the outer flange 53 located inside the housing 200, and the inner flange 52 clamping the lower plastic 30 together with the end wall 111, the inner flange 52 of the post 50 contacting a surface of the lower plastic 30 facing the electrode assembly / the surface (hereinafter referred to as the top surface 31) of the end wall 111, and fixing the lower plastic 30 to the inner side surface of the end wall 111 facing the inside of the housing 200.

[0041] 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 be cylindrical or prismatic, or can be any other closed-loop profile that can be matched with the end wall. The housing 200 has a receiving cavity for receiving the electrode assembly, electrolyte, lower plastic 30, current collector, and other necessary components of the battery. Specifically, the diameter of the housing 200 can be determined according to the size of the electrode assembly. The material of the housing 200 can be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent rusting of the housing 200 during long-term use, a layer of anti-rust material such as metal nickel can be plated on the surface of the housing 200. The secondary battery 100 can be a cylindrical battery, such as a 4680 cylindrical battery with a height of 80 mm and a diameter of 46 mm, or a cylindrical battery with a height of 15 mm and a diameter of 46 mm.

[0042] The electrode assembly is a component in which electrochemical reactions occur in the secondary battery 100. One or more electrode assemblies can be included in 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 area coated with the positive electrode active material layer and a first uncoated area not coated with the positive electrode active material layer formed thereon, the first coated area and the first uncoated area being arranged in a height direction of the electrode assembly, the first uncoated area 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 area coated with the negative electrode active material layer and the second uncoated area not coated with the negative electrode active material layer being formed on the negative electrode current collector, the second coated area and the second uncoated area being arranged in the height direction of the electrode assembly, the second uncoated area 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 separate 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. In order to protect and insulate the electrode assembly, an insulating film can also be coated on the outside of the electrode assembly, and the insulating film can be synthesized from PP, PE, PET, PVC, or other high-molecular polymer materials.

[0043] Figure 9 and Figure 10 , Figure 11 and Figure 12 , Figure 13 and Figure 14 , Figure 15 and Figure 16 respectively show the lower plastic 30 according to the first embodiment to the fourth embodiment of the present application.

[0044] Figure 9 shows one side of the bottom surface 32 (facing the end wall 111) of the lower plastic 30 according to the first embodiment of the present application, Figure 10 shows the side of the bottom surface 32 (facing the end wall 111) of the lower plastic 30 according to the second embodiment of the present application, Figure 9The surface / back of the lower plastic 30 facing the end wall 111 / the surface of the electrode assembly (hereinafter referred to as the bottom surface 32) comprises a plane 322 surrounding the second assembly hole 300, and an inclined surface 321 surrounding and connecting the plane 322, the plane 322 is in contact with the surface of the end wall 111 facing the inside of the shell 200, and as the distance between the inclined surface 321 and the second assembly hole 300 increases, the distance between the inclined surface 321 and the end wall 111 increases, that is, the inclined surface 321 is not in close contact with the end wall 111, and the inclined surface 321 is inclined away from the end wall 111, so as to discharge the electrolyte between the lower plastic 30 and the shell 200 along the inclined surface 321 towards the electrode assembly, avoiding the electrolyte accumulating between the lower plastic 30 and the shell 200 to intensify the corrosion of the shell 200, and improving the safety of the secondary battery 100.

[0045] The inner ring part of the bottom surface 32 of the lower plastic 30 of the embodiment of the application is the plane 322 connected with the inclined surface 321, and the pole post 50 rivets the plane 322 part on the end wall 111, and the inclined surface 321 makes the lower plastic 30 have a roof shape, and there is a gap between the outer edge 33 of the lower plastic 30 and the side wall 112 of the shell 200 as shown in Figure 8 The gap is shown in the figure. Figure 8 In the embodiment shown, the lower plastic 30 extends beyond the inner flange 52 of the pole post 50, and in the preferred embodiment, the lower plastic 30 does not exceed the inner flange 52 of the pole post 50 in the direction from the end wall 111 to the lower plastic 30, that is, the inclined dimension of the lower plastic 30 does not exceed the maximum thickness of the inner flange 52, and the inner flange 52 itself occupies a certain longitudinal Figure 8 space in the secondary battery 100, if the lower plastic 30 exceeds the inner flange 52, the lower plastic 30 needs to occupy additional longitudinal space, that is, the space between the current collector disc welding the pole post 50 and the electrode assembly and the end wall 111 needs to be larger, the height of the secondary battery 100 becomes larger, resulting in smaller energy density of the secondary battery 100, and the lower plastic 30 of the embodiment of the application does not exceed the inner flange 52, which can ensure the smooth discharge of the electrolyte without reducing the energy density of the secondary battery 100. The included angle α between the inclined surface 321 and the end wall 111 is in the range of 1° to 30°, preferably between 5° and 15°, the included angle α is greater than 1° to ensure the inclination of the inclined surface 321, and the upper limit of the included angle α is to avoid the lower plastic 30 exceeding the inner flange 52 of the pole post 50.

[0046] The lower plastic 30 can be provided with a through-hole 35 on the inclined surface 321, extending through the lower plastic 30 along its thickness, that is, from the top surface 31 to the bottom surface 32. When the electrolyte flows along the inclined surface 321 through the through-hole 35, it can be discharged from the through-hole 35 toward the electrode assembly, thereby facilitating the circulation of the electrolyte. On the other hand, regarding the plane 322, at least a portion of the plane 322 extends beyond the inner flange 52. The distance from the end position of the plane 322 (i.e., the starting position of the inclined surface 321) to the inner flange 52 ranges from 0.1 mm to 10 mm, preferably from 0.5 mm to 3 mm. When the distance is greater than 2 mm, due to gravity, a small gap may exist between the plane 322 and the end wall 111, and electrolyte may seep into the gap. Therefore, a through-hole 35 can also be provided on the plane 322 to discharge any electrolyte that may be between the plane 322 and the end wall 111. At least one circumferential through hole 35 can be provided on the lower plastic 30. The number of through holes 35 on the same circumference is between 1 and 16. The diameter of the through hole 35 is between 0.3 mm and 5 mm, preferably between 1.0 mm and 3.0 mm. The shape of the projection of the through hole 35 is not limited to Figure 9 The circle shown may also be a rectangle, a racetrack, a parallelogram or other special shapes.

[0047] Figure 10 FIG. 1 shows one side of the bottom surface 32 (facing the end wall 111 ) of the lower plastic 30 according to the second embodiment of the present application. Figure 12 Shown along Figure 11 In the second embodiment, the lower plastic 30 includes a weak portion 39 disposed between the plane 322 and the inclined surface 321. A plurality of through-holes 35 are provided at the weak portion 39. The thickness of the lower plastic 30 at the through-holes 35 is zero to reduce the strength of the weak portion 39, allowing the lower plastic 30 to bend more easily to form the inclined surface 321 at an angle β with the plane 322. The angle β is equal to the angle α between the inclined surface 321 and the end wall 111. The diameter of the through-holes 35 formed at the weak portion 39 can be smaller than that at the inclined surface 321 to avoid excessive weakness of the overall structure of the lower plastic 30 due to a large hole in the inner ring. In other embodiments, the through hole 35 may not be provided in the weak portion 39 , but the thickness of a portion or the entire circle of the weak portion 39 may be reduced so that at least a portion of the thickness is less than the thickness of the lower plastic 30 at the plane 322 or at the inclined surface 321 . For example, at least a portion of the thickness is 0.1 to 0.9 times the thickness of the lower plastic 30 at the plane 322 or at the inclined surface 321 .

[0048] Figure 13 FIG. 1 shows one side of the bottom surface 32 (facing the end wall 111 ) of the lower plastic 30 according to the third embodiment of the present application. Figure 14 Shown along Figure 13DD line. In the first and second embodiments, the lower plastic 30 includes a straight portion corresponding to the plane 322 and an inclined portion corresponding to the inclined surface 321. The inclined portion is inclined relative to the straight portion in a direction away from the end wall 111. That is, the surface of the inclined portion facing the electrode assembly is also inclined relative to the straight portion. The thickness between the top surface 31 and the bottom surface 32 of the lower plastic 30 can be consistent, that is, the lower plastic 30 has a uniform wall thickness. The third embodiment shows a lower plastic 30 with unequal wall thickness. The lower plastic 30 is not the first and second embodiments in which the inclined portion corresponding to the inclined surface 321 is inclined relative to the straight portion as a whole. Instead, its top surface 31 is still a straight surface, and the inclined inclined surface 321 is formed in the bottom surface 32 by gradually reducing the thickness of the lower plastic 30 radially outward. The thickness t1 of the lower plastic 30 at the plane 322 ranges from 0.4 mm to 2.0 mm, preferably from 0.6 mm to 1.2 mm, and the thickness t2 of the lower plastic 30 at the outer edge 33 ranges from 0.1 mm to 1.5 mm, preferably from 0.2 mm to 0.7 mm, and t2 is smaller than t1.

[0049] Figure 15 FIG. 1 shows one side of the bottom surface 32 (facing the end wall 111 ) of the lower plastic 30 according to the fourth embodiment of the present application. Figure 16 Shown along Figure 15 The fourth embodiment is different from the first to third embodiments in that the lower plastic 30 of the fourth embodiment does not have a through hole 35 formed therein.

[0050] During the cycle of the secondary battery 100, gas may be generated and expanded. The expansion of the electrode sheets causes the electrode assembly to expand first in the circumferential direction, and then the outer electrode sheets bulge toward the ends of the secondary battery 100. As a result, the electrode sheets will push / press the current collecting plate and the lower plastic 30 upward, which may cause the lower plastic 30 to fit against the end wall 111. After the lower plastic 30 is pressed until it is no longer tilted, its size may be larger than the diameter of the end wall 111, causing the outer edge 33 of the lower plastic 30 to contact the side wall 112, resulting in local concave deformation of the lower plastic 30 and accumulation of electrolyte, as in the prior art. In the first to fourth embodiments, a reinforcing rib protruding toward the end wall 111 can be provided on the inclined surface 321 of the lower plastic 30 to provide support for the inclined surface 321 of the lower plastic 30, thereby preventing the inclined surface 321 from being pushed against the end wall 111 by the bulging electrode sheets and maintaining the inclination of the inclined surface 321.

[0051] In addition, the formation of the lower plastic 30 in the first to fourth embodiments of the present application can be achieved in one step by injection molding.

[0052] The embodiment of the present application provides a roof-shaped lower plastic 30, a bottom surface 32 of the lower plastic 30 is not an entire plane, but includes a plane 322 and an inclined surface 321, the plane 322 and the inclined surface 321 have a certain angle, the inclined surface 321 is not attached to an end wall 111, and the inclined surface 321 is inclined to a direction away from the end wall 111, so that electrolyte between the lower plastic 30 and a shell 200 is discharged along the inclined surface 321 to a direction of an electrode assembly, electrolyte is prevented from gathering between the lower plastic 30 and the shell 200 to cause concentrated corrosion to the shell 200, and the safety of the secondary battery 100 is improved. The lower plastic 30 can be equal-wall-thickness, a part where the inclined surface 321 is located is inclined to the direction away from the end wall 111 as a whole, the lower plastic 30 can also be variable-wall-thickness, the inclined surface 321 is formed through transition between high thickness and low thickness, electrolyte is facilitated to flow out, and a through hole 35 can also be arranged on the lower plastic 30, which is more beneficial to the flow of electrolyte.

[0053] The embodiment of the present application also provides a battery pack 1002, which comprises the secondary battery 100 described in any one of the above embodiments, and the battery pack 1002 can have the beneficial effects described above with respect to the secondary battery 100.

[0054] The embodiment of the present application also provides an electronic device 1000, which comprises the battery pack 1002 described above, and the electronic device 1000 can have the beneficial effects described above with respect to the secondary battery 100 and / or the battery pack 1002.

[0055] The above only describes preferred embodiments of the present application and is not used to limit the present application, and the present application can have various changes and variations for those skilled in the art. 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 secondary battery includes: a case including an end wall and a side wall surrounding the end wall, the end wall having a first fitting hole; a lower plastic having a second fitting hole corresponding to the first fitting hole, a surface of the lower plastic facing the end wall including a flat surface surrounding the second fitting hole and a bevel surface surrounding and connecting the flat surface, the flat surface being in contact with a surface of the end wall facing an inside of the case, a distance between the bevel surface and the end wall increasing as a distance between the bevel surface and the second fitting hole increases; a pole including a columnar portion passing through the first fitting hole and the second fitting hole and an inner flange connected to an end of the columnar portion inside the case and clamping the lower plastic together with the end wall.

2. The secondary battery according to claim 1, characterized by a gap is present between an outer edge of the lower plastic and the side wall.

3. The secondary battery according to claim 1, characterized by the lower plastic does not exceed the inner flange of the pole in a direction from the end wall to the lower plastic, an angle between the bevel surface and the end wall is in a range of 1° to 30°.

4. The secondary battery according to claim 1, wherein the lower plastic is provided with a through hole penetrating itself in a thickness direction of the lower plastic at the bevel surface.

5. The secondary battery according to claim 4, characterized by a distance between the inner flange and the bevel surface is greater than 2 mm, and the lower plastic is also provided with the through hole at the flat surface.

6. The secondary battery according to claim 1, characterized by the bevel surface of the lower plastic is provided with a reinforcing rib protruding toward the end wall.

7. The secondary battery according to claim 1, wherein the lower plastic includes a flat portion corresponding to the flat surface and an inclined portion corresponding to the bevel surface, the inclined portion as a whole being inclined relative to the flat portion in a direction away from the end wall, or a surface of the lower plastic facing the inside of the case is a flat surface.

8. The secondary battery according to claim 1, wherein the lower plastic includes a weak portion provided at a position between the flat surface and the bevel surface, at least a portion of the weak portion having a thickness smaller than a thickness of the lower plastic at the flat surface or at the bevel surface.

9. A battery pack characterized by comprising: The secondary battery according to any one of claims 1 to 8.

10. An electronic device, comprising: The battery pack according to claim 9.

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