Secondary battery and battery pack

Abstract

The utility model provides a secondary battery and a battery pack. The secondary battery comprises a shell, an electrode assembly, a pole and a sealing element, the shell comprises an end wall and a side wall surrounding the end wall, and the end wall is provided with a pole hole; the electrode assembly is arranged in the shell; the pole penetrates through the end wall and is electrically connected with the electrode assembly; the sealing element is positioned between the pole and the end wall; the range of the compression ratio w of the sealing element is 20% < = w < = 50%, and the technical problem that the sealing performance of an existing sealing element between the pole and the shell is reduced under the influence of temperature rise can be solved.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and particularly relates to a secondary battery and a battery pack. Background Art

[0002] At present, due to the advantages of mature production process, high production yield, low processing cost, good safety performance and heat dissipation performance of cylinders, they are widely used in all walks of life.

[0003] Between the pole column and the shell of the existing cylindrical battery, insulation isolation is usually carried out by setting an insulating part, and sealing is carried out by a sealing part. When the temperature of the cylindrical battery rises, the insulating part has a phenomenon of thermal shrinkage, which increases the gap between the pole column and the shell, and the sealing ring will rebound, resulting in a reduction in the sealing performance of the sealing part. In severe cases, even liquid leakage may occur. Summary of the Utility Model

[0004] In view of the above disadvantages of the prior art, the utility model provides a secondary battery and a battery pack to improve the technical problem that the sealing performance of the sealing part between the pole column and the shell in the prior art is reduced under the influence of temperature rise.

[0005] To achieve the above object and other related objects, the utility model provides a secondary battery, which includes: a shell, an electrode assembly, a pole column and a sealing part; the shell includes an end wall and a side wall surrounding the end wall, and a pole column hole is provided on the end wall; the electrode assembly is arranged inside the shell; the pole column penetrates the end wall and is electrically connected to the electrode assembly; the sealing part is located between the pole column and the end wall; the compression ratio w of the sealing part ranges from 20% ≤ w ≤ 50%.

[0006] In the above technical solution, the compression ratio of the sealing part is the ratio of the difference between the initial thickness of the sealing part and the thickness of the sealing part after assembly compression to the initial thickness of the sealing part. Setting the compression ratio w of the sealing part in the range of 20% ≤ w ≤ 50% can not only make the sealing part have a better sealing effect at normal temperature, but also achieve the effect that when the temperature of the secondary battery rises, even if the sealing part rebounds, it can still maintain a high sealing performance, thereby improving the technical problem of liquid leakage.

[0007] In an example of the secondary battery of the utility model, the pole column includes a columnar part, an outer flange and an inner flange. The columnar part penetrates the pole column hole. The outer flange is located outside the shell and extends from the columnar part to the outer peripheral edge of the end wall. The inner flange is located inside the shell and extends from the columnar part to the outer peripheral edge of the end wall. The sealing part is located between the outer flange and the end wall. Along the radial direction of the pole column, the ratio of the width a of the part of the sealing part clamped by the outer flange and the end wall to the difference between the radius r1 of the outer flange and the radius r2 of the pole column hole is i, where 50% ≤ i ≤ 90%.

[0008] In the above technical solution, since the sealing member is in direct contact with the outer flange and the end wall at the clamping portion between the outer flange and the end wall and can be directly pressed by the outer flange and the end wall, it is the effective sealing portion of the sealing ring. The portion of the difference between the radius r1 of the outer flange and the radius r2 of the pole hole is the sealable portion that can be used for sealing between the outer flange and the end wall. Setting the ratio i of the length of the effective sealing portion to the length of the sealable portion at 50% ≤ i ≤ 90% can provide an installation space for the insulating member while enabling the sealing member to have a relatively large effective sealing length, which is beneficial to improving the sealing performance of the sealing member.

[0009] In an example of the secondary battery of the present utility model, the ratio of the difference between the radius r1 of the outer flange and the radius r3 of the columnar portion to the radius r1 of the outer flange is b, where 30% ≤ b ≤ 50%.

[0010] In the above technical solution, the portion of the difference between the radius r1 of the outer flange and the radius r2 of the columnar portion is the cantilever portion of the outer flange relative to the columnar portion. Setting the ratio b in the range of 30% ≤ b ≤ 50% can achieve a shorter size of the cantilever on the premise of providing a relatively large sealing space for the sealing ring. This setting can improve the strength of the cantilever, prevent the edge of the outer flange from warping, and can provide a relatively constant pressing force to the sealing member, further improving the sealing performance of the sealing member.

[0011] In an example of the secondary battery of the present utility model, the secondary battery further includes a lower plastic. The lower plastic includes a first insulator located between the pole hole and the columnar portion. Along the radial direction of the pole, the thickness c of the first insulator ranges from 0.4 mm ≤ c ≤ 0.9 mm.

[0012] In the above technical solution, the lower plastic is used to isolate the end wall and the electrode assembly, and to isolate the end wall and the pole. The first insulator is mainly used to isolate the end wall and the pole. Setting the thickness of the first insulator to be greater than or equal to 0.4 mm can enable the first insulator to have high voltage resistance performance. At the same time, limiting the thickness of the first insulator to be less than or equal to 0.9 mm increases the effective sealing length of the sealing member, which is beneficial to improving the sealing performance of the sealing member.

[0013] In an example of the secondary battery of the present utility model, along the direction in which the pole penetrates, the first insulator is lower than the side of the pole hole close to the outer flange and forms a first receiving groove for receiving the sealing member. The depth e of the first receiving groove is such that 0.05 mm ≤ e ≤ 0.2 mm.

[0014] In the above technical solution, when the compression ratio of the seal is increased, the corresponding deformation of the seal will also increase. The first receiving groove can accommodate a larger deformation of the seal. When the seal rebounds due to high temperature, the seal can still have a relatively high compression ratio. The depth of the first receiving groove is greater than or equal to 0.05 mm, which can provide a certain accommodation space for the seal. The limitation that the depth is less than or equal to 0.2 mm can achieve a better isolation and insulation effect of the first insulator on the end wall and the pole column, and enable the first insulator to have a relatively high strength.

[0015] In an example of the secondary battery of the present utility model, along the direction of penetration of the pole column, the inner edge and the outer edge of the first insulator on the side close to the outer flange have different heights.

[0016] In the above technical solution, by setting the bottom surface of the first receiving groove as an inclined surface, it can be achieved that while not reducing the accommodation space of the first receiving groove, the first insulator can still have a relatively high height, which can prevent the risk of short circuit between the columnar part and the end wall when the seal is unevenly filled, so as to obtain a better isolation and insulation effect. In addition, this setting makes the seal also have a relatively high height in the direction of penetration of the pole column, which is beneficial to improving the sealing effect of the seal.

[0017] In an example of the secondary battery of the present utility model, along the direction of penetration of the pole column, the distance from the inner edge to the outer flange is greater than the distance from the outer edge to the outer flange.

[0018] In the above technical solution, since the wall thickness of the end wall is relatively thin, by setting the distance from the outer edge of the first insulator to the outer flange to be relatively short, a relatively large contact area between the first insulator and the pole column hole can be achieved, which is beneficial to the stability of pressing between the end wall and the first insulator.

[0019] In an example of the secondary battery of the present utility model, the secondary battery further includes an upper plastic. The upper plastic includes a second insulator clamped between the outer flange and the end wall. A chamfer is provided on the side of the second insulator close to the seal to form a second receiving groove for accommodating the seal. Along the radial direction of the pole column, the length of the chamfer is g, and along the penetration direction of the pole column, the length of the chamfer is p, where p≥g and 0.2 mm≤g≤0.6 mm.

[0020] In the above technical solution, the provision of the second receiving groove can increase the filling space for the seal. Additionally, setting the second receiving groove in the form of a chamfer can prevent the risk of short - circuit between the outer flange and the end wall when the seal is unevenly filled. p≥g means that the length of the chamfer in the radial direction is less than or equal to its length in the axial direction. This setting enables, when pressure is applied to the second insulator by the outer flange, the effect that the second insulator is not easily disengaged. On the one hand, it improves the insulation effect between the outer flange and the end wall. On the other hand, the improved stability of the upper plastic is also beneficial to the sealing effect of the seal. g≥0.2mm, that is, the maximum depth of the second receiving groove is greater than or equal to 0.2mm, which can provide a certain accommodation space for the seal. g≤0.6mm, that is, the maximum depth of the second receiving groove is less than or equal to 0.6mm. This limitation can achieve the effect that the second insulator is not easily disengaged, providing a good isolation and insulation effect between the end wall and the outer flange, and enabling the second insulator to have relatively high strength.

[0021] In an example of the secondary battery of the present utility model, along the direction in which the pole post penetrates, the inner edge radius of the side of the second insulator provided with the chamfer is r4. Along the radial direction of the pole post, r1 - r4≥0.3mm.

[0022] In the above technical solution, first, the inner edge of the side of the second insulator provided with the chamfer is located radially inside the outer edge of the outer flange, and it is further defined that r1 - r4≥0.3mm. That is, along the radial direction of the pole post, at least 0.3mm of the width of the second insulator is directly clamped by the outer flange and the end wall. This setting improves the stability of the upper plastic that can be clamped by the outer flange and the end wall. On the one hand, it improves the insulation effect between the outer flange and the end wall. On the other hand, the improved stability of the upper plastic is also beneficial to the sealing effect of the seal.

[0023] In an example of the secondary battery of the present utility model, along the direction in which the pole post penetrates, the thickness of the second insulator is h, where 0.5mm≤h≤1mm.

[0024] In the above technical solution, the setting of h≤1mm for the thickness of the second insulator reduces the gap between the outer flange and the end wall, providing a necessary condition for improving the compression ratio of the seal. The setting of h≥0.5mm can ensure that the insulation effect of the second insulator is not affected.

[0025] In an example of the secondary battery of the present utility model, the upper plastic further includes a third insulator integrally formed with the second insulator. The third insulator is connected to the outer periphery of the second insulator and is disposed around the outer periphery of the outer flange. Along the radial direction of the pole post, the width of the third insulator is j, where j≥0.5mm.

[0026] In the above technical solution, the width of the third insulator is set to j≥0.5mm to achieve sufficient creepage distance.

[0027] The present utility model further provides a battery pack, which includes the secondary battery of any one of the above.

[0028] For the secondary battery of the present utility model, by setting the compression ratio w of the seal within the range of 20% ≤ w ≤ 50%, it can not only make the seal have a better sealing effect at normal temperature, but also achieve the effect that when the temperature of the secondary battery rises, even if the seal rebounds, it can still maintain a high sealing performance, thereby improving the technical problem of liquid leakage. Description of the Drawings

[0029] In order to more clearly illustrate the technical solutions in the embodiments of the present utility model or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are only some embodiments of the present utility model. For those of ordinary skill in the art, without creative efforts, other embodiments can be obtained based on these drawings.

[0030] Figure 1 It is a schematic structural diagram of an example of the secondary battery of the present utility model;

[0031] Figure 2 It is a schematic structural diagram of the electrode assembly of an example of the secondary battery of the present utility model;

[0032] Figure 3 It is Figure 1 a partial enlarged view of the A position in an example of the secondary battery of the present utility model;

[0033] Figure 4 It is Figure 3 a partial enlarged view of the B position;

[0034] Figure 5 It is Figure 1 a partial enlarged view of the A position in another example of the secondary battery of the present utility model;

[0035] Figure 6 It is Figure 5 a partial enlarged view of the D position;

[0036] Figure 7 It is Figure 5 a partial enlarged view of the C position;

[0037] Figure 8 It is a schematic diagram of an example of the battery pack of the present utility model;

[0038] Figure 9 It is a schematic diagram of an example of the electronic device of the present utility model.

[0039] Description of Component Labels

[0040] 1. Electronic device; 10. Battery pack; 11. Working part; 101. Box body; 102. Box cover; 100. Secondary battery; 110. Housing; 111. End wall; 1111. Pole hole; 112. Side wall; 113. Opening; 120. Electrode assembly; 121. Positive electrode plate; 1211. Positive current collector; 1212. First coating area; 1213. First uncoated area; 122. Separator; 123. Negative electrode plate; 1231. Negative current collector; 1232. Second coating area; 1233. Second uncoated area; 124. Negative electrode tab; 125. Positive electrode tab; 130. Cover plate; 140. Pole; 141. Inner flange; 142. Columnar part; 143. Outer flange; 150. Seal; 160. Lower plastic; 161. First insulator; 1611. First receiving groove; 170. Upper plastic; 171. Second insulator; 1711. Second receiving groove; 172. Third insulator. Detailed implementation manners

[0041] The following uses specific specific examples to illustrate the implementation manners of the present utility model. Those skilled in the art can easily understand other advantages and effects of the present utility model from the content disclosed in this specification. The present utility model can also be implemented or applied through other different specific implementation manners. Various details in this specification can also be modified or changed based on different viewpoints and applications without departing from the spirit of the present utility model. It should be noted that, without conflict, the following embodiments and the features in the embodiments can be combined with each other. It should also be understood that the terms used in the embodiments of the present utility model are for describing specific specific implementation manners, rather than for limiting the protection scope of the present utility model. The test methods without specific conditions noted in the following embodiments are usually in accordance with conventional conditions or in accordance with the conditions recommended by each manufacturer.

[0042] When the embodiments give a numerical range, it should be understood that unless otherwise stated in the present utility model, any value between the two endpoints of each numerical range and any value between the two endpoints can be selected. Unless otherwise defined, all technical and scientific terms used in the present utility model, based on the understanding of those skilled in the art of the prior art and the description of the present utility model, can also use any methods, devices, and materials of the prior art similar or equivalent to the methods, devices, and materials in the embodiments of the present utility model to implement the present utility model.

[0043] It should be noted that the terms such as "upper", "lower", "left", "right", "middle", and "one" cited in this specification are only for the convenience of clear narration, rather than for limiting the scope of implementation of the present utility model. The change or adjustment of their relative relationships, without substantial change in the technical content, should also be regarded as the scope of implementation of the present utility model.

[0044] The secondary battery includes an electrode assembly, which is a component in the secondary battery where electrochemical reactions occur and can include one or more electrode assemblies.

[0045] The secondary battery further includes a housing, a cover plate, and a terminal post. The housing includes an end wall and a side wall surrounding the end wall. One end of the side wall has an opening. The electrode assembly can be assembled into the housing through the opening of the housing. The cover plate is used to cover the opening of the housing to achieve sealing. The terminal post passes through the end wall and is electrically connected to the electrode assembly to export the electrical energy generated by the electrode assembly.

[0046] In order to reduce the risk of short circuit, it is necessary to insulate and isolate the terminal post and the end wall, and isolate the electrode assembly and the end wall. In order to reduce the risk of liquid leakage between the terminal post and the end wall, the method of setting an insulating member and a sealing member between the terminal post and the end wall is usually adopted.

[0047] The inventor found that in the existing secondary battery, when the temperature rises, the insulating member has a phenomenon of thermal shrinkage, which increases the gap between the terminal post and the housing. The sealing ring will rebound, resulting in a decrease in the sealing performance of the sealing member. In severe cases, liquid leakage may even occur.

[0048] In view of this, the present utility model provides a technical solution, in which the compression ratio w of the sealing member is set within the range of 20% ≤ w ≤ 50% to improve the technical problem that the sealing performance of the sealing member between the existing terminal post and the housing decreases under the influence of temperature rise.

[0049] Please refer to Figures 1 to 9 , the present utility model provides a secondary battery 100, which includes a housing 110, an electrode assembly 120, a terminal post 140, and a sealing member 150.

[0050] Please refer to Figure 1, the housing 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111. As long as a stable sealing and electrical connection relationship can be formed, the connection between the end wall 111 and the side wall 112 can be achieved in various ways. For example, it can be integrally stamped, integrally cast, or separately welded, etc. The surrounding of the side wall 112 is not limited. It can be cylindrical or prismatic, or it can surround along any other closed-loop contour that can match the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, and the side wall 112 is cylindrically surrounded around the outer edge of the end wall 111, and a circular opening 113 is formed at one end of the side wall 112 facing away from the end wall 111. An accommodation cavity is formed inside the housing 110 surrounded by the end wall 111 and the side wall 112 for accommodating the electrode assembly 120, the electrolyte, and other necessary battery components. Specifically, the diameter of the housing 110 can be determined according to the specific size of the electrode assembly 120, such as 18mm, 21mm, 46mm, etc. The material of the housing 110 can be various, such as copper, iron, aluminum, steel, aluminum alloy, etc. In order to prevent the housing 110 from rusting during long-term use, an anti-rust material such as metallic nickel can also be plated on the surface of the housing 110.

[0051] Please refer to Figures 1 to 2 , the electrode assembly 120 is disposed inside the housing 110, and the electrode assembly 120 is a component that undergoes an electrochemical reaction in the secondary battery 100. One or more electrode assemblies 120 can be included in the housing 110. The electrode assembly 120 includes electrode plates and a separator 122, and the electrode plates and the separator 122 are wound to form a wound structure. Specifically, in this embodiment, the electrode assembly 120 includes a positive electrode plate 121, a separator 122, and a negative electrode plate 123 wound around the axis of the housing 110.

[0052] Please refer to Figures 1 to 2 , the positive electrode plate 121 includes a positive current collector 1211 and a positive active material layer coated on the positive current collector 1211. A first coated area 1212 coated with the positive active material layer and a first uncoated area 1213 not coated with the positive active material layer are formed on the positive current collector 1211. The first coated area 1212 and the first uncoated area 1213 are arranged along the axis of the housing 110. The first uncoated area 1213 extends to the outside of the separator 122 at one end in the height direction of the secondary battery 100 and bends towards the axis of the housing 110 to form a stacked positive electrode tab 125.

[0053] Please refer to Figures 1 to 2, the negative electrode tab 123 includes a negative electrode current collector 1231 and a negative electrode active material layer coated on the negative electrode current collector 1231. 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 along the axial direction of the housing 110. The second uncoated area 1233 extends to the other end in the height direction of the secondary battery 100 outside the separator 122 and bends towards the axis of the housing 110 to form a stacked negative electrode tab 124.

[0054] Please refer to Figures 1 to 2 , the separator 122 is disposed between the positive electrode tab 121 and the negative electrode tab 123 to isolate the positive electrode active material layer and the negative electrode active material layer. Taking the lithium-ion secondary battery 100 as an example, the material of the positive electrode current collector 1211 can be aluminum, and the positive electrode active material layer includes a positive electrode active material, which can be lithium cobaltate, lithium iron phosphate, ternary lithium, lithium manganate, etc. The material of the negative electrode current collector 1231 can be copper, and the negative electrode active material layer includes a negative electrode active material, which can be carbon or silicon, etc. The base material of the separator 122 can be polypropylene (PP for short) or polyethylene (PE for short), etc. To protect and insulate the battery cell, an insulating film can also be coated outside the battery cell, and the insulating film can be synthesized from PP, PE, polyethylene terephthalate (PET for short), polyvinyl chloride (PVC for short), or other polymer materials.

[0055] Please refer to Figure 1 and Figure 2 , further, in the present utility model, the positive electrode tab 125 faces the end wall 111 or the opening 113, then the negative electrode tab 124 faces the other end of the housing 110. In this embodiment, the positive electrode tab 125 faces the end wall 111 and is electrically connected to the pole column 140 to make the pole column 140 positively charged, and the negative electrode tab 124 faces the opening 113, and the housing 110 is electrically connected to the negative electrode tab 124, thus being negatively charged. However, in other embodiments, the negative electrode tab 124 can also be connected to the pole column 140, and the positive electrode tab 125 can be connected to the housing 110.

[0056] Please refer to Figure 1 , the cover plate 130 is sealed and installed on the opening 113; the outer edge shape of the cover plate 130 corresponds to the shape of the opening 113 and is connected to the side wall 112 to seal the opening 113. The installation method of the cover plate 130 includes but is not limited to mechanical sealing or welding sealing. In this embodiment, the cover plate 130 is sealed and plugged on the opening 113 by mechanical sealing.

[0057] Please refer to Figures 3 to 5 , the terminal post 140 is fixed to the end wall 111 and electrically connected to the electrode assembly 120. Specifically, the end wall 111 is provided with a terminal post hole 1111, and the terminal post 140 is installed through the terminal post hole 1111 and insulated from the end wall 111. One end of the terminal post 140 facing the electrode assembly 120 passes through the end wall 111 and is directly electrically connected to the positive electrode tab 125 or indirectly connected through an intermediate connection. The structural form of the terminal post 140 can be any suitable form that can pass through the end wall 111 and be electrically connected to the positive electrode tab 125 of the electrode assembly 120. For example, the cross-section can be circular, square, prismatic or an irregular profile that can achieve stable electrical conduction. The shape of the terminal post hole 1111 corresponds to the shape of the terminal post 140. In this embodiment, the cross-section of the terminal post 140 is circular.

[0058] Please refer to Figures 3 to 5 , the terminal post 140 includes a columnar portion 142, an outer flange 143 and an inner flange 141. The columnar portion 142 passes through the terminal post hole 1111. The cross-section of the columnar portion 142 can be circular, square, prismatic or other irregular profiles that can achieve stable electrical conduction. Considering the better sealing and mating effects, preferably, the columnar portion 142 is adapted to the terminal post hole 1111, that is, the shape of the terminal post hole 1111 corresponds to the shape of the columnar portion 142. In this embodiment, the cross-section of the columnar portion 142 is circular. The circular design facilitates processing, assembly and sealing.

[0059] Please refer to Figures 3 to 5 , the outer flange 143 is located outside the housing 110 and extends from the columnar portion 142 to the outer peripheral edge of the end wall 111. The outer shape cross-section of the outer flange 143 can be circular, square, prismatic or other irregular profiles that can achieve stable electrical conduction, and no limitation is made thereto; the inner flange 141 is located inside the housing 110 and extends from the columnar portion 142 to the outer peripheral edge of the end wall 111. Specifically, the inner flange 141 connects one end of the columnar portion 142 located inside the housing 110 and extends along the side of the end wall 111 facing the inside of the housing 110 towards the outer edge of the end wall 111; the outer shape cross-section of the inner flange 141 can be circular, square, prismatic or other irregular profiles that can achieve stable electrical conduction, and no limitation is made thereto.

[0060] Please refer to Figures 3 to 6, the seal 150 is located between the terminal post 140 and the end wall 111. The position of the seal 150 between the terminal post 140 and the end wall 111 is not limited. It can be only arranged between the outer flange 143 and the end wall 111, only arranged between the columnar part 142 and the terminal post hole 1111, only arranged between the inner flange 141 and the end wall 111, or can also be arranged in a combination of two or three of the above three positions. As long as the seal between the terminal post 140 and the end wall 111 can be achieved by an elastic member with a certain compression ratio, the phenomenon of liquid leakage between the terminal post 140 and the end wall 111 can be avoided. The material of the seal 150 is any one of soluble polytetrafluoroethylene (Perfluoroalkoxy, abbreviated as PFA), polybutylene terephthalate (Polybutylene Terephthalate, abbreviated as PBT), liquid crystal polymer (Liquid Crystal Polymer, abbreviated as LCP), PP, polyphenylene sulfide (Polyphenylene Sulfide, abbreviated as PPS), and polycarbonate (Polycarbonate, abbreviated as PC), and there is no limitation on this.

[0061] Considering that when the temperature of the secondary battery 100 rises, the insulating part has the phenomenon of thermal shrinkage, which increases the gap between the terminal post 140 and the housing 110, and the sealing ring will rebound, resulting in a reduction in the sealing performance of the seal 150. The range of the compression ratio w of the seal 150 is set as: 20% ≤ w ≤ 50%. For example, it can be 20%, 25%, 30%, 35%, 40%, 45% or 50%, etc. The compression ratio of the seal 150 is the ratio of the difference between the initial thickness of the seal 150 and the thickness of the seal 150 after assembly compression to the initial thickness of the seal 150. It should be noted that the seal 150 is in a compressed state after assembly. At this time, the thickness of the seal 150 can be obtained by measuring after performing a CT or making a cross-section on the secondary battery 100. The initial thickness of the seal 150 can be measured before installation, or can also be measured after removing the seal 150 in the secondary battery 100 and allowing it to rebound. This setting can not only make the seal 150 have a better sealing effect at normal temperature, but also achieve the effect that when the temperature of the secondary battery 100 rises, even if the seal 150 rebounds, it can still maintain a high sealing performance, thereby improving the technical problem of liquid leakage.

[0062] Please refer to Figures 3 to 5, in an example of the secondary battery 100 of the present utility model, along the radial direction of the terminal post 140, the ratio of the width a of the portion of the seal 150 clamped by the outer flange 143 and the end wall 111 to the difference between the radius r1 of the outer flange 143 and the radius r2 of the terminal post hole 1111 is i, where 50% ≤ i ≤ 90%. For example, it can be 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85% or 90%, etc. Since the portion of the seal 150 clamped by the outer flange 143 and the end wall 111 is in direct contact with the outer flange 143 and the end wall 111 and can be directly pressed by the outer flange 143 and the end wall 111, it is the effective sealing portion of the sealing ring. The portion of the difference between the radius r1 of the outer flange 143 and the radius r2 of the terminal post hole 1111 is the sealable portion that can be used for sealing between the outer flange 143 and the end wall 111. Setting the ratio i of the length of the effective sealing portion to the length of the sealable portion at 50% ≤ i ≤ 90% can achieve providing an installation space for the insulating member while enabling the seal 150 to have a relatively large effective sealing length, which is beneficial to improving the sealing performance of the seal 150.

[0063] Please refer to Figure 4 , in an example of the secondary battery 100 of the present utility model, the ratio of the difference between the radius r1 of the outer flange 143 and the radius r3 of the columnar portion 142 to the radius r1 of the outer flange 143 is b, where 30% ≤ b ≤ 50%. For example, it can be: 30%, 33%, 35%, 36%, 40%, 45%, 47% or 50%. The portion of the difference between the radius r1 of the outer flange 143 and the radius r2r3 of the columnar portion 142 is the cantilever portion of the outer flange 143 relative to the columnar portion 142. Setting the ratio b in the range of 30% ≤ b ≤ 50% can achieve having a relatively short size of the cantilever on the premise of providing a relatively large sealing space for the sealing ring. This setting can improve the strength of the cantilever, prevent the edge of the outer flange 143 from warping easily, and can provide a relatively constant pressing force to the seal 150, further improving the sealing performance of the seal 150.

[0064] Please refer to Figures 3 to 6, in an example of the secondary battery 100 of the present utility model, the secondary battery 100 further includes a lower plastic 160, and the lower plastic 160 surrounds the columnar portion 142; the material of the lower plastic 160 is any one of PP, PPS, PC, PFA, PBT, and LCP, and there is no limitation thereto. The lower plastic 160 includes a first insulator 161 located between the pole hole 1111 and the columnar portion 142. Along the radial direction of the pole 140, the thickness c of the first insulator 161 ranges from 0.4 mm ≤ c ≤ 0.9 mm. For example, it can be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm, etc. The lower plastic 160 is used to isolate the end wall 111 and the electrode assembly 120, and to isolate the end wall 111 and the pole 140. Among them, the first insulator 161 is mainly used to isolate the end wall 111 and the pole 140. Setting the thickness of the first insulator 161 to be greater than or equal to 0.4 mm can enable the first insulator 161 to have higher voltage withstand performance. At the same time, limiting the thickness of the first insulator 161 to be less than or equal to 0.9 mm increases the effective sealing length of the seal 150, which is beneficial to improving the sealing performance of the seal 150.

[0065] Please refer to Figures 3 to 6 , considering that when the compression ratio of the seal 150 increases, the corresponding deformation amount of the seal 150 will also increase. In an example of the secondary battery 100 of the present utility model, along the direction in which the pole 140 penetrates, the first insulator 161 is lower than the side of the pole hole 1111 close to the outer flange 143, and a first receiving groove 1611 for receiving the seal 150 is formed. The setting of the first receiving groove 1611 can accommodate a larger deformation amount of the seal 150. When the high temperature causes the seal 150 to rebound, the seal 150 can still have a high compression ratio. Further, the depth of the first receiving groove 1611 is e, where 0.05 mm ≤ e ≤ 0.2 mm. For example, it can be 0.05 mm, 0.07 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.17 mm, or 0.2 mm. The depth of the first receiving groove 1611 being greater than or equal to 0.05 mm can provide a certain accommodation space for the seal 150. The limitation of the depth being less than or equal to 0.2 mm can achieve a good isolation and insulation effect of the first insulator 161 on the end wall 111 and the pole 140, and enable the first insulator 161 to have higher strength.

[0066] Please refer to Figures 5 to 6, Considering that there may be a gap between the end wall 111 and the columnar part 142 when the seal 150 is unevenly filled, and there is still a risk of short circuit. In an example of the secondary battery 100 of the present utility model, along the direction in which the pole 140 penetrates, the inner edge and the outer edge of the first insulator 161 near the outer flange 143 have different heights. The bottom surface of the first receiving groove 1611 is set as an inclined surface. Without reducing the receiving space of the first receiving groove 1611, the first insulator 161 can still have a relatively high height to obtain a better isolation and insulation effect. The side of the bottom surface close to the pole hole 1111 can be lower than the side close to the columnar part 142, or can be higher than the side close to the columnar part 142. Both of the above two methods can make the seal 150 also have a relatively high height in the direction in which the pole 140 penetrates, which is beneficial to improving the sealing effect of the seal 150.

[0067] Considering that the wall thickness of the end wall 111 is relatively thin, in an example of the secondary battery 100 of the present utility model, please refer to Figure 5 and Figure 7 , along the direction in which the pole 140 penetrates, the distance from the inner edge to the outer flange 143 is greater than the distance from the outer edge to the outer flange 143. This setting can achieve a relatively large contact area between the first insulator 161 and the pole hole 1111, which is beneficial to the stability of the pressing between the end wall 111 and the first insulator 161.

[0068] Please refer to Figure 5 and Figure 7 , in an example of the secondary battery 100 of the present utility model, the secondary battery 100 further includes an upper plastic 170. The upper plastic 170 includes a second insulator 171 clamped between the outer flange 143 and the end wall 111. Along the radial direction of the pole 140, considering the risk of short circuit between the outer flange 143 and the end wall 111 when the seal 150 is unevenly filled, in an example of the secondary battery 100 of the present utility model, a chamfer is provided on the side of the second insulator 171 close to the seal 150 to form a second receiving groove 1711 for receiving the seal 150, so as to increase the filling space of the seal 150. In addition, setting the second receiving groove 1711 in the form of a chamfer can prevent the risk of short circuit between the outer flange 143 and the end wall 111 when the seal 150 is unevenly filled. The chamfer can be provided on the edge of the second insulator 171 close to the outer flange 143, or can be provided on the edge close to the end wall 111. In this embodiment, the chamfer is provided on the edge of the second insulator 171 close to the end wall 111, so that the width of the side of the second insulator 171 close to the outer flange 143 is greater than the width of the side close to the end wall 111, which can achieve a larger contact surface between the second insulator 171 and the outer flange 143 to improve the pressing force of the outer flange 143 on the second insulator 171.

[0069] Further, along the radial direction of the terminal post 140, the length of the chamfer is g, and along the penetrating direction of the terminal post 140, the length of the chamfer is p, where p ≥ g. The condition p ≥ g means that the length of the chamfer in the radial direction is less than or equal to its length in the axial direction. This setting enables the upper plastic 170 to be not easily disengaged when the outer flange 143 applies pressure to the second insulator 171. Preferably, 0.2 mm ≤ g ≤ 0.6 mm. The value of g can be, for example: 0.2 mm, 0.25 mm, 0.3 mm, 0.35 mm, 0.4 mm, 0.45 mm, 0.5 mm, 0.55 mm or 0.6 mm, etc. g ≥ 0.2 mm means that the maximum depth of the second receiving groove 1711 is greater than or equal to 0.2 mm, which can provide a certain accommodation space for the seal 150. g ≤ 0.6 mm means that the maximum depth of the second receiving groove 1711 is less than or equal to 0.6 mm. This limitation can prevent the second insulator 171 from being easily disengaged, achieving a good isolation and insulation effect between the end wall 111 and the outer flange 143, and endowing the second insulator 171 with higher strength. In this embodiment, the value of g is 0.3 mm and the value of p is 0.5 mm. The upper plastic 170 in this embodiment can achieve a good isolation and insulation effect, provide a certain accommodation space for the seal 150, and improve the sealing effect.

[0070] Please refer to Figure 5 and Figure 7 , in an example of the secondary battery 100 of the present utility model, along the penetrating direction of the terminal post 140, the inner edge radius of the side of the second insulator 171 provided with the chamfer is r4. Along the radial direction of the terminal post 140, r1 - r4 ≥ 0.3 mm. In this embodiment, first, the inner edge of the side of the second insulator 171 provided with the chamfer is located radially inside the outer edge of the outer flange 143, and it is further defined that r1 - r4 ≥ 0.3 mm, that is, along the radial direction of the terminal post 140, at least 0.3 mm of the width of the second insulator 171 is directly clamped by the outer flange 143 and the end wall 111. In some embodiments, the dimension of r1 - r4 can be 0.3 mm, 0.3 mm, 0.3 mm. This setting improves the stability of the upper plastic 170 being clamped by the outer flange 143 and the end wall 111. On the one hand, it improves the insulation effect between the outer flange 143 and the end wall 111. On the other hand, the improved stability of the upper plastic 170 is also beneficial to the sealing effect of the seal 150.

[0071] Please refer to Figure 5 and Figure 7, in an example of the secondary battery 100 of the present utility model, along the direction in which the pole post 140 penetrates, the thickness of the second insulator 171 is h, where 0.5 mm ≤ h ≤ 1 mm. For example, it can be: 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1 mm. The setting of the thickness h of the second insulator 171 ≤ 1 mm reduces the gap between the outer flange 143 and the end wall 111, providing a necessary condition for improving the compression ratio of the seal 150. The setting of h ≥ 0.5 mm can ensure that the insulation effect of the second insulator 171 is not affected.

[0072] Please refer to Figure 5 and Figure 7 , in an example of the secondary battery 100 of the present utility model, the upper plastic 170 further includes a third insulator 172 integrally formed with the second insulator 171. The third insulator 172 is connected to the outer periphery of the second insulator 171 and is disposed around the outer periphery of the outer flange 143. Along the radial direction of the pole post 140, the width of the third insulator 172 is j, and j ≥ 0.5 mm. For example, it can be: 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm or 1 mm. To ensure sufficient creepage distance.

[0073] Please refer to Figure 8 , the present utility model further provides a battery pack 10. The battery pack 10 includes the secondary battery 100 of any one of the above. In an embodiment of the battery pack 10 of the present utility model, the battery pack 10 includes a box body 101, a box cover 102 and a plurality of secondary batteries 100. The plurality of secondary batteries 100 are placed in the box body 101 and are connected in series or in parallel, or in a mixed connection of series and parallel. The box cover 102 covers the box body 101 to protect the plurality of secondary batteries 100. It should be noted that in addition to the secondary battery 100 of the present utility model, the battery pack 10 may also include parts such as a battery pack thermal management system and a circuit board. The battery pack 10 may be a battery module or a battery pack, an energy storage electric cabinet, etc.; details are not elaborated here one by one.

[0074] Please refer to Figure 9, the present utility model further provides an electronic device 1, and the electronic device 1 includes the above-mentioned battery pack 10. The working part 11 is electrically connected to the battery pack 10 to obtain power support. As an example, the electronic device 1 is a vehicle, and the vehicle can be a fuel vehicle, a gas vehicle or a new energy vehicle. The new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle, etc., but is not limited thereto. The working part 11 is the vehicle body, and the battery pack 10 is arranged at the bottom of the vehicle body and provides power support for the running of the vehicle or the operation of the electrical components in the vehicle. However, in some other embodiments, the electronic device 1 can also be a mobile phone, a portable device, a laptop computer, a ship, a spacecraft, an electric toy and an electric tool, etc. The spacecraft includes an airplane, a rocket, a space shuttle and a spaceship, etc.; the working part 11 can be a unit component that can obtain the electric energy of the battery pack 10 and perform corresponding work, such as the fan blade rotation unit of a fan, the dust suction working unit of a vacuum cleaner, etc. The electric toy includes a fixed or mobile electric toy, for example, a game console, an electric vehicle 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 assembly electric tool and a railway electric tool, for example, an electric drill, an electric grinding wheel, an electric wrench, an electric screwdriver, a hammer drill, an impact electric drill, a concrete vibrator and a planer, etc. The embodiments of the present application do not impose special restrictions on the above-mentioned electronic device 1.

[0075] For the secondary battery of the present utility model, when the compression ratio w of the seal is set within the range of 20% ≤ w ≤ 50%, it can not only make the seal have a better sealing effect at normal temperature, but also achieve the effect that when the temperature of the secondary battery rises, even if the seal rebounds, it can still maintain a high sealing performance, thereby improving the technical problem of liquid leakage. Therefore, the present utility model effectively overcomes some practical problems in the prior art and thus has high utilization value and practical significance. The above embodiments are only illustrative of the principles and effects of the present utility model and are not used to limit the present utility model. Any person familiar with this technology can modify or change the above embodiments without departing from the spirit and scope of the present utility model. Therefore, all equivalent modifications or changes completed by those with ordinary knowledge in the technical field without departing from the spirit and technical idea disclosed by the present utility model should still be covered by the claims of the present utility model.

Claims

1. A secondary battery, characterized in that: include: A shell, comprising an end wall and a side wall surrounding the end wall, wherein the end wall is provided with a pole hole; An electrode assembly is disposed in the housing; A pole, penetrating the end wall and electrically connected to the electrode assembly; a seal, located between the pole and the end wall; Wherein, the compression rate w of the sealing element is in the range of 20%≤w≤50%.

2. The secondary battery according to claim 1, characterized in that: The pole includes a columnar portion, an outer flange and an inner flange, the columnar portion passes through the pole hole, the outer flange is located outside the shell, and extends from the columnar portion to the outer peripheral edge of the end wall, the inner flange is located inside the shell, and extends from the columnar portion to the outer peripheral edge of the end wall, the seal is located between the outer flange and the end wall, and along the radial direction of the pole, the ratio of the width a of the seal clamped by the outer flange and the end wall to the difference between the radius r1 of the outer flange and the radius r2 of the pole hole is i, wherein 50%≤i≤90%.

3. The secondary battery according to claim 2, characterized in that: The ratio of the difference between the radius r1 of the outer flange and the radius r3 of the columnar portion to the radius r1 of the outer flange is b, wherein 30%≤b≤50%.

4. The secondary battery according to claim 2, characterized in that: The secondary battery further includes a lower plastic, wherein the lower plastic includes a first insulator located between the pole hole and the columnar portion, and along the radial direction of the pole, a thickness c of the first insulator is in the range of 0.4 mm≤c≤0.9 mm.

5. The secondary battery according to claim 4, characterized in that: Along the direction in which the pole penetrates, the first insulator is lower than one side of the pole hole close to the outer flange and is formed with a first accommodating groove for accommodating the seal. The depth of the first accommodating groove is e, wherein 0.05mm≤e≤0.2mm.

6. The secondary battery according to claim 5, characterized in that: Along the direction in which the pole penetrates, an inner edge and an outer edge of the first insulator on a side close to the outer flange have different heights.

7. The secondary battery according to claim 6, characterized in that: Along the direction in which the pole penetrates, the distance from the inner edge to the outer flange is greater than the distance from the outer edge to the outer flange.

8. The secondary battery according to claim 2, characterized in that: The secondary battery also includes an upper plastic, which includes a second insulator clamped between the outer flange and the end wall. The second insulator is provided with a chamfer on one side close to the seal to form a second accommodating groove for accommodating the seal. Along the radial direction of the pole, the length of the chamfer is g, and along the penetrating direction of the pole, the length of the chamfer is p, wherein p≥g, 0.2mm≤g≤0.6mm.

9. The secondary battery according to claim 8, characterized in that: Along the direction in which the pole penetrates, the inner edge radius of the second insulator on one side of which the chamfer is provided is r4, and along the radial direction of the pole, r1-r4≥0.3 mm.

10. The secondary battery according to claim 8, characterized in that: Along the direction in which the pole penetrates, the thickness of the second insulator is h, wherein 0.5 mm≤h≤1 mm.

11. The secondary battery according to claim 8, characterized in that: The upper plastic also includes a third insulator integrally formed with the second insulator. The third insulator is connected to the outer periphery of the second insulator and is arranged around the outer periphery of the outer flange. Along the radial direction of the pole, the width of the third insulator is j, j≥0.5mm.

12. A battery pack, characterized in that: A secondary battery comprising the secondary battery according to any one of claims 1 to 11.

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