Secondary batteries and battery packs

Abstract

Provided are a secondary battery and a battery pack that can solve the problem of the sealing performance of a sealing member between a pole and a housing decreasing due to temperature rise. [Solution] The secondary battery includes a housing, an electrode assembly, a pole, and a sealing member. The housing includes an end wall and a side wall surrounding the end wall, with a pole hole provided in the end wall. The electrode assembly is installed within the housing. The pole penetrates the end wall and is electrically connected to the electrode assembly. The sealing member is located between the pole and the end wall. By setting the compressibility w of the sealing member to be in the range of 20%≦w≦50%, the technical problem of the sealing performance of the sealing member between the pole and the housing decreasing due to temperature increases can be improved.

Description

[Technical Field]

[0001] The present invention relates to the technical field of batteries, and more particularly to secondary batteries and battery packs. [Background technology]

[0002] Currently, cylindrical batteries have been widely used in various industries due to their established production processes, high production yield, low processing costs, excellent safety performance and heat dissipation performance, etc.

[0003] Conventional cylindrical batteries typically have an insulating member between the pole and the housing to provide insulation and isolation, and are then sealed with a sealing member. However, when the temperature of the cylindrical battery rises, the insulating member undergoes thermal contraction, increasing the gap between the pole and the housing and causing repulsion in the seal ring, which reduces the sealing performance of the sealing member and, in severe cases, can even cause leakage. Summary of the Invention [Problem to be solved by the invention]

[0004] In view of the above-mentioned drawbacks of the prior art, the present invention provides a secondary battery and a battery pack that can improve the technical problem of the prior art, in which the sealing performance of the sealing member between the terminal post and the housing decreases due to the influence of temperature rise. [Means for solving the problem]

[0005] To achieve the above and other related objects, the present invention provides a secondary battery. The secondary battery includes a housing, an electrode assembly, a pole, and a seal member. The housing includes an end wall and a side wall surrounding the end wall, with a pole hole provided in the end wall. The electrode assembly is disposed within the housing. The pole passes through the end wall and is electrically connected to the electrode assembly. The seal member is positioned between the pole and the end wall. The compressibility w of the seal member is in the range of 20%≦w≦50%.

[0006] In the above-mentioned technical solution, the compressibility of the sealing member is the ratio of the difference between the initial thickness of the sealing member and the thickness after the sealing member is assembled and compressed to the initial thickness of the sealing member. By setting the compressibility of the sealing member (w) within the range of 20%≦w≦50%, the sealing member can not only exhibit excellent sealing effect at room temperature, but also maintain relatively high sealing performance even when the sealing member rebounds when the temperature of the secondary battery rises, and further improve the technical issue of leakage.

[0007] In one embodiment of the secondary battery of the present invention, the electrode post includes a columnar portion, an outer flange, and an inner flange. The columnar portion penetrates the electrode post hole. The outer flange is located outside the housing and extends from the columnar portion toward the outer peripheral edge of the end wall. The inner flange is located inside the housing and extends from the columnar portion toward the outer peripheral edge of the end wall. The sealing member is located between the outer flange and the end wall. The ratio i of the difference between the width a of the portion of the sealing member sandwiched between the outer flange and the end wall along the radial direction of the electrode post and the radius r1 of the outer flange minus the radius r2 of the electrode post hole is 50%≦i≦90%.

[0008] In the above-mentioned technical solution, the portion of the seal member sandwiched between the outer flange and the end wall is in direct contact with and can be directly compressed by the outer flange and the end wall, and is therefore the effective sealing portion of the seal ring. The difference between the outer flange radius r1 and the pole post hole radius r2 is the sealable portion that can be used to seal between the outer flange and the end wall. By setting the occupation ratio i of the length of the effective sealing portion to the length of the sealable portion to be 50%≦i≦90%, it is possible to provide installation space for the insulating member while also increasing the effective sealing length of the seal member, which is advantageous to improving the sealing performance of the seal member.

[0009] In one embodiment of the secondary battery of the present invention, the ratio b of the difference between the radius r1 of the outer flange and the radius r3 of the columnar portion is 30%≦b≦50%.

[0010] In the above-mentioned technical solution, the difference between the radius r1 of the outer flange and the radius r3 of the bar-shaped portion is the cantilever portion of the bar-shaped portion of the outer flange. By setting the ratio b in the range of 30%≦b≦50%, the size of the cantilever can be made shorter, provided that a relatively large sealing space is provided for the seal ring. This setting increases the strength of the cantilever and makes it less likely for the edge of the outer flange to lift, thereby providing a more consistent compressive force to the seal member and further improving the sealing performance of the seal member.

[0011] In one embodiment of the secondary battery of the present invention, the secondary battery further includes a lower plastic portion, the lower plastic portion including a first insulator located between the electrode post hole and the post-shaped portion, and a thickness c of the first insulator along the radial direction of the electrode post is in the range of 0.4 mm≦c≦0.9 mm.

[0012] In the above technical solution, the lower plastic is used to separate the end wall from the electrode assembly and to separate the end wall from the electrode post. Here, the first insulator is mainly used to separate the end wall from the electrode post. By setting the thickness of the first insulator to 0.4 mm or more, the pressure resistance of the first insulator can be further improved. At the same time, by limiting the thickness of the first insulator to 0.9 mm or less, the effective sealing length of the seal member can be increased, which is advantageous for improving the sealing performance of the seal member.

[0013] In one embodiment of the secondary battery of the present invention, the first insulator has a first accommodating groove formed along the direction in which the pole penetrates, the first accommodating groove being lower than the side closer to the outer flange of the pole hole and accommodating a sealing member, and the depth e of the first accommodating groove is 0.05 mm≦e≦0.2 mm.

[0014] In the above-mentioned technical solution, as the compressibility of the seal increases, the deformation of the seal also increases. The provision of the first receiving groove can accommodate a larger deformation of the seal, so that when high temperatures cause the seal to rebound, the seal can still maintain a relatively high compressibility. By making the depth of the first receiving groove 0.05 mm or more, a certain amount of space can be provided for the seal. By limiting the depth to 0.2 mm or less, the isolation and insulating effect of the first insulator against the end wall and the pole can be further improved, and the strength of the first insulator can be further increased.

[0015] In one embodiment of the secondary battery of the present invention, the inner edge and outer edge of the first insulator on the side closer to the outer flange along the direction in which the electrode post penetrates have different heights.

[0016] In the above-mentioned technical solution, by forming the bottom surface of the first receiving groove as a slope, the height of the first insulator can be increased without reducing the receiving space of the first receiving groove, thereby preventing the risk of short circuit between the pillar and the end wall when the sealing material is unevenly filled, and thereby achieving a better isolation and insulation effect.In addition, this configuration also allows the height of the sealing material to be increased in the direction in which the electrode post penetrates, which is advantageous for improving the sealing effect of the sealing material.

[0017] In one embodiment of the secondary battery of the present invention, the distance from the inner edge to the outer flange along the direction in which the electrode post penetrates is greater than the distance from the outer edge to the outer flange.

[0018] In the above-mentioned technical solution, since the wall thickness of the end wall is relatively thin, the distance from the outer edge of the first insulator to the outer flange can be set relatively short, which can increase the contact area between the first insulator and the pole post hole, which is advantageous to the stability of compression between the end wall and the first insulator.

[0019] In one embodiment of the secondary battery of the present invention, the secondary battery further includes an upper plastic, and the upper plastic includes a second insulator sandwiched between the outer flange and the end wall. A chamfer is provided on the side of the second insulator closer to the sealing member, forming a second receiving groove for receiving the sealing member. Let g be the length of the chamfer along the radial direction of the pole, and p be the length of the chamfer along the penetration direction of the pole, where p≧g and 0.2 mm≦g≦0.6 mm.

[0020] In the above technical solution, the second groove can be provided to increase the filling space for the seal. Furthermore, the second groove can be provided in the form of a chamfer to prevent the risk of short-circuiting between the outer flange and the end wall due to uneven filling of the seal. p ≥ g means that the radial length of the chamfer is equal to or less than its axial length. This arrangement prevents the second insulator from coming loose when the outer flange applies pressure to it, thereby improving the insulation between the outer flange and the end wall. Furthermore, improving the stability of the upper plastic also benefits the sealing effect of the seal. By setting the maximum depth of the second groove to 0.2 mm or more, a certain amount of space can be provided for the seal. By setting the maximum depth of the second groove to 0.6 mm or less, the second insulator can be prevented from coming loose, further improving the isolation and insulation effect between the end wall and the outer flange and increasing the strength of the second insulator.

[0021] In one embodiment of the secondary battery of the present invention, if the radius of the inner edge of the second insulator on the side where the chamfer is located along the direction in which the pole penetrates is r4, then r1-r4≧0.3 mm along the radial direction of the pole.

[0022] In the above technical solution, the inner edge of the chamfered side of the second insulator is positioned radially inward of the outer edge of the outer flange, and r1-r4 is limited to 0.3 mm. This means that at least 0.3 mm of the second insulator is directly sandwiched between the outer flange and the end wall along the radial direction of the pole. This configuration improves the stability of the upper plastic portion sandwiched between the outer flange and the end wall, thereby improving the insulating effect between the outer flange and the end wall. At the same time, the improved stability of the upper plastic portion also benefits the sealing effect of the seal.

[0023] In one embodiment of the secondary battery of the present invention, the thickness h of the second insulator along the direction in which the electrode posts penetrate is 0.5 mm≦h≦1 mm.

[0024] In the above-mentioned technical solution, by setting the thickness of the second insulator to h≦1 mm, the gap between the outer flange and the end wall is reduced, thereby providing the necessary conditions for improving the compressibility of the sealing member, and by setting h≧0.5 mm, the insulating effect of the second insulator is not affected.

[0025] In one embodiment of the secondary battery of the present invention, the upper plastic further includes a third insulator integrally molded with the second insulator. The third insulator is connected to the outer periphery of the second insulator and is disposed so as to surround the outer periphery of the outer flange. The width j of the third insulator along the radial direction of the pole is j≧0.5 mm.

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

[0027] The present invention further provides a battery pack, which includes any one of the secondary batteries described above. [Effects of the Invention]

[0028] By setting the compression rate w of the sealing member in the range of 20%≦w≦50%, the secondary battery of the present invention not only enables the sealing member to exhibit excellent sealing effect at room temperature, but also achieves the effect of still maintaining relatively high sealing performance even if the sealing member repels force when the temperature of the secondary battery rises, and further improves the technical issue of leakage. [Brief explanation of the drawings]

[0029] In order to more clearly describe the embodiments of the present invention or the technical solutions of the prior art, the following briefly introduces the accompanying drawings necessary for describing the embodiments or the prior art. Obviously, the accompanying drawings in the following description are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without any creative efforts.

[0030] [Figure 1] 1 is a structural schematic diagram of one embodiment of a secondary battery of the present invention. [Figure 2] 1 is a structural schematic diagram of an electrode assembly of one embodiment of a secondary battery of the present invention. [Figure 3] 2 is a locally enlarged view of a portion A of one embodiment of the secondary battery of the present invention in FIG. 1. FIG. [Figure 4] FIG. 4 is an enlarged view of a portion B in FIG. 3. [Figure 5] 2 is a locally enlarged view of a portion A of another embodiment of the secondary battery of the present invention in FIG. 1. FIG. [Figure 6] FIG. 6 is an enlarged view of a portion D in FIG. 5. [Figure 7] FIG. 6 is an enlarged view of a portion C in FIG. 5. [Figure 8] 1 is a schematic diagram of one embodiment of a battery pack of the present invention. [Figure 9] 1 is a schematic diagram of one embodiment of an electronic device of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0031] Hereinafter, the embodiments of the present invention will be described through specific examples. Those skilled in the art will easily understand other advantages and effects of the present invention from the contents disclosed herein. The present invention may also be implemented or applied through other different specific implementations, and the details of each item in this specification may be variously modified or changed based on different perspectives and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments may be combined with each other if there is no contradiction. It should also be understood that the technical terms used in the embodiments of the present invention are intended to describe specific implementations and do not limit the scope of protection of the present invention. In the following embodiments, test methods for which specific conditions are not specified generally follow conventional conditions or conditions proposed by various manufacturers.

[0032] When a numerical range is given in an embodiment, unless otherwise specified in the present invention, it should be understood that any numerical value between the two endpoints of each numerical range can be selected. Unless otherwise defined, all technical and scientific terms used in the present invention are consistent with the prior art knowledge and description of the present invention by those skilled in the art. Furthermore, the present invention can also be implemented using any prior art methods, devices, and materials that are similar or equivalent to the methods, devices, and materials described in the embodiments of the present invention.

[0033] It should be noted that the terms "upper," "lower," "left," "right," "middle," and "one" used in this specification are used for the purpose of facilitating the description and are not used to limit the scope of the present specification. Any change or adjustment of the relative relationship between them should be considered within the scope of the present invention if there is no substantial change in the technical content.

[0034] A secondary battery includes an electrode assembly, which is the component where the electrochemical reaction occurs in the secondary battery, and can include one or more electrode assemblies.

[0035] The secondary battery further includes a housing, a cover plate, and electrode posts. The housing includes end walls and side walls surrounding the end walls, with one end of the side walls having an opening. The electrode assembly can be assembled inside the housing through the opening. The cover plate is used to cover and seal the opening of the housing. The electrode posts pass through the end walls and are electrically connected to the electrode assembly, conducting electrical energy generated by the electrode assembly.

[0036] To reduce the risk of short circuits, it is necessary to insulate the electrode posts from the end walls and to isolate the electrode assemblies from the end walls.To reduce the risk of liquid leakage between the electrode posts and the end walls, an insulating member and a sealing member are usually installed between the electrode posts and the end walls.

[0037] The inventor discovered that in conventional secondary batteries, when the temperature rises, thermal contraction occurs in the insulating material, which increases the gap between the pole and the housing and causes repulsion in the seal ring, resulting in a deterioration in the sealing performance of the seal material and, in severe cases, even causing leakage.

[0038] In view of this, the present invention provides a technical solution that solves the technical problem of the sealing performance of the sealing material between the pole and the housing decreasing due to the influence of temperature rise by setting the compression rate w of the sealing material within the range of 20%≦w≦50%.

[0039] 1 to 9, the present invention provides a secondary battery 100. The secondary battery 100 includes a housing 110, an electrode assembly 120, a pole 140, and a sealing member 150.

[0040] Referring to FIG. 1 , the housing 110 includes an end wall 111 and a side wall 112 surrounding the end wall 111. The connection between the end wall 111 and the side wall 112 can be realized in various ways, such as by integral press molding, integral casting, or split welding, as long as a stable sealing and electrical connection can be formed. The method of surrounding the side wall 112 is not limited, and it may be cylindrical or prismatic, or may be surrounded by any other closed loop contour that matches the end wall 111. In this embodiment, the outer edge of the end wall 111 is circular, and the side wall 112 cylindrically surrounds the outer edge of the end wall 111, with a circular opening 113 formed at one end of the side wall 112 remote from the end wall 111. A chamber is formed within the housing 110, surrounded by the end wall 111 and the side wall 112, to house the electrode assembly 120, electrolyte, and other necessary battery components. Specifically, the diameter of the housing 110 can be determined based on the specific size of the electrode assembly 120, and may be, for example, 18 mm, 21 mm, 46 mm, etc. The housing 110 may be made of various materials, such as copper, iron, aluminum, steel, aluminum alloy, etc. To prevent the housing 110 from rusting during long-term use, the surface of the housing 110 may be plated with a layer of anti-rust material such as metallic nickel.

[0041] 1 and 2, the electrode assembly 120 is installed inside the casing 110 and is a component where an electrochemical reaction occurs in the secondary battery 100. One or more electrode assemblies 120 may be included in the casing 110. The electrode assembly 120 includes an electrode sheet and a separator 122, which are wound together to form a wound structure. Specifically, in this embodiment, the electrode assembly 120 includes a positive electrode sheet 121, a separator 122, and a negative electrode sheet 123 wound around the axial direction of the casing 110.

[0042] 1 and 2, the positive electrode sheet 121 includes a positive electrode current collector 1211 and a positive electrode active material layer coated on the positive electrode current collector 1211. A first coated region 1212 coated with the positive electrode active material layer and a first uncoated region 1213 not coated with the positive electrode active material layer are formed on the positive electrode current collector 1211. The first coated region 1212 and the first uncoated region 1213 are arranged along the axial direction of the casing 110. The first uncoated region 1213 extends outside the separator 122 toward one end in the height direction of the secondary battery 100 and is bent toward the axis of the casing 110 to form stacked positive electrode tabs 125.

[0043] 1 and 2, the negative electrode sheet 123 includes a negative electrode current collector 1231 and a negative electrode active material layer coated on the negative electrode current collector 1231. A second coated region 1232 coated with the negative electrode active material layer and a second uncoated region 1233 not coated with the negative electrode active material layer are formed on the negative electrode current collector 1231. The second coated region 1232 and the second uncoated region 1233 are arranged along the axial direction of the casing 110. The second uncoated region 1233 extends outside the separator 122 toward the other end in the height direction of the secondary battery 100 and is bent toward the axis of the casing 110 to form stacked negative electrode tabs 124.

[0044] 1 and 2, the separator 122 is disposed between the positive electrode sheet 121 and the negative electrode sheet 123 to separate the positive electrode active material layer from 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 may be aluminum, the positive electrode active material layer includes a positive electrode active material, which may be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The material of the negative electrode current collector 1231 may be copper, and the negative electrode active material layer includes a negative electrode active material, which may be carbon or silicon, etc. The substrate material of the separator 122 may be polypropylene (PP), polyethylene (PE), etc. To provide protection and insulation to the battery cell, the outside of the battery cell may be covered with an insulating film, which may be made of PP, PE, polyethylene terephthalate (PET), polyvinyl chloride (PVC), or other polymeric materials.

[0045] 1 and 2, further in the present invention, the positive electrode tab 125 faces the end wall 111 or the opening 113, and the negative electrode tab 124 faces the other end of the housing 110. In this embodiment, the positive electrode tab 125 faces the end wall 111 and is electrically connected to the electrode post 140, causing the electrode post 140 to be positively charged. The negative electrode tab 124 faces the opening 113 and electrically connects the housing 110 to the negative electrode tab 124, causing the housing 110 to be negatively charged. However, in other embodiments, the negative electrode tab 124 may be connected to the electrode post 140, and the positive electrode tab 125 may be connected to the housing 110.

[0046] 1 , the cover plate 130 is hermetically attached to the opening 113. The shape of the outer edge 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 attachment method of the cover plate 130 includes, but is not limited to, mechanical sealing or weld sealing. In this embodiment, the cover plate 130 is hermetically sealed onto the opening 113 using a mechanical sealing method.

[0047] 3 to 5, the electrode post 140 is fixed to the end wall 111 and electrically connected to the electrode assembly 120. Specifically, an electrode post hole 1111 is provided in the end wall 111, and the electrode post 140 is attached to the electrode post hole 1111 by penetrating therethrough and insulated from the end wall 111. One end of the electrode post 140 facing the electrode assembly 120 penetrates the end wall 111 and is electrically connected directly or indirectly to the positive electrode tab 125. The electrode post 140 may have any suitable structural form that can penetrate the end wall 111 and electrically connect to the positive electrode tab 125 of the electrode assembly 120. For example, the cross section may be circular, square, prism-shaped, or have a different shape that can achieve stable electrical conduction. The electrode post hole 1111 and the electrode post 140 correspond to each other in shape. In this embodiment, the cross section of the electrode post 140 is circular.

[0048] 3 to 5, the electrode post 140 includes a post-shaped portion 142, an outer flange 143, and an inner flange 141, and the post-shaped portion 142 passes through the electrode post hole 1111. The cross section of the post-shaped portion 142 may be circular, square, prismatic, or have other shapes that can achieve stable conductivity. For better sealing and fitting effects, the post-shaped portion 142 and the electrode post hole 1111 are preferably matched to each other. That is, the electrode post hole 1111 and the post-shaped portion 142 have corresponding shapes. In this embodiment, the cross section of the post-shaped portion 142 is circular, and the circular design is convenient for processing, assembly, and sealing.

[0049] 3 to 5, the outer flange 143 is located outside the housing 110 and extends from the columnar portion 142 toward the outer periphery of the end wall 111. The outer cross section of the outer flange 143 may be circular, rectangular, prismatic, or have other shapes that can achieve stable electrical conductivity, but is not limited thereto. The inner flange 141 is located inside the housing 110 and extends from the columnar portion 142 toward the outer periphery of the end wall 111. Specifically, the inner flange 141 is connected to one end of the columnar portion 142 that is located inside the housing 110 and extends along the side of the end wall 111 that faces the inside of the housing 110 toward the outer periphery of the end wall 111. The outer cross section of the inner flange 141 may be circular, rectangular, prismatic, or have other shapes that can achieve stable electrical conductivity, but is not limited thereto.

[0050] 3 to 6, the seal member 150 is located between the electrode post 140 and the end wall 111. The location of the seal member 150 between the electrode post 140 and the end wall 111 is not limited, and the seal member 150 may be located only between the outer flange 143 and the end wall 111, only between the pillar portion 142 and the electrode post hole 1111, only between the inner flange 141 and the end wall 111, or a combination of two or three of these three locations. As long as the gap between the electrode post 140 and the end wall 111 can be sealed using an elastic member with a certain compressibility, leakage between the electrode post 140 and the end wall 111 can be avoided. The material of the seal member 150 may be any one of soluble polytetrafluoroethylene (perfluoroalkoxy, PFA), polybutylene terephthalate (PBT), liquid crystal polymer (LCP), PP, polyphenylene sulfide (PPS), and polycarbonate (PC), but is not limited thereto.

[0051] When the temperature of the secondary battery 100 increases, thermal contraction of the insulating member occurs, increasing the gap between the electrode post 140 and the housing 110, causing repulsion of the seal ring and resulting in a deterioration in the sealing performance of the seal member 150. Considering this, the range of the compressibility w of the seal member 150 is set to 20%≦w≦50%, and may be, for example, 20%, 25%, 30%, 35%, 40%, 45%, or 50%. The compressibility of the seal member 150 is the ratio of the difference between the initial thickness of the seal member 150 and the thickness of the seal member 150 after assembly and compression to the initial thickness of the seal member 150. It should be noted that the seal member 150 is compressed after assembly. The thickness of the seal member 150 can be measured by performing CT on the secondary battery 100 or by measuring after creating a cut surface. The initial thickness of the seal member 150 may be measured before installation or after removing the seal member 150 from the secondary battery 100 and allowing it to repulse. This setting not only enables the sealing member 150 to exhibit excellent sealing effect at room temperature, but also enables the sealing member 150 to maintain relatively high sealing performance even when repulsion occurs when the temperature of the secondary battery 100 rises, and furthermore, it also improves the technical issue of liquid leakage.

[0052] 3 to 5 , in one embodiment of the secondary battery 100 of the present invention, the ratio of the width a of the portion of the electrode post 140 where the seal member 150 is sandwiched between 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 electrode post hole 1111 is i, where i is 50%≦i≦90%, and may be, for example, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, or 90%. The portion of the seal member 150 where the seal member 150 is sandwiched between 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 compressed by the outer flange 143 and the end wall 111, and is therefore an effective sealing portion of the seal ring. The difference between the radius r1 of the outer flange 143 and the radius r2 of the pole hole 1111 is a sealable portion that can be used to seal between the outer flange 143 and the end wall 111. By setting the occupation ratio i of the length of the effective sealing portion to the length of the sealable portion to be 50%≦i≦90%, it is possible to provide an arrangement space for the insulating member while at the same time increasing the effective sealing length of the seal member 150, which is advantageous in improving the sealing performance of the seal member 150.

[0053] Referring to FIG. 4 , in one embodiment of the secondary battery 100 of the present invention, the ratio b of the radius r1 of the outer flange 143 to the difference between the radius r1 of the outer flange 143 and the radius r3 of the columnar portion 142 is 30%≦b≦50%. For example, it may be 30%, 33%, 35%, 36%, 40%, 45%, 47%, or 50%. The difference between the radius r1 of the outer flange 143 and the radius r3 of the columnar portion 142 is the cantilever portion of the outer flange 143 relative to the columnar portion 142. By setting the ratio b within the range of 30%≦b≦50%, the cantilever can be made shorter while providing a relatively large sealing space for the seal ring. This setting increases the strength of the cantilever, making it less likely for the edge of the outer flange 143 to lift, thereby providing a more consistent compressive force to the seal member 150 and further improving the sealing performance of the seal member 150.

[0054] 3 to 6 , in one embodiment of the secondary battery 100 of the present invention, the secondary battery 100 further includes a lower plastic 160 that surrounds the post 142. The material of the lower plastic 160 may be any one of PP, PPS, PC, PFA, PBT, and LCP, but is not limited thereto. The lower plastic 160 includes a first insulator 161 located between the post hole 1111 and the post 142. The thickness c of the first insulator 161 along the radial direction of the post 140 is in the range of 0.4 mm≦c≦0.9 mm. For example, the thickness c may be 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, or 0.9 mm. The lower plastic 160 is used to separate the end wall 111 from the electrode assembly 120 and to separate the end wall 111 from the post 140. Here, the first insulator 161 is mainly used to separate the end wall 111 from the electrode post 140. By setting the thickness of the first insulator 161 to 0.4 mm or more, the pressure resistance of the first insulator 161 can be further improved, and at the same time, by limiting the thickness of the first insulator 161 to 0.9 mm or less, the effective sealing length of the seal member 150 is increased, which is advantageous for improving the sealing performance of the seal member 150.

[0055] 3 to 6 , considering that an increase in the compressibility of the sealing member 150 increases the corresponding deformation of the sealing member 150, in one embodiment of the secondary battery 100 of the present invention, the first insulator 161 is formed with a first accommodating groove 1611 along the direction in which the pole 140 penetrates, lower than the side closer to the outer flange 143 of the pole hole 1111 to accommodate the sealing member 150. The provision of the first accommodating groove 1611 can accommodate a larger deformation of the sealing member 150, so that even when the sealing member 150 rebounds due to high temperatures, the sealing member 150 can still maintain a relatively high compressibility. Furthermore, the depth of the first accommodating groove 1611 is e, which is in the range of 0.05 mm≦e≦0.2 mm. For example, the depth may be 0.05 mm, 0.07 mm, 0.1 mm, 0.12 mm, 0.15 mm, 0.17 mm, or 0.2 mm. By making the depth of the first accommodating groove 1611 0.05 mm or more, a certain amount of accommodating space can be provided for the sealing member 150, and by limiting the depth to 0.2 mm or less, the insulating effect of the first insulator 161 against the end wall 111 and the pole 140 can be further improved, and the strength of the first insulator 161 can be further increased.

[0056] 5 and 6 , considering that a gap may exist between the end wall 111 and the pillar-shaped portion 142 when the sealing member 150 is not filled uniformly, which may still result in a risk of short circuit, in one embodiment of the secondary battery 100 of the present invention, the inner and outer edges of the first insulator 161 near the outer flange 143 along the direction in which the electrode post 140 penetrates are different in height. By forming the bottom surface of the first receiving groove 1611 as a slope, the height of the first insulator 161 can be increased without reducing the receiving space of the first receiving groove 1611, thereby achieving better isolation and insulation. The side of the bottom near the electrode post hole 1111 may be lower or higher than the side near the pillar-shaped portion 142. Both of these methods are advantageous in improving the sealing effect of the sealing member 150 because they increase the height of the sealing member 150 in the direction in which the electrode post 140 penetrates.

[0057] Considering that the wall thickness of the end wall 111 is relatively thin, in one embodiment of the secondary battery 100 of the present invention, referring to Figures 5 and 7, the distance from the inner edge to the outer flange 143 along the direction in which the pole post 140 penetrates is greater than the distance from the outer edge to the outer flange 143. This setting allows for a larger contact area between the first insulator 161 and the pole post hole 1111, which is advantageous for the stability of compression between the end wall 111 and the first insulator 161.

[0058] 5 and 7 , in one embodiment of the secondary battery 100 of the present invention, the secondary battery 100 further includes an upper plastic 170, which includes a second insulator 171 sandwiched between the outer flange 143 and the end wall 111. Considering the need to prevent the risk of a short circuit occurring between the outer flange 143 and the end wall 111 when the sealing member 150 is unevenly filled along the radial direction of the pole 140, in one embodiment of the secondary battery 100 of the present invention, a chamfer is provided on the side of the second insulator 171 closest to the sealing member 150 to form a second receiving groove 1711 that receives the sealing member 150 and increases the filling space for the sealing member 150. Furthermore, providing the second receiving groove 1711 in the form of a chamfer also helps to prevent the risk of a short circuit occurring between the outer flange 143 and the end wall 111 when the sealing member 150 is unevenly filled. The chamfer may be located on the ridge of the second insulator 171 close to the outer flange 143, or on the ridge close to the end wall 111. In this embodiment, the chamfer is located on the ridge of the second insulator 171 close to the end wall 111, and the width of the second insulator 171 on the side close to the outer flange 143 is made larger than the width of the side close to the end wall 111. This further increases the contact area between the second insulator 171 and the outer flange 143, thereby improving the compressive force of the outer flange 143 against the second insulator 171.

[0059] Furthermore, the length of the chamfer along the radial direction of the terminal post 140 is g, and the length of the chamfer along the penetration direction of the terminal post 140 is p, where p≧g. p≧g means that the radial length of the chamfer is equal to or less than its axial length. This setting makes it difficult for the upper plastic 170 to come off when the outer flange 143 applies pressure to the second insulator 171. Preferably, 0.2mm≦g≦0.6mm, and the value of g may be, for example, 0.2mm, 0.25mm, 0.3mm, 0.35mm, 0.4mm, 0.45mm, 0.5mm, 0.55mm, or 0.6mm. By setting g≧0.2 mm, i.e., by setting the maximum depth of the second receiving groove 1711 to 0.2 mm or more, a certain amount of receiving space can be provided for the seal member 150. By setting g≦0.6 mm, i.e., by setting the maximum depth of the second receiving groove 1711 to 0.6 mm or less, the second insulator 171 can be prevented from coming off, thereby further improving the insulating effect between the end wall 111 and the outer flange 143 and further increasing the strength of the second insulator 171. In this embodiment, the value of g is 0.3 mm and the value of p is 0.5 mm. In this embodiment, the upper plastic 170 exhibits excellent insulating effect and can also provide a certain amount of receiving space for the seal member 150, thereby improving the sealing effect.

[0060] 5 and 7, in one embodiment of the secondary battery 100 of the present invention, the radius of the inner edge of the second insulator 171 on the chamfered side along the direction of penetration of the pole 140 is r4, and r1-r4≧0.3 mm along the radial direction of the pole 140. In this embodiment, the inner edge of the second insulator 171 on the chamfered side is positioned radially inside the outer edge of the outer flange 143, and r1-r4≧0.3 mm is further limited. That is, along the radial direction of the pole 140, a width of at least 0.3 mm of the second insulator 171 is directly sandwiched between the outer flange 143 and the end wall 111. In some embodiments, the size of r1-r4 may be 0.3 mm, 0.4 mm, or 0.5 mm. This setting improves the stability of the upper plastic 170 sandwiched between the outer flange 143 and the end wall 111, thereby improving the insulating effect between the outer flange 143 and the end wall 111, and on the other hand, improving the stability of the upper plastic 170 is also beneficial to the sealing effect of the sealing member 150.

[0061] 5 and 7, in one embodiment of the secondary battery 100 of the present invention, the thickness of the second insulator 171 along the direction in which the electrode post 140 penetrates is h, and is 0.5 mm≦h≦1 mm. For example, it may be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm. Setting the thickness of the second insulator 171 to h≦1 mm reduces the gap between the outer flange 143 and the end wall 111, providing the necessary conditions for improving the compressibility of the sealing member 150. Setting h≧0.5 mm ensures that the insulating effect of the second insulator 171 is not affected.

[0062] 5 and 7, in one embodiment of the secondary battery 100 of the present invention, the upper plastic 170 further includes a third insulator 172 integrally molded with the second insulator 171. The third insulator 172 is connected to the outer periphery of the second insulator 171 and is disposed so as to surround the outer periphery of the outer flange 143. The width of the third insulator 172 along the radial direction of the pole 140 is j, where j is greater than or equal to 0.5 mm. For example, the width may be 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm. This ensures a sufficient creepage distance.

[0063] Referring to FIG. 8 , the present invention further provides a battery pack 10. The battery pack 10 includes any one of the secondary batteries 100 described above. In one embodiment of the battery pack 10 of the present invention, the battery pack 10 includes a box 101, a box cover 102, and a plurality of secondary batteries 100. The plurality of secondary batteries 100 are arranged in the box 101 and are connected to each other in series, parallel, or a combination of series and parallel. The box cover 102 covers the box 101 and protects the plurality of secondary batteries 100. It should be noted that the battery pack 10 may include a thermal management system, a circuit board, and other components of the battery pack 10 in addition to the secondary battery 100 of the present invention. The battery pack 10 may be a battery module, a battery pack, a power storage cabinet, or the like, but each will not be described here.

[0064] Referring to FIG. 9 , the present invention further provides an electronic device 1, which includes the above-described battery pack 10. A working unit 11 is electrically connected to the battery pack 10 to obtain electrical energy support. As an example, the electronic device 1 is a vehicle, which may be a fuel-powered vehicle, a gas-powered vehicle, or a new-energy vehicle. The new-energy vehicle may be a pure electric vehicle, a hybrid vehicle, or a range-extender vehicle, but the present invention is not limited thereto. The working unit 11 is a vehicle body, and the battery pack 10 is installed at the bottom of the vehicle body and provides electrical energy support for driving the vehicle or operating electrical components inside the vehicle. However, in other embodiments, the electronic device 1 may also be a mobile phone, a portable device, a laptop, a boat, a spacecraft, an electric toy, an electric tool, or the like. Spacecraft include airplanes, rockets, space shuttles, and spacecraft. The working unit 11 may be a unit component that can obtain electrical energy from the battery pack 10 to perform corresponding work, such as a fan blade rotation unit or a vacuum cleaner dust collection unit. The electric toys include stationary or mobile electric toys, such as game consoles, electric toy cars, electric toy boats, and electric toy airplanes. The electric tools include metal cutting tools, polishing tools, assembly tools, and railway tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, electric impact drills, concrete vibrators, and electric planers. The embodiments of the present invention are not particularly limited to the electronic device 1 described above.

[0065] In the secondary battery of the present invention, the compressibility w of the sealing member is set within the range of 20%≦w≦50%, which allows the sealing member to exhibit excellent sealing effect at room temperature. Even if the sealing member experiences repulsion when the temperature of the secondary battery rises, the sealing member still maintains relatively high sealing performance. Furthermore, the technical problem of leakage can be improved. Therefore, the present invention effectively overcomes several practical problems in the prior art and has great utility and practical significance. The above-described embodiments are intended to exemplify the principles and advantages of the present invention and are not intended to limit the present invention. Those skilled in the art may modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all modifications and alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be within the scope of the claims of the present invention. [Industrial Applicability]

[0066] By setting the compression rate w of the sealing member in the range of 20%≦w≦50%, the secondary battery and battery pack of the present invention not only enable the sealing member to exhibit excellent sealing effect at room temperature, but also achieve the effect of still maintaining relatively high sealing performance even if the sealing member rebounds when the temperature of the secondary battery rises, and further improve the technical issue of the occurrence of liquid leakage. [Explanation of symbols]

[0067] 1. Electronic Devices 10 Battery pack 11 Working section Box 101 102 Box Cover 100 Secondary battery 110 Case 111 End Wall 1111 Polar hole 112 Side wall 113 Aperture 120 Electrode Assembly 121 Positive electrode sheet 1211 Positive electrode current collector 1212 1st application area 1213 1st uncoated area 122 Separator 123 Negative electrode sheet 1231 Negative electrode current collector 1232 2nd application area 1233 2nd uncoated area 124 Negative electrode tab 125 Positive electrode tab 130 Cover Plate 140 Pole Pillar 141 Inner flange 142 Columnar part 143 Outer flange 150 sealing material 160 Lower Plastic 161 First Insulator 1611 First storage trench 170 Upper plastic 171 Second Insulator 1711 Second storage trench 172 Third Insulator

Claims

1. a housing including an end wall and a side wall surrounding the end wall, the end wall having a pole hole; an electrode assembly disposed within the housing; a pole post extending through the end wall and electrically connected to the electrode assembly; a seal member positioned between the pole post and the end wall; wherein the range of the compression rate w of the sealing member is 20%≦w≦50%.

2. 2. The secondary battery according to claim 1, wherein the electrode post includes a columnar portion, an outer flange, and an inner flange, the columnar portion passes through the electrode post hole, the outer flange is located outside the housing and extends from the columnar portion toward the outer peripheral edge of the end wall, the inner flange is located inside the housing and extends from the columnar portion toward the outer peripheral edge of the end wall, the sealing member is located between the outer flange and the end wall, and a ratio i of a difference between a width a of a portion of the sealing member sandwiched between the outer flange and the end wall along the radial direction of the electrode post and a radius r1 of the outer flange minus a radius r2 of the electrode post hole satisfies the following condition: 50%≦i≦90%.

3. 3. The secondary battery according to claim 2, wherein a ratio b of the difference between the radius r1 of the outer flange and the radius r3 of the columnar portion satisfies 30%≦b≦50%.

4. 3. The secondary battery according to claim 2, further comprising a lower plastic, the lower plastic comprising a first insulator positioned between the electrode post hole and the columnar portion, and a thickness c of the first insulator along the radial direction of the electrode post being in the range of 0.4 mm≦c≦0.9 mm.

5. 5. The secondary battery according to claim 4, wherein the first insulator has a first accommodating groove formed along a direction in which the electrode post penetrates, the first insulator being lower than a side of the electrode post hole closer to the outer flange and accommodating the sealing member, and the depth e of the first accommodating groove is in the range of 0.05 mm≦e≦0.2 mm.

6. The secondary battery according to claim 5 , wherein heights of an inner edge portion and an outer edge portion of the first insulator that are closer to the outer flange are different along the direction in which the electrode post penetrates.

7. The secondary battery according to claim 6 , wherein the distance from the inner edge portion to the outer flange along the direction in which the electrode post penetrates is greater than the distance from the outer edge portion to the outer flange.

8. 3. The secondary battery according to claim 2, wherein the secondary battery further includes an upper plastic, the upper plastic including a second insulator sandwiched between the outer flange and the end wall, a chamfer provided on a side of the second insulator closer to the sealing member to form a second accommodating groove for accommodating the sealing member, and wherein, where g is the length of the chamfer along the radial direction of the pole and p is the length of the chamfer along the penetration direction of the pole, p≧g and 0.2 mm≦g≦0.6 mm.

9. 9. The secondary battery according to claim 8, wherein, when the radius of the inner edge of the second insulator on the side where the chamfer is provided along the direction in which the pole penetrates is r4, r1-r4≧0.3 mm along the radial direction of the pole.

10. 9. The secondary battery according to claim 8, wherein the thickness h of the second insulator along the direction in which the electrode post penetrates satisfies 0.5 mm≦h≦1 mm.

11. 9. The secondary battery of claim 8, wherein the upper plastic further includes a third insulator integrally molded with the second insulator, the third insulator being connected to an outer periphery of the second insulator and surrounding an outer periphery of the outer flange, and a width j of the third insulator along a radial direction of the pole is j≧0.5 mm.

12. A battery pack comprising the secondary battery according to any one of claims 1 to 11.

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