Cylindrical secondary battery and electrical device

Abstract

A cylindrical secondary battery (100) and an electrical device (1000), relating to the technical field of energy storage. The cylindrical secondary battery (100) comprises a pressure relief member (32) and a sealing member (40), the pressure relief member (32) being a conductive member. The pressure relief member (32) comprises a disc body part (321), a first protruding part (322) and a second protruding part (323). The disc body part (321) comprises a weak region (3211). In the central axis direction (X) of the disc body part, the first protruding part (322) is located at a side of the disc body part (321), and the second protruding part (323) is located at the other side of the disc body part (321). The first protruding part (322) and the second protruding part (323) protrude in the central axis direction (X) of the disc body part. The first protruding part (322) and the second protruding part (323) are embedded into the sealing member (40) so as to limit the displacement of the sealing member (40). The present application helps to improve the sealing effect of the cylindrical secondary battery (100).

Description

Cylindrical secondary batteries and electrical equipment Technical Field

[0001] This application relates to the field of energy storage technology, and in particular to a cylindrical secondary battery and an electrical device thereof. Background Technology

[0002] With the widespread application and development of cylindrical secondary batteries, consumers are placing higher demands on their energy density, lifespan, safety, and other performance characteristics. The sealing performance of cylindrical secondary batteries is one of their most important safety features.

[0003] Currently, cylindrical secondary batteries are grooved into the battery casing to form a groove structure. A subsequent upsetting process causes the casing and the sealing ring mounted on it to press against each other, forming a mechanical seal. However, there is still room for improvement in this sealing method.

[0004] Summary of the Invention

[0005] The inventors of this application have discovered that during the upsetting process, the sealing ring is easily squeezed into the housing during the process of the housing extruding the sealing ring. This can cause gaps to appear between the housing and the sealing ring or between the sealing ring and the top cover, or reduce the strong sealing area between the sealing ring and the housing or between the sealing element and the pressure relief element.

[0006] In view of this, this application provides a cylindrical secondary battery and an electrical device that can improve sealing performance.

[0007] In a first aspect, this application provides a cylindrical secondary battery, wherein the pressure relief component is a conductive member, comprising a disk body portion, a first protrusion, and a second protrusion. The disk body portion includes a weak region, and the first and second protrusions extend along the central axis of the disk body portion. The first and second protrusions are embedded in a sealing component to limit the displacement of the sealing component. The first protrusion is located on one side of the disk body portion, and the second protrusion is located on the other side of the disk body portion.

[0008] When pressure relief components are applied to cylindrical secondary batteries, during the upset sealing process of the cylindrical secondary battery casing, the sealing component of the cylindrical secondary battery is compressed. The second protrusion plays a role in preventing part of the sealing component from being compressed into the casing. This helps to reduce the gaps between the sealing component and the pressure relief component and the casing, and helps to increase the strong sealing area between the sealing component and the casing and between the sealing component and the pressure relief component, thereby improving the sealing effect of the cylindrical secondary battery.

[0009] In one or more embodiments of this application, the first convex portion and the second convex portion are annular.

[0010] In one or more embodiments of this application, the maximum outer diameter of the first protrusion is D1, the maximum outer diameter of the second protrusion is D2, the minimum inner diameter of the second protrusion is D3, and the maximum height of the second protrusion along the central axis of the main body of the disk is H3.

[0011] In one or more embodiments of this application, 0.9D1≤D2<0.95D1. When 0.9D1≤D2<0.95D1 is satisfied, on the one hand, the radial dimension of the second protrusion along the main body of the disk is not too small, which is beneficial to improving the effect of the second protrusion in suppressing the insulation part from being squeezed into the shell, and is beneficial to improving the sealing effect of the cylindrical secondary battery; on the other hand, the radial dimension of the second protrusion along the main body of the disk is not too large, which is beneficial to reducing the restriction of the second protrusion on the setting of weak areas, and is beneficial to reducing the weight of the pressure relief component.

[0012] In one or more embodiments of this application, 0.2(D2-D3)≤H3≤0.5(D2-D3) ensures that the size of the second protrusion along the central axis of the main body of the disk is not too small, which is beneficial to improving the effect of the second protrusion in suppressing the insulation part from being squeezed into the shell and improving the sealing effect of the cylindrical secondary battery. On the other hand, it ensures that the size of the second protrusion along the central axis of the main body of the disk is not too large, which is beneficial to the installation of the pressure relief part and reduces the risk of interference during installation.

[0013] In one or more embodiments of this application, the outer wall of the first protrusion includes a first wall and a second wall. The first wall is vertically connected to the main body of the disk, and the second wall is connected to the first wall. The second wall and the first wall have an included angle α, which satisfies: 120°≤α≤160°. This is beneficial for the part of the seal to be squeezed between the first protrusion and the shell, which is beneficial for reducing the gap between the seal and the top cover, which is beneficial for improving the strong sealing area between the seal and the top cover, and which is beneficial for improving the sealing effect of the cylindrical secondary battery.

[0014] In one or more embodiments of this application, the outer wall of the first protrusion includes a first wall and a second wall. The first wall is vertically connected to the main body of the disk, and the second wall is connected to the first wall. The second wall is an arc-shaped convex wall with a curvature K, where 0 ≤ K ≤ 3.5. This facilitates the compression of the sealing element between the first protrusion and the housing, reduces the gap between the sealing element and the top cover, enhances the strong sealing area between the sealing element and the top cover, and improves the sealing effect of the cylindrical secondary battery.

[0015] In one or more embodiments of this application, it is preferred that 0 ≤ K ≤ 3.3. Satisfying the above condition is beneficial to further improving the sealing effect of the cylindrical secondary battery.

[0016] In one or more embodiments of this application, the outer wall of the first protrusion includes a first wall and a second wall. The first wall is perpendicularly connected to the main body of the disk, and the second wall is connected to the first wall. Along the central axis of the main body of the disk, the height of the first protrusion is H1, and the height of the first wall is H2, where 0 ≤ H2 < H1, which is beneficial to improving the sealing effect of the cylindrical secondary battery.

[0017] A second aspect of this application provides a cylindrical secondary battery, comprising a housing housing an electrode assembly, a cover assembly installed in an open portion of the housing, and a sealing element. The cover assembly includes a top cover and a pressure relief element, the top cover being connected to the pressure relief element. The sealing element is disposed between the cover assembly and the housing, and includes a first side portion and a second side portion disposed opposite to each other. The first side portion abuts against the cover assembly, and the second side portion abuts against the housing to seal the housing. The pressure relief element is a conductive member, comprising a disc-shaped main body portion, a first protrusion, and a second protrusion. The disc-shaped main body portion includes a weak region, and the first and second protrusions extend along the central axis of the disc-shaped main body portion. The first and second protrusions are embedded in the sealing element to limit the displacement of the sealing element. The first protrusion is located on one side of the disc-shaped main body portion, and the second protrusion is located on the other side of the disc-shaped main body portion.

[0018] During the upset sealing process of the casing, the seal is compressed. The second protrusion helps to prevent part of the seal from being squeezed into the casing, which helps to reduce the gap between the seal and the pressure relief component and the casing, and helps to increase the strong sealing area between the seal and the casing and between the seal and the pressure relief component, thus improving the sealing effect of the cylindrical secondary battery.

[0019] In one or more embodiments of this application, at least a portion of the seal simultaneously abuts against the housing and the top cover, and at least a portion of the seal simultaneously abuts against the housing and the pressure relief component, which is beneficial to improving the sealing effect of the cylindrical secondary battery.

[0020] In one or more embodiments of this application, the main body of the disk and the first protrusion enclose a mounting groove. The top cover includes a fixing part and a lead-out part. The fixing part is disposed in the mounting groove and includes a first fixing wall and a second fixing wall disposed opposite to each other along the central axis of the main body of the disk. At least a portion of the sealing member abuts against both the housing and the first fixing wall, and the second fixing wall abuts against the main body of the disk. The lead-out part is connected to the fixing part, and the minimum distance between the lead-out part and the first fixing wall along the central axis of the main body of the disk is less than the minimum distance between the lead-out part and the second fixing wall.

[0021] In one or more embodiments of this application, the maximum outer diameter of the second protrusion is D2, the minimum inner diameter of the second protrusion is D3, and the minimum inner diameter of the housing is E, where D3≤E≤D2. This is beneficial for increasing the sealing area between the seal and the housing, increasing the sealing area between the seal and the pressure relief component, and improving the sealing effect of the cylindrical secondary battery.

[0022] In one or more embodiments of this application, the maximum outer diameter of the first protrusion is D1, and the maximum height of the second protrusion along the central axis of the main body of the disk is H3, where 0.5%D1≤H3≤2.5%D1. This ensures that the size of the second protrusion along the central axis of the main body of the disk is not too small, which is beneficial to improving the effect of the second protrusion in suppressing the insulation part from being squeezed into the shell, and thus improving the sealing effect of the cylindrical secondary battery. On the other hand, this ensures that the size of the second protrusion along the central axis of the main body of the disk is not too large, which is beneficial to the installation of the pressure relief part and reduces the risk of interference during installation.

[0023] In one or more embodiments of this application, the maximum outer diameter of the first protrusion is D1, and the minimum distance between the second protrusion and the minimum inner diameter of the housing along the central axis of the main body of the disk is H4, where 0 < H4 ≤ 1% D1. This distance between the second protrusion and the housing facilitates the installation of the pressure relief component and reduces the risk of interference during installation. On the other hand, it ensures that the distance between the second protrusion and the housing is not too far, which helps to improve the sealing effect of the cylindrical secondary battery.

[0024] In one or more embodiments of this application, the maximum outer diameter of the first protrusion is D1, the maximum outer diameter of the second protrusion is D2, and the minimum inner diameter of the second protrusion is D3, with 0.5%D1≤(D2-D3)≤10%D1. This ensures that the radial dimension of the second protrusion along the main body of the disk is not too small, which is beneficial to improving the effect of the second protrusion in suppressing the insulation part from being squeezed into the shell and improving the sealing effect of the cylindrical secondary battery. On the other hand, this ensures that the radial dimension of the second protrusion along the main body of the disk is not too large, which is beneficial to reducing the restriction of the second protrusion on the setting of weak areas and reducing the weight of the pressure relief part.

[0025] In one or more embodiments of this application, the top cover includes a fixing part, which includes a first fixing wall and a second fixing wall disposed opposite to each other along the central axis of the main body of the disk. The distance between the first fixing wall and the second fixing wall along the central axis of the main body of the disk is H, and the height of the first protrusion is H1, satisfying 0.8H≤H1≤H. This is beneficial for increasing the sealing area between the sealing element and the first protrusion, and also beneficial for the installation of the pressure relief element, and helps to reduce the risk of interference during installation.

[0026] A third aspect of this application provides an electrical device, which includes the cylindrical secondary battery in any of the above embodiments.

[0027] The improved sealing of the cylindrical secondary battery in this application is beneficial to improving the reliability of the cylindrical secondary battery, and thus to improving the reliability of the electrical equipment. Attached Figure Description

[0028] Figure 1 is a front view of a cylindrical secondary battery provided in an embodiment of this application.

[0029] Figure 2 is a cross-sectional view of the cylindrical secondary battery along section line Ⅱ-Ⅱ in Figure 1.

[0030] Figure 3 is a magnified view of part A in Figure 2.

[0031] Figure 4 is a cross-sectional view of a partial pressure relief component in Figure 3.

[0032] Figure 5 is a cross-sectional view of a partial pressure relief component provided in an embodiment of this application.

[0033] Figure 6 is a cross-sectional view of a partial pressure relief component and a partial top cover provided in an embodiment of this application.

[0034] Figure 7 is a schematic diagram of an electrical device provided in an embodiment of this application.

[0035] Key Component Symbols: Cylindrical Secondary Battery 100; Casing 10; Bottom Wall 11; Side Wall 12; First Annular Wall 121; Second Annular Wall 122; Third Annular Wall 123; Top Wall 13; Receiving Cavity 10a; Open Part 10b; Electrode Assembly 20; First Electrode Section 21; Second Electrode Section 22; Cover Assembly 30; Top Cover 31; Fixing Part 311; First Fixing Wall 3111; Second Fixing Wall 3112; Lead-out Part 312; Pressure Relief Component 32; Disc Body 321; Weak Area 3211; First Protrusion 322; Outer Side Wall 3221; First Wall 322a; Second Wall 322b; Inner Side Wall 3222; Second Protrusion 323; Mounting Groove 324; Sealing Component 40; Central Axis Direction X of Disc BodyThe cylindrical secondary battery's central axis direction X'; the radial direction Y of the main body of the disk; the main body of the equipment 200; the electrical equipment 1000. Detailed Implementation

[0036] The technical solutions of the embodiments of this application will be described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments.

[0037] It should be noted that when a component is considered to be "connected" to another component, it can be directly connected to the other component or may also have an intervening component. When a component is considered to be "placed" on another component, it can be directly placed on the other component or may also have an intervening component. The terms "top," "bottom," and similar expressions used in this article are for illustrative purposes only.

[0038] Unless otherwise stated, the term "multiple" as used herein refers to two or more.

[0039] The terms “first”, “second”, etc., are used only to distinguish different objects and should not be construed as indicating or implying relative importance or implying the quantity, specific order, or primary and secondary relationship of the indicated technical features.

[0040] The term "perpendicular" is used to describe the ideal state between two components. In actual production or use, two components may exist in a state that is approximately perpendicular.

[0041] The term "parallel" is used to describe the ideal state between two components. In actual production or use, two components may exist in a state that is approximately parallel.

[0042] It should be noted that when a parameter is greater than, equal to or less than a certain endpoint value, it should be understood that the endpoint value is allowed to have a tolerance of ±5%.

[0043] It should be understood that the dimensions and thicknesses of the components shown in the accompanying drawings are for better understanding and more convenient description, and this application is not limited to the dimensions and thicknesses shown in the accompanying drawings.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0045] Some embodiments of this application will now be described with reference to the accompanying drawings. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0046] Please refer to Figures 1 and 2. This application embodiment provides a cylindrical secondary battery 100, which includes a housing 10 and an electrode assembly 20, with the electrode assembly 20 disposed inside the housing 10.

[0047] In some embodiments, the electrode assembly 20 includes a positive electrode, a negative electrode, and a separator between the positive and negative electrodes. The positive electrode, the separator, and the negative electrode are stacked and then wound to form a wound structure.

[0048] In some embodiments, the positive electrode includes a positive current collector and a positive active material layer disposed on the positive current collector, and the negative electrode includes a negative current collector and a negative active material layer disposed on the negative current collector.

[0049] In some embodiments, both the positive current collector and the negative current collector are metal layers. As an example, the positive current collector may be a metal layer comprising at least one of aluminum, nickel, tantalum, and titanium, such as aluminum foil. The negative current collector may be a metal layer comprising at least one of copper, nickel, tantalum, and titanium, such as copper foil.

[0050] In some embodiments, the positive electrode active material layer includes a positive electrode active material, which may include at least one of lithium cobalt oxide, lithium nickel cobalt manganese oxide, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium manganese iron phosphate, or lithium manganese oxide. The negative electrode active material layer includes a negative electrode active material, which may include at least one of graphite, hard carbon, soft carbon, silicon, silicon-oxygen materials, and silicon-carbon materials.

[0051] In some embodiments, the separator is an insulating film material such as polyethylene film, polypropylene film, polyester film, or polyimide film, so as to isolate the positive electrode and the negative electrode.

[0052] In some embodiments, referring to FIG2, the electrode assembly 20 has a wound structure and includes a first electrode portion 21 and a second electrode portion 22, which are arranged along the central axis of the cylindrical secondary battery 100. One of the first electrode portion 21 and the second electrode portion 22 is a positive electrode, and the other of the first electrode portion 21 and the second electrode portion 22 is a negative electrode.

[0053] In some embodiments, along the central axis of the cylindrical secondary battery 100, a plurality of positive electrode tabs are cut from the positive electrode sheet at one end of the electrode assembly 20, and the plurality of positive electrode tabs are flattened to form a first electrode portion 21; a plurality of negative electrode tabs are cut from the negative electrode sheet at the other end of the electrode assembly 20, and the plurality of negative electrode tabs are flattened to form a second electrode portion 22.

[0054] In other embodiments, along the central axis of the cylindrical secondary battery 100, a plurality of negative electrode tabs are cut from the negative electrode sheet at one end of the electrode assembly 20, and the plurality of negative electrode tabs are flattened to form a first electrode portion 21; a plurality of positive electrode tabs are cut from the positive electrode sheet at the other end of the electrode assembly 20, and the plurality of positive electrode tabs are flattened to form a second electrode portion 22.

[0055] In some embodiments, as shown in Figures 1 and 2, the housing 10 is cylindrical.

[0056] In some embodiments, referring to FIG2, the housing 10 has a receiving cavity 10a and an open portion 10b, through which the electrode assembly 20 can be inserted into the receiving cavity 10a.

[0057] In some embodiments, referring to FIG2, the housing 10 includes a bottom wall 11, a side wall 12, and a top wall 13, which are arranged sequentially along the central axis of the cylindrical secondary battery 100. The side wall 12 is cylindrical, and the bottom wall 11, side wall 12, and top wall 13 together form a receiving cavity 10a, and the top wall 13 has an open portion 10b.

[0058] In some embodiments, the top wall 13 is formed by an upsetting process. Upsetting refers to pressing or bending the portion of the opening of the cylindrical shell 10 inward to form the top wall 13.

[0059] In some embodiments, the housing 10 is made of a conductive metal material, and one of the first electrode portion 21 and the second electrode portion 22 is in contact with the housing 10, which facilitates the introduction of the polarity of the cylindrical secondary battery 100.

[0060] In some embodiments, the receiving cavity 10a is provided with an electrolyte containing a lithium salt and a solvent. The lithium salt may be LiPF6, LiBF4, LiClO4, LiB(C6H), LiCH3SO3, LiCF3SO3, LiN(SO2CF3)2, LiC(SO2CF3)3, or LiBOB. The solvent may be a carbonate compound, a carboxylic acid ester compound, an ether compound, other organic solvents, or a combination thereof.

[0061] In some embodiments, referring to Figures 1 and 2, the cylindrical secondary battery 100 further includes a cover assembly 30 and a seal 40. The cover assembly 30 is installed on the open portion 10b of the housing 10 and includes a top cover 31 and a pressure relief member 32. The seal 40 is disposed between the cover assembly 30 and the housing 10 and includes a first side and a second side disposed opposite to each other. The first side abuts against the cover assembly 30 and the second side abuts against the housing 10 to seal the housing 10.

[0062] In some embodiments, referring to Figures 2 and 3, the pressure relief member 32 includes a disk body portion 321, a first protrusion 322, and a second protrusion 323. The disk body portion 321 includes a weak region 3211, which is configured to cause structural damage under the action of air pressure within the housing 10, allowing air within the housing 10 to escape to the outside of the housing 10 to relieve pressure. Along the central axis X of the disk body portion 321, the first protrusion 322 is located on one side of the disk body portion 321, and the second protrusion 323 is located on the other side of the disk body portion 321.

[0063] The main body 321 of the disc, the first protrusion 322, and the second protrusion 323 all contact the first side of the seal 40. During the upset sealing process of the housing 10, the seal 40 is compressed. The second protrusion 323 helps to prevent part of the seal 40 from being compressed into the housing 10, which helps to reduce the gaps between the seal 40 and the pressure relief member 32 and the housing 10, respectively. It also helps to increase the strong sealing area between the seal 40 and the housing 10 and between the seal 40 and the pressure relief member 32, thereby improving the sealing effect of the cylindrical secondary battery 100.

[0064] It should be noted that the strong sealing area can be understood as the area where the contact stress between the seal 40 and the structure in contact with it is greater than 20 MPa.

[0065] In some embodiments, the direction X of the central axis of the disk body portion 321 is parallel to or coincides with the direction of the central axis of the cylindrical secondary battery 100.

[0066] In some embodiments, the weak region 3211 may be a region with a groove, a region of a composite structure with a slightly weaker material, or a region with a thickness less than a preset range, without specific limitations.

[0067] In some embodiments, the second protrusion 323 is an arc-shaped protrusion, which is beneficial for fitting with the seal 40 and for improving the sealing effect of the cylindrical secondary battery 100.

[0068] In some embodiments, as shown in Figures 2 and 3, at least a portion of the seal 40 simultaneously abuts against the housing 10 and the top cover 31, and at least a portion of the seal 40 simultaneously abuts against the housing 10 and the pressure relief member 32, which helps to improve the sealing effect of the cylindrical secondary battery 100.

[0069] In some embodiments, referring to Figures 2 and 3, a portion of the sidewall 12 is formed by a roller groove process to form a first annular wall 121, a second annular wall 122, and a third annular wall 123 connected in sequence. Along the central axis X of the disk body 321, the first annular wall 121 and the third annular wall 123 are arranged opposite to each other. The first annular wall 121 is located between the top wall 13 and the third annular wall 123, and the second annular wall 122 connects the first annular wall 121 and the third annular wall 123.

[0070] In some embodiments, referring to Figures 2 and 3, a portion of the pressure relief member 32 is located between the top wall 13 and the first annular wall 121 along the central axis direction X of the disk body portion 321.

[0071] In some embodiments, referring to Figures 2 and 3, the top cover 31 is connected to the disk body portion 321 and the first protrusion 322. Along the central axis direction X of the disk body portion 321, part of the top cover 31 is located between the top wall 13 and the disk body portion 321, and another part of the top cover 31 is exposed from the open portion 10b of the top wall 13.

[0072] In some embodiments, referring to Figures 2 and 3, along the central axis direction X of the disk body portion 321, a portion of the seal 40 is located between the top wall 13 and the top cover 31, and a portion of the seal 40 is located between the disk body portion 321 and the first annular wall 121. Along the radial direction Y of the disk body portion 321, a portion of the seal 40 is located between the housing 10 and the first protrusion 322, and a portion of the seal 40 is located between the housing 10 and the second protrusion 323.

[0073] In some embodiments, referring to FIG3, the disk body portion 321 and the first protrusion 322 enclose a mounting groove 324. The top cover 31 includes a fixing portion 311 and a lead-out portion 312. The fixing portion 311 is disposed in the mounting groove 324. The fixing portion 311 includes a first fixing wall 3111 and a second fixing wall 3112 disposed opposite to each other along the central axis direction X of the disk body portion 321. At least a portion of the sealing member 40 abuts against both the housing 10 and the first fixing wall 3111, and the second fixing wall 3112 abuts against the disk body portion 321. The lead-out portion 312 is connected to the fixing portion 311. Along the central axis direction X of the disk body portion 321, the minimum distance between the lead-out portion 312 and the first fixing wall 3111 is less than the minimum distance between the lead-out portion 312 and the second fixing wall 3112.

[0074] In some embodiments, referring to FIG3, the first electrode portion 21 is connected to the disk body portion 321 of the pressure relief member 32, so that the top cover 31 has the same polarity as the first electrode portion 21, which is beneficial for the lead-out portion 312 to lead out the polarity of the electrode assembly 20. The sealing member 40 is an insulating material, and the second electrode portion 22 is connected to the housing 10. The housing 10 is insulated and sealed to the cover assembly 30 through the sealing member 40.

[0075] In some embodiments, the material of the seal 40 may be rubber, silicone or fluororubber, etc., which will not be listed here.

[0076] In some embodiments, please refer to FIG3, the maximum outer diameter of the first protrusion 322 is D1, the maximum outer diameter of the second protrusion 323 is D2, and 0.9D1≤D2<0.95D1.

[0077] As an example, D2 can be any one of 0.9D1, 0.91D1, 0.92D1, 0.93D1, or 0.94D1, or any value in between.

[0078] In some embodiments, referring to Figures 3 and 4, the maximum height of the second protrusion 323 along the central axis direction X of the disk body 321 is H3, and 0.2(D2-D3)≤H3≤0.5(D2-D3).

[0079] When the condition 0.2(D2-D3)≤H3≤0.5(D2-D3) is met, on the one hand, the size of the second protrusion 323 along the central axis X of the main body of the disk 321 is not too small, which is beneficial to improving the effect of the second protrusion 323 in suppressing the insulation part from being squeezed into the housing 10, and is beneficial to improving the sealing effect of the cylindrical secondary battery; on the other hand, the size of the second protrusion 323 along the central axis X of the main body of the disk 321 is not too large, which is beneficial to the installation of the pressure relief part 32 and to reducing the risk of interference during installation.

[0080] As an example, H3 can be equal to any one of 0.2(D2-D3), 0.3(D2-D3), 0.4(D2-D3), or 0.5(D2-D3), or any value in between.

[0081] In some embodiments, referring to Figures 3 and 4, along the radial direction Y of the disk body portion 321, the first protrusion 322 includes an outer sidewall 3221 and an inner sidewall 3222 disposed opposite to each other. The outer sidewall 3221 includes a first wall 322a and a second wall 322b. The first wall 322a is perpendicularly connected to the disk body portion 321, and the second wall 322b is connected to the first wall 322a. The second wall 322b and the first wall 322a have an included angle α, satisfying: 120°≤α≤160°.

[0082] When the included angle α between the second wall 322b and the first wall 322a satisfies 120°≤α≤160°, it is beneficial for a portion of the seal 40 to be squeezed between the first protrusion 322 and the housing 10, which helps to reduce the gap between the seal 40 and the top cover 31, enhances the strong sealing area between the seal 40 and the top cover 31, and improves the sealing effect of the cylindrical secondary battery 100.

[0083] As an example, α can be any one of 120°, 121°, 122°, 123°, 124°, 125°, 126°, 127°, 128°, 129°, 130°, 135°, 140°, 145°, 150°, 151°, 152°, 153°, 154°, 155°, 156°, 157°, 158°, 159°, or 160°, or any value between two of them.

[0084] In some other embodiments, referring to Figure 5, the outer wall 3221 of the first protrusion 322 includes a first wall 322a and a second wall 322b. The first wall 322a is vertically connected to the main body of the disk 321, and the second wall 322b is connected to the first wall 322a. The second wall 322b is an arc-shaped protrusion. The arc-shaped design of the second wall 322b is beneficial to improving the fit between the seal 40 and the first protrusion 322, to increasing the pressure of the seal 40 between the first protrusion 322 and the housing 10, to reducing the gap between the seal 40 and the top cover 31, to increasing the strong sealing area between the seal 40 and the top cover 31, and to improving the sealing effect of the cylindrical secondary battery 100.

[0085] In some embodiments, the second wall 322b has a curvature K, where 0 ≤ K ≤ 3.5. When the curvature K of the second wall 322b satisfies 0 ≤ K ≤ 3.5, it is beneficial for a portion of the seal 40 to be squeezed between the first protrusion 322 and the housing 10, which helps to reduce the gap between the seal 40 and the top cover 31, enhances the strong sealing area between the seal 40 and the top cover 31, and improves the sealing effect of the cylindrical secondary battery 100.

[0086] As an example, K can be any one of 0, 0.1, 1, 2, 3, 3.3, 3.4, 3.5, or K can be any value between 0, 0.1, 1, 2, 3, 3.3, 3.4, 3.5.

[0087] In some embodiments, it is preferred that 0 ≤ K ≤ 3.3.

[0088] In some embodiments, please refer to FIG4, along the central axis direction X of the disk body 321, the height of the first protrusion 322 is H1, the height of the first wall 322a is H2, 0≤H2

[0089] ​In some embodiments, referring to Figures 3 and 4, the maximum outer diameter of the second protrusion 323 is D2, the minimum inner diameter of the second protrusion 323 is D3, and the minimum inner diameter of the housing 10 is E, where D3≤E≤D2. This is beneficial for increasing the sealing area between the seal 40 and the housing 10, for increasing the sealing area between the seal 40 and the pressure relief member 32, and for improving the sealing effect of the cylindrical secondary battery 100.

[0090] In some embodiments, the minimum inner diameter E of the housing 10 is the minimum inner diameter of the second annular wall 122.

[0091] In some embodiments, referring to Figures 3 and 4, the maximum outer diameter of the first protrusion 322 is D1, along the direction X of the central axis of the disk body 321, and the maximum height of the second protrusion 323 is H3, where 0.5%D1≤H3≤2.5%D1.

[0092] When the condition 0.5%D1≤H3≤2.5%D1 is met, on the one hand, the size of the second protrusion 323 along the central axis X of the main body of the disk 321 is not too small, which is beneficial to improving the effect of the second protrusion 323 in suppressing the insulation part from being squeezed into the housing 10, and is beneficial to improving the sealing effect of the cylindrical secondary battery; on the other hand, the size of the second protrusion 323 along the central axis X of the main body of the disk 321 is not too large, which is beneficial to the installation of the pressure relief part 32 and to reducing the risk of interference during installation.

[0093] As an example, H3 can be equal to any one of 0.5%D1, 0.6%D1, 0.7%D1, 0.8%D1, 0.9%D1, 1%D1, 1.1%D1, 1.2%D1, 1.3%D1, 1.4%D1, 1.5%D1, 1.6%D1, 1.7%D1, 1.8%D1, 1.9%D1, 2%D1, 2.1%D1, 2.2%D1, 2.3%D1, 2.4%D1, or 2.5%D1, or any value in between.

[0094] In some embodiments, referring to FIG3, the maximum outer diameter of the first protrusion 322 is D1, the minimum distance between the second protrusion 323 and the minimum inner diameter of the housing 10 along the central axis direction X of the disk body 321 is H4, and 0 < H4 ≤ 1% D1.

[0095] When 0 < H4 ≤ 1% D1 ​​is satisfied, on the one hand, there is a distance between the second protrusion and the housing 10, which is beneficial for the installation of the pressure relief component 32 and helps to reduce the risk of interference during the installation process. On the other hand, the distance between the second protrusion and the housing 10 is not too far, which helps to improve the sealing effect of the cylindrical secondary battery.

[0096] In some embodiments, the minimum inner diameter of the housing 10 is a second annular wall 122.

[0097] As an example, H4 can be any one of 0.1%D1, 0.2%D1, 0.3%D1, 0.4%D1, 0.5%D1, 0.6%D1, 0.7%D1, 0.8%D1, 0.9%D1, or 1%D1, or any value in between.

[0098] In some embodiments, referring to FIG3, the maximum outer diameter of the first protrusion 322 is D1, the maximum outer diameter of the second protrusion 323 is D2, the minimum inner diameter of the second protrusion 323 is D3, and 0.5%D1≤(D2-D3)≤10%D1.

[0099] When 0.5%D1≤(D2-D3)≤10%D1 is satisfied, on the one hand, the radial dimension of the second protrusion 323 along the main body of the disk 321 is not too small, which is beneficial to improving the effect of the second protrusion 323 in suppressing the insulation part from being squeezed into the housing 10, and is beneficial to improving the sealing effect of the cylindrical secondary battery; on the other hand, the radial dimension of the second protrusion 323 along the main body of the disk 321 is not too large, which is beneficial to reducing the restriction of the second protrusion 323 on the setting of the weak area 3211, and is beneficial to reducing the weight of the pressure relief part 32.

[0100] As an example, D2-D3 can be equal to any one of 0.5%D1, 0.6%D1, 0.7%D1, 0.8%D1, 0.9%D1, 1%D1, 2%D1, 3%D1, 4%D1, 5%D1, 6%D1, 7%D1, 8%D1, 9%D1, 9.1%D1, 9.2%D1, 9.3%D1, 9.4%D1, 9.5%D1, 9.6%D1, 9.7%D1, 9.8%D1, 9.9%D1, or 10%D1, or any value in between.

[0101] In some embodiments, referring to Figures 3, 4 and 6, the distance between the first fixed wall 3111 and the second fixed wall 3112 along the central axis direction X of the disk body 321 is H, and the height of the first protrusion 322 is H1, satisfying: 0.8H≤H1≤H.

[0102] When the height H1 of the first protrusion 322 satisfies 0.8H≤H1≤H, it is beneficial to increase the sealing area between the seal 40 and the first protrusion 322, and also beneficial to the installation of the pressure relief component 32, which helps to reduce the risk of interference during installation.

[0103] As an example, H1 can be equal to any one of 0.8H, 0.81H, 0.82H, 0.83H, 0.84H, 0.85H, 0.86H, 0.87H, 0.88H, 0.89H, 0.9H, 0.91H, 0.92H, 0.93H, 0.94H, 0.95H, 0.96H, 0.97H, 0.98H, 0.99H, or H, or any value in between.

[0104] To verify the influence of the dimensions of each part of the pressure relief component 32 on the sealing performance of the cylindrical secondary battery 100, the following tests were conducted:

[0105] Battery sealing test:

[0106] Multiple sets of cylindrical batteries of the same specifications were selected for testing, with 20 cylindrical batteries in each set. The maximum diameter of the cylindrical batteries was 21mm, and all cylindrical batteries in each set underwent a upset sealing process. A drop test was performed on the cylindrical cells at a height of 1.5m. After the drop, the cylindrical batteries were observed for leakage. The number of cylindrical batteries that leaked was counted. Cylindrical cells that did not leak after the drop were considered to have passed the test; otherwise, they were considered to have failed the test. Pass rate = (Number of passes / 20) × 100%.

[0107] In the comparative example, the pressure relief component 32 includes a disk body portion 321 and a first protrusion 322, wherein the first protrusion 322 includes a first wall 322a, the first protrusion 322 does not include a second wall 322b, and the pressure relief component 32 does not include a second protrusion 323. The maximum outer diameter D1 of the first protrusion 322 is 19.4 mm, the distance H between the first fixed wall 3111 and the second fixed wall 3112 along the central axis direction X of the disk body portion 321 is 0.5 mm, and the minimum inner diameter E of the housing 10 is 17.28 mm.

[0108] In embodiments 1-38, the pressure relief component 32 includes a disk body portion 321, a first protrusion 322, and a second protrusion 323, wherein the first protrusion 322 includes a first wall 322a and a second wall 322b. The maximum outer diameter D1 of the first protrusion 322 is 19.4 mm, the distance H between the first fixed wall 3111 and the second fixed wall 3112 along the central axis direction X of the disk body portion 321 is 0.5 mm, and the minimum inner diameter E of the housing 10 is 17.28 mm.

[0109] The experimental results are shown in Table 1 below.

[0110] Table 1

[0111] Referring to Table 1 above, compared with the comparative examples, the pressure relief component 32 in Examples 1-38 includes a disc body portion 321, a first protrusion 322, and a second protrusion 323. The second protrusion 323 serves to suppress the partial compression of the seal 40 into the housing 10, which helps to reduce the gaps between the seal 40 and the pressure relief component 32 and the housing 10 respectively, and helps to increase the strong sealing area between the seal 40 and the housing 10 and between the seal 40 and the pressure relief component 32, which helps to improve the sealing effect of the cylindrical secondary battery 100.

[0112] Referring to Table 1 above, compared to Example 1, Examples 2-6 satisfy 0.5%D1≤(D2-D3), which is beneficial to improving the effect of the second protrusion 323 in suppressing the insulation part from being squeezed into the housing 10, and is beneficial to improving the sealing effect of the cylindrical secondary battery.

[0113] Referring to Table 1 above, compared with Examples 7 and 12, Examples 8-10 satisfy 0.8H≤H1≤H, which is beneficial to improving the sealing area between the seal 40 and the first protrusion 322, and thus improving the sealing effect of the cylindrical secondary battery.

[0114] Referring to Table 1 above, it can be seen that, compared with Example 15, Examples 11-14 satisfy 0≤H2

[0115] Referring to Table 1 above, compared with Examples 16 and 21, Examples 17-20 satisfy 0.5%D1≤H3≤2.5%D1, ensuring that the size of the second protrusion 323 along the central axis X of the disk body 321 is not too small. This is beneficial to improving the effect of the second protrusion 323 in suppressing the insulation part from being squeezed into the housing 10, and is beneficial to improving the sealing effect of the cylindrical secondary battery.

[0116] Referring to Table 1 above, compared with Examples 22 and 27, Examples 23-26 satisfy 0<H4≤1%D1, which allows a distance between the second protrusion 323 and the housing 10, and ensures that the distance between the second protrusion 323 and the housing 10 is not too far, which is beneficial to improving the sealing effect of the cylindrical secondary battery.

[0117] Referring to Table 1 above, compared with Examples 28 and 32, Examples 29-31 satisfy 120°≤α≤160°, which is beneficial for the portion of the seal 40 to be squeezed between the first protrusion 322 and the housing 10, which is beneficial for reducing the gap between the seal 40 and the top cover 31, which is beneficial for increasing the strong sealing area between the seal 40 and the top cover 31, and which is beneficial for improving the sealing effect of the cylindrical secondary battery 100.

[0118] ​Referring to Table 1 above, compared with Examples 33 and 38, Examples 34-37 satisfy 0≤K≤3.5, which is beneficial for the portion of the seal 40 to be squeezed between the first protrusion 322 and the shell 10, which is beneficial for reducing the gap between the seal 40 and the top cover 31, which is beneficial for increasing the strong sealing area between the seal 40 and the top cover 31, and which is beneficial for improving the sealing effect of the cylindrical secondary battery 100.

[0119] Referring to Table 1 above, in Example 39, compared to Example 17, D2 / D1 is less than 0.9, and the radial dimension of the second protrusion 323 along the main body 321 of the disk is too large. Although this can improve the sealing effect of the cylindrical secondary battery 100, it also results in the pressure relief component 32 being too heavy. In Example 40, compared to Example 17, D2 / D1 is greater than 0.95, and the radial dimension of the second protrusion 323 along the main body 321 of the disk is too small. The second protrusion 323 is not effective enough in preventing the insulating component from being squeezed into the housing 10, resulting in insufficient sealing of the cylindrical secondary battery 100.

[0120] Please refer to Figure 7. An embodiment of this application also provides an electrical device 1000, which includes the above-described cylindrical secondary battery 100.

[0121] In some embodiments, please refer to FIG7, the electrical device 1000 further includes a device body 200, and a cylindrical secondary battery 100 is installed on the device body 200 for supplying power to the device body 200.

[0122] In some embodiments, the electrical device 1000 may be a speaker, computer, e-book player, electric toy, game console, radio, lamp, or calculator, etc., which will not be listed here.

[0123] Since the electrical equipment 1000 adopts the technical solution of any embodiment of the cylindrical secondary battery 100 described above, it has at least the beneficial effects brought about by the technical solution of any embodiment of the cylindrical secondary battery 100 described above, which will not be repeated here.

[0124] Furthermore, those skilled in the art should recognize that the above embodiments are merely illustrative of this application and are not intended to limit this application. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of this application should be included within the scope of protection of this application.

Claims

A cylindrical secondary battery, characterized in that, The cylindrical secondary battery includes a pressure relief component and a sealing component. The pressure relief component is a conductive member and includes: The disk body includes a main body portion, a first protrusion, and a second protrusion. The main body portion includes a weak area. The first protrusion and the second protrusion extend along the central axis of the main body portion. The first protrusion and the second protrusion are embedded in the seal to restrict the displacement of the seal. The first protrusion is located on one side of the main body portion, and the second protrusion is located on the other side of the main body portion. The cylindrical secondary battery according to claim 1 is characterized in that, The first protrusion and the second protrusion are annular. The cylindrical secondary battery according to claim 1 or 2 is characterized in that, The maximum outer diameter of the first protrusion is D1, the maximum outer diameter of the second protrusion is D2, the minimum inner diameter of the second protrusion is D3, and the maximum height of the second protrusion along the central axis of the main body of the disk is H3. The pressure relief component satisfies at least one of the following conditions (1) and (2): (1) 0.9D1≤D2<0.95D1; (2)0.2(D2-D3)≤H3≤0.5(D2-D3). The cylindrical secondary battery according to claim 1 or 2 is characterized in that, The outer side wall of the first protrusion includes a first wall and a second wall. The first wall is vertically connected to the main body of the disk, and the second wall is connected to the first wall. The second wall and the first wall have an included angle α, which satisfies: 120°≤α≤160°. The cylindrical secondary battery according to claim 1 or 2 is characterized in that, The outer wall of the first protrusion includes a first wall and a second wall, the first wall being vertically connected to the main body of the disk, and the second wall being connected to the first wall; Along the central axis of the main body of the disk, the height of the first protrusion is H1, the height of the first wall is H2, the second wall is an arc-shaped convex wall with curvature K, and the first protrusion satisfies at least one of the following conditions (1) and (2): (1)0≤K≤3.5； (2) 0 ≤ H2 < H1. A cylindrical secondary battery, characterized in that, include: A housing containing the electrode assembly; A cover assembly installed in the open portion of the housing, the cover assembly including a top cover and a pressure relief member, the top cover being connected to the pressure relief member; a seal member disposed between the cover assembly and the housing, the seal member including a first side portion and a second side portion disposed opposite to each other, the first side portion abutting against the cover assembly and the second side portion abutting against the housing to seal the housing; The pressure relief component is a conductive component, and the pressure relief component includes: The disk body includes a main body portion, a first protrusion, and a second protrusion. The main body portion includes a weak area. The first protrusion and the second protrusion extend along the central axis of the main body portion. The first protrusion and the second protrusion are embedded in the seal to restrict the displacement of the seal. The first protrusion is located on one side of the main body portion, and the second protrusion is located on the other side of the main body portion. The cylindrical secondary battery according to claim 6 is characterized in that, At least a portion of the seal simultaneously abuts against the housing and the top cover, and at least a portion of the seal simultaneously abuts against the housing and the pressure relief element. The cylindrical secondary battery according to claim 6 is characterized in that, The main body of the disk and the first protrusion together form a mounting groove; The top cover includes a fixing part and an outlet part. The fixing part is disposed in the mounting groove. The fixing part includes a first fixing wall and a second fixing wall that are disposed opposite to each other along the central axis of the main body of the disk. At least a portion of the sealing member abuts against the housing and the first fixing wall at the same time, and the second fixing wall abuts against the main body of the disk. The lead-out portion is connected to the fixing portion, and along the central axis of the main body of the disk, the minimum distance between the lead-out portion and the first fixing wall is less than the minimum distance between the lead-out portion and the second fixing wall. The cylindrical secondary battery according to claim 6 is characterized in that, The maximum outer diameter of the first protrusion is D1, the maximum outer diameter of the second protrusion is D2, the minimum inner diameter of the second protrusion is D3, the minimum inner diameter of the housing is E, the maximum height of the second protrusion along the central axis of the main body of the disk is H3, the minimum distance between the second protrusion and the minimum inner diameter of the housing is H4, and the second protrusion satisfies any one of the following conditions (1) to (4): (1) D3≤E≤D2; (2)0.5%D1≤H3≤2.5%D1; (3) 0 < H4 ≤ 1% D1; (4)0.5%D1≤(D2-D3)≤10%D1. The cylindrical secondary battery according to claim 9 is characterized in that, The top cover includes a fixing part, which includes a first fixing wall and a second fixing wall arranged opposite to each other along the central axis of the main body of the disk. The distance between the first fixing wall and the second fixing wall along the central axis of the main body of the disk is H, and the height of the first protrusion is H1, satisfying: 0.8H≤H1≤H. An electrical appliance, characterized in that, This includes the cylindrical secondary battery as described in any one of claims 1 to 5 or the cylindrical secondary battery as described in any one of claims 6 to 10.

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