Battery cell and battery module

Abstract

A battery cell (100) and a battery pack, wherein the battery cell (100) comprises: a casing (110), which is provided with an accommodating cavity (111); an electrode assembly (120), which is arranged in the accommodating cavity (111); an end cover (130), which is arranged at one end of the casing (110) in a first direction and is connected to the casing (110), wherein the end cover (130) is provided with a through hole (1311); and an electrode post (150), which comprises a post body (152), a first connection portion (151) and a second connection portion (153), wherein the first connection portion (151) and the second connection portion (153) are arranged on two sides of the post body (152) in the first direction, the post body (152) is arranged in the through hole (1311) and is connected to the end cover (130), the first connection portion (151) is arranged in the accommodating cavity (111), the second connection portion (153) is located on the outer side of the end cover (130), and in a second direction, the maximum outer contour dimension of the post body (152) is D1, and the maximum outer contour dimension of the second connection portion (153) is D2, which meet 0.05≤(D2-D1) / D1≤0.65. The present application reduces the risk of a failure caused by the displacement of parts and components in the battery cell (100); thus, the safety performance of the battery cell (100) is improved.

Description

Battery cells and battery modules

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on March 8, 2024, with application number 202410264449.2 and titled “Single Cell and Battery Pack,” the entire contents of which are incorporated herein by reference. Technical Field

[0002] The embodiments of the present application relate to, but are not limited to, single cells and battery packs. Background Art

[0003] With the rapid development of mobile phones, laptops, electric vehicles, power tools, and other devices, secondary batteries with high energy density, long cycle life, and high safety performance have been widely used and developed. During battery assembly, the stability of the connection between the terminal and the top cover directly affects the battery's conductivity. If the connection is not firm, there is a risk of failure of the battery's conductive connection. Technical issues

[0004] The present application provides a single cell battery and a battery pack to improve the stability of the conductive connection of the single cell battery and reduce the risk of failure of the conductive connection of the battery. Technical Solutions

[0005] In a first aspect, a single cell battery of the present application has a first direction and a second direction intersecting each other, wherein the first direction is a height direction of the single cell battery, comprising: a housing provided with a receiving cavity;

[0006] an electrode assembly, disposed in the accommodating cavity;

[0007] an end cover, disposed at one end of the housing in the first direction and connected to the housing, the end cover having a through hole; and

[0008] An electrode post, comprising: a column, a first connecting portion, and a second connecting portion, wherein the column extends along the first direction, the first connecting portion and the second connecting portion are arranged on both sides of the column in the first direction, the column is arranged in the through hole and connected to the end cover, the first connecting portion is arranged in the accommodating cavity and electrically connected to the electrode assembly, and the second connecting portion is located outside the end cover and is used for conductive connection with an external circuit;

[0009] Wherein, along the second direction, the maximum outer contour dimension of the column is D1 mm, and the maximum outer contour dimension of the second connecting portion is D2 mm, satisfying: 0.05≤(D2-D1) / D1≤0.65.

[0010] In some embodiments, the maximum outer contour dimension D1mm of the cylinder further satisfies: 3≤D1≤15.

[0011] In some embodiments, the first connection portion and the second connection portion extend along the second direction respectively, and the first connection portion and the second connection portion are arranged on the surface of the column, and the distance from the end of the second connection portion in the second direction to the column is L1 mm, satisfying: 0.5≤L1≤5.

[0012] In some embodiments, the first connection portion and the second connection portion extend along the second direction respectively, and the first connection portion and the second connection portion are arranged on the surface of the column, and the minimum thickness of the second connection portion in the first direction is H1mm, satisfying: 0.03≤H1 / D1≤0.35.

[0013] In some embodiments, a minimum thickness H1 mm of the second connecting portion in the first direction further satisfies: 0.3≤H1≤2.

[0014] In some embodiments, the maximum outer contour dimension of the first connecting portion is D3 mm, satisfying: 0.15≤D1 / D3≤0.8.

[0015] In some embodiments, along the second direction, the maximum outer contour dimension D3 mm of the first connecting portion further satisfies: 10≤D3≤30.

[0016] In some embodiments, the single battery further includes a sealing member sleeved on the outer periphery of the column;

[0017] A first rivet is provided on the outer periphery of the column, the first rivet is provided on the outer side of the shell, and at least part of the first rivet is provided between the end cover and the second connecting portion, for positioning and fixing the pole.

[0018] In some embodiments, it further includes: a second rivet, which is arranged on the outside of the end cover, and at least a portion of the second rivet is arranged between the first rivet and the second connecting portion, and the first rivet uses the second rivet to cooperate with the second connecting portion to position and fix the pole.

[0019] In some embodiments, the present invention further comprises: a current collecting plate disposed between the first connecting portion and the electrode assembly, wherein the first connecting portion is electrically connected to the electrode assembly via the current collecting plate; and

[0020] An insulating gasket is disposed in the accommodating cavity, and the insulating gasket is disposed between the end cover and the current collecting plate.

[0021] In a second aspect, a battery pack of the present application includes a box body; and a plurality of battery cells as described above, wherein the plurality of battery cells are disposed in the box body. Beneficial effects

[0022] In the present application, the parameter relationship (D2-D1) / D1 between the maximum outer contour dimension D1mm of the column and the maximum outer contour dimension D2mm of the second connecting portion is controlled within the range of 0.05 to 0.65 to ensure that the maximum outer contour dimension D1mm of the column and the maximum outer contour dimension D2mm of the second connecting portion are reasonably designed, thereby ensuring that the structural size of the pole is reasonably designed, so that the pole can be tightly assembled and connected with other components of the single cell through the second connecting portion, thereby ensuring that the single cell is tightly assembled as a whole, reducing the risk of failure caused by displacement of components in the single cell, and ultimately improving the safety performance of the single cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0024] FIG1 is a three-dimensional structural view of a single cell provided according to an embodiment of the present application;

[0025] FIG2 is a three-dimensional structural view of a single cell provided in accordance with an embodiment of the present application from another perspective;

[0026] FIG3 is an exploded structural view of a single cell provided according to an embodiment of the present application;

[0027] FIG4 is a cross-sectional view of a single cell provided according to an embodiment of the present application;

[0028] FIG5 is a partial enlarged view of point A in FIG4 ;

[0029] FIG6 is a partial cross-sectional view of a single cell provided according to an embodiment of the present application;

[0030] FIG7 is a cross-sectional view of a pole provided according to an embodiment of the present application;

[0031] FIG8 is a cross-sectional view of a housing according to an embodiment of the present application;

[0032] FIG9 is a cross-sectional view of an end cap provided according to an embodiment of the present application;

[0033] FIG10 is a cross-sectional view of an end cap provided according to another embodiment of the present application;

[0034] FIG11 is a partial cross-sectional view of a single battery provided according to an embodiment of the present application, wherein the terminal is a solid structure;

[0035] FIG12 is a partial cross-sectional view of a single battery provided according to an embodiment of the present application, wherein the terminal has an inner groove structure;

[0036] FIG13 is a partial cross-sectional view of a single battery provided according to an embodiment of the present application, wherein the terminal has an inner groove structure;

[0037] FIG14 is a partial cross-sectional view of a single battery provided according to an embodiment of the present application, wherein the electrode is a structure having a through hole.

[0038] Explanation of the accompanying reference numerals: 100, single cell; 110, shell; 111, accommodating cavity; 120, electrode assembly; 121, negative electrode ear; 122, positive electrode ear; 130, end cover; 131, first end cover; 1311, through hole; 132, second end cover; 1321, explosion-proof scale line; 1322, liquid filling port; 1323, sealing member; 140, current collecting plate; 141, protrusion; 150, pole; 151, first connecting part; 152, column; 153, second connecting part; 160, rivet unit; 161, seal; 162, first rivet; 163, second rivet; 170, insulating gasket; 180, negative current collecting plate.

[0039] Implementation Methods of the Application

[0040] This application provides a single battery and a battery pack. To make the purpose, technical solution, and effects of this application more clear and explicit, this application is further described in detail below with reference to the following embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application.

[0041] Secondary batteries are composed of numerous structural components. As a key component of secondary batteries, these components not only safeguard the safety and reliability of the secondary battery but also ensure the connection between the battery's internal chemical system and external modules and busbars. However, due to the various internal connections between the structural components of cylindrical secondary batteries, and the need to balance sealing and flow performance requirements, the connections between the structural components are not secure, and the electrode assembly is susceptible to vertical movement in environments such as mechanical shock, posing a risk of failure in the electrical connection between the electrode assembly, current collector, and housing.

[0042] In an embodiment of the present application, referring to FIG. 1 to FIG. 14 , the present application provides a single cell 100 . Specifically, the single cell 100 has a first direction Z and a second direction X intersecting with each other, wherein the first direction Z is a height direction of the single cell.

[0043] The single cell 100 may be a lithium-ion battery, a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited thereto.

[0044] The single battery 100 may be cylindrical, flat, rectangular or other shapes, etc. As an example, in the present application, the single battery 100 is cylindrical.

[0045] Specifically, the single cell 100 may include: a housing 110 , an electrode assembly 120 , an end cap 130 and an electrode post 150 .

[0046] Specifically, the shell 110 is provided with a accommodating cavity 111; the electrode assembly 120 is arranged in the accommodating cavity 111; the end cover 130 is arranged at one end of the shell 110 in the first direction Z, and the end cover 130 is connected to the shell 110, and the end cover 130 has a through hole 1311; the pole 150 includes: a column 152, a first connecting part 151 and a second connecting part 153, the column 152 extends along the first direction Z, the first connecting part 151 and the second connecting part 153 are arranged on both sides of the column 152 in the first direction Z, the column 152 is arranged in the through hole 1311 and is connected to the end cover 130, the first connecting part 151 is arranged in the accommodating cavity 111, and the first connecting part 151 is electrically connected to the electrode assembly 120, the second connecting part 153 is located on the outside of the end cover 130, and the second connecting part 153 is used for conductive connection with an external circuit.

[0047] Among them, the single cell 100 may also include an electrolyte and other functional components. The electrolyte may be a conventional electrolyte or a special electrolyte with additives added. The electrolyte is used to soak the electrode assembly 120. Among them, the electrode assembly 120 is a component in the single cell 100 where the electrochemical reaction occurs, and there may be one or more electrode assemblies 120. The electrode assembly 120 is mainly formed by winding a positive electrode sheet, a diaphragm and a negative electrode sheet. The parts of the positive electrode sheet and the negative electrode sheet with active substances constitute the main body of the electrode assembly 120, and the parts of the positive electrode sheet and the negative electrode sheet without active substances each constitute a tab. During the charge and discharge process of the single cell 100, the positive electrode active substance and the negative electrode active substance react with the electrolyte, and the tab is connected to the pole 150 to form a current loop.

[0048] Among them, the end cover 130 can be integrally formed with the shell 110, and the end cover 130 can also be separately provided with the shell 110, and fixedly connected to one end of the shell 110 in the first direction Z by a process such as welding. This is not specifically limited in this application, and can be specifically provided according to actual circumstances. In an exemplary embodiment, the end cover 130 includes: a first end cover 131 and a second end cover 132, the first end cover 131 is provided at one end of the shell 110 in the first direction Z, and the first end cover 131 is integrally formed with the shell 110, and the first end cover 131 has a through hole 1311, and the column 152 is provided in the through hole 1311 and is connected to the first end cover 131; the second end cover 132 and the shell 110 are separately provided, and fixedly connected to the other end of the shell 110 in the first direction Z by a welding process.

[0049] The column 152, the first connecting portion 151 and the second connecting portion 153 can be integrally formed, or the first connecting portion 151 and the second connecting portion 153 can be separately provided from the column 152 and fixedly connected to the column 152 by welding. This is not specifically limited in this application and can be specifically provided according to actual circumstances.

[0050] In some embodiments, along the second direction X, the maximum outer dimension of the column 152 is D1 mm, and the maximum outer dimension of the second connecting portion 153 is D2 mm, satisfying the following: 0.05 ≤ (D2 - D1) / D1 ≤ 0.65. That is, (D2 - D1) / D1 can be controlled within the range of 0.05 to 0.65. For example, (D2 - D1) / D1 can be one of 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, or 0.65, or a range consisting of any two of them. For example, the ranges of both can be: 0.05 ≤ (D2 - D1) / D1 ≤ 0.2, 0.2 ≤ (D2 - D1) / D1 ≤ 0.4, or other ranges. It is worth noting that the above specific numerical values ​​of (D2-D1) / D1 are given for example only, and any value within the range of 0.05 to 0.65 is within the protection scope of this application.

[0051] The maximum outer dimension D1mm of the column 152 and the maximum outer dimension D2mm of the second connecting portion 153 in an actual single battery cell 100 can be obtained by disassembling the single battery cell 100, measuring the outer dimensions of the column 152 and the second connecting portion 153 on the terminal 150 at different locations in the first direction Z multiple times using a measuring tool, and calculating the average value. For example, the maximum outer dimension D1mm of the column 152 can be obtained by measuring the outer dimensions of the two opposite ends of the column 152 in the first direction Z and the outer dimensions of the central region of the column 152 in the first direction Z, and calculating the average value to obtain the maximum outer dimension D1mm of the column 152. The maximum outer dimension D2mm of the second connecting portion 153 can be obtained by measuring the outer dimensions of the two opposite ends of the second connecting portion 153 in the first direction Z and the outer dimensions of the central region of the second connecting portion 153 in the first direction Z, and calculating the average value to obtain the maximum outer dimension D2mm of the second connecting portion 153. The measuring tool may be a micrometer or a vernier caliper, but is not limited thereto.

[0052] It can be understood that in this application, the parameter relationship (D2-D1) / D1 between the maximum outer contour dimension D1mm of the column 152 and the maximum outer contour dimension D2mm of the second connecting part 153 is controlled within the range of 0.05 to 0.65 to ensure that the maximum outer contour dimension D1mm of the column 152 and the maximum outer contour dimension D2mm of the second connecting part 153 are reasonably designed, thereby ensuring that the structural size of the pole 150 is reasonably designed, so that the pole 150 can be tightly assembled and connected with other components of the single cell 100 through the second connecting part 153, thereby ensuring that the single cell 100 is tightly assembled as a whole, reducing the risk of displacement of components in the single cell 100 and causing failure, and ultimately improving the safety performance of the single cell 100.

[0053] The maximum outer dimension D1mm of the column 152 also satisfies the following: 3 ≤ D1 ≤ 15. That is, the maximum outer dimension D1mm of the column 152 can be controlled within the range of 3 to 15mm. For example, the maximum outer dimension D1mm of the column 152 can be within the range of 3mm, 4mm, 5mm, 6mm, 7mm, 8mm, 9mm, 10mm, 11mm, 12mm, 13mm, 14mm, or 15mm, or any two thereof. It is worth noting that the above-mentioned specific values ​​for the maximum outer dimension D1mm are provided for illustrative purposes only; any value within the range of 3 to 15mm is within the scope of protection of this application. By controlling the maximum outer dimension D1mm of the column 152 within the range of 3 to 15mm, this application ensures that the column 152 of the terminal 150 has a certain strength, ensuring a tight fit and connection between the terminal 150 and other components of the cell 100, thereby ensuring a tight fit within the cell 100 and reducing the risk of cell 100 failure.

[0054] In one embodiment, the first connection portion 151 and the second connection portion 153 extend along the second direction X and protrude from the surface of the column 152 .

[0055] The distance L1mm between the end of the second connecting portion 153 in the second direction X and the column 152 satisfies: 0.375≤L1≤4.5. That is, the distance L1mm between the end of the second connecting portion 153 in the second direction X and the column 152 can be controlled within the range of 0.375 to 4.5mm. For example, the distance L1mm between the end of the second connecting portion 153 in the second direction X and the column 152 can be 0.375mm, 0.5mm, 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm or 4.5mm, or a range consisting of any two of them. It is worth noting that the above-mentioned specific numerical value of the distance L1mm is given for example only, and any value within the range of 0.375 to 4.5mm is within the scope of protection of this application.

[0056] The distance between the end of the second connection portion 153 in the second direction X and the column 152 is specifically the vertical distance between the end of the second connection portion 153 in the second direction X and the outer surface of the column 152 .

[0057] The actual distance L1 mm between the end of the second connection portion 153 in the second direction X and the column 152 in the single battery 100 can be obtained by disassembling the single battery 100, measuring the distance between the end of the second connection portion 153 in the second direction X and the column 152 multiple times with a measuring tool, and calculating the average value.

[0058] For example, the maximum outer dimension D1 mm of the column 152 is obtained by measuring the thickness of the second connecting portion 153 of the pole 150 at opposite ends in the second direction X, and measuring the thickness of the second connecting portion 153 in the middle region in the second direction X, and calculating the average value. The measuring tool may be, but is not limited to, a ruler or a vernier caliper.

[0059] The present application controls the distance L1mm between the end of the second connecting portion 153 in the second direction X and the column 152 within the range of 0.375 to 4.5mm to ensure that the second connecting portion 153 has a certain length, thereby ensuring sufficient contact area between the second connecting portion 153 and other components, ensuring that the pole 150 is tightly assembled and connected with other components of the single cell 100, and ultimately ensuring that the single cell 100 is tightly assembled as a whole, reducing the risk of failure caused by displacement of components in the single cell 100.

[0060] In one embodiment, the first connecting portion 151 and the second connecting portion 153 each extend along the second direction X and protrude from the surface of the column 152. The minimum thickness of the second connecting portion 153 in the first direction Z is H1 mm, satisfying the following relationship: 0.03 ≤ H1 / D1 ≤ 0.35. That is, the ratio of the minimum thickness H1 mm of the second connecting portion 153 in the first direction Z to the maximum outer dimension D1 mm of the column 152 can be controlled within the range of 0.03 to 0.35. For example, the ratio of the minimum thickness H1 mm of the second connecting portion 153 in the first direction Z to the maximum outer dimension D1 mm of the column 152 can be within the range of 0.03, 0.05, 0.1, 0.15, 0.2, 0.25, 0.3, or 0.35, or any two thereof. In the present application, the ratio of the minimum thickness H1mm of the second connecting portion 153 in the first direction Z to the maximum outer contour dimension D1mm of the column 152 is controlled within the range of 0.03 to 0.35, so as to reasonably design the thickness of the second connecting portion 153 according to the outer diameter of the column 152, thereby ensuring the rationality of the design of the various structural dimensions of the pole 150, ensuring that the pole 150 has excellent conductive effect and can be tightly assembled and connected with other components, further reducing the risk of displacement of components in the single battery 100 and causing failure.

[0061] The minimum thickness H1mm of the second connecting portion 153 in the first direction Z can be obtained by disassembling the battery cell 100 and measuring the thickness of the second connecting portion 153 on the terminal 150 at different locations in the second direction X multiple times using a measuring tool, and calculating the average value. For example, the thickness of the second connecting portion 153 at opposite ends of the terminal 150 in the second direction X and the thickness of the middle region of the second connecting portion 153 in the second direction X can be measured using a measuring tool, and the average value can be calculated. The measuring tool can be, but is not limited to, a ruler or a vernier caliper.

[0062] In one embodiment, the thickness H1mm of the second connecting portion 153 in the first direction Z also satisfies the following condition: 0.3 ≤ H1 ≤ 2. That is, the thickness H1mm of the second connecting portion 153 in the first direction Z can be controlled within the range of 0.3 to 2mm. For example, the thickness H1mm of the second connecting portion 153 in the first direction Z can be 0.3mm, 0.5mm, 0.8mm, 1mm, 1.2mm, 1.4mm, 1.6mm, 1.8mm, or 2mm, or a range consisting of any two of these. It is worth noting that the above-mentioned specific values ​​for the thickness H1mm are provided for illustrative purposes only; any value within the range of 0.3 to 2mm is within the scope of protection of this application. By controlling the thickness H1mm of the second connecting portion 153 in the first direction Z within the range of 0.3 to 2mm, this application ensures that the second connecting portion 153 has a certain strength, thereby ensuring a secure connection between the second connecting portion 153 and other components, allowing for a tight assembly and connection with other components, further reducing the risk of component displacement within the battery cell 100, which could lead to failure.

[0063] In one embodiment, the maximum outer dimension of the first connecting portion 151 is D3 mm, satisfying the following: 0.15 ≤ D1 / D3 ≤ 0.8. That is, the ratio of the maximum outer dimension D1 mm of the column 152 to the maximum outer dimension D3 mm of the first connecting portion 151 can be controlled within the range of 0.15 to 0.8. For example, the ratio of the maximum outer dimension D1 mm of the column 152 to the maximum outer dimension D3 mm of the first connecting portion 151 can be within the range of 0.15, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, or 0.8, or any two thereof. It is worth noting that the above-mentioned specific values ​​of D1 / D3 are given for illustrative purposes only, and any value within the range of 0.15 to 0.8 is within the scope of protection of this application. The present application controls the ratio of the maximum outer contour dimension D1mm of the column 152 to the maximum outer contour dimension D3mm of the first connecting portion 151 within the range of 0.15 to 0.8, so as to reasonably design the outer diameter of the first connecting portion 151 according to the outer diameter of the column 152, thereby ensuring the rationality of the design of each structural dimension of the pole 150, ensuring that the pole 150 has excellent conductive effect and can be tightly assembled and connected with other components.

[0064] The measurement method of the maximum outer dimension D3 mm of the first connection portion 151 is the same as the measurement method of the maximum outer dimension D1 mm of the column 152 , which will not be elaborated here, and reference may be made to the above description.

[0065] In one embodiment, the maximum outer dimension D3mm of the first connecting portion 151 also satisfies the following: 10≤D3≤30. That is, the maximum outer dimension D3mm of the first connecting portion 151 can be controlled within the range of 10 to 30 mm. For example, the maximum outer dimension D3mm of the first connecting portion 151 can be one of 10 mm, 12 mm, 14 mm, 16 mm, 18 mm, 20 mm, 22 mm, 24 mm, 26 mm, 28 mm, or 30 mm, or a range consisting of any two of them. It is worth noting that the above-mentioned specific numerical values ​​of the maximum outer dimension D3mm are given for example only, and any value within the range of 10 to 30 mm is within the scope of protection of this application. By controlling the maximum outer dimension D3mm of the first connecting portion 151 within the range of 10 to 30 mm, this application ensures that the pole 150 has excellent conductive effect while being tightly assembled and connected with other components.

[0066] In order to better fix the pole 150 , in one embodiment, the single battery 100 further includes a sealing member 161 and a first rivet 162 .

[0067] Specifically, the sealing member 161 is sleeved on the outer periphery of the column 152; the first rivet 162 is disposed on the outer periphery of the column 152, the first rivet 162 is disposed on the outer side of the housing 110, and at least a portion of the first rivet 162 is disposed between the end cover 130 and the second connecting portion 153;

[0068] The sealing member 161 can be made of an insulating material. For example, the sealing member 161 can be a rubber sealing ring, but is not limited thereto.

[0069] The first rivet 162 can be made of an insulating material. For example, the first rivet 162 is made of plastic, but is not limited thereto.

[0070] It can be understood that in the present application, a seal 161 is provided between the column 152 of the pole 150 and the end cover 130 to ensure a sealed and insulated arrangement between the pole 150 and the end cover 130 to prevent short circuit between the two. At the same time, a first rivet 162 is provided between the end cover 130 and the second connecting portion 153 to form a riveted structure between the first rivet 162 and the second connecting portion 153 to rivet and fix the pole 150, thereby tightly assembling the entire single cell 100 and reducing the risk of displacement of components in the single cell 100 and causing failure. In addition, the first rivet 162 is provided on the outside of the shell 110 to avoid the first rivet 162 occupying the internal space of the shell 110, thereby increasing the space occupancy rate of the electrode assembly 120 in the shell 110 and thereby increasing the energy density of the single cell 100.

[0071] In one embodiment, the single battery 100 further includes: a second rivet 163, which is disposed on the outside of the end cover 130, and at least a portion of the second rivet 163 is disposed between the first rivet 162 and the second connecting portion 153. The first rivet 162 utilizes the second rivet 163 to cooperate with the second connecting portion 153 to position and fix the terminal 150.

[0072] The second rivet 163 can be made of an insulating material. For example, the second rivet 163 is made of plastic, but is not limited thereto.

[0073] In one embodiment, the single cell 100 further includes: a current collecting disc 140 and an insulating gasket 170, wherein the current collecting disc 140 is arranged between the first connecting portion 151 and the electrode assembly 120, and the first connecting portion 151 is electrically connected to the electrode assembly 120 via the current collecting disc 140; the insulating gasket 170 is arranged in the accommodating cavity 111, and the insulating gasket 170 is arranged between the end cover 130 and the current collecting disc 140. Specifically, the insulating gasket 170 is arranged between the first end cover 131 and the current collecting disc 140, and is used to isolate the first end cover 131 from the current collecting disc 140 to prevent contact between the two from causing a short circuit in the single cell.

[0074] For example, the current collecting plate 140 can be a positive electrode current collecting plate or a negative electrode current collecting plate. In the present application, the current collecting plate 140 is a positive electrode current collecting plate, and the current collecting plate 140 is electrically connected to the positive electrode tab 122 of the electrode assembly 120.

[0075] The single cell 100 further includes a negative electrode current collecting plate 180 , which is disposed between the second end cap 132 and the electrode assembly 120 . The negative electrode tab 121 of the electrode assembly 120 is electrically connected to the negative electrode current collecting plate 180 .

[0076] In the embodiments of the present application, please refer to Figures 4 and 5. The pole 150 can be a structure with an external groove, and the current collecting disc 140 is a flat-plate current collecting disc. Please refer to Figure 11. The pole 150 can be a solid structure, and the current collecting disc 140 is a flat-plate current collecting disc. Please refer to Figures 12 and 13. The pole 150 can be a structure with an internal groove, and the current collecting disc 140 can be a current collecting disc with a protrusion 141, so that the two can cooperate with each other in positioning. Please refer to Figure 14. The pole 150 can be a structure with a through hole, and the current collecting disc 140 can be a current collecting disc with a protrusion 141, so that the two can cooperate with each other in positioning. This application does not make specific restrictions and can be selected according to actual circumstances.

[0077] In one embodiment, the second end cap 132 is provided with an explosion-proof scoreline 1321 to form an explosion-proof valve. Specifically, referring to FIG9 , the explosion-proof scoreline 1321 may be provided on the outer wall of the second end cap 132 on the side away from the accommodating chamber 111 in the first direction Z. Referring to FIG10 , the explosion-proof scoreline 1321 may also be provided on the outer wall of the second end cap 132 on the side closer to the accommodating chamber 111 in the first direction Z to reduce external corrosion and damage. This is not specifically limited in this application and may be provided based on actual circumstances.

[0078] The explosion-proof marking line 1321 may be in a "C" shape or an "O" shape, but is not limited thereto.

[0079] In one embodiment, the present application is not limited to providing an explosion-proof scoreline 1321 on the second end cover 132 to ensure the safety performance of the single cell 100. Other mechanical mechanisms, for example, directly providing an explosion-proof valve on the second end cover 132, etc., can also achieve the corresponding functions and should also be regarded as embodiments of the present application.

[0080] Furthermore, in one embodiment, referring to FIG. 3 and FIG. 9 to FIG. 10 , the second end cover 132 is provided with a liquid injection port 1322 for injecting electrolyte.

[0081] The second end cap 132 is further provided with a sealing member 1323, which is disposed at the liquid injection port 1322 to seal the liquid injection port 1322. Specifically, after the electrolyte injection is completed, the sealing member 1323 can be used to seal the liquid injection port 1322 to seal the single cell 100 and ensure normal use of the single cell 100.

[0082] On the other hand, in an embodiment of the present application, the present application further provides a battery pack, including a box; and a plurality of single cells 100 provided in any of the above embodiments, wherein the plurality of single cells 100 are housed in the box.

[0083] On the other hand, in an embodiment of the present application, the present application further provides an electrical device, including: a battery pack as described above, the battery pack serving as a power supply for the electrical device. The electrical device may be, but is not limited to, a mobile device (e.g., a mobile phone, a laptop computer, etc.), an electric vehicle (e.g., a pure electric vehicle, a hybrid electric vehicle, a plug-in hybrid electric vehicle, an electric bicycle, an electric scooter, an electric golf cart, an electric truck, etc.), an electric train, a ship, a satellite, an energy storage system, etc.

[0084] To better understand the technical solution of the present application, a lithium-ion battery is used as an example for further explanation.

[0085] This embodiment provides a method for preparing a lithium-ion battery, and the specific process is as follows:

[0086] 1. Preparation of positive electrode sheet

[0087] The positive electrode active material is lithium iron phosphate, the conductive agent is conductive carbon black SP, and the binder is PVDF, which are mixed in a mass ratio of 96:2:2. Then NMP is added as a solvent and mixed, and stirred until the system becomes uniform to obtain a positive electrode slurry; the positive electrode slurry is evenly coated on both sides of the positive electrode current collector aluminum foil, and then transferred to an oven for drying, and then rolled, slit, and cut into pieces to obtain a positive electrode sheet.

[0088] 2. Preparation of negative electrode sheet

[0089] The negative electrode active material graphite, the conductive agent conductive carbon black SP, the thickener CMC, and the binder SBR are mixed in a mass ratio of 96.2:1.2:1.2:1.4, and then deionized water is added as a solvent to mix and stir until the system becomes uniform to obtain a negative electrode slurry; the negative electrode slurry is evenly coated on both sides of the negative electrode collector copper foil, and then transferred to an oven for drying, and then rolled, slit, and cut to obtain a negative electrode sheet.

[0090] 3. Preparation of electrolyte

[0091] Ethylene carbonate (EC), ethyl methyl carbonate (EMC), and diethyl carbonate (DEC) were mixed in a mass ratio of 3:4:3 to obtain an organic solvent, 1 mol / L of LiPF6 was added and mixed evenly, and then vinylene carbonate, vinyl sulfate, and lithium difluorophosphate were added to prepare an electrolyte.

[0092] 4. Preparation of diaphragm

[0093] PP film is used as the separator.

[0094] 5. Preparation of lithium-ion batteries

[0095] The negative electrode sheet and the positive electrode sheet prepared by the above steps are dried and then used together with the separator to prepare a wound electrode assembly using a winding machine. The positive electrode tab and the negative electrode tab are welded to the top cover, and the welded electrode assembly with the top cover is placed in an aluminum shell for packaging; the lithium-ion battery is obtained by pouring electrolyte and forming a constant capacity.

[0096] The lithium-ion batteries of the embodiments and comparative examples were all prepared according to the above-mentioned preparation method. The structural dimensions and performance test data of the embodiments and comparative examples are shown in Table 1.

[0097] The specific test items of the batteries prepared in the examples and comparative examples are as follows:

[0098] 1. Test method for connection failure of lithium-ion batteries

[0099] At 25°C, the lithium-ion battery was allowed to rest for 30 minutes. The battery was then mounted on a vibration table and vibrated using a sinusoidal wave. A logarithmic sweep was performed from 10 Hz to 55 Hz and back to 7 Hz over 15 minutes. The vibration was performed in three directions perpendicular to the sample, with the logarithmic sweep repeated 12 times in each direction for a total of 90 minutes. The lithium-ion battery was then allowed to rest for another 30 minutes. The positive and negative terminals of the lithium-ion battery were then connected to a multimeter to check whether the battery resistance R was below the operating resistance range to determine if the battery connection had failed. If the battery resistance R was less than or equal to 1.7 mΩ, the battery connection had not failed. Conversely, if the battery resistance R was greater than 1.7 mΩ, the battery connection had failed.

[0100] Table 1 Parameters of Examples 1 to 24 and parameters and test results of Comparative Examples 1 to 2

[0101] The data in Table 1 shows that in Comparative Examples 1 and 2, the specific parameters of the terminal exceeded the parameter range specified in this application, and the lithium-ion batteries did not exhibit corresponding performance. However, in Examples 1 to 24, because the parameter relationship (D2-D1) / D1 between the maximum outer dimension D1mm of the terminal and the maximum outer dimension D2mm of the second connecting portion is controlled within the range of 0.05 to 0.65, the terminal 150 can be tightly assembled and connected to the other components of the single cell 100 through the second connecting portion 153, thereby ensuring a tight assembly of the single cell 100. Compared to Comparative Examples 1 and 2, the connection failure issue is avoided.

[0102] It can be seen that the present application defines the parameter relationship (D2-D1) / D1 of the maximum outer contour dimension D1mm of the column 152 and the maximum outer contour dimension D2mm of the second connecting portion 153 in the range of 0.05 to 0.65, the maximum outer contour dimension D1mm of the column 152 in the range of 3 to 15mm, the distance L1mm from the end of the second connecting portion 153 in the second direction X to the column 152 in the range of 0.375 to 4.5mm, the thickness H1mm of the second connecting portion 153 in the first direction Z and the maximum outer contour dimension D1mm of the column 152 in the range of 0.375 to 4.5mm, The ratio of the maximum outer dimension D1mm of the column 152 to the maximum outer dimension D3mm of the first connecting portion 151 is within the range of 0.15 to 0.8, and the maximum outer dimension D3mm of the first connecting portion 151 is within the range of 10 to 30 mm, thereby ensuring that the structure and size of the pole 150 are reasonably designed, so that the pole 150 can be tightly assembled and connected with other components of the single battery 100 through the second connecting portion 153, thereby ensuring that the single battery 100 is tightly assembled as a whole, reducing the risk of failure caused by displacement of components in the single battery 100, and ultimately improving the safety performance of the single battery 100.

[0103] In the above description, specific features, structures, materials or characteristics may be combined in any suitable manner in any one or more embodiments or examples.

[0104] The introduction provided in the above steps is only used to help understand the method, structure and core concept of the present application. For those skilled in the art, without departing from the principles of the present application, several improvements and modifications can be made to the present application, and these improvements and modifications also fall within the scope of protection of the embodiments of the present application.

Claims

1. A single battery having a first direction and a second direction intersecting each other, wherein the first direction is the height direction of the single battery, wherein: include: The housing is provided with a receiving cavity; an electrode assembly, disposed in the accommodating cavity; an end cover, disposed at one end of the housing in the first direction and connected to the housing, the end cover having a through hole; and An electrode post, comprising: a column, a first connecting portion, and a second connecting portion, wherein the column extends along the first direction, the first connecting portion and the second connecting portion are arranged on both sides of the column in the first direction, the column is arranged in the through hole and connected to the end cover, the first connecting portion is arranged in the accommodating cavity and electrically connected to the electrode assembly, and the second connecting portion is located outside the end cover and is used for conductive connection with an external circuit; Along the second direction, the maximum outer contour dimension of the column is D1 mm, and the maximum outer contour dimension of the second connecting portion is D2 mm, satisfying: 0.05≤(D2-D1) / D1≤0.

65.

2. The single cell according to claim 1, wherein: The maximum outer contour dimension D1mm of the cylinder also satisfies: 3≤D1≤15.

3. The single cell according to claim 1, wherein: The first connection portion and the second connection portion extend along the second direction respectively, and are arranged on the surface of the column. The distance between the end of the second connection portion in the second direction and the column is L1 mm, satisfying: 0.375≤L1≤4.

5.

4. The single cell according to claim 1, wherein: The first connection portion and the second connection portion extend along the second direction respectively, and are arranged on the surface of the column. The minimum thickness of the second connection portion in the first direction is H1 mm, satisfying: 0.03≤H1 / D1≤0.

35.

5. The single cell according to claim 4, wherein: The minimum thickness H1 mm of the second connecting portion in the first direction also satisfies: 0.3≤H1≤2.

6. The single cell according to claim 1, wherein: The maximum outer contour dimension of the first connecting portion is D3 mm, satisfying the following: 0.15≤D1 / D3≤0.

8.

7. The single cell according to claim 6, wherein: Along the second direction, the maximum outer contour dimension D3 mm of the first connecting portion also satisfies: 10≤D3≤30.

8. The single cell according to claim 1, wherein: The single cell further includes a sealing member sleeved on the outer periphery of the column; A first rivet is provided on the outer periphery of the column, the first rivet is provided on the outer side of the shell, and at least a portion of the first rivet is provided between the end cover and the second connecting portion, for positioning and fixing the pole.

9. The single cell according to claim 8, wherein: Also includes: The second rivet is arranged on the outside of the end cover, and at least part of the second rivet is arranged between the first rivet and the second connecting portion. The first rivet cooperates with the second connecting portion using the second rivet to position and fix the pole.

10. The single cell according to claim 1, wherein: The device further comprises: a current collecting plate disposed between the first connecting portion and the electrode assembly, wherein the first connecting portion is electrically connected to the electrode assembly via the current collecting plate; and An insulating gasket is disposed in the accommodating cavity, and the insulating gasket is disposed between the end cover and the current collecting plate.

11. A battery pack comprising cabinet; and A plurality of single cells according to any one of claims 1 to 10, wherein the plurality of single cells are arranged in the box.

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