Individual batteries, battery packs and electrical devices

Abstract

The embodiments of the present application disclose a single cell, a battery pack and an electrical device, wherein the single cell comprises: a shell; and two winding cores, which are contained in the shell, each winding core is distributed along the thickness direction, and the winding core is wound by a battery pole piece and a diaphragm; the battery pole piece comprises: a pole piece body; and a plurality of pole ears, which are connected to the pole piece body; wherein the winding core has a target side surface and a folding reference surface perpendicular to the thickness direction, and a plurality of pole ears are folded in the direction close to the folding reference surface in the thickness direction; in the thickness direction, the distance between the folding reference surface and the target side surface is L1 mm, satisfying: (H‑10) / 8≤L1≤(H‑8) / 4. According to the present application, the risk of pole ear redundancy or the risk of pole ear tearing when multiple pole ears are folded is avoided, and the folding effect of the pole ears is ensured, thereby optimizing the electronic conduction path in the single cell, improving the power performance of the single cell, and finally improving the comprehensive performance of the single cell.

Description

Technical Field

[0001] The present application relates to the field of battery technology, and in particular to a single cell, a battery pack and an electrical device. Background Art

[0002] With the rapid development of mobile phones, laptops, electric vehicles, power tools, etc., lithium-ion batteries with high energy density, high cycle life and high power performance have been widely used and developed. There is an urgent need for lithium-ion batteries with larger capacity, higher power and longer battery life. The power performance of the battery is one of the core performances of the battery, so how to improve the power performance of the battery has become an urgent problem to be solved. Summary of the invention

[0003] The embodiments of the present application provide a single cell battery, a battery pack and an electrical device to improve the power performance of the single cell battery.

[0004] In order to solve the above technical problems, the embodiments of the present application disclose the following technical solutions:

[0005] In one aspect, a single cell is provided, having a thickness direction, comprising:

[0006] a housing; and

[0007] Two winding cores are contained in the shell, each of the winding cores is distributed along the thickness direction, and the winding cores are wound by winding the battery pole piece and the diaphragm;

[0008] The battery pole piece comprises: a pole piece body; and

[0009] A plurality of pole ears connected to the pole piece body;

[0010] The winding core has a target side surface and a retracted reference surface perpendicular to the thickness direction, and the plurality of tabs are retracted in a direction close to the retracted reference surface in the thickness direction;

[0011] In the thickness direction, the distance between the shrinking reference surface and the target side surface is L1 mm, satisfying: (H-10) / 8≤L1≤(H-8) / 4;

[0012] H mm is the maximum dimension of one of the winding cores in the thickness direction.

[0013] In addition to one or more of the features disclosed above, or as an alternative, the distance L1mm between the gathered reference surface and the target side surface in the thickness direction further satisfies: 0≤L1≤18; and / or,

[0014] The maximum dimension H mm of the winding core in the thickness direction satisfies: 10≤H≤80.

[0015] In addition to one or more of the features disclosed above, or as an alternative, the number of winding layers of the winding core is N1, and the number of the pole ears is N2, satisfying: N1= N2.

[0016] In addition to or as an alternative to one or more of the features disclosed above, the winding core is arranged into a first area and a second area with its center in the thickness direction as the boundary;

[0017] The number of the tabs in the first region is the same as that in the second region; or,

[0018] The difference in number of the tabs in the first region and the second region is 1.

[0019] In addition to or as an alternative to one or more of the features disclosed above, the battery electrode is any one of a positive electrode or a negative electrode.

[0020] In addition to or as an alternative to one or more of the features disclosed above, the invention further comprises: a top cover, an electrode connector and a pole;

[0021] The top cover is covered on the shell, the electrode connector and the pole are both arranged on the top cover, and the electrode connector is electrically connected between the pole ear and the pole.

[0022] On the other hand, a single cell is provided, having a thickness direction, including:

[0023] a housing; and

[0024] Four winding cores are contained in the shell, each of the winding cores is distributed along the thickness direction, and the winding cores are wound by winding the battery pole piece and the diaphragm;

[0025] The battery pole piece comprises: a pole piece body; and

[0026] A plurality of pole ears connected to the pole piece body;

[0027] The winding core has a target side surface and a retracted reference surface perpendicular to the thickness direction, and the plurality of tabs are retracted in a direction close to the retracted reference surface in the thickness direction;

[0028] In the thickness direction, the distance between the gathered reference surface and the target side surface is L1 mm, satisfying: (4×H-10) / 16≤L1≤(4×H-8) / 4;

[0029] H mm is the maximum dimension of one of the winding cores in the thickness direction.

[0030] In addition to one or more of the features disclosed above, or as an alternative, the distance L1mm between the gathered reference surface and the target side surface in the thickness direction further satisfies: 1.875≤L1≤78; and / or,

[0031] The maximum dimension H mm of the winding core in the thickness direction satisfies: 10≤H≤80.

[0032] On the other hand, a battery pack is further disclosed. In addition to or as an alternative to one or more of the features disclosed above, the battery pack includes a case; and a single cell as described in any one of the above items, wherein the single cell is accommodated in the case.

[0033] On the other hand, an electrical device is further disclosed. In addition to or as an alternative to one or more of the features disclosed above, the electrical device includes a battery pack as described above, and the battery pack serves as a power supply for the electrical device.

[0034] One of the above technical solutions has the following advantages or beneficial effects: In this application, the position of the folding reference surface is designed to be limited, that is, the thickness and number of the winding core are used to reasonably design the folding reference surface positions of multiple pole ears in different single cells, thereby avoiding the risk of pole ear redundancy or pole ear tearing when multiple pole ears are folded, ensuring the folding effect of the pole ears, thereby optimizing the electronic conduction path in the single cell, improving the power performance of the single cell, and ultimately improving the comprehensive performance of the single cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] The technical solution and other beneficial effects of the present application will be made apparent by describing in detail the specific implementation methods of the present application in conjunction with the accompanying drawings.

[0036] Figure 1 is an exploded structural view of a single cell provided according to an embodiment of the present application;

[0037] Figure 2 is a structural diagram of a winding core provided according to an embodiment of the present application;

[0038] Figure 3 This is a schematic diagram of the structure of the tabs in the winding core in a retracted state according to the first specific embodiment of the present application;

[0039] Figure 4 It is a structural schematic diagram of the pole ears in the winding core provided in the second specific embodiment of the present application in a retracted state.

[0040] Description of reference numerals:

[0041] 100. Single cell;

[0042] 110. Shell;

[0043] 120, winding core; 121, battery pole piece; 1211, pole piece body; 1212, pole ear; 122, diaphragm; 123, folding reference surface; 124, target side surface; 125, first area; 126, second area;

[0044] 130, top cover;

[0045] 140. Electrode connector;

[0046] 150. Pole. DETAILED DESCRIPTION

[0047] In order to make the purpose, technical solution and beneficial effects of this application more clear, the following further describes this application in detail in conjunction with the accompanying drawings and specific implementation methods. It should be understood that the specific implementation methods described in this specification are only for explaining this application, not for limiting this application.

[0048] In the description of the present application, it should be understood that the terms "center", "longitudinal", "lateral", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, which are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present application. In addition, the terms "first" and "second" are only used for descriptive purposes, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of technical features indicated. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. In the description of the present application, the meaning of "multiple" refers to two or more, unless otherwise clearly and specifically defined.

[0049] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "installed", "connected", and "connected" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection, a direct connection, or an indirect connection through an intermediate medium, it can be the internal connection of two elements or the interaction relationship between two elements. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0050] In the present application, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may include that the first and second features are in direct contact, or may include that the first and second features are not in direct contact but are in contact through another feature between them. Moreover, a first feature being "above", "above" and "above" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is higher in level than the second feature. A first feature being "below", "below" and "below" a second feature includes that the first feature is directly above and obliquely above the second feature, or simply indicates that the first feature is lower in level than the second feature.

[0051] With the rapid development of new energy technologies, secondary batteries are widely used in various fields such as electric vehicles, energy storage base stations, and electronic products. The demand for discharge power of secondary batteries has increased, and the design and manufacture of high-power secondary batteries has become a research direction. In order to improve the power performance of secondary batteries, multi-pole lug structures have become one of the options for high-power products. However, due to the large differences in the thickness of the cores of different secondary batteries, the power performance of secondary batteries can only be improved by increasing the number of lugs. As the number of lugs increases, secondary batteries with multi-pole lug structures are prone to lug tearing during the manufacturing process. For high-power products, lug tearing will seriously affect the discharge power of secondary batteries. The disadvantages outweigh the advantages.

[0052] In order to solve the above problems, in the embodiment of the present application, the present application provides a single cell 100, by designing the folding position of multiple tabs on the winding core when welding, so as to prevent the risk of tab redundancy or tab tearing when multiple tabs are folded, thereby optimizing the electronic conduction path in the single cell 100, improving the power performance of the single cell 100, and finally improving the comprehensive performance of the single cell 100. To this end, the embodiment of the present application provides a single cell 100, wherein: Figures 1 to 4 1 shows a schematic structural diagram of a single cell 100, wherein: Figure 3 and Figure 4 Two structures of the single battery 100 are shown respectively.

[0053] In the specific embodiment 1 of the present application:

[0054] Please refer to Figures 1 to 3 The present application provides a single cell 100, wherein the single cell 100 has a thickness direction X, a length direction Y, and a height direction Z intersecting each other. Exemplarily, the single cell 100 has a thickness direction X, a length direction Y, and a height direction Z perpendicular to each other. Here, "perpendicular" refers to a state where the angle formed by a straight line and a straight line, a straight line and a plane, or a plane and a plane is 89° to 91°.

[0055] Specifically, the single battery 100 includes: a housing 110 , a winding core 120 and a top cover 130 .

[0056] Specifically, two winding cores 120 are provided, and the two winding cores 120 are both accommodated in the shell 110. Each winding core 120 is distributed along the thickness direction X, and the winding core 120 is wound by the battery electrode 121 and the diaphragm 122. The top cover 130 is connected to the shell 110 and the top cover 130 covers the shell 110 to seal the shell 110.

[0057] Specifically, the battery electrode 121 includes: a electrode body 1211 and an electrode tab 1212 . A plurality of electrode tabs 1212 are provided, and the plurality of electrode tabs 1212 are connected to the electrode body 1211 .

[0058] The single cell 100 may be a secondary battery, which refers to a single cell that can be used continuously by activating the active material by charging after the single cell is discharged. Exemplarily, the single cell 100 may be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel metal hydride battery or a nickel cadmium battery, but is not limited thereto.

[0059] The single battery 100 may be cylindrical, flat, long, or in other shapes.

[0060] The housing 110 may be made of a strong material such as metal, but is not limited thereto. For example, the housing 110 is made of an aluminum profile, but is not limited thereto.

[0061] The battery electrode 121 can be a positive electrode or a negative electrode, which is not specifically limited in the present application and can be selected according to the actual situation. For example, when the battery electrode 121 is a positive electrode, the tab 1212 is a positive tab; when the battery electrode 121 is a negative electrode, the tab 1212 is a negative tab.

[0062] Among them, the battery electrode 121 can be a positive electrode or a negative electrode with a conventional structure, or a positive electrode or a negative electrode with a special structure. There is no specific limitation in this application and it can be selected according to the actual situation.

[0063] In one embodiment, the single battery 100 further includes: an electrode connector 140 and a pole 150 . The electrode connector 140 and the pole 150 are both disposed on the top cover 130 . The electrode connector 140 is electrically connected between the pole tab 1212 and the pole 150 .

[0064] The pole 150 may be made of conductive metal or other materials, but is not limited thereto. For example, the pole 150 may be made of metal copper or aluminum, but is not limited thereto.

[0065] The above-mentioned single cell 100 also includes an electrolyte and other functional components. The electrolyte can be a conventional electrolyte or a special electrolyte with additives added. The electrolyte is used to soak the winding core 120. The winding core 120 is a component in the single cell 100 where electrochemical reactions occur. The portion of the battery pole piece 121 with active substances constitutes the pole piece body 1211, and the portion of the battery pole piece 121 without active substances constitutes the pole ear 1212. During the charge and discharge process of the single cell 100, the active substance reacts with the electrolyte, and the pole ear 1212 is electrically connected to the pole column 150 to form a current loop, so that the single cell 100 can be used normally.

[0066] Specifically, the winding core 120 has a target side surface 124 and a folding reference surface 123 perpendicular to the thickness direction X, and the plurality of tabs 1212 are folded in a direction close to the folding reference surface 123 in the thickness direction X; in the thickness direction X, the distance between the folding reference surface 123 and the target side surface 124 is L1 mm, satisfying: (H-10) / 8≤L1≤(H-8) / 4; H mm is the maximum dimension of one of the winding cores 120 in the thickness direction X.

[0067] The target side surface 124 in the actual single battery 100 is specifically a plane on the winding core 120 that is perpendicular to the thickness direction X and close to the inner wall surface of the shell 110. The folding reference surface 123 in the actual single battery 100 is specifically a plane that is perpendicular to the thickness direction X and intersects with the welding position of the tab 1212. Exemplarily, the folding reference surface 123 is the plane where the tab 1212 closest to the center position of the winding core 120 of the single battery 100 is in a flattened state, but is not limited thereto. The maximum dimension of the winding core 120 in the thickness direction X is the thickness dimension corresponding to the winding core having the target side surface 124.

[0068] The distance L1 mm between the folded reference surface 123 and the target side surface 124 can be obtained by disassembling the actual single cell 100, measuring the dimensions between the folded reference surface 123 and the target side surface 124 on the winding core 120 in the single cell 100 multiple times using a measuring tool, and calculating the average value.

[0069] For example, the distance L1mm between the folded reference surface 123 and the target side surface 124 can be obtained by first obtaining the welding position of the tab 1212 on the winding core 120 after disassembling the actual single battery 100, that is, obtaining the actual position of the folded reference surface 123 in the single battery 100, and then using a measuring tool to measure the dimensions between the welding position of the tab 1212 and the target side surface 124 for multiple times and calculating the average value. The measuring tool can be any one of a ruler, a vernier caliper, or other dimension measuring instruments, but is not limited thereto.

[0070] The maximum dimension H mm of the winding core 120 in the thickness direction X can be obtained by disassembling the actual single battery 100, measuring the dimensions of the winding core 120 in the thickness direction X multiple times by using a measuring tool, and calculating the average value. For example, the maximum dimension H mm of the winding core 120 in the thickness direction X can be obtained by disassembling the actual single battery 100, measuring the dimensions of the two ends and the middle area of ​​the winding core 120 in the thickness direction X by using a measuring tool, and calculating the average value. The measuring tool can be any one of a ruler, a vernier caliper, or other dimension measuring instruments, but is not limited thereto.

[0071] The number of the winding cores 120 can be directly observed after the actual single battery 100 is disassembled.

[0072] It can be understood that in the present application, the distance L1mm between the folding reference surface 123 and the target side surface 124 is limited to satisfy (H-10) / 8≤L1≤(H-8) / 4, that is, the thickness and number of the winding core 120 are used to reasonably design the positions of the folding reference surfaces 123 of multiple pole tabs 1212 in different single cells, thereby avoiding the risk of pole tab redundancy or pole tab tearing when the multiple pole tabs 1212 are folded, ensuring the folding effect of the pole tabs 1212, thereby optimizing the electronic conduction path in the single cell 100, improving the power performance of the single cell 100, and ultimately improving the comprehensive performance of the single cell 100.

[0073] In one embodiment, referring to Figure 3 , the distance L1mm between the gathered reference surface 123 and the target side surface 124 in the thickness direction X also satisfies: 0≤L1≤18. That is, the distance L1mm between the gathered reference surface 123 and the target side surface 124 in the thickness direction X can be controlled within the range of 0~18mm. For example, L1mm can be one of 0mm, 2mm, 4mm, 6mm, 8mm, 10mm, 12mm, 14mm, 16mm or 18mm, or a range consisting of any two of them. The above specific values ​​of L1mm are given for example only, and any value within the range of 0~18mm is within the protection scope of this application. In the present application, the distance L1mm between the folding reference surface 123 and the target side surface 124 in the thickness direction X is controlled within the range of 0~18mm, so as to reasonably design the folding position of the pole tabs 1212 of different single cells 100, avoid the risk of pole tab redundancy or pole tab tearing when multiple pole tabs 1212 are folded, ensure the folding effect of the pole tabs 1212, thereby optimizing the electronic conduction path in the single cell 100, improving the power performance of the single cell 100, and finally improving the comprehensive performance of the single cell 100.

[0074] Reference Figure 3, the maximum dimension H mm of the core 120 in the thickness direction X satisfies: 10≤H≤80. That is, the maximum dimension H mm of the core 120 in the thickness direction X can be controlled within the range of 10mm~80mm. For example, H mm can be one of 10mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm or 80mm or a range consisting of any two of them. The above specific values ​​of H mm are given only as examples, and any value within the range of 10mm~80mm is within the protection scope of this application. This application controls the maximum dimension H mm of the core 120 in the thickness direction X within the range of 10mm~80mm to reasonably design the thickness of the core 120, thereby avoiding the risk of tab redundancy or tab tearing when multiple tabs 1212 are folded together, ensuring the folding effect of the tabs 1212, thereby optimizing the electronic conduction path in the single cell 100, improving the power performance of the single cell 100, and ultimately improving the comprehensive performance of the single cell 100.

[0075] In some embodiments, the maximum dimension H of the two winding cores in the thickness direction X may be the same.

[0076] In one embodiment, referring to Figure 2 , the number of winding layers of the winding core 120 is N1, and the number of tabs 1212 is N2, which satisfies: N1=N2. That is, the number of winding layers N1 of the winding core 120 and the number N2 of the tabs 1212 are equal, so as to further avoid the risk of tab redundancy or tab tearing when multiple tabs 1212 are folded together, and ensure the folding effect of the tabs 1212.

[0077] The number N1 of winding layers of the winding core 120 and the number N2 of the tabs 1212 can be directly observed after the actual single battery 100 is disassembled.

[0078] It should be understood that in an actual single cell 100 , since there is a tab-free area in the battery electrode 121 at the initial winding position or the end position of the winding, the number of winding layers N1 of the core 120 after the core 120 is wound is greater than the number N2 of the tabs 1212 .

[0079] In one embodiment, the winding core 120 is arranged into a first area 125 and a second area 126 with its center in the thickness direction X as the boundary. Specifically, the number of tabs 1212 in the first area 125 and the second area 126 may be the same, that is, the number of tabs 1212 located on both sides of the folding reference surface 123 in the thickness direction X may be the same, further avoiding the risk of tab redundancy or tab tearing when multiple tabs 1212 are folded, and ensuring the folding effect of the tabs 1212.

[0080] The difference in the number of the tabs 1212 in the first region 125 and the second region 126 may also be 1, that is, the number of the tabs 1212 in the first region 125 is one more than the number of the tabs 1212 in the second region 126, or the number of the tabs 1212 in the first region 125 is one less than the number of the tabs 1212 in the second region 126. That is, the multiple tabs 1212 may be symmetrically arranged at the tab 1212 at the center in the thickness direction X, further avoiding the risk of tab redundancy or tab tearing when the multiple tabs 1212 are gathered, and ensuring the gathering effect of the tabs 1212.

[0081] In the specific embodiment 2 of the present application,

[0082] Please refer to Figure 1 , Figure 2 and Figure 4 The present application also provides a single cell 100, wherein the single cell 100 has a thickness direction X, a length direction Y, and a height direction Z intersecting each other. Exemplarily, the single cell 100 has a thickness direction X, a length direction Y, and a height direction Z perpendicular to each other. Here, "perpendicular" refers to a state where the angle formed by a straight line and a straight line, a straight line and a plane, or a plane and a plane is 89° to 91°.

[0083] Specifically, the single battery 100 includes a housing 110 , a winding core 120 and a top cover 130 .

[0084] Specifically, four winding cores 120 are provided, and the four winding cores 120 are all accommodated in the shell 110. Each winding core 120 is distributed along the thickness direction X, and the winding core 120 is wound by the battery electrode 121 and the diaphragm 122. The top cover 130 is connected to the shell 110 and the top cover 130 covers the shell 110 to seal the shell 110.

[0085] Specifically, the battery electrode 121 includes: a electrode body 1211 and an electrode tab 1212 . A plurality of electrode tabs 1212 are provided, and the plurality of electrode tabs 1212 are connected to the electrode body 1211 .

[0086] The single cell 100 may be a secondary battery, which refers to a single cell that can be used continuously by activating the active material by charging after the single cell is discharged. Exemplarily, the single cell 100 may be a lithium ion battery, a sodium ion battery, a sodium lithium ion battery, a lithium metal battery, a sodium metal battery, a lithium sulfur battery, a magnesium ion battery, a nickel metal hydride battery or a nickel cadmium battery, but is not limited thereto.

[0087] The single battery 100 may be cylindrical, flat, long, or in other shapes.

[0088] In one embodiment, the single battery 100 further includes: an electrode connector 140 and a pole 150 . The electrode connector 140 and the pole 150 are both disposed on the top cover 130 . The electrode connector 140 is electrically connected between the pole tab 1212 and the pole 150 .

[0089] The above-mentioned single cell 100 also includes an electrolyte and other functional components. The electrolyte can be a conventional electrolyte or a special electrolyte with additives added. The electrolyte is used to soak the winding core 120. The winding core 120 is a component in the single cell 100 where electrochemical reactions occur. The portion of the battery pole piece 121 with active substances constitutes the pole piece body 1211, and the portion of the battery pole piece 121 without active substances constitutes the pole ear 1212. During the charge and discharge process of the single cell 100, the active substance reacts with the electrolyte, and the pole ear 1212 is electrically connected to the pole column 150 to form a current loop, so that the single cell 100 can be used normally.

[0090] Specifically, the winding core 120 has a target side surface 124 and a folding reference surface 123 perpendicular to the thickness direction X, and the plurality of tabs 1212 are folded in a direction close to the folding reference surface 123 in the thickness direction X. In the thickness direction X, the distance between the folding reference surface 123 and the target side surface 124 is L1 mm, satisfying: (4×H-10) / 16≤L1≤(4×H-8) / 4; H mm is the maximum dimension of one of the winding cores 120 in the thickness direction X.

[0091] The target side surface 124 in the actual single battery 100 is specifically a plane perpendicular to the thickness direction X and close to the inner wall surface of the shell 110 on the core 120 among the four cores 120 that is relatively close to the inner wall surface of the shell 110 in the thickness direction X.

[0092] The specific measurement methods of the distance L1 mm between the retracted reference surface 123 and the target side surface 124 , the maximum dimension H mm of the winding core 120 in the thickness direction X, and the number of the winding cores 120 are the same as those in the first specific embodiment, and reference may be made to the description in the first specific embodiment.

[0093] The maximum dimension of the winding core 120 in the thickness direction X is the thickness dimension corresponding to the winding core having the target side surface 124 .

[0094] It can be understood that in the present application, the distance L1mm between the folding reference surface 123 and the target side surface 124 is limited to satisfy (4×H-10) / 16≤L1≤(4×H-8) / 4, that is, the thickness and number of the winding core 120 are used to reasonably design the positions of the folding reference surfaces 123 of multiple pole tabs 1212 in different single cells, thereby avoiding the risk of pole tab redundancy or pole tab tearing when the multiple pole tabs 1212 are folded, ensuring the folding effect of the pole tabs 1212, thereby optimizing the electronic conduction path in the single cell 100, improving the power performance of the single cell 100, and ultimately improving the comprehensive performance of the single cell 100.

[0095] In one embodiment, referring to Figure 4 , the distance L1mm between the gathered reference surface 123 and the target side surface 124 in the thickness direction X also satisfies: 1.875≤L1≤78. That is, the distance L1mm between the gathered reference surface 123 and the target side surface 124 in the thickness direction X can be controlled within the range of 1.875mm~78mm. For example, L1mm can be one of 1.875mm, 10mm, 20mm, 30mm, 40mm, 50mm, 60mm, 70mm or 78mm, or a range consisting of any two of them. The above specific values ​​of L1mm are given for example only, and any value within the range of 0~18mm is within the protection scope of this application. The present application controls the distance L1mm between the folding reference surface 123 and the target side surface 124 in the thickness direction X within the range of 1.875mm~78mm, so as to reasonably design the folding position of the pole tabs 1212 of different single cells 100, avoid the risk of pole tab redundancy or pole tab tearing when multiple pole tabs 1212 are folded, ensure the folding effect of the pole tabs 1212, thereby optimizing the electronic conduction path in the single cell 100, improving the power performance of the single cell 100, and ultimately improving the comprehensive performance of the single cell 100.

[0096] The maximum dimension H mm of the winding core 120 in the thickness direction X satisfies: 10≤H≤80. That is, the maximum dimension H mm of the winding core 120 in the thickness direction X can be controlled within the range of 10 mm to 80 mm. For example, H mm can be one of 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm or 80 mm or a range consisting of any two of them. The above specific numerical values ​​of H mm are given only as examples, and any value within the range of 10 mm to 80 mm is within the protection scope of this application. This application controls the maximum dimension H mm of the winding core 120 in the thickness direction X within the range of 10 mm to 80 mm, so as to reasonably design the thickness of the winding core 120, thereby avoiding the risk of tab redundancy or tab tearing when multiple tabs 1212 are folded together, ensuring the folding effect of the tabs 1212, thereby optimizing the electronic conduction path in the single cell 100, improving the power performance of the single cell 100, and ultimately improving the comprehensive performance of the single cell 100.

[0097] In some embodiments, the maximum dimension H of the four winding cores in the thickness direction X may be the same.

[0098] At the same time, other technical features of the single cell 100 in the specific embodiment 2 of the present application are the same as those in the above-mentioned specific embodiment 1. In view of the fact that the corresponding features are described in detail in the above-mentioned specific embodiment 1, the specific embodiment 2 in the present application will not be described accordingly, and reference may be made to the description in the specific embodiment 1.

[0099] On the other hand, in an embodiment of the present application, the present application further provides a battery pack, including: a box body; and a single cell 100 as described in any of the above embodiments, wherein the single cell 100 is accommodated in the box body.

[0100] On the other hand, in an embodiment of the present application, the present application further provides an electric device, including: a battery pack as described above, the battery pack serving as a power supply for the electric device. The electric device described above may be, but is not limited to, mobile devices (such as mobile phones, laptops, etc.), electric vehicles (such as pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, electric scooters, electric golf carts, electric trucks, etc.), electric trains, ships and satellites, energy storage systems, etc.

[0101] In order to better understand the technical solution of the present application, a lithium-ion battery is taken as an example for further explanation below.

[0102] Example 1

[0103] This embodiment provides a method for preparing a lithium ion battery, and the specific process is as follows:

[0104] 1. Preparation of positive electrode

[0105] 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, and then NMP is added as a solvent for mixing, and stirred under vacuum 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 a 120°C oven for drying, and then rolled, slit, and cut into pieces to obtain a positive electrode sheet.

[0106] 2. Preparation of negative electrode sheet

[0107] 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 for mixing, and stirred under vacuum 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 a 110°C oven for drying, and then rolled, slit, and cut to obtain a negative electrode sheet.

[0108] 3. Preparation of electrolyte

[0109] Ethylene carbonate (EC), ethyl methyl carbonate (EMC) and diethyl carbonate (DEC) are mixed in a mass ratio of 3:4:3 to obtain an organic solvent, 1 mol / L of LiPF6 is added and mixed evenly, and then vinylene carbonate, vinyl sulfate and lithium difluorophosphate are added to prepare an electrolyte.

[0110] 4. Preparation of diaphragm

[0111] PP film is used as the separator.

[0112] 5. Preparation of lithium-ion batteries

[0113] The negative electrode sheet and the positive electrode sheet prepared by the above steps are dried and then prepared into a winding core together with the diaphragm by a winding machine. The positive electrode ears and the negative electrode ears are respectively gathered and welded to the end covers, and the welded winding core with the top cover is placed in an aluminum shell for packaging; the lithium-ion battery is obtained by injecting electrolyte and forming a constant capacity.

[0114] Among them, the maximum dimension H mm of the winding core 120 in the thickness direction X is 80 mm, the number of winding cores 120 is 2, (H-10) / 8 is 8.75, (H-8) / 4 is 18, and the distance L1mm between the folding reference surface 123 and the target side surface 124 in the thickness direction X is 18 mm.

[0115] Examples 2 to 5 all prepare lithium-ion batteries according to the method of Example 1, and the parameters of Examples 2 to 5 are shown in Table 1 below.

[0116] Example 6

[0117] A lithium ion battery was prepared according to the method of Example 1, except that:

[0118] The maximum dimension H mm of the winding core 120 in the thickness direction X is 80 mm, the number of winding cores 120 is 4, (4×H-10) / 16 is 19.375, (4×H-8) / 4 is 78, and the distance L1mm between the retracted reference surface 123 and the target side surface 124 in the thickness direction X is 78 mm.

[0119] Examples 7 to 10 all prepare lithium-ion batteries according to the method of Example 6, and the parameters of Examples 7 to 10 are shown in Table 2 below.

[0120] Comparative Example 1

[0121] A lithium ion battery was prepared according to the method of Example 1, except that:

[0122] The distance L1mm between the gathered reference surface 123 and the target side surface 124 in the thickness direction X is 6mm.

[0123] Comparative Example 2

[0124] A lithium ion battery was prepared according to the method of Example 1, except that:

[0125] The distance L1mm between the gathered reference surface 123 and the target side surface 124 in the thickness direction X is 20mm.

[0126] Comparative Example 3

[0127] A lithium ion battery was prepared according to the method of Example 1, except that:

[0128] The maximum dimension H mm of the winding core 120 in the thickness direction X is 8 mm, (H-10) / 8 is -0.25, (H-8) / 4 is 0, and the distance L1mm between the retracted reference surface 123 and the target side surface 124 in the thickness direction X is 0 mm.

[0129] Comparative Example 4

[0130] A lithium ion battery was prepared according to the method of Example 1, except that:

[0131] The maximum dimension H mm of the winding core 120 in the thickness direction X is 90 mm, (H-10) / 8 is 10, (H-8) / 4 is 20.5, and the distance L1mm between the retracted reference surface 123 and the target side surface 124 in the thickness direction X is 22 mm.

[0132] Comparative Example 5

[0133] A lithium ion battery was prepared according to the method of Example 6, except that:

[0134] The distance L1mm between the gathered reference surface 123 and the target side surface 124 in the thickness direction X is 10mm.

[0135] Comparative Example 6

[0136] A lithium ion battery was prepared according to the method of Example 6, except that:

[0137] The distance L1mm between the gathered reference surface 123 and the target side surface 124 in the thickness direction X is 80mm.

[0138] Comparative Example 7

[0139] A lithium ion battery was prepared according to the method of Example 6, except that:

[0140] The maximum dimension H mm of the winding core 120 in the thickness direction X is 8 mm, (4×H-10) / 16 is 1.375, (4×H-8) / 4 is 6, and the distance L1mm between the retracted reference surface 123 and the target side surface 124 in the thickness direction X is 0.5 mm.

[0141] Comparative Example 8

[0142] A lithium ion battery was prepared according to the method of Example 6, except that:

[0143] The maximum dimension H mm of the winding core 120 in the thickness direction X is 90 mm, (4×H-10) / 16 is 21.875, (4×H-8) / 4 is 88, and the distance L1mm between the retracted reference surface 123 and the target side surface 124 in the thickness direction X is 90 mm.

[0144] The batteries prepared in the above embodiments and comparative examples were subjected to performance tests, and the specific test items were tested as follows:

[0145] 1. Test method for Hi-Pot resistance of lithium-ion battery:

[0146] At 25°C, the lithium-ion battery is placed in a Hi-Pot tester, and the Hi-Pot tester is controlled to apply a DC voltage of 1000V to the lithium-ion battery to obtain a corresponding current value, and the Hi-Pot resistance of the shell is calculated.

[0147] 2. Test method for whether the lithium-ion battery tabs are redundant:

[0148] After the negative electrode sheet, the positive electrode sheet and the separator are used together to prepare the winding core by a winding machine, the positive electrode ear and the negative electrode ear are respectively gathered along the corresponding gathering positions to observe whether the positive electrode ear or the negative electrode ear is intercalated to determine whether the positive electrode ear or the negative electrode ear is redundant. If the positive electrode ear or the negative electrode ear is intercalated, the lithium-ion battery electrode ear is redundant, and vice versa, if the positive electrode ear or the negative electrode ear is not intercalated, the lithium-ion battery electrode ear is not redundant.

[0149] 3. Test method for whether the lithium-ion battery tab is torn:

[0150] After the negative electrode sheet, the positive electrode sheet and the separator are used together to prepare the winding core by a winding machine, the positive electrode ear and the negative electrode ear are respectively folded along the corresponding folding positions to observe whether the positive electrode ear or the negative electrode ear is torn.

[0151] 4. Test method for power performance of lithium-ion batteries

[0152] At 25°C, the lithium-ion battery was left to stand for 30 minutes, then discharged at a constant current of 1C, left to stand for 10 minutes, then charged at a constant current and constant voltage of 1C, left to stand for 30 minutes, and then discharged at a constant current of 3C to test the maximum temperature rise on the battery surface during the discharge process. The lower the temperature rise, the better the power performance of the battery.

[0153] The relevant parameters and test results in the above embodiments and comparative examples are recorded in Table 1 and Table 2.

[0154] Table 1 Parameters and test results of Examples 1 to 5 and Comparative Examples 1 to 4

[0155]

[0156] It can be seen from the data in Table 1 that: in Comparative Examples 1 to 4, the specific parameters of the lithium-ion batteries exceed the parameter range in the present application, and the lithium-ion batteries do not exhibit corresponding performance and do not meet the requirements; while in Examples 1 to 5, since the distance L1mm between the folding reference surface 123 and the target side surface 124 is limited to satisfy: (H-10) / 8≤L1≤(H-8) / 4, compared with Comparative Examples 1~4, they have excellent tab folding effect and power performance.

[0157] It can be seen that the present application satisfies the following conditions by limiting the distance L1mm between the folding reference surface 123 and the target side surface 124 to: (H-10) / 8≤L1≤(H-8) / 4, the distance L1mm between the folding reference surface 123 and the target side surface 124 in the thickness direction X to be within the range of 0~18mm, and the maximum dimension H mm of the winding core 120 in the thickness direction X to be within the range of 10mm~80mm, so as to reasonably design the positions of the folding reference surfaces 123 of multiple pole tabs 1212 in different single cells by utilizing the thickness and number of the winding core 120, thereby avoiding the risk of pole tab redundancy or pole tab tearing when multiple pole tabs 1212 are folded, ensuring the folding effect of the pole tabs 1212, thereby optimizing the electron conduction path in the single cell 100 and improving the power performance of the single cell 100.

[0158] Table 2 Parameters and test results of Examples 6 to 10 and Comparative Examples 5 to 8

[0159]

[0160] It can be seen from the data in Table 2 that: in Comparative Examples 5 to 8, the specific parameters of the lithium-ion batteries exceed the parameter range in the present application, and the lithium-ion batteries do not exhibit corresponding performance and do not meet the requirements; while in Examples 6 to 10, since the distance L1mm between the folding reference surface 123 and the target side surface 124 is limited to satisfy (4×H-10) / 16≤L1≤(4×H-8) / 4, they have excellent tab folding effect and power performance compared to Comparative Examples 5~8.

[0161] It can be seen that the present application satisfies the following conditions by limiting the distance L1mm between the folding reference surface 123 and the target side surface 124 to: (4×H-10) / 16≤L1≤(4×H-8) / 4, the distance L1mm between the folding reference surface 123 and the target side surface 124 in the thickness direction X to be within the range of 1.875mm~78mm, and the maximum dimension H mm of the winding core 120 in the thickness direction X to be within the range of 10mm~80mm, so as to reasonably design the positions of the folding reference surfaces 123 of multiple pole tabs 1212 in different single cells by utilizing the thickness and number of the winding core 120, thereby avoiding the risk of pole tab redundancy or pole tab tearing when multiple pole tabs 1212 are folded, ensuring the folding effect of the pole tabs 1212, thereby optimizing the electron conduction path in the single cell 100 and improving the power performance of the single cell 100.

[0162] The introduction provided in the above steps is only used to help understand the method, structure and core idea of ​​the present application. For ordinary technicians in this technical field, 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 claims of the present application.

Claims

1. A single cell battery having a thickness direction, characterized in that: include: case; as well as Two winding cores are contained in the shell, each of the winding cores is distributed along the thickness direction, and the winding cores are wound by winding the battery pole piece and the diaphragm; The battery pole piece comprises: a pole piece body; and A plurality of pole ears connected to the pole piece body; The winding core has a target side surface and a retraction reference surface perpendicular to the thickness direction, the target side surface is a plane on the winding core perpendicular to the thickness direction and close to the inner wall surface of the shell, and the plurality of tabs are retracted in a direction close to the retraction reference surface in the thickness direction; In the thickness direction, the distance between the gathered reference surface and the target side surface is L1 mm, satisfying: (H-10) / 8≤L1≤(H-8) / 4, 0≤L1≤18, 10≤H≤80; H mm is the maximum dimension of one of the winding cores in the thickness direction.

2. The single cell according to claim 1, characterized in that: The number of winding layers of the winding core is N1, and the number of the pole ears is N2, satisfying: N1= N2.

3. The single cell according to claim 2, characterized in that: The winding core is arranged into a first area and a second area with its center in the thickness direction as a boundary; The number of the tabs in the first region is the same as that in the second region; or, The difference in number of the tabs in the first region and the second region is 1.

4. The single cell according to claim 1, characterized in that: The battery electrode is either a positive electrode or a negative electrode.

5. The single cell according to claim 1, characterized in that: It also includes: a top cover, an electrode connector and a pole; The top cover is covered on the shell, the electrode connector and the pole are both arranged on the top cover, and the electrode connector is electrically connected between the pole ear and the pole.

6. A single cell battery having a thickness direction, characterized in that: include: case; as well as Four winding cores are contained in the shell, each of the winding cores is distributed along the thickness direction, and the winding cores are wound by winding the battery pole piece and the diaphragm; The battery pole piece comprises: a pole piece body; and A plurality of pole ears connected to the pole piece body; The winding core has a target side surface perpendicular to the thickness direction and a retracted reference surface, the target side surface is a plane perpendicular to the thickness direction and close to the inner wall surface of the shell on the winding core relatively close to the inner wall surface of the shell in the thickness direction among the four winding cores, and the plurality of tabs are retracted in a direction close to the retracted reference surface in the thickness direction; In the thickness direction, the distance between the gathered reference surface and the target side surface is L1 mm, satisfying: (4×H-10) / 16≤L1≤(4×H-8) / 4, 1.875≤L1≤78, 10≤H≤80; H mm is the maximum dimension of one of the winding cores in the thickness direction.

7. A battery pack, characterized in that: include: Box; as well as The single cell battery according to any one of claims 1 to 6, wherein the single cell battery is housed in the box.

8. An electrical device, characterized in that: include: The battery pack as claimed in claim 7, wherein the battery pack serves as a power supply for the electrical device.

Images