Battery cell, battery device, and electric device

Abstract

The application relates to a battery monomer, a battery device and an electric equipment. The battery monomer comprises a shell and an electrode assembly comprising a positive electrode sheet, a negative electrode sheet and a diaphragm. At least one surface of the diaphragm is provided with a first region and a second region. In the winding direction of the electrode assembly, the first region is located on at least one side of the second region. The first region is coated with at least one row of first dot groups arranged in the winding direction. The second region is coated with at least one row of second dot groups arranged in the winding direction. In the first row of first dot groups located at the edge of the diaphragm in the first region, the interval between two adjacent first dots is smaller than the interval between two adjacent second dots in any row of second dot groups. A coating line is connected between adjacent first dots, and / or between adjacent second dots, and / or between adjacent first dots and second dots. The application can improve the bonding firmness of the diaphragm edge position and improve the bonding strength of the diaphragm.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a battery cell, battery device, and electrical equipment. Background Technology

[0002] Depending on the manufacturing process, battery cells can be divided into wound and stacked types. For wound battery cells, the positive electrode, separator, and negative electrode are stacked in sequence, then wound and shaped to form the electrode assembly. However, the edges of the electrode assembly are prone to openings due to weak adhesion, affecting the performance of the battery cell. Utility Model Content

[0003] Therefore, it is necessary to provide a battery cell, battery device, and electrical equipment to address the problem that the edges of electrode components are prone to opening due to poor adhesion.

[0004] In a first aspect, this application provides a battery cell, including a housing and an electrode assembly. The electrode assembly is disposed inside the housing and includes a positive electrode, a negative electrode, and a separator. The positive electrode, separator, and negative electrode are sequentially stacked and wound to form the electrode assembly. The separator has a first region and a second region on at least one surface. In the winding direction of the electrode assembly, the first region is located on at least one side of the second region. The first region is coated with at least one row of first coating dots arranged along the winding direction of the electrode assembly, and the second region is coated with at least one row of second coating dots arranged along the winding direction. In the first row of first coating dots located at the edge of the separator in the first region, the distance between two adjacent first coating dots is less than the distance between two adjacent second coating dots in any row of second coating dots. Coating lines connect adjacent first coating dots, and / or adjacent second coating dots, and / or adjacent first coating dots and second coating dots.

[0005] By setting first coating points and second coating points in the first and second regions respectively, and making the distribution of the first coating points at the edge of the diaphragm more dense while the distribution of the second coating points is relatively sparse, the adhesion strength at the edge of the diaphragm can be improved, and the probability of openings appearing in the electrode assembly after winding can be reduced.

[0006] Furthermore, by setting coating lines, the connection between the first coating point and the second coating point can be achieved, and the coating area on the diaphragm can be further increased, effectively improving the bonding strength of the diaphragm.

[0007] In some embodiments, in each of the first groups of first dots in the first region other than the first row of first dots, the distance between two adjacent first dots is less than the distance between two adjacent second dots in any row of second dots.

[0008] With the above structure, the spacing between two adjacent first coating dots in each row of the first coating dot group is smaller than the spacing between two adjacent second coating dots in each row of the second coating dot group, making the first coating dots at the edge of the diaphragm more dense and further improving the bonding strength at the edge of the diaphragm.

[0009] In some embodiments, in the same row of first coating dots in the first region, the distance between two adjacent first coating dots is a first distance; the distance between two adjacent rows of first coating dots in the first region is a second distance; wherein, the range of the first distance is 100μm to 200μm; and / or, the range of the second distance is 100μm to 200μm.

[0010] The above structure can effectively improve the bonding strength at the edge of the diaphragm, reduce the probability of burrs inserting into the diaphragm, and also minimize the overall weight of the diaphragm.

[0011] In some embodiments, in the same row of second coating dots in the second region, the spacing between two adjacent second coating dots is a third spacing; the spacing between two adjacent rows of second coating dots in the second region is a fourth spacing; wherein the third spacing ranges from 250μm to 500μm; and / or, the fourth spacing ranges from 250μm to 500μm.

[0012] The above structure can better balance the bonding strength between the separator and the positive or negative electrode plate, as well as the overall weight of the separator.

[0013] In some embodiments, the sum of the areas of each first coating point accounts for 20% to 60% of the total area of ​​all first coating points and all second coating points.

[0014] Setting the sum of the areas of each first coating point to the range mentioned above not only improves the bonding strength at the edge of the diaphragm, thereby reducing the probability of openings in the electrode assembly, but also effectively reduces the overall weight of the diaphragm.

[0015] In some embodiments, the sum of the areas of all first coating points and all second coating points accounts for 8% to 23% of the total area of ​​the first region and the second region.

[0016] Setting the sum of the areas of all first coating points and all second coating points to the range mentioned above allows for a better balance between the overall adhesive strength and overall weight of the diaphragm.

[0017] In some embodiments, the area of ​​each second coating point is larger than the area of ​​each first coating point. With the above structure, in addition to achieving strong adhesion at the edge of the separator, the second coating points can also improve the liquid retention capacity of the electrode assembly and enhance the performance of the battery cell.

[0018] In some embodiments, each first coating dot is configured as a circular coating dot, and the diameter of each first coating dot ranges from 50 μm to 100 μm.

[0019] Setting the diameter of each first coating point to the range described above can better improve the adhesion strength at the edge of the diaphragm, thereby reducing the probability of openings appearing at the edge of the electrode assembly.

[0020] In some embodiments, the height of each first coating dot protruding from the membrane surface is 5 μm to 10 μm. Setting the height of each first coating dot protruding from the membrane surface within the above range allows each first coating dot to better adhere the membrane to the positive or negative electrode, improving the adhesion strength at the membrane edge.

[0021] In some embodiments, each second coating point is configured as a circular coating point, and the diameter of each second coating point ranges from 100 μm to 300 μm.

[0022] Setting the diameter of each second coating point to the range mentioned above allows for a better balance between the adhesive strength of the diaphragm and the overall weight of the diaphragm.

[0023] In some embodiments, the height of each second coating point protruding from the diaphragm surface is 10 μm to 15 μm.

[0024] Setting the height of each second coating point protruding from the separator surface to the range mentioned above can provide more space for expansion and deformation of the large surface area of ​​the battery cell corresponding to the second region, thereby improving the performance of the battery cell.

[0025] Secondly, this application also provides a battery device, including the battery cell as described above.

[0026] Thirdly, this application also provides an electrical device, including the battery device described above.

[0027] In the aforementioned battery cell, battery device, and electrical equipment, the winding direction of the electrode assembly, which is the width direction of the positive electrode sheet, separator, and negative electrode sheet before winding, divides the separator into a first region and a second region. The first region is located on at least one side of the second region, that is, the first region is located near the edge, while the second region is located in the middle. Furthermore, the first region is located in the first row of first coating dots at the edge of the separator, and the distance between two adjacent first coating dots is smaller than the distance between two adjacent second coating dots in any row of second coating dots in the second region. This makes the distribution of first coating dots at the edge of the separator more dense, while the distribution of second coating dots is relatively sparse. This can improve the adhesion strength at the edge of the separator and reduce the probability of openings in the electrode assembly after winding. In addition, the coating lines between the first and second coating dots can further increase the coating area on the separator, effectively improving the adhesion strength of the separator. Attached Figure Description

[0028] Figure 1 This is a structural schematic diagram of a vehicle according to one or more embodiments.

[0029] Figure 2 This is an exploded structural diagram of a battery device according to one or more embodiments.

[0030] Figure 3 This is an exploded structural diagram of a battery cell according to one or more embodiments.

[0031] Figure 4 This is a schematic diagram of the structure of the separator in a battery cell according to one or more embodiments.

[0032] Figure 5 This is a schematic diagram of the structure of the separator in a battery cell according to one or more embodiments.

[0033] Figure 6 This is a schematic diagram of the structure of the separator in a battery cell according to one or more embodiments.

[0034] Explanation of reference numerals in the attached drawings: 1000, vehicle; 100, battery device; 200, controller; 300, motor; 10, housing; 20, battery cell; 11, first part; 12, second part; 21, top cover; 22, shell body; 23, electrode assembly; 24, separator; 241, first region; 242, second region; 243, first coating spot; 244, second coating spot; 245, coating line; a, roll direction. Detailed Implementation

[0035] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0036] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0037] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0039] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0041] Currently, judging from market trends, the application of battery devices is becoming increasingly widespread. Battery devices are not only used in energy storage power systems such as hydropower, thermal power, wind power, and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, and electric cars, as well as other fields. With the continuous expansion of the application areas of battery devices, the market demand is also constantly increasing.

[0042] A battery cell is the smallest unit that makes up a battery device. A battery cell typically includes a housing and an electrode assembly. The housing has an internal cavity in which the electrode assembly can be placed, and the housing protects the electrode assembly.

[0043] Furthermore, depending on the manufacturing method of the battery cell, it can be divided into wound type and stacked type. For wound type battery cells, the positive electrode sheet, separator and negative electrode sheet are first stacked in sequence, then the stacked positive electrode sheet, separator and negative electrode sheet are wound, and then shaped to form an electrode assembly.

[0044] However, the increasing demands for energy density in battery cells have led to a rise in the number of layers in the electrode assembly, including the positive electrode, separator, and negative electrode. This, in turn, increases the likelihood of openings at the edges of the electrode assembly due to weak adhesion, negatively impacting the overall performance of the battery cell.

[0045] Based on the above considerations, to address the issue of openings easily occurring at the edges of the electrode assembly due to weak adhesion, one or more embodiments of this application propose a battery cell where, along the winding direction of the electrode assembly, the separator is divided into a first region and a second region. The first region is located on at least one side of the second region; that is, the first region is positioned near the edge, while the second region is located in the middle. Furthermore, the first region is located in the first row of first coating dots at the edge of the separator, and the spacing between two adjacent first coating dots is smaller than the spacing between two adjacent second coating dots in any row of second coating dots in the second region. This results in a denser distribution of first coating dots at the edge of the separator, while the distribution of second coating dots is relatively sparse. This improves the adhesion strength at the edge of the separator and reduces the probability of openings in the electrode assembly after winding.

[0046] It should be noted that the battery device mentioned in the embodiments of this application may include one or more battery cell assemblies for providing voltage and capacity. A battery cell assembly may include multiple battery cells, which are connected in series, parallel, or mixed connections via a busbar.

[0047] In some embodiments, a battery cell assembly is typically formed by arranging multiple battery cells. As an example, a battery cell assembly can be a battery module, which is formed by arranging and fixing multiple battery cells together to form a single module. As an example, a battery module can be formed by bundling multiple battery cells together with cable ties.

[0048] In some embodiments, the battery device may be a battery pack, which includes a housing and one or more individual battery cell assemblies housed within the housing.

[0049] As an example, the battery cell assembly can be a battery module, and the battery cell assembly can be housed in the housing by fixing the battery module in the housing.

[0050] As an example, battery cell assemblies can also be housed in a housing by directly fixing multiple battery cells to the housing.

[0051] The battery devices disclosed in this application can be used, but are not limited to, in electrical equipment such as vehicles, ships, or aircraft.

[0052] This application provides an electrical device that uses a battery as a power source. The electrical device can be, but is not limited to, mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, spacecraft, etc. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys, etc. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft, etc.

[0053] For ease of explanation, the following embodiments will be described using a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0054] Please refer to Figure 1The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, etc. A battery device 100 is installed inside the vehicle 1000, and the battery device 100 can be located at the bottom, front, or rear of the vehicle 1000. The battery device 100 can be used to power the vehicle 1000; for example, the battery device 100 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller 200 and a motor 300. The controller 200 is used to control the battery device 100 to supply power to the motor 300, for example, to meet the power needs of the vehicle 1000 during starting, navigation, and driving.

[0055] In some embodiments of this application, the battery device 100 can not only serve as the operating power source for the vehicle 1000, but also as the driving power source for the vehicle 1000, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle 1000.

[0056] Please refer to Figure 2 The battery device 100 includes a housing 10 and a battery cell 20, with the battery cell 20 housed within the housing 10. The housing 10 provides a space for the battery cell 20 and can have various structures. In some embodiments, the housing 10 may include a first portion 11 and a second portion 12, which overlap each other, collectively defining a space for accommodating the battery cell 20. The second portion 12 may be a hollow structure with one open end, and the first portion 11 may be a plate-like structure, covering the open side of the second portion 12 so that the first portion 11 and the second portion 12 together define the space. Alternatively, both the first portion 11 and the second portion 12 may be hollow structures with one open side, with the open side of the first portion 11 covering the open side of the second portion 12. Of course, the housing 10 formed by the first portion 11 and the second portion 12 can have various shapes, such as a cylinder, a cuboid, etc.

[0057] In the battery device 100, there can be multiple battery cells 20, which can be connected in series, parallel, or in a mixed configuration. A mixed configuration means that multiple battery cells 20 are connected in both series and parallel connections. Multiple battery cells 20 can be directly connected in series, parallel, or in a mixed configuration, and then the entire assembly of the multiple battery cells 20 is housed within the housing 10. Alternatively, the battery device 100 can also consist of multiple battery cells 20 first connected in series, parallel, or in a mixed configuration to form battery modules, and then these battery modules are connected in series, parallel, or in a mixed configuration to form a whole, which is also housed within the housing 10. The battery device 100 may also include other structures; for example, it may include a busbar component for electrical connection between the multiple battery cells 20.

[0058] Each battery cell 20 can be a secondary battery or a primary battery; it can also be a lithium-sulfur battery, a sodium-ion battery, or a magnesium-ion battery, but is not limited to these. The battery cell 20 can be cylindrical, flat, cuboid, or other shapes.

[0059] Please refer to Figure 3 A battery cell 20 refers to the smallest unit that makes up a battery. A battery cell 20 typically includes a casing, an electrode assembly 23, and other functional components. The casing includes a top cover 21 and a casing body 22. The top cover 21 is a component that closes onto the opening of the casing body 22 to isolate the internal environment of the battery cell 20 from the external environment. The shape of the top cover 21 may be adapted to the shape of the casing body 22 to fit it. Functional components such as electrode terminals may be provided on the top cover 21; these electrode terminals are also called terminals. The electrode terminals can be used to electrically connect to the electrode assembly 23 for outputting or inputting electrical energy into the battery cell 20. In some embodiments, the top cover 21 may also be provided with a pressure relief mechanism for releasing internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold. In some embodiments, an insulating member may be provided inside the top cover 21. This insulating member can be used to isolate the electrical connection components within the casing body 22 from the top cover 21 to reduce the risk of short circuits. Exemplarily, the insulating member may be made of plastic, rubber, etc.

[0060] The casing body 22 is a component used to cooperate with the top cover 21 to form the internal environment of the battery cell 20. This internal environment can accommodate the electrode assembly 23, electrolyte, and other components. The casing body 22 and the top cover 21 can be independent components. An opening can be provided on the casing body 22, and the top cover 21 can close the opening to form the internal environment of the battery cell 20. Alternatively, the top cover 21 and the casing body 22 can be integrated. Specifically, the top cover 21 and the casing body 22 can form a common connecting surface before other components are inserted into the casing. When it is necessary to encapsulate the interior of the casing body 22, the top cover 21 closes the casing body 22. The casing body 22 can have various shapes and sizes, such as cuboid, cylindrical, or hexagonal prism. Specifically, the shape of the casing body 22 can be determined according to the specific shape and size of the electrode assembly 23.

[0061] Electrode assembly 23 is the component in the battery cell 20 where electrochemical reactions occur. The casing 22 may contain one or more electrode assemblies 23. Electrode assembly 23 mainly consists of a positive electrode, a separator, and a negative electrode. Specifically, positive and negative active materials are coated onto the current collector to form the positive and negative electrode, respectively. The positive and negative electrode are wound or stacked, with the separator positioned between them, thus forming electrode assembly 23. The portions of the positive and negative electrode with active material constitute the main body of electrode assembly 23, while the portions without active material each constitute a tab. The positive and negative tabs may be located together at one end of the main body or at opposite ends. During charging and discharging, the positive and negative active materials react with the electrolyte, and the tabs connect to the electrode terminals to form a current loop.

[0062] Please refer to the following: Figure 3 and Figure 4 One embodiment of this application provides a battery cell 20, including a housing and an electrode assembly 23. The electrode assembly 23 is disposed inside the housing and includes a positive electrode (not shown), a negative electrode (not shown), and a separator 24. The positive electrode, separator 24, and negative electrode are sequentially stacked and wound to form the electrode assembly 23. At least one surface of the separator 24 has a first region 241 and a second region 242. In the winding direction a of the electrode assembly 23, the first region 241 is located on at least one side of the second region 242. The first region 241 is coated with at least one row of first coating dots arranged along the winding direction (not shown) of the electrode assembly 23, and the second region 242 is coated with at least one row of second coating dots arranged along the winding direction. In the first row of first coating dots located at the edge of the separator 24 within the first region 241, the spacing between two adjacent first coating dots 243 is smaller than the spacing between two adjacent second coating dots 244.

[0063] It should be noted that the shell refers to the structure that encloses and forms a cavity for accommodating the electrode assembly 23 and provides protection for the electrode assembly 23. The electrode assembly 23 is the component in the battery cell 20 where the electrochemical reaction actually takes place. The electrode assembly 23 includes a positive electrode, a negative electrode, and a separator 24. The positive electrode refers to the structure formed by coating a positive electrode active material onto the current collector, and the negative electrode refers to the structure formed by coating a negative electrode active material onto the current collector.

[0064] First, the positive electrode, separator 24, and negative electrode are stacked sequentially. The separator 24 is placed between each pair of adjacent positive and negative electrode layers to provide isolation and insulation. The stacked positive electrode, separator 24, and negative electrode are then wound and pressed and shaped to form the electrode assembly 23.

[0065] Specifically, the separator 24 has two opposing surfaces along its thickness direction, with a first region 241 and a second region 242 formed on at least one surface. The winding direction 'a' of the electrode assembly 23 refers to the height direction of the battery cell 20, which is the width direction of the stacked positive electrode, separator 24, and negative electrode before winding. The first region 241 is located on at least one side of the second region 242 along the winding direction 'a' of the electrode assembly 23; that is, before winding, the first region 241 is located on at least one side of the second region 242 along the width direction of the separator 24. Thus, the first region 241 is located at the edge along the width direction of the separator 24, corresponding to the tabs of the stacked positive or negative electrode. The second region 242 is located in the middle along the width direction of the separator 24, corresponding to the active material region of the stacked positive or negative electrode.

[0066] To ensure stable adhesion between the stacked positive electrode, separator 24, and negative electrode, adhesive is typically applied to the surface of the separator 24 to enhance bonding stability between the separator 24 and the positive or negative electrode. This dot-coating method achieves both adhesion stability and weight reduction of the separator 24, resulting in a lighter design.

[0067] For the wound battery cell 20, since the electrode assembly 23 is formed by winding the stacked positive electrode sheet, separator 24 and negative electrode sheet, even after pressing and shaping, the edges of the positive electrode sheet, separator 24 and negative electrode sheet are still prone to opening due to poor adhesion.

[0068] Based on this, at least one row of first coating dot groups is coated in the first region 241, and each row of first coating dot groups includes a plurality of first coating dots 243 arranged at intervals along the winding direction. Wherein, when the first region 241 is coated with two or more rows of first coating dot groups, each row of first coating dot groups is arranged at intervals along the roll direction a.

[0069] Meanwhile, at least one row of second coating dots is applied to the second region 242, and each row of second coating dots includes a plurality of second coating dots 244 spaced apart along the winding direction. When the second region 242 is coated with two or more rows of second coating dots, the rows of second coating dots are spaced apart along the roll direction a.

[0070] The first coating point 243 and the second coating point 244 enable bonding between the separator 24 and the positive or negative electrode. Further, the first row of first coating points located at the edge of the separator 24 within the first region 241 refers to the row of first coating points closest to the edge of the separator 24 along the spool direction a of the electrode assembly 23. This first row of first coating points can be either the row closest to the upper edge of the separator 24 or the row closest to the lower edge of the separator 24.

[0071] Specifically, the spacing between two adjacent first coating dots 243 in the first row of the first coating dot group is smaller than the spacing between two adjacent second coating dots 244 in any row of the second coating dot group. In other words, the distribution of the first coating dots 243 in the first row of the first coating dot group is relatively dense, while the distribution of the second coating dots 244 in the second region 242 is relatively dispersed. This denser distribution of the first coating dots 243 improves the adhesion strength at the edge of the diaphragm 24 and reduces the probability of edge opening.

[0072] In addition, it should be noted that the edges of the positive and negative electrode plates are not coated with active material. The exposed current collector is cut to form tabs. During the cutting process, burrs or wires are easily generated. During the winding or other processes, the burrs or wires can easily pierce or insert into the separator 24, causing the positive and negative electrodes to come into direct contact and causing an internal short circuit.

[0073] The dense distribution of the first coating dots 243 in the first row of the first coating dot group located at the edge of the diaphragm 24 can not only improve the bonding strength at the edge of the diaphragm 24, but also reduce the probability of burr insertion and reduce the risk of short circuit.

[0074] Thus, by setting the first coating point 243 and the second coating point 244 in the first region 241 and the second region 242 respectively, and making the distribution of the first coating point 243 at the edge of the diaphragm 24 more dense, while the distribution of the second coating point 244 is relatively sparse, the bonding firmness at the edge of the diaphragm 24 can be improved, and the probability of the electrode assembly 23 having an opening after winding can be reduced.

[0075] In some embodiments, in each of the first groups of first coating dots in the first region 241 other than the first row of first coating dots, the distance between two adjacent first coating dots 243 is less than the distance between two adjacent second coating dots 244 in any row of second coating dots.

[0076] Specifically, the first coating dot group can be set in multiple rows, and each row of the first coating dot group is arranged at intervals along the roll direction a within the first region 241. The spacing between two adjacent first coating dots 243 in each row of the first coating dot group is smaller than the spacing between two adjacent second coating dots 244 in any row of the second coating dot group. In this way, the distribution of the first coating dots 243 in the first region 241 is more dense, which can better improve the bonding strength of the edge of the diaphragm 24.

[0077] Thus, through the above structure, the spacing between two adjacent first coating dots 243 in each row of the first coating dot group is smaller than the spacing between two adjacent second coating dots 244 in each row of the second coating dot group, making the first coating dots 243 at the edge of the diaphragm 24 more dense and further improving the bonding strength at the edge of the diaphragm 24.

[0078] In some embodiments, within the first region 241, the distance between two adjacent first coating dots 243 in the same row of first coating dot groups is a first distance D1; the distance between two adjacent rows of first coating dot groups in the first region 241 is a second distance D2. The first distance D1 ranges from 100 μm to 200 μm, and / or the second distance D2 ranges from 100 μm to 200 μm.

[0079] As a specific embodiment, the first spacing D1 can be set to 100μm, 120μm, 140μm, 160μm, 180μm, or 200μm, and the second spacing D2 can be set to 100μm, 120μm, 140μm, 160μm, 180μm, or 200μm.

[0080] It should be noted that the first spacing between two adjacent first coating dots 243 in each row of the first coating dot group can be constant or variable. That is to say, the first coating dots 243 in each row can be arranged at uniform intervals or at non-uniform intervals.

[0081] Similarly, the second spacing between two adjacent rows of first dot groups within the first region 241 can be constant or variable. That is, the second spacing between different rows of first dot groups can be the same or different.

[0082] Specifically, the size of the first gap and the second gap will affect the bonding strength at the edge of the diaphragm 24 and the probability of burrs being inserted into the diaphragm 24, as well as the overall weight of the diaphragm 24.

[0083] Thus, by setting the first and second spacings to the ranges described above, the bonding strength at the edge of the diaphragm 24 can be effectively improved, the probability of burrs being inserted into the diaphragm 24 can be reduced, and the overall weight of the diaphragm 24 can be reduced as much as possible.

[0084] In some embodiments, within the second region 242, the spacing between two adjacent second coating dots 244 in the same row of second coating dot groups is a third spacing D3; the spacing between two adjacent rows of second coating dot groups in the second region 242 is a fourth spacing D4. The third spacing D3 ranges from 250 μm to 500 μm; and / or, the fourth spacing D4 ranges from 250 μm to 500 μm.

[0085] As a specific embodiment, the third spacing D3 can be set to 250μm, 300μm, 350μm, 400μm, 450μm, or 500μm, and the fourth spacing D4 can be set to 250μm, 300μm, 350μm, 400μm, 450μm, or 500μm.

[0086] It should be noted that the third spacing D3 between two adjacent second coating dots 244 in each row of the second coating dot group can be constant or variable. That is to say, the second coating dots 244 in each row can be arranged at uniform intervals or at non-uniform intervals.

[0087] Similarly, the fourth spacing D4 between two adjacent rows of second dot groups within the second region 242 can be constant or variable. That is, the fourth spacing D4 between different rows of second dot groups can be the same or different.

[0088] Specifically, the size of the third and fourth spacings not only affects the adhesion strength between the separator 24 and the positive or negative electrode, but also affects the overall weight of the separator 24.

[0089] Therefore, setting the third and fourth spacings to the ranges described above can better balance the bonding strength between the separator 24 and the positive or negative electrode sheet, as well as the overall weight of the separator 24.

[0090] In some embodiments, the sum of the areas of each first coating point 243 accounts for 20% to 60% of the total area of ​​all first coating points 243 and all second coating points 244.

[0091] Specifically, all the first coating dots 243 and all the second coating dots 244 together constitute the coating area. The ratio between the sum of the areas of each first coating dot 243 and the total area of ​​the coating area will not only affect the bonding strength at the edge of the diaphragm 24, thus affecting the probability of the electrode assembly 23 forming an opening, but also affect the overall weight of the diaphragm 24.

[0092] Therefore, by setting the sum of the areas of each first coating point 243 to the above range, it is possible not only to improve the bonding strength at the edge of the diaphragm 24, thereby reducing the probability of the electrode assembly 23 having an opening, but also to effectively reduce the overall weight of the diaphragm 24.

[0093] In some embodiments, the sum of the areas of all first coating points 243 and all second coating points 244 accounts for 8% to 23% of the total area of ​​the first region 241 and the second region 242.

[0094] Specifically, the sum of the areas of all first coating points 243 and all second coating points 244 is the area of ​​the coating area. The relationship between the area of ​​the coating area and the total area of ​​the first region 241 and the second region 242 reflects the distribution density of the first coating points 243 and the second coating points 244, which will affect the overall bonding strength and overall weight of the diaphragm 24.

[0095] Therefore, by setting the sum of the areas of all first coating points 243 and all second coating points 244 to the range described above, it is possible to better balance the overall bonding strength and overall weight of the diaphragm 24.

[0096] like Figure 5 As shown, in some embodiments, the area of ​​each second coating point 244 is larger than the area of ​​each first coating point 243.

[0097] It should be noted that the battery cell 20 also needs to be filled with electrolyte during use so that the electrode assembly 23 can be fully wetted with electrolyte. The ability of the electrode assembly 23 to be wetted with electrolyte will directly affect the performance of the battery cell 20.

[0098] The materials used for the first coating point 243 and the second coating point 244 are typically polyvinylidene fluoride (PVDF), polymethyl methacrylate (PMMA), ceramic particle mixed binder, and other materials with excellent electrolyte-loving properties. Therefore, the first coating point 243 and the second coating point 244 can adsorb and retain the electrolyte, thereby increasing the electrolyte storage capacity of the diaphragm 24.

[0099] Under this premise, increasing the area of ​​the second coating point 244 allows the middle position of the separator 24 to adsorb and retain more electrolyte through the second coating point 244, thereby improving the electrolyte retention capacity of the electrode assembly 23, enhancing the cycle life of the battery cell 20, and the sufficient electrolyte can also improve the ion transport capacity at low temperatures and reduce the probability of uneven internal reaction caused by uneven electrolyte retention in the electrode assembly 23.

[0100] Therefore, through the above structure, in addition to achieving a firm bond at the edge of the separator 24, the second coating point 244 can also improve the liquid retention capacity of the electrode assembly 23 and improve the performance of the battery cell 20.

[0101] In some embodiments, each first coating dot 243 is configured as a circular coating dot, and the diameter of each first coating dot 243 ranges from 50 μm to 100 μm.

[0102] Understandably, the shape of each first coating point 243 can be set to a square, rhombus or other shapes in addition to a circle. The specific shape can be adjusted according to the actual production situation, which will not be elaborated here.

[0103] When each first coating point 243 is constructed as a circular coating point, the diameter range of each first coating point 243 is set to 50μm~100μm.

[0104] As a specific embodiment, the diameter of each first coating point 243 may be set to, but is not limited to, 50μm, 60μm, 70μm, 80μm, 90μm, or 100μm.

[0105] Specifically, the diameter range of each first coating point 243 reflects the size of the first coating point 243, which directly affects the bonding strength at the edge of the diaphragm 24, thereby affecting the probability of an opening appearing at the edge of the electrode assembly 23.

[0106] By setting the diameter of each first coating point 243 to the aforementioned range, the adhesion strength at the edge of the diaphragm 24 can be better improved, thereby reducing the probability of openings appearing at the edge of the electrode assembly 23.

[0107] In some embodiments, the height of each first coating point 243 protruding from the surface of the diaphragm 24 is 5 μm to 10 μm.

[0108] As a specific embodiment, the height of each first coating point 243 protruding from the surface of the diaphragm 24 can be, but is not limited to, set to 5μm, 6μm, 7μm, 8μm, 9μm, or 10μm.

[0109] Specifically, the height at which each first coating point 243 protrudes from the surface of the diaphragm 24 is the thickness of each first coating point 243, representing the amount of adhesive at each first coating point 243.

[0110] Therefore, the height of each first coating point 243 protruding from the surface of the separator 24 is set to the above range, so that each first coating point 243 can better bond the separator 24 to the positive electrode or the negative electrode, and improve the bonding strength at the edge of the separator 24.

[0111] In some embodiments, each second coating dot 244 is configured as a circular coating dot, and the diameter of each second coating dot 244 ranges from 100 μm to 300 μm.

[0112] Understandably, the shape of each second coating point 244 can be set to a square, rhombus, or other shapes in addition to a circle. The specific shape can be adjusted according to the actual production situation, which will not be elaborated here.

[0113] When each second coating point 244 is constructed as a circular coating point, the diameter range of each second coating point 244 is set to 100μm~300μm.

[0114] As a specific embodiment, the diameter of each second coating point 244 can be, but is not limited to, set to 100μm, 150μm, 200μm, 250μm, or 300μm.

[0115] Specifically, the diameter range of each second coating point 244 reflects the size of the second coating point 244, affecting the bonding strength of the middle region of the diaphragm 24 and the overall weight of the diaphragm 24.

[0116] Thus, by setting the diameter of each second coating point 244 within the aforementioned range, it is possible to better balance the adhesive strength of the diaphragm 24 and the overall weight of the diaphragm 24.

[0117] In some embodiments, the height of each second coating point 244 protruding from the surface of the diaphragm 24 is 10 μm to 15 μm.

[0118] It should be noted that during the cycle, the electrode assembly 23 of the battery cell 20 will expand and deform as the working time accumulates, especially the middle large surface of the electrode assembly 23, which is the middle position of the separator 24, that is, the second region 242 where each second coating point 244 sits.

[0119] Based on this, the height at which each second coating point 244 protrudes from the surface of the separator 24 is the thickness of each second coating point 244. Increasing the thickness of each second coating point 244 can provide more space for expansion and deformation of the large surface of the battery cell 20, thereby improving the performance of the battery cell 20.

[0120] As a specific embodiment, the height of each second coating point 244 protruding from the surface of the diaphragm 24 can be, but is not limited to, set to 10μm, 11μm, 12μm, 13μm, 14μm, or 15μm.

[0121] Thus, by setting the height of each second coating point 244 protruding from the surface of the separator 24 to the range described above, more space for expansion and deformation can be provided for the large surface area of ​​the battery cell 20 corresponding to the second region 242, thereby improving the performance of the battery cell 20.

[0122] like Figure 6 As shown, in some embodiments, coating lines 245 connect adjacent first coating dots 243, and / or adjacent second coating dots 244, and / or adjacent first coating dots 243 and second coating dots 244.

[0123] As a first embodiment, coating lines 245 for connecting adjacent first coating points 243 can be provided, that is, adhesive lines are connected between adjacent first coating points 243.

[0124] As a second embodiment, coating lines 245 for connecting adjacent second coating points 244 can also be provided, that is, adhesive lines are connected between adjacent second coating points 244.

[0125] As a third embodiment, coating lines 245 can also be provided between adjacent first coating points 243, between adjacent second coating points 244, and between adjacent first coating points 243 and second coating points 244.

[0126] In this way, the coating lines 245 can further increase the coating area on the diaphragm 24, effectively improving the bonding strength of the diaphragm 24.

[0127] Based on the same concept as the battery cell 20 described above, this application also provides a battery device 100, including the battery cell 20 as described above.

[0128] Based on the same concept as the battery device 100 described above, this application also provides an electrical device including the battery device 100 as described above.

[0129] According to one or more embodiments, when this application is used, at least one row of first coating dots is first coated in the first region 241 of the diaphragm 24, and each row of first coating dots includes a plurality of first coating dots 243 spaced apart along the winding direction. At least one row of second coating dots is coated in the second region 242 of the diaphragm 24, and each row of second coating dots includes a plurality of second coating dots 244 spaced apart along the winding direction.

[0130] Then, the positive electrode, separator 24 and negative electrode are stacked in sequence, and the stacked positive electrode, separator 24 and negative electrode are wound and pressed and shaped to form electrode assembly 23.

[0131] During the assembly of the battery cell 20, the electrode assembly 23 is placed into the housing, electrolyte is injected into the housing through the injection hole on the housing, and then the injection hole is sealed to complete the assembly of the battery cell 20.

[0132] During the cycling process, the battery cell 20 has a small spacing between the first coating points 243 on the edge of the separator 24, meaning that the first coating points 243 are densely distributed on the edge of the separator 24. This effectively improves the adhesion strength of the edge of the separator 24, effectively reduces the probability of the electrode assembly 23 opening at the edge, and makes the battery cell 20 more stable.

[0133] Furthermore, since the area of ​​each second coating point 244 in the second region 242 is relatively large, the distribution is relatively sparse, and the thickness is relatively thick, it can not only improve the liquid retention of the separator 24, but also provide a larger space for expansion and deformation of the large surface of the battery cell 20, thereby improving the cycle life and performance of the battery cell 20.

[0134] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0135] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A battery cell, characterized in that, include: case; and An electrode assembly is disposed inside the housing and includes a positive electrode, a negative electrode, and a separator, wherein the positive electrode, the separator, and the negative electrode are sequentially stacked and wound to form the electrode assembly; The diaphragm has a first region and a second region on at least one surface, and the first region is located on at least one side of the second region in the winding direction of the electrode assembly; the first region is coated with at least one row of first coating dots arranged along the winding direction of the electrode assembly, and the second region is coated with at least one row of second coating dots arranged along the winding direction. In the first region, in the first row of first coating dots located at the edge of the diaphragm, the distance between two adjacent first coating dots is less than the distance between two adjacent second coating dots in any row of second coating dots. There are coating lines connecting adjacent first coating dots, and / or adjacent second coating dots, and / or adjacent first coating dots and second coating dots.

2. The battery cell according to claim 1, characterized in that, In the first region, in each of the other rows of the first coating group except for the first row of the first coating group, the distance between two adjacent first coating points is less than the distance between two adjacent second coating points in any row of the second coating group.

3. The battery cell according to claim 1 or 2, characterized in that, Within the first region, the distance between two adjacent first coating dots in the same row of the first coating dot group is the first distance; the distance between two adjacent rows of the first coating dot groups within the first region is the second distance. Wherein, the first spacing ranges from 100μm to 200μm; and / or, the second spacing ranges from 100μm to 200μm.

4. The battery cell according to claim 1 or 2, characterized in that, Within the second region, the spacing between two adjacent second coating dots in the same row of the second coating dot group is the third spacing; the spacing between two adjacent rows of the second coating dot group within the second region is the fourth spacing. Wherein, the third spacing ranges from 250μm to 500μm; and / or, the fourth spacing ranges from 250μm to 500μm.

5. The battery cell according to claim 1, characterized in that, The sum of the areas of each of the first coating points accounts for 20% to 60% of the total area of ​​all the first coating points and all the second coating points.

6. The battery cell according to claim 1, characterized in that, The sum of the areas of all the first and all the second coating points accounts for 8% to 23% of the total area of ​​the first and second regions.

7. The battery cell according to claim 1, characterized in that, The area of ​​each second coating point is greater than the area of ​​each first coating point.

8. The battery cell according to claim 7, characterized in that, Each of the first coating dots is constructed as a circular coating dot, and the diameter of each of the first coating dots ranges from 50 μm to 100 μm.

9. The battery cell according to claim 7, characterized in that, The height of each first coating point protruding from the surface of the diaphragm is 5μm~10μm.

10. The battery cell according to claim 7, characterized in that, Each of the second coating dots is constructed as a circular coating dot, and the diameter of each of the second coating dots ranges from 100 μm to 300 μm.

11. The battery cell according to claim 7, characterized in that, The height of each second coating point protruding from the surface of the diaphragm is 10μm~15μm.

12. A battery device, characterized in that, Includes the battery cell as described in any one of claims 1-11.

13. An electrical appliance, characterized in that, Includes the battery device as described in claim 12.

Images