Battery cell and electric device

Abstract

The application provides a battery monomer and an electric device. The battery monomer comprises a positive electrode sheet, a negative electrode sheet and an electrolyte, wherein the positive electrode sheet comprises a positive electrode current collector and a positive electrode film layer, the positive electrode current collector comprises a substrate layer, and the positive electrode film layer is arranged on at least one side of the substrate layer; a conductive layer is arranged on at least one side of the substrate layer, and comprises a first conductive structure arranged along the length direction of the substrate layer; and an insulating layer is arranged on the side of the conductive layer away from the substrate layer, the projection plane of the insulating layer on the substrate layer does not coincide with the projection plane of the positive electrode film layer on the substrate layer; and the conductivity of the conductive layer is greater than that of the substrate layer. The battery monomer provided by the application can effectively improve the current conduction capacity, optimize the current conduction path, and especially improve the safety and stability under the condition of rapid charging and discharging.

Description

Technical Field

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

[0002] Energy conservation and emission reduction are key to the sustainable development of the automotive industry, and electric vehicles, due to their energy-saving and environmentally friendly advantages, have become an important component of this sustainable development. For electric vehicles, battery technology is a crucial factor in their development. As electric vehicles increasingly demand higher driving ranges, faster charging speeds, and improved overall performance, batteries face a series of challenges during rapid charging and discharging.

[0003] During rapid charging and discharging, the high current density easily generates significant heat in the electrodes. If the temperature in these areas becomes too high, it reduces the battery's internal current transport capacity, leading to a decrease in charging and discharging efficiency. Overheating can also trigger chemical reactions or physical deformation of battery materials, thereby increasing safety risks such as short circuits and thermal runaway. Summary of the Invention

[0004] This application is made in view of the above-mentioned problems, and its purpose is to provide a battery cell whose positive electrode structure solves the problem of uneven current distribution and excessive local current causing overheating and reduced charging and discharging power during rapid charging and discharging at high rates, thereby improving the power performance and stability of the battery.

[0005] A first aspect of this application provides a battery cell, including a positive electrode, a negative electrode, and an electrolyte, wherein the positive electrode includes a positive current collector and a positive electrode film layer, the positive current collector includes a substrate layer, the positive electrode film layer is disposed on at least one side of the substrate layer; a conductive layer is disposed on at least one side of the substrate layer, including a first conductive structure disposed along the length direction of the substrate layer; and an insulating layer is disposed on the side of the conductive layer away from the substrate layer, the projection plane of the insulating layer on the substrate layer does not coincide with the projection plane of the positive electrode film layer on the substrate layer; the conductivity of the conductive layer is greater than the conductivity of the substrate layer.

[0006] In this embodiment, by using a conductive layer with high conductivity, the current preferentially passes through the conductive layer during rapid charging and discharging, increasing the conduction path and guiding the current to or out of the non-tab or distant areas. This results in a uniform current density within the substrate layer and reduces the overall resistivity of the positive electrode, thereby reducing the risk of excessive local current and overheating. The relatively fast current conduction rate can improve the power performance of the positive electrode and reduce the risk of thermal runaway.

[0007] In any embodiment, the substrate layer has a width dimension of W1 mm, and the first conductive structure includes N conductive strips that do not overlap along the width direction of the substrate layer, where N is a positive integer greater than or equal to 1. The sum of the dimensions of the N conductive strips along the width direction of the substrate layer is W2 mm, where W1 / W2 is in the range of 5 to 100. The conductive layer satisfies the effect of current conduction path optimization, further balances the current density distribution, and makes the current density distribution more uniform, effectively conducting current during high-rate charging and discharging of the battery cell; it does not occupy too much volume and does not excessively encroach on the space of the battery cell, ensuring the space occupied by the positive electrode active material, thereby ensuring the energy density of the battery cell.

[0008] In any implementation, 3 ≤ W2 ≤ 15, and can be selected as 9 ≤ W2 ≤ 13. When W2 meets the above range, it can be matched with the existing positive electrode preparation process without additional modification, avoiding the decrease in production efficiency and increase in cost caused by additional processes.

[0009] In any implementation, the N conductive strips have the same width. When the N conductive strips have the same width, the process can be simplified, and the same uniform current density is maintained for different current flow directions during charging and discharging, avoiding the situation where different widths lead to advantages in one operating condition and disadvantages in another.

[0010] In any embodiment, when N is greater than or equal to 2, the N conductive strips are symmetrically distributed, wherein the projection surfaces of the first and Nth conductive strips on the substrate layer fall into the projection surface of the insulating layer on the substrate layer. The symmetrical distribution of the N conductive strips allows for more uniform current conduction. When the projection surfaces of the first and Nth conductive strips on the substrate layer fall into the projection surface of the insulating layer on the substrate layer, the outermost conductive strip avoids occupying space in the positive electrode film layer by utilizing the space between the insulating layer and the substrate layer.

[0011] In any embodiment, when N is 1, the projection surface of the first conductive strip on the substrate layer falls into the projection surface of the insulating layer on the substrate layer. The conductive strip's proximity to the tab effectively balances current density, avoids temperature rise and heat generation, improves electrical transmission efficiency and safety, reduces the space occupied by the film layer, and helps the battery maintain high energy density.

[0012] In any embodiment, along the width direction of the substrate layer, the closest distance between the outer periphery of the projection surface of the first conductive strip on the substrate layer and the outer periphery of the substrate layer is 25mm-35mm. This distance provides space for die-cutting the tabs, avoids unnecessary coating, and controls production costs.

[0013] In any embodiment, the conductive layer further includes a second conductive structure. The included angle between the length direction of the second conductive structure and the length direction of the first conductive structure is between 10° and 170°, and there is an intersection point between the second conductive structure and the first conductive structure. The second conductive structure strengthens the conduction of current along the length direction of the substrate layer, further optimizes the current distribution in the middle of the substrate layer far from the tab, improves the stability of the battery, and is beneficial to the electrical transmission between the middle of the substrate layer and the positive active material in the positive electrode film layer.

[0014] In any embodiment, the size of the substrate layer in the thickness direction is H1 μm, where 8 ≤ H1 ≤ 16, and optionally, 10 ≤ H1 ≤ 15. When the size of the substrate layer in the thickness direction is within the above range, the current density can be further balanced, thus ensuring the stability under fast charge and discharge conditions.

[0015] In any embodiment, the size of the conductive layer in the thickness direction of the substrate layer is H2 μm, where H1:H2 = 0.25 - 0.75. When H1:H2 satisfies the above range, the larger thickness ensures the conduction path of the conductive layer, equalizes the current density, reduces heat generation, and can reduce problems such as stretching marks during rolling; at the same time, it avoids the peeling that is likely to occur when the conductive layer is too thick, reasonably controls the amount of conductive layer material used, and thus reduces the cost of the battery.

[0016] In any embodiment, the size of the insulating layer in the thickness direction of the substrate layer is H3 μm, where H1:H3 = 0.25 - 0.6. When H1:H3 satisfies the above range, the insulating layer can fully play the role of insulation, is not easily deformed or damaged during use, thus ensuring that the battery cell prevents the positive current collector from contacting the negative electrode or other metal components during use, thereby causing an internal short circuit; at the same time, it avoids the heat dissipation problem that may be caused by overcoating, which affects the thermal management system of the battery.

[0017] In any embodiment, the size of the positive electrode film layer in the thickness direction of the substrate layer is H4 μm, where H2 + H3 < H4. When H4 satisfies the above range, high stability of the battery cell can be achieved while further improving the energy density of the battery cell.

[0018] In any embodiment, the conductivity range of the conductive layer is 6*10 7 -10 8 S / m. When the conductivity range of the conductive layer satisfies the above range, during the fast charge and discharge process of the battery cell, the current transmission rate can be further increased, the current transmission path can be optimized, the heat generation of the substrate layer can be reduced, and the stability and charge-discharge efficiency of the lithium-ion battery can be improved.

[0019] In any embodiment, the conductive layer includes at least one of Al, Cu, Ni, Ag, Au, graphite, graphene, PANI, CNTs, RGO, SP, and EG. Both metallic and carbon materials have high electrical conductivity, which can optimize current transmission capabilities, and high thermal conductivity, which facilitates rapid heat dissipation and avoids heat accumulation.

[0020] In any embodiment, the insulating layer comprises at least one of AT11, PET, PP, PI, AlN, Si3N4, and BN. The insulating layer contains a polymer material, which can improve the adhesion between the insulating layer and the conductive layer and the positive electrode film layer through polymerization. The insulating layer contains inorganic materials, which can improve the hardness and stability of the insulating layer. Therefore, the insulating layer is not easily deformed or peeled off when subjected to external forces during the preparation and use of the battery cell.

[0021] The second aspect of this application provides an electrical device including a battery cell from the first aspect.

[0022] The positive electrode of the battery cell provided in this application has an added conductive layer on the current collector substrate layer, which can effectively improve the current conduction capability and optimize the current conduction path, especially the power performance and stability under fast charge and discharge conditions. Attached Figure Description

[0023] In the accompanying drawings, unless otherwise specified, the same reference numerals throughout the various drawings denote the same or similar parts or elements. These drawings are not necessarily drawn to scale. It should be understood that these drawings depict only some embodiments disclosed in this application and should not be construed as limiting the scope of this application.

[0024] Figure 1 This is a cross-sectional view of the positive electrode sheet in some embodiments of this application;

[0025] Figure 2 This is a cross-sectional view of the positive electrode sheet in some embodiments of this application;

[0026] Figure 3 This is a top view of the positive electrode sheet in some embodiments of this application;

[0027] Figure 4 This is a schematic diagram of a battery cell according to some embodiments of this application;

[0028] Figure 5 This is an exploded structural diagram of a battery cell according to some embodiments of this application;

[0029] Figure 6 This is a schematic diagram of an electrical device in which a single battery cell is used as a power source, according to some embodiments of this application.

[0030] Explanation of reference numerals in the attached figures:

[0031] 1. Battery cell; 10. Positive electrode plate; 11. Casing; 12. Electrode assembly; 13. Cover plate;

[0032] 110 Positive current collector; 120 Positive electrode film; 130 Tab;

[0033] 111 Substrate layer; 112 Conductive layer; 113 Insulating layer. Detailed Implementation

[0034] The following detailed description, with appropriate reference to the accompanying drawings, specifically discloses embodiments of the battery cell, battery device, and power-consuming device of this application. However, unnecessary detailed descriptions may be omitted. For example, detailed descriptions of well-known matters and repetitive descriptions of practically identical structures may be omitted. This is to avoid unnecessarily lengthy descriptions and to facilitate understanding by those skilled in the art. Furthermore, the accompanying drawings and the following description are provided for those skilled in the art to fully understand this application and are not intended to limit the subject matter of the claims.

[0035] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0036] Unless otherwise specified, all embodiments and optional embodiments of this application may be combined with each other to form new technical solutions, and such technical solutions should be considered to be included in the disclosure of this application.

[0037] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions, and such technical solutions shall be deemed to be included in the disclosure of this application.

[0038] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the method may also include step (c), indicating that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0039] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0040] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0041] The battery mentioned in the embodiments of this application can be a single physical module comprising one or more battery cells to provide higher voltage and capacity. For example, the battery mentioned in this application can include battery cells, battery modules, or battery packs.

[0042] A battery cell is the smallest unit that makes up a battery, and it can independently perform the functions of charging and discharging. A battery cell includes electrode components and an electrolyte.

[0043] Electrode assemblies typically include positive and negative electrodes. The negative electrode is the electrode that absorbs or lithiates lithium ions during charging and releases or delithiates lithium during discharging. The positive electrode is the electrode that absorbs or delithiates lithium ions during charging and absorbs or lithiates lithium during discharging.

[0044] In some implementations, such as Figure 1 and Figure 2As shown, the positive electrode 10 of the battery cell includes a positive current collector 110 and a positive electrode film layer 120. A conductive layer 112 is disposed on one side of the substrate layer 111, and an insulating layer 113 is disposed on the side of the conductive layer 112 away from the substrate layer 111. It is understood that the positive electrode film layer 120, conductive layer 112, and insulating layer 113 can also be disposed on both sides of the substrate layer 111. Wherein, the X direction represents the length direction of the substrate layer 111, the Y direction represents the width direction of the substrate layer 111, and the Z direction represents the thickness direction of the substrate layer 111.

[0045] In some implementations, such as Figure 3 As shown, the positive electrode 10 of the battery cell also includes a tab 130. It is understood that the number of tabs 130 can be one or more, and they can be disposed at one or both ends along the width direction of the substrate layer 111 as needed. The tabs can be prepared by die-cutting the substrate layer 111, or by welding tabs to the ends of the substrate layer 111.

[0046] The battery cell can be cylindrical, cuboid, or other shapes, and the embodiments of this application are not limited in this respect. Figure 4 Here is a cuboid-shaped battery cell 1 as an example.

[0047] The battery cell may also include an outer packaging, which can be used to encapsulate the electrode components and electrolyte. The outer packaging can be a rigid shell, such as a hard plastic shell, aluminum shell, or steel shell. The outer packaging can also be a flexible package, such as a pouch-type flexible package. The material of the flexible package can be plastic, such as one or more of polypropylene (PP), polybutylene terephthalate (PBT), and polybutylene succinate (PBS).

[0048] In some implementations, such as Figure 5 As shown, the outer packaging may include a housing 11 and a cover plate 13. The housing 11 may include a base plate and side plates connected to the base plate, the base plate and side plates enclosing a receiving cavity. The housing 11 has an opening communicating with the receiving cavity, and the cover plate 13 is used to cover the opening to close the receiving cavity. Electrode assemblies 12 are encapsulated in the receiving cavity. The number of electrode assemblies 12 contained in the battery cell 1 can be one or more, and can be adjusted according to requirements.

[0049] When there are multiple battery cells, they are connected in series, parallel, or mixed via a busbar. In some embodiments, the battery can be a battery module; when there are multiple battery cells, they are arranged and fixed to form a battery module. In some embodiments, the battery can be a battery pack, which includes a housing and battery cells, with the battery cells or battery modules housed within the housing. In some embodiments, the housing can be part of the vehicle's chassis structure. For example, a portion of the housing can be at least part of the vehicle's floor, or a portion of the housing can be at least part of the vehicle's crossbeams and longitudinal beams.

[0050] In some implementations, the battery can be an energy storage device. Energy storage devices include energy storage containers, energy storage cabinets, etc.

[0051] Lithium-ion batteries have garnered significant attention in electric vehicles and energy storage due to their core advantages: high energy density, long cycle life, and excellent power performance. However, during rapid charge and discharge, the electron and lithium-ion transport rate within the battery becomes a key factor limiting performance. High-rate charge and discharge can lead to uneven current density distribution on the electrode material surface, resulting in localized overheating and material degradation, which in turn hinders further improvements in the charge and discharge rate of lithium-ion batteries.

[0052] During the charging and discharging process of existing battery cells, electrons tend to flow to the external circuit via the shortest path. In the thickness direction, the current density near the outer surface of the current collector is higher, while the current in the central region is lower. Existing technologies have reduced the potential difference in the thickness direction by thinning the positive electrode current collector substrate layer, thus improving current transmission capacity. However, thinning the substrate layer slightly increases the overall resistance, leading to more significant ohmic losses during high-speed charging and discharging, resulting in substantial Joule heating. This heat accumulation causes the substrate layer to heat up, which in turn increases the substrate layer resistance, further degrading performance. Simultaneously, the current distribution varies across different regions along the length and width of the current collector surface. Regions with higher current density age prematurely due to more frequent reactions, shortening the overall battery life. How to effectively improve the power performance and stability of lithium-ion batteries under fast charging conditions is a pressing technical problem that needs to be solved in this field.

[0053] To address the aforementioned issues, the first aspect of this application provides a battery cell, which includes a positive electrode, a negative electrode, and an electrolyte. The positive electrode 10 is described in [reference needed]. Figure 1 and Figure 3The device includes a positive current collector 110 and a positive electrode film layer 120. The positive current collector 110 includes a substrate layer 111, and the positive electrode film layer 120 is disposed on at least one side of the substrate layer 111. A conductive layer 112 is disposed on at least one side of the substrate layer 111 and is disposed along the length direction of the substrate layer 111. An insulating layer 113 is disposed on the side of the conductive layer 112 away from the substrate layer 111, and the projection plane of the insulating layer 113 on the substrate layer 111 does not coincide with the projection plane of the positive electrode film layer 120 on the substrate layer 111. The conductivity of the conductive layer 112 is greater than the conductivity of the substrate layer 111.

[0054] Please continue reading Figure 1 and Figure 3 The length direction of the substrate layer 111 refers to the dimension of the substrate layer 111 in the direction parallel to the rolling of the positive electrode film layer 120 in the positive electrode sheet 10 (i.e., Figure 3 (in the X direction). The width direction of the substrate layer 111 refers to the dimension of the substrate layer 111 in the direction perpendicular to the rolling of the positive electrode film layer 120 in the positive electrode sheet 10 (i.e., the width direction of the substrate layer 111). Figure 1 and Figure 3 center Y direction).

[0055] In this embodiment of the application, the positive electrode sheet further includes a tab, which is disposed at one end of the substrate layer near the insulating layer in the width direction.

[0056] In this embodiment, the positive electrode film layer is disposed on at least one side of the substrate layer away from the tab along the width direction of the substrate layer.

[0057] In this embodiment, the positive electrode film layer and the conductive layer are disposed on the same side of the substrate layer.

[0058] In this embodiment, the insulating layer is disposed on the side of the conductive layer away from the substrate layer, and the projection plane of the insulating layer on the substrate layer does not coincide with the projection plane of the positive electrode film layer on the substrate layer. This avoids unnecessary electrical contact between the conductive layer, the positive electrode film layer, and other components during battery assembly, thereby preventing short circuits or current leakage; furthermore, the insulating layer can effectively isolate most of the contact between the conductive layer and the electrolyte, reducing potential chemical damage and improving the long-term stability of the battery.

[0059] In this application, "electrical conductivity" has a well-known meaning in the art and can be used to characterize the strength of a material's ability to conduct electric current. The higher the electrical conductivity, the stronger the current conduction ability.

[0060] In this application, the conductivity of the substrate layer and the conductive layer can be detected by any method known in the art. As an example, an RTS-9 dual-electrical-measurement four-probe tester can be used. The test environment is: room temperature 23±2℃, relative humidity ≤65%. During the test, the surface of the material to be tested is cleaned, and then it is placed horizontally on the test stage. The four probes are lowered to ensure good contact between the probes and the surface of the sample. Then, the current range of the material is calibrated by adjusting the automatic test mode. The conductivity is measured under a suitable current range, and 8 to 10 data points of the same sample are collected for data measurement accuracy and error analysis, in units of S / m.

[0061] In some embodiments, the length of the conductive layer along the length direction of the substrate layer is greater than or equal to half the length of the substrate layer.

[0062] In some embodiments, the length of the conductive layer along the length direction of the substrate layer is equal to the length of the substrate layer.

[0063] In the positive current collector of this application embodiment, by setting a conductive layer with high conductivity, the current preferentially passes through the conductive layer during rapid charging and discharging, which increases the conduction path and guides the current to flow to or out of the non-tab or far away from the tab area, so that the current density inside the substrate layer is uniform and the overall resistivity of the positive electrode sheet is reduced, thereby reducing the risk of excessive local current and heat generation. The current conduction rate is relatively fast, which can ensure the rapid charging and discharging capability and stability of the positive electrode sheet and reduce the risk of thermal runaway.

[0064] In some embodiments, the substrate layer has a width dimension of W1 mm, the first conductive structure includes N conductive strips, the N conductive strips are symmetrically distributed along the width direction of the substrate layer and do not overlap, where N is a positive integer greater than or equal to 1, the sum of the dimensions of the N conductive strips along the width direction of the substrate layer is W2 mm, where W2 / W1 is in the range of 5 to 100.

[0065] The dimensions of the substrate layer, the conductive layer, and the substrate layer along its width direction can be inspected using any method known in the art. For example, a vernier caliper can be used to measure the width of the substrate layer at at least four different locations along its width direction, and the average value can be taken as the dimension W1 of the substrate layer's width. Then, a micrometer can be used to measure the width of each conductive strip at at least four different locations along the width direction of the substrate layer, and the average value of each conductive strip's width can be added together as the dimension W2 of the conductive strip along the width direction of the substrate layer.

[0066] In some implementations, W1 / W2 can be selected as 5, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 95, 100 or any range of two.

[0067] When W1 / W2 is within the above range, the conductive layer satisfies the effect of current conduction path optimization, which can further balance the current density distribution and make the current density distribution more uniform. It can effectively conduct current when the battery cell is charged and discharged at a high rate. Moreover, the conductive layer cannot provide energy to the battery cell, so the volume occupied by the conductive structure will not be too large and will not excessively encroach on the space of the battery cell, thus ensuring the space occupied by the positive electrode active material and ensuring the energy density of the battery cell.

[0068] In some implementations, 3≤W2≤15, and can be selected as 9≤W2≤13.

[0069] In some implementations, W2 can be selected as a numerical range of 9, 10, 11, 12, 13, 14, 15 or any two of these.

[0070] When W2 meets the above range, it can be matched with the existing positive electrode preparation process without additional modification, thus avoiding the decrease in production efficiency and increase in cost caused by additional processes.

[0071] In some implementations, the N conductive strips have the same width.

[0072] When all N conductive strips have the same width, the manufacturing process can be simplified. At the same time, the same high current conduction effect is maintained for different current flows during charging and discharging, avoiding the situation where different widths lead to advantages in one working condition and disadvantages in another.

[0073] In some embodiments, when N is greater than or equal to 2, the N conductive strips are symmetrically distributed, wherein the projection surfaces of the first conductive strip and the Nth conductive strip on the substrate layer fall into the projection surface of the insulating layer on the substrate layer.

[0074] In some embodiments, the first conductive strip, the Nth conductive strip, and the insulating layer are in direct contact.

[0075] The N conductive strips are symmetrically distributed, which can conduct current more evenly. When the projection surfaces of the first and Nth conductive strips on the substrate layer fall into the projection surface of the insulating layer on the substrate layer, the outermost conductive strip avoids occupying space in the positive electrode film layer by utilizing the space between the insulating layer and the substrate layer.

[0076] In some embodiments, when N equals 1, the projection surface of the first conductive strip on the substrate layer falls into the projection surface of the insulating layer on the substrate layer.

[0077] When N equals 1, the projection surface of the first conductive strip on the substrate layer falls into the projection surface of the insulating layer on the substrate layer. The conductive strip's placement close to the electrode tab effectively balances current density, avoids temperature rise and heat generation, improves electrical transmission efficiency and safety, reduces the space occupied by the film layer, and helps the battery maintain high energy density.

[0078] In some implementations, N equals 2. When N equals 2, the current transmission path in the region far from the tab is further optimized, which is particularly suitable for structures with tabs at both ends along the width direction of the substrate layer.

[0079] In some embodiments, along the width direction of the substrate layer, the closest distance between the outer periphery of the projection surface of the first conductive strip on the substrate layer and the outer periphery of the substrate layer is 25mm-35mm.

[0080] This distance allows for die-cutting space for the tabs, avoiding unnecessary coating and controlling production costs.

[0081] In some embodiments, the conductive layer further includes a second conductive structure, wherein the angle between the length direction of the second conductive structure and the length direction of the first conductive structure is between 10° and 170°, and the second conductive structure intersects with the first conductive structure at a point.

[0082] In some embodiments, the angle between the length direction of the second conductive structure and the length direction of the first conductive structure can be selected as 10°, 20°, 30°, 40°, 50°, 60°, 70°, 80°, 90°, 100°, 110°, 120°, 130°, 140°, 150°, 160°, 170° or any value range between the two.

[0083] The second conductive structure enhances the conduction of current along the length of the substrate layer, further optimizes the current distribution in the middle of the substrate layer away from the tab, improves the stability of the battery, and facilitates the electrical transport between the middle of the substrate layer and the positive electrode active material in the positive electrode film layer.

[0084] In some embodiments, the dimension of the substrate layer along the thickness direction is H1 μm, wherein 8 ≤ H1 ≤ 16, and optionally 10 ≤ H1 ≤ 15.

[0085] The dimension of the substrate layer along its thickness direction can be measured using any method known in the art. As an example, the thickness of the substrate layer can be measured at at least four different locations along its thickness direction using a micrometer, and the average value can be taken as the thickness dimension H1 of the substrate layer.

[0086] In some implementations, H1 can be selected as a numerical range of 8, 9, 10, 11, 12, 13, 14, 15, 16 or any two of these.

[0087] When the dimensions of the substrate layer along the thickness direction are within the above range, it can further balance the current density, thereby ensuring the stability of rapid charging and discharging.

[0088] In some embodiments, the dimension of the conductive layer along the thickness direction of the substrate layer is H2μm, where H1:H2 = 0.25-0.75.

[0089] The dimension of the conductive layer along the thickness direction of the substrate layer can be measured using any method known in the art. As an example, the thickness of the conductive layer can be measured at at least four different locations along the thickness direction of the substrate layer using a micrometer, and the average value can be taken as the dimension H2 of the conductive layer thickness.

[0090] In some implementations, H1:H2 can be selected as 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6, 0.65, 0.7, 0.75 or any range between the two.

[0091] When H1:H2 meets the above range, the larger thickness ensures the conductive path of the conductive layer, uniforms the current density, reduces heat generation, and can reduce the generation of problems such as stretch marks during rolling; at the same time, it avoids the peeling that is easy to occur when the conductive layer is too thick, and the amount of conductive layer material used can be reasonably controlled, thereby reducing the cost of the battery.

[0092] In some embodiments, the dimension of the insulating layer along the thickness direction of the substrate layer is H3μm, where H1:H3 = 0.25-0.6.

[0093] The dimension of the insulating layer along the thickness direction of the substrate layer can be measured by any method known in the art. As an example, the thickness of the conductive layer at at least four different locations along the width direction of the insulating layer can be measured using a micrometer, and the average value can be taken as the dimension H2 of the conductive layer thickness.

[0094] In some implementations, H1:H3 can be selected as 0.25, 0.3, 0.35, 0.4, 0.45, 0.5, 0.55, 0.6 or any range between the two.

[0095] When H1:H3 meets the above range, the insulating layer can fully perform its insulating function and is not easily deformed or damaged during use. This ensures that the positive current collector of the battery cell does not come into contact with the negative electrode or other metal components during use, thereby preventing internal short circuits. At the same time, it avoids the possibility that excessive coating may cause heat dissipation problems and affect the battery's thermal management system.

[0096] In some embodiments, the dimension of the positive electrode film layer along the thickness direction of the substrate layer is H4μm, wherein H2+H3 <H4。

[0097] The dimensions of the positive electrode film layer along the thickness direction of the substrate layer can be measured using any method known in the art. As an example, the thickness of the positive electrode film layer can be measured at at least four different locations along the width direction of the insulating layer using a micrometer, and the average value can be taken as the thickness dimension H4 of the positive electrode film layer.

[0098] When H4 meets the above range, it can achieve high stability of battery cells while further improving the energy density of battery cells.

[0099] In some embodiments, the conductivity of the conductive layer is in the range of 6*10. 7 -10 8 S / m.

[0100] When the conductivity of the conductive layer meets the above-mentioned range, it can further improve the current transmission rate, optimize the current transmission path, reduce the heating of the substrate layer, and improve the stability and charging / discharging efficiency of the lithium-ion battery during the rapid charging and discharging process of the battery cell.

[0101] In some embodiments, the conductive layer includes at least one of Al, Cu, Ni, Ag, Au, graphite, graphene, PANI, CNTs, RGO, SP, and EG.

[0102] The conductive layer comprises at least one metallic material and a carbon material. Examples of metallic materials include Al, Cu, Ni, Ag, and Au; examples of carbon materials include graphite, graphene, PANI, CNTs, RGO, SP, and EG. Both metallic and carbon materials possess high electrical conductivity, which optimizes current transmission, and high thermal conductivity, which facilitates rapid heat dissipation and prevents heat accumulation.

[0103] In some embodiments, the insulating layer includes at least one of AT11, PET, PP, PI, AlN, Si3N4, and BN.

[0104] The insulating layer comprises at least one polymeric material and an inorganic material. Examples of polymeric materials include resins such as PET, PP, and PI. The inclusion of polymeric materials in the insulating layer enhances the bonding between the insulating layer and the conductive and positive electrode films through polymerization. Examples of inorganic materials include AlN, Si3N4, and BN. The inclusion of inorganic materials in the insulating layer improves its hardness and stability. Therefore, the insulating layer is less prone to deformation and peeling under external forces during battery cell manufacturing and use.

[0105] In some embodiments, the substrate layer may be a metal foil or a composite current collector. For example, aluminum foil may be used as the metal foil. The composite current collector may include a polymeric material substrate and a metal layer formed on at least one surface of the polymeric material substrate. The composite current collector may be formed by forming a metal material (aluminum, aluminum alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymeric material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0106] In some embodiments, the positive electrode film layer includes a positive electrode active material. The positive electrode active material may be any negative or positive electrode active material known in the art for use in batteries. As an example, the positive electrode active material may include at least one of the following materials: lithium cobalt oxide, lithium iron phosphate, lithium manganese iron phosphate, lithium vanadium phosphate, lithium vanadium oxide phosphate, lithium vanadium oxide, and lithium manganese oxide. However, this application is not limited to these materials, and other conventional materials that can be used as positive electrode active materials for batteries may also be used. These positive electrode active materials may be used alone or in combination of two or more.

[0107] In some embodiments, the positive electrode film may optionally include a conductive agent. As an example, the conductive agent may include at least one selected from superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0108] In some embodiments, the positive electrode film layer may optionally include a binder. As an example, the binder may include at least one selected from polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), PVDF-tetrafluoroethylene-propylene terpolymer, PVDF-hexafluoropropylene-tetrafluoroethylene terpolymer, tetrafluoroethylene-hexafluoropropylene copolymer, and fluorinated acrylate resin.

[0109] In some embodiments, the positive electrode sheet can be prepared by: applying the conductive layer to at least one side of a substrate layer, and then applying an insulating layer to the side of the conductive layer away from the substrate layer to form a positive current collector. The application method can be coating, electroplating, or spraying, but is not limited to these. Components used to prepare the positive electrode film layer, such as positive electrode active material, conductive agent, polymer binder, and any other components, are dispersed in a solvent to form a positive electrode slurry; the positive electrode slurry is coated onto at least one side of the positive current collector, and after drying, cold pressing, and other processes, the positive electrode sheet is obtained. The solid content of the positive electrode slurry can be 40wt%-80wt%. The viscosity of the positive electrode slurry at room temperature can be adjusted to 5000 mPa·s-25000 mPa·s.

[0110] In some embodiments, the negative electrode sheet includes a negative current collector and a negative electrode film layer disposed on at least one side of the negative current collector.

[0111] In some embodiments, the negative electrode current collector may be a metal foil or a composite current collector. For example, copper foil may be used as the metal foil. The composite current collector may include a polymer material substrate and a metal layer formed on at least one surface of the polymer material substrate. The composite current collector may be formed by forming a metal material (copper, copper alloy, nickel, nickel alloy, titanium, titanium alloy, silver and silver alloy, etc.) on a polymer material substrate (such as a substrate of polypropylene (PP), polyethylene terephthalate (PET), polybutylene terephthalate (PBT), polystyrene (PS), polyethylene (PE), etc.).

[0112] In some embodiments, the negative electrode film layer includes a negative electrode active material. The negative electrode active material may be any negative electrode active material known in the art for use in batteries. As an example, the negative electrode active material may include at least one of the following materials: artificial graphite, natural graphite, soft carbon, hard carbon, silicon-based materials, tin-based materials, and lithium titanate, etc. The silicon-based material may be selected from at least one of elemental silicon, silicon oxide compounds, silicon-carbon composites, silicon-nitrogen composites, and silicon alloys. The tin-based material may be selected from at least one of elemental tin, tin oxide compounds, and tin alloys. However, this application is not limited to these materials, and other conventional materials that can be used as negative electrode active materials for batteries may also be used. These negative electrode active materials may be used alone or in combination of two or more.

[0113] In some embodiments, the negative electrode film layer may optionally include a binder. As an example, the binder may be selected from at least one of styrene-butadiene rubber (SBR), polyacrylic acid (PAA), sodium polyacrylate (PAAS), polyacrylamide (PAM), polyvinyl alcohol (PVA), sodium alginate (SA), polymethacrylic acid (PMAA), and carboxymethyl chitosan (CMCS).

[0114] In some embodiments, the negative electrode film may optionally include a conductive agent. As an example, the conductive agent may be selected from at least one of superconducting carbon, acetylene black, carbon black, Ketjen black, carbon dots, carbon nanotubes, graphene, and carbon nanofibers.

[0115] In some embodiments, the negative electrode film may optionally include other additives, such as thickeners (e.g., sodium carboxymethyl cellulose (CMC-Na)).

[0116] In some embodiments, the negative electrode sheet can be prepared by dispersing the components used to prepare the negative electrode sheet, such as the negative electrode active material, conductive agent, binder and any other components, in a solvent (e.g., deionized water) to form a negative electrode slurry; coating the negative electrode slurry onto the negative electrode current collector, and then obtaining the negative electrode sheet after drying, cold pressing and other processes.

[0117] In some embodiments, the battery cell includes an electrolyte. The electrolyte acts as a conductor of ions between the positive and negative electrodes. This application does not impose specific limitations on the type of electrolyte, which can be selected according to requirements. For example, the electrolyte can be liquid, gel-like, or entirely solid-state.

[0118] In some embodiments, the electrolyte is an electrolyte solution. The electrolyte solution includes an electrolyte salt and a solvent.

[0119] In some embodiments, the electrolyte salt may be selected from at least one of lithium hexafluorophosphate, lithium tetrafluoroborate, lithium perchlorate, lithium hexafluoroarsenate, lithium bis(fluorosulfonyl)imide, lithium bis(trifluoromethanesulfonyl)imide, lithium trifluoromethanesulfonate, lithium difluorophosphate, lithium difluorooxalate borate, lithium dioxalate borate, lithium difluorodioxalate phosphate, and lithium tetrafluorooxalate phosphate.

[0120] In some embodiments, the solvent may be selected from at least one of ethylene carbonate, propylene carbonate, methyl ethyl carbonate, diethyl carbonate, dimethyl carbonate, dipropyl carbonate, methyl propyl carbonate, ethyl propyl carbonate, butyl carbonate, fluoroethylene carbonate, methyl formate, methyl acetate, ethyl acetate, propyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, 1,4-butyrolactone, sulfolane, dimethyl sulfone, methyl ethyl sulfone, and diethyl sulfone.

[0121] In some embodiments, the electrolyte may optionally include additives. For example, additives may include negative electrode film-forming additives, positive electrode film-forming additives, and may also include additives that can improve certain battery performance, such as additives that improve battery overcharge performance, additives that improve battery high-temperature or low-temperature performance, etc.

[0122] In some embodiments, the battery cell also includes a separator. This application does not impose any particular limitation on the type of separator; any known porous separator with good chemical and mechanical stability can be selected.

[0123] In some embodiments, the material of the separator can be selected from at least one of glass fiber, nonwoven fabric, polyethylene, polypropylene, and polyvinylidene fluoride. The separator can be a single-layer film or a multi-layer composite film, without particular limitation. When the separator is a multi-layer composite film, the materials of each layer can be the same or different, without particular limitation.

[0124] In some implementations, the positive electrode, negative electrode, and separator can be fabricated into an electrode assembly using a winding or stacking process.

[0125] In some embodiments, the battery cell may include an outer packaging. This outer packaging can be used to encapsulate the electrode assembly and electrolyte described above.

[0126] In some embodiments, the outer packaging of the battery cell can be a rigid shell, such as a hard plastic shell, an aluminum shell, or a steel shell. The outer packaging of the battery cell can also be a flexible package, such as a pouch. The material of the flexible package can be plastic; examples of plastics include polypropylene, polybutylene terephthalate, and polybutylene succinate.

[0127] This application does not impose any particular restrictions on the shape of the battery cell; it can be cylindrical, square, or any other arbitrary shape.

[0128] A second aspect of this application provides an electrical device, including the battery cell provided in this application. The battery cell can be used as a power source for the electrical device or as an energy storage unit for the electrical device. The electrical device may include, but is not limited to, mobile devices (e.g., mobile phones, laptops, etc.), electric vehicles (e.g., 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.

[0129] As an electrical device, you can choose individual battery cells, battery modules, or battery packs according to your usage requirements.

[0130] Figure 6 This is an example of an electrical device. The electrical device could be a pure electric vehicle, a hybrid electric vehicle, or a plug-in hybrid electric vehicle, etc.

[0131] Another example device could be a mobile phone, tablet, or laptop. These devices typically require a slim and lightweight design and can use a single battery cell as their power source.

[0132] Example

[0133] The following describes embodiments of this application. The embodiments described below are exemplary and are only used to explain this application, and should not be construed as limiting this application. Where specific techniques or conditions are not specified in the embodiments, they are performed according to the techniques or conditions described in the literature in this field or according to the product instructions. Reagents or instruments used, unless otherwise specified, are all conventional products that can be obtained commercially.

[0134] I. Preparation Method

[0135] Example 1

[0136] 1. Preparation of positive electrode sheet

[0137] Aluminum foil is used as the positive current collector substrate layer, with a width dimension of 260 mm and a thickness of 13 μm. Metallic silver powder is used as the conductive layer material and is coated along the length of the substrate layer onto its surface in one strip. The first conductive strip has a width of 9 mm and a thickness of 26 μm, and the closest distance between the outer periphery of the projection surface of the first conductive strip on the substrate layer and the outer periphery of the substrate layer is 30 mm. AT11 insulating material is coated onto the side of the conductive layer away from the substrate layer surface to form an insulating layer. The insulating layer has a width of 9 mm and a thickness of 33 μm, and the projection of the insulating layer on the substrate layer completely coincides with the projection of the conductive layer on the substrate layer.

[0138] NCM111 material, conductive carbon black, and binder polyvinylidene fluoride (PVDF) are mixed evenly at a weight ratio of 97:2:1 to obtain a positive electrode slurry. The positive electrode slurry is uniformly coated onto the positive electrode current collector substrate layer to a thickness of 75 μm to form a positive electrode film layer. The projection surface of the positive electrode film layer on the substrate layer does not overlap with the projection screens of the conductive layer and the insulating layer on the substrate layer. After drying, cold pressing, and slitting, a positive electrode sheet is obtained.

[0139] 2. Preparation of negative electrode sheet

[0140] Artificial graphite, conductive carbon black, styrene-butadiene rubber (SBR) binder, and sodium carboxymethyl cellulose (CMC) thickener were dissolved in deionized water at a weight ratio of 97:0.4:1.5:1.1 and mixed evenly to prepare a first active slurry. Artificial graphite, conductive carbon black, styrene-butadiene rubber (SBR) binder, and sodium carboxymethyl cellulose (CMC) thickener were dissolved in deionized water at a weight ratio of 97.3:0.7:0.9:1.1 and mixed evenly to prepare a second active slurry. The first active slurry was coated onto the surface of the current collector copper foil and dried to form a first active layer. Then, the second slurry was coated on top of the first active layer, dried, cold-pressed, and slit to obtain the negative electrode sheet.

[0141] 3. Preparation of electrolyte

[0142] In an argon atmosphere glove box (H2O<0.1ppm, O2<0.1ppm), the organic solvents ethylene carbonate (EC) and ethyl methyl carbonate (EMC) were mixed evenly at a volume ratio of 3 / 7. Then, 1 mol / L LiPF6 lithium salt was added and dispersed evenly. The mixture was stirred evenly to obtain the electrolyte.

[0143] 4. Preparation of the separating membrane

[0144] PE porous film is used as the separator.

[0145] 5. Preparation of battery cells

[0146] The prepared positive and negative electrode sheets are die-cut to form electrode tabs; they are stacked in the order of "separator-negative electrode sheet-separator-positive electrode sheet" and wound in the same direction to obtain the electrode assembly; after hot pressing, assembly into the shell, injection of prepared electrolyte, high-temperature standing, formation, electrolyte replenishment, aging and other processes, a wound battery is obtained.

[0147] Specific parameters are shown in Table 1.

[0148] Example 2-11

[0149] The preparation methods of Examples 2-6 are basically the same as those of Example 1, except that the structure of the positive electrode sheet of the battery cell is adjusted. The specific parameters are shown in Table 1.

[0150] The preparation method of the comparative example is basically the same as that of Example 1, except that the positive current collector of the positive electrode sheet of the battery cell does not have a conductive layer. The specific parameters are shown in Table 1.

[0151] II. Testing Methods

[0152] 1. DCR test

[0153] ① At 25°C, the battery cells prepared in each example and comparative example were charged to 4.4V at a constant current rate of 1 / 3C, then charged to 0.05C at a constant voltage rate, and discharged to 50% SOC at a constant current rate of 1 / 3C; discharged at a 4C rate for 30s, and then charged at a 4C rate for 30s to obtain the discharge and charge DCR data at 25°C and 50% SOC; continued to discharge at a constant current rate of 1 / 3C to 20% SOC, then discharged at a 4C rate for 30s, and then charged at a 4C rate for 30s to obtain the discharge and charge DCR data at 25°C and 20% SOC.

[0154] ② At -25℃, take the battery cells prepared in each example and comparative example, charge them at a constant current rate of 1 / 3C to 4.4V, then charge them at a constant voltage rate to 0.05C, and discharge them at a constant current rate of 1 / 3C to 50% SOC; discharge them at a 4C rate for 30s, and then charge them at a 4C rate for 30s to obtain the discharge and charge DCR data at 25℃ and 50% SOC; continue to discharge them at a constant current rate of 1 / 3C to 20% SOC, then discharge them at a 4C rate for 30s, and then charge them at a 4C rate for 30s to obtain the discharge and charge DCR data at 25℃ and 20% SOC.

[0155] 2. Temperature rise test

[0156] ①CAP test: At 25℃, take the battery cells prepared in each example and comparative example, discharge them at a constant current rate of 1 / 3C to 2.5V, then charge them at a constant current rate of 1 / 3C to 4.4V, then charge them at a constant voltage rate to 0.05C, and finally discharge them at a constant current rate of 1 / 3C to 2.5V. The measured Cap is recorded as C0.

[0157] ②SOC-OCV Calibration: At 25℃, take the battery cells prepared in each example and comparative example, charge them at a constant current rate of 1 / 3C to 4.4V, then charge them at a constant voltage rate to 0.05C, and then discharge them at a constant current rate of 1 / 3C to 0.97C0. The voltage at this point is calibrated to be V, and the state of charge is 3% SOC; after resting, charge them at a constant current rate of 1.5C0 for 2%. C0 is used to calibrate the voltage to V1, with a state of charge (SOC) of 5%. Then, 6C0 is used to charge the battery to 10%, 15%, 20%, 25%, and 30% SOC, calibrating the voltages to V2, V3, V4, V5, V6… Next, using C0 at rates of 5.53 / 5.03 / 4.62 / 4.28 / 3.97 / 3.7 / 3.44 / 3.2 / 2.95 / 2.7 / 2.0 / 1.3 / 0.6 / 0.33, the battery is charged to 35% / 40% / 45% / 50% / 55% / 60% / 65% / 70% / 75% / 80% / 85% / 90% / 95% / 97% SOC, and the voltages are calibrated to V7 / …V. 20 Finally, discharge at a constant current rate of 1 / 3 CO to 2.5V, and adjust the state of charge to 0% SOC;

[0158] ③ Cycling: After resting, charge the cells to V1 / V6 / … / V using current densities of 1.5 / 6 / 5.53 / 5.03 / 4.62 / 4.28 / 3.97 / 3.7 / 3.44 / 3.2 / 2.95 / 2.7 / 2.0 / 1.3 / 0.6 / 0.33C0 respectively. 20 Finally, the voltage was discharged from 0.5C0 to 2.5V, and the cycle was repeated 3 times to obtain the temperature-SOC-current relationship.

[0159] III. Test Results

[0160] The test results of the above embodiments and comparative examples are shown in Table 1.

[0161] Table 1

[0162]

[0163] The battery cells in Examples 1-11 include a positive electrode, a negative electrode, and an electrolyte. The positive electrode includes a positive current collector and a positive electrode film. The positive current collector includes a substrate layer, and the positive electrode film is disposed on at least one side of the substrate layer. A conductive layer is disposed on at least one side of the substrate layer, including a first conductive structure disposed along the length of the substrate layer. An insulating layer is disposed on the side of the conductive layer away from the substrate layer, and the projection plane of the insulating layer on the substrate layer does not coincide with the projection plane of the positive electrode film on the substrate layer. The conductivity of the conductive layer is greater than that of the substrate layer. Compared with the comparative examples, the battery cells using a conductive layer with high conductivity on the surface of the substrate layer in Examples 1 to 11 are beneficial for reducing the DC internal resistance of the battery cell at 25°C, improving charge and discharge efficiency, and reducing temperature rise. The power performance and safety of the battery are also improved.

[0164] In Examples 1 and 2, the conductivity of the conductive layer was adjusted. When the conductivity of the conductive layer is higher than that of the substrate layer, the DC internal resistance of the battery can be effectively reduced, and the temperature rise can be decreased. The conductivity range of the conductive layer is 5*10⁻⁶. 7 -10 8 S / m, by reducing the internal resistance of the conductive layer and increasing the conductivity, is more conducive to current conduction, avoids heat conversion loss in the conductive layer, and further improves the overall performance and safety of the battery.

[0165] Compared to Examples 1, 3, and 4, the current collector width and the dimensions of the conductive layer along the width of the substrate layer were adjusted. It can be seen that for positive electrode sheets with conductive layer structures, as the proportion of the conductive layer width increases, more current paths are provided. At 25°C, the battery's DC internal resistance shows a decreasing trend, and the temperature rise and charging time are also reduced accordingly. With W1 / W2 in the range of 5 to 100, excessive encroachment of the conductive layer on the active material space is avoided, balancing energy density and electrical performance.

[0166] Compared to Examples 1, 5, and 6, the dimensions of the current collector along the thickness direction were adjusted. Electrons tend to flow to the external circuit via the shortest path, resulting in a higher current density near the outer region of the current collector and a lower current density in the central region. A thinner current collector reduces the internal potential difference, allowing the current to cover the entire electrode more evenly and preventing electrons from accumulating in localized areas, which could lead to excessively high local current density and hot spots. However, if the current collector is too thin, according to Ohm's law (lateral resistance R = ρ*L / A), a smaller cross-sectional area will increase the overall resistance. Therefore, a substrate layer with a thickness of 8mm to 16mm is necessary to effectively reduce the battery's DC internal resistance.

[0167] Compared with Examples 1, 7, and 8, the dimensions of the conductive layer along the thickness direction were adjusted. When the ratio of the dimensions of the substrate layer along the thickness direction to the dimensions of the conductive layer along the thickness direction is between 0.25 and 0.75, it is beneficial to keep the DC internal resistance of the battery at a low level. At the same time, the conductive layer material is a metal or carbon-based material, which has a high thermal conductivity, which can further optimize heat dissipation, reduce temperature rise, and avoid the degradation of power performance due to heat accumulation.

[0168] Compared to Examples 1, 9, and 10, the dimensions of the insulating layer along its thickness direction were adjusted. When the ratio of the substrate layer's dimension along its thickness direction to the insulating layer's dimension along its thickness direction is between 0.25 and 0.6, internal short circuits caused by contact between the positive and negative electrode plates inside the battery can be avoided. An excessively thick insulating layer hinders heat dissipation from the current collector, leading to a significant temperature rise during charging and increasing DC internal resistance, thus affecting power performance.

[0169] Compared with Example 11, Example 11 includes two conductive strips. The conductive strips are symmetrically distributed along the width of the substrate layer, providing an additional current transmission path on the side away from the tab, which is beneficial to further reduce the DC internal resistance of the battery, the 10% to 80% SOC temperature rise and the charging time.

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and not to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. These modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application, and they should all be covered within the scope of the claims and specification of this application. In particular, as long as there is no structural conflict, the various technical features mentioned in the embodiments can be combined in any way. This application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

1. A battery cell, characterized in that, Includes positive electrode, negative electrode, and electrolyte. The positive electrode includes a positive current collector and a positive electrode film. The positive electrode current collector includes A substrate layer, wherein the positive electrode film layer is disposed on at least one side of the substrate layer; A conductive layer is disposed on at least one side of the substrate layer, including a first conductive structure disposed along the length direction of the substrate layer; and An insulating layer is disposed on the side of the conductive layer away from the substrate layer, and the projection surface of the insulating layer on the substrate layer does not coincide with the projection surface of the positive electrode film layer on the substrate layer. The conductivity of the conductive layer is greater than that of the substrate layer.

2. The battery cell according to claim 1, characterized in that, The substrate layer has a width dimension of W1 mm. The first conductive structure includes N conductive strips, which are non-overlapping along the width of the substrate layer, where N is a positive integer greater than or equal to 1, and the sum of the dimensions of the N conductive strips along the width of the substrate layer is W² mm. Among them, W1 / W2 is in the range of 5 to 100.

3. The battery cell according to claim 2, characterized in that, in, 3≤W2≤15, can be replaced by 9≤W2≤13.

4. The battery cell according to claim 2 or 3, characterized in that, The N conductive strips have the same width.

5. The battery cell according to any one of claims 2 to 4, characterized in that, When N is greater than or equal to 2, the N conductive strips are symmetrically distributed, wherein the projection surfaces of the first conductive strip and the Nth conductive strip on the substrate layer fall into the projection surface of the insulating layer on the substrate layer.

6. The battery cell according to any one of claims 2 to 4, characterized in that, When N is 1, the projection surface of the first conductive strip on the substrate layer falls into the projection surface of the insulating layer on the substrate layer.

7. The battery cell according to any one of claims 2 to 6, characterized in that, Along the width direction of the substrate layer, the closest distance between the outer periphery of the projection surface of the first conductive strip on the substrate layer and the outer periphery of the substrate layer is 25mm-35mm.

8. The battery cell according to any one of claims 1 to 7, characterized in that, The conductive layer further includes a second conductive structure, wherein the angle between the length direction of the second conductive structure and the length direction of the first conductive structure is between 10° and 170°, and the second conductive structure and the first conductive structure have an intersection point.

9. The battery cell according to any one of claims 1 to 8, characterized in that, The substrate layer has a thickness dimension of H1μm, where 8≤H1≤16, and can be optionally 10≤H1≤15.

10. The battery cell according to claim 9, characterized in that, The conductive layer has a dimension of H2μm along the thickness direction of the substrate layer, where H1:H2 = 0.25-0.

75.

11. The battery cell according to claim 9 or 10, characterized in that, The dimension of the insulating layer along the direction of the substrate layer is H3μm, where H1:H3=0.25-0.

6.

12. The battery cell according to claim 11, characterized in that, The positive electrode film has a thickness dimension of H4μm, where H2+H3 <H4。 13. The battery cell according to any one of claims 1 to 12, characterized in that, The conductivity of the conductive layer is in the range of 6*10. 7 -10 8 S / m.

14. The battery cell according to any one of claims 1 to 13, characterized in that, The conductive layer includes at least one of Al, Cu, Ni, Ag, Au, graphite, graphene, PANI, CNTs, RGO, SP, and EG.

15. The battery cell according to any one of claims 1 to 13, characterized in that, The insulating layer includes at least one of AT11, PET, PP, PI, AlN, Si3N4, and BN.

16. An electrical appliance, characterized in that, The electrical device includes a battery cell as described in any one of claims 1 to 15.

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