Battery cell and electronic device

Abstract

The application discloses a laminated battery cell and an electronic device, and belongs to the technical field of batteries. The disclosed electronic device comprises a laminated battery cell, which comprises: at least two negative electrode sheets, each negative electrode sheet is arranged in sequence along the thickness direction of the cell, and the negative electrode sheet comprises a negative electrode current collector and a negative electrode active layer which are stacked; the at least two negative electrode sheets comprise a first negative electrode sheet and a second negative electrode sheet, the thickness of the negative electrode current collector of the first negative electrode sheet is smaller than the thickness of the negative electrode current collector of the second negative electrode sheet, so that the thickness of the first negative electrode sheet is smaller than the thickness of the second negative electrode sheet; the negative electrode current collector of the first negative electrode sheet comprises a base layer and a conductive layer, the density of the base layer is smaller than the density of the conductive layer, so that the density of the first negative electrode sheet is smaller than the density of the second negative electrode sheet.

Description

Technical Field

[0001] This application belongs to the field of battery technology, specifically relating to a cell and electronic device for a stacked battery. Background Technology

[0002] Compared to wound batteries, stacked batteries are largely free from problems such as corner cracking and lithium plating at corners. As a result, stacked batteries are now commonly used in electronic devices.

[0003] However, the structural design of traditional stacked battery cells still has some shortcomings. Specifically, in related technologies, increasing the capacity of stacked battery cells requires increasing the thickness of the cells. However, increasing the cell thickness makes it difficult to adapt to the trend of thinner and lighter electronic devices. In other words, there is a contradiction between increasing the capacity of stacked battery cells and controlling the cell thickness. Related technologies cannot reduce the cell thickness while ensuring that the cell capacity of stacked batteries is not reduced. Summary of the Invention

[0004] The purpose of this application is to provide a battery cell and electronic device for a stacked battery, which can solve the problem in related technologies that it is difficult to reduce the thickness of the battery cell without reducing the capacity of the stacked battery cell.

[0005] In a first aspect, embodiments of this application provide a cell for a stacked battery, comprising: At least two negative electrode plates are arranged sequentially along the thickness direction of the battery cell. Each negative electrode plate includes a negative current collector and a negative active layer stacked together. The at least two negative electrode sheets include a first negative electrode sheet and a second negative electrode sheet, wherein the thickness of the negative electrode current collector of the first negative electrode sheet is less than the thickness of the negative electrode current collector of the second negative electrode sheet, so that the thickness of the first negative electrode sheet is less than the thickness of the second negative electrode sheet. The negative current collector of the first negative electrode sheet includes a base layer and a conductive layer, wherein the density of the base layer is less than the density of the conductive layer, so that the density of the first negative electrode sheet is less than the density of the second negative electrode sheet.

[0006] Secondly, embodiments of this application provide an electronic device, including a housing and a stacked battery, wherein the stacked battery is disposed in the inner cavity of the housing, and the stacked battery includes the battery cells described above.

[0007] In this embodiment, the cell of the stacked battery includes a negative electrode sheet, which comprises a negative current collector and a negative active layer stacked together. There are at least two negative electrode sheets, including a first negative electrode sheet and a second negative electrode sheet. The thickness of the negative current collector in the first negative electrode sheet is less than the thickness of the negative current collector in the second negative electrode sheet, so that the thickness of the first negative electrode sheet is less than the thickness of the second negative electrode sheet. In other words, this application can reduce the thickness of the negative current collector in some negative electrode sheets without reducing the thickness of the negative active layer, thereby reducing the total thickness of all negative electrode sheets and thus achieving a reduction in the thickness of the battery cell. The cell capacity mainly depends on the thickness of the negative active layer. In this configuration, the thickness of the negative active layer is not reduced; therefore, it achieves a reduction in the overall thickness of the battery cell while ensuring that the cell capacity is not significantly reduced.

[0008] Furthermore, the negative current collector of the first negative electrode includes a base layer and a conductive layer. The density of the base layer is less than the density of the conductive layer, so that the density of the first negative electrode is less than the density of the second negative electrode. Therefore, for the same volume, the weight of the first negative electrode is less than the weight of the second negative electrode. That is, this application can reduce the weight of some negative electrodes, thereby reducing the total weight of all negative electrodes, and thus reducing the weight of the battery cell. It is evident that the solution provided by the embodiments of this application not only compresses the thickness of the battery cell but also reduces its weight. The battery cell provided by the embodiments of this application can better meet the development needs of thinner and lighter electronic devices. Attached Figure Description

[0009] Figure 1 This is a schematic diagram of the negative electrode current collector of the first negative electrode sheet disclosed in the embodiments of this application; Figure 2 This is a schematic diagram of the structure of the first negative electrode sheet disclosed in the embodiments of this application; Figure 3 This is a schematic diagram of the structure of the second negative electrode sheet disclosed in the embodiments of this application; Figure 4 This is one of the structural schematic diagrams of the first positive electrode sheet disclosed in the embodiments of this application; Figure 5 This is a second schematic diagram of the structure of the first positive electrode sheet disclosed in the embodiments of this application; Figure 6 This is a schematic diagram of the structure of the second positive electrode sheet disclosed in an embodiment of this application; Figure 7 This is an exploded schematic diagram of the positive electrode, negative electrode, and separator disclosed in the embodiments of this application; Figure 8 This is a schematic diagram of the structure of the electronic device disclosed in the embodiments of this application.

[0010] Explanation of reference numerals in the attached figures: 100-Negative electrode sheet, 100a-First negative electrode sheet, 100b-Second negative electrode sheet, 110-Negative electrode current collector, 111-Base layer, 112-Conductive layer, 112a-First conductive layer, 112b-Second conductive layer, 120-Negative electrode active layer; 200-Positive electrode sheet, 200a-First positive electrode sheet, 200b-Second positive electrode sheet, 210-Positive current collector, 220-Positive active layer, 230-Safety coating; 300-diaphragm; 400 - Housing, 410 - Frame, 420 - Back cover. Detailed Implementation

[0011] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0012] The terms "first," "second," etc., used in the specification and claims of this application are used to distinguish similar objects and not to describe a specific order or sequence. It should be understood that such use of data can be interchanged where appropriate so that embodiments of this application can be implemented in orders other than those illustrated or described herein, and the objects distinguished by "first," "second," etc., are generally of the same class and the number of objects is not limited; for example, a first object can be one or more. Furthermore, in the specification and claims, "and / or" indicates at least one of the connected objects, and the character " / " generally indicates that the preceding and following objects are in an "or" relationship.

[0013] The following description, in conjunction with the accompanying drawings, details the battery cells and electronic devices of the stacked battery provided in this application through specific embodiments and application scenarios.

[0014] Please refer to Figures 1 to 7 As shown in the embodiment of this application, a cell for a stacked battery is provided, including at least two negative electrode sheets 100, the specific number of which depends on actual needs. Each negative electrode sheet 100 is arranged sequentially along the thickness direction of the cell. Each negative electrode sheet 100 includes a negative electrode current collector 110 and a negative electrode active layer 120 stacked together. The negative electrode current collector 110 serves as a substrate to support the negative electrode active layer 120. The negative electrode current collector 110 and the negative electrode active layer 120 are also arranged sequentially along the thickness direction of the cell, which is approximately [missing information - likely a specific orientation]. Figure 1 The direction indicated by arrow A in the diagram.

[0015] At least two negative electrode plates 100 include a first negative electrode plate 100a and a second negative electrode plate 100b. The thickness of the negative electrode current collector 110 of the first negative electrode plate 100a is less than the thickness of the negative electrode current collector 110 of the second negative electrode plate 100b, so that the thickness of the first negative electrode plate 100a is less than the thickness of the second negative electrode plate 100b.

[0016] The negative current collector 110 of the first negative electrode 100a includes a base layer 111 and a conductive layer 112. The base layer 111 and the conductive layer 112 are arranged sequentially along the thickness direction of the cell. The density of the base layer 111 is less than the density of the conductive layer 112, so that the density of the first negative electrode 100a is less than the density of the second negative electrode 100b. Here, density refers to the mass per unit volume. The density of the first negative electrode 100a is less than the density of the second negative electrode 100b, which means that the first negative electrode 100a weighs less for the same volume.

[0017] In this embodiment of the application, the cell of the stacked battery includes a negative electrode 100. The negative electrode 100 includes a negative current collector 110 and a negative active layer 120 stacked together. At least two negative electrode 100s are included, including a first negative electrode 100a and a second negative electrode 100b. The thickness of the negative current collector 110 of the first negative electrode 100a is less than the thickness of the negative current collector 110 of the second negative electrode 100b, so that the thickness of the first negative electrode 100a is less than the thickness of the second negative electrode 100b. That is to say, this application can reduce the thickness of the negative current collector 110 of part of the negative electrode 100 without reducing the thickness of the negative active layer 120, thereby reducing the total thickness of each negative electrode 100 and thus reducing the thickness of the cell. The cell capacity mainly depends on the thickness of the negative electrode active layer 120. Under this configuration, the thickness of the negative electrode active layer 120 is not reduced. Therefore, the overall thickness of the cell is reduced while ensuring that the cell capacity is not reduced.

[0018] Furthermore, the negative electrode current collector 110 of the first negative electrode 100a includes a base layer 111 and a conductive layer 112. The density of the base layer 111 is less than the density of the conductive layer 112, so that the density of the first negative electrode 100a is less than the density of the second negative electrode 100b. Therefore, for the same volume, the weight of the first negative electrode 100a is less than the weight of the second negative electrode 100b. That is, this application can reduce the weight of some of the negative electrode 100s, thereby reducing the total weight of all negative electrode 100s, and thus achieving a reduction in the weight of the battery cell. It is evident that the solution provided by the embodiments of this application not only compresses the thickness of the battery cell but also reduces its weight. The battery cell provided by the embodiments of this application can better meet the development needs of thinner and lighter electronic devices.

[0019] In one specific embodiment, the negative current collector 110 of the second negative electrode 100b is a one-piece structure, made entirely of the same material as the conductive layer 112 of the first negative electrode 100a. With this one-piece design, the negative current collector 110 of the second negative electrode 100b has better overall strength and a longer service life. Furthermore, in this embodiment, the uniform material of the negative current collector 110 of the second negative electrode 100b reduces its processing difficulty.

[0020] Specifically, the material of the negative current collector 110 of the second negative electrode 100b and the conductive layer 112 of the negative current collector 110 of the first negative electrode 100a is copper.

[0021] In another embodiment, in the thickness direction of the cell, the cell includes a first negative electrode assembly and a second negative electrode assembly arranged sequentially. Both the first negative electrode assembly and the second negative electrode assembly include a plurality of negative electrode sheets 100 arranged sequentially, and the negative electrode sheet 100 of the first negative electrode assembly is the first negative electrode sheet 100a, and the negative electrode sheet 100 of the second negative electrode assembly is the second negative electrode sheet 100b.

[0022] In this embodiment, each negative electrode 100 of the first negative electrode assembly is a first negative electrode 100a, resulting in a smaller overall thickness and weight of the first negative electrode assembly, and consequently, a smaller overall thickness and weight of the battery cell. Simultaneously, each negative electrode 100 of the second negative electrode assembly is a second negative electrode 100b, meaning that none of the negative electrode 100s in the second negative electrode assembly undergoes thinning or weight reduction treatment. This layout creates a continuous high-strength region for the second negative electrode assembly, effectively ensuring the mechanical safety of the battery cell. Furthermore, using the solution provided in this embodiment, the types of negative electrode 100 involved in both the first and second negative electrode assemblies are relatively few, thus reducing their processing difficulty.

[0023] For example, the structural parameters of each first negative electrode 100a in the first negative electrode assembly are identical. These structural parameters may include the thickness parameters of the base layer 111 and the conductive layer 112. This configuration results in high structural consistency among the first negative electrode 100a in the first negative electrode assembly, thereby reducing the processing difficulty of the first negative electrode assembly. Similarly, the structural parameters of each second negative electrode 100b in the second negative electrode assembly can also be identical, and will not be elaborated further here. Alternatively, the structural parameters of each first negative electrode 100a in the first negative electrode assembly and the structural parameters of each second negative electrode 100b in the second negative electrode assembly can also differ, depending on the actual design requirements.

[0024] For example, the battery cell only includes a first negative electrode assembly and a second negative electrode assembly, that is, all the negative electrode sheets 100 of the battery cell are divided into a first negative electrode assembly and a second negative electrode assembly. As a result, the types of negative electrode sheets 100 involved in the battery cell are fewer and the overall structure is simpler.

[0025] For example, the number of first negative electrode 100a in the first negative electrode assembly is less than or equal to 15, and the number of second negative electrode 100b in the second negative electrode assembly is less than or equal to 15.

[0026] In other embodiments, the first negative electrode assembly may include other types of negative electrode 100 besides the first negative electrode 100a. Similarly, the second negative electrode assembly may include other types of negative electrode 100 besides the second negative electrode 100b. Exemplarily, both the first and second negative electrode assemblies include both the first negative electrode 100a and the second negative electrode 100b, and the first negative electrode 100a and the second negative electrode 100b are arranged alternately along the thickness direction of the battery cell.

[0027] In another embodiment, reference Figure 1 As shown, the negative current collector 110 of the first negative electrode 100a includes at least two conductive layers 112, including a first conductive layer 112a and a second conductive layer 112b. A base layer 111 is located between the first conductive layer 112a and the second conductive layer 112b, and the thicknesses of the first conductive layer 112a and the second conductive layer 112b are equal. In this arrangement, the first conductive layer 112a, the base layer 111, and the second conductive layer 112b are arranged sequentially along the thickness direction of the battery cell.

[0028] In this embodiment, the first conductive layer 112a and the second conductive layer 112b have the same thickness, which helps to reduce the processing difficulty of the negative electrode current collector 110. In this layout, the first conductive layer 112a and the second conductive layer 112b are located on opposite sides of the base layer 111. On this basis, unifying the thickness of the first conductive layer 112a and the second conductive layer 112b is beneficial to balancing the forces on opposite sides of the base layer 111, which can extend the service life of the negative electrode current collector 110.

[0029] For example, the thickness of the base layer 111 ranges from 3μm to 6μm, and the thickness of the first conductive layer 112a and the second conductive layer 112b ranges from 2μm to 5μm.

[0030] In other embodiments, the thicknesses of the first conductive layer 112a and the second conductive layer 112b may also be unequal.

[0031] In another embodiment, the base layer 111 is a non-metallic layer. Exemplarily, the base layer 111 is a plastic layer, and more specifically, it can be a polyethylene terephthalate (PET) layer or a polypropylene (PP) layer. Compared to metallic materials, non-metallic materials generally have lower density and cost. Therefore, setting the base layer 111 as a non-metallic layer can effectively reduce the weight of the battery cell and lower its cost.

[0032] In other embodiments, the base layer 111 may also be a metal layer.

[0033] In another embodiment, reference Figures 3 to 5 As shown, the battery cell also includes at least two positive electrode plates 200, the specific number of which depends on actual needs. Each positive electrode plate 200 and each negative electrode plate 100 are arranged alternately in the thickness direction of the battery cell. Each positive electrode plate 200 includes a positive current collector 210 and a positive active layer 220. In the thickness direction of the battery cell, the positive current collector 210 has a first side and a second side facing away from each other, and the positive active layer 220 is stacked on both the first and second sides of the positive current collector 210.

[0034] At least two positive electrode sheets 200 include a first positive electrode sheet 200a and a second positive electrode sheet 200b. The positive current collector 210 of the first positive electrode sheet 200a is in contact with the positive active layer 220, or a safety coating 230 is provided between the positive current collector 210 of the first positive electrode sheet 200a and the positive active layer 220 located on its first side, or a safety coating 230 is provided between the positive current collector 210 of the first positive electrode sheet 200a and the positive active layer 220 located on its second side. The positive current collector 210 of the second positive electrode sheet 200b is provided with a safety coating 230 between it and the positive active layer 220 on its first side, and between it and the positive active layer 220 on its second side, so that the thickness of the first positive electrode sheet 200a is less than the thickness of the second positive electrode sheet 200b.

[0035] In this embodiment, the first positive electrode 200a may include a safety coating 230, or the safety coating 230 may be omitted. When the safety coating 230 is omitted, the positive current collector 210 of the first positive electrode 200a is in contact with the positive active layer 220. When the first positive electrode 200a includes a safety coating 230, the safety coating 230 is only disposed on one side of the positive current collector 210 of the first positive electrode 200a, i.e., the first side or the second side of the positive current collector 210. Meanwhile, the second positive electrode 200b has a safety coating 230 between its positive current collector 210 and the positive active layer 220 on its first side, as well as between its positive active layer 220 on its second side. That is, the second positive electrode 200b has a safety coating 230 on both opposite sides of its positive current collector 210, thereby achieving a thickness of less than that of the second positive electrode 200a. As can be seen, the solution in this embodiment reduces the thickness and weight of the positive electrode 200 by omitting the safety coating 230 on at least one side of the positive electrode 200, thereby further reducing the thickness and weight of the battery cell. Furthermore, the solution provided in this embodiment does not involve reducing the thickness of the positive current collector 210, thus ensuring the performance of the positive current collector 210.

[0036] Specifically, the positive current collector 210 can be an aluminum current collector, and in the cell thickness direction, adjacent positive electrode plates 200 and negative electrode plates 100 are separated by a separator 300, for example.

[0037] In other embodiments, the thickness of each positive electrode 200 may also be equal, that is, a safety coating 230 is provided on the first and second sides of the positive current collector 210 of each positive electrode 200. Alternatively, the thickness of the positive current collector 210 of the first positive electrode 200a may be reduced, thereby achieving a thickness of the first positive electrode 200a that is less than the thickness of the second positive electrode 200b.

[0038] In a further embodiment, in the thickness direction of the cell, the cell includes a first positive electrode assembly and a second positive electrode assembly arranged sequentially. Both the first positive electrode assembly and the second positive electrode assembly include a plurality of positive electrode sheets 200 arranged sequentially, and the positive electrode sheet 200 of the first positive electrode assembly is the first positive electrode sheet 200a, and the positive electrode sheet 200 of the second positive electrode assembly is the second positive electrode sheet 200b.

[0039] In this embodiment, each positive electrode 200 of the first positive electrode assembly is a first positive electrode 200a, resulting in a smaller overall thickness and weight of the first positive electrode assembly, and consequently, a smaller overall thickness and weight of the battery cell. Meanwhile, each positive electrode 200 of the second positive electrode assembly is a second positive electrode 200b, meaning that none of the positive electrodes 200 in the second positive electrode assembly undergoes thinning or weight reduction treatment. This layout creates a continuous, high-safety area for the second positive electrode assembly, effectively ensuring the mechanical safety of the battery cell. Furthermore, using the solution provided in this embodiment, the types of positive electrode 200 involved in both the first and second positive electrode assemblies are relatively few, thus reducing their processing difficulty.

[0040] For example, the structural parameters of each first positive electrode 200a in the first positive electrode assembly, such as the thickness parameter of the positive current collector 210, are consistent. This configuration results in high structural consistency among the first positive electrode 200a, thereby reducing the processing difficulty of the first positive electrode assembly. Similarly, the structural parameters of each second positive electrode 200b in the second positive electrode assembly can also be consistent, which will not be elaborated further here. Alternatively, the structural parameters of each first positive electrode 200a in the first positive electrode assembly and each second positive electrode 200b in the second positive electrode assembly can also differ, depending on actual design requirements.

[0041] For example, the battery cell only includes a first positive electrode assembly and a second positive electrode assembly, that is, all the positive electrode 200 of the battery cell are divided into a first positive electrode assembly and a second positive electrode assembly. As a result, the types of positive electrode 200 involved in the battery cell are fewer and the overall structure is simpler.

[0042] For example, the number of first positive electrode 200a in the first positive electrode assembly is less than or equal to 15, and the number of second positive electrode 200b in the second positive electrode assembly is less than or equal to 15.

[0043] In other embodiments, the first positive electrode assembly may include other types of positive electrode 200 besides the first positive electrode 200a. Similarly, the second positive electrode assembly may include other types of positive electrode 200 besides the second positive electrode 200b. Exemplarily, both the first and second positive electrode assemblies include both the first positive electrode 200a and the second positive electrode 200b, and the first positive electrode 200a and the second positive electrode 200b are arranged alternately along the thickness direction of the battery cell.

[0044] In another embodiment, the battery cell further includes at least two positive electrode plates 200, with each positive electrode plate 200 and each negative electrode plate 100 arranged alternately in the thickness direction of the battery cell. Each positive electrode plate 200 includes a positive current collector 210, a safety coating 230, and a positive active layer 220. In the thickness direction of the battery cell, the positive current collector 210 has a first side and a second side facing away from each other. The positive active layer 220 is stacked on both the first and second sides of the positive current collector 210. The safety coating 230 is disposed between the positive current collector 210 and the positive active layer 220, and is located on the first or second side of the positive current collector 210. In other words, the safety coating 230 is disposed on only one side of the positive current collector 210 of each positive electrode plate 200, i.e., the first or the second side.

[0045] Compared to the scheme in which a positive active layer 220 is provided on both the first and second sides of the positive current collector 210 of each positive electrode 200, in this embodiment, a safety coating 230 is provided only on one side of the positive current collector 210 of each positive electrode 200. The thickness of each positive electrode 200 is reduced, which can better reduce the thickness and weight of the battery cell.

[0046] This application also provides a stacked battery, which includes a protection board and the aforementioned battery cell. The battery cell includes both a positive electrode 200 and a negative electrode 100, both electrically connected to the protection board. The protection board provides protection, thereby reducing the occurrence of electrical faults and extending the battery cell's lifespan. This stacked battery includes the aforementioned battery cell and has the same beneficial effects as the aforementioned battery cell, which will not be repeated here.

[0047] Specifically, the positive electrode 200 can be provided with a positive tab, and the negative electrode 100 can be provided with a negative tab. The positive electrode 200 is electrically connected to the protection board through the positive tab, and the negative electrode 100 is electrically connected to the protection board through the negative tab.

[0048] This application also provides an electronic device, which includes a housing 400 and a stacked battery. The stacked battery is disposed within the inner cavity of the housing 400 and includes the battery cells described above. This electronic device includes the battery cells described above and has the same beneficial effects as the battery cells described above, which will not be repeated here. Additionally, exemplarily, the electronic device can be a smartphone, tablet computer, or e-book reader, etc.

[0049] In a further embodiment, reference is made to... Figure 8As shown, the housing 400 includes a frame 410 and a rear cover 420. The frame 410 and the rear cover 420 enclose the inner cavity of the housing 400. The battery cell includes a first negative electrode 100a and a second negative electrode 100b. The second negative electrode 100b is closer to the rear cover 420 than the first negative electrode 100a. The thickness of the second negative electrode 100b is greater than that of the first negative electrode 100a, and the second negative electrode 100b has better safety protection capabilities. By making the second negative electrode 100b closer to the rear cover 420 than the first negative electrode 100a, it can better adapt to scenarios where the safety protection requirements on the side of the battery cell closer to the rear cover 420 are higher than those on the side of the battery cell farther from the rear cover 420.

[0050] Optionally, the battery cell includes the first negative electrode assembly and the second negative electrode assembly mentioned above, with the second negative electrode assembly positioned closer to the back cover 420 than the first negative electrode assembly. This allows the area of ​​the battery cell near the back cover 420 to be a continuous area with high safety protection, which helps extend the battery cell's lifespan.

[0051] Optionally, a portion of the frame 410 is located on the side of the battery cell away from the back cover 420. The frame 410 is a metal structure, meaning that the portion of the frame 410 on the side of the battery cell away from the back cover 420 has high strength. Furthermore, a display screen is located on the side of the frame 410 away from the back cover 420, which can provide a certain degree of protection. Thus, the safety protection requirements for the side of the battery cell away from the back cover 420 are lower than those for the side of the battery cell closer to the back cover 420. On this basis, by making the second negative electrode 100b closer to the back cover 420 than the first negative electrode 100a, it helps to make the safety performance level of the entire electronic device more consistent in all directions, thereby extending the service life of the electronic device.

[0052] In other embodiments, the second negative electrode 100b may also be further away from the back cover 420 than the first negative electrode 100a.

[0053] In a further embodiment, the housing 400 includes a frame 410 and a rear cover 420, which together form the inner cavity of the housing 400. The battery cell includes a first positive electrode 200a and a second positive electrode 200b, with the second positive electrode 200b being closer to the rear cover 420 than the first positive electrode 200a. The thickness of the second positive electrode 200b is greater than that of the first positive electrode 200a, resulting in superior safety protection capabilities. By placing the second positive electrode 200b closer to the rear cover 420 than the first positive electrode 200a, it can also better adapt to scenarios where the safety protection requirements on the side of the battery cell closer to the rear cover 420 are higher than those on the side farther from the rear cover 420.

[0054] Optionally, the battery cell includes the first positive electrode assembly and the second positive electrode assembly mentioned above. The second positive electrode assembly is closer to the back cover 420 than the first positive electrode assembly. This also makes the area of ​​the battery cell close to the back cover 420 a continuous area with high safety protection, which helps to extend the service life of the battery cell.

[0055] Similarly, the frame 410 is located on the side of the battery cell away from the back cover 420. The frame 410 is a metal structure, meaning that the part of the frame 410 on the side of the battery cell away from the back cover 420 has high strength. In addition, the display screen is located on the side of the frame 410 away from the back cover 420, which can play a certain protective role. Therefore, the safety protection requirements of the side of the battery cell away from the back cover 420 are lower than those of the side of the battery cell closer to the back cover 420. On this basis, by making the second positive electrode 200b closer to the back cover 420 than the first positive electrode 200a, it also helps to make the safety performance level of the electronic device in all directions more consistent, which can extend the service life of the electronic device.

[0056] In other embodiments, the second positive electrode 200b may also be further away from the back cover 420 than the first positive electrode 200a.

[0057] In one optional embodiment, the electronic device includes a first positive electrode assembly, a second positive electrode assembly, a first negative electrode assembly, and a second negative electrode assembly. The second positive electrode assembly is closer to the back cover 420 than the first positive electrode assembly, and the second negative electrode assembly is also closer to the back cover 420 than the first negative electrode assembly. In this arrangement, the second positive electrode assembly and the second negative electrode assembly work together to ensure the safety protection capability of the part of the battery cell close to the back cover 420, thereby extending the service life of the battery cell.

[0058] In a further embodiment, the housing 400 includes a frame 410, which is a metal structure. The battery cell includes a positive electrode 200, which includes a positive current collector 210, a safety coating 230, and a positive active layer 220. In the thickness direction of the battery cell, the positive current collector 210 has a first side and a second side facing away from each other. The safety coating 230 is disposed between the positive current collector 210 and the positive active layer 220 and is located on the first side or the second side of the positive current collector 210.

[0059] In this embodiment, the frame 410 is a metal structure. As mentioned above, this configuration provides high strength and strong safety protection. Simultaneously, by placing the safety coating 230 between the positive current collector 210 and the positive active layer 220, and positioning it on either the first or second side of the positive current collector 210 (i.e., omitting the safety coating 230 on one side of the positive current collector 210 and only arranging it on one side), the strength of the frame 410 itself can compensate for the loss of safety protection performance caused by omitting part of the safety coating 230, thus ensuring the safety protection performance of the battery cell. Therefore, this achieves both a reduction in battery cell thickness and ensures the battery cell's lifespan.

[0060] The following describes in detail the battery cells provided in the embodiments of this application, using four specific examples and a comparative example: Comparative example: The battery cell includes multiple positive electrode plates 200 and multiple negative electrode plates 100, with more than 10 positive electrode plates 200 and more than 10 negative electrode plates 100. Each positive electrode plate 200 has a safety coating 230 on the first and second sides of the positive current collector 210. The thickness of the safety coating 230 is 1.5 μm. Each negative electrode plate 100 is a second negative electrode plate 100b. The thickness of the second negative electrode plate 100b is 10 μm, and the negative current collector 110 of the second negative electrode plate 100b is an integral structure made of copper.

[0061] Example 1: The battery cell includes multiple positive electrode plates 200 and multiple negative electrode plates 100, with more than 10 of each. All positive electrode plates 200 are divided into a first positive electrode assembly and a second positive electrode assembly, and all negative electrode plates 100 are divided into a first negative electrode assembly and a second negative electrode assembly. Specifically, the 10 positive electrode plates 200 furthest from the back cover 420 are all first positive electrode plates 200a and belong to the first positive electrode assembly, while the remaining positive electrode plates 200 are all second positive electrode plates 200b and belong to the second positive electrode assembly. Similarly, the 10 negative electrode plates 100 furthest from the back cover 420 are all first negative electrode plates 100a and belong to the first negative electrode assembly, while the remaining negative electrode plates 100 are all second negative electrode plates 100b and belong to the second negative electrode assembly. Furthermore, the first and second sides of the positive current collector 210 of the first positive electrode plate 200a are omitted. The first negative electrode 100a has a slightly safe coating 230. The base layer 111 of the negative electrode current collector 110 of the first negative electrode 100a is a PET layer, and the negative electrode current collector 110 of the first negative electrode 100a also includes a first conductive layer 112a and a second conductive layer 112b. The first conductive layer 112a and the second conductive layer 112b are both copper layers. The thickness of the base layer 111, the first conductive layer 112a and the second conductive layer 112b is 3μm. The negative electrode current collector 110 of the second negative electrode 100b is an integral structure and is made entirely of copper.

[0062] Compared with all the positive electrode sheets 200 in the comparative example, the total thickness of all the positive electrode sheets 200 in this embodiment is reduced by 30 μm, and the energy density (ED) of the cell can be increased by approximately 0.5% by adopting the arrangement of the positive electrode sheets 200 in this embodiment.

[0063] Compared with all the negative electrode sheets 100 in the comparative example, the total thickness of all the negative electrode sheets 100 in this embodiment is reduced by 10 μm, and by adopting the arrangement of the negative electrode sheets 100 in this embodiment, the ED of the cell can be improved by approximately 0.25%.

[0064] Using the solution provided in this embodiment, the battery cell weight can be reduced by approximately 2g.

[0065] Example 2: The main difference between this embodiment and Embodiment 1 is that a safety coating 230 is provided on one or the second side of the positive current collector 210 of the first positive electrode 200a, that is, the safety coating 230 is only provided on one side of the positive current collector 210 of the first positive electrode 200a.

[0066] Compared with all the positive electrode sheets 200 in the comparative example, the total thickness of all the positive electrode sheets 200 in this embodiment is reduced by 15μm, and by adopting the arrangement of the positive electrode sheets 200 in this embodiment, the ED of the cell can be improved by approximately 0.25%.

[0067] Using the solution provided in this embodiment, the battery cell weight can be reduced by approximately 2g.

[0068] Example 3: The main difference between this embodiment and Embodiment 1 is that the five negative electrode sheets 100 furthest from the back cover 420 are all first negative electrode sheets 100a, belonging to the first negative electrode assembly, and the remaining negative electrode sheets 100 are all second negative electrode sheets 100b, belonging to the second negative electrode assembly. Furthermore, the thickness of the base layer 111 of the first negative electrode sheet 100a is 3μm, and the thickness of the first conductive layer 112a and the second conductive layer 112b are both 2μm.

[0069] Compared with all the negative electrode sheets 100 in the comparative example, the total thickness of all the negative electrode sheets 100 in this embodiment is reduced by 15μm, and by adopting the arrangement of the negative electrode sheets 100 in this embodiment, the ED of the cell can be improved by approximately 0.3%.

[0070] Using the solution provided in this embodiment, the battery cell weight can be reduced by approximately 1.5g.

[0071] Example 4: The main difference between this embodiment and Embodiment 1 is that the positive current collector 210 of each positive electrode 200 is provided with a safety coating 230 only on the first or second side, that is, the safety coating 230 is arranged on only one side of all positive electrode 200.

[0072] Compared with all the positive electrode sheets 200 in the comparative example, the total thickness of all the positive electrode sheets 200 in this embodiment is reduced by 39 μm, and the ED of the cell can be improved by approximately 0.7% by using the positive electrode sheets 200 in this embodiment.

[0073] Using the solution provided in this embodiment, the battery cell weight can be reduced by approximately 2g.

[0074] In addition, the electronic device includes the frame 410 mentioned above, and the frame 410 is a metal structure. Meanwhile, the frame 410 is combined with the battery cells in the above embodiments one to four and the comparative example to obtain the experimental results in Table 1 below. Specifically, the capacity of the battery cell is 10Ah.

[0075] Table 1 shows the experimental results of cell assembly in the framework and Examples 1 to 4 and the comparative examples.

[0076] It should be noted that: in Table 1, Base1 represents the energy density baseline value of the comparative example, and Base2 represents the weight baseline value of the comparative example. The percentage increase in ED benefits recorded in Table 1 are all percentage increases relative to the energy density baseline value of the comparative example, and the weight reduction values ​​recorded in Table 1 are all weight reduction values ​​relative to the weight baseline value of the comparative example. In addition, taking the heavy object impact and foreign object compression results of Example 1 as examples, the heavy object impact result "10 / 10 Pass" in Example 1 means that 10 repeated tests were conducted and all 10 tests were passed. The foreign object compression result "9 / 10 Pass" in Example 1 means that 10 repeated tests were conducted and 9 tests were passed. The heavy object impact and foreign object compression results of other examples are similar and will not be repeated here.

[0077] As shown in Table 1, the results of heavy object impact and foreign object compression in Examples 1 to 4 are generally similar to those in the comparative example, indicating that the solutions adopted in Examples 1 to 4 also have good mechanical safety performance. Meanwhile, compared to the comparative example, Examples 1 to 4 achieve improvements in both energy density (ED) and weight reduction. That is, by adopting the solutions provided in this application, the energy density of the battery cell can be increased and its weight reduced, which is beneficial for achieving thinner and lighter electronic devices.

[0078] The embodiments of this application have been described above with reference to the accompanying drawings. However, this application is not limited to the specific embodiments described above. The specific embodiments described above are merely illustrative and not restrictive. Those skilled in the art can make many other forms under the guidance of this application without departing from the spirit and scope of the claims, and all of these forms are within the protection scope of this application.

Claims

1. A cell for a stacked battery, characterized in that, include: At least two negative electrode plates (100) are arranged sequentially along the thickness direction of the battery cell. Each negative electrode plate (100) includes a negative current collector (110) and a negative active layer (120) stacked together. The at least two negative electrode sheets (100) include a first negative electrode sheet (100a) and a second negative electrode sheet (100b), wherein the thickness of the negative electrode current collector (110) of the first negative electrode sheet (100a) is less than the thickness of the negative electrode current collector (110) of the second negative electrode sheet (100b), so that the thickness of the first negative electrode sheet (100a) is less than the thickness of the second negative electrode sheet (100b); The negative current collector (110) of the first negative electrode (100a) includes a base layer (111) and a conductive layer (112), wherein the density of the base layer (111) is less than the density of the conductive layer (112) so that the density of the first negative electrode (100a) is less than the density of the second negative electrode (100b).

2. The battery cell according to claim 1, characterized in that, In the thickness direction of the battery cell, the battery cell includes a first negative electrode assembly and a second negative electrode assembly arranged in sequence. Both the first negative electrode assembly and the second negative electrode assembly include a plurality of negative electrode sheets (100) arranged in sequence. The negative electrode sheet (100) of the first negative electrode assembly is the first negative electrode sheet (100a), and the negative electrode sheet (100) of the second negative electrode assembly is the second negative electrode sheet (100b).

3. The battery cell according to claim 1, characterized in that, The negative current collector (110) of the first negative electrode sheet (100a) includes at least two conductive layers (112), including a first conductive layer (112a) and a second conductive layer (112b), the base layer (111) is located between the first conductive layer (112a) and the second conductive layer (112b), and the first conductive layer (112a) and the second conductive layer (112b) have the same thickness; And / or, the base layer (111) is a non-metallic layer.

4. The battery cell according to claim 1, characterized in that, The battery cell further includes at least two positive electrode plates (200), each of the positive electrode plates (200) and each of the negative electrode plates (100) are arranged alternately in the thickness direction of the battery cell. Each positive electrode plate (200) includes a positive current collector (210) and a positive active layer (220). In the thickness direction of the battery cell, the positive current collector (210) has a first side and a second side opposite to each other, and the positive active layer (220) is stacked on both the first side and the second side of the positive current collector (210). The at least two positive electrode plates (200) include a first positive electrode plate (200a) and a second positive electrode plate (200b). The positive current collector (210) of the first positive electrode plate (200a) is in contact with the positive active layer (220), or a safety coating (230) is provided between the positive current collector (210) of the first positive electrode plate (200a) and the positive active layer (220) located on its first side, or the positive current collector of the first positive electrode plate (200a) is... A safety coating (230) is provided between the body (210) and the positive electrode active layer (220) located on its second side, and the safety coating (230) is provided between the positive electrode current collector (210) of the second positive electrode (200b) and the positive electrode active layer (220) on its first side, and between the positive electrode active layer (220) on its second side, so that the thickness of the first positive electrode (200a) is less than the thickness of the second positive electrode (200b).

5. The battery cell according to claim 4, characterized in that, In the thickness direction of the battery cell, the battery cell includes a first positive electrode assembly and a second positive electrode assembly arranged in sequence. Both the first positive electrode assembly and the second positive electrode assembly include a plurality of positive electrode sheets (200) arranged in sequence. The positive electrode sheet (200) of the first positive electrode assembly is the first positive electrode sheet (200a), and the positive electrode sheet (200) of the second positive electrode assembly is the second positive electrode sheet (200b).

6. The battery cell according to claim 1, characterized in that, The battery cell further includes at least two positive electrode plates (200), each of the positive electrode plates (200) and each of the negative electrode plates (100) are arranged alternately in the thickness direction of the battery cell. Each positive electrode plate (200) includes a positive current collector (210), a safety coating (230) and a positive active layer (220). In the thickness direction of the battery cell, the positive current collector (210) has a first side and a second side opposite to each other. The positive active layer (220) is stacked on both the first side and the second side of the positive current collector (210). The safety coating (230) is disposed between the positive current collector (210) and the positive active layer (220) and is located on the first side or the second side of the positive current collector (210).

7. An electronic device, characterized in that, It includes a housing (400) and a stacked battery, the stacked battery being disposed in the inner cavity of the housing (400), the stacked battery including the cell according to any one of claims 1-6.

8. The electronic device according to claim 7, characterized in that, The housing (400) includes a frame (410) and a back cover (420), the frame (410) and the back cover (420) enclose to form the inner cavity of the housing (400), and the battery cell includes a first negative electrode (100a) and a second negative electrode (100b), the second negative electrode (100b) being closer to the back cover (420) than the first negative electrode (100a).

9. The electronic device according to claim 7, characterized in that, The housing (400) includes a frame (410) and a back cover (420), the frame (410) and the back cover (420) enclose to form the inner cavity of the housing (400), and the battery cell includes a first positive electrode (200a) and a second positive electrode (200b), the second positive electrode (200b) being closer to the back cover (420) than the first positive electrode (200a).

10. The electronic device according to claim 7, characterized in that, The housing (400) includes a frame (410), which is a metal structure. The battery cell includes a positive electrode sheet (200), which includes a positive current collector (210), a safety coating (230), and a positive active layer (220). In the thickness direction of the battery cell, the positive current collector (210) has a first side and a second side opposite to each other. The safety coating (230) is disposed between the positive current collector (210) and the positive active layer (220) and is located on the first side or the second side of the positive current collector (210).

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