An electrode, a battery, a battery assembly, and an electric device

Abstract

The application discloses a pole core, a battery, a battery assembly and an electric device. The pole core comprises a first electrode assembly, a second electrode assembly and a first negative plate arranged between the first electrode assembly and the second electrode assembly in a first direction. The first negative plate comprises a first current collector, and the first current collector comprises a first surface and a second surface opposite to each other in a thickness direction. The first surface is provided with a first negative active material layer, and the second surface is provided with a second negative active material layer. Thus, the first negative plate is used for transition at the joint position of the first electrode assembly and the second electrode assembly with different sizes. As long as the orthographic projection of the first positive active material layer is within the orthographic projection of the first negative active material layer, and the orthographic projection of the second positive active material layer is within the orthographic projection of the second negative active material layer, lithium precipitation can be avoided, the production process is facilitated, and the allowable deviation range of the production size of the first negative plate is improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, and more specifically, to a core, a battery, a battery assembly, and an electrical device. Background Technology

[0002] With societal development, various portable electronic devices have emerged. To improve the battery life of these devices, researchers often need to find ways to increase the energy density of lithium-ion batteries or make full use of the battery compartment space. While striving to maintain the slim profile of electronic products for optimal user experience, researchers also try to condense components such as circuit boards to free up more battery compartment space. This often results in battery compartments that are not perfectly rectangular. To accommodate different battery compartment spaces, connectors are often used to fix electrode cores of different shapes and sizes into a single, integrated core. Therefore, developing an electrode core that can adapt to different battery compartment spaces without sacrificing energy density is of great significance. Utility Model Content

[0003] To address at least one problem existing in the prior art, this application provides a core, a battery, a battery assembly, and an electrical device.

[0004] This application provides a polar core, comprising:

[0005] A first electrode assembly and a second electrode assembly stacked along a first direction, and

[0006] The first negative electrode is stacked between the first electrode assembly and the second electrode assembly;

[0007] The first negative electrode sheet includes a first current collector, a first negative electrode active material layer, and a second negative electrode active material layer. The first current collector includes a first surface and a second surface that are opposite to each other along its thickness direction. The first surface is provided with the first negative electrode active material layer, and the second surface is provided with the second negative electrode active material layer.

[0008] The first electrode assembly includes a first positive electrode near the first negative electrode, and a first positive electrode active material layer is provided on the side of the first positive electrode near the first negative electrode.

[0009] The second electrode assembly includes a second positive electrode near the first negative electrode, and a second positive electrode active material layer is provided on the side of the second positive electrode near the first negative electrode;

[0010] The first negative electrode active material layer is disposed opposite to the first positive electrode active material layer, and the second negative electrode active material layer is disposed opposite to the second positive electrode active material layer;

[0011] Along the first direction, the orthographic projection of the first positive electrode active material layer is within the orthographic projection of the first negative electrode active material layer, and the orthographic projection of the second positive electrode active material layer is within the orthographic projection of the second negative electrode active material layer;

[0012] Along the first direction, the orthographic projection of the first negative electrode active material layer is within the orthographic projection of the second negative electrode active material layer, or the orthographic projections of the first negative electrode active material layer and the second negative electrode active material layer are at least partially offset.

[0013] In some embodiments, along the first direction, the orthographic projection of the first electrode assembly lies within the orthographic projection of the second electrode assembly.

[0014] In some embodiments, the first negative electrode active material layer includes a main body and a thinned portion, wherein the thickness of the thinned portion is less than the thickness of the main body;

[0015] Along the first direction, the orthographic projection of the first positive electrode active material layer is within the orthographic projection of the main body.

[0016] In some embodiments, the minimum distance between the circumferential edge of the orthographic projection of the first positive electrode active material layer and the circumferential edge of the orthographic projection of the main body along the first direction ranges from [0.2mm, 3mm].

[0017] In some embodiments, the minimum distance between the side of the thinned portion connected to the main body and the side of the thinned portion away from the main body is in the range of [1mm, 10mm].

[0018] In some embodiments, the first surface includes a coated area and an empty foil area, the first negative electrode active material layer is disposed in the coated area, and the empty foil area is provided with an insulating element.

[0019] In some embodiments, the first electrode assembly and / or the second electrode assembly includes a single-sided electrode sheet away from the first negative electrode sheet, wherein no active material is disposed on the side of the single-sided electrode sheet away from the first negative electrode sheet.

[0020] In some embodiments, both the first electrode assembly and the second electrode assembly include at least two positive electrode plates and negative electrode plates that are stacked in an alternating manner;

[0021] The positive electrode includes a first positive electrode and a second positive electrode;

[0022] The electrode core also includes a separator, which is disposed between the negative electrode, the first negative electrode and the positive electrode to isolate the negative electrode, the first negative electrode and the positive electrode.

[0023] In some embodiments, the separator includes multiple independent sub-separators, which are respectively disposed between the negative electrode, the first negative electrode, and the positive electrode.

[0024] In some embodiments, the diaphragm includes an isolation portion and a bending portion, with the two ends of the bending portion respectively connected to two isolation portions, and at least a portion of the isolation portion having its two ends respectively connected to two bending portions;

[0025] At least a portion of the isolation portion is disposed between the negative electrode and the positive electrode, and at least a portion of the isolation portion is disposed between the first negative electrode and the positive electrode.

[0026] In some embodiments, the separator includes a first separator disposed between the first positive electrode and the first negative electrode;

[0027] Along the first direction, the orthographic projection of the first negative electrode active material layer lies within the orthographic projection of the first diaphragm.

[0028] In some embodiments, the first negative electrode active material layer includes a main part and a thinned part, and the minimum distance between the circumferential edge of the orthographic projection of the side of the thinned part away from the main part and the orthographic projection of the first diaphragm along the first direction is in the range of [0.5mm, 3mm].

[0029] In some embodiments, along the first direction, the orthographic projection of the positive electrode is within the orthographic projection of the adjacent negative electrode.

[0030] This application also provides a battery, including the electrode core provided in this application, and a housing, wherein the housing has a receiving cavity, and the electrode core is disposed in the receiving cavity.

[0031] This application also provides a battery assembly, including the battery provided in this application.

[0032] This application also provides an electrical device, including the battery provided in this application, and / or the battery assembly provided in this application.

[0033] The electrode core of this application includes a first electrode assembly and a second electrode assembly stacked along a first direction, and a first negative electrode sheet disposed between the first electrode assembly and the second electrode assembly. The first negative electrode sheet includes a first current collector, which includes a first surface and a second surface opposite to each other along its thickness direction. The first surface is provided with a first negative electrode active material layer, and the second surface is provided with a second negative electrode active material layer. The first electrode assembly includes a first positive electrode sheet near the first negative electrode sheet, and the side of the first positive electrode sheet near the first negative electrode sheet is provided with a first positive electrode active material layer. The second electrode assembly includes a second positive electrode sheet near the first negative electrode sheet, and the second positive electrode sheet... A second positive electrode active material layer is provided on the side near the first negative electrode sheet; the first negative electrode active material layer is disposed opposite to the first positive electrode active material layer, and the second negative electrode active material layer is disposed opposite to the second positive electrode active material layer; along a first direction, the orthographic projection of the first positive electrode active material layer is within the orthographic projection of the first negative electrode active material layer, and the orthographic projection of the second positive electrode active material layer is within the orthographic projection of the second negative electrode active material layer; along the first direction, the orthographic projection of the first negative electrode active material layer is within the orthographic projection of the second negative electrode active material layer, or the orthographic projections of the first negative electrode active material layer and the second negative electrode active material layer are at least partially offset. Therefore, at the junction of first electrode assemblies and second electrode assemblies of different sizes, a first negative electrode sheet is used for transition, provided that the orthographic projections of the first positive electrode active material layer and the second positive electrode active material layer are both within the orthographic projections of the first negative electrode active material layer, thus avoiding lithium plating while providing convenience for the production process and improving the allowable deviation range of the first negative electrode sheet's production dimensions.

[0034] Additional aspects and advantages of embodiments of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of embodiments of this application. Attached Figure Description

[0035] The above and / or additional aspects and advantages of this application will become apparent and readily understood from the description of the embodiments taken in conjunction with the following drawings, wherein:

[0036] Figure 1 This is a cross-sectional structural diagram of the electrode core according to certain embodiments of this application;

[0037] Figure 2 This is a cross-sectional structural diagram of the electrode core according to certain embodiments of this application;

[0038] Figure 3 This is a cross-sectional structural diagram of the electrode core according to certain embodiments of this application;

[0039] Figure 4 This is a cross-sectional structural diagram of the electrode core according to certain embodiments of this application.

[0040] Explanation of key component symbols:

[0041] 1-First electrode assembly; 11-First positive electrode sheet; 111-First positive electrode active material layer;

[0042] 2-Second electrode assembly; 22-Second positive electrode sheet; 222-Second positive electrode active material layer;

[0043] 3-First negative electrode sheet; 31-First negative electrode active material layer; 32-Second negative electrode active material layer; 33-First current collector;

[0044] 4-Septum; 41-First septum; 42-Sub-septum; 401-Bend; 402-Isolation section. Detailed Implementation

[0045] The embodiments of this application are described in detail below. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain the embodiments of this application, and should not be construed as limiting the embodiments of this application.

[0046] In the current technology, with the development of society, various portable electronic devices have emerged. To improve the battery life of these devices, researchers often need to find ways to increase the energy density of lithium-ion batteries or make full use of the battery compartment space. While striving to maintain the thickness of electronic products for optimal user experience, researchers also try to condense components such as circuit boards to free up more battery compartment space. This often results in battery compartments that are not perfectly rectangular. To accommodate different battery compartment spaces, connectors are often used to fix electrode cores of different shapes and sizes into a single, integrated core. Therefore, developing an electrode core that can adapt to different battery compartment spaces without sacrificing energy density is of great significance.

[0047] To address at least one problem in the prior art, this patent proposes an electrode core, comprising a first electrode assembly and a second electrode assembly stacked along a first direction, and a first negative electrode sheet disposed between the first electrode assembly and the second electrode assembly. The first negative electrode sheet includes a first current collector, which includes a first surface and a second surface opposite to each other along its thickness direction. The first surface is provided with a first negative electrode active material layer, and the second surface is provided with a second negative electrode active material layer. The first electrode assembly includes a first positive electrode sheet near the first negative electrode sheet, and the side of the first positive electrode sheet near the first negative electrode sheet is provided with a first positive electrode active material layer. The second electrode assembly includes a first positive electrode sheet near the first negative electrode sheet. The second positive electrode has a second positive active material layer on its side closest to the first negative electrode. The first negative active material layer and the first positive active material layer are positioned opposite each other. Along a first direction, the orthographic projection of the first positive active material layer is within the orthographic projection of the first negative active material layer, and the orthographic projection of the second positive active material layer is also within the orthographic projection of the second negative active material layer. Alternatively, the orthographic projection of the first negative active material layer is within the orthographic projection of the second negative active material layer, or the orthographic projections of the first and second negative active material layers are at least partially offset. Therefore, by using the first negative electrode at the junction of first and second electrode assemblies of different sizes, as long as the orthographic projections of the first and second positive active material layers are both within the orthographic projections of the first and second positive active material layers, lithium plating can be avoided, facilitating the production process and improving the allowable deviation range of the first negative electrode's production dimensions.

[0048] The contents of this application will now be described in detail with reference to the accompanying drawings, so that those skilled in the art can have a clearer and more detailed understanding of the contents of this application.

[0049] Please refer to Figure 1 This patent proposes an electrode core 10, including a first electrode assembly 1 and a second electrode assembly 2 stacked along a first direction, and a first negative electrode sheet 3 disposed between the first electrode assembly 1 and the second electrode assembly 2. The first negative electrode sheet 3 includes a first current collector 33, which includes a first surface and a second surface opposite to each other along its thickness direction. The first surface is provided with a first negative electrode active material layer 31, and the second surface is provided with a second negative electrode active material layer 32. The first electrode assembly 1 includes a first positive electrode sheet 11 near the first negative electrode sheet 3, and the side of the first positive electrode sheet 11 near the first negative electrode sheet 3 is provided with a first positive electrode active material layer 111. The second electrode assembly 2 includes a second positive electrode sheet 22 near the first negative electrode sheet 3, and the side of the second positive electrode sheet 22 near the first negative electrode sheet 3 is provided with a second positive electrode active material layer 222.

[0050] The first negative electrode active material layer 31 is disposed opposite to the first positive electrode active material layer 111, and the second negative electrode active material layer 32 is disposed opposite to the second positive electrode active material layer 222; along the first direction, the orthogonal projection of the first positive electrode active material layer 111 is within the orthogonal projection of the first negative electrode active material layer 31, and the orthogonal projection of the second positive electrode active material layer 222 is within the orthogonal projection of the second negative electrode active material layer 32; along the first direction, the orthogonal projection of the first negative electrode active material layer 31 is within the orthogonal projection of the second negative electrode active material layer 32, or the orthogonal projection of the first negative electrode active material layer 31 and the orthogonal projection of the second negative electrode active material layer 32 are at least partially offset. Therefore, by using a first negative electrode 3 at the junction of the first electrode assembly 1 and the second electrode assembly 2 of different sizes, as long as the orthogonal projection of the first positive active material layer 111 is within the orthogonal projection of the first negative active material layer 31 and the orthogonal projection of the second positive active material layer 222 is within the orthogonal projection of the second negative active material layer 32, lithium plating can be avoided, while providing convenience for the production process and improving the allowable deviation range of the production size of the first negative electrode.

[0051] It should be noted that, unless otherwise specified in this application, all orthographic projections refer to orthographic projections along the first direction. If the orthographic projection in the text does not specify which direction it refers to, it refers to orthographic projections along the first direction.

[0052] The first direction is the stacking direction of the first electrode assembly 1, the first negative electrode 3, and the second electrode assembly 2. That is, the first direction is the thickness direction of the electrode involved in this application. For example, the first direction is also the thickness direction of the first negative electrode.

[0053] Specifically, when the orthogonal projection of the first negative electrode active material layer 31 in the first direction is within the orthogonal projection of the second negative electrode active material layer 32, the orthogonal projection of the first electrode assembly 1 is within the orthogonal projection of the second electrode assembly 2. At this time, the electrode core 10 is produced by stacking the first negative electrode sheet 3 between the first electrode assembly 1 and the second electrode assembly 2. As long as the orthogonal projection of the first positive electrode active material layer 111 is within the orthogonal projection of the first negative electrode active material layer 31 and the orthogonal projection of the second positive electrode active material layer 222 is within the second negative electrode active material layer 32 during production, lithium plating can be avoided.

[0054] When the orthographic projection of the first negative electrode active material layer 31 in the first direction and the orthographic projection of the second negative electrode active material layer 32 are at least partially misaligned, that is, the orthographic projection of the first electrode assembly 1 and the orthographic projection of the second electrode assembly 2 are at least partially misaligned, the electrode core has a special irregular shape, for example, it protrudes in different directions at different thicknesses of the electrode core. At this time, the first negative electrode sheet 3 can also serve as a transition between the first electrode assembly 1 and the second electrode assembly 2, which not only prevents lithium plating of the electrode core, but also provides convenience for the production process and improves the allowable deviation range of the production size of the first negative electrode sheet.

[0055] In some embodiments, the orthographic projection of the first electrode assembly 1 is within the orthographic projection of the second electrode assembly 2. In this case, the first negative electrode 3 is disposed between the first electrode assembly 1 and the second electrode assembly 2, which avoids lithium plating and provides convenience for the production process, thereby improving the allowable deviation range of the production size of the first negative electrode.

[0056] In some embodiments, the first negative electrode active material layer 31 includes a main portion 312 and a thinned portion 311, the thickness of which is less than the thickness of the main portion 312. The electrode sheet consists of a current collector and an active material layer coated on the surface of the current collector. When the first negative electrode active material layer 31 is coated on the first surface of the first current collector 33, since the active material is in a slurry state, a thinned portion 311 with a thickness less than the main portion 312 is generated at the edge of the main portion 312 during the coating process. By providing the thinned portion, the area of ​​the first negative electrode active material 31 can be increased through the thinned portion 311 generated during the coating process. This makes it easier for the first positive electrode active material layer 111 to be covered by the first negative electrode active material layer 31 during assembly, thereby preventing lithium plating on the first negative electrode sheet 3 and improving the quality of the electrode core 10.

[0057] It should be noted that the thinned portion 311 can be removed by other means, such as laser cleaning of the thinned portion 311, which can remove the thinned portion 311.

[0058] In some embodiments, the orthographic projection of the first positive electrode active material layer 111 lies within the orthographic projection of the main portion 312. (Reference) Figures 1-4 At this time, the orthographic projection of the first positive electrode active material layer 111 and the orthographic projection of the thinned portion 311 are completely misaligned, which avoids lithium plating caused by insufficient negative electrode active material volume in the thinned portion 311 when the thinned portion 311 and the first positive electrode active material layer 111 are opposite each other, thus improving the quality of the electrode core 10.

[0059] Furthermore, in some embodiments, the minimum distance between the circumferential edge of the orthographic projection of the first positive electrode active material layer 111 and the circumferential edge of the orthographic projection of the main body 312 is in the range of [0.2mm, 3mm]. That is, the first positive electrode active material layer 111 is completely opposite to the first negative electrode active material layer 31, and there is still a minimum distance between the edge of the first positive electrode active material layer 111 and the edge of the first negative electrode active material layer 31. At this time, lithium deposition on the first negative electrode sheet 3 can be avoided.

[0060] Furthermore, in order to prevent lithium plating in the thinned portion, the minimum distance between the side of the thinned portion 311 connected to the main portion 312 and the side of the thinned portion away from the main portion 312 is [1mm, 10mm]. At this time, the thinned portion 311 is set to have a certain width, which can prevent lithium plating in the thinned portion.

[0061] In some embodiments, the first surface includes a coated area and an empty foil area. The coated area is coated with a first negative electrode active material layer 31, while the empty foil area is not coated with active material. To prevent the current collector from curling due to the lack of material coating in the empty foil area, an inactive material layer can be coated on the empty foil area, such as by brushing on adhesive, or an adhesive can be provided in the empty foil area. That is, an insulating element can be provided in the empty foil area. The insulating element can be coated onto the empty foil area by coating or by bonding, etc. The insulating element can prevent the empty foil area from curling or peeling.

[0062] In some embodiments, reference Figures 1-4 The first electrode assembly 1 and / or the second electrode assembly 2 include a single-sided electrode 5 located away from the first negative electrode 3, see reference. Figure 1 The first electrode assembly 1 can be configured with an electrode 12 away from the first negative electrode 3 as a single-sided electrode 5. The electrode is composed of a current collector and a slurry coated on at least one side of the current collector in the thickness direction. That is, the surface of the electrode 12 away from the first negative electrode 3 is not coated with slurry. This makes it easier to assemble the battery core 10 after the first electrode assembly 1, the first negative electrode 3 and the second electrode assembly are stacked. If the side of the electrode 12 away from the first negative electrode 3 is coated with slurry, it is not only easy to come into contact with the battery casing, which may cause safety hazards, but also easy to contaminate the electrode core 10 during assembly due to contact with the slurry.

[0063] Similarly, refer to Figure 1 The electrode 23 of the second electrode assembly 2 that is away from the first negative electrode 3 can also be set as a single-sided electrode 5, that is, the surface of the electrode 23 away from the first negative electrode 3 is not coated with slurry. Therefore, after the first electrode assembly 1, the first negative electrode 3 and the second electrode assembly are stacked, it is more convenient to assemble the electrode core 10 into a battery. If the side of the electrode 23 away from the first negative electrode 3 is coated with slurry, it is not only easy to come into contact with the battery casing, which may cause safety hazards, but also easy to contaminate the electrode core 10 by contacting the slurry during assembly.

[0064] It should be noted that the electrode core 10 of this application may include multiple first electrode assemblies 1 and / or multiple second electrode assemblies 2, as well as multiple first negative electrode plates 3. For example, the electrode core 10 of this application may include two first electrode assemblies 1 and a first second electrode assembly 2, as well as two first negative electrode plates 3. The two first electrode assemblies 1 are respectively disposed on opposite sides of the second motor assembly 2 along a first direction, and the two first negative electrode plates 3 are respectively disposed between the two first electrode assemblies 1 and the second electrode assembly 2. In this case, the second electrode assembly 2 includes two second positive electrode plates 22 respectively close to the two first negative electrode plates 3, and the second electrode assembly 2 does not include a single-sided electrode plate 23.

[0065] In some embodiments, it may also include a first electrode assembly 1 and two second electrode assemblies 2, as well as two first negative electrode plates 3. In this case, the two second electrode assemblies 2 are respectively disposed on opposite sides of the first electrode assembly 1 along the first direction, and the two first negative electrode plates are respectively disposed between the two second electrode assemblies 2 and the first electrode assembly 1. In this case, the first electrode assembly includes two first positive electrode plates 11, and the two first positive electrode plates 11 are respectively disposed corresponding to the two first negative electrode plates 3. In this case, the first electrode assembly 1 does not include a single-sided electrode plate 12.

[0066] It should be noted that both the first electrode assembly 1 and the second electrode assembly 2 include at least two staggered positive and negative electrode plates. In the prior art, the positive electrode plate, separator 4, negative electrode plate, and positive electrode plate are typically stacked sequentially to form the electrode core. This stacking method is a common method for electrode cores and will not be elaborated further here. (Reference) Figure 1 The positive electrode includes a first positive electrode 11 and a second positive electrode 22. That is, all electrodes coated with positive active material in the electrode core 10 of this application are the positive electrode as referred to herein. The separator 4 is disposed between the positive electrode and the negative electrode, and also between the positive electrode and the first negative electrode 3. The separator 4 isolates the positive electrode and the negative electrode, preventing the positive active material and the negative active material from coming into contact and causing a chemical reaction, which could pose a safety risk to the battery.

[0067] It should be noted that, along the first direction, the orthogonal projection of the positive electrode will always fall within the orthogonal projection of the adjacent negative electrode. This is a basic requirement for setting the electrode core, and will not be elaborated further here.

[0068] In some embodiments, reference Figure 1 The separator 4 includes multiple independent sub-separators 42. Some sub-separators 42 are disposed between the positive electrode and the negative electrode, and some sub-separators 42 are disposed between the positive electrode and the first negative electrode 3. When stacking the positive electrode and the negative electrode, and when stacking the first electrode assembly 1, the first negative electrode 3, and the second electrode assembly 2, the sub-separators 42 are used to isolate the positive electrode active material and the negative electrode active material to ensure the safety of the electrode core 10 and prevent chemical reactions from occurring.

[0069] In some embodiments, the separator 4 includes a bending portion 401 and an isolation portion 402, meaning the separator can be a single unit. The bending portion 401 and the isolation portion 402 on a single separator achieve isolation between the positive and negative electrode active materials in the electrode core. By using a separator including the bending portion 401 and the isolation portion 402 to isolate the positive and negative electrode active materials, a better isolation effect can be achieved. Furthermore, the separator 4 does not need to be cut during production, reducing production steps and further lowering the production cost of the electrode core 10.

[0070] refer to Figures 2-4The two ends of the bending portion 401 are respectively connected to two isolation portions 402, and at least some of the isolation portions 402 are respectively connected to two bending portions 401. The two isolation portions 402 located at the beginning and end of the separator 4 are connected to a bending portion 401 at only one end, while the other ends of the two isolation portions 402 located at the beginning and end of the separator 4 are not connected to a bending portion 401. In this way, the separator 4 is divided into multiple isolation portions 402 by the bending portions 401. Some isolation portions 402 are located between the positive and negative electrode plates, and some isolation portions 402 are located between the first negative electrode plate and the positive electrode plate. The isolation of the positive and negative active materials in the electrode core can be achieved through a single separator 4, eliminating the need to cut the separator 4 into multiple parts and improving production efficiency.

[0071] Meanwhile, the bending portion 401 can wrap around the electrode sheet at the head of the electrode core, that is, the bending portion 401 can better isolate the positive electrode sheet and the negative electrode sheet. As a result, the diaphragm 4 with the bending portion 401 has a better isolation effect, further improving the safety and reliability of the electrode core.

[0072] It should be noted that the separator in the electrode core 10 can also simultaneously contain a sub-separator 42 and a separator 4 including a bending portion 401 and an isolation portion 402. For example, the positive electrode and the negative electrode in the first electrode assembly are separated by the bending portion 401 and the isolation portion 402, that is, the first electrode assembly 1 includes a separator 4. The positive electrode and the negative electrode in the second electrode assembly 2 are separated by the bending portion 401 and the isolation portion 402, that is, the second electrode assembly 2 also includes a separator 4. When the first electrode assembly 1, the first negative electrode 3, and the second electrode assembly 2 are stacked, the sub-separator 42 is used to place between the first electrode assembly and the first negative electrode 3, and between the first negative electrode 3 and the second electrode assembly 2, respectively. At this time, the electrode core 10 includes two independent separators 4 with bending portions 401 and isolation portions 402, and two sub-separators 42.

[0073] Therefore, no specific restrictions are placed on the number of separators 4 in the electrode core or the composition of the separators 4. Any separator 4 that can achieve the isolation between the positive electrode active material and the negative electrode material in the electrode core 10 is within the scope of protection of this application.

[0074] It should be noted that positive electrode active material refers to the active material coated on the current collector of the positive electrode sheet, and negative electrode active material refers to the active material coated on the current collector of the negative electrode sheet. Both of these active materials are well-known in the industry and are not specifically limited here.

[0075] It should be noted that the number of sub-diaphragms 42, or the number of bends 401 and isolation parts 402, is determined according to the number of positive and negative electrodes, and no specific restrictions are imposed here.

[0076] In some embodiments, for a diaphragm 4 with an isolation portion 402 and a bending portion 401, the length of the sub-diaphragm can be determined according to actual conditions. (See reference...) Figure 3 and Figure 4 The separator 402 can be set to be relatively long, thereby providing better isolation between the positive and negative electrode plates. Of course, to improve the energy density of the battery, typically, when setting the separator, the minimum distance between the circumferential edge of the separator's projected image and the circumferential edge of the electrode plate's projected image in the first direction should not be less than 0.5 mm. Since this dimensional setting is standard in the industry, it will not be elaborated further here.

[0077] It should be noted that in some embodiments, the separator 4 includes a first separator 41, which is disposed between the first positive electrode 11 and the first negative electrode 3. Since the first surface includes a coating area and an empty foil area, and the empty foil area does not actually have a corresponding positive electrode active material, a separator is not required on the empty foil area. That is, the first separator 41 does not need to completely cover the first current collector 33 when it is disposed. However, in order to avoid lithium deposition on the first negative electrode 3, the end of the first separator 41 near the thinning portion 311 needs to extend beyond the thinning portion 311 by a considerable amount. In other words, the minimum distance between the circumferential edge of the orthographic projection of the side of the thinning portion 311 away from the main portion 312 and the orthographic projection of the first separator 41 is in the range of [0.5mm, 3mm]. That is, compared with the coverage of traditional separators, the separator corresponding to the thinning section 311 needs to be larger in size. Specifically, the edge of the first separator 41 corresponding to the thinning section 311 needs to extend further beyond the edge of the thinning section 311 to ensure that the active material layer of the thinning section 311 is completely covered by the separator, so as to avoid the risk of lithium plating caused by the first negative electrode 3 due to powder shedding.

[0078] This application also provides a battery, which includes a casing and an electrode core. The casing has a receiving cavity, and the electrode core 10 is disposed in the receiving cavity. The electrode core provided by this application allows the battery to be made into irregular shapes, better adapting to electrical devices. Furthermore, the electrode core facilitates production and assembly, and better avoids lithium plating, thus improving the safety performance of the battery.

[0079] This application also provides a battery assembly, which includes at least one battery provided by this application. The battery assembly of this application can be a battery assembly composed of one battery and a protection board assembly, or it can be a battery assembly formed by electrically connecting multiple batteries provided by this application. Because the battery assembly of this application includes the battery of this application, its electrode core has a lower possibility of lithium plating, thus improving the reliability of the battery assembly of this application.

[0080] This application also provides an electrical device, which includes the battery provided in this application, and / or includes the battery module provided in this application. The electrical device of this application includes, but is not limited to, mobile phones, tablets, computers, etc. By using the electrode core of this application, the electrode core of the electrical device of this application is less prone to lithium deposition, thereby improving the reliability of the electrical device of this application.

[0081] In the description of this specification, the references to "certain embodiments," "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples" indicate that a specific feature, structure, material, or characteristic described in connection with an embodiment or example is included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0082] Although embodiments of this application have been shown and described above, it is understood that the above embodiments are exemplary and should not be construed as limiting this application. Those skilled in the art can make changes, modifications, substitutions and variations to the above embodiments within the scope of this application, the scope of which is defined by the claims and their equivalents.

Claims

1. An electrode core, characterized in that, include: A first electrode assembly and a second electrode assembly stacked along a first direction, and The first negative electrode is stacked between the first electrode assembly and the second electrode assembly; The first negative electrode sheet includes a first current collector, a first negative electrode active material layer, and a second negative electrode active material layer. The first current collector includes a first surface and a second surface that are opposite to each other along its thickness direction. The first surface is provided with the first negative electrode active material layer, and the second surface is provided with the second negative electrode active material layer. The first electrode assembly includes a first positive electrode near the first negative electrode, and a first positive electrode active material layer is provided on the side of the first positive electrode near the first negative electrode. The second electrode assembly includes a second positive electrode near the first negative electrode, and a second positive electrode active material layer is provided on the side of the second positive electrode near the first negative electrode; The first negative electrode active material layer is disposed opposite to the first positive electrode active material layer, and the second negative electrode active material layer is disposed opposite to the second positive electrode active material layer; Along the first direction, the orthographic projection of the first positive electrode active material layer is within the orthographic projection of the first negative electrode active material layer, and the orthographic projection of the second positive electrode active material layer is within the orthographic projection of the second negative electrode active material layer; Along the first direction, the orthographic projection of the first negative electrode active material layer is within the orthographic projection of the second negative electrode active material layer, or the orthographic projections of the first negative electrode active material layer and the second negative electrode active material layer are at least partially offset.

2. The electrode core according to claim 1, characterized in that, Along the first direction, the orthographic projection of the first electrode assembly lies within the orthographic projection of the second electrode assembly.

3. The electrode core according to claim 1, characterized in that, The first negative electrode active material layer includes a main part and a thinned part, wherein the thickness of the thinned part is less than the thickness of the main part; Along the first direction, the orthographic projection of the first positive electrode active material layer is within the orthographic projection of the main body.

4. The electrode core according to claim 3, characterized in that, Along the first direction, the minimum distance between the circumferential edge of the orthographic projection of the first positive electrode active material layer and the circumferential edge of the orthographic projection of the main body ranges from [0.2mm, 3mm].

5. The electrode core according to claim 3, characterized in that, The minimum distance between the side of the thinned portion connected to the main body and the side of the thinned portion away from the main body is in the range of [1mm, 10mm].

6. The electrode core according to claim 1, characterized in that, The first surface includes a coated area and an empty foil area, the first negative electrode active material layer is disposed in the coated area, and the empty foil area is provided with an insulating element.

7. The electrode core according to claim 1, characterized in that, The first electrode assembly and / or the second electrode assembly includes a single-sided electrode sheet away from the first negative electrode sheet, wherein no active material is disposed on the side of the single-sided electrode sheet away from the first negative electrode sheet.

8. The electrode core according to any one of claims 1-7, characterized in that, Both the first electrode assembly and the second electrode assembly include at least two staggered positive electrode plates and negative electrode plates; The positive electrode includes a first positive electrode and a second positive electrode; The electrode core also includes a separator, which is disposed between the negative electrode, the first negative electrode and the positive electrode to isolate the negative electrode, the first negative electrode and the positive electrode.

9. The electrode core according to claim 8, characterized in that, The separator includes multiple independent sub-separators, which are respectively disposed between the negative electrode, the first negative electrode, and the positive electrode.

10. The electrode core according to claim 8, characterized in that, The diaphragm includes an isolation portion and a bending portion, with two isolation portions respectively connected to the two ends of the bending portion, and at least a portion of the isolation portions having two bending portions respectively connected to the two ends of the bending portion. At least a portion of the isolation portion is disposed between the negative electrode and the positive electrode, and at least a portion of the isolation portion is disposed between the first negative electrode and the positive electrode.

11. The electrode core according to claim 8, characterized in that, The separator includes a first separator, which is disposed between the first positive electrode and the first negative electrode. Along the first direction, the orthographic projection of the first negative electrode active material layer lies within the orthographic projection of the first diaphragm.

12. The electrode core according to claim 11, characterized in that, The first negative electrode active material layer includes a main part and a thinned part. Along the first direction, the minimum distance between the orthographic projection of the side of the thinned part away from the main part and the orthographic projection of the first diaphragm is in the range of [0.5mm, 3mm].

13. The electrode core according to claim 8, characterized in that, Along the first direction, the orthographic projection of the positive electrode lies within the orthographic projection of the adjacent negative electrode.

14. A battery, characterized in that, The device includes the electrode core as described in any one of claims 1-13, and a housing, wherein the housing has a receiving cavity and the electrode core is disposed within the receiving cavity.

15. A battery assembly, characterized in that, Includes at least one battery as described in claim 14.

16. An electrical appliance, characterized in that, Includes the battery of claim 14, and / or the battery assembly of claim 15.

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