Battery cell, single battery and electric equipment

Abstract

The utility model provides a battery cell, a single battery and electric equipment, the battery cell has a first direction, a second direction and a third direction, the battery cell comprises two first electrode assemblies and a second electrode assembly, the number of the first electrode assemblies is two, and the second electrode assembly is located between the two first electrode assemblies in the third direction; wherein the first electrode assembly comprises a plurality of first negative plates, a plurality of first positive plates and a plurality of first diaphragms, and in the direction from the first electrode assembly to the second electrode assembly, the first negative plates are gradually increased in the second direction; the second electrode assembly comprises a plurality of second negative plates, a plurality of second positive plates and a plurality of second diaphragms, and the sizes of the second negative plates in the second direction are the same. The battery cell disclosed by the utility model has the advantages of being convenient to enter a shell, improving the safety and the battery capacity and the like.

Description

Technical Field

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

[0002] A battery cell is a type of battery construction method, characterized by its electrodes being thin sheets arranged in a stacked manner, unlike the structure of a wound battery cell. The basic structure of a battery cell consists of alternating positive and negative electrode sheets. The positive and negative electrode sheets are cut from complete electrode sheets through die-cutting and slitting. After hot pressing, the positive, separator, and negative electrodes are tightly bonded together, forming a layered, angular, square structure. Generally, stacked square batteries consist of two or four stacked cells assembled into a casing.

[0003] Compared to wound batteries, during the cell assembly process, the four outer edges of the assembled cell are easily bumped against the prisms of the square aluminum casing. Damaged areas are prone to poor coverage or short circuits, severely affecting the battery yield during assembly. Furthermore, under high energy density requirements, the electrolyte injection and retention rates of traditional stacked cell structures are affected, thus impacting the subsequent cycle life of the battery. Utility Model Content

[0004] One objective of this application is to provide a battery cell that can at least solve the technical problems of existing battery cells being easily bumped into the outer casing during insertion, and the four edges of the stacked core being easily damaged, leading to short circuits or poor coverage.

[0005] Another object of this application is to provide a single-cell battery including the aforementioned cell.

[0006] Another object of this application is to provide an electrical device including the aforementioned single battery cell.

[0007] To achieve the above objectives, this application provides the following technical solutions.

[0008] According to a first aspect embodiment of the present application, the battery cell has a first direction, a second direction, and a third direction. The battery cell includes: a first electrode assembly and a second electrode assembly. The number of first electrode assemblies is two sets. In the third direction, the second electrode assembly is located between the two sets of first electrode assemblies. The first electrode assembly includes a plurality of first negative electrode plates, a plurality of first positive electrode plates, and a plurality of first separators. The size of the first separator in the second direction is larger than the size of the first negative electrode plate in the second direction. The size of the first negative electrode plate in the second direction is larger than the size of the first positive electrode plates on both sides in the second direction. In the direction from the first electrode assembly to the second electrode assembly, the size of the first negative electrode plate in the second direction gradually increases. The second electrode assembly includes a plurality of second negative electrode plates, a plurality of second positive electrode plates, and a plurality of second separators. The size of the second separator in the second direction is larger than the size of the second negative electrode plate in the second direction. The size of the second negative electrode plate in the second direction is larger than the size of the second positive electrode plates on both sides in the second direction. The sizes of the second negative electrode plates in the second direction are the same.

[0009] Optionally, the dimension of the second electrode assembly in the third direction is H1, and the dimension of the cell in the third direction is H, where 5% ≤ H1 / H ≤ 15%.

[0010] Optionally, the first separator has a larger dimension in the first direction than the first negative electrode in the first direction, and the second separator has a larger dimension in the first direction than the second negative electrode in the first direction; and / or, the first separator and the second separator have the same shape.

[0011] Optionally, the plurality of first negative electrode sheets have the same size in a first direction; and / or, the plurality of second negative electrode sheets have the same size in a first direction; and / or, the first negative electrode sheet and the second negative electrode sheet have the same size in a first direction; and / or, the first positive electrode sheet and the second positive electrode sheet have the same size in a first direction.

[0012] Optionally, in the second direction of the battery cell, one end of the first negative electrode has a first edge, the other end of the first negative electrode has a second edge, the first edges of two adjacent first negative electrodes are flush, and the second edges of two adjacent first negative electrodes are staggered.

[0013] Optionally, in the second direction of the battery cell, one end of the first negative electrode has a first edge, the other end of the first negative electrode has a second edge, the first edges of two adjacent first negative electrodes are staggered, and the second edges of two adjacent first negative electrodes are staggered.

[0014] Optionally, in the second direction, the spacing between the first edges of two adjacent first negative electrode sheets is the same as the spacing between the second edges.

[0015] Optionally, in the third direction, the first electrode assembly includes N first negative electrode sheets, wherein the first negative electrode sheet closer to the second electrode assembly in two adjacent first negative electrode sheets is 0.3mm-0.5mm larger in size in the second direction than the first negative electrode sheet farther from the second electrode assembly; and / or, in the third direction, the first electrode assembly includes N first positive electrode sheets, wherein the first positive electrode sheet closer to the second electrode assembly in two adjacent first positive electrode sheets is 0.3mm-0.5mm larger in size in the second direction than the first positive electrode sheet farther from the second electrode assembly.

[0016] A single-cell battery according to a second aspect of this application includes: a housing having a receiving space; and a cell installed in the receiving space, wherein the cell is a cell according to any of the above descriptions.

[0017] The electrical device according to the third aspect of this application includes any of the single-cell batteries described above.

[0018] According to the embodiments of this application, the battery cell uses a first electrode assembly and a second electrode assembly in combination. The second electrode assembly is located between the two sets of first electrode assemblies. By setting the size variation of the electrode plates of the first electrode assembly in the second direction, the probability of contact damage between the battery cell and the edge of the casing is reduced, while the space for storing electrolyte is increased, thereby increasing the electrolyte storage capacity and wetting effect.

[0019] Other features and advantages of this application will become clear from the following detailed description of exemplary embodiments with reference to the accompanying drawings. Attached Figure Description

[0020] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments of the present application and, together with their description, serve to explain the principles of the present application.

[0021] Figure 1 This is a schematic diagram of a positive electrode sheet according to an embodiment of this application;

[0022] Figure 2 This is a schematic diagram of a negative electrode sheet according to an embodiment of this application;

[0023] Figure 3 This is a schematic diagram of the structure of a second electrode assembly according to an embodiment of this application;

[0024] Figure 4This is a schematic diagram of the first positive electrode stack in a first electrode assembly according to an embodiment of this application;

[0025] Figure 5 This is a schematic diagram of the stacking of the first negative electrode in the first electrode assembly according to an embodiment of this application;

[0026] Figure 6 This is an internal schematic diagram of a single-cell battery according to an embodiment of this application;

[0027] Figure 7 This is a schematic diagram showing the distribution of the first negative electrode sheet of the first electrode assembly according to yet another embodiment of this application;

[0028] Figure 8 This is a schematic diagram showing the distribution of two first electrode assemblies and one second electrode assembly according to an embodiment of this application;

[0029] Figure 9 This is a schematic diagram showing the distribution of the first and second negative electrode plates according to an embodiment of this application;

[0030] Figure 10 This is a schematic diagram showing the distribution of the first and second positive electrode plates according to an embodiment of this application.

[0031] Attached icon number

[0032] 100 for a single cell;

[0033] 10 cells;

[0034] First electrode assembly 11; first negative electrode 111; first positive electrode 112; first diaphragm 113;

[0035] Second electrode assembly 12; Second negative electrode 121; Second positive electrode 122; Second diaphragm 123;

[0036] 13 foil; 14 tabs;

[0037] Casing 20. Detailed Implementation

[0038] Various exemplary embodiments of the present application will now be described in detail with reference to the accompanying drawings. It should be noted that, unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the present application.

[0039] The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the scope of this application and its application or use.

[0040] Techniques, methods, and equipment known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and equipment should be considered part of the specification.

[0041] In all the examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0042] It should be noted that similar labels and letters in the following figures indicate similar items; therefore, once an item is defined in one figure, it does not need to be discussed further in subsequent figures.

[0043] The battery cell 10 according to an embodiment of this application is described in detail below with reference to the accompanying drawings.

[0044] like Figures 1 to 6 As shown, the battery cell 10 according to an embodiment of this application has a first direction, a second direction and a third direction, and the battery cell 10 includes a first electrode assembly 11 and a second electrode assembly 12.

[0045] Specifically, the battery cell 10 has a first direction, a second direction, and a third direction. The battery cell 10 includes a first electrode assembly 11 and a second electrode assembly 12. There are two sets of first electrode assemblies 11. In the third direction, the second electrode assembly 12 is located between the two sets of first electrode assemblies 11. The first electrode assembly 11 includes a plurality of first negative electrode plates 111, a plurality of first positive electrode plates 112, and a plurality of first separators 113. The size of the first separator 113 in the second direction is larger than the size of the first negative electrode plate 111 in the second direction. The size of the first negative electrode plate 111 in the second direction is larger than the size of the first positive electrode plates 112 on both sides. The size of the positive electrode 112 in the second direction gradually increases in the direction from the first electrode assembly 11 to the second electrode assembly 12. The second electrode assembly 12 includes a plurality of second negative electrode 121, a plurality of second positive electrode 122 and a plurality of second separators 123. The size of the second separator 123 in the second direction is larger than the size of the second negative electrode 121 in the second direction. The size of the second negative electrode 121 in the second direction is larger than the size of the second positive electrode 122 on both sides in the second direction. The size of the second negative electrode 121 in the second direction is the same.

[0046] In other words, the battery cell 10 according to the embodiments of this application has a first direction, a second direction, and a third direction. Optionally, any two of the first direction, the second direction, and the third direction can be perpendicular to each other. For example, the first direction is the length direction, the second direction is the width direction, and the third direction is the thickness direction; or the first direction is the width direction, the second direction is the length direction, and the third direction is the thickness direction; or, for example, the first direction is the Z-axis direction, the second direction is the X-axis direction, and the third direction is the Y-axis direction. The battery cell 10 includes electrodes and separators, specifically including multiple positive electrodes, multiple separators, and multiple negative electrodes stacked in the third direction. The multiple positive electrodes can be divided into first positive electrodes 112 and second positive electrodes 122, the multiple negative electrodes can be divided into first negative electrodes 111 and second negative electrodes 121, and the multiple separators are divided into first separators 113 and second separators 123. Furthermore, no tabs are provided on the edge of the electrode extending along the first direction, tabs are provided on the edge of the electrode extending along the second direction, and the multiple electrodes are stacked along the third direction.

[0047] Specifically, the first positive electrode 112, the first separator 113, and the first negative electrode 111 constitute the first electrode assembly 11, and the second positive electrode 122, the second separator 123, and the second negative electrode 121 constitute the second electrode assembly 12. That is, the battery cell 10 is mainly composed of the first electrode assembly 11 and the second electrode assembly 12. There are two sets of first electrode assemblies 11, and the second electrode assembly 12 is sandwiched between the two sets of first electrode assemblies 11. Figure 6 As shown, the first electrode assembly 11, the second electrode assembly 12, and the first electrode assembly 11 are stacked along the Y-axis direction, which is also the third direction of the battery cell 10. It can be seen that in the third direction, the two outermost parts of the battery cell 10 are both first electrode assemblies 11, that is, the first electrode assembly 11 is used at the beginning and end of the stack in the Y-axis direction, and the second electrode assembly 12 is used at the middle position of the stack in the Y-axis direction.

[0048] The first electrode assembly 11 and the second electrode assembly 12 are illustrated below with examples.

[0049] (1) Regarding the first electrode assembly 11

[0050] like Figures 4 to 6As shown, in the Y-axis direction, the first separator 113 is disposed on the outermost side of the cell 10. From the outside to the inside, the first positive electrode 112, the first separator 113, and the first negative electrode 111 are stacked and staggered. The size of the first separator 113 in the X-axis direction is larger than that of the first negative electrode 111 in the X-axis direction. The size of the first negative electrode 111 in the X-axis direction is larger than that of the first positive electrode 112 on both sides of the first negative electrode 111 in the X-axis direction. This ensures that the two ends of the first negative electrode 111 completely cover the first positive electrode 112 on both sides in the X-axis direction, preventing sodium / lithium deposition during battery cycling.

[0051] As can be seen, the positive electrode plates in the first electrode assembly 11 are stacked as follows: Figure 4 As shown, the negative electrode plates are stacked as follows Figure 5 As shown, the dimensions of the electrode in the first electrode assembly 11 can change gradually in the second direction. It should be noted that because the dimensions of the electrode gradually change in the second direction, a non-right-angled region can be formed at at least one end in the second direction. Whether there is also a gradient change in dimensions in the first direction is not limited to this application; all such variations fall within the scope of protection of this application.

[0052] (2) Regarding the second electrode assembly 12

[0053] like Figure 3 As shown, in the Y-axis direction, the second positive electrode 122, the second separator 123, and the second negative electrode 121 are stacked and staggered. The second separator 123 has a larger dimension in the second direction than the second negative electrode 121, and the second negative electrode 121 has a larger dimension in the second direction than the second positive electrode 122 on both sides of it. This ensures that the second negative electrode 121 completely covers the second positive electrode 122 on both sides in the second direction, preventing sodium / lithium deposition during battery cycling. The dimensions of the second positive electrode 122 and the second negative electrode 121 in the second direction can be fixed.

[0054] Furthermore, a second electrode assembly 12 is disposed between two sets of first electrode assemblies 11. The first electrode assembly 11 of the battery cell 10 has a size gradient on both sides in the second direction, so that the two outer edges of at least one side of the battery cell 10 in the second direction present a certain gradient angle. For example, the two outer edges on the upper right and lower right sides of the battery cell 10 present a certain gradient angle.

[0055] When the battery cell 10 of the embodiments of this application is installed into the housing 20 to assemble a single battery cell 100, the end of the battery cell 10 in the X direction can be close to the housing 20, for example, close to the large surface of the housing 10. That is, the size of the electrode sheet on the battery cell 10 close to the large surface of the housing 20 has a gradient change in the second direction. This can solve the technical problems that the battery cell is easy to bump into the housing when it is inserted into the housing, and the four edges of the stacked core are easily damaged, resulting in short circuits or poor coverage. For example, the areas of the battery cell 10 close to the housing 10 at both ends in the X direction are designed with a predetermined number of layers of size gradient in the second direction, so that the four outer edges of the battery cell 10 in the X direction all have a certain gradient angle, reducing the probability of contact with the outer edges of the housing 20.

[0056] Therefore, according to the embodiments of this application, the battery cell 10, by employing a first electrode assembly 11 and a second electrode assembly 12 in combination, with the second electrode assembly 12 located between the two sets of first electrode assemblies 11, reduces the probability of contact damage between the battery cell 10 and the edge of the housing 20 by setting the size of the electrode sheet of the first electrode assembly 11 in the second direction, while increasing the space for storing electrolyte, increasing the electrolyte storage capacity and wetting effect.

[0057] According to one embodiment of this application, such as Figure 6 As shown, the dimension of the second electrode assembly 12 in the third direction is H1, and the dimension of the battery cell 10 in the third direction is H, where 5% ≤ H1 / H ≤ 15%. For example, the dimension of the battery cell 10 in the Y-axis direction is defined as H; the dimension of the second electrode assembly 12 in the Y-axis direction is defined as H1, where 5% ≤ H1 / H ≤ 15%. For example, the ratio of H1 / H can be 5%, 6%, 8%, 10%, 12%, 13%, or 15%, etc. This allows the battery cell 10 to form a core-like R-angle on at least one side in the second direction, preventing it from colliding with the housing 20 and causing failure when inserted into the housing.

[0058] Optionally, the shapes of the positive and negative electrode sheets in the embodiments of this application are as follows: Figure 1 and Figure 2 As shown, the electrode may include a foil 13, an active coating, and tabs 14. The active coating is applied to the foil 13, and the tabs 14 are connected to the empty foil area. The positive electrode uses aluminum foil, on which an active material is coated. The active material can be a layered oxide, a Prussian blue-based material, or a polyanionic compound; preferably, a layered oxide. The negative electrode uses aluminum or copper foil, preferably aluminum foil due to its lower cost; a hard carbon material is coated on the aluminum foil as an active coating.

[0059] According to one embodiment of this application, the first diaphragm 113 is larger in size in the first direction than the first negative electrode 111 in the first direction, and the second diaphragm 123 is larger in size in the first direction than the second negative electrode 121 in the first direction, which enables the diaphragm to cover the electrode in the first direction, thereby further improving safety.

[0060] In some specific embodiments of this application, the first diaphragm 113 and the second diaphragm 123 have the same shape, which facilitates fabrication and core stacking.

[0061] According to one embodiment of this application, a plurality of first negative electrode sheets 111 have the same dimensions in a first direction, that is, in a third direction, the upper first negative electrode sheet 111 has the same dimensions in the first direction as the lower first negative electrode sheet 111; and / or, a plurality of second negative electrode sheets 121 have the same dimensions in a first direction, that is, in a third direction, the upper second negative electrode sheet 121 has the same dimensions in the first direction as the lower second negative electrode sheet 121. In this embodiment, by using first negative electrode sheets 111 or second negative electrode sheets 121 with the same dimensions in the first direction, it is convenient to manufacture and to manufacture a regularly shaped single cell 100.

[0062] In some specific embodiments of this application, the first negative electrode 111 and the second negative electrode 121 have the same dimensions in the first direction; and / or, the first positive electrode 112 and the second positive electrode 122 have the same dimensions in the first direction, which facilitates manufacturing and facilitates the manufacturing of a regular-shaped single cell 100.

[0063] According to one embodiment of this application, such as Figure 7 As shown, in the second direction of the battery cell 10, one end of the first negative electrode 111 has a first edge, and the other end of the first negative electrode 111 has a second edge. The first edges of two adjacent first negative electrode 111 are flush, and the second edges of two adjacent first negative electrode 111 are staggered. That is, on one side of the second direction of the battery cell 10, one end of the plurality of first negative electrode 111 is flush, and on the other side of the second direction of the battery cell 10, the other ends of the plurality of first negative electrode 111 have a spacing in the second direction. For example, in the X direction, the left ends of the plurality of first negative electrode 111 on the left side of the battery cell 10 are flush, and because the plurality of first negative electrode 111 have different dimensions in the X direction, the right ends of the plurality of first negative electrode 111 are staggered and have a stepped shape.

[0064] In some specific embodiments of this application, such as Figures 8 to 10As shown, in the second direction of the battery cell 10, one end of the first negative electrode 111 has a first edge, and the other end of the first negative electrode 111 has a second edge. The first edges of two adjacent first negative electrode 111s are staggered, and the second edges of two adjacent first negative electrode 111s are staggered. That is, on both sides of the battery cell 10 in the second direction, the two ends of the plurality of first negative electrode 111s have a distance in the second direction. For example, in the X direction, the left ends of the plurality of first negative electrode 111s on the left side of the battery cell 10 are staggered, and the right ends of the plurality of first negative electrode 111s on the right side of the battery cell 10 are staggered, so the left and right ends of the plurality of first negative electrode 111s are both stepped. In this embodiment, when the battery cell 10 is installed in the housing 20, the four outer edges of the housing 20 face the gradient region of the battery cell 10, reducing the chance of edge-to-edge contact. In other words, along the thickness of the cell 10, the area of ​​the electrode gradually decreases near the start and end positions of the cell 10, enabling the cell 10 to form a gradually changing arc-shaped structure at both ends in the X direction. Simultaneously, the internal space of the casing 20 is increased, enhancing the liquid storage capacity and wetting effect.

[0065] In some specific embodiments of this application, in the second direction, the distance between the first edges of two adjacent first negative electrode plates 111 is the same as the distance between their second edges. That is, the distance between the first edge of the preceding first negative electrode plate 111 and the first edge of the following first negative electrode plate 111 is the same as the positional difference between the second edge of the preceding first negative electrode plate 111 and the second edge of the following first negative electrode plate 111, thus forming a symmetrical structure in the second direction, which facilitates the processing and fabrication of symmetrically shaped battery cells 10.

[0066] According to one embodiment of this application, in a third-party direction, the first electrode assembly 11 includes N first negative electrode sheets 111, wherein the first negative electrode sheet 111 closer to the second electrode assembly 12 in any two adjacent first negative electrode sheets 111 is 0.3mm-0.5mm larger in a second direction than the first negative electrode sheet 111 farther from the second electrode assembly 12; and / or, in a third-party direction, the first electrode assembly 11 includes N first positive electrode sheets 112, wherein the first positive electrode sheet 112 closer to the second electrode assembly 12 in any two adjacent first positive electrode sheets 112 is 0.3mm-0.5mm larger in a second direction than the first positive electrode sheet 112 farther from the second electrode assembly 12. For ease of explanation, the Nth first negative electrode sheet 111 can be labeled as the first negative electrode sheet 111 in the drawings. n The (N-1)th first negative electrode 111 is attached Figure 9 The first negative electrode plate 111 is marked in the middle. n-1 Similarly, the first negative electrode 111 is labeled as the first negative electrode 1111 in the attached drawing. Likewise, the Nth positive electrode 112 can also be labeled as the first negative electrode 1111 in the attached drawing. Figure 10The first positive electrode plate 112 is marked in the middle. N The (N-1)th first positive electrode 112 is marked as the first positive electrode 112 in the attached figure. N-1 Similarly, the first positive electrode 112 is marked as the first positive electrode 1121 in the attached figure.

[0067] The size difference between the Nth first positive electrode 112 and the (N-1)th first positive electrode 112 in the second direction is in the range of 0.3mm-0.5mm; and / or, the size reduction of the two outermost adjacent first positive electrode 112 in the second direction is in the range of 0.3mm-0.5mm, for example, the size reduction in the second direction is successively 0.3mm, 0.31mm, 0.33mm, 0.35mm, 0.38mm, 0.41mm, 0.43mm, 0.45mm, 0.48mm or 0.5mm, etc.

[0068] For example, in the third direction, the size of the two outermost adjacent first negative electrode sheets 111 of the first electrode assembly 11 is reduced by 0.3mm-0.5mm in the second direction, for example, by 0.3mm, 0.31mm, 0.33mm, 0.35mm, 0.38mm, 0.41mm, 0.43mm, 0.45mm, 0.48mm, or 0.5mm, respectively. As another example, the size of the two adjacent first negative electrode sheets 111 or the two adjacent first positive electrode sheets 112 of the outermost 6 to 8 layers of the first electrode assembly 11 is reduced by 0.3mm-0.5mm in the second direction.

[0069] In this embodiment, by limiting the size reduction range of the two adjacent first negative electrode plates 111 or the two adjacent first positive electrode plates 112 in the second direction to 0.3mm-0.5mm, the negative electrode coverage and high design capacity can be guaranteed while the size gradient changes in the second direction.

[0070] This application also provides a single-cell battery 100, which includes a casing 20 and a cell 10. The casing 20 has a receiving space, and the cell 10 is installed in the receiving space. The cell 10 is any of the cell 10 described in the above embodiments. Since the single-cell battery 100 of this application includes a cell 10, and the cell 10 has advantages such as easy insertion into the casing, less susceptibility to damage, and increased cell capacity, the battery 100 of this application also has the same advantages, which will not be elaborated here.

[0071] This application also provides an electrical device that includes a single battery 100 from any of the above embodiments. Since the single battery 100 of this application has advantages such as high safety and large capacity, the electrical device of this application also has the same advantages, which will not be elaborated upon here.

[0072] While specific embodiments of this application have been described in detail by way of examples, those skilled in the art should understand that the above examples are for illustrative purposes only and are not intended to limit the scope of this application. Those skilled in the art should understand that modifications can be made to the above embodiments without departing from the scope and spirit of this application. The scope of this application is defined by the appended claims.

Claims

1. A battery cell (10), characterized in that, The battery cell (10) has a first direction, a second direction, and a third direction, and the battery cell (10) includes: The first electrode assembly (11) and the second electrode assembly (12) are provided. The number of the first electrode assemblies (11) is two sets. In the third direction, the second electrode assembly (12) is located between the two sets of the first electrode assemblies (11). The first electrode assembly (11) includes a plurality of first negative electrode plates (111), a plurality of first positive electrode plates (112), and a plurality of first separators (113). The size of the first separator (113) in the second direction is larger than that of the first negative electrode plate (111) in the second direction. The size of the first negative electrode plate (111) in the second direction is larger than that of the first positive electrode plates (112) on both sides in the second direction. In the direction from the first electrode assembly (11) to the second electrode assembly (12), the size of the first negative electrode plate (111) in the second direction gradually increases. The second electrode assembly (12) includes a plurality of second negative electrode plates (121), a plurality of second positive electrode plates (122) and a plurality of second separators (123). The size of the second separator (123) in the second direction is larger than the size of the second negative electrode plate (121) in the second direction. The size of the second negative electrode plate (121) in the second direction is larger than the size of the second positive electrode plates (122) on both sides in the second direction. The size of the second negative electrode plate (121) in the second direction is the same.

2. The battery cell (10) according to claim 1, characterized in that, The second electrode assembly (12) has a dimension of H1 in the third direction, and the cell (10) has a dimension of H in the third direction, with 5% ≤ H1 / H ≤ 15%.

3. The battery cell (10) according to claim 1, characterized in that, The size of the first separator (113) in the first direction is larger than the size of the first negative electrode (111) in the first direction, and the size of the second separator (123) in the first direction is larger than the size of the second negative electrode (121) in the first direction; And / or, the first diaphragm (113) and the second diaphragm (123) have the same shape.

4. The battery cell (10) according to claim 1, characterized in that, Multiple first negative electrode plates (111) have the same size in a first direction; and / or, Multiple second negative electrode plates (121) have the same size in the first direction; and / or, The first negative electrode (111) and the second negative electrode (121) have the same dimensions in the first direction; and / or, The first positive electrode (112) and the second positive electrode (122) have the same dimensions in the first direction.

5. The battery cell (10) according to claim 1, characterized in that, In the second direction of the cell (10), one end of the first negative electrode (111) has a first edge, the other end of the first negative electrode (111) has a second edge, the first edges of two adjacent first negative electrodes (111) are flush, and the second edges of two adjacent first negative electrodes (111) are staggered.

6. The battery cell (10) according to claim 1, characterized in that, In the second direction of the cell (10), one end of the first negative electrode (111) has a first edge, the other end of the first negative electrode (111) has a second edge, the first edges of two adjacent first negative electrode (111) are staggered, and the second edges of two adjacent first negative electrode (111) are staggered.

7. The battery cell (10) according to claim 6, characterized in that, In the second direction, the spacing between the first edges of two adjacent first negative electrode plates (111) is the same as the spacing between the second edges.

8. The battery cell (10) according to claim 1, characterized in that, In the third direction, the first electrode assembly (11) includes N first negative electrode sheets (111), wherein the first negative electrode sheet (111) closer to the second electrode assembly (12) in two adjacent first negative electrode sheets (111) is 0.3mm-0.5mm larger in size in the second direction than the first negative electrode sheet (111) farther from the second electrode assembly (12); and / or, In the third direction, the first electrode assembly (11) includes N first positive electrode plates (112), and the first positive electrode plate (112) closer to the second electrode assembly (12) in two adjacent first positive electrode plates (112) is 0.3mm-0.5mm larger in size in the second direction than the first positive electrode plate (112) farther away from the second electrode assembly (12).

9. A single-cell battery (100), characterized in that, include: The housing (20) has a receiving space; A battery cell (10) is installed in the receiving space, and the battery cell (10) is a battery cell (10) according to any one of claims 1-8.

10. An electrical appliance, characterized in that, Includes the single cell battery (100) as described in claim 9.

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