Battery cell and electric device

Abstract

The application provides a battery cell and an electric device. The battery cell comprises first and second pole pieces which are alternately stacked and are provided with a separation film. The first pole piece comprises a first current collector and a first active material layer provided on the first current collector, and the second pole piece comprises a second active material layer. The first active material layer comprises a main body portion and an end portion. The end portion is provided with a transition section which is recessed relative to the main body portion and a protruding structure which is protruded relative to the transition section. The transition section is adjacent to the main body portion and the protruding structure. In the length direction of the battery cell, the protruding structure is beyond the end portion of the second active material layer. In the circulation process of the battery cell, lithium is not easily deposited at the end portion of the first pole piece, and the performance of the battery cell is improved.

Description

Technical Field

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

[0002] A battery cell is a device that converts external energy into electrical energy and stores it internally to power external electronic devices (such as portable electronic devices) when needed. Currently, battery cells are widely used in devices such as drones, mobile phones, tablets, and laptops. Generally, a battery cell includes a first electrode, a separator, and a second electrode. The first electrode, separator, and second electrode are stacked, and the first and second electrodes have opposite polarities. Both the first and second electrodes include a current collector and an active material layer coated on the current collector. When coating the active material onto the current collector to form the active material layer, thinning at the ends of the active material layer is inevitable, which poses a risk of lithium plating at the electrode ends. Summary of the Invention

[0003] The present application aims to provide a battery cell and an electrical device to solve the problem in the prior art that, during the battery cell cycling process, as the electrolyte is continuously consumed, lithium plating easily forms at the ends of the active material layer of the electrode, which will cause the battery cell to bulge in this area, thereby causing the battery cell to fail.

[0004] According to one aspect of the present application, a battery cell is provided, including a first electrode, a second electrode, and a separator, wherein the first electrode and the second electrode are alternately stacked, and the separator is disposed between the first electrode and the second electrode; the first electrode includes a first current collector and a first active material layer disposed on the first current collector, the first active material layer including a main body portion and an end portion, the end portion having a transition section recessed relative to the main body portion and a protruding structure protruding relative to the transition section, the transition section being adjacent to the main body portion and the protruding structure; the second electrode includes a second active material layer; along the length direction of the battery cell, the protruding structure extends beyond the end portion of the second active material layer. Because the protruding structure extends beyond the end portion of the second active material layer, the thickness of the protruding structure can be set to be greater than the thickness of the main body portion of the first active material layer and less than any value of the distance between the first current collector and the second current collector, thereby improving the situation where, when the protruding structure corresponds to the end portion of the second active material layer, increasing the thickness of the protruding structure easily leads to the sum of the thickness of the protruding structure and the thickness of the second active material layer exceeding the distance between the first current collector and the second current collector, resulting in an increase in the end thickness of the battery cell.

[0005] Wherein, along the thickness direction of the battery cell, the distance from the lowest point of the transition section to the surface of the first current collector is hr, and the thickness of the main body of the first active material layer is ha, wherein (ha-hr) / ha≤2%. By limiting the transition section, during the battery cell cycling process, as the electrolyte is continuously consumed, the battery cell is less prone to lithium plating at the end of the first active material layer, that is, it is less prone to lithium plating in the thinned area of ​​the first electrode, resulting in excellent battery cell performance.

[0006] The surface of the transition section is the surface of the transition section that is far away from the first current collector.

[0007] The first current collector is provided with a first tab. The direction in which the first tab extends out of the first current collector is defined as the length direction of the battery cell. Along the length direction of the battery cell, the area within 10 mm from the edge of the first active material layer is defined as the end of the first active material layer.

[0008] The thickness direction of the battery cell is the direction in which the first and second electrodes are stacked.

[0009] The transition section is formed by a depression from the end of the first active material layer away from the surface of the first current collector toward the first current collector, and the lowest point of the transition section is the point corresponding to the maximum distance of the depression.

[0010] In one optional embodiment, the first current collector is provided with a first tab, and the direction in which the first tab extends out of the first current collector is defined as the length direction of the battery cell. Along the length direction of the battery cell, the distance from the lowest point of the transition section to the edge of the first active material layer is xr, where 2mm ≤ xr ≤ 4mm; the transition section has a point B, the distance from point B to the edge of the first active material layer is xb, xb-xr = 2mm; the distance from point B to the surface of the first current collector is hb, where (hb-hr) / (xb-xr) ≤ 2. The edge of the first active material layer is the end of the first active material layer away from the main body of the first active material layer. Point B on the transition section includes the point on the transition section farthest from the end of the first active material layer, i.e., point B on the transition section includes the end of the groove of the transition section closest to the main body of the first active material layer. By further defining the transition section, the appearance of deep and narrow recessed areas can be avoided.

[0011] In one alternative approach, the distance from the vertex of the surface of the protruding structure to the edge of the first active material layer along the length direction of the cell is xt, where 0.8mm ≤ xt ≤ 1.2mm.

[0012] The surface of the protruding structure is the surface of the protruding structure that is far away from the first current collector.

[0013] The vertex of the protruding structure is the point on the surface of the protruding structure that is farthest from the first current collector along the thickness direction of the battery cell.

[0014] In one alternative embodiment, the second electrode includes a second current collector and a second active material layer disposed on the second current collector; the ends of the first active material layer and the ends of the second active material layer are stacked. That is, along the thickness direction of the battery cell, the ends of the first active material layer and the ends of the second active material layer are overlapped; the overlap can be such that their edges are completely aligned, or their ends partially overlap, with the edges not aligned but substantially parallel.

[0015] In this configuration, the region within 10 mm from the edge of the second active material layer along the length of the battery cell is defined as the end of the second active material layer. In one optional configuration, the first current collector has a first tab, and the direction in which the first tab extends beyond the first current collector is defined as the length direction of the battery cell; along the length direction of the battery cell, the first active material layer extends beyond the second active material layer. The length direction of the battery cell is parallel to the first current collector; that is, the length direction of the battery cell is perpendicular to the thickness direction of the battery cell and parallel to the main plane of the battery cell. The main plane of the battery cell corresponds to the surface where the first and second electrodes are stacked.

[0016] In one alternative approach, along the length of the cell, the first active material layer extends beyond the second active material layer by a length ΔL, wherein 0.5mm ≤ ΔL ≤ 3mm.

[0017] In one alternative, the protrusion structure extends beyond the second active material layer along the length of the cell.

[0018] In one alternative approach, the perpendicular distance from any point on the edge of the protruding structure to the surface of the first current collector along the thickness direction of the battery cell is hp, and the thickness of the main body of the second active material layer is hc; wherein 0.9ha ≤ hp. The edge of the protruding structure along the thickness direction of the battery cell includes any point on the protruding structure away from the first current collector. By providing the protruding structure and defining the transition section, the active material at the end of the first active material layer is increased, making it less likely for lithium plating to occur in the thinned area of ​​the first electrode.

[0019] In one alternative embodiment, the vertical distance from the apex of the protrusion to the surface of the second current collector is Δhp, and the thickness of the main body of the second active material layer is hc, wherein Δhp ≥ 0.5hc, and the surface of the second current collector is the surface of the second current collector closest to the protrusion. Specifically, along the thickness direction of the battery cell, the apex of the protrusion is the point on the protrusion farthest from the first current collector. By defining the transition section and providing the protrusion, the risk of lithium plating at the end of the first active material layer of the battery cell is reduced. Furthermore, by limiting the vertical distance between the protrusion and the surface of the second current collector, the thickness of the battery cell at the protrusion is not increased.

[0020] In one alternative embodiment, the first current collector is provided with a first tab, and the direction in which the first tab extends out of the first current collector is defined as the length direction of the battery cell; along the length direction of the battery cell, the size of the separator extending beyond the first active material layer is not less than 1 mm.

[0021] In one alternative embodiment, the first current collector is provided with a first tab, and the first tab is not provided with the first active material layer beyond the surface of the first current collector.

[0022] In one alternative approach, the distance from the edge of the first active material layer to the edge of the first current collector is less than or equal to 1 mm.

[0023] In one optional embodiment, the first electrode is an anode electrode, and the first active material layer is an anode film; the second electrode is a cathode electrode, and the second active material layer is a cathode film.

[0024] In one optional embodiment, the first electrode is a cathode electrode, and the first active material layer is a cathode film; the second electrode is an anode electrode, and the second active material layer is an anode film.

[0025] According to one aspect of the embodiments of this application, an electrical device is provided, including a load and a battery cell as described in any of the above, the battery cell being used to supply power to the load.

[0026] The beneficial effect of this application embodiment is that it provides a battery cell and an electrical device. Since the protrusion structure extends beyond the end of the second active material layer, the thickness of the protrusion structure can be set to be greater than the thickness of the main body of the first active material layer and less than any value of the distance between the first current collector and the second current collector. This improves the situation where, when the protrusion structure corresponds to the end of the second active material layer, increasing the thickness of the protrusion structure easily causes the sum of the thickness of the protrusion structure and the thickness of the second active material layer to be greater than the distance between the first current collector and the second current collector, resulting in an increase in the end thickness of the battery cell. Attached Figure Description

[0027] One or more embodiments are illustrated by way of example with reference numerals in the accompanying drawings. These illustrations do not constitute a limitation on the embodiments. Elements with the same reference numerals in the drawings are denoted as similar elements. Unless otherwise stated, the figures in the drawings are not to be limited by scale.

[0028] Figure 1 This is a schematic diagram of the battery cell provided in an embodiment of this application;

[0029] Figure 2 This is provided by the embodiments of this application. Figure 1 A cross-sectional view of the PP line in the middle;

[0030] Figure 3 This is provided by the embodiments of this application. Figure 2 Enlarged view of section A1;

[0031] Figure 4 This is provided by the embodiments of this application. Figure 2 Enlarged view of section A2;

[0032] Figure 5 A schematic diagram of one orientation of the battery cell provided in this application embodiment;

[0033] Figure 6 The embodiments provided in this application Figure 2 Another schematic representation of the enlarged view of section A2;

[0034] Figure 7 This is a cross-sectional schematic diagram of another implementation of the battery cell provided in the embodiments of this application;

[0035] Figure 8 This is a cross-sectional schematic diagram of another implementation of the battery cell provided in the embodiments of this application;

[0036] Figure 9 This is a cross-sectional schematic diagram of another implementation of the battery cell provided in the embodiments of this application;

[0037] Figure 10 This is a cross-sectional schematic diagram of another implementation of the battery cell provided in the embodiments of this application. Detailed Implementation

[0038] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. It should be understood that the specific embodiments described herein are only used to explain this application and are not intended to limit this application. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0039] It should be noted that when an element is described as "fixed to" another element, it can be directly on the other element, or one or more intermediate elements may exist between them. When an element is described as "connected to" another element, it can be directly connected to the other element, or one or more intermediate elements may exist between them. The terms "vertical," "horizontal," "left," "right," and similar expressions used in this specification are for illustrative purposes only.

[0040] Furthermore, the technical features involved in the various embodiments of this application described below can be combined with each other as long as they do not conflict with each other.

[0041] Please see Figure 1 and Figure 2 The battery cell 100 includes a first electrode 1, a second electrode 2, and a separator 3. The first electrode 1 and the second electrode 2 are stacked alternately, and the separator 3 is disposed between the first electrode 1 and the second electrode 2.

[0042] For the first electrode 1 and the second electrode 2 mentioned above, please refer to... Figure 2 , Figure 3 and Figure 4 The first electrode 1 includes a first current collector 11 and a first active material layer 12, with the first active material layer 12 disposed on the first current collector 11. The second electrode 2 includes a second current collector 21 and a second active material layer 22, with the second active material layer 22 disposed on the second current collector 21.

[0043] When the first active material layer 12 is formed on the first current collector 11, an end portion 121 and a main body portion 122 of the first active material layer 12 are formed. The end portion 121 of the first active material layer 12 of the first electrode 1 has a transition section 1211 and a protrusion structure 1212. The transition section 1211 is adjacent to the main body portion 122 of the first active material layer 12 and the protrusion structure 1212. Along the thickness direction D1 of the cell 100, the distance from the lowest point of the surface of the transition section 1211 to the surface of the first current collector 11 is hr, and the thickness of the main body portion 122 of the first active material layer 12 is ha, where (ha-hr) / ha≤2%. In this application, because the transition section 1211 has a small depth and the end 121 of the first active material layer 12 has a protruding structure 1212, during the cycle of the cell 100, as the electrolyte is continuously consumed, the cell 100 is not prone to lithium plating at the end 121 of the first active material layer 12, that is, it is not prone to lithium plating in the thinned area of ​​the first electrode 1, and the cell 100 has excellent performance.

[0044] It is worth noting that the portion of the main body 122 of the first active material layer 12 near the edge of the protruding structure 1212, and the portion between the protruding structure 1212 and the edge of the main body 122 of the first active material layer 12, are all transition sections 1211.

[0045] The surface of the transition section 1211 is the surface of the transition section 1211 that is far away from the first current collector 11.

[0046] The thickness direction D1 of the cell 100 is the direction in which the first electrode 1 and the second electrode 2 are alternately stacked.

[0047] The first current collector 11 is provided with a first tab 4, and the direction in which the first tab 4 extends out of the first current collector 11 is defined as the length direction D2 of the battery cell 100. In some embodiments, the length direction D2 of the battery cell 100 is parallel to the first current collector 11 and perpendicular to the thickness direction D1 of the battery cell 100.

[0048] In some embodiments, the area within 10 mm from the edge of the first active material layer 12 along the length direction D2 of the cell 100 is the end 121 of the first active material layer 12.

[0049] The transition section 1211 is formed by recessing from the end 121 of the first active material layer 12 away from the surface of the first current collector 11 toward the first current collector 11.

[0050] The point at which the end 121 of the first active material layer 12 is far from the surface of the first current collector 11 and the point corresponding to the maximum distance towards the first current collector 11 is the lowest point of the surface of the transition section 1211.

[0051] The surface of the first current collector 11 is the surface on which the first active material layer 12 is disposed.

[0052] It should be noted that in some embodiments, the first tab 4 is located at the end 121 of the first current collector 11 near the first active material layer 12.

[0053] It should be noted that in some embodiments, the first electrode 4 and the first current collector 11 are integrally formed, or in other embodiments, the first electrode 4 is welded to the first current collector 11.

[0054] The main body 122 of the first active material layer 12 and the end 121 of the first active material layer 12 are connected. Along the thickness direction D1 of the cell 100, the thickness of the transition section 1211 of the end 121 of the first active material layer 12 is less than the thickness ha of the main body 122 of the first active material layer 12.

[0055] It should be noted that in some embodiments, the first current collector 11 includes a copper foil, and the formation process of the first electrode 1 is as follows: an active material is coated on the copper foil, and after the active material is formed, the copper foil and the active material are cut to form the first electrode 1. Since the copper foil is cut, generally, the end 121 of the first active material layer 12 is formed only at the end of the first current collector 11 near the first electrode tab 4.

[0056] The main body 222 of the second active material layer 22 is connected to the end 221 of the second active material layer 22. Along the thickness direction D1 of the cell 100, the thickness of the end 221 of the second active material layer 22 is less than the thickness hc of the main body 222 of the second active material layer 22.

[0057] In some embodiments, the end 221 of the second active material layer 22 is a thinned area that is naturally formed when the second active material layer 22 is formed. Along the length direction D2 of the battery cell 100, the size of the end 221 of the second active material layer 22 is related to the properties of the material forming the second active material layer 22. If the material forming the second active material layer 22 has good fluidity, the size of the end 221 of the second active material layer 22 is large along the second direction, and vice versa.

[0058] According to one embodiment of this application, along the length direction D2 of the cell 100, the area within 10 mm from the edge of the second active material layer 22 is the end 221 of the second active material layer 22.

[0059] When the first electrode 1 and the second electrode 2 are stacked, the ends 121 of the first active material layer 12 and the ends 221 of the second active material layer 22 are stacked. That is, along the thickness direction D1 of the cell 100, the ends 121 of the first active material layer 12 and the ends 221 of the second active material layer 22 overlap; the overlapping method can be that the edges of the two are completely aligned, or the ends 121 of the first active material layer 12 and the ends 221 of the second active material layer 22 partially overlap, and the edges of the ends 121 of the first active material layer 12 and the edges of the ends 221 of the second active material layer 22 are not aligned but are basically parallel.

[0060] It should be noted that in some embodiments, along the length direction D2 of the battery cell 100, the first active material layer 12 extends beyond the second active material layer 22.

[0061] It should be noted that, in some embodiments, along the length direction D2 of the battery cell 100, the length by which the first active material layer 12 extends beyond the second active material layer 22 is ΔL, wherein 0.5mm≤ΔL≤3mm.

[0062] It should be noted that in some embodiments, along the length direction D2 of the aforementioned cell 100, the first current collector 11 extends beyond the second current collector 12.

[0063] It should be noted that in some embodiments, along the length direction D2 of the aforementioned cell 100, the first current collector 11 extends beyond the second current collector 12 by a distance of not less than 0.5 mm and not more than 3 mm.

[0064] It should be noted that in some embodiments, along the length direction D2 of the aforementioned cell 100, the first electrode 1 extends beyond the second electrode 2.

[0065] It should be noted that in some embodiments, please refer to... Figure 4 Along the length direction D2 of the aforementioned cell 100, the first electrode 1 extends beyond the second electrode 2 by a dimension H1 of not less than 0.5 mm and not more than 3 mm.

[0066] It should be noted that in some embodiments, the distance from the edge of the first active material layer 12 to the edge of the first current collector 11 is less than or equal to 1 mm.

[0067] It should be noted that in some embodiments, the first current collector 11 is provided with a first tab 4, and the first tab 4 is not provided with a first active material layer 12 beyond the surface of the first current collector 11.

[0068] For the transition section 1211 mentioned above, please refer to Figure 2 , Figure 3 and Figure 4In some embodiments, the transition section 1211 is formed at the end 121 of the first active material layer 12 when the first active material layer 12 is formed on the first current collector 11. In the prior art, along the thickness direction D1 of the cell 100, the maximum depth of the formed transition section 1211 is generally 50% of the thickness ha of the main body 122 of the first active material layer 12. If the depth of the transition section 1211 is large, lithium plating is more likely to occur at the transition section 1211 of the cell 100.

[0069] The distance from the lowest point of the transition section 1211 to the surface of the first current collector 11 is hr, and the thickness of the main body 122 of the first active material layer 12 is ha, where (ha-hr) is the depth of the transition section 1211.

[0070] The depth of the transition section 1211 is the distance along the thickness direction D1 of the cell 100 from the end 121 of the first active material layer 12 away from the first current collector 11 and recessed towards the first current collector 11. In this application, (ha-hr) / ha≤2%, that is, the ratio of the depth of the transition section 1211 to the thickness of the main body 122 of the first active material layer 12 is less than 2%, indicating that the ratio of the farthest distance from the end 121 of the first active material layer 12 away from the first current collector 11 and recessed towards the first current collector 11 to the thickness of the main body 122 of the first active material layer 12 is less than 2%. In addition, the end 121 of the first active material layer 12 also has a protrusion structure 1212. By limiting the depth of the transition section 1211 to less than 2% of the thickness ha of the main body 122 of the first active material layer 12, and by providing the protrusion structure 1212, the active material at the end 121 of the first active material layer 12 is increased. The cell 100 is less likely to generate lithium plating at the transition section 1211, and the performance of the cell 100 is excellent.

[0071] It should be noted that you should refer to [link / reference]. Figure 2 , Figure 3 and Figure 6 In some embodiments, along the length direction D2 of the cell 100, the distance from the lowest point of the transition section 1211 to the edge of the first active material layer 12 is xr, where 2mm ≤ xr ≤ 4mm; the surface of the transition section 1211 has a point B, the distance from point B to the edge of the first active material layer 12 is xb, xb-xr = 2mm; the distance from point B to the surface of the first current collector 11 is hb; where (hb-hr) / (xb-xr) ≤ 2. By further defining the transition section 1211, the appearance of deep and narrow recesses can be avoided.

[0072] Wherein, the edge of the first active material layer 12 is the edge of the end 121 of the first active material layer 12 that is far away from the edge of the main body 122 of the first active material layer 12.

[0073] Wherein, along the length direction D2 of the cell 100, point B on the transition section 1211 includes the point on the transition section 1211 that is farthest from the end 121 of the first active material layer 12, that is, point B on the transition section 1211 includes one end of the groove of the transition section 1211 that is close to the main body 122 of the first active material layer 12.

[0074] It should be noted that you should refer to [link / reference]. Figure 7 In some embodiments, the transition section 1211 is partially filled with active material, making it less likely for lithium plating to occur at the transition section 1211, resulting in excellent performance of the cell 100.

[0075] It should be noted that you should refer to [link / reference]. Figure 8 In some embodiments, the distance hr from the lowest point of the surface of the transition section 1211 to the surface of the first current collector 11 is equal to the thickness ha of the main body 122 of the first active material layer 12, i.e., hr = ha. In other words, the end 121 of the first active material layer 12 is filled to the same thickness as the main body 122 of the first active material layer 12.

[0076] For the aforementioned protrusion structure 1212, please refer to [link / reference]. Figure 1 In some embodiments, along the length direction D2 of the cell 100, the protrusion structure 1212 extends beyond the end 221 of the second active material layer 22.

[0077] In some embodiments, along the length direction D2 of the cell 100, the length of the protrusion structure 1212 extending beyond the second active material layer 22 is not less than 0.5 mm and not more than 3 mm.

[0078] It is worth noting that, please refer to Figure 6 Along the length direction D2 of the cell 100, the distance from the vertex of the surface of the protrusion structure 1212 to the edge of the first active material layer 12 is xt, where 0.8mm≤xt≤1.2mm.

[0079] The surface of the protruding structure 1212 is the surface of the protruding structure 1212 that is away from the first current collector 11.

[0080] The vertex of the surface of the protrusion structure 1212 is the point on the surface of the protrusion structure 1212 that is farthest from the first current collector 11 along the thickness direction D1 of the cell 100.

[0081] It should be noted that you should refer to [link / reference]. Figure 1 and Figure 4In some embodiments, along the thickness direction D1 of the cell 100, the vertical distance from any point on the edge of the protrusion structure 1212 to the surface of the first current collector 11 is hp, and the thickness of the main body 222 of the second active material layer 22 is hc; wherein, 0.9ha ≤ hp. By providing the protrusion structure 1212 and defining the transition section 1211, during the cycling process of the cell 100, compared with the prior art cell 100, the active material at the end 121 of the first active material layer 12 is increased, so the cell 100 is less likely to generate lithium plating at the transition section 1211.

[0082] Wherein, along the thickness direction D1 of the cell 100, the edge of the protrusion structure 1212 includes any point of the protrusion structure 1212 away from the first current collector 11.

[0083] It should be noted that in some embodiments, please refer to... Figure 9 The vertical distance from the apex of the protrusion structure 1212 to the surface of the second current collector 21 is Δhp, and the thickness of the main body 222 of the second active material layer 22 is hc, wherein Δhp ≥ 0.5hc, and the surface of the second current collector 22 is the surface of the second current collector 22 close to the protrusion structure 1212. In this way, on the one hand, by setting the protrusion structure 1212 and defining the transition section 1211, the risk of lithium plating at the end 121 of the first active material layer 12 of the cell 100 is reduced, and on the other hand, by limiting the vertical distance between the protrusion structure 1212 and the surface of the second current collector 21, the thickness of the cell 100 at the protrusion structure 1212 is not increased.

[0084] Among them, along the thickness direction D1 of the cell 100, the vertex of the protrusion structure 1212 is the point of the protrusion structure 1212 that is farthest from the first current collector 11.

[0085] It should be noted that in some embodiments, please refer to... Figure 10 The end 221 of the second active material layer 22 of the second electrode 2 has a recessed region 2211, which is formed by recessing from the end 221 of the first active material layer 22 away from the surface of the second current collector 21 toward the second current collector 21.

[0086] For the aforementioned separator membrane 3, please refer to Figure 2 and Figure 4 The separator 3 is stacked between the first electrode 1 and the second electrode 2. In some embodiments, along the length direction D2 of the cell 100, the separator 3 extends beyond the first active material layer 12. It is understood that when the first active material layer 12 extends beyond the second active material layer 22, the separator 3 also extends beyond the second active material layer 22.

[0087] It should be noted that in some embodiments, along the length direction D2 of the cell 100, the separator 3 extends beyond the first active material layer 12 by a dimension of not less than 1 mm.

[0088] It should be noted that in some embodiments, the separator 3 extends beyond the first current collector 11 along the length direction D2 of the cell 100.

[0089] It should be noted that in some embodiments, along the length direction D2 of the cell 100, the separator 3 extends beyond the first current collector 11 by a dimension of not less than 1 mm.

[0090] It should be noted that in some embodiments, the separator 3 extends beyond the first electrode 1 along the length direction D2 of the cell 100.

[0091] It should be noted that you should refer to [link / reference]. Figure 4 In some embodiments, along the length direction D2 of the cell 100, the separator 3 extends beyond the dimension H2 of the first electrode 1 by not less than 1 mm.

[0092] In this embodiment, the battery cell 100 includes a first electrode 1, a second electrode 2, and a separator 3. The first electrode 1 and the second electrode 2 are stacked alternately, and the separator 3 is disposed between the first electrode 1 and the second electrode 2. The first electrode 1 includes a first current collector 11 and a first active material layer 12. The first active material layer 12 is disposed on the first current collector 11. The first active material layer 12 of the first electrode 1 includes a main body portion 122 and an end portion 121, wherein the end portion 121 has a transition section 1211 and a protrusion structure 1212, and the transition section 1211 is adjacent to the main body portion 122 and the protrusion structure 1212. Along the thickness direction D1 of the cell 100, the distance from the lowest point of the transition section 1211 to the surface of the first current collector 11 is hr, and the thickness of the main body 122 of the first active material layer 12 is ha. Where (ha-hr) / ha≤2%, then during the cycling process of the cell 100, as the electrolyte is continuously consumed, the cell 100 is not prone to lithium deposition at the end 121 of the first active material layer 12, and the performance of the cell 100 is excellent.

[0093] This application also provides an example of an electrical device, which includes a load and the aforementioned battery cell 100. The battery cell 100 is connected to the load and is used to supply power to the load.

[0094] Electrical equipment can be energy storage products, mobile phones, tablets, drones, electric vehicles with one or more wheels, or electric cleaning tools, etc.

[0095] For example, in the aforementioned drone, the battery pack is mounted on the drone and is used to power the drone's loads, including the flight system, control system, and camera system.

[0096] It should be noted that while preferred embodiments of this application are provided in the specification and accompanying drawings, this application can be implemented in many different forms and is not limited to the embodiments described herein. These embodiments are not intended to impose additional limitations on the content of this application; their purpose is to provide a more thorough and comprehensive understanding of the disclosure of this application. Furthermore, the above-described technical features can be combined with each other to form various embodiments not listed above, all of which are considered to be within the scope of this application's specification. Moreover, those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of the appended claims.

Claims

1. A battery cell, comprising alternately stacked first and second electrodes, with a separator between the first and second electrodes; the first electrode comprising a first current collector and a first active material layer disposed on the surface of the first current collector, the first current collector having a first tab, the direction in which the first tab extends out of the first current collector defined as the length direction of the battery cell; the second electrode comprising a second active material layer, characterized in that, The first active material layer includes a main body and an end portion. The end portion is provided with a transition section that is recessed relative to the main body and a protruding structure that is protruding relative to the transition section. The transition section is adjacent to the main body and the protruding structure. The second electrode includes a second current collector and a second active material layer disposed on the surface of the second current collector; Along the thickness direction of the battery cell, the thickness of the end of the second active material layer is less than the thickness of the main body of the second active material layer, and the transition section and the end of the second active material layer are stacked. Along the length of the battery cell, the protrusion extends beyond the end of the second active material layer; the thickness of the protrusion is set to be greater than the thickness of the main body of the first active material layer and less than the distance between the first current collector and the second current collector.

2. The battery cell according to claim 1, characterized in that, Along the thickness direction of the battery cell, the distance from the lowest point of the transition section surface to the surface of the first current collector is hr, and the thickness of the main body of the first active material layer is ha, wherein (ha-hr) / ha≤2% and ha>hr.

3. The battery cell according to claim 2, characterized in that, The first current collector is provided with a first tab, and the direction in which the first tab extends out of the first current collector is defined as the length direction of the battery cell; along the length direction of the battery cell, the distance from the lowest point of the surface of the transition section to the edge of the first active material layer is xr. Where 2mm≤xr≤4mm; The surface of the transition section has a point B, the distance from point B to the edge of the first active material layer is xb, xb-xr=2mm; the distance from point B to the surface of the first current collector is hb; Where (hb-hr) / (xb-xr)≤2.

4. The battery cell according to claim 3, characterized in that, Along the length of the battery cell, the distance from the vertex of the surface of the protruding structure to the edge of the first active material layer is xt, where 0.8mm≤xt≤1.2mm.

5. The battery cell according to claim 1, characterized in that, Along the length of the battery cell, the first active material layer extends beyond the second active material layer by a length of ΔL, where 0.5mm ≤ ΔL ≤ 3mm.

6. The battery cell according to claim 2, characterized in that, Along the thickness direction of the battery cell, the vertical distance from any point on the edge of the protruding structure to the surface of the first current collector is hp; Where 0.9ha≤hp.

7. The battery cell according to claim 6, characterized in that, The vertical distance from the vertex of the protrusion structure to the surface of the second current collector is Δhp, and the thickness of the main body of the second active material layer is hc, wherein Δhp ≥ 0.5hc, and the surface of the second current collector is the surface of the second current collector close to the protrusion structure.

8. The battery cell according to claim 1, characterized in that, The first current collector is provided with a first tab, and the direction in which the first tab extends out of the first current collector is defined as the length direction of the battery cell; Along the length of the battery cell, the separator extends beyond the first active material layer by a dimension of not less than 1 mm.

9. The battery cell according to claim 1, characterized in that, The first current collector is provided with a first tab, and the first tab is not provided with the first active material layer beyond the surface of the first current collector.

10. The battery cell according to claim 1, characterized in that, The distance from the edge of the first active material layer to the edge of the first current collector is less than or equal to 1 mm.

11. An electrical appliance, characterized in that, It includes a load and a battery cell as described in any one of claims 1 to 10, the battery cell being used to supply power to the load.

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