Negative plate, battery and vehicle

Abstract

The negative plate comprises a current collector and an active material layer, the current collector is provided with a first surface and a second surface which are opposite to each other, the active material layer is arranged on the first surface and / or the second surface, and the active material layer is provided with a first end and a second end which are opposite to each other along the length direction of the current collector. The first end and / or the second end are / is provided with a plurality of concave structures, the plurality of concave structures are arranged side by side at intervals, and the cross sectional areas of the concave structures are gradually reduced in the direction from the end part of the current collector to the middle position of the current collector. The line marking time of the concave structure close to the middle position of the current collector is shorter than the line marking time of the concave structure close to the end part of the current collector, so that the overall line marking time of the negative plate is shortened, and the production efficiency of the negative plate can be improved under the condition of reducing lithium precipitation.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, in particular to a negative electrode sheet, a battery and a vehicle. Background Art

[0002] To meet users' growing demand for shorter charging times for new energy vehicles, power batteries need to have high-current, high-rate charging capabilities. During rapid charging, a large current flows from the tabs to various areas of the electrode. Due to the cell structure and electrode design, it is impossible for the current to reach all areas of the electrode at the same time. The current density in the area near the tabs is greater than that in the area away from the tabs, and the uneven current density is more pronounced when the current is high. During rapid charging and long-term cycling, lithium deposition is more likely to occur in the area near the tabs.

[0003] To address the lithium deposition problem caused by uneven fast-charging current density, laser scribing is typically performed on the surface of the negative electrode sheet to increase the electrolyte infiltration rate and lithium ion diffusion capacity, thereby improving lithium deposition. However, the dimensions of the grooves scribed in the areas near the tabs and those away from the tabs are the same. However, the lithium deposition problem is more severe in the areas near the tabs than in the areas away from the tabs. Excessive scribing in the areas away from the tabs increases the scribing time required for the negative electrode sheet, resulting in low negative electrode sheet production efficiency. Utility Model Content

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a battery that can improve the production efficiency of negative electrode sheets while reducing lithium plating.

[0005] The utility model also provides a battery using the negative electrode sheet.

[0006] The utility model also provides a vehicle using the battery.

[0007] According to the negative electrode sheet in the embodiment of the first aspect of the present invention, it includes:

[0008] a current collector, wherein along a thickness direction of the current collector, the current collector has a first surface and a second surface opposite to each other, the first surface and the second surface being surfaces of the current collector with the largest surface areas;

[0009] An active material layer is provided on the first surface and / or the second surface. Along the length direction of the current collector, the active material layer has a first end and a second end relative to each other. The first end and / or the second end are provided with a plurality of recessed structures. The plurality of recessed structures are arranged side by side at intervals. In the length direction of the current collector, the cross-sectional area of ​​the recessed structure decreases from the end of the current collector to the middle position of the current collector.

[0010] The negative electrode sheet according to the embodiment of the first aspect of the present invention has at least the following beneficial effects:

[0011] When the negative electrode sheet of this embodiment is laser engraved, a recessed structure is generated on the surface of the active material layer. Since the cross-sectional area of ​​the recessed structure near the end of the current collector is larger than the cross-sectional area near the middle of the current collector, when the laser power of the laser system remains unchanged, the engraving time of the recessed structure near the middle of the current collector is shorter than the engraving time of the recessed structure near the end of the current collector, thereby reducing the overall engraving time of the negative electrode sheet and improving the production efficiency of the negative electrode sheet while reducing lithium plating.

[0012] In other embodiments of the present invention, in the length direction of the current collector, along the direction from the end of the current collector to the middle position of the current collector, the minimum distance between two adjacent recessed structures increases gradually.

[0013] In other embodiments of the present invention, the minimum distance between two adjacent recessed structures is greater than or equal to 0.3 mm and less than or equal to 10 mm.

[0014] In other embodiments of the present invention, in the length direction of the current collector, the depth of the recessed structure decreases gradually along the direction from the end of the current collector to the middle position of the current collector.

[0015] In other embodiments of the present invention, in the length direction of the current collector, the width of the recessed structure decreases gradually along the direction from the end of the current collector to the middle position of the current collector.

[0016] In other embodiments of the present invention, in the length direction of the current collector, the depth of the recessed structure gradually decreases along the direction from the end of the current collector to the middle position of the current collector.

[0017] In other embodiments of the present invention, a plurality of the recessed structures are arranged side by side and spaced apart along the width direction of the current collector, or a plurality of the recessed structures are arranged side by side and spaced apart along the length direction of the current collector.

[0018] In other embodiments of the present invention, the recessed structure includes a plurality of grooves, and the plurality of grooves are arranged side by side and spaced apart along a direction perpendicular to an arrangement direction of the plurality of recessed structures.

[0019] According to the battery of the embodiment of the second aspect of the present invention, the battery includes a shell and a battery cell, the battery cell is arranged in the shell, the battery cell includes a diaphragm, a plurality of positive electrode sheets and a plurality of negative electrode sheets according to the embodiment of the first aspect of the present invention, the negative electrode sheets and the positive electrode sheets are alternately stacked, the diaphragm is arranged between the positive electrode sheets and the negative electrode sheets, the negative electrode sheets are provided with a negative electrode ear, the positive electrode sheets are provided with a positive electrode ear, the negative electrode ear is provided on one side of the length direction of the battery cell, and the positive electrode ear is provided on the other side of the length direction of the battery cell.

[0020] The battery according to the embodiment of the second aspect of the present utility model has at least the following beneficial effects:

[0021] When the negative electrode sheet of the first embodiment of the utility model is laser-engraved, a recessed structure is generated on the surface of the active material layer. Since the cross-sectional area of ​​the recessed structure near the end of the current collector is larger than the cross-sectional area near the middle position of the current collector, when the laser power of the laser system remains unchanged, the engraving time of the recessed structure near the middle position of the current collector is shorter than the engraving time of the recessed structure near the end of the current collector, thereby reducing the overall engraving time of the negative electrode sheet and improving the production efficiency of the negative electrode sheet while reducing lithium plating.

[0022] A vehicle according to an embodiment of the third aspect of the present invention includes the battery described in the embodiment of the second aspect of the present invention.

[0023] Additional aspects and advantages of the present invention will be given in part in the following description and will become apparent from the following description or learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The present invention will be further described below with reference to the accompanying drawings and embodiments, wherein:

[0025] Figure 1 A top view of a first embodiment of a negative electrode sheet according to an embodiment of the present invention;

[0026] Figure 2 for Figure 1 Cross-sectional view along line AA;

[0027] Figure 3 A top view of a second embodiment of the negative electrode sheet of the present invention;

[0028] Figure 4 A top view of a third embodiment of the negative electrode sheet of the present invention;

[0029] Figure 5 for Figure 4 Cross-sectional view along the midline BB;

[0030] Figure 6 This is a top view of a fourth embodiment of the negative electrode sheet of the present invention.

[0031] Reference numerals:

[0032] Current collector 100 , first surface 101 , second surface 102 , negative electrode tab 103 , active material layer 200 , first end 201 , second end 202 , recessed structure 210 , groove 211 . DETAILED DESCRIPTION

[0033] The following describes embodiments of the present invention in detail. Examples of the embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals throughout represent the same or similar elements or elements having the same or similar functions. The embodiments described below with reference to the accompanying drawings are exemplary and are intended only to explain the present invention and are not to be construed as limiting the present invention.

[0034] In the description of the present invention, it should be understood that descriptions involving orientations, such as up, down, front, back, left, right, etc., indicating orientations or positional relationships, are based on the orientations or positional relationships shown in the accompanying drawings. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, they cannot be understood as limitations on the present invention.

[0035] In the description of this utility model, "several" means more than one, "plurality" means more than two, "greater than," "less than," and "exceed" are understood to exclude the number itself, while "above," "below," and "within" are understood to include the number itself. The use of the terms "first" and "second" is solely for the purpose of distinguishing technical features and is not to be construed as indicating or implying relative importance, implicitly specifying the number of the indicated technical features, or implicitly specifying the order of the indicated technical features.

[0036] In the description of the present invention, unless otherwise clearly defined, terms such as setting, installing, connecting, etc. should be understood in a broad sense, and technicians in the relevant technical field can reasonably determine the specific meanings of the above terms in the present invention based on the specific content of the technical solution.

[0037] In the description of the present invention, reference to terms such as "one embodiment," "some embodiments," "illustrative embodiments," "examples," "specific examples," or "some examples" means that the specific features, structures, materials, or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the exemplary expressions of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

[0038] As mentioned above, to address the lithium deposition problem caused by uneven fast-charging current density, laser scribing is generally performed on the surface of the negative electrode sheet to increase the electrolyte infiltration rate and lithium ion diffusion capacity, thereby improving lithium deposition. The existing negative electrode sheets have the same size of grooves carved in the areas near the tabs and those away from the tabs. However, the lithium deposition problem in the areas near the tabs is more serious than that in the areas away from the tabs. Excessive scribing in the areas away from the tabs increases the scribing time required for the negative electrode sheet, resulting in low production efficiency of the negative electrode sheet. Based on this, the present invention proposes a negative electrode sheet, in which the cross-sectional area of ​​the recessed structure 210 decreases along the length direction of the current collector 100 from the end of the current collector 100 to the middle position of the current collector 100, so that the cross-sectional area of ​​the recessed structure 210 near the end of the current collector 100 is larger than the cross-sectional area near the middle position of the current collector 100. When the laser power of the laser system remains unchanged, the engraving time of the recessed structure 210 near the middle position of the current collector 100 is shorter than the engraving time of the recessed structure 210 near the end of the current collector 100, so that the overall engraving time of the negative electrode sheet is reduced, which can improve the production efficiency of the negative electrode sheet while reducing lithium plating. In addition, it can also reduce the loss of active material in the area of ​​the active material layer 200 near the middle position of the current collector 100, thereby improving the energy density of the battery.

[0039] It should be noted that the current density near the middle position of the current collector 100 is lower than the current density near the end of the current collector 100, so that the lithium deposition problem in the area of ​​the active material layer 200 near the end of the current collector 100 is more serious than the lithium deposition problem in the area of ​​the active material layer 200 near the middle position of the current collector 100. Compared with the area of ​​the active material layer 200 near the middle position of the current collector 100, the area of ​​the active material layer 200 near the end of the current collector 100 requires more electrolyte to reduce the amount of lithium deposition in the area of ​​the active material layer 200 near the end of the current collector 100.

[0040] It should be noted that the cross-sectional area of ​​the groove structure refers to the cross-sectional area of ​​the groove structure in the length direction of the current collector 100 .

[0041] It can be understood that, from the perspective of the electrolyte infiltration speed, the recessed structure 210 near the end of the current collector 100 can accommodate more electrolyte compared to the recessed structure 210 near the middle of the current collector 100, that is, the electrolyte infiltration area of ​​the active material layer 200 near the end of the current collector 100 is larger than the electrolyte infiltration area of ​​the active material layer 200 near the middle of the current collector 100, and the electrolyte infiltration speed is proportional to the electrolyte infiltration area, that is, the larger the infiltration area of ​​a certain area, the faster the electrolyte infiltration speed of the area. By engraving a recessed structure 210 with a larger cross-sectional area in the area near the end of the current collector 100 of the active material layer 200, the electrolyte infiltration speed of the area near the end of the current collector 100 of the active material layer 200 can be increased to reduce the amount of lithium precipitation in the active material layer 200. By engraving a recessed structure 210 with a smaller cross-sectional area in the middle area of ​​the active material layer 200 near the current collector 100, the loss of active material can be reduced, which can not only improve the energy density of the battery, but also speed up the engraving speed of the negative electrode sheet, thereby improving the production efficiency of the negative electrode sheet.

[0042] Reference Figure 1 、 Figure 2 , Figure 1 A top view of a first embodiment of the negative electrode sheet of the present utility model is shown. Figure 2 for Figure 1 Cross-sectional view of the middle AA line. In the blade battery, the battery cell is a laminated structure, and the positive and negative tabs 103 of the battery cell are respectively arranged on both sides of the length direction of the battery cell. The end of the negative electrode sheet away from the negative tab 103 is close to the positive tab, so that the current density at both ends of the negative electrode sheet in the length direction is greater than the current density in the middle position of the negative electrode sheet. The lithium deposition problem at both ends of the negative electrode sheet in the length direction is more serious. In order to reduce the amount of lithium deposition at both ends of the negative electrode sheet in the length direction, as shown in FIG. Figure 1 As shown, a negative electrode ear 103 is provided on one side of the current collector 100 near the first end 201. When the negative electrode sheets and the positive electrode sheets are alternately stacked, the side of the current collector 100 near the second end 202 is close to the positive electrode ear of the positive electrode sheet, so that the area of ​​the current collector 100 near the first end 201 and the area of ​​the current collector 100 near the second end 202 are both areas with higher current density. A plurality of recessed structures 210 are provided in the area of ​​the active material layer 200 near the first end 201, and a plurality of recessed structures 210 are also provided in the area of ​​the active material layer 200 near the second end 202. The cross-sectional area of ​​the recessed structure 210 decreases from the two ends of the length direction of the current collector 100 to the middle position of the current collector 100, that is, the cross-sectional area of ​​the recessed structure 210 located in the middle position of the active material layer 200 is smaller than the cross-sectional area of ​​the recessed structure 210 located at the two ends of the length direction of the current collector 100, which can simultaneously reduce the amount of lithium plating at both ends of the length direction of the negative electrode sheet, thereby improving the service life of the battery.

[0043] It should be noted that along the width direction of the current collector 100, the multiple recessed structures 210 located at the first end 201 and the multiple recessed structures 210 located at the second end 202 are arranged in a mirror-symmetrical manner around the central axis of the current collector 100. After the operator laser-scribes the first end 201 of the active material layer 200, he can rotate it 180 degrees to laser-scribe the second end 202 of the active material layer 200. The operation is simple, convenient and fast, and can facilitate the engraving of the active material layer 200.

[0044] As another embodiment, one of the first end 201 and the second end 202 may be provided with a plurality of recessed structures 210, while the other end may not be provided with a recessed structure 210. For example, when the first end 201 is provided with a plurality of recessed structures 210 and the second end 202 is not provided with a recessed structure 210, the amount of lithium precipitated from the active material layer 200 near the first end 201 is less than the amount of lithium precipitated from the active material layer 200 near the second end 202. Overall, the total amount of lithium precipitated from the negative electrode sheet is also reduced accordingly. Similarly, when the second end 202 is provided with a plurality of recessed structures 210 and the first end 201 is not provided with a recessed structure 210, the amount of lithium precipitated from the active material layer 200 near the first end 201 is greater than the amount of lithium precipitated from the active material layer 200 near the second end 202, which will not be described in detail here.

[0045] For example Figure 2 As shown, the first surface 101 and the second surface 102 of the current collector 100 are arranged relative to each other along the thickness direction of the current collector 100, and the first surface 101 and the second surface 102 of the current collector 100 are both provided with an active material layer 200. The active material layer 200 can be coated on the first surface 101 and the second surface 102 of the current collector 100 by a double-sided coating process. The first end 201 of the active material layer 200 located on the first surface 101, the second end 202 of the active material layer 200 located on the first surface 101, the first end 201 of the active material layer 200 located on the second surface 102, and the second end 202 of the active material layer 200 located on the second surface 102 are respectively provided with a plurality of recessed structures 210. On the one hand, the active material content of the negative electrode sheet can be increased, thereby improving the energy density of the battery. On the other hand, the amount of lithium plating of the negative electrode sheet can be reduced to ensure that the battery can work normally.

[0046] As another embodiment, the active material layer 200 can be provided on one of the first surface 101 and the second surface 102 of the current collector 100. The active material layer 200 can be coated on the surface of the current collector 100 using a single-sided coating process. Compared with the negative electrode sheet coated on one side, the negative electrode sheet coated on both sides has a higher active material content. Under the same volume and weight, the battery energy density of the negative electrode sheet coated on both sides is higher. The negative electrode sheet coated on one side has a larger surface area and better heat dissipation, thereby improving the safety of the battery.

[0047] In order to increase the etching speed of the negative electrode sheet, for example Figure 1 As shown, in the length direction of the current collector 100, the spacing between adjacent grooves 211 increases along the direction from the end of the current collector 100 to the middle position of the current collector 100, so that the number of recessed structures 210 is reduced. On the one hand, it can reduce the loss of active materials to improve the energy density of the battery. On the other hand, it can reduce the number of recessed structures 210, thereby increasing the speed of engraving the negative electrode sheet and improving the production efficiency of the negative electrode sheet. Specifically, the density of the recessed structures 210 near the end of the current collector 100 is greater than the density near the middle position of the current collector 100, and the cross-sectional area of ​​the recessed structures 210 near the end of the current collector 100 is greater than the cross-sectional area near the middle position of the current collector 100, so that the electrolyte infiltration speed of the first end 201 and the second end 202 of the active material layer 200 is faster than the electrolyte infiltration speed of the middle position of the active material layer 200, which can reduce the amount of lithium deposition on the negative electrode sheet.

[0048] For example Figure 1 As shown, a plurality of recessed structures 210 are arranged side by side and spaced apart along the length direction of the current collector 100. In the length direction of the current collector 100, along the direction from the end of the current collector 100 to the middle position of the current collector 100, the plurality of recessed structures 210 include a first recessed structure, a second recessed structure, a third recessed structure, ..., an n-2th recessed structure, an n-1th recessed structure and an nth recessed structure, which are sequentially spaced apart. The minimum distance between the first recessed structure and the second recessed structure is L1, the minimum distance between the second recessed structure and the third recessed structure is L2, and the minimum distance between the n-2th recessed structure and the n-1th recessed structure is L n-2 , the minimum distance between the n-1th concave structure and the nth concave structure is L n-1 , satisfying: L1<L2<.....<L n-2 <L n-1 , and 0.3mm≤L n-1 ≤10mm, which can not only reduce the amount of lithium plating on the negative electrode sheet, but also reduce the loss of active materials, thereby improving the battery energy density.

[0049] When n>1, 0.3mm≤L1≤2mm, and 1mm≤L n-1 When L1 is ≤10mm, it can improve the efficiency of laser scribing while reducing the loss of active materials, thereby increasing the energy density of the battery. For example, when L1 is 0.3mm and L n-1 When L2 to L is 10mm n-2 The value of is in the range of 0.3mm to 10mm. When L1 is 2mm, L n-1 When L2 to L is 10mm n-2 The value is in the range of 2mm to 10mm.

[0050] If L n-1 If the minimum distance between adjacent recessed structures 210 is less than 0.3 mm, the minimum distance between adjacent recessed structures 210 is too small. On the one hand, there is a certain error in the laser scribing, and adjacent recessed structures 210 are likely to overlap with each other, affecting the scribing effect of the active material layer. On the other hand, the number of recessed structures 210 increases, resulting in excessive loss of active material and reduced laser scribing efficiency.

[0051] If L n-1 If the minimum distance between adjacent recessed structures 210 is greater than 10 mm, the minimum distance between adjacent recessed structures 210 is too large. Due to the limited length of the current collector 100, the number of recessed structures 210 is too small, which cannot effectively increase the electrolyte infiltration speed, and the diffusion capacity of lithium ions is also reduced. The lithium deposition phenomenon of the negative electrode sheet is not effectively alleviated.

[0052] If L n-1 When the minimum distance between adjacent recessed structures 210 is greater than 0.3 mm and less than 10 mm, it is moderate, which can improve the efficiency of laser scribing and reduce the loss of active material, thereby increasing the energy density of the battery. In addition, it can also limit the amount of lithium deposition on the negative electrode sheet, thereby increasing the service life of the battery.

[0053] For example Figure 2 As shown, in this embodiment, in the length direction of the current collector 100, the depth difference of adjacent recessed structures 210 along the direction from the end of the current collector 100 to the middle position of the current collector 100 is equal, that is, the depths of the multiple recessed structures 210 are in an arbitrarily decreasing relationship, so that the depth of the recessed structure 210 near the middle position of the active material layer 200 of the current collector 100 is shallower. On the one hand, it can reduce the loss of active materials, thereby improving the energy density of the battery. On the other hand, it can reduce the time required for laser engraving, thereby improving the laser engraving speed.

[0054] As another embodiment, in the length direction of the current collector 100, the depth difference between adjacent recessed structures 210 along the direction from the end of the current collector 100 to the middle position of the current collector 100 can also gradually increase, which can reduce the number of groove structures, reduce the loss of active materials, and improve the laser scribing efficiency.

[0055] Based on the first embodiment of the negative electrode sheet, in the length direction of the current collector 100, the depth of the recessed structure 210 decreases from the end of the current collector 100 to the middle position of the current collector 100. On the one hand, it can reduce the loss of active materials, thereby improving the energy density of the battery. On the other hand, it can reduce the time required for laser scribing, thereby improving the laser scribing speed.

[0056] It should be noted that the depth of the first concave structure is h1, the depth of the second concave structure is h2, ..., the depth of the n-1th concave structure is h n-1 , the depth of the nth concave structure is h n , the thickness of the active material layer is H, satisfying: h1>h2>....>h n-1 >h n , and 0<h n / H≤0.75, which can not only avoid damage to the current collector, but also ensure the infiltration speed of the electrolyte to reduce the amount of lithium plating on the negative electrode sheet, thereby increasing the service life of the battery.

[0057] When n>1, 0.1≤h1 / H≤0.75, and 0<h n When / H≤0.4, h1 is the maximum critical value. In order to ensure the depth of the first concave structure, it satisfies: 0.1≤h1 / H≤0.75, and 0<h n / H≤0.4, it can improve the efficiency of laser scribing while reducing the loss of active materials, thereby increasing the energy density of the battery. For example, when h1 / H is 0.75, h n When / H is 0.4, h2 / H to h n-1 The value of h1 / H is in the range of 0.4 to 0.75. When h1 / H is 0.1, h n When / H is greater than 0, h2 / H to h n-1 The value of / H is in the range of 0 to 0.1.

[0058] If h1 / H is greater than 0.75, the depth of the first recessed structure is too deep, and the distance between the bottom of the first recessed structure and the current collector is too small. On the one hand, when the laser power of the laser system fluctuates greatly, the laser can easily penetrate the active material layer, thereby damaging the first surface or the second surface. On the other hand, the active material is lost too much, resulting in a decrease in the energy density of the battery.

[0059] Based on the first embodiment of the negative electrode sheet, in the length direction of the current collector 100, the width of the recessed structure 210 decreases from the end of the current collector 100 to the middle position of the current collector 100, so that the width of the recessed structure 210 near the middle position of the active material layer 200 of the current collector 100 is narrower. On the one hand, it can reduce the loss of active material, thereby improving the energy density of the battery. On the other hand, it can reduce the time required for laser engraving, thereby improving the laser engraving speed.

[0060] Specifically, the width of the first concave structure is M1, the width of the second concave structure is M2, ..., the width of the n-1th concave structure is M n-1 , the width of the nth concave structure is M n , satisfying: M1>M2>....>M n-1 >M n , and 0<M n ≤200μm;

[0061] When n>1, 50μm≤M1≤200μm, and 0≤M n When M1 is ≤120μm, it can improve the efficiency of laser scribing while reducing the loss of active materials, thereby increasing the energy density of the battery. For example, when M1 is 200μm and M n When the M2 to M n-1 The value of is in the range of 120μm to 200μm. When M1 is 50μm, M n When the M2 to M n-1 The value is in the range of 10μm to 50μm.

[0062] If M1 is greater than 200 μm, the width of the first recessed structure is too wide, which not only increases the laser scribing time but also causes excessive loss of active materials, thereby reducing the energy density of the battery.

[0063] Reference Figure 3 , Figure 3 FIG2 shows a top view of a second embodiment of the negative electrode sheet of the present utility model. Figure 3 As shown, the recessed structure 210 includes a plurality of grooves 211. Along the width direction of the current collector 100, the plurality of grooves 211 are arranged side by side and spaced apart. Compared with the first embodiment of the negative electrode sheet, the second embodiment of the negative electrode sheet can increase the infiltration speed of the electrolyte while reducing the loss of active materials, thereby improving the energy density of the battery.

[0064] Reference Figure 4 , Figure 5 , Figure 4 A top view of a third embodiment of the negative electrode sheet of the present utility model is shown. Figure 5 for Figure 4Cross-sectional view of the middle BB line. Figure 4 As shown, the first end 201 and the second end 202 are both provided with a plurality of groove structures. Along the width direction of the current collector 100, a plurality of recessed structures 210 are arranged side by side at intervals. The recessed structures 210 are long groove structures. In the length direction of the current collector 100, along the direction from the end of the current collector 100 to the middle position of the current collector 100, the width of the recessed structure 210 gradually decreases. Along the width direction of the current collector 100, the minimum distance between adjacent recessed structures 210 gradually increases, which can increase the infiltration speed of the electrolyte while reducing the loss of active materials, thereby improving the energy density of the battery.

[0065] For example Figure 5 As shown, in the length direction of the current collector 100 , the depth of the recessed structure 210 gradually decreases from the end of the current collector 100 to the middle position of the current collector 100 , which can reduce the loss of active materials.

[0066] Reference Figure 6 , Figure 6 FIG. 4 shows a top view of a fourth embodiment of a negative electrode sheet according to an embodiment of the present invention. Figure 6 As shown, the recessed structure 210 includes a plurality of grooves 211, which are arranged side by side and spaced apart along the length direction of the current collector 100. Compared with the third embodiment of the negative electrode sheet, the fourth embodiment of the negative electrode sheet can increase the infiltration speed of the electrolyte while reducing the loss of active materials, thereby improving the energy density of the battery.

[0067] The second embodiment of the present invention provides a battery, including a shell and a battery cell, which is arranged in the shell. The battery cell includes a diaphragm, multiple positive electrode sheets and multiple negative electrode sheets according to the first embodiment of the present invention. The negative electrode sheets and the positive electrode sheets are alternately stacked, and the diaphragm is arranged between the positive electrode sheets and the negative electrode sheets. The negative electrode sheets are provided with negative electrode ears 103, and the positive electrode sheets are provided with positive electrode ears. The negative electrode ears 103 are provided on one side of the length direction of the battery cell, and the positive electrode ears are provided on the other side of the length direction of the battery cell.

[0068] When the negative electrode sheet of the embodiment of the first aspect of the present invention is laser-engraved, a recessed structure 210 is generated on the surface of the active material layer 200. Since the cross-sectional area of ​​the recessed structure 210 near the end of the current collector 100 is larger than the cross-sectional area near the middle position of the current collector 100, when the laser power of the laser system remains unchanged, the engraving time of the recessed structure 210 near the middle position of the current collector 100 is shorter than the engraving time of the recessed structure 210 near the end of the current collector 100, thereby reducing the overall engraving time of the negative electrode sheet, and improving the production efficiency of the negative electrode sheet while reducing lithium plating.

[0069] The third embodiment of the present invention provides a vehicle comprising the battery according to the second embodiment of the present invention. The vehicle may be a private vehicle, such as a sedan, SUV, MPV, or pickup truck. It may also be a commercial vehicle, such as a van, bus, small truck, or large trailer. It may be a gasoline vehicle or a new energy vehicle. When the vehicle is a new energy vehicle, it may be a hybrid vehicle or a pure electric vehicle.

[0070] The embodiments of the present invention have been described in detail above with reference to the accompanying drawings. However, the present invention is not limited to the above embodiments. Various modifications can be made within the scope of knowledge possessed by a person skilled in the art without departing from the spirit of the present invention. In addition, the embodiments of the present invention and the features of the embodiments can be combined with each other unless there is a conflict.

Claims

1. A negative electrode sheet, characterized in that: include: a current collector, wherein along a thickness direction of the current collector, the current collector has a first surface and a second surface opposite to each other; An active material layer is provided on the first surface and / or the second surface. Along the length direction of the current collector, the active material layer has a first end and a second end relative to each other. The first end and / or the second end are provided with a plurality of recessed structures. The plurality of recessed structures are arranged side by side at intervals. In the length direction of the current collector, the cross-sectional area of ​​the recessed structure decreases from the end of the current collector to the middle position of the current collector.

2. The negative electrode sheet according to claim 1, characterized in that: In the length direction of the current collector, along the direction from the end of the current collector to the middle position of the current collector, the minimum distance between two adjacent recessed structures increases gradually.

3. The negative electrode sheet according to claim 2, characterized in that: The minimum distance between two adjacent recessed structures is greater than or equal to 0.3 mm and less than or equal to 10 mm.

4. The negative electrode sheet according to claim 1, characterized in that: In the length direction of the current collector, the depth of the recessed structure decreases gradually along the direction from the end of the current collector to the middle position of the current collector.

5. The negative electrode sheet according to claim 1, characterized in that: In the length direction of the current collector, the width of the recessed structure decreases gradually along the direction from the end of the current collector to the middle position of the current collector.

6. The negative electrode sheet according to claim 1, characterized in that: In the length direction of the current collector, the depth of the recessed structure gradually decreases along a direction from an end portion of the current collector to a middle position of the current collector.

7. The negative electrode sheet according to claim 1, characterized in that: The plurality of recessed structures are arranged side by side and spaced apart along the width direction of the current collector, or the plurality of recessed structures are arranged side by side and spaced apart along the length direction of the current collector.

8. The negative electrode sheet according to claim 1, characterized in that: The recessed structure includes a plurality of grooves, and the plurality of grooves are arranged side by side and spaced apart along a direction perpendicular to an arrangement direction of the plurality of recessed structures.

9. A battery, characterized in that include: A shell and a battery cell, the battery cell is arranged in the shell, the battery cell includes a diaphragm, multiple positive electrode sheets and multiple negative electrode sheets according to any one of claims 1 to 8, the negative electrode sheets and the positive electrode sheets are alternately stacked, the diaphragm is arranged between the positive electrode sheets and the negative electrode sheets, the negative electrode sheet is provided with a negative electrode ear, the positive electrode sheet is provided with a positive electrode ear, the negative electrode ear is provided on one side of the length direction of the battery cell, and the positive electrode ear is provided on the other side of the length direction of the battery cell.

10. A vehicle, characterized in that include: The battery according to claim 9.

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