Battery negative plate and lithium ion battery

Abstract

The utility model provides a battery negative plate and a lithium ion battery. The battery negative electrode plate comprises a negative electrode current collector and a negative electrode active material layer, the negative electrode active material layer is arranged on the negative electrode current collector, at least n continuous wire slots are respectively formed in edge areas of two sides of the negative electrode active material layer in the width direction, n is a positive integer, and each continuous wire slot is arranged along the length direction of the negative electrode active material layer. According to the battery negative plate, on the premise of improving lithium precipitation at the edge of the battery negative plate, the loss amount of the active substance can be effectively reduced, so that a user does not need to additionally increase the use amount of the coated active substance, the rolling thickness of the battery negative plate is not increased, and the service life of the battery negative plate is prolonged. And the volume utilization rate and the cell energy density of the battery negative plate are not reduced.

Description

Technical Field

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

[0002] At present, during the charging process of lithium-ion batteries, due to the uneven temperature distribution and the order of lithium insertion in the electrode, lithium is easily deposited at the edge of the negative electrode, resulting in poor fast charging performance of lithium-ion batteries. In order to solve the above technical problems, the coated negative electrode is usually scribed on the entire surface or punched on the entire surface / both sides to improve the dynamics of the edge of the negative electrode, thereby effectively improving the lithium deposition phenomenon at the edge of the negative electrode.

[0003] However, in practical applications, the two traditional methods have the following shortcomings:

[0004] 1. For the method of full-surface scribing, since the negative electrode active material layer needs to be fully scribed, it causes great damage to the active material and causes a large loss of active material. In order to solve the problem of large loss of active material, it is necessary to increase the amount of coated active material to make up for the loss of active material due to scribing. However, this will increase the thickness of the rolled negative electrode sheet, which not only reduces the energy density of the battery cell, but also reduces the volume utilization of the negative electrode sheet and increases the production cost.

[0005] 2. For the method of drilling holes on the whole surface / both sides, for example, patent number CN219626686U discloses a negative electrode sheet. Although it can effectively solve the problem of easy lithium deposition on both sides of the negative electrode sheet in the width direction, the gap between each two adjacent holes still has the phenomenon of lithium deposition, that is, the dynamics of the edge of the negative electrode sheet is relatively poor. In addition, the drilling method is difficult to process and the uniformity of the drilling is poor.

[0006] Therefore, it is urgent to develop a new type of battery negative electrode. Utility Model Content

[0007] The purpose of the utility model is to overcome the shortcomings of the prior art and to provide a battery negative electrode sheet and a lithium ion battery negative electrode sheet that can effectively reduce the loss of active substances under the premise of improving the lithium deposition at the edge of the battery negative electrode sheet. Since the lines are only drawn at the edge of the battery negative electrode sheet, the width of the battery negative electrode sheet is greater than the width of the battery positive electrode sheet, so that the portion of the battery negative electrode sheet that exceeds the width of the battery positive electrode sheet can receive a portion of the lithium ions transferred from the positive electrode, thereby ensuring that the user does not need to increase the amount of active substances coated, thereby not reducing the volume utilization rate of the battery negative electrode sheet and the energy density of the battery cell.

[0008] The purpose of this utility model is achieved through the following technical solutions:

[0009] A battery negative electrode sheet comprises a negative electrode current collector and a negative electrode active material layer, wherein the negative electrode active material layer is arranged on the negative electrode current collector, and at least n continuous linear grooves are respectively formed on both side edge regions in the width direction of the negative electrode active material layer, and n is a positive integer, and each of the continuous linear grooves is arranged along the length direction of the negative electrode active material layer.

[0010] In one embodiment, the distances between the two ends of the continuous linear groove and the two ends of the negative electrode active material layer are both 0 mm to 20 mm.

[0011] In one embodiment, the continuous linear grooves are evenly distributed along the width direction of the negative electrode active material layer.

[0012] In one embodiment, the continuous linear groove is a continuous laser linear groove.

[0013] In one embodiment, the width of the edge area is 0.5 mm to 5 mm.

[0014] In one embodiment, the spacing between the continuous wire grooves is 0.5 mm to 3 mm.

[0015] In one embodiment, the number n is 1≤n≤5.

[0016] In one embodiment, the continuous wire groove is in the shape of a continuous curve or a continuous straight line.

[0017] In one embodiment, when the continuous groove is in the form of a continuous straight line, the depth of the continuous groove is 5 μm to 30 μm, and the width of the continuous groove is 10 μm to 200 μm; and / or,

[0018] When the continuous linear groove is in the shape of a continuous curve, the depth of the continuous linear groove is 5 μm to 30 μm, and the diameter of the continuous linear groove is 20 μm to 500 μm.

[0019] A lithium-ion battery comprises the battery negative electrode sheet described in any one of the above embodiments.

[0020] Compared with the prior art, the utility model has at least the following advantages:

[0021] Since at least n continuous linear grooves are formed on both side edge regions in the width direction of the negative electrode active material layer, and each of the continuous linear grooves is arranged along the length direction of the negative electrode active material layer, it is ensured that the continuous linear grooves are evenly distributed in the length direction of the negative electrode active material layer, thereby ensuring that the dynamics of the edge of the battery negative electrode sheet is better, effectively reducing the problem of lithium deposition at the edge of the battery negative electrode sheet, and greatly improving the lithium deposition phenomenon at the edge of the battery negative electrode sheet 10, and ensuring that the middle part of the negative electrode active material layer in the width direction is not provided with a continuous linear groove, thereby ensuring that the active material in the middle part of the negative electrode active material layer will not be destroyed , effectively reducing the loss of active materials. In this way, since lines are only drawn on the edges of the two sides of the negative electrode sheet of the battery, and the width of the negative electrode sheet of the battery is greater than that of the positive electrode sheet of the battery, the portion of the negative electrode sheet of the battery that exceeds the width of the positive electrode sheet of the battery can receive a portion of the lithium ions transferred from the positive electrode sheet of the battery. Under the premise of improving the lithium deposition at the edge of the negative electrode sheet of the battery, the loss of active materials can be effectively reduced, thereby ensuring that the user does not need to increase the amount of active materials coated, thereby ensuring that the thickness of the rolled negative electrode sheet of the battery will not increase, thereby not reducing the volume utilization rate of the negative electrode sheet of the battery and the energy density of the battery cell. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions of the embodiments of the utility model, the drawings required for use in the embodiments will be briefly introduced below. It should be understood that the following drawings only show certain embodiments of the utility model and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 A schematic diagram of the structure of a negative electrode sheet of a battery in one direction according to an embodiment of the utility model;

[0024] Figure 2 for Figure 1 A partial enlarged view shown in the middle A;

[0025] Figure 3 A schematic diagram of the structure of a negative electrode sheet of a battery in one direction according to another embodiment of the utility model;

[0026] Figure 4 for Figure 3 A partial enlarged view shown at B in the figure.

[0027] Reference numerals: 10, battery negative electrode sheet; 100, current collector; 200, negative electrode active material layer; 210, continuous linear groove. DETAILED DESCRIPTION

[0028] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively with reference to the relevant drawings. The drawings provide preferred embodiments of the present invention. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. On the contrary, the purpose of providing these embodiments is to make the disclosure of the present invention more thoroughly and comprehensively understood.

[0029] It should be noted that when an element is referred to as being "fixed to" another element, it may be directly on the other element or there may be a central element. When an element is considered to be "connected to" another element, it may be directly connected to the other element or there may be a central element at the same time. The terms "vertical", "horizontal", "left", "right" and similar expressions used herein are for illustrative purposes only and do not represent the only implementation method.

[0030] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art in the technical field of the present invention. The terms used herein in the specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention. The term "and / or" used herein includes any and all combinations of one or more related listed items.

[0031] In order to better understand the technical solutions and beneficial effects of the present invention, the present invention is further described in detail below in conjunction with specific embodiments:

[0032] like Figure 1 and Figure 2 As shown, a battery negative electrode sheet 10 of an embodiment includes a negative electrode current collector 100 and a negative electrode active material layer 200, wherein the negative electrode active material layer 200 is arranged on the negative electrode current collector 100, and at least n continuous linear grooves 210 are respectively formed at the edge regions on both sides in the width direction of the negative electrode active material layer 200, and n is a positive integer, and each of the continuous linear grooves 210 is arranged along the length direction of the negative electrode active material layer 200.

[0033] It can be understood that, since at least n continuous linear grooves 210 are formed on the edge areas on both sides in the width direction of the negative electrode active material layer 200, and each of the continuous linear grooves 210 is arranged along the length direction of the negative electrode active material layer 200, it is ensured that the continuous linear grooves 210 are evenly distributed in the length direction of the negative electrode active material layer 200, thereby ensuring that the dynamics of the edge of the battery negative electrode sheet 10 is good, effectively reducing the problem of lithium deposition at the edge of the battery negative electrode sheet 10, and well improving the lithium deposition phenomenon at the edge of the battery negative electrode sheet 10, and ensuring that the middle part of the negative electrode active material layer 200 in the width direction is not provided with a continuous linear groove 210, thereby ensuring the negative electrode active material layer 200 The active material in the middle will not be destroyed, and the loss of active material will be effectively reduced. In this way, since lines are only drawn on the edges of both sides of the battery negative electrode sheet 10, and the width of the battery negative electrode sheet 10 is greater than the width of the battery positive electrode sheet, the portion of the battery negative electrode sheet 10 that exceeds the width of the battery positive electrode sheet can receive a portion of the lithium ions transferred from the battery positive electrode sheet. Under the premise of improving the lithium deposition at the edge of the battery negative electrode sheet 10, the loss of active material can also be effectively reduced, thereby ensuring that the user does not need to increase the amount of coated active material, thereby ensuring that the thickness of the rolled battery negative electrode sheet 10 will not increase, and thereby will not reduce the volume utilization rate of the battery negative electrode sheet 10 and the energy density of the battery cell.

[0034] It can also be understood that, compared with the punching method, the scribing method adopted in the present disclosure not only reduces the processing difficulty, but also can better ensure the uniformity of the multiple continuous line grooves 210.

[0035] It should also be noted that, since only the edges of the two sides of the battery negative electrode sheet 10 are scribed, the lithium deposition phenomenon at the edge of the battery negative electrode sheet 10 can be effectively solved and improved, and the volume utilization rate of the battery negative electrode sheet 10 and the energy density of the battery cell will not be reduced. When the width of the battery negative electrode sheet 10 is greater than the width of the battery positive electrode sheet, the portion of the battery negative electrode sheet 10 that exceeds the width of the battery positive electrode sheet can receive a portion of the lithium ions transferred from the battery positive electrode sheet, thereby better improving the lithium deposition phenomenon at the edge of the battery negative electrode sheet 10 and better ensuring the energy density of the battery cell.

[0036] like Figure 2 As shown, in one embodiment, the distances between the two ends of the continuous linear groove 210 and the two ends of the negative electrode active material layer 200 are both 0 mm to 20 mm.

[0037] It can be understood that the two ends of the negative electrode active material layer 200 refer to the two ends in the length direction of the negative electrode active material layer 200, which can be defined as the starting end of the negative electrode active material layer 200 and the ending end of the negative electrode active material layer 200, respectively. Similarly, the two ends of the continuous line groove 210 refer to the two ends in the length direction of the negative electrode active material layer 200, which can be defined as the starting end of the continuous line groove 210 and the ending end of the continuous line groove 210, respectively. Since the distance between the two ends of the continuous line groove 210 and the two ends of the negative electrode active material layer 200 is 0mm~20mm, the distance between the starting end of the continuous line groove 210 and the starting end of the negative electrode active material layer 200 is 0mm~20mm, and the distance between the ending end of the continuous line groove 210 and the ending end of the negative electrode active material layer 200 is 0mm~20mm, thereby ensuring that the distribution of the continuous line groove 210 in the length direction of the negative electrode active material layer 200 is more appropriate, and more comprehensively preventing the edge of the battery negative electrode sheet 10 from lithium plating. Specifically, those skilled in the art can select according to actual needs, which may be 0mm, 1mm, 3mm, 0mm, 3mm, 5mm, 10mm, 12mm, 15mm, 16mm, 20mm, etc. Therefore, it is not specifically limited in the present disclosure.

[0038] In one of the more preferred embodiments, when the distance between the two ends of the continuous groove 210 and the two ends of the negative electrode active material layer 200 is 0 mm, the starting end of the continuous groove 210 is flush with the starting end of the negative electrode active material layer 200, and the ending end of the continuous groove 210 is flush with the ending end of the negative electrode active material layer 200, so that the continuous groove 210 can extend continuously from the starting end of the negative electrode active material layer 200 to the ending end of the negative electrode active material layer 200. In this way, it is ensured that the continuous groove 210 can be fully distributed in the length direction of the negative electrode active material layer 200, so as to ensure that the continuous groove 210 is distributed at each position in the length direction of the negative electrode active material layer 200, thereby more comprehensively preventing the edge of the battery negative electrode sheet 10 from easily depositing lithium.

[0039] like Figure 1 and Figure 2 As shown, in one embodiment, each of the continuous line grooves 210 is evenly distributed along the width direction of the negative electrode active material layer 200 to ensure that the n continuous line grooves 210 can be evenly distributed in the negative electrode active material layer 200, thereby ensuring that the n continuous line grooves 210 can evenly and more comprehensively prevent the edge of the battery negative electrode sheet 10 from serious lithium deposition.

[0040] In one embodiment, the continuous line groove 210 is a continuous laser line groove. It can be understood that since the laser generator has the characteristics of low power, high speed and accurate positioning, it can ensure that the laser generator can form a continuous laser line groove in the negative electrode active material layer 200 more accurately and quickly, effectively avoiding the phenomenon that the traditional use of a cutter causes inaccurate positioning and damages the negative electrode active material layer 200, thereby deteriorating the electrochemical performance of the lithium-ion battery. In addition, the continuous laser line groove not only reduces the processing difficulty, but also better ensures the uniformity of multiple continuous line grooves 210, and is not prone to misalignment.

[0041] In a preferred embodiment, the width of the edge zone is 0.5mm to 5mm. It can be understood that in order to ensure that the battery negative electrode sheet 10 has a higher energy density, if the width of the edge zone is greater than 5mm, it is easy to cause the edge zone to account for a large proportion of the current collector 100 to affect the overall energy density of the battery negative electrode sheet 10; if the width of the edge zone is less than 0.5mm, the width of the edge zone is narrower, which is not able to better ensure the dynamics of the edge of the negative electrode sheet, and is not conducive to processing. Therefore, in the present disclosure, by setting the width of the edge zone to 0.5mm to 5mm, it is ensured that the proportion of the edge zone in the current collector 100 is relatively appropriate, and the volume utilization rate of the battery negative electrode sheet 10 and the energy density of the battery cell will not be reduced while satisfying the premise of improving the lithium deposition at the edge of the battery negative electrode sheet 10, and it is also convenient for processing.

[0042] In one embodiment, the spacing between the continuous grooves 210 is 0.5 mm to 3 mm, so as to ensure that the spacing between the multiple continuous grooves 210 in the edge area is more appropriate, especially when the width of the edge area is 0.5 mm to 5 mm. In this way, while ensuring good dynamics at the edge of the negative electrode sheet, it is also easy to process and effectively avoids the phenomenon that the narrow spacing between each two adjacent continuous grooves 210 causes serious damage to the active materials in the edge areas on both sides of the negative electrode active material layer 200.

[0043] In one of the embodiments, the number of n is 1≤n≤5. It can be understood that if the number of n is greater than 5, the distribution of the multiple continuous linear grooves 210 in the edge area is denser, which can easily cause serious damage to the active material of the negative electrode active material layer 200. Therefore, in the present disclosure, by setting the number of n to 1≤n≤5, it is ensured that the distribution of the multiple continuous linear grooves 210 in the edge area is more appropriate, especially with the use of the edge area width of 0.5mm~5mm and the spacing of the continuous linear grooves 210 of 0.5mm~3mm. Under the premise of improving the lithium deposition at the edge of the battery negative electrode sheet 10, the volume utilization rate of the battery negative electrode sheet 10 and the energy density of the battery cell will not be reduced, and it is also easy to process, effectively avoiding the phenomenon that the large number of continuous linear grooves 210 causes serious damage to the active materials in the edge areas on both sides of the negative electrode active material layer 200.

[0044] like Figure 1 and Figure 3 As shown, in one embodiment, the continuous linear groove 210 is in the form of a continuous curve or a continuous straight line to ensure that the continuous linear groove 210 can be continuously distributed in the length direction of the negative electrode active material layer 200, thereby ensuring that the edge areas on both sides of the negative electrode active material layer 200 have better dynamics, effectively improving the phenomenon of lithium deposition at the edge of the negative electrode sheet.

[0045] like Figure 1 As shown, in a preferred embodiment, when the continuous linear groove 210 is in the form of a continuous straight line, the depth of the continuous linear groove 210 is 5 μm to 30 μm, and the width of the continuous linear groove 210 is 10 μm to 200 μm, so as to ensure that the linear continuous linear groove 210 is appropriately distributed on both side edge areas of the negative electrode active material layer 200.

[0046] like Figure 3 and Figure 4 As shown, in a preferred embodiment, when the continuous linear groove 210 is in the shape of a continuous curve, the depth of the continuous linear groove 210 is 5 μm to 30 μm, and the diameter of the continuous linear groove 210 is 20 μm to 500 μm, so as to ensure that the curved continuous linear groove 210 is more appropriately distributed on both side edge areas of the negative electrode active material layer 200.

[0047] Of course, the continuous wire groove 210 may also be in other shapes, such as a V-shape, and those skilled in the art may select the shape according to actual needs. Therefore, in the present disclosure, no specific limitation is made.

[0048] The present disclosure also provides a lithium-ion battery, comprising the battery negative electrode sheet 10 described in any of the above embodiments.

[0049] In one embodiment, a lithium-ion battery comprises a battery cell and a shell, wherein the battery cell is located in the shell, and the battery cell comprises a positive battery plate, a negative battery plate 10 and a separator, wherein the positive battery plate, the separator and the negative battery plate 10 are stacked in sequence, and the width of the negative battery plate 10 is greater than the width of the positive battery plate, so that the edges on both sides of the negative battery plate 10 can well receive the lithium ions of the positive battery plate, that is, ensure that the lithium ions on the negative battery plate 10 can migrate to the remaining part of the negative battery plate 10, so that the design of the negative battery plate 10 does not need to increase the amount of active material loss due to etching, thereby not reducing the volume utilization of the negative battery plate 10 and the energy density of the lithium-ion battery.

[0050] Compared with the prior art, the utility model has at least the following advantages:

[0051] Since at least n continuous linear grooves 210 are formed on the edge areas on both sides in the width direction of the negative electrode active material layer 200, and each of the continuous linear grooves 210 is arranged along the length direction of the negative electrode active material layer 200, it is ensured that the continuous linear grooves 210 are evenly distributed in the length direction of the negative electrode active material layer 200, thereby ensuring that the dynamics of the edge of the negative electrode sheet is good, effectively reducing the problem of lithium deposition at the edge of the battery negative electrode sheet 10, and greatly improving the lithium deposition phenomenon at the edge of the battery negative electrode sheet 10. Since the lines are only drawn on the edges of the two sides of the battery negative electrode sheet 10, and the width of the battery negative electrode sheet 10 is greater than the width of the battery positive electrode sheet, the battery negative electrode sheet 10 exceeds the battery positive electrode sheet. The width of the positive electrode sheet of the battery can receive a portion of the lithium ions transferred from the positive electrode sheet of the battery, and ensure that there is no continuous linear groove 210 in the middle part of the width direction of the negative electrode active material layer 200, thereby ensuring that the active material in the middle part of the negative electrode active material layer 200 will not be destroyed, and the loss of active material will be effectively reduced. In this way, while satisfying the premise of improving the lithium plating at the edge of the negative electrode sheet of the battery, the loss of active material can also be effectively reduced, thereby ensuring that the user does not need to increase the amount of coated active material, thereby ensuring that the thickness of the rolled negative electrode sheet of the battery will not increase, and thereby will not reduce the volume utilization rate of the negative electrode sheet 10 of the battery and the energy density of the battery cell.

[0052] The above-mentioned embodiments only express several implementation methods of the utility model, and the description is relatively specific and detailed, but it cannot be understood as limiting the scope of the utility model patent. It should be pointed out that for ordinary technicians in this field, several modifications and improvements can be made without departing from the concept of the utility model, which all belong to the protection scope of the utility model. Therefore, the protection scope of the utility model patent shall be based on the attached claims.

Claims

1. A battery negative electrode sheet, comprising a negative electrode current collector and a negative electrode active material layer, wherein the negative electrode active material layer is disposed on the negative electrode current collector, characterized in that: At least n continuous linear grooves are respectively formed on both side edge regions in the width direction of the negative electrode active material layer, where n is a positive integer, and each of the continuous linear grooves is arranged along the length direction of the negative electrode active material layer.

2. The battery negative electrode sheet according to claim 1, characterized in that: The distances between the two ends of the continuous linear groove and the two ends of the negative electrode active material layer are both 0 mm to 20 mm.

3. The battery negative electrode sheet according to claim 1, characterized in that: The continuous linear grooves are evenly distributed along the width direction of the negative electrode active material layer.

4. The battery negative electrode sheet according to claim 1, characterized in that: The continuous linear groove is a continuous laser linear groove.

5. The battery negative electrode sheet according to claim 1, characterized in that: The width of the edge area is 0.5 mm to 5 mm.

6. The battery negative electrode sheet according to claim 1, characterized in that: The spacing between the continuous wire grooves is 0.5 mm to 3 mm.

7. The battery negative electrode sheet according to claim 1, characterized in that: The number of n is 1≤n≤5.

8. The battery negative electrode sheet according to claim 1, characterized in that: The continuous wire groove is in the form of a continuous curve or a continuous straight line.

9. The battery negative electrode sheet according to claim 8, characterized in that: When the continuous groove is in the form of a continuous straight line, the depth of the continuous groove is 5 μm to 30 μm, and the width of the continuous groove is 10 μm to 200 μm; and / or, When the continuous linear groove is in the shape of a continuous curve, the depth of the continuous linear groove is 5 μm to 30 μm, and the diameter of the continuous linear groove is 20 μm to 500 μm.

10. A lithium ion battery, characterized in that: A battery negative electrode sheet comprising any one of claims 1-9.

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