Electrode sheet and battery

Abstract

The present invention provides an electrode sheet and a battery. The electrode sheet according to the present invention includes a current collector and an active material layer, the current collector includes a first segment, at least one surface of the first segment is distributed with a first coating region, a second coating region and a groove region, the second coating region includes a transition region, the transition region is located between the groove region and the edge of the current collector in the width direction of the current collector, the active material layer is attached to the current collector surface in the first coating region and the second coating region, and the thickness of the active material layer in the second coating region is smaller than the thickness of the active material layer in the first coating region. The present invention solves at least the technical problem that the electrode sheet is easily broken.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to a Chinese patent application filed with the China Patent Office on November 4, 2021, bearing application number 202122693996.7 and entitled "Electrode Sheet and Battery," the entire contents of which are incorporated herein by reference.

[0002] The present invention relates to the technical field of batteries, and more particularly to an electrode sheet and a battery. [Background technology]

[0003] Lithium batteries, as an environmentally friendly green energy source, have been rapidly developed in recent years. At the same time, consumer demands for the performance of lithium batteries are also increasing, and lithium batteries are required not only to have high capacity but also to meet the demands for charge and discharge rates.

[0004] In lithium batteries, connecting a tab to the middle of an electrode sheet can reduce the battery's internal resistance and temperature rise, thereby increasing the battery's charge / discharge rate. However, because an active material layer is coated on the current collector at the middle of the electrode sheet, the active material layer on the current collector must be washed away before connecting the tab. In related art, the active material and current collector at the edge of the groove where the tab is to be welded are cut together to form a notched groove in the electrode sheet. However, the cutting process in the conventional art is prone to tearing the electrode sheet, which affects the quality of the processed battery.

[0005] Therefore, there is an urgent need to develop an electrode sheet and a battery that can solve the technical problem of the electrode sheet being prone to breakage. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides an electrode sheet and a battery for solving at least the technical problem that the electrode sheet is prone to breakage. [Means for solving the problem]

[0007] To achieve the above object, the present invention provides an electrode sheet. The electrode sheet includes a current collector and an active material layer. The current collector includes a first segment, and a first coating region, a second coating region, and a groove region are distributed on at least one surface of the first segment. The second coating region includes a transition region, and the transition region is located between the groove region and the edge of the current collector in the width direction of the current collector. The active material layer is attached to the surface of the current collector in the first coating region and the second coating region, and the thickness of the active material layer in the second coating region is smaller than the thickness of the active material layer in the first coating region.

[0008] The electrode sheet according to the present invention includes the first coating region, the second coating region, and the groove region for welding the tab. The second coating region includes a transition region located between the groove region and the edge of the current collector, and the thickness of the active material layer in the second coating region is smaller than the thickness of the active material layer in the first coating region. This structure eliminates the need to trim the tip of the groove region during cutting, as in conventional techniques. Instead, the cutting position can be located in the wider transition region when cutting the electrode sheet. This prevents the groove region from being cut, reduces the difficulty of cutting, and effectively solves the problem of electrode sheet breakage, thereby preventing the impact of electrode sheet breakage on battery safety. Furthermore, the provision of the second coating region with a smaller thickness effectively eliminates the phenomenon of uneven electrode sheet thickness caused by tab welding after tab welding. This results in a uniform thickness for the final wound cell, which ultimately reduces the volume of the manufactured battery and increases the battery's energy density.

[0009] In one possible embodiment, the first application area extends to the longitudinal and widthwise edges of the first segment, and the groove area and the second application area are both located in the longitudinal center of the first application area.

[0010] In one possible embodiment, the ratio of the length of the groove region to the length of the transition region in the longitudinal direction of the current collector has a value S, where 5≧S≧1.

[0011] In one possible embodiment, the width of the transition region in the width direction of the current collector is 2 mm or more and 5 mm or less; and / or In the width direction of the current collector, the width of the groove region is 9 mm or more and 30 mm or less.

[0012] In one possible embodiment, the second coating region further includes an excess region, the excess region facing the transition region in the width direction of the current collector, and the width of the excess region is 0 mm or more and 5 mm or less.

[0013] In one possible embodiment, the first coating area, the second coating area, and the groove area are distributed on both sides of the first segment, and the first coating area, the second coating area, and the groove area are distributed at corresponding positions on both sides of the first segment.

[0014] In one possible embodiment, the active material layers in the second coating regions on both sides of the current collector have the same surface shape, or The active material layers in the second coating regions on both sides of the current collector have different surface shapes.

[0015] In one possible embodiment, the surface of the active material layer in the second coating region is flat, wavy, or inclined.

[0016] In one possible embodiment, the electrode sheet further includes a tab, the tab including a connecting segment and an extending segment that are connected to each other, the connecting segment being fixedly connected to one of the groove regions on both sides of the current collector, and the extending segment extending to outside the first coating region along the width direction of the current collector.

[0017] In one possible embodiment, the thickness of the active material layer applied to the first application area is 20 μm or more and 200 μm or less; and / or The thickness of the active material layer attached to the second coating region is 0 μm. Bigger and is 200 μm or less, and / or The thickness of the tab is not less than 100 μm and not more than 500 μm.

[0018] The present invention further provides a battery including a case and a cell housed in the case, the cell including a positive electrode sheet, a negative electrode sheet, and a separator interposed between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet, the negative electrode sheet, and the separator being stacked and wound, and at least one of the positive electrode sheet and the negative electrode sheet being the above-mentioned electrode sheet. [Effects of the Invention]

[0019] In the electrode sheet according to the present invention, the second coating area is provided, and the thickness of the active material layer in the second coating area is smaller than the thickness of the active material layer in the first coating area. This effectively prevents the phenomenon of uneven thickness of the electrode sheet due to tab welding after the tab is welded, and as a result, the volume of the manufactured battery can be reduced and the energy density of the battery can be increased.

[0020] In the electrode sheet and battery according to the present invention, the groove region and the second coating region are both located at the longitudinal center of the first coating region, and after processing a battery using this electrode sheet structure, the groove region can be used to weld tabs, facilitating parallel connection of the tabs, reducing the battery's supply current, reducing the battery's internal resistance, and reducing heat generation in the battery. As a result, less heat is generated during rapid charging or discharging, which is advantageous for improving the charge / discharge rate of the battery.

[0021] In addition to the problems to be solved by the above-mentioned embodiments of the present invention, the technical configurations constituting the technical solutions, and the beneficial effects of the technical configurations of these technical solutions, other technical problems that can be solved by the electrode sheets and batteries according to the embodiments of the present invention, other technical configurations included in the technical solutions, and the beneficial effects of these technical configurations will be described in more detail in specific embodiments. [Brief explanation of the drawings]

[0022] In order to more clearly explain the technical solutions in the embodiments of the present invention or the prior art, the following briefly introduces the drawings necessary for explaining the embodiments or the prior art. Obviously, the drawings described below are only some embodiments of the present invention, and those skilled in the art can obtain other drawings based on these drawings without paying creative labor. [Figure 1] 1 is a structural schematic diagram of an electrode sheet according to an embodiment of the present invention; [Figure 2] 2 is a structural schematic diagram of the cross section AA in FIG. 1 of the electrode sheet according to the embodiment of the present invention. [Figure 3] FIG. 2 is another structural schematic diagram of an electrode sheet according to an embodiment of the present invention. [Figure 4] 4 is a structural schematic diagram of the cross section BB in FIG. 3 of the electrode sheet according to the embodiment of the present invention. [Figure 5] 1 is a schematic diagram illustrating the structure of an electrode sheet raw material according to an embodiment of the present invention; [Figure 6] 6 is a structural schematic diagram of the cross section CC of FIG. 5 of the electrode sheet raw material according to the embodiment of the present invention. [Figure 7]6 is another structural schematic diagram of the electrode sheet raw material according to the embodiment of the present invention, taken along the CC cross section of FIG. 5. FIG. [Figure 8] 6 is another structural schematic diagram of the electrode sheet raw material according to the embodiment of the present invention, taken along the CC cross section of FIG. 5. FIG. [Figure 9] 6 is another structural schematic diagram of the electrode sheet raw material according to the embodiment of the present invention, taken along the CC cross section of FIG. 5. FIG. [Figure 10] 6 is another structural schematic diagram of the electrode sheet raw material according to the embodiment of the present invention, taken along the CC cross section of FIG. 5. FIG. DETAILED DESCRIPTION OF THE INVENTION

[0023] In order to clarify the objectives, technical solutions and advantages of the present invention, the technical solutions of the present invention will be described clearly and completely below with reference to the drawings in the present invention. Obviously, the described embodiments are only some of the embodiments of the present invention, but not all of the embodiments. Based on the embodiments in the present invention, any other embodiments obtained by those skilled in the art without any creative work fall within the scope of protection of the present invention.

[0024] In battery construction, tabs are typically welded near the edges of electrode sheets, and after the battery is fabricated, multiple tabs are connected in series. This increases the battery's internal resistance and heat generation, affecting the battery's application in fast charging applications. To alleviate the problems of internal resistance and temperature rise, tabs can be welded near the center of the electrode sheets and connected in parallel. This reduces the battery's internal resistance and heat generation, which is advantageous for improving the battery's charge / discharge rate.

[0025] However, welding the tab near the center of the electrode sheet tends to result in uneven thickness distribution of the electrode sheet, which affects the flatness of the final wound cell and leads to an increase in battery thickness. To improve the thickness distribution of the electrode sheet, related art involves cutting out the active material and current collector together at the position where the tab is to be welded in the electrode sheet, creating a groove with a single notch for welding the tab. This structure is prone to problems such as electrode sheet breakage due to misalignment of the cutting line caused by cutting errors during the electrode sheet cutting process, which affects the safety of battery use.

[0026] In view of this background, in the electrode sheet and battery according to the present invention, the structure of the electrode sheet is improved to provide a first coating area, a second coating area, and a groove area for welding a tab, and the transition area of ​​the second coating area is in contact with the groove area. current collector and the thickness of the active material layer in the second coating region is smaller than the thickness of the active material layer in the first coating region. This structure eliminates the need to cut the edges of the groove region, effectively solving the problem of the electrode sheet breaking when cutting the electrode sheet, and avoiding poor processing of the electrode sheet that could affect the safety of the battery.

[0027] Hereinafter, an electrode sheet and a battery according to an embodiment of the present invention will be described with reference to the drawings.

[0028] As shown in Figures 1 and 2, the present invention provides an electrode sheet, which includes a current collector 10 and an active material layer 20, and the current collector 10 includes a first segment 11, and a first coating area 31, a second coating area 32, and a groove area 33 are distributed on at least one surface of the first segment 11.

[0029] 1, the current collector 10 is in a sheet shape, and the direction indicated by X is the longitudinal direction of the first coating area 31, i.e., the longitudinal direction of the current collector 10, and the direction indicated by Y is the width direction of the first coating area 31, i.e., the width direction of the current collector 10. The first coating area 31 extends to the edges of the first segment 11 in the longitudinal and width directions, i.e., the length of the first coating area 31 is equal to the length of the first segment 11, and the width of the first coating area 31 is equal to the width of the first segment 11. In a specific example, In the longitudinal direction of the current collector 10, Both ends of the groove region 33 and both ends of the second coating region 32 contact the first coating region 31, respectively.

[0030] As shown in FIGS. 1 and 2, the second coating region 32 includes a transition region 321, and the transition region 321 is located between the groove region 33 and the edge of the current collector 10 in the width direction of the current collector 10.

[0031] No active material layer 20 is attached to the surface of the current collector 10 in any of the groove regions 33. The active material layer 20 is attached to the surface of the current collector 10 in the first coating region 31 and the second coating region 32, and the thickness of the active material layer 20 in the second coating region 32 is smaller than the thickness of the active material layer 20 in the first coating region 31.

[0032] The electrode sheet according to the present invention has a first coating area 31, a second coating area 32, and a groove area 33. As shown in Figures 3 and 4, the groove area 33 is used for welding the tab 50, and the second coating area 32 includes a transition area 321 that is located between the groove area 33 and the edge of the current collector 10. This structure eliminates the need to cut off the tip of the groove area 33, effectively solving the problem of the electrode sheet breaking when cutting the electrode sheet, and avoiding processing defects in the electrode sheet that could affect the safety of the battery.

[0033] In the electrode sheet according to the present invention, the thickness of the active material layer 20 in the second coating region 32 is smaller than the thickness of the active material layer 20 in the first coating region 31, and the second coating region 32 is provided. Therefore, after the tab 50 is welded to the groove region 33, the phenomenon of uneven thickness of the electrode sheet caused by the welding of the tab 50 can be effectively eliminated. This is advantageous in improving the flatness problem of the cell surface caused by the electrode sheet structure, and as a result, the energy density of the battery can be increased.

[0034] 1 and 3, in one possible embodiment, the groove area 33 and the second coating area 32 are both located in the longitudinal center of the first coating area 31. With this electrode sheet structure, after processing into a battery, the groove area 33 is used to weld the tabs 50, which makes it easier to realize parallel connection of the tabs 50, reduces the battery's supply current, reduces the battery's internal resistance, and reduces heat generation in the battery, which is beneficial to reducing heat generation during charging and discharging and improving the battery's charge and discharge rate.

[0035] In one possible embodiment, the ratio S of the length of the groove region 33 to the length of the transition region 321 along the longitudinal direction of the current collector 10 is 5≧S≧1. The groove region 33 may be slightly longer than the transition region 321 to ensure sufficient space for welding the tab 50 within the groove region 33. Furthermore, by setting the ratio S of the length of the groove region 33 to the length of the transition region 321 to 5 or less, it is possible to prevent the groove region 33 from being too long and affecting the energy density of the battery. Here, the longitudinal direction of the groove region 33 and the longitudinal direction of the transition region 321 coincide with the longitudinal direction of the current collector 10.

[0036] In one possible embodiment, the ratio S of the length of the groove region 33 to the length of the transition region 321 in the longitudinal direction of the current collector 10 may be 1, 2, 3, 4 or 5.

[0037] In one possible embodiment, the width of the transition region 321 in the width direction of the current collector 10 is 2 mm to 5 mm. direction Both directions coincide with the width direction of the current collector 10.

[0038] In one possible embodiment, the width of the transition region 321 in the width direction of the current collector 10 may be 2 mm, 3 mm, 4 mm or 5 mm.

[0039] In one possible embodiment, the width of the groove region 33 in the width direction of the current collector 10 is 9 mm to 30 mm.

[0040] In one possible embodiment, the width of the groove region 33 in the width direction of the current collector 10 may be 9 mm, 10 mm, 15 mm, 20 mm, 25 mm or 30 mm.

[0041] To ensure the welding effect of the tab 50, the active material layer 20 is not attached to the surface of the current collector 10 in the groove region 33. To ensure sufficient space for welding the tab 50 in the groove region 33, the length of the groove region 33 is made greater than the width of the tab 50. For example, the length of the groove region 33 may be 12 mm, the width of the tab 50 may be 4 mm, 5 mm, or 6 mm, and the length of the transition region 321 may be the same as the width of the tab 50, i.e., 4 mm, 5 mm, or 6 mm. In this way, when welding the tab 50 to the groove region 33, a sufficient safety distance can be ensured to avoid welding the tab 50 to a position where the active material layer 20 is attached.

[0042] 1 and 3, the second coating region 32 further includes an excess region 322, which is opposite the transition region 321 in the width direction of the current collector 10 and has a width of 0 mm to 5 mm.

[0043] In one possible embodiment, the electrode sheet may include an excess area 322, and the width of the excess area 322 may be 1 mm, 2 mm, 3 mm, 4 mm, or 5 mm. Of course, the electrode sheet may not include the excess area 322, i.e., the width of the excess area 322 may be 0 mm. Whether the electrode sheet includes the excess area 322 depends on the cutting position of the cutting line 60.

[0044] In the longitudinal direction of the current collector 10, The length of the excess region 322 may be equal to the length of the transition region 321. Before the electrode sheet is cut, the excess region 322 of one electrode sheet and the transition region 321 of another adjacent electrode sheet are connected together, and after the electrode sheet is cut, the excess region 322 of one electrode sheet and the transition region 321 of another adjacent electrode sheet are cut apart. In this way, the cutting and manufacturing efficiency of the electrode sheet is further improved, and the energy density of the battery in which the electrode sheet is installed is ensured.

[0045] 1 and 6, the active material layer 20 is adhered to the surface of the current collector 10 in the excess region 322 without omission. The excess region 322 and the transition region 321 are both located at the center of the first coating region 31 in the longitudinal direction, and the excess region 322 and the transition region 321 are located at the same position in the longitudinal direction of the first coating region 31. The excess region 322 and the transition region 321 may be located opposite each other in the width direction of the first coating region 31, and the excess region 322 and the transition region 321 may be located at both ends in the width direction of the first coating region 31.

[0046] In one possible embodiment, as shown in Figures 3 and 4, the above-mentioned electrode sheet further includes a tab 50, which includes a connecting segment 51 and an extending segment 52 connected to each other, the connecting segment 51 being fixedly connected to the groove region 33, and the extending segment 52 extending along the width direction of the current collector 10 through the transition region 321 to the outside of the first coating region 31.

[0047] In one possible embodiment, the connection segment 51 is welded to the groove area 33. The connection between the tab 50 and the groove area 33 can be realized by laser welding.

[0048] The extension segment 52 is a portion connected to the connection segment 51, and protrudes from the side edge of the electrode sheet to be connected to the positive or negative terminal of the battery. The extension segment 52 may extend through the transition region 321 to the outside of the first application region 31, and may extend to the outside of the first application region 31 so as to be in close contact with the surface of the transition region 321.

[0049] In one possible embodiment, the thickness of the extension segment 52 and the thickness of the active material layer 20 applied in the transition region 321 are overlapped, and are equal to or less than the thickness of the active material layer 20 in the first application region 31. This prevents the welding of the tab 50 from locally increasing the thickness of the electrode sheet, making the thickness distribution of the electrode sheet uniform. This is advantageous in improving the flatness of the cell surface caused by the electrode sheet structure after the electrode sheet is wound around the cell, and in preventing the cell volume from increasing and affecting the energy density of the battery.

[0050] In one possible embodiment, after the thickness of the extension segment 52 and the thickness of the active material layer 20 applied in the transition region 321 are superimposed, the thickness is greater than the thickness of the active material layer 20 in the first application region 31, but the thickness of the active material layer 20 in the transition region 321 is smaller than the thickness of the active material layer 20 in the first application region 31. Therefore, even with this structure, compared to an electrode sheet structure not provided with a transition region 321, it is advantageous for uniform distribution of the thickness of the electrode sheet after welding of the tab 50, and for an electrode sheet structure not provided with a transition region 321, it can avoid the problem of electrode sheet breakage and can reduce the thickness of the cell produced by winding the electrode sheet to a certain extent, thereby avoiding adverse effects on the energy density of the battery.

[0051] In one possible embodiment, the first segment 11 has a first coating area 31, a second coating area 32 and a groove area 33 distributed on one side thereof, and the other side of the first segment 11 is entirely the first coating area 31 (not shown in the figures).

[0052] 1 and 6, in one possible embodiment, the first segment 11 has a first coating area 31, a second coating area 32, and a groove area 33 distributed on both sides thereof, and the first coating area 31, the second coating area 32, and the groove area 33 are distributed at corresponding positions on both sides of the first segment 11. With this structure, the corresponding positions on the back side of the groove area 33 are also groove areas 33, which can reduce stress on the electrode sheet when welding the tab 50.

[0053] 3 and 4, the tab 50 is connected to one of the groove regions 33 on both sides of the current collector 10. For example, the connection segment 51 of the tab 50 and the groove region 33 on one side of the current collector may be welded together by laser welding.

[0054] In one possible embodiment, as shown in FIG. 2, the thickness of the active material layer 20 in the second coating region 32 exhibits a gradient distribution that gradually increases or gradually decreases along the width direction of the first coating region 31.

[0055] In one possible embodiment, as shown in FIG. 10, the thickness of the active material layer 20 in the second application region 32 is constant.

[0056] In one possible embodiment, the active material layer 20 in the second coating region 32 may first be uniformly coated and then removed in a gradient in the thickness direction of the second coating region 32 .

[0057] In one possible embodiment, as shown in FIG. 7, the surface of the active material layer 20 in the second application area 32 may be wavy, i.e., the active material layer 20 in the second application area 32 may be wavy block-shaped.

[0058] In one possible embodiment, as shown in FIG. 6, the surface of the active material layer 20 in the second application region 32 may be inclined, i.e., the active material layer 20 in the second application region 32 may be in the shape of a triangular block.

[0059] In one possible embodiment, as shown in FIG. 10, the surface of the active material layer 20 in the second application area 32 may be flat, i.e., the active material layer 20 in the second application area 32 may be in the shape of a rectangular block.

[0060] In one possible embodiment, the surface shapes of the active material layers 20 in the second coating regions 32 on both sides of the current collector 10 may be the same or different. That is, the shapes of the active material layers 20 in the second coating regions 32 distributed on both sides of the first segment 11 may be the same or different. For example, as shown in FIGS. 5 and 7, the active material layers 20 in the second coating regions 32 distributed on both sides of the first segment 11 may both have a rectangular block shape, or both have a wavy surface, or both have a sloped surface. As shown in FIGS. 8 and 9, the active material layers 20 in the second coating regions 32 distributed on one side of the first segment 11 may be rectangular block shapes, and the active material layers 20 in the second coating regions 32 distributed on the other side may have a wavy surface or a sloped surface.

[0061] The dimensions of the second coating area 32 and the groove area 33 in the electrode sheet can be adjusted depending on the size of the battery.

[0062] In this embodiment, there is no need to perform cutting around the groove area 33 where the tab 50 is welded, which avoids damage to the electrode sheet at the welding position of the tab 50 and reduces and improves the problems of electrode sheet breakage and tab failure at the groove position.

[0063] In one possible embodiment, the current collector 10 further includes a second segment 12 connected to at least one end of the first segment 11, and the surface of the second segment 12 does not have an active material layer 20 attached thereto.

[0064] In one possible embodiment, the electrode sheet may be a positive electrode sheet or a negative electrode sheet.

[0065] The materials of the current collectors 10 in the positive and negative electrode sheets can be selected according to actual needs and are not limited here. For example, the current collector 10 in the positive electrode sheet can be aluminum foil, and the current collector 10 in the negative electrode sheet can be copper foil.

[0066] The types and proportions of the active materials in the active material layers 20 of the positive and negative electrode sheets can also be set according to actual needs and are not further limited herein. For example, the active material in the active material layer 20 of the negative electrode sheet may include materials such as graphite, hard carbon, silicon, and silicon monoxide, and the active material in the active material layer 20 of the positive electrode sheet may include materials such as lithium cobalt oxide, lithium iron phosphate, and lithium manganese oxide.

[0067] As shown in Figure 5, the present invention further provides an electrode sheet raw web. The electrode sheet raw web includes the above-mentioned electrode sheets, and multiple electrode sheets are connected in sequence along the width direction of a current collector 10. A first segment 11 of an electrode sheet is connected to a first segment 11 of an adjacent electrode sheet, and a second segment 12 of an electrode sheet is connected to a second segment 12 of an adjacent electrode sheet.

[0068] The electrode sheet raw roll is the material used to process the electrode sheet, and to improve production efficiency, the electrode sheet is usually cut after an active material layer 20 is applied to the surface of the electrode sheet raw roll. In the electrode sheet cutting step, the electrode sheet raw roll is cut along cutting lines 60 on the electrode sheet raw roll to divide the electrode sheet raw roll into multiple electrode sheets. The cutting lines 60 are imaginary lines that extend along the longitudinal direction of the electrode sheet, and after cutting is complete, the electrode sheet raw rolls on both sides of the cutting line 60 become two independent electrode sheets.

[0069] In one possible embodiment, the excess area 322 of the second coating area 32 of one electrode sheet is connected to the transition area 321 of the second coating area 32 of an adjacent electrode sheet. With this structure, as shown in Figures 5 and 7, when cutting the electrode sheet, the cutting line 60 divides the second coating area 32 into the excess area 322 and the transition area 321, which are located on two different electrode sheets, and the active material layer 20 is applied to the surface of the current collector 10 in both the excess area 322 and the transition area 321. This prevents the surface of the current collector 10 from being exposed in parts other than the groove area 33 of the first segment 11 of the electrode sheet due to cutting errors in the original electrode sheet, thereby avoiding any impact on the quality and safety of the battery.

[0070] In one possible embodiment, the thickness of the active material layer 20 applied to the first application area 31 is 20 μm to 200 μm, and / or the thickness of the active material layer 20 applied to the second application area 32 is 0 μm to 200 μm.

[0071] For example, the active material layer 20 attached to the first coating region 31 may have an average thickness of 20 μm, and the active material layer 20 attached to the second coating region 32 may have an average thickness of 10 μm. Alternatively, the active material layer 20 attached to the first coating region 31 may have an average thickness of 100 μm, and the active material layer 20 attached to the second coating region 32 may have an average thickness of 50 μm or 80 μm. Alternatively, the active material layer 20 attached to the first coating region 31 may have an average thickness of 200 μm, and the active material layer 20 attached to the second coating region 32 may have an average thickness of 70 μm or 100 μm. The thickness of the active material layer 20 in the second coating region 32 must be smaller than the thickness of the active material layer 20 in the first coating region 31.

[0072] In one possible embodiment, the thickness of the tab 50 is between 100 μm and 500 μm. For example, the average thickness of the tab 50 may be 100 μm, 200 μm, 300 μm, 400 μm, or 500 μm.

[0073] In the electrode sheet raw material according to the present invention, as shown in FIG. 5 , the active material layer 20 is applied to both the surface of the current collector 10 in the transition region 321 and the excess region 322. Therefore, even if the cutting line 60 is shifted up or down along the width direction of the current collector 10 due to cutting errors, the result is that only the area of ​​the transition region 321 and the excess region 322 adjacent to the transition region 321 changes, and the current collector 10 in the excess region 322 is not exposed, and no notch is created at the position of the excess region 322. This reliably avoids the problem of the electrode sheet breaking.

[0074] The electrode sheet raw material may be cut by a sheet manufacturing machine or an integrated sheet manufacturing and winding machine, or the electrode sheet according to this embodiment may be processed by laser cutting.

[0075] The present invention further provides a battery comprising a case and a cell housed in the case, the cell including a positive electrode sheet, a negative electrode sheet, and a separator interposed between the positive electrode sheet and the negative electrode sheet, the positive electrode sheet, the negative electrode sheet, and the separator being stacked and wound, and at least one of the positive electrode sheet and the negative electrode sheet being the above-mentioned electrode sheet.

[0076] In the battery according to the present invention, the positive electrode sheet may be the above-described electrode sheet and the negative electrode sheet may be a normal electrode sheet, or the negative electrode sheet may be the above-described electrode sheet and the positive electrode sheet may be a normal electrode sheet, or of course, both the positive electrode sheet and the negative electrode sheet may be the above-described electrode sheet.

[0077] In the battery according to the present invention, since the above-described electrode sheet is used, the cell surface has excellent flatness, and the stress experienced by the surface of the electrode sheet during the cycle charge / discharge process of the battery is uniform, which is advantageous in improving the service life of the battery and the charge / discharge rate of the battery.

[0078] The separator separates the positive electrode sheet from the negative electrode sheet, preventing them from coming into contact with each other and causing a short circuit, and also allows electrolyte ions in the electrolyte to pass through.

[0079] The separator may include a substrate and a coating layer, where the substrate may be a polyethylene (PE) monolayer film, a polypropylene (PP) monolayer film, or a polypropylene-polyethylene-polypropylene three-layer composite film, and the coating layer may be at least one of porous silica, aluminum oxide, titanium dioxide, and zirconium dioxide.

[0080] The case is further filled with an electrolyte, and the cell is immersed in the electrolyte.

[0081] In one possible embodiment, the cells described above may be cells of wound construction.

[0082] In one possible embodiment, the above-mentioned battery may be a pouch battery, an aluminum shell battery or a cylindrical battery.

[0083] In addition, in the description of the present invention, the directions or positional relationships indicated by the terms used, such as "center," "length," "width," "thickness," "tip," "bottom end," "upper," "lower," "left," "right," "front," "rear," "vertical," "horizontal," "inner," "outer," "axial direction," and "circumferential direction," are based on the orientations or positional relationships shown in the drawings, and are merely intended to simplify the description and explanation of the present invention. They do not necessarily indicate or imply that such positions or elements necessarily have a specific orientation or a specific structure and operation, and therefore should not be understood as limitations on the present invention.

[0084] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or the number of technical features shown. Thus, a "first" or "second" feature may explicitly or implicitly include one or more features. In the description of the present invention, "plurality" means at least two, e.g., two, three, etc., unless otherwise specified.

[0085] In the present invention, unless otherwise specified, the terms "attached," "connected," "connected," "fixed," etc. should be understood in a broad sense, and may refer to, for example, a fixed connection, a detachable connection, or integration, a mechanical connection, an electrical connection, or communication with each other, a direct connection, an indirect connection via an intermediate medium, internal communication between two elements, or an interactive relationship between two elements. Those skilled in the art will be able to understand the specific meaning of the above terms in the present invention according to specific circumstances.

[0086] In the present invention, unless otherwise specified, a first structure being "above" or "below" a second structure may include direct contact between the first and second structures, or may include contact between the first and second structures via another structure between them rather than direct contact. Furthermore, a first structure being "above," "above," and "on the upper surface" of a second structure may include the first structure being directly above and diagonally above the second structure, or may simply indicate that the horizontal height of the first structure is higher than that of the second structure. A first structure being "below," "below," and "below" a second structure may include the first structure being directly below and diagonally below the second structure, or may simply indicate that the horizontal height of the first structure is smaller than that of the second structure.

[0087] Finally, it should be noted that the above embodiments are only used to explain the technical solutions of the present invention, and are not intended to be limiting thereof. Although the present invention has been described in detail with reference to the above embodiments, those skilled in the art should understand that the technical solutions described in the above embodiments can be modified or some or all of the technical features can be replaced with equivalents, and such modifications or replacements do not deviate from the essence of the corresponding technical solutions and the scope of the technical solutions of the embodiments of the present invention. [Explanation of symbols]

[0088] 10-Current Collector 20-Active material layer 11-First Segment 12-Second Segment 31-First application area 32-Second application area 321-Transition area 322-Surplus Area 33-Groove area 50-tab 51-connection segment 52-Extended segment 60-Cutting Line

Claims

1. An electrode sheet, It includes a current collector (10) and an active material layer (20), The current collector (10) includes a first segment (11), and a first coating area (31), a second coating area (32), and a groove area (33) are distributed on at least one surface of the first segment (11); The second coating region (32) includes a transition region (321), and the transition region (321) is located between the groove region (33) and the edge of the current collector (10) in the width direction of the current collector (10); The active material layer (20) is attached to the surface of the current collector (10) in the first coating region (31) and the second coating region (32), the thickness of the active material layer (20) in the second coating region (32) is smaller than the thickness of the active material layer (20) in the first coating region (31); The second application area (32) further includes an excess area (322); In the width direction of the current collector (10), the excess region (322) and the transition region (321) are positioned opposite each other, and the width of the excess region (322) is greater than 0 mm and less than or equal to 5 mm; In the longitudinal direction of the current collector (10), the length of the excess region (322) is equal to the length of the transition region (321). An electrode sheet characterized by:

2. The first application area (31) extends to the longitudinal and widthwise edges of the first segment (11); The groove area (33) and the second coating area (32) are both located at the center of the first coating area (31) in the longitudinal direction.

2. The electrode sheet according to claim 1 .

3. In the longitudinal direction of the current collector (10), the ratio of the length of the groove region (33) to the length of the transition region (321) is S, where 5≧S≧1.

2. The electrode sheet according to claim 1 .

4. In the width direction of the current collector (10), the width of the transition region (321) is 2 mm or more and 5 mm or less; and / or 2. The electrode sheet according to claim 1, wherein the width of the groove region (33) in the width direction of the current collector (10) is 9 mm or more and 30 mm or less.

5. The first coating area (31), the second coating area (32) and the groove area (33) are distributed on both sides of the first segment (11); The first coating area (31), the second coating area (32) and the groove area (33) are distributed at positions corresponding to each other on both sides of the first segment (11).

2. The electrode sheet according to claim 1 .

6. The surface shape of the active material layer (20) in the second coating region (32) on both sides of the current collector (10) is the same, or The surface shapes of the active material layer (20) in the second coating region (32) on both sides of the current collector (10) are different.

6. The electrode sheet according to claim 5.

7. The surface of the active material layer (20) in the second coating region (32) is flat, wavy, or inclined.

2. The electrode sheet according to claim 1 .

8. further comprising a tab (50); The tab (50) includes a connecting segment (51) and an extending segment (52) connected to each other; The connection segment (51) is fixedly connected to one of the groove regions (33) on both sides of the current collector (10), and the extension segment (52) extends to the outside of the first coating region (31) along the width direction of the current collector (10). The electrode sheet according to any one of claims 1 to 7.

9. The thickness of the active material layer (20) applied to the first coating area (31) is 20 μm or more and 200 μm or less, and / or the thickness of the active material layer (20) applied to the second coating area (32) is greater than 0 μm and less than or equal to 200 μm; and / or 9. The electrode sheet according to claim 8, wherein the thickness of the tab (50) is 100 μm or more and 500 μm or less.

10. A battery including a case and a cell housed within the case, The cell includes a positive electrode sheet, a negative electrode sheet, and a separator interposed between the positive electrode sheet and the negative electrode sheet, and the positive electrode sheet, the negative electrode sheet, and the separator are stacked and wound; At least one of the positive electrode sheet and the negative electrode sheet is the electrode sheet according to any one of claims 1 to 7. A battery characterized by:

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