Current collector, electrode tab, battery, and electric device

Abstract

The application provides a current collector, an electrode pole piece, a battery and an electric device. The current collector is provided with a plurality of blind holes, and has a first surface and a second surface arranged oppositely, and the plurality of blind holes are distributed on the first surface and / or the second surface. The blind holes on the first surface or the second surface each include a first blind hole and a second blind hole. The aperture of the first blind hole is D1, and 50 μm≤D1≤100 μm. The aperture of the second blind hole is D2, and 10 μm≤D2≤30 μm. The current collector has high adhesion between the electrode material layer and the current collector, and can realize high electronic conductivity, so that the cycle performance and the rate performance of the battery can be improved.

Description

Technical Field

[0001] This application relates to the field of battery technology, specifically to current collectors, electrode sheets, batteries, and electrical devices. Background Technology

[0002] As a key component of secondary batteries, the current collector serves to support the electrode material layer and collect the current generated by the active materials in the electrode material for output, while also inputting the electrode current into the electrode material layer. An ideal current collector needs high electronic conductivity, superior mechanical properties, and strong adhesion to the electrode material layer. However, in practical applications, manufacturers often use foil materials (such as aluminum foil or copper foil) directly as current collectors. These current collectors have low bonding strength with the electrode material layer and high interfacial contact resistance, which affects battery performance.

[0003] To address these issues, porous current collectors have emerged. However, existing porous current collectors are generally obtained by creating through holes in foil materials, resulting in low mechanical strength and limited improvement in the bonding strength between the current collector and the electrode material layer, as well as the interfacial contact resistance of the current collector. Summary of the Invention

[0004] In view of this, embodiments of this application provide a current collector, an electrode sheet, a battery, and an electrical device. This current collector has a novel structure that exhibits both high adhesion to the electrode material layer and high electronic conductivity, thereby improving the battery's cycle performance and rate performance.

[0005] The first aspect of this application provides a current collector having a plurality of blind holes, the current collector having a first surface and a second surface disposed opposite to each other, the plurality of blind holes being distributed on the first surface and / or the second surface;

[0006] The blind hole on the first surface or the second surface includes a first blind hole and a second blind hole; wherein, the diameter of the first blind hole is D1, 50μm≤D1≤100μm; and the diameter of the second blind hole is D2, 10μm≤D2≤30μm.

[0007] The current collector surface has multiple blind holes, which enhances the adhesion between the current collector and the electrode material layer and accelerates electron conduction between them. More importantly, one side of the current collector also has a first blind hole with a larger aperture and a second blind hole with a relatively smaller aperture. The first blind hole has a aperture of 50μm-100μm, which can fill more electrode material, further enhancing the adhesion between the current collector and the electrode material layer. The second blind hole has a relatively smaller aperture and a larger specific surface area than the first blind hole, resulting in a larger contact area between the electrode material and the current collector, thus better accelerating electron conduction and reducing the interfacial impedance of the current collector. Therefore, the current collector has both a first blind hole and a second blind hole on one side. With their synergistic effect, this current collector can be used to provide an electrode sheet with both high peel strength and high electronic conductivity, thereby providing a battery with good cycle stability and superior rate performance.

[0008] Optionally, the plurality of blind holes are distributed on the first surface and the second surface, and along the thickness direction of the current collector, the orthographic projection of at least some of the blind holes on the first surface does not overlap with the orthographic projection of the blind holes on the second surface.

[0009] Optionally, based on the sum of the opening areas of the plurality of blind holes on the first surface, the sum of the areas of the blind holes on the first surface that do not overlap with the orthographic projections of the blind holes on the second surface is greater than 50%.

[0010] Optionally, on the first surface or the second surface, a plurality of second blind holes are provided around the periphery of each first blind hole; the ratio of the number of first blind holes to the number of second blind holes is in the range of 1:(2-8).

[0011] Optionally, the first surface or the second surface has a plurality of first blind hole groups, each first blind hole group including one first blind hole and two second blind holes adjacent to the first blind hole, and the line connecting the center of the first blind hole in the first blind hole group and the center of the two second blind holes forms a first triangle.

[0012] Furthermore, in the first triangle, the angles of the three angles are in the range of 15°-120°, wherein the angle located at the first blind hole is in the range of 15°-120°, and the angle located at the second blind hole is in the range of 15°-85°.

[0013] Furthermore, the first triangle is an isosceles triangle.

[0014] Optionally, in each of the first blind hole groups, the opening area of ​​the first blind hole accounts for a range of 2.0%-44.6%, and the opening area of ​​the second blind hole accounts for a range of 1.1%-8.9%.

[0015] Optionally, the first surface or the second surface has a plurality of second blind hole groups, each second blind hole group including three adjacent second blind holes and the first blind hole, and the line connecting the centers of the three second blind holes in the second blind hole group forms a second triangle, and the first blind hole in the second blind hole group is located in the second triangle;

[0016] The second triangle is an isosceles triangle.

[0017] Optionally, the side lengths of the second triangles are each independently in the range of 100μm-500μm.

[0018] Optionally, on the first surface or the second surface, the sum of the opening areas of the plurality of first blind holes and the plurality of second blind holes is 15.0%-78.5% of the surface area of ​​the first surface or the surface area of ​​the second surface.

[0019] Optionally, the depths of the first blind hole and the second blind hole are each independently 1.5%-50% of the thickness of the current collector.

[0020] Optionally, the ratio of the opening area of ​​each second blind hole to the opening area of ​​each first blind hole is 1:(0.01-0.6).

[0021] A second aspect of this application provides an electrode sheet, which includes the current collector provided in the first aspect of this application.

[0022] Because the current collector provided in this application is used, the electrode sheet has high peel strength and good structural stability during battery cycling, which is beneficial to improving the battery's cycle performance. At the same time, the electrode sheet also has high electronic conductivity and ionic conductivity, which can improve the rate performance of the final battery.

[0023] A third aspect of this application provides a battery comprising the electrode plates provided in the second aspect of this application. Due to the use of the aforementioned electrode plates, the battery exhibits both good cycle performance and rate performance, and can achieve higher energy density.

[0024] A fourth aspect of this application provides an electrical device that includes the battery provided in the third aspect of this application. The battery is used to power the electrical device. Due to the inclusion of the battery provided in the embodiments of this application, the electrical device has high market competitiveness. Attached Figure Description

[0025] Figure 1A A partial top view of a current collector provided in an embodiment of this application;

[0026] Figure 1B A cross-sectional view of a current collector provided in another embodiment of this application;

[0027] Figure 1C A partial top view of a current collector having a plurality of first blind orifice groups provided in an embodiment of this application;

[0028] Figure 2 A partial top view of a current collector having a plurality of second blind hole groups, provided for another embodiment of this application;

[0029] Figure 3 A partial top view of a current collector having a plurality of second blind hole groups, provided for another embodiment of this application.

[0030] Explanation of reference numerals: 100 - Current collector; 10 - First surface; 20 - Second surface; 30 - Blind hole; 31 - First blind hole; 32 - Second blind hole. Detailed Implementation

[0031] As a key component of secondary batteries, the current collector's structural characteristics and electrochemical properties affect battery performance. Current collectors can simultaneously perform multiple functions, such as supporting electrode material layers and collecting and transporting electrons. Improving the adhesion between the battery material layer and the current collector, and reducing the interfacial resistance of the current collector, facilitates its application in electrode plates and ultimately enhances the performance of the electrode plates.

[0032] Please see also Figures 1A-1C This application provides a current collector 100, which has a plurality of blind holes 30. The current collector 100 has a first surface 10 and a second surface 20 disposed opposite to each other, and the plurality of blind holes 30 are distributed on the first surface 10 and / or the second surface 20.

[0033] The blind hole 30 on the first surface 10 or the second surface 20 includes a first blind hole 31 and a second blind hole 32, wherein the diameter of the first blind hole 31 is D1, 50μm≤D1≤100μm; and the diameter of the second blind hole 32 is D2, 10μm≤D2≤30μm.

[0034] In this embodiment, the current collector has a first surface 10 and a second surface 20 disposed opposite to each other. In this embodiment, the first blind hole 31 and the second blind hole 32 may be distributed on the first surface 10 of the current collector, or the first blind hole 31 and the second blind hole 32 may be distributed on the second surface 20 of the current collector. Alternatively, the first blind hole 31 and the second blind hole 32 may be distributed on both the first surface 10 and the second surface 20 of the current collector. When the first blind hole 31 and the second blind hole 32 are distributed on both the first surface 10 and the second surface 20 of the current collector 100, the number of first blind holes 31 and the number of second blind holes 32 on the first surface 10 and the second surface 20 may be the same or different; the aperture of the first blind hole 31 and the aperture of the second blind hole 32 may be the same or different; the total number of blind holes 30 may be the same or different.

[0035] In this embodiment, a blind hole specifically refers to a non-through hole.

[0036] Understandably, the manufacturing process of electrode sheets generally includes: preparing electrode slurry (e.g., positive electrode slurry, negative electrode slurry), coating the electrode slurry onto the surface of the current collector, and filling the blind holes with the electrode slurry. After drying, this portion of the slurry can act as an "anchor" for the electrode material layer to extend into the current collector, thereby improving the adhesion between the electrode material layer and the current collector. At the same time, compared to planar foil, the direct contact area between the electrode slurry and the blind holes is larger under the same projected area, which can also help improve the adhesion between the electrode material layer and the current collector, thereby significantly improving the peel strength of the electrode sheet. More importantly, the current collector has both a first blind hole with a relatively large pore size and a second blind hole with a relatively small pore size dispersed on one side of its surface. The first blind hole has a pore size of 50μm-100μm, which can fill more electrode slurry. After the slurry solidifies, it can better act as an "anchor", which is more conducive to improving the adhesion between the current collector and the electrode material layer. The second blind hole has a smaller pore size and a larger specific surface area than the first blind hole. The contact area between the electrode material and the current collector is larger, which can better accelerate electron conduction and reduce the interfacial impedance of the current collector. Therefore, the current collector has both a first blind hole and a second blind hole on one side of its surface. With the synergistic effect of the two, the current collector can be used to provide an electrode sheet with both high peel strength and high electronic conductivity, which can be used to provide a battery with good cycle stability and superior rate performance.

[0037] Furthermore, compared to the through-hole current collectors commonly used in existing technologies, the depth of blind holes is significantly smaller than that of through holes when the current collector thickness is equal. When the electrode slurry coating speed is high, blind holes are more conducive to the filling of the electrode slurry (i.e., blind holes are easily filled by the electrode slurry), thereby improving the adhesion between the electrode material layer and the current collector and increasing the energy density of the battery. It is evident that using the current collector provided in this application embodiment can not only improve the peel strength of the electrode sheets and increase the final energy density of the battery, but also improve the production efficiency of the electrode sheets while ensuring good battery performance. Moreover, improving the adhesion between the current collector and the electrode material layer can also correspondingly improve the current collector's load-bearing capacity on the electrode material layer. Therefore, when the peel strength of the electrode sheets is equal, the current collector provided in this application embodiment can support a greater thickness of electrode material layer than existing technologies.

[0038] It is also understandable that the ductility of the current collector material is better than that of the electrode paste (electrode material layer). In the current collectors with through holes used in the prior art, the entire thickness of the current collector material is replaced by the poorly ductile electrode paste (electrode material layer material) at the through hole location. However, the holes in the current collector of this application are blind holes. Therefore, after coating its surface with electrode paste, the resulting electrode sheet has material with better ductility at any location, thereby improving the extensibility of the electrode sheet and reducing the breakage rate of the electrode sheet.

[0039] In this embodiment, the diameters of the first blind hole and the second blind hole refer to the diameters of their openings on the surface of the current collector, respectively. In this embodiment, the maximum cross-sectional dimension of the blind hole, pointing from its opening along its thickness direction toward the interior of the current collector, can be constant, gradually decreasing, or gradually increasing. Taking a blind hole on the first surface as an example, the diameter of the blind hole, pointing from its opening along its thickness direction toward the second surface of the current collector, can be uniform, gradually decreasing, or gradually increasing.

[0040] In this embodiment, the opening shapes of the first blind hole and the second blind hole can each be independently circular, elliptical, square, rectangular, prismatic, polygonal, etc. When the first blind hole and the second blind hole are circular, their diameters refer to the diameters of the openings of the first blind hole and the second blind hole, respectively. When the opening shapes of the first blind hole and the second blind hole are polygonal, their diameters refer to the diameters of the circumcircle of the polygon.

[0041] In this embodiment, the aperture D1 of the first blind hole can be, but is not limited to, 50μm, 52μm, 55μm, 58μm, 60μm, 62μm, 65μm, 68μm, 70μm, 72μm, 75μm, 78μm, 80μm, 82μm, 85μm, 88μm, 90μm, 92μm, 95μm, 98μm, 100μm, etc. If the aperture D1 of the first blind hole is too small (less than 50μm), the anchoring effect of the electrode material layer on the current collector cannot be guaranteed, and therefore, the peel strength of the final electrode sheet cannot be significantly improved. If the aperture D1 of the first blind hole is too large (greater than 100 μm), the binding force on the material inside the first blind hole from the sidewall of the blind hole will be weakened, which will also weaken its anchoring effect, thus affecting the peel strength of the electrode sheet. In addition, when the ratio of the opening area of ​​the blind hole to the surface area of ​​the current collector remains unchanged, if the aperture of the first blind hole is too large, the total number of blind holes will be too small, which is not conducive to the distribution of blind holes on the surface of the current collector, thus affecting the uniformity of the final electrode sheet.

[0042] In this embodiment, the aperture D2 of the second blind hole can be, but is not limited to, 10μm, 12μm, 15μm, 18μm, 20μm, 22μm, 25μm, 28μm, 30μm, etc. If the aperture D2 of the second blind hole is too small, it is not conducive to the filling of the electrode paste, thus failing to fully increase the contact area between the material and the current collector; if the aperture D2 of the second blind hole is too large, it will lead to a decrease in the specific surface area of ​​the second blind hole, which is also not conducive to fully increasing the contact area between the material and the current collector. Therefore, both excessively large and excessively small apertures of the second blind hole are not conducive to reducing the interfacial impedance of the current collector.

[0043] In the embodiments of this application, the aperture D1 of the first blind hole and the aperture D2 of the second blind hole can be characterized by an optical microscope or a scanning electron microscope (SEM).

[0044] In some embodiments of this application, the first blind hole and the second blind hole are distributed on the first surface and the second surface, respectively. That is, the first surface and the second surface of the current collector are respectively provided with a plurality of the aforementioned first blind holes and a plurality of second blind holes. In this way, the interfacial impedance of the current collector relative to the two sides of the surface can be reduced at the same time, and the adhesion between the current collector relative to the two sides of the surface and the electrode material layer can be improved, thereby further improving the peel strength of the final electrode sheet and further improving the cycle performance and rate performance of the final battery. In some specific embodiments, along the thickness direction of the current collector, at least some of the orthographic projections of the blind holes on the first surface do not overlap with the orthographic projections of the multiple blind holes on the second surface. The blind holes are recessed into the current collector relative to the first surface and the second surface of the current collector. Therefore, the thickness of the current collector in the area with blind holes will be relatively thin. By controlling that the orthographic projections of at least some of the blind holes on the first surface do not overlap with the orthographic projections of the blind holes on the second surface, the situation of a large area of ​​thin current collector can be avoided, thereby ensuring good mechanical properties of the current collector, which is beneficial to the preparation of the electrode sheet and also to ensuring the structural stability of the final electrode sheet, and thus beneficial to the performance of the final battery.

[0045] In some embodiments, the sum of the opening areas of the blind holes on the first and / or second surfaces is relatively small, ensuring that the orthographic projections of the multiple blind holes on the first surface and the multiple blind holes on the second surface do not overlap in the thickness direction of the current collector. This results in relatively better mechanical properties of the current collector. In other embodiments, the sum of the opening areas of the blind holes on the first and / or second surfaces is relatively large, and the orthographic projections of the blind holes on the first surface may overlap with the orthographic projections of the multiple blind holes on the second surface along the thickness direction of the current collector. In this case, based on the sum of the opening areas of the multiple blind holes on the first surface, the sum of the areas of the blind holes on the first surface that do not overlap with the orthographic projections of the blind holes on the second surface is ≥30% along the thickness direction of the current collector. This maximizes the bonding strength between the current collector and the electrode material layer, reduces the interfacial impedance of the current collector, and also ensures good mechanical properties of the current collector, enabling it to fully withstand the stress during battery cycling and guaranteeing good structural stability of the electrode sheet during battery cycling. For example, based on the sum of the opening areas of the plurality of blind holes on the first surface, the sum of the area ratios of the blind holes on the first surface that do not overlap with the orthographic projections of the blind holes on the second surface may be, but is not limited to, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 80%, 85%, 90%, 95%, etc.

[0046] In this embodiment, when the orthographic projection of a blind hole on the first surface overlaps with the orthographic projection of a blind hole on the second surface along the thickness direction of the current collector, the following situations are included, but are not limited to: (1) the orthographic projection of a blind hole on the first surface partially overlaps with the orthographic projection of a blind hole on the second surface; (2) the orthographic projection of a blind hole on the first surface overlaps with the orthographic projections of two or more blind holes on the second surface. Both of these situations are beneficial to ensuring good mechanical properties of the current collector.

[0047] In some embodiments of this application, on the first surface or the second surface, each first blind hole is surrounded by a plurality of second blind holes. That is, if the current collector has a plurality of blind holes only on the first surface, the plurality of blind holes on the first surface satisfy the above conditions. If the current collector has a plurality of blind holes on opposite sides, the blind holes on the first surface or the second surface satisfy the above conditions. Furthermore, the blind holes on both the first surface and the second surface satisfy the above conditions. The first blind holes are more conducive to improving the adhesion between the current collector and the electrode material layer, and the second blind holes are more conducive to reducing the interfacial impedance of the current collector. This arrangement is conducive to achieving the cooperation effect of the first blind holes and the second blind holes at different positions on one side of the current collector, which can improve the uniformity of the current collector and make the peel strength and electronic conductivity of the final electrode plate higher at different positions.

[0048] In some embodiments of this application, the ratio of the number of first blind holes to the number of second blind holes on the first surface or the second surface is in the range of 1:(2-8). If multiple first blind holes and second blind holes are arranged on opposite sides of the current collector, the blind holes on the first surface or the second surface satisfy the above conditions. Furthermore, the blind holes on both the first surface and the second surface satisfy the above conditions. A suitable ratio of the number of first blind holes to second blind holes is beneficial for balancing the interfacial impedance of the current collector and its adhesion to the electrode material layer, and also beneficial for homogenizing the ion conduction performance in the current collector, resulting in better overall performance of the current collector, and thus beneficial for balancing the electronic conductivity and anti-peeling performance of the final electrode sheet. Specifically, on each side surface of the current collector, the ratio of the number of first blind holes to the number of second blind holes can be 1:2, 1:2.5, 1:3, 1:3.5, 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5, 1:7, 1:7.5, 1:8, etc.

[0049] In some embodiments of this application, the ratio of the opening area of ​​each second blind hole to the opening area of ​​each first blind hole is 1:(0.01-0.6). Exemplarily, the ratio of the opening area of ​​each second blind hole to the opening area of ​​each first blind hole can be 1:0.01, 1:0.05, 1:0.10, 1:0.15, 1:0.20, 1:0.25, 1:0.30, 1:0.35, 1:0.40, 1:0.45, 1:0.50, 1:0.55, 1:0.60, etc. In some specific embodiments, the ratio of the opening area of ​​each second blind hole to the opening area of ​​each first blind hole is 1:(0.25-0.5), i.e. (2-4). This is more conducive to improving the bonding force between the current collector and the electrode material layer.

[0050] In this embodiment of the application, the opening area of ​​the first blind hole refers to the area of ​​the opening formed by the first blind hole on the surface of the current collector; the opening area of ​​the second blind hole specifically refers to the area of ​​the opening formed by the second blind hole on the surface of the current collector.

[0051] In some embodiments of this application, on the first surface or the second surface, the sum of the opening areas of the plurality of first blind holes and the plurality of second blind holes is 15.0%-78.5% of the surface area of ​​the first surface or the surface area of ​​the second surface. Specifically, if a plurality of blind holes are arranged on opposite sides of the current collector, the blind holes on the first surface or the second surface satisfy the above condition; further, the blind holes on both the first surface and the second surface satisfy the above condition. In this way, the number of first blind holes and second blind holes is controlled within a suitable range, reducing the interfacial impedance of the current collector, improving the bonding force between the current collector and the electrode material layer, while also taking into account the mechanical properties of the current collector. Specifically, based on the surface area of ​​the first surface or the surface area of ​​the second surface of the current collector, the sum of the opening areas of the plurality of first blind holes and the plurality of second blind holes can be 15.0%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55%, 60%, 65%, 70%, 75%, 78.5%, etc. In this embodiment of the application, the 1000*700 μm (700000 μm) single-sided surface of the current collector was observed using an optical microscope or SEM. 2 Within the area, the sum of the opening areas of the first blind hole and multiple second blind holes is 15.0%-78.5%.

[0052] For some embodiments of this application, please refer to Figure 1CThe first surface or the second surface has multiple first blind hole groups. Each first blind hole group includes one first blind hole and two second blind holes adjacent to the first blind hole. The line connecting the center of the first blind hole in the first blind hole group and the center of the two second blind holes forms a first triangle. If multiple blind holes are arranged on opposite sides of the current collector, the blind holes on the first surface or the second surface satisfy the above conditions. Furthermore, the blind holes on both the first surface and the second surface satisfy the above conditions. This arrangement is more conducive to the uniform coating of electrode paste on the surface of the current collector. Each first blind hole group includes a first blind hole that enhances the adhesion between the current collector and the electrode material layer, and a second blind hole that accelerates electron conduction. Two second blind holes surround one first blind hole, thereby fully homogenizing the electron conduction and ion conduction performance within the area of ​​the first blind hole group.

[0053] In some embodiments of this application, the angles of the three angles in the first triangle are in the range of 15°-120°, wherein the angle located at the first blind hole is in the range of 15°-120°, and the angle located at the second blind hole is in the range of 15°-85°. Specifically, the angle located at the first blind hole can be 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, 90°, 95°, 100°, 105°, 110°, 115°, 120°, etc. The angle located at the second blind hole can be, but is not limited to, 15°, 20°, 25°, 30°, 35°, 40°, 45°, 50°, 55°, 60°, 65°, 70°, 75°, 80°, 85°, etc. By controlling the angles of the first triangle within the aforementioned range, the relative distribution of blind holes in the first blind hole group is controlled. The appropriate relative distribution allows the radiation distance of the first and second blind holes to cover the entire first region, and the radiation regions of the two second blind holes overlap, thus facilitating the effect of the blind hole.

[0054] In some embodiments of this application, the first triangle is an isosceles triangle. This facilitates the preparation of the current collector and improves its uniformity. In this case, the base angles of the first triangle are all greater than or equal to 15° and less than or equal to 85°, and the vertex angle of the first triangle is greater than or equal to 15° and less than or equal to 120°. For example, the two base angles of the first triangle can simultaneously be 82.5°, 80°, 70°, 60°, 50°, 40°, 35°, 30°, 25°, 20°, etc. Further, when the first triangle is an isosceles triangle, the included angle between the lines connecting the centers of the first blind hole and the two second blind holes is the vertex angle of the first triangle. In some specific embodiments, the included angle between the lines connecting the centers of the first blind hole and the two second blind holes (…) Figure 1C α3) is 120°, and the other two angles ( Figure 1C In the equation, α1 and α2 are both 30°.

[0055] In some specific embodiments, multiple blind holes are arranged in an array on the first and / or second surfaces of the current collector. On two adjacent horizontal rows, any first blind hole and its two adjacent second blind holes constitute a first blind hole group. Further, the horizontal rows formed by first blind holes and the horizontal rows formed by second blind holes are arranged alternately, with any first blind hole and its two adjacent second blind holes on another adjacent horizontal row forming a first blind hole group. If multiple blind holes are arranged on opposite sides of the current collector, the blind holes on the first or second surface satisfy the above conditions; further, the blind holes on both the first and second surfaces satisfy the above conditions. It is understood that adjacent first blind hole groups may share one or two second blind holes. In this case, in some specific embodiments, the ratio of the number of first blind holes to the number of second blind holes on the first or second surface of the current collector is 1:2.

[0056] In some embodiments of this application, in each first blind hole group, the opening area ratio of the first blind hole is in the range of 2.0%-44.6%, and the opening area ratio of the second blind hole is in the range of 1.1%-8.9%. In the embodiments of this application, the opening area ratio of the first blind hole (second blind hole) refers to the percentage of the area of ​​the portion of the first blind hole (second blind hole) located within the first blind hole group to the total area of ​​the first triangle. Specifically, the opening area ratio of the first blind hole can be 2.0%, 5.0%, 10.0%, 15.0%, 20.0%, 25.0%, 30.0%, 35.0%, 40.0%, 42.0%, 43.0%, 44.0%, 44.5%, 44.6%, etc. The opening area percentage of the second blind via can be 1.1%, 1.5%, 2.0%, 2.5%, 3.0%, 3.5%, 4.0%, 4.5%, 5.0%, 5.5%, 6.0%, 6.5%, 7.0%, 7.5%, 8.0%, 8.5%, 8.8%, etc. Setting the area percentages of the first and second blind vias within the first blind via group within these ranges effectively limits the distance between the edges of the first and second blind vias in the first blind via group. This allows for a more rational distribution of multiple first and second blind vias, fully leveraging their synergistic effect. Specifically, it significantly reduces the interfacial impedance of the current collector within the first blind via group and enhances the adhesion between the current collector and the electrode material layer, thereby improving the overall performance of the current collector and minimizing the risk of excessively dense blind via arrangement affecting the mechanical properties of the current collector. Furthermore, in multiple first blind via groups, the opening area percentages of the first and second blind vias are equal.

[0057] In some specific embodiments, the side lengths of the first triangle are each independently within the range of 100μm-500μm, satisfying the condition that "the sum of any two sides of the triangle is greater than the third side, and the difference between any two sides is less than the third side." Specifically, the side lengths of the first triangle can be independently 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, etc.

[0058] In other embodiments of this application, please refer to Figures 2-3The first surface or the second surface has multiple groups of second blind holes. Each group of second blind holes includes three adjacent second blind holes and the first blind hole. The line connecting the centers of the three second blind holes in the second group forms a second triangle, and the first blind hole in the second group is located in the second triangle. If multiple blind holes are arranged on opposite sides of the current collector, the blind holes on the first or second surface satisfy the above conditions. Furthermore, the blind holes on both the first and second surfaces satisfy the above conditions. This arrangement can also improve the uniformity of the current collector, allowing it to uniformly reduce the interfacial impedance at various points and uniformly improve the bonding strength between the current collector and the electrode material layer. In some specific embodiments, the second triangle is an isosceles triangle.

[0059] In some embodiments of this application, the side lengths of the second triangle are each independently within the range of 100μm-500μm. Specifically, the side lengths of the second triangle can be independently 100μm, 150μm, 200μm, 250μm, 300μm, 350μm, 400μm, 450μm, 500μm, etc., satisfying the condition that "the sum of any two sides of the triangle is greater than the third side, and the difference between any two sides is less than the third side." In this way, the current collector surface can have a suitable density of first and second blind holes, thereby improving the interfacial bonding performance and electronic conductivity of the current collector while also giving it better mechanical properties.

[0060] For some embodiments of this application, please refer to Figure 1B The thickness of the current collector is h, where 5μm ≤ h ≤ 20μm. For example, the thickness of the current collector can be, but is not limited to, 5μm, 8μm, 10μm, 12μm, 15μm, 18μm, 20μm, etc.

[0061] For some embodiments of this application, please refer to Figure 1B The depths of the first blind hole (h1) and the second blind hole (h2) are each independently 1.5%-50% of the current collector thickness (h). This allows the specific surface areas of the first and second blind holes to be controlled within suitable ranges, thereby improving the interfacial bonding performance of the current collector, reducing interfacial impedance, and ensuring good mechanical properties of the current collector. Specifically, the depths of the first blind hole (h1) and the second blind hole (h2) can each be independently 2.0%, 5.0%, 7.5%, 10.0%, 12.5%, 15.0%, 17.5%, 20.0%, 22.5%, 25.0%, 27.5%, 30.0%, 32.5%, 35.0%, 37.5%, 40.0%, 42.5%, 45.0%, 47.5%, and 50.0% of the current collector thickness (h).

[0062] In this embodiment, on one side surface of the current collector, the depths (h1) of the plurality of first blind holes can be equal or unequal; the depths (h2) of the plurality of second blind holes can be equal or unequal; the depths of the first blind holes and the second blind holes can be equal or unequal, depending on the actual application. Similarly, when multiple blind holes are arranged on both opposite sides of the current collector, the depths of the first blind holes and the second blind holes on the first surface can be equal or unequal to the depths of the first blind holes and the second blind holes on the second surface.

[0063] In some specific embodiments of this application, when the current collector thickness h is 8 μm, the depth of the first blind hole is h1 and the depth of the second blind hole is h2, where 0.2 μm ≤ h1 ≤ 4 μm and 0.2 μm ≤ h2 ≤ 4 μm. For example, when the current collector thickness h is 13 μm, the depths h1 of the first blind hole and h2 of the second blind hole can each be independently 0.2 μm, 0.5 μm, 0.8 μm, 1.0 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2.0 μm, 2.2 μm, 2.5 μm, 2.8 μm, 3.0 μm, 3.2 μm, 3.5 μm, 3.8 μm, 4.0 μm, etc.

[0064] In other specific embodiments, when the current collector thickness h is 13 μm, 0.2 μm ≤ h1 ≤ 6.5 μm, and 0.2 μm ≤ h2 ≤ 6.5 μm. For example, when the current collector thickness h is 13 μm, the depth h1 of the first blind hole and the depth h2 of the second blind hole can each independently be 0.2 μm, 0.5 μm, 0.8 μm, 1.0 μm, 1.2 μm, 1.5 μm, 1.8 μm, 2.0 μm, 2.2 μm, 2.5 μm, 2.8 μm, 3.0 μm, 3.2 μm, 3.5 μm, 3.8 μm, 4.0 μm, 4.2 μm, 4.5 μm, 4.8 μm, 5.0 μm, 5.2 μm, 5.5 μm, 5.8 μm, 6.0 μm, 6.2 μm, 6.5 μm, etc.

[0065] In this embodiment, the distance between the edge of the current collector and the edge of the outermost blind hole is d, where 0.01mm ≤ d ≤ 5mm. That is, leaving a certain distance at the edge of the current collector without blind holes effectively avoids the generation of burrs and streaks in the current collector, improving the stability and safety performance of the battery. For example, the distance d between the edge of the current collector and the edge of the outermost blind hole can be 0.01mm, 0.05mm, 0.10mm, 0.50mm, 1.00mm, 1.50mm, 2.00mm, 2.50mm, 3.00mm, 3.50mm, 4.00mm, 4.50mm, 5.00mm, etc.

[0066] In some embodiments of this application, the aforementioned method for preparing the current collector includes: providing a foil material and processing it using a mechanical molding method to obtain the current collector provided in the embodiments of this application. In some specific embodiments, the mechanical molding is performed by molding the foil material with rollers having raised surfaces to form blind holes on the foil surface. The above preparation method has high process reliability, simple steps, high production efficiency, and high product yield.

[0067] More importantly, during the molding process described above, the original foil material at the blind hole location is squeezed and accumulated to the hole wall, making the material density of the current collector at and near the blind hole wall higher than other locations (locations without blind holes and with a certain distance from the blind hole wall). When electrode material is coated on the surface of the current collector and the electrode sheet is rolled, the higher material density of the current collector at the blind hole wall provides a buffering effect against the rolling force, reducing the elongation deformation of the blind hole wall under the rolling force. This further reduces the risk of the electrode material in the blind hole detaching from it, ensuring higher adhesion strength of the electrode material in the blind hole, thereby improving the peel strength of the final electrode sheet and reducing the probability of electrode sheet detachment. In existing technologies, when preparing current collectors with through holes, the foil material at the target through hole is directly punched off, meaning the density of the through hole wall material does not change. During the electrode sheet rolling process, there is no buffering effect when the through hole is subjected to the rolling force, resulting in greater elongation and deformation at the through hole wall. This increases the risk of the electrode material inside the through hole detaching from the through hole, making the resulting electrode sheet more prone to material loss.

[0068] Accordingly, this application also provides an electrode sheet, including the current collector provided in this application embodiment. Due to the use of the current collector provided in this application embodiment, the electrode sheet has high peel strength and good structural stability during battery cycling, which is beneficial for improving the battery's cycle performance; simultaneously, the electrode sheet also has high electronic conductivity and ionic conductivity, which can improve the final battery's rate performance.

[0069] The electrode sheet exhibits high peel strength, which can be understood as follows: when the current collector thickness and electrode material layer thickness of the electrode sheet are equal, the peel strength of the electrode sheet provided in this application embodiment is greater than that of the electrode sheet using foil of the same thickness as the current collector. Alternatively, when the peel strength of the electrode sheet provided in this application embodiment is equal to that of the electrode sheet using foil of the same thickness as the current collector, the electrode material layer thickness of the electrode sheet in this application embodiment is greater. Specifically, when the peel force of the positive electrode sheet is 15N, the positive electrode sheet using foil as the current collector can have a maximum positive electrode material layer thickness of 123μm, but using the current collector provided in this application embodiment, the positive electrode material layer thickness can reach 126μm. Taking the negative electrode sheet as an example, when the peel force of the negative electrode sheet is 15N, the negative electrode sheet using foil as the current collector can have a maximum negative electrode material layer thickness of 170μm, but using the current collector provided in this application embodiment, the negative electrode material layer thickness can reach 175μm.

[0070] The electrode plates provided in the embodiments of this application can be either positive or negative electrode plates.

[0071] Accordingly, this application also provides a battery, including the electrode plates provided in this application embodiment. Due to the use of the aforementioned electrode plates, the battery exhibits both good cycle performance and rate performance, and can achieve higher energy density.

[0072] In this embodiment of the application, the battery can be a liquid battery, a semi-solid battery, or an all-solid battery.

[0073] In some embodiments of this application, the battery includes a positive electrode, a negative electrode, a separator and an electrolyte disposed between the positive electrode and the negative electrode.

[0074] In other embodiments of this application, the battery includes a positive electrode, a negative electrode, and a solid electrolyte disposed between the positive and negative electrodes.

[0075] In the embodiments of this application, the battery may be a lithium-ion battery, a sodium-ion battery, a potassium-ion battery, a magnesium-ion battery, etc., but is not limited to these.

[0076] In this embodiment of the application, the battery may use the current collector provided in this embodiment in the positive electrode, or the current collector provided in this embodiment in the negative electrode, or both the positive and negative electrodes may use the current collector provided in this embodiment.

[0077] This application also provides an electrical device, including the battery provided in this application embodiment. The battery is used to power the electrical device. Because it incorporates the battery provided in this application embodiment, the electrical device has high market competitiveness.

[0078] In some embodiments of this application, the aforementioned electrical equipment includes, but is not limited to, 3C electronic products such as mobile phones, computers, laptops, and smartwatches, as well as powered vehicles. Powered vehicles include, but are not limited to, new energy vehicles and electric bicycles.

[0079] The technical solution of this application is further described below with reference to several embodiments.

[0080] Example 1

[0081] A current collector has a first surface with an array of multiple cylindrical first blind holes with a depth of 0.2 μm and multiple cylindrical second blind holes with a depth of 0.2 μm. The diameter of the first blind holes is 50 μm, and the diameter of the second blind holes is 10 μm. On the first surface of the current collector, the ratio of the number of first blind holes to the number of second blind holes is 1:8, and the sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 15.0% of the area of ​​the first surface of the current collector.

[0082] The second surface, opposite the first surface, also has multiple cylindrical first blind holes with a depth of 0.2 μm and multiple cylindrical second blind holes with a depth of 0.2 μm. The diameter of the first blind holes is 50 μm, and the diameter of the second blind holes is 10 μm. On the second surface of the current collector, the ratio of the number of first blind holes to the number of second blind holes is 1:8, and the sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 15.0% of the area of ​​the second surface of the current collector. Furthermore, the orthographic projections of the blind holes on the first surface and the blind holes on the second surface do not overlap.

[0083] Example 2

[0084] The only difference from Example 1 is that the sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 78.5% of the first surface area of ​​the current collector.

[0085] The second surface array has multiple cylindrical first blind holes and multiple cylindrical second blind holes, each with a depth of 0.1 μm. The diameter of the first blind holes is 40 μm, and the diameter of the second blind holes is 15 μm. On the second surface of the current collector, the ratio of the number of first blind holes to the number of second blind holes is 1:4, and the sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 12.0% of the area of ​​the second surface of the current collector. Furthermore, the orthographic projections of the blind holes on the first surface and the blind holes on the second surface do not overlap.

[0086] Example 3

[0087] The only difference from Example 1 is that on the first surface of the current collector, the ratio of the number of first blind holes to the number of second blind holes is 1:8, and the sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 47.0% of the area of ​​the first surface of the current collector.

[0088] The second surface also has multiple cylindrical first blind holes with a depth of 0.3 μm and multiple cylindrical second blind holes with a depth of 0.1 μm. The diameter of the first blind holes is 55 μm, and the diameter of the second blind holes is 20 μm. On the second surface of the current collector, the ratio of the number of first blind holes to the number of second blind holes is 1:2, and the sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 14.0% of the area of ​​the second surface of the current collector. Furthermore, the orthographic projections of the blind holes on the first surface and the blind holes on the second surface do not overlap.

[0089] Example 4

[0090] The only difference from Example 1 is that on the first surface of the current collector, the ratio of the number of first blind holes to the number of second blind holes is 1:4, and the sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 15.0% of the area of ​​the first surface of the current collector.

[0091] The second surface also has multiple cylindrical first blind holes with a depth of 0.2 μm and multiple cylindrical second blind holes with a depth of 0.2 μm. The diameter of the first blind holes is 60 μm, and the diameter of the second blind holes is 10 μm. On the second surface of the current collector, the ratio of the number of first blind holes to the number of second blind holes is 1:4, and the sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 18.0% of the area of ​​the second surface of the current collector. Furthermore, the orthographic projections of the blind holes on the first surface and the blind holes on the second surface do not overlap.

[0092] Example 5

[0093] The only difference from Example 1 is that on the first surface of the current collector, the ratio of the number of first blind holes to the number of second blind holes is 1:10, and the sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 15.0% of the area of ​​the first surface of the current collector.

[0094] The second surface also has multiple cylindrical first blind holes with a depth of 0.2 μm and multiple cylindrical second blind holes with a depth of 0.2 μm. The diameter of the first blind holes is 60 μm, and the diameter of the second blind holes is 10 μm. On the second surface of the current collector, the ratio of the number of first blind holes to the number of second blind holes is 1:2, and the sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 18.0% of the area of ​​the second surface of the current collector. Furthermore, the orthographic projections of the blind holes on the first surface and the blind holes on the second surface do not overlap.

[0095] Example 6

[0096] The only difference from Example 1 is that the diameter of the first blind hole is 100 μm and the diameter of the second blind hole is 30 μm.

[0097] The second surface also has multiple cylindrical first blind holes with a depth of 0.2 μm and multiple cylindrical second blind holes with a depth of 0.2 μm. The diameter of the first blind holes is 100 μm, and the diameter of the second blind holes is 30 μm. On the second surface of the current collector, the ratio of the number of first blind holes to the number of second blind holes is 1:8, and the sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 16.0% of the area of ​​the second surface of the current collector. Furthermore, the orthographic projections of the blind holes on the first surface and the blind holes on the second surface do not overlap.

[0098] Example 7

[0099] The only difference from Example 1 is that the diameter of the first blind hole is 50 μm and the diameter of the second blind hole is 30 μm.

[0100] The second surface also has multiple cylindrical first blind holes with a depth of 0.2 μm and multiple cylindrical second blind holes with a depth of 0.2 μm. The diameter of the first blind holes is 100 μm, and the diameter of the second blind holes is 30 μm. On the second surface of the current collector, the ratio of the number of first blind holes to the number of second blind holes is 1:4, and the sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 26.0% of the area of ​​the second surface of the current collector. Furthermore, the orthographic projections of the blind holes on the first surface and the blind holes on the second surface do not overlap.

[0101] Example 8

[0102] The only difference from the embodiment is that on the first surface of the current collector, the ratio of the number of first blind holes to the number of second blind holes is 1:2. Horizontal rows composed of first blind holes and horizontal rows composed of second blind holes are arranged alternately to form multiple groups of first blind holes. The first triangle is an isosceles triangle with angles of 120°, 30°, and 30°. In each group of first blind holes, the opening area of ​​the first blind holes accounts for 5.6%, and the opening area of ​​the second blind holes accounts for 2.1%.

[0103] On the second surface, the ratio of the number of first blind holes to the number of second blind holes is 1:4. Horizontal rows composed of first blind holes and horizontal rows composed of second blind holes are arranged alternately, forming multiple groups of first blind holes. The first triangle is an isosceles triangle with angles of 120°, 30°, and 30°. In each group of first blind holes, the opening area of ​​the first blind holes accounts for 6%, and the opening area of ​​the second blind holes accounts for 12.4%. Furthermore, the orthographic projections of the blind holes on the first surface and the blind holes on the second surface do not overlap.

[0104] Example 9

[0105] The only difference from Embodiment 1 is that, on the first surface of the current collector, horizontal rows composed of first blind holes and horizontal rows composed of second blind holes are arranged alternately, and any three adjacent second blind holes form a second triangle, forming multiple groups of second blind holes, and the second triangle is an isosceles triangle. The sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 25% of the area of ​​the first surface of the current collector.

[0106] On the second surface of the current collector, horizontal rows of first blind holes and horizontal rows of second blind holes are arranged alternately. Any three adjacent second blind holes form a second triangle, forming multiple groups of second blind holes, and the second triangles are isosceles triangles. The sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 15% of the area of ​​the first surface of the current collector. Furthermore, the orthographic projections of the blind holes on the first surface and the blind holes on the second surface do not overlap.

[0107] Example 10

[0108] The difference from Embodiment 1 is that multiple blind holes are arranged only on the first surface of the current collector. That is, multiple cylindrical first blind holes with a depth of 0.2 μm and multiple cylindrical second blind holes with a depth of 0.2 μm are arranged in an array on the first surface of the current collector. The diameter of the first blind holes is 50 μm and the diameter of the second blind holes is 10 μm. The ratio of the number of first blind holes to the number of second blind holes is 1:8, and the sum of the opening areas of the multiple first blind holes and the multiple second blind holes is 15.0% of the area of ​​the first surface of the current collector.

[0109] To highlight the beneficial effects of the embodiments of this application, the following comparative examples are provided.

[0110] Comparative Example 1

[0111] An 8μm thick aluminum foil was used directly as the current collector.

[0112] Comparative Example 2

[0113] A current collector has multiple cylindrical blind holes, each 0.2 μm deep and 50 μm in diameter, arranged in an array on one side surface. The opening area of ​​these blind holes accounts for 15.0% of the area of ​​one side surface of the current collector. A second surface array also has multiple cylindrical blind holes, each 0.2 μm deep and 50 μm in diameter, arranged in an array. The opening area of ​​these blind holes also accounts for 15.0% of the area of ​​one side surface of the current collector. Furthermore, the orthographic projections of the blind holes on the first surface and the second surface do not overlap.

[0114] Comparative Example 3

[0115] The difference from Example 1 is that the diameter of the first blind hole is 120 μm and the diameter of the second blind hole is 45 μm; on the second surface of the current collector, the diameter of the first blind hole is 120 μm and the diameter of the second blind hole is 45 μm. Furthermore, the orthographic projections of the blind holes on the first surface and the blind holes on the second surface do not overlap.

[0116] Comparative Example 4

[0117] The difference from Example 1 is that the diameter of the first blind hole is 35 μm and the diameter of the second blind hole is 5 μm; on the second surface of the current collector, the diameter of the first blind hole is 35 μm and the diameter of the second blind hole is 5 μm. Furthermore, the orthographic projections of the blind holes on the first surface and the blind holes on the second surface do not overlap.

[0118] Performance testing

[0119] (1) Preparation of the test battery:

[0120] Preparation of the positive electrode: The positive electrode active material (specifically Na) is prepared in a mass ratio of 95:3:2. 0.97 Ni 0.34 Fe 0.31 Mn 0.35 O2, a conductive agent (specifically carbon black), and a binder (specifically polyvinylidene fluoride) are dispersed in a solvent (specifically N-methylpyrrolidone) to obtain a positive electrode slurry. The positive electrode slurry is coated onto the surface of a positive electrode current collector (aluminum foil), and after drying, rolling, and slitting, a positive electrode sheet is obtained.

[0121] Preparation of the negative electrode sheet: A negative electrode active material (specifically hard carbon), a conductive agent (specifically carbon black), and a binder (specifically aqueous carboxymethyl cellulose) in a mass ratio of 95:3:2 are dispersed in a solvent (specifically water) to obtain a negative electrode slurry. The negative electrode slurry is coated on the surface of the current collector provided in each embodiment and comparative example, and after drying, rolling, and slitting, a negative electrode sheet is obtained. The thickness of each negative electrode sheet is guaranteed to be 177 μm, of which the thickness of the negative electrode active material layer is 164 μm. The thickness of the negative electrode sheet is measured using a film thickness gauge at a depth of 5 mm inward from the edge of the negative electrode sheet.

[0122] Battery fabrication: Positive and negative electrode sheets and a separator are stacked, with the separator positioned between the positive and negative electrode sheets. The layers are then wound and injected with electrolyte. After formation and degassing processes, the battery to be tested is obtained. The electrolyte contains an electrolyte salt (specifically NaClO4) concentration of 1 mol / L, and the solvent is a 1:1 volume ratio mixture of ethylene carbonate (EC) and diethyl carbonate (DEC), with the solvent also containing 5 wt.% fluoroethylene carbonate.

[0123] (2) Peel strength test of negative electrode sheets of each embodiment and comparative example: First, attach a strip of double-sided tape to the center of a steel plate (300mm long, 40mm wide). Peel off the double-sided tape and attach the negative electrode sheets of each embodiment and comparative example (100mm long, 10mm wide), which are smaller than the size of the steel plate, to the tape. Then, place the steel plate with the fixed electrode sheet attached at 180° on the clamp of the universal tensile testing machine. After zeroing, set the test width, electrode peel length of 100mm, peel speed of 50mm / min, and start the test to obtain the peel strength curve and average value. The peel strength test results of the negative electrode sheets of each embodiment and comparative example are summarized in Table 1.

[0124] (3) Loop testing:

[0125] At 25°C, the batteries prepared in the examples and comparative examples were charged to 3.9V at a 1C rate, and then discharged to 1.5V at a 1C rate. Using the capacity of the first cycle as the initial capacity, the capacity retention rate after 100 cycles was calculated using the formula: Capacity retention rate after the nth cycle = (Discharge capacity after the nth cycle / Discharge capacity of the first cycle) * 100%. The discharge capacity of the 100th cycle divided by the initial capacity yields the corresponding capacity retention rate. The results are summarized in Table 1.

[0126] (4) Rate performance test: At 25°C, the batteries prepared in the examples and comparative examples were charged to 3.9V at a rate of 0.2C, and then discharged to 1.5V at rates of 0.2C, 0.5C, 1C, 2C and 3C respectively. The discharge capacity of the first cycle at 0.2C was used as the initial capacity, and the rate performance was calculated. The calculation formula is: Discharge capacity retention rate at 3C rate = (Discharge capacity at 3C / Discharge capacity at 0.2C) * 100%.

[0127] (5) Energy density test: Under room temperature (25℃±2℃) conditions, test according to the following steps: 1) Discharge current of 1C to 1.5V and let stand for 1 hour; 2) Charge current of 1C to 3.9V and let stand for 1 hour; 3) Repeat 3 times and measure the discharge energy E (in Wh). The weight energy density of the battery = battery capacity × average discharge plateau / weight.

[0128] Table 1

[0129]

[0130] As can be seen from the data in Table 1, when the thickness of the negative electrode active material layer is the same, compared with the comparative example, the negative electrode sheet obtained by the current collector system provided in this application has a higher peel strength, and the final battery has better cycle performance and rate performance, as well as higher energy density.

[0131] The above description is an exemplary embodiment of this application. It should be noted that those skilled in the art can make several improvements and modifications without departing from the principles of this application, and these improvements and modifications are also considered to be within the scope of protection of this application.

Claims

1. A current collector, characterized in that, The current collector is provided with a plurality of blind holes. The current collector has a first surface and a second surface arranged oppositely, and the plurality of blind holes are distributed on the first surface and / or the second surface; The blind holes on the first surface or the second surface include first blind holes and second blind holes. Among them, the aperture of the first blind hole is D1, 50μm < D1 ≤ 100μm; the aperture of the second blind hole is D2, 10μm < D2 ≤ 30μm.

2. The current collector according to claim 1, characterized in that, The plurality of blind holes are distributed on the first surface and the second surface, and along the thickness direction of the current collector, the orthographic projections of at least some of the blind holes on the first surface do not overlap with the orthographic projections of the blind holes on the second surface.

3. The current collector according to claim 2, characterized in that, Based on the sum of the opening areas of the plurality of blind holes on the first surface, the sum of the area ratios of the blind holes on the first surface that do not overlap with the orthographic projections of the blind holes on the second surface is ≥ 30%.

4. The current collector according to claim 1 or 2, characterized in that, On the first surface or the second surface, each of the first blind holes is surrounded by a plurality of the second blind holes; the ratio of the number of the first blind holes to the number of the second blind holes is within the range of 1:(2 - 8).

5. The current collector according to claim 1 or 2, characterized in that, On the first surface or the second surface, there are a plurality of first blind hole groups. Each first blind hole group includes one first blind hole and two second blind holes adjacent to the first blind hole, and the connection line between the centers of the first blind hole and the two second blind holes in the first blind hole group forms a first triangle; In the first triangle, the angles of the three corners are within the range of 15° - 120°. Among them, the angle value at the position of the first blind hole is 15° - 120°, and the angle value at the position of the second blind hole is 15 - 85°.

6. The current collector according to claim 5, characterized in that, The first triangle is an isosceles triangle.

7. The current collector according to claim 5, characterized in that, In each first blind hole group, the area ratio of the opening of the first blind hole is within the range of 2.0% - 44.6%, and the area ratio of the opening of the second blind hole is within the range of 1.1% - 8.9%.

8. The current collector according to claim 1 or 2, characterized in that, On the first surface or the second surface, there are a plurality of second blind hole groups. Each second blind hole group includes three adjacent second blind holes and the first blind hole, and the connection line between the centers of the three second blind holes in the second blind hole group forms a second triangle. The first blind hole in the second blind hole group is located in the second triangle; The second triangle is an isosceles triangle.

9. The current collector according to claim 8, characterized in that, The side lengths of the second triangle are each independently within the range of 100μm - 500μm.

10. The current collector according to claim 1 or 2, characterized in that, On the first surface or the second surface, the sum of the area ratios of the openings of the plurality of first blind holes and the plurality of second blind holes is 15.0% - 78.5% of the surface area of the first surface or the second surface.

11. The current collector according to claim 1 or 2, characterized in that, The depths of the first blind hole and the second blind hole are each independently 1.5% - 50% of the thickness of the current collector.

12. The current collector according to claim 1 or 2, characterized in that, The ratio of the opening area of each second blind hole to the opening area of each first blind hole is 1:(0.01 - 0.6).

13. An electrode sheet, characterized in that, The electrode pole piece includes the current collector according to any one of claims 1 - 12.

14. A battery, characterized in that, The battery includes the electrode pole piece according to claim 13.

15. An electrical appliance, characterized in that, The electrical device includes the battery as described in claim 14.

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