Current collector, electrode sheet, battery, and electric device

Abstract

A current collector (100), an electrode sheet, a battery, and an electric device. A plurality of blind vias (30) are formed in the current collector (100), the current collector (100) has a first surface (10) and a second surface (20) arranged oppositely, and the plurality of blind vias (30) are distributed in the first surface (10) and / or the second surface (20). The blind vias (30) in the first surface (10) or the second surface (20) comprise first blind vias (31) and second blind vias (32). The diameter of each first blind via (31) is D1, and D1 is greater than or equal to 50 μm and less than or equal to 100 μm; the diameter of each second blind via (32) is D2, and D2 is greater than or equal to 10 μm and less than or equal to 30 μm.

Description

Current collectors, electrodes, batteries and electrical equipment

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on September 8, 2023, with application number 2023111571759 and application name “Current Collector, Electrode Plate, Battery and Electrical Equipment”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to the field of battery technology, and in particular to current collectors, electrode plates, batteries and electrical equipment. Background Art

[0003] As one of the key components of secondary batteries, the current collector is used to carry the electrode material layer and collect and output the current generated by the active substances in the electrode material, while also inputting the electrode current into the electrode material layer. An ideal current collector needs to have high electronic conductivity, excellent mechanical properties, and strong adhesion to the electrode material layer. However, in actual applications, manufacturers often use foil materials (such as aluminum foil, copper foil, etc.) directly as current collectors. The bonding strength between this type of current collector and the electrode material layer is low, and the interface contact resistance is high, which affects the performance of the battery.

[0004] In order to solve the above problems, porous current collectors came into being. However, existing porous current collectors are generally obtained by making through holes on foil, which has low mechanical strength and limited effect on improving the bonding strength between the current collector and the electrode material layer and the interface contact resistance of the current collector.

[0005] Summary of the Invention

[0006] In view of this, the present invention provides a current collector, an electrode plate, a battery, and an electrical device. The current collector has a novel structure that provides both strong adhesion to the electrode material layer and high electronic conductivity, thereby improving the battery's cycle performance and rate capability.

[0007] In a first aspect, the present application provides a current collector, wherein a plurality of blind holes are provided on the current collector, the current collector has a first surface and a second surface opposite to each other, and the plurality of blind holes are distributed on the first surface and / or the second surface;

[0008] The blind holes on the first surface or the second surface include a first blind hole and a second blind hole; wherein the aperture of the first blind hole is D1, 50 μm≤D1≤100 μm; and the aperture of the second blind hole is D2, 10 μm≤D2≤30 μm.

[0009] The current collector surface is arranged with multiple blind holes, which can improve the adhesion between the current collector and the electrode material layer and accelerate electron conduction between the two layers. More importantly, a single surface of the current collector is dispersed with first blind holes with a larger pore size and second blind holes with a relatively smaller pore size. The first blind holes have a pore size of 50μm-100μm, which can be filled with more electrode material and further improve the adhesion between the current collector and the electrode material layer. The second blind holes have a relatively smaller pore size and a larger specific surface area than the first blind holes, which increases the contact area between the electrode material and the current collector, thereby better accelerating electron conduction and reducing the interfacial impedance of the current collector. Therefore, the synergistic effect of the first and second blind holes on a single surface of the current collector can be used to provide an electrode plate with both high peel strength and high electronic conductivity, thereby providing a battery with good cycling stability and excellent rate performance.

[0010] A second aspect of the present application provides an electrode plate, which includes the current collector provided in the first aspect of the present application.

[0011] Due to the use of the current collector provided in the embodiment of the present application, the electrode plate has a high peel strength and good structural stability during the battery cycle, which is beneficial to improving the battery cycle performance; at the same time, the electrode plate also has a high electronic conductivity and ionic conductivity, which can improve the rate performance of the final battery.

[0012] The third aspect of the present application provides a battery, comprising the electrode plate provided in the second aspect of the present application. Due to the use of the electrode plate, the battery has both good cycle performance and rate performance, and can achieve a higher energy density.

[0013] A fourth aspect of the present application provides an electrical device, comprising the battery provided in the third aspect of the present application. The battery is used to power the electrical device. Due to the inclusion of the battery provided in an embodiment of the present application, the electrical device has high market competitiveness. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] FIG1A is a partial top view of a current collector provided in one embodiment of the present application;

[0015] FIG1B is a cross-sectional view of a current collector provided in another embodiment of the present application;

[0016] FIG1C is a partial top view of a current collector having a plurality of first blind hole groups provided in one embodiment of the present application;

[0017] FIG2 is a partial top view of a current collector having a plurality of second blind hole groups provided by another embodiment of the present application;

[0018] FIG3 is a partial top view of a current collector having a plurality of second blind hole groups provided in yet another embodiment of the present application.

[0019] Description of the accompanying drawings: 100 - current collector; 10 - first surface; 20 - second surface; 30 - blind hole; 31 - first blind hole; 32 - second blind hole. DETAILED DESCRIPTION

[0020] As a key component of secondary batteries, the current collector's structural characteristics and electrochemical properties influence battery performance. The current collector performs various functions simultaneously, such as supporting the electrode material layer and collecting and transporting electrons. Improving the adhesion between the battery material layer and the current collector and reducing the current collector's interfacial resistance facilitates its application in the electrode sheet and improves the performance of the electrode sheet.

[0021] Referring to FIG. 1A to FIG. 1C , an embodiment of the present application provides a current collector 100 having a plurality of blind holes 30 disposed thereon. 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.

[0022] The blind holes 30 on the first surface 10 or the second surface 20 include a first blind hole 31 and a second blind hole 32 , wherein the aperture of the first blind hole 31 is D1, 50 μm≤D1≤100 μm; the aperture of the second blind hole 32 is D2, 10 μm≤D2≤30 μm.

[0023] In the embodiment of the present application, the current collector has a first surface 10 and a second surface 20 disposed opposite each other. In the embodiment of the present application, the first blind holes 31 and the second blind holes 32 may be distributed on the first surface 10 of the current collector, or may be distributed on the second surface 20 of the current collector. Alternatively, the first blind holes 31 and the second blind holes 32 may be distributed on both the first surface 10 and the second surface 20 of the current collector. When the first blind holes 31 and the second blind holes 32 are distributed on both the first surface 10 and the second surface 20 of the current collector 100, the number of the first blind holes 31 and the number of the second blind holes 32 on the first surface 10 and the second surface 20 may be the same or different; the apertures of the first blind holes 31 and the apertures of the second blind holes 32 may be the same or different; and the total number of the blind holes 30 may be the same or different.

[0024] In the embodiment of the present application, the blind hole specifically refers to a non-through hole.

[0025] It can be understood that the preparation process of the electrode plate generally includes: preparing electrode slurry (for example, positive electrode slurry, negative electrode slurry), coating the electrode slurry on the surface of the current collector, and the electrode slurry can be filled into the blind hole. After drying, this part of the slurry can serve 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 with the flat foil, under the same orthographic projection area, the direct contact area between the electrode slurry and the blind hole is larger, which can also help improve the adhesion between the electrode material layer and the current collector, thereby greatly improving the peel strength of the electrode plate. More importantly, the single-side surface of the current collector is simultaneously dispersed with a first blind hole with a larger pore size and a second blind hole with a relatively smaller pore size; the pore size of the first blind hole is 50μm-100μm, which can be filled with more electrode slurry. After curing, this part of the slurry can better play the role of "anchor", which is more conducive to improving the adhesion between the current collector and the electrode material layer; while the pore size of the second blind hole is smaller and the specific surface area is larger than that of the first blind hole. The contact area between the electrode material and the current collector is larger, which can better accelerate electron conduction and thus reduce the interfacial impedance of the current collector. Therefore, the single-side surface of the above-mentioned current collector has both the first blind hole and the second blind hole. Under the synergistic effect of the two, the current collector can be used to provide an electrode plate with both high peel strength and high electronic conductivity, thereby providing a battery with good cycle stability and excellent rate performance.

[0026] In addition, compared with the current collector with through holes commonly used in the prior art, when the thickness of the current collector is equal, the depth of the blind hole is significantly smaller than the through hole. When the electrode slurry coating speed is faster, the blind hole is more conducive to the filling of the electrode slurry (that is, the blind hole is easily filled with the electrode slurry), thereby improving the adhesion between the electrode material layer and the current collector, and improving the energy density of the battery. It can be seen that the use of the current collector provided in the embodiment of the present application can not only improve the peeling strength of the electrode plate and improve the energy density of the final battery, but also improve the production efficiency of the electrode plate while ensuring good battery performance. Furthermore, improving the adhesion between the current collector and the electrode material layer can also correspondingly improve the carrying capacity of the current collector on the electrode material layer. Therefore, the current collector provided in the embodiment of the present application, when the peeling strength of the electrode plates are equal, can carry a greater thickness of the electrode material layer than the prior art using the current collector provided in the embodiment of the present application.

[0027] It is also understandable that the ductility of the current collector material is better than that of the electrode slurry (electrode material layer). In the prior art, the current collector with through holes has the entire thickness of the current collector replaced by the less ductile electrode slurry (electrode material layer material) at the through hole position. However, the holes on the current collector of this application are blind holes. Therefore, after the electrode slurry is coated on its surface, any position of the resulting electrode sheet has a material with good ductility, thereby improving the extensibility of the electrode sheet and reducing the electrode sheet breakage rate.

[0028] In the embodiments of the present application, the apertures of the first blind hole and the second blind hole refer to the apertures of the openings of the first blind hole and the second blind hole on the surface of the current collector, respectively. In the embodiments of the present application, the maximum cross-sectional dimension of the blind hole can be constant, gradually decreasing, or gradually increasing, from the direction along the thickness direction of the blind hole opening toward the interior of the current collector. Taking the blind hole on the first surface as an example, the aperture of the blind hole can be uniform, gradually decreasing, or gradually increasing, from the direction along the thickness direction of the blind hole opening toward the second surface of the current collector.

[0029] In the embodiments of the present application, the opening shapes of the first blind hole and the second blind hole can each independently be circular, elliptical, square, rectangular, prismatic, polygonal, etc. When the first blind hole and the second blind hole are circular, their apertures 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 apertures refer to the diameters of the circumscribed circle of the polygon.

[0030] In the embodiment of the present application, the aperture D1 of the first blind via may be, but is not limited to, 50 μm, 52 μm, 55 μm, 58 μm, 60 μm, 62 μm, 65 μm, 68 μm, 70 μm, 72 μm, 75 μm, 78 μm, 80 μm, 82 μm, 85 μm, 88 μm, 90 μm, 92 μm, 95 μm, 98 μm, 100 μm, etc. If the aperture D1 of the first blind via is too small (less than 50 μm), 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 side wall of the blind hole will be weakened, and its anchoring effect will also be weakened, which is not conducive to the peeling strength of the electrode sheet; in addition, when the ratio of the opening area of ​​the blind hole to the surface area of ​​the collector remains unchanged, the aperture of the first blind hole is too large, and the total number of blind holes will be correspondingly too small, which is not conducive to the distribution of the blind holes on the surface of the collector, thereby affecting the uniformity of the final electrode sheet.

[0031] In the embodiment of the present application, the aperture D2 of the second blind hole can be, but is not limited to, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, 22 μm, 25 μm, 28 μm, 30 μm, etc. If the aperture D2 of the second blind hole is too small, it is not conducive to filling the electrode slurry, and thus the contact area between the material and the current collector cannot be fully increased. If the aperture D2 of the second blind hole is too large, the specific surface area of ​​the second blind hole is reduced, which is also not conducive to fully increasing the contact area between the material and the current collector. Therefore, whether the aperture D2 of the second blind hole is too large or too small, it is not conducive to reducing the interface impedance of the current collector.

[0032] In the embodiment of the present 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).

[0033] In some embodiments of the present application, first and second blind holes are distributed on the first and second surfaces of the current collector. That is, a plurality of the aforementioned first and second blind holes are arranged on the first and second surfaces of the current collector, respectively. This can simultaneously reduce the interfacial impedance of the current collector on both opposing surfaces and improve the adhesion between the current collector and the electrode material layer, thereby further improving the peel strength of the final electrode sheet and the cycle and rate performance of the final battery. In some specific embodiments, 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 multiple blind holes on the second surface. The blind holes are recessed into the current collector relative to the first and second surfaces of the current collector. Therefore, the current collector body thickness is relatively thin in the areas containing the blind holes. By ensuring 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 current collector can be prevented from having a thin thickness over a large area. This ensures better mechanical properties of the current collector, facilitates the preparation of the electrode sheet, and helps ensure the structural stability of the final electrode sheet, thereby enhancing the performance of the final battery.

[0034] In some embodiments, the sum of the opening area ratios of the blind holes on the first surface and / or the second surface is relatively small, so that the orthographic projections of the multiple blind holes on the first surface and the orthographic projections of the multiple blind holes on the second surface do not overlap in the thickness direction of the current collector. In this way, the mechanical properties of the current collector are relatively better. In other embodiments, the sum of the opening area ratios of the blind holes on the first surface and / or the second surface is relatively large. Along the thickness direction of the current collector, 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. In this case, based on the sum of the opening areas of the multiple blind holes on the first surface, along the thickness direction of the current collector, 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%. In this way, while maximizing the bonding strength between the current collector and the electrode material layer and reducing the interfacial impedance of the current collector, the mechanical properties of the current collector can also be taken into account, so that the current collector can fully bear the stress during the battery cycle and ensure the good structural stability of the electrode sheet during the battery cycle. Illustratively, based on the sum of the opening areas of the multiple blind holes on the first surface, the sum of the area proportions 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.

[0035] In the embodiments of the present application, 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 overlap includes but is not limited to the following situations: (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 the above situations are conducive to ensuring good mechanical properties of the current collector.

[0036] In some embodiments of the present application, a plurality of second blind holes are provided around each first blind hole on the first surface or the second surface. That is, if the current collector has a plurality of blind holes arranged only on the first surface, the plurality of blind holes on the first surface meet the above conditions. If a plurality of blind holes are arranged on the two opposite surfaces of the current collector, the blind holes on the first surface or the second surface meet the above conditions. Furthermore, the blind holes on both the first surface and the second surface meet 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. Such an arrangement is conducive to achieving the coordination effect of the first blind holes and the second blind holes at different positions on the single-side surface of the current collector, which can improve the uniformity of the current collector, so that the peeling strength and electronic conductivity of different positions of the final electrode sheet are higher.

[0037] In some embodiments of the present 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 a plurality of first blind holes and second blind holes are arranged on the two opposite surfaces of the current collector, the blind holes on the first surface or the second surface meet the above conditions, and further, the blind holes on the first surface and the second surface both meet the above conditions. The first blind holes and the second blind holes have a suitable number ratio, which is beneficial to balancing the interface impedance of the current collector and its adhesion to the electrode material layer, and is also beneficial to uniformizing the conductivity of ions in the current collector, so that the overall performance of the current collector is better, and further beneficial to 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 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.

[0038] In some embodiments of the present 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). For example, 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), that is, (2-4). This is more conducive to improving the bonding force between the current collector and the electrode material layer.

[0039] In the embodiment of the present 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.

[0040] In some embodiments of the present application, the sum of the opening areas of the plurality of first blind holes and the plurality of second blind holes on the first surface or the second surface is 15.0% to 78.5% of the surface area of ​​the first surface or 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 meet the above conditions. Furthermore, the blind holes on both the first surface and the second surface meet the above conditions. In this way, the number of first blind holes and second blind holes is controlled within an appropriate range, which can reduce the interfacial impedance of the current collector, improve the bonding strength between the current collector and the electrode material layer, and take into account the mechanical properties of the current collector. Specifically, based on the surface area of ​​the first surface or 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 the embodiment of the present application, the surface of the current collector on one side was observed by optical microscope or SEM with an area of ​​1000*700 μm (700000 μm 2 ), the sum of the opening areas of the first blind hole and the plurality of second blind holes accounts for 15.0%-78.5%.

[0041] In some embodiments of the present application, referring to FIG1C , there are multiple first blind hole groups on the first surface or the second surface, each of the first blind hole groups includes 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. If multiple blind holes are arranged on the two opposite sides of the current collector, the blind holes on the first surface or the second surface meet the above conditions, and further, the blind holes on the first surface and the second surface both meet the above conditions. Such an arrangement is more conducive to uniform coating of the electrode slurry on the surface of the current collector. Each first blind hole group includes a first blind hole that is conducive to enhancing the adhesion between the current collector and the electrode material layer, and a second blind hole that can accelerate electron conduction. The two second blind holes are arranged around one first blind hole, so that the electron conduction performance and ion conduction performance within the first blind hole group area can be fully uniformized.

[0042] In some embodiments of the present application, in the first triangle, the angles of the three corners are in the range of 15°-120°, wherein the angle of the corner located at the first blind hole is 15°-120°, and the angle of the corner located at the second blind hole is 15-85°. Specifically, the angle of the corner 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 of the corner 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 above range, the relative distribution positions of the blind holes in the first blind hole group are controlled. Suitable relative distribution positions enable the radiation distances of the first blind hole and the second blind hole to cover the entire first area, and the radiation areas of the two second blind holes overlap, thereby facilitating the blind hole effect.

[0043] In some embodiments of the present application, the first triangle is an isosceles triangle. This is more conducive to the preparation of the current collector and is also more conducive to improving the uniformity of the current collector. At this time, the base angles of the first triangle are 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 be 82.5°, 80°, 70°, 60°, 50°, 40°, 35°, 30°, 25°, 20°, etc. at the same time. Furthermore, when the first triangle is an isosceles triangle, the angle between the first blind hole and the line connecting the centers of the two second blind holes is the vertex angle of the first triangle. In some specific embodiments, the angle between the first blind hole and the line connecting the centers of the two second blind holes (α3 in Figure 1C) is 120°, and the other two angles (α1 and α2 in Figure 1C) are both 30°.

[0044] In some specific embodiments, on the first surface and / or the second surface of the current collector, a plurality of blind holes are arranged in an array. On two adjacent horizontal rows, any first blind hole and the two second blind holes adjacent thereto constitute a first blind hole group. Furthermore, the horizontal rows composed of the first blind holes and the horizontal rows composed of the second blind holes are arranged alternately, and any first blind hole and the two second blind holes adjacent thereto on the other adjacent horizontal row constitute a first blind hole group. If a plurality of blind holes are arranged on the opposite two side surfaces of the current collector, the blind holes on the first surface or the second surface meet the above conditions, and further, the blind holes on both the first surface and the second surface meet the above conditions. It can be understood that adjacent first blind hole groups may share one or two second blind holes. At this time, in some specific embodiments, on the first surface or 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.

[0045] In some embodiments of the present 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 embodiment of the present 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 in 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 ratio of the second blind hole 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 ratios of the first blind hole and the second blind hole in the first blind hole group within the above ranges actually limits the distance between the edges of the first blind hole and the edges of the second blind hole in the first blind hole group. In this way, the distribution of the multiple first blind holes and the multiple second blind holes can be more reasonable, giving full play to the synergistic effect of the two, that is, fully reducing the interfacial impedance of the current collector in the first blind hole group and fully improving the adhesion between the current collector and the electrode material layer, thereby improving the overall comprehensive performance of the current collector and fully reducing the risk of overly dense blind hole arrangement affecting the mechanical properties of the current collector. Furthermore, in the plurality of first blind hole groups, the opening areas of the first blind holes account for the same proportion, and the opening areas of the second blind holes account for the same proportion.

[0046] In some specific embodiments, the lengths of the sides of the first triangle are each independently within the range of 100 μm to 500 μm, 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 lengths of the sides of the first triangle can each independently be 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, etc.

[0047] In some other embodiments of the present application, please refer to Figures 2-3. The first surface or the second surface has a plurality of second blind hole groups, each of the second blind hole groups includes 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. If a plurality of blind holes are arranged on the two opposite sides of the current collector, the blind holes on the first surface or the second surface meet the above conditions, and further, the blind holes on both the first surface and the second surface meet the above conditions. This arrangement can also improve the uniformity of the current collector, so that the current collector can uniformly reduce the interfacial impedance of the current collector 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.

[0048] In some embodiments of the present application, the side lengths of the second triangle are independently within the range of 100 μm to 500 μm. Specifically, the side lengths of the second triangle can be independently 100 μm, 150 μm, 200 μm, 250 μm, 300 μm, 350 μm, 400 μm, 450 μm, 500 μm, etc., as long as 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 surface of the current collector can have a suitable density of first and second blind holes, thereby improving the interface bonding performance and electronic conductivity of the current collector while also giving the current collector better mechanical properties.

[0049] In some embodiments of the present application, referring to FIG1B , the thickness of the current collector is h, 5 μm ≤ h ≤ 20 μm. For example, the thickness of the current collector may be, but is not limited to, 5 μm, 8 μm, 10 μm, 12 μm, 15 μm, 18 μm, 20 μm, etc.

[0050] In some embodiments of the present application, referring to FIG1B , the depths of the first blind hole (h1) and the second blind hole (h2) are each independently 1.5%-50% of the thickness of the current collector (h). In this way, the specific surface areas of the first blind hole and the second blind hole can be controlled within a suitable range, thereby further improving the interface bonding performance of the current collector, reducing the interface 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 independently be 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 thickness of the current collector (h).

[0051] In the embodiments of the present application, on a single surface of the current collector, the depths (h1) of the multiple first blind holes can be equal or unequal; the depths (h2) of the multiple second blind holes can be equal or unequal; and 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 two opposing surfaces 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.

[0052] In some specific embodiments of the present application, when the thickness h of the current collector is 8 μm, the depth of the first blind hole is h1, the depth of the second blind hole is h2, 0.2 μm ≤ h1 ≤ 4 μm, and 0.2 μm ≤ h2 ≤ 4 μm. For example, when the thickness h of the current collector 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, etc.

[0053] In other specific embodiments, when the thickness h of the current collector is 13 μm, 0.2 μm ≤ h1 ≤ 6.5 μm, and 0.2 μm ≤ h2 ≤ 6.5 μm. For example, when the thickness h of the current collector is 13 μm, the depth h1 of the first blind hole and the depth h2 of the second blind hole may 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.

[0054] In the embodiment of the present application, the distance d between the edge of the current collector and the edge of the outermost blind hole is 0.01mm≤d≤5mm. That is, by leaving a certain distance at the edge of the current collector without setting blind holes, the generation of burrs and burrs on the current collector can be effectively avoided, thereby 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.

[0055] In some embodiments of the present application, the aforementioned current collector preparation method includes providing a foil and mechanically pressing the foil to obtain the current collector provided in the embodiments of the present application. In some specific embodiments, the mechanical pressing involves pressing the foil with a roller having protrusions distributed on its surface to form blind holes in the foil surface. This preparation method has high process reliability, simple steps, high production efficiency, and a high product yield.

[0056] More importantly, during the above-mentioned molding process, the original foil at the blind hole position will be squeezed and accumulated on the hole wall of the blind hole, making the material density of the current collector at the blind hole wall and its vicinity greater than that at other positions (positions that do not contain blind holes and are at a certain distance from the blind hole wall). When the electrode material is coated on the surface of the current collector and the electrode plate is rolled, the current collector material density at the hole wall of the blind hole is relatively high, which has a certain buffering effect on the rolling force, thereby reducing the extension deformation of the hole wall of the blind hole when it is subjected to the rolling force, thereby further reducing the risk of the electrode material in the blind hole detaching from the blind hole, ensuring that the adhesion strength of the electrode material in the blind hole is high, thereby improving the peel strength of the final electrode plate and reducing the probability of the electrode plate falling off. In the prior art, when preparing a current collector with through holes, the foil at the target through holes is directly punched out, that is, the density of the through hole wall material does not change. When the electrode plate is rolled, there is no buffering effect when the through hole is subjected to the rolling force, the extension deformation at the through hole wall is large, and the risk of the electrode material in the through hole detaching from the through hole is greater, and the prepared electrode plate is more likely to fall off.

[0057] Accordingly, embodiments of the present application also provide an electrode plate, including the current collector provided in the embodiments of the present application. Due to the use of the current collector provided in the embodiments of the present application, the electrode plate has high peel strength and good structural stability during the battery cycle, which is conducive to improving the battery's cycling performance. At the same time, the electrode plate also has high electronic conductivity and ionic conductivity, which can improve the rate performance of the final battery.

[0058] The electrode sheet has a high peel strength, which can be understood as follows: when the thickness of the current collector and the thickness of the electrode material layer of the electrode sheet are equal, the peel strength of the electrode sheet provided in the embodiment of the present application is greater than that of the electrode sheet using a foil of the same thickness as the current collector. Alternatively, when the peel strength of the electrode sheet provided in the embodiment of the present application is equal to the peel strength of the electrode sheet using a foil of the same thickness as the current collector, the electrode material layer thickness of the electrode sheet of the embodiment of the present application is greater. Specifically, when the peel force of the positive electrode sheet is 15N, the thickness of the positive electrode material layer of the positive electrode sheet using foil as the current collector can reach up to 123μm, but when the current collector provided by the embodiment of the present application is used, the thickness of the positive electrode material layer can reach up to 126μm. Taking the negative electrode sheet as an example, when the peel force of the negative electrode sheet is 15N, the thickness of the negative electrode material layer of the negative electrode sheet using foil as the current collector can reach up to 170μm, but when the current collector provided by the embodiment of the present application is used, the thickness of the negative electrode material layer can reach up to 175μm.

[0059] The electrode plate provided in the embodiment of the present application can be a positive electrode plate or a negative electrode plate.

[0060] Accordingly, the present invention also provides a battery comprising the electrode plate provided in the present invention. Due to the use of the electrode plate, the battery has both good cycle performance and rate performance, and can achieve a higher energy density.

[0061] In the embodiment of the present application, the above-mentioned battery can be a liquid battery, a semi-solid battery or an all-solid battery.

[0062] In some embodiments of the present application, the battery includes a positive electrode sheet, a negative electrode sheet, and a separator and an electrolyte disposed between the positive electrode sheet and the negative electrode sheet.

[0063] In some other embodiments of the present application, the above-mentioned battery includes a positive electrode sheet, a negative electrode sheet, and a solid electrolyte arranged between the positive electrode sheet and the negative electrode sheet.

[0064] In the embodiments of the present application, the above-mentioned battery can be a lithium ion battery, a sodium ion battery, a potassium ion battery, a magnesium ion battery, etc., but is not limited thereto.

[0065] In the embodiment of the present application, the above-mentioned battery may use the current collector provided in the embodiment of the present application in the positive electrode sheet, or may use the current collector provided in the embodiment of the present application in the negative electrode sheet, or may use the current collector provided in the embodiment of the present application in both the positive electrode sheet and the negative electrode sheet.

[0066] The present invention also provides an electrical device including the battery provided in the present invention. The battery is used to power the electrical device. Due to the inclusion of the battery provided in the present invention, the electrical device has high market competitiveness.

[0067] In some embodiments of the present application, the above-mentioned electrical equipment includes but is not limited to 3C electronic products such as mobile phones, computers, laptops, smart watches, and powered vehicles. Among them, powered vehicles include but are not limited to new energy vehicles, power-assisted bicycles, etc.

[0068] The technical solution of this application is further illustrated below with multiple embodiments.

[0069] Example 1

[0070] A current collector having a first surface on which a plurality of cylindrical first blind holes each having a depth of 0.2 μm and a plurality of cylindrical second blind holes each having a depth of 0.2 μm are arranged in an array, wherein the first blind holes have a pore diameter of 50 μm and the second blind holes have a pore diameter of 10 μm. On the first surface of the current collector, the ratio of the number of the first blind holes to the number of the second blind holes is 1:8, and the combined open area of ​​the plurality of first blind holes and the plurality of second blind holes accounts for 15.0% of the area of ​​the first surface of the current collector.

[0071] The second surface, opposite the first surface, is similarly arranged with a plurality of cylindrical first blind holes with a depth of 0.2 μm and a plurality of cylindrical second blind holes with a depth of 0.2 μm. The first blind holes have a diameter of 50 μm, and the second blind holes have a diameter of 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 combined open area of ​​the plurality of first blind holes and the plurality of second blind holes accounts for 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 do not overlap with the orthographic projections of the blind holes on the second surface.

[0072] Example 2

[0073] The only difference from Example 1 is that the sum of the opening areas of the plurality of first blind holes and the plurality of second blind holes accounts for 78.5% of the first surface area of ​​the current collector.

[0074] The second surface array is composed of a plurality of cylindrical first blind holes with a depth of 0.1 μm and a plurality of cylindrical second blind holes with a depth of 0.1 μm. The aperture of the first blind holes is 40 μm, and the aperture 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 combined open area of ​​the plurality of first blind holes and the plurality of second blind holes accounts for 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 do not overlap with the orthographic projections of the blind holes on the second surface.

[0075] Example 3

[0076] 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 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 accounts for 47.0% of the first surface area of ​​the current collector.

[0077] The second surface is similarly arranged with 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 first blind holes have a diameter of 55 μm, and the second blind holes have a diameter of 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 combined open area of ​​the multiple first blind holes and the multiple second blind holes accounts for 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 do not overlap with the orthographic projections of the blind holes on the second surface.

[0078] Example 4

[0079] 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 accounts for 15.0% of the first surface area of ​​the current collector.

[0080] The second surface is similarly arranged with 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 first blind holes have a diameter of 60 μm, and the second blind holes have a diameter of 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 combined open area of ​​the multiple first blind holes and the multiple second blind holes accounts for 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 do not overlap with the orthographic projections of the blind holes on the second surface.

[0081] Example 5

[0082] 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 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 accounts for 15.0% of the first surface area of ​​the current collector.

[0083] The second surface is similarly arranged with 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 first blind holes have a diameter of 60 μm, and the second blind holes have a diameter of 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 combined open area of ​​the multiple first blind holes and the multiple second blind holes accounts for 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 do not overlap with the orthographic projections of the blind holes on the second surface.

[0084] Example 6

[0085] 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.

[0086] The second surface is similarly arranged with 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 first blind holes have a diameter of 100 μm, and the second blind holes have a diameter of 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 combined open area of ​​the multiple first blind holes and the multiple second blind holes accounts for 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 do not overlap with the orthographic projections of the blind holes on the second surface.

[0087] Example 7

[0088] 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.

[0089] The second surface is similarly arranged with 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 first blind holes have a diameter of 100 μm, and the second blind holes have a diameter of 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 combined open area of ​​the multiple first blind holes and the multiple second blind holes accounts for 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 do not overlap with the orthographic projections of the blind holes on the second surface.

[0090] Example 8

[0091] The only difference from the embodiment is that on the first surface of the current collector, the ratio of first blind holes to second blind holes is 1:2. Horizontal rows of first blind holes and horizontal rows of second blind holes are arranged alternately to form multiple first blind hole groups. The first triangles are isosceles triangles with angles of 120°, 30°, and 30°, respectively. In each first blind hole group, 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%.

[0092] The ratio of first blind holes to second blind holes on the second surface is 1:4. Horizontal rows of first blind holes and horizontal rows of second blind holes are arranged alternately to form multiple first blind hole groups. The first triangles are isosceles triangles, with angles of 120°, 30°, and 30°, respectively. In each first blind hole group, 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 do not overlap with those on the second surface.

[0093] Example 9

[0094] The only difference from Example 1 is that on the first 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 second blind hole groups, and the second triangles are isosceles triangles. The combined open area of ​​the multiple first blind holes and the multiple second blind holes accounts for 25% of the area of ​​the first surface of the current collector.

[0095] 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 second blind hole groups, and the second triangles are isosceles triangles. The combined opening area of ​​the multiple first blind holes and the multiple second blind holes accounts for 15% of the area of ​​the first surface of the current collector. Furthermore, the orthographic projections of the blind holes on the first surface do not overlap with the orthographic projections of the blind holes on the second surface.

[0096] Example 10

[0097] The difference from Example 1 is that the multiple blind holes are arranged only on the first surface of the current collector. That is, on the first surface of the current collector, 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 are arranged, wherein the aperture of the first blind holes is 50 μm and the aperture of the second blind holes is 10 μm. The ratio of the number of the first blind holes to the second blind holes is 1:8, and the combined opening area of ​​the multiple first blind holes and the multiple second blind holes accounts for 15.0% of the area of ​​the first surface of the current collector.

[0098] In order to highlight the beneficial effects of the embodiments of the present application, the following comparative examples are provided.

[0099] Comparative Example 1

[0100] Aluminum foil with a thickness of 8 μm was directly used as the current collector.

[0101] Comparative Example 2

[0102] A current collector having an array of multiple cylindrical blind holes with a depth of 0.2 μm and a pore size of 50 μm on one surface. The open area of ​​the multiple blind holes accounts for 15.0% of the area of ​​the one surface of the current collector. A second surface has an array of multiple cylindrical blind holes with a depth of 0.2 μm and a pore size of 50 μm. The open area of ​​the multiple blind holes accounts for 15.0% of the area of ​​the one surface of the current collector. Furthermore, the orthographic projection of the blind holes on the first surface does not overlap with the orthographic projection of the blind holes on the second surface.

[0103] Comparative Example 3

[0104] The differences from Example 1 are as follows: the first blind hole has a diameter of 120 μm, and the second blind hole has a diameter of 45 μm; on the second surface of the current collector, the first blind hole has a diameter of 120 μm, and the second blind hole has a diameter of 45 μm. Furthermore, the orthographic projections of the blind holes on the first surface do not overlap with the orthographic projections of the blind holes on the second surface.

[0105] Comparative Example 4

[0106] The differences from Example 1 are as follows: the first blind hole has a diameter of 35 μm, and the second blind hole has a diameter of 5 μm; on the second surface of the current collector, the first blind hole has a diameter of 35 μm, and the second blind hole has a diameter of 5 μm. Furthermore, the orthographic projections of the blind holes on the first surface do not overlap with the orthographic projections of the blind holes on the second surface.

[0107] Performance Testing

[0108] (1) Preparation of test cells:

[0109] Preparation of positive electrode sheet: The positive electrode active material (specifically Na 0.97 Ni0.34 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 on the surface of the positive electrode current collector (aluminum foil), dried, rolled, and cut to obtain a positive electrode sheet.

[0110] Preparation of negative electrode sheets: A negative electrode active material (specifically hard carbon), a conductive agent (specifically carbon black), and a binder (specifically aqueous carboxymethyl cellulose) with 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 ensured to be 177μm, of which the thickness of the negative electrode active material layer is 164μm. The thickness test of the negative electrode sheet: a film thickness meter is used to measure the thickness 5mm inward from the edge of the negative electrode sheet.

[0111] Battery Preparation: The positive and negative electrodes, along with the separator, are stacked, with the separator positioned between the positive and negative electrodes. The battery is then wound and filled with electrolyte. After formation and venting, the battery is obtained. The electrolyte salt (specifically, NaClO4) has a concentration of 1 mol / L, and the solvent is a 1:1 volume ratio mixture of ethylene carbonate (EC) and diethyl carbonate (DEC), which also contains 5 wt.% fluoroethylene carbonate.

[0112] (2) Peel strength test of the negative electrode sheets of each embodiment and comparative example: First, stick a double-sided tape in the center of a steel plate (300 mm long and 40 mm wide). Tear off the double-sided tape, and stick the negative electrode sheets (100 mm long and 10 mm wide) of each embodiment and comparative example prepared above, which are smaller than the size of the steel plate, on the tape. Then, place the steel plate with the fixed electrode sheet at 180° on the clamp of a universal tensile testing machine. After clearing, set the test width, the electrode sheet peeling length to 100 mm, the peeling speed to 50 mm / min, and start the test to obtain the peel strength curve and the average value. The peel strength test results of the negative electrode sheets prepared in each embodiment and comparative example are summarized in Table 1.

[0113] (3) Cycle test:

[0114] 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. The capacity at the first cycle was used as the initial capacity, and the capacity retention after 100 cycles was calculated using the following formula: Capacity retention after the nth cycle = (Discharge capacity after the nth cycle / Discharge capacity at the first cycle) * 100%. The corresponding capacity retention value was obtained by dividing the discharge capacity at the 100th cycle by the initial capacity. The results are summarized in Table 1.

[0115] (4) Rate performance test: At 25°C, the batteries prepared in the examples and comparative examples were charged to 3.9 V at a rate of 0.2C, and then discharged to 1.5 V at rates of 0.2C, 0.5C, 1C, 2C, and 3C, respectively. The discharge capacity at 0.2C in the first cycle was taken as the initial capacity, and the rate performance was calculated using the following formula: discharge capacity retention rate at a rate of 3C = (discharge capacity at 3C / discharge capacity at 0.2C)*100%.

[0116] (5) Energy density test: At room temperature (25℃±2℃), test according to the following steps: 1) discharge current at 1C to 1.5V and let it stand for 1 hour; 2) charge at 1C to 3.9V and let it 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 platform / weight.

[0117] Table 1

[0118] Combined with the data in Table 1, it can be seen that when the thickness of the negative electrode active material layer is equal, compared with the comparative example, the negative electrode sheet prepared by using the current collector provided in the embodiment of the present application has a higher peel strength, and the final battery has better cycle performance and rate performance, and also has a higher energy density.

[0119] The above is an exemplary embodiment of the present application. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made thereto without departing from the principles of the present application. These improvements and modifications are also considered to be within the scope of protection of the present application.

Claims

1. A current collector, wherein: The current collector is provided with a plurality of blind holes, the current collector has a first surface and a second surface arranged opposite to each other, 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 a first blind hole and a second blind hole, wherein the aperture of the first blind hole is D1, 50 μm≤D1≤100 μm; and the aperture of the second blind hole is D2, 10 μm≤D2≤30 μm.

2. The current collector according to claim 1, wherein: 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, wherein: Taking the sum of the opening areas of the plurality of blind holes on the first surface as a reference, 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%.

4. The current collector according to claim 1 or 2, wherein: On the first surface or the second surface, a plurality of the second blind holes are arranged around each of the first blind holes; and the ratio of the number of the first blind holes to the number of the second blind holes is in the range of 1:(2-8).

5. The current collector according to claim 1 or 2, wherein: The first surface or the second surface has a plurality of first blind hole groups, each of the first blind hole groups includes one first blind hole and two second blind holes adjacent to the first blind hole, and a line connecting the center of the first blind hole in the first blind hole group and the centers of the two second blind holes forms a first triangle; In the first triangle, the angle values ​​of the three corners are in the range of 15°-120°, wherein the angle value of the corner located at the first blind hole is 15°-120°, and the angle value of the corner located at the second blind hole is 15-85°.

6. The current collector according to claim 5, wherein: The first triangle is an isosceles triangle.

7. The current collector according to claim 5, wherein: In each of the first blind hole groups, the opening area of ​​the first blind holes accounts for 2.0%-44.6%, and the opening area of ​​the second blind holes accounts for 1.1%-8.9%.

8. The current collector according to claim 1 or 2, wherein: The first surface or the second surface has a plurality of second blind hole groups, each of the second blind hole groups includes three adjacent second blind holes and the first blind hole, and a 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; The second triangle is an isosceles triangle.

9. The current collector according to claim 8, wherein: The side lengths of the second triangles are each independently in the range of 100 μm to 500 μm.

10. The current collector according to claim 1 or 2, wherein: On the first surface or the second surface, the sum of the opening areas of the first blind holes and the 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, wherein: The depths of the first blind hole and the second blind hole are independently 1.5%-50% of the thickness of the current collector.

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

13. An electrode plate, wherein: The electrode plate comprises a current collector as described in any one of claims 1-12.

14. A battery, wherein: The battery comprises the electrode sheet as claimed in claim 13.

15. An electrical device, wherein: The electric device comprises the battery as claimed in claim 14.

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