Current collector, pole piece, battery cell and battery

Abstract

The current collector comprises a supporting layer and current collector layers, the supporting layer comprises a first surface and a second surface which are oppositely arranged, the current collector layers comprise a first current collector layer and a second current collector layer, the first current collector layer is arranged on the first surface, the second current collector layer is arranged on the second surface, and the first surface and the second surface are opposite to each other. A plurality of grooves are formed in the surface, deviating from the supporting layer, of the first current collector layer and / or the second current collector layer. According to the current collector provided by the utility model, the grooves are arranged on the first current collector layer and / or the second current collector layer, so that the specific surface area of the current collector can be increased, the contact area between a subsequently coated active material and the current collector is effectively increased, and the adhesion is improved, thereby solving the problems that the material is easy to fall off during the subsequent coating, and the coating is weak in adhesive force and easy to peel off.

Description

Technical Field

[0001] The utility model relates to the technical field of batteries, and particularly relates to a current collector, a pole piece, a battery cell and a battery. Background Art

[0002] With the rapid development of the new energy industry, the requirements for the comprehensive performance of batteries are increasing day by day. Among them, the battery pole piece is a key component affecting the battery performance. The battery pole piece generally includes a current collector and an active material layer provided on the surface of the current collector. At present, the current collectors in the industry are basically designed with uniform thickness. However, for such current collectors, there are problems such as easy material shedding during the subsequent active material coating process, weak coating adhesion, and the risk of easy peeling after multiple battery cycles. Summary of the Utility Model

[0003] The main object of the utility model is to propose a current collector, aiming to solve the technical problems of easy material shedding, weak coating adhesion and easy peeling during the subsequent coating of the current collector of the battery at present.

[0004] To achieve the above object, the utility model proposes a current collector, which includes:

[0005] A support layer, the support layer includes a first surface and a second surface arranged opposite to each other;

[0006] A current collector layer, the current collector layer includes a first current collector layer and a second current collector layer. The first current collector layer is arranged on the first surface, and the second current collector layer is arranged on the second surface; a plurality of grooves are provided on the surface of the first current collector layer and / or the second current collector layer facing away from the support layer.

[0007] In some embodiments, a plurality of the grooves are provided on the surface of the first current collector layer facing away from the support layer, and the depth of the grooves in the thickness direction of the first current collector layer is less than the thickness of the first current collector layer; and / or,

[0008] Taking the plane perpendicular to the thickness direction of the first current collector layer as the first projection plane, taking the positive projection area of the first current collector layer on the first projection plane as the area of the first current collector layer, and the total positive projection area of the grooves on the first projection plane is 10% - 90% of the area of the first current collector layer.

[0009] In some embodiments, a plurality of the grooves are provided on the surface of the second current collector layer facing away from the support layer, and the depth of the grooves in the thickness direction of the second current collector layer is less than the thickness of the second current collector layer; and / or,

[0010] Taking the plane perpendicular to the thickness direction of the second current collector layer as the second projection plane, taking the positive projection area of the second current collector layer on the second projection plane as the area of the second current collector layer, and the total area of the positive projection of the groove on the second projection plane is 10% - 90% of the area of the second current collector layer.

[0011] In some embodiments, the groove is in any one of the shapes of semi-circular, cylindrical, frustum-shaped, conical, square, and rectangular; and / or,

[0012] The grooves are evenly distributed on the surfaces of the first current collector layer and / or the second current collector layer.

[0013] In some embodiments, the first current collector layer is a positive electrode current collector material layer, and the second current collector layer is a negative electrode current collector material layer.

[0014] In some embodiments, the support layer is selected from insulating polymer layers.

[0015] The present invention also provides a pole piece, which includes an active material layer and a current collector. The current collector is the current collector as described above, and the active material layer is disposed on the surfaces of the first current collector layer and the second current collector layer that are away from the support layer.

[0016] In some embodiments, the active material layer includes a positive electrode active material layer and a negative electrode active material layer; the positive electrode active material layer is disposed on the surface of the first current collector layer that is away from the support layer, and the negative electrode active material layer is disposed on the surface of the second current collector layer that is away from the support layer.

[0017] The present invention also provides an electric core, which includes a positive electrode pole piece, a negative electrode pole piece, and a separator. The separator is sandwiched between the positive electrode pole piece and the negative electrode pole piece, and the positive electrode pole piece and / or the negative electrode pole piece is the pole piece as described above.

[0018] The present invention also provides a battery, which includes a housing and an electric core disposed in the housing. The electric core is the electric core as described above.

[0019] In the current collector of the technical solution of the present utility model, it includes a support layer and a current collector layer. Among them, the support layer includes a first surface and a second surface that are arranged facing away from each other; the current collector layer includes a first current collector layer and a second current collector layer. The first current collector layer is disposed on the first surface of the support layer, and the second current collector layer is disposed on the second surface of the support layer. A plurality of grooves are provided on the surface of the first current collector layer and / or the second current collector layer facing away from the support layer. This current collector can be applied to the preparation of electrode sheets. By providing a plurality of grooves on the surface of the first current collector layer and / or the second current collector layer facing away from the support layer, the surface thereof has an uneven morphology, which can increase the specific surface area of the current collector, thereby effectively increasing the contact area between the active material and the current collector during the coating process of electrode sheet preparation, improving the bonding effect, reducing the phenomena of delamination and powder falling between the active material and the current collector, improving the coating adhesion, and reducing the peeling risk of the coating after multiple cycles of the battery; moreover, by using this current collector, the undercoat can be eliminated in the subsequent electrode sheet preparation, reducing the production cost; in addition, through the above groove setting, the specific surface area of the current collector increases, which can increase the electron transmission path, and further improve the performance of the battery prepared using this current collector. Brief Description of the Drawings

[0020] Figure 1 It is a schematic structural diagram of the current collector in an embodiment of the present utility model;

[0021] Figure 2 It is a schematic structural diagram of the current collector in another embodiment of the present utility model;

[0022] Figure 3 It is a schematic structural diagram of the current collector in yet another embodiment of the present utility model;

[0023] Figure 4 It is a schematic structural diagram of the current collector in still another embodiment of the present utility model;

[0024] Figure 5 It is a schematic structural diagram of the electrode sheet in an embodiment of the present utility model.

[0025] Explanation of the Reference Numerals in the Drawings:

[0026] Reference numeral Name Reference numeral Name 100 Support layer 230 Groove 110 First surface 300 Active material layer 120 Second surface 310 Positive electrode active material layer 200 Current collector layer 320 Negative electrode active material layer 210 First current collector layer 220 Second current collector layer

[0027] The realization, functional features and advantages of the object of the present utility model will be further described in conjunction with the embodiments with reference to the drawings. Detailed Embodiment

[0028] Next, the solutions in the embodiments of the present utility model will be clearly and completely described in conjunction with the accompanying drawings in the embodiments of the present utility model. Obviously, the described embodiments are only a part of the embodiments of the present utility model, rather than all the embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present utility model.

[0029] It should be noted that all directional indications (such as up, down, left, right, front, back...) in the embodiments of the present utility model are only used to explain the relative position relationship and movement conditions between components in a specific posture (as shown in the accompanying drawings). If the specific posture changes, the directional indications will also change accordingly.

[0030] It should also be noted that when an element is referred to as "fixed to" or "disposed on" another element, it can be directly on the other element or there may be an intermediate element at the same time. When an element is referred to as "connected to" another element, it can be directly connected to the other element or there may be an intermediate element at the same time.

[0031] In addition, the descriptions involving "first", "second", etc. in the present utility model are only for descriptive purposes and cannot be understood as indicating or implying their relative importance or implicitly indicating the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include at least one of such features. In addition, the technical solutions between various embodiments can be combined with each other, but it must be based on the fact that those of ordinary skill in the art can implement them. When the combination of technical solutions results in contradictions or cannot be implemented, it should be considered that such a combination of technical solutions does not exist and is not within the protection scope required by the present utility model.

[0032] An embodiment of the present utility model provides a current collector. Refer to Figures 1 to 4 , the current collector includes a support layer 100 and a current collector layer 200. The support layer 100 includes a first surface 110 and a second surface 120 disposed opposite to each other. The current collector layer 200 includes a first current collector layer 210 and a second current collector layer 220. The first current collector layer 210 is disposed on the first surface 110 of the support layer 100, and the second current collector layer 220 is disposed on the second surface 120 of the support layer 100. A plurality of grooves 230 are provided on the surface of the first current collector layer 210 and / or the second current collector layer 220 facing away from the support layer 100.

[0033] Specifically, refer to Figure 1 and Figure 4 , in some embodiments, a plurality of grooves 230 are provided on the surfaces of the first current collector layer 210 and the second current collector layer 220 facing away from the support layer 100. In addition, refer to Figure 2 andFigure 3 , in some embodiments, a plurality of grooves 230 may also be provided only on the surface of the first current collector layer 210 or the second current collector layer 220 facing away from the support layer 100. The current collector can be applied to the preparation of battery electrodes. During the subsequent electrode preparation process, the surfaces of the first current collector layer 210 and the second current collector layer 220 of the current collector facing away from the support layer 100 are generally configured to coat active materials. By providing a plurality of grooves 230 on the surfaces of the first current collector layer 210 and / or the second current collector layer 220 facing away from the support layer 100 to make their surfaces uneven, the specific surface area of the current collector can be increased. During the subsequent coating process, the active materials are filled into the grooves 230, which can effectively increase the contact area between the active materials and the current collector during the coating process, improve the bonding effect, reduce the phenomena of delamination and powder shedding between the active materials and the current collector, effectively prevent the material from falling off, improve the coating adhesion, and reduce the peeling risk of the coating after multiple battery cycles. Moreover, by using this current collector, the bottom coating can be eliminated in the subsequent electrode preparation, reducing the production cost. In addition, by providing a plurality of grooves on the surface of the current collector layer, the specific surface area of the current collector increases, and during the subsequent coating process, the active materials are filled into the grooves. The active material layer is bonded to the current collector, and electrons are transmitted through the contact sites. At this time, the number of contact sites between the active materials and the current collector increases, thereby increasing the electron transmission path and further improving the performance of the battery prepared using this current collector. Among them, in order to fully improve the bonding effect and product performance of the current collector coating, preferably, a plurality of grooves 230 are provided on the surfaces of both the first current collector layer 210 and the second current collector layer 220 facing away from the support layer 100.

[0034] The grooves 230 are provided on the surfaces of the first current collector layer 210 and / or the second current collector layer 220 facing away from the support layer 100, and are generally designed not to penetrate the first current collector layer 210 and the second current collector layer 220, so as to increase the specific surface area of the current collector while reducing the resistivity. The grooves 230 are spaced apart on the first current collector layer 210 and the second current collector layer 220, and both the first current collector layer 210 and the second current collector layer 220 are continuous layers without interruption to ensure the integrity and effectiveness of the electron transmission path on the current collector.

[0035] In some embodiments, a plurality of grooves 230 are provided on the surface of the first current collector layer 210 facing away from the support layer 100. The depth of the grooves 230 in the thickness direction M of the first current collector layer 210 is less than the thickness of the first current collector layer 210; and / or, taking the plane perpendicular to the thickness direction M of the first current collector layer 210 as the first projection plane, taking the positive projection area of the first current collector layer 210 on the first projection plane as the area of the first current collector layer, the total positive projection area of the grooves 230 on the first projection plane is 10% - 90% of the area of the first current collector layer. By controlling the depth of the grooves 230 on the first current collector layer 210 as described above, and correlating and controlling the total positive projection area of the grooves 230 with the area of the first current collector layer, the size and distribution density of the grooves 230 can be controlled to a certain extent. Controlling them within the above range can effectively improve the bonding effect of the subsequent coating on the active material while ensuring the strength of the current collector layer.

[0036] Among them, the total positive projection area of the grooves 230 on the first projection plane is controlled to be 10% - 90% of the area of the first current collector layer. For example, it can be controlled to 10% - 40%, 40% - 90%, 40% - 60%, 55% - 90%, 50% - 80%. To improve the bonding effect between the coated active material and the current collector, the distribution density of the grooves 230 can be appropriately increased. For example, preferably, the total positive projection area of the grooves 230 on the first projection plane is controlled to be 55% - 90%, 60% - 80% or 75% - 85% of the area of the first current collector layer.

[0037] In some embodiments, the depth of the grooves 230 in the thickness direction M of the first current collector layer 210 is L11, and the thickness of the first current collector layer 210 is L12. The relationship between the depth L11 of the grooves 230 and the thickness L12 of the first current collector layer 210 can be controlled as: L11 = (1% - 95%) * L12, that is, the depth of the grooves 230 is controlled to be 1% - 95% of the thickness of the first current collector layer 210. For example, it can be controlled to 10% - 95%, 20% - 80%, 25% - 90%, 30% - 60%, 45% - 70%, 55% - 85%, or it can also be controlled to 5%, 15%, 35%, 50%, 65%, 75%, 92%, etc. To increase the specific surface area and enhance the bonding effect between the subsequent coating and the active material, preferably, on the premise of ensuring the strength of the current collector, the grooves 230 are designed to have a relatively deep depth. For example, the depth of the grooves 230 can be controlled to be 50% - 90%, 65% - 75% or 70% - 80% of the thickness of the first current collector layer 210.

[0038] In some embodiments, a plurality of grooves 230 are provided on the surface of the second current collector layer 220 facing away from the support layer 100. The size and distribution of the grooves 230 on the second current collector layer 220 can be designed with reference to the grooves 230 on the first current collector layer 210 in the above embodiments. They can be designed to be the same or similar to the grooves 230 on the first current collector layer 210, or they can be different.

[0039] Specifically, in some embodiments, a plurality of grooves 230 are provided on the surface of the second current collector layer 220 facing away from the support layer 100, and the depth of the grooves 230 in the thickness direction of the second current collector layer 220 is less than the thickness of the second current collector layer 220; and / or, taking the plane perpendicular to the thickness direction of the second current collector layer 220 as the second projection plane, taking the positive projection area of the second current collector layer 220 on the second projection plane as the area of the second current collector layer, the total area of the positive projections of the grooves 230 on the second projection plane is 10% - 90% of the area of the second current collector layer. For example, it can be controlled to be 10% - 30%, 30% - 50%, 40% - 90%, 55% - 85%, 65% - 80%, 70% - 90%. By controlling the size and distribution of the grooves 230 on the second current collector layer 220 to a certain extent, while ensuring the strength of the current collector layer, the bonding effect of the subsequent coating on the active material can be improved. In some embodiments, the depth of the grooves 230 in the thickness direction of the second current collector layer 220 is L21, and the thickness of the second current collector layer 220 is L22. The relationship between L21 and L22 can be controlled as: L21 = (1% - 95%) * L22, that is, the depth of the grooves 230 is 1% - 95% of the thickness of the second current collector layer 220. For example, it can be 35% - 80%, 40% - 85%, 55% - 90%, or it can also be controlled to be 5%, 10%, 25%, 45%, 50%, 65%, 70%, 75%, etc.

[0040] The shape of the grooves 230 can be set according to actual needs. For example, the grooves 230 can be designed to be any one of arc-shaped, semi-circular, cylindrical, frustum-shaped, conical, square, rectangular and other shapes. In addition, it can also be designed into other regular or irregular shapes, which are not limited herein. For example, referring to Figures 1 to 3 In some embodiments, the grooves can be rectangular; and referring to Figure 4 In some embodiments, the grooves 230 can also be designed to be arc-shaped.

[0041] In addition, referring to Figures 1 to 4, the groove 230 can be designed to be evenly distributed on the surface of the first current collector layer 210 and / or the second current collector layer 220. Through the uniform distribution design of the groove 230, the specific surface area of the current collector is evenly dispersed, the uniformity of the coating adhesion effect is improved, the material detachment is effectively prevented, the capacity loss is reduced, and the structural and performance stability of the product is enhanced. Of course, in some embodiments, the groove 230 may also be unevenly distributed on the surface of the first current collector layer 210 and / or the second current collector layer 220.

[0042] Referring to Figures 1 to 4 , in some embodiments, the shapes and sizes of the grooves 230 on the surfaces of the first current collector layer 210 and the second current collector layer 220 may be the same; relative to the second current collector layer 220, the shapes, sizes, and distributions of the grooves 230 provided on the surfaces of the first current collector layer 210 and the second current collector layer 220 may also be the same. Thus, a unified design of the grooves 230 on the first current collector layer 210 and the second current collector layer 220 can be achieved, improving the structural and performance stability; moreover, the unified structural design can simplify the production equipment, facilitate processing, and reduce the production cost. Of course, in some embodiments, the shapes and / or sizes of the grooves 230 on the surfaces of the first current collector layer 210 and the second current collector layer 220 may also be different; and / or, relative to the second current collector layer 220, the shapes, sizes, and distributions of the grooves 230 provided on the surfaces of the first current collector layer 210 and the second current collector layer 220 may also be different.

[0043] In some embodiments, the groove 230 is evenly distributed on the surface of the first current collector layer 210 and / or the second current collector layer 220, and the relationship between the spacing W1 of the groove 230 and the groove opening width W2 can be controlled as: W1 = (1% - 50%) * W2, that is, the spacing between adjacent grooves 230 is controlled to be (1% - 50%) of the groove opening width of the groove 230. For example, it can be controlled to 1% - 40%, 1% - 30%, 1% - 25%, 1% - 10%, 2% - 8%, 2 - 12%, 5% - 10%, 5% - 15%, 5% - 20%, 5% - 35%, 8% - 16%, 10% - 20%, 10% - 35%, 15% - 35%, 15% - 50%, 20% - 45%, 20% - 50%, or, it can also be controlled to 1%, 2%, 5%, 6%, 8%, 10%, 12%, 15%, 18%, 20%, 25%, 32%, 35%, 40%, 50%, etc.

[0044] There is no limit to the formation method of the groove 230 on the first current collector layer 210 and the second current collector layer 220. For example, it can be made by a specific topography roll through multiple repeated heat treatment rollings; or, the current collector layer can be first formed by electrolytic deposition, and then the current collector layer is chemically surface-treated to form grooves on its surface.

[0045] In some embodiments, the first current collector layer 210 is a positive current collector material layer, and the second current collector layer 220 is a negative current collector material layer, which can be configured as a bipolar current collector. Of course, in some embodiments, the materials of the first current collector layer 210 and the second current collector layer 220 can be selected according to actual needs. Specifically, if the current collector is used for battery pole sheet preparation, the materials of the first current collector layer 210 and the second current collector layer 220 are usually required to be inert with the active material to be coated on the current collector layer, and the materials of the first current collector layer 210 and the second current collector layer 220 can be selected based on this and its actual application.

[0046] The current collector of the embodiment of the utility model may be a positive electrode current collector or a negative electrode current collector. Among them, the support layer 100 can play an overall supporting role, and is configured to connect the first current collector layer 210 and the second current collector layer 220. To prevent internal short circuits, the support layer 100 generally uses an insulating material layer. Preferably, the support layer 100 uses an insulating polymer layer. For example, the insulating polymer layer can be selected from one or more of a polyethylene terephthalate layer, a polypropylene layer, a polyethylene layer, a polyimide layer, a polyamide layer, a polyacrylamide layer, a polycarbonate layer, and a polyurethane layer. In addition, other insulating polymer material layers can be selected according to actual needs. Using an insulating polymer layer as the support layer of the current collector, the high toughness of the insulating polymer can improve the impact resistance and nail penetration test pass rate of the battery cell, thereby improving the safety performance of the battery cell.

[0047] The utility model embodiment also provides a pole piece, referring to Figure 5 The electrode sheet includes an active material layer 300 and a current collector, and the current collector is as described above. Figure 1 In the current collector described in the embodiment shown, the active material layer 300 is disposed on the surface of the first current collector layer 210 and the second current collector layer 220 in the current collector away from the support layer 100. In some embodiments, the current collector in the pole piece can also adopt the current collector described in the other embodiments mentioned above. The specific structure of the current collector refers to the above embodiment. Since the pole piece adopts the current collector of the above embodiment, it at least has the technical effect corresponding to the technical solution of the adopted embodiment, and will not be repeated here one by one.

[0048] Reference Figure 5, in some embodiments, the active material layer 300 includes a positive electrode active material layer 310 and a negative electrode active material layer 320. The positive electrode active material layer 310 is disposed on the surface of the first current collector layer 210 facing away from the support layer 100, and the negative electrode active material layer 320 is disposed on the surface of the second current collector layer 220 facing away from the support layer 100. In this way, a bipolar electrode tab can be configured and formed. Moreover, the above tab production can use a single coater and oven for production, which can shorten the input cost of production equipment and improve production efficiency. Additionally, in some embodiments, the active material layer 300 includes a positive electrode active material layer 310 and a negative electrode active material layer 320. Preferably, the first current collector layer 210 is a positive electrode current collector material layer and the second current collector layer 220 is a negative electrode current collector material layer as described in the foregoing embodiments of the current collector. The positive electrode active material layer 310 is correspondingly disposed on the surface of the positive electrode current collector material layer, and the negative electrode active material layer 320 is correspondingly disposed on the surface of the negative electrode current collector material layer, thereby ensuring the electrochemical stability of the tab.

[0049] Of course, in other embodiments, on the premise of ensuring that the current collector layer 200 and the active material layer 300 are inert to each other when they are attached, the current collectors described in the foregoing other embodiments may also be used to configure the tab instead of the current collector configuration used in the above embodiments, or the current collectors described in the foregoing embodiments may be used to configure the tab with other active material layers. In addition, the tab of the embodiment of the present utility model may be a positive electrode tab or a negative electrode tab.

[0050] Referring to Figure 5 , in some embodiments, both the positive electrode active material layer 310 and the negative electrode active material layer 320 are single-layer active material layers. In some embodiments, the active material layers on both sides of the current collector may also be configured as double-layer active material layers or multi-layer active material layers, such as 3 layers, 4 layers, 6 layers, etc.; and the number of layers of the active material layers on both sides of the current collector may be the same or different.

[0051] The embodiment of the present utility model also provides an electric core, which includes a positive electrode tab, a negative electrode tab, and a separator. The separator is sandwiched between the positive electrode tab and the negative electrode tab, and the positive electrode tab and / or the negative electrode tab adopts the tab as described in the foregoing embodiments. The specific structure of the tab refers to the above embodiments. Since this electric core adopts all the technical solutions of all the above embodiments, it has at least all the technical effects brought by the technical solutions of the above embodiments, which will not be elaborated here one by one.

[0052] Specifically, in some embodiments, both the positive electrode tab and the negative electrode tab adopt the tab as described in Figure 5 the embodiments shown. When assembling the electric core, generally, the separator is sandwiched between the positive electrode active material layer of the positive electrode tab and the negative electrode active material layer of the negative electrode tab, or the separator is sandwiched between the negative electrode active material layer of the positive electrode tab and the positive electrode active material layer of the negative electrode tab to ensure electrochemical stability.

[0053] An embodiment of the present utility model further provides a battery, which includes a housing and an electric core disposed in the housing, and the electric core is the electric core described in the foregoing embodiment. For the specific structure of the electric core, reference may be made to the above embodiment. Since this battery adopts all the technical solutions of all the above embodiments, it has at least all the technical effects brought by the technical solutions of the above embodiments, and will not be elaborated herein one by one.

[0054] The above are only partial or preferred embodiments of the present utility model. Neither the text nor the drawings can limit the scope of protection of the present utility model. Any equivalent structural transformation made by using the content of the specification and drawings of the present utility model under the overall concept of the present utility model, or any direct / indirect application in other related technical fields is included in the scope of protection of the present utility model.

Claims

1. A current collector, characterized in that, Comprising: A support layer, the support layer including a first surface and a second surface arranged opposite to each other, and the support layer being selected from insulating polymer layers; A current collector layer, the current collector layer including a first current collector layer and a second current collector layer, the first current collector layer being disposed on the first surface, and the second current collector layer being disposed on the second surface; a plurality of grooves are provided on the surface of the first current collector layer and / or the second current collector layer facing away from the support layer.

2. The current collector according to claim 1, wherein A plurality of the grooves are provided on the surface of the first current collector layer facing away from the support layer, and the depth of the grooves in the thickness direction of the first current collector layer is less than the thickness of the first current collector layer; and / or, Taking the plane perpendicular to the thickness direction of the first current collector layer as the first projection plane, taking the orthographic projection area of the first current collector layer on the first projection plane as the area of the first current collector layer, and the total orthographic projection area of the grooves on the first projection plane is 10% - 90% of the area of the first current collector layer.

3. The current collector according to claim 2, wherein A plurality of the grooves are provided on the surface of the second current collector layer facing away from the support layer, and the depth of the grooves in the thickness direction of the second current collector layer is less than the thickness of the second current collector layer; and / or, Taking the plane perpendicular to the thickness direction of the second current collector layer as the second projection plane, taking the orthographic projection area of the second current collector layer on the second projection plane as the area of the second current collector layer, and the total orthographic projection area of the grooves on the second projection plane is 10% - 90% of the area of the second current collector layer.

4. The current collector according to claim 1, characterized in that, The grooves are in any one of the shapes of semi-circular, cylindrical, frustum-shaped, conical, and rectangular; and / or, The grooves are evenly distributed on the surface of the first current collector layer and / or the second current collector layer.

5. The current collector according to claim 1, characterized in that, The first current collector layer is a positive electrode current collector material layer, and the second current collector layer is a negative electrode current collector material layer.

6. A pole piece, characterized in that, Comprising an active material layer and a current collector, the current collector being the current collector according to any one of claims 1 to 5, and the active material layer being disposed on the surfaces of the first current collector layer and the second current collector layer facing away from the support layer.

7. The pole piece according to claim 6, wherein, The active material layer includes a positive electrode active material layer and a negative electrode active material layer; the positive electrode active material layer is disposed on the surface of the first current collector layer facing away from the support layer, and the negative electrode active material layer is disposed on the surface of the second current collector layer facing away from the support layer.

8. A battery cell, characterized in that, Comprising a positive electrode plate, a negative electrode plate, and a separator, the separator being clamped between the positive electrode plate and the negative electrode plate, and the positive electrode plate and / or the negative electrode plate being the electrode plate according to claim 6 or 7.

9. A battery, characterized in that, Comprising a housing and an electric core disposed in the housing, and the electric core being the electric core according to claim 8.

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