Composite current collector and battery

Abstract

The utility model provides a composite current collector and a battery, which relates to the technical field of batteries and comprises a support layer and a metal layer. The supporting layer is made of polymer foam with pores, the composite current collector has a set thickness, and in the thickness direction of the composite current collector, the supporting layer is provided with a first supporting surface and a second supporting surface which are opposite to each other; a metal layer covers the first support surface and the second support surface. The battery provided by the utility model comprises the composite current collector in each embodiment. According to the composite current collector and the battery in the embodiment of the utility model, a composite structure of a multi-layer material can be utilized to further slow down the volume expansion of the lithium ion battery in the charging and discharging process and improve the mass energy density.

Description

TECHNICAL FIELD

[0001] The utility model relates to battery technology field, concretely relates to composite current collector and battery. BACKGROUND

[0002] In the related art, the energy density and the charging power of the lithium ion battery can be significantly improved by adding silicon material in the graphite anode, but it can cause the lithium ion battery to be more prone to swelling during charging and discharging, so that the pole piece structure is more prone to being damaged, affecting the overall life of the lithium ion battery. The prior art proposes to use foam metal as the current collector material in the pole piece structure to disperse the current density during charging and discharging to slow down the swelling phenomenon, but the density of the foam metal is large, which is not conducive to the improvement of the mass energy density. SUMMARY

[0003] The utility model discloses at least one of the technical problems existing in the prior art. To this end, the utility model provides a kind of current collector, which can slow down the volume expansion generated in the charging and discharging process of lithium ion battery, and improve the mass energy density of battery.

[0004] The utility model further provides a kind of lithium ion battery with the above-mentioned composite current collector.

[0005] According to the composite current collector of the first aspect embodiment of the utility model, it comprises: support layer and metal layer.

[0006] The support layer is made of polymer foam, the support layer has pores, the composite current collector has a set thickness, and the support layer has a first support surface and a second support surface opposite to each other in the thickness direction of the composite current collector.

[0007] The metal layer covers the first support surface and the second support surface.

[0008] According to the composite current collector of the utility model embodiment, at least has following beneficial effects:

[0009] When swelling phenomenon occurs in the charging and discharging process of the battery, the anode will extrude the composite current collector, and the composite current collector of the utility model utilizes the polymer foam with pores as the support layer to provide space for the overall deformation, so that the volume of the support layer decreases after being extruded, and the overall expansion of the battery is slowed down. Compared with the existing technology using metal foam to slow down the expansion, the density of the composite current collector of the utility model is lower, so that the total mass of the battery made of the composite current collector of the utility model decreases, and the mass energy density of the overall battery is higher.

[0010] According to some embodiments of the present application, the support layer has a first groove, the first groove forms a first notch at the first support surface, and the metal layer covers the inner wall surface of the first groove.

[0011] According to some embodiments of the present application, the support layer further has a second groove, the second groove forms a second notch at the second support surface, and the metal layer covers the inner wall surface of the second groove.

[0012] According to some embodiments of the present application, the support layer has a plurality of the first grooves, and / or the support layer has a plurality of the second grooves.

[0013] According to some embodiments of the present application, along the thickness direction of the composite current collector, the size of the support layer is H0, the recess depth of the first groove is H1, the recess depth of the second groove is H2, and H1+H2≥H0.

[0014] The support layer has a plurality of the first grooves and a plurality of the second grooves, the composite current collector has a projection plane perpendicular to the thickness direction, the contour of each first groove has a first projection on the projection plane, the contour of each second groove has a second projection on the projection plane, and the first projection partially overlaps with the second projection.

[0015] According to some embodiments of the present application, the support layer has a through hole, the through hole penetrates the first support surface and the second support surface, and the metal layer covers the inner wall surface of the through hole.

[0016] According to some embodiments of the present application, the porosity of the support layer is 30% to 60%.

[0017] According to some embodiments of the present application, in the thickness direction of the composite current collector, the ratio of the size of the support layer to the total size of the metal layer is 0.1 to 1.7.

[0018] According to some embodiments of the present application, the metal layer covers the first support surface and the second support surface through a vapor deposition process.

[0019] The battery according to the second aspect of the embodiments of the present application comprises:

[0020] The composite current collector according to any one of the above embodiments.

[0021] The battery according to the embodiments of the present application has at least the following beneficial effects:

[0022] When the expansion phenomenon occurs in the charging and discharging process, the composite current collector can slow down the expansion of the whole battery through the support layer, and strengthen the structure of the composite current collector itself, so that the internal structure of the battery is less likely to be damaged and has a longer service life. The composite current collector with lower density is also beneficial to improve the mass energy density of the battery.

[0023] Additional aspects and advantages of the present application will be in part apparent and in part pointed out hereinafter in the description of the application. BRIEF DESCRIPTION OF DRAWINGS

[0024] The present application will be further described below in conjunction with the drawings and examples, wherein:

[0025] Figure 1 A schematic diagram of the composite current collector for some embodiments of the first aspect of the present application;

[0026] Figure 2 A top view of the support layer for some embodiments of the second aspect of the present application;

[0027] Figure 3 A Figure 2 A cross-sectional view of A-A;

[0028] Figure 4 A cross-sectional view of the composite current collector for some embodiments of the third aspect of the present application;

[0029] Figure 5 A top view of the support layer for some embodiments of the fourth aspect of the present application;

[0030] Figure 6 A Figure 5 A cross-sectional view of B-B;

[0031] Figure 7 A cross-sectional view of the composite current collector for some embodiments of the fifth aspect of the present application;

[0032] Figure 8 A top view of the support layer for some embodiments of the sixth aspect of the present application;

[0033] Figure 9 A Figure 8 A cross-sectional view of C-C.

[0034] Reference signs:

[0035] Support layer 100, first support surface 110, second support surface 120, first recess 130, first notch 131, second recess 140, second notch 141, through hole 150;

[0036] Metal layer 200. DETAILED DESCRIPTION

[0037] The embodiments of the present application are described below in detail, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by reference to the drawings are exemplary only, and are used only for explaining the present application, and cannot be understood as a limitation of the present application.

[0038] In the description of the present application, it should be understood that, in relation to the orientation description, for example, the orientation or position relationship indicated by up, down, front, back, left, right, etc. is based on the orientation or position relationship shown in the drawings, and is only for the convenience of describing the present application and simplifying the description, and does not indicate or imply that the device or element indicated must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application.

[0039] In the description of the present application, the meaning of several is more than one, the meaning of multiple is more than two, greater than, less than, more than, etc. are understood as not including the number, above, below, etc. are understood as including the number. If it is described as first, second, it is only used for the purpose of distinguishing technical features, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the sequence of indicated technical features.

[0040] In the description of the present application, unless otherwise explicitly limited, the words such as setting, installing, connecting, etc. should be broadly understood, and the person skilled in the art can reasonably determine the specific meaning of the above words in the present application in combination with the specific content of the technical scheme.

[0041] In the description of the present application, the description of the reference terms "one embodiment", "some embodiments", "illustrative embodiment", "example", "specific example", or "some examples" means that the specific features, structures, materials or characteristics described in combination with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily mean the same embodiment or example. Moreover, the described specific features, structures, materials or characteristics can be combined in any one or more embodiments or examples in a suitable manner.

[0042] Please refer to Figure 1 As shown in the drawings, the present application provides a composite current collector, which comprises a support layer 100 and a metal layer 200.

[0043] The support layer 100 is made of polymer foam, and the support layer has pores. In order to facilitate the understanding of those skilled in the art, the polymer foam of the utility model can also be called polymer foaming material. The support layer 100 made of polymer foam is distributed with pores, and the pores are bubble-shaped structures. When the porosity is the same, the mass of the support layer 100 made of polymer foam is lower than that of the support layer 100 supported by the foam metal. Without departing from the inventive concept of the utility model, the material of the support layer 100 of the utility model can adopt various high molecular polymers, and specifically can be polypropylene foam, linear low-density polyethylene foam, polyolefin nanocomposite foam and the like.

[0044] The metal layer 200 of the utility model is used for bearing the active substance of the battery, so that the composite current collector can transmit the electrons generated by the electrochemical reaction of the battery through the current collector. The material of the metal layer 200 of the utility model can specifically be the single metal of copper, aluminum, nickel, iron and the like, can also be the compound of the above metal elements, and can also be the mixture of the above materials. Preferably, the metal layer 200 is made of copper single element. The metal layer 200 made of copper has better electrical conductivity, chemical stability, mechanical properties and economy, and is beneficial to the production of the composite current collector with lower cost and better battery performance.

[0045] Please refer to Figure 1 The thickness direction of the composite current collector (that is, the up-down direction in Figure 1 The support layer 100 of the utility model has the first support surface 110 and the second support surface 120 opposite to each other, and the metal layer 200 covers the first support surface 110 and the second support surface 120. In order to facilitate the understanding of those skilled in the art, the "covering the first support surface 110 and the second support surface 120" mentioned in the utility model should be understood as that the metal layer 200 is attached to the first support surface 110 and the second support surface 120, and the first support surface 110 and the second support surface 120 cannot be exposed outside the composite current collector.

[0046] The composite current collector of the utility model utilizes the polymer foam with pores to slow down the expansion phenomenon of the battery in the charging and discharging process. Specifically, when the expansion phenomenon occurs in the charging and discharging process of the battery, the anode will extrude the composite current collector, and the pores in the support layer 100 can provide space for the overall deformation of the support layer 100, so that the volume of the support layer 100 decreases after being extruded, and then the overall expansion of the battery is slowed down. Compared with the prior art of using metal foam to slow down the expansion, the composite current collector of the utility model directly utilizes the pores of the polymer foam itself to slow down the overall expansion of the battery. Under the premise that the porosity is the same, the density of the composite current collector of the utility model is lower, so that the total mass of the battery made of the composite current collector of the utility model decreases, and the mass energy density of the overall battery is higher.

[0047] On the other hand, since the support layer 100 is made of polymer foam, the support layer 100 has relatively small pits on the first support surface 110 and the second support surface 120, which are generated in the foaming process. The metal layer 200 covering the first support surface 110 and the second support surface 120 will extend into the pits, thereby enhancing the combination between the metal layer 200 and the support layer 100, further enhancing the structural stability of the composite current collector as a whole, and the pole piece structure is less likely to be damaged, and the overall service life of the battery is longer.

[0048] The person skilled in the art can select the method of covering the first support surface 110 and the second support surface 120 with the metal layer 200, such as magnetron sputtering, spraying, etc., but is not limited thereto.

[0049] As a preferred solution, in some embodiments, the metal layer 200 covers the first support surface 110 and the second support surface 120 by a vapor deposition process. Since the polymer foam has various functional groups, in the process of forming the metal layer 200 by the vapor deposition process, the material of the metal layer 200 can form coordination with the functional groups on the polymer foam. The coordination bond formed by coordination can further enhance the bonding force between the metal layer 200 and the composite current collector, enhance the structural stability of the composite current collector as a whole, reduce the deformation of the composite current collector as a whole, the pole piece structure is less likely to be damaged in the charging and discharging process of the battery, and the service life of the battery is longer.

[0050] Without departing from the inventive concept of the present application, the person skilled in the art can adjust the material of the metal layer 200 and the material of the support layer 100 according to the coordination relationship between the high molecular material and the metal in the prior art. Exemplarily, in some embodiments, the support layer 100 made of linear high molecular polymer foam contains amide groups; in the vapor deposition process, copper used to form the metal layer 200 can form coordination with the amide groups.

[0051] Without departing from the inventive concept of the present application, the present application does not limit the porosity of the polymer foam. As a preferred solution, in some embodiments, the porosity of the support layer 100 is less than or equal to 80%. The above solution can enable the support layer 100 to maintain a certain strength and rigidity, thereby enabling the formed pole piece to easily maintain a specific shape and facilitate processing.

[0052] Further, in some embodiments, the porosity of the support layer 100 is 30% to 60%. When the porosity of the support layer 100 is greater than or equal to 30%, the toughness of the support layer 100 is stronger, and the pores of the support layer 100 can provide more space for the overall deformation of the support layer 100, thereby further slowing down the expansion of the overall battery and more favorably further reducing the mass energy density of the overall battery. When the porosity of the support layer 100 is less than or equal to 60%, the support layer 100 can further maintain a certain strength and rigidity, thereby making the formed pole piece more easily maintain a specific shape and more convenient for processing.

[0053] Without departing from the inventive concept of the present application, those skilled in the art can also set the size ratio between the metal layer 200 and the support layer 100 by themselves. As a preferred solution, please refer to Figure 1 As shown in some embodiments, the ratio of the size of the support layer 100 to the total size of the metal layer 200 (i.e., the sum of the sizes of the metal layer 200 covering the first support surface 110 and the metal layer 200 covering the second support surface 120) in the thickness direction of the composite current collector is 0.1 to 1.7. When the ratio of the size of the support layer 100 to the total size of the metal layer 200 is greater than 0.1, the support layer 100 can have better expansion slowing capability; when the ratio of the size of the support layer 100 to the total size of the metal layer 200 is less than 1.7, the metal layer 200 can provide higher structural strength to the composite current collector, so that the pole piece formed by the composite current collector is easily maintained in a specific shape and is convenient for processing.

[0054] Specifically, in some embodiments, the size of the support layer 100 is 6 μm, the total size of the metal layer 200 is 4 μm, and the ratio of the size of the support layer 100 to the total size of the metal layer 200 is 1.5; in some embodiments, the size of the support layer 100 is 1 μm, the total size of the metal layer 200 is 9 μm, and the ratio of the size of the support layer 100 to the total size of the metal layer 200 is about 0.11; in some embodiments, the size of the support layer 100 is 5 μm, the total size of the metal layer 200 is 3 μm, and the ratio of the size of the support layer 100 to the total size of the metal layer 200 is about 1.67; in some embodiments, the size of the support layer 100 is 1 μm, the total size of the metal layer 200 is 7 μm, and the ratio of the size of the support layer 100 to the total size of the metal layer 200 is about 0.14. The proportional relationship in the above embodiments can further enable the composite current collector to have a certain effect of slowing down the overall expansion of the battery while taking into account its own strength. As a preferred solution, the ratio of the size of the support layer 100 to the total size of the metal layer 200 is 0.9 to 1.1.

[0055] Without departing from the inventive concept of the present application, the thickness of the support layer 100 and the thickness of the metal layer 200 are not limited, and a person skilled in the art can adjust them according to actual needs or in combination with other embodiments. In some embodiments, in the thickness direction of the composite current collector, the size of the support layer 100 is 2 to 6 μm, and the total size of the metal layer 200 is 2 to 4 μm.

[0056] It has been described above that the present application enhances the combination between the metal layer 200 and the support layer 100 through the pits distributed on the first support surface 110 and the second support surface 120. As a preferred scheme, a person skilled in the art can further process the first support surface 110 and the second support surface 120, and more notches, counterbores and grooves are arranged on the first support surface 110 and the second support surface 120, so that a part of the metal layer 200 can extend into and further combine with the support layer 100, thereby enhancing the structural strength of the composite current collector as a whole.

[0057] Please refer to Figure 2 、 Figure 3 、 Figure 4 , wherein Figure 2 In order to facilitate a person skilled in the art to understand the metal layer 200 of the composite current collector which is not shown, Figure 3 only the first notch 131 corresponding to one of the first grooves 130 is shown. As a preferred scheme, in some embodiments, the support layer 100 has the first grooves 130, the first grooves 130 form the first notches 131 on the first support surface 110, and the metal layer 200 covers the inner wall surface of the first grooves 130. During the process of covering the support layer 100, a part of the metal layer 200 can extend into the first grooves 130 and cover the inner wall surface of the first grooves 130, so that the structural strength of the composite current collector as a whole is higher. The first grooves 130 are more regular than other shapes, which is more conducive to the processing of the composite current collector.

[0058] It should be noted that the present application does not limit the length of the first grooves 130, and in addition to Figure 2 the length of the first grooves 130 shown, in some embodiments, the first grooves 130 extend to both sides of the support layer 100 in the width direction (refer to the left-right direction in Figure 2 ).

[0059] On the basis of the above embodiments, a person skilled in the art can adjust the shape of the metal layer 200 covering the inner wall surface of the first grooves 130 according to actual needs. Please refer to Figure 3 , in some embodiments, the metal layer 200 covers a certain thickness of metal according to the profile of the inner wall surface of the first grooves 130. Please refer to Figure 4As shown in some embodiments, a portion of the metal layer 200 completely fills the first groove 130. The metal layer 200 completely filling the first groove 130 has higher strength and rigidity, can further strengthen the structure of the composite current collector as a whole, and has stronger conductive performance. The above embodiments are all within the protection scope of the present application.

[0060] Further, please refer to Figure 2 , Figure 3 , Figure 4 As shown in some embodiments, the support layer 100 further has a second groove 140, the second groove 140 forms a second notch 141 on the second support surface 120, and the metal layer 200 covers the inner wall surface of the second groove 140. In the process of covering the support layer 100, on the premise that a portion of the metal layer 200 can extend into the first groove 130 and cover the inner wall surface of the first groove 130, another portion can further extend into the second groove 140 and cover the inner wall surface of the second groove 140, so that the structural strength of the composite current collector as a whole is higher.

[0061] It should be noted that the present application does not limit the length of the second groove 140, and in some embodiments, the second groove 140 extends to both sides of the support layer 100 in the width direction.

[0062] On the basis of the above embodiments, those skilled in the art can adjust the shape of the metal layer 200 covering the inner wall surface of the second groove 140 according to actual needs. Please refer to Figure 3 As shown in some embodiments, the metal layer 200 covers a certain thickness of metal according to the profile of the inner wall surface of the second groove 140. Please refer to Figure 4 As shown in some embodiments, a portion of the metal layer 200 completely fills the second groove 140. The metal layer 200 completely filling the second groove 140 has higher strength and rigidity, can further strengthen the structure of the composite current collector as a whole, and has stronger conductive performance. The above embodiments are all within the protection scope of the present application.

[0063] In particular, those skilled in the art can also adjust the shape of the metal layer 200 located in the first groove 130 and the second groove 140 respectively, and freely combine them. The above combinations are all within the protection scope of the present application.

[0064] Further, in some embodiments, the support layer 100 has a plurality of first grooves 130. In some embodiments, the support layer 100 has a plurality of second grooves 140. In some embodiments, the support layer 100 has a plurality of first grooves 130 and a plurality of second grooves 140. The plurality of grooves can further enhance the connection between the metal layer 200 and the support layer 100, so that the structural strength of the composite current collector as a whole is higher.

[0065] Please refer to Figure 1 , Figure 3 As shown, in some embodiments, in the thickness direction of the composite current collector (i.e., Figure 1 , Figure 3 In the vertical direction, the metal layers 200 located on both sides of the support layer 100 are separated by the support layer 100. Since the support layer 100 is made of porous polymer foam, and polymer foam has good insulation properties, the support layer 100 can reduce the possibility of short circuit in the metal layer 200 under conditions such as lithium plating and external impact, thereby improving the safety performance of the battery.

[0066] Please refer to Figure 8 , Figure 9 As shown, where Figure 8 To facilitate understanding by those skilled in the art, the metal layer 200 is not shown. In some embodiments, the support layer 100 has a through-hole 150 that penetrates the first support surface 110 and the second support surface 120. The metal layer 200 covers the inner wall of the through-hole 150. Since the through-hole 150 penetrates the first support surface 110 and the second support surface 120, the portion of the metal layer 200 covering the inner wall of the through-hole 150 can connect with the portions covering the first and second support layers 100, forming an integrally connected structure. This strengthens the connection between the metal layer 200 and the support layer 100, resulting in higher overall structural strength of the composite current collector. Furthermore, the portion of the metal layer 200 on the inner wall of the through-hole 150 allows for conductivity in the portions on the first and second support surfaces 110 and 120, further enhancing the conductivity of the current collector.

[0067] As previously described, in some embodiments, the support layer 100 is provided with a plurality of first grooves 130 and second grooves 140. Those skilled in the art can adjust the relevant dimensions of the first grooves 130 and second grooves 140. Specifically, please refer to... Figure 3 , Figure 4 As shown, along the thickness direction of the composite current collector, the dimension of the support layer 100 is H0, the recess depth of the first groove 130 is H1, and the recess depth of the second groove 140 is H2. Those skilled in the art can adjust H1 and H2 according to actual needs.

[0068] In some embodiments, the composite current collector has a projection plane perpendicular to the thickness direction, the contour of each first groove 130 has a first projection on the projection plane, the contour of each second groove 140 has a second projection on the projection plane, and the first projection and the second projection partially overlap.

[0069] Please refer to Figure 5 , Figure 6 , Figure 7 As shown, whereFigure 5 The second groove 140 recessed relative to the second support surface 120 is shown by a dashed line, and only the first slot 131 corresponding to one of the first grooves and the second slot 141 corresponding to one of the second grooves are shown. Figure 5 Figure 6 Figure 7 The sum of the recessed depth of the first groove 130 and the recessed depth of the second groove 140 is greater than the size of the support layer 100 (i.e. H1+H2≥H0) in the thickness direction of the composite current collector (i.e. the up-down direction of the first groove 130 and the second groove 140). The first groove 130 and the second groove 140 in the above embodiment can be connected to each other, thereby penetrating the support layer 100 in the thickness direction of the composite current collector. The part of the metal layer 200 connected to the first support layer 100 and the second support layer 100 through the first groove 130 and the second groove 140 can strengthen the connection between the metal layer 200 and the support layer 100, and the overall structural strength of the composite current collector is higher. On the other hand, the part not connected between the first groove 130 and the second groove 140 can provide a larger bonding area for the metal layer 200, further strengthening the overall structural strength of the composite current collector.

[0070] Based on the above embodiment, those skilled in the art can adjust the shape of the metal layer 200 covering the inner wall surface of the first groove 130 and the inner wall surface of the second groove 140 according to actual needs. Please refer to FIG. 2B, in some embodiments, the metal layer 200 covers a certain thickness of metal according to the profile of the inner wall surface of the first groove 130 and the inner wall surface of the second groove 140. Figure 6 Figure 7 In some embodiments, a part of the metal layer 200 completely fills the first groove 130 and the second groove 140. The metal layer 200 completely filling the first groove 130 and the second groove 140 has higher strength and rigidity, which can further strengthen the overall structure of the composite current collector and has stronger conductivity. The above embodiments are within the protection scope of the present application.

[0071] The present application also provides a battery, which comprises the composite current collector according to any one of the above embodiments. Since the composite current collector can slow down the overall expansion of the battery through the pores of the polymer foam, the internal structure of the battery is less likely to be damaged due to expansion, and the service life can be further prolonged. Compared with the battery using a foam metal as a current collector, under the premise of the same porosity, since the composite current collector of the present application has a lower density, the overall mass of the battery is reduced, and the mass energy density of the battery is higher.

[0072] ​​​On the other hand, since the support layer 100 is made of polymer foam, the support layer 100 is distributed with relatively small pits generated in the foaming process on the first support surface 110 and the second support surface 120, and the part of the metal layer 200 covering the first support surface 110 and the second support surface 120 will extend into the pits, thereby strengthening the combination between the support layer 100, further enhancing the structural stability of the composite current collector as a whole, the pole piece structure is less likely to be damaged, and the overall life of the battery is longer.

[0073] The embodiments of the utility model are explained in detail above in combination with the drawings, but the utility model is not limited to the above-mentioned embodiments, and various changes can be made within the knowledge range possessed by the ordinary skilled in the art without departing from the purpose of the utility model. In addition, the embodiments of the utility model and the features in the embodiments can be combined with each other without conflict.

Claims

1. A composite current collector, characterized by, The composite current collector comprises: a support layer made of a polymer foam, the support layer having pores, the composite current collector having a set thickness, the support layer having first and second support surfaces facing away from each other in the thickness direction of the composite current collector; a metal layer covering the first and second support surfaces.

2. The composite current collector of claim 1, wherein The support layer has first grooves forming first notches at the first support surface, the metal layer covering inner wall surfaces of the first grooves.

3. The composite current collector of claim 2, wherein, The support layer also has second grooves forming second notches at the second support surface, the metal layer covering inner wall surfaces of the second grooves.

4. The composite current collector of claim 3, wherein, The support layer has a plurality of the first grooves and / or a plurality of the second grooves.

5. The composite current collector of claim 3, wherein In the thickness direction of the composite current collector, the size of the support layer is H0, the depth of the first grooves is H1, the depth of the second grooves is H2, and H1+H2≥H0. The support layer has a plurality of the first grooves and a plurality of the second grooves, the composite current collector has a projection plane perpendicular to the thickness direction, the profile of each of the first grooves has a first projection on the projection plane, the profile of each of the second grooves has a second projection on the projection plane, and the first projection partially overlaps the second projection.

6. The composite current collector of claim 1, wherein The support layer has a through hole penetrating the first and second support surfaces, the metal layer covering inner wall surfaces of the through hole.

7. The composite current collector of claim 1, wherein The support layer has a porosity of 30% to 60%.

8. The composite current collector of claim 1, wherein In the thickness direction of the composite current collector, the ratio of the size of the support layer to the total size of the metal layer is 0.1 to 1.

7.

9. The composite current collector of any one of claims 1 to 8, wherein, The metal layer covers the first and second support surfaces by a vapor deposition process.

10. A battery characterized by The composite current collector according to any one of claims 1 to 9. The composite current collector according to any one of claims 1 to 9.

Images