Composite current collector, solid-state battery cell and battery module

Abstract

The utility model discloses a composite current collector, a solid-state battery cell and a battery module, and belongs to the technical field of solid-state batteries. The composite current collector comprises a composite body, a conductive connecting piece, a first metal layer and a second metal layer; the composite body comprises a first surface and a second surface which are oppositely arranged, a through hole is formed in one end of the composite body, and the through hole penetrates through the first surface and the second surface; the conductive connecting piece is arranged in the through hole; the first metal layer is arranged on the first surface of the composite body, the first metal layer covers an opening, facing the first surface, of the through hole, and the first metal layer is in contact with the conductive connecting piece; the second metal layer is arranged on the second surface of the composite body, covers the opening, facing the second surface, of the through hole, and is in contact with the conductive connecting piece. The composite current collector is simple in structure, light in weight, simple and quick to process, cost-saving and good in structural stability; and the solid-state battery core is formed by connecting in series and then in parallel, so that the formed solid-state battery core can be ensured to be high in voltage and high in capacitance.

Description

Technical Field

[0001] The utility model relates to the technical field of solid-state batteries, in particular to a composite current collector, a solid-state battery core and a battery module. Background Art

[0002] In lithium-ion solid-state batteries, the current collector plays a crucial role. It not only needs to provide an electron conduction path but also maintain structural stability during the charge and discharge process. Currently, bipolar current collectors are commonly used. Bipolar current collectors are a special current collector design that combines polymer layers, conductive particles, and metal layers.

[0003] However, due to the heavy weight, complex processing, and high cost of the bipolar current collector, the bipolar current collector has poor structural stability during the charge and discharge process, and the operating reliability of the lithium-ion solid-state battery cell cannot be guaranteed.

[0004] In response to the above problems, composite current collectors, solid-state battery cells and battery modules are urgently needed to solve the above problems. Utility Model Content

[0005] The purpose of the utility model is to provide a composite current collector, a solid-state battery cell and a battery module, so that the composite current collector has a simple structure, is light in weight, is easy and quick to process, saves costs and has good structural stability.

[0006] To achieve this purpose, the present invention adopts the following technical solutions:

[0007] A composite current collector is used in a solid-state battery cell, and the composite current collector comprises:

[0008] A composite body comprising a first surface and a second surface disposed opposite to each other, wherein a through hole is provided at one end of the composite body, and the through hole passes through the first surface and the second surface;

[0009] a conductive connecting member, disposed in the through hole;

[0010] a first metal layer disposed on the first surface of the composite body, the first metal layer covering the opening of the through hole toward the first surface, and the first metal layer in contact with the conductive connecting member;

[0011] The second metal layer is disposed on the second surface of the composite body, covers the opening of the through hole facing the second surface, and contacts the conductive connecting member.

[0012] As an alternative, on the first metal layer, a first portion covering the opening of the through hole facing the first surface is used for welding the tab, or on the second metal layer, a second portion covering the opening of the through hole facing the second surface is used for welding the tab.

[0013] As an alternative, the first metal layer is a copper foil or an aluminum foil, and the second metal layer is a copper foil or an aluminum foil.

[0014] A solid-state battery cell, comprising a plurality of battery cell units, the battery cell units comprising the composite current collector as described above, the battery cell units being connected in series and connected in parallel between each of the battery cell units.

[0015] As an alternative, the battery cell unit comprises:

[0016] A double-sided positive electrode sheet;

[0017] A double-sided negative electrode sheet, opposite to and spaced apart from the double-sided positive electrode sheet;

[0018] Positive and negative series-connected electrode sheets, connected in series between the double-sided positive electrode sheet and the double-sided negative electrode sheet;

[0019] A solid-state electrolyte, the solid-state electrolyte being provided between the adjacent double-sided positive electrode sheet and the positive and negative series-connected electrode sheets, between two adjacent positive and negative series-connected electrode sheets, and between the adjacent double-sided negative electrode sheet and the positive and negative series-connected electrode sheets, respectively.

[0020] As an alternative, a plurality of the positive and negative series-connected electrode sheets are provided, the plurality of positive and negative series-connected electrode sheets being connected in series between the double-sided positive electrode sheet and the double-sided negative electrode sheet, and the voltage of the battery cell unit being equal to the sum of the voltages of each of the positive and negative series-connected electrode sheets, and the capacitance of the battery cell unit being equal to the capacitance of the positive and negative series-connected electrode sheets.

[0021] As an alternative, between two adjacent battery cell units are connected in parallel through the double-sided positive electrode sheet or the double-sided negative electrode sheet to form the solid-state battery cell, and the capacitance of the solid-state battery cell is equal to the sum of the capacitances of each of the battery cell units, and the voltage of the solid-state battery cell is equal to the voltage of the battery cell unit.

[0022] As an alternative, the double-sided positive electrode sheet comprises:

[0023] The composite current collector;

[0024] A first active material layer, provided on the first metal layer, and a first portion of the first metal layer for welding the tab extending outside the first active material layer;

[0025] The second active material layer is disposed on one side of the second metal layer, and the second portion of the second metal layer for welding the tab extends outside the second active material layer. The first active material layer and the second active material layer are cathode materials.

[0026] As an alternative, the double-sided negative electrode sheet includes:

[0027] The composite current collector, and the portion of the composite body provided with the conductive connection member and the portion of the composite body provided with the conductive connection member in the double-sided positive electrode sheet are located on opposite sides;

[0028] The third active material layer is disposed on the first metal layer, and the first portion of the first metal layer for welding the tab extends outside the third active material layer;

[0029] The fourth active material layer is disposed on one side of the second metal layer, and the second portion of the second metal layer for welding the tab extends outside the fourth active material layer. The third active material layer and the fourth active material layer are anode materials.

[0030] As an alternative, the positive-negative series electrode sheet includes:

[0031] The composite current collector, and the composite body is not provided with the conductive connection member;

[0032] The fifth active material layer is disposed on the first metal layer, and the first metal layer is aligned with the end of the fifth active material layer;

[0033] The sixth active material layer is disposed on one side of the second metal layer, and the second metal layer is aligned with the end of the sixth active material layer. The fifth active material layer is a cathode material, and the sixth active material layer is an anode material.

[0034] The battery module includes a plurality of the above-mentioned solid-state battery cells.

[0035] The beneficial effects of the present utility model are:

[0036] By making the composite body include a relatively arranged first surface and a second surface, disposing a conductive connecting member in a through-hole at one end of the composite body, and then providing a first metal layer on the first surface of the composite body such that the first metal layer covers the opening of the through-hole facing the first surface and contacts the conductive connecting member, and at the same time providing a second metal layer on the second surface of the composite body such that the second metal layer covers the opening of the through-hole facing the second surface and contacts the conductive connecting member, the entire formed composite current collector is made conductive, ensuring that the composite current collector can provide an electron conduction path; by processing the composite current collector in the above manner, on the one hand, the structure of the composite current collector is simple, the weight is light, the processing is simple and fast, and the cost is saved; on the other hand, the structural stability of the composite current collector can be better, and it can be better applied to solid-state battery cells, ensuring the working reliability of the solid-state battery cells and battery modules.

[0037] The solid-state battery cells in the present utility model are formed by first connecting in series and then connecting in parallel. That is, first, a battery cell unit is formed by series connection to be able to increase the voltage of the battery cell unit; then, a plurality of formed battery cell units are connected in parallel with each other to form a solid-state battery cell to be able to increase the capacitance of the solid-state battery cell; thereby, it can be ensured that the voltage and capacitance of the formed solid-state battery cell are both high, and further, it can meet the usage scenarios of high voltage and high capacitance, ensuring a wide application range of the solid-state battery cell. Description of the Drawings

[0038] Figure 1 is a schematic structural diagram of the composite current collector provided by the present utility model;

[0039] Figure 2 is a schematic structural diagram of the solid-state battery cell provided by the present utility model.

[0040] Description of the Reference Numerals:

[0041] 10 - Solid-state battery cell;

[0042] 1 - Composite current collector; 11 - Composite body; 111 - First surface; 112 - Second surface; 113 - Through-hole; 12 - Conductive connecting member; 13 - First metal layer; 131 - First part; 14 - Second metal layer; 141 - Second part;

[0043] 2 - Battery cell unit; 21 - Double-sided positive electrode sheet; 211 - First active material layer; 212 - Second active material layer; 22 - Double-sided negative electrode sheet; 221 - Third active material layer; 222 - Fourth active material layer; 23 - Positive and negative series electrode sheet; 231 - Fifth active material layer; 232 - Sixth active material layer; 24 - Solid electrolyte. Detailed Embodiments

[0044] All features disclosed in this specification, or steps in all methods or processes disclosed, except for mutually exclusive features and / or steps, can be combined in any way.

[0045] Any feature disclosed in this specification, unless specifically stated, can be replaced by other equivalent or similar-purpose alternative features. That is, unless specifically stated, each feature is only an example of a series of equivalent or similar features. Throughout the specification, the same reference numerals indicate the same elements.

[0046] To make the technical problems solved, the technical solutions adopted, and the technical effects achieved by the present utility model clearer, the technical solutions of the present utility model will be further described below with reference to the drawings and through specific embodiments.

[0047] Currently, bipolar current collectors are usually used in solid-state battery cells. A bipolar current collector is a special current collector design that combines the designs of a polymer layer, conductive particles, and a metal layer. However, due to the relatively large weight, complex processing, high cost of the bipolar current collector, and poor structural stability of the bipolar current collector during charge and discharge processes, the working reliability of solid-state battery cells and battery modules cannot be guaranteed.

[0048] Embodiment 1

[0049] Therefore, in this embodiment, a composite current collector is proposed for use in solid-state battery cells. The composite current collector has a simple structure, a relatively light weight, simple and fast processing, cost savings, and good structural stability, and can be well applied to solid-state battery cells, thereby ensuring relatively high working reliability of solid-state battery cells and battery modules.

[0050] Specifically, as Figure 1 shown, the composite current collector 1 includes a composite body 11, a conductive connecting member 12, a first metal layer 13, and a second metal layer 14. Among them, the composite body 11 includes a first surface 111 and a second surface 112 arranged opposite to each other. A through hole 113 is provided at one end of the composite body 11, and the through hole 113 penetrates the first surface 111 and the second surface 112. The conductive connecting member 12 is disposed in the through hole 113. The first metal layer 13 is provided on the first surface 111 of the composite body 11. The first metal layer 13 covers the opening of the through hole 113 facing the first surface 111, and the first metal layer 13 is in contact with the conductive connecting member 12. The second metal layer 14 is provided on the second surface 112 of the composite body 11. The second metal layer 14 covers the opening of the through hole 113 facing the second surface 112, and the second metal layer 14 is in contact with the conductive connecting member 12. That is, the ends of the composite body 11, the first metal layer 13, and the second metal layer 14 are aligned.

[0051] In this embodiment, the composite current collector 1 changes the structural arrangement of the composite current collector 1 and the connection manner between each structure compared with the prior art; by making the composite body 11 include a first surface 111 and a second surface 112 arranged opposite to each other, and disposing the conductive connecting member 12 in the through hole 113 at one end of the composite body 11, and then disposing the first metal layer 13 on the first surface 111 of the composite body 11, so that the first metal layer 13 covers the opening of the through hole 113 facing the first surface 111 and contacts the conductive connecting member 12, and at the same time disposing the second metal layer 14 on the second surface 112 of the composite body 11, so that the second metal layer 14 covers the opening of the through hole 113 facing the second surface 112 and contacts the conductive connecting member 12, thereby making the entire formed composite current collector 1 conductive and ensuring that the composite current collector 1 can provide an electron conduction path; the composite current collector 1 is processed in the above manner, on the one hand, the structure of the composite current collector 1 is simple, the weight is light, the processing is simple and fast, and the cost is saved; on the other hand, the structural stability of the composite current collector 1 can be better, and it can be better applied to the solid-state battery cell 10, ensuring the working reliability of the solid-state battery cell 10 and the battery module.

[0052] Specifically, the composite body 11 includes a conductive agent, a binder, an active material, and metal powder; for the structural arrangement of the composite body 11, it can refer to the common current collector structure in the prior art, and here, the specific structural arrangement of the composite body 11 will not be described in detail.

[0053] Further, as Figure 1 shown, a tab is welded on the first part 131 of the first metal layer 13 covering the opening of the through hole 113 facing the first surface 111, so as to provide a weldable space for welding the tab through the first part 131 of the first metal layer 13 and ensure the smooth welding of the tab on the composite current collector 1; or a tab is welded on the second part 141 of the second metal layer 14 covering the opening of the through hole 113 facing the second surface 112, so as to provide a weldable space for welding the tab through the second part 141 of the second metal layer 14 and ensure the smooth welding of the tab on the composite current collector 1. Among them, both the first metal layer 13 and the second metal layer 14 are metal foils formed by rolling or electrolysis.

[0054] Specifically, the first metal layer 13 can be a copper foil or an aluminum foil, and the second metal layer 14 can be a copper foil or an aluminum foil. The specific types of the first metal layer 13 and the second metal layer 14 need to be determined according to the requirements of the positive and negative electrode settings. For example, when the formed composite current collector 1 is a positive electrode composite current collector, both the first metal layer 13 and the second metal layer 14 are aluminum foils; when the formed composite current collector 1 is a negative electrode composite current collector, both the first metal layer 13 and the second metal layer 14 are copper foils; when the formed composite current collector 1 is a positive and negative electrode composite current collector, one of the first metal layer 13 and the second metal layer 14 is a copper foil and the other is an aluminum foil.

[0055] As Figure 1 shown, the composite current collector 1 in this embodiment, by including the composite body 11, the first metal layer 13, the second metal layer 14, and the conductive connecting member 12, can ensure that the composite current collector 1 has electrical conductivity while making the structure of the composite current collector 1 simple, the processing convenient and fast, the cost low, and the structural stability of the composite current collector 1 good. And, through the first part 131 of the first metal layer 13 or the second part 141 of the second metal layer 14, a weldable space can be provided for the welding of the tab, ensuring the smooth welding of the tab on the composite current collector 1.

[0056] Embodiment 2

[0057] As Figure 1 and Figure 2 shown, a solid-state battery cell 10 and a battery module including a plurality of solid-state battery cells 10 are provided in this embodiment. The solid-state battery cell 10 includes a plurality of cell units 2. The cell units 2 include the composite current collector 1 in Embodiment 1. The cell units 2 are formed in series and are connected in parallel between each cell unit 2. In this embodiment, the battery module can specifically be a lithium-ion battery module.

[0058] The solid-state battery cell 10 in this embodiment is formed by first connecting in series and then connecting in parallel. That is, the cell units 2 are first formed by series connection to be able to increase the voltage of the cell units 2; then the formed plurality of cell units 2 are connected in parallel with each other to form the solid-state battery cell 10 to be able to increase the capacitance of the solid-state battery cell 10. Thus, it can be ensured that both the voltage and the capacitance of the formed solid-state battery cell 10 are relatively high, and further, the use scenarios of large voltage and high capacitance can be satisfied, ensuring a wide application range of the solid-state battery cell 10.

[0059] Further, as Figure 2As shown in the figure, the battery cell unit 2 includes a double-sided positive electrode sheet 21, a double-sided negative electrode sheet 22, a positive and negative series electrode sheet 23, and a solid electrolyte 24; among them, the double-sided negative electrode sheet 22 is opposite to and spaced from the double-sided positive electrode sheet 21; the positive and negative series electrode sheet 23 is serially connected between the double-sided positive electrode sheet 21 and the double-sided negative electrode sheet 22, and solid electrolytes 24 are respectively arranged between the adjacent double-sided positive electrode sheet 21 and the positive and negative series electrode sheet 23, between two adjacent positive and negative series electrode sheets 23, and between the adjacent double-sided negative electrode sheet 22 and the positive and negative series electrode sheet 23.

[0060] Specifically, as Figure 2 shown in the figure, the battery cell unit 2 is formed by serially connecting in a stacked manner, that is, the double-sided positive electrode sheet 21 and the double-sided negative electrode sheet 22 are respectively stacked on the opposite sides of the head and the tail, the positive and negative series electrode sheet 23 is stacked and serially connected in the middle of the double-sided positive electrode sheet 21 and the double-sided negative electrode sheet 22, and the solid electrolyte 24 is arranged, so that a battery cell unit 2 can be formed by serial connection.

[0061] Furthermore, as Figure 2 shown in the figure, in a battery cell unit 2, a plurality of positive and negative series electrode sheets 23 are provided, and the plurality of positive and negative series electrode sheets 23 are serially connected between the double-sided positive electrode sheet 21 and the double-sided negative electrode sheet 22 to form a battery cell unit 2, and the voltage of the formed battery cell unit 2 is equal to the sum of the voltages of each positive and negative series electrode sheet 23, and the capacitance of the battery cell unit 2 is equal to the capacitance of the positive and negative series electrode sheets 23.

[0062] For example, if the voltage between a pair of positive and negative electrodes is 3.6V and the capacitance is 1Ah, and six positive and negative series electrode sheets 23 are serially connected between the double-sided positive electrode sheet 21 and the double-sided negative electrode sheet 22, then the voltage of a formed battery cell unit 2 is 21.6V and the capacitance is 1Ah.

[0063] Furthermore, adjacent two battery cell units 2 are connected in parallel through the double-sided positive electrode sheet 21 or the double-sided negative electrode sheet 22 to form a solid-state battery 10, and the capacitance of the formed solid-state battery 10 is equal to the sum of the capacitances of each battery cell unit 2, and the voltage of the formed solid-state battery 10 is equal to the voltage of a battery cell unit 2.

[0064] Taking another example, after the battery cell units 2 with the above voltage of 21.6V and capacitance of 1Ah are formed, the formed battery cell units 2 are stacked in a parallel connection manner. For example, ten such battery cell units 2 are connected in parallel, and a solid-state battery 10 with a voltage of 21.6V and a capacitance of 10Ah can be formed, so as to ensure that the voltage and capacitance of the formed solid-state battery 10 are both relatively high.

[0065] It should be noted that the voltage of the solid-state battery cell 10 can be adaptively adjusted according to the number of positive and negative series electrode sheets 23 connected in series, ensuring that the voltage of the formed solid-state battery cell 10 meets the requirements; the capacitance of the solid-state battery cell 10 can be adaptively adjusted according to the number of battery cell units 2 connected in parallel, ensuring that the capacitance of the formed solid-state battery cell 10 meets the requirements.

[0066] In this embodiment, as Figure 2 shown, only one positive and negative series electrode sheet 23 is connected in series between the double-sided positive electrode sheet 21 and the double-sided negative electrode sheet 22 to form one battery cell unit 2, and at least two battery cell units 2 are connected in parallel to form one solid-state battery cell 10. Here, the specific number of series connections of the positive and negative series electrode sheets 23 and the specific number of parallel connections of the battery cell units 2 are not limited.

[0067] Specifically, as Figure 2 shown, the double-sided positive electrode sheet 21 includes the composite current collector 1, the first active material layer 211, and the second active material layer 212 in the first embodiment; wherein, the first active material layer 211 is disposed on the first metal layer 13 in the composite current collector 1, and the first part 131 of the first metal layer 13 for welding the tab extends outside the first active material layer 211; the second active material layer 212 is disposed on one side of the second metal layer 14 in the composite current collector 1, and the second part 141 of the second metal layer 14 for welding the tab extends outside the second active material layer 212. Both the first active material layer 211 and the second active material layer 212 are positive electrode materials to form the double-sided positive electrode sheet 21.

[0068] As Figure 2 shown, by making the first part 131 of the first metal layer 13 for welding the tab extend outside the first active material layer 211, a clearance space is formed between the first part 131 of the first metal layer 13 and the first active material layer 211, so as to ensure that the first active material layer 211 will not interfere with the operation of welding the tab on the first part 131 of the first metal layer 13, and ensure the simplicity, convenience, and smoothness of welding the tab on the first part 131.

[0069] As Figure 2 shown, by making the second part 141 of the second metal layer 14 for welding the tab extend outside the second active material layer 212, a clearance space is formed between the second part 141 of the second metal layer 14 and the second active material layer 212, so as to ensure that the second active material layer 212 will not interfere with the operation of welding the tab on the second part 141 of the second metal layer 14, and ensure the simplicity, convenience, and smoothness of welding the tab on the second part 141.

[0070] Furthermore, as Figure 2As shown in the figure, the double-sided negative electrode sheet 22 includes the composite current collector 1, the third active material layer 221, and the fourth active material layer 222 in the first embodiment; wherein, the part of the composite body 11 where the conductive connection member 12 is provided and the part of the composite body 11 where the conductive connection member 12 is provided in the double-sided positive electrode sheet 21 are located on opposite sides, so as to be conducive to the subsequent parallel connection of each formed battery cell unit 2; the third active material layer 221 is provided on the first metal layer 13 in the composite current collector 1, and the first part 131 of the first metal layer 13 for welding the tab extends outside the third active material layer 221; the fourth active material layer 222 is provided on one side of the second metal layer 14 in the composite current collector 1, and the second part 141 of the second metal layer 14 for welding the tab extends outside the fourth active material layer 222. Both the third active material layer 221 and the fourth active material layer 222 are negative electrode materials to form the double-sided negative electrode sheet 22.

[0071] It should be noted that in the double-sided negative electrode sheet 22, the first part 131 of the first metal layer 13 for welding the tab extends outside the third active material layer 221, and the second part 141 of the second metal layer 14 for welding the tab extends outside the fourth active material layer 222. The function produced by this technical feature is the same as that produced in the above-mentioned double-sided positive electrode sheet 21. Here, the function it produces will not be described in detail.

[0072] Furthermore, as Figure 2 shown, the positive and negative series-connected electrode sheet 23 includes the composite current collector 1, the fifth active material layer 231, and the sixth active material layer 232 in the first embodiment; wherein, the fifth active material layer 231 is provided on the first metal layer 13 in the composite current collector 1, and the first metal layer 13 is aligned with the end of the fifth active material layer 231; the sixth active material layer 232 is provided on one side of the second metal layer 14 in the composite current collector 1, and the second metal layer 14 is aligned with the end of the sixth active material layer 232. The fifth active material layer 231 is a positive electrode material, and the sixth active material layer 232 is a negative electrode material to form the positive and negative series-connected electrode sheet 23.

[0073] It should be noted that as Figure 2 shown, in the positive and negative series-connected electrode sheet 23, the conductive connection member 12 is not provided in the composite body 11, that is, the part of the composite body 11 for setting the through hole 113 is omitted; and the first metal layer 13 is aligned with the end of the fifth active material layer 231, that is, the first part 131 of the first metal layer 13 is omitted; and the second metal layer 14 is aligned with the end of the sixth active material layer 232, that is, the second part 141 of the second metal layer 14 is omitted, so that the formed positive and negative series-connected electrode sheet 23 has a simple and compact structure and occupies a small area.

[0074] It should be noted that since the positive and negative series electrodes 23 are connected in series between the double-sided positive electrode 21 and the double-sided negative electrode 22, so as to enable subsequent tab conduction connection through the composite current collectors 1 formed in the double-sided positive electrode 21 and the double-sided negative electrode 22. Therefore, forming the above-mentioned composite current collector 1 structure aligned with the fifth active material layer 231 and the sixth active material layer 232 in the positive and negative series electrodes 23 will not affect the parallel connection between the individual battery cell units 2, so as to ensure the conductivity of the formed battery cell units 2 and the entire solid-state battery 10.

[0075] In this embodiment, as Figure 2 shown, in a formed battery cell unit 2, a solid electrolyte 24 is provided between the fourth active material layer 222 and the fifth active material layer 231, a solid electrolyte 24 is provided between the sixth active material layer 232 and the first active material layer 211, and a solid electrolyte 24 is provided on one side of the second active material layer 212.

[0076] In this embodiment, by connecting a plurality of positive and negative series electrodes 23 in series between the double-sided positive electrode 21 and the double-sided negative electrode 22 to form a battery cell unit 2 in series connection, and the voltage of the battery cell unit 2 and the solid-state battery 10 can be adjusted by adjusting the number of series connections of the positive and negative series electrodes 23; then by connecting a plurality of battery cell units 2 in parallel to form a solid-state battery 10, and the capacitance of the solid-state battery 10 can be adjusted by adjusting the number of parallel connections of the battery cell units 2; thus, a solid-state battery 10 with a large voltage and high capacitance can be obtained, and furthermore, the designability of the voltage and capacitance of the solid-state battery 10 can be realized, reducing resource waste.

[0077] The above content is only the preferred embodiment of the present invention. For those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation manner and application scope. The content of this specification should not be construed as a limitation to the present invention.

Claims

1. A composite current collector, characterized in that, For use in a solid-state battery cell, the composite current collector includes: A composite body (11) including a first surface (111) and a second surface (112) arranged opposite to each other. One end of the composite body (11) is provided with a through hole (113) that penetrates the first surface (111) and the second surface (112); A conductive connecting member (12) disposed within the through hole (113); A first metal layer (13) provided on the first surface (111) of the composite body (11). The first metal layer (13) covers the opening of the through hole (113) facing the first surface (111), and the first metal layer (13) is in contact with the conductive connecting member (12); A second metal layer (14) provided on the second surface (112) of the composite body (11). The second metal layer (14) covers the opening of the through hole (113) facing the second surface (112), and the second metal layer (14) is in contact with the conductive connecting member (12).

2. The composite current collector according to claim 1, wherein A first portion (131) of the first metal layer (13) covering the opening of the through hole (113) facing the first surface (111) is used for welding a tab, or a second portion (141) of the second metal layer (14) covering the opening of the through hole (113) facing the second surface (112) is used for welding a tab.

3. The composite current collector according to claim 1, wherein The first metal layer (13) is a copper foil or an aluminum foil, and the second metal layer (14) is a copper foil or an aluminum foil.

4. Solid state battery cell, characterized in that, It includes a plurality of battery cell units (2). The battery cell units (2) include the composite current collector according to any one of claims 1-3. The battery cell units (2) are connected in series and are connected in parallel with each other.

5. The solid-state battery cell according to claim 4, characterized in that, The battery cell unit (2) includes: A double-sided positive electrode sheet (21); A double-sided negative electrode sheet (22) opposite to and spaced apart from the double-sided positive electrode sheet (21); Positive and negative series-connected electrode sheets (23) connected in series between the double-sided positive electrode sheet (21) and the double-sided negative electrode sheet (22); A solid electrolyte (24) is provided between the adjacent double-sided positive electrode sheet (21) and the positive and negative series-connected electrode sheet (23), between two adjacent positive and negative series-connected electrode sheets (23), and between the adjacent double-sided negative electrode sheet (22) and the positive and negative series-connected electrode sheet (23), respectively.

6. The solid-state battery cell according to claim 5, characterized in that, There are a plurality of the positive and negative series-connected electrode sheets (23). The plurality of positive and negative series-connected electrode sheets (23) are connected in series between the double-sided positive electrode sheet (21) and the double-sided negative electrode sheet (22). The voltage of the battery cell unit (2) is equal to the sum of the voltages of each positive and negative series-connected electrode sheet (23), and the capacitance of the battery cell unit (2) is equal to the capacitance of the positive and negative series-connected electrode sheets (23).

7. The solid-state battery cell according to claim 5, wherein Adjacent two of the battery cell units (2) are connected in parallel through the double-sided positive electrode sheet (21) or the double-sided negative electrode sheet (22) to form the solid-state battery cell, and the capacitance of the solid-state battery cell is equal to the sum of the capacitances of each of the battery cell units (2), and the voltage of the solid-state battery cell is equal to the voltage of the battery cell unit (2).

8. The solid-state battery cell according to any one of claims 5 to 7, characterized in that The double-sided positive electrode sheet (21) includes: The composite current collector; A first active material layer (211) disposed on the first metal layer (13), and a first portion (131) of the first metal layer (13) for welding the pole ear extends outside the first active material layer (211); A second active material layer (212) disposed on one side of the second metal layer (14), and a second portion (141) of the second metal layer (14) for welding the pole ear extends outside the second active material layer (212), and the first active material layer (211) and the second active material layer (212) are positive electrode materials.

9. The solid-state battery cell according to claim 8, wherein, The double-sided negative electrode sheet (22) includes: The composite current collector, and a portion of the composite body (11) provided with the conductive connection member (12) is located on opposite sides of the portion of the composite body (11) provided with the conductive connection member (12) in the double-sided positive electrode sheet (21); A third active material layer (221) disposed on the first metal layer (13), and a first portion (131) of the first metal layer (13) for welding the pole ear extends outside the third active material layer (221); A fourth active material layer (222) disposed on one side of the second metal layer (14), and a second portion (141) of the second metal layer (14) for welding the pole ear extends outside the fourth active material layer (222), and the third active material layer (221) and the fourth active material layer (222) are negative electrode materials.

10. The solid-state battery cell according to any one of claims 5-7, characterized in that, The positive and negative series electrode sheet (23) includes: The composite current collector, and the composite body (11) is not provided with the conductive connection member (12); A fifth active material layer (231) disposed on the first metal layer (13), and the first metal layer (13) is aligned with the end of the fifth active material layer (231); A sixth active material layer (232) disposed on one side of the second metal layer (14), and the second metal layer (14) is aligned with the end of the sixth active material layer (232), the fifth active material layer (231) is a positive electrode material, and the sixth active material layer (232) is a negative electrode material.

11. Battery module, characterized in that Including a plurality of solid-state battery cells as described in any one of claims 5-10.

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