Functional current collector
By using a porous substrate layer and a through-structure current collector design in the battery, the problem of electrolyte wetting failure caused by mechanical stress in the cell is solved, thereby improving the cycle life and performance of the battery.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU ZHUOLI MEMBRANE MATERIAL TECHNOLOGY CO LTD
- Filing Date
- 2025-03-18
- Publication Date
- 2026-05-01
AI Technical Summary
During the charge and discharge cycle, the mechanical stress of the battery cell exceeds the bearing limit of the separator structure, causing the electrolyte to fail to wet and reducing the battery's cycle life.
A functional current collector is adopted, including a substrate layer and a conductive layer. The substrate layer has a porous structure, and the conductive layer is provided with through holes. The external space of the current collector is connected to the porous substrate through the through structure, so as to ensure that the electrolyte can be replenished to the active material and the separator when the cell expands.
The design of porous and through-structure increases the cycle life of the battery, replenishes the electrolyte, relieves internal pressure in the cell, and improves battery performance.
Smart Images
Figure CN224190940U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of current collector technology, and more particularly to a functional current collector. Background Technology
[0002] During charge-discharge cycles, the battery cell undergoes dynamic volume expansion and internal pressure fluctuations. This periodic mechanical stress accumulates over long-term cycling, causing the active materials to expand continuously and induce structural deformation. As a key medium for lithium-ion transport, the electrolyte is distributed within the micron-sized pores formed by the positive and negative electrode active materials and the separator, and its uniformity of penetration has a decisive impact on the battery's cycle performance.
[0003] However, under repeated volumetric deformation of the battery cell, the electrolyte undergoes localized migration, forming a non-equilibrium state where dry and enriched regions coexist. This is especially true when using silicon-based (Si / C, SiO) batteries. x In high-capacity anode systems, the volume expansion rate of over 300% significantly compresses the membrane pores. When the mechanical stress exceeds the structural bearing limit of the membrane (typically with an elastic modulus < 1 GPa), it will cause pore collapse and even form ion transport dead zones. This irreversible damage to the microstructure will exacerbate electrolyte wetting failure and induce a chain reaction of lithium dendrite growth and intensified interfacial side reactions, reducing battery cycle life. Utility Model Content
[0004] The technical problem this invention aims to solve is that when the mechanical stress on the battery cell exceeds the structural bearing limit of the separator, the resulting irreversible damage will exacerbate electrolyte wetting failure and reduce battery cycle life.
[0005] Therefore, this utility model provides a functional current collector.
[0006] The technical solution adopted by this utility model to solve its technical problem is:
[0007] A functional current collector, comprising,
[0008] A substrate layer, the substrate layer comprising a thin film having a porous structure;
[0009] A first conductive layer is disposed on one side of the substrate layer;
[0010] A second conductive layer is disposed on the other side of the substrate layer;
[0011] The through-hole is disposed on at least one of the first conductive layer and the second conductive layer. The diameter of the through-hole is R. The diameter of the thin film in the substrate layer is r. The ratio of R:r is in the range of 1:1 to 100:1. Some or all of the through-holes are opposite to the pores on the substrate layer.
[0012] Furthermore, the R:r ratio ranges from 5:1 to 50:1.
[0013] Furthermore, the aperture R of the through hole is between 0.05 μm and 5 μm.
[0014] Furthermore, the porosity of the vias on the first or second conductive layer is 1% to 50%.
[0015] Furthermore, an adhesive layer is provided between the first conductive layer, the second conductive layer, and the substrate layer.
[0016] Furthermore, the adhesive layer material is selected from at least one of modified PE, modified PP, and polyurethane, and a combination of at least one of epoxy curing agent and cyanate ester curing agent.
[0017] Furthermore, the adhesive layer material is selected from one of metal nitrides and metal borides.
[0018] Furthermore, a through hole is provided on the adhesive layer corresponding to the first or second conductive layer where the through hole is provided, and the through hole is disposed opposite to the through hole.
[0019] Furthermore, the porosity of the film is P, which is between 30% and 95%.
[0020] Furthermore, the pore size r of the upper pores of the film is 0.01 μm to 1 μm.
[0021] The beneficial effects of this utility model are that a porous structure is provided on the substrate layer and a through structure is provided on the conductive layer. The external space of the through structure is connected to the electrolyte in the porous structure of the substrate layer. After the cell expands in the later stage, the electrolyte in the pore structure of the porous substrate is squeezed into the active material and the separator, replenishing the electrolyte consumed during the cycle and increasing the cycle life of the battery. Attached Figure Description
[0022] The present invention will be further described below with reference to the accompanying drawings and embodiments.
[0023] Figure 1 This is a schematic diagram of the structure of the functional current collector in this utility model.
[0024] In the figure: 01, substrate layer; 02, first adhesive layer; 03, second adhesive layer; 04, first conductive layer; 05, second conductive layer; 06, through structure. Detailed Implementation
[0025] The present invention will now be described in further detail with reference to the accompanying drawings. These drawings are simplified schematic diagrams, illustrating only the basic structure of the present invention, and therefore only show the components relevant to the present invention.
[0026] In the description of this utility model, it should be understood that the terms "center," "longitudinal," "transverse," "length," "width," "thickness," "upper," "lower," "front," "rear," "left," "right," "vertical," "horizontal," "top," "bottom," "inner," "outer," "clockwise," "counterclockwise," "axial," "radial," and "circumferential," etc., indicating the orientation or positional relationship shown in the accompanying drawings, are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this utility model. Furthermore, features defined with "first" or "second" may explicitly or implicitly include one or more of that feature. In the description of this utility model, unless otherwise stated, "a plurality of" means two or more.
[0027] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0028] A functional current collector includes a substrate layer 01, an adhesive layer, and a conductive layer. The conductive layer is bonded to both sides of the substrate layer 01 by the adhesive layer. Specifically, along the thickness direction of the current collector, the current collector sequentially includes a first conductive layer 04, a first adhesive layer 02, a substrate layer 01, a second adhesive layer 03, and a second conductive layer 05.
[0029] The substrate layer 01 comprises one or more thin films with a porous structure. The thickness of the substrate layer 01 is between 2 μm and 30 μm, the porosity of the film is P, which is between 30% and 95%, preferably between 40% and 90%, and the pore size of the film is between 0.01 μm and 1 μm. The material of the substrate layer 01 is at least one of PE, PP, PET, and PI.
[0030] The adhesive layer material is selected from at least one of modified PE, modified PP, and polyurethane, and a combination of at least one of epoxy curing agent and cyanate ester curing agent; or the adhesive layer material may also be one of metal nitride and metal boride. The thickness of the adhesive layer is 0.1 μm to 2 μm.
[0031] The conductive layer is selected from at least one of aluminum, nickel, copper, stainless steel, and conductive carbon materials, and the thickness of the conductive layer is 0.1μm to 5μm, preferably 0.5μm to 2μm.
[0032] At least one of the first conductive layer 04 and the second conductive layer 05 is provided with a through hole. Due to the material used in the adhesive layer, the adhesive layer can be swollen by the electrolyte during the plating of the conductive layer. The swollen adhesive layer has the function of electrolyte transport, thereby connecting the external space of the current collector and the pore structure of the porous substrate with the through hole on the conductive layer.
[0033] It should be noted that some or all of the through holes are opposite to the pores on the substrate layer. When all the through holes are opposite to the pores on the substrate layer, the current collector's mechanical properties are slightly worse, but the processing cost can be reduced.
[0034] Preferably, when a through hole is provided on the first conductive layer 04, a through hole opposite to the through hole on the first conductive layer 04 may also be provided on the first adhesive layer 02. When a through hole is provided on the second conductive layer 05, a through hole opposite to the through hole on the second conductive layer 03 may also be provided on the second adhesive layer 03. The through hole and the through hole constitute a through structure 06. The through structure 06 connects the external space of the current collector and the pore structure of the porous substrate.
[0035] The pore size of the through-structure 06 is between 0.05 μm and 5 μm, preferably between 0.1 μm and 1 μm. Both the through-holes and vias in the through-structure 06 are pore-like, and their pore size is R. The pore size of the thin film in the substrate layer 01 is r, and the R:r ratio ranges from 1:1 to 100:1, preferably from 5:1 to 50:1. For example, when the pore size of the thin film in the substrate layer 01 is 40 nm, the pore size of the via can be 200 nm, 1000 nm, or 2000 nm. The porosity of the through-holes on the surface of the first conductive layer 04 or the second conductive layer 05 is 1% to 50%, preferably 2% to 10%. It should be noted that a low porosity in the through-holes on the conductive layer results in better conductivity, while a high porosity results in poorer conductivity.
[0036] The through-structure 06 can be achieved by acid corrosion, alkaline corrosion, electrochemical corrosion, or laser drilling.
[0037] Example 1
[0038] In this embodiment, the current collector includes, along its thickness direction, an aluminum conductive layer, an adhesive layer, a PE porous substrate, an adhesive layer (through-hole), and an aluminum conductive layer (through-hole). The substrate layer 01 has a film pore size of 0.05 μm and a porosity of 40.4%. The through-hole structure 06 has a pore size of 0.55 μm and a porosity of 50%. The through-hole structure 06 is processed by laser drilling.
[0039] Example 2
[0040] In this embodiment, the current collector comprises, along its thickness direction, an aluminum conductive layer (through-through) - an adhesive layer (through-through) - a PP porous substrate - an adhesive layer (through-through) - an aluminum conductive layer (through-through). The substrate layer 01 has a film pore size of 0.056 μm and a porosity of 60%. The through-structure 06 has a pore size of 0.12 μm and a porosity of 18%. The through-structure 06 is processed by laser drilling.
[0041] Example 3
[0042] In this embodiment, the current collector includes, along its thickness direction, a copper conductive layer, an adhesive layer, a PE porous substrate, an adhesive layer (through-hole), and a copper conductive layer (through-hole). The substrate layer 01 has a film pore size of 0.042 μm and a porosity of 39.5%. The through-hole structure 06 has a pore size of 0.82 μm and a porosity of 15%. The through-hole structure 06 is processed by laser drilling.
[0043] Example 4
[0044] In this embodiment, the current collector includes, along its thickness direction, an aluminum conductive layer, an adhesive layer, a PI porous substrate, an adhesive layer, and an aluminum conductive layer (through). The substrate layer 01 has a film pore size of 0.098 μm and a porosity of 88%. The through structure 06 has a pore size of 0.22 μm and a porosity of 10%. The through structure 06 is processed by laser drilling.
[0045] Example 5
[0046] In this embodiment, the current collector includes, along its thickness direction, an aluminum conductive layer (through-hole) - an adhesive layer - a PP porous substrate - an adhesive layer - an aluminum conductive layer (through-hole). The substrate layer 01 has a film pore size of 0.078 μm and a porosity of 63.5%. The through-hole structure 06 has a pore size of 0.3 μm and a porosity of 5%. The through-hole structure 06 is processed by an alkaline etching thinning method.
[0047] Example 6
[0048] In this embodiment, the current collector includes, along its thickness direction, an aluminum conductive layer (through-hole) - an adhesive layer - a PE porous substrate - an adhesive layer - an aluminum conductive layer (through-hole). The substrate layer 01 has a film pore size of 0.056 μm and a porosity of 40.4%. The through-hole structure 06 has a pore size of 0.23 μm and a porosity of 8%. The through-hole structure 06 is processed by alkaline etching for thinning combined with drilling.
[0049] Example 7
[0050] In this embodiment, the current collector includes, along its thickness direction, an aluminum conductive layer (through-hole) - an adhesive layer - a PP porous substrate - an adhesive layer - an aluminum conductive layer (through-hole). The substrate layer 01 has a film pore size of 0.068 μm and a porosity of 60%. The through-hole structure 06 has a pore size of 0.42 μm and a porosity of 45%. The through-hole structure 06 is processed by laser drilling.
[0051] Example 8
[0052] In this embodiment, the current collector comprises, along its thickness direction, an aluminum conductive layer (through-through) - an adhesive layer (through-through) - a PP porous substrate - an adhesive layer (through-through) - an aluminum conductive layer (through-through). The substrate layer 01 has a film pore size of 0.05 μm and a porosity of 39.5%. The through-structure 06 has a pore size of 2.5 μm and a porosity of 5%. The through-structure 06 is processed by laser drilling.
[0053] Comparative Example 1
[0054] In this embodiment, the current collector is aluminum foil.
[0055] Comparative Example 2
[0056] In this embodiment, the current collector includes, along its thickness direction, an aluminum conductive layer, an adhesive layer, a PET porous substrate, an adhesive layer, and an aluminum conductive layer in sequence, with the substrate layer 01 having a non-porous structure.
[0057] Table 1. Parameters of the current collector in Examples 1-7 and Comparative Examples 1 and 2.
[0058]
[0059]
[0060] Examples 1 to 8 exhibit a certain degree of air permeability, with Example 8 exhibiting particularly good air permeability. Its porous substrate has internal and external connections that are either interconnected or semi-connected. The porous substrate and the through-structure not only store electrolyte but also, under pressure, allow the electrolyte in the pores to replenish the pores of the electrode material and the diaphragm, thus replenishing the electrolyte for the battery cell. Comparative Examples 1 and 2 lack this function. A comparison of Examples 1 and 7 with Examples 2 to 6 reveals that excessively high surface porosity of the through-structure leads to poor conductivity. Therefore, the surface porosity of the through-holes needs to be limited to the range specified in this method.
[0061] In summary, in this application, the porous substrate not only buffers the internal pressure of the battery cell but also stores the electrolyte, and the through-structure allows the electrolyte to pass through the porous structure. During the later stages of cell expansion, the electrolyte in the pores of the porous substrate is squeezed into the active material and separator, replenishing the electrolyte consumed during cycling and increasing the battery's cycle life.
[0062] Based on the above-described preferred embodiments of this utility model, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the technical concept of this utility model. The technical scope of this utility model is not limited to the contents of the specification, but must be determined by the scope of the claims.
Claims
1. A functional current collector characterized by, include, The substrate layer (01) includes a thin film having a porous structure; A first conductive layer (04) is disposed on one side of a substrate layer (01); A second conductive layer (05) is disposed on the other side of the substrate layer (01); The through-hole is disposed on at least one of the first conductive layer (04) and the second conductive layer (05), and the diameter of the through-hole is R. The diameter of the thin film in the substrate layer (01) is r. The ratio of R:r is in the range of 1:1 to 100:
1. Some or all of the through-holes are opposite to the pores on the substrate layer.
2. The functional fluid of claim 1, wherein, The R:r ratio ranges from 5:1 to 50:
1.
3. The functional fluid of claim 1, wherein, The diameter R of the through hole is between 0.05 μm and 5 μm.
4. The functional current collector according to claim 1, characterized in that, The porosity of the vias on the first conductive layer (04) or the second conductive layer (05) is 1% to 50%.
5. The functional current collector according to claim 1, characterized in that, An adhesive layer is provided between the first conductive layer (04), the second conductive layer (05) and the substrate layer (01).
6. The functional current collector according to claim 5, characterized in that, The adhesive layer material is selected from at least one of modified PE, modified PP, and polyurethane, and a combination of at least one of epoxy curing agent and cyanate ester curing agent.
7. The functional current collector according to claim 5, characterized in that, The adhesive layer material is selected from one of metal nitrides and metal borides.
8. The functional current collector according to claim 5, characterized in that, A through hole is provided on the adhesive layer corresponding to the first conductive layer (04) or the second conductive layer (05) having the through hole, and the through hole is disposed opposite to the through hole.
9. The functional current collector according to claim 1, characterized in that, The porosity of the film is P, which is between 30% and 95%.
10. The functional fluid of claim 1 wherein, The pore size r of the upper pores of the film is 0.01 μm to 1 μm.