电极组件及电池
By setting a counter-layer on the negative electrode, the diffusion and mass transfer rate of lithium ions are optimized, solving the problem of lithium plating in lithium-ion batteries and improving the safety and lifespan of the batteries.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- EVE ENERGY CO LTD
- Filing Date
- 2025-07-01
- Publication Date
- 2026-07-17
AI Technical Summary
In lithium-ion batteries, when a central tab is placed on the positive electrode, lithium plating is prone to occur at the position on the negative electrode opposite to the central tab of the positive electrode, which affects the battery's lifespan and safety.
A counter-position layer is placed on the negative electrode plate at a position opposite to the positive electrode tab groove. By increasing the solid-phase diffusion rate and liquid-phase mass transfer rate of lithium ions in the counter-position layer, lithium deposition at that position is reduced. The counter-position layer consists of multiple sublayers, and the diffusion rate and mass transfer rate of each sublayer are designed according to a gradient to optimize the lithium ion insertion process.
It effectively reduces the risk of lithium ion deposition on the negative electrode, improves the safety and stability of the electrode assembly, and extends the battery life.
Smart Images
Figure CN224519875U_ABST
Abstract
Claims
1. An electrode assembly, characterized by, The electrode assembly includes: A positive electrode sheet (10) includes a positive current collector (11) and a positive active material layer (12) disposed on the surface of the positive current collector (11), wherein a positive electrode tab groove (121) is disposed on the positive active material layer (12); Positive electrode tab (13), one end of which is disposed in the positive electrode tab groove (121) and electrically connected to the positive current collector (11); A diaphragm (20) is disposed on the side of the positive electrode active material layer (12) away from the positive electrode current collector (11); A negative electrode sheet (30) is disposed on the side of the separator (20) away from the positive electrode active material layer (12). The negative electrode sheet (30) includes a negative electrode current collector (31). The negative electrode current collector (31) has a first region and a second region on the side facing the separator (20). The orthogonal projection of the second region on the positive electrode sheet (10) is located within the outline of the positive electrode tab groove (121). The first region and the second region are respectively coated with negative electrode active material materials of different properties to form a negative electrode active material layer (321) and a counter layer (322), respectively. Wherein, the minimum solid-phase diffusion rate of lithium ions in the para-position layer (322) is greater than the solid-phase diffusion rate of lithium ions in the negative electrode active material layer (321); and / or, the minimum liquid-phase mass transfer rate of lithium ions in the para-position layer (322) is greater than the liquid-phase mass transfer rate of lithium ions in the negative electrode active material layer (321).
2. The electrode assembly of claim 1, wherein, The para-position layer (322) includes a plurality of adjacent sub-layers, each of which is formed by coating with a negative electrode active material, and the solid-phase diffusion rate of lithium ions in two adjacent sub-layers is different. And / or the liquid phase mass transfer rates of lithium ions differ in two adjacent sublayers.
3. The electrode assembly of claim 2, wherein, The multiple sub-layers are arranged sequentially from the inside to the outside of the layer described in claim PN313249HZYWLN.
4. The electrode assembly according to claim 3, characterized in that, Along the direction from the innermost sublayer to the outermost sublayer, the solid-phase diffusion rate of lithium ions in the multiple sublayers gradually increases, and the solid-phase diffusion rate of lithium ions in the innermost sublayer is greater than the solid-phase diffusion rate of lithium ions in the negative electrode active material layer (321); and / or, Along the direction from the innermost sublayer to the outermost sublayer, the liquid phase mass transfer rate of lithium ions in the multiple sublayers gradually increases, and the liquid phase mass transfer rate of lithium ions in the innermost sublayer is greater than the liquid phase mass transfer rate of lithium ions in the negative electrode active material layer (321).
5. The electrode assembly of claim 4, wherein, Along the direction from the innermost sublayer to the outermost sublayer: The multiplier of the sublayers gradually increases, with the innermost sublayer having a higher multiplier than the negative electrode active material layer (321); and / or, The median particle size of the sublayers gradually decreases, and the median particle size of the innermost sublayer is smaller than the median particle size of the negative electrode active material layer (321); and / or, The content of the conductive agent in the sublayer gradually increases, and the content of the conductive agent in the innermost sublayer is higher than the content of the conductive agent in the negative electrode active material layer (321); and / or, The porosity of the sublayer gradually decreases, and the porosity of the innermost sublayer is less than that of the negative electrode active material layer (321).
6. The electrode assembly of claim 5, wherein, The alignment layer (322) includes a first sublayer (3221) and a second sublayer (3222). The first sublayer (3221) has a rectangular outline, and the second sublayer (3222) is arranged in a ring around the outer periphery of the first sublayer (3221). The multiplier of the first sublayer (3221) is C1, the multiplier of the second sublayer (3222) is C2, 1C≤C1≤5C, 5C≤C2≤10C; and / or, The median particle size of the first sublayer (3221) is D501, and the median particle size of the second sublayer (3222) is D502, where 8 μm ≤ D501 ≤ 15 μm, and 2 μm ≤ D502 ≤ 10 μm; and / or, The conductive agent content of the first sublayer (3221) is A1, and the conductive agent content of the second sublayer (3222) is A2, with 0.5% ≤ A1 ≤ 2% and 1% ≤ A2 ≤ 4%; and / or, The porosity of the first sublayer (3221) is B1, and the porosity of the second sublayer (3222) is B2, where 5≤B1≤10 and 1.5≤B2≤5.
7. The electrode assembly of claim 3, wherein The multiple sublayers cover the same area on the surface of the negative electrode current collector (31).
8. The electrode assembly of claim 3, wherein, The thickness of each of the sub-layers is the same as the thickness of the negative electrode active material layer (321).
9. The electrode assembly of claim 2, wherein, Multiple sub-layers are stacked sequentially along the thickness direction of the negative electrode current collector (31).
10. The electrode assembly according to claim 9, characterized in that, Along the direction from the negative electrode current collector (31) to the separator (20), the solid-phase diffusion rate of lithium ions in the multiple sub-layers gradually increases, and the solid-phase diffusion rate of lithium ions in the bottommost sub-layer is greater than the solid-phase diffusion rate of lithium ions in the negative electrode active material layer (321); and / or, Along the direction from the negative electrode current collector (31) to the separator (20), the liquid phase mass transfer rate of lithium ions in the multiple sub-layers gradually increases, and the solid phase diffusion rate of lithium ions in the bottommost sub-layer is greater than the solid phase diffusion rate of lithium ions in the negative electrode active material layer (321).
11. The electrode assembly of claim 10, wherein, Along the direction from the negative electrode current collector (31) to the diaphragm (20): The multiplier of the sublayers gradually increases, with the multiplier of the bottommost sublayer being higher than that of the negative electrode active material layer (321); and / or, The median particle size of the sublayers gradually decreases, and the median particle size of the bottommost sublayer is smaller than that of the negative electrode active material layer (321); and / or, the content of the conductive agent in the sublayers gradually increases, and the content of the conductive agent in the bottommost sublayer is higher than that of the conductive agent in the negative electrode active material layer (321); and / or, The porosity of the sublayers gradually decreases, and the porosity of the bottommost sublayer is less than that of the negative electrode active material layer (321).
12. The electrode assembly of claim 11, wherein, The counter-layer (322) includes a third sub-layer (3223) and a fourth sub-layer (3224), wherein the third sub-layer (3223) is coated on the negative electrode current collector (31), and the fourth sub-layer (3224) is coated on the third sub-layer (3223); The multiplier of the third sublayer (3223) is C3, the multiplier of the fourth sublayer (3224) is C4, 1C≤C3≤5C, 5C≤C4≤10C; and / or, The median particle size of the third sublayer (3223) is D503, and the median particle size of the fourth sublayer (3224) is D504, where 8µm ≤ D503 ≤ 15µm, and 2µm ≤ D504 ≤ 10µm; and / or, The conductive agent content of the third sublayer (3223) is A3, and the conductive agent content of the fourth sublayer (3224) is A4, where 0.5% ≤ A3 ≤ 2%, and 1% ≤ A4 ≤ 4%; and / or, The porosity of the third sublayer (3223) is B3, and the porosity of the fourth sublayer (3224) is B4, 5≤B3≤10, 1.5≤B4≤5.
13. The electrode assembly of claim 9, wherein, All of the sub-layers have the same thickness.
14. The electrode assembly according to any one of claims 1 to 13, characterized in that, The negative electrode active material layer (321) and the para layer (322) have the same thickness.
15. The electrode assembly of any one of claims 1 to 13, wherein, The alignment layer (322) covers an area S1 of the negative electrode current collector (31), and an area S2 of the positive electrode tab groove (121) in a direction parallel to the positive electrode current collector (11), 16. A battery, characterized by Includes the electrode assembly as described in any one of claims 1 to 15.