Positive Electrode Plate Edge Trimming for Uniform Battery Thickness
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Solution Overview
Problem
The existing methods for preparing positive electrode plates result in uneven thickness, leading to large gaps between the electrode plates in batteries, which increases impedance and causes lithium precipitation and electrolyte depletion, reducing battery service life.
Innovation Solution
A method involving a current collector with a coating region and a non-coating region, where the non-coating region is cut to form tabs and an electrically insulating adhesive is applied to the edges of the positive-electrode active material, ensuring uniform thickness and preventing lithium precipitation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the positive-electrode active material in liquid form is coated on the current collector, then the coating process is simple and efficient, but the thickness of the edge of the positive-electrode active material becomes less than the thickness of other portions due to leveling phenomenon
Solution Approach 1:
The patent extracts and removes the problematic edge portions of the positive-electrode active material after coating. By cutting off the edges where the leveling phenomenon occurs, the remaining central portion maintains uniform thickness, eliminating the thickness variation caused by the coating process while preserving overall coating efficiency.
Solution Approach 2:
The patent segments the positive electrode plate into a central uniform-thickness region and edge regions. The edge regions are identified as having non-uniform thickness due to leveling, and these segments are removed through cutting, leaving only the uniform-thickness central region for battery assembly.
2Productivity
If the edge thickness of the positive electrode plate is small, then the coating process is faster, but the ion movement path between the edge of the positive electrode plate and the negative electrode plate becomes larger, increasing impedance
Solution Approach 1:
The patent removes the edge portions of the positive-electrode active material where thickness is reduced and impedance is increased. By cutting off these problematic edges, the remaining electrode plate maintains optimal thickness for ion transport, ensuring reliable ion movement paths while preserving the benefits of efficient coating processes.
3Reliability
If more electrolyte solution is provided between the edge of the positive electrode plate and the negative electrode plate, then ion deintercalation at the edge is ensured, but the electrolyte solution is continuously consumed and likely to dissociate after multiple cycles, resulting in electrolyte shortage
Solution Approach 1:
The patent removes the edge portions of the positive-electrode active material where excessive electrolyte consumption and dissociation occur. By eliminating these edges, the battery requires less electrolyte solution, and the remaining electrolyte is not continuously consumed or dissociated during cycling, preventing electrolyte shortage and maintaining reliable ion deintercalation efficiency.
Data Source
AI summary
A method for preparing a positive electrode plate, a positive electrode plate, and a battery including same. The method for preparing a positive electrode plate includes: providing a current collector, the current collector including a coating region and a non-coating region; coating a positive-electrode active material on the coating region of the current collector; cutting the non-coating region at intervals along a length direction of the non-coating region to form a tab between every two adjacent cutting positions, an edge of a region of the positive-electrode active material corresponding to the cutting position being cut off at each cutting; and coating an electrically insulating adhesive on an edge of the positive-electrode active material between every two adjacent cutting positions.