Battery Electrode Coating Thickness Control at Insulation Boundaries
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Solution Overview
Problem
The boundary position of the active material layer and insulation layer blur during the drying process, leading to mutual infiltration and mixing, affecting the size of the electrode plate and potentially causing safety issues such as internal short circuits and reduced battery capacity.
Innovation Solution
Control the thickness of the active material layer to be 200-400 μm and the ratio of the insulation layer to the active material layer to be 0.5-0.7, adjusting the coating weight and compaction density to minimize the interaction zone at their junction.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the active material layer and insulation layer are coated synchronously on the current collector, then the coating process is simplified and production efficiency is improved, but the boundary position between the two layers blurs during drying due to mutual infiltration and mixing
Solution Approach 1:
The patent controls the thickness of the insulation layer to be 0.5-0.7 times the thickness of the active material layer. By optimizing this thickness parameter ratio, the patent reduces the relative infiltration depth of active material into the insulation layer, thereby maintaining clearer boundary positions while still allowing synchronous coating for high productivity.
2Quantity of substance
If the thickness of the active material layer is increased to improve battery capacity, then the energy storage capacity increases, but the interaction zone size at the junction with the insulation layer increases, affecting electrode plate size control
Solution Approach 1:
The patent specifies that the active material layer thickness should be controlled at 200-400 μm and the insulation layer thickness should be 0.5-0.7 times the active material layer thickness. This parameter optimization allows sufficient active material for high capacity while limiting the absolute size of the interaction zone through proportional insulation layer thickness.
Solution Approach 2:
The insulation layer acts as an intermediary barrier between the active material layer and the current collector edge. By positioning it at the optimized thickness ratio (0.5-0.7), it effectively contains the interaction zone within acceptable limits while allowing the active material layer to achieve the required thickness for high capacity.
3Reliability
If the insulation layer thickness is increased to prevent burrs and improve safety, then the safety performance improves, but the interaction zone size increases and the electrode plate size control is affected
Solution Approach 1:
The patent determines that the optimal insulation layer thickness is 0.5-0.7 times the active material layer thickness. This parameter optimization provides sufficient insulation thickness for safety and burr prevention, while simultaneously limiting the interaction zone size to maintain precise electrode plate dimensions.
Data Source
AI summary
A secondary battery includes a positive electrode plate. The positive electrode plate includes a current collector, a tab protruding from the current collector, and an insulation layer disposed on at least one surface of the current collector. The insulation layer is disposed along a side edge of the current collector and abutted against the active material layer; the tab protrudes from the side edge of the current collector; A ratio of a thickness of the insulation layer to a thickness of the active material layer is 0.5-0.7, and the thickness of the active material layer is 200-400 μm.