Positive Electrode Thin Portions to Prevent Battery Plate Deformation
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Solution Overview
Problem
The plastic deformation of electrode plates in secondary batteries, such as lithium-ion batteries, during charge and discharge leads to potential short circuits, necessitating complex insulation measures that increase cost and reduce capacity.
Innovation Solution
A positive electrode design with specific thin portions on its mixture layer, positioned on the winding core side of the electrode assembly, to absorb expansion and relax stress, thereby inhibiting plastic deformation and simplifying insulation requirements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If insulation measures are taken to prevent short circuit caused by plastic deformation, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent applies preliminary action by forming thin portions in the positive electrode mixture layer before battery assembly. These thin portions are pre-designed to accommodate expansion of the negative electrode during charging, thereby preventing plastic deformation of the electrode plate and eliminating the need for complex insulation measures later.
Solution Approach 2:
The patent applies local quality by creating thin portions at specific locations in the positive electrode mixture layer rather than uniformly thinning the entire layer. The thin portions are positioned to correspond to areas where negative electrode expansion occurs, providing localized stress relief where needed most while maintaining the integrity of other electrode regions.
2Reliability
If insulation measures are added to prevent short circuit, then reliability is improved, but manufacturing cost increases
Solution Approach 1:
The thin portions are formed during the electrode manufacturing process itself, integrating the deformation prevention function into the base manufacturing flow. This eliminates the need for separate insulation components and assembly steps, thereby reducing manufacturing cost while maintaining reliability.
3Reliability
If insulation measures are implemented, then short circuit prevention is improved, but battery capacity decreases
Solution Approach 1:
By localizing the thin portions only in areas where negative electrode expansion occurs, the patent preserves the full thickness and active material content of the positive electrode in other regions. This maintains maximum battery capacity while providing targeted stress relief to prevent short circuits.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The design effectively inhibits electrode plate deformation, allowing for increased capacity and reduced insulation complexity while maintaining battery performance.
Implementation Method 1
the second region includes: a first thin portion provided from one end in a length direction of the positive electrode mixture layer with a length of greater than or equal to 1% and less than or equal to 3% of a length of the positive electrode mixture layer; and a second thin portion provided from one end in the length direction of the positive electrode mixture layer with a predetermined space from the first thin portion within a range of less than or equal to 40% of the length of the positive electrode mixture layer
Data Source
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AI summary
A positive electrode (11) includes: a long positive electrode core (30); and positive electrode mixture layers (31) disposed on both surfaces of the positive electrode core (30). The positive electrode mixture layers (31) include a first region (32) and a thin portion (33) that is a second region thinner than the first region (32). The thickness of the thin portion (33) is 20-90% of the average thickness of the first region (32). The thin portion (33) includes a first thin portion (33) and a second thin portion (34) provided at a predetermined distance from the first thin portion (33).