Separator With Partial Adhesive Layer For Battery Pressure Control
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Solution Overview
Problem
Non-aqueous electrolyte secondary cells face increased counterforce against expansion pressure due to repeated charge and discharge, leading to deteriorated performance and shorter life, with existing solutions failing to adequately control this pressure without compromising assembling stability.
Innovation Solution
A separator with a porous resin substrate and an adhesive layer, where the adhesive layer is partially disposed on the substrate, allowing for pressure alleviation by spreading into non-formation regions, thereby controlling the counterforce against expansion pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the assembling pressure of the assembled battery is decreased to reduce the counterforce against the expansion pressure of the electrode assembly, then the counterforce is reduced, but the assembling stability of the assembled battery deteriorates
Solution Approach 1:
The separator is divided into multiple layers: a porous resin substrate providing structural support and multiple adhesive layers partially disposed on the substrate. This segmentation allows different layers to perform different functions - the substrate maintains mechanical strength while the adhesive layers provide pressure distribution and bonding, resolving the contradiction between reducing counterforce and maintaining assembling stability
Solution Approach 2:
The adhesive layers are partially disposed on the substrate rather than covering the entire surface. This local quality approach creates regions with different properties: areas with adhesive layers provide bonding and pressure distribution, while areas without adhesive layers maintain porosity for electrolyte flow. This resolves the contradiction by providing stability where needed while allowing pressure relief in other areas
2Stability of the object's composition
If the assembling pressure is maintained high to ensure assembling stability, then the assembling stability is improved, but the counterforce against the expansion pressure increases causing deteriorated performance and shorter life
Solution Approach 1:
The adhesive layers act as intermediaries between the electrode assembly and the cell case. These adhesive layers distribute the assembling pressure uniformly across the separator surface, preventing localized high-pressure points that would increase counterforce. This allows the cell to maintain assembling stability while reducing the overall counterforce against expansion pressure, thereby extending cell life
Solution Approach 2:
The invention changes the physical parameters of the separator by adding adhesive layers with specific thickness and coverage ratios. This modifies how pressure is transmitted through the separator, transforming the pressure distribution pattern from concentrated to distributed. This parameter change allows the system to maintain stability at lower assembling pressures, reducing the counterforce and extending cell life
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 separator effectively suppresses the increase in counterforce against expansion pressure, improving assembling stability and extending the life of non-aqueous electrolyte secondary cells by maintaining uniform inter-electrode distance and alleviating pressure.
Implementation Method 1
an adhesive layer containing an adhesive resin, wherein the adhesive layer is partially disposed on one side of, or both of two sides of, the substrate in a thickness direction
Implementation Method 2
a sheet-like substrate made of a porous resin
Implementation Method 3
the adhesive layer is partially disposed on one side of, or both of two sides of, the substrate in a thickness direction thereof
Data Source
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AI summary
The separator disclosed herein includes a substrate and an adhesive layer. The adhesive layer is partially provided on one side of, or both of two sides of, the substrate. Where an initial thickness of the separator is T0, a thickness of the separator when the separator is impregnated with an electrolyte solution and supplied with a pressure of 1 MPa is T1, a thickness of the separator when, after this, the separator is supplied with a pressure of 2 MPa for 1 hour, and the pressure is decreased to 0.5 MPa, is T2, and a thickness of the separator when, after this, the separator is supplied with a pressure of 4 MPa for 48 hours, is T4, the separator satisfies inequalities (1) through (3): (1) 1 ≤ T1/T0 ≤ 1.1; (2) 0.92 ≤ T2/T1 ≤ 1; and (3) 0.6 ≤ T4/T1 ≤ 0.8.