Battery Separator with Elastic Layer for Expansion Absorption
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Solution Overview
Problem
The existing power supply devices with stacked battery cells face issues due to the inability of traditional separators to absorb the expansion of battery cells over time, leading to increased stress on end plates and binding bars, which results in material and cost inefficiencies and potential malfunction.
Innovation Solution
Incorporating a separator with a heat insulating layer, an elastic layer that absorbs expansion, and a stopper with higher rigidity to limit compression thickness, which reduces the deterioration of the elastic layer and maintains effective heat insulation characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a hard plastic separator is used to insulate battery cells, then insulation performance is improved, but the separator cannot absorb battery cell expansion causing increased stress on end plates and binding bars
Solution Approach 1:
The separator is constructed as a composite material combining a heat insulating layer (made of materials like silica aerogel, polyethylene, or polypropylene) and an elastic layer (made of rubber-like elastic bodies such as silicone rubber, fluororubber, or thermoplastic elastomers). This composite structure provides both insulation performance and expansion absorption capability, resolving the contradiction between maintaining insulation and preventing excessive stress on structural components.
2Reliability
If an elastic layer is used to absorb battery cell expansion, then expansion absorption is improved, but the elastic layer deteriorates under repeated strong pressure
Solution Approach 1:
The separator structure assigns different functional qualities to different layers: the heat insulating layer provides thermal insulation and structural support, while the elastic layer provides expansion absorption. This local differentiation of functions allows each layer to optimize its performance without compromising the other, enabling long-term expansion absorption without deterioration.
Solution Approach 2:
The elastic layer acts as a cushioning element that anticipates and absorbs battery cell expansion before it can transmit stress to the end plates and binding bars. By providing this preliminary cushioning effect, the system prevents the transmission of damaging forces that would otherwise cause deterioration of the elastic layer and structural components over time.
3Stability of the object's composition
If strong compression force is applied to fix battery cells, then positional stability is improved, but material cost and weight of end plates and binding bars increase
Solution Approach 1:
The introduction of the elastic layer changes the mechanical parameter profile of the separator system. Instead of requiring rigid, heavy end plates and binding bars to maintain positional stability, the elastic layer provides a compliant interface that maintains cell positioning through elastic deformation rather than rigid constraint. This parameter change allows for lighter structural components while maintaining stability.
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 solution effectively absorbs battery cell expansion over a long period, reducing relative displacement and preventing connection failures, while maintaining excellent heat insulation and reducing material costs by using a hybrid material like silica aerogel for enhanced thermal resistance.
Implementation Method 1
an elastic layer that absorbs expansion of battery cells
Implementation Method 2
heat insulating layer
Data Source
AI summary
End plates are disposed on respective end faces of a battery block formed by stacking a plurality of battery cells in a thickness with separator interposed between corresponding battery cells, and the end plates paired are coupled by a binding bar to fix the battery block in a compressed state. Separator includes heat insulating layer, elastic layer that absorbs expansion of battery cells, and stopper that limits a compression thickness of elastic layer, and stopper has higher rigidity than elastic layer.