Battery cell and battery
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Solution Overview
Problem
Battery cells experience internal short circuits due to electrolyte leakage and separator contraction when the encapsulating film deforms, leading to poor drop performance.
Innovation Solution
A battery cell design featuring multiple adhesive layers and films with varying adhesive forces to securely attach the electrode assembly, reducing the risk of unbalanced forces and short circuits by ensuring a stronger connection between the outermost electrode plate and the separator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the encapsulating film is secured to the electrode assembly using adhesive, then the seal integrity is improved, but the adhesive may fail under drop impact causing separator contraction and internal short circuit
Solution Approach 1:
The adhesive system is segmented into multiple layers with different functions: a first adhesive layer for basic bonding and a second adhesive layer with higher adhesive force for critical separator attachment. This segmentation allows each layer to specialize in specific protective functions, preventing separator contraction and internal short circuits during drop impacts while maintaining seal integrity.
Solution Approach 2:
Different regions of the adhesive system have different adhesive forces tailored to local requirements. The second adhesive layer applied to the outermost separator has higher adhesive force than the first adhesive layer, creating local quality enhancement at critical areas. This ensures that the separator remains firmly attached during drop impacts, preventing the harmful effect of internal short circuits.
2Device complexity
If a single adhesive layer is used to attach the electrode assembly, then the device complexity is reduced, but the drop performance deteriorates due to unbalanced forces causing electrode plate tearing
Solution Approach 1:
The adhesive structure is divided into multiple layers with the first adhesive layer providing basic attachment and the second adhesive layer providing enhanced bonding at critical locations. This segmentation creates a more complex but reliable structure that prevents electrode plate tearing during drops by distributing forces more evenly across the assembly.
Solution Approach 2:
The adhesive system uses composite material principles by combining different adhesive layers with varying adhesive forces. The first adhesive layer and second adhesive layer work together as a composite system, where each layer contributes different mechanical properties to achieve optimal drop performance while managing the complexity through systematic design.
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 enhances the drop performance of battery cells by preventing electrode plate tearing and internal short circuits, thereby improving safety and stability during drops.
Implementation Method 1
a first adhesive force between the first adhesive film and the first surface is greater than a second adhesive force between the second adhesive film and the first surface
Data Source
AI summary
An electrode assembly, where an outer surface of the electrode assembly includes a first surface, a first end face, a second surface, and a second end face that are connected in sequence, the first surface is provided opposite to the second surface, and the first end face is provided opposite to the second end face; a first adhesive layer, where the first adhesive layer is adhered to the first end face and extends from the first end face to the first surface and the second surface separately, and a side of the first surface provided with the first adhesive layer is defined as a top side; and a second adhesive layer, where the second adhesive layer is adhered to the second end face and extends from the second end face to the first surface and the second surface separately.