Electrode Assembly Separator Edge Sealing for Stability
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Solution Overview
Problem
Medium and large size battery modules face stability issues due to temperature gradients and separator shrinkage, leading to potential shorts and increased production costs, especially in stack/folding type electrode assemblies where edge parts of separators are not adequately treated.
Innovation Solution
An electrode assembly with improved stability is achieved by using a separator with a larger size than the electrodes, where the edge parts of the separators are attached to form a sealing part, either within a radical unit or across the cell stack, using a method that involves alternately stacking electrodes and separators and applying heat and pressure to secure them.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separator of the same size as conventional technology is used without edge treatment, then production cost is reduced, but stability decreases and internal shorts may occur due to separator shrinkage
Solution Approach 1:
The edge parts of the separator are attached to electrodes in advance during assembly, forming a sealed structure before the battery operates. This preliminary sealing action prevents separator shrinkage from causing internal shorts later, resolving the contradiction between using a smaller separator and maintaining stability.
Solution Approach 2:
The electrode acts as an intermediary element that the separator edge attaches to, creating a sealed structure. This intermediary attachment prevents direct contact between separator edges and electrolyte, eliminating the risk of internal shorts while allowing use of a smaller separator.
2Reliability
If a separator with larger size is used to prevent shrinkage, then stability is improved, but production cost increases
Solution Approach 1:
The invention changes the parameter of separator utilization by attaching its edge parts to electrodes, transforming it from a loose component to a sealed structure. This parameter change allows using a separator of the same size as conventional technology effectively, avoiding the need for a larger separator while maintaining stability.
3Ease of manufacture
If edge parts of separators are not attached, then manufacturing process is simpler, but internal shorts occur due to separator shrinkage
Solution Approach 1:
The edge parts of the separator are merged with the electrodes through attachment, forming an integrated sealed structure. This merging combines the separator's shrinkage resistance with the electrode's structural integrity, preventing internal shorts while adding minimal manufacturing complexity.
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
This approach reduces the risk of internal shorts, enhances stability, and decreases production costs by allowing the use of a smaller-sized separator, while maintaining the stability of the electrode assembly, even when using a separator of the same or smaller size compared to conventional technologies.
Implementation Method 1
applying heat and pressure to secure them
Implementation Method 2
applying heat and pressure to secure them
Data Source
AI summary
An electrode assembly includes a cell stack part having (a) a structure in which one kind of radical unit is repeatedly disposed, or (b) a structure in which at least two kinds of radical units are disposed in a predetermined order. The one kind of radical unit has a four-layered structure in which first electrode, first separator, second electrode and second separator are sequentially stacked or a repeating structure in which the four-layered structure is repeatedly stacked. Each of the at least two kinds of radical units are stacked by ones to form the four-layered structure or the repeating structure. The separator has a larger size than the electrode to expose an edge part of the separator to outside of the electrode and the separator. The edge parts of the separators included in one radical unit or in the cell stack part are attached to form a sealing part.