Electrode Assembly Insulation-Enhancing Part for Separator Shrinkage
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Solution Overview
Problem
Lithium secondary batteries are prone to short-circuiting and thermal runaway due to heat shrinkage of the separator, leading to safety risks, especially during high-temperature exposure or external impacts.
Innovation Solution
An electrode assembly with an insulation-enhancing part, such as an insulating coating layer or adhesive tape, is formed on the outer periphery of the separator adjacent to electrode tabs, preventing heat shrinkage and potential contact between cathode and anode plates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separator with standard structure is used, then the battery structure is simple and manufacturing is easy, but the separator shrinks under heat leading to short circuits and safety issues
Solution Approach 1:
The separator is divided into two functional zones: a base separator layer providing standard separation, and an insulation-enhancing part formed on the edge portions adjacent to electrode tabs. This segmentation allows the edge regions to resist heat shrinkage while the central region maintains normal separator function, resolving the contradiction between reliability and structural simplicity.
Solution Approach 2:
The insulation-enhancing part is applied locally only at the edge portions of the separator where heat shrinkage most critically affects safety near electrode tabs. This local enhancement provides targeted thermal resistance where needed most, rather than uniformly increasing complexity across the entire separator structure.
2Reliability
If the separator outer periphery is increased to prevent short circuits, then safety is improved, but the battery volume and material usage increase
Solution Approach 1:
The separator structure is segmented into a standard central region and extended edge portions with insulation enhancement. This allows the insulation function to be concentrated at the critical edge regions where short circuit risk is highest, rather than uniformly increasing the entire separator size, thus preventing short circuits without excessive volume increase.
Solution Approach 2:
The insulation-enhancing part is localized to the edge portions of the separator adjacent to electrode tabs, providing enhanced thermal resistance only where heat shrinkage most critically affects safety. This local enhancement achieves improved short circuit prevention without the need to uniformly increase the entire separator dimensions.
3Reliability
If insulation-enhancing part is formed on separator edge portions, then heat shrinkage is suppressed and safety is enhanced, but manufacturing complexity increases
Solution Approach 1:
The insulation-enhancing part is formed locally on the edge portions of the separator where it is most needed for safety, rather than applying it uniformly across the entire separator. This localized approach minimizes the additional manufacturing complexity while maximizing the safety benefit at the critical edge regions adjacent to electrode tabs.
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 insulation-enhancing part effectively suppresses separator shrinkage, preventing short circuits and enhancing battery safety by maintaining insulation between electrode plates even under abnormal operating conditions.
Implementation Method 1
an insulation-enhancing part for suppressing heat shrinkage of a separator formed in the outer peripheries
Data Source
AI summary
An electrode assembly is provided. The electrode assembly has a plurality of electrode plates having one or both sides of each of the electrode plates that are coated with an electrode active material and are stacked with a separator interposed between the respective electrode plates. The separator includes a surplus outer periphery of a size greater than the outer periphery of an electrode plate, an electrode tab which extends from the outer periphery of the electrode plate and protrudes outwardly beyond the outer periphery of the separator is formed on each electrode plate, and at least some of the separators forming the electrode assembly have an insulation-enhancing part for suppressing heat shrinkage of a separator formed in the surplus outer peripheries thereof which are adjacent to the respective electrode tabs.