Bipolar Battery Separator Thickness Optimization
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Solution Overview
Problem
Bipolar-type lithium ion secondary batteries face issues with heat accumulation and vibration-induced layer dissociation due to excessive thickness ratios of positive and negative electrode active material layers, leading to decreased output and service life.
Innovation Solution
A bipolar battery design where the separator thickness is between 0.68 and 1.0 times that of the positive and negative electrode active material layers, enhancing heat radiation and vibration isolation characteristics by optimizing the thickness ratios and using materials like polypropylene or polyolefin for the separator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the thickness ratios of positive and negative electrode active material layers are increased to maximize capacity and output, then the energy density and output density are improved, but heat accumulates in the battery interior causing deterioration of electrolyte and reduced service life
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness ratios of battery components. Specifically, it sets the separator thickness to 0.05-0.15mm, positive electrode active material layer thickness to 0.3-0.7mm, and negative electrode active material layer thickness to 0.3-0.7mm, creating a balanced structure that improves heat radiation while maintaining output density.
Solution Approach 2:
The patent applies local quality by giving different thickness specifications to different parts of the battery structure. The separator is made thinner (0.05-0.15mm) compared to the electrode layers (0.3-0.7mm), creating localized optimization where each component's thickness is tailored to its specific function - the thin separator facilitates heat radiation while the thicker electrode layers maintain capacity.
2Quantity of substance
If the thickness ratios of positive and negative electrode active material layers are increased to maximize capacity, then the energy density is improved, but the battery becomes prone to vibration-induced layer dissociation
Solution Approach 1:
The patent applies parameter changes by optimizing the thickness ratios of battery components. Specifically, it sets the separator thickness to 0.05-0.15mm, positive electrode active material layer thickness to 0.3-0.7mm, and negative electrode active material layer thickness to 0.3-0.7mm, creating a balanced structure that improves vibration resistance while maintaining energy density.
Solution Approach 2:
The patent applies local quality by giving different thickness specifications to different parts of the battery structure. The separator is made thinner (0.05-0.15mm) compared to the electrode layers (0.3-0.7mm), creating localized optimization where each component's thickness is tailored to its specific function - the thin separator reduces vibration susceptibility while the thicker electrode layers maintain capacity.
Data Source
AI summary
A bipolar battery includes: a bipolar electrode composed, by forming a positive electrode active material layer 12 an one surface of a current collector and forming a negative electrode active material layer 13 on the other surface; and a separator 14 composed to be stacked alternately with the bipolar electrode, wherein, in a single cell layer 15 composed by including the positive electrode active material layer 12, the separator 14 and the negative electrode active material layer 13, which are adjacent to one another, a thickness of the separator 14 is 0.68 times or more to less than 1.0 times a thickness of the positive electrode active material layer 12, and is 0.68 times or more to less than 1.0 times a thickness of the negative electrode active material layer 13.