Fibrous Solid Electrolyte Layer for Crack-Resistant Batteries
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Solution Overview
Problem
Conventional batteries using alloying active materials face challenges in simultaneously achieving high discharge rate characteristics and charge-discharge efficiency due to volume expansion of the negative electrode active material, which can lead to cracking of the solid electrolyte layer and reduced energy density.
Innovation Solution
A battery design featuring a solid electrolyte layer with a higher content ratio of fibrous material in the second layer compared to the first layer, enhancing the layer's strength and resistance to cracking without increasing thickness, thereby maintaining discharge rate characteristics and charge-discharge efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the solid electrolyte layer thickness is increased to prevent cracking during volume expansion, then reliability improves, but discharge rate characteristics deteriorate
Solution Approach 1:
The patent applies local quality by creating a solid electrolyte layer with non-uniform fibrous material distribution. The second solid electrolyte layer (near the negative electrode) contains a higher content ratio of fibrous material (0.1-10 mass%) compared to the first solid electrolyte layer (0-5 mass%). This localized reinforcement provides crack resistance where volume expansion occurs during lithium-ion intercalation, while keeping other regions thinner to maintain good discharge rate characteristics.
2Quantity of substance
If alloying active material is used to increase battery capacity, then energy density improves, but charge-discharge efficiency deteriorates due to volume expansion
Solution Approach 1:
The patent applies beforehand cushioning by incorporating fibrous materials (such as polyolefin fibers) into the solid electrolyte layer prior to battery assembly. These fibrous materials are distributed throughout the solid electrolyte layer, with higher concentration in the second layer adjacent to the negative electrode. This pre-established fibrous network provides mechanical reinforcement that cushions against volume expansion stress during lithium-ion intercalation, preventing cracks before they occur and maintaining charge-discharge efficiency while enabling the use of high-capacity alloying active materials.
Data Source
AI summary
A battery includes a first electrode, a second electrode, and a solid electrolyte layer located between the first electrode and the second electrode and including a fibrous material, wherein the solid electrolyte layer includes a first solid electrolyte layer, and a second solid electrolyte layer located between the first solid electrolyte layer and the second electrode, and the content ratio of the fibrous material in the second solid electrolyte layer is higher than the content ratio of the fibrous material in the first solid electrolyte layer.