Multi-Cavity Pouch Cell Layout for High-Temperature Expansion Buffering
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Solution Overview
Problem
Same pouch series/parallel connected batteries are prone to expansion under high-temperature conditions, leading to reduced safety performance.
Innovation Solution
The electrochemical device features a housing with a first and second electrode assembly and N separators, where the separators define N+1 accommodating cavities. The second accommodating cavity is larger than the first, with a volume difference of 0.5% to 5%, to buffer expansion and inhibit excessive internal pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple battery cells are connected in series to improve output power, then the output power is improved, but the energy density of the battery pack decreases
Solution Approach 1:
The patent combines multiple electrode assemblies (first electrode assembly and second electrode assembly) into a single pouch housing to form an integrated battery pack. This merging approach allows the battery pack to achieve the desired output power through series connection while maintaining higher energy density by eliminating redundant housing structures and separators that would otherwise be required for separate battery cells.
2Temperature
If the first accommodating cavity expands under high-temperature conditions, then the internal pressure increases, but the second accommodating cavity may experience excessive expansion and packaging failure
Solution Approach 1:
The patent designs the second accommodating cavity with a larger volume than the first accommodating cavity, creating a buffer capacity beforehand. This prior cushioning design allows the second cavity to absorb expansion pressure from the first cavity when both are subjected to high-temperature conditions, preventing excessive expansion and packaging failure, thereby improving the safety performance of the battery pack.
3Volume of stationary object
If the volume of the first accommodating cavity is too small, then the internal pressure becomes too large, but local excessive expansion and packaging failure occur
Solution Approach 1:
The patent optimizes the volume parameters of the accommodating cavities by establishing a specific volume ratio relationship between the first and second accommodating cavities. This parameter change ensures that the first accommodating cavity has sufficient volume to prevent excessive internal pressure under high-temperature conditions, while the second accommodating cavity maintains a larger volume to buffer expansion, thereby preventing local excessive expansion and packaging failure.
Data Source
AI summary
An electrochemical device, including a housing and N separators. The N separators and the housing together define N+1 accommodating cavities arranged along a first direction. The N+1 accommodating cavities include a first accommodating cavity and a second accommodating cavity adjacent to each other, wherein N≥2. A first electrode assembly is accommodated in the first accommodating cavity, and a second electrode assembly is accommodated in the second accommodating cavity. The second electrode assembly is far from a reference surface relative to the first electrode assembly. The reference surface is a plane that passes through the 10 center of the electrochemical device along the first direction and is perpendicular to the first direction. The volume V1 of the first accommodating cavity and the volume V2 of the second accommodating cavity satisfy 0.5%≤(V2−V1)/V1≤5%, so that the safety performance of the electrochemical device is improved.