Battery Pack Spacer Elasticity for Swelling Control
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Solution Overview
Problem
Conventional battery packs with higher capacity secondary batteries face issues with swelling during charging and discharging cycles, where soft spacers fail to provide adequate support and hard spacers struggle to absorb expansion, leading to performance deterioration and increased resistance.
Innovation Solution
A battery pack design incorporating a spacer with an elastic part that has an elastic modulus between 1 MPa and 10 MPa and a constant load compression ratio of 35% to 70%, which allows stable loading and effective absorption of secondary battery expansion and contraction, thereby suppressing swelling and maintaining performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a soft spacer is used, then the secondary battery can be pressed suitably after charging and discharging cycle, but the spacer cannot absorb swelling of the secondary battery effectively
Solution Approach 1:
The patent applies parameter changes by precisely controlling the elastic modulus within 1-10 MPa and constant load compression ratio within 35-70% to achieve optimal balance between pressing capability and swelling absorption. This quantitative parameter optimization resolves the contradiction by finding the specific range where both requirements are satisfied simultaneously.
2Strength
If a hard spacer is used, then the secondary battery can be supported firmly, but the spacer cannot absorb swelling of the secondary battery effectively
Solution Approach 1:
The patent resolves this contradiction by changing the elastic modulus parameter to a specific range (1-10 MPa) that provides sufficient support firmness while maintaining swelling absorption capability. The controlled elastic modulus ensures the spacer is neither too soft nor too hard, achieving optimal performance for both support and adaptation to battery expansion.
3Strength
If the elastic modulus is increased to provide firm support, then the spacer can support the secondary battery firmly, but the spacer becomes too rigid to absorb swelling
Solution Approach 1:
The patent applies parameter changes by optimizing the elastic modulus within 1-10 MPa to achieve the right balance between firm support and adaptability to swelling. This controlled parameter range ensures the spacer maintains structural integrity while remaining flexible enough to accommodate battery expansion during charging cycles.
4Adaptability or versatility
If the elastic modulus is decreased to absorb swelling, then the spacer can absorb swelling effectively, but the spacer becomes too soft to provide adequate support
Solution Approach 1:
The patent resolves this contradiction by setting the elastic modulus within the specific range of 1-10 MPa, which prevents the spacer from being too soft while maintaining sufficient swelling absorption capability. This optimized parameter ensures both adequate support firmness and adaptability to battery expansion are achieved simultaneously.
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 proposed solution effectively stabilizes the secondary battery, suppressing swelling and maintaining performance by applying the appropriate load and absorption range, thus preventing excessive restriction and interelectrode distance increase, which can lead to Li precipitation.
Implementation Method 1
The spacer includes an elastic part, and the elastic part satisfies the following conditions: (1) an elastic modulus, which is obtained as an inclination of an approximation line A in a range of a compression ratio from 1 to 20% from a compression load-compression ratio curve
Data Source
AI summary
A battery pack disclosed herein includes a plurality of rectangular secondary batteries that are disposed along an arrangement direction, and a spacer that is disposed between the rectangular secondary batteries that are adjacent in the arrangement direction. The spacer includes an elastic part and the elastic part satisfies the following conditions: an elastic modulus in the arrangement direction is 1 MPa or more and 10 MPa or less; and a constant load compression ratio is 35% or more and 70% or less.