Cylindrical Li-Ion Cell Insulating Plate Opening Ratio
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Solution Overview
Problem
Conventional cylindrical lithium ion batteries face safety issues when abnormal pressure increases, causing the upper insulating plate to deform and close the valve hole, preventing immediate gas release and potentially leading to battery accidents.
Innovation Solution
A cylindrical lithium ion battery design featuring an insulating plate with a specific distribution of openings, including a first hole with a largest opening area and multiple second holes, optimized to ensure a total opening ratio between 20% and 50%, allowing for immediate gas release and preventing electrode group displacement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the upper insulating plate is made with conventional opening ratios, then the insulating plate maintains structural integrity, but the plate deforms and closes the valve hole when abnormal pressure increases
Solution Approach 1:
The patent changes the opening ratio parameter of the insulating plate from conventional values to a specific range of 20-50%, with the first hole accounting for 12-40% and second holes accounting for 0.3-10%. This parameter optimization allows the plate to maintain structural integrity while preventing deformation that would close the valve hole under abnormal pressure.
Solution Approach 2:
The insulating plate is segmented into multiple openings including a first hole with the largest area and multiple second holes with smaller areas. This segmentation distributes the structural stress across multiple openings rather than a single large opening, preventing deformation while maintaining sufficient gas release capability.
2Productivity
If the total opening ratio is increased to allow more gas release, then gas can be released more quickly, but the insulating plate becomes more prone to deformation
Solution Approach 1:
The patent optimizes the total opening ratio parameter to a specific range of 20-50%, balancing gas release capability with structural stability. This parameter range ensures sufficient gas release speed while preventing insulating plate deformation under abnormal pressure.
Solution Approach 2:
The opening is segmented into a first hole with the largest area for primary gas release and multiple second holes with smaller areas for additional gas release pathways. This segmentation provides multiple escape routes for gas, maintaining high gas release speed while distributing structural stress to prevent deformation.
3Productivity
If the first hole area is increased to improve gas release, then gas can escape more efficiently, but the insulating plate structure becomes weaker
Solution Approach 1:
The patent sets the first hole opening ratio within 12-40% of the total insulating plate area, optimizing gas release efficiency while maintaining structural strength. This parameter range ensures efficient gas escape through the largest opening without compromising the overall structural integrity of the insulating plate.
Solution Approach 2:
The gas release function is segmented between a first hole with the largest area for efficient primary release and multiple second holes with smaller areas for supplementary release. This segmentation achieves high gas release efficiency while distributing structural stress across multiple openings, preventing localized weakness.
Data Source
AI summary
A cylindrical lithium ion battery in which an electrode group formed by winding a positive electrode and a negative electrode is housed in a battery case is disclosed. A sealing plate seals an opening of the battery case. An insulating plate having a plurality of openings is provided on a side of the electrode group closer to the sealing plate. The plurality of openings include a first hole with a largest opening area, and a plurality of second holes with opening areas smaller than the opening area of the first hole. An opening ratio of the first hole is 12% or more and 40% or less; a sum of opening ratios of the second holes is 0.3% or more and 10% or less; and a total opening ratio of all the openings is 20% or more and 50% or less.