Zero-Point Adjustment for Battery Penetration Testing
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Solution Overview
Problem
Existing penetration test apparatuses struggle to accurately set the zero point for nail insertion depth in pouch-shaped battery cells, leading to inconsistent and unreliable test results due to variations in contact pressure and uneven surfaces, which can affect the safety evaluation of lithium secondary batteries.
Innovation Solution
A penetration test apparatus with a zero-point adjustment unit that protrudes from the upper surface pressing plate, allowing for precise setting of the zero point by measuring resistance when the nail contacts the unit, ensuring consistent and reliable penetration tests by maintaining tight contact between the battery case and electrode assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a zero-point auxiliary jig is used to set the zero point position, then the zero point can be determined, but the measurement precision is insufficient due to the cylindrical shape not matching the flat surface of pouch-shaped batteries
Solution Approach 1:
The zero-point adjustment apparatus uses a flat pressing surface that locally matches the flat contact area of pouch-shaped batteries, rather than using a cylindrical jig. This local quality match ensures precise zero point positioning on the specific contact region where the battery surface is flat, resolving the contradiction between measurement precision and manufacturing precision.
2Measurement precision
If the battery is not pressed with sufficient force, then the battery structure remains flexible, but the contact between battery case and electrode assembly is insufficient causing depth measurement errors
Solution Approach 1:
The apparatus applies preliminary pressing force through the flat zero-point adjustment apparatus before nail insertion to ensure the battery case and electrode assembly are in tight contact. This preliminary action stabilizes the battery structure, enabling accurate depth measurement without requiring excessive pressing force during the actual penetration test.
3Ease of operation
If a through-hole is formed in the pressing plate for nail insertion, then the penetration test can be performed, but the auxiliary pressing part blocks the through-hole making insertion difficult
Solution Approach 1:
The design extracts the auxiliary pressing function from a separate blocking component and integrates it into the pressing plate structure itself. The pressing plate contains both the through-hole for nail insertion and the auxiliary pressing surface in a unified structure, eliminating the blocking problem while maintaining the necessary pressing function.
4Reliability
If the zero point is set using visual estimation, then the process is simple, but the reliability of the penetration test is low due to inconsistent zero point positioning
Solution Approach 1:
The invention replaces visual estimation with a mechanical reference system. The flat zero-point adjustment apparatus provides a physical reference surface at a known distance from the pressing plate, allowing the zero point to be determined by mechanical contact rather than visual estimation. This substitution significantly improves reliability while adding minimal complexity to the system.
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 apparatus ensures accurate and reliable penetration tests by setting the zero point based on resistance measurement, thereby improving the consistency and reliability of safety evaluations for pouch-shaped battery cells.
Implementation Method 1
measuring resistance when the nail contacts the unit
Data Source
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AI summary
Disclosed are a penetration test apparatus including an upper surface pressing plate configured to press an upper surface of a battery cell, a lower surface pressing plate configured to press a lower surface of the battery cell, a through-hole in the upper surface pressing plate, a nail configured to penetrate the battery cell through the through-hole, and a zero-point adjustment unit protruding outward from an outer periphery of a side of the upper surface pressing plate and a penetration test method using the same, wherein it is possible to accurately set the zero point, which is a reference point for the position where the nail is inserted.