Electrode Assembly Short-Circuit Evaluation With Push and Guide Jigs
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Solution Overview
Problem
Existing methods for simulating micro short-circuiting in power storage devices face challenges such as difficulty in detecting single-layer short circuits due to voltage drops becoming smaller with increased capacity and the use of resin push jigs that may not transfer pushing load effectively, leading to potential penetration through multiple separator layers.
Innovation Solution
A method involving a conductive push jig with hardness equal to or greater than the metal piece, using a guide jig to stabilize the metal piece insertion, and detecting short circuits based on potential difference changes, reducing heat escape and ensuring accurate single-layer short-circuit detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a resin push jig is used to push the metal piece into the electrode assembly, then the procedure is easier to implement, but the pushing load is not transferred effectively to the metal piece, causing inconsistent penetration depth and potential multi-layer short circuits
Solution Approach 1:
The push jig material is changed from resin to metal with higher hardness. This parameter change ensures the push jig is harder than the metal piece, enabling effective load transfer and consistent penetration depth, while maintaining ease of operation through the standardized pushing procedure
2Quantity of substance
If the capacity of the power storage device is increased, then the energy storage capability is improved, but the voltage decrement caused by a short circuit becomes smaller, making detection difficult
Solution Approach 1:
The detection method is replaced from voltage-based detection to potential difference detection using a conductive push jig. The push jig acts as an electrode extension, directly measuring potential difference at the metal piece position, which remains effective regardless of device capacity
3Reliability
If a metal piece is pushed into the electrode assembly to simulate a micro short circuit, then the simulation of foreign object contamination is achieved, but the procedure becomes difficult to implement and requires skilled personnel
Solution Approach 1:
A conductive push jig with standardized dimensions and properties is introduced as an intermediary tool. This mediator enables consistent metal piece insertion without requiring disassembly or specialized skills, while maintaining reliable simulation of micro short circuits
Data Source
AI summary
A method of evaluating a power storage device comprises the following (a) to (d) in this order: (a) placing a metal piece on an outer surface of an electrode assembly; (b) pushing the metal piece into the electrode assembly; (c) detecting a short circuit based on a change in potential difference between an electrode inside the electrode assembly and the metal piece; and (d) stopping the pushing the metal piece. The (b) includes using a push jig and a guide jig. The guide jig is provided with a through hole. The push jig is inserted into the through hole. The metal piece has a ring shape. The metal piece is placed inside the through hole. A hardness of the push jig is equal to or more than a hardness of the metal piece.