Current Interrupting Mechanism for Vibration-Resistant Battery Safety
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Solution Overview
Problem
Existing current interrupting mechanisms in non-aqueous electrolyte secondary batteries are susceptible to malfunction due to vibration or impact, which is a concern for applications requiring high safety and impact resistance, such as electric vehicles.
Innovation Solution
A non-aqueous electrolyte secondary battery design featuring a diaphragm that deforms to break a fragile portion of the current collecting tab, interrupting current flow when internal pressure increases, combined with a current collecting tab holder and external electrode terminal configuration that enhances impact and vibration resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a current interrupting mechanism is implemented to improve battery safety, then reliability is improved, but the mechanism becomes susceptible to malfunction due to vibration or impact
Solution Approach 1:
The current collecting tab is divided into a fragile portion and a current collector connecting portion. The fragile portion is designed to break under excessive pressure to interrupt current flow, while the current collector connecting portion remains intact to maintain electrical connection. This segmentation allows the safety mechanism to function independently without affecting the overall structural integrity.
Solution Approach 2:
The fragile portion is pre-designed with reduced thickness to create a predetermined weak point that will break at a specific pressure threshold. This preliminary preparation ensures that when excessive internal pressure occurs, the current interrupting mechanism activates reliably without requiring complex sensing or control systems.
2Ease of manufacture
If the current collecting tab is made thinner to facilitate fragile portion breakage, then ease of manufacture is improved, but impact resistance deteriorates
Solution Approach 1:
The current collecting tab has non-uniform thickness distribution: the fragile portion is made thin (0.03-0.08mm) to facilitate breakage at the predetermined location, while the current collector connecting portion maintains sufficient thickness (0.1-0.3mm) to provide impact resistance and structural strength. This local quality differentiation resolves the contradiction between ease of manufacture and impact resistance.
3Manufacturing precision
If a throughhole is formed in the current collecting tab to create the fragile portion, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
Instead of forming a throughhole that would require complex drilling or punching operations, the invention extracts material only from one surface to create a thin fragile portion. This approach achieves precise positioning of the break point while maintaining simple single-sided processing, reducing device complexity while preserving manufacturing precision.
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 solution effectively interrupts current flow upon increased internal pressure while maintaining high impact and vibration resistance, preventing safety mechanism malfunction and enhancing battery safety for high-output applications.
Implementation Method 1
a diaphragm (6) disposed inside the sealing plate (3) and outside the current collecting tab (9) in the battery, the diaphragm (6) being electrically connected to the external electrode terminal (1) and deforming toward the outside of the battery when the battery internal pressure increases
Data Source
AI summary
A non-aqueous electrolyte secondary battery has a current interrupting mechanism with excellent impact and vibration resistance. The mechanism includes a fragile portion which breaks when the diaphragm deforms and rises upward, thereby interrupting current flow thereto; and an insulating current collecting tab holder into which a part of a current collecting tab is inserted. The tab holder has a tab receiving portion into which the insert member of the tab is inserted. The tab receiving portion is provided on the inner and outer surfaces thereof with a holder hole, which overlaps with a throughhole when the insert member is inserted. The diaphragm is disposed outside the tab receiving portion so as to cover the holder hole and electrically connected at its center bottom to the fragile portion via the holder hole. The gas pressure in the battery acts on the fragile portion and the inner side of the diaphragm.