Battery Module Expansion-Triggered Short Circuit Safety Mechanism
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Solution Overview
Problem
Lithium secondary batteries face challenges with swelling phenomena due to decomposition reactions under abnormal conditions, leading to potential explosions and fires, and existing safety systems struggle to effectively manage short circuits caused by volume expansion.
Innovation Solution
A battery module design where a first busbar and a second busbar are electrically connected through an expansion force caused by volume increase, with a blow part to prevent overcharge by interrupting the electrical connection, using an elastic member and slide bar mechanism to ensure contact and a conductive short terminal for electrical connection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protection circuit and PTC element are used to prevent overcharge and short circuit, then safety is improved, but device complexity increases
Solution Approach 1:
The battery cell itself provides the protection function through its expansion force that activates the short part, eliminating the need for external protection circuits and PTC elements. The expansion of the battery cell directly causes the short part to move and establish electrical connection between busbars, creating a self-service safety mechanism.
Solution Approach 2:
The invention extracts and eliminates unnecessary protection components (protection circuits and PTC elements) by implementing a simplified safety mechanism that uses the battery cell's own expansion to trigger the short circuit protection, thereby reducing device complexity while maintaining safety.
2Reliability
If a protection circuit is used to interrupt current, then overcharge protection is improved, but ease of operation deteriorates due to normal range expansion causing short circuits
Solution Approach 1:
The invention changes the activation parameter from electrical detection (voltage/current thresholds in protection circuits) to mechanical parameter (expansion force). The short part remains inactive during normal expansion ranges and only activates when expansion force exceeds the threshold, distinguishing between normal and abnormal conditions.
Solution Approach 2:
The elastic member provides beforehand cushioning by absorbing normal expansion forces and only allowing the short part to move when abnormal expansion forces exceed the elastic member's buffering capacity, thus preventing false activation during normal operation.
3Reliability
If conventional safety systems are used, then basic protection is provided, but they cannot effectively manage short circuits caused by volume expansion beyond predetermined limits
Solution Approach 1:
The battery cell's own expansion serves as the activation mechanism for the safety system. The expansion force generated by the battery cell itself moves the short part to establish electrical connection, creating a self-service system that adapts to the battery's actual expansion state.
Solution Approach 2:
The short part acts as an intermediary that translates the battery cell's expansion force into electrical connection between busbars. This intermediary mechanism effectively manages expansion by converting mechanical expansion into an electrical safety response only when expansion exceeds safe limits.
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 prevents overcharge and improves stability by establishing a short circuit and blowing a fuse-like mechanism to interrupt power, thereby preventing further charging and reducing the risk of explosions and fires.
Implementation Method 1
a short part comprising an elastic member and a slide bar, the slide bar having one end connected to the elastic member and the other end forming a short terminal, the elastic member providing an elastic force in a direction facing the first busbar and the second busbar when the elastic member is deformed, and the slide bar maintaining the elastic member in a deformed state by latch coupling of a latching part protruding at one end to produce the elastic force
Implementation Method 2
by the application of an expansion force caused by volume increase of the first battery cell, the short part moves to the first busbar and the second busbar and comes into contact with the first busbar and the second busbar
Data Source
AI summary
A battery module according to the present disclosure includes a first busbar electrically connected to a first electrode lead of a first battery cell, a second busbar electrically connected to a second electrode lead of a second battery cell, a short part which moves to the first busbar and the second busbar and comes into contact with the first busbar and the second busbar by the application of an expansion force caused by volume increase of the first battery cell to electrically connect the first busbar to the second busbar, causing a short, and a cartridge which receives or supports at least part of the first electrode lead, the second electrode lead, the first busbar, the second busbar and the short part.