Battery Cell Rapid Discharge Unit for Thermal Runaway Prevention
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Solution Overview
Problem
Battery cells can exhibit hazardous behavior such as thermal runaway, degassing, fire, or explosion due to defects or excessive loading, which existing technologies fail to effectively prevent by controlling ion permeability and heat management.
Innovation Solution
A battery cell design with two terminals and an electrochemical jelly roll configuration, incorporating a rapid discharge unit with a predefined resistance value that activates a separator to become impermeable to ions, reducing discharge current and heat buildup in hazardous situations, thereby preventing thermal runaway.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a rapid discharge unit with predefined resistance is activated to reduce discharge current and heat, then thermal runaway is prevented, but the battery cell cannot deliver high current when needed
Solution Approach 1:
The rapid discharge unit is dynamically activated only when hazardous conditions are detected (temperature threshold or short-circuit detection), allowing the battery to maintain high power capability during normal operation while providing safety protection when needed. The unit can be switched in and out based on real-time monitoring of temperature and current parameters.
Solution Approach 2:
The system changes the resistance parameter of the discharge path by activating the rapid discharge unit with predefined resistance only when hazardous conditions are detected. During normal operation, the battery operates with its natural low resistance for high power delivery, but switches to high resistance mode when safety threats are identified.
2Reliability
If the separator is deactivated to become impermeable to ions to stop harmful reactions, then thermal runaway is prevented, but the battery cell loses its functionality
Solution Approach 1:
The separator's ion permeability is dynamically controlled based on temperature conditions. At normal operating temperatures, the separator remains permeable to allow ion transport and maintain battery functionality. When the temperature exceeds the predefined threshold, the separator automatically becomes impermeable, stopping ion transport and preventing thermal runaway.
Solution Approach 2:
The separator undergoes a parameter change in its ion permeability property based on temperature. Below the threshold temperature, the separator maintains high ion permeability for normal battery operation. Above the threshold, the separator transitions to an impermeable state, effectively shutting down the electrochemical reactions to prevent thermal runaway.
3Reliability
If a short-circuit path exists in the battery cell, then high discharge current flows causing rapid heat-up, but the separator cannot become impermeable quickly enough to prevent thermal runaway
Solution Approach 1:
The system performs preliminary detection of short-circuit conditions through monitoring voltage drops or current anomalies before the separator deactivation process begins. This early detection allows the rapid discharge unit to be activated immediately when a hazard is detected, reducing the time delay between short-circuit occurrence and protective action.
Solution Approach 2:
The rapid discharge unit acts as an intermediary protective mechanism that activates between the short-circuit condition and the separator deactivation. It provides immediate current limiting and heat management while the separator deactivation process occurs, bridging the time gap and preventing thermal runaway during the transition period.
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 reduces discharge current and heat in battery cells, preventing thermal runaway and hazardous behavior by partially deactivating the separator, even in the presence of a short-circuit path, thus ensuring safer operation.
Implementation Method 1
a rapid discharge unit, which is connectable between the battery cell terminals and has a predefined resistance value. The predefined resistance value is selected such that, when the rapid discharge unit is brought into circuit, the at least one separator achieves the predefined temperature
Implementation Method 2
Upon the achievement of a predefined temperature, the at least one separator is at least partially impermeable to ions which can be generated in the electrochemical part
Data Source
AI summary
A battery cell (10) with two battery cell terminals (11, 12) which are contactable from inside and/or outside the battery cell (10), and an electrochemical part (20) comprising at least one separator. Upon the achievement of a predefined temperature, the at least one separator is at least partially impermeable to ions which can be generated in the electrochemical part (20). The battery cell (10) has a rapid discharge unit (30), which is connectable between the battery cell terminals (11, 12) and which, in a switched-in and consequently activated state, has a predefined resistance value. The predefined resistance value is selected such that, with the rapid discharge unit (30) switched-in, the at least one separator achieves the predefined temperature.