Battery Cell Venting That Triggers Safe Discharge After Pressure Release
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Solution Overview
Problem
Typical Li-ion battery cells are prone to catching fire during electrical or physical abuse, posing hazards due to their inability to safely fail and discharge energy, which can lead to property damage and operator safety risks.
Innovation Solution
An electrochemical cell design that incorporates a venting mechanism to intentionally discharge the cell by electrically shorting the positive and negative electrodes upon pressure release, reducing the risk of fire by maintaining internal pressure above atmospheric levels and utilizing a liquefied gas electrolyte to minimize heat generation during discharge.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If Li-ion battery cells are designed with integrated safety devices such as current interrupt devices, pressure release vents, and thermal switches, then safety under abuse conditions is improved, but the device complexity increases
Solution Approach 1:
The patent combines multiple safety functions into a single integrated vent mechanism. The vent assembly integrates pressure release, electrical shorting, and thermal management functions into one component, eliminating the need for separate current interrupt devices, pressure release vents, and thermal switches while maintaining comprehensive safety protection
Solution Approach 2:
The vent assembly serves multiple functions simultaneously: it releases excess pressure, creates an electrical short between electrodes to discharge stored energy, and provides a thermal management pathway. This multi-functional design reduces overall device complexity while improving reliability through coordinated safety responses
2Stability of the object's composition
If the cell is designed to maintain internal pressure above atmospheric pressure, then the liquefied gas electrolyte remains in liquid phase, but the risk of fire increases under abuse conditions
Solution Approach 1:
The vent assembly is pre-configured with conductive elements positioned to automatically create an electrical short when the cell undergoes abuse conditions. This preliminary arrangement ensures that when pressure exceeds the threshold, the vent not only releases pressure but also immediately discharges stored electrical energy through the short circuit path, preventing fire before it can occur
Solution Approach 2:
The patent converts the harmful effect of high internal pressure, which normally indicates a dangerous condition, into a beneficial trigger mechanism. The excess pressure that would otherwise lead to catastrophic failure is instead used to activate the vent assembly, which simultaneously releases pressure and creates an electrical short to safely discharge energy, transforming a hazard into a safety mechanism
3Stress or pressure
If the vent releases the housing from the lid assembly when predetermined internal pressure is exceeded, then the internal pressure is vented, but the cell remains charged and continues to pose fire hazards
Solution Approach 1:
The vent assembly merges pressure release and electrical discharge functions into a single coordinated action. When the vent opens to release pressure, the same mechanical movement simultaneously brings conductive elements into contact, creating an electrical short that discharges the cell. This combined action ensures that pressure relief is never separated from energy discharge, eliminating the fire hazard that would persist with pressure-only venting
Solution Approach 2:
The conductive elements are pre-positioned within the vent assembly such that the act of opening the vent automatically triggers the electrical short. This preliminary configuration ensures that the discharge action is inseparable from the pressure release action, so that every time the cell vents pressure, it simultaneously discharges stored energy and eliminates fire hazards
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 design ensures safe failure of the cell by significantly reducing stored energy, minimizing the risk of fire and other hazards, and allows for safer handling and recycling by discharging the cell, thereby enhancing safety and reducing costs associated with battery recycling.
Implementation Method 1
the vent releasing the housing from the lid assembly when a predetermined internal pressure is exceeded
Implementation Method 2
the venting dislodging the lid assembly such that it makes electrical contact with the housing, thus discharging the cell
Implementation Method 3
utilizing a liquefied gas electrolyte to minimize heat generation during discharge
Data Source
AI summary
The present invention discloses an electrochemical cell design that safely discharges after cell venting. The cell includes a housing and a lid assembly connected to the housing via a vent. The housing houses an electrode assembly with a first electrode separated from a second electrode by a separator. The first electrode is electrically connected to the housing, and the second electrode is electrically connected to the lid assembly structure. The cell has a non-venting configuration characterized by the vent connecting the lid assembly to the housing such that the internal pressure is maintained at a pressure above atmospheric pressure. A venting configuration is characterized by (A) the vent releasing the housing from the lid assembly when a predetermined internal pressure is exceeded; (B) venting the internal pressure; and (C) the venting dislodging the lid assembly such that it makes electrical contact with the housing, thus discharging the cell.