Battery Cell Internal Short Simulation via Electrical Cycling
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Solution Overview
Problem
Existing methods for testing battery packs to simulate internal short circuits unrealistically alter the thermal environment and reaction characteristics, making it difficult to accurately assess the response of battery packs to thermal runaway events.
Innovation Solution
A test apparatus and method that simulates an internal cell short by using rapid charge and discharge cycles at high currents, allowing for modulation of current magnitude to replicate various power profiles while maintaining the thermal environment's integrity and avoiding interference with neighboring cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conductive overheating is used to simulate internal short, then the heating profile can be selected and state-of-charge is preserved, but the thermal environment of the battery pack is dramatically altered by introducing extra thermal mass and requiring pack modification
Solution Approach 1:
The patent replaces the mechanical/thermal approach (conductive overheating with heating coils) with an electrical approach (applying controlled current directly to the cell terminals). This substitution eliminates the need for physical heating elements and pack modifications while maintaining precise control over the heating profile through electrical parameters.
Solution Approach 2:
The invention extracts the heating function from the thermal environment and relocates it to the electrical domain. By applying current directly to the cell terminals, the heating effect is generated internally within the cell itself rather than being introduced from an external thermal source, thereby eliminating the need for pack modifications and extra thermal mass.
2Measurement precision
If conductive overheating is used to simulate internal short, then heating profile can be selected, but adjacent cells may be excessively heated before thermal runaway occurs
Solution Approach 1:
The patent applies heating locally and selectively to only the target cell by connecting the current source directly to its terminals. This localized electrical heating ensures that thermal energy is generated exclusively within the intended cell, preventing excessive heating of adjacent cells and maintaining the integrity of the thermal environment for other cells in the pack.
Solution Approach 2:
By replacing the thermal conduction method with direct electrical current application, the invention achieves precise spatial control over heating. The electrical current flows only through the targeted cell, converting electrical energy to thermal energy internally, thereby eliminating the thermal spread to adjacent cells that occurs with conductive overheating methods.
3Temperature
If overcharging is used to simulate internal short, then the thermal environment surrounding cells is preserved, but the character of the thermal runaway reaction is changed to be more energetic
Solution Approach 1:
The patent changes the controlling parameter from chemical (overcharging state) to electrical (applied current magnitude and waveform). By controlling the electrical current applied to the cell terminals, the invention can induce thermal runaway with a character that closely matches spontaneous internal shorts, while maintaining the natural thermal environment of the battery pack without the distorted reaction characteristics caused by overcharging.
4Temperature
If overcharging is used to simulate internal short, then thermal environment is preserved, but it is difficult to simulate internal shorts of various magnitudes
Solution Approach 1:
The patent introduces dynamic control of the electrical current parameters (magnitude, waveform, duration) to simulate various internal short magnitudes. This dynamic electrical control allows the system to replicate different short circuit scenarios by adjusting current parameters, providing versatility in simulating various short magnitudes while preserving the natural thermal environment of the battery pack.
Solution Approach 2:
By changing the electrical parameters (current magnitude, pulse duration, waveform characteristics) of the applied current, the invention can simulate internal shorts of various magnitudes. This parameter-based control offers greater adaptability compared to fixed overcharging methods, allowing precise replication of different short circuit scenarios while maintaining the authentic thermal environment.
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
This approach allows for accurate simulation of internal short events with minimal impact on the thermal environment, enabling precise characterization of battery pack response to thermal runaway without altering the thermal conditions or introducing extra thermal mass.
Implementation Method 1
A test apparatus and method that simulates an internal cell short by using rapid charge and discharge cycles at high currents
Data Source
AI summary
A test apparatus and corresponding method for simulating an internal cell short and initiating thermal runaway in a battery cell is disclosed whereby the cell is internally heated through rapid charge and discharge cycles at high currents. The magnitude of the selected current may be modulated to simulate a cell short with the desired power profile without unrealistically heating neighboring cells or interfering with the thermal environment of the cell within the module.