Battery BMS Cell Discharge Fencing Against Thermal Runaway
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Solution Overview
Problem
In battery packs, a failing battery cell can cause thermal runaway, leading to damage or failure of nearby cells, potentially resulting in a cascading failure and destruction of the battery pack.
Innovation Solution
A battery management system (BMS) that identifies failing cells and strategically discharges adjacent cells to a lower State of Charge (SOC), creating a protective 'fence' to prevent the failure from spreading.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If multiple battery cells are packed in close proximity to achieve high energy density, then the energy density and compactness of the battery pack are improved, but the risk of thermal runaway propagation to neighboring cells increases
Solution Approach 1:
The battery pack is divided into modular cell groups, where each group can be independently managed and disconnected. When thermal runaway is detected in one cell, the system segments the affected group from the rest of the battery pack using disconnect switches, preventing propagation while maintaining the overall compact structure.
Solution Approach 2:
Thermal barrier materials and heat dissipation structures are introduced as intermediary elements between adjacent battery cells. These intermediaries absorb and redirect heat away from neighboring cells, breaking the direct thermal coupling pathway while allowing cells to remain in close proximity for high energy density.
2Reliability
If a failing battery cell is isolated from the discharging system to prevent failure propagation, then the reliability of the remaining cells is improved, but the overall power output and energy utilization of the battery pack decreases
Solution Approach 1:
The battery pack uses modular architecture with independent cell groups connected through switchable circuitry. When a cell fails, only the affected group is disconnected from the discharging system, while other groups remain operational, maintaining partial power output and improving overall system reliability.
Solution Approach 2:
The system dynamically changes the operational parameters of the battery pack by adjusting which cell groups are connected to the discharging system. When thermal runaway is detected, the system changes the connection state of affected cells while maintaining optimal discharge parameters for healthy cells, balancing reliability and productivity.
3Object-affected harmful factors
If adjacent battery cells are discharged to a lower State of Charge as a protective measure, then the risk of failure propagation is reduced, but the available energy and power capacity of the battery pack decreases
Solution Approach 1:
The system performs preliminary discharge of adjacent cells to a lower State of Charge before thermal runaway occurs. By proactively reducing the charge level of neighboring cells when a failing cell is detected, the system creates an energy buffer that reduces propagation risk while minimizing the impact on overall energy capacity.
Solution Approach 2:
The BMS dynamically adjusts the State of Charge parameters of different cell groups based on real-time conditions. Healthy cells can operate at higher SOC for maximum energy utilization, while cells adjacent to failing cells are operated at lower SOC for enhanced safety, optimizing the trade-off between energy capacity and failure propagation prevention.
Data Source
AI summary
Aspects of the present disclosure include systems, apparatuses, or methods for a system for reducing battery cell failure propagation risk includes a rechargeable battery including a plurality of rechargeable cells connected in series, parallel, or a combination of series and parallel and a BMS coupled with the battery. The BMS includes a processor and a memory including computer-executable instructions to receive information indicative of a status of each of the rechargeable cells; determine that a particular rechargeable cell is likely in a failure condition; identify a group of rechargeable cells that is in within one hop of the rechargeable cell that is likely in the failure condition; couple the group of rechargeable cells to a discharging system without coupling the rechargeable cell in the failure condition to the discharging system; and discharge the group of rechargeable cells to a target SOC.