Battery Cell Discharge via Balancing Circuit Post Crash
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Solution Overview
Problem
Existing systems for discharging high voltage vehicle batteries after a damaging event, such as a crash, do not effectively remove the stored energy, posing fire and chemical hazards, and are often expensive, heavy, and require significant space.
Innovation Solution
A system utilizing a battery controller and existing cell balancing circuits to slowly and individually discharge each battery cell in a high voltage vehicle battery, leveraging existing components to initiate and control the discharge process upon detection of a crash, using resistors and switches to dissipate voltage over time.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a stand alone embedded advanced monitoring system with DC/DC buck/boost converters and liquid cooled load banks is used to discharge the battery, then the battery can be discharged, but the system becomes expensive, heavy, and requires significant space
Solution Approach 1:
The cell balancing circuit, originally designed for maintaining equal charge levels across battery cells during normal operation, is repurposed to perform complete battery discharge after crashes. This multi-functional use eliminates the need for separate discharge equipment, reducing weight and space requirements while maintaining discharge capability
Solution Approach 2:
The battery system uses its own existing cell balancing circuitry to discharge itself after a crash event, controlled by the battery management unit. This self-service approach eliminates external discharge equipment, significantly reducing system weight, cost, and space requirements
2Reliability
If a stand alone embedded advanced monitoring system with DC/DC buck/boost converters and liquid cooled load banks is used to discharge the battery, then the battery can be discharged, but the system becomes expensive and requires significant space
Solution Approach 1:
The cell balancing circuit is designed to perform multiple functions: maintaining charge equality during normal operation and complete discharge after crashes. This eliminates the need for separate DC/DC converters and load banks, significantly reducing system complexity and cost
Solution Approach 2:
The invention extracts and utilizes the existing cell balancing circuitry from the battery management system to perform the discharge function, removing the need for separate expensive discharge equipment while maintaining the essential discharge capability
3Reliability
If battery disconnect units or manual service disconnects are used to isolate the battery, then electrical fault isolation is provided, but the stored charge remains in the battery creating fire hazards
Solution Approach 1:
The system performs preliminary discharge action immediately after detecting a crash event, before the vehicle is moved to a scrap yard or storage facility. This preliminary discharge eliminates fire hazards associated with stored charge, while the disconnect unit maintains electrical isolation
Solution Approach 2:
The invention converts the potentially harmful stored charge in the battery into a beneficial discharge process that eliminates fire hazards. The cell balancing circuit, normally used to maintain charge equality, is repurposed to safely dissipate the harmful stored energy as a beneficial safety feature
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 safely and automatically discharges battery cells, reducing fire risks and allowing for potential salvage of batteries, without adding weight, cost, or space to the vehicle, by utilizing existing components and control algorithms.
Implementation Method 1
The system includes a battery controller that monitors and controls the state-of-charge of each of the battery cells and a cell balancing circuit for maintaining the charge of the cells substantially equal
Data Source
AI summary
A system and method for individually discharging battery cells in a high voltage vehicle battery. The system includes a battery controller that monitors and controls the state-of-charge of each of the battery cells and a cell balancing circuit for maintaining the charge of the cells substantially equal. The controller receives a signal from a vehicle crash detector indicating that the vehicle has been in a crash, and in response instructs the cell balancing circuit to discharge all of the battery cells.