Battery Pack Leakage Current Blocking via BMS Switching Circuit
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Solution Overview
Problem
Battery packs used in electric vehicles face performance degradation due to leakage currents when the power source is turned off, which is not effectively managed by existing battery management systems (BMS).
Innovation Solution
A battery pack with a BMS that includes a battery controller and a switching circuit to block control currents based on predetermined conditions, such as time or changes in open circuit voltage, ensuring the control current is turned off when the battery controller receives a turn-off command, and turned on when necessary using a turn-on current or voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the battery controller remains active after power-off, then the battery can respond quickly to restart commands, but leakage current continues to drain battery power
Solution Approach 1:
The battery controller dynamically changes its operational state based on system conditions. It transitions from an active state during normal operation to a suspended state after power-off, allowing it to respond quickly when needed while minimizing power consumption during idle periods. This dynamic state change resolves the contradiction between maintaining response readiness and reducing leakage current.
Solution Approach 2:
The battery controller monitors its own operational status and automatically suspends its operations after detecting a power-off condition. This self-service mechanism allows the controller to manage its own power consumption without requiring external intervention, effectively reducing leakage current while maintaining the capability to restart when needed.
2Loss of energy
If the battery controller is completely turned off, then leakage current is minimized, but the battery cannot be managed or monitored
Solution Approach 1:
The battery controller's functionality is segmented into essential and non-essential operations. After power-off, non-essential operations are suspended to reduce power consumption, while essential monitoring functions remain active to maintain battery management capability. This segmentation allows the system to minimize power consumption without completely sacrificing reliability.
Solution Approach 2:
Different functional modules within the battery controller have different operational requirements. The invention applies local quality by allowing certain modules to remain active for monitoring while suspending others for power savings. This selective operation maintains necessary battery management capabilities while minimizing overall power consumption.
3Ease of operation
If the switching circuit operates continuously, then the control current is always available, but the system complexity increases
Solution Approach 1:
The switching circuit operates periodically rather than continuously. It activates during normal operation to provide control current, suspends after power-off to reduce complexity, and can be quickly reactivated when needed. This periodic operation reduces the effective complexity of the switching circuit while maintaining control current availability when required.
Data Source
AI summary
A battery pack includes a battery to supply power for a device and a battery management system (BMS) to manage the battery. A control current from the battery to the BMS is to be blocked based on a turn-off command.