Battery Pack Contactor Status Verification for 400V/800V Switching
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Solution Overview
Problem
The increased risk of failure and potential for short-circuits in battery packs with multiple contactors, particularly when switching between 400V and 800V charging modes, poses a safety concern due to the higher number of contactors required, which can lead to increased failure rates and risks of fires or explosions.
Innovation Solution
A control method and system for a battery pack that includes multiple switching elements and sensors to determine the status of each switching element, preventing simultaneous closure of certain elements to ensure none are stuck in a closed status, thereby reducing the risk of short-circuits and improving safety by verifying all elements are open before allowing them to close.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a battery pack uses multiple contactors to enable switching between 400V and 800V charging modes, then the adaptability and charging speed are improved, but the number of contactors increases leading to higher failure risk and safety hazards
Solution Approach 1:
The control method performs preliminary verification by detecting the status of all contactors before switching operations. The system checks whether all contactors are in the open state before closing any contactor, preventing unsafe switching conditions from occurring in the first place
Solution Approach 2:
The system continuously monitors and detects the status of each contactor through voltage detection. This feedback mechanism allows the control unit to make informed decisions about when to close or open contactors, ensuring safe operation by basing control actions on real-time status information
2Power
If a battery pack uses more contactors to handle both 400V and 800V charging, then the power and charging capability are improved, but the complexity of the system increases leading to more potential failure points
Solution Approach 1:
Instead of trying to manage the complexity of multiple contactors through complex control logic, the invention inverts the approach by using a simple verification rule: check if all contactors are open before closing any. This simplifies the control strategy while maintaining safety
Solution Approach 2:
The invention replaces complex mechanical interlocking mechanisms with an electrical detection and control system. The control unit uses voltage detection to monitor contactor status and automatically controls the switching sequence, eliminating the need for complex mechanical safety devices
Data Source
Figure 1
Figure 2A~2B
Figure 3
AI summary
A control method of a battery pack, wherein the battery pack comprises: a first node (HV+) and a second node (HV-), a first battery string (100) and a second battery string (200), and a plurality of switching elements (SW1, SW2, SW3, SW4, SW5). The method comprises: controlling the plurality of switching elements to open; measuring the respective voltages on each terminal of each of the plurality of switching elements by using a plurality of sensors; determining a status of each of the plurality of switching elements being open or closed; when the switching element SW5 is controlled to close, preventing any of the switching elements SW1 or SW4 from being closed, until determining the status of each of the plurality of switching elements being open; when any of the switching elements SW1 or SW4 is controlled to close, preventing the switching element SW5 from being closed, until determining the status of each of the plurality of switching elements being open.