Battery Module Contactor Switching Between Series and Parallel
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Solution Overview
Problem
High voltage energy storage systems in electric vehicles present safety hazards due to increased voltage levels, requiring advanced contactor devices that can safely switch between series and parallel battery module connections to manage charging and power distribution effectively.
Innovation Solution
A contactor device with second bus bars and a connection bus bar, actuated by an element to switch between series and parallel connections, allowing for safe voltage application and charging within the high voltage energy storage system, incorporating deflectable contact regions and pyrotechnic actuators for overcurrent protection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If battery modules are connected in series to provide high voltage (400V-1kV) for vehicle operation, then power output capability is improved, but charging compatibility deteriorates because chargers cannot handle such high voltages
Solution Approach 1:
The contactor device dynamically reconfigures the battery module connections between series and parallel configurations based on operational requirements. During vehicle operation, modules are connected in series to provide high voltage (400V-1kV) for power output. During charging, the same modules are reconfigured in parallel to present a lower voltage interface that is compatible with standard chargers, thus resolving the contradiction between power output capability and charging compatibility
Solution Approach 2:
The system changes the electrical connection parameters of battery modules from fixed series connection to variable configuration. By using contactors to switch between series connection (for high voltage power output) and parallel connection (for low voltage charging), the system adapts its voltage and current parameters to match different operational modes, resolving the incompatibility between high voltage power delivery and charger compatibility
2Power
If battery voltage is increased to provide high power output, then driving capability is improved, but safety hazards worsen due to increased shock risk
Solution Approach 1:
The contactor device provides dynamic control over battery module connections, enabling the system to switch between high voltage series configuration (for driving capability) and low voltage parallel configuration (for safety during charging or maintenance). This dynamic reconfiguration reduces shock hazards by presenting lower voltage interfaces when high power output is not required, while maintaining full driving capability when needed
Solution Approach 2:
The contactor device acts as an intermediary between the high voltage battery modules and the external environment (chargers, maintenance equipment). By inserting controllable switching elements between the battery and external systems, the contactor mediates the voltage level exposure, allowing high voltage operation internally while providing safer interfaces externally, thus reducing shock hazards without compromising driving capability
3Device complexity
If a contactor device switches between open and closed states only, then device complexity is reduced, but functional versatility deteriorates because it cannot change battery configuration between series and parallel connections
Solution Approach 1:
The contactor device is segmented into multiple independent contactor units, each capable of controlling specific battery module connections. By dividing the overall switching function into separate contactors that can be independently controlled, the device achieves complex battery configuration changes (series to parallel transitions) while maintaining manageable individual component complexity. Each contactor handles a specific switching task, and their coordinated operation enables versatile battery configuration without requiring a single overly complex switching mechanism
Data Source
AI summary
The present invention relates to a contactor device (100), which is capable of changing a connection state of at least two battery modules (502(1), 502(2)) of a high voltage energy storage system (10) between a series connection and a parallel connection, and to an energy storage system (10) comprising the contactor device (100). The contactor device (100) comprises two first terminals (102, 104) for electrically connecting at least one of a load and a charger, two second terminals (106, 108) for electrically connecting a first battery module (502(1)), and two third terminals (110, 112) for electrically connecting a second battery module (502(2)). The contactor device (100) further comprises two first bus bars (128, 129), which each are electrically connected to one of the first terminals (102, 104), and two second bus bars (138, 139; 238, 239), wherein one of the second bus bars (138; 238) is electrically connected to one of the second terminals (106), and the other one of the second bus bars (139; 239) is electrically connected to one of the third terminals (112), and a connection bus bar (144), which is electrically isolated from the two first bus bars (128, 129). At least one actuation element is configured to change a state of the contactor device (100) at least to and from a series connection state, in which the two second bus bars (138, 139; 238, 239) are conductively coupled to the connection bus bar (144), and to and from a parallel connection state, in which one of the second bus bars (138; 238) is conductively coupled to one of the first bus bars (128) and the other one of the second bus bars (139; 239) is conductively coupled to the other one of the first bus bars (129).