Rail Vehicle Battery Management System Switch Control
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Solution Overview
Problem
Existing battery management systems in rail vehicles are complex, require significant wiring, and face challenges in reliable state-of-charge measurement, leading to potential interference and increased space requirements.
Innovation Solution
A centralized battery management system with a control unit, ballast, and integrated switching devices, allowing for controlled switching operations and compact design, utilizing a single ballast to manage multiple switching elements based on setpoints, and incorporating safety features for reliable operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a battery management system monitors all battery cells individually, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The battery management system divides the battery pack into series-connected groups of battery cells. Instead of monitoring each cell individually, the system measures the combined voltage of each group and calculates individual cell voltages through mathematical operations, reducing the number of direct measurement points while maintaining monitoring capability.
Solution Approach 2:
The system uses switching elements (switches) as intermediaries to selectively connect measurement points to different battery cell groups. These switches enable the same measurement circuit to serve multiple groups by reconfiguring connections dynamically, reducing the need for dedicated measurement circuits for each cell group.
2Adaptability or versatility
If switching elements are added to enable selective measurement, then adaptability is improved, but device complexity increases
Solution Approach 1:
The control unit combines multiple control signals into a unified switching control mechanism. The switching elements are integrated with the existing battery management system architecture, where the control unit manages both the measurement process and the switching operations through coordinated control, reducing overall system complexity despite adding switching capability.
Solution Approach 2:
The system implements dynamic reconfiguration of measurement circuits through controllable switches that can change connection states based on operational requirements. This allows the measurement system to adapt to different battery pack configurations and monitoring needs while maintaining a relatively simple hardware structure through software-controlled switching.
3Reliability
If individual battery cell monitoring is implemented, then reliability is improved, but loss of energy increases due to continuous monitoring
Solution Approach 1:
The system performs measurements in periodic cycles rather than continuously monitoring all cells simultaneously. The control unit activates measurement for specific battery cell groups at different time intervals, allowing the system to gather necessary data while reducing the total measurement time and associated energy consumption compared to continuous monitoring.
Solution Approach 2:
The system maintains continuous monitoring capability through rapid sequential measurement of different battery cell groups. By quickly switching between groups and performing measurements in succession, the system achieves near-continuous monitoring coverage while minimizing the time measurement circuits are active, thereby reducing energy loss while maintaining reliability.
Data Source
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AI summary
The invention relates to a battery management system (1), in particular for a rail vehicle, which comprises an system battery (12), a bus bar arrangement (14), a battery protection switch (10) for the controllable connection of the system battery to the bus bar arrangement (14), and at least one switching device (171-174) for the controllable connection of at least one load group (VG1-VGn) to the bus bar arrangement (14). Also provided are a control device (11) for controlling switching operations for switching the battery protection switch (10) and the at least one switching device (171-174) and a ballast (13) for generating a switching current for switching the battery protection switch (10) and the at least one switching device (171-174), wherein the control device (11) is designed to provide the ballast (13) with a set point for the switching current for switching the battery protection switch (10) or the at least one switching device (171-174).