Battery Pack Measurement Synchronization for Wireless BMS Timing
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Solution Overview
Problem
In wireless communication-based battery management systems, the lack of synchronization in voltage and current measurement timing between lower-level and upper-level battery management systems prevents accurate estimation of remaining capacity, life, and available power without a control signal from a host controller.
Innovation Solution
A battery management system that includes a pack voltage sampling unit, a pack current sampling unit, and a control unit to synchronize voltage and current measurements by transmitting a synchronization signal and calculating synchronization times, allowing for internal synchronization without external control signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If wireless communication-based system structure with multiple battery management systems is used, then system flexibility and distributed control are improved, but measurement timing synchronization between upper-level and lower-level BMS deteriorates
Solution Approach 1:
The upper-level BMS transmits a voltage sampling synchronization signal before the actual sampling process to pre-coordinate the measurement timing. This preliminary synchronization action ensures that both upper-level and lower-level BMS perform voltage and current measurements at consistent timing points, resolving the timing synchronization issue while maintaining system flexibility
Solution Approach 2:
The lower-level BMS measures cell voltage and pack voltage, then feeds back the measurement timing information (second time) to the upper-level BMS. The upper-level BMS uses this feedback to perform sampling synchronization by comparing the feedback timing with its own measurement timing (first time), ensuring accurate timing alignment across the distributed system
2Device complexity
If individual voltage and current measurement by each BMS is performed, then measurement independence and system modularity are improved, but timing consistency of measurement points deteriorates
Solution Approach 1:
The system merges the timing reference of upper-level and lower-level BMS by using the synchronization signal and timing feedback mechanism. Although the BMS remain modular and independent, their measurement timing is combined through the synchronization process, ensuring timing consistency is achieved while preserving system modularity
Solution Approach 2:
The voltage sampling synchronization signal acts as an intermediary that coordinates between upper-level and lower-level BMS. This intermediary signal enables timing alignment without requiring direct control or coupling between the modular components, maintaining both independence and consistency
Data Source
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AI summary
The present invention relates to a battery management system and a battery pack and the battery management system according to an embodiment of the present invention includes: a pack voltage sampling unit configured to periodically sample a pack voltage of a battery pack; a pack current sampling unit configured to sample a pack current of the battery pack; and a control unit configured to, after starting to sample the pack voltage of the battery pack, when the pack voltage sampling of the battery pack is completed, record a time from a sampling start time of the pack voltage to a sampling completion time of the pack voltage as a first time, and transmit a voltage sampling synchronization signal for measuring a cell voltage of a battery cell to a plurality of lower-level battery management systems, wherein the control unit performs sampling synchronization on the sampled measurement signal between each lower-level battery management system based on a second time, which is a sampling time at which a cell voltage measurement received from each lower-level battery management system is performed, and the first time.