Daisy-Chain Battery Balancing Circuit for Mismatched Cell Packs
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Solution Overview
Problem
Battery modules composed of multiple cells with varying charging status, impedance, and temperature characteristics result in reduced capacity and lifespan due to mis-matched cells, necessitating effective balance control for stable performance, especially in applications like electric vehicles and energy storage systems.
Innovation Solution
A balance control circuit and system that groups battery cells into sub-groups, utilizing a daisy chain configuration of balance control circuits with digital coded pulse trains to equalize cell voltages through active energy transfer, enhancing efficiency and reliability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple battery cells are connected in series to achieve high output voltage, then the output voltage is improved, but the capacity and lifespan are reduced due to mis-matched cells
Solution Approach 1:
The patent segments the battery group into multiple sub-groups, with each balance control circuit managing a specific sub-group. This segmentation allows independent balancing control for each sub-group, addressing the mis-matched cell issue while maintaining the high voltage series connection structure.
Solution Approach 2:
The balance control circuits are configured in a dynamic daisy chain topology that can selectively activate different balancing paths based on real-time cell voltage differences. This dynamic configuration enables adaptive balancing control to optimize both voltage output and cell matching.
2Reliability
If balance control is implemented to balance the cells, then the capacity and stable performance are improved, but the system complexity increases
Solution Approach 1:
Multiple balance control circuits are merged into a unified daisy chain configuration, where circuits share common signal transmission lines and control protocols. This merging approach reduces overall system complexity compared to independent control systems while maintaining effective balancing capability across all sub-groups.
Solution Approach 2:
Each balance control circuit in the daisy chain is designed with universal functionality to handle multiple tasks: voltage measurement, balancing control, and signal transmission to adjacent circuits. This multi-functionality reduces the need for separate dedicated components, simplifying the overall system.
3Productivity
If a daisy chain configuration of balance control circuits is used, then the balancing efficiency is improved, but the communication complexity increases
Solution Approach 1:
The balance control signal uses periodic digital coded pulse trains transmitted through the daisy chain. This periodic signaling approach enables efficient data transmission between circuits while using simple, standardized pulse protocols that reduce communication complexity compared to continuous analog signaling.
Data Source
AI summary
A balance control circuit and other balance control circuits are coupled in a daisy chain configuration for balancing a battery group with a plurality of battery cells. The plurality of battery cells are grouped into multiple sub-groups in which a nth cell (n≥3) is shared by two adjacent sub-groups. The balance control circuit has a first cell pin coupled to a cathode of a first battery cell, a second cell pin to a (n+1)th cell pin coupled by ordinal to an anode of the first battery cell to an anode of the nth battery cell, a digital input terminal for receiving a balance control signal with digital coded pulse train, and a high-side transmission terminal operable for transmitting the balance control signal to a digital input terminal of a latter balance control circuit in the daisy chain.