Battery Equalization Circuit for Direct Cell-to-Cell Energy Transfer
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Solution Overview
Problem
Conventional battery equalization systems either waste energy or require complex multi-level structures, and they cannot achieve direct voltage equalization between any batteries, necessitating continuous voltage detection and closed-loop control.
Innovation Solution
An active equalization control system comprising a battery module and an active equalizer, which includes a sampling circuit, a processor, and an active equalization circuit. The system collects analog voltages from batteries, converts them to digital, and generates signals for selecting target batteries and equalizing their voltages using a power conversion circuit with four transistors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive equalization control strategy is used, then voltage balance between batteries is achieved, but battery energy is wasted
Solution Approach 1:
The patent introduces a DC-DC converter as an intermediary device between batteries to enable active equalization. The converter transfers energy from high-voltage batteries to low-voltage batteries through controlled power conversion, avoiding direct energy dissipation while achieving voltage balance across all battery cells.
2Device complexity
If non-quarantine-type active equalization strategy is used, then system complexity is reduced, but operation safety is lowered
Solution Approach 1:
The patent segments the battery management system into independent control modules, each responsible for specific equalization tasks. The DC-DC converter is divided into multiple independent channels that can operate autonomously, allowing simplified control architecture while maintaining safety through modular fault isolation and individual channel monitoring.
3Reliability
If quarantine-type active equalization strategy is used, then operation safety is improved, but system complexity increases
Solution Approach 1:
The patent implements preliminary detection and classification of battery voltage states before equalization begins. The system pre-identifies high-voltage and low-voltage battery groups, pre-configures DC-DC converter channels, and establishes control parameters in advance, enabling safe quarantine-type equalization without requiring complex real-time decision-making during operation.
4Ease of operation
If direct voltage equalization between any batteries is not implemented, then control simplicity is maintained, but equalization efficiency is reduced
Solution Approach 1:
The patent designs the DC-DC converter with universal multi-functional capability to support equalization between any pair of batteries. The converter channels can be dynamically configured and switched to connect any high-voltage battery with any low-voltage battery, providing direct equalization paths while maintaining simplified control through standardized conversion topology and unified control algorithms.
Data Source
AI summary
Provided are an active equalization control system and an active equalization control method. The active equalization control system includes a sampling circuit; a processor configured to generate a battery selection signal and a target pulse width modulation signal; and an active equalization circuit. The active equalization circuit includes a battery selection circuit configured to select two target batteries to perform voltage equalization according to the battery selection signal; and a power conversion circuit configured to equalize voltages of the two target batteries according to the target pulse width modulation signal.