Battery Module Switching for Pack Voltage Balancing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Voltage deviations among battery modules in battery packs lead to overcharging or overdischarging, causing degradation and reducing the lifespan of the battery pack, and replacing defective modules to achieve balance is cumbersome.
Innovation Solution
A battery system with a switching circuit and battery management system (BMS) that connects battery modules in series or parallel to balance voltages, using an external power conversion system to adjust power amounts, allowing modules to be connected in parallel for charging or discharging until voltage differences are within a predetermined reference value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If battery modules are connected in series to supply power, then the battery pack can provide high voltage output, but voltage deviation among modules causes overcharging or overdischarging that degrades battery life
Solution Approach 1:
The patent implements a dynamic switching circuit that can change the connection configuration between battery modules from series to parallel based on real-time voltage balance status. The BMS controller dynamically switches between series connection mode (for power delivery) and parallel connection mode (for voltage balancing), allowing the system to adapt its topology to maintain both high voltage output and battery reliability.
Solution Approach 2:
The patent changes the electrical connection parameter (series vs. parallel) of battery modules based on voltage deviation detection. When voltage imbalance exceeds a threshold, the system switches to parallel connection to equalize voltages; when balanced, it returns to series connection for power delivery. This parameter change resolves the contradiction by adjusting the connection mode to simultaneously achieve high voltage output and prevent degradation.
2Ease of repair
If a defective battery module is replaced, then the battery pack can restore functionality, but voltage deviation between pre-installed and new modules requires cumbersome manual balancing
Solution Approach 1:
The patent enables the battery system to perform automatic voltage balancing through the switching circuit and BMS controller after module replacement. Instead of requiring manual intervention to balance voltages between old and new modules, the system automatically detects voltage deviations and switches to parallel connection mode to equalize voltages, then returns to series mode. This self-service mechanism eliminates cumbersome manual balancing operations while maintaining ease of repair.
3Reliability
If manual voltage balancing is performed by charging or discharging individual modules, then voltage balance can be achieved, but the process is very cumbersome and inefficient
Solution Approach 1:
The patent merges multiple battery modules into parallel connection groups during the balancing process. Instead of charging or discharging individual modules separately, the switching circuit connects modules in parallel so they share the charging current automatically. This merging approach equalizes voltages across all modules simultaneously through the common parallel connection, dramatically improving balancing efficiency while maintaining reliable voltage balance.
Data Source
AI summary
A battery system may include a battery pack including a plurality of battery modules, a switching circuit connecting the plurality of battery modules in series or in parallel, and a battery management system (BMS) configured to control the switching circuit so as to connect the plurality of battery modules in series in a discharge mode to supply power from the battery pack to an external device and in a charge mode to charge the battery pack by receiving the power from the external device. In addition, the BMS may be configured to control entering a module balancing mode when a voltage difference among the plurality of battery modules exceeds a predetermined reference value, and control the switching circuit so as to connect the plurality of battery modules in parallel in the module balancing mode.