Dual Battery Modules for Flexible EV Charging
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Solution Overview
Problem
Existing electric vehicle battery management systems lack flexibility in charging and propulsion modes, particularly in high-current DC fast-charging scenarios, and do not efficiently balance state of charge across multiple battery modules, limiting operating flexibility and requiring redundant hardware.
Innovation Solution
A dual-rechargeable energy storage system (RESS) topology with identically configured battery modules that use a split-charge approach with the same charging voltage, enabling parallel charging and independent operation of front and rear propulsion systems, and utilizing a controller to manage switching states for various operating modes without the need for high-current hardware redesign.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single battery module is used in conventional RESS, then the hardware configuration is simple, but the operating mode flexibility and state of charge balancing capability are limited
Solution Approach 1:
The battery pack is divided into multiple identical battery modules (first battery module and second battery module), each capable of independent operation. This segmentation enables flexible configuration where modules can be charged or discharged independently or in parallel, providing multiple operating modes without requiring fundamentally different hardware designs.
Solution Approach 2:
Each battery module is designed with universal functionality to perform multiple roles: they can be charged independently, discharged independently to power different drive units, or operated in parallel for combined power delivery. The identical configuration of both modules enables this multi-functionality while maintaining hardware simplicity.
2Productivity
If high-current DC fast-charging is implemented, then charging speed increases, but the current through battery pack components increases requiring higher-current hardware
Solution Approach 1:
The charging current is divided and distributed to multiple battery modules in parallel. By splitting the high-current charging path across multiple identical modules, each module handles a portion of the total current, allowing the system to accept high-power fast charging without requiring each individual component to be rated for the full high current.
Solution Approach 2:
Multiple battery modules are connected in parallel to collectively handle high-current charging operations. The combined capacity of multiple modules sharing the charging load enables the system to accept high-power DC fast charging while individual components operate at lower, more manageable current levels.
3Adaptability or versatility
If battery modules are charged in series, then the same charging current flows through all modules, but the charging voltage distribution becomes inflexible and balancing capability is reduced
Solution Approach 1:
The system dynamically switches between different charging configurations (independent charging, parallel charging, series charging) based on operational requirements and state of charge levels of individual modules. This dynamic reconfiguration capability enables flexible state of charge balancing while maintaining manageable system complexity through standardized module interfaces.
Data Source
AI summary
An electrical system includes cables, a DC charge connector, first and second battery modules, a splice device, and a controller. Each battery module has first, second, third, and fourth electrical connectors receiving a respective one of the cables. The battery modules are connected to each other via the cables, and further have first, second, third, and fourth switches that connect battery cell strings to one or more connectors. The charge connector is connected to one of the cables between the first electrical connectors. The splice device connects the charge connector to the first connector of the first battery module and to a pair of the cables. A charging current may be split between the battery modules. The controller selectively establishes parallel charging, parallel drive, and separate drive and charging modes for each battery module. The system may have an independent drive mode.