Battery Module Cell Balancing With Isolated DC/DC Converters
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Solution Overview
Problem
Existing energy storage systems face challenges in efficiently equalizing cell voltages across multiple battery cells connected in series, which can lead to reduced system efficiency and increased costs.
Innovation Solution
The proposed energy storage system incorporates a plurality of isolated DC/DC converters, each connected between two adjacent battery cells, to equalize cell voltages. A controller manages the charge and discharge modes of these converters, ensuring that the average voltage of the battery cells is maintained.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional voltage equalization methods are used in energy storage systems, then system complexity is reduced, but cell voltage equalization efficiency deteriorates and additional components are required
Solution Approach 1:
The system uses the battery cells themselves to perform voltage equalization by having higher-voltage cells discharge and lower-voltage cells charge through DC/DC converters, eliminating the need for external equalization circuits or resistors. Each battery cell serves dual purposes: energy storage and voltage equalization.
Solution Approach 2:
The DC/DC converters are designed to perform multiple functions: primary power conversion for energy storage and secondary voltage equalization for cell balancing. This multi-functionality eliminates the need for separate equalization components, reducing system complexity while improving equalization efficiency.
2Productivity
If multiple isolated DC/DC converters are used for cell voltage equalization, then equalization efficiency is improved, but the number of components increases
Solution Approach 1:
The DC/DC converters perform both power conversion and voltage equalization functions simultaneously. By designing the converters to operate in different modes (power transmission mode and equalization mode), the system achieves efficient cell balancing without requiring additional dedicated equalization components.
Solution Approach 2:
The voltage equalization function is merged into the existing DC/DC converter architecture. The control unit integrates both power management and voltage equalization control, combining what would traditionally be separate functions into a unified system that reduces overall component count.
3Reliability
If additional components are added to manage voltage disparities, then voltage equalization is improved, but system cost increases
Solution Approach 1:
The system achieves voltage equalization using existing battery cells and DC/DC converters without requiring additional external equalization circuits, resistors, or specialized components. This self-service approach maintains reliable voltage balancing while minimizing system cost by utilizing already-present hardware.
Solution Approach 2:
By designing DC/DC converters that can operate in both power conversion mode and voltage equalization mode, the system eliminates the need for separate equalization components. This multi-functionality reduces bill of materials costs and simplifies manufacturing while maintaining effective voltage equalization capability.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution effectively equalizes cell voltages, improving the efficiency of the energy storage system, reducing the need for additional components to manage voltage disparities, and lowering overall system costs.
Implementation Method 1
a plurality of isolated DC/DC converters, each isolated DC/DC converter having one end connected to one battery cell and an other end connected to another battery cell adjacent to the one battery cell so as to equalize a cell voltage between two battery cells
Data Source
AI summary
An energy storage system including one or more battery cells connected in series, one or more isolated DC/DC converters, each isolated DC/DC converter having one end connected to one battery cell and an other end connected to another battery cell adjacent to the one battery cell so as to equalize a cell voltage through charging and discharging of the two battery cells which are each electrically connected to one of the plurality of battery cells, and a plurality of battery modules each including a controller configured to control a charge mode and a discharge mode of the plurality of isolated DC/DC converters.