Active Balancing System Using Buck Converter for Battery Cells
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Solution Overview
Problem
Conventional battery management systems are ineffective in maintaining balance between cells and modules in high-capacity batteries, leading to premature overcharging, over-discharging, and reduced service life, especially in large power storage applications like electric vehicles.
Innovation Solution
A self-contained battery active balancing system using a switch circuit and external power source or electronic flyback power converter to continuously balance cell voltages during charging, discharging, or idle states, ensuring all cells reach a balanced state efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If passive balancing is used to balance battery cells, then the circuit is simple and cost is low, but the balancing efficiency is low and the process takes a long time
Solution Approach 1:
The patent replaces passive resistive discharge (mechanical/electrical dissipation) with active power conversion using DC-DC converters. The converter actively transfers energy from high-voltage cells to low-voltage cells, substituting the passive mechanical-like discharge process with an active controlled energy transfer system, thereby dramatically improving balancing speed while maintaining circuit feasibility
Solution Approach 2:
The patent changes the balancing parameter from simple voltage equalization through resistance to active power transfer through DC-DC conversion. By monitoring cell voltages and using the converter to actively adjust energy distribution, the system achieves rapid balancing by dynamically changing energy parameters rather than relying on slow passive discharge
2Productivity
If active balancing is used to balance battery cells, then the balancing efficiency is high, but the device complexity increases
Solution Approach 1:
The patent integrates the DC-DC converter into the existing battery management system, making it serve dual functions: power conversion for active balancing and general battery management. This multi-functionality approach reduces overall system complexity by eliminating the need for separate dedicated balancing circuitry while maintaining high balancing efficiency
Solution Approach 2:
The patent merges the balancing function with the power management system by using the DC-DC converter that already exists for other battery operations. By combining multiple functions (power conversion, balancing, management) into a single integrated system, the patent reduces component count and system complexity while achieving active balancing
3Device complexity
If conventional battery management systems are used in high-capacity batteries, then the system is simple, but cells become unbalanced leading to overcharging and over-discharging
Solution Approach 1:
The patent implements continuous voltage monitoring of individual cells and uses feedback control through the DC-DC converter. The system constantly measures cell voltages, compares them against target values, and adjusts power transfer accordingly, creating a closed-loop feedback mechanism that maintains cell balance and prevents overcharging/over-discharging while managing system complexity
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
The system effectively extends battery endurance by preventing overcharging and over-discharging, maintaining optimal performance and prolonging the service life of batteries without requiring additional hardware.
Implementation Method 1
a buck converter having a first side winding and a second side winding induced by the first side winding
Data Source
AI summary
A battery active-balancing system comprises an external balancing power; a buck converter having a first side-winding and a second side-winding induced thereby, the first side-winding and the second side-winding each having a positive terminal and a negative terminal; a battery comprising series-connected cell-units each having a positive terminal and a negative terminal; a cell voltage-sensing unit coupled to the battery to sense a voltage of each cell unit of the series-connected cell-units; a main switch component coupled to the first side-winding and the battery in an ON state, or coupled to the first side-winding and the external balancing power in an OFF state; a cell-switch unit comprising first cell-switch components and second cell-switch components, wherein each of the first cell-switch components is coupled to the positive terminal of corresponding one cell-unit and the positive terminal of the second side-winding, and each of the second cell-switch components is coupled to the negative terminal of corresponding one cell-unit and the negative terminal of the second side-winding; and a microcontroller for controlling the main switch component and the cell-switch unit, and determining a voltage level fed back from the cell voltage-sensing unit.