Series Cell Balancing Power Supply for Efficient Hybrid Equalization
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Solution Overview
Problem
Existing methods for equalizing lithium-ion cell voltages in series-connected systems suffer from reduced power efficiency due to energy loss in passive methods and increased complexity and cost in active methods.
Innovation Solution
A power supply system with a combination of voltage detection circuits, first and second power supply circuits, and active cell balancing circuits, where the second power supply circuit, a switching-type stepdown DC/DC converter, is used for high-efficiency power supply to voltage detection and active balancing, while the first power supply circuit, a linear DC/DC converter, is used for passive balancing, minimizing component complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If passive equalization method is used, then equalization process can be executed with simple structure, but power efficiency deteriorates due to energy loss in discharge resistance
Solution Approach 1:
The patent segments the equalization system into multiple independent balancing circuits, each handling a subset of cells. This allows parallel processing of equalization tasks, reducing overall energy loss while maintaining structural simplicity through modular design.
Solution Approach 2:
The patent dynamically changes the resistance values in balancing circuits based on cell voltage differences. By adjusting resistance parameters in real-time, the system optimizes power efficiency during equalization while keeping the overall structure simple and manageable.
2Loss of energy
If active equalization method is used, then power efficiency is improved by charging cells selectively, but device complexity increases due to required charge circuits
Solution Approach 1:
The patent designs balancing circuits that can function in both active charging and passive discharging modes. Each circuit contains switching elements that enable it to operate as a charge circuit when needed, eliminating the need for separate dedicated charge circuits and reducing overall system complexity.
Solution Approach 2:
The patent employs dynamic switching mechanisms that allow balancing circuits to transition between different operational modes (active charging, passive discharging, standby) based on real-time cell voltage conditions. This dynamic adaptability enables high power efficiency without requiring permanently active complex charge circuits for all cells.
3Ease of operation
If discharge resistance is connected to each cell for passive equalization, then equalization can be performed, but heat generation occurs in the discharge resistance
Solution Approach 1:
The patent introduces switching elements and control circuits as intermediaries between the cells and discharge resistances. These intermediaries enable precise control over when and how current flows through resistances, allowing equalization to proceed while minimizing unnecessary heat generation through intelligent current management.
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 improves power efficiency by reducing energy loss and component complexity during equalization processes in series-connected cells, balancing voltage and capacity effectively.
Implementation Method 1
a plurality of voltage detection circuits connected respectively to the plurality of series cell groups, the voltage detection circuits each detecting a voltage of each of the plurality of cells included in a subject series cell group
Implementation Method 2
a plurality of first power supply circuits connected respectively to the plurality of series cell groups, each of the first power supply circuits reducing a voltage across both ends of the subject series cell group and supplying power to a subject voltage detection circuit
Implementation Method 3
a plurality of active cell balancing circuits connected respectively to the plurality of series cell groups, the active cell balancing circuits each being configured to selectively charge any one of the plurality of cells included in the subject series cell group, using a voltage across both ends of the subject series cell group
Implementation Method 4
a plurality of second power supply circuits connected respectively to the plurality of series cell groups, each of the second power supply circuits reducing a voltage across both ends of the subject series cell group and supplying power to a subject active cell balancing circuit
Data Source
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AI summary
To improve power efficiency while suppressing complication of a component structure in execution of an equalization process between a plurality of cells connected in series, power supply system (1) is provided. In power supply system (1), control circuit (50) performs active balancing between a plurality of cells (E1 to E5, E6 o E 10, E11 to E 15) included in each of a plurality of series cell groups (M1 to M3), using a plurality of active cell balancing circuits (14, 24, 34), and performs passive balancing between the plurality of series cell groups (M1 to M3). Voltage detection circuit (13, 23, 33) connected to a series cell group being undergoing the passive balancing and consuming power is supplied with power from first power supply circuit (11, 21, 31). Voltage detection circuit (13, 23, 33) connected to series cell group (M1 to M3) being undergoing active cell balancing by active cell balancing circuit (14, 24, 34) is supplied with power from second power supply circuit (12, 22, 32) higher in efficiency than first power supply circuit (11, 21, 31).