Transformer-Based Battery Balancing Device
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Solution Overview
Problem
Secondary batteries connected in series face voltage and charge imbalances due to differences in electrical characteristics and deterioration, leading to reduced usable voltage range, shortened charging and discharging periods, and a shortened lifecycle, which existing balancing methods, especially passive methods, fail to address efficiently.
Innovation Solution
A balancing device and method utilizing a transformer with primary and secondary windings and a switch network to selectively connect terminals, enabling various balancing modes and reducing manufacturing cost and size by using a small number of switching elements, allowing energy transfer between battery cells and modules.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive balancing method is used to balance battery cells, then energy is consumed through resistor to balance energy between battery cells, but this method is inefficient and increases energy loss
Solution Approach 1:
The patent introduces a capacitor as an intermediary energy transfer medium between battery cells. The capacitor temporarily stores energy from cells with higher voltage and releases it to cells with lower voltage, enabling active balancing without direct resistive dissipation. This mediator approach transforms the inefficient passive balancing into an efficient active balancing system.
Solution Approach 2:
The patent changes the balancing approach from passive energy dissipation to active energy transfer by utilizing capacitive energy storage and release. By changing the physical parameter of energy transfer mechanism (from resistive to capacitive), the system achieves efficient balancing while minimizing energy loss.
2Reliability
If conventional balancing methods are used, then balancing function is achieved, but manufacturing cost and size are increased due to large number of switching elements required
Solution Approach 1:
The patent designs a switch network where each switching element serves multiple functions: connecting different battery cells to the capacitor, controlling charge/discharge paths, and enabling various balancing modes. This multi-functionality reduces the total number of switching elements required compared to conventional methods that require dedicated switches for each cell pair.
Solution Approach 2:
The patent merges the balancing function with the existing battery management system architecture by integrating the switch network and capacitor into a unified structure. Multiple balancing operations are combined into a single capacitive energy transfer system, reducing component count and simplifying the overall device complexity.
3Ease of operation
If battery cells are charged and discharged with the same current without balancing, then charging and discharging process is simple, but voltage imbalance and charge imbalance occur between battery cells
Solution Approach 1:
The patent implements a self-service balancing system that automatically detects voltage imbalances between battery cells and activates the capacitor-based balancing circuit when needed. The system monitors cell voltages and autonomously performs balancing operations without requiring external intervention, maintaining both simplicity and reliability.
Solution Approach 2:
The patent incorporates voltage monitoring and feedback control mechanisms that detect voltage differences between battery cells and trigger balancing operations accordingly. The feedback loop ensures that balancing is performed only when necessary, maintaining voltage uniformity while minimizing interference with normal charging and discharging operations.
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 solution achieves effective balancing between battery cells, extending their lifecycle by enabling various balancing modes and current gains, thereby increasing the degree of freedom in algorithm design and reducing manufacturing costs.
Implementation Method 1
a method of using a magnetic element, such as a transformer or an inductor, as an energy transfer medium
Data Source
AI summary
Provided are balancing device and method which can achieve a balancing function between energy storage units connected in series using a small number of switch elements, thereby reducing the manufacturing cost and size and enabling various balancing modes. The balancing device for balancing between a plurality of energy storage units a battery module, in which the energy storage units are connected in series, includes: a transformer; and a switch network comparing a cell switch unit, a polarity switch unit, and au auxiliary switch unit, wherein the auxiliary switch unit includes: a first auxiliary switch unit for connecting a second common node to one terminal of the secondary winding of the transformer; and a second auxiliary switch unit for connecting a first common node to the other terminal of the secondary winding of the transformer.