Transformer Active Cell Balancing for Low-Loss Battery Packs
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Solution Overview
Problem
Existing battery pack technologies face inefficiencies in balancing cell charges, with passive balancing wasting energy as heat and requiring complex control circuitry, while active balancing needs additional circuitry for efficient charge transfer.
Innovation Solution
An active cell balancing circuit using transformers with primary and secondary windings, controlled by PWM controllers, and a balancing controller that adjusts charge based on voltage differences, incorporating reverse and overcurrent protection, and temperature monitoring for efficient charge distribution.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If passive balancing is used to balance cell charges, then charge balancing is achieved, but energy is wasted as heat and control circuitry becomes complex
Solution Approach 1:
The patent introduces a transformer as an intermediary device between battery cells to enable active charge balancing. The transformer couples cells through magnetic coupling, allowing charge transfer without direct electrical connection, thereby reducing energy losses and eliminating the need for complex control circuitry while maintaining reliable charge balancing
2Loss of energy
If active balancing is used to transfer charge efficiently, then energy efficiency is improved, but additional circuitry is required
Solution Approach 1:
The transformer serves as a simple yet effective intermediary that enables efficient charge transfer between battery cells through magnetic coupling. This approach achieves active balancing with minimal additional circuitry, as the transformer inherently provides the necessary coupling without requiring complex control electronics
Solution Approach 2:
The transformer-based active balancing system leverages the natural magnetic coupling properties of transformers to achieve charge transfer. The system uses the inherent characteristics of the transformer and battery cells themselves to perform the balancing function, minimizing the need for additional active control circuitry
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 efficient charge balancing across battery cells without complex control circuitry, enhancing power transfer efficiency and protecting against damage.
Implementation Method 1
a plurality of transformers respectively having a primary winding and a secondary winding, wherein the secondary windings are coupled to the plurality of battery cells
Implementation Method 2
a plurality of transformer controllers respectively coupled to the plurality of transformers to provide input signals to the primary windings, and The transformer controllers may be pulse width modulation (PWM) controllers
Data Source
AI summary
An active cell balancing circuit for a battery pack that includes a plurality of battery cells is provided. The active cell balancing circuit may include a plurality of transformers respectively having a primary winding and a secondary winding, wherein the secondary windings are coupled to the plurality of battery cells, a plurality of transformer controllers respectively coupled to the plurality of transformers to provide input signals to the primary windings, and a balancing controller coupled to the plurality of transformer controllers and the plurality of transformers, to detect a current or voltage at one or more of the primary windings and output control signals to cause the transformer controllers to generate the input signals provided to the primary windings. The balancing controller may selectively output the control signals based on the detected current or voltage to charge one or more of the plurality of battery cells.