Analog Battery Voltage Equalizer Circuit for Li-Polymer Modules
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Solution Overview
Problem
Conventional digital battery equalization controllers are costly, inefficient, and limited in supporting battery modules with more than 7 cells, causing imbalanced power storage and potential damage to Li-Polymer batteries due to inappropriate charging and discharging practices.
Innovation Solution
An analog battery voltage equalizer circuit with a battery voltage detector unit and equalizer unit that conducts equalization current only when a battery cell's voltage exceeds a predetermined equalization voltage, preventing overcharging and minimizing power waste by stopping equalization when all cells reach this voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a digital battery equalization controller with A/D converter is used, then battery voltage equalization can be achieved, but the chip size becomes larger and production cost increases
Solution Approach 1:
The patent replaces the digital A/D converter-based voltage detection system with an analog circuit system. The analog battery voltage detector unit directly compares battery voltages using operational amplifiers and reference voltages, eliminating the need for digital conversion components. This substitution reduces chip size and production cost while maintaining voltage equalization functionality.
Solution Approach 2:
The patent employs simple analog components such as operational amplifiers, resistors, and reference voltage sources instead of expensive digital A/D converters. These analog components are more cost-effective and easier to manufacture, directly addressing the production cost and chip size issues while achieving the same voltage detection and equalization function.
2Measurement precision
If conventional battery equalization circuits discharge batteries with higher voltages until all voltages are equal, then voltage equalization is achieved, but discharging performance deteriorates and batteries may be damaged
Solution Approach 1:
The patent performs voltage equalization proactively during the charging process before the batteries reach full charge, rather than discharging batteries after charging. The analog battery voltage detector unit continuously monitors battery voltages during charging and activates the equalization circuit when voltage differences are detected, preventing overcharge damage while achieving equalization.
Solution Approach 2:
The patent converts the potential harm of voltage imbalance into a benefit by using the voltage difference itself as the trigger signal for equalization. When the detector unit detects that one battery has higher voltage than another, it automatically activates the equalization circuit to balance the voltages, turning the harmful voltage discrepancy into the driving force for correction.
3Adaptability or versatility
If battery modules with more than 7 cells are supported, then versatility is improved, but conventional digital controllers are limited and cannot accommodate larger configurations
Solution Approach 1:
The patent designs the analog battery voltage detector unit with universal applicability to battery modules of any size. The circuit uses modular operational amplifier configurations that can be scaled to detect and equalize voltages across any number of series-connected battery cells, removing the 7-cell limitation of digital controllers. The same basic circuit topology works for 2 cells or dozens of cells.
Data Source
AI summary
A battery voltage equalizer circuit for equalizing battery voltages among a plurality of battery cells in a serial connection is disclosed. The battery voltage equalizer circuit includes a battery voltage equalizer unit having a plurality of equalizer parts, wherein each equalizer part, coupled to a positive terminal and a negative terminal of a corresponding battery cell, is conducted with an equalization current upon a receipt of an equalization signal, and a battery voltage detector unit, coupled to the positive and negative terminals of the plurality of battery cells, generates the equalization signal so as to conduct the battery voltage equalizer unit as long as a voltage of any one of the battery cells reaches an equalization voltage.