Cell Balancing System Dual Voltage Source Switching
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Solution Overview
Problem
Existing cell balancing technologies either consume battery voltage or take a long time to balance, leading to reduced battery performance and lifespan due to voltage imbalances in lithium-ion batteries.
Innovation Solution
A cell balancing system with a battery management system (BMS) that switches between a pack charging voltage and a cell balancing voltage using a microcontroller unit (MCU) and circuit switching unit to apply the balancing voltage only to cells requiring it, allowing for rapid and efficient balancing without consuming battery voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If passive cell balancing scheme is used to reduce voltage difference by consuming voltage as heat energy, then cell balancing speed is improved, but battery voltage is continuously consumed and internal temperature is raised
Solution Approach 1:
The patent introduces a dual voltage source system where a pack charging voltage source and a cell balancing voltage source work together. The pack charging voltage source provides high voltage for rapid balancing, while the cell balancing voltage source provides precise low voltage for fine-tuning. This intermediary approach allows the system to achieve both fast balancing and energy efficiency by switching between or combining the two voltage sources based on the balancing needs.
2Loss of energy
If active cell balancing scheme is used to move voltage between cells using energy storage elements, then energy consumption is reduced, but cell balancing time becomes long
Solution Approach 1:
The patent segments the cell balancing process into two distinct phases handled by different voltage sources. The pack charging voltage source handles the initial high-voltage differential through rapid charging of lower-voltage cells, while the cell balancing voltage source handles the final precise voltage equalization. This segmentation allows the system to combine the speed advantage of passive balancing with the energy efficiency of active balancing, avoiding the long balancing times of pure active schemes.
3Speed
If cell balancing is performed by applying high voltage across resistor to consume voltage difference, then balancing is achieved quickly in one direction, but battery output is reduced and charging cycle is shortened
Solution Approach 1:
The patent implements a dynamic cell balancing system that adapts the balancing approach based on real-time voltage differences and charging conditions. The control unit monitors cell voltages and dynamically switches between the pack charging voltage source and cell balancing voltage source, adjusting the balancing current and duration. This dynamic control allows the system to perform rapid balancing when needed while minimizing voltage consumption and maintaining high charging efficiency throughout the charging cycle.
Data Source
AI summary
The present invention relates to a cell balancing system and method, and more particularly, to a cell balancing system and method capable of supplying a charging voltage through two separately configured charging voltage sources and stably performing cell balancing by supplying a proper charging voltage to a corresponding cell through an individually configured switch in each cell, when the cell balancing is necessary.