Multi-cell Battery Charging System Voltage Synchronization
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Solution Overview
Problem
Existing multi-cell battery pack charging systems reduce battery life and incur energy losses due to repeated charge/discharge cycles and inefficient charge balancing methods that move charge within cells, causing over or under charging.
Innovation Solution
A multi-cell battery pack charging system that adjusts charging current for each cell to synchronize voltage, allowing the pack to be charged as a whole without charge shuttling or resistive/inductive balancing, using multiple power supplies and a microcontroller to manage charging currents based on voltage differences between cells.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If charge balancing methods (resistive, capacitive, or inductive) are used to equalize battery cell voltages, then charge balance is achieved, but battery life is reduced due to repeated charge/discharge cycles
Solution Approach 1:
The charging system is segmented into multiple independent power supplies, each dedicated to charging a specific battery cell. This allows each cell to be charged independently without requiring charge shuttling between cells, thereby eliminating repeated charge/discharge cycles and extending battery life while maintaining effective charge balancing.
2Reliability
If charge is moved from higher voltage cells to lower voltage cells through balancing circuits, then voltage equalization is achieved, but energy losses occur due to internal resistance
Solution Approach 1:
Instead of moving charge from higher voltage cells to lower voltage cells (the conventional approach), the invention inverts the approach by providing independent power supplies to each cell that can directly supply charging current. This eliminates the need for charge shuttling and the associated energy losses from internal resistance, while still achieving voltage equalization across all cells.
Data Source
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AI summary
A multi-cell battery pack charging system adjusts each battery cell's charging current to synchronize the completion of charge. The battery pack is charged as a whole, and need only be charged once, and without requiring charge shuttling, resistive charge balancing or inductive charge dumping. Charging current to each battery cell is based on voltage matching of the battery cells being charged, lower voltage battery cells being given more charge current until there is a voltage match to the other series connected battery cells. Additional charge may be given to higher capacity cells of the battery pack during the voltage matching and charging process.