Multiplexed Battery String Switching for Stable Power Delivery
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Solution Overview
Problem
Conventional battery management systems fail to provide adequate longevity and performance due to poor cycle life and voltage fluctuations, particularly when charge and discharge rates are similar or charge rate exceeds discharge rate, leading to inefficient power delivery and potential circuit damage from in-rush currents.
Innovation Solution
A battery management system with a multiplexing switch apparatus and controller that transitions between discharging strings of cells while maintaining a voltage difference and in-rush current within thresholds, ensuring smooth power delivery and minimizing circuit stress.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If conventional battery management systems discharge cells at similar charge and discharge rates, then the system structure is simple, but the battery cycle life is poor and voltage fluctuations occur
Solution Approach 1:
The battery pack is divided into multiple independent cell strings, each with its own multiplexing switch apparatus. This segmentation allows independent control of charge and discharge operations for each string, enabling the system to achieve better cycle life through selective discharge while maintaining relatively simple overall structure.
Solution Approach 2:
The multiplexing switch apparatus dynamically transitions between connecting different cell strings to the load, adjusting which strings are discharging at any given moment. This dynamic switching enables the system to maintain voltage differences within thresholds and reduce voltage fluctuations, improving battery reliability without requiring complex additional components.
2Reliability
If the charge rate exceeds the discharge rate, then battery longevity is improved, but power delivery efficiency decreases and in-rush currents may damage circuits
Solution Approach 1:
The controller monitors voltage differences between cell strings and predicts when transitions should occur. By preparing for transitions in advance and switching between strings before large voltage differences develop, the system avoids in-rush currents while maintaining efficient power delivery. This preliminary action prevents circuit damage while preserving productivity.
Solution Approach 2:
The multiplexing switch apparatus ensures continuous power delivery by transitioning between cell strings without interruption. When one string's voltage approaches the threshold, the system seamlessly switches to another string, maintaining continuous discharge operation. This continuity preserves power delivery efficiency while the controlled transitions prevent in-rush currents that would damage circuits.
3Productivity
If multiple cell strings are discharged simultaneously, then power delivery is uninterrupted, but voltage fluctuations increase and circuit stress rises
Solution Approach 1:
Instead of discharging all cell strings simultaneously, the system discharges only one or a limited number of strings at a time, keeping the voltage difference between active and inactive strings within a threshold. This partial action approach maintains power delivery continuity while significantly reducing voltage fluctuations and circuit stress compared to simultaneous discharge of all strings.
Data Source
AI summary
Electrochemical cell and battery management systems comprise at least one battery comprising two or more strings of cells, each string of cells comprising two or more cells. The system includes a multiplexing switch apparatus connected to each string of cells and a controller. the controller is used to control various aspects of the charge and/or discharge of the electrochemical cell and/or battery.