Battery Cell Multiplexing for Dendrite-Safe Power Delivery
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Solution Overview
Problem
Conventional electrochemical cell management systems result in poor longevity and performance due to short cycle life and safety hazards from dendrite formation, particularly in lithium-containing cells, where charge and discharge rates are not optimally managed.
Innovation Solution
A multiplexing system that includes multiple electrochemical cell sets, a multiplexing switch apparatus, and a controller to compare power demand to a threshold, selectively discharging cells when demand is below the threshold, thereby improving cycle life and safety by managing charge and discharge rates.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional electrochemical cell management systems are used, then the system structure is simple, but the cycle life and safety are poor due to dendrite formation
Solution Approach 1:
The battery system is divided into multiple electrochemical cell sets (first set, second set, third set) that can be independently managed and discharged. The multiplexing switch apparatus segments the discharge paths, allowing selective connection of different cell sets to the output based on power demand, thereby reducing dendrite formation in individual cells while maintaining overall system functionality.
Solution Approach 2:
The system dynamically adjusts the discharge configuration based on real-time power demand. The controller compares power demand to a threshold and switches between different discharge modes (single cell set discharge vs. multiple cell sets discharge) using the multiplexing switch apparatus, optimizing cycle life and safety adaptively without requiring a complex fixed structure.
2Power
If all cells are discharged simultaneously to meet high power demand, then power delivery is sufficient, but dendrite formation increases and safety decreases
Solution Approach 1:
The system implements periodic switching between different discharge configurations. The multiplexing switch apparatus alternates between connecting single cell sets and multiple cell sets in parallel based on whether power demand exceeds the threshold, providing periodic variation in discharge patterns that reduces cumulative dendrite formation while maintaining adequate power delivery over time.
Solution Approach 2:
The system changes the discharge parameter (number of active cell sets) based on power demand conditions. When power demand is below the threshold, fewer cell sets are activated, reducing discharge rate and dendrite formation risk. When power demand exceeds the threshold, more cell sets are activated to meet the higher power requirement, dynamically adjusting the discharge parameter to balance power delivery and safety.
3Power
If the discharge rate is increased to meet power demand, then power delivery improves, but cycle life decreases due to accelerated degradation
Solution Approach 1:
The system dynamically adjusts the discharge rate by switching between different cell set configurations. When power demand is low, the discharge rate is reduced by activating fewer cell sets, preserving cycle life. When power demand is high, the discharge rate is increased by activating more cell sets in parallel, meeting power requirements while distributing the stress across multiple cells to mitigate degradation.
Data Source
AI summary
Multiplexing systems for batteries of electrochemical cells and associated methods are generally described. Multiplexing systems may be used to improve certain properties of electrochemical cells, such as cycle life and/or safety, during cycling of the battery, according to some embodiments. For example, in some embodiments improvements in electrochemical cell and/or battery performance are provided that are associated with management of charging and discharging of electrochemical cells by the multiplexing system.