Second-Use Li-Ion Battery Load Sharing by SoH-Based Discharge Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Used batteries from electric vehicles (EVs) face challenges in second-use applications due to varying sizes, shapes, performance characteristics, and degradation trajectories, leading to inefficient use and short lifespan, while recycling is costly and environmentally unfriendly.
Innovation Solution
A battery management system (BMS) integrates first and second-use batteries, managing their state of health (SoH) and setting discharge limits to extend their life, and uses electromechanical generators efficiently to meet load demands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If second use batteries are used in power generation systems, then cost is reduced and environmental impact is minimized, but battery lifespan is shortened and reliability deteriorates due to varying degradation trajectories
Solution Approach 1:
The patent segments the battery fleet into multiple groups based on their state of health (SoH) and degradation characteristics. Each segment is managed separately with customized discharge limits and operational parameters, allowing the system to extract maximum value from each battery's remaining capacity while preventing premature failure. This segmentation enables heterogeneous batteries with different degradation trajectories to be effectively utilized together.
Solution Approach 2:
The system dynamically adjusts operational parameters including discharge limits, charge rates, and operational thresholds based on each battery's real-time state of health and degradation trajectory. By continuously monitoring and adapting these parameters, the system optimizes the balance between utilization (cost reduction) and battery life extension (reliability maintenance) for second use batteries.
2Duration of action of stationary object
If discharge limits are set for second use batteries, then battery lifespan is extended, but power output is reduced
Solution Approach 1:
The patent implements dynamic discharge limits that adjust in real-time based on battery state of health, ambient conditions, and system demands. Rather than applying static restrictions, the system continuously optimizes discharge parameters to maximize power output within safe operational boundaries, thereby extending battery lifespan without unnecessarily compromising power delivery capability.
Solution Approach 2:
The system employs a universal control framework that manages multiple batteries with different capacities, degradation states, and performance characteristics through a unified set of adaptive algorithms. This multi-functional approach allows the same control logic to optimize both power output and lifespan extension across heterogeneous battery populations.
3Adaptability or versatility
If batteries with different degradation trajectories are used, then system adaptability is improved, but system complexity increases due to varying performance characteristics
Solution Approach 1:
The patent incorporates continuous feedback mechanisms that monitor each battery's state of health, performance metrics, and degradation trajectory. This real-time data feeds into the control system, which automatically adjusts operational parameters and discharge limits for each battery. The feedback loop simplifies management of heterogeneous batteries by enabling autonomous adaptation rather than requiring complex manual configuration.
Solution Approach 2:
The system manages complexity by dynamically changing operational parameters based on observed degradation trajectories. Rather than designing for the worst-case scenario or creating complex static rules, the system adapts parameters in response to actual battery behavior, simplifying the control architecture while maintaining high adaptability to varying performance characteristics.
Data Source
Figure 1
Figure 1A
Figure 2
AI summary
A method of managing second use batteries incudes communicating an external load demand to battery management modules (BMMs) of first use batteries and second use batteries; communicating, by each of the BMMs, the state of health (SoH) of the respective first or second use battery to the other BMMs; by the BMMs of the first use batteries with highest SoH, engaging the first use batteries to meet the external load demand, wherein the highest SoH is determined by the BMMs by ranking the SoH of each battery relative to the other batteries; and by the BMMs of the second use batteries, setting a discharge limit for each of the second use batteries based on the SoH of the respective second use battery, and controlling the second use batteries to supply currents not to exceed the discharge limits of the respective second use batteries to load-share with the first use batteries.