Parallel Battery Stack Control for State-of-Charge Balancing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Large batteries with multiple stacks of electrochemical cells face challenges in managing variations in state of charge, capacity, and safety across stacks, which can lead to inefficient operation and potential damage, especially in Lithium-ion batteries prone to overcharging and thermal issues.
Innovation Solution
A method for managing multiple stacks of electrochemical cells by executing a global operating strategy while simultaneously applying a local operating strategy to specific stacks, allowing for individual control of stack operations such as changing power levels, current levels, and state of charge to maintain overall battery health and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a single global operating strategy is applied to all stacks, then overall battery operation is simplified, but variations in state of charge and capacity across stacks cannot be addressed, leading to inefficient operation and potential damage
Solution Approach 1:
The battery management system is segmented into a central controller that executes global operating strategies and individual stack controllers that execute local operating strategies. This segmentation allows each stack to be managed independently according to its specific state of charge and capacity characteristics, while still contributing to the overall battery operation. The segmentation resolves the contradiction by enabling differentiated control without compromising system-wide coordination.
Solution Approach 2:
The system implements local quality by allowing each stack to have its own operating strategy tailored to its specific characteristics (state of charge, capacity, temperature). The local operating strategies are customized based on real-time stack conditions, enabling optimal performance and safety for each individual stack while maintaining contribution to the global battery operation.
2Reliability
If local operating strategies are applied to individual stacks, then variations in state of charge and capacity can be addressed, but system complexity increases due to coordinating multiple strategies
Solution Approach 1:
The system merges the global operating strategy from the central controller with local operating strategies from individual stack controllers into a unified control framework. The central controller coordinates the overall battery operation while stack controllers handle individual stack management. This merging approach reduces complexity by establishing clear hierarchical relationships and communication protocols between different control levels, avoiding the need for completely independent control systems.
Solution Approach 2:
The operating strategies are made dynamic and adaptive, allowing the central controller to adjust global strategies based on real-time feedback from stack controllers, and allowing stack controllers to modify local strategies based on changing stack conditions. This dynamic adjustment capability enables the system to maintain optimal performance while adapting to varying operational requirements, reducing the need for complex static control configurations.
3Quantity of substance
If lithium-ion batteries operate at high energy density, then energy storage capacity is improved, but susceptibility to overcharging, thermal issues, and safety hazards increases
Solution Approach 1:
The battery management system implements continuous feedback monitoring of each stack's state of charge, temperature, and operational parameters. The central controller and stack controllers use this feedback information to adjust operating strategies in real-time, preventing overcharging and thermal runaway conditions. The feedback mechanism enables early detection of potentially harmful conditions and automatic corrective actions, allowing the system to safely operate at high energy density levels.
Solution Approach 2:
The system performs preliminary actions by continuously monitoring stack conditions and predicting potential safety issues before they occur. The local operating strategies include preventive measures such as limiting charge/discharge rates, maintaining appropriate temperature ranges, and preventing overcharging before it can cause damage. This preliminary action approach allows the high energy density batteries to operate safely by addressing potential hazards before they manifest as actual problems.
Data Source
AI summary
A method for managing a plurality of stacks of electrochemical cells, where the plurality of stacks are electrically coupled in parallel in a battery. The method includes (a) operating the plurality of stacks to execute a global operating strategy, (b) controlling one or more first power converters to change operation of one or more first stacks of the plurality of stacks to execute a first local operating strategy of operating the one or more first stacks at one of a constant power and a constant current, and (c) controlling one or more second power converters to change operation of one or more second stacks of the plurality of stacks to compensate for change in operation of the one or more first stacks caused by executing the first local operating strategy, and thereby maintain the global operating strategy of the battery while executing the first local operating strategy.