Parallel Battery Pack Switching via Host Control
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Solution Overview
Problem
The existing power storage systems with parallel secondary battery packs face limitations in flexible operation due to the need for voltage differences to be within a predetermined range, restricting the ability to switch between battery packs with varying capacities and potentially leading to overcurrent or abnormal heat issues.
Innovation Solution
The system incorporates a host system that controls two or more secondary battery packs connected in parallel, using battery detectors, insulated communication, discharge and charge switches, and a constant-current circuit to manage current flow and voltage differences, allowing safe switching between packs by limiting discharge current and controlling charging and discharging paths.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the voltage difference of the storage element row is strictly controlled to be within a predetermined range before connecting to load, then overcurrent and abnormal heat can be prevented, but the operational flexibility and freedom in connecting secondary battery packs is reduced
Solution Approach 1:
The system performs preliminary actions by controlling the charging and discharging paths before connecting the storage element row to the load. The control unit adjusts the charging path of the first storage element row and the discharging path of the second storage element row in advance to equalize voltage differences, ensuring safe connection while maintaining operational flexibility.
Solution Approach 2:
The system dynamically switches between different operating modes (charging path control, discharging path control, and connection control) based on real-time voltage differences and operational requirements. This dynamic approach allows the system to adaptively manage voltage equalization while maintaining flexibility in battery pack connections.
2Reliability
If the charging path and discharging path are controlled to manage voltage differences, then current flow safety is improved, but the system complexity increases
Solution Approach 1:
The control unit serves multiple functions by integrating voltage monitoring, charging path control, discharging path control, and connection management into a single controller. This multi-functional approach improves current flow safety while minimizing the increase in system complexity through functional integration.
Data Source
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AI summary
A power storage system has a plurality of secondary battery packs and a host device. The secondary battery packs each have: secondary batteries; a charge switch means that turns a charging path to the secondary batteries ON and OFF; a discharge switch means that turns a discharging path from the secondary battery ON and OFF; and a current-limiting means that causes the secondary battery to discharge while limiting the current to, or below, a fixed value. When switching from the secondary battery pack connected to the input/output terminals of the system to a first secondary battery pack in which voltage is higher than in the second secondary battery pack, the host device causes the charge switch means of the second secondary battery pack to turn OFF the charging path while in a state in which the current limiting means of the first secondary battery pack will cause a discharge operation to begin while limiting the flow of current.