All-solid-state battery recovery charging via micro short-circuit
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Solution Overview
Problem
Existing secondary battery systems with multiple unit cells connected in series face a reduction in available electricity due to variations in state of charge, and existing solutions like water generation reactions are not applicable to all-solid-state lithium batteries or systems with multiple unit cells.
Innovation Solution
A secondary battery system and control method that performs recovery charging by generating a micro short-circuit in at least one unit cell using a higher recovery charging current than normal, with adaptive voltage control to stabilize the short-circuit, and includes components for determining short-circuit generation and actual discharge capacity to minimize state of charge variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple unit cells are connected in series to achieve high voltage charging and discharging, then power output is improved, but variation in state of charge between unit cells increases causing reduction in available electricity
Solution Approach 1:
The patent applies preliminary action by performing recovery charging before the battery system reaches its operational state. By charging at a higher current than normal operation allows, the system proactively equalizes state of charge variations between unit cells in advance, preventing performance degradation before it occurs. This preventive approach ensures all unit cells start at similar charge levels, maximizing available electricity for the upcoming operational cycle.
Solution Approach 2:
The patent utilizes parameter changes by temporarily altering the charging current parameter during recovery charging. The charging current is increased to a higher value than normal operation parameters, which accelerates the equalization process. This parameter modification allows the system to quickly address state of charge variations without requiring structural changes to the battery configuration.
2Productivity
If recovery charging is performed at a higher current value to minimize state of charge variations, then productivity is improved, but the risk of generating harmful effects such as overheating or degradation increases
Solution Approach 1:
The patent implements periodic action by alternating between normal charging operations and recovery charging cycles. Instead of continuously charging at high current, the system periodically interrupts normal operation to perform recovery charging when state of charge variations are detected. This periodic approach allows the battery system to dissipate heat and recover between high-current pulses, preventing cumulative thermal damage while maintaining charging efficiency over time.
Solution Approach 2:
The patent applies feedback by continuously monitoring the state of charge of individual unit cells and using this information to determine when recovery charging is needed. The system measures voltage or other parameters of each unit cell, compares them to detect variations, and only initiates high-current recovery charging when necessary. This feedback mechanism ensures high-current charging is applied selectively rather than continuously, reducing the risk of overheating and degradation while maintaining productivity when needed.
Data Source
AI summary
A secondary battery system and a secondary battery control method, wherein the system and the method include a plurality of unit cells connected in series, and a recovery charging controller that performs recovery charging of charging the plurality of unit cells while generating a micro short-circuit in at least one of the plurality of unit cells by charging the plurality of unit cells at a predetermined recovery charging current value which is higher than a upper limit current value during normal charging, wherein the unit cells are all-solid-state lithium secondary battery unit cells.