Battery Cell Voltage Balancing via Dynamic Current Reduction
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Solution Overview
Problem
Existing power storage devices take a long time to charge fully due to voltage differences among sub-modules, leading to repeated enabling and disabling of charging, which generates noise and prolongs the charging process.
Innovation Solution
A power storage device with a control unit that uses a cell balance discharging circuit to gradually lower the charging current for cells reaching a predetermined voltage, enabling cell balancing only for cells exceeding a certain voltage threshold, thereby reducing voltage spikes and noise, and ensuring all cells reach a full charge efficiently.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If charging is repeatedly enabled and disabled to perform cell balance adjustment, then cell voltage equality is improved, but charging time is prolonged and noise is generated
Solution Approach 1:
The patent implements periodic cell balance adjustment by monitoring cell voltages during charging and temporarily suspending charging only when voltage differences exceed a threshold, rather than continuously enabling/disabling charging. This periodic intervention maintains cell voltage equality while minimizing charging time extension and reducing noise generation from frequent switching.
Solution Approach 2:
The patent changes the voltage threshold parameter dynamically based on charging state and cell characteristics. By adjusting the threshold for triggering balance adjustment, the system optimizes between maintaining cell voltage equality and minimizing charging time penalty, thereby reducing unnecessary charging suspensions and associated noise.
2Manufacturing precision
If charging is repeatedly enabled and disabled to perform cell balance adjustment, then cell voltage equality is improved, but noise generation increases
Solution Approach 1:
The system performs cell balance adjustment periodically based on voltage threshold monitoring rather than through continuous enabling/disabling of charging. This reduces the frequency of charging suspensions and resume operations, thereby minimizing noise generation from repeated switching while still maintaining cell voltage equality.
Solution Approach 2:
The patent implements feedback control by continuously monitoring cell voltages and only suspending charging when the voltage difference exceeds a predetermined threshold. This feedback mechanism prevents unnecessary charging suspensions and associated noise generation while ensuring cell balance is maintained within acceptable limits.
3Manufacturing precision
If cell balance adjustment is performed by temporarily stopping charging and discharging, then voltage difference between cells is reduced, but charging efficiency decreases
Solution Approach 1:
The patent implements periodic cell balance adjustment by monitoring cell voltages during charging and temporarily suspending charging only when voltage differences exceed a threshold, rather than continuously enabling and disabling charging. This periodic intervention maintains cell voltage equality while minimizing charging time extension and reducing noise generation from frequent switching.
Solution Approach 2:
The patent applies partial balance adjustment by only intervening when voltage differences exceed a predetermined threshold, rather than continuously adjusting all cells. This selective approach maintains sufficient cell voltage equality while minimizing the impact on charging efficiency and overall charging time.
Data Source
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AI summary
A power storage device includes: power storage units each including at least one battery, the power storage units being connected in series; cell balance units connected in parallel to the respective power storage units via switches; and a control unit that performs control to charge the power storage units with a first constant current value, and, when the power storage unit having the highest voltage among the power storage units reaches a first potential, connect the corresponding one of the cell balance units to the power storage unit having the highest voltage, and switch the charging current to a second constant current value that is smaller than the first constant current value.