Battery Control Circuit Equalizing SOC During Idle Periods
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Solution Overview
Problem
Battery devices in electric vehicles face energy loss due to SOC fluctuations among connected batteries, particularly when batteries with large capacities are involved, as existing voltage equalization methods are limited and inefficient, especially during non-operational periods.
Innovation Solution
A battery control circuit that operates after the battery device stops, using a management unit to monitor and discharge batteries with high SOC, transitioning to a power-saving mode once the intended voltage or SOC is reached, thereby reducing energy loss with a simple process and minimal commands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If voltage equalization is performed only during battery device operation, then the control process remains simple, but the equalization time becomes excessively long for batteries with large capacity differences
Solution Approach 1:
The patent applies preliminary action by performing voltage equalization during the stop period before the battery device is needed again. The control circuit calculates the required equalization time in advance and executes discharge control of high-SOC batteries during idle time, ensuring batteries are properly equalized before the next operational period begins. This prevents excessive equalization time delays from affecting device operation.
2Reliability
If the battery control means operates continuously to perform voltage equalization, then equalization effectiveness is maximized, but energy consumption increases
Solution Approach 1:
The patent implements periodic action by operating the battery control means only during the stop period of the battery device, rather than continuously. The control circuit activates during idle time to perform voltage equalization through bypass switches, then enters a low-power state during operational periods. This periodic operation maintains equalization effectiveness while significantly reducing overall energy consumption of the control system.
3Device complexity
If a bypass switch is used for voltage equalization, then the equalization circuit is simple, but the method is limited by the degree of voltage fluctuation and cannot handle large capacity differences effectively
Solution Approach 1:
The patent enhances the simple bypass switch circuit by calculating the required equalization time in advance based on battery capacity differences and voltage fluctuations. The control circuit determines the discharge duration needed to equalize batteries with large capacity variations, then executes this pre-calculated equalization plan during the stop period. This preliminary calculation approach enables the simple circuit to handle large capacity differences effectively.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively suppresses energy loss in battery units by allowing continuous voltage and SOC equalization, even when the device is not in operation, thereby extending battery life and improving overall energy efficiency.
Implementation Method 1
a voltage equalization circuit made up of a bypass resistor and a bypass switch connected in parallel to the battery
Implementation Method 2
the battery control means controls the bypass switch of the equalization circuit based on a voltage fluctuation amount. That is, the method forcibly discharges a battery having a high voltage to equalize voltages
Data Source
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AI summary
In a battery device including a battery pack in which a plurality of cells are connected in series, there are provided a battery control circuit or a battery device capable of eliminating a fluctuation in the voltage or charged state which can occur between the cells, or preventing the cells from being maintained in an over-charged state for a long period. A plurality of cell groups 112 each including a plurality of cells 111 are connected in series to form a battery pack 110. Cell control means 121 provided to the respective cell groups operate with electricity supplied from the cell groups allocated thereto so as to monitor and control the state of the cells of the cell group. Battery pack control means 150 controls the cell control means based on information from the plurality of cell control means. When there is a cell group of which the charged state is higher than a predetermined charged state, the battery pack control means allows operation of the cell control means that monitors the cell group having the high charged state to be continued when charging and discharge of the battery pack stop to thereby discharge the cells to decrease the charged state.