Battery Charging Control Switching Series Parallel Configuration
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Solution Overview
Problem
In wireless charging systems, the impedance of secondary batteries fluctuates significantly as they charge, leading to reduced charging efficiency due to magnetic coupling between coils, especially when batteries are near full charge, causing a decrease in transmission efficiency.
Innovation Solution
A charging control device with a switching unit that can switch the connection state of battery modules from series to parallel configuration based on the state of charge, reducing impedance and maintaining efficient charging by adjusting the current command value accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If constant voltage charging is performed when SOC is large, then charging voltage is maintained, but charging efficiency decreases due to large impedance
Solution Approach 1:
The patent dynamically switches the connection configuration of battery modules from series to parallel based on SOC thresholds. When SOC reaches a predetermined threshold during constant voltage charging, the system transitions from series connection (high voltage, low current) to parallel connection (low voltage, high current), maintaining optimal charging efficiency while adapting to changing battery impedance characteristics
Solution Approach 2:
The patent changes the electrical connection parameters of battery modules by switching between series and parallel configurations. This parameter change allows the system to maintain appropriate current levels and impedance matching with the power reception coil, preventing efficiency loss that would occur with fixed series connection during constant voltage charging
2Stress or pressure
If series connection is maintained for all battery modules, then charging voltage is sufficient, but impedance becomes very large near full charge reducing transmission efficiency
Solution Approach 1:
The system dynamically reconfigures battery module connections from series to parallel based on real-time SOC monitoring. This dynamic adaptation ensures that during constant voltage charging when impedance naturally increases, the parallel connection reduces overall impedance to maintain efficient power transfer, while series connection provides sufficient voltage during constant current charging phases
3Productivity
If parallel connection is used from the beginning, then impedance is low, but charging voltage is insufficient for proper charging
Solution Approach 1:
The system initially connects battery modules in series configuration to provide sufficient charging voltage during the constant current charging phase. When SOC reaches a predetermined threshold, the system then switches to parallel connection to reduce impedance and maintain efficiency during constant voltage charging, ensuring both voltage and efficiency requirements are met at appropriate charging stages
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 solution effectively suppresses the reduction in charging efficiency by maintaining optimal impedance levels throughout the charging process, ensuring consistent and efficient power transfer.
Implementation Method 1
a wireless charging system in which electric power is transmitted from a coil (power transmission coil) in a power transmission pad to a coil (power reception coil) in a power reception pad using a magnetic field resonance method
Data Source
AI summary
A charging control device includes a switching unit configured to be capable of switching a connection state of a battery unit including a plurality of battery modules whose number is N×M; and a controller configured to control the switching unit, wherein the controller causes the switching unit to switch the connection state from a first state in which all the battery modules are connected in series to a second state in which N groups each including M battery modules connected in series are connected in parallel when a power storage amount of the battery unit becomes equal to or larger than a first connection switching value in a first charging method in which a current supplied to each of the plurality of battery modules decreases as the power storage amount increases.