EV Charging Relay Control for Commercial Battery Voltage Balance
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Solution Overview
Problem
Commercial electric vehicles require high-voltage charging systems, which are not compatible with existing passenger vehicle chargers, leading to inefficiencies and safety concerns, as well as the need for expensive chargers.
Innovation Solution
An apparatus that includes a switch unit with relays and a control unit to connect multiple passenger vehicle chargers in series, allowing for the charging of commercial electric vehicle batteries using standard passenger vehicle chargers, while maintaining voltage balance and safety.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high voltage of 600 V or more is used in commercial electric vehicles, then the voltage system requirements are met, but it is impossible to use existing passenger vehicle chargers and expensive chargers are required
Solution Approach 1:
The high-voltage battery system is divided into multiple battery packs (first battery and second battery), each capable of being charged independently by separate chargers. This segmentation allows the use of standard passenger vehicle chargers (360V) to charge each battery pack, while the batteries can be connected in series to provide the required 600V or more for commercial electric vehicle operation.
Solution Approach 2:
The battery system is designed to serve multiple functions: individual batteries can be charged by standard passenger vehicle chargers, while the combined system provides high-voltage output for commercial electric vehicle operation. The switch unit enables the system to adapt between different charging configurations, making it universally compatible with both passenger and commercial charging standards.
2Power
If high voltage of 600 V or more is used, then voltage system requirements are met, but charger cost increases significantly
Solution Approach 1:
The system divides the high-voltage requirement into multiple lower-voltage battery packs that can be charged by inexpensive standard chargers. Instead of requiring one expensive 600V charger, the system uses multiple affordable 360V chargers that can charge each battery pack independently, significantly reducing overall charging system cost.
3Power
If multiple batteries are connected in series to achieve high voltage, then voltage requirements are met, but voltage balance between batteries becomes difficult to control
Solution Approach 1:
The control unit continuously monitors the charging state and voltage levels of each battery pack, and dynamically controls the switch unit to adjust the charging distribution. This feedback mechanism ensures that voltage balance is maintained between series-connected batteries, preventing overcharging or undercharging of individual packs while achieving the required high-voltage output.
Data Source
AI summary
An apparatus for controlling charging of an electric vehicle includes a switch unit including a first relay and second relays, wherein the first relay is arranged on an electric line through which a first battery is connected in series to a second battery. The first and second batteries supply driving power of the electric vehicle. The plurality of second relays is arranged on charging lines through which charging power is supplied to the first battery and the second battery, respectively. Further, a control unit configured to control the first relay and the plurality of second relays such that the first relay is turned off and the plurality of second relays is turned on to supply the charging power of a charger connected to a charging terminal to the first battery and the second battery, respectively, when the first battery and the second battery are charged.