EV Charging Circuit Topology for 400V/800V Battery Reconfiguration
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Solution Overview
Problem
Existing charging systems for electric vehicles with 800V batteries are not compatible with standard 400V fast-chargers, requiring a 400/800V-booster DC/DC voltage converter, which increases costs and complexity.
Innovation Solution
A charging system with a DC/DC-converter and circuit breakers that allows 400V and 800V batteries to adapt their nominal voltage to match charging inlet voltage, using two 400V-battery units that can be connected in series or parallel, and a DC/DC-converter to convert voltages as needed, ensuring compatibility with both 400V and 800V charging stations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a 400/800V-booster DC/DC voltage converter is used to enable 400V fast-chargers with an 800V-battery electric vehicle, then compatibility with 400V charging stations is achieved, but system cost and complexity increase
Solution Approach 1:
The battery system is segmented into two separate 400V battery units that can be independently connected in series to form an 800V configuration or in parallel to maintain 400V operation. This segmentation eliminates the need for complex DC/DC converters by allowing direct voltage configuration through circuit breaker arrangements.
Solution Approach 2:
The system dynamically reconfigures the battery units based on charging requirements. Circuit breakers selectively connect the battery units in series or parallel configurations, enabling the system to adapt its voltage output dynamically without requiring additional conversion equipment.
2Productivity
If an 800V-battery is used to provide higher power density and reduced charging time, then charging performance improves, but compatibility with existing 400V charging infrastructure is lost
Solution Approach 1:
The battery system is designed with universal functionality to operate in multiple voltage configurations. The same battery units can serve both 400V and 800V operating modes, allowing the vehicle to charge at high speed when 800V stations are available while maintaining compatibility with the broader 400V charging infrastructure.
3Power
If two 400V-battery units are connected in series to form an 800V-battery, then power density and charging speed improve, but the system cannot operate at 400V when needed
Solution Approach 1:
The system employs dynamic reconfiguration through circuit breakers that can selectively connect the two 400V battery units in series for 800V operation or in parallel for 400V operation. This dynamic switching capability allows the system to optimize power density when needed while maintaining voltage adaptability for different operating conditions and charging scenarios.
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
Enables efficient charging of 400V and 800V batteries without increasing charging time, reduces system costs, and allows use in countries with voltage restrictions, while maintaining isolation and balancing battery state-of-charge.
Implementation Method 1
The DC/DC converter is configured to convert the charging inlet voltage into the nominal voltage of the at least one auxiliary component, if the charging inlet voltage is different from the nominal voltage of the at least one auxiliary component
Data Source
AI summary
A charging system for charging an electric vehicle battery, including a charging inlet connected to an external direct current (DC) charging station providing a predefined charging inlet voltage, a battery having a nominal voltage of 400V or 800V connected to the charging inlet, the battery including two 400V-battery units, and a voltage outlet, the voltage outlet supplying an output voltage to an auxiliary component connected to the voltage outlet having a nominal voltage corresponding to the nominal voltage of the battery, a DC/DC converter converting the charging inlet voltage into the nominal voltage of the auxiliary component, and at least three circuit breakers being arranged to connect the two 400V-battery units to form a charging circuit having a nominal charging voltage corresponding to the supplied charging inlet voltage and/or to selectively integrate the DC/DC converter into the charging circuit to provide the auxiliary component with the nominal voltage during charging.