EV Drivetrain Battery Switching for 400V-to-800V Fast Charging
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current high-voltage power supply systems for electric vehicles require costly and power-limiting DC/DC converters to charge at 800V using conventional 400V charging stations, leading to increased complexity and longer charging times, while conventional CC-CV charging can negatively impact battery lifetime.
Innovation Solution
A power supply system with two high-voltage battery units connected in series, using high-power switching semiconductor devices and an electronic control system to alternate high-voltage DC charging at frequencies between 100-10000 Hz, eliminating the need for a 400/800V DC/DC converter and implementing pulse charging for improved battery health.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a 400V to 800V DC/DC converter is used to enable charging at 800V from conventional 400V charging stations, then charging voltage compatibility is improved, but device complexity and cost increase
Solution Approach 1:
The battery system is segmented into two separate 400V battery units (first and second battery units) that can be charged independently. During charging, the circuit arrangement selectively connects only one battery unit to the charging source at a time, avoiding the need for a complex 400V to 800V DC/DC converter while maintaining compatibility with conventional charging stations
Solution Approach 2:
The system dynamically switches between different battery units during charging operations. The circuit arrangement alternates connection between the first and second battery units at frequencies of at least 100 Hz, enabling adaptive charging that responds to battery state, temperature, and charging power availability without requiring fixed complex conversion hardware
2Adaptability or versatility
If a 400V to 800V DC/DC converter is used to enable charging at 800V, then charging voltage compatibility is improved, but cost increases
Solution Approach 1:
The battery system is segmented into two separate 400V battery units (first and second battery units) that can be charged independently. During charging, the circuit arrangement selectively connects only one battery unit to the charging source at a time, avoiding the need for a complex 400V to 800V DC/DC converter while maintaining compatibility with conventional charging stations
Solution Approach 2:
The battery units serve themselves during charging by alternately accepting charge from the same charging source. The system uses its own internal switching capability to manage the charging alternation between units, eliminating the need for expensive external conversion equipment and reducing overall system cost
3Ease of operation
If conventional CC-CV charging is used, then charging simplicity is maintained, but battery lifetime deteriorates due to dendrite formation
Solution Approach 1:
The system implements periodic action by alternating charging between the first and second battery units at frequencies of at least 100 Hz. This pulsed charging approach prevents continuous high-current charging that causes dendrite formation, while the rapid alternation maintains effective charging speed and simplicity of operation
Solution Approach 2:
The battery system is segmented into two separate 400V battery units (first and second battery units) that can be charged independently. During charging, the circuit arrangement selectively connects only one battery unit to the charging source at a time, avoiding the need for a complex 400V to 800V DC/DC converter while maintaining compatibility with conventional charging stations
4Power
If high-voltage DC is supplied from series-connected battery units, then power supply voltage is improved to enable high power output, but device complexity increases due to switching requirements
Solution Approach 1:
The system dynamically switches between different battery units during charging operations. The circuit arrangement alternates connection between the first and second battery units at frequencies of at least 100 Hz, enabling adaptive charging that responds to battery state, temperature, and charging power availability without requiring fixed complex conversion hardware
Solution Approach 2:
The circuit arrangement merges the functionality of charging control and power supply mode switching into a single integrated system. The same circuit that alternates battery units during charging also enables series connection for high-voltage DC output during power supply mode, reducing overall device complexity despite the dynamic switching requirements
Data Source
AI summary
A power supply system for an electric vehicle drivetrain includes series connected first and second high-voltage battery units, a circuit arrangement having high-power switching semiconductor devices connected to the battery units, and an electronic control system. During a charging mode, the control system controls the semiconductor devices to route high-voltage DC from a vehicle external charging source alternatingly to the battery units. During a power supply mode, the control system controls the operation of the semiconductor devices to supply high-voltage DC from both the battery units for driving a vehicle electrical traction machine of the electric vehicle drivetrain, wherein the supplied high-voltage DC has a voltage level corresponding to an accumulated voltage level of the series connected battery units.