Vehicle HV Battery Reconfiguration for 400 V Charging Compatibility
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Solution Overview
Problem
The existing methods for operating motor vehicles with high-voltage electrical systems face inefficiencies and increased costs due to the need to adapt components for high electrical currents during charging, leading to weight and manufacturing cost issues, and inefficient voltage reduction methods that result in energy loss and component overload.
Innovation Solution
A method that utilizes a battery unit with interchangeable sub-areas connected in series or parallel, and a DC-DC converter to adjust voltage, allowing for efficient voltage reduction and energy transfer between high-voltage and low-voltage systems, enabling the use of various charging infrastructure and reducing operational losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the high-voltage electrical system is disconnected from the battery unit before charging with 400 V, then the voltage can be reduced to match the charging station, but the excess electrical energy is converted into waste heat leading to reduced efficiency
Solution Approach 1:
The DC-DC converter acts as an intermediary device between the high-voltage electrical system and the battery unit. It efficiently converts the voltage level while transferring energy, avoiding the wasteful resistive heating method. The converter enables voltage reduction from 800V to 400V while maintaining high energy efficiency and allowing the battery to be charged without disconnecting the high-voltage system.
2Adaptability or versatility
If an electrical resistor is used to reduce the electrical voltage to 400 V, then the voltage can be adjusted for charging, but the target voltage can only be set relatively imprecisely leading to voltage difference and stress on components
Solution Approach 1:
The DC-DC converter serves as a precise voltage control intermediary between the high-voltage electrical system and the battery unit. It can accurately regulate the voltage to exactly 400V or any required level, eliminating the imprecision of resistor-based voltage division. The converter maintains stable voltage output even under varying load conditions, preventing stress on electrical components.
Solution Approach 2:
The DC-DC converter dynamically adjusts electrical parameters (voltage and current) to achieve the desired output. By changing the duty cycle and switching frequency of the converter, it can precisely control the output voltage to match the battery charging requirements, unlike fixed resistor networks that cannot adapt to varying conditions.
3Use of energy by moving object
If the subunits are electrically connected in series for 800 V operation, then the high-voltage electrical system can operate at reduced current, but it is no longer possible to use charging stations that only provide 400 V
Solution Approach 1:
The system dynamically switches between series and parallel configurations of the battery subunits based on operating conditions. During normal operation, subunits are connected in series for 800V efficient operation. When a 400V charging station is available, the system switches to parallel configuration or uses the DC-DC converter to maintain series connection while stepping down voltage, ensuring both energy efficiency and charging compatibility.
Solution Approach 2:
The high-voltage electrical system is designed with multi-functionality to work with both 800V and 400V charging stations. The DC-DC converter enables the system to accept 400V input and efficiently transfer it to the 800V electrical system, or to output 400V when needed. This universal interface allows the vehicle to utilize any available charging infrastructure while maintaining optimal operating voltage.
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 allows for efficient voltage adjustment, reduced energy losses, and extended component lifespan by minimizing voltage differences and utilizing excess energy, thereby enhancing comfort, efficiency, and reducing operating costs.
Implementation Method 1
a first electrical direct current that is supplied with a first electrical voltage by a battery unit having two sub-areas that can be electrically connected in series and in parallel to one another by means of an interconnection unit is detected in a high-voltage vehicle electrical system. The electrical energy is conducted from the high-voltage vehicle electrical system to a low-voltage vehicle electrical system by means of a DC/DC converter, by which the electrical voltage is reduced
Data Source
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AI summary
The invention relates to a method (58) for operating a motor vehicle (2) comprising a high-voltage electrical system (10) and a low-voltage electrical system (22) connected by means of a DC-DC converter (20). The high-voltage electrical system (10) is connected via a switching unit (30) to a battery unit (28) which has two sub-sections (38) that can be connected electrically in series and in parallel by means of a connection unit (46). In the method (58), the switching unit (30) is opened, and the sub-sections (38) are connected electrically in parallel by means of the connection unit (46). By means of the DC-DC converter (20), electrical energy is transferred from the high-voltage electrical system (10) to the low-voltage electrical system (22), thus reducing the electrical voltage of the high-voltage electrical system (10).If the electrical voltage of the high-voltage electrical system (10) differs from the electrical voltage applied to the battery unit (28) by no more than a tolerance value, the switching unit (30) is closed. Furthermore, the invention relates to a motor vehicle (2) and a computer program product (56).