Voltage Conversion Device for EV Battery Thermal Management
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Solution Overview
Problem
Motored vehicles face challenges in rapidly increasing the temperature of power storage devices when charging from an external power supply, especially at low temperatures, which affects the charging/discharging characteristics and efficiency.
Innovation Solution
A voltage conversion device is configured to allow power storage devices in a motored vehicle to communicate electric power between each other during charging, enabling rapid temperature increase by controlling the converters to manage the charging process effectively.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by stationary object
If the power storage device is charged from an external power supply at low temperature, then the charging cost is reduced (midnight electricity is inexpensive), but the charging characteristic decreases and the device cannot be charged to full capacity
Solution Approach 1:
The system performs preliminary heating of the power storage device before charging by having the first power storage device discharge to the second power storage device through the voltage conversion device. This preliminary action raises the temperature of both devices, ensuring they are at an optimal temperature for efficient charging from the external power supply, thus resolving the contradiction between low-cost midnight charging and maintaining good charging characteristics.
2Reliability
If the power storage device temperature is increased rapidly to improve charging characteristic, then the charging efficiency improves, but the charging time may be extended due to temperature management requirements
Solution Approach 1:
The system uses the power storage devices themselves to generate the heat needed for temperature management through internal resistance heating during discharge and charge cycles. The first power storage device discharges to the second power storage device, and both devices generate heat through their internal resistance, eliminating the need for external heating systems and reducing overall charging time while maintaining optimal charging characteristics.
3Device complexity
If a single power storage device is used, then the system structure is simple, but the temperature management capability and charging efficiency at low temperature are insufficient
Solution Approach 1:
The system divides the power storage function into multiple independent power storage devices (first and second power storage devices), each capable of independent charge and discharge operations. This segmentation allows one device to serve as a heat source while the other is charged, providing effective temperature management capability that would be impossible with a single device, while keeping each individual device relatively simple in structure.
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 enables power storage devices to be rapidly charged and achieve a sufficient charging characteristic in a short period, even at low temperatures, ensuring efficient energy storage and vehicle operation.
Implementation Method 1
a voltage conversion device which converts in voltage an electric power that an electric power receiving unit receives and outputs the converted electric power to a plurality of power storage devices
Implementation Method 2
the plurality of power storage devices communicate electric power therebetween... after charging is started, the plurality of power storage devices are rapidly increased in temperature
Data Source
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AI summary
In charging first and second power storage devices (6-1, 6-2) from a charging station, an inverter ECU (32) controls first and second inverters (30-1, 30-2) to convert AC power received at first and second neutral points (N1, N2) into DC power and output the DC power to a power supply system (1). A converter ECU (2) converts in voltage the electric power received from the first and second inverters (30-1, 30-2) to be charged and outputs the converted electric power to the first and second power storage devices (6-1, 6-2), and for low temperature, controls first and second converters (8-1, 8-2) to allow the first and second power storage devices (6-1, 6-2) to communicate electric power therebetween.