DC Charging Cable Temperature Monitoring via Signal Line Voltage
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Solution Overview
Problem
Conventional methods fail to accurately monitor the temperature of DC charging cables during fast charging sessions, leading to potential overheating and malfunction due to high currents and lack of effective temperature measurement solutions.
Innovation Solution
A DC charging cable with a signal line connected to the DC conductors allows for measuring the voltage difference between specific connection points, utilizing the thermo-electric properties of the conductors to determine the temperature, enabling precise temperature monitoring and control of charging currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional temperature monitoring methods are used, then the charging cable can be monitored during charging, but the temperature measurement is inaccurate and monitoring is incomplete
Solution Approach 1:
The charging cable uses its own DC conductors to perform temperature measurement through voltage difference measurement, rather than requiring separate external sensors. The control device measures voltage differences between connection points on the cable itself, allowing the cable to monitor its own temperature accurately and continuously throughout the charging process.
2Productivity
If high currents of 500 A or more are applied for fast charging, then charging speed is improved, but the charging cable temperature increases to 70°C or more causing overheating risks
Solution Approach 1:
The control device continuously measures the voltage difference between connection points on the charging cable during fast charging operations. Based on the measured temperature data, the system can provide feedback to adjust charging parameters or alert operators, enabling real-time temperature management while maintaining high-speed charging when conditions permit.
3Measurement precision
If the signal line is connected at both ends to DC conductors for temperature measurement, then temperature determination is accurate, but no current flows through the signal line causing measurement impossibility
Solution Approach 1:
The measurement system segments the electrical circuit by keeping the signal line electrically isolated from current-carrying paths. The signal line connects at both ends to DC conductors at different positions, allowing voltage difference measurement without current flow through the signal line itself, thus enabling accurate temperature determination while preventing measurement interference.
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 method allows for accurate temperature determination and control of the DC charging cable, preventing overheating and ensuring safe and efficient charging operations by adjusting charging currents based on measured temperatures.
Implementation Method 1
utilizing the thermo-electric properties of the conductors to determine the temperature
Implementation Method 2
the voltage difference, also referred to as voltage drop, measured between the second signal line end and the second connection point allows for determining the actual temperature
Implementation Method 3
two DC conductors configured for transmitting electrical energy between an electrical vehicle and a charging device
Implementation Method 4
Cable resistances of copper within the charging cable lead to a temperature increase of the charging cable
Data Source
AI summary
The application relates to direct current, DC, charging cable including two DC conductors configured for transmitting electrical energy between an electrical vehicle and a charging device, at least a signal line having a first signal line end and a second, opposite signal line end and a control device, the first signal line end is connected at a first connection point to one of the DC conductors, and the control device is configured for measuring a voltage difference between the second signal line end and a second connection point of the one of the DC conductors distant to the first connection point for determining a temperature of the DC charging cable.