Charging Cable Bad Contact Detection via Fluid Temperature
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Solution Overview
Problem
Existing electrical charging stations face challenges in reliably detecting bad contacts between charging cables and electric vehicles, which can lead to overheating due to increased resistance caused by dirt, damage, or corrosion, especially during high-current fast charging.
Innovation Solution
A method involving temperature measurements of the cooling fluid and connector base in the charging cable, where the estimated contact temperature is calculated from the difference between the cooling fluid and connector base temperatures, allowing for the detection of bad contacts by comparing it to a threshold temperature, and subsequently controlling the charging current to prevent overheating.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If temperature sensors are installed directly at the electrical contact element to measure contact temperature, then measurement precision is improved, but device complexity and ease of manufacture worsen due to the difficulty of wiring temperature sensors along contact elements
Solution Approach 1:
The patent introduces the cooling fluid as an intermediary medium to indirectly measure the contact temperature. Instead of placing sensors directly at the contact element, the cooling fluid circulates through channels in the connector base, absorbing heat from the contact element. The temperature of the cooling fluid serves as a proxy for the contact temperature, enabling measurement without direct sensor contact with the electrical contact element.
Solution Approach 2:
The patent replaces the mechanical approach of directly wiring temperature sensors to contact elements with a thermal field-based approach. By using the cooling fluid's temperature to represent the contact temperature, the system substitutes direct mechanical sensor contact with indirect thermal measurement, simplifying the mechanical complexity of sensor installation while maintaining measurement capability.
2Device complexity
If cooling fluid temperature is used as a direct measure of contact temperature, then device complexity is reduced, but measurement precision deteriorates because cooling fluid temperature does not directly reflect contact element temperature
Solution Approach 1:
The patent implements a feedback mechanism by continuously monitoring the cooling fluid temperature and using this information to infer the contact temperature. The system establishes a relationship between the cooling fluid temperature and the contact element temperature, allowing the controller to adjust and interpret the temperature data appropriately to detect bad contacts accurately.
Solution Approach 2:
The patent changes the measurement parameter from direct contact element temperature to cooling fluid temperature. By monitoring the temperature of the cooling fluid that circulates through the connector base, the system obtains an indirect but reliable indicator of contact temperature, simplifying the measurement system while maintaining detection accuracy through proper parameter selection and interpretation.
3Productivity
If high currents are used for fast charging, then productivity is improved, but the risk of bad contact and overheating increases due to higher thermal load on contact elements
Solution Approach 1:
The patent ensures continuous monitoring of the cooling fluid temperature throughout the charging process. By continuously measuring the temperature and comparing it against threshold values, the system maintains ongoing detection of potential bad contacts, allowing for real-time intervention before overheating occurs, thus enabling safe high-current charging operations.
Solution Approach 2:
The patent converts the harmful effect of heat generation during high-current charging into a useful detection mechanism. The heat that would normally indicate a problem is instead used as a signal - by monitoring the cooling fluid temperature, the system transforms thermal energy from a harmful byproduct into a beneficial indicator for detecting bad contacts and preventing overheating.
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 effectively detects bad contacts, preventing overheating and ensuring safe charging operations by reliably distinguishing between normal and abnormal temperature conditions, thereby reducing the risk of damage to components.
Implementation Method 1
The cooling cable may be cooled with cooling fluid that may be pumped by the charging station through the charging cable and the plug
Implementation Method 2
measuring a cooling fluid temperature of a cooling fluid flowing through the charging cable; measuring a connector base temperature of a connector base of the charging cable
Implementation Method 3
A bad contact may result in a strong heating of the plug and other components
Data Source
AI summary
A method for detecting a bad contact of a charging cable comprises: measuring a cooling fluid temperature of a cooling fluid flowing through the charging cable; measuring a connector base temperature of a connector base of the charging cable, which connector base carries an electrical contact element of the charging cable; estimating a contact temperature of the electrical contact element by determining the contact temperature from a difference of the connector base temperature and the cooling fluid temperature; and deciding presence of a bad contact, when the estimated contact temperature is higher than a threshold temperature.