EV Charging Cord Reel Thermal Sensing for Variable Current Control
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Solution Overview
Problem
Retractable cord reels used in electric vehicle charging stations generate excessive heat due to current flow, which can damage the cord and pose safety risks, especially when the cord is coiled, leading to reduced useful life and potential hazards.
Innovation Solution
Incorporating temperature sensors and control circuitry that regulate current flow based on thermal buildup and unreeled cord length, along with venting mechanisms like a 'chimney effect' to dissipate heat, allowing for higher currents when the cord is unreeled and ensuring safe dissipation of heat generated.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the cord is coiled on a reel for storage, then storage convenience and protection from damage are improved, but heat dissipation deteriorates leading to excessive heat buildup
Solution Approach 1:
The patent applies dynamics by making the current limiting adjustable based on cord configuration. The system dynamically adapts the current limit according to whether the cord is coiled or uncoiled, using sensors to detect cord state and control circuitry to adjust current delivery accordingly. This resolves the contradiction by allowing high current when uncoiled (good heat dissipation) while maintaining storage convenience when coiled.
Solution Approach 2:
The patent changes the electrical parameter (current limit) based on the thermal conditions created by cord coiling. By detecting cord temperature or coiling state and adjusting the current parameter dynamically, the system optimizes both storage convenience and heat dissipation performance.
2Temperature
If current flow is limited to prevent overheating, then temperature control is improved, but charging speed deteriorates
Solution Approach 1:
The system dynamically adjusts current delivery based on real-time detection of cord temperature and coiling state. When the cord is uncoiled and heat dissipation is effective, higher currents are permitted for faster charging. When coiled and heat buildup occurs, current is reduced to prevent damage. This dynamic adaptation resolves the contradiction between temperature control and charging speed.
Solution Approach 2:
The patent implements feedback control by using temperature sensors to monitor cord conditions and feeding this information back to the control circuitry, which adjusts current delivery accordingly. This closed-loop system optimizes charging speed while preventing overheating, resolving the contradiction between productivity and temperature control.
3Temperature
If the cord is partially unreeled for charging, then heat dissipation is improved, but cord storage protection deteriorates
Solution Approach 1:
The system dynamically determines the optimal cord state (coiled or uncoiled) based on charging requirements and environmental conditions. The control circuitry can command the reel to uncoil or coil the cord appropriately, balancing heat dissipation needs with protection requirements. This dynamic control resolves the contradiction between heat dissipation and cord protection.
4Temperature
If temperature sensors and control circuitry are added, then thermal management is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex mechanical thermal management systems with electronic sensing and control. Instead of mechanical vents or movable components, the system uses temperature sensors and electronic control circuitry to manage heat, reducing mechanical complexity while improving thermal management capability.
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 prevents overheating, allows for maximum charging current delivery, detects cord damage or removal, and ensures safe operation by dynamically adjusting current flow and enhancing heat dissipation, thereby extending cord life and ensuring user safety.
Implementation Method 1
The reel has one or more temperature sensors for determining the thermal buildup in the cord
Implementation Method 2
Heat generated by the flow of current will not escape as readily from a cord carrying electrical current when the cord is partially or completely coiled or retracted
Implementation Method 3
In some embodiments, the charging station includes a venting mechanism to vent heat generated in the cord
Data Source
AI summary
A battery charging assembly includes a load management system, a charging cord with a battery connector, and circuitry for detecting thermal buildup. The load management system monitors the heat buildup in a coiled portion of the charging cord and issues a corresponding signal to control the current flowing through the cord.