Capacitor Charging Circuit with PTC Thermistor Current Regulation
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Solution Overview
Problem
Existing energy storage solutions for motor vehicles, such as lead acid batteries, have limitations in terms of cyclization, weight, and scalability, and lack effective current regulation during charging, which can lead to overheating and circuit damage.
Innovation Solution
A circuit comprising a capacitor, a temperature-dependent resistor, and a diode for charging and discharging, where the temperature-dependent resistor, such as a PTC thermistor, regulates current flow to prevent overheating, and additional resistors provide cost and design benefits, allowing for the use of double layer capacitors like UltraCAPs without a circuit board.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a temperature-dependent resistor (PTC thermistor) is used to limit current flow during charging, then circuit protection from overheating and excessive current is improved, but device complexity and cost increase
Solution Approach 1:
The PTC thermistor provides self-regulating current limitation through its inherent temperature-dependent resistance properties. When excessive current flows causing temperature rise, the thermistor's resistance automatically increases to limit current without requiring external control circuits or additional active components,实现ing circuit protection through self-service
Solution Approach 2:
The invention utilizes the temperature-dependent resistance parameter of the PTC thermistor to dynamically adjust current limiting based on thermal conditions. The resistance value changes with temperature, providing adaptive circuit protection that responds to operating conditions without adding complex control logic
2Quantity of substance
If double layer capacitors (UltraCAPs) are used for energy storage, then energy density and cyclization are improved, but current regulation capability deteriorates without additional components
Solution Approach 1:
The PTC thermistor acts as an intermediary component between the power source and the double layer capacitor during charging. It mediates the current flow by providing temperature-dependent resistance that automatically regulates current, protecting the capacitor from excessive current while maintaining the capacitor's high energy density benefits
3Reliability
If conventional resistors are replaced with temperature-dependent resistors for current limiting, then circuit protection is improved, but manufacturing cost increases
Solution Approach 1:
The PTC thermistor replaces complex active protection circuits with a passive self-regulating component. The thermistor's inherent temperature-dependent properties provide automatic current limiting and circuit protection without requiring additional control electronics, microcontrollers, or complex manufacturing processes, thereby reducing overall system complexity and manufacturing cost despite the higher unit cost of the thermistor itself
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 high cyclization, reduced weight and size, and prolonged operational life for motor vehicle energy storage, eliminating the need for frequent replacements and providing effective current regulation to prevent overheating.
Implementation Method 1
the temperature-dependent resistor is a PTC thermistor (PTC=positive temperature coefficient). One property of such a PTC thermistor is that the resistance it provides increases at higher temperatures.
Implementation Method 2
A circuit for storing electrical energy, in particular for installation within a motor vehicle, having at least one capacitor
Data Source
AI summary
A circuit for storing electrical energy, in particular for installation within a motor vehicle, comprises at least one capacitor and a temperature-dependent resistor by means of which the at least one capacitor can be charged. The circuit may be included in a motor vehicle. Alternatively, a motor vehicle may be retrofit to include the circuit.