Hybrid Vehicle EDLC Separation Switch for Voltage Stability
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Solution Overview
Problem
Hybrid-electric vehicles face significant voltage drops during engine starting, affecting auxiliary loads due to high current draws, necessitating separate electrical systems and batteries, which increase cost and weight.
Innovation Solution
An electrical system that includes a battery, an electric double-layer capacitor (EDLC), and a separation switch, where the EDLC provides power to auxiliary loads during engine starting, isolating them from the battery to maintain stable voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a separate electrical system with a separate battery is used for auxiliary loads, then the auxiliary loads can function properly during engine starting, but the cost and weight of the HEV increase
Solution Approach 1:
The patent merges the auxiliary load power supply into the main electrical system by using the existing battery and EDLC combination. The separation switch allows the battery to be electrically separated from the EDLC, enabling the battery to provide isolated power to auxiliary loads during engine starting without requiring a completely separate electrical system. This resolves the contradiction by achieving reliable auxiliary load operation while avoiding the weight penalty of an entirely separate battery system.
Solution Approach 2:
The patent segments the electrical system into distinct functional sections using the separation switch. The switch creates an electrical separation between the battery and EDLC, allowing the battery to independently power auxiliary loads during engine starting. This segmentation enables the battery to function as a dedicated auxiliary power source during critical starting operations without requiring a separate physical battery system, thereby reducing weight while maintaining reliability.
2Reliability
If a separate electrical system with a separate battery is used for auxiliary loads, then the auxiliary loads can function properly during engine starting, but the cost of the HEV increases
Solution Approach 1:
The patent combines the auxiliary load power supply function into the main electrical system architecture. By using the existing battery, EDLC, and separation switch combination, the system achieves proper auxiliary load functionality during engine starting without requiring a completely separate electrical system. This merging approach reduces component count and system complexity, thereby lowering manufacturing costs while maintaining reliability.
3Power
If the battery provides power to auxiliary loads during engine starting, then the voltage across the battery drops significantly, but using a separate battery system adds weight and cost
Solution Approach 1:
The separation switch segments the electrical circuit to isolate the battery from the EDLC during engine starting operations. This segmentation allows the battery to provide high current draws to auxiliary loads without causing voltage drops to affect the EDLC or other sensitive electrical components. The battery operates in an electrically isolated section, maintaining voltage stability for the overall system while delivering the required power.
Solution Approach 2:
The separation switch acts as an intermediary device that controls the electrical connection between the battery and EDLC. During engine starting, the switch opens to prevent the battery's high current draw from causing voltage drops across the EDLC and other sensitive loads. This intermediary mechanism allows the battery to deliver high power while protecting the voltage stability of the broader electrical system.
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 eliminates the need for separate batteries and systems, maintaining stable voltage to auxiliary loads during engine starting, reducing weight and cost while ensuring proper functionality.
Implementation Method 1
An electric double-layer capacitor ('EDLC') electrically connectable to the battery and the auxiliary load
Data Source
AI summary
An electrical system includes a battery for providing electrical power to a starter mechanism and an auxiliary load of a hybrid-electric vehicle. An electric double-layer capacitor (“EDLC”) is electrically connectable to the battery and the auxiliary load. A separation switch is electrically connected between the battery and the EDLC for electrically separating the battery from the EDLC and the auxiliary load. The separation switch is opened in response to the voltage across the battery being less than the voltage across the EDLC.