Supercapacitor Liftgate Power Architecture for Reliable Vehicle Starting
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Solution Overview
Problem
Delivery trucks with lift gates often face battery run-down issues due to high energy demands, especially in extreme temperatures or when the engine is not regularly started, leading to potential immobilization of the vehicle, as the same battery powers both the truck's starting and the lift gate, resulting in costly service calls.
Innovation Solution
A hybrid power system incorporating lithium-ion batteries and super-capacitor banks, where the super-capacitors assist both vehicle starting and lift gate energy needs, with a diode ensuring parallel communication between capacitor banks and batteries to maintain power supply, and a DC/DC boost converter acting as a secondary alternator to support peak currents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the same battery is used for both vehicle starting and lift gate operation, then the device complexity is reduced, but the reliability deteriorates due to battery run-down and potential immobilization
Solution Approach 1:
The power system is segmented into two independent battery systems: a primary battery for vehicle starting and a secondary battery for lift gate operation. This segmentation allows each battery to be optimized for its specific function and prevents cross-contamination of power demands, resolving the reliability issue while maintaining manageable complexity through modular architecture
Solution Approach 2:
A DC-DC converter is introduced as an intermediary device between the two battery systems to manage power flow and voltage conversion. This mediator enables independent operation of each battery system while providing controlled power transfer when needed, enhancing reliability without requiring direct coupling of the battery systems
2Reliability
If the battery capacity is increased to support both starting and lift gate operations, then the reliability improves, but the weight increases
Solution Approach 1:
Instead of using one large battery, the system divides the power storage function into two separate batteries of appropriate sizes for their respective functions. The primary battery is sized for starting operations while the secondary battery is sized for lift gate operations, reducing total weight compared to a single oversized battery while maintaining reliability
Solution Approach 2:
The secondary battery system is designed to serve multiple functions: powering the lift gate operation and providing auxiliary power during starting operations if needed. This multi-functionality allows the system to maintain reliability without requiring excessive battery capacity dedicated solely to starting
3Reliability
If a separate battery is used for the lift gate, then the reliability improves, but the device complexity increases
Solution Approach 1:
The secondary battery system is designed with multi-functionality to justify the added complexity: it powers the lift gate operation independently and can also assist during vehicle starting operations. This dual capability provides sufficient return on investment for the increased system complexity
Solution Approach 2:
A DC-DC converter serves as an intermediary that manages the complexity of having two battery systems by automating power flow control and voltage regulation. This intelligent mediator simplifies the control architecture and reduces the need for complex manual intervention or switching mechanisms
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
The system ensures reliable engine starting and continuous operation of the lift gate, even when batteries are weak, by providing independent power through super-capacitors and extending battery life by managing peak currents and voltage balancing.
Implementation Method 1
A hybrid power system incorporating lithium-ion batteries and super-capacitor banks
Implementation Method 2
The alternator includes a rotor shaft that is turned by a pulley and drive belt system. When the engine is started, the pulley turns the rotor shaft, causing the rotor to act as a spinning electro-magnet. As the pulley is rotated, alternating current (AC) passes through a magnetic field and an electrical current is generated.
Implementation Method 3
with a diode ensuring parallel communication between capacitor banks and batteries to maintain power supply
Data Source
AI summary
An electrical power system for a delivery vehicle. The power system is used in connection with a vehicle having an engine, and a liftgate powered by an electric motor. The power system includes a first battery, a second battery, and an alternator. The electrical power system also includes a super capacitor. The super capacitor has a first capacitor bank and a second capacitor bank, wherein each of the first and second capacitor banks comprises ultra-capacitor cells placed in series. The first and second capacitor banks reside in parallel. In addition, the first and second batteries reside in parallel with the second capacitor bank. Together, the batteries and the second capacitor bank supply power to the liftgate motor. Finally, the first capacitor bank is in electrical communication with the alternator and supplies power, with the alternator, to a relay start for the delivery vehicle to start the engine.