Fuel Cell Vehicle Downtime Planning for Boil-Off Energy Storage
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Solution Overview
Problem
Vehicles with fuel cell systems face energy loss and reliability issues when parked, particularly at freezing temperatures, due to hydrogen boil-off and frozen fuel cell components, which require energy to thaw and convert hydrogen into electrical energy efficiently.
Innovation Solution
A method for planning vehicle utilization that preconditions vehicle components, such as the traction battery and fuel cell system, by selecting downtime points and durations to maintain a defined charging status, allowing for complete storage or consumption of electrical energy from the boil-off management system, ensuring sufficient energy for heating and defrosting, and coordinating with external parameters like weather and tank pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the vehicle is parked for a longer period, then the tank slowly warms up causing liquid hydrogen to evaporate and pressure to rise, but hydrogen must be removed from the tank to reduce pressure, leading to energy loss
Solution Approach 1:
The system performs preliminary actions by converting boil-off hydrogen to electrical energy in advance during vehicle operation, storing it in the traction battery before parking occurs. This ensures energy is available without needing to remove hydrogen during parking, eliminating the contradiction between extended parking duration and hydrogen energy loss.
2Reliability
If heat is supplied to the fuel cell system to thaw frozen water at low ambient temperatures, then the fuel cell system can work properly, but energy is required to generate the heat
Solution Approach 1:
The fuel cell system performs self-service by using its own generated electrical energy to heat and thaw frozen components. The control unit directs electrical energy from the fuel cell system to the heating element, eliminating the need for external energy sources and resolving the contradiction between maintaining reliability and reducing energy consumption.
3Loss of energy
If the charging status of the traction battery is optimized for storing boil-off energy, then complete electrical energy from the boil-off management system can be stored, but the battery must have sufficient capacity to also provide heating energy for the fuel cell system
Solution Approach 1:
The control unit dynamically adjusts the charging status area of the traction battery based on operational requirements. It coordinates between storing boil-off energy and reserving capacity for heating, optimizing the charging status range to satisfy both energy storage and heating needs without requiring excessive battery capacity, thus resolving the contradiction between energy loss reduction and battery quantity requirements.
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 enables energy-efficient and reliable vehicle operation by preventing hydrogen release, ensuring sufficient battery capacity for heating and defrosting, and allowing for flexible vehicle downtime planning, thus minimizing energy waste and ensuring operational readiness.
Implementation Method 1
vehicles with a fuel cell system are also known, with the aid of which electrical drive energy is obtained by reacting a fuel gas, usually hydrogen, with an oxidizing agent, usually oxygen
Implementation Method 2
The thermal insulation prevents the fuel tank from heating up too quickly, which causes liquid fuel gas to evaporate and the internal tank pressure to rise too quickly
Implementation Method 3
a heating element 53, which warms a fuel cell system 5 to an operating temperature
Data Source
AI summary
The invention pertains to a method for planning a vehicle utilization of a vehicle (1), wherein at least one vehicle component is preconditioned during the vehicle utilization. The invention is characterized in that a point in time, a duration and/or a number of vehicle downtimes to be carried out during vehicle utilization are selected such that at least one traction battery (2) of the vehicle (1) has a charging status within a defined state of charging status area (3) at the beginning of a vehicle downtime, so that an amount of electrical energy provided by a boil-off management system during the vehicle downtime is stored completely in the traction battery (2) or is stored partially in the traction battery (2) and consumed completely by a third-party consumer (4) during the vehicle downtime, and an amount of electrical energy available in the traction battery (2) at the beginning of the vehicle downtime is sufficient to heat a fuel cell system (5) of the vehicle (1) to an operating temperature at the end of the vehicle downtime.