Fuel Cell Battery Power Management for Sustained Uphill Loads
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Solution Overview
Problem
Fuel cell power alone may not be sufficient to meet sustained high power demand in vehicles, especially during uphill grades with heavy payloads, and battery power assistance is limited by state of charge, leading to degraded vehicle performance over time.
Innovation Solution
A fuel cell and battery power management system that proactively adjusts power levels and state of charge based on predicted grade information, using connectivity-based data to optimize battery charging and discharging strategies, ensuring consistent powertrain torque and energy capture.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If battery power assist is used to meet sustained high power demand during uphill grades, then vehicle power capability is improved, but battery state of charge depletes over time causing performance degradation
Solution Approach 1:
The system performs preliminary charging of the battery during downhill grades and level road sections before the uphill grade is reached. By proactively building up battery state of charge in advance using regenerative braking during descents and normal operation during level sections, the system ensures sufficient battery power is available to assist during the upcoming sustained uphill grade, thereby extending the duration of battery assistance without compromising peak power capability.
2Power
If battery state of charge is depleted to provide power assist during uphill grades, then power capability is improved, but powertrain braking performance degrades when SOC rises to maximum
Solution Approach 1:
The system implements periodic alternation between battery charging and discharging phases. During downhill grades and level sections, the battery is charged (including regenerative braking). During uphill grades requiring high power, the battery discharges to assist. This periodic cycling prevents the battery from remaining in extreme SOC states, maintaining it within an optimal range that preserves both power assist capability and powertrain braking performance throughout the trip.
3Device complexity
If fuel cell power alone is used to navigate uphill grades, then system simplicity is maintained, but power sufficiency is compromised under heavy payload conditions
Solution Approach 1:
The system dynamically adjusts the power contribution from the fuel cell and battery based on real-time conditions including upcoming grade, current battery state of charge, and power demand. The control system continuously optimizes the power split between fuel cell and battery, increasing battery assist during sustained high-power demands like uphill grades with heavy payload, while returning to fuel cell-dominated operation during downhill or level sections. This dynamic power management ensures power sufficiency without requiring permanent oversizing of the fuel cell 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
Enhances vehicle performance by maintaining consistent powertrain torque and energy capture, even under varying load conditions, by strategically managing fuel cell and battery power to meet power demands and extend battery assistance.
Implementation Method 1
A fuel cell stack is in electrical communication with the traction battery and the electric traction motor
Implementation Method 2
The traction battery includes a battery state of charge
Data Source
AI summary
A fuel cell and battery power management system for a fuel cell-powered vehicle includes an electric traction motor, a traction battery in electrical communication with the electric traction motor, a fuel cell stack in electrical communication with the traction battery and the electric traction motor, and a vehicle control system. The vehicle control system is configured to operate the vehicle with at a first discharge power level and a first charging power level if fuel cell power is sufficient alone to navigate the uphill grade and to build up battery state of charge by charging the traction battery at a second charging power level when the vehicle is approaching an uphill grade if fuel cell power is not sufficient alone to navigate the uphill grade. The vehicle control system is further configured to initiate proactive depletion of the battery SOC to enable powertrain braking and to provide regenerative power.