Fuel Cell Stack and Battery Sizing for Vehicle Power Optimization
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Solution Overview
Problem
The design of fuel cell vehicles is hindered by a lack of development history and maturity, leading to increased development costs and extended development periods compared to hybrid vehicles, due to the need for adjusting various parts and modules, and there is a need for a method to reduce these costs and periods while ensuring maximum output and cruise condition performance.
Innovation Solution
A method is proposed for designing a machine with a fuel cell stack, drive motor, and secondary battery, where the maximum output of the drive motor and fuel cell stack are determined, and the number of fuel cell stacks is optimized to satisfy cruise condition outputs, with the secondary battery's maximum output calculated to supplement the fuel cell stack's output, maintaining state of charge and allowing for efficient maximum output exertion.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If fuel cell stack design is newly developed for each machine, then the machine can be optimized for specific requirements, but the development cost and development period increase enormously
Solution Approach 1:
The patent segments the fuel cell vehicle design into standardized modules (fuel cell stack, secondary battery, drive motor) that can be independently designed and then combined. This allows the fuel cell stack to be standardized while still enabling machine-specific optimization through modular reconfiguration, thereby reducing development time without sacrificing adaptability.
Solution Approach 2:
The patent applies parameter changes by establishing standardized output parameters for fuel cell stacks (e.g., 65kW, 130kW, 195kW) and selecting appropriate combinations to meet different machine requirements. This standardization approach reduces development complexity while maintaining the ability to optimize for specific machine needs through parameter selection rather than complete redesign.
2Power
If the number of fuel cell stacks is increased to satisfy maximum output, then the maximum output requirement is met, but the output during cruise condition may become excessive
Solution Approach 1:
The patent implements a dynamic power distribution system where the controller dynamically adjusts the contribution of fuel cell stacks and secondary battery based on real-time power demands. During cruise conditions, the system dynamically reduces fuel cell output and supplements with secondary battery discharge, preventing excessive energy production. During maximum output demands, the system dynamically combines both power sources to meet peak requirements.
Solution Approach 2:
The patent intentionally designs the fuel cell stack capacity to be sufficient for maximum output requirements, even though this creates partial excess capacity during cruise conditions. The excess capacity is then managed through the secondary battery system, which absorbs or supplements power as needed, allowing the fuel cell stacks to be optimally sized for peak performance without wasting potential during normal operation.
3Power
If the secondary battery capacity is increased to support maximum output, then the maximum output exertion is improved, but the device complexity and cost increase
Solution Approach 1:
The patent uses a standardized secondary battery design that can be copied and applied across different fuel cell vehicle models. By establishing a template battery system with standardized capacity and configuration, the patent reduces device complexity while maintaining the ability to support maximum output requirements. The same battery design can be reused across different vehicle types, reducing overall system complexity.
4Use of energy by moving object
If fuel cell stack output is optimized for cruise condition, then cruise traveling is ensured, but the maximum output may be insufficient
Solution Approach 1:
The patent designs the fuel cell stack with multi-functionality to serve both cruise condition power supply and maximum output contribution. The standardized fuel cell stacks are designed with output capacities that can fulfill both roles: providing base power during cruise and contributing to peak power when combined with secondary battery discharge. This universal design eliminates the need for separate optimization for different operating conditions.
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 reduces development costs and periods by reusing fuel cell stack designs and optimizing secondary battery capacity, ensuring efficient cruise condition performance and maintaining state of charge, thus avoiding output shortages during maximum output exertion.
Implementation Method 1
a fuel cell stack configured to generate an electric current for driving the drive motor
Implementation Method 2
a secondary battery configured to discharge an electric current for driving the drive motor
Data Source
AI summary
A method of designing a machine on which a drive motor, a fuel cell stack, and a secondary battery are mounted includes: determining a maximum output of the drive motor to be a first output value and an output of the drive motor when a vehicle travels under a cruise condition to be a second output value; determining the number of fuel cell stacks to be mounted to be n; and determining a maximum output of the secondary battery to be a value obtained by subtracting a value obtained by multiplying a maximum output of the fuel cell stack by the n, from the first output value. A value obtained by multiplying the third output value by the n is equal to or larger than the second output value, and a value obtained by multiplying the third output value by (n−1) is less than the second output value.