Modular Fuel Cell Research Articles

The FCH2RAIL Project: A Demonstration of a Modular Fuel Cell Hybrid Power Pack

In this paper, the Horizon 2020 project FCH2RAIL is outlined. The project aims to develop a bi-modal propulsion system, which combines an overhead catenary powertrain and a hydrogen fuel cell battery electric hybrid system to enable operation on tracks with mixed electrification. A key element is the fuel cell hybrid power pack and its modularity. Therefore, a methodology was developed to derive generic and well-suited fuel cell and battery block sizes. A work flow is set up, which combines a vehicle simulation and a fuel cell hybrid propulsion system model. Using statistical analysis, required battery and fuel cell block sizes are derived. With the developed methodology, 17 kWh were determined for the battery block and 47 kW for the fuel cell block. These dimensions are well-covered by market-available components, which demonstrates the applicability of the proposed methodology.

Experimental Results for an Off-Road Vehicle Powered by a Modular Fuel Cell Systems Using an Innovative Startup Sequence

This article deals with implementing a rule-based control method and startup sequence of a hybrid electric vehicle powered by a modular fuel cell system as its primary energy source and a lithium-ion battery system as its secondary energy source. The modular fuel cell system is composed of two separate fuel cell systems, electrically coupled to a one-power converter, using a programmable device. Depending on the vehicle’s operating mode, either both systems are used or just one of them. The vehicle’s fuel efficiency is improved by operating at constant power in the peak efficiency range of each fuel cell system. The experimental results show that the proposed system can significantly improve the fuel economy of a fuel cell vehicle and extend the driving range, while avoiding start/stop cycles. Additionally, this solution can increase the fuel cells’ lifecycle.

Modular Fuel Cell System Simulation Environment with Focus on Membrane Water Management

Modular Fuel Cell System Simulation Environment with Focus on Membrane Water Management

Comparison of Decentralized ADMM Optimization Algorithms for Power Allocation in Modular Fuel Cell Vehicles

The advanced modular powertrains are envisioned as primary part of future hybrid fuel cell vehicles (FCVs). The existing papers in the literature solely cope with the hardware side of modularity, while the software side is also vital to capitalize on the total capacity of these powertrains. Driven by this motivation, this article puts forward a comparative study of two novel decentralized convex optimization frameworks based on alternating direction method of multipliers (ADMM) to solve a multi-objective power allocation strategy (PAS) problem in a modular FCV (MFCV). The MFCV in this article is composed of two fuel cell (FC) stacks and a battery pack. Despite the existing centralized strategies for such a modular system, this manuscript proposes two decentralized PASs (Dec-PASs) based on Consensus ADMM (C-ADMM) and Proximal Jacobian ADMM (PJ-ADMM) to bridge the gap regarding the appreciation of modularity in software terms. Herein, after formulating the central PAS optimization problem, the principle of utilizing such decentralized algorithms is presented in detail. Subsequently, the performance of the proposed Dec-PASs is examined through several numerical simulations as well as experiments on a developed small-scale test bench. The obtained results illustrate that decomposition into decentralized forms enables solving the complex PAS optimization problem faster and provides modularity and flexibility. Furthermore, the proposed Dec-PASs can cope with fault and malfunction and thus augment the durability and robustness of modular powertrain systems.

Power Allocation Strategy Based on Decentralized Convex Optimization in Modular Fuel Cell Systems for Vehicular Applications

Recently, modular powertrains have come under attentions in fuel cell vehicles to increase the reliability and efficiency of the system. However, modularity consists of hardware and software, and the existing powertrains only deal with the hardware side. To benefit from the full potential of modularity, the software side, which is related to the design of a suitable decentralized power allocation strategy (PAS), also needs to be taken into consideration. In the present study, a novel decentralized convex optimization (DCO) framework based on auxiliary problem principle (APP) is suggested to solve a multi-objective PAS problem in a modular fuel cell vehicle (MFCV). The suggested decentralized APP (D-APP) is leveraged for accelerating the computational time of solving the complex problem. Moreover, it enhances the durability and the robustness of the modular powertrain system as it can deal with the malfunction of the power sources. Herein, the operational principle of the suggested D-APP for the PAS problem is elaborated. Moreover, a small-scale test bench based on a light-duty electric vehicle is developed and several simulations and experimental validations are performed to verify the advantages of the proposed strategy compared to the existing centralized ones.

Analytical Comparision between Single and Modular Fuel Cell Stack: Uniform Modular Cell Approch

A single fuel cell (FC) produces a very small voltage of about 0.6 -0.8 V under normal operating condition, and hence several individual cells are connected in series as a stack to get higher voltages suitable for practical loads. The stacks are then connected in series to get required values of DC voltage. The FC performance varies with the operating parameters such as temperature, humidity, fuel flow rate, ageing and fuel non uniform concentration. The FC stack underperforms when there is presence of bad cell in it. The Presence bad cell in a stack limits the current handling capacity of other healthy cells when it’s connected as a conventional single stack. This can be overcome by connecting the fuel cells in uniform modular cell configuration. In this paper a Uniform Modular Cell Configuration (UMCC) is proposed to gain the maximum power from the stack and the conventional Single or Uni Stack Configuration (USC) is compared with the proposed structure. A detail mathematical analysis of comparing both methods is described. Further the superiority of the proposed method is proven by carrirying out the simulations under steady state operating condition of a FC stack feeding to a constant current load.

Design Methodology of a Proton Exchange Membrane Modular Fuel Cell of 100 W Power Output

The design of the fuel cell plays a major role in determining their cost. It is not only the cost of materials that increases the cost of the fuel cell, but also the manufacturing techniques and the need for skilled technicians for assembling and testing the fuel cell. The work presented in this paper is part of a research work aims to design and manufacture a proton exchange membrane (PEM) modular fuel cell of 100 W output at low cost using conventional materials and production techniques, then testing the fuel cell to validate its performance. This paper will be dealing only with the design of a modular fuel cell that can be mass produced and used to set up a larger fuel cell stack for stationary applications (6 kW) which is capable of powering a medium sized household. The design for 100 W fuel cell module will include the calculations for the main dimensions of the fuel cell components, mass flow rate of reactants, water production, heat output, heat transfer and the cooling system. This work is intended to facilitate material and process selection prior to manufacturing alternatives prior to capital investment for wide-scale production. The authors believe that the paper would lead to a stimulating discussion.

A Modular Fuel Cell, Modular DC–DC Converter Concept for High Performance and Enhanced Reliability

Fuel cell stacks produce a DC output with a 2:1 variation in output voltage from no-load to full-load. The output voltage of each fuel cell is about 0.4 V at full-load, and several of them are connected in series to construct a stack. An example 100 V fuel cell stack consists of 250 cells in series and to produce 300 V at full-load requires 750 cells stacked in series. Since fuel cells actively convert the supplied fuel to electricity, each cell requires proper distribution of fuel, humidification, coupled with water/thermal management needs. With this added complexity, stacking more cells in series decreases the reliability of the system. For example, in the presence of bad or malperforming cell/cells in a stack, uneven heating coupled with variations in cell voltages may occur. Continuous operation under these conditions may not be possible or the overall stack output power is severely limited. In this paper, a modular fuel cell powered by a modular DC-DC converter is proposed. The proposed concept electrically divides the fuel cell stack into various sections, each powered by a DC-DC converter. The proposed modular fuel cell powered by modular DC-DC converter eliminates many of these disadvantages, resulting in a fault tolerant system. A design example is presented for a 150-W, three-section fuel cell stack and DC-DC converter topology. Experimental results obtained on a 150-W, three-section proton exchange membrane (PEM) fuel cell stack powered by a modular DC-DC converter are discussed.

A Modular Fuel Cell, Modular DC-DC Converter Concept for High Performance and Enhanced Reliability

Bad or mal performing cells in a fuel cell stack cause uneven heat distribution and reduced terminal voltage. As a consequence the overall output power of the system is reduced. Moreover continuous operation under these conditions may not be possible due to excessive heat generation in underperforming cells. In this paper a modular fuel cell powered by a modular DC-DC converter is proposed. This approach electrically divides the fuel cell stack into various sections, each powered by a DC-DC converter, allowing loading each section in the stack according to its state. That is better performing sections handle more load than underperforming sections while the output voltage of the system is kept regulated. In addition the proposed approach can bypass mal-functioning sections while the rest of the stack can continue operation, thus improving the reliability of the system. Experimental results on a 150W prototype confirm the benefits of the proposed approach.

Development of a Modular Fuel Cell Generator: Description of 4kW Modular Unit

Diesel generators are already a major source of air pollution in the United States and they are growing in numbers and in total installed capacity every year. Now is an ideal time for regulators and industry to pursue strategies to advance the fuel cell which is a clean and economic alternative to the diesel generator. More specifically, PEM fuel cells are commonly considered the most promising fuel cell technology in that they combine high power density and specific power with fast start up, fast response, and environmental friendliness. Fuel cells need hydrogen gas as their fuel but that can be generated by reformation or electrolysis and stored in compressed gas cylinders at reasonable densities. At MER, we have designed, built and tested a compact 4kW fuel cell modular unit as a part of a 72 kW fuel cell generator. The viability, flexibility, redundancy, reliability and cost-effectiveness of the modular concept are demonstrated in this paper.