**2. Fuel cell vehicles**

Fuel cell technology is gaining popularity in the automotive industry due to its ease of use, quiet operation, high efficiency, and modular structure. According to Mustafa et al., recent investigations have showed that the usage of fuel cells in vehicles has expanded rapidly, causing a revolution, and will be an alternative to conventional vehicles in the future (2021). Configuration, system components, control/management, technical obstacles, marketing, and future aspects are all categories for fuel cell cars. Based on chemical characteristics and operating temperature, fuel cells are classed as proton exchange membrane FCs, solid oxide FCs, direct methanol FCs, alkaline FCs, molten carbonate FCs, and phosphoric acid FCs. FCs are used in both commercial and research & development applications. Common stack size, theoretical cell voltage, operating temperature, electrical efficiency, benefits, and downsides are used to classify FC features [18]. In this environment, FCs are used in distributed generation, mobile power, backup power, military, space, and vehicle applications. Low temperature and pressure PEMFCs are the most used FCs in vehicle applications because of their high power density, lower working temperature (60–80°C), and reduced corrosion than other FCs [18].

In the construction of fuel cell hybrid electrical vehicles (FCEVs), fuel cell vehicles (FCs) are coupled to electric motors via controlled electronic interfacing components [19]. The basic components of traditional FCEVs are a voltage regulation converter, motor drive, electric motor, and auxiliary energy generation units [20]. For interfacing components and energy management algorithms, FCEVs vehicles have a variety of configuration topologies [21]. The powertrain structures, voltage regulation topologies, motor drive converters, and energy management technologies can all be used to classify FCEVs. In the operation of FCEVs, the FC stack feeds energy to the dc-bus and maintains the required DC bus voltage [22]. The FC is then connected directly to the Unidirectional DC-DC converter (UDC) as a system element to maintain the dcbus voltage and send the energy generated for vehicle propulsion to the motor drive converter. A DC-AC converter checks the motor speed and torque for safe operation. Finally, the drive controller is in charge of monitoring the electric motors as they convert electrical energy into kinetic energy [23].

FCs have a higher energy density and efficiency than other power sources such as photovoltaics, batteries, ultra capacitors, and super conducting magnetic energy storage. Because of its modular design, FCs are also suitable for electric vehicle applications. Furthermore, FC has a 20–30 year lifespan [24]. As a portable/rechargeable energy storage system, the battery is also a preferred power source for FCEV hybridization. However, it has a short lifespan and is only useful for a short length of time [25]. Ultra capacitors (UC) are a type of storage element that can be used in FCEV applications to increase the dynamic response of the system. Photovoltaic (PV) is a gadget that generates energy, however it is too large to carry. The output of super conductive magnetic energy storage (SMES) generates a lot of power, however it has a low energy density. Short-duration energy storage is also included in SMES, albeit at a high expense [26]. Based on this, several hybridization topologies are recognized in the literature. Full FC, partial FC, and hybrid FC cars are classified as FC + battery hybridization, FC + UC hybridization, FC + battery + UC hybridization, FC + battery + PV, FC + flywheel hybridization, and FC + SMES [18]. FC + battery + PV, FC + battery + PV, FC + flywheel hybridization, and FC + SMES are all examples of FC-powered cars.

The FCEV scheme clearly shows that this topology's energy generation is exclusively dependent on the FC stack. It simple construction includes a fuel tank, FC stack, DC-DC power converter, inverter, and electric motor [27]. These cars feature a long driving range, a fast charging time, high efficiency, cold start capabilities, silent operation due to the lack of mechanical components, energy supply continuity, and low emissions [27]. Full FCEVs are a suitable fit for low-speed vehicles including forklifts, busses, airline vehicles, trams, and marine vehicles. The combination of FC + battery units is the most common topology in FCEV hybridization [18]. A unidirectional DC-DC converter (UDC) connects FC to the DC bus, while a bidirectional DC-DC converter connects the battery to the DC bus. In the operating procedure of FC + battery hybridization, an initial start-up with the battery is provided to avoid the FC running in the low-efficiency zone. As a result, a huge amount of current is generated to start the electric motor [25]. When the car is turned on for the first time, the FC is activated to keep the electric motor going. After then, the battery is charged according to the charge status criteria. The UC only allows FC to be utilized in emergency situations to meet transient power demands. UC, on the other hand, has a low energy density and is not used to give energy on a long-term basis [28].

In contrast to earlier hybridization topologies, FC + battery + UC hybridization has a primary energy source (FC) and two secondary energy sources (battery and UC) (battery and ultra capacitor). In this design, the FC is connected to the DC bus through a one-way DC-DC converter. The energy storage units, battery and UC, are connected to the DC bus by bidirectional DC-DC converters (BDCs). This architecture combines the advantages of FC + battery and FC + UC systems to provide continuous energy while also boosting FC dynamic response during transient events [29]. In recent years, PV panels have been incorporated with FC-based electric vehicles for hybridization. In FC + battery + PV hybridization, PV panels generate DC voltage that is coupled to the DC bus via a unidirectional converter. The FC is the primary energy source in an FC + battery + PV system, with the PV panel acting as a backup. Both the FC and PV busses are connected to the DC bus by unidirectional converters. PV panels generate varying amounts of power based on the intensity of solar radiation, the temperature, and the sun's direction. As a result, the PV electricity generated is fed directly into the electric motor or is used to charge the battery [30].

FC+ flywheel hybridization is similar to the preceding approach in that the FC serves as the major energy source and the flywheel, rather than batteries, serves as an energy storage method. Flywheels and generators are connected to store energy

#### *Zero Emission Hydrogen Fuelled Fuel Cell Vehicle and Advanced Strategy on Internal… DOI: http://dx.doi.org/10.5772/intechopen.102057*

mechanically with a high rotating speed and transform that mechanical energy into electricity when EM requires a lot of it. Flywheels have a faster charging capability, higher efficiency, and higher power rating than batteries [30]. Flywheels are also environmentally friendly, as they operate over a wide temperature range, have a big energy storage capacity, and have a long lifespan [66]. There are three types of static FC models accessible in the literature. Chamberlin-Kim and Amphlett, Larminie, and Dicks models [31] are examples. The most common static model published in the literature is the Amphlett model, which is based on Nernst and Tafel equations. This model takes into account physical parameters like as pressure, temperature, and concentration. The other static model is the Larmine and Dicks model. This model calculates the FC voltage–current characteristic using empirical equations. This model yields the FC voltage versus current amplitude curve. Three zones can be found in this curve. The three zones are electrochemical activation, linear part, and gas diffusion kinetics [32]. The third static FC model is the Chamberlin-Kim model. In this approach, the FC voltage is described in terms of current density. In addition, the fuel-oxidant rate, local temperature, and humidity all affect five factors in this model [32].

Dynamic modeling of FC is described in the literature such as the impedance model, Becherif-Hissel model, and Dicks-Larminie model have been reported [33]. Layer capacitance, diffusion impedance, and ions transport, membrane, and contact resistances are all included in the impedance model [34]. The Nernst voltage, ohmic polarization, concentration, and activation are all modeled in the Dicks-Larminie model. A voltage supply, two resistances, and a capacitor make up this model. The Nernst voltage is demonstrated via the voltage source. The resistances represent electron-hydrogen flow and activation-concentration losses. The charge layers are represented by the capacitance. The pneumatic feature is taken into account in the Becherif-Hissel model to obtain the comparable model for electrical components. The conservation of mass, energy, and charge is taken into account in pneumatic properties [35].
