**2.1 Types of electric vehicles**

In this sector five sorts of electric vehicles; HEV, PHEV, BEV, FCEV, and SEV, are discussed as follows:


Powertrain configurations of EVs are illustrated in **Figure 4**, and it indicates that an energy storage device is necessary for specific functions, for instance, demand response, transmission, flexible generation, improve operational practices and providing high energy density [25, 26].

Even if electric vehicles have more than their share of advantages, it is worth noting that they still have their drawbacks. It is imperative to recognize that EVs are usually changing and their technologies are evolving if considering EVs' pros and cons. HEV has an advantage in component availability, but it takes higher initial

**Figure 4.** *The powertrain configurations of EVs.*

#### *Hydrogen Fuel Cell Implementation for the Transportation Sector DOI: http://dx.doi.org/10.5772/intechopen.95291*

cost. Furthermore, its two power trains build complexity of configurations and significant transmission energy loss. The characters of PHEV are similar to HEV, however, high cost of its batteries and battery replacement and added weight are taken into consideration. SEV does not have speed or power that regular cars have, and its operation is relevant to weather dependency. It seems likely that BEV is in the spotlight, nevertheless, there are some cons. It gives short distance range, while battery technology and public recharging infrastructure are needed to be improved these are the reasons that Toyota has long maintained that hydrogen fuel cell technology could be a zero-emission solution across a broad spectrum of vehicle types? Do FCEVs have a future?

Despite the development of hydrogen fuel cell cars started in 1966 with GM's Electrovan, they remain low in volume, expensive to produce, and restricted to sales in the few regions that have built hydrogen fueling stations. A big BEV manufacturer disagrees with this idea, and the CEO of the company described the fuel cell technology as a mind-bogglingly stupid technology. Why is Toyota still trying to make the fuel cell happen? Some scientists predicted that people would be able to drive FCEVs without any problems and to refuel 800 km of range in 2–3 minutes without any local emissions. BEVs maybe therefore only a temporary transitional technology.

Authors would like to provide readers with concise information that may help answer these questions. During PEMFC operations, hydrogen permeates through the anode via a bipolar plate and interacts with the catalyst for producing electrons and protons. The electrons are conducted via electrically conductive materials (catalyst, gas diffusion layers, bipolar plates, and current collectors) through an external circuit to the cathode, while the protons are simultaneously transferred via an ionic route through a polymer electrolyte membrane (Nafion membrane) to the cathode. At the cathode, oxygen permeates to the catalyst surface where it reacts with the protons and electrons with properly hydrated situations. Subsequently, the products of the fuel cell reactions are water, electricity and heat [27].

### **2.2 Filling fuel of FCEVs**

FCEVs are charged using compressed hydrogen gas, and the hydrogen is drawn from an onboard tank and fuses it chemically with oxygen to create water. The BEV battery is recharged by connecting it to the electrical grid through a connector system. With 5 minutes for one tank filling, refuelling hydrogen is significantly faster than charging a BEV that is around 3 hours [28]. Additional 5 to 10 minutes are spent for a hydrogen pump to be ready for refuelling after a few refuelling operations until the fueling pressure is built up again. People have to drive FCEVs to a hydrogen gas station for refuelling, while BEV can be either charged at home or a station. As known. Hydrogen fuel stations are rare since construction costs of hydrogen stations are expensive. The costs are expected to be decreased via largescale deployment and standardization. Moreover, a centralized control center for the hydrogen station is envisioned, accordingly dropping the operating costs.

Hydrogen production principally composes of 2 approaches; stream reforming and electrolysis [29]. Steam reforming is currently one of the most pervasive processes for hydrogen production. This technique gains advantages from highefficiency production and low operational and production costs. Reactants used for the process are natural gas and lighter hydrocarbons, methanol, and other oxygenated hydrocarbons [30]. Electrolysis is a promising option for hydrogen production from a renewable resource such as water. The process uses electricity to split water into hydrogen and oxygen [30]. For charging the battery and fueling hydrogen via electrolytic cell, both come with energy and efficiency losses. In the case of BEV,

an electrical grid provides AC currents, while the batteries discharge DC currents. Quick charging efficiency is around 92%. If BEV runs with an AC motor, the inverter efficiency would be 90%. Also, a lithium-ion battery can lose energy due to current leakage, so a good estimate for charging a lithium-ion battery is about 90%. All these factors combined lead to 75–80% of total efficiency for charging BEV. In the case of FCEV, rectifier requires AC current from the electrical grid to drive the electrolysis, thus conversion efficiency would be about 92%. We also need to convert DC produced from fuel cell to power the AC motor with inverter efficiency 90%. Finally, the efficiency of the motor must be considered for both fuel cell and battery, currently around 90–95%. However, storage hydrogen into cylinder and transportation must be included for fuel cell efficiency losses. Once the hydrogen is produced and compressed into liquid or gas, available hydrogen infrastructure requires as hydrogen be able to be delivered from where it is produced to the point of end-use. Since hydrogen is exceedingly low density as a gas and liquid, to achieve satisfactory energy density, actual density must be increased. There are two choices, compressing and liquifying hydrogen, for increasing the density. Hydrogen can be compressed to 790 times atm pressure, but that takes energy nearby 13% of the total energy content of the hydrogen [29]. Hydrogen can be turned into liquid cryogenically. Hydrogen is liquified by decreasing its temperature to −253°C with 40% of an efficiency loss. The benefit of hydrogen liquefaction is that a cryogenic hydrogen cylinder is much lighter than a cylinder holding pressurized hydrogen. In conclude, pressurization is the better option for efficiency losses. Focusing on hydrogen transportation, hydrogen is being transported by truck or pipeline, where know energy loss from 10% up to 40%. In the worst case, the total efficiency of FCEV may be approximately 20%, while the BEV efficiency could be 56% [29]. Another weakness of FCEVs is the price per kg of hydrogen. The FCEV named Honda Clarity gets about 589 km with 5.5 kg of hydrogen, so that would cost about \$0.14/km. In contrast, Tesla Model 3 (BEV) employs \$0.03/km or \$0.20/ kWh of energy. Noted, the information relates to the US hydrogen price in 2018 that was \$15/kg.
