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Hydrogen, Or Batteries, That Is The Question: Hyundai Elec City Bus

2020-08-26

The advantages of eco-friendly cars are further maximized in the field of commercial vehicles. Let's look deeper into the characteristics of eco-friendly commercial vehicles through the Hyundai Electric Elec City and hydrogen-powered Elec City.

‘Green commercial vehicles’ are gaining social awareness every day. Unlike conventional diesel commercial vehicles, eco-friendly commercial vehicles with electric powertrain do not emit any pollutants (PM, NOx, etc.) during operation. In addition, commercial vehicles travel much more than private vehicles, so they get to affect our environment much more. Hyundai Motor Company is entering an era of eco-friendly commercial vehicles as it mass-produces its electric bus called Elec City started in 2017.

Hyundai Elec City: Perfect for Eco-friendly City Tours

The electric Elec City houses a fully integrated electric axle drive system and water-cooled battery system for its energy efficiency.

In fact, it is quite hard for EVs to increase their ranges. As the battery capacity increases, its weight also increases at the same time, increasing the burden on electric motors and reducing energy efficiency. It is most efficient with proper battery capacity, considering a heavier battery does not always mean increased range. Due to these technical characteristics, electrification is usually better for smaller and lighter commercial vehicles than heavier ones.

The electric Elec City, which runs its motor using the power stored in batteries, has optimized performance for urban driving and city bus use. This is because it minimizes energy loss and maximizes power and driving efficiency by applying 256 kWh high-capacity lithium-ion polymer batteries and a 240-kW, fully integrated electric axle drive system. The body weight was also reduced by a semi-monocoque integral body design so that the battery weight does not affect the efficiency. It partially integrated the frame and room of the vehicle to curb unnecessary weight increase. As a result, the electric city has a curb weight of only 12.1 tons (12,140 kg) despite its large body with passenger capacity. This is about 95 kilograms lighter than the existing ultra-low-floor CNG (Compressed Natural Gas) bus (Curb weight can vary depending on trims).

Electric Bus: Easy access to stations + Cost-efficiency

Electric buses are also convenient in terms of recharging; this is due to their regular rechargings. City buses do not change their routes or recharge suddenly. This means that their efficiency can be guaranteed when charging stations are built in the terminal stations. Among various commercial electric vehicles – buses, trucks, and special cars, – the electric buses, Elec City, were the first to be mass-produced for this reason.

The 256 kWh high-capacity battery is appropriate for routes that consume high amounts of electricity with frequent traffic congestion or slopes, as well as for coach services. It can travel up to 319 kilometers per charge. With regard to regular city bus routes, it allows buses to run for a whole day just with one or two rechargings. Elec City also features a water-cooled heat management system that optimizes the temperature of the battery, hence exceptional durability. This management system uses water to keep the temperature of the battery constant with great efficiency. Thanks to this, the Elec City’s battery, if ran 500,000 kilometers, has a performance of about 70 to 80 percent compared to the new one.

Eco-friendliness and cost-efficiency are also advantages of Elec City. If one CNG bus is replaced by an Elec City, it can reduce carbon dioxide emissions by about 125 tons every year (based on the average range of a regular city bus – 86,000 km/year). This is the same amount of carbon dioxide absorbed by about 19,000 30-year-old pine trees.

The next-generation green commercial vehicle : Hydrogen-powered Elec City bus

Hydrogen-powered Elec City is an eco-friendly commercial vehicle with a hydrogen fuel cell system.

The company then unveiled its hydrogen-powered Elec City bus. This houses a hydrogen fuel cell system in the existing electric city. Both buses run on electricity, except for the driving principle; the hydrogen-powered Elec City bus that stores hydrogen fuel in the tank runs its motor through a chemical reaction between stored hydrogen and atmospheric oxygen. So, apparently, the characteristics of the two vehicles are mostly due to the difference between the battery and the hydrogen fuel cell system. An FCEV generates and stores electrical energy all by itself through the fuel cell system, which leads to faster charging time and improved operation efficiency comparable to the internal combustion engines.

The latest hydrogen-powered Elec City bus is equipped with a hydrogen fuel cell system for enhanced performance and durability. The 180 kW high-capacity hydrogen fuel cell system, which consists of two 90 kW hydrogen fuel cells, is equipped with a durable hydrogen diffusion layer and an electrolyte membrane. The maximum output of 180 kW with improved cost-efficiency demonstrates an optimized driving force even in hilly road conditions in Korea. There are five hydrogen tanks in the roof, storing a total of 34.5 kg of hydrogen. It can travel over 434 km when fully charged, according to the Seoul Mode simulation system.

The hydrogen fuel tank is covered with carbon fiber composite materials that have more than six times the strength of steel and is applied with nylon inner skin that minimizes hydrogen transmission to withstand strong internal and external impact. It also has proved itself to be safe enough by passing fourteen tests, including falling weight tests, impact testing at high pressure, flame tests, and bullet impact tests.

Elec City purifying air while driving

Just like the other FCEVs, the oxygen necessary to react with hydrogen for the Elec City bus is drawn from the atmosphere. Such air drawn into the FCEV passes through an air purification system that cleans it of particulates and other unwanted matter, leaving the air cleaner. This is necessary for keeping the cell stack from pollutants. In a way, it has an atmospheric ‘scrubbing’ effect.

he Elec City buses emit nothing but clean air.

In addition, the latest hydrogen-powered Elec City buses are less limited by topography when it comes to installing charging stations. While rapid charging stations require high-voltage power lines, hydrogen fuel can be supplied regularly through delivery vehicles that we use for carrying gasoline or diesel. In addition, hydrogen charging infrastructures can be easily established by using the current CNG charging stations.

The reciprocal: electric Elec City and the hydrogen-powered Elec City

The electric Elec City and the hydrogen-powered Elec City are both offering the best eco-friendly mobility solution based on each one’s technical characteristics. For example, electric Elec City is more convenient when operating in the city center based on the already built electric charging infrastructure. The hydrogen-powered Elec City is expected to be more effective when running in small cities where building charging stations is relatively hard, and for long-distance travel.

Commercial EVs and FCEVs have characteristics that cover each other’s shortcomings. The Hyundai Motor Group plans to build a lineup of 17 eco-friendly electrified commercial models, including 7 EVs and 10 FCEVs by 2025. Based on the company’s eco-friendly technology that would enhance such sustainability, it plans to contribute to public transportation and logistics industries as well.