ELECTRIC VEHICLES FEATURE
Electrifying the vehicle market B
Simone Bruckner, managing director of power resistor manufacturer, Cressall Resistors, explains how the electric vehicle market will meet the drive for efficiency
y 2040, the government’s proposed ‘Road to Zero’ emissions plan will
require each new car sold in the UK to have an electric driving range of at least 50 miles. With electric vehicle (EV) capabilities switching from an environmentally kinder preference to a mandatory requirement, the industry will have to electrify more than just commercial vehicles. With the potential to reduce emissions
in the largest-emitting sector, international market trends suggest that electric cars and vans will reach price equivalency with internal combustion engine (ICE) vehicles by the mid-2020s, and that EV sales will overtake petrol and diesel engines by the late 2030s. Despite this burgeoning expected
growth, there are still some important questions that need to be answered surrounding just how manufacturers can guarantee efficiency levels that can outperform those of traditional vehicles.
GOING PUBLIC Urban electric buses are surpassing the growth of every other EV segment and constitute the fastest-growing part of the EV market. In China, the once quaint city of
Shenzhen has become a megalopolis. Over 40 years, Shenzhen’s population has accelerated from 30,000 citizens to over 12 million. In line with this rapid transformation, the city began introducing electric buses in 2009 to combat rising air pollution, and it became the first city to electrify all of its public buses. Over the next decade, bus fleets worldwide are predicted to reap the benefits of electrified transport. However, the e-bus phenomenon presents cities with some major
challenges: namely technological uncertainty, large up-front investment, and the need for new capabilities. It is therefore important that the technology is in place to transform potential into reality. This may include building IT systems that can monitor and handle a potentially complex web of timetables and charging schedules.
BEAR THE LOAD There is also concern over how other heavier vehicles will be electrified. In 2017, Tesla announced that its Semi heavy electric truck would be ready for production by 2020. With pledges of a 500-mile driving range and solar-powered ‘Megacharger’ stations, the company certainly has a lot to deliver. Many are speculating the specifications
of the Tesla Semi, especially its weight. If powering the EV requires several electric motors, this weight would be roughly comparable to that of a diesel engine. With the addition of the truck’s battery weight, the components inside EVs must be refined so that they can bear the load of this extra mass without it impacting efficiency. Despite slick marketing campaigns and
captivating master plans, there is still a long way to go before we see a complete overhaul of heavy vehicles. To turn ambitions of electric heavy vehicles into reality, we must assess the components going into them - and the focus shouldn’t solely be on batteries.
REGENERATION GAME Instead of internal combustion engines, electric vehicles use a braking chopper to convert the energy generated by high speed braking. Urban drive cycles have a considerable amount of acceleration and
decelerating periods due to traffic control around towns and cities. While braking, a car’s motor continues to spin even though the vehicle is trying to slow down, creating excess energy. Integrating a braking resistor allows
this otherwise wasted energy to be dissipated as heat and recovered to warm the vehicle’s cabin or to regenerate the kinetic energy to improve efficiency.
WATER AND AIR To increase a braking resistor’s dissipation capability, it’s important that the component is prevented from overheating. From Cressall’s experience, the challenge of managing temperature is critical when ensuring EV efficiency, and standard electrical items may not always fulfil this requirement. Most brake resistors are encased in
a frame to create a safe distance between surrounding components. These frames feature either cooling fans or liquid coolants. Air cooling is a traditionally common
cooling method, as its fan technology is able to withstand a significant amount of wear and tear without malfunctioning. This method of dissipating heat does,
however, come with its limitations. Air fans create additional noise, which interferes with the quiet running that is typically one of an EV’s benefits. Fans are further limited by their reliance on ambient temperatures to cool down components, which impacts their consistency. On the other hand, water-cooled
resistors, such as Cressall’s EV2, are able to deliver cooling where fans often fall short. Pipes containing a liquid coolant circulate around an enclosure and out of the device to cool components via heat exchange. As the water can be stored in pipes at temperatures below the application’s ambient level, cooling can happen faster and with greater reliability. If the planet is to move away from
petrol and diesel, all vehicles on our roads need to undergo an upgrade. For this to happen, vehicle technology needs to keep pace. It isn’t all about batteries. Other components, such as braking resistors, must also be perfected to maximise the drive for greener roads.
Cressall Resistors
cressall.com ELECTRICAL ENGINEERING | OCTOBER 2019 7
Page 1 |
Page 2 |
Page 3 |
Page 4 |
Page 5 |
Page 6 |
Page 7 |
Page 8 |
Page 9 |
Page 10 |
Page 11 |
Page 12 |
Page 13 |
Page 14 |
Page 15 |
Page 16 |
Page 17 |
Page 18 |
Page 19 |
Page 20 |
Page 21 |
Page 22 |
Page 23 |
Page 24 |
Page 25 |
Page 26 |
Page 27 |
Page 28 |
Page 29 |
Page 30 |
Page 31 |
Page 32 |
Page 33 |
Page 34 |
Page 35 |
Page 36 |
Page 37 |
Page 38 |
Page 39 |
Page 40 |
Page 41 |
Page 42 |
Page 43 |
Page 44 |
Page 45 |
Page 46 |
Page 47 |
Page 48 |
Page 49 |
Page 50 |
Page 51 |
Page 52 |
Page 53 |
Page 54 |
Page 55 |
Page 56 |
Page 57 |
Page 58 |
Page 59 |
Page 60
