Ask Joe Mechanic - Electric Vehicles (Part 2)

In the United States, General Motors (GM) ran in several cities a training program for firefighters and first responders to demonstrate the sequence of tasks required to safely disable the Chevrolet Volt’s powertrain and its 12 volt electrical system, which controls its high-voltage components, and then proceed to extricate injured occupants. The Volt's high-voltage system is designed to shut down automatically in the event of an airbag deployment, and to detect a loss of communication from an airbag control module. GM also made available an Emergency Response Guide for the 2011 Volt for use by emergency responders. The guide also describes methods of disabling the high voltage system and identifies cut zone information. Nissan also published a guide for first responders that details procedures for handling a damaged 2011 Leaf at the scene of an accident, including a manual high-voltage system shutdown, rather than the automatic process built-in the car's safety systems.

 Great effort is taken to keep the mass of an electric vehicle as low as possible to improve its range and endurance. However, the weight and bulk of the batteries themselves usually makes an EV heavier than a comparable gasoline vehicle, reducing range and leading to longer braking distances; it also has less interior space. However, in a collision, the occupants of a heavy vehicle will, on average, suffer fewer and less serious injuries than the occupants of a lighter vehicle; therefore, the additional weight brings safety benefits despite having a negative effect on the car's performance. An accident in a 2,000 lb (900 kg) vehicle will on average cause about 50% more injuries to its occupants than a 3,000 lb (1,400 kg) vehicle. In a single car accident and for the other car in a two-car accident, the increased mass causes an increase in accelerations and hence an increase in the severity of the accident. Some electric cars use low rolling resistance tires, which typically offer less grip than normal tires. Many electric cars have a small, light and fragile body, though, and therefore offer inadequate safety protection. The Insurance Institute for Highway Safety in America had condemned the use of low speed vehicles and "mini trucks," referred to as neighborhood electric vehicles (NEVs) when powered by electric motors, on public roads.

At low speeds, electric cars produced less roadway noise as compared to vehicles propelled by internal combustion engines. Blind people or the visually impaired consider the noise of combustion engines a helpful aid while crossing streets, hence electric cars and hybrids could pose an unexpected hazard. Tests have shown that this is a valid concern, as vehicles operating in electric mode can be particularly hard to hear below 20 mph (30 km/h) for all types of road users and not only the visually impaired. At higher speeds, the sound created by tire friction and the air displaced by the vehicle start to make sufficient audible noise.

The Government of Japan, the U.S. Congress, and the European Parliament passed legislation to regulate the minimum level of sound for hybrids and plug-in electric vehicles when operating in electric mode, so that blind people and other pedestrians and cyclists can hear them coming and detect from which direction they are approaching. The Nissan Leaf was the first electric car to use Nissan's Vehicle Sound for Pedestrians system, which includes one sound for forward motion and another for reverse. As of March 2013, most of the hybrids and plug-in electric cars available in the United States make warning noises using a speaker system. The Tesla Model S is one of the few electric-drive cars without warning sounds, because Tesla Motors is awaiting the National Highway Traffic Safety Administration final rule.

Far and away, the largest concern for electric vehicles is their batteries. The limitations of range, availability of charging, safety, lifespan, cost of replacement are just some of the things considered regarding batteries.  Finding the economic balance of range against performance, energy density, and accumulator type versus cost challenges every EV manufacturer. While most current highway-speed electric vehicle designs focus on lithium-ion and other lithium-based variants a variety of alternative batteries can also be used. Lithium-based batteries are often chosen for their high power and energy density but have a limited shelf-life and cycle lifetime which can significantly increase the running costs of the vehicle. Variants such as Lithium iron phosphate and Lithium-titanate attempt to solve the durability issues with traditional lithium-ion batteries.

Other battery technologies include:

• Lead acid batteries are still the most used form of power for most of the electric vehicles used today. The initial construction costs are significantly lower than for other battery types, and while power output to weight is poorer than other designs, range and power can be easily added by increasing the number of batteries. NiCd - Largely superseded by NiMH
• Nickel metal hydride (NiMH)
• Nickel iron battery - Known for its comparatively long lifetime and low power density

Several battery technologies are also in development such as:

• Zinc-air battery
• Molten salt battery
• Zinc-bromine flow batteries or Vanadium redox batteries can be refilled, instead of recharged, saving time. The depleted electrolyte can be recharged at the point of exchange, or taken away to a remote station.

Unlike vehicles powered by fossil fuels, BEVs are most commonly and conveniently charged from the power grid overnight at home, without the inconvenience of having to go to a filling station. Charging can also be done using a street or shop charging station.  The electricity on the grid is in turn generated from a variety of sources; such as coal, hydroelectricity, nuclear and others. Power sources such as roof top photovoltaic solar cell panels, micro hydro or wind may also be used and are promoted because of concerns regarding global warming.

                  
 Most electric cars have used conductive coupling to supply electricity for recharging after the California Air Resources Board settled on the SAE J1772-2001 standard as the charging interface for electric vehicles in California in June 2001. In Europe the ACEA has decided to use the Type 2 connector from the range of IEC_62196 plug types for conductive charging of electric vehicles in the European Union as the Type 1 connector (SAE J1772-2009) does not provide for three-phase charging.  Another approach is inductive charging using a non-conducting "paddle" inserted into a slot in the car. Delco Electronics developed the Magne Charge inductive charging system around 1998 for the General Motors EV1 and it was also used for the Chevrolet S-10 EV and Toyota RAV4 EV vehicles.

Reports emerged in late July 2013 of a significant conflict between the companies responsible for the two types of charging machines. The Japanese-developed CHAdeMO standard is favored by Nissan, Mitsubishi, and Toyota, while the Society of Automotive Engineers’ (SAE) International J1772 Combo standard is backed by GM, Ford, Volkswagen, and BMW. Both are direct-current quick-charging systems designed to charge the battery of an electric vehicle to 80 percent in approximately 20 minutes, but the two systems are completely incompatible. In light of an ongoing feud between the two companies, experts in the field warned that the momentum of the electric vehicle market would be severely affected. Richard Martin, editorial director for clean technology marketing and consultant firm Navigant Research, stated:

“Fast charging, however and whenever it gets built out, is going to be key for the development of a mainstream market for plug-in electric vehicles. The broader conflict between the CHAdeMO and SAE Combo connectors, we see that as a hindrance to the market over the next several years that needs to be worked out. Newer cars and prototypes are looking at ways of dramatically reducing the charging times for electric cars. The BMW i3 for example, can charge 0-80% of the battery in under 30 minutes in rapid charging mode.”

                  
 More electrical power to the car reduces charging time. Power is limited by the capacity of the grid connection, and, for level 1 and 2 charging, by the power rating of the car's on-board charger. A normal household outlet is between 1.5 kW (in the US, Canada, Japan, and other countries with 110 volt supply) to 3 kW (in countries with 230V supply). The main connection to a house may sustain 10, 15 or even 20 kW in addition to "normal" domestic loads—although, it would be unwise to use all the apparent capability—and special wiring can be installed to use this.  As examples of on-board chargers, the Nissan Leaf at launch has a 3.3 kW charger and the Tesla Roadster can accept up to 16.8 kW (240V at 70A) from the High Power Wall Connector. These power numbers are small compared to the effective power delivery rate of an average petrol pump, about 5,000 kW.

Even if the electrical supply power can be increased, most batteries do not accept charge at greater than their charge rate ("1C"), because high charge rates have an adverse effect on the discharge capacities of batteries. Despite these power limitations, plugging in to even the least-powerful conventional home outlet provides more than 15 kilowatt-hours of energy overnight, sufficient to propel most electric cars more than 70 kilometres (43 mi).  Using regenerative braking, a feature, which is present on many hybrid electric vehicles, approximately 20 percent of the energy usually lost in the brakes, is recovered to recharge the batteries.

An alternative to quick recharging is to exchange a discharged battery or battery pack for a fully charged one, saving the delay of waiting for the vehicle's battery to charge. Battery swapping is common in warehouses using electric forklift trucks.  The concept of exchangeable battery service was first proposed as early as 1896 in order to overcome the limited operating range of electric cars and trucks. The concept was first put into practice by Hartford Electric Light Company through the GeVeCo battery service and was initially available for electric trucks. Both vehicles and batteries were modified to facilitate a fast battery exchange. The service was provided between 1910 and 1924 and during that period covered more than 6 million miles. A rapid battery replacement system was implemented to keep running 50 electric buses at the 2008 Summer Olympics.

Tesla Motors designed its Model S to allow fast battery swapping. In June 2013, Tesla announced their goal to deploy a battery swapping station in each of its supercharging stations.  At a demonstration event, Tesla showed that a battery swap operation with the Model S takes just over 90-seconds, about half the time it takes to refill a gasoline-powered car.  The first stations will be deployed along Interstate 5 in California where, according to Tesla, a large number of Model S sedans make the San Francisco-Los Angeles trip regularly.  The Washington, DC to Boston corridor, will follow these stations. Each swapping station will cost $500,000 USD and will have about 50 batteries available without requiring reservations. The service would be offered for the price of about 15 US gallons (57 l; 12 imp gal) of gasoline at the current local rate, around $60 to $80 USD at June 2013 prices.

 Battery life should be considered when calculating the extended cost of ownership, as all batteries eventually wear out and must be replaced. The rate at which they expire depends on the type of battery technology and how they are used — many types of batteries are damaged by depleting them beyond a certain, optimal level.  Lithium-ion batteries degrade faster when stored at higher temperatures.

The future of battery electric vehicles depends primarily upon the cost and availability of batteries with high specific energy, power density, and long life, as all other aspects such as motors, motor controllers, and chargers are fairly mature and cost-competitive with internal combustion engine components. Diarmuid O'Connell, VP of Business Development at Tesla Motors, estimates that by the year 2020 30 percent of the cars driving on the road will be battery electric or plug-in hybrid.

Nissan CEO Carlos Ghosn has predicted that one in 10 cars globally will run on battery power alone by 2020. Additionally, a recent report claims that by 2020 electric cars and other green cars will take a third of the total of global car sales. It is estimated that there are sufficient lithium reserves to power four billion electric cars.

As of November 2013, the number of mass production highway-capable all-electric passenger cars and utility vans available in the market is limited to about 25 models. Most electric vehicles in the world roads are low-speed, low-range neighborhood electric vehicles (NEVs) or electric quadricycles. Pike Research estimated there were almost 479,000 NEVs on the world roads in 2011. The two largest NEV markets in 2011 were the United States, with 14,737 units sold, and France, with 2,231 units. The Renault Twizy all-electric heavy quadricycle, launched in Europe in March 2012 and with global sales of 9,020 units through December 2012, became the best selling plug-in electric vehicle in Europe for 2012. The top selling markets were Germany with 2,413 units, France with 2,232 units, and Italy with 1,545 units sold in 2012. As of November 2013, global Twizy sales totaled 11,879 units.

The world's top selling highway-capable electric car ever is the Nissan Leaf, released in December 2010, with global sales of over 92,000 units delivered by early December 2013. All-electric models scheduled for market launch in 2014 include the Volkswagen e-Golf, Mercedes-Benz B-Class Electric Drive, Mercedes-Benz SLS AMG Electric Drive, Tesla Model X, and the limited production Detroit Electric SP.01.

As of September 2013, over 60,000 all-electric cars have been sold in the U.S. since 2008, led by the Nissan Leaf, with 35,588 units, followed by the Tesla Model S with 16,251 units, and the Ford Focus Electric with 2,028 units sold through September 2013. Accounting for plug-in hybrid electric cars sold since 2010 (about 80,000), the United States has the largest fleet of plug-in electric vehicles (PEVs) in the world, with over 140,000 highway-capable plug-in electric cars sold through September 2013. A total of 17,800 plug-in electric cars were delivered during 2011, more than 53,000 during 2012, and over 67,700 units during the first nine months of 2013. PEV sales during the first nine months of 2013 represented a 0.58 percent market share of total new car sales, up from of 0.37 percent in 2012, and 0.14 percent in 2011.

                  
 The Chevrolet Volt is the top selling plug-in hybrid, with 48,218 units, followed by the Toyota Prius Plug-in Hybrid with 20,724 units, and the Ford C-Max Energi with 6,668 units sold through September 2013. During the first nine months of 2013 sales were led by the Chevrolet Volt with 16,760 units, followed by the Nissan Leaf with 16,076 cars, and the Tesla Model S with about 13,500 units. August 2013 is the best month on record for U.S. plug-in vehicle sales, with more than 11,000 units delivered, representing a market share of 0.76 percent of new car sales.

California, the largest United States car market, is also the leading plug-in electric-drive market in the country. About 40 percent of the segment's nationwide sales during 2011 and 2012 were made in California, while the state represents about 10 percent of all new car sales in the country.  From January to May 2013, 52 percent of American plug-in electric car registrations were concentrated in five metropolitan areas: San Francisco, Los Angeles, Seattle, New York and Atlanta.

 During 2011, all-electric cars (10,064 sold) oversold plug-in hybrids (7,671 sold), but increased Volt sales, together with the introduction of the Prius PHV and the Ford C-Max Energi, allowed plug-in hybrids to take the lead over pure electric cars during 2012, with 38,584 PHEVs sold versus 14,251 BEVs. During the first nine monts of 2013, sales of pure electric cars (35,261) outsold plug-in hybrids (32,718), due to large sales of the Tesla Model S and Nissan Leaf during 2013. During the first half of 2013, all-electric vehicle sales also outsold plug-in hybrids in California. During this period a total of 15,444 new plug-in electric vehicles were sold in the state, with plug-in hybrids representing a market share of 0.7 percent of new vehicle sales, while battery electric vehicle market share was 1.1 percent.

Hopefully, this wealth of information on hybrid and full electric vehicles will help you make your decision if one of these vehicles is in your future. We will also look at diesel engine vehicles, as there have been a lot of advancements in diesel technology and new model introductions in recent years.