Battery electric vehicles and hybrid plug-in electric vehicles are considered critical technologies—especially in urban environments, where they address concerns about energy costs, energy independence and environmental damage, said Rajesh Uppal, director and founder of International Defense, Security & Technology, Inc.
Because of their various benefits, the transition to electric cars is imminent. But the speed of adoption remains debatable. Many bold claims have been made about when the tipping point will come. Some believe it will be no more than 10 years from now, while others are more cautious, citing 2040 as a target. As ground transportation in the United States electrifies, the impact on automotive lubricants will be significant.
According to government data, there are about 275 million passenger cars and light trucks on U.S. roads. For the past several years, annual new car and light truck sales have hovered around 16.5 million.
Those sales are partially offset by vehicles being removed from the market. About 15 million vehicles were scrapped last year in the U.S. Presently, the average age of cars and light trucks surpasses 12 years, and that number continues to increase. Further, vehicles 16 years old and older are becoming more common. IHS Markit estimates that these aged vehicles represented 35 million vehicles on the road in 2002 and are projected to account for 84 million by 2023.
Why are these old cars sticking around? Two factors weigh heavily. First, cars and light trucks are expensive. Statista reports that the average cost of a new car or light truck was $34,450 in 2016 and rose to $38,960 by 2020—a 13% increase over the period. The second factor is the increased quality and durability of modern vehicles. While 100,000-mile mechanical life was believed to be good fifty years ago, now this number is expected to be in the 200,000-250,000-mile range.
Transmission design has improved significantly, too. Fifty years ago, there were manual and automatic transmissions. Today, these are joined by dual clutch and constant velocity transmissions, which offer better fuel economy. Vehicles now are almost universally front-wheel drive and more light trucks (including sport utility vehicles) are sold than sedans or minivans.
“As the annual sale of BEVs reaches the 1.4 million mark by 2025, there will be more than 18 million electric cars in the U.S. alone,” said PolicyAdvice, an automobile insurance research group. “By that time, every BEV owner will expect to charge their vehicles at home and outdoors—hence the demand for a more robust charging infrastructure will grow as well.”
Supply Chain Woes Slow Adoption
EV battery costs continue to decrease, but recent materials supply issues have slowed progress. The federal government requires an eight-year minimum warranty on batteries. Most car manufacturers warrant them for 8-10 years. Currently, the cost of a new battery package after the warranty expires is $5,500.
These batteries are not what most people would envision. They are actually boxes with up to fifty individual cells that look a bit like a AA battery. The number of battery packs determines how many kilowatt hours are included.
Other more substantive concerns center on product availability and dependability. Are there enough vehicles available, and how long they can be expected to operate? As of last year, there were about 1.8 million electric vehicles registered in the U.S., according to the International Energy Agency. Both Ford and GM have announced major investments in BEVs. Certainly, production capabilities will increase but are currently hampered by the shortage of microchip and other electronic componentry.
E&E News reported that “the shortage is a result of pandemic-related constraints on supply chains and other factors, and it could prolong the world’s sluggish transition to electric vehicles if chips remain scarce in the coming months.”
Show Me the Money
Dependability of BEVs seems to be satisfactory, if not better than ICE vehicles. Consumer Reports noted that “lifetime fuel and maintenance costs for ICEs are greater than the purchase price. By contrast, BEVs have higher up-front purchase costs, but in the long run they save on operating expenses.” For instance, Tesla recommends transmission fluid changes every 150,000 miles or 12 years, while many ICEs with automatic transmissions require a refresh every 60,000-100,000 miles.
How much money can a BEV save over an ICE? When adjusted to account for federal incentives, BEVs depreciate at the same rate as ICEs in the same class over the first five years of ownership. BEVs are expected to cost less because electric motors and other drivetrain components have fewer moving parts than ICEs. The bottom line, according to a reliability survey of thousands of Consumer Reports members, is that BEV owners generally pay half as much as ICE owners for repairs and maintenance.
One issue that has limited BEV growth in the marketplace is driving range. ICE range is commonly reported as 350-400 miles. BEV range varies greatly but generally lies around 250 miles. Originally, there was concern that American drivers would be uncomfortable with the shorter ranges of BEVs. However, newer vehicles with more efficient and larger battery packs are pushing the range up. Projections are that a 95-kWh battery system could reach the 350-400 mile range.
The unexpected “Deep Freeze” in Texas in February 2021 highlighted another potential trap for BEVs. When temperatures drop too low, battery performance is substantially reduced. Xiaosong Hu, in an article written for Progress in Energy and Combustion Science, noted that ”the overall performance of traction batteries deteriorates significantly at low temperatures due to the reduced electrochemical reaction rate and accelerated health degradation, such as lithium plating.”
Internal battery resistance increases drastically at extreme conditions below 0 degrees Fahrenheit, causing a considerable decrease in power sourcing and sinking capabilities. When the battery is charged at extremely low temperatures, lithium plating at the surface of the anode occurs, resulting in significant capacity loss and even internal short circuits once the growing lithium dendrites pierce the battery separator, Hu said. A cold start-up is typically needed after parking an EV for a long period in cold weather. This results in performance degradation of 30%-40% in lithium-ion batteries and leads to a significant reduction of the driving range.
Infrastructure Comes Up Short
According to the Energy Information Agency, the U.S. produced 4.1 trillion kWh of electricity in 2020, 3.7 trillion kWh of which were sold to end use customers. The sources of electric generation were 60% fossil fuel, 20% nuclear and 20% renewables.
That amount of electricity would be insufficient to support widespread adoption of EVs. As of 2017, the U.S. had about 115,400 fuel delivery stations, according to Statista. While it seems logical that eventually these stations would convert to BEV charging stations, the truth is that electric delivery is much more complicated.
Electric generation is now leaning toward renewable sources. The largest of these is wind, followed closely by hydroelectric and solar. As the need for electricity to charge batteries grows, additional generation capacity will be needed. Wind and solar will most likely be the go-to solutions.
EV Lubricant Requirements
How will EV adoption affect the lubricants industry? A report in Electric Vehicles InSite noted that “electrification of the four-wheeler passenger vehicle fleet may affect the quantities of transmission fluids, greases and other types of lubricants used in automobiles, but the impact of electric vehicles on overall consumption can largely be distilled down to engine oils.” The rate at which BEVs enter the market will determine how quickly the U.S. market for engine oils declines.
Further, hybrid EVs will likely be an interim solution to the need for more fuel efficient, reduced emissions transportation. There will be a continuing need for traditional engine oils for these vehicles, albeit at lower volumes. Additionally, hybrid engine oils must have an increased load carrying feature, since it is likely that the engine will need to be started “on the fly” when the battery charge is exhausted. This will result in some shock loading on the engine.
EV lubricants will also need to have sufficient thermal and electrical properties. Base oil is an excellent insulator, and improved volatility properties, higher viscosity index and lower viscosity are all favored for EV applications. There will be room for such non-traditional base oils as biobased, synthetic (including Group III) and non-hydrocarbon base fluids, like silicone- or glycol-based chemistries.
There will be a need for additive chemistries that enhance load carrying properties without degrading electrical properties. Because there will be greater amounts of copper in EV motors, additive technologies that improve corrosion resistance will be needed. Because of the higher temperatures and the electrical environment, vapor space corrosion inhibition will be vital, too.
Selda Gunsel, vice president global commercial technology at Shell, said that additive innovation and technology developments that will improve the thermal and electrical properties of fluids, is required. Fluids that meet the specific needs of different drivetrain technologies are important, whether it is for hybrids or BEVs, with additive requirements dependent on unique EV hardware setups and the requirements of individual customers.
The lubricants for BEVs will be led by transmission and gear oils. The transmissions in BEVs are more like a two-speed gear box. Since there is no increase in loading as the motor winds up but rather a direct and instantaneous full load on the driveline and axle, there will be shock loading applied to the gears. That indicates that a gear oil-type EP lubricant may be more appropriate.
Beyond that, EV batteries need to be cooled, and antifreeze or some chemical variant will be needed. Grease for the wheel bearings and constant velocity transaxles will probably be similar to current products. Again, there will likely be improvements once a better understanding of the electric motor’s impact on these assemblies is understood. The specialized greases and oils used in such things as door locks will probably be the same as current applications.
Steve Swedberg is an industry consultant with over 40 years experience in lubricants, most notably with Pennzoil and Chevron Oronite. He is a longtime member of the American Chemical Society, ASTM International and SAE International, where he was chairman of Technical Committee 1 on automotive engine oils. He can be reached at email@example.com.
For more information about the interface between lubricants and the EV market visit Electric Vehicles InSite.