The Ford Explorer is the most popular mid-size SUV in the USA, but it has the same problem as most other SUVs of its size – poor fuel economy. This Ford SUV is, therefore, also offered as a hybrid to improve matters somewhat, even though a combined EPA-estimated 27 MPG for the RWD models is still not all that good. Clearly, it’s a tall order to give a big, heavy, three-row SUV with lots of seats and cargo space good gas mileage, which is why the motoring industry has been shifting toward electric vehicles (EVs). But EVs are still cost more than gas cars due to their expensive batteries.
The good news is that an electric version of this Ford SUV is probably not that far off. Having already put the electric Mustang Mach-E crossover and F-150 Lightning truck on the market, it’s only a matter of time before the popular Explorer gets the EV treatment. The latest electric motors are over 95 percent efficient, charging infrastructure is improving, and electricity generation is getting greener by the day. Everything is in place, then, except batteries, which, although offering over 400 miles of range in the latest EVs, still make EVs more expensive than gas cars.
Aiming For Break-Even With Gas Cars
Depending on which of the latest studies you’ve read, EVs will achieve cost parity with gas cars anywhere between 2023 and 2027. Many industry pundits believe this will happen when batteries cost around $100 per kWh to produce and that this will be achievable with current lithium-ion (Li-Ion) battery technology. It is believed that Tesla might already be very close to that figure. In 2010, that number was around $1,100, so there have already been massive improvements. But does the future lie in Li-Ion batteries? Probably not.
The Main Battery Types
All the main battery types that have brought us to where we are today are still in use in many applications. Although there are countless combinations of battery chemistry, the most important types can be reduced to three:
- Lead-acid batteries. Hailing from the 19th century, these wet-cell or flooded batteries are filled with a mild sulfuric acid solution and their electrolyte levels must be kept topped up. They are cheap to make and proven, but discharging them below 50 percent shortens their lifespan – which is only around three years anyway. They are also very heavy, their discharging efficiency is below 80 percent, and their energy density is around 30 to 50 Wh/kg. The vast majority of normal under-hood batteries in gas and diesel vehicles today is still of this type and it’s still the most common battery used in normal cars. GM’s original EV-1 electric car of 1996 used lead-acid batteries, but their poor energy density and high weight make them unsuitable for modern EVs.
- Nickel-metal hydride batteries. Although nickel-metal hydride (Ni-Mh) batteries’ discharging efficiency is worse than that of lead-acid batteries at 70 percent or less, their far higher energy density that can reach 80 Wh/kg compensates for this. They also last far longer than lead-acid batteries – as long as a decade or 100,000 miles. The first generation of Toyota RAV4 EV used Ni-Mh batteries. They were also used in the 2001 Toyota Prius sold in the US, as well as the first Honda Insight.
- Lithium-ion batteries. Used in laptops and consumer electronics for decades, the mass adoption of Li-Ion batteries for EVs started with Tesla and today, essentially all EVs use this type of battery. It has a maximum energy density approaching 700 Wh/kg and a discharging efficiency of over 80 percent. They are around a third of the weight in comparison to a lead-acid battery, are around three times as powerful, and their cycle life is also around three times better. Various lithium chemistries are used, for example, lithium nickel cobalt aluminum oxide, lithium iron phosphate, lithium manganese oxide, and lithium nickel manganese cobalt. Fast charging and heat affect Li-Ion batteries’ lifespan more than actual use and age and with proper cooling, a modern EV’s Li-Ion battery should retain approximately 90 percent of its capacity after around six years. Some modern Li-Ion batteries are expected to last decades.