Updates to conventional cars come in a predictable pattern.
Once a new model is launched, it gets only minor tweaks to features, prices, and paint colors for two or three years.
Then in the third or fourth year, it gets what the industry calls a "mid-cycle refresh": some updated sheetmetal, perhaps a redesigned dashboard, and other more visible changes.
That version lasts for another two or three years, then an entirely new generation is launched. Rinse and repeat, for years and decades.
But the pace of improvement in lithium-ion battery cells—roughly 7 percent a year—makes that cycle somewhat irrelevant, as makers are learning.
Which brings us to the 2018 Kia Soul EV, which has a higher-capacity battery (30 kilowatt-hours rather than 27 kwh) and hence a longer EPA-rated electric range: 111 miles, up from 93 miles.
This is actually the fourth model year for the Soul EV, presently the only battery-electric model that Kia sells.
The Soul EV is a heavily converted model of Kia's popular compact tall wagon, the highest-selling vehicle in the brand's U.S. lineup.
It doesn't sell in huge numbers—1,000 to 2,000 a year, apparently—and it's only offered in a limited handful of states.
READ THIS: 2015 Kia Soul EV: First Drive Of Newest Electric Car (Nov 2014)
Still, the square, upright vehicle offers more interior volume for people and their goods than do sleeker, lower five-door hatchbacks with the same footprint.
That's endeared the Soul EV to its drivers, who also say they can often exceed the EPA-rated range, at least in temperature weather.
We found that to be true in our 2014 drive of an earlier Soul EV, which gave us more than 100 miles in urban and suburban driving (on a rated range of 93 miles) and about which we concluded, "This is a 100-mile electric car."
Battery update aside, the 2018 Kia Soul EV has few other changes to differentiate it visually or functionally from the one on sale since late 2014.
Its motor remains rated at 81 kilowatts (109 horsepower) and 210 pound-feet of torque, and includes not only a 6.6-kw onboard charger but also standard CHAdeMO 50-kw fast charging.
The electric Soul is again offered in three trim levels starting with the EV-e2 ($33,145 including delivery) and topping out at the EV+ ($36,845 plus options).
CHECK OUT: Kia Soul EV Sales Expand Again, To Four Northeast States (Nov 2015)
It joins a growing roster of plug-in cars, both battery-electric and plug-in hybrid, that have received battery updates on a similar or even quicker schedule than the standard mid-cycle refresh.
The first-generation Chevrolet Volt plug-in hybrid was launched in 2011, and received battery upgrades in 2013 and 2015. The second-generation Volt in 2016 got another upgrade.
Likewise, the 2018 Volvo XC90 T8 plug-in hybrid luxury SUV got a higher-capacity battery in only its third year on the market.