Simanaitis Says

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EV GLOSSARY

THIS IS a bit longer than the usual mini-essay, but for completeness it’ll be a single item. I’ll not fancy it up with photos or charts; it’s a glossary, pure and not so simple.

Battery cell, module, pack – Three distinct levels of battery technology are the basic battery cells, their assemblage into a module and the modules’ packaging into a final automotive battery pack. This obfuscates discussions of costs. Some cite cell cost; others, modules; still others, battery packs.

Battery cost – Proponents say battery costs are perhaps $600/kWh, with goals of $200/kWh or less. Others say they’re currently $700-$1000/kWh. It’s not always made clear whether it’s cell, module or pack. Regardless, its battery pack is the most expensive component of an EV.

Battery size, energy – The energy contained in a battery pack is measured in kWh (kilowatt-hours; not kW/h). Other things equal, energy dictates range—and comes at a commensurate cost.

Battery energy, cost, EV range –The Tesla Model S BEV provides an excellent example. Three versions have different battery sizes offering different range expectations:

40 kWh      est. 141 miles               $49,900

60 kWh      est. 203 miles               $59,900

85 kWh      EPA 265 miles             $69,900

Battery longevity – HEV nickel/metal-hydride battery packs last the life of the vehicle; a 10-year data base has corroborated this. Lithium-ion battery packs generally have 8-year warranties. Their PHEV and BEV applications are too recent to accumulate much data.

Battery type – Most advanced batteries are of lithium-ion technology; variations exist in electrode material choice. The more mature nickel/metal hydride technology continues in some applications.

BEV –A Battery Electric Vehicle stores all of its on-board energy in a battery pack.

Charge connectors, J1772, CHAdeMO, SAE Combo – Recharging at 120- or 240-volts alternating current uses a plug standardized by SAE J1772. Quick charging, however, is not uniform. The Nissan Leaf and Mitsubishi i use a Japanese standard CHAdeMO plug. A more recent expansion of J1772 offers the SAE Combo, accepted by many U.S. and European carmakers. Tesla has one incompatible with the others, its Supercharger with substantially higher charge rate.    

Charge, home, office, or by opportunity – Automakers prefer the concept of home or office charging, at a known location for a known length of time. Opportunity charging at a mall or the like is seen as less useful: Can it be assured the opportunity charger will be available when needed?

Charge rate – The rate, measured in kW, at which a BEV or PHEV can accept recharging from its plug-in source. All else equal, an on-board charger of 6.6 kW will accept a given charge in approximately half the time of a 3.3-kW counterpart. Tesla opts for 20-kW charging at 100 amps.

Electric motor – To avoid ambiguity, it’s helpful to differentiate between an electric motor and an internal-combustion engine. An electric motor offers high efficiency and maximal torque from zero rpm.  Its power is measured in kW; 1 kW = 1.34 hp, this abbreviation used rather than bhp.

Emergency charging – Organizations such as AAA offer contracted on-road minimal recharging, enough to get home, not to extend a journey.

EPA range assessment –Monroney stickers show both mpg-equivalent (mpge) data as well as information on estimated range. The latter appears to mirror reality better than mpge.

EV – To some, the term Electric Vehicle is synonymous with BEV. To others, an EV is any that derives at least some propulsion from an electric motor: HEVs, PHEVs, BEVs and FCEVs are EVs.

FCEV – A Fuel Cell Electric Vehicle produces its own on-board electricity by means of a fuel cell.

Fuel cell – A fuel cell transforms hydrogen and oxygen into electricity, trace water and heat.

Government EV incentives – Federal, state and local EV incentives generally depend on the battery’s energy. BEVs, PHEVs and some HEVs qualify for various federal tax credits. These are not rebates subtracted from initial cost; rather, they’re potential credits on income tax.

HEV – A Hybrid Electric Vehicle derives propulsion from both an engine (typically gasoline-fueled) and an electric motor supported by an on-board battery. Engine/motor interactions—not a plug—charge its battery. Example: a conventional (i.e. non-Plug-in) Toyota Prius.

HEV vs PHEV vs BEV – The more pure electric travel, the larger battery required:

Toyota Prius HEV                 1 mile       1.3 kWh

Toyota Prius PHEV              11 miles    4.4 kWh

Ford C-Max Energi PHEV   20 miles     7.5 kWh

Chevrolet Volt PHEV           35 miles   16.5 kWh

Nissan Leaf BEV                   73 miles   24.0 kWh

Home voltage, amperage – Home recharging might be at typical alternating-current conditions of 110 volts/20 amps. Newer homes may offer 220 volts/40 amps. Either may require a dedicated line. Cost of a unit is approximately $2000 and varies widely with home age and wiring.

PHEV – A Plug-in HEV derives part of its electrical energy from plugging into the utility infrastructure. Some PHEVs (Toyota Prius) use both the engine and electric motor interactively for propulsion. Others (Chevrolet Volt) use the engine primarily to drive an electric generator.

Precious metals – Elements such as platinum are used as catalysts promoting chemical activities in automotive catalytic converters and fuel cells.

Rare earth metals – Elements such as lanthanum and neodymium are used in battery electrodes and electric-motor magnets. China is a predominant, though not the only, source.

Regenerative braking – Converts the kinetic energy of braking into electrical energy.

Quick charging – Direct-current 440-volt high-amp charging refreshes 80 percent of a battery’s capacity in 30 minutes. Units are an order of magnitude more costly than 120- or 240-volt chargers. Quick-charge connectors are not standardized at this time. Frequent use degrades battery longevity.

Weather and climate – Extreme heat or cold degrades battery performance. Air-conditioning and, particularly, heating an EV can cut range by as much as 30-40 percent. Pre-heating or pre-cooling of a BEV or PHEV while still plugged in can lessen this.

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This entry was posted on December 4, 2012 by in Driving it Today, Sci-Tech and tagged , , , , , .
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