Drive Unit and Battery at the Heart of Chevrolet Bolt EV Engineers focus on careful balance of range and performance

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DETROIT – The 2017 Chevrolet Bolt EV does more than set a new benchmark for affordable, long-range EV driving. It also raises the bar when it comes to driving performance.

Engineers developed the Bolt EV’s propulsion system to offer more than an estimated 200 miles (based on GM estimates) and a delightful driving experience that’s more akin to a compact sports sedan than a small utilitarian crossover.

“Being the leader in range and affordability means nothing if the car isn’t going to excite you each time you get behind the wheel,” said Josh Tavel, Chevrolet Bolt EV chief engineer. “That’s why the team was tasked with delivering a propulsion system that would also make the Bolt EV an electric vehicle that owners would love to drive.”

Single Motor Drive Unit

Like most EVs on the road, the Bolt EV’s drive system uses a single high capacity electric motor to propel the car. But it’s the smooth, powerful and quiet motor design, gear configuration and shift-by-wire system that separates it from the pack.

The engineering team designed the Bolt EV’s electric motor with an offset gear and shaft configuration tailored to meet efficiency and performance targets – most notably more than an estimated 200 miles of range. The motor is capable of producing up to 266 lb.-ft. (360 Nm) of torque and 200 hp (150 kW) of motoring power. Combined with a 7.05:1 final drive ratio, it helps propel the Bolt EV from 0-60 mph in less than seven seconds.

Power delivery is controlled by Chevrolet’s first Electronic Precision Shift system. This shift and park-by-wire system sends electronic signals to the Bolt EV’s drive unit to manage precise feel and delivery of power and torque, based on drive mode selection and accelerator inputs. A by-wire shifter requires less packaging space than a traditional mechanical shifter, resulting in more interior space and improved interior layout.

60 kWh Battery System

Having more than 1.3 billion miles of EV experience from the Chevrolet Volt helped Bolt EV battery engineers and strategic partner LG Electronics to develop an all-new cell and battery pack to offer more than an estimated 200 miles of range.

Battery system preliminary specifications include:

60 kWh lithium-ion battery pack.

288 lithium ion cells Five sections 10 modules 96 cell groups – three cells per group

960 lbs. (435 kg) total weight

“You usually have a battery cell that delivers either the desired levels of energy or power, but not traditionally both. With this cell design and chemistry we were able to deliver a battery system with 160 kilowatts of peak power and 60 kilowatts hours of energy,” said Gregory Smith, Bolt EV battery pack engineering group manager.

The battery uses active thermal conditioning, similar to the Chevrolet Volt, to keep the battery operating at its optimum temperature, which results in solid battery life performance. The Bolt EV battery will be covered by an 8-year/ 100,000 mile (whichever comes first) limited warranty.

Inside the battery pack – which spans the entire floor, from the front foot well to back of the rear seat – is a new cell design and chemistry. The nickel-rich lithium-ion chemistry provides improved thermal operating performance over other chemistries, which requires a smaller active cooling system for more efficient packaging. The chemistry allows the Bolt EV to maintain peak performance in varying climates and driver demands.

The cells are arranged in a “landscape” format and each measures in at only 3.9 ins. (100 mms) high and 13.1 ins. (338 mms) wide providing improved packaging underfloor. The lower profile cell design enabled the vehicle structure team to maximize interior space.

The battery system is mated to a standard equipment 7.2 kW onboard charger for regular overnight charging from a 240-V wall box. A typical commute of 50 miles can be recharged in less than two hours. Bolt EV also features an optional DC Fast Charging system using the industry standard SAE Combo connector. Using DC Fast Charging, the Bolt EV battery can be charged up to 90 miles of range in 30 minutes. Outside temperatures may affect charging times.

Regen System Provides One-Pedal Driving

Regenerative braking has become more than just a tool to boost range, it’s also transformed into a feature that can provide an improved EV driving experience. The Bolt EV features a new regenerative braking system that has the ability to provide one pedal driving.

“Interviews with EV enthusiasts indicated their desire for one pedal driving capability on the Bolt EV. One pedal operation boosts the thrill and uniqueness of EV driving,” Tavel said.

Through a combination of increased regenerative deceleration and software controls, one pedal driving enables the vehicle to slow down and come to a complete stop without using the brake pedal in certain driving conditions.

When operating the Bolt EV in “Low” mode, or by holding the Regen on Demand paddle located on the back of the steering wheel, the driver can bring the vehicle to a complete stop under most circumstances by simply lifting their foot off the accelerator, although the system does not relieve the need to use the brake pedal altogether.

Operating the Bolt EV in “Drive” mode and not pulling the paddle while decelerating delivers a driving experience where usage of the brake pedal is required to stop.

Founded in 1911 in Detroit, Chevrolet is now one of the world's largest car brands, doing business in more than 115 countries and selling around 4.8 million cars and trucks a year. Chevrolet provides customers with fuel-efficient vehicles that feature engaging performance, design that makes the heart beat, passive & active safety features and easy-to-use technology, all at a value. More information on Chevrolet models can be found at www.chevrolet.com.

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Model: Chevrolet Bolt EV Body style / driveline: front-wheel-drive, five-passenger, five-door all-electric CUV Construction: Steel and Aluminum EPA vehicle class: Small Wagon (EPA does not have a cross-over category) Key competitors: Nissan Leaf, BMW i3, Ford Focus Electric, Kia Soul EV, VW eGolf Mercedes-Benz B-Class Electric Manufacturing location: Orion Township, Mich. Battery manufacturing location: Incheon, South Korea Motor and drive unit manufacturing location: Incheon, South Korea

Type: rechargeable energy storage system comprising multiple linked modules Volume/case: 285L Mass (lb / kg): 960 lb./435 kg Battery chemistry: lithium-ion Thermal system: liquid active thermal control Cells: 288 Electric driving range: More than 200 miles (GM estimate pending final tests) Energy: 60 kWh Warranty: eight years / 100,000 miles

Type: Single motor and gearset Motor: permanent magnetic drive motor Power: 200 hp/150 kW Torque: (lb-ft / Nm): 266 lb.ft./360 Nm Final drive ratio (:1): 7.05:1

120 V: Available with standard cordset 240 V: 50 miles of range in less than 2 hrs. SAE Combo DC Fast Charge: 90 miles in 30 minutes

Top speed (mph): 91 mph / 145 kph * 0-30 mph: 2.9s (75% SoC) * 0-60 mph: Under 7 seconds

Front: Independent MacPherson strut-type front suspension with side load compensating and finely tuned springs, direct-acting solid stabilizer bar system and ride & handling oriented LCA bushings. Rear: Compound crank (torsion beam) type rear suspension with the closed section V-shaped profile axle; specifically tuned coil springs, performance balanced shock absorber, angled A-bushing supporting understeer tendency on cornering maneuver and kinematically optimized torsion beam providing stable and best ride & handling performance. Chassis control: Four-channel ABS; Traction control system; StabiliTrak; Drag control Steering type: column-mounted electric power steering Steering wheel turns, lock-to-lock: 2.91 revolution * Turning radius, curb-to-curb ( ft. / m): 10.8m * Steering ratio: 16.8 :1

Type: power four-wheel disc with ABS; electro-hydraulic; partially regenerative; dynamic rear brake proportioning Brake rotor diameter front (mm / in): 276mm Brake rotor diameter rear (mm / in): 264mm Total swept area (cu cm): Front : 1398.9 Rear : 1131.4

Wheel size and type: 17in x 6.5J offset 44, cast aluminum Tires: Michelin Energy Saver A/S 215/50R17 all-season

Back to top Dimensions Exterior Wheelbase (in / mm): 102.4 / 2600 Overall length (in / mm): 164.0 / 4166 Overall width (in / mm): 69.5 / 1765(W103) Track width front (in / mm): 1500.92 mm Track width rear (in / mm): 1501.05 mm Height (in / mm): 62.8 / 1594(H100) Front overhang (in / mm): 32.9 / 836 Rear overhang (in / mm): 28.7 / 730 Interior

Seating capacity (front / rear): 2 / 3 Headroom (in. / mm): 39.7 / 1009 1st row

37.9 / 962 2nd row Shoulder room (in / mm): 54.6 / 1387 1st row

52.8 / 1340 2nd row Hip room (in / mm): 51.6 / 1310 1st row

50.8 / 290 2nd row Legroom (in / mm): 41.6 / 1056 1st row

36.5 / 927 2nd row Cargo volume (cu ft / L): 16.9 cu-ft / 478 L

(V10, Wagon CVI – Max behind rear seat) Passenger volume (cu ft / L): PV1 52.2 cu-ft / 1478 L 1st row

PV2 42.2 cu-ft / 1195 L 2nd row