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Published on January 18th, 2016 | by Kyle Field

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Chevrolet Cracks Open the Bolt, Shares Drivetrain Details

January 18th, 2016 by  


cq5dam.web.1280.1280 (2)We were at the big reveal of the production version of the 2017 Chevy Bolt at the 2016 Consumer Electronics Show and spilled all the fun details coming out of the event, but Chevy didn’t give us all the goods in Vegas. In Detroit last week at the North America International Auto Show, Chevrolet cracked the new EV open for us to get a look at the drivetrain and battery system, including all sorts of technical details about the Bolt that many of us have been waiting for.

What’s evident from the newly released details is that the Bolt packs a punch, confirming the power we saw at CES when we hit the track with the Bolt. Under the hood, the 150 kilowatt motor blows off the line with the 360 Nm of torque punching passengers into their seats. At 1,750 kgs, the Bolt is no lightweight, but it is still expected to pull a sub-7.0 second 0-to-60 mph run, which is not bad for a small crossover with a 60 kWh battery pack in tow.

chevy_bolt_060

Chevy Bolt motor

About that battery pack, the 60 kWh lithium-ion battery pack contains:

  • 288 lithium-ion cells
    • 5 sections
    • 10 modules
    • 96 cell groups – 3 cells per group
  • 960 lbs. (435 kg) total weight

Preliminary design of the Chevy Bolt battery

GM is proud of the new pack as the manager of the Bolt EV battery pack engineering group, Gregory Smith related:

“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.”

The battery is in what now seems to be the standard skateboard layout, with the batteries arranged in a flat plank across the bottom of the car. This is ideal for handling, as it located the dense batteries and the large 435 kg battery array at the lowest point of the car, stabilizing the car around turns and curves in the road.

The cells in the Bolt have a new arrangement and a new chemistry vs other GM production vehicles, making use of a nickel-rich lithium-ion chemistry that offers improved thermal operating performance compared to other lithium-ion chemistries, resulting in a smaller cooling system.

cq5dam.web.1280.1280 (3)To keep the battery system charged up, a 7.2 kW onboard charger, which has the capability to charge up the pack 10% faster than most current EVs, which utilize a 6.6 kW charger. This is more than sufficient for the average commute but will quickly become a constraint for long-range driving. Utilizing the optional (what?!) SAE Combo DC Fast Charging adapter, a 30-minute charge will add up to 90 miles of range.

This is a clear indication that GM and Chevy don’t completely understand EVs. At this rate, the Bolt would need almost 2 hours to fully charge on a DC Fast Charger at a cost of around $30 bucks (based on $9.95/30 minute charge at NRG evGO DC Fast Charging stations). This might not seem like a major barrier, but having just driven 4,180 kilometers across the US in my Model S, this would be an insurmountable barrier for long-range travel. Yes, the range is an improvement, but those charging rates need some serious attention to fully crack the EV nut.

2017 Chevrolet Bolt EV

Getting into the Bolt, Chevrolet has integrated a new regenerative braking system that, similar to the BMW i3, allows for one-pedal driving. This not only boosts the range of the vehicle by translating the kinetic energy of the moving vehicle back into the battery, but also transforms the driving experience. One-pedal driving changes the feel of driving around town and on highways, offering a simplified driving experience that can all be managed with just the accelerator pedal.

The Bolt takes one-pedal driving to the next level with the capability to bring the vehicle to a complete stop without having to use the brake pedal in certain conditions. This brings up another question — will the use of strong regenerative braking trigger the brake lights? Should it? We will dig into this more in a future article, but until then, jump down to the comments to let us know what you think.

2017 Chevrolet Bolt EV

In addition to advanced one-pedal driving, the Bolt has a “Regen on Demand” paddle on the back of the steering wheel that gives the driver one more lever to pull to engage extreme regen. GM is careful to note that the new regen features do not obviate the need to use the brake pedal, but that it does have the ability to bring the car to a complete stop by itself.

 

GM has really built an exciting long-range EV with the Bolt, which looks to be a strong competitor in its class. Check out the preliminary specs from the press release below.

All images and videos by Chevrolet.

Overview

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

Battery System

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

Electric Drive

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

Charging Times

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

Performance

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

Chassis/Suspension

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

Brakes

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

Wheels/Tires

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

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

Capacities

Curb weight (lb / kg); 3580 lb / 1625kg based on target (w/o 2passengers)
Heating cooling (qt / L): Heating loop 1.8L
Battery pack cooling (qt / L): 6.9L (RESS cooling loop total coolant volume)
Power electronics cooling (qt / L): 3.9L (PE & DU cooling loop total coolant volume)
Drive unit fluid (qt / L): 2.9L

Note: Information shown is current at time of publication.

2017 Chevrolet Bolt Propulsion Overview

 
 





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I'm a tech geek passionately in search of actionable ways to reduce the negative impact my life has on the planet, save money and reduce stress. Live intentionally, make conscious decisions, love more, act responsibly, play. The more you know, the less you need. TSLA investor.



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