http://insideevs.com/gm-exec-chevrolet-bolt-exceeding-200-mile-range-estimates-in-internal-testing/ GM Exec: Chevrolet Bolt Exceeding 200-Mile Range Estimates In Internal Testing [20160407] Eric Loveday
[images http://insideevs.com/wp-content/uploads/2016/03/Chevrolet-Bolt-EV-NY-Auto-Show-2016-via-Tom-M-2.jpg Chevrolet Bolt http://insideevs.com/wp-content/uploads/2016/03/chevrolet-bolt-ev-interior-dash-2-NYAIS16-via-David-Ringgold.jpg http://insideevs.com/wp-content/uploads/2016/01/Chevrolet-Bolt-EV-battery-60-kWH.jpg Chevrolet Bolt EV Battery – 60 kWH ] According to General Motors’ general director-electrification, Tim Grewe, prototypes of the Chevrolet Bolt are exceeding 200 miles of electric range in internal testing. Crewe spoke to media recently at GM’s Alternative Energy Center and confidently stated that the production Bolt will exceed the 200 miles of range that Chevrolet had originally announced. EPA testing for the Bolt has not been completed, but GM is confident in the results from internal tests. Additionally, Greg Smith, General Motors’ engineering group manager-global EV battery packs, says that compared to the Chevy Spark EV, the Bolt’s battery has twice the mass and triple the energy. Smith adds that the Bolt’s battery actually increases the car’s chassis torsional stiffness by 28% due to it being an integrated part of the Bolt’s floorpan. Grewe adds: “A high-mass, large battery turned into a benefit that is a big factor in making the car fun to drive.” [© 2016 Inside EVs] http://m.wardsauto.com/engines/gm-ev-bolting-past-200-mile-range GM EV Bolting Past 200-Mile Range Apr 06, 2016 Bob Gritzinger [images http://m.wardsauto.com/site-files/wardsauto.com/files/imagecache/medium_img/uploads/2016/04/bolt-engineers-resized.jpg GM EV engineers (from left) Greg Smith, engineering group manager-electrification; Tim Grewe, general director-electrification; and Stephen Poulos, global chief engineer-electrification, with Bolt EV battery pack http://m.wardsauto.com/site-files/wardsauto.com/files/uploads/2016/04/Bolt%20battery%20resized.jpg Battery packs (from left): First-gen Volt, second-gen Volt, Spark EV and Bolt EV http://m.wardsauto.com/site-files/wardsauto.com/files/uploads/2016/04/Bolt%20motor%20resized.jpg (Bolt’s electric-drive unit) ] GM engineers say the Chevrolet Bolt EV will exceed the company’s original range estimate of 200 miles. The $35,000 electric CUV goes on sale later this year. WARREN, MI – The Chevrolet Bolt, General Motors’ small electric CUV due late this year, will exceed the 200-mile (322-km) range the automaker originally suggested as the car’s maximum, engineers reveal during a media briefing at GM’s Alternative Energy Center here. Tim Grewe, general director-electrification, says prototypes have pushed past that number and he expresses confidence many buyers of the $35,000 EV will exceed the 200-mile range. Official numbers aren’t expected for several months, but hitting that distance is key because GM says its market research shows 70% of buyers would consider owning an EV as their primary vehicle with that capability. Beating 200 miles also is important in light of competitor Tesla’s announcement last week its Model 3, due in late 2017, will travel 215 miles (346 km) on a charge. More than 250,000 potential buyers have placed deposits for the car, which also has an estimated starting price of $35,000. The second-generation Nissan Leaf due in 2017 also is expected to hit a similar range and price point. Range and pricing aside, GM engineers say the Bolt’s clean-sheet design represents a revolutionary leap in electrification technology, from its optimized battery pack to its compact 200-hp electric drive motor. Compared to the Spark EV, for instance, the Bolt’s 961-lb. (436-kg) lithium-ion battery pack has twice the mass but produces triple the energy at 60 kWh, says Greg Smith, engineering group manager-global EV battery packs. The nickel-enriched cells provide a higher tolerance for heat while offering increased capability, he says. At the same time, the Bolt’s battery pack increases chassis torsional stiffness 28% due to its rigid construction that includes five integrated crossmembers as part of what essentially makes the battery a structural component of the floor pan. “A high-mass, large battery turned into a benefit that is a big factor in making the car fun to drive,” Grewe says. The entire battery system and structure, including 96 individually serviceable cells packaged into five temperature-controlled modules, is built by LG in Korea and shipped to GM’s Orion Township, MI, plant for installation into the vehicle. Meanwhile, the Bolt’s electric-drive unit at 168 lbs. (76 kg) is just 18 lbs. (8 kg) heavier than the unit in the Spark EV, but offers higher power and torque densities and operates at nearly double the maximum speed at 8,810 rpm. GM says peak efficiency is about 97%. The motor also is built by LG in Korea. GM says the combination of optimal battery and motor sizing gives the 3,580-lb. (1,624-kg) Bolt a sub-7.0-second 0-60 mph (97 km/h) time, along with a quick launch time. Recharge time is 30 minutes to accumulate about 90 miles (145 km) of stored power on a DC fast-charging system, while a full charge takes nine hours on a 240V charger. GM says it doesn’t expect the Bolt to compete with the Volt for customers and unlike Tesla, the company isn’t taking deposits for the car and won’t reveal how much interest it has drawn from potential buyers. [© 2016 Penton] http://www.hybridcars.com/gm-engineers-discuss-the-2017-chevy-bolts-powertrain/ GM Engineers Discuss the 2017 Chevy Bolt’s Powertrain April 6, 2016 Jeff Cobb [images / Jeffrey Sauger/GM http://www.hybridcars.com/wp-content/uploads/2016/02/2017-chevrolet-bolt1-668x409-668x409.jpg (bolt) http://www.hybridcars.com/wp-content/uploads/2016/04/2016-0405-jms-GM-Bolt-Battery-011-e1459989151529.jpg Greg Smith, Engineering Group Manager, Electrification, left, Tim Grewe, General Director, Electrification, center, and Stephen Poulos, Global Chief Engineer, Electrification, right, pose with a Chevrolet Bolt EV battery pack and drive unit in General Motors Global Battery Systems Laboratory at the GM Technical Center in Warren, Michigan, Tuesday, April 5, 2016 http://www.hybridcars.com/wp-content/uploads/2016/04/Psumary.jpg (performance sumary) http://www.hybridcars.com/wp-content/uploads/2016/04/propulsion.jpg (propulsion) http://www.hybridcars.com/wp-content/uploads/2016/04/2016-0405-jms-GM-Bolt-Battery-004.jpg Chevrolet Bolt EV drive unit http://www.hybridcars.com/wp-content/uploads/2016/04/driveunit.jpg driveunit http://www.hybridcars.com/wp-content/uploads/2016/04/2016-0405-jms-GM-Bolt-Battery-001-e1459993173725.jpg Volumetrically, the Bolt battery is nearly double the size (2.05 times the size) as the Spark EV’s but has more than triple the capacity (60 kilowatt-hours versus 18.4 kwh for the Spark). This is because the pack energy density is 60-percent greater. Warranty: 8 years or 100,000 miles. Actually, said GM, it’s designed to last for the life of the car – though they did not specify the precise mileage defining a car’s lifespan. http://www.hybridcars.com/wp-content/uploads/2016/04/battery-topology.jpg battery topology http://www.hybridcars.com/wp-content/uploads/2016/04/Bolt_EV-e1459989869499.jpg (Sonic/bolt chassis under pinnings) ] To date Chevrolet has accepted zero pre-orders for its 2017 Bolt EV, it makes no attempt to one-up fashionable German sedans, but it does have a few things going for it. One is the purpose-built electric car will be for sale and in production at the end of this year – a year-and-a-half or more ahead of Tesla’s Model 3 – and will thus be the first 200-plus-mile EV priced from the mid 30s. While the public and press are still dazzled after last Thursday’s Tesla reveal and nearly 300,000 paid reservations that piled in within a couple days after the event, yesterday General Motors in more quiet fashion spoke of the merits of its EV’s powertrain. The occasion was a tech talk led by the automaker’s chief engineers at its Global Battery Systems Laboratory in the GM Technical Center in Warren, Michigan. Although a couple journalists tried to lure them into comparing the Chevy compact crossover to the Model 3, they deftly ducked those and stayed on point. Be that as it may be, it is long a matter of record that GM did build the Bolt at least in partial response to Tesla’s proposed $35,000 EV now known to have at least 215 miles range. Headlines since last year also have included the term “Tesla killer” describing the Bolt to provoke reader clicks online, but GM this week was not going there, and let the facts speak for themselves. Legacy GM said independent market research had shown that 70 percent of would-be EV buyers indicated they would be sufficiently content with 200-miles range to the point that they could live with it in their one and only car ... The mission to build a 200-mile EV was spilled in 2013 by then-CEO Dan Akerson. At the time the news received an approving tweet from Elon Musk. GM has since said it has built on lessons learned with the Chevy Volt, Spark EV and other experience garnered along the way. The track record with the Volt’s powertrain has been especially stellar as noted last year by Larry Nitz, General Motors’ vice president of electrification. “We’ve seen what I would call pharmaceutical levels of quality in cell production,” he said during a Volt ride and drive event. “Of the more than 20 million cells that have been produced for the first generation Chevy Volt, we’ve seen less than two problems per million cells produced.” Volt batteries and drive units have been reported as durable. The highest-mileage Volt known now with over 300,000 total road miles and 105,000 EV miles and belonging to Erick Belmer of Ohio holds about as much energy in its T-shaped battery as it did when new. As for the Spark EV, it is sold just in California, Oregon and Maryland but GM shoehorned an over-powered electric motor in it, and it too was a source of data and some hardware also for GM to build the Bolt. Its 0-60 mph time may be in the six-second range, though GM is only saying below seven seconds at this point. Zero to 30 comes in a right-quick 2.9 seconds from the front-wheel driver. Its range is to be more than 200 miles from its nominally 60-kilowatt-hour in-floor battery assembly. Propelling the EV is a single-motor drive unit developed in-house by GM. Motor The Spark EV uses an existing GM motor design which has a lower maximum speed of 4,500 rpm but higher torque output of 327 pounds-feet (444 Nm). Horsepower for the Spark EV’s motor is 105 kilowatts (140 horsepower) and the new Bolt EV has 150 kilowatts (200 horsepower). Stephen Poulos, global chief engineer, Chevrolet Bolt EV propulsion system, said the Bolt’s new motor design has a higher max speed of 8,810 rpm, but lower torque at the motor of 273 pounds-feet (370 Nm). It also has a higher fixed gear ratio of 7.05 versus 3.87 which allows higher final torque at the axle – approximately 1,844 pounds-feet (2,500 Nm) versus 1,261 pounds-feet (1,710 Nm). The Bolt’s new motor uses bar-wound copper with “lots of copper fill” and end turns, and “takes a lot of experience and skill” to produce, but the automaker has become “pretty good at it” he said with deliberate understatement. That said, the design is not otherwise exotic or unusual but the motor did receive a lot of computer optimization. This followed proprietary GM software to yield weight efficiency versus motor cost across multiple typical motor operation rpm and torque load regions. The Bolt’s motor reaches a peak efficiency of 97 percent under some conditions – very high. Battery `The Bolt’s large in-floor battery uses LG Chem cells that have evolved beyond what the Volt gets with a chemistry providing a higher balance of energy than power in the power-to-energy ratio, and best suited for EVs, says GM. Warranty: 8 years or 100,000 miles. Actually, said GM, it's designed to last for the life of the car – though they did not specify the precise mileage defining a car's lifespan. Almost all of the energy is used in a full discharge cycle, and very little is left as a “buffer” as in the case of the Volt extended-range EV. GM’s Greg Smith, engineering group manager, global EV battery packs avoided calling the battery “better” but said it is bleeding edge, he is “proud” of the total result, and it’s the best they have for the application. The LG Chem cells are of NMC chemistry with extra nickel for improved heat tolerance, said Smith. Further, the pack will be allowed to run a bit warmer than in the Volt. Temperatures in the pack change slowly, he said, due to the entire assembly’s 960 pound mass. Speaking also of the assembly, it is an integral member of the chassis. Smith said the tray – or bottom of the battery pack – is “extraordinarily stiff” and adds a substantial 28 percent to the body’s torsional rigidity. Overall, the pack is “ridiculously rigid” and is made up of multiple layers. Any crash forces during an accident shouldn’t get into the pack due to carefully positioned structural cross bars. More to Come Obviously the Bolt is more than an optimized and well-sorted powertrain. From the outset the mission was to make a “super functional” vehicle, said Tim Grewe, general director, electrification. The Bolt is also a marvel of space utilization with flat floor, good ingress and egress, and room for five people plus cargo. Features include a 10.2 inch touchscreen with Chevy MyLink, gads of safety tech, and it represents an integrated holistic approach as General Motors’ first purpose-built EV since the EV1. Beyond “regen on demand” and a paddle to control this, GM built in “one pedal drive” where the regen can bring the Bolt to a stop with no creep, so the driver may use just the accelerator in this mode. Total range should be within the ballpark of the Model 3, but GM’s Kevin Kelly said the EPA certifications are a “couple months” away and for now it’s only saying over 200 miles. So stay tuned for that and other news GM will release as Chevrolet prepares to begin selling the 2017 Bolt EV through its nationwide dealer network late this year. 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