BMW batteries for electric Commodore
BY MARTON PETTENDY | 31st Oct 2011
Assembly of the unique battery pack, designed specifically to fit into the engine bay and transmission tunnel of a standard Commodore sedan, is now taking place at EV Engineering’s Melbourne facility.
Validation testing of the completed vehicle is due to be finalised by the end of February.
Speaking at an Australian electric vehicles conference in Brisbane last week, chief engineer Tim Olding said EV Engineering remained on target to build seven proof-of-concept Commodore EVs by mid-2012, when field demonstrations and trials start.
“By the end of this year we’ll have two running electric cars, which we’ll do all our engineering testing, development and validation on,” said Mr Olding, a 19-year Holden veteran.
“By the 25th of June next year we aim to have our seven demonstration cars complete, so it’s a very compressed program.” Funded in part by a $3.5 million grant from the federal government’s now defunct Green Car Innovation Fund, EV Engineering’s $26 million project to produce an Australian-built rear-drive large electric car based on Australia’s top-selling model was announced in February.
“We dodged a bullet in terms of the cutting-off of the fund by a few days, so that was quite a relief,” said Mr Olding.
“We were very fortunate to get that money and it’s being put to good use.” Consortium members include automotive component suppliers Futuris, Air International, Bosch and Continental, EV charging network company Better Place and, most recently, Australia’s largest provider of fleet vehicles, GE, the parent company of Custom Fleet.
With support from GM Holden and the CSIRO, they aim to demonstrate the viability of a full-size factory-built sedan that consumes no petrol, delivers at least 160km of all-electric motoring and comes with a switchable battery to make it ‘range unlimited’.
“The opportunity only exists for a certain amount of time, so we really have to work fast and hard to take advantage of that opportunity,” said Mr Olding.
EV Engineering has forecast that, excluding its battery, the electric Commodore would be no more expensive than the model on which it is based.
“These (seven) cars cost a lot more than you’d want to pay because they’re prototype vehicles using low-volume manufacturing methods with unique componentry.
“But if you look around the industry at what a powertrain of that size would cost to manufacture, there is absolutely no reason that this car – without battery – could not be made for the same price as a V6-powered equivalent car.
“You then add the battery cost on top of that – and you’ve all seen the cost curves of the batteries, so over time that’s certainly going to become less of an issue.
“But even today if you pick up the Better Place model where the person or company buys the car – Better Place owns the battery – then your up-front costs are effectively the same as buying a traditional vehicle.” Mr Olding said that more than 500kg had been removed from the V6-powered Commodore donor vehicle at the start of the project, meaning the electric version would not be significantly heavier than the donor car.
“These (Commodores) have high-performance powertrains and they’re actually quite heavy, so the offset for electric (power) is not so severe.
“More than 500kg of components was removed from the car, so that gives you a nice amount of mass to work with to put back the battery plus the electric powertrain, and not be too much heavier than the original vehicle.” In an almost identical layout to that of Tesla’s all-new Model S electric sedan, the battery pack replaces the engine and transmission at the front and underneath the Commodore.
Its preassembled power control module resides in the space vacated by the fuel tank and an electric motor is positioned between the rear wheels instead of a differential.
GM Holden, which will introduce its first electrified vehicle in Australia next year in the form of GM’s Volt plug-in hybrid, has not provided financial backing for the project, but will supply the initial vehicles, data for those vehicles and the use of its proving ground at Lang Lang.
Mr Olding said EV Engineering’s decision to use the Commodore platform allows the finished product to retain all of the car’s rear-drive handling attributes and represents the most cost-effective way an electric vehicle could be produced in Australia.
“If we can actually make this work it’s probably the most cost-effective way for electric cars to be made in Australia, and probably the most likely way it will happen,” he said.
“What we’re producing is a concept that could be considered for future mass production. We’re doing that by building a fleet of seven cars over the next eight months.
“We wanted to focus on a car that fleets and people traditionally wanted to buy and the Commodore has been a very strong seller in Australia for a very long time and has a very strong uptake from the corporate vehicle fleet sector, and then a very good resell into the family driver market after that.
“We wanted to include battery swap for unlimited range because that greatly enhances the utility of the products and takes away some of these range-anxiety issues.
“Very importantly, this model includes a minimum of engineering and manufacturing investment.
“The Australian car industry is relatively small from a global perspective, so to actually design and build a ground-up EV in Australia would be a very large investment, for potentially a modest market size. So it would be very hard to make those economics work.
“But if you can flex an EV off an existing architecture you save a great deal of money. The design of the vehicle body – the steel structure that makes up the car – makes up a very large proportion of the investment.
“We also want to make it run down an existing production line alongside ICE (internal combustion engine) models.
“Once again that gives you the flexibility, so as the markets move and uptake increases, you can change the ratio of petrol-driven cars to electrically driven cars in a seamless way, so you’re not locked into fixed volumes of each variant.
“When you put all those things together and you look at the architecture … there’s a pretty strong case for using a rear-wheel drive architecture to do all that.
“If you look at a rear-wheel drive car, you’ve got a very large space where you can put the battery and powertrain without touching any of the sheetmetal. It also allows us to keep the battery and other components well within the protected zone within the vehicle from a crash point of view.
“You can design it in a way that vehicle assembly is consistent with traditional vehicle manufacturing methods, and quite easily have ICE variants of the same car going down the same production line.
“So there’s no major body engineering program required and the other nice thing is that it retains a lot of the DNA of the parent vehicle.
“The ride/handling attributes of a rear-wheel drive vehicle are kind of considered to be superior to a front-wheel drive car and you retain all of those attributes. It’s got essentially the same ride/handling performance as the base vehicle.
“That’s the vision we came up with when we first started looking at all the options and it very quickly became apparent that rear-wheel drive – it could be Falcon or Holden – has those attributes, which make it quite an attractive package.” All of the Commodore EV’s suspension components are carried over from the showroom model, but the rear suspension is attached to the electric motor and gearbox in a new steel frame that is fitted to the vehicle in a single module.
“It’s a very simple assembly process – all nice and modular – and it’s easy to imagine how all this would work on a production line.” However, Mr Olding said the inability to source a switchable battery pack to fit the Commodore’s unique platform and the requirement for the Commodore’s sheetmetal to remain unchanged forced EV Engineering to assemble its own battery pack from Li-Ion cells sourced from Korean-based battery supplier SB LiMotive – a joint-venture between Samsung and consortium member Bosch.
“The downside is the battery has to fit the car, so its actual shape is quite odd,” he said. “But the cells are nice building blocks – you can actually configure them to take advantage of the volume you have.
“Because of the scale of the project and the nature of the battery we’re looking at, it wasn’t possible for us just to go to a battery supplier and say ‘build us a battery’. They weren’t too keen on that idea, but we were able to secure very good cells from which we could build our own battery pack.
“They are the same cells that go into the BMW i3 and i8 products, so it’s a nice high-quality product and that’s the advantage of having partners like Bosch – they can give you access to the right technologies.” The Commodore EV prototypes will be powered by 210 40-amp-hour cells, each of which are positioned on a water-cooled plate to extract heat, positioned four storeys high at the front and one high at the rear, and fitted with a quick-coupling device to allow fast replacement.
Mr Olding said the Commodore EV project, which was driven by Better Place to advance the cause of electric vehicle design and manufacturing in Australia, played to the strengths of the local industry.
“The Australian automotive engineering industry can do a lot with a small amount of resources in a limited timeframe.
“One thing we do well is make multiple versions of products from a common architecture on a single assembly line with a combination of powertrains. At one stage I think Holden was manufacturing up to 30 different variants on the same production line at a given time, all on a common body architecture.
“There’s a lot of complexity in the plant to manage that, but it gives you enormous flexibility to follow market trends, so you’re not locked in to just selling a certain type of car if that market starts to evaporate.
“So we thought, ‘well how do we take advantage of that kind of key strength in the Australian industry?’. And we thought, ‘well, we’ll do a sort of proof-of-concept project around trying to use pre-existing vehicle architectures that are here in Australia and try and design it in a way that took advantage of the strengths and flexibility of its local industry’.
“We also wanted to demonstrate the attractiveness to customers to develop electric vehicle engineering skills here in Australia. You can’t have manufacturing if you don’t have design skills and technical background to manufacture a car.” Mr Olding described the Commodore EV project as a transitional strategy that could lead to locally manufactured electric vehicles of all sizes.
“If you look at the Tesla Model S, which is a ground-up electric car, the actual layout of the technology is identical to this. The geometry is different, but the basic layout is the same, so to us that was kind of confirmation that using this sort of vehicle is a nice transition strategy.
“You can make both kinds of vehicle off the same architecture, but ultimately it gives you the direction of what a ground-up EV should be, so what happens in 10 to 20 to 30 years? “It depends on the size of the market and the degree of investment you’re willing to make … but the possibilities are there.” He said that, regardless of the future of the Commodore project, his company’s expertise in EV Engineering would put it at the forefront of EV development in Australia.
“We’ve developed a lot of capability along the way. We want to become an electrical vehicle engineering services company going forward, so after this project if anyone wants an electric car built, come to us.”
