Prototype electric New Flyer transit bus powered by 120 kWh MHI MLiX Li-ion pack in operational testing in Manitoba, Canada
08 June 2012
An all-electric, battery-powered prototype demonstration bus under joint development by Mitsubishi Heavy Industries, Ltd. (MHI), the government of Manitoba, Manitoba Hydro, Red River College and New Flyer Industries Canada ULC has been completed and was recently unveiled in Manitoba, Canada. (Earlier post.) The bus will be demonstrated on the streets of Winnipeg over the next two years.
The 40-foot “E-Bus” is based on New Flyer’s 40-foot Xcelsior heavy-duty transit bus and is powered by a 120 kWh lithium-ion rechargeable battery pack developed by MHI. The $3-million electric bus project costs are split equally between the Government of Manitoba, Manitoba Hydro and Mitsubishi Heavy Industries.
The cells are MHI’s MLiX prismatic 50Ah, 3.7V cells (185 Wh-class). The MLiX batteries use lithium compound oxide (nickel, manganese, and cobalt) for the cathode material, along with a graphite anode, high-strength separator, electrolyte, and electrolyte additives to attain high voltage and high capacity, a high energy density to volume and weight, a high charge/discharge rate, and long life (3,500 cycles or more, 80% DOD @ 1C.)
Gravimetric energy density of the cells is 132 Wh/kg; volumetric energy density is 266 Wh/L.
The flat-plate stacked structure of the electrode achieves high charge/discharge rates, long life, and a high-level of safety by eliminating the stress difference generated at the inner/outer spiral electrode, and at small radius positions caused by electrode expansion/shrinkage, and the directional heat transfer (rolling direction only; seen in a spiral electrode), according to MHI.
MHI also makes a 20Ah cell using the same chemistry. The 50 Ah battery was designed to have a high energy density through the use of a conductive network with a proper dispersion of conductive materials, while the 20 Ah battery was designed to have a high power density for hybrid vehicles by reducing the internal resistance with an optimized electrode thickness.
Other steps taken to augment the capacity of the battery were adjusting the separator porosity, diffusing the lithium-ion in the electrolyte, and easing the insertion to the negative electrode through optimization of the conductive materials, electrolyte composition, and electrolyte additives.
The E-Bus project is being implemented under the Memorandum of Understanding (MOU) on Renewable Energy Development signed in December 2010 between the Government of Manitoba and MHI, under which the two parties agreed to collaborate towards realizing an advanced low-carbon society.
The agreement created the structure for a series of potential collaborative projects between Manitoba and MHI in eight areas: electrification of transportation and recharging infrastructure projects; battery-storage technologies; heat-pump technologies; advanced biofuels technologies; wind-energy technologies; energy-efficiency technologies and systems; solar technologies and silicon processing; and integrated energy production, storage and utilization demonstrations.
As the first step of the initiative, the partners have been working since April 2011 to develop and demonstrate a lithium-ion rechargeable battery-powered bus and recharging technology.
Going forward, the project will test the E-Bus’s compatibility in cold weather through actual operation. Also, it will contribute to the study of promoting electrification of transportation using electric powertrains such as lithium-ion rechargeable batteries, and establishment of recharging infrastructure, aiming to respond to the need for environmental burden reduction in the transportation field.
MHI views this project as a very important step for popularizing lithium-ion rechargeable batteries in the North American electric bus market, a market which the company expects to grow.
Resources
Daisuke Mukai et al. (2012) Development of Large High-performance Lithium-ion Batteries for Power Storage and Industrial Use. Mitsubishi Heavy Industries Technical Review Vol. 49 No. 1
I am sure it is wonderful, but I would stick in a 100 Kw generator as well as a range extender. A bus is big and should have lots of space for the gen + fuel etc.
You probably wouldn't use it very much, but if you had to do a long run (city to city, factory to station) it means you can just drive it and don;t need to start planning a charger route.
You just need enough power to cruise at 90-100 Kph.
Posted by: mahonj | 08 June 2012 at 03:03 AM
@mahonj:
Buses tend to have fixed routes, so instead of paying out more money on this bus to put in range extenders and so on you amortise capital more efficiently by tight specifications.
They have plenty of diesel buses they can use for longer routes.
Hopefully later diesel will become diesel/hybrid or fuel cell buses, but those would not need this very large and expensive battery pack.
It's nice that those batteries in a Leaf would raise it's EPA range to around 97 miles from 73 miles.
Slowly but surely battery energy densities are rising.
Posted by: Davemart | 08 June 2012 at 03:27 AM
Successful light weight BYD e-city buses use 243 Kwh battery packs instead of the (too) small 120 Kwh battery pack used on this bus. It will not have enough range between charges and will have to get 2 to 4 quick charges on every 8-hour shift.
Why spent research money to do less than what is already commercially available? This does not make sense.
Posted by: HarveyD | 08 June 2012 at 07:35 AM
Harvey,
It looks like the all electric buses they are using out between the La Verne and Pomona routes out in California has just 72kWh and makes it ok:
"Public transportation company, Foothill Transit, has purchased three of the buses and two charging stations from Proterra. The buses have 72 kW-h lithium-ion battery packs ... and provide the buses with three hours of running time or a range of 30 miles (48km). They come in 550lb (249kg), 18 kW-h modular units supplied by Altairnano.
The buses will be deployed on Foothill Transit’s Line 291, which travels between La Verne and Pomona, and they will recharge about every 30 miles at the Pomona Transit Center at a drive-in docking station"
http://www.gizmag.com/proterra-ecoride-be35-bus/16195/
So I assume the 120kWh must be fairly useful to them.
Posted by: DaveD | 08 June 2012 at 11:04 AM
@DaveD:
The Proterra buses use Alatairnano lithium titanate batteries which enable them to take a very fast charge i 10 minutes or so, so the cases are not comparable.
I agree though that no doubt they have thought through the capacity they need for the route in Manitoba.
Posted by: Davemart | 08 June 2012 at 12:01 PM
DaveMart,
Yeah, I'm a fan of rapid chargeable batteries for applications like this. I'd like to see a trial where they use something like those new Skeleton Skelcaps and REALLY rapid charge them at a couple of stops along their route.
But I'm afraid the price would still be pretty high. Right now, you can get the Maxwells in REALLY high volumes for about $15/Wh...so that would be like $1,500/kWh. If Skeleton could really drop that by 8x then you'd be talking something realistic.
Of course...I don't really believe Skeleton can get prices down to $187.5/kWh for Supercaps! I wish it, but then I also wish for a winning lotto ticket. Neither one is likely to happen.
Posted by: DaveD | 08 June 2012 at 12:50 PM
Try $15,000/kWh; you slipped a decimal.
Overhead contactor bars for charging at regular stops might be cheaper than big battery packs. This would break even a lot faster on routes with lots of traffic; it would be a natural for cities like Chicago and New York, not so much for low-density areas.
Posted by: Engineer-Poet | 08 June 2012 at 08:27 PM
Oh wow, you're right! oops :-)
Posted by: DaveD | 09 June 2012 at 09:06 AM
Yes, it would be relatively easy to install quick charging facilities (wired or wireless) at many regular bus stops to reduce the size and cost of on board batteries. One can wonder why it has not already been done!
Down town core areas with very heavy traffic may be a good place to start. Ideally, off drive path bus stops with charging facilities would be a better solution but it is not always possible to do.
Sometime between 2020 and 2030, when batteries energy density has multiplied by 5X to 10X and cost is down similarly, charging facilities at the end of bus routes will be enough.
Posted by: HarveyD | 09 June 2012 at 09:34 AM