TOSA Bus Flash Charges In 15 Seconds – Video

JUN 23 2014 BY MARK KANE 10

TOSA connecting to charging bay

TOSA connecting to charging bay

Project TOSA, which stands for Trolleybus Optimisation Système Alimentation, was launched in Geneva, Switzerland over a year ago when an electric bus from ABB Sécheron began service.

The unique feature of this vehicle is the time of flash charges of just 15 seconds at 400 kW on a fast charging stations (via 3 kWh ultracapacitors to not disturb the grid, which is just ~50 kW).

This flash charge is enough to allow the bus to go to another bus stop, but to fully recharge the bus need 3-4 minutes of charging at the end of the route.

The demonstration bus itself is 19-meters long and can carry up to 135 passengers.

To commercialize this concept, there is strong need of optimization of battery pack sizes for different routes, number of vehicles, number of charging stations and available power. But in the end we would have a bus with virtually infinite range within electrified routes.

“TOSA is the first full electric articulate bus that runs without overhead lines. With its so called “flash charging”, it recharges at the bus stops along the route in a record time of 15 seconds.

EPFL researchers have developed a mathematical model to optimized the costs of a prospective bus line using TOSA technology.”

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10 Comments on "TOSA Bus Flash Charges In 15 Seconds – Video"

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Are ultracapacitors really used in the charging station, or batteries? Seems like that would take a lot of ultracapacitors.

As noted by Brian, below, only one 3 kWh ultra-capacitor would be much more than enough at each charging station. I guess they want to have more than the 1.67 kWh needed, in case, is special circumstances, the bus consumes more to get to the charger (extra cold weather, …).

It might be different at the end of the line. There you might not need any ultra-capacitor, since you have anyway a few minutes of staying, enough to recharge at 60 kW or so (see comment below).

Since the bus stops anyway a few minutes at the end of the route, and could charge completely there, it seems a costly and unnecessary luxury, to me, to have extra chargers along the route.
But since “EPFL researchers have developed a mathematical model to optimized the costs of a prospective bus line using TOSA technology”, I’m sure they’ll know better.
It may make sense in the case of many buses using them.
Then, after finding the best TOSA solution through that mathematical model, I think it should be compared with other options available, like BYD long range buses.
Which one is more convenient? Only a detailed mathematical analysis can reveal it.
Certainly the idea of saving on batteries, until they become very cheap, is quite alluring, to me. But again, one needs to know all details (cost of batteries, cost of chargers, …).

I read it differently… That the quick charge stops allow the bus to fully recharge at the end of the route by stopping for only an additional 3-4 minutes.

I’d guess that the 1.67 kWh they get from each flash charge (400 kW, 15 s) is much more than enough to cover the trip from one station to another (BYD buses would make about 1.5 km with that charge, if I remember correctly). So, in that case, they would not need to charge for 3-4 minutes at the end of the route (15 seconds would be enough), unless they don’t put any charger in the last few stops. But apart from what they’re doing, I think the best solutions might be either keep the battery on-board as small (capacity-wise) as possible, to save on them, and therefor flash charge often, or save on the chargers and install them only at one or both ends of the route. In the latter case the battery might have to be about 10-20 times bigger. As I was saying: to know which solution is best, I think one has to make detailed calculations, knowing all costs. Examples: Solution 1: the battery could be just 5 kWh (!!!) Start full, spend 1-1.5 kWh till next charging station (which doesn’t have to be at the next station – a few could be skipped) and get… Read more »

“The unique feature of this vehicle is the time of flash charges of just 15 seconds at 400 kW on a fast charging stations (via 3 kWh ultracapacitors to not disturb the grid, which is just ~50 kW).”

These numbers are confusing to me. There seems to be more to this story…

15 seconds at 400kW is only 1.67 kWh. Why would they need 3kWh of capacitors? I assume the caps recharge from the grid at up to 50kW? So this means that they actually only have to add 350kW on top of the 50kW from the grid, which for 15 seconds is 1.5kWh. So with 3kWh they could charge two busses back-to-back in 30 seconds. Is that ever necessary? How often would you be able to get two busses in/out of a stop within 30 seconds?

If the supercaps discharge at 350kW, and recharge at 50kW, it takes 7x as long to recharge as to discharge. So for every 15 second discharge, it takes 1:45 to recharge for the next bus. Even during rush hour, this seems like a lot of throughput to me for a typical roadside stop.

To ABB (not related to buses):
please stop installing 50 kW stations… and install 100 kW (or more powerful) ones, instead, with two connectors for each standard supported.
That will allow two cars to charge at 50 kW at the same (two parking spots should of course be powered by each station), thus alleviating “charge anxiety” (fear of finding the charger occupied) and will also allow faster charges (at 100 kW – that I believe are supported at least by CCS standard (cables support more) – not sure about CHAdeMO) by existing or future EVs.

(You bought Epyon, the Dutch company that used to make 250 kW with 4 plugs, potentialy supporting any standard and combinations of charging powers. But you’re not istalling those. Such a pity! Please do so!)

Better still: install 150-250 kW stations (with multiple cables) that also support the Superchargers’ standard. Do something GREAT!!! PLEASE!!!

I know you’re just making the chargers, not installing them. But I’m sure you can convince lots of your customers (those who build charging networks) to go the way you recommend.

“Flash Charge” is the future…

A 400KW charger…that should be capable of adding ~180miles of range in under 10 minutes in a regular car. That would bring EVs on par with ICEV’s for long distance practicality. Some day in the not too distant future if Tesla has anything to do with it I imagine.