Lithium Ion Battery Supplier

[aep9690]

Hey,

I'm part of an electric vehicle club at my school.  In the fall we plan on partnering with the schools formula SAE team to build an electric car.  I'm trying to come up with a source of lithium ion batteries.  The battery pack needs to be along the lines of 240V at 10Ah.

There are a lot of places to get lithiumj ion batteries at that current, like hobbyking and the like, but I was hoping to find some place that will give discounts for larger orders, or is more reputable.

Thanks

[Psi]

Hobbyking will probably give discounts for large quantities but you'd have to ask them.

I noticed powerstream have lithium batteries and even make up lithium packs to order
http://www.powerstream.com/b.htm

I've never bought from them before though.

[marshallh]

batteryspace.com

[IanB]

The battery pack needs to be along the lines of 240V at 10Ah.

Wow, that's a lot of batteries. I think the battery management electronics around that kind of pack are going to be...interesting...

[richcj10]

We use these style of cells all the time. From electric cars to robots.

http://www.batteryspace.com/LiFePO4-Prismatic-Module-3.2V-20-Ah-10C-Rate-64-wh.aspx

[peter.mitchell]

check out the endless sphere forums.
http://endless-sphere.com/forums/index.php

[BravoV]

With that kind of quantities, I'd expect the battery manufacturers themselves will eagerly to respond to your inquiry regarding a proper procurement process. A simple emailing them should be a good start.

[metalphreak]

We used ~600 "C-Cell" sized LiFePO4 batteries in our FSAE car. We had someone else do all the cell tag welding 

Hobbyking batteries are not a good idea. They are soft packs, and really aren't designed for combining into such a large scale. I would also remind you that 240V dc is lethal if handled incorrectly.

I would be looking at batteries used by others in proven designs. There's plenty of places out there that sell large high capacity cells.

[Rasz]

check out

[aep9690]

Thanks for the help, I'm going to look into these.

Rasz, I'm actually a part of the schools IEEE organization and we are working on a van that uses 150 thundersky battery modules.  The reason I am hesitant to use them is because they are very large and heavy.

[metalphreak]

A few of the cars we have use those yellow batteries. Thundersky does sound familiar but I'm not sure if they were that brand. A couple of them have failed and expanded/puffed. I wasn't involved with them so not sure if they were over-discharged or mishandled.

http://therevproject.com/vehicles/sae2013.php There's a photo here of the pack. There's two of them in the vehicle.

[NiHaoMike]

Just find some old Prius batteries.

[aep9690]

Thundersky may have changed their name at some point.

[TheRevva]

I'm part of an electric vehicle club at my school.  In the fall we plan on partnering with the schools formula SAE team to build an electric car.  I'm trying to come up with a source of lithium ion batteries.  The battery pack needs to be along the lines of 240V at 10Ah

Let me do some quick 'cigarette packet' math here (as I think I am going insane?)
240V at 10A = 2400VA which is somewhere surprisingly close to 2400Watt?
Now, I'm an 'old fart', so I still have a brain that works in old fashioned horsepower.
1HP is about 748 Watt (let's round that off the 750Watts to make it easier).

Am I correct is thinking you're trying to build a 3HP car?  Good luck with that!

Perhaps you're intending consuming batteries at a much greater rate?  Let's get really radical and jump up an order of magnitude to 100 amps.
You've now reached a fairly ACCEPTABLE 30HP output which will at least get the car moving about.
But there's a slight problem I see in doing this.  Your battery pack will be somewhat flat before you get to the end of the driveway (let alone around the block).

One of my ummm 'hobbies' was an involvement in the drag racing scene.  When I was living in the states, I was intrigued by a group named NEDRA (National Electric Drag Racining Association).  These guys have since been merged into the more traditional NHRA drag racing fraternity .

The controllers they use on these suckers are rather impressive such as the 'zilla' controller.  At the top end, it is switching a couple of KILO-AMPS at over 300Volts!!!  (Think of some SERIOUS IGBT transistors in there doing the switching!).  They don't use cables much.  Instead, it's thumping great lumps of copper bus bar!  They need to run some BIG fans on the commutator of the motor as the plasma production is rather prone to cause some minor ummm 'shorting' issues (and when you have a short on a 500kW power source, things get rather warm in a BIG HURRY.

Last I heard, they've got these suckers running 1/4 miles in just under 7 seconds which is still quite a lot slower than the fastest piston based vehicles (4.5 seconds or so).  One of their stumbling blocks is that as the motor reaches high RPM, the back EMF is progressively more difficult to overcome.  They often use a PAIR of 12V motors (albeit with a 'special' wind), and they take off from the line with the two motors in SERIES across the 300+ volt supply.  Part way through the run when the back-EMF becomes excessive, the two motors are switched from being in series, to being in parallel (simply so that the controller is still able to jam in more amps).

Anyway, you might want to consider 'up-rating' your battery pack(s) somewhat if you want to get anywhere decent.

[aep9690]

We are still throwing around performance values, but the idea right now is to try and figure out about how much storage we need.  A lot of 3Hp engines need about 200-240VAC at about 6 amps to run.  Theoretically we could run something like this with 6Ah batteries, but in the real world we don't intend to be running at maximum capacity all the time, and we would like to get some good run time with it.  It is true that 2400W is a lot of power, but you tend to get up there when you are dealing with electric vehicles.

We are still new at this so we don;t want to do anything too crazy, we want a good proof of concept then we'll move on to the crazy stuff.

[metalphreak]

240V @ 10Ah

That's not the same as 10A  10Ah is the battery capacity.

The latest UWA vehicle has 4x 10-15kW motors in it. Peak currents can be up to 1000A (250A per motor) or higher. You only pull that current during hard acceleration, and for FSAE competitions, you don't really drive hard for more than perhaps 10-15mins.

3HP isn't going to move a 400kg vehicle around very fast at all... A typical 250cc motorbike has ~20hp and weighs far less.

[aep9690]

I was aware the the Ah rating is the capacity, not the discharge rate. 

3HP wouldn't get us going really quickly.  We are using one of these in our electric motorcycle.

http://www.electricmotorsport.com/store/ems_ev_parts_motors_pmg132.php

I guess we could use two of these to drive to car.  Or we need to find a larger motor.

[peter.mitchell]

No, really, seriously check out http://endless-sphere.com/forums/index.php

[aep9690]

Will do