September 17, 2014

Battery boxes

I had the battery boxes manufactures by IB Svets in Umeå. This is a small welding company specialized in aluminum welding. The boxes are made of 3 mm aluminum which makes them very sturdy.
I will glu and rivet the boxes to the frame. This way I will not compromize the frame by welding, and the combined glue and riveting will hold for accelerations of 44 g vertical and 210 g horizontal! This is a factor 10 compared to the requirements. Of course the accelarations to accomodate for are not achived by the motor, but from braking and rolling the car in case of a crash.
The battery boxes are insulated with 10mm foam (camping mattress) to reduce the cooling in the winter.

First test mount of the rear battery boxes



The rear seats still fit!

And the trunk space is preserved

Time to grind the surfaces of the frame where the boxes will be glued



The boxes with insulation, connections and battery cells



The battery cables are kept in protective tubes. These are ordinary construction tubes painted orange.

The "drive shaft tunnel" has lots of space for the battery cables. The short black tubes are heat shrink that will eventually cover the cable glands

Posted by at
Labels: , , ,

4 comments:

  1. UnknownSeptember 17, 2014 at 11:32 PM

    Wow you are really making progress with the battery boxes, superbly nice!

    ReplyDelete
  2. truecyborgSeptember 19, 2014 at 12:29 PM

    Thanks, ESA!

    ReplyDelete
  3. LukasOctober 4, 2014 at 12:43 PM

    Wonderful job - so rear cabin retains full useability! How will you control battery temperatures under the rear seats? Will you make another sheet to go under the battery boxes for better aerodynamics? What is your total kwH capacity now?

    Cheers

    ReplyDelete
  4. truecyborgOctober 7, 2014 at 11:01 PM

    Thanks Lukas!
    Yes you will not be able to see in the inside that it is an electric car (apart from the odd volt/amp hour meter and the red emergency cutoff that is ;)

    I am not planning to heat the batteries. I'm hoping they will perform well enough with just the 10mm insulation. My plans are to have the car in a heated garage at night where it will also be charged in temperatures above freezing. From what I have been reading these LiFePO cells do not get hot during discharge either so cooling is not needed.
    Yes, I am thinking of putting a sheet of ABS to cover the drive shaft tunnel all the way from the engine compartment to the frontmost battery box to improve aerodynamics. That will also protect the cables to some extent. It is not really possible to cover the space between the boxes since the rear axle is there moving up and down with the suspension.
    The total energy now is 65 cells x 100 Ah x 3.2V nomial = 21 kWh.

    ReplyDelete

Subscribe to: Post Comments (Atom)