Day 10 Stack the Lithium Ion Battery

Today all 26 Lithium lon batteries are stacked in the car in four piles. These are the Nissan Leaf battery modules. It all fits very well.

It is expected to take a few more days to complete this car. The battery parts are ready but it does not work yet. It needs to be connected and protected. Protection relates to overheating, charging, the correct output to the motor, but also the physical protection and preventing anyone to touch the battery. To keep the battery in good health it needs a Battery Management System (BMS). The BMS is a little computer that measures the battery cells. The BMS in this car will connect 13 sets of battery modules. It is basically a flexible setup and you can configure (stack and connect) the battery to fit for purpose. This car needs output from the battery to a 96V motor. With 13 modules in series each 8.4 V will provide a maximum of approx. 109.2V output. So this is 13.2 more than the motor needs but a little more voltage to the motor should be fine. I hope it is true. The calculation of cells versus modules is confusion and this is how I understand it; each Nissan leaf module consists of 4 cells internally and each of those four cell is 4.2 volt and connected in series and in parallel within the module. See Picture below of one Leaf battery module.

These Nissan Leaf modules cost approx 200 each. In Australia these modules are not available and the only distributor we currently know is Graeme in the Gold Coast who gets them shipped from the States and you can expect at least 2-3 months delivery time. Most of the batteries are used, I was lucky to get a pack of unused and I expect they will last at least 60,000 - 80,000 km (but it is a calculated guess as I don't know the efficiency of the car yet). The maximum battery capacity expected is 13kwh. For your comparison, a Tesla S has 85kwh.