Hello everyone,
I am a part of an FSAE team and we're currently making our own 18650 battery pack which is divided into 5 modules that are connected in series. Each module having 22p6s cells. It is a 100V, 7.1KWh pack with average current draw of 250A and peak currents of 500A. Since the current draw is high, looking up the ampacity charts we'll require the busbar of the individual modules to be atleast 1.4mm thick made of copper. Due to this we cannot spot weld them using the locally available sunkko spot welders. Soldering is not allowed. So that leaves us to use clamped busbars on to the cells at both ends. I have a few questions regarding the same. I have attached my designs below
Through the empty holes bolts will pass that'll be used to clamp the busbars against the cell. The bolts will be insulated from the busbar using the FR4 sheet which will be machined in that manner.
1) Is there any data regarding damage caused to cells due to compression caused by clamping busbars.
2) How can I minimize contact resistance? I plan on using a 0.1mm copper sheet(used as gaskets) and then bolting on the thick copper busbar on to it which will result in better contact. Any concerns regarding this?
3)Any other better method or any suggestions?
I am a part of an FSAE team and we're currently making our own 18650 battery pack which is divided into 5 modules that are connected in series. Each module having 22p6s cells. It is a 100V, 7.1KWh pack with average current draw of 250A and peak currents of 500A. Since the current draw is high, looking up the ampacity charts we'll require the busbar of the individual modules to be atleast 1.4mm thick made of copper. Due to this we cannot spot weld them using the locally available sunkko spot welders. Soldering is not allowed. So that leaves us to use clamped busbars on to the cells at both ends. I have a few questions regarding the same. I have attached my designs below
Through the empty holes bolts will pass that'll be used to clamp the busbars against the cell. The bolts will be insulated from the busbar using the FR4 sheet which will be machined in that manner.
1) Is there any data regarding damage caused to cells due to compression caused by clamping busbars.
2) How can I minimize contact resistance? I plan on using a 0.1mm copper sheet(used as gaskets) and then bolting on the thick copper busbar on to it which will result in better contact. Any concerns regarding this?
3)Any other better method or any suggestions?