Thermal vias for high current pads

[vinodkaruvat]

Hello,

I am designing a board which draws in abt 22Amps from a LiFePo4 battery.
there are 2 things here. The board is a 4 layer board.

1) I don't want any connectors to the board for the Vcc and Gnd. I am soldering the wires (Vcc_bat and Gnd_bat, wires from battery) to the Vcc and GND of the board directly. Now, what is the drill for these holes ? It is supplying almost 22-23Amps peak. This is mainly sourced to the internal plane (Vcc). What is the suggested drill dia ?

2) Now, the question of thermal vias. Sincew I am soldering them, I guess i will need thermal vias. Right ?


Regards,
Vinod.

 

[kspalla]

Thermal vias is to transfer heat from one layer of the pcb to the other side of pcb which might in good contact with metal body.
if the battery is getting heat while discharging and it must be cooled in your case I assume.
i also assume battery is placed betwwn pcb and you want to tranfer the heat from battery to outside case. is my understand is correct?

 

[vinodkaruvat]

Thank you for ur response.
Ur understanding is right.
For heat to be dissipated I intend to use a solder mask free copper.

But, my doubt is ,what is the drill dia that I need to connect the 22Amps wires to my board ?
The current will be on for only some time and not continuous.

Vinod.

 

[kspalla]

R U worried about heat or on 22A current?
is this current passing through wires or you want to use mask free copper layer on PCB?

Regards.

 

[Mattylad]

For 22A I would more consider putting a bolt through the board, using washers either side and done up tight, then ring connectors on the end of the cable.

If you are just soldering them then what size cable?
Make the hole big enough and plated with a large solder resist free area surrounding them and use a high wattage iron.

I would not thermally relive them at this current.