Reverse Engineering an onboard charger PCB

[edson]

Hi all, the picture attached shows what people call a "waffle plate" which is found inside the Nissan Leaf's onboard charger. This part is known to fail and unfortunately very difficult to find a replacement for or repair. The PCB is potted with epoxy, which at this point is completely hardened and basically impossible to remove. Some people have x rayed the piece and have come up with schematics for the board. Attached is also the schematic. I can draw the schematic myself in KiCad, but there are a few things I don't know how to do. For instance, the bottom of the board has an aluminum plate(wiped clean in the picture), that is normally coated with thermal paste. I have no idea how this plate is attached to the PCB? on the top side of the you can also see some spacers(one in each corner and one in the middle) which seem to be pressed in? My questions are:

1. How is this aluminum plate attached to the PCB? Is it a normal manufacturing process that can be requested at the time of the PCB fabrication?
2. Does anyone know what type of pins are the ones sticking out of the epoxy on the top side? these pins are inserted and soldered into another PCB normally stacked above this one.

[johu]

Hi, you can attach pictures now

[jerrykco]

I always forget how to attach. You need to enable the full editor then there is an attach icon.
I have all the boards from the charger if you want them. I was going to recycle the aluminum case.

[edson]

I always forget how to attach. You need to enable the full editor then there is an attach icon.
I have all the boards from the charger if you want them. I was going to recycle the aluminum case.

I would love to have the boards, I'll send you a message

[jrbe]

Is the aluminum very soft? Any chance it's a single layer aluminum PCB?

The tubes look to be smd standoffs. If the aluminum plate is separate, they could be pems standoffs but it doesn't look like a normal pem standoff.

The male headers look like a board to board spacer header with a spring in the middle. Might be OEM over engineering for vibration.

Looks like the injection molded "spider" slides over the spacer tubes to hold the potting compound.

Do you know what starts the failure? Looks like heat / bad connection.

[johu]

Which version charger is this from?

[jerrykco]

2011 I think he said in messages to me. Mine was 2015 and therefore of no use to him.

[celeron55]

It seems this part can be found in the gen1 Leaf, in which the OBC is located behind the rear seat. The ones after 2013 or so which we call gen2 have the PDM under the hood, which contains the OBC, and that doesn't have any potted transistors, it's all quite repairable.

[edson]

Which version charger is this from?

It's from a 2012 Leaf. 2011 and 2012 have the same onboard charger

[edson]

Is the aluminum very soft? Any chance it's a single layer aluminum PCB?

The tubes look to be smd standoffs. If the aluminum plate is separate, they could be pems standoffs but it doesn't look like a normal pem standoff.

The male headers look like a board to board spacer header with a spring in the middle. Might be OEM over engineering for vibration.

Looks like the injection molded "spider" slides over the spacer tubes to hold the potting compound.

Do you know what starts the failure? Looks like heat / bad connection.

You know what... it might be a single layer aluminum PCB. Will try to look more into it this week. I'm not sure what starts the failure. Some people suspect a weak 12V battery could lead to this. It's a very common issue in the 2011-2012 Leaf. Nichicon did many iterations on the charger. 2013 and newer leafs have a different design