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Hello everyone,
I am working to solve an a connection type issue for a customer of ours. I work for a small family owned/operated business that produces OEM and custom small application solar modules. We have a customer who has an IoT application using a small solar panel to act as a Voltage Indicator.
Here is a rundown of the situation for context:
Previously, version 1 was hand built using FR4 board with straight wire wrap terminal pins hand inserted and bent. Then solar cells were shingled and taped to the FR4 substrate and tabbing wire routed to complete the circuit; connections then potted with 2 part epoxy. After that, mounting tape was added around the edges and a PET lens is applied.
V1 Front & Back View
View of Pins bent, installed, and solder capped to prevent push-through
View of layers and pins cut to length for install to PCB assembly board
Not cost effective and profit margin factoring in re-work, etc., was non-existent, practically at a loss. Quality of seal not up to standards and so on. In April of last year I sent samples of panels with performance figures similar to the previous version that was outsourced that used more cost effective methods of SMT and used PET lamination techniques. We have used this combination of methods with other custom panels, except this application uses a pin as it's connection type rather than wires added to the back contacts.
They had samples from April 2023, sat on them and neglected to do their due diligence, came time for them to submit a PO for 3,500 of them, quickly tested performance and gave the green light for production. After a couple weeks they come back asking us to stop production as they feel there is excessive solder at the base of the pin on the back of the panel. For them, this does complicate the vertical clearance of the panel at the pins causing the panel to be mounted at a slight angle rather than parallel to the assembly board.
Version 2 view of layers and solder at base of pin
The PCB substrate in V2 is considered one sided, pathway on the back of the panel, Non-plated Through Hole.
One way to approach it is to move pathway to solar facing side and/or make it a Plated Through Hole. This requires additional steps in terms of installing the pins and thus raises cost. Additionally, I believe it will further complicate how well the PET lamination layer adheres to the substrate. In the picture below, you can see where the lamination is warped around the pins. On a number of the panels we are seeing delamination around this area due to the lamination adhesives having less purchase on the substrate.
V2 Warping of PET around pin area leading to delamination
Final assembly board (White Rectangle is the mounting area for our panel)
Final assembly encased (Clear encasement is why vertical clearance is a concern)
I am looking for an alternative way to connect this panel to the assembly board.
As I see it there are a couple different ways to go about it.
- Plated Through Hole or double sided board, using same pin.
BUT... Delamination will still be a concern and can compromise quality. Pins are also likely to be discontinued in the future, as alluded to by the manufacturer....
- Create a stand off area for the contacts/terminals that is not laminated. This stand off area can utilize the typical contact type used in solar modules of this type seen in the picture, or can be a Through Hole of some type using a pin or other terminal type. (See EXAMPLE)
EXAMPLE Stand Off area w/ typical contact pads
BUT... The manufacturer I have outsourced to is not capable of doing a standoff area without lamination because the lamination has to be manually removed. OR, our customer doesn't want to adjust contact type/processing of their current assembly board.
My question to all of you is... What types of connections or otherwise alternative designs can you think of that are applicable? Do you know of any terminals that can do the job? Any other suggestions of how to approach the problems?
I have been searching and searching for a solution that solves multiple problems at once. I have a few candidates, but I want to reach out to the community and ask for some help brainstorming.... I have come across a variety of pins like the one below in a few different morphologies. I am concerned with cost and if material, like brass, of the pins would make it difficult to clip to size.
EXAMPLE Alternative pin candidate
Any and all help would be greatly appreciated! Thank you!
I am working to solve an a connection type issue for a customer of ours. I work for a small family owned/operated business that produces OEM and custom small application solar modules. We have a customer who has an IoT application using a small solar panel to act as a Voltage Indicator.
Here is a rundown of the situation for context:
Previously, version 1 was hand built using FR4 board with straight wire wrap terminal pins hand inserted and bent. Then solar cells were shingled and taped to the FR4 substrate and tabbing wire routed to complete the circuit; connections then potted with 2 part epoxy. After that, mounting tape was added around the edges and a PET lens is applied.
V1 Front & Back View
View of Pins bent, installed, and solder capped to prevent push-through
View of layers and pins cut to length for install to PCB assembly board
Not cost effective and profit margin factoring in re-work, etc., was non-existent, practically at a loss. Quality of seal not up to standards and so on. In April of last year I sent samples of panels with performance figures similar to the previous version that was outsourced that used more cost effective methods of SMT and used PET lamination techniques. We have used this combination of methods with other custom panels, except this application uses a pin as it's connection type rather than wires added to the back contacts.
They had samples from April 2023, sat on them and neglected to do their due diligence, came time for them to submit a PO for 3,500 of them, quickly tested performance and gave the green light for production. After a couple weeks they come back asking us to stop production as they feel there is excessive solder at the base of the pin on the back of the panel. For them, this does complicate the vertical clearance of the panel at the pins causing the panel to be mounted at a slight angle rather than parallel to the assembly board.
Version 2 view of layers and solder at base of pin
The PCB substrate in V2 is considered one sided, pathway on the back of the panel, Non-plated Through Hole.
One way to approach it is to move pathway to solar facing side and/or make it a Plated Through Hole. This requires additional steps in terms of installing the pins and thus raises cost. Additionally, I believe it will further complicate how well the PET lamination layer adheres to the substrate. In the picture below, you can see where the lamination is warped around the pins. On a number of the panels we are seeing delamination around this area due to the lamination adhesives having less purchase on the substrate.
V2 Warping of PET around pin area leading to delamination
Final assembly board (White Rectangle is the mounting area for our panel)
- The pins are currently 0.025" square posts for 0.042" through holes
Final assembly encased (Clear encasement is why vertical clearance is a concern)
I am looking for an alternative way to connect this panel to the assembly board.
As I see it there are a couple different ways to go about it.
- Plated Through Hole or double sided board, using same pin.
BUT... Delamination will still be a concern and can compromise quality. Pins are also likely to be discontinued in the future, as alluded to by the manufacturer....
- Create a stand off area for the contacts/terminals that is not laminated. This stand off area can utilize the typical contact type used in solar modules of this type seen in the picture, or can be a Through Hole of some type using a pin or other terminal type. (See EXAMPLE)
EXAMPLE Stand Off area w/ typical contact pads
BUT... The manufacturer I have outsourced to is not capable of doing a standoff area without lamination because the lamination has to be manually removed. OR, our customer doesn't want to adjust contact type/processing of their current assembly board.
My question to all of you is... What types of connections or otherwise alternative designs can you think of that are applicable? Do you know of any terminals that can do the job? Any other suggestions of how to approach the problems?
I have been searching and searching for a solution that solves multiple problems at once. I have a few candidates, but I want to reach out to the community and ask for some help brainstorming.... I have come across a variety of pins like the one below in a few different morphologies. I am concerned with cost and if material, like brass, of the pins would make it difficult to clip to size.
EXAMPLE Alternative pin candidate
Any and all help would be greatly appreciated! Thank you!
