fingers and busbars
On the surface of the solar cell, there are parallel lines called fingers and There are also other lines called busbars Let us briefly learn about these lines.
Fingers: The lines appearing on the cell surface.
They are very thin metal lines, whose main function is to collect and deliver the energy generated from the surface of the solar cell to the busbar as for the busbar that is orthogonal to the finger Its main function is to transfer the generated current between the solar cells within the solar panel.
Of course, this is just a small detail, but on the ground, there are many details, studies, and research on these two topics, but you, as an electrical engineer or technician working in the field of solar energy, only general knowledge is sufficient on these issues, as, for the in-depth exploration, it falls within the field of plate manufacturing.
The oldest types of cells used to come with 2 busbars are practically extinct and no longer exist, then after that, the companies produce cells with 3 Busbars then with 4 Busbars, and these days the most common panels produced with 5 Busbars but does this stoped here?
Of course not.
The latest types of panels technology now come in 6 Busbars and 9 Busbars.
LG had an opinion and started producing cells with 12 Busbars, but someone might say that increasing the number of bars is not good because it actually consumes the area of the cell, but the secret can be in two things:
1- the companies were playing on the subject of the thickness of the busbar and its shape, that is, with the increase in the number of busbars, the busbars thicken became less.
LG started producing busbars in a circular rather than square way but it is important to know that the increase in the number of bars means that its the best idea, and the increase in practice will be in the Fil factor and thus increase the (efficiency).
Of course, for the sake of ease of understanding the topic of increasing the number of busbars we give the following analogy :
For ease of understanding, imagine that you have a very busy highway with cars and the width of the road does not exceed 3 meters, within this data we will have a specified number of cars that pass through this road during a specific time, now if we have a soul busy road but 5 meters wide, will we have the same number of cars that cross the road? of course yes, the number of cars crossing the road increases because the width of the road becomes larger.
The solar panel is formed on the basis of a general rule, and it links the cells within the solar panel in series, i.e. it is an increase in voltage because the cell voltage is somewhat small and the solar cell cannot be used alone on the ground and thus several cells are connected to each other in order to form a chain of solar panels that are connected On the inverter.
Of course, this same rule can be applied to the chain of panels in order to form a string, but the important thing is to know what happens at the serial connection of cells or panels, And the diagram in the picture shows this topic for two cells that have been connected in series because the end result is the cell current and the sum of the efforts of the two cells and the same thing that we mentioned applies when connecting two panels in sequence, these things may seem simple but it’s a cornerstone or foundation that will depend.
The engineer or technician must on it when working in real life.