Solar power panels | Perc cell structure

3 months ago

Solar power panels | Perc cell structure. More and more consumers are betting on these panel system with a high capacity. They use so-called PERC technology for increase efficiency. As a result, the newest photovoltaic PV panels deliver more yield with less light conditions.

This way, you get more energy out of your installation, even in cloudy weather. How does the technology work?

Solar power panels | Perc cell structure

How a typical PV panel works (without PERC).

To properly understand how the latest solar PV panels work, we first explain how you generate renewable energy with ordinary panels. In this way, you will better understand what PERC delivers.

The sun's rays consist of different parts, including photons, a kind of small packets of energy. Solar panels capture those photons first, after which they "change" into electrons. If there are too many electrons on one side of the panel, they will change position. It changes the voltage and starts a current.

If you look closely at a PV cell, you will see thin wires. They capture the jumping electrons and guide them, via an inverter and the meter cupboard, to your outlet.

The operation of PERC: passively made back

Average standard PV cells have a fully conductive back. That is, it allows energy through the entire surface. PERC cell technology are made partially passive with the help of non-conductive lines. The name or abbreviation of the technique says it all: Passivated Emitter Rear Cell.

Why does it ensure a higher yield?

As you know, sunlight consists of all kinds of particles: photons. They all have different wavelengths. Photons with a shorter wavelength (blue light) convert most easily into electrons — a necessary process for those who generate solar energy.

Unfortunately, clouds filter those "easy" photons from the sun's rays. What remains are the photons with a longer wavelength (red light), which sometimes "escape" before they turn into an electron. That does not make you happy: your installation will deliver less.

Cells with PERC technology, you have much fewer problems with "escaping" photons. The back reflection into the cell on the non-conducting lines of a PERC cell. This gives them, as it were, another chance to "change" into an electron.

That is beautiful. Because the more photons convert into atoms, the more you benefit from your solar electricity systems installation.

The sales results.

The turnover of cheap brands often rises faster than that of premium brands. But in the world of solar PV systems, something else is going on. The customer who wants to buy photovoltaic panels does not know the brand names. Price, therefore, seems to have become decisive too often.

At the same time, the high efficiency and energy output of PV panels keep increasing, partly due to the advance of perc technology.

Where in 2015 the annual production of photovoltaic panels with perc silicon cells was only 5 gigawatts peak. The most recent estimate by research agencies shows a production capacity of a 35-gigawatt peak at the end of 2018. That is roughly one-third of the global production capacity based on perc technology.
It, therefore, seems only a matter of time before these panels installations with perc technology will have over 50 percent off the market.

Thanks to this technology, the power output is polycrystalline modules increased to 295 watts peak. That of monocrystalline modules up to 325 watts peak, and those of one
monocrystalline PERC module up to the 370-watt peak.

PERC stands for Passivated Emitter Rear Cell.

Freely translated: passively made backside of the cell. This technology is relatively easy to fit into existing solar cell production lines. Therefore already being used on a large scale. It is not a radical new technology, but a small improvement in the technologies manufacturing process.

Because it is only 2 mm thick, a lot of sun radiation shines through the cell directly onto the aluminium foil. The foil absorbs this radiation. With the new technology, an extra layer is applied between the cell and the aluminium foil, the so-called PERC layer.

This layer ensures that incoming radiation from the sun is reflected in the cell and can still contribute to the generation of energy. Besides, by applying the PERC layer, the cell can absorb a broader spectrum of sunlight.

With the light, the PERC technology ensures more yield. And that's great because the more energy is extracted from it, the better. But it also has another advantage. Less energy is converted into heat. The warmer it becomes, the less it will perform.

A normal cell gives 0.4% less efficiency per degree that it gets warmer. The disadvantage is that it has less capability, the energy is converted back into heat. As a result, you guessed it has less return A vicious circle. They also gives a better return even in cloudy weather, when there is no direct sunlight.

The solar industry already offer these PERC panels.

From Wikipedia:

Passivated emitter rear contact (PERC)[18] consists in the addition of an extra layer to the rear-side of a cell.

Produce electricity for battery backup or exported to the grid with a high feed in tariff.

All this works with standard installed solar inverters. You do not have to change anything. The same garanty is offerd, about 25 Years.

The most beautiful off all this is, that they are 10% more expensive and the generate electricity is 20% more. Nice investment for your electricity bill!