How long do the solar cells last?

Aptera Community Aptera Discussions How long do the solar cells last?

Aptera Community Aptera Discussions How long do the solar cells last?

  • How long do the solar cells last?

  • Hayden Rank

    Member
    April 11, 2022 at 11:42 am

    From what I understand, photovoltaic cells work by taking energy from the sun and using it to knock the electrons off a substance with a low ionization energy (such as silicon) to create an electrical current. Although there is an extremely large number of electrons contained within every cell, the cell will stop working after every single electron has been knocked off. How long do Aptera’s cells last? And have we found a way to fix this problem? Most solar panels last around 25 years before being depleted of electrons and, while this is more than enough for a lifespan of a vehicle, I am curious nonetheless. Thank you to whoever can provide an answer.

  • John Malcom

    Member
    April 11, 2022 at 12:04 pm

    There are several well qualified solar engineering people on the forum. I hope they see your post and will respond.

    Aptera is using a very high quality solar cell. The solar cell manufacturers continue to work to improve both yield and life of cells and experiment with different cell compositions to provide the best cells at a reasonable price.

    Aptera will not do this basic kind of research but will monitor solar cell development research and production to insure we get the best cells at the lowest price when available for a production iteration.

    Aptera has not yet announced the solar warranty as they have not completed solar testing. When they do I think you will be pleasantly surprised.

  • Alain Chuzel

    Member
    April 11, 2022 at 1:34 pm

    Your understanding of how photovoltaic cells work is not quite correct. I just did a quick search on YouTube for “how do solar cells work” and found the following 5 minute video that I would like to recommend you watch. Rest assured, there are no electrons lost or harmed in the process!

    Strictly speaking, the CELLS Aptera is likely using can last a very, very long time. Many, many decades. What won’t likely last as long are the materials used to, ironically, protect the solar cells. I’m speaking primarily of the encapsulation. It will “degrade” over time by exposure to mother nature. The degradation usually manifest’s itself in the form of “darkening” and even “hardening” of the encapsulants.

    I’m happy to discuss further if you’d like!

    • Hayden Rank

      Member
      April 11, 2022 at 3:32 pm

      Ahh it is great to know that the electrons are reused! I assumed they worked something like an alkaline battery. So my new understanding is this, the cells are made of a metal with a very low ionization energy. The electrons are knocked out of orbit and and form an electrical that does work. The electrons then return to a silicon atom and the process repeats. Is this correct?

      • Alain Chuzel

        Member
        April 11, 2022 at 6:24 pm

        Hayden, I promise to get back to you tomorrow (Tuesday). I’m rather “spent”……

      • Alain Chuzel

        Member
        April 12, 2022 at 6:13 am

        Hayden, If you haven’t already, I’d like to recommend you take a look at Danny Mattijetz’s comment below (dated April 11, 2022 at 8:16 pm). I think it does a great job of addressing your question!

    • John Malcom

      Member
      April 11, 2022 at 5:53 pm

      Thanks Alain. A good basic video for those not familiar with the operation of solar cells. Is it correct that the efficiency of silicon cells maxes out in the low 20s percent and the cells selected by Aptera are at the higher end of that efficiency?

      • Alain Chuzel

        Member
        April 11, 2022 at 6:22 pm

        No worries John. I invite you to check out the following Wikipedia page regarding the maxing out of single junction silicon solar cells:

        https://en.wikipedia.org/wiki/Shockley%E2%80%93Queisser_limit

        Regarding Aptera’s cells, they are still the “champions” in terms of what single junction silicon are available today. They are generally available up to about 25.4% (at Standard Test Condtions (STC).

        • This reply was modified 2 months, 3 weeks ago by  Alain Chuzel.
        • John Malcom

          Member
          April 11, 2022 at 6:43 pm

          Thanks again for the tutoring!

  • Francis Giroux

    Member
    April 11, 2022 at 1:34 pm

    Solar Panels do not “lose” electrons. The electrons are knocked loose by the high energy photon, that’s true, but once loose they travel the completed circuit back to the panel as a low energy electron, and back into the matrix. How long do solar panels last. I purchased (used) some of the first solar panel built. They were used for a research project and then stored for decades. They still worked when I bought them and they still worked when I sold the property I installed them on. I would guess that solar panels will last similar to how Lithium ion batteries last. They will get less effective over time but still work at a lower output. So technically the last until you break them.

  • John Young

    Member
    April 11, 2022 at 4:39 pm

    These are the cells they are using.

    https://www.amazon.com/Sunpower-Flexible-Monocrystalline-Tabbing-Efficiency/dp/B078K5Y4PD/ref=sr_1_8?crid=2YF40ESGRDSHG&keywords=Sunpower+Flexible+Solar+Cells+E60&qid=1649720162&s=lawn-garden&sprefix=sunpower+flexible+solar+cells+e60%2Clawngarden%2C92&sr=1-8

    I bought some to make a little solar panel to charge my electric scooter. Yes, I could have bought ready made panel but I wanted to try and build my own. They bend, but not much. Broke a few playing around with them. Eventually covered them with some epoxy. Probably lowered the efficiency but they still do the job.

    • John Malcom

      Member
      April 11, 2022 at 5:55 pm

      John. Thanks and kudos for DYI

    • Alain Chuzel

      Member
      April 12, 2022 at 6:42 am

      Glad to hear of your experience with the DIY solar panel! Thanks for sharing.

      Here’s a pic of one of mine. (no it’s not a solar powered trash can!)

      • This reply was modified 2 months, 3 weeks ago by  Alain Chuzel.
  • M T

    Member
    April 11, 2022 at 6:15 pm

    Even low end monocrystalline based panels offer a 10year/80% output warranty. Higher end panels can offer 25 year/80+%. The real timeline will be encapsulation/physical damage here. The cells will work for a long time, if they are kept dry. I suspect expoxy coating UV damage and impacts/rocks/hail will drive the lifespan.

    • Alain Chuzel

      Member
      April 12, 2022 at 6:09 am

      Very well put. With respect to solar cell encapsulation, epoxy is generally avoided because of it’s susceptibility to UV degradation. I’m reasonably confident it won’t be used on the top side of Aptera.

  • Danny Mattijetz

    Member
    April 11, 2022 at 8:16 pm

    When thinking about the solar cell sandwich that was shown in the video, think about a perfect matrix of silicon throughout the whole sandwich. Everything lines us correctly and every possible bonding point is filled. Phosphorus has one more electron than silicon, so when it is added to the top layer, the matrix gets a little out of whack. That extra electron is kind of hung out to dry. The opposite is true of the Boron on the bottom layer of the sandwich. It has one spot that has a mismatched bonding point. The result is a permanent electric field across the sandwich. As electrons are freed, they feel this field and move in whatever direction it points. This causes them to move up to the metal contact points. The electrons do not come from the metal. The metal merely connects the top to the bottom of the sandwich. A freed electron can only move to the original spot by taking the long way around. This makes a full electrical circuit.

    An interesting point is that the photons coming from the sun or any other source of light, have to be of the exact wavelength to knock the electrons out of orbit. This is a quantum effect. If the energy of the photon is too much or too little, it does not free the electron. Many of the photons can go right through the sandwich without changing. This is how a multi-junction cell might work. By doping the top and bottom layers of a second sandwich so that it responds to a different wavelength, it can be positioned above or below the first sandwich to absorb those photons. The combined effect creates a more efficient cell than either one by itself.

    That last paragraph was just for interest. The Aptera cells are single sandwich cells.

    • Alain Chuzel

      Member
      April 12, 2022 at 6:06 am

      Great summary Danny!

      One comment/question if you don’t mind. I am under the impression that an electron would be freed as long as the incoming photon had AT LEAST (rather than exact) the amount of energy required(?)

      • Francis Giroux

        Member
        April 12, 2022 at 7:39 am

        That is my understanding as well, which accounts for the excess energy given off as heat.

      • Danny Mattijetz

        Member
        April 12, 2022 at 9:47 pm

        You bring up a good point, and I will admit that it has been almost 50 years since I studied quantum physics, but I believe the photon must have exactly the right amount of energy or quanta to eject the electron. Photons can still hit atoms and cause them to vibrate. That would result in heat. Another heat loss would be electrons recombining with their newly created hole before moving away from the atom. In recombining, a new photon will be created that will travel in a random direction and probably hit other atoms. That would also result in heat. Despite having said this, I’m not going to insist that I am right on this point. The memory cells fade after 50 years of not firing.

        • Alain Chuzel

          Member
          April 13, 2022 at 6:58 am

          Memory cells don’t fade. They just graciously give off a photon then drop to a lower orbit. 🤓

  • Patrick Liebknecht

    Member
    April 12, 2022 at 12:33 pm

    I read an article that said the newest solar cells can last 25-30 years.

    It also states that solar cells have come a long way in the last 20 years

    I’m hoping this isn’t like tattoo ink where they said. Guaranteed not to fade for 10 years, even though the ink had been around for about 3 years…( that brand )

    Using that logic. If you take care of the solar cells. Wash them, don’t scratch them , don’t let bird poo bake into them , they will probably last 20 years. Wether not they become less efficient over time …. Meh. Who knows

    • Alain Chuzel

      Member
      April 12, 2022 at 1:28 pm

      Solar cell and solar panel (a.k.a. module) are different things. Technically, cells can last a hell of a lot longer than 25-30 years. Top tier solar panels are currently power warranted for 25+ years. It is unlikely Aptera will offer the same kind of warranty because they really can’t assemble and encapsulate them like top tiered solar panels are. It’s the encapsulation that will likely limit their useful life. Yes, take care of them and they’ll likely last well over 10 years though.

      BTW, I’ve been in the solar fab industry for over 30 years. The first Silicon cells I worked with were on the order of 15% efficient at Standard Test Conditions (STC) and made by ARCO Solar. Now the best (Maxeon/SunPower) are, at best, 25.4%. Personally, that seems like NOT such a long way. What has, however, come a long way is the reduced price per watt.

  • Danny Mattijetz

    Member
    April 12, 2022 at 10:24 pm

    You got me thinking, so I decided to do a little search. From the little bit that I read, it would appear that you are right on this point. The quantum amount required to move the electron out of the atom’s orbit and into the conduction band must be met. If the photon had more energy, the difference would go into heat. Many of the photons still pass through the cell and right out the other side. Even solids have a lot of space between atoms.

  • Steven G. Bueche

    Member
    April 13, 2022 at 2:25 am

    I’ll admit that I’m no expert in the field of solar cell study. Having said that, I’d like to ask a question; What are the solar cells covered with and how will the sun effect the longevity of that material before negatively effecting the solar cells production?

    We’ve all had those cheap solar lawn lights with the panels covered in some form of plastic only to have them degrade (fog, blister and turn white) and we’ve had those that were covered in what appears to be glass which seem to last forever.

    Given the material Aptera intends to use, does anyone know of a coating suitable to prevent the epoxy resin (guessing) from this UV break down?

    Could the cells be placed under the read hatch glass as a protective measure? Could the same be made for a roof glass?

    • Alain Chuzel

      Member
      April 13, 2022 at 7:44 am

      Other than the rear hatch solar, if any, it’s still a bit of an unknown on what the top side of the cells will be “covered” with. Given the “composites-based” nature of the car, my bet is it will be a “hard cured resin” of some sort but not likely epoxy-based. I’m personally unaware of any suitably clear UV protection “coatings” that could be applied but I’m reasonably sure they exist.

      With respect to the rear hatch, I’m under the impression that the rear hatch solar cells, if any, will have glass on the top. I’m hoping they will be “bonded” to the rear glass with a, more or less, conventional thermoset-type solar cell encapsulant such as is used for “conventional” glass top solar panels. It is quite likely the rear of these cells will have the identical encapsulant but there will be a need for a reasonably tough “skin” behind that. Overall maintenance for the rear hatch solar would be minimal to 0 if it’s constructed as I laid out.

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