The Life of a Smartphone Battery


Exploring Lithium-Ion Batteries:
How they work, Recharge, and Degrade
by: Branch Education It’s crazy every second you use your smartphone,
there’s a chemical reaction, like a baking soda volcano happening inside of it. It looks like a solid device without many moving parts,
but its true! Inside the battery there’s chemical a reaction
that is continuously running and without it, your phone would just be dead,
which is something we’re all familiar with. Let’s investigate this lithium-ion battery.
How does it power your smartphone, what happens when you recharge it,
and probably what we’re all wonder Why does your battery die
earlier and earlier in the day? To answer these questions, let’s
open up this battery and look inside. So first, how does your battery power your smartphone?
Let’s start from what we know. All batteries have a positive terminal
and a negative terminal and supply power or electricity
to our portable devices. So, Electricity is essentially a
flow of electrons and in our smartphone. Electrons which are negatively charged
flow from the negative terminal and run things like the speakers or the display
and then end up at the positive terminal. So then, where does this flow of electrons come from? Well, this is a lithium ion battery,
so the electrons come from the element lithium. At the negative terminal, which is technically called the anode, lithium is stored between layers of carbon graphite,
similar to the graphite in your pencil. Graphite has a nifty crystal structure of layered planes that allows for the lithium to be
wedged in between each of the layers. The technical term for this is intercalation. Graphite functions as kind-of-like a
stable storage space for lithium atoms. Ok- Moving on, one inherent property of the element lithium is that it doesn’t like it’s outer-most electron, and it wants to give it up. When there is an available path from the
negative terminal to the positive terminal, this electron separates from the lithium
and starts heading to the other side. At the same time, the lithium leaves the graphite, and becomes positively or +1 charged and is now called a lithium ion. FYI- an ion is just fancy word for an atom who has lost or gained an electron, and thus is charged. When a lot of lithium atoms leave
the graphite at the same time, a flow of electrons is built up. So, let’s now jump to the positive terminal,
which is technically called the cathode. Here we have Cobalt that has
lost some electrons to oxygen, thus making the Cobalt positive, or +4 charged. As a result, it wants to gain back an electron. So, when we connect the negative
and positive terminals to our smartphone, the electrons flow from the lithium
which wants to give up an electron, through the circuits and components in the smartphone and to the cobalt which wants to gain an electron. Now here we run into a small issue. With the flow of electrons from the
negative to the positive terminal, the cobalt side grows more and more negatively charged, and the other side positively charged. Yes, the electrons do want to flow in this direction, but at the same time electrons don’t like to flow to an area that is growing more and more negatively charged. This is because opposite charges attract,
and similar charges repel. So, to fix this, we give the now
positively charged lithium ions that recently left the graphite,
a path to move to the other side. This path is called an electrolyte,
and its function allows for lithium-ions to migrate over from one side to the other,
while not allowing the electrons to move through it. When lithium gets to the cobalt side, it again wedges itself, or intercalates with the
cobalt and oxygen to become Lithium Cobalt Oxide. The lithium isn’t regaining its electron- that electron went to the cobalt,
it’s just balancing out the charge build up. Let’s quickly recap. Here is a full battery. Throughout the day lithium
atoms leave the graphite layers and separate from their electrons to become lithium ions. The electrons flow from the negative terminal
through the circuits and components in the smartphone and into the positive terminal to join the cobalt atoms. At the same time, the lithium-ions travel through the electrolyte in order to neutralize
the charge build up and keep the reaction going. Here’s the chemical formula for the reaction. Thus, at the end of the day almost
all of the lithium has left the graphite layers, and joined the cobalt to become lithium cobalt oxide,
and your battery is now running on empty. Now that the battery is empty, let’s recharge it. We plug in our smartphone and when we do this the USB charger applies a higher force on a flow of
electrons in the opposite direction. Electrons are pulled out of the cobalt, thus returning cobalt to its +4 state and kicking out the lithium ions. On the other side, electrons are forced onto the graphite, which pulls the lithium through the electrolyte,
and back into the layers of graphite. As you see it’s the exact opposite of the earlier reaction,
which is why this battery is rechargeable. The lithium and its electrons move in one direction
when you use the phone, and the opposite when you charge it back up. Ok, so now let’s rewind and
add a few more details of note. First, these two sides can’t touch,
If the anode and cathode were to touch, and if there were any lithium left in the graphite, the chemical reaction would accelerate uncontrollably
and cause a fire or often a small explosion. Thus, a non-conductive semipermeable separator that allows the lithium-ions to pass through is placed in the middle. And this electrolyte isn’t an effective barrier because it’s a liquid The second thing to note is that the
graphite and cobalt peroxide aren’t good at collecting or distributing the electrons. Thus, a conductive copper layer is added next to the graphite, and a conductive aluminum layer next to the cobalt peroxide. These two layers or sheets are called collectors. Ok, onto third, these animations
are showing 100% of the lithium moving from the anode to the cathode, and back. But in reality, there will always be some percentage of lithium that remains in the anode,
cathode, and electrolyte despite the battery being fully charged or
discharged respectively. Continuing to fourth, in order to
maximize the capacity of the battery, and allow the battery to fit into your smartphone, all these layers are folded and wrapped
into a rectangular prism package. Ugh, I know this is a lot, but fifth and final, in order to regulate the flow of electricity, additional circuitry is added to the top of the battery. This circuitry prevents overcharging
and damage to the battery. So, then the final topic. Why does your battery’s max
capacity reduce over time? There are several reasons, one of which is that sometimes
lithium and the incoming electron react with electrotye and organic solvent to form compounds that are called a
solid electrolyte interphase or SEI SEI’s irreversibly consume lithium and the electrolyte, thus reducing the overall quantity of lithium and thereby reducing the max capacity of your battery. Another reason is that when you
fully discharge your battery until it’s dead, it can result in too much lithium on the cobalt side, which causes the irreversible generation
of Lithium oxide and Cobalt (II) Oxide. These compounds are stuck in that state
which thereby reduces the amount lithium and cobalt for future use. So, one tip is to not let your battery run until its empty. It’s better to recharge your battery at 30 or 40% then to let it run until its dead. That about wraps it up. When it comes to batteries, there are hundreds of different chemistries and
compounds that allow them to work, but they all work on similar principles. You just need three materials, one that wants electrons, one that wants to give up electrons, and then a path for the build up of charge to neutralize. Thanks for watching!
Here are 3 questions I’m going to leave you with. Discuss them in the comments.
Also, ask questions in the comments! If you do it I will pin the top questions for further discussion. Don’t forget to subscribe and tell your friends and family about something you learned today. This episode is about lithium ion smartphone batteries, and it branches to electric vehicle batteries discussed by Learn Engineering,
we recommend you take a look! It also connects to galvanic and voltaic cells, Chemical bonds & electronegativity and lemon batteries. Post your comments with further questions,
answers, and thoughts. And Remember conceptual simplicity
and structural complexity.

100 Replies to “The Life of a Smartphone Battery

  1. Discuss your answers to the 3 questions here: 1) Why Lithium? 2)How can we improve upon the Li-ion battery? 3) What are some far-out dreams for the next evolution in energy storage?

  2. Please make a video on how softwares works in smartphone, how they take commands and how smartphone react to it. Thankyou 👌👍

  3. It only just occurred to me that the anode and cathode of a battery is the opposite of, say, an LED. On a battery, the anode is the negative terminal and the cathode is the positive, whereas on an LED, the anode is the positive terminal and the cathode is the negative. Weird.

  4. in future there will be no batteries instead super capacitors will be used. And we would have to charge our devices only twice a month.

  5. I learn so much about general science/technology information on top of how it is applied to specific applications, love the content.

  6. Very Nice and Informative Video. I loved it and I appreciate your work. Can you please make a video on Fighter Jets Thrusters and Propulsion System and How Thrusters work.

  7. Perhaps if we could find an element that gives up electrons, then another that takes them and somehow they return back to the starting element that would mean infinite flow of electrons. About how doing it, i have thought:1. While lithium ( or a more suitable element) moves to the other side via electrolyte, perhaps we could extract an electron, thus making it even more electron attractive and therefore being able to take back the electron from the cobalt (or a more suitable element). Please i would love to hear any arguments upon this idea…

  8. The weird thing is earlier today I was looking up the ways to make your battery last longer, randomly got a suggestion a few hours later for another one of your videos, looked at the channel uploads and found this. Taking plain text from an article to seeing how the science actually works in detail by the end of the day.

  9. i love your videos, and i wish you make a video about amplitude modulation and demodulation. i'll wait for ya . thanks in avds

  10. What is that grey flap at 7:05 on the top left of the battery? Like an emergency valve for the battery?

    Also, is it an co-incidence that the 3,5-4.2V range of a Lithium-Ion battery is close to the 5V used with USB and how does the 5V from the charger end up to be the correct voltage (eg 3,9V) for the battery?

    Great work on the video, really loved the explanation and the animations

  11. Superb explanation. Now I learned, How our smart phone batteries degraded over time. Thanks a lot making such easily understandable animation video. Respect.

  12. 1) Lithium ranks up higher on periodic table, it's a small atom therefore you can store more of it in same space as other materials on top of the other necessary characteristics.

    2) Solid state is exciting. Teslas dry electrode tech is exciting. Silicon to replace the graphite and Li air batteries I've also heard of but I don't know enough detail.
    As far as better answering the questions I'm really stoked about Teslas dry electrode tech well it still belongs to Maxwell for now. They realized that production processes from capacitor could be applied to Li batteries. The way all the different sheets are bonded is using a wet bonding agent and then the sheets have to be laid out and dried and heated. Using a powdered dry bonding agent once can cut down on manufacturing cost, time and huge amounts of factory floor space. The resulting battery is also a little more energy dense (gravimetrically but probably also to an extent volumetrically) and has quite a bit more power density (20% I believe) because the wet bonding agent remains are restrictive, and being power dense of course will lead to higher charging speeds and higher power output.

    3) I have a far out idea. Not quite energy storage but transmission. There are already solar cells tuned for specific laser frequencies but I wonder if we can have a very powerful laser transmit energy thermally straight into a reactor core to speak. It would have to get through a shielding material inside into some agent like a molten salt type that can absorb the laser and heat up well. It would be super inefficient but the receiver could be very power dense maybe enable electric high performance flight. Okay E storage how about antimatter. We can already make the stuff in small quantities we should figure out to scale that stuff and fly to the stars with massively powerful ion thrusters.

  13. Here in video shown that by using charger electron flows reverse direction so but here by changing not new electron adding???
    If not here no use of extra electricity????
    Please explain….

  14. Wow this excelent work and it must have taken countless hours to make. Are you doing these representations on your own ?

  15. Can u explain why too much of lithium on Cobalt side creates irreversible Li2O & CoO? Also I thought it not seen only consumes max 5% of Li ions, is it true?

  16. It's a good video, but the phone has 1 PROTECTION CIRCUIT IN THE BATTERY, ONE CHARGHING CIRCUIT/PROTECTION/MONITORING CIRCUIT IN THE PHONE, and that circuit is taking care of all and you can discharget to "0%" in witch tha battery has 3.2v left(low) and lower than that will damage the battery. One thing to know is to not keep your phone 100% all day(in the wall). It will damage the battery over time!!!!

  17. I finally well learned how a li-ion battery works! I really appreciate you work, thank you so much!

  18. What if I left my digital camera batteries full power and not using it for six months. Do the batteries got any problem?

  19. Lithium is a highly reactive element and it is in the top of the electrochemical series that's why the lithium is selected as component of the battery..

  20. Is anything in these lithium batteries that can Injure a person if they should leak or if the battery is damaged by heat and they are touching your body in any way??

  21. I guess Cnts & Cubals are future solution.this is my idea about your last Question …for first the answer is:bcuz Li produce the most Voltage.
    for second Qestion:
    the answer is same with the last question but solution for second part of second question maybe can be: collecting old batteries by new batteries not for free,by giving discount to them…maybe we could use them for recycling

  22. Si se cambiara el grafito por otro material con mas capacidad de guardar los iones como el silicio o algun polimero conductor con cadenas

  23. Thank you so much for the video as most of the videos in your channel are what I'm searching for a long time. Keep doing more. Subscribed. 😎

  24. What actually happens when I used my mobile at the time of charging because as charger is connected charging process started at the same time abd I use my mobile so discharging process is also started through the single membrane

  25. That's a great video about batteries! Thanks for making and sharing.

    What's your opinion about cell phone Turbo Chargers? Do they reduce the lifetime of the battery for using higher currents than the normal chargers?

  26. Suuuuuuuuuuuuuuuuuuuuuuuuuppppppppppeeeeeerrrrrrrrrrrrrrr👍👍👍👍👍💪💪💪💪💪👏👏👏👏👏👌👌👌👌👌💐💐💐💐💐💐 thanks

  27. Till now I have never seen such a video on electronics which has a complete knowledge and with full of graphics. I salute to you work. You deserve a millions of subscribers. Thanks a lot guys.

  28. great video! How about using a pop shield/filter in front of your mic? I think even a piece of tissue paper could do.

  29. Your video states the negative terminal is the anode. Incorrect. The positive is the anode, the negative is the cathode. I hope no one writes a summary for others to learn from your details, or they will all look like fools.

  30. Yes I feel good at understanding this concept..but I am not sure about the technical representation of cathode as positive electrode and anode vise versa

  31. Amazing Animation ! Kudos…It made understanding so easy. Must be a lot of effort for you. Thanks for the knowledge shared.

  32. if we found out a solid Electrolayer instead of a liquid one wouldn't it solve a problem of drying overtime? and that will eliminate the problem of lower quality over time.

  33. 1 the ionisation potential of of lithium is low . 2 use of graphene as it provides more room for lithium ions for storage

  34. Ans1)Li has highest electrode reduction EMF ,,
    Ans3)in future , use of nanotechnology in electrolyte to get rid of solid electrolyte interface

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