Need some kind of battery for a project? You can always find a few lithium-ion (LiIon) batteries! They’re in our phones, laptops, and countless other battery-powered things of all shapes and sizes—as hackers, we’ll be working with them more and more. Lithium-ion batteries are second to none when it comes to energy capacity, ease of charging and all the shapes and sizes you can get.
There are also misconceptions about these batteries – bad advice floating around, terrifying videos of devices burning up, and an everyday lack of understanding. Today I’d like to provide a general overview of how to properly treat LiIon batteries to ensure they serve you well in the long run.
Contents
What’s A Battery? A Malleable Pile Of Cells
Lithium-ion batteries are our friends. Now, there can be no real friendship if you two don’t understand each other. The factory that produced them made lithium-ion batteries for human needs. As for us hackers, we’ll want to learn some things.
First thing to learn – one LiIon “unit” is called a cell. The average laptop contains three or six Li-Ion cells, a phone will have one, a tablet will have between one and three. What we call a “battery” is usually one or more cells, along with protective circuits, a case, and a separate connector – usually all three, but not always. A typical voltage is 3.6V or 3.7V, with a maximum voltage of 4.2V – this is chemically defined, the same for most cell types and almost always written on the cell.
In multi-cell batteries, the cells are arranged in a mixture of parallel and series arrangements, called a “configuration”. For example, a typical 6-cell laptop battery might be described as a “3s2p” configuration, meaning “three sections in series, where each section consists of two cells in parallel”. The voltage of such a battery is usually described as one of the battery voltage multiplied by the number of series stages; the 3sXp battery voltage may be labeled as 10.8V, 11.1V or 12.6V.
Parallel cells can be functionally treated as higher capacity cells – for example, if you have two 1000 mAh cells and need a 2000 mAh capacity, you can connect the two cells in parallel and get exactly what you need. Be careful not to connect cells of significantly different capacities – then one of them will receive more charging current than it might need. This arrangement has one problem: if one of the cells fails internally and starts to self-discharge, it causes all other healthy cells connected in parallel to fail. You may have encountered this failure mode if you’ve ever taken apart a dead laptop battery.
Shapes And Sizes, All The Same
There are different physical forms of cells – cylindrical, saccular and prismatic. 18650 is the most popular cylindrical cell format, where 18 indicates the diameter and 65 indicates the length (in millimeters). You will usually see this type of cell in the batteries of laptops and power tools, electric transportation devices of all kinds.
Bag-shaped cells and prismatic cells are usually rectangular, with exceptions such as cylinder-shaped cells in disposable vapes. You’ll see them in phones, thinner laptops, tablets, and generally all kinds of handheld devices. I will refer to the rectangular cells interchangeably as “bag cells”.
You’ll often see the term “LiPo” used online when you’re talking about, for example, helicopter batteries or just some battery bags. LiPo technology is a subset of LiIon technology, usually packaged in pouch cells, and is the same as LiIon for the purposes of this article. LiFePO4 is also a subtype of LiIon, it differs in some important aspects like voltage, but most of this article will still apply.
No matter what type of LiIon cells you use, be it an 18650, some “LiPo” single-cell pack, or a cell in a bag you took out of a dead smartphone, the electronic components required remain largely the same – mainly thanks to the voltages involved being the same. For example, if you have an ESP32 board with a JST-PH 2-pin battery input, it will work whether you have an 18650 in a holder with soldered wires or a cell in a bag that you got from Adafruit. It’s not arcane magic – you just have to follow a few rules. Everything you could ever want to know is here.
Bring Your Multimeter Out
LiIon batteries do not like to be discharged too much; as a general rule, you don’t want to get a LiIon battery below 2.5V – 3.0V, depending on how much current you’re trying to draw at that voltage. Below a certain voltage, LiIon batteries suffer irreversible changes and lose their capacity. 3.0V is my personal threshold, which ensures that my batteries last even longer. No, it’s not a requirement to add an ADC to your load – just make sure your battery has a protection circuit; these are usually set for 2.5V overdischarge protection, and you can get 3.0V ones if you want.
If you discharge slowly, the battery will last longer. This is why your phone’s “0% battery” isn’t the actual 0% battery capacity – there’s usually some power left, but using it would compromise battery capacity in the long run. This is also why some laptops have an 80% battery charge level limit available to the BIOS to extend the pack’s life expectancy – you trade some operating capacity for this, but it’s worth thinking about.
LiIon batteries want to be properly charged. You’ll see CC/CV mentioned – this refers to “constant current/constant voltage”, where first the battery is fed constant current with the cell increasing its voltage as it charges, and when its voltage reaches some threshold, the charging mode switches to keep the charging voltage somewhat constant and instead reduce the current over time. This two-stage charging process requires charging ICs – luckily, they’re ubiquitous. If you have a device that accepts a LiIon battery, it probably has a built-in charger; for your own devices chargers are easy to find as modules.
When working with small cells under 1000mAh, you’ll want to make sure your charge current is half the battery capacity number, or even less – so for a 1000mAh cell, that would be 0.5A or less. For example, the ever-present TP4056 modules are set for a current of 1 A. Let’s say you tried to charge a 100 mAh battery with it – this is one of the rare cases where the cell might be violently unhappy with your treatment. Fortunately, for the blue “TP4056” modules, replacing the resistor is all that is required – and TP4056 boards often include a protection circuit!
Protection And Monitoring
Remember – LiIon cells can put a lot of current into anything you connect to their terminals. When working with unprotected cells, it is important not to accidentally short them. For example, if you want to repair a powerbank, first unsolder the negative terminal – just like with car batteries. This will reduce the chances of soldering the positive pin to ground – this would break the protective circuit, cause a small spark, and the battery could lose some of its capacity. This is one more reason why you have a protection circuit – they trip in cases of overcurrent.
To summarize: with a single-cell (or single-stage) battery, you’ll need a protection circuit, and a charger will be somewhere in the picture. For LiIon packs where multiple cells are connected in series, you’ll need a protection circuit wired into the connections between the cells, to properly monitor overdischarge – and you’ll also want some form of balancing wired into them, ensuring that individual parts of the battery don’t overcharge. This combination of protection and balancing circuits is often referred to as a “BMS” (Battery Management System).
If you end up with a lot of unused batteries or cells lying around, there is something you could improve. It has been found that you should not store your batteries at 100% charge for long periods of time as this could cause capacity loss – 50-60% charge is a better storage level. So if you want to put your cells on the shelf for a few months or more, it’s best to set them to 3.8V-3.6V first. Not that a fully charged storage will kill your battery – I can’t deny, I store most of my cells fully charged and this has not been a problem so far. This is a much bigger concern for LiPo pouches than LiIon cells.
Mechanical Manipulations
If you ever need to use blunt force to remove a stuck cell, use blunt plastic tools instead of metal ones – and try to find a different way first. Let’s say you want to free the sac cell from an old tablet. First, try injecting copious amounts of isopropyl under the battery and letting it soften, and twist the cell instead of bending it – you might find you don’t need any tools at all. If you still need to pierce the cell with something, use a cut up old credit card. Heat (ie hair dryer) is generally not recommended.
One thing I highly recommend you avoid is puncturing the inflated bag cell. Of course, sometimes accidental drilling happens when restoring things and you’ll be fine if you get out of your cell for a bit, but don’t go around punching holes in spiced pillows for fun.
For 18650 (cylindrical) cells, they are harder to drill, but still possible. One of these cases is disassembling a laptop battery, cutting the plastic of the battery case with sharp metal tools – be careful! The housing is the negative terminal, so if you cut the shrink wrap, do not make contact with the positive tip. However, if your 18650 plastic cover is missing or torn, that’s fine – it’s just a special type of thermocouple you can buy cheap and put on the hot air cell.
If you want to use 18650s in your creations, it’s best to stock up on the holders or print them out. The next best thing is to spot weld metal strips to them – some shops will do this for you – and solder the wires to them. Soldering directly to 18650 cells is a tricky subject. The consensus is that it can be done, but it’s best not to.
Applying heat to the body of an 18650 cell is best done in small amounts – as such, using a higher powered soldering iron for a short period of time is probably the safest way to go about it. Maybe one of your friends or a nearby hackerspace has a spot welder you can use instead – or can you make your own?
Long-term storage of cells and batteries is not rocket science – a free shelf is sufficient. Make sure that they are not mechanically compromised, i.e. that they will not fall, there is nothing heavy/sharp on them, blah blah. For bagged cells without protective circuits, you should wrap the exposed terminals in something like kapton tape while they are being stored and put them in a fire-safe location just in case. For 18650s, there are cheap plastic cases you can store them in. Ammo boxes might be tempting, but be careful that the metal doesn’t fuse the cells as they rattle around inside.
Be Picky When Making Friends
As hackers, we can get LiIon cells from countless different sources. This is wonderful, as our projects come in all shapes and sizes – some will be fine with an 18650, some can be powered by a smartphone battery or a flat cell cleaned by an ultrabook, some are small enough that maybe a vape battery will be better . to bet.
However, not all of these cells will be good for you – there are some simple indicators that a cell is worse and may be damaged internally, and you should be on the lookout for these signs. I’ll give you an acronym – L.U.S.H., which stands for “Lacerated, Undervolted, Subpar, Heated”.
Is the silver lining of your bag cut? Is your 18650 dented on the side? Did you mishandle your RC car LiPo pack and now it’s squashed like before? If so, recycle it rather than reuse it. It’s okay to have a bit of a dent on the negative terminal of your 18650 as you use the sheet metal snips to get rid of the leftover spot weld tape. In addition, there is usually not much mechanical space between the cell’s sidewall and its inner electrode layers, and pinching these layers together is a possible point of failure.
If the cell is lower than 2.5V, put it in the container. In case your cell has a protection circuit and the output of that circuit is at 0V, you may want to measure before the protection circuit, directly at the cell contacts – usually by gently cutting Kapton or plastic tape where necessary, perhaps using the sewing needles of your multimeter probe . Again, if it’s below 2.5V, bin it – and consider keeping the protection circuit, it might prove useful later! Also, be sensible – if you disassembled the laptop battery, where two parts are 3.5 V and one is 3 V, you better throw the latter in the bin.
Loss of capacity means the cell is damaged, and you don’t want to use a damaged LiIon cell. For example, laptop battery manufacturers use indicators of cell damage (overdischarge, overcharge, and overheating) as a trigger to shut down the battery controller and block the entire battery – and it makes sense, because they don’t want to be held responsible. Even then, an overall severe loss of capacity is not usually considered a trigger for such protection. Also – if the battery has sub-par capacity for its size or rating, throw it in the trash.
When charging the battery for the first time after being freed from the previous host, make sure it doesn’t get noticeably hot – if it does, throw it in the trash. After charging, measure the voltage and write it down. It will gradually decrease after you stop charging, but it shouldn’t drop too much. If it drops more than 0.3V from where it was after you stopped charging, or just drops and drops during the week, trash it – high levels of self-discharge usually go hand in hand with loss of capacity.
Wait, What About Those Fires?
Fire risks with LiIon batteries in typical hacking cases are negligible. After all, we usually have thousands of LiIon cells in our general vicinity – consider all the phones, laptops, electric cars and the like, and they work wonders over thousands of cycles over the long term. Typical LiIon fires occur due to mechanical damage to the cell, serious neglect of electrical requirements, and rarely due to faulty manufacturing. Once you’ve learned how to treat your cells well and dispose of them when necessary, you’re well equipped to avoid battery fires. Want to learn more about LiIon battery fire safety? Our colleague talked about it in more detail.
When you need to dispose of a used or degraded LiIon battery, are you understandably worried that its terminals will short out or the cell will puncture after you throw it in the trash? Good news – a completely discharged battery is completely safe from any accidents, there is no more internal energy to burn.
How to completely empty the cell? First, you can short the cell terminals with something like a 10K hole resistor and let it discharge completely. Be careful to connect to the cell and not to the output of the protection circuit! Another way I’ve seen people do it is to put the cell (or the whole pack) in salt water and keep it there for a while – preferably outdoors in an open container. This might sound a little wacky, but scientific research abounds! [Editor’s Note: Sounds wacky! I only use a resistor.]
Go On, LiIon!
We have not always been well equipped to handle LiIon batteries. Back in the day, cheap tank devices used two diodes from the 5V input to “charge” the battery – resulting in bloated and unhappy bags. Today, you’ll see hackers and makers outfitting their devices with LiIon batteries left and right, shields and chargers are ever-present, and skills should be ubiquitous as well. Never stop learning and you’ll always be equipped to make your projects more portable, error-proof, and reliable.
Next time I’d like to talk about specifics – I want to give you a hacker-friendly cookbook with examples of LiIon battery electronics that are easy to replicate at home. Until then – solder a JST-PH cable to your smartphone cell and plug it into the ESP32 board you bought, see what it does!
Are lithium-ion batteries hazardous?
Lithium batteries are generally safe and unlikely to fail, but only as long as there are no failures and the batteries are not damaged. When lithium batteries are not working safely or are damaged, they can pose a fire and/or explosion hazard.
What is the hazard class of lithium-ion batteries? Lithium-ion and lithium-metal cells and batteries are listed as Class 9 Miscellaneous Hazardous Materials in the U.S. and International Hazardous Materials (Dangerous Goods) Regulations and are subject to special packaging, labeling, labeling, and shipping paper requirements.
Are lithium batteries hazardous to your health?
⺠Exposure to lithium can cause loss of appetite, nausea, vomiting, diarrhea, and abdominal pain. ⺠Lithium can cause headache, muscle weakness, twitching, blurred vision, loss of coordination, tremors, confusion, seizures and coma.
Do lithium batteries give off radiation?
Do lithium-ion batteries emit radiation? No, similar to alkaline batteries, lithium-ion batteries are simply a storehouse of chemical energy, which without a complete circuit does not provide electricity and does not emit any radiation.
Are lithium batteries carcinogenic?
Some possible lithium-ion battery materials are toxic, carcinogenic, or may undergo chemical reactions that produce dangerous heat or gases. Toxic materials include lithium compounds, nickel compounds, arsenic compounds, and dimethoxyethane.
Are Duracell batteries alkaline or lithium?
Today, Duracell produces two alkaline batteries: Optimum and Coppertop.
What type of Duracell battery is it? Duracell makes alkaline batteries in many common sizes, such as AAA, AA, C, D and 9V.
Which batteries are alkaline?
Alkaline batteries are most commonly available as:
- D cells.
- C cells.
- AA cells.
- AAA cells.
- AAAA cells.
- N cells.
- 9V cells.
- Button cells.
How do you know if batteries are alkaline?
ï¨ Alkaline batteries are identified by the words âAlkalineâ or the letters âALKâ ï¨ All types of alkaline batteries can be stored in the same container ï¨ Terminals on AAA, AA, C and D-cell batteries do not need to be taped.
What brand of batteries are alkaline?
The US alkaline battery market is highly concentrated between a few key brands including Duracell, Energizer, Rayovac and private label offerings. Among batteries purchased online, Amazon Basics accounted for 31 percent of the market share, making it the best-selling battery brand online.
Are all AA batteries alkaline?
AA Battery Capacity (mAh) Fortunately, the most common types of batteries are alkaline (primary, non-rechargeable) and nickel metal hydride (NiMH, secondary, rechargeable) batteries, but lithium AA batteries are gaining ground.
Are all Duracell batteries alkaline?
| Brand | Duracell |
|---|---|
| Battery composition | Alkaline |
| Recommended use of the product | Remote controls |
| Number of units | 40.0 No |
| voltage | 9 volts |
What brand of batteries are alkaline?
The US alkaline battery market is highly concentrated between a few key brands including Duracell, Energizer, Rayovac and private label offerings. Among batteries purchased online, Amazon Basics accounted for 31 percent of the market share, making it the best-selling battery brand online.
What is the difference between alkaline and Duracell batteries?
Review below. The main difference between a zinc battery and an alkaline battery is the type of electrolyte used in both batteries. Zinc batteries mainly consist of ammonium chloride, while alkaline batteries use potassium hydroxide.
How do you know if a battery is alkaline?
On a typical alkaline AA battery, the flat side is usually the positive side. A small circular protrusion should be visible on the opposite side. The side is usually the negative end.
Are Duracell lithium batteries?
Duracell High Power Lithium batteries have a guaranteed shelf life of up to 10 years so you can be sure these batteries will be ready when you need them. Long lasting power, guaranteed.
What brand of batteries are lithium?
China-based CATL was the leading producer of lithium-ion batteries in 2021 with a market share of 32.5 percent. Second is Korea’s LG Chem with a market share of 21.5 percent, followed by Panasonic with a market share of 14.7 percent.
Are Duracell batteries allowed on planes?
Batteries allowed in carry-on baggage include: ⢠Alkaline dry cell batteries: typical AA, AAA, C, D, 9-volt, button size cells, etc. consumer size lithium ion batteries (up to 100 watt hours per battery).
What items have lithium batteries?
Lithium-ion batteries are rechargeable and are used in vaping devices, many personal electronics such as mobile phones, tablets and laptops, e-bikes, electric toothbrushes, tools, hoverboards, scooters and for solar backup storage.
How do I know if my device has a lithium battery?
Do cell phone have lithium batteries?
Cell phones contain a rechargeable lithium-ion (or lithium-ion) battery. Li-ion batteries charge faster than traditional rechargeable batteries. That’s why you can connect your iPhone or Android phone to the charger, and its acceleration to at least 80% charge happens quite quickly.
Can I take a lithium battery on the plane? Spare (non-installed) lithium metal batteries and lithium ion batteries, electronic cigarettes and vaping devices are prohibited in checked baggage. They must be carried with the passenger in hand luggage.
Do phones have lithium?
Although not the lightest, lithium-ion batteries are generally much lighter than most battery types of the same capacity. Mobile device manufacturers prefer them because they make smartphones very light. The electrodes of Li-Ion batteries are made of light lithium and carbon, which makes the batteries very light.
Do phones contain lithium?
Lithium-ion (Li-ion) battery technology has historically been the power cell of choice for smartphones and a wide range of other portable devices. However, modern smartphones now typically have lithium-polymer (Li-poly) batteries, a suitable alternative for a wide variety of consumer electronics.
Which phone has lithium battery?
Most smartphone brands, including Samsung, iPhone, Infinix, Nokia, use lithium-ion batteries.
Does iPhone use lithium?
Apple lithium-ion batteries They’re in every iPhone, iPad, iPod, Apple Watch, MacBook, and AirPods, helping you do a variety of things in all kinds of places.
Which phone has lithium battery?
Most smartphone brands, including Samsung, iPhone, Infinix, Nokia, use lithium-ion batteries.
Does Samsung phone have lithium battery?
Every Samsung mobile device is equipped with a lithium-ion battery to enhance your Galaxy experience.
Do phones still have lithium batteries?
Lithium-ion (Li-ion) batteries are used in most of our modern smartphones. These batteries consist of three different parts, an anode (negative terminal) made of lithium metal, a cathode (positive terminal) made of graphite and an electrolyte separator between them to prevent a short circuit.
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