Lithium ion battery charging temperature. The main problems of the experimental results. Proper use of cell phone batteries
In this article, by correct operation of lithium-ion batteries, we will understand compliance with conditions in which lithium-ion ion battery the portable device will be able to operate safely, will last a long time, and the functioning of the device will remain fully functional.
But even if the stress mode was allowed, and the battery became very hot, do not rush to charge it. Wait until it cools down and only then connect it to the charger, then it will be able to accept a charge normally and safely.
During the charging process, the battery should also not overheat; if this happens, it means that too much fluid is flowing through the electrolyte. high currents, and this is harmful.
Low-quality chargers suffer from so-called “fast charging,” like some inductive wireless chargers. It is better not to use such “fast” chargers. The point is that it is safe Charger must respond to the current consumed by the battery during charging and promptly change the supplied voltage, if necessary, reduce it, when necessary, increase it.
If the charger is just a transformer with a rectifier, then your battery will most likely overheat due to overvoltage and gradually break down. Not all fast chargers are compatible with lithium batteries.
Most the best option- an original charger from the same manufacturer as the device being charged, ideally the charger included in the kit. But if it is not possible to use an original charger, then use one that gives a lower current - this will save the battery from overheating due to the supply of excessive power.
A good alternative to the original charger is a computer USB port. USB 2.0 will give 500mA, USB 3.0 - a maximum of 900mA. This is enough for safe charging.
Some of the “fast” devices are capable of pumping 3-4 amperes into the battery, but this is destructive for small-capacity batteries, such as pocket batteries. mobile gadgets(see documentation). A small current from USB is a guarantee of the safety of the lithium-ion battery.
Many devices allow you to remove the battery, so having a spare battery is not a problem at all. The operating time of the device will double, eliminating deep discharge (set in advance backup battery, without waiting full discharge main), there is no temptation to use a harmful “fast” charger. 20% discharge of the main battery is a signal to install a backup one.
If the first battery gets very hot from intense load or due to external heating (accidentally left in the sun), insert a spare one, and while the first one cools down, you will continue to use your device, keeping both batteries unharmed. When the one that has warmed up has cooled down, it can be recharged in the original charger (mains or car).
So, in order for a lithium battery to serve for a long time and faithfully, it is necessary:
1. Do not allow the battery to warm up above 30°C, best temperature 20°C.
2. Avoid overcharging the battery and overvoltage at the terminals, optimally 3.6 V.
3. Avoid deep battery discharge - let 20% be the limit.
4. Avoid high current loads during charging and discharging (see documentation), use USB.
5. Have a backup battery.
Currently, smartphones and tablets use lithium-based batteries and lithium-polymer batteries.
Each of them has its own resource, which depends on the correct charging and operating conditions. There is also the concept of a “charging cycle” - today we will find out what it is.
What is a charging cycle?
The charging cycle is a set of processes associated with filling the battery with energy and completely discharging it. Their number determines how many times the battery can be charged and discharged.
Accurate data on the number of cycles for lithium batteries no, as these figures may vary depending on correct use. On average, the resource of such batteries is 600-800 pieces. This figure may seem small to some, but if we assume daily charging and discharging, then 800 cycles - 800 days, that is, more than two years.
How many charge cycles are left?
Let's imagine a situation that within two days the phone was discharged by 50% both times and mandatory charged up to 100%. In this case, 1 charge cycle was used. Such moments can be repeated regularly, which leads to slower depletion of cycles and extends battery life. For this reason, many experts recommend not waiting for your smartphone to be deeply discharged and charging it regularly.
There is a relationship between the remaining energy in the battery and the number of cycles. Remaining charge level, % - remaining number of cycles:
- 90 - 4700.
- 75 - 2500.
- 50 - 1500.
- 0 - 500.
The table shows that if you discharge your smartphone by 50% every day, the number of charge cycles will be about 1500.
What's the best way to charge your smartphone?
It is important to understand that you cannot keep a fully charged smartphone constantly connected to a charger, for example. No, overcharging will not occur, since the charging controller will stop the flow of current, but a constant drop in the energy reserve to 99% and the subsequent replenishment to 100% will lead to a decrease in the number of charge cycles.
Recharging the battery, which occurs under the control of the user, has proven itself best. As soon as 90-100% is reached, you need to disconnect the gadget from the network. Of course, in Everyday life difficult to provide ideal conditions battery operation, but you must try to follow.
The following factors influence the reduction in the number of possible battery charge cycles and the reduction in its capacity:
- battery overheating;
- regular depletion of charge to 0%;
- using a non-original charger ().
Even if you manage to extend the life of the battery by 2-3 years, the natural aging of its constituent elements will still lead to a decrease in capacity by 15-20%.
With the current growth rate of smartness (SMART) of device controllers, we will soon bow to our battery with a request to give up a little of its energy to operate the device we need so much. And also enter into an agreement on timely feeding of the battery with electricity and make contributions to the social insurance fund for batteries. In addition, the battery will have to pay for health insurance and a share in the pension fund :).
Proper use of cell phone batteries
The electrodes of lithium-ion batteries are already half charged due to the manufacturing process, but it is not advisable to immediately test a fresh battery under load. Initially lithium ion battery needs to be fully charged. Using a battery without an initial charge can dramatically reduce the capacity available to the user.
After initially charging the battery, it is advisable to completely discharge it to calibrate the battery management system. Recharge the battery immediately after discharge. Calibration cycles for cell phones Lithium-ion batteries should not be used frequently (usually one full charge-discharge cycle every 3 months is enough). The calibration cycles themselves are needed only for correct display forecast of remaining battery capacity. The three to four deep charge-discharge cycles recommended by some users and sellers can be fatal for a not new lithium-ion battery.
It is advisable to use original batteries from the manufacturer mobile phone. Since the functions of the battery management system for mobile phones are greatly reduced, and the charge is managed by the cell phone charging system, the battery from third party manufacturer will live less, since the charging system does not know the characteristics of non-original batteries.
Due to the fact that the “aging” effect of lithium-ion batteries increases sharply at high temperatures, it is advisable to keep the cell phone away from heat sources (human body, direct sunlight, heating radiator).
It is advisable not to fully charge the cell phone battery often, and also to charge the battery before the charge level reaches the red level of the charge indicator (approximately 20% of the remaining capacity).
The aging of lithium-cobalt batteries (the most common batteries for cell phones directly depends on the load level). Talk less and less often on your mobile phone - this will keep not only your battery healthy, but also you.
Do not charge a battery that has been in the cold until it warms up to a positive temperature (Celsius) - this important requirement safe operation of lithium-ion batteries.
Correct use of laptop batteries
The laptop battery contains a full-fledged system control, which often allows the user to forget whether he is using the battery correctly. However, there are a few things to keep in mind when working with a laptop.
When connecting for the first time, the laptop battery should be fully charged, and then calibrate the control system. Calibration is carried out by completely discharging the battery under constant load (you must enter BIOS settings, and leave the laptop running when disconnected from the network until shutdown, many BIOS adjusters have a special Calibration item designed to perform this task). Make sure to charge your laptop battery immediately after it is completely drained.
Calibration battery laptop is usually carried out once every 1-3 months, to eliminate the effect of “digital memory” - during operation on battery power, errors in determining the remaining capacity gradually accumulate, which reduces the time battery life laptop.
For some laptop models, there are manufacturer utilities for setting the level of battery discharge at which charging begins. If the laptop battery serves as a source uninterruptible power supply(work is carried out stationary with mains power), then setting the permissible discharge level to 40% and maintaining the battery in a half-discharged state will double the battery life.
Some laptops come with an extra battery. If you do not use it for a long time, it makes sense to discharge extra battery up to 40%, pack in a plastic bag with a vacuum seal and leave the bag in the refrigerator compartment at a temperature of 3-4°C.
Correct use of Power Tools batteries and video cameras
Operating rules batteries Power Tools (mainly screwdriver batteries) and video cameras differ little from the rules for operating cell phone batteries.
The difference is that the use of these devices in everyday life is quite rare, and the cost of batteries is high and these batteries become less accessible over time. To ensure a long life of such batteries, they should be stored in a semi-discharged state in the refrigerator at a temperature of 3-4°C, pre-packed in a plastic bag with a vacuum seal. Before use, the battery must be fully charged using a standard charger, and during operation, the battery must not be completely discharged (at the first opportunity, recharge the battery during operation).
In conclusion of the article, I would like to say that although the operating rules allow you to maintain battery parameters for a long time, life dictates its own operating conditions, which are often incompatible with the concept of proper operation of such a high-tech thing as a lithium-ion battery.
Copyright Dmitry Spitsyn, 2008.
Lithium-ion (Li-ion) batteries are used in most modern tablets, smartphones and laptops, require different rules maintenance and operation compared to nickel-cadmium (Ni-Cd) and nickel-metal hydride (Ni-MH) batteries used in earlier devices.
In fact, proper care Maintenance of a lithium-ion battery can increase its service life by 15 times compared to misuse. In this article we will give tips on how to prolong your life as much as possible. life cycle expensive lithium-ion batteries in all your portable devices.
Just recently, Fred Langa, a journalist for the Internet portal Windows Secrets, had to replace a damaged smartphone - and it was his mistake.
The main symptom did not bode well - the phone case was deformed because the body of the device itself began to bend.
When parsing and detailed consideration It turned out that the smartphone battery was swollen.
Initially, Fred did not notice any changes: the battery looked more or less normal when looking at it face-on (Figure 1). However, when the battery was placed on a flat surface, it became obvious that its top and bottom edges were no longer flat and parallel to each other. There was a serious bulge on one side of the battery (Figure 2). This bulge caused the phone to bend and become deformed.
The battery's bulge indicated a serious problem: the accumulation of toxic gases under high pressure inside the battery.
The battery case did its job perfectly, but the toxic gases made the battery look like a tiny pressure cooker bomb just waiting to detonate.
In Fred's case, both the phone and the battery were damaged - it was time to buy a new smartphone.
The saddest thing is that this problem could have been easily prevented. The final part of the article will highlight Fred's mistakes.
To avoid repeating the mistakes of the past with a new smartphone and others lithium-ion devices, such as tablets, laptops, Fred began to seriously research the proper operation and maintenance of lithium-ion batteries.
Fred wasn't interested in extending battery life - these techniques are familiar. Most devices offer manual or automatic modes Energy saving and techniques for adjusting screen brightness, slowing down processor performance, and reducing the number of applications running.
Fred rather focused on battery life extension issues - ways to keep the battery in good working order. in working condition and extending battery life to the maximum level.
This article includes a brief thesis statement based on Fred's research. Follow these five tips to ensure your lithium-ion batteries perform well, last, and safely in all your portable devices.
Tip 1: Monitor the temperature and do not overheat the battery
Surprisingly, heat is one of the main enemies of lithium-ion batteries. Causes of battery overheating may include misuse factors, such as the speed and duration of the battery's charging and discharging cycles.
The external physical environment also matters. Simply leaving a device with a lithium-ion battery in the sun or in a closed car can significantly reduce the battery's ability to accept and hold a charge.
Ideal temperature conditions for lithium-ion batteries the room temperature is 20 degrees Celsius. If the device heats up to 30C, its ability to carry a charge is reduced by 20 percent. If the device is used at 45C, which is easily achievable in the sun or when the device is intensively used by resource-intensive applications, the battery capacity is reduced by about half.
So, if your device or battery becomes noticeably warm during use, try moving to a cooler location. If this is not possible, try to reduce the amount of power consumed by the device by turning off unnecessary applications, services and features, lowering the screen brightness or activating the device's power saving mode.
If this still doesn't help, turn off the device completely until the temperature returns to normal. For even faster cooling, remove the battery (of course, if the design of the device allows it) - this way the device will cool down faster due to physical separation from the power source.
By the way, despite the fact that high temperatures are the main problem With lithium-ion batteries, low-temperature operating conditions do not cause serious concern. Low temperatures do not cause long-term damage to the battery, although a cold battery will not be able to produce all the power it could potentially produce at its optimal temperature. The drop in power becomes very noticeable at temperatures below 4C. Most consumer-grade lithium-ion batteries essentially become useless at temperatures near or below freezing.
If a device with a lithium-ion power supply becomes excessively cold for any reason, do not attempt to use it. Leave it unplugged and move it to a warm place (pocket or heated room) until the device reaches normal temperature. As with overheating, physically remove the battery and separate heating will speed up the warm-up process. After the battery warms up to normal temperature, its electrolytic properties will be restored.
Tip 2: Unplug the charger to save battery
Recharge - i.e. connecting the battery to the power source for too long high voltage can also reduce the battery's ability to hold a charge, shorten its service life, or what is called “kill it outright.”
Most consumer-grade lithium-ion batteries are designed to operate at a voltage level of 3.6V per cell, but operate at a higher 4.2V when charging. If the charger gives out power for too long increased voltage, the internal battery may be damaged.
In severe cases, overcharging can lead to what engineers call “catastrophic” consequences. Even in moderate cases, the excess heat generated during overcharging will create the negative temperature effect described in the first tip.
High quality chargers can work in concert with the circuitry of modern lithium-ion batteries, reducing the danger of overcharging, reducing charging current proportional to battery charge.
These properties vary significantly depending on the type of technology used in the battery. For example, when using nickel-cadmium (Ni-Cd) and nickel-metal hydride (Ni-MH) batteries, try to leave them connected to the charger for as long as possible. This is because older types of batteries have high level self-discharge, i.e. they begin to lose a significant amount of stored energy immediately after being disconnected from the charger, even if they portable device disabled.
In fact, nickel cadmium battery may lose up to 10 percent of charge in the first 24 hours after charging. After this period of time, the self-discharge curve begins to level off, but the nickel-cadmium battery continues to lose 10-20 percent per month.
The situation with nickel-metal hydride batteries is even worse. Their self-discharge rate is 30 percent higher than that of their nickel-cadmium counterparts.
However, lithium-ion batteries have very low level self-discharge. A good working battery will only lose 5 percent of its charge in the first 24 hours after charging and another 2 percent during the first month after that.
Thus, there is no need to leave the device with a lithium-ion battery connected to the charger until the last moment. For getting best results and extend battery life, disconnect the charger when a full charge is indicated.
New lithium-ion battery devices do not need to be charged extensively before first use (8 to 24 hours of charging is recommended for devices with nickel-cadmium and nickel-metal hydride batteries). Lithium-ion batteries are maximally charged when they indicate 100 percent charge. Extended charging is not necessary.
Not all discharge cycles have the same effect on the condition of the battery. Prolonged and intensive use generates more heat, seriously straining the battery, and shorter, more frequent discharge cycles, on the contrary, extend the battery life.
You might think that increasing small discharge/charge cycles can seriously reduce the life of the power supply. This was only natural for outdated technologies, but does not apply to modern lithium-ion batteries.
Battery specifications can be misleading because... Many manufacturers view the charge cycle as the time required to reach a 100 percent charge level. For example, two charges from 50 to 100 percent are equivalent to one full charge cycle. Likewise, three cycles of 33 percent or 5 cycles of 20 percent are also equivalent to one full cycle.
In short, a large number of small charge-discharge cycles do not reduce the total volume of cycles fully charged lithium battery.
Again, the heat and high load from heavy discharges reduce battery life. So try to reduce the number deep discharges to a minimum. Do not allow the battery charge level to drop to values close to zero (when the device turns itself off). Instead, consider the bottom 15 to 20 percent of your battery charge as an emergency reserve—for emergencies only. Get used to replacing the battery if possible or connecting the device to external source power before the battery is completely discharged.
As you know, fast discharge and fast charging are accompanied by the release of excess heat and negatively affect the battery life.
If you have used the device intensively under high loads, allow the batteries to cool to room temperature before connecting to the charger. The battery will not be able to accept a full charge if it is heated.
While charging the device, monitor the temperature of the battery - it should not overheat too much. A hot battery during charging usually indicates that too much current is flowing quickly.
Overcharging is most likely with cheap unbranded chargers using circuits fast charging or with wireless (inductive) chargers.
A cheap charger can be a regular transformer with wires connected to it. Such “silent charges” simply distribute current and practically do not accept feedback from the device being charged. Overheating and overvoltage are very common when using chargers like this, which slowly destroys the battery.
“Fast” charges are designed to provide a minute charge, not a long hour-long charge. There are different approaches to fast charge technology, and not all of them are compatible with lithium-ion batteries. If the charger and battery are not intended for collaboration, fast charging may cause overvoltage and overheating. Generally speaking, it is better not to use a charger from one brand to charge a portable device from another brand.
Wireless (inductive) chargers use a special charging surface to restore the battery's charge. At first glance, this is very convenient, but the fact is that such charges emit excess heat even in normal mode work (Some cookers use induction to heat pots and pans).
Lithium batteries not only experience a negative factor in the form of heat, but also waste energy during charging. wireless technology. By its nature, the efficiency of an inductive charger is always lower than its conventional counterpart. Here everyone is free to make their own choice, but for Fred, increased heating and lower efficiency are sufficient factors to refuse such devices.
In any case, the safest approach is to use the included charger recommended by the manufacturer. This is the only guaranteed way to keep temperature and voltage within normal limits.
If an OEM charger is not available, use a low output current charger to reduce the chance of battery damage due to high power being applied quickly.
One low current output power source is the USB port on regular computer. Standard port USB 2.0 provides 500mA (0.5A) current per port, while USB 3.0 provides 900mA (0.9A) per port. For comparison, some dedicated chargers can output 3000-4000mA (3-4A). Low current USB port ov in general case guarantee safe charging with normal temperature conditions for most modern lithium-ion batteries.
Tip 5: Use a spare battery if possible
If your device allows for quick battery replacement, having a spare battery is a great insurance policy. This not only doubles the operating time of the device, but also eliminates the need to completely discharge the battery or use a fast charge. When the battery charge reaches 15-20 percent, simply replace the dead battery with a spare one, and you will instantly get a full charge of the device without any overheating problems.
A spare battery has other benefits as well. For example, if you find yourself in a situation where installed battery overheated (for example, due to intense operation of the device or due to high temperature environment), You can change a hot battery to cool it down faster and still continue to use the device.
Having two batteries eliminates the need for fast charging - you can safely use the device while the battery is slowly charging from a safe power source.
Fred's Fatal Mistakes
Fred suggested that he might have damaged his smartphone battery during a road trip. He used GPS function in the device for navigation during a clear sunny day. The smartphone was left in the sun for a long time in a holder in the area dashboard car, the brightness of the smartphone was turned on to maximum in order to distinguish the map among bright sun rays.
In addition, all standard background application - Email, messenger, etc. were launched. The device used a 4G module to download music tracks and wireless module Bluetoorth for transmitting sound to the headset sound device car. The phone was definitely working under stress.
In order for the phone to receive power, it was connected to a 12V adapter, purchased based on the criteria of low price and availability of the correct connector.
Combination of direct sunlight, high load processor enabled on maximum brightness screen and the questionable quality of the adapter led to excessive overheating of the smartphone. Fred remembers with horror how hot the device was when pulled out of the holder. This severe overheating was precisely the catalyst for the death of the battery.
Apparently, the problem got worse at night when Fred left the device plugged in all night using a third-party charger without checking when the battery was fully charged.
With his new smartphone, Fred will only use the included charger and spare battery. Fred hopes for a long and safe life for both the battery and the phone, which he plans to achieve with the help of the tips listed.
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If you are interested in how to charge a lithium-ion battery, then you have come to the right place.
Modern mobile devices require an independent power source.
Moreover, this is true for both “ high technology» like smartphones and , and for more simple devices, say, electric drills or multimeters.
There are many different types of batteries. But for portable equipment Li-Ion is most often used.
The relative ease of production and low cost.
Excellent performance characteristics, plus low self-discharge and a large reserve of charge-discharge cycles, also contributed to this.
Important! For greater convenience, most of these batteries are equipped with a special monitoring device that prevents the charge from crossing critical levels.
When a critical discharge occurs, this circuit simply stops supplying voltage to the device, and when the permissible charge level is exceeded, it turns off the incoming current.
A phone or tablet with a lithium-ion battery should be charged when the battery level is 10–20%.
Moreover, after reaching the nominal 100%, charging should last another one and a half to two hours.
This is necessary because the battery will actually be charged to 70–80%.
Advice! Approximately once every three months it is necessary to carry out preventive discharge.
When charging from a laptop or desktop computer It must be taken into account that the USB port is unable to provide a sufficiently high voltage, therefore, the process will take more time.
Alternating cycles of full and incomplete (80–90%) charging will extend the life of the device.
Despite such a smart architecture and general unpretentiousness, following some rules for using batteries will help extend their life.
To prevent the device’s battery from “suffering”, it is enough to adhere to simple recommendations.
Rule 1. No need to completely discharge the battery
For lithium-ion batteries modern designs there is no “memory effect”. Therefore, it is better to charge them before the moment of complete discharge comes.
Some manufacturers measure the service life of their batteries precisely by the number of charging cycles with zero value.
The highest quality products can withstand up to 600 such cycles. When charging the battery with 10–20% remaining, the number of cycles increases to 1700.
Rule 2. Complete discharge still needs to be done once every three months.
With unstable and irregular charging, the average maximum and minimum charge levels in the previously mentioned controller are lost.
This leads to the device receiving incorrect information about the amount of charge.
Preventive discharge will help prevent this. At complete discharge battery, minimum value charge in the control circuit (controller) will be reset to zero.
After this, you need to charge the battery to capacity, keeping it connected to the network for eight to twelve hours.
This will update the maximum value. After such a cycle, the battery operation will be more stable.
Rule 3: An unused battery should be stored with a small amount of charge.
Before storage, it is better to charge the battery by 30–50% and store it at a temperature of 15 0 C. In such conditions, the battery can be stored for quite a long time without much damage.
A fully charged battery will lose a significant portion of its capacity during storage.
And completely discharged ones after long-term storage will only have to be sent for recycling.
Rule 4. Charging must be done only with original devices
It is noteworthy that the charger itself is built into the design mobile device(, etc.).
External adapter in this case it acts as a rectifier and voltage stabilizer.
Cameras are not equipped similar device. That is why their batteries must be removed and charged during external device.
The use of third-party “charging” can negatively affect their condition.
