The operating time of modern smartphones without recharging is determined by their battery and its characteristics.
What are batteries?
Nickel-cadmium (Ni-Cd) and nickel-metal hydride (Ni-MH) batteries are no longer relevant - they worked properly for a long time, but had a number of drawbacks. In our gadgets, in most cases, lithium-based batteries are used - lithium-ion (Li-Ion) and lithium-polymer (Li-Pol).
One of the main characteristics of a battery is its capacity. It determines how much electricity the battery can store and how long the device can work autonomously. The most commonly used batteries are 2000 to 3000 mAh (milliamp/hour). The dimensions of lithium-ion sources remain very compact, unlike their predecessors.
Lithium-polymer batteries differ from lithium-ion batteries in a variety of geometric shapes and, which is especially important now, in a minimum thickness that starts from 1 mm. This allows them to be used in very thin smartphones.
Lithium batteries have a long service life if used properly. Manufacturers of many well-known smartphones have provided for the replacement of the battery only at the service center, making the body of the device monolithic, and the back cover and battery are non-removable. Without special equipment and knowledge, the user himself will not be able to carry out this operation.
temperature during operation. The battery capacity is directly affected. A high temperature contributes to a faster accumulation of energy, at a low temperature the capacity drops significantly. If you use an insufficiently charged one, it will quickly discharge. Moreover, there is a risk of lowering the charge to zero, which is highly undesirable - lithium batteries suffer from a complete discharge.
And the opposite situation. A 100% charged smartphone is used in direct sunlight. Figuratively speaking, in this case, 100% of the charge turns into 110%, and an excess of accumulated electricity is obtained, which can lead to a decrease in capacity.
Based on this, it is worth observing the temperature conditions for the operation of the gadget. Moreover, we are not talking about natural heating during active use - such an increase in temperature for the battery is not dangerous
Charging time and charger. Each lithium source is equipped with a special controller, which should protect it from excess current. When a full charge is reached, the incoming current is turned off.
In the operation of the controller, errors and errors are possible that lead to overcharging. Sometimes this is due to the use of non-original smartphone chargers. It is not recommended to leave a charging smartphone in the outlet for a long time after it reaches a full charge. You also need to use original chargers or those whose parameters are .
Lithium batteries need to be charged without waiting for the device to turn off completely, for example, by 10-15% of the residual charge. They can be powered whenever possible during the day, for example, from the USB port of a work computer or in a car. Achieving a full charge is not necessary.
Storage. If the smartphone owner plans not to use the device for a long time, the recommended battery charge level in this case should be about 50%.
The number of charge cycles for lithium batteries is approximately 1200 times. Simple arithmetic suggests that the battery life will last at least 3 years. If you follow the recommendations above, you can increase battery life.
Which is widely used in modern consumer electronics and finds its application as an energy source in electric vehicles and energy storage devices in energy systems. It is the most popular type of battery in devices such as cell phones, laptops, electric vehicles, digital cameras and camcorders. The first lithium-ion battery was released by Sony Corporation in 1991.
Characteristics
Depending on the electro-chemical circuit, lithium-ion batteries show the following characteristics:
- The voltage of a single cell is 3.6 V.
- Maximum voltage 4.2 V, minimum 2.5-3.0 V. Chargers support voltage in the range 4.05-4.2 V
- Energy density : 110 … 230 W*h/kg
- Internal resistance : 5 … 15 mOhm/1Ah
- The number of charge / discharge cycles before the loss of 20% capacity: 1000-5000
- Quick charge time: 15 min - 1 hour
- Self-discharge at room temperature: 3% per month
- Load current relative to capacitance (C):
- constant - up to 65C, pulsed - up to 500C
- the most acceptable: up to 1C
- Operating temperature range: -0 ... +60 °C (batteries cannot be charged at low temperatures)
Device
A lithium-ion battery consists of electrodes (cathode material on aluminum foil and anode material on copper foil) separated by electrolyte-impregnated porous separators. The package of electrodes is placed in a sealed case, the cathodes and anodes are connected to the current collector terminals. The body has a safety valve that relieves internal pressure in emergency situations and violation of operating conditions. Lithium-ion batteries differ in the type of cathode material used. The current carrier in a lithium-ion battery is a positively charged lithium ion, which has the ability to intercalate (intercalate) into the crystal lattice of other materials (for example, into graphite, metal oxides and salts) with the formation of a chemical bond, for example: into graphite with the formation of LiC6, oxides (LiMO 2) and salts (LiM R O N) of metals. Initially, metallic lithium was used as negative plates, then coal coke. Later, graphite began to be used. Until recently, lithium oxides with cobalt or manganese were used as positive plates, but they are increasingly being replaced by lithium ferrophosphate, which turned out to be safe, cheap and non-toxic and can be disposed of in an environmentally friendly manner. Lithium-ion batteries are used in a set with a monitoring and control system - SKU or BMS (battery management system) and a special charge / discharge device. At present, three classes of cathode materials are used in the mass production of lithium-ion batteries: - lithium cobaltate LiCoO 2 and solid solutions based on isostructural lithium nickelate - lithium manganese spinel LiMn 2 O 4 - lithium ferrophosphate LiFePO 4 . Electrochemical circuits of lithium-ion batteries: lithium-cobalt LiCoO2 + 6xC → Li1-xCoO2 + xLi+C6 lithium-ferrophosphate LiFePO4 + 6xC → Li1-xFePO4 + xLi+C6
Due to low self-discharge and a large number of charge-discharge cycles, Li-ion batteries are most preferred for use in alternative energy. Moreover, in addition to the BMS system (SKU), they are equipped with inverters (voltage converters).
Advantages
- High energy density.
- Low self-discharge.
- No memory effect.
- Maintenance free.
Flaws
The first generation Li-ion batteries were subject to an explosive effect. This was explained by the fact that they used an anode made of metallic lithium, on which, during multiple charge/discharge cycles, spatial formations (dendrites) appeared, leading to the short circuit of the electrodes and, as a result, fire or explosion. This problem was finally solved by replacing the anode material with graphite. Similar processes also occurred on the cathodes of lithium-ion batteries based on cobalt oxide when operating conditions were violated (recharged). Lithium-ferro-phosphate batteries are completely devoid of these shortcomings. In addition, all modern lithium-ion batteries are equipped with a built-in electronic circuit that prevents overcharging and overheating due to overcharging.
Li-ion batteries with uncontrolled discharge may have a shorter life cycle compared to other types of batteries. When fully discharged, lithium-ion batteries lose the ability to charge when the charging voltage is connected. This problem can be solved by applying a higher voltage pulse, but this negatively affects the further characteristics of lithium-ion batteries. The maximum "life" of a Li-ion battery is achieved when the charge is limited from above at the level of 95% and the discharge is 15–20%. This mode of operation is supported by the BMS monitoring and control system (SKU), which is included with any lithium-ion battery.
Optimal storage conditions for Li-ion batteries are achieved when charged at a level of 40-70% of the battery capacity and at a temperature of about 5 °C. At the same time, low temperature is a more important factor for small capacity losses during long-term storage. The average shelf life (service life) of a lithium-ion battery is 36 months on average, although it can vary from 24 to 60 months.
Loss of storage capacity :
| temperature | with 40% charge | with 100% charge |
|---|---|---|
| 0⁰C | 2% per year | 6% per year |
| 25⁰C | 4% per year | 20% per year |
| 40⁰C | 15% per year | 35% per year |
| 60⁰C | 25% per year | 40% for three months |
According to all current regulations for the storage and operation of lithium-ion batteries, to ensure long-term storage, it is necessary to recharge them to a level of 70% capacity once every 6–9 months.
see also
Notes
Literature
- Khrustalev D. A. Accumulators. M: Emerald, 2003.
- Yuri Filippovsky Mobile food. Part 2. (RU). ComputerraLab (May 26, 2009). - Detailed article about Li-ion batteries. Retrieved May 26, 2009.
Links
- GOST 15596-82 Terms and definitions.
- GOST 61960-2007 Lithium batteries and rechargeable batteries
- Lithium-ion and lithium-polymer batteries. iXBT (2001)
- Lithium-ion batteries of domestic production
| Galvanic cell | Galvanic Daniel cell | Alkaline element | | Dry element | Concentration element | Air-zinc element | Normal Weston element |
|---|---|
| Electric batteries | Lead Acid | Silver-zinc | Nickel Cadmium | Nickel Metal Hydride | Nickel-zinc battery | Li-ion | Lithium Polymer | Lithium Iron Sulfide | Lithium Iron Phosphate | Lithium Titanate | Vanadium | Iron-nickel |
| fuel cells | Direct methanol | Solid oxide | Alkaline |
| Models | Battery | Electric battery | fuel cell |
| Device | |
Different subspecies of the lithium-ion electrochemical system are named according to the type of their active substance, and can be denoted both in full by words, and in a shortened form - by chemical formulas. What unites lithium batteries is what they all refer to sealed maintenance-free batteries. Such formulas are not very convenient for reading or memorizing due to their complexity, therefore they are also simplified - to a letter abbreviation.
For example, lithium cobaltite, one of the most common materials for lithium-ion batteries, has the chemical formula LiCoO2 and the abbreviation LCO. For reasons of simplicity, the short verbal form "lithium cobalt" may also be used. Cobalt is the main active substance and it is on it that the type of battery is characterized. Other types of lithium-ion electrochemical system are also similarly reduced to a short form. This section lists the six most common types of Li-ion.
1. Lithium cobalt battery (LiCoO2)
The high energy density makes the lithium cobalt battery a popular choice for mobile phones, laptops and digital cameras. The battery consists of a graphite anode and a cobalt oxide cathode. The cathode has a layered structure, and during the discharge, lithium ions move towards it from the anode. When charging, the direction is reversed. The disadvantage of lithium-cobalt batteries is a relatively short service life, low thermal stability and limited load capacity (power density). Figure 1 shows the structure of such a battery.
Figure 1: The structure of a lithium-cobalt battery. During discharge, lithium ions move from the anode to the cathode, while charging - from the cathode to the anode.
Lithium-cobalt battery cannot be charged or discharged at a current higher than its C-rated. This means that a 2400 mAh 18650 cell can be charged or discharged with a current not exceeding 2400 mA. Forcing a fast charge or connecting a load requiring more than 2400 mA will result in excessive stress and overheating. For fast charging, manufacturers recommend a C-rating of 0.8C or about 2000 mA. When using the battery protection system, it automatically limits the charge and discharge to a safe level - about 1C.
Figure 2: Evaluation of an average lithium-cobalt battery. The lithium-cobalt electrochemical system stands out for its high energy density, but offers average power density, safety and service life.
Characteristic table
| Lithium cobaltite: LiCoO2 cathode (~60% cobalt), graphite anode Abbreviation: LCO or Li-cobalt Designed in 1991 |
|
| Voltage | 3.60 V nominal; standard operating range - 3.0-4.2 V |
| Specific energy intensity | 150-200 W*h/kg; specialized models provide up to 240 Wh/kg |
| C-rated charging | 0.7-1C, charging voltage 4.20V (most models); the charging process usually takes 3 hours; Charging current greater than 1C shortens battery life |
| C-rating rank | 1C; at a voltage below 2.50 V, the cutter is activated; discharging current above 1C shortens battery life |
| 500-1000, depending on the depth of discharges, load, temperatures | |
| thermal breakdown | Usually at 150°C. Full charge promotes thermal runaway |
| Areas of use | Mobile phones, tablets, laptops, cameras |
| Comment | Very high specific energy intensity, limited specific power. The high cost of cobalt. Serves in areas where high capacity is required. Has a stable demand in the market. |
Table 3: Lithium cobalt battery specifications.
2. Lithium manganese battery (LiMn2O4)
The design of a lithium-ion battery with manganese spinel was first published in the Materials Research Bulletin in 1983. In 1996, Moli Energy commercialized a lithium ion cell with lithium manganese spinel as the cathode material. The three-dimensional structure of the spinel improves the flow of ions at the electrode, resulting in a reduction in internal resistance and improved current handling. Another advantage of spinel is its high thermal stability, but life and number of cycles are limited.
The low internal resistance of such a cell ensures fast charging and a high possible discharge current. In the 18650 size, a lithium manganese battery can be discharged with a current of 20-30 A with moderate heat generation. In addition, it is able to withstand impulses up to 50 A for one to two seconds. A continuous load of 50 A will lead to heating of the battery, which should not exceed 80 ° C to avoid degradation. Lithium-manganese batteries are used for powerful tools, medical equipment, as well as in hybrid and electric vehicles.
Figure 4 is a graphical illustration of a three-dimensional crystal frame of the cathode material. This material is spinel, in which the initial diamond-shaped lattice structure is transformed into a three-dimensional one.
Figure 4: Structure of a lithium-manganese battery. The crystalline lithium-manganese spinel cathode has a three-dimensional skeletal structure that appears after the initial formation. Spinel provides low resistance but has a more moderate energy density than cobalt.
The capacity of a lithium-manganese battery is about a third less than that of a lithium-cobalt battery. Design flexibility allows you to optimize the battery for different tasks and create models with improved durability, power density or energy density. For example, the 18650 version with improved power ratings has a capacity of only 1100 mAh, while the capacity-optimized version has 1500 mAh.
Figure 5 shows a hexagonal plot of a typical lithium manganese battery. The performance may not seem particularly impressive, but the latest developments have improved performance in terms of power density, safety and life expectancy.
Figure 5: Characteristics of a conventional lithium manganese battery. Despite moderate overall performance, the new models show improved power density, safety and lifespan.
Most Lithium Manganese batteries are combined with Lithium Nickel Manganese Cobalt (NMC) batteries to increase energy density and extend battery life. This union takes advantage of the strengths of both systems and is called the LMO (NMC). It is these combination batteries that are used in most electric vehicles such as the Nissan Leaf, Chevy Volt and BMW i3. LMO is a part of such a battery, which is about 30%, provides high accelerating capabilities of the electric motor, and the NMC part is responsible for the size of the autonomous run.
Research in the lithium-ion system has largely gravitated toward combining lithium-manganese cells with nickel-manganese-cobalt cells. These three active metals can be easily combined to achieve the desired result, whether it is an increase in power density, load characteristics or battery life. This wide range of capabilities is needed to meet the single technology approach and the consumer battery market, where capacity comes first; and industries that require battery systems with good load characteristics, long service life and reliable safe operation.
Characteristic table
| Lithium manganese spinel: LiMn2O4 cathode, graphite anode Abbreviation: LNO or Li-manganese (spinel structure) Designed in 1996 |
|
| Voltage | 3.70 V (3.80 V) nominal; standard operating range - 3.0-4.2 V |
| Specific energy intensity | 100-150 W*h/kg |
| C-rated charging | Standard 0.7-1C; 3C maximum; charging up to 4.20V (most batteries) |
| C-rating rank | Standard 1C; there are models with 10C; pulse operation mode (up to 5 seconds) - 50С; at 2.50 V, the cutoff is activated |
| Number of charge/discharge cycles | 300-700 (depending on the depth of discharges and temperature) |
| thermal breakdown | Usually at 250°C. Full charge promotes thermal runaway |
| Areas of use | Power tools, medical equipment, electrical power units |
| Comment | High power but moderate capacity; safer than lithium-cobalt; usually used in conjunction with NMC |
Table 6: Characteristics of the lithium-manganese battery.
3. Lithium nickel manganese cobalt oxide battery (LiNiMnCoO2 or NMC)
One of the most successful implementations of the lithium-ion electrochemical system is the combination of nickel, manganese and cobalt (NMC) in the cathode. Similar to lithium-manganese systems, these systems can be optimized for capacity or power. For example, an NMC battery in a medium duty 18650 cell has a capacity of 2800mAh and can deliver 4-5A of current; and the version in the same size, but optimized for power performance, has a capacity of only 2000 mAh, but its maximum discharge current is 20 A. The capacity indicator can be increased up to 4000 mAh if silicon is added to the anode. But on the other hand, this will significantly reduce the load characteristics and durability of such a battery. Such ambiguous properties of silicon appear due to its expansion and reduction during charging and discharging, which leads to mechanical instability of the battery design.
The secret of NMC technology lies in the combination of nickel and manganese. Ordinary table salt can serve as an analogy, where separately its components, sodium and chlorine, are very toxic, but their combination forms a useful food substance. Nickel is known for its high energy density but low stability; manganese, on the other hand, has the advantage of a spinel structure, which provides low internal resistance, but also leads to the disadvantage of low specific energy intensity. The combination of these metals allows you to compensate for the shortcomings of each other and make full use of the strengths.
NMC batteries are used for power tools, electric bikes and other powertrains. The composition of the cathode, as a rule, combines nickel, manganese and cobalt in equal parts, that is, each metal occupies a third of the total volume. This distribution is also known as 1-1-1. The combination in this ratio is advantageous for its cost, since the content of expensive cobalt is relatively small compared to other versions of the battery. Another successful NMC combination contains 5 parts nickel, 3 parts cobalt and 2 parts manganese. Experiments to find successful combinations of these active substances are still ongoing. Figure 7 shows the characteristics of the NMC battery.
Figure 7: Evaluation of NMC battery characteristics. NMC has good overall performance and excellent energy density. This battery is the preferred choice for electric vehicles and has the lowest self-heating rate.
Recently, it is the NMC family of lithium-ion batteries that has become the most popular, since thanks to the possibility of combining active substances, it has become possible to design an economical battery with good performance. Nickel, manganese and cobalt can be easily blended to meet a wide range of requirements for electric vehicles or energy storage systems that require regular cycling. The NMC battery family is actively developing in its diversity.
Characteristic table
| Lithium nickel manganese cobalt oxide: LiNiMnCoO2 cathode, graphite anode Abbreviation: NMC (NCM, CMN, CNM, MNC, MCN similar to metal combination) Designed in 2008 |
|
| Voltage | 3.60-3.70 V nominal; standard operating range - 3.0-4.2 V per cell, or higher |
| Specific energy intensity | 150-220 W*h/kg |
| C-rated charging | 0.7-1C, charging up to 4.20 V, in some models up to 4.30 V; the charging process usually takes 3 hours; Charging current greater than 1C shortens battery life |
| C-rating rank | 1C; some models support 2C; at 2.50 V, the cutoff is activated |
| Number of charge/discharge cycles | |
| thermal breakdown | Usually at 210°C. Full charge promotes thermal runaway |
| Areas of use | E-bikes, medical equipment, electric cars, industry |
| Comment | Provide high capacity and power. Wide range of practical applications, market share is growing rapidly |
Table 8: Lithium Nickel Manganese Cobalt Oxide (NMC) battery specifications.
4. Lithium iron phosphate battery (LiFePO4)
In 1996, research was conducted at the University of Texas, as a result of which a new material for the cathode was discovered. lithium ion battery- iron phosphate. The lithium phosphate system has good electrochemical properties and low internal resistance. The main advantages of such batteries are high amperage and long service life, in addition, they have good thermal stability, increased safety and resistance to misuse.
Lithium phosphate batteries are more resistant to overcharging; if a high voltage is applied to them for a long time, then the degradation effects will be noticeably less in comparison with other lithium-ion batteries. But a cell voltage of 3.20 V reduces the specific energy density to a level even lower than that of a lithium-manganese battery. For most electric batteries, cold temperatures reduce performance and hot temperatures shorten life, the lithium phosphate system is no exception. It also has a higher self-discharge rate than other lithium-ion batteries. Figure 9 shows the characteristics of a lithium phosphate battery.
Lithium phosphate batteries are often used as replacements for starter lead acid batteries. Four cells of such a battery will provide a voltage of 12.8 V - similar to the voltage of six two-volt lead-acid cells. The vehicle's alternator recharges the lead-acid battery to 14.40V (2.40V per cell). For four lithium phosphate cells, the voltage limit will be 3.60V, after recharging, it should be turned off, which does not happen in a conventional vehicle. Lithium phosphate batteries are resistant to overcharging, but even they degrade if they are kept at high voltage for a long time. Low temperatures can also be a problem when using a lithium phosphate battery as a replacement for a conventional starter.
Figure 9: Evaluation of the performance of a lithium phosphate battery. The lithium phosphate electrochemical system provides excellent safety and long life, but the energy density is moderate and the self-discharge is high.
Characteristic table
| Lithium ferrophosphate: LiFePO4 cathode, graphite anode Abbreviation: LFP or Li-phosphate |
|
| Voltage | 3.20, 3.30 V nominal; standard operating range - 2.5-3.65 V per cell |
| Specific energy intensity | 90-120 W*h/kg |
| C-rated charging | 1C standard, charging up to 3.65V; the charging process usually takes 3 hours |
| C-rating rank | 1C; in some versions up to 25C; 40 A surge currents (up to 2 seconds); at 2.50 V, the cut-off is activated (voltage below 2 V is harmful) |
| Number of charge/discharge cycles | 1000-2000 (depending on depth of discharges and temperature) |
| thermal breakdown | 270°C. Safe even when fully charged |
| Areas of use | Portable and stationary devices where high load currents and endurance are required |
Greetings, my dear friends and admirers, readers of this blog. Instead of another lesson, it’s more correct to say articles in photo school piggy bank, I decided to write an article about a sore topic and important for everyone.
I think for many, including you, my dear readers, it will be both interesting and useful to know what is so fundamental about lithium-ion batteries, what are their limits, how they should be used, what can be obtained with proper use, and of course, what should be the care, for long battery life. So go ahead.
What for? - you ask me, I generally started a scribble on this topic. Well, a battery and a battery and what's with it. So? An no. Li-ion battery, this is essentially a fuel tank for many of our favorite devices, and in the common people devices. So what? - you tell me, - what difference does it make to us? And the difference is big and important to you. The idea to write this article appeared after we went to photography school with students. The weather conditions are quite mediocre about -7 -10 Celsius, the sun, a light breeze, clear. Pleasant weather in general, for the inquisitive eye of the amateur photographer. However, many students were worried: Isn't it dangerous for the camera? Will she freeze? What happens if it freezes? (I will write a separate note about the temperature regimes of the camera operation) And what will happen to the camera battery? We heard that the camera battery is very afraid of the cold and can fail, is this true? True, but not all and not entirely. Let's figure it out.
In our cameras with you, there are lithium-ion batteries. What would that mean? And here's what. Li-ion batteries have significantly better usage parameters compared to other types of batteries. I will not go into details, but nowadays, most consumer electronics manufacturers are trying to supply their products with Li-ion batteries, as they are simpler and cheaper to manufacture and less harmful to the environment.
Primary cells ("batteries") with a lithium anode appeared in the early 70s of the 20th century and quickly found application due to their high energy density and other advantages. Thus, a long-standing desire was realized to create a chemical current source with the most active reducing agent - an alkali metal, which made it possible to sharply increase both the operating voltage of the battery and its specific energy. If the development of primary cells with a lithium anode was crowned with relatively quick success and such cells firmly took their place as power sources for portable equipment, then the creation of lithium batteries ran into fundamental difficulties, which took more than 20 years to overcome.
After a lot of testing during the 1980s, it turned out that the problem of lithium batteries revolved around lithium electrodes. More precisely, around the activity of lithium: the processes that occurred during operation, in the end, led to a violent reaction, called "ventilation with the release of a flame." In 1991, a large number of lithium batteries, which were first used as a power source for mobile phones, were recalled to manufacturers. The reason is that during a conversation, when the current consumed is maximum, a flame erupted from the battery, burning the face of the mobile phone user.
Due to the inherent instability of lithium metal, especially during the charging process, research has shifted to the field of creating a battery without the use of Li, but using its ions. Although lithium-ion batteries provide a slightly lower energy density than lithium batteries, Li-ion batteries are nevertheless safe when provided with the correct charge and discharge modes.
If further, someone is interested and interested in the part about what chemical processes were and are in lithium-ion batteries, how these very processes were tamed, then go to Google. I am not strong enough in chemistry and physics to write an article from reading which I will fall asleep myself.
Modern Li-ion batteries have high specific characteristics: 100-180 Wh/kg and 250-400 Wh/l. Operating voltage - 3.5-3.7 V.
If a few years ago, developers-manufacturers considered the maximum achievable - the capacity of Li-ion batteries is not higher than a few ampere-hours (remember the school physics course), now most of the reasons limiting the increase in capacity have been overcome and many manufacturers began to produce batteries with a capacity of hundreds of amperes hours, or even thousands.
Modern small-sized batteries are efficient at discharge currents up to 2 C, powerful ones - up to 10-20 C. Operating temperature range: from -20 to +60 °С. However, many manufacturers have already developed batteries that can operate at -40 °C. It is possible to extend the temperature range to higher temperatures.
The self-discharge of Li-ion batteries is 4-6% for the first month, then it is much less: in 12 months, the batteries lose 10-20% of their stored capacity. The capacity loss of Li-ion batteries is several times less than that of nickel-cadmium (Ni-Cd) batteries, both at 20 °C and at 40 °C. Resource of lithium-ion batteries: 500-1000 charge-discharge cycles.
And here, many will say: -Aaaaa. That's why you can shoot with a camera at moderately low temperatures. Yes, I will answer you. Plus, when a battery is working to deliver energy, chemical reactions occur within the battery, the side effect of which is the release of heat energy, allowing the battery to maintain its operating temperature range longer. In addition, when we take the camera out of the case, on the street, it (camera, camera) also has a positive temperature, that is, we still increase the time resource during which we can shoot outdoors at -7 ..-15 °C. Add to this the thermal heating of the camera processor during shooting, the heating of the matrix, even the warmth of the hands with which we hold the camera and pass it on, prolongs the thermal and temporary life of the camera at moderately low temperatures.
This is with regard to the use of batteries in operation. Now let's look at the charging and storage side for a bit. Lithium-ion batteries do not require any special care. The basic rules for their operation can be found in the instructions for the phone / laptop / camera, and everything else is taken care of by the BMS circuit and the charge controller in the powered device. Nevertheless, when buying, you can often hear the following statements from a seller or a “guru” friend:
“…the first charge is 12–15 hours…” or, alternatively, “…just leave the device plugged in all night…”;
"... you need to do 3-5 full cycles for the battery to gain capacity ...";
“... it is desirable to charge and discharge the battery completely ...”;
“... so what if the battery is already a year old, it has not been used; its service life depends solely on the number of charge-discharge cycles ... ".
Let's see how the above is true.
The first statement is simply meaningless - the control electronics will not allow you to charge the battery more than it should.
Tip #2 is also untenable. Lithium-ion batteries work with full efficiency after the first charge, and at first they are discharged faster simply because the owner of the device sets up and studies it, demonstrates it to friends and acquaintances, etc. After a week or two, the gadget enters normal mode, which, naturally , has a positive effect on autonomy. But one full charge before use is still desirable. This is not necessary for the battery, but so that the device can determine its real capacity and subsequently correctly display the remaining charge.
Recommendation No. 3 “legs grow” from the rules for operating nickel-cadmium batteries, which had to be completely discharged first, otherwise part of the capacity was irreversibly lost. Their lithium-ion counterparts do not have such a “memory effect”, moreover, deep discharge is contraindicated for them. With frequent use, this is irrelevant, since the BMS system does not allow the battery to be completely discharged, but if it stays in a discharged state for a month or more, the remaining charge will “leak”, the protection circuit will block the charging process and turn off, after which charging will no longer be possible. Overcharging is also harmful, but in most devices this is already taken into account, and they charge the battery not up to 100%.
There is also advice like "charge as you wish, but at least once a week (month) cycle completely." This scheme of operation is optimal for nickel-metal hydride batteries - they also have a memory effect, but much less than Ni-Cd, and restore capacity after 1-2 full cycles. For lithium-ion batteries, this is only partially true, for example, it is recommended to do it after a long period of storage.
From statement number 4, a seemingly logical conclusion follows: since the battery life is measured by the number of cycles, it means that it is better to use it to the maximum. This is mistake. Full charge and discharge wear it out faster, and incomplete cycles, on the contrary, prolong life. In addition, lithium-ion batteries lose capacity even without use. Already after a year "on the shelf" their resource is reduced by 5-10%, after 2 years - by 20-30%. Therefore, when purchasing a new portable device, pay attention to the release date of the power supply. It is also obvious that buying a battery "for future use", even if it is difficult to find it on sale, is useless.
It is very important to observe the operating temperature of lithium-ion batteries. In frost below -20 ° C, they simply stop giving current, and in heat above +45 ° C, although they function, such climatic conditions activate the aging process, significantly reducing the life of the battery. But you can charge it only at positive (Celsius) temperatures, otherwise there is a high risk of device failure. In general, the optimum operating temperature for lithium-ion batteries is +20°C.
Lithium-ion batteries are constantly being improved, manufacturers are actively experimenting with electrode and electrolyte materials. In 1994, batteries with lithium-manganese cathodes appeared, and in 1996 - with lithium-iron-phosphate cathodes. They are much more stable and easily carry a large discharge current, so they have found application in power tools and electric vehicles. Since 2003, batteries have been produced that use a complex cathode composition (LiNiMnCoO2) and have the best combination of characteristics among all listed. But no one has yet been able to surpass lithium-cobalt specimens in terms of specific capacity and price, and the advantages of new types are not in demand in mobile phones and laptops that consume relatively low current.
If you have temporarily put your device away, but want to keep its battery in working condition, you should know that lithium-ion batteries are best stored at a temperature of about +5 ° C. The higher it is and the closer the degree of charge to 100%, the faster the battery ages and loses capacity. It is best to charge it up to 40–50%, remove it from the device, pack it in a sealed plastic bag, put it in the refrigerator (but not in the freezer!) And recharge it periodically.
That's all I wanted to say about batteries, our friends, electronic pets. Whether it's a phone, player or camera.
This article was prepared based on materials found on the Internet and collected here in a pile for convenience and understanding of the essence of the process.
Have questions? Write in the comments and I will definitely answer.
P.S. Friends, if you liked the article or found it useful to you. Do me a favor too. Share the link to the article on your pages "Vkontakte", "Odnoklassniki", "Facebook", "Tweeter" and other pages. To do this, just click the buttons at the bottom of the page and follow the simple steps of the instructions. I also invite you to subscribe to my newsletter, then you definitely will not miss the next, I hope interesting and useful article. The subscription form is in the top right corner of the page.
Permissible temperature ranges for charging and discharging lithium-ion batteries
Testing Features
Tests for the number of cycles were carried out at a discharge current of 1C, for each battery, discharge / charge cycles were carried out until reaching 80% capacity. This number was chosen based on the timing of the test and for possible comparison of the results subsequently. The number of full equivalent cycles is up to 7500 in some tests.Life tests were carried out at various charge levels and temperatures, voltage measurements were taken every 40-50 days to control the discharge, the duration of the tests was 400-500 days.
The main difficulty in the experiments is the discrepancy between the declared capacity and the real one. All batteries have a capacity higher than stated, from 0.1% to 5%, which introduces an additional element of unpredictability.
The most commonly used batteries were NCA and NMC, but lithium cobalt and lithium phosphate batteries were also tested.
Few terms:
DoD - Depth of Discharge - depth of discharge.
SoC - State of Charge - charge level.
Battery use
The number of cycles
At the moment, there is a theory that the dependence of the number of cycles that a battery can withstand on the degree of battery discharge in a cycle has the following form (blue indicates discharge cycles, black indicates equivalent full cycles):This curve is called the Wöhler curve. The basic idea came from mechanics about the dependence of the number of stretches of a spring on the degree of stretching. The initial value of 3000 cycles at 100% battery discharge is a weighted average of 0.1C discharge. Some batteries show better results, some worse. At a current of 1C, the number of full cycles at 100% discharge drops from 3000 to 1000-1500, depending on the manufacturer.
In general, this ratio, presented in the graphs, was confirmed by the results of experiments, because it is advisable to charge the battery whenever possible.
Cycle superposition calculation
When using batteries, it is possible to work with two cycles simultaneously (for example, regenerative braking in a car):
This results in the following combined cycle:
The question arises, how does this affect the operation of the battery, is the battery life greatly reduced?
According to the results of the experiments, the combined cycle showed results, both from the addition of full equivalent cycles of two independent cycles. Those. the relative capacity of the battery in the combined cycle fell according to the sum of discharges in the small and large cycles (linearized graph is presented below). 
The effect of long discharge cycles is more significant, which means that the battery is better charged at every opportunity.
memory effect
The memory effect of lithium-ion batteries was not observed according to the results of the experiments. Under various modes, its full capacity still subsequently did not change. At the same time, there are a number of studies that confirm the presence of this effect in lithium-phosphate and lithium-titanium batteries.Battery storage
Storage temperatures
No unusual discoveries were made here. Temperatures 20-25°C are optimal (in normal life) for battery storage if not used. When the battery is stored at a temperature of 50°C, capacity degradation is almost 6 times faster.Naturally, lower temperatures are better for storage, but in everyday life this means special refrigeration. Since the air temperature in the apartment is usually 20-25°C, then storage is likely to be at this temperature.
Charge level
As tests have shown, the lower the charge, the slower the self-discharge of the battery. The capacity of the battery was measured, whatever it would be during its further use after long-term storage. The best result was shown by batteries that were stored with a charge close to zero.In general, good results were shown by batteries that were stored with no more than 60% charge level at the time of storage. The figures differ from those given below for a 100% charge for the worse (i.e., the battery will become unusable earlier than indicated in the figure):
The figure is taken from article 5 practical tips for the operation of lithium-ion batteries
At the same time, the figures for low charge are more optimistic (94% after a year at 40°C for storage at 40% SOC).
Since a 10% charge is impractical, since the operating time at this level is very short, store batteries optimally at SOC 60%, which will allow you to apply it at any time and will not critically affect its service life.
Main problems of experimental results
No one has conducted tests that can be considered 100% reliable. The sample, as a rule, does not exceed a couple of thousand batteries out of millions produced. Most researchers are unable to provide reliable comparative analyzes due to undersampling reasons. Also, the results of these experiments are often confidential information. So these recommendations do not necessarily apply to your battery, but may be considered optimal.Results of experiments
Optimum charging frequency - at every opportunity.Optimal storage conditions - 20-25°C at 60% battery charge.
