Mastering the use and maintenance techniques of lithium-ion batteries can extend the service life of lithium-ion batteries and maintain the excellent performance of the battery.

　　Lithium-ion battery discharge

　　Discharge stop voltage: The rated voltage of lithium-ion battery is 3.6V (some products are 3.7V), and the discharge stop voltage is 2.5-2.75V (the battery factory gives the operating voltage plan or the stop discharge voltage, each parameter is slightly different ). The discharge termination voltage of the battery should not be less than 2.5 (n is in series

　　Number of batteries), continuous discharge below the discharge stop voltage is called over-discharge. Over-discharge will shorten the battery life, and in severe cases, it will cause battery failure. When the battery is not in use, the battery should be charged until it retains 20% of its capacity, and then stored in moisture-proof packaging. The voltage should be checked once every 3 to 6 months and charged to ensure that the battery voltage is within the safe voltage value (above 3V).

　　Discharge current: Lithium-ion batteries are not suitable for high-current discharge. When excessive current is discharged, a higher internal temperature will occur and energy will be lost, reducing the battery life.

　　During the discharge time, if there are no protective components in the battery, overheating will occur and damage the battery. Therefore, the maximum discharge current given by the battery production factory should not exceed the maximum discharge current given in the product characteristics table during use.

　　Discharge temperature: The discharge curves at different temperatures are different. At different temperatures, the discharge voltage and discharge time of lithium-ion batteries are also different.

　　The battery should be discharged (operated) within the temperature range of -20°C to +60°C.

　　Lithium-ion battery charging

　　What should be noted when using lithium batteries is that the battery enters a dormant state after being left for a period of time. At this time, the capacity is lower than the normal value and the use time is also shortened. However, lithium batteries are very easy to activate. As long as 3-5 normal charge and discharge cycles are used, the battery can be activated and restored to normal capacity. Due to the characteristics of lithium batteries, they have almost no memory effect. Therefore, the new lithium battery in the user's mobile phone does not require special methods and equipment during the activation process.

　　To charge lithium-ion batteries, a dedicated lithium-ion battery charger should be used. Lithium-ion battery charging adopts the "constant current/constant voltage" method. Constant current charging is performed first, and when it is close to the cut-off voltage, it is changed to constant voltage charging. For example, a battery with a capacity of 800mA.h has a charging voltage of 4.2V. The battery is

　　800mA (charge rate 1C) constant current charging. At the beginning, the battery voltage rises with a large slope. When the battery voltage is close to 4.2V, it changes to

　　4.2V constant voltage charging, the lithium battery current gradually decreases, and the voltage does not change much. When the charging current drops to 1/10C (about 80mA), it is considered that the battery is close to the charger.

　　When the battery is full, charging can be stopped (some chargers start a timer after reaching 10C and complete charging after a certain period of time). Do not use rechargeable nickel-cadmium batteries

　　Use electrical appliances (three-cell nickel-cadmium batteries) to charge lithium-ion batteries (although the rated voltage is the same, 3.6V). Due to the different charging methods, it is easy to cause overcharge.

　　Charging voltage: The charging stop voltage when fully charged is related to the battery negative electrode material. Coke is 4.1V, while graphite is 4.2V. They are generally called 4.1V lithium-ion batteries and 4.2V lithium-ion batteries. When charging, please note that 4.1V batteries cannot be charged with a 4.2V charger, otherwise there will be a risk of overcharging.

　　(4.1V and 4.2V chargers use different charger ICs). Lithium-ion batteries have very high charging requirements and require sophisticated charging circuits to ensure charging safety. The tolerance of the charging voltage accuracy is ±1% of the additional value (for example, when charging a 4.2V lithium-ion battery, the tolerance is

　　±0.042V), overvoltage charging will cause permanent damage to the lithium-ion battery.

　　Charging current: Lithium-ion battery charging current should be based on the battery manufacturer's recommendations and requires a current-limiting circuit to prevent overcurrent (overheating). The commonly used charging rate is 0.25~1C, and the recommended charging current is 0.5C (C is the capacity of the battery, such as a battery with a nominal capacity of 1500mA.h.

　　Charging current 0.5*1500=750mA). When charging with high current, it is often necessary to detect the battery temperature to prevent battery damage or explosion due to overheating.

　　Charging temperature: When charging the battery, its ambient temperature cannot exceed the temperature plan listed in the product characteristics table. The battery should be in the temperature range of 0~45℃

　　Charge in a safe environment, away from high temperature (above 60℃) and low temperature (-20℃) environments.

　　If a lithium-ion battery is overcharged, overdischarged or overcurrent during the charging or discharging process, it will cause damage to the battery or reduce its service life. Open for this

　　It emits various protection components and protection circuits composed of protection ICs, which are installed in the battery or battery pack to provide complete protection for the battery. But

　　Overcharge and overdischarge should be avoided as much as possible during use. For example, when the mobile phone battery is charging, it should be separated from the charger in time when it is almost full.

　　Leave. When the discharge depth is shallow, the cycle life will be significantly improved. Therefore, when using it, do not wait until a low battery signal appears on your phone before charging it.

　　Please do not continue to use it when this signal appears, although there is still some residual capacity available for use when this signal appears.

　　storage and shipping

　　Lithium-ion batteries can be stored in a clean, dry, and ventilated environment with a temperature of -5 to 35°C and a relative humidity of no more than 75%. They should be prevented from corrosion.

　　If it comes into contact with sexual substances, keep away from fire and heat sources. Do not place it in direct sunlight. Do not disassemble the battery at will. If the battery is stored for a long time, the battery

　　The capacity should be maintained at 30% to 50% of the nominal capacity. It is recommended that the stored batteries be charged every 6 months.

　　Batteries should be packed into boxes for transportation. During transportation, they should avoid violent vibration, impact or squeezing, and avoid exposure to sunlight and rain. Automobiles can be used.

　　Cars, trains, ships, airplanes and other means of transportation are used for transportation.

　　short circuit

　　Regarding the safety issues of lithium-ion batteries, friends, please pay attention. Lithium-ion batteries are prone to short circuits during charging.

　　Although most lithium-ion batteries have protection circuits against short circuits and explosion-proof wires. But in many cases, this circuit works in various situations,

　　It doesn't necessarily work. The effect of explosion-proof wires is also very limited.

　　overcharge

　　All lithium-ion batteries, including polymer lithium-ion batteries, lithium iron batteries, etc., are very afraid of overcharging.

　　If the lithium-ion battery is charged for too long, the possibility of explosion will increase.

　　The chemical properties of lithium are very active and easy to burn. When the battery is charged and discharged, the temperature inside the battery continues to rise, and the gas generated during the activation process expands.

　　expansion, causing the internal pressure of the battery to increase. When the pressure reaches a certain level, if the outer shell is damaged, it will rupture, causing leakage, fire, or even explosion.

　　Therefore, we must pay great attention to safety when using lithium-ion batteries.

　　Charge

　　Charging is an important process for repeated use of batteries. The charging process of lithium-ion batteries is divided into two stages: constant current fast charging stage and constant voltage current decreasing stage.

　　part. In the constant current fast charging stage, the battery voltage gradually rises to the battery's standard voltage, and then switches to the constant voltage stage under the control chip, and the voltage no longer rises.

　　High to ensure that it will not be overcharged, the current will gradually weaken to the set value as the battery power increases, and charging will eventually be completed. Power calculation chip pass

　　By recording the discharge curve, the battery capacity can be calculated by sampling. After repeated use of lithium-ion batteries, the discharge curve will change.

　　Although the battery does not have a memory effect, improper charging and discharging will seriously affect the battery performance.

　　Charging precautions

　　Excessive charging and discharging of lithium-ion batteries will cause permanent damage to the positive and negative electrodes. Excessive discharge causes the negative electrode carbon sheet structure to collapse, and the collapse will cause

　　During the charging process, lithium ions cannot penetrate; overcharging causes too many lithium ions to be embedded in the carbon structure of the negative electrode, causing some of the lithium ions to no longer be able to penetrate.

　　The law is released.

　　The charging capacity is equal to the charging current multiplied by the charging time. When the charging control voltage is certain, the larger the charging current (the faster the charging speed), the higher the charging speed.

　　The smaller the amount of electricity. Excessive battery charging speed and improper stop voltage control point will also cause insufficient battery capacity. In fact, part of the battery's power

　　The extremely active material stops charging without sufficient reaction, and this phenomenon of insufficient charging intensifies as the number of cycles increases.

　　discharge

　　For the first charge and discharge, if the time can be longer (usually 3-4 hours is enough), then the electrode can reach the highest oxidation state as much as possible (enough to

　　(electricity), when discharging (or using), it is forced to the specified voltage, or until it automatically shuts down, which can activate the battery usage capacity.

　　However, in the daily use of lithium-ion batteries, there is no need to do this. It can be charged at any time as needed. It is not necessary to be fully charged when charging.

　　Stop, no need to discharge first. Operations like initial charge and discharge only need to be performed 1-2 times every 3-4 months.

　　Internal short circuit protection

　　Due to the influence of many factors such as material system and manufacturing process, lithium-ion batteries are at risk of internal short circuit. Although lithium-ion batteries are

　　They have passed strict aging and self-discharge selections before leaving the factory. However, due to process failures and other unpredictable application factors, there are still some problems.

　　A certain probability of failure leads to internal short circuit during use. Regarding power batteries, there are hundreds or even tens of thousands of lithium-ion batteries in the battery pack.

　　section, which greatly increases the probability of internal short-circuit in the battery pack. Due to the huge energy contained inside the power battery pack, the occurrence of internal short circuit can easily be induced.

　　Vicious accidents, resulting in casualties and property losses.

　　For parallel-connected lithium-ion power battery modules, when one or several batteries are short-circuited, the other batteries in the battery module will discharge it.

　　The energy of the battery pack will cause the temperature of the internal battery to rise rapidly, which can easily induce thermal runaway and eventually cause the battery to catch fire and explode.

　　Although the conventional temperature measurement can tell the IC to cut off the main circuit when the battery heats up, it cannot prevent the continuous discharge inside the parallel battery module.

　　Moreover, due to the cutoff of the main circuit, all the energy of the battery module is concentrated on the internal short-circuited battery, which increases the probability of thermal runaway.

　　The ideal plan is to cut off the connection loop between this battery and other batteries in the module when it is found that a certain battery is short-circuited and heated up. like

　　As shown in Figure 2, when TEPPTC or MHP-TA series products are assembled on a single battery, the TE protection device can effectively block when an internal short circuit occurs.

　　Internally short-circuited battery communicates with other batteries in the module to prevent serious accidents. Regarding power battery packs with a large number of single cells, when assembling

　　There are high requirements for the commonality of the internal resistance of the battery and the device. However, due to its internal bimetallic structure, the MHP-TA has very good commonality of the device resistance and can be used very efficiently.

　　The earth meets the requirements regarding the internal resistance of the battery.

　　The system composition of lithium-ion power batteries and the actual road conditions are complex, so the protection of passive components is essential.

　　Lithium battery advantages

　　1) High voltage

　　The operating voltage of a single battery is as high as 3.7-3.8V (lithium iron phosphate is 3.2V), which is three times that of Ni-Cd and Ni-MH batteries.

　　2) Greater than energy

　　The actual specific energy that can be achieved is about 555Wh/kg, that is, the material can achieve a specific capacity of more than 150mAh/g (3--4 times that of Ni-Cd, 2--3

　　Times that of Ni-MH), which is close to about 88% of its theoretical value.

　　3) Long cycle life

　　Generally, it can reach more than 500 times, or even more than 1,000 times, and lithium iron phosphate can reach more than 2,000 times. Regarding electrical appliances that discharge small currents, electricity

　　The service life of the pool will double the competitiveness of the appliance.

　　4) Good safety function

　　No pollution, no recall effect. As the predecessor of Li-ion

　　New lithium-ion battery

　　Lithium batteries, because metallic lithium can easily form dendrites and cause short circuits, which reduces its application areas: Li-ion does not contain cadmium, lead, mercury and other environmentally polluting chemicals.

　　Element: A major drawback of Ni-Cd batteries with some processes (such as sintered type) is the "memory effect", which severely restricts the use of batteries, but Liion does not have this problem at all.

　　5) Small self-discharge

　　The self-discharge rate of fully charged Li-ion after one month of storage at room temperature is about 2%, which is much lower than Ni-Cd's 25-30% and Ni-MH's 30-

　　35%.

　　6) Fast charging

　　The capacity of 1C charging can reach more than 80% of the nominal capacity in 30 minutes, and the iron phosphorus battery can be charged to 90% of the nominal capacity in 10 minutes.

　　7) Operating temperature

　　The operating temperature is -25~45°C. With the improvement of electrolyte and positive electrode, it is hoped to be expanded to -40~70°C.

　　Disadvantages of lithium batteries

　　1) Aging

　　Unlike other rechargeable batteries, the capacity of lithium-ion batteries will slowly decline, related to the number of uses and temperature. This phenomenon of decline

　　It can be indicated by a decrease in capacity or an increase in internal resistance.

　　Because it is related to temperature, it is easier to perform in electronic products with high operating current. Replacing graphite with lithium titanate seems to extend life. store

　　The relationship between temperature and the rate of permanent loss of capacity:

　　2) Recovery rate

　　About 1% of new products leaving the factory need to be recalled for various reasons.

　　3) Intolerant to overcharging

　　When overcharging, excessively embedded lithium ions will be permanently fixed in the crystal lattice and cannot be released again, which can lead to short battery life.

　　4) Intolerance to over-discharge

　　During over-discharge, too many lithium ions are deintercalated from the electrode, which can cause the crystal lattice to collapse, thus shortening the service life.

Read recommendations:

LR03

What are the advantages of lead -acid batteries?photovoltaic energy storage battery manufacturer

How does temperature change affect the charging and discharging of lithium batteries.LR1121 battery

energy storage battery guangdong manufacturer

402030 battery