Correct charging method for lithium batteries

The life of electricity is generally 300-500 charge cycles. Assuming that the amount of power supplied by a full discharge is 1Q, if the power consumption is reduced after each charging cycle, the lithium battery can provide or supplement 300Q-500Q power in its lifetime. Therefore, if you charge 1/2 each time, you can charge 600-1000 times; if you charge 1/3 each time, you can charge 900-1500 times. By analogy, if you charge randomly, the number of times is variable. In short, no matter how charged, the total power added to 300Q-500Q is constant. Therefore, we can also understand that the life of the lithium battery is related to the total charge of the battery, regardless of the number of times of charging. The effect of deep charge and shallow charge on lithium battery life is not much different. Then, some manufacturers said in the propaganda, "A certain strong lithium battery can be charged more than 1500 times." This is purely bullying consumers’ ignorance.

In fact, shallow charge is more beneficial for lithium battery. Only when the power module of the product is calibrated for lithium battery, it is necessary to deep charge. Therefore, products that use lithium-ion power supply do not have to be constrained by the process. Everything is convenient and can be charged at any time without worrying about affecting life.

For the use of lithium-ion batteries, pay attention to three points:

1. How to charge a new battery

In the use of lithium batteries, it should be noted that after the battery is placed for a period of time, it enters a sleep state. At this time, the capacity is lower than the normal value, and the use time is also shortened. However, the lithium battery is easy to activate, as long as the battery is activated after 3 to 5 normal charge and discharge cycles, and the normal capacity is restored. Due to the characteristics of the lithium battery itself, it is determined that it has almost no memory effect. Therefore, the user's new lithium battery does not require special methods and equipment during the activation process. Not only in theory, but from my own practice, it is best to use a standard method of charging this "natural activation" method from the beginning.

For the "activation" problem of lithium batteries, many sayings are: charging time must be more than 12 hours, repeated three times in order to activate the battery. This statement that "the first three charges have to be charged for more than 12 hours" is obviously a continuation of the nickel battery (such as nickel cadmium and nickel hydride). So this kind of statement can be said to be misinformation at the beginning. The charge and discharge characteristics of lithium and nickel batteries are very different, and it is very clear to tell you that all the serious official technical information I have reviewed emphasizes that overcharge and over discharge will be lithium batteries, especially liquid lithium. Ion batteries cause great damage. Therefore, charging is preferably performed in accordance with standard time and standard methods, especially for ultra-long charging of more than 12 hours.

In addition, the lithium battery or charger will automatically stop charging when the battery is fully charged, and there is no so-called “turbulent” charging that the nickel battery charger has for 10 hours. In other words, if your lithium battery is full, it will be white charger on the charger. And none of us can guarantee that the characteristics of the battery's charge and discharge protection circuit will never change and the quality will be foolproof, so your battery will be on the edge of danger for a long time. This is another reason why we oppose long charging.

In addition, on some machines, after charging for more than a certain period of time, if you do not remove the charger, then the system will not stop charging, and will start the discharge-charge cycle. Perhaps the manufacturer of this approach has its own purpose, but it is obviously not good for the life of the battery. At the same time, long charging takes a long time and often needs to be carried out at night. In the case of China's power grid, the voltage at night is high in many places and fluctuates greatly. As mentioned above, the lithium battery is very delicate, it is much less resistant to fluctuations in charge and discharge than nickel, and this brings additional danger.

In addition, another aspect that cannot be ignored is that lithium batteries are also not suitable for over-discharge, and over-discharge is also disadvantageous for lithium batteries. This leads to the following problem.

2. When should I start charging during normal use?

Since the number of charge and discharge cycles is limited, the power of the lithium battery should be recharged as much as possible. But I found an experimental table on the charge and discharge cycle of lithium-ion batteries. The data on cycle life are listed below:

Cycle life (10% DOD) : >1000 times

Cycle life (100% DOD) : >200 times

Among them, DOD is the abbreviation of depth of discharge. As can be seen from the table, the number of chargeable is related to the depth of discharge, and the cycle life at 10% DOD is much longer than that of 100% DOD. Of course, if you convert to the relative total capacity of the actual charge: 10% * 1000 = 100, 100% * 200 = 200, the latter's full charge and discharge is still better, but the former netizen's statement to do some correction: in normal In this case, you should reserve the charge according to the principle that the remaining battery power is used up and recharge, but if your battery is not likely to stick to the whole day on the 2nd day, you should start charging in time. Of course, if you are willing to carry it back, it’s a different matter to get the charger to the office.

And you need to charge to cope with the expected important events that will cause the communication to be busy, even if the battery still has a lot of power then you only charge in advance because it has not really lost "1" charging cycle life. That is, "0.x" times, and often this x will be small.

The principle that the remaining battery power is used up and refilled is not to go to extremes. One of the more widely spread arguments like long charging is that "try to run out of battery power, it is best to use automatic shutdown." This practice is actually only a nickel battery. The purpose is to avoid memory effects. Unfortunately it is also circulating on lithium batteries. Some people have used the example of automatic shutdown since they have been warning that the machine's battery is too low. As a result, the machine in this example did not respond during the subsequent charging and booting, and had to be sent to the customer for maintenance. This is actually caused by the battery being over-discharged and the voltage is too low, so that it does not have normal charging and power-on conditions.

3, the correct approach to lithium batteries

To sum up, the most important tips for charging and discharging lithium batteries in use are:

1. Charge according to standard time and procedures, even if it is the first three times;

2. When the machine is too low, you should start charging as soon as possible;

3. The activation of the lithium battery does not require a special method. The lithium battery will naturally activate during normal use of the machine. If you insist on using the "first three 12-hour long charge activation" method that is circulated, it will not actually work.

Therefore, all the pursuit of 12 hours of ultra-long charging and the use of lithium batteries to automatically shut down is wrong. If you have done it in the wrong way, please correct it in time, maybe it is not too late.

4. Use lithium batteries to pay attention to fire

Many people may be familiar with lithium batteries from mobile phones. In fact, it is used in many home appliances. Undoubtedly, the advantages of high efficiency and light weight of lithium batteries are promptly popularizing and applying them. However, do you know that if you use it carelessly, it will also make you "fire" the upper body?

The lithium battery has the advantages of light weight, high efficiency, low temperature resistance (-40 ° C), etc. The 0.3 mm thick, stamp-sized lithium battery can be used continuously for more than 5 years. In recent years, the existing alkaline dry battery and manganese battery are being phased out. Widely used in many high-end appliances and mobile phones.

The lithium battery is different from the zinc chloride and potassium hydroxide water-soluble electrolyte of the existing manganese battery and the alkaline dry battery, and it uses an organic solvent. The positive electrode of the lithium battery is made of manganese dioxide, lead fluoride or thionyl chloride. The lithium metal foil used for the negative electrode has a stronger ionization tendency and a larger voltage difference between the positive and negative electrodes than the zinc chloride used in the negative electrode of a general battery, thereby improving the working efficiency of the lithium battery.

However, lithium batteries often have heat and burning during use, which affects the use of the host, and severely burns the host to cause a fire. According to reports, in Japan in recent years, there have been many home fire accidents caused by the burning of lithium batteries.

Then why does the lithium battery heat up and burn? Many of the materials in lithium batteries can be exposed to water and can undergo a violent chemical reaction and release a large amount of heat to cause heat and combustion. The manganese dioxide of the positive electrode of a lithium battery can be heated only by a small drop of water. After the contact of thionyl chloride in water with lithium, the release of heat energy while generating hydrochloric acid and sulfur dioxide, several factors make the lithium battery become a "fire" in life, so people must pay attention to waterproof and anti-proof when using lithium batteries moist. After the various hosts are deactivated, the lithium battery should be taken away from the dry and low temperature for proper storage to prevent and avoid the occurrence of household fire accidents caused by improper use of the lithium battery.

Lithium polymer battery, also known as polymer lithium battery, is a new generation of lithium battery, which has the advantages of high energy density, light weight, flexibility, ultra-thinness, and can be made into any shape. The same volume lithium polymer battery could double the capacity of a typical lithium battery, and the cost is lower and the safety is higher. Generally, the aluminum-plastic packaging of lithium polymer batteries, if there is a safety problem, will only bulge and will not explode like Samsung Note7.

The page contains the contents of the machine translation.