Lithium battery charging times and cycle life

Normal call is "charge and discharge cycle", is not equal to "charge times", cycle refers to, the battery from full charge to use up, this is a cycle, if your battery from full charge state, used a tenth of the power, and then full again, this is a tenth of a cycle, so charge 10 times, just basically count as a cycle. Once again, from full charge, you use half of it and then you fill it up, and then you use half of it and then you fill it up again, and this is a cycle, and then you charge it up twice. So the cycle simply depends on "the cumulative amount of energy released from the battery," not on "the number of charges."

And this nominal charge and discharge cycle number doesn't mean you can't use up, but after doing so many cycles, the battery's ability to store electricity will drop to a point.

For example, for a lithium battery, the nominal charge and discharge cycle is "no less than 60% of the nominal capacity after 500 times".

After 500 cycles, the battery can only store 60% of the power of the new battery

Lithium battery has no fixed charge times limit, the regular manufacturers out of the battery can generally charge and discharge at least 500 times, and the capacity to maintain more than 80% of the initial capacity, a day a charge can be used for 2 years. Normally, a mobile phone battery will not last long after being charged 1000 times.

Mobile phone battery maintenance method:

1, each fully charged use, reduce the number of charges, improve the service life of the battery.

2, do not fully discharge the battery, usually less than 10% of the power needs to be charged.

3, use the original charger to charge, do not use universal charging.

4. Do not use your mobile phone during charging.

5, do not overcharge, the battery is full of stop charging.

Yes, according to the experimental results, the life of lithium battery decreases with the increase of charging times. Generally, the charging times of lithium battery are 2000-3000 times

Cycle is the use, we are using the battery, is concerned about the use of time, in order to measure the rechargeable battery can be used for how long such a performance, the definition of cycle number. Actual users use a variety of conditions, because different conditions of the test is not comparable, to have a comparison must standardize the definition of cycle life.

Lithium battery cycle life test conditions prescribed by the national standard and requirement: the environment temperature is 20 ℃ under the condition of + 5 ℃, 1 c to charge, when the voltage of the battery to charge limit voltage of 4.2 V, instead of constant voltage charging, until the charging current is equal to or less than 1/20 c, stop charging, shelved 0.5 h ~ 1 h, then in 1 c discharge current to termination voltage 2.75 V, after the discharge, suspended 0.5 h ~ 1 h, then the next recharge cycles, until two consecutive discharge time is less than 36 min, thinks life is terminated, cycle number must be greater than 300 times.

Interpretation of national standard provisions:

A. This definition stipulates that the cycle life test shall be conducted in A deep charge and discharge manner

B. The cycle life of lithium battery is stipulated. According to this mode, after more than 300 cycles, the capacity is still more than 60%

However, different cycles of the circulation system is very different, such as more than the other conditions unchanged, only change the constant-voltage voltage of 4.2 V to 4.1 V voltage for the same model of the constant pressure of the battery cycle life test, so the battery is not deep filling way, the final test number of cycle life can be improved by almost 60%. If the cut-off voltage is increased to 3.9v for testing, the number of cycles should be increased by several times.

This is about the cycle charge and discharge of a life is less than once, we should pay attention to the definition of the lithium battery charging cycle: a charging cycle refers to the lithium battery all the electricity from full to empty, then from empty to full process of charging. This is not the same as charging once. In addition, when we talk about cycle times, we should not ignore the condition of cycle times. It is meaningless to talk about cycle times without rules, because cycle times are a means to detect battery life, not an end!

Myth: many people like to turn off their lithium-ion batteries and recharge them automatically.

In fact, it is impossible for users to use the battery in accordance with the national standard test mode. No mobile phone will be turned off until 2.75v, and its discharge mode is not large current constant current discharge, but GSM pulse discharge and low-current discharge mixed mode.

There's another way to measure cycle life, which is time. Some experts have proposed that the life of ordinary civilian lithium ion battery is 2~3 years, combined with the actual situation, such as 60% of the capacity of the life of the termination, plus the aging effect of lithium ion battery, with time to express the cycle life I think it is more reasonable.

Tips: for lithium ion battery, it is not necessary to shut down and recharge. Lithium ion battery is suitable for charging at any time. This is one of his biggest advantages for nickel metal hydride battery. Lithium battery full charge and discharge once (full charge and discharge is not the same as a charge and discharge), cycle life is reduced once.

The battery voltage (the black solid line in the figure) rises from a low value to a fixed value gradually, but the current (the black dotted line in the figure) remains unchanged. This is the most efficient period in the whole charging process, which is consistent with the feature that the phone is most efficient about 1 hour after charging.

When the voltage reaches a fixed value, the current gradually decreases and the charging efficiency also begins to decrease.

When the battery is charged, the current reaches the minimum value (about 3% of the initial current value), and the voltage remains at the highest value, which is also the time when the charging efficiency is the lowest. However, once this critical point is passed, the voltage begins to drop gradually and drops to a lower value.

After the voltage reaches a low value, the battery starts to generate some occasional charging, the current begins to flow again, and the voltage starts to rise again, until the phone's power indicator is full, at which point the voltage returns to the highest value.

Therefore, for the purpose of extending the service life of mobile phone battery, the best time for you to pull out the charging line is at the end of step 3, when the charging power displayed is about 80%.

Of course, if you think battery life is a priority (not battery life), you can ignore this.

Remove power cord immediately when battery is full

Many people have the habit of charging at night and pulling out the power cord the next morning, but this is bad for battery life.

Once you understand the principle above, it is not difficult to understand this point. Because your phone is always 100% charged, the battery is always at its highest voltage, which is bad for the battery -- if you're fully charged, pull out the power cord, which is not a problem, because the voltage inside the battery will always decrease after pulling out the power cord.