1. Is it true that the larger the charging current, the faster the charging?
For nickel-based batteries charged with constant current, it can be said that the higher the charging current, the faster the charging. For lithium-ion batteries, this is not entirely correct.
For lithium-ion battery charging, in a certain current range (1.5C~0.5C), increasing the constant current value of constant current and constant voltage charging mode can not shorten the time of filling lithium-ion battery.
2. Is the output current of the direct charging standard equal to the charging current?
This is to discuss the charging mode of mobile phone. For charging management in mobile phone, set the same output of direct charging (actually called power adapter), such as: 5.3V 600mA.
A. Charging management is switching mode (PWM mode with high frequency pulse width adjustment). In this charging mode, the mobile phone does not fully utilize the output capacity of direct charging. Direct charging works in the constant voltage section and outputs 5.3V. At this time, the real charging current is adjusted by the charge management of the mobile phone, and it must be less than 600 mA, generally in the range of 300-400 mA. At this time, you can see that the direct charging output current is not the charging current of the mobile phone. For example, many motorola's direct-charge output is 5.0V/1A, and 500 mA is enough to charge the battery, because the battery capacity of the mobile phone is only 580 mAh.
At this time, the output current of the direct charging superscript is not equal to the actual charging current.
B. Charging management is pulse mode. This charging mode makes full use of the current limiting current of direct charging, that is, 600 mA on the battery. At this time, the output current of direct charging is the charging current.
Of course, the above refers to the constant current stage of lithium-ion batteries or the charging of nickel-hydrogen batteries.
If there is no charge management, the charge management should be moved to direct charge. For example, many CDMA mobile phones are like this. There is nothing to say about it. Its output is very clear, such as output: 4.2V 500mA, which is the constant current and constant voltage data of lithium ion batteries.
3. Is one cycle charge-discharge life less than one cycle life?
Recycling is the use of batteries, we are concerned about the use of time, in order to measure how long a rechargeable battery can be used for such a performance, the number of cycles defined. Actual user use varies greatly, because the test under different conditions is incomparable. To compare, it is necessary to standardize the definition of cycle life.
The national standard stipulates the test conditions and requirements for the cycle life of lithium ion batteries: charging for 150 minutes at room temperature of 25 degrees with constant current and voltage 1C charging system, and discharging to 2.75V with constant current 1C discharging system as one cycle. When one discharge time is less than 36 minutes, the test is completed and the number of cycles must be more than 300.
Interpretation:
A. This definition stipulates that the cycle life test is conducted in a deep and in-depth manner.
B. It is stipulated that the cycle life must exceed 300 times after execution according to this mode, and the capacity will still exceed 60%.
In fact, the number of cycles obtained by different cycle systems is quite different. For example, the other conditions mentioned above remain unchanged. Simply changing the constant voltage of 4.2V to 4.1V to test the cycle life of the same type of battery, so that the battery is no longer a deep charging method. Finally, the cycle life is obtained by testing. The number of cycles can be increased by nearly 60%. If the cut-off voltage is increased to 3.9V for testing, the number of cycles should be increased several times.
Many friends have discussed the idea that one cycle is less than one life expectancy. I just add that when we talk about the number of cycles, we should not ignore the conditions of the cycle.
There is no point in discussing the number of cycles apart from the rules, because the number of cycles is a means of measuring battery life, not a goal!
Misconception: Many people like to use lithium-ion batteries in mobile phones to automatically shut down and recharge. This is completely unnecessary.
In fact, users can not use batteries according to the national standard test mode. No cell phone will shut down at 2.75V, and its discharge mode is not a high current constant current discharge, but a mixture of GSM pulse discharge and small current discharge.
There is another measure of cycle life, time. Some experts put forward that the life of lithium-ion batteries for general civil use is 2-3 years. Considering the actual situation, such as the termination of life with 60% capacity and the aging effect of lithium-ion batteries, I think it is more reasonable to use time to express the life of lithium-ion batteries.
The charging mechanism of lead-acid batteries is similar to that of lithium-ion batteries. It is a current-limiting and voltage-limiting method. It uses shallow charge and shallow discharge. Its life is expressed in terms of time, no number of times, such as 10 years.
Therefore, for lithium-ion batteries, there is no need to shut down and recharge. Lithium-ion batteries are suitable for use by charging at any time. This is also one of his greatest advantages for nickel-hydrogen batteries. Please make good use of this feature.
4. The higher the battery capacity, the better?
Different types of batteries (especially different volumes) have higher capacity and longer service life. Regardless of volume and weight, of course, the higher the capacity, the better.
But the nominal capacity (such as 600 mAh) of the same battery type is the same, and the initial capacity measured is different: for example, one is 660 mAh, the other is 605 mAh, then 660 mAh is better than 605 mAh?
The actual situation may be that the capacity is high because there are more things in the electrode material that increase the initial capacity and reduce the stabilization of the electrode.
