General FAQs for li-ion-battery(2)　

What is the internal resistance of the Battery?

Battery resistance is the Battery at work, the current flow through the battery internal resistance, generally divided into AC internal resistance and DC resistance, because the rechargeable battery internal resistance is very small, measured DC resistance due to electrode capacity polarization , Resulting in polarized internal resistance, it can not be measured its true value, and measured its internal resistance can be exempted from the impact of polarization resistance, the true value.

AC internal resistance test method is: the use of the battery equivalent to the characteristics of an active resistor to the battery a 1000HZ, 50mA constant current, the voltage sampling rectifier filter and a series of processing to accurately measure its resistance.

What is the battery internal pressure battery normal internal pressure is generally how much?
The internal pressure of the battery is caused by the gas generated during the charging and discharging process, which is mainly affected by the process factors such as the manufacturing process and structure of the battery material, etc. Generally, the internal pressure of the battery is maintained at the normal level, and in the case of overcharge or over discharge , The battery pressure may rise:

If the rate of the complex reaction is lower than the rate of the decomposition reaction, the resulting gas is too low to be consumed, resulting in an increase in the internal pressure of the battery.

What is internal pressure test?
Lithium Battery internal pressure test is: (UL standard)
Analog battery at an altitude of 15240m high altitude (low pressure 11.6kPa), check the battery is leak or drum.

Specific steps: the battery 1C charging constant current constant voltage charged to 4.2V, cut-off current 10mA, and then placed in the air pressure of 11.6Kpa, the temperature (20 +3) low pressure box storage for 6 hours, the battery will not explode, Fire, crack, leak.

How does ambient temperature affect battery performance?

In all environmental factors, the temperature has the greatest impact on the charge and discharge performance of the battery. The electrochemical reaction at the electrode / electrolyte interface is related to the ambient temperature. The electrode / electrolyte interface is regarded as the heart of the cell. If the temperature drops, the reaction rate of the electrode also decreases, assuming that the battery voltage remains constant, the discharge current decreases, the battery power output will drop. If the temperature rise is the opposite, that is, the battery output power will rise, the temperature also affects the transmission speed of the electrolyte is accelerated, the transmission temperature decreases, transmission slows down, the battery charge and discharge performance will be affected. But the temperature is too high, more than 45, will destroy the chemical balance within the battery, leading to side effects

What are the overcharging control methods?
In order to prevent the battery overcharge, the need to control the end of the charge, when the battery is full, there will be some special information available to determine whether the end of the charge. There are six ways to prevent the battery from overcharging:
1, the peak voltage control: by detecting the peak voltage of the battery to determine the end of the charge;
2, dT / dt control: by detecting the peak temperature of the battery rate of change to determine the end of the charge;
3, T control: the battery is fully charged when the temperature and ambient temperature difference will reach the maximum;
4, -V control: When the battery is fully charged to reach a peak voltage, the voltage will drop a certain value
5, timing control: by setting a certain charging time to control the charging end, the general set to fill the nominal capacity of 130% of the time required to control;
6, TCO control: consider the safety and characteristics of the battery should avoid high temperature (except high-temperature battery) charge, so when the battery temperature should be 60 to stop charging.