1. Voltage measurement method
That is, the battery power is obtained by simply monitoring the battery voltage. Advantages of this method: simplicity Disadvantages: imprecise, the precision of the power measurement is only greater than 20%. Especially when the battery charge is less than 50%, the phone power calculation will become very inaccurate. Battery protection by this method is therefore very limited.
2. Battery modeling method
This method involves creating a data table based on the battery discharge curve. The data table will show the power values at different voltages. Advantages: More accurate than the voltage test method. Disadvantages: Obtaining an accurate data sheet is not simple because the relationship between voltage and power also involves factors such as battery temperature, self-discharge and agingis lying.
Early developments of lithium batteries
Lithium batteries were first used in pacemakers. Lithium batteries have the advantages of extremely low self-discharge rate and gentle discharge voltage, allowing pacemakers implanted in the human body to work for a long time without recharging. Lithium batteries typically have a voltage rating above 3.0 volts and are best suited for use as an integrated circuit power supply. Manganese dioxide batteries are widely used in calculators, digital cameras and watches.
In order to develop more efficient varieties, various materials were researched to create unprecedented products.
In 1992, Sony successfully developed lithium-ion batteries. Its practicality has significantly reduced the weight and volume of portable electronic devices.tables such as cell phones, laptops and calculators.
The battery capacity of my mobile phone is 5800 MAH. Is the capacity considered large? How long can I listen to music on a full charge?
Lithium battery life test standard: GB/T 18287-2013, CALL user name for details
According to the national standard for lithium batteries: GB/T18287-2000, test items for lithium batteries, including appearance, discharge performance, high and low temperature performance, charge retention capacity, environmental adaptability of heat resistance, vibration resistance, collision resistance and free fall safety performance of overload protection, overcurrent protection and short circuit protection; circuit protection; pesafety performance in resistance to violent shock, thermal shock, overload, short-circuit storage performance, etc. The following focuses on testing conditions and standards for discharge performance, high and low temperature performance, service life, and protection against overcharge, overdischarge, and short circuit.
1. In terms of discharge performance testing, the standard requires charging to the specified charge-discharge rate and discharging to the final voltage under the conditions of (20±5)℃, and the discharging time should not be less than the specified value.
2. High temperature and low temperature performance are tested under the conditions of (55 ± 2) ℃ and (-20 ± 2) ℃ [for lithium ion polymer batteries, it is (-10 ± 2) ℃], After the experiment, remove the battery and leave it for 2 hours at an ambient temperature of (20 ± 5) °C. The battery does notmust show no deformation or explosion.
3. The lifespan requirement is to charge and discharge at 1C5A at an ambient temperature of (20±5)°C. until the final voltage, leave it for 0.5-1 hour, then pass to the next charge and discharge cycle. Until two consecutive discharge times are less than 36 minutes, the service life is considered to be over. Battery life should not be affected. less than 300 times.
4. For protection against overcharge, overdischarge and short circuit, it is necessary that the battery does not explode, ignite, smoke or leak under specified operating conditions.
Large capacity battery In the era of smart phones, they are becoming more and more popular. However, yesterday, staff from the Nanjing Inspection and Quarantine Bureau told reporters that during the inspection and supervision of mobile phone batteries, they had found that according to relevant mandatory standards, some large capacity lithium batteries were damaged by thermal shock and heavy objects. If the safety features fail the test, large-capacity cell phone batteries still pose certain safety risks. It is understood that as lithium batteries for smartphones become larger and smaller in volume, the conversion of electrochemical and chemical energy into thermal energy is the main reason for the safety risks of lithium batteries. , particularly during “thermal shock” tests. When the test temperature reaches a certain temperature, the separation membrane will melt and shrink, resulting in a short circuit phenomenon and producing unexpected energy conversion. Under the test conditions stipulated in the mandatory standardsTories, the larger the capacity of a lithium battery, the higher the likelihood of internal short circuits, increasing the risk of safety issues. The Nanjing Inspection and Quarantine Bureau reminds citizens, especially smartphone consumers, that when choosing mobile phone batteries, they should reduce their blind search for large-capacity lithium batteries and try to choose mature products from classic brands. At the same time, avoid using your smartphone in environments with excessively high temperatures and in environments where you may encounter impacts and collisions with heavy objects to avoid accidents!