1: discharge current

The size of discharge current and its influence on lithium battery. Different lithium batteries support different discharge rate. Generally, there are cells with discharge rate of 0.2C, 0.5c1c3c5c10c10c20c, etc. under different discharge rate, the capacity retention rate of the same cell is different. The larger the discharge rate is, the less the capacity will be released. Therefore, when selecting lithium battery, pay attention to the selection of appropriate The battery with the load working current. Of course, the larger the discharge rate, the less the nominal capacity of the battery itself, the lower the energy density, the better the current passing ability and the smaller the internal resistance of the battery. The same type of battery, long-term high rate discharge, also has an impact on cycle life, cycle life will decay faster.

2: charging current

What is the effect of charging current on lithium battery? Generally, the recommended charging rate of lithium battery is 0.2C. For example, for a 10Ah lithium battery, 2A charging current is generally used, and 0.5c charging is also widely used. Of course, there are many quick charging schemes on the market, 1c-2c scheme, 30 minutes full, 40 minutes full. The charging current has a great impact on the battery capacity retention rate, cycle life and safety. The more charging current is, the more Large, the smaller the actual charging capacity, the more severe the cycle life decay, and the lower the safety. As we all know, most of the lithium battery combustion accidents happen during the battery charging process.

However, the charging time directly affects the customer's experience. What should we do? We have to choose the most suitable one for our specific projects and application scenarios.

3: working temperature

Generally, the charging temperature of conventional lithium battery is 0 ~ 45 ℃, and the discharge temperature is - 20 ~ 60 ℃. At low temperature, the lithium ion is not active enough, the temperature is too high, and the lithium ion is too active again, so the lithium battery generally has a clear working temperature range. The lithium battery has high energy density, more energy storage, but it is also very fragile. How to use it strictly according to the instructions of the manufacturer? In the low temperature state, charging will lead to lithium evolution. There is metal lithium precipitation on the anode surface of the battery, forming dendrite, piercing the diaphragm between anode and cathode, causing short circuit inside the cell, causing heating, combustion, and even explosion. With the innovation of technology and the improvement of electrolyte, now the special lithium battery can be charged at - 20-45 degrees and discharged at - 50-60 degrees. Of course, the cost will be higher.

The influence of temperature on the discharge performance of the battery is that the lower the working temperature is, the less the discharged capacity will be when tested with the same current. The capacity retention rate of lithium batteries of different materials is different under the same temperature. The general capacity retention rate of ternary lithium batteries is about 80% left and right, and that of lithium iron phosphate is about 60%.

At present, the capacity retention rate of - 40 ℃ 0.5c for low-temperature lithium battery is about 80%. The low-temperature and high-power battery can achieve 1c3c low-temperature discharge. How does it behave at high temperature? Within the maximum temperature specified by the manufacturer, it has little impact on the capacity, but long-term high-temperature operation also has an impact on the cycle life of the battery. There are many so-called high-temperature cells on the market. Yunsheng electronic technology has basically tested them, all of them are so-called, stealing the concept. You need to know that lithium battery can work at high temperature in a short period of time, and there is no abnormality on the surface. Long term test is easy to bulge, leakage, fire and so on.

4: working condition

Different working conditions actually have a great impact on lithium battery, such as the digital products we use everyday, which are charged one day, charged at night, and illuminated during the day. This is deep charging and deep discharging, like our solar photovoltaic energy storage, which is discharged a little, and then charged back immediately. This is the case of potential charging and potential discharging. In the first case, the life of the lithium battery is greatly affected, and the cycle life is severely attenuated.