Several factors affecting the performance of lithium batteries

What conditions affect the performance of lithium batteries? Next, Dongguan Ruisai Energy Technology will discuss with you several factors that affect lithium batteries. Welcome to our company's official website for discussion and leave a message.

1: Discharge current

The size of discharge current has an impact on lithium batteries. Different lithium batteries support different discharge rates, usually with discharge rates of 0.2C, 0.5C, 1C, 3C, 5C, 10C, and 20C. For the same type of battery, the capacity retention rate varies at different discharge rates. The larger the discharge rate, the less capacity can be discharged. Therefore, when choosing a lithium battery, it is important to choose a battery that is suitable for the working current of the load. Of course, the higher the discharge rate of a battery, the lower its nominal capacity, the lower its energy density, the better the internal electrode ears and welding position, the better the current passing ability, and the lower the internal resistance of the battery. The same type of battery, long-term high rate discharge, also has an impact on the cycle life, and the cycle life will decay faster.

2: Charging current

What is the impact of charging current on lithium batteries? The recommended charging rate for general lithium batteries is 0.2C. For example, a 10Ah lithium battery usually uses a charging current of 2A, and there are also many applications of 0.5C charging. Of course, there are many fast charging schemes on the market, such as the 1C-2C scheme, which can be fully charged in 30 minutes or 40 minutes. The charging current has a significant impact on the capacity retention, cycle life, and safety of the battery. The larger the charging current, the smaller the actual capacity charged, the more severe the cycle life decay, and the safety will also decrease. As we all know, most lithium battery combustion accidents occur during the charging process of the battery.

However, the length of charging time directly affects the customer experience. What should we do? We still need to choose the most suitable project and application scenario for our specific project.

3: Working temperature

Generally, conventional lithium batteries have a charging temperature of 0-45 degrees and a discharging temperature of -20~60 degrees. At low temperatures, lithium ions are not active enough, and when the temperature is too high, lithium ions become too active. Therefore, lithium batteries generally have a clear working temperature range. Lithium batteries have high energy density and store a lot of energy, but they are also very fragile. How can they be used strictly according to the manufacturer's instructions. At low temperatures, charging can cause lithium deposition. Metal lithium precipitates on the anode surface of the battery, forming dendrites that pierce the separator between the anode and cathode, causing internal short circuits in the battery cell, resulting in heating, combustion, and even explosion. With the innovation of technology and the improvement of electrolytes, special lithium batteries can now be charged at -20 ° C to 45 ° C and discharged at -50 ° C to 60 ° C. Of course, the cost will be relatively high.

The influence of temperature on battery discharge performance: the lower the operating temperature, the less capacity can be discharged when tested with the same current. Different materials of lithium batteries have different capacity retention rates at the same temperature, around -20 degrees. Ternary lithium batteries generally have a capacity retention rate of about 80%, while lithium iron phosphate batteries generally have a capacity retention rate of about 60%.

Nowadays, low-temperature lithium batteries have a capacity retention rate of about 80% at -40 ° C and 0.5C, and those with low temperature and high rate can achieve 1C and 3C low-temperature discharge. How does it perform at high temperatures? Within the maximum temperature specified by the manufacturer, there is not much impact on the capacity, but long-term high-temperature operation also has an impact on the battery's cycle life. Many battery cells on the market that claim to be high-temperature have been tested by Yunsheng Electronic Technology, and they are all claimed to be interchangeable concepts. It should be noted that lithium batteries can also work at high temperatures for a short period of time, and there is no apparent abnormality on the surface. Long term testing can easily lead to swelling, leakage, and fire.

4: Working conditions

The actual impact of different working conditions on lithium batteries is significant. For example, the digital products we use in daily life are charged once a day, fully charged at night, and emit light during the day, which is called deep charging and deep discharging. For example, our solar photovoltaic energy storage system releases a little electricity and immediately charges it back, which is called latent charging and discharge. The first scenario has a significant impact on the lifespan of lithium batteries, with a significant decrease in cycle life.

Summary: Today we will first focus on a few key points. In fact, there are many factors that affect the performance of lithium batteries, such as our usage habits, etc. Welcome everyone to leave a message for discussion and exchange. Thank you!