When we evaluate the performance of lithium batteries, we often use a metric called C-rate. What does this number represent? Is a larger number better or a smaller number better? I will explain what C-rate is and how it affects the battery life.
C-rate is a method of measuring the charging and discharging speed of a battery. Simply put, if a battery can be fully charged in 1 hour, its charging rate is 1C; if it takes 2 hours to charge, the rate is 0.5C; and if it takes 4 hours to charge, the rate is 0.25C. The larger the number, the faster the charging speed. The same applies to discharging, with a larger number indicating a faster discharging speed. We can use the following formula to calculate C-rate:
C-rate = charging/discharging current ÷ rated capacity.
If not specified, the charging and discharging rates of a battery are generally the same. However, in certain specific applications that require high instantaneous power output from the battery, the discharging rate may be higher than the charging rate. For example, the discharging rate for electric vehicle batteries is typically 3-5C, while the charging rate is 0.1-0.5C; energy storage battery discharging rates are generally above 1C, with charging rates of 0.5-1C; and some industrial equipment battery discharging rates can exceed 5C, with charging rates below 0.5C.
Taking the example of a Sycain 100AH lithium battery, its charging and discharging rate is consistent at 0.5C, meaning it takes 2 hours for the battery to fully charge and discharge.
However, in practical use, in order to extend the battery life, lithium batteries are generally not charged at such high C-rates. According to the formula mentioned above, a larger C-rate results in a larger current. Charging the battery with a large current can cause it to heat up quickly, accelerating battery aging. Therefore, lithium batteries are usually configured with chargers that operate at 0.2C. For a 100AH lithium battery, the standard charging current of the charger is 20A, and the normal charging time is 5 hours.
However, with the maturity of BMS technology and intelligent temperature control technology, fast charging technology is solving the problem of heat damage to the battery. The next generation of Sycain batteries has already adopted fast charging technology, significantly reducing charging time, and we believe it will be available to everyone soon.
If you need to purchase lithium batteries, please visit our website: www.sycaintech.com.
Published on: Dec 28, 2023
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