Choose high-quality and high safety 18650 lithium-ion batteries?
18650 lithium batteries are mostly used as laptop batteries due to their large capacity per unit density. In addition, 18650 has excellent stability performance during operation and is widely used in various electronic fields, such as high-end high-power flashlights, portable power supplies, wireless data transmitters, electric thermal clothing, shoes, portable instruments and meters, portable lighting equipment, portable printers, industrial instruments, medical instruments, etc.
So how to choose high-quality 18650 lithium-ion batteries? Choose the most suitable 18650 lithium battery for our electrical equipment, such as the appropriate brand, voltage, capacity, continuous discharge rate, battery life, etc. The most important thing is to choose a battery with high safety. Below, we will provide a detailed introduction one by one:
1. Brand
Regarding brands, internationally renowned brands such as Sanyo, Samsung, SONY, LG, etc. are currently more reliable. Sanyo and LG focus on conventional applications, mainly in strong light flashlights, power banks, laptop batteries, etc. SONY specializes in high power and current. Taking VTC4 as an example, the discharge current can reach 30A, which can easily handle electronic cigarettes, toys, etc.
2. Nominal capacity
The nominal capacity of an 18650 battery is related to its endurance, measured in "mAh". The higher the capacity, the stronger the endurance. For example, a 2800mAh battery can discharge continuously for 2 hours with a current of 1.4A.
3. Continuous discharge current (CDR)
The continuous discharge capacity is represented by the C number, and the continuous discharge current=the continuous discharge capacity C number multiplied by the capacity. For example, if the capacity of an 18650 battery is 2800mAh and its continuous discharge capacity is 0.5C, then the continuous discharge current is 1.4A. If the discharge exceeds 1.4A for a long time, it will seriously affect the battery life and may pose risks such as overheating, combustion, and explosion.
5. Internal resistance
Internal resistance is the resistance of the battery itself. The smaller the internal resistance, the less it consumes and the stronger its discharge capacity. This parameter is usually written on the battery introduction page. When purchasing, it is also important to pay attention and try not to buy batteries with a resistance of more than 100m Ω. When using multiple 18650 batteries in series, it is necessary to buy batteries of the same brand and model, otherwise batteries with high internal resistance and low capacity will become a weakness.
6. Temperature
Temperature is a significant factor affecting the lifespan of 18650 lithium batteries. The higher the temperature, the faster the battery ages, and the greater the damage to the battery's interior.
7. Sharp pointed and flat headed
There are two types of 18650 lithium batteries: flat head and pointed head. The positive electrode on the left side with a protrusion is pointed head, while the positive electrode on the right side without a protrusion is flat head. In general, I recommend purchasing pointed batteries to ensure compatibility with a wider range of devices and applications. Usually, the positive and negative poles of flashlights are designed with springs, which can be extended and retracted. Both pointed and flat batteries can be used. But if a flat head battery is to be used in series, the positive pole of the flat head cannot contact the negative pole of another battery.
