18650 lithium battery pack with large internal resistance or small internal resistance?

Is the internal resistance of 18650 battery pack large or small? Resistance indicates the resistance of a circuit element to current transmission. The unit is Ohm. The internal resistance of 18650 battery pack is related to the capacity and type of battery. Generally speaking, the larger the capacity, the smaller the internal resistance. For batteries with the same capacity, the internal resistance of the multiple type is smaller than that of the capacity type. The internal resistance of a typical lithium battery pack is only a few milliohms.

Is the internal resistance of 18650 battery pack large or small?

Inside the lithium battery, lithium ions move from one pole to the other, and the factors that hinder the movement of ions together form the internal resistance of the lithium battery. The main part includes the physical internal resistance of the conductive part; Inherent impedance of electrochemical substances such as motor materials, diaphragms and electrolytes; The resistance to the movement of lithium ion temporarily increased when there is current in the battery; These three parts together constitute the main body of internal resistance.

The internal resistance of 18650 battery pack is the most sensitive to temperature. The internal resistance value can change greatly at different temperatures. One of the important reasons for the degradation of battery performance at low temperature is the excessive internal resistance of the battery at low temperature. 18650 lithium battery pack is a power supply. From the outside, the smaller the internal resistance, the better. Especially in power applications, small internal resistance is a necessary condition.

The larger the capacity, the larger the area, and the smaller the resistance the current passes through. The internal resistance of lithium battery pack must be as small as possible. The smaller the internal resistance, the less energy is wasted for the battery, and it is helpful for the heat generation and magnification of the battery.

In recent years, new energy vehicles have higher and higher requirements for the high rate charge and discharge performance of power batteries, and the internal resistance is an important factor affecting the battery power performance and discharge efficiency. With the use of 18650 lithium battery pack, the battery performance has been declining, mainly manifested in capacity attenuation, internal resistance increase, power decline, etc. the change of battery internal resistance is affected by temperature, discharge depth and other service conditions.

Internal resistance is an important parameter to measure the power performance and evaluate the battery life of lithium batteries. The greater the internal resistance, the worse the rate performance of the battery, and the faster the increase in storage and recycling. The internal resistance is related to battery structure, battery material characteristics and manufacturing process, and changes with the change of ambient temperature and state of charge. Therefore, the development of low internal resistance battery is the key to improve the battery power performance. At the same time, it is of great practical significance to grasp the change law of battery internal resistance for battery life prediction.

18650 lithium battery pack cannot discharge with high current due to its high internal resistance. The lower the theoretical internal resistance, the better. The internal resistance is directly related to the capacity. General lithium batteries assume an internal resistance of about 30 to 80 ohm at 1 ampere hour, while good power lithium batteries can be less than 15 ohm.

The internal resistance of lithium battery is high. When discharging, the battery heat should be higher. In short, the smaller the internal resistance of lithium battery, the better.