We should choose 18650 Lithium ion battery pack with large internal resistance or small?

In a lithium-ion battery, the lithium ions move from one pole to another, and the factors that hinder the movement of the ions together form the internal resistance of the lithium-ion battery.  The important part includes the physical resistance of conductive parts;  Intrinsic impedance of electrochemical materials such as motor materials, diaphragms and electrolytes;  There is a temporary increase in the battery internal current through the movement of lithium ion obstruction;  These three parts together constitute the main body of internal resistance.  

The internal resistance of 18650 lithium ion battery pack is most sensitive to temperature, and 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 battery at low temperature.  18650 lithium ion battery pack as a power supply, from the external point of view, the internal resistance is certainly as small as possible.  Especially in power applications, small internal resistance is a necessary condition.  

The larger the capacity, the smaller the resistance the current passes through.  The internal resistance of a lithium-ion battery pack should be as low as possible.  The smaller the internal resistance is, the less energy is wasted on the battery, and the heat production and multiplier of the battery are helpful.  

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

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

18650 lithium ion battery pack high internal resistance can not be large current discharge, theoretical internal resistance is the lower the better, internal resistance and capacity is directly related.  A typical lithium-ion battery assumes an internal resistance of about 30 to 80 ohms at 1 amh, while a good power lithium battery can be below 15 ohms.  

Lithium ion battery internal resistance is high, discharge, battery heating is higher, in short: lithium ion battery internal resistance is smaller, the better.