Factors affecting the internal resistance of 18650 lithium batteries.

Factors affecting the internal resistance of 18650 lithium batteries.

2.1. electrode material

The type, particle size, purity, and other factors of electrode materials can all affect the internal resistance of batteries. For example, using highly conductive electrode materials can reduce the internal resistance of batteries; The smaller the particle size and higher the purity of the material, the larger the contact area between the electrode and the electrolyte, the lower the resistance to electron conduction and ion diffusion, and the lower the internal resistance.

2.2. electrolyte

The ionic conductivity, viscosity, and other properties of the electrolyte have a significant impact on internal resistance. Electrolytes with high ionic conductivity can facilitate rapid migration of lithium ions between electrodes, thereby reducing internal resistance; Low viscosity electrolytes are beneficial for the diffusion of lithium ions and can also reduce internal resistance.

2.3. Cell structure

Reasonable battery structure design can optimize the electronic conduction path and ion diffusion channel, reduce internal resistance, such as using thin separators, appropriate electrode spacing, and good electrode coatings, all of which can reduce the internal resistance of the battery. In addition, the assembly process of batteries can also affect internal resistance. Accurate assembly can ensure good contact between electrodes and electrolyte, reducing contact resistance.

2.4. temperature

The temperature has a significant impact on the internal resistance of 18650 lithium batteries. Generally, as the temperature increases, the diffusion rate of ions inside the battery accelerates, the ion conductivity of the electrolyte increases, and the electronic conductivity also increases, resulting in a decrease in internal resistance. On the contrary, in low-temperature environments, both ion diffusion and electron conduction are hindered, resulting in an increase in internal resistance. Therefore, at different operating temperatures, it is necessary to appropriately correct and compensate for the internal resistance of the battery.

As the core unit in the field of power batteries, the quality of 18650 lithium batteries directly affects the operational efficiency of electric tools, energy storage equipment, and new energy vehicles. According to the "White Paper on the Development of Lithium ion Battery Industry" newly released by the Ministry of Industry and Information Technology, the annual production of 18650 batteries in China has exceeded 5 billion units, but the market qualification rate has only maintained a level of 78.6%. Faced with such a complex market environment, "Which is the best 18650 lithium battery?" and "18650 lithium battery internal resistance standards" have become key considerations for procurement decisions.