What is the difference between 18650 lithium battery and soft pack lithium battery.

What is the difference between 18650 lithium battery and soft pack lithium battery.

1. The difference in electrolyte between 18650 lithium-ion battery and soft pack lithium-ion battery

Although 18650 lithium-ion batteries and soft pack lithium-ion batteries have different shapes and internal structures, their principles are basically the same. Both types of batteries have a positive electrode, a negative electrode, and an electrolyte. The positive electrode material is generally lithium cobalt oxide, lithium nickel cobalt manganese oxide (ternary material), lithium iron phosphate, or lithium manganese oxide, while the negative electrode material is generally graphite. The electrolyte is lithium hexafluorophosphate solution.

As the two mainstream lithium-ion batteries in the current market, 18650 lithium-ion batteries and lithium polymer soft pack batteries are distinguished by their shell packaging materials. 18650 lithium-ion batteries are generally enclosed in a steel shell (18 represents a diameter of 18mm, 65 represents a length of 65mm, 0 represents a cylindrical battery), and the structure of the internal electrode plates and separators is wound. The outer packaging of lithium polymer soft pack batteries uses aluminum-plastic film, and the internal electrode sheets and separators are stacked layer by layer.

The important difference between the 18650 lithium-ion battery and the soft pack lithium-ion battery lies in the shape of the electrolyte in the battery's internal material: the electrolyte in the lithium polymer soft pack battery is polymer, generally gel or solid, while the electrolyte in the 18650 lithium-ion battery is generally liquid.

2. The advantages, disadvantages, and application fields of 8650 lithium-ion batteries and soft pack lithium-ion batteries are different

18650 lithium-ion batteries and lithium polymer soft pack batteries each have their own advantages and disadvantages. At present, the production automation level of 18650 lithium-ion batteries is high, and the consistency and safety of the batteries have reached a high level. In addition, the small size and light weight of the batteries themselves give them unique advantages in the modularity and standardization of system development. Many people believe that using 18650 lithium-ion batteries as the power source for new energy electric vehicles is a better choice at this stage.

Compared with 18650 lithium-ion batteries, lithium polymer soft pack batteries have higher single cell capacity and advantages such as thinning, arbitrary area, and arbitrary shape (ultra-thin batteries such as 0.33mm and 0.50mm can be produced). However, their important disadvantages are poor consistency and mechanical strength. Based on the characteristics of lithium polymer pouch batteries, lithium polymer pouch batteries are increasingly being used in fields such as mobile phones, laptops, and power banks. However, due to the poor conductivity and high internal resistance of colloidal (or solid) electrolytes, lithium polymer soft pack batteries are rarely used in electric vehicles.