What is a soft pack lithium battery?

As a type of power battery, the application and penetration of soft pack batteries in the field of batteries are accelerating with their own advantages. Based on the development of soft pack batteries in recent years, many battery companies have begun to actively layout in this field. So what is a soft pack battery and what are its advantages?

The so-called soft pack battery is a term used to refer to two types of hard shell batteries, cylindrical and square. Its internal composition (positive electrode, negative electrode, separator, electrolyte) is not significantly different from square and cylindrical lithium batteries. The biggest difference is that soft pack batteries use aluminum-plastic composite film as the outer shell. In the event of safety hazards, soft pack batteries will only burst and crack at most. Square and cylindrical batteries use metal materials as their shells.

For soft pack batteries, in terms of structure, their own safety performance is good, and in terms of volume, their advantages such as light weight, large capacity, small internal resistance, and flexible design are gradually showing their advantages and status. Generally speaking, soft pack batteries have the following advantages:

1. Good safety: The soft pack battery is structurally packaged with aluminum-plastic film. In the event of thermal management loss of control or puncture, the soft pack will provide buffer space for the battery cell, causing bulging deformation and ultimately catching fire or smoking, but will not explode.

2. Lightweight and high energy density: Soft pack batteries are 40% lighter than steel shell batteries of the same capacity and 20% lighter than aluminum shell batteries, so they usually have a higher energy density. Currently, most battery companies in China that have exceeded the energy density threshold of 300Wh/kg use soft pack batteries.

3. Good electrochemical performance and long lifespan: The internal resistance of the soft pack battery is small, which can greatly reduce the battery's self consumption; In addition, the cycle life of the soft pack battery is longer.

4. The thickness is small and can be made thinner. Ordinary liquid lithium batteries use the method of customizing the shell first and then plugging positive and negative electrode materials. When the thickness is below 3.6mm, there is a technical bottleneck. However, lithium iron phosphate and lithium manganese battery cells do not have this problem, and the thickness can be below 2.5mm.

5. The capacity of lithium iron phosphate and lithium manganese oxide flexible packaging lithium batteries with similar specifications is 10-15% higher than that of steel shell batteries and 5-10% higher than that of aluminum shell batteries.
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