What Is A Soft Pack Lithium Iron Phosphate (LiFePO4) Battery

A soft pack lithium iron phosphate (short for: LiFePO4/ LFP/ LiFe) battery refers to a lithium-ion battery with lithium iron phosphate as the positive electrode material. Due to its high safety, long cycle life, and relatively low cost, LFP batteries are increasingly being used in power and energy storage applications.

There are three main forms of lithium iron phosphate batteries based on their packaging: cylindrical cells, soft pack cells (also Pouch cells), and aluminum shell cells. Among them, aluminum-shell LiFe batteries have seen a significant increase in installation volume in recent years and have taken a dominant position among the three types of batteries.

However, an increasing number of manufacturers have started adopting the aluminum-plastic film soft pack LiFe cells process. For example, in 2021, BYD achieved great success in the market with its blade battery. In their DMI hybrid models, BYD began using soft pack lithium iron phosphate battery modules (referred to as "small blade cells") with aluminum-plastic film packaging for the LiFePO4 cells. So, what exactly is a soft pack lithium iron phosphate battery?

What is a Pouch Cell lithium iron phosphate battery?

A soft pack lithium iron phosphate battery is essentially a liquid lithium-ion battery encased in a layer of polymer shell. It is packaged using an aluminum-plastic film and, in the event of a safety hazard, the soft pack battery may inflate or rupture. Soft pack lithium iron phosphate batteries are also known as polymer lithium batteries.

How does a soft pack LFP battery differ from cylindrical and aluminum shell LFP?

Capacity

Soft pack LiFePO4 batteries generally have a capacity that is 10% to 15% higher than that of an equivalently sized steel shell battery or 5% to 10% higher than that of an aluminum shell battery. While the difference in capacity between soft pack and hard pack LFP batteries is not significant, there is still some variation. In applications that require higher capacity, the use of soft pack Li-ions is preferred over hard pack oens.

Battery Shape

Since the internal cells of soft pack lithium iron phosphate batteries are in a liquid state, they can be manufactured in various shapes. This characteristic provides a significant advantage over hard pack lithium iron phosphate batteries in fields that have specific shape requirements for the batteries.

Soft-pack LFP batteries have advantages in terms of weight, capacity, and shape compared to hard pack LiFePO4 batteries. However, the current market availability of soft pack LiFePO4 battery cell models is relatively limited, and the development of new models is also costly. Therefore, the market demand that can be met by pouch cell LiFePO4 is still relatively small. Nevertheless, with the recent market developments, the demand for soft pack LiFePO4 batteries is growing, and their application areas continue to expand.

Battery Weight

Soft pack lithium iron phosphate batteries are approximately 40% lighter than steel-shell LiFe batteries and 20% lighter than aluminum shell ones of the same capacity. The weight reduction in soft pack LiFePO4 cells is primarily due to the lighter weight of their outer shell.

The above provides an introduction to soft-pack LiFe batteries. As a leading lithium battery manufacturer with strong comprehensive capabilities, Grepow Battery adopts mostly automated production equipment, including advanced imported manufacturing equipment. This ensures high precision in the production of soft pack lithium iron phosphate batteries and significantly reduces the defect rate associated with manual operations, resulting in higher consistency of Pouch cell LiFePO4. With a skilled workforce of over 3000 battery manufacturing professionals and 200+ experienced lithium and nickel-metal hydride battery research and development engineers, Grepow Battery can provide customers with high-quality custom production services for soft-pack lithium-ion batteries.