What is the difference between square cells and soft pack cells?

Introduction:

The demand for increasing battery capacity has led to the popularization of square cells and soft pack cells. Although these two types of cells have many similarities, they also have obvious characteristics that distinguish them. Square cells and soft pack cells are the two most popular types of cells used to create battery packs. Their shape allows them to stack well when creating powerful battery packs. This article will provide you with a detailed comparison between square cells and soft pack cells, enabling you to choose the cells required for your project or appliance.

What is a square lithium-ion battery cell:

A square lithium-ion battery is a type of battery with square cells or a stack of square cells. A square cell refers to a cell that is wrapped in a shell made of steel or aluminum. Square lithium-ion cells are more stable than other cell types.

What is a soft-pack lithium-ion battery cell?

Soft-pack lithium-ion cells are made by covering liquid or mild solid lithium ions with aluminum plastic. Soft-pack lithium cells use conductive foil instead of metal cylinders as electrodes. There is no standard shape or size for soft pack cells. Therefore, each manufacturer of soft pack cells can design their own.

What is the difference between a square cell and a soft pack cell?

The similarities between square cells and soft pack cells are much greater than their differences. However, there are some differences in functionality and design that may make people prefer one of them. The core is that when comparing square cells with soft pack cells, which one is better depends on the application field and available budget.

Shape:

Both square cells and soft pack cells are rectangular. However, the shape of the soft bag is more flexible and can be customized according to application requirements.

Packaging materials:

The square cell uses a rigid hard shell made of aluminum or steel, while the soft core uses conductive foil (polymer-coated aluminum foil shell). The outer shell of the soft pack battery gives it flexibility.

Size:

The size of square cells may be slightly larger. However, due to their design being subject to the manufacturer's requirements, they can all be made larger or smaller as needed.

Weight:

Compared to square cells, soft pack cells are usually lighter in weight. This is because the shell used in the square cell makes it even larger.

Cell voltage and capacity:

Due to the flexibility of their design, the capacity of these cells can be increased. However, square cells have a larger capacity because they can stack better in their rigid shells compared to soft pack cells.

On the other hand, do larger cells have more voltage? Soft pack cells are relatively thin, but compared to square cells, they can handle more voltage because they can handle explosive or high voltage levels in a short period of time.

Durability:

Soft pack cells are more susceptible to damage from high temperature and humidity. This may have adverse effects on their lifespan. In this regard, square cells are better than soft pack cells. However, if the battery cell is also in a poor state, the probability of explosion and fire of the soft pack battery cell will be much smaller than that of the square type battery cell, and they will only experience bulging.

Cost:

The price of battery cells depends to a certain extent on the standardization of production and the influence of factors such as raw materials for battery cells. However, compared to square cells, the manufacturing cost of soft pack cells is higher due to the overall quantity and cost of materials. In addition, compared to square cells, the manufacturing process of soft pack cells is more complex. Overall, the cost of soft-pack cells is relatively high.

Performance:

Soft pack battery cells, due to their lightweight, reliable, flexibility, and small size, are the preferred choice for devices such as smartphones, drones, and ultra-thin laptops. Compared to square cells, they are also safer because they are less likely to explode. On the other hand, square cells are more suitable for ESS (energy storage systems) and electric vehicles. Square cells are more susceptible to issues related to thermal management. Although the performance of these cells is limited by their location of use, soft pack cells perform better in each application area.

Application of square cells and soft pack cells:

The application of square cells is almost similar to that of soft pack cells. However, in some cases, users prefer square cells over soft pack cells, and vice versa. Their application is a key figure in comparing square cells with soft pack cells.

Square cells were introduced in the early 1990s to meet the demand for smaller-sized cells. However, this does not mean that there is no larger size; These batteries do not have a standard design, and manufacturers design them according to their application areas.

The application range of square cells:

Smaller-sized square cells are used for mobile phones, tablets, and laptops, with a rated power range of 800mAh to 4000mAh.

Larger designed square cells are used for energy storage systems, such as power wall batteries and the power systems of electric and hybrid vehicles.

The launch of the small soft-pack battery cell in 1995 was a complete revolution. They are both lightweight and flexible, making them highly popular in battery packs. Among all battery cells, soft-pack batteries are the most effective in space utilization. Soft pack cells are the standard for consumer applications.

Application fields of soft pack cells:

Smaller-sized soft pack cells are used for applications that require high currents, such as drones, jump starters, and other portable hobby small tools.

Larger soft-pack batteries are used for racing motorcycles, racing cars, and military equipment that require strong, magnetic, or explosive power. Although in these application scenarios, cylindrical and square cells are more commonly used. Larger cells are also used for ESS (energy storage system).

Advantages and disadvantages of square cells and soft pack cells:

Advantages of flexible battery cells:

They have a long lifespan. A series of tests conducted on these cells found that after 4000 charging cycles, the DOD remained above 80%.

In the same physical space, they provide better energy storage than cylindrical cells.

Small soft-pack cells are safer than other types of cells. Even if they have internal problems and swelling, the soft-pack battery cells can handle pressure.

Disadvantages of flexible battery cells:

Compared to cylindrical cells, soft pack cells have a relatively poor mechanical load-bearing capacity

The manufacturing cost of flexible battery cells is higher than that of traditional battery cells.

They are more prone to damage.

Due to the different designs of soft pack cells, they are more prone to leakage.

Advantages of square cells:

Compared to cylindrical cells, square cells have more energy per cell.

Compared to traditional battery cell units, their cycle life is longer

Compared to cylindrical cells, square cells have lower manufacturing costs.

Disadvantages of square cells:

The heavy shell (steel or aluminum) of a square cell has a limiting effect on the energy density of the battery pack.

The manufacturing process of square cells is very complex

Relatively speaking, the safety is relatively low, and in larger battery packs, attention should be paid to heat dissipation.

Which is better, a square cell or a soft pack cell

When comparing square and flexible battery cells, there are several factors to consider, which one is better. It's great to take a look at the application field; In some cases, a softcore may be better than a square core, and vice versa. Nevertheless, it is important to note that the use of these cells is almost identical. However, from a manufacturing perspective, the manufacturing of square cells is more complex than that of soft pack cells, which means that soft pack cells are better in this situation.

Conclusion:

The debate between square and flexible battery cells ultimately boils down to the issue of application fields. In the above article, we have emphasized the situation and reasons why soft pack cells may be more popular. For example, square cells are more explosive and magnetic than soft pack cells, making them the preferred choice in racing. On the other hand, soft-pack batteries are safer, lighter, and have a longer cycle life than square-type batteries, making them more popular in mobile and laptop batteries. Compared with cylindrical cells, square and soft-packaged cells have improved efficiency and effectiveness, making them highly popular. Your project type will determine the type of battery cell you will choose.