Soft-pack polymer lithium batteries are essentially battery cells that use aluminum-plastic packaging film as the packaging material. It's worth noting that lithium battery packaging is divided into two types: soft-pack cells and metal-cased cells. The difference usually refers to the material of the battery casing; soft-pack batteries are softer than aluminum-cased lithium batteries and are easily deformed by hand. So today, let's look at the characteristics and differences between soft-pack and hard-pack lithium batteries.
What is a pouch polymer lithium battery?
Soft-pack polymer lithium batteries are actually subdivided into soft-pack lithium batteries and polymer lithium batteries. The difference is that polymer lithium batteries contain a gel-like electrolyte and feel harder to the touch; soft-pack lithium batteries contain a liquid electrolyte and feel slightly softer. In fact, soft-pack lithium batteries were invented as a result of the immature manufacturing process of polymer lithium batteries, after weighing the pros and cons. Considering their relatively lower cost and stable performance parameters under basic usage conditions, they have captured a large share of the 3C digital product battery market.
The new batch of polymer lithium-ion batteries achieves thinness (ATL batteries can be as thin as 0.5 mm, equivalent to the thickness of a credit card), fixed area, and random shape, greatly improving the operational flexibility of battery product appearance design. This allows them to be manufactured into batteries of any shape and capacity to meet product requirements, bringing a high degree of design flexibility and adaptability to power solutions for application equipment service providers, in order to maximize the optimization of their product performance parameters.
Characteristics and differences between soft-pack and hard-pack lithium batteries:
Soft-pack lithium batteries: Soft-pack lithium batteries are simply liquid lithium batteries encased in a thin polymer shell. Structurally, they use aluminum-plastic film packaging. In the event of a safety hazard, soft-pack batteries are most prone to bulging and cracking at the nozzle.
The structural characteristics of pouch lithium batteries: The key materials used in pouch lithium batteries—positive electrode materials, negative electrode materials, and separators—are not much different from those in traditional aluminum-cased lithium batteries. The biggest difference lies in the soft packaging material (aluminum-plastic composite film), which is the most critical and technologically advanced material in pouch lithium batteries.
Advantages of pouch lithium batteries:
It has a wide range of applications.
In terms of the shape of pouch polymer lithium batteries, pouches can be made into any shape. For motor vehicles, assembling pouch batteries can increase the space in the vehicle. On the other hand, the assembly position of pouch batteries is not affected by the structural type of the motor vehicle.
Extremely thin and space-saving, pouch batteries allow for even thinner designs. They offer greater overall operational flexibility and compatibility, making them highly attractive to automakers in terms of design concepts.
With high safety performance, the soft-pack battery structure uses aluminum-plastic film encapsulation. The biggest competitive advantage of aluminum film encapsulation is its flexibility. When the battery has a safety problem, the soft-pack battery will usually bulge and crack, and the liquid inside will leak out, but it will not cause the gas to be unable to escape, thus preventing an explosion or fire.
Small in size and light in weight, soft-pack polymer lithium batteries offer advantages such as light weight, large capacity, low internal resistance, and flexible design. These characteristics are gradually revealing their competitive advantages and highlighting their important position.
Low internal resistance. The internal resistance of pouch batteries is lower than that of lithium batteries. Currently, the internal resistance of domestically produced pouch battery cells can be as low as 35mΩ, which greatly reduces the self-discharge of lithium battery packs.
The flexible design of pouch lithium batteries allows for customization of the shape to meet customer market demands, enabling the development of cell models that expand the market.
Hard-pack lithium batteries: These are further divided into cylindrical and square shapes. The packaging structures differ. Each has its own advantages and disadvantages, primarily depending on the specific market demands. Ensuring consistency in hard-pack lithium batteries is relatively difficult, as the number of models increases and consistent processing techniques become harder to maintain. They are suitable for customized manufacturing but not for automated production of lithium battery packs.
What are the differences between pouch and hard pack lithium batteries?
The main difference between soft-pack and hard-pack lithium batteries lies in the material of the battery pack casing. If there is packaging, it is not so easy to tell the difference. Try to see the battery itself. Aluminum-cased batteries are heavier than batteries of the same volume. However, it is not so easy to distinguish between aluminum-cased and soft-pack batteries. Soft-pack batteries are softer than aluminum-cased batteries and are very easy to deform by bending them with your palm.
Are pouch cells or rigid lithium batteries better?
Lithium-ion batteries, both soft-pack and hard-pack, have their own differences, advantages, and disadvantages. Soft-pack batteries often use lithium polymer batteries, offering higher safety levels. Aluminum-cased models, such as the 18650, are the majority of lithium-ion batteries and have a long lifespan. Soft-pack batteries represent the most realistic scenario, and their venting is relatively better. Hard-pack batteries offer better heat dissipation and are generally safer. Ultimately, as long as lithium-ion battery packs are purchased from reputable brand-name products through official channels, which have undergone testing and certification by relevant companies, the product quality and safety are more assured.
