A detailed guide on Li-ion pouch cells: What are they and their benefits?

When shell battery explosions were troubling people, scientists had to think of something better. How about a soft-pack battery that would generally bulge and not explode if a malfunction occurs? Sounds better, doesn’t it? 

In the 1990s, the fresh design of the pouch cells surprised the battery gurus. Unlike other batteries that come with a metallic cylinder, pouch cells have a polymer exterior that gives them superior flexibility. 

With outstanding performance, durability, longer life, and high compatibility, these pouch-cell batteries are suitable for a wide range of applications. 

You will find them in portable consumer electronic devices such as GPS, DVDs, iPods, tablets, PCs, MP4 players, power banks, IoT, medical equipment, and electric vehicles. 

Interesting, aren’t they? Let’s explore the details about li-ion pouch cells, their working, pros, cons, and more. 

What are Li-ion pouch cells? 

As the name suggests, li-ion pouch cells are battery cells assembled in pouches. The pouch is made up of a layer of aluminum-coated plastic film. 

You will not find any hard metal cases. Eliminating the metal enclosure reduces the weight of these cells. They are also called Lipo (Lithium Polymer) cells or soft packs. 

A pouch cell has the following elements:

• Current collectors: The conductive materials (copper and aluminum) carry electrical current 
• Active material: It is the electrode
• Anode: The negative current collector and the active material
• Cathode: The positive current collector and the active material
• Separator: A separation that prevents electrical contact between the anode and the cathode.  

In recent times, pouch cells have become the first choice for many manufacturers because they offer a high energy density and great power performance in addition to design advantages. 

How are Li-ion pouch cells made? 

Wondering how these flexible pouch cells are made? The following steps will give you a complete understanding of the process:  

• Electrode Slurry: A slurry is created by mixing electrode powders and active materials like lithium with binding materials.
• Electrode Coating: This slurry is spread onto long foil pieces. It is baked at a very high temperature, up to 300 degrees Fahrenheit. 
• Electrode Stamping: After baking, individual electrode battery pieces are cut.
• Electrode Stacking: A suction machine picks up the cut-out electrodes and wraps a separator layer between them to create an electrode stack. 
• Pouch Making: Each electrode stack is kept in a moisture-resistant material to create a pouch cell.
• Electrolyte Injection: A machine injects liquid electrolyte into every open pouch.
• Sealing: The pouch cell is then heat-sealed. It is kept in a vacuum chamber to eliminate excess air from the pouch.

Working of Li-Ion Pouch Cells

Lithium-ion pouch cell manufacturers are constantly hunting for ways to enhance the efficiency and reliability of their products while minimising manufacturing costs. 

You must know that the service life and the performance of pouch cells largely depend on the processing technique.

Let’s understand the working of the pouch cells, which is easy to grasp! 

The working of li-ion pouch cells is similar to that of any other cell. It has electrodes that conduct electrical current. 

You will find two tabs sticking out of the pouch— the positive and negative connector tabs that help conduct electric energy in and out of the pouch cell when connected to the required sources. 

Power Generation from Li-Ion Pouch Cells 

From laptops to cell phones, lithium-ion pouch cell batteries power the lives of millions of people each day. 

So, how does it work?

Like any other cell, a chemical reaction occurs inside a pouch cell whenever an electric current is passed through it. 

Lithium-ion movement creates free electrons at one of its electrodes (anode). The electrical current flows from the anode through a powered device to the negative current collector. 

When discharging to provide an electric current, electrons flow from the anode to the cathode. 

And what would happen when it charges a device? The contrast. When you plug in the device, the ions are released from the cathode and received by the anode.

The li-ion pouch cell batteries favours intermittent charging. Therefore, you need not charge these to saturation. 

Pricing of Li-Ion Pouch Cells 

Planning to purchase lithium-ion pouch cells/batteries? You must know that the price is largely influenced by the manufacturing company, the voltage, and the capacity. 

A li-ion pouch cell battery with:

• 3.7V and 10,000 mAH costs approximately ₹500 
• 3.7V and 4000 mAH costs between ₹275 to ₹300 
• 3.7V and 600 mAH costs between ₹100 to ₹170 
• 3.7V and 300 mAH costs between ₹90 to ₹120

Pros and Cons of Li-Ion Pouch Cells 

Let us discover both sides of a pouch cell– its merits and limitations before adopting it. 

Pros

The reasons that have made pouch cells highly popular are as follows:

• High production speed
• Easy maintenance
• Better recycling capabilities
• Greater flexibility 
• Longer cycle life with only about a 10% decline over ten years
• Improved energy storage in comparison to cylindrical cells
• Greater safety as they do not explode
• Very lightweight– 40% lighter than an equivalent capacity shelled lithium battery
• A small size that greatly reduces the self-consumption of the cell/battery

Cons

We know you are eager to discover if these pouch cells have any disadvantages. So, here are some limitations.

• Due to swelling, pouch cells can gain 10% volume after 500 charge cycles.
• They are higher in price than other alternatives, such as cadmium cells. 
• They are easy to damage and prone to leakage if not manufactured up to the mark. 
• Very high temperatures can reduce their longevity.   

Why isn’t solar energy more popular? 

Installing a solar system demands a bone-breaking investment – this is a myth! And this myth has caused a majority of people to back out from installing a solar energy system. 

Although we agree that the cost is marginally higher, the long-term monetary benefits of opting for a solar system cannot be overlooked. 

If there’s more awareness and people get to understand that switching to solar will benefit the planet too, solar energy will be easily adopted on a larger scale.

Conclusion 

Pouch cells are light and cost-effective. However, exposure to humidity and high temperature can shorten their life. 

These cells work best with light loading and moderate charge times. As they can serve various industries, they have gained strong customer loyalty over the years. 

FAQs

Q1. Are pouch cells safe?

Li-ion pouch cells are safe and have a low-risk fraction. They are known to swell due to manufacturing defects or overuse, but they do not explode like other cell types.

Q2. Are pouch cell batteries good?

Pouch cells have up to 90% to 95% packaging efficiency— the highest among battery packs. They are lightweight and have a longer life; hence, they’re absolutely worth it.