Pouch cells are a popular type of lithium-ion battery that are widely used in various applications, such as electric vehicles, portable electronics, and grid storage systems. They consist of a flexible pouch or bag that contains the active electrode materials, electrolyte, and separator, and are sealed with a lead tab that provides the electrical connection to the outside world.

However, lead tabs in pouch cells can experience various failure modes that can reduce the performance, safety, and reliability of the cell. Some of the common failure modes of lead tabs include detachment, fracture, corrosion, oxidation, short circuit, and thermal runaway. These failure modes can be caused by various factors, such as mechanical stress, chemical reactions, and electrical
abuse.

The failure modes of lead tabs in pouch cells can include:

  • Tab detachment: The lead tab can detach from the electrode, causing a loss of electrical connection and reducing the cell’s performance.
  • Tab fracture: The lead tab can fracture due to excessive mechanical stress or fatigue, leading to a loss of electrical connection and reduced performance.
  • Tab corrosion: The lead tab can corrode due to exposure to moisture or other corrosive substances, leading to a loss of electrical connection and reduced performance.
  • Tab oxidation: The lead tab can oxidize due to exposure to air or other oxidizing substances, leading to a loss of electrical connection and reduced performance.
  • Tab short circuit: The lead tab can come into contact with another part of the cell, causing a short circuit and potentially damaging the cell.
  • Tab thermal runaway: The lead tab can heat up due to high current or other factors, leading to thermal runaway and potentially causing the cell to catch fire or explode.

To prevent these failure modes and ensure the long-term performance and safety of pouch cells, manufacturers need to carefully select the materials and specifications of the lead tabs. The lead tabs should be made of high-quality materials that can withstand the demands of the battery application and the corrosive and oxidative environments inside the cell.

Here are some of the key material specifications that can help prevent failure modes of lead tabs in pouch cells:

  • Purity: The lead used for the tabs should have a high degree of purity to minimize impurities that can cause corrosion or other chemical reactions inside the cell.
  • Conductivity: The lead tabs should have high electrical conductivity to minimize resistance and improve performance. Other conductive coatings or additives, such as silver or copper, can also be used to improve conductivity.
  • Thickness: The thickness of the lead tabs can affect their mechanical properties, such as stiffness and flexibility, and their resistance to fatigue and stress. The thickness should be optimized for the specific cell design and application.
  • Coating: The lead tabs can be coated with various materials, such as nickel or tin, to improve their resistance to corrosion or oxidation. The coating should be selected based on the specific requirements of the cell chemistry and environment.
  • Adhesion: The lead tabs should be able to bond strongly to the electrode material to prevent detachment or fracture during cycling. Various adhesion methods, such as ultrasonic welding or conductive adhesives, can be used to improve bonding.

By using high-quality materials and optimizing the specifications of the lead tabs, manufacturers can prevent failure modes and improve the performance, safety, and reliability of pouch cells. Avocet Battery is a leading provider of high-quality pouch cells and related products for various applications, and is committed to using the best materials and practices to ensure customer satisfaction and success.

In conclusion, lead tabs in pouch cells can experience various failure modes that can reduce their performance and safety, but these failure modes can be prevented by using high-quality materials and optimizing the specifications of the lead tabs. By doing so, manufacturers can improve the long-term performance and reliability of pouch cells, and provide better solutions for their customers.

Visit www.avocetbattery.com to learn more about our products and services, and how we can help you succeed in your battery applications.