Battery pouches serve as the protective and flexible enclosures for the vital components within lithium-ion batteries, making them an integral part of the battery construction process. This article delves into the intricate construction of these multi-layered pouch films and explores how each layer contributes to their overall performance and characteristics.
The manufacturing process commences with the surface treatment of one side of the aluminium foil, which forms the core layer of the pouch. This aluminium foil is responsible for shaping the pouch and providing essential barrier properties to safeguard the battery’s contents. The surface treatment facilitates the adhesion of various polymers onto the foil, ensuring their secure attachment.
Polyamide and Polyester: The Dual-Purpose Outermost Layer
The outermost layer of the pouch consists primarily of polyamide (such as nylon) and polyester (such as PET). This layer serves a dual purpose: it provides external protection and reinforces the aluminium foil layer beneath. PET offers exceptional strength, while polyamide (PA) enhances flexibility and moldability. The choice between these materials or a combination thereof depends on the specific requirements of the application. The other side of the foil undergoes another treatment to enhance adhesion and protect against potential chemical attacks from the battery’s contents. The assembly process continues with the application of another layer of adhesive, distinct from the first, as it connects to different treatments and polymers. This layer binds the innermost heat-sealing layer to the aluminium core. The innermost heat-sealing layer, typically composed of polypropylene (PP), is chosen for its outstanding chemical resistance and lower melting point. This layer not only forms a secure bond with the PP film on the battery’s tabs but also plays a pivotal role in maintaining the pouch’s structural integrity.
Importantly, all the polymer layers in the pouch contribute to its barrier properties and overall ductility, ensuring that the battery remains protected and flexible. In the realm of lithium-ion batteries, the construction of pouch films is a meticulous process where each layer serves a specific purpose. The choice of materials and treatments at each stage influences the pouch’s performance, flexibility, and protective capabilities. The choice of appropriate thickness depends on the content of the pouch as thicker pouch supports higher formability.
Battery pouches are a critical component in the construction of lithium-ion batteries, serving as the flexible outer casing that houses the battery’s core components. These pouches play a pivotal role in ensuring the overall performance, safety, and form factor of the battery. In this article, we are looking at the construction of this multi-layer material and how individual layers influence the
Layer by Layer: Crafting the Protective Shell of Battery Pouch Films
The manufacturing begins with surface treatment on one side of the aluminium foil, which is core layer of the pouch will provide the shape and barrier properties of the composite, the treatment enables adhesion of other polymers onto the foil. An adhesive, a few microns thick, is used to join the outermost layer, where the main material is polyamide (such as nylon) and polyester (such as PET), this layer provides external protection and reinforcement for the aluminium foil layer. PET is stronger than PA but less mouldable, hence the use of one material or both depends on application. The foil is then treated on the other side for adhesion enhancement and corrosion resistance to protect against potential chemical attack from the contents. Another layer of adhesive is needed to bind the heat-sealing layer to the aluminium layer. This adhesive might be the different from the first as they are connecting to different treatment and polymer. The innermost heat-sealing is polypropylene, PP is adopted for its excellent chemical resistance and lower melting point. It also forms a strong bond with the PP film on the tabs as well. All polymer layers contribute to barrier properties in some extent and ductility of the composite.