Tabs are a type of raw material used in lithium-ion polymer batteries. For example, they are used in everyday products such as mobile phone batteries, Bluetooth batteries, and laptop batteries.
Batteries have positive and negative terminals. The tabs are the metal conductors that connect the positive and negative terminals from the battery cell. Simply put, the tabs on the positive and negative terminals are the contact points during charging and discharging. These contact points are not the copper plates on the outside of the battery, but rather an internal connection. Battery tabs are made of three materials: aluminum (Al) for the positive terminal, nickel (Ni) for the negative terminal, and sometimes copper-plated nickel (Ni-Cu) for the negative terminal. All of these are composed of a composite of a film and a metal strip.
The insulating film on the tab is used to prevent short circuits between the metal strip and the aluminum-plastic film during battery encapsulation. It also prevents leakage by heat-sealing the film together during encapsulation (around 140℃). Each tab consists of two films sandwiching the metal strip. There are three types of films used in the market: black film, white film, and single-layer film. Commonly used black film has a three-layer structure: black pigment (melting point 66℃), PE (melting point 105℃), and PP (melting point 137℃).
The finished packaging of the electrode is divided into tray type (the whole metal strip is wound into a tray after the film is added by the equipment) and plate type (the metal strip is cut into individual pieces after the film is added, and then arranged in rows with two thin transparent plastic sheets sandwiched in the middle).
However, Tesla's 46800 battery is a tabless battery, reportedly a revolutionary invention that increases driving range by 54% and reduces costs by 56%. So, what is a tabless battery?
A tabless battery is essentially a battery without a motor interface or tabs; it is still a lithium-ion battery at its core. Therefore, it is not a new type of battery; its innovation lies mainly in the arrangement of the lithium-ion cells and the method of power extraction.
Although tabless batteries look similar to ordinary batteries, being cylindrical in shape, their internal structure is completely different. They consist of thin films made from the positive and negative electrodes and the battery chemicals in between, stacked together, and then rolled up.
Tabletop batteries have four advantages:
1. Charged particles no longer need to penetrate very thick batteries; they only need to penetrate a thin film, so their losses will definitely be less.
2. The electrodes at both ends were removed directly, eliminating the need to make two separate electrodes for current conduction. Instead, the two ends of the thin film have a long section that can be used for current conduction, thus eliminating the extra losses caused by the original two electrodes.
3. Electric vehicles require large battery packs, which leads to battery heat generation. Traditional batteries with tabs have relatively small contact points, causing current congestion and uneven heating. Tabletop batteries, on the other hand, distribute current more evenly, resulting in more uniform heat generation and making overall heat dissipation easier.
4. Because there are no battery tabs, eliminating the need for additional components, it saves even more money!
