How Are LiPo Batteries Made?

In an age of cell-phones, MP3 players and digital cameras, batteries have become ubiquitous. Checking your personal device, you will probably find a nickel-cadmium battery, but it could be a lithium-ion. A relative of the lithium-ion is the lithium-ion polymer battery, which marks a progression from the standard lithium type and the lithium-ion. As the lithium-ion battery is slowly supplanting the nickel-cadmium type, the lithium-ion polymer stands as the next progression.?

History
Work on the lithium battery began in 1912, but it was not completed until the 1970s, according to Battery University. The 1912 version of the lithium battery was lightweight, nearly half the density of the nickel-cadmium. But the original lithium batteries were non-rechargeable, as were later models, because of lithium's instability.

Sony manufactured the lithium-ion battery in 1991, and the lithium-ion polymer battery followed five years later. In 2003, Kwon-sun Roh, Jae-myoung Lee and Jon-ha Lee invented a gel-infused lithium-ion polymer, the most recent progression.

Features
A lithium battery contains a carbon anode and a lithium cathode. An electrolyte allows ions to pass between the two materials, producing a voltage. A lithium-ion battery has a fluid electrolyte, while a lithium-ion polymer battery has a solid electrolyte. This solid electrolyte has the shape and consistency of transparent film. Because of the solid electrolyte, the lithium-ion polymer can be constructed in circular, wound, or flat, stacked, designs.

Process
The manufacturing environment of a lithium-ion polymer battery is similar to that of a nickel-cadmium. Mass assembly of batteries is carried out on automated factory equipment, which can reduce damage to the battery components, according to MPowerUK.

The first step in the lithium-ion polymer construction is mixing binding agents with the carbon and lithium (for the anode and cathodes), which are then applied to sheets of copper (anode) and aluminum (cathode). After drying, the coated sheets are wound together around the polymer electrolyte. Then the connections and terminals are welded onto the wound sheets or flat stacks, completing the battery.

Significance
The first lithium battery was unstable and could not be properly recharged. The lithium-ion battery was created to solve that problem. But the lithium-ion, because it contained a fluid electrolyte, required a solid encasing, meaning more material. Additionally, the lithium-ion was unstable when overcharged, and it often leaked its fluid electrolyte core.

The lithium-ion polymer needs neither a solid case nor a liquid reservoir, and it's smaller than the lithium-ion. Relative to the lithium-ion, the polymer type is stable, it resists overcharging, and it does not leak.

Potential
The solid electrolyte of the lithium-ion polymer battery can be manufactured to paper-size widths. A polymer battery could potentially be the size of a credit card. Areas without electricity could benefit from the lower shipping weight and size of this type of battery.

Considerations
For the lithium-ion polymer, Battery University lists a high cost-to-energy ratio in relation to the lithium-ion, and a higher manufacture expense, as limitations. The 2003 gel-infused polymer battery from Roh, Lee and Lee is designed to increase the cycling capacity, thereby reducing the cost-to-energy ratio, but it has yet to be mass manufactured.