Vacuum drying

Example

Use in Lemonergy

Place operations and quality checks in process order.

This is a reference concept. No executable Lemonergy block has been verified for this term.

Learn it in Lesson 3 · Cell production →

Connected concepts

Related concepts from the knowledge graph. Connections show context, not cause and effect. Hover or focus a linked term for its definition.

Dry room

A production room whose air is kept extremely dry — dew points around −30 °C to −60 °C — so that no moisture reaches the cell while the electrolyte goes in. Water would react with the salt LiPF₆ to form hydrofluoric acid.

Hydrofluoric acid

Formed when LiPF₆ electrolyte meets water, or when a fluorinated cell burns. Inside a cell traces of it attack the positive electrode and SEI; in a fire it is the most dangerous component of the vented gas.

Lithium salt

The dissolved salt that supplies the mobile lithium ions in a liquid electrolyte, almost always lithium hexafluorophosphate, LiPF₆, at about one mole per litre. It reacts with traces of water to form hydrofluoric acid, which is why cells are filled in a dry room.

Moisture content

The water left in electrodes, separator and electrolyte, measured by Karl Fischer titration and specified in the low hundreds of parts per million or below. Water forms HF with the salt, which attacks the positive electrode and the SEI.

References & further reading

Technical references

1. Current and future lithium-ion battery manufacturing

   Yangtao Liu, Ruihan Zhang, Jun Wang, Yan Wang · iScience · 2021

   Technical reference · Electrode preparation, cell assembly, formation and manufacturing trade-offs.