Gas generation

Example

Use in Lemonergy

Separate mechanisms, observations and fitted models.

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

Learn it in Lesson 4 · Battery aging →

Connected concepts

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

Degassing

Removing the gas a cell releases during formation. A pouch cell’s extra gas pocket is opened in a dry atmosphere, emptied and sealed off; large prismatic cells often vent through their fill opening before final sealing.

Electrolyte decomposition

Reduction of the electrolyte at the negative electrode and oxidation at the positive, outside its stability window. A little is useful — it builds the SEI — but continued decomposition consumes lithium, dries the cell and makes gas.

Formation

The first controlled charge and discharge cycles of a newly assembled cell, during which the SEI forms. It is part of cell production, before aging and grading.

Swelling

Growth in a cell’s thickness, reversibly as the electrodes expand on charge and irreversibly as gas and SEI accumulate. Packs allow for it with compression pads, and a sudden swell in service is a warning sign.

Vent

A scored area or a membrane in the cell can that opens at a set pressure, around ten to thirty bar for a cylindrical cell, so that gas escapes in a chosen direction instead of the case splitting at random.

References & further reading

Technical references

1. Lithium ion battery degradation: what you need to know

   Physical Chemistry Chemical Physics · 2021

   Technical reference · Degradation mechanisms, modes, operational effects and their interactions.