Coefficient of thermal expansion

Example

Use in Lemonergy

Select spatial detail for the question.

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

Connected concepts

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

Busbar

A rigid copper or aluminium conductor that joins cell terminals into series and parallel groups, and modules into the pack. Its cross-section is sized for current and heating, and its joints — welded or bolted — are a classic source of resistance and failure.

Glass transition temperature

The temperature at which an amorphous polymer turns from hard and glassy to soft and rubbery, with a sharp fall in stiffness and rise in expansion. Adhesives, potting compounds and circuit boards are chosen with Tg clear of the operating range — standard FR-4 board is about 130–140 °C — so their joints are not loaded differently in service.

Structural adhesive

A load-bearing adhesive, usually epoxy, polyurethane or acrylic, that bonds cells to each other, to the tray or to the lid so the cell block becomes part of the structure. Cell-to-pack and cell-to-chassis designs rely on it, at the price of cells that are hard to replace or to separate for recycling.

Thermal shock and cycling test

Moving a cell or pack rapidly between temperature extremes, typically −40 °C and +60 to +85 °C, for many cycles, to find seals, welds and housings that fail by differential expansion. It is in UN 38.3, R100 and most pack specifications.

Thermal stress

Mechanical stress caused by a temperature change when a part cannot expand freely or is joined to a material that expands differently. A fully restrained aluminium bar warmed by 50 K would carry about 80 MPa. Repeated cycles fatigue welds, solder joints and adhesive bonds, which is what thermal shock testing sets out to provoke.

References & further reading

Further reading on this topic

These sources provide broader context; they are not presented as citations for every statement in this entry.

1. A General Energy Balance for Battery Systems

   Dawn Bernardi, Ellen Pawlikowski, John Newman · Journal of The Electrochemical Society · 1985

   Topic background · Battery energy balance and irreversible and reversible heat contributions. Reduced thermal models require explicit assumptions and current-sign conventions.

2. University Physics Volume 2, §1.6: Mechanisms of Heat Transfer

   OpenStax, Rice University

   Topic background · Conduction, convection, radiation and thermal resistance.