HOT. Hottest point reaches 74.5 C (limit 60 C) at (18.5, 18.5, 31.8) mm after 60 min. It passes 60 C after about 21.1 min.

Confidence: high. passed mesh convergence, energy balance, hand calculation, units and sanity
max temperature: 74.5 C
limit: 60 C
power: 6 W
mesh nodes: 9,610

Checks:
  [pass] mesh convergence: temperature rise at the hottest point settled: 39.5 -> 39.5 C over 2 meshes, last change 0.0%
  [pass] energy balance: over 60 min, heat in 21.6 kJ, stored 7.98 kJ, out through the surfaces 13.4 kJ (1% apart)
  [pass] hand calculation: lumped model with convection and radiation (Biot 0.012) gives a mean of 72.2 C at the end; FEA mean is 72.8 C (1.6% of the rise)
  [pass] units and sanity: temperatures between 69.5 and 74.5 C

Assumptions:
  - Li-ion cell (lumped, effective): conductivity 3 W/(m K), specific heat 950 J/(kg K), density 2500 kg/m3.
  - Heat is generated evenly through the part.
  - Convection uses a fixed film coefficient; real coefficients vary with temperature and airflow.
  - Surrounding air or coolant at 35 C does not heat up.
  - Radiation with emissivity 0.9.
  - Contact resistance between parts and internal airflow are not modeled.

Suggested fixes:
  - Raise heat transfer about 2x: The temperature rise scales with 1/(h A). A small fan takes h from about 5 to 25 W/(m2 K); fins or a larger case add area. Either way you need about 2x the current 5 W/(m2 K) times area.
  - Cut the power to 3.04 W: Lower current or duty cycle; the rise is proportional to the heat made.

Images: temperature: images/temperature.png, history: images/history.png
Report: report.html
