Storage #
Battery cells suffer from stress when exposed to heat or high charge voltage. Storage conditions above 35°C are considered elevated temperature and accelerate aging. State of Charge (SOC) above 95% is considered to be high SOC. Exposing the battery to elevated temperature and storing at high SOC for an extended time can be more stressful than cycling. The table below demonstrates capacity loss as a function of temperature and SOC.
| Temperature | 40% Charge | 100% Charge |
|---|---|---|
| 0°C | 98% (after 1 year) | 94% (after 1 year) |
| 25°C | 96% (after 1 year) | 80% (after 1 year) |
| 40°C | 85% (after 1 year) | 65% (after 1 year) |
| 60°C | 75% (after 1 year) | 60% (after 3 months) |
It is important to not allow the battery to self-discharge below the operating voltage limit set out in the datasheet, as it will cause irrevocable damage to the battery. A battery in undervoltage condition will not power up and is unsafe to operate.
When storing the battery at elevated temperature, frequent supervision is necessary, and re-charging might be required if SOC falls below 20%.
Storing and operating the battery at an elevated temperature increases the calendar aging rate. Every 10°C above 30°C doubles the calendar and cycling aging rate.
Operating Conditions #
The battery management system (BMS) continuously broadcasts available power that is dynamically calculated via a complex algorithm, taking into account temperature readings from temperature sensors distributed across each module. The algorithm applies a de-rating factor if the internal temperature (not environment) is outside of the specified window.
The available power and usable energy capacity depends on the temperature. Charging and discharging efficiency is decreased when the battery cell temperature is below 20°C. Usable capacity and power return to nominal values when the temperature increases.
Charge #
Charging is not permitted when the battery cell temperature is below 0°C.
Discharge #
The usable energy capacity of the battery system depends on the operating temperature. Discharging under low temperature (<20°C) will result in decreased energy throughput during the discharging cycle. Usable capacity returns to the specification value when the temperature increases.
Vibration #
Xerotech recommends frequency isolation within the following ranges:
- X and Y: 10 – 80 Hz
- Z: 60 – 180 Hz
This data is to support the integration partners only and does not constitute any formal sign off of the installation. It also assumes a horizontal installation.
