UL 1642

Electrical Tests

• Short-Circuit Test:
  • Parameters: Each fully charged sample is externally short-circuited using a copper wire or total loop resistance of 80±20mΩ.
  • Conditioning: Conducted at two ambient temperatures: room temperature (20±5°C) and elevated temperature (55±5°C). The test runs until the sample returns to ambient temperature or for a minimum of 24 hours.
  • Criteria: No fire and no explosion. External case temperatures typically must not exceed 150°C.
• Abnormal Charging Test:
  • Parameters: Fully discharged cells are subjected to a continuous reverse or high charge current equal to three times (3x) the manufacturer-specified maximum charging current (I_chg).
  • Duration: The test continues for a minimum of 7 hours, or until the sample blows an internal protective mechanism or reaches steady state.
  • Criteria: No fire and no explosion.
• Forced-Discharge Test:
  • Parameters: Evaluates cells connected in multi-cell series arrangements where one discharged cell can be reverse-driven by the remaining charged cells.
  • Conditioning: A fully discharged cell is connected in series with a DC power supply or fully charged cells and forced into over-discharge at a specified test current for a set duration.
  • Criteria: No fire and no explosion.

Mechanical Tests

• Crush Test:
  • Parameters: The cell is crushed between two flat parallel surfaces (often using a hydraulic piston) with an applied force of 13±1kN.
  • Application: Applied perpendicular to the longitudinal axis (or along the broad and narrow faces for prismatic/pouch cells). Once the peak force is achieved, it is released.
  • Criteria: No fire and no explosion.
• Impact Test:
  • Parameters: A 15.8mm (5/8-inch) diameter steel rod or round bar is positioned across the centre of the cell. A 9.1±0.46kg weight is dropped from a height of 610±25mm onto the bar.
  • Orientation: Performed on the cell’s long axis (or perpendicular to the wide face for flat cells).
  • Criteria: No fire and no explosion.
• Round Bar Crush Test:
  • Parameters: An alternative or specialized deformation method (frequently utilized for larger formats/prismatic cells) where crushing force is directed through a rounded steel bar across the face rather than flat plates to test local structural puncture resistance.
  • Criteria: No fire and no explosion.
• Shock Test:
  • Parameters: Cells are secured to a shock-testing rig and subjected to half-sine shock pulses with an acceleration peak of 150 g and a nominal duration of 3 ms.
  • Repetitions: 3 pulses applied in each direction along 3 mutually perpendicular axes (18 shocks total).
  • Criteria: No fire, no explosion, no leakage, and no venting.
• Vibration Test:
  • Parameters: Simple harmonic motion with an amplitude of 0.8mm (1.6mm total excursion).
  • Frequency Range: Swept between 10Hz and 55Hz at a rate of 1Hz/min.
  • Duration: Swept traversed along each of the three perpendicular axes for 90 to 100 minutes per axis.
  • Criteria: No fire, no explosion, no venting, and no leakage.

Environmental Tests

• Heating Test (Thermal Abuse):
  • Parameters: Samples are placed in a gravity or circulating-air oven starting at room temperature and heated at a rate of 5±2°C/min up to 130±2°C.
  • Hold Time: Maintained at 130°C for 10 minutes (or up to 150°C depending on the cell chemistry/revision specifications).
  • Criteria: No fire and no explosion.
• Temperature Cycling Test:
  • Profile:
    1. Raise from 20°C to 70±3°C in 30 minutes; hold for 4 hours.
    2. Lower to 20±3°C in 30 minutes; hold for 2 hours.
    3. Lower to -40±3°C in 30 minutes; hold for 4 hours.
    4. Return to 20±3°C in 30 minutes.
  • Cycles: Repeated for 10 complete cycles, followed by a minimum 24-hour rest at room temperature.
  • Criteria: No fire, no explosion, and no leakage/venting.
• Low Pressure (Altitude Simulation) Test:
  • Parameters: Cells stored for 6 hours at an absolute chamber pressure of 11.6kPa (1.68psi) and an ambient temperature of 20±3°C.
  • Equivalent Simulation: Simulates an unpressurized aircraft cargo bay at an altitude of approximately 15,000m (50,000ft).
  • Criteria: No fire, no explosion, no rupture, and no leakage.

Fire Exposure

• Projectile Test:
  • Apparatus: The test sample is placed over a 102 mm (4-inch) central hole on a horizontal metal rack covered with an open mesh wire screen. An octagonal cage of wire mesh (8 panels, 610mm wide x 305mm high, 16–18 wires per inch) encloses the test area.
  • Procedure: A gas burner heats the cell directly until thermal runaway, combustion, or full destruction occurs.
  • Criteria: The cell or any ejected fragment must not penetrate the surrounding octagonal wire mesh screen. Any flame, sparks, or molten debris must remain contained within the screen envelope.