UN 38.3: Ensuring Safe Transportation of Lithium Batteries

T.1 — Altitude Simulation

Purpose: Simulates low-pressure conditions experienced in high-altitude air transport, such as unpressurized cargo holds.

Procedure:
Batteries are stored at a pressure of ≤ 11.6 kPa (approximately the pressure at ~15,000 m) at around 20 ± 5 °C for at least 6 hours.

What It Checks:

• Sealing integrity
• No leakage, venting, rupture, or fire
• Voltage retention (generally ≥ 90% for many batteries)

T.2 — Thermal Test (Temperature Cycling)

Purpose: Assesses resistance to thermal extremes and rapid temperature swings during transport.

Procedure:
Repeated cycles between high (≈ 72–75 °C) and low (≈ −40 °C) temperature environments — typically 6 hours at each extreme, with a quick transition between them. The cycle repeats 10 times, followed by a 24 hour room-temperature rest.

What It Checks:

• Structural stability under temperature shock
• Electrolyte and seal durability
• No leakage, venting, or rupture

T.3 — Vibration

Purpose: Simulates mechanical vibration experienced during transport by road, rail, and air.

Procedure:
A sinusoidal vibration sweep (7 → 200 → 7 Hz) is applied over about 15 minutes, repeated 12 times along each of three perpendicular axes (for a total of 3 hours).

What It Checks:

• Mechanical and structural durability
• Connector and internal component stability
• No loosening that could lead to short circuits

T.4 — Shock

Purpose: Tests the battery’s ability to withstand sudden mechanical impacts like drops or handling jolts.

Procedure:
Half-sine shock pulses (e.g., 150 g for small batteries, 50 g for large ones) with defined pulse durations are applied across six directions (±X, ±Y, ±Z), typically three pulses per direction.

What It Checks:

• Internal structural integrity
• Resistance to impact-induced faults

T.5 — External Short Circuit Test

Purpose: Simulates a direct short between battery terminals under controlled thermal conditions to assess safety.

Procedure:
Batteries are heated to around 55 ± 2 °C, then subjected to an external short circuit with resistance < 0.1 Ω. Temperatures are monitored, typically for the duration needed for the battery surface to return to the initial temperature, with observation extending 6 hours after.

What It Checks:

• Whether the battery remains safe without fire, explosion, rupture, or unsafe temperatures (commonly < 170 °C)

T.6 — Impact / Crush Test

Purpose: Evaluates how cells withstand severe mechanical abuse that could cause internal short circuits.

Procedure (Cell Type Dependent):

• Impact: For large cylindrical cells (≥ 18 mm diameter), a mass is dropped onto the cell with a cylindrical impactor.
• Crush: For prismatic, pouch, small cylindrical, or coin cells, a compressive load is applied until a force threshold or deformation.

What It Checks:

• Resistance to deformation
• No fire, rupture, or hazardous temperature rise after impact or crushing

T.7 — Overcharge Test

Purpose: Assesses safety when a rechargeable battery is charged beyond its normal limits (e.g., protection circuit failure).

Procedure:
Rechargeable units are charged at twice the maximum recommended current and a defined voltage threshold over a set period (e.g., 24 h).

What It Checks:

• Whether internal protection, venting, or safety mechanisms prevent fire, explosion, or rupture, often observed up to 7 days after the test.

T.8 — Forced Discharge Test

Purpose: Evaluates safety when a battery is forced to discharge rapidly, such as through external loads or cascade failures.

Procedure:
A maximum specified discharge current is applied until the battery is fully discharged under controlled conditions.

What It Checks:

• No fire, explosion, or rupture
• Safe behavior even under aggressive discharge conditions