UN 38.3 Transportation Test

For battery products to be exported or sold, obtaining un 38.3 certification is essential.

UN 38.3 refers to Section 38.3 of the "Manual of Tests and Criteria" compiled by the United Nations Committee of Experts on the Transport of Dangerous Goods. It outlines safety performance testing for lithium batteries. This certification involves comprehensive safety performance tests based on various domestic and international standards, ensuring product quality and safety for battery manufacturers and enhancing export capabilities.

Test T.1: Altitude Simulation

1. Purpose

This test simulates air transport under low-pressure conditions, evaluating the stability and reliability of batteries in high-altitude environments such as airplanes and mountains.

2. Test Procedure

Test cells and batteries shall be stored at a pressure equal to or less than 11.6 kPa and at an ambient temperature of 20 ± 5°C for at least 6 hours.

3. Requirements

The test is considered passed if there is no leakage, no venting, no disassembly, no rupture, and no fire. Additionally, the open-circuit voltage of each test cell or battery after the test must be at least 90% of its voltage before the test. Voltage requirements do not apply to fully discharged test cells or batteries.

Test T.2: Thermal Test

1. Purpose

This test evaluates the integrity of the battery and internal electrical connections under rapid and extreme temperature changes.

2. Test Procedure

Test cells and batteries are stored at 72 ± 2°C for at least 6 hours, then at -40 ± 2°C for at least 6 hours. The maximum time interval between temperature extremes is 30 minutes. This cycle is repeated 10 times, followed by storage at 20 ± 5°C for 24 hours. For large batteries, exposure to extreme temperatures should be at least 12 hours.

3. Requirements

The test is passed if there is no leakage, no venting, no disassembly, no rupture, and no fire. The open-circuit voltage after the test must be at least 90% of the pre-test voltage. Voltage requirements do not apply to fully discharged test cells or batteries.

Test T.3: Vibration Test

1. Purpose

This test simulates vibrations during transportation to assess the battery's resistance to vibration.

2. Test Procedure

Cells and batteries are firmly secured to the vibration table without distorting them. A sinusoidal waveform vibration with a logarithmic frequency sweep from 7 Hz to 200 Hz and back to 7 Hz over 15 minutes is applied. This cycle is repeated 12 times for each of three mutually perpendicular mounting positions, totaling 3 hours.

- For cells and small battery packs (<12 kg):

- Maintain 1 gn acceleration up to 18 Hz.

- Then, maintain 0.8 mm amplitude (1.6 mm total displacement) and increase frequency until 8 gn acceleration is reached (approximately 50 Hz).

- Maintain 8 gn acceleration up to 200 Hz.

- For large battery packs (≥12 kg):

- Same as above, but maximum acceleration is 2 gn (approximately 25 Hz).

3. Requirements

The test is passed if there is no leakage, no venting, no disassembly, no rupture, and no fire. The open-circuit voltage after the third perpendicular vibration must be at least 90% of the pre-test voltage. Voltage requirements do not apply to fully discharged test cells or batteries.

Test T.4: Shock Test

1. Purpose

This test assesses the battery's ability to withstand cumulative shock effects.

2. Test Procedure

Cells and batteries are secured to the test machine using a rigid mount that supports all mounting surfaces.

- For small batteries:

- Subject to half-sine shock with a peak acceleration of 150 gn and pulse duration of 6 ms.

- For large batteries:

- Subject to half-sine shock with a peak acceleration of 50 gn and pulse duration of 11 ms.

Each cell or battery undergoes three shocks in each direction of three mutually perpendicular mounting positions, totaling 18 shocks.

3. Requirements

The test is passed if there is no leakage, no venting, no disassembly, no rupture, and no fire. The open-circuit voltage after the test must be at least 90% of the pre-test voltage. Voltage requirements do not apply to fully discharged test cells or batteries.

Test T.5: External Short Circuit

1. Purpose

This test simulates an external short circuit.

2. Test Procedure

Cells and batteries are stabilized at 57 ± 4°C. Then, they are subjected to a short circuit condition with a total external resistance of less than 0.1 ohm. The short circuit is maintained for at least 1 hour after the cell or battery case temperature returns to 57 ± 4°C.

3. Requirements

The test is passed if the case temperature does not exceed 170°C and there is no disassembly, rupture, or fire within 6 hours of the test.

Test T.6: Impact/Crush

1. Purpose

This test simulates mechanical abuse from an impact or crush that may result in an internal short circuit.

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2. Test Procedure – Impact (for cylindrical cells ≥18.0 mm in diameter)

The test sample cell or battery is placed on a flat, smooth surface. A 316 stainless steel rod with a diameter of 15.8 mm ± 0.1 mm and a length of at least 6 cm (or the longest dimension of the battery, whichever is longer) is placed across the center of the sample.

A 9.1 kg ± 0.1 kg weight is dropped from a height of 61 ± 2.5 cm onto the intersection of the rod and the sample. The weight is guided through a nearly frictionless vertical track, minimizing resistance. The test sample should be aligned such that its longitudinal axis is parallel to the flat surface, and the rod is placed at a right angle to the longitudinal axis. Each sample is only subjected to one impact.

2. Test Procedure – Crush (for prismatic, pouch, coin/button cells, and cylindrical cells ≥18.0 mm in diameter)

The battery or cell is placed between two flat plates and gradually subjected to crushing force. The speed of compression is approximately 1.5 cm/s. The test continues until one of the following conditions is met:

(a) The force reaches 13 kN ± 0.78 kN, for example, using a hydraulic press with a piston diameter of 32 mm until the pressure reaches 17 MPa.

(b) The battery voltage drops by at least 100 mV.

(c) The battery's thickness decreases by 50% or more.

Once any of the above conditions are met, the pressure is released.

Prismatic or pouch cells should be crushed from the widest side. Coin/button cells should be crushed from their flat surface. Cylindrical cells should be crushed perpendicular to their longitudinal axis. Each sample is subjected to only one crushing test. After the test, the sample should be observed for 6 hours. The test should use batteries or cells that have not been tested previously.

3. Requirements

The test is passed if the case temperature does not exceed 170°C and there is no disassembly, rupture, or fire during the test or within 6 hours after the test.

Test T.7: Overcharging

1. Purpose

This test evaluates the ability of a rechargeable battery pack or single rechargeable cell to withstand an overcharging situation.

2. Test Procedure

The charging current must be twice the maximum recommended continuous charging current provided by the manufacturer. The minimum test voltage is as follows:

(a) If the manufacturer's recommended charging voltage is ≤18 V, the minimum test voltage should be twice the maximum charging voltage or 22 V, whichever is smaller.

(b) If the manufacturer's recommended charging voltage is >18 V, the minimum test voltage should be 1.2 times the maximum charging voltage.

The test is conducted at ambient temperature for 24 hours.

3. Requirements

The test is passed if the rechargeable battery pack or single cell shows no disassembly or fire during the test and within 7 days after the test.

Test T.8: Forced Discharge

1. Purpose

This test evaluates the ability of a primary or rechargeable battery to withstand forced discharge conditions.

2. Test Procedure

Each battery is connected in series with a 12 V DC power supply, and the initial discharge current is set equal to the maximum discharge current specified by the manufacturer. The appropriate resistor and rated value are used to achieve the desired discharge current. The battery is subjected to forced discharge for a duration equal to its rated capacity divided by the initial test current (in amperes).

3. Requirements

The test is passed if the primary or rechargeable battery shows no disassembly or fire during the test and within 7 days after the test.