UN38.3 - Why do lithium batteries need UN38.3?
What does UN38.3 mean?
UN38.3 is the prevailing United Nations standard that lithium batteries must meet to receive certification for safe transport. Lithium batteries un38 3 must undergo a rigorous series of tests performed by an approved independent testing laboratory to ensure they do not rupture, leak, disassemble, or catch fire.
Why do we need UN38.3
DOT/UN38.3 Tests are performed on all lithium batteries being shipped. The test standards comply with the United Nations (UN) test manual and US Department of Transportation (DOT) regulations. DOT/UN38.3 is not only a requirement in the United States but has also been adopted as an international standard because lithium batteries may be transported across international waters and borders.
What is the test object of UN38.3
The test object of UN38.3 is Lithium cells and Lithium batteries, which are mainly composed of negative electrode materials, electrolyte and positive electrode materials. The chemical activity of the cathode material graphite in the charging state is close to that of lithium metal, and the SEI film on the surface decomposes at high temperature.
Why test lithium batteries
Lithium batteries contain the metal lithium in their chemical composition. The metal has the extremely high energy density and low discharge rate that consumers have come to expect from their electronic devices.
Unfortunately, the metal is very unstable and reactive. When the temperature rises too fast during charging and exceeds the battery’s melting point, the chemical composition of lithium batteries goes into thermal runaway. This can cause lithium batteries to emit dangerous hot gases or build them up to the point where the battery pack can explode or catch fire.
All lithium batteries must be equipped with a battery management system (BMS) in the battery pack to ensure thermal runaway without fail-safe features. BMS will equip the battery with electronic protection circuits and various other safety mechanisms to monitor the battery during charging and discharging. If a high surge is detected that may cause the un38 3battery pressure to exceed the safe limit, the protection circuit will perform various tasks, such as safely discharging gas at a controlled rate. It will also cut off the current if the temperature exceeds a specified threshold, and it will also cut off the current if the battery over discharges, so the voltage will not fall below the recommended 2.5V per cell.
Lithium batteries are considered dangerous goods because they fall under the United Nations Category 9 dangerous Goods classification. As a result of this classification, tests are carried out to ensure that lithium batteries and their protective circuits are designed and manufactured to meet safety requirements. The tests will also check for any ventilation, leaks, flames, or other hazardous conditions. The test applies to all types of lithium-based batteries but does not require other batteries that do not contain lithium metal.
Type of test for lithium batteries
Lithium batteries will be tested according to mechanical and electrical requirements. These tests are carried out at all points in transit, whether the battery un38 3 is moving from supplier to manufacturer, manufacturer to retailer, or retailer to distributor. It also applies during product returns.
Lithium batteries are self-tested both outside the product and when installed in the product. These requirements also apply to lithium batteries used in the field, when they are transported outside their original packaging, and for each type of transportation process: air, rail, road, or sea.
What is UN38.3 test report?
3 refers to Section 38.3 of Part 3 of the “United Nations Manual of Tests and Standards for the Transport of Dangerous Goods” specially developed by the United Nations for the transportation of dangerous goods, which requires that lithium batteries must be subjected to highly simulated, high and low-temperature cycles.
DOT/UM38.3 contains 8 lithium battery tests
T1-Altitude Simulation: A low-pressure test that simulates the unpressurized cargo area of an aircraft flying at an altitude of 15,000 m.
T2-Thermal Test: A temperature test that evaluates extreme temperature changes. The battery can be stored at -40°C to 70C° C for 6 hours for several cycles.
T3- Vibration test: A vibration test that simulates the motion the battery undergoes during transportation.
T4-Impact test: An impact test that also simulates the vibration to be experienced during transportation.
T5- External short circuit test: The external short circuit test simulates the short circuit that occurs in the battery or at the battery’s external terminals.
T6- Impact test: Impact test to simulate the impact of lithium batteries. For cylindrical batteries smaller than 30mm, impact tests are carried out on the battery housing.
T7- Overcharge test: The overcharge test simulates the overcharge of rechargeable or secondary batteries.
T8- Forced discharge test: The forced discharge test simulates the forced discharge condition of the battery.
All of the above tests were performed on primary and secondary batteries except the T7- overcharge test. The T7 test was performed on secondary and rechargeable batteries only. The T8 forced discharge test is performed only on the primary battery and the secondary battery. Accredited organizations and testing laboratories can perform these tests and provide certification. Organizations can obtain ISO17025 certification to ensure that their testing processes meet all national and international standards. Battery test certification must be updated in some cases, such as when the battery design or product design changes before the final shipping process.
What is the T1 → T5 test in the UN38.3 standard
However, the T1 → T5 test in the UN3813 standard tests the same sample in sequence. The previous test may have a negative impact on the next test, resulting in failure to pass the test. If the lithium battery submitted for inspection is tested for T1 → T5 in the UN 38.3 standard, there will be one item unqualified.
Why do lithium batteries fail to pass the UN3813 test
The previous test may have a negative impact on the next test, resulting in failure to pass the test. If the lithium battery submitted for inspection is tested for T1 → T5 in the UN 38.3 standard, there will be one item unqualified. Enterprises need to re-test UN3813 standard after process improvement, which will greatly extend the testing cycle.
Transport of lithium batteries
DOT/UN38.3 requirements set limits on the number of lithium batteries a manufacturer, distributor, or retailer can ship on an aircraft at one time. These limits will be based on the amount of lithium contained in the lithium-ion battery or the watt-hour rating of the lithium-ion battery. The following information applies only to the net number of batteries not combined in the same package.
Lithium metal batteries less than 0.3g: no quantity limit per package.
Lithium metal batteries containing more than 0.3 g but less than 1g: 8 cells each package.
Lithium metal cell batteries weighing more than 0.3g but less than 2g:2 batteries each package
Lithium-ion batteries/batteries rated less than 2.7Wh: no limit for each package.
Lithium-ion batteries/batteries rated at more than 2.7Wh but less than 20Wh: 8 cells each package.
Lithium-ion batteries/batteries rated at more than 2.7Wh but less than 100Wh: 2 batteries each package.
How do you get UN38 3
Lithium batteries must undergo a rigorous series of tests to meet UN38.3 performed by an approved independent testing laboratory. Batteries must not rupture, leak, disassemble, or catch fire to receive certification. There are eight tests that that must be passed for a lithium battery to receive the certification.
Lithium and lithium-ion batteries undergo extensive testing to ensure that they can be safely used in specified products and applications. Due to testing requirements, it is usually necessary to send a certain number of packages (16) for testing. Testing can take as long as four to six weeks. We need to consider these factors, development costs, and the expected time expectations for a product to market when developing a custom battery pack. If you want to know more about lithium battery, Please contact Maxworld Power.