Power Electronics

Lithium (Ion) Battery Safety and Required Regulatory Testing

Lithium non-rechargeable and rechargeable batteries have seen their usage soar since the late 1990s. Millions of products from laptops to cell phones to watches, and more recently electric/hybrid vehicles, contain these batteries. In fact, some industry experts forecast that global growth in Li-ion batteries will exceed 400% in the next four years alone (2011-2015).

With the increase in applications for these batteries, it has become apparent that there are some safety issues that need to be addressed. Batteries can catch fire if they are damaged, exposed to high temperatures (exceeding 290°F) or packaged incorrectly. Lithium-ion battery thermal runaway reactions can exceed 1,220 °F, the melting point of aluminum, a key material in airplane construction. Lithium-metal battery fires are far hotter yet.

The figure shows the remains of a UPS cargo plane that was carrying thousands of lithium batteries. It crashed near Dubai in the United Arab Emirates, killing both pilots. The accident is still under investigation, but preliminary reports indicate that investigators have focused much of their attention on the batteries, that may have started a fire on board the plane.

As a result, the organizations that now govern the transportation of lithium and Li-ion batteries and cells include the International Civil Aviation Organization (ICAO), the International Air Transport Association (IATA) and the International Maritime Dangerous Goods Code (IMDG). In addition to international requirements, domestic regulations must be followed. The United States Department of Transportation (DOT) regulates the shipment of lithium and Li-ion cells and batteries domestically under part 49 of the Code of Federal Regulations, and UN/DOT under Section 38.3.

To properly address the safety issue, and decrease the failure rate, new standards have been instituted. The required compliance to the new IEC 62133 Standard and testing needs to be completed before the battery products can be shipped, and domestic shipments must be tested in accordance with UN 38.3. Compliance is required by May 1, 2012.

This international standard specifies requirements and tests for the safe operation of portable sealed secondary cells and batteries. Cells and batteries need to be designed and constructed so that they are safe under conditions of both intended use and reasonably foreseeable misuse. Cells and batteries must undergo the following tests (see Table 1) to be certified to this standard.

For transportation purposes, cells and batteries must be classified and tested by the following criteria for Class 9 hazardous materials (see Table 2).

Related Articles:

Power-Monitoring Circuits for Battery Performance

Protecting Lithium-Ion Batteries for Electric Vehicle Applications

Proper Care Extends Li-Ion Battery Life

Detecting Internal Lithium-Ion Cell Fault Development In Real Time

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