By: Jim Green
Global Business Manager, Energy Storage
Recent safety recalls of portable devices and computer batteries point out the challenges that manufacturers face in an environment where consumers continually demand smaller devices, with higher power, longer run time, and lower cost. Manufacturers strive to make these improvements without sacrificing safety, quality and manufacturability.
The vast majority of manufacturers in today’s competitive environment are reputable companies who expose their designs to a wide range of test programs in an effort to produce safe, quality products. Product development testing, certification to industry standards, supplier component evaluation, and end product quality assessment are conducted to ensure that the design meets performance, durability, reliability, and safety specifications. This detailed and thorough process provides confirmation that end products are manufactured to consistently meet the design guidelines with extremely low defect rates.
Specific to the certification process, a manufacturer will submit product documentation and a limited number of samples to a Nationally Recognized Test Laboratory (“NRTL”) such as CSA Group. These samples will be evaluated against the applicable standards starting with a review of the construction and followed by the certification test program.
The construction review will analyze the design to confirm that it meets general safety considerations for normal use and what CAN/CSA-E62133:13, IEC 62133, and many other standards identify as “reasonably foreseeable misuse”. Standards do not predict the wide variety of abuse to which products might be subjected, so more aggressive abuse tests may be a part of the manufacturer’s product development testing.
For batteries, examples of what may be assessed in the construction review include the insulation and wiring, venting, terminal contacts, the methods used for temperature, voltage, and current management, and the assembly of the cells into the pack. Where applicable, internal component certification documents, a manufacturing quality plan, an operator’s manual, and a failure analysis such as a Failure Modes and Effects Analysis (FMEA) will also be assessed.
Next, the test program will begin by conducting any preconditioning of the test samples that might be required by the standard. For batteries, this might include charge/discharge cycling for a specified duration. The test program will then subject the battery to a series of tests, typically designed to place the battery under mechanical, electrical, and/or environmental stress. The test standard will specify the criteria for failure of each test, which might be fire or explosion in the case of a lithium ion cell for example.
Assuming all the support documentation, the construction review, and the test results are acceptable, the manufacturer will be granted a limited right to use the agency’s certification mark with the certified product. The manufacturer will be subject to periodic factory inspections, which are designed to audit whether a company is manufacturing their product exactly as specified in the certification. These inspections are required to help identify manufacturers who might substitute less expensive, non-certified components into their manufacturing process as a cost saving measure. Other reasons for inspection may include helping to detect issues such as components from new suppliers or minor design changes which might not be in the certification file. The manufacturer and certification agency will then work together to make sure the file is up to date and that any changes requiring further certification tests will be reviewed.
Even with these thorough measures in place, a reputable manufacturer could still be subject to a product failure and recall. Manufacturing defects will inevitably occur during mass production. A robust design that is engineered to fail in a non-hazardous manner, combined with a well-managed supplier and production quality system, will help minimize the risk of failures and identify defects before they reach the public.
Companies may hire third party testing partners to conduct ongoing quality testing and evaluation programs. These may include procurement of samples from retail shelves to ensure a random sampling of products that have been subjected to a realistic transportation and handling environment. Additional testing of supplier components may also be conducted through independent labs to increase the robustness of the supplier quality program.
When a defect occurs that is undetectable during the manufacturing process, failures in the field may occur. Manufacturers will then work with their customers, their internal quality departments, and potentially government safety agencies to isolate the batch of products which might carry the defect. Third party labs may again be consulted to assist with failure analysis, conduct a larger sample of testing to determine failure rates, or to confirm that design modifications to address the failure are successful. Depending on the hazards which might occur if a product fails, the manufacturer may request that a customer return the product or dispose of it for a refund or replacement. In some cases, the manufacturer may voluntarily issue a safety recall of all potentially effected products, or may be ordered to by the government safety agency. At this point, significant effort will be made to remove the product from the market.
Product safety is a complicated process. Manufacturers go to great lengths to prove their designs and production processes, especially with potentially hazardous products such as batteries and energy storage systems. Ensuring a product is compliant with applicable industry standards and carries a certification mark issued by a NRTL such as CSA Group is a critical step in this process.
Jim Green serves as the Global Business Manager for Energy Storage and can be reached at [email protected].