Samsung Puts 8-Point Battery Check Front and Center After Note7 Problems

The battery safety checklist includes a durability test for overcharging, nail punctures and extreme temperatures; a visual inspection using standardized and objective criteria; an X-ray for abnormalities; a charge and discharge test; a volatile organic compound test for leakage; a dissembling test to check the quality of battery tab welding and tape conditions; an accelerated usage test to mimic consumer use; and a test to detect a change in voltage throughout the manufacturing process, Samsung said.

The company is also in the planning stage for a multiple-layer safety protocol that will implement "strict safety standards on every element of the company's devices.” Measures include a battery safety design standard for safe operation and materials; a new hardware design that includes brackets to protect batteries; and an improved software algorithm for governing temperature changes, current fluctuations and charging duration, it said.

DJ Koh, president of Samsung’s mobile communications business, blamed batteries from two different unnamed companies for the problems, and acknowledged Samsung provided the “target for the battery specifications” for the Note7. “We are taking responsibility for our failure to ultimately identify and verify the issues arising out of battery design and manufacturing process prior to the launch of the Note7,” said Koh, and took corrective actions “to ensure this never happens again.”

The manufacturer is putting in place a battery advisory group comprising academic and research experts "to ensure the company maintains a clear and objective perspective on battery safety and innovation." Members include Clare Grey, University of Cambridge chemistry professor; Gerbrand Ceder, UC-Berkeley professor of materials science and engineering; Yi Cui, Stanford materials science and engineering professor; and Toru Amazutsumi, Amaz Techno-consultant CEO.

Samsung’s investigation -- along with those of third-party expert organizations UL, Exponent and TUV Rheinland -- examined assembly, quality assurance testing and logistics at a testing facility where 700 Samsung researchers and engineers replicated incidents with more than 200,000 assembled Note7 devices and more than 30,000 batteries, Samsung said.

The CPSC issued the first U.S. recall for the Note7 Sept. 15, saying the “the lithium-ion battery in the Galaxy Note7 smartphones can overheat and catch fire, posing a serious burn hazard to consumers.” After Samsung’s move to a new battery supplier in the next round of devices also resulted in overheating batteries, the CPSC issued a second recall for the fire-prone devices on Oct. 13. The CPSC said Samsung received 96 reports of batteries in Note7 phones overheating in the U.S., including 23 new reports since the initial Sept. 15 recall announcement. Samsung received 13 reports of burns and 47 reports of property damage associated with Note7 phones, it said in October. The recall included about 1.9 million phones, including the 1 million recalled on Sept. 15, said the agency.

Samsung and the commission stepped up efforts to contact Note7 customers in an “expanded” recall outreach to get all Note7 devices out of consumers’ hands as soon as possible after Samsung’s decision to stop Note7 production permanently in mid-October (see 1610130044). “Consumers should immediately stop using and power down all Galaxy Note7 devices, including Note7 devices received as replacements in the previous recall,” the CPSC said in an email (see 1610130044), part of a “globally coordinated announcement” with Samsung.

The recall led to an FAA ban on the devices on aircraft and the unusual step of notifying passengers of the ban during U.S. flights’ preboarding safety announcements. The ban is still in place, but the requirement of the preboarding announcement was lifted earlier this month (see 1701110037) due to the “high degree of public awareness.” That Samsung had “successfully recalled” more than 96 percent of the Note7s shipped in the U.S. was evidence of “the awareness of the ban,” the FAA said.

UL test findings revealed Monday showed different causes for short circuits in the batteries from manufacturer A, which supplied the phones involved in the first recall, and manufacturer B, which supplied batteries for phones in the second recall. The issues were specific to the batteries, said the UL report.

UL attributed a likely major failure mechanism for company A to a combination of deformation at the upper corners of the battery in combination with a thin separator and repeated mechanical stresses due to cycling, which would cause a “higher possibility of separator damage leading to an internal short circuit between aluminum and copper foil at the corner." For company B, the likely failure mechanism included missing insulation tape, sharp-edged protrusions on the battery tab and a thin separator, all of which could have led to an internal short circuit between the cathode tab and anode that caused overheating and fire, UL said.

A lithium-ion battery section on the UL website written last summer warns consumers about causes of malfunctions and what consumers can do to avoid a malfunctioning battery. Factors contributing to malfunctions: lack or shortcoming of safety features; lack of stringent cell and battery manufacturing and quality control; mismatch of battery and charger performance capabilities; device performance and environmental issues; and the history of how a device was used.