In early August 2016, Samsung Electronics enjoyed a prominent position in the global smartphone industry. It was poised to expand its footprint with the launch of an innovative flagship product. The Galaxy Note7, with its unique sleek form factor and industry-leading features such as its color display, had been highly anticipated by industry watchers, bloggers, and consumers worldwide for months before it hit the shelves.
By the end of that month, though, reports of Note7 incidents began to surface. This precipitated a global recall, after which Samsung quickly identified the problem: a battery short circuit caused by a deflection of the negative electrode. CT and X-ray scans revealed that the “jelly roll” (a design used in most cylindrical, rechargeable batteries) was compressed in the battery pouch, which weakened the separator between the two electrodes, creating multiple paths to short circuit. In order to provide replacement Note7 devices, Samsung engaged a secondary supplier — one that had provided a portion of the original Note7 batteries globally without incident. This supplier confirmed that they could safely meet the full demand for the Note7 replacement devices worldwide. However, the replacement battery soon experienced a second, distinct failure caused by abnormally high burrs on the positive electrode tab due to ultrasonic-welding defects.
Ultimately, Samsung withdrew the Note7 from the market less than two months after its launch. Industry reports estimated Samsung lost some $10 billion in sales.
Almost as quickly as the recall process played out, Samsung implemented a safety-management program unparalleled in its scope and size for the mobile industry. Augmenting existing battery tests and creating new levels of testing, Samsung developed a holistic quality and safety framework known as the 8-Point Battery Safety Check. Samsung instituted these inspection and review protocols across both its internal and its battery suppliers’ quality assurance processes — from the production of the individual components that make up the device itself, through the process of putting those components together and assembling the phone, to the very end, when the completed device was subject to additional tests.
The electronics giant also complements this testing regime with an independent Battery Advisory Group comprised of four experts — three from academia and one from the industry — who review Samsung’s processes and its responses to issues related to battery materials, design and dynamics.
“We have made significant investments in order to cast the widest possible net,” in finding solutions, says Justin Denison, senior vice president, Product Strategy and Marketing at Samsung Electronics America. The company has custom-built mass-scale testing facilities, which allow engineers to seek out potential issues or faults during production and validate the quality and safety of devices before they are released. Samsung is not only achieving its primary goal of boosting product quality, but is elevating the way the entire industry manages quality control.
Samsung’s enhanced safety program includes more testing throughout the production chain, including increased integration with its suppliers' testing processes. It is now using larger sample sizes, in some cases testing devices and batteries in lots exceeding 100,000 units.
Samsung also undertook a far-reaching initiative aimed at increasing its ability to mitigate failure risk. This complex project has increased the company’s ability to systematically and comprehensively detect battery defects before they reach consumers. More importantly, it has also created an immense volume of data on the phenomenon of smartphone battery failure itself. In other words, their scale of operations has provided Samsung with an invaluable tool that can help it accurately predict and proactively mitigate production issues yet to come and share those findings across the industry.
Samsung’s battery challenges were set against a smartphone industry backdrop of growing speed and complexity. This production environment places extraordinary pressure on all participants throughout the supply chain — which is amplified by the fundamental rules of energy and material science, including the constant tension between the density of a battery (the composition of electrode and other active materials in a lithium-ion battery) and its power. Gerbrand Ceder, professor of Materials Science and Engineering at the University of California Berkeley and a member of Samsung’s Battery Advisory Group, has stated that, while batteries don't have a direct equivalent to Moore’s semiconductor law, the average power of a smartphone battery has effectively doubled over the last decade, to an average of 700 watt hours per liter.
An Unsurprising Surprise
None of the above factors are strictly the cause of the Note7’s battery failures, either in isolation or in concert. Indeed, this constellation of industry and technical dynamics has been a constant for all device manufacturers for some time. “Fault management can be addressed one of two ways: you can either create a zero-fault environment … or design your operating environment for failure, and vigorously fix designs and processes when failures are caught,” says Ceder. He goes on to admit zero-fault conditions are “practically impossible to achieve.” This is even more so in a production environment as large as Samsung’s or that of other major producers.
Samsung responded to the challenge by further enhancing their quality assurance processes —casting a wider net, and improving systems to detect and catch those failures. This has meant both designing new and enhanced tests and increasing the sampling of devices tested, as well as folding in the macro-view of the Battery Advisory Group.
More Tests, More Collaboration
Samsung’s efforts represent significant investments in time, material, and production costs.
“At Samsung, we strive for meaningful product innovation to meet the growing needs of consumers — but what our investigation taught us is that we have to innovate in our processes as well. Whether it’s in design, and engineering, or quality assurance, we’re constantly looking for areas in which we can improve,” says Denison.
Samsung was able to leverage the significant change-management expertise to enhance its safety management processes. Samsung’s 8-Point Battery Safety Check not only institutionalized a series of reviews throughout the supply chain but also improved multiple tests involving large-scale sampling of completed devices, which appears unique to the industry.
Five of these tests, including a durability test subjecting batteries to punctures and overcharging, were already processes as part of Samsung’s safety regime, but have now been enhanced with increased frequency and/or additional testing stages at different phases of the production process.
Three entirely new battery stress tests were also added: a charge and discharge test conducted at each production stage; an accelerated usage test involving, “intensive usage scenarios,” says Denison; and a total volatile organic compound test.
These eight tests take place across three distinct stages. The first stage is focused on ensuring that the incoming quality of components meets Samsung requirements. Six tests are performed on all incoming lots of batteries, which is typically anywhere from 10,000 – 15,000 units, and half of the tests conducted at this stage are destructive tests. If even a single failure is observed during this testing, the entire lot of batteries will be thrown out. Samsung and the supplier then stop the assembly process to evaluate the root cause of the battery issue.
Once the battery lot is approved for production, additional testing is performed on the batteries and devices as they move through the phone production process. Batteries are rejected if they fail the tests. Samsung also conducts a completed device check after the initial production phase, which includes a massive charge and discharge test and accelerated usage test. Samsung then conducts mass-scale testing, collecting vital data throughout the process.
Samsung’s quality control and testing processes are increasingly linked to those of its battery suppliers and subcontractors. A fundamental component of the 8-Point Battery Safety Check framework is a reliance on deep collaboration between Samsung’s incoming quality control teams and those of its suppliers.
Samsung’s efforts—testing at a level of quality and scale far beyond industry requirements—have culminated in what may be the world’s largest collection of data on in-device failure and performance issues. Part of this effort is tighter collection and data management methodologies.
“Every single battery that flows through our supply chain has a QR code [quick response code, or bar code] on it, to allow us to monitor the quality and performance of each battery going through our device production process,” which is then added to a massive database, says Denison. Additionally, the scale of the testing allows for a data pool that could transform a wide detective net into a predictive tool.
“There is an unprecedented amount of information and insight that can be generated from the manner and scale with which Samsung is analyzing in-device charging activities,” says Ceder.
Product and component failures are inevitable in any manufacturing process. Producing in large numbers allows for the ability to replicate incidents. With smaller production volumes, it may be more difficult to distinguish between legitimate issues and one-off failures. In the wake of the Note7 recall event, though, Samsung turned the size, scale, and complexity of its supply chain into an asset.
To simply build a better haystack needle-detecting engine is not in and of itself revolutionary, or even truly possible. By increasing the number of tests and the scale of the related sample sizes, however, Samsung has developed an innovative solution for failure mitigation that will have massive ramifications across the entire industry. Samsung’s response has created a quality control collaboration platform in which the entire industry may participate and from which it may benefit.
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