Last week Samsung suffered the ignominy of having to issue a global recall of all 2.5 million Note 7 phablets that it had recently shipped, due to battery problems.

Samsung issued a statement saying, “Samsung is committed to producing the highest quality products and we take every incident report from our valued customers very seriously. In response to recently reported cases of the new Galaxy Note7, we conducted a thorough investigation and found a battery cell issue. To date (as of September 1) there have been 35 cases that have been reported globally and we are currently conducting a thorough inspection with our suppliers to identify possible affected batteries in the market. However, because our customers’ safety is an absolute priority at Samsung, we have stopped sales of the Galaxy Note7. For customers who already have Galaxy Note7 devices, we will voluntarily replace their current device with a new one over the coming weeks. Instructions on the replacement process will be shared next week.” Samsung has now started to make those exchange instructions clearer, with UK owners able to exchange their devices from 19th September.

A lot of questions still remain unanswered and Samsung has understandably kept quiet in response to requests for an interview, but some facts are emerging. Samsung’s own battery division (Samsung SDI), which accounts for approximately two-thirds of the batteries in the Note 7, appears to be at fault here, while the batteries from Samsung’s second-source supplier, Hong Kong based Amparex, appear to be fine. It's not clear yet whether it's a manufacturing issue with one batch of material, or a production assembly problem, human error, quality control, etc. Other areas that may have been a factor are the power management IC and the charger. The Note 7 uses a  fast charging technology called Quick Charge 2.0, which will reportedly charge the 3,500 mAh battery from 0% to 50% in 25 minutes. I’m slightly surprised that Samsung didn’t opt to use Qualcomm’s newer Quick Charge 3.0 technology which has even faster charging times. Perhaps Samsung had already identified battery failures during pre-production using Quick Charge 3.0 and decided to play safe with the older standard. Either way the batteries should not have short-circuited in the way that they did.

My gut feeling is that Samsung has done the right thing to issue a recall and halt sales until a solution is found. You might say that 35 known failures out of the 2.5 million devices sold since August 19th (0.0014% failure rate) is a drop in the ocean, but when it comes to explosions, fires and safety issues, this is 35 too many. Samsung has a reputation to uphold and problems like this don't help, especially at this time of year when Apple is about to launch its iPhone 7. Samsung was hoping to steal Apple's thunder with the Note 7, but that seems to have backfired and according to some media sources Samsung is going to lose an estimated $1 billion as a result of this problem.

One question I have been asked is why haven't the hazards of Li-Ion batteries been ironed out over the last 20-25 years? It's a simple question with a complicated answer. If battery manufacturers were focussed only on improving the safety of Li-Ion cells then they would have succeeded years ago and we wouldn't have been talking about these explosions at all. However, battery manufacturers are being pushed hard by their customers and are constantly searching for ways to increase the volumetric energy density of Li-Ion cells (cram more energy into the same space), as well as making the prismatic cells thinner to fit inside the thinner smartphone form factors that have been the trend for the last 10 years. To gain improvements of even a few per cent per year means pushing everything as close to the limit as possible, without compromising safety. 

Unfortunately battery chemistry improvements have not been able to keep pace with improvements in other areas of smartphone development: displays are bigger and higher resolution, smartphone processors are unimaginably more powerful than they were 10 years ago, and smartphone vendors are adding more sensors and functionality into every new flagship model. Meanwhile on the Li-Ion battery front, incremental improvements have been made in all key areas of anode material, cathode material and electrolyte. I have seen announcements from numerous companies over the last 10 years making wild claims about having developed a fantastic new battery chemistry that will solve all of our problems, but none of them has lived up to the hype, so we are still in the situation of relying on evolutionary development until a revolutionary battery technology eventually (hopefully) appears. Two rechargeable "battery" technologies that are looking promising in the short term are super-capacitors and new variants of Lithium-Metal batteries. Both have their advantages and disadvantages over existing Li-Ion cells, and we will write more about them in the coming months.

Stuart