WHAT WE LEARNED FROM 100M SMARTPHONES
Tesla’s market valuation hit today $225 Billion, more than the valuation of any other auto manufacturer, highlighting the importance of the lithium-ion battery to our economies.
The battery is the product differentiator for electric vehicles, stationary energy storage and many consumer devices. Each category is pushing the specifications of the battery — and they all share similar themes: more charge capacity, faster charging, battery longevity, less weight, less cost, and absolute safety!
Many manufacturers shy away from sharing lessons learned from deploying batteries in large volume. In some respect, it is understandable — the battery is a competitive advantage. But by keeping opaque, the end user suffers. At Qnovo, our customers have deployed our battery management solutions on well over 100 million smartphones. Along the way, we learned a few important things. I will share here two relevant observations:
1. Optimizing between performance, cost and safety needs smart software:
Innovation in materials is important but increasingly insufficient to give end users the experience they deserve. The battery has grown from nearly 1,500 mAh in early smartphone models (the original iPhone’s battery capacity was 1,400 mAh) to a whopping 5,000 mAh in 2020 models to accommodate 5G networks. With the increase in capacity and energy density comes a slew of design headaches leaving little margin for error: maintain the battery’s longevity; provide fast charging; minimize battery swelling, all at once. Optimizing between strict performance specifications, pressure to source from lower cost battery manufacturers in China, and absolute safety is no longer exclusively in the realm of materials. Instead it demands battery intelligence and smart software.
Similarly, electric vehicles are under similar if not tighter constraints. Longer driving range, faster charging, exposure to extreme temperatures, presence of minute manufacturing defects, and immense cost pressures make battery design a difficult task. It is no surprise that auto OEMs now rank battery intelligence software as critical to their systems. OEMs are also becoming more involved in the design and manufacturing of batteries. For instance, Apple designs its own batteries in Cupertino, and BMW invested €200 million in a battery cell competence center in Munich.
So what can intelligent battery management software do? Here’s one representative data point from our results. Our average longevity over 100 million smartphones shipping with our solutions is 1,900 cycles at 25 °C, and an incredible 1,300 cycles at the punishing temperature of 45 °C. Otherwise, an average smartphone will last between 500 and 1,000 cycles. Increasing longevity raises the available capacity and use time, improves the battery’s health and safety, reduces its swelling to make thin smartphones, and gives the end user a far better overall battery experience.
2. Improvement in safety requires more predictive smart software:
The cell voltage rose from a safe 4.2V in early smartphone models to 4.47V in the newest 5G models — needed to add more energy to the battery. At these high voltages, the margin of safety is razor thin: battery swelling, extreme temperatures, user abuse, minute manufacturing defects, fast charging all contribute to an elevated risk of battery failure or fire!
Data from the field indicate that unsafe battery failures account for 10 to 20 incidents per million devices (measured as parts per million, or ppm) — these incidents lead to property damage or personal injury to the user. Any industry with failure rates in ppm can laud its accomplishments; but ppm levels are grossly inadequate for batteries. There are approximately 1.5 billion new smartphones sold worldwide every year. At ten ppm, there are 15,000 unsafe smartphone incidents annually! This is not acceptable.
It is incorrect to assume that the industry can improve battery failure rates solely by tightening battery manufacturing processes. It is true that battery manufacturing defects contribute to failure — but defects are not the only reason why a battery may catch fire. Improper operation, poor smartphone design and specifications, and user abuse can all lead to premature unsafe failure. Battery manufacturers, especially in China, are also reluctant to add more controls and cost to their manufacturing processes — battery manufacturing remains an industry with thin financial profits at best, or more often endemic losses.
Let’s step back for a moment and briefly examine a different industry: lens making. Historically, making high quality lenses for photography was a specialty left to a few companies in Germany and Japan, e.g., Leica, Nikon or Canon. They excelled at their manufacturing prowess and accuracy. Then innovation struck in the form of cameras embedded in smartphones. These used cheap plastic lenses but corrected for their optical deficiencies using software. Images from modern smartphone cameras can surpass the quality of those from expensive DSLR cameras. The camera industry showed that it can substitute manufacturing accuracy with computation, the latter being enormously less costly.
We use a similar philosophy to improve the safety of batteries. We recognize that manufacturing defects are part of building batteries. We use predictive algorithms to identify these defects long before they become a safety hazard, then manage the operation of the battery to reduce the risk of a failure. The result is that there were zero unsafe failures over 100 million smartphones in the field.