Mobile Device Fires: Their Cause and Prevention

PDF version of this report
You must have Adobe Acrobat reader to view, save, or print PDF files. The reader
is available for free

Mobile Device Fires: Their Cause and Prevention

by Michael Gariffo

Docid: 00021057

Publication Date: 1701

Report Type: TUTORIAL


For more than a decade now, the mainstream media would occasionally run
a story about a fire seemingly caused by an overheating or
exploding mobile device, typically a smartphone or other mobile phone.
These incidents were generally few and far between and were always
treated as strange, even unexplainable flukes. Some even
believed them to be solely the result of shoddy user modifications or
aftermarket repairs gone wrong. For the most part, few ever took a deeper dive into the
cause behind these rare combustions. That all changed in
2016 when Samsung’s Galaxy Note 7 smartphone became the center of a quite
literal media firestorm due to its alarming tendency to catch fire
or explode. For the first time, mobile device fires were fully
exposed in the mainstream media spotlight. People suddenly feared
that something as innocuous as a smartphone could become a small
bomb they were unknowingly carrying around in their pockets. While the reasoning behind these fires had already been
investigated extensively, this was the first time the public demanded
answers. This report attempts to provide those answers by
examining how the batteries powering our devices work, how they can fail so
badly that they literally explode, and what can be done to prevent
something like this from happening.

Report Contents:

How Batteries Work

[return to top of this report]

First, it is important
to lay the groundwork to ensure that all readers understand the basic
composition of the types of batteries being used to power modern mobile devices.
It is also important to begin by noting that this report will not explore the
various types of batteries that are used in the world today. Technologies such
as lead-acid batteries, typically used in automobiles, or nickel-metal hydride
batteries, typically used for rechargeable AA or AAA power packs, are all still
in use, but have proven to be impractical or inferior for powering our modern mobile devices. Instead, nearly all manufacturers of smartphones, feature phones, laptops, tablets, and even many electric vehicles
have turned to lithium-ion batteries. Often referred to as li-ion batteries, these cells can be found in the pocket or purse of just about
ever mobile device user in the world.

Figure 1. A Diagram of the Charging and Discharge of a Li-Ion Battery

Figure 1. A Diagram of the Charging and Discharge of a Li-Ion Battery

Source: Royal Society of Chemistry

As you can see in the diagram above, lithium-ion batteries function in the
same way as most
rechargeable batteries: a cathode (also known as a positively charged
electrode) – in this case, intercalated lithium – is
suspended alongside an anode (or a negatively charged electrode) – in this case graphite – within a sealed space
containing an electrolyte. This setup results in a chemical reaction that
strips electrons from the positively charged cathode and allows them to flow to
the negatively charged anode. This flow of electricity is then output via the
battery’s terminals and is provided to the device it is powering. The entire
process is essentially reversed when a rechargeable battery like a li-ion cell
is being recharged, with electricity flowing into the cell and restoring the
electrons that had previously been stripped from the cathode.

It is important to remember that batteries
are, first and foremost, storage devices for energy. Whether you are referring
to a primary battery (the non-rechargeable variety) or a rechargeable cell like
the lithium-ion one pictured above, the sole purpose of a battery is to store
and contain energy. This energy is designed to be held until needed, at which
point it is provided at a metered rate via the battery’s terminals in the form
of electricity. In order for this to occur correctly, batteries must be
manufactured to a very high standard. A short circuit (when two parts of a
battery or electrical system unintentionally touch each other resulting in an
unwanted energy discharge) can be caused by the slightest variance in production
tolerances. Similarly, worn or damaged batteries can suffer a short circuit or
similar failure due to their original design having been compromised by time,
heat, or impact. Most units take these dangers into account
with safeguards in place to prevent or curtail any unwanted discharges.

However, as users come to expect smaller and smaller devices with longer and
longer battery lives, mobile device makers are researching how to provide the greatest "power density" they can in the smallest package
possible. Lithium-ion batteries have become popular with manufacturers due to
a very high power density compared to their relatively little weight. Conversely,
lead-acid batteries (typically found in gas-powered automobiles) have a low
power density, which is why they so large and heavy when compared to something
like a smartphone battery. This high energy density, as well as the ability to
withstand hundreds or thousands of recharge cycles, makes lithium-ion batteries
ideal for use in mobile devices. Unfortunately, these same characteristics are can
also be exactly what makes them dangerous when things go horribly wrong.

Battery Fires

[return to top of this report]

Fires caused by lithium-ion
batteries are very, very, very rare. This technology has been in use for longer
than most people realize and has been powering cell phones since the days of
the earliest flip phones. Even in a nightmare scenario on on the scale of the
Samsung Galaxy Note 7 fiasco, only 35 cases of devices overheating or catching
fire were confirmed out of the more than three million devices manufactured and
shipped by Samsung during the Note 7’s short lifespan.1
This means that, even during one of the worst manufacturing blunders in history, 
the odds of a device catching fire due to a battery defect were about 1 in
86,000. Although these odds can't be considered safe, the instance of Note 7
problems was nowhere near as common as another controversial product that brought the
dangers of lithium-ion batteries to the forefront: the hoverboard.

The hoverboard is a self-balancing,
two-wheeled platform that users can control by leaning in the direction they
want to go or twisting the two halves of the platform to turn. The item
quickly became one of the hottest gifts of the 2015 holiday season and sold
more than 500,000 units in the US alone. However, more than 100 fires were
reported as a result of faulty batteries in these personal vehicles.2
While this is far in excess of the rate at which Note 7 batteries were found to
combust, it is important to note that many of these hoverboards were almost
universally found to be
extremely poorly manufactured, suffering from almost no quality control, and with many of
the safety features typically found in rechargeable devices missing. They were,
in no way, exemplary of the extremely tight tolerances to which most smartphone
and mobile devices li-ion battery cells are made.

Yet, despite quality control measures, things can obviously still go wrong. The reasons can vary but
are almost always the result of
one of two factors: a manufacturing defect or post-sale damage to the power
cell.3 While the reason for the fault may vary, the actual root cause
of the fault is essentially always the same, a short-circuit followed by an
electrical or thermal fault within the power cell. The results of this unwanted contact can vary from a mild
power increase to the
battery’s self-discharge (the amount of power unintentionally lost by the cell,
rather than being provided to the device it is powering) to a full-on
conflagration. In the latter case, the fire is triggered by what is know as a
"thermal runaway" event.4 Like most short circuits, those that occur
in li-ion batteries produce electricity and heat. Due to the chemical composition and tight
tolerances of battery manufacturing, unwanted and unexpected levels of heat will
quickly deform the battery, exposing the unit to fracture, failure, and "rapid
disassembly." in other words, a small spark within a cell can cause a chain
reaction that causes the entire unit to overheat, resulting in the ignition of
one or more of the components within the battery.

In the case of lithium-ion cells, it is typically the lithium metal itself
that ignites and causes the most dramatic flames and smoke. These often come in
the form of a solid jet of flame at the point where the battery's outer casing
has failed, typically followed by a thick, opaque smoke as the metals and
chemicals within the battery are consumed by the flames. Contact with the air as well as moisture in the form or water being used to
douse the flames can cause lithium to combust even more energetically, making
the job of extinguishing a lithium-ion battery fire that much harder. Because of
this, it is recommended that an approved fire extinguisher be used on this type
of blaze.5 

What Started the Galaxy Note 7 Fires

The Galaxy Note 7 has come to stand as the most infamous case of
battery failure in modern electronics. Due to the extremely high-profile nature
of this catastrophe and the incredibly in-depth investigation undertaken by
Samsung to discover its root cause, the body of information available on what
causes batteries to fail has been greatly expanded within the past several
months, thanks to the 700 engineers, 30,000 Note 7 batteries, and
200,000 smartphones from which Samsung gathered data.

Figure 2. Samsung’s Testing Facility During the Note 7 Investigation

Figure 2. Samsung's Testing Facility During the Note 7 Investigation

Source: Samsung

Although Samsung’s bottom line was severely damaged by the occurrence, the
ultimate result may be that lithium-ion batteries in the future
will be safer than ever.

What did this massive investigation uncover about the root cause
of the Galaxy Note 7 fires? Interestingly, Samsung turned up not one
single cause of all the fires, but a pair of flaws that led to two ways
in which the Galaxy Note 7 batteries could fail and ultimately ignite.6
These varied depending on which of the two manufacturers created the
cells of a given battery pack. The first of
these two makers was Samsung’s own Samsung SDI. This division of the
company has made power cells for numerous Galaxy smartphones and other
mobile devices for years and was tasked with making the cells that
shipped with the initial Galaxy Note 7 devices during their first
release. When these units were found to be faulty, a second company, Amperex Technologies, was commissioned to produce new batteries for the
replacement units.7 Unfortunately for Samsung, these
supposedly "safe" replacement batteries were found to be faulty as well,
albeit for a different reason than their predecessors.

Taking a deeper look into Samsung’s investigation, we find that the batteries
manufactured by both Samsung SDI and Amperex were tightly packed cells
with almost no room for error in their design.

Figure 3. Samsung’s Diagram of the Note 7 Battery’s

Figure 3. Samsung's Diagram of the Note 7 Battery's Construction

Source: Samsung

The tightly layered cell was less than half a centimeter in thickness,
including layers of insulation tape that were thinner than a human hair.
Although this is a common design for the diminutive batteries powering most cell
phones, it begins to reveal just how little error is required for cells to
become unstable.

The specific flaw found in the case of the original Samsung SDI cells
(referred to in Samsung’s investigation as "Battery A") was a miniscule
misplacement of the layers within the "jelly roll" section of the cell. This
area, which had a curved design in order to fit the Note 7's outer case, could be damaged or manufactured with just
a slight variance, resulting in certain layers of the negatively charged anode
making unintentional contact with components they
should have been insulated from. The presence of a
longer than intended negative electrode plate (seen below) that terminated in
the curved part of the battery cell allowed for unintentional contact and
a subsequent short circuit to occur.8

Figure 4. Samsung’s Explanation of the "Battery A"

Figure 4. Samsung's Explanation of the "Battery A" Flaw

Source: Samsung

When contact between the negative electrode (or anode) and another section of
the battery occurred, it could trigger a thermal runaway
event. This subsequently could cause a small portion of the battery to melt, exposing additional
components to each other and breaching the
outer pouch of the battery cell. If this occurred, the lithium inside the pouch
would be exposed to the
outside air, producing flames, smoke, and the explosive reaction described

In what can only be described as an extremely unfortunate set of
circumstances. The units that contained the flawed Samsung SDI batteries were
replaced by new cells manufactured at Amperex Technologies (called "Battery B" by
Samsung during its investigation). While the units were now, of course, thought to be safe
and functional, an entirely different flaw arose in the second batch of
Galaxy Note 7 batteries that caused similarly disastrous results for Samsung
and its users alike.

The specific cause of the second round of fires experienced by the
replacement Amperex-manufactured units was primarily a burr in the welding of the
positive and negative contacts to the battery cell. These tiny metal plates were
welded to the outside of the cell and served as the contact point between the
phone’s electronics and the battery pack. While the welding process generally
worked as intended, a small number of units included what Samsung has called a
"high welding burr" on the positive electrode. The heated metal used
to connect the positive electrode to the cell cooled with a sharp point on one side
rather than the smooth surface it was intended to have. This produced a
weakness in the battery when the welding burr punctured the insulation
tape designed to keep the battery’s layers separate in order to prevent a short circuit.
The point of the burr would essentially push through the tape making direct
contact with the negative electrode and resulting in a short circuit
followed by a runaway thermal buildup.9

Figure 5. Samsung’s Explanation of the "Battery B"

Figure 5. Samsung's Explanation of the "Battery B" Flaw

Source: Samsung

While the exact causes were different, the ultimate
result of the flaw in the Samsung SDI version of the Note 7 battery was
essentially the same as the result of the flaw in the Amperex version. Like
the "jelly roll" fault in the Samsung SDI cell, the welding mistake in the Amperex cells was also further worsened by a secondary issue, a lack of
insulation tape in certain units. This secondary issue was a plain and simple manufacturing
mistake that could have been easily prevented.

What These Findings Mean for Lithium-Ion Batteries as a Whole

Samsung’s woes may have become the poster child for the danger of lithium-ion
batteries as a whole, but they are just one of many
hundreds or thousands of companies using this technology in their products.
Another emerging use for this type of power cell has been
electric vehicles. While this includes something as relatively simple as the
aforementioned hoverboards and other small scooters, it also extends to the most
advanced electric cars on the road today. The most well-known producer of these
is Elon Musk’s Tesla brand. This company has been at the forefront of electric
car technology and has led the way in both the in-car systems and the power
cells being used to drive modern electric cars and SUVs.

To power its fleet of cars, Tesla chose lithium-ion technology. Of course,
since they are powering an entire automobile, these cells are much larger and
more numerous than any found in mobile devices. That said, they still pose
the same level of danger if improperly handled. While Tesla has done everything
possible to ensure the safety of its drivers and passengers, there have still
been incidents of fires caused by the Tesla’s line’s li-ion power cells, as well
as examples of explosions occurring after a Tesla is involved in a crash.10
These incidents have been investigated by the National Highway Traffic Safety
Administration (NHTSA), although the agency has yet to fault Tesla for any of
the accidents in which fires occurred. While Tesla did end up increasing the strength of its
fire shields to curtail preventable instances of road damage causing fires, the
possibility of a fire caused by a crash remains. Thankfully, the number of Teslas involved in crashes severe enough to trigger such a combustion has been
relatively small. Furthermore, it is important to remember that traditional
gasoline vehicles also contain a significant amount of combustible material of
their own in the form of gas and oil. Cars, like electronic devices,
require energetic fuel to power them. This fuel, when mishandled or damaged, can
result in fires or explosions. It does not matter if it comes in the form of a
lithium-ion battery or a tank full of liquid gasoline; energy-providing
materials tend to have energetic reactions when exposed to the type of impact or
heat a car crash can produce.

With this in mind, as well as the extreme rarity of lithium-ion battery fires
in even the one of the worst cases ever seen (the Galaxy Note 7), it is hard to
discount the technology’s value and potential despite ongoing fears
its safety. Simply put, lithium-ion batteries are far safer than many other
technologies that we use in our daily lives. Stoves or hot water heaters have
been known to explode if damaged or installed incorrectly, but these occurrences
are rare and will not stop anyone from cooking their food or heating their bath
water. Similar examples can be provided in many, many areas that humans are
exposed to in their daily lives, but in all cases the convenience and relatively
safety of the technology or machine in question outweighs the risks involved.
This is also true of lithium-ion batteries. Their power density is far superior
to any current alternatives and capable of providing users with small, lightweight
electronics that can still last for days on a single charge. Lithium-ion batteries, despite their flaws, are here to stay.

Still, the makers of these batteries and the devices they are installed into
must remain vigilant to ensure that they are providing the best possible product
with minimal safety concerns. Shoddy manufacturing can lead to situations like
the poorly made hoverboards that too frequently ignited. This must be avoided at
all costs by electronics maker and regulators, as well as by the consumer, who
can practice some simple safety procedures to further decrease any chance of an
accident. The next section will examine how both of these parties can work to
reduce even the modest danger than lithium-ion batteries currently pose.

Enhancing Battery Safety

This section will be divided into two parts: how the
electronics manufacturing industry can make batteries safer and how the average
consumer can take some easy steps of their own to ensure they are doing
everything they can to stop themselves from becoming the unlikely victim of one
of the very infrequent instances of battery failure that may still slip through
the cracks.

How Manufacturers Can Make Lithium-Ion Batteries Safer

The fact of the matter is that, no matter what manufacturers do,  there
will almost always be at least some very small, very rare instances of
lithium-ion battery fires. Even if device makers perfect their design and
production processes to the point where zero flaws make it through the
construction process, devices will still be susceptible to damage that can cause
them to ignite. This means it should be the goal of the battery and device makers of
the world to eliminate any chance of design flaws while minimizing the
of damage resulting in a fire. As a goal, this is entirely reachable. For
example, Samsung, through a truly massive investigation, did eventually determine the
exact cause of one of the most mysterious series of battery fires in history.
From a technical standpoint, this means all that needs to be done is to find all
possible areas where a short or thermal runaway can occur within a battery’s
design and eliminate them. Of course, this makes about as much practical sense
as saying "all you need to do to find a needle in a haystack is to eliminate all
the hay." In other words, the practical application of this task is
much, much harder than it seems on paper. Samsung, of course, would obviously
not have sent out its Note 7 devices with flawed batteries had it had even the
slightest inkling of what would occur. This blunder cost the company tens, if
not hundreds of millions of dollars, and it could have been avoided by simply
changing a few minor design elements.

Because of its monumental regret over the Note 7 fiasco, Samsung has become
something of an unintentional leader now in the process of making lithium-ion
batteries safer than ever. To this end, the company unveiled a series of new
design, manufacturing, and inspection guidelines that it will use moving
forward. The primary change is the implementation of a new 8-Point Battery
Safety Check that the company plans to use for all new devices and power cells
moving forward.11

Figure 6. 8-Point Battery Safety Check

Figure 6. 8-Point Battery Safety Check

While Samsung’s infographic is fairly comprehensive on the new
safety measures, more information can be gleaned by analyzing its provided data
and synthesizing it with the additional information provided by the company’s
investigation and other sources on battery safety. The following is a
point-by-point examination of the 8-Point Battery Safety Check and its likely
impact on the industry.

  • Durability Test – This promises to up the
    level of torture testing each power cell is put through to ensure that all
    new designs are capable of handling even extreme impacts and puncture
    events. Perhaps the most severe of these new test is the so-called "nail
    puncture" test. This exact test was originally performed on older models of
    lithium-ion batteries with much lower power density. However, it was no
    longer required as of the implementation of the current Underwriter’s Laboratory (UL) UL1642 testing standard that
    is widely used for modern li-ion battery packs. As one source puts it,
    "Whereas a nail penetration test could be tolerated on the older 18650 cell
    [a common model of battery no longer seen much in modern devices due to
    lower power density] with a capacity of 1.35Ah, today’s high-density 2.4Ah
    cell would become a bomb when performing the same test. UL 1642 does not
    require nail penetration."12  This means that Samsung is
    purposely creating at least one test in this portion of the Safety check
    that it knows most modern batteries would fail. It is an example of the
    materially higher standards its new cells will likely be held to.

  • Visual Inspection – This one is fairly
    self-explanatory. However, the company had already noted that it will
    provide additional training for inspection and assembly staff, and will
    improve the minimum standards these inspections look for.

  • X-Ray – This exact test could well have
    saved Samsung from the Note 7 battery fiasco. It would have been able to
    detect the misplaced negative electrode in the Battery A models, as well as
    the missing or punctured insulation tape in the Battery B models.

  • Charge and Discharge Test – While it is
    unlikely that Samsung will apply this test to each and every battery it
    produces, due largely to the stress it would put on new units before ever
    being sold, it does intend to apply it to batch extractions from all new
    models. This should catch any flaws that arise when the batteries being
    tested undergo their normal thermal expansion and contraction
    during the charge and discharge process.

  • TVOC (Total Volatile Organic Compound) Test
    – This aspect of the Safety Check will ensure that the electrolyte
    used within the batteries will be unable to leak from its intended
    container. Such a leak could easily result in a short, overheating, and
    thermal runaway.

  • Disassembling Test – This is another test
    targeted at catching the precise flaws that triggered the Note 7 fires. As
    the text above says, it will consist of disassembling sample batteries from
    new models to analyze "battery tab welding and insulation tape conditions."
    In other words, to check for the exact causes of the Battery B failures.

  • Accelerated Usage Test – This will focus
    on the ability of devices to hold up over the long-term. It will include all
    of the abuse, charging and discharging, and usage a device is likely to see
    over its entire lifespan. The idea here is to catch any flaws that may only
    arise once a device has already been out in the wild for months or years.

  • Delta Open Circruit Voltage (OCV) Test
    This will consist of tests conducted at regular intervals during the
    manufacturing process itself. These check-ins will look for voltage changes
    within a given battery during its passage through the assembly line. If an
    unintended change is detected, this could mean that a short circuit has been
    created in the unit, laying the groundwork for failure of thermal runaway
    events once it has been installed in a device.

While these tests will form the backbone of the new design
philosophy at Samsung SDI, the division of Samsung responsible for designing
mobile devices around these hopefully safer batteries has also committed to
taking its own actions to ensure improved safety. Among its plans are additional
space and supports being added to the areas surrounding a battery within a
device to prevent failures due to crushing or bending. This is just one example of numerous similar measures the
company has planned. These hardware tweaks will also be joined by a new initiative in
Samsung’s software design philosophy, with a focus on "improved
algorithms for governing battery charging temperature, charging current, and
charging duration."13

So, the question then is how can these ideals be applied by the rest of the
battery and device manufacturing industry. The answer is, fairly easily. The
first two tests in particular could combine to eliminate nearly all of the
known flaws that have been confirmed in lithium-ion construction to this
point. Reinstating the nail penetration test alone would result in undoubtedly
higher standards for batteries that have the real potential to see similar
damage out in the wild. Meanwhile, the x-ray test could find the exact types of
flaws seen in Samsung’s own disastrous Note 7 batteries. Although it would
almost certainly have rather have avoided the Note 7 fiasco, Samsung has
leveraged this negative to develop a series of guidelines that will hopefully
serve as a banner example for other power cell and device makers going forward.

This is not to say that all battery and device makers should simply sit on
their laurels and take Samsung’s new Battery Safety Check as gospel. Rather, it
is an excellent jumping off point from which battery safety protocols would
ideally be developed even further. Additional measures that should be explored

  •  The further strengthening of both smartphones and the outer
    "pouches" in which the battery’s cells are contained.
  • Continue the exploration of bendable battery cells like the flexible
    lithium-ion cells currently being developed by Panasonic.14 Not
    only would these be more resilient to failure from bending damage, but they
    would be extremely well suited to the long-rumored rise of flexible
  • The development of multiple, shielded cells. While this might slightly go against
    the trend towards always producing thinner and smaller devices, the
    inclusion of multiple smaller cells within the battery packs being included
    in mobile devices could lessen the potential severity of fires due to
    manufacturing flaws and damage alike. A thermal runaway event would be
    contained within a single, smaller cell with only a fraction of the fuel available to
    single-cell events seen in recent device fires.
  • The inclusion of a heat pipe. This is a move directed at the design of
    smartphones, and one already being implemented by LG.15 It consists of
    attaching a heat pipe to the device’s processing unit, rather than the
    battery itself. This saps the heat produced by the CPU, routing it away from
    the power cell and preventing any thermal reaction between the two
    components. While this specific interaction has not been verified as a cause
    for any known device fires, any introduction of external heat to a
    lithium-ion cell does raise its potential for failure, even if it is only by
    a miniscule amount.
  • Explore other battery technologies. Although Lithium-Ion batteries are
    currently the king of power density for small, lightweight mobile devices,
    the same could once have been said about technologies such as nickel-cadmium
    or lead-acid batteries. Battery technologies are always developing, and
    should continue to seek a safer, potentially even more efficient alternative
    to lithium-ion power. This is a valid goal from both a safety standpoint, as
    well as from a technological one as some believe that lithium-ion cells have
    reached their maximum potential energy density.16 If true, this
    would mean that as devices continue to get more power hungry in the future,
    the only way to meet their needs would be to include larger or multiple li-ion
    cells within their design. As making devices both larger and heavier to
    support these expanded batteries would run counter to the design philosophy
    of the entire electronics industry, it may be that lithium-ions days as the
    king of battery technology were coming to an end, even without the safety

Best Practices for Battery Safety for the End User

Although it is, of course, the duty of all device and battery manufacturers
to protect the public to the best of their ability, the end user can also take
some very simple steps to prevent any flaws that a manufacturer may have missed
from impacting them personally. Below is a list of these easy-to-implement
safety measures, along with how they could help prevent the user from being a
victim or the rare, but very real possibility of a lithium-ion battery fire.

  • Avoid Batteries from Disreputable Sources – This is the
    first, and possibly easiest way to avoid any kind of battery-related fire.
    Unfortunately, many companies located in countries with little or no safety
    regulation regarding the production of batteries are all too happy to
    provide their shoddy merchandise for inclusion in products that eventually
    make their way into the US. While there are regulatory and legal safeguards
    in place to prevent exactly this type of occurrence, they are far from
    foolproof, and have been circumvented by less that scrupulous parties
    multiple times. The most recent, and most flagrant of these was the 2015
    hoverboard fires. The batteries in these devices were produced by
    "thousands of interchangeable factories in China," and included almost none
    of the safety features required by more reputable manufacturers like
    Samsung.17 Given the fact that even Samsung can have a disastrous
    design make it into the public's hands, the complete lack of safety oversight should
    deeply frighten anyone that finds themselves in possession of one of these
    poorly made power cells. Unfortunately, even the maximum due diligence in
    researching an electronics purchase may not guard against all instances of
    these knock-off batteries. However, simple steps such as limiting
    electronics purchases to well-known brands, checking online reviews, and
    making purchases only at reputable retailers can help to minimize any chance of
    receiving a device that is a disaster waiting to happen.
  • Use Only Approved Chargers and Accessories – This is a
    step closely related to the first one. Even a well-made, perfectly designed
    battery cell could fail if it is charged by a charging device that does not
    correctly meet its designated electrical standards. This happens most often
    when a user purchases an "off brand" or "no-name" charger at a steep
    discount. Although these charger may physically fit the device in question,
    they are not necessarily going to provide the correct voltage to the device,
    and they may not cut off their charging input correctly, even when the
    device is fully charged. Either flaw in the design could lead to damage
    being done to the battery cell, resulting in its eventual failure. This can mostly be avoided by only purchasing chargers
    and charging cables from reputable sources. However, the safest practice, as
    a whole, is to use only the charger and cable that came with the device in
    question. The end user can be sure that these have been designed precisely
    to work with their device, and that any safety concerns introduced by them
    are minimal or non-existent. That said, even first-party accessories are not
    wholly safe from flaws. A recent spate of overcharging and overheating
    incidents has led to questions about the safety of the USB-C standard and
    its implementation, including incidents of both shoddy and first-party cables
    causing faults that resulted in
    ruined laptops and smartphones.18
  • Avoid Exposing Your Device to Extreme Temperatures
    This is a relatively easy measure to implement. However, it does require
    some forethought on the part of the user that may not realize just how easy
    it is for a smartphone or other mobile device to find itself in a situation
    that results in temperature gradients beyond its safe operating capacity.
    Common instances that could detrimentally affect a smartphone include in
    being left in direct sunlight for extended periods on a hot day; being left
    in an enclosed car under the same circumstances; being left in an outer
    pocket during extreme and extended cold; and even being left in the laundry as
    it passes through the washer or dryer. Although this last example is more
    likely to destroy the phone via moisture, newer water-resistant devices
    might survive submersion only to fail due to the extreme heat levels that
    can be present in a dryer. A good rule of thumb is to never expose your
    device to any temperatures that you yourself would not feel comfortable
    experiencing for extended periods of time.
  • Consider Carefully Before Using a Damaged Device – This
    measure is directed at all end users that continue using smartphones with
    significant damage that are, at least mostly, still functional. While a
    dropped smartphone with a cracked screen may still function initially, the
    damage that may have been done to the device internally could be much worse
    than its external appearance would suggest. Not all failures are immediate,
    and not all damage occurs on the outside. For example, a device that
    is sensitive enough for a miniscule soldering burr to cause a failure, as
    seen in the Note 7, could very easily fail when dropped onto concrete from
    even a moderate height. This is not to say that users should discard their
    smartphones after their first drop. However, any significant impact may
    warrant a checkup with a reputable repair person to ensure that not damage
    has been sustained by the device’s power cell that could ultimately result
    in a failure.
  • Use Common Sense – This last point may be obvious to
    some, but it is still worth going over. As devices become more and more
    rugged, things like water and dust-proofing may become the norm. This could
    lead to an overblown sense of safety when using devices equipped with
    lithium-ion batteries. That sense may be misplaced. Although devices
    are, undoubtedly, safer today than they have ever been before, user error
    can still very easily cause a failure resulting in combustion. A healthy
    level of caution when approaching the use and care of a mobile device can
    prevent many of these impact or submersion incidents from causing a battery
    fire. That said, no one should be stressed over the oft-promoted idea that
    some media outlets like to espouse of every lithium-ion device being nothing
    more than a bomb in your pocket waiting to explode. The odds of being the
    victim of one of these failures is already lower than sources of injury such as slip and fall accidents, car crashes, and other
    potential disasters that most humans have simply accepted as a possible, but
    danger of every day life. These slim odds can be further increased by
    implementing even a few of the suggestions made here to minimize the
    already microscopic risks of using a lithium-ion device even further.


[return to top of this report]

As a race, humans have generally come to depend on the ubiquitous presence of
their mobile devices as a part of their daily lives. Some have become dependent
to the point of addiction, or to feeling naked without a smartphone in their
pocket. Whatever a given user’s level of dependency on their mobile device, they
expect it to operate safely and reliably every time it is taken out of their
pocket or purse, and to never present a danger to their person or property. It
should be made very clear that this is exactly how essentially all mobile
devices operate the vast, vast majority of the time. However, this report was
written specifically to highlight those moments when that expectation of safety
has broken down, when a mobile device becomes the danger that users never want
it to be. It was not meant to suggest that everyone will experience such a
situation personally. In fact, it is entirely possible that no one reading this
report will ever fall victim to a lithium-ion battery fire simply due to the
extreme rarity of such occurrences. Yes, blunders like the Samsung Galaxy Note 7
fires have happened, and they could happen again. However, we are safer now than
we’ve ever been, partly due to incidents like those that have spurred additional
safety measures and improved device designs.

Hopefully, this report has served as both a primer on what can go wrong with
battery technology, as well as a guidebook for how to minimize those rare but
very real dangers. Humans are very, very unlikely to give up their mobile
devices any time soon, and will continue to need power for those smartphones,
cameras, laptops, and even automobiles. For now, the best source of this power
is lithium-ion batteries. This may change within a few years, but, in the
meantime, we can only remain vigilant in our own practices, and observant in
manufacturing practices to ensure that the lowest possible risk in continuing to
use these power cells has been achieved.


1 Weise, Elizabeth. "Why Lithium-Ion Batteries Go Up in
Flames." USA Today. September 2016.

2 Ibid. 

3 "BU-304a: Safety Concerns with Li-ion." Battery University.
Retrieved January 2017

4 Ibid.

5 Krebs, Robert E.
The History and Use of Our Earth’s Chemical
Elements: A Reference Guide

. Greenwood Publishing Group via Google Books.
Retrieved January 2017

6 "[Infographic] Galaxy Note7: What We Discovered." Samsung. January

7 Ibid.

8 Ibid.

9 Ibid.

10 Meier, Fred. "Tesla Beefs up Fire Shields, NHTSA Ends Fire Probe."

USA Today

. March 2014.

11 "Samsung Announces New and Enhanced Quality Assurance Measures to Improve Product Safety." Samsung. January 2016. 

12 Ibid.

13 Ibid. 

14 Coxworth, Ben. "Panasonic’s New Flexible Lithium-Ion Battery Can Do
The Twist"
New Atlas

. October 2016

15 Jonnalagadda, Harish. "LG Undergoing Extensive Battery Tests, Uses Heat
Pipe to Prevent Overheating"
Android Central

January 2017.

16 Ibid.

17 Hollister, Sean. "Here are the Reasons Why So Many Hoverboards Are
Catching Fire." CNet. July 2016.

18 Bohn, Dieter. "A Software Fix for Dangerous USC-C Cables is Coming"

The Verge

. April 2016.

About the Author

[return to top of this report]

Michael Gariffo is an editor for Faulkner Information Services. He
tracks and writes about enterprise software, the Web, and the IT services
sector, as well as telecommunications and data networking.

[return to top of this report]