Don't blame the battery for every lithium battery explosion
Lithium battery explosion often appear in the news for terrible reasons, but the problem is far more than the battery itself.
Lithium-ion batteries have been making headlines due to various errors. The latest moment involves a pair of explosive headphones on an airplane. Following the Samsung Galaxy Note 7 (dual) recall and major problems with the “hoverboard” battery, this burning incident has become a hot topic. You can’t blame all this on incompetence. Even rocket scientists have difficulty controlling lithium-ion batteries.
Essentially, lithium-ion batteries are dangerous. Internally, the main line of defense against short circuits is a thin and porous layer of polypropylene that prevents electrode contact. If the separator is broken, the electrodes will come into contact and will soon become very hot. The battery is also filled with a flammable electrolyte, which will burn when heated, and will really start burning once oxygen enters it. Not scary enough? This liquid is mixed with a compound that can burn the skin.
So why use them? Lithium-ion batteries are very efficient. They pack a lot of energy in a small package that can keep a mobile phone or laptop running all day. Lithium-ion power battery is also a very mature technology. More than 25 years ago, the first batches of rechargeable lithium-ion batteries were used in Sony’s Handycams, and now there are dozens of battery suppliers around the world. If you are building a camera, car, airplane, or fitness tracker, adding a lithium-ion battery to the manufacturing process is usually a plug-and-play step.
But unlike most mature technologies, they seem to become more unstable over time. That’s because we need to provide higher capacity batteries in a thinner package at a cheaper price. The symptoms may be the same-they will explode-but many factors cause lithium ions to appear in the spotlight for unnecessary time.
Reasons behind lithium battery explosion
Reason of lithium battery explosion: Production defects
For all these exploding batteries, the effortless diagnosis is that there must be a problem with the way the battery is manufactured. This is often the case, but as Samsung’s Note 7 legend shows, identifying specific problems is not so simple. The initial recall involved mobile phones that used Samsung’s own batteries. There was not enough space between the battery protection bag and the internal electrodes of these mobile phones. This compression bends the electrodes in some batteries, causing them to contact and short-circuit.
However, once these phones are recalled, replacement devices with “safer” batteries provided by another company will have different problems. Many of the insulation is not good, and some of the internal jagged edges damage the most important separator. This also caused a short circuit, but the reason was completely different.
Reason of lithium battery explosion: Design flaws
Most modern gadgets are designed to be as thin and stylish as possible. This may cause serious damage to the battery made by the original manufacturer, especially when a large-capacity battery is installed in a small body. Pressure from the hardware surrounding the battery can damage the electrodes or separator and cause a short circuit. Insufficient ventilation or thermal management can cause the flammable electrolyte in the battery to heat up. Once the temperature is too high, chemical reactions will cause the temperature to rise further and get out of control. This is a condition called thermal runaway, and it usually ends with an explosion or fire-once the oxygen comes into contact with the chaos, the situation gets worse. Design flaws is often ignored as a important reason of lithium battery explosion.
Reason of lithium battery explosion: User-supplied damage
Even if a small tool is well designed, dropping it and wearing it for a long time can damage its unstable power supply. The best way to tell if your battery is damaged is if it appears to have all swelled—proving that the chemicals in the battery are generating gas in a way that shouldn’t be. This expansion also creates its own pressure on the battery case, which may cause puncture or fire. Unfortunately, most mobile phones nowadays have sealed batteries, and disassembling the device for inspection will break the warranty. If your phone case seems to be pushed open or feels unusually hot to the touch, it is best to be careful and take it for inspection.
Reason of lithium battery explosion: Charger problem
If you leave your own charging cable at home, consider buying a cheap off-brand charging cable. Some of these cables and wall warts are so cheap for a reason: In order to achieve such low prices, the companies that make them often skimp on insulation, evasion of safety laws, and power management functions. It may cause your phone to get an electric shock, the charger to explode, or fire.
Reason of lithium battery explosion: Industry pressure and competition
If a company can save a few cents on each battery, that can translate into millions or billions of profits. As a result, many lithium-ion battery manufacturers cut corners to price their batteries cheaper. There may be defects in the material, causing damage to the already thin partition. Maybe they can save a few dollars by saving insulation or quality control. These things are likely to be the main reason for the fire of these hoverboards: the first models on the market are expensive, and their popularity has given birth to counterfeit products with lower prices and even cheaper internal parts. Crowdfunding and affordable components democratize the consumer electronics industry, but cost savings often come at the expense of security.
All in all, under normal circumstances, lithium battery explosion will not happen. LiFePO4 battery is safer in normal use, but it is not absolute, and may be dangerous in some extreme situations. Related to manufacturers, design defects, user-supplied damage, charger problems, industry pressure and competition.