Note7 continuous explosion, Apple developed solid state battery

After recalling and replacing the new machine, it still could not stop the continuous explosion. Note7 undoubtedly caused Samsung's brand image to fall to the bottom, and Apple took the opportunity to "oil on the fire".

On October 14, Apple submitted a patent for "explosion-proof" mobile phone batteries. The patent shows that Apple is developing a technology that can extend battery life without exploding. The patent focuses on the battery case, and even if the inside of the battery explodes, a solid case made of special materials can ensure that the user is not threatened by security.

At the same time, this new housing technology allows the shape of the battery to be designed according to the internal structure, somewhat similar to the battery structure of the new Macbook. In addition, the gap between the battery stacks is reduced, and problems such as battery expansion are reduced.

As smart phone screens become larger and more functional, the requirements for battery life are getting higher and higher. How to balance battery performance and life has become a huge challenge. Behind this, the battery industry's fight against the infighting is also extremely fierce.

Fighting in the dark: Samsung Note7 continues to explode Apple to develop solid-state batteries

Diaphragm defects cause an explosion

At the moment, most smart phones use lithium-ion batteries.

From the working principle, there are generally two electrodes on both sides of the battery, a cathode containing a positive ion, and an anode containing a negative ion. When charging the phone, lithium ions move from the cathode to the anode; when we use the phone, that is, when the power is released, the lithium ions move from the anode to the cathode and move in the opposite direction. There is an electrolyte chemical between the two, which can effectively help the ion to move and conduct current.

However, it is worth noting that even if the ions continue to move, the yin and yang poles are absolutely inaccessible, so the battery manufacturers will also insert spacers between the yin and yang poles to ensure safety. Once there is a problem with the partition, there is a possibility of explosion.

In the GalaxyNote7 bombing, Samsung explained that the partition was defective and the yin and yang of the battery touched each other, causing an explosion.

In the eyes of the industry, this may be the result of battery manufacturers pushing technology to the limit. As the screens of smart phones become larger and more functions, the requirements for battery life are getting higher and higher. When there is no breakthrough in mobile phone life, manufacturers can only use battery life. And the charging speed is as extreme as possible.

For example, in order to increase the battery's volumetric energy density and extend the endurance, manufacturers will use thinner diaphragm materials between the two poles, but may be thinned due to poor quality control, poor materials, or other reasons. It is impossible to effectively isolate the positive and negative electrodes. At this time, it is easy to cause an accident in the battery.

This time, after the replacement of the "security version" Note7 still frequent explosions, so that Samsung finally cannot stand the pressure. On October 11, South Korea's Samsung Electronics announced that it will stop selling and replacing Note7 smart phones worldwide, and for safety reasons, it is recommended that all consumers stop using the phone.

According to the official website of the AQSIQ, after the law enforcement supervision department conducted the interview and initiated the defect investigation, Samsung filed a recall plan with the AQSIQ and decided to recall the sales in mainland China from October 11, 2016. All SM-N9300 Galaxy Note7 digital mobile phones, a total of 190,984 units (including 1858 products were first recalled on September 14, 2016).

Some analysts said that if Samsung completely stopped selling Note7 phones, it would lose up to about 19 million mobile phones, with a total value of about $17 billion. And including some other expenses brought by the replacement, the recall loss will be immeasurable.

Industry experts believe that the design of the battery separator should consider two aspects. The first is that the cell isolation film is not enough between the positive and negative poles. There is a special term called Overhang. This safety margin is first designed to prevent sufficient clearance of the positive and negative poles when the cell expands and contracts. Secondly, in order to ensure that in the cell dewatering process, the separator becomes too short due to heat shrinkage, so as to affect the insulation.

In addition, it is a foreign matter carried by the diaphragm itself. Because the finished diaphragm is bundled like a tape before entering the cell production line, it is easy to get some small particles, such as dust, particles falling from the employee's operation, and even particles of the battery's positive and negative materials. and many more. These particles are likely to puncture the barrier film. After all, the film is only 20 to 30 microns thick, especially for automotive power cells, often between 20 and 25 microns.

The battery market is full of three

Mobile phone batteries are divided into nickel batteries and lithium batteries. Among them, nickel battery has low capacity, memory effect, self-discharge phenomenon, and environmental pollution caused by manufacturing materials, so it has not continued in the mobile phone industry. The lithium battery makes up for the shortage of nickel battery, and its high energy and environmentally friendly characteristics make it the only source of power for the current mobile phone.

Lithium batteries are usually divided into two categories. A lithium metal battery is generally a battery using manganese dioxide as a positive electrode material, metallic lithium or an alloy metal thereof as a negative electrode material, and a nonaqueous electrolyte solution. A lithium ion battery is generally a battery using a lithium alloy metal oxide as a positive electrode material, graphite as a negative electrode material, and a nonaqueous electrolyte.

Although the lithium metal battery has a high energy density and can theoretically reach 3,860 watts/kg, it cannot be used as a power battery for repeated use because it is not stable enough and cannot be charged. Lithium-ion batteries have been developed as the main power battery due to their ability to be repeatedly charged. However, because of the combination of different elements, the composition of the positive electrode material in a variety of performance differences, resulting in the industry's disputes on the positive material route.

In general, power batteries mainly include lithium iron phosphate batteries, lithium manganate batteries, lithium cobalt oxide batteries, and ternary lithium batteries (ternary nickel cobalt manganese).

A related person from BYD told reporters: "lithium cobalt oxide battery is used more in mobile phones and notebooks. Lithium manganate batteries are used more in Japanese cars, such as Nissan. Lithium manganate batteries are safer than lithium cobalt oxide. The battery is better, because the lithium cobalt oxide battery has more energy to store in order to pursue energy density. Although it also knows that it has some safety problems, the probability of danger is very low. The whole industry and the whole world are still tolerant. It is impossible to return. In the era of 'big brother', the battery accounts for a large part of the volume. But the car is different. The safety of the car is very important, so it will do some discarding on the electric energy. The safety of the lithium manganate battery is better than that of the lithium cobalt oxide battery. However, the energy density is not as large as the latter. On the other hand, the lithium manganese oxide battery is more attenuated."

According to the research and analysis of the Prospective Industry Research Institute, it is expected that the scale of China's pure power lithium battery industry will exceed 160 billion Yuan in the next 10 years. The upstream lithium resources, key materials in the middle reaches and downstream battery assembly market will continue to benefit.

The world battery market can be described as “three-legged” in China, Japan and Korea. In 2015, the first place in the field of electric vehicle batteries was Japan’s Nissan and NEC joint venture AESC, accounting for 23.5% of the world market; followed by LG Chemical (16.6%), BYD, Panasonic Samsung SDI. In the field of small batteries on devices such as smart phones, Samsung SDI has a 25% market share, ranking first, with LG Chemical accounting for 16%, ranking second, followed by Panasonic, ATL (China) and Sony.

Samsung SDI is a subsidiary of the Samsung Group. Lithium battery is one of the main businesses. In 2014, it began to develop non-replaceable batteries for mobile phones, but lost to LG, ATL and other competitors in the Galaxy S6. In the GalaxyNote7 project, Samsung SDI finally supplied most of the battery, but did not expect to encounter such a thing.

It is reported that Samsung's next-generation flagship Galaxy S8 will give up SDI and use LG's battery. However, the deal remains to be seen before Samsung and LG sign the final agreement. Samsung and LG compete in almost all consumer electronics sectors, from smart phones to home appliances to television. Due to concerns about technology leaks, the two companies rarely use each other's parts.

Is solid state battery the best choice?

According to the latest news from foreign media, Apple seems to be more eager to learn from the GalaxyNote7 incident than Samsung, and has applied for a design patent on battery and user safety.

Apple wrote in the patent application description: "Battery performance of mobile electronic devices and other computing devices has become more and more popular, especially as mobile devices are getting smaller and smaller, but their demand for performance is increasing. This is especially true under the premise of higher levels. Therefore, maintaining equipment capacity while improving battery life has become one of the continuing challenges for equipment manufacturers."

The patent shows that Apple is developing a technology that can extend battery life without exploding. The patent focuses on the battery case, and even if the inside of the battery explodes, a solid case made of special materials can ensure that the user is not threatened by security.

At the same time, this new housing technology allows the shape of the battery to be designed according to the internal structure, somewhat similar to the battery structure of the new Macbook. In addition, the gap between the battery stacks is reduced, and problems such as battery expansion are reduced.

It is worth noting that since 2012, Apple has been actively deploying patents for all-solid-state battery technology, and expects to use this new battery in devices such as iPads and MacBooks and flexible electronic devices to be developed in the future. In November 2015, the US Patent and Trademark Office announced a new patent related to solid-state battery charging technology, the solid-state battery charging technology for portable devices.

The so-called all-solid-state battery is a type of battery in which there is no gas, no liquid, and all materials exist in a solid form. Lithium batteries have a chance of bulging, and lithium batteries have a limited operating temperature range, and life at high or low temperatures is easily affected, but all solid-state batteries do not have these problems.

In the industry's view, solid-state batteries may become the mainstream of the next battery development. However, in an all-solid-state lithium battery, the solid-solid contact between the electrode and the solid electrolyte has higher interfacial contact resistance than the solid-liquid contact, and the interface compatibility and stability also significantly affect the all-solid lithium battery cycle performance and rate performance. In addition, solid-state batteries are also facing bottlenecks in the development of production processes to be improved and costs to be reduced.

To this end, many research institutions have done a lot of research and development. For example, Sun Culture Solar in the United States applies solid-state battery technology to the field of energy storage. It has developed a new integrated solar panel with built-in solid-state low-voltage battery and seamless integration with the inverter. This fully integrated product design reduces total solar installation and energy storage costs by more than 50%. Researchers at the Federal Institute of Technology in Zurich, Switzerland, use garnet as an electrolyte to amplify the contact area between the solid-state battery electrode and the electrolyte, thereby achieving the effect of accelerating the charging speed of the solid-state battery and withstanding the high temperature of 100 °C.

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