When batteries are used improperly or under poor quality, they sometimes catch fire or explode. Scientists and startups have long been committed to building safer batteries. They are committed to developing and testing new materials, hoping to solve problems once and for all. But it seems that each Methods have problems that are difficult to solve, and now the most practical solution may be the most conservative solution.
There are three main steps to improve the safety of the battery: the battery electrolyte avoids the use of flammable liquids; the battery components must be fireproof; improve the existing safety functions in the battery. These are slow changes for the battery.
It is important for technical researchers to understand the basics of battery operation and the causes of battery failure. Obviously, most people talk about lithium-ion batteries, which is the most common type of battery, because lithium batteries can provide so much energy. Scientists also Magnesium batteries (which discharge very slowly) and sulfur batteries are being developed (will not last long), but lithium-ion batteries are still the mainstream in the market.
Lithium-ion batteries are mainly composed of two electrodes or conductors. The lithium ions in the electrolyte move from one side to the other. The electrolyte in the battery is a highly flammable chemical.
There are several different reasons for a battery explosion or fire. The most common is that too much heat or poor battery design can cause the electrolyte to react in a way that generates heat. This 'thermal runaway' phenomenon causes the battery to catch fire or explode. Battery manufacturers usually place spacers between the two poles of the battery to prevent them from coming into contact. If the diaphragm fails, it will catch fire or explode, which is what happens with Samsung mobile phone batteries.
So how to solve this problem?
Today, a promotional solution is to develop solid-state lithium-ion batteries. The idea is simple: instead of using flammable liquid electrolytes, electrolytes are made from solid materials; solid-state lithium-ion batteries are less likely to explode or catch fire. Solids are more difficult than liquids, which means that solid-state batteries are difficult to design, expensive, and may have performance issues.
There are three main materials for producing solid-state lithium batteries. Michael Zimmerman, a material scientist at Tufts University in the United States, and founder of solid-state lithium-ion battery company Ion Materials, explains that ceramics, glass or polymers can be used to produce electrolytes.
Ceramics and glass have fragile properties and can easily break down once pressure is applied. Zimmerman says that ceramics and glass are also difficult to mass produce because people need a lot of batteries, which makes it impractical to use these materials in large quantities. Also, in production The process of these materials sometimes releases toxic gases.
Another material is polymers. Some polymers can conduct ions, but usually only work at extremely high temperatures. Zimmerman's team has developed a polymer that conducts ions at room temperature but is also flame retardant. In a video, they demonstrate how to cut them into pieces without catching fire.
Now, Ionic Materials is working with battery manufacturers who need to change the way they make batteries to fit new polymers. Zimmerman says he hopes to launch the battery in the next two or three years.
Two or three years does not sound long, but there are some people who can't wait for the industry. 'Some manufacturers promise that solid-state lithium-ion batteries will enter the market in the next two to three years. In recent years, investors have been on solid-state lithium battery technology. Progress is getting more and more impatient. 'Ian McClenny, an analyst at Navigant Research, a research institute specializing in battery research, said.
McClenny said that some electric vehicle manufacturers have said they have made breakthroughs in solid-state lithium-ion battery technology.
But McClenny believes that almost all solid-state lithium-ion batteries are not commercially produced.
The main driver driving battery innovation is electric vehicles, and now, most solid-state lithium-ion batteries work for a year and a half. This may be acceptable for mobile phones, but for expensive electric vehicles, this is almost It is not feasible.
Surya Moganty, chief technology officer at NOHM Technologies, said another strategy for finding a safer battery is to make the electrolyte itself fire-resistant, even though it's still liquid. They use 'ion solids' to develop electrolytes that are similar to salt, but It is a liquid at room temperature.
Making this material into an electrolyte makes them flame retardant, but there may also be battery life problems. NOHM is improving the formulation so that batteries using its technology can last up to 500 charge and discharge cycles and also work with manufacturers. A license to get the technology. A similar problem plagued researchers, who developed a water-based battery last year that is safe. The cell voltage can reach 4 volts, the same voltage as the organic electrolyte, but the charge The discharge cycle is only about 70. As Moganty pointed out, battery manufacturers hope that this battery will last for at least 500 charge and discharge cycles.
Moganty said that among these exciting technologies, there seems to be no mature technology.
Now, the most effective strategy may not come from major technological changes or reinventing new batteries. It is a battery that improves on existing features. For example, a battery that already contains a battery management system, which is a system that monitors battery operation. Software, can detect if there is a problem with the battery.
McClenny said, 'The ability to pinpoint non-compliant batteries can extend battery life.'
This is similar to the approach taken by San Diego-based battery safety company Amionx, a company that was separated from the battery company American Lithium Energy, whose research used to produce fire-resistant batteries for the US military.
Bill Davidson, the company's chief operating officer, said that their technology name is SafeCore, the last line of defense for battery safety. SafeCore technology does not change the components of the battery itself, it only uses a layer of insulation inside the battery, which can be blocked before the fire Break. When triggered by an overheated or too high voltage, this layer of isolation material will break the connection between the battery electrodes and regulate the current through the battery.
Although the battery explosion has attracted much attention, just like Samsung's Galaxy Note 7 phone, but from a statistical point of view, today's battery is safer than in the past.
In terms of security, the simplest solution is not necessarily technology, but structure. Technical experts say that, in theory, lithium-ion batteries have reached 90% of their maximum battery life, and many manufacturers are committed to faster development. , a more powerful battery.
McClenny said that if companies adopt incremental improvements rather than quickly finding a solution to increase capacity and power density, then the batteries they produce may be more sustainable.
