Why can't aluminum air batteries replace lithium batteries?

The chemical reaction of aluminum air battery is similar to that of zinc air battery. Aluminum air battery is made of high purity aluminum Al (containing 99.99% aluminum) as negative electrode, oxygen as positive electrode, and potassium hydroxide (KOH) or sodium hydroxide (NaOH) aqueous solution as electrolyte. . Aluminum takes up oxygen in the air, produces a chemical reaction when the battery is discharged, and converts aluminum and oxygen into aluminum oxide.

Aluminum air battery will replace lithium battery ?

Currently available as an alternative lithium cell, aluminum is still in the trial stage, there is no commercial use. So in general, whether aluminum air battery will replace lithium battery is still unknown, then let's see what problems will be encountered when replacing aluminum battery with lithium battery.

From the battery's cruising range, aluminum air batteries are indeed a breakthrough compared to lithium batteries. However, since the aluminum air battery generates hydrogen during the discharge process, it will not only cause loss of the anode material, but also increase the internal loss of the battery. In addition, the aluminum air battery consumes aluminum, which is needed when the battery life is over. The re-installation of aluminum and the like has greatly hindered the commercial development of aluminum air batteries. And in terms of automotive applications, aluminum air batteries are still unknown, not even comparable to hydrogen fuel cells.

Analysis of the reasons why aluminum air battery cannot replace lithium battery

1, mostly used for emergency power

“Aluminum air battery is not a battery used to store electrical energy for many times in the traditional sense, but a chemical reaction device that releases electric energy.” Chen Tao said that its working principle is the process of oxidation of active metal in water to release energy. - The released energy is output as electrical energy through an electrolyte and a special electrode material.

Generally speaking, for aluminum air batteries, the active metal is aluminum, similar to zinc air batteries, magnesium air batteries, etc., but only according to the activity of the metal (the severity of the oxidation reaction in water or air) The electrolyte used and other auxiliary materials are slightly different.

"'Only just add water" is only in the life cycle of the battery. The substance consumed in essence is aluminum, not water." Chen Tao told reporters that in the battery work process, the power is continuously output, metal aluminum It is also continually oxidized and consumed to produce aluminum hydroxide, which is produced on the condition that it consumes aluminum containing chemical energy. “The 100 kilograms of aluminum air battery stores enough electricity to drive 3,000 kilometers.” After 3,000 kilometers, the battery life is over and needs to be reinstalled, that is, metal aluminum.

According to reports, aluminum air batteries have been around since the 1960s. But until now, most of its research has remained at the theoretical stage, and there are not many practical applications. At home, its research focuses on emergency power supplies; while abroad, scientists or researching certain electrode materials, or researching battery systems for special applications, are trying to find breakthroughs in aluminum air battery applications.

2. Safety risks are to be tested

“Inconvenient use is the biggest bottleneck of aluminum air batteries at present.” Chen Tao believes that in addition to the inconvenience of using batteries that store more electrical energy, there are also many inconveniences compared with other fuel-based fuel cells. For example, hydrogen fuel cells can easily add hydrogen. Noted, stored, and transported to chemical reaction devices, but it is obviously inconvenient for aluminum in solid metal. Secondly, there are many side reactions and the reaction process is not easy to control. Some of the reaction products hinder the reaction from proceeding to a certain extent, releasing a large amount of heat and simultaneously generating flammable and explosive gases.

On the road to research and development of electric vehicles, aluminum seems to be playing a more important role. An interesting phenomenon is that the battery life of the US Tesla electric car can be increased to 300 km to 400 km. The battery used is mainly nickel-cobalt-aluminum ternary material, while the electric car in China uses nickel-cobalt-manganese. The difference between the metals is aluminum.

“The aluminum material used in Tesla is mainly applied to batteries that can store electric energy multiple times. Its function is to increase the energy density of the battery, and the battery of the same weight can store more electric energy, so that the driving range of the car is more. Long." Chen Tao believes that from this point of view, it is indeed a breakthrough. However, the resulting security risks are subject to further testing.

Electric vehicles driven by lithium-ion batteries are difficult to popularize. The biggest obstacle is limited mileage. The current endurance is mostly between 135 km and 480 km. Unless there are a large number of fast charging stations along the way, it is not appropriate to drive electric vehicles for long distance travel. A few vehicles larger than 200 kilometers are particularly expensive and cannot be popularized.

3, the car is still unknown

Can an aluminum air battery replace a lithium ion battery? Geely Automobile Research Institute has done related simulation modeling experiments. From the perspective of vehicle dynamics, it studies the application of aluminum air battery as the vehicle energy source for electric vehicles, focusing on the amount of power and power that can be released by itself.

“From the experimental results, the aluminum air battery is more suitable as a battery backup battery.” Du Zhiqiang said that the aluminum air battery is an energy source, and the energy of the same weight aluminum air battery can be released compared to the storage battery. More, its energy density is high, but its releasable power is extremely low, and its use alone does not meet the needs of the car, especially when it is just starting. This is equivalent to a fuel car, the fuel tank is large, but the engine is very small, can go a long way, but it is very slow. In contrast, the speed of lithium-ion batteries will be more stable. If an aluminum air battery with the same power (that is, the vehicle has the same speed), the weight will be 4 to 5 times that of the lithium ion battery.

In other words, the standard energy of an electric car should be that the actual length of the aluminum air battery is used to obtain a longer driving range, and the aluminum air battery is short, with a power type battery. The vehicle has good dynamic performance.

“For automotive applications, aluminum air batteries are still unknown.” Du Zhiqiang believes that aluminum air batteries are currently used in mobile communication devices and notebook computers, but they are experimental and not very extensive. In the future, in the field of electric vehicles, there are still many technical problems to be solved urgently. Whether it can successfully become an electric vehicle vehicle energy depends on the final choice of the market. In other fields, from the technical characteristics of the aluminum air battery itself, it seems more suitable as an emergency power source and a mobile power station.

From the current selection of Geely's electric vehicle battery, it is basically in line with the industry. The production model is mainly based on lithium iron phosphate. The models being developed are basically using ternary materials. Du Zhiqiang said, "I personally believe that the future development direction is based on the existing battery, increase the fuel cell, form a hybrid fuel supply of 'fuel cell + battery', in the fuel cell selection, hydrogen fuel cell is better than aluminum air battery Wait for metal fuel cells."