Electric vehicle battery for safety, battery science operation guarantees high performance
China Rare Earth Industry Association and China Rare Earth Society held a standard review meeting in Baotou City Mingming Rare Earth New Power Technology Co., Ltd. (hereinafter referred to as Yanming Rare Earth) to review the "High Abundance Rare Earth Hydrogen Storage Alloy for Capacitive Ni-MH Power Battery" and "Package type nickel-hydrogen power battery for pure electric large city passenger car" 2 group standards.
The battery is called the "heart" of electric cars, and its importance is self-evident. It is understood that the nickel-hydrogen power battery produced by Yan Ming rare earth is based on the addition of new rare earth materials. "The development of standards has filled the standard gap in China's production specifications for capacitive Ni-MH power batteries and their high-abundance rare earth hydrogen storage alloys, providing a reference for the design, production, inspection and management of these products in the future." Qiao Mingang, assistant director and minister of Ming Rare Earth, said.
R&D power battery is due to energy pressure
In the 1970s, the oil crisis in the Middle East emerged, and the pressure on global energy conservation and emission reduction gradually increased. Countries began research on various types of new types of batteries. Among them, nickel-hydrogen batteries have attracted widespread attention due to their advantages of environmental protection and safety, and gradually entered commercial use. Power battery ranks.
In order to further improve the high current performance and low temperature performance, in 1997, Russia first developed the asymmetric supercapacitor-Ni(OH)2/C type supercapacitor representing the third generation capacitor, and the negative electrode is a high specific surface area carbon material, which can replace Ni-MH battery anode hydrogen storage alloy, used directly in extremely cold regions such as Siberia.
In the 21st century, Chinese scientific research workers have developed a new type of rare earth new power source for alpine and high altitude areas based on China's rare earth resource advantages and power battery industry foundation. This innovative capacitive Ni-MH power battery is based on the application of new rare earth materials. It adopts an asymmetric combination and integrates nickel-hydrogen power battery and supercapacitor advantage system through process and equipment innovation to meet commercial power battery. Safety, low temperature resistance, high current charge and discharge, long life, environmentally friendly and reasonable price.
Yuan Aidong, the deputy general manager of Yanming Rare Earth, is proud not only for the performance of the product, but also for its more “drilling”. Nickel-hydrogen batteries produced in Japan, Germany, the United States and other foreign countries are mainly used in hybrid vehicles, but Capacitive Ni-MH power batteries are used in pure electric buses, and only one rare earth is found in China and abroad.
Battery science operation guarantees high performance
The author saw in the Mingming rare earth production line that a batch of blue nickel-hydrogen power batteries were taken out of the workshop by the transport robot and went to the domestic market. "Our products are safe, cold resistant, fast charging, long life, environmentally friendly, recyclable and other six characteristics." Qiao Mingang introduced.
As we all know, the excellent characteristics of the battery depend on the internal structure of the battery and its operating principle. The capacitive nickel-hydrogen battery consists of a positive plate, a negative plate, a diaphragm, an electrolyte, and a casing.
The positive electrode plate is prepared by a wet process, using a three-dimensional nickel belt or a carbon ribbon as a current collector, Ni(OH) 2 as a main body of a divalent metal hydroxide, and the negative electrode plate is composed of a hydrogen storage alloy and a capacitor material such as carbon. The three-dimensional nickel belt, the two-dimensional steel belt or the carbon ribbon substrate is prepared by layering and coating; the diaphragm is composed of a polypropylene material in the form of a fiber membrane, and the ceramic material ZrO2 fiber is contained in the middle; the electrolyte is matched by a ternary alkaline material. Ratio; the housing is mainly made of high-strength, corrosion-resistant stainless steel or plastic material.
"Charging and discharging process is the reciprocating motion of hydrogen atoms or protons between the electrodes, does not produce any intermediate state of soluble metal ions, and does not consume or generate any electrolyte structure, which can achieve complete sealing and maintenance-free, which is the battery can achieve The key to the six functions." Yuan Aidong preached.
It is reported that during the charging process, H+ in the positive active material first diffuses to the OH-reaction of the positive/solution interface and the solution to form H2O. Then, the free H+ in the solution is electrochemically reacted by diffusion of the electrolyte to the interface of the anode/solution to form hydrogen atoms and further diffused into the hydrogen storage alloy of the anode material to form a metal hydride. The discharge process happens to be the reverse of the charging process, and capacitor materials such as carbon are always active participants in the reaction process.
"In fact, during the charging and discharging process, the surface of the alkaline electrolyte in the carbon-coated hydrogen storage alloy electrode electrochemically reacts to store and release atomic hydrogen, and the activated carbon on the surface of the hydrogen storage alloy electrode forms a conductive network, improving At the same time as the conductivity and electrocatalytic activity of the alloy electrode, an electric double layer is generated, and part of the charge is physically stored-released," said Yang Wenhao, secretary general of the China Rare Earth Industry Association.
Power battery should pay attention to standards
With the rapid development of the new energy automobile industry, the state has stricter requirements for battery manufacturers in terms of research and development, quality assurance, and production consistency. The Ministry of Industry and Information Technology has emphasized the issue of ensuring consistency in the production process.
The traditional battery production process is complicated and cumbersome, and the production process is mostly manual operation, so the consistency is low, which seriously affects the overall performance of the power battery.
As a vehicle-mounted power battery, the standardization of capacitive nickel-hydrogen battery cells and their modules is the industrial basis for mass production. The intelligent production workshop can realize information dataization, process visualization and decision-making intelligence. All the batteries that go out of the smart workshop will be incorporated into the company's self-created Yanming Rare Earth Big Data Monitoring Platform to realize data sharing. In addition, the smart workshop can complete the process design with one button, all equipment can carry out intelligent detection, monitor and record real-time data, and alarm the abnormal situation.
"According to the characteristics of capacitive Ni-MH power batteries, different charging methods are needed according to regional characteristics. This standard is also researched by our company." Yuan Aidong said.
For the alpine region, the technical route of direct charging operation of pure electric buses with “fast charging and quick filling” as the main mode was developed. The so-called "fast charge fast fill", that is, intermittently fast replenishment of electricity during the day, can be used to supplement the amount of electricity consumed by vehicles from 30 km to 50 km in about 10 minutes. This is an extremely simple charging mode that provides more than 300 kWh of effective power per day for pure electric buses.
For the areas with high air humidity, the technical route of direct charging operation of pure electric buses with "slow charging and quick filling" as the main method has been developed. The so-called "slow charge fast fill", that is, slow charging at night, supplemented by intermittent fast during the day, is also an extremely simple charging mode, which can be fully charged in the evening for about 1 hour, and during the daytime in the initial parking gap. In about 10 minutes, you can replenish the vehicle's electricity consumption from 30 km to 50 km.
Since February 2012, more than 100 12m capacitive Ni-MH power battery pure electric buses have been commercialized on the 6 bus lines in Zibo, Rizhao and Baotou, Inner Mongolia, and operate safely. This fully confirms that the capacitive Ni-MH power battery not only directly solves the pure electric bus in the “Three North Area” (Northeast, Northwest, North China) due to its high efficiency, stable quality, environmental protection, energy saving and long-lasting performance. The three outstanding problems of running cold, not running too fast, and battery decaying too fast, and leading the development direction of power battery technology in pure electric bus industry.