When lithium-ion batteries are now cell phones, laptops and other mobile electronic devices, the provision of basic amenities, but also began to apply to light electric vehicles, hybrid vehicles and electric. However, due to the rapid growth of demand in the cost of lithium-ion batteries become increasingly important, due to improved energy density batteries, accidents Laptop battery safety have also been reported. Lithium-ion battery industry is currently an imminent major adjustment of the structure, dynamics and cell energy storage associated with industrial materials, processes and equipment at the direction of major technological innovations.
Using a variety of ways to increase security
Engaging the Material Safety battery, battery design, manufacture and application in many aspects, just changing the cathode material can not completely guarantee the security of the battery. Only the main material is necessary to carefully select the material of anode, electrolyte and battery separator, as a lithium-ion battery anode materials are materials of carbon, oxides of metals and alloys, graphite materials is still today a large lithium-material ion battery anode, however, its safety performance than the hard carbon materials, while the titanate spinel materials of the lithium anode has a higher security. May withstand higher temperatures using a new electrolyte membrane and the treatment of flame retardants is to improve the safety of lithium-ion IBM ThinkPad T43 battery technology.
Affect the safety of lithium-ion batteries are a major factor in the electrode materials of the drums, electrolytes and manufacturing processes and conditions of use. A cell phone used in the lithium-ion battery weighing about 20 grams, the basic requirement is that the likelihood of security incidents occurred less than one in one million, which is publicly acceptable minimum standards, the Reality is more than 1 / 10000000 small. Electric Bicycle Lithium-ion battery packs used in weight from 3 kg to 4 kg, 100 times larger than a cell phone, pure electric cars use 300 kg to 400 kg of batteries, as electric bus, or weight Battery electric trucks will be 1500 kg and 2000 kg, even more “mobile” 75,000 times ~ 100000 times. As increases battery capacity, the possibility of a significant increase in security incidents. Therefore, the battery is lithium-ion batteries, it must improve its safety performance over the single cell, asking for security indexes as high. Such as commonly used in batteries for mobile phones in the cobalt oxide and lithium use graphite as a lithium-material ion battery anodes to the positive hp Pavilion DV1000 battery post to large scale security l ‘licensure will not be guaranteed.
China started to conduct research and development of lithium-ion battery electric vehicles when there were a number of explosions and burn injuries, one of the main reasons is that the use of batteries for mobile phones are generally used in the cobalt oxide, lithium as cathode material for batteries. Then browse to the cathode material replacement for lithium cobalt oxide to address issues of safety is the driving force-type lithium-ion battery R & D a top priority. China high power lithium-security issues of ion battery in the “Tenth Five-year period” was a better solution. Using modified cathode materials of lithium manganese oxide reduces the nature of the content of lithium cobalt acid lithium as active low. Japan’s mass-produced the battery capacity of lithium manganese monomer small, as publicly reported in the 3000 Tokyo Power battery electric car for 216 13Ah lithium manganese batteries.
Lithium iron phosphate as cathode to better security
On the cathode, the lithium iron phosphate (LiFePO4) Charge-state thermal stability of the oxidizing capacity of the electrolyte level is low, with better security, can be used to make a larger toshiba PA3399U-1BRS battery. LiFePO4 theoretical capacity of 170 mAh / g, compared to the voltage 3.5V lithium metal, made of materials, the actual reversible capacity above 160 mAh / g. In comparison with other materials, lithium-ion chemical diffusion coefficient of LiFePO4 electronic conductivity below room temperature is far below that of other cathode materials, the need for reducing the size of the material, coated d Agent driver how to improve the material properties and the realization of applications use the default has introduced a low density, the volume is too great and the electrolyte of the battery more. The current research effort is to develop new methods of lithium iron phosphate synthesis and hardware has been modified to improve the overall performance of lithium iron phosphate.
The first synthesis of railway lithium phosphate JB Goodenough reaction in solid phase. This method is simple and convenient, easy to use, a longer cycle of disadvantage is that synthetic products were difficult to control the stability of the lot. How heat treatment and processing into powder, the process to prevent oxidation of bivalent iron is the synthesis of critical control points. There are many R & D team has developed the carbon thermal reduction method, co-precipitation, hydrothermal method, the method of spray pyrolysis.
At present the international community can create businesses lithium iron phosphate Valencia, A123, Phostech well. Lithium iron phosphate ongoing development of industrial enterprises are also many. According to the Internet survey, 80% of domestic cathode materials for well known suppliers of lithium batteries of foreign claims that its lithium iron phosphate during development and production of related products. And the “international professional players’ contrast, investment in R & D intensity and time point of view, is still in its infancy.
Compared to other lithium apple MacBook 13 inch battery material, lithium iron phosphate is still very young. Some people say that the battery used in power tools, it has been said that it would apply to electric bus batteries, the initial opening is the need to be encouraged.
Japan in the field of lithium-ion battery has a monopoly, Sony, Sanyo Electric, Matsushita Battery, NEC and other famous companies have built large-scale lithium-ion battery range of production, but most manufacturers also maintain and expand production of the original mark, all use their own advantages to develop lithium-ion battery of new products. Japanese New Sunshine Program in 1992 to start lithium battery-development plans of ion battery R & D funds invested over one billion U.S. dollars, access to technology and technological breakthroughs. Toyota has recently begun mass production of lithium-ion rechargeable battery, in February 2003 for the announcement of a small car “Vitz” model, the stability to withstand the test of market. Hitachi, NEC, Mitsubishi and other companies producing lithium-ion batteries used in electric vehicles and hybrid electric vehicles Bulk, Fuji Heavy Industries, Tokyo Electric Power Design for the introduction of the use of lithium manganese cathode materials for oxide-vehicle lithium-ion battery electric “R1e”, a fast charge mode, 15 minutes can be filled to 80% of the price may move around a sub-80km. Maximum speed of 100km / h. Tokyo Electric Power in 2006, then in 30 years R1e. In addition, since 2007 to import a total of about 3000. Overall, Japan remains the main country of battery technology to power its supply batteries and their mass production of key materials technology has matured, the performance was almost meet the demand for electric vehicles.