Battery Electric
Lithium ion Battery Material Properties and The Battery Safety
Current lithium ion battery has used in mobile phones, laptops, cameras,and more other mobile electronic devices. basic power has been used in electric and hybrid electric vehicle light.However, due to the rapid growth in demand for lithium ion battery, the cost of the battery become a protruding problem,and because the battery energy density,battery's safety accident also reported .Current lithium ion battery industry will occur on the structure adjustment, power and storage battery industrialization with material, process and equipment to the major technical innovation development.
Using a variety of methods to improve safety
Involving the safety of battery materials, battery design, manufacturing and application in many aspects, simply change the cathode material can not completely guarantee the safety of the battery. Only the main materials we should carefully select the anode material, electrolyte and battery separator, if used as anode material for lithium ion batteries with carbon materials, metal oxides and alloys, graphite material is still today a major lithium-ion battery anode material but its safety performance than the hard carbon materials, and lithium titanate spinel anode material has a higher security. Resistant to higher temperatures using a new type of flame retardant electrolyte membrane and processing is to improve the safety of lithium-ion xps m1530 battery technology means.
Affect the safety of lithium-ion batteries are the main factors in battery electrode materials, electrolytes and manufacturing processes and use conditions. A cell phone with a lithium-ion battery weighing about 20 grams, basic requirement is the probability of security incidents is less than one millionth, which is socially acceptable minimum standards for the public, the reality is more than 1/10000000 Huanyao small. Electric bicycle lithium ion battery used in the weight of 3 kg to 4 kg, 100 times bigger than cell phones, electric cars will use 300 kg to 400 kg of batteries, as electric buses and electric vehicle battery weight will be large is 1500 kg to 2000 kg, it is "Cell Phone" 75,000 times the ~ 100 000 times. As the battery capacity increases the likelihood of a substantial increase in security incidents. Therefore, the power battery made of lithium ion batteries, they must improve their safety performance, the greater the individual cells, required to reach the safety index is also higher. Such as the commonly used cell phone batteries in use lithium cobalt and graphite as lithium-ion batteries and anode materials, large scale after the battery safety can not be guaranteed.
When our country started to carry out research and development of lithium-ion battery electric vehicles there have been a number of explosive and incendiary incidents, A major reason is the use of Lithium cobalt oxide which usually used in mobile phone batteries as a battery anticathode materials. Was looking for an alternative cathode material for lithium cobalt oxide to address the security issue is the power type lithium ion battery R & D a top priority issue. China's high-power lithium-ion battery safety issues in the "15" period, was a better solution. Using handwriting fluorescent board modified lithium manganese oxide cathode materials reduced, activity of lithium content is lower than that of lithium cobalt oxide. Japan's mass-produced single-capacity lithium manganese oxide is not, as publicly reported for Tokyo Electric Power Car 3000 216 13Ah batteries for the lithium manganese batteries.
Lithium iron phosphate security to do better as Anode
The cathode, the lithium iron phosphate (LiFePO4) charge state of high thermal stability, oxidation of the electrolyte is low, with better security, more battery can be used to do. LiFePO4 theoretical capacity of 170 mAh / g, compared to lithium voltage of 3.5V, made of materials can exceed the actual reversible capacity 160 mAh / g. Compared with other materials, lithium ion chemical diffusion coefficient in LiFePO4 low electronic conductivity at room temperature far lower than other cathode materials, need to reduce the material size, method of coating conductive agents to improve performance and achieve application materials bring the defect is low density, cell size is too large and more than the amount of electrolyte. The current research focus is to develop new lithium iron phosphate synthesis and modification of materials to improve the overall performance of lithium iron phosphate.
The first synthesis of lithium iron phosphate way JB Goodenough Solid State Reaction. The method is simple, easy to operate, the cycle of disadvantage is the synthesis of longer, more difficult to control the stability of the product batch. How the process of heat treatment and powder processing to prevent oxidation of divalent iron synthetic critical control points. There are a lot of R & D team developed the carbon thermal reduction method, coprecipitation, hydrothermal, spray pyrolysis method.
The international production of lithium iron phosphate can the enterprises Valence, A123, Phostech so. Lithium iron phosphate with an ongoing industrial development of many enterprises. According to the Internet survey, 80% of domestic well-known cathode materials for lithium battery suppliers of external claims that its lithium iron phosphate-related products during development and production. And "international professional players," contrast, from the research and development efforts and time put into perspective, still in its infancy.
Compared to other lithium battery material, lithium iron phosphate is still very young. Some people say that the battery used in electric tools, it is said to be used with the battery electric bus, the initial development is to be encouraged.
Japan in the field of lithium-ion battery monopoly, Sony, Sanyo Electric, Matsushita Battery, NEC and other famous companies have built large-scale lithium-ion battery production line, and most manufacturers in addition to maintaining and expanding existing production of foreign brands, are use their own advantages to develop lithium-ion battery of new products. Japan's New Sunshine program started in 1992 that lithium ion battery car development program, R & D funds more than one billion U.S. dollars, access to technology and technological breakthroughs. Toyota has started mass production of automotive lithium-ion rechargeable battery, for listing in February 2003 a small car "Vitz" part of the model, stability has withstood the test of the market. Hitachi, NEC, Mitsubishi and other companies mass produce lithium-ion batteries used in electric vehicles and hybrid electric vehicles, Fuji Heavy Industries introduced the design for the Tokyo Electric Power lithium manganese oxide used as cathode material for lithium-ion dell studio xps 13 battery electric vehicle "R1e", fast charge mode, 15 minutes full of 80%, 1 charge, can run about 80km. Maximum speed of 100km / h. Tokyo Electric Power in the year 2006 and then into 30 R1e. In addition, since 2007 a total import of about 3000. Overall, Japan remains the country's leading battery technology, its power and its key materials, battery production technology has matured, performance has almost met the demand electric vehicles.
