Which research institute makes lithium battery well？

"The lithium battery", is a kind of lithium metal or lithium alloy anode materials, the use of water electrolyte solution of the battery.Lithium battery as early as 1912 by GilbertN. Lewis is put forward in this study.In the 1970 s, M.S.W hittingham and began to study are put forward lithium ion batteries.Due to the lithium chemistry is very lively, making lithium metal processing, storage, use, very high demand on the environment.So, the lithium battery has not been applied for a long time.With the development of science and technology, the lithium battery has now become the mainstream.

Lithium battery can be roughly divided into two categories: lithium battery and lithium ion batteries.Lithium ion battery does not contain lithium metal state, and can be recharged.The fifth generation of rechargeable battery product lithium battery was born in 1996, its security, specific capacity, self-discharge rate and cost performance is better than that of lithium ion batteries.Because of its high technical requirements limit, now only a few countries in the production of this kind of lithium battery.

The earliest application of lithium-ion batteries in the cardiac pacemaker.Lithium battery self-discharge rate is extremely low, the advantages of discharge voltage flat, which makes the pacemaker implantation in the human body for a long time operation without recharging the batteries.Lithium batteries tend to have higher than the nominal voltage of 3.0 v, is more suitable for integrated circuit power supply.Manganese dioxide batteries, is widely used in calculators, digital camera, a watch.

In order to develop more excellent performance of varieties, people of various materials are studied, so as to create an unprecedented products.

Sony in 1992 successfully developed lithium-ion batteries.Its practical application, make people's mobile phone, notebook, calculator carry type electronic equipment such as less weight and volume.

1, in the 1970 s, M.S.W exxon hittingham using titanium sulfide as the anode material, metallic lithium as negative material, made the first lithium battery.

2, 1980, J.G oodenough discovered cobalt acid lithium can be used as lithium ion battery cathode material.

3, 1982, university of Illinois institute of technology (theIllinoisInstituteofTechnology) R.R.A garwal and J.R.S elman found embedded lithium ion has the properties of the graphite, the process is quick, and reversible.At the same time, made of metallic lithium lithium batteries, much attention has been paid to its safety problems, so people try to take advantage of the characteristics of lithium ion embedded graphite production of rechargeable batteries.The first available lithium-ion graphite electrode successfully trial-produced by bell LABS.

4, 1983 m. hackeray, J.G galaxite oodenough and others found to be excellent cathode material, with a low price, stable and good conductive lithium, guide performance.Its decomposition temperature is high, and oxidation is far lower than the cobalt acid lithium, even if a short circuit, over charge, also can avoid the risk of combustion and explosion.

5, 1989, arjun anthiram and J.G oodenough anionic polymerization is found that the positive will generate higher voltage.

6, 1991, SONY released the first commercial lithium-ion batteries.Subsequently, lithium ion batteries have revolutionized the face of consumer electronics products.

Padhi and Goodenough discovered 7, 1996 has olivine structure of phosphate, such as lithium iron phosphate (LiFePO4), more superiority than traditional cathode material, therefore has become the mainstream of the anode materials.

As digital products such as the widespread use of mobile phones, laptops and other products, lithium-ion battery with excellent performance is widely used in such products, and gradually to other areas of application development products.In 1998, tianjin institute of power began commercial production of lithium ion battery.Traditionally, people called the lithium ion battery is lithium battery, but the two batteries are not the same.Lithium ion battery has become the mainstream.

Harbin Institute of Technology, big, xiamen university, central south, zhengzhou light industry.

Since always,Power batteryRoad there is a big controversy, and therefore, manganese acid lithium, lithium iron phosphate ternary information have chosen road.Domestic power battery road is given priority to with lithium iron phosphate, but follow the tesla popular all over the world, the data of three yuan road has caused a boom.High safety.The lithium high potential, not generation dendritic, and at the time of charging and discharging, high thermal stability exists;Coated barrier can charge the battery quickly.Charge and discharge, swelling volume, fluid absorption ability;

Lithium, atomic number 3, atomic weight of 6.941, it is the lightest of alkali metal elements.In order to improve safety and voltage, the scientists invented the graphite and cobalt acid lithium materials such as to store lithium atoms.The molecular structure of these materials, formed the nanometer level of small storage grid, can be used to store lithium atoms.In this way, even if the battery shell is broken, and oxygen to, also because of too much oxygen, into these small store, making lithium atoms will not avoid contact with the oxygen blast.

Lithium battery core overcharge to voltage is higher than 4.2 V, will start to produce side effects.Of charging the higher the pressure, the higher the risk also follow.Lithium batteries voltage higher than 4.2 V, the anode materials within less than half the number of lithium atoms left, store usually break down at this time, let the battery capacity to produce permanent decline.If continue to charge, due to the storage of the cathode has been full of lithium atoms, subsequent anode materials of lithium metal accumulation in the surface.These lithium atoms from lithium ion to the cathode surface to grow in the direction of the dendritic crystal.The lithium metal crystal through the diaphragm paper makes is negative short circuit.Sometimes in short circuit batteries before the first explosion, this is because in the process of overcharge, electrolyte materials can produce gas cracking, such as making the battery shell or blow up pressure valve is broken, and let oxygen in and accumulation in the lithium atoms on the surface of the cathode reaction, then exploded.

Therefore, lithium batteries, be sure to set the upper limit of voltage, can simultaneously to the battery life, capacity, and security.The ideal maximum charging voltage of 4.2 V.Lithium batteries discharge voltage will be lower limit.When the batteries voltage below 2.4 V, part of the material will begin to be destroyed.And because the battery self-discharge, put the more the longer the voltage is low, therefore, discharge when had better not to 2.4 V.Lithium battery discharge from 3.0 V to 2.4 V during this period, the release of energy accounted for only about 3% of the battery capacity.Therefore, is an ideal discharge cut-off voltage of 3.0 V.Charge and discharge, in addition to the limit of voltage and current limits can also be necessary.When the current is too large, lithium ions to enter the store, would gather in the material surface.

After these lithium ion for electronic, can produce lithium atoms in the material surface crystallization, this has to do with the overcharge, will cause the risk.One thousand battery shell is broken, and would explode.Therefore, the protection of lithium ion batteries, to include at least: charging voltage upper limit, lower limit discharge voltage, and current limit.generalLithium battery packInside, in addition to the lithium battery core, there will be a piece of protection board, the protection board is mainly to provide all three.Protection board, however, these three protection is obviously not enough, lithium battery explosion or disengaged from around the world.To ensure the safety of the battery system, the battery must be the cause of the explosion, a more careful analysis.

Explosion type analysis battery core type can be summarized as external short circuit, internal short circuit and overcharge 3 kinds.The external refers to the batteries of the external, contains a battery pack and poor internal insulation design caused by short circuit.When external short-circuited batteries, electronic components and failed to cut off the circuit, batteries inside will produce heat, caused part of the electrolyte vaporization, the battery shell support.When high battery internal temperature to 135 degrees Celsius, good quality paper, diaphragm will close pores, electrochemical reaction termination or near end, current, temperature is falling slowly, then avoid the explosion occurred.But the pores close rate is poor, or pores do not close the diaphragm paper, can let the battery temperature continues to rise, more electrolyte vaporization, finally the battery shell burst, and even to increase the battery temperature to make the material combustion and explosion.Internal short circuit is mainly because of the copper foil and aluminum foil burr in the diaphragm, or lithium atoms of dendritic crystal worn out by the diaphragm.

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