Fast charging technology of lithium iron phosphate battery

Quick charge as the most important technology of new energy vehicles development path, its range for alleviate anxiety, and reduce the charging time effect is remarkable, therefore many automakers and battery enterprises have become the market selection.

At the end of 2016 the new energy vehicles subsidies adjustment scheme, the quick charge type of pure electric bus is as a separate product segment, and give the detailed subsidy standard: according to the bus capacitance may obtain 3000 yuan/Kwh, at the same time, according to the "3 c to 5 c and 5 c - 15, 15 c + c" three grades of quick charge ratio respectively 0.8 times, 1 times, 1.4 times.

In this context, such as Foton, Yutong, Xiamen Jinlong mainstream automakers and Ningde, Walter, Unita solid, micro macro power, etc. power battery enterprises have begun to increase the layout in the field of quick charge.

And technically, although the scientific community and spread some research or new materials can greatly enhance the battery energy density of good news, but in actual production application, for reasons of cost, technology, process and security, life is still a major factor restricting the development of new energy vehicles. Before a revolutionary breakthrough in battery technology has not yet chosen quick charge to relieve the low range of defects of new energy cars, is a good way to a different approach.

In fact, fast filling in the application of power battery is already proliferated. Over the technology, in fact, all roads lead to Rome, the core of quick charge technology is in does not affect the life of the batteries and security under the premise of through chemical system and design optimization, accelerate the lithium ions in the speed of moving the cathode.

General chemistry system of battery cathode when quick charge will be by-products, affect the circulation and the stability of the batteries. Solve the obstacle of the general solution is, through the use of special design of the cathode material (such as soft hard carbon, carbon, carbon coated graphite, etc.) to make the cathode have the ability to withstand fast filling. For just as the anode material of lithium ion source, in fact, there is no requirement, as long as it can provide enough lithium ions are theoretically can be used as the anode.

Although fast charging technology, but also ensemble to specific application situation. Inventory the mainstream quick charge batteries on the market, the author according to the battery material divided into phosphoric acid iron battery, titanium acid lithium battery, manganese acid lithium battery three types.

Someone said that the lithium iron phosphate is not suitable for quick charge, because of its electrical conductivity is not very good, quick charge when the fever. But this is just for pure phase lithium iron phosphate material is concerned, after grain refinement, carbon coated surface, cell elements after doping with good ions and electron transfer rate, is suitable for fast charging. And lithium iron phosphate phosphorus high security, high heat stability, and the characteristics of long cycle life, let him be quick charge of good options. The current domestic focus is on lithium iron phosphate of quick charge technology enterprises represented by Ningde Tamar era and Walter.

Ningde era as a lithium iron phosphate batteries on behalf of the enterprise, on the quick charge way has its own quite mature system. Ningde age is only a battery on the underlying national enterprise. China and South Korea have resources internationalization, the internationalization of the customer and talent internationalization. Super enterprise human resources is abundant, the R&D team, from research and development design, to production, and then to test validation, put into production, has powerful resources support, laid the three advantages of safe, reliable and durable products.

Ningde era technology quick charge expert Dr Wang Sheng wei in the "2016-2017 China passenger car industry development peak BBS" on its quick charge technology are introduced. Developed for the anode, Ningde era "super electronic network technology, makes the lithium iron phosphate has excellent electronic conductivity, can reach 1000 times of that of three yuan, and the positive electrode of the lithium iron phosphate for the quick charge battery high safety and reliability of the system.

Ningde era adopted, for example, in the anode graphite surface "fast ionic ring" technical modification, after modification of graphite/super quick charge and the characteristics of high energy density, quick charge when the cathode no by-products, so greatly improve lithium ion in the graphite layer embedded speed, make its have 4 to 5 c quick charge ability, achieve 10-15 minutes fast charge, and can guarantee the energy density of the system level above 70 wh/kg, 10000 times the cycle of life.

In addition, the current development of Ningde era quick charge product, with independent research and development of thermal management system, fully recognize the fixed chemical system under different temperature and SOC "health charge interval", greatly broaden the operating temperature of the lithium battery. When the battery is in the north of the cold winter, the water heating system in low temperature heating for batteries, batteries temperature requirements, namely open quick charge mode; Meet the south the sweltering heat of summer, the system automatically batteries to call thespecial, water cooling system to cool batteries, truly "the whole climate" quick charge.

Same as a representative of the domestic lithium iron phosphate battery enterprise, Shenzhen walter m battery co., LTD., is the earliest successful power battery research and development of new energy cars, and take the lead to achieve the scale of production and batch application national high and new technology enterprise.

Walter, director of the institute m batteries Xu Hui at interview revealed Walter quick charge on talents. On the positive, Walter the smaller particle size of the use of lithium iron phosphate, common on the market at present the lithium iron phosphate particle size between 300 ~ 600 nm, and Walter m only 100 ~ 300 nm, lithium iron phosphate lithium ion will have faster migration, so to be a greater ratio of current charge and discharge.

In extreme is negative with smaller particle size of artificial graphite carbon coated: small size is good for lithium ions from and embedded; Carbon coating can optimize the battery cycle life improve, microporous carbon structure conducive to the adsorption and liquid electrolyte to improve cycle life.

Security, first of all, the lithium iron phosphate itself has good thermal stability, namely under the condition of the thermal runaway emanate heat materials smaller than three yuan, only about a quarter. Then on, groups, etc. of the batteries multiple safety protection. Walter m battery, cylindrical structure is adopted, and in regular safety device is equipped with ventilation pipe installation and snap open the device. Vent device can guarantee the balance of internal pressure, there will be no batteries in the local high pressure lead to the risk of battery explosion; And snap open device in battery overcharge, over-current, overheating, produce gas will disconnect circuit, end inside the battery electrochemistry reaction, when the internal pressure reaches a certain value to gas emission, and won't cause explosion.

The page contains the contents of the machine translation.