Structure and development of lithium titanate battery

Titanium acid lithium battery is made by the positive and negative plate (the positive active material for ternary lithium, negative extremely lithium titanate), membrane, electrolyte, ear, stainless steel, aluminum alloy shell, etc. Positive and negative plate is the area of electrochemical reaction, the diaphragm, electrolyte with Li + transport channel. The electrode ears have the effect of direct current.

Battery, Li + migration from the ternary lithium materials to the surface of a crystal, emerge from the positive plate material, under the action of electric field force, into the electrolyte, through the diaphragm, then through the electrolyte to migrate to the surface of the anode for lithium titanate crystal, then embedded anode material in lithium titanate spinel structure. At the same time, the electron flow through the anode aluminum foil, the ear, battery pole columns, column load, negative pole, the cathode ears flow to the cathode foil electrodes, then through the conductive body flows to the anode, and lithium titanate charge to make the balance.

Battery discharging, Li + from lithium titanate spinel structure materials, embedded into the electrolyte, through the diaphragm, then through the electrolyte to ternary lithium crystal surface, and then embedded in the ternary lithium materials again. At the same time, the electronic flow by the conductive to the cathode foil electrode, ear, battery cathode polar column, column load, the positive pole, the positive pole ear flow battery anode aluminum foil electrodes, and then by the conductive to ternary lithium anode, the balance of charge to.

Lithium titanate battery, therefore, the basic principle, is in charge and discharge process, the corresponding back and forth between lithium ion across the electrodes in embedded, complete the battery charge and discharge and supply power to load. Lithium titanate battery charge and discharge diagram as shown.

When the battery, the positive electron, lithium ion emergence, embedded in the cathode; The cathode embedded lithium ions and electron as rich lithium state. The process discharges the opposite. In Li + embedded or embedded in the process of the reaction, lithium titanate (Li4TI5O12) is a kind of ideal embedded type electrode materials, Li + insert and embedded or not has no effect on the material structure, so called "zero strain" materials, thus ensuring the good cycle performance.

Lithium titanate is the molecular structure of the two different phase Li7TI5O12 and Li4TI5O12.Produce the crystal structure and crystal structure of Li4Ti5O12 Li7TI5O12 are spinel structure, and the lattice constant change is very small, also small volume change.To avoid the charge and discharge cycle of electrode materials of structural damage caused by scaling back and forth, so as to improve the cycle performance and service life of the electrode, reduced along with the increase of cycling times bring capacity attenuation, make lithium titanate has excellent cycle performance.

Lithium titanate battery electrochemistry reaction equation:

The total chemical reaction equation is:

The architecture of the lithium titanate battery

The positive: lithium iron phosphate, lithium manganese acid, or ternary material, nickel and manganese acid lithium.

Negative: lithium titanate material.

Diaphragm: with carbon as anode of lithium battery diaphragm.

Electrolyte with carbon as anode of lithium battery electrolyte.

Battery shell: the lithium battery shell of carbon as negative.

Lithium titanate battery components and structure is introduced

Lithium titanate battery advantages

Lithium titanate battery has small volume, light weight, high energy density, good sealing performance, no leakage, no memory effect, low self-discharge rate, rapid charging and discharging, long cycle life, wide working temperature range, security and stability of green environmental protection and other characteristics, so has a very broad application prospects in the field of communication power supply.

Lithium titanate as the cathode material potential platform is as high as 1.55 V, when more than 1 V is higher than that of traditional graphite anode materials, although lost some energy density, but also means the battery is more secure. Technical expert Lou blu-ray has said that the battery fast charge when the demand for the cathode voltage is lower, but if too low, the lithium battery is easy to precipitate very reactive metal lithium, this kind of lithium ion conductive not only, also can react with the electrolyte, and then release quantity of heat, combustible gas, fire. And higher than that of lithium titanate as to 1 to 0 v voltage to avoid the negative voltage, also indirectly to avoid lithium ion precipitation, so as to ensure the safety of the battery.

Due to the lithium titanate battery can be achieved under high temperature and low temperature environment safe use, also reflects its wide temperature resistant (especially resistant to low temperature) important advantage. At present, the silver work safety of the lithium titanate battery temperature region between - 50 to 65 degrees, and common graphite cathode battery energy during temperature below 20 degrees - begin to decay, to 30 degrees charging capacity is only 14% of the total capacity, cannot work normally under the cold weather. In addition, because even if overcharge lithium titanate battery, also only 1% of the volume change, known as zero strain material, making it a very long life. Silver long Wei Yincang chairman has said that the silver long lithium titanate battery life can be up to 30 years, and the service life of the car, and ordinary graphite anode materials battery life expectancy but three to four years. Look from whole life cycle, lithium titanate battery costs less.

Lithium titanate last advantage is fast charge and discharge capability is strong, the charging ratio is high. The silver long lithium titanate battery charging ratio of 10 c, 20 c, even and common battery charging ratio of graphite anode materials is only 2 c - 4 c. Based on the characteristics of lithium titanate battery, the personage inside course of study thinks its fit the demand of new energy bus, large energy storage equipment.

Lithium titanate battery defect

Excellent safety performance makes the titanate lithium ion batteries become the study hotspot, but Li4Ti5O12 low electronic conductivity of the samples (10 to 13 S/cm) and lithium ion diffusion coefficient (10-10 ~ 10-13 cm2 / S) greatly limits the down is filled in the large range of applications. Some scholars study showed that the Li4Ti5O12 particle size of nanometer later can expand the effective reaction area and decrease the diffusion distance, thereby significantly improve material ratio of performance. But it should be pointed out that, the process of nano material particles tend to be more difficult, need high cost, difficult to achieve large-scale industrial production at present.

Lithium titanate battery will happen in the recycle gas continuously, and causes the battery pack to bulge, particularly at high temperature, the impact is negative contact, increase the battery impedance, influencing the full play of the battery performance. It is also limit the cathode material of lithium titanate is widely applied to the one of the main obstacles in the battery.

Lithium titanate battery technology development and its development direction

1. The development of lithium titanate battery technology in China

Lithium titanate battery technology in our country energy storage battery advantage of competition should possess, geographical and human conditions. Light in terms of life, and lithium titanate battery long cycle life is far better than the various types of lead-acid batteries; Its efficiency, cost, and electrochemical performance is better than sodium sulfur and flow vanadium battery system.

Li-ion battery products in major markets are portable appliances such as mobile phones and laptops. The amount of China's mobile phone and laptop is big, but most do not belong to domestic brands. Domestic lithium electricity is in portable electronics because of lithium electricity sales ability to lose in Japan and South Korea product.

However, the application of the technology of lithium titanate is a hybrid electric vehicle market, special industrial application and energy storage applications such as FM and grid voltage support, etc. These markets in the world is still in its infancy, who was unknown perfectly. Lithium titanate technology is expected to be a major player in these markets.

China's population accounts for about 1/5 of all over the world. Due to the large population, China's electric vehicles, energy storage and industrial application market is a huge market multinational companies in many countries covet. In recent years, the Chinese government attaches great importance to the development of electric vehicle and energy storage industry, all kinds of the state encourages the policy are introduced. Chinese lithium titanate battery system in Chongqing and European hybrid electric bus, Zhang Bei scenery storage demonstration baoqing station and the Shenzhen energy storage power station has been in the commercial application of data accumulated for years.

In addition, the lithium electricity industry chain upstream and downstream small already, in addition to the complete supply of battery materials and equipment manufacturing capacity, production capacity of lithium battery and Japan and Korea three points.This makes the lithium-ion battery manufacturers in China from traditional lithium electricity production transition to lithium titanate battery production has the congenital conditions.

In lithium titanate material production in China has already had a can like Sichuan Xing, Zhuhai silver lung, Huzhou micro macro, etc. There are both strength and experience of the enterprise. In respect of lithium titanate battery production stand out on behalf of the enterprise silver long Huzhou micro macro, Zhuhai, Shenzhen Bo Lei Da, Tianjin gateway, etc.

These companies have been at home and abroad, electric vehicle and energy storage preliminary set up his own market sales channels. Especially worth pointing out is Shenzhen Bo Lei has produced from material production to the battery and system integration of a series of proprietary technology and intellectual property rights, is a rare Chinese lithium electricity industry with independent intellectual property rights of the manufacturer.

2. Lithium titanate materials, batteries and battery production bottlenecks

Now that technology has many other lithium battery lithium titanate incomparable superiority, why so far a few applications in the field of China's energy industry and even the world energy? Reason has the following three aspects:

1) Lithium titanate material in the production of lithium titanate materials production in principle is not complicated. But to anode materials for lithium ion batteries, not only need to pay attention to material has appropriate specific surface area, particle size, density, and the electrochemical properties, etc., must also be able to adapt to mass production technology of lithium battery. Lithium titanate material in many traditional li-ion battery production lines can't normal production is one of the reasons of the pH value of the material for 11 or 12, strong moisture absorption.

(2) lithium titanate battery production in a matter of fact, the conventional lithium-ion battery production line directly used to produce titanium acid lithium battery products are not like just replace graphite with lithium titanate material. Lithium titanate material requirement for the humidity is much higher than conventional lithium ion battery production. In order to control the humidity, some preparation needs to be done to adjust to adapt to the special requirements of lithium titanate battery production. In addition, some production equipment also needs to make a corresponding improvement. If conditional word, best can specially designed for lithium titanate battery products to a compact structure, small volume, fully enclosed the automation of the production line.

(3) Titanate lithium battery pack unlike conventional lithium-ion batteries, the production of lithium titanate battery at home and abroad put into application in group after a period of time often see soft package of monomer battery with trace gases. These gases and fumes, fresh batteries are different. The former can through production process to remove the battery. But the latter is in the process of our battery, or under the condition of the current process is hard to avoid.

The author thinks that, to study the chemical reaction mechanism of cycle gas produces should be a good research topic. In addition, due to the lithium titanate battery technology is one of the advantages of its high power performance. Although the battery itself can bear large current charge and discharge, but the thickness of the monomer battery is still not suitable for high power applications because the battery is too thick will cause the large current generated as difficult to heat. So for high power lithium titanate battery, size large, thin, soft package cell structure is still a reasonable choice.

3. The future development direction of lithium titanate technology

Finally, the necessary comprehensive summarize lithium titanate material as the advantages and disadvantages of li-ion battery cathode, advantage: high security, long life, high and low temperature working range wide, high power, low cost, and green environmental protection. Disadvantage: lithium titanate material energy density low, water imbibition is strong, the battery produced by high environmental requirements, the production process to do the corresponding update, the new process need to invest the necessary equipment and higher requirement of humidity control, as well as the application of lithium titanate battery market has not fully open.

The page contains the contents of the machine translation.