Deep analysis of lithium iron phosphate batteries and ternary lithium batteries

Lithium iron phosphate battery: refers to lithium battery using lithium iron phosphate as the anode material. Its characteristic does not contain the valuable elements, such as cobalt. The raw material prices are low. Phosphor and iron has abundant resources in the earth. There would be no problem of material. Its working voltage is (3.2 V) moderate. Large capacitance under unit weight (170 mah/g), high discharge power, fast charge, long cycle life, high stability under high temperature and high temperature environment.

Advantages compared to the more common on the market and cobalt acid lithium manganese acid lithium batteries, lithium iron phosphate batteries at least has the following five advantages: higher safety, longer service life, does not contain any heavy metals and rare metals (low) cost of raw materials, support rapid charging, wide working temperature range.

Disadvantages of lithium iron phosphate has some defects on the performance, such as low tap density and compaction density, leading to a lower energy density of lithium ion batteries; The preparation of material cost and battery manufacturing cost is higher, battery low yield, poor consistency; Poor product consistency; Intellectual property rights.

The ternary polymer lithium battery: the anode materials using nickel cobalt manganese acid lithium (Li (NiCoMn) O2) ternary cathode material of lithium battery. According to Tsinghua university ming-gao Ouyang explains: the survey of "three yuan" referred to in the materials, refers to the positive electrode is 3 yuan, the anode is graphite is usually "three yuan power battery". In practical application in the research and development, and three yuan is a kind of positive, negative is lithium titanate, commonly referred to as "lithium titanate", its performance is safety, long service life, does not belong to common says "ternary material."

Advantages of ternary lithium battery energy density is high, the cycle performance is better than normal cobalt acid lithium. At present, as incremental improvements were made in the formulation and perfect structure, nominal voltage of battery is 3.7 V, on the capacity has been reached or exceed cobalt acid lithium battery level.

Faults ternary material power lithium batteries are mainly aluminum nickel and cobalt acid lithium batteries, nickel cobalt manganese acid lithium battery, etc., due to the high temperature structure of the aluminum nickel and cobalt is not stable, lead to high temperature and poor safety, and high pH make the monomer easily bilge gas, causing danger, the cost is higher.

Takeaway: in contrast, three yuan polymer lithium battery indeed have a more superior to the characteristics of lithium iron phosphate batteries, but why it's development by the block? The key of the development of new energy vehicles, also is the key to haunt the mobile digital products, the development of the battery. How in the case of safety guarantee battery technology can satisfy the growing consumer demand, is not only the automotive related industry of science and technology personnel, or the pursuit of scientific research workers in all areas

Said to buy new energy vehicles, may is most consumers remember the first time the "preferential policy", although it is a bit awkward but it is quite true. In the domestic sales environment, new energy vehicles to open the situation, not just because of the sense of "environmental protection" such a long way. New energy vehicles on the price and the maintenance cost advantage is indeed attracted most of the present stage still is given priority to with transport costs of the love of consumers.

However the footsteps of some consumers may for some reason a temporary stop to the curiosity of new energy vehicles, because how much will be the new energy car events concerned of various kinds of spontaneous combustion. This is where the author today why to write this article. Must know do not know the root of the new energy vehicles, energy module, and don't understand matters need to pay attention to in the process of use, and actually buy a ticking time bomb in the side and no different.

Lithium iron phosphate battery: mature but is not enough

Electrode materials for lithium iron phosphate is the safety of lithium ion battery cathode material, combined with its cycle life reached more than 2000 times, the standard charging rate (5 hours) to use, can achieve the cyclical characteristics of 2000 times, coupled with the industry mature and technology threshold and the decline in the price, make many manufacturers for a variety of factors to consider using lithium iron phosphate batteries. The rise of new energy vehicles, so to speak, and lithium iron phosphate batteries are not or points.

Lithium iron phosphate batteries, however, there is a fatal weakness, that is the low temperature performance is poorer, even if the nano and carbon coating to solve this problem. Research has shown that a capacity of 3500 mAh battery, if working in a - 10 ℃ environment, after less than 100 times charging and discharging cycle, power attenuation sharply to 500 mAh, basic is discarded. This to China's vast, low temperature in winter is more comprehensive, the state of the union is not a good thing indeed.

In addition, the preparation of material cost and manufacturing cost is higher, batteries battery low yield, poor consistency, it also lead to a lot of pure electric vehicle battery life does not reach the nominal value of important reasons. Therefore, we can see that many of the nation's new energy vehicles (both electric and hybrid electric), or are some of the new energy vehicles is cheap, will choose the lithium iron phosphate battery for different reasons. The lithium iron phosphate battery, as it were, to use, the new energy automobile production floor and promotion, has an indelible based role.

In contrast, the ternary polymer lithium battery indeed have a more superior to the characteristics of lithium iron phosphate batteries, but why it's development by the block?

The ternary polymer lithium battery: restless in the future

Ternary polymer lithium battery is correct material using nickel cobalt manganese acid lithium (Li (NiCoMn) O2) ternary positive electrode material of lithium battery, the ternary composite cathode material precursor products, is the cobalt nickel salt, salt, manganese salt as raw materials, in the proportion of nickel cobalt manganese can according to the actual need to adjust. The ternary lithium battery energy density is bigger, but security is often suspect.

Is there such a reason is that even if the two materials will be in when you arrive at a certain temperature decomposition, ternary lithium materials can occur in the lower 200 degrees decomposition, and lithium iron phosphate material is around 800 degrees. And chemical reaction of the ternary lithium materials more intense, can release oxygen, under the effect of high temperature electrolyte rapid combustion, a chain reaction. Say simply, it is the ternary lithium material than lithium iron phosphate material more easy to catch fire. But it is important to note that we mentioned is the material, rather than batteries has become a finished product.

Because of the ternary lithium materials have such security hidden danger, so the manufacturer also in efforts to curb the direction of the accident. According to the properties of the ternary lithium materials easily pyrolysis, manufacturers (OVP) in the overcharge protection, discharge protection (UVP), over temperature protection (OTP), the over-current protection (OCP) composition among the link will be under a lot of kung fu.So more spontaneous combustion is should consider whether the function of the manufacturer in this a few link in place, rather than simply isolate.

So the usage of these two kinds of battery now is how? Let's focus on a set of data. Last November, lithium iron phosphate battery electric bus installed capacity up to 64.9%, the ternary lithium battery installed capacity is only 27.6%.On the contrary, in the pure electric passenger car market, the ternary lithium battery installed capacity of more than 76% in November last year.

It can be seen that the ternary lithium battery energy density greater preponderance, should be to for future car new energy storage device. Now related security incidents in the popularization of new energy vehicles is still in its infancy, is a good thing. A lot of new energy vehicles related businesses in order to be able to seize market and obtain the double goal of policy support, to broaden the technical requirements, mass production cannot stand the repeated use of the energy components for a long time. Car work environment is harsh, use these parts for a long time, the reason of safety accidents is greatly increased.

So we can think in China ministry of industry and information technology on electric vehicle c equipment department chief priests published a picture of wood for three yuan bus to evaluate the safety performance of lithium-ion batteries, is interested in from the relevant state department on a standard definition of policy, to promote the industry standard. Both to consumers and manufacturers, has a very positive significance in the future. So there's no need for online one-sided see ternary lithium battery safety accidents can message material is danger, the key lies in how to firmly in control.

Different types of new energy car battery: unified requirements

Said these batteries, the author thinks that in the case of new energy vehicles also need to with all of you a brief introduction of the role of the battery in the vehicle. Consumers buy pure electric vehicles, after all, still in the minority, more friends concern is a hybrid car. And hybrid cars can be divided into three types: strictly ordinary hybrid vehicles, plug-in hybrids and a hybrid cars.

The arrangement of the above three kinds of car battery capacity since the childhood was just ordinary hybrid < plug-in hybrid cars increase program or less a hybrid car. Ordinary hybrid non-rechargeable batteries, battery used to start and throttle state; Plug-in hybrid car batteries in ordinary enlarged capacity on the basis of a hybrid car batteries and rechargeable, have better speed and fuel economy ability; And increase the program used to drive the motor power hybrid engine, more inclined to pure electric vehicles.

The advantages and disadvantages of each three hybrid models in the main in the present stage is to ordinary hybrid and plug-in hybrid. Just because of three kinds of hybrid traits are for battery life and working environment in common, so either buy what model of hybrid cars, consumers have to pay more attention to the related parameters, such as battery material, use the environment and the best working state, etc. At the same time, manufacturers should also in the design process strictly control the battery quality and related security Settings, ensure the safety of the use of high efficiency.

Is the key to the development of new energy vehicles, whether to use the experience to rival or even beyond the traditional internal combustion engine car, at the same time in the link of purchase and after-sales whether has the advantage of better. In my opinion, the key of the development of new energy vehicles, also is the key to haunt the mobile digital products, the development of the battery. How in the case of safety guarantee battery technology can satisfy the growing consumer demand, is not only the automotive related industry of science and technology personnel, or the pursuit of scientific research workers in all areas.

Lithium iron phosphate batteries

Eight big advantage

To improve the performance of security

Lithium iron phosphate crystals in P - solid O key, difficult to decompose, even in high temperature or overcharge when also won't like cobalt acid lithium structure collapse fever or strong oxidizing substances, thus having good security. A report pointed out that the practice of acupuncture or short circuit experiment found combustion phenomenon in a small number of samples, but no one explosion occurred, and overcharge experiments using several times greatly beyond their discharge voltage of high voltage charging, found that there are explosive. Even so, the overcharge safety than common liquid electrolyte cobalt acid lithium batteries, has greatly improved.

The improvement of the life

Lithium iron phosphate battery refers to the use of lithium iron phosphate as the anode material of lithium ion battery.

Long life cycle life of lead-acid battery in about 300 times, the highest is 500 times

Lithium iron phosphate batteries, and lithium iron phosphate power battery, cycle life reached more than 2000 times, the standard charging rate (5 hours) to use, can reach 2000 times. With the quality of the lead-acid battery is "new half a year, half a year, maintenance, maintenance and half year old", at most 1-1.5 years, while the lithium iron phosphate batteries used under the same conditions, the theory of life will reach 7 ~ 8 years. Comprehensive consideration, the price performance ratio in theory for lead-acid battery more than four times. Large current discharge can be as big 2 C fast charge and discharge current, under the special charger, 1.5 C can make battery charging 40 minutes, starting current can be up to 2 C, lead-acid battery is the performance.

High temperature performance is good

Lithium iron phosphate can reach 350 ℃ to 500 ℃ and the electric peak and cobalt acid lithium manganese acid lithium only at about 200 ℃.Wide range of operating temperature (20 c -- - + 75 c), have a high temperature resistant properties of lithium iron phosphate can reach 350 ℃ to 500 ℃ heating peak lithium cobalt and lithium manganese acid and acid only at about 200 ℃.

The large capacity

With greater than ordinary battery (lead-acid, etc.) capacity.5 ah ah - 1000 (monomer)

No memory effect

Rechargeable battery under the condition of are often filled with not to put the work, the capacity will quickly lower than the rated capacity values, this phenomenon is called memory effect. Memory like nickel metal hydride, nickel cadmium battery, and lithium iron phosphate batteries do not have this phenomenon, the battery no matter in what condition, can use increases with the increasing charge, do not need to first put the recharging.

Light weight

The same specification of lithium iron phosphate battery capacity volume is two-thirds the size of lead-acid battery, weight is the 1/3 of lead-acid batteries.

Environmental protection

The battery is generally regarded as do not contain any heavy metals and rare metals (nickel metal hydride battery of rare metals), non-toxic (through the SGS certification), no pollution, comply with European RoHS, is absolutely green battery certificate. So the lithium battery is favored by the industry, mainly environmental considerations, so the battery and listed in the "863" during the tenth five-year national high-tech development plan, has become the national key support and encourage the development of project. With China's accession to the WTO, Chinese exports of electric bikes will increase rapidly, and into Europe and the United States of electric bicycle has asked equipped with battery from pollution.

But experts say, lead-acid battery caused by environmental pollution, mainly in non-standard production process and recycling. By the same token, the lithium battery belongs to new energy industry is good, but it can't avoid the problem of heavy metal pollution. In the metal material processing such as lead, arsenic, cadmium, mercury, chromium is likely to be released into the dust and the water. The battery itself is a kind of chemicals, so is likely to produce two kinds of pollution: one is the production engineering process of waste pollution;2 it is scrapped after the battery pollution.

Lithium iron phosphate battery also has its disadvantages: low temperature performance is poor, for example, tap density is small, the anode materials such as volume of lithium iron phosphate battery capacity than cobalt acid lithium and other lithium ion battery, so don't have an advantage in terms of micro cells. And when used for power battery, lithium iron phosphate batteries and other batteries, battery consistency issues needs to face.

The contrast of power battery

Is currently the most promising application in power type lithium ion battery cathode material basically has modified lithium manganese acid (LiMn2O4), lithium iron phosphate (LiFePO4) and nickel cobalt manganese acid lithium (Li (Ni, Co, Mn) O2) ternary material. Nickel cobalt manganese acid lithium cobalt ternary material due to the lack of resources and nickel and cobalt into high price fluctuation and large, is generally believed that it's hard to become the electric car with the mainstream of power type lithium ion battery, but can and spinel lithium manganese acid mixed in a certain range.

Industry application

Coated carbon foil bring lithium electricity industry technical innovation and industry promotion

Improve lithium electricity product performance, improve the discharge ratio [1]

As the requirement of domestic battery manufacturers of battery performance is increasing day by day, generally recognized by the domestic new energy battery materials: conducting materials and conductive coating aluminum foil/copper foil.

Its advantage lies in: in the treatment of battery materials, often have high rate charge and discharge performance is good, bigger specific capacity, but the cycle stability is poorer, attenuation serious wait for a reason, have to do choose to give up.

Product application, golf in the charter in the battery pack

Product application, golf in the charter in the battery pack

This is a magical coating, would improve the performance of the battery, into a new era.

Conductive coating is good by decentralizing nano conductive graphite coated particles, etc. It can provide excellent static conductivity, it is a layer of protection energy absorption layer. It can also provide a good cover protection performance. Coating with water and solvent resistance, can be used in aluminum, copper, stainless steel, aluminum and titanium plate.

Coated carbon coating on the performance of lithium-ion batteries with the following promotion

1. Reduce the battery internal resistance, inhibition of charge and discharge cycle in the process of dynamic resistance increase;

2. Improve the consistency of the battery pack, decrease the cost of the battery pack;

3. Improve the active material and fluid collection of glue adhesion, reduce the pole piece manufacturing cost;

4. Reduce the polarization, improve the rate performance, reduce the heating effect;

5. To prevent the electrolyte to set fluid corrosion;

6. The comprehensive factor and prolong the service life of the battery.

7. Coating thickness: conventional single 1 ~ 3 microns thick.

Japan and South Korea in recent years, the main development in modification and nickel cobalt manganese acid lithium manganese acid lithium ternary material as the anode material of power type lithium ion battery, such as Toyota and Panasonic EV energy of a joint venture company, new kobe motor, NEC, Hitachi, SONY, Sanyo, Samsung, LG, etc. The main development of the anode materials for lithium iron phosphate power type lithium ion battery, such as A123 systems, Valence, but the major automobile manufacturers in the PHEV and EV is the choice of manganese base power type lithium ion battery cathode material system, and it is said that the A123 company in the field of consideration into manganese acid lithium materials, and Germany and other European countries mainly adopt the battery company cooperation with other countries to develop electric vehicles, such as Daimler and French Saft alliance, Volkswagen of Germany and Japan Sanyo cooperation agreement, etc. Currently Volkswagen of Germany and France's Renault sa with the support of their governments are development and production of power type lithium ion battery.

The page contains the contents of the machine translation.