Can the density of lithium power battery still be improved?

At present, in China’s new energy vehicle market, the power battery carried on blade electric vehicles, most of them are using battery made of ternary lithium or LiFePO4. Compared with lead acid and nickel metal hydride batteries, the energy density has been improved greatly, but it is still difficult to relieve customer’s anxiety of endurance ability. There is no doubt that the main factor that hinder the industrialization of new energy vehicles at present stage is the technical bottleneck of power battery. However, the battery capacity is difficult to improve now, reducing the weight may be a feasible way.

Can the density of lithium-ion battery still be improved?

Now, both the ternary lithium battery materials lithium iron phosphate batteries, basic is made up of four key parts, namely the positive, negative, and electrolyte membrane. An unnamed battery expert told reporters that now based on the four components of lithium battery, to improve the energy density and achieve industrialization application, is unlikely. In fact, the energy density of power battery module in 2020 reached 2020 wh/kg, from 2020 years and 5 years’ time, but can be the next generation of the industrialization of power battery has not surfaced.

Deputy director of Shanghai motor vehicle inspection center Miao WenQuan think, to improve the power battery than the technical approach of energy has a lot of: one is technology progress, today the battery technology design is relatively mature, improve battery than the energy of the space is not large; Second, the material performance of ascension, subject to their own physical and chemical properties, and ternary lithium iron phosphate as the anode, carbon materials as the cathode Lithium ion power battery It is difficult to have a big breakthrough in the energy density; Three is new material, new system, namely the development ratio can develop new materials, new power battery system will be the future power battery than the main way to significantly enhance energy.", a new technology from the laboratory to applications tend to experience many years." Miao WenQuan said. In 2020, he argues, is not a distant future, there is no see any identifying solutions, to achieve the above objectives of a new generation of power battery system are numbered. He said, at present, Japan and South Korea are studying gel battery, this is a no and diaphragm electrolyte battery, battery, could potentially bring qualitative change, but there is no news of industrialization.

Reducing the weight of battery is a feasible way

If at this stage can't effectively improve battery energy density, so if we can consider from the Angle of to the battery pack weight loss of the whole to improve the energy density? China battery industry association Zhang Min Dr Yu, told reporters that the idea is completely feasible. She said the power battery in the battery pack, the weight of the batteries in general proportion between 1/3 to 2/3, for the rest of the circuit board, shell and other accessories. If that effectively reduce the weight of these parts, while maintaining the existing energy density batteries, the energy density of the battery pack as a whole will have an obvious increase.

In 2010, before and after the power battery pack for security needs, often use a metal shell, battery pack overall energy density is very low. Later replace high polymer shell, there was a large increase energy density. Energy density Zhang Min Yu said the battery pack is a system problem, improve the energy density batteries is a direct way, but do batteries, circuit layout, reduce the body weight, enquiring for battery, is also an effective means to improve the battery energy density.

In practical application, the reporter learned that baic EV200 new energy vehicle battery box frame using aluminum alloy material, under cover with composite materials, effective weight loss tens of kilograms. Baic, deputy general manager of new energy Wang Kefeng says, by reducing the battery overall weight, can realize the vehicle weight reduction and energy density is to improve battery box of an effective means. In addition, he says, changed generally lighter materials lead to the rising cost of batteries, now Beijing new energy stepped in to the research and application for lighter, stronger lower material cost.

In future, research and development of new battery is in parallel with weight loss

According to the state council promulgated the "energy conservation and new energy vehicles industry development planning (2012-2020)," target, which are mentioned in the energy density of power battery module this year reached 150 wh/kg (converted into single cells, its energy density is about 170-190 wh/kg), power battery module in 2020 to the energy density of 300 wh/kg (corresponding to the monomer battery energy density at least more than 330 wh/kg).

Zhang Min Yu said that in order to achieve the goal of 300 wh/kg, research and development of new batteries and battery pack weight loss needs to be parallel. She introduces, power battery for assembly on the car, need to pass test, under various working conditions to ensure the safety of the certain structure. Or other material to replace steel shell with carbon fiber shell of the shell, as long as you can guarantee the strength requirement, completely feasible. Battery pack heat dissipation and soaking ability is another important index. If the battery pack and local overheating, can lead to inconsistent battery internal resistance, batteries discharge capacity drops, those who do not fully discharge batteries in a sense, is an ornament to the battery pack. “Battery pack 300 wh/kg, the energy density for battery weight loss alone may be unable to achieve, but power battery as a system, that the role of nots allows to ignore. “Zhang Min Yu said. China electric car xinqi qiao, deputy secretary-general of the committee, said on the manufacture of power battery, China doesn't lag behind foreign counterparts. But domestic enterprises are lack of basic research, the excessive pursuit of high energy batteries, should be balanced development, in the development of new materials battery at the same time, attach importance to the existing system of battery weight loss.

Weight loss of battery relies on the process of industrialization

Electric vehicle power battery now sells more expensive to baic EV200 new energy as an example, the battery cost almost the cost about half. If on this basis, the change of light materials, the cost will also rise. This is the biggest cause of many oems temporarily not using new materials. In addition, the new material is not acceptable for consumers and oems to consider a problem. In the pure electric vehicles use cost low, consumer demand for lightweight materials is not high, from another aspect also restricted the application of lightweight materials.

In the short term, for the battery "--" a little do not please painfully. Some oems to reporters, head of the report, if the industry chain is mature, new energy automobile production further amplification, is it possible to extensive use of new materials. Only 70000 allowance for half a year sales of new energy vehicles, this is indeed true. One industry expert told reporters a telling his own story.

The experts engaged in the research of new energy vehicles, so I buy an electric car use. In a reverse, accidentally ran into a wall, damage of rear bumper and rear window. He put the car back to 4 s shop repair, thought a week can be repaired, the result waited a month to fix. Also gave him a fright, maintenance of bumper and rear window maintenance costs 10000 yuan. Experts wonder, consulting, 4 s shops were told because oems output is not high, there is no spare parts, fittings such as in most of the time in a month. Because other fittings are very expensive, the maintenance is much higher than traditional cars. Experts last sigh: "because less."

Battery weight loss to the acceleration of industrialization, in fact, zoom in to a whole new energy car, also depend on the speed of industrialization. In the first half of this year, production and marketing of new energy automobile market flourish. According to the momentum, sales for the year is expected to exceed 200000 vehicles. On such a scale, industry chain will be further mature, spare parts cost is expected to decline further.

As currently envisaged, small batch demonstration operation and large-scale market operations in the middle, is far from a simple quantity accumulation. Car companies to increase investment in research and development as soon as possible the progress of technology, the threshold of the breakthrough technology and barriers, travel distance increase, rapidly diluted cost, finally realizes the infant industries in the shortest possible time to grow and mature.

All roads lead to Rome

From the current method to improve power battery energy density are limited, in addition to developing new battery, nothing more to increase the positive active material and reduce the weight of the two kinds of battery accessories weight method. For the former method can directly increase battery power, but is more of a problem, such as security decline and local overheating. After a method effect though not so intuitive, but also can achieve the purpose of the first method.

Reduce the strength of the parts but not reduce weight parts. From now the battery research and development, our country of research and application lags behind in this respect. In materials science research, we have to admit that there is a certain gap, and foreign especially in basic research and development. In addition, replacing the original with lighter materials the heavier materials, facing the rising cost of problem. In the case of a power battery is very expensive, oems in this way is unlikely.

But, look from foreign research results, looking for a kind of high strength, light weight and low cost of materials is possible. Recently, Volvo announced that the electric car battery light into the practical testing, Volvo, said the new battery materials cheaper, and more environmental protection. If all the electric vehicle battery replacement into this kind of new materials, can reduce vehicle weight more than 15%, effect is obvious.

Improve system by battery rearrange the layout is also one of the effective means of energy density. Through the study of cell size design, for example, match the vehicle arrangement, more efficient to place more battery, so that the battery box volume, increase the number of batteries, travel distance to achieve a longer. In a word, to improve the battery energy density, can through a variety of methods to achieve them.

In addition to a long-term planning, the top priority for automobile enterprises currently is to develop more reliable and economical lightweight materials. During the technical bottleneck period of battery technology, a design concept of lightweight is a major thrust of electric vehicle technology revolution. Whatever in future new battery is made up of what kind of material, the basic composition of the battery pack material can be universal, it may not benefit very much in a short term, but in the long term, the basic research is not in vain.

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