How do we think of the decline of dynamic lithium-ion batteries?

　　Author ：Iflowpower – Portable Power Station Supplier

According to the data released by the Interim Association, the production of new energy vehicles in the first half of 2018 completed 413,000 vehicles and 412,000 units, up 84.9% and 111.6% year-on-year.

The first half of the year is far better than the first few years. Among them, in the sales of new energy vehicles in June, the new energy passenger car, the pure electric passenger car occupied more than half of sales, accounting for 63%. Xu Haidong, the Secretary-General of the SMA, said that the production of new energy vehicles in the first half of this year is far better than in the same period in previous years.

It is expected to maintain a good development situation in the second half. The previous judgment has exceeded 1 million production and sales. New energy electric vehicles are a hot word under the moment, and their environmentally friendly and energy saving is characterized by people, and the existence of subsidy policies has made more and more families who wish to purchase electric cars.

The outlook of electric cars is very beautiful, but the problems it exist are also real in front of us. The first is a short problem of endless mileage. Although the subsidy of new politics, the models of the subsidies of the renewal, the models of the models, the models of the models below 300 kilometers or less, and the models below the 150 kilometers or less, and there is no amount of money, as if to be promoted to a certain extent.

The car company launched a larger battery model, but there is a distance between actual and ideals. For example, a model declares that 300 kilometers of battery life, it is to achieve the ideal battery life under a specific driving condition, and drive air conditioner, open air, low temperature environment in our daily life, it Breeding mileage will be big discount. The second is difficult to charge, and the charging is slow.

In the case of lagging behind domestic charging facilities, charging is a major problem facing electric vehicles. The lack of charging piles in public places has seriously affected electric vehicles. In addition, most of the charging piles are slowly filled, and a car is bleeding for 5-8 hours.

Although it can be charged with night rest time, if you encounter a sudden situation, the shortcomings of pure electric vehicles will be highlighted. my country's electric vehicle charging infrastructure has prompted the Alliance to announce data. As of June 2018, the total member units in the Alliance reported 272,000 public charging piles, but this still can't meet the normal power supply needs of new energy vehicles.

The third is the after-sales of electric cars. Although the structure of the electric vehicle is relatively simple, there is a difference between the power system and the traditional fuel car, there will be some troubles in the repair. First, the lack of maintenance technicians, the second is the lack of parts.

Traditional auto repair shops can't fix electric vehicle design appliances, and if you can't buy parts or accessories, it has brought a lot of trouble to users. These are the problems that the users will feel, and there is a problem that the user has to face the problem after using the electric car for a while, that is, the attenuation of the power lithium-ion battery. The attenuation of the power lithium-ion battery is actually not new.

Do not say that people who have ride two-wheeled electric cars have giving electric vehicles to replace the battery. Even if we usually use a mobile phone, computer-based appliances, charging will also grow slower, and life is more and more Strict problems, these most of them can be attributed to the attenuation of the battery. Electric cars also escape from the power lithium-ion battery attenuation this ring.

At present, the power lithium ion battery in the car is currently used as a battery, a lithium-ion battery, and a nickel-hydrogen battery. Among them, the NiMH battery is only used in Toyota's non-plug-in mixing vehicle, which is not suitable as a separate power source; lead-acid battery is tightly applied to low-speed electric vehicles; lithium-ion batteries are the most wide electric vehicle power lithium ion battery. Lithium-ion batteries are divided into many kinds of materials in accordance with the material, and the proven is currently used for three-dimensional lithium-ion batteries and lithium iron phosphate.

We are tight to see the attenuation of the power lithium-ion battery as a lithium-ion battery as an example. From the essential origination, the lithium-ion battery has different embedded energy when an embedding reaction occurs between two electrodes, and in order to improve the optimum performance of the battery, the capacity ratio of the two host electrodes should maintain a balance value. In the lithium-cell battery, the capacity balance is expressed as the mass ratio of the positive electrode to the negative electrode, namely γ = m + / m- = ΔXc- / ΔYC +.

The theoretical coulomb capacity, Δx, Δy of the electrode, Δx, Δy refers to a chemical metering of lithium ions embedded into the negative electrode and the positive electrode, respectively. It can be seen from the above formula that the mass ratio of the two poles is relying on the number of coulomb capacity and its respective reversible lithium ions. The ideal li-ion battery system is not changed in its cycle period, and the initial capacity in each cycle is a certain value, but in fact, the situation is more complicated.

Any side reaction that can appear or consume lithium ions or electrons can cause a change in battery capacity balance, once the battery's capacity balance occurs, this change is irreversible, and can be accumulated by multiple cycles, and the battery performance occurs. Serious impact. From the actual use environment, charge and discharge cut-off voltage, discharge rate, use temperature, long-term shelving, etc.

, is also the original. First, the charge and discharge cutout voltage is shown. According to the data, the circulation life of different charging cutoffs is shortened as the charge voltage is increased, because the high charging cutoff voltage will exacerbate the occurrence of the side of the battery.

This process is actually overcharged, refers to the continuous charging of the predetermined charging termination voltage. During the rapid charging process, the current density is too large, the negative polarization, and the precipitation of lithium will be more distinct, affecting the capacity balance of the battery. Speaking of the influence of the charge of the battery on the attenuation of the battery, we can give an example.

For example, it is often used to play games, compared to those mobile phones that are usually in standby, not only is used fast, and the battery is not used earlier, and the dynamic lithium-ion battery is also the same. Battery In the process of use, in order to meet different driving conditions, different charge and discharge rates are used, the larger the charge and discharge rate, the change in the nature of the positive electrode material, and the negative surface film is thickened, so that the lithium ion diffusion is difficult, resulting in a battery capacity attenuation acceleration It may also cause battery overheat and other issues. Therefore, frequent violent driving, such as emergency acceleration or emergency reduction can accelerate the attenuation of the battery, and the temperature soft driving in the economy can effectively add battery life.

The temperature affects the battery, with the iPhone phone as an example, often at low temperatures, even if it is full of electricity, it is a lot of apple powder. Those in the power lithium-ion battery, too high temperature will make battery life and performance rapidly, and the temperature of the electrolyte will also be lowered, and there is often a shortened mileage that enters the winter electric vehicle. Situation.

In a long time in a very cold or extremely hot temperature, the attenuation speed of the power lithium-ion battery is greatly accelerated. Finally, the long-term shelving, the power lithium ion battery will enter the self-discharge state. The self-discharge of the power lithium-ion battery causes power loss, part of the reversible capacity loss, can be supplemented by charging, the other is irreversible capacity loss.

The battery is long-term shelving and performs self-discharge, and the oxide that occurs will block the micropores on the electrode material, so that lithium is embedded and detached, which increases the increasing internal resistance and the discharge efficiency, resulting in irreversible capacity loss, that is, the attenuation of the battery. The longer the idle time, the more serious the battery is damaged, so keep the battery once, you can make the battery in a healthy state. Battery attenuation is quite affected by the owner.

After all, in a pure electric car, the battery often accounts for about 30% of the vehicle cost. This means that the battery is replaced by the battery. 5,6 Wan, the stake-related relationship can be said to be very clear, most users don't want to smash such a fee.

Moreover, electric vehicles are low in the price of the second-hand car market, and it is also caused by battery attenuation. In my country, the performance of the insire during the insulting period cannot exceed 20%, otherwise it will replace the battery for the owner of the manufacturer, so how do they adhere to how to have their own warranty policy?. For example, BYD's new energy car cell is a lifelong warranty, battery 8 years 150,000 kilometers; Teng is 8 years 150,000 kilometers free, give maintenance vouchers; Beiqi new energy three-electric system 8 years 15 kilometers, the whole vehicle warranty 3 years 60,000 Kili; Geely Emgrand is 8 years 150,000 yuan in the core components of the battery; the quality insurance period of Jianghuai New Energy Automotive Core Parts is 8 years and 15 kilometers, the electricity parts are 5 years 100,000 kilometers, and the parts are 3 months 3 months 3 Thousand kilometers, the whole vehicle parts are 3 years 120,000 kilometers; Chery new energy vehicle warranty 3 years 120,000 kilometers, three-electric system 8 years 120,000 kilometers; Zomo, three-electric system warranty is 8 years 120,000 kilometers; Tesla Models Third Electricity System is an unlimited mileage.

But there is a need to say that there are currently new energy vehicles to make a warranty time and mileage provisions for the whole vehicle and key components, but not explain the conditions of battery warranty, causing consumers to purchase new energy vehicles, discovering battery declines and distribution Commercial dispute. Therefore, in battery warranty conditions, the new energy vehicle of the vehicle enterprise determines the relatively strict battery decay range and corresponding warranty measures, and the detailed conditions and frequency of battery replacement are necessary. The attenuation of the dynamic lithium-ion battery is unleaven, in addition to the manufacturer's responsibility, we also have to pay attention to our daily use, in order to extend the battery life.

For example, once a month to make a full penetration; try to consume the power to 20% before charging; quick slowness and charging; refuse to drive. Have to say, although the new energy car has been destined to become a trend, but the short board in battery technology is still hindering its development, and this is also the space of the new energy car. I believe that with the rapid progress of technology, whether it is in the endless mileage, it is difficult to charge or make the headache battery attenuation, it will be properly handled.