Lithium battery for new energy vehicle power -Lithium - Ion Battery Equipment

Breakthrough in new energy vehicle power lithium battery -Lithium - Ion Battery Equipment

Last year, the domestic car market was in a recession. There were many sad and desolate places. Many joint ventures with outstanding performance also turned from rising to falling. However, in such a bleak environment, new energy vehicles are still rising against the trend, with production and sales exceeding one million and becoming the most dazzling star in the market.

The rapid development of new energy vehicles largely benefits from the substantial improvement of power battery performance. It has been 10 years since the lithium-ion power battery was applied to electric vehicles in 2008, and the energy density of the actually installed products has increased by 2.5 times, achieving a revolutionary breakthrough in the battery field in the past century. Compared with the energy density of new energy vehicles launched in 2017 and 2018, the energy density has increased dramatically in just one year, with the average increasing from 103.3W/kg to 142.4W/kg.(Lithium - Ion Battery Equipment)

The performance improvement has driven the price of power battery down significantly. In the past ten years, the leading battery prices in Japan and South Korea have dropped from US $600-800/kWh in 2010 to US $150-200/kWh at present, and the leading domestic manufacturers have also dropped to about US $300/kWh at the end of 2016, which has now reached US $200-250/KWh. It is reported that the battery cost of BYD, a domestic battery giant, can reach 0.9 yuan/wh.

At present, most of the power batteries carried by pure electric vehicles in China's new energy vehicle market are lithium ternary materials and lithium iron phosphate materials. Although the energy density has been greatly improved compared with lead-acid and nickel metal hydride batteries, it is still difficult to dispel the anxiety of consumers about mileage. There is no doubt that the technical bottleneck of power battery has hindered the industrialization of new energy vehicles for a long time. So, can the density of lithium ion batteries be improved? Will there be a revolutionary breakthrough in the battery of new energy vehicles?

To solve this problem, we must start with the energy density of the battery. The energy density of the battery is the electric energy released by the average unit volume or mass of the battery. The greater the energy density of the battery, the more power stored in the unit volume or weight.

For electric vehicles, the energy density of the battery often points to two different concepts, one is the energy density of a single cell and the other is the energy density of the battery system. The cell is the smallest unit of a battery system. Taking Xuanyi Pure Electric as an example, 8 electric cells form a module and 24 modules form a battery pack, which is the basic structure of the vehicle power battery.

The energy density of a single cell, as the name implies, is the energy density at the level of a single cell. System energy density System energy density refers to the weight or volume of the entire battery system after the completion of monomer combination compared to the entire battery system. Because the battery system contains battery management system, thermal management system, high and low voltage circuits, etc., which occupy part of the weight and internal space of the battery system, the energy density of the battery system is lower than that of the single unit.

To improve the energy density of the power battery pack, the first is to improve the efficiency of grouping, and the second is to use cells with higher energy density. Group technology can be improved by improving the design of the battery pack and using carbon fiber light materials, but there is little room for improvement, which can only be seen as piecemeal.

Improving the energy density of single electric core is the core to solve the problem. The reason for limiting the increase of energy density of lithium battery is the chemical system behind the battery. Generally speaking, lithium battery is divided into five parts: positive and negative electrodes, electrolyte, diaphragm, and shell. The positive and negative electrodes are the main battlefield of energy storage and discharge, so most of the research and development of batteries are focused on the expansion of positive and negative electrode materials.

The energy density of the battery is controlled by the positive and negative poles of the battery. At present, the energy density of cathode materials is much higher than that of cathode materials, so to improve the energy density, it is necessary to continuously upgrade the cathode materials. For example, we all know that the energy density of the battery pack system with ternary lithium as the positive pole is higher than that of the battery pack system with lithium iron phosphate as the positive pole. 



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