The world’s bitter battery innovation has been long gone. In the history of hybrid and pure electric vehicles, lithium iron phosphate batteries were once considered by manufacturers to be the most reliable choice. But now in the family new energy vehicles, the term is almost no longer mentioned. The reason is that another technological route is gaining the upper hand, namely the three-dollar lithium-ion battery that people now hear the most.
“The industry is too dependent on the triple lithium battery, leading consumers to put a question mark on the safety of new energy vehicles. Byding’s chairman and president, Wang Chuanfu, said.
This time, BYD took a step forward in battery innovation by launching a “blade battery” in response to the pain in the field of in-car power batteries.
What is a blade battery? In general, the battery pack of an electric vehicle consists of a module consisting of multiple cells. The cell, for example, is a cylindrical 18650 battery. In order to keep the core module stable in the vehicle, it is necessary to secure it with bolts, beams, vertical beams, etc. The blade battery is different in that it eliminates the module and directly loads the cell into the battery pack in an array way, which in turn increases internal space utilization.
Blade Battery Structure Diagram . . . Byd
More innovative than the structure is that the blade battery is bringing people’s eyes back to the lithium iron phosphate battery that is already forgotten by home electric vehicles.
In the field of new energy passenger cars, the three-dollar lithium battery is almost “all over the world”. According to statistics from the Research Department of the Power Battery Application Branch, the installed capacity of the three-dollar lithium battery and the lithium iron phosphate battery in the first half of 2019 was 71.14% and 26.97%, respectively, and the gap continued to widen compared to the same period in 2018.
2018 and 2019 New Energy Vehicle Power Battery Installed . . . Power Battery Application Sei
But that doesn’t mean the triple lithium battery is the only option. If you lengthe the timeline, you’ll find that there are no so-called “winners” in the battery’s technical route.
Battery technology is to some extent leading the development of electric vehicles. Electric vehicles developed rapidly at the end of the 19th century. People use electric cars for the same reasons as they do today: no noise, no smell, low prices.
From the end of the 19th century to the beginning of the 20th century, the car market even created a “three-way” situation: steam, electric steam and internal combustion engines. But with the internal combustion engine growing fastest, the other two eventually pulled out of the car market.
Due to the environmental pollution of the atmosphere and the rise of battery technology, electric vehicles have been paid new attention. The early electric car market presented a “hundreds of contentions” state, all kinds of battery technology are equipped with the car.
In 1990, GM first demonstrated the Impact electric concept car at the Los Angeles Auto Show, with a huge industry impact. GM then developed the all-electric sedan EV1 based on Impact’s core technology and design, which is seen as the driving rock for modern electric vehicles.
General Motors Impact Electric Concept Cars Wikipedia
With this, major auto manufacturers have invested a lot of resources in developing electric vehicles, the only difference is that the internal batteries of the vehicle are not uniform. The EV1 is equipped with lead-acid batteries, the Ecostar with calcium-sulfur batteries was introduced by Ford in 1992, the RAV4LEV, toyota’s hybrid vehicle with nickel-hydrogen batteries, and the 1997 Toyota-hybrid Prius (also equipped with a nickel-hydrogen battery), Nissan also launched the world’s first lithium-ion battery electric car, the Prairie Joy EV, in the same year…
The speed of commercialization is one of the most important factors in the development of testtechnology. Since Sony commercialized lithium-ion batteries in 1992, it has coincided with the development of the telecommunications and information markets, as lithium-ion batteries have become the best choice for electric vehicles in terms of commercial advances due to the highest volume-to-energy-to-mass ratio. Among them, the most representative is the iron phosphate lithium battery and the three-way lithium battery.
The battle over the technical route
After the rise of lithium-ion batteries, can be used as a new energy vehicle power battery, there are only three types can be qualified: iron phosphate lithium battery, three-yuan lithium battery and lithium titanium acid lithium battery. The last of these is that the number of people in general is too small to be discussed for the time being.
Iron phosphate lithium battery uses lithium phosphate as a positive material, while the positive material of the teratonia lithium battery uses lithium nickel cobalt manganese acid, and the negative material is graphite. A few key points are briefly listed for the advantages and disadvantages of the two:
In terms of cost, the cost of lithium iron phosphate is much lower than the cost of a three-dollar lithium battery. The former is characterized by the non-precious metal elements, so the cost of raw materials can be relatively compressed to very low, while the cobalt element in the triple lithium battery belongs to the precious metal element, and the price of cobalt is rising rapidly, with the rise of 5G and other emerging things, the gap between supply and demand of cobalt will further widen.
In terms of energy density, iron phosphate lithium batteries are far less powerful than teracan lithium batteries. The weight energy density of lithium iron phosphate batteries alone is only 120Wh/kg, and if the energy density of the entire reactor, including battery management systems, cooling and other components, is calculated, the energy density of the triums lithium battery can reach 200Wh/kg.
In terms of safety, lithium iron phosphate batteries are even better. The chemical properties of lithium phosphate are stable, high temperature stability is good, 700 degrees C-800 degrees C will occur decomposition, and in the face of impact, needle, short circuit and other conditions will not produce violent combustion, high safety performance; The carbon material then burns, generating heat that further exacerbates the positive decomposition and explodes in a very short time.
In recent years, the self-ignition of new energy vehicles, most of them are caused by the three-dollar lithium battery. The reason why no major accidents occurred is that the vehicle’s battery management system is relatively good, for vehicles equipped with three-way lithium battery, battery management system and cooling system design are critical.
Based on safety considerations, new energy buses carrying three-way lithium batteries can not enter the Ministry of Industry and Information Technology’s new energy vehicle catalog, but China’s policy on new energy vehicles at the same time has strict regulations on energy density, three-way lithium battery has become the mainstream choice of new energy passenger cars.
In the service life, iron phosphate lithium battery in the circulation utilization rate than the three-dollar lithium battery has more advantages, but the low temperature performance of iron phosphate lithium battery is poor, which is its “fatal injury”. Studies have shown that at low temperatures (temperatures below -10 degrees C), lithium phosphate batteries go through less than 100 charge and discharge cycles, reducing the battery capacity to 20% of the initial capacity. The low temperature performance of the three-way lithium battery is excellent, and the normal battery capacity can be maintained under the condition of -30 degrees C, and it is obvious that lithium iron phosphate can not meet the standard of use in the low temperature area of northern China.
In summary, the three-way lithium battery relies on high energy density to successfully “upper”, and the direct performance of energy density is a high range, you can see that the current several electric vehicles range has exceeded 700km, which is the car companies and consumers pain point, so the three-way lithium battery has become the mainstream choice of electric vehicle enterprises. And iron phosphate lithium battery temporarily flagging, because of high safety has become the first choice of new energy passenger cars.
But when we analyze the advantages and disadvantages of the two types of batteries in detail, we will find that if the energy density of lithium iron phosphate increases, the current market for three-way lithium batteries will probably be a big shock. This is also an important reason for the widespread discussion of blade batteries.
Can the blade battery “break out”?
According to BYD, the blade battery volume energy density and the mainstream triple lithium battery, in the same volume of storage of electricity is similar.
As stated at the beginning of the article, the blade battery eliminates the module steps compared to the traditional battery pack, using the CTP (Cell to Pack, no module power battery pack) design idea, the cell is installed directly into the battery pack housing. This design eliminates accessories such as beams, girders and bolts while maintaining the strength of the battery pack, increasing the internal space utilization of the battery pack and increasing the total capacity and energy density of the battery pack.
It is reported that BYD through the CTP design to increase the space utilization rate inside the battery pack housing from the traditional design method of 40-50% to 60-80%. The increase in the total capacity of the battery pack is a direct result of a significant increase in the battery life of electric vehicles. Blade battery was the first BYD “Han” model, the range reached 605km, basically reached the same level as the three-way lithium battery model.
But in terms of safety, the blade battery performs much better.
BYD Battery Lab conducted a needle test on lithium iron phosphate batteries, blade batteries and terayuan lithium batteries, using steel needles to pierce the battery substrate, instantly triggering a short circuit inside the battery, causing the battery to get out of control.
The needle test is recognized as the harshest of all battery safety tests and simulates a short circuit in an extreme battery condition. In the mass consumption of digital products such as mobile phones, laptop batteries are a mandatory project, in new energy vehicles are not used as mandatory standards.
According to the three battery sample needle test video, NCM622 (the ratio of nickel cobalt manganese in positive material is 6:2:2) three-way lithium battery burst struck the moment the needle pierced, compared to the iron phosphate lithium battery is slightly safer, in the moment of puncture, the moment the needle punctured, Lithium phosphate did not catch fire, but the temperature on the surface of the battery was as high as five or six hundred degrees Celsius.
The blade battery is not abnormally well-behaved when it is punctured, and the structure remains stable. The temperature sensor shows that the temperature on the surface of the battery is only 60 degrees Celsius, safely through the needle test.
Three battery needle test results BYD Battery Lab
Battery safety is indeed one of the top concerns for consumers, and the blade battery solution reinforces this and gives lithium phosphate batteries some say. It is also understood that Tesla and The Ninder era are in talks, the Chinese-made Tesla cars will use the latter’s non-cobalt battery, the probability is iron phosphate lithium battery.
Tesla CEO Elon Musk said in June 2018 that he was working to reduce the amount of cobalt used by Tesla, which uses about 3 percent of the cobalt used in batteries to get it out of the raw material list in the next generation.
Can lithium iron phosphate battery surpass the three-way lithium battery and become the mainstream of automotive power battery again? Before the results, no one could say well. But innovation in the field of batteries, the development of a cost-effective battery, is indeed the focus of all enterprises today.
Blade battery opened a head, in the car power battery innovation toward the bottleneck period, the range of up “climbing” speed is getting slower and slower, the blade battery back to the near-forgotten type of battery on the stage. If widely used later, it might give mainstream car companies another option at the crossroads of power batteries.