What's the difference between a ternary battery and a lithium battery?

The ternary polymer lithium battery refers to a lithium battery using a nickel-cobalt-manganese hydride (Li (NiCoMn) O2) ternary positive electrode material for the positive electrode material, and a ternary composite positive electrode material precursor product, which is a nickel salt, a cobalt salt, and a manganese salt. As raw materials, the ratio of nickel-cobalt-manganese can be adjusted according to actual needs.

The ternary lithium battery is characterized by high energy density and higher voltage, so the battery pack with the same weight has a larger capacity, the car runs farther and the speed can be faster. However, the weakness is that the stability is poor. If there is an internal short circuit or the positive electrode material is in contact with water, an open flame will occur. Therefore, the general 18650 battery will have a layer of steel shell protection. Since Tesla's battery pack is composed of 7000 or so 18650 batteries, Tesla provides a full range of protection for the battery pack, but in extreme In the event of a collision, there is still a fire hazard.

The reason for this is that the two materials decompose when they reach a certain temperature, the ternary lithium material will decompose at a lower temperature of about 200 degrees, and the lithium iron phosphate material is at about 800 degrees. Moreover, the chemical reaction of the ternary lithium material is more intense, and oxygen molecules are released, and the electrolyte rapidly burns under the action of high temperature, and a chain reaction occurs. To put it simply, the ternary lithium material is more likely to catch fire than the lithium iron phosphate material. However, it should be noted that we are referring to materials, not batteries that have become finished products.

lithium iron phosphate battery should be much more stable. The battery board will not explode and burn even if it is puncture or short circuit. It will not catch fire when it is heated at 350 °C (the ternary lithium battery can't stand at 180-250 °C). Therefore, in terms of safety performance, lithium iron phosphate battery is slightly better.

Because ternary lithium materials have such safety hazards, manufacturers are also trying to stop the direction of accidents. According to the easy pyrolysis characteristics of ternary lithium materials, manufacturers will have a lot of problems in over-charge protection (OVP), over-discharge protection (UVP), over-temperature protection (OTP), and over-current protection (OCP). effort. Tesla is confident in safety because it has a complete battery management system that manages the more active ternary lithium battery. Of course, with more and more battery companies, car companies and professional battery management companies in this field of research and development, more companies can also achieve excellent battery management, greatly improving safety.

Energy density is the core element

Energy density refers to the amount of energy stored in a given space or mass of matter. The energy density of a battery is also the amount of energy released by the average unit volume or mass of the battery. Battery energy density = battery capacity × discharge platform / battery thickness / battery width / battery length, the basic unit is Wh / kg (Wh / kg). The greater the energy density of the battery, the more electricity is stored per unit volume.

Here, it must be said that the guiding principle of the national policy for the industry is also very clear. On March 1, 2017, the four central ministries and commissions issued a notice on the “Action Plan for Promoting the Development of Automotive power battery Industry”, clearly stating “will improve battery specific energy as one of the key development goals in the future”.

The following three points focus on:

1. By 2020, the specific energy of lithium-ion power battery cells is greater than 300Wh/kg; the system specific energy is expected to reach 260Wh/kg; the cost is less than 1 yuan/watt hour; the use environment is -30 °C to 55 °C; with 3C charging capacity.

2. By 2025, the monomer specific energy reaches 500Wh/kg.

3. Strive to realize the industrialization and vehicle application of lithium-ion battery products with single cell 350Wh/kg and system 260Wh/kg.

Ternary refers to the name of the positive electrode material inside the lithium battery. The ternary material is lithium nickel cobalt manganese oxide Li (NiCoMn)O?, a ternary composite positive electrode material precursor product, which is made of nickel salt, cobalt salt and manganese salt. The ratio of nickel cobalt to manganese can be adjusted according to actual needs. 18650 refers to the cylindrical battery appearance size: 18 refers to the battery diameter of 18.0mm650 refers to the battery height of 65.0mm, used in mobile phones. Lithium batteries are more versatile, and most of the batteries on the market are not detailed here.

Ternary refers to the name of the positive electrode material inside the lithium battery. The conventional battery positive electrode material is lithium cobaltate LiCoO2, and the ternary material is lithium nickel cobalt manganese oxide Li (NiCoMn)O2, a ternary composite positive electrode material precursor product, which is made of nickel salt, cobalt salt and manganese salt. The ratio of nickel-cobalt-manganese can be adjusted according to actual needs. The battery with ternary material as positive electrode is safer than lithium cobalt oxide battery , but the platform is too low, which is used on mobile phones (the cut-off voltage of mobile phone is generally around 3.4V). The feeling of insufficient capacity of 18650 refers to the cylindrical battery exterior dimensions: 18 refers to the battery diameter of 18.0mm650 refers to the battery height of 65.0mm. Other cathode materials use more than three yuan, there are lithium cobaltate, lithium manganite, lithium iron phosphate, NCA and so on.

Lithium batteries refer to a very wide range of types. Anyone who uses lithium materials can be called a lithium battery. According to the scientific name, the lithium battery we usually say should be called lithium ion battery / lithium secondary battery, with corresponding anode material.

The positive electrode materials of lithium ion batteries mainly include lithium cobaltate LiCoO2, lithium manganite LiMn2O4, lithium nickelate LiCoxNiyMnzO2, ternary materials, lithium iron phosphate LiFePO4 and the like. The positive electrode uses a ternary material called a ternary lithium battery;

The main advantage of the ternary lithium battery is that the energy density is higher than other materials;

The positive electrode material of the ternary lithium battery is further divided into NCA nickel cobalt aluminum and NCM nickel cobalt manganese;

Most of the ternary materials are NCM. Generally speaking, the ternary lithium battery refers to NCM. NCM foreign representative manufacturers are SDI and SKI. In China, they are mainly Lishen, Huitong Tianxia, BAK, Wanxiang and Delangeng. Tesla adopts NCA18650 type, NCA has relatively strong stability and strong cycle performance; however, in the production process, since Al is an amphoteric metal, it is not easy to precipitate, so there is a threshold in the process. Since the content of aluminum in NCA is too small, it is also often referred to as a binary material.

The ternary material NCM product model ranged from 111 ternary (N:C:M=1:1:1) to 433,532,622,811. As the nickel content increases, the battery energy density is correspondingly increased.

The name of the ternary lithium battery is very loud, but the specific content is probably not clear to many friends, so you need to pay attention. The ternary positive electrode material has advantages in terms of battery specific energy, specific power, large rate charging, low temperature performance, etc., in terms of cycle performance, lithium iron phosphate is better, but it becomes worse in a cold environment. In terms of safety, lithium iron phosphate is originally the most ideal, but the reinforced three-element lithium battery management technology has gradually improved.

From this we understand that in the field of commercial vehicles, such as bus, the space is large, the specific energy and specific power requirements of the battery are relatively low, and the lithium iron phosphate battery can be selected to exert its cycle performance. While the space of the car is limited and the amount of the battery is small, it is more suitable to use a high specific energy and a high specific power ternary material battery. From the perspective of adaptation policy, the future energy density requirements are higher, and the potential of the ternary lithium battery will be more exerted.