lithium battery 18650 3.7v.Interpretation of CATL’s latest patented technology for lithium-ion batteries

Against the background of the gradual launch of the energy storage market, CATL continues to strengthen research and development, continuously improve product performance, and complete the development of battery cells and corresponding system platform products that adopt low lithium consumption technology and long battery cycle life. In addition, CATL is preparing to build a 21C innovation laboratory that will benchmark against world-class standards.

Against the background of the gradual launch of the energy storage market, CATL continues to strengthen research and development, continuously improve product performance, and complete the development of battery cells and corresponding system platform products that adopt low lithium consumption technology and long battery cycle life.


In addition, CATL is preparing to build a world-class 21C innovation laboratory that will further extend from next-generation energy storage material chemical systems such as metal lithium-ion batteries and all-solid-state batteries to more future new energy applications.


CATL's technical layout of power lithium-ion batteries, energy storage and future energy fields can also be glimpsed from the patents.


On March 26, CATL disclosed three "secondary battery" related patents, involving energy storage device technology, energy storage material technology, and battery technology.
Low temperature lithium iron phosphate battery 3.2V 20A -20℃ charging, -40℃ 3C discharge capacity ≥70%

Charging temperature: -20~45℃ -Discharge temperature: -40~+55℃ -40℃ Support maximum discharge rate: 3C -40℃ 3C discharge capacity retention rate ≥70%
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3 major properties: high energy density + long cycle + high storage


In CATL's patent "Secondary Batteries and Battery Modules, Battery Packs and Devices Containing the Secondary Batteries", the devices include mobile equipment, electric vehicles, electric trains, satellites, ships or energy storage systems.


The inventor of the patent found through extensive research that when selecting specific types of positive and negative active materials, while controlling the performance parameter K of the battery within a given range (1.05 ≤ K ≤ 1.25), the battery can achieve higher energy density. down, while taking into account longer cycle life and better storage performance.


The positive active material includes one or more of lithium nickel cobalt manganese oxide and lithium nickel cobalt aluminum oxide; the negative active material includes silicon-based materials and carbon materials.


When the secondary battery meets the condition K ≥ 1.05, the number of lithium ions that can be extracted from the negative electrode plate is greater than the number of vacancies that can be embedded in the positive electrode plate.
Low temperature and high energy density 18650 3350mAh-40℃ 0.5C discharge capacity ≥60%

Charging temperature: 0~45℃ Discharge temperature: -40~+55℃ Specific energy: 240Wh/kg -40℃ Discharge capacity retention rate: 0.5C Discharge capacity ≥ 60%
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As a result, the reversible capacity of the positive electrode piece can be fully exerted, allowing the secondary battery to have a higher energy density. At the same time, the more lithium ions in the negative electrode can be used as an effective supplement for the lithium ions consumed during storage and circulation, thus greatly extending the cycle life and storage life of the secondary battery.


When K ≤ 1.25, under the same positive electrode plate design, the coating weight of the negative electrode plate is appropriate, so that the negative electrode plate has higher lithium ion conductivity and electronic conductivity, so that the secondary battery has higher Dynamic performance, it has high fast charging capability.


Negative electrode additive: Coulombic efficiency and cycle performance of the battery are greatly improved for the first time


In CATL's patent "A negative electrode additive, secondary battery, battery module, battery pack and device", the device includes mobile equipment, electric vehicles, electric trains, satellites, ships and energy storage systems.


The negative electrode additive supplied by this patent includes: a core material and a composite protective layer covering the outer surface of the core material. The negative electrode additive can be added to the negative electrode diaphragm of the secondary battery as a lithium source to compensate for the lithium consumption of the negative electrode of the secondary battery during the first charge and discharge process.


In the experiment, the battery was subjected to a cycle test at 25°C. It was charged with a current of 1C to 4.2V, then charged with a constant voltage to 0.05C, and then discharged with a current of 1C to 2.8V. This cycle of charge and discharge continued until the last discharge capacity decayed to the 80% of primary discharge capacity.


It can be seen from the execution examples 1-16 and the comparative examples that when the negative electrode of the secondary battery uses this additive, it can replenish the lithium ions consumed by the negative electrode SEI film formation, effectively improve the first Coulombic efficiency of the secondary battery, and reduce the irreversible capacity. losses, significantly improving cycle life.


Battery additives: no smoke, no fire, no explosion


In CATL's patent "A battery additive, secondary battery, battery module, battery pack and device", the device includes pure electric vehicles, hybrid electric vehicles, plug-in hybrid electric vehicles, electric bicycles, and electric pedals cars, electric golf carts, electric trucks, electric ships and energy storage systems.


The battery additive includes a core structure and a coating layer covering the core structure, and the melting point of the coating layer is in the range of 80-150°C.


When the battery is used in a high-temperature environment, the coating layer on the surface of the additive melts first, and then releases the core structure into the electrolyte, causing a micro short circuit inside the battery. This can effectively reduce the remaining power (SOC) of the battery in a short period of time. This ensures that the battery will not undergo thermal runaway at high temperatures and ensures the safety performance of the battery.


The experimental conditions are to charge the battery to 4.2V at 25°C with a constant current of 1C and a constant voltage of 4.2V until the current is 0.5C, so that it is fully charged at 4.2V. Then the battery is placed in a high temperature box and charged at 2°C/min. Rise to 120°C and hold for 4 hours. At the same time, measure the voltage change of the battery in the high-temperature box and the battery surface temperature, and observe the state of the battery after the test.


The criteria for passing this test are: the battery has no smoke, no fire, and no explosion. Finally, it can be seen from Execution Examples 1-16 that using the patented additive with a coating layer can effectively improve the safety performance of the battery.