Battery Lab Equipment,Lithium Battery Separator,Battery Testing Machine

According to China's goal of achieving power battery energy density of 300Wh/kg by 2020, it is inevitable that the material combination form of NCM 811/nca with silicon-carbon anode is adopted.
In the first half of this year, the application of NCM 811/NCA materials in the power battery market gradually increased. As the core equipment technology of high nickel anode materials involves upgrading and adjustment, the production process control is more strict than that of conventional anode materials, which drives the technical upgrade of material equipment manufacturers. In general, the core equipment that high nickel anode materials enterprises need to upgrade and replace mainly includes: furnace, drying equipment, crushing equipment, grinding machine, dehumidification equipment, etc.

Based on the progress of technology, China's lithium electrical equipment has been greatly enhanced in the automation level. Power battery enterprises' requirements on product performance, such as production efficiency, consistency and reliability, etc., are also gradually increasing. In the first half of this year, integrated equipment showed a trend of acceleration.
In the field of front-section equipment, it mainly includes the combination of "laser cutting machine + battery winding machine", "roller press machine + cutting machine", "battery coating machine + roller press machine + cutting machine" and other types of equipment integration.

1. The blocking current of the diaphragm plays a key role in preventing the potential safety hazard of the battery. The diaphragm is a protective band in the case of short circuit. When the diaphragm is at about 130 degrees, the resistance will increase abruptly, thus preventing the lithium ions from transferring between them. When the diaphragm is above 130 degrees, the protective band is safer.
Improper battery use (such as short circuit, overcharge, etc.) which increases the temperature of the battery may increase the resistance of the diaphragm by 2 to 3 orders of magnitude. Diaphragm requires not only at about 130 ℃ can current interrupt, and require it at a higher temperature can maintain its soften integrity. The softening integrity of the high temperature is also important for the safety of the battery under long time overcharge or long time exposure to high temperature.

The comprehensive performance of lithium battery, such as specific capacity, no memory effect, long life and environmental protection, far exceeds that of other secondary batteries. Lithium battery is called the ultimate battery, but why there is no lithium battery in the field of large-capacity battery? The key issue is the safety of lithium batteries. The biggest safety hidden danger of lithium ion battery explosion, leakage etc.

Cause:

Electric vehicles represented by Tesla compete for NCA, NCM811 or NCM622 high-nickel ternary materials as cathode materials for lithium-ion batteries. However, this high-nickel layered cathode material has safety problems, and the Canadian Light Source Energy Storage Group Dr. Zhou Wei and Dr. Wang Jian from the Chemical Imaging Line Station and Associate Professor Lu Mi from Xiamen University of Technology, for the first time, imaged the phase distribution before and after the thermal runaway of complex composite electrodes, and separated the phases before and after thermal runaway. Correlation was performed at the nanometer level and it was found that thermal runaway may be closely related to the distribution of conductive agents and binders.
Before the thermal runaway, the conductive agent and the binder are uniformly mixed in a coexisting agglomeration mode, but the agglomeration is uneven on the surface of the lithium cobaltate particles and between the particles. The thermal decomposition of PVDF is obvious after thermal runaway, while the conductive carbon black is unevenly distributed on the surface of lithium cobaltate in the form of agglomeration. PEEM can achieve a spatial resolution of 100 nm and can image a 50 um electrode surface. High spatial resolution and large imaging intervals enable high resolution imaging of multiple particles. The morphology of the lithium cobaltate particles before and after thermal runaway can be used to study the thermal runaway behavior of the same electrode particles.

With the rapid growth of the number of new energy vehicles, the power battery safety accident has become one of the key bottlenecks restricting the rapid development of new energy vehicles, and it also seriously threatens the personal safety of the occupants.
Figure 1 : Lithium polymer battery making process for cylindrical cells

Recently, the University of Maryland, the National Laboratory of the Department of Energy and the US military researchers have developed a new type of cathode nanomaterial lithium battery, which has three times the energy density of existing commercial lithium batteries. The research results were published in Natural Communication. "Journal.

With the increasing use of lithium batteries, the demand for high energy density batteries is also growing. However, in a conventional commercial lithium battery, the anode material is usually a good conductive material such as graphite, but the capacity of the cathode material is very limited. Fan Xiulin, a researcher at the University of Maryland, one of the main authors of the paper, said, "Cathode materials are the bottleneck in lithium battery research. It is very difficult to improve battery energy density based on this."

As the most widely used rechargeable battery at the moment, lithium ion batteries have a very high energy density. Tin, silicon and other non-carbon materials are expected to replace the current commercial graphite oxide powder as a new generation of anode electrode materials, significantly increasing the mass energy density of lithium-ion batteries (Whkg-1), but its huge volume expansion has severely limited its volumetric performance advantages.

The carbon cage structure constructed of carbon nanomaterials is considered to be the main means to solve the problem of large volume expansion when the non-carbon anode electrode material is intercalated with lithium; however, in the process of constructing the carbon buffer network, too many reserved spaces are often introduced, resulting in the electrode materials The density is greatly reduced, which limits the anode volume performance of lithium-ion batteries.

The coating process is an important step in the manufacturing process of the lithium battery electrode, and it is the process of transferring the electrode slurry from the liquid state to the electrode solid living substance. After the electrode slurry is prepared, it is passed through a screw pump, a filter, a screen, or the like, and is coated on the current collector after being coated via an extrusion coating head or a transfer roll. After oven drying, the liquid slurry solidifies on the surface of the current collector and has stronger adhesion.

In the oven drying process, there is no obvious anomaly on the surface, but during the rolling process after coating, it is sometimes found that after the battery electrode passes over the roller, the material drop, the leakage foil, or the pressure roller abnormally darkens. phenomenon.

Recently, according to foreign media reports, the French company NAWA Technology is developing a supercapacitor based on nanotechnology - carbon nanotubes, its biggest feature is that in the case of ensuring the performance of electric vehicle battery power, compared to lithium-ion batteries Group weight loss 30%.
Figure1: Carbon Nanotube