Lithium battery-material-diaphragm technology route and development

Lithium-ion batteries are mainly composed of five parts: positive electrode material, negative electrode material, diaphragm, electrolyte and packaging material. The lithium-ion battery diaphragm is a porous film with uniformly distributed micropores. It is located between the positive electrode material and the negative electrode material of lithium battery. It plays a role in preventing direct contact between positive and negative electrodes, preventing battery short circuit and transmitting ions. It is a key material to ensure battery safety and affect battery performance. Although the diaphragm does not directly participate in the electrochemical reaction of the battery, its performance affects the interface structure, internal resistance and other properties of the battery, and thus affects the battery's energy density, cycle life and rate performance; the thermal stability of the diaphragm also determines the battery's operating temperature tolerance range and battery safety. An ideal battery diaphragm should have good insulation, mechanical strength, electrochemical stability and thermal stability, as well as high porosity and appropriate pore size, and good wettability and adsorption properties for the electrolyte.

▲Lithium-ion battery (cylindrical) structure and lithium battery diaphragm

Summary of high performance resin materials used in diaphragms!

The diaphragm plays two main roles in lithium-ion batteries. First, the diaphragm material needs to have good insulation and a certain strength to avoid direct contact between the positive and negative electrodes in the battery, and can effectively prevent short circuits caused by punctures such as burrs and dendrites, and ensure that there is no significant dimensional change under sudden high temperature conditions, thereby ensuring the safety of the battery. Second, the porous structure of the diaphragm can provide a good migration channel for lithium ions, ensuring stable and efficient operation of the battery.

Brief introduction to lithium battery diaphragms

In the structure of lithium batteries, battery separator refers to a layer of separator material between the positive and negative electrodes of the battery. It is a very critical part of the battery and has a direct impact on the safety and cost of the battery. Its main function is to isolate the positive and negative electrodes and prevent the electrons in the battery from passing freely, so that the ions in the electrolyte can pass freely between the positive and negative electrodes. The performance of the separator determines the interface structure and internal resistance of the battery, which directly affects the battery's capacity, cycle and safety performance. According to the differences in physical and chemical properties, lithium-ion battery separators can be divided into several categories: woven membranes, non-woven membranes (non-woven fabrics), microporous membranes, composite membranes, separator paper, rolled membranes, etc. Although there are many types, the main commercial lithium-ion battery separator materials are polyethylene and polypropylene microporous membranes. Polyolefin materials have excellent mechanical properties, chemical stability and relatively low prices. Therefore, polyolefin microporous membranes such as polyethylene and polypropylene have been used as lithium-ion battery separators in the early stages of lithium-ion battery research and development.

One of the ten key equipment for lithium batteries: Double Planetary Mixer pulping equipment

The mainstream mixing equipment used by lithium-ion battery manufacturing companies is the Double Planetary Mixer. The Double Planetary Mixer used in the lithium battery industry, also known as the PD Mixer, is equipped with low-speed stirring components (Planet) and high-speed dispersing components (Disper). The low-speed stirring components consist of two curved frame-type stirring blades, driven by planetary gears. As the blades revolve, they also rotate on their own axis, causing the material to move both vertically and horizontally, achieving the desired mixing effect in a short time. The high-speed dispersing components typically consist of toothed dispersing discs, which revolve in sync with the planetary frame, while also rotating at high speed. This creates intense shear and dispersion forces on the material, making it several times more effective than ordinary mixers. The dispersing components can be configured with either a single dispersing shaft or double dispersing shafts.

Adjustable film coater

Adjustable film coater is a film coater with adjustable coating thickness. By adjusting the two differentiators above the film coater, the scraper below can be adjusted up and down to control the coating gap and ultimately achieve the desired coating thickness.

Due to the use of a high-precision micrometer, the coating range is adjustable from 0 to 3500μm, and the gap of the scraper is adjusted in units of 10 microns during scraping.

This film applicator is ideal for research projects where even the smallest differences in film thickness need to be accurately evaluated.

The basic configuration of button batteries: Small Hydraulic Button Cell Sealing Machine

1. Vacuum mixer

SFM-7

It is used for stirring and shaking materials; it has high vacuum degree, strong stirring force and adjustable vibration amplitude. It is a dual-purpose machine with great value for money.

 

2. Digital Rotational Viscometer

SNB-2-H

A new digital product developed based on single-chip microprocessor technology and used to measure the viscous resistance and absolute viscosity of liquids.

 

3. Automatic coating and drying machine

MSK-AFA-III

Applicable to various high-temperature coating research. Ceramic thin films, crystal thin films, battery material thin films, special nano thin films. This product is equipped with a heating and drying system, and the materials are dried synchronously.

 

4. 52L vacuum drying oven

DZF-6050

Suitable for heating and drying items under vacuum conditions. Accurate temperature control, high precision; temperature control range from room temperature to 250 degrees; volume 52 liters.

A new generation of lithium-ion battery negative electrode material - silicon dioxide!

Due to the rapid development of lithium-ion batteries, people's daily life and production methods have undergone tremendous changes. At present, lithium-ion batteries are needed in everything from laptops, tablets, cameras, mobile phones to new energy vehicles, and lithium-ion battery products have spread to every corner of people's lives.