Test background

In the production process of lithium anode and cathode materials, conductive agents and electrolytes, magnetic substances are introduced due to mechanical equipment wear in processing, storage, transportation, packaging and other links as well as poor control of raw materials. These magnetic substances are of great harm to lithium batteries. When magnetic foreign bodies (Fe, Cr, Ni, Zn and other elements or alloys or oxides) appear in the materials, Can cause battery internal short circuit, mainly divided into physical short circuit and chemical short circuit.

Physical short circuit: large metal particles in the positive electrode material can directly Pierce the diaphragm, resulting in short circuit between the positive and negative electrodes, which can be detected in the production process of lithium electricity.

Chemical short circuit: After the positive material is prepared into a battery, when the voltage reaches the REDOX potential of these foreign bodies in the charging stage, it will be oxidized in the positive electrode and then reduced in the negative electrode. Metal precipitation, continuous deposition and accumulation, when the accumulation of metal elements in the negative electrode to a certain extent, sharp metal edges will Pierce the diaphragm, micro short circuit, self-discharge. After puncturing the diaphragm, the resulting self-discharge rate is accelerated. In this process, the electrolyte gradually produces the release of HF, which will oxidize the elemental metal to form stable MF, even MF·3H2O, and finally form a raised SEI film that directly contacts the positive and negative electrodes due to its poor electronic conductivity. Eventually, the battery may burn and explode, resulting in safety accidents. Such abnormal batteries can only be detected after several cycles of charging and discharging.

In fact, the magnetic material under the action of the external magnetic field shows a strong magnetization effect, so the magnetic field can be arranged by the way of the powder or slurry in the trace and trace magnetic material magnetization, and through the magnetic absorption effect, the magnetic material is separated.

Applicable standard

MS series magnetic material separator is based on GB/T37167-2018 "Separation and determination of trace and trace magnetic substances in inorganic powder" and SJ/T 11795-2022 "Lithium ion battery electrode material magnetic foreign matter content test" standards, optimize including mixing, sorting, cleaning, recovery and other operational processes, The patented mean-field eddy current three-stage magnetic suction device was used to efficiently capture the magnetic material particles in the slurry.

Applicable method

It can be used as a sample pretreatment workstation for the determination of the content of magnetic metal foreign bodies by inductively coupled plasma emission spectrometry (ICP-OES), the determination of the morphology and number of magnetic metal foreign bodies by scanning electron microscopy and energy spectrometer, and the determination of the size of magnetic metal foreign bodies by cleanliness analysis.

Product feature

• Fully automatic design, minimize the influence of human factors

• The whole process design, without personnel without complicated operation, reduce the workload of personnel operation by 80%

• Innovative three-stage eddy current average magnetic suction design, slurry will 100% flow through the magnetic field

• The whole pipeline adopts non-metal, corrosion resistant design, no own pollution, not afraid of complex acid and alkali liquid system

• Standard capacity up to 1000ml, suitable for different materials

• Double motor design and control are adopted for sample mixing and circulation to ensure uniform delivery of high concentration, high viscosity and high density samples

• High efficiency non-contact ultrasonic dispersion unit with adjustable power ensures uniform dispersion of samples and full separation of magnetic material particles from material particles

• Pressure level sensing and continuous level control technology

• Standard Operating Process (SOP) control, multi SOP setup and call

• High aging ratio, the current method only takes 10 minutes, compared to more than two hours of traditional methods

Technical parameter

• Executive standards: GB/T37167-2018 "Separation and Determination of Trace and Trace Magnetic Substances in Inorganic Powder" and SJ/T 11795-2022 "Determination of Magnetic foreign bodies in Lithium ion battery electrode Materials"

• Applicable methods: ICP-OES method, electron microscope + energy spectrum method, cleanliness test method

• Applicable concentration range: 10-5000μg/kg

• Particle test range: > 0.5μm

• Sample test quantity: ≤200g

• Magnetic foreign body separation speed: 10L/min

• Sample pool material: toughened glass

• Pipeline material: PTFE

• Ultrasonic power: 0-100W continuously adjustable

• Mixing speed: 0-1000r/min adjustable continuously

• SOP setting: 10 Sops are set at the same time

• Magnetic level: three eddy current average field