Electric vehicles have lithium storage batteries which require a high energy density, long service life and high number of charge cycles, guaranteed by ternary oxide systems containing lithium requiring ternary precursors. However, successful production requires reliable and accurate metering pumps and systems.
Asia is one step ahead in fields of electric mobility and battery production. Japan and Korea are leading battery technology nations, followed by China. China is the largest manufacturer of electric bikes and is investing heavily in electric vehicles (EV). To achieve its goal of world market leadership in electric mobility, China is expanding its battery production capacity. Energy stores are being optimised and demand is increasingly being determined by longevity, greater energy density and enhanced environmental compatibility.
NCM storage materials
The most important storage materials for lithium ion batteries, which satisfy these requirements, are lithium nickel manganese cobalt oxides, or NCM for short. Various manufacturers in China have specialised in the production of the ternary precursors needed for this.Their appearance, particle size, size distribution, declared purity, beat density and many other characteristics are important to determining the properties of the sintered cathode end product.
The manufacturers needed to find reliable and accurate metering pumps and systems that were able to meet the stringent quality requirements of manufacturing ternary precursors.
Metering mixed metal liquids
Various consecutive production processes are needed for the production of ternary precursors. The individual processes require strict proportional control of the reactants. They have a major impact on the final product quality. Intelligent high-end metering pumps from ProMinent can meet these requirements and most importantly in a reproducible manner. GammaX solenoid driven metering pumps, Sigma motor driven mechanical diaphragm metering pumps and Hydro hydraulic diaphragm metering pumps, as well as peristaltic pumps, ensure the precise metering of all required substances.
Process stages
In up to 15 different process stages, they communicate with sensors and ensure exactly the right quantities at the right time thanks to the control system. For example, Sigma pumps meter all individual, soluble liquid metal mixes with nickel, cobalt and manganese elements into a solution with an accurately defined total NCM ion concentration. Impurities involving calcium and magnesium ions can be removed by metering fluoride.
Sigma pumps meter the individual nickel, cobalt and manganese solutions into the reactor and by adding exact quantities of NAOH and ammonia solutions ensure a stable hydroxide or carbonate precipitation and a constant pH. This process takes around 24 hours and afterwards the pumps very slowly reduce the pH by metering NaOH.
Product particles form. As soon as these have reached an average size of several µm, the goal is almost reached – the particles produced are sedimented and dried at a temperature of between 60 and 150 °C. After around 15-20 hours, they can be removed as the ternary precursor.
Final product quality
The accuracy of the individual processes determines the final product quality in the production of precursors for ternary cathode materials. This and high process reliability were the main arguments in persuading various manufacturers in China to use more than 300 ProMinent metering pumps: they meter NaOH, ammonia or NCM liquid metals in various process steps. And they do so in precisely the concentrations needed to produce high-quality, ternary precursors for cathodes for lithium ion batteries.
Dulcotest sensors, DACA controllers, gammaX solenoid driven metering pumps (for Lab application), and motor driven mechanical diaphragm metering pumps Sigma and hydraulic diaphragm metering pumps Hydro (for mass production application) as well as peristaltic pumps(for both lab & production phases) reliably ensure the material properties needed, such as the shape, declared purity, beat density, particle size and specific surface of the ternary precursors.
The pumps are equipped with safety and monitoring functions, including a flow control and diaphragm rupture warning system. For safe operation, back pressure and safety valves, pulsation dampers, magnetic flow meters and sensors are integrated in the metering systems. A digital control system uses parameters, such as the measured flow or pH of the Dulcotest sensors, for monitoring. and control. Depending on the control parameters present, the capacity of the individual metering pumps is adjusted accordingly using a PID controller.
