cpp – Process technology for the chemical industry 02.2020

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PLANTS, APPARATUS, COMPONENTS
Diaphragm metering pumps in use in battery production
Precise metering needed
Ternary oxide systems containing lithium guarantee a high energy density, long
service life and high number of charge cycles for lithium storage batteries. The
quality of the precursors required for this depends on the precise and synchronous
metering of various chemicals. The diaphragm metering pumps in the Gamma/ X and
Sigma X ranges from Prominent play a key role in this.
The demand for lithium batteries in the
communication, tools, automotive and
energy sectors is high. Becoming increasingly
lighter and with greater energy density,
they are replacing heavy lead or nickelcadmium
batteries in these applications.
Lithium iron phosphate batteries cannot
meet the requirements for electric mobility
and stationary storage as the new generation
of lithium batteries. Lithium-ion batteries
with special cathode materials are replacing
lithium iron phosphate batteries.
The new power packs have a long service
life with a high energy density and a large
number of charge cycles with maximum
safety. With carbon compounds containing
lithium, these properties can be put to use
as anodes and, with a ternary oxide system
containing lithium, as cathodes. Market researchers
are anticipating above-average
growth per year.
NCA compounds
Ternary precursors are being used for this.
These are predominantly manufactured by
means of reactions of nickel, cobalt and
manganese solutions through hydroxide or
carbonate precipitation. In this process, sodium
hydroxide acts as a precipitant and
ammonia as the complexing agent. For
special applications, the manganese is replaced
with aluminium solutions and receives
NCA compounds. NCM or NCA precursors
are obtained by various solutions
being combined in precisely specified quantities,
within a specific time frame, at specified
temperatures, under stable conditions,
and reacting accordingly. The reactions of
the chemicals affect the critical properties of
the precursors, such as the particle size and
their specific surface. Strict proportional
control of the reactants directly determines
the final ternary material properties and
their quality, as well as the purity of the sintered
ternary lithium, nickel, cobalt and
manganese (NCM) compounds. To obtain
an exact quality in the precursors, and
above all one that can be reproduced, smart
high-end metering pumps are increasingly
being used. These ensure the exact metering
of the individual heavy metal solutions
required for the reaction to achieve the
requisite precursor quality at all stages of
production.
Metering station with Gamma/ X solenoid-driven metering pumps and Sigma X motordriven
metering pumps. Direct input of the required final concentration in concentration
mode ensures precise volume-proportional metering.
Pictures: Prominent
Task of the metering pumps
Typical production for ternary precursors
consists of up to 15 different process stages.
Within the individual processes, solenoiddriven
metering pumps and motor-driven
metering pumps are used to precisely meter
fluoride, liquid metal solutions containing
amounts of nickel, cobalt and manganese,
plus sodium hydroxide (NaOH) and ammonia.
In the key process step, the synthesis
reaction, ultra-pure water and ammonia are
added as the base fluid. Depending on the
pH value, three diaphragm metering
pumps, for example, synchronously meter
the various liquid metal solutions at around
48 cpp 02-2020