In times of global warming and the goal of keeping global CO2 emissions as low as possible, the field of electromobility, and therefore, the development of batteries plays an increasingly important role.
The best-known representative is the lithium-ion battery. For its production, Crystec, in cooperation with its partner manufactures from South East Asia (Korea, Japan, Taiwan, China) can offer particularly efficient systems / machines.
These machines can be produced with both manual and fully automatic loading. We will be happy to help with the purchasing of stand-alone machines or entire production lines.
For Lithium-ion-batteries, a number of different manufacturing systems are required. These are listed below:
Mixer for manufacturing batteries
The anode or cathode material is mixed with additives in the mixer. Furthermore, multilayer ceramic capacitors (MLCC) or low-temperature fired ceramics (LTCC) can be produced using this machine.
An in-line machine and stand-alone devices are available.
Coater for manufacturing batteries
Coaters, which also carry out a drying step, are used to produce the separator membrane. For coating, usually a slit-type nozzle aligned against the role is used.
Roll-Press for manufactoring batteries
The roll press also known as calendar is used for mass production of cathodes and anode material, which are the heart of battery production. When calendering, several mostly heated polished rollers are used.
Slitting & Rewinding Machine
Slitting & Rewinding machine for manufacturing batteries
This system is arranged behind the roll press or coater, if necessary. It is used to cut the resulting membrane or electrode layers to the correct size.
Notching Machine for manufacturing batteries
The so-called notching machine is an alternative to the slitting & rewinding machines for cutting the electrodes. The cutting is done using a laser based cutting method.
Stacker for battery cells
In order to achieve a higher energy density and service life, several battery cells (simplified consisting of anode, cathode and separator) are stacked in parallel.
To carry out this process step, a stacking system is required in which the stacked battery cells are fused using a lamination step, similar to a fuel cell.
As a final step, the battery cell stack is encased. Depending on the battery, the system may have to be sealed or degased.
Principle of Batteries
Batteries must be differentiated into primary and secondary battery systems. While primary systems cannot be charged, the secondary systems, also known as accumulators can be recharged using
The lithium-ion battery is usually composed of several cells connected in series or in parallel. This allows both the nominal voltage and the capacity of the battery to be adjusted.
The connection is made by welding nickel strips. The layered structure of the cell is illustrated in the following graphic:
The two electrodes form the heart of the cell. Graphite is usually used for the negative electrode, while the positive electrode is made of a lithium metal oxide.
The cell is filles by a liquid ion-conductive electrolyte in which Li ions can move freely. The two solid electrodes are separated by a semi-permeable separator membrane, which is only permeable for Li ions.
The cathode is located on an aluminum foil, while the anode is placed on a copper foil. Two different materials are necessary here, as aluminum would react with Lithium ions at the anode
and copper would corrode on the cathode.
The chemical processes differ in the selected metal oxides. These are described below using the CoO2 cell:
Cathode - positive electrode
LiyCoO2 + x Li+ + x e- → Lix+y CoO2
This equation clearly shows that there is no chemical conversion of the materials used. Only Li ions migrate.
The same applies to other lithium metal oxides.
Charge and discharge
By applying a potential during the charging process, positively charged Li ions (Li+) are released from the lithium metal oxide and migrate to the graphite anode.
While discharging, the lithium ions migrate back to the metal oxide. Electrons can flow to the positive electrode via the external circuit during this process.