32 January/February 2025 | E-Mobility Engineering There are three major phases of activity for manufacturing battery cells, as Nick Flaherty reports Building blocks Moving from small coin cells that prove the performance of a battery chemistry in the laboratory to production is a big step. There are many different ways to construct a cell, and many techniques for both building and characterising the resulting battery. The process of creating A, B and C samples of battery cells is key for continuous improvement to enhance the quality of cells, whether in a cylindrical, pouch or prismatic form factor. With new battery chemistries emerging and new approaches for building cells, particularly using solid-state materials, the process of battery manufacturing is a key area for e-mobility. High production volumes in battery gigafactories are generally associated with economies of scale, and these are increasingly requiring highly digitalised and automated unique procedures that seek to combine various routes and complex sub-processes. The manufacture of safe, reliable batteries for e-mobility depends on this. There are three major phases or blocks of activity for manufacturing battery cells: electrode manufacturing, cell assembly and validation. Production process Whatever the format (pouch, cylindrical or prismatic), the first step in manufacturing a battery is to produce the two covered layers known as electrodes. At this stage, it is vital to avoid contamination between materials, which is why gigafactories have two identical and separated production lines: one for the anode and the other for the cathode. Generally, the anode is made of copper foil, coated with graphite. The cathode is composed of an aluminium foil, coated with a chosen chemistry; nickel manganese and cobalt for NMC cells, nickel cobalt for NCA cells or iron phosphate for LFP cells. Four stages There are four stages in the electrodemanufacturing process, as follows. Mixing In the electrode production process, the first step is to produce a mix known as slurry, which has a significant impact on the battery’s final performance. This procedure is key for the subsequent bonding of the active material to the current collector, which will then transfer the electrochemical energy through the cell tabs. The slurry is a mixture of powders (mainly active material) combined with a solvent (liquid) and a binder. Solid state battery manufacturing (Image courtesy of Honda Motors)
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