An infographic showing where batteries are positioned in an electric vehicle
9 min read

Invisible heroes of mobility transition: How pumps and valves enable sustainable mobility

 

Rechargeable batteries are decisive for the transition to an electromobility with low CO₂ emissions. What is not widely known: Pumps and valves play a key role in producing batteries for electric cars.

A bar chart showing the current and future demand for lithium-ion batteries

Demand for electric cars is rising – and so is the demand for batteries.

The future of mobility is electric: According to the International Energy Agency (IEA), electric car sales from the first quarter of 2023 to the first quarter of 2024 alone have grown by about 25 percent. For 2024, the organisation is predicting the share of EVs among newly registered cars to be 45 percent in China, 25 percent in Europe and more than 11 percent in the USA. And by 2025 this trend will have multiplied by anywhere between seven and twelve, depending on the scenario. This increase has naturally led to a higher demand for lithium-ion batteries. From 2022 to 2023, for example, it rose by 40 percent to more than 750 gigawatt hours (GWh). McKinsey estimate that the demand will increase by 27 percent per year and will reach 4700 GWh by 2040. Specialised pumps and valves contribute to a successful mobility transition.

Pumps and valves play a crucial rule in manufacturing batteries.

Producing electric car batteries requires a complex production chain distributed over the entire globe – pumps and valves are involved in almost every step of the production chain.

The production chain starts with mining raw materials such as lithium, cobalt, manganese, nickel and graphite. These are the active materials (Battery Active Materials, BAM), whose electrochemical properties allow energy to be stored. The most important of these raw materials is lithium, which is isolated and cleaned in the lithium refining step. In parallel, cathode materials are manufactured that can absorb and release lithium ions, which is required to charge and discharge the battery. At the same time, an electrolyte is produced, which is a liquid that allows lithium ions to move. The next step is that of manufacturing cathodes. In the step of assembling and filling the battery cells, cells are made out of the electrode and electrolyte materials. They can be connected in series or in parallel to reach the required voltage. Once the life cycle of the battery has come to an end, the majority of raw materials can be recycled and re-used.

How do pumps and valves contribute to battery production? The numbers in the above infographic indicate steps in which pumps and valves play a crucial role. Let’s have a look at them in more detail.

The LCC-M pump model

1. Mining raw materials: Wear-resistant slurry pumps transport abrasive brines and sludges.

First of all, raw material companies mine the battery’s active materials (Battery Active Materials, BAM): lithium, manganese, nickel, cobalt and graphite. Most of them are extracted through surface mining. At the actual mining location, the companies concentrate the raw materials for transport. They use various methods: In flotation, for example, ores are ground and mixed with water. Air is added to make the metal particles swim up to the surface as foam. Often, mining companies also gain lithium from brines. These salt-containing solutions can be found underneath dried up salt lakes in South America, for example. The companies then concentrate the brines in large tanks where the water evaporates in the hot sun. No matter if ore or brine – for mining active materials the companies require pumps that are resistant to abrasive solids and corrosive salts. The LCC-M, for instance, is a high-efficiency slurry pump with excellent wear properties. Its casing, impeller and suction cover are made of white cast iron with a high chromium content. The pump can be easily dismantled and reassembled for maintenance and inspection work. If required, KSB supplies this pump with polypropylene or butyl rubber lining.

2. Lithium refining: Hermetically sealed chemical pumps for hot and aggressive solutions

Lithium is the most important of the active materials. Lithium refineries separate it from other substances such as calcium or magnesium to make it usable for battery production. To do so, they heat up the mined and concentrated substance and mix it with sulphuric acid to extract the lithium. If the concentrate was extracted from a brine, they add soda to precipitate out lithium compounds in the form of white flakes. A different procedure is used by the company Vulcan, pumping hot brine from a depth of 3000 to 5000 metres below the Rhine Rift Valley in Germany: They use electrolysis to separate the salt in the brine into lithium and chlorine. The end products of these processes are lithium carbonate, lithium hydroxide or metallic lithium. What all these procedures have in common is that they place extremely high demands on pumps and valves because they work with corrosive, abrasive and often hot solutions. In general, plastic-lined valves and pumps are needed that are resistant to chemicals. An example of a suitable pump is KSB’s Magnochem standardised chemical pump. It uses a magnetic coupling for transmitting the torque to the shaft through the casing without any contact. As this eliminates the need for sealing elements at which leakage could occur, the pump is particularly suited for handling toxic and corrosive fluids. The pump set can handle temperatures of up to 400 °C.

The KWP pump model

3. Manufacturing the cathode material: Highest purity for optimum performance

The cathode is the most important part of a battery. It absorbs lithium ions during the charging process and releases them during discharging, enabling the current to flow. The cathode's capabilities are due to the special, crystal-forming materials they are made of: metal mixed oxides such as lithium nickel manganese cobalt oxide or lithium iron phosphate. The spaces between the crystalline structures allow lithium ions to enter and exit. An important step is the production of pre-stages of these crystalline mixed oxides, which are called precursory Cathode Active Materials (pCAM) in the industry. They play a decisive role regarding the capacity, cycling stability and safety of the battery. Pumps that control these chemical processes have to meet extremely stringent cleanliness standards, as even the smallest contamination could have a significant impact on the batteries’ performance. For instance, they must not contain substances such as lead, copper or gold as they could change the electrochemical properties of the pCAMs. This is why KSB uses special materials for manufacturing pumps for these processes, such as its KWP pump. Pumps and valves also control numerous auxiliary processes in pCAM production. The MegaCPK pump, for example, provides hot water and cooling water, and the hermetically sealed Magnochem mag-drive pump safely handles toxic substances.

4. Electrolyte production: Valves take care of accurate dosing of solvents and salts.

Lithium batteries are filled with a liquid that enables the movement of lithium ions between the two poles of the battery, i.e. the cathode and the anode. This liquid, which is called the electrolyte, is usually a solvent containing a lithium salt, such as lithium hexafluorophosphate (LiPF6). In chemical companies producing electrolytes, pumps and valves take care of transport from the storage containers to the mixing tanks. Precision is key as the contents have to be accurately dosed to ensure even and effective battery performance. Also, leakage has to be safely prevented and the devices have to be resistant to aggressive substances. Because if LiPF6 escapes, it can react with moisture and form highly toxic and aggressive hydrofluoric acid (HF). In addition, the organic solvents are flammable. Suitable pumps are the MegaCPK and the hermetically sealed Magnochem. An example of an appropriate valve is the SISTO-20 diaphragm valve lined with polytetrafluorethylene (PTFE). PTFE is resistant to strong acids, bases, solvents and oxidising agents. It also has a very low friction coefficient. This means the valves are easy to actuate, which also makes accurate dosing easier.

The Etanorm SYT pump model

5. Cathode manufacturing: Optimum heat distribution by thermal oil pumps

The cathodes are made by the battery manufacturers’ suppliers. In coating systems, aluminium foil is unrolled from large rollers, and the cathode material is coated onto the foil. The cathode foil is passed through a drying furnace at about 200 °C and then rewound onto a new roller. Such systems can be up to a hundred metres long. The enormous length is necessary to ensure sufficient drying time. Thermal oil provides for an optimum heat distribution in these large systems and is continuously recirculated by pumps. KSB’s Etanorm SYT pump, for example, is designed to reliably handle mineral and synthetic thermal oils at up to 350 °C. Finally, the battery manufacturers cut cathodes from the foil and produce the battery cells. They, too, require pumps and valves controlling the infrastructure for storing the electrolyte and transporting it to the production process. When the cells have been filled and sealed, they are charged once to optimise their electrochemical properties and detect any defects. After they have been stored between some days to some weeks, they are subjected to a quality check. And finally, they are inserted into the assembled battery, ready to go.

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