Equans: Unparalleled Expertise!
Equans: Unparalleled Expertise!
At the Heart of the Infinitely Small
Battery manufacturing requires constant vigilance in three areas: safety, to prevent any risk of explosion or fire, humidity control, to prevent component degradation, and temperature control, to ensure the process parameters for the formation and aging stage (the battery’s first charge) and to limit the rise in temperatures within the facilities caused by the thermal loads generated by the process equipment.
The battery stores electrical energy in chemical form. Inside each cell, electrons flow between a negative electrode, the anode (copper impregnated with graphite), and a positive electrode, the cathode (aluminum impregnated with nickel, cobalt, and manganese), in a conductive liquid containing lithium salts, called an electrolyte. Lithium-ion batteries differ from traditional batteries in that they charge faster, have a longer lifespan, and offer higher energy density, resulting in greater range.
COMPONENTS OF A LITHIUM-ION BATTERY
Working in an anhydrous cleanroom
The production of electric vehicle batteries involves the handling of highly hazardous and explosive materials, particularly during the preparation of powders, the cathode drying process involving the evaporation of NMP, and the dispensing of electrolyte.
To manufacture batteries safely and with maximum efficiency, a clean and dry room is required. HVAC (heating, ventilation, air conditioning, and air treatment) systems help maintain a very low relative humidity (RH* below 2%, referred to as a “dew point” between -30 and -45°C), to prevent water from coming into contact with lithium, a highly sensitive metal.
Each room is equipped with pressure sensors to ensure that air flows from the room to the outside and never the other way around, as well as temperature and humidity sensors. The atmosphere is thus constantly monitored in a room featuring excellent airtightness and an efficient, properly sized ventilation system.
Optimized Solutions
To ensure a high-performance, secure environment for battery production, Equans designs and builds anhydrous cleanrooms that meet the most stringent standards.
Protected by an airtight enclosure, they are under continuous monitoring and feature a specialized air filtration system. This keeps humidity levels under control through uniform air circulation throughout the room and by managing positive pressure relative to adjacent rooms.
As Alex Authier, Design Project Manager in the Development Department at Equans France, points out: “Filtration, just like removing humidity, are very energy-intensive processes. Anhydrous rooms account for between 20 and 30% of a gigafactory’s energy consumption.” That is why, early in the project, Equans teams work with the client to determine the optimal enclosure size, with the goal of optimizing the facilities’ energy efficiency. To achieve very dry air, moisture is removed first through cooling and then via desiccant wheels. “Here, too, we strive to develop efficient solutions by recovering energy to regenerate these desiccant wheels, thereby reducing energy consumption,” adds Alex Authier. Temperature and humidity measurements allow for real-time adjustment of airflow conditions to maintain the required conditions in anhydrous and clean rooms.
“ Filtration, like moisture removal, is a very energy-intensive process. Anhydrous rooms account for between 20 and 30 percent of a gigafactory’s energy consumption. ”
Highly technical devices for a comprehensive product line
Battery production relies on several complementary systems, including the electrolyte storage and distribution system.
This solvent, which is potentially explosive when exposed to moisture, must be handled under an inert gas atmosphere (such as nitrogen). In a humid environment, the lithium salt contained in the electrolyte can, in fact, turn into hydrofluoric acid and damage the product’s physicochemical properties as well as certain parts of the facility. Therefore, care must be taken to ensure that the volume of electrolyte poured at the end of the battery manufacturing process has not been in contact with moisture in the air.
Thanks to its long-standing expertise in chemical distribution systems developed in the microelectronics industry, Equans is able to design, manufacture, and commission electrolyte distribution and storage systems that combine performance, efficiency, and safety—all in full compliance with the environmental and ATEX regulations of the relevant country.
Another key aspect of battery manufacturing involves NMP. Philippe Humeau, head of process engineering at Equans France, explains its role: “To spread the slurry—a type of ink containing rare metals—uniformly, we use a solvent called NMP. After this ink is coated onto an aluminum foil, the coated strip passes through a drying oven at a temperature between 100 and 130°C to evaporate the solvent.”
Equans has developed an innovative technology to treat the air, recover this NMP, recirculate the purified air into the oven, and capture any excess heat to power, for example, the regeneration systems of cleanroom dehumidification units. This NMP recycling system is the subject of a PCT patent filed by Equans.
“ To spread the slurry—a type of ink containing rare metals—evenly, a solvent called NMP is used. After the ink is coated onto an aluminum foil, the coated strip passes through a drying oven at a temperature between 100 and 130°C to evaporate the solvent. ”
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