Vaisala Enhances Rechargeable Battery Manufacturing with Fast-Response Dew Point Measurements

VANTAA, Finland, July 15, 2024  — As the world transitions to electrification and green energy, the demand for more powerful and safer rechargeable batteries—such as lithium-ion, sodium-ion, and solid-state—is rapidly growing. Vaisala, a global leader in measurement instruments and intelligence for climate action, is addressing this need by enhancing manufacturing processes with accurate, highly responsive dew point probes.

The midstream stage of battery manufacturing involves electrode production, cell assembly, and cell finalization. It is during these steps – in dry rooms, dry booths, and glove boxes – that humidity control is especially important to prevent unwanted reactions. These include lithium-forming lithium hydroxide and hydrogen gas, lithium salt-forming hydrogen fluoride (HF), and electrolyte-generating corrosive byproducts. Effective drying processes are critical to:

• Protecting the safety of people and materials: The chemicals used are sensitive to moisture and present an explosion risk if exposed to elevated moisture levels.
• Maximizing the yield of the process and maintain quality: Excessive moisture negatively impacts the quality and lifetime of batteries.
• Optimizing energy consumption: Maintaining dry room ambient dryness at optimal levels avoids costly over-drying and under-drying.

Innovative Dew Point Measurement Solutions

The ambient dew point temperature in dry rooms is maintained at around -30 ºC to -40 ºC. Low humidity is controlled by a high-end dryer that pushes dry air into the room. This is one of the most energy-intensive parts of the whole battery manufacturing process, so minimizing over-drying is key to the plant’s overall energy efficiency.

The dew point sensors in the dryer need to be highly responsive to control the dryer quickly and accurately in order to avoid under or over-drying. It is important to note that sensor accuracy alone will not be enough to avoid these issues. A probe with a fast response time, and without the complex internal measurement control loops of some analyzers, makes all the difference in dryer and overall dry room control. The volume of air being dried and pushed through is huge, so the energy consumption can easily skyrocket if the drying process is not optimized.

Newer technologies such as all solid-state batteries may require drier conditions with the dew point temperature as low as -80 ºC in individual processing steps. These steps are usually performed inside dry booths or glove boxes because it is not economical to dry the whole dry room to the same extremely low dew point level. Humidity levels in dry booths and glove boxes are monitored at critical points.

Vaisala’s DRYCAP® Technology

Vaisala’s DRYCAP® technology is the world’s most used technology for dryer monitoring and control. It is a field-proven innovation that provides accurate, stable, and fast-response dew point measurement with minimum drift. Vaisala has achieved this leading position not just because of innovation, but also because of a firm commitment to product quality and reliability, with short lead and delivery times, combined with world-class levels of service.

Versatile, cost-effective solutions for the whole process

The sensors needed to monitor humidity in the drying process of midstream battery manufacturing don’t need to be expensive ultra-high precision laboratory-level devices. For example, the miniature dew point transmitter DMT143 is a simple, cost-effective device for accurate, stable, and fast-response dew point measurements in air dryers and glove boxes.

Vaisala adds value by providing holistic systems and packages, such as the Vaisala Indigo ecosystem. The core of the Indigo offering is the transmitters and compatible probes with DRYCAP® technology. Indigo family products are versatile and easy to install, use, and service. Transmitters that support various fieldbuses and include built-in displays and other advanced features can be combined with probes such as the DMPx. This enables you to measure accurately and reliably in demanding processes with harsh chemicals, high temperatures, and ultra-low humidity. This is why the Indigo ecosystem offers the best solution for humidity monitoring and control in midstream battery production.