Contributed Commentary by Scott Pratt, Application Specialist, Temperature Control, Thermo Fisher Scientific
November 11, 2022 | Battery manufacturers are constantly optimizing their processes to meet the increased industry demand for batteries due to the rise in smart technology and electric vehicle development. However, only a few are aware of the impact these enhancements can have on their temperature-cooling needs. As improvements are made, battery manufacturers should consider how their manufacturing processes may change over time to increase their production and how to optimize temperature control systems to meet future requirements.
Addressing the Process Cooling Needs of Battery Manufacturing
As the industrial world works to increase its positive environmental impact through developing more eco-friendly solutions—such as electric vehicles and energy storage systems—it mustn’t be forgotten that the large-scale manufacturing processes behind these green products must be equally optimized.
Much of the energy used for battery manufacturing becomes heat that must be removed from the process. Supplying cooling water to remove the waste heat on a facility-wide basis is an area where much can be done to lower the cost and carbon footprint of the manufacturing process.
Consideration of compressor-less recirculating heat exchangers (HX), which offer an efficient way to provide cooling water to critical manufacturing equipment, can be a helpful step in the transition to greener manufacturing. They’re simple devices and have been around for a long time, but many companies still miss out on the environmental benefits they offer. They are energy efficient, using substantially less power than a compressor-based cooling system of similar capacity! They are available in many cooling and pumping capacities, compact, and easy to use and repair—presenting a strong social and business case to manufacturers for their more frequent use.
Of course, recirculating heat exchangers require a secondary source of cooling water (facility water). The best cooling method for facility water will largely depend on factors such as a manufacturer’s operation scale and geographic location. For example, a Gigafactory in humid, sub-tropical Texas would likely have a different method to cool facility water than a Gigafactory in more temperate Berlin.
Taking Advantage of Eco-Friendly Solutions
New Gigafactories can design with the latest environmentally friendly methods to cool facility water rather than rely on well, municipal, or rooftop refrigerated water systems. For example, these eco-friendly water-cooling systems may use storage tanks and water-to-air heat exchange during the cooler nighttime hours, store the hot water for other processes, heat parts of the facility that require it, or use below-ground geothermal cooling. The goal here is to reuse a limited resource—water—while also minimizing the carbon footprint of returning that water to a usable temperature between uses.
But even when traditional facility water—such as well, municipal, or rooftop refrigeration—is being used, recirculating heat exchangers can still use that system while also providing many physical and performance advantages to the manufacturing facility and process itself.
Ensuring Reliability for Battery Manufacturing
Manufacturing equipment and products that use facility water for cooling can be damaged by condensation, particulates that clog cooling passages, dissolved minerals causing scale, low pH that causes corrosion and galvanic coupling, overheating, or variable and insufficient flow rates.
By putting a compressor-less recirculating heat exchanger between the facility water cooling loop and each tool, physical damage from the above factors can be prevented. Also, the HX control compensates for facility water temperature variations throughout the day, further preventing unwanted condensation and manufacturing variations. In addition, the flow and pressure rates are also set and maintained for each tool individually.
A couple of examples of battery manufacturing applications that can benefit from using a heat exchanger include:
- Mixers are used to combine electrode material. A stable temperature and flow to a mixer maintain the slurry at the correct temperature and viscosity, ensuring consistency from batch to batch.
- Lasers in winders that notch or cut the electrode and laser welders are used for welding cell assemblies. Here, a stable flow and temperature maintain a more consistent beam.
What to Consider When Selecting a Recirculating Heat Exchanger
When selecting a recirculating heat exchanger, one should remember that a temperature control unit, such as a recirculating heat exchanger or refrigerated recirculating chiller, comprises three selected systems based on application and facility criteria. Therefore, the first system to consider is the refrigeration or cooling system, which, in this case, is the internal water-to-water heat exchanger itself. The second is the pumping system, and the third is the control system.
The application requirements and facility specifications used to select the three heat exchanger systems for any tool or application can be distilled down to the following:
For the application:
- Application Setpoint: Inlet water temperature or temperature range for the device or application requiring cooling
- Heat load: The amount of energy in watts or kilowatts removed
- Flow: The amount of flow needed to remove the above heat energy
- Pressure: The pressure difference between the supply and return of the HX required to achieve the above flow. This measure must include the additional pressure loss caused by the plumbing to and from the application!
- Special requirements: This is a “wild card” because the list could be nonexistent or exceptionally long. Some examples of special requirements could be a serial or analog remote operation, flow control, pressure control or safety, time-to-temperature, etc.
For the facility:
- Facility water temperature: The temperature of the water to be used to remove heat from the recirculating heat exchanger
- Facility water available flow: The flow that is available to cool this application
- Facility water pressure differential: The difference in pressure between the facility water supply and return
The size or model of the required heat exchanger is determined by supplying the HX manufacturer with the temperature delta between the facility water temperature and the application setpoint temperature, along with the heat load. These are compared to performance charts to see which model has the required cooling capacity. The available facility flow and pressure differential are then compared against what is required by the heat exchanger to determine if it will have enough cooling water. Finally, the application flow and pressure numbers are compared to the available pump performance curve(s) to ensure enough flow to the tool.
While an air-cooled or water-cooled refrigerated recirculating chiller could provide many of the same benefits (and their use is sometimes required to meet the application requirements), they are more complex, more expensive, have a larger footprint, make more noise, use more power, and may use refrigerants that advance climate change if/when they end up in the atmosphere. In addition, the air-cooled refrigeration system would add substantially more heat to the room it is in, which would also have to be dealt with by the HVAC system requiring more energy.
Crystalizing the Benefits
Heat exchangers’ unique qualities create efficiencies across the manufacturing process, which will be particularly important for battery manufacturers, given the increased demand across automotive and industrial applications. They provide clean water at the precise temperature, flow, and pressure, have a low cost per kilowatt of cooling with much lower energy usage than refrigerated solutions, and their simplicity increases reliability. Heat exchangers also allow manufacturers to avoid refrigerants with high global warming potential.
Heat exchangers are compact machines without compressors or fans, meaning that they use less floor space, shipping them is easier, cheaper, and more eco-friendly, and repairing them is easier, lowering the total cost of ownership. More broadly, optimizing the large-scale battery manufacturing process can ultimately help companies whose goals align with critical environmental, social, and governance criteria.
Scott D. Pratt is a Thermo Fisher Scientific application specialist for temperature control. Pratt has more than 25 years at Thermo Fisher Scientific and has extensive knowledge of the latest advancements in temperature control technology and helps customers optimize their cooling and heating applications with outstanding performance and innovative solutions. He can be reached at scott.pratt@thermofisher.com.
