E-mobility: Manufacturing solutions for battery production from SM Klebetechnik

Sealing automotive batteries in e-mobility

Adhesive and sealant applications in battery module and battery pack manufacturing

Production capacity is also being increased in Europe to meet the demand for vehicles with alternative drive technologies. The use of adhesives and sealants plays a crucial role in the production of batteries for electric vehicles.

As a certified supplier to various car manufacturers and their suppliers, SM Klebetechnik offers high-performance application solutions for the production of battery packs.

As early as 2021, the topic was taken up in the form of a diploma thesis entitled “Bonding and sealing in the production of battery modules and battery packs (e-mobility)”. A practical solution for reliably sealing battery packs was developed in collaboration with the Aachen University of Applied Sciences.

Bead geometry

Sealing battery packs with high viscosity butyl sealants

Sealing automotive batteries for use in electric vehicles is an important step in the production process. Precise application of the sealant protects both the interior of the battery pack from environmental influences and the occupants from gases or other toxic substances that can escape if the battery pack is defective. The butyl-based sealants used to seal car battery covers not only seal out air and gas, but are also highly resistant to environmental influences such as salt, stone chipping and even freezing temperatures. Sealant viscosities of 1.5 – 3 million mPa*s are commonly encountered. When applying these high viscosity sealants, it is important to ensure a homogeneous application in a reproducible process in order to achieve a full surface seal. In addition, process and travel speeds of up to 400 mm/s must be achieved to meet the cycle times of the automotive industry.

Bonded glowshield flame protection

In addition to protecting the battery from the environment and ageing, another important consideration is the protection of vehicle occupants in the event of a defect or accident. In order to give vehicle occupants sufficient time to evacuate in the event of an emergency or fire, batteries are required by law to have a fire retardant coating. This coating is achieved using mica shields, which are bonded to the outside of the battery pack using reactive adhesives. In the event of a battery fire, the flames can be prevented from spreading to the vehicle for up to 5 minutes. For this application, moisture-curing polyurethane-based hot melt adhesives are used, which do not melt even under high heat. Application is by a flat spray. A homogeneous layer of adhesive optimises material usage without compromising adhesion.

SM Klebetechnik: Systems fulfil a wide range of requirements in automotive battery production

Based on initial applications in the area of battery pack sealing, SM Klebetechnik optimised its equipment engineering for the specific requirements in this field. The result is a usage-oriented application solution that satisfies the broad range of automotive battery sealing requirements.

SM Klebetechnik’s KP 81 pump application head with its gear pump built into the head has proven effective in applying butyl. The bead module makes it easy to change the application nozzle, thereby enabling different bead patterns. That means both round beads with diameters of up to 20 mm and also other bead geometries such as square or triangular beads are possible.

The integrated gear pump allows for a very short control system between nozzle discharge and pump. This, in turn, makes it possible to apply sealant precisely with minimal pressure fluctuations during application. Moreover, a front closing needle valve ensures clean start-stop action without stringing over the component.

Pump application head KP81

With the KF0170, SM Klebetechnik also offers a suitable application head for surface spraying. This fibre spray head uses heated compressed air to atomise the adhesive, producing a homogeneous application pattern. The maximum application width per head is 220 mm. Larger application widths can be achieved by modular arrangement of several application heads. With interchangeable masking plates, the application head is very low maintenance and can be customised to meet individual customer requirements.

Spray pattern – Fibre spray

Fiberspray-Head KF0170

 SM Klebetechnik offers a wide range of systems for melting and conveying the various adhesives and sealants.
To melt and pump high-viscosity sealants, drum melters for 20 or 200-litre packages are used in the most common applications. Along with the required melting capacity, the drum melter must also have a suitable ram force to achieve continuous mass flow and optimal pump inflow as well as filling level. Its screw spindle drive enables SM Klebetechnik’s GX 78 screw spindle drum melter to melt and pump these highly viscous materials in high discharge volumes.

Reactive hot melt adhesives are applied with pneumatic drum melters and special bag or tank melters. GR Series tank melters are equipped with an integral compressed air dryer to prevent cross-linking of adhesives within the unit. These units also have a reservoir that allows uninterrupted dispensing even when the adhesive is being refilled.

Tank melter GR22

Bag melter GR21

Tests in the technical centre confirm practical suitability

Thanks to close cooperation with leading adhesive and sealant manufacturers, material tests are regularly carried out under real-life conditions in SM Klebetechnik’s own technical centre. The tests confirm the practical suitability of the system technology, as does the feedback from the partner:

„The tests were conducted in the technical centre of SM Klebetechnik in Heinsberg, Germany. The company employs about 60 people and its size makes it a very flexible and active partner for us.

The 200-litre GX7882 screw spindle drum melter system was soon able to apply a perfect sealing seam without any problem. After adjusting the parameters, it also successfully applied sealant to a simulated section with a tight radius. By selecting various nozzles and fine-tuning further machine settings, the system essentially satisfied all requirements with regard to injection quantity, geometry, application rate, etc. This proves the overall suitability of the proposed system. SM Klebetechnik’s systems are already used in the automotive sector and we have agreed in principle to collaborate on future projects – to seal battery housing covers, for example.

We can also envision further collaboration on reactive hot-melt applications, such as gluing mica sheets to plastic battery housings.“

The hot butyl test series shows that the application technology for automotive battery sealing developed by SM Klebetechnik can also melt and pump very high-viscosity sealants in sufficient quantities, thereby satisfying customer requirements. In addition, the use of the KP 81 pump application head during subsequent bead application shows that the existing technology can also be used to apply this sealant. Bead diameter can be modified by using different nozzle diameters and varying the pump speed.



Give us a call at +49 (0) 24 52 / 91 72-0 or send us an email to info@sm-klebetechnik.de – we will be happy to help you!

About SM Klebetechnik

For more than 30 years, SM Klebetechnik has made a name for itself internationally in the development and construction of special machines and standard devices for processing adhesives and sealants.

Our machines for hot melt processing and coating tasks are used successfully in the automotive, mechanical engineering, graphic arts and adhesive tape industries, as well as in the furniture, construction, wood and textile industries. Our units are also integrated into production systems at adhesive and sealant manufacturers and compounders. In our certified, owner-managed company, over 70 employees are committed to the needs of our customers every day.