The world of electromobility and battery manufacturing is rapidly evolving and the manufacturing process demands innovative solutions. Modern EVs use various types of batteries that must be optimized for longevity, performance, and safety. This makes dispensing solutions an advantageous way to assemble them. Use high-performance adhesives, sealants, or thermal interface materials with an efficient dispensing system to boost production efficiency. Thus, you can also reduce weight as well as costs and drive sustainability.
Six common dispensing challenges in battery assembly processes
Over the years, a number of applications have become common in electric vehicle production processes. It started with applications such as a simple sealing application, known from the engine sealing process. These have now evolved into fast-moving innovations revolutionizing the entire production process.
There are many application processes in battery assembly depending on the battery cell type - cylindrical, prismatic, or pouch - and the battery design.
- Cell and sidewall bonding
- Battery tray sealing
- Thermal management
- Fire protection
- Battery cover sealing
- Corrosion protection
Cell and sidewall bonding
Cell stack and sidewall bonding are critical processes in the production of EV batteries. You need to securely join the cells while maintaining electrical insulation and allowing cell expansion during charging and discharging. These processes require precision, speed, and flexibility. Thus, you ensure the production of high-quality batteries. These EV batteries meet the stringent safety and performance standards of the automotive industry.
Challenges in cell and sidewall bonding:
For batteries with prismatic cells, the challenge is to attach the cells to a stack firmly. No heat or force can be applied. The joint must meet the highest demands in terms of application quality, rigidity, and crash behavior. Similar challenges appear when bonding the sidewalls around the cell stack. This is why manufacturers often use two-component (2C) materials for this process. They do not require heat for curing. The application and process quality must be right the first time to ensure a safe bond when using 2K materials.
Our solutions for cell and sidewall bonding:
Atlas Copco’s SCA product line offers dispensing solutions that are highly precise. They avoid air pockets and ensure high process reliability. Depending on the customer's requirements, we offer 1C and 2C applications. 2C applications are often used in cell-to-cell bonding. You do not need external heat for the hardening. The high metering accuracy and mixing quality of our systems allow us to handle even advanced 2C applications with high speed and constant quality.
Battery tray sealing
EV batteries do not like moisture. Any kind of moisture can affect their performance. Depending on the design of the battery, the inner edges of the tray can also let in moisture. Manufacturers can apply materials such as MS Polymers to the inner contours and trim edges to seal the battery from moisture ingress and gas leakage.
Challenges in battery tray sealing:
Complex part geometries and position deviations during production can make accessibility and precision difficult. This can also involve high programming effort. Depending on the part contours, different seam geometries may be required to achieve 100 % tightness.
Our solutions for battery tray sealing:
According to the geometry in the battery tray, our E-Swirl 2AdX applicator can seamlessly switch between bead and swirl applications. The swirl pattern provides an improved material distribution. This is helpful when sealing. Our E-Swirl convinces you with a flexible application distance and easy programming. This applicator enables a stable process window and quality even with difficult accessibility. Combined with our ISRA VISION robot guidance solution SHAPEMATCH3D, we ensure that position deviations of the battery tray are considered before starting the process. The application starts precisely at the correct position.
Battery cells generate heat during charging and discharging. It's important to control and distribute this thermal energy for safety. Thus, you also maintain long-term battery capacity. Apply a thermal interface material (TIM or gap filler) between the battery tray and the cell modules to prevent overheating. This enables active thermal management of large battery packs. The generated heat is dissipated into appropriate cooling structures.
Challenges in the application of thermal interface material:
Temperature management is an essential task in battery manufacturing. You need to operate high-voltage battery cells within a specific temperature range to preserve their performance and avoid overheating. For this reason, apply a heat-conducting paste. To guarantee full thermal conductivity, a bubble-free result is crucial. This is a challenge as the liquid gap filler material is applied at high volumes. On top of that, the material is also highly abrasive and can wear out the equipment quickly.
Our industrial dispensing solutions offer precise metering technology and system components. They are designed to handle high volumes of abrasive materials at a high productivity level. The material needs to be applied with great precision. With an optimized pattern we avoid air pockets in the application process. Adding visual 3D scanning of the battery tray we determine the exact amount of material needed. This saves expensive material and detects dispensing errors in width, position, and bead continuity immediately without adding cycle time.
In the unlikely event of EV battery cells igniting, there is a risk that they will burn through the battery cover. For example, the latest safety regulations in China specify that a passenger must have at least five minutes to leave the vehicle in case of a fire emergency. One approach is to cover the battery lid with a layer of a liquid-applied fire-resistant material. These are often two-component (1K) materials.
Challenges in fire protection:
The material layer must have a defined thickness on the entire surface of the cover. Gaps and overlaps must be within tight tolerance ranges to avoid issues in downstream production processes. Spray applications of materials like epoxy have many disadvantages. Material particles in the air are a health risk. The alternative is a flat stream application. However, applying 2K materials with flat stream has been difficult up to now.
Our solutions for fire protection applications:
We have developed a solution to apply 2K materials in a sharp-edged flat stream. Our SCA FlexS.Seal applicator mixes two components with high precision. An additional needle valve at the nozzle ensures that the mixed material is dispensed with the right pressure. We optimized the valve to avoid material residues that could affect quality. Thus, we achieve a fast, accurate, and uniform application on large surfaces with clean beginnings and ends. You reduce health risks, material waste, and masking with no overspray issues.
Battery cover sealing
Harmful gas evaporation and humidity ingress could impact the safety and performance of EV batteries. To prevent this, battery manufacturers require several sealing steps in the assembly process. And all that with quality assurance in mind, even with part deviations and difficult contrast ratios.
Challenges in battery cover sealing:
When it comes to cover sealing, an uninterrupted bead, precise bead beginnings and ends, and an even bead height are mandatory. At the same time, the seam must be reversible to enable repairs. Due to its permanently elastic properties, hot butyl is well suited for this. However, you need to heat up the material to 160 °C for optimal processing. Visual quality inspection is challenging with black material seals on black-coated surfaces.
Our solutions for battery cover sealing:
Our Atlas Copco hot meter optimally tempers hot materials for a perfect cover sealing result with clean bead beginnings and ends. The inline 3D vision inspection solution RTVision.3d inspects the width and height. This solution also controls the continuity of the bead during the application as well as the applied volume. It also monitors the distance from the center of the bead to the component edge to check accurate positioning. Thus, we can detect any deviations in real time. Thanks to laser technology we can easily inspect the bead despite challenging color mixes (e.g. black on black).
At the end of the process, battery manufacturers need to seal the critical areas of the battery to avoid corrosion. State-of-the-art battery designs have many surface breaks, trim edges, and joints. For example, mechanical cover-to-tray joining can cause slight damage to the lid’s coating. At these spots, moisture can enter, and there is a high risk of corrosion. To protect these areas, you can apply anti-corrosion materials such as special waxes.
Challenges in corrosion protection applications:
The application process at the surface of the battery with its many contours, edges, and joints is challenging. Common manual or automated spray applications lead to manual rework, masking effort, and material waste. This affects the productivity and the quality of the corrosion protection process. On top of that, serviceability aspects may need to be considered. If the joining elements are covered with material, loosening the screws for repairs is difficult.
Our solutions for corrosion protection applications:
IDDA.Seal is an intelligent and dynamic drop application that can also process waxes. You can individually control every single droplet. This allows for the highest precision and a fully flexible bead geometry. We can perfectly adjust the bead width and thickness to your requirements. You can apply the material as thinly and precisely as possible. You use only as much material as necessary. Thus, you cut manual rework and material usage to a minimum. For example, you can omit the head of the joining element. This allows clean loosening of the screw for repairs.
Your EV battery manufacturing challenge is our industrial dispensing solution
With our extensive knowledge of industrial trends, challenges and opportunities, our technical experts and our broad network, we can support you in significantly improving your processes, your production and profitability.
Joining processes can vary a lot. Therefore, we offer comprehensive testing and consulting before buying a dispensing solution. Our global network of 13 Innovation Centers offers places where we innovate and collaborate on joining challenges together with our customers and partners. They are designed to accelerate your innovation journey.
Our Innovation Center offering at a glance:
- Application and process development
- Material testing
- Joint analyses
- Technology integrations
- Pilot productions
- Virtual trials
and much more!