After the single battery cells have been stacked together in modules, they need solid framing for stabilization and collision protection. This reinforcement is done with lateral braces. However, common multi-material joining techniques such as welding are not suitable in this instance. Alternative solutions are required.
Electric Vehicle (EV) battery cells are sensitive to heat and must be mounted in a clean environment. Welding, for example, is a common joining technique but is not a viable solution since it introduces both heat and the risk of contamination with welding splatter.
Advantages of self-pierce riveting
Module assembly with Henrob self-pierce riveting
The solution is to apply a clean cold joining technology such as self-pierce riveting (SPR). SPR is a method of joining two or more pieces of material using a rivet without needing a pre-drilled hole. The basic self-pierce riveting process involves driving a rivet at high force through material layers into a die which causes a rivet tail to flare out and form a tight, self-sealed joint. The result is a short cycle joining process with high strength characteristics and a visibly checkable joint.
Aside from meeting the technical requirements for module assembly, self-pierce riveting is also operator and environment-friendly. No filing debris, no heat, no sparks, no hazardous vapors, and this method is energy efficient.
High joint inegrity, structural stiffnedd and rigidity with a short assembly cycle time
With the Henrob product line, we offer a comprehensive range of self-pierce riveting systems that combine high joint integrity, structural stiffness, and rigidity with a short assembly cycle time. Our in-house Applications Lab team develops flexible rivet solutions in close partnership with customers to offer the best solution needed for the supplied materials. Sheets of varying materials such as aluminum to steel, composites to metals, and similar materials (steel to steel and aluminum to aluminum) can be joined. Our solution also conserves energy by using only a four-bar operating pressure.
The SPR can be combined with a die check camera for quality assurance purposes. The camera continuously inspects the integrity of the die, thereby increasing efficiency and reducing downtime, factors that also reduce CO2 emissions.
Henrob self-pierce riveting system with die check camera
User friendly and flexible manufacturing process
A die changer for robot-mounted riveting tools can also be added to the process. This enables an upset die to be automatically changed without the need for operators to enter an automated cell. The advantage is an even more flexible manufacturing process which lowers the overall cost of operations.
Our self-pierce riveting solution is a user-friendly, short time-cycle, reliable and non-intrusive technology that offers operational flexibility and high structural integrity. When combined with die check and die changer technology, downtime, productivity, and quality assurance are automated and optimized.
Watch the video to learn more about our solution: