K-Flow battery cover to tray joining illustration

Flow drill fastening for electric vehicles

Learn more about our flow drill fastening applications for battery assembly

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Challenges in battery assembly:

Joint strength and leak tightness
Removable cover for service requirements
Repeatable fastening/tightening
Electrical contacting
One-sided access
Large series production

Our solution for cover-to-tray joining:

Flow drill fastening meets high standards for joint strength and crash performance. With our K-Flow technology, the battery cover can be mounted to the tray with single-sided access. The joint is leak tight between fastener and sheet as well as between both sheets and it can be combined with a liquid gasket. At the same time, it is detachable to facilitate maintenance and dismantling. The metallic components are in a conductive bond and form a Faraday cage, which prevents electromagnetic interference. With short cycle times and high process reliability, it is suited for large series production.

Two layer stack with clearance hole

By using a clamping part with clearance hole, thicker stack-ups with up to four layers can be joined with flow drill fastening. The upper layer can be aluminum or even high-strength steel (HSS). Since no upcoming material needs to be accommodated by the joining element, a cheaper flat head fastener can be used. However, the position of the robot is very important to exactly meet the clearance hole. If used with adhesive, a stitch bead application is recommended to avoid squeeze out. This joint variant is commonly used for applications where serviceability is a priority, for example cover to tray joining in battery assembly for electric vehicles. Due to the clearance hole in the cover sheet, the cover can be easily disassembled and reassembled several times and remain leak tight.

Joint properties (for reference only):

Two layer stack
Clamping part with pre-hole
Materials: Aluminum 2.0 mm / Aluminum 4.0 mm
Fastener: M5x20 internal torx

Learn more about battery joining:

Battery assembly with self-pierce riveting

Adhesive dispensing solutions for battery joining

Six things you should know about battery joining

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More information about our products and services:

K-Flow system solution

Learn more about our flow drill fastening system components

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