FOCUS ON STAMPING
Prismatic cells are primarily used for electric powertrains in hybrid and electric vehicles .
Each battery case also needs a lid , which is manufactured in a stamping operation .
“ The part itself is not very complicated ”, Röver says , “ but in the downstream process , a lot of assembly work has to be done .”
However , some steps can be integrated into the forming process – the burst valve , for example : “ Usually , a foil is applied here . But the metal can also be made to pop up at a defined pressure by stamping a corresponding geometry into the lid .” This is possible at high speeds e . g ., on a Schuler 200-metric-ton stamping press .
The forming factor
With impact extrusion , the slug is punched into a die , resulting in the aluminium flowing backwards
steps which will limit the output , since you also have to transfer the part from one forming station to the other .”
In the second process , the aluminium slug is utilised almost in its entirety . Thanks to the impact extrusion process , the prismatic case can be produced in one shot , followed by just wall-ironing ( to achieve the final geometry ) and a trimming operation .
“ This is a solution which is really applicable for the mass production of 20 or 30 million parts per year ,” Röver pointed out . While deep drawn cases can reach a production rate of 20 to 30 strokes per minute , impact extrusion can achieve an output of up to 100 . “ The cost-toperformance ratio is better because you need fewer operators and a smaller footprint .”
A turnkey solution
With impact extrusion , the slug is punched into a die , resulting in the aluminium flowing backwards . Schuler has already sold more than 700 presses with this technology , when the company started to apply it to the manufacture of batteries about four years ago . The thickness of the can is reduced by wall-ironing in the next step . The geometry can therefore be calibrated at the same time .
Trimming is done by cutting from the inside of the container , so that the burr is on the outside . In this way , the content is not damaged when it is later filled into the battery . Since a lubricant has been applied to the slug at the beginning of the process , the cans must be washed and dried at the end of the line . The geometry and surface of the final product is finally inspected by cameras .
“ In our R & D department , we can do a simulation of new sizes , geometries and materials of the cells ,” Röver added . Schuler supplies the production line as a turnkey solution including tools , integrated control unit and full service . According to the company ’ s Smart Press Shop concept , each of the machines in the line is connected to a data loft . The information on runtime and from visual inspection can be used for applications such as process monitoring and preventive maintenance , for instance .
The Feintool Group ’ s Smartline EV 3.8 high-speed press from Schuler , at its new production site in Taicang ( China ), for the manufacture of interlocked electric motor cores .
Schuler offers customised technology in all areas of forming — from the networked press to press shop planning . In addition to presses , its products include automation and software solutions ; dies , process expertise and service for the entire metalworking industry . Its customers include automobile manufacturers and automotive suppliers , as well as companies in the forging , household appliance and electrical engineering industries . Presses from the Schuler Group mint coins for more than 180 countries .
In the 2019 fiscal year , Schuler generated sales of € 1.136 billion . Founded in 1839 Göppingen , Germany , Schuler AG has approx . 6,000 employees at production sites in Europe , China and the Americas , as well as service companies in more than 40 countries . The company is majority-owned by the Austrian ANDRITZ Group .
. schulergroup . com / battery
62 | sheetmetalplus . com | ISMR September 2021