Cross section of the Punched Anode(magnified 500×)

Results of a punching processability test of a lithium-ion battery electrode (Anode, 150 μm, double-side coated)

Lithium-ion batteries are a type of secondary battery designed for repeated charging and discharging cycles. They generate electrical energy through the movement of lithium ions between the cathode and anode. These batteries are widely integrated into electronic devices such as smartphones and laptops, and as a power source for electric vehicles. Despite their extensive adoption, the technology continues to evolve in fierce development competition worldwide, with ongoing efforts focused on improving energy efficiency, extending lifespan, and enhancing overall performance.

If the cathode and anode of a lithium-ion battery come into direct contact, a short circuit can occur. Burrs or sagging on the processed surface may penetrate the separator and touch the opposite electrode. Therefore, strict quality control during electrode processing is essential.

In this test, we used a specimen with a total thickness of 150 μm, consisting of a 8 μm copper substrate with active materials coated on both sides, and conducted a punching test using our precision punching tool with a clearance of 2 μm.

Test Conditions:

Test Specimen

Material: Anode substrate + Copper foil
Thickness: 150 μm（Copper foil 8 μm)

Test Equipment

Punching jig: Nogamigiken’s Handheld Electrode Punch
Diameter: 10.00 mm
Clearance between the punch and the die: 2 μm
Microscope: KEYENCE VHX-6000
Magnification: up to 2500×

Test Results:

Top View of the Punched Anode

  • Top View of the Punched Anode(magnified 20×)
    Top surface full view (magnified 20×)
  • Top View of the Punched Anode(magnified 100×)
    Top surface enlarged (magnified 100×)

    • No burr or deformation is observed.

    Cross section of the Punched Anode

  • Cross section of the Punched Anode (magnified 200×)
    Cross section (magnified 200×)
  • Cross section of the Punched Anode(magnified 500×)
    Cross section (magnified 500×)

    • The copper substrate layer also shows no burr or sagging, and the active material areas exhibit no irregularities.

    The Nogamigiken Technician’s Comment

    • When processing anodes, several issues can occur. Burrs or sagging may appear on the copper foil. Additionally, the active materials coated onto the substrate can experience problems such as collapse or delamination of the layer. However, with the test condition, we achieved excellent results.
       
      Global competition in the battery industry is driving a reduction in the thickness of metal foil used as electrode substrates, which is expected to increase difficulty of processing. It is pivotal to determine optimal processing conditions in conjunction with the selected material and quality standards, as variations in material thickness necessitate different process parameters.
      Test, observation and evaluation by Katsuhiro Morota
    Handheld Electrode Punch