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Testing of Separators

Separators play a decisive roll in the efficiency, life cycle, and safety of lithium-ion battery cells. The most important test requirements on separators are covered by tensile and puncture tests.

Test requirement Testing systems Specimen preparation

Test requirements

  • Separators play a decisive roll in the efficiency, cycle life, and safety of battery cells. Their job is, on the one hand, to reliably isolate the electrodes from each other electrically and, on the other hand, to ensure energy flow via lithium-ion exchange. The most important testing requirements on separators are covered by the tensile test to ISO 527-3 and ASTM D882 and puncture tests to EN 14477, ASTM D5748 and ASTM F1306. These tests are also performed in an electrolyte-wetted state to determine the mechanical characteristic values as realistically as possible.
  • Another important behavior of the separator in interaction with the electrodes is the determination of the coefficients of friction between the electrode coating and the separator. The corresponding characteristic values are particularly important for setting the production parameters in the winding processes.
  • In addition to tests at room temperature, tests are increasingly being performed at near-operating temperatures in the range of -20°C to + 50°C.

ZwickRoell testing solution

  • For these tests with low test loads up to 5 kN, the zwickiLine proves to be the ideal solution for standard-compliant testing, as well as for tests in the field of research and development. The load frame is compatible with all necessary tooling and enables quick changes between tests.
  • For tests requiring the use of a temperature chamber, the AllroundLine provides the required test area size to combine the chamber and tools.
  • The strip cutter for battery foils and films is the perfect tool for specimen preparation.

Additional information

Tensile properties of films and sheets
ISO 527-3, ASTM D882, ASTM D5323
to Tensile properties of films and sheets
Puncture resistance of films and sheets
EN 14477, ASTM F1306
to Puncture resistance of films and sheets
Coefficient of friction of plastic films
ISO 8295, ASTM D1894, JIS K 7125, DIN 53375 (withdrawn)
to Coefficient of friction of plastic films
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