Desired Characteristics of a Battery Separator One of the critical battery components for ensuring safety is the separator. Separators (shown in Figure 1) are thin porous membranes that physically separate the cathode and anode, while allowing ion transport.
In punch test of the whole battery cells, due to the friction from cathode and anode particles, the separator is mostly expected to fail in Mode A, and not to reach Mode B. With the start of thinning and appearance of transparent section, friction would lead to instant localization.
At present, the thickness of a general-purpose rechargeable battery separator is required to be 25 μm or less, and the battery separator used in an electric vehicle or a hybrid electric vehicle is required to satisfy a large current discharge and a high capacity of the battery, and is generally as thick as 40 μm [, , , ]. 2.2.
The mechanical integrity of battery separator is critical for prevention of internal short circuit. A better understanding of the mechanical behavior and failure mechanisms of the separators may assist in explaining an apparently conflicting response.
We present a non-invasive procedure for quality control of battery separators in the early stage of the production line. In this method we apply a high voltage on the dry electrode assembly and measure transient partial discharge events.
Since organic solvents are often involved in the electrolytes in the rechargeable battery system, the separator material is required to be corrosive-resistant to organic solvent.