A Li-ion separator typically has a thickness of 25 micrometers (μm). This specific dimension is crucial for the performance and safety of lithium-ion batteries.
Key Characteristics of Li-ion Separator Thickness
The thickness of a battery separator is a critical design parameter, directly impacting a battery's energy density, power capability, and safety. A thinner separator allows for more active material within the battery cell, potentially increasing energy density. However, it must be robust enough to prevent short circuits between the anode and cathode.
Detailed Separator Specifications
Beyond thickness, other properties define the functionality of a Li-ion separator. For instance, a common type of separator made from Polypropylene (PP) exhibits the following technical properties:
| Material | Polypropylene (PP) |
|---|---|
| Thickness | 25±2 μm |
| Width | 60 mm |
| Areal density | 13.2±1.0 g/m² |
| Air Permeability | 350±100 s/100ml |
These specifications indicate the precise engineering required for battery components. The thickness tolerance of ±2 μm highlights the manufacturing precision for these thin films.
Importance of Separator Properties
- Thickness: Directly affects ion transport pathways and the physical separation between electrodes. Optimal thickness balances safety with energy density.
- Material: Polypropylene (PP) is a common choice due to its chemical stability, mechanical strength, and ability to form microporous structures essential for electrolyte absorption and ion flow.
- Areal Density: Relates to the weight per unit area, indicating how lightweight the separator is, which contributes to the overall battery weight.
- Air Permeability: Measures the rate at which air passes through the film, indicating its porosity. Sufficient porosity is vital for electrolyte uptake and ion conductivity, which in turn impacts the battery's power capability.
These properties collectively ensure that the separator can facilitate efficient ion transport while physically isolating the electrodes, preventing direct electronic contact that could lead to thermal runaway or short circuits.
