High Voltage Discharge for Detection of Intercalated Air and Gas in Thin Film Energy Generation and Storage Devices
High voltage gas discharge visualization allows effective quality assurance of bonded seams in articles that contain working fluids or gases sealed in dielectric or metallized dielectric casings or pouches.
As flexible polymers find increasing use in the encapsulation of devices such as batteries and solar cells, better ways to assure the integrity of the encapsulation are needed. Enerize has developed a proprietary nondestructive, non-contact gas discharge visualization technology for assuring the integrity of flexible encapsulation materials, seals and membranes such as are used in polymer-substrate solar cells, lithium batteries, and fuel cells.
In gas discharge visualization, the article being tested is subjected to a high-voltage pulsed electric field formed between the positive electrode and the metallic layer of a multi-layer article casing. A polarized dielectric plate placed between the positive electrode and the test article. The high voltage pulse discharge produces an electromagnetic field that creates an image on photographic film. A proprietary transducer design produces a novel orientation of the high voltage discharge field, which greatly improves performance as compared to other methods for detecting flaws and leaks.
The main advantages of Enerize Corporation gas discharge visualization are:
- Less expensive than microscopic inspection,
- Safer than x-ray technology
- Non-contact method,
- Capability to view defects with a real time camera,
- Capability to detect flaws in packaging that requireshermetic bonding or sealing,
- Capability to detect holes or voids with a single measurement that tests the entire exposed surface area,
- Capability to test thin membranes or foils with defects which penetrate through the material,
- Capability to test conductive and dielectric material, as well as multi-layer structures,
- Eventual capability to view defects in real time with a camera installed on automated production lines.
As compared to other methods such as microscopic examination, x-ray visualization and pressure testing, the following advantages should be noted:
- Microscope allows only a limited area to be viewed for small defects.
- X-ray analysis requires safety precautions.
- With liquid penetration depending on the material, the penetrant can damage the test articles.
- Pressure or vacuum testing require the use of an inert gas inside of the test fixture, and depending on the sample, the gas used may damage some samples.
As an application example, Enerize gas discharge visualization has been used to determine seal integrity for sample materials with thickness ranging from 0.05 mm to 12 mm. Defects detected were as small as 0.05 mm in diameter. The minimum size or detection limit for pinholes or voids in a seal or membrane is on the order of 3 mm in diameter. Time required for such measurements is on the order of 2-3 sec. as estimated with a real time camera.
The schematic diagram to the left shows the Enerize Corporation seal test apparatus comprising a high voltage pulse generator 1
, test article with a metallized polyethylene casing 2
, article operating medium 3
, article weld seam area (4
) with a discontinuity (faulty weld) air gap indicating seal failure 5
, photo film 6
, dielectric polarized plate 7
, and electrode of device 8