BACKGROUND

[0001] The present disclosure is directed to a

dielectric separator compressor for use in a secondary battery assembly.

[0002] A secondary battery is configured such that a cathode and an anode having an active material layer, which is formed by one of; coating an active material with a binder and laying a membrane containing active material on a collector, are connected via an electrolyte layer. The cathode and anode so connected are contained in a battery case .

[0003] In general, secondary batteries (electrochemical batteries) such as lithium ion secondary batteries include an electrode group comprising a positive electrode, a negative electrode and a separator for electrically

insulating the positive and negative electrodes from each other and for retaining electrolyte.

[0004] The separator functions to prevent a short- circuit between the positive and negative electrodes during normal operation so as to ensure safety of the battery.

SUMMARY

[0005] In accordance with the present disclosure, there is provided a dielectric separator compressor comprising a dielectric sheet having a first side and a second side opposite the first side. A first metal screen is coupled to the first side of the dielectric sheet; and a second metal screen is coupled to the second side of the dielectric sheet . [0006] In another and alternative embodiment, the dielectric separator compressor further comprises an adhesive applied between the first metal screen and the dielectric sheet and the adhesive is applied between the second metal screen and the dielectric sheet.

[0007] In another and alternative embodiment, the adhesive is applied to at least one cross-over intersection of each of the first metal screen and the second metal screen .

[0008] In another and alternative embodiment, the first metal screen and the second metal screen comprise a

plurality of windows, the windows being in window registry.

[0009] In another and alternative embodiment, the dielectric sheet comprises a dielectric material, having electrical insulating characteristics.

[0010] In another and alternative embodiment, the first metal screen and the second metal screen comprise a

stainless steel mesh material.

[0011] In another and alternative embodiment, the stainless steel mesh material comprises a 160, 100 and 30 mesh square weave metal screen.

[0012] In another and alternative embodiment, the dielectric sheet comprises a porous dielectric material, having electrical insulating characteristics.

[0013] In another and alternative embodiment, at least one of the first and second metal screen comprise one of a plurality of metal screens sintered to comprise a single screen with aligned window registry.

[0014] Other details of the dielectric separator

compressor are set forth in the following detailed

description and the accompanying drawing wherein like reference numerals depict like elements. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 is a fragmentary side view of an

exemplary dielectric separator compressor;

[0016] Figure 2 is a top plan view of an exemplary rigid compression screen;

[0017] Figure 3 is a top plan sectional view of the exemplary woven screen segment of the exemplary rigid compression screen.

DETAILED DESCRIPTION

[0018] Referring now to Figure 1, shows an exemplary dielectric separator compressor 10. The dielectric

separator compressor 10 comprises a dielectric sheet 12 between a first metal screen 14 and a second metal screen 16. An adhesive 18 couples the first metal screen 14 to an upper surface 20 of the dielectric sheet 12. Adhesive 18 also couples the second metal screen 16 to a lower surface 22 of the dielectric sheet 12. The first metal screen 14 and the second metal screen 16 are aligned in a window registry. In an exemplary embodiment each screen, 14, 16 may comprise one of; one and a plurality of metal screens sintered to comprise a single screen with aligned window registry .

[0019] The dielectric sheet 12 can comprise one of;

impermeable and porous plastic film made of any variety of dielectric materials. The sheet 12 can be a polyester film such as Bi-axially-oriented polyethylene terephthalate (BoPET) which has excellent properties of high tensile strength, chemical and dimensional stability and electrical insulation. Other materials include porous PTFE high density polyethylene (HDPE) , polyethylene (PE), polyimide (PI) and the like. The dielectric sheet 12 prevents the conduction of electrical current through the sheet.

[0020] Figure 2 shows a simplified schematic top plan view of the first metal screen 14 and second metal screen 16 in the form of a planar, rigid compression screen 24. The screen 24 defines locations for uncompressed sections between contiguous segments 28, 30, 32, 34 of the screen 24, wherein the contiguous segments 28, 30, 32, 34 are configured to be cooperatively positioned to define open areas 36. Contiguous segments 28, 30, 32, 34 are configured to be the raised pattern for the compressor 10. A

perimeter 38 of the screen 24 matches a perimeter (not shown) of the sheet 12.

[0021] Figure 3 shows a segment of the screen 24, which may also be referred to as a square weave cloth 24, that may be used to form a plurality of connecting areas 42 (shown in Figure 1) for a pellicle (not shown) that can be coupled to the dielectric separator compressor 10. Wherever strands 44 form cross-over intersections 46 the

intersections effectively form the connecting areas 42 that compress the galvanic pellicle against an electrically conductive surface of an electrode (not shown) . The woven screen 24 may also include a weave defining open squares (windows) 48 that make up greater than about 60% to about 75%, and preferably about 65%, of a projected window planar surface area defined by the woven screen 24. The open squares define the uncompressed sections (not shown) of the galvanic pellicle. Additionally, wire strands 44 making up the woven screen 24 may be made of materials either a metal material and/or a dielectric material.

[0022] The woven screen 24 can be fabricated from a 160, 100 and 30 mesh stainless steel square weave metal, having 20 micron, 52 micron and 303 micron wire respectively. The woven screen 24 includes the dimensions, tolerances and structure that produce the thickness and cross-over

intersections 46 with window 48 spacing that meet a criteria of less than 10% of an active membrane gets compressed in a cell structure. Also the volume factor of the screen 24 can be about 3% and less after being

assembled .

[0023] In assembling the dielectric separator compressor

10, the adhesive 18 is applied to the wire cross-over intersections 46 on a single side of the metal screens 12, 16. In an exemplary embodiment, printing methods, such as a plate and roller method, can be employed to apply the adhesive 18. In some cases, multiple adhesive 18 coatings may be required. The dielectric sheet 12 is adhered to the side of the metal screen 14 containing the adhesive 18. The second metal screen 16 has adhesive 18 applied to the intersections 46 and is adhered to the dielectric sheet 12 opposite the first metal screen 14 in window registry, such that the first and second screens windows 48 are in

alignment. This configuration forms a 3-layer sandwich of considerable strength. The sheet 12 and screens 14, 16 can be cut to any profile shape.

[0024] To finish the assembly, the dielectric sheet 12 material located in each window 48 is one of; removed if impermeable and left intact if porous. In an exemplary embodiment, the sheet material can be burned out by use of a hair dryer, blowtorch, a laser and the like.

[0025] The dielectric separator compressor 10 can be installed between electrodes. The compressor 10 can be utilized to apply sufficient pressure to obtain an ultralow electrode resistance. [0026] There has been provided a dielectric separator compressor. While the dielectric separator compressor has been described in the context of specific embodiments thereof, other unforeseen alternatives, modifications, and variations may become apparent to those skilled in the art having read the foregoing description. Accordingly, it is intended to embrace those alternatives, modifications, and variations which fall within the broad scope of the appended claims.