Shear stress reduction in electrochromic device assemblies
An electrochromic integrated glazing unit (IGU) comprises an electrochromic lite, a glass lite, a spacer, and a sealant. The electrochromic lite can have a first piece of carrier glass, a second piece of carrier glass, and an electrochromic device disposed between them, where the first and second pieces of carrier glass can be offset such that the first piece of carrier glass extends farther than both the second piece of carrier glass and the electrochromic device along a first edge of the electrochromic lite. A sealant can be disposed between the first piece of carrier glass and the glass lite along a first edge of the electrochromic IGU and further disposed between the second piece of carrier glass and the glass lite. An electrochromic laminated glass unit (LGU) with a similar electrochromic lite can contain one or more shear blocks disposed at a first edge of the electrochromic LGU.
1. An electrochromic laminated glass unit (LGU), comprising:
a first substrate laminated to a first piece of carrier glass;
a second substrate laminated to a second piece of carrier glass;
a first electrochromic material disposed between the first and the second substrates; and
one or more shear blocks;
wherein:
the first and second pieces of carrier glass are offset such that the first piece of
carrier glass extends farther than the second piece of carrier glass in at least one dimension;
the first piece of carrier glass extends farther than the first substrate, the second substrate and the electrochromic device in the at least one dimension;
the one or more shear blocks are disposed at a first edge of the electrochromic
LGU, adjacent to both the first and second pieces of carrier glass, at the edge where the
first and second pieces of carrier glass are offset; and
the second piece of carrier glass is supported by the shear blocks when the electrochromic LGU is oriented vertically and is resting on the first edge of the electrochromic LGU,
wherein the shear blocks are affixed to the first and second pieces of carrier glass with sealant.
2. The electrochromic LGU of claim 1 , wherein the sealant is selected from the group consisting of polyisobutylene (PIB), polysulfide (PS), polyurethane (PU), silicone, hot melt butyl (HMB), reactive HMB dual seal equivalent, and combinations thereof.
3. The electrochromic LGU of claim 1 , wherein the shear blocks are L-shaped with the thicker part of the L-shape adjacent to the second piece of carrier glass and the thinner part of the L-shape adjacent to the first piece of carrier glass.
4. The electrochromic LGU of claim 1 , wherein the first or second piece of carrier glass comprise strengthened soda lime glass having a thickness in the approximate range from about 3.0 mm to about 6.0 mm.
5. The electrochromic LGU of claim 1 , wherein the offset between the first and second pieces of carrier glass is from 2 mm to 6 mm.
6. The electrochromic LGU of claim 1 , wherein the first and second substrates are glass or plastic.
7. The electrochromic LGU of claim 1 , wherein the first and second substrates comprise:
borosilicate glass with a coefficient of thermal expansion about 2.2 g/cu-cm;
a thickness from 0.25 mm to 1 mm; and
a greater than 90% probability of withstanding a thermal stress or withstand a thermal
edge stress less than 100 MPa.
8. The electrochromic LGU of claim 1 , further comprising a third substrate, a fourth substrate, and a second electrochromic material, wherein:
the first electrochromic material is disposed between the first and the third substrate;
the second electrochromic material is disposed between the fourth and the first substrate; and
the third and the fourth substrates are attached to each other.
9. The electrochromic LGU of claim 1 , wherein the first and second substrates are laminated to the first and second pieces of carrier glass with a material selected from the group consisting of polyvinyl butyral (PVB), ethylene vinyl acetate (EVA), polyurethane (PU), an ultraviolet activated adhesive, or other transparent or translucent bonding material.