Low Stress-Inducing Heat Sink
A low stress-inducing heat sink may reduce thermally induced stress and strain in the heat source. The low stress-inducing heat sink may be made of materials with low thermal conductivity. The heat sink may have in-plane flexibility and hence reduce thermally induced stress and strain generated in the heat source and at the interface of the heat sink and the heat source.
1 . A heat sink, comprising:
a plurality of protrusions with surfaces, said surfaces suitable for direct thermal communication with a heat source, and said surfaces having surface areas;
wherein a sum of said surface areas is less than an area defined by a set of outer-most coordinates of said surfaces.
2 . The heat sink of claim 1 , wherein said plurality of protrusions have one of pin-like configurations, tear drop configurations, triangular configurations, rectangular configurations, frustum pyramid configurations, frustum cone configurations, cylindrical configurations, or fin configurations.
3 . The heat sink of claim 1 , further comprising:
a base sheet; wherein
said protrusions are cut from said base sheet; and
said protrusions are bent upwardly away from a plane formed by said base sheet while a bottom portion of each of said protrusions remains attached to said base sheet.
4 . The heat sink of claim 1 , wherein said heat sink is less rigid mechanically than said heat source.
5 . The heat sink of claim 1 , wherein a pattern formed by said protrusions is discontinuous along a perimeter of said area to form air escape and entry channels.
6 . The heat sink of claim 5 , wherein said pattern is comprised of zigzagging columns of directly connected protrusions.
7 . The heat sink of claim 1 , wherein said heat source is a photovoltaic device.
8 . The heat sink of claim 7 , wherein when said photovoltaic device is in a module, and said module is tested by a test known as UL 1703 Temperature Cycling test for Flat Plate Photovoltaic Modules and Panels, a stress caused by said test does not induce fracture in said photovoltaic device.
9 . The heat sink of claim 7 , further comprising at least one intervening layer configured to be interspersed between said photovoltaic device and said surfaces.
10 . The heat sink of claim 8 , wherein one of said intervening layers is integrated with said surfaces during a manufacturing stage.
11 . The heat sink of claim 1 , wherein a set of said protrusions are interconnected by one or more connecting members.
12 . The heat sink of claim 11 , wherein said connecting members are flexible.
13 . The heat sink of claim 12 , wherein:
said surfaces are within a single plane; and
a cross-section of each of said protrusions decreases monotonically with the distance of said cross-section from said plane.
14 . The heat sink of claim 13 , wherein said protrusions are hollow.
15 . The heat sink of claim 1 , wherein each of said protrusions has a center to center spacing with at least one other protrusion that is less than 15 mm.
16 . The heat sink of claim 15 , wherein a set of said protrusions are interconnected by one or more connecting members.
17 . The heat sink of claim 16 , wherein said connecting members are flexible.
18 . The heat sink of claim 15 , wherein said heat source is a photovoltaic device.
19 . The heat sink of claim 18 , further comprising:
at least one intervening layer configured to be interspersed between said photovoltaic device and said surfaces;
wherein one of said intervening layers is integrated with said surfaces during a manufacturing stage.
20 . The heat sink of claim 19 wherein when said photovoltaic device is in a module, and said module is tested by a test known as UL 1703 Temperature Cycling test for Flat-Plate Photovoltaic Modules and Panels, a stress caused by said test does not induce fracture in said photovoltaic device.
21 . A method of cooling a heat source comprising the steps of:
conducting heat energy from said heat source to a plurality of protrusions on a heat sink connected to said heat source, said protrusions having surfaces that have surface areas that are in direct thermal communication with said heat source; and
convecting said heat energy from said plurality of protrusions via fluid channels between said plurality of protrusions having surfaces in direct thermal communication with said heat source; wherein
a sum of said surface areas is less than an area defined by a set of outer-most coordinates of said surfaces.
22 . The method of claim 21 , wherein said heat sink is less rigid mechanically than said heat source.
23 . The method of claim 21 , wherein a set of said protrusions are interconnected by one or more flexible connecting members.
24 . The method of claim 21 , wherein said heat source is a photovoltaic device.
25 . The method of claim 24 , wherein each of said protrusions has a center to center spacing with at least one other protrusion that is less than 15 mm.
26 . A method of fabricating a heat sink comprising the steps of:
stamping a protrusion pattern on a base sheet to form a plurality of protrusions;
separating each of said protrusions from said base sheet while leaving a base portion of each of said protrusions attached to said base sheet; and
bending each of said protrusions upwardly away from a plane formed by said base sheet while a bottom portion of each of said protrusions remains attached to said base sheet.
27 . The method of claim 26 , wherein each of said protrusions is disposed on said base sheet in an offset fashion with respect to an adjacent protrusion.
28 . The method of claim 26 , wherein said heat sink is configured for direct thermal communication with a photovoltaic device.