Passive thermal management system with phase change material

1. A computing device comprising:

a heat generating component;

a heat spreader physically connected to the heat generating component, the heat spreader comprising a first outer surface and a second outer surface, the second outer surface being closer to the heat generating component than the first outer surface is to the heat generating component;

a first layer of phase change material directly on at least a first portion of the first outer surface, the second outer surface, or the first outer surface and the second outer surface of the heat spreader; and

a second layer of phase change material directly on at least a second portion of the first outer surface of the heat spreader such that the first layer and second layer are laterally adjacent to one another, wherein the first layer of phase change material and the second layer of phase change material have different melting temperatures, different latent heats of fusion, different densities, or any combination thereof.

2. The computing device of claim 1 , wherein the heat spreader comprises a phase change device.

3. The computing device of claim 1 , wherein the heat spreader comprises a solid piece of thermally conductive material.

4. The computing device of claim 1 , further comprising a phase change device positioned between the heat generating component and the heat spreader, the phase change device comprising a first surface and a second surface, the first surface of the phase change device being physically connected to the heat spreader and the second surface of the phase change device being physically connected to the heat generating device.

5. The computing device of claim 4 , wherein the heat spreader comprises a vapor chamber, and the phase change device comprises a heat pipe.

6. The computing device of claim 1 , wherein the second layer of phase change material is applied to at least a portion of the first layer.

7. The computing device of claim 1 , wherein the first layer of phase change material comprises a layer of paraffin wax including a binder.

8. The computing device of claim 1 , wherein the first portion of the first outer surface is larger than the second portion of the first outer surface.

9. The computing device of claim 1 , wherein the first layer of phase change material contacts the first outer surface and a second outer surface of the heat spreader.

10. The computing device of claim 1 ,

wherein the computing device further comprises a third layer of phase change material, and

wherein the third layer of phase change material covers at least a portion of the second outer surface of the heat spreader.

11. The computing device of claim 1 , wherein the computing device further comprises a housing, by which the heat generating component is supported, the housing comprising an inner surface, and wherein the layer of phase change material is opposite and at a distance from the inner surface of the housing.

12. A computing device comprising:

a housing;

a heat generating component supported by the housing;

a heat pipe comprising a first surface and a second surface, the second surface of the heat pipe abutting or being adjacent to the heat generating component;

a heat spreader comprising a first outer surface and a second outer surface, the heat spreader being physically connected to the heat pipe and the second outer surface of the heat spreader being closer to the first surface of the heat pipe than the first outer surface of the heat spreader is to the first surface of the heat pipe; and

a first layer of phase change material directly on at least a first portion of the first outer surface of the heat spreader; and

a second layer of phase change material directly on at least a second portion of the first outer surface of the heat spreader.

13. The computing device of claim 12 , wherein the heat generating component comprises a processor.

14. The computing device of claim 12 , wherein the heat spreader comprises a solid piece of metal or graphite.

15. The computing device of claim 12 , wherein the heat pipe is a first heat pipe,

wherein the computing device further comprises at least a second heat pipe, the second heat pipe comprising a first surface and a second surface, and

wherein the second surface of the second heat pipe is physically connected to a portion of the first surface of the first heat pipe, and the first surface of the second heat pipe abuts or is adjacent to the second surface of the heat spreader.

16. The computing device of claim 15 , wherein the first heat pipe has a length and extends in a first lengthwise direction orientation, and the second heat pipe has a length and extends in a second lengthwise direction orientation, the first lengthwise direction orientation being different than the second lengthwise direction orientation such that the first heat pipe and second heat pipe are oriented at an angle to one another.

17. The computing device of claim 12 , wherein the heat pipe comprises a central portion and three or more extensions extending away from the central portion longitudinally in coplanar directions.

18. The computing device of claim 12 , wherein the first layer of phase change material and second layer of phase change material covers the entire first outer surface of the heat spreader, and

wherein the at least one of the first layer of phase change material and the second layer of phase change material comprises a layer of paraffin wax.

19. A thermal management device comprising:

a phase change device;

a heat spreader physically attached to the phase change device, the heat spreader comprising a first outer surface and a second outer surface, the second outer surface of the heat spreader being closer to the phase change device than the first outer surface of the heat spreader is to the phase change device;

a first layer of phase change material directly contacting a first portion of the first outer surface of the heat spreader; and

a second layer of phase change material directly contacting a second portion of the first outer surface of the heat spreader,

wherein the first layer of phase change material is a different size than the second layer of phase change material such that a size of the first portion contacted by the first layer is different from a size of the second portion, the first layer of phase change material is made of a different material than the second layer of phase change material, or a combination thereof.

20. The thermal management device of claim 19 , wherein the first layer of phase change material and the second layer of phase change material have different melting temperatures.