Patent Application
20250212361
Computing devices generate heat as a byproduct of computational workloads. The heat is removed from the devices to enable processing to continue without incurring damage to constituent electronic components such as semiconductors. A coldplate receives heat from the electronic components to efficiently remove heat from the computing device and dissipate it to a surrounding environment.
A liquid-cooling assembly for solid state drives (SSDs) includes rack-mounted liquid-cooled coldplates that are placed in intimate thermal contact with heat spreaders on the SSDs using a dry-contact interface when the SSDs are mounted in an electronic equipment rack. A coldplate is provided in each SSD-receiving slot in the rack so that individual SSDs can be removed and replaced in “hot swapping” scenarios. The dry-contact interface between the SSD heat spreader and coldplate ensures that the SSD can be readily hot-swapped without affecting the cooling of the other SSDs in the rack.
The heat spreader in an SSD is in thermal contact with heat-producing semiconductors in the SSD. The heat spreader includes an external thermal interface in contact with mating surfaces of the coldplate to create a thermal path from the semiconductors to a liquid-cooling system. The mating surfaces of the coldplate include a dry-contact thermal interface material (TIM) to enhance the heat transfer from the SSD heat spreader.
The SSD includes a user-operable latching mechanism that functions to push against a fixed feature of the rack slot. As the SSD is slid into place, a technician manipulates the latch to firmly seat the SSD's power and data connector into a mating connector in the rack to ensure good electrical continuity while fixedly locating the SSD in position. When the SSD is seated, the coldplate is in position to contact the SSD heat spreader through the dry-contact interface to ensure effective thermal performance of the SSD using liquid-cooling.
This Summary is provided to introduce a selection of concepts in a simplified form that are further described below in the Detailed Description. This Summary is not intended to identify key features or essential features of the claimed subject matter, nor is it intended to be used as an aid in determining the scope of the claimed subject matter. Furthermore, the claimed subject matter is not limited to implementations that solve any or all disadvantages noted in any part of this disclosure.
Like reference numerals indicate like elements in the drawings. Elements are not drawn to scale in the drawings.
Solid state drives (SSDs) have historically not been liquid-cooled because air-cooling typically provides satisfactory performance. However, as semiconductors increase in geometry and total power increases, the higher heat flux that is caused makes computing devices more difficult to cool. Operators of large datacenters are increasingly moving to all liquid-cooling and have an interest in applying liquid-cooling to SSDs to gain economies of scale while avoiding the logistical complexities in simultaneously managing both air-and liquid-cooling paradigms in hybrid deployments.
The present hot-swappable liquid-cooled SSDs provide highly effective thermal management for the SSDs using compact components to enable increased SSD packing density within equipment racks. The utilization of dry-contact interfaces between the SSDs and the liquid-cooling components not only provides ease of ongoing operations such as hot-swapping, but is also readily integrated into existing liquid-cooling systems.
In a first illustrative embodiment, a liquid-cooled coldplate is configured to thermally interface with a top-mounted externally-exposed heat spreader bar that is incorporated into a heat spreader system in an SSD. In a second illustrative embodiment, a liquid-cooled coldplate is configured to thermally interface with an SSD heat spreader system over broad area surfaces.
Turning now to the drawings,
SSDs are typically mounted in an electronic equipment chassis in typical datacenter applications. Chassis are alternatively commonly referred to as “racks” or “bays” and typically configured using standardized sizing, for example, a 19 in. (482.6 mm) width between mounting rails, as defined by the Electronic Industries Alliance (EIA). A computer server rack is commonly 42 to 48U tall (1U is equal to 44.5 mm (1.75 in.)) and can have varying depth. Another rack architecture that is in common use in datacenters and adaptable to use the present principles is the Open Rack described by the Open Computer Project. Open Rack units are commonly referred to as OpenU or OU have 21 in. (538 mm) rail spacing with a 1OU height of 48 mm (1.89 inches).
The slot implementation can vary by the type of component being rack-mounted, rack manufacturer, and other factors.
SSD 100 includes a latching mechanism 900 for installing the SSD in an electronic equipment rack as shown in the partially phantom views of the SSD in
As shown in
With continued rotational motion of the lever 905, the catch 910 will engage with a recessed area of the lever and hold it closed.
The active components 1305, as in this illustrative example, can have different stand-off heights from the surface of the printed circuit board 1310. In addition, the components may have different heat outputs. The varying heights can cause difficulty to provide good thermal contact between them and a flat and rigid case (indicated by the dashed line 1315). The different active component size is typically dealt with by the use of thick thermal gap pads. While effective in some applications, the gap pads, case, and air-cooling fins are space-consuming and can make the SSD relatively thick (i.e., in the “x” direction). The thickness is increased even further in SSD designs in which air-cooling fins are utilized on both sides. It may be appreciated that increasing SSD thickness results in less SSD packing density which is generally undesirable for datacenter operators.
The heat spreader assembly 1500 includes planar heat spreader plates 1505 that are thermally coupled with a heat spreader bar 1510 which provides2 the external surfaces that function as a thermal interface contacting the coldplate. The heat spreader assembly is typically fabricated from materials having high thermal conductivity such as copper, aluminum, or other suitable metallic, non-metallic, and/or composite materials. The heat spreader bar has a peaked shape, however the shape shown is illustrative and not intended to be limiting. Other shapes and form factors incorporating the present principles are usable to meet the needs of a particular implementation. As shown in
Returning to
The heat spreader bar 1510 functions as a thermal hub that is located at the top of the heat spreader plates. The location at the top helps to optimize heat transfer to the coldplate because the heat-saturated vapor flows upward to the colder condenser sections of the plates.
TIM 1610 is optionally utilized on portions or all of the exterior broad area surfaces of the heat spreader plates 1505. For this application, the TIM is selected from various thermally conductive dry-contact materials including, for example and without limitation, films, tapes, pads, and/or foils which may be constructed from silicon, graphite, or phase-change materials. Dry-contact TIM is also optionally disposed (not shown) on the outwardly facing surfaces of the heat spreader bar 1510.
As discussed above, the active components of the SSD can have varying stand-off heights. In some implementations of the present principles, the heat spreader assembly is configurable to use multi-segment heat spreader plates to accommodate components of varying heights without having to utilize thick gap pads. Alternatively, a unitary (i.e., one-piece) heat spreader plate can be utilized to interface with the varying-height internal active components that are disposed on one side of the printed circuit board. In this embodiment, the inward-facing surfaces of a heat spreader plate (i.e., surfaces facing the components) are staggered with varying thicknesses while the outward-facing surfaces (i.e., externally exposed surfaces) of the plate are provided with a planar configuration.
SSD 1700 may be utilized in datacenter applications in which liquid-cooling systems are adopted.
The liquid-cooling system 2515 includes various components that are utilized in common rack cooling scenarios in datacenters including, for example and without limitation, pumps, filters, hoses, fans, heat exchangers, fluid reservoirs, valves, controls, and the like. The liquid-cooling system is implementable as a standalone system or may be incorporated, in whole or part, into one or more equipment racks. The liquid-cooling distribution system 2510 is configured to provide liquid-cooling to individual rack-mounted components, including the SSDs and computer servers in this illustrative example.
The hoses are configurable as dry break hoses, as shown in
In another illustrative embodiment, the dry-contact gap pad 2905 comprises a viscous TIM that is held between layers of polymer film. The viscous TIM can be selected, for example and not by way of limitation, from one of phase change material, thermal grease, thermal paste, thermal putty, thermal gel, graphite-based material, silicone-based material, or metal-based material. The utilization of polymer film keeps the interface between mating heat spreader and coldplate components dry while still providing reasonable wetting characteristics and good thermal conductivity. The polymer film also acts as a wear surface as it comes into physical contact with the SSD heat spreader.
The coldplate can be fabricated from various thermally conductive materials such as copper, aluminum, or other suitable metallic, non-metallic, and/or composite materials. For example, the coldplate can be fabricated from billet copper and machined to form the correct outer shape using one or multiple subcomponents that are assembled using adhesives or fasteners and/or processes such as welding, etc. Internal passages can be formed using a suitable material removal process such as drilling or milling. Alternative fabrication processes comprise extrusion, metal casting, pressing, stamping, molding, etc. For example, the internal passages 3205 may be fabricated using copper tubing and assembled to an extruded shell that forms the contacting surfaces with an SSD.
The shape of the coldplate 2600 is peaked, as shown in the front view of
The range of movement of the coldplate 2600 can vary by application and is not required to match the ranges shown in the drawings which are illustrative. In some applications the range of movement and differences between coldplate positions before, during, and after SSD installation are relatively small. Generally, as the SSD slides into its slot during installation, the coldplate is first positioned (i.e., in an open position) to provide sufficient clearance to minimize sliding frictional forces between the coldplate and the heat spreader bar to facilitate ease of installation. Minimization of friction also reduces wear of the dry-contact gap pad 2905. When the SSD is seated in the slot, the coldplate hingedly rotates from the clearance position to a second position (i.e., to a closed position) providing zero clearance, or near-zero/minimal clearance, so that the coldplate and heat spreader bar are in intimate thermal contact to maximize heat transfer from the SSD to the liquid-cooling system.
In some embodiments, the hinge is spring-biased so that the static or resting position of the coldplate 2600 is in, or near, the non-clearance position prior to SSD installation. The spring biasing provides some downward (i.e., in the negative “y” direction) clamping pressure on the interface between the coldplate 2600 and the heat spreader bar 1510 when SSD 1700 is in its installed/seated position in the slot. Such downwardly-directed clamping force from the coldplate may enhance the quality of the thermal contact with the heat spreader bar.
When a spring-biased mounting mechanism is used for the coldplate, as shown in
A catch 3705 uses a cammed surface that interfaces with moveable pin 3710 that is spring-biased to push the pin towards the catch. When the coldplate 3700 is moved into its open position by rotating about the hinge 3715, the pin pushes against the cam surface of the catch to hold the coldplate up against the torque provided (in a counter-clockwise direction in the drawing) from a biasing spring (not shown) in the hinge. After the SSD is seated, the technician rotates the coldplate 3700 downwards to force the pin off the cam of the catch. Once the catch is released, the spring force from the hinge applies clamping pressure to the SSD heat spreader 1510 from the coldplate, as shown in
In some embodiments, the coldplate 2600 is fixedly located within the rack slot in a non-clearance/closed position with respect to the SSD 1700, or in a position having minimal clearance, and is not configured for substantial movement. Alternatively, the coldplate is moveably mounted in the rack to provide slight movement of the coldplate, for example using mounting fixtures having some degree of flex. In both such cases, positive thermal contact between the coldplate and the heat spreader bar is maintained for the installed SSD. The dry-contact gap pad 2905 (
Some frictional force at the interface between the heat spreader bar and coldplate can be expected as the surfaces slide past each other during SSD installation. The increased frictional forces manifested in static/non-moveable coldplate embodiments may cause some additional effort for the technician when installing the SSD. Friction between the coldplate and heat spreader bar can also increase wear of the dry-contact gap pad 2905 (
Other suitable parallel-movement mechanisms include, for example and without limitation, multi-bar mechanical linkages such as four-bar and six-bar linkages. The mechanisms can be spring-biased in some cases to put coldplate 2600 into a non-clearance/closed resting position.
The coldplate and SSD are configurable to use various different latching arrangements to facilitate the positioning of the coldplate during SSD installation. Such latching can further ensure establishment of positive thermal contact between the coldplate and the SSD heat spreader bar when the SSD is fully seated in position within its slot in the equipment rack 2305.
For a given SSD design, the latching mechanism may be implemented by itself or in combination with hinge springs, as discussed above, to provide clamping pressure on the interface between the heat spreader bar and coldplate when the SSD is seated in the slot. When the coldplate is in its non-clearance position relative to the mounted SSD, and lever 905 is in its closed position, a latch finger 4205 is extended into a latch finger receiver 4210 that is attached to the end of the coldplate, as shown in the enlarged view in
As shown in the partially phantom views of the coldplate 4610 in
When the SSD is fully seated in the rack 2305, as shown in
The coldplate 5000 is embodied using two separate components 5015 and 5020 that are located on either side of the SSD to interface with the broad area surfaces of the heat spreaders in the SSD (the right-side heat spreader is indicated by the dashed line 5025) and the heat spreader bar 5010. Each component is liquid-cooled in a similar arrangement as with coldplate 2600 (
The double-sided coldplate 5000 is alternatively mounted in the rack to enable hinged or parallel movement with respect to the SSD 5005 to facilitate SSD seating in the rack. In an alternative arrangement, the coldplate is fixedly-located in the rack. In this case, the dry-contact gap pads can be configured with increased thickness, and/or use a film layer with low-friction characteristics, to minimize sliding friction with the SSD during installation.
In alternative arrangements, one or both components 5015 and 5020 of the double-sided coldplate 5000 are fixedly-located within the rack 2305. The SSD 5005 is slideably installed in the rack past the fixed components of the coldplate. As with the first embodiment of the coldplate, the dry-contact gap pads are configurable to minimize sliding friction and wear, as discussed above.
Various exemplary embodiments of the present hot-swappable liquid-cooled solid state drive are now presented by way of illustration and not as an exhaustive list of all embodiments. An example includes a liquid-cooling assembly providing liquid-cooling for a rack-mountable heat-producing electronic component, comprising: a rack providing receiving slots for each of a plurality of slideably removably mountable heat-producing electronic components, each of the electronic components having a heat spreader and one or more component-mounted connectors for power and data, the rack providing operating interfaces to each mounted electronic component via corresponding rack-mounted connectors for power and data, the rack further including a fluid distribution system having an interface to a liquid-cooling system; a liquid-cooled coldplate mounted in the rack, the coldplate having a component-contacting surface; and fluid couplers disposed on the coldplate connecting the coldplate to the fluid distribution system, wherein mounting of an electronic component in the rack comprises respective component-mounted and rack-mounted connectors being mechanically and electrically engaged to complete power and data circuits therethrough, and wherein the component-contacting surfaces of the coldplate are in intimate thermal contact with the heat spreader of the mounted electronic component to provide a thermal conduction path from the mounted electronic component to the liquid-cooling system.
In another example, the liquid-cooling assembly further comprises one or more dry-contact gap pads disposed on component-contacting surfaces of the coldplate. In another example, the dry-contact gap pad comprises a viscous thermal interface material (TIM) comprising one of phase change material, thermal grease, thermal paste, thermal putty, thermal gel, graphite-based material, silicone-based material, or metal-based material, in which the viscous TIM is captured by one or more layers of flexible polymer film. In another example, the fluid couplers comprise dry break fittings. In another example, the component-contacting surfaces of the coldplate are shaped to align the electronic component within a corresponding receiving slot of the rack. In another example, the coldplate is moveably mounted in the rack, the moveable mounting providing at least two positions for the coldplate in the rack, a first position of the coldplate providing spatial clearance between the component-contacting surfaces of the coldplate and the heat spreader of the electronic component during slidable motion of the electronic component in a corresponding receiving slot of the rack to effectuate mounting, and a second position of the coldplate providing intimate thermal contact of the component-contacting surfaces with the heat spreader of the electronic component when mounted. In another example, the coldplate is hingedly-mounted in the rack. In another example, the coldplate moves through the first and second positions based on motion of the electronic component in the receiving slot of the rack, such that the coldplate moves from the first position to the second position responsively to the electronic component being seated in the receiving slot and a respective component-mounted connector being electrically mated with a corresponding rack-mounted connector. In another example, the coldplate is spring-biased in the second position. In another example, the coldplate includes a linking mechanism that fixedly locates the coldplate to a predetermined location of the electronic component within the receiving slot of the rack. In another example, the electronic component comprises a solid state drive (SSD).
A further example includes a solid state drive (SSD) adapted for rack-mounting in an electronic equipment rack, in which the SSD is configured for slideable mounting within an SSD-receiving volume in the rack, the SSD comprising: a printed circuit board; a plurality of heat-producing semiconductors disposed on the printed circuit board, the semiconductors including NAND flash memory; a heat spreader, the heat spreader being in thermal contact with one or more of the heat-producing semiconductors, the heat spreader including an externally-facing thermal interface; a connector providing electrical connections to the printed circuit board and having a mateable portion for removable engagement with a corresponding rack-mounted connector; and a user-operable latching mechanism that is operable to apply force to an opposing surface in the rack to cause sliding motion of the SSD within the rack to seat the mateable portion of the connector with the rack-mounted connector to establish power and data circuits to the printed circuit board, wherein the thermal interface of the heat spreader provides a thermal conduction path for the heat-producing semiconductors to an external liquid-cooled coldplate that is disposed in the rack when the corresponding connectors of the SSD and rack are seated.
In another example, the SSD further comprises a thermal interface material (TIM) disposed between the heat-producing semiconductors and the heat spreader. In another example, the heat spreader comprises multiple discrete components, different components adapted to interface with heat-producing semiconductors having different stand-off heights with respect to the printed circuit board. In another example, the plurality of heat-producing semiconductors is disposed across both sides of the printed circuit board and the heat spreader comprises multiple components distributed on both sides of the printed circuit board over the heat-producing semiconductors. In another example, the heat spreader comprises a vapor chamber. In another example, the user-operable latching mechanism is further operable to releasably fasten the liquid-cooled coldplate to the SSD. In another example, the user-operable latching mechanism is operable to simultaneously seat the mateable portion of the connector with the rack-mounted connector and fasten the SSD to the liquid-cooled coldplate in one motion of the user-operable latching mechanism. In another example, the heat spreader encloses the printed circuit board and heat-producing semiconductors, and the SSD has a form factor for slideable motion relative to surfaces forming an SSD-receiving volume in the rack, wherein the form factor complies with specifications promulgated by the EDSFF (Enterprise and Datacenter Standard Form Factor).
A further example includes a liquid-cooling system, comprising: a liquid-cooled coldplate; a rack to which the coldplate is moveably mounted, the rack providing receiving slots for each of a plurality of slideably removably mountable solid state drives (SSD), each SSD comprising: a printed circuit board; a plurality of heat-producing semiconductors disposed on the printed circuit board, the semiconductors including NAND flash memory; a connector having a mateable portion for removable engagement with a corresponding rack-mounted connector, in which the mateable portion is exposed externally; a heat spreader, the heat spreader being in thermal contact with one or more of the heat-producing semiconductors, the heat spreader including a thermal interface that is at least partially externally exposed from the SSD; and a user-operable latching mechanism that is operable to apply force to the SSD-receiving slot to cause sliding motion of the SSD within the SSD-receiving slot to seat the mateable portion of the connector with the rack-mounted connector to establish power and data circuits to the printed circuit board, wherein the thermal interface of the heat spreader provides a thermal conduction path for the heat-producing semiconductors to the coldplate when the corresponding connectors of the SSD and rack are seated; a fluid distribution system having an interface to a liquid-cooling system; and fluid couplers disposed on the coldplate connecting the coldplate to the fluid distribution system.
Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.
