The present invention relates to batteries and, more particularly, to temperature controlled battery pack assemblies.
Exposure to elevated temperatures can significantly reduce the effective service life of batteries, such as batteries used to provide emergency backup or auxiliary power to electronic equipment that enables critical functions (e.g., computer systems, telecommunications systems and medical equipment). Information technology (IT) equipment is commonly housed in a controlled datacenter environment. While the datacenter environment has traditionally been a relatively cool environment by design, there is a trend toward higher datacenter temperatures in an effort to reduce cooling requirements and improve operating efficiency. This trend is enabled by IT equipment that is more tolerant to higher temperatures. Also, there is a shift to shorter backup times as datacenters migrate to cloud computing environments. The shorter backup times enable backup batteries to be dispersed among IT equipment on the datacenter floor. As a result, a continued rise in datacenter temperatures may adversely impact battery life in datacenters.
According to embodiments of the present invention, a temperature controlled battery pack assembly includes a housing defining a battery chamber and including thermal insulation surrounding at least a portion of the battery chamber. At least one battery cell is contained in the battery chamber. The thermal insulation inhibits thermal transfer between the at least one battery cell and the surrounding environment. A thermal bridge conductor is disposed in the battery chamber and engages the at least one battery cell. The battery pack assembly further includes a thermoelectric cooler device having an inner surface and an outer surface. The thermoelectric cooler device is operable to actively transfer heat between the inner and outer surfaces using the Peltier effect. A heat sink device is in contact with or connected to the outer surface to enable thermal conduction between the outer surface and the heat sink device. The battery pack assembly includes a fan operable to force a flow of a heat transfer fluid across the heat sink device and into the environment to enable convective heat transfer between the heat sink device and the environment. The thermal bridge conductor is in contact with or connected to the inner surface to enable thermal conduction between the inner surface and the thermal bridge conductor.
In some embodiments, the at least one battery cell includes a plurality of battery cells.
According to some embodiments, the thermoelectric cooler device is operable to actively transfer heat from the inner surface to the outer surface using the Peltier effect to thereby cool the at least one battery cell.
The battery pack assembly may include a thermal conduction block in contact with each of the thermal bridge conductor and the inner surface to conduct heat therebetween.
The battery pack assembly may include a thermally insulative spacer between the thermal bridge conductor and the heat sink device.
In some embodiments, the housing includes an outer shell surrounding the thermal insulation, the at least one battery, the thermoelectric cooler device, the heat sink device and the fan to form a modular unit. According to some embodiments, the housing includes an inlet port and an outlet port and the fan, when operated, draws the heat transfer fluid into the housing through the inlet port, forces the heat transfer fluid across the heat sink device, and forces the heat transfer fluid out of the housing through the exit port.
In some embodiments, the at least one battery cell includes a plurality of battery cells, and the thermal bridge conductor includes a base wall supporting the plurality of battery cells and upstanding side walls integral with the base wall, the base wall and the side walls collectively defining a battery cell tray.
The battery pack assembly may include a thermoelectric cooler device controller including a control circuit operative to programmatically control a flow of electrical current to the thermoelectric cooler device and thereby control a rate of heat transfer between the at least one battery cell and the environment. In some embodiments, the control circuit is operative to control the flow of electrical current to the thermoelectric cooler device as a function of a temperature of the at least one battery cell.
According to some embodiments, the battery chamber is sealed.
In some embodiments, the housing is a modular case.
According to method embodiments of the present invention, a method for regulating a temperature of at least one battery cell includes providing a temperature controlled battery pack assembly including: a housing defining a battery chamber and including thermal insulation surrounding at least a portion of the battery chamber; at least one battery cell contained in the battery chamber, wherein the thermal insulation inhibits thermal transfer between the at least one battery cell and the surrounding environment; a thermal bridge conductor disposed in the battery chamber and engaging the at least one battery cell; a thermoelectric cooler device having an inner surface and an outer surface and being operable to actively transfer heat between the inner and outer surfaces using the Peltier effect; a heat sink device in contact with or connected to the outer surface to enable thermal conduction between the outer surface and the heat sink device; and a fan. The thermal bridge conductor is in contact with or connected to the inner surface to enable thermal conduction between the inner surface and the thermal bridge conductor. The method further includes: operating the thermoelectric cooler device to actively transfer heat between the interior and exterior surfaces using the Peltier effect; and operating the fan to force a flow of a heat transfer fluid across the heat sink device and into the environment to enable convective heat transfer between the heat sink device and the environment.
According to some embodiments, the method includes programmatically controlling a flow of electrical current to the thermoelectric cooler device and thereby controlling a rate of heat transfer between the at least one battery cell and the environment. In some embodiments, programmatically controlling the flow of electrical current to the thermoelectric cooler device includes controlling the flow of electrical current to the thermoelectric cooler device as a function of a temperature of the at least one battery cell.
Further features, advantages and details of the present invention will be appreciated by those of ordinary skill in the art from a reading of the figures and the detailed description of the preferred embodiments that follow, such description being merely illustrative of the present invention.
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which illustrative embodiments of the invention are shown. In the drawings, the relative sizes of regions or features may be exaggerated for clarity. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art.
It will be understood that when an element is referred to as being “coupled” or “connected” to another element, it can be directly coupled or connected to the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly coupled” or “directly connected” to another element, there are no intervening elements present. Like numbers refer to like elements throughout. As used herein the term “and/or” includes any and all combinations of one or more of the associated listed items.
In addition, spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the exemplary term “under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. As used herein the expression “and/or” includes any and all combinations of one or more of the associated listed items.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein.
The term “programmatically” refers to operations directed and/or carried out electronically by computer modules, code, instructions and/or circuits.
The effective service life of a battery such as an auxiliary or emergency backup power battery in an uninterruptible power supply (UPS) system may depend significantly on the ambient temperature in the battery's environment. To improve battery life, the ambient temperature should be maintained in a prescribed range, typically between about 20 and 25° C. Historically, it has been a commonplace to provide cooling for electronic components in equipment. Various techniques have been employed to cool heat-producing components, such as venting, enclosure fans, heat sinks and heat pipes, for example. These devices all have a common problem, namely, they cannot reduce the temperature about the battery to below ambient temperature. As discussed above, ambient temperatures within datacenters are tending to rise to temperatures well in excess of the preferred range for enhancing battery life, so that it is now desirable to provide a mechanism to provide supplemental cooling for batteries in datacenters. The above-mentioned traditional approaches to cooling electronic equipment fail to improve the local battery ambient temperature (i.e., the ambient temperature immediately about the battery), and therefore fail to improve battery life.
Thus, there exists a need or desire to reduce the local battery ambient temperature to a temperature below the room temperature proximate or local to the battery (referred to herein as the room or datacenter ambient temperature). Known systems for cooling to below room ambient temperature include vapor phase refrigeration and Peltier cooling, for example. Vapor phase refrigeration can be relatively expensive or complex to construct or maintain. Peltier cooling provides certain design and implementation advantages (e.g., small in size and convenient), but Peltier cooling devices are typically inefficient.
In accordance with embodiments of the present invention, a battery pack assembly is configured to actively cool the local battery ambient temperature using a thermoelectric cooler (TEC) device (e.g., a Peltier device). The battery pack assembly may be configured to more efficiently utilize the TEC device. The battery pack assembly can maintain the local battery ambient temperature with a prescribed range below the room ambient temperature without consuming undue power to operate the TEC device.
With reference to
The load equipment 20 and the battery pack assembly 100 are each electrically connected to the UPS circuit 24. The load equipment 20 may be, under normal operation, supplied by a line power supply 22. The line power can be routed to the load equipment 20 under the control of and/or via the power supply management controller 24. In the event of a loss of power from the line power supply 22, the power supply management controller 24 can direct power from the battery pack assembly 100 to the load equipment 20 to provide a backup or emergency power supply that enables continued operation of the load equipment 20. The battery pack assembly 100 and the power supply management controller 24 may function in the same manner as known UPSs, for example, and it will be appreciated that the battery pack assembly 100 can be used in other configurations and applications.
The load equipment 20 may be, for example, electronic equipment such as a computer server. The datacenter room 5 may be, for example, a room dedicated, at least in part, to the storage and protection of such equipment. The load equipment 20 may include IT equipment.
Turning to the battery pack assembly 100 in more detail and with reference to
The battery set 110 (
The case 120 (
The insulation 124 defines the battery subchamber 104A. The insulation 124 and the outer shell 122 collectively define a heat sink subchamber 104B within the outer shell 122 and opposite the battery subchamber 104A. The heat sink subchamber 104B and the battery subchamber 104A are connected by an exchange opening 125 defined in one end of the insulation 124.
The shell 122 may be formed of any suitable material, such as a metal or polymeric material. According to some embodiments, the shell 122 is formed of polyvinyl chloride (PVC). According to some embodiments, the shell 122 has a thickness T1 (
The insulation 124 may be formed of any suitable material, such as a ceramic or polymeric thermal insulation material. According to some embodiments, the insulation 124 is formed of a polymeric foam such as a closed cell urethane foam. According to some embodiments, the insulation 124 has an R-value of at least 2. In some embodiments, the insulation 124 has a thickness T2 (
The heat pump system 102 (
The base plate 130 (
The support bracket 140 (
The thermal conductor block 150 (
The TEC module 160 (
According to some embodiments, for example as illustrated, the TEC module 160 includes parallel opposed inner and outer heat transfer plates 162 and 164 having opposed inner and outer engagement surfaces 162A and 164A, respectively. A Peltier layer 166 is sandwiched or interposed between the plates 162, 164. The TEC module 160 may be packaged in a pouch or cover (not shown) for protection from moisture, dust or impact.
The heat transfer plates 162, 164 are thermally conductive and typically electrically insulative. Suitable materials for the heat transfer plates 162, 164 may include a ceramic such as aluminum oxide.
The Peltier layer 166 may comprise a thermopile including a plurality of n- and p-type thermoelectric legs 166A that are thermally in parallel and connected electrically in series via electrical conductors 166B. Electrical leads 168A, 168B electrically connect the electrical conductors 166B to a direct current (DC) electrical source. The thermoelectric legs 166A may include a matrix of thermoelectric elements (e.g., pellets) such as a semiconductor (e.g., bismuth telluride). The Peltier layer 166 may be soldered to the heat transfer plates 162, 164.
Suitable constructions for the TEC module 160 will be known to those of skill in the art in view of the disclosure herein and it will be appreciated that the TEC module 160 can be configured differently than illustrated herein. Suitable TEC modules for use as the TEC module 160 may include the TEC 12705 thermoelectric cooler.
The heat sink device 170 (
The pad 176 (
The fan 178 (
With reference to
The battery pack assembly 100 may be assembled as follows. The conductor block 150 is seated in the seat 146 of the support bracket 140 and secured in place by the fasteners 106B through the holes 147B and 157A as best seen in
The foregoing subassembly can in turn be mounted on the end wall 134A of the base plate 130 by fastening the conductor block 150 tightly to the end wall 134A using the screws 106A through the holes 157B and the holes 135 in the end wall 134A as shown in
Referring the
The base plate 130 with the aforedescribed subassembly of the components 140, 150, 160, 170, 176 is placed in the lower insulation member 124A (
The outer shell members 122A are installed about the insulation members 124 to enclose the insulation members 124 and to form the heat sink subchamber 104B housing the heat sink device 170. The fan 178 can be separately mounted in the subchamber 104B to direct ambient air onto the fins 174, for example. The bands 123 are installed over the outer shell members 122.
In use, the battery pack assembly 100 is connected to the system 10 as described above with reference to
In order to improve the service life of the battery cells 112, it is desirable to maintain the local ambient battery temperature of the battery cells 112 in a prescribed target temperature range. According to some embodiments, the target temperature range is in the range of from about 20 to 25° C. In the event that the room ambient temperature exceeds the target temperature, the room ambient temperature will tend to heat the battery cells 112.
The heat pump system 102 is operated in order to fully or partially compensate for the relatively elevated room ambient temperature and thereby maintain the battery cells 112 in or proximate the target temperature range and at a temperature below the room ambient temperature. According to some embodiments, the heat pump system 102 is programmatically and automatically controlled by the heat pump controller 190.
More particularly, the heat pump controller 190 applies a voltage across the TEC module 160 so that the electrical current supplied to the Peltier layer 166 generates a temperature differential between the plates 162, 164, cools the inner plate 162 and heats the outer plate 164. The cooling of the inner plate 162 in turn cools the conductor block 150 which in turn cools the base plate 130, inducing conductive heat transfer from the battery cells 112 to the heat sink device 170 via the TEC module 160. The fan 178 is operated to draw a flow F (
The heat pump controller 190 can control operation of the TEC module 160 based on the temperature as detected by the temperature sensor 194. The heat pump controller 190 may provide current to the TEC module 160 when the detected temperature in the battery chamber 104A exceeds the target temperature range, and may cease providing current when the detected temperature is within the target temperature range. Thus, the TEC module 160 may be cycled as needed to keep the battery chamber temperature in the desired target range. The fan 178 likewise may be actuated and deactuated based on the detected temperature (e.g., by the heat pump controller 190), or may be run continuously or periodically independently of the detected temperature.
In the foregoing manner, the temperature of the battery chamber 104A and the battery cells 112 can be cooled to and maintained at a temperature or temperatures below room ambient. This can extend the battery service life in applications or environments where the room ambient temperature is significantly higher than the optimal battery temperature. The insulation 124 insulates the battery chamber 104A from the room ambient to reduce the degree and duration of cooling required by the heat pump system 102, improving system operating efficiency. According to some embodiments, the battery chamber 104A is substantially sealed from the room ambient air to prevent or minimize convective heat transfer from the room ambient to the battery cells 112.
The battery chamber 104A may be configured to be of relatively low volume in order to provide a low surface area for unintended heat transfer between the battery cells 112 and the room, thereby permitting the effective use of a TEC module 160 having low output or efficiency.
By way of example, if the battery chamber 104A is maintained at 20° C., the room ambient is 30° C. (for an effective temperature difference of 10° C. or 10K), and the battery chamber 104A is insulated to R-2 (R=2.0 m2K/W), heat energy will be transferred to the battery chamber 104A through the case 120 at a rate of E=10K/2K*m2/W=5 watts for each square meter of surface area. This low rate of loss is within the range of heat transfer that can be generated by a low cost Peltier cooler device.
The spatially distributed base plate 130 can provide a more uniform temperature distribution across the battery set 110 and facilitate more rapid and efficient heat transfer to the heat sink device 170.
While the battery pack assembly 100 has been shown and described as including a battery set 110 including a plurality of battery cells 112, in some embodiments, only a single cell may be provided in the battery pack assembly.
While the thermal bridge conductor has been shown and described as tray-shaped base plate 130, according to some embodiments, other configurations may be employed. For example, the side walls 134A, 134B may be eliminated and/or further thermally conductive walls may be provided that extend up between and engage the battery cells 112. Other configurations for the thermal bridge conductor may include an open lattice configuration and/or a configuration wherein one or more thermal bridge conductor members extend both above and below the battery cells 112.
With reference to
While the battery pack assembly 100 as illustrated and described constitutes a relatively compact, modular, standalone battery pack assembly unit, according to some embodiments, the case is integrated into an electronic component. For example, an electronic component (e.g., a computer server) may include an integral compartment that is insulated, vented and provided with a heat pump system corresponding to the heat pump system 102. The battery cell or cells are enclosed in the insulated compartment and cooled as described herein.
The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although a few exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention. Therefore, it is to be understood that the foregoing is illustrative of the present invention and is not to be construed as limited to the specific embodiments disclosed, and that modifications to the disclosed embodiments, as well as other embodiments, are intended to be included within the scope of the invention.