Battery thermal management system with passive battery pack cooling

According to one embodiment, a battery module includes an output connector, several battery cells that are coupled to the output connector and are at least partially submerged within a liquid coolant. The battery cells are configured to provide battery energy to a load via the output connector and are configured to draw power from an external power supply to charge the battery cells via the output connector. While the battery cells provide the battery energy or draw power, the battery cells generate heat that is transferred into the liquid coolant, thereby causing at least some of the liquid coolant to turn into vapor extracting the heat. The battery module also includes a condenser that is positioned above the battery cells and is configured to condense the vapor back into liquid coolant.

FIELD

Embodiments of the present disclosure relate generally to a battery thermal management system that passively cools battery packs. More particularly, embodiments of the disclosure relate to a battery thermal management system that utilizes phase change of fluid to cool a battery pack.

BACKGROUND

Lithium-ion batteries are commonly used in the vehicle industry, for example, electric vehicles (EVs) and plug-in hybrids. Lithium-ion battery packs for electric vehicles are designed for vehicle specific requirements and usage. Lithium-ion batteries, however, are also becoming popular for IT equipment and data center as an energy storage unit that is replacing UPS systems and attracting much attention from the industry.

Large clusters of computer servers can be kept in dedicated facilities, often in a rack enclosure. The servers can be used in support of the data center industry. Use of a battery backup unit (BBU) in place of traditional solutions, such as lead-acid based Uninterruptible Power Supply (UPS) systems, has grown in popularity. One result of the BBU's new role in the data center space is the relocation of the BBU from a centralized battery room to a data center IT room. Thermal environment (e.g., temperature) in the data center is generally managed and operated based on specifications and requirements of the servers, not batteries and therefore may not be optimized for BBU use.

In contrast, in the case of a BBU, the battery provides power only when backup power is needed (e.g., there is a power outage to the data center). When backup power is no longer needed (e.g., grid power is restored to the data center), the BBU is recharged. Thus, a unique problem in the BBU application is that thermal management or cooling will be active only during limited times: e.g., discharging during a power outage and charging after power is restored. Therefore, a battery thermal management system is needed that self-activates during times at which the batteries charge and discharge in order to ensure that the batteries do not over heat.

In addition, a self-activating thermal management system should be fast enough to avoid thermal overshoot, which can negatively impact battery performance and battery lifetime, and evenly cool cells. Conventional battery thermal management systems used in the data center industry primarily use air cooling. These systems, however, may not evenly cool battery cells, which could result in at least some thermal overshoot. Therefore, there is a need for a self-activating thermal management system that evenly cools batteries in order to maintain battery performance.

DETAILED DESCRIPTION

Several embodiments of the disclosure with reference to the appended drawings are now explained. Whenever the shapes, relative positions and other aspects of the parts described in a given aspect are not explicitly defined, the scope of the disclosure here is not limited only to the parts shown, which are meant merely for the purpose of illustration. Also, while numerous details are set forth, it is understood that some aspects may be practiced without these details. In other instances, well-known circuits, structures, and techniques have not been shown in detail so as not to obscure the understanding of this description. Furthermore, unless the meaning is clearly to the contrary, all ranges set forth herein are deemed to be inclusive of the each range's endpoints.

According to one embodiment, a battery module includes an output connector, several battery cells that are coupled to the output connector and are at least partially submerged within a liquid coolant, and a condenser that is positioned above the battery cells. The battery cells are configured to provide battery energy to a load via the output connector and are configured to draw power from an external power supply to charge the battery cells via the connector. While the battery cells provide the battery energy or draw power, the battery cells generate heat that is transferred into the liquid coolant, thereby causing at least some of the liquid coolant to turn into a vapor. The condenser is configured to condense the vapor back into liquid coolant.

In one embodiment, the battery module includes a supply line and a return line that are both coupled to the condenser and an external cooling unit to create a heat exchanging loop for air-to-liquid heat exchange. The supply line is configured to supply cooling fluid to the condenser and the return line is configured to receiving the cooling fluid from the condenser. The battery module may also include a valve that is coupled between the supply line and the condenser or coupled between the return line and the condenser, and is configured to allow the cooling fluid to flow through the heat exchanging loop when the batter cells provide the battery energy or draw power. In one embodiment the battery module includes a supply connector is coupled to the supply line and a return connector is coupled to the supply line, where both connectors enable the battery module to be removable coupled to the lines.

In some embodiments, the battery cells, the liquid coolant, and the condenser are sealed within a container. In other embodiments, the container and the valve are enclosed within an exterior enclosure.

In one embodiment the battery module includes a pressure sensor that is configured to detect changes in pressure within the battery module, where the valve is configured to allow the cooling fluid to flow based on the changes in pressure. In another embodiment, the battery module includes a temperature sensor that is configured to detect changes in temperature of the liquid coolant, where the valve is configured to allow the cooling fluid to flow based on the changes in temperature. In some embodiments, the battery module includes a filling port, a draining port, and a liquid level sensor that is configured to detect changes in a level of liquid coolant within the battery module. In response to the level of the liquid cooling being below a threshold, the filing port is configured to allow liquid to fill the battery module. On the other hand, in response to the level of the liquid coolant being above the threshold, the draining port is configured to drain liquid coolant from the battery module.

According to another embodiment, a battery backup unit (BBU) that is configured to provide backup power includes a set of one or more battery modules, each of which may be similar to the battery module as previously described. In one embodiment, the battery module (and/or BBU) further includes a cooling unit that is separate from the battery module, where the cooling unit is a liquid-to-air heat exchanger or a liquid-to-liquid heat exchanger.

According to one embodiment, an electronic rack includes several server blades arranged in a stack, each server blade including one or more servers to provide data processing services, a power supply coupled to the server blades to provide power to operate the servers, and a BBU coupled to the server blades to provide backup power to the servers when the power supply is unable to provide power. The BBU includes a set of battery modules, each battery module is similar to the battery module as previously described. In one embodiment, the BBU is configured to connect to a cooling fluid distribution manifold that is coupled to an external cooling unit to create a heat exchanging loop for liquid-to-liquid heat exchange. In another embodiment, the cooling fluid distribution manifold includes a supply path and a return path, where each battery module's condenser is coupled to the cooling fluid distribution manifold and is part of the heat exchanging loop to allow cooling fluid to flow from the supply path, through the condenser, and back into the return path.

In one embodiment, a cooling system or a battery thermal management system for a battery module can addressed specific needs of backup power provided by a BBU in support of IT racks in a data center or IT room environment. As described, conditions and requirements of a BBU in an IT rack, data center, and/or IT room environment are different from conditions and requirements of a battery module in an electrical vehicle application. For example, thermal environments are different, and the discharging and charging cycles occur much less in the data center application scenario than in the electrical vehicle application.

Cooling systems for batteries can be critical because nominal battery performance is typically specified for working temperatures ranges of battery cells (e.g., 25° C. to 35° C.). Temperature also plays an important role with respect to battery aging. Temperatures outside of the working range may result in reduced performance and negatively impact battery health. In addition, when multiple battery cells are connected, there can be large internal differences between different cell temperatures due to multiple factors, such as cell arrangement and cooling condition variations, which can lead to different charge and discharge rates for each cell and deteriorate performance of the battery module. Importantly, if battery temperature exceeds safety thermal limits, this can cause extreme damage or harm, even catastrophic results. Thus, thermal management of battery systems are important features to consider in the design and operation of a battery because it impacts how a battery performs, the health and lifetime of the batter, and safety.

A battery thermal management system for a BBU can be self-activating by utilising phase change natural convection heat transfer. In one embodiment, the thermal management system includes a battery module that includes 1) an output connector, 2) several battery cells that are coupled to the output connector and are at least partially submerged within a liquid coolant, and 3) a condenser. The battery cells and the condenser may be located within a cell chamber (or evaporation chamber) of the battery module, where the condenser is positioned above the battery cells.

When the cells charge or discharge, thermal energy generated by one or more of the battery cells is absorbed by (or transferred into) the liquid coolant, causing the coolant to change from liquid to vapor and rise (or travel) upward towards and into the condenser, where the condenser condenses the vapor, thereby causing the vapor to change back to liquid coolant. Specifically, the condenser is coupled to a supply line and a return line, which are coupled to an external cooling unit (e.g., a liquid-to-liquid heat exchanger) to create a heat exchanging loop for air-to-liquid heat exchange of the vapor back into the liquid coolant. Once condensed, the condensed liquid coolant drops (e.g., as droplets) and returns to the cell chamber in order to be combined with liquid coolant that is still within the chamber.

In such a manner, the battery module uses natural convection to automatically and passively manage heat generated by the battery module (e.g., the battery cells contained within the battery module) by changing fluid phases, circulating fluid, and transferring thermal energy away from the battery cells only when they get hot. Specifically, heat is transferred using natural convection (fluid is circulated within and away from the condenser), while the vapor coolant and liquid coolant remain fully contained within the battery module. This not only improves cooling performance, but also reduces the possibility of having vapor and/or liquid coolant leak out of the battery module (e.g., during transit to a data center or during operation in an electronic rack), since the whole process is performed from within the module (e.g., without having the vapor travel to an external condenser).

It should be mentioned that the phrase “battery pack” may be used herein interchangeably with “battery backup unit (BBU)” and with “BBU pack”. Also, a BBU pack may include one or more battery modules (or battery systems). A battery module may include several battery cells. Other features are also described in the following examples.

FIG. 1shows a block diagram illustrating an example of a battery module according to one embodiment. Specifically, this figure shows a battery module1that includes several battery cells2, liquid coolant3, a condenser5, a supply line8, a return line9, an output connector10, and a valve7. In one embodiment, the battery module1may have any shape and configuration. For example, as illustrated, the battery module1is a rectangular box. In other embodiments, however, the battery module1may be a square or a cylinder. In some embodiments, the battery module may include one battery cell, or may include two or more battery cells that are series connected, parallel connected, or a combination. The battery cells may be of any type, such as Lithium-ion, Nickel Cadmium, etc. The output connector10(one anode and one cathode) of the battery module1are configured to couple to a load (e.g., the load may be at least one server) in order for the battery module to provide battery energy stored within the cells to the load, and is configured to couple to a power supply (or source) to charge the battery cells in the module. In one embodiment, the output connector10are configured to be removeably coupled to connectors (not shown) of the load in order to allow the battery module1to be removed and/or added (in series or in parallel) to the load.

The liquid coolant3may be any type of liquid (or fluid), such as dielectric liquid. In one embodiment, the liquid coolant3may be a single liquid or a combination of two or more liquids. In one embodiment, the coolant may be non-toxic, environmentally-friendly dielectric heat transfer fluid. In another embodiment, the coolant may have a boiling point that enables the coolant to change phase (e.g., into a gas or vapor) based on battery cell thermal requirements. Specifically, the coolant may have a boiling point below (or at) a discharging (and/or charging) temperature threshold of the battery cells (e.g., a temperature between 45° C. to 70° C.).

The condenser5may be any type of condenser that is configured to receive (or obtain) gas or vapor, and extract and transfer thermal energy away from the vapor, thereby turning the vapor back to a liquid. Although the condenser is illustrated as a rectangular box, in one embodiment the condenser may be any shape and configuration. In one embodiment, although not illustrated, the condenser may include one or more first openings that allows vapor to enter a condenser chamber that includes a condenser coil. During operation, the condenser coil condenses the vapor back to the liquid that is then dispensed back into the cell chamber12through one or more second openings (which may be the same or different than the first openings). In one embodiment, the condenser5may be a condenser coil. The condenser coil may be any type of coil, such as spiral tubes, straight tubes, etc. More about the operation of the condenser5is described herein.

Coupled to the condenser5is a supply line8that is configured to supply cooling fluid to the condenser (e.g., that will flow through the condensing coil) and a return line9that is configured to receiving the cooling fluid from the condenser. In one embodiment, the cooling fluid that is supplied by the supply line8is at a lower temperature than the cooling fluid that is received by the return line9. In one embodiment, both lines are coupled to the condenser at one end and coupled to an external cooling unit (e.g., a unit that is separate from the battery module1) at another end. The coupling of the cooling unit (e.g., unit25illustrated inFIG. 2) to the battery module1via lines8and9create a heat exchanging loop for air-to-liquid heat exchange. In one embodiment, the supply line8and return line9may be composed of any material. For instance, the lines may be composed of metal, such as copper, a polymer (e.g., a rubber), and/or plastic. In one embodiment, the lines may be composed of a flexible material, such as rubber. In another embodiment, one line (e.g., the supply line) may be composed of a different material than the other line (e.g., the return line).

As illustrated, the valve7is coupled between the condenser5and the return line9. In one embodiment, the valve may be coupled directly to the condenser5, where the return line9couples to the condenser via the valve. In another embodiment, the valve may be coupled between the condenser5and the supply line8. In some embodiments, the battery module1may include more than one valve. The valve is configured to allow cooling fluid to flow through the heat exchanging loop (e.g., from and to the cooling unit) in order to enable the condenser to condense vapor into liquid. In one embodiment, the valve is configured to allow the cooling fluid to flow when the battery cells are discharging (e.g., providing battery energy to a load) and/or charging (e.g., drawing power from a power source).

In one embodiment, the battery module illustrated in this figure provides a thermal management solution that utilizes a phase change of coolant to passively transfer heat generated by the battery cells2in order to manage an operational temperature of the cells. Specifically, during operation (e.g., discharging and/or charging), the battery cells2will produce heat that is transferred to the liquid coolant3. The temperature of the coolant may achieve (or meet) a boiling point, thereby causing some of the coolant to change phase into a vapor4(illustrated as dashed arrows). The valve is opened in order to allow cooling fluid to flow through the condenser. The vapor is condensed by the condenser5into condensed liquid coolant6, which flows downward toward and combined with the liquid coolant3in the cell chamber at a lower temperature. This cycle may repeat while (and after) operation of the battery cells in order to maintain a thermal (e.g., equilibrium) environment within the battery pack.

FIG. 2is a block diagram illustrating an example of a battery thermal management system20that includes a battery module27, a pump21, an external cooling unit25, a controller40, and one or more fans22. In one embodiment, the battery thermal management system20(or a portion thereof) may be a part of at least one BBU, as described herein. In some embodiments, a BBU may include more or less elements of the system20. For example, one BBU may include two or more battery modules that are coupled (via separate supply and return lines) to one external cooling unit (which may or may not be a part of the BBU). In one embodiment, any of the battery modules described herein may be a part of a BBU.

In this example, the battery module27includes a supply connector23that is coupled to the condenser (e.g., via an internal supply line) and is removeably coupled to the supply line8, and a return connector24that is coupled to the condenser (e.g., via an internal return line) and is removeably coupled to the return line9. Both connectors enable the battery module to be disconnected from the supply and return lines in order to remove the battery module from the heat exchanging loop, and enable the battery module to be connected to the supply and return lines in order to create a heat-exchanging loop. In one embodiment, the connectors may be any type of connectors, such as quick-connect fittings that allow for easy connection/removal of the respective lines.

Since the battery module may be removed from a heat-exchanging loop, the module may be a self-contained unit. Specifically, the module may include a container11in which the battery cells, the liquid coolant, and the condenser are sealed within. Sealing the battery module ensures that any vapor4and/or liquid coolant3remains contained therein, thereby preventing or reducing any potential leaks. In one embodiment, the sealed battery module may include at least one valve and/or pump, as described herein.

As illustrated, the pump21is coupled between the supply line and the external cooling unit25, and is configured to push cooling fluid through the heat-exchanging loop. Specifically, the pump may be any type of mechanical pump that pushes cooling fluid into the supply line in order to circulate the fluid through the system. In one embodiment, the system20may include more than one pump. In another embodiment, pump may be coupled between the return line and the external cooling unit25, and is configured to push cooling fluid into the unit25. Similar to valve7ofFIG. 1, the pump may be configured to pump (or push) fluid when the battery cells are discharging and/or charging. Specifically, the pump may be controlled to push fluid based on certain criteria. More about controlling the pump is described herein.

In this example, the pump21is located outside of the battery module in order to allow a user access to the pump without needing to open the battery module (e.g., when the module is sealed to prevent access). The user may need to access the pump requires maintenance or needs to be replaced. As a result, the pump may be removeably coupled to the supply line (or the return line) and be removeably coupled from the external cooling unit25. In another embodiment, similar to the example ofFIG. 1, the pump21may be contained within the battery module.

The external cooling unit25may be any type of cooling unit that is configured to extract thermal energy from the cooling fluid. As illustrated, the unit25may be an air-to-liquid heat exchanger that has one or more fans22that are used to disperse heat. In one embodiment, the unit25may be any type of heat exchanger, such as a liquid-to-liquid heat exchanger. In another embodiment, the battery module may be coupled to a separate coolant distribution manifold that is coupled to one or more external cooling units, as described herein.

The controller40may be a special-purpose processor such as an application-specific integrated circuit (ASIC), a general purpose microprocessor, a field-programmable gate array (FPGA), a digital signal controller, or a set of hardware logic structures (e.g., filters, arithmetic logic units, and dedicated state machines). In one embodiment, the controller may be a circuit with a combination of analog elements (e.g., resistors, capacitors, inductors, etc.) and/or digital elements (e.g., logic-based elements, such as transistors, etc.). The controller may also include memory. In one embodiment, the controller may be a part of the battery module (e.g., contained within the module or coupled to the outside of the module), or may be communicatively coupled to a BBU pack that includes the module (e.g., may be a part of circuitry of a BBU pack or of an electronic rack that is holding the BBU pack).

In one embodiment, the controller40is configured to control the valve (e.g., by transmitting a control signal to control circuitry of the valve, such as an electronic switch) in order to activate the heat-exchanging loop. Specifically, the controller may monitor certain criteria to determine whether cooling fluid should circulate throughout the system. For example, the controller may determine whether current is flowing from (or into) the battery cells (e.g., based on a current sense), which may indicate that the cells are in operation (e.g., discharging and/or charging). Upon making the determination, the controller causes the valve to open. More about how the controller causes cooling fluid to circulate throughout the system is described herein.

FIG. 3is a block diagram illustrating an example of a battery module with an exterior enclosure according to one embodiment. Specifically, this example illustrates a battery module31and the valve7are inside a (battery) exterior enclosure32. Not having the valve in the battery module may have several advantages. For example, by removing the valve, a size of the battery module31may be reduced as compared to the battery module1ofFIG. 1. As a result, less liquid coolant3may need to be used in order to cool the cells. As another example, since the valve7is a moving part (because it is configured to open/close), it may be prone to failure. As a result, by having it separate from the battery module31, a user may perform maintenance upon the valve and/or replace the valve when needed, while having the battery module31remain sealed. As yet another example, placing the battery module31inside a separate enclosure32may prevent any liquid (and/or vapor) that may leak out of the entire BBU pack from coming into contact with other electronics (e.g., servers on a server rack). In one embodiment, the battery exterior enclosure32may include connectors (e.g., quick-connect fittings) on 1) the outside of the enclosure that are coupled to respective supply and/or return lines that couple the enclosure to a cooling unit and/or 2) the inside of the enclosure that are coupled to respective supply and/or return lines that couple the enclosure to the battery module. In one embodiment, in addition to (or in lieu of) a valve7, pump21may be inside the battery exterior enclosure32.

As described herein, the present disclosure describes a self-activating battery thermal management system that activates a heat-exchanging loop (e.g., enables cooling fluid to flow through the loop). In one embodiment, the system20may activate during operation of the battery module (e.g., discharging and/or charging of the battery cells). To enable the flow of the cooling fluid, the system20may control at least one valve (e.g., valve7) and/or at least one pump (e.g., pump21) that is within the loop to cause cooling fluid to flow. As described herein, the system may control these components based on certain criteria. For example, the system may enable (and/or adjust) the flow (or flow rate) of the cooling fluid based on temperature and/or pressure within the battery module.FIG. 4is a block diagram illustrating an example of such a system. Specifically,FIG. 4shows the battery thermal management system that includes a battery module45and the controller40.

In this figure, the battery module includes a temperature sensor42and a pressure sensor41, each of which are electronically coupled (e.g., via a wired or wireless connection) to the controller40. Also shown, the controller40is electronically coupled to the valve7. The temperature sensor may be any type of sensor (e.g., a thermocouple, a resistance temperature detector (RTD), etc.) that is configured to detect (or sense) changes in temperature of the liquid coolant. Specifically, the sensor senses a temperature of the coolant and produces a corresponding electrical signal which represents (or indicates) a temperature (e.g., reading or value). In this example, the temperature sensor is located within the liquid coolant3. In another embodiment, however, the temperature sensor may be positioned anywhere inside the battery module, or may be positioned outside and on the module. The pressure sensor41may be any type of sensor (e.g., a piezoelectric pressure sensor, a force collector type, a pressure transducer, etc.) that is configured to detect (or sense) changes in (air) pressure within the battery module. Specifically, the pressure sensor senses air pressure (within the cell chamber12) in the battery module and produces a corresponding electrical signal that indicates the air pressure (e.g., reading or value) inside of the module. In this example, the pressure sensor is located above the liquid coolant3. In another embodiment, however, the pressure sensor may be located anywhere within the cell chamber of the module.

The controller40is configured to obtain (or receive) signals from sensor41and/or sensor42, and to control the valve7based on the obtained signals. Specifically, as the cells discharge/charge they generate heat that is absorbed by the liquid coolant, which in turn causes the temperature of the coolant to increase. The controller40monitors the temperature of the coolant (via the signal received from the sensor42) and determines whether to open/close the valve7based on the temperature. For example, the controller40may determine whether the temperature exceeds a threshold temperature, or is within a temperature range. If so, the controller40transmits a control signal43to the valve7, causing the valve to open in order to allow cooling fluid to flow through the heat-exchanging loop. Conversely, if the temperature is below the threshold temperature, the controller40transmits the control signal43to cause the valve to close. Similarly, the controller40may monitor the air pressure of the module in order to determine whether to open/close the valve7. Specifically, since the module is a closed (or sealed) environment, the heat generated by the cells will increase the temperature of the module, thereby causing the air pressure inside the module to increase (e.g., PV=nRT, where P is pressure and T is temperature). Thus, the controller40may determine whether the pressure exceeds a pressure threshold, or is within a temperature range. If so, the controller40causes the valve to change opening ratio. Thus, the valve is configured to allow cooling fluid to flow based on changes in temperature and/or pressure. In some embodiments, when the system20includes pump21, the controller40is configured to control the pump (e.g., adjust a speed at which the pump pushes fluid through the system) based on the temperature and/or pressure, as described herein. This control provides an optimal environment for the battery cells even though the BBU may dynamically change heat generation conditions (e.g., while discharging and while charging).

In one embodiment, the controller40is configured adjust the flow (or flow rate) of the cooling fluid (by adjusting a closed or open position of the valve) based on the temperature and/or pressure. For example, the controller40may cause the valve to open (e.g., half way) at a first temperature, and upon determining that the temperature has increased (e.g., to a higher second temperature) may cause the valve to open more (e.g., all the way).

FIG. 5is a block diagram an example of a battery thermal management system according to another embodiment. In this figure, the battery module55includes a liquid level sensor50, a filing port51, and a draining port52. Also shown, the controller40is electronically coupled to the sensor40and both ports. The level sensor50may be any type of sensor (e.g., a float switch, an ultrasonic level sensor, etc.) that is configured to detect changes in a level of liquid coolant within the battery module. Specifically, the sensor50senses a level of the liquid coolant and produces a corresponding electrical signal, which represents the level. The filling port51may be any port or valve that is configured to allow liquid to fill the battery module and the draining port52may be any port or valve that is configured to drawn liquid coolant from the module.

The controller40obtains the signal and determines whether the liquid coolant is too low or too high. For instance, the controller40may compare the level to a threshold level or a level threshold range. In response to the level of the liquid coolant being below the threshold (or a first threshold), the controller40transmits a control signal44to the filling port, causing the port to allow liquid coolant to flow through and into the module (e.g., by opening the port). Once the controller40determines that the level of coolant is at the threshold level, the controller40may transmit a control signal for the filling port to close. Similarly, in response to the level of the liquid coolant being above the threshold (or a second threshold that is higher than the first threshold), the controller40transmits a control signal44to the draining port, causing the port to drain liquid coolant from the module. In one embodiment, when the threshold is a range, the controller40may cause the filling port to fill the module when the level is below the range, and conversely the controller40may cause the draining port to drain the module when the level is above the range.

As described above, a BBU pack can be utilized as a backup power supply unit in an electronic rack of a data center. An electronic rack includes an array of server blades, each including a computer server for data processing. The electronic rack further includes a power supply to provide power to the server blades and a BBU pack to provide backup power to the server blades or other IT equipment when the power supply is unavailable.

FIG. 6is a block diagram illustrating an example of an electronic rack according to one embodiment. Electronic rack900may include one or more server slots to contain one or more servers respectively. Each server includes one or more information technology (IT) components (e.g., processors, memory, storage devices, network interfaces). According to one embodiment, electronic rack900includes, but is not limited to, CDU901, rack management unit (RMU)902(optional), a power supply unit (PSU)950, the BBU70(which may include a battery thermal management system with any of the components as described herein, such as a battery module (which may include a valve), a controller, and/or a cooling unit), and one or more server blades903A-903D (collectively referred to as server blades903). Server blades903can be inserted into an array of server slots respectively from frontend904or backend905of electronic rack900. The PSU950and/or BBU70may be inserted into any of server slots903within the electronic rack900. In one embodiment, one or more BBUs may be inserted into any of server slots903within the electronic rack900.

Note that although there are only four server blades903A-903D shown here, more or fewer server blades may be maintained within electronic rack900. Also note that the particular positions of CDU901, RMU902, PSU950, BBU70, and server blades903are shown for the purpose of illustration only; other arrangements or configurations of CDU901, RMU902, BBU70, and server blades903may also be implemented. Note that electronic rack900can be either open to the environment or partially contained by a rack container, as long as the cooling fans can generate airflows from the frontend to the backend.

In addition, a fan module can be associated with each of the server blades903, and the BBU70. In this embodiment, fan modules931A-931E, collectively referred to as fan modules931, and are associated with server blades903A-903D and BBS1respectively. Each of the fan modules931includes one or more cooling fans. Fan modules931may be mounted on the backends of server blades903and BBU70to generate airflows flowing from frontend904, traveling through the air space of the sever blades903, and existing at backend905of electronic rack900. In one embodiment, each of the fan modules may be mounted on the backends of the server blades903and one or more BBU70. BBU70may be any BBU described throughout this application.

In one embodiment, CDU901mainly includes heat exchanger911, liquid pump912, and a pump controller (not shown), and some other components such as a liquid reservoir, a power supply, monitoring sensors and so on. Heat exchanger911may be a liquid-to-liquid heat exchanger. Heat exchanger911includes a first loop with inlet and outlet ports having a first pair of liquid connectors coupled to external liquid supply/return lines931-932to form a primary loop. The connectors coupled to the external liquid supply/return lines931-932may be disposed or mounted on backend905of electronic rack900. The liquid supply/return lines931-932are coupled to a set of room manifolds, which are coupled to an external heat removal system, or external cooling loop. In addition, heat exchanger911further includes a second loop with two ports having a second pair of liquid connectors coupled to liquid manifold925to form a secondary loop, which may include a supply manifold to supply cooling liquid to server blades903and a return manifold to return warmer liquid back to CDU901. Note that CDUs901can be any kind of CDUs commercially available or customized ones. Thus, the details of CDUs901will not be described herein. As an example, the BBU70and/or the BBU80shown inFIG. 7may connect to925to complete a full fluid loop.

Each of server blades903may include one or more IT components (e.g., central processing units or CPUs, graphical processing units (GPUs), memory, and/or storage devices). Each IT component may perform data processing tasks, where the IT component may include software installed in a storage device, loaded into the memory, and executed by one or more processors to perform the data processing tasks. At least some of these IT components may be attached to the bottom of any of the cooling devices as described above. Server blades903may include a host server (referred to as a host node) coupled to one or more compute servers (also referred to as computing nodes, such as CPU server and GPU server). The host server (having one or more CPUs) typically interfaces with clients over a network (e.g., Internet) to receive a request for a particular service such as storage services (e.g., cloud-based storage services such as backup and/or restoration), executing an application to perform certain operations (e.g., image processing, deep data learning algorithms or modeling, etc., as a part of a software-as-a-service or SaaS platform). In response to the request, the host server distributes the tasks to one or more of the performance computing nodes or compute servers (having one or more GPUs) managed by the host server. The performance compute servers perform the actual tasks, which may generate heat during the operations.

Electronic rack900further includes optional RMU902configured to provide and manage power supplied to servers903, fan modules931, and CDU901. Optimization module921and RMC922can communicate with a controller in some of the applications. RMU902may be coupled to PSU950to manage the power consumption of the PSU. The PSU950may include the necessary circuitry (e.g., an alternating current (AC) to direct current (DC) or DC to DC power converter, backup battery, transformer, or regulator, etc.,) to provide power to the rest of the components of electronic rack900.

In one embodiment, RMU902includes optimization module921and rack management controller (RMC)922. RMC922may include a monitor to monitor operating status of various components within electronic rack900, such as, for example, computing nodes903, CDU901, and fan modules931. Specifically, the monitor receives operating data from various sensors representing the operating environments of electronic rack900. For example, the monitor may receive operating data representing temperatures of the processors, cooling liquid, and airflows, which may be captured and collected via various temperature sensors. The monitor may also receive data representing the fan power and pump power generated by the fan modules931and liquid pump912, which may be proportional to their respective speeds. These operating data are referred to as real-time operating data. Note that the monitor may be implemented as a separate module within RMU902.

Based on the operating data, optimization module921performs an optimization using a predetermined optimization function or optimization model to derive a set of optimal fan speeds for fan modules931and an optimal pump speed for liquid pump912, such that the total power consumption of liquid pump912and fan modules931reaches minimum, while the operating data associated with liquid pump912and cooling fans of fan modules931are within their respective designed specifications. Once the optimal pump speed and optimal fan speeds have been determined, RMC922configures liquid pump912and cooling fans of fan modules931based on the optimal pump speed and fan speeds.

As an example, based on the optimal pump speed, RMC922communicates with a pump controller of CDU901to control the speed of liquid pump912, which in turn controls a liquid flow rate of cooling liquid supplied to the liquid manifold925to be distributed to at least some of server blades903. Therefore, the operating condition and the corresponding cooling device performance are adjusted. Similarly, based on the optimal fan speeds, RMC922communicates with each of the fan modules931to control the speed of each cooling fan of the fan modules931, which in turn control the airflow rates of the fan modules931. Note that each of fan modules931may be individually controlled with its specific optimal fan speed, and different fan modules and/or different cooling fans within the same fan module may have different optimal fan speeds.

Note that some or all of the IT components of servers903(e.g.,903A,903B,903C, and/or903D) may be attached to any one of the cooling devices described above, either via air cooling using a heatsink or via liquid cooling using a cold plate. One server may utilize air cooling while another server may utilize liquid cooling. Alternatively, one IT component of a server may utilize air cooling while another IT component of the same server may utilize liquid cooling. In addition, a switch is not shown here, which can be either air cooled or liquid cooled. In one embodiment, the locations of the equipment or components of the electronic rack, such as the PSU and BBU may be varied, and may not be exactly as shown in this Figure.

FIG. 7is an example of a BBU with several battery modules according to one embodiment. This figure shows BBU80that includes five battery modules (e.g., battery module1) and a coolant distribution manifold71. In one embodiment, the distribution manifold71is coupled to heat exchanger911via manifold925to create a heat-exchanging loop for air-to-liquid heat exchange, as describe herein. Specifically, a supply line of each of the modules is coupled to a supply path72of the manifold71and a return line of each of the modules is coupled to a return path73of the manifold71in order for the modules to be a part of the heat exchanging loop. Each of the paths may be coupled to a corresponding path (or line) of the manifold925in order to allow coolant from the heat exchanger911to circulate through each of the battery modules. In one embodiment, the distribution manifold71may be coupled to one or more heat exchangers.

In some embodiments, rather than (or in addition to) having a coolant distribution manifold71, the battery modules of the BBU may (e.g., directly) connect to the liquid manifold925of the electronic rack.

The controller75is configured to activate at least some of the heat-exchanging loops within the battery modules (e.g., by controlling a valve integrated therein). Specifically, the controller may perform similar operations as described herein with respect to controller40. In one embodiment, however, each of the battery modules may include a controller that is configured to control the loop as described herein.

In another embodiment, one of the battery modules within the BBU80may include less components as illustrated herein. For example, a battery module may not include a cooling unit. Instead, a valve (or pump) within the battery module may allow coolant from the primary loop to circulate, as described herein.

As previously explained, an embodiment of the disclosure may be (or include) a non-transitory machine-readable medium (such as microelectronic memory) having stored thereon instructions, which program one or more data processing components (generically referred to here as a “processor”) to perform battery thermal management operations, such as controlling valves and/or pumps based on temperature/pressure of a battery pack (or BBU pack). In other embodiments, some of these operations might be performed by specific hardware components that contain hardwired logic. Those operations might alternatively be performed by any combination of programmed data processing components and fixed hardwired circuit components.

In some aspects, this disclosure may include the language, for example, “at least one of [element A] and [element B].” This language may refer to one or more of the elements. For example, “at least one of A and B” may refer to “A,” “B,” or “A and B.” Specifically, “at least one of A and B” may refer to “at least one of A and at least one of B,” or “at least of either A or B.” In some aspects, this disclosure may include the language, for example, “[element A], [element B], and/or [element C].” This language may refer to either of the elements or any combination thereof. For instance, “A, B, and/or C” may refer to “A,” “B,” “C,” “A and B,” “A and C,” “B and C,” or “A, B, and C.”