Performance improvement of an HVAC system that is thermally conditioned by a multi-branch cooling subsystem.

Abstract

A system for improving the performance of a heating, air conditioning, and ventilation (HVAC) system comprises rechargeable energy storage system (RESS) modules with high thermal mass, one or more auxiliary modules with low thermal mass, and a cooling system with a main refrigerant circuit and a refrigerant conditioning device. The HVAC system and individual parallel RESS refrigerant branches, connected in parallel to the auxiliary refrigerant branch(es), are connected to the main refrigerant circuit. An electronic controller determines the temperatures of the RESS module(s) and the auxiliary module(s) within their respective temperature ranges, conditions the refrigerant in the main circuit, and limits the refrigerant flow from it into the RESS refrigerant branch(es) when the temperature of the RESS module(s) is within a predefined temperature range.The control system also regulates the coolant flow from the main circuit to the auxiliary branch when the temperature of the auxiliary module is outside a second temperature range, in order to provide the target temperature coolant from the main coolant circuit to the HVAC system.

Description

The present description concerns prioritizing, improving and optimizing the performance of a heating, air conditioning and ventilation system (HVAC system) that is thermally conditioned by a multi-branch cooling system, such as that used for a rechargeable multi-cell energy storage system (RESS). A typical battery system for generating and storing electrical energy comprises one or more battery cells to supply power to a load. Multiple battery cells can be arranged in close proximity to one another to create a battery module, and multiple battery modules can be organized into a battery pack. Batteries can be broadly classified as primary or secondary. Primary batteries, also known as disposable batteries, are intended for use until depleted, at which point they are simply replaced with new ones. Secondary batteries, more commonly referred to as rechargeable batteries, utilize specific chemistries that allow them to be repeatedly recharged and reused, offering economic, environmental, and user-friendliness advantages over disposable batteries. Rechargeable batteries can be used to power a variety of items, including toys, consumer electronics, and motor vehicles. Certain rechargeable battery chemistries, such as lithium-ion cells, as well as external factors, can cause internal reaction rates that generate significant amounts of thermal energy. Prolonged exposure of a battery cell to elevated temperatures can cause it to experience thermal runaway, where the heat buildup in a single cell spreads to neighboring cells in the module, affecting the entire battery assembly. Additionally, temperature extremes can impair the battery cell's energy production. DE 10 2009 046 567 A1 describes a temperature control method and a battery system with which an optimal temperature range for operating a battery can be generated. The temperature control method for maintaining the temperature of a battery provides that the battery cells are arranged in several separate modules integrated in a temperature control circuit. During a heating phase, heating occurs in stages: in a first step, only a first module is heated by means of a temperature control medium operating in the temperature control circuit and heated by a heating element; and in at least one further step, heat generated during the operation of at least the first module is used to heat at least one further module. WO 2020 / 003693A1 describes a battery temperature control device. This device regulates the temperature of secondary batteries comprising multiple rechargeable battery packs connected in parallel. It includes heat transfer fluid supply units and a control device. The heat transfer fluid supply units independently supply each of the battery packs with the heat transfer fluid. The control device performs temperature control to direct the heat transfer fluid supply units to increase the heat transfer fluid supply rate to the battery pack whose temperature is to be regulated more than to the other battery packs, prioritizing this based on the battery state of the multiple battery packs.In this way, it is possible to prioritize increasing the amount of heat exchange between the heat transfer medium and a specific battery pack over other battery packs. Therefore, it is possible to adjust the temperature of a particular battery pack before the others. Accordingly, thermal energy must be managed effectively to optimize the performance of the battery system. Generally, devices such as heat sinks or cooling plates with circulating coolant are used to remove heat from battery systems. Accordingly, the object of the present invention is to provide a system that enables more effective management of thermal energy. The problem is solved by the subject matter of the independent claim. A system according to the invention for improving the performance of a heating, air conditioning, and ventilation system (HVAC system) comprises a rechargeable multi-cell energy storage system (RESS) with a plurality of RESS modules having a relatively high thermal mass. The system also includes an auxiliary module with a relatively low thermal mass and a cooling subsystem comprising a main coolant circuit fluidically connected to the HVAC system and configured to circulate coolant. The cooling subsystem further comprises at least one coolant heat conditioning device arranged in the main coolant circuit. The cooling subsystem also includes a plurality of parallel RESS coolant branches, each RESS coolant branch being configured to receive coolant from the main coolant circuit to adjust the temperature of one of the respective RESS modules.The cooling subsystem additionally includes an auxiliary coolant branch, which is arranged in parallel to the multitude of RESS coolant branches and is configured to receive coolant from the main coolant circuit in order to adjust the temperature of the auxiliary module. The system also includes an electronic controller in operational communication with the cooling subsystem and is configured to determine when the temperature of at least one of the RESS modules is within a first predetermined temperature range. The electronic controller is additionally configured to determine when the temperature of the auxiliary module is outside a second predetermined temperature range. The electronic controller is further configured to thermally condition the coolant in the main coolant circuit to a target temperature. The electronic controller is further configured to limit a coolant flow from the main coolant circuit individually into at least one of the RESS coolant branches when the temperature of the corresponding at least one RESS module is within the first predetermined temperature range.The electronic control is additionally configured to regulate coolant flow from the main coolant circuit to the auxiliary coolant branch when the auxiliary module temperature is outside the second predetermined temperature range. Regulating the coolant flow to the auxiliary coolant branch under such conditions is intended to maintain the target coolant temperature in the main coolant circuit and supply such coolant to the HVAC system, thereby improving the HVAC system's performance. The coolant flow can be regulated in the auxiliary coolant branch to additionally provide at least a predefined minimum flow rate of the coolant through the cooling unit system for the required performance of the HVAC system. RESS modules with relatively high thermal mass can comprise individual battery modules with a large number of battery cells. The cooling subsystem may additionally include at least one RESS flow valve in operational communication with the electronic control and configured to regulate and distribute the coolant received from the main coolant circuit through the multitude of RESS coolant branches. The RESS flow valve(s) can be configured as a multi-way valve arrangement located at a junction between the main coolant circuit and the multitude of RESS coolant branches, and is configured to control the flow of coolant into each of the RESS coolant branches. The RESS flow valve(s) can be configured as a plurality of individual throttle valves, with each throttle valve being located in one of the plurality of RESS coolant branches upstream of the corresponding RESS module and configured to control the flow of coolant into the RESS coolant branch concerned. Each RESS coolant branch can include a one-way valve configured to control the flow of coolant from the affected RESS coolant branch. The cooling subsystem may also include a bypass flow valve in operational communication with the electronic control and configured to regulate the coolant in the auxiliary coolant branch. The cooling subsystem may additionally include a one-way valve configured to control the flow of coolant from the auxiliary coolant branch. The cooling subsystem may further include a fluid pump configured to circulate the coolant through the main coolant circuit. The at least one coolant heat conditioning device may include a coolant heater configured to add heat energy to the coolant in the main coolant circuit and / or a coolant-to-air heat exchanger configured to remove heat energy from the coolant in the main coolant circuit. A motor vehicle that uses the system described above, and a method for improving the performance of the HVAC system are also disclosed. The above features and advantages, as well as other features and advantages of the present description, will be readily apparent from the following detailed description of the embodiment(s) and the best way(s) for carrying out the described description in conjunction with the accompanying drawings and the accompanying claims. Fig. 1 is a schematic top view of an embodiment of a motor vehicle incorporating multiple power sources, a heating, air conditioning, and ventilation system (HVAC system), a multi-cell rechargeable energy storage system (RESS) with individual modules configured for generating and storing electrical energy used by vehicle systems, an auxiliary module, and a system for improving the performance of the HVAC system as described. Fig. 2 is a schematic representation of the system for improving the performance of the HVAC system shown in Fig.Figure 1 shows an embodiment of a cooling system with a main coolant circuit and several parallel coolant branches for temperature control in individual battery modules and in the auxiliary module, as described. Figure 3 is a schematic representation of the system for improving the performance of the HVAC system shown in Figure 1, including another embodiment of the cooling system with a main coolant circuit and several parallel coolant branches for temperature control in individual battery modules and in the auxiliary module, as described. Figure 4 illustrates a method for improving the performance of the HVAC system using the cooling system shown in Figures 1-3, as described. With reference to the drawings, in which the same reference numerals refer to the same components, Fig. 1 shows a schematic view of a motor vehicle 10 with a driver / passenger compartment 10A and a powertrain 12. The vehicle 10 may be, but is not limited to, a commercial vehicle, an industrial vehicle, a passenger car, an aircraft, a watercraft, a train, or the like. It is also considered that the vehicle 10 may be a mobile platform, such as an aircraft, an all-terrain vehicle (ATV), a boat, a personal mobility device, a robot, and the like, to achieve the purposes of this description. The powertrain 12 comprises a power source 14 configured to generate a power source torque T (shown in Fig. 1) for driving the vehicle 10 via driven wheels 16 relative to a road surface 18.Power source 14 is represented as an electric motor generator. As shown in Fig. 1, the powertrain 12 can include an additional power source 20, such as an internal combustion engine. The power sources 14 and 20 can work together to supply energy to the vehicle 10. The vehicle 10 also includes a central processing unit (CPU) 22 and a multi-cell rechargeable energy storage system, RESS, 24, configured to generate and store electrical energy through heat-generating electrochemical reactions to supply electrical energy to the power sources 14 and 20. The vehicle 10 also includes a high-voltage data bus, or BUS 25, for communicating electrical signals between different vehicle systems. The vehicle 10 further includes a vehicle heating, air conditioning, and ventilation system, HVAC system, 26, configured to control the temperature in the vehicle compartment 10A.The CPU 22 controls various systems of the vehicle 10, including the powertrain 12, to generate a predetermined amount of power source torque T and the HVAC 26. The RESS 24 can be connected via the BUS 25 to the power sources 14 and 20, to the electronic CPU 22, and to other vehicle systems, such as the HVAC 26. As shown in Figures 1-3, the RESS 24 comprises a plurality of battery cells 28, such as rechargeable lithium-ion cells, arranged in individual battery modules, such as a first module 30-1, a second module 30-2, and a third module 30-3. The modules 30-1, 30-2, and 30-3 can be electrically connected in series or parallel. Within individual modules, for example, 30-1, 30-2, and 30-3, different battery cells 28 can be electrically connected in series or parallel and assembled into cell groups. Such cell groups are then electrically connected in series and assembled into individual modules. Although three individual battery modules are specifically shown, the RESS 24 is intended to comprise at least two modules of each type, and several modules can be organized into battery packs. The remainder of this description focuses on the construction of the RESS 24 with three battery modules 30-1, 30-2, 30-3, each battery module comprising a desired number of battery cells 28. As shown in Fig. 2 and Fig. 3, each battery module 30-1, 30-2, 30-3 includes a respective battery module housing 32-1, 32-2, 32-3, which is connected to the chassis mass and configured to accommodate and support the corresponding battery cells 28. The RESS 24 may also include a battery pack housing 33, which is surrounded by an environment 34 and configured to accommodate and support the battery modules 30-1, 30-2, 30-3 (shown in Fig. 1). As shown in Fig. 2 and Fig. 3, the RESS 24 also includes a cooling subsystem 36 configured to remove heat energy from various temperature-sensitive components of the RESS. The cooling subsystem 36 includes a main coolant circuit 38 configured to circulate a coolant 40 through the RESS 24 and the HVAC system 26. As shown, the cooling subsystem 36 also includes a fluid pump 42 configured to circulate the coolant 40 through the main coolant circuit 38. The cooling subsystem 36 further comprises a plurality of coolant branches, shown as a first branch 44-1, a second branch 44-2 and a third branch 44-3, in fluid communication with the main coolant circuit 38. Each of the coolant branches 44-1, 44-2, 44-3 extends through a respective battery module 30-1, 30-2, 30-3 in the vicinity of and along the constituent battery cells 28. Furthermore, each coolant branch 44-1, 44-2, 44-3 is configured to receive a portion of the coolant 40 from the main coolant circuit 38. The coolant branches 44-1, 44-2, 44-3 are arranged fluidically in parallel to receive their respective portions of the coolant 40. The coolant branches 44-1, 44-2, 44-3 are thus configured to circulate their respective portions of the coolant 40 independently and to adjust the temperature of the corresponding battery modules 30-1, 30-2, 30-3 (by removing or adding heat energy). Accordingly, each coolant branch 44-1, 44-2, 44-3 passes through one of the battery module housings 32-1, 32-2, 32-3. As shown, the main coolant circuit 38 is in fluid communication with one or more auxiliary coolant branches, such as branch 44-4 shown in Fig. 2 and Fig. 3, which is arranged parallel to the coolant branches 44-1, 44-2, 44-3. For example, each additional coolant branch 44-4 (hereinafter referred to as the auxiliary coolant branch) can be configured to receive coolant 40 from the main coolant circuit 38 and circulate the coolant through an auxiliary module or device, generally identified by reference numeral 45. Such an auxiliary module or device may be, for example, an auxiliary power module (APM), a battery disconnect unit (BDU) comprising various electrical switches and relays, a DC / DC converter for supplying 12 V / 48 V power to the vehicle 10, an optionally isolated coolant bypass, and so forth, each having specific temperature requirements and / or heat energy absorption / dissipation characteristics. Additionally, the main coolant circuit 38 is fluidically connected to the HVAC system 26 to provide thermal conditioning of the HVAC system.For example, the cooling subsystem 36 can thermally condition the HVAC system 26 via a dedicated bidirectional heat pump operating through two HVAC heat exchangers, one heat exchanger coupling to the passenger compartment 10A air (not shown) and the other heat exchanger, designated by reference numeral 56-1, coupling to the main coolant circuit 38. Accordingly, at least some of the coolant branches 44-1, 44-2, 44-3 are configured to receive respective portions of the coolant 40 from the main coolant circuit 38 in order to regulate the temperature of the corresponding individual battery modules 30-1, 30-2, 30-3. Likewise, the respective branch(es) 44-4 is / are configured to receive a portion of the coolant 40 from the main coolant circuit 38 in order to regulate the temperature of the corresponding auxiliary module(s) 45. Each of the battery modules 30-1, 30-2, 30-3 and individual auxiliary modules 45 can generate, transfer, and / or dissipate thermal energy. In addition, each of the battery modules 30-1, 30-2, 30-3 and auxiliary module / auxiliary modules 45 is characterized by an individual mass that is central for the absorption and dissipation of thermal energy, which is defined herein as ‘thermal mass’.It is understood that a higher thermal mass is capable of absorbing or dissipating a greater amount of thermal energy from its surroundings by conduction, convection, or radiation than a lower thermal mass. In the context of the present description, each of the battery modules 30-1, 30-2, 30-3 is defined by a relatively or comparatively high thermal mass, while each individual auxiliary module 45 is defined by a comparatively lower thermal mass. With further reference to Figures 2 and 3, the RESS 24 can also include an inlet manifold 46 configured to connect the main coolant circuit 38 to the coolant branches 44-1, 44-2, 44-3, and an outlet manifold 48 configured to connect the coolant branches back to the main coolant circuit. Accordingly, the inlet and outlet manifolds 46 and 48 are configured together to maintain the circulation of coolant 40 through the cooling subsystem 36. The cooling subsystem 36 additionally includes at least one RESS flow valve 50. The RESS flow valve(s) 50 is / are configured to regulate the coolant 40 circulating through and being received by the main coolant circuit 38 and to distribute it through the individual coolant branches 44-1, 44-2, 44-3.In other words, the RESS flow valve(s) 50 is / are specifically structured and operated to provide independent control of the coolant flow into each individual coolant branch 44-1, 44-2, 44-3. As shown in Fig. 2, the RESS flow valve 50 can be a multi-way valve arrangement located at a junction, such as the inlet manifold 46, between the main coolant circuit 38 and the plurality of coolant branches 44-1, 44-2, 44-3 upstream of each battery module 30-1, 30-2, 30-3. The embodiment of the multi-way valve arrangement of the RESS flow valve 50 can be configured to control the flow of coolant 40 into each of the coolant branches 44-1, 44-2, 44-3. As shown in Fig. 3, the RESS flow valve(s) 50 can be a plurality of individual throttle valves 50-1, 50-2, 50-3. Each affected throttle valve 50-1, 50-2, 50-3 can be located in one of the multiple coolant branches 44-1, 44-2, 44-3 upstream of the corresponding battery module 30-1, 30-2, 30-3 and can be configured to control the flow of coolant 40 into the affected coolant branch. As shown in Figures 2 and 3, each coolant branch 44-1, 44-2, 44-3 can include a respective one-way valve 52-1, 52-2, 52-3. The one-way valves 52-1, 52-2, 52-3 are configured to prevent backflow of the coolant 40 into the corresponding coolant branches 44-1, 44-2, 44-3. Each of the one-way valves 52-1, 52-2, 52-3 is located downstream of the RESS flow valve(s) 50 and downstream of the corresponding battery module 30-1, 30-2, 30-3. Accordingly, each one-way valve 52-1, 52-2, 52-3 is configured to control the flow of the corresponding portion of the coolant 40 through and out of the affected coolant branch 44-1, 44-2, 44-3. The cooling subsystem 36 may also include a bypass flow valve 54 configured to control the coolant flow in the auxiliary coolant branch 44-4 received from the main coolant circuit 38. Additionally, the cooling subsystem 36 may include a one-way valve 52-4 configured to control the flow of coolant 40 from the auxiliary coolant branch 44-4. The cooling subsystem 36 may also include one or more coolant heat conditioning devices arranged in the main coolant circuit 38. In particular, as shown in Figures 2 and 3, the coolant heat conditioning devices may include a coolant-to-air heat exchanger 56-2 configured to remove heat energy from the coolant 40 in the main coolant circuit 38 downstream of the RESS and the auxiliary modules, and / or a coolant heater 56-3 configured to add heat energy to the main circuit coolant.For example, one embodiment of the coolant-air heat exchanger 56-2 can dissipate heat to the environment 34, while the coolant heater 56-3 can use electrical resistance to thermally condition the coolant 40 accordingly. The coolant-air heat exchanger 56-2 can be placed directly in series with the main coolant circuit 38 or, although not shown, can be thermally connected to the main coolant circuit by a coolant-coolant heat exchanger or a valve body arrangement for mixing coolants through a separate coolant circuit. As shown in Figures 1-3, the multi-cell RESS 24 can additionally include an electronic controller 58, which can either be electronically connected to or part of the CPU 22. The electronic controller 58 is in operational communication with the cooling subsystem 36; that is, it is configured or programmed to control the operation of the cooling subsystem and can be structured to manage the operation of the RESS 24 as well as the auxiliary module 45. As shown, the electronic controller 58 is in operational communication with the fluid pump 42, the RESS flow valve(s) 50, the bypass flow valve 54, the HVAC heat exchanger 56-1, and the coolant heater 56-3. To support the necessary management of the RESS 24 and / or the cooling subsystem 36, the electronic controller 58 includes, in particular, a processor and tangible, non-volatile memory containing the necessary programmed instructions.The controller's memory can be a suitable writable medium involved in providing computer-readable data or process instructions. Such a writable medium can take many forms, including, but not limited to, non-volatile and volatile media. Non-volatile media for the electronic control 58 can include, for example, optical or magnetic disks and other persistent storage media. Volatile media can include, for example, dynamic random-access memory (DRAM), which can represent main memory. The instructions programmed into the control 58 can be transmitted through one or more transmission media, including coaxial cable, copper wire, and fiber optic cable, including the wires comprising a system bus coupled to a computer processor or via a wireless connection. Memory for the electronic control 58 can also include flexible disks, hard disks, magnetic tape, other magnetic media, CD-ROMs, DVDs, other optical media, and so on.The electronic control 58 may be configured or equipped with other required computer hardware, such as a high-speed clock, required analog-to-digital (A / D) and / or digital-to-analog (D / A) circuits, input / output (I / O) circuits and devices, and suitable signal conditioning and / or buffer circuits. The electronic control 58 can be configured to regulate the flow of coolant 40 into the individual battery modules 30-1, 30-2, 30-3 through the corresponding coolant branches 44-1, 44-2, 44-3 via the fluid pump 42 and the RESS flow valve(s) 50. Similarly, the electronic control 58 can be configured to regulate the flow of coolant 40 from the main coolant circuit 38 into the auxiliary module 45 via the auxiliary coolant branch 44-4. Algorithm(s), generally specified by reference numeral 60, required by or accessible to the electronic control 58, can be stored in the control's memory and executed automatically to facilitate the operation of the RESS 24 and / or the cooling subsystem 36. The function of the cooling subsystem 36 can be controlled by the electronic control 58 under normal operating conditions, as well as for the purpose of improving (or optimizing) the performance of the individual RESS modules 30-1, 30-2, 30-3, and the auxiliary module 45 by prioritizing their thermal conditioning. In general, during the regular operation of the RESS 24, the coolant flow through the coolant branches 44-1, 44-2, 44-3 is used to absorb thermal energy released by the battery cells 28 in the individual battery modules 30-1, 30-2, 30-3 and to stabilize the RESS operation. During various extreme and / or transient conditions, the RESS modules 30-1, 30-2, 30-3 and auxiliary systems and modules 45 can benefit from thermal conditioning by controlling the temperature of the coolant 40. However, under certain conditions, the physical and thermal properties of the RESS modules 30-1, 30-2, 30-3 can affect the operating requirements of the HVAC system 26. For example, during cold starts and vehicle warm-up, the RESS modules 30-1, 30-2, and 30-3 can benefit from additional thermal energy to generate the required power output for vehicle propulsion. Simultaneously, the HVAC system 26 can be requested to provide heat to the passenger compartment 10A. To meet these requirements, the coolant heater 56-3 can be instructed to add thermal energy to the coolant 40. However, optimal temperature ranges for the two systems under these conditions are likely to differ. Since both the RESS 24 and the HVAC system 26 receive thermal conditioning from the same body of coolant 40, RESS modules with a higher thermal mass than the auxiliary module(s) 45 will continue to absorb thermal energy from the coolant 40 beyond the point where one or more RESS modules are within an acceptable temperature range. Accordingly, the RESS module(s) absorb energy that would be of greater use to the HVAC system 26, thus delaying the cabin's warm-up. Similarly, if the vehicle 10 is operating in a hot environment, the coolant-to-air heat exchanger 56-2 can be instructed to remove heat energy from the coolant 40. The RESS modules will continue to transfer heat energy to the coolant 40 even if one or more modules are within their acceptable temperature range. Since each RESS module has a higher thermal mass than at least one of the auxiliary modules 45, if the RESS 24 and the HVAC system 26 continue to draw coolant from the main circuit 38, the HVAC system will be able to transfer less heat to the coolant 40 due to the competing heat output from the RESS modules, thus delaying the cabin's cooling. As shown in Fig. 1, the vehicle 10 also includes a system 62 for prioritizing, improving, and optimizing the performance of the associated RESS and auxiliary modules by prioritizing their thermal conditioning. The electronic control unit 58 is programmed with specific algorithm(s) 60 to operate the system. In particular, the algorithm(s) 60 include a status mode configured to monitor the temperatures of the RESS modules 30-1, 30-2, 30-3 and the auxiliary module(s) 45, for example, via the respective RESS temperature sensor(s) 64-1, 64-2, 64-3 and auxiliary temperature sensor 64-4. The electronic control unit 58 is programmed to determine when the temperature of at least one of the RESS modules 30-1, 30-2, 30-3 is within a first predetermined temperature range 66-1. The first predetermined temperature range 66-1 for batteries can be from -20 to +50 degrees Celsius. The electronic control 58 is also programmed to determine when the temperature of a specific auxiliary module 45, such as the BDU, APM, OBCM, or coolant bypass, falls outside a second predetermined temperature range 66-2. The second predetermined temperature range 66-2 for BDU, APM, and OBCM auxiliary modules can range from -35 to +70 degrees Celsius. For cold ambient operation (for example, ambient 34 of -10 degrees Celsius), the coolant 40 can be routed through the coolant heater 56-3 to raise the coolant temperature above ~5 degrees Celsius for the heating mode of the HVAC system 26. For hot operation (for example, ambient 34 of 35 degrees Celsius), the coolant 40 can be routed through the coolant-to-air heat exchanger 56-2 to lower the coolant temperature below ~40 degrees Celsius for the cooling mode of the HVAC system 26.The electronic control 58 is also programmed to heat condition the coolant 40 (increase or decrease its temperature) in the main coolant circuit 38 to a target temperature 68 using the appropriate coolant heat conditioning device 56-2 or 56-3. The electronic control 58 is additionally programmed to limit, i.e., throttle or shut off, a coolant flow 40 (via suitable RESS flow valve(s) 50) from the main coolant circuit 38 individually into at least one of the RESS coolant branches 44-1, 44-2, 44-3, when the temperature of the corresponding RESS module(s) is within the first predetermined temperature range 66-1. Such a limitation of the coolant flow 40 by the respective RESS module(s) 30-1, 30-2, 30-3 would maintain a larger volumetric flow rate of coolant through the auxiliary module(s) 45 and limit the influence of the affected RESS module(s) on the coolant temperature in the cooling subsystem 36.The electronic control 58 is further programmed to regulate a coolant flow 40 from the main coolant circuit 38 into the auxiliary coolant branch 44-4 when the temperature of the auxiliary module 45, for example the HVAC, is outside the second predetermined temperature range 66-2. By limiting the flow through the RESS module(s) 30-1, 30-2, 30-3, more coolant 40 would be routed through the auxiliary module(s) 45. The coolant flow 40 can be regulated to at least a predefined minimum flow rate for the required output of the HVAC 26 by allowing a higher flow rate through the auxiliary coolant branch 44-4. Additionally, the coolant flow rate through the auxiliary module(s) 45 can be further increased if the auxiliary module(s) is / are outside the second predetermined temperature range 66-2. After the coolant 40 has flowed through the auxiliary coolant branch 44-4, the electronic control 58 can regulate the coolant to flow through the HVAC heat exchanger 56-1 to provide the coolant at target temperature from the main coolant circuit to the HVAC to thermally condition the HVAC system 26 to either heat or cool the cabin 10A.The net result of such prioritized thermal conditioning is an improved performance of the HVAC system 26, such as increased HVAC heat output during the cold start of the vehicle 10 or reduced heat transfer for cooler cabin air during hot ambient conditions. A method 100 for prioritizing, improving, and optimizing the performance of the HVAC system 26, which is thermally conditioned by the cooling subsystem 36, is shown in Fig. 4 and is described below with reference to the structure shown in Figs. 1-3. The method 100 begins in frame 102 by monitoring the temperatures of the RESS modules 30-1, 30-2, 30-3 and the auxiliary module(s) 45 via the electronic control 58, such as via the respective RESS temperature sensor(s) 64-1, 64-2, 64-3 and auxiliary temperature sensor 64-4, and can also monitor the temperature in the passenger compartment 10A and the environment 34. In frame 102, the method can additionally include capturing an operator request to start the vehicle 10 via the electronic control unit 58, for example, a key-on mode of the powertrain 12, so that the RESS 24 begins to discharge energy. Following frame 102, the method transitions to frame 104. In frame 104, the method comprises determining, via the electronic control 58, when the temperature of the RESS module(s) 30-1, 30-2, 30-3 is within the first predetermined temperature range 66-1. After frame 104, the method proceeds to frame 106. In frame 106, the method comprises determining, via the electronic control 58, when the temperature of a specific auxiliary module 45 is outside a second predetermined temperature range 66-2. After completion of frame 106, the method proceeds to frame 108. In frame 108, the method comprises thermally conditioning, via the electronic control 58 (using either the coolant-to-air heat exchanger 56-2 or the coolant heater 56-3), the coolant in the main coolant circuit 38 to a target temperature 68.Such thermal conditioning can, for example, include raising the temperature of the coolant 40 above the predetermined value 68 to heat the passenger compartment 10A via the HVAC system 26 after a cold start of the vehicle. The procedure then proceeds to frame 110 after frame 108. In frame 110, the method comprises limiting, via electronic control 58, the coolant flow 40 (via RESS flow valve(s) 50) from the main coolant circuit 38 individually into at least one of the RESS coolant branches 30-1, 30-2, 30-3 when the temperature of the corresponding RESS module(s) is within the first predetermined temperature range 66-1. Such limitation of the coolant flow 40 into the RESS coolant branch(es) 30-1, 30-2, 30-3 is intended to maintain a larger volumetric flow rate of coolant through the auxiliary module(s) 45 and to limit the influence of the affected RESS module(s) on the coolant temperature in the cooling subsystem 36. Following frame 110, the method transitions to frame 112.In framework 112, the procedure includes the control of the electronic control 58 of the coolant flow 40 from the main coolant circuit 38 into the designated auxiliary coolant branch 44-4 when the temperature of the corresponding auxiliary module 45 is outside the second predetermined temperature range 66-2. Additionally, in frame 112, the coolant flow 40 through the HVAC heat exchanger 56-1 can be regulated to provide at least a predefined minimum volume flow rate for the required output of the HVAC 26 by allowing a higher volume flow through the auxiliary coolant branch(es) 44-4. For cold system operation 62, after the coolant 40 has passed through the auxiliary coolant branch 44-4, the electronic control 58 can regulate the coolant flow through the coolant heater 56-3 and regulate the coolant temperature to be above ~5 degrees Celsius for the heating mode of the HVAC system 26. For hot system operation 62, the electronic control 58 can, after the coolant 40 has been routed through the auxiliary coolant branch 44-4, regulate the coolant so that it flows through the coolant-air heat exchanger 56-2, and regulate the coolant temperature so that it is below ~40 degrees Celsius for the cooling mode of the HVAC system 26.The intended result of regulating the coolant flow 40 into the affected auxiliary coolant branch 44-4 is to improve the performance of the HVAC system 26. Following frame 112, the procedure for continued monitoring of the respective RESS and auxiliary module temperatures can return to frame 102. If the various monitored temperatures have been balanced or determined to have reached predefined steady-state conditions or acceptable limit conditions, the procedure can end in frame 114. Alternatively, if the powertrain 12 and other vehicle systems, such as the auxiliary module(s) 45, have been switched off and the fluid pump 42 has been deactivated, the procedure can shut down the current flow and power generation in the RESS 24 and similarly end in frame 114. Overall, the procedure 100 utilizes the flexibility provided by individually controlled parallel coolant branches of the cooling subsystem 36 to enhance the performance of the HVAC system 26 using a common coolant supply with the RESS 24 and the auxiliary module(s) 45.

Claims

System for improving the performance of a heating, air conditioning, and ventilation system (26), comprising: a multi-cell rechargeable energy storage system (RESS) (24) with a plurality of RESS modules (30-1, 30-2, 30-3) having a relatively high thermal mass; an auxiliary module (45) having a relatively low thermal mass; a cooling subsystem (36), comprising: a main coolant circuit (38) fluidically connected to the HVAC system (26) and configured to circulate coolant (40); at least one coolant heat conditioning device (56-1, 56-2, 56-3) arranged in the main coolant circuit (38); a plurality of parallel RESS coolant branches (44-1, 44-2, 44-3), each RESS coolant branch being configured to circulate coolant (40) to take in from the main coolant circuit (38) to set the temperature of one of the respective RESS modules (30-1, 30-2, 30-3);and an auxiliary coolant branch (44-4) arranged in parallel to the plurality of RESS coolant branches (44-1, 44-2, 44-3) and configured to receive coolant from the main coolant circuit to adjust the temperature of the auxiliary module (45); and an electronic control (58) in operational communication with the cooling subsystem (36) and configured to: determine when the temperature of at least one of the RESS modules (44-1, 44-2, 44-3) is within a first predetermined temperature range (44-1); determine when the temperature of the auxiliary module (45) is outside a second predetermined temperature range (44-2); and heat condition the coolant (40) in the main coolant circuit (38) to a target temperature (48).Limiting a coolant flow from the main coolant circuit (38) individually into at least one of the RESS coolant branches (44-1, 44-2, 44-3) when the temperature of the corresponding at least one RESS module (30-1, 30-2, 30-3) is within the first predetermined temperature range (66-1); and controlling a coolant flow (40) from the main coolant circuit (38) into the auxiliary coolant branch (44-4) when the temperature of the auxiliary module (45) is outside the second predetermined temperature range (66-2) in order to supply the coolant (40) at the target temperature (68) from the main coolant circuit (38) to the HVAC system (26). System according to claim 1, wherein the RESS modules (30-1, 30-2, 30-3) with relatively high thermal mass comprise individual battery modules with a plurality of battery cells (28). System according to claim 1, wherein the cooling subsystem (36) additionally comprises at least one RESS flow valve (50) in operational communication with the electronic control (58) and is configured to control the coolant (40) received from the main coolant circuit (38) and to distribute it via the plurality of RESS coolant branches (44-1, 44-2, 44-3). System according to claim 3, wherein the at least one RESS flow valve (50) is a multi-way valve arrangement located in a connection point (46) between the main coolant circuit (38) and the plurality of RESS coolant branches (44-1, 44-2, 44-3) and configured to control a flow of the coolant (40) into each of the RESS coolant branches (44-1, 44-2, 44-3). System according to claim 3, wherein the at least one RESS flow valve (50) is a plurality of individual throttle valves (50-1, 50-2, 50-3), each throttle valve (50-1, 50-2, 50-3) being arranged in one of the plurality of RESS coolant branches (44-1, 44-2, 44-3) upstream of the corresponding RESS module (30-1, 30-2, 30-3) and being configured to control a flow of the coolant (40) into the affected RESS coolant branch (44-1, 44-2, 44-3). System according to claim 1, wherein each RESS coolant branch (44-1, 44-2, 44-3) comprises a one-way valve (52-1, 52-2, 52-3) configured to control a flow of coolant (40) from the affected RESS coolant branch (44-1, 44-2, 44-3). System according to claim 1, wherein the cooling subsystem (36) further comprises a bypass flow valve (54) in operational communication with the electronic control (58) and is configured to control the coolant (40) in the auxiliary coolant branch (44-4), and a one-way valve (52-4) configured to control a flow of the coolant (40) out of the auxiliary coolant branch (44-4). System according to claim 1, wherein the cooling subsystem (36) further comprises a one-way valve (52-4) configured to control a flow of the coolant (40) from the auxiliary coolant branch (44-4). System according to claim 1, wherein the cooling subsystem (36) further comprises a fluid pump (42) configured to circulate the coolant (40) through the main coolant circuit (38). System according to claim 1, wherein the at least one coolant heat conditioning device (56-1, 56-2, 56-3) comprises a coolant heater (56-3) configured to add heat energy to the coolant (40) in the main coolant circuit (38), and / or a coolant-to-air heat exchanger (56-2) configured to remove heat energy from the coolant (40) in the main coolant circuit (38).

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