Energy storage system cold start power discharge improvement using a multi-branch coolant system

Abstract

A system for improving the cold-crank discharge performance of a multi-cell rechargeable energy storage system (RESS) with battery cells connected in electrically parallel battery modules includes a cooling subsystem. The subsystem comprises a main coolant circuit that circulates coolant, several coolant branches arranged in parallel, and one or more flow valves that regulate and distribute coolant from the main circuit through the branches. At least some coolant branches draw portions of the coolant from the main circuit to adjust the temperature of corresponding individual battery modules. An electronic controller detects, via a heater, when the RESS temperature is at or below a predetermined value and increases the temperature of the coolant in the main coolant circuit above the predetermined value.The controller also selects one or more battery modules and identifies one or more associated coolant branches. Furthermore, the controller shuts off coolant flow to coolant branches of one or more unselected battery modules to exclusively heat one or more selected battery modules and improve RESS cold-crank discharge performance.

Description

INTRODUCTION

[0001] The present disclosure relates to the improvement of cold start power discharge in a multi-cell rechargeable energy storage system (RESS) using a multi-branch coolant system.

[0002] A typical battery system for generating and storing electrical energy includes one or more battery cells to supply power to a load. Multiple battery cells can be placed in close proximity to each other 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 to be used until depleted, at which point they are simply replaced with new ones. Secondary batteries, more commonly called rechargeable batteries, utilize specific chemistries that allow them to be repeatedly recharged and reused, offering economic, environmental, and user-friendliness advantages over disposable batteries.

[0003] Rechargeable batteries can be used to power a variety of devices, 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 heat energy. Exposing a battery cell to elevated temperatures for extended periods can cause it to experience thermal runaway, where heat buildup in a single cell spreads to neighboring cells in the module, affecting the entire battery assembly. Additionally, temperature extremes can impair battery cell power output. Therefore, thermal energy must be managed effectively to optimize battery system performance.In general, devices such as heat sinks or cooling plates with circulating coolant are used to remove heat from battery systems. DESCRIPTION

[0004] A system for improving the cold-crank discharge performance of a multi-cell rechargeable energy storage system (RESS) with a plurality of battery cells arranged in individual battery modules connected electrically in parallel includes a cooling system. The cooling system comprises a main coolant circuit circulating coolant, a coolant heater located within the main coolant circuit, and a plurality of coolant branches arranged in parallel. At least some of the coolant branches are configured to receive portions of coolant from the main coolant circuit to adjust the temperature of corresponding individual battery modules. The cooling system also includes one or more flow valves for regulating and distributing the coolant from the main coolant circuit through the coolant branches.The system also includes an electronic control unit that is in operational communication with the cooling system.

[0005] The electronic control is configured to detect that the RESS temperature is at or below a predetermined value. The electronic control is also configured to raise the coolant temperature above the predetermined value using the coolant heater in the main coolant circuit and to select at least one, but fewer than all, battery modules in the RESS using predetermined criteria. The electronic control is additionally configured to identify each coolant branch from the multitude of coolant branches that is assigned to the selected battery module(s). The electronic control is further configured to shut off coolant flow to coolant branches not assigned to the selected battery module(s) via the flow control valve(s). Such action is intended to be taken exclusively, i.e.,excluding at least the unselected battery modules, the selected battery module(s) are heated via the coolant at an increased temperature, thereby improving the cold start discharge performance of the RESS.

[0006] The at least one selected battery module can be a single battery module.

[0007] The predetermined criteria may include determining or predicting whether the cold start discharge performance of the RESS is greater when heating at least one battery module compared to heating each of the respective battery modules.

[0008] The predetermined criteria can include a battery module state of charge (SOC) and a battery module temperature, each associated with a discharge capability of the RESS. In such an embodiment, the relevant predetermined criteria can be compiled in a lookup table programmed into the electronic control unit, which contains the battery module SOC and battery module temperature against the discharge capability of the RESS over time.

[0009] The predetermined criteria may include whether the cold start discharge capability of the RESS is below a power threshold.

[0010] After shutting off the coolant flow to coolant branches not assigned to the selected at least one battery module, the electronic control can be additionally configured to assess whether the RESS discharge power is at or above the power threshold. The electronic control can also be configured to open the coolant flow to each of the parallel coolant branches via the at least one flow control valve when the discharge power is at or above the power threshold, in order to equalize temperatures across all RESS battery modules.

[0011] Each battery module can include its own temperature sensor, which communicates with the electronic control unit and is configured to detect the temperature of the corresponding battery module. In such an embodiment, the electronic control unit can additionally be configured to use the temperature sensors to determine when the temperatures across all RESS battery modules have been equalized.

[0012] The flow control valve can be a multi-way valve assembly located in a connection between the main coolant circuit and the multiple coolant branches. Such a multi-way valve can be configured to control the flow of coolant into each of the coolant branches.

[0013] Alternatively, a number of throttle valves can regulate the flow of coolant from the main coolant circuit. Each throttle valve can be located in one of the coolant branches upstream of the corresponding battery module and configured to control the flow of coolant into that specific coolant branch.

[0014] Each coolant branch may include a one-way valve configured to control the flow of coolant from that particular coolant branch.

[0015] The cooling system may also include a fluid pump configured to circulate the coolant through the main coolant circuit.

[0016] A motor vehicle employing a system for improving the cold start discharge performance of a RESS, as described above, and a method for improving the cold start discharge performance of a RESS are also disclosed.

[0017] The above-mentioned features and advantages, as well as other features and advantages of the present disclosure, will become apparent from the following detailed description of the embodiment(s) and the best way(s) to carry out the described disclosure in conjunction with the accompanying drawings and the accompanying claims. BRIEF DESCRIPTION OF THE DRAWINGS Fig. Figure 1 is a schematic top view of an embodiment of a motor vehicle incorporating multiple power sources, a multi-cell rechargeable energy storage system (RESS) configured to generate and store electrical energy used by vehicle systems, and a system for improving the RESS cold-start discharge performance according to the disclosure. Fig. 2 is a schematic representation of the in Fig. 1 system shown for improving RESS cold start discharge performance, which includes an embodiment of a cooling subsystem with a main coolant circuit and several parallel coolant branch subsystems for adjusting the temperature in individual battery modules according to the disclosure. Fig. 3 is a schematic representation of the in Fig. 1 system shown for improving the RESS cold start discharge performance, which includes a further embodiment of the cooling part system with a main coolant circuit and several parallel coolant branch subsystems for adjusting the temperature in individual battery modules according to the disclosure. Fig. Figure 4 illustrates a method for improving cold-start discharge performance in a multi-cell RESS, which is described in Fig. 1- Fig. The coolant subsystem shown in section 3 is used. DETAILED DESCRIPTION

[0018] The embodiments of the present disclosure, as described herein, are intended to serve as examples. Other embodiments may take different and alternative forms. Furthermore, the drawings are generally schematic and not necessarily to scale. Some features may be enlarged or reduced to show details of certain components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching a person skilled in the art how the present disclosure may be used in various ways.

[0019] Specific terminology may be used in the following description for reference purposes only and is therefore not intended to be restrictive. For example, terms such as "above" and "below" refer to directions in the referenced drawings. Terms such as "front," "back," "forward," "backward," "left," "right," "back," "sideways," "upward," "downward," "above," and "below," etc., describe the orientation and / or location of parts of the components or elements within a consistent but arbitrary frame of reference, as clarified by reference to the text and the associated drawings describing the components or elements under discussion.

[0020] Furthermore, terms such as "first," "second," "third," and so on may be used to describe separate components. Such terminology may include the words expressly mentioned above, derivatives thereof, and words of similar meaning, and is used descriptively for the figures and does not constitute any limitation of the scope of disclosure as defined by the attached claims. Moreover, the teachings may be described here in the form of functional and / or logical block components and / or various processing steps. It should be recognized that such block components may include a set of hardware, software, and / or firmware components configured to perform the specified functions.

[0021] Referring to the drawings in which the same reference numerals refer to the same components, shows Fig. Figure 1 shows a schematic view of a motor vehicle 10 with 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 airplane, an all-terrain vehicle (ATV), a boat, a personal mobility device, a robot, and the like, to achieve the purposes of this disclosure. The powertrain 12 includes a power source 14 configured to deliver a power source torque T (in Fig. (1 shown) to generate power for propelling the vehicle 10 via driven wheels 16 relative to a road surface 18. The power source 14 is represented as an electric motor-generator.

[0022] As in Fig. As shown in Figure 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 power 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, which is configured to generate and store electrical energy through heat-generating electrochemical reactions for supplying the electrical energy to the power sources 14 and 20. The CPU 22 regulates various systems of the vehicle 10, including the powertrain 12, to generate a predetermined amount of power source torque T. The RESS 24 can be connected to the power sources 14 and 20, to the electronic CPU 22, and to other vehicle systems via a high-voltage data bus or BUS 25.

[0023] As in Fig. 1- Fig. As shown in Figure 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. It is specifically intended that the modules 30-1, 30-2, and 30-3 are arranged electrically in parallel. Within individual modules, e.g., 30-1, 30-2, and 30-3, different battery cells 28 can be connected electrically in series or in parallel and assembled into cell groups. Such cell groups are then connected electrically in series and assembled into individual modules. Although three individual battery modules are specifically shown, it is intended that the RESS 24 comprises at least two modules of each type, and that multiple modules can be organized into battery packs.

[0024] 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 having a desired number of battery cells 28. As in Fig. 2 and Fig. As shown in Figure 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 a chassis ground and configured to accommodate and support the corresponding battery cells 28. The RESS 24 can also include a battery pack housing 33, which is surrounded by an environment 34 and configured to support the battery modules 30-1, 30-2, 30-3 (in Fig. 1 shown) to take up and carry.

[0025] As in Fig. 2 and Fig. As shown in Figure 3, the RESS 24 also includes a cooling system 36 configured to remove heat energy from various temperature-sensitive components of the RESS. The cooling system 36 includes a main coolant circuit 38 configured to circulate a coolant 40 through the RESS 24. As shown, the cooling system 36 further includes a fluid pump 42 configured to circulate the coolant 40 through the main coolant circuit 38. The cooling system 36 also includes 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 close proximity to and along the constituent battery cells 28.

[0026] 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 can be in fluid communication with additional parallel coolant branches, for example, to circulate the coolant through various devices such as auxiliary power modules (APMs), a battery disconnect unit (BDU) containing various electrical switches and relays, electrical connectors, a DC / DC converter for supplying 12 V / 48 V power to the vehicle, etc., each of which has a specific temperature requirement. Accordingly, at least some of the coolant branches are configured to receive respective portions of the coolant 40 from the main coolant circuit 38 in order to adjust the temperature of corresponding individual battery modules 30-1, 30-2, 30-3.

[0027] With further reference to the Fig. 2 and Fig. 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, and 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 system 36. The cooling system 36 additionally includes at least one flow valve 50. The flow valve(s) 50 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, and 44-3.In other words, the flow valve(s) 50 are specifically structured and operated to provide independent regulation of the coolant flow into each individual coolant branch 44-1, 44-2, 44-3.

[0028] As in Fig. As shown in Figure 2, the flow valve 50 can be a multi-way valve assembly located in a connection, 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 assembly of the 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 Figure 2, the flow valve 50 can be a multi-way valve assembly located in a connection, 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. Fig. As shown in Figure 3, the flow valve(s) 50 can be a plurality of individual throttle valves 50-1, 50-2, 50-3. Each throttle valve 50-1, 50-2, 50-3 can be located in one of the plurality of 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 the coolant 40 into the coolant branch in question.

[0029] As in the Fig. 2 and Fig. As shown in Figure 3, each coolant branch 44-1, 44-2, 44-3 can include a corresponding 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 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 respective coolant branch 44-1, 44-2, 44-3. The cooling system 36 can also include a variety of heat exchangers arranged in the main coolant circuit 38 to change the temperature of the coolant 40.For example, one embodiment of such a heat exchanger can be a coolant cooler 54-1, for example using a refrigerant to remove heat energy from the coolant 40 in the main coolant circuit 38. Another embodiment of such a heat exchanger can be a coolant heater 54-2, for example using an electrical resistor to add heat energy to the coolant 40.

[0030] As in Fig. 1- Fig. As shown in Figure 3, the multi-cell RESS 24 can additionally include an electronic controller 56, which can either be electronically connected to the CPU 22 or be part of it. The electronic controller 56 is in operational communication with the cooling system 36, i.e., it is configured or programmed to regulate the operation of the cooling system and can be structured to manage the operation of the RESS 24 as a whole. As shown, the electronic controller 56 is in operational communication with the fluid pump 42, the flow valve(s) 50, the coolant cooler 54-1, and the coolant heater 54-2. To support the necessary management of the RESS 24 and / or the cooling system 36, the electronic controller 56 includes, in particular, a processor and accessible 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.

[0031] Non-volatile media for the electronic control 56 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 56 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. The memory of the electronic control 56 can also include a flexible disk, a hard disk, magnetic tape, another magnetic medium, a CD-ROM, a DVD, another optical medium, etc.The electronic control 56 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.

[0032] The electronic control unit 56 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 flow valve(s) 50. One or more algorithms, generally indicated by reference numeral 58, required or accessible by the electronic control unit 56, can be stored in the control unit's memory and executed automatically to facilitate the operation of the RESS 24 and / or the cooling system 36. The function of the cooling system 36 can be regulated by the electronic control unit 56 under normal operating conditions, as well as for the purpose of improving the performance of the RESS 24 under certain circumstances or transitional conditions provided herein and described in detail below.

[0033] In general, during regular operation of the RESS, the coolant flow through the coolant branches 44-1, 44-2, 44-3 is used to absorb heat energy released by the battery cells 28 in the individual battery modules 30-1, 30-2, 30-3 and to stabilize the RESS operation. Under stable operating conditions, the RESS has sufficient capacity to provide a predictable power output to operate vehicle systems, including the powertrain 12. However, during a cold start of the vehicle 10 and the RESS 24, the discharge power of the RESS may be limited because the battery cell temperature is below a certain temperature threshold 60, which is influenced by the specific battery cell chemistry and the battery's state of charge (SOC).Under certain circumstances, higher power discharge rates can be achieved in a cold-soaked, electrically parallel module-RESS 24 by increasing the temperature of at least one, but not all, of the battery modules 30-1, 30-2, 30-3. Such a result is achievable because, in an RESS with constituent modules connected electrically in parallel, each individual module is capable of supplying different electrical currents and power.

[0034] As in Fig. As shown in Figure 1, the vehicle 10 also includes a system 62 for improving or optimizing the cold-start discharge power generation of the RESS 24, and the electronic control unit 56 is programmed with one or more specific algorithms 58 to operate the system in question. In particular, the algorithm(s) 58 include an inventory mode configured to monitor ambient conditions and the temperature of the RESS 24 prior to the start of the vehicle 10 in order to assess the probability that the RESS will be requested to generate cold-start power while the coolant 40 flow is delivered to each of the coolant branches 44-1, 44-2, 44-3. The electronic control unit 56 is also configured to detect a request 64 for the cold-start discharge power of the RESS 24, such as a key-start mode of the powertrain 12.

[0035] Before the RESS 24 is requested to discharge cold-start power, the electronic control unit 56 is additionally configured to detect that the temperature of the RESS 24 is at or below a predetermined value, such as the temperature threshold 60. Each battery module 30-1, 30-2, 30-3 can include a corresponding temperature sensor 66-1, 66-2, 66-3, which communicates with the electronic control unit 56 and is configured to detect the temperature of the corresponding battery module. Signals from the temperature sensors 66-1, 66-2, 66-3 can be used to determine how the temperature of the RESS 24 compares to the temperature threshold 60. The electronic control unit 56 is also configured to raise the temperature of the coolant 40 above the temperature threshold 60 using the coolant heater 54-2 in the main coolant circuit 38.

[0036] The electronic control unit 56 is additionally configured to select at least one battery module, but fewer than all of the respective battery modules, e.g., 30-1, 30-2, 30-3, in the RESS 24 using predetermined criteria 68, which are discussed in detail below. In particular, the electronic control unit 56 can select a single battery module, such as module 30-1. The electronic control unit 56 can then identify each coolant branch from the plurality of coolant branches, e.g., 44-1, 44-2, 44-3, that is associated with the selected battery module(s), such as branch 44-1, which corresponds to module 30-1. The electronic control 56 is further configured to shut off the flow of coolant 40 in coolant branches not assigned to the selected battery module(s), or ‘unassigned branches’, such as branches 44-2, 44-3, via the flow valve(s) 50.Additionally, such unassigned coolant branches may include coolant branches intended for heating / cooling an APM, BDU, DC / DC converter or other non-battery module device in the RESS 24.

[0037] Such a coolant shutdown is intended, in particular and exclusively (i.e., excluding at least the unselected battery modules), to heat the selected battery module(s), e.g., 30-1, via the coolant at an elevated temperature 40, thereby improving the cold-crank discharge performance of the RESS 24. For example, the predetermined criteria 68 may include determining or predicting whether the cold-crank discharge performance of the RESS 24 is greater when heating a specific battery module(s) in the RESS compared to heating each of the respective battery modules 30-1, 30-2, 30-3 individually. Alternatively, during a cold start, the system 62 may maintain the flow of coolant 40 in coolant branches assigned to non-battery module device(s), while shutting off the coolant flow in coolant branch(es) of the unselected battery module(s).Such a measure would allow selected battery module(s) in the RESS 24 to be heated while providing some coolant flow for other non-battery module devices.

[0038] The predetermined criteria 68 may include parameters such as the battery module state of charge (SOC) and the battery module temperature, which are associated with the discharge capability of the RESS 24. These predetermined criteria 68 may be compiled in a lookup table 70, which is programmed into the electronic control unit 56 and which the algorithm(s) 58 accesses during system 62 operation. The lookup table 70 contains the battery module SOC and battery module temperature in relation to the discharge capability of the RESS over time, enabling the algorithm(s) 58 to select one or more battery modules to be heated in the RESS 24. The predetermined criteria 68 may also include whether the cold-cranking discharge capability of the RESS 24 is below a power threshold 72.Such a performance threshold can specify a minimum performance requirement for a cold start of the powertrain 12, as empirically determined for a particular vehicle 10 and programmed into the electronic control 56.

[0039] After the flow of coolant 40 to the unassigned coolant branch(es), e.g., 44-2, 44-3, is shut off, the electronic control 56 can request cold-start discharge power from the RESS 24, for example, to operate the powertrain 12. After the flow of coolant 40 to the unassigned branch(es) is shut off and the cold-start power generation has been triggered, the electronic control 56 can additionally be configured to assess whether the discharge power of the RESS 24 has risen to or above the power threshold 72. The electronic control 56 can then, via the flow valve(s) 50, open the flow of coolant 40 to each of the parallel coolant branches, including coolant branch 44-1, 44-2, 44-3, which supplies the respective battery modules, e.g., 44-2, 44-3. B. 30-1, 30-2, 30-3, in which RESS 24 is assigned when the discharge power reaches or exceeds the power threshold of 72.Opening each coolant branch would distribute the available heated coolant flow 40 essentially evenly over the constituent battery modules and other RESS devices, equalizing temperatures across the entire RESS 24. The electronic control 56 can then be additionally configured to determine, using the temperature sensors 66-1, 66-2, 66-3, when the temperatures across all battery modules of the RESS 24 have been equalized.

[0040] Method 100 for improving the cold start discharge performance in a multi-cell rechargeable energy storage system, such as the RESS 24, as described in Fig. As shown in 4, the following is described with reference to the information in Fig. 1- Fig. The structure shown in Figure 3 is described. The method is intended in particular for use in the RESS, which employs a main coolant circuit connected to a fluid pump, e.g., the main coolant circuit 38, and a plurality of coolant branches, e.g., branches 44-1, 44-2, 44-3, arranged in parallel, each configured to receive a portion of the coolant 40 from the main coolant circuit. The RESS in question also employs at least one flow valve 50 configured to regulate the coolant 40 received from the main coolant circuit 38 and distribute it through the plurality of coolant branches 44-1, 44-2, 44-3.

[0041] Procedure 100 begins in frame 102 with the detection, via electronic control 56, of the request 64, e.g., the key-on mode of the powertrain 12, for the cold-start discharge power of the RESS 24. After frame 102, the procedure proceeds to frame 104. In frame 104, before requesting the generation of the cold-start discharge power from the RESS 24, the procedure includes detecting, via electronic control 56, that the temperature of the RESS is at or below the temperature threshold 60. After frame 104, the procedure proceeds to frame 106. In frame 106, the procedure includes raising the temperature of the coolant 40 above the temperature threshold 60 using the coolant heater 54-2 in the main coolant circuit 38, via electronic control 56. After completion of frame 106, the procedure proceeds to frame 108.

[0042] In framework 108, the procedure involves selecting, via the electronic control 56, at least one battery module, e.g., from modules 30-1, 30-2, 30-3, but less than all of the respective battery modules, in which RESS 24 is used, according to the predetermined criteria 68. As above with regard to Fig. 1- Fig. As described in section 3, the predetermined criteria 68 can include a battery module state of charge (SOC) and a battery module temperature, which are associated with the discharge capability of the RESS 24. The lookup table 70 can be compiled using such predetermined criteria 68 and programmed into the electronic control 56 for access during operation of the system 62. The lookup table 70 includes the battery module SOC and battery module temperature versus the discharge capability of the RESS over time, which enables the algorithm(s) 58 to select the battery module(s) to be heated. The predetermined criteria 68 can also include whether the cold-crank discharge capability of the RESS 24 is below the power threshold 72. According to frame 108, the procedure proceeds to frame 110.

[0043] In frame 110, the method involves identifying, via the electronic control 56, each coolant branch from coolant branches 44-1, 44-2, and 44-3 that is assigned to the selected battery module(s). Following frame 110, the method proceeds to frame 112. In frame 112, the method involves shutting off, via the electronic control 56 and using the flow valve(s) 50, the flow of coolant 40 to coolant branches not assigned to the selected battery module(s) in order to heat the selected battery module(s) exclusively (excluding at least the unselected battery modules) via the coolant at an elevated temperature 40. As described above with respect to Fig. 1- Fig.As described in section 3, exclusively heating the selected battery module(s) via the coolant at an elevated temperature 40 is intended to improve the cold-cranking discharge performance of the RESS 24. A single battery module can be selected in the RESS 24 for such exclusive heating. According to frame 112, the procedure 100 can transition to frame 114. In frame 114, the procedure can involve requesting or triggering the generation of cold-cranking discharge power from the RESS 24, for example, to operate the powertrain 12.

[0044] Following frame 114, the procedure 100 can transition to frame 116. In frame 116, the procedure involves assessing, via the electronic control 56, whether the discharge power of the RESS 24 is at or above the power threshold 72. Following frame 116, the procedure 100 can transition to frame 118. In frame 118, the procedure involves opening, via the electronic control 56 and using the flow valve(s) 50, the flow of coolant 40 into each of the parallel coolant branches (coolant branches 44-1, 44-2, 44-3, which are assigned to the respective battery modules and coolant branches for other devices) in the RESS 24 when the discharge power is at or above the power threshold 72. Opening the flow of coolant 40 into each of the coolant branches 44-1, 44-2, 44-3 is intended to equalize temperatures across the corresponding battery modules and other devices of the RESS 24.In framework 118, the procedure may further include determining, via the electronic control 56 using the temperature sensors 66-1, 66-2, 66-3, when the temperatures across the battery modules concerned have been balanced.

[0045] After either frame 112, 114, 116, or 118, the procedure can return to frame 104 for further monitoring of the RESS 24 and for recording the temperature of the RESS to compare it with the temperature threshold 60. If the vehicle 10 continues to request power discharge from the RESS 24 and the power generation is judged to be unaffected by the combined factors of the RESS state of charge (SOC) and low temperature, the procedure can end in frame 120. Alternatively, if the powertrain 12 and other vehicle systems have been shut down 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 120.

[0046] The detailed description and the drawings or figures support and describe the disclosure, but the scope of the disclosure is defined exclusively by the claims. While some of the best ways and other embodiments for carrying out the claimed disclosure have been described in detail, there are various alternative designs and embodiments for implementing the disclosure, which are defined in the accompanying claims. Furthermore, the embodiments shown in the drawings or the features of various embodiments mentioned in this description are not necessarily to be understood as independent embodiments.Rather, it is possible that each of the features described in one of the examples of an embodiment can be combined with one or a multitude of other desired features from other embodiments, leading to other embodiments that are not described in words or by reference to the drawings. Accordingly, such other embodiments fall within the scope and extent of the appended claims.

Claims

[1] System for improving the cold start discharge performance of a multi-cell rechargeable energy storage system (RESS) with a plurality of battery cells arranged in individual battery modules connected electrically in parallel, the system comprising: a refrigeration system, including: a main coolant circuit configured to circulate coolant; a coolant heater located in the main coolant circuit; a plurality of coolant branches arranged in parallel, with at least some of the coolant branches configured to receive respective portions of the coolant from the main coolant circuit in order to adjust the temperature of corresponding individual battery modules; and at least one flow valve configured to regulate the coolant circulating through the main coolant circuit and to distribute it over the multitude of coolant branches; and an electronic control system that is in operational communication with the refrigeration system and is configured to: to detect a temperature of the RESS that is at or below a predetermined value; to increase the temperature of the coolant above the predetermined value using the coolant heater in the main coolant circuit; at least one battery module, but fewer than all of the respective battery modules, in which RESS selects using predetermined criteria; to identify each coolant branch from the multitude of coolant branches that is assigned to the selected at least one battery module; and to shut off the flow of coolant into coolant branches not assigned to the selected at least one battery module via the at least one flow valve, in order to heat the selected at least one battery module exclusively via the coolant at elevated temperature and thereby improve the cold start discharge performance of the RESS. [2] System according to claim 1, wherein the at least one selected battery module is a single battery module. [3] System according to claim 1, wherein the predetermined criteria include determining whether the cold start discharge performance of the RESS is greater when heating the at least one battery module compared to heating each of the respective battery modules. [4] System according to claim 1, wherein: the predetermined criteria include a battery module state of charge (SOC) and a battery module temperature, each of which is assigned to a discharge capability of the RESS; and the relevant predetermined criteria are compiled in a lookup table that is programmed into the electronic control system, which includes the battery module SOC and battery module temperature versus the discharge capability of the RESS over time. [5] System according to claim 1, wherein the predetermined criteria include whether the cold start discharge performance of the RESS is below a power threshold. [6] System according to claim 5, wherein after the flow of coolant to coolant branches not associated with the selected at least one battery module is shut off, the electronic control is additionally configured to: to assess whether the discharge power of the RESS is at or above the power threshold; and to open the flow of coolant into each of the parallel coolant branches via at least one flow valve when the discharge power is at or above the power threshold, in order to equalize temperatures across the entire RESS battery modules. [7] System according to claim 6, wherein: Each battery module includes a separate temperature sensor that communicates with the electronic control unit and is configured to detect the temperature of the corresponding battery module; and The electronic control is additionally configured to determine, using the temperature sensors, when the temperatures across all RESS battery modules have been balanced. [8] System according to claim 1, wherein the at least one flow valve is a multi-way valve assembly arranged in a connection between the main coolant circuit and the plurality of coolant branches and configured to control a flow of coolant into each of the coolant branches. [9] System according to claim 1, wherein the at least one flow control valve is a plurality of throttle valves, each throttle valve being arranged in one of the plurality of coolant branches upstream of the corresponding battery module and being configured to control a flow of coolant into the coolant branch concerned. [10] System according to claim 1, wherein each coolant branch includes a one-way valve configured to control a flow of coolant from the coolant branch concerned.

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