Detection and mitigation of coolant leaks in multi-branch coolant systems

Abstract

A coolant leak detection and mitigation system for a multi-cell rechargeable energy storage system (RESS) having a plurality of battery cells arranged in a separate battery module includes a cooling system. The cooling system has a main coolant circuit circulating coolant and a plurality of coolant branches arranged in parallel. Each coolant branch receives a portion of the coolant from the primary coolant circuit to remove thermal energy from one battery module. The cooling system also has one or more flow valves for regulating and distributing coolant from the main coolant circuit through the coolant branches. The leak detection and mitigation system also includes an electronic controller configured to monitor a coolant leak of the coolant branch via a coolant leak detection technique. The controller is further configured to identify a coolant branch having a coolant leak and to shut off coolant flow into the coolant branch having the coolant leak via the flow valve.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to detection and mitigation of coolant leaks in a multi-branch coolant system for a multi-cell rechargeable energy storage system (RESS). BACKGROUND

[0002] Generally, an electrical energy generation and storage battery system includes one or more battery cells for powering 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 array. Batteries can be broadly classified as primary and secondary. Primary batteries, also known as disposable batteries, are intended to be used until they are depleted, after which they are simply replaced with new batteries. Secondary batteries, more commonly referred to as rechargeable batteries, employ specific chemistries that allow such batteries to be repeatedly recharged and reused, thus offering economic, environmental, and ease-of-use benefits compared to disposable batteries.

[0003] Rechargeable batteries can be used to power a variety of items such as toys, consumer electronics, and motor vehicles. The specific chemistry of rechargeable batteries, such as lithium-ion batteries, as well as external factors can cause internal reaction rates that generate a significant amount of thermal energy. Prolonged exposure of the battery cells to elevated temperatures can cause the battery to experience a thermal runaway event in which heat builds up in a single battery cell causing heat to spread to adjacent battery cells in the module and affect the entire battery array. Therefore, it is necessary to effectively remove the thermal energy to mitigate the build-up of heat and subsequent degradation of battery system performance. Typically, devices such as heat sinks or cold plates with circulating coolant are used to remove heat from the battery system. SUMMARY

[0004] A coolant leak detection and mitigation system for a multi-cell rechargeable energy storage system (RESS) having a plurality of battery cells arranged in separate battery modules includes a cooling system. The cooling system has a main coolant loop configured to circulate a coolant and a plurality of coolant branches fluidly arranged in parallel. Each coolant branch is configured to receive a portion of the coolant from the main coolant loop to remove thermal energy from one of the respective battery modules. The cooling system further has at least one flow valve configured to regulate and distribute the coolant circulating through the main coolant loop across the plurality of coolant branches. The coolant leak detection and mitigation system further includes an electronic controller in operable communication with the cooling system. The electronic controller is configured to monitor the plurality of coolant branches for coolant leaks via at least one coolant leak detection technique. The electronic controller is further configured to identify a coolant branch having a coolant leak from the plurality of coolant branches. The electronic controller is additionally configured to shut off coolant flow into the coolant branch having the coolant leak via the flow valve.

[0005] The electronic controller can additionally be configured to set an alarm indicating that a coolant branch has a coolant leak and that the flow of coolant has been shut off.

[0006] Each battery module can include a first sensor in communication with the electronic controller and configured to detect a coolant leak via a change in electrical resistance of the first sensor. Determination of the electrical resistance of the first sensor provides a first embodiment of a coolant leak detection technique.

[0007] The coolant can include a fluorescent dye. In such embodiments, each battery module can include a second sensor in communication with the electronic controller and configured to detect a coolant leak via detection of the fluorescent dye. The second sensor thereby provides another embodiment of a coolant leak detection technique. Detection of the fluorescent dye within a battery module via the second sensor provides a second embodiment of a coolant leak detection technique.

[0008] The multi-cell RESS can be connected to a high pressure bus. In such embodiments, the electronic controller can additionally be configured to identify a coolant branch having a coolant leak via isolated measurement of electrical resistance of individual battery modules. Isolated measurement of battery module electrical resistance provides a third embodiment of a coolant leak detection technique.

[0009] The electronic controller can be configured to identify a coolant branch having a coolant leak via at least two separate coolant leak detection techniques to distinguish a coolant leak from a condensation zone inside a respective battery module housing but outside the main coolant branch.

[0010] The flow valve can be a multi-way valve assembly disposed at a junction between the main coolant circuit and the plurality of coolant branches. Such a multi-way valve can be configured to control the flow of coolant into each of the coolant branches.

[0011] Optionally, a plurality of throttle valves can regulate the flow of coolant from the main coolant circuit. Each throttle valve can be disposed in one of the coolant branches upstream of a respective battery module and configured to control the flow of coolant into the main coolant branch.

[0012] Each coolant branch can include a check valve configured to control the flow of coolant out of the main coolant branch.

[0013] The cooling system can further include a fluid pump configured to circulate coolant through the main coolant circuit.

[0014] A motor vehicle employing the coolant leak detection and mitigation system as described above is also disclosed, as is a method of detecting and mitigating coolant leaks in a multi-cell rechargeable energy storage system (RESS).

[0015] The above-mentioned and other features and advantages of the disclosure will become apparent from the following detailed description, taken in conjunction with the accompanying drawings and appended claims, when considered in conjunction with the following detailed description. BRIEF DESCRIPTION OF DRAWINGS

[0016] Figure 1 is a schematic top view of an embodiment of a motor vehicle according to the present disclosure employing a plurality of power sources and a multi-cell rechargeable energy storage system (RESS) configured to generate and store electrical energy for use by vehicle systems including the power sources.

[0017] Figure 2 is a schematic view of a multi-cell RESS according to the present disclosure Figure 1 is a schematic view of a RESS including an embodiment of a coolant system having a main coolant loop and a plurality of parallel coolant branch subsystems for removing thermal energy from individual battery modules and sensors for detecting coolant leaks within the coolant branches.

[0018] Figure 3 is a schematic view of a multi-cell RESS according to the present disclosure Figure 1 is a schematic view of a RESS including another embodiment of a coolant system having a main coolant loop and a plurality of parallel coolant branch subsystems for removing thermal energy from individual battery modules and sensors for detecting coolant leaks within the coolant branches.

[0019] Figure 4 is shown. Figures 1-3 is a method of detecting and mitigating coolant leaks in a multi-cell RESS. DETAILED DESCRIPTION

[0020] Embodiments of the present disclosure as described herein are intended to be exemplary. Other embodiments can take various and alternative forms. In addition, the figures are typically diagrammatic and not necessarily to scale. Some features can be exaggerated or minimised to show specific details. Thus, specific structural and functional details disclosed herein are not to be interpreted as limiting, but only as a representative basis for teaching one skilled in the art to variously employ the present disclosure in a variety of form.

[0021] Certain terminology can be used in the following description for the purposes of reference only, and, thus, is not intended to be limiting. For example, terms such as "above" and "below" refer to directions in the drawings to which reference is made. Terms such as "front," "back," "forward," "rear," "antecedent," "subsequent," "left," "right," "up," "down," "top," "bottom," and the like describe the orientation in the figures in which the component or element is depicted, and are not limiting. The terminology used in the description is for the purpose of describing particular embodiments only and is not intended to be limiting of the disclosure. All literature and similar materials cited in this application, including but not limited to, patents, genetic code databases, patent applications, articles, books, and treatises are expressly incorporated by reference in their entirety for any purpose.

[0022] Further, terms such as "first," "second," "third," and the like can be used to describe separate components. Such terminology can include the words specifically mentioned above, derivatives thereof, and words of similar import and is descriptive of the drawings and is not intended to limit the scope of the disclosure as defined by the appended claims. Moreover, the teachings herein can be described with respect to functional and / or logical block components and various processing steps. It should be recognized that such block components can include a number of hardware, software, and / or firmware components configured to perform the specified functions.

[0023] Referring to the drawings, wherein like reference numerals refer to like components, Figure 1 A schematic view of a motor vehicle 10 having a powertrain 12 is shown. The vehicle 10 can include, but is not limited to, a commercial vehicle, an industrial vehicle, a passenger car, an airplane, a boat, a train, etc. It is also contemplated that the vehicle 10 can be a mobile platform such as an airplane, an all-terrain vehicle (ATV), a boat, a personal mobility device, a robot, etc. to achieve the purposes of the present disclosure. The powertrain 12 includes a power source 14 configured to generate a power source torque T Figure 1 shown in FIG. 1) for propelling the vehicle 10 via driven wheels 16 relative to a road surface 18. The power source 14 is depicted as a motor-generator.

[0024] As Figure 1 shown, the powertrain 12 can include an additional power source 20, such as an internal combustion engine. The power sources 14 and 20 can act in concert to provide power to the vehicle 10. The vehicle 10 additionally 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 electrochemical reactions that generate heat to supply 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.

[0025] As Figures 1-3As shown, the RESS 24 includes a plurality of battery cells 28 arranged in separate battery packs or modules, such as a first module 30-1, a second module 30-2, and a third module 30-3. The body modules 30-1, 30-2, 30-3 can be electrically arranged in series or in parallel. Although three separate battery modules are specifically shown, it is intended that the RESS 24 include at least two respective modules, and multiple modules can be organized into battery packs or sub-packs. The remainder of this specification will focus on a RESS 24 configuration having three battery modules 30-1, 30-2, 30-3, with each battery module having a required amount of battery cells 28. As Figure 2 and Figure 3 As shown, each battery module 30-1, 30-2, 30-3 includes a respective battery module housing 32-1, 32-2, 32-3 that is connected to the chassis ground and is configured to house and support the respective battery cells 28. As Figure 1 As shown, the RESS 24 can also include a battery pack housing 33 that is surrounded by an ambient environment 34 and is configured to house and support the battery modules 30-1, 30-2, 30-3.

[0026] As Figure 2 and Figure 3 As shown, the RESS 24 also includes a cooling system 36 that is configured to remove thermal energy from various temperature sensitive components of the RESS. The cooling system 36 includes a main coolant circuit 38 that is structured to circulate a coolant 40 through the RESS 24. As shown, the cooling system 36 also includes a fluid pump 42 that is configured to circulate the coolant 40 through the main coolant circuit 38. The cooling system 36 also includes a plurality of coolant branches in fluid communication with the main coolant circuit 38, shown as a first branch 44-1, a second branch 44-2, and a third branch 44-3. Each of the coolant branches 44-1, 44-2, 44-3 extends through the respective battery module 30-1, 30-2, 30-3 proximate to and along the constructed battery cells 28.

[0027] Further, each coolant branch 44-1, 44-2, 44-3 is configured to receive a portion of coolant 40 from the main coolant circuit 38. The coolant branches 44-1, 44-2, 44-3 are fluidly arranged in parallel to receive respective portions of the coolant 40. Thus, the coolant branches 44-1, 44-2, 44-3 are thereby configured to independently circulate their respective portions of the coolant 40 and regulate the temperature of the respective battery module 30-1, 30-2, 30-3 (by removing or adding thermal energy). Thus, 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 coolant through auxiliary power modules (APMs), battery disconnect units (BDUs) including various electrical switches and relays, electrical connectors, DC / DC converters for supplying 12V / 48V electrical power to the vehicle, etc., each having specific temperature requirements.

[0028] With continued reference to Figure 2 and Figure 3 , the RESS 24 can further 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. Thus, the inlet manifold 46 and the outlet manifold 48 together are structured to maintain circulation of the coolant 40 through the cooling system 36. The cooling system 36 additionally includes at least one flow valve 50. The flow valve 50 is configured to regulate and distribute the coolant 40 circulating through and received from the main coolant circuit 38 across the individual coolant branches 44-1, 44-2, 44-3. In other words, the flow valve 50 is specifically structured and operated to provide independent regulation of the flow of coolant into each individual coolant branch 44-1, 44-2, 44-3.

[0029] As Figure 2 shown, the flow valve 50 can be a multi-way valve assembly arranged in the junction (e.g., 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 multi-way valve assembly embodiment 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 Figure 3As shown, flow valve 50 can be a plurality of individual throttling valves 50-1, 50-2, 50-3. Each body throttling valve 50-1, 50-2, 50-3 can be disposed in one of the plurality of coolant branches 44-1, 44-2, 44-3 upstream of a respective battery module 30-1, 30-2, 30-3 and configured to control the flow of coolant 40 into the body coolant branch.

[0030] As shown in Figure 2 and Figure 3 Each coolant branch 44-1, 44-2, 44-3 can include a respective check valve 52-1, 52-2, 52-3, as shown. Check valves 52-1, 52-2, 52-3 are configured to prevent backflow of coolant 40 into the respective coolant branch 44-1, 44-2, 44-3. Each of check valves 52-1, 52-2, 52-3 is disposed downstream of flow valve 50 and a respective battery module 30-1, 30-2, 30-3. Accordingly, each check valve 52-1, 52-2, 52-3 is configured to control the flow of a respective portion of coolant 40 through and out of the body coolant branch 44-1, 44-2, 44-3. Cooling system 36 can also include a plurality of heat exchangers disposed in main coolant loop 38 to vary the temperature of coolant 40. One embodiment of such a heat exchanger can be a coolant chiller 54-1, for example, that uses a refrigerant to remove heat energy from coolant 40 in main coolant loop 38. Another embodiment of such a heat exchanger can be a coolant heater 54-2, for example, that uses electrical resistance to add heat energy to coolant 40.

[0031] As shown in Figure 2 and Figure 3 Multi-cell RESS 24 can additionally include an electronic controller 56, which can be electrically connected to or part of CPU 22. Electronic controller 56 can be configured or programmed to regulate the operation of cooling system 36 or configured to manage the operation of RESS 24 as a whole. As shown, electronic controller 56 is in operable communication with fluid pump 42, flow valve 50, coolant chiller 54-1, and coolant heater 54-2. To support the necessary management of RESS 24 and / or cooling system 36, electronic controller 56 specifically includes a processor and a tangible non-transitory memory including necessary instructions programmed therein. The memory of the controller can be an appropriate recordable medium involved in providing computer-readable data or process instructions. Such recordable media can take many forms, including but not limited to non-volatile and volatile media.

[0032] Non-volatile media for the electronic controller 56 can include, for example, optical or magnetic disks and other persistent memory. Volatile media can include, for example, dynamic random access memory (DRAM), which can constitute main memory. Instructions programmed into the controller 56 can be transmitted by one or more transmission media, including coaxial cables, copper wire, and optical fiber including the wires that comprise a system bus coupled to a processor of a computer, or transmitted via a wireless connection. Memory of the electronic controller 56 can also include a floppy disk, a hard disk, a tape, another magnetic medium, a CD-ROM, a DVD, another optical medium, etc. The electronic controller 56 can be configured or equipped with other required computer hardware, such as a high-speed clock, necessary analog-to-digital (A / D) and / or digital-to-analog (D / A) circuitry, input / output circuitry and devices (I / O), and appropriate signal-conditioning and / or buffer circuitry.

[0033] The electronic controller 56 can be configured to regulate the flow of coolant 40 into the individual battery modules 30-1, 30-2, 30-3 via the fluid pump 42 and the flow valve 50. Algorithms required by or accessible to the electronic controller 56 (generally indicated by reference numeral 58) can be stored in the memory of the controller and executed automatically to facilitate operation of the RESS 24 and / or the cooling system 36. In particular, the algorithms 58 include an inventory mode configured to monitor coolant leaks in the plurality of coolant branches 44-1, 44-2, 44-3 via at least one coolant leak detection technique or subroutine. One or more individual detection techniques indicated via reference numerals 60-1, 60-2, and 60-3 and described below can be programmed into the electronic controller 56 for monitoring coolant leaks in the coolant branches 44-1, 44-2, 44-3. Coolant leaks in the coolant branches 44-1, 44-2, 44-3 can be monitored or evaluated continuously, at regular time intervals, or upon each key-on of the vehicle 10. As will become apparent below, the individual detection techniques 60-1, 60-2, 60-3 focus on monitoring the individual battery modules 30-1, 30-2, 30-3 inside the respective battery module housings 32-1, 32-2, 32-3 but outside the actual coolant branches 44-1, 44-2, 44-3.

[0034] The electronic controller 56 is also configured to identify coolant branches affected by coolant leaks from branches 44-1, 44-2, and 44-3. For example, coolant branch 44-1 can be identified as having a leak. The controller 56 is also programmed to cut off the flow of coolant 40 into the coolant branch (e.g., branch 44-1) with a coolant leak via flow valve 50. For example, a multi-way valve 50 or a throttle valve 50-1 can be used to cut off the coolant flow to branch 44-1. The electronic controller 56 can be additionally configured to set (i.e., command or trigger) an alarm 62 indicating that a coolant branch has a coolant leak and that coolant flow to that branch has been cut off. In other words, alarm 62 can notify the system user or technician directly via a sensing signal or fault code or via a remote server (not shown) that a specific coolant branch is damaged and that coolant flow through it has been blocked.

[0035] like Figure 2 As shown, each battery module 30-1, 30-2, 30-3 may include a corresponding first sensor 64-1, 64-2, 64-3 communicating with the electronic controller 56. Each first sensor 64-1, 64-2, 64-3 is arranged outside the corresponding coolant branch 44-1, 44-2, 44-3, inside the corresponding battery module housing 32-1, 32-2, 32-3, for example, near the housing tray (not shown), where leaked coolant may accumulate. Coolant leakage in a specific branch 44-1, 44-2, 44-3 can be detected by changes in the resistance of the corresponding first sensor 64-1, 64-2, 64-3. The presence of a sufficient amount of coolant 40 on the first sensor 64-1, 64-2, 64-3 will create a short circuit between the sensor terminals and significantly reduce the effective resistance of the main sensor. This reduction in the resistance of the first sensor can then be used as a first coolant leakage detection technique 60-1 (e.g., Figure 2 (As shown) is transmitted to the electronic controller 56.

[0036] Alternatively, coolant 40 may include a fluorescent dye. For example... Figure 3As shown, each battery module 30-1, 30-2, 30-3 can include a respective second sensor 66-1, 66-2, 66-3 disposed outside the respective coolant branch 44-1, 44-2, 44-3 and in communication with the electronic controller 56. Each second sensor 66-1, 66-2, 66-3 can be, for example, an ultraviolet (UV) light emitting lamp configured to detect the presence of a fluorescent dye outside the respective coolant branch 44-1, 44-2, 44-3 but inside the respective battery module housing 32-1, 32-2, 32-3 as an indicator of a coolant leak therein. Each second sensor 66-1, 66-2, 66-3 can be disposed within the respective battery module 30-1, 30-2, 30-3 to more effectively detect where coolant can collect, for example, near the housing tray. Detection of the fluorescent dye is communicated by the respective second sensor 66-1, 66-2, 66-3 to the electronic controller 56 as a second coolant leak detection technique 60-2 (as shown in FIG. 6). Figure 3

[0037] The electronic controller 56 can additionally be programmed to identify the coolant branch 44-1, 44-2, and / or 44-3 having a coolant leak via isolated measurement of the resistance of the individual battery modules. Isolated measurement can be implemented by the respective switches 70-1, 70-2, 70-3 shown in FIGS. 7 and 8. Figure 2 and Figure 3 The main body isolated measurement includes sequentially connecting one of the battery modules 30-1, 30-2, 30-3 to the high voltage bus 25 while disconnecting the remaining battery modules from the bus via the respective switches 70-1, 70-2, 70-3, then repeating the same operation for the other modules. In other words, the electronic controller 56 connects each battery module 30-1, 30-2, 30-3 one at a time to the high voltage bus 25.

[0038] When one of the battery modules 30-1, 30-2, 30-3 is connected, the resistance of the respective module 30-1, 30-2, or 30-3 will be determined using the circuit of the main body module connected to the high voltage bus 25. The electronic controller 56 can be programmed with a threshold 72 of the resistance characteristic of a dry battery module. The presence of a significant amount of coolant 40 on the battery module terminals will decrease the resistance of the battery module, and can even create a short circuit. Thus, the resulting resistance of a battery module having a coolant leak will drop below the threshold 72. Accordingly, as a third coolant leak detection technique 60-3, the isolated measured resistance of each battery module 30-1, 30-2, 30-3 can be determined and compared to the threshold 72.

[0039] ​The electronic controller 56 can be configured to perform at least two of the three coolant leak detection techniques 60-1, 60-2, 60-3 to identify a coolant branch 44-1, 44-2, 44-3 affected by a coolant leak. This repeated or confirmed coolant leak detection can be used to verify or ensure the confidence of the results before commanding a stop of coolant flow through the suspect branch. For example, the electronic controller 56 can be programmed to run coolant leak detection techniques 60-1 and 60-2 (as shown in Figure 2 ) or 60-2 and 60-3 (as shown in Figure 3 ). Specifically, the use of two or more separate coolant leak detection techniques in the cooling system 36 is intended to help differentiate between a coolant leak and condensation inside the battery module enclosure 32-1, 32-2, 32-3 but outside the respective coolant branch. Thus, the detection technique 60-2 can be used to confirm a leak assessment, as condensation would not trigger the sensor 66-1, 66-2, 66-3.

[0040] In addition to monitoring the individual coolant branches 44-1, 44-2, 44-3, the electronic controller 56 can be configured to detect the presence of a coolant leak in the RESS cooling system 36 via communication with appropriate sensors. The presence of a coolant leak in the RESS cooling system 36 can be detected by assessing a drop in fluid pressure or flow in the main coolant loop 38 or a drop in coolant reservoir level. Other methods of detecting the presence of a coolant leak in the RESS cooling system 36 can, for example, focus on identifying temperature values outside a predicted coolant temperature range downstream of the coolant branch 44-1, 44-2, 44-3, an inappropriate change in temperature of components also cooled by the coolant 40, or an inappropriate one-way valve 52-1, 52-2, 52-3 response. Monitoring of the individual coolant branches 44-1, 44-2, 44-3 can be initiated based on such detection of a coolant leak within the main coolant loop 38 or the entire cooling system 36. In the event that a coolant leak is detected in the cooling system 36 but no coolant leak is identified in the coolant branch 44-1, 44-2, 44-3, the electronic controller 56 can additionally be configured to shut down operation of the fluid pump 42 and trigger a corresponding alarm.

[0041] A method 100 of detecting and mitigating coolant leaks in a multi-cell rechargeable energy storage system, such as the RESS 24, as shown in Figure 4 and described below with reference to Figures 1-3The structure shown is described. The method is particularly useful in a RESS that employs a main coolant loop connected to a fluid pump, such as main coolant loop 38, and a plurality of coolant branches, such as branches 44-1, 44-2, 44-3 arranged in parallel, each configured to receive a portion of coolant 40 from the main coolant loop. The present RESS also employs at least one flow valve 50 configured to regulate and distribute coolant 40 received from main coolant loop 38 through the plurality of coolant branches 44-1, 44-2, 44-3.

[0042] Method 100 begins in block 102, where flow of coolant 40 in main coolant loop 38 is regulated via electronic controller 56. After block 102, the method proceeds to block 104. In block 104, the method includes monitoring coolant leaks in coolant branches, such as branches 44-1, 44-2, 44-3, in cooling system 36 via electronic controller 56 using one or more of techniques 60-1, 60-2, 60-3. According to the method, as a first coolant leak detection technique 60-1, electronic controller 56 can detect coolant leaks via identification of a change in resistance of a respective first sensor 64-1, 64-2, 64-3. As a second coolant leak detection technique 60-2, controller 56 can also detect coolant leaks using second sensors 66-1, 66-2, 66-3 by identifying the presence of fluorescent dye within a particular battery module enclosure 32-1, 32-2, 32-3 but outside of a respective coolant branch 44-1, 44-2, 44-3. According to the method, electronic controller 56 can additionally employ the isolated measurement of individual battery module resistance 68 described above with respect to Figures 2 to 3

[0043] After block 104, the method proceeds to block 106. In block 106, the method includes regulating coolant flow from the plurality of coolant branches, such as branches 44-1, 44-2, 44-3, via electronic controller 56, in response to the coolant leak detection. According to the method, as a first coolant flow regulation technique 70-1, electronic controller 56 can regulate coolant flow from the plurality of coolant branches by adjusting a flow rate of coolant 40 in main coolant loop 38. As a second coolant flow regulation technique 70-2, controller 56 can also regulate coolant flow from the plurality of coolant branches by adjusting a flow rate of coolant 40 in a particular coolant branch, such as branch 44-1, 44-2, 44-3. Figures 2-3 ​The described branch 44-1, 44-2, 44-3) is identified as having a coolant leak. According to this method, the electronic controller 56 can be programmed to identify the coolant branch affected by a coolant leak through at least two separate coolant leak detection techniques (in techniques 60-1, 60-2, and 60-3) to distinguish between an actual coolant leak and condensation within the battery module enclosure 32-1, 32-2, 32-3. Thus, after block 106 is completed, the method can move to block 108 or run another of the three leak detection techniques on the identified coolant branch to confirm that it was identified as leaking. If the results of the two techniques are consistent, the method proceeds to block 108. If the results of the two techniques are not consistent, the method can loop back to block 104 to resume monitoring of the coolant branches 44-1, 44-2, 44-3.

[0044] In block 108, the method includes shutting off the flow of coolant 40 into the coolant branch 44-1, 44-2, or 44-3 identified as being affected by a coolant leak via the flow valve 50 regulated by the electronic controller 56. After block 108, the method can proceed to block 110. In block 110, after shutting off the flow of coolant into the coolant branch affected by the leak, the method includes setting an alarm 62 via the electronic controller 56 that signals that a coolant leak is detected. The alarm 62 can identify the affected coolant branch and / or the fact that the flow of coolant has been shut off. After block 108 or block 110, the method can loop back to block 104 to continue monitoring the coolant branches 44-1, 44-2, 44-3. Otherwise, if the electrical load on the RESS 24 has been removed, for example, the vehicle 10 has been stopped, the power sources 14 and 20 have been turned off, and the fluid pump 42 has been deactivated, the method can end in block 112.

[0045] The detailed description and accompanying drawings or figures are supportive and descriptive of the disclosure, but the scope of the disclosure is defined solely by the claims. While there have been described herein the principles and various embodiments of some of the best modes and other embodiments for performing the disclosed disclosure, it is to be understood that various alterations and modifications can be made in the practice of the disclosure as defined by the claims. In addition, the embodiments illustrated and / or mentioned in the description or the accompanying drawings are not necessarily to be construed as independent embodiments. Rather, it is possible that each feature described in one of the examples of the embodiments can be combined with one or more other desirable features from other embodiments, resulting in other embodiments not described in words or with reference to the drawings. Accordingly, such other embodiments fall within the framework and scope of the appended claims.

Claims

1. A coolant leak detection and mitigation system for a multi-cell rechargeable energy storage system (RESS), the multi-cell rechargeable energy storage system having multiple battery cells arranged in individual battery modules, the coolant leak detection and mitigation system comprising: Cooling system, the cooling system comprising: A main coolant circuit, the main coolant circuit being configured to circulate coolant; Multiple coolant branches arranged in parallel, wherein each coolant branch is configured to receive a portion of the coolant from the main coolant circuit to regulate the temperature of one of the battery modules in its respective battery module; and At least one flow valve, the at least one flow valve being configured to regulate and distribute the coolant circulating through the main coolant circuit on the plurality of coolant branches; and An electronic controller, which is operatively in communication with the cooling system and configured to: The coolant leakage of the multiple coolant branches is monitored using at least one coolant leakage detection technology; Identify the coolant branch with a coolant leak from the plurality of coolant branches; and The coolant flow entering the coolant branch with the coolant leakage is cut off via the at least one flow valve.

2. The coolant leak detection and mitigation system according to claim 1, wherein, The electronic controller is also configured to set an alarm indicating that the coolant branch has a coolant leak and that the coolant flow has been cut off.

3. The coolant leak detection and mitigation system of claim 1, wherein each battery module includes a first sensor that communicates with the electronic controller and is configured to detect coolant leaks via a change in resistance of the first sensor as a first coolant leak detection technique.

4. The coolant leak detection and mitigation system according to claim 1, wherein, The coolant includes a fluorescent dye, and each battery module includes a second sensor that communicates with the electronic controller and is configured as a second coolant leak detection technology to detect coolant leaks by detecting the fluorescent dye.

5. The coolant leak detection and mitigation system according to claim 1, wherein, The multi-unit RESS is connected to a high-voltage bus, and the electronic controller is also configured to identify coolant branches with coolant leaks via isolated measurements of the resistance of the respective battery modules, as a third coolant leak detection technology.

6. The coolant leak detection and mitigation system according to claim 1, wherein, The electronic controller is configured to identify coolant branches with coolant leaks using at least two separate coolant leak detection technologies, in order to distinguish coolant leaks from condensation inside the corresponding battery module housing but outside the main coolant branch.

7. The coolant leak detection and mitigation system according to claim 1, wherein, The at least one flow valve is a multi-way valve assembly arranged at the junction between the main coolant circuit and the plurality of coolant branches, and configured to control the flow rate of coolant entering each coolant branch.

8. The coolant leak detection and mitigation system according to claim 1, wherein, The at least one flow valve is a plurality of throttle valves, each throttle valve being arranged in one of the plurality of coolant branches upstream of the respective battery module and configured to control the flow rate of the coolant into the main coolant branch.

9. The coolant leak detection and mitigation system according to claim 1, wherein, Each coolant branch includes a one-way valve configured to control the flow of coolant out of the main coolant branch.

10. A method for detecting and mitigating coolant leakage in a multi-cell rechargeable energy storage system (RESS), the multi-cell rechargeable energy storage system having a plurality of battery cells arranged in individual battery modules, the method comprising: The cooling system is monitored for coolant leakage via an electronic controller using at least one coolant leak detection technology, wherein the cooling system comprises: A main coolant circuit, the main coolant circuit being configured to circulate coolant; Multiple coolant branches arranged in parallel, wherein each coolant branch is configured to receive a portion of the coolant from the main coolant circuit to regulate the temperature of one of the battery modules in its respective battery module; and At least one flow valve, the at least one flow valve being configured to regulate and distribute the coolant circulating through the main coolant circuit on the plurality of coolant branches; The electronic controller identifies the coolant branch with a coolant leak from the plurality of coolant branches; and The coolant flow entering the coolant branch with the coolant leakage is cut off via the at least one flow valve.

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