DETECTION AND CONTAINMENT OF COOLANT LEAKS IN A MULTI-STAGE COOLING SYSTEM
Patent Information
- Authority / Receiving Office
- DE · DE
- Patent Type
- Patents
- Current Assignee / Owner
- GM GLOBAL TECHNOLOGY OPERATIONS LLC
- Filing Date
- 2024-07-10
- Publication Date
- 2026-06-25
Smart Images
Figure 00000000_0000_ABST
Abstract
Description
INTRODUCTION The present description relates to the detection and containment of coolant leaks in a multi-branch cooling system for a multi-cell rechargeable energy storage system (RESS). A battery system for generating and storing electrical energy typically includes one or more battery cells to power a load. Multiple battery cells can be arranged in close proximity to each other to form a battery module, and multiple battery modules can be organized into a battery pack array. Batteries can be broadly divided into primary and secondary batteries. Primary batteries, also known as disposable batteries, are designed to be used until depleted and then simply replaced with new ones. Secondary batteries, commonly referred to as rechargeable batteries, utilize a special chemistry that allows them to be repeatedly recharged and reused, offering economic, environmental, and user-friendliness advantages compared to disposable batteries. Rechargeable batteries can be used to power a wide variety of items, from toys and consumer electronics to motor vehicles. Certain chemical properties of rechargeable batteries, such as lithium-ion cells, as well as external factors, can lead to internal reaction rates that generate significant amounts of thermal energy. If a battery cell is exposed to high temperatures for an extended period, thermal runaway can occur, in which heat from a single cell spreads to neighboring cells in the module, affecting the entire battery assembly. Accordingly, the thermal energy must be effectively dissipated to reduce heat buildup and the resulting performance degradation of the battery system. Generally, devices such as heat sinks or cooling plates with circulating coolant are used to remove heat from battery systems. WO 2017 / 148 869 A1 shows a fuel cell system with several fuel cell modules, each with inlets and outlets for hydrogen and oxygen, and connected in separate circuits. Sensors at the outlets detect impurities and control valves to disconnect affected modules from the circuits when a threshold is exceeded. DE 10 2015 220 095 B3 describes a cooling system for vehicle components comprising a pump, a piping system with a coolant line, a sensor for detecting coolant losses, and a control unit for regulating the coolant flow. A shut-off valve upstream of the component allows for the targeted interruption of the coolant flow in the event of a detected leak. DESCRIPTION The object of the invention is to provide a cooling system for a multi-cell energy storage system that enables reliable and targeted detection and limitation of coolant leaks in individual coolant branches in order to increase the operational safety of the overall system and to avoid damage to the battery modules due to coolant leakage. This problem is solved by the subject matter according to claim 1. Further developments can be found in the dependent claims. A coolant leak detection and mitigation system for a multi-cell rechargeable energy storage system (RESS) with a multitude of battery cells arranged in individual battery modules includes a cooling system. The cooling system has a main coolant circuit configured for coolant circulation. The cooling system also has multiple coolant branches arranged fluidically in parallel. Each coolant branch is configured to draw a portion of the coolant from the main coolant circuit to regulate the temperature of one of the respective battery modules. The cooling system also includes at least one flow valve configured to regulate the coolant circulating through the main coolant circuit and distribute it to the multiple coolant branches. The leak detection and mitigation system also includes an electronic control unit configured to monitor the cooling system for a coolant loss indication. The control unit is further configured to examine each of the multiple coolant branches for a coolant leak in response to a coolant loss indication. The control unit is also configured to identify a coolant branch from among the multiple coolant branches that has a coolant leak. The control unit is further configured to shut off coolant flow to the coolant branch with the leak via the flow control valve(s). The electronic control unit can also be configured to trigger an alarm indicating that the coolant branch has a coolant leak and the flow of coolant has been interrupted. The main coolant circuit can include a reservoir configured for coolant supply and featuring a coolant level sensor connected to the electronic control unit. In such an embodiment, a coolant loss in the cooling system can be indicated by a decrease in the coolant level or volume in the reservoir. The electronic control unit can be configured to check each of the multiple coolant branches for a coolant leak by detecting the loss of coolant pressure in each corresponding coolant branch. The detection of coolant pressure loss in each coolant branch can be achieved by measuring the coolant pressure in a single coolant branch upstream of the respective battery module and determining the coolant pressure in the relevant coolant branch downstream of the relevant battery module. Each coolant branch can contain a one-way valve configured to control the coolant flow from that branch and communicated with the electronic control unit. In such an embodiment, the detection of coolant pressure loss in each coolant branch can be achieved by detecting the coolant pressure in a single coolant branch upstream of the respective battery module and determining the response of a corresponding one-way valve to the detected coolant pressure upstream of that battery module. Each coolant branch can contain a valve displacement sensor connected to the electronic control unit. In such an embodiment, the response of each one-way valve can be determined via the valve displacement sensor. The electronic control unit can be programmed using a lookup table that specifies the adjustment of the corresponding check valve depending on the coolant pressure in a single coolant branch upstream of the respective battery module. The cooling system may also include a liquid pump configured to circulate the coolant through the main coolant circuit. Each coolant branch can include a coolant flow sensor downstream of the corresponding battery module and in conjunction with the electronic control unit. In such an embodiment, the electronic control unit can further be configured to check each of the multiple coolant branches for a coolant leak by determining the amount of coolant flowing through it using the corresponding coolant flow sensor. The flow control valve can be a multi-way valve assembly located at a connection between the main coolant circuit and the various coolant branches. Such a multi-way valve can be configured to control the flow of coolant into each of the coolant branches. 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. A motor vehicle that uses a coolant leak detection and mitigation system as described above, and a method for detecting and mitigating a coolant leak in a multi-cell rechargeable energy storage system (RESS) are also disclosed. The above features and advantages, as well as other features and advantages of the present disclosure, will be readily apparent from the following detailed description of the embodiment(s) and the best embodiment(s) of the disclosed disclosure in conjunction with the accompanying figures and claims. BRIEF DESCRIPTION OF THE FIGURES Fig. 1 is a schematic top view of a motor vehicle with multiple energy sources and a multi-cell rechargeable energy storage system (RESS) configured to generate and store electrical energy used by motor vehicle systems, including the energy sources as described. Fig. 2 is a schematic representation of the RESS shown in Fig. 1, including an embodiment of a coolant system with a main coolant circuit and multiple parallel coolant branches as a subsystem for dissipating thermal energy from individual battery modules and individual coolant pressure sensors for detecting coolant leaks within the coolant branches as described. Fig. 3 is a schematic representation of the RESS shown in Fig. 1.Figure 1 shows the RESS, including a further embodiment of a coolant system with a main coolant circuit and several parallel coolant branches as a subsystem for dissipating thermal energy from individual battery modules and individual coolant flow sensors for detecting coolant leaks within the coolant branches as described. Figure 4 illustrates a method for detecting and limiting a coolant leak in the multi-cell RESS shown in Figures 1-3. DETAILED DESCRIPTION The embodiments described herein are to be understood 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 exaggerated or reduced in size to show details of certain components. Therefore, specific structural and functional details disclosed herein are not to be understood as limiting, but merely as a representative basis to show a person skilled in the art how to apply the present description in various ways. Certain terms are used in the following description for reference purposes only and should therefore not be interpreted as limitations. For example, terms such as "top" and "bottom" refer to directions in the referenced drawings. Terms such as "front," "back," "forward," "backward," "left," "right," "sideways," "top," "bottom," "upward," and "downward," etc., describe the orientation and / or position of parts of the components or elements within a uniform but arbitrary frame of reference, which becomes clear by referring to the text and the associated drawings in which the components or elements in question are described. Furthermore, terms such as "first," "second," "third," etc., may be used to describe individual components. This terminology may include the words expressly mentioned above, their derivatives, and words of similar meaning, and is used descriptively for the figures. It does not constitute a 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 clear that such block components may comprise a set of hardware, software, and / or firmware components configured to perform the specified functions. Fig. 1 shows a schematic view of a motor vehicle 10 with a powertrain 12, where identical reference numbers refer to identical components. The motor vehicle 10 can be, but is not limited to, a commercial vehicle, an industrial vehicle, a passenger vehicle, an aircraft, a watercraft, a train, or the like. It is also conceivable that the motor vehicle 10 is a mobile platform, such as an aircraft, an all-terrain vehicle (ATV), a boat, a personal mobility device, a robot, or the like, to serve 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 motor vehicle 10 via driven wheels 16 relative to a road surface 18. The power source 14 is represented as an electric motor-generator. As shown in Fig. 1, the powertrain 12 can include an additional energy source 20, such as an internal combustion engine. The energy sources 14 and 20 can work together to power the vehicle 10. The vehicle 10 also includes a central processing unit (CPU) 22 and a rechargeable multi-cell energy storage system (RESS) 24, which is configured to generate and store electrical energy through heat-generating electrochemical reactions to supply the electrical energy to the energy sources 14 and 20. The CPU 22 controls various systems of the vehicle 10, including the powertrain 12, to generate a predetermined torque T from the power source. 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. As shown in Figures 1-3, the RESS 24 comprises a plurality of battery cells 28 arranged in individual battery groups or 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, 30-3 in question can be arranged electrically in series or in parallel. Although three individual battery modules are specifically shown, it is intended that the RESS 24 comprises at least two such modules, and several modules can be organized into battery packs or subpacks. 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 shown in Figures 2 and 3, the RESS 24 comprises three battery modules 30-1, 30-2, 30-3, each of which has a desired number of battery cells 28.As shown in Figure 3, each battery module 30-1, 30-2, 30-3 comprises a corresponding battery module housing 32-1, 32-2, 32-3, which is connected to the chassis ground and configured to accommodate and support the corresponding battery cells 28. The RESS 24 may also comprise a battery housing 33, which is surrounded by an environment 34 and configured to accommodate the battery modules 30-1, 30-2, 30-3 (shown in Figure 1). As shown in Figures 2 and 3, the RESS 24 also includes a cooling system 36 configured to dissipate 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, which are in fluid communication with the main coolant circuit 38. Each of the coolant branches 44-1, 44-2, 44-3 extends through a corresponding battery module 30-1, 30-2, 30-3 near and along the associated 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 in parallel to receive corresponding portions of the coolant 40. The coolant branches 44-1, 44-2, 44-3 are configured to independently circulate their respective portions of the coolant 40 and regulate the temperature of the corresponding battery modules 30-1, 30-2, 30-3 (by removing or supplying 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 fluidically connected to additional parallel coolant branches, e.g., to circulate the coolant through auxiliary power modules (APMs), a battery disconnect unit (BDU) with various electrical switches and relays, electrical connectors, a DC / DC converter to supply the vehicle with 12 V / 48 V, etc., each of which has a specific temperature requirement. With further reference to Figures 2 and 3, the RESS 24 can also include an inlet distributor 46 configured to connect the main coolant circuit 38 to the coolant branches 44-1, 44-2, 44-3, and an outlet distributor 48 configured to reconnect the coolant branches to the main coolant circuit. Accordingly, the inlet and outlet distributors 46 and 48 together are designed to maintain the 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(s) 50 is (are) configured to regulate (regulate) the coolant 40 that circulates through and is received by the main coolant circuit 38 and to distribute (distribute) it to the individual coolant branches 44-1, 44-2, 44-3.In other words, the flow valve(s) 50 is / are specifically designed and operated in such a way as to allow independent control of the coolant flow into each individual coolant branch 44-1, 44-2, 44-3. As shown in Fig. 2, the flow valve 50 can be a multi-way valve arranged in a connection, such as the inlet manifold 46, between the main coolant circuit 38 and the multiple coolant branches 44-1, 44-2, 44-3 upstream of each battery module 30-1, 30-2, 30-3. The multi-way valve arrangement 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 Fig. 3, the flow valve(s) 50 can be a plurality of individual throttle valves 50-1, 50-2, 50-3. Each individual throttle valve 50-1, 50-2, 50-3 can be arranged in one of the several coolant branches 44-1, 44-2, 44-3 upstream of the corresponding battery module 30-1, 30-2, 30-3 and configured to control the flow of coolant 40 into the coolant branch in question. As shown in Figures 2 and 3, each coolant branch 44-1, 44-2, 44-3 can contain a corresponding one-way valve 52-1, 52-2, 52-3. The check 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 check 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 may also include a plurality of heat exchangers arranged in the main coolant circuit 38 to modify the temperature of the coolant 40.One embodiment of such a heat exchanger can be, for example, a coolant cooler 54-1, which uses a refrigerant to remove thermal 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, which, for example, uses an electrical resistor to supply heat energy to the coolant 40. As shown in Figures 2 and 3, the multi-cell RESS 24 can additionally include an electronic control unit 56, which can either be electronically connected to or part of the CPU 22. The electronic control unit 56 can be configured or programmed to regulate the operation of the cooling system 36, or it can be designed to control the operation of the RESS 24 as a whole. As shown, the electronic control unit 56 is operationally connected to the liquid 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 control unit 56 includes, in particular, a processor and tangible, non-transferable memory in which the required instructions are programmed.The memory of the control unit 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 unit 56 may include, for example, optical or magnetic disks and other permanent storage media. Volatile media may include, for example, dynamic random-access memory (DRAM), which may constitute main memory. The instructions programmed into the control unit 56 may be transmitted via one or more transmission media, including coaxial cable, copper wire, and fiber optic cable, including lines that have a system bus coupled to a computer processor, or via a wireless connection. The memory of the electronic control unit 56 may 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 unit 56 may be configured or equipped with other necessary computer hardware, such as...with a high-speed clock generator, the 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 unit 56 can be configured to regulate the flow of coolant 40 into the individual battery modules 30-1, 30-2, 30-3 via the liquid pump 42 and the flow valve(s) 50. The algorithm(s) required by or accessible to 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 algorithm(s) 58 includes, in particular, an inventory mode configured to monitor the quantity of coolant 40 present in the cooling system 36 during operation of the RESS 24. For example, a measurable depletion of coolant 40 in the main coolant circuit 38 can be used as an indication of coolant loss somewhere in the cooling system 36. As shown in Figures 2-3, the main coolant circuit 38 can include a reservoir 60 configured to supply the liquid pump 42 with the coolant 40. The reservoir 60 can contain a coolant level sensor 60A, which is connected to the electronic control unit 56. A measurable or significant drop in the coolant level or volume in the reservoir 60 can indicate a coolant loss in the coolant system 36. The coolant level sensor 60A can continuously or periodically transmit the level of the coolant 40 in the reservoir 60 to the electronic control unit 56, and the control unit 56 can determine, based on the sensor signal, whether coolant has been lost. In response to a detected coolant loss in the main coolant circuit 38, the electronic control unit 56 can initiate a check of the individual coolant branches 44-1, 44-2, 44-3 for a coolant leak.The coolant branches 44-1, 44-2, 44-3 can be continuously monitored or checked for coolant leaks, at regular intervals or each time the motor vehicle 10 is switched on. The electronic control unit 56 is specifically programmed to identify one or more coolant branches from the branches present in the cooling system 36, e.g., branches 44-1, 44-2, and 44-3, that are affected by a coolant leak. For example, coolant branch 44-1 may be detected as having a coolant leak. In such a case, the control unit 56 shuts off the flow of coolant 40 to the coolant branch with the detected leak via the corresponding flow control valve(s) 50. In this case, the coolant flow to branch 44-1 can be shut off via the multi-way valve 50 or the throttle valve 50-1. The electronic control unit 56 can also be configured to trigger an alarm 62 indicating that the coolant branch has a coolant leak and that the coolant flow to this branch has been shut off.In other words, the warning message 62 can inform a system user or technician directly, via a sensor signal or error code, or via a remote server (not shown), that a specific coolant branch is at risk and that the coolant flow through that branch has been blocked. In the event that a coolant loss is detected in the cooling system 36, but no coolant leak is identified in the coolant branches 44-1, 44-2, 44-3, the electronic control unit 56 can additionally be configured to interrupt the operation of the liquid pump 42 and trigger an alarm indicating a general coolant loss in the system. In one embodiment (shown in Fig. 2), the electronic control unit 56 can be configured to check each of the multiple coolant branches 44-1, 44-2, 44-3 for a coolant leak by detecting the loss of coolant pressure in each corresponding coolant branch. In particular, the coolant pressure in each coolant branch 44-1, 44-2, 44-3 upstream of the corresponding battery module 30-1, 30-2, 30-3 can be detected using a respective first coolant pressure sensor 64-1, 64-2 or 64-3 (in communication with the electronic control unit 56). Additionally, the coolant pressure in each coolant branch 44-1, 44-2, 44-3 downstream of the corresponding battery module 30-1, 30-2, 30-3 can be detected using a respective second coolant pressure sensor 66-1, 66-2 or 66-3 (also in conjunction with the electronic control unit 56).The detection of a coolant pressure loss in a specific coolant branch 44-1, 44-2, 44-3 would then be based on the corresponding difference between the measured coolant pressures upstream and downstream of the specific battery module 30-1, 30-2, 30-3. In particular, the determined pressure difference exceeding a predetermined value 68 would be considered an indication of a coolant leak in the corresponding coolant branch 44-1, 44-2, or 44-3. In another embodiment (also shown in Fig. 2), the electronic control unit 56 can be configured to check each of the multiple coolant branches 44-1, 44-2, 44-3 for a coolant leak using the corresponding check valves 52-1, 52-2, 52-3. In particular, the coolant pressure in each coolant branch 44-1, 44-2, 44-3 upstream of the corresponding battery module 30-1, 30-2, 30-3 can be detected via the respective first coolant pressure sensor 64-1, 64-2, or 64-3. Additionally, in each coolant branch 44-1, 44-2, 44-3, the response of the corresponding check valve 52-1, 52-2, 52-3 to the detected coolant pressure upstream of the respective battery module can be detected. For example, the response of each one-way valve 52-1, 52-2, 52-3 can be a position of the valve, e.g. fully open or closed. If the check valve opens at the prescribed coolant pressure, then, according to the above design, there is no coolant pressure loss and therefore no leak in the relevant coolant branch 44-1, 44-2, or 44-3. If, however, the check valve does not open or opens too little, it is assumed that the corresponding coolant branch has a leak. In another example, the response of each one-way valve 52-1, 52-2, 52-3 can be determined via a corresponding valve displacement sensor 70-1, 70-2, 70-3, which is configured to transmit its measurement to the electronic control unit 56. In such a design, if the displacement of a particular one-way valve 52-1, 52-2, 52-3 under a specified coolant pressure is within a predetermined displacement range 72, it is assumed that there is no leak in the relevant coolant branch 44-1, 44-2, or 44-3.If, on the other hand, the deflection of a specific one-way valve 52-1, 52-2, 52-3 is below the prescribed coolant pressure and outside the specified deflection range 72 (valve opening too small), it is assumed that the corresponding coolant branch may have a leak. The electronic control unit 56 can be programmed using a lookup table 74 (shown in Fig. 2). The lookup table 74 is intended to contain the adjustment of the corresponding check valves 52-1, 52-2, 52-3 relative to the coolant pressure values in a single coolant branch 44-1, 44-2, 44-3 upstream of the respective battery module 30-1, 30-2, 30-3. The flow rate of the coolant 40 in the main coolant circuit 38 can be detected by a main coolant flow sensor 76 (shown in Fig. 3) and transmitted to the electronic control unit 56. Each coolant branch 44-1, 44-2, 44-3 can contain a corresponding coolant flow sensor 78-1, 78-2, 78-3 downstream of the corresponding battery module 30-1, 30-2, 30-3, which is connected to the electronic control unit 56. As shown in Fig. 3, the electronic control unit 56 can be configured to check each of the coolant branches 44-1, 44-2, 44-3 for a coolant leak by determining the amount of coolant flow.A decrease in coolant flow compared to the flow in the main coolant circuit 38 can be determined by the electronic control unit 56 based on the distributed flow through the coolant branches and using the corresponding coolant flow sensors 78-1, 78-2, 78-3 and the main coolant flow sensor 76. In such a configuration, if the coolant flow detected by the coolant flow sensor 78-1, 78-2, 78-3 at the prescribed coolant flow rate is within a predetermined flow range 80, it is assumed that there is no leak in the relevant coolant branch 44-1, 44-2, or 44-3. Conversely, if the coolant flow detected by the coolant flow sensor 78-1, 78-2, 78-3 at the prescribed coolant pressure is outside the predetermined flow range 80, the assessment would be that the corresponding coolant branch might have a leak. A method 100 for detecting and limiting a coolant leak in a multi-cell rechargeable energy storage system, such as the RESS 24, as shown in Fig. 4 and described below with reference to the structure shown in Figs. 1-3. The method is specifically intended for use in a RESS that employs a main coolant loop connected to a fluid pump, e.g., the main coolant loop 38, and a plurality of coolant branches, such as branches 44-1, 44-2, 44-3, arranged in parallel and each configured to receive a portion of the coolant 40 from the main coolant loop. The RESS in question also has at least one flow valve 50 configured to regulate the coolant 40 received from the main coolant loop 38 and distribute it to the multiple coolant branches 44-1, 44-2, 44-3. Method 100 begins in frame 102 with the control of the flow of coolant 40 in the main coolant circuit 38 of the cooling system 36 via the electronic control unit 56. After frame 102, the method proceeds to frame 104. In frame 104, the method comprises monitoring the cooling system 36 via the electronic control unit 56 for an indication of coolant loss. As described above with reference to Figures 2-3, the indication of coolant loss in the cooling system 36 may be a decrease in the coolant volume or level in the reservoir 60. After frame 104, the method proceeds to frame 106. In frame 106, the method comprises checking each of the coolant branches 44-1, 44-2, 44-3 via the electronic control unit 56 for a coolant leak in response to an indication of coolant loss in the cooling system 36. As described above with reference to Figures 2-3, the indication of coolant loss in the cooling system 36 may be a decrease in the coolant volume or level in the reservoir 60.As described in section 2, checking the coolant branches 44-1, 44-2, 44-3 for a coolant leak may include detecting a loss of coolant pressure or flow in each corresponding coolant branch. Following frame 106, the method transitions to frame 108. In frame 108, the method comprises the identification of a coolant branch with a coolant leak via the electronic control unit 56 among branches 44-1, 44-2, 44-3. For example, the coolant pressure in a single coolant branch 44-1, 44-2, or 44-3 upstream of the respective battery module 30-1, 30-2, 30-3 can be detected via a corresponding first coolant pressure sensor 64-1, 64-2, 64-3. The coolant pressure can also be detected in the same coolant branch 44-1, 44-2, 44-3 downstream of the corresponding battery module 30-1, 30-2, 30-3 via a corresponding second coolant pressure sensor 66-1, 66-2, 66-3. As described in Fig. 2, the difference between the upstream and downstream coolant pressure can then be used to identify the coolant branch containing the leak. Alternatively, the coolant pressure in the coolant branches 44-1, 44-2, or 44-3 upstream of the battery modules 30-1, 30-2, 30-3 can be detected via the first coolant pressure sensors 64-1, 64-2, 64-3, and the response of the one-way valves 52-1, 52-2, 52-3 to the upstream coolant pressure can be detected. The detected response of the one-way valves 52-1, 52-2, 52-3 can be the valve's position or its measured deflection, for example, via the corresponding valve deflection sensors 70-1, 70-2, 70-3. Alternatively, the assessment of a coolant leak in the coolant branches 44-1, 44-2, 44-3 can be carried out by determining the amount of coolant flow through the respective branches via the corresponding coolant flow sensors 78-1, 78-2, 78-3 and comparing it with the coolant flow through the main coolant circuit 38, which is detected by the main coolant flow sensor 76. Following frame 108, the procedure proceeds to frame 110. In frame 110, the procedure comprises shutting off the flow of coolant 40 into the coolant branch 44-1, 44-2, or 44-3 identified as being affected by the coolant leak, via the flow valve(s) 50 regulated by the electronic control unit 56. Following frame 110, the procedure may proceed to frame 112. In frame 112, after shutting off the coolant flow into the coolant branch affected by the leak, the procedure comprises setting the warning message 62 via the electronic control unit 56, signaling the detected presence of the coolant leak. The warning message 62 may indicate the affected coolant branch and / or the fact that the coolant flow has been interrupted.Such a warning can be stored in the memory of the electronic control unit 56 so that it can later be retrieved by a technician and / or transmitted to a remote server. After frame 110 or frame 112, the procedure can return to frame 104 to continue monitoring the coolant condition in cooling system 36. However, if no leak is detected in coolant branches 44-1, 44-2, 44-3, the procedure can repeat the evaluation of the coolant branches in frame 106 or trigger an alarm indicating a general coolant loss in system 36. Otherwise, the procedure can be completed in frame 114 when the electrical load on the RESS 24 has been removed, for example, when the vehicle 10 has come to a standstill, power sources 14 and 20 have been switched off, and the liquid pump 42 has been deactivated. 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 modes and other embodiments for carrying out the claimed description have been described in detail, there are various alternative designs and embodiments for carrying out the disclosure defined in the appended claims. Furthermore, the embodiments shown in the drawings or the features of different 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 exemplary embodiments can be combined with one or more other desired features of other embodiments, leading to other embodiments that are not described in words or by reference to the figures. Accordingly, such other embodiments fall within the scope and application of the appended claims.
Claims
A system for detecting and limiting coolant leaks for a multi-cell rechargeable energy storage system (24), RESS, with a plurality of battery cells (28) arranged in individual battery modules (30-1, 30-2, 30-3), wherein the system (36) for detecting and limiting coolant leaks comprises: a cooling system (36) including: a main coolant circuit (38) designed for circulating the coolant; several coolant branches (44-1, 44-2, 44-3) arranged in parallel, each coolant branch (44-1, 44-2, 44-3) being configured to take a portion of the coolant from the main coolant circuit (38) to adjust the temperature of one of the respective battery modules (30-1, 30-2, 30-3); and at least one flow valve (50) configured to regulate the coolant circulating through the main coolant circuit (38) and to the majority of coolant branches (44-1, 44-2,44-3); and an electronic control unit (56) that is operationally connected to the cooling system (36) and is configured to: monitor the cooling system (36) for indications of coolant loss; check each of the multiple coolant branches (44-1, 44-2, 44-3) for a coolant leak in response to the indication of coolant loss; identify one coolant branch (44-1, 44-2, 44-3) from the plurality of coolant branches (44-1, 44-2, 44-3) that has a coolant leak; and blocking the flow of coolant into the coolant branch (44-1, 44-2, 44-3) with the coolant leak via the at least one flow valve (50), wherein the electronic control unit (56) is additionally configured to trigger an alarm indicating that the coolant branch (44-1, 44-2, 44-3) has a coolant leak and the flow of coolant has been shut off, wherein the main coolant circuit (38) includes a reservoir (60),which is configured for the supply of coolant and has a coolant level sensor (60A) which is connected to the electronic control unit (56), and wherein the indication of a coolant loss in the coolant system (36) is a decrease in the coolant in the reservoir, wherein the electronic control unit (56) is configured to examine each of the multiple coolant branches (44-1, 44-2, 44-3) for a coolant leak by detecting the loss of coolant pressure in each corresponding coolant branch (44-1, 44-2, 44-3), wherein the detection of coolant pressure loss in each coolant branch (44-1, 44-2, 44-3) is achieved by: detecting the coolant pressure in a single coolant branch (44-1, 44-2, 44-3) upstream of the respective battery module (30-1, 30-2, 30-3); and determining the coolant pressure in the relevant coolant branch (44-1, 44-2, 44-3) downstream of the relevant battery module (30-1, 30-2, 30-3),wherein each coolant branch (44-1, 44-2, 44-3) contains a one-way valve (52-1, 52-2, 52-3) configured to control the coolant flow from the coolant branch (44-1, 44-2, 44-3) and is connected to the electronic control unit (56), and wherein the detection of a coolant pressure loss in each coolant branch (44-1, 44-2, 44-3) is carried out by: sensing the coolant pressure in a single coolant branch (44-1, 44-2, 44-3) upstream of the respective battery module (30-1, 30-2, 30-3); and determining the response of a corresponding check valve (52-1, 52-2, 52-3) to the determined coolant pressure upstream of the relevant battery module (30-1, 30-2, 30-3), wherein each coolant branch (44-1, 44-2, 44-3) includes a valve displacement sensor (70-1, 70-2, 70-3) that communicates with the electronic control unit (56), and wherein the response of each one-way valve (52-1, 52-2, 52-3) is determined via the valve displacement sensor (70-1, 70-2,70-3), wherein the electronic control unit (56) is programmed with a lookup table (74) for the displacement of the corresponding one-way valve (52-1, 52-2, 52-3) depending on the coolant pressure in a single coolant branch (44-1, 44-2, 44-3) upstream of the respective battery module (30-1, 30-2, 30-3). System for detecting and limiting coolant leaks according to claim 1, wherein each coolant branch (44-1, 44-2, 44-3) comprises a coolant flow sensor (78-1, 78-2, 78-3) downstream of the corresponding battery module (30-1, 30-2, 30-3) and in conjunction with the electronic control unit (56), and wherein the electronic control unit (56) is configured to check each of the multiple coolant branches (44-1, 44-2, 44-3) for a coolant leak by determining the amount of coolant flowing through them using the corresponding coolant flow sensor (78-1, 78-2, 78-3). System for detecting and limiting coolant leaks according to claim 1, wherein the at least one flow valve (50) is one of the following: a multi-way valve arrangement located in a connection between the main coolant circuit (38) and the plurality of coolant branches (44-1, 44-2, 44-3) and configured to control a flow of coolant into each of the coolant branches (44-1, 44-2, 44-3); or a plurality of throttle valves (50-1, 50-2, 50-3), wherein each throttle valve is 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 is configured to control a flow of coolant into the coolant branch (44-1, 44-2, 44-3) in question.