Patent Publication Number: US-2022219555-A1

Title: Liquid-cooled charging equipment with multiple charging connector assemblies and method of operating the same

Description:
BACKGROUND 
     Technical Field 
     The present disclosure relates to a charging equipment and a method of operating the same, and more particularly to a liquid-cooled charging equipment with multiple charging connector assemblies applied to electric vehicles and a method of operating the same. 
     Description of Related Art 
     The statements in this section merely provide background information related to the present disclosure and do not necessarily constitute prior art. 
     With the development of the electric vehicle (EV) industry, modern EVs are usually loaded with large-capacity rechargeable batteries in order to increase the travel distance after being charged. In response to this technological development trend, fast EV charging equipment is generally designed to provide a relatively large output power (for example, 50 kW to 350 kW) to quickly charge EVs to avoid long waiting time of charging for car owners. However, the larger output power may cause the charging cable to generate high heat due to the larger current during the charging process. Therefore, the fast EV charging equipment is usually equipped with a cooling device (for example, in a liquid-cooling manner) to dissipate the heat of the charging connector of the charging connector assembly through the cooling pipeline design. 
     For existing liquid-cooled high-power charging equipment with multiple charging connector assemblies, although it has a multiple charging connector assemblies design, all charging connector assemblies are usually designed to be connected to a common coolant supply pipe used to supply coolant. Therefore, as long as one of the charging connector assemblies is abnormal, the remaining charging connector assemblies will not be able to continue to operate due to the absence of the coolant supply when the system performs a protective action to close the valve of the aforementioned coolant supply pipes. As a result, the availability and reliability of traditional liquid-cooled high-power charging equipment with multiple charging connector assemblies are relatively poor. 
     Accordingly, the liquid-cooled charging equipment with multiple charging connector assemblies of the present disclosure is provided to determine whether the pipe has abnormal coolant leakage or whether the charging connector has abnormal overheating by using the pressure sensor, the flow sensor, and the temperature sensor, so that the relevant actions such as early warning, protection, and maintenance can be taken in time to increase the service life of charging connector assemblies and electric vehicles and ensure user safety. In addition, once one or some of the charging connector assemblies are disabled due to abnormal conditions, the rest normal charging connector assemblies can still continue to operate, which increases the availability and reliability of the liquid-cooled charging equipment. 
     SUMMARY 
     An object of the present disclosure is to provide a liquid-cooled charging equipment with multiple charging connector assemblies to solve the problems of the existing technology. 
     In order to achieve the above-mentioned object, the liquid-cooled charging equipment with multiple charging connector assemblies includes a recirculating cooling apparatus, a plurality of charging connector assemblies, a plurality of coolant supply pipes, a plurality of coolant return pipes, a plurality of valves, and a control unit. The recirculating cooling apparatus supplies a coolant, and has an outlet side and an inlet side. Each charging connector assembly includes a charging connector and a charging cable connected to the charging connector, and has an inlet end and an outlet end. A first end of each coolant supply pipe is connected to the outlet side, and a second end of each coolant supply pipe is correspondingly connected to the inlet end of each charging cable. A first end of each coolant return pipe is correspondingly connected to the outlet end of each charging cable, and a second end of each coolant return pipe is connected to the inlet side. Each valve is correspondingly disposed in each coolant supply pipe. The control unit is coupled to the valves and the charging connector assemblies. When at least one of the charging connector assemblies is in operation of charging, the control unit opens the valve corresponding to the charging connector assembly in operation. 
     Accordingly, the liquid-cooled charging equipment with multiple charging connector assemblies is provided to determine whether the pipe has abnormal coolant leakage or whether the charging connector has abnormal overheating by using the pressure sensor, the flow sensor, and the temperature sensor, so that the relevant actions such as early warning, protection, and maintenance can be taken in time to increase the service life of charging connector assemblies and electric vehicles and ensure user safety. In addition, once one or some of the charging connector assemblies are disabled due to abnormal conditions, the rest normal charging connector assemblies can still continue to operate, which increases the availability and reliability of the liquid-cooled charging equipment. 
     Another object of the present disclosure is to provide a method of operating a liquid-cooled charging equipment with multiple charging connector assemblies to solve the problems of the existing technology. 
     In order to achieve the above-mentioned object, the method of operating the liquid-cooled charging equipment with multiple charging connector assemblies includes steps of: opening, when at least one of the charging connector assemblies is in operation of charging, the valve corresponding to the charging connector assembly; measuring a first pressure value, a first temperature value, and a flow rate value of the coolant supply pipe connected by the charging connector assembly through which the coolant flows; measuring a second pressure value and a second temperature of the coolant return pipe connected by the charging connector assembly through which the coolant flows; determining if the coolant supply pipe is abnormal according to the first pressure value, the second pressure value, the first temperature value, and/or the flow rate value, and closing the valve corresponding to the coolant supply pipe that is determined to be abnormal; and determining if the coolant return pipe is abnormal according to the first temperature value and/or the second temperature value, and closing the valve corresponding to the coolant return pipe that is determined to be abnormal. 
     Accordingly, the method of operating the liquid-cooled charging equipment with multiple charging connector assemblies is provided to determine whether the pipe has abnormal coolant leakage or whether the charging connector as abnormal overheat by using the pressure sensor, the flow sensor, and the temperature sensor so that the relevant actions such as early warning, protection, and maintenance can be taken in time to increase the service life of charging connector assemblies and electric vehicles and ensure user safety. In addition, once one or some of the charging connector assemblies are disabled due to abnormal conditions, the rest normal charging connector assemblies can still continue to operate, which increases the availability and reliability of the liquid-cooled charging equipment. 
     Further another object of the present disclosure is to provide a method of operating a liquid-cooled charging equipment with multiple charging connector assemblies to solve the problems of the existing technology. 
     In order to achieve the above-mentioned object, the method of operating the liquid-cooled charging equipment with multiple charging connector assemblies includes steps of: turning on the valve corresponding to the charging connector when at least one of the charging connector assemblies charges, measuring a temperature value of the charging connector, and determining that the charging connector is abnormal according to the temperature value, and turning off the valve corresponding to the abnormal charging connector. 
     Accordingly, the method of operating the liquid-cooled charging equipment with multiple charging connector assemblies is provided to determine whether the pipe is in the coolant leakage or whether the charging connector is in the overheat by using the pressure sensor, the flow sensor, and the temperature sensor so that the early warning, protection, and maintenance can be taken in time to increase the service life of charging connector assemblies and electric vehicles and ensure the safety of users. In addition, once one or some of the charging connector assemblies are disabled due to abnormal conditions, other normal charging connector assemblies can still continue to operate to increase the availability and reliability of the liquid-cooled charging equipment. 
     It is to be understood that both the foregoing general description and the following detailed description are exemplary, and are intended to provide further explanation of the present disclosure as claimed. Other advantages and features of the present disclosure will be apparent from the following description, drawings, and claims. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
       The present disclosure can be more fully understood by reading the following detailed description of the embodiment, with reference made to the accompanying drawing as follows: 
         FIG. 1  is a schematic system diagram of a liquid-cooled charging equipment with multiple charging connector assemblies according to the present disclosure. 
         FIG. 2  is a schematic diagram of the liquid-cooled charging equipment with multiple charging connector assemblies operating in a normal condition according to a first embodiment of the present disclosure. 
         FIG. 3  is a schematic diagram of the liquid-cooled charging equipment with multiple charging connector assemblies operating in a normal condition according to a second embodiment of the present disclosure. 
         FIG. 4  is a schematic diagram of the liquid-cooled charging equipment with multiple charging connector assemblies operating in an abnormal condition according to a first embodiment of the present disclosure. 
         FIG. 5  is a schematic diagram of the liquid-cooled charging equipment with multiple charging connector assemblies operating in an abnormal condition according to a second embodiment of the present disclosure. 
         FIG. 6  is a flowchart of a method of operating the liquid-cooled charging equipment with multiple charging connector assemblies according to the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference will now be made to the drawing figures to describe the present disclosure in detail. It will be understood that the drawing figures and exemplified embodiments of present disclosure are not limited to the details thereof. 
     Please refer to  FIG. 1 , which shows a schematic system diagram of a liquid-cooled charging equipment with multiple charging connector assemblies according to the present disclosure. The liquid-cooled charging equipment with multiple charging connector assemblies includes a recirculating cooling apparatus  10 , a plurality of charging connector assemblies  20 , a plurality of coolant supply pipes  30 , a plurality of coolant return pipes  40 , a plurality of valves  50 , and a control unit  100 . Although the number of the plural charging connector assemblies  20  shown in  FIG. 1  is two, in actual applications, it is not limited to two charging connector assemblies  20 , for example, more than three charging connector assembly  20  may be used for charging at the same time. For explanation convenience, two charging connector assemblies  20  are taken as an example for description. Furthermore, the term “plural” mentioned above not only means that the number of such devices and components is multiple, but also means that the number is correspondingly equal. For example, if the number of the plurality of charging connector assemblies  20  is three, it means that the number of the plurality of coolant supply pipes  30 , the plurality of coolant return pipes  40 , and the plurality of valves  50  are all three, corresponding to each other. 
     As shown in  FIG. 1 , the recirculating cooling apparatus  10  has an outlet side  11  and an inlet side  12 . The recirculating cooling apparatus  10  mainly includes a heat exchanger  13 , a heat-dissipating fan  14 , a liquid-storing tank  15 , and a pump  16 . The heat exchanger  13  cooperates with the heat-dissipating fan  14 , and is connected to an output side of the coolant return pipe  40  for cooling the higher-temperature coolant flowing from the coolant return pipe  40  back to the recirculating cooling apparatus  10 , and the cooled lower-temperature coolant flows back to the liquid-storing tank  15  for storage. The pump  16  is connected to an input side of the coolant supply pipe  30  for drawing and transporting the coolant during the circulating operation so that the lower-temperature coolant is sent to the coolant supply pipes  30  to cool the charging connector assemblies  20 . In this embodiment, the coolant may be, for example but not limited to, the solution with conductivity of pure water plus ethylene glycol or the solution with conductivity of pure water plus propylene glycol, or it may be, for example but not limited to, oil without conductivity. 
     As shown in  FIG. 1 , the charging connector assemblies  20  includes a first charging connector assembly  20 A and a second charging connector assembly  20 B. The first charging connector assembly  20 A has a charging connector  21 A, and a charging cable  22 A that is connected to the charging connector  21 A and has an inlet end  23 A and an outlet end  24 A. Similarly, the second charging connector assembly  20 B has a charging connector  21 B, and a charging cable  22 B that is connected to the charging connector  21 B and has an inlet end  23 B and an outlet end  24 B. For the first charging connector assembly  20 A, the inlet end  23 A is an end where the coolant flows into the first charging connector assembly  20 A, and the outlet end  24 A is an end where the coolant flows out from the first charging connector assembly  20 A. Therefore, the coolant flows into the first charging connector assembly  20 A through the inlet end  23 A and flows out from the first charging connector assembly  20 A through the outlet end  24 A to cool the charging connector  21 A. The second charging connector assembly  20 B has the same structure, so the detail is omitted here for conciseness. 
     A first end  31 A of a first coolant supply pipe  30 A corresponding to the first charging connector assembly  20 A is connected to the outlet side  11  of the recirculating cooling apparatus  10 , and a second end  32 A of the first coolant supply pipe  30 A is connected to the inlet end  23 A of the first charging connector assembly  20 A. The second coolant supply pipe  30 B has the same structure, so the detail is omitted here for conciseness. In other words, as shown in  FIG. 1 , the first end  31 A of the first coolant supply pipe  30 A is connected with a first end  31 B of a second coolant supply pipe  30 B, and the first ends  31 A and  31 B are commonly connected to the outlet side  11  of the recirculating cooling apparatus  10 . Further, the second end  32 A of the first coolant supply pipe  30 A is correspondingly connected to the inlet end  23 A of the first charging connector assembly  20 A, and a second end  32 B of the second coolant supply pipe  30 B is correspondingly connected to the inlet end  23 B of the second charging connector assembly  20 B. 
     A first end  41 A of a first coolant return pipe  40 A corresponding to the first charging connector assembly  20 A is connected to the outlet end  24 A of the first charging connector assembly  20 A, and a second end  42 A of the first coolant return pipe  40 A is connected to the inlet side  12 . The second coolant return pipe  40 B has the same structure, so the detail is omitted here for conciseness. In other words, as shown in  FIG. 1 , the first end  41 A of the first coolant return pipe  40 A is correspondingly connected to the outlet end  24 A of the first charging connector assembly  20 A, and a first end  41 B of the second coolant return pipe  40 B is correspondingly connected to the outlet end  24 B of the second charging connector assembly  20 B. Further, the second end  42 A of the first coolant return pipe  40 A is connected with a second end  42 B of a second coolant return pipe  40 B, and the second ends  42 A and  42 B are commonly connected to the inlet side  12  of the recirculating cooling apparatus  10 . 
     A plurality of valves  50  are correspondingly disposed in the coolant supply pipes  30 , respectively. Specifically, the first coolant supply pipe  30 A has a first valve  50 A and the second coolant supply pipe  30 B has a second valve  50 B, and the first valve  50 A and the second valve  50 B are controlled to open or close so as to control whether the coolant flows through the first coolant supply pipe  30 A and/or the second coolant supply pipe  30 B. For example, assuming that there are three charging connector assemblies  20 , including a first charging connector assembly  20 A, a second charging connector assembly  20 B, and a third charging connector assembly  20 C, therefore there are three corresponding coolant supply pipes  30 , including a first coolant supply pipe  30 A, a second coolant supply pipe  30 B, and a third coolant supply pipe  30 C. Each of the three coolant supply pipes  30  has one valve  50 , including a first valve  50 A, a second valve  50 B, and a third valve  50 C. In another embodiment, the liquid-cooled charging equipment includes a switching unit. The switching unit is coupled to the control unit  100  and the valves  50 , and the switching unit receives a valve control command provided from the control unit  100  to correspondingly control the valves to open on or close. 
     Therefore, when any one of the charging connector assemblies  20  is in operation of charging EV, the corresponding valve  50  is controlled so that the lower-temperature coolant from the outlet side  11  of the recirculating cooling apparatus  10  flows to the corresponding coolant supply pipe  30  to cool the corresponding charging connector assembly  20 . For example, when the first charging connector assembly  20 A, the second charging connector assembly  20 B, and the third charging connector assembly  20 C are in operation of charging and need to be cooled, the first valve  50 A, the second valve  50 B, and the third valve  50 C may be opened so that the coolant from the recirculating cooling apparatus  10  flows to the first charging connector assembly  20 A, the second charging connector assembly  20 B, and the third charging connector assembly  20 C through the first coolant supply pipe  30 A, the second coolant supply pipe  30 B, and the third coolant supply pipe  30 C, respectively. When only the third charging connector assembly  20 C needs to be cooled, the first valve  50 A and the second valve  50 B may be closed and the third valve  50 C may be opened so that the coolant from the recirculating cooling apparatus  10  may only flow to the third charging connector assembly  20 C through the third coolant supply pipe  30 C, but does not flow to the first charging connector assembly  20 A and the second charging connector assembly  20 B through the first coolant supply pipe  30 A and the second coolant supply pipe  30 B, respectively. In particular, when the charging equipment operates, not all charging connector assemblies will be in operation at the same time, that is, only one charging connector assembly  20 A is in operation or only two charging connector assemblies  20 A,  20 C are in operation. In this condition, the control unit  100  only needs to open the corresponding valve(s) for the charging connector assembly(s) that is (are) in operation and need(s) to be cooled. In particular, the valves  50  may be, but not limited to, arranged and integrated into one modular, or be separated into three different modules. As long as these valves  50  can achieve the function of controlling the flow of the coolant through the coolant supply pipes  30  or blocking the flow of the coolant through the coolant supply pipes  30 , they should be included in the scope of the present disclosure. 
     In addition, the liquid-cooled charging equipment further includes a plurality of unidirectional valves  60 . The plurality of unidirectional valves  60  are correspondingly disposed in the coolant return pipe  40 , respectively, that is, the first coolant return pipe  40 A has a first unidirectional valve  60 A, the second coolant return pipe  40 B has a second unidirectional valve  60 B, and the third coolant return pipe  40 C has a third unidirectional valve  60 C. The unidirectional valve  60  is used to limit the flow direction of the coolant, so that the coolant can only flow from the second end  42  of the coolant return pipe  40  to the inlet side  12  of the recirculating cooling apparatus  10 , preventing the coolant from flowing from the common connection point of the coolant return pipes  40  back to other charging connector assemblies, which may lead to abnormal heat dissipation. In one embodiment, the unidirectional valve  60  may be a check valve or similar components or devices that can achieve unidirectional (one-way) flow of the coolant. 
     For example, as mentioned above, when only the third charging connector assembly  20 C needs to be cooled, the third valve  50 C is opened so that the coolant from the recirculating cooling apparatus  10  may only flow to the third charging connector assembly  20 C through the third coolant supply pipe  30 C, without flowing to the first charging connector assembly  20 A and the second charging connector assembly  20 B through the first coolant supply pipe  30 A and the second coolant supply pipe  30 B, respectively. In addition, with the implementation of the unidirectional valves  60 , the coolant flowing through the third charging connector assembly  20 C flows through the third unidirectional valve  60 C to the inlet side  12  of the recirculating cooling apparatus  10  via the second end of the third coolant return pipe  40 C. Since the second end of the first coolant return pipe  40 A, the second end of the second coolant return pipe  40 B, and the second end of the third coolant return pipe  40 C are connected together and commonly connected to the inlet side  12  of the recirculating cooling apparatus  10 , without the unidirectional valves  60 , even if there is no coolant flowing to the first charging connector assembly  20 A and the second charging connector assembly  20 B through the first coolant supply pipe  30 A and the second coolant supply pipe  30 B, the coolant flowing out from the third coolant return pipe  40 C may still flow back to the first charging connector assembly  20 A and the second charging connector assembly  20 B through the first coolant return pipe  40 A and the second coolant return pipe  40 B. Therefore, the implementation of the first unidirectional valve  60 A and the second unidirectional valve  60 B may prevent the coolant from flowing back to the first charging connector assembly  20 A and the second charging connector assembly  20 B. 
     In one embodiment, the liquid-cooled charging equipment further includes a plurality of first pressure sensors  71  and a plurality of second pressure sensors  72 . The plurality of first pressure sensors  71  are correspondingly disposed in the coolant supply pipes  30  respectively for measuring a first pressure value of the coolant supply pipe  30 . The plurality of second pressure sensors  72  are correspondingly disposed in the coolant return pipes  40  respectively for measuring a second pressure value of the coolant return pipe  40 . For example, assuming that there are three coolant supply pipes  30 , there will be three first pressure sensors  71  ( 71 A,  71 B,  71 C), which are respectively disposed in the first coolant supply pipe  30 A, the second coolant supply pipe  30 B, and the third coolant supply pipe  30 C for measuring the first pressure value of each of the three coolant supply pipes  30 . Similarly, assuming that there are three coolant return pipes  40 , there will also be three second pressure sensors  72  ( 72 A,  72 B,  72 C), which are respectively disposed in the first coolant return pipe  40 A, the second coolant return pipe  40 B, and the third coolant return pipe  40 C for measuring the second pressure value of each of the three coolant return pipes  40 . 
     In another embodiment, the liquid-cooled charging equipment further includes a plurality of first temperature sensors  81  and a plurality of second temperature sensors  82 . The plurality of first temperature sensors  81  are correspondingly disposed in the coolant supply pipes  30  respectively for measuring a first temperature value of the coolant supply pipe  30 . The plurality of second temperature sensors  82  are correspondingly disposed in the coolant return pipes  40  respectively for measuring a second temperature value of the coolant return pipe  40 . For example, assuming that there are three coolant supply pipes  30 , there will also be three first temperature sensors  81  ( 81 A,  81 B,  81 C), which are respectively disposed in the first coolant supply pipe  30 A, the second coolant supply pipe  30 B, and the third coolant supply pipe  30 C for measuring the first temperature value of each of the three coolant supply pipes  30 . Similarly, assuming that there are three coolant return pipes  40 , there will also be three second temperature sensors  82  ( 82 A,  82 B,  82 C), which are respectively disposed in the first coolant return pipe  40 A, the second coolant return pipe  40 B, and the third coolant return pipe  40 C for measuring the second temperature value of each of the three coolant return pipes  40 . 
     In another embodiment, the liquid-cooled charging equipment further includes a plurality of third temperature sensors  83 . The plurality of third temperature sensors  83  are correspondingly disposed in the charging connectors  21  respectively for measuring a third temperature value of the charging connector  21 . In one embodiment, the third temperature sensor  83  may be a negative temperature coefficient resistor (NTC resistor), also referred to as “NTC thermistor”. Therefore, with the thermal characteristic of the NTC that its resistance decreases as the temperature of the charging connector  21  increases, or its resistance increases as the temperature of the charging connector  21  decreases, the temperature change of the charging connector  21  can be detected. 
     In another embodiment, the liquid-cooled charging equipment further includes a plurality of flow sensors  90 . The plurality of flow sensors  90  are correspondingly disposed in the coolant supply pipes  30  respectively for measuring a flow rate value of the coolant supply pipe  30 . For example, assuming there are three coolant supply pipes  30 , there will also be three flow sensors  90  ( 90 A,  90 B,  90 C), which are respectively disposed in the first coolant supply pipe  30 A, the second coolant supply pipe  30 B, and the third coolant supply pipe  30 C for measuring the flow rate value of each of three coolant supply pipes  30 . 
     In the following, different operation scenarios will be explained with different diagrams. The liquid-cooled charging equipment with multiple charging connector assemblies of the present disclosure further includes a controller or a control unit. The controller or the control unit handles the functions such as comparison, processing or calculation of the data measured by the aforementioned sensors, as well as the communication with the controller of the electric vehicle. 
     Please refer to  FIG. 2 , which shows a schematic diagram of the liquid-cooled charging equipment with multiple charging connector assemblies operating in a normal condition according to a first embodiment of the present disclosure. After the charging connector assembly of the liquid-cooled charging equipment is connected to the electric vehicle, the controller of the electric vehicle and the charging equipment communicate with each other through handshaking and have an agreement (coordination) between the charging demand and the power supply capacity of the charging equipment, and then the charging connector assembly is permitted to charge the electric vehicle. In this embodiment, the first charging connector assembly  20 A and the second charging connector assembly  20 B can normally provide electricity for the charging operation. Therefore, the first valve  50 A of the first coolant supply pipe  30 A and the second valve  50 B of the second coolant supply pipe  30 B are opened, so that the coolant from the recirculating cooling apparatus  10  is able to flow to the first charging connector  21 A of the first charging connector assembly  20 A through the first coolant supply pipe  30 A, and to the second charging connector  21 B of the second charging connector assembly  20 B through the second coolant supply pipe  30 B to cool the first charging connector  21 A and the second charging connector  21 B. 
     Take the first charging connector assembly  20 A as an example. If the first pressure value of the first coolant supply pipe  30 A measured by the first pressure sensor  71 A and the second pressure value of the first coolant return pipe  40 A measured by the second pressure sensor  72 A are normal, the first temperature value of the first coolant supply pipe  30 A measured by the first temperature sensor  81 A and the second temperature value of the first coolant return pipe  40 A measured by the second temperature sensor  82 A are normal, the third temperature value of the first charging connector  21 A measured by the third temperature sensor  83 A is normal, and the flow rate value of the first coolant supply pipe  30 A measured by the flow sensor  90 A is normal, it can be determined that the cooling operation of the first charging connector assembly  20 A is normal. Similarly, it is the same for the second charging connector assembly  20 B. Therefore, the cooling operations of the first charging connector assembly  20 A and the second charging connector assembly  20 B shown in  FIG. 2  are normal. 
     In particular, whether the pressure of the coolant supply pipe  30  and the coolant return pipe  40  are normal or not can be determined according to the first pressure value of the coolant supply pipe  30  and the second pressure value of the coolant return pipe  40  individually. That is, as long as one of the pressure values is greater than a predetermined pressure upper limit or less than a predetermined pressure lower limit, it can be determined that the pressure of the pipe is (abnormal) too high or too low. Or, it can be determined that the pressure of at least one of the coolant supply pipe  30  and the coolant return pipe  40  is too high or too low according to the difference between the first pressure value and the second pressure value being greater than a predetermined pressure difference limit. 
     Similarly, whether the temperature of the coolant supply pipe  30  and the coolant return pipe  40  are normal or not can be determined according to the first temperature value (lower-temperature) of the coolant supply pipe  30  and the second pressure value (higher-temperature) of the coolant return pipe  40  individually. For example, the first temperature value and the second temperature value can be compared with different predetermined temperature limits to determine whether the temperature of the coolant supply pipe  30  and/or the temperature of the coolant return pipe  40  is/are too high or not. Alternatively, it can be determined that the temperature of at least one of the coolant supply pipe  30  and the coolant return pipe  40  is too high according to a temperature difference between the first temperature value and the second temperature value being greater than a predetermined temperature difference limit. 
     Similarly, whether the temperature of the charging connector is normal or not may be determined according to the third temperature value. For example, when the third temperature value is greater than a temperature limit, it may be determined that the temperature of the charging connector is too high. In practical applications, different relevant actions such as early warning and protection mechanisms can also be performed according to the over-temperature condition. For example, when the third temperature value, namely a temperature of the body of the charging connector, is higher than a first temperature limit, for example 70 degrees Celsius, not yet reaching the temperature required to disable the charging operation of the charging connector assembly, for example 85 degrees Celsius, the controller or the control unit may only send out early warning signals as a notification and reference to the backend monitoring operators, so that the operators can continuously pay attention to this early warning and take preventive actions if necessary. When the third temperature value is higher than a second temperature limit, for example 85 degrees Celsius, the controller or the control unit disables the charging operation of the charging connector assembly to increase the service life of the charging connector assembly and the electric vehicle and ensure the user safety. 
     Similarly, whether the flow rate of the flow sensor  90  is normal or not can be determined according to the flow rate value. For example, when the flow rate value is greater than a flow rate upper limit or less than a flow rate lower limit, it may be determined that the flow rate of the coolant supply pipe  30  is too high or too low. 
     Please refer to  FIG. 3 , which shows a schematic diagram of the liquid-cooled charging equipment with multiple charging connector assemblies operating in a normal condition according to a second embodiment of the present disclosure. In this embodiment, one of the two charging connectors (for example the first charging connector) is in a charging operation and the other charging connector (for example the second charging connector) is in an idle state. Since the first charging connector is normal in the charging operation, the first valve  50 A corresponding to the first charging connector assembly  20 A is opened. Therefore, the coolant from the recirculating cooling apparatus  10  flows to the first charging connector assembly  20 A through the first coolant supply pipe  30 A to cool the first charging connector assembly  20 A. Also, the higher-temperature coolant that flows back to the recirculating cooling apparatus  10  through the first coolant return pipe  40 A is cooled by the heat exchanger  13  cooperating with the heat-dissipating fan  14  for recycle and reuse purposes. In addition, since the second charging connector assembly  20 B is in the idle state, the second valve  50 B corresponding to the second charging connector assembly  20 B is closed. Therefore, the coolant does not flow through the second coolant supply pipe  30 B and does not cool the second charging connector assembly  20 B. As mentioned above, with the implementation of the unidirectional valve  60 , it is possible to prevent the coolant from flowing back to the second charging connector assembly  20 B. 
     Please refer to  FIG. 4 , which shows a schematic diagram of the liquid-cooled charging equipment with multiple charging connector assemblies operating in an abnormal condition according to a first embodiment of the present disclosure. In this embodiment, a pipe, such as the first coolant supply pipe  30 A corresponding to one of the two charging connectors (for example the first charging connector) is in an abnormal condition of coolant leakage. In this abnormal condition, since the first pressure value measured by the first pressure sensor  71 A of the first coolant supply pipe  30 A is lower than a pressure lower limit, it can be determined that the abnormal condition of coolant leakage of the first coolant supply pipe  30 A occurs. Alternatively, when the flow rate value measured by the flow sensor  90 A of the first coolant supply pipe  30 A is lower than a flow rate lower limit, it can be also determined that the abnormal condition of coolant leakage of the first coolant supply pipe  30 A occurs. In addition, if the abnormal condition of coolant leakage of the first coolant supply pipe  40 A occurs, the second pressure value measured by the second pressure sensor  72 A can also be used to determine the abnormal condition, so the detail is omitted here for conciseness. 
     Please refer to  FIG. 5 , which shows a schematic diagram of the liquid-cooled charging equipment with multiple charging connector assemblies operating in an abnormal condition according to a second embodiment of the present disclosure. In this embodiment, one of the two charging connectors (for example the first charging connector) is in an abnormal condition of overheat. In this abnormal condition, since the third temperature value measured by the third temperature sensor  83 A of the first charging connector assembly  20 A is higher than a temperature upper limit, it can be determined that the abnormal condition of overheat of the first charging connector  21 A occurs. Alternatively, when a temperature difference between the first temperature value measured by the first temperature sensor  81 A of the first coolant supply pipe  30 A and the second temperature value measured by the second temperature sensor  82 A of the first coolant return pipe  40 A is higher than a temperature difference limit, it can be determined that the abnormal condition of overheat of the first charging connector  21 A occurs. 
     Please refer to  FIG. 6 , which shows a flowchart of a method of operating the liquid-cooled charging equipment with multiple charging connector assemblies according to the present disclosure. The method of operating the liquid-cooled charging equipment with multiple charging connector assemblies includes the following steps as follows. Opening the valve corresponding to the charging connector assembly when at least one of the charging connector assemblies is in operation of charging so that the charging connector of the charging connector assembly is cooled by the lower-temperature coolant (S 11 ). Measuring the first pressure value, the first temperature value, and the flow rate value of the coolant supply pipe connected by the charging connector assembly through which the coolant flows (S 12 ). Measuring the second pressure value and the second temperature of the coolant return pipe connected by the charging connector assembly through which the coolant flows (S 13 ). Measuring the third temperature value of the charging connector (S 14 ). Determining if the coolant supply pipe is abnormal (for example, the abnormal condition of coolant leakage) according to the first pressure value, the second pressure value, the first temperature value, and/or the flow rate value, and closing the valve corresponding to the abnormal coolant supply pipe (S 15 ). Determining if the coolant return pipe is abnormal (for example, the abnormal condition of overheat) according to the first temperature value and/or the second temperature value, and closing the valve corresponding to the abnormal coolant return pipe (S 16 ). Determining if the charging connector is abnormal (for example, the abnormal condition of overheat) according to the third temperature value, and closing the valve corresponding to the abnormal charging connector (S 17 ). 
     Incidentally, the above-mentioned sequence of measuring temperature values and pressure values and sequence of closing the valves are not limited to the present disclosure. Therefore, the liquid-cooled charging equipment with multiple charging connector assemblies can provide early warning and close the corresponding valve for the abnormal pipes and/or charging connectors in time by determining whether the pipe is in the abnormal condition of coolant leakage or overheat according to the results measured by the pressure sensors, the flow sensors, and the temperature sensors, thereby increasing the service life of charging connector assemblies and electric vehicles and ensure user safety, keeping other normal charging connector assemblies operating, and enhancing the usability and reliability of the liquid-cooled charging equipment with multiple charging connector assemblies. 
     In summary, the present disclosure has the following features and advantages. 
     1. By individually opening or closing the valve disposed in each coolant supply pipe, the coolant can be controlled to flow through the pipes corresponding to the charging connectors that needs to be cooled. 
     2. By using the unidirectional valve, the coolant can be prevented from flowing back to the pipe corresponding and to the charging connector assembly that does not need to be cooled. 
     3. By using the pressure sensor, the flow sensor, and the temperature sensor, it can be determined whether the coolant leakage of the pipe occurs and/or whether the overheat of the charging connector occurs so that the early warning, protection, and maintenance can be taken in time to increase the service life of charging connector assemblies and electric vehicles and ensure user safety. 
     4. The normal charging connector assemblies will not be affected by the abnormality of other charging connector assemblies during operation, which can increase the usability and reliability of the liquid-cooled charging equipment. 
     Although the present disclosure has been described with reference to the preferred embodiment thereof, it will be understood that the present disclosure is not limited to the details thereof. Various substitutions and modifications have been suggested in the foregoing description, and others will occur to those of ordinary skill in the art. Therefore, all such substitutions and modifications are intended to be embraced within the scope of the present disclosure as defined in the appended claims.