Patent Publication Number: US-2022212566-A1

Title: Selective thermal mechanization for ress heat loads

Description:
INTRODUCTION 
     The present disclosure relates to mechanisms and assemblies selectively cooling heat loads from rechargeable energy storage systems (RESS), such as for electric vehicles. 
     SUMMARY 
     A vehicle and method for cooling portions of the vehicle are provided. The vehicle includes a plurality of low temperature radiators (LTR), a plurality of valves, and a rechargeable energy storage system (RESS). The vehicle also includes an i-condenser, or indirect condenser, coolant circuit and a RESS coolant circuit. A controller is configured to control the valves to route coolant flow, and to compare ambient temperature to a target low temperature and a target high temperature. 
     The RESS may be selectively cooled by comparing ambient temperature to the target low temperature and the target high temperature. If the ambient temperature is below the target low temperature, coolant flow is routed through a first flow path that places a first LTR and a second LTR in the RESS coolant circuit. If the ambient temperature is between the target low temperature and the target high temperature, coolant flow is routed through a second flow path that places the first LTR in the RESS coolant circuit and the second LTR in the i-condenser coolant circuit. If the ambient temperature is above the target high temperature, coolant flow is routed through a third flow path that places the first LTR and the second LTR in the i-condenser coolant circuit. The i-condenser coolant circuit may also pass through a third LTR. 
     In some configurations, the first LTR is a first LTR set having at least two LTR, the second LTR is a second LTR set having at least two LTR, and the third LTR is a third LTR set having at least two LTR. Additionally, each of the LTR sets may be aligned in parallel relative to coolant flow. 
     The controller may also determine a driving aggressiveness level. From that aggressiveness level, or from coolant temperatures at the RESS, the controller may adjust the target low temperature and the target high temperature, such that there is, at least, a racing target low temperature and a racing target high temperature, and a continuous target low temperature and a continuous target high temperature. The continuous target low temperature is lower than the racing target low temperature, and the continuous target high temperature is lower than the racing target high temperature. 
     The above features and advantages and other features and advantages of the present disclosure are readily apparent from the following detailed description of the best modes for carrying out the disclosure when taken in connection with the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic diagram of a vehicle having one or more RESS, one or more cooling circuits, and one or more low temperature radiators (LTR). 
         FIG. 2  is a schematic diagram of a first flow path for the cooling circuits of the vehicle. 
         FIG. 3  is a schematic diagram of a second flow path for the cooling circuits of the vehicle. 
         FIG. 4  is a schematic diagram of a third flow path for the cooling circuits of the vehicle. 
     
    
    
     DETAILED DESCRIPTION 
     Referring to the drawings, like reference numbers refer to similar components, wherever possible.  FIG. 1  schematically illustrates a vehicle  10 , shown highly schematically, which may be, for example and without limitation, an electric or hybrid-electric vehicle. The vehicle  10  includes a rechargeable energy storage system (RESS)  12 , which may include, for example and without limitation, a rechargeable battery or rechargeable battery pack. 
     A control system or controller  14  is operatively in communication with all necessary components of the vehicle  10 . The controller  14  includes a non-generalized, electronic control device having a preprogrammed digital computer or processor, a memory or non-transitory computer readable medium used to store data such as control logic, instructions, lookup tables, etc., and a plurality of input/output peripherals, ports, or communication protocols. The controller  14  is configured to implement or execute the control logic or instructions described herein. 
     Furthermore, the controller  14  may include, or be in communication with, a plurality of sensors, including, without limitation, those configured to sense or estimate ambient temperature outside of the vehicle  10  and various coolant temperatures within the vehicle  10 . The controller  14  may be dedicated to the specific aspects of the vehicle  10  described herein, or the controller  14  may be part of a larger control system that manages numerous functions of the vehicle  10 . 
     The drawings and figures presented herein are diagrams, are not to scale, and are provided purely for descriptive purposes. Thus, any specific or relative dimensions or alignments shown in the drawings are not to be construed as limiting. While the disclosure may be illustrated with respect to specific applications or industries, those skilled in the art will recognize the broader applicability of the disclosure. Those having ordinary skill in the art will recognize that terms such as “above,” “below,” “upward,” “downward,” et cetera, are used descriptively of the figures, and do not represent limitations on the scope of the disclosure, as defined by the appended claims. Any numerical designations, such as “first” or “second” are illustrative only and are not intended to limit the scope of the disclosure in any way. 
     Features shown in one figure may be combined with, substituted for, or modified by, features shown in any of the figures. Unless stated otherwise, no features, elements, or limitations are mutually exclusive of any other features, elements, or limitations. Furthermore, no features, elements, or limitations are absolutely required for operation. Any specific configurations shown in the figures are illustrative only and the specific configurations shown are not limiting of the claims or the description. 
     All numerical values of parameters (e.g., of quantities or conditions) in this specification, including the appended claims, are to be understood as being modified in all instances by the term about whether or not the term actually appears before the numerical value. About indicates that the stated numerical value allows some slight imprecision (with some approach to exactness in the value; about or reasonably close to the value; nearly). If the imprecision provided by about is not otherwise understood in the art with this ordinary meaning, then about as used herein indicates at least variations that may arise from ordinary methods of measuring and using such parameters. In addition, disclosure of ranges includes disclosure of all values and further divided ranges within the entire range. Each value within a range and the endpoints of a range are hereby all disclosed as separate embodiments. 
     When used herein, the term “substantially” refers to relationships that are ideally perfect or complete, but where manufacturing realties prevent absolute perfection. Therefore, substantially denotes typical variance from perfection. For example, if height A is substantially equal to height B, it may be preferred that the two heights are 100.0% equivalent, but manufacturing realities likely result in the distances varying from such perfection. Skilled artisans will recognize the amount of acceptable variance. For example, and without limitation, coverages, areas, or distances may generally be within 10% of perfection for substantial equivalence. Similarly, relative alignments, such as parallel or perpendicular, may generally be considered to be within 5%. 
     The vehicle  10  includes an improved cooling system  20  for the RESS  12 , in addition to other systems of the vehicle  10 . The cooling system  20  includes several low temperature radiators (LTR), many of which are selectively moveable between different cooling circuits. In most configurations, the front of the vehicle  10  will be to the left, as viewed in  FIG. 1 . 
     The cooling system  20  includes, at least, a refrigerant circuit  22 , a RESS coolant circuit  24 , and an i-condenser coolant circuit  26 . The refrigerant circuit  22 , RESS coolant circuit  24 , and i-condenser coolant circuit  26  are illustrated in more detail, including some of the possible flow paths, in the diagrams of  FIGS. 2-4 . As used herein, the term i-condenser refers, in general, to an indirect condenser or a water-cooled condenser. The i-condenser may be, for example and without limitation, a refrigerant vapor to liquid coolant (i.e., water) heat exchanger, and the i-condenser coolant circuit  26  includes at least one such component, as discussed herein. 
     The plurality of LTR used by the cooling system  20  may be referred to as radiators and may be combined or grouped to form LTR sets. A first LTR, or first radiator  32 , and a second LTR, or second radiator  34 , form what may be referred to as a first LTR set  35 . A third LTR, or third radiator  36 , and a fourth LTR, or fourth radiator  38 , form what may be referred to as a second LTR set  39 . Similarly, a fifth LTR, or fifth radiator  40 , and a sixth LTR, or sixth radiator  42 , form what may be referred to as a third LTR set  43 . Various fans, conduits, or other structures may be used to selectively control air flow to the various radiators or LTR sets. 
     Referring to  FIGS. 2-4 , with continued reference to  FIG. 1 , there are shown schematic diagrams of different flow paths through the cooling system  20 , each of which varies the LTR used by the different cooling circuits.  FIG. 2  schematically illustrates a first flow path (or flow path  1 ) for the cooling circuits of the illustrative vehicle  10 ;  FIG. 3  schematically illustrates a second flow path (or flow path  2 ) for the cooling circuits of the illustrative vehicle  10 ; and  FIG. 4  schematically illustrates a third flow path (or flow path  3 ) for the cooling circuits of the illustrative vehicle  10 . The three flow paths shown in the figures are illustrative only, and skilled artisans will recognize that additional flow paths, and modifications to the those shown, may be used within the scope described herein. 
       FIGS. 2-4  illustrate various methods or algorithms for cooling the RESS  12 , in addition to other components of the vehicle, by selectively changing how the LTR, or LTR sets, are utilized by the vehicle  10  and the cooling system  20 . Generally, the functions or methods described herein may be executed in response to commands from the controller  14 , which is in communication with the necessary components and able to execute all necessary functions described herein. As discussed herein, selection of the example flow paths may be based on the, for example, and without limitation, temperature of the RESS  12 , the ambient temperature, and driving styles or aggressiveness. 
     As shown in  FIGS. 2-4 , the cooling system  20  includes several other components, some of which, but not all, are individually numbered or shown. A first valve  52 , a second valve  54 , third valve  56 , and a fourth valve  58  are selectively changed by the controller  14  to route coolant flow through the various LTR or LTR sets. In the schematic diagrams of  FIGS. 2-4 : flow through the refrigerant circuit  22  is shown with long-dashed lines; flow through the RESS coolant circuit  24  is shown with solid lines; and flow through the i-condenser coolant circuit  26  is shown in with short-dashed lines. Note that the valves are not shown in detail and are illustrated only as examples of switching devices that alter the flow of the coolant—skilled artisans will recognize suitable structures to affect the described functions. 
     The refrigerant circuit  22  operates as an air conditioner system, such as a heat pump, and includes a chiller  60 , which is a refrigerant to coolant heat exchanger. The chiller  60  sits between the RESS coolant circuit  24  and the refrigerant circuit  22 . The cooling system  20  also includes one or more pumps, which are shown by pump symbols and are not individually numbered. 
     An i-condenser  62  sits, and exchanges heat, between the refrigerant circuit  22  and the i-condenser coolant circuit  26 . The i-condenser  62  illustrated schematically in  FIGS. 2-4  is a refrigerant vapor to liquid coolant heat exchanger. However, the i-condenser  62  may be representative of other heat exchange structures. The i-condenser  62  may operate more efficiently than vapor to air heat exchangers used in some air conditioner system configurations. Not all parts of the refrigerant circuit  22  are separately shown, but skilled artisans will recognize the functioning, components, and operation thereof, including one or more compressors  64  and evaporators  66 . 
       FIG. 2  shows the first flow path as an example method of cooling the RESS  12 . The controller  14  may be comparing ambient temperature to a target low temperature and a target high temperature. Where the ambient temperature is below the target low temperature, the controller  14  routes coolant flow through the first flow path. 
     The first flow path places the first LTR set  35 , including the first radiator  32  and the second radiator  34 , in the RESS coolant circuit  24 . Additionally, the first flow path places the second LTR set  39 , including the third radiator  36  and the fourth radiator  38 , in the RESS coolant circuit  24 . 
     When the ambient temperature is relatively low, such that it is below the target low temperature, there is a relatively large temperature differential between the coolant flowing out from the RESS  12  and the ambient air. Therefore, significant cooling is achieved by including the first LTR set  35  and the second LTR set  39  in the RESS coolant circuit  24 , as illustrated by the solid lines. 
     After passing through the first LTR set  35  and the second LTR set  39 , the coolant of the RESS coolant circuit  24  also passes through the chiller  60 , where it is further cooled by the heat pump system of the refrigerant circuit  22 . The i-condenser coolant circuit  26  utilizes the third LTR set  43 , including the fifth radiator  40  and the sixth radiator  42  to expel heat transferred from the refrigerant circuit  22 . 
     In one operating example illustrated by  FIG. 2 , where the ambient temperature is below 30 C and the coolant leaving the RESS  12  is approximately 40 C, the first LTR set  35  and the second LTR set  39  may collectively remove up to 40 kW of heat power from the RESS coolant circuit  24 . Furthermore, the refrigerant circuit  22 , which expels heat energy through the i-condenser coolant circuit  26 , may remove up to 30 kW of heat power from the RESS coolant circuit  24  via the chiller  60 . 
     If the ambient temperature is between the target low temperature and the target high temperature, the controller  14  routes coolant flow through the second flow path, as shown in  FIG. 3 . The second flow path places the first LTR set  35 , including the first radiator  32  and the second radiator  34 , in the RESS coolant circuit  24 . However, the second flow path places the second LTR set  39 , including the third radiator  36  and the fourth radiator  38 , in the i-condenser coolant circuit  26 . 
     When the ambient temperature is relatively moderate, there is a smaller temperature differential between the coolant flowing out of the RESS  12  and the ambient air. Therefore, less cooling is achieved by passing coolant in the RESS coolant circuit  24  through both the first LTR set  35  and the second LTR set  39 . Therefore, the second flow path utilizes the second LTR set  39  for expelling the heat passed from the refrigerant circuit  22  to the i-condenser coolant circuit  26 . 
     In the second flow path, the fourth valve  58  sends coolant flow from the third LTR set  43  to the second valve  54 , which directs coolant flow through the second LTR set  39 . The coolant flow in the i-condenser coolant circuit  26  is further cooled by the second LTR set  39 . The third valve then directs coolant from the second LTR set  39  back toward the i-condenser  62  via the fourth valve  58 . The second valve  54  directs coolant flow within the RESS coolant circuit  24  to the third valve  56 , where it is returned to the chiller  60 , which expels heat to the refrigerant circuit  22 . 
     In one operating example illustrated by  FIG. 3 , where the ambient temperature is between 30 C and 38 C, and the coolant leaving the RESS  12  is approximately 40 C, the first LTR set  35  removes up to 10 kW of power from the RESS coolant circuit  24 . Compare this to the 40 kW of power removed via the first LTR set  35  and the second LTR set  39  at the lower ambient temperatures that are used with the first flow path. 
     However, by moving the second LTR set  39  to the i-condenser coolant circuit  26 , the refrigerant circuit  22  can expel more heat energy with both the second LTR set  39  and the third LTR set  43  in the i-condenser coolant circuit  26 , such that the chiller  60  may remove up to 35 kW of power from the RESS coolant circuit  24 . Moving the second LTR set  39  into the i-condenser coolant circuit  26  enhances the heat rejection capability of the chiller  60 . Therefore, the power removal through the chiller  60  in the second flow path is greater than that of the first flow path. 
     When the ambient temperature is above the target high temperature, the controller  14  routes coolant flow through the third flow path, as shown in  FIG. 4 . The third flow path places both the first LTR set  35  and the second LTR set  39  in the i-condenser coolant circuit  26 . When the ambient temperature is relatively high but still less than the temperature of the RESS  12  coolant, there is very little temperature differential between the coolant flowing out of the RESS  12  and the ambient air. Therefore, less cooling is achieved by passing coolant in the RESS coolant circuit  24  through the first LTR set  35  or the second LTR set  39 . 
     The third flow path utilizes both the first LTR set  35  and the second LTR set  39  for expelling the heat passed from the refrigerant circuit  22  to the i-condenser coolant circuit  26 . Moving the first LTR set  35  and the second LTR set  39  into the i-condenser coolant circuit  26  further enhances the heat rejection capability of the chiller  60 . Therefore, the heat removal through the chiller  60  in the third flow path is greater than that of either the first flow path or the second flow path. 
     In one operating example illustrated by  FIG. 4 , where the ambient temperature is above 38 C, and the coolant leaving the RESS  12  is approximately 40 C, there is little or no temperature differential between the coolant of the RESS  12  and the ambient air such that the RESS coolant circuit  24  utilizes neither the first LTR set  35  nor the second LTR set  39  in the third flow path. When the ambient temperature is higher than the RESS  12  coolant temperature, no cooling can be achieved by passing the coolant flowing out of the RESS  12  through the first LTR set  35  and the second LTR set  39 . However, the refrigerant circuit  22  can expel more heat energy with the first LTR set  35 , the second LTR set  39 , and the third LTR set  43  within the i-condenser coolant circuit  26 , such that the chiller  60  may remove up to 40 kW of power from the RESS coolant circuit  24 . 
     The specific operating examples discussed above relative to  FIGS. 2-4  may be occur during extreme or excursion situations. For example, the coolant out temperature of the RESS  12  may reach 40 C or higher during race track, or other highly aggressive, driving situations. During the excursion situations, it may be preferred that the RESS  12  reaches temperatures no greater than 45-50 C—note that the coolant passing through the RESS  12  will be at slightly lower temperature than the RESS  12 , itself, due to imperfect heat transfer therebetween. 
     Therefore, under racing conditions, where the coolant out temperature of the RESS  12  may reach 40 C, the controller  14  may select the flow paths according to the following: flow path  1  when the ambient temperature is below 30 C (i.e., a racing target low temperature); flow path  2  when the ambient temperature is between 30 C and 38 C (i.e., a racing target high temperature); and flow path  3  when the ambient temperature is above 38 C. 
     As contrasted with extreme or racing conditions, the vehicle  10  may also be used in continuous operation conditions. The continuous conditions may include mildly aggressive driving, but these conditions may generally be within the constraints of street or highway driving situations. 
     Under continuous driving situations, it may be preferred that the RESS  12  reaches temperatures no greater than 35 C to limit wear on the RESS  12 . Therefore, the coolant out temperature of the RESS  12  may reach 30 C during continuous driving conditions. In response, the controller  14  may adjust the target low temperature and the target high temperature to better exchange heat energy with the surrounding ambient conditions. 
     Therefore, under continuous conditions, where the coolant out temperature of the RESS  12  may reach 30 C—due to imperfect heat transfer from the RESS  12 —the controller  14  may select the flow paths according to the following: flow path  1  when the ambient temperature is below 20 C (i.e., a continuous target low temperature, which is lower than the racing target low temperature); flow path  2  when the ambient temperature is between 20 C and 28 C (i.e., a continuous target high temperature, which is lower than the racing target high temperature); and flow path  3  when the ambient temperature is above 28 C. 
     While varying the target low temperature and the target high temperature has been discussed herein relative to the driving conditions, particularly with an aggressiveness rating relative to either racing or continuous operation, alternative triggers may be used. For example, and without limitation, varying the target low temperature and the target high temperature may occur in response to the coolant out temperature of the RESS  12 , or in response to the coolant temperature exiting the chiller  60 —i.e., the coolant in temperature to the RESS  12 . For example, when the coolant out temperature from the RESS  12  is 40 C, the controller  14  may use the higher target temperatures, but when the coolant out temperature from the RESS  12  is 30 C, the controller  14  may use the lower target temperatures. 
     Note that single, and possibly larger in size or differently configured, radiators may be used in place of the LTR sets shown. For example, and without limitation, the first radiator  32  may replace the first LTR set  35 , the fourth radiator  38  may replace the second LTR set  39 , and the fifth radiator  40  may replace the third LTR set  43 , possibly with those single components staying in the same general location of the schematic flow patterns shown in  FIGS. 2-4  and placement within the vehicle  10  shown in  FIG. 1 . 
     Furthermore, airflow through the radiators of the example vehicle  10  shown in the diagram of  FIG. 1  is in series, but other configurations may be used. The ordering, or alignment, of the individual radiators shown in  FIG. 1  is selected based, in part, on improved utilization of temperature differentials. For example, the third radiator  36  is located in front, relative to airflow, of the fifth radiator  40 . Coolant flow through the third radiator  36  will be at a lower temperature than coolant flow through the fifth radiator  40 , which is nearer to the heat transferred from the refrigerant circuit  22  to the i-condenser  62 . Therefore, if the third radiator  36  raises the temperature of the airflow passing therethrough, the coolant temperature of the fifth radiator  40  will likely still have a temperature differential with the warmed air, such that heat transfer still occurs across the fifth radiator  40 . 
     As illustrated in  FIGS. 2-4 , coolant flow through the first LTR set  35  is aligned in parallel, the second LTR set  39  is aligned in parallel, and the third LTR set  43  is aligned in parallel. However, this coolant flow alignment is not required. In some configurations, the LTR sets could be aligned in series. Additionally, while  FIGS. 2-4  schematically illustrate the individual radiators as similar-sized boxes, the actual radiators may have very different sizes, shapes, or styles. 
     The detailed description and the drawings or figures are supportive and descriptive of the subject matter herein. While some of the best modes and other embodiments have been described in detail, various alternative designs, embodiments, and configurations exist. 
     Furthermore, any embodiments shown in the drawings or the characteristics of various embodiments mentioned in the present description are not necessarily to be understood as embodiments independent of each other. Rather, it is possible that each of the characteristics described in one of the examples of an embodiment can be combined with one or a plurality of other desired characteristics from other embodiments, resulting in other embodiments not described in words or by reference to the drawings. Accordingly, such other embodiments fall within the framework of the scope of the appended claims.