Patent Publication Number: US-2023144698-A1

Title: Ink Compositions

Description:
The present invention is relates to a heat exchanger, more particularly to a heat exchanger for an electrical element, particularly batter pack, to maintain homogenous temperature amongst the electrical element. 
     Generally, battery packs are provided in automobiles to supply power to various elements of the automobiles. While charging or discharging batteries provided in the battery packs, heat may be generated, which needs to controlled or reduced to have efficient charging and discharging of the batteries. Further, the temperature of the battery packs is to be maintained to increase service life of the battery pack. 
     To maintain the temperature of the battery pack at an optimum level, a heat exchanger can be provided on the battery pack, which exchanges heat generated in the battery pack with a coolant flowing through the heat exchanger to dissipate the heat generated in the battery pack. Further, the conventional heat exchanger may have uniform cooling channels throughout the heat exchanger, so the coolant entering into an inlet of the heat exchanger is colder than of the coolant flowing in the rest of heat exchanger. Hence, the conventional heat exchanger may cause different level of heat exchange between heat generated by battery cells and the coolant across the battery pack. As the heat exchanger provided with the battery pack may have uniform contact surface, uneven heat exchange may occur across the battery pack. Thereby, the battery pack may have different temperature at different regions of the battery pack, which results ineffective performance of the battery pack. Further, ineffective cooling of batteries may reduce service life of the battery pack. 
     Accordingly, there remains a need for a heat exchanger that maintains homogenous temperature across a battery pack. Further, there remains a need for heat exchanger that increase service life of the battery pack. 
     In the present description, some elements or parameters may be indexed, such as a first element and a second element. In this case, unless stated otherwise, this indexation is only meant to differentiate and name elements, which are similar but not identical. No idea of priority should be inferred from such indexation, as these terms may be switched without betraying the invention. Additionally, this indexation does not imply any order in mounting or use of the elements of the invention. 
     In view of the foregoing, an embodiment of the invention herein provides a heat exchanger for an electrical element. The heat exchanger includes a first plate, a second plate adapted to be thermally coupled with the electrical element, and a plurality of heat exchange channels. The plurality of heat exchange is defined between the first plate and the second plate to enable heat exchange between a fluid flowing in the plurality of heat exchange channels and the electrical element. The heat exchanger further includes a first portion and a second portion. The first portion of the heat exchange channels is in thermal contact with a first of the electrical elements and the second portion of the heat exchange channels is in thermal contact with a second of the electrical elements. Further, the first portion has an area different from the area of the second portion. 
     In one embodiment, wherein the first portion of the channels has variable cross-section and the second portion of the channels has constant cross-section. In another embodiment, the heat exchanger may include a third portion of channels having variable cross-section. 
     In one embodiment, the area of fluid contact surface in the first portion of the plurality of heat exchange channels to the electrical element is 3-20%, preferably 5 to 15%, smaller than the area of fluid contact surface in the second portion of the plurality of heat exchange channels to the electrical element. 
     In one example, the first plate comprising a second plate part and a first plate part having depressions that form the plurality of heat exchange channels. 
     In another example, the second plate comprises a first plate part and a second plate part, wherein the first plate parts of the first and second plates are spaced apart forming the plurality of heat exchange channels, and wherein the second plate parts of the first and second plates are bound together in a liquid tight manner. 
     Further, the second plate is in contact with the first plate to form the depression provided in the first plate as closed channels. 
     In yet another embodiment, the plurality of heat exchange channels is branched out, along the flow direction, as a tree from the first portion of the plurality of heat exchange channels. 
     In one aspect, the plurality of heat exchange channels is a U-shaped channel. Further, an inlet and an outlet are formed on one side of the heat exchanger. 
     In another aspect, the plurality of heat exchange channels is an I-shaped channel. Further, an inlet and an outlet are formed on opposite sides of the heat exchanger respectively. 
     In another aspect of the invention, a thermal system is provided. The thermal system includes a heat exchanger and an electrical element. Further, the electrical element is formed as multiple sets of battery spaced apart from each other and the electrical element is placed below and in thermal interaction with the first plate. 
     Further, the first portion of the plurality of heat exchange channels is adapted to be in contact with a first set of cells of the electrical element and the second portion of the plurality of heat exchange channels is adapted to be in contact with a second set of cells of the electrical element. 
     In another embodiment, a ratio between the first plate part and a second plate part in the first portion ( 108 ) of the plurality of heat exchange channels is smaller than 
     a ratio between the first plate part and a second plate part in the second portion of the plurality of heat exchange channels, is a range of 80% to 97%, preferably 95% to 85%, advantageously around 90%. 
    
    
     
       Other characteristics, details and advantages of the invention can be inferred from the description of the invention hereunder. A more complete appreciation of the invention and many of the attendant advantages thereof will be readily obtained as the same becomes better understood by reference to the following detailed description when considered in connection with the accompanying figures, wherein: 
         FIG.  1 A  illustrates a schematic representation of the heat exchanger, in accordance with an embodiment of the present invention; 
         FIGS.  1 B and  1 C  illustrate exploded views of the heat exchanger of  FIG.  1 A  without and with the battery pack respectively; 
         FIG.  2    illustrates a cross-sectional view of the heat exchanger of  FIG.  1 A  provided with a second plate; and 
         FIGS.  3 A-C  illustrate top views of channels of the heat exchanger of  FIG.  1 A , showing area of fluid contact surface of the channels at different sections along the length of the channels. 
     
    
    
     It must be noted that the figures disclose the invention in a detailed enough way to be implemented, the figures helping to better define the invention if needs be. The invention should however not be limited to the embodiment disclosed in the description. 
     The present invention relates to a heat exchanger for a battery pack having one or cells. The one or more cells are grouped together to form the battery pack. The batter pack may provide energy to electrical components of a vehicle. As the battery pack is main source for providing energy to the electrical components of the vehicle, the battery pack may get heated and temperature of the battery pack needs to be maintained at an optimum level for efficient performance of the cells. Further, the one or more cells in the battery pack may release different amount of heat and as such are at different temperatures, so a heat exchanger connected to the battery pack for cooling of the cells, should be able to uniformly cool the battery pack, so that the average temperature of the one or more cells are same. If cooling of the battery pack is uneven across the battery pack, attaining homogenous temperature across the battery pack is cumbersome. To achieve homogenous coolant flow rate across the heat exchanger, the heat exchanger is provided with non-identical coolant-contact surface between the heat exchanger and the batter pack. As the coolant flow rate in the heat exchanger is non-identical across the heat exchanger, the heat exchanger can cool the battery pack according to heat level released from corresponding cells of the battery pack, thereby attaining homogenous temperature across the battery pack. 
     While aspects relating to a heat exchanger having non-identical coolant-contact surface across the heat exchanger for a battery pack as described above and henceforth can be implemented for any other devices has heterogeneous temperature level across the devices to cool the device, the embodiments are described in the context of the following system(s). 
       FIGS.  1 A,  1 B and  1 C  illustrate different views of a heat exchanger  100  for an electrical element  102 , in accordance with an embodiment of the present invention. The electrical element  102  provides energy to any electrical components and emits heat while power the electrical components. In one example,  FIG.  1 A  illustrates a schematic view of the heat exchanger  100 , and  FIGS.  1 B and  1 C  illustrate exploded views of the heat exchanger  100  without and with the electrical element  102 . The electrical element  102  is a collection of cells serially arranged together, in a vehicle for providing electrical energy to the various components in the vehicle. The electrical element  102  may be provided in-contact with the heat exchanger  100  in order to enable heat exchange between the heat generated in the electrical element  102  and a coolant flowing in the heat exchanger  100 . In one embodiment, the electrical element  102  may include the cells  102 A,  102 B arranged serially and adapted to charge/discharge according to the requirements. While charging or discharging of the cells  102 A,  102 B in the electrical element  102 , the cells may release heat, which is undesirable. Further, the coolant flowing into the heat exchanger  100  may have different heat exchange capability at different location, since the temperature of the coolant is not same throughout the heat exchanger  100 . For example, the coolant entering through an inlet of the heat exchanger  100  is having less temperature level than of the coolant flowing at the body of the heat exchanger  100 . Whereas, the coolant coming out from an outlet of the heat exchanger  100  is having highest temperature than of the body of the heat exchanger  100 . Therefore, the heat exchange between the heat generated by the electrical element  102  and the coolant flowing in the heat exchanger  100  is non-uniform. Hence, the electrical element  102  may experience different temperature levels across the electrical element  102 . For example, the cells  102 A provided in the corners of the electrical element  102  may be in thermal contact with the coolant having lowest temperature and highest temperature, than of the coolant thermally contacting the cells  102 B provided in the electrical element  102 . Therefore heterogeneous heat exchange occurs across the electrical element  102 , which reduce the life span of the electrical element. To avoid such scenario, coolant contact surface across the heat exchanger is modified, so that the inlet area of the heat exchanger  100  and the outlet area have less flow of coolant than of rest of the heat exchanger  100 . 
     In one aspect of the invention, the heat exchanger includes a first plate  106  and a second plate  112  adapted to be coupled the first plate  106 . Further, a plurality of heat exchange channels  104  is defined on either of the first plate  106  or the second plate  112 . In one embodiment, the plurality of channels  104  can be formed partially on the first plate  106  and the second plate  112 . Further, the plurality of heat exchange channels  104  having different cross-sections are formed in the heat exchanger  100  to enable flow of the coolant in the plurality of heat exchange channels at different volumes and different flow rates. The plurality of heat exchange channels  104 , hereinafter referred to as channels, can be formed in the first plate  106  of the heat exchanger  100 . The first plate  106  may include a first plate part  106 A having depressions and a second plate part  106 . In one embodiment, the depressions formed in the first plate part  106 A of the first plate  106  may form the channels  104 , when the first plate  106  is coupled to the second plate  112 . The second plate  112  is formed in such a way that the first plate  106  is in contact with the electrical element  102 . In one embodiment, the second plate  112  may be in thermal contact to the electrical element  102 , to enable heat exchange between the electrical element  102  and the coolant flowing in the channels  104  of the heat exchanger  100 . In another example, the channels  104  may defined between the first plate  106  and the second plate  112  to enable heat exchange between the coolant and the electrical element  102 . In another example, the second plate  112  comprises a first plate part  112 A, and a second plate part  1128 . Further, the first plate parts  106 A,  112 A of the first  106  and second  112  plates are spaced apart forming the plurality of heat exchange channels, and the second plate parts  1068 ,  1128  of the first  106  and second  112  plates are bound together in a liquid tight manner. 
     The channels  104  defined in the first plate  106  may classified as a first portion of channels  108  and a second portion of channels  110 . In one embodiment, the first portion of channels  108  are having less cross section as comparted to the second portion of channels  110 , so that the first portion of channels  108  have different flow rate of the coolant from that of the second portion of channels  110 . In other words, the first portion of channels  108  has an area different from the area of the second portion of channels  110 , preferably first portion of channels  108  has less area than of the second portion of channels  110 . As the cross section of the first portion of channels  108  is lesser than of the second portion of channels  110 , heat exchange between the cells  102 A provided in the electrical element  102  corresponding to the first portion of channels  108  and the coolant flowing in the first portion of channels  108 , is low as compared to second portion of channels  110  of heat exchanger  100 . Further, the coolant flowing in the first portion of channels  108 , corresponding to the inlet, is colder than of the coolant flowing in the second portion of channels  110 . And, the coolant flowing in the first portion of channels  108 , corresponding to the outlet is hotter than of the coolant flowing in the second portion of channels  110 . Therefore, to attain uniform heat exchange between the electrical element  102  and the heat exchanger  100 , smaller cross-section of channels in the first portion of channels  108  is optimum than of the cross-section of channels in the second portion of channels  110 . Further, the first and second portions of channels  108 ,  110  are portions in thermal contact between the channels  104  and electrical elements  102 . In other words, the first portion of channels  108  corresponds to the sum of each individual portion of the channels  108 - 1 ,  108 - 2 ,  108 - 3  that are seen by the considered electrical element. 
     Further, the coolant flowing in the second portion of channels  110  is comparatively warmer than the coolant flowing in the first portion of channels  108 , so larger cross-section of channels in the second of portion channels  110  is required to cool the cells  102 B provided in the electrical element  102  to the nominal level. Thereby, the electrical element  102  is maintained at the nominal temperature throughout all the cells of the electrical element  102 . 
     In one embodiment, the channels  104  are engraved on the first plate  106  to form the channels  104  as semi-closed channels. In another embodiment, the channels  104  are formed by creating depression on the first plate part  106 A of the first plate  106  as shown in  FIG.  2   . Further, the second plate  112  is fixed on a side of the first plate  106  on which the depressions are provided, so that the depression can become as closed channels.  FIG.  2    illustrates a cross-sectional view of the heat exchanger  100  provided with the second plate  112 . Further, the second plate  112  is provided with the first plate  106  in such a way that the channels/depressions  104  on the first plates  106  and the second plate  112  forms closed channels to enable flow of the coolant there through. The second plate  112  may be in thermal contact with the electrical element  102  to enable heat exchange there-between. Further, the first portion of channels  108  are formed in such a way that the first portion of channels  108  are merged together to form a single channel. In other words, one end of the first portion of channels  108  may merged, along an opposite direction to a flow direction of the coolant, to form as a single channel. So formed signal channel enable introduction and reception of the coolant to and from the channels, and another end of the first portion of channels  108  are connected to the second portion of channels  110 . The first portion of channels  108  and the second portion of channels  110  are connected together to forms the channels  104 , which enable continuous flow of the coolant in the heat exchanger  100 . Further, the heat exchanger  100  and the electrical element  102  are collectively referred to as a thermal system. 
     The heat exchanger  100  may include of the at least one inlet  202  adapted to introduce the coolant to the channels  104  and of the at least one outlet  204  adapted to receive the coolant from the channels  104  after the coolant had extracted heat from the electrical element  102 . Further, the at least one inlet  202  and the at least one outlet  204  are formed on the first plate  106 . According to one aspect of invention, the at least one inlet  202  and the at least one outlet  204  are connected to the first portion of channels  108  to enable circulation of the coolant in the channels  104  of the heat exchanger  100 . In such cases, the second portion of channels  110  are U-shaped channels and connected to the first portion of channels  108  to form the channels  104 . As the first portion of channels  108  and the second portion of channels  110  are connected together, the channels  104  may include two ends such as a first end  206 A and a second end  206 B. Further, both the first end  206 A and the second end  206 B are in the first portion of channels  108  amongst the channels  104 , as shown in  FIG.  1 A . The at least one inlet  202  is connected to the first end  206 A of the channels  104  and the at least one outlet  204  is connected to the second end  206 B of the channels  104 . In such cases, the first end  206 A and the second  204 A of the channels  104  are merged together, along an opposite direction to a flow direction of the coolant, to form as single channel and connected to the at least one inlet  202  and the at least one outlets  204  respectively. Hence, the flow rate of the coolant in the first portion of channels  108  amongst the plurality of channels  104  is lower than of the second portion of channels  110 . As the first portion of channels  108  amongst the channels  104  is having less flow rate of the coolant than of the second portion of channels  110 , heat exchange in the first portion of channels  108  is lesser than of the second portion of channels  110 . Further, the channels  104  may be branched out, along the flow direction of the coolant, as a tree from an inlet amongst the set of inlets  202  in the first portion  108  of the plurality of heat exchange channels  104 . 
     According to another aspect of the invention, the set of inlets  202  is connected to the first portion of channels  108  and the set of outlets  204  is connected to the second portion of channels  110 . In such case, the second portion of channels  110  is I-shaped channels. Further, the set of inlets  202  may be formed on one end of the first plate  106  and connected to the first portion of channels  108 , and the set of outlet  204  may be formed on another end of the first plate  106  and connected to the second portion of channels  110 . The set of inlets  202  may be connected to conduits carrying the coolant and is adapted to introduce the coolant to the channels  104 . As the first portion of channels  108  amongst the channels  104  is having less flow rate of the coolant than of the second portion of channels  110 , heat exchange in the first portion of channels  108  is lesser than of the second portion of channels  110 . As the cells  102 A in the corner of the electrical element  102  emits less heat than the rest of the cells in the electrical element  102 , lesser heat exchange in the first portion of channels  108  than of the second portion of channels  110  is optimum to maintain average temperature across the electrical element  102 . 
       FIGS.  3 A-C  illustrate top views of the channels  104  of the heat exchanger  100  of  FIG.  1 A . The channels  104  of the heat exchanger  100  are super imposed on the cells  102 A of the electrical element  102 . The cells  102 A are serially arranged in rows in the electrical element  102 . The rows of cells  102 A are evenly spaced from one another in the electrical element  102  as shown in  FIGS.  3 A-C . For example,  FIG.  3 A-C  show the top views of the channels  104  showing coolant-contact surfaces  106 C and coolant non-contact surfaces  106 D of the channels  104  with the rows of cells  102 A. In other words, the first plate part  106 A is considered as the coolant-contact surfaces  106 C here, and the second plate part  106 B is considered as the coolant non-contact surfaces  106 D here. According to the aspect shown in  FIGS.  3 A-C , the channels  104  illustrated as three segments, such as a first segment  302  having four rows of cells  102 A as shown in  FIG.  3 A , a second segment  304  having three rows of cells  102 A as shown in  FIG.  3 B  and a third segment  306  having three rows of cells  102 A as shown in  FIG.  3 C . Further, the first portion of channels  108  are in the first segment as shown in  FIG.  3 A , and the second portion of channels  110  are shown in the all three segments. Further, the channels  104  corresponding to first two rows of cells  102 A are having less fluid contact surface area than of rest of rows of the cells  102 A. Further, the heat exchanger  100  can be divided into three zones, namely a first zone  310 , a second zone  312 , and a third zone  314 . Further, the rows  1 - 2  shown in  FIG.  3 A  are considered as the first zone  310 , rows  3 - 6  shown in  FIGS.  3 B-C  are considered as the second zone  312 , rows  7 - 8  shown in  FIG.  3 C  are considered as the third zone  314 . In one embodiment, coolant/fluid contact surface in the first zone  310  and the third zone  314  is less than of the second zone  312 . In this example, the first zone  310  includes the first portion of channels  108  and the second and third zones  312 ,  314  include the second portion of channels  110 . Further, a ratio between the first part plate  106 A/coolant-contact surfaces  302  and the second part plate  106 B/coolant non-contact surfaces  304  in the first zone  310  is 80%. Further, a ratio between the first part plate  106 A/coolant-contact surfaces  302  and the second part plate  106 B/coolant non-contact surfaces  304  in the second zone  312  is 100%. 
     As shown above, the first two of cells i.e., row  1  and  2 , are corresponding to the first portion of channels  108  which is having less fluid area than of the second portion of channels  110 . Rest of the rows of cells i.e., rows  3 - 8  are corresponding to the second portion of channels  110  which is having more fluid area. As the area fluid surface is less in the first portion of channels  108  than of the second portion of channels  110 , heat exchange between the heat exchanger  100  and the electrical element  102  is uniform across the electrical element  102 . The heat exchanger  100  cools the electrical element  102  to an average temperature across the electrical element  102 , irrespective of the cells  102 A in the electrical element emits heat at different temperature. Therefore, homogenous temperature of the cells in the electrical element  102  can be achieved, thereby increasing working life of the electrical element  102 . 
     Obviously, numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that the invention may be practiced otherwise than as specifically described herein. 
     In any case, the invention cannot and should not be limited to the embodiments specifically described in this document, as other embodiments might exist. The invention shall spread to any equivalent means and any technically operating combination of means.