Abstract:
A cooling system may be operable to cool a battery pack or other device through a heat exchange operation supported, at least in part, with cycling of a coolant relative to a coldplate or other thermally conducting surface of the device and/or attached thereto. The system may include a coldplate operable to exchange heat with a battery pack; and a coolant tank operable to exchange heat with the coldplate, the tank having a channel for directing a coolant flow in a direction from an inlet of the tank to at least one outlet of the tank and an inlet accumulator between the inlet and a beginning of the channel, wherein the inlet accumulator is wider along the coolant flow direction than the channel and the inlet and having a sloped side leading towards the channel configured to pool the coolant flow prior to entry into the channel.

Description:
TECHNICAL FIELD 
     The present invention relates to battery pack liquid cooling systems, such as but not limited to cooling systems suitable for use in cooling a Lithium-Ion (Li-Ion) battery used in electrically operable vehicles. 
     BACKGROUND 
     The use of a battery or grouping of batteries (battery pack) is common in vehicles and other devices. The battery pack can become heated during operation. Should the heating rise above desirable levels, the operation and/or capabilities of the battery pack and/or device may suffer. Accordingly, a need exists to provide a cooling system that is operable to cool or otherwise coolingly influence the battery pack to operate if possible, within a desired temperature ranges. 
     SUMMARY 
     One non-limiting aspect of the present invention contemplates to a battery pack liquid cooling system. The system may include: a coldplate operable to exchange heat with a battery pack; and a coolant tank operable to exchange heat with the coldplate, the coolant tank defining a channel for directing a coolant from an inlet to an outlet, the coolant tank including an inlet accumulator configured to pool the coolant prior to entry into the channel. 
     One non-limiting aspect of the present invention contemplates the inlet accumulator being configured to slow a velocity of the coolant received at the input prior to reaching the channel. 
     One non-limiting aspect of the present invention contemplates the coolant tank including an outlet accumulator configured to pool the coolant prior to entry into the outlet. 
     One non-limiting aspect of the present invention contemplates a cross-sectional area of each of the inlet and the outlet being less than a cross-sectional area of the corresponding inlet and outlet accumulator. 
     One non-limiting aspect of the present invention contemplates the inlet accumulator being configured to convert the coolant from a turbulent flow to a laminar flow. 
     One non-limiting aspect of the present invention contemplates the inlet accumulator being box-shaped with one side being sloped towards the channel. 
     One non-limiting aspect of the present invention contemplates the input accumulator including a port to the channel, the port having a cross-sectional area less than a cross-sectional area of the inlet accumulator. 
     One non-limiting aspect of the present invention contemplates the cross-sectional area of the port being less than a cross-sectional area of the inlet. 
     One non-limiting aspect of the present invention contemplates the inlet and the outlet being proximate a center of the coolant tank. 
     One non-limiting aspect of the present invention contemplates the outlet including a first outlet and a second outlet positioned on opposite sides of the first inlet. 
     One non-limiting aspect of the present invention contemplates the coolant flow channel proceeding in a serpentine pattern between the inlet and the first and second outlets. 
     One non-limiting aspect of the present invention contemplates the serpentine pattern being defined by a plurality of dividing walls, each dividing wall extending upwardly from a floor of the coolant tank to sealingly engage a bottom side of the coldplate. 
     One non-limiting aspect of the present invention contemplates a first portion of the plurality of dividing walls having a first length when measured lengthwise from the center to an outer edge of the coolant tank and a second portion of the plurality of the dividing walls having a second length when measured lengthwise from the center to the outer edge, the second length be less than 15% of the first length. 
     One non-limiting aspect of the present invention contemplates the second portion of the plurality of dividing walls being closer to the inlet than the first portion of the plurality of dividing walls when measured along the coolant flow channel from the inlet to the outlet. 
     One non-limiting aspect of the present invention contemplates a cooling system. The system may include: a coldplate operable to exchange heat with an object; and a coolant tank operable to exchange heat with the coldplate, the coolant tank defining a channel for directing a coolant from an inlet to at least one outlet, the coolant tank including an inlet accumulator configured to slow a velocity of the coolant received at the inlet prior reaching the channel. 
     One non-limiting aspect of the present invention contemplates the coolant tank including first and second outlets, wherein the channel divides proximate the input into corresponding first, second, third, and fourth serpentine patterns, the first and second serpentine patterns directing coolant to the first outlet and the third and fourth serpentine patterns directing coolant to the second outlet. 
     One non-limiting aspect of the present invention contemplates a battery pack liquid cooling system. The system may include: a coldplate operable to exchange heat with a battery pack; and a coolant tank operable to exchange heat with the coldplate, wherein the coolant tank includes a plurality of dividing walls arranged to define a channel for directing a coolant from an inlet to a first outlet and a second outlet, wherein the channel divides proximate the input into corresponding first, second, third, and fourth serpentine patterns, the first and second serpentine patterns directing coolant to the first outlet and the third and fourth serpentine patterns directing coolant to the second outlet. 
     One non-limiting aspect of the present invention contemplates the coolant tank including an accumulator between the inlet and the channel. 
     One non-limiting aspect of the present invention contemplates the accumulator being configured to slow a velocity of the coolant received at the inlet prior to entering the channel. 
     One non-limiting aspect of the present invention contemplates the accumulator being configured to pool coolant received at the inlet prior to entering the channel. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The present invention is pointed out with particularity in the appended claims. However, other features of the present invention will become more apparent and the present invention will be best understood by referring to the following detailed description in conjunction with the accompany drawings in which: 
         FIG. 1  illustrates a system having a battery pack cooled with a liquid cooling system as contemplated by one non-limiting aspect of the present invention. 
         FIGS. 2   a - 2   b  respectively illustrate top and bottom views of a coolant tank as contemplated by one non-limiting aspect of the present invention. 
         FIGS. 3   a - 3   b  and  4   a - 4   c  illustrate a coolant tank as contemplated by one non-limiting aspect of the present invention. 
         FIG. 5  illustrates a coolant tank as contemplated by one non-limiting aspect of the present invention. 
         FIG. 6  illustrates a coolant tank as contemplated by one non-limiting aspect of the present invention. 
         FIGS. 7   a - 7   b  illustrate a coolant tank as contemplated by one non-limiting aspect of the present invention 
     
    
    
     DETAILED DESCRIPTION 
     As required, detailed embodiments of the present invention are disclosed herein; however, it is to be understood that the disclosed embodiments are merely exemplary of the invention that may be embodied in various and alternative forms. The figures are not necessarily to scale; some features may be exaggerated or minimized to show details of particular components. Therefore, specific structural and functional details disclosed herein are not to be interpreted as limiting, but merely as a representative basis for teaching one skilled in the art to variously employ the present invention. 
       FIG. 1  illustrates a system  10  having a battery pack  12  cooled with a liquid cooling system  14  as contemplated by one non-limiting aspect of the present invention. The present invention is predominately described with respect to the liquid cooling system  14  being configured to facilitate cooling of the battery pack  12  for exemplary and non-limiting purposes. The present invention fully contemplates the liquid cooling system  14  being adapted to facilitate cooling of other devices. The illustrated battery pack  12  is shown to be of the type commonly found in vehicles to facilitate electric drive assist. The battery pack  12  is comprised of a plurality of storage cells  18 ,  20 ,  22  arranged with spacers  24 ,  26  therebetween and electrically interconnected with a plurality of busbars  30 ,  32  and positive and negative terminals  34 ,  36 . 
     The liquid cooling system  14  includes a coldplate  40  and a coolant tank  42 . The coldplate is shown to be configured to engage, adjoin, connect, or otherwise establish a thermally conducting boundary with the battery pack  12 . The coldplate  40  may be comprised of a thermally conducting material, such as but not limited to copper, aluminum, plastic, etc. The coldplate  40  may be attached directly to the battery  12  pack and/or indirectly by way of a battery pack support structure  44 . Preferably, the coldplate  40  is positioned relative to the battery pack  12  to maximize its heat exchanging capabilities. The coolant tank  42  is shown to be configured to facilitate the directing a coolant between an inlet  46  and an outlet  48 . The coolant travels through the coolant tank  42  in close proximity to the coldplate  40  to facilitate further heat exchange and cooling of the coldplate  40 , and thereby, the battery pack  12 . The liquid cooling system  14  and battery pack  12  may be included within an enclosure (not shown) or other non-illustrated arrangement. 
     A coolant delivery system  50  may be configured to facilitate cycling the coolant through the inlet  46  and the outlet  48 . The coolant delivery system  50  may be configured to pump a liquid coolant. Optionally, the coolant delivery system  50  may be configured to cycle non-liquid fluids, however, it is believed a liquid coolant would provide a more cost-effective cooling process relative to non-liquid fluids. The coolant delivery system  50  may include a de-gassing bottle or other device to remove air/bubbles from the coolant. The coolant delivery system  50  may also be configured to control a velocity and/or pressure at which coolant is delivered to the input  46 . The coolant delivery system  50  may include a controller (not shown) to control the coolant flow as a function of measured temperatures of the battery pack  12  and/or the coolant, such as to increase coolant flow in proportion to increases in temperature. The temperature based content can be performed in a step-wise, energy conservative fashion so that the desired temperature is maintained with the minimum amount of coolant flow, i.e., the coolant delivery system  50  may consume less energy when providing lower velocity/pressured coolant. 
       FIGS. 2   a - 2   b  respectively illustrate top and bottom views of a coolant tank  60  contemplated by one non-limiting aspect of the present invention. The coolant tank  60  includes a channel  62  for directing the coolant from the inlet  46  to the outlet  48 . The coolant tank  60  includes a plurality of dividing walls  66  extending upwardly from a floor  68  to engage a bottom of the coldplate  40 . The dividing walls  66  are shown to be arranged in a serpentine pattern between the inlet  46  and the outlet  48 . This serpentine pattern beneficially limits a temperature gradient widthwise between top and bottom sides  70 ,  72  of the coolant tank  60 . The coolant tank  60  is shown to include an inlet accumulator  74  between the inlet  46  and a beginning  76  of the channel  66  and an outlet accumulator  78  between an end  80  of the channel  66  and the outlet  46 . 
     The inlet accumulator  74  may be configured to pool the coolant received at the inlet  46  prior to being dispensed to the channel  66 . This pooling of the inlet accumulator  74  may be characterized by a velocity of the coolant received at the inlet  46  being slowed prior to entering the port/opening  76  to the channel  66 . This may be helpful in converting the coolant received at the inlet  46  from a turbulent flow to a laminar flow, which may limit eddies or other disruptions from generating bubbles or otherwise inducing cavitation. The outlet accumulator  78  may function in a similar manner to limit continued distribution of turbulent flow created within the channel  66  being carried back to the coolant delivery system  50 . The inlet and outlet accumulators  74 ,  76  may be generally box-shaped with a sloping side  82 ,  84  leading to the channel. The sloping sides  82 ,  84  can be provided to assist smoothing coolant flow through each accumulator  74 ,  76 . 
       FIGS. 3   a - 3   b  illustrate a coolant tank  90  contemplated by one non-limiting aspect of the present invention. The coolant tank  90  includes an additional outlet such that the coolant is directed from the inlet  46  equally to each of a first and second outlet  48 ′,  48 ″. The inlet and outlets  46 ,  48 ′,  48 ″ are positioned proximate a center of the coolant tank  90 . This central position is beneficially in centering the coldest coolant, i.e., that entering the inlet  46 , with a center of the battery pack  12 , which may help localize cooling relative the typically hottest portion of the battery pack  12 . As shown in more detail in  FIG. 3   b , the coolant tank  90  may include a plurality of dividing walls  94  extending upwardly from a floor  96  to sealingly engage the coldplate  40 . The dividing walls  94  may be arranged into first, second, third, and fourth serpentine patterned channels  96 ,  98 ,  100 ,  102  with the first and second patterns  96 ,  98  leading to the first outlet  48 ″ and the third and fourth patterns  100 ,  102  leading to the second outlet  48 ′. 
     A portion  106 ,  108  of the dividing walls  94  closest to the inlet  46  may be island-shaped such they having a length, as measured lengthwise from one side  112  to the other side  114  of the coolant tank  90 . The length of each island may be substantially less than the length of the other portion of dividing walls  94  that extend uninterrupted from the center to the sides  112 ,  114  to define each of the first, second, third, and fourth patterned channels  96 ,  98 ,  100 ,  102 . One non-limiting aspect of the present invention contemplates the use of the island-shaped dividing walls  106 ,  108  in order to further localize maximum cooling proximate central portions of the battery pack  12  where heating is likely to be greater. The islands  106 ,  108  achieve this by exposing more surface area of the coolant tank  90  to the coolant than the longer dividing walls. 
       FIG. 4   a  illustrates an exploded view of the coolant tank  90  to better illustrate the area of the coolant tank  90  proximate the inlet  46  and outlets  48 ′,  48 ″ in more detail. Each of the inlet  46  and outlets  48 ′,  48 ″ are shown to include an optional inlet and outlet accumulator  120 ,  122 ,  124 , similar to the accumulators described above. The inlet and outlet accumulators  120 ,  122 ,  124  may be configured to pool received coolant. The pooling may be characterized by a velocity of the received coolant being slowed prior to entering/leaving a port/opening to the channels  96 ,  98 ,  100 ,  102 . This may be helpful in converting the coolant from a turbulent flow to a laminar flow, which may limit eddies or other disruptions from generating bubbles or otherwise inducing cavitation. The inlet and outlet accumulators  120 ,  122 ,  124  may be generally box-shaped with a sloping side  130 ,  132 ,  134  engaging to the channels  96 ,  98 ,  100 ,  102 . The sloping sides  130 ,  132 ,  134  can be provided to assist smoothing coolant flow through each accumulator  120 ,  122 ,  124 . 
       FIG. 4   b  illustrates a partial cross-section as taken lengthwise through the inlet  46 . This view illustrates a cross-sectional area A of the inlet  46 , as measured lengthwise from side to side  112 ,  114  of the coolant tank  90  being less than a cross-sectional area B of the inlet accumulator  120 . It also illustrates the cross-sectional area A of the inlet accumulator  120  being greater than a cross-sectional area C of the channel as measured widthwise from top  130  to bottom  132  of the coolant tank  90 .  FIG. 4   c  illustrates a partial cross-section as taken widthwise through the inlet  46 , the first outlet  48 ″, and the second outlet  48 ′. This view illustrates a cross-sectional area E of the first and second outlets  48 ′,  48 ″, as measured widthwise from the top  130  to the bottom  132  of the coolant tank  90 , having cross-sectional area E less than the corresponding cross-sectional area D of the accumulators  122 ,  124 . It also illustrates the cross-sectional area D of the accumulators  122 ,  124  being greater than a cross-sectional area F of the associated channel as measured in the same direction widthwise from the top to the bottom  130 ,  132  of the coolant tank  90 . 
       FIG. 5  illustrates a coolant tank  140  in accordance with one non-limiting aspect of the present invention. The coolant tank  140  is shown to include a plurality of dividing walls arranged into a baffled configuration to guide the coolant from an inlet to an outlet. While not shown, the inlet and outlet may include accumulators similar to those described above.  FIG. 6  illustrates a coolant tank  142  in accordance with one non-limiting aspect of the present invention. The coolant tank is shown to include a plurality of dividing walls arranged into a spiraled configuration to guide the coolant from an inlet to an outlet. While not shown, the inlet and outlet may include accumulators similar to those described above.  FIGS. 7   a - 7   b  illustrates a coolant tank  144  in accordance with one non-limiting aspect of the present invention. The coolant tank is shown to include a plurality of dividing walls arranged into a plurality of concentric squares configuration to guide the coolant from an inlet to one of two outlets. 
     As supported above, one non-limiting aspect of the present invention contemplate a liquid cooling system that is operable to facilitate thermal management of Li-Ion battery pack. The present invention may be helpful in limiting the number of coolant line connections (e.g., 2-3 connections), reducing the chances of coolant leaks, and sealing/isolating the cooling system from a high voltage system, and limiting cost and weight. 
     While exemplary embodiments are described above, it is not intended that these embodiments describe all possible forms of the invention. Rather, the words used in the specification are words of description rather than limitation, and it is understood that various changes may be made without departing from the spirit and scope of the invention. Additionally, the features of various implementing embodiments may be combined to form further embodiments of the invention.