Modular heat exchangers for battery thermal modulation

A modular heat exchanger for battery thermal management having a plurality of similarly constructed heat exchange elements affixed to a cover plate and fluidly coupled with one another via a single external manifold structure that functions as both an inlet manifold and an outlet manifold for each of the heat exchange elements. Rigidity is improved with alternating tabs or overlapping tabs between adjacent elements, and/or side edges between adjacent elements having cutouts for receiving stiffening ribs formed in the cover plate. The external manifold structure provides additional stiffening for the interconnected heat exchange elements.

TECHNICAL FIELD

The present disclosure relates to heat exchangers for thermal management of rechargeable batteries within an energy storage system of a battery electric vehicle (BEV) or hybrid electric vehicle (HEV), and particularly to such heat exchangers having a modular construction and including multiple heat exchanger elements.

BACKGROUND AND SUMMARY

Energy storage systems such as those used in BEVs and HEVs comprise rechargeable lithium-ion batteries. A typical rechargeable battery for a BEV or HEV will comprise a number of battery modules which are electrically connected together in series and/or in parallel to provide the battery with the desired system voltage and capacity. Each battery module comprises a plurality of battery cells which are electrically connected together in series and/or parallel, wherein the battery cells may be in the form of pouch cells, prismatic cells or cylindrical cells. The operation of the battery may be endothermic or exothermic, depending on temperature conditions.

A thermal modulation system for a rechargeable vehicle battery may comprise a plurality of “cold plate” heat exchangers. Each cold plate has a flat upper surface on which one or more battery cells and/or battery modules is supported, the cells and/or modules being in thermal contact with a heat transfer fluid circulating through one or more fluid flow passages inside the cold plate.

A cold plate is commonly constructed from a cover plate defining the flat upper surface, and a shaped base plate having a plurality of ridges which define the fluid flow passages, with the cover plate and base plate being joined by brazing in a brazing furnace. A typical thermal modulation system may comprise a plurality of such conventional cold plates joined together in series and/or parallel by conduits and fluid connections.

It may be advantageous to replace multiple conventional cold plates with a smaller number of larger cold plates, to improve reliability and reduce cost and complexity, by reducing the number of components and the number of leak-prone fluid connections between cold plates. However, there are several limitations which practically limit the size of conventionally constructed, brazed cold plates. For example, specialized equipment such as large presses are required for forming the ridges in large sized plates. In addition, the amount of energy required to heat the cold plate components to brazing temperatures increases with size. Also, furnace size may also be limited, thereby making furnace brazing of large cold plates difficult and/or uneconomical.

It is known to braze a plurality of conventionally sized base plates, with ridges formed by conventional tooling, to a single flat top plate, thereby allowing the overall size of the heat exchanger to be somewhat increased without incurring the added cost of re-tooling. This modular construction is known from commonly assigned U.S. patent application Ser. No. 14/972,463, published as US 2016/0204486 A1, which is incorporated herein by reference in its entirety.

However, there is a continued need for improved modular constructions for battery heat exchangers such as cold plates, so as to increase size of the cold plates, to improve flexibility in designing cold plates for specific applications, to improve reliability, and to allow for cost effective manufacture of larger cold plates.

To address at least some of the aforementioned problems, and in accordance with an aspect of the present disclosure, there is provided a heat exchanger, comprising a plurality of heat exchanger elements. Each of the heat exchanger elements preferably comprises: (i) a first plate having an inner surface and an outer surface; (ii) a second plate having an inner surface and an outer surface, wherein the first and second plates are joined together with their inner surfaces in opposed facing relation to one another, and with portions of the inner surfaces being spaced apart from one another; (iii) at least one fluid flow passage adapted for flow of a heat transfer fluid, and located between the spaced apart portions of the inner surfaces of the first and second plates; (iv) at least one first inlet port for supplying the heat transfer fluid to the plurality of fluid flow passages; and (v) at least one first outlet port for discharging the heat transfer fluid from the plurality of fluid flow passages.

According to an aspect, the heat exchanger further comprises an external manifold portion comprising: (i) a second inlet port for supplying the heat transfer fluid to the external manifold portion; (ii) a second outlet port for discharging the heat transfer fluid from the external manifold portion; (iii) an inlet manifold channel in fluid communication with the at least one first inlet port of each heat exchanger element and with the second inlet port of the external manifold portion; and (iv) an outlet manifold channel in fluid communication with the at least one first outlet port of each heat exchanger element and with the second outlet port of the external manifold portion.

According to an aspect, the plurality of heat exchanger elements are arranged in a substantially planar array, and wherein the heat exchanger further comprises at least one stiffening elements arranged between adjacent heat exchanger elements in the array, to limit deflection between the adjacent heat exchanger elements in the array.

According to an aspect, the second plate of each heat exchanger element includes a planar peripheral flange surrounding the at least one fluid flow passage; wherein the peripheral flange defines a sealing surface along which the inner surface of the second plate is sealingly joined to the inner surface of the first plate; wherein the first plate has a sealing surface along which the inner surface of the first plate is sealingly joined to the sealing surface of the second plate; and wherein at least one of the first plate and the second plate includes a pair of side edges, wherein the side edges of the second plate are defined by opposed outer edges of the peripheral flange.

According to an aspect, at least one of the side edges includes at least one outermost edge portion, each of which extends along at least a portion of the side edge, and an innermost edge portion extending along at least a portion of the side edge, wherein a first axis is defined along the at least one outermost edge portion, and a second axis is defined along the at least one innermost edge portion; wherein the second plates of the heat exchanger elements are arranged side-by-side such that each of the second plates has at least one of its side edges positioned with its first axis located between the first and second axes of the side edge of an adjacent one of the second plates, the side edges of adjacent pairs of second plates being substantially co-planar with one another.

According to an aspect, the first and second axes are parallel to one another, and transverse to an axis along which the external manifold extends.

According to an aspect, at least one of the side edges includes a plurality of outermost edge portions and a plurality of innermost edge portions, wherein the outermost and innermost edge portions alternate with one another along a length of the at least one side edge; wherein the outermost edge portions and the innermost edge portions have a complementary arrangement and shape, such that each of the outermost edge portions defines a male portion and each of the innermost edge portions defines a female portion in which the male portion is received, so as to provide a plurality of stiffening elements; wherein a gap is provided between adjacent pairs of side edges, the gap being tortuous and following along the innermost and outermost edge portions of the side edges.

According to an aspect, the first plates of the plurality of heat exchanger elements are integrally connected together to provide an integral first plate to which all the second plates are sealingly joined; wherein the integral first plate has an area which is at least as great as a combined area of the plurality of second plates.

According to an aspect, the first plates of the plurality of heat exchanger elements are separately formed, such that both the first plate and the second plate of each heat exchanger element include a pair of said side edges; wherein, within each of the heat exchanger elements, each of the innermost edge portions of the first plate overlies one of the outermost edge portions of the second plate, and each of the outermost edge portions of the first plate overlies one of the innermost edge portions of the second plate, so as to provide alternating upper and lower rows of projecting tabs along the side edges of the first and second plates; wherein, with the heat exchanger elements arranged side-by-side in the array, an adjacent pair of the heat exchanger elements is arranged with the upper row of projecting tabs of a first heat exchanger element overlapping the lower row of projecting tabs of an adjacent second heat exchanger element, and with the upper row of projecting tabs of the second heat exchanger element overlapping the lower row of projecting tabs of the first heat exchanger element.

According to an aspect, the upper row of projecting tabs of the first heat exchanger element is substantially co-planar with the upper row of projecting tabs of the second heat exchanger element; and wherein the lower row of projecting tabs of the first heat exchanger element is substantially co-planar with the lower row of projecting tabs of the second heat exchanger element.

According to an aspect, the overlapping projecting tabs of the first and second heat exchanger elements are secured together.

According to an aspect, the first plates of the plurality of heat exchanger elements are separately formed, such that both the first plate and the second plate of each heat exchanger element include a pair of side edges; wherein an upper or lower projecting tab is defined along at least one side of each of the heat exchanger elements, each upper projecting tab being formed by a portion of the first plate, inward of one of the side edges of the first plate, projecting outwardly beyond the side edge of the second plate, and each lower projecting tab being formed by a portion of the second plate, inward of one of the side edges of the second plate, projecting outwardly beyond the side edge of the first plate; wherein, with the heat exchanger elements arranged side-by-side in the array, an adjacent pair of the heat exchanger elements is arranged with the upper projecting tab of a first heat exchanger element overlapping the lower projecting tab of an adjacent second heat exchanger element; and wherein each pair of upper and lower projecting tabs in overlapping arrangement comprises the at least one stiffening element.

According to an aspect, the upper projecting tab of the first heat exchanger element is substantially co-planar with the upper projecting tab of the second heat exchanger element; and/or wherein the lower projecting tab of the first heat exchanger element is substantially co-planar with the lower projecting tab of the second heat exchanger element.

According to an aspect, the overlapping upper and lower projecting tabs of the first and second heat exchanger elements are secured together.

According to an aspect, the side edges of the second plates of adjacent heat exchanger elements are spaced apart from one another; wherein the first plates of the plurality of heat exchanger elements are integrally connected together to provide an integral first plate having an inner surface and an outer surface, wherein the second plates are sealingly joined to the inner surface of the integral first plate, and the integral first plate has an area which is greater than a combined area of the plurality of second plates; wherein the at least one stiffening element comprises a plurality of spaced apart ribs formed in the first plate, and located between the side edges of adjacent heat exchanger elements.

According to an aspect, the ribs are elongated parallel to an axis which is perpendicular to the side edges of the second plates; wherein the external manifold portion is provided along the outer surface of the integral first plate; and wherein the external manifold portion extends along the axis which is perpendicular to the side edges of the second plates.

According to an aspect, in each of the heat exchanger elements, the first plate has a pair of side edges and the first and second plates of each heat exchanger element are sealingly joined together; and wherein the external manifold portion comprises a flattened tubular structure enclosing both the inlet manifold channel and the outlet manifold channel, the external manifold portion extending across all the heat exchanger elements along an axis which is perpendicular to the side edges of the first and second plates; wherein the at least one stiffening element comprises a plurality of bends in the external manifold portion, wherein the bends creating first and second portions of the external manifold portion which are located in different planes and which are separated by inclined shoulders; wherein the first portions located in a first plane and the second portions located in a second plane, the first and second planes being substantially parallel and spaced apart by approximately a thickness of the heat exchanger elements.

According to an aspect, each of the first portions extends along an outer surface of one of the second plates, and each of the second portions is located in an aperture provided between an adjacent pair of heat exchanger elements.

According to an aspect, each of the inclined shoulders is formed by a pair of opposite bends proximate to the side edges of the first and second plates.

According to an aspect, each of the first portions of the external manifold portion is mechanically secured to one of the heat exchanger elements.

DETAILED DESCRIPTION

As an overview,FIGS. 1A, 1B, and 2(andFIGS. 10 and 11) show exemplary heat exchangers having a novel modular construction, which the present inventors discovered (in various embodiments illustrated and described herein) enables heat exchangers of different dimensions to be constructed from a small (or smaller) number of parts and/or with simplified manufacturing/construction techniques (as compared to existing designs).FIG. 2shows an exploded view of an exemplary heat exchanger comprising a substantially flat cover plate, a plurality of second plates (each preferably stamped to define a plurality of fluid flow passages), and an external manifold portion adapted to provide thermal regulating fluid (or heat transfer fluid) to each of the second plates and to receive the thermal regulating fluid discharged from each of the second plates, with the second plates sandwiched between the cover plate and the external manifold portion.FIG. 3shows an exemplary second plate in greater detail, illustrating, for example, novel U-shaped or counterflow fluid flow paths developed by the present inventors that provide improved heat transfer from/to a second plate material and/or a heat transfer surface attached thereto.FIGS. 4 and 5show in greater detail various aspects of an exemplary external manifold that the present inventors discovered (in various embodiments disclosed herein) enables a single external manifold structure to function as both an inlet manifold (to provide input fluid to a plurality of heat exchanger elements) and an outlet manifold (to receive output fluid from the plurality of heat exchanger elements).FIGS. 6, 7A, 7B, 8, 9A, and 9B(andFIGS. 12 and 13) show various embodiments pertaining to what may be referred to as jigsaw features (or cutouts and/or tabs and/or overlapping tabs) along correspondingly mating edges of adjacent second plates (with comparison to existing designs), which the present inventors discovered avoid weaknesses between adjacent second plates.FIGS. 14, 15A, 15B, and 15Cshow embodiments having cutouts along side edges (or side edges interrupted by cutouts) between adjacent second plates, andFIGS. 16 and 17show embodiments wherein stiffening ribs may be formed in the first (cover) plate that extend into cutout openings/gaps along correspondingly mating edges of adjacent second plates. Finally,FIGS. 18-21show embodiments wherein a heat exchanger comprises a plurality of modules, each having a cover plate and a second plate of substantially the same size/area, with an external manifold portion (having bends to increase rigidity and stiffness) interconnecting the modules together.

Referring now toFIGS. 1A to 5, there is shown a cold plate heat exchanger10according to a first embodiment. Heat exchanger10comprises a generally flat first plate12(also referred to herein as “cover plate”) having inner and outer surfaces14,16and a plurality of formed second plates18(also referred to herein as “base plates”), each having inner and outer surfaces20,22. The first plate12is shown as being transparent inFIG. 1A.

As illustrated inFIG. 2, the outer surface16of first plate12defines a generally flat surface upon which a plurality of battery cells and/or battery modules2(FIG. 2) are stacked or supported, and which therefore serves as the primary heat transfer surface of the heat exchanger10. In the illustrated embodiment, the outer surface16of first plate is completely flat and free of any fluid fittings, manifolds, etc., and therefore the entire surface area of outer surface is available for heat transfer with the battery cells and/or battery modules.

In preferred embodiments, heat exchanger10comprises a plurality of heat exchanger elements10′, each of which comprises the first plate12, and one of the second plates18. Therefore, in preferred embodiments, the first plates of the individual heat exchanger elements10′ are integrally connected together to provide integral first plate12to which all the second plates18are sealingly joined. Preferably, the integral first plate12has an area which is at least as great as the combined area of the second plates18.

As shown inFIG. 2, heat exchanger10includes five identical second plates18and an integral first plate12which connects the heat exchanger elements into a single unit in which the heat exchanger elements10′ are arranged as a substantially planar array. As will be appreciated, the first plate12(in some embodiments) is preferably completely flat and does not have any stamped features. Therefore, no specialized equipment such as large presses are required for forming the first plate12. The second plates18are of a size which permits them to be economically produced by conventional forming equipment. The second plates, for example, are preferably stamped to provide (and define or at least partially define) a plurality of fluid flow passages. Where the size of first plate12is too large to permit the heat exchanger10to be joined together by furnace brazing, the second plates18may be sealingly joined to the first plate12by laser welding.

As shown inFIG. 2, the first and second plates12,18are joined together with their inner surfaces14,20in opposed facing relation to one another, and with portions of the inner surfaces14,20being spaced apart from one another. For example, in one embodiment, each second plate18has a central, generally planar base24surrounded by a raised peripheral side wall26extending from the base24to a planar peripheral flange28defining a planar peripheral sealing surface30on the inner surface20of second plate18.

Preferably, each heat exchanger element further comprises at least one fluid flow passage34for flow of a heat transfer fluid, the at least one fluid flow passage34being located between the spaced apart portions of the inner surfaces14,20of the first and second plates12,18. In this regard, the planar base24of second plate18is provided with a plurality of spaced apart ribs70which define (in combination with inner surface14of first plate12) the at least one fluid flow passage34. The ribs70extend upwardly out of the plane of the planar base24and have a sufficient height such that the flat or rounded top surface of each rib70defines a sealing surface which is substantially co-planar with the sealing surface30of planar flange28. During assembly of heat exchanger10, the sealing surface30of planar flange28and the sealing surfaces of the ribs70are sealingly joined to the inner surface14of first plate12, such that the inner surface14of first plate12defines the top wall of the at least one fluid flow passage34, the planar base24of second plate18defines the bottom wall of the at least one fluid flow passage34, and the ribs70and peripheral side wall26together define the sides of the at least one fluid flow passage34.

As shown inFIG. 3, the second plates18each have a length (along y-axis) and a width (along x-axis), and are shown as being elongate in the length dimension. The ribs70are also elongated along the length dimension of the second plate18, and the pattern of ribs70is configured to provide each heat exchanger element with a plurality of fluid flow passages34defining a “counterflow” flow pattern, in which a plurality of cold channels and a plurality of hot channels are arranged in an alternating orientation across the width (along x-axis) of the second plate18.

The ribs70of each second plate18are preferably configured as elongated U-shapes, having a pair of elongated legs72,74(along y-axis) joined by a transverse rib portion76. The ribs70are arranged in two groups78,80which are spaced apart from one another along the length dimension of the second plate18, with the ribs70of each group78,80being spaced apart across the width dimension of the second plate. The closed ends of the U-shaped ribs70are located proximate to the middle of second plate18, while the open ends of ribs70are located proximate to the (lengthwise) ends of the second plate18, spaced from the sidewall26and flange28.

The fluid flow passages34each have an open first end36defined as a space between a pair of adjacent U-shaped ribs70(or between a U-shaped rib70and the sidewall26/flange28), and a second end38located between the legs72,74of one of the ribs70, proximate to the transverse rib portion76. Each fluid flow passage34therefore has a generally U-shaped configuration, with the flow changing direction in a turnaround area82defined between the open ends of the U-shaped ribs70and the sidewall26/flange28at the opposite ends of second plate18.

Each second plate18further preferably comprises at least one first inlet port40and at least one first outlet port42. In one embodiment, the at least one first inlet port40comprises a continuous, transversely extending slot (along x-axis) through the second plate18, which is located proximate to the middle of second plate18, between the first and second groups78,80of ribs70. The central area of second plate18between the two groups78,80of ribs70therefore provides an internal manifold area84within which fluid from the at least one first inlet port40is distributed across the width of the second plate18and supplied to the open first ends36of the fluid flow passages34.

In one embodiment, the at least one first outlet port42comprises a plurality of apertures through the second plate18, each of which is provided at or proximate to the second end38of a fluid flow passage34, i.e. between the legs72,74of one of the ribs70, proximate to the transverse rib portion76.

Therefore, with this arrangement, it can be seen that each fluid flow passage includes a cold channel (receiving cold fluid from first inlet port40) and a hot channel (discharging hot fluid to the first outlet port42), with the hot and cold channels being arranged in alternating order across the width of the second plate18. It will be appreciated that the flow of heat transfer fluid can be reversed so that the first inlet port40becomes the outlet port, and the first outlet port42becomes the inlet. Furthermore, although each fluid flow passage34is defined as a U-shaped passage which changes direction in turnaround area82, it will be appreciated that there will necessarily be some mixing of flow and transverse flow distribution between fluid flow passages34in the turnaround area82, since the fluid flow passages34are not separated from one another in area82.

As shown inFIG. 4(and inFIG. 1B), heat exchanger10further comprises an external manifold portion44which, in one embodiment, extends transversely across the heat exchanger10and the second plates18(along x-axis). The external manifold portion44comprises a second inlet port46through which the heat transfer fluid is supplied to heat exchanger10through the external manifold portion44, and a second outlet port48through which the heat transfer fluid is discharged from the heat exchanger10through the external manifold portion44. The second inlet and outlet ports46,48may be provided with tubular fluid fittings (such as tubular fluid fitting50,52shown inFIG. 20) to permit the second inlet and outlet ports46,48to be connected to the battery heating/cooling system of the vehicle (not shown).

The external manifold portion44further comprises an inlet manifold channel54in fluid communication with the at least one first inlet port40of each heat exchanger element and with the second inlet port46, and an outlet manifold channel56in fluid communication with the at least one first outlet port42of each heat exchanger element and with the second outlet port48. Therefore, the external manifold portion44distributes and supplies the heat transfer fluid to each of the heat exchanger elements40through the second plate18thereof. The external manifold portion44also receives the heat transfer fluid from each heat exchanger element through the second plate18thereof, in order to collect and discharge the heat transfer fluid from the heat exchanger elements.

As shown inFIG. 4, in one embodiment the external manifold portion44is formed separately from the first and second plates12,18, and is comprised of three plates sealingly joined together, and sealingly joined to the outer surfaces22(FIG. 3) of the second plates18, for example by mechanical sealing or by metallurgical bonding such as brazing or welding. The three plates are identified herein as the inner plate58, middle plate60and outer plate62.

The inner plate58is preferably flat and provided with a plurality of inlet apertures64and outlet apertures66, which are shaped, sized and arranged on inner plate58so as to align with the first inlet and outlet ports40,42of the plurality of second plates18.

The middle plate60preferably comprises a dished plate is provided with embossments in the form of elongate ribs which partly define the inlet and outlet manifold channels54,56. In this regard, a central embossment86is aligned with the central row of inlet apertures64of inner plate58, and has an open end88to permit the heat transfer fluid to enter the space enclosed by embossment86and inner plate58. The middle plate60also includes a pair of outer embossments90, each of which is aligned with one of the two rows of outlet apertures66of the inner plate58. The outer embossments90are joined at one end, with the middle plate60being provided with an aperture92through which the heat transfer fluid is discharged from the pair of outer embossments90. The areas enclosed between the outer embossments90(including the portion in which aperture92is formed) and the inner plate58define the outlet manifold channel56. It can be seen that the spaces between the inner and outer embossments86,90form part of the inlet manifold channel54.

The outer plate62is preferably in the form of a dished plate which nests with the middle plate60, and is provided with a pair of openings, namely an outlet aperture94which aligns with the outlet aperture92in middle plate60and is open to the outlet manifold channel56, and an inlet aperture96which is open to the inlet manifold channel54. The inlet aperture96defines the second inlet port46of the external manifold portion44, and the aligned outlet apertures92,94define the second outlet port48of the external manifold portion44. In one embodiment the second inlet and outlet ports46,48are located proximate to one end of the external manifold portion44, although it will be appreciated that the locations of the ports46,48can be varied.

In one embodiment, heat transfer fluid is able to flow through inlet aperture96and second inlet port46(of the external manifold portion44), through inlet manifold channel54(along the x-axis/transverse direction), and into open end88and the x-axis/transverse channel within central embossment86. From central embossment86(of the external manifold portion44), fluid is able to flow through inlet aperture64and into the second plate18via first inlet port40. From inlet port40, fluid is able to flow (primarily) in a lengthwise (y-axis) direction toward the ends of the second plate18via fluid flow passage34. Fluid may then turn around at the open ends of ribs70to thereafter flow back toward the middle of the second plate18and though first outlet port42. From first outlet port42(of the second plate18) fluid is able to flow into outlet aperture66(of the external manifold portion44) and through (x-axis/transverse running) outlet manifold channel56. From outlet manifold channel56fluid is able to flow out of the external manifold via discharge outlet aperture92and outlet aperture94.

In preferred embodiments, the heat exchanger10further comprises at least one stiffening element arranged between adjacent heat exchanger elements in the array, in order to limit deflection between the adjacent heat exchanger elements. The at least one stiffening element of heat exchanger10is now explained below with reference toFIGS. 6 to 8.

As mentioned above, the second plate18of each heat exchanger element includes a planar peripheral flange28surrounding the at least one fluid flow passage34, and flange28defines a planar peripheral sealing surface30along which the inner surface20of the second plate18is sealingly joined to the inner surface14of the first plate12. As shown inFIGS. 3 and 6, each second plate18has first and second side edges98,100defining the longer sides of the second plate18and extending along the y-axis. Each second plate18also has first and second end edges (extending between first side edge98and second side edge100) defining the shorter sides of the second plate18and extending along the x-axis. In the array of heat exchanger elements making up heat exchanger10, the side edges98,100of all the second plates18are at least generally parallel to one another, and the end edges of all the second plates18are at least generally parallel to one another.

The planar flange28includes relatively wide side portions (width of side portions measured along x-axis) which extend along the side edges98,100, and also includes relatively narrow end portions (width of end portions measured along y-axis) which extend along the end edges102,104. The reason for the wider side portions of planar flange28will become apparent from the description below, although it will be appreciated that the width of the planar flange28at various areas around the periphery of the second plate18can be varied from that shown in the drawings.

Referring more specifically to the side edges98,100of the second plates18, it can be seen that the width of the planar flange28along the side edges98,100of second plate18(as measured along the x-axis) varies along the length of the side edges98,100(as measured along the y-axis).

As shown inFIG. 6, each of the side portions of the peripheral flange28extending along the side edges98,100of each second plate18includes at least one outermost edge portion106, each of the outermost edge portions106extending along at least a portion of the side edge98or100. A first axis A is defined along the at least one outermost edge portion108. In one embodiment, there is a plurality of outermost edge portions106along each of the side edges98,100, the plurality of outermost edge portions106being spaced apart from one another along the length of the side edge98or100. The outermost edge portions106in one embodiment correspond to the widest areas (or tabs) in the side portions of the peripheral flange28.

Also as shown inFIG. 6, each of the side portions of the peripheral flange28extending along the side edges98,100of each second plate18also includes at least one innermost edge portion108, each of the innermost edge portions108extending along at least a portion of the side edge98or100. A second axis B is defined along the at least one innermost edge portion108. In one embodiment, there is a plurality of innermost edge portions108along each of the side edges98,100, the plurality of innermost edge portions108being spaced apart from one another along the length of the side edge98or100. The innermost edge portions106in one embodiment correspond to the narrowest areas (or cutouts, or knotches, each of which is adjacent to a wider area/tab) in the side portions of the peripheral flange. The first and second axes A, B are parallel to one another and to axis-y.

As shown inFIG. 6, the second plates18,18′,18″ of the heat exchanger elements are each in side-by-side arrangement along the x-axis, wherein each of the second plates18,18′,18″ has at least one of its side edges98,100positioned with its first axis A, A′, A″ located between the first and second axes of an adjacent one of the second plates. For example, the first axis A of second plate18is positioned between the first axis A′ and the second axis B′ of an adjacent second plate18′. Similarly, the first axis A′ of the second plate18′ is positioned between the first axis A″ and second axis B″ of an adjacent second plate18″.

In the arrangement shown inFIG. 6, the outermost side edges106and innermost side edges108alternate with one another along each of the side edges98,100. In each adjacent pair of second plates18, the outermost edge portions106and innermost edge portions108of the adjacent second plates18have a complementary arrangement and shape. In this regard, each of the outermost edge portions106defines a male portion of the peripheral flange28and each of the innermost edge portions108defines a female portion of peripheral flange28. The male portions defined by outermost edge portions106are arranged in opposed relation to the female portions defined by the innermost edge portions108, and are shaped so as to be received in the female portions. In this way, the side edges98,100of adjacent second plates18do not overlap one another, but rather are interengaged, interlaced, or fit together in jigsaw puzzle fashion, to define a non-linear joint line110between the side edges98,100of adjacent second plates. Due to manufacturing tolerances, there will typically be a small gap112at the joint line110, and this gap112is similarly non-linear, since it follows the profile of the alternating innermost and outermost portions108,106of side edges98,100. The shapes of joint line110and gap112depend on the shapes of the innermost and outermost edge portions108,106, and may be described as meandering, tortuous, zig-zag or jagged.

In one embodiment, the plurality of stiffening elements are defined by the plurality of interlaced innermost and outermost edge portions108,106, which provide the non-linear joint line110and gap112, and these stiffening elements increase rigidity between adjacent heat exchanger elements by eliminating a linear bending axis (or bend line) along/between the side edges98,100of adjacent second plates18. In addition, the provision of the non-linear joint line110and gap112may provide a more uniform joint between adjacent second plates18, leading to more uniform deflection during internal pressure cycles and external loading.

The arrangement of is can be contrasted with prior artFIGS. 7A and 7B, showing side edges98,100of a pair of adjacent second plates18,18′ of a prior art heat exchanger as described in US 2016/0204486 A1. Similar reference numerals are used. As shown inFIGS. 7A and 7B, the two second plates18are sealingly joined to a first plate12. In prior art heat exchanger, the side edges98,100are straight and parallel to each other, and define a straight joint line110and a straight gap112between the first side edge98of one second plate18and the second side edge100of an adjacent second plate18. In the gap112, the heat exchanger is only one layer thick, i.e. being the thickness of first plate12. The linear joint line110and gap112define a linear bending axis along which there can be deflection of the adjacent heat exchanger elements, for example during shipping, handling, installation and/or use of the heat exchanger.

Referring back toFIG. 6, the innermost and outermost edge portions108,106of heat exchanger10are (as shown) rectangular, and provide each of the side edges98,100with a series of rectangular castellations. However, it will be appreciated that other arrangements are possible. For example, as shown inFIG. 8, the side edges98,100may have a more rounded arrangement so as to provide a joint line110and gap112which have a smoothly curved, meandering shape. InFIG. 8, adjacent second plates18,18′ have side edges98,100having wider (tab) areas108and narrower (cut) areas106, which are rounded and not rectangular as inFIG. 6.

The heat exchanger elements inFIG. 6are arranged side-by-side, and not end-to-end. In other embodiments, the array may include heat exchanger elements arranged side-by-side, end-to-end, and/or end-to-side. Two such embodiments are shown inFIGS. 9A and 9B.FIG. 9Ashows a portion of a heat exchanger10A in which there is a convergence of three second plates18in side-by-side and side-to-end arrangements.FIG. 9Bshows a portion of a heat exchanger10B in which there is a convergence of four second plates18in side-by-side and end-to-end arrangements. In these types of arrays, both the side edges98,100and the end edges102,104of the second plates18may be provided with innermost and outermost edge portions.

FIGS. 10-11show a heat exchanger120according to an alternate embodiment which shares a number of like elements with heat exchanger10as inFIG. 1. These like elements are described with like reference numerals and the following discussion will focus on differences between heat exchangers10(FIG. 1) and120(FIG. 10).

As shown inFIG. 10, heat exchanger120comprises a first plate12and a pair of second plates18, forming two heat exchanger elements10′. Each second plate18has only one side edge98or100provided with innermost (cut) and outermost (tab) edge portions106,108as described above (for similarly oriented cuts/cutouts and tabs), to provide a non-linear joint line110and gap112between the two second plates18. Because each second plate18has only one side edge98or100along which it is adjacent to another second plate18, the innermost and outermost edge portions106,108are provided along only one side edge98or100of each second plate18.

The second plates18include a pattern of ribs70which are configured to provide each heat exchanger element with a plurality of fluid flow passages34defining a “U-flow” flow pattern. The ribs70are linear and parallel, and are arranged in two groups78,80which are spaced apart from one another along the length dimension of the second plate18. The central rib70in each group78,80is labeled70A inFIG. 11, having a first end, near the middle of second plate18, which is joined to a flow blocking embossment122, and an opposite second end which terminates in turnaround area82, and is spaced from the sidewall26and planar flange28at one of the ends of the second plate18.

The flow blocking embossment122separates an inlet manifold area124from an outlet manifold area126, and the central ribs70A separate an inlet portion128and an outlet portion130of the second plate18. The remaining ribs70have first ends which terminate in either the inlet manifold area124or the outlet manifold area126, and second ends which terminate in the turnaround area82. The ribs70separate the inlet and outlet portions128,130into individual fluid flow passages34.

To provide structural support, the inlet and outlet manifold areas124,126and the turnaround areas82may be provided with additional spaced-apart embossments such as dimples132.

In heat exchanger120the external manifold portion44shown inFIG. 10is in the form of a flat tube closed along its sides and ends, and sealingly joined to the outer surface16of the first plate12and extending across the first plate12, along the x-axis. The external manifold portion44includes inlet and outlet openings46,48provided with inlet and outlet fittings50,52. The surface of manifold portion44which is in engagement with the outer surface16of first plate12includes inlet and outlet apertures64,66which are aligned and in communication with fluid inlet and outlet openings134,136of first plate12(FIG. 10). The inlet openings134of first plate12provide fluid communication between the inlet manifold area124and an inlet manifold channel54of the external manifold portion44, and outlet openings136provide fluid communication between the outlet manifold area126and an outlet manifold channel56of the external manifold portion44. The inlet and outlet manifold portions54,56of external manifold portion44are in flow communication with the respective inlet and outlet ports40,42, and are separated from one another by a dividing rib68extending along the x-axis. It can be seen that the inlet and outlet apertures64,66of external manifold portion44are arranged on opposite sides of the dividing rib68, and the fluid inlet and outlet openings134,136are staggered along the y-axis so as to align with the inlet and outlet apertures64,66of external manifold portion44. Instead of comprising a single flat tube with an internal dividing rib68, it will be appreciated that the external manifold portion44may comprise two separate flat tube structures enclosing the respective inlet and outlet manifold portions54,46.

FIGS. 12-13illustrate portions of a heat exchanger140according to an alternate embodiment. Heat exchanger140shares a number of like elements with heat exchangers10and/or120. These like elements are described with like reference numerals.

Heat exchanger140comprises a plurality of heat exchanger elements140′, each comprising a first plate12and a second plate18. In heat exchanger140, the first plates12of the plurality of heat exchanger elements140′ are separately formed, such that both the first plate12and the second plate18of each heat exchanger element140′ have at least approximately the same area, the first plate12of each heat exchanger element140′ including a pair of side edges142,144. With the heat exchanger elements140′ arranged side-by-side, at least one side edge142or144of the first plate12of one heat exchanger element140′ is in opposed facing relation, and substantially co-planar with, a side edge142or144of an adjacent heat exchanger element140′.

As described above with reference to heat exchanger10and120, each of the second plates18of the heat exchanger elements140′ is provided with a plurality of alternating innermost and outermost edge portions106,108along at least one of its side edges98,100. According to one embodiment, the first plates12of the heat exchanger elements140′ are similarly provided with a plurality of alternating innermost and outermost edge portions106′,108′ along at least one of its side edges142,144.

At least one of the side edges98,100,142,144of the first and second plates12,18in each heat exchanger element140′ are configured such that each of the innermost edge portions106′ of the first plate12overlies (overlaps) one of the outermost portions108of the second plate18, and each of the outermost portions108′ of the first plate12overlies (overlaps) one of the innermost portions106of the second plate18. It can be seen fromFIG. 12that upper and lower rows of projecting tabs are thus formed along the side edges98,100,142,144of the first and second plates12,18, wherein at least one side of each heat exchanger element140′ is formed in this fashion. Each of the projecting tabs of the upper row comprises an outermost portion108′ of one of the first plates12, and each of the projecting tabs of the lower row comprises an outermost portion108of one of the second plates18.

With the heat exchanger elements140′ arranged in a side-by-side array, as in heat exchangers10and120, each adjacent pair of heat exchanger elements140′ is arranged with the upper row of projecting tabs of one of the heat exchanger elements140′ overlapping the lower row of projecting tabs of the other heat exchanger element140′, and vice versa. In this way, the side edges98,100,142,144the first and second plates12,18of adjacent heat exchanger elements140′ are interengaged, interlaced, or fit together in jigsaw puzzle fashion, to define non-linear joint lines110between the side edges98,100of adjacent second plates18, and similar non-linear joint lines110′ between the side edges142,144of adjacent first plates12. Furthermore, the overlapping projecting tabs provided by the outermost edge portions108′,108of the first and second plates12,18provide an interlocking connection between the side edges98,100,142,144, and provide surfaces along which the side edges98,100,142,144may be secured together, for example by welding or by mechanical fastening, either with fasteners such as rivets, or without fasteners, for example by press-joining.FIG. 13shows weld joints146through the overlapping outermost edge portions108′,108.

FIGS. 14-15Cillustrate a heat exchanger150according to an alternate embodiment. Heat exchanger150shares a number of like elements with heat exchangers10,120and/or140. These like elements are described with like reference numerals.

Heat exchanger150comprises a plurality of heat exchanger elements150′, each comprising a first plate12and a second plate18. In heat exchanger150, the first plates12of the plurality of heat exchanger elements150′ are separately formed, such that both the first plate12and the second plate18of each heat exchanger element150′ have at least approximately the same area, the first plate12of each heat exchanger element150′ including a pair of side edges152,154. With the heat exchanger elements150′ arranged side-by-side, at least one side edge152or154of the first plate12of one heat exchanger element150′ is in opposed facing relation, and substantially co-planar with, a side edge152or154of an adjacent heat exchanger element150′. Heat exchanger150further comprises an external manifold portion44which extends transversely across the heat exchanger150and specifically across the outer surfaces16of the first plates12(along x-axis), and is similar or identical in structure to external manifold portion44of heat exchanger120described above.

The external manifold portion44of heat exchanger150comprises a flat tube closed along its sides and ends, and sealingly joined to the outer surface16of the first plate12and extending across the first plate12, along the x-axis. The external manifold portion44includes inlet and outlet openings46,48(not shown) provided with inlet and outlet fittings50,52. Although not shown, the surface of manifold portion44which is in engagement with the outer surface16of first plate12includes inlet and outlet apertures64,66on opposite sides of a dividing rib (such as diving rib68shown inFIG. 10), the apertures64,66being aligned and in communication with respective fluid inlet and outlet openings134,136of first plate12, as in heat exchanger120.

An upper projecting tab156or a lower projecting tab158is defined along at least one side of each heat exchanger element150′. Each upper projecting tab156comprises a portion of the first plate12, located inwardly of one of the side edges152or154, and projecting outwardly beyond the side edge98or100of the second plate18. Conversely, each lower projecting tab158comprises a portion of the second plate18, located inwardly of one of the side edges98,100, and projecting outwardly beyond the side edge152or154of the first plate12.

With the heat exchanger elements150′ arranged in a side-by-side array, as in heat exchangers10,120and140, each adjacent pair of heat exchanger elements150′ is arranged with the upper projecting tab156of one of the heat exchanger elements150′ overlapping the lower projecting tab158of the other heat exchanger element150′. In this way, the overlapping side edges98,100,152,154the first and second plates12,18of adjacent heat exchanger elements150′ are overlapped to provide a lap joint between adjacent heat exchanger elements150′ and provide surfaces along which the side edges98,100,152,154may be secured together, for example by welding or by mechanical fastening, either with fasteners such as rivets, or without fasteners, for example by press-joining.FIG. 15Ashows weld joints160through the overlapping upper and lower tabs156,158.

It will be appreciated that the upper and lower tabs156,158may either extend continuously along the side edges98,100,152,154, or they may be discontinues, for example being interrupted by cutouts162as shown inFIGS. 14, 15A and 15B(and cutout62inFIG. 15C).

Each of the heat exchanger elements140′,150′ of heat exchangers140and150may be similar or identical in size and shape to conventional brazed cold plate heat exchangers, thereby allowing the heat exchanger elements140′,150′ to be manufactured in a conventional manner, using conventional shaping equipment and furnace brazing. The heat exchanger elements140′,150′ can then be secured together side-by-side in the manner described above to form heat exchangers140,150having a plurality of heat exchanger elements140′,150′, and provided with external manifold portions as described herein. Similar end-to-end joining of heat exchanger elements140′,150′ can be accomplished by providing the end edges of first and second plates12,18with similarly formed projecting tabs as described above with reference to side edges98,100,142,144,152,154.

FIGS. 16-17illustrate a heat exchanger170according to an alternate embodiment. Heat exchanger170shares a number of like elements with heat exchangers10,120,140and/or150. These like elements are described with like reference numerals.

Heat exchanger170comprises a plurality of heat exchanger elements170′, each comprising a first plate12and a second plate18. As in heat exchangers10and120, heat exchanger170includes a single, integral first plate12to which a plurality of second plates18are sealingly joined in side-by-side arrangement. The second plates18of heat exchanger170are generally similar to the second plates18of heat exchanger120described above, each second plate18having side edges98,100, and having a pattern of ribs70which are configured to provide each heat exchanger element170′ with a plurality of fluid flow passages34defining a “U-flow” flow pattern. The ribs70are linear and parallel, and are arranged in two groups78,80which are spaced apart from one another along the length dimension of the second plate18. The central rib70in each group78,80is labeled70A, having a first end, near the middle of second plate18, which is joined to a flow blocking embossment122.

In heat exchangers10and120, the spacing between the side edges98,100of adjacent second plates18is minimized. In contrast, the side edges98,100of second plates18of heat exchanger170are intentionally spaced apart across the inner surface14of first plate12, along the x-axis. In the spaces along the sides of second plates18and between adjacent second plates18there are provided stiffening elements in the form of stiffening ribs172. In particular, there is a plurality of such stiffening ribs172between each adjacent pair of second plates18, wherein the stiffening ribs172between each pair of second plates18are spaced apart and arranged in a row along the y-axis.

The stiffening ribs172are formed as embossments in the first plate12, and at least some of the ribs172may be elongated parallel to an axis (the x-axis) which is perpendicular to the side edges98,100of the second plates18. Alternatively, at least some of the ribs172may be circular or any other convenient shape. In one embodiment, the outer surfaces22of second plates18form the surfaces on which the battery cells and/or modules are supported, and the embossments comprising stiffening ribs172are formed so as to protrude from the outer surface16of the first plate12, i.e. away from the surfaces on which the battery cells and/or modules are supported.

In addition to being embossed with stiffening ribs172, the first plate12of heat exchanger170differs from the flat first plates12of heat exchangers10and120in other important respects. In this regard, the first plate12is formed of two plate layers, including an inner plate layer174(FIG. 16) defining the inner surface14of first plate12, and an outer plate layer176(FIG. 17) defining the outer surface16of first plate12. Also, the external manifold portion44is integrated with the first plate12, with the outer plate layer176including a pair of elongate embossments178,180, wherein the inlet and outlet manifold channels54,56are formed between the inner plate layer174and the embossments178,180of the outer plate layer176, and with the inlet and outlet ports40,42being provided through the first plate12as shown inFIG. 16. The inlet and outlet ports40,42may be provided with fittings (not shown), which may extend from the inner surface14of first plate12. Although not visible in the drawings, the inner plate layer174has inlet and outlet manifold openings in communication with the fluid flow passages34defined between the first plate12and the second plates18. The embossments178,180and the external manifold portion44of heat exchanger170extend along the x-axis, i.e. the axis which is perpendicular to the side edges98,100of the second plates18, and therefore also serve to enhance the stiffness of the heat exchanger170along the x-axis.

The heat exchanger170according to one embodiment may be constructed by welding together inner and outer plate layers174,176to provide the first plate12and external manifold portion, and by welding together the second plates18and the first plate12. Instead of having two layers174,176with an integrally formed external manifold portion44, it will be appreciated that the first plate12may comprise a single layer, and the external manifold portion44may be formed separately from first plate12, as in the embodiments described above. Also, instead of comprising two separate embossments178,180, the external manifold portion44may comprise a single flat tube with an internal dividing rib, as in the external manifold portions44of heat exchangers120and150described above.

FIGS. 18-21illustrate a heat exchanger190according to an alternate embodiment. Heat exchanger190shares a number of like elements with heat exchangers10,120,140,150and/or170. These like elements are described with like reference numerals.

Heat exchanger190is similar to heat exchangers140and150in that it comprises a plurality of heat exchanger elements190′, each comprising a first plate12and a second plate18. In heat exchanger190, the first plates12of the plurality of heat exchanger elements190′ are separately formed, such that both the first plate12and the second plate18of each heat exchanger element190′ have at least approximately the same area, the first plate12of each heat exchanger element190′ including a pair of side edges192,194. With the heat exchanger elements190′ arranged side-by-side, at least one side edge192or194of the first plate12of one heat exchanger element190′ is in opposed facing relation, and substantially co-planar with, a side edge192or194of an adjacent heat exchanger element190′.

The first plates12of heat exchanger190are flat and the outer surfaces16of the first plates12define the surfaces on which the battery cells and/or modules are supported. The second plates18are similar to those of heat exchanger170described above, each second plate18having side edges98,100, and having a pattern of ribs70which are configured to provide each heat exchanger element190′ with a plurality of fluid flow passages34defining a “U-flow” flow pattern. The rib structure of heat exchanger elements190′ is relatively simple, however, in that only includes two central ribs70, each having a first end, near the middle of second plate18, which is joined to a flow blocking embossment122.

Heat exchanger190differs from heat exchangers140,150in that the at least one stiffening element between adjacent heat exchanger elements190′ in the side-by-side array do not necessarily include any connections between adjacent heat exchanger elements190′, in the manner of heater exchangers140,150discussed above. Rather, in heat exchanger190, the at least one stiffening element between adjacent heat exchanger elements190′ is provided by the external manifold portion44, as described below.

In this regard, the external manifold portion44comprises a flattened tubular structure enclosing both the inlet manifold channel54and the outlet manifold channel56, separated by an internal dividing rib (such as dividing rib/internal barrier208). The external manifold portion44extends across all the heat exchanger elements190′ along an axis (the x-axis) which is perpendicular to the side edges192,194of the first plate12and the side edges98,100of the second plate18.

The at least one stiffening element of heat exchanger190comprises a plurality of bends in the external manifold portion44, wherein the bends are arranged to separate a plurality of first and second portions of the external manifold portion44. For example, in the illustrated embodiments, the external manifold portion44includes a plurality of first portions196, each of which is flat and planar, and extends along the outer surface16of the first plate12of one of the heat exchanger elements190′. The first portions196are all substantially co-planar with one another.

The external manifold portion44also includes a plurality of second portions198which are substantially co-planar with one another, the plane of the first portions196being substantially parallel to and spaced from the plane of the second portion198by an amount which is about the same as the thickness of the heat exchanger element190′. In the illustrated embodiment, the second portions198may be substantially co-planar with the outer surfaces of the second plates18.

As best seen inFIGS. 20 and 21, the first and second portions196,198are separated by inclined shoulders200, each of which is formed by a pair of opposite bends202,204(FIG. 21) proximate to the side edges98,100,192,194of the first and second plates12,18.

The side edges98,100,192,194have inwardly extending portions205near the middle of each heat exchanger element190′, such that apertures206(FIG. 19) are provided between the middle portions of adjacent heat exchanger elements190′. The second portions198of the external manifold portion44are received in these apertures206.

As shown inFIG. 20, the inlet and outlet manifold channels54,56of external manifold portion44may be separated by an internal barrier208, and the inlet and outlet apertures64,66of the external manifold portion44are formed on either side of the internal barrier208, in communication with inlet and outlet ports formed through the first plate12(not shown). To enable mechanical connection of the external manifold portion44to the heat exchanger elements190′, resilient sealing elements such as O-rings210are provided between the inlet and outlet apertures64,66of the external manifold portion44and the inlet and outlet ports of the first plate12. Also, fastener holes212,214are provided through the respective external manifold portion44and the heat exchanger elements190′. The holes212,214are adapted to receive fasteners (not shown) such as screws or bolts, for fastening the manifold portion44and heat exchanger elements190′ together, and optionally for fastening the heat exchanger190to a support structure (not shown).

The fastener holes212of the external manifold portion44may extend through the second portions198, for example through the internal barrier208and proximate to the inlet and outlet apertures64,66. The fastener holes214of the heat exchanger elements190′ may extend through the first plate12and through the flow-blocking embossment122in the second plate18.

The external manifold portion44is also provided with first and second tubular fittings50,52for connection to the battery heating/cooling system of the vehicle (not shown).

It will be appreciated that each of the heat exchangers described herein may optionally be provided with one or more electric heating element (such as, for example, an electric heating element) for heating the heat transfer fluid (or thermal regulating fluid) flowing through the heat exchanger, and/or with one or more chiller (or cooling element) (such as, for example, an electric cooling element) for cooling the heat transfer fluid flowing through the heat exchanger.

As used herein, the terms “approximately” is construed to mean plus or minus five percent of the range unless otherwise specified.

While various embodiments have been described in connection with the present disclosure, it will be understood that certain adaptations and modifications of the described exemplary embodiments can be made as construed within the scope of the present disclosure. Therefore, the above discussed embodiments are considered to be illustrative and not restrictive.