Tubular element for a heat exchanger

Abstract

A tubular element for a heat exchanger, including: a primary tank with an inlet and outlet chambers, a secondary tank, a tube extending between the primary and secondary tanks, configured so as to provide U-flow for a fluid. The tube includes first and second separation walls with a separation space there-between. A dividing wall of the primary tank is in contact with the first and second separation walls. The inlet channels include a first inlet channel limited by the first separation wall and an inlet channel wall. The outlet channels include a first outlet channel limited by the second separation wall and an outlet channel wall. A distance between the first and second separation walls is smaller than a distance between the first separation wall and the inlet channel wall and is smaller than a distance between the second separation wall and the outlet channel wall.

Description

TECHNICAL FIELD

[0001] The present invention pertains to a tubular element designed for use in a heat exchanger, particularly for regulating the temperature of an electric device, such as a battery in a vehicular system.BACKGROUND OF THE INVENTION

[0002] A critical component of electric vehicle technology is the battery pack, which serves as the primary energy storage system. Among various battery formats, cylindrical, e.g. lithium-ion, cells are widely used due to their high energy density, structural stability, and efficient packing configuration.

[0003] Thermal management of these battery packs is essential to ensure optimal performance, safety, and longevity. During operation, battery cells generate significant heat, particularly during high discharge rates or rapid charging. Conversely, in cold conditions, batteries may require heating or conditioning to maintain efficient and prevent capacity loss due to low temperatures.

[0004] Effective cooling is required to prevent overheating, which can lead to reduced efficiency, accelerated degradation, or even thermal runway in extreme cases, while active heating systems are necessary to ensure consistent performance in suboptimal thermal environments.

[0005] Heat exchangers are commonly employed in battery systems to manage temperature. These systems often rely on tubular elements to circulate a heat exchange fluid for heat dissipation. The design of these tubular elements is crucial to achieving uniform and efficient cooling across the densely packed cylindrical cells in a battery module.

[0006] Undulated tubes have emerged as an effective solution for improving heat transfer in such applications. The wavy geometry promotes turbulence in the heat exchange fluid flow, increasing the efficiency of heat exchange between the surface and the fluid. Additionally, wavy tubes are adaptable to the complex geometries of battery packs, ensuring consistent cooling across all cells and reducing the risk of localized hotspots.

[0007] There remains a need for a tubular element specifically optimized for use in heat exchangers for cylindrical battery packs in electric vehicles. Such a solution should address the dual objectives of enhancing heat dissipation and conforming to the compact and intricate design requirements of modern battery systems. This invention aims to fulfill these needs.SUMMARY OF THE INVENTION

[0008] An object of the invention is a tubular element for a heat exchanger, comprising: a primary tank with an inlet chamber and an outlet chamber for a heat exchange fluid, a secondary tank, a tube extending between the primary tank and the secondary tank, with a set of inlet channels and a set of outlet channels, configured so as to provide U-flow for the fluid within the tubular element, wherein the primary tank includes a dividing wall between the inlet chamber and the outlet chamber, wherein the tube includes a first separation wall and a second separation wall with a separation space between the first separation wall and the second separation wall, the first separation wall and the second separation wall being configured to block fluid flow between the set of inlet channels and the set of outlet channels within the tube, wherein the dividing wall is in contact with the first separation wall and the second separation wall, wherein the set of inlet channels includes a first inlet channel limited by the first separation wall and an inlet channel wall, and wherein the set of outlet channels includes a first outlet channel limited by the second separation wall and an outlet channel wall, wherein a distance between the first separation wall and the second separation wall is smaller than a distance between the first separation wall and the inlet channel wall and is smaller than a distance between the second separation wall and the outlet channel wall.

[0009] In one option, center portions of the first separation wall and the second separation wall are in contact.

[0010] In one option, the first separation wall and the second separation wall are in contact only in the vicinity of the primary tank.

[0011] In one option, the first separation wall and the second separation wall are mechanically pinched towards each other.

[0012] In one option, the first separation wall and the second separation wall are arcuate.

[0013] In one option, the first separation wall and the second separation wall are bent away from each other.

[0014] In one option, the tube includes a top wall and a bottom wall opposite the top wall, with the set of inlet channels and the set of outlet channels being arranged between the top wall and the bottom wall, wherein a distance between center portions of the first separation wall and the second separation wall is larger than respective distances at the top wall and the bottom wall.

[0015] In one option, the first separation wall and the second separation wall are bent away from each other along the whole length of the tube.

[0016] In one option, the first separation wall and the second separation wall are bent away from each other only in the vicinity of the primary tank.

[0017] In one option, the dividing wall 13, the first separation wall and the second separation wall are brazed to each other.

[0018] In one option, the first inlet channel includes an inlet flat section at the inlet channel wall, while the first outlet channel includes an outlet flat section at the outlet channel wall.

[0019] In one option, the tube includes a top wall and a bottom wall opposite the top wall, with the set of inlet channels and the set of outlet channels being arranged between the top wall and the bottom wall, wherein the first separation wall and the second separation wall extend between the top wall and the bottom wall.

[0020] In one option, the tube includes a top wall and a bottom wall opposite the top wall, with the set of inlet channels and the set of outlet channels being arranged between the top wall and the bottom wall, wherein the inlet channel wall and the outlet channel wall extend between the top wall and the bottom wall.

[0021] In one option, the set of inlet channels includes a plurality of second inlet channels of a rectangular shape in cross-section, arranged in series next to each other, while the set of outlet channels includes a plurality of second outlet channels of a rectangular shape in cross-section, arranged in series next to each other.

[0022] In one option, the tube extends along a meandering path between the primary tank and the secondary tank.

[0023] In one option, the primary tank is formed from two shaped portions connected to each other.

[0024] In one option, the two shaped portions are connected to each other by crimping tabs present on at least one of the two shaped portions.

[0025] In one option, each of the two shaped portions includes a dividing wall component extending towards the other of the two shaped portions so that the dividing wall components are connected to each other and together they form the dividing wall.

[0026] Another object of the invention is a tube for a tubular element of a heat exchanger, comprising: a set of inlet channels and a set of outlet channels, a first separation wall and a second separation wall with a separation space between the first separation wall and the second separation wall, the first separation wall and the second separation wall being configured to block fluid flow between the set of inlet channels and the set of outlet channels within the tube, wherein the set of inlet channels includes a first inlet channel limited by the first separation wall and an inlet channel wall, and wherein the set of outlet channels includes a first outlet channel limited by the second separation wall and an outlet channel wall, wherein the set of inlet channels includes a plurality of second inlet channels of a rectangular shape in cross-section, arranged in series next to each other, while the set of outlet channels includes a plurality of second outlet channels of a rectangular shape in cross-section, arranged in series next to each other, wherein a distance between the first separation wall and the second separation wall is smaller than a distance between the first separation wall and the inlet channel wall and is smaller than a distance between the second separation wall and the outlet channel wall, wherein the first inlet channel includes an inlet flat section at the inlet channel wall, while the first outlet channel includes an outlet flat section at the outlet channel wall, wherein the first inlet channel includes an inlet arcuate structure at the first separation wall, while the first outlet channel includes an outlet arcuate structure at the second separation wall.BRIEF DESCRIPTION OF DRAWINGS

[0027] The present invention will be described in greater detail below with reference to the drawings. In the drawings:

[0028] FIG. 1 shows a tubular element in a perspective view;

[0029] FIG. 2 shows the primary tank of the tubular element in a perspective view;

[0030] FIG. 3 shows the secondary tank of the tubular element in a perspective view;

[0031] FIG. 4 shows a partial perspective view of a primary tank with one of the shaped portions removed;

[0032] FIG. 5 shows a closer view of the primary tank of FIG. 4;

[0033] FIG. 6 shows schematically a view of an example of a tube of the tubular element;

[0034] FIG. 7 shows schematically a view of another example of a tube of the tubular element; and

[0035] FIG. 8 shows schematically a view of an example of a tube of the tubular element.DETAILED DESCRIPTION OF THE INVENTION

[0036] FIG. 1 shows a tubular element 1 for a heat exchanger in a perspective view, with FIG. 2 and FIG. 3 showing respectively a primary tank 10 and a secondary tank 20 of the tubular element 1 in closer views. The tubular element 1 comprises a primary tank 10 and a secondary tank 20. A tube 30 extends between the primary tank 10 and the secondary tank 20. The primary tank 10, the secondary tank 20 and the tube 30 are configured so as to provide U-flow for the fluid within the tubular element 1. The primary tank 10 can be a distribution tank. The secondary tank 20 can be a return tank. The tube 30 can be a flat, wavy tube, to maximize the surface area in contact with the battery cell. The U-flow arrangement refers to the coolant flow pattern where fluid enters the tube 30, travels in one direction to the end, and then reverses its path in the opposite direction within the same tube. This creates a “U”-shaped flow path within the flat tube, which is designed to optimize heat exchange performance and flow uniformity.

[0037] The primary tank 10 includes an inlet chamber 11 with an inlet connector 14, as well as an outlet chamber 12 with an outlet connector 15. The inlet chamber 11 is separated from the outlet chamber 12 within the primary tank 10. The heat exchange fluid enters the tube 30 and flows along the first leg of the U-path, absorbing heat from the battery cell through the flat surface or giving the heat away to the cell.

[0038] The secondary tank 20 ensures flow reversal, in a sense that the heat exchange fluid is redirected to flow back along the second leg of the U-path, further enhancing heat exchange. The heat exchange fluid exits the tube 30 after completing the U-path.

[0039] The tube 30 extends along a meandering path between the primary tank 10 and the secondary tank 20.

[0040] The tube 30 can be extruded. The tube 30 can be of aluminum.

[0041] The primary tank 10 can be formed from two shaped portions 16 connected to each other. The two shaped portions 16 can be connected to each other by crimping tabs 17 present on at least one of the two shaped portions 16.

[0042] FIG. 4 shows a partial perspective view of a primary tank with one of the shaped portions removed, while FIG. 5 shows a closer view of the primary tank of FIG. 4.

[0043] The tube 30 includes a set of inlet channels 31 and a set of outlet channels 32. The set of inlet channels 31 leads the fluid from the primary tank 10 to the secondary tank 20. The set of outlet channels 32 leads the fluid from the secondary tank 20 to the primary tank 10. In other words, both the set of inlet channels 31 and the set of outlet channels 32 terminate in the primary tank 10 and the secondary tank 20.

[0044] The primary tank 10 includes a dividing wall 13 between the inlet chamber 11 and the outlet chamber 12. The dividing wall 13 separates the fluid within the inlet chamber 11 from the fluid in the outlet chamber 12.

[0045] Each of the two shaped portions 16 can include a dividing wall component 13 extending towards the other of the two shaped portions 16 so that the dividing wall components 13 can be connected to each other and together they form the dividing wall 13.

[0046] The dividing wall 13 can be in contact with the first separation wall 33 and the second separation wall 34.

[0047] The tube 30 can include a first separation wall 33 and a second separation wall 34 with a separation space 35 between the first separation wall 33 and the second separation wall 34. The first separation wall 33 and the second separation wall 34 can be configured to block fluid flow between the set of inlet channels 31 and the set of outlet channels 32 within the tube 30.

[0048] In general, when brazing aluminum, the filler material travels along the elements primarily through capillary action, driven by precise heating and preparation. As the aluminum components are heated to the brazing temperature (typically between 570 degree Celsius and 620 degree Celsius), the brazing filler, often an aluminum-silicon alloy, melts at a lower temperature then the base material. The molten filler flows between the tightly fitted aluminum components, drawn by capillary action, while surface tension helps it distribute uniformly. As the assembly cools, the filler material solidifies, creating a strong, durable metallic bond. Proper joint preparation is essential for efficient and uniform brazing.

[0049] The set of inlet channels 31 can include a first inlet channel 311 limited by the first separation wall 33 and an inlet channel wall 312. The set of outlet channels 32 can include a first outlet channel 321 limited by the second separation wall 34 and an outlet channel wall 322. The inlet channel wall 311 and the outlet channel wall 322 are not in contact with the dividing wall 13.

[0050] The set of inlet channels 31 can include a plurality of second inlet channels 315 of a rectangular shape in cross-section, arranged in series next to each other. The set of outlet channels 32 can include a plurality of second outlet channels 325 of a rectangular shape in cross-section, arranged in series next to each other. In other words, channels of the sets 31, 32 feature a cross-sectional geometry that is substantially rectangular. The rectangular cross-sectional shape can be defined by parallel opposing walls interconnected by perpendicular side walls, forming a continuous enclosed pathway for the flow of fluid. This configuration ensures uniform dimensions along the length of each channel, promoting consistent fluid dynamics and heat transfer characteristics. The channels can be designed to be evenly spaced, maintaining a uniform interval between adjacent channels to optimize structural integrity and thermal performance within the system. The term “substantially rectangular” is used in a sense that inner corners of the channels will at some level be slightly rounded due to manufacturing constraints.

[0051] FIG. 6 shows schematically a view of an example of a tube 30 of the tubular element 1. The tube 30 includes a top wall 37 and a bottom wall 38 opposite the top wall 37. The set of inlet channels 31 and the set of outlet channels 32 can be arranged between the top wall 37 and the bottom wall 38.

[0052] The first separation wall 33 and the second separation wall 34 can extend between the top wall 37 and the bottom wall 38

[0053] The inlet channel wall 312 and the outlet channel wall 322 can extend between the top wall 37 and the bottom wall 38.

[0054] A distance between the first separation wall 33 and the second separation wall 34 is smaller than a distance between the first separation wall 33 and the inlet channel wall 312 and is smaller than a distance between the second separation wall 34 and the outlet channel wall 322. The distance can be measured along the top wall 37 and / or bottom wall 38. The distance can be measured perpendicularly to the general extension direction of the tube 30 between the primary tank 10 and the secondary tank 20. In other words, the channel formed by the first separation wall 33 and the second separation wall 34 is narrower than at least each of the neighboring channels for the fluid.

[0055] The first inlet channel 311 includes an inlet flat section 314 at the inlet channel wall 312, while the first outlet channel 321 includes an outlet flat section 324 at the outlet channel wall 322.

[0056] FIG. 7 shows schematically a view of another example of a tube 30 of the tubular element 1.

[0057] Center portions C of the first separation wall 33 and the second separation wall 34 can be in contact. For example, the center portions C can be located midway between the top wall 37 and the bottom wall 38. The rest of the first separation wall 33 and the second separation wall 34 are not in contact with each other, i.e. above and below the center portions C.

[0058] The first separation wall 33 and the second separation wall 34 can be in contact for example only in the vicinity of the primary tank 10. In other words, the rest of the first separation wall 33 and the second separation wall 34 can stay separated throughout the rest of the run of the tube 30 towards the secondary tank 20.

[0059] The first separation wall 33 and the second separation wall 34 can be mechanically pinched towards each other.

[0060] FIG. 8 shows schematically a view of an example of a tube 30 of the tubular element 1.

[0061] A distance between the center portions C of the first separation wall 33 and the second separation wall 34 can be larger than respective distances at the top wall 37 and the bottom wall 38.

[0062] The first separation wall 33 and the second separation wall 34 can be arcuate. The purpose of the arcuate shape is to draw the filler material along to provide enough material to connect adjacent elements, in particular the first separation wall 33, second separation wall 34, the top wall 37, the bottom wall 38 and the dividing wall 13. Thanks to the first separation wall 33 and the second separation wall 34 being arcuate the material can be evenly distributed, through capillary action, between those elements, which leads to a robust and sealed connection. Such connection is essential if the fluid is to be prevented from leaking between the inlet chamber 11 and the outlet chamber 12. It allows also accommodating the dividing wall 13, which thanks to presence of a separation space 35 does not have to be minimized and hence can simplify the manufacturing considerations, e.g. stamping process for the primary tank 10.

[0063] The arcuate first separation wall 33 and the second separation wall 34 can extend over the whole length of the tube 30 in order to accommodate standard extrusion process.

[0064] The dividing wall 13 can be in contact with the first separation wall 33 and the second separation wall 34.

[0065] The first separation wall 33 and the second separation wall 34 can be bent away from each other.

[0066] The first separation wall 33 and the second separation wall 34 can be bent away from each other along the whole length of the tube 30.

[0067] Alternatively, the first separation wall 33 and the second separation wall 34 can be bent away from each other only in the vicinity of the primary tank 10, for example as a process step using a widening tool introduced into the separation space 35.

Claims

1. A tubular element for a heat exchanger, comprising:a primary tank with an inlet chamber and an outlet chamber for a heat exchange fluid,a secondary tank,a tube extending between the primary tank and the secondary tank, with a set of inlet channels and a set of outlet channels, configured so as to provide U-flow for the fluid within the tubular element,wherein the primary tank includes a dividing wall between the inlet chamber and the outlet chamber,wherein the tube includes a first separation wall and a second separation wall with a separation space between the first separation wall and the second separation wall,the first separation wall and the second separation wall being configured to block fluid flow between the set of inlet channels and the set of outlet channels within the tube,wherein the dividing wall is in contact with the first separation wall and the second separation wall, wherein the set of inlet channels includes a first inlet channel limited by the first separation wall and an inlet channel wall, and wherein the set of outlet channels includes a first outlet channel limited by the second separation wall and an outlet channel wall,wherein a distance between the first separation wall and the second separation wall is smaller than a distance between the first separation wall and the inlet channel wall and is smaller than a distance between the second separation wall and the outlet channel wall.

2. The tubular element according to claim 1, wherein center portions of the first separation wall and the second separation wall are in contact.

3. The tubular element according to claim 2, wherein the first separation wall and the second separation wall are in contact only in the vicinity of the primary tank.

4. The tubular element according to claim 1, wherein the first separation wall and the second separation wall are mechanically pinched towards each other.

5. The tubular element according to claim 1, wherein the first separation wall and the second separation wall are arcuate.

6. The tubular element according to claim 1, wherein the first separation wall and the second separation wall are bent away from each other.

7. The tubular element according to claim 6, wherein the tube includes a top wall and a bottom wall opposite the top wall, with the set of inlet channels and the set of outlet channels being arranged between the top wall and the bottom wall, wherein a distance between center portions of the first separation wall and the second separation wall is larger than respective distances at the top wall and the bottom wall.

8. The tubular element according to claim 1, wherein the first separation wall and the second separation wall are bent away from each other along the whole length of the tube.

9. The tubular element according to claim 1, wherein the first separation wall and the second separation wall are bent away from each other only in the vicinity of the primary tank.

10. The tubular element according to claim 1, wherein the dividing wall 13, the first separation wall and the second separation wall are brazed to each other.

11. The tubular element according to claim 1, wherein the first inlet channel includes an inlet flat section at the inlet channel wall, while the first outlet channel includes an outlet flat section at the outlet channel wall.

12. The tubular element according to claim 1, wherein the tube includes a top wall and a bottom wall opposite the top wall, with the set of inlet channels and the set of outlet channels being arranged between the top wall and the bottom wall, wherein the first separation wall and the second separation wall extend between the top wall and the bottom wall.

13. The tubular element according to claim 1, wherein the tube includes a top wall and a bottom wall opposite the top wall, with the set of inlet channels and the set of outlet channels being arranged between the top wall and the bottom wall, wherein the inlet channel wall and the outlet channel wall extend between the top wall and the bottom wall.

14. The tubular element according to claim 1, wherein the set of inlet channels includes a plurality of second inlet channels of a rectangular shape in cross-section, arranged in series next to each other, while the set of outlet channels includes a plurality of second outlet channels of a rectangular shape in cross-section, arranged in series next to each other.

15. The tubular element according to claim 1, wherein the tube extends along a meandering path between the primary tank and the secondary tank.

16. The tubular element according to claim 1, wherein the primary tank is formed from two shaped portions connected to each other.

17. The tubular element according to claim 16, wherein the two shaped portions are connected to each other by crimping tabs present on at least one of the two shaped portions.

18. The tubular element according to claim 16, wherein each of the two shaped portions includes a dividing wall component extending towards the other of the two shaped portions so that the dividing wall components are connected to each other and together they form the dividing wall.

19. A tube for a tubular element of a heat exchanger, comprising:a set of inlet channels and a set of outlet channels,a first separation wall and a second separation wall with a separation space between the first separation wall and the second separation wall,the first separation wall and the second separation wall being configured to block fluid flow between the set of inlet channels and the set of outlet channels within the tube,wherein the set of inlet channels includes a first inlet channel limited by the first separation wall and an inlet channel wall, and wherein the set of outlet channels includes a first outlet channel limited by the second separation wall and an outlet channel wall,wherein the set of inlet channels includes a plurality of second inlet channels of a rectangular shape in cross-section, arranged in series next to each other, while the set of outlet channels includes a plurality of second outlet channels of a rectangular shape in cross-section, arranged in series next to each other,wherein a distance between the first separation wall and the second separation wall is smaller than a distance between the first separation wall and the inlet channel wall and is smaller than a distance between the second separation wall and the outlet channel wall,wherein the first inlet channel includes an inlet flat section at the inlet channel wall, while the first outlet channel includes an outlet flat section at the outlet channel wall,wherein the first inlet channel includes an inlet arcuate structure at the first separation wall, while the first outlet channel includes an outlet arcuate structure at the second separation wall.

Images