Three-layer bubble film cooling plate

Abstract

Method for producing a cooling plate (10), comprising: Stacking three metal sheets (12, 14, 16) on top of each other, each of the three metal sheets (12, 14, 16) being flat; Attaching one edge of the three metal sheets (12, 14, 16) to each other; Joining an upper one of the metal sheets (16) to a middle one of the metal sheets (14) at a plurality of first locations; Joining a lower one of the metal sheets (12) to the middle one of the metal sheets (14) at a plurality of second locations different from the plurality of first locations; Supplying a pressure medium between the upper one of the metal sheets (16) and the lower one of the metal sheets (12) to separate the upper one of the metal sheets (16) from the lower one of the metal sheets (12) and to deform the middle one of the metal sheets (14); characterized in that for stacking, the three metal sheets (12, 14, 16) are each provided as aluminum sheets (12, 14, 16); wherein the fastening step comprises providing an edge weld (17) around the entire circumference of the aluminum sheet stack (12, 14, 16), by which edge weld the three aluminum sheets (12, 14, 16) are joined together.

Description

INTRODUCTION

[0001] The present invention relates to a method for producing a three-layer bubble film cooling plate according to the preamble of claim 1, as is essentially known from DE 44 26 097 A1.

[0002] Cold plates are primarily manufactured using two processes: extrusion and brazing. Cold plates manufactured by extrusion have thick walls, generally greater than 0.4–0.5 mm thick. Furthermore, the extrusion process is limited by the shape and size of the plates. Brazing is a slow and expensive process that requires numerous fixtures and specialized manufacturing.

[0003] Accordingly, it is desirable to provide an alternative method for manufacturing a cooling plate with reduced cost and time expenditure. SUMMARY

[0004] According to the invention, a method for producing a cooling plate is presented, which is characterized by the features of claim 1.

[0005] According to another aspect, the middle of the aluminum sheets may be thinner than the upper and lower of the aluminum sheets.

[0006] According to another aspect, the pressure medium is compressed air.

[0007] According to another aspect, one of the upper aluminum sheet and the lower aluminum sheet comprises a coolant inlet opening and one of the upper aluminum sheet and the lower aluminum sheet comprises a coolant outlet opening.

[0008] According to another aspect, joining the upper one of the aluminum sheets to the middle one of the aluminum sheets and joining the lower one of the aluminum sheets to the middle one of the aluminum sheets comprises one of laser welding, friction welding, resistance welding, or roll joining.

[0009] According to another aspect, joining the edges of the three metal sheets comprises one of laser welding, friction welding, resistance welding, or roll joining.

[0010] According to a further aspect, joining the upper one of the aluminum sheets to the middle one of the aluminum sheets at a plurality of first locations and joining the lower one of the aluminum sheets to the middle one of the aluminum sheets at a plurality of second locations each comprise a plurality of line welds.

[0011] According to another aspect, joining the upper one of the aluminum sheets to the middle one of the aluminum sheets at a plurality of first locations and joining the lower one of the aluminum sheets to the middle one of the aluminum sheets at a plurality of second locations each comprise a plurality of tack welds.

[0012] Further areas of applicability of the present invention will become apparent from the detailed description, claims, and drawings. The detailed description and specific examples are provided for illustrative purposes only. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] The present invention will be better understood from the detailed description and the accompanying drawings, in which: Fig. 1 is a schematic view of the cold plate according to the principles of the present invention; Fig. Figure 2a is a schematic cross-sectional view of a stack of aluminum sheets according to the principles of the present invention; Fig. Figure 2b is a schematic cross-sectional view of a plurality of weld locations between a stack of aluminum sheets according to the principles of the present invention; Fig. 3 is a schematic plan view of the stack of aluminum sheets showing exemplary weld lines between a top one of the aluminum sheets and a middle one of the aluminum sheets, and between a bottom one of the aluminum sheets and the middle one of the aluminum sheets, according to the principles of the present invention; Fig. 4 is a schematic plan view of the stack of aluminum sheets showing exemplary tack welds between a top one of the aluminum sheets and a middle one of the aluminum sheets, and between a bottom one of the aluminum sheets and the middle one of the aluminum sheets, according to the principles of the present invention; Fig. 5a-5c illustrate an expansion of the cooling plate from its original stacked and welded state to an intermediate and final expansion position.

[0014] Reference numerals may be reused in the drawings to identify similar and / or identical elements. DETAILED DESCRIPTION

[0015] With reference to Fig. 1, a three-layer bubble film cold plate 10 is shown in accordance with the principles of the present invention. The cold plate 10 includes a bottom layer of aluminum sheet 12, a middle layer of aluminum sheet 14, and an top layer of aluminum sheet 16. The bottom aluminum sheet 12 is joined to the middle aluminum sheet 14 by a first plurality of welds 18, and the top aluminum sheet 16 is joined to the middle aluminum sheet 14 by a second plurality of welds 20 offset from the first plurality of welds 18.

[0016] With reference to Fig. 2a and Fig. 2b, a method for manufacturing the three-layer bubble film cooling plate 10 according to the principles of the present invention will now be described. In Fig. 2a, the lower layer of aluminum sheet 12, the middle layer of aluminum sheet 14, and the upper layer of aluminum sheet 16 are stacked on top of each other, while they are all generally flat sheets. The middle aluminum sheet 14 may be thinner and more flexible than the upper layer of aluminum sheet 16 and the lower layer of aluminum sheet 12. For example, the upper and lower aluminum sheets 12, 16 may be 2 to 4 times thicker than the middle aluminum sheet 14. Then, as in Fig. 2b, an edge weld 17 or other fastening method is applied around the perimeter of the aluminum sheet stack to join the aluminum sheets 12, 14, and 16 together. Then, the lower aluminum sheet 12 is joined to the middle aluminum sheet 14 by a plurality of welds 18, and the upper aluminum sheet 16 is joined to the middle aluminum sheet 14 by a plurality of welds 20.

[0017] With reference to Fig. 3 shows a plan view of the stack of aluminum sheets 12, 14, 16, wherein the solid lines 18 illustrate a plurality of elongated welds 18 between the lower aluminum sheet 12 and the middle aluminum sheet 14. Furthermore, the dashed lines 20 illustrate a plurality of elongated welds 20 between the upper aluminum sheet 16 and the middle aluminum sheet 14. The elongated welds 18 and 20 can be straight or curved. The elongated welds 18 and 20 are offset from one another to form channels 22, 24 in the lower layer of aluminum sheet 12 and the middle layer of aluminum sheet 14 and the upper layer of aluminum sheet 16 and the middle layer of aluminum sheet 14. With reference to Fig. 3, the lower layer of aluminum sheet 12 and the upper layer of aluminum sheet 16 or both may be provided with a coolant inlet opening 26 and a coolant outlet opening 28.

[0018] With reference to Fig. 5a-5c, an expansion method for expanding the welded aluminum sheets 12, 14, 16 will now be described. With reference to Fig. 5a, the welded stack of aluminum sheets 12, 14, 16 can be placed in an expandable or fixed color. A source of a pressure medium 30, such as compressed air or liquid, can be attached to the coolant inlet and / or outlet opening to supply the pressure medium into the channels 22, 24 between the stacked aluminum plates. Air can be used for thinner aluminum sheets, and water or another liquid can be used for thicker aluminum sheets. With reference to Fig. 5b, the structure of the stacked aluminum plates is partially stretched and the upper color element is placed in an intermediate position, and in Fig. 5c, the channels 22, 24 between the stacked aluminum plates are fully formed, and the upper and lower metal sheets reach the desired expansion position. A leak test can be performed during the inflation process.

[0019] Alternatively, as in Fig. 4, a plan view of the stack of aluminum sheets 12, 14, 16 can be seen, wherein the solid circular lines 18' represent a plurality of spot welds 18' between the lower aluminum sheet 12 and the middle aluminum sheet 14. Furthermore, the dashed circular lines 20' illustrate a plurality of spot welds 20' between the upper aluminum sheet 16 and the middle aluminum sheet 14. The spot welds 18 and 20 are offset from one another to form channels in the lower layer of aluminum sheet 12 and the middle layer of aluminum sheet 14 and the upper layer of aluminum sheet 16 and the middle layer of aluminum sheet 14, respectively. With reference to Fig. 4, the lower layer of aluminum sheet 12 and the upper layer of aluminum sheet 16 or both may be provided with a coolant inlet opening 26 and a coolant outlet opening 28.

[0020] The stack of aluminum sheets 12, 14 and 16, which are welded together by spot welds 18', 20', can then be expanded by introducing a pressure medium, as described above with reference to Fig. 5a-5c. It should be noted that a combination of spot and line welds can also be used to form the three-layer cooling plate 10.

[0021] The present invention provides a method for manufacturing predominantly flat, double-sided cold plates 10 using a weld and inflate process. Three flat aluminum sheets are placed on top of each other. Two of the three metal sheets are joined using controlled partial penetration laser welding or friction welding. Air is forced through the welded stack at a predetermined pressure based on the metal sheet thicknesses and required channel heights to inflate the metal sheets and create the channel structure. The middle plate deforms so that the two outer plates are flat, or generally flat, to contact the battery walls. The cold plate requires inexpensive, simple tooling compared to previous cold plate designs. The process avoids stamping operations and tooling normally required for brazing.Several joining methods are available, including laser welding, friction welding, or roll bonding. Suitable masking films can be used to prevent bonding in the masked areas. Mixed coolant channel areas through partial channel welding can reduce the risk of coolant evaporation during a thermal event in the cell. The simple forming process using three flat aluminum sheets without trimming or preforming reduces the cost and time for prototyping and production.

Claims

[1] A method for manufacturing a cooling plate (10), comprising: Stacking three metal sheets (12, 14, 16) on top of each other, each of the three metal sheets (12, 14, 16) being flat; Attaching one edge of the three metal sheets (12, 14, 16) to each other; Joining an upper one of the metal sheets (16) to a middle one of the metal sheets (14) at a plurality of first locations; Joining a lower one of the metal sheets (12) to the middle one of the metal sheets (14) at a plurality of second locations different from the plurality of first locations; Supplying a pressure medium between the upper one of the metal sheets (16) and the lower one of the metal sheets (12) to separate the upper one of the metal sheets (16) from the lower one of the metal sheets (12) and to deform the middle one of the metal sheets (14); characterized by , that for stacking, the three metal sheets (12, 14, 16) are each provided as aluminum sheets (12, 14, 16); wherein the fastening step comprises providing an edge weld (17) around the entire circumference of the aluminum sheet stack (12, 14, 16), by which edge weld the three aluminum sheets (12, 14, 16) are joined to one another. [2] The method of claim 1, wherein the middle one of the metal sheets (14) is thinner than both the upper one of the metal sheets (16) and the lower one of the metal sheets (12). [3] The method according to claim 1, wherein the pressure medium is compressed air. [4] The method of claim 1, wherein one of the upper metal sheet (16) and the lower metal sheet (12) comprises a coolant inlet opening (26) and one of the upper metal sheet (16) and the lower metal sheet (12) comprises a coolant outlet opening (28). [5] The method of claim 1, wherein joining the upper one of the metal sheets (16) to the middle one of the metal sheets (14) and joining the lower one of the metal sheets (12) to the middle one of the metal sheets (14) comprises one of laser welding, friction welding, resistance welding, and roll joining. [6] The method of claim 1, wherein securing the edge of the three metal sheets (12, 14, 16) to each other comprises one of laser welding, friction welding, resistance welding, and roll bonding. [7] The method of claim 1, wherein joining the upper one of the metal sheets (16) to the middle one of the metal sheets (14) at a plurality of first locations and joining the lower one of the metal sheets (12) to the middle one of the metal sheets (14) at a plurality of second locations each comprises a plurality of line welds (18, 20). [8] The method of claim 1, wherein joining the upper one of the metal sheets (16) to the middle one of the metal sheets (14) at a plurality of first locations and joining the lower one of the metal sheets (12) to the middle one of the metal sheets (14) at a plurality of second locations each comprises a plurality of tack welds (18, 20).

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