A liquid container that regulates the temperature of a battery cell with two substrates

Abstract

The present invention describes a liquid container for thermoregulating a battery cell (1) comprising two substrates (2a, 2b) that, in an assembled state, define a flow path (3), one substrate (2a) having an at least partially circumferential groove (7) and one substrate (2b) having an at least partially circumferential tongue (8) for fitting into the groove (7) for ultrasonic welding. It is intended that, prior to ultrasonic welding, the width (11) of the tongue (8) exceeds the width (12) of the groove (7) and the side surface (13) of the tongue (8) abuts against the groove wall (14) to form a circumferential weld, in order to enable a stable and liquid-tight connection between the substrates (2a, 2b).

Description

[Technical field]

[0001] The present invention relates to a liquid container for regulating the temperature of a battery cell having two substrates which, when assembled, define a flow path, one substrate having an at least partially circumferential groove for ultrasonic welding and one substrate having an at least partially circumferential tongue for fitting into the groove. [Background technology]

[0002] A device for thermoregulating battery cells is known from DE 10 200 03 133 A1. This device comprises two substrates which can be connected to one another by an ultrasonic welding process, the two substrates defining a flow passage for a thermoregulating fluid. The substrates form through openings in which the battery cells are fitted. For ultrasonic welding to one another, one substrate comprises a circumferential groove and the other substrate comprises a circumferential tongue which engages in the groove. The tongue tapers towards the groove bottom and forms an energy director which abuts against the groove bottom before ultrasonic welding, whereby a circumferential weld line is created between the energy director tip and the groove bottom. By inducing ultrasonic waves, frictional heat is created at this weld line, which melts the tongue and the groove. Disadvantageously, this surface welding requires a relatively high and long energy input, since otherwise the material melted by the energy director solidifies before forming a solid connection with the groove, and therefore the fluid-tightness of the flow passage cannot be guaranteed. On the other hand, however, the required increased energy input can damage the substrate at the contact surface between the sonotrode and the substrate. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Austrian Patent No. 522361 Summary of the Invention [Problem to be solved by the invention]

[0004] The object of the present invention is therefore to provide a liquid container of the type mentioned at the beginning, the base bodies of which can be connected quickly with low energy input and at the same time enable a stable and liquid-tight connection between the base bodies, in particular a liquid-tight connection in the event of overpressure. [Means for solving the problem]

[0005] The invention solves the problem by forming a circumferential weld surface, in which the width of the tongue exceeds the width of the groove and the lateral surface of the tongue adjoins the groove wall, before ultrasonic welding. As a result of the measures according to the invention, the tongue is clamped between the groove walls under pretension, thereby forming two contact surfaces to be used as welding surfaces between the respective lateral surface of the tongue and the respective groove wall. Due to this additional force input, even a relatively low energy input from the sonotrode leads to melting of the weld surface. In the process, during ultrasonic melting, a shear flow is created between the groove wall and the lateral surface of the tongue, which promotes material mixing of the melts of the different substrates and thus a uniform connection. By providing two weld surfaces between the respective lateral surface of the tongue and the respective groove wall, a double mash seam is created after the ultrasonic welding process, which on the one hand ensures redundant fluid-tight protection of the substrates and on the other hand improves mechanical stability by doubling the weld cross-section. Thus, the sealing conditions improve, especially in liquid containers, especially inside the liquid, in case of overpressure, i.e. in case of internal pressure exceeding the external pressure. Basically, only a part of each side of the tongue serves as a welding surface, the larger the welding surface, the more stable the welded joint. Preferably, the side of the tongue may abut the groove wall all over. In a preferred embodiment, the side of the tongue and the groove wall run parallel to each other. The width of the tongue preferably means the maximum width of the tongue base, i.e. the part of the tongue that runs into the groove, which does not form a possibly tapering tongue head. The base, preferably the base that forms the groove, may be formed as a sealing plate that serves as a cover for the other base that opens towards the sealing plate. The tongue and the groove may be formed partially circumferentially. In this case, several tongue-and-groove connections that are separated from each other may be provided. However, preferably, a single tongue-and-groove connection runs around the opening for the battery cell. In this case, the tongue may be formed by a wall of the base that has the tongue. In cross section, the tongue portion tapers towards the groove bottom, which on the one hand facilitates assembly of the base body and on the other hand provides pre-centering of the base body with the tongue in the groove.

[0006] In particular, the liquid container for adjusting the temperature of the battery cell can be a temperature adjustment device for the battery cell. The temperature adjustment device for the battery cell includes at least one battery cell and two substrates, For ultrasonic welding, one substrate has a groove at least partially around the circumference, and one substrate has a tongue at least partially around the circumference for fitting into the groove; Prior to ultrasonic welding, the tongue has a width that exceeds the width of the groove, and the sides of the tongue form a circumferential weld surface that abuts the groove walls. In the assembled state, the substrate can define a flow channel. The battery cells can be at least partially disposed within the flow channel. The flow channel can include an inlet and an outlet for a temperature regulating fluid. The flow channel can be supplied with the temperature regulating fluid via a pump.

[0007] In order to be able to utilize the liquid container for efficient temperature conditioning of the battery cells in contact with the outside of the liquid container, the base body can have through-openings for the individual battery cells and define flow paths. The flow paths can be filled with a temperature conditioning fluid, preferably a temperature conditioning liquid, which flows directly to the battery cells. The end sections of the battery cells can protrude through two through-openings located opposite each other, with a casing section located between the end sections of the battery cells extending into the flow paths. In order to obtain a liquid-tight connection between the battery cells and the through-openings, the through-openings can be provided with a ring seal surrounding the battery cells.

[0008] In this case, particularly when using thermoplastic materials such as polyamide, a sufficient contact force between the groove and the tongue without damaging the tongue occurs when the width of the tongue exceeds the width of the groove by 0.1 mm to 0.8 mm, preferably 0.3 mm to 0.5 mm.

[0009] In order to allow for focused evacuation of the melt during ultrasonic welding and at the same time further improve the stability and tightness of the connection between the substrates, it is contemplated that a cavity is provided between the groove bottom and the tongue top of the tongue that is fitted in before welding. Thus, the tongue does not insert into the groove until it butts, but leaves a cavity. This creates a reservoir into which the melt generated during the ultrasonic welding process can flow and into which it can solidify. To ensure the cavity, one of the substrates can form a stop for the stop surface of the other substrate, which is arranged in such a way that their interaction prevents the tongue from hitting the groove bottom.

[0010] In order to provide a sufficiently large volume to accommodate the melt without increasing the required energy input and without weakening the welded connection, the height of the cavity can correspond to 10% to 60% of the height of the groove. Below 10%, the melt cannot be sufficiently absorbed. Above 60%, on the one hand, the welding surface is too small and, on the other hand, the clamping force acting from the groove to the tongue is excessively reduced. As a result, these must be compensated for by increasing the energy input generated by the sonotrode.

[0011] The melt not only flows into the cavity, but also flows out from the side of the welding surface opposite the cavity. If the melt flows along the inside of the substrate towards the flow channel and solidifies there, this may have a negative effect on the temperature regulation of the battery cell by changing the intended flow behavior. If the melt flows towards the outside of the substrate, connections or other components may be adversely affected. In order to ensure that the flowing melt does not impair the functionality of the device, it is therefore recommended in a preferred embodiment of the device according to the invention that the substrate with the groove has a melt channel adjacent to the groove in the direction of the other substrate. The melt channel has a greater width than the groove, which results in melt channel sections on both sides of the tongue, along which the melt emerging from the molten bath can flow, cool and solidify before reaching other areas of the device.

[0012] If the height of the welded surface between the side surface of the tongue and the groove wall is 1 mm to 3 mm, in particular 1.4 mm to 1.7 mm, a sufficiently high stability of the connection between the base bodies can be achieved.

[0013] To prevent deformation of the tongue when the substrates are assembled and at the same time save material costs, the tongue base may be 1 mm to 2 mm wide, in particular 1.2 mm to 1.4 mm wide.

[0014] A particularly compact arrangement is obtained if the grooves extend in the joining direction of the base bodies at the level of the through-openings of the base bodies in which they are provided, in particular the grooves are spaced apart from the through-openings transversely to the joining direction of the base bodies to be assembled in the direction of the edge regions of the base bodies, so that unintentional melting of the through-openings or their seals can be prevented, since the through-openings are not in the near field of the sonotrode.

[0015] The subject matter of the invention is illustrated in the drawings. [Brief description of the drawings]

[0016] [Figure 1] 1 shows a schematic cross-sectional view of an apparatus of the present invention for temperature regulating a battery cell. [Diagram 2] FIG. 1 shows a detailed view of the tongue and groove connection before assembly of the substrates and before ultrasonic welding. [Diagram 3] FIG. 1 shows a detailed view of the tongue and groove connection after the substrates are assembled and before ultrasonic welding. [Figure 4] 1 shows a detailed view of the tongue and groove connection after the substrates are assembled and ultrasonically welded. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The device for temperature regulation of a liquid container, in particular a battery cell 1, according to the invention comprises two base bodies 2a, 2b, which in the assembled state define a flow path 3, as can be seen from FIG. 1. The base bodies 2a, 2b may comprise through-openings 4 for the battery cells 1. In this case, two through-openings 4 can be provided for each battery cell 1, which are arranged opposite each other and in the respective base bodies 2a, 2b and which respectively accommodate the battery cell 1 at their end sides. As a result, the section of the battery cell 1 which is arranged between the through-openings 4 extends into the flow path 3 and can be directly flowed by the temperature regulation fluid. The base body 2a is configured as a sealing plate and serves as a cover for the other base body 2b which opens towards the sealing plate. The base body 2a may have a flow divider 5 which projects into the flow path 3, which allows an induced circulation of the temperature regulation fluid around the battery cell 1. Thereby, they can form a receiving section for the centering dome 6, which is arranged on the inner bottom surface of the base body 2b, so that the flow distributors 5 can be aligned in the position intended for them.

[0018] As can be seen in particular from FIGS. 2 and 3, the base body 2a has a groove 7 and the base body 2b has a tongue 8, by means of which the base bodies 2a, 2b can be plugged into one another and then joined to one another in a material-joint manner by ultrasonic welding. The groove 7 and the tongue 8 can extend partially transversely to the joining direction 9, but can also preferably be configured continuously, so that the tongue 8 can be formed from the wall 10 of the base body 2b. According to the invention, the width 11 of the tongue 8, in particular the maximum width of the tongue base extending inside the groove, is greater than the width 12 of the groove 7 before ultrasonic welding. In this way, in the plugged state, a circumferential contact surface is formed between the side surface 13 of the tongue 8 and the groove wall 14, respectively, which serves as a welding surface 15. Thus, after ultrasonic welding, a double-circumferential mash seam is formed, which can increase the stability and fluid-tightness of the device.

[0019] The width 11 of the tongue 8 may exceed the width 12 of the groove 7 by 0.4 mm.

[0020] As disclosed in Figures 2 and 3, a cavity 18 may be provided between the groove bottom 16 and the tongue top 17, which cavity may accommodate melt exiting from the molten bath (see Figure 4). The height 19 of the cavity 18 may be 50% of the height 20 of the groove 7.

[0021] The substrate 2a with the groove 7 may be provided with a melt channel 21 adjacent to the groove 7 in the direction of the other substrate 2b and which may be wider than the groove 7. In this way, as shown in Figure 4, two melt channel sections 22 are formed along which the melt emerging from the molten bath can flow and solidify during cooling.

[0022] The height 23 of the weld surface 15 may be 1.5 mm. The tongue base width 11 may be 1.33 mm.

[0023] In the sense of a compact device, the groove 7 may extend in the area of ​​the through opening 4. The through opening 4 may have a seal 24 for the battery cell 1.

Claims

1. A liquid container for temperature - regulating a battery cell (1) comprising two substrates (2a, 2b) that define a flow path (3) in an assembled state, For ultrasonic welding, one substrate (2a) has at least a partially circumferential groove (7), One substrate (2b) has at least a partially circumferential tongue (8) for fitting into the groove (7), In the liquid container, Before ultrasonic welding, the width (11) of the tongue (8) exceeds the width (12) of the groove (7), and the side surface (13) of the tongue (8) forms a circumferential weld that abuts against the groove wall (14). A liquid container characterized by this.

2. A device for temperature - regulating a battery cell (1) having the liquid container according to claim 1, wherein the substrates (2a, 2b) for temperature - regulating the battery cell (1) are provided with through - openings (4) for individual battery cells (1) and define a flow path (3).

3. The device according to claim 2, characterized in that the width (11) of the tongue (8) exceeds the width (12) of the groove (7) by 0.1 mm to 0.8 mm, preferably 0.3 mm to 0.5 mm.

4. The device according to claim 2 or 3, characterized in that a cavity (18) is provided between the bottom of the groove (16) and the tongue tip (17) of the tongue (8) fitted therein before welding.

5. The device according to claim 4, characterized in that the height (19) of the cavity (18) corresponds to 10% to 60% of the height (20) of the groove (7).

6. The device according to claim 2 or 3, characterized in that the substrate (2a) having the groove (7) has a melt channel (21) adjacent to the groove (7) in the direction of the other substrate (2b).

7. The height (23) of the weld surface (15) between the side surface (13) of the tongue (8) and the groove wall (14) is 1 mm to 3 mm, particularly 1.4 mm to 1.7 mm. The device according to claim 2 or 3, characterized by this.

8. The device according to claim 2 or 3, characterized in that the width of the tongue base is 1 mm to 2 mm, particularly 1.2 mm to 1.4 mm.

9. The device according to claim 2 or 3, characterized in that the groove (7) extends at the height of the through - opening (4) of the substrate (2a) in which the groove (7) is provided in the joining direction (9) of the substrates (2a, 2b).

10. A temperature control device comprising at least one battery cell and two substrates (2a, 2b), For ultrasonic welding, one substrate (2a) comprises a groove (7) that at least partially circumscribes, One substrate (2b) comprises a tongue (8) that at least partially circumscribes for fitting into the groove (7), In the temperature control device, Before ultrasonic welding, the width (11) of the tongue (8) exceeds the width (12) of the groove (7), and the side surface (13) of the tongue (8) abuts against the groove wall (14) to form a circumferential welding surface, characterized in that it is a temperature control device.

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