Expansion tank and battery cooling system

Abstract

The invention relates to an expansion tank (1) for a battery cooling system (3), - comprising a tank body (4) having a first cover (5) having a threaded end piece (6) and a second cover (11), - comprising a drying cartridge (7), which is screwed onto the threaded end piece (6) of the first cover (5), - a vacuum valve (8) being arranged in the first cover (5), via which, when a vacuum prevails in the expansion tank (1), fresh air (2a) is supplied from the environment via the drying cartridge (7) into the expansion tank (1), - a pressure relief valve (9) being arranged in the second cover (11), via which, when an excess pressure prevails in the expansion tank (1), air (2) is supplied from the expansion tank (1) into the environment. This allows for an easy-to-assemble and economical design of the expansion vessel (1).Figure for abstract: (Fig 1).

Description

Title of the invention: Expansion tank and battery cooling system

[0001] The present invention relates to an expansion tank for a battery cooling system. The invention further relates to a battery cooling system comprising such an expansion tank.

[0002] For environmental aspects, electric or hybrid vehicles are increasingly in the consumer's focus and are therefore also increasingly spreading onto the streets. In order to be able to increase both the autonomy and the performance of these electric or hybrid vehicles, it is sought to maintain a traction battery of such an electric or hybrid vehicle within an optimal temperature window for this traction battery, temperature control devices, in particular cooling devices, being used in a known manner for this purpose. In order to obtain particularly effective cooling, so-called immersion cooling is also used, in which a dielectric, i.e. non-electroconductive, cooling liquid bathes the individual battery elements of the traction battery.

[0003] Such a battery cooling system for cooling in particular a traction battery therefore also comprises an expansion tank in which air is stored as an expansion cushion for a volume change caused by the temperature of the coolant. An increase in temperature causes the coolant to expand, which, if the resulting excess pressure cannot escape, could lead to a high pressure load in the expansion tank and possibly damage it, which must be avoided. For this reason, such expansion tanks generally have a connection to the environment, in order to be able to reduce, if necessary, a pressure difference caused by the temperature by blowing air out into the environment.When the coolant cools down, it contracts, which creates a negative pressure in the expansion tank and causes fresh air to be drawn in from the environment. By the term "fresh air" one can / must understand the ambient air. In order to prevent or, as the case may be, at least reduce the unwanted introduction of moisture into the coolant, so-called drying cartridges are provided, in which a desiccant is arranged through which fresh air drawn in from the environment has passed during the suction process and which thus absorbs the moisture and dries the drawn-in fresh air.

[0004] The disadvantage of these expansion tanks lies in particular in the relatively difficult installation of a pressure relief valve or, as the case may be, a vacuum valve in a wall of a tank body of the expansion tank.

[0005] The problem underlying the present invention therefore concerns an improved or at least alternative embodiment for an expansion vessel, which makes it possible to overcome the known drawbacks of the prior art.

[0006] The present invention is based on the general idea of ​​not having, as was the case until now, a pressure relief valve or, as the case may be, a vacuum valve in a wall of a vessel body of an expansion vessel for air in a battery cooling system, but of integrating these valves in two covers which are only installed on the vessel body of the expansion vessel in the assembled state, whereby the assembly of the valves is considerably simplified. The expansion vessel serves to buffer a volume of air due to a volume change caused by the temperature of a coolant, in particular oil.The expansion tank according to the invention, in particular for air, for a battery cooling system has the aforementioned tank body, comprising a first cover provided with a threaded end piece and a second cover, comprising a drying cartridge, which can be screwed onto the threaded end piece of the first cover, the vacuum valve being arranged in the first cover, via which, in the event of a vacuum prevailing in the expansion tank, fresh air can be drawn from the environment via the drying cartridge and the threaded end piece, which can be designed hollow, into the expansion tank. The pressure relief valve is arranged in the second cover, via which, in the event of an excess pressure prevailing in the expansion tank, air can be blown out of the expansion tank into the environment.An activated carbon filter can of course also be provided here, so that the air blown out via the pressure relief valve in the event of excess pressure in the vessel body can still flow through the activated carbon filter and be purified there of hydrocarbons. A desiccant, in particular a molecular sieve, for example zeolite, is arranged in the drying cartridge. Due to the arrangement of the vacuum valve in the first cover and the pressure relief valve in the second cover, these can be mounted relatively easily, even before both covers are installed on the vessel body. In particular, this can avoid mounting on an inner wall of the vessel body that is only very difficult to access. This can also considerably simplify the replacement of such a valve in the event of maintenance or repair.

[0007] Conveniently, the first cover and / or the second cover are made of metal, in particular aluminum. The use of aluminum allows a weight-optimized and at the same time strong construction method. Aluminum is also easy to machine, for example to drill, whereby there is in particular also a simple possibility of fixing the vacuum valve, for example in a bore provided with an internal thread.

[0008] In an advantageous development of the invention, the vase body is made of metal, in particular aluminum. The vase body can thus be produced in the form of an extruded aluminum profile or a part formed by deep drawing from aluminum. For example, the vase body can be tubular in shape, which is entirely suitable for an extrusion process. A deep drawing process is also suitable for economical and high-quality production of the vase body, since deep drawing offers other shaping possibilities.

[0009] In another particularly preferred embodiment of the expansion vessel, the vessel body is made of a synthetic material, in particular polyoxymethylene (POM). POM is a partially crystalline thermoplastic with high mechanical strength and rigidity and furthermore high wear resistance as well as low moisture absorption, which is particularly advantageous when used for the expansion vessel according to the invention, since in this case an incorporation of water or, as the case may be, an absorption of moisture increases the electrical conductivity of a dielectric coolant. In order to be able to further increase the mechanical strength as well as the wear resistance, the synthetic material may have glass fibers, in particular 25% glass fibers, in particular be produced as POM GF-25.The vessel body can also be produced as an injection-moulded plastic part. The production as an injection-moulded plastic part offers the great advantage of being able to produce the vessel body and thus also the expansion vessel not only with high quality but at the same time also economically.

[0010] Advantageously, the drying cartridge has a molecular sieve, in particular zeolite. The zeolite may, for example, be spherical in shape and absorb moisture without any further energy input. An exothermic reaction thus occurs.

[0011] In another advantageous embodiment of the expansion vessel, the vacuum valve opens at a vacuum pi of - 0.3 bar > pi > - 0.5 bar and the pressure relief valve can open at an overpressure p2 of 0.4 bar < p2 < 1.0 bar. These vacuums / overpressures make it possible to tolerate a certain overpressure / vacuum in the vessel body, whereby the air renewal cycles can be reduced and the service life of the drying cartridge can be extended. Generally, without such valves, fresh air would be continuously drawn in from the environment or air would be continuously expelled into the environment, which would greatly reduce the service life of the drying cartridge as well as an HC absorber. The following applies: the higher or lower the opening pressure, the fewer renewal cycles there are.

[0012] Particularly preferably, the first cover and / or the second cover are sealed with respect to the vessel body by means of a seal made of AEM (ethylene acrylate rubber) or a seal made of HNBR (hydrogenated nitrile rubber). Furthermore, use for the most diverse materials is possible. Ethylene acrylate rubber (AEM) is a polymer of ethylene methyl acrylate and a monomer proportion having carboxylic acid groups. AEM is heat-resistant and is resistant to chemicals and oil. HNBR has a high fluid resistance, a high abrasion resistance and good mechanical properties. Both synthetic materials are therefore predestined for use as seals for the expansion vessel according to the invention.

[0013] The present invention is furthermore based on the general idea of ​​equipping a battery cooling system with an expansion tank described in the above paragraphs and thus transferring the advantages described with respect to the expansion tank to the battery cooling system. Specifically, the advantages of a battery cooling system equipped with the expansion tank according to the invention lie in its economical, as it is simple, manufacturing, in particular because pre-assembly of the two valves on the respective associated cover is significantly simpler. For periodic replacement of the drying cartridge, it can also be simply unscrewed from the first cover and a new one can then be screwed on.

[0014] Other important features and advantages of the invention are apparent from the dependent claims, the drawings and the associated description of the figures with the aid of the drawings.

[0015] It is understood that the features mentioned above and still to be explained below are not only usable in the respective combination indicated, but also in other combinations or alone, without departing from the scope of the present invention. The elements mentioned above and still to be mentioned below of a higher unit, such as for example of a device, apparatus or arrangement, which are designated separately, may constitute separate elements or components of this unit or be integral parts or sections of this unit, also when the latter is shown otherwise in the drawing.

[0016] Preferred embodiments of the invention are shown in the drawings and are further explained in the description below, where like reference numerals refer to identical or analogous or functionally identical components.

[0017] We see there, respectively schematically

[0018] [Fig-1] a sectional representation of an expansion vessel according to the invention of a battery cooling system according to the invention,

[0019] [Fig.2] a representation of detail A of [Fig. 1],

[0020] [Fig.3] a representation of detail B of [Fig.l],

[0021] [Fig.4] a sectional representation of a pressure relief valve.

[0022] According to figures 1 to 3, an expansion vessel 1 for air 2 according to the invention of a The battery cooling system 3 according to the invention has a vessel body 4 made of synthetic material having a first cover 5 having a threaded end piece 6 and a second cover 11. A drying cartridge 7 is also provided, which is screwed onto the threaded end piece 6 of the first cover 5. A vacuum valve 8 is arranged in the first cover 5, via which, when a vacuum prevails in the expansion vessel 1, fresh air 2a arrives from the environment via the drying cartridge 7 and the threaded end piece 6 into the expansion vessel 1. The fresh air 2a drawn in can thus be dried.

[0023] A pressure relief valve 9 is arranged in the second cover 11 (see also [Fig. 4]), via which, in the event of excess pressure prevailing in the expansion vessel 1 or, as the case may be, in its vessel body 4, air 2 can be blown out from the expansion vessel 1 into the environment.

[0024] The drying cartridge 7 can be replaced by simply unscrewing the threaded end piece 6 or, as the case may be, screwing it onto it. The drying cartridge 7 may have a molecular sieve, in particular a zeolite, or another desiccant.

[0025] By integrating the two valves 8, 9 into the respective associated cover 5, 11, a complicated and therefore expensive installation of the valves 8, 9 in a wall of the vessel body 4 of the expansion vessel 1 can be dispensed with. The vessel body 4 can thus be produced very simply, for example in the form of a tube. By arranging the vacuum valve 8 in the first cover 5 and the pressure relief valve 9 in the second cover 11, a replacement of such a valve 8, 9 can also be significantly simplified in the event of maintenance or repair, since the valves 8, 9 are significantly more accessible when the covers 5, 11 are removed from the vessel body 4. The expansion vessel 1 serves to buffer a volume of air due to a volume change caused by the temperature of a coolant, in particular oil.

[0026] The first cover 5 and / or the second cover 11 can be made of metal, in particular aluminum, the use of aluminum allowing a weight-optimized and at the same time strong construction method. The aluminum also allows the production of a stable threaded end piece 6, by means of which the drying cartridge 7 can be reliably fixed. Of course, a design of the covers 5, 11 of synthetic material, in particular as an injection-molded part of synthetic material, is also conceivable.

[0027] The vase body 4 can also be made of metal, in particular aluminum, in which case the vase body 4 can be made as an extruded aluminum profile or as a part formed by deep drawing from aluminum. This allows for high-quality and also economical production. A deep drawing method is also suitable for manufacturing the vase body 4.

[0028] The covers 5, 11 can be fixed to the vase body 4 by gluing or screwing, in particular screwing allowing maintenance or, as the case may be, particularly simple repair.

[0029] The vessel body 4 can be made, as can the covers 5, 11, of synthetic material, in particular polyoxymethylene (POM). POM has high mechanical strength and rigidity and furthermore high wear resistance as well as low moisture absorption, which is particularly advantageous when used for the expansion vessel 1 according to the invention, since in this case an incorporation of water or, as the case may be, an absorption of moisture increases the electrical conductivity of a dielectric coolant. Polyketones are also suitable for this purpose. To increase the strength and / or wear resistance, glass fibers, in particular 25% glass fibers, can be incorporated into the synthetic material matrix.The vase body 4 can also be produced as an injection-molded part made of synthetic material, which offers the great advantage of high-quality and economical manufacturing and allows shapes which cannot, for example, be obtained by extrusion.

[0030] A molecular sieve, in particular a zeolite, may be arranged as a desiccant in the drying cartridge 7.

[0031] The vacuum valve 8 can open at a vacuum pi of - 0.3 bar > pi > - 0.5 bar while the pressure relief valve 9 can open at an overpressure p2 of 0.4 bar < p2 < 1.0 bar. These vacuums / overpressures make it possible to tolerate a certain overpressure / vacuum in the vessel body, whereby the air renewal cycles can be reduced and the service life of the drying cartridge 7 can be extended.

[0032] In order to reliably seal an internal space of the vessel body 4, the first cover 5 and / or the second cover 11 are sealed relative to the vessel body 4 by means of a seal 10 made of AEM (ethylene acrylate rubber) or HNBR (hydrogenated nitrile rubber). AEM is heat-resistant as well as chemical and oil-resistant. HNBR has high fluid resistance, high abrasion resistance and good mechanical properties.

[0033] The pressure relief valve 9 shown in [Fig. 4] has a valve body 12 pre-tensioned by means of a spring 13, which is positioned in a sealed manner on an associated valve seat 14 for closing the pressure relief valve 9. The pressure relief valve 9 is sealed with respect to the second cover 7 by means of a sealed O-ring 15. It is of course clear that the pressure relief valve 9 shown in [Fig. 4] can also be used with the same construction, but reversed, as a vacuum valve 8. The pressure relief valve 9 or, as the case may be, the vacuum valve 8 also serves to prevent an inadmissible increase / decrease in the pressure in the coolant circuit. Furthermore, a membrane 16 can be arranged at the vacuum valve 8 or, as the case may be, at the pressure relief valve 9, which membrane prevents unwanted penetration of runoff water.

[0034] The expansion tank 1 also makes it possible to manufacture the battery cooling system 3 economically, since it is simple, in particular because pre-assembly of the two valves 8, 9 on the respective associated cover 5, 11 is significantly simpler. For periodic replacement of the drying cartridge 7, the latter can also be simply unscrewed from the first cover 5 and a new one can then be screwed on.

Claims

Claims

1. Expansion vessel (1) for a battery cooling system (3), - comprising a vessel body (4) comprising a first cover (5) comprising a threaded end piece (6) and a second cover (11), - comprising a drying cartridge (7), which is screwed onto the threaded end piece (6) of the first cover (5), - a vacuum valve (8) being arranged in the first cover (5), via which, when a vacuum prevails in the expansion vessel (1), fresh air (2a) arrives from the environment via the drying cartridge (7) into the expansion vessel (1), - a pressure relief valve (9) being arranged in the second cover (11), via which, when an overpressure prevails in the expansion vessel (1), air (2) arrives from the expansion vessel (1) into the environment.

2. Expansion vessel according to claim 1, characterized in that the first cover (5) and / or the second cover (11) are made of metal, in particular aluminum.

3. Expansion vessel according to claim 2, characterized in that the vessel body (4) is made of metal, in particular aluminum.

4. Expansion vessel according to claim 3, characterized in that the vessel body (4) is made in the form of an extruded aluminum profile or in the form of a part formed by deep drawing in aluminum.

5. Expansion vessel according to claim 1 or 2, characterized in that the vessel body (4) is made of synthetic material, in particular polyoxymethylene (POM) or polyketone.

6. Expansion vessel according to claim 5, characterized in that the synthetic material has glass fibers, in particular a proportion of 25% glass fibers.

7. Expansion vessel according to one of the preceding claims, characterized in that the drying cartridge (7) has a molecular sieve, in particular a zeolite.

8. Expansion vessel according to one of the preceding claims, characterized - in that the vacuum valve (8) opens at a vacuum pi of - 0.3 bar > pi > - 0.5 bar and / or - in that the pressure relief valve (9) opens at an overpressure p2 of 0.4 bar < p2 < 1.0 bar.

9. Expansion vessel according to one of the preceding claims, characterized - in that the first cover (5) is sealed relative to the vessel body (4) by means of a seal (10) made of AEM (ethylene acrylate rubber) or HNBR (hydrogenated nitrile rubber) and / or - in that the second cover (11) is sealed relative to the vessel body (4) by means of a seal (10) made of AEM (ethylene acrylate rubber) or HNBR (hydrogenated nitrile rubber).

10. Battery cooling system (3) comprising an expansion tank (1) according to one of the preceding claims.

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