Air compressor for conveying air with air and coolant cooling

Abstract

The presented invention relates to an air compressor (100) for conveying air, wherein the air compressor (100) comprises: - a stator (101), - a cooling device (103) and - a shell (115) surrounding the stator (101), the cooling device (103) comprises: - a basic body (105), - a number of coolant channels formed in the base body (105) for guiding coolant through the base body (107), - an interface (109) for directing coolant through the coolant channels (107), and - a number of air guide elements (111, 121, 123, 125, 127) formed on a surface of the base body (105) wherein the cooling device (103) overlaps a winding head (113) of the stator in an area between the winding head (113) and the casing (115) around the stator (101) at least at the end face.

Description

[0001] The presented invention relates to an air compressor for conveying air, a manufacturing method for a cooling device for a stator of an air compressor, a cooling device for an air compressor and a fuel cell system according to the appended claims. State of the art

[0002] Air compressors for conveying air are usually designed as auxiliary units in a particularly compact manner for reasons of installation space.

[0003] Due to the compact design, thermal problems arise particularly in the area of ​​the stator of an electrical machine for driving an air compressor. Disclosure of the invention

[0004] Within the scope of the invention presented, an air compressor for conveying air, a manufacturing method for a cooling device for a stator of an air compressor, a cooling device for an air compressor, and a fuel cell system are presented. Further features and details of the invention emerge from the respective subclaims, the description, and the drawings. Features and details described in connection with the air compressor according to the invention naturally also apply in connection with the manufacturing method according to the invention, the cooling device according to the invention, and the fuel cell system according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is or can always be made reciprocally.

[0005] The invention presented serves in particular to provide a possibility for robust operation of an air-conducting system, in particular a fuel cell system.

[0006] Thus, according to a first aspect of the invention presented, an air compressor for conveying air is presented.

[0007] The presented air compressor comprises a stator, a cooling device and a shell surrounding the stator.

[0008] The cooling device of the air compressor comprises a base body, a number of coolant channels formed in the base body for conducting coolant through the base body and an interface for conducting coolant through the coolant channels and a number of air guiding elements formed on a surface of the base body, wherein the cooling device overlies a winding head of the stator in a region between the winding head and the shell around the stator at least on the front side.

[0009] In the context of the invention presented, an end face is understood to be a short side of a cylindrical stator.

[0010] The invention presented is based on a cooling device that is arranged in a region between the winding head of the stator of the air compressor presented and a stator casing, and that overlaps the stator at least at its front end. This means that the cooling device extends, in particular, over the entire length of the front end of the winding head, so that the winding head is cooled by the cooling device at least at its front end.

[0011] Due to the arrangement of the cooling device between the winding head and the stator shell, the air compressor presented can be designed to be particularly compact.

[0012] To cool the stator or the winding head, the cooling device comprises, on the one hand, a number of coolant channels through which a liquid, in particular coolant, can flow. On the other hand, the cooling device comprises air guiding elements for directing an air mass flow along or through the cooling device.

[0013] Accordingly, the cooling device of the presented air compressor is configured to direct two different fluid flows, namely a liquid mass flow of, for example, coolant, and an air mass flow. The liquid mass flow can cool the air mass flow on its path along the air guide elements by transferring heat from the air mass flow to the liquid mass flow through the base body of the cooling device. The heat is then transported by the liquid mass flow, for example, to a radiator, and ultimately released into the environment through the radiator.

[0014] It has been shown that an air mass flow is particularly advantageous for cooling a stator, in particular a winding head, since an air mass flow penetrates into all the spaces in the winding head and thus cools all of its surfaces.

[0015] The liquid flowing through the cooling device can, for example, be coolant from a cooling circuit of a system supplied with air by the air compressor, in particular a fuel cell system, so that the heat is transferred from the winding head or the air compressor into the fuel cell system and released to the environment, for example via a radiator of the fuel cell system.

[0016] For example, an air mass flow that is guided through the air guide elements can be branched off from a main air mass flow provided by a turbine of the air compressor, so that the air compressor is cooled more effectively, for example, dynamically as the load and turbine speed increase accordingly.

[0017] For example, an air mass flow that is guided through the air guide elements can be branched off from a main air mass flow provided by the compressor of the air compressor and optionally previously cooled, so that the air compressor is cooled more dynamically, for example, with increasing load and correspondingly increasing speed.

[0018] An interface for fluid-conducting connection to a cooling circuit can, for example, comprise an inlet and an outlet that can be fluid-tightly connected to an inlet and an outlet of the cooling circuit. For this purpose, the interface can, for example, have corresponding flanges that are fluidly coupled to the channels of the cooling device.

[0019] It can further be provided that the cooling device overlays the winding head at least in part, both at the front and laterally in the direction of the respective stator slots of the stator.

[0020] By superimposing the winding head on the front and sides by the cooling device, a surface for transferring thermal energy from the winding head to a fluid flowing in the cooling device is maximized and the winding head is protected from mechanical stress on the front and sides by the cooling device.

[0021] It can further be provided that the base body of the cooling device consists of a material whose thermal conductivity is higher than the thermal conductivity of air and whose electrical conductivity is less than 1% of the electrical conductivity of aluminum.

[0022] A high thermal conductivity of the base body of the cooling device results in a high heat transfer from the winding head to fluids flowing through the cooling device and a correspondingly good cooling effect or high cooling performance.

[0023] An electrical conductivity of the base body that is less than 1% of the electrical conductivity of aluminum suppresses eddy currents between the stator shell and the stator, thus maximizing the performance of the air compressor.

[0024] It can also be provided that the base body of the cooling device consists entirely or partially of ceramic.

[0025] Ceramics such as Al203 with a thermal conductivity of 20W / mK or AlN with a thermal conductivity of 170W / mK have proven to be particularly advantageous for dissipating heat from a winding head and are electrically insulating.

[0026] It can further be provided that additional air guiding elements are formed on the shell around the stator, which, together with the air guiding elements formed on the surface of the base body, form an air guiding path.

[0027] Air guide elements, such as projections, recesses, indentations, curves, fins, or any other aerodynamic element, define a path along which an air mass flow flows through the cooling device or along the base body of the cooling device. The air guide elements can be arranged such that the air mass flow flows, at least in some areas, parallel to a coolant flow flowing through the coolant channels, allowing for effective heat transfer from the air mass flow to the coolant flow.

[0028] It can further be provided that the air guiding elements formed on the surface of the base body comprise a number of cooling fins.

[0029] Cooling fins have proven to be particularly suitable for heat transfer due to their large surface area, so that, depending on their position, they can transfer heat from an air mass flow to a coolant flow or heat from the stator to the base body.

[0030] It can further be provided that the air guiding elements formed on the surface of the base body form a pin-fin structure.

[0031] A pin-fin structure has a particularly large surface area, which results in particularly good heat transfer between the base body and the respective air mass flow.

[0032] It can further be provided that recesses are made in the casing around the stator, into which the air guiding elements formed on the surface of the base body engage at least in some areas.

[0033] Through an interaction between the air guide elements and the shell around the stator, the shell forces an air mass flow into the air guide elements.

[0034] It can further be provided that the interface is configured for fluid-conducting connection with a cooling circuit.

[0035] It can further be provided that the air guiding elements formed on the surface of the base body consist of at least one material from the following list of materials: silicone, thermoplastic and duroplastic.

[0036] A base body made of silicone, thermoplastic or thermoset is particularly cost-effective, precisely formable and electrically insulating.

[0037] It can further be provided that a first cooling device is arranged at a first front end of the stator and a second cooling device is arranged at a second front end of the stator opposite the first end.

[0038] Two cooling devices at each end of the stator provide a particularly high cooling capacity to temper the stator, so that it can be subjected to a particularly high power.

[0039] According to a second aspect, the presented invention relates to a manufacturing method for a cooling device for a stator of an air compressor.

[0040] The proposed manufacturing method comprises providing a first part in which channels for conducting fluid are formed, providing a second part configured to overlie the first part, and connecting the first part and the second part.

[0041] By manufacturing a cooling device in two parts, the respective channels can be particularly easily incorporated into a first part, for example, by molding the first part with channels or by inserting the channels into the first part after an injection molding process to produce the first part, for example, by milling them. By subsequently arranging the second part on the first part, the channels formed in the first part are closed.

[0042] According to a third aspect, the presented invention relates to a cooling device for a possible embodiment of the presented air compressor.

[0043] The cooling device presented comprises a base body, a number of coolant channels formed in the base body for conducting coolant through the base body, an interface for conducting coolant through the coolant channels, and a number of air guiding elements formed on a surface of the base body, wherein the cooling device is configured to overlay a winding head of a stator of the air compressor in a region between the winding head and a shell around the stator at least on the front side.

[0044] According to a fourth aspect, the presented invention relates to a fuel cell system for converting energy.

[0045] The presented fuel cell system comprises a fuel cell stack and a possible design of the presented air compressor for supplying the fuel cell stack with air.

[0046] It can be provided that the cooling device of the air compressor is fluidly coupled to a cooling system of the fuel cell system.

[0047] All disclosures and advantages described above and below with respect to one aspect of the present disclosure apply equally to all other aspects of the present disclosure.

[0048] Further advantages, features, and details of the invention will become apparent from the following description, which describes exemplary embodiments of the invention in detail with reference to the drawings. The features mentioned in the claims and in the description may be essential to the invention individually or in any combination.

[0049] They show: Fig. 1 a schematic representation of a possible embodiment of the presented air compressor with a possible embodiment of the presented cooling device in a sectional side view, Fig. 2 further possible designs of the presented air compressor, Fig. 3 a possible design of the presented manufacturing process, Fig. 4 a possible design of the presented fuel cell system.

[0050] In Fig. 1 shows an air compressor 100 for conveying air. The air compressor 100 includes a stator 101, a cooling device 103, and a casing 115 surrounding the stator 101.

[0051] The cooling device 103 comprises a base body 105, a number of coolant channels 107 formed in the base body 105 for conducting coolant through the base body 105, an interface 109 for conducting coolant through the coolant channels 107, and a number of air guide elements 111 formed on a surface of the base body 105.

[0052] In the present case, the cooling device 103 overlaps a winding head 113 of the stator 101 in a region between the winding head 113 and the casing 115, both at the front and at the sides. For this purpose, the cooling device extends at an angle with a first front part 117 and a second lateral part 119, which extends in particular in an interior region of the stator 101. Of course, a second lateral part 119 extending on an outer side of the stator 101 is also possible.

[0053] The air guiding elements 111, together with the casing 115, form an air guiding path for guiding an air mass flow to the winding head 113, so that the winding head is flowed around by the air mass flow, heat is transferred from the winding head to the air mass flow, heat is transferred from the air mass flow to the base body 105, and coolant is transferred from the base body 105 to coolant flowing in the coolant channels 107.

[0054] In Fig. 2, air guiding elements 121 are shown, which cause a varying cross-section in the air guiding path between the shell 115 and the base body 105.

[0055] Furthermore, air guiding elements 123 are shown, which are designed as cooling fins.

[0056] Air guiding elements 125 determine a spatial geometry of an air mass flow that is guided around the air guiding elements 125.

[0057] Air guiding elements 127 comprise pin-fin structures formed on both the front and sides of the stator 101.

[0058] In Fig. 3 shows a manufacturing method 200 for a cooling device for a stator of an air compressor.

[0059] The manufacturing method 200 comprises a first provision step 201 in which a first part in which channels for conducting fluid are formed is provided, for example by an injection molding process, a second provision step 203 in which a second part which is configured to overlay the first part is provided, for example by an injection molding process, and a connecting step 205 in which the first part and the second part are connected, ie, for example, welded or glued.

[0060] In Fig. 4 shows a fuel cell system 300 for converting energy.

[0061] The fuel cell system 300 comprises a fuel cell stack 301 and an air compressor 100 according to Fig. 1 for supplying the fuel cell stack 301 with air.

[0062] The air compressor 100 is thermally coupled via an interface 303 to a cooling circuit 305 of the fuel cell system 300 for cooling the fuel cell stack 301.

Claims

[1] Air compressor (100) for conveying air, the air compressor (100) comprising: - a stator (101), - a cooling device (103) and - a sheath (115) surrounding the stator (101), wherein the cooling device (103) comprises: - a base body (105), - a number of coolant channels formed in the base body (105) for conducting coolant through the base body (107), - an interface (109) for conducting coolant through the coolant channels (107), and - a number of air guiding elements (111, 121, 123, 125, 127) formed on a surface of the base body (105) wherein the cooling device (103) overlies a winding head (113) of the stator in a region between the winding head (113) and the sleeve (115) around the stator (101) at least on the front side. [2] Air compressor (100) according to claim 1, characterized bythat the cooling device (103) overlies the winding head (113) both at the front and laterally in the direction of the respective stator slots of the stator (101) at least in some areas. [3] Air compressor (100) according to claim 1 or 2, characterized by that additional air guiding elements are formed on the casing (115) around the stator (101), which, together with the air guiding elements (111, 121, 123, 125, 127) formed on the surface of the base body (105), form an air guiding path. [4] Air compressor (100) according to one of the preceding claims, characterized by that the air guiding elements (111, 121, 123, 125, 127) formed on the surface of the base body (105) comprise a number of cooling fins. [5] Air compressor (100) according to one of the preceding claims, characterized by that the air guiding elements (111, 121, 123, 125, 127) formed on the surface of the base body (105) form a pin-fin structure. [6] Air compressor (100) according to one of the preceding claims, characterized by , in the casing (115) around the stator recesses are made into which the air guiding elements (111, 121, 123, 125, 127) formed on the surface of the base body (105) engage at least in some areas. [7] Air compressor (100) according to one of the preceding claims, characterized by that the air guiding elements (111, 121, 123, 125, 127) formed on the surface of the base body (105) consist of at least one material from the following list of materials: silicone, thermoplastic and duroplastic. [8] Air compressor (100) according to one of the preceding claims, characterized by that the interface (109) is configured for fluid-conducting connection to a cooling circuit (305). [9] Air compressor (100) according to one of the preceding claims, characterized bythat a first cooling device (103) is arranged at a first front end of the stator (101) and a second cooling device (103) is arranged at a second front end of the stator (101) opposite the first end. [10] Manufacturing method (200) for a cooling device (103) for a stator (101) of an air compressor (100), the manufacturing method (200) comprising: - providing (201) a first part in which channels (107) for conducting fluid are formed, - providing (203) a second part configured to overlay the first part, - Connecting (205) the first part and the second part. [11] Cooling device (103) for an air compressor (100) according to one of claims 1 to 9, wherein the cooling device (103) comprises: - a base body (105), - a number of coolant channels (107) formed in the base body (105) for conducting coolant through the base body (105), - an interface (109) for conducting coolant through the coolant channels (107) and - a number of air guiding elements (111, 121, 123, 125, 127) formed on a surface of the base body (105), wherein the cooling device (103) is configured to overlay a winding head (113) of a stator (101) of the air compressor (100) in a region between the winding head (113) and a shell (115) around the stator (101), at least on the front side. [12] Fuel cell system (300) for converting energy, the fuel cell system (300) comprising: - a fuel cell stack (301), - an air compressor (100) according to one of claims 1 to 9 for supplying the fuel cell stack (301) with air. [13] Fuel cell system (300) according to claim 12, characterized bythat the cooling device (103) of the air compressor (100) is fluidly coupled to a cooling system of the fuel cell system (300).

Images