WO2017045877A1

WO2017045877A1 - Battery housing with incorporated cooling

Info

Publication number: WO2017045877A1
Application number: PCT/EP2016/069920
Authority: WO
Inventors: Karsten Küper; Aaron Breitkopf; Carsten Wesche
Original assignee: Volkswagen Aktiengesellschaft
Priority date: 2015-09-17
Filing date: 2016-08-24
Publication date: 2017-03-23
Also published as: CN108028325A; DE102015217810A1

Abstract

The invention proposes, amongst other things, a housing (4') for a battery (3), in particular a high-voltage battery (3), for holding cell modules (8) and/or battery cells (9), at least having a housing base (5) and also a housing wall (6), wherein at least one section of said housing (4') comprises a cast part (12'). The cast part (12') advantageously has a channel structure (14) which is open as seen in cross section and which is formed by at least one elongate groove-like recess (15), wherein the groove-like recess (15) is covered by means of at least one covering element (16) in such a way that a channel structure (17), which is closed as seen in cross section, is designed to guide a temperature-control means within said channel structure.

Description

description

BATTERY HOUSING WITH BUILT-IN COOLING

The invention relates to a housing for a battery according to the preamble of patent claim 1 of the invention. According to claim 8 of the invention further relates to a vehicle with at least one, such a housing having battery. Finally, the concerns

Invention according to the preamble of claim 9, a method for producing said housing.

Electric or hybrid vehicles are powered by a rechargeable battery system,

in particular HV battery system (high-voltage battery system) with, for example, lithium-ion batteries operated. During driving of the vehicle as well as in the loading phase of such

Battery systems is registered by electrical power loss in live components heat in the battery system, which can lead to high thermal load on the batteries. By operating the battery at high cell temperatures is known to accelerate aging of the battery cells recorded, which with a shortened

Life of the battery system is associated. In extreme cases, too high a

Cell temperature for so-called burn through the battery cells and thus lead to a defect of the battery system. To counter this disadvantageous circumstance, can

for example, when exceeding a battery operating limit temperature a

native power reduction can be provided. Moreover, it is known when heating the battery cells of the battery system, the heat from the battery cells

dissipate by active, coolant-dependent cooling devices in the form of coolant flowed through cooling plates in the battery system respectively in a battery cells

receiving battery housing are installed (eg, DE 10 2008 059 947 A1,

DE 10 2008 059 969 A1). The cooling devices are in a cooling circuit one

Integrated air conditioning system of the vehicle. By the arrangement of the coolant flowed through cooling plates and associated coolant lines in the battery case are recorded an increased weight of the battery system and an increased risk of leakage in terms of coupling points of the coolant lines. Furthermore, this results in increased component costs. From practice, it is also known, coolant or heat conduction flowed through

Insert heat exchanger plates as a wall of the battery case, whereby the above-described cooling plates can be dispensable. Thus, US 2010/0151300 A1 describes a battery housing, in the wall of which at least one tubular cavity is provided, which in turn is filled with a heat conducting fluid and integrated into a fluid circuit in order to be able to operate the battery in a specific temperature range. That is, the battery should be both cooled and heated. DE 10 2013 210 932 A1 further describes a battery housing for accommodating battery cells, the wall of which has a channel for receiving a tempering means for cooling or heating the battery cells as required. As said cavity or channel was introduced into the wall of the battery housing or was formed within the same, about the documents US 2010/0151300 A1 and DE 10 2013 210 932 A1 are silent about. From DE 10 2008 059 967 B4 a heat conducting plate for a battery is known, which

Heat conducting plate is formed by a casting of a thermally conductive, preferably metallic material. In said casting a coolant leading, for example, a refrigerant of a vehicle air conditioning leading cooling coil or a cooling tube of a heat-conducting material is cast with a meandering course. The said heat-conducting plate forms a bottom plate of the battery.

The object of the invention is to provide an alternative with respect to the prior art housing for a battery with a heat conducting channel structure for temperature control of disposed within the housing or can be arranged cell modules and / or battery cells, which housing in particular easier and less expensive to produce , The object of the invention is also to provide a vehicle with at least one, such a housing having battery. Finally, it is an object of the invention to provide a method for producing said housing.

Starting from a housing for a battery, in particular high-voltage battery, for

Mounting of cell modules and / or battery cells, comprising at least a housing bottom and a housing wall, wherein at least a portion of said housing comprises a casting, this object is achieved in that the casting has an open in cross-section channel structure, the is formed by at least one elongated groove-shaped recess, wherein the groove-shaped recess means

at least one covering element is covered such that a channel structure, which is closed when viewed in cross-section, is designed to guide a tempering means within the same.

This solution has in terms of battery housing or portions thereof according to the prior art, which is a cast Wärmeleitplatte with cast cooling or

cast-in cooling tube favor (DE 10 2008 059 967 B4) many advantages. So must one cast tube made of a material which has a higher melting point than the material of said heat conducting plate or of the heat conducting plate having housing. If, for example, a steel pipe is cast into a battery housing made of aluminum or an aluminum alloy, there is a risk that disadvantageous air pockets will form between the two and / or that contact corrosion will occur. Furthermore, the bending radii of tubes are limited, so that any required narrow radii in the channel structure are not feasible. The geometric degrees of freedom are thus

limited, which may have the consequence that additional connections for the supply and removal of the temperature control are required, which in turn lead to a higher weight and a higher leakage risk of the battery system. In contrast, the design of the channel structure in the housing according to the invention is freely selectable, since the casting of the initially open in cross-section channel structure allows high geometric degrees of freedom. With a significant reduction in the number of parts and also the risk of leakage, a largely arbitrary course of the channel structure can be reproduced in the casting process. Furthermore, it should be noted that the wall thickness of a battery case with, for example, a

cast steel pipe is higher than in the channel structure of the housing according to the invention, since in addition to the pipe wall thickness with, for example 1 mm, due to the casting process in addition to the pipe 3 to 5 mm material of the cast housing must be present. This results in relation to the battery case in question, a higher weight.

At the same time, the efficiency of the Temperierungssystems according to the above-described prior art is worse, since the heat both when cooling and when heating the battery cells or cell modules a greater distance through the casting material, such as

For example, aluminum, must cover. The steel tube also has a lower thermal conductivity than aluminum. In contrast to the channel structure of the housing designed according to the invention, the overall heat transfer coefficient is lower, which may necessitate additional pipelines and / or larger pipe cross sections. In addition, it may be necessary according to the prior art, depending on the temperature, to use colder or warmer tempering, resulting in increased energy requirements. In contrast, in a channel structure of the housing according to the invention, the spacing between adjacent channels is minimized, resulting in material, weight and cost savings with increased Temperierungseffizienz.

The subclaims describe preferred developments or refinements of the invention. Thereafter, the at least one casting and / or the at least one cover element consists of a thermally conductive material. In this case, at least the part of the housing preferably consists of said thermally conductive material which is in thermally conductive contact directly or indirectly via any provided thermal contacting means with the cell modules and / or battery cells.

More preferably, the at least one casting and / or the at least one

Covering of a metal material, such as aluminum or an aluminum alloy, since aluminum due to its particularly good

Heat conduction properties advantageously supports the heat exchange between the cell modules and / or battery cells and the temperature control.

Preferably, the at least one cover element is fluid-tightly connected to the at least one cast part by means of material connection, in particular by gluing or welding, whereby leaks are effectively avoided. As a particularly advantageous joining method has in the case, both joining partners are made of a metal material, such as

Aluminum, the friction stir proved. The friction stir welding process is characterized in that a rotating tool with a largely wear-resistant

Welding pin is used, which welding pin is partially on the workpiece surface and partly in the workpiece during the joining. Due to the relative movement of the

Tool to the workpiece friction heat is generated, which leads to process temperature increase and thus the reduction of yield stress in the workpiece material to be joined. By a simultaneous rotation and advancing movement of the tool

Welded joints achieved along a definable joint line.

As already indicated above, the at least one cover element may form an outer or an inner contour of the housing or a portion of said outer or inner contour of the housing, whereby the battery cells either on the casting or on

Covering abut, depending on which side of the casting, the open channel structure formed and accordingly the cover is arranged. It is thus possible to produce one of the two joining partners also from a non-metallic and / or non-heat-conducting material, for example from a plastic, whereas, however, the joining partner, which is in contact with the cell modules and / or battery cells, in any case of a thermally conductive material, preferably of a metal material, such as aluminum is to be formed. In a further development of the invention, the formed closed channel structure is advantageously designed such that, with respect to the intended temperature control of the cell modules and / or battery cells, a series or parallel connection thereof is effected as required.

As already stated above, with regard to the prior art, geometric

Restrictions on the design of the channel structure in the housing according to the invention not recorded.

Advantageously, the formed closed channel structure is integrated in a tempering means circuit of an air conditioning system of a vehicle, in particular a motor vehicle.

The invention also relates to a vehicle, in particular electric or hybrid vehicle, with at least one, such a housing having battery.

The method for producing a housing for a battery, in particular a high-voltage battery, for holding cell modules and / or battery cells, wherein the housing has at least a housing bottom and a housing wall, is characterized by the following steps:

a) providing a casting, which comprises at least a portion of said housing, wherein the casting has an open in cross-section channel structure, which is formed by at least one elongated groove-shaped recess, and b) covering the at least one groove-shaped recess by means of at least one

Covering element such that a channel structure closed in cross-section to guide a tempering means is formed within the same.

In a development of the method, with regard to step a), a cast part is provided, which, in the form of a trough, comprises both the housing base and the housing wall in one piece. This measure advantageously reduces the material and assembly costs.

The invention will be explained in more detail with reference to an embodiment schematically illustrated in the drawings. However, it is not limited to this, but covers all embodiments defined by the claims. Show it:

Fig. 1 shows very schematically a motor vehicle, which is equipped with a battery, Fig. 2 is a sectional view of acting as a housing bottom of the battery Heat conducting plate according to the prior art,

Fig. 3 is an exploded perspective view of an inventively designed

Battery housing,

Fig. 4 is a sectional view of a housing bottom of the battery housing of FIG. 3, Fig. 5 a casting essential part of the said housing bottom according to a first invention

Variant embodiment, and

Fig. 6, the invention essential casting of said housing bottom according to a

second embodiment.

Fig. 1 shows first a vehicle 1, in this case motor vehicle, with an electric motor 2 as a drive motor and with a traction battery forming battery 3. According to this embodiment, therefore, is a purely electrically powered motor vehicle 1. By the invention is also included a so-called Hybrid vehicle, which in addition to one or more electric motors 2 also has an internal combustion engine (not shown in the drawing). The battery 3 has a housing 4, which is formed by a housing bottom 5, a housing wall 6 and a housing cover 7. The housing 4 is formed substantially cuboid. Within the housing 4 cell modules 8 shown in Fig. 3 are arranged and electrically interconnected. The cell modules 8 are in turn composed of individual battery cells 9. The cell modules 8 are supported on the housing bottom 5 and by means of mechanical fastening elements 10, in particular by means of

Screwing, attached to the same. The cell modules 8 and battery cells 9 are directly or as in the present case indirectly via a thermal contacting means 1 1 with the housing bottom 5 in contact. As can be seen from FIG. 3, the thermal contacting means 11 may be formed by a foil which conducts heat particularly well, for example metal foil, by a thermal compound or the like.

Fig. 2 shows a housing bottom 5 and a bottom plate of a generic battery case 4 according to the prior art, which by a so-called

Heat conducting plate is formed. Said heat conducting plate is formed by a casting 12 made of a thermally conductive, preferably metallic material. In said casting 12 is a refrigerant of a vehicle air conditioning leading cooling tube 13 cast from a heat-conducting material with a meandering curve not shown in the drawing. The disadvantages of such a trained thermally conductive plate are discussed in detail in the introduction.

Fig. 3 shows an inventively designed battery housing 4 ^' , which also includes a casting 12 ^' . The casting 12 ^' according to this embodiment consists of a thermally conductive, metal material, preferably made of aluminum or a

Aluminum alloy. This housing 4 ^' differs from the housing 4 according to the prior art, in particular in that the casting 12 ^' initially has a cross-sectionally open channel structure 14, which is formed by at least one elongate, nutenformige recess 15 (see. 5 and 6). Said nutenformige recess 15 is preferably already during the production of the casting 12 ^' according to a known casting method, such as a die-cast, chill casting or

Sand casting process, formed in the casting 12 ^' . The nutenformige recess 15 has merely exemplifying a semi-circular cross-section, which can be easily and inexpensively formed during said casting process. However, the invention is not limited to this specific cross-section, but covers any suitable and unilaterally open cross-section. Thus, said cross section can also simulate a polygon (not shown in the drawing). The invention is not limited to the preferred

Manufacturing method, but also detects a method in which the channel structure 14 or recess / s 15 after creation of the casting 12 ^', for example, in the cutting

Casting 12 ^' is / are formed.

According to this embodiment, the casting 12 ^', so to speak in one piece, both the housing bottom 5 and the housing wall 6 and is thus formed trough-shaped. The initially open channel structure 14 is on the the interior of the housing 4 ^'

opposite side of the housing bottom 5 is formed.

Said channel structure 14 is provided on the basis of the prior art to temper the cell modules 8 or battery cells 9 with the aid of tempering means. For this purpose, it is necessary to close the still open cross-section of the open channel structure 14. According to the invention, this is done by means of at least one presently plate-shaped cover member 16, respectively, a cover plate. The cover 16 is also made according to this embodiment of a thermally conductive, metal material, in particular aluminum or an aluminum alloy. By virtue of this measure, a channel structure 17, closed in cross-section, for guiding the tempering means is formed within the same, in order to cool or heat the cell modules 8 or battery cells 9 as required (see in particular FIG. 4).

With regard to the application of the battery 3 as a traction battery of a vehicle 1 or motor vehicle, the formed closed channel structure 17 in a not shown diagrammatically Temperierungsmittel circuit of an air conditioning system of the vehicle. 1 involved. For this purpose, the channel structure 17 has one, two or more inlets and outlets 18, 19. The said inlets and outlets 18, 19 can, as shown in FIGS. 5 and 6 in the

Casting 12 may be formed or provided by the cover 16 (not

shown in the drawing). The tempering agent is preferably a fluid, in particular a gas, such as carbon dioxide, a gas mixture, such as air, a liquid, such as oil, or a

Liquid mixture of, for example, water and ethylene glycol.

The fluid-tight connection between the casting 12 ^' and the cover 16 is / is preferably effected by material bond, in particular gluing or welding. As already stated above, in the case where both joining partners are made of a metal material, such as aluminum or an aluminum alloy, friction stir welding has proved to be particularly advantageous.

5 and 6 show in this respect joining regions 20 on the casting 12 ^' immediately adjacent to the open channel structure (s) 14 or of the ultimately resulting closed channel structure (s) 17. For better identification, said joining regions 20 were inserted into the Fig. 5 and 6 provided with a crossing hatching. The result of this is that the cover element 16 does not have to cover the entire surface of the casting 12, but can also be dimensioned such that only the said joining regions 20 are detected immediately adjacent to the channel structure (s) 14 and 17, respectively. The cover member 16 may accordingly have smaller dimensions than the housing bottom 5, from which material and weight savings can result.

It has been found that in comparative consideration of the state of the art with the inventive solution in question, the wall thickness of the housing 12 constructed as a cast part 12 and forming the housing bottom 5, the heat conducting plate of the prior art (FIG ) is greater than the wall thickness "s ₂ " of the housing bottom 5 of the housing 4 ^' according to the invention (FIG. 4) .The wall thickness "s" according to the prior art is 15 mm (FIG. 2) and results from 5 each mm casting material on both sides of the cooling tube 13, of 1 mm tube wall and of an inner diameter of the cooling tube 13. By contrast, the housing bottom 5 of the housing 4 ^' according to the invention with comparable tempering performance to the prior art, a wall thickness "s ₂ " of 12 mm auf, which results from only arranged on one side of the open channel structure 14 casting material of 4 mm above the present in cross-section semicircular nutenformigen Au Suction 15, from a radius of the groove-shaped recess 15 of 6 mm and a material thickness of the cover 16 and cover plate of 2 mm. D. h., According to the state of Technique is far more the cooling tubes 13 enclosing casting material required than in the channel structure 14, 17 according to the invention.

In addition to the material and weight savings, the solution according to the invention also opens up space-saving advantages with regard to the state of the art. These result in particular from the fact that when using embedded in the casting 12 cooling tubes 13 and in particular when meandering arrangement of the same in the casting 12 a limit to the formation of minimum radii is recorded. Such a restriction is not to be noted with regard to the housing 4 ^' according to the invention with the channel structure 14, 17 integrally formed in the casting 12 ^' .

FIGS. 5 and 6 show by way of example two variants of the embodiment of the open

Channel structure 14 of the casting 12 ^'of the housing bottom 5. Thus, FIG. 5 is a channel structure 14, which after closing and feeding the same so to speak, a series circuit of the to be tempered cell modules 8 or battery cells 9 maps to tempering by the present two consecutive channels in Form of groove-shaped recesses 15 are formed, which meandering arranged each extending from the inlet 18 to the outlet 19, whereby a temperature of the cell modules 8 in series one after the other is effected. The series-connected cooling system operates according to this embodiment, the mating principle in order to achieve a good homogeneity of the housing temperature. That is, there are thus two circuits created, which are flowed through in opposite directions (see.

Directional arrows). On average, this results in a homogeneous temperature distribution among the respective cell modules 8 without thereby obtaining a gradient due to already heated cooling medium.

In contrast, FIG. 6 shows a channel structure 14 which, as it were, depicts a parallel connection of the cell modules 8 or battery cells 9 to be tempered by first collecting channels 14a, 14b for both the inlet and the outlet 18, 19 between which each depending cell module 8 more, in accordance with this embodiment four each extending parallel to each other Temperierungskanäle 14c extend. This variant has the advantage that all cell modules 8 undergo a largely uniform temperature control.

According to this exemplary embodiment, the open channel structure 14 is formed on the side of the battery bottom 5 facing away from the interior of the housing 4 ^' and thus covered fluid-tight from outside by means of the cover element 16 to form the closed channel structure 17. However, the invention is not limited to this specific Embodiment, but also includes a non-illustrated

Embodiment in which the open channel structure 14 on the interior of the

Housing 4 ^' facing side of the battery bottom 5 is formed and thus covered to form the closed channel structure 17 from the inside by means of the cover 16 fluid-tight.

Furthermore, the channel structure 14 and 17 is not limited to the housing bottom 5, but may be provided both alone and in combination with the housing bottom 5 on the housing wall 6. In said combination, a further improved or more effective temperature control is possible. Here, 6 separate inlets and outlets 18, 19 may be provided for the housing bottom 5 and the housing wall, or the channel structures 14 and 17 are interconnected fluidically and have a common inlet and outlet 18, 19 (not shown in the drawing).

There is the possibility and is covered by the invention accordingly, to include the housing cover 7 in the said temperature. This is usually placed on the free end face 22 of the housing wall 6 and, if necessary with the aid of mechanical fasteners, such as screws, fluid-tight manner with the housing wall 6 by mediating a circumferential sealant 21, in particular a ring seal and / or an adhesive. If the housing cover 7 is also formed with a closed channel structure 17 according to the invention, this can

For example, at least be incorporated into the channel structure 17 of the housing wall 6. In contrast, the housing cover 7 with respect to its tempering function may also be self-sufficient and thus have its own inlet and outlet 18, 19 (not shown in the drawing).

The exemplary embodiment described above furthermore depicts a cast part 12 ^' , which is trough-shaped and integrally comprises both the housing bottom 5 and the housing wall 6. The housing base 5 can also be formed separately from the housing wall 6 or wall parts thereof and produced by a casting process. In this case, the housing bottom 5 is to be completed in a downstream mounting method with the housing wall 6. The cover 16 can be mounted before or after said completion of the relevant casting 12 ^' (not shown in the drawing). Moreover, the embodiment described above relies on a metal casting 12 ^' and a metallic cover member 16 fluidly connected thereto. As already stated above, the one cover element 16 may form an outer or an inner contour of the housing 4 ^' or a portion of said outer or inner contour of the housing 4 ^' , whereby the cell modules 8 or battery cells 9 either with the casting 4 ^' or with the cover 16 directly or indirectly via said

Contacting 1 1 are in a thermally conductive contact, depending on which side of the casting 12 ^'formed the open channel structure 14 and accordingly the

Cover 16 is arranged. This opens up the possibility of producing either the casting 12 ^' or the covering element 16 from a non-metallic and / or non-sufficiently thermally conductive material, for example a plastic, which is thus also covered by the invention. However, the joining partner, which is in heat-conducting contact with the cell modules 8 or battery cells 9, is in any case made of a thermally conductive material, in particular of a metal material, such as aluminum or an aluminum alloy.

A preferred embodiment (not shown) provides for arranging a plurality of batteries 3 within the vehicle 1 in such a way that the closed channel structure 17 lies between at least two batteries 3 and serves to control the temperature of the adjacent batteries 3 located on the closed channel structure 17.

LIST OF REFERENCE NUMBERS

vehicle

electric motor

battery

casing

' Casing

Housing bottom

Housing wall

Housing cover

cell module

battery cell

0 fastening element

1 contacting agent

2 castings

2 ^' casting

3 cooling tube

4 open channel structure

4a collecting channel

4b collecting channel

4c tempering channel

5 recess

6 cover element

7 closed channel structure

8 inlet

9 process

0 joining range

1 sealant

2 front side (housing wall 6)

Claims

claims

1. housing (4 ^' ) for a battery (3), in particular high-voltage battery (3), for holding cell modules (8) and / or battery cells (9), at least comprising a housing bottom (5) and a housing Wall (6), wherein at least a portion of said housing (4 ^' ) comprises a casting (12 ^' ), characterized in that the casting (12 ^' ) has a cross-sectionally open channel structure (14) through at least one elongated groove-shaped recess (15) is formed, wherein the groove-shaped recess (15) by means of at least one cover (16) is covered such that a closed in cross-section channel structure (17) for guiding a tempering means is formed within the same.

2. Housing (4 ^' ) according to claim 1, characterized in that the at least one

Cast part (12 ^' ) and / or the at least one cover element (16) from a

thermally conductive material.

3. housing (4 ^' ) according to claim 2, characterized in that the at least one

Cast part (12 ^' ) and / or the at least one cover (16) made of a metal material.

4. Housing (4 ^' ) according to claim 3, characterized in that the at least one cover element (16) with the at least one casting (12 ^' ) is fluid-tightly connected by material connection.

5. housing (4 ^' ) according to one of claims 1 to 4, characterized in that the at least one cover (16) has an outer or an inner contour of the housing (4 ^' ) or a portion of said outer or inner contour of the housing (4 ^' ) forms.

6. housing (4 ^' ) according to one of claims 1 to 5, characterized in that the formed closed channel structure (17) is designed such that with regard to the proper temperature of the cell modules (8) and / or battery cells (9) a Series or parallel circuit of the same effect.

7. Housing (4 ^' ) according to one of claims 1 to 6, characterized in that the formed closed channel structure (17) is incorporated in a Temperierungsmittel circuit of an air conditioning system of a vehicle (1).

8. vehicle (1), in particular electric or hybrid vehicle, with at least one, a

Housing (4 ^' ) according to one of claims 1 to 7 having battery (3).

9. A method for producing a housing (4 ^' ) for a battery (3), in particular

High-voltage battery (3), for holding cell modules (8) and / or battery cells (9), wherein the housing (4 ^' ) at least comprises a housing bottom (5) and a housing wall (6), characterized by the following Steps:

a) providing a casting (12 ^' ) which comprises at least a portion of said housing (4 ^' ), the casting (12 ^' ) having a cross-sectionally open channel structure (14) formed by at least one elongated groove-shaped recess (15 ) is formed, and

b) covering the at least one nutenformigen recess (15) by means of at least one cover (16) such that a cross-sectional closed channel structure (17) for guiding a tempering is formed within the same.

10. The method according to claim 9, characterized in that with regard to the step a), a casting (12 ^' ) is provided which trough-shaped both the

Housing bottom (5) and the housing wall (6) integrally includes.