WO2023099740A1

WO2023099740A1 - Battery housing, traction battery and method for producing a battery housing

Info

Publication number: WO2023099740A1
Application number: PCT/EP2022/084220
Authority: WO
Inventors: Fritz Wegener
Original assignee: Webasto SE
Priority date: 2021-12-02
Filing date: 2022-12-02
Publication date: 2023-06-08
Also published as: DE102021131785A1

Abstract

The invention relates to a battery housing (10) for an electric battery (1); an electric battery (10), in particular a traction battery for an electric or hybrid vehicle or a battery for a vehicle with a fuel cell; and a method for producing a battery housing (10) for an electric battery (1). The battery housing (10) comprises a wall system (11, 11a, 11b, 12) which defines a battery interior (13), the wall system (11, 11a, 11b, 12) having, on a side facing the battery interior (13), at least one portion of increased surface area (15), which is an integral constituent part of the wall system (11, 11a, 11b, 12).

Description

Battery case, traction battery and method of manufacturing a battery case

technical field

The present invention relates to a battery case for an electric battery, an electric battery, in particular a traction battery for an electric or hybrid vehicle or a battery for a vehicle with a fuel cell, and a method for producing a battery case.

State of the art

Battery systems for electric and hybrid vehicles as well as for vehicles with fuel cells are the subject of current research and development. The performance-related parameters of a battery system, such as lifetime and capacity, depend significantly on the application environment. The electrochemical processes taking place in the battery depend on the ambient temperature and humidity, for example, both when providing and delivering electrical power and when charging.

Creating and maintaining a well-defined, especially dry, environment for the battery cells is therefore important for reliable operation of a battery system. In addition, the battery cells and battery modules that make up the battery system must be protected from the ambient conditions. For these and other reasons, a battery housing is provided when constructing a battery system, which is set up to accommodate battery modules and to protect them from external influences.

Battery cases are typically constructed of steel or aluminum walls/covers. Since the ingress of moisture, for example in the form of water vapor, cannot be completely prevented during production and/or during operation, it can happen that condensation forms on the inside of the housing when there are temperature changes or temperature gradients.

To prevent the condensate from dripping into the battery and coming into contact with electrically conductive components, where it could cause short circuits or corrosion, for example, various methods are known for dehumidifying the battery. DE 10 2013218 700 A1 describes a Apparatus for dehumidifying a battery case, comprising a body having a plurality of capillaries and electrodes for generating an electric field to remove water through the capillary. Alternatively, the battery can be equipped with an insert made of an absorbent material, as described in DE 102020 119 727 A1, for example.

Both active dehumidification systems and passive solutions such as inserts, mats and the like require space and require additional design effort due to their installation and fixation in the battery. A wet insert can also lead to insulation problems, and problems resulting from air and creepage distances can be caused or exacerbated.

Presentation of the invention

One object of the invention is to provide an improved battery housing, an electric battery with such a housing and an improved method for producing a battery housing, in particular to improve dehumidification.

The object is achieved by a battery housing having the features of claim 1, an electric battery having the features of claim 7 and a method having the features of claim 11. Advantageous developments follow from the dependent claims, the following description of the invention and the description of preferred exemplary embodiments.

The battery housing according to the invention is used to build up and protect an electric battery, in particular a traction battery for an electric or hybrid vehicle or a battery for a vehicle with a fuel cell.

The battery housing comprises a wall defining a battery interior, the wall having at least one section with an enlarged surface area on the side facing the battery interior, which is an integral part of the wall.

The term "enlarged surface" is defined here relative to untreated surface sections of the wall of the battery housing. In other words, the increased surface area portions are characterized by increased surface area (per unit projected area) over other surface portions of the battery case, particularly over a normal surface finish of the material or base material of the battery case. Furthermore, the sections with increased surface area are an integral part of the wall. "Integral Part" means that the Sections with enlarged surface with the wall or its base material cannot be separated non-destructively within the scope of intended use.

The increase in surface area results in pores, crevices, depressions, and the like, allowing the one or more increased surface area portions to accommodate condensate without allowing it to drip or run off. The fact that the sections with an enlarged surface area are able to adsorb and possibly distribute water in pores, gaps, depressions etc. is thus used to dehumidify the battery, which counteracts the formation of drops. The moisture stored in this way can be released again through evaporation. Condensate development is avoided or at least reduced effectively and with little structural effort.

By making the increased surface area portions an integral part of the battery case, the case parts are available as finished products. Subsequent assembly or fixing is not required, which means that the structural effort and product costs can be minimized. In addition, the battery housing can be designed and manufactured in a particularly compact manner, which not only results in a maximization of the battery capacity per volume unit, but also minimizes the free internal volume of the battery. This in turn contributes effectively to fire protection.

The battery housing is preferably constructed in several parts, comprising a trough-like basic housing and a cover which closes the basic housing as a lid, the cover having at least one section with an enlarged surface area on the side facing the battery interior, which is an integral part of the cover. In this way, any condensation moisture is effectively prevented from dripping onto electrical battery components.

On the side facing the battery interior, the cover is preferably equipped essentially completely with an enlarged surface, which is an integral part of the cover, as a result of which protection against condensation is maximized without any additional construction work.

The section or sections with an enlarged surface is/are preferably produced by surface treatment of the wall, as a result of which no additional structural measures are required during assembly of the battery. as appropriate Surface treatments that come into consideration are, in particular, roughening, perforating, etching, coating, electroplating, anodizing and/or laser treatment.

The section or sections with an increased surface area are preferably produced by coating the wall with a coating material. The coating material differs from the base material of the wall (e.g. steel or aluminum), which allows the adsorption of moisture to the desired sections to be maximized. The coating material is preferably applied to the base material by means of a spraying process in order to simplify the production process. Porous materials, for example zeolite, basalt or pumice stone, can be used as the coating material. Substances such as fabric or fleece can also be used to produce the sections with an enlarged surface, provided they are an integral part of the battery housing, i.e. are inseparably connected to the basic material of the battery housing when used as intended.

Preferably, the increased surface area includes a plurality of small cavities such as pores, crevices or depressions to accommodate any condensate therein. The pores or cavities preferably have a dimension in the micrometer range.

The object mentioned above is also achieved by an electric battery with a battery housing according to one of the embodiment variants presented above. The battery is preferably a traction battery for an electric or hybrid vehicle or a battery for a fuel cell vehicle.

The features, technical effects, advantages and exemplary embodiments that have been described in relation to the battery housing apply analogously to the battery.

The battery usually has at least one battery module with at least one battery cell, the battery module being arranged in the battery housing. Several battery cells are usually combined to form a battery module. The battery cells are preferably cylindrical in shape and arranged in a grid-like manner next to one another, aligned in parallel, for example in the structure of closest circular packing (seen in cross-section relative to the longitudinal extension of the battery cells). Preferably, the battery comprises one or more electrical components, with the portion having an enlarged surface area being arranged in the area or in the vicinity of the electrical component(s). The terms "in the area", "nearby" etc. are defined here by the intended function, ie they require a positioning of the section or sections with an enlarged surface which prevents or at least reduces exposure of the relevant electrical components to condensation . Preferably, a portion of increased surface area is located above the electrical component(s). Spatial designations such as "above" etc. are defined by the intended installation position of the battery.

Preferably, the one or more electrical components include a battery management system and a moisture sensor in communication therewith, which are set up to determine the moisture load on the battery. In this way, when a critical threshold value is reached, the battery management system can, for example, switch the battery to a safe state and/or issue a corresponding warning or send it to an on-board system of the vehicle.

The above-mentioned object is also achieved by a method for producing a battery housing for an electric battery, the method having: providing a wall, preferably comprising a trough-like basic housing and a cover for closing the basic housing; incorporating at least a portion of increased surface area into the wall; and assembling the battery housing such that the wall defines a battery interior and the at least one increased surface area portion faces the battery interior.

The features, technical effects, advantages and exemplary embodiments that have been described in relation to the battery housing and the battery apply analogously to the method.

For the reasons mentioned above, the integration of the at least one section with an enlarged surface preferably includes a surface treatment of the wall, in particular a process of roughening, perforating, etching, coating, electroplating, anodizing and/or laser treatment.

Preferably, for the reasons given above, the integration of the at least one portion with an increased surface area comprises a process of coating the wall with a Coating material, wherein the coating material is particularly preferably applied to the wall by a spraying process.

The coating material is preferably a porous material, for example zeolite, basalt or pumice stone, or a fabric, for example woven or non-woven material, for the reasons mentioned above.

Further advantages and features of the present invention are evident from the following description of preferred exemplary embodiments. The features described therein can be implemented on their own or in combination with one or more of the features set out above, insofar as the features do not contradict one another. The following description of preferred exemplary embodiments is made with reference to the accompanying drawings.

Brief description of the figures

Preferred further embodiments of the invention are explained in more detail by the following description of the figures. show:

FIG. 1 shows a schematic view of a battery with a battery housing according to an exemplary embodiment; and

FIG. 2 shows a schematic view of a battery with a battery housing according to a further exemplary embodiment.

Detailed description of preferred embodiments

Preferred exemplary embodiments are described below with reference to the figures. Elements that are the same, similar or have the same effect are provided with identical reference symbols in the figures, and a repeated description of these elements is sometimes dispensed with in order to avoid redundancy.

FIG. 1 is a schematic view of a battery 1, which is preferably a traction battery for an electric or hybrid vehicle or a battery for a fuel cell vehicle.

The battery 1 has a battery housing 10, which is preferably designed to be fluid-tight or can be brought into a fluid-tight state for regular operation. The battery housing can be constructed in one piece or in several pieces. In the present embodiment, this includes Battery housing a trough-like base housing 11 with side walls 11 a and a bottom 11 b and a cover 12 which closes the base housing 11 as a lid.

The basic housing 11 and the cover 12 form a wall defining a battery interior 13 . The base material of the wall of the battery housing is, for example, steel, aluminum or another alloy, with the designation "base material" indicating that a combination of different materials is possible.

The battery 1 comprises at least one, but preferably a plurality of battery modules 20, which usually combine a plurality of battery cells 21. The battery cells 21 are preferably of cylindrical shape and are arranged in a grid-like manner next to one another, aligned in parallel, for example in the structure of the closest circular packing (seen in cross section to the longitudinal extension of the battery cells 21). The battery cells 21 are held in a sandwich-like manner by a module base plate 22 and a module cover plate 23, which, in addition to the mechanical function of combining and fixing the battery cells 21 into battery modules 20, can carry out the electrical wiring of the battery cells 21. However, the battery modules 20 can also be constructed in other ways.

The battery modules 20 may be arranged on a single level, as in the case of the embodiments of Figures 1 and 2, or on multiple levels. A geometrically less strict arrangement, for example a zigzag overlapping of the levels and/or columns of the battery modules 20, is also possible.

In addition to the battery modules 20, the battery 1 includes one or more electrical components 30, for example in the form of electrical lines, an electronic controller, microcontrollers, sensors, memory chips and the like. The electrical components 30 particularly preferably include a battery management system (BMS) 31. The BMS 31 usually has a communication interface to the vehicle and can thus (for example in real time) provide various information about the battery status.

The BMS 31 can determine the moisture load on the battery 1 in cooperation with a moisture sensor 32 . When a critical threshold value is reached, the BMS 31 can switch the battery 1 to a safe state and/or issue a corresponding warning or send it to an on-board system of the vehicle. In order to prevent condensate from developing on the inside of the battery housing 10, collecting and possibly running down and/or dripping, which can disrupt and damage critical areas of the battery 1, in particular electrical components 30, the battery housing 10 includes a on the inside or several sections with an enlarged surface 15. A complete or essentially complete equipment of the housing 10 with an enlarged surface 15 is also possible.

In the exemplary embodiment in FIG. 1, essentially the entire inside of the cover 12 is equipped with a section with an enlarged surface 15 . In the exemplary embodiment in FIG. 2, there are sections with an enlarged surface 15 in the area of electrical components 30 in order to concentrate protection against condensation on these areas. In particular, an enlarged surface area 15 is provided on the cover 12 above the electrical components 30 concerned. Alternatively or additionally, the side walls 11 closest to the electrical components 30 can be equipped with one or more sections with an enlarged surface 15 .

The sections with increased surface area 15 are characterized by an increased surface area (per unit projected area) compared to other surface sections of the battery case 10, in particular compared to a normal surface finish of the material or base material of the battery case 10. Furthermore, the sections with an enlarged surface 15 are an integral part of the wall of the battery housing 10. "Integral part" here means that the sections with an enlarged surface 15 cannot be separated from the wall, in particular from its base material, without being destroyed as part of the intended use.

The integral nature can be achieved by providing the enlarged surface portions 15 with a surface treatment such as roughening, perforating, etching, coating, electroplating, anodizing and/or laser treating. The sections with an enlarged surface 15 are particularly preferably produced by coating the relevant insides of the housing, for example by applying a coating material in a spraying process. Porous materials such as zeolite, basalt, pumice etc. can be considered as coating materials. Fabric, fleece or the like can also be used to produce the sections with an enlarged surface 15 if they are an integral part of the battery housing 10, ie are inseparably connected to the basic material of the battery housing 10 when used as intended. The sections with increased surface area 15 can absorb the condensate without it being able to drip or run off. The fact that the sections with an enlarged surface 15 are able to adsorb and possibly distribute water in pores, gaps, depressions, etc. is thus used for dehumidification, as a result of which the formation of drops is counteracted. The moisture stored in this way can be released again through evaporation. Condensate development is avoided or at least reduced effectively and with little structural effort.

With the increased surface area portions 15 being an integral part of the battery case 10, the case parts are available as finished products. Subsequent assembly or fixing is not required, which means that the structural effort and product costs can be minimized. In addition, the battery housing 10 can be designed and manufactured to be particularly compact, which not only results in a maximization of the battery capacity per volume unit, but also minimizes the free internal volume of the battery 1 . This in turn contributes effectively to fire protection.

As far as applicable, all individual features that are presented in the exemplary embodiments can be combined with one another and/or exchanged without departing from the scope of the invention.

Reference character list

1 battery

10 battery housing 11 basic housing

11a side wall

11b floor

12 cover

13 Battery interior 15 Section with enlarged surface

20 battery module

21 battery cell

22 module base plate

23 Module cover plate 30 Electrical component

31 battery management system

32 humidity sensor

Claims

Expectations

1. Battery case (10) for an electric battery (1) comprising a battery interior (13) defining wall (11, 11a, 11b, 12), wherein the wall (11, 11a, 11b, 12) on a the battery interior (13) side facing at least one section with an enlarged surface (15), which is an integral part of the wall (11, 11a, 11b, 12), has.

2. Battery housing (10) according to claim 1, characterized in that the battery housing (10) is constructed in several parts, comprising a trough-like base housing

(11) and a cover (12), which closes the basic housing (11) as a lid, the cover (12) on the side facing the battery interior (13) facing the at least one section with an enlarged surface (15), which is an integral part of the cover

(12) is.

3. Battery housing (10) according to claim 2, characterized in that the cover (12) on the battery interior (13) facing side substantially completely equipped with an enlarged surface (15), which is an integral part of the cover (12). is.

4. Battery housing (10) according to one of the preceding claims, characterized in that the at least one section with an enlarged surface (15) is produced by surface treatment of the wall (11, 11a, 11b, 12), preferably by roughening, perforating, Etching, plating, electroplating, anodizing and/or laser treating.

5. Battery housing (10) according to claim 4, characterized in that the at least one section with an enlarged surface (15) is produced by coating the wall (11, 11a, 11b, 12) with a coating material, preferably by a spraying process, wherein the coating material is a porous material, preferably zeolite, basalt or pumice, or a fabric, preferably woven or non-woven.

6. Battery housing (10) according to any one of the preceding claims, characterized in that the at least one section with an enlarged surface area (15) comprises a multiplicity of pores, gaps or depressions.

7. Electric battery (1) with a battery housing (10) according to any one of the preceding claims, wherein the battery (1) is preferably a traction battery for an electric or hybrid vehicle or a battery for a vehicle with fuel cells.

8. Electric battery (1) according to claim 7, characterized in that it comprises at least one battery module (30) with at least one battery cell (31), which is arranged in the battery housing (10).

9. Electric battery (1) according to claim 7 or 8, characterized in that it comprises one or more electrical components (30) and the at least one section with an enlarged surface (15) in the region of the electrical components (30), preferably above the electrical components (30) is arranged.

10. Electrical battery (1) according to claim 9, characterized in that the one or more electrical components (30) comprise a battery management system (31) and a moisture sensor (32) in communication therewith, which are set up to to determine the moisture load on the battery (1).

11 . Method for producing a battery housing (10) for an electric battery (1), the method comprising:

Providing a wall (11, 11a, 11b, 12), preferably comprising a trough-like base housing (11) and a cover (12) for closing the base housing (11);

Integrating at least one section with an enlarged surface (15) into the wall (11, 11a, 11b, 12); and

Assembling the battery housing (10) so that the wall (11, 11a, 11b, 12) defines a battery interior (13) and the at least one section with an enlarged surface (15) faces the battery interior (13).

12. The method according to claim 11, characterized in that the integration of the at least one section with an enlarged surface (15) involves a surface treatment of the wall (11, 11a, 11b, 12), preferably a process of roughening, perforating, etching, coating , electroplating, anodizing and/or laser treatment. Method according to Claim 12, characterized in that the integration of the at least one section with an enlarged surface (15) comprises a process of coating the wall (11, 11a, 11b, 12) with a coating material, the coating material preferably being applied by a spraying process the wall (11, 11a, 11b, 12) is applied. A method according to claim 13, characterized in that the coating material is a porous material, preferably zeolite, basalt or pumice, or a fabric, preferably woven or non-woven.