Mounting board for a traction battery for a motor vehicle, as well as traction battery and motor vehicle

Abstract

The invention relates to a mounting board (1) for a traction battery for a motor vehicle, a traction battery comprising the mounting board (1), and a motor vehicle comprising the traction battery. The mounting board (1) is configured to electrically isolate a cell shoulder of a cell pack of the traction battery from an electrically conductive cell contacting system of the traction battery. Furthermore, the mounting board (1) has a grid structure whose elongated struts (2) define material-free contact zones (3). A flow-facilitating element (6) is arranged on a lower side (4) of the struts (2) and / or on a higher side (5) of the struts (2), which is specifically configured to promote the flow of a pasty foam mass along the corresponding side (4, 5) of the struts (2).

Description

The present invention relates to a mounting board for a traction battery for a motor vehicle. The invention further relates to a traction battery having such a mounting board. The invention also relates to a motor vehicle having such a traction battery.A conventional traction battery includes battery cells, a mounting board, and a cell contacting system electrically interconnecting the battery cells. A conventional mounting board is known, for example, from DE 10 2013 020 369 A1 and is referred to there as a retaining plate. The mounting board electrically isolates the cell contacting system and the battery cells from one another-apart from locations where a respective pole of the battery cells and the cell contacting system are electrically conductively connected to one another as intended. Furthermore, it is known to foam an interior of the traction battery. For this purpose, for example, a liquid or pasty foam mass is introduced into a housing of the traction battery, after which the foam mass reacts to form a dimensionally stable foam body. As a result, the battery cells, the mounting board, and the cell contacting system are embedded in the foam body. The cell contact-making system and the mounting board are each planar structures and face one another parallel to one another in terms of their surface, so that a gap is formed between the cell contact-making system and the mounting board.It has been shown from internal investigations that in conventional traction batteries there may be an undefined failure of the foam body, in particular in regions in which the foam body should provide an adhesion connection between the mounting board and a further component of the traction battery, for example the cell contact system. This may result in damage to the relevant component and ultimately in a malfunction of the traction battery. It has been found by further investigations that the failure of the adhesion connection is made possible if the gap formed between the cell contact-making system and the mounting board is not completely filled with foam, which in turn leads to an uneven stress distribution and thus to a nondefinable failure chain.An object of the present invention is to increase a reliability of traction batteries.This object is achieved by the subject matters of the independent claims. Further possible embodiments of the invention are disclosed in the dependent claims, the description and the figures. Features, advantages and possible configurations which are set forth in the context of the description for one of the subjects of the independent claims are to be regarded, at least analogously, across all categories and embodiments as features, advantages and possible configurations of the respective subject of the other independent claims and of each possible combination of the subjects of the independent claims, optionally in conjunction with one or more of the dependent claims.According to the invention, a mounting board for a traction battery for a motor vehicle is proposed. In addition, the present invention also includes, as a respective further subject matter, a traction battery and a motor vehicle. The motor vehicle is a purely electrically or hybrid-electrically drivable motor vehicle which has the traction battery. The traction battery has the mounting board, a cell pack formed from battery cells and an electrically conductive cell contact-making system, which are embedded in a foam body. The cell contact-making system and the mounting board (which can also be referred to as a carrier plate) are each planar structures and face one another parallel to the surface. In this case, the mounting board is arranged between a cell shoulder side of the cell stack and the cell contact-making system, with the result that the cell shoulder side and the cell contact-making system are electrically insulated from one another by means of the mounting board. A gap is formed between the cell contact-making system and the mounting board. When producing the traction battery, a liquid or pasty foam mass is filled into a housing of the traction battery, after which the foam mass fully reacts to form a dimensionally stable foam body. As a result, the battery cells, the mounting board, and the cell contacting system are embedded in the foam body. Further elements or components of the traction battery are known to the person skilled in the art and therefore do not require any more detailed explanation; the traction battery is only discussed here insofar as it is necessary to illustrate the invention.The mounting board has a grid structure, the elongate struts of which delimit material-free contact-making zones. In particular, the battery cells are round cells which have their positive pole and their negative pole each on a common end face. An annular cell shoulder of the respective battery cell forms, for example, the negative pole, whereas a central region of the battery cell which is electrically insulated from the cell shoulder forms the positive pole. When the mounting board is placed on the cell shoulder side of the cell stack as intended, the respective positive pole is arranged completely and the respective negative pole is arranged at least partially in one of the contact zones. For the traction battery, the cell contact-making system extends through the contact-making zones and is electrically conductively connected to the poles of the battery cells.On an underside of the struts and / or on an upper side of the struts-i.e. on the entire upper / underside of the relevant strut or only on a partial region of the upper / underside-a flow-promoting means is arranged which is specifically configured to promote a flow of a pasty foam mass along the corresponding side of the struts. During the production of the traction battery, the foam mass travels / flows along the mounting board in an especially efficient manner while the traction battery is being filled with the foam mass and / or while the foam mass reacting to the foam body expands / foams. In particular, the foam compound reaches the gap formed between the mounting board and the cell contacting system in a particularly efficient manner. As a result, the gap is completely filled with the foam compound, so that a particularly reliable and stable adhesion connection is formed between the mounting board and the cell contacting system.Voids or foam-free regions between the mounting board and the cell contact-making system remain in an advantageous manner. On the upper and / or lower side of the respective strut, an adhesion connection promoting means can (optionally) be arranged, which is specifically configured to promote and / or reinforce the adhesion connection between the mounting board and the cell contacting system.In a further possible embodiment, it is provided that the flow-promoting means has a surface elevation or more of such surface elevations on the corresponding side of the struts, that is to say on the upper side thereof and / or on the lower side thereof. The respective surface elevation thus extends into the gap, so that a free or flow-through cross section of the gap is reduced. During foaming of the traction battery, the respective surface elevation is surrounded by the foam mass, so that it fills the gap particularly efficiently due to the narrowed cross section.According to a further possible embodiment, a direction of longitudinal extent of the surface elevation of the respective strut is directed at a strut central region. As a result, when filling the traction battery with the foam mass and / or when expanding the foam mass in the traction battery, a foam material front is advantageously directed into the central region of the struts, where the foam material front impinges, for example, on an approaching foam material front, as a result of which the foam material fronts flow into one another and unite.In a possible development, the surface elevation has one or more of the following structures: a corrugation structure; a tear structure, which is also referred to as a lens or corrugation structure; and a drop structure. Due to such a structure or due to a combination of the aforementioned structures, the foam compound experiences particularly little frictional resistance during filling and / or during reacting / expanding on the mounting board, in particular on the struts, so that the foam compound fills or occupies the gap between the mounting board and the cell contacting system in a particularly efficient manner. In order to promote and / or reinforce the adhesion connection between the mounting board and the cell contacting system, the surface elevation can have barbs or the like, for example.According to a further embodiment, the flow-promoting means is formed on the corresponding side of the struts by a flow-promoting surface. Here, a distinction is to be made between the formation of the aforementioned surface elevation or elevations and the surface treatment insofar as the respective surface elevation is produced by means of a shape-changing production and / or forming process (for example milling, rolling, embossing, etc.), whereas the flow-promoting surface is / is produced by using a mechanical, chemical, thermal and / or electroinductive process which does not result in any shape change of the surface-treated region. The foam mass can flow along the flow-promoting surface in a particularly efficient and low-resistance manner. For example, and this applies to the entire upper / lower side of the relevant strut or only to a specific partial region of the upper / lower side, a particularly smooth surface or a lotus blossom effect can be produced in order to promote the flow of the foam compound even more strongly. In order to promote and / or reinforce the adhesion connection between the mounting board and the cell contacting system, the surface can be designed to be particularly rough. It is to be understood that the surface elevation presented further above, in particular its structure, can have the flow-promoting surface.A possible development provides that the flow-promoting means is formed by means of one or more of the following surface treatments. In other words, one or more of the following surface treatments is / are used for producing the flow-promoting agent, in particular the surface elevation and / or the flow-promoting surface:loops,polishing,melting,coating (such as painting, powder coating, gluing, etc.),etching,- Pickling.This creates a particularly high-quality and particularly fluidically favorable surface.Since the mounting board generally (overlapping the embodiment) functions as an electrical insulator between the cell shoulders of the battery cells and the cell contact-making system, it is designed to be electrically non-conductive or electrically insulating. Nevertheless, for reasons of stability, for example, it can have a core made of an electrically conductive material, for example a metallic core. For such a case, a further possible embodiment provides that at least one outer jacket layer of the mounting board is formed from an electrically non-conductive plastic. In this case, it is in particular conceivable for the surface elevation(s) to be part of the core, that is to say to be formed from the electrically conductive material. In order to achieve the insulator effect, the core together with the surface elevations can be sheathed, in particular completely, with the outer sheath layer. It is of course equally conceivable for the mounting board to be formed completely from the electrically non-conductive plastic.Further features of the invention can be derived from the claims, the figure and the description of the figures. The features and combinations of features mentioned above in the description and the features and combinations of features shown below in the description of the figures and / or in the figure alone can be used not only in the respectively specified combination but also in other combinations or alone without departing from the scope of the invention.The drawing shows, in the only figure denoted by FIG. 1, a mounting board 1 for a traction battery of a motor vehicle. In FIG. 1, identical and functionally identical elements are provided with the same reference numerals. The mounting board 1 forms a component of the traction battery in its intended installation position, wherein the traction battery is integrated in its intended installation position into the purely electric or hybrid electric drivable motor vehicle. The traction battery and motor vehicle are not shown.When producing the traction battery, a liquid or pasty foam mass is filled into a housing of the traction battery, after which the foam mass fully reacts to form a dimensionally stable foam body. As a result, a cell package of the traction battery comprising battery cells (here round cells), the mounting board 1 and an electrically conductive cell contacting system of the traction battery are embedded in the foam body. In this case, the mounting board 1, which is here formed completely from an electrically insulating plastic in the example, faces the cell contact-making system in a surface-parallel manner, wherein a gap is formed between the cell contact-making system and the mounting board 1. In order to electrically isolate a cell shoulder side of the cell stack and the cell contacting system from one another, the mounting board 1 is arranged between the cell shoulder side and the cell contacting system. As can be seen from FIG. 1, the mounting board 1 has a grid structure, the elongate struts 2 of which delimit material-free contact-making zones 3. The battery cells or here the round cells have their positive pole and their negative pole each on a common end face, wherein an annular cell shoulder of the respective battery cell forms the negative pole and a central central region of the battery cell which is electrically insulated from the cell shoulder forms the positive pole. If the mounting board 1 is placed as intended on the cell shoulder side of the cell stack, the respective positive pole is arranged completely and the respective negative pole is arranged at least partially in one of the contact zones 3. The cell contact-making system extends through the contact-making zones 3 and is electrically conductively connected to the poles of the battery cells.On an underside 4 of the struts 2 and / or on an upper side 5 of the struts 2, a flow promoting means 6 is arranged, which is specifically configured to promote a flow of the pasty foam mass along the corresponding side 4, 5 of the struts 2. It can be seen in FIG. 1 that the mounting board 1 according to the present example has two or more flow-promoting means 6, which is specifically configured to promote a flow of a pasty foam mass along the corresponding side 4, 5 of the struts 2.The respective flow-promoting means 6 here has a surface elevation 7 in the example on the corresponding side 4, 5 of the struts 2-in the present case two or more surface elevations 7. It can be seen that a longitudinal extension direction of some of the surface elevations 7 is directed at a strut central region 8 of the corresponding strut 2. The respective surface elevation 7 can have a corrugations structure, a tears structure and / or a drops structure, etc., or can be formed from such a structure.Alternatively or additionally, the respective flow-promoting means 6 can be formed on the corresponding side 4, 5 of the struts 2 by a flow-promoting surface. This flow-promoting surface can be produced, for example, by grinding, polishing, fusing, coating, etching and / or pickling. In this example, the surface elevations 7 are accordingly surface-treated, so that they have the flow-promoting surface.The mounting board 1, the traction battery and the motor vehicle show a respective solution to how reliability of traction batteries can be increased. The invention is based on the basic idea of carrying out a structure optimization, in particular microstructure optimization, on surfaces of the mounting board 1 in order to promote a foam mass flow for reducing notch stresses in tear-risk regions of the cell contact system. The optimization(s) of the shape and structure of the mounting board 1 described herein always ensures a sufficiently large gap even under tolerance positions of the components during production in order to ensure a hundred percent foam wetting.List of reference characters1 Mounting board 2 Strut 3 Contacting zone 4 Underside 5 Upper side 6 Flow-promoting means 7 Surface elevation 8 Strut central regionReferences included in the specificationThis list of documents cited by the applicant has been produced in an automated manner and is only included for the better information of the reader. The list is not part of the German patent application or utility model application. The DPMA does not take any adhesion for any faults or omissions.Patent Literature citedDE 10 2013 020 369 A1

[0002]

Claims

Mounting board (1) for a traction battery for a motor vehicle, wherein the mounting board (1) - is configured to electrically isolate a cell shoulder side of a cell stack of the traction battery and an electrically conductive cell contacting system of the traction battery from one another, - has a grid structure, the elongate struts (2) of which delimit material-free contacting zones (3), wherein a flow promoting means (6) is arranged on an underside (4) of the struts (2) and / or on an upper side (5) of the struts (2), said flow promoting means being configured in a targeted manner to promote a flow of a pasty foam mass along the corresponding side (4, 5) of the struts (2).Mounting board (1) according to claim 1, characterised in that the flow-promoting means (6) has a surface elevation (7) on the corresponding side (4, 5) of the struts (2).Mounting board (1) according to Claim 2, characterized in that a direction of longitudinal extent of the surface elevation (7) of the respective strut (2) is directed at a strut central region (8).Mounting board (1) according to claim 2 or 3, characterized in that the surface elevation (7) has one or more of the following structures: - a corrugations structure, - a tears structure, - a drops structure,Mounting board (1) according to one of the preceding claims, characterized in that the flow-promoting means (6) is formed on the corresponding side (4, 5) of the struts (2) by a flow-promoting surface.Mounting board (1) according to one of the preceding claims, characterized in that the flow-promoting means (6) is formed by means of one or more of the following surface treatments: - grinding, - polishing, - melting, - coating, - etching, - pickling.Mounting board (1) according to one of the preceding claims, characterized in that at least one outer jacket layer of the mounting board (1) is formed from an electrically non-conductive plastic.Traction battery for a motor vehicle, in which a mounting board (1) designed according to one of the preceding claims, a cell pack and a cell contact-making system of the traction battery are embedded in a foam body.Motor vehicle having a traction battery designed according to Claim 8.

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