Battery module with improved adjacent cell protection and motor vehicle

Abstract

The invention relates to a battery module (14) for a motor vehicle, comprising a cell stack (12) having a plurality of cells (10) arranged next to one another in a stacking direction (y), each having a cell side (10a) as part of a stacking side (12a) of the cell stack (12) and an openable cell outlet (16) arranged on the respective cell side (10a), the cell vent (16) is arranged in an associated stack side sub-region (18) of the first stack side (12a). In this case, the battery module (14) comprises a frame insert (20) formed in one piece, which frame insert comprises a plurality of web-like frame sections (20a), which frame insert is arranged in the stack side subregion (18) of the stack side (12a) such that each openable cell vent (16) is framed by a part of the frame insert (20).

Description

TECHNICAL FIELD

[0001] The invention relates to a battery module for a motor vehicle, comprising a cell stack having a plurality of cells arranged side by side in a stacking direction, the plurality of cells each having a cell side as part of a stacking side of the cell stack and an openable cell vent arranged on the respective cell side, wherein the cell vent is arranged in a relevant stacking side-subregion of the first stacking side. Furthermore, the invention also relates to a motor vehicle having such a battery module. BACKGROUND

[0002] The cells of a battery module can have openable cell vents. In the event of a thermal runaway of a cell, it is thereby possible to prevent the cell from bursting uncontrollably and the cell can be vented in a defined manner through the subsequently opened cell vent. Such cell vents can be provided, for example, in the form of a burst disk or the like and are also generally referred to as cell vents. In a battery module having a plurality of cells, these cells are generally arranged in close proximity to one another. The openable battery vents are generally arranged on the same side of the cell stack here in order to be able to vent simply. If gas escapes from a cell that has undergone thermal runaway, it has hitherto not been possible or has been difficult to prevent at least a portion of this escaping gas stream from reaching an adjacent cell, in particular into the region of its openable cell vent. This can lead to a fire of the relevant adjacent cell.

[0003] It is therefore desirable to be able to better protect such adjacent cells of a cell that has undergone thermal runaway from the effects of this escaping gas stream.

[0004] DE 10 2021 208 346 A1 describes a battery for a motor vehicle, having a battery housing and cells arranged in the battery housing. The battery housing comprises a base on which the cell housings of the cells are arranged, wherein the base has a plurality of openings. The openings are opposite the respective emergency venting devices in the respective cell housing. Here, the cell housings each have a protrusion on their bottom face, which engages into the opening of the base arranged below the respective cell housing. Here, the protrusions can also be surrounded by a respective sealing element for sealing between the protrusion and the base.

[0005] However, this requires a very special design of the respective cell housing and thus also a very complex assembly of the battery module.

[0006] US 2013 / 0059175 A1 describes a battery with an exhaust system. Here, the battery comprises a bottom plate with openings which are respectively opposite to openable cell exhaust openings of cells comprised by the battery. Here, the openings in the bottom plate define exhaust channels. Here, between the respective cell and the bottom plate a respective O-ring is arranged for sealing. Here, the bottom plate is located between a housing plate and the cells. In the housing plate a valve can be arranged. The bottom plate can be provided with a recessed area or such an area which surrounds the housing plate. Gas can collect in this area, then the gas can be released through the valve in the housing plate.

[0007] However, this design requires an additional plate between the cells and the housing, which requires additional installation space and significantly increases the weight of the overall arrangement. However, the sealing by means of conventional O-rings is generally not very heat-resistant and cannot reliably maintain its sealing function when exhausting. SUMMARY

[0008] It is an object of the present application to provide a battery module and a motor vehicle which can protect adjacent cells as effectively as possible from the escaping gas stream when the cells are exhausted and which achieve this in as simple, space-saving and weight-reducing a manner as possible.

[0009] This object is achieved by a battery module and a motor vehicle having the features according to the respective independent claims. Preferred design options of the present application are the subject matter of the dependent claims, the description and the figures.

[0010] The battery module for a motor vehicle according to the present application comprises a cell stack with a plurality of cells arranged side by side in a stacking direction, the plurality of cells each having a cell side as part of a stacking side of the cell stack and an openable cell exhaust opening arranged on the respective cell side, wherein the cell exhaust openings are arranged in a relevant stacking side-subregion of the first stacking side. Here, the battery module comprises a frame insert formed integrally, the frame insert comprising a plurality of tab-like frame sections, the frame insert being arranged in the stacking side-subregion of the stacking side such that each openable cell exhaust opening is framed / enclosed by a part of the frame insert.

[0011] Due to the formation of the frame insert in this way, each openable cell vent is framed by a part of the frame insert, so that an improved protection function for the adjacent cells during cell venting is provided, since a barrier function is provided by the framing of the respective openable cell vent by the frame insert. In other words, by means of the frame insert, a flow of gas escaping from the openable cell vent to the openable cell vent of an adjacent cell is prevented or at least made difficult. Due to the fact that the frame insert comprises or consists of a plurality of tab-like sections and is furthermore not designed as a large-area solid plate, a significant saving in space and weight is additionally possible. Furthermore, due to the fact that the frame insert is designed as a one-piece component, the manufacture of the battery module and its individual components is also significantly simplified. For example, it is not necessary for each cell housing to be designed with a special geometry or with a flange or the like. Thus, the cells can be produced particularly simply and inexpensively. At the same time, it is also not necessary to provide each cell with a single, separate frame element and to arrange it in the respective position. The frame insert can simply be inserted as a whole between the cell stack and the other components of the battery module, for example the ventilation channel walls or the housing walls, or be placed, for example glued, on the cell stack. This likewise greatly simplifies the installation of the battery module. Thus, a particularly good protection function for the adjacent cells can be provided in a particularly space-saving, weight-reducing and structurally simple manner.

[0012] The frame insert can be formed, for example, of steel or stainless steel or of another material, in particular optionally also of a non-metallic fireproof material. Such fireproof materials are known from the prior art. Thereby, the frame insert can be designed simply as temperature-resistant or heat-resistant and maintain its protection function even in the event of venting of the cells.

[0013] The tab-like frame sections can be understood, for example, as sections of the frame insert which have an elongate and in particular narrow shape. For example, the width and height of the relevant frame section can be defined locally perpendicular to the longitudinal extension of such a frame section, said width and height being respectively smaller than the length of the frame section in the longitudinal extension. The width and height can be only a few millimetres, or even smaller, for example. The frame insert can be provided, for example, as a kind of grid structure. The regions, in particular free regions, which in the following are also referred to as sub-regions, which directly adjoin the respective openable cell vent in a defined first direction can be framed completely by the frame insert and spatially separated from one another perpendicular to the defined first direction. Thereby, a lateral flow perpendicular to the first direction is shielded in particular by the frame insert or is inhibited between the sub-regions.

[0014] The cells can be designed, for example, as prismatic cells. In particular, the cells can be lithium-ion cells, for example. The battery module can be used, for example, in a high-voltage battery of a motor vehicle. Here, such a high-voltage battery can also comprise a plurality of such battery modules.

[0015] The openable cell vent can be understood as an opening which is closed and which can be opened, that is to say, opened, in certain situations. Such an openable cell vent can thus have a closed state and an open state and can be transitioned from the closed state into the open state. This transition does not necessarily have to be reversible. It is possible, for example in an openable cell vent designed as a burst membrane, that a transition from the open state into the closed state is no longer possible.

[0016] The respective openable cell vent can be designed as a passive pressure-dependent openable cell vent, for example as a safety valve and / or a burst membrane and / or a predetermined breaking point in the cell housing, etc. Here, the openable cell vent is generally closed and thus fluidically seals the interior of the respective cell from the environment. From a defined overpressure, the respective cell vent opens and in turn establishes a fluid connection between the interior of the respective cell and its environment in order to enable the escape of gases from the cell.

[0017] According to a further advantageous design of the application, the battery module comprises a planar fire shield which is arranged on the side of the frame insert facing away from the cell stack, in particular wherein the fire shield is designed as a fire membrane and / or a fire paper and / or a fire plate. Here, the fire shield can in particular be designed in such a way that it can be burned through or said differently penetrated by the gas stream escaping from a thermally runaway cell. In the area of a cell vent which is still intact and thus not yet open, such a fire shield provides additional protection. By means of such a fire shield the cells can additionally be sealed from one another. Furthermore, the fire shield also provides additional protection against the ingress of dirt or dust or moisture, etc.

[0018] It is also advantageous here that the fire shield completely covers the frame insert. This in turn enables a simplified production, since it is not necessary to provide a respective shield for each individual sub-area of the frame insert. The fire shield can also be very easily fixed on the frame insert, for example glued or welded or otherwise fixed on the end side of the frame insert facing away from the cell stack.

[0019] According to a further advantageous design of the application, the frame insert is glued on the stack side, in particular in such a way that the frame insert does not come into direct contact with the stack side. Gluing the frame insert on the stack side provides a particularly simple and feasible solution for fixing the frame insert on the stack side or said differently for joining it to the stack side. Of course, other joining techniques can also be considered.

[0020] The frame insert can be glued, for example using adhesive tape, adhesive, etc. It is very advantageous here, for example, to use a heat-resistant structural adhesive. This ensures that the frame insert is reliably fixed on the cell stack and sealed with respect to the cell stack even in the event of a cell venting.

[0021] Generally, the frame insert can be connected to the stack side by means of a joining layer, for example made of the above-mentioned adhesive. The joining layer can be configured such that there is no direct contact between the frame insert and the stack side. This has the advantage, for example, if the frame insert is made of steel, that contact corrosion can be avoided, since the cell housing is generally made of aluminum, for example. However, if the frame insert is made of other materials, in particular refractory materials, for which there is no danger of contact corrosion even in direct contact with the stack side, it is not necessarily necessary to prevent direct contact between the frame insert and the stack side by means of a joining layer. The joining layer can also be configured such that contact between the frame insert and the stack side can be present locally.

[0022] According to a further advantageous design of the application, the frame insert has an outer frame which is arranged along the contour of the stack side-subregion and encloses the stack side-subregion, and one or more intermediate webs which divide the area enclosed by the outer frame into a plurality of subregions, wherein each subregion is opposite one openable cell vent and forms a venting channel. Thus, the respective subregions are advantageously shielded from one another by the intermediate webs. The outer frame can be designed, for example, rectangular, and the intermediate webs can be, for example, straight and parallel to one another and spaced apart from one another in the stacking direction. This enables particularly simple production of the frame insert.

[0023] It can also be provided here that the respective intermediate web separates two subregions arranged next to one another in the stacking direction from one another in the stacking direction. Thus, the respective such intermediate web is arranged adjoiningly to two subregions which are adjacent to one another in the stacking direction. This enables particularly material-saving design of the frame insert, since the respective subregions are, as it were, separated from one another by only one intermediate web of the frame insert. Thus, the respective intermediate web adjoins two subregions at the same time.

[0024] According to a further advantageous design of the application, the frame insert has an outer frame which is arranged along the contour of the stack side-subregion and encloses the stack side-subregion, wherein the frame insert comprises a plurality of subframes, wherein each subframe is associated with one openable cell vent and encloses this in a closed manner, wherein the subframes are connected to one another by means of the outer frame. Here, the respective subframes can be arranged spaced apart from one another in the stacking direction. Thus, there can be an intermediate region between each two subframes, which is a free region and is not any one of the subregions which is opposite one of the openable cell vents. This enables the respective subregions to be shielded from one another more effectively and more safely. The outer frame connects the subframes to one another, so that an integral component in the form of the frame insert can also be provided in a simple manner. Here, a section of the outer frame can also simultaneously form a section of one or more subframes.

[0025] In this case, the outer frame can also be designed, for example, in the shape of a rectangle or a generally rectangular shape with rounded corners, or in any other geometric shape. The sub-frames can also have, in principle, any geometric shape. According to a further advantageous design variant of the application, for example, it can be provided that the sub-frames have a geometric shape which corresponds to the geometric shape of the outer contour of the respective openable cell vent. If the openable cell vent is designed in the shape of a circle or an ellipse or an elongate shape with rounded corners, the sub-frames can accordingly also be designed in the shape of a circle or an ellipse or an elongate shape with rounded corners.

[0026] It is furthermore advantageous if the sub-frames are designed to be slightly larger than the openable cell vents. In other words, while the geometric shape of the sub-frames can correspond to the geometric shape of the openable cell vents, their dimensions do not necessarily have to correspond to the dimensions of the openable cell vents.

[0027] Here, the expression "each sub-frame is associated with an openable cell vent and encloses the openable cell vent in a closed manner" can be understood to mean that each sub-frame encloses a respective sub-area in a closed manner, which sub-area is opposite or adjoins the respective openable cell vent. These sub-areas can be spaced apart in the stacking direction by the aforementioned intermediate areas.

[0028] According to a further advantageous design variant of the application, in particular the sub-areas framed by the sub-frames taper as the distance to the openable cell vent associated therewith increases. This can be achieved in a simple manner by a corresponding geometric design of the web-like frame sections of the frame insert. For example, the aforementioned sub-frames can be designed in the shape of a funnel. This enables a more precise flow guidance of the outflowing gas.

[0029] The end side of the frame insert or, respectively, the end side of the sub-frames facing away from the cell stack can be connected, for example, to a venting area or a venting channel or to a venting chamber or the like. This enables a particularly advantageous and precise gas venting. The gas escaping from the cell can thus be discharged into the environment via the venting area or the venting channel or the venting chamber.

[0030] The application furthermore relates to a battery having a battery module according to the application or one of its design variants. The battery can be designed, for example, as a high-voltage battery or a medium-voltage battery. The battery can in particular be a traction battery for a motor vehicle. The battery can also optionally comprise a plurality of such battery modules.

[0031] The application furthermore relates to a motor vehicle having a battery module according to the application or one of its design variants. The motor vehicle can be designed, for example, as an electric vehicle.

[0032] The motor vehicle according to the application is preferably designed as a motor vehicle, in particular as a passenger motor vehicle or a utility motor vehicle, or as a bus or a motorcycle.

[0033] The application also comprises combinations of features of the described embodiments. Thus, the application also comprises the following implementation forms, each of which has a combination of features of the described embodiments, as long as these embodiments are not described as mutually exclusive. BRIEF DESCRIPTION OF DRAWINGS

[0034] Embodiments of the application are described below. Shown here is:

[0035] Figure 1 A cell of a cell stack of a battery module according to one embodiment of the application is schematically shown;

[0036] Figure 2 A bottom view of a battery module according to one embodiment of the application is schematically shown;

[0037] Figure 3 A side view of a battery module according to one embodiment of the application is schematically shown; and

[0038] Figure 4 A bottom view of a part of a battery module according to another embodiment of the application is schematically shown. DETAILED DESCRIPTION

[0039] The embodiments explained below are preferred embodiments of the application. In the embodiments, the described components of the embodiments are respectively individual, mutually independent features of the application, which also respectively improve the application independently of one another. The disclosure should therefore also include feature combinations different from the shown embodiment features. Furthermore, the described embodiments can also be supplemented by other features of the application already described.

[0040] In the drawings, identical reference signs respectively denote functionally identical elements.

[0041] Figure 1 A battery module 14 according to one embodiment of the application is schematically shown in Figure 2The electric cell 10 or the electric cell stack 12 is shown here in a side view, so in this case only a single electric cell 10 of the electric cell stack 12 can be seen. The electric cell stack 12, however, comprises a plurality of such electric cells 10 arranged side by side in the stacking direction y. The respective such electric cell 10 comprises an electric cell side 10a as part of a stacking side 12a of the electric cell stack 12, wherein on this electric cell side 10a an openable electric cell vent 16 is arranged. This electric cell vent can be designed for example in the form of a rupture disc or the like. This openable electric cell vent 16 can also be referred to as an electric cell vent. If a thermal runaway of the electric cell 10 occurs, an electric cell venting can take place through this electric cell vent 16.

[0042] In conventional battery modules, there is currently no reliable solution to ensure the protection of adjacent electric cells. So far, an air flow is formed which flows to adjacent vents, which can trigger a fire of the adjacent electric cells. Although various foam materials or combustion materials are currently being tested, they also do not provide a reliable solution.

[0043] Figure 2 A bottom view of the battery module 14 according to one embodiment of the application is schematically shown, i.e. opposite to the z-direction shown here. The z-direction can for example correspond to a vehicle vertical direction with reference to a prescribed installation position of the battery module 14 in a motor vehicle. As already mentioned, the battery module 14 comprises an electric cell stack 12 having a plurality of electric cells 10 arranged side by side in the stacking direction y. These electric cells are shown here in a bottom view of their respective electric cell side 10a, on which the respective openable electric cell vent 16 is provided. Here, the openable electric cell vent 16 is arranged in the relevant stacking side-subregion 18 of the stacking side 12a of the electric cell stack 12. The openable electric cell vent 16 can for example be arranged in a straight line in the stacking direction y. Here, in this stacking side-subregion 18, an integrally formed frame insert 20 is advantageously arranged as part of the battery module 14 on the electric cell stack 12, in particular on the stacking side 12a. The frame insert 20 here consists of a plurality of tab-like frame sections 20a, only a few of which are exemplarily provided with reference numerals. The frame insert 20 and its frame sections 20a are designed in such a way that each openable electric cell vent 16 is framed by a part of the frame insert 20.

[0044] In the present case, the frame insert 20 comprises an outer frame 22 which can be arranged along the contour or, respectively, the boundary contour of the stack side-subregion 18 and frames this stack side-subregion. It can be said that the outer frame 22 frames the entirety of the openable cell vent 16. Additionally, the frame insert 20 comprises a subframe 24. Here, each subframe 24 is precisely associated with an openable cell vent 16 and frames this associated cell vent 16. Certain sections of the outer frame 22 can at the same time also form a part of such a subframe 24. It can be said that each subframe 24 frames a subregion 26 which is directly connected to the openable cell vent 16 in the z direction. These subregions 26 can be free regions. These subregions 26 are in turn spaced apart in the stack direction y. In the stack direction y, intermediate regions 28 can accordingly be formed between the subframes 24. These intermediate regions can also be free regions.

[0045] In the present case, the geometry of the subframes 24 corresponds to the geometry of the cell vents 16. However, other geometries are also conceivable. It can be said that a chimney-like defined gas channel is formed by the subframes 24. This makes it possible for the gas flows of the cells 10 to be isolated from one another by the frame insert 20. Optionally, an additional seal can be provided on the top, i.e. on the side of the frame insert 20 which faces away from the cell stack 12, for example in the form of a fire shield 30. This seal can be designed, for example, as a fireproof film and / or a fireproof paper and / or a fireproof plate, etc. In the present case, the fire shield 30 completely covers the frame insert 20 and the region surrounded thereby, in particular the subregions 26 and the intermediate regions 28.

[0046] Figure 3 A side view of a battery module 14 according to an embodiment of the application is shown schematically. This battery module can in particular be designed as described in Figure 2 In order to avoid contact corrosion in particular when a steel insert is used as frame insert 20, the frame insert 20 can be connected to the cell stack 12, in particular to the stack side 12a in the stack side-subregion 18, for example by means of a connecting layer 32, for example a heat-resistant structural adhesive or an alternative connecting means. On the side of the frame insert 20 which faces away from the cell stack 12, a fire shield 30 in the form of a fireproof film, for example, is provided in order to seal the cells 10 from one another.

[0047] The frame insert 20 thus does not extend in the x direction over the entire stack side 12a, but only over a subregion of this stack side.

[0048] Figure 4A bottom view of a portion of a battery module 14 according to another embodiment of the application is shown schematically, viewed against the z-direction. The battery module 14 can in particular be designed as described above, with the exception of the differences described below, which essentially only relate to the geometry of the frame insert 20. In the present case, the frame insert 20 also comprises an outer frame 22 and a plurality of intermediate webs 24', which can also be referred to as partition webs 24'. Here, the frame insert 20 is also designed such that each cell vent 16 is completely framed by a portion of the frame insert 20. Here, the partition webs 24' separate each two sub-areas 26 in the stacking direction y, which can in turn be free areas, which are connected to the openable cell vent 16 in the z-direction. In the present case, the partition webs 24' extend linearly and parallel to one another in the y-direction. Other geometries are also possible. This can advantageously also shield each sub-area 26 from one another in the event of venting.

[0049] The web width B of each frame section 20a can be in the range of a few millimeters, for example in the range of 3 mm. In the x-direction, the maximum dimension C of the frame insert 20 can be in the range of a few centimeters, in the present case 79 mm. In the present case, the length L of the frame insert 20 in the y-direction is 102 mm. This can however also be selected differently depending on the number of cell vents 16 to be enclosed.

[0050] In general, the web thickness B and the web height in the z-direction are flexible, as is the shape of the frame insert 20. The sub-frames provided by the frame insert 20 can for example be rectangular or circular. Furthermore, they can also be conically converging inwardly and provide a kind of funnel.

[0051] Overall, the examples show how the cell vent protection for adjacent cells can be provided by the application. Thus, the mutual isolation of the airflow of the cells can advantageously be provided by the frame insert, which creates a chimney-like defined gas channel.

Claims

1. A battery module (14) for a motor vehicle, the battery module comprising a cell stack (12) having a plurality of cells (10) arranged side-by-side in a stacking direction (y), each of the plurality of cells having a cell side (10a) as part of a stacking side (12a) of the cell stack (12) and an openable cell vent (16) disposed on the respective cell side (10a), wherein, The cell exhaust port (16) is arranged in the relevant stack-side sub-region (18) of the first stack side (12a). Its features are, The battery module (14) includes an integrally formed frame insert (20) which includes multiple tab-shaped frame segments (20a) arranged in a stack-side sub-region (18) of the stack side (12a) such that each openable cell vent (16) is framed by a portion of the frame insert (20).

2. The battery module (14) according to claim 1, characterized in that, The battery module (14) includes a planar fireproof cover (30) arranged on the side of the frame insert (20) away from the cell stack (12), and in particular, the fireproof cover (30) is designed as a fireproof film and / or fireproof paper and / or fireproof board.

3. The battery module (14) according to any one of the preceding claims, characterized in that, The fireproof cover (30) completely covers the frame insert (20).

4. The battery module (14) according to any one of the preceding claims, characterized in that, The frame insert (20) is glued to the stack side (12a), specifically so that the frame insert (20) does not directly contact the stack side (12a).

5. The battery module (14) according to any one of the preceding claims, characterized in that, The frame insert (20) has an outer frame (22) and one or more intermediate pieces (24'), the outer frame being arranged along the contour of the stack side-sub-region (18) and framing the stack side-sub-region, the one or more intermediate pieces dividing the area surrounded by the outer frame (22) into multiple sub-regions (26), wherein each sub-region is opposite to an openable cell vent (16) and forms a venting channel.

6. The battery module (14) according to any one of the preceding claims, characterized in that, The corresponding intermediate interlayer (24') will have two sub-regions (26) arranged side by side in the stacking direction (y) separated from each other in the stacking direction (y).

7. The battery module (14) according to any one of the preceding claims, characterized in that, The frame plug-in (20) has an outer frame (22) arranged along the contour of the stack side-sub-region (18) and framing the stack side-sub-region. The frame plug-in (20) includes a plurality of sub-frames (24), each sub-frame (24) being associated with and enclosing an openable cell vent (16). The sub-frames (24) are interconnected via the outer frame (22).

8. The battery module (14) according to any one of the preceding claims, characterized in that, The subframe (24) has a geometry corresponding to the geometry of the outer contour of the corresponding openable cell vent (16).

9. The battery module (14) according to any one of the preceding claims, characterized in that, In particular, the sub-region (26) enclosed by the sub-frame (24) gradually becomes thinner as the distance to the corresponding associated, openable cell exhaust port (16) increases.

10. A motor vehicle having a battery module (14) according to any one of the preceding claims.

Images