Battery module and pressure balancing element of such a battery module

Abstract

To provide a battery module equipped with a relatively small pressure balancing element having a burst function capable of releasing all gas even in the case of gas discharge of hazard level 4.SOLUTION: A battery module (1) with a housing (2) which can accommodate a multiplicity of battery cells, wherein the housing comprises a pressure balancing element (3), wherein the pressure balancing element has a membrane (4), and wherein the pressure balancing element has a cross section (40) which is formed in an oval shape, as an elongated hole or in a keyhole shape.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention takes as its starting point a battery module according to the generic concept of the independent claims. A pressure balancing element is also the subject of the invention. [Background technology]

[0002] A battery module may include multiple individual battery cells, each having a positive voltage tap and a negative voltage tap, whereby the respective voltage taps are conductively connected to one another for conductive series and / or parallel connection among the multiple battery cells, thereby interconnecting them into a battery module. In particular, each battery cell may have a first voltage tap, particularly a positive voltage tap, and a second voltage tap, particularly a negative voltage tap, which are conductively connected to one another by cell connectors to form an electrical series and / or parallel connection, which in turn are interconnected to further batteries or to an entire battery system.

[0003] As is well known, such a battery module, for example a 48-volt battery module, includes a pressure balancing element, or PBU for short, which has, among other things, a circular membrane. Such a pressure balancing element is relatively small, with an opening diameter of, for example, 4 mm. In the event of a hazard level 3 gas release, in which less than 50% of the active material releases gas, the gas can escape through the membrane. In contrast, in the event of a hazard level 4 gas release, in which more than 50% of the active material releases gas, the battery module housing opens at various locations, which prevents the gas from escaping as intended.

[0004] Furthermore, such a battery module, for example a 48-volt battery module, may also include a pressure equalization element additionally having a burst function, as is well known. In particular, such a pressure equalization element may be integrated into the metal housing of the battery module. Such a pressure equalization element may be relatively large, for example, having an opening diameter of more than 18 mm. Furthermore, the membrane is made of plastic and is joined to the housing by ultrasonic welding. In this regard, the burst element is arranged behind the membrane in the direction of gas flow.

[0005] It is further known to arrange the bursting element directly on the membrane, in which case the bursting element is arranged in front of the membrane in the direction of gas flow, in which case the membrane is stripped off by the bursting element during the gas release process. Summary of the Invention

[0006] A battery module having the features of the independent claims offers the advantage that it is possible to provide a battery module with a relatively small pressure equalising element with a burst function that allows all gas to escape even in the event of a gas release of hazard level 4.

[0007] For this purpose, the present invention provides a battery module. The battery module includes a housing capable of accommodating a number of battery cells. In particular, the housing also accommodates the battery cells. Preferably, the battery cells are each formed as a lithium-ion battery cell. Furthermore, the housing of the battery module also includes a pressure equalizing element having a membrane.

[0008] Furthermore, the pressure equalization element has a cross section that is shaped as an oval, as a slot, or as a keyhole. The battery module is in particular a 48 volt battery module.

[0009] The measures recited in the dependent claims allow advantageous modifications and improvements of the device presented in the independent claims. In particular, one embodiment according to the present invention provides the advantage that the geometry of the pressure balancing element does not exceed the dimensions of the battery module housing, and therefore the pressure balancing element does not have a greater impact on the formation of the battery module housing, nor does it have a greater impact on the installation space or assembly line.

[0010] It is particularly useful if the pressure equalization element comprises a through-hole in which only a membrane is arranged. This offers the particular advantage that such an embodiment allows a relatively small pressure equalization element to be provided, which is protected only by the membrane. This makes it possible, inter alia, to avoid additional burst elements, in particular burst elements in the through-hole.

[0011] Such penetrations in the pressure equalizing elements are 100 mm 2 ~250mm 2 Advantageously, the area is between 200 mm 2 This allows reliable gas release to be achieved even in the event of a gas release of hazard level 4. In other words, the formation of an opening shaped as an oval, slot or keyhole allows for a relatively small area of ​​the opening.

[0012] It is advantageous if the membrane of the pressure equalization element is made of plastic, in particular polytetrafluoroethylene or polyethylene terephthalate, which has the advantage that a highly reliable membrane can be provided.

[0013] It is useful if the housing of the battery module is made of a metallic material, in particular aluminum, which has the advantage that a large number of battery cells can be reliably accommodated.

[0014] It is useful if the pressure equalizing element includes a frame element that is arranged in a materially connected manner, in particular welded, preferably laser welded, or glued, to the housing of the battery module, thereby providing a tightly formed joint, whereby corresponding sealing requirements, for example IP6K7, can be met between the pressure equalizing element and the housing of the battery module.

[0015] In this respect, it is preferred that the frame elements are asymmetrically configured, and in this respect the frame elements include, inter alia, surrounding projections or edges or support elements that protrude into the openings, so that a sufficient surface area can be provided for forming a material-bonding connection. It should be noted here that the frame elements can, of course, also be made symmetrically.

[0016] It should be noted here that an embodiment of the battery module or pressure balancing element according to the invention may result in an overall reduction in costs compared to solutions known from the state of the art.

[0017] The present invention also provides a pressure equalization element with a membrane for the battery module described above, which pressure equalization element has a cross section that is shaped as an oval, slot or keyhole.

[0018] Of course, this pressure balancing element can be further developed with all the variations described in connection with the battery module. Exemplary embodiments of the invention are illustrated in the drawings and are explained in more detail in the following description. [Brief explanation of the drawings]

[0019] [Figure 1] 1 is a partial external view of an embodiment of a battery module according to the present invention; [Figure 2] 1 is a cross-sectional view of a portion of an embodiment of a battery module according to the present invention. [Figure 3]FIG. 2 is a perspective view of a pressure balancing element of a battery module according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0020] FIG. 1 shows an external view of a portion of an embodiment of a battery module 1 according to the present invention. The battery module 1 has a housing 2 capable of accommodating a number of battery cells, which are not visible in Figures 1 to 3. In this regard, the housing 2 of the battery module 1 is made from a metallic material, in particular from aluminum.

[0021] Furthermore, the housing 2 of the battery module 1 comprises a pressure balancing element 3. Such pressure balancing element 3 further comprises a membrane 4. In this regard, this membrane 4 of the pressure balancing element 3 is made from plastic, preferably from polytetrafluoroethylene or polyethylene terephthalate.

[0022] In this regard, it can be seen from FIG. 1 that the pressure equalization element 3 has a cross section 40 formed as an elongated hole. The pressure equalization element 3 further comprises a through-hole 5 in which only the membrane 4 is arranged.

[0023] Such through-holes 5 in the pressure equalization element 3 are 100 mm 2 ~250mm 2 It has an area of ​​6 between. The pressure equalization element 3 further comprises a frame element 7. In this regard, the frame element 7 is arranged in a materially connected manner, for example in particular by welding, preferably by laser welding, or by adhesive bonding, on the housing 2 of the battery module 1.

[0024] FIG. 2 shows in cross section a portion of an embodiment of a battery module 1 according to the invention. In this respect, firstly the through-hole 5 can be seen, in which the membrane 4 is arranged. Furthermore, the frame element 7 can be seen, which is arranged in the housing 2 in a materially bonded manner.

[0025] FIG. 3 shows in perspective a pressure balancing element 3 of a battery module 1 according to the invention. In this respect it is possible to see the frame element 7 and the membrane 4. Furthermore it is possible to see that the pressure equalisation element 3 has a cross section 40 formed as an oblong hole.

[0026] In this respect, the frame element 7 is formed asymmetrically. In this respect, the frame element 7 comprises protrusions 71 or support elements 72. Such support elements 72 serve as breaking elements in the event of a possible burst. [Explanation of symbols]

[0027] 1 Battery Module 2. Housing 3 Pressure Equalization Elements 4 membrane 5 Through hole 6 area 7 Frame Elements 71 Protrusion 72 Supporting Elements 40 cross section

Claims

1. A battery module comprising a housing (2) capable of accommodating a number of battery cells, the housing (2) including a pressure equalization element (3), the pressure equalization element (3) having a membrane (4), A battery module, characterized in that the pressure equalization element (3) has a cross section (40) formed in an oval, slot or keyhole shape.

2. 2. The battery module according to claim 1, wherein the pressure equalization element (3) comprises a through-hole (5) in which only the membrane (4) is arranged.

3. The through-holes (5) of the pressure balancing element (3) are 100 mm ２ ~250mm ２ Between 200 mm and 300 mm, ２ 3. The battery module according to claim 1, wherein the battery module has an area (6) of less than 1000 .mu.m.

4. 4. A battery module according to claim 1, wherein the membrane (4) of the pressure equalization element (3) is made from plastic, in particular from polytetrafluoroethylene or polyethylene terephthalate.

5. 5. Battery module according to any one of claims 1 to 4, characterized in that the housing (2) of the battery module (1) is made from a metallic material, in particular from aluminium.

6. 6. The battery module according to claim 1, wherein the pressure equalizing element (3) comprises a frame element (7), the frame element (7) being arranged in a materially bonded manner, in particular by welding or adhesive, on the housing (2) of the battery module (1).

7. 7. A battery module according to claim 6, characterized in that the frame element (7) is formed asymmetrically.

8. 1. A pressure balancing element having a membrane (4) for a battery module (1), characterized in that the pressure balancing element (3) has a cross section (40) formed in an oval, slot or keyhole shape.

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