Battery assembly and method for detecting gas exhaust of cell

Abstract

The invention relates to a battery assembly (10) having a sensor device (18) for detecting a gas escape (26) of at least one cell (12) of the battery assembly (10), the cell (12) having an openable cell vent opening (16), the sensor device (18) for detecting a gas escape (26) comprising a sensor unit (20) having an electrical conductor (22) to which a test voltage can be applied, the sensor unit (20) comprising an electrical conductor (22) to which a test voltage can be applied. The sensor unit (20) is arranged in such a way that the gas (26) escaping from the cell vent opening (16) impinges on the sensor unit (20), and the electrical conductor (22) can be damaged by the gas (26) exiting from the cell vent opening (16). Here, the sensor unit (20) is designed in such a way that the electrical conductor (22) can be damaged by the outflow pressure of the gas (26) escaping from the cell vent opening (16) in the event of thermal runaway of the cell (12).

Description

Technical Field

[0001] The invention relates to a battery assembly having a sensor device for detecting gas escape from at least one battery cell of the battery assembly, wherein the battery assembly comprises at least one battery cell having an openable battery cell exhaust opening, wherein the sensor device for detecting gas escape comprises a sensor unit having an electrical conductor to which a test voltage can be applied, wherein the sensor unit is arranged such that gas escaping from the battery cell exhaust opening impinges on the sensor unit, wherein the electrical conductor can be damaged by gas flowing out of the battery cell exhaust opening. Furthermore, the invention relates to a method for detecting gas escape. Background Art

[0002] Internal pressure may build up in individual cells of a battery, such as a high-voltage battery system, for a variety of different reasons. This occurs, for example, in the event of a thermal runaway of such a cell. The cell usually has a weakening provided for this purpose in the housing, which is also usually referred to here as an openable cell venting opening, in order to prevent the cell from bursting. The openable cell venting opening thus enables controlled venting of the cell in the event of an overpressure. Cell venting indicates a possible serious fault in the battery and subsequent damage, up to system heat propagation. For this reason, it is advantageous to detect such a fault situation, for example in order to warn the user and initiate safety functions within the high-voltage battery.

[0003] DE 10 2012 212 378 A1 describes a venting device for conducting a fluid from at least one battery cell, wherein the venting device can be coupled to the battery cell by means of flow technology and has a signal generating device, by means of which the conduction of the fluid can be detected and a corresponding signal can be generated. In this case, the signal generating device can include a breaking element, which is designed as a valve and is arranged in a venting opening of the venting device. An electrical conductor element can be embedded in the breaking element. Thus, the venting device itself can form an openable battery cell venting opening of the battery cell.

[0004] The integration of the signaling device into the openable cell ventilation opening of the cell itself results in a relatively complex design of each individual cell.

[0005] DE 10 2014 006 807 A1 describes a battery system having at least one single cell arranged on a housing, wherein the single cell has a cell valve device that opens at a predeterminable cell internal pressure. In addition, the battery system includes a sensor device to detect the opening of the cell valve device and / or detect the temperature inside the housing. For this purpose, the sensor device can include a control wire that can extend on the cell valve device. The wire can be designed as a thermal resistor so that its resistance and the voltage drop caused by it change when the temperature changes. The wire can also be designed as an optical fiber, which changes its optical properties when the temperature changes. The control wire can also include a temperature measurement part.

[0006] If the temperature at the cell or the escaping gas is used to detect the gas escape, the corresponding element is positioned as directly as possible at the gas escape site. However, this may hinder the gas escape from the cell. In addition, some cell manufacturers do not allow the arrangement of external components in the area of ​​the openable cell exhaust opening or at the cell itself. In the case that the gas escaping from the cell is not hot enough, which occurs, for example, in the case of so-called cold exhaust, such gas escape cannot be detected using the above-mentioned measures or can only be detected in a very complicated manner. Summary of the invention

[0007] The object of the present invention is to provide a battery assembly and a method for detecting gas evolution which allow gas evolution of a battery cell to be detected in the most efficient manner possible and at the same time in the most diverse situations possible as reliably as possible.

[0008] This object is achieved by a battery assembly and a method having the features according to the respective independent claims. Advantageous embodiments of the invention are given by the dependent claims, the description and the drawings.

[0009] The battery assembly according to the invention comprises a sensor device for detecting gas escape from at least one battery cell of the battery assembly, the at least one battery cell in turn comprising an openable battery cell vent opening. Here, the sensor device for detecting gas escape comprises a sensor unit having an electrical conductor to which a test voltage can be applied, wherein the sensor unit is arranged such that gas escaping from the battery cell vent opening impinges on the sensor unit, wherein the electrical conductor can be damaged by gas escaping from the battery cell vent opening. Here, the sensor unit is designed in such a way that the electrical conductor can be damaged by the flow pressure of the gas escaping from the battery cell vent opening in the event of thermal runaway of the battery cell.

[0010] The present invention is based on the knowledge that in order to detect gas escape, not only the temperature of the escaping gas can be used, but also the outflow pressure. Thus, for example, the outflowing gas can also be detected independently of the temperature. In addition, the present invention is based on the knowledge that in order to detect gas escape using the outflow pressure, it is not necessary to design the sensor unit itself as an openable battery exhaust opening or to integrate it. Therefore, the electrical conductor for detecting gas escape can be advantageously constructed separately from the openable battery exhaust opening of at least one battery cell, so that conventional batteries can be used to detect gas escape. In other words, gas escape can be detected here not only in a battery cell of a specific configuration, but also in principle in any battery cell with an openable battery exhaust opening. Therefore, "providing a sensor unit separated from the battery cell for detecting gas escape" can achieve a particularly cost-effective and effective detection method. In addition, by using the outflow pressure of the gas flowing out of the battery cell exhaust opening, the electrical conductor of the sensor unit that can be damaged by the outflow pressure can be arranged at a significantly larger distance from the battery cell exhaust opening. In addition, for this purpose, the sensor unit does not have to be fixed on the battery cell. This effectively prevents the escape of gas from the cell from being impeded, and also allows the manufacturer's predefined parameters to be adhered to without problems.

[0011] At least one battery cell can be designed as a lithium-ion battery cell, for example. The openable battery cell vent opening of the battery cell can be designed as a preset rupture point in the battery cell housing of the battery cell. The battery cell vent opening can be designed as a rupture membrane or a high-pressure valve, etc. The openable battery cell vent opening is an element that opens passively, for example, in a pressure-dependent manner, and is therefore suitable for opening the opening without active control.

[0012] In this case, the battery assembly can include not only one such battery cell, but preferably also a plurality of such battery cells, as will be described in detail below. The sensor device can include only one or a few electrical conductors for detecting the gas evolution of one of the plurality of battery cells. In particular, if the battery assembly has a plurality of battery cells and not just a single battery cell, the number of electrical conductors required for this purpose can be significantly smaller relative to the number of battery cells of the battery assembly. As a result, the sensor device is designed to be particularly efficient.

[0013] The electric conductor may include an electric conductor or be designed as an electric conductor. In this case, the electric conductor may be made entirely of an electrically conductive material, preferably a metal. In this case, preferably, the electric conductor itself does not have a sheath like a cable. The electric conductor may be designed, for example, as a single electrically conductive wire, in particular a stranded wire. The electric conductor may also be a conductor track or a conductor track assembly, which is, for example, arranged on a conductor track substrate or embedded in a conductor track substrate, which may be a bracket described in detail later. Optionally, this sheath may be part of a sensor unit, as described in detail later, but not part of the electric conductor itself. In this case, the electric conductor should be made entirely of an electrically conductive material.

[0014] In order to arrange the sensor unit so that the gas escaping from the battery cell exhaust opening hits the sensor unit, the sensor unit may be opposed to at least a portion of the battery cell exhaust opening in a certain direction (hereinafter also referred to as a first direction). Here, the sensor unit is not necessarily arranged on the battery cell exhaust opening in a contacting manner, but may also be arranged to be spaced apart from the battery cell exhaust opening.

[0015] Since the test voltage can be applied to the electrical conductor, damage to the electrical conductor can be simply detected by the outflow pressure of the gas flowing out of the exhaust opening of the battery cell. For this purpose, a measuring device can be provided as part of the sensor device, which detects and evaluates at least one electrical parameter related to the electrical conductor in order to detect damage to the electrical conductor, in particular the cutting of the electrical conductor. The measuring device can also be designed to apply a test voltage to the electrical conductor. In addition, the measuring device is designed to measure the electrical parameter during the period when the test voltage is applied to the electrical conductor.

[0016] Therefore, another very advantageous design of the present invention is that the sensor unit is designed to detect the damage of the wire to which the test voltage is applied in relation to the measured electrical parameter corresponding to the wire and to detect the gas escape in relation to the detected damage of the wire. Such measured electrical parameters can be, for example, current intensity or resistance, such as the wire resistance of the electrical wire, or multiple of these electrical parameters can also be detected and evaluated. If the electrical wire is, for example, applied with voltage, a current is thereby caused to flow through the electrical wire. In this case, the interruption of the electrical wire leads to the interruption of the current accordingly. Just when the electrical wire is used or is to be used to detect the gas escape of any of the multiple cells of the battery assembly, the electrical wire can be designed more complexly. For example, the electrical wire can be designed as a wire assembly or a conductor line assembly in this case, which, for example, has multiple wire sections, which can be connected in parallel and / or in series with each other. Just in the case of a parallel circuit, the wire interruption in the section of such a parallel branch does not necessarily lead to a complete interruption of the current, because the current can also be guided through other branches. However, damage to such a parallel branch can be determined in a simple manner by a change in the total resistance of the line assembly or conductor track assembly. In this case, it is very advantageous, for example, to detect the above-mentioned electrical variable, at least the resistance of the electrical line, for example its total resistance, wherein, if the electrical line comprises a plurality of line branches or line sections, the total resistance relates to the entire line assembly formed by the plurality of sections or branches.

[0017] In another very advantageous embodiment of the present invention, the electrical conductor is arranged at a distance from the openable battery cell exhaust opening, and / or the sensor unit has a bracket made of a non-conductive material, in particular plastic, on which the electrical conductor is arranged and / or embedded in the bracket.

[0018] On the one hand, it is very advantageous if the electrical conductor is arranged at a distance from the openable cell ventilation opening. Thus, "the electrical conductor is arranged at a distance from the openable cell ventilation opening" can relate to the entire sensor unit, i.e., including the holder, for example, or only to the electrical conductor itself. Furthermore, the electrical conductor can here only have a distance from the cell ventilation opening or from the entire cell including the cell ventilation opening.

[0019] Here, the distance between the electric conductor and the exhaust opening of the battery cell can also be caused only by the thickness of the insulating material of the bracket. However, the distance can also be greater than the thickness of the insulating material (if present). The distance provides electrical insulation on the one hand. Additionally or alternatively, the electrical insulation can also be provided by an electrically insulating bracket. The significant advantage of setting the distance is that the components do not have to be directly arranged or installed on the openable battery exhaust opening of the battery cell. Therefore, the obstruction of gas escape can be significantly more effectively prevented, and the manufacturer's pre-given parameters can also be followed more simply. In addition, by setting the bracket, significantly greater flexibility is provided in terms of the arrangement possibilities, just like in terms of the construction possibilities of the sensor unit, especially in terms of the geometric construction possibilities for providing a certain mechanical structure, such as the damageability of the electric conductor. If the electric conductor is embedded in such a bracket, electrical insulation can also be provided to the outside at the same time by the bracket. This situation, for example, can also make the sensor unit at least partially arranged on multiple batteries or at least one battery. In addition, optionally, a certain structural rigidity can also be provided for the sensor unit by setting the bracket, which does not have to be provided by the rigidity of the electric conductor itself. This can also be achieved, for example, by designing the electrical conductor as a very thin wire, i.e. a stranded wire or a conductor line, without thereby making the sensor unit as a whole unstable. Thin wires or thin conductor lines can be damaged significantly more easily, thereby in turn significantly more reliably detecting gas escapes. The bracket can, for example, provide a frame and / or be designed as a support plate and / or a support film. In addition, as will be described in detail later, a certain flow resistance can also be provided by the bracket in relation to the gas flowing out of the exhaust opening of the battery cell using the outflow pressure, in particular, this does not have to be achieved by a special construction scheme of the electrical conductor itself. For example, a very large blocking surface related to the flow resistance can be provided by the bracket, while the electrical conductor or the electrical conductor itself is designed very thinly. In addition, the fixing of the electrical conductor is simplified by providing a bracket, which optionally does not have to be designed as thin as a gold or silver wire, as this is preferred for the electrical conductor.

[0020] In another advantageous embodiment of the present invention, a free space / exposed space, in particular a gap, is provided between the cell vent opening and the sensor unit in a first direction. The advantage of this gap is that a blockage of the gas escape is prevented and furthermore the component does not have to be arranged directly on the cell vent opening. Therefore, preferably, there is no contact between the sensor unit and the cell vent opening of at least one cell.

[0021] In another advantageous design of the present invention, the sensor unit has a preset breaking point, wherein the wire can be damaged by damage or breakage of the sensor unit at the preset breaking point, in particular, wherein the preset breaking point is constructed in the bracket. Therefore, the preset breaking point can also be constructed only in the bracket and not in the wire, or can also be constructed in the bracket and the wire. In particular, when there is no bracket at all, the preset breaking point can also be constructed only in the wire. Therefore, "providing a preset breaking point" makes it easier to damage the electrical wire in the event of gas escape. This makes it significantly more reliable and more sensitive to detect such gas escape. Here, the preset breaking point can in principle be arranged in the bracket and / or in the electrical wire. The significant advantage of "arranging in the bracket" is that there is no need to carry out complex processing of the electrical wire itself, and the electrical wire can be simply designed as a thin stranded wire or a thin wire, which can be easily damaged, in particular, can be cut due to its small diameter. In addition, the significant advantage of "preset breaking point is constructed on the support" is that the support can provide a correspondingly large blocking surface with respect to flow resistance at least in the area opposite to the exhaust opening of the battery cell, and at the same time can realize a simple interruption of the sensor unit through the preset breaking point in the support. Therefore, the local more solid or widened construction of the support does not lead to an overall increase in the triggering threshold of the sensor unit. Therefore, the preset breaking point can also be constructed only in the support and not in the wire, or can also be constructed in the support and the wire. In particular, when there is no support at all, the preset breaking point can also be constructed only in the wire.

[0022] In another advantageous design of the present invention, the sensor unit has a detection section, which is directly opposite to the cell exhaust opening of the battery cell in the direction of gas escape, wherein the bracket has a bracket surface at least in the detection section, which is wider than the conductor surface of the electrical conductor in the second direction. Therefore, the bracket can be widened in the detection section or at least wider than the electrical conductor. Its significant advantage is that a large flow resistance can be provided with respect to the gas flowing out of the battery cell by such a wide bracket surface. As a result, the pressure effect of the gas outflow pressure on the sensor unit is particularly large, and its triggering can be ensured particularly simply.

[0023] The sensor unit as a whole may also include, for example, only an electrical conductor and / or a support. For example, the sensor unit may be designed as an electrical conductor wrapped by the insulating material of the support or as a conductor assembly or conductor line assembly wrapped electrically insulated. Here, the detection section defines a certain area of ​​the wrapped conductor assembly or conductor line assembly. In particular, the detection section defines the following area of ​​the sensor unit, which is arranged directly opposite to the openable cell exhaust opening of at least one cell.

[0024] In another advantageous embodiment of the present invention, the battery assembly has a plurality of cells with corresponding openable cell exhaust openings. The plurality of cells can be configured as described for at least one cell. In addition, the sensor unit can include a plurality of detection sections, wherein each detection section corresponds to exactly one cell exhaust opening, wherein the sensor unit has a plurality of preset fracture locations, wherein each detection section is provided with at least one of the preset fracture locations, the at least one preset fracture location being in particular arranged in the edge region of the detection section and / or adjacent to the detection section. Preferably, only one preset fracture location is provided for each detection section. Thus, when the gas impinges on the detection section and a fracture occurs at the corresponding preset fracture location, a lever effect can be used to bend the detection section in the flow direction without the detection section being completely detached from the rest of the sensor unit by another fracture at another location.

[0025] Since the sensor unit includes a plurality of detection sections, which correspond to the respective cell exhaust openings of the cells, the sensor unit can be used to detect the gas escape of any of the plurality of cells. Therefore, no additional sensor unit needs to be provided. For example, such a sensor unit can be provided for each battery module.

[0026] The battery assembly may, for example, provide or be a battery, in particular a high-voltage battery. The battery, for example a high-voltage battery, may in turn have a plurality of battery modules. Here, the battery module may include a plurality of cells. The cells may, for example, be designed as lithium-ion cells. If a plurality of sensor units are provided, for example, one sensor unit is provided for each module, these sensor units may be connected to a common measuring device of the sensor device, i.e., electrically and / or communicatively connected.

[0027] In another advantageous design of the present invention, the sensor unit comprises a plurality of connecting sections, wherein the individual detection sections are connected to each other by the plurality of connecting sections, wherein the respective connecting sections are narrower than the respective detection sections in the second direction, in particular wherein a conductor structure is formed by the connecting section and the detection section, the conductor structure comprising two opposing longitudinal bars and a plurality of crossbeams connecting the two longitudinal bars, wherein each crossbeam comprises a detection section. The term "conductor structure" here relates to the geometric design of the sensor unit. The geometry can be similar to a conductor. Thus, two opposing longitudinal bars and a plurality of crossbeams connecting the two longitudinal bars, similar to a crossbeam of a conductor, can be formed by the individual sections of the sensor unit, namely the connecting section and the detection section. This geometry is particularly advantageous in the case where the cells are designed, for example, as prismatic cells or bag-shaped cells and are arranged in the form of a cell stack relative to each other. In this case, the exhaust openings of the individual cells can be along an imaginary line. The two longitudinal rods extend respectively along the stacking direction on both sides of the corresponding openable battery cell exhaust openings, while the corresponding crossbeams are arranged to extend perpendicularly to the stacking direction through the openable battery cell exhaust openings, but preferably do not contact the battery cell exhaust openings. It is accordingly advantageous that each crossbeam has a detection section in which the sensor unit is widened. The detection section can be consistent in its area with the area of ​​the openable battery cell exhaust opening corresponding to it. The width of the remaining sections of the sensor unit, i.e. the connecting sections, can be designed to be significantly smaller. In addition, a frame for the sensor unit is provided by the described conductor structure. The frame can position the sensor unit particularly stably. This makes it possible in particular to manufacture the sensor unit as a separate component and position it as a whole, for example, in the area between the battery module and a housing component of the battery housing, for example a housing bottom which can be designed as a cooling bottom, or to arrange it on the bottom side, i.e. on the side of the housing component opposite the battery module or the battery cell, and to fix it to such a housing component itself, wherein the housing component has a recess between the area of ​​the sensor unit (including the detection section) and the area of ​​the cell venting openings in which the cell venting openings of the module cells are arranged. In this case, fixing to the battery module itself is not mandatory. Fixing here can be understood in particular as fixing by material bonding, for example by means of bonding or welding, or other fixing, for example by means of screwing or riveting, etc. The sensor unit can, for example, be clamped between the battery module and the housing component and / or can be fixed only to the housing component, for example by means of bonding.

[0028] It is also conceivable that the longitudinal rod and the crossbeam are located in a common plane, or that the longitudinal rod and the crossbeam are not located in a common plane. In this case, it can be provided, for example, that the longitudinal rod is at a smaller distance from the battery cell than the crossbeam. In other words, the distance from the battery cell can be increased in the crossbeam region. In this case, the detection area or detection section of the sensor unit is correspondingly larger than the distance from the battery cell in the remaining area. As a result, a particularly large distance can be provided for the sensor unit just in the area of ​​the exhaust opening of the battery cell. In addition, it is also possible to arrange the sensor unit on the battery cell, i.e., through the longitudinal rod, for example, only by abutting against the battery cell or the battery cell composite structure, i.e., the battery cell stack, or also by bonding or the like.

[0029] The connecting section can be arranged in contact with the cell at least in certain areas in the region of the cell housing, wherein no cell ventilation opening is arranged.

[0030] In another advantageous design of the present invention, the bracket is designed as a support plate and / or a support film. The sensor unit can include a plurality of detection sections, wherein each detection section corresponds to exactly one battery exhaust opening and is arranged to be opposite to the battery exhaust opening, in particular in the first direction. Such a detection section further defines the following region of the bracket, in which a conductor section of an electric wire is provided. The sensor unit preferably includes a plurality of preset fracture locations, wherein at least one preset fracture location is provided for each detection section, wherein preferably, each such preset fracture location is designed as a preset fracture line, which partially or completely surrounds or surrounds the detection section. The preset fracture line can also be designed as a U-shaped line and surrounds the detection section except for a lateral structure of the detection section. Then when the gas flow hits, the detection section can be folded similar to a valve. When the preset fracture line completely surrounds the detection section, the detection section can be punched out when the gas flow hits. The conductor can be arranged on a support plate or a support film or embedded therein. Here, the conductor can have a wire assembly, which includes a crossbeam section and a longitudinal connector. The crossbeam sections extend substantially parallel to each other. Here, each detection section comprises at least one crossbeam section. The crossbeam sections can also form a conductor loop, which extends from one side along the third direction into the detection section and, conversely and in the opposite direction to the third direction, returns to the side. The longitudinal connector connects the individual crossbeam sections to each other. Here, the longitudinal connector extends substantially in the second direction. By means of the conductor assembly, for example, a conductor structure can also be provided, in particular for providing a parallel circuit of the detection sections, or a meandering or serpentine extension, in particular to provide a series circuit of the detection sections.

[0031] In another advantageous design of the present invention, the battery assembly includes a shell component, in particular a cooling plate, wherein at least one battery cell includes a first battery cell side having a first area, a second area and a third area, wherein an openable battery cell exhaust opening is arranged in the second area, and the second area is arranged between the first area and the third area along a third direction, wherein the first area and the third area are respectively arranged on the shell component via interface materials, wherein a free area is provided below the second area in the first direction, a sensor unit is arranged in the free area, and the free area is located between two sections of the shell component along the third direction.

[0032] This design is particularly advantageous in the case where the housing component is a cooling bottom of the battery housing or a cooling cover or other cooling device of the battery housing, which is also a housing component. As a result, the battery cell can be thermally connected to the housing component as well as possible via the interface material. The interface material can also be designed as a thermal interface material, such as a caulking agent, i.e. a caulking compound or a thermally conductive adhesive. If the housing component is not a cooling device, "the battery cell is constructed or connected to the housing component via an interface material" is also advantageous for other reasons, for example to increase the structural rigidity of the entire assembly. In addition, an adhesive can be used as an interface material here, and other fixing possibilities of the battery module on the housing can be omitted.

[0033] Here, the free area facilitates the escape of the gas flow from the exhausted cell and at the same time provides space for arranging a sensor unit there for detecting the gas flow. The free area can be designed essentially rectangular or square, wherein the distance between the free area and / or the sensor unit and the exhaust opening of the cell has only a very small height in the first direction, for example only a few millimeters and in particular less than 1 centimeter.

[0034] Furthermore, the invention relates to a motor vehicle having a battery assembly according to the invention or one of its embodiments.

[0035] The invention further relates to a method for detecting gas emission from at least one battery cell, the at least one battery cell having an openable battery cell vent opening, wherein a sensor unit having an electrical conductor to which a test voltage is applied is used for detecting the gas emission, wherein gas escaping from the battery cell vent opening impinges on the sensor unit and damages the conductor, wherein the gas emission is detected by detecting damage to the electrical conductor. In this case, the electrical conductor is damaged by the outflow pressure of the gas escaping from the battery cell vent opening in the event of a thermal runaway of the battery cell.

[0036] The advantages described for the battery assembly according to the invention and its embodiments apply in the same manner to the method according to the invention.

[0037] In response to the detection of a gas escape, a signal may be emitted and / or measures may be initiated.

[0038] The invention also includes improvements of the method according to the invention which have the features already described in conjunction with the improvements of the battery assembly according to the invention. For this reason, corresponding improvements of the method according to the invention will not be described here.

[0039] The motor vehicle according to the invention is preferably designed as a car, in particular as a passenger car or a commercial vehicle, or as a bus or a motorcycle.

[0040] The invention also includes combinations of features of the described embodiments. Therefore, the invention also includes implementations which each have a combination of features of a plurality of the described embodiments, as long as these embodiments are not described as mutually exclusive. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The embodiments of the present invention are described below. As shown in the figure:

[0042] Figure 1 A schematic diagram of a battery assembly in a non-triggered state of a sensor unit is shown in a cross-sectional view according to an embodiment of the present invention;

[0043] Figure 2 According to one embodiment of the present invention, Figure 1 A schematic diagram of a battery assembly in a triggered state of a sensor unit;

[0044] Figure 3 A schematic diagram of a battery assembly having a sensor unit according to another embodiment of the present invention is shown;

[0045] Figure 4 A schematic diagram of a battery assembly having a sensor unit according to another embodiment of the present invention is shown;

[0046] Figure 5 A schematic diagram showing a sensor unit for a battery assembly in a top view according to an embodiment of the present invention;

[0047] Figure 6 A schematic diagram of a sensor unit for a battery assembly is shown according to another embodiment of the present invention;

[0048] Figure 7 A schematic diagram showing a portion of a sensor unit for a battery assembly according to another embodiment of the present invention;

[0049] Figure 8 A schematic cross-sectional view showing a battery assembly according to another embodiment of the present invention; and

[0050] Fig. 9Another embodiment according to the present invention is shown from below Figure 8 Schematic diagram of the battery components in . DETAILED DESCRIPTION

[0051] The embodiments described below are preferred embodiments of the present invention. In the embodiments, the described components of the embodiments are respectively individual features of the present invention that can be regarded as independent of each other, and these features also improve the present invention independently of each other. Therefore, the present disclosure should also include feature combinations that are different from the illustrated embodiment feature combinations. In addition, the embodiments may also be supplemented by other features in the already described features of the present invention.

[0052] In the figures, the same reference numerals respectively denote elements with the same function.

[0053] Figure 1 A schematic cross-sectional view of a battery assembly 10 is shown according to one embodiment of the present invention. The battery assembly 10 includes at least one battery cell 12, but preferably includes a plurality of such battery cells, which can, for example, form a battery module 14 having a plurality of battery cells 12 arranged side by side in a stacking direction x. A high-voltage battery or a part thereof can be provided by the battery assembly 10, for example. In the present example, the battery cell 12 has an openable battery cell exhaust opening 16 on its lower side 12a, which can, for example, be arranged in the form of a battery cell membrane in the battery cell housing of the battery cell 12. With reference to the preferred installation position of the battery assembly 10 in a motor vehicle, the z direction shown here preferably corresponds to the vehicle height direction. When a certain internal pressure of the battery cell is exceeded, the openable battery cell exhaust opening 16 opens a path for gas escape. In order to detect this situation, the battery assembly 10 includes a sensor device 18, which in turn includes a sensor unit 20. In addition to the sensor unit 20, the sensor device 18 can also include, for example, a measuring device (not shown in detail), which is designed, for example, to apply a test voltage to an electrical line 22 in the form of an electrical conductor 22 included in the sensor unit 20 and to detect and evaluate at least one electrical variable corresponding to the conductor 22, such as resistance or current intensity.

[0054] Thus, the sensor unit 20 comprises, as already described, an electrical conductor 22 and a support 24, in particular made of an electrically insulating material, such as plastic. The electrical conductor 22 (hereinafter also referred to as conductor 22) can be arranged on the support 24 or can also be completely embedded therein, so that the electrical conductor 22 is completely electrically insulated from the outside by the support 24, for example, except for two connection points 22a, 22b (see Figure 5 and Figure 6 ), the sensor unit 20 can be connected to the measuring device via this connection point and the conductor 22 can be applied with a test voltage via this connection point.

[0055] In order to simplify the description, the sensor unit 20 can be divided into a plurality of sections. In this case, the sensor unit 20 preferably has a corresponding detection section 20a for each openable battery cell exhaust opening 16, which can also be referred to as a detection area 20a. In this detection section 20a, the support 24 can be configured in a widened manner relative to the electrical conductor 22, in particular in this example, along and opposite to the x-direction shown. The surface F provided by the support 24 in the detection section 20a (which is oriented perpendicular to the z-direction shown) can correspond to the dimensions of the openable battery cell exhaust opening 16 in terms of its geometric design. A particularly large flow resistance is provided in the detection area 20a by the support 24 with respect to the gas flow 26 escaping from the battery cell (see Figure 2 ), the gas flows in Figure 2 Schematically indicated by arrows 26. This has the significant advantage that the temperature of this escaping gas 26 cannot or cannot be used exclusively for decomposing the sensor unit 20, but the gas pressure occurring there and acting on the sensor unit 20 in particular in the detection area 20a can also be used in addition or alternatively.

[0056] If the battery assembly 10 includes a plurality of battery cells 12, the sensor unit 20 may also include a corresponding number of detection sections 20a, such as in Figure 5 and Figure 6 As can be seen in FIG. The remaining section of the sensor unit 20 is referred to as the connecting section 20 b, which can also be referred to as the connecting region 20 b. In this case, not all connecting sections 20 b have to include electrical conductors 22, but can also be formed, for example, only by the electrically insulating material of the support 24. This is particularly relevant for the line routing of the electrical conductors 22 and the circuit formed thereby and its design, as will be described in detail later.

[0057] It is also advantageous if the support 24 or, in general, the sensor unit 20 is designed to be narrower in the x direction in the region of the connecting section 20b than in the detection section 20a. This facilitates damage to the sensor unit 20 in the event of a gas escape 26. It is also advantageous if the sensor unit 20 has at least one predetermined breaking point 28, which in this example is arranged in one of the connecting sections 20b and adjoins the detection section 20a or is adjacent in a predetermined manner.

[0058] Furthermore, the sensor unit can be designed geometrically as a conductor structure 30 (see Figure 5 and Figure 6). Accordingly, the sensor unit 20 can be divided into two longitudinal bars 32a, 32b that are opposite to each other and a crossbar 32c that connects the two longitudinal bars 32a, 32b. Here, each detection section 20a is part of such a crossbar 32c. In particular, the connecting section 20b or parts of the connecting section 20b (which are also parts of such a crossbar 32c) can be narrower at least in the x-direction, especially in the region of the detection area 20a and in the region of the longitudinal bars 32a, 32b. In particular, the longitudinal bars 32a, 32b have a greater width in the y-direction than the connecting section 20b (which is also part of the crossbar 32c) in the x-direction. This design is aimed at a simple break or simple cut of the sensor unit 20 in the region of the crossbar 32c, especially in the connecting region 20b that is different from the detection area 20a.

[0059] Figure 2 Show Figure 1 Schematic diagram of the battery assembly 10 in the now triggered state of the sensor unit 20. In this case, the gas 26 escapes from the openable cell exhaust opening 16 of the cell 12, for example. Due to the gas pressure generated by the gas 26 impinging on the detection section 20a of the sensor unit 20, the sensor unit 20 breaks in the region of the predetermined breaking point 28 corresponding to the relevant detection area 20a. As a result, the sensor unit 20 and in particular the electrical conductor 22 are now interrupted in the region of the predetermined breaking point 28. This can now be advantageously used to detect the gas escape 26 by evaluating the above-mentioned at least one electrical variable of the conductor 22, as will be described in detail later.

[0060] Furthermore, it is possible to use not only the gas pressure caused by the impact of the gas 26 on the detection section 20a but also the temperature of the escaping hot gas flow 26 for decomposing the sensor unit 20, as shown in the example of Figure 3 As shown in .

[0061] Here, Figure 3 A battery assembly 10 according to another embodiment of the invention is shown. The battery assembly can in particular be constructed as described above, except for the differences described below. The example further illustrates how gas 26 escapes from the battery cell 12 and how it impinges on the detection area 20a, which is arranged directly below the openable battery cell exhaust opening 16 in the z-direction shown. In this case, the escape and the gas flow 26 do not lead to a fracture of the sensor unit 20 in the area of ​​the predetermined fracture site 28, but rather to a melting of the sensor unit 20 in the area of ​​the detection section 20a. Accordingly, in this example, the sensor unit 20 does not necessarily have to be constructed according to Figure 1 and Figure 2The predetermined breaking point 28 described is not described, but this is still possible. If, for example, the force is insufficient to provide a cut of the conductor 22, for example due to too low a gas pressure, then, if present, the thermal effect of the escaping gas 26 can also be used additionally to cause damage to the conductor 22, which in this example is the melting of the sensor unit 20 together with the conductor 22 in the region of the detection region 20a. By this melting, the conductor 22 is also interrupted at the same time, which can again be detected by measurement technology, so that the gas escape 26 can be detected.

[0062] Safety can thus be additionally increased, since the described battery assembly 10 and in particular the described sensor device 18 make it possible to use the gas pressure of the gas 26 escaping from its cells 12 and the temperature of the gas 26 for triggering the sensor unit 20. If the outgassing of the cells 12 is to take place, for example, in the form of cold outgassing, this can be detected, for example, by pressure-induced damage to the sensor unit 20. If the outgassing gas pressure of the hot outgassing cells 12 is too low, the outgassing can be detected by melting of the sensor unit 20. Thus, in many different situations, gas outgassing can be detected reliably and in particular also in advance.

[0063] exist Figures 1 to 3 In the example shown in FIG. 1 , the sensor unit 20 is also spaced apart from the cell exhaust opening 16 at least in the z direction shown. The spacing is Figure 1 and Figure 3 d and is preferably in the millimeter range, particularly preferably in the single-digit millimeter range. Therefore, the sensor unit 20 can be advantageously designed in such a way that no physical contact with the battery cell exhaust opening 16 is required. Support can be provided relative to the battery module 14 by the longitudinal bars 32a and 32b. In other words, the sensor unit 20 can be arranged on the battery module 14 and the battery cell 12 as shown, which is included in the module 14, but has a certain spacing d from the corresponding battery cell exhaust opening 16 located thereon in the area of ​​the detection section 20a. As a result, even in the case of a wider design of the surface F of the detection section 20a, it can be additionally prevented that the gas escape 26 is hindered or obstructed.

[0064] Figure 4A schematic diagram of a battery assembly 10 according to another embodiment of the present invention is shown. The battery assembly also includes a sensor device 18 having a sensor unit 20. In addition, the battery assembly 10 can also be constructed as described above, with only the differences described below. In this example, the sensor unit 20 is arranged directly on the battery cell exhaust opening 16. However, due to the provision of an electrically insulating bracket 24 in which the conductor 22 is embedded, there is still a certain spacing between the conductor 22 and the battery cell exhaust opening 16, although it is very small. Therefore, there is no direct contact between the conductor 22 and the battery cell exhaust opening 16. This enables a slightly flatter structural form along the z direction.

[0065] Figure 5 According to one embodiment of the present invention, a schematic diagram of a sensor unit 20 for a battery assembly 10 is shown, which is designed in the form of a conductor structure 30. In this case, the sensor unit 20 can be configured as follows: Figure 1 and Figure 2 32c. In this example, the electrical conductor 22 is designed as a parallel circuit, for example a parallel circuit of the individual line resistances of the beam 32c. In other words, the electrical conductor 22 is provided in the form of a conductor assembly or conductor line assembly 22, which forms such a parallel circuit. The individual load resistors corresponding to the respective beams 32c can be identical, for example. If damage 34 of the sensor unit 20 occurs in the region of one of the beams 32c, for example a break at the predetermined break point 28, the total resistance of the entire assembly is thereby changed. In particular, the following formula applies to the total resistance R G :

[0066] R G =R / N.

[0067] Here, R is the individual resistance corresponding to the respective crossbar 32c, for example the conductor resistance of this crossbar 32c. Here, N is the number of undamaged, i.e. uncut crossbars 32c. It is assumed here that the resistance of the individual crossbars 32c is of the same magnitude. If this is not the case, the calculation would be slightly more complicated, but a crossbar break or cut could be detected in a completely similar manner. Thus, if a cut occurs in the region of one of the crossbars 32c of the conductor 22, the number N of uncut crossbars 32c changes accordingly, for example by 1. The total resistance R G In the case of the five beams shown and assuming a beam resistance R of 1 milliohm (mΩ), the total resistance R before the cell is disconnected is G is 0.2 milliohms, and the total resistance after the cell is disconnected is 0.25 milliohms accordingly. GThis change in the resistance of the conductor 22 can detect a cut in the area of ​​one of the crossbars 32c and thus a gas escape 26. In addition, this detection method can also determine the number of crossbars that have been cut based on the total resistance. Therefore, it is also possible to detect when more than just one cell 12 is disconnected based on the value of the total resistance. In particular, the number of cells 12 of the battery assembly 10 that are associated with such a gas escape 26 can be determined, for example, by the aforementioned measuring device.

[0068] A slightly simpler and preferred embodiment of the sensor unit 20 in the form of a conductor structure 30 is schematically shown in FIG. Figure 6 The sensor unit can in particular be as follows Figure 5 32c, a series circuit of individual conductor resistances of the beams 32c. If the conductor 22 breaks, for example, in the region of one of the beams 32c, for example in the region of the aforementioned predetermined breaking point 28, this results in a current interruption. This can be detected by the measuring device. This design is particularly simple. In addition, in this variant, the measurement accuracy is independent of the number of beams 32c. In other words, the number of possible beams 32c is not limited by the given measurement accuracy of the electrical variable for detecting the conductor 22.

[0069] Figure 7 According to another embodiment of the present invention, another possible design solution for a single crossbar 32c of a sensor unit 20 is shown. The conductor 22 can not only pass through the corresponding crossbar 32c of the sensor unit 20 once or any other section 20a, 20b, but also can pass through it several times, for example twice, as shown here in the form of a conductor loop 22c formed by the conductor 22. In this way, a series circuit corresponding to the individual line resistances of the individual crossbars 32c can also be provided in a simple manner, such as according to Figure 6 As described. In this case, a damage 34 of the conductor 22 in the region of the crossbar 32c is also shown, which has already resulted in two cuts of the conductor 22. However, it is also possible to detect a single cut, since this results in an interruption of the conductor 22. Therefore, in the case of a series circuit, it is not necessary to completely cut the crossbar 32c in order to detect a gas escape 26. For example, it is sufficient that the crossbar 32c is damaged in such a way that only one of the two sections 36a, 36b of the conductor 22 is damaged or cut. In this case, the other of the two sections 36a, 36b can remain intact.

[0070] Figure 8According to another embodiment of the present invention, a schematic cross-sectional view of a battery assembly 10 is shown. The battery assembly can also be designed as described above, except for the differences described below: On the one hand, additional components of the battery assembly 10 are shown here, which can also be arranged in the above-mentioned embodiments. In particular, this involves a housing component 38 arranged below the battery module 14 or the battery cell 12 in the z-direction, which is designed in this example as a cooling plate 40 with two cooling channels 42. Here, the cooling channel 42 is arranged in the following position, which is not directly opposite to the openable battery cell exhaust opening 16 of the battery cell 12 of the battery module 14 in the battery cell direction. More precisely, the cooling channel 42 extends to the left and right of the battery cell exhaust area in the y-direction shown.

[0071] In this example, the sensor unit 20 is arranged on a cooling plate 40 having a cooling channel 42. The cooling plate 40 can be arranged on the module 14 by means of a heat-conducting glue or a caulking agent. The sensor unit 20 can be arranged in a sealed manner, for example, bonded to the cooling plate 40 by means of a seal 45. Optionally, the adhesive used for bonding can also simultaneously assume the function of the seal 45, or the adhesive can be the seal 45, or the seal 45 can be additionally provided. This also applies when the support 24 is designed as at least one support film, as described below.

[0072] The cooling plate 40 has a recess in which or below it in the z direction the sensor unit is arranged, in particular on the cooling plate 40 itself. The sensor unit 20 in turn comprises a conductor structure, wherein in this example the conductor structure is realized only by the electrical conductor 22 comprised by the sensor unit 20, but not by the support 24, which in this example is designed as a continuous support plate 24a. Alternatively, the support 24 can also be designed similarly as at least one support film. The electrical conductor 22 can be arranged on the support film or can also be laminated between two support films. In addition, at least one support film can be flat. Such a support film can be very thin, for example, its thickness is a maximum of a few millimeters, or a maximum of 1 millimeter or less than 1 millimeter. At least one support film together with the conductor 22 arranged thereon or therein can be fixed in the battery assembly 10 by bonding, for example, by bonding to the lower side 12a of at least one battery cell 12 or on the side of the cooling plate 40 opposite to the at least one battery cell 12, for example, in the following area, bonding to the cooling plate 40 itself, in which area Figure 8 The seal 45 is shown in FIG.

[0073] Here, Fig. 9 Another exemplary embodiment according to the present invention is again shown in a top view of the battery assembly 10 from below or similarly. Figure 8Schematic diagram of the battery assembly 10 in, according to this embodiment, the bracket 24 is designed as a support film. Although the electrical conductor 22 is also shown here, the electrical conductor can still be completely embedded in the electrically insulating material of the bracket 24. In this example, the sensor unit 20 includes a plurality of preset breaking locations 28. In this example, the preset breaking location is designed as a preset breaking line 28a and, for example, defines the corresponding aforementioned detection area 20a of the sensor unit 20 or surrounds the detection area, wherein such a detection area 20a is provided for each battery cell exhaust opening 16. The preset breaking location 28 or the preset breaking line can be designed as a material weakening portion, a cut portion, a perforation portion, a puncture portion, etc. Preferably, the preset breaking location 28 or the preset breaking line 28a is constructed in the following manner, that is, the sensor unit is not completely penetrated in the z direction. As a result, in particular, the battery cell exhaust opening 16 is significantly better protected to avoid environmental influences, and dirt or liquids, etc. can be prevented from entering the remaining gap 46.

[0074] Moreover, in this example, the corresponding detection section 20a is at a certain distance d from the cell exhaust opening 16. If the support 24 is designed as a plastic plate 24a, a frame 24b can be provided by the plastic plate 24a, which extends in the region where the longitudinal section 22d extending in the x direction of the conductor track component 22 is also provided. The support 24 can also be designed as a support film, which is bonded to the cooling plate 40, for example, along the outer contour of the support film in the shape of a surrounding frame.

[0075] In this example, the detection of damage to the sensor unit 20 can be performed, for example, according to Figure 5 It is also conceivable that, by alternative routing and design of the conductor 22, a series circuit is provided only in the closed plastic plate 24a and similarly realized, as according to Figure 6 As described.

[0076] In general, these examples show how to provide a sensor for cell exhaust or a sensor system for disconnecting a cell module. Here, this idea includes a feasible solution for identifying this situation using a resistance measurement loop. For this purpose, a (plastic) frame or a (plastic) plate or a (plastic) film can be installed on the cell side or module side with an exhaust opening, which surrounds the electrical conductor. The conductor passes through the exhaust area of ​​the cell and the plastic frame forms a planar area at the same time. When the cell is exhausted, pressure acts on the cell with the conductor and thus causes the thin connection with the frame to tear off, which can also be constructed with a preset breaking position or designed as a preset breaking position by its thin design. The conductor can also be cut off or burned by the hot exhaust flow. Alternatively, the conductor can be arranged in a plastic plate with a preset breaking position, which is fixed to the module or cell and seals the exhaust opening to the outside. The advantage of the present invention is that the frame or plate can be simply applied and adjusted, and the interruption of the wire can be achieved independently of temperature. In addition, some cell manufacturers do not allow components to be arranged directly on the exhaust opening.

Claims

1. A battery assembly (10) comprising a sensor device (18) for detecting gas evolution (26) of at least one battery cell (12) of the battery assembly (10), - the battery assembly comprises at least one battery cell (12), wherein the at least one battery cell has an openable battery cell exhaust opening (16), -in, A sensor device (18) for detecting a gas escape (26) comprises a sensor unit (20) having an electrical conductor (22) to which a test voltage can be applied. wherein the sensor unit (20) is arranged in such a way that the gas (26) escaping from the cell exhaust opening (16) impinges on the sensor unit (20), - wherein the electrical conductor (22) can be damaged by gas (26) flowing out of the exhaust opening (16) of the battery cell, It is characterized in that The sensor unit (20) is designed in such a way that the electrical line (22) can be damaged by the outflow pressure of the gas (26) escaping from the cell vent opening (16) in the event of a thermal runaway of the cell (12).

2. The battery assembly (10) according to claim 1, It is characterized in that The electrical conductor (22) is arranged to be spaced apart from the openable battery cell exhaust opening (16) by a distance (d), and / or the sensor unit (20) has a bracket (24) made of a non-conductive material, on which the electrical conductor (22) is arranged and / or the electrical conductor (22) is embedded in the bracket, in particular, wherein the bracket (24) provides a frame and / or is designed as a support plate (24a) and / or a support film.

3. The battery assembly (10) according to claim 1, It is characterized in that A free space (46), in particular a gap (46), is provided between the battery cell exhaust opening (16) and the sensor unit (20) along a first direction (z).

4. A battery assembly (10) according to any one of the preceding claims, It is characterized in that The sensor device (18) is designed to detect damage to the line (22) to which the test voltage is applied in dependence on a measured electrical variable corresponding to the line (22) and to detect a gas escape (26) in dependence on the detected damage to the line (22).

5. The battery assembly (10) according to any one of the preceding claims, It is characterized in that The sensor unit (20) has a predetermined breaking point (28), wherein the conductor (22) can be damaged by damage or breaking of the sensor unit (20) at the predetermined breaking point (28), in particular wherein the predetermined breaking point (28) is constructed in the support (24).

6. A battery assembly (10) according to any one of the preceding claims, It is characterized in that The sensor unit (20) has a detection section (20a) which is directly opposite to the cell exhaust opening (16) of the cell (12) in the gas escape direction (z), wherein the support (24) has a support surface (F) at least in the detection section (20a), which is wider than the conductor surface of the electrical wire (22) in a second direction (x).

7. A battery assembly (10) according to any one of the preceding claims, It is characterized in that The battery assembly (10) comprises a plurality of battery cells (12) with corresponding openable battery cell vent openings (16), - wherein the sensor unit (20) comprises a plurality of detection sections (20a), - wherein each detection section (20a) corresponds to exactly one cell exhaust opening (16), - wherein the sensor unit (20) has a plurality of predetermined breaking locations (28), - wherein each detection segment (20a) is provided with at least one of the predetermined breaking points (28), the at least one predetermined breaking point being arranged in particular in an edge region of the detection segment (20a) and / or adjacent to the detection segment (20a).

8. A battery assembly (10) according to any one of the preceding claims, It is characterized in that The sensor unit (20) comprises a plurality of connecting sections (20b), wherein the respective detection sections (20a) are connected to each other via the plurality of connecting sections (20b), wherein the respective connecting section (20b) is narrower than the respective detection section (20a) in a second direction (x), and in particular wherein a conductor structure (30) is formed by the connecting sections (20b) and the detection sections (20a), wherein the conductor structure comprises two opposing longitudinal rods (32a, 32b) and a plurality of cross beams (32c) connecting the two longitudinal rods (32a, 32b), wherein each cross beam (32c) comprises a detection section (20a).

9. A battery assembly (10) according to any one of the preceding claims, It is characterized in that The battery assembly (10) comprises a shell component (38), in particular a cooling plate (40), wherein the at least one battery cell (12) comprises a first battery cell side (12a) having a first area, a second area and a third area, wherein an openable battery cell exhaust opening (16) is arranged in the second area, and the second area is arranged between the first area and the third area along a third direction (y), wherein the first area and the third area are respectively arranged on the shell component through an interface material, wherein a free area is provided below the second area in a first direction (z), a sensor unit (20) is arranged in the free area, and the free area is located between two sections of the shell component (38) along the third direction (y).

10. A method for detecting gas evolution (26) of at least one battery cell (12), the at least one battery cell having an openable battery cell vent opening (16), -in, A sensor unit (20) having an electrical line (22) to which a test voltage is applied is used for detecting a gas escape (26). - wherein the gas (26) escaping from the cell exhaust opening (16) impinges on the sensor unit (20) and damages the wire (22), - wherein the gas escape (26) is detected by detecting damage to the electrical conductor (22), It is characterized in that The electrical conductor (22) is damaged by the outflow pressure of the gas (26) escaping from the battery cell exhaust opening (16).

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