Battery assembly, motor vehicle and method for detecting gas escape of cell

Abstract

The invention relates to a battery assembly having a sensor device for detecting a gas escape of at least one cell having a releasable cell vent opening (26), comprising a gas outlet channel (22), the device has at least one gas inlet region (30), a gas outlet region (36) and at least one flow path (34) from the at least one gas inlet region (30) to the at least one gas outlet region (36). The sensor device has at least one sensor element (46) which protrudes into the flow path (34) and which has an electrical conductor (49) which can be damaged by a gas (24) flowing through the gas discharge channel (22) along the at least one flow path (34) and which escapes from the at least one cell, the sensor device is designed to detect a damage to the conductor (49) to which the test voltage (U) is applied on the basis of the measured electrical variable (I, R) associated with the conductor (49) and to detect a gas escape on the basis of the detected damage to the conductor (49).

Description

Technical Field

[0001] The present invention relates to a battery assembly having a sensor device for detecting gas leakage from at least one battery cell of the battery assembly, wherein the battery assembly comprises: at least one battery cell having a releasable battery cell exhaust opening; a gas outlet channel / gas discharge channel, the gas outlet channel having at least one gas inlet region capable of introducing gas escaping from the battery cell exhaust opening into the gas outlet channel, at least one gas outlet region, and at least one flow path from the at least one gas inlet region to the at least one gas outlet region. In addition, the present invention also relates to a motor vehicle having such a battery assembly and a method for detecting gas leakage from at least one battery cell. Background Art

[0002] In particular, cells for high-voltage battery systems of motor vehicles may generate internal pressure due to various fault reasons, and such cells usually have a weakening portion provided for this purpose in the housing, which is referred to here as a releasable cell exhaust opening, in order to prevent unlimited explosion. Cell exhaust indicates a possible serious fault in the battery and subsequent damage, up to system propagation. For this reason, in order to warn the user and activate safety functions in the high-voltage battery, it is advantageous to be able to identify such fault functions. In order to discharge the gas escaping from the cell, the gas can be introduced into a gas outlet channel, which, for example, leads to the surrounding environment of the motor vehicle. Such a gas outlet channel can also be called an exhaust channel.

[0003] DE 10 2019 219 593 A1 describes an electrochemical storage unit having a plurality of cells and a flow guiding element, which is connected to at least one of the plurality of electrochemical cells and comprises a circuit board element, on the side of the circuit board element facing the cell a flow guiding element or a flow channel for guiding a fluid escaping from the cell is arranged. When the circuit board element breaks at a predetermined breaking point, an electrical separation of the connecting elements that electrically connect the cells occurs.

[0004] Furthermore, DE 10 2020 004 558 A1 describes a device for detecting a pressure drop in the event of a bursting element in the housing of a battery having at least one cell module comprising a plurality of cells, wherein a cavity is provided in the housing and is closed relative to the remaining internal volume of the housing by means of a movable cover. Furthermore, an electrical conductor having a predetermined breaking point extends through the cover. Furthermore, the cavity has a pressure equalization hole for achieving pressure equalization of the cavity with the remaining internal volume of the housing. In the event of a slow pressure increase due to cell exhaust, a corresponding pressure equalization is performed via the pressure equalization hole. In the event of a sudden opening of the bursting element in the housing and a sudden pressure drop caused thereby, the cover opens, whereby the electrical conductor is torn apart. The pressure drop can thus be detected.

[0005] EP 4 009 412 A1 describes an energy storage device for a rail vehicle having two battery modules, which are arranged side by side and connected to each other, wherein the battery modules are connected to a signal generator via a safety device, by means of which a signal for a fire alarm device can be generated. In this case, the battery cells of the battery module can each have an overvoltage opening. A clip-shaped retaining member is arranged on the corresponding overvoltage opening, in which a signal generator is accommodated, which can be designed in the form of an electrical conductor. Therefore, the signal generator in the form of an electrical conductor extends through all overvoltage openings of the battery cells. In this case, the signal generator can be used as a fuse and can be used to generate a signal for a fire alarm device in the event of gas escape from the battery cell. Summary of the invention

[0006] It is therefore an object of the present invention to provide a battery assembly, a motor vehicle and a method which make it possible to detect the evolution of gas from at least one battery cell as simply as possible, in a space-efficient and reliable manner.

[0007] This object is achieved by a battery assembly, a motor vehicle 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.

[0008] The battery assembly according to the invention comprises a sensor device for detecting gas emission from at least one battery cell of the battery assembly, wherein the battery assembly comprises: at least one battery cell, the at least one battery cell comprising a releasable battery cell exhaust opening; a gas discharge channel, the gas discharge channel comprising at least one gas inlet region, at least one gas outlet region, and at least one flow path from the at least one gas inlet region to the at least one gas outlet region, through which gas escaping from the battery cell exhaust opening can be introduced into the gas discharge channel. The sensor device comprises at least one sensor element arranged in the gas discharge channel and extending into the flow path, the at least one sensor element comprising an electrical conductor to which a test voltage can be applied, wherein the sensor element is designed such that the electrical conductor can be damaged by gas escaping from the at least one battery cell and flowing through the gas discharge channel along the at least one flow path, and wherein the sensor device is designed to detect damage to the conductor to which the test voltage is applied based on a measured electrical variable assigned to the conductor, and to detect gas emission based on the detected damage to the conductor.

[0009] The invention is based on the knowledge that a gas outlet channel can be used for gas outlet by a plurality of cells of a battery. In other words, a plurality of cells can be connected to such a gas outlet channel so that the gas escaping from each cell can be introduced into the gas outlet channel and is discharged through the gas outlet channel. In addition, the invention is based on the knowledge that the gas flow formed in such an outlet channel during gas outlet can be used to cause damage to the corresponding sensor element, which damage can be simply detected by means of an electrical conductor to which a test voltage can be applied, so that gas escape can be detected simply and effectively. In particular, in this case, it is not necessary to provide a sensor element for each of the plurality of cells, but a sensor element can monitor the gas escape of a plurality of cells at the same time, and in particular, the sensor element does not need to extend through all cells or need not be designed in an extended manner. Therefore, the sensor element can be positioned at any position in the flow path. Therefore, the local positioning of such a sensor element anywhere in the gas outlet path is sufficient for detecting gas escaping from any cell. Therefore, the gas escape of the cell can be detected in a particularly reliable, cost-effective, space-saving and effective manner.

[0010] Here, a gas discharge channel is to be understood in particular as a channel which is designed to deflect and channelize the gas in a targeted manner. In other words, such a gas discharge channel can include a channel wall or optionally also a gas guiding element arranged in the channel, through which the gas to be discharged can be channeled and guided, that is, such a channel wall prevents the gas to be discharged from entering other areas in the battery housing or in the motor vehicle where the gas should not enter, for example.

[0011] Here, at least one battery cell is constructed with a battery cell exhaust opening, more precisely a releasable battery cell exhaust opening. This means that the battery cell exhaust opening is closed under normal circumstances and is only released, i.e. opened, under certain conditions. The condition is preferably that the internal pressure of the battery cell exceeds a certain threshold value. The releasable battery cell exhaust opening is preferably designed as a passive battery cell exhaust opening, which opens pressure-dependently and passively, i.e. opens in relation to the internal pressure of the battery cell. The battery cell exhaust opening can be designed, for example, as an overpressure valve, a bursting membrane or other local material weakening of the battery cell housing of the battery cell.

[0012] In order to introduce the gas escaping from the battery cell exhaust opening into the gas outlet channel, the battery cell exhaust opening is preferably oriented toward at least one inlet area of ​​the gas outlet channel. Here, the gas inlet area of ​​the gas outlet channel can be designed as a permanent opening in the gas outlet channel, and this battery cell exhaust opening is connected to the permanent opening, for example, directly arranged and adjacent to the permanent opening, and / or the inlet area can also be designed as a releasable opening in the gas outlet channel. The gas outlet channel can also be constructed with a local or larger area material weakening portion in the area of ​​at least one gas inlet area, for example, by covering with a film, so that the closure that closes the releasable opening can be destroyed by the escaping gas when the gas of the battery cell exhaust opening escapes, thereby releasing the gas inlet area in the gas outlet channel.

[0013] The gas inlet region can, for example, extend as a common gas inlet region across a plurality of cell exhaust openings of a plurality of cells of the battery assembly, or such a gas inlet region can be provided for each cell or its cell exhaust opening. This applies in particular when the battery assembly has a plurality of cells, as is preferred.

[0014] Therefore, the battery assembly may include one or preferably multiple cells. These cells may be designed as lithium-ion cells, for example. In addition, these cells may optionally form a battery module. A high-voltage battery may be provided, for example, by multiple cells.

[0015] The at least one gas outlet region can also be designed as described with respect to the gas inlet region, i.e., thus, for example, as a permanent opening or a releasable opening, for example as a bursting element or a pressure relief valve, etc. A plurality of separate gas outlet regions can also be provided, wherein the number of outlet regions can be selected independently of the number of gas inlet regions of the gas discharge channel.

[0016] The gas outlet passage can also be understood as a cavity-like space, or the gas outlet passage can include such a gas outlet space or such a gas outlet chamber. Such a gas outlet chamber can be located, for example, above or below a battery assembly or an assembly including a plurality of battery cells and can, for example, extend through all the battery cell exhaust openings of these battery cells. Such a gas outlet chamber can be defined by two opposing chamber walls surrounding the gas outlet space. The sensor element can be arranged in such a gas outlet chamber accordingly, in particular extending into the intermediate space defined by it and, for example, arranged on one of the two chamber walls.

[0017] The sensor device can also include a measuring device in addition to at least one sensor element to detect an electrical parameter assigned to the electrical conductor. In the simplest case, the electrical parameter can be current intensity and / or resistance. The measuring device can also be designed to apply a test voltage to the electrical conductor. The test voltage can be applied between the two lead-out contacts of the electrical conductor. In the undamaged state of the conductor, a current flowing through the electrical conductor is thus caused, which can be detected by the measuring device. In the case of wire damage, such as wire disconnection, the current is interrupted. This can also be detected by the measuring device. Thus, wire damage and thus gas escape can be detected. This can be achieved, for example, using a simple conductor loop. However, more complex measuring devices can also be considered, so that - for example, by a change in the wire resistance of the wire - for example, not only the disconnection of the wire can be determined, but also, for example, the only damage of the wire that is not disconnected from the electrical conductor can be determined. Accordingly, as an electrical parameter, the current intensity can not only or not exclusively be determined or detected, but other parameters, such as resistance, can also be determined or detected, for example.

[0018] The electric wire can be designed as an electric conductor. Here, the electric wire can be made completely of an electrically conductive material, preferably a metal. Here preferably, the electric wire itself does not have a sheath like a cable. The electric wire can be designed, for example, as a single conductive wire, in particular a litz wire.

[0019] The sensor device is preferably designed to detect gas escape when the following condition is met, i.e., damage to the conductor has been detected. Furthermore, the sensor device is preferably designed to detect damage to the conductor by detecting a predetermined change in a detected electrical variable of the conductor, for example, a drop in the value of the current intensity to zero. It is not necessary to detect the drop itself, but only to detect that the current no longer flows through the conductor, i.e., to detect a current intensity of 0 A when the test voltage is applied, which is sufficient to determine that the conductor is damaged. It is therefore correspondingly preferred to detect damage to the conductor to which the test voltage is applied based on the measured current intensity assigned to the conductor.

[0020] According to another advantageous embodiment of the invention, the sensor element has a preset breaking point, wherein the electrical conductor can be damaged by damage or breakage of the sensor element at the preset breaking point. The sensor element can in principle also be provided only by the electrical conductor itself, or the sensor element can include other components, as will be explained in detail later. In any case, damage or breakage of the sensor element in the region of the preset breaking point should lead to corresponding damage or even breakage of the conductor. The preset breaking point enables significantly simpler damage to the sensor element and thus to the electrical conductor. Gas escape can therefore be detected particularly reliably, and a small gas flow is already sufficient to be able to cause damage to the sensor element.

[0021] In principle, the heat generated by the gas escape can be used to damage the sensor element and the electrical conductors. However, there is also so-called cold exhaust in the cell, according to which the releasable cell exhaust opening of the cell is opened and pressure equalization with the surroundings occurs, but no hot gas escapes from the cell. Accordingly, it is preferred that the pressure effect of the escaping gas is used to exert pressure on the sensor element.

[0022] Accordingly, another very advantageous design of the present invention is that the sensor element is designed in such a way that the sensor element can be damaged at a predetermined breaking point due to the pressure effect on the sensor element generated or can be generated by the gas escaping from at least one battery cell and flowing along the flow path. Therefore, the sensor element can be designed so that the sensor element is still damaged, for example, broken or torn off even in the case of cold gas flowing along the flow path. In addition, this can also make it possible to arrange the sensor element very close to the gas outlet area of ​​the gas outlet path, in which case other measures or components can also be integrated upstream in the gas outlet path to cause gas cooling and particle separation. The advantage is that the gas can be cooled along the flow path and can be discharged from the gas outlet opening, that is, the gas outlet area, from the gas outlet channel as a relatively cold gas, thereby minimizing the danger to the surrounding environment and, in particular, preventing the gas from igniting spontaneously when escaping into the surrounding environment. Therefore, the advantage of "using the pressure effect of the gas" is that there is more flexibility in the positioning of at least one sensor element, because the sensor element does not have to be positioned in an area where the gas to be discharged is still very hot. In addition, gas escape can be detected in the case of cold exhaust gas. Furthermore, the sensor element can thereby be designed particularly simply, i.e., it can be reliably protected from damage by the pressure effects of the gas flowing along the flow path, since the sensor element can for this purpose, for example, be simply constructed with an area that is large enough to provide a corresponding flow resistance and with a corresponding preset breaking point, which bends or yields when a desired or predetermined flow pressure is exceeded and correspondingly leads to damage, or a break or tearing off, of a part of the sensor element.

[0023] In another very advantageous design of the present invention, the sensor element has a carrier, in particular containing plastic, on which an electric conductor is arranged and / or in which an electric conductor is embedded. This has the advantage that the conductor can be guided and supported more simply in terms of its positioning. In addition, the conductor can be electrically insulated to the outside in a simple manner at the same time. The carrier can be designed as a small plastic sheet or can also be designed as a plastic film or two plastic films, between which the conductor is arranged or laminated. In addition, it is preferred that the carrier extends into the flow path together with the conductor, in particular, wherein the preset breaking position is at least designed as a part of the carrier. In addition, the carrier can realize a simple fixation of the wire or the electric conductor. In addition, when using an additional carrier, that is, when using a carrier in addition to the conductor, a particularly thin stranded wire can be used as an electric conductor with a very small conductor cross section, but assembly can still be realized simply, and there is no need to worry about the damage of such a thin conductor as a conductor during normal operation. This thin design of the electric conductor makes damage easy in the case of gas escape. Nevertheless, sufficient stability can still be provided by the carrier during installation and normal operation. Furthermore, such thin wires do not necessarily have to have a predetermined breaking point, and the wire itself does not have to provide a large area for providing a high flow resistance. It is therefore sufficient to integrate such a predetermined breaking point, for example as a cutout or groove, into a carrier that supports or stabilizes the wire.

[0024] In addition, by using a carrier, the sensor element can be advantageously dimensioned with the greatest possible flow resistance with respect to the flow path, without having to dimension the electrical conductor accordingly. Therefore, another very advantageous design of the present invention is that the carrier is designed as a small thin plate or includes a small thin plate, which has a length and a width, the small thin plate extends into the flow path in the direction of its length, its width is greater than the conductor width of the electrical conductor in a direction perpendicular to the length of the small thin plate, and its surface is arranged to form an angle not equal to zero, preferably a right angle, with the flow direction of the gas flowing along the flow path. Such a small thin plate can be formed in a simple manner over a large area, so that when the small thin plate extends into the flow path and is, for example, oriented perpendicularly to the flow path or perpendicularly to the air flow flowing through the flow path in the case of exhaust, a very large flow resistance is thus provided, which flow resistance, in combination with the predetermined breaking point, leads to damage, tearing or disconnection of the sensor element in the region of the predetermined breaking point, and thus also leads to damage to the electrical conductor, especially disconnection or tearing of the electrical conductor. The carrier can also include two such small thin plates, for example in the form of films, with the electrical conductor embedded between the films. The electrical conductors can also be embedded in such films or such thin plates by means of an injection molding process.

[0025] It is also very advantageous that the carrier has a first end and a second end opposite in a first direction, wherein the carrier is arranged on the wall of the gas outlet channel only with the first end, in particular wherein the preset breaking point is arranged closer to the first end than the second end. The first direction can be defined, for example, in the direction of the length of the carrier. Therefore, the carrier is only fixed on one side together with the electrical conductor. The sensor element extends into the flow path with the other end. This enables particularly easy tearing or bending of the sensor element along the gas flow through the flow path, because the carrier and therefore the sensor element are not fixed on both sides and are thus stable. It is also very advantageous that the preset breaking point is arranged closer to the first end than the second end, because in this case the torque acting on the preset breaking point is significantly greater due to the lever effect in the case of gas flow, which simplifies damage or tearing of the sensor element in the area of ​​the preset breaking point.

[0026] In another very advantageous embodiment of the invention, the electrical conductor is laid on the carrier in the form of a loop from the first end in the direction of the second end over the predetermined breaking point. The electrical conductor can, for example, be guided from the first end of the carrier in the direction of the second end and from there back to the first end. In this case, the electrical conductor can accordingly cross the predetermined breaking point or a predetermined breaking line extending in the direction of the width of the carrier twice. The tearing off of the sensor element along the predetermined breaking line results in the electrical conductor being cut twice or in the lower part of the conductor loop being torn off.

[0027] Here, the electric wire does not necessarily end at the first end of the carrier with its two conductor ends, but can be guided through the first end of the carrier, for example, until it is guided to the measuring device of the sensor device. The measuring device can be located at any other position. In particular, the measuring device can also be located outside the gas outlet channel. Here, the carrier can also be guided to the measuring device together with the wire. In this case, the first end of the carrier can be understood as the first end of the part of the carrier located in the gas outlet channel. The electric wire can be guided from the inner space of the gas outlet channel to the area outside the gas outlet channel with its two conductor ends until it is guided to the measuring device, and the carrier can optionally also extend to the measuring device, so as to stabilize the wire and / or electrically insulate it to the outside.

[0028] According to another very advantageous design of the present invention, the battery assembly includes a plurality of battery cells, each of which has a releasable battery cell exhaust opening, wherein the gas outlet channel is connected to the battery cell exhaust opening in the following manner, that is, the gas escaping from each battery cell exhaust opening can be introduced into the gas outlet channel through at least one gas inlet area. Therefore, the gas outlet channel is a common gas outlet channel, which can be used to simultaneously guide the gas of multiple battery cells. This does not mean that the gas must escape from each battery cell at the same time. This situation should be understood in particular that the gas escaping from the battery cell is introduced into the same gas outlet channel, regardless of which battery cell of the multiple battery cells included in the battery assembly the gas escapes from.

[0029] This has the significant advantage that, for example, only one sensor element or at least a smaller number of sensor elements is sufficient for detecting the gas escape, regardless of which battery cell it escapes from. Therefore, the battery assembly preferably comprises fewer sensor elements than battery cells, in particular fewer sensor elements by at least an order of magnitude, preferably a single digit number of sensor elements, for example only one, two, three, four or five.

[0030] If the gas discharge channel comprises, for example, a plurality of different flow paths which differ at least in sections in their path guidance, such a sensor element can be arranged in each gas discharge path and / or in spatially different sections. If a plurality of sensor elements are designed as part of a battery assembly, these sensor elements can be connected or coupled to a common measuring device of the sensor device.

[0031] In another very advantageous embodiment of the invention, the battery assembly has a housing in which at least one battery cell is arranged, wherein the housing comprises a housing wall, in particular a housing bottom, wherein the battery assembly has a plate, in particular an underbody protection device, outside the housing and opposite to the housing wall, wherein the housing wall and the plate form the wall of the gas discharge channel, the flow path extends through the intermediate space between the housing wall and the plate, and wherein the sensor element extends into the intermediate space. As described above, the gas discharge channel can be defined by two channel walls provided by the housing wall of the battery housing and the plate opposite to the housing wall. It is particularly advantageous that the housing wall forms the housing bottom of the battery housing and the plate forms the underbody protection device for a motor vehicle, in particular the underbody protection device of a motor vehicle in which the battery assembly is used. This allows, on the one hand, a very advantageous discharge of gas downward from the battery and thus away from the passenger compartment of the motor vehicle. In addition, the intermediate space between the underbody protection device of the motor vehicle and the housing bottom of the battery can therefore also be used as a gas discharge channel in a very space-efficient manner. In addition, the gas discharge channel can thus extend substantially parallel to the housing bottom over the entire surface of the battery, thereby providing, for example, a very large space for gas cooling measures and particle separation. The housing wall and the plate can be delimited laterally by the surrounding side wall. Accordingly, the gas outlet channel can be implemented in a fluid-tight manner except for the provided, releasable inlet opening and outlet opening. This prevents the escape of undesirable gas at other positions outside at least one gas outlet area. For example, the gas can also be guided through other structures in the gas outlet channel and turned in a targeted manner on one or more gas outlet paths. At least one sensor element can be arranged in this case so that at least one sensor element extends into this gas outlet path. It is particularly advantageous that the sensor element is connected or arranged and / or fixed to one of the walls, i.e., either the housing wall or the plate, on one side, i.e., only with one end (as described above). It is particularly preferred that the sensor element is arranged on the housing wall. This can make the measuring device of the sensor device arranged outside the gas outlet channel and the wire guide from the sensor element to the measuring device be particularly effectively designed.

[0032] The measuring device can be designed to send a signal based on the detection of gas escape, for example, send a signal when gas escape is detected, warn the user based on the signal and / or take predetermined response measures, such as increasing the cooling power of the cooling device for cooling the battery cells, disconnecting the high-voltage system of the motor vehicle, preventing the motor vehicle from starting or continuing to drive, preventing or interrupting the charging process for charging the battery cells, etc.

[0033] The invention furthermore relates to a motor vehicle having a battery assembly according to the invention or one of its embodiments.

[0034] 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.

[0035] The present invention also relates to a method for detecting gas emission from at least one battery cell of a battery assembly, wherein gas escaping from a battery cell exhaust opening of at least one battery cell is introduced into a gas outlet channel of the battery assembly via at least one gas inlet region of a gas outlet channel, is guided from the at least one gas inlet region to at least one gas outlet region of the gas outlet channel via the gas outlet channel along at least one flow path, and is discharged from the gas outlet channel via the at least one gas outlet region. Here, a sensor device of the battery assembly has at least one sensor element arranged in the gas outlet channel and extending into the flow path, the at least one sensor element comprising an electrical conductor to which a test voltage is applied, wherein the electrical conductor is and / or can be damaged by gas flowing through the gas outlet channel along at least one flow path, and wherein the sensor device detects damage to the conductor to which the test voltage is applied based on a measured electrical variable assigned to the conductor and detects gas emission based on the detected damage to the conductor.

[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] The measuring device may be part of a control device for a motor vehicle. The control device may have a data processing device or a processor device, which is configured to execute an embodiment of the method according to the present invention. For this purpose, the processor device may have at least one microprocessor and / or at least one microcontroller and / or at least one FPGA (field programmable gate array) and / or at least one DSP (digital signal processor). As a microprocessor, in particular, a CPU (central processing unit), a GPU (graphics processing unit) or an NPU (neural network processing unit) can be used respectively. In addition, the processor device may have a program code, which is configured to execute an embodiment of the method according to the present invention when it is run by the processor device. The program code can be stored in a data memory of the processor device. The processor device can be based on at least one circuit board and / or at least one SoC (system on chip), for example.

[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 present invention also includes combinations of features from the described embodiments. Therefore, the present invention also includes implementations that each have a combination of features from a plurality of non-mutually exclusive described embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] The embodiments of the present invention are described below. As shown in the figure:

[0041] Figure 1 A schematic cross-sectional view of a battery assembly is shown according to an embodiment of the present invention;

[0042] Figure 2 According to an embodiment of the present invention, Figure 1 A schematic cross-sectional view of a portion of a battery assembly before a sensor element for detecting gas escape is damaged;

[0043] Figure 3 According to an embodiment of the present invention, Figure 2 A schematic diagram of a portion of a battery assembly after a sensor element is damaged;

[0044] Figure 4 A schematic cross-sectional view of a battery assembly is shown according to another embodiment of the present invention; and

[0045] Figure 5 A schematic perspective view of a gas removal channel for a battery assembly according to an embodiment of the present invention is shown. DETAILED DESCRIPTION

[0046] Figure 1A schematic cross-sectional view of a battery assembly 10 is shown according to an embodiment of the present invention. The battery assembly includes a plurality of battery cells 12, which are provided in the form of a battery cell stack 14. This means that the battery cells 12 are arranged side by side in a stacking direction, wherein the stacking direction corresponds to the x-direction of the coordinate system shown here. A battery cell separator element 16a may be provided between the battery cells 12. In addition, such a battery cell stack 14 may be divided into a plurality of battery cell groups in a stacking direction by partition walls 16b in a battery housing 18 (where only the housing bottom 20 is shown here). In addition, the battery assembly 10 has a gas outlet channel 22 for outlet of gas 24 (shown here in the form of arrows 24) escaping from the battery cell 12 in the event of thermal runaway. For this purpose, the corresponding battery cell 12 has a releasable battery cell exhaust opening 26, which is in the form of, for example, a bursting membrane or a local material weakening of the battery cell housing, so as to enable controlled gas escape. Here, the battery cell 12 is arranged relative to the gas outlet channel 22 in such a manner that each releasable battery cell exhaust opening 26 faces directly toward the gas outlet channel 22. In particular, the cell 12 can also be directly connected to and adjoin the channel wall 28 of the gas discharge channel 22, which at the same time forms the housing bottom 20 of the battery housing 18. The channel wall 28 can accordingly have an inlet region 30, which corresponds spatially to the corresponding cell exhaust opening 26. The inlet region 30 can be designed in the simplest case as an opening or hole in the channel wall 28, the size of which corresponds to or is slightly larger than the size of the cell exhaust opening 26 arranged or adjoining there, respectively. These openings 30 can also be covered by a protective film (not shown), which is destroyed when the gas escapes and thus allows the gas to enter the channel interior 32. Therefore, the inlet region 30 can also be designed as a releasable opening and, for example, covered again with a bursting element, such as a protective film or the like. If gas escapes from the cell 12, the gas 24 escaping from the corresponding cell exhaust element 26 can be introduced directly into the interior 32 of the gas discharge channel 22 through the corresponding inlet region 30 of the gas discharge channel 22. In the interior 32 of the gas discharge channel 22, the gas 24 can be guided along a gas discharge path 34 to at least one outlet region in the form of an outlet 36 (see Figure 5 ), in particular, is guided to the surroundings 38 of the battery assembly 10 and in particular the motor vehicle in which the battery assembly 10 is used. Based on the preferred installation position in the motor vehicle, the z direction shown corresponds to the vehicle height direction. The x direction shown can be, for example, the longitudinal direction of the vehicle, and the y direction shown can be the transverse direction of the vehicle. Other arrangements are also conceivable. In addition, it is correspondingly advantageous that the second channel wall 40 of the gas outlet channel 22 is simultaneously provided by the underbody protection device 42 of such a motor vehicle.

[0047] The present invention and its embodiments now make it possible in a particularly advantageous manner to detect such a gas evolution of a cell 12 in a very simple, space-efficient, cost-effective and reliable manner. This is explained below.

[0048] For this purpose, the battery assembly 10 includes a sensor device 44 having a sensor element 46 and a measuring device 48, which is shown here only by dashed lines to illustrate that the measuring device 48 can in principle be arranged at any other location, in particular also remotely arranged and / or arranged outside the high-voltage battery 50 including the battery cell 12 and its housing 18.

[0049] The sensor element 46 comprises an electrical conductor 49 which is arranged on or embedded in a plastic carrier 50 of the sensor element 46 . In this case, the conductor 49 is designed in the form of a conductor loop and two conductor ends 52 are coupled to the measuring device 48 .

[0050] A voltage U can be applied to an electrical conductor 49 (hereinafter also referred to as conductor 49) by means of a measuring device 48. In addition, the measuring device 48 can permanently monitor or measure at repeated time intervals the current I flowing through the conductor 49. If there is no current I despite the application of the voltage U, this can be inferred as a conductor interruption of the electrical conductor 49 and accordingly also as a damage to the sensor element 46. Damage to the sensor element 46 can be used in an advantageous manner to detect gas escape from the battery cell 12. For this purpose, the sensor element 46 is designed here with a predetermined breaking point 54.

[0051] Figure 2 Again, it shows Figure 14 is a schematic detail view of a portion of a battery assembly 10 in FIG. 4 , wherein a sensor device 45 having a sensor element 46 is shown in an enlarged manner. The carrier 50 can be designed, for example, in the form of a small thin plate 56, which in particular extends into the flow path 34 together with the electrical conductor 49. Here, the small thin plate 56 has, for example, a first end 50a located in the gas outlet channel 22 and an opposite second end 50b, wherein only one of the two ends 50a, 50b is arranged on one of the channel walls 28, 42. In this example, the first end 50a is arranged on the housing bottom 20 as the channel wall 28, while the opposite end 50b is not fixed and extends loosely into the interior 32 of the gas outlet channel 22. Therefore, the second end 50b constitutes the loose end 50b of the carrier 50. The predetermined breaking point 54 is arranged as close as possible to the end of the carrier 50 fixed to one of the channel walls, here on the channel wall 28. The predetermined breaking point 54 can be arranged in the carrier 50 as a material weakening part, a slot part, a cutout, a perforation part or any combination thereof. The conductor 49 can also be optionally configured with such a material weakening part, a cutout, etc. to provide a predetermined breaking point, but this is not necessary. In particular, when the conductor 49 itself is designed to be very thin, for example, designed as a stranded wire, the above situation can be abandoned.

[0052] Furthermore, the carrier 50 can have a length L and a width B, wherein the length L in this example extends along or opposite to the z direction and the width is defined perpendicularly to the z direction, for example along the y direction, although the width B is shown here as a dimension along the x direction for better illustration. The small thin plate 56 is then preferably designed to be as thin as possible in a direction perpendicular to its length L and its width B, and a corresponding flow resistance can be provided by a correspondingly large width B (in particular a width B that is significantly larger than the width of the conductor 49). Accordingly, the small thin plate 56 is preferably arranged in the flow path 32 so that the gas 24 flowing along the flow path 32 impinges essentially perpendicularly on the small thin plate surface F, which is formed by its length L and its width B. Here, the small thin plate F is not necessarily rectangular, but can also be configured as a semicircle or an ellipse or any other geometric shape. The length and width can then refer to the maximum length and maximum width of the carrier 50. As a result, the gas pressure p generated when the gas 24 flows out of the battery cell can be advantageously used to damage, in particular tear off, the sensor element 46 in a targeted manner through this pressure action p, such as in Figure 3 Here, the tearing is realized in the region of the preset breaking point 54.

[0053] Therefore, the electrical line 49 is guided by a plate guided transversely to the flow direction as a carrier 50 with a predetermined breaking point 54. The plate 56 is broken at the predetermined breaking point 54 due to the gas pressure p and accordingly the conductor loop 51 formed by the conductor 49 is broken. This fault can be detected by the measuring device 48 by the described continuous current measurement or additionally or alternatively by a resistance measurement of the resistor R of the conductor 49.

[0054] Another advantageous secondary effect is that by measuring the electrical variables assigned to the conductor 49, such as the resistance R and / or the current I, it is also possible to measure the underbody deformation of the underbody protection device 40, for example due to external influences. Figure 2 This deformation of the bottom caused by the external force is indicated by arrow 58. The deformation of the underbody protection device 40 caused by this action 58 can also cause the plate 56 of the sensor element 46 to be squeezed from below and / or to be broken at the predetermined breaking point 54.

[0055] These two different fault situations can be distinguished by the measuring device 48, for example, simply in the following way, that is, to verify the gas escape, at least one other measurable parameter can be taken into account, such as the temperature of the battery cell 12, which can be detected by means of one or more temperature sensors distributed on the battery assembly 10. If the temperature is within a predetermined normal range, it can be concluded that the detected damage to the sensor element 46 is due to other effects on the sensor element 46, in particular a deformation of the bottom, and not to the gas escape. Then, a signal assigned to the deformation of the bottom can be emitted by the measuring device 48.

[0056] Figure 4 According to another embodiment of the present invention, a schematic diagram of a battery assembly 10 is shown in a cross section perpendicular to the x-direction. In this case, the battery assembly 10 can be constructed as described above. Only the gas discharge channel 22 is shown in more detail.

[0057] In addition, a housing cover 58 is shown here as a further component of the housing 18. The housing cover can also be designed as a cooling cover and comprise a cooling device 58' with integrated cooling channels through which a coolant can flow.

[0058] The housing bottom 20 can also be designed as a cooling bottom. In this example, the cooling bottom also has a cooling channel 20 'through which a cooling medium can flow, which cooling channel should be understood as a part of the cooling bottom 20. The gas escaping from the cell exhaust opening 26 of the cell 12 can enter through the inlet area 30 of the gas outlet channel 22. The inlet area 30 is designed as an opening in the channel wall 28 provided by the housing bottom 20. The underbody protection device 40 providing another channel wall 42 can be connected to the cooling bottom 20 through a gas deflection structure 60, for example, it is screwed to the bottom 20 through the gas deflection structure 60, especially in the area between two cell stacks 14 where a cell module 62 can be provided. The gas deflection structure 60 can form a longitudinal channel 64, which extends along and opposite to the x-direction and is respectively bounded by a channel inner wall 66 on both sides, in which openings 68 are provided, and the gas 24 can be guided into the channel interior 64 or guided through the gas deflection structure 60 through such a channel inner wall 66 of the gas deflection structure 60. The openings 68 can have different sizes along and opposite to the x-direction of the respective gas deflection structure 60 and, in particular, can also have different positions in the gas discharge channel 22 depending on the gas deflection structure 60. This allows targeted gas distribution and gas deflection along one or more flow paths 34 in the gas discharge channel 22, which can be achieved, for example, in Figure 5 Shown in.

[0059] Figure 5 Here again, a schematic diagram of the gas discharge channel 22 as part of the battery assembly 10, in particular of its interior 32, is shown, wherein the battery housing 18 accommodating the battery cells 12 and the sensor device 44 is not shown here. Here, for example, the underbody protection device 40 as part of the gas discharge channel 22 can be seen, and an outlet area 36 for discharging the gas 24 escaping from the battery cells 12 and introduced into the gas discharge channel 22 via the corresponding inlet area 30 via a suitable gas discharge path 34, in particular into the surrounding environment 38. The gas 24 guided in the gas discharge channel 22 and the corresponding gas discharge path 34, along which the gas 24 flows, are shown here by the same arrows. By Figure 5 The above-mentioned gas deflection structure 60, which is not explicitly shown in FIG. 1 , results in three main flow paths 64 ′, which essentially correspond to the flow paths in FIG. Figure 464 of the gas deflection structure 60 described in FIG. The gas deflection structure 60 is designed, for example, so that its inner wall 66 has no opening 68 or has a significantly smaller opening 68 in the area of ​​the outlet opening 36. Therefore, the gas 64 entering the gas outlet channel 22 via the inlet area 30 in the area of ​​the outlet opening 36 is first forced to flow in the x-direction, because the gas cannot pass through the gas deflection structure 60 in the area close to the outlet. In the front area of ​​the gas deflection structure 60, in which the opening 68 or the opening 68 with an enlarged shape is present, a lateral flow of the gas 24 can be achieved, in this example, in the opposite direction to the y-direction shown, whereby the gas can be distributed to different gas deflection structures 60, in particular to the interiors 64 of different gas deflection structures 60, and can reach the outlet 36 along three main flow paths 64'. By means of this gas distribution, cooling of the gas 24 and particle separation can be achieved simultaneously.

[0060] In order to be able to detect the gas escape as effectively as possible, one or more of the aforementioned sensor elements 46 can be arranged, for example, in such a gas deflection structure 60 and thus in the region within the main flow path 64 ′, as exemplarily in Figure 4 . For example, exactly one such sensor element 46 can be provided in the respective main flow path 64'. The evaluation of the sensor element 46 can be performed by a common measuring device 48. Overall, therefore, reliable gas escape detection can be achieved even with very few sensor elements 46. Thus, faults can be identified using particularly technically simple components and, in addition to other detection possibilities, advantageous additional fault confirmation concepts can be generated, for example. Such other detection possibilities include the use of other sensors, such as temperature sensors and / or pressure sensors.

[0061] Overall, these examples show how the invention can provide a sensor system for the heat dissipation of a cell, in particular as an alternative to a pressure sensor in the area of ​​an underbody protection.

Claims

1. A battery assembly (10) having a sensor device (44) for detecting gas emission from at least one battery cell (12) of the battery assembly (10), wherein: The battery assembly (10) comprises: - at least one battery cell (12), the at least one battery cell having a releasable battery cell vent opening (26), - a gas outlet channel (22), the gas outlet channel having at least one gas inlet region (30) capable of introducing gas (24) escaping from the battery cell exhaust opening (26) into the gas outlet channel (22), at least one gas outlet region (36) and at least one flow path (34) from the at least one gas inlet region (30) to the at least one gas outlet region (36), It is characterized in that the sensor device (44) comprises at least one sensor element (46) which is arranged in the gas discharge channel (22) and projects into the flow path (34), the at least one sensor element having an electrical line (49) to which a test voltage (U) can be applied, wherein the sensor element (46) is designed such that the electrical line (49) can be damaged by gas (24) escaping from at least one battery cell (12) and flowing through the gas discharge channel (22) along at least one flow path (34), and - wherein the sensor device (44) is designed to detect damage to a line (49) to which a test voltage (U) is applied based on measured electrical variables (I, R) assigned to the line (49), and to detect gas escape based on the detected damage to the line (49).

2. The battery assembly (10) according to claim 1, It is characterized in that The sensor element (46) has a predetermined breaking point (54), wherein the conductor (49) can be damaged by damage or breaking of the sensor element (46) at the predetermined breaking point (54).

3. A battery assembly (10) according to any one of the preceding claims, It is characterized in that The sensor element (46) is designed in such a way that the sensor element (46) can be damaged at a predetermined breaking point (54) by a pressure effect (p) on the sensor element (46) which is or can be generated by gas (24) escaping from at least one battery cell (12) and flowing along a flow path (34).

4. A battery assembly (10) according to any one of the preceding claims, It is characterized in that The sensor element (46) comprises a carrier (50), in particular comprising plastic, on which an electrical conductor (49) is arranged and / or in which the electrical conductor (49) is embedded, wherein the sensor element (46) is arranged such that the carrier (50) together with the electrical conductor (49) protrudes into the flow path (34), in particular wherein the predetermined breaking point (54) is designed as at least a part of the carrier (50).

5. The battery assembly (10) according to any one of the preceding claims, It is characterized in that The carrier (50) is designed as a small thin plate (56) or includes a small thin plate (56). - the small plate has a length (L) and a width (B), - the small thin plate extends into the flow path (34) along the direction of its length (L), - the width (B) of the small plate is greater than the conductor width of the electrical conductor (49) in a direction perpendicular to the length (L) of the small plate (56), and The surface of the small plate is arranged at an angle different from zero, preferably at a right angle, to the flow direction of the gas (24) flowing along the flow path (34).

6. A battery assembly (10) according to any one of the preceding claims, It is characterized in that The carrier (50) has a first end (50a) and a second end (50b) opposite in a first direction (z), wherein the carrier (50) is arranged on a wall (28, 42) of a gas outlet channel (22) only with the first end (50a), and in particular, the predetermined breaking point (54) is arranged closer to the first end (20a) than the second end (20b).

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), each of which has a releasable battery cell exhaust opening (26), wherein a gas outlet channel (22) is connected to the battery cell exhaust opening (26) in such a way that gas (24) escaping from each battery cell exhaust opening (26) can be introduced into the gas outlet channel (22) via at least one gas inlet region (30).

8. A battery assembly (10) according to any one of the preceding claims, It is characterized in that The battery assembly (10) comprises a housing (18) in which at least one battery cell (12) is arranged. wherein the housing (18) comprises a housing wall (20), in particular a housing bottom (20), wherein the battery assembly (10) has a plate (40), in particular an underbody protection device (40), which is located outside the housing (18) and opposite the housing wall (20), wherein the housing wall (20) and the plate (40) form walls (28, 42) of the gas discharge channel (22), the flow path (34) extending through the intermediate space (32) between the housing wall (20) and the plate (40), and - wherein the sensor element (46) projects into the intermediate space (32).

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

10. A method for detecting gas evolution of at least one battery cell (12) of a battery assembly (10), wherein: Gas (24) escaping from a cell exhaust opening (26) of at least one cell (12): - introduced into a gas discharge channel (22) of the battery component (10) via at least one gas inlet region (30) of the gas discharge channel (22), - being guided along at least one flow path (34) from at least one gas inlet region (30) via the gas outlet channel (22) to at least one gas outlet region (36) of the gas outlet channel (22), and - is discharged from the gas discharge channel (22) via at least one gas outlet region (36), It is characterized in that the sensor device (44) comprises at least one sensor element (46) which is arranged in the gas discharge channel (22) and projects into the flow path (34), the at least one sensor element comprising an electrical line (49) to which a test voltage (U) is applied, wherein the electrical conductor (49) can be damaged by a gas (24) flowing through the gas discharge channel (22) along at least one flow path (34), and - wherein the sensor device (44) detects damage to the line (49) to which the test voltage (U) is applied based on the measured electrical variables (I, R) assigned to the line (49) and detects gas escape based on the detected damage to the line (49).

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