Battery single cell with a disconnecting device, battery system, and motor vehicle

Abstract

The invention relates to a battery cell (1) for a battery system (2) of a motor vehicle (3), having a flexible cell wall (4), a cell interior space (5) formed by the cell wall (4), an active material (6) arranged in the cell interior space (5) for storing and releasing electrical energy, and a discharge device (7) for providing an electrical coupling of the active material (6) to other components of the battery system (2), wherein the discharge device (7) has a first discharge section (7a) and a second discharge section (7b), and the second discharge section is mechanically and electrically coupled to the first discharge section (7a). The battery cell (1) has a disconnecting device (8) for disconnecting the mechanical and electrical couplings and an actuator device (9) for moving the disconnecting device (8) in accordance with a pressure difference between the interior pressure and the exterior pressure of the cell. Furthermore, the invention relates to a battery system (2) and a motor vehicle (3).

Description

Field of the Invention

[0001] The present invention relates to a battery cell of a battery system for a motor vehicle. Furthermore, the present invention relates to a battery system for a motor vehicle having a battery cell of the type according to the invention and to a motor vehicle having a battery system of the type according to the invention. Background Art

[0002] Cylindrical and prismatic battery cells are known which have safety devices, such as a Current Interrupt Device (CID) or an Overcharging Safety Device (OSD), in order to protect the battery cell, in particular against thermal runaway. Such safety devices usually have a safety circuit which interrupts the electrical coupling between, for example, the active material integrated as a cell winding and the electrodes led out of the battery cell in the case of a critical internal pressure, a critical internal temperature or a critical gas concentration inside the cell. Such safety devices can currently only be implemented very cost-intensively for battery cells designed as pouch cells.

[0003] A battery cell designed as a pouch cell is known from DE 10 2016 110 778 A1, which has a protection device, in which the electrical coupling between a first internal conductor and a second internal conductor of the battery cell can be disconnected depending on the swelling of the battery cell. For this purpose, the second internal conductor is held, for example, on the lower cell wall by an adhesive layer and is electrically coupled to a first section of the first internal conductor by a bending section. The first section is held, for example, on the upper cell wall of the battery cell by an adhesive layer and is electrically coupled to a second section of the first internal conductor by a rated breaking point. The second section is coupled to the second internal conductor by an electrically insulating adhesive layer. In the case of critical swelling of the battery cell, the upper cell wall is removed from the lower cell wall in such a way that the bending section is at least partially plastically deformed and the rated breaking point breaks. As a result, the electrical coupling between the first section and the second section of the first internal conductor is interrupted. In this way, the battery cell can be automatically disconnected from the rest of the battery system. The bending area is designed to remain unchanged when the battery cell returns, for example, from a plastic deformation, so that the interruption of the electrical coupling between the first section and the second section of the first internal conductor is further maintained.

[0004] Known battery cells with a protective device designed as a pouch-type single cell have the disadvantage that a relatively large deformation of the cell wall is required to interrupt the electrical coupling. This is particularly problematic in battery systems with a pressing device by means of which the battery cells can be pressed together in order to increase the effective power and the service life. Another disadvantage is that an arc can form when the current load is high and the electrical coupling is interrupted too slowly, and the current first flows through the arc. Heat is thereby generated, by means of which previously disconnected discharge elements can be welded. The elements are thereby electrically coupled to each other again. Summary of the Invention

[0005] Accordingly, the technical problem to be solved by the present invention is to eliminate or at least partially eliminate the above-mentioned disadvantages in the battery cell. The technical problem to be solved by the present invention lies in particular in providing a battery cell, a battery system and a motor vehicle which ensure in a simple and cost-effective manner a better disconnection of the electrical coupling of a damaged battery cell from the other battery cells of the battery system.

[0006] This technical problem is solved according to the invention by a battery cell for a battery system of a motor vehicle, by a battery system for a motor vehicle and by a motor vehicle.

[0007] Other features and details of the present invention result from the description and the drawings. Here, the features and details described in connection with the battery cell according to the invention of course also apply in connection with the battery system according to the invention and the motor vehicle according to the invention and vice versa accordingly, so that the disclosure of the individual inventive aspects can always be alternately cited with respect to each other.

[0008] According to a first aspect of the invention, the technical problem is solved by a battery cell for a battery system of a motor vehicle. The battery cell has a flexible cell wall, a cell interior space formed by the cell wall, an active material arranged in the cell interior space for storing and releasing electrical energy, and a discharge device (Ableitervorrichtung) for providing an electrical coupling of the active material with other components of the battery system. The discharge device has a first discharge section and a second discharge section, the second discharge section being mechanically and electrically coupled to the first discharge section. According to the invention, the battery cell has a disconnecting device (Trennvorrichtung) for disconnecting the mechanical and electrical coupling between the first discharge section and the second discharge section and an actuator device for moving the disconnecting device, wherein the actuator device is designed to move the disconnecting device from an original position into an interrupt position between the first discharge section and the second discharge section in the case of a positive pressure difference between the internal pressure in the cell interior space and a smaller external pressure outside the cell interior space.

[0009] The battery system is preferably designed to operate the electric motor and the power electronics of a motor vehicle. The battery cell is preferably designed as a pouch cell. The cell wall is formed by a flexible material, such as aluminum or plastic, etc. The cell wall is preferably designed as a film. In addition, the cell wall has at least one seam for forming an outwardly sealed interior space of the cell. The seam is preferably designed as a weld seam or an adhesive seam, etc.

[0010] The active material is arranged in the interior space of the cell. Within the scope of the present invention, the active material is understood to be a material or a mixture of materials that ensures the storage and release of electrical energy through the discharger of the battery cell. The active material preferably has lithium ions. According to the present invention, the active material can be arranged in the interior space of the cell in the form of layers, especially stacked or folded.

[0011] The discharger device is designed to provide an electrical coupling between the active material and other components of the battery system, and the other components are, for example, other battery cells especially within the scope of a series circuit or a parallel circuit, or the main discharger of the battery system for outputting electrical energy to the electrical load of the motor vehicle and for introducing electrical energy to charge the battery cell. To provide the electrical coupling, the discharger device has a first discharger section and a second discharger section.

[0012] The first discharger section is mechanically and electrically coupled to the second discharger section. The mechanical and electrical coupling between the first discharger section and the second discharger section can be formed, for example, by adhesion, hemming, pressing, fusion welding or brazing, etc. Preferably herein, the first discharger section and the second discharger section form a common overlapping area. The overlapping area preferably has a break gap facing the disconnecting device. The break gap preferably has an enlargement to better introduce the disconnecting device into the break gap. Alternatively, according to the present invention, it can be provided that a part of the disconnecting device is already arranged inside the break gap. During pressing, the first discharger section and the second discharger section are pressed against each other in the overlapping area by a pressing force. The pressing force can be provided, for example, by the internal stress of the first discharger section and / or the second discharger section or by an additional pressing device, such as a spring device.

[0013] According to an alternative embodiment, the first discharger section and the second discharger section can be designed integrally or monolithically with each other. In this case, it is preferred that the intermediate area between the first discharger section and the second discharger section is arranged transversely to, particularly preferably perpendicular to, the disconnecting device, thus ensuring a reliable cut of the intermediate area by the disconnecting device. The transition area between the first discharger section and the second discharger section preferably has a rated fracture site or a crease, etc.

[0014] The disconnecting device is designed to mechanically and electrically couple a first discharge section to a second discharge section in the original position and to interrupt the mechanical and electrical coupling in the interrupt position. In the interrupt position, the disconnecting device is preferably arranged between the first discharge section and the second discharge section, so that the first discharge section and the second discharge section are arranged at a distance from each other. The disconnecting device is preferably designed to open, in the interrupt position, a single cell wall, for example at a seam, so that the single cell gas can escape from the single cell interior. Further preferably, the disconnecting device has end stops which are designed to limit the movement of the disconnecting device, for example in the interrupt position or in the direction of movement from the original position towards the interrupt position, in order to avoid, for example, the disconnecting device falling out of the battery cell.

[0015] The actuator device is designed to move the disconnecting device from the original position into the interrupt position as a function of the ratio of the internal pressure of the single cell to the external pressure of the single cell. In a fully functional battery cell, the disconnecting device is preferably arranged in the original position. The actuator device is also designed to generate the movement by the action of a positive pressure difference between the internal pressure of the single cell and the external pressure of the single cell. In the context of the present invention, a positive pressure difference between the internal pressure of the single cell and the external pressure of the single cell is understood to mean that the internal pressure of the single cell is greater than the external pressure of the single cell. The increase in the internal pressure of the single cell is generally due to a chemical reaction of the active material, in particular due to ageing or overload. The actuator device is thus mechanically coupled to the internal pressure of the single cell such that the pressure difference acts on the actuator device.

[0016] The actuator device is preferably designed to move the disconnecting device into the interrupt position only when the positive pressure difference exceeds a pressure threshold. Here, two alternative embodiments are preferred according to the invention. According to the first embodiment, the actuator device is designed to move the disconnecting device out of the original position only when the pressure threshold is reached. The movement of the disconnecting device into the interrupt position is then effected in a relatively fast continuous movement. According to the second embodiment, the actuator device is designed to move the disconnecting device in the direction of the interrupt position by a correspondingly small partial section already when a relatively low positive pressure difference occurs. The interrupt position is only reached when the pressure threshold is reached. The movement of the disconnecting device into the interrupt position is then effected in a relatively slow, possibly discontinuous movement.

[0017] The pressure threshold is preferably determined based on the mechanical and chemical or electrochemical characteristic values of the single battery cell, and it is determined at which pressure difference the electrical coupling between the single battery cell and the rest of the battery system should be disconnected in order to avoid or at least reduce further damage to the single battery cell and the battery system. The pressure threshold is preferably lower than the critical pressure threshold at which the seam of the single cell wall is at risk of opening. In this way, it can be prevented that the single cell gas escapes through the damaged seam and thus does not reach or reaches the pressure threshold with a large delay in the internal space of the single cell, for example in the case where the single battery cell has experienced thermal runaway.

[0018] The single battery cell preferably has a signal device which is designed to output a signal when the disconnecting device is in the interrupted position. The signal device is preferably designed to output a signal when the disconnecting device has been moved out of the original position, preferably when the disconnecting device has moved past approximately 50% of the section between the original position and the interrupted position. The signal device preferably has a fixed first electrical contact and a second electrical contact which can move together with the disconnecting device. In the original position, the first electrical contact and the second electrical contact are preferably separated from each other. In the interrupted position, the first electrical contact contacts the second electrical contact, so that the circuit is closed. In this way, the electrical decoupling of a specific single battery cell of the battery system can be detected reliably, simply and inexpensively.

[0019] The advantage of the single battery cell according to the invention compared to conventional single battery cells is that if the ratio of the internal pressure of the single cell to the external pressure of the single cell exceeds a critical limit value, the electrical coupling between the first discharge section and the second discharge section can be automatically interrupted in a simple device and in an inexpensive way. Due to the effective coupling of the actuator device with the pressure difference between the internal pressure of the single cell and the external pressure of the single cell, the measurement of the internal pressure of the single cell and the control device for controlling the actuator device are unnecessary. Therefore, compared to conventional single battery cells, the complexity of the single battery cell system is significantly reduced and the operating safety of the single battery cell is significantly improved.

[0020] According to a preferred extended design of the present invention, it can be provided in the battery cell that the disconnecting device has a wedge-shaped cross-section, wherein the pointed wedge-shaped end of the disconnecting device is oriented towards the disconnecting gap between the first discharge section and the second discharge section. The tip is preferably oriented such that when the disconnecting device moves linearly from the original position to the interrupt position, the tip moves between the first discharge section and the second discharge section to interrupt the mechanical and electrical coupling. By moving the disconnecting device into the disconnecting gap, the first wedge-shaped surface of the disconnecting device contacts the first discharge section, and the second wedge-shaped surface of the disconnecting device contacts the second discharge section. By further moving the disconnecting device in the direction of the interrupt position, a force can be applied to the first discharge section and the second discharge section by the disconnecting device in this way, and by this force, the first discharge section and the second discharge section can be pushed away from each other. When the interrupt position is reached, the first discharge section and the second discharge section are mechanically and electrically decoupled from each other and are spaced apart from each other by the disconnecting device. This has the advantage that a simple device can be used and the mechanical and electrical coupling between the first discharge section and the second discharge section can be reliably interrupted in a cost-effective manner.

[0021] According to a preference of the present invention, the disconnecting device has a cutting device (Schneidvorrichtung) for cutting the mechanical connection between the first discharge section and the second discharge section. The cutting device is preferably arranged on the disconnecting device such that the cutting device contacts and cuts the rated disconnecting line between the first discharge section and the second discharge section when moving from the original position to the interrupt position. The cutting device preferably has a cutting blade, which is preferably designed to be inclined with respect to the movement direction of the disconnecting device in order to reduce the maximum cutting force and thus the pressing force required to move the disconnecting device in the direction of the interrupt position. This has the advantage that the disconnection between the first discharge section and the second discharge section is improved by a simple device and in a cost-effective manner.

[0022] More preferably, the cutting device has a harder material than the region of the disconnecting device adjacent to the cutting device. The cutting device preferably has a metal or a hard ceramic, etc. Furthermore preferably, the cutting device has a smaller thickness than the adjacent region in order to better penetrate into the material of the discharge device. The cutting device is preferably arranged on the substrate of the disconnecting device by means of coating, shaping or bonding, etc. In the case of a cutting device made of a conductive material, the disconnecting device is preferably designed to move the cutting device far enough away from the first discharge section and / or the second discharge section into the interrupt position to avoid current flow or arcing, etc. between the first discharge section and the second discharge section through the cutting device. This has the advantage that the disconnection between the first discharge section and the second discharge section is improved by a simple device and in a cost-effective manner.

[0023] In a particularly preferred embodiment of the present invention, it can be provided in a battery cell that the disconnecting device is linearly guided by a linear guide so as to move between a first discharge section and a second discharge section. The linear guide preferably has a track, and the disconnecting device preferably abuts against the track and / or the track is at least partially surrounded by the disconnecting device. As an alternative or addition, the linear guide has a hollow body extending in the guiding direction of the linear guide, such as a hollow cylinder, a hollow right parallelepiped, a semi-circular channel, etc., and the disconnecting device is arranged in the hollow body and linearly guided. This has the advantage that the tilting (Verkanten) of the disconnecting device when moving into the interrupt position can be ensured in a simple device and in a cost-effective manner, and thus the safe movement of the disconnecting device into the interrupt position can be ensured. In this way, the prescribed disconnection between the first discharge section and the second discharge section is ensured.

[0024] Preferably, the disconnecting device is formed of an electrically insulating material or has an electrically insulating material. The electrically insulating material is preferably arranged on the substrate of the disconnecting device by means of coating, molding or bonding, etc. The disconnecting device is preferably designed such that the insulating material is arranged in the interrupt position between the first discharge section and the second discharge section, thereby reliably avoiding electrical coupling between the first discharge section and the second discharge section. This preferably also includes self-generated electrical coupling that may be caused by impacts or vibrations, etc. Therefore, the disconnecting device is preferably designed such that the insulating material contacts the first discharge section and the second discharge section in the interrupt position and keeps them at a distance from each other. This has the advantage that safe electrical isolation (or electrical disconnection) between the battery cell and other components of the battery system can be achieved by a simple device and in a cost-effective manner.

[0025] According to a preferred embodiment of the present invention, the actuator device has a pulling-back (Rückzieh) device for providing a reaction force relative to the pressure difference related to the pressure difference and / or a holding (Rückhalte) device for providing a holding force for holding the disconnecting device. The pulling-back device preferably includes a spring device.

[0026] The pulling-back device is preferably slack in the original position and can be tensioned by the movement of the disconnecting device in the direction of the interruption position, so that a restoring force in the direction of the original position can thereby be generated. The pulling-back device preferably has a defined characteristic curve adapted to the path-force level, in particular a spring characteristic curve. The pre-tensioning force or starting restoring force in the original position is preferably designed to be adaptable (or adjustable). Preferably, the pulling-back device is dimensioned such that the disconnecting device only reaches the interruption position when a preset pressure threshold is reached. The retaining device preferably has a friction surface and / or shear bolts and / or a rated breaking point and / or an adhesion layer and / or an adhesive layer, etc. The retaining device is preferably designed to provide a static retaining force. The retaining device is preferably designed to hold the disconnecting device in the original position when the pressure difference is below the pressure threshold and to release the disconnecting device when the pressure threshold is reached, for example due to the failure of the shear bolts, the rated breaking point or the adhesive layer. Alternatively, the retaining device according to the invention can be designed to prevent the movement of the disconnecting device such that the interruption position is avoided when the internal pressure of the single cell is below the pressure threshold. This has the advantage that the required disconnection of the electrical coupling can be ensured in a simple and cost-effective manner.

[0027] The actuator device particularly preferably has a locking device for locking the pulling-back movement of the disconnecting device in the direction of the original position. The locking device preferably has a latching device, a locking pawl or locking teeth, etc. The locking device is preferably designed to restrict the movement direction of the disconnecting device such that only movement of the disconnecting device in the direction of the interruption position is allowed. Thereby, oscillations of the disconnecting device, in particular translational oscillations, caused, for example, by excitation oscillations or impacts, etc., can be avoided. As a supplement or alternative, the locking device is designed to hold the disconnecting device in the interruption position. It is thus possible to avoid that, after the electrical coupling between the first discharge section and the second discharge section is disconnected, the disconnecting device leaves the interruption position and the electrical coupling is restored. This has the advantage that the operating safety of the battery single cell is improved in a simple and cost-effective manner.

[0028] According to a second aspect of the present invention, the technical problem is solved by a battery system for a motor vehicle. The battery system has a system housing. According to the invention, a plurality of battery cells according to the invention are arranged within the system housing. The system housing is preferably formed from a relatively hard (or relatively rigid) material in order to provide protection for the battery cells against external mechanical influences, for example due to a collision of the motor vehicle. The battery cells are preferably electrically connected to one another, for example in series and / or in parallel. The battery cells are preferably combined into one or more battery cell stacks. In addition, the battery system preferably has a pressurizing device for one or more, preferably all, battery cell stacks for pressing the battery cells of the respective battery cell stack together. The battery system preferably has two or more main dischargers for electrically coupling the battery system to the motor vehicle. The battery system is preferably designed to operate an electric motor and power electronics of the motor vehicle.

[0029] All of the advantages already described for the battery cells according to the first aspect of the invention are achieved in the battery system according to the invention. Thus, the battery system according to the invention has the following advantages over conventional battery systems, namely that if the ratio of the internal pressure of the cell to the external pressure of the cell exceeds a critical limit value, the electrical coupling between the first discharger section and the second discharger section can be automatically interrupted in a simple and cost-effective manner. Due to the effective coupling of the actuator device to the pressure difference between the internal pressure of the cell and the external pressure of the cell, measurement of the internal pressure of the cell and a control device for controlling the actuator device are unnecessary. Thus, compared to conventional battery cell systems, the complexity of the battery cell system is significantly reduced and the operating safety of the battery cell system is significantly improved.

[0030] According to a third aspect of the present invention, the technical problem is solved by a motor vehicle. The motor vehicle has an electric drive system having an electric motor for driving the motor vehicle. According to the invention, the drive system has a battery system according to the invention in order to supply electrical energy to the electric motor. The battery system and the electric motor are preferably electrically coupled via power electronics for operating the electric motor. According to the invention, the motor vehicle can have a plurality of electric motors for driving the motor vehicle, in particular an electric motor for driving the front axle of the motor vehicle and an electric motor for driving the rear axle of the motor vehicle.

[0031] All of the advantages already described for the battery single cell according to the first aspect of the invention and for the battery system according to the second aspect of the invention are produced in a motor vehicle according to the invention. Thus, a motor vehicle according to the invention has the following advantages over conventional motor vehicles, namely that if the ratio of the internal pressure of the single cell to the external pressure of the single cell exceeds a critical limit value, the electrical coupling between the first discharge section and the second discharge section can be automatically interrupted in a simple and cost-effective manner by means of a simple device. Due to the effective coupling of the actuator device to the pressure difference between the internal pressure of the single cell and the external pressure of the single cell, it is unnecessary to measure the internal pressure of the single cell and a control device for controlling the actuator device. Therefore, compared with conventional motor vehicles, the complexity of the motor vehicle is significantly reduced and the running safety of the motor vehicle is significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] The battery single cell according to the invention, the battery system according to the invention and the motor vehicle according to the invention are explained in more detail below with reference to the drawings. In the drawings, schematically:

[0033] Figure 1 A perspective view of a battery single cell according to a first preferred embodiment of the invention in its original position is shown;

[0034] Figure 2 Is shown in cross-section Figure 1 A partial view of the battery single cell in its original position in

[0035] Figure 3 Is shown in cross-section Figure 1 A partial view of the battery single cell in its interrupted position in

[0036] Figure 4 A partial view of a battery single cell according to a second preferred embodiment of the invention in its original position is shown in cross-section;

[0037] Figure 5 A partial view of a battery single cell according to a third preferred embodiment is shown in perspective;

[0038] Figure 6 A battery system according to a preferred embodiment of the invention is shown in cross-section; and

[0039] Figure 7 A preferred embodiment of a motor vehicle according to the invention is shown in a side view.

[0040] Elements having the same function and mode of operation are provided with the same reference numerals in Figures 1 to 7 herein. DETAILED DESCRIPTION

[0041] In Figure 1FIG. schematically shows in perspective a battery cell 1 in the original position A according to a first preferred embodiment of the present invention. The battery cell 1 is designed as a pouch cell and has a flexible cell wall 4 which has a surrounding seam 23 in the edge region and encloses a cell interior space 5. A discharge device 7 leads out from the cell interior space 5 on one side of the battery cell 1. The discharge device 7 has a first discharge section 7a protruding into the cell interior space 5 and a second discharge section 7b arranged outside the cell interior space 5, and the second discharge section is mechanically and electrically coupled to the first discharge section 7a via an overlapping region with a break gap 11 formed. In addition, a disconnecting device 8 for mechanically and electrically disconnecting the first discharge section 7a from the second discharge section 7b protrudes from the cell interior space 5. The disconnecting device 8 is shown in the original position A and can be moved to an interruption position U (see Figure 3 ) by means of an actuator device 9 using the pressure difference between the cell interior pressure in the cell interior space 5 and the lower cell exterior pressure outside the cell interior space 5. In the original position A, the disconnecting device is arranged at a distance from the overlapping region and faces the break gap 11.

[0042] Figure 2 FIG. schematically shows in a sectional view a partial view of the battery cell 1 in the original position A Figure 1 . In this view, a stack composed of active material 6 arranged in the cell interior space 5 is shown, and the stack is electrically coupled to the first discharge section 7a. The disconnecting device 8 is linearly guided along the first discharge section 7a by a linear guide 13 and has a cutting device 12 with a wedge-shaped design. The wedge-shaped end 10 of the cutting device 12 is arranged adjacent to the break gap 11 and faces the break gap 11. The disconnecting device 8 is held in the original position A on the first discharge section 7a by a holding device 15 designed as an adhesive part. The cell wall 4 is preferably sealed relative to the disconnecting device 8 by a sealing device (not shown) to prevent cell gas from escaping from the cell interior space 5. The actuator device 9 is designed to move the disconnecting device 8 from the original position A to the interruption position U by using the cell interior pressure to overcome the holding device 15 when the pressure difference between the cell interior pressure and the cell exterior pressure exceeds a pressure threshold.

[0043] Figure 3 FIG. schematically shows in a sectional view a partial view of the battery cell 1 in the interruption position U Figure 1 . In the interruption position U, the wedge-shaped end 10 of the disconnecting device 8 moves between the first discharge section 7a and the second discharge section 7b of the discharge device 7, so that the mechanical and electrical coupling between the first discharge section 7a and the second discharge section 7b is interrupted. Thus, the battery cell 1 is electrically decoupled from the battery system 2 (see Figure 5 ).

[0044] Figure 4 A partial view of the battery cell 1 according to the second preferred embodiment of the present invention in the original position A is schematically shown in a sectional view. In this second embodiment, the actuator device 9 has a retraction device 14 designed as a helical spring. The movement of the disconnecting device 8 in the direction of the disconnecting gap 11 can be affected by the retraction device 14 such that the disconnecting device is arranged in the interruption position U only when a pressure threshold is reached. An end stop 24 is arranged on the linear guide 13 to positively prevent the disconnecting device 8 from moving out beyond the interruption position U. In this embodiment, the linear guide 13 is also designed as a sensor system for detecting the interruption position U.

[0045] In Figure 5 A partial view of the battery cell 1 according to the third preferred embodiment is schematically shown in a perspective view. The linear guide 13 is designed as a hollow cylinder, wherein the disconnecting device 8 has a cylindrical section 8a linearly guided in the hollow cylinder. A locking device 16 (hidden in this view) is arranged within the linear guide 13 to prevent the disconnecting device 8 from being retracted in the direction of the original position A. The discharging device 7 is not shown in this view.

[0046] Figure 6 A battery system 2 according to a preferred embodiment of the present invention is schematically shown in a sectional view. The battery system 2 has a plurality of battery cells 1 according to the present invention, which are combined into a plurality of cell stacks 20 and arranged within a system housing 17 of the battery system 2. The cell stacks 20 are each supported in the system housing 17 by a pressurizing device 21.

[0047] In Figure 7 A preferred embodiment of a motor vehicle 3 according to the present invention is schematically shown in a side view. The motor vehicle 3 has an electric drive system 18, which has an electric motor 19 for driving the motor vehicle 3, power electronics 22 for controlling the power of the electric motor 19, and a battery system 2 according to the present invention, which is used to provide electrical energy for operating the power electronics 22 and the electric motor 19.

[0048] List of reference numerals

[0049] 1 Battery cell

[0050] 2 Battery system

[0051] 3 Motor vehicle

[0052] 4 Cell wall

[0053] 5 Cell interior space

[0054] 6 Active material

[0055] 7 Discharge device

[0056] 7a First discharge section

[0057] 7b Second discharge section

[0058] 8 Disconnecting device

[0059] 8a Cylindrical section

[0060] 9 Actuator device

[0061] 10 Wedge-shaped end

[0062] 11 Disconnecting gap

[0063] 12 Cutting device

[0064] 13 Linear guide

[0065] 14 Pull-back device

[0066] 15 Holding device

[0067] 16 Locking device

[0068] 17 System housing

[0069] 18 Drive system

[0070] 19 Electric motor

[0071] 20 Single-cell stack

[0072] 21 Pressurizing device

[0073] 22 Power electronics

[0074] 23 Seam

[0075] 24 End stop

[0076] A Original position

[0077] U Interrupt position

Claims

1. A battery cell (1) for a battery system (2) of a motor vehicle (3), having a flexible cell wall (4), a cell interior space (5) formed by the cell wall (4), an active material (6) arranged in the cell interior space (5) for storing and releasing electrical energy, and a discharging device (7) for providing an electrical coupling of the active material (6) to other components of the battery system (2), wherein, The discharge device (7) has a first discharge section (7a) and a second discharge section (7b), and the second discharge section is mechanically and electrically coupled to the first discharge section (7a). It is characterized in that The battery cell (1) has a disconnecting device (8) for disconnecting the mechanical and electrical coupling between the first discharge section (7a) and the second discharge section (7b), and an actuator device (9) for moving the disconnecting device (8), wherein the actuator device (9) is designed to move the disconnecting device (8) from the original position (A) to the interruption position (U) between the first discharge section (7a) and the second discharge section (7b) in the case of a positive pressure difference between the internal pressure in the cell internal space (5) and the smaller external pressure outside the cell internal space (5), wherein the actuator device (9) has a pulling-back device (14) for providing a reaction force relative to the pressure difference related to the pressure difference, and the pulling-back device (14) is configured to be slack in the original position (A) and can be tensioned by moving the disconnecting device (8) in the direction towards the interruption position (U), so that a restoring force in the direction towards the original position (A) can be achieved thereby, and the actuator device (9) has a locking device (16) for locking the pulling-back movement of the disconnecting device (8) in the direction towards the original position (A).

2. The battery cell (1) according to claim 1, It is characterized in that The disconnecting device (8) has a wedge-shaped cross-section, and the pointed wedge-shaped end (10) of the disconnecting device (8) is oriented in the direction of the disconnecting gap (11) between the first discharge section (7a) and the second discharge section (7b).

3. The battery cell (1) according to claim 1 or 2, It is characterized in that The disconnecting device (8) has a cutting device (12) for cutting the mechanical connection between the first discharge section (7a) and the second discharge section (7b).

4. The battery cell (1) according to claim 3, It is characterized in that The cutting device (12) has a material harder than the area of the disconnecting device (8) adjacent to the cutting device (12).

5. The battery cell (1) according to claim 1, It is characterized in that The disconnecting device (8) is linearly guided by a linear guide (13) so as to move between the first discharge section (7a) and the second discharge section (7b).

6. The battery cell (1) according to claim 1, It is characterized in that The disconnecting device (8) is formed of an electrically insulating material or has an electrically insulating material.

7. The battery cell (1) according to claim 1, It is characterized in that The actuator device (9) has a holding device (15) for providing a holding force for holding the disconnecting device (8).

8. A battery system (2) for a motor vehicle (3), having a system housing (17), It is characterized in that A plurality of battery cells (1) according to one of the preceding claims are arranged in the system housing (17).

9. A motor vehicle (3) having an electric drive system (18) with an electric motor (19) for driving the motor vehicle (3), characterized in that, the drive system (18) has a battery system (2) according to claim 8 for supplying electrical energy to the electric motor (19).

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