DE102021102550A1 - Electrical energy store for a motor vehicle and motor vehicle - Google Patents

Abstract

The invention relates to an electrical energy store (1) for storing electrical energy for a motor vehicle, having a plurality of storage cells (4a, b) arranged one after the other along a stacking direction (5) for storing electrical energy, comprising at least one a housing (8), a piston element (9) that can be moved relative to the housing (8) and at least one working chamber (10), which is in each case partially delimited by the piston element (9) and the housing (8), for receiving a fluid and having a cylinder device (7), by means of which a Stacking direction (5) at least indirectly acting on the storage cells (4a, b) force can be brought about.

Description

The invention relates to an electrical energy store for a motor vehicle according to the preamble of patent claim 1. The invention also relates to a motor vehicle with at least one such energy store.

Of the WO 2017/133856 A1 a battery module with several battery cells can be seen as known. The battery module has a plurality of partitions, with a battery cell being arranged between two partitions. Furthermore, a spring element, in particular a tension and/or compression spring element, is arranged between two partitions adjacent to a battery cell, which is arranged in contact with and/or connected to the two partitions in such a way that a value of a deformation constant of the spring element is one of the two Dividers transmitted to the battery cell force determined. Furthermore, the WO 2012/097980 A1 a battery having a plurality of battery cells forming a cell stack abutting a bottom plate of the battery. From the WO 2010/081704 A2 an electric energy storage device is known which has a plurality of storage cells in a flat shape. A plurality of storage cells are stacked in a stacking direction to form a cell block and are held together by a clamping device between two pressure plates.

The object of the present invention is to create an electrical energy storage device for a motor vehicle and a motor vehicle with such an electrical energy storage device, so that a particularly advantageous operation of the energy storage device can be implemented.

This object is achieved according to the invention by an electrical energy store having the features of patent claim 1 and by a motor vehicle having the features of patent claim 10 . Advantageous configurations of the invention are the subject matter of the dependent claims.

A first aspect of the invention relates to an electrical energy store, also referred to simply as an energy store, for storing electrical energy or electric current for a motor vehicle. This means that the motor vehicle, which is preferably designed as a motor vehicle, in particular as a passenger car, includes the electrical energy store in its fully manufactured state. The electrical energy storage device is, for example, a storage module, also referred to simply as a module, of a storage device designed to store electrical energy, which storage device comprises, for example, a plurality of storage modules in or by means of which the electrical energy is to be stored or stored. In this case, the memory modules can be electrically connected to one another. Furthermore, it is conceivable that the electrical energy store according to the first aspect of the invention is a or the previously mentioned storage device, which has a plurality of storage modules, in particular electrically connected to one another. The electrical energy store is preferably a high-voltage component whose electrical voltage, in particular electrical operating or nominal voltage, is greater than 50 volts, in particular greater than 60 volts, and preferably amounts to several hundred volts. As a result, for example, particularly high electrical power can be realized for, in particular, purely electrical driving of the motor vehicle. The motor vehicle is preferably a hybrid or electric vehicle, in particular a battery electric vehicle (BEV). It is preferably provided that the motor vehicle has at least one electrical machine in its completely manufactured state, by means of which the motor vehicle can be driven, in particular purely electrically. It is preferably provided that the electrical machine is a high-voltage component whose electrical voltage, in particular electrical operating or nominal voltage, is greater than 50 volts, in particular greater than 60 volts, in particular and preferably several hundred volts.

The electrical energy store has a plurality of storage cells, also referred to simply as cells, for storing the electrical energy. The memory cells follow one another along a stacking direction and are therefore arranged one behind the other. For example, the memory cells are electrically connected to one another. The storage cells are preferably individual cells, that is to say individual components which are formed separately from one another.

In order to be able to implement a particularly advantageous operation of the energy store, it is provided according to the invention that the electrical energy store has at least one cylinder device which has a housing and a piston element which can be moved relative to the housing, in particular along a direction of movement. For example, the piston element can be moved at least or exclusively translationally along the direction of movement relative to the housing, and is therefore displaceable. In addition, the cylinder device has at least one working chamber, which is in each case partially delimited by the piston element and the housing, in particular in each case directly. A fluid can be accommodated or accommodated in the working chamber, so that a force acting at least indirectly on the storage cells along the stacking direction can be brought about, in particular provided, by means of the cylinder device. with others In other words, the fluid that can be received or received in the working chamber can have a pressure or exert pressure on the housing and the piston element. This results in an actuating force acting at least indirectly, in particular directly, on the housing and on the piston element, in particular along the stacking direction or, for example, along an effective direction running parallel to the stacking direction. The aforementioned force, which can be generated, in particular made available, by the cylinder device or is generated, in particular made available, can result from the actuating force, or the actuating force is the aforementioned force, which can be made available or made available by the cylinder device becomes. The cylinder device can provide the force or the actuating force, for example, via the piston element and/or via the housing and thereby transmit it, for example along the stacking direction, at least indirectly, in particular directly, to the storage cells, thus exerting it. For example, it is provided that the direction of movement runs parallel to the direction of stacking, or the direction of movement coincides with the direction of stacking. In other words, the force can be applied to the memory cells along the stacking direction, as a result of which, for example, the memory cells can be compressed or pressed together along the stacking direction.

Since the working chamber is in each case partially delimited by the housing and by the piston element, volume changes in the working chamber result from relative movements taking place in particular along the direction of movement between the piston element and the housing. It is conceivable that when there is a reduction in the volume of the working chamber, the reduction in volume of which results, for example, from the fact that the piston element moves in a first direction, in particular parallel to the direction of movement or coinciding with the direction of movement, relative to the housing, at least part of the initially in the Working chamber recorded fluid from the working chamber can be discharged or is conveyed out, in particular is pushed out by means of the piston element. Alternatively or additionally, it is conceivable that when the volume of the working chamber increases, the volume of which increases, for example, because the piston element moves in a second direction that is opposite to the first direction and runs parallel to the direction of movement or coincides with the direction of movement, an initially part of the fluid that is arranged outside of the working chamber can be introduced into the working chamber or is introduced, in particular is sucked in. As a result, it is conceivable, for example, that the pressure of the fluid in the working chamber or the force provided by the cylinder device and acting at least indirectly on the storage cells remains at least essentially constant, so that in the invention the storage cells are acted upon by the at least almost constant force can. As a result, for example, the memory cells can also be securely held together or held against one another if, for example, there are changes in an outer dimension of the memory cells running in particular along the stacking direction. Such a change, also referred to as a change in size or volume, in the outer dimensions of the respective storage cell, running in particular along the stacking direction, can occur, for example, as a result of charging and discharging processes, i.e. when the storage cells are repeatedly charged and discharged alternately in succession. The charging of the respective storage cell is to be understood as meaning that the respective storage cell is supplied with electrical energy, which is stored in the respective storage cell. Charging does not necessarily mean that the storage cell is fully charged, ie is charged with maximum electrical energy. The discharging of the respective storage cell is to be understood as meaning that the storage cell provides the electrical energy stored in it, ie that the electrical energy stored in or by means of the respective storage cell is discharged from the respective storage cell. Discharging does not necessarily have to be understood to mean complete discharging of the storage cell. In particular, the respective storage cell is designed to store the electrical energy electrochemically.

The invention is based in particular on the following findings and considerations: During operation of the energy store and/or during charging and discharging processes, a very large change in volume of the storage cells can occur. The change in volume is to be understood as meaning that the aforementioned outer dimension of the respective memory cell, which runs along the stacking direction and is also referred to as the outer dimension, changes greatly, thus increasing and decreasing, so that between a first state in which the outer dimension is greatest respectively takes its largest value, and a second state in which the outer dimension is smallest or takes its smallest or lowest value, there is a very large difference. This leads to a very large change or fluctuation along the Stacking direction running, overall outer dimension of a cell stack, which is formed by the memory cells and in particular in that the memory cells are arranged along the stacking direction one after the other. Furthermore, it has been shown to be advantageous to hold the storage cells together in the stacking direction with an at least substantially constant pressure or an at least substantially constant force, i.e. to press or press against each other, in order to thereby, for example, secure and firm the cell stack to hold together. If, for example, the storage cells are now pressed together by means of a very rigid tie rod designed, for example, as a solid body, in particular in such a way that a tensile force acts in the tie rod and the tie rod exerts a compressive force on the storage cells, for example on both sides of the cell stack, by means of which the storage cells are held together or pressed together , there can be a large change or fluctuation in the compressive force as a result of the volume change described above. This can now be avoided by the invention. Since the piston element can be moved relative to the housing, in particular translationally, or vice versa, the cylinder device can allow changes in volume, i.e. changes or fluctuations in the described, external dimensions of the respective storage cell, without excessive changes or fluctuations in the force occurring or during the force acts at least substantially constantly on the storage cells.

For example, when the external dimensions increase, there is such a relative movement between the piston element and the housing that the volume of the working chamber decreases. In this way, for example, an excessive increase in force can be avoided. If, for example, the outer dimensions are reduced as a result, such a relative movement between the piston element and the housing can result that the volume of the working chamber increases. As a result, an undesired, excessive decrease in force can be avoided. This can be achieved in particular by the fact that when the volume of the working chamber decreases, at least part of the fluid initially held in the working chamber is discharged from the working chamber, and when the volume of the working chamber increases, at least part of the fluid initially arranged outside of the working chamber is introduced into the working chamber will or can flow in. It can thus be seen that the cylinder device can compensate for or allow fluctuations or changes in the external dimensions without an excessive fluctuation or change in the force occurring and in particular while the force acts at least essentially constantly on the storage cells. As a result, a desired, advantageous function of the energy store can be ensured even in the event of major changes in the volume of the storage cells. In particular, even in the event of major changes in the volume of the storage cell, the force can be exerted on the storage cells as an at least essentially constant, evenly distributed force, in particular a compressive force. The force acts on the storage cells along the stacking direction. In this case, the stacking direction is, for example, a spatial direction that can be defined by a structure, in particular by a cell structure, of the respective storage cell and/or of the cell stack. Investigations have shown that during charging and discharging along the spatial direction, i.e. along the stacking direction, there can be a volume change of 10 to 20 percent of the respective storage cell. However, during such a change in volume of the storage cells, the force acting on the storage cells or a pressure acting on the storage cells and resulting from the force, for example, should remain as constant as possible in order to be able to ensure the desired function of the energy storage device. Said pressure resulting from the force, which acts on the storage cells in particular along the stacking direction, is preferably at least essentially 10 bar. It was also found that the force acting on the storage cells or the pressure acting on the storage cells cannot be kept sufficiently constant by means of conventional, mechanical spring elements, ie spring elements designed as solid bodies, when the volume of the storage cells changes. It was also found that such conventional spring elements either allow an increase in volume, also referred to as elongation or extension, i.e. an increase in the external dimensions, also referred to as elongation, but this then leads to an excessive drop in force, or conventional spring elements lead in particular with an increase in the outer dimension, an excessively large pressure acts on the storage cells. A further finding on which the invention is based is that the change in volume, ie the change or fluctuation in the outer dimensions of the respective storage cell, takes place quasi-statically over the duration of an average charging process of the motor vehicle designed as an electric vehicle, for example.

The problems and disadvantages mentioned above can now be avoided by the invention the. Since the piston element and the housing can be moved relative to one another, in particular in a translatory manner, in particular along the direction of movement, the cylinder device allows changes in the volume of the storage cells, and therefore changes in the external dimensions, in particular along the stacking direction, without excessive changes in the force occurring. This means that the cylinder device can provide the force at least almost unchanged and thus constantly even with strong changes in volume, so that the force acts at least almost constantly on the storage cells, especially when there are changes in volume of the storage cells.

It is conceivable that an equalization chamber, which is provided in particular in addition to the working chamber and is arranged outside of the working chamber, is provided, which is formed or delimited, for example, by an equalizing tank. For example, the working chamber can be fluidically connected or connected to the equalizing chamber, so that at least part of the fluid initially contained in the working chamber can be discharged from the working chamber and introduced into the equalizing chamber when the volume of the working chamber decreases. If the volume of the working chamber increases or increases in volume, for example, at least part of the fluid initially held in the equalizing chamber can be discharged from the equalizing chamber and introduced into the working chamber, so that the force that can be made available or made available by the cylinder device and acts on the storage cells in particular along the stacking direction when there are changes in volume of the memory cells can be kept at least essentially constant. Furthermore, it is possible to compensate for changes in the volume of the fluid by means of the compensation chamber. If, for example, there is a thermally induced increase in volume of the fluid, in particular while there are no relative movements between the housing and the piston element, for example, at least part of the fluid initially contained in the working chamber can be discharged from the working chamber and introduced into the compensation chamber. If, for example, there is a thermally induced reduction in volume of the fluid, in particular if there are no relative movements between the piston element and the housing, at least part of the fluid initially held in the compensation chamber can be discharged from the compensation chamber and introduced into the working chamber. The cylinder device and, for example, the compensation chamber or the compensation container are parts of a system which is constructed similarly to a brake system of a motor vehicle and can therefore be used particularly advantageously for automotive applications, ie vehicle applications. In particular, a high level of robustness and advantageous temperature insensitivity of the system can be achieved. It is also possible, for example, to service and repair the system in workshops using known tools that are also used, for example, to service and repair brake systems.

Provision is preferably made for the piston element and/or the housing to be non-elastically deformable, ie non-rubber-elastically deformable, inherently rigid and thus dimensionally stable solids. Thus, the piston element is preferably not an elastically deformable membrane, but a solid body which is movable, in particular displaceable, in particular along the direction of movement relative to the housing.

In an advantageous embodiment of the invention, the piston element can be moved translationally along the stacking direction relative to the housing, and is therefore displaceable. In other words, it is preferably provided that the direction of movement runs parallel to the stacking direction or coincides with the stacking direction. As a result, the cylinder device can particularly advantageously allow volume changes running along the stacking direction, and therefore changes or fluctuations in the external dimensions, without excessive fluctuations or changes in the force occurring. With an increase in the external dimensions, for example, at least one part of the piston element that is initially arranged outside of the housing is moved into the housing, in particular pushed into it. If, for example, there is a decrease, that is, a reduction, in the outer dimensions, then, for example, at least the part of the piston element is moved out of the housing, in particular pushed out. As a result, changes in volume can be permitted in a particularly advantageous and simple manner.

In order to allow changes in the volume of the storage cell in a particularly advantageous manner while keeping the force at least essentially constant and being able to exert it particularly advantageously on the storage cells, it is provided in a further embodiment of the invention that the cylinder device follows the storage cells along the stacking direction. In other words, it is preferably provided that the storage cells and the cylinder device are arranged one behind the other along the stacking direction. As a result, the installation space requirement of the energy store can also be kept within a particularly small framework.

A further embodiment is characterized in that the cylinder device which follows the storage cells and thus the cell stack in the stacking direction is arranged on a first side of the cell stack which, via its first side, is subjected to the force provided by the cylinder device and acting along the stacking direction at least is indirectly acted upon. As a result, the force can be exerted, for example, along a straight line and thus particularly advantageously on the storage cells, so that the force can be kept at least essentially constant even when the volume of the storage cells changes.

In a further, particularly advantageous embodiment of the invention, it is provided that the storage cells are arranged in a housing element. In this case, the piston element can be moved relative to the housing and relative to the housing element, in particular in a translatory manner. The housing element is, for example, a storage or module housing of the energy store.

It has proven to be particularly advantageous if on a second side of the cell stack facing away from the first side along the stacking direction there is a stop which is fixed at least along the stacking direction relative to the housing element and is therefore immovable and on which the storage cells are at least indirectly supported along the stacking direction are. The force provided by the cylinder device via its housing or its piston element can thus be transmitted to the storage cells in particular along the stacking direction and can act on the storage cells in particular along the stacking direction and can be transmitted from the storage cells or from the cell stack along the stacking direction to the stop and thus to the Stop and are supported by this on the housing element, so that the storage cells can be particularly advantageously applied with the force. The storage cells can thus be held against one another or held together particularly advantageously by means of the force, it being possible for the force to be kept at least essentially constant, in particular even when there are changes in the volume of the storage cells.

Alternatively, it would be conceivable for a second cylinder device to be arranged on the second side, in which case the previous and following statements relating to the first cylinder device can easily also be applied to the second cylinder device and vice versa. Whenever the cylinder device is mentioned below, this is to be understood as meaning the first cylinder device, unless otherwise stated.

It is conceivable that the housing and the housing element are designed in one piece with each other. Preferably, however, it is provided that the housing and the housing element are components formed separately from one another, with the housing for example being able to be arranged at least partially, in particular at least predominantly and thus at least more than half or completely in the housing element. Alternatively or additionally, the piston element can be arranged at least partially, in particular at least predominantly or completely, in the housing element.

In order to be able to implement a particularly advantageous operation of the energy store, it is provided in a further embodiment of the invention that the respective storage cell is designed as a solid-state accumulator, that is to say as a solid-state cell. The respective storage cell comprises, for example, at least or precisely two electrodes and an electrolyte, in particular for transporting and/or conducting charge carriers. The solid-state accumulator is characterized in that the or all electrodes of the solid-state accumulator and also the electrolyte of the solid-state accumulator is solid, that is to say it is a solid body or is formed from a solid material. Provision is therefore preferably made for the respective storage cell, in particular the energy store as a whole, to be in the form of an all-solid-state battery, and therefore as a solid-state accumulator. This embodiment is based in particular on the knowledge that, particularly in the case of solid-state accumulators, there are major changes or fluctuations in the external dimensions during charging and discharging.

It is conceivable that the cylinder device is a pressure cylinder which, for example, provides the force as a pressure force. It is thus conceivable that the force acts as a compressive force on the storage cells. It is also conceivable that the cylinder device is designed as a so-called pull cylinder, which provides the force, for example, as a pull force. It is thus conceivable that the force acts as a tensile force on the storage cells, or that the tensile force results in a compressive force that acts on the storage cells.

In order to keep the force at least essentially constant even when the volume of the storage cells changes and thus to be able to ensure particularly advantageous operation of the energy storage device, it is provided in a further embodiment of the invention that the fluid is an in particular incompressible liquid. In other words, it is preferably provided that the energy store comprises the fluid, and therefore the fluid is a component of the energy store, with preference as the fluid is a liquid. The cylinder device is thus preferably designed as a hydraulic cylinder, by means of which the force can be kept at least substantially constant, particularly advantageously. In addition, a sufficiently high level of force can be secured. A further advantage is that the force or the pressure acting on the storage cells can be set particularly precisely, in particular regulated or adjusted, by means of the hydraulic cylinder, so that excessive fluctuations in the force or the pressure can be avoided even when there are large changes in the volume of the storage cell.

The cylinder device is designed, for example, as a push or pull cylinder, similar to the one used, for example, in a brake caliper of a brake system of a motor vehicle, in particular a motor vehicle, designed in particular as a service brake. The fluid can be provided in particular by means of a central device, in particular a hydraulic device, or the piston element and/or the housing can be subjected to the fluid and thus to its pressure, so that the cylinder device can provide the force via the piston element and/or the housing. A number of cylinder devices per storage device, in particular per storage module, can depend on the respective size of the respective storage cell and/or on an arrangement of the storage cells and/or the respective cylinder device in the energy store or in the module.

Finally, it has proven particularly advantageous if the piston element is a first component of the cylinder device and the housing is a second component of the cylinder device. In other words, the piston element is also referred to as the first component and the housing is also referred to as the second component. Provision is preferably made for a cushion that is at least partially filled with a liquid, a gas or preferably a gel to be arranged along the stacking direction between at least one of the components and at least one of the storage cells. In particular when the cushion is filled with a gel, the cushion is also referred to as a gel cushion. It is also provided that the force provided by the cylinder device can be transmitted to the at least one storage cell via the cushion. As a result, changes in the volume of the storage cells can be compensated for in a particularly advantageous manner, and the force can be kept at least essentially constant. A particularly advantageous operation of the energy store can be ensured in this way.

A second aspect of the invention relates to a motor vehicle, preferably designed as a motor vehicle, in particular a passenger car, which has at least one electrical energy store according to the first aspect of the invention. Advantages and advantageous configurations of the first aspect of the invention are to be regarded as advantages and advantageous configurations of the second aspect of the invention and vice versa.

Further details of the invention result from the following description of a preferred exemplary embodiment with the associated drawing. It shows the only 1 a detail of a schematic sectional view of an electrical energy store according to the invention for storing electrical energy for a motor vehicle.

1 shows a detail of an electrical energy store 1 for a motor vehicle in a schematic sectional view. This means that the motor vehicle, which is preferably designed as a motor vehicle, in particular as a passenger car, has the energy store 1, by means of which electrical energy or electrical current can be stored or stored. The motor vehicle is preferably designed as a hybrid or electric vehicle, in particular as a battery-electric vehicle, and thus comprises at least one electric machine, by means of which the motor vehicle can be driven, in particular purely electrically. In order to drive the motor vehicle by means of the electric machine, the electric machine is operated in a motor mode and thus as an electric motor. For this purpose, the electrical machine is supplied with the electrical energy stored in the energy store 1 .

The energy store 1 comprises a storage housing 2, also referred to as a housing element, which forms or, in particular directly, delimits a receiving space 3. In addition, the energy store 1 includes storage cells 4a, b, by means of or in which the electrical energy, in particular electrochemically, is to be stored or stored. Out of 1 it can be seen that the memory cells 4a along an in 1 are arranged in succession, ie one behind the other, in the stacking direction illustrated by a double arrow 5 and thereby form a first cell stack 6a. The memory cells 4b are arranged in succession along the stacking direction and thereby form a second cell stack 6b. The cell stacks 6a, b are spaced apart from one another along the stacking direction. The storage cells 4a, b and thus the cell stacks 6a, b are arranged in the receiving space 3 and thus in the storage housing 2 (housing element). It is preferably provided that the respectively all storage cells 4a, b are designed as solid-state accumulators, so that it is preferably provided that the energy store 1 is designed as a whole as a solid-state accumulator. This means in particular that the respective storage cell 4a, b, in particular the energy store 1 as a whole, is completely free of a liquid electrolyte for transporting electrical charge carriers.

Furthermore is off 1 recognizable that the respective storage cell 4a, b and thus the respective cell stack 6a, b as a whole has a respective outer dimension running along the stacking direction, which is also referred to as the outer dimension. Particularly in the case of charging and discharging processes, in which the storage cells 4a, b are charged and discharged, major changes, ie major fluctuations, in the external dimensions can occur. These fluctuations or changes in the external dimensions are also referred to as volume fluctuations or volume changes.

In order to now be able to implement a particularly advantageous operation of the energy store 1, the energy store 1 has at least one cylinder device 7, which in 1 shown embodiment is arranged in the storage housing 2. The cylinder device 7 has a housing 8 and a piston element 9 , also referred to simply as a piston, which is partly accommodated in the housing 8 and partly protrudes from the housing 8 , and is therefore partly arranged outside the housing 8 . Thus, the housing 8 is also referred to as a piston receptacle or cylinder. The cylinder device 7 also has a working chamber 10 which is in each case partially delimited by the piston element 9 and the housing 8, in particular directly in each case, and in which a fluid can be received or is present. The fluid is preferably a liquid.

The working chamber 10 can, in particular via at least or exactly one in 1 connecting channel, not shown, with an in 1 compensation chamber not shown be fluidically connected or connectable, the compensation chamber being formed, for example, by an expansion tank or, in particular directly, limited. The compensating chamber is arranged outside of the working chamber 10 . The piston element 9 is along an in 1 The direction of movement illustrated by a double arrow 11 relative to the housing 8 can be moved in a translatory manner, and is therefore displaceable. The double arrows 5 and 11 show that the direction of movement runs parallel to the stacking direction or coincides with the stacking direction. If the piston element 9 relative to the housing 8 in an in 1 illustrated by an arrow 12 and running parallel to the direction of movement, at least a part of the piston element 9 initially arranged outside of the housing 8 is moved into the housing 8, causing a reduction in the volume of the working chamber 10. As a result, for example, at least part of the fluid initially received in the working chamber 10 is conveyed out of the working chamber 10 in particular via the connecting channel and conveyed, for example, into the compensation chamber and subsequently received in the compensation chamber. If, on the other hand, for example, the piston element 9 is inserted into an in 1 illustrated by an arrow 13, runs parallel to the direction of movement and is opposite to the first direction, in a translatory manner relative to the housing 8, at least a part of the piston element 9 initially accommodated in the housing 8 is moved out of the housing 8, resulting in an increase in volume the working chamber 10 is effected. As a result, for example, at least a part of the fluid initially taken outside of the working chamber 10 and, for example, in the equalizing chamber is conveyed out of the equalizing chamber in particular and into the working chamber 10 in particular, in particular sucked in, in particular via the connecting channel. In particular, it is conceivable that when the volume of the working chamber 10 decreases or increases in volume, a pressure of the fluid prevailing in the working chamber 10 remains constant.

The piston element 9 is also referred to as the first component of the cylinder device 7 , and the housing 8 is also referred to as the second component of the cylinder device 7 . The pressure of the fluid in the working chamber 10 results in a respective force acting on the respective component, in particular along the stacking direction, which can be provided by the cylinder device 7 via the respective component, in particular along the stacking direction. Out of 1 It is particularly easy to see that the respective force acting along the stacking direction can be or is provided by means of the cylinder device 7, with the respective force acting along the stacking direction on the respective cell stack 6a, b and thus on its storage cells 4a, b. For example, the housing 8 and thus the cylinder device 7 as a whole are mounted floating on the accumulator housing 2 at least along the stacking direction, so that the housing 8 can be moved translationally along the stacking direction or along the direction of movement relative to the piston element 9 and relative to the accumulator housing 2, and the piston element 9 can be moved translationally along the stacking direction or along the movement direction relative to the housing 8 and relative to the storage housing 2 . If, for example, there is an increase in the external dimensions of the cell stack 6b, the housing 8 is moved in a translatory manner relative to the piston element 9 and relative to the accumulator housing 2 in the second direction illustrated by the arrow 13. If, alternatively or additionally, the outer dimensions of the cell stack 6a increase, then for example the piston element 9 is moved in a translatory manner relative to the accumulator housing 2 and relative to the housing 8 in the first direction illustrated by the arrow 12 . If the respective outer dimension decreases again, for example the housing 8 or the piston element 9 is moved in the first direction or in the second direction relative to the respective other component and relative to the accumulator housing 2 . Since at least part of the fluid is discharged from the working chamber 10 and introduced into the working chamber 10, so that the pressure of the fluid in the working chamber 10 remains at least essentially constant, the respective pressure provided by the cylinder device 7 via the respective component and along it remains The force acting on the respective cell stack 6a, b in the stacking direction is at least essentially constant when there are changes in the external dimensions of the storage cells 4a, b and thus of the cell stack 6a, b. As a result, a desired, advantageous function of the energy store 1 can be guaranteed even in the event of strong fluctuations or changes in the external dimensions.

For example, the housing 8 is mounted in a floating manner on the storage housing 2 via a pressure plate 14, so that the housing 8 can be moved translationally along the stacking direction or along the direction of movement relative to the storage housing 2. It can be provided that the pressure plate 14, which is formed separately from the housing 8 and separately from the storage housing 2, is fixed to the storage housing 2 at least along the direction of movement or stacking direction or is immovable relative to the storage housing 2.

The storage housing 2 comprises, for example, a first housing part 15 and a second housing part 16. The housing parts 15 and 16 are, for example, formed separately from one another and connected to one another. For example, the housing part 15 is a housing cover, while the housing part 16 can be a housing base. It can be seen that the receiving space 3 is in each case partially delimited by the housing parts 15 and 16, in particular directly.

Furthermore, it can be seen that the cylinder device 7 follows the respective cell stack 6a, b along the stacking direction. At the in 1 shown embodiment, the cylinder device 7 is a central cylinder device, which is arranged along the stacking direction between the cell stacks 6a, b. The force provided by the cylinder device 7 is exerted by the cylinder device 7 via the housing 8 on the cell stack 6b and thus on the storage cells 4b and via the piston element 9 on the cell stack 6a and thus the storage cells 4a.

The cylinder device 7 is arranged on a respective first side S1 of the respective cell stack 6a, b, so that the respective first side S1 of the respective cell stack 6a, b can be or is acted upon by the force provided by the cylinder device 7 and acting along the stacking direction . On a respective second side S2 of the respective cell stack 6a, b, facing away from the respective first side S1 along the stacking direction, there is at least one respective stop 17a, b, fixed at least along the stacking direction relative to the storage housing 2 (housing element), on which the respective cell stacks 6a, b and thus the memory cells 4a, b are at least indirectly supported along the stacking direction. The force exerted from the respective cell stack 6a, b can thus be transmitted via the respective stop 17a, b to the storage housing 2 and thus supported, so that the storage cells 4a, b can be pressed together or held together in a particularly advantageous manner by means of the respective force, in particular also when there are major changes or fluctuations in the external dimensions. Since the fluid is a liquid, the cylinder device 7 is a hydraulic cylinder, which is part of a hydraulic system, for example. By means of the hydraulic system, the pressure of the fluid and thus the force can be set particularly precisely, in particular regulated, so that the force can advantageously be kept at least essentially constant even in the event of strong fluctuations in the external dimensions.

At least one pressure plate 18a, b can be arranged in the respective cell stack 6a, b, which is arranged between two adjacent storage cells 4a, b of the respective cell stack 6a, b along the stacking direction. It is also conceivable that a cushion 19a, b is arranged along the stacking direction between the cylinder device 7, in particular between the piston element 9, and at least one of the storage cells 4a, in particular the cell stack 6a, which cushion is at least partially, in particular at least predominantly or completely is filled with a gel and thus is designed as a gel pad. The force provided by the cylinder device 7, in particular via the piston element 9, can be transmitted via the gel cushion to the respective storage cell 4a or to the cell stack 6a. Alternatively or additionally, it is conceivable for a cushion 20a, b to be arranged along the stacking direction between the cylinder device 7, in particular between the housing 8, and at least one of the storage cells 4b, in particular the cell stack 6b, which cushion is at least partially, in particular at least predominantly or complete, filled with a gel and thus designed as a gel cushion. As already described with regard to the cushion 19a, b, the force provided by the cylinder device 7, in particular via the housing 8, can be transmitted via the respective cushion 20a, b to the respective storage cell 4b or to the cell stack 6b. By using the cushions 19a, b and 20a, b, the force can be transferred to the storage cells 4a, b in a particularly advantageous manner, and the force can be kept at least essentially constant in a particularly advantageous manner.

Reference List

1

electrical energy storage

2

storage enclosure

3

recording room

4a, b

storage cells

5

double arrow

6a, b

cell stack

7

cylinder setup

8th

Housing

9

piston element

10

working chamber

11

double arrow

12

Arrow

13

Arrow

14

printing plate

15

housing part

16

housing part

17a, b

attack

18a, b

printing plate

19a, b

pillow

20a, b

pillow

S1

first page

S2

second page

QUOTES INCLUDED IN DESCRIPTION

This list of documents cited by the applicant was generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Patent Literature Cited

• WO 2017/133856 A1 [0002]
• WO 2012/097980 A1 [0002]
• WO 2010/081704 A2 [0002]

Claims (10)

Electrical energy store (1) for storing electrical energy for a motor vehicle, having a plurality of storage cells (4a, b) arranged one after the other along a stacking direction (5) for storing electrical energy, characterized by at least one housing (8), one relative to The piston element (9) that can be moved in the housing (8) and at least one working chamber (10), which is in each case partially delimited by the piston element (9) and the housing (8), for receiving a fluid, having a cylinder device (7), by means of which a cylinder device (7) along the stacking direction (5 ) At least indirectly acting on the storage cells (4a, b) force can be brought about. Electrical energy storage device (1) according to claim 1 , characterized in that the piston element (9) is translationally movable along the stacking direction (5) relative to the housing (8). Electrical energy storage device (1) according to claim 1 or 2 , characterized in that the cylinder device (7) follows the storage cells (4a, b) along the stacking direction (5). Electrical energy storage device (1) according to claim 3 , characterized in that the storage cells (4a, b) form a cell stack (6a, b), wherein the cylinder device ( 7) is arranged on a first side (S1) of the cell stack (6a, b), which can be acted upon by the force exerted by means of the cylinder device (7) via its first side (S1). Electrical energy storage device (1) according to claim 4 , characterized in that the storage cells (4a, b) are arranged in a housing element (2), the piston element (9) being movable relative to the housing (2) and relative to the housing element (2). Electrical energy storage device (1) according to claim 5 , characterized in that on a second side (S2) of the cell stack (6a, b) facing away from the first side (S1) along the stacking direction (5) there is a stop ( 17a, b), on which the memory cells (4a, b) are at least indirectly supported along the stacking direction (5). Electrical energy store (1) according to one of the preceding claims, characterized in that the respective storage cell (4a, b) is a solid-state accumulator. Electrical energy store (1) according to one of the preceding claims, characterized in that the fluid is a liquid. Electrical energy store (1) according to one of the preceding claims, characterized in that the piston element (9) is a first component of the cylinder device (7) and the housing (8) is a second component of the cylinder device (7), wherein along the stacking direction (5th ) a cushion (19a, b, 20a, b) at least partially filled with a liquid, a gas or a gel is arranged between at least one of the components and at least one of the storage cells (4a, b), via which the cushion (19a, b, 20a, b) is transported by means of the cylinder device (7 ) Effected force can be transferred to the at least one storage cell (4a, b). Motor vehicle with at least one electrical energy store (1) according to one of the preceding claims.

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