A battery module for an electrical energy storage device for a motor vehicle, an electrical energy storage device, and a method

Abstract

A battery module 10, for an electrical energy storage device 12 of a motor vehicle, comprises several energy storage elements 14, a pressure supply device 28, by which the energy storage elements 14 a

Description

FIELD OF THE INVENTION

[0001] The present invention relates to the field of automobiles. More specifically, the present invention relates to a battery module for an electrical energy storage device of a motor vehicle. Furthermore, the present invention relates to a corresponding energy storage device for a motor vehicle and a method for operating a corresponding battery module. BACKGROUND INFORMATION

[0002] In the state of the art, a battery module, which might be designed as a battery pack, comprises several battery cells. The said battery cells may expand and contract upon charge or discharge and may be integrated in the battery pack using some sort of mechanical mechanism to accommodate the volume change. At the same time, a relatively high stack pressure, for example between 50 kilopascal and 3 megapascal, may be applied as it usually may be beneficial for cell performance. In a thermal event, for example triggered by damage of a cell from the outside, this set-up known from the state of the art may not be beneficial because heat may travel easily from the battery cell with the thermal event to the next battery cell. SUMMARY OF THE INVENTION

[0003] It is an object of the present invention to provide a battery module for an electrical energy storage device of a motor vehicle, a corresponding electrical energy storage device for a motor vehicle, as well as a method for operating a battery module for an electrical energy storage device of a motor vehicle, by which safety of the battery module can be particularly increased.

[0004] This object is solved by a battery module for an electrical energy storage device of a motor vehicle, a corresponding electrical energy storage device for a motor vehicle, as well as a method for operating a battery module for an electrical energy storage device of a motor vehicle according to the independent claims. Advantageous embodiments are presented in the dependent claims.

[0005] One aspect of the invention relates to a battery module for an electrical energy storage device of a motor vehicle. Preferably, the motor vehicle is designed as a passenger car. Preferably, the motor vehicle is a battery electric vehicle (BEV) or a hybrid vehicle, in particular a plug-in hybrid vehicle (PHEV). The energy storage device may be understood as an accumulator or a battery respectively, which may be referred to as storage battery.

[0006] The battery module comprises several energy storage elements, which are preferably designed as storage cells. The said storage cells may be referred to as battery cells. Therefore, the battery module may be referred to as cell module or cell pack. Preferably, the battery module is designed as a cell array.

[0007] Furthermore, the battery module comprises at least one pressure supply device, by which the energy storage elements are capable of being pressurized or are pressurized. The said pressurization of the energy storage elements may be referred to as stack pressure. This means that the pressure supply device is capable of generating the stack pressure. The pressure supply device is also capable of reducing the said pressure.

[0008] In particular, to increase safety of the battery module, for example safety against the thermal event, the energy storage elements are, in particular directly, coupled to each other via a coupling element. In other words, the energy storage elements are connected mechanically with each other via the coupling element. The coupling element is designed as a string which is capable of being, in particular elastically, deformed from a normal state to a stretched state. This means that the coupling element may chance its shape between the normal state and the stretched shape. A length of the coupling element or the string, respectively, is in the stretched state longer than in the normal state. A reduction of the said pressurization of the storage elements caused by the pressure supply device is accompanied by an increase of a respective distance between two respective adjacent energy storage elements. This means that the pressure supply device is capable of reducing the stack pressure, whereby the energy storage elements are moved away from each other. As a result, there is the said increase of the respective distance between the energy storage elements. In other words, the said reduction of the pressurization by the pressure supply device effects the increase of the distances between the energy storage elements. The said respective distance may be referred to as spacing, gap or clearance. The said respective distance is larger after the said pressure reduction. This means that the said distance in a first state of the battery module comprises a first value and in a second state of the battery module comprises a second value that is larger than the first value, wherein a change from the first state to the second state is effected by the reduction of the said pressurization caused by the pressure supply device.

[0009] Furthermore, the said reduction of the pressurization of the energy storage elements caused by the pressure supply device is accompanied by the deformation of the coupling element from the normal state to the stretched state. This means that the pressure supply device is capable of reducing the stack pressure, whereby the coupling element is deformed from the normal state to the stretched by the said movement of the energy storage elements. In other words, the said reduction of the pressurization by the pressure supply device effects the deformation of the coupling element from the normal state to the stretched state. In the stretched state the coupling element is force-loaded by the energy storage elements in order to control the said respective distance, in particular to ensure equality of the distances between the energy storage elements. This means that the increase of the said distances is controlled or adjusted by the coupling element, in particular in the stretched state. Preferably, the coupling element is in its normal state in the first state of the battery module and is in its stretched state in the second state of the battery module.

[0010] In the present invention, it may be possible to actively create the said spacing, in particular to increase the said spacing, between the energy storage elements due to the said pressure reduction. This may be triggered by a high temperature condition detected by an electronic computing device or automatically triggered by an independent mechanism. The electronic computing device may be designed as a battery management system. For example, the battery management system may detect a battery condition that may indicate a thermal event such as a thermal runaway event. The battery management system may utilize artificial intelligence and / or other processes to determine a thermal event such as a high temperature after detecting an abnormal pressure or another battery condition. The invention is based in particular on the recognition that the material between cells does not need to be a thermal barrier, which may require more space and may lead to inferior thermal properties during normal operation. Only in the event of a problem, for example, the said thermal event, the battery cells can be put in a thermally much more separated configuration, in particular in the said second state. Due to the increase of the distance between the storage elements, heat transfer between the storage elements may be reduced, for example in case of the thermal event. Therefore, an unsafe chain reaction between the storage elements may be avoided securely. In other words, thermal propagation between the storage elements may be avoided securely. As soon as the stack pressure is removed the energy storage elements may be further separated because the reversed pressure “pulls” on the energy storage elements. The energy storage elements, in particular all of the energy storage elements, are mechanically linked to each other by the said coupling element. Therefore, equal spacing between the energy storage elements may be assured in the stretched state or the second state, respectively. So, the coupling element is capable of holding the separated energy storage elements together in a predefined distance, in particular uniformly spaced from each other. Besides the string, no additional parts may be needed and the electrical cell connectors of the battery module might already provide a function to hold cells in similar distances once the stack pressure actuator reverses from positive to negative pressure.

[0011] It is therefore intended that with the present invention in case of a safety problem, the energy storage elements may be placed in a beneficial state for no thermal propagation. This could apply for any battery assembly even with cylindrical cells, prismatic or pouch cells, and it may not depend on the set up described. Overall, it is recognizable that an on-event battery cell spacing with a string may be provided.

[0012] According to an embodiment the battery module comprises at least one temperature sensor and an electronic computing device by which the pressure supply device is capable of being controlled or is controlled as a function of a temperature detected by the temperature sensor in order to effect the said increase of the respective distance or the deformation of the coupling element from the normal state to the stretched state, respectively.

[0013] In another embodiment, the energy storage elements are arranged between two end plates, wherein the energy storage elements are capable of being pressurized or are pressurized by the pressure supply device via at least one of the end plates.

[0014] In another embodiment, the coupling element is designed as an electrical connector. Preferably, the energy storage elements are connected electrically with each other via the electrical connector or the coupling element respectively.

[0015] In another embodiment, the coupling element is designed to be heat resistant.

[0016] In another embodiment, the coupling element is designed to be fire resistant.

[0017] In another embodiment, at least three, in particular at least four, six or eight, of the energy storage elements are coupled to each other, in particularly mechanically and / or electrically, via the said coupling element.

[0018] Another aspect of the present invention relates to an energy storage device for a motor vehicle, comprising at least the battery module according to the first aspect of the invention. Advantageous embodiments of the electrical energy storage device are to be regarded as advantageous embodiments of the battery module and vice versa.

[0019] Another aspect of the present invention relates to a method for operating a battery module, in particular according to the first aspect of the invention, for an energy storage device, in particular according to the second aspect of the invention, of a motor vehicle. Advantageous embodiments of the method are to be regarded as advantageous embodiments of the battery module and the electrical energy storage device and vice versa.

[0020] A still further aspect of the present invention relates to a computer program product comprising program code means for performing a method according to the preceding aspect.

[0021] Furthermore, the present invention relates to a non-transitory computer-readable storage medium comprising at least the computer program product according to the preceding aspect.

[0022] A computing unit / electronic computing device may in particular be understood as a data processing device, which comprises processing circuitry. The computing unit can therefore in particular process data to perform computing operations. This may also include operations to perform indexed accesses to a data structure, for example a look-up table, LUT.

[0023] In particular, the computing unit may include one or more computers, one or more microcontrollers, and / or one or more integrated circuits, for example, one or more application-specific integrated circuits, ASIC, one or more field-programmable gate arrays, FPGA, and / or one or more systems on a chip, SoC. The computing unit may also include one or more processors, for example one or more microprocessors, one or more central processing units, CPU, one or more graphics processing units, GPU, and / or one or more signal processors, in particular one or more digital signal processors, DSP. The computing unit may also include a physical or a virtual cluster of computers or other of said units.

[0024] In various embodiments, the computing unit includes one or more hardware and / or software interfaces and / or one or more memory units.

[0025] A memory unit may be implemented as a volatile data memory, for example a dynamic random access memory, DRAM, or a static random access memory, SRAM, or as a non-volatile data memory, for example a read-only memory, ROM, a programmable read-only memory, PROM, an erasable programmable read-only memory, EPROM, an electrically erasable programmable read-only memory, EEPROM, a flash memory or flash EEPROM, a ferroelectric random access memory, FRAM, a magnetoresistive random access memory, MRAM, or a phase-change random access memory, PCRAM.

[0026] The battery module comprises several energy storage elements and at least one pressure supply device, by which the energy storage elements are pressurized.

[0027] In order to increase safety of the battery module, in particular against the thermal event, the energy storage elements are coupled to each other via a coupling element, which is designed as a string capable of being deformed from a normal state to a stretched state. The said pressurization of the storage elements is reduced by the pressure supply device. As a result, a respective distance between two respective adjacent energy storage elements is increased and the coupling element is deformed from the normal state to the stretched state, in which the coupling element is force-loaded by the energy storage elements in order to control the said respective distance.

[0028] Further advantages, features, and details of the present invention derive from the following description of preferred embodiments as well as from the drawings. The features and feature combinations previously mentioned in the description as well as the features and feature combinations mentioned in the following description of the figures and / or shown in the figures alone can be employed not only in the respectively indicated combination but also in any other combination or taken alone without leaving the scope of the invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] The novel features and characteristic of the present disclosure are set forth in the appended claims. The accompanying drawings, which are incorporated in and constitute a part of this disclosure, illustrate exemplary embodiments and together with the description, serve to explain the disclosed principles. In the figures, the left-most digit(s) of a reference number identifies the figure in which the reference number first appears. The same numbers are used throughout the figures to reference like features and components. Some embodiments of system and / or methods in accordance with embodiments of the present subject matter are now described below, by way of example only, and with reference to the accompanying figures.

[0030] The drawings show in:

[0031] Fig. 1 a schematic side view of an embodiment of a battery module, wherein a coupling element is in a normal state;

[0032] Fig. 2 a partial schematic view of an embodiment of a battery module, wherein a coupling element is in a normal state; and

[0033] Fig. 3 a schematic side view of an embodiment of a battery module, wherein a coupling element is in a stretched state.

[0034] In the figures the same elements or elements having the same function are indicated by the same reference signs. DETAILED DESCRIPTION

[0035] In the present document, the word "exemplary" is used herein to mean "serving as an example, instance, or illustration". Any embodiment or implementation of the present subject matter described herein as "exemplary" is not necessarily to be construed as preferred or advantageous over other embodiments.

[0036] While the present disclosure is susceptible to various modifications and alternative forms, specific embodiments thereof have been shown by way of example in the drawing and will be described in detail below. It should be understood, however, that it is not intended to limit the disclosure to the particular forms disclosed, but on the contrary, the disclosure is to cover all modifications, equivalents, and alternatives falling within the scope of the disclosure.

[0037] The terms “comprises”, “comprising”, or any other variations thereof, are intended to cover a non-exclusive inclusion so that a setup, device or method that comprises a list of components or steps does not include only those components or steps but may include other components or steps not expressly listed or inherent to such setup or device or method. In other words, one or more elements in a system or apparatus preceded by “comprises” or “comprise” does not or do not, without more constraints, preclude the existence of other elements or additional elements in the system or method.

[0038] In the following detailed description of the embodiment of the present disclosure, reference is made to the accompanying drawing that forms part hereof, and in which is shown by way of illustration a specific embodiment in which the disclosure may be practiced. This embodiment is described in sufficient detail to enable those skilled in the art to practice the disclosure, and it is to be understood that other embodiments may be utilized and that changes may be made without departing from the scope of the present disclosure. The following description is, therefore, not to be taken in a limiting sense.

[0039] Fig. 1 shows a schematic side view according to an embodiment of a battery module 10 for an electrical energy storage device 12 of a motor vehicle. The said side view in Fig. 1 may be a sectional view. The motor vehicle is preferably at least in part electrically operated or full electrically operated. Therefore, the motor vehicle may comprise at least one electric motor. Preferably, the electric motor is supplied with energy by the electrical energy storage device 12, in particular by the battery module 10. For example, the electrical energy storage device 12 is designed as a battery, in particular, a low voltage or a high voltage battery. A high voltage battery may be 60V to 1500V.

[0040] The battery module 10 comprises several energy storage elements 14. Preferably, the energy storage elements 14 are cells, which may be referred to as battery cells. The battery module 10 is capable of executing a method for operating the battery module 10. For example, the respective battery cell is designed as a cylindrical cell, a prismatic cell, or a pouch cell.

[0041] Furthermore, the battery module 10 comprises a pressure supply device 28 by which the energy storage elements 14, are capable of being pressurized or are pressurized. In other words, the said pressure supply device 28 is capable of applying a force in order to effect the said pressurization of the storage elements 14. The pressure supply device 28 may be referred to as pressure generating device or stack pressure generating device.

[0042] In order to increase safety of the battery module 10, preferably safety against the thermal event, the energy storage elements 14 are coupled to each other via a coupling element 16, which is designed as a string 17 as shown in Fig. 1 in the normal state 18. This can be seen in Fig. 2, which shows a partial schematic view of the battery module 10 for the energy storage device 12, respectively. The coupling element 16 is capable of being deformed from a normal state 18 to a stretched state 20. A reduction of the said pressurization of the storage elements 14 caused by the pressure supply device 28 is accompanied by an increase of a respective distance between two respective adjacent energy storage elements 14 and by the deformation of the coupling element 16 from the normal state 18 to the stretched state 20. Fig. 1 and Fig. 2 show the battery module 10 in a first state, in particular before the said increase of the respective distance between the energy storage elements 14. In the said first state the coupling element 16 is in the normal state 18. This is shown in Fig. 2. In contrast, Fig. 3 shows the battery module 10 in a second state or stretched state 20, in which the said increase of the distances between the storage elements 14 has already taken place. This means that the said increase of the distances is illustrated in Fig. 3. In the second state, the coupling element 16 is in its stretched state 20. In the stretched state 20 the coupling element 16 is force-loaded by the energy storage elements 14 in order to control the said respective distance. This may result in a uniform distance between the energy storage elements 14 after they have moved away from each other due to the said pressure reduction. As a result, heat transfer between the storage elements 14 may be reduced. Preferably, the coupling element 16 is not force loaded by the energy storage elements 14 in the normal state 18 or the first state, respectively.

[0043] As shown in Fig. 2 and 3, the storage elements 14 and the coupling element 16 are formed separately from each other. In the example shown in Fig. 2 and 3 the energy storage elements 14, in particular all the energy storage elements 14, are mechanically linked by threads, in particular in such a way equal spacing between the energy storage elements 14 is assured. The threads are formed from the coupling element 16 or the string 17, respectively. Preferably, the coupling element 16, in particular the respective threads, is directly attached to the energy storage elements 14. Two respective adjacent energy storage elements 14 are attached to each other via the coupling element 16. The distances between the energy storage elements 14 may be filled at least partially with inter-cell material 22. Preferably, the coupling element 16 is made of a flexible material.

[0044] It becomes clear that the pressure supply device 28 is designed as an activation device which is capable of effecting, in particular initiating, the said displacement of the coupling element 16 from the normal state 18 to the stretched 20. So, a first step to effect the said displacement may be the reduction of the said pressurization or stack pressure 30 of the energy storage elements 14, respectively. “Reduction” may be understood as a removal of the pressure 30 at least partially or completely. The displacement may be implemented by pressure supply device 28 applying a reverse pressure 31, which “pulls” on the energy storage elements 14.

[0045] In the embodiment shown in Fig. 1 and 2, the energy storage device 12, in particular the battery module 10, comprises at least one temperature sensor 24 and an electronic computing device 26 by which the pressure supply device 28 is capable of being controlled as a function of a temperature detected by the temperature sensor 24 in order to effect the said displacement of the respective distance or the movement of the energy storage elements 14, respectively. This means that the temperature sensor 24 may detect the said temperature, and the said electronic computing device 26 may control the pressure supply device 28 as a function of the detected temperature in order to effect the said increase of the distances between the energy storage elements 14. As a result, it may be possible to move the energy storage elements 14 as a function of the detected temperature.

[0046] The electronic computing device 26 may be understood as a data processing device, which comprises processing circuitry. Therefore, the electronic computing device 26 may be referred to as a computing unit. The electronic computing device 26 may, in particular, process data to perform computing operations. This may also include operations to perform indexed accesses to a data structure.

[0047] In particular, the electronic computing device 26 may include one or more computers, one or more microcontrollers, and / or one or more integrated circuits, for example, one or more application-specific integrated circuits, ASIC, one or more field-programmable gate arrays, FPGA, and / or one or more systems-on-a-chip, SoC. The electronic computing device 26 may also include one or more processors, for example one or more microprocessors, one or more central processing units, CPU, one or more graphics processing units, GPU, and / or one or more signal processors, in particular one or more digital signal processors, DSP. The electronic computing device 26 may also include a physical or a virtual cluster of computers or other ones of said units.

[0048] In various embodiments, the electronic computing device 26 includes one or more hardware and / or software interfaces and / or one or more memory units. A memory unit may be implemented as a volatile data memory, for example a dynamic random access memory, DRAM, or a static random access memory, SRAM, or as a non-volatile data memory, for example a read-only memory, ROM, a programmable read-only memory, PROM, an erasable programmable read-only memory, EPROM, an electrically erasable programmable read-only memory, EEPROM, a flash memory or flash EEPROM, a ferroelectric random access memory, FRAM, a magnetoresistive random access memory, MRAM, or a phase-change random access memory, PCRAM.

[0049] In the embodiment shown in Fig. 1 to 3, the storage elements 14 are arranged between two end plates 32, 34, wherein the storage elements 14 are capable of being pressurized or pressurized by the pressure supply device 28 via at least one of the end plates 32, 34. This means that the storage elements 14 are force-loaded, in particular pressure loaded, by the pressure supply device 28 via at least one of the said end plates 32, 34. This is illustrated in Fig. 1 by respective pressure 30 arrows. In other words, the said pressure supply device 28 is capable of applying a force to at least one of the end plates 32, 34, in order to generate the said pressure 30. In the example in Fig. 1 to 3, a first one of the end plates 32 is designed as a mechanical support, and the second one of the end plates 34 is capable of being moved and is force loaded by the pressure supply device 28. The said reduction of the pressure is illustrated in Fig. 3 by a reverse pressure 31 arrow. Preferably, the coupling element 16 is attached at least to one of the end plates 32, 34, in particular directly.

[0050] Preferably, the coupling element 16 is heat resistant and / or fire resistant. A string can be made heat or fire resistant without adding much cost.

[0051] In an embodiment, the coupling element 16 is designed as an electrical connector. For example, the coupling element 16 is at least partially made of cell connectors, via which the energy storage elements 14 are connected with each other electrically. The cell connector may be referred to as electrical terminal. In some module 10 designs, the present invention may be implemented using electrical terminals with flexible conductive connectors as the string 17 (flexible connection) for the battery cells 14. These electrical cell connections may be sufficient for the battery module 10 to produce the distributed spacing upon pressure reduction of pressure 30 or reversal with reverse pressure 31. reference signs battery module energy storage device energy storage element coupling element string normal state stretched state inter-cell material temperature sensor electronic computing device pressure supply device pressure reverse pressure first end plate second end plate

Claims

1. A battery module (10) for an electrical energy storage device (12) of a motor vehicle, comprising several energy storage elements (14), a pressure supply device (28), by which the energy storage elements (14) are capable of being pressurized or are pressurized, characterized in thatthe energy storage elements (14) are coupled to each other via a coupling element (16) which is designed as a string (17) capable of being deformed from a normal state (18) to a stretched state (20), wherein a reduction of the said pressurization of the storage elements (14) caused by the pressure supply device (28) is accompanied by an increase of a respective distance between two respective adjacent energy storage elements (14) and by the deformation of the coupling element (16) from the normal state (18) to the stretched state (20), in which the coupling element (16) is force-loaded by the energy storage elements (14) in order to control the said respective distance.

2. The battery module (10) according to claim 1, characterized in thatthe battery module (10) comprises at least one temperature sensor (24) and an electronic computing device (26) by which the pressure supply device (28) is capable of being controlled as a function of a temperature detected by the temperature sensor (24) in order to effect the said increase of the respective distance.

3. The battery module (10) according to claim 1 or 2, characterized in thatthe energy storage elements (14) are arranged between two end plates (32, 34), wherein the energy storage elements (14) are capable of being pressurized by the pressure supply device (28) via at least one of the end plates (32, 34).

4. The battery module (10) according to any one of claims 1 to 3, characterized in thatthe coupling element (16) is designed as an electrical connector.

5. The battery module (10) according to any one of claims 1 to 4, characterized in thatthe coupling element (16) is heat resistant.

6. The battery module (10) according to any one of claims 1 to 5, characterized in thatthe coupling element (16) is fire resistant.

7. The battery module (10) according to any one of claims 1 to 6, characterized in thatat least three of the energy storage elements (14) are coupled to each other via the said coupling element (16).

8. An electrical energy storage device (12) for a motor vehicle, comprising at least the battery module (10) according to any one of claims 1 to 7.

9. A method for operating a battery module (10) for an electrical energy storage device (12) of a motor vehicle, wherein the battery module (10) comprises several storage elements (14) and a pressure supply device (28), by which the energy storage elements (14) are pressurized, characterized in thatthe energy storage elements (14) are coupled to each other via a coupling element (16) which is designed as a string (17) capable of being deformed from a normal state (18) to a stretched state (20), wherein the said pressurization of the storage elements (14) is reduced by the pressure supply device (28), whereby a respective distance between two respective adjacent energy storage elements (14) is increased and the coupling element (16) is deformed from the normal state (18) tothe stretched state (20), in which the coupling element (16) is force-loaded by the energy storage elements (14) in order to control the said respective distance.

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