BATTERY ARRANGEMENT WITH AN EXTINGUISHING DEVICE AND MOTOR VEHICLE

Abstract

A battery arrangement with a battery housing in which at least one battery element is arranged. The battery arrangement includes an extinguishing device which has at least one extinguishing unit which is also arranged in the battery housing. The extinguishing unit includes a housing element and an extinguishing agent which is arranged in a cavity in the housing element. The extinguishing unit has a detonation mechanism which is designed to cause a detonation of the housing element and a release of the extinguishing agent in the form of an aerosol when a predetermined fire condition, which results from a fire in the at least one battery element, is present.

Claims

1. A battery arrangement with an extinguishing device, comprising: at least one battery element which is arranged in a battery housing, and the extinguishing device is designed to provide an extinguishing agent in the form of an aerosol for extinguishing the at least one battery element when a predetermined fire condition, which results from a fire in the at least one battery element, is present, wherein the extinguishing device has at least one extinguishing unit which is arranged in the battery housing, wherein the extinguishing unit comprises a housing element and the extinguishing agent, and the housing element has a cavity in which the extinguishing agent is arranged, wherein the extinguishing unit has a detonation mechanism which is designed to cause a detonation of the housing element and a release of the extinguishing agent in the form of the aerosol when the predetermined fire condition is present.

2. The battery arrangement according to claim 1, wherein the extinguishing agent for providing the detonation mechanism has at least one material with a predetermined coefficient of expansion, and is thus designed to cause a pressure increase when the fire condition is present, which is greater by a predetermined limit amount than a predetermined elasticity limit value of the housing element.

3. The battery arrangement according to claim 1, wherein the extinguishing unit for providing the detonation mechanism has a detonation element which as a material comprises an explosive which is designed to detonate when the fire condition is present.

4. The battery arrangement according to claim 3, wherein the battery arrangement has a monitoring system which is designed to monitor at least one state variable relating to the fire condition and in the event that the state variable has a value which represents the fire condition, the monitoring system is designed to control an ignition mechanism of the detonation element with a trigger signal and to cause the detonation of the explosive.

5. The battery arrangement according to claim 1, wherein in a predetermined installation position of the battery arrangement in a motor vehicle, the extinguishing device is arranged in the battery housing in the direction of gravity above the at least one battery element, and thereby causing aerosol particles, which the extinguishing agent has in the aerosol form, to descend in the direction of gravity.

6. The battery arrangement according to claim 1, wherein the extinguishing unit forms a plate which is arranged flat in the battery housing at least on a portion of a housing wall, or the extinguishing device comprises a plurality of extinguishing units arranged at predetermined different positions in the battery housing.

7. The battery arrangement according to claim 1, wherein the extinguishing device comprises a plurality of extinguishing units and a fixing unit for the extinguishing units, wherein the fixing unit is designed to hold the extinguishing units in a predetermined normal state of the battery arrangement in a predetermined position in the battery housing, and the fixing unit is designed to release the extinguishing units from the predetermined position into the battery housing when the fire condition is imminent on the one hand or after detonation of at least one of the extinguishing units when the fire condition is present on the other hand.

8. The battery arrangement according to claim 1, wherein the battery arrangement has a plurality of battery elements and the extinguishing device has a plurality of extinguishing units, wherein one or more dedicated extinguishing units are assigned to each battery element.

9. The battery arrangement according to claim 8, wherein the battery arrangement has a heat protection device with a plurality of heat protection units, wherein one or more dedicated heat protection units are assigned to each battery element, wherein the respective heat protection unit comprises a housing element and a heat protection agent, and the housing element has a cavity in which the heat protection agent is arranged, wherein the respective heat protection unit has a detonation mechanism which is designed to cause a detonation of the housing element and a release of the heat protection agent in the form of an aerosol to the assigned battery element only if the fire condition is present or imminent for another battery element not assigned to the respective heat protection unit.

10. A motor vehicle with a battery arrangement according to claim 1.

11. The battery arrangement according to claim 2, wherein the extinguishing unit for providing the detonation mechanism has a detonation element which as a material comprises an explosive which is designed to detonate when the fire condition is present.

12. The battery arrangement according to claim 2, wherein in a predetermined installation position of the battery arrangement in a motor vehicle, the extinguishing device is arranged in the battery housing in the direction of gravity above the at least one battery element, and thereby causing aerosol particles, which the extinguishing agent has in the aerosol form, to descend in the direction of gravity.

13. The battery arrangement according to claim 3, wherein in a predetermined installation position of the battery arrangement in a motor vehicle, the extinguishing device is arranged in the battery housing in the direction of gravity above the at least one battery element, and thereby causing aerosol particles, which the extinguishing agent has in the aerosol form, to descend in the direction of gravity.

14. The battery arrangement according to claim 4, wherein in a predetermined installation position of the battery arrangement in a motor vehicle, the extinguishing device is arranged in the battery housing in the direction of gravity above the at least one battery element, and thereby causing aerosol particles, which the extinguishing agent has in the aerosol form, to descend in the direction of gravity.

15. The battery arrangement according to claim 2, wherein the extinguishing unit forms a plate which is arranged flat in the battery housing at least on a portion of a housing wall, or the extinguishing device comprises a plurality of extinguishing units arranged at predetermined different positions in the battery housing.

16. The battery arrangement according to claim 3, wherein the extinguishing unit forms a plate which is arranged flat in the battery housing at least on a portion of a housing wall, or the extinguishing device comprises a plurality of extinguishing units arranged at predetermined different positions in the battery housing.

17. The battery arrangement according to claim 4, wherein the extinguishing unit forms a plate which is arranged flat in the battery housing at least on a portion of a housing wall, or the extinguishing device comprises a plurality of extinguishing units arranged at predetermined different positions in the battery housing.

18. The battery arrangement according to claim 5, wherein the extinguishing unit forms a plate which is arranged flat in the battery housing at least on a portion of a housing wall, or the extinguishing device comprises a plurality of extinguishing units arranged at predetermined different positions in the battery housing.

19. The battery arrangement according to claim 2, wherein the extinguishing device comprises a plurality of extinguishing units and a fixing unit for the extinguishing units, wherein the fixing unit is designed to hold the extinguishing units in a predetermined normal state of the battery arrangement in a predetermined position in the battery housing, and the fixing unit is designed to release the extinguishing units from the predetermined position into the battery housing when the fire condition is imminent on the one hand or after detonation of at least one of the extinguishing units when the fire condition is present on the other hand.

20. The battery arrangement according to claim 3, wherein the extinguishing device comprises a plurality of extinguishing units and a fixing unit for the extinguishing units, wherein the fixing unit is designed to hold the extinguishing units in a predetermined normal state of the battery arrangement in a predetermined position in the battery housing, and the fixing unit is designed to release the extinguishing units from the predetermined position into the battery housing when the fire condition is imminent on the one hand or after detonation of at least one of the extinguishing units when the fire condition is present on the other hand.

Description

BRIEF DESCRIPTION OF THE FIGURES

[0040] Exemplary embodiments of the invention are described hereinafter. In the figures:

[0041] FIG. 1 shows a schematic representation of a battery arrangement with an extinguishing device according to a first exemplary embodiment;

[0042] FIG. 2 shows a schematic representation of the battery arrangement with an extinguishing device according to a second exemplary embodiment; and

[0043] FIG. 3 shows a schematic representation of a section of the battery arrangement with an extinguishing device according to a third exemplary embodiment.

DETAILED DESCRIPTION

[0044] The exemplary embodiments explained hereinafter are preferred embodiments of the invention. In the exemplary embodiments, the described components of the embodiments each represent individual features of the invention to be considered independently of one another, which each also further develop the invention independently of one another. Therefore, the disclosure is also intended to comprise combinations of the features of the embodiments other than those represented. Furthermore, the described embodiments can also be supplemented by further ones of the above-described features of the invention.

[0045] In the figures, same reference numerals respectively designate elements that have the same function.

[0046] FIG. 1 shows a schematic representation of a battery arrangement 1 from a side view in a sectional representation. The battery arrangement 1 can be used, for example, as an electrical energy store for a motor vehicle. The motor vehicle can thus be a battery-electric vehicle, for example an electric vehicle or hybrid vehicle. In FIG. 1, the battery arrangement is represented in a predetermined installation position L, as it can be installed in the motor vehicle, for example.

[0047] The battery arrangement 1 has a drive battery 10 for operating the motor vehicle. By means of the drive battery 10, for example, electrical energy can be provided to an electric drive of the motor vehicle, such as an electric machine, and/or to an on-board network of the motor vehicle. The drive battery 10 is, for example, an accumulator or a secondary battery. In order to operate the motor vehicle, the drive battery 10 can provide electrical energy in the form of an electrical current and/or an electrical voltage. For this purpose, the drive battery 10 comprises at least one battery element 11. The battery element 11 can be a battery cell, i.e. a galvanic cell, for example. An electrochemistry of the battery cell can be based on lithium-ion technology, for example. The number of the battery elements 11 can be selected from a desired amount of energy to be supplied by the drive battery 10. In FIG. 1, five battery elements 11 are represented as an example. Of course, more or fewer battery elements 11 can also be used to form the drive battery 10.

[0048] To form the drive battery, the battery elements 11 can be electrically connected to one another in a suitable manner. To hold the battery elements 11, the drive battery 10 comprises a battery housing 12. In the battery housing 12, the battery elements 11 are arranged stacked next to one another in a predetermined stacking direction R, i.e. adjacent to one another. The battery elements 11 form a stacked assembly 13. In FIG. 1, the housing 12 and the battery elements 11 have a substantially rectangular cross section. The battery elements 11 can thus be present as so-called prismatic cells. In the installation position L from the side view, four housing walls of the housing 12 are represented in FIG. 1. The housing walls are a lid 12a, which is represented at the top in the installation position L according to FIG. 1, a base 12b, which is shown at the bottom opposite the lid 12a in the installation position L, and two opposite side walls 12c and 12d, which are shown on the right and left in the installation position L and support the lid 12a and the base 12b against each other.

[0049] Since the drive battery 10 can be designed as an accumulator, it is clear here that the drive battery 10 can also be supplied with electrical energy itself for recharging, for example by means of a vehicle-external charging station or by means of the electric drive through so-called recuperation. This means that the drive battery 10 or the battery elements 11 can be operated both in charging mode and in discharging mode. When the battery elements 11 are operated as intended, the respective battery element 11 may heat up, for example due to electrochemical reactions taking place in an active material that can form the electrochemistry. Under certain prerequisites or conditions, a respective battery element 11 may even overheat. A prerequisite for this can be, for example, a short circuit in one of the battery elements 11 or a mechanical defect. When overheating, it can happen that the respective battery element 11 thermally runs away. This means that the respective battery element 11 heats up until it reaches a predefined reaction temperature limit value. This can depend, for example, on a battery technology of the battery element 11 used. For example, with the aforementioned lithium-ion technology, the reaction temperature limit value may be about 84° C. If the battery element 11 reaches this reaction temperature limit value, an unstoppable or reversible electrochemical reaction can take place in the active material. This reaction quickly releases a lot of energy in the form of heat. For example, a battery element based on lithium-ion technology can release about 60 percent of its stored amount of energy in the form of thermal energy within two to three seconds when it reaches the reaction temperature limit value. As a result, the temperature of the battery element 11 can increase to up to 1,200° C., for example, depending on the electrochemistry. As a result, the battery element 11 catches fire. The condition that the battery element 11 has when the fire is present is also referred to as fire condition Z below.

[0050] The battery element 11 which is burning or with thermal runaway can release the thermal energy to the remaining battery elements 11. A so-called thermal propagation or chain reaction can occur. This means that the remaining battery elements 11 can also overheat when they are subjected to the thermal energy. In order to prevent the thermal propagation, the burning battery element 11 can be deprived of the heat energy. For this purpose, the battery arrangement 1, as shown in FIG. 1, comprises an extinguishing device 20. The extinguishing device 20 is designed to provide an extinguishing agent in the form of an aerosol to extinguish the at least one battery element 11 when the fire condition Z is present. That is, the extinguishing agent can form or have aerosol particles that can be used to extinguish the battery fire. Aerosol thus means a very fine distribution of suspended solid or liquid particles or aerosol particles in a gaseous surrounding medium, such as air.

[0051] To provide the aerosol, the extinguishing device 20 comprises an extinguishing unit 21. FIG. 1 shows a first possible configuration of how the extinguishing unit 21 can be realized. In FIG. 1, the extinguishing unit 21 is designed, for example, in the form of a plate and, according to the present exemplary embodiment, is arranged along the stacking direction R on the stacked assembly 13 in the region of the lid 12a. In this case, the extinguishing unit 21 can completely or partially cover or overlap a surface of the stacked assembly 13 that extends along the stacking direction R. How the extinguishing unit 21 can be designed to provide the aerosols can be described in more detail with reference to FIG. 2.

[0052] FIG. 2 shows an alternative second possible configuration of the extinguishing device 20 according to FIG. 1. The battery arrangement 1 according to FIG. 1 is represented in a plan view or bird's eye view, i.e., for example, from the direction of the lid 12a, in a sectional representation. The housing 12, on the other hand, has a rectangular cross section, wherein only the four side walls of the housing 12 are represented, namely the side walls 12c and 12d described above and the side walls 12e and 12f. In FIG. 2, six battery elements 11 are arranged in the battery housing as an example. The battery elements 11 are arranged in several rows and columns in the plane spanned by the housing 12. The stacked assembly 13 of the battery elements 11 can thus be referred to as a stack matrix.

[0053] According to FIG. 2, the extinguishing device 20 comprises several or a plurality of extinguishing units 21. The extinguishing units 21 each have a rectangular cross section and are arranged in the housing 12 in a star or cross shape. That is, one of the extinguishing units 21 is arranged centrally in the battery housing 12 in plan view. Starting from the central extinguishing unit 21, the remaining extinguishing units 21 are each attached in the corners of the battery housing 12. As indicated in FIG. 2 by the dashed drawing of the battery elements 11, the extinguishing units 21 are again arranged above the battery elements 11 in the installation position L, i.e. in the region of the lid 12a. This results in the advantage that an effective direction of gravity can support the distribution of the extinguishing agent in the battery housing 12. To hold the extinguishing units 21, the extinguishing units 21 according to FIGS. 1 and 2 can be fastened to the housing lid 12a, for example. Alternatively, the extinguishing units can rest on the stacked assembly and/or be fastened to the battery elements 11. For fastening, the extinguishing units 21 can be glued or welded on, for example. A further fastening option can be explained in more detail later with reference to FIG. 3.

[0054] As shown in FIG. 2, the extinguishing units 21 have a substantially square cross section. A dimension of the extinguishing units 21 can be adapted to a dimension of the battery elements 11, for example. For example, a diameter of the respective extinguishing unit 21 can be between 1 and 10 centimeters.

[0055] To provide the aerosol extinguishing agent, the extinguishing unit 21, as shown in FIG. 2, has a housing element 21a. The housing element 21a has a cavity. So it's hollow inside. Thereby, the housing element 21a forms an envelope or container. The extinguishing agent 21b is arranged or introduced in the cavity. For example, the extinguishing agent can be a liquid such as water. In order to release the extinguishing agent 21b in the form of the aerosol, the extinguishing unit 21 has a detonation mechanism 21c. If the fire condition Z is present, this can cause a detonation of the housing element 21a. A detonation pulse of the detonation can cause the extinguishing agent 21b to be released and atomized to form aerosol particles, which form the aerosol with ambient air in the battery housing 12. The strength of the detonation pulse can determine a size, for example a diameter, of the aerosol particles. The detonation mechanism is selected, for example, so that the detonation pulse is at least locally limited to the battery housing 12 or the battery element 11 to be extinguished. It can thus be ensured that the surrounding components around the battery arrangement 1 of the motor vehicle or the remaining battery elements 11 are not impaired by the detonation.

[0056] In order to achieve the most effective possible atomization of the extinguishing agent 21b, the housing element 21a can be rigid, i.e. non-deformable, for example. That is, the housing element 21a can have a rigid or stiff material. In particular, when shaping the housing, the material can provide a low density. This ensures that no fragmentation occurs during the detonation. The material can also be temperature resistant for the fire condition Z. It can thus be ensured that the housing element 21a does not melt before the aerosol has been released. A duromer (resin) or a fiber-reinforced plastic or a polymer foam, for example, are suitable as the material for the housing element 21a. A wall thickness of the housing element 21a can be overall adapted to a dimension of the extinguishing unit 21, for example. But overall, the wall thickness can be between 0.1 and 1 centimeter, for example.

[0057] Various possible configurations are conceivable for the detonation mechanism 21c. For example, the detonation mechanism can be provided in that the extinguishing agent 21b has a predetermined coefficient of expansion, which can cause an increase in pressure in the housing element 21a when the fire condition Z is present. This increase in pressure is greater by a predetermined limit amount than a predetermined elasticity limit value of the housing element 21a can withstand. This means that the pressure can be so high that the housing breaks due to the mechanical load and detonates, for example.

[0058] A further possible configuration consists, for example, in equipping the extinguishing unit 21 with a detonation element (not represented in the figures). The detonation element can comprise an explosive or a blasting agent as a material. It is designed to detonate when the fire condition is present. The explosive can, for example, be designed to be self-igniting. That is, an energetic activation of the explosive can be provided by a trigger temperature value comprised by the fire condition. Alternatively, the detonation element can be designed for remote ignition. For this purpose, the battery arrangement 1 can have a monitoring system, for example, which can be used to monitor whether the fire condition Z is present for one of the battery elements 11. If the fire condition Z is detected, the monitoring system can provide a trigger signal to an ignition mechanism of the detonation element, thereby causing the explosive to detonate. For example, the ignition mechanism can comprise a pyrotechnic igniter.

[0059] FIG. 3 shows an alternative third possible configuration of the extinguishing device 20. In FIG. 3, a section of the battery arrangement 1 according to FIG. 2 is represented. According to the third possible configuration, the extinguishing device 20 again has a plurality of extinguishing units 21, for example six in the present case. In contrast to the configuration according to FIG. 2, however, the extinguishing units 21 have a round cross section. That is, the extinguishing units 21 can be designed in a spherical shape, for example.

[0060] For fastening or fixing the extinguishing units 21, the extinguishing device 20 comprises a fixing unit 22. According to the exemplary embodiment in FIG. 3, the fixing unit 22 is designed, for example, as a net. That is, a fixing body of the fixing unit 22 has a net-like structure. With the fixing unit 22, the extinguishing units 21 can be held at a desired position in the battery housing 12 in a normal state of the battery arrangement 1. In the present case, the extinguishing units 21 are held by the fixing unit 22, for example above the battery elements 11 in the region of the lid 12a. The fixing unit 22 is now formed, for example, to release the extinguishing units 21 from the predetermined position into the battery housing 12 when the fire condition Z is imminent. For this purpose, the fixing unit can be formed from a thermosensitive material, for example. This means that the material can have a melting point that is in a predetermined temperature value range that is not comprised by the fire condition Z. In this case, the temperature value range can be selected, for example, so that the temperature value range comprised by the fire condition is directly adjacent to it.

[0061] For example, the melting temperature, i.e. the melting point of the fixing unit 22, can be at the reaction temperature limit value which characterizes the start of the thermal runaway of the respective battery element 11. The extinguishing units 21 can thus be released into the battery housing 12 shortly before the fire condition Z occurs and can thus be provided directly to the battery elements 11. As shown in FIG. 3, a diameter D of the extinguishing units can be selected so that it is smaller than a distance a between two adjacent battery elements 11 in the stacked assembly 13. Thus, the extinguishing units 21 can, for example, reach an intermediate space between the two adjacent battery elements 11 during release. As a result, thermal propagation, i.e. overheating, of the adjacent battery elements to a battery element 11 having the heating condition Z can be prevented even more effectively.

[0062] Alternatively to the thermosensitive material of the fixing unit 22, it can be provided that the fixing unit 22 releases the extinguishing units 21 after detonation of at least one of the extinguishing units 21 on the battery housing 12. That is, a detonation pulse of the extinguishing unit 21 can destroy a structure of the fixing unit 22. For this purpose, the fixing unit can, for example, have a material whose elasticity limit value is lower than a force that the detonation pulse exerts on the fixing body of the fixing unit 22.

[0063] Overall, the examples show how an aerosol extinguishing unit for a drive battery 10 can be implemented.