FIRE PREVENTION OR FIRE EXTINGUISHING IN AN ELECTROCHEMICAL ENERGY STORAGE SYSTEM

Abstract

A device for preventing or extinguishing a fire in an electrochemical energy storage system comprising storage cells arranged in a storage housing, wherein the energy storage system is connected to a discharge unit for discharging energy from the energy storage system, the discharge unit comprising: at least one anchor, and a drive assembly for driving the at least one anchor to the ground, the anchor being electrically connected to the energy storage system, such when the anchor is driven to the ground, the energy storage system is grounded.

Claims

1. A device for preventing or extinguishing a fire in an electrochemical energy storage system comprising storage cells arranged in a storage housing, wherein the energy storage system is connected to a discharge unit for discharging energy from the energy storage system, the discharge unit comprising: at least one anchor, and a drive assembly for driving the at least one anchor to the ground, the anchor being electrically connected to the energy storage system, such when the anchor is driven to the ground, the energy storage system is grounded.

2. The device according to claim 1, wherein the drive assembly comprises a pyrotechnical drive cartridge.

3. The device according to claim 1, wherein the drive assembly is connected to a vehicle control system and adapted to drive the anchor to the ground when a crash signal is received at the drive assembly.

4. The device according to claim 3, wherein the crash signal is a delayed air-bag signal.

5. The device according to claim 1, wherein the drive assembly is adapted to drive the anchor into the ground.

6. The device according to claim 1, further including a composition of expandable volume, containing an extinguishing agent for preventing or extinguishing a fire, is disposed with limited volume in one or a plurality of hollow spaces in or on the storage housing, wherein expansion of the volume of the composition can be activated by sensors.

7. The device according to claim 6, wherein expandable compositions are assigned to storage modules of the energy storage system, said storage modules comprising respective pluralities of storage cells.

8. The device according to claim 6, wherein the expandable composition is disposed inside the housing of a respective storage module.

9. The device according to claim 6, wherein at least a part of the discharged energy of the discharge unit is used for expanding the composition.

10. The device according to claim 6, wherein the expandable composition is disposed in one or more containers.

11. The device according to claim 6, wherein the expandable composition is provided as a coating.

12. The device according to claim 6, wherein the expandable compositions is provided as a shaped body.

13. The device according to claim 6, wherein the expandable composition is an aerosol-forming composition.

14. The device according to claim 6, wherein the extinguishing agent for preventing or extinguishing a fire includes a chemical compound which reacts with radicals released by the fire to form at least one stable compound.

15. The device according to claim 6, wherein the expandable composition includes at least one alkali metal compound, in particular a potassium compound.

16. The device according to claim 6, wherein the expandable composition includes potassium nitrate.

17. The device according to claim 6, wherein the extinguishing agent for preventing or extinguishing a fire includes a mineral or vitreous granulate.

18. The device according to claim 17, wherein the granulate has a grain size of less than 0.5 mm.

19. The device according to claim 6, wherein the expandable composition includes a dry propellant.

20. The device according to claim 19, wherein the propellant forms nitrogen when it expands.

21. The device according to claim 6, wherein the expanded composition includes a gas or gas mixture held under pressure in a container.

22. An electrochemical energy storage system provided with the device according to claim 1.

23. The storage system according to claim 22, comprising a sensor unit being sensitive to an excessive acceleration or braking force acting on the electrochemical storage system, or sensitive to any damage occurring in or caused to the electrochemical storage system.

24. The device according to claim 1, comprising an expandable component, comprising one or more of the following components: at least one substance preventing an uncontrolled chemical reaction in a respective storage cell; at least one substance extinguishing a fire in the energy storage system; at least one substance forming a barrier between the anode and the cathode of a respective storage cell; at least one aerosol-forming substance; at least one dry propellant which can be converted by activation to a gaseous form; at least one gas or gas mixture which is held under pressure.

25. The device according to claim 24, wherein the fire-extinguishing substance includes at least one potassium compound which decomposes during combustion to release potassium, which reacts with free radicals produced during combustion to form stable potassium hydroxide, and/or includes a mineral or vitreous granulate.

26. The device according to claim 24 characterised by an arrangement which activates expansion of the composition two or more times.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0033] FIG. 1 is a schematic view of an electrochemical energy storage system;

[0034] FIG. 2 is a schematic view of a vehicle including a device for preventing or extinguishing a fire;

[0035] FIG. 3 is a schematic view of a device for preventing fire; and

[0036] FIGS. 4a and 4b show an example of a drive assembly.

DETAILED DESCRIPTION OF THE DRAWINGS

[0037] The attached FIG. 1 shows an electrochemical energy storage system 1, which can be a battery for a vehicle, in particular for a motor vehicle. However, it may also be a battery which is deployed in a stationary manner. Storage cells 3 are arranged in a storage housing 2 of energy storage system 1. The cells may be lithium-ion cells, for example. Inside the housing, a container 4 is disposed in which a composition of expandable volume, preferably in a compact form, is held in readiness. This composition may be an extinguishing agent for preventing or extinguishing a fire. It may be a chemical substance which is used to prevent or extinguish the fire. The extinguishing agent for preventing or extinguishing the fire is distributed inside storage housing 2 by means of a propellant. However, it is also possible to provide a container 4 containing the expandable composition for each storage cell 3, or for each pack consisting of a plurality of storage cells 3. Container 4 may also be disposed on the outside of storage housing 2.

[0038] As an extinguishing agent, the expandable composition inside housing 4 may also include a mineral or vitreous granulate. Not only the mineral or vitreous granulate, but also the chemical substance used to prevent or extinguish the fire may be used for the extinguishing agent.

[0039] Expansion of the volume of the composition provided in container 4 can be activated by sensors. One or more sensors may be provided for that purpose. For example, one or more temperature sensors 5 and/or one or more acceleration sensors 6 may be provided. In this way, it is possible to detect any excessive temperature in storage housing 2. It is also possible to detect any excessive braking or acceleration force, in particular any damage caused to energy storage system 1 or to storage cells 3. Sensors 5, 6 are connected to an analyser/controller 7, which can be an electronic computer device, for example the on-board computer in a vehicle. In analyser/controller 7, the signals from the sensors are analysed with regard to the prevention or extinguishing of a fire in or on energy storage system 1, and the respective control signals for initiating expansion of the volume of the composition kept in container 4 are supplied accordingly.

[0040] FIG. 2 illustrates a vehicle 10 comprising an energy storage system 1 mounted in a floor area 12 of the vehicle. In this embodiment, the energy storage system 1 is connected to a discharge unit 14 via a cable 16. The discharge unit is adapted to discharge energy from the energy storage system 1 and will be described in more detail with reference to FIGS. 3 and 4.

[0041] As shown in FIG. 3, the discharge unit 14 comprises one anchor 16, 18 and a drive assembly 20 (which will be described in further detail with FIG. 4). The drive assembly 20 is adapted to drive the anchor 18 towards the ground and thus, out of the bottom 12 of the vehicle 10. The Anchor 18 is connected to the wire 16 and the wire 16 has a length, such that anchor 18 can reach the ground and preferably that the vehicle 10 can move after the anchor 18 has engaged the ground. In this embodiment, the anchor 18 is adapted to be moved into the ground and therefore it comprises a sharp edge 22, which might be formed based on ballistic design rules. Anchor 18 is made out of metal, such that it can conduct electrical energy. Wire 16 is designed with a relatively large diameter so that as much current as possible may flow from the energy storage device 1 through cable 16 into anchor 18 and from anchor 18 to the ground. Due to the discharge of the energy storage device 1, the tendency for a fire or explosion is lowered.

[0042] The drive assembly 20 is connected to the analyzer/controller 7 via a respective signal line 24. The analyzer/controller 7 may be connected to the vehicle control unit. Alternatively, the drive assembly 20 is directly connected to the vehicle control unit. The drive assembly 20 receives a signal from analyzer/controller 7 via signal line 24 to drive the anchor 18 to the ground.

[0043] In this embodiment, the drive assembly 20 is a pyrotechnical drive, shown in FIGS. 4a and 4b. While FIG. 4a is a side view of the drive assembly, FIG. 4b is a cut along line A-A according to FIG. 4a. Drive assembly 20 has a pressure pipe 30 having a pipe access 32, in which a piston 34, which can be driven by a drive gas, can be moved along a linear guideway 35. A piston rod 36 extends along the linear guideway 3 inside the pressure pipe 30 and is securely connected to the piston 34. The piston 34 and piston rod 36 may be two parts, or formed as one piece. A rod portion 37 of piston rod 36 projects beyond a first pressure pipe end, in particular at first guideway end 38. A connection point 39 at which the piston rod can be connected to the anchor 18, or a mounting assembly of the anchor 18 is provided on said rod portion 36. As shown in FIGS. 4a and 4b, connection point 39 may be in the form of a log for receiving a part of the anchor 18. However, preferably, the connection point 39 is only detachably mounted to anchor 18, so that anchor 18 can be released from rod 39. To release anchor 18 from rod 39, anchor 18 may be connected to connection point 39 by means of a breakable element, as e.g. a plastic element with a breakpoint.

[0044] A second connection point 40 is provided on the pressure pipe 30 at the second guideway end 41. This second connection point 40 is designed for supporting the drive assembly 20 at the vehicle body. As shown in the FIGS. 4a and 4b, the second connection point 40 may likewise be in the form of a log, which can force-lockingly receive a support member of the vehicle body.

[0045] The second connection point 20 can be securely connected by a fitting part 42 to pressure pipe 30. Connection point 39 and 40 are arranged in such a way that they are aligned with the linear extension of guideway 35 of pressure pipe 30. However, the second connection point 20 may also be attached in the intermediate vicinity of the angled pressure pipe portion 43. It is preferably attached by welding, in particular by but welding, to the welding portion 44 in the region of the angled pressure pipe portion 43.

[0046] A drive gas is supplied by a gas source 45 to drive piston 34 along linear guideway 3. Piston 34 contacts the inner surface of pressure pipe 30 tightly, by means of a sealing ring 46, for example, by means of an O-ring. Gas source 45 is located in a pressure pipe portion 43, which is angled at an angle to the linear guideway 3 of pressure pipe 30; the interior of angled pressure pipe portion 43 continuous into the interior of linear guideway 3. The drive gas produced by gas source 8 acts on the rear side of piston 34 and moves the latter along guideway 3 in pressure pipe 30.

[0047] Piston 34 and piston rod 36 are preferably made of metal or any conducting material. Alternatively it may be made of a fiber/plastic composing material, in particular of glass, fiber/plastic composing material, in particular of glass, fiber/plastic composing material. There might be an additional wire for providing a conducing connection when needed. Pressure pipe 30 is preferably made of stainless steel.

[0048] Gas source 45 is preferably embodied as an electrically ignitable gas generator, in particular as a pyrotechnical gas generator. The gas generator is inserted tightly into the end of the angled pressure pipe portion 43. At its free end, there is an electrical plug connection part 47, to which signal line 24 (see FIG. 3) might be connected. By means of igniting the gas source 45, gas is introduced into the pressure pipe 30 at portion 48, such that connector 39 is moved downwards and drives anchor 18 to the ground.

[0049] Many changes and modifications in the above-described embodiment of the invention can, of course, be carried out without departing from the scope thereof. Accordingly, that scope is intended to be limited only by the scope of the appended claims.