Battery storage device with safety device and method for operating the safety device

Abstract

1. A battery storage device (10) comprising a storage housing (12) and at least one battery cell disposed in an interior space (33) of the storage housing (12) and including a sulfur dioxide-based electrolyte, the battery storage device having a safety device comprising a supply device (32) including a foaming additive (16) and configured to generate a foam (35) from the foaming additive (16) to neutralize the electrolyte and to release the foam (35) into the interior space (33) of the storage housing (12).

Description

[Technical field]

[0001] The present invention relates to a battery storage device with a safety device and a method for activating the safety device. [Background technology]

[0002] Electrochemical cells are of great importance in many technological fields. For example, they are often used in mobile applications such as laptops, electric bicycles and mobile phones. One advantage of electrochemical cells is that they can be connected in series or parallel to form batteries with higher energy. Such batteries can be combined with so-called battery storage devices (battery storage systems) and are particularly suitable for high-voltage applications. Battery storage devices, for example, enable the electric drive of cars and can be used as stationary energy storage devices.

[0003] In the following, the term "electrochemical cell" is used synonymously with all terms commonly used in the art for rechargeable galvanic elements, such as cell, battery, battery cell, accumulator, battery accumulator, secondary battery, etc.

[0004] An electrochemical cell can provide electrons to an external circuit during a discharging process, and conversely, an electrochemical cell can be charged using an external circuit during a charging process by providing electrons.

[0005] An electrochemical cell has at least two different electrodes, a positive electrode (cathode) and a negative electrode (anode). Both electrodes are in contact with a separator, which is an electrical insulator. For example, porous polyolefin separators impregnated with a liquid electrolyte composition are used in the art. The separator spatially separates the two electrodes from each other and ionically connects the two electrodes to each other.

[0006] The most commonly used electrochemical cell is the lithium-ion battery, also known as lithium ion battery. Prior art lithium-ion batteries usually have a composite anode, which very often consists of a carbon-based anode active material, typically graphitic carbon, which is usually coated with an electrode binder on a metallic copper support foil. In principle, a composite cathode consists of a cathode active material, e.g. a layered oxide, a binder, a conductive additive, which are applied to, e.g., a rolled aluminum current collector foil. The layered oxide is often LiCoO 2 Or LiNi 1 / 3 Mn 1 / 3 Co 1 / 3 O 2 It consists of:

[0007] Lithium-ion batteries generally have a liquid electrolyte composition that ensures charge balancing between the cathode and anode during the charge and discharge process. The current flow required for this is achieved by ionic transport of a conductive salt in the electrolyte composition. In lithium-ion batteries, the conductive salt is a lithium conductive salt (e.g., LiPF 6 , LiBF 4 ) and the dissociated lithium ions move in the electric field between the electrodes.

[0008] In addition to the lithium conductive salt, the electrolyte composition contains a solvent that allows dissociation of the conductive salt and sufficient mobility of the lithium ions. Liquid organic solvents consisting of linear and cyclic dialkyl carbonates are known from the prior art. As a rule, mixtures of ethylene carbonate (EC), dimethyl carbonate (DMC), diethyl carbonate (DEC), propylene carbonate (PC) and ethyl methyl carbonate (EMC) are used. Each of the solvents listed here has a certain stability range in which it functions stably at a given cell voltage. This range is also called the voltage window. An electrochemical cell can operate stably within this voltage window. Approaching the limits of the voltage window, electrochemical oxidation or reduction of the components of the electrolyte composition occurs. Therefore, efforts are being made to use electrolytes that are more stable for different cell voltages.

[0009] Thus, lithium ion batteries using inorganic electrolytes with sulfur dioxide as a solvent represent a further development of lithium ion batteries using organic electrolytes. Various approaches for stable electrolyte compositions based on sulfur dioxide are known in the art.

[0010] EP1201004B1 discloses a secondary battery with an electrolyte based on sulfur dioxide. The sulfur dioxide is not added as an additive, but is the main component of the electrolyte composition as a solvent for the conductive salt. It is therefore necessary to ensure, at least in part, the mobility of the lithium ions of the conductive salt, which affects the ionic transport between the electrodes. In the proposed cell, lithium tetrachloroaluminate (LiAlCl 4 ) as a lithium-containing conductive salt, transition metal oxides, particularly lithium cobalt oxide (LiCoO 2 ) in combination with cathode active materials from intercalation compounds such as . The addition of salt additives, such as alkali halides such as lithium fluoride, sodium chloride, and lithium chloride, to the sulfur dioxide-containing electrolyte composition has resulted in functioning, rechargeable cells.

[0011] EP 2 534 719 B1 describes a rechargeable lithium battery cell using a sulfur dioxide-based electrolyte in combination with lithium iron phosphate (LFP) as the cathode active material. Lithium tetrachloroaluminate was used as the preferred conductive salt in the electrolyte composition. Tests of cells based on these components demonstrated high electrochemical resistance of the cells.

[0012] WO2015 / 043573A2 describes an electrochemical secondary battery cell comprising a housing, a cathode, an anode and an electrolyte comprising sulfur dioxide and a conductive salt, at least one of the electrodes comprising a binder selected from the group consisting of a polymeric binder A, the binder A being a polymer consisting of monomeric structural units of a conjugated carboxylic acid or an alkali metal, alkaline earth metal or ammonium salt of said conjugated carboxylic acid or a combination thereof, and a binder B, the binder B being a polymer based on monomeric structural units of styrene and butadiene or a mixture of binders A and B.

[0013] WO2021 / 019042A1 describes a secondary battery cell with an active metal, a layered oxide as a cathode active material, and an electrolyte containing sulfur dioxide. Due to the low solubility of many common lithium conductive salts in sulfur dioxide, + Z(OR) 4 - A conductive salt of the formula Li was used in the battery, where M represents a metal selected from the group consisting of alkali metals, alkaline earth metals and metals of Group 12 of the Periodic Table, and R is a hydrocarbon residue. Each alkoxy group -OR is bonded to a central atom, which may be aluminum or boron. In a preferred embodiment, the cell is a conductive salt of the formula Li + [Al(OC(CF 3 ) 3 ) 4 -

[0011] . Cells made from the described components exhibit stable electrochemical performance in experimental studies. Moreover, the conductive salts, especially the perfluorinated anions, exhibit surprising hydrolytic stability. Furthermore, the electrolytes have been shown to be stable against oxidation up to an upper potential limit of 5.0 V. Also, cells using the disclosed electrolytes have been shown to be capable of being discharged or charged at temperatures as low as -41°C.

[0014] Furthermore, the unpublished German patent application No. 102021118811.3 discloses a liquid electrolyte composition based on sulfur dioxide for electrochemical cells. The electrolyte composition comprises the following components: A) sulfur dioxide; B) at least one salt, which comprises an anionic complex with at least one bidentate ligand. The counterion of the anionic complex is a metal cation selected from the group consisting of alkali metals, alkaline earth metals and metals of group 12 of the periodic table. The central ion Z of the complex is selected from the group consisting of aluminum and boron. The bidentate ligand forms a ring with the central ion Z and two oxygen atoms bonded to the central ion Z and to the bridging residues, whereby the ring comprises a consecutive sequence of 2 to 5 carbon atoms. Furthermore, an electrochemical cell, in particular a lithium-ion battery, with the above electrolyte composition has been proposed.

[0015] In addition, cells with sulfur dioxide based electrolytes are known from EP 3703161 A1, EP 2227838 B1, EP 2742551 B1, EP 3771011 A2, WO 2005 / 031908 A2, and WO 2014 / 121803 A1, which are incorporated herein by reference. [Prior art documents] [Patent documents]

[0016] [Patent Document 1] EP2534719B1 [Patent Document 2] WO2015 / 043573A2 [Patent Document 3] WO2021 / 019042A1 [Patent Document 4] German Patent Application No. 102021118811.3 [Patent Document 5] EP3703161A1 [Patent Document 6] EP2227838B1 [Patent Document 7] EP2742551B1 [Patent Document 8] EP3771011A2 [Patent Document 9] WO2005 / 031908A2 [Patent Document 10] WO2014 / 121803A1 Summary of the Invention [Problem to be solved by the invention]

[0017] When a battery cell, particularly a lithium-ion battery with a sulfur dioxide-based electrolyte composition, experiences a mechanical, electrical, or thermal defect, the cell can open and electrolyte components, particularly gaseous electrolyte components such as sulfur dioxide, can be released from the cell.

[0018] The invention is based on the problem of preventing leakage (leaking) of electrolyte into the environment in the event that a cell using an electrolyte based on sulfur dioxide is damaged in such a way. [Means for solving the problem]

[0019] According to the invention, this problem is solved by a battery storage device comprising a safety device as claimed in claim 1 and at least one battery cell.

[0020] Advantageous embodiments of the battery storage device according to the invention are shown in the dependent claims and the figures, which can be combined with one another in any desired manner.

[0021] According to the invention, this problem is solved by a battery storage device comprising a storage housing and at least one battery cell arranged in the interior space of the storage housing and containing an electrolyte based on sulfur dioxide, the battery storage device having a safety device with a supply device, the supply device containing a foaming additive and designed to generate foam from the foaming additive to neutralize the electrolyte and to release the foam in the interior space of the storage housing.

[0022] The basic idea of ​​the invention is that in case of mechanical, thermal or electrical failure of the cell, the proposed battery storage device is equipped with a safety device that neutralizes or binds the sulfur dioxide based electrolyte leaking from the cell by releasing a foam.

[0023] This provides the technical advantage that any leaked electrolyte can be quickly and safely absorbed by the foam's large surface area and easily neutralized or bound.

[0024] At this point, neutralization of the electrolyte is understood to mean chemical neutralization which converts the electrolyte components, in particular sulfur dioxide, into chemically more stable and less toxic compounds.

[0025] A further advantage is that the neutralization of the electrolyte already takes place in the internal space of the storage housing. In particular, the storage housing is designed to be liquid-tight, so that the foam, electrolyte and other components remain in the battery storage system after neutralization. The storage housing therefore provides a defined, spatially limited reaction chamber in which the chemical neutralization can be carried out under controlled conditions. Advantageously, once the neutralization is complete, the battery storage device unit can be disposed of separately or put into a recycling process.

[0026] The technical advantage of using foams is that the released foam can fix the leaked electrolyte. The individual components of the electrolyte can adhere adsorptively to the foam cell skin and be bound to the foam. Alternatively, the electrolyte components can be stored in the foam bubbles. In both cases, the leaked electrolyte is restricted in its movement and is quickly fixed in the inner space of the storage housing. Furthermore, the electrolyte thus fixed can be neutralized by the chemical properties of the foam itself. More specifically, the electrolyte can undergo a chemical reaction with the components of the foam, neutralizing the electrolyte and converting it into a more chemically stable compound. The foam simultaneously fixes the electrolyte, resulting in a particularly complete and efficient neutralization of the electrolyte.

[0027] The proposed battery storage device is preferably placed in a vehicle and used to power the vehicle. Of course, it is also possible to place several battery storage devices in such a vehicle. The battery storage device according to the invention is not limited to mobile applications such as vehicles, but can also be used for stationary operation. For example, the battery storage device according to the invention can be used to store energy from solar systems or wind power plants.

[0028] For the purposes of the present invention, a battery storage device refers to a storage housing in which at least one battery cell, preferably a plurality of battery cells, are arranged. The battery cells can be interconnected within the storage housing to provide higher levels of energy. By battery cell is meant an electrochemical cell with an electrolyte based on sulfur dioxide. Preferably, the battery cell is a lithium-ion battery.

[0029] The present invention is not further limited with respect to the sulfur dioxide-based electrolyte composition, and therefore any sulfur dioxide-based electrolyte composition commonly used in the prior art can be used.

[0030] In particular, a sulfur dioxide-based electrolyte is understood to mean a liquid electrolyte composition that contains sulfur dioxide as a component. The sulfur dioxide can be present in the electrolyte composition in liquid, gaseous or complexed form.

[0031] Suitable examples of such electrolyte compositions are known from EP 1201004 B1, EP 2534719 B1, WO 2015 / 043573 A2, WO 2021 / 019042 A1, EP 3703161 A1, EP 2227838 B1, EP 2742551 B1, EP 3771011 A2, WO 2005 / 031908 A2 and WO 2014 / 121803 A1, and from the not yet published German patent application No. 102021118811.3, which is incorporated herein by reference.

[0032] In an advantageous embodiment of the invention, the foaming additive is present in an aqueous solution.

[0033] The foaming additive comprises at least one foaming agent. The present invention is not further limited with respect to the foaming agent. Generally, all foaming agents commonly used in the prior art can be used in the foaming additive.

[0034] Foaming agents that can be used include protein foaming agents, fluoroprotein foaming agents, aqueous film-forming protein foaming agents, multigrade foaming agents, and alcohol-resistant foaming agents.

[0035] Preferably, the foaming additive is selected from the group consisting of ionic surfactants, saponins and proteins, and combinations thereof.

[0036] Suitable examples of foaming agents include alkylbenzenesulfonates, fatty alcohol polyglycol ether sulfates, alkanesulfonates, alkyl ether carboxylates, betaines, fatty acid sulfoalkylamides, fatty acid sulfoalkyl esters, sodium lauryl sulfoacetate, sodium lauroyl sarcosinate, sodium lauroyl ether sulfate, sodium dodecyl sulfate, coconut fatty acid monoglyceride sulfate, sodium docusate, sodium lauroyl sulfoacetate, sodium lauroyl sarcosinate, and sodium dodecyl sulfate, and combinations thereof.

[0037] The proposed blowing agents have the technical advantages of being cheap, readily available and well miscible with water.

[0038] The foaming additive may comprise 0.1 to 6 mass %, preferably 4 to 6 mass %, particularly preferably 5 to 6 mass %, based on the total mass of the foaming additive.

[0039] The foaming additive further comprises a base. The present invention is not further limited with respect to the base. In general, all bases commonly used in the prior art can be used in the foaming additive.

[0040] For example, the base can be porous natural lime.

[0041] Preferably, the base is selected from the group consisting of carbonates, bicarbonates, oxides, hydroxides and combinations thereof.

[0042] In particular, metal carbonates are used as carbonates, preferably alkali metal carbonates and alkaline earth metal carbonates. Suitable examples of carbonates are barium carbonate, calcium carbonate, magnesium carbonate, potassium carbonate, sodium carbonate and zinc carbonate, and combinations thereof.

[0043] In particular, metal bicarbonates are used as bicarbonates, preferably alkali metal and alkaline earth metal bicarbonates. Suitable examples of bicarbonates include calcium bicarbonate, magnesium bicarbonate, barium bicarbonate, strontium bicarbonate, sodium bicarbonate and potassium bicarbonate, and combinations thereof.

[0044] In particular, metal oxides can be used as the oxide, preferably alkali metal oxides and alkaline earth metal oxides. Suitable examples of the oxide include lithium oxide, sodium oxide, potassium oxide, magnesium oxide, calcium oxide, strontium oxide, and barium oxide, and combinations thereof.

[0045] In particular, metal hydroxides are used as hydroxides, preferably alkali metal and alkaline earth metal hydroxides, Examples of hydroxides include, in particular, lithium hydroxide, sodium hydroxide, potassium hydroxide, calcium hydroxide, barium hydroxide, strontium hydroxide and zinc hydroxide, and combinations thereof.

[0046] Since the foaming additive is present in an aqueous solution, the base is also present in the aqueous solution. Preferably, the base is dissolved in the aqueous solution.

[0047] In an advantageous embodiment of the invention, the aqueous solution is a solution saturated with a base. Due to the high base content, the saturated solution has a particularly high ion concentration. Preferably, the ion concentration corresponds to the solubility product of the respective base. An aqueous solution with such a base concentration remains liquid even below the freezing point of water. As a result, the base also functions as an antifreeze agent. Such saturated solutions are particularly suitable for operation or use in vehicles.

[0048] Particularly preferably, the additive comprises a saturated aqueous solution of sodium carbonate, more preferably a saturated aqueous solution of potassium carbonate, and combinations thereof.

[0049] The inclusion of a base in the foaming additive advantageously makes it possible to directly neutralize the electrolyte based on sulfur dioxide in the form of acid-base neutralization.

[0050] The sulfur dioxide contained in the electrolyte is particularly well absorbed, since it dissolves well in water. The solubility of sulfur dioxide in water is 112.7 g per liter of water at 20 °C. Sulfur dioxide reacts with water to form sulfurous acid, which can react with bases in a neutralization reaction. Bases can therefore convert the sulfur dioxide dissolved in aqueous solution into more stable chemical compounds. For example, sulfur dioxide can be converted by carbonates into stable sulfites or sulfates and / or hydrogen sulfites. Furthermore, bases have the technical advantage of being non-toxic, soluble in water and readily available.

[0051] The foaming additive may include other additives.

[0052] Suitable examples of additives include alkaline earth metal chlorides, flame retardants, higher alcohols and urea, and combinations thereof. The higher alcohols are, in particular, saturated, monohydric to trihydric alcohols having 2 to 12 carbon atoms, whereby the higher alcohols can have primary, secondary or tertiary hydroxyl groups. Examples of alkaline earth metal chlorides include calcium chloride (CaCl 2 ) is particularly preferred.

[0053] The addition of calcium chloride has the technical advantage of increasing the absorption of sulfur dioxide by reaction to insoluble calcium sulfite.

[0054] In a further embodiment of the present invention, the dispensing device includes a reservoir containing a foaming additive and a dispensing pump connected to the reservoir, the dispensing pump being connected to a foam distributor disposed in the interior space of the storage housing.

[0055] Preferably, the reservoir containing the foaming additive is located outside the storage housing. However, the reservoir can also be located within the interior space of the storage housing. The reservoir is used to store the foaming additive before the foam is formed and released into the interior space of the storage housing.

[0056] The advantage of having a reservoir is that the additive can be stored separately from the battery cell, meaning that the foaming additive can be removed from the reservoir only when needed.

[0057] Preferably, the feed pump connected to the reservoir is a high-pressure pump, by means of which the foaming additive can be removed from the reservoir particularly quickly.

[0058] Furthermore, the supply pump is connected to a foam distributor. The invention is not further limited with respect to the foam distributor. In general, all foam distributors known in the prior art can be used that are suitable for releasing a foaming additive, in particular a foaming additive consisting of a foaming agent, at least one base and optionally other additives, into the interior space of the storage housing.

[0059] For example, the foam dispenser may consist of a line, preferably a flexible line, with a nozzle outlet for dispensing the foaming additive. Preferably, the nozzle allows for atomization of the foaming additive, which advantageously increases the contact surface between the additive and the emerging electrolyte.

[0060] In another aspect of the present invention, the safety device further comprises a monitoring device, the monitoring device comprising a battery control system and a sensor unit connected to the battery control system.

[0061] The battery control system is preferably located outside the battery storage device. It is therefore conceivable that the battery control system monitors a number of battery storage devices. The sensor unit is connected to the battery monitoring system and is preferably located within the storage housing.

[0062] In one embodiment, the sensor unit is selected from the group consisting of an optical sensor, a pressure sensor, a temperature sensor, and a chemical sensor.

[0063] In one embodiment, the sensor unit is a spectroscopic gas sensor for detecting gaseous sulfur dioxide.

[0064] In a preferred embodiment, the spectroscopic gas sensor is a non-dispersive infrared sensor.

[0065] If abnormal behavior of at least one battery cell occurs during battery operation, it can be detected by the above-mentioned sensor types. Thus, an increase in pressure, temperature or a change in the atmosphere composition (atmospheric composition) in the storage housing can be detected by the sensor unit. Thus, defects in the battery cells can be recognized directly and without any detours.

[0066] In particular, a gas sensor that is selectively responsive to sulfur dioxide provides direct information regarding the presence of sulfur dioxide in the storage housing: if the gas sensor detects sulfur dioxide in the atmosphere of the storage housing, the sulfur dioxide-based electrolyte will leak out of the battery cell and the corresponding cell will therefore be defective.

[0067] The data collected by the sensor unit is transferred to a battery control system connected to the sensor unit. Typically, the data sent to the battery control system is measurement data collected at a specific time interval.

[0068] In a further aspect of the invention, a battery control system is provided for receiving data from the sensor units and analyzing it for operational or non-operational scenarios.

[0069] The battery control system receives the data from the sensor unit and evaluates it for the presence or absence of defects in the battery cells in the storage housing. Based on the data, the battery control system decides whether to activate an operational or non-operational scenario. If the battery control system registers anomalous data, more precisely data that deviates from expected data, the battery control system initiates an operational scenario. If the data received from the sensor unit matches the expected data, the non-operational scenario is selected.

[0070] In the event of an activation scenario, the dispensing device is activated by the battery control system and foaming additive is released by the foam dispenser to form foam within the storage housing. In the event of a non-activation scenario, the status quo is maintained and the dispensing device is not activated.

[0071] Preferably, the above process is carried out at regular time intervals. This means that the monitoring device can monitor the battery cells in real time and can instantly and reliably record abnormal data such as pressure, temperature and atmospheric (atmosphere) parameters in the storage housing. Thus, the battery control system can also immediately take measures to release additives to neutralize the leaked electrolyte in the inner space of the battery storage device. Therefore, the safety device according to the present invention, consisting of the supply device and the monitoring device, is an active safety system.

[0072] In a further embodiment, the feed apparatus includes a mixer and a circulation pump, the mixer having separate connections to the foam distributor, the feed pump and the circulation pump, and the circulation pump is fluidly connected to the interior space of the storage housing.

[0073] Usually, when foam is released in the internal space of the storage housing, a sufficient amount of electrolyte cannot be immediately fixed and neutralized. The released electrolyte accumulates in the atmosphere of the storage housing over time and usually comes into contact with the released foam only by gas diffusion. In the above-mentioned embodiment, it is advantageous that the circulation pump is flow-connected to the internal space and thus to the atmosphere of the storage housing. This allows the atmosphere of the storage housing to be pumped out and fed back to the storage housing via the mixer and the foam distributor. In other words, the atmosphere circulates in the storage housing. This means that the sulfur dioxide-based electrolyte can be repeatedly brought into contact with the foam. In this way, an almost complete neutralization of the electrolyte is guaranteed.

[0074] In a further embodiment, the battery control system is designed to control the supply device to operate the circulation pump when an operating scenario exists, thereby sucking in the gas atmosphere present in the storage housing and pumping it back into the storage housing via the mixer.

[0075] Preferably, the gas atmosphere removed from the storage housing is fed back to the storage device via a mixer and foam distributor.

[0076] Coupling the circulation pump with the monitoring device has the technical advantage that in addition to foam generation, it also allows for controlled circulation of the gas atmosphere within the storage housing.

[0077] The present invention further relates to a method for activating a safety device of the above type of battery storage device, said method comprising the following steps: a) detecting leakage of electrolyte from a battery cell in the internal space of the storage housing by a sensor unit of the monitoring device, generating data therefrom and transmitting the data to a battery control system; b) evaluating said data for the presence of an operational or non-operational scenario by a battery control system; c) recognizing an actuation scenario; d) controlling the supply device; e) producing a foam from the foaming additive; f) discharging foam into the storage housing interior space; g) Optionally, observing a waiting period. h) Activation of an optional circulation pump, which draws in the gas atmosphere present in the interior space of the storage housing and supplies it again to the interior space via the mixer and foam distributor.

[0078] Thus, the safety device using the above-mentioned method can immediately react and take measures in case of electrolyte leakage from the battery cell. The released foam allows the electrolyte based on sulfur dioxide to be fixed, and the base present in the foam can react with the electrolyte in a neutralizing reaction, in particular with sulfur dioxide, thus reliably preventing the electrolyte from leaking into the environment. [Brief description of the drawings]

[0079] The present invention will now be described in more detail with reference to the accompanying drawings. - Figure 1 is a schematic diagram of a battery storage device with battery cells, a supply device and a monitoring device; - Figure 2 is a schematic diagram of the active operation of the battery storage system of Figure 1 in the event of electrolyte leakage from a defective battery cell; - Figure 3 is a schematic diagram of a gas sensor selectively detecting gaseous sulfur dioxide; FIG. 4 shows an example of a measurement range suitable for the gas sensor of FIG. FIG. 5 is a schematic flow chart showing the steps of a process for activating the safety device of the battery storage device of FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0080] 1 shows a battery storage device 10 equipped with a safety device 32, 37. The safety device 32, 37 comprises a supply device 32 and a monitoring device 37.

[0081] The battery storage device 10 also includes a storage housing 12 and a plurality of battery cells 14 disposed within an interior space 33 of the storage housing 12. In particular, the storage housing 12 is airtight.

[0082] At least one battery cell 14 is disposed in the interior space 33. However, any number of battery cells 14 may be disposed within the storage housing 12. The battery cells 14 may be interconnected (not shown here) to provide a battery having higher energy.

[0083] The battery cells 14 include at least one electrolyte (not shown here) based on sulfur dioxide. In general, the present invention is not further limited with respect to the battery cells 14, so long as the battery cells 14 include sulfur dioxide as an electrolyte.

[0084] For example, a battery cell 14 having an electrolyte composition from WO2021019042A1, WO201504573A2, or the not yet published German patent application No. 102021118811.3 can be used.

[0085] The supply device 32 includes a reservoir 18 that is disposed outside the storage housing 12 .

[0086] The reservoir 18 contains a foaming additive 16 .

[0087] The foaming additive 16 is in an aqueous solution and includes the following components: (A) at least one foaming agent selected from the group consisting of ionic surfactants, saponins and proteins, and combinations thereof; (B) at least one base selected from the group consisting of carbonates, bicarbonates, oxides, and hydroxides, and combinations thereof; and (C) Optionally, further additives selected from the group consisting of alkaline earth metal chlorides, flame retardants, higher alcohols and urea, and combinations thereof.

[0088] The reservoir 18 contains a sufficient amount of the foaming additive 16 to neutralize the sulfur dioxide contained in the battery cells 14. Preferably, the reservoir 18 contains a sufficient amount of the foaming additive 16 to completely neutralize the sulfur dioxide contained in the at least one battery cell 14. Particularly preferably, the reservoir 18 contains an excess amount of the foaming additive 16 relative to the sulfur dioxide-based electrolyte contained in the at least one battery cell 14. The latter is particularly advantageous because when the foaming additive 16 is removed from the reservoir 18, a residue is typically left behind in the reservoir 18.

[0089] The reservoir 18 is fluidly connected by a line 20 to a feed pump 22 that is external to the storage housing 12. The feed pump 22 is connected to a mixer 26 that is also external to the storage housing.

[0090] Mixer 26 is fluidly connected to foam distributor 24 , circulating pump 28 and feed pump 22 via line 20 .

[0091] The foam distributor 24 is disposed in the interior space 33 of the storage housing 12. The foam distributor 24 can be designed as a rigid line or a flexible line. Furthermore, the foam distributor 24 can be disposed anywhere within the storage housing 12. For example, the foam distributor 24 can be attached to an inner wall of the storage housing or fixed to an outer wall of the battery cell 14.

[0092] Furthermore, the foam distributor 24 has an outlet (not shown here) for releasing the foaming additive 16. The outlet can be designed, for example, as a nozzle for distributing the foaming additive 16 into the interior space 33 of the storage housing 12. The release of the foaming additive 16 generates a foam 35 according to the invention for neutralizing the electrolyte. The foam 35 is generated in particular by mixing the foaming additive 16 with the atmosphere in the storage housing 12. In particular, the generation of the foam from the foaming additive 16 is contributed by gas released by the escaping electrolyte.

[0093] Furthermore, a leak 30 is embedded in one wall of the reservoir housing 12. The leak 30 fluidly connects an interior space 33 of the reservoir housing 12 with the circulation pump 28. The leak 30 can be designed, for example, as a valve.

[0094] Furthermore, the safety device comprises a monitoring device 37 .

[0095] The monitoring device 37 comprises a battery control system 36 and a sensor unit 38 connected to the battery control system 36 , the battery control system 36 being arranged within the storage housing 12 .

[0096] The sensor unit 38 can be located anywhere within the storage housing 12. It is therefore contemplated that the sensor unit 38 may be fixed to an inner wall of the storage housing 12. However, the sensor unit 38 may also be attached directly to the battery cell 14.

[0097] In variations of the present invention, multiple sensor units 38 may be positioned at any desired location within storage housing 12. In this manner, different areas of battery storage unit 10 may be monitored by sensor units 38.

[0098] The present invention is not further limited with respect to the sensor unit 38. Any sensor unit commonly used in the prior art suitable for detecting pressure, temperature or atmosphere differences can be used.

[0099] Preferably, the sensor unit is a sensor for selectively detecting sulfur dioxide, preferably gaseous sulfur dioxide in the atmosphere. All sensors known in the art can be used for this purpose.

[0100] For example, sulfur dioxide leaking from a battery can be detected using a known detector known from US 4,222,745. It consists of potassium dichromate adsorbed on finely dispersed silicon dioxide and an adhesive polymeric material, e.g. polydimethylsiloxane, as a stabilizing matrix. Titanium dioxide can also be added to give a strong color recognition. The detector changes color on contact with sulfur dioxide.

[0101] Also contemplated is a detector consisting of the known powdered potassium dichromate known from WO 02079746. This detector is applied to an adhesive strip together with an oxidation promoter and a metal oxide inhibitor and allows in particular the detection of sulfur dioxide.

[0102] Also known is a sensor from US6579722 for detecting gaseous sulfur dioxide, in which a chemiluminescent reagent is immobilized on a polymer film. The chemiluminescence produced on contact with sulfur dioxide is detected by means of a photomultiplier or photoelectric element.

[0103] The known sensor known from JP 2003035705 can also be used, which is suitable for detecting sulfur dioxide in gaseous samples, in which the light transmittance in the UV / VIS / IR range is monitored under the influence of an analyte, and which consists of a combination of Orange-1 and an amine, and of ferric ammonium sulfate, phenanthroline and an acid.

[0104] A sensor designed as a sensor membrane for detecting sulfur dioxide is also known from EP 0585212. Transition metal complexes with ruthenium, osmium, iridium, rhodium, palladium, platinum or rhenium as central atom, 2,2'-bipyridine, 1,10-phenanthroline or 4,7-diphenyl-1,10,phenanthroline as ligands and perchlorate or chloride or sulfate as counter anion are used for this purpose. The polymer matrix is ​​taken from the group of cellulose derivatives, polystyrene, polytetrahydrofuran or their derivatives.

[0105] It is also possible to use the sensor of EP 0578630, which provides a sensor membrane for an optical sensor to detect sulfur dioxide. For this purpose, pH indicators such as the fluorescent dye quinine or the absorbing dye bromocresol purple are immobilized in a polymer matrix made of polyvinyl chloride together with counterions such as long-chain sulfonate ions or ammonium ions with long-chain residues.

[0106] Optical sensors that selectively detect gaseous sulfur dioxide are particularly preferred.

[0107] For example, optical sensors can be used, as known from "Optical sensors for dissolved sulfur dioxide" (A. Stangelmayer, I. Klimant, OS Wolfbeis, Fresenius J. Analytical Chemistry, 1998, 362, 73-76). For the detection of gaseous sulfur dioxide, lipophilic pH-sensing agents in the form of ion pairs immobilized in gas-permeable silicone or OsmoSil membranes are used as sulfur dioxide sensors for gaseous samples. Ditetraalkylammonium salts with long-chain alkyl residues of bromothymol blue, bromocresol purple, bromophenol blue are used as pH indicators. The absorbance of light in the UV / VIS region is used as the measurement variable.

[0108] As is known from DE 10 2004 051 924 A1, optical sensors can also be used to quantitatively determine sulfur dioxide in a sample. The proposed sensor comprises an indicator substance homogeneously immobilized in a transparent sensor matrix, which is in at least indirect contact with the sample and changes its concentration in the presence of sulfur dioxide. The change in concentration of the indicator substance can be monitored photometrically as a change in the light transmittance in the UV / VIS range of the sensor.

[0109] In a particularly preferred variant, the sensor selectively detecting sulfur dioxide is a sensor as depicted in FIG.

[0110] The sensor unit 38 is designed to detect electrolyte leakage from the battery cells 14 and generate and transfer data therefrom to the battery control system 36. The data is transmitted via the electrical connection 34.

[0111] The battery control system 36 is disposed outside the storage housing 12 and is electrically connected to the sensor unit 38 via connections 34. Preferably, the connections 34 are designed to transmit electrical signals and thus data.

[0112] The battery control system 36 can receive data from the sensor unit 38 and evaluate it for operational or non-operational scenarios. If the battery control system registers abnormal data related to changes in temperature, pressure or atmosphere within the storage housing 12, the battery control system 36 activates an operational scenario.

[0113] The battery control system 36 is electrically connected to the feed pump 22 via connection 34. When an operating scenario occurs, the battery control system 36 can specifically control the feed pump 22 such that the feed pump 22 is activated and the foaming additive 16 is fed from the reservoir 18. Thus, the foaming additive 16 enters the foam distributor 24 from the reservoir 18 via line 20 and the feed pump 22, and ultimately releases the foaming additive 16 in the interior space 33 of the storage housing 12, thus generating foam 35.

[0114] After the waiting period, the battery control system 36 can activate the circulation pump 28 via the electrical connection 34, which draws the atmosphere from the interior space 33 and supplies it back to the interior space 33 via the line 20, the mixer 26 and the foam distributor 24. This circulates the atmosphere in the interior space 33, bringing the unneutralized electrolyte components back into contact with the foam 35.

[0115] FIG. 2 illustrates the battery storage device 10 of FIG. 1 when an operational scenario occurs.

[0116] Additionally, FIG. 2 includes the same components as already described in FIG.

[0117] The mechanism of the operating scenario is illustrated below with reference to Fig. 2. If an electrical, thermal or chemical defect occurs in a battery cell 14, this cell 14 may be opened under certain circumstances. Such a battery cell 14 is therefore a defective cell 31. However, a cell 14 may also be damaged without a parallel cell opening occurring. In both cases, however, the parameters of the internal space of the storage housing 12, such as the temperature, pressure, electrical properties of the cell or the composition of the atmosphere, will inevitably change. These parameter changes are detected by the sensor unit 38.

[0118] When a defective cell 31 is opened, the electrolyte based on sulfur dioxide can leak out. The electrolyte can enter the internal space 33 of the storage housing 12 in liquid or gas form. The sensor unit 38 detects the presence of such electrolyte in liquid or gas form in the storage housing in the form of deviating parameters, as described above. These deviating parameters are sent in the form of data as abnormal parameters to the battery control system 36. The battery control system 36 continuously compares the received data with expected data. If a predefined deviation of the received data from the expected data is detected, the battery control system 36 activates an operating scenario. The foaming additive 16 is then taken from the reservoir 18 by the feed pump 22 and is supplied to the foam distributor 24. The foam distributor 24 releases the foaming additive into the internal space 33 of the storage housing 12. This release causes the electrolyte in the internal space 33, the released foaming additive 16 and the atmosphere present in the storage housing 12 to mix. This generates a foam 35 that accumulates in the internal space 33. The foam 35 can immobilize the electrolyte and neutralize it through an acid-base reaction.

[0119] FIG. 3 shows a sulfur dioxide sensor based on a dual beam spectrometer.

[0120] The gas sensor 39 includes a detector chamber 44 surrounded by a detector housing 43. The detector housing 43 further includes a gas inlet opening 41.

[0121] A gas inlet opening 41 fluidly connects the detector chamber 44 with the interior space 33 of the storage housing, allowing free exchange of gas between the two regions, allowing any escaping electrolyte within the storage housing 12 to be detected by the gas sensor 39.

[0122] The detector housing 43 has an elongated shape and the light source 42 is attached within the housing at one end.

[0123] The light source 42 is preferably an infrared light source, particularly preferably a near-infrared light source. The invention is not limited with respect to the infrared light source. All infrared light sources known in the prior art can be used, as long as they are capable of emitting a wavelength suitable for detecting sulfur dioxide in a gas atmosphere.

[0124] Preferably, the light source 42 has a wavelength of 400 to 1800 cm -1 In particular, the range of 450 to 600 cm is preferable. -1 , 1100~1200cm -1 and / or 1300-1400cm -1 In operation, the light source 42 emits a NIR beam 46 having a continuous spectrum of wavelengths in the range described above.

[0125] The NIR beam 46 emitted by the source 42 is split into two spatially separated NIR beams by a measurement beam separator 48 and a reference beam separator 50 located in the detector chamber 44. More precisely, the NIR beam 46 is split into a measurement beam 56 by the measurement beam separator 48 and into a reference beam 58 by the reference beam separator 50. Two beam paths are generated according to the diagram.

[0126] Measurement beam 56 passes through measurement beam separator 48 before being incident on measurement beam filter 52. Reference beam 58 passes through reference beam separator 50 before being incident on reference beam filter 54.

[0127] Suitable measurement beam filters 52 and reference beam filters 54 are, for example, bandpass filters, preferably narrow bandpass filters. For example, the bandpass filters may have a bandwidth of 10-0.2 nm, preferably 5-0.2 nm, particularly preferably 2-0.2 nm. This allows selective filtering of certain wavelengths from the reference beam 58 and measurement beam 56.

[0128] As a reference, the transmission range of the reference beam filter 54 is selected to transmit in a narrow spectral range in which neither sulfur dioxide nor other molecules such as carbon dioxide have absorption bands.

[0129] The transmission range of the measurement beam filter 52, and therefore of the measurement beam 56, is selected so that it is in a range in which only sulfur dioxide is absorbed, but not other gases that may corrupt the measurement signal.

[0130] Examples of suitable wavelengths for measurement beam filters include: 1.56 μm, 1.57 μm, 1.58 μm, 2.46 μm, 4.02 μm.

[0131] After passing through measurement beam filter 52, measurement beam 56 is incident on a measurement beam detector 62 downstream of measurement beam filter 52. Similarly, reference beam 58 is incident on a reference beam detector 60 downstream of reference beam filter 54.

[0132] A detector using a thermocouple, for example, is suitable for detecting the wavelengths transmitted by the filter. A thermocouple can convert thermal energy directly into electrical energy, generating a very low thermal voltage that can be detected. Therefore, the detector used in this method is particularly sensitive and is suitable for detecting small amounts of sulfur dioxide in the atmosphere.

[0133] Figure 4 shows the measurement range of the sulfur dioxide sensor of Figure 3, plotting absorbance against wavelength. The sum of the absorption of the measurement and reference beam detectors 60, 62 is shown.

[0134] The measurement beam detector 62 detects a measurement signal 64 in a measurement wavelength range 68, and the reference beam detector 60 detects a reference signal 66 in a reference wavelength range 70. The reference wavelength range 70 and the measurement wavelength range 68 are predetermined by the selection of the beam filters. Similarly, the width of the measurement wavelength range depends on the selection of the beam filters and is typically 10-0.2 nm, preferably 5-0.2 nm, particularly preferably 2-0.2 nm.

[0135] If the measurement beam detector 62 detects a measurement signal 64, then sulfur dioxide is present in the atmosphere of the detector chamber 44 and therefore also in the interior space of the storage housing 12. A threshold can be established for a positive detection of sulfur dioxide, which is typically above the background noise of the detector.

[0136] An advantage of the illustrated dual beam spectrometer is that it is compact and can be housed within the storage housing 12 to save space. Additionally, because sulfur dioxide is detected spectroscopically, it is easier to evaluate and convert into electronic information compared to conventional methods.

[0137] FIG. 5 is a schematic flow chart illustrating the steps of a procedure for activating the safety features of the battery storage device 10 described above.

[0138] In the first step, leakage of electrolyte from the battery cells is detected (step 1). The detection is performed by a sensor unit of the monitoring device installed inside the storage housing. The sensor unit generates data and transmits it to the battery control system.

[0139] The data is then analyzed by the battery control system to determine if an operational or non-operational scenario occurred (step 2). The battery control system evaluates the parameters measured by the sensor units by comparing them with expected parameters.

[0140] If there is a deviation in the parameters and it is outside the tolerance range, an actuation scenario is executed (step 3). The tolerance range depends on various factors such as the choice of detector and the design of the beam path, and is therefore selected according to the design of the battery storage device and the gas sensor.

[0141] The battery control system then activates the feed device by activating the feed pump, which draws foaming additive from the reservoir and delivers it to a foam dispenser located within the storage housing (step 4).

[0142] In a next step, a foam dispenser produces foam from the foaming additive by contacting the foaming additive with the atmosphere in the interior space of the storage housing (Step 5).

[0143] The generated foam is then released into a storage housing (step 6).

[0144] Afterwards, an optional waiting period can be performed (step 7), which is particularly advantageous since it allows the foam and the leaked electrolyte a certain amount of time to react, during which neutralization can take place.

[0145] After the waiting time, the circulation pump can be optionally operated (step 8). The gas atmosphere in the storage housing can be sucked by the circulation pump and fed back into the storage housing via the mixer and foam distributor. This allows the gas atmosphere in the interior space to be circulated. In this way, the leaked electrolyte accumulated in the atmosphere of the interior space can be efficiently brought into contact with the released foam. Preferably, the circulation pump continues to operate until the sensor unit no longer detects electrolyte in the interior space.

Claims

1. 1. A battery storage device (10) comprising a storage housing (12) and at least one battery cell (14) disposed in an interior space (33) of the storage housing (12) and containing a sulfur dioxide-based electrolyte, the battery storage device (10) having a safety device comprising a supply device (32), the supply device (32) containing a foaming additive (16) and configured to generate a foam (35) from the foaming additive (16) and release the foam (35) into the interior space (33) of the storage housing (12) to neutralize the electrolyte.

2. The foaming additive (16) is present in an aqueous solution and contains the following components: (A) at least one foaming agent selected from the group consisting of ionic surfactants, saponins, and proteins, and combinations thereof; (B) at least one base selected from the group consisting of carbonates, bicarbonates, oxides, and hydroxides, and combinations thereof; and (C) optionally, additional additives selected from the group consisting of alkaline earth metal chlorides, flame retardants, higher alcohols and urea, and combinations thereof; The battery storage device (10) of claim 1, comprising:

3. 3. The battery storage device (10) according to claim 1 or 2, characterized in that the supply device (32) comprises a reservoir (18) containing a foaming additive (16) and a supply pump (22) connected to the reservoir (18), the supply pump (22) being connected to a foam distributor (24) arranged in the interior space (33) of the storage housing (12).

4. 4. The battery storage device (10) of claim 3, wherein the supply device (32) comprises a mixer (26) and a circulation pump (28), the mixer (26) having separate connections to the foam distributor (24), the supply pump (22), and the circulation pump (28), respectively, and the circulation pump (28) is fluidly connected to the interior space (33) of the storage housing (12).

5. 2. The battery storage device (10) according to claim 1, characterized in that the safety device has a monitoring device (37), the monitoring device (37) comprising a battery control system (36) and a sensor unit (38) connected to the battery control system (36).

6. 6. The battery storage device (10) according to claim 5, characterized in that the sensor unit (38) is selected from the group consisting of an optical sensor, a pressure sensor, a temperature sensor and a chemical sensor, more preferably the sensor unit is a spectroscopic gas sensor (39) for detecting gaseous sulfur dioxide.

7. 7. The battery storage device (10) according to claim 6, characterized in that the sensor unit (38) is designed to detect electrolyte leakage from the battery cells (14), generate data therefrom and transfer it to the battery control system (36), the battery control system (36) being arranged to receive the data from the sensor unit (38) and evaluate it with respect to an operating or non-operating scenario.

8. 8. The battery storage device (10) of claim 7, wherein the battery control system (36) is further designed to control the supply device (32) when an operating scenario exists, so that foam (35) is generated from the foaming additive (16) and released into the interior space (33) of the storage housing (12).

9. 9. The battery storage device (10) according to claim 8, characterized in that the battery control system (36) is further designed to control the supply device (32) to operate the circulation pump (28) when an operating scenario exists, wherein the circulation pump (28) sucks the gas atmosphere present in the storage housing and supplies it again to the storage housing via the mixer and foam distributor.

10. 10. A method of activating a safety device in a battery storage device (10) according to claim 9, comprising the steps of: (a) detecting leakage of electrolyte from the battery cells (14) in the interior space (33) of the storage housing (12) by the sensor unit (38) of the monitoring device (37), whereby data is generated therefrom and transmitted to the battery control system (36); (b) evaluating, by a battery control system (36), said data for the presence or absence of an operational or non-operational scenario; (c) recognizing an actuation scenario; (d) controlling the feeding device (32); (e) producing a foam (35) from the foaming additive (16); (f) releasing foam (35) into the interior space (33) of the storage housing (12); (g) optionally observing a waiting period; (h) optionally, operating the circulation pump (28), which aspirates the gas atmosphere present in the interior space (33) of the storage housing (12) and feeds it back into the storage housing (12) via the mixer (26) and the foam distributor (24); The method, comprising:

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