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

Abstract

The present invention relates to a battery storage device (10) comprising a storage housing (12) and at least one battery cell (14) disposed within the storage housing (12) and containing a sulfur dioxide-based electrolyte, the battery storage device (10) having a safety device comprising a supply device (34), the supply device (34) containing an additive (16) for neutralizing the electrolyte and designed to release the additive (16) into 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 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 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 ).

[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. In particular, sulfur dioxide-based electrolyte compositions have improved ionic conductivity, allowing the operation of battery cells at high discharge currents without adversely affecting the stability of the battery cells. Furthermore, certain sulfur dioxide-based electrolyte compositions are particularly suitable for the construction of cells with high energy density due to their increased upper voltage limit. In particular, cells using sulfur dioxide-based electrolytes have a significant advantage over conventional organic electrolytes and LiPF 6 It has a higher voltage limit than cells containing rich conductive salts.

[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] EP1201004B1 [Patent Document 2] EP2534719B1 [Patent Document 3] WO2015 / 043573A2 [Patent Document 4] WO2021 / 019042A1 [Patent Document 5] German Patent Application No. 102021118811.3 [Patent Document 6] EP3703161A1 [Patent Document 7] EP2227838B1 [Patent Document 8] EP2742551B1 [Patent Document 9] EP3771011A2 [Patent Document 10] WO2005 / 031908A2 [Patent Document 11] WO2014 / 121803A1 Summary of the Invention [Problem to be solved by the invention]

[0017] A drawback of battery cells, particularly lithium-ion battery cells having a sulfur dioxide-based electrolyte composition, is that the cell may open if the cell experiences a mechanical, electrical, or thermal failure, which may result in electrolyte components, particularly gaseous electrolyte components such as sulfur dioxide, being 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 according to claim 1, which comprises a storage housing and at least one battery cell with an electrolyte based on sulfur dioxide.

[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 inside the storage housing and containing an electrolyte based on sulfur dioxide, the battery storage device comprising a safety device with a supply device which contains an additive for neutralizing the electrolyte and is designed to release the additive inside the storage housing.

[0022] The basic idea of ​​the present invention is that the battery storage device is equipped with a safety device that neutralizes or binds the sulfur dioxide-based electrolyte that escapes from the cell by releasing an additive, preventing the electrolyte from escaping into the environment.

[0023] Preferably, the battery storage unit is installed on board a vehicle and used to electrically drive the vehicle, although of course, such a vehicle may be equipped with multiple battery storage units.

[0024] 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 within the interior space of the battery storage device. The battery cells can be interconnected within the storage housing to provide higher levels of energy.

[0025] The battery cells are electrochemical cells with a sulfur dioxide based electrolyte, preferably the battery cells are lithium ion batteries.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] The battery storage device is equipped with a safety device in case of mechanical, thermal or electrical damage to the cells or leakage of the sulfur dioxide-based electrolyte, which includes a supply device with an additive for neutralizing or binding the electrolyte and is configured to release the additive within the storage housing, so that leakage of the electrolyte can be directly, easily and safely neutralized.

[0030] For the purposes of the present invention, neutralization of an electrolyte is understood to mean a chemical neutralization that converts the electrolyte components into chemically more stable, stable and non-toxic compounds.

[0031] Furthermore, since the neutralization of the electrolyte is already performed in the storage housing of the battery storage device, it is easy to prevent the leaked electrolyte from escaping into the environment. Since the storage housing is sealed against liquid leakage, the additive, the electrolyte, the resulting harmless reaction products and other components remain in the battery storage device after neutralization. The storage housing thus provides a limited reaction chamber in which the neutralization can be carried out under controlled conditions. Advantageously, once the neutralization is completed, the battery storage device can be safely disposed of separately or put into a recycling process.

[0032] In one embodiment of the present invention, the additive 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 additive.

[0033] For example, the base can be porous natural lime.

[0034] Preferably, the base is selected from the group consisting of carbonates, bicarbonates, oxides, hydroxides and combinations thereof.

[0035] 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.

[0036] In particular, metal bicarbonates are used as bicarbonates, preferably alkali metal bicarbonates and alkaline earth metal bicarbonates. Suitable examples of bicarbonates include calcium bicarbonate, magnesium bicarbonate, barium bicarbonate, sodium bicarbonate and potassium bicarbonate, and combinations thereof.

[0037] In particular, the oxide may be a metal oxide, preferably an alkali metal or alkaline earth metal oxide. Suitable examples of the oxide include lithium oxide, sodium oxide, potassium oxide, magnesium oxide, calcium oxide, strontium oxide, barium oxide, and combinations thereof.

[0038] 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.

[0039] The additive may also include water. Thus, the base is present in an aqueous solution. Preferably, the base is dissolved in the aqueous solution.

[0040] In another 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 (base concentration) corresponds to the solubility product of the respective base. As a result, the solution remains liquid even below the freezing point of water. The saturated solution is therefore particularly suitable for operation or use in vehicles.

[0041] Particularly preferably, the additive comprises a saturated aqueous solution of sodium carbonate, more preferably a saturated aqueous solution of potassium carbonate, or a combination thereof.

[0042] The provision of a base in the aqueous solution allows the chemical neutralization of electrolytes based on sulfur dioxide in the form of acid-base neutralization. The sulfur dioxide contained in the electrolyte is particularly soluble in water and can therefore be absorbed and bound particularly quickly by additives. The solubility of sulfur dioxide in water is 39.4 liters per liter of water at 20 °C and normal pressure. Sulfur dioxide reacts with water to form sulfurous acid, which reacts with the base in a neutralization reaction. The base can therefore convert the sulfur dioxide dissolved in the 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.

[0043] In addition, the base used is non-toxic, easily soluble in water, and readily available when needed. Since the base is present in an aqueous medium, it can be easily released into the storage housing by the supply device. This means that when the electrolyte is released, the base dissolved in the aqueous solution can wet the battery cells in the storage device, thus preventing the electrolyte from leaking into the environment.

[0044] In another embodiment of the invention, the supply device comprises a reservoir containing the additive and a pump connected to the reservoir, the pump being connected via a valve to a distributor, at least the distributor being disposed within the storage housing.

[0045] Preferably, the reservoir is located outside the storage housing. However, it is also conceivable to locate the reservoir in the interior space of the storage housing. The reservoir is used to store the additive before actually releasing it. By providing a reservoir containing the additive, the additive can be stored separately from the battery cell.

[0046] Preferably, the pump connected to the reservoir is a high-pressure pump. Furthermore, the pump is connected to the distributor via a valve. By using the pump, especially the high-pressure pump, the additive can be rapidly transported from the reservoir to the distributor and thus to the inner space of the storage housing. This ensures efficient and rapid release of the additive in the storage housing.

[0047] The invention is not further limited with respect to the dispenser: in general, all dispensers known in the prior art suitable for releasing an additive in a storage housing, in particular an additive consisting of an aqueous solution with a base, can be used.

[0048] For example, the distributor may consist of a line, preferably a flexible line, with a nozzle outlet for distributing the additive. Preferably, the nozzle allows atomization of the additive, which increases the contact surface between the additive and the emerging electrolyte.

[0049] 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.

[0050] The battery control system is preferably located outside the battery storage device. It is therefore conceivable that the battery control system monitors a plurality of battery storage devices. The sensor unit is connected to the battery monitoring system and is preferably located within the storage housing.

[0051] 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.

[0052] In one embodiment, the sensor unit is a spectroscopic gas sensor for detecting gaseous sulfur dioxide.

[0053] In a preferred embodiment, the spectroscopic gas sensor is a non-dispersive infrared sensor.

[0054] 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.

[0055] 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] In the event of an activation scenario, the supply device is activated by the battery control system and additive is released through a dispenser within the storage housing. In the event of a non-activation scenario, the status quo is maintained and the supply device is not activated.

[0060] Preferably, the above process is carried out at regular time intervals, which 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, atmospheric parameters, etc. in the storage housing. Therefore, the battery control system can also immediately take measures to release additives inside the battery storage device to neutralize the leaked electrolyte.

[0061] As a result, the safety device according to the invention comprising the supply device and the monitoring device is an active safety system, which can therefore actively initiate measures in the event of electrolyte leakage from the cell.

[0062] 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 inside 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) activating the dispenser to release foam into the storage housing.

[0063] Therefore, the safety device using the above method can immediately react and take measures when electrolyte leaks from the battery cell, thereby reliably preventing electrolyte containing sulfur dioxide as a main component from leaking into the environment. [Brief description of the drawings]

[0064] 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 the 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 a safety device of a battery storage device. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0065] 1 shows a reservoir unit 10 equipped with a safety system. The safety system includes a supply device 34 and a monitoring device 36.

[0066] The battery storage device 10 also includes a storage housing 12 and a plurality of battery cells 14 disposed within an interior space 40 of the storage housing 12. In particular, the storage housing 12 is sealed against the escape of liquids. To control the escape of gases, the storage housing may also include a pressure regulator or pressure relief valve (not shown here).

[0067] At least one battery cell 14 is disposed in the interior space 40. However, any number of battery cells may be disposed within the storage housing 12. In particular, the battery cells 14 may be interconnected (not shown here) to provide a battery having higher energy. Furthermore, the arrangement of the battery cells 14 within the storage housing 12 is arbitrary and is not further limited.

[0068] The battery cells 14 include at least one electrolyte 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 include sulfur dioxide as an electrolyte component.

[0069] For example, a battery cell 14 having an electrolyte composition from WO2021 / 019042A1, WO2015 / 04573A2, or the not yet published German patent application No. 102021118811.3 can be used.

[0070] The supply device 34 includes a reservoir 26 that contains the additive 16 .

[0071] The reservoir 26 contains a sufficient amount of additive 16 to neutralize all of the sulfur dioxide contained in the battery cells 14. Preferably, the reservoir 26 contains an excess of additive 16 relative to the sulfur dioxide-based electrolyte contained in the battery cells 14. This is particularly advantageous because when the additive 16 is removed, a residue is typically left behind in the reservoir 26.

[0072] The reservoir 26 is connected to the pump 22 via a pipe 24 .

[0073] Pump 22 is also fluidly connected to valve 20 .

[0074] Valve 20 is embedded in the wall of storage housing 12 and fluidly connects an interior space 40 of storage housing 12 to pump 22 and thus to reservoir 26 .

[0075] The distributor 18 is connected to a valve 20 and is disposed within the storage housing 12 .

[0076] The distributor 18 may be a rigid or flexible line. The distributor 18 may be located anywhere within the storage housing 12. For example, it may be secured to an inner wall of the storage housing 12 or an outer wall of the battery cell 14.

[0077] Furthermore, the distributor 18 has an outlet (not shown here) for releasing the additive, which can be designed, for example, as a nozzle for spraying the additive 16 released into the interior space 40 of the storage housing 12. In this way, the contact surface between the released electrolyte and the additive 16 can be increased.

[0078] Furthermore, the safety device comprises a monitoring device 36 .

[0079] The monitoring device 36 includes a battery control system 30 and a sensor unit 28 connected to the battery control system 30 , the battery control system 30 being disposed within the storage housing 12 .

[0080] The sensor unit 28 can be located anywhere within the storage housing 12. It is therefore contemplated that the sensor unit 28 may be fixed to an inner wall of the storage housing 12. However, the sensor unit 28 may also be attached directly to the battery cell 14.

[0081] In variations of the present invention, multiple sensor units 28 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 28.

[0082] The present invention is not further limited with respect to the sensor unit 28. Any sensor unit commonly used in the prior art suitable for sensing pressure, temperature or atmospheric (ambient) differences can be used.

[0083] Preferably, the sensor unit is a sensor for selectively detecting sulfur dioxide, preferably gaseous sulfur dioxide in air. For this purpose, all sensors known in the art can be used.

[0084] 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.

[0085] 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, which allows in particular the detection of sulfur dioxide.

[0086] 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 tube or a photoelectric element.

[0087] The known sensor known from JP 2003035705 A1 may 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.

[0088] 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.

[0089] 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.

[0090] Optical sensors that selectively detect gaseous sulfur dioxide are particularly preferred.

[0091] 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 indicators 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 radicals 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.

[0092] 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.

[0093] In a particularly preferred variant, the sensor selectively detecting sulphur dioxide is a sensor as depicted in FIG.

[0094] The sensor unit 28 is configured to detect electrolyte leakage from the battery cells 14 and generate and transfer data therefrom to the battery control system 30. The data flows from the sensor unit 28 to the battery control system 30 via a data line 33.

[0095] The battery control system 30 is disposed outside the storage housing 12 and is electrically connected to the sensor unit 28 via a data line 33. Preferably, the data line 33 is designed to transmit electrical signals and thus data.

[0096] The battery control system 30 can receive data from the sensor unit 28 and evaluate it for operational or non-operational scenarios. If the battery control system registers anomalous data related to changes in temperature, pressure or atmosphere within the storage housing 12, the battery control system 30 triggers an operational scenario.

[0097] The battery control system 30 is electrically connected to the pump 22 via connection 32. When an operating scenario occurs, the battery control system 30 can specifically control the pump 22 such that the pump 22 is activated and dispenses the additive 16 from the reservoir 26. Thus, the additive 16 flows from the reservoir 26 through the line 24, the pump 22, through the valve 20 and into the distributor 18, ultimately discharging the additive 16 within the storage housing 12.

[0098] FIG. 2 illustrates the battery storage device of FIG. 1 when an operational scenario occurs.

[0099] Additionally, FIG. 2 includes the same components already described in FIG.

[0100] The mechanism of the operating scenario is as follows:

[0101] When at least one battery cell 14 is damaged, the sulfur dioxide-based electrolyte escapes from the damaged cell. Damage to a cell may also occur without simultaneous cell opening. In either case, however, the parameters of the interior space of the storage housing 12 will inevitably change, such as the temperature, pressure or atmospheric composition. Changes in these parameters are detected by the sensor unit 28.

[0102] For example, if sulfur dioxide-based electrolyte leaks out when the cell is opened, it will also accumulate in the atmosphere of the storage housing 12 and be detected by the sensor unit 28 focused on atmospheric parameters.

[0103] The sensor unit 28 detects the presence of electrolyte in the storage housing 12 in the form of deviating parameters regarding pressure, temperature or atmospheric composition and transfers the abnormal parameters in the form of data to the battery control system 30. The battery control system 30 continuously compares the received data with expected data. If a deviation between the received data and the expected data is detected, the battery control system 30 activates an operating scenario. The additive 16 is then released from the reservoir 26 by the pump 22 through the distributor 18. The additive 38 thus released wets the interior space 40 of the storage housing 12, comes into contact with the sulfur dioxide-based electrolyte and reacts with the electrolyte in a neutralization process, in particular an acid-base neutralization process, making it possible to prevent the electrolyte from escaping into the environment.

[0104] FIG. 3 shows a sulfur dioxide sensor based on a dual beam spectrometer.

[0105] 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.

[0106] A gas inlet opening 41 fluidly connects the detector chamber 44 with the interior space 40 of the storage housing. This allows for free exchange of gas between the two regions, and any escaping electrolyte within the storage housing 12 can be detected by the gas sensor 39.

[0107] The detector housing 43 has an elongated shape and the light source 42 is attached within the housing at one end.

[0108] 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.

[0109] Preferably, the light source 42 has a wavelength of 400 to 1800 cm -1In 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.

[0110] 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.

[0111] 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.

[0112] 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.

[0113] For reference, the transmission range of the reference beam filter 54 is selected to transmit a narrow range of the spectrum in which not only sulfur dioxide but also other molecules such as carbon dioxide, or water vapor, have no absorption bands.

[0114] 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.

[0115] Examples of suitable wavelengths for measurement beam filters include: 1.56 μm, 1.57 μm, 1.58 μm, 2.46 μm, 4.02 μm.

[0116] 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.

[0117] 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.

[0118] 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.

[0119] 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.

[0120] 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.

[0121] 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.

[0122] FIG. 5 is a schematic flow chart showing the steps of a procedure for activating the safety device of the battery storage device described above.

[0123] The first step is to detect electrolyte leakage from the battery cells. 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 (step S1).

[0124] The data is then analyzed by the battery control system to determine whether an operational or non-operational scenario occurred (step S2). The battery control system evaluates the parameters measured by the sensor units by comparing them with expected parameters.

[0125] If there is a deviation in the parameters, which is outside the tolerance range, an actuation scenario is executed (step S3). The tolerance range depends on various factors such as the choice of detector and the design of the beam path, and therefore needs to be selected according to the design of the battery storage device and the gas sensor.

[0126] Finally, the battery control system operates the supply device by activating a pump, which draws additive from the reservoir and releases it through a valve and distributor within the storage housing (step S4).

Claims

1. 1. A battery storage device (10) comprising a storage housing (12) and at least one battery cell (14) disposed within the storage housing (12) and containing a sulfur dioxide-based electrolyte, the battery storage device (10) having a safety device comprising a supply device (34), the supply device (34) containing an additive (16) for neutralizing the electrolyte and designed to release the additive (16) into the storage housing (12).

2. 2. The battery storage device (10) of claim 1, wherein the additive (16) comprises a base and is present in an aqueous solution, the base preferably being selected from the group consisting of carbonates, bicarbonates, oxides and hydroxides, and combinations thereof.

3. 3. The battery storage device (10) according to claim 1 or 2, characterized in that the supply device (34) comprises a reservoir (26) containing the additive (16) and a pump (22) connected to the reservoir (26), the pump (22) being connected via a valve (20) to a distributor (18) arranged in the storage housing (12).

4. 3. The battery storage device (10) according to claim 1 or 2, characterized in that the safety device further comprises a monitoring device (36), the monitoring device (36) comprising a battery control system (30) and a sensor unit (28) connected to the battery control system (30).

5. 5. The battery storage device (10) of claim 4, characterized in that the sensor unit (28) is selected from the group consisting of an optical sensor, a pressure sensor, a temperature sensor and a chemical sensor.

6. 5. The battery storage device (10) of claim 4, wherein the sensor unit (28) is a spectroscopic gas sensor (39) for detecting gaseous sulfur dioxide.

7. 5. The battery storage device (10) according to claim 4, characterized in that the sensor unit (28) is designed to detect electrolyte leakage from the battery cells (14), generate data therefrom and transmit it to the battery control system (30).

8. 8. The battery storage device (10) of claim 7, characterized in that a battery control system (30) is provided for receiving data from the sensor unit (28) and evaluating it with respect to an operating or non-operating scenario.

9. 9. The battery storage device (10) of claim 8, wherein the battery control system (30) is further designed to operate the supply device (34) when an operating scenario exists, such that the additive (16) is released by the distributor (18) in the storage housing (12).

10. 10. A method of operating a safety device in a battery storage device (10) according to claim 9, comprising the steps of: a) detecting electrolyte leakage from the battery cells (14) in the storage housing (12) by the sensor unit (28) of the monitoring device (36), whereby data is generated therefrom and transmitted to the battery control system (30); b) evaluating said data with respect to the presence or absence of an operational or non-operational scenario by a battery control system (30); c) recognizing an actuation scenario; d) activating the supply device (34) so ​​that the additive (16) is released into the storage housing (12); The method, comprising:

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