Battery storage system with spark trap, as well as device and method for the corresponding gas treatment

Abstract

The present invention relates to a battery storage device (100) with a spark trap, a corresponding device (40), and a method. The device (40) comprises a liquid volume (43) which is contained in a section (X) of a discharge section (S) of a discharge channel (30), wherein the liquid volume (43) fills a flow cross-section (Q) to be passed through in the section (X), for immersive gas scrubbing of the outgassing during flow through the liquid volume (43).

Description

[0001] The present invention relates to a battery storage device with a spark trap device, as well as a corresponding device and a method for gas treatment of outgassing from a battery cell.

[0002] The invention is used in the construction of battery storage systems, such as a modular construction of battery modules of a traction battery in an electrically powered vehicle or a stationary energy storage system.

[0003] Modular battery storage systems are known to have high energy density and require special safety features to prevent, as far as possible, a spreading chain reaction among the battery cells in the event of thermal runaway, which can occur with some flammable active materials in lithium-ion batteries. These safety features include, among other things, a vent through which hot exhaust gases and their thermal load can be dissipated to the outside in a controlled manner.

[0004] If the battery storage system is located on board a vehicle, especially in close proximity to a passenger compartment, there are also further safety regulations regarding a permissible thermal load, which is dissipated to a limited extent by exhaust gas in the system environment of the vehicle, such as in particular a maximum temperature or the avoidance of sparks and glowing particles on which gases can ignite.

[0005] In the prior art, spark traps are known to consist of structures with deflections of a flow path for outgassing according to the principle of a labyrinth, or surface elements inclined against a flow direction, which cause a separation of heavier particles of a solid phase from a lighter gas phase of these outgassings.

[0006] On the other hand, vehicle manufacturing is constantly driven by the pursuit of space, weight, and cost optimization, which often limits the design freedom for constructive solutions such as spatially demanding or complex designs for outgassing flow paths. Due to the increasing electrification of numerous mobile applications, there is a fundamental need for solutions addressing the safety-relevant behavior of battery storage systems when high temperatures and pressures occur as a result of a malfunction in a battery cell.

[0007] One objective of the invention is to create a technique for the improved treatment of outgassing and waste heat in thermally critical incidents in battery storage systems.

[0008] The foregoing problem is solved by a battery storage device having the features of claim 1, a device having the features of claim 12, and a method having the features of claim 17. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings.

[0009] Features and details described in connection with the battery storage device according to the invention naturally also apply to the device and method according to the invention, so that mutual reference can always be made to the individual aspects of the invention with regard to the disclosure.

[0010] The battery storage device according to the invention has at least one battery cell and comprises a housing with a receiving chamber separated from the surrounding atmosphere for receiving the at least one battery cell; a discharge channel with a discharge section separated from the receiving chamber for spatially separate discharge of outgassing from the at least one battery cell; furthermore, comprising: at least one channel inlet opening directed towards the at least one battery cell for introducing the outgassing from the at least one battery cell into the discharge channel; a channel outlet opening directed towards the surrounding atmosphere for venting the outgassing from the housing into the surrounding atmosphere; and a spark trap device arranged between the at least one channel inlet opening and the channel outlet opening in the discharge section of the discharge channel.

[0011] The essential aspect of the invention is that the spark trap device comprises a liquid volume which is contained in a section of the discharge path of the discharge channel, wherein the liquid volume fills a flow cross-section to be passed through in the section, for an immersive gas scrubbing of the outgassing during the flow through the liquid volume.

[0012] The device according to the invention also serves for cooling and wet separation of solids from outgassing from a battery cell. For this purpose, the device also comprises a discharge channel, which can be fluidly connected to the battery cell and has a defined discharge section, for removing the outgassing from the battery cell. Essentially, the device comprises a liquid volume contained in a section of the discharge channel, wherein the liquid volume fills a flow cross-section to be traversed in that section, for immersive gas scrubbing of the outgassing as it flows through the liquid volume.

[0013] An independent definition of the device according to the invention, i.e., separate from the battery storage device according to the invention, is based on the fact that it represents a potentially separately tradable, smallest unit for implementing the technology according to the invention with a multiple functionality and mode of operation described below in the aforementioned application context of the invention.

[0014] The inventive method also serves for the gas treatment of outgassing from a battery cell and comprises the step: - Discharge of the outgassing from the battery cell along a discharge path into the surrounding atmosphere.

[0015] Essential to the invention, the method further comprises the following step: - Immersive washing of the outgassing by means of a flow passage leading through a liquid volume, which passes the outgassing along the discharge path, for cooling and wet separation of solids from the outgassing.

[0016] The invention thus provides, for the first time, a liquid-based gas filter or gas scrubber for outgassing from battery cells.

[0017] In this process, the outgassing must pass through a liquid phase passage in a discharge section, whereby the outgassing, in the form of a bubble column guided along a section of the passage, is forced through the filter fluid. The liquid volume is arranged such that it occupies a flow cross-section to be passed through; that is, a flow passage is formed through the liquid volume, which carries the outgassing along the discharge section.

[0018] This results in gas scrubbing, in which the outgassing of solids, such as spark-forming, glowing particles, is cleaned and cooled. The comparison to gas scrubbing refers less to a principle of liquid atomization than to a principle of immersion in a bath. In other words, the device and process technology according to the invention employs an operating principle comparable to that of a water pipe.

[0019] The invention effectively achieves several functions. Firstly, it functions as an effective spark trap, based on the principle of wet separation of a solid phase of the outgassing, particularly spark-forming, glowing particles. Secondly, it functions as an effective particle filter, based on the principle of retaining the separated solid phase of the outgassing, such as fine dust or solid components of flue gas, by binding the particles in a suspension. Thirdly, it functions as an effective liquid-based cooler for gas escaping into the system environment, based on the principle of immersive, direct liquid cooling of the retained solid phase and the passed-through gas phase of the outgassing.

[0020] Considerable advantages of the invention consist in the improved efficiency, i.e., the superior efficiency compared to previously known gas flow and spark trap designs, which results from the liquid-based principle, with regard to all three previously mentioned functionalities, namely a spark trap, a particle filter and a cooler.

[0021] Further advantages of the invention lie in the reduced need for installation space and, if applicable, a lower resulting product mass. This can be illustrated by comparing a suitable liquid volume in the technology according to the invention with the length and more complex design of a flow path that would be required in conventional technology to achieve similar effects with regard to particle separation and cooling of outgassing from battery cells.

[0022] Naturally, this comparison is accompanied by economic advantages of a simpler system environment design and lower manufacturing costs for a design according to the inventive technology.

[0023] According to one aspect of the invention, the spark trap device can comprise at least one gas-permeable membrane in the flow cross-section for limiting the liquid volume in the section of the discharge path. Such semipermeable membranes are readily available at low cost and enable effective retention of the liquid as a gas phase passes through.

[0024] According to one aspect of the invention, the spark trap device can comprise at least one pressure-opening valve in the flow cross-section for limiting the liquid volume in the section of the discharge path. Suitable valve types, such as a pressure relief valve in particular, can be preconfigured to predefined threshold values ​​for pressure differences.

[0025] According to one aspect of the invention, the spark trap device can comprise an open reservoir in which the flow cross-section is arranged in a lowered position for gravimetric integration of the liquid volume into the section of the discharge path. A suitable design of the reservoir can range from the simplest form, such as a siphon, to more complex, labyrinthine shapes for improved suitability in mobile applications.

[0026] According to one aspect of the invention, the at least one battery cell can comprise a pressurised vent section for pressure-reducing outflow of the outgassing from the at least one battery cell. This ensures a defined, directed discharge of hot gases.

[0027] According to one aspect of the invention, the outflow section can be designed in the form of a predetermined breaking point in a cell casing of the at least one battery cell.

[0028] According to one aspect of the invention, the outflow section can be designed in the form of a pressure valve in the cell casing of the at least one battery cell.

[0029] According to one aspect of the invention, the at least one inlet opening of the discharge channel can be adjacent to the outlet section of the at least one battery cell and / or be in contact with the cell casing.

[0030] According to one aspect of the invention, the at least one inlet opening of the discharge channel can enclose the outflow section of the at least one battery cell and / or a circumference of the cell casing.

[0031] According to one aspect of the invention, a pressurised outlet valve can be arranged in the outlet opening of the discharge channel. This keeps contaminants from the surrounding environment away.

[0032] According to one aspect of the invention, the liquid volume can contain a dielectric fluid. These are, for example, oil-based, do not evaporate, are non-corrosive, and do not pose a short-circuit risk upon contact with electrical conductors.

[0033] Further advantages, features, and details of the invention will become apparent from the following description, in which exemplary embodiments of the invention are described in detail with reference to the drawings. The features and embodiments mentioned in the claims and in the description can each be essential to the invention individually or in any combination. The drawings schematically illustrate: Fig. 1 a battery storage device with a spark trap device in a first embodiment; Fig. 2 a battery storage device with a spark trap device in a second embodiment; Fig. 3 a battery storage device with a spark trap in a third embodiment; and Fig. 4 a battery storage device in an embodiment with a modification of an input section of the discharge channel.

[0034] Fig. Figure 1 shows a schematic diagram of a storage device 100 with a housing 20 enclosing a receiving chamber 21 for a plurality of battery cells 10. The battery cells 10 are contained within the receiving chamber 21, isolated from any environment such as a system environment or the surrounding atmosphere, i.e., in particular from the air of an ambient atmosphere, in order to prevent external influences and contamination. The battery cells 10 are arranged in one or more adjacent and compact groups within the receiving chamber 21. The active materials, separators, electrodes, and electrolyte of each battery cell 10 are surrounded by a cell jacket 12, which encloses all outer surfaces of a cylindrical or prismatic cell or a pouch cell, thus providing protective isolation from the atmosphere of the receiving chamber 21.

[0035] Each battery cell 10 has a vent section 13 in its casing 12. This vent section is designed as a predetermined breaking point the thickness of the casing 12, or, in a more functionally precise version, as an outwardly directed one-way valve. The vent sections 13 serve to enable a controlled and targeted pressure release of outgassing, such as combustion gases from the interior of the battery cell 10, in the event of a malfunction such as a short circuit, excessive charging or discharging currents, or other causes that could lead to excessive heating or ignition of the battery cell 10. Such outgassing includes hot, potentially flammable combustion gases and particles that begin to glow upon contact with oxygen. Sparking poses a fire hazard to the entire battery storage system 100.

[0036] In the illustrated arrangement, the outflow sections 13 are positioned downwards in a base surface of the cell casing 12. Below the battery cells 10, a discharge channel 30 is arranged in the illustrated embodiment for the removal of outgassing from such thermal incidents. The discharge channel 30 has a defined flow cross-section, which is specifically separated from the receiving chamber 21 of the housing 20, in order to dissipate the thermal load of outgassing spatially separated from the battery cells 10 and in a predetermined orientation. This prevents the released heat from the outgassing from also heating and overheating other intact battery cells 10 adjacent to the defective battery cell 10, i.e., a thermal chain reaction or thermal runaway in the compact arrangement of battery cells 10 is prevented as far as possible.

[0037] In the discharge channel 30, corresponding inlet openings 31 are formed opposite the outlet sections 13 of the battery cells 10, each of which is in sealing contact with the cell casing 12. In the event of a thermal incident in any battery cell 10, the outlet section 13 in the cell casing 12 opens when there is a corresponding overpressure in the defective battery cell 10, and a pressure drop releases gas through one of the correspondingly positioned inlet openings 31 into the discharge channel 30. The discharge channel 30 defines a discharge path S along which the gas is carried away from the battery cells 10 and finally out of the housing 20 of the battery storage unit 100. For this purpose, the discharge channel 30 has an outlet opening 32, which is formed in a wall of the housing 20 or extends through the housing 20 to the surrounding atmosphere.To prevent external influences or contamination through the outlet opening 32, a pressure-opening valve 33, i.e. a one-way valve, pressure valve, check valve, is arranged.

[0038] In the present embodiment, a spark trap device 40 is arranged in a section X of the discharge section S of the discharge channel 30. The spark trap device 40 is also a multifunctional device 40, which fulfills further functions described above.

[0039] At the in Fig. In the first embodiment shown in Figure 1, the spark trap device 40 comprises two gas-permeable membranes 41 that confine a liquid volume 43. Both the membranes 41 and the liquid volume level occupy an entire flow cross-section Q of the discharge channel 30 at any position or extent within the section X. The outgassing, which escapes along the discharge path S based on a pressure difference between the discharge channel and the surrounding atmosphere, diffuses through the first of the two membranes 41, then passes through the liquid volume 43 in the form of a generally horizontal column of bubbles, and finally diffuses through the second membrane 41.As the fluid passes through the liquid volume 43, the glowing particles and other solids from the flue gas, such as soot, are bound, retained, and cooled by direct contact with the liquid phase, according to the principle of wet separation. Furthermore, the bubble-like volumes of the gas phase that continue to pass through are cooled by direct contact with the liquid phase, i.e., by immersion cooling.

[0040] After passing through the spark trap device 40, the remaining gas phase escapes further along the discharge path S through the valve 33 in the outlet opening 32 of the discharge channel 30 from the housing 20 of the battery storage unit 100. As a result of the gas treatment in the spark trap device 40, i.e., the wet separation and immersion cooling of the remaining gas phase, there is no or a significantly lower hazard from ignition due to sparking and the temperature of a potentially flammable gas, as well as from the thermal load released to the outside during outgassing in general.

[0041] Fig. Figure 2 shows a battery device 100 with a second embodiment of the spark device 40. While the remaining features of the battery device 100 are the same as those shown in Figure 2, the battery device 100 is a battery device 100 with a second embodiment of the spark device 40. Fig. In contrast to the spark device 40, the spark device 40 differs in the functional design of a gas-permeable containment of the liquid volume 43. The spark device 40 has a pressure-opening valve 42 on each side, i.e., a one-way valve, pressure valve, or check valve. Both valves 42 occupy the entire flow cross-section Q of the discharge channel 30 in order to contain the liquid volume 43 in the section X. Likewise, the liquid volume 43 occupies a flow cross-section Q within the section X, thus completely filling it, to create an effective liquid phase barrier for the outgassing gas flow.

[0042] Fig. Figure 3 shows another battery device 100 with a third embodiment of the spark device 40. The battery device 100 again corresponds in all other features to the one from Figure 3. Fig. 1. The spark device 40 differs in the functional design of a gas-permeable containment, or in other words, an open, gravimetric enclosure of the liquid volume 43. The spark device 40 comprises a reservoir 44 that is at least partially open and filled with liquid. The reservoir 44 essentially forms a basin bounded at the bottom and sides, or a section lowered relative to the rest of the discharge channel 30. A flow cross-section Q, lowered compared to adjacent sections of the discharge channel 30 and, in the illustrated embodiment, also reduced, is arranged below a fill level of the liquid volume 43. Thus, upon entering and exiting via a free liquid surface of an immersion bath, the outgassing traverses the liquid volume 43 in the section X.The phenomena, such as a bubble column drawn through the liquid phase, as well as the functions and effects of the gas treatment on the solid phase and gas phase of the passing outgassing, are of course achieved in the same way as in previously described embodiments.

[0043] The illustrated setup is highly simplified. To ensure improved retention or containment of the liquid volume 43 in the partially open reservoir 44 in mobile system environments, the shown limiting walls and barriers of the reservoir 44 can be designed in a structure that is further closed towards the top and preferably labyrinthine, providing a flow path in the liquid phase for a gas stream.

[0044] Furthermore, in alternative embodiments, various elements from the exemplary embodiments described above can be combined to confine a liquid volume 43 in a spark trap device 40. For example, a diaphragm 41 can be combined with a valve 42 or with a reservoir 44. Likewise, a valve can be combined with a reservoir 44.

[0045] A liquid used for the liquid volume 43 is preferably a dielectric liquid, such as a silicone oil. Firstly, this has a higher boiling point, and secondly, in the event of a leak, for example due to an accident in a mobile application, there is no risk of a short circuit if the liquid enters the receiving chamber 21.

[0046] Fig.Figure 4 shows an embodiment of the battery storage device 100 with a modified inlet-side configuration of the discharge channel 30. The remaining features of the battery storage device 100 correspond to any of the preceding embodiments. In this embodiment, the discharge channel 30 is not in contact with the bottom surfaces of the cell casings 12, but rather encloses a lower section of each battery cell 10. The inlet openings 31 are thus not positioned opposite the outlet sections 13, but instead enclose a circumference of the cell casings 12 above the outlet sections 13 in a sealing arrangement. In other words, lower end sections of the battery cells 10 are received in the inlet openings 31 of the discharge channel 30.

[0047] In other embodiments not shown, the discharge channel 30 is not arranged below the battery cells 10 in the housing 20, as in the illustrated embodiments. The discharge channel 30 also does not need to utilize a wall of the housing 20 to confine its length, and need not be formed as an integral part of the housing 20. Alternatively, the discharge channel 30 can be arranged laterally or above the battery cells 10. Furthermore, the discharge channel 30 can alternatively be designed as a separate part that is inserted into the housing 20. The shape of the discharge channel can be varied, provided that the inlet openings 31 always correspond to the arrangement of the battery cells 10, and that the outlet opening 32 and the extension of the discharge path S of the discharge channel 30 always correspond to the surrounding dimensions of the housing 20.

[0048] In an alternative embodiment, the battery storage device 100 itself can be a modular battery pack composed of several battery modules, each containing multiple battery cells. In another alternative embodiment, the battery storage device 100 can be a battery module comprised of a plurality of battery modules within a battery pack. In this alternative embodiment, the discharge channel 30 can extend from the housing of a battery module, which is thus considered a partial housing of the battery pack, across further battery modules. Accordingly, the outlet opening 32 of the discharge channel 30 can be located outside the housing of a battery module, and in particular on a common housing of the battery pack. Likewise, several such battery modules can share a common discharge channel 30 and a common outlet opening 32.The battery pack can have one or more outlet openings 32, which do not correspond to the number of battery modules. Furthermore, a discharge channel structure can be provided that branches out from one outlet opening 32 into several, in particular one discharge channel 30 per battery module.

[0049] The preceding descriptions of the embodiments describe the present invention solely by way of example. Naturally, individual features of the embodiments can be freely combined with one another, provided this is technically feasible, without departing from the scope of the present invention. Reference symbol list 100 battery storage units 10 battery cells 12 cell mantle 13 Outflow section 20 cases 21 Admission Chamber 30 Drainage channel 31 Channel inlet opening 32 Channel outlet opening 33 Outlet valve 40 spark trap device 41 gas-permeable membrane 42 valve 43 fluid volume 44 Reservoir Q Flow cross-section S Discharge route X section of the route

Claims

[1] Battery storage (100) comprising at least one battery cell (10): a housing (20) with a receiving chamber (21) separated from a surrounding atmosphere, for receiving at least one battery cell (10); a discharge channel (30) with a discharge section (S) which is separated from the receiving chamber (21) for spatially separate discharge of outgassing from the at least one battery cell (10), furthermore with: at least one channel inlet opening (31) which is designed to direct towards the at least one battery cell (10) for introducing the outgassing from the at least one battery cell (10) into the discharge channel (30), a channel outlet opening (32) which is designed to face the surrounding atmosphere, for the discharge of outgassing from the housing (20) into the surrounding atmosphere, and a spark trap device (40) which is arranged between the at least one channel inlet opening (31) and the channel outlet opening (32) in the discharge section (S) of the discharge channel (30); characterized by , that The spark trap device (40) comprises a liquid volume (43) which is received in a section (X) of the discharge section (S) of the discharge channel (30), wherein the liquid volume (43) fills a flow cross-section (Q) to be passed through in the section (X), for immersive gas scrubbing of the outgassing as the liquid volume (43) flows through it. [2] Battery storage device (100) according to claim 1, wherein the spark trap device (40) comprises at least one gas-permeable membrane (41) in the flow cross-section (Q) for limiting the liquid volume (43) in the section (X) of the discharge path (S). [3] Battery storage device (100) according to claim 1 or 2, wherein the spark trap device (40) comprises at least one pressure-opening valve (42) in the flow cross-section (Q) for limiting the liquid volume (43) in the section (X) of the discharge path (S). [4] Battery storage (100) according to one of claims 1 to 3, wherein the spark trap device (40) comprises an open reservoir (44) in which the flow cross-section (Q) is arranged to be lowered, for a gravimetric incorporation of the liquid volume (43) into the section (X) of the discharge section (S). [5] Battery storage device (100) according to any one of claims 1 to 4, wherein the at least one battery cell (10) comprises a pressure-opening outflow section (13) for pressure-reducing outflow of the outgassing from the at least one battery cell (10). [6] Battery storage device (100) according to claim 5, wherein the outflow section (13) is formed in the form of a predetermined breaking point in a cell shell (12) of the at least one battery cell (10). [7] Battery storage device (100) according to claim 5, wherein the outflow section (13) is formed in the form of a pressure valve in the cell shell (12) of the at least one battery cell (10). [8] Battery storage device (100) according to one of claims 5 to 7, wherein the at least one inlet opening (31) of the discharge channel (30) is adjacent to the outlet section (13) of the at least one battery cell (10) and / or is in contact with the cell shell (12). [9] Battery storage device (100) according to any one of claims 5 to 7, wherein the at least one inlet opening (31) of the discharge channel (30) encloses the outlet section (13) of the at least one battery cell (13) and / or a circumference of the cell shell (12). [10] Battery storage device (100) according to one of claims 1 to 9, wherein a pressure-opening outlet valve (33) is arranged in the outlet opening (32) of the discharge channel (30). [11] Battery storage device (100) according to any one of claims 1 to 10, wherein the liquid volume (43) contains a dielectric liquid. [12] Device (40) for cooling and wet separation of solids from outgassing from a battery cell (10), comprising: a discharge channel (30) which can be connected to the battery cell (10) via fluid communication and has a defined discharge section (S) for the discharge of outgassing from the battery cell (10); characterized by a liquid volume (43) which is taken up in a section (X) of the discharge section (S) of the discharge channel (30), wherein the liquid volume (43) fills a flow cross-section (Q) to be passed through in the section (X), for an immersive gas scrubbing of the outgassing during the flow through the liquid volume (43). [13] Device (40) according to claim 12, comprising at least one gas-permeable membrane (41) in the flow cross-section (Q) for limiting the liquid volume (43) in the section (X) of the discharge section (S). [14] Device (40) according to claim 12 or 13, comprising at least one pressure-opening valve (42) in the flow cross-section (Q) for limiting the liquid volume (43) in the section (X) of the discharge section (S). [15] Device (40) according to one of claims 12 to 14, comprising an open reservoir (44) in which the flow cross-section (Q) is arranged to be lowered, for a gravimetric integration of the liquid volume (43) into the section (X) of the discharge section (S). [16] Device (40) according to any one of claims 12 to 15, wherein the liquid volume (43) contains a dielectric liquid. [17] Method for gas treatment of outgassing from a battery cell (10) comprising the step: - Discharge of the outgassing from the battery cell (10) along a discharge path (S) into a surrounding atmosphere; characterized by the step: - Immersive washing of the outgassing by means of a flow passage (X, Q) leading through a liquid volume (43), which passes the outgassing along the discharge path (S), for cooling and wet separation of solids of the outgassing. [18] Method for gas treatment according to claim 17 using the spark trap device (40) according to any one of claims 12 to 16.

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