Pressure relief device for a battery housing, a battery case and a vehicle battery

Abstract

The invention relates to a pressure relief device (3) for a battery housing (1) of a vehicle battery (10), comprising at least one pressure relief body (3.1) with a pressure relief membrane (4), wherein the pressure relief body (3.1) includes at least one flame arrestor (6) which is arranged inside the pressure relief body (3.1) and in front of the pressure relief membrane (4). The invention further relates to a battery housing (1) and a vehicle battery (10).

Description

[0001] The invention relates to a pressure relief device for a battery housing, a battery housing with such a pressure relief device and a vehicle battery.

[0002] Pressure relief devices are known from the prior art for use in the battery housing of a vehicle battery. These devices consist of a rupture element, for example a rupture disc with a rupture membrane. The rupture disc or membrane can rupture upon impact with a pressure wave, such as those that can occur in lithium-ion batteries, allowing a gas stream to escape from the compartment.

[0003] From DE 10 2012 102 468 A1, an explosion protection device for a system arranged in an enclosed space is known, which has a pressure relief element arranged in a boundary wall. In the event of an explosion within the space, the pressure relief element provides pressure relief by diverting a gas flow out of the space. An enclosure adjoins the boundary wall, and at least one flame filter is arranged within this enclosure. The enclosure is designed such that a gas flow exiting the pressure relief element is guided within the enclosure and passes through the flame filter.

[0004] The invention aims to provide a pressure relief device with integrated flame arrestor protection that is improved compared to the prior art, thus ensuring flameless pressure release. The invention also aims to provide an improved battery housing and an improved vehicle battery.

[0005] The problem is solved according to the invention by a pressure relief device having the features specified in claim 1, and by a battery housing having the features specified in claim 8, and by a vehicle battery having the features specified in claim 10.

[0006] Advantageous embodiments of the invention are the subject of the dependent claims.

[0007] The pressure relief device according to the invention for a battery housing of a vehicle battery comprises at least one pressure relief body with a pressure relief membrane, wherein the pressure relief body includes at least one flame arrestor, which is arranged within the pressure relief body and in front of the pressure relief membrane. The flame arrestor is arranged between the pressure relief membrane and the battery cell. The particle filter, the flame arrestor, and the pressure relief membrane can be arranged in a direction from the battery cell towards the housing opening.

[0008] By providing the pressure relief device according to the invention with a flame penetration protection device, a flame penetration protection arrangement can be formed in a simple and effective manner.

[0009] In the event that open flames form in a vehicle battery, especially within the battery casing, a conventional pressure relief device, such as a rupture disc, is not sufficient to prevent open flames from passing outwards (or inwards).

[0010] The present pressure relief device, due to the integration of a flame arrestor and its placement within the pressure relief body and in front of the pressure relief membrane, effectively prevents, and in particular halts, flame propagation, for example, in the event of a so-called TP event (thermal propagation). This describes a chain reaction that can be triggered by an overheated or damaged battery cell and can spread to neighboring cells. This can potentially lead to a fire or explosion.

[0011] The vehicle battery can, for example, be a solid-state battery for a motor vehicle that is at least partially electrically powered. The pressure relief device with flame arrestor according to the invention prevents or even avoids the possibility of an open flame originating in the solid-state battery escaping to the outside. With conventional pressure relief devices, pressure that builds up inside the vehicle battery can escape to the outside through the pressure diaphragm, and an open flame can also pass through.

[0012] In one possible design, the flame penetration protection is at least partially gas-permeable.

[0013] In another possible embodiment, the flame penetration protection is designed to be liquid-permeable, at least in sections.

[0014] By positioning the flame arrestor in front of the pressure diaphragm, a flow of gases, liquids, etc. is allowed, but flame penetration is prevented.

[0015] In one possible embodiment, the flame arrestor is formed, at least in sections, from thermally conductive material and / or metal strips and / or metal wires. The flame arrestor exhibits mechanical strength, high flame retardancy, and high thermal stability.

[0016] The flame barrier can, for example, have a grid structure. It can consist of narrow gaps or a fine mesh. It can also have a washboard-like structure. Upon contact with the flame, the flame barrier can transfer heat to the gap walls or the structure itself, slowing and / or even extinguishing the flame.

[0017] For example, the flameproof membrane can contain metal and / or ceramic components. The flameproof membrane can essentially be plate-like.

[0018] The flame protection can, for example, contain aluminum and / or aluminum wool, at least in sections.

[0019] One possible design involves using a rupture diaphragm as the pressure relief membrane. The pressure relief element is, for example, a disc, in particular a rupture disc.

[0020] Another possible embodiment provides that the pressure relief body has at least one pressure relief opening, the first end of which is covered by the pressure relief membrane. For example, the pressure relief body comprises at least one external pressure relief membrane and an internal flame arrestor.

[0021] In one possible embodiment, the pressure relief body comprises at least one particle filter, the particle filter being arranged in the region of a second opening end of the pressure relief opening. The flame arrestor is arranged, in particular, between the particle filter and the pressure relief membrane. The particle filter prevents the flame arrestor from becoming clogged with coarse particles. The pressure relief body has a receiving space defined by the particle filter and the pressure relief membrane. The flame arrestor is protected from external environmental influences because it is located within the receiving space of the pressure relief body. Additionally, the particle filter can prevent flammable and / or glowing particles from escaping through the pressure relief body.

[0022] The battery housing according to the invention for a vehicle battery comprises a housing interior and at least one housing wall bounding the housing interior with a housing opening and a pressure relief device arranged in the housing opening as described above.

[0023] In one possible embodiment, the pressure relief body is arranged in the housing opening in such a way that the pressure relief membrane is led outwards through the housing opening and the flame protection is arranged in the area of ​​the housing wall and / or in the housing interior, in particular in a dry room.

[0024] The pressure relief device according to the invention enables flameless pressure relief, thereby preventing the uncontrolled escape of open flames that could be generated by the flammability of the battery cell.

[0025] The vehicle battery according to the invention comprises at least one battery cell and a battery housing enclosing the battery cell, as described above. The vehicle battery can be a solid-state battery.

[0026] The pressure relief device with integrated flame protection function can form an explosion protection device.

[0027] The battery casing encloses at least one battery cell and serves as a protective housing against external influences. Furthermore, the battery casing can regulate the temperature of the battery cell, thus mitigating the risk of thermal breakdown. Thermal breakdown describes, in particular, the uncontrollable overheating of the battery cell, for example, due to an internal short circuit, overcharging, external heat exposure, and / or advanced aging of the battery cells. Such factors can lead to a chain reaction within a battery, a so-called thermal propagation, in which a thermal event spreads from one battery cell to neighboring cells or modules. During such an event, large amounts of energy are released, which can create overpressure inside the battery. This pressure can be released by the rupture of the pressure relief membrane.In so-called solid-state batteries, an open flame can develop inside the battery casing, which can then propagate unhindered through a conventional rupture disc to the outside. The pressure relief device according to the invention, with integrated flame propagation protection, prevents the propagation of open flames from or into the system in accordance with legal regulations.

[0028] Exemplary embodiments of the invention are explained in more detail below with reference to a drawing.

[0029] This shows: Fig. 1 a sectional view of a vehicle battery according to the invention, comprising a battery housing, at least one battery cell arranged in the battery housing and at least one pressure relief device with integrated flame protection function.

[0030] The only Fig.Figure 1 shows a vehicle battery 10 according to the invention, for example a so-called solid-state battery, comprising at least one battery housing 1, at least one battery cell 2 arranged in the battery housing 1 and a pressure relief device 3 with integrated flame protection function.

[0031] The vehicle battery 10 can be a lithium-ion battery or a so-called solid-state battery.

[0032] The battery cell 2 is enclosed by the battery housing 1. The battery housing 1 forms a closed interior space 1.1 in which the at least one battery cell 2 or more battery cells 2 are arranged. At least one of the housing walls 1.2, in particular a side housing wall 1.2 of the battery housing 1, comprises at least one housing opening 1.3 in which the pressure relief device 3 is arranged or received.

[0033] The pressure relief device 3 can be connected to the housing opening 1.3 by at least a material-fit, form-fit and / or force-fit connection. The pressure relief device 3 is fixed in position within the housing opening 1.3.

[0034] The battery housing 1 together with the pressure relief device 3 according to the invention serves in particular as a flame propagation protection device and / or explosion protection device to prevent the propagation of open flames FL in the event of thermal propagation.

[0035] The pressure relief device 3 can be a rupture disc. The pressure relief device 3 consists, from right to left, of at least one pressure relief membrane 4, a flame arrestor 6, and a particle filter 5.

[0036] One problem that has emerged in TP tests is the formation of flames FL in, for example, solid-state cells. During a TP event, the resulting overpressure PR in the battery housing 1 of lithium-ion cells is released by means of one or more conventional rupture discs. To prevent the resulting flammable gas mixture from igniting outside the vehicle battery 10, a particulate filter 5 can be positioned in front of the rupture membrane of the rupture disc. In solid-state cells, open flames FL can occur during a TP event. It must be ensured that these open flames FL cannot penetrate the housing wall 1.2. This is not permitted by law.

[0037] The pressure relief device 3 according to the invention is designed to prevent an open flame FL, which may form in the interior of the housing 1.1 of the battery housing 1, from passing through to an outside or into an environment 11, for example a construction space.

[0038] The pressure relief device 3 comprises a pressure relief body 3.1. The pressure relief body 3.1 is, for example, a ring or a disc, in particular a rupture disc. The pressure relief body 3.1 comprises at least one pressure relief opening 3.2, for example, a through-opening. A first opening end 3.3 is completely covered by the pressure relief membrane 4. The particle filter 5 is arranged in the region of a second opening end 3.4 of the pressure relief opening 3.2.

[0039] For example, the pressure relief body 3.1 comprises at least one (with respect to the pressure relief opening 3.2) outer pressure relief membrane 4 and an inner flame arrestor 6, as well as an outer particle filter 5. With respect to the battery housing 1 and in the mounted state of the pressure relief device 3 on and / or in the battery housing 1, the pressure relief membrane 4 is located on the outside and the particle filter 5 and the flame arrestor 6 are located on the inside. "Outside" refers to an area outside the battery housing 1, for example, an environment 11. "Inside" refers to an area inside the battery housing 1, for example, the housing interior 1.1.

[0040] In the event of a TP (Torque Release) event, the pressure relief diaphragm 4 is designed to rupture and release any overpressure PR within the battery housing 1. The flame arrestor 6 is located between the pressure relief diaphragm 4 and the particle filter 5. The flame arrestor 6 prevents flames FL from escaping to the outside. The particle filter 5 traps coarse particles and prevents the flame arrestor 6 from becoming clogged. Under normal operating conditions, the flame arrestor 6 and the particle filter 5 are not exposed to environmental influences, as they are located behind the pressure relief diaphragm 4 inside the battery.

[0041] The pressure relief membrane 4 is located on the outer surface of the battery housing 1, ensuring that the interior 1.1 of the battery housing 1 is a so-called dry space. This dry space serves, for example, to protect the interior 1.1 from external environmental influences, such as excessive humidity. High humidity inside the battery can, for example, affect the chemical processes of charging and discharging the individual battery cells 2 and lead to corrosion of the electrodes and / or other metallic parts inside the housing 1.1. The dry space enables consistent charging and discharging performance, a long service life, and a high level of safety.

[0042] The pressure relief membrane 4 seals the dry chamber. This can be achieved, for example, by a special closure design in which the pressure relief opening 3.2 is hermetically sealed by the pressure relief membrane 4. The pressure relief device 3 is hermetically sealed in the housing opening 1.3 of the battery housing 1. Additionally, the battery housing 1 is gas-tight and liquid-tight to minimize the ingress of moisture.

[0043] The particle filter 5 is arranged on and / or in the area of ​​an inner surface of the housing wall 1.2 of the battery housing 1 and is thus located opposite the pressure relief membrane 4 in the dry chamber. The particle filter 5 can, for example, be designed as a sheet metal part, such as a stamped part. The particle filter 5 can be provided with a plurality of filter openings 5.1, for example, with elongated holes.

[0044] The flame arrestor 6 is located between the particle filter 5 and the pressure relief membrane 4 and within the pressure relief opening 3.2. The flame arrestor 6 is made, for example, of a highly thermally conductive material, such as aluminum, for example, aluminum wool. During thermal propagation, i.e., the uncontrolled overheating of battery cells 2, a high overpressure PR is generated in the housing interior 1.1 due to large amounts of released energy. This overpressure PR causes the pressure relief membrane 4 to burst, allowing the overpressure PR to escape. A flame FL can be contained by the flame arrestor 6. This prevents the flame FL from escaping from the housing interior 1.1.

[0045] The flame penetration protection 6 is designed to be air-permeable in order to allow a controlled bursting of the pressure relief membrane 4.

[0046] The flame arrestor 6 can, for example, have a grid structure. The flame arrestor 6 can consist of narrow gaps 6.1 and / or openings or a fine-mesh structure. The flame arrestor 6 can, for example, have a washboard-shaped structure. Upon contact with the flame FL, the flame arrestor 6 can transfer heat to the gap walls or to the structure and slow down and / or even extinguish the flame FL. Reference symbol list 1 battery case 1.1 Interior of the housing 1.2 Housing wall 1.3 Housing opening 2 battery cells 3 Pressure relief device 3.1 Pressure relief body 3.2 Pressure relief opening 3.3 End of opening 3.4 End of opening 4 Pressure relief membrane 5 particle filters 5.1 Filter opening 6 Flame penetration protection 6.1 Column 10 Vehicle battery 11 Environment FL Flame PR overpressure QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2012 102 468 A1

[0003]

Claims

[1] Pressure relief device (3) for a battery housing (1) of a vehicle battery (10), comprising at least one pressure relief body (3.1) with a pressure relief membrane (4), characterized by , that the pressure relief body (3.1) includes at least one flame arrestor (6) which is located inside the pressure relief body (3.1) and in front of the pressure relief diaphragm (4). [2] Pressure relief device (3) according to claim 1, characterized by , that the flame protection (6) is designed to be at least partially permeable to gas and / or liquid. [3] Pressure relief device (3) according to claim 1 or 2, characterized by , that the flame protection (6) is formed at least in sections from thermally conductive material and / or from metal strips and / or from metal wires. [4] Pressure relief device (3) according to one of claims 1 to 3, characterized by, that the pressure relief membrane (4) is a burst membrane. [5] Pressure relief device (3) according to any one of claims 1 to 4, characterized by , that the pressure relief body (3.1) has at least one pressure relief opening (3.2) whose first opening end (3.3) is covered by the pressure relief membrane (4). [6] Pressure relief device (3) according to claim 5, characterized by , that the pressure relief body (3.1) comprises at least one particle filter (5), wherein the particle filter (5) is arranged in the area of ​​a second opening end (3.4) of the pressure relief opening (3.2). [7] Pressure relief device (3) according to claim 6, characterized by , that the flame arrestor (6) is arranged between the particle filter (5) and the pressure relief membrane (4) within the pressure relief opening (3.2). [8] Battery housing (1) for a vehicle battery (10), comprising a housing interior (1.1) and at least one housing wall (1.2) defining the housing interior (1.1) with a housing opening (1.3) and a pressure relief device (3) arranged in the housing opening (1.3) according to one of the preceding claims 1 to 7. [9] Battery housing (1) according to claim 8, characterized by , that the pressure relief body (3.1) is arranged in the housing opening (1.3) such that the pressure relief membrane (4) is led outwards through the housing opening (1.3) and the flame arrestor (6) is arranged in the area of ​​the housing wall (1.2) and / or in the housing interior (1.1). [10] Vehicle battery (10) comprising at least one battery cell (2) and a battery housing (1) enclosing the battery cell (2) according to one of claims 8 to 9.

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