High-voltage battery with a sealing system arranged in a degassing opening

Abstract

The invention relates to a high-voltage battery for an electrically or partially electrically powered vehicle. The high-voltage battery comprises a closure system (4) arranged in a degassing opening of a battery module housing (1), wherein the closure system (4) has a sealing sleeve (5) and a sealing plug (6), wherein the sealing sleeve (5) is made of an elastically deformable material, wherein the sealing sleeve (5) has a first end facing a battery cell (2), a second end facing away from the battery cell (2), and a passage channel (7) extending from the first end to the second end, wherein a circumferential wall of the sealing sleeve (5) circumferentially delimits the passage channel (7) of the sealing sleeve (5), wherein the sealing sleeve (5) penetrates the degassing opening in the axial direction (Z) and abuts a cell housing of the battery cell (2) with its first end in a sealing manner, such thatthat a safety valve (3) of the battery cell (2) opens into the through-channel (8) to form a degassing channel from the safety valve (3) to the degassing opening, wherein the sealing plug (6) has a cover section (8) that closes the through-channel (7) of the sealing sleeve (5).

Description

[0001] The invention relates to a high-voltage battery for an electrically or partially electrically powered vehicle, in particular for an electrically or partially electrically powered passenger car.

[0002] In electric or partially electric vehicles, numerous battery cells are connected together to form a high-voltage battery, also known as a traction battery. Such a high-voltage battery typically consists of several hundred, sometimes up to several thousand, battery cells. Malfunctions can cause a battery cell to overheat, causing its electrolyte to transform into a gaseous state, which causes the pressure within the battery cell to rise sharply within a short period of time. To prevent an uncontrolled rupture of a cell casing or shell of the affected battery cell, battery cells are known to be equipped with a safety valve that opens at a predetermined internal cell pressure and allows the evaporated electrolyte and any other decomposition products formed to escape. Such a process is also known as degassing.The safety valve can be formed by an opening in a cell housing which is closed with a rupture disc which bursts at a defined bursting pressure and thus releases the valve opening.

[0003] The battery cells are often arranged in a housing enclosing the battery cells, such as a battery module housing, for protection against external influences and / or for the purpose of direct cooling of the battery cells. In a design with a housing enclosing the battery cells, it is necessary to discharge the gases escaping from a battery cell's safety valve from this housing in a controlled manner, particularly to prevent damage to the other battery cells arranged in the housing from the escaping hot gases. Such a housing typically has one or more vents for this purpose. These vents must, in turn, be reliably sealed against water, dirt, and salt.

[0004] DE 10 2021 001 258 A1 discloses a vent valve arranged at a vent opening of a battery housing. The vent valve comprises a support member connected to the battery housing and a cover connected to the support member and detachable under a predefined load. The cover is connected to the support member in such a way that the cover closes the vent opening in the normal state and releases when a predefined internal pressure in the battery housing is exceeded, allowing degassing.

[0005] US 2022 / 0 166 103 A1 discloses a high-voltage battery having the features of the preamble of patent claim 1.

[0006] Particularly in directly cooled battery cells, where a dielectric cooling fluid flows through the battery module housing, the venting opening must be reliably sealed against the environment. The permanent and secure connection of such a venting opening to the safety valve of the respective battery cell is problematic. Firstly, there is the problem that battery cells, for example prismatic battery cells or pouch cells, are subject to changes in their thickness during charging and discharging, also known as breathing. Furthermore, battery cells can experience aging-related swelling. This means that the battery cells expand with increasing service life. Such changes in the battery cells can lead to a change in the distance between the battery cell and the venting opening.Excessive mechanical impacts on the cell casing, such as those that could occur with a rigid connection of the safety valves to the vent opening, should also be avoided. Furthermore, in directly cooled battery cells, contact of hot gas with the dielectric cooling fluid should be avoided, as should leakage of cooling fluid to the outside and the ingress of foreign substances, such as water, into the cooling fluid. The ingress of foreign substances into the vent path from the safety valve to the vent opening should also be prevented.

[0007] The object of the present invention is to further develop a high-voltage battery having the features of the preamble of patent claim 1 in such a way that a safety valve of a battery cell is reliably connected to a degassing opening of a battery module housing accommodating the battery cell, in particular in such a way that the production of the connection is simplified and advantageously an extremely tight connection is nevertheless realized.

[0008] This problem is solved by a high-voltage battery having the features of patent claim 1. Advantageous further developments are the subject of the dependent claims.

[0009] The high-voltage battery according to the invention is intended for use in an electrically or at least partially electrically powered motor vehicle. The high-voltage battery comprises a battery module housing and at least one battery cell accommodated in the battery module housing. The battery cell comprises a cell housing with a safety valve for degassing the battery cell. The battery module housing has a housing wall with a degassing opening located opposite the safety valve in an axial direction. The high-voltage battery comprises a closure system arranged in the degassing opening. The closure system comprises a sealing sleeve and a closure plug. The sealing sleeve is made of an elastically deformable material. The sealing sleeve has a first end facing the battery cell, a second end facing away from the battery cell, and a through-channel extending from the first end to the second end.wherein a circumferential wall of the sealing sleeve circumferentially delimits the through-channel of the sealing sleeve, wherein the sealing sleeve penetrates the venting opening in the axial direction and bears sealingly with its first end against the cell housing of the battery cell, such that the safety valve opens into the through-channel to form a venting channel from the safety valve to the venting opening, wherein the wall of the sealing sleeve, with its outer circumferential surface, bears sealingly against an inner circumferential surface of the housing wall of the battery module housing that delimits the venting opening, wherein the sealing plug is inserted into the sealing sleeve from the second end of the sealing sleeve, wherein the sealing plug has a cover portion that closes the through-channel of the sealing sleeve, and wherein the sealing plug has a circumferential wall extending from the cover portion in the direction of the battery cell,wherein an outer peripheral surface of the circumferential wall of the sealing plug rests against an inner peripheral surface of the wall of the sealing sleeve and thereby supports the wall of the sealing sleeve radially inwards.

[0010] This design of the high-voltage battery easily creates a venting channel between the venting opening of the battery module housing and the battery cell's safety valve. Since the first axial end of the sealing sleeve forms a seal against the cell housing, it is ensured that the venting channel between the safety valve and the venting opening is sealed off from the rest of the battery module housing's interior. This ensures that substances located in the battery module housing's interior, such as a dielectric cooling fluid, cannot penetrate into the area of ​​the venting channel or the passageway of the sealing sleeve, thus protecting the safety valve, in particular, from contact with these substances.Secondly, this tight connection also ensures that in the event of a thermal event, gas escaping from the safety valve is directed towards the venting opening of the battery module housing and out of this opening. In particular, the tight connection of the first axial end of the sealing sleeve to the cell housing ensures that the gas escaping from the safety valve does not flow into the adjacent housing interior or at most flows into the housing interior in smaller quantities. This design ensures that at least a large portion of the gas escaping from the safety valve flows out reliably and directly from the venting opening of the battery module housing and is thus guided out of the battery module housing.

[0011] In principle, it is conceivable for the sealing sleeve to be designed such that it encloses the safety valves of adjacent battery cells, so that one and the same sealing sleeve forms a common venting channel for a plurality of safety valves. In this context, it is considered particularly advantageous if the sealing sleeve and the sealing plug are elongated, for example, in the shape of a rectangle with rounded corners.

[0012] A further advantage of the inventive design is that the sealing system can be installed in the venting opening particularly easily. For example, in a first step, the sealing sleeve can be inserted into the venting opening from an outer side of the battery module housing facing away from the battery cell, such that the axial first end rests against the cell housing of the battery cell. Subsequently, the closure plug can be inserted into the sealing sleeve from the same side to clamp the sealing sleeve in the venting opening by pressing the wall of the closure plug against the inner circumferential surface of the venting opening.

[0013] With regard to a good seal of the outer side of the wall of the sealing sleeve against the housing wall, it is considered advantageous if the wall of the sealing sleeve has one or more sealing lips on its outer peripheral surface.

[0014] The sealing contact between the outer peripheral surface of the sealing sleeve and the inner peripheral surface of the housing wall prevents the penetration of substances such as water or dirt from the environment into the interior of the battery module housing. Furthermore, in a directly cooled battery module, in which a dielectric fluid flows through the interior of the battery module housing, leakage of the dielectric fluid through the vent opening is prevented.

[0015] In a particularly preferred embodiment, the sealing plug is made of a harder material than the sealing sleeve.

[0016] It is considered particularly advantageous if the wall of the sealing sleeve has, at its first end, a circumferential retaining section that projects radially outward relative to the adjacent section of the wall, wherein the retaining section engages behind the housing wall on an inner side facing the battery cell. This design has the advantage that the sealing sleeve is still securely held in the venting opening even if the sealing plug is detached. Such detachment occurs in particular when the pressure in the passageway increases due to gases escaping from the safety valve. Such detachment is desirable in order to open the venting channel.During such an event, the sealing sleeve's sealing effect is still sufficiently ensured, at least temporarily, because the pressure prevailing in the passageway ensures that the sealing sleeve, especially the wall, is still pressed sufficiently strongly against the remaining sealing surfaces of the other components, such as the housing wall and the cell housing. The retaining section increases the positional stability of the sealing sleeve in the vent opening, especially if the sealing plug has been removed from the sealing sleeve.

[0017] In a particularly preferred embodiment, the wall of the sealing sleeve has a radially outwardly projecting circumferential support section at its end facing away from the battery cell. The support section bears against an outer side of the housing wall facing away from the battery cell, so that the interaction of the support section with the outer side of the housing wall prevents further insertion of the sealing sleeve into the vent opening. Such a design offers particular advantages when installing the closure system in the battery module housing and also leads to an increase in the sealing of the housing interior of the battery module housing against the environment.

[0018] It is considered particularly advantageous if the wall of the closure plug prevents deformation of the support section and / or deformation of the holding section radially inwards.

[0019] It is considered particularly advantageous if the closure system is designed such that when a predetermined limit pressure in the through-channel is exceeded, the closure plug is pushed completely out of the sealing sleeve to release the through-channel for gas flowing out of the safety valve of the battery cell. Thus, the closure plug is detachable from the sealing sleeve during degassing, preferably is shot out of it, in order to release the degassing channel as quickly and completely as possible. This design has the advantage that when the battery cell is degassed, the degassing opening or the through-channel is released as quickly as possible. Such a design with the closure plug being pushed out has particular advantages over closure systems in which a material must be melted through, since melting through usually takes a long time.

[0020] In a particularly preferred embodiment, the closure system consists exclusively of the sealing sleeve and the closure plug.

[0021] It is considered particularly advantageous in terms of ease of manufacture if the sealing plug is made of one plastic and the sealing sleeve is made of another plastic, the plastic of the sealing plug having a greater hardness than the plastic of the sealing sleeve.

[0022] Due to the fact that the sealing sleeve and the sealing plug form separate components, complex injection molding processes, such as two-component (2K) injection molding processes for producing a radially stiffened, one-piece sealing element, can be dispensed with.

[0023] Preferably, the sealing sleeve and the sealing plug are each formed as a single piece. The sealing sleeve and the sealing plug are preferably made of materials that are thermally stable with respect to the temperatures of any escaping gases, so that neither the sealing sleeve nor the sealing plug will melt during degassing.

[0024] It is considered particularly advantageous if the sealing plug and the sealing sleeve form separate components and can be completely separated from each other.

[0025] In a particularly preferred embodiment, it is provided that the battery module housing is flowed through by a dielectric cooling fluid in order to directly cool the at least one battery cell.

[0026] In a particularly preferred embodiment, it is provided that the wall of the sealing sleeve has a circumferential groove, wherein the wall of the sealing plug is inserted into this circumferential groove.

[0027] The following figures illustrate the invention in more detail using an exemplary embodiment, without being limited to this embodiment. They show: Fig. 1 a partial area of ​​a battery module in a schematic representation in a sectional view, Fig. 2 a closure system comprising a sealing sleeve and a closure plug inserted into the sealing sleeve, in a perspective view.

[0028] The Fig. Figure 1 shows a portion of a high-voltage battery for an electrically or at least partially electrically powered vehicle, namely a portion of a battery module. The battery module comprises a battery module housing 1, wherein a plurality of battery cells 2 are accommodated in the battery module housing 1. For reasons of clarity, Fig.1 only shows a battery cell 2 and a lower housing wall of the battery module housing 1. The battery cell 2 comprises a cell housing with a safety valve 3 for degassing the battery cell 2. The battery module housing 1 has a housing wall with a degassing opening opposite the safety valve 3 of the battery cell 2 in an axial direction Z. A closure system 4 is arranged in the degassing opening, wherein the closure system 4 consists of a sealing sleeve 5 and a closure plug 6. The sealing sleeve 5 consists of an elastically deformable material, wherein the sealing sleeve 5 has a first end facing the battery cell 2, which first end extends into the housing interior enclosed by the battery module housing 1 up to the battery cell 2.Furthermore, the sealing sleeve 5 has a second end opposite the first end, which accordingly faces away from the battery cell 2, wherein a through-channel 7 extends from the first end to the second end through the sealing sleeve 5. The through-channel 7 is circumferentially delimited by a circumferential wall of the sealing sleeve 5, wherein the first end and the second end form part of the wall. The sealing sleeve 5 is arranged in the venting opening such that the sealing sleeve 5 penetrates the venting opening in the axial direction Z, which is identical to a vehicle vertical direction Z, and the first end rests against the cell housing of the battery cell 2 such that the safety valve 3 opens into the through-channel 7 and is circumferentially enclosed in a sealing manner by the first end of the wall.The sealing sleeve 5 accordingly forms a venting channel from the safety valve 3 to the venting opening, wherein this venting channel is sealed from the environment, in particular from the interior of the battery module housing 1, so that no mass transfer can take place between the interior of the housing and the through-channel 7. In particular, the sealing sleeve 5 prevents any dielectric cooling fluid flowing in the interior of the housing from reaching the area of ​​the through-channel 7 of the sealing sleeve 5 and thus the safety valve 3. In order to prevent foreign substances from penetrating the through-channel 7 from the outside and thus to protect the safety valve 3 from external influences, the through-channel 7 is closed by means of the sealing plug 6, wherein the sealing plug 6 is inserted into the sealing sleeve 5 from the second end of the sealing sleeve 5.The closure plug 6 comprises a closed cover section 8, which closes the passage channel 7 of the sealing sleeve 5. The closure plug 6 has a circumferential wall 9 extending from the cover section 8, wherein an outer circumferential surface of the circumferential wall 9 of the closure plug 6 bears against an inner circumferential surface of the wall of the sealing sleeve 5, thereby supporting the wall of the sealing sleeve 5 radially inward and pressing it against the inner circumferential surface of the housing wall delimiting the venting opening.

[0029] The closure system, consisting of the sealing sleeve 5 and the sealing plug 6, is designed such that when a predetermined limit pressure in the passage 7 is exceeded, the sealing plug 6 is completely pushed out of the sealing sleeve 5, opening the passage 7 for gas flowing out of the safety valve 3 of the battery cell 2. In the event of a thermal event or degassing of the battery cell 2, the gas from the safety valve 3 will flow into the passage 7, and as soon as the limit pressure is exceeded, the sealing plug 6 is shot out, thus opening the passage 7, allowing the gas to flow out of the passage 7.

[0030] To stabilize the sealing sleeve 5 in the venting opening, it is provided that the wall of the sealing sleeve 5 has, at its first end, a circumferential holding section 10 projecting radially outward relative to the adjacent section of the wall, wherein the holding section 10 engages behind the housing wall on an inner side facing the battery cell 2. Furthermore, it is provided that the wall of the sealing sleeve 5 has, at its end facing away from the battery cell 2, a radially outward-projecting circumferential support section 11, wherein the support section 11 bears against an outer side of the housing wall facing away from the battery cell 2, so that further insertion of the sealing sleeve 5 into the venting opening is prevented by the interaction of the support section 11 with the outer side of the housing wall. List of reference symbols 1 battery module housing 2 battery cells 3 Safety valve 4 locking system 5 Sealing sleeve 6 sealing plugs 7 Through channel 8 Lid section 9 Wall 10 stopping section 11 Support section Z axial direction

Claims

[1] A high-voltage battery for an electrically or at least partially electrically powered vehicle, wherein the high-voltage battery comprises a battery module housing (1) and at least one battery cell (2) accommodated in the battery module housing (1), wherein the battery cell (2) comprises a cell housing with a safety valve (3) for degassing the battery cell (2), wherein the battery module housing (1) comprises a housing wall with a degassing opening opposite the safety valve (3) in an axial direction (Z), wherein the high-voltage battery comprises a closure system (4) arranged in the degassing opening, wherein the closure system (4) comprises a sealing sleeve (5), wherein the sealing sleeve (5) is made of an elastically deformable material, wherein the sealing sleeve (5) has a first end facing the battery cell (2), a second end facing away from the battery cell (2), and a through-channel (7) extending from the first end to the second end,wherein a circumferential wall of the sealing sleeve (5) circumferentially delimits the through-channel (7) of the sealing sleeve (5), wherein the sealing sleeve (5) passes through the degassing opening in the axial direction (Z) and bears sealingly with the first end against the cell housing of the battery cell (2), such that the safety valve (3) opens into the through-channel (8) to form a degassing channel from the safety valve (3) to the degassing opening, wherein the wall of the sealing sleeve (5) bears sealingly with its outer circumferential surface against an inner circumferential surface of the housing wall of the battery module housing (1) delimiting the degassing opening, , characterized byin that the closure system has a closure plug (6), wherein the closure plug (6) is inserted into the sealing sleeve (5) from the second end of the sealing sleeve (5), wherein the closure plug (6) has a cover section (8) which closes the through-channel (7) of the sealing sleeve (5), and wherein the closure plug (6) has a circumferential wall extending from the cover section (8) in the direction of the battery cell (2), wherein an outer circumferential surface of the circumferential wall of the closure plug (6) bears against an inner circumferential surface of the wall of the sealing sleeve (5) and thereby supports the wall of the sealing sleeve (5) radially inwards. [2] High-voltage battery according to claim 1, wherein the sealing plug (6) consists of a harder material than the sealing sleeve (5). [3] High-voltage battery according to claim 1 or 2, wherein the wall of the sealing sleeve (5) has at its first end a circumferential holding section (10) projecting radially outwardly relative to the adjacent section of the wall, wherein the holding section (10) engages behind the housing wall on an inner side facing the battery cell (2). [4] High-voltage battery according to one of claims 1 to 3, wherein the wall of the sealing sleeve (5) has, at its end facing away from the battery cell (2), a radially outwardly projecting circumferential support section (11), wherein the support section (11) bears against an outer side of the housing wall facing away from the battery cell (2), so that further insertion of the sealing sleeve (5) into the degassing opening is prevented by the interaction of the support section (11) with the outer side of the housing wall. [5] High-voltage battery according to claim 3 or 4, wherein the wall of the closure plug (6) prevents deformation of the holding section (10) and / or the support section (11) radially inward. [6] High-voltage battery according to one of claims 1 to 5, wherein the closure system (4) is designed such that when a predetermined limit pressure in the through-channel (7) is exceeded, the closure plug (6) is completely pressed out of the sealing sleeve (5) to release the through-channel (8) for gas flowing out of the safety valve (3) of the battery cell (2). [7] High-voltage battery according to one of claims 1 to 6, wherein the closure system (4) consists exclusively of the sealing sleeve (5) and the closure plug (6). [8] High-voltage battery according to one of claims 1 to 7, wherein the sealing plug (6) consists of a plastic and the sealing sleeve (5) consists of a different plastic, wherein the plastic of the sealing plug (6) has a greater hardness than the plastic of the sealing sleeve (5). [9] High-voltage battery according to one of claims 1 to 8, wherein the sealing plug (6) and the sealing sleeve (5) form separate components and are completely detachable from one another. [10] High-voltage battery according to one of claims 1 to 9, wherein the battery module housing (1) is flowed through by a dielectric cooling fluid in order to directly cool the at least one battery cell (2).

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