Degassing device for a traction battery of an electrically or partially electrically powered motor vehicle

Abstract

The present invention relates to a degassing device (20), a traction battery, and an electrically or partially electrically powered motor vehicle. The degassing device (20) has an inlet opening (21) and an outlet opening (22), wherein a flow path (23) extends between the inlet opening (21) and the outlet opening (22), wherein the inlet opening (21) is fluid-tightly closed by a bursting element (24), wherein the degassing device (20) has a spring-loaded check valve (25), wherein the check valve (25) is reversibly deflectable from a closed position, wherein the deflection of the check valve (25) from the closed position occurs against the spring force, such thatthat when a limit overpressure is exceeded in a region of the flow path (23) bounded by the bursting element (24) and the check valve, relative to an ambient pressure prevailing outside the traction battery (1), the check valve (25) is deflected from the closed position, wherein the degassing device (20) has a sensor device (26), wherein the sensor device (26) is arranged in the region of the flow path (23) bounded by the bursting element (24) and the check valve and is configured to detect degassing of one of the battery cells via the degassing opening based on the properties of the medium located in this region of the flow path (23).

Description

The present invention relates to a degassing device for a traction battery of an electrically or partially electrically powered motor vehicle. The invention further relates to a traction battery and an electrically or partially electrically powered motor vehicle. Degassing devices for traction batteries of electrically or partially electrically powered vehicles are generally known in the art. During operation of the traction battery, the interaction of various chemical mechanisms can lead to a significant increase in temperature and pressure within the battery cells. For example, overcharging, deep discharging, overloading, internally or externally caused overheating, or an internal cell defect can result in sometimes violent exothermic reactions, leading to the evaporation of the electrolyte present in the battery cells and its decomposition into other products. In particular, a variety of hazardous and / or flammable gases are formed, e.g., CO, CO2, ethene, H2, HF. Furthermore, vapors, liquids, and particles escape from the traction battery cells at high pressure and a high temperature of approximately 600°C.The components exiting the battery cells into the interior of the housing flow from the battery cells to a degassing device located on the battery housing. This device allows the gases, liquids, and particles to escape from the housing interior into the external environment. The liquids and particles are carried along in the hot gas. The degassing opening is typically sealed with a closure element, such as a bursting element. During normal operation, this element seals the housing interior against the external environment. When a battery cell degasses, for example, due to a pressure increase within the housing associated with degassing, the bursting element opens when a predefined overpressure is exceeded, allowing the released gas to escape from the housing interior through the degassing opening. DE 10 2022 205 778 A1 discloses a battery housing and a battery system comprising this housing for a motor vehicle. The battery housing has a housing body, the housing body having a vent opening that connects an interior of the housing body with the surrounding environment. Furthermore, the battery housing has a pressure relief valve arranged in the vent opening and configured to close it. The pressure relief valve is designed to open in the event of a pressure exceeding a limit value inside the housing body, thereby allowing the expulsion of a medium from the interior into the surrounding environment. WO 2021 / 116180 A1, DE 10 2022 119 112 A1, DE 10 2021 134 115 A1, DE 10 2021 200 672 A1, EP 4 297 165 A1 and WO 2021 / 001107 A1 disclose further state of the art. Typically, the traction battery is equipped with sensor devices designed to detect degassing. For example, DE 10 2022 205 778 A1 provides a temperature sensor designed to detect the temperature of a flowing medium. The temperature sensor is located adjacent to the vent. Typically, when degassing is detected, one or more control devices initiate corrective actions. These actions may include, for example, unlocking door locks and / or even opening vehicle doors. For safety reasons, one or more control units and the sensor system are usually active even when vehicles are parked. This creates a risk that the sensor system may come into contact with a medium whose properties cause it to falsely detect degassing from the traction battery and initiate the aforementioned measures. In particular, there is a risk that individuals may deliberately expose the sensor system to a medium whose properties cause it to falsely detect degassing from the traction battery, for example, to gain access to the vehicle's interior. The object of the present invention is to create a traction battery that enables reliable and tamper-proof detection of degassing. This problem is solved by the subject matter of the independent claims. The dependent claims concern advantageous further developments. The degassing device according to the invention is a degassing device for a traction battery of an electrically or partially electrically powered motor vehicle. The traction battery of the motor vehicle has a housing with a degassing opening, wherein the degassing device can be arranged on the housing in the area of ​​the degassing opening, and in particular can be connected to the housing. The connection can be made, for example, by means of a material-bonded connection, such as by welding. The degassing device has an inlet opening and an outlet opening. A flow path extends between the inlet opening and the outlet opening, the inlet opening being fluid-tightly sealed by a bursting element, the bursting element being configured to burst through the degassing opening in the event of degassing of a battery cell of the traction battery, the degassing device having a spring-loaded check valve, the check valve being reversibly deflectable from a closed position, wherein in the closed position the check valve prevents fluid from flowing through the flow path and when deflected from the open position the check valve allows fluid to flow through the flow path, wherein deflection of the check valve from the closed position occurs against the spring force of the spring-loaded check valve, such thatthat when a limit overpressure is exceeded in a region of the flow path bounded by the bursting element and the check valve compared to an ambient pressure prevailing outside the traction battery, the check valve is deflected from the closed position, wherein the degassing device has a sensor device, wherein the sensor device is arranged in the region of the flow path bounded by the bursting element and the check valve and is configured to detect degassing of one of the battery cells via the degassing port based on the properties of the medium located in this region of the flow path. Because the flow path to the sensor is closed off at the outlet side by the check valve when no degassing of the battery cells occurs via the degassing port, the sensor is sealed off from the traction battery environment. This prevents any intentional or unintentional manipulation of the sensor by gas or fluid flowing from the environment to the sensor. This, in turn, prevents false triggering of the sensor.Furthermore, the arrangement of the sensor device in the flow path of the degassing device has also proven advantageous in that even with small leaks of gas or other fluids through the bursting element, these substances can be reliably detected by means of the sensor device, since these substances accumulate in the flow path because they cannot escape through the outlet opening when the pressure in the flow path is below the limit overpressure. It is considered particularly advantageous if the sensor device has at least one of the following sensors: - a pressure sensor, - a temperature sensor, - a gas sensor, wherein the gas sensor is sensitive to a substance that is present in a gas mixture escaping from the battery cell during thermal runaway of the battery cell. In a preferred embodiment, it is provided that the flow path is sealed against the interior of the housing when the bursting element is intact, and that the flow path is sealed against the environment of the traction battery when the check valve is in the closed position. The check valve may well contain a mechanical spring. It is considered particularly advantageous if the bursting element has a bursting membrane. In an advantageous further development, the bursting element is designed to burst when a limit pressure is exceeded in a receiving chamber of the housing into which the degassing port opens. In this context, it is quite conceivable that the limit pressure of the bursting element is below the limit overpressure of the check valve, so that, despite any expansion of the gas in the flow path and a corresponding pressure drop of the gas mixture upon entering the flow path, the check valve is still reliably and immediately deflected from the closed position, thus enabling the fluid flowing into the flow path to escape from the outlet port as quickly as possible. It is considered particularly advantageous if the bursting element is designed to melt and burst when a limit temperature is exceeded. In a preferred embodiment, the bursting element is designed such that the inlet opening remains permanently open when the bursting element has burst. The traction battery according to the invention is preferably used in an electrically or partially electrically powered motor vehicle. It is provided that the traction battery has a housing, wherein the housing has a receiving space and battery cells received in the receiving space, wherein the housing has a degassing opening, and wherein a degassing device according to one of the preceding claims is arranged in the region of the degassing opening on the housing. Since the degassing device according to the invention is used in the traction battery according to the invention, the explanations regarding the advantages and advantageous further developments of the degassing device apply accordingly to the traction battery and vice versa. In a further advantageous embodiment, the degassing device is attached to the housing. This attachment can be achieved, for example, via a material-bonded connection, such as welding. It is considered particularly advantageous if the traction battery is designed as an immersion-cooled traction battery, such that the receiving chamber is circulated with a dielectric coolant during operation. In particular, with an immersion-cooled traction battery, it is considered especially advantageous that, due to the check valve, the flow path is closed again after any degassing when the limit overpressure is undershot, as the check valve then switches to the closed position, thus preventing leakage of dielectric coolant or escape of the dielectric coolant from the battery's receiving chamber. The motor vehicle according to the invention is an electrically or partially electrically powered motor vehicle. The motor vehicle includes the traction battery according to the invention. Accordingly, the descriptions of the advantages and advantageous further developments of the traction battery apply analogously to the motor vehicle and vice versa.It is provided that the motor vehicle has a control unit, wherein the sensor device is connected to the control unit via a signal connection, wherein the sensor device is configured to transmit a warning signal to the control unit upon detection of degassing of one of the battery cells via the degassing opening, wherein the control unit is configured, upon receipt of the warning signal, to cause one or more components of the motor vehicle to emit an optical and / or acoustic warning signal, and / or to open a door lock of one or more motor vehicle doors and / or to open one or more motor vehicle doors. The invention is explained in more detail in the following figures with reference to an exemplary embodiment, without being limited to this embodiment. The figures show: Fig. 1 a traction battery in a view according to arrow I in Fig. 2 in a schematic representation, Fig. 2 the traction battery in a view according to arrow II in Fig. 1, Fig. 3 a degassing device attached to the traction battery according to Fig. 1 in a view according to arrow III in Fig. 4, Fig. 4 the degassing device in a view according to arrow IV in Fig. 3, Fig. 5 the degassing device in a view according to arrow V in Fig. 4, Fig. 6 a motor vehicle with a traction battery according to Fig. 1. Figures 1 and 2 show a schematic representation of a traction battery 1 for an electrically or partially electrically powered motor vehicle 40. The traction battery 1 has a housing 10, the housing 10 enclosing a receiving space for battery cells. The housing 10 has a degassing opening, and a degassing device 20 is arranged in the area of ​​the degassing opening on the housing 10, namely, it is welded to the housing 10 in this area. The degassing device 20 is shown schematically in Figures 3, 4 to 5. The degassing device 20 has an inlet opening 21 and an outlet opening 22, wherein a straight flow path 23 is formed between the inlet opening 21 and the outlet opening 22, fluidically connecting the inlet opening 21 to the outlet opening 22. The inlet opening 21 is fluid-tightly sealed by a bursting element 24. The bursting element 24 is designed to burst through the degassing opening of the housing 10 in the event of degassing of a battery cell of the traction battery 1, thus allowing gas to escape from the receiving space of the housing 10 and thereby reducing the pressure. The bursting element 24 is designed to burst when a limit pressure is exceeded in the receiving space of the housing 10, into which the degassing opening opens. Furthermore, the degassing device 20 has a check valve 25 spring-loaded by a return spring 252, wherein the check valve 25 can be reversibly deflected from a closed position. In the closed position of the check valve 25, which is shown schematically in Fig. 4, the check valve 20, specifically by a sealing cap 251 of the check valve 25, prevents fluid from flowing through the flow path 23. The check valve 25 can be deflected from the open position against the spring force of the return spring 252. In the deflected state of the check valve 25 or the sealing cap 251 relative to the open position, fluid can flow through the flow path 23.The check valve 25 is designed to be deflected from the closed position against the spring force when a limit overpressure is exceeded in the flow path 23 compared to an ambient pressure prevailing outside the traction battery 1. The degassing device 20 includes a sensor device 26, the sensor device 26 being arranged in the flow path 23 between the bursting element 24 and the check valve 25. The sensor device 26 is configured to detect degassing of one of the battery cells via the degassing opening based on the properties of the medium located in the flow path 23. The flow of fluid from the receiving chamber of the housing 10 through the degassing opening and through the subsequent degassing device 20 in the event of degassing of one of the battery cells is schematically indicated by the arrows 30 in Fig. 2. The sensor device 26 is connected via a cable 27 leading into the interior of the housing 10 to a battery management system, which is not shown in detail. The battery management system is in turn connected via a signal to a control unit 41 of the motor vehicle 40, as shown schematically in Fig. 6. The control unit 41 is configured to receive a warning signal issued by the sensor device 26 when it detects degassing from one of the battery cells via the degassing port. Upon receiving the warning signal, the control unit 41 activates one or more components of the motor vehicle 40 such that these components issue a visual and / or audible warning signal. Furthermore, the control unit 41 is configured to open a door lock of one or more doors 42 of the motor vehicle 40 upon receiving the warning signal. Reference symbol list 1 Traction battery 10 Housing 20 Degassing device 21 Inlet opening 22 Outlet opening 23 Flow path 24 Burst element 25 Check valve 26 Sensor device 27 Wiring 30 Arrow 40 Motor vehicle 41 Control device 42 Motor vehicle door 251 Cover 252 Return spring QUOTES INCLUDED IN THE DESCRIPTION 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 DE 10 2022 205 778 A1 [0003, 0005]WO 2021 / 116180 A1

[0004] DE 10 2022 119 112 A1

[0004] DE 10 2021 134 115 A1

[0004] DE 10 2021 200 672 A1

[0004] EP 4 297 165 A1

[0004] WO 2021 / 001107 A1

[0004]

Claims

Degassing device (20) for a traction battery (1) of an electrically or partially electrically powered motor vehicle (40), wherein the traction battery (1) has a housing (10) with a degassing opening, wherein the degassing device (20) can be arranged on the housing (10) in the region of the degassing opening, wherein the degassing device (20) has an inlet opening (21) and an outlet opening (22), wherein a flow path (23) extends between the inlet opening (21) and the outlet opening (22), wherein the inlet opening (21) is fluid-tightly closed with a bursting element (24), wherein the bursting element (24) is configured to burst through the degassing opening in the event of degassing of a battery cell of the traction battery (1), wherein the degassing device (20) has a spring-loaded check valve (25), wherein the check valve (25) is reversible can be deflected from a closed positionwherein in the closed position the check valve (25) prevents the flow of fluid through the flow path (23) and, when the check valve is deflected from the open position, allows the flow of fluid through the flow path (23), wherein the check valve (25) deflects from the closed position against the spring force, such that when a limit overpressure is exceeded in a region of the flow path (23) bounded by the bursting element (24) and the check valve relative to an ambient pressure prevailing outside the traction battery (1), the check valve (25) is deflected from the closed position, wherein the degassing device (20) has a sensor device (26), wherein the sensor device (26) is arranged in the region of the flow path (23) bounded by the bursting element (24) and the check valve and is configured tobased on the properties of the medium located in this area of ​​the flow path (23) to detect degassing of one of the battery cells via the degassing opening. Degassing device (20) according to claim 1, wherein the sensor device (26) has at least one of the following sensors: - a pressure sensor, - a temperature sensor, - a gas sensor, wherein the gas sensor is sensitive to a substance that is present in a gas mixture escaping from the battery cell, which escapes from the battery cell during thermal runaway. Degassing device (20) according to claim 1 or 2, wherein the flow path (23) is sealed against the interior of the housing (10) when the bursting element (24) is intact, and wherein the flow path (23) is sealed against the environment of the traction battery (1) when the check valve is in the closed position. Degassing device (20) according to one of claims 1 to 3, wherein the bursting element (24) comprises a bursting membrane. Degassing device (20) according to one of claims 1 to 4, wherein the bursting element (24) is configured to burst when a limit pressure is exceeded in a receiving chamber of the housing (10) into which the degassing opening opens. Degassing device (20) according to one of claims 1 to 5, wherein the bursting element (24) is designed such that when the bursting element (24) bursts, the inlet opening (21) remains permanently open. Traction battery (1) of an electrically or partially electrically powered motor vehicle (40), wherein the traction battery (1) has a housing (10), wherein the housing (10) has a receiving space and battery cells received in the receiving space, wherein the housing (10) has a degassing opening, wherein a degassing device (20) according to one of the preceding claims is arranged in the area of ​​the degassing opening on the housing (10). Traction battery (1) according to claim 7, wherein the degassing device (20) is attached to the housing (10). Traction battery (1) according to claim 7 or claim 8, wherein the traction battery (1) is designed as an immersion-cooled traction battery, such that the receiving space is supplied with a dielectric coolant during operation of the traction battery (1). Motor vehicle (40), wherein the motor vehicle (40) is designed as an electrically or partially electrically powered motor vehicle, wherein the motor vehicle (40) has a traction battery (1) according to one of claims 7 to 9, wherein the motor vehicle (40) has a control unit (41), wherein the sensor unit (26) is connected to the control unit (41) via a signal connection, wherein the sensor unit (41) is configured to transmit a warning signal to the control unit (41) upon detection of outgassing of one of the battery cells via the outgassing opening, wherein the control unit (41) is configured, upon receipt of the warning signal, to cause one or more components of the motor vehicle (40) to emit an optical and / or acoustic warning signal, and / or to open a door lock of one or more motor vehicle doors (42) of the motor vehicle (40), and / or to open one or more motor vehicle doors (42) of the motor vehicle (40).

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