High-voltage battery for use in an electric or hybrid vehicle

Abstract

The invention relates to a high-voltage battery (10) for use in an electric or hybrid vehicle (100), comprising at least one battery cell (11) for storing electrical energy, a battery housing (12) for receiving the at least one battery cell (11), a cooling unit (13) with a cooling medium (14) for dissipating heat from the battery cell (11), and a degassing unit (20) with at least one degassing opening (21) for safely removing battery gas from the battery cell (11) from the battery housing (12), further comprising a particle separator (22) for separating liquid components of a mixture of the battery gas and the cooling medium (14) in the event of outgassing of the battery cell (11), wherein the particle separator (22) has a plurality of openings (22.1) through which at least the liquid components of the mixture can be discharged from the degassing unit (20).

Description

[0001] The invention relates to a high-voltage battery with the features of independent claim 1 and to an electric or hybrid vehicle with the features of independent claim 11.

[0002] High-voltage batteries are used in electric and hybrid vehicles to store electrical energy and supply it to an electric drive motor during vehicle operation. Since significant amounts of energy, often up to several dozen kilowatt-hours, and high electrical voltages of several hundred volts are required, a large number of battery cells are generally combined in a battery pack. Several such battery cells are grouped together in a battery module. The battery module may have a housing that encloses these multiple battery cells. Several such battery modules are, in turn, combined to form a battery pack and housed in a battery pack casing.

[0003] For example, malfunctions in the battery cells can occur due to defects in the charging or power electronics, or after a vehicle accident. Chemical reactions can take place within the affected cells, leading to a pressure increase inside the cell casing. In these exceptional cases (also known as thermal runaway), for example, due to overcharging or thermal overload, gas can be released from the inside of the battery cells. For a degassing event, where a single battery cell releases gas from its interior via an overpressure mechanism, for example, due to overcharging or thermal overload, a special space is provided in the battery pack casing. This space allows the released gas to expand, reducing its temperature and pressure. The gas is then released from the inside of the battery pack casing to the outside via a pressure relief device.

[0004] In such a case of degassing, a gas mixture toxic to humans can escape from the battery cell. In addition to toxic substances, this gas mixture can also contain flammable components, for example, in the form of combustible particles such as graphite dust. Hazards to people and materials due to escaping toxic and / or flammable gas mixtures must be minimized.

[0005] Cooling units containing a cooling medium are regularly used to cool high-voltage batteries. If this cooling unit is damaged in a previously described exceptional case, the cooling medium can mix with the battery gas, creating a gas mixture that can increase the aforementioned danger.

[0006] German patent application DE 10 2019 008 657 A1 discloses a high-voltage battery with a particle separator, which has a degassing unit with a particle separator, wherein the particle separator is designed as a single opening in the degassing unit. Solid particles of the battery gas are ejected through the single opening at the end of the degassing unit.

[0007] JP 2018 073 560 A discloses a high-voltage battery for a vehicle with a degassing unit. The degassing unit has valves through which the battery gas can escape in a controlled manner in exceptional cases. The degassing unit also includes a particle separator in the form of blocking elements, which separates solid particles from the gas and thus prevents, for example, graphite dust from being carried further.

[0008] DE 10 2022 110 532 A1 discloses a safety housing element for high-voltage storage devices in partially electrically powered vehicles, which prevents glowing particles from escaping from the hot gas-particle mixture by means of a swirl chamber with at least one connected particle collection chamber.

[0009] A disadvantage of the current state of the art is that, for example, liquid particles from the gas mixture of battery gas and cooling medium cannot be reliably separated and removed. This can create a gas mixture that is dangerous for the occupants, first responders, or other vehicle components.

[0010] It is therefore an object of the present invention to overcome at least one of the disadvantages described above, at least partially. In particular, it is an object of the invention to propose an improved, especially safety-related, high-voltage battery.

[0011] The foregoing problem is solved by a high-voltage battery with the features of independent claim 1 and by an electric or hybrid vehicle with the features of independent claim 11. Further features and details of the invention will become apparent from the dependent claims, the description, and the drawings. Features and details described in connection with the high-voltage battery according to the invention naturally also apply in connection with the electric or hybrid vehicle according to the invention, and vice versa, so that the disclosure regarding the individual aspects of the invention always refers, or can refer, to each other.

[0012] According to the invention, a high-voltage battery for use in an electric or hybrid vehicle is provided, comprising at least one battery cell for storing electrical energy, a battery housing for receiving the at least one battery cell, a cooling unit with a cooling medium for dissipating heat from the battery cell, and a degassing unit with at least one degassing opening for safely removing battery gas from the battery cell from the battery housing, further comprising a particle separator for separating liquid components of a mixture of the battery gas and the cooling medium in the event of outgassing from the battery cell, wherein the particle separator has a plurality of openings, whereby at least a part of the liquid components of the mixture, i.e. the separated liquid and / or solid components from the mixture, can be discharged from the degassing unit.The remaining gas can therefore escape from the battery essentially free of the components, especially liquid components, of the cooling medium.

[0013] The removal of gases from a high-voltage battery by means of a degassing unit according to the invention in the event of a risk of overheating is a critical aspect of safety management in electric vehicles, which ensures both the safety of the occupants and the performance of the battery.

[0014] Overheating can cause chemical reactions within the battery to produce gases, leading to a pressure buildup. If this pressure is not released in a controlled manner, it can result in an explosive battery failure, posing a danger to vehicle occupants and the surrounding environment. Another risk is thermal runaway, where the battery temperature rises uncontrollably, triggering a chain reaction. Gas release and temperature control can minimize this risk, thus enhancing vehicle safety. High-voltage batteries are typically equipped with safety mechanisms that activate in the event of overheating. Gas release is part of this safety strategy, designed to maintain battery integrity and prevent potential hazards. Overheating can not only pose safety risks but also negatively impact battery performance and lifespan.The effective removal of gases and the regulation of temperature keep the battery in an optimal operating condition, which extends its efficiency and lifespan.

[0015] A particular danger can arise from the mixture (emulsion) of battery gas and coolant. The risk of ignition is significantly increased, resulting in an explosive mixture that can lead to an explosion or fire. Combustion of such emulsions can also release toxic fumes that are harmful to health.

[0016] To reduce these hazards, a particle separator is proposed according to the invention, wherein the particle separator has a plurality of openings through which at least a large proportion of the liquid components of the mixture can be separated from the battery gas and discharged from the degassing unit. The particle separator is designed as a guide geometry or flow guide element for the battery gas and / or the mixture of battery gas and cooling medium, so that during the degassing of the battery cells, the mixture is guided along the particle separator. The geometry of the particle separator ensures that the volume flow of the gas or emulsion is influenced. In particular, the volume flow is guided in such a way that the liquid components flow in a defined direction and against a wall, are slowed down there, and then flow downwards due to gravity.To prevent the separated liquid components from mixing with the gas again, the openings according to the invention are provided. The openings allow the liquid components, which flow out of the degassing unit particularly due to gravity, to be drained or removed.

[0017] Before the emulsion or gas mixture can leave the battery casing, the liquid components are separated from the battery gas, thus reducing the risk of ignition and therefore a possible explosion.

[0018] In the context of the invention, openings are understood to be a plurality of recesses or bores through which at least liquid, and preferably also solid, components can flow out. The openings or recesses are preferably formed in a wall of the degassing unit or a channel. The degassing unit thus has at least one section through which the battery gas is introduced from the battery cells and at least one section, more precisely the degassing opening, through which the battery gas is discharged from the battery housing. In addition, the high-voltage battery according to the invention has further, distinct openings through which the liquid components are discharged from the degassing unit. Accordingly, these openings are preferably arranged on a side facing away from the battery cells.In particular, the openings for the liquid components are arranged in the flow path between the opening for introducing the battery gas and the degassing opening.

[0019] It is advantageous to include a particle collector, which can capture at least some of the liquid components of the mixture from the degassing unit. Consequently, the liquid components collected by the particle separator are directed through the openings into the particle collector and thus out of the degassing unit, allowing them to be stored in the particle collector and preventing them from returning to the degassing unit. The separated liquid components therefore cannot mix with the battery gas and form an explosive mixture. This further enhances safety.

[0020] Furthermore, it is conceivable that the degassing unit has at least one exhaust duct through which the battery gas expands, with the particle separator located at this duct. Excessive heat generation can lead to the decomposition of electrolyte and other materials within the battery, resulting in gas evolution. Once the pressure reaches a critical point, the pressure relief valves or rupture discs open to release the excess pressure. The released gases are then safely vented from the battery through the exhaust duct. Gas venting via the exhaust duct in electric or hybrid vehicles is crucial for ensuring the safety of vehicle occupants and minimizing the risk of battery fires or explosions. The gas is ultimately released into the environment. The exhaust duct is designed to direct the gases to an area that is harmless to occupants and sensitive vehicle components.

[0021] It is known that filters and adsorption materials can be used before the final exit from the vehicle to neutralize harmful components, e.g., graphite powder. According to the invention, the particle separator is used additionally or alternatively to separate at least or additionally liquid particles from the gas / gas mixture and then to separate them through the openings, thus making remixing with the battery gas more difficult or preventing it. For this purpose, the particle separator is arranged or designed on, and in particular within, the exhaust duct. This means that the particle separator is located in the battery gas flow and thus influences the flow. Consequently, the particle separator has a geometry that affects the flow of the gas mixture (emulsion).

[0022] Within the scope of the invention, the openings of the particle separator can advantageously be arranged in the wall of the exhaust duct, with the openings forming connecting channels between the exhaust duct and the particle collector. This means that the openings are arranged radially to the exhaust duct and thus to the volume flow of the gas / gas mixture. The openings are located in the wall of the exhaust duct. This means that the openings form connecting channels or passages for the liquid components, allowing these components to reliably enter the particle collector. The openings can, for example, be designed as holes, bores, or slots, or have an angular geometry. This ensures a reliable fluidic connection between the exhaust duct and the particle collector.

[0023] Advantageously, the exhaust duct can be designed as a cylindrical pipe. Pipes can be easily sealed to prevent leaks. This is particularly important when handling hazardous or toxic gases, such as those that can be generated in high-voltage batteries. Furthermore, the flow velocity and direction can be precisely controlled within pipes. This also facilitates the implementation of particle separators and / or pressure relief valves and / or filters.

[0024] It is also conceivable that the openings are arranged along the longitudinal axis of the exhaust duct. The longitudinal axis here refers to the direction of the gas / gas mixture flow. Thus, the openings are arranged along the exhaust duct, i.e., from an inlet opening for the gas from the battery cell or battery module towards the degassing opening, from which the gas is discharged from the battery / battery housing. Accordingly, on the path of the gas from the battery cell to the degassing opening, the liquid component of the gas / gas mixture can be discharged from the exhaust duct at a multitude of openings. Consequently, there is not a single opening at the outlet end of the exhaust duct, which creates the risk that some particles will not be reliably separated. Instead, there are multiple opportunities for the separation of liquid components from the mixture along the length of the exhaust duct.

[0025] According to the invention, the particle separator has a spiral guide element. The spiral geometry of the guide element causes the emulsion (mixture and combustion gases) to rotate; the liquid components, particularly the cooling medium, are accelerated radially outwards by the resulting centrifugal force due to their higher density compared to the combustion gas, where they strike the wall of the exhaust duct or pipe and are decelerated. The liquid components then flow downwards by gravity or out of the degassing unit, particularly the exhaust duct, through the openings. The rotating gas flow in the degassing unit, particularly the exhaust duct, enhances this effect.

[0026] The spiral guide element can be designed as a single piece or as a separate component.

[0027] According to the invention, the spiral-shaped guide element extends along a longitudinal axis of the exhaust duct.

[0028] The proposed particle separator with the spiral guide element offers an efficient method for separating particles, especially liquid components and battery gas in high-voltage batteries.

[0029] In contrast to existing technologies, the separator according to the invention uses a helical or spiral guide element that imparts an additional rotational movement to the particles and the gas. This rotational movement generates a centrifugal force that pushes the heavier particles outwards, while the lighter gas remains in the center. The centrifugal force enables a clear separation of particles and gas.

[0030] Within the scope of the invention, the spiral guide element can have a plurality of turns, with at least one opening being arranged between two successive turns. The special design of the separator reduces the pressure drop, resulting in more efficient operation. The particles can be easily discharged at the radial openings, and the cleaned gas can flow out unhindered. The exhaust gas channel is formed by a screw, i.e., the spiral guide element, particularly within a pipe. The combination of linear and rotary motion enables effective and energy-efficient particle separation in high-voltage batteries.

[0031] In other words, imagine a tornado that flings particles outwards while clean gas remains in the center. This effect is used in the described separator to separate the gas mixture and remove the liquid components from the exhaust duct.

[0032] The number of turns of the spiral guide element in the particle separator has a decisive influence on the separation performance.

[0033] More windings result in a higher centrifugal force and thus better separation of the particles from the gas. The design according to the invention ensures that the radially outwardly displaced particles are completely removed from the system, thereby achieving maximum separation efficiency.

[0034] The number of turns and the arrangement of the openings are crucial factors for the efficiency of the particle separator. Careful design of these parameters allows for optimal separation of particles and gas.

[0035] It is also conceivable that the cooling medium includes a heat transfer oil. Heat transfer oil is a specialized medium used in various heat transfer applications, particularly in cooling batteries in electric vehicles. It serves to efficiently dissipate and regulate the heat generated during battery operation. Unlike water, heat transfer oil has a higher thermal conductivity and can be used in a wider temperature range, making it an ideal choice for thermal management in electric vehicles. Heat transfer oils have a higher specific heat capacity than water, meaning they can store more heat without a significant temperature increase. This is particularly important for keeping battery temperatures within safe limits. By using heat transfer oil, the active cooling effort required while driving can be reduced.This has a positive impact on the electric vehicle's range, as less energy is required for cooling. Advanced heat transfer oils enable shorter charging times and higher power density. This leads to improved temperature management efficiency and reduces pumping losses, thus increasing the vehicle's overall performance. Overall, heat transfer oil plays a crucial role in the thermal management of electric vehicles by helping to cool the batteries efficiently and optimize performance. The design according to the invention then allows the gas to be discharged from the battery essentially free of the heat transfer oil.

[0036] The special design of the particle separator according to the invention enables effective and energy-efficient particle separation of the gas mixture of battery gas and heat transfer oil in, for example, a thermal runaway of a high-voltage battery, so that the liquid components of the gas mixture, i.e., the heat transfer oil, are separated again from the battery gas.

[0037] The above problem is further solved by an electric or hybrid vehicle according to the invention comprising a high-voltage battery according to any one of claims 1 to 10.

[0038] This results in the same advantages with regard to an electric or hybrid vehicle according to the invention as have already been described with regard to a high-voltage battery according to the invention.

[0039] Further advantages, features, and details of the invention will become apparent from the following description, in which a single embodiment of the invention is described in detail with reference to the drawings. The features mentioned in the claims and in the description can each be essential to the invention individually or in any combination. Fig. 1 schematically a possible embodiment of a high-voltage battery according to the invention, Fig. 2a a section of an exhaust duct according to the invention, Fig. 2b a sectional view of a Fig. 2a exhaust duct shown and Fig. 3 an electric or hybrid vehicle with a high-voltage battery according to the invention.

[0040] The figures use identical reference numerals for the same technical features, even for different embodiments.

[0041] In the Fig. Figure 1 shows a high-voltage battery 10 according to the invention for use in an electric or hybrid vehicle. The high-voltage battery 10 comprises a plurality of battery cells 11, which are grouped into two battery modules and arranged in a battery housing 12. A cooling unit 13 is provided in the battery modules for the battery cells 11, which cools the battery cells 11 by means of a cooling medium 14. In particular, a heat transfer oil is used as the cooling medium 14. It serves to efficiently dissipate and regulate the heat generated during the operation of the battery cells 11.

[0042] The high-voltage battery 10 further comprises a degassing unit 20. The degassing unit 20 serves to reliably remove battery gas. In certain exceptional cases (especially in the event of thermal runaway), for example due to overcharging or thermal overload, gas can be released from the interior of the battery cell 11. For a degassing event in which a single battery cell 11 releases gas from its interior via an overpressure mechanism, for example due to overcharging or thermal overload, a degassing unit 20 is provided in a battery housing. The released gas can expand into this unit, thereby reducing its temperature and pressure. The degassing unit 20 has a degassing opening 21 for the safe removal of battery gas from the battery cell 11 from the battery housing 12. The battery gas from the battery cell 11 is guided through the inlet opening 28 into the exhaust channel 24 of the degassing unit 20.The exhaust duct 24 is preferably designed as a cylindrical pipe.

[0043] A particle separator 22 is arranged in the exhaust duct 24. The particle separator 22 has a spiral guide element 25, which extends along a longitudinal axis x of the exhaust duct 24. Furthermore, the spiral guide element 25 has a plurality of turns 25.1, 25.2, 25.3. Due to the spiral geometry of the guide element 25, the emulsion (mixture and combustion gases) is set into rotation; the liquid components, in particular the cooling medium 14, are accelerated radially outwards by the resulting centrifugal force due to their higher density compared to the combustion gas, where they strike the inner wall 26 of the exhaust duct 24 or the pipe and are decelerated. The liquid components then flow downwards by gravity or out of the degassing unit 20, i.e. the exhaust gas channel 24, through the openings 22.1 in the wall 27.The rotating gas flow in the degassing unit 20, here the exhaust gas channel 24, supports this effect. The spiral guide element 25 is located in the . Fig. 1 is designed as a separate component and extends along a longitudinal axis x of the exhaust duct.

[0044] The proposed particle separator 22 with the spiral guide element 25 offers an efficient method for separating particles, especially liquid components and battery gas of the high-voltage battery 10.

[0045] The high-voltage battery 10 also includes a particle collector 23, which serves as a collection volume, particularly for the liquid components (e.g., from the cooling medium) of the mixture. Consequently, the liquid components separated by the particle separator 22 are directed through the openings 22.1 into the particle collector 23 and thus out of the degassing unit 20 or the exhaust duct 24, so that the components can be stored in the particle collector 23 and do not return to the degassing unit 20 or the exhaust duct 24. The separated liquid components therefore cannot be remixed with the battery gas and form an explosive mixture. This further increases safety.

[0046] In the Fig. Figure 2a shows a degassing unit 20 according to the invention, comprising a particle separator 22 with an exhaust gas channel 24 in which a guide element 25 is arranged. The exhaust gas channel 24 is designed as a cylindrical tube, and the guide element 25 is spirally shaped and has a plurality of turns 25.1, 25.2, 25.3. The spirally shaped guide element 25 is arranged in the exhaust gas channel 24 and extends along the inner wall 26 of the cylindrical exhaust gas channel 24. The particle separator 22 according to the invention thus has a helical or spirally shaped guide element 25 that imparts an additional rotational movement to the particles and the gas. This rotational movement generates a centrifugal force that pushes the heavier particles outwards, while the lighter gas remains in the center. The centrifugal force enables a clear separation of particles and gas. The liquid components flow downwards by gravity or through the openings 22.1 in the wall from the degassing unit 20, i.e., the exhaust duct 24. The rotating gas flow in the degassing unit 20, here the exhaust duct 24, supports this effect. As in . Fig. 2a shown and preferably at least one of the openings 22.1 is arranged between each pair of turns of the guide element 25.

[0047] In the Fig. 2b is a section of the in Fig. Figure 2a shows the exhaust channel 24. Here, the design and arrangement of the spiral guide element 25 according to the invention are particularly evident. The shown winding section of the guide element 25 extends along the inner wall 26 of the exhaust channel 24. The resulting spiral or helical geometry positively influences the flow of the mixture of battery gas and cooling medium. The geometry of the guide element 25 according to the invention imparts an additional rotational movement to the particles, in particular the liquid components and the gas. This rotational movement generates a centrifugal force that pushes the heavier particles outwards, while the lighter gas remains in the center. The centrifugal force enables a clear separation of the particles, i.e., the liquid components, and the gas. The liquid components and / or solid components (e.g., graphite dust) then flow towards the opening 22.1.Through the opening 22.1, which is formed in the wall 27 of the exhaust duct 24, the liquid and / or solid components then enter the particle collector 23, which is located on an outside of the exhaust duct 24.

[0048] Thus, the particle separator 22 according to the invention enables effective and energy-efficient particle separation of the gas mixture in the exhaust duct 24, which may consist of battery gas and heat transfer oil, for example in the event of a thermal runaway of a high-voltage battery, so that the liquid components of the gas mixture, i.e., the heat transfer oil, are separated from the battery gas. The liquid components are directed into the particle collector 23 and are separated there from the remaining gas (mixture). The liquid components, in particular the heat transfer oil, can then no longer be mixed with the remaining gas, so that the gas mixture is less hazardous.

[0049] In the Fig. Figure 3 shows an electric or hybrid vehicle 100 according to the invention with a high-voltage battery 10 according to the invention. The high-voltage battery 10 serves in particular as a traction battery for an electric drive of the electric or hybrid vehicle 100.

Claims

[1] High-voltage battery (10) for use in an electric or hybrid vehicle (100), comprising at least one battery cell (11) for storing electrical energy, a battery housing (12) for receiving the at least one battery cell (11), a cooling unit (13) with a cooling medium (14) for dissipating heat from the battery cell (11), and a degassing unit (20) with at least one degassing opening (21) for safely discharging battery gas from the battery cell (11) from the battery housing (12), further comprising a particle separator (22) for separating liquid components of a mixture of the battery gas and the cooling medium (14) in the event of outgassing from the battery cell (11), characterized by, that the degassing unit (20) has at least one exhaust gas channel (24) through which the battery gas expands, wherein the particle separator (22) is arranged on the exhaust gas channel (24), wherein the particle separator (22) has a plurality of openings (22.1) through which at least the liquid components of the mixture can be discharged from the degassing unit (20), wherein the particle separator (22) has a spiral guide element (25) and the spiral guide element (25) extends along a longitudinal axis (x) of the exhaust gas channel (24). [2] High-voltage battery (10) according to claim 1, characterized by , that a particle collector (23) is provided, wherein at least some of the liquid components of the mixture from the degassing unit (20) can be received in the particle collector (23). [3] High-voltage battery (10) according to claim 1 or 2, characterized by, that the openings (22.1) of the particle separator (22) are arranged in the wall (27) of the exhaust duct (24), wherein the openings (22.1) form connecting channels between the exhaust duct (24) and the particle collector (23). [4] High-voltage battery (10) according to any one of the preceding claims, characterized by , that the exhaust duct (24) is designed as a cylindrical pipe. [5] High-voltage battery (10) according to any one of the preceding claims, characterized by , that the openings (22.1) are arranged along the longitudinal axis of the exhaust duct (25). [6] High-voltage battery (10) according to any one of the preceding claims, characterized by , that the spiral guide element (25) has a plurality of turns (26.1, 26.2, 26.3), wherein at least one of the openings (22.1) is arranged between two successive turns (26.1, 26.2, 26.3). [7] High-voltage battery (10) according to any one of the preceding claims, characterized by, that the cooling medium (14) comprises a heat transfer oil. [8] Electric or hybrid vehicle (100) comprising a high-voltage battery (10) according to any one of claims 1 to 7.

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