High-voltage storage device for a motor vehicle

Abstract

The invention relates to a high-voltage storage device (10) for a motor vehicle, the device comprising a housing (11) which delimits an interior (15) of the high-voltage storage device (10), and at least one battery cell (13) is arranged in the interior (15). The high-voltage storage device (10) has a flow channel (12) which has an inlet (21) and an outlet (22) and is configured to fluidically connect the interior (15) to the surroundings (U) of the high-voltage storage device (10) and to discharge a degassing flow (E) of at least one battery cell (13) from the interior (15).

Description

[0001] High-voltage storage for a motor vehicle

[0002] The invention relates to a high-voltage storage device for a motor vehicle, comprising a housing which defines an interior space of the high-voltage storage device and in which at least one battery cell is arranged, wherein the high-voltage storage device has a flow channel with an inlet and an outlet which is configured to connect the interior space with an environment of the high-voltage storage device in a fluid-permeable manner and to discharge a degassing flow from at least one battery cell out of the interior space.

[0003] High-voltage storage devices, also known as traction batteries or accumulators, are used to provide electrical energy for powering electric motors in motor vehicles. These high-voltage storage devices typically consist of an arrangement of battery cells connected in parallel and series via a contacting device, all housed within a casing. Because these battery cells can release a considerable amount of energy in the event of a failure, the battery cells of a high-voltage storage device, particularly lithium-ion batteries, have vents that serve as a safety mechanism. These vents allow gases to escape that may form under predetermined conditions, such as overcharging, overheating, or an internal short circuit. These high-temperature and high-pressure gases, as well as liquid and solid impurities, must be vented quickly and effectively.

[0004] When mixed with atmospheric oxygen outside the high-voltage storage system, this gas can ignite because its temperature may exceed the ignition temperature. Therefore, the high-voltage storage system can have a dedicated flow channel that acts as a cooling section. As the gas flows through this cooling section, energy is transferred from the gas flow to the channel, thus cooling it. However, such cooling sections are limited by space, cost, and weight. Against this background, an object of the invention is to improve a high-voltage storage system for a motor vehicle. In particular, a cooling section for the degassing flow of at least one battery cell is to be improved to enable sufficient cooling of the degassing flow, especially to improve the safety of the high-voltage storage system.

[0005] This problem is solved by a high-voltage storage device for a motor vehicle with the features of claim 1 and a flow guidance device with the features of claim 10. The dependent claims relate to advantageous further developments of the invention.

[0006] According to a first aspect, a high-voltage storage device for a motor vehicle is specified, comprising a housing which defines an interior space of the high-voltage storage device and in which at least one battery cell is arranged, wherein the high-voltage storage device has a flow channel with an inlet and an outlet which is configured to connect the interior space with an environment of the high-voltage storage device in a fluid-flowable manner and to discharge a degassing flow from at least one battery cell out of the interior space, wherein the flow channel has at least one inlet opening which is configured to connect the interior space with the flow channel in a fluid-flowable manner.

[0007] This allows air from the high-voltage storage system to be supplied to the flow channel via at least one inlet opening, where it can mix with the degassing flow and thereby, in particular, further cool it. Such an additional cooling effect allows for a shorter flow channel or cooling section.

[0008] A high-voltage storage system is, in particular, an energy storage device or traction battery for a motor vehicle, comprising several cylindrical battery cells. These battery cells are typically cylindrical and can be arranged, for example, in a hexagonal packing configuration. A battery cell can, for instance, have a circular cross-section and a longitudinal axis perpendicular to it. The battery cell can be bounded longitudinally by two end faces, which are connected by a cell shell or surface. Of course, battery cells with other cross-sections, such as rectangular, hexagonal, or prismatic cross-sections, can also be used.In an installation situation in a motor vehicle, the high-voltage storage system and / or the battery cells can be arranged such that the longitudinal axes of the battery cells are arranged parallel to a vehicle vertical.

[0009] Each cylindrical battery cell is provided with a degassing port designed to release gases that may form during overcharging, overheating, and / or an internal short circuit. The degassing port is equipped, in particular by means of at least one safety valve and / or predetermined breaking point integrated into the cylindrical battery cell, to release the degassing flow in a controlled manner once a predetermined internal pressure is reached, without the battery cell itself rupturing or exploding. Such degassing prevents the increasing pressure from damaging the internal structures of the battery cell, thus preserving the integrity of the battery cell and reducing the likelihood of a short circuit and / or other mechanical damage.

[0010] The degassing opening can have a circular or otherwise shaped cross-section and / or is arranged on a battery cell, particularly on at least one of its end faces, to prevent other battery cells from being directly exposed to the degassing flow during a degassing process and to direct the flow towards the housing. A structural element can be provided between the battery cells and the housing to define a distance between the battery cells or their degassing openings, thus defining a degassing chamber within the high-voltage storage system. This chamber allows the degassing flow to flow to the inlet of the flow channel, enter it, and exit the high-voltage storage system through the outlet to be released into the surrounding environment.

[0011] The flow channel is specifically designed to direct the degassing flow from the interior to the outside and release it into the environment. The flow channel has an inlet with a predetermined cross-sectional area through which the degassing flow can enter the channel, and an outlet through which the degassing flow can exit the channel. The flow channel can be configured to influence at least one flow characteristic, such as velocity, pressure, and / or direction of the degassing flow, in order to achieve a desired cooling effect.

[0012] The invention is based, among other things, on the idea of ​​utilizing the flow velocity of the degassing stream within the cooling section or flow channel to draw in air from a region of the high-voltage storage device where the air is cooler relative to the degassing stream. To this end, it is proposed to provide at least one inlet opening in the flow channel to utilize the negative pressure generated by the degassing stream and its flow velocity to draw in air from the interior of the high-voltage storage device and use it for secondary air mixing to cool the degassing stream. The flow channel can also include at least one deflector to separate particles present in the degassing stream, thereby preventing or even eliminating them as an additional ignition source.For this purpose, the flow channel between the inlet and the outlet can have a predetermined length to allow for a predetermined cooling of the degassing flow.

[0013] By providing at least one inlet opening, a pressure drop can be generated along the cooling section, which can contribute to further cooling of the degassing flow. This allows the temperature of the degassing flow to be reduced to below its auto-ignition temperature. Furthermore, the additional cooling effect achievable through the at least one inlet opening enables a shorter cooling section or flow channel. This reduces the required installation space and thus saves on the cost and / or weight of the high-voltage storage system.

[0014] In one embodiment, the at least one inlet opening has a smaller cross-section than the inlet of the flow channel. The inlet of the flow channel can have a predetermined size, designed to accommodate a flow or mass flow typically expected during a thermal event, and to discharge this flow, particularly after appropriate cooling, to the environment via the outlet. The at least one inlet opening has a flowable cross-section that is smaller than the flowable cross-section of the inlet opening, so that a negative pressure can be generated in the flow channel between the inlet and outlet, allowing air to be drawn in from the high-voltage storage device through the inlet opening. The inlet opening can be configured to have approximately 1 / 8, 1 / 10, or 1 / 12 the cross-section of the inlet of the flow channel.

[0015] In one embodiment, the flow channel has a predetermined number of inlet openings along its flow direction. The flow direction runs, in particular, from the inlet to the outlet, with the inlet facing the interior of the high-voltage storage system and the outlet facing the environment of the high-voltage storage system. The flow direction can, for example, run along a housing wall and / or parallel to it. The number of inlet openings can be arranged along an axis and / or irregularly distributed along the flow channel to achieve a predetermined intake of secondary air or air from the interior of the high-voltage storage system and thus a desired cooling effect. The number can be, for example, 2, 3, 4, 5, 6, or more. In one embodiment, the size of the inlet openings varies along the flow direction. Here, a size or...The cross-sectional area of ​​the inlet openings can be increased or decreased along the flow direction to allow a predetermined inflow of secondary air. It may be possible for the size of the inlet openings to change in a predetermined ratio along the flow direction and / or for them to be arranged at different heights, for example, relative to a longitudinal axis of the battery cells, in order to draw in cooler air from the high-voltage storage system by increasing the distance to the degassing openings of the battery cells, thus enabling mixing with the degassing flow and improving the cooling effect.

[0016] In one embodiment, the at least one inlet opening is designed as a slot opening. A slot opening is, in particular, an elongated and / or narrow opening that can be configured to allow for a uniform mixing of secondary air. In other embodiments, the at least one outlet opening may have a circular, oval, hexagonal, or otherwise shaped cross-section to enable the desired mixing of air. Circular openings, for example, can be manufactured in a cost-effective manner.

[0017] In one embodiment, the slot opening is arranged transversely to the flow direction. Here, a longitudinal axis of the elongated slot opening is oriented perpendicular to the flow direction in order to allow secondary air to flow in above a predetermined height of the degassing flow or flow channel, thus achieving an improved cooling effect.

[0018] In one embodiment, the flow channel is arranged along the housing of the high-voltage storage device. The inlet of the flow channel, or its inlet cross-section, can be arranged perpendicular to the flow direction or to the housing, and / or can be oriented towards a plane of the degassing openings to allow for deflection of the degassing flow and thus particle separation. In other embodiments, the inlet, or its inlet cross-section, can form an angle with the housing. The outlet is then arranged within the housing or a plane of the housing, allowing the degassing flow to be released into the environment.

[0019] In one embodiment, the flow channel is formed by means of a flow guide device arranged on the housing of the high-voltage storage device. The flow channel can, for example, be formed by means of at least one shaped metal sheet and / or a plastic part, particularly one designed to be temperature-resistant, which can be arranged on the housing, a housing side wall, or relative to the outlet formed in the housing by means of suitable fastening means in order to allow the degassing flow to escape.

[0020] In one embodiment, the flow guide forms the at least one inlet opening. It can be provided that the flow guide has at least one opening or recess facing the interior, which forms the at least one inlet opening and can be designed in the manner described herein. In particular, it is provided that the at least one inlet opening has a predetermined distance from the inlet, which, in particular together with the housing, can be formed by the flow guide, in order to provide a predetermined temperature difference between the degassing flow and the additional high-voltage storage air.

[0021] According to a further aspect, a flow guidance device for a high-voltage storage device is specified, wherein the flow guidance direction is configured for use in a high-voltage storage device described herein. In particular, the flow guidance device is configured to form the flow channel, especially together with the housing, in order to mix air from the high-voltage storage device with the degassing flow to cool it and thus improve its cooling.

[0022] Further advantages and application possibilities of the invention will become apparent from the following description in conjunction with the figures.

[0023] Fig. 1 shows a schematic representation of a high-voltage storage device for a motor vehicle according to an embodiment of the present invention.

[0024] Fig. 2 shows a further schematic representation of the high-voltage storage system for a motor vehicle according to the embodiment shown in Fig. 1.

[0025] Fig. 1 shows an embodiment of a high-voltage storage device 10 according to the invention with a housing 11 and a flow channel 12 in a schematic sectional view.

[0026] The high-voltage storage device 10 comprises a plurality of battery cells 13, which are arranged in a cell pack and contained within an interior space 15 bounded by the housing 11. Each of the battery cells 13 has a degassing opening 14 facing the housing 11, or in this case, the base of the housing. The degassing opening 14 is located on an end face of the battery cell 13 and is designed, particularly in the event of a failure or fault (represented here by reference numeral T), to release gases generated or already generated in the battery cell 13 as a degassing flow 15.

[0027] In particular, an increase in internal pressure within the interior 15 can cause the degassing flow E to flow to the flow channel 12. This flow channel has an inlet 21 facing the interior 15 and an outlet 22 arranged in a housing wall and is designed to connect the interior 15 to the environment U of the high-voltage storage unit 10 via a fluid flow, in order to cool the degassing flow E and discharge it to the environment U.

[0028] The flow channel 12 is formed by means of a flow guide 20 arranged on the housing 11 of the high-voltage storage unit 10 and has a number of inlet openings 23. Each of the inlet openings 23 is designed to allow fluid flow through the interior 15 to the flow channel 12, in order to supply and / or mix air L from the interior 15 of the high-voltage storage unit 10, or secondary air, into the degassing flow E in the flow channel 12 and thus, in particular, to cool it further. This allows the flow channel 12, or a cooling section for the degassing flow E, to be shortened, thereby reducing the required installation space.

[0029] In Fig. 2, the high-voltage storage unit 10 from Fig. 1 is shown in a schematic side section view, whereby a representation of the battery cells 13 has been omitted for the sake of improved clarity.

[0030] It can be seen that the inlet openings 23 have a smaller cross-section than the inlet 21 of the flow channel 12 or the inlet 21 formed by the flow guide 20 and the housing 11. The size or flowable cross-section of the inlet openings 23 can vary along a flow direction RE of the flow channel 12 to allow a predetermined inflow of air L from the interior 15 of the high-voltage storage unit 10. In the present embodiment, the inlet openings 23 are designed as slot openings, with the slot opening or its longitudinal axis arranged transversely to the flow direction E in order to improve the mixing of air L with the degassing flow E, to improve the cooling effect, and in particular to prevent spontaneous ignition of the degassing flow E at the outlet 22 or upon entry into the environment U. REFERENCE SYMBOL LIST

[0031] 10 high-voltage storage units

[0032] 11 cases

[0033] 12 Flow channel 13 Battery cell

[0034] 14 Degassing opening

[0035] 15 Interior

[0036] 20 Flow guidance device

[0037] 21 Entry 22 Exit

[0038] 23 Inlet opening

[0039] E Degassing flow

[0040] L air

[0041] T Battery fault RE Flow direction

[0042] U surroundings

Claims

REQUIREMENTS 1. High-voltage storage device (10) for a motor vehicle, comprising a housing (11) which defines an interior space (15) of the high-voltage storage device (10) and in which at least one battery cell (13) is arranged, wherein the high-voltage storage device (10) has a flow channel (12) with an inlet (21) and an outlet (22) which is configured to allow fluid flow through the interior space (15) to an environment (U) of the high-voltage storage device (10) and to discharge a degassing flow (E) from at least one battery cell (13) out of the interior space (15), wherein the flow channel (12) has at least one inlet opening (23) which is configured to allow fluid flow through the interior space (15) to the flow channel (12).

2. High-voltage storage device (10) according to the preceding claim, wherein the at least one inlet opening (23) has a smaller cross-section than the inlet (21) of the flow channel (12).

3. High-voltage storage device (10) according to one of the preceding claims, wherein the flow channel (12) has a predetermined number of inlet openings (23) along its flow direction (RE).

4. High-voltage storage device (10) according to the preceding claim, wherein the size of the inlet openings (23) varies along the flow direction (E).

5. High-voltage storage device (10) according to one of the preceding claims, wherein at least one inlet opening (23) is designed as a slot opening.

6. High-voltage storage device (10) according to the preceding claim, wherein the at least one slot opening is arranged transversely to the flow direction (RE).

7. High-voltage storage device (10) according to one of the preceding claims, wherein the flow channel (12) is arranged along the housing (11) of the high-voltage storage device (10).

8. High-voltage storage device (10) according to one of the preceding claims, wherein the flow channel (12) is formed by means of a flow guidance device (20) which is arranged on the housing (11) of the high-voltage storage device (10).

9. High-voltage storage device (10) according to the preceding claim, wherein the flow guidance device (20) forms at least one inlet opening (23).

10. Flow guidance device (20) for a high-voltage storage device (10), wherein the flow guidance device (20) is configured to be used in a high-voltage storage device (10) according to one of the preceding claims.

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