Traction Battery for a Motor Vehicle, Motor Vehicle, and Method for Controlling Degassing Elements of a Traction Battery

Abstract

A traction battery for a motor vehicle includes a plurality of battery cells which are electrically connected to one another, a battery housing which houses the battery cells, several degassing elements for conducting gas away out of the battery housing in the case of a cell outgassing, a sensing system for localizing the cell outgassing, and a control unit which, in the case of a cell outgassing, actuates the degassing elements such that the degassing element situated nearest the cell outgassing remains closed and one or more of the degassing elements that are farther away from the cell outgassing is/are opened.

Claims

1. A traction battery for a motor vehicle, the traction battery comprising: a plurality of battery cells which are electrically connected to one another; a battery housing which houses the battery cells; a plurality of degassing elements for conducting gas out of the battery housing in a case of a cell outgassing; a sensing system for localizing the cell outgassing; and a control unit which, in the case of the cell outgassing, actuates the degassing elements such that a first degassing element situated nearest the cell outgassing remains closed and one or more other degassing elements that are farther away from the cell outgassing are opened.

2. The traction battery according to claim 1, wherein at least a second degassing element that, of all the degassing elements in the battery housing in the case of the cell outgassing, is farthest away from the cell outgassing, is opened by the control unit.

3. The traction battery according to claim 1, wherein the sensing system comprises a plurality of temperature sensors.

4. The traction battery according to claim 1, wherein the sensing system comprises a voltage-monitoring device with which a drop in voltage at one or more of the battery cells is detectable, in order to detect the cell outgassing.

5. The traction battery according to claim 1, wherein the sensing system comprises an optical capture device.

6. A motor vehicle comprising the traction battery according to claim 1.

7. A method for controlling degassing elements for conducting gas out of a battery housing of a traction battery for a motor vehicle, the method comprising: identifying a cell outgassing; localizing the cell outgassing by a sensing system; actuating the degassing elements such that in a case of the cell outgassing, a first degassing element situated nearest the cell outgassing remains closed and one or more other degassing elements that are farther away from the cell outgassing are opened.

8. The method according to claim 7, wherein at least a second degassing element that, of all the degassing elements in the battery housing in the case of the cell outgassing, is farthest away from the cell outgassing, is opened by the control unit.

9. The method according to claim 7, wherein localizing the cell outgassing comprises using temperature sensors.

10. The method according to claim 7, wherein localizing the cell outgassing comprises using a voltage-monitoring device with which a drop in voltage at one or more of the battery cells is registered, in order to detect the cell outgassing.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0017] FIG. 1 shows schematically a traction battery 1 according to an embodiment of the invention.

DETAILED DESCRIPTION OF THE DRAWING

[0018] The traction battery 1 has been installed in a motor vehicle which is not represented. The motor vehicle is an electrified motor vehicle which, at least at times, is propelled purely electrically. In particular, it may be a passenger car.

[0019] The traction battery 1 includes a plurality of battery cells 2 which are electrically connected to one another. For instance, the battery cells 2 may have been electrically connected in series and/or in parallel. The battery cells 2 are electrochemically-based cells for storing and providing electrical energy at least for the drive of the motor vehicle—that is to say, for supplying one or more drive motors. The battery cells 2 may be cylindrical cells or (as shown by way of example) rectangular-cuboid cells. In case of a fault, particularly in the event of a thermal runaway of the battery cell 2, a battery cell 2 might outgas—that is to say, hot gases might emerge from the battery cell, that is to say, a cell outgassing 3 is present.

[0020] The battery cells 2 are housed in a battery housing 4 which separates the battery cells 2 from the environment of the battery housing 4 in a fluid-tight manner or hermetically.

[0021] Degassing elements 5 (at least two, for instance also three, four or more) are arranged in or on one or more walls of the battery housing 4. In normal operation—that is to say, when a cell outgassing 3 of a battery cell 2 is not present—the degassing elements 5 are closed in fluid-tight manner. In the case of a cell outgassing 3 of at least one battery cell 2, at least one of the degassing elements 5 is opened, so that the hot gases emerging from the outgassing battery cell 2 can escape from the battery housing 4 to the environment via the opened degassing element(s) 5—that is to say, outside the battery housing 4—in particular to a region surrounding the motor vehicle. The degassing elements 5 are valves, flaps or such like which are capable of being actuated.

[0022] In addition, the traction battery 1 includes a control unit 6 which has been adapted to actuate the degassing elements 5. The control unit 6 may have been arranged in, on or outside the battery housing 4.

[0023] Furthermore, a sensing system 7 is provided which communicates detection signals to the control unit 6. The control unit 6 may have been connected to the degassing elements 5 and to the sensing system 7 via wires, cables, or in wireless manner. The sensing system 7 may include several temperature sensors, pressure sensors and/or temperature/pressure sensors spaced from one another. In FIG. 1, temperature sensors are indicated as an example of the sensing system 7. Additionally or alternatively, the sensing system 7 may include a voltage-monitoring device which monitors a voltage of the individual battery cells 2 and, in the event of a drop in voltage occurring, determines that a cell outgassing 3 of a particular battery cell 2 is present, and can infer the position of the cell outgassing 3 with the aid of stored positions of the individual battery cells 2. In addition, the sensing system 7 may include an optical capture device, for example an optical camera or a thermal-imaging camera, by way of which a cell outgassing 3 is capable of being identified and localized.

[0024] In the case of a detected cell outgassing 3 and the localization of the cell outgassing 3, the control unit 6 controls the degassing elements 5 in such a manner that at least the degassing element 5 that has the shortest spacing from the cell outgassing 3 remains closed. The degassing elements 5 are to be configured structurally in such a way that they are not opened unintentionally even by a pressure surge possibly arising as a result of the cell outgassing 3. Of the remaining degassing elements 5, one or more is/are opened. At least a single degassing element 5 is opened, specifically that one which has the largest spacing from the cell outgassing 3.

[0025] As a result, the stream of gas within the battery housing 4 has to travel a certain distance before the stream of gas escapes to the environment, so the interior of the battery housing serves as cooling path for the hot stream of gas.

[0026] Whilst the invention has been illustrated and described in detail in the drawing and in the foregoing description, this illustration and description is to be understood as being exemplary and not restrictive, and it is not the intention to restrict the invention to the disclosed embodiment. The mere fact that certain features have been mentioned in various dependent claims is not intended to suggest that a combination of these features might not also be utilized advantageously.

[0027] The foregoing disclosure has been set forth merely to illustrate the invention and is not intended to be limiting. Since modifications of the disclosed embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construed to include everything within the scope of the appended claims and equivalents thereof.