DE102020207556B3 - Battery module housing - Google Patents

Abstract

The invention relates to a device (1) for detecting liquid (25) in a housing (2), comprising an RF source (6), at least one waveguide (9), at least one RF detector (14) and an evaluation unit ( 7), the RF source (6) being connected to one end (10) of the waveguide (9) and the RF detector (14) being connected to the other end (13) of the waveguide (9), the at least one waveguide (9) is arranged at least partially on the bottom (8) of the housing (2), the evaluation unit (7) being designed in such a way that a change in a signal at the RF detector (14) indicates liquid in the housing (2) (25) to close.

Description

The invention relates to a battery module housing with a device for detecting liquid in the battery module housing.

Incoming or outgoing liquid can pose a problem in particular in the case of housings in which electrical components are arranged, since short circuits or other functional impairments can then occur due to the liquid. One example is a battery module of an electric or plug-in hybrid vehicle, in which a plurality of battery modules form a traction battery, a plurality of battery cells being arranged in a battery module. In addition to water, leaking battery fluid can also be a problem.

From the WO 2016/060938 A2 a device for detecting moisture in a housing is known. The device has a passive RFID sensor with antenna structures that are laid on the floor. The impedance of the antenna structure varies depending on the presence of moisture and the type of moisture. An impedance matching circuit is provided in order to detect the change in impedance due to the liquid.

From the US 2019/0257935 A1 a radar transmitter for emulsion measurement is known. A pulse is sent to a transceiver via a probe. The probe includes an RF waveguide and is mounted on the bottom of the housing. A microprocessor evaluates the measured parameters and can deduce the liquid level.

From the DE 101 33 692 A1 a method for measuring the level of a liquid in a container is known. The liquid level is measured by feeding an RF signal into a waveguide.

From the U.S. 5,824,883 A a device for detecting liquid in a battery module housing is known.

The invention is based on the technical problem of creating an alternative and more robust device for detecting liquid in a battery module housing.

The solution to the technical problem results from a battery module housing with the features of claim 1. Further advantageous embodiments of the invention emerge from the subclaims.

For this purpose, the device for detecting liquid in the battery module housing has at least one RF source, at least one waveguide, at least one RF detector and an evaluation unit, the RF source with one end of the waveguide and the RF detector with the The other end of the waveguide is connected, the at least one waveguide being arranged at least partially on the bottom of the battery module housing, the evaluation unit being designed to determine liquid in the battery module housing from a change in a signal at the RF detector . Because of the fixed connection, the device is less prone to failure. This makes use of the fact that the wave resistance of the waveguide changes when liquid occurs, so that the signal at the RF detector changes accordingly. Typically the signal (e.g. a voltage signal) at the RF detector will decrease. In this case, for example, a threshold value can be defined so that if a signal at the HF detector is below the threshold value, a conclusion can be drawn about the liquid in the battery module housing.

In one embodiment, the RF source and / or the evaluation unit is integrated in a battery management control device. In this way, the control and evaluation of several battery modules can be carried out centrally in one control unit. A clock signal from a microprocessor, for example, which is typically already in the three-digit megahertz range, serves as the RF source. It can also be provided that harmonics are specifically generated by the clock signal, which are then coupled into the waveguide.

In a further embodiment, structural elements arranged in the battery module housing have openings through which liquid that has entered can be distributed over the bottom of the battery module housing. These structural elements can be, for example, connecting or crash struts or partitions. This prevents liquid from collecting at individual points in the battery module housing, but the area where the waveguide is laid remains dry.

In a further embodiment, the housing base has a recess, the waveguide being arranged at least partially in the recess. This simplifies the detection of liquid, since a significant change in the wave resistance occurs more quickly.

In a further embodiment, the waveguide is applied to a substrate which is fastened at least to the bottom of the battery module housing. The substrate is glued, for example or screwed. The substrate is, for example, rigid and consists of FR-4 or AI203.

In a further embodiment, the substrate is designed as a flexible substrate (e.g. FR-4, 0.127 mm-0.254 mm thick) and additionally adjoins at least one side wall of the battery module housing. This makes the HF connectors more accessible.

In a further embodiment, the at least one waveguide is designed as a microstrip line or as a coplanar line.

In a further embodiment, the RF detector is designed as a Schottky diode. The HF detector can be arranged both inside the housing and outside the battery module housing.

In a further embodiment, the RF detector has an adaptation circuit to the characteristic impedance of the at least one waveguide. The HF detector can thus be optimally adapted to the dry wave impedance so that the signal at the HF detector has a maximum in the dry state. The coupling of the HF power is preferably also adapted to the characteristic impedance.

• 1 eine schematische Darstellung einer Vorrichtung zur Erfassung von Flüssigkeit in einem Gehäuse,
• 2 eine schematische Darstellung einer Seitenansicht einer Mikrostreifenleitung,
• 3 eine Draufsicht auf ein Substrat mit einer Mikrostreifenleitung,
• 4 eine schematische Darstellung eines Strukturelements und
• 5 eine schematische Darstellung eines Gehäuses mit einer Vertiefung.

The invention is explained in more detail below on the basis of preferred exemplary embodiments. The figures show:

• 1 a schematic representation of a device for detecting liquid in a housing,
• 2 a schematic representation of a side view of a microstrip line,
• 3 a plan view of a substrate with a microstrip line,
• 4th a schematic representation of a structural element and
• 5 a schematic representation of a housing with a recess.

In the 1 is schematically a device 1 for the detection of liquids in a housing 2 shown, with the housing 2 as a battery module housing 3 is trained. The device 1 further has a battery management control unit 4th on that a microprocessor 5 having both an RF source 6th as well as an evaluation unit 7th the device 1 forms. On the ground 8th of the housing 2 is a waveguide 9 upset. The waveguide 9 is at one end 10 via an RF connector 11 as well as an RF line 12th with the RF source 6th tied together. On the other end 13th is the waveguide 9 with an RF detector 14th connected via another line 15th with the evaluation unit 7th connected is. The evaluation unit 7th detects changes in the signal at the RF detector 14th as a function of the liquid, which affects the wave resistance of the waveguide 9 changes. Assuming that there is complete adaptation in the dry state, the change in the characteristic impedance leads to reflections, so that the signal at the RF detector 14th decreases. A threshold value can be defined, below which it can be concluded that the liquid is present. A user can then be informed about this, for example, in order to carry out appropriate measures if necessary.

In the 2 is the waveguide 9 in the form of a microstrip line 16 shown being on a substrate 17th is applied, with a ground conductor 18th on the underside of the substrate 17th is upset.

In the 3 Fig. 3 is a plan view of the substrate 17th shown. The RF detector 14th is called a Schottky diode 19th (for example in SMD design) with a matching circuit 20th for the wave resistance of the waveguide 9 formed, the voltage across the Schottky diode 19th the output signal U _A is that of the evaluation unit 7th (please refer 1 ) is evaluated. On the HF connector 11 are still vias 21 to the ground conductor 18th on the underside of the substrate 17th shown.

In the 4th Fig. 3 is a schematic front view of a sectioned housing 2 shown, being a structural element 22nd such as a wall or a crash strut extending over the full width. The structural element 22nd at least one opening 23 on, through which the liquid moves inside the housing 2 across the floor 8th can distribute.

The soil can do this 8th a depression 24 have in which the waveguide 9 lies (see 5 ). Liquid preferentially collects in the depression 25th so that the detection takes place very quickly.

List of reference symbols

1

contraption

2

casing

3

Battery module housing

4th

Battery management control unit

5

microprocessor

6th

RF source

7th

Evaluation unit

8th

floor

9

Waveguide

10

end

11

RF connector

12th

RF line

13th

end

14th

RF detector

15th

management

16

Microstrip line

17th

Substrate

18th

Ground conductor

19th

Schottky diode

20th

Matching circuit

21

Via

22nd

Structural element

23

opening

24

deepening

25th

liquid

Claims (9)

Battery module housing (3) with a device (1) for detecting liquid (25) in the battery module housing (3), the device (1) having an RF source (6), at least one waveguide (9), at least an RF detector (14) and an evaluation unit (7), the RF source (6) with one end (10) of the waveguide (9) and the RF detector (14) with the other end (13) of the Waveguide (9) is connected, the at least one waveguide (9) being arranged at least partially on the bottom (8) of the battery module housing (3), the evaluation unit (7) being designed from a change in a signal at the HF -Detector (14) to close in the battery module housing (3) located liquid (25). Battery module housing Claim 1 , characterized in that the HF source (6) and / or the evaluation unit (7) is integrated in a battery management control device (4). Battery module housing according to one of the preceding claims, characterized in that structural elements (22) arranged in the battery module housing (3) have openings (23) through which liquid (25) penetrates above the bottom (8) of the battery module housing (3) can distribute. Battery module housing according to one of the preceding claims, characterized in that the bottom (8) of the battery module housing (3) has a recess (24), the waveguide (9) being at least partially arranged in the recess (24). Battery module housing according to one of the preceding claims, characterized in that at least the waveguide (9) is applied to a substrate (17) which is fastened at least to the bottom (8) of the battery module housing (3). Battery module housing Claim 5 , characterized in that the substrate (17) is designed as a flexible substrate and additionally rests against at least one side wall of the battery module housing (3). Battery module housing according to one of the preceding claims, characterized in that the at least one waveguide (9) is designed as a microstrip line (16) or as coplanar lines. Battery module housing according to one of the preceding claims, characterized in that the HF detector (14) is designed as a Schottky diode (19). Battery module housing according to one of the preceding claims, characterized in that the HF detector (14) has an adaptation circuit (20) to the characteristic impedance of the at least one waveguide (9).

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