Method and device for detecting a defect in an electrical energy storage device

Abstract

The invention relates to a method and a device (12) for detecting a defect in an electrical energy storage device (1), which has a housing (2) in which a plurality of electrochemical cells (4) are arranged, which are cooled directly in the housing (2) by means of an electrically non-conductive cooling fluid (8), wherein at least one conductive measuring probe (12.1) is arranged in the housing (2), which is coupled to a conductivity sensor (12.2) by means of which the electrical conductivity of the cooling fluid (8) is measured.

Description

[0001] The invention relates to a method and a device for detecting a defect in an electrical energy storage device, as well as an electrical energy storage device with such a device.

[0002] It is known from automotive engineering that, particularly for at least partially electric operation of a motor vehicle, and especially for fully electric operation, a corresponding electrical energy storage system is installed in the vehicle. This electrical energy storage system can, in particular, comprise a plurality of battery cells or battery modules. Due to the high power requirements of these battery cells, they generate heat, for example, during power input or output, so that they must be cooled accordingly for improved operation. In particular, a non-conductive cooling medium can be used to circulate around the battery cells or battery modules to enable heat dissipation.The waste heat from this cooling process is then dissipated, for example, via a water heat exchanger, which can be located directly at the battery or electrical energy storage device. Leaks in the heat exchanger can lead to water entering the electrical energy storage device, which, under unfavorable conditions, can result in the formation of explosive hydrogen and an explosion.

[0003] From DE 10 2019 008 073 A1, a detection device for detecting water in a cooling device of an electrical energy storage device is known, which has at least one condenser device through which the cooling fluid flows and detects the water within the cooling fluid depending on a change in capacitance within the condenser device.

[0004] The invention is based on the objective of providing an improved method and an improved device for detecting a defect in a cell module of an electrical energy storage device, as well as an electrical energy storage device with such an improved device.

[0005] The first problem is solved according to the invention by a method for detecting a defect in an electrical energy storage device, in particular in a cooling system of the energy storage device, with the features of claim 1. The second problem is solved according to the invention by a device for detecting a defect in an electrical energy storage device with the features of claim 4. The third problem is solved according to the invention by an electrical energy storage device with the features of claim 6.

[0006] Advantageous embodiments of the invention are the subject of the dependent claims.

[0007] The inventive method for detecting a defect in an electrical energy storage device, which has a housing in which a plurality of cells are arranged and which are cooled directly in the housing by means of an electrically non-conductive cooling fluid, provides that at least one conductive measuring probe is or will be arranged in the housing, which is or will be coupled to a conductivity sensor which measures the electrical conductivity of the cooling fluid.

[0008] The invention is based on the premise that water can enter the cooling fluid (also called cooling medium), in particular a cooling oil, through a leak in the cooling circuit and / or the housing. The water can then settle, for example, in the cell modules and the housing due to gravity. Alternatively, the water can circulate as an oil-water emulsion within the cooling circuit, particularly a cooling oil circuit. In this case, water is detected by measuring the conductivity of the emulsion, the oil, or the water.

[0009] In particular, the conductivity sensor is used to determine, based on the measured electrical conductivity of the cooling fluid, whether water has entered the housing.

[0010] By means of the invention, the danger of the formation of flammable / explosive hydrogen through electrolysis of the water can be detected based on the measured electrical conductivity and the derived determination of water in the cooling fluid, and suitable measures, such as switching off the electrical energy storage device, can be taken.

[0011] By measuring the conductivity of the cooling fluid via the conductive measuring probe directly in the housing exposed to the cooling fluid, water in the cooling circuit of the electrical energy storage device (also called battery) can be detected particularly easily and safely.

[0012] For example, at least one conductive trace arranged in the housing is used as a measuring probe and is directly exposed to the cooling fluid. The conductor(s) can also be arranged in and / or on any other component of the directly cooled electrical energy storage device. For example, the at least one conductor can be arranged on a coolant distributor, a coolant pump, or the like, in such an area or section of these components that is directly exposed to the cooling fluid in order to detect water in the cooling fluid.

[0013] Preferably, the conductor tracks are integrated at the lowest point of the electrical energy storage device, in particular on a lower cover or on a base of the housing of the energy storage device and / or the cell modules.

[0014] The device according to the invention for detecting the defect of the energy storage device provides in the battery housing at least one conductive measuring probe which is coupled to the conductivity sensor which is configured to measure the electrical conductivity of the cooling fluid.

[0015] The electrical energy storage device according to the invention comprises a plurality of cells arranged in a housing and the previously described device for detecting a defect in the cell module. The electrical energy storage device is, in particular, a high-voltage battery of a vehicle. The cells are, in particular, galvanic cells, which are, for example, designed as cylindrical cells.

[0016] Exemplary embodiments of the invention are explained in more detail below with reference to drawings.

[0017] This shows: Fig. 1. Schematic exploded view of an electrical energy storage device with a housing and a plurality of cells and a device for detecting a defect with a conductive measuring probe, and Fig. Figure 2 schematically shows another example of a conductive measuring probe.

[0018] Corresponding parts are marked with the same reference symbols in all figures.

[0019] Fig. Figure 1 schematically shows an exploded view of an electrical energy storage device 1 with a housing 2 and a plurality of cell modules or cells 4, in particular galvanic cells 4 (also called electrochemical cells 4).

[0020] A cooling circuit 6 is provided for cooling the cells 4. This circuit introduces a cooling fluid 8, in particular a cooling oil, into the housing 2 via an inlet 6.1 and discharges it via an outlet 6.2. This is purely exemplary and by no means exhaustive. It can be seen, in particular, that the cooling fluid 8 is also used for cooling in the spaces between the cells 4. Thus, the cooling fluid 8 is designed to directly cool a cell housing wall of the cells 4. The cells 4 are, for example, designed as cylindrical cells.

[0021] The housing 2 can be made up of multiple parts. In the example, the housing 2 comprises a container 2.1, which can be sealed fluid-tight by means of a lid 2.2, for example at the bottom 10.

[0022] The electrical energy storage device 1 further comprises a device 12 for detecting a defect in the electrical energy storage device 1. The device 12 comprises at least one conductive measuring probe 12.1. The at least one conductive measuring probe 12.1 is coupled to a conductivity sensor 12.2, which is configured to measure the electrical conductivity of the cooling fluid 8.

[0023] For this purpose, at least one conductive measuring probe 12.1 is / will be arranged in the housing 2, which is coupled to the conductivity sensor 12.2, which measures the electrical conductivity of the cooling fluid 8.

[0024] In particular, the conductivity sensor 12.2 is used to determine, based on the measured electrical conductivity of the cooling fluid 8, whether water has entered the housing 2.

[0025] By measuring the conductivity of the cooling fluid 8 via the conductive measuring probe 12.1 directly in the housing 2 supplied with cooling fluid 8, water in the cooling circuit 6 of the electrical energy storage device 1 (also called battery) can be detected particularly easily and safely.

[0026] For example, at least one conductor track 12.1.1 arranged in the housing 2 is used as a conductive measuring probe 12.1, which is directly exposed to the cooling fluid 8.

[0027] The conductor track(s) 12.1.1 can, for example, also be arranged in and / or on any other component of the directly cooled electrical energy storage device 1. For example, the at least one conductor track 12.1.1 can be arranged on a coolant distributor, a coolant pump, or the like in the cooling circuit 6, in particular in such a region or section of these components that are directly exposed to the cooling fluid 8 in order to detect water in the cooling fluid 8.

[0028] Preferably the conductor tracks 12.1.1 are integrated at the lowest point of the electrical energy storage device 1, in particular on the lower cover 2.2 or on a base 10 of the housing 2 of the energy storage device 1 and / or the cell modules.

[0029] In the example, the conductor tracks 12.1.1 are arranged parallel to each other on an inner side of the lower cover 2.2.

[0030] Fig. Figure 2 schematically shows another example of a conductive measuring probe 12.1. The conductive traces 12.1.1 are applied directly to the inside of the lower cover 2.2 using laser technology. The conductive traces 12.1.1 are arranged in a meandering structure. Reference symbol list 1 Energy storage 2 cases 2.1 Container 2.2 Lid 4 cells 6 Cooling circuit 6.1 Entrance 6.2 Exit 8 Cooling fluid 10 Floor 12 Device 12.1 Measuring probe 12.1.1 Conductor track 12.2 Conductivity sensor QUOTES INCLUDED IN THE DESCRIPTION

[0000] 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

[0000] DE 10 2019 008 073 A1

[0003]

Claims

[1] Method for detecting a defect in an electrical energy storage device (1) which has a housing (2) in which a plurality of electrochemical cells (4) are arranged which are cooled directly in the housing (2) by means of an electrically non-conductive cooling fluid (8), characterized by , that at least one conductive measuring probe (12.1) is arranged in the housing (2), which is or will be coupled to a conductivity sensor (12.2) by means of which the electrical conductivity of the cooling fluid (8) is measured. [2] Method according to claim 1, characterized by , that by means of the conductivity sensor (12.2) it is determined, based on the detected electrical conductivity of the cooling fluid (8), whether water has entered the housing (2). [3] Method according to claim 1 or 2, characterized by, that at least one conductor track (12.1.1) arranged in the housing (2) is used as a conductive measuring probe (12.1) which is directly exposed to the cooling fluid (8). [4] Device (12) for detecting a defect in an electrical energy storage device (1) which has a housing (2) in which a plurality of electrochemical cells (4) are arranged which can be cooled directly in the housing (2) by means of an electrically non-conductive cooling fluid (8), characterized by , that at least one conductive measuring probe (12.1) is arranged in the housing (2) which is coupled to a conductivity sensor (12.2) which is configured to measure the electrical conductivity of the cooling fluid (8). [5] Device (12) according to claim 4, characterized by , that at least one conductor track (12.1.1) is arranged in the housing (2) as a conductive measuring probe (12.1). [6] Electrical energy storage device (1) comprising a plurality of cells (4) arranged in a housing (2) and comprising a device (12) according to claim 4 or 5.

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