Device for detecting a thermal event in the traction battery of an electrically powered vehicle

Abstract

The invention relates to a device (100) for detecting a thermal event in a traction battery (10) of an electrically powered vehicle, comprising at least a detection device (30) with a break wire (32) which covers an end face (26) of an opening element (24) of a degassing unit (20) of the traction battery (10) in a closed state (1) of the degassing unit (20), wherein the break wire (32) is interrupted by the opening element (24) in an open state (2) of the degassing unit (20). The break wire (32) is electrically conductive. The detection device (30) includes a control unit (40) with which the break wire (32) is electrically coupled. The control unit (40) is configured to detect an interruption of the break wire (32).

Description

[0001] The invention relates to a device for detecting a thermal event in the traction battery of an electrically powered vehicle.

[0002] Thermal events in the traction batteries of electric vehicles, also known as thermal runaway or thermal propagation, are typically detected and processed by sensors integrated into the battery. However, when the vehicle is neither driven nor charging, the detection system is inactive. Therefore, people inside such a parked vehicle cannot be warned.

[0003] US patent 10960246 B2, for example, discloses a method for responding to a critically dangerous battery condition, in which the battery temperature is continuously monitored by means of at least one temperature sensor.

[0004] US 4134060 A describes a method in which deterioration of a battery's condition is monitored by monitoring cell voltages of cell groups, which are continuously compared with cell voltages of comparable cell groups.

[0005] CN 107176038 B discloses a battery management system which includes a control designed to output an error signal in response to a voltage change rate exceeding a first threshold more than a predetermined number of times over a predefined duration during the discharge of a battery cell.

[0006] WO 2013 / 143736 A1 describes a device for signaling and localizing an atypical operating state on galvanic cells, wherein a line leading from the interior of a preferred lithium-ion battery cell to the outside comprises a means for releasing dyes and / or a means for emitting acoustic or optical signals.

[0007] US 3940679 A describes a battery monitor which monitors battery temperature, battery voltage and battery current.

[0008] One object of the invention is to create an improved device for detecting a thermal event in the traction battery of an electrically powered vehicle.

[0009] The aforementioned problem is solved using the features of an independent claim.

[0010] Favorable embodiments and advantages of the invention will become apparent from the further claims, the description and the drawing.

[0011] According to one aspect of the invention, a device for detecting a thermal event in the traction battery of an electrically powered vehicle is proposed, comprising at least a detection device with a break wire which covers an end face of an opening element of a degassing unit of the traction battery when the degassing unit is closed, wherein the break wire is interrupted by the opening element when the degassing unit is open. The break wire is electrically conductive. The detection device includes a control unit with which the break wire is electrically coupled. The control unit is configured to detect an interruption of the break wire.

[0012] The proposed device can be used in traction batteries that have a degassing unit. These degassing units function like pressure relief valves and have an opening element that is pushed outwards, releasing an opening in the battery wall when the internal pressure in the traction battery rises as a result of a thermal event.

[0013] To detect a thermal event outside of normal driving or charging operations, i.e., when the vehicle is not in operation, the opening of the degassing unit is used as an indicator.

[0014] In the proposed device, the opening of the degassing unit is detected by means of a subsequently applied tear wire. For this purpose, a very thin, electrically conductive wire is attached to the degassing unit in a cross shape and fixed with a carrier strip, for example adhesive tape. The wire is also fixed to the side of the degassing unit.

[0015] An electric current is sent through the wire and detected by a control unit. When the degassing unit opens, the wire is broken and the current flow is interrupted. This is registered by the control unit.

[0016] The control unit can now sound a warning tone and warn the occupants.

[0017] The device offers the advantage of easy retrofitting of existing vehicles. It is simple and inexpensive.

[0018] According to an advantageous embodiment of the device, the breakaway wire can be fixed to the opening element and to a housing of the degassing unit by means of a carrier band. This allows the breakaway wire to be reliably and permanently attached to the degassing unit, preventing it from coming loose even during operation.

[0019] According to an advantageous embodiment of the device, the tear wire can be arranged in a cross shape above the front face of the opening element. This allows the opening of the degassing unit to be reliably detected.

[0020] According to an advantageous embodiment of the device, the carrier band can be arranged on the front face of the opening element, particularly in a cross shape. Alternatively or additionally, the carrier band can be arranged radially around the outside of the degassing unit housing. This allows the breakaway wire to be reliably and permanently attached to the degassing unit, preventing it from coming loose even during operation.

[0021] According to an advantageous embodiment of the device, the control unit can be configured to trigger a warning message, in particular a warning tone, when the break wire is interrupted. This ensures that any persons who may be in the vehicle are reliably warned of an impending danger.

[0022] According to an advantageous embodiment of the device, two tear wires can be arranged crosswise above the front face of the opening element, both of which are electrically coupled to the control unit. It is particularly advantageous to arrange the two tear wires crosswise so that a warning tone is only emitted when both circuits are interrupted.

[0023] According to an advantageous embodiment of the device, the control unit can be configured to trigger the warning message only when both break wires are interrupted. If a wire is torn or broken due to external circumstances, this design prevents a so-called false-positive alarm.

[0024] According to an advantageous embodiment of the device, the break wire can be energized in the closed state. This allows the undamaged state of the break wire to be reliably detected.

[0025] According to an advantageous embodiment of the device, the control unit can be configured to determine the state of the breaking wire resistively or inductively. The undamaged state of the breaking wire can thus be determined by measuring an electric current through the breaking wire or by measuring the inductance of a wire loop.

[0026] According to an advantageous embodiment, the device for retrofitting can be designed to be attached to the degassing unit of the traction battery. This allows existing vehicles to be easily retrofitted with the device.

[0027] Further advantages will become apparent from the following description of the drawings. The drawings illustrate an embodiment of the invention. The drawings, the description, and the claims contain numerous features in combination. A person skilled in the art will expediently consider the features individually and combine them into meaningful further combinations.

[0028] This shows: Fig. 1 a longitudinal section through a device for detecting a thermal event of a traction battery of an electrically powered vehicle according to an embodiment of the invention in a closed state of a degassing unit; Fig. 2 a top view of the device according to Fig. 1; and Fig. 3 a longitudinal section through the device in an open state of the degassing unit.

[0029] In the figures, identical or similar components are numbered with the same reference symbols. The figures merely show examples and are not to be understood as limiting.

[0030] Fig. Figure 1 shows a longitudinal section through a device 100 for detecting a thermal event of a traction battery 10 of an electrically operated vehicle according to an embodiment of the invention in a closed state 1 of a degassing unit 20.

[0031] In Fig. Figure 1 shows a section of a wall 12 of a traction battery 10. A degassing unit 20 is arranged at a degassing opening 18 (not shown).

[0032] The degassing unit 20 has a housing 22 which, in the closed state 1, is equipped with a Fig. The opening element 24, which is not visible, is closed. Towards the outside space 14, the degassing unit 20 has a cover cap 28 as mechanical protection.

[0033] The device 100 for detecting a thermal event in the interior 16 of the traction battery 10 comprises a detection device 30 with a tear wire 32, which covers an end face 26 of an opening element 24 of a degassing unit 20 of the traction battery 10 in the closed state 1 of the degassing unit 20.

[0034] The break wire 32 is electrically coupled to a control unit 40 of the detection device 30. The break wire 32 is electrically conductive and carries current when closed 1.

[0035] The tear wire 32 is fixed to the opening element 24 and to the housing 22 of the degassing unit 20 by means of a carrier band 34. For this purpose, the carrier band 34 is arranged radially around the outside of the housing 22 of the degassing unit 20.

[0036] Fig. Figure 2 shows a top view of the device 100 with the end face 26 of the opening element 24.

[0037] The tear wire 32 is arranged in a cross shape over the front face 26 of the opening element 24. The support band 34 is also arranged in a cross shape on the front face 26 of the opening element 24 to fix the tear wire 32.

[0038] The tearing wire 32 is in an open state 2 of the degassing unit 20, as shown in Fig. 3 is shown, interrupted by the opening element 24.

[0039] The control unit 40 is designed to detect an interruption of the break wire 32 and, in the event of such an interruption, to trigger a warning message, in particular a warning tone. This ensures that persons who may be in the vehicle are reliably warned of a potential danger.

[0040] The control unit 40 can determine the state of the tear wire 32 resistively or inductively, for example by determining an electric current through the tear wire 32 or, if the tear wire 32 is designed as a wire loop, by determining its inductance.

[0041] Advantageous can be, as in Fig. As can be seen, two tear wires 32 are arranged in a cross shape above the front face 26 of the opening element 24, both of which are electrically coupled to the control unit 40. The control unit 40 can then be configured to trigger the warning message only if both tear wires 32 are broken. In this way, false alarms, for example caused by only one broken tear wire 32, can be reliably avoided.

[0042] In Fig. 3 the device is recognizable in an open state 2 of the degassing unit 20.

[0043] The opening element 24 has been moved towards the outer chamber 14, allowing the overpressure in the interior 16 of the traction battery 10 to be released through the degassing opening 18. The break wire 32, located on the end face 26 of the opening element 24, has thereby broken off, so that the current flow through the break wire 32, which is monitored by the control unit 40, is detected as interrupted. This allows the control unit 40 to send an alarm signal.

[0044] Advantageously, the proposed device 100 can be retrofitted to the degassing unit 20 of the traction battery 10. Reference symbol list 10 traction batteries 12 wall 14 Outdoor area 16 Interior 18 Degassing opening 20 Degassing unit 22 cases 24 opening elements 26 Front 28 Cover cap 30 Detection device 32 tearing wire 34 carrier tape 40 Control unit 100 Device 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] US 10960246 B2

[0003] US 4134060 A

[0004] CN 107176038 B

[0005] WO 2013 / 143736 A1

[0006] US 3940679 A

[0007]

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