Means of transport, arrangement, device and method for determining a time for a prophylactic replacement of an electrical component

Abstract

Method for determining a time for a prophylactic replacement of a constantly electrically conductive component (3) comprising the steps: - Determining (100) a continuous usage behavior of the component (3) over time, - Comparing (200) the usage behavior with a predefined reference and in response to a predefined result of the comparison, - Outputting (300) a signal (8) representing the time for the prophylactic replacement, wherein the component (3): - is a fuse, in particular a fuse, and / or - is set up to protect a traction network (12) of an electrically powered means of transport (10).

Description

State of the art

[0001] The present invention relates to a means of propulsion, an arrangement, a device, and a method for determining a time for the prophylactic replacement of an electrically conductive component during operation. In particular, the present invention relates to the indication of the need for the prophylactic replacement of a fuse.

[0002] The electrification of private passenger transport is currently progressing rapidly. One approach involves using high-voltage batteries as energy storage devices in vehicles, which supply electrical energy to electric drive motors. In the event of a fault, very high currents (e.g., 4500 A and more) can be generated by the energy storage system. To protect the traction electrical systems, fuses are used, which normally already have to carry very high currents. These fuses are often in the form of cartridge fuses in high-voltage batteries, which must be dimensioned with a high rated current. To withstand temporarily permissible overcurrents, these cartridge fuses must even be dimensioned for a higher rated current than would actually be desirable in terms of tripping characteristics.Due to the high dynamic load and the comparatively small difference between the rated / nominal current and the required disconnect current, high demands are placed on the correct fuse design throughout the entire service life, taking into account vehicle-specific boundary conditions. In other words, there is a conflict of objectives: the fuse must allow temporarily permissible overcurrents with the lowest possible loss factor, but in the event of a fault, it must also interrupt even higher currents very quickly to protect the traction electrical system. Therefore, in the state of the art, fuses are designed, tested, and manufactured in relatively small quantities for the specific application. The fuse is typically selected with a higher rated current than would actually be necessary in the absence of aging processes, in order to prevent aging from becoming an operational risk for the vehicle.The fuse rating is based on an aging forecast that assumes the fuse will be used at the upper limit of the energy storage device's electrical capacity for its entire specified lifespan. Alternatively, the fuse is replaced according to conservatively (pessimistically) defined maintenance intervals. These intervals do not take into account the actual stress / aging of the fuse.

[0003] DE 10 2010 041 998 A1 discloses a method for predicting the service life of a relay or contactor, in which aging or sticking prevention is determined based on a temperature profile. The aging of contactors is caused in particular by switching operations, which, depending on the frequency and magnitude of the switched electrical power, influence the aging of the current-carrying components. Accordingly, counting the switching operations or determining the power switched in each operation is proposed to predict the service life of the component.

[0004] DE 10 2012 215 063 A1 discloses a monitoring circuit for a contactor in which an aging counter with feedback is integrated into a monitoring circuit. In this way, rapid aging of the contactor can be detected and an overly conservative estimate of the aging state of the monitored contactor can be corrected.

[0005] For permanently live components such as fuses, the methods known in the prior art are not available and would involve unnecessarily high costs for application- / project-specific development. The design method described above is disadvantageous with regard to the dimensioning of further coupled disconnecting elements (packaging and costs) as well as more critical tripping behavior in the event of short circuits. Costs are also driven up with regard to maintenance and servicing, since maintenance intervals are determined based on a pessimistic aging (intensive use) of the respective component, even though the actual driving behavior of the end customer sometimes does not correspond to such intensive use.

[0006] It is therefore an object of the present invention to eliminate the aforementioned disadvantages. Disclosure of the invention

[0007] The problem identified above is solved according to the invention by a method for determining a point in time for the prophylactic replacement of a component that is always electrically conductive. The component therefore does not have a switch, which could, for example, be designed as a relay or a contactor. Furthermore, within the scope of the present invention, prophylactic replacement of the component is understood to mean a process in which the component is replaced despite its continued functionality (e.g., due to aging) in order to ensure continuous reliable operation. In a first step, the continuous usage pattern of the component over time is determined.In the context of the present invention, "continuous" usage behavior is understood to mean, in particular, the determination of a flux quantity, preferably independently of the determination or detection of a switching operation or a discontinuous change in an electrical operating characteristic of the component. Of course, continuous usage behavior can be determined by randomly sampling characteristic values ​​at different times. In other words, it is not necessary for continuous determination of usage behavior. Rather, the determination can be carried out at predefined times or when predefined limit values ​​of the monitored characteristic are reached during the operation of the component. In particular, no switching operations or electrical characteristic values ​​during discontinuous operating situations are counted or treated or integrated separately as such.The usage pattern is then compared to a predefined reference. Since usage patterns can influence the aging process, a characteristic value associated with the usage pattern can be read from memory and compared to the determined usage pattern as a predefined reference. The reference can thus be assigned a characteristic value for a predefined aging state. If a predefined relationship between the usage pattern and the reference is determined, a signal representing the time for preventative replacement is output. This output can be directed specifically to the user of a vehicle containing the component. The signal could, for example, indicate a visit to a workshop, the expiration of a maintenance interval, or similar events.Alternatively or additionally, the signal can generate a fault memory entry to allow for the replacement of the progressively aged component during a future inspection. As a result, the fuse sizing can be more closely aligned with the tripping scenario. Furthermore, the other components can be designed with less oversizing. Premature failure of the drivetrain, including the component, can be avoided by determining the actual aging of the component and indicating its potential replacement in a timely manner.

[0008] The dependent claims describe preferred embodiments of the invention.

[0009] The usage pattern can, for example, characterize the current load on the component. In other words, the currents carried by the component can be determined over time and summed according to a predefined rule. This rule defines the (de)use of the component based on the current load. Similarly, the component's temperature, or a temperature corresponding to the component's temperature, can be determined and used to assess its aging state. In particular, considering both the electrical energy carried and the temperature load can provide a highly accurate representation of the component's actual aging state. Other quantities representing the electrical energy carried by the component can also be determined.For example, if the electrical resistance is known, a voltage measurement can be used to determine the heat generation and current load of the component. The determination of usage behavior can be carried out over several operating cycles and, beyond that, over significantly longer periods. In particular, the determination of usage behavior starts immediately after the initial commissioning of a means of transport designed according to the invention and ends with the output of the signal, or with the actual replacement of the component, or with a reset of the interval for determining usage behavior initiated by maintenance personnel. Thus, several days, weeks, months, or even years can pass before the usage behavior determined according to the invention is available for reference in a predefined manner and the proposed signal is output.

[0010] The reference data can be stored, for example, in the form of a characteristic map representing the component's aging process as a function of its usage. In particular, the aging in this map can be quadratically dependent on the current flowing through the component. The current, or its square, can preferably be integrated to determine a characteristic value for usage behavior that is proportional to the aging state. Temperature can also be considered in the characteristic map. Specifically, temperature can also have a quadratic influence on the characteristic value for usage behavior.

[0011] The component can, for example, be a fuse (e.g., a cartridge fuse) through which, during normal operation, electrical energy flows to power a means of transport, carrying currents up to 500 amperes and short-circuit currents up to 10,000 amperes. Alternatively or additionally, the component can be designed to protect the traction network of an electrically powered means of transport. The electrical energies carried by these components cause them to age relatively quickly, so that replacing the component according to the invention, in response to the output signal, can lead, on the one hand, to high operational reliability and, on the other hand, to a design of the components of the traction network that better meets the actual requirements.

[0012] The signal can be issued, for example, during normal operating conditions of the component or means of transport, even without unusual stress. In other words, the signal is not issued in a state where a failure is particularly likely, imminent, or has already occurred. Rather, the signal is issued specifically when it does not significantly distract the addressed user from important or even safety-relevant tasks. As described above, the signal can also trigger the creation of an error log entry, which is not immediately detected by the user but only by maintenance personnel who may be called in.

[0013] In one embodiment of the present invention, a remaining service life prediction is proposed based on measurement data (in particular current and temperature) already collected during operation for other functions of the battery management system (BMS). This allows the high-voltage fuse to be replaced at the latest possible time within the vehicle's maintenance concept, without causing unnecessary tripping or component failures. The proposed method generally enables the use of smaller (and therefore less expensive and less bulky) high-voltage components. The load-based maintenance achieved in this way prevents customer-experienced failures without generating unnecessary costs.

[0014] For this purpose, the BMS can use current and, if applicable, relevant temperature data to determine the remaining service life of the high-voltage component based on a wear model. For the high-voltage fuse considered here, this essentially applies the rated currents and temperature influences to the corresponding melting integral, specific to the usage. If the predicted remaining service life falls below a value defined within the maintenance concept, the end customer is prompted to visit the workshop. There, the affected component can be replaced at a suitable time. This prevents the fuse from blowing or the component from failing during operation or at a particularly inconvenient time for the user.

[0015] According to a second aspect of the present invention, a device for determining a time for the prophylactic replacement of an electrical and / or electronic component is proposed. The device comprises a detection unit configured to determine the component's usage behavior over time. The detection unit can, for example, include a thermometer and / or a current sensor and / or a voltage sensor and can thus also be understood as a sensing unit. Furthermore, the device comprises an evaluation unit (e.g., a microcontroller, a programmable processor, a nanocontroller, or similar) configured to compare the usage behavior with a predefined reference. For this purpose, the evaluation unit can be connected to a data storage device that provides the reference as well as instructions for carrying out the method according to the first aspect of the invention.An output unit is configured to output a signal representing the time for prophylactic replacement in response to a predefined result of the comparison performed by the evaluation unit. The output unit can, for example, include a display device (e.g., a screen, a head-up display, etc.) and / or a loudspeaker. Naturally, the output unit can also have a wireless interface for communication with a wireless user device, by means of which the signal provided according to the invention can be presented to the user. Alternatively or additionally, the output unit can be linked to an error memory, which receives a corresponding error entry when it receives the signal proposed according to the invention.In this way, the device according to the invention is configured to carry out the steps of a method according to the first-mentioned aspect of the invention, which is why the features, combinations of features and the advantages resulting therefrom are correspondingly evident, so that reference is made to the above statements to avoid repetition.

[0016] According to a third aspect of the present invention, an arrangement is proposed comprising a device according to the second aspect of the invention and a component monitored by the device (e.g., a fuse, in particular a fusible link). The arrangement can be intended for use and / or protection in a traction electrical system of a means of transport.

[0017] According to a fourth aspect of the present invention, a means of transport (e.g., a car, a van, a truck, a motorcycle, an aircraft and / or watercraft) is proposed, which comprises a device according to the second aspect of the invention and, alternatively or additionally, an arrangement according to the third aspect of the invention. The latter two aspects of the invention also realize the features, combinations of features, and advantages corresponding to the first aspects of the invention. Brief description of the drawings

[0018] Exemplary embodiments of the invention are described in detail below with reference to the accompanying drawings. The drawings show:

[0019] Fig. 1 a schematic view of components of an embodiment of an electrically driven means of transport according to the invention with an embodiment of an arrangement according to the invention;

[0020] Fig. 2 a detailed view of components of an embodiment of an arrangement according to the invention; and

[0021] Fig. 3 A flowchart illustrating the steps of an embodiment of a method according to the invention for determining a time for a prophylactic replacement of a component that is always electrically conductive. Embodiments of the invention

[0022] Fig. 1 shows a car 10 as a means of transport which uses a traction on-board network 12 as an arrangement according to the invention. The traction electrical system 12 features an electric drive machine 1 which consist of an electrochemical energy storage device 2 is supplied with traction energy.

[0023] Fig. 2 shows components of a Fig. 1 overview of the traction on-board network 12, whose electrochemical energy storage 2 has been extended by components of a device according to the invention, all of which are housed in a casing 13 of the electrochemical energy storage 2 are housed. To manage the energy flows between cells 14 and the electric drive motor 1 A fuse is used to protect against excessively high currents. 3 It is designed as an electrical component that interrupts the electrical connection upon reaching a predefined disconnection current. Since the fuse... 3 Naturally subject to an aging process that causes the current-carrying capacity and switching current level to decrease over time, a temperature sensor 9 and a current sensor 11 an investigative unit equipped with an electronic control unit in the form of a battery management system (BMS) 4connected as an evaluation unit. The BMS 4 is equipped with a loudspeaker in terms of information technology 7 linked, via which it transmits sound signals 8 can output. Another element of the output unit is a screen. 6 provided which is also connected to the electronic control unit in terms of information technology 4 is connected. A data storage device 5 is connected to the electronic control unit in terms of information technology 4 connected and provides a reference for assessing usage behavior and instructions for carrying out the inventive method.

[0024] Fig. Figure 3 shows steps of an embodiment of a method according to the invention for determining a time for a prophylactic replacement of a component that is always electrically conductive. In step 100A continuous usage pattern of the component, in the form of a current flow, is determined, at least during those times when a vehicle containing the component is in operation. Additionally, the operating-related temperature increase of the component is determined and taken into account when determining the usage pattern. In step 200 The usage behavior is compared with a predefined reference from a data store, and in response to a predefined result of the comparison, in particular reaching a threshold value marked by the reference in step 300A signal representing the time for preventative replacement is output via a loudspeaker and a screen. Furthermore, an error entry is stored in the data memory, specifying the component and a recommended replacement time. In this way, the components contained in a traction electrical system according to the invention can be designed to better correspond to the actual stresses caused by the operation of the electrical system. Unnecessary weight, unnecessary costs, and unnecessary energy consumption during the operation of a means of transport equipped according to the invention can thus be avoided. Moreover, maintenance costs (inspection, etc.) can be reduced, since the component is only replaced when necessary.

[0025] Even though the aspects of the invention and advantageous embodiments have been described in detail with reference to the exemplary embodiments explained in conjunction with the accompanying drawing figures, modifications and combinations of features of the illustrated exemplary embodiments are possible for the person skilled in the art without leaving the scope of the present invention, the scope of protection of which is defined by the accompanying claims. Reference symbol list 1 Electric drive motor 2 Electrochemical energy storage 3 fuse 4 BMS 5 Data storage 6 screen 7 speakers 8 Tone signal 9 Temperature sensor 10 cars 11 Current sensor 12 Traction on-board network 13 cases 14 Electrochemical cells 100–300 process steps QUOTES INCLUDED IN THE DESCRIPTION

[0026] 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

[0027] DE 102010041998 A1

[0003] DE 102012215063 A1

[0004]

Claims

[1] Procedure for determining a point in time for a prophylactic replacement of a component that is always electrically conductive ( 3 ) comprising the steps: - Determine ( 100 ) a continuous usage behavior of the component ( 3 ) over time, - Compare ( 200 ) of usage behavior with a predefined reference and in response to a predefined result of the comparison - Spend ( 300 ) of a signal ( 8 ) representing the timing for prophylactic replacement. [2] The method of claim 1, wherein the usage behavior - a current load and / or - a temperature load and / or – one for the component ( 3 ) transported electrical energy proportional size the component ( 3 ) describes. [3] The method of claim 1 or 2, wherein the usage behavior - over several operating cycles, in particular over several – days and / or – weeks and / or – months and / or – Years analyzed and / or – during operation of the component ( 3 ) is determined at regular intervals and compared with the reference. [4] The method according to any one of the preceding claims, wherein the reference describes a characteristic map which an aging process of the component ( 3 ) as a function of usage behavior. [5] The method according to any one of the preceding claims, wherein the component ( 3 ) - A fuse, in particular a fuse, is and / or – to secure a traction network ( 12 ) of an electrically powered means of transportation ( 10 ) is set up. [6] The method according to any one of the preceding claims, wherein the signal ( 8 ) in a normal operating state of the component ( 3 ) is issued without exceptional stress. [7] The method according to any one of the preceding claims, wherein the signal ( 8 ) to a user of a means of transportation ( 10 ) is issued. [8] Device for determining a point in time for a prophylactic replacement of an electrical and / or electronic component ( 3 ) full: – a determination unit ( 9 , 11 ) which are used to determine usage behavior of the component ( 3 ) is set up over time, – an evaluation unit ( 4 ), which is set up to compare usage behavior with a predefined reference and – an output unit ( 6 , 7 ), which is arranged to emit a signal ( 8 ) representing the point in time for the prophylactic exchange. [9] Arrangement comprising - a device according to claim 8 and - a component monitored by the device ( 3 ), especially a fuse. [10] means of locomotion comprising - a device according to claim 8 and / or - an arrangement according to claim 9.

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