Method for diagnosing a battery of a vehicle, device, computer program product and vehicle

Abstract

Disclosed is a method for diagnosing a battery (3) of a vehicle (1), comprising the steps of monitoring (S21, S31) a temperature of the battery (3) and determining (S22, S32) whether the temperature exceeds a predefined threshold temperature. The method further comprises the step of determining (S23, S33) a duration of one or more periods during which the temperature exceeds the threshold temperature in response to determining that the temperature exceeds the predefined threshold temperature. Furthermore, a device (2), a computer program product and a vehicle (1) are disclosed which are related to the method.

Description

[0001] The invention relates to a method for diagnosing a battery of a vehicle, comprising the steps of monitoring a temperature of the battery and determining whether the temperature exceeds a predefined threshold temperature.

[0002] The invention further relates to a device which is designed to carry out the method.

[0003] Furthermore, the invention relates to a computer program product comprising instructions which, when the program is executed by a processor, cause the processor to carry out the method.

[0004] Furthermore, the invention relates to a vehicle comprising the device.

[0005] It is generally known that a vehicle battery must not be operated above certain predefined threshold temperatures, as otherwise the battery's operational reliability may be compromised or, at the very least, its service life may be shortened. The respective threshold temperature may vary for different batteries.

[0006] In this regard, a method for managing an energy storage system of a vehicle is known from US 2022 / 0161682 A1. It provides for monitoring the temperature of a battery using a sensor unit. A control unit of the vehicle is configured to deactivate a battery pack assembly of the energy storage system or to throttle its power if the battery temperature exceeds a safety temperature level.

[0007] Temperature measuring strips from DeltaTrak®, Pleasanton, CA, USA, for example model 51056, are known from other technical fields, such as food and drug storage.

[0008] It is the object of the invention to provide a method for diagnosing a battery of a vehicle, a device, a computer program product and a vehicle of the type mentioned at the outset, which are improved over the prior art.

[0009] The above object is achieved by a method for diagnosing a battery of a vehicle having the features of independent patent claim 1, by a device having the features of independent patent claim 5, by a computer program product having the features of independent patent claim 9, and by a vehicle having the features of independent patent claim 10.

[0010] Further features and details of the invention emerge from the dependent claims, the description, and the drawings. Features and details described in connection with the method according to the invention naturally also apply in connection with the device according to the invention, the computer program product according to the invention, and the vehicle according to the invention, and vice versa, so that with regard to the disclosure of the individual aspects of the invention, reference is always made to each other.

[0011] According to the invention, the method comprises the step of determining a duration of one or more periods during which the temperature exceeds the threshold temperature in response to determining that the temperature exceeds the predefined threshold temperature.

[0012] The invention is based on the finding that it may not only be important to determine whether the predefined threshold temperature is exceeded by the battery temperature, but also to know for how long the predefined threshold temperature has been exceeded. Battery aging processes are triggered prematurely, in particular, when the predefined threshold temperature assigned to the battery, which cannot be reached during everyday use, is exceeded for a corresponding period of time. If this period is not reached, no premature aging is to be expected; otherwise, the battery may age prematurely.

[0013] For example, malicious vehicle owners could intentionally heat the battery to abnormally high temperatures shortly before the expiration of a warranty period, causing it to exceed the threshold temperature and prematurely age the battery. They could then file a warranty claim with the vehicle or battery manufacturer, such as a free replacement within the warranty period. However, if the procedure proposed here has determined the period for which the battery temperature exceeded the threshold temperature, the manufacturer can defend against such artificially induced warranty claims by arguing that the vehicle owner intentionally heated the battery above the threshold temperature for a certain, inadmissible period and is thus responsible for the premature ageing of the battery.The method thus advantageously enables the manufacturer of the battery or vehicle to reduce the effort and costs associated with intentionally induced premature battery aging, which can be caused by exceeding the threshold temperature.

[0014] Advantageous embodiments of the invention are part of the dependent claims and described in the description.

[0015] The threshold temperature can be between approximately 40°C and 80°C, in particular between 55°C and 65°C. A preferred threshold temperature is 60°C. Many batteries show premature aging signs if they are exposed to temperatures above 60°C for an extended period. Since 60°C and above are not reached in everyday life, even on hot summer days, it can be concluded with a high degree of probability that the battery has been intentionally tampered with if it is determined that the battery has been exposed to temperatures above the threshold temperature of 60°C for an extended period. The method can therefore determine whether the battery has been tampered with if the duration exceeds a permissible maximum duration. In particular, the maximum duration can be one or more hours, such as 1, 3, or 5 hours, or one or more days, such as 2, 5, or 7 days, depending on the type of battery.It is preferred that the threshold temperature of 60°C be assigned a maximum duration of 24 hours for exceeding the threshold temperature. However, significant aging effects in some batteries only become apparent after two or more days or weeks of exceeding the threshold temperature, so maximum durations of between two days and several weeks are provided in some embodiments.

[0016] In some embodiments, the battery is a vehicle's traction battery, such as a 400-volt traction battery or an 800-volt traction battery. In this case, it can generally be a high-voltage battery (HV battery) for vehicles. However, it can also be another type of battery, such as a vehicle's auxiliary battery, which can provide voltages of 12 volts, 24 volts, or 48 volts. However, the problem, particularly with traction batteries in fully electric or hybrid vehicles, is that replacing them in the event of damage is associated with high costs, so the method can be used with particular advantage here.

[0017] In embodiments, the method comprises the method step of determining the duration using a first point in time at which the temperature crosses the threshold temperature upwards and a second point in time at which the temperature crosses the threshold temperature downwards, wherein the second point in time follows the first point in time and the first point in time defines a lower limit of a period and the second point in time defines an upper limit of the period. In this way, the duration can be determined particularly easily, for example, by calculating the difference between the first point in time and the second point in time. The method can comprise accumulating multiple periods to determine the duration.For this purpose, for example, a third and a fourth time point can be determined, which follow the second time point and are consecutive, in order to determine a further period limited by the third and fourth time points and during which the threshold temperature is again exceeded. In such embodiments, the duration can be determined as the sum of the duration of the period and the further period and, if applicable, further subsequent periods. Therefore, the method preferably comprises the step of accumulating individual durations of two or more periods in which the threshold temperature is exceeded to determine a total duration.

[0018] Determining whether the temperature exceeds the predefined threshold temperature can occur simultaneously with the temperature monitoring or after a specified time has elapsed for a previous period. This means that it is possible to first record a temperature profile over the period, preferably continuously, and only after the end of this period, which can span an extended period such as several hours, days, weeks, or months, determine from the temperature profile whether the threshold temperature has been exceeded. Thus, determining whether the threshold temperature has been exceeded does not have to occur immediately during temperature monitoring, but can take place later, which can conserve resources.This makes it possible, in particular, to initially record the temperature curve only in the vehicle and to read it out at a later point in time, such as during a workshop visit, in order to determine, with a time delay to the monitoring of the battery temperature, whether the temperature has exceeded the predefined threshold temperature and, if so, for what duration this was the case.

[0019] Furthermore, embodiments of the method provide for determining immediately during temperature monitoring whether the temperature exceeds the predefined threshold temperature, but only determining the duration of the exceedance after a time delay from a temperature profile recorded during monitoring. If it is determined that the temperature has exceeded the threshold temperature, this is preferably initially recorded only by setting a flag in an error log of the vehicle. The duration can then be determined subsequently. This means that the subsequent determination of the duration can be omitted, for example during a workshop visit, provided that no exceedance of the threshold temperature was detected during temperature monitoring, i.e. the flag was not set in the error log, which can also conserve resources.

[0020] Some embodiments provide for permanent storage of the specified duration. "Permanent" here can mean using a non-volatile memory, which is preferably protected against tampering. Therefore, the storage can preferably not be reversed. A preferred memory is a write-once memory. The memory can be an electronic memory. It can be a memory chip. Preferably, the electronic memory is protected against overwriting and / or erasure. This can be achieved by setting a write-protection bit in the electronic memory.

[0021] However, the storage device can also be a chemical storage device that irreversibly changes a property, such as an optical property, when the threshold temperature is exceeded. The chemical storage device can comprise a chemical substance that changes its property. Preferably, the chemical storage device changes its color when the threshold temperature is exceeded, in particular permanently and irreversibly. It is preferred that the chemical storage device only changes its property after a predefined period of time in which the threshold temperature is exceeded. The predefined period can depend on a model or type of battery. It is particularly preferred that the chemical storage device has several sections and changes its property section by section along a time scale when the threshold temperature is exceeded for different periods. Section by section can mean in particular continuously or step by step.In particular, the duration for which the temperature has cumulatively exceeded the threshold temperature can be read off the chemical substance of the device's chemical storage, preferably on the time scale. Suitable chemical substances are known from the fields of medical technology and food technology, where they are used in time-temperature indicators. However, these serve, for example, to determine whether a storage temperature of an object, such as the freezing point in some medical devices or foodstuffs, has been exceeded.

[0022] Alternatively or additionally, the duration of one or more periods can be temporarily stored. This can be done, for example, on a display in a driver's cab of the vehicle. This may be sufficient to alert a driver of the vehicle that the threshold temperature has been exceeded, particularly if the exceedance is not a critical duration that could damage the battery, i.e., the duration falls below a threshold or maximum duration assigned to the battery before artificial aging of the battery can be caused.

[0023] Some embodiments provide for transmitting the determined duration via an interface to a memory located remotely from the vehicle or to a remote display. These can be located, in particular, at a battery or vehicle manufacturer's or a workshop's premises. This can make manipulation of the determined duration more difficult than storing it in the results memory onboard the vehicle.

[0024] In some embodiments, temperature monitoring is performed independently of the battery's operating state. In particular, monitoring may be performed continuously in all battery operating states. Thus, battery tampering can be determined at any time. However, other embodiments provide for monitoring to be performed only when the vehicle and / or battery are off. This allows resources for temperature monitoring to be saved. The most likely time for the battery's temperature to be tampered with is when the vehicle is off, since it is very unlikely that the required temperatures will be reached while driving.In particular, temperature monitoring can be carried out independently of the operating state of the battery if the method can be carried out independently of the voltage provided by the battery, i.e. if it can be carried out by feeding it with an auxiliary battery, such as a button cell, or passively, without supplying electrical voltage.

[0025] Furthermore, the object of providing a device that is improved over the prior art is achieved by the device according to claim 5, as described below. The device enables the advantages described above in connection with the method to be achieved, to which reference is hereby made to avoid repetition.

[0026] The device may comprise a result memory for preferably permanently storing the determined duration. The device may include an electrical circuit, preferably configured to perform the determination of the duration by software or hardware. Alternatively, the device may comprise a chemical substance configured to perform the determination of the duration of the one or more time periods by a chemical process. In an embodiment in software or hardware, preferably the determination of the duration may be stored by a bit change in the result memory. In an embodiment providing a chemical substance, preferably the determination of the duration may be stored by a color change of the chemical substance in the result memory. Various such embodiments are discussed below.Instead of the result storage, an interface may be provided to permanently or temporarily store or display the duration away from the vehicle.

[0027] The device can, in particular, be a data processing device comprising a processor configured to execute the method. The processor can be embodied in an application-specific integrated circuit (ASIC), or the ASIC can comprise the processor. In some embodiments, the ASIC can be integrated into a cell management controller (CMC) of the vehicle. A software-supported embodiment of the method can be achieved using an ASIC. Such ASICs for determining battery temperature are already present in many vehicles and only need to be programmed for the new task. This can be done quickly and cost-effectively.

[0028] In some embodiments, the device comprises a triggering device configured to cause the device to determine the duration when the temperature exceeds the threshold temperature. Thus, the device itself can detect when and until the period of the exceedance.

[0029] Preferably, the determination is performed by software, such as by the data processing device. Thus, it is preferred that software determines the duration. The ASIC of the data processing device may be in electrical connection with one or more temperature sensors of the CMC for this purpose. The temperature sensors may be arranged to determine the temperature. The ASIC may include a software comparator, which is a preferred triggering device. The software comparator may have a first input connected to the temperature sensor. The software comparator may have a second input configured to receive the threshold temperature or a corresponding quantity, such as a corresponding voltage, from the ASIC via software.The software comparator can include an output to trigger an interrupt if a comparison of the first input and the second input shows that the threshold temperature has been exceeded. The software comparator can be configured to trigger another interrupt with the output if a comparison of the first input and the second input shows that the threshold temperature has been exceeded again. The software comparator can thus control the determination of the duration.

[0030] The CMC may include or be electrically connected to the result memory. The interrupt may cause the duration of the one or more periods during which the temperature of the battery exceeds the threshold temperature to be stored in the result memory, preferably permanently stored therein, in response to a determination by the software comparator that the temperature exceeds the predefined threshold temperature. In particular, the interrupt may trigger the commencement of storing the duration in the result memory. In particular, the further interrupt may trigger the completion or at least interruption of storing the duration in the result memory.

[0031] A further embodiment provides that the determination is performed by hardware, in particular by electrical components of the device. The device can contain a hardware comparator. The hardware comparator is a further preferred triggering device. The hardware comparator preferably comprises, like the software comparator, the first input, the second input, and the output. The hardware comparator differs from the software comparator in that it is not integrated in the ASIC and the threshold temperature or a corresponding value, such as a voltage, is provided to the second input of the hardware comparator not by software, but by hardware. The hardware comparator is therefore a preferred electrical component in the device, preferably in the CMC.

[0032] Another embodiment that enables the duration to be determined by hardware provides a threshold temperature sensor, also called a temperature threshold sensor, as an electrical component. The threshold temperature sensor can be connected upstream of the result memory, if provided. The threshold temperature sensor can be connected between the temperature sensor and the result memory. The threshold temperature sensor can be a temperature switch. It can be a temperature switch such as a Sensata Airpax 6700. The temperature switch can be configured to close the device's electrical circuit when the threshold temperature is exceeded, in order to generate an interrupt that causes the duration of the time period(s) to be determined and, if necessary, stored in the result memory.The temperature switch is preferably passive and triggers the downstream result memory, which records the duration of the threshold violation. If the threshold temperature sensor detects that the temperature has fallen below the threshold again, it can open, i.e., interrupt, the electrical circuit, thus interrupting the determination of the duration or even the storage of the determined duration. This embodiment has the advantage that no ASIC or CMC is required for its implementation. However, it can also be implemented in the CMC.

[0033] Another embodiment that enables the duration to be determined by hardware provides a thermal fuse as an electrical component. The thermal fuse can be connected upstream of the result memory, if one is provided. The thermal fuse can be connected between the temperature sensor and the result memory. The thermal fuse can be configured to interrupt the electrical circuit of the device when the threshold temperature is exceeded, in order to cause the duration of the time period(s) to be determined and, if necessary, stored in the result memory. The thermal fuse can be a thermal fuse from the DF series. This embodiment has the advantage that a triggered or blown thermal fuse clearly indicates that the threshold temperature has been exceeded.The device's electrical circuit is thus permanently interrupted after the thermal fuse blows until it is replaced, for example, by a repair shop. The manufacturer can then assume that the threshold temperature has only been exceeded since the thermal fuse blows, which can be stored as the duration of the period in the result memory.

[0034] It is preferred that the device is operated independently of the operating state of the battery whose temperature is to be monitored. However, the power supply of the device is preferably located within the battery system to be monitored. It is preferably provided, for example, by the battery whose temperature is to be monitored itself or by a button cell in addition to the battery to be monitored. A preferred embodiment provides that the device is operable by the battery to be monitored itself, particularly if the device is integrated into the CMC. The device can be powered by an emergency power battery of the vehicle. Alternatively, the device can be powered by a button cell.In embodiments, the device is powered by an auxiliary battery of the vehicle, such as a 12-volt, 24-volt, or 48-volt auxiliary battery provided in the vehicle in addition to a battery whose temperature is to be monitored, such as a traction battery. Thus, the device can continue to operate even if, for example, the battery to be monitored is disconnected.

[0035] The device can have a temperature-dependent resistor as the temperature sensor(s), which is connected to an input of the triggering device. A low-voltage DC / DC converter can be connected upstream of the triggering device if the device is to be powered by an HV battery. A series resistor can be connected between the low-voltage DC / DC converter and the triggering device. The temperature sensor and the first input of the hardware comparator or the software comparator can be connected to an output of the series resistor. It is preferred that the low-voltage DC / DC converter converts a high voltage, such as 400 or 800 volts, to a low voltage, such as in particular 12 volts, for the triggering device.Electrical circuits such as those of the device, which, as discussed above, may contain ASICs or comparators, are typically operated not at high voltage, but at low voltage, such as preferably 12 volts or even 24 volts. If, as in some embodiments, multiple temperature sensors are present for measuring the temperature of the battery, for example, one temperature sensor per battery cell, the above electrical circuit can be provided separately for each temperature sensor.

[0036] In an alternative device, the determination of the one of the plurality of time periods is not carried out by an electrical circuit that carries out the determination of the duration by hardware or software, but by a chemical substance that is configured to carry out the determination of the duration of the one or more time periods by a chemical process.

[0037] For these embodiments, it is preferred that the device comprises a carrier sheet comprising the chemical substance configured to determine the duration of the one or more periods during which the temperature exceeds the threshold temperature. The carrier sheet may comprise paper or a plastic film. The carrier sheet may in particular be designed as a rectangular or round sheet. The carrier sheet may have a first surface and a second surface opposite the first surface. The chemical substance is preferably arranged on the first surface. An adhesive is preferably applied to the second surface. It may be provided that the carrier sheet is arranged either directly on the battery, for example a housing of the battery, or at least in the vicinity of the battery in order to determine the temperature of the battery.The chemical substance may be designed to change one or more of its properties in a temperature-dependent manner as soon as the threshold temperature is exceeded, such as an optical property, in particular a color.

[0038] A time scale is preferably arranged in the vicinity of the chemical substance, which time scale preferably indicates periods of weeks, days, minutes or hours. Particular preference is given to periods of one or more days. It is preferred that the chemical substance changes the property as time progresses along the time scale in order to determine and preferably permanently store the duration of the one or more periods during which the temperature exceeds the threshold temperature. This can be achieved by the property changing section by section along the time scale, such as continuously or step by step. The chemical substance can accordingly be arranged such that it changes its property at a 1-day marker after one day, at a 2-day marker after two days, and so on. The change in the property of the chemical substance is preferably irreversible.In particular, the substance changes colour when the threshold temperature is exceeded, preferably in sections along the time scale with increasing duration of the one or more time periods, and remains coloured in an already coloured section when the temperature of the battery drops below the threshold temperature again.

[0039] This embodiment has the advantage that it is easy to retrofit, and the device can be manufactured in large quantities and stored in a small space. Such a temperature measuring strip or time-temperature indicator, as proposed in this embodiment, can also be relatively easily made tamper-proof by configuring the carrier sheet to tear upon removal from its intended location or otherwise make tampering with the device visually detectable. Furthermore, this embodiment of the device is passive and does not require an electrical power supply, such as from the traction battery or a separate auxiliary battery.Even if temperature measuring strips are known from other fields, the chemical substance must first be adapted to the present application, as known temperature measuring strips are not designed for the threshold temperatures and durations that need to be monitored and possibly stored in vehicle batteries. However, with knowledge of the present invention, this represents a reasonable experimental effort for the person skilled in the art.

[0040] Furthermore, the object of providing a computer program product which is improved over the prior art is achieved by the computer program product according to claim 9, which comprises instructions which, when the program is executed by a processor, cause the processor to carry out the method described above, as described below.

[0041] The computer program product may be an electronic or optical data storage device, such as a memory chip, a magnetic memory, or an optical memory. The vehicle may include the computer program product. Instructions stored on the computer program product may cause the processor to diagnose the vehicle's battery in such a way that the advantages explained in connection with the method are achieved. The device may include the computer program product. The computer program product may be part of the device for data processing. In particular, the computer program product may be part of a microcontroller or ASIC. The computer program product may contain firmware for the microcontroller or ASIC. Alternatively, the computer program product may contain software for the microcontroller or ASIC.

[0042] Furthermore, the object of the invention to provide a vehicle of the type mentioned at the outset which is improved over the prior art is achieved by the vehicle according to claim 10, as described below.

[0043] According to the invention, the vehicle comprises the device described above. As a result, it is configured to carry out the method described above and achieve its advantages for the vehicle.

[0044] A preferred vehicle is a wheeled motor vehicle. It may be a motor vehicle with an internal combustion engine and / or an electric motor. It may be a 1-, 2-, 3-, 4-, 5-, or 6-seat motor vehicle. In principle, the invention may be particularly relevant for all vehicles in which determining the duration of the battery temperature being exceeded is advantageous. Determining the duration and storing the determined duration, where provided, may be performed via the vehicle's electrical system. However, the vehicle is not limited to motor vehicles.

[0045] Embodiments of the invention are explained in more detail with reference to the drawings and the following description. They show schematically: Fig. 1 shows an embodiment of the vehicle according to the invention, which has a device according to the invention which is designed to carry out a method according to the invention; Fig. 2 shows a first embodiment of a method according to the invention; Fig. 3 shows a second embodiment of a method according to the invention; Fig. 4 shows a first embodiment of the device according to the invention; Fig. 5 shows a second embodiment of the device according to the invention; Fig. 6 shows a third embodiment of the device according to the invention; Fig. 7 shows a fourth embodiment of the device according to the invention; and Fig. 8 a fifth embodiment of the device according to the invention.

[0046] Fig. Figure 1 shows an embodiment of the vehicle 1 according to the invention, which has a device 2 according to the invention, which is designed to carry out a method according to the invention. The device 2 is designed to carry out the method described below with reference to Fig. 2. The vehicle 1 has a battery 3. The device 2 is attached to the battery 3. Depending on the device 2, the device 2 can be glued, plugged, or screwed to the battery 3, for example. The battery 3 is a drive battery of the vehicle 1.

[0047] Fig. 2 shows a first embodiment of the method according to the invention. It is a method for diagnosing the battery 3 of the vehicle 1. In a first step S21, a temperature of the battery 3 is monitored. A step S22 provides for determining whether the temperature exceeds a predefined threshold temperature. A step S23 provides for determining a duration of one or more periods during which the temperature exceeds the threshold temperature in response to a determination that the temperature exceeds the predefined threshold temperature. The first embodiment of the invention is based on the recognition that it may not only be important to determine whether the predefined threshold temperature is exceeded by the temperature of the battery 3, but also to know for how long the predefined threshold temperature has been exceeded.The threshold temperature is 60°C by way of example in all embodiments shown, but can also be higher or lower depending on the type of battery 3. In some embodiments, the invention is embodied in a computer program product comprising instructions that, when executed by a processor 4, cause the processor 4 to execute the method of [the method]. Fig. 2 or in other embodiments.

[0048] Fig. Figure 3 shows a second embodiment of the method according to the invention. This is a further method for diagnosing the battery 3 of the vehicle 1, which, compared to the first embodiment, Fig. 1 is expanded. In a first step S31, a temperature of the battery 3 is monitored. The temperature is monitored independently of an operating state of the battery 3. Here, the monitoring is carried out continuously and without interruption, for example, in order to be able to detect an exceeding of the threshold temperature even when the battery 3 is disconnected or the vehicle 1 is parked. A step S32 provides for determining whether the temperature exceeds a predefined threshold temperature. A step S33 provides for determining a duration of one or more time periods during which the temperature exceeds the threshold temperature in response to a determination that the temperature exceeds the predefined threshold temperature.The duration is determined in step S33, for example, using a first point in time at which the temperature crosses the threshold temperature upwards and a second point in time at which the temperature crosses the threshold temperature downwards, wherein the second point in time follows the first point in time and the first point in time defines a lower limit of a time period and the second point in time defines an upper limit of the time period. By way of example, further time periods in which the temperature of the battery 3 exceeds the threshold temperature are subsequently determined in a similar manner. In a step S34, the determined duration is permanently stored. This can take place within the device 2, but also outside the device 2. The determined duration is therefore stored in the device 2 in a non-erasable manner.In this example, each individual period of duration is stored in the device 2 as soon as it has been determined, and the duration of all periods results cumulatively from the non-erasably stored individual periods.

[0049] Fig. Figure 4 shows a first embodiment of the device 2 according to the invention. The device 2 is a data processing device comprising a processor 4 configured to carry out the method according to Fig. 1 and Fig. 2. By way of example, the device 2 is a cell management controller (CMC) of the vehicle 1. The processor 4 is implemented as an ASIC. The device 2 comprises a triggering device 5 which is configured to cause the device 2 to determine the duration when the temperature exceeds the threshold temperature. A result memory 6 is arranged outside the device 2, for example in a control unit (not shown) of the vehicle 1. The duration can be permanently stored in the result memory 6. For this purpose, the result memory 6 is protected against overwriting and deletion. The battery 3 here is, by way of example, a 400 volt HV battery.

[0050] The triggering device 5 is according to the first embodiment of Fig. 4 a software comparator having a first comparator input 7, a second comparator input 8, and a comparator output 9. The device 2 further comprises a temperature sensor 10 and a series resistor 11. A resistance input 12 of the series resistor 11 is electrically connected to a low-voltage DC / DC converter 13 external to the device 2. The device 2 is powered by the battery 3, whose temperature it is to monitor, via the low-voltage DC / DC converter 13. A resistance output 14 of the series resistor 11 is electrically connected to the first comparator input 7. Furthermore, the temperature sensor 10 is electrically connected to the first comparator input 7. Software of the device 2 is configured to provide a predetermined voltage, which corresponds to the threshold temperature, to the second comparator input 8.The triggering device 5 is configured to trigger an interrupt at the comparator output 9 to initiate the determination of the duration when a voltage at the first comparator input 7 exceeds the predetermined voltage at the second comparator input 8 because the temperature of the battery 3 exceeds the threshold temperature. The processor 4 then causes the duration of the period or periods of excess to be determined and permanently stored in the result memory 6. The device 2 has a button cell (not shown) as an emergency battery to power the device 2 if the battery 3 is disconnected or otherwise deactivated. Thus, the device 2 can monitor the battery 3 independently of an operating state of the battery 3.

[0051] In the second embodiment of the device 2, which is shown in Fig. 5, the triggering device 5 is not a software comparator, but a hardware comparator. The electrical circuit of the device 2 thus comprises a separate electrical component to perform a comparison between the predetermined threshold temperature and the measured temperature of the battery 3. The processor 4 is therefore omitted in this embodiment for determining the duration. The result memory 6 is also integrated in the device 2, in contrast to the first embodiment. Otherwise, the structure and function of the first and second embodiments are identical, so that the description of the Fig. 4. The device 2 may again be the CMC or alternatively, for example, an additional electrical circuit of the vehicle 1 attached to the battery 3.

[0052] In the third embodiment from Fig. 6, a temperature switch is provided instead of the comparator as the triggering device 5. The temperature switch is configured to monitor the temperature of the battery 3 and to close the electrical circuit of the device 2 as soon as the temperature exceeds the threshold temperature, and then to cause the device 2 to determine the duration of the excess. The temperature switch thus combines the function of the temperature sensor 10 with the triggering device 5. An additional temperature sensor 10, as present in the first and second embodiments, can thus advantageously be omitted. The result memory 6 here comprises, for example, the processor 4. If the temperature switch, which is the triggering device 5, closes when the threshold temperature is exceeded, this triggers an interrupt that causes the result memory 6 to determine the duration of the period(s) in which the threshold temperature is exceeded.The low-voltage DV / DC converter 13 is connected upstream of the temperature switch to prevent overloading of the electrical components of the device 2, which is powered by the battery 3 via the low-voltage DV / DC converter 13. The result memory 6 is arranged externally to the device 2, for example, in a control unit (not shown) of the vehicle 1.

[0053] In the fourth embodiment from Fig. In Figure 7, a temperature fuse is provided as the triggering device 5 instead of the comparator. The temperature fuse combines the function of the temperature sensor 10 with the triggering device 5. An additional temperature sensor 10, as present in the first and third embodiments, can thus also be omitted here.

[0054] The result memory 6 here comprises, for example, the processor 4 (not shown). If the thermal fuse, which is the triggering device 5, blows when the threshold temperature is exceeded or is triggered, thereby interrupting the electrical circuit, an interrupt is triggered that causes the result memory 6 to determine the duration of the period that has elapsed since the threshold temperature was exceeded. If a workshop subsequently replaces the thermal fuse, it determines, for example, the maximum period for which the threshold temperature can have been exceeded as the period between the triggering of the thermal fuse and the replacement of the thermal fuse. The low-voltage DV / DC converter 13 is connected upstream of the thermal fuse to prevent overloading of the electrical components of the device 2, which in turn is powered by the battery 3 via the low-voltage DV / DC converter 13.The triggering device 5 and the result memory 6 are again separate components. The result memory 6, for example, is a remotely located memory at the manufacturer's site, to which the time at which the thermal fuse is triggered is transmitted via a wireless connection in order to document the time until the thermal fuse is replaced in a way that prevents deletion.

[0055] In the fifth embodiment of the device 2 in Fig.8, the device has a carrier sheet 15 comprising a chemical substance 16 configured to determine the duration of the one or more periods during which the temperature exceeds the threshold temperature. For this purpose, a time scale 17 is arranged on the carrier sheet 15 adjacent to the chemical substance 16. The time scale 17 indicates, for example, a duration between 0 and 5 hours. When the threshold temperature of the battery 3 is exceeded, the chemical substance 16 changes its color in sections along the time scale 17, namely continuously. Such time-temperature indicators are known from other technical fields, such as the temperature measuring strip from DeltaTrak®, Pleasanton, CA, USA, model 51056, so a detailed explanation of their functionality is omitted here.However, these known temperature measuring strips are not suitable for the automotive sector in terms of either the temperature range or the duration of the threshold temperature being exceeded, but must first be adapted accordingly with regard to the chemical substance 16 and the time scale 17. As mentioned in the general part of the description, in embodiments not shown, the time scale 17 can also indicate a duration of days or weeks instead of hours, depending on the battery 3 to be monitored.

[0056] In other words, the core of the invention consists in diagnosing whether a maximum permissible operating temperature of a battery 3 has been exceeded using a temperature threshold sensor, such as the device 2. The diagnostic information is preferably stored in a tamper-proof result memory 6. The aging of the battery 3 is accelerated by elevated temperatures. If the vehicle 1, particularly with a fully charged battery 3, is exposed to an elevated temperature for a certain period of time, the battery 3 ages. This can lead to the usable energy falling below the manufacturer's guaranteed level. This can trigger a warranty claim. Until now, this could not be diagnosed, and tampering might not have been detected.In the course of this invention, exceeding a threshold temperature defined via software, hardware, or a chemical substance 16, for example, triggers the recording of the duration of the threshold temperature exceedance and its tamper-proof storage in a result memory 6. In some embodiments, an ASIC is located on the CMC of the vehicle 1, which, among other things, reads one or more temperature sensors 10, which can be located in particular on the HV battery cells of the battery 3. This allows a simple solution to be implemented in software. Only an intervention in the software is necessary. An additional hardware unit is not required, which is why this embodiment can be particularly advantageous. List of reference symbols 1 vehicle 2 Device 3 Battery 4 processors 5 Release device 6 result storage 7 first comparator input 8 second comparator input 9 Comparator output 10 Temperature sensor 11 Series resistor 12 resistance input 13 low-voltage DC / DC converters 14 Resistance output 15 carrier sheets 16 chemical substance 17 Timescale S21 - S23 Process steps S31 - S34 Process steps QUOTES CONTAINED IN THE DESCRIPTION

[0000] This list of documents submitted by the applicant was generated automatically and is included solely for the convenience of the reader. This list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions. Cited patent literature

[0000] US 2022 / 0161682 A1

[0006]

Claims

[1] Method for diagnosing a battery (3) of a vehicle (1), comprising the steps: - monitoring (S21, S31) a temperature of the battery (3); and - determining (S22, S32) whether the temperature exceeds a predefined threshold temperature; characterized by - determining (S23, S33) a duration of one or more periods during which the temperature exceeds the threshold temperature in response to determining that the temperature exceeds the predefined threshold temperature. [2] Method according to claim 1, characterized by - determining the duration using a first time at which the temperature crosses the threshold temperature upwards and a second time at which the temperature crosses the threshold temperature downwards, wherein the second time follows the first time and the first time defines a lower limit of a period and the second time defines an upper limit of the period. [3] Method according to claim 1 or 2, characterized by - permanent storage (S34) of the specified duration. [4] Method according to one of the preceding claims, characterized by that the temperature monitoring is carried out independently of the operating state of the battery (3). [5] Device (2) which is arranged to carry out the method according to one of claims 1 to 4. [6] Device (2) according to claim 5, characterized bythat the device (2) is a data processing device comprising a processor (4) configured to carry out the method according to one of claims 1 to 4. [7] Device (2) according to claim 5 or 6, characterized by a triggering device (5) arranged to cause the device (2) to determine the duration when the temperature exceeds the threshold temperature. [8] Device (2) according to claim 5, characterized by a carrier sheet (15) comprising a chemical substance (16) configured to determine the duration of the one or more periods during which the temperature exceeds the threshold temperature. [9] A computer program product comprising instructions which, when the program is executed by a processor (4), cause the processor (4) to carry out the method according to any one of claims 1 to 4. [10] Vehicle (1) comprising a device (2) according to any one of claims 5 to 8.

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