Method, device, computer program product and computer-readable storage medium for preventing leakage currents in an HV battery system

Abstract

The present invention relates to a method, a device, a computer program, and a computer-readable storage medium for preventing the formation of leakage currents in a high-voltage battery system of a vehicle. The method according to the invention is, in particular, a computer-executed method and comprises several steps. In a first step, the vehicle's height (h) is determined. In a further step, this (operating) height (h) is compared with a stored threshold value of a maximum permissible height (h). max If the height (h) exceeds the maximum permissible height (h max ), a limitation of the maximum permissible State of Charge (SoC) occurs. max )·

Description

[0001] The present invention relates to a method, a device, a computer program product and a computer-readable storage medium for preventing the formation of leakage currents in a vehicle's HV battery system.

[0002] The term HV battery system (high-voltage battery system) refers specifically to the system for supplying power to a vehicle's traction electric motors. The core component of the HV system, or HV battery system, is the vehicle's traction battery, or HV battery.

[0003] Such a high-voltage battery system comprises various components. For example, it incorporates different measuring systems for battery management. These systems feature conductor strings arranged side by side. The spacing between the conductors is chosen to prevent any leakage current, or at most a negligible current, from forming between them. However, the formation of leakage currents depends primarily on the insulating properties, or rather the insulating strength, of the air surrounding the conductors. As the operating altitude increases above sea level, the air density decreases, and consequently, due to the reduced number of molecules in the air, the insulating strength also decreases. Therefore, the probability of unwanted leakage currents occurring increases with altitude. As a result, the conductor spacing is designed for a specific maximum operating altitude.

[0004] This means, firstly, that charging stations located above the maximum operating height are excluded from use or their use is made more complicated, or that vehicles that are always far below the maximum operating height are over-dimensioned with regard to creepage current formation.

[0005] The following systems are known from the prior art. Document US 2022 0 266 716 A1 describes a device for controlling the state of charge (SOC) of a hybrid vehicle battery, whereby an SOC is set during a charging process depending on a reference distance.

[0006] DE 10 2016 201 986 A1 describes a method and implements a control of the supply voltage to perform the following steps: specifying a model that describes a relationship between a maximum supply voltage and an operating altitude of the vehicle relative to sea level; determining the current operating altitude of the vehicle relative to sea level; setting a target supply voltage based on the specified model, taking into account the determined current operating altitude, and adjusting the supply voltage so that the supply voltage does not exceed the target supply voltage.

[0007] DE 10 2022 123 192 A1 describes a battery system with altitude-dependent interconnection of battery units. DE 10 2021 106 190 B3 describes a device and method for the production and prevention of the degradation of electrical components in a vehicle. US 2024 0 123 794 A1 describes a control device for a vehicle comprising a motor, a rotating electric machine driven by the motor and generating electrical energy, and an air conditioning system, wherein, in a case where ensuring propulsion takes precedence over generating electrical energy, the power output of the rotating electric machine is regulated according to altitude.

[0008] DE 10 2019 205 924 A1 describes a method for operating a motor vehicle, wherein at least one position value of a current geographical position of the motor vehicle is determined, and depending on the determined position value, at least one first function of the motor vehicle is triggered, characterized in that the at least one position value represents a current geographical height of the motor vehicle, wherein the current height is repeatedly determined and the at least one first function is triggered as soon as the current height reaches or exceeds a predetermined first limit.

[0009] In light of the prior art presented above, the object of the present invention is to provide a method, a device, a computer program product and a computer-readable storage medium for preventing the formation of leakage currents in a vehicle's high-voltage battery system.

[0010] This problem is solved by the subject matter of the independent claims. Advantageous embodiments of the invention are disclosed in the dependent claims.

[0011] The method according to the invention is, in particular, a computer-executed method and comprises several steps. In a first step, the vehicle's altitude is determined. This determined altitude corresponds to the vehicle's current operating altitude above sea level. This is achieved, in particular, using a satellite-based positioning system, where the corresponding altitude data is stored along with the position data, thus enabling the determination of the current operating altitude. An example of a satellite-based positioning system is the GPS system, which is used, in particular, for vehicle navigation. Alternatively or additionally, the vehicle's current operating altitude can also be determined using barometric sensors.

[0012] In a further step of the process, the currently determined (operating) height is compared with a stored threshold value for a maximum permissible height. The maximum permissible height thus corresponds to the maximum permissible operating height for which the vehicle is designed. More precisely, it corresponds to the height for which the air and creepage distances of the high-voltage battery system are designed, ensuring that no or only negligible leakage currents develop between the conductors of the high-voltage battery system. Due to the lower density of air, its insulating properties and insulating strength deteriorate, so the probability of unwanted leakage currents occurring increases with increasing height. Consequently, the conductor spacing is designed for a specific maximum operating height.The maximum permissible height can vary from vehicle to vehicle, but cannot be adjusted in a vehicle, especially during operation, without hardware changes.

[0013] If the measured current height exceeds the maximum permissible height, the maximum permissible state of charge is limited. The state of charge of a battery is a measure of its current charge level and indicates how much energy is currently stored in the battery relative to its total capacity. It can be determined in the vehicle in various ways, as is known from current technology. The maximum permissible state of charge thus defines the maximum energy level to which the battery may be charged. The state of charge can influence the voltage of the high-voltage battery system. The maximum operating voltage is limited by the state of charge. At higher state of charge levels, the susceptibility to the formation of unwanted leakage currents increases.

[0014] By limiting the maximum permissible state of charge based on altitude, the risk of leakage current formation can be reduced, even at high altitudes above the vehicle's actual operating range. This allows the vehicle to be charged without problems even in regions above the maximum permissible operating altitude, which corresponds to the vehicle's designed operating altitude.

[0015] In an advantageous embodiment of the invention, the maximum permissible state of charge is determined as a function of the difference between the vehicle's current operating height and the maximum permissible height. In other words, if the maximum permissible height is significantly exceeded, the maximum permissible state of charge is limited differently than if the maximum permissible operating height is only slightly exceeded. This allows the maximum permissible state of charge to be variably and optimally adjusted to the current height.

[0016] In particular, the limitation of the maximum permissible state of charge is achieved using a map that outputs a value for the maximum permissible state of charge depending on the vehicle's current measured height. A map provides a simple way to represent the relationship between the current measured height and the maximum permissible state of charge. Alternatively, a lookup table could be used to allow for the specification of values ​​regarding the relationship between the current height and the maximum permissible state of charge, at least in discrete steps.

[0017] In a further advantageous embodiment of the invention, if the currently determined operating height of the vehicle exceeds the maximum permissible height for which it is designed, the battery voltage of the high-voltage battery system is limited. This limitation is specifically dependent on the selected limitation of the maximum permissible state of charge. Limiting the operating voltage of the high-voltage battery system ensures compliance with the required clearances and creepage distances between the cables, in addition to limiting the maximum permissible state of charge. The relationship between the state of charge and the operating voltage is particularly taken into account. Thus, in addition to limiting the maximum permissible state of charge, a further parameter is provided to prevent the formation of leakage currents.

[0018] The device for data processing according to the invention comprises means for carrying out the steps of the method according to the invention.

[0019] The computer program product according to the invention comprises instructions which, when the program is executed by a computer, cause it to execute the method according to the invention.

[0020] The computer-readable storage medium according to the invention comprises instructions which, when the program is executed by a computer, cause it to execute the method according to the invention.

[0021] An embodiment of the invention is described below with reference to the attached [document / reference]. Fig. 1 explained in more detail. Fig. Figure 1 shows a flowchart of an embodiment of the method according to the invention.

[0022] First, the vehicle's current altitude h, also known as its current operating altitude, is determined. This is done, for example, using barometric sensors or, in particular, a satellite-based positioning system such as GPS. Since such a system is already present in most vehicles for navigation, no additional hardware is required to implement the procedure.

[0023] The current height h is compared to a maximum permissible height h. max , also called maximum permissible operating height, compared. The maximum permissible height h max is specified for a vehicle and is based on an air and creepage gap design that prevents the formation of creepage currents.

[0024] In the event that the current height h is the maximum permissible height h max If the vehicle does not exceed the specified limit, it can be used without modification and, in particular, charged at a charging point.

[0025] If the current height h exceeds the maximum permissible height h max However, there is a limit to the maximum permissible State of Charge SoC. max for a charging process at a charging point. This allows the voltage level of the high-voltage battery system, and therefore also the maximum voltage in the conductors, to be limited. This prevents the risk of leakage currents between the conductors, even with the lower insulating strength of the air at high altitudes.

[0026] The limitation is achieved in particular by a SoC characteristic map red , which relates a determined height h to the maximum permissible State of Charge (SoC) max sets the maximum permissible State of Charge SoC. max For example, it might only be 80% of the unlimited state of charge. In this way, the maximum permissible state of charge of the SoC can be determined. maxdepending on the difference between the determined height h and the maximum permissible height h max to be determined.

[0027] The method according to the invention thus also enables design for operating altitudes far below the maximum operating altitude used for vehicle design according to the prior art. When the lower permissible operating altitude is reached, the maximum permissible state of charge is reduced according to the method according to the invention. This allows the creepage distances between two conductors to be designed smaller, and thus the hardware of the HV battery system takes up less space and is lighter. Since most vehicles are primarily used in areas of comparatively low operating altitudes, the method according to the invention ensures safe use of the vehicle even in the exceptional case where the vehicle operates in areas of high operating altitudes. 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 2022 0 266 716 A1

[0005] DE 10 2016 201 986 A1

[0006] DE 10 2022 123 192 A1

[0007] DE 10 2021 106 190 B3

[0007] US 2024 0 123 794 A1

[0007] DE 10 2019 205 924 A1

[0008]

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