Method for automatically preconditioning a traction battery of a battery electric vehicle for a charging process

Abstract

Method for automatically preconditioning a traction battery of a battery electric vehicle for a charging process, characterized by the following features: - Capturing a display event where the current fast-charging capability of the traction battery is shown via a display unit of the vehicle, - Logging the frequency of calls to the display of the current fast loading capability within a specified time window, - Determining a display duration during which the current fast charging capability is shown, - Determining an interest value from at least the frequency of calls and the display duration, - Comparing the level of interest with a threshold value, and - if the threshold is exceeded, automatic activation of a thermal management system of the traction battery to heat or cool the traction battery to a temperature range intended for charging.

Description

[0001] The present invention relates to a method for automatically preconditioning a traction battery of a battery-electric vehicle for a charging process. The invention further relates to a device, in particular an electronic control unit of the vehicle, a computer program, and a machine-readable storage medium. State of the art

[0002] Battery electric vehicles have a traction battery whose power consumption during charging and power output during driving depend on the battery temperature. For high charging power and battery-friendly operation, it is advantageous to operate the traction battery within a temperature range suitable for charging, which can be considered its "optimal temperature." To achieve this temperature range, a preconditioning process is known from the prior art, in which the traction battery is selectively heated or cooled by means of a thermal management system.

[0003] In the current state of the art, the driver is shown the current fast-charging capability in one or more menus, particularly in the instrument cluster or a central display, for example, as the maximum available fast-charging power in kilowatts. Mechanisms for triggering preconditioning are also known. On the one hand, the driver can start preconditioning manually, for example, via a virtual button on a user interface. On the other hand, the driver can plan a charging session via the vehicle's navigation system, whereby the vehicle controls the preconditioning based on the planned charging stop so that the traction battery is in the optimal temperature range for charging when a charging station is reached.

[0004] The disadvantage is that these known triggers are often not used in practice. Not all drivers are aware of the option to manually activate preconditioning. Furthermore, not all drivers use the vehicle's built-in navigation system; some rely on external navigation apps or don't use navigation at all. In such cases, preconditioning often fails to activate despite an imminent need for charging, even though the current fast-charging capability indicator already signals to the driver that the charging power may be limited depending on the temperature. Disclosure of the invention

[0005] One problem is reliably initiating preconditioning of the traction battery for a charging process, even when the driver neither schedules a charge in the vehicle navigation system nor manually activates preconditioning. Another problem is utilizing a technical indicator of an impending charging intention that is already present in the vehicle and available without additional input from the driver.

[0006] The problem described is solved according to claim 1. The vehicle monitors the use of a display indicating the current fast-charging capability and derives an interest value from the usage pattern, which serves as a technical criterion for the automatic activation of preconditioning. For this purpose, display events in which the current fast-charging capability is shown are recorded, and at least the call frequency within a predefined time window and the display duration are determined. An interest value is calculated from these parameters and compared with a threshold value. If the interest value exceeds the threshold value, the thermal management system of the traction battery is automatically controlled to bring the traction battery into a temperature range suitable for charging by heating or cooling.In an advantageous embodiment, gaze direction detection can additionally be used to record the driver's gaze duration and frequency at the display and to include this information in the determination of the interest value.

[0007] This approach offers the advantage that preconditioning can be triggered without charging planning or separate manual activation by using existing vehicle information as an indicator of charging intent. This allows the traction battery to be brought into a favorable temperature range more frequently and in a timely manner, resulting in shorter charging times and a gentler charging mode. At the same time, operation is simplified, as the automatic triggering is linked to an observable interaction pattern and requires no additional input steps.

[0008] Further advantageous embodiments of the invention are specified in the dependent patent claims. Brief description of the drawings Fig. Figure 1 schematically shows an embodiment of the invention. Embodiments of the invention

[0009] One possible embodiment of the invention will now be explained in detail with reference to the drawing. Fig.Figure 1 illustrates a vehicle cockpit with an instrument cluster displaying various vehicle information to the driver. The instrument cluster includes a display showing the current fast-charging capability of the traction battery, for example, as the maximum available fast-charging power in kilowatts. This display can appear in a dedicated menu, as a tile, or as an overlay within a battery overview. The current fast-charging capability can be derived from a battery management system that determines the maximum permissible charging power, taking into account cell temperature, state of charge, component power limits, and other operating parameters.

[0010] The vehicle features an electronic control unit that communicates with the display unit and the battery management system. The control unit is configured to detect display events that indicate the current fast-charging capability. A display event can be defined as the driver accessing a battery status menu, switching views, or selecting an information page that shows the current fast-charging capability. This detection can occur via signals from the human-machine interface's operating logic, such as status information from the currently active display view.

[0011] To determine the call frequency, the control unit logs how often the display of the current fast-charging capability is made visible within a predefined time window. This time window can be chosen to capture a temporal density of calls that suggests the driver is currently engaged with the topic of charging. Additionally, the control unit determines a display duration by measuring the time interval between the start and end of visibility of the current fast-charging capability display for each display event. The display duration can be calculated from timestamps of the activation and deactivation of the relevant view or from a continuously recorded visibility status.

[0012] The control unit determines an interest score based on the call frequency and display duration. A weighting system can be implemented, where a high call frequency and a long display duration increase the interest score. In one configuration, the interest score can be considered sufficient only if the call frequency reaches a minimum number within the time window and, at the same time, the cumulative or average display duration exceeds a minimum value. This reduces the risk of unintentional triggering due to random or short calls.

[0013] In a further embodiment, the vehicle is equipped with gaze direction detection that records the driver's gaze direction relative to the display unit. This gaze direction detection can include an interior camera and an evaluation unit that determines gaze vectors or target areas. While the current fast-charging capability is displayed, the control unit determines the duration and frequency of the driver's gaze on the display. These parameters are incorporated into the interest score by, for example, only considering glances that fall within a defined viewing zone of the display unit and have a minimum duration. This more precisely aligns the interest score with the actual perception of the display.

[0014] The control unit compares the determined interest value with a threshold value. This threshold value can be parameterized for specific vehicles and can vary depending on operating conditions. If the threshold value is exceeded, the control unit activates a thermal management system for the traction battery to initiate preconditioning. The thermal management system can include a coolant circuit, an electric heater, a heat pump, or a chiller connection and is designed to adjust the battery temperature towards a temperature range intended for fast charging. The control can be implemented as a closed-loop system, in which the battery temperature is measured via temperature sensors and compared with a target temperature specified by the battery management system for high charging power.

[0015] Preconditioning can be terminated when the target temperature is reached, when a maximum preconditioning time has been exceeded, or when the interest value falls below a threshold indicating a decreasing charging interest. Additionally, preconditioning can be prevented or limited if the traction battery is already within the target temperature range or if operating limits prevent a temperature change. In a further configuration, the driver can receive feedback on the start of preconditioning via the display unit. This feedback serves as status information, making the automatic control of the thermal management system transparent.

[0016] The described monitoring of the display interaction with the current fast charging capability enables automatic preconditioning, which does not require charging planning by the vehicle navigation system or manual activation, yet is based on a technically measurable, user-related interest indicator.

Claims

[1] Method for automatically preconditioning a traction battery of a battery electric vehicle for a charging process, characterized by the following characteristics: - Capturing a display event where the current fast-charging capability of the traction battery is shown via a display unit of the vehicle, - Logging the frequency of calls to the display of the current fast loading capability within a specified time window, - Determining a display duration during which the current fast charging capability is shown, - Determining an interest value from at least the frequency of calls and the display duration, - Comparing the level of interest with a threshold and - if the threshold is exceeded, automatic activation of a thermal management system of the traction battery to heat or cool the traction battery to a temperature range intended for charging. [2] Method according to claim 1, characterized by the following characteristics: - Detecting a driver's gaze direction using gaze direction recognition, - Determining the duration and frequency of the driver's gaze at the display unit while the current fast charging capability is being shown, and - Including the viewing duration and viewing frequency in the interest score, whereby exceeding the threshold is only determined if, in addition to the call frequency and the display duration, a predetermined viewing duration or a predetermined viewing frequency is reached. [3] Device, characterized by the following characteristic: - the device is configured to carry out a method according to one of claims 1 or 2. [4] Computer program which is configured to perform all steps of a method according to claim 1 or 2. [5] Machine-readable storage medium with a computer program stored thereon according to claim 4.

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