Method and Control Device for Temperature Control of a Traction Battery of an Electrically Powered Motor Vehicle

Abstract

A method for temperature control of a traction battery includes predefining a target temperature which the traction battery should have at the end of a journey and upon arrival at a fast-charging station; predicting a temperature which the traction battery will have at the end of the journey and upon arrival at the fast-charging station; determining a temperature difference between the target temperature and the predicted temperature; predefining a temperature control specification for temperature control of the traction battery during the journey of the motor vehicle to the fast-charging station in accordance with the determined temperature difference, so that the target temperature prevails upon arrival at the fast-charging station; and controlling the temperature of the traction battery according to the predetermined temperature control specification during the journey of the vehicle.

Claims

1.-10. (canceled)

11. A method for temperature control of a traction battery of an electrically-powered motor vehicle, the method comprising: predefining a target temperature which the traction battery is intended to assume at an end of a journey, upon arrival at a rapid charging station; predicting a predicted temperature which the traction battery will assume at the end of the journey, upon arrival at the rapid charging station, without the temperature control; determining a temperature difference between the target temperature and the predicted temperature of the traction battery; defining a temperature control instruction for the temperature control of the traction battery during the journey of the motor vehicle to the rapid charging station, in accordance with the temperature difference, such that the target temperature is achieved upon arrival at the rapid charging station; and controlling a temperature of the traction battery in accordance with the temperature control instruction during the journey of the motor vehicle to the rapid charging station.

12. The method according to claim 11, wherein the traction battery is temperature-controlled, in accordance with the temperature control instruction, from a start of travel to the rapid charging station.

13. The method according to claim 11, wherein: heat-up of the traction battery is suspended or delayed if it is determined, by reference to at least one criterion, that any heat-up of the traction battery is not necessary.

14. The method according to claim 11, further comprising: estimating a power loss of the traction battery which will occur during the travel of the motor vehicle to the rapid charging station, wherein the predicted temperature of the traction battery is predicted in consideration of the power loss.

15. The method according to claim 11, further comprising: delivering route data for the journey of the motor vehicle to the rapid charging station, wherein the predicted temperature of the traction battery is predicted in consideration of the route data.

16. The method according to claim 11, further comprising: delivering driver data which characterize driving behavior of a driver of the motor vehicle, wherein the predicted temperature of the traction battery is predicted in consideration of the driver data.

17. The method according to claim 11, further comprising: determining an initial temperature of the traction battery prior to the start of travel to the rapid charging station, wherein the predicted temperature of the traction battery is predicted in consideration of the initial temperature.

18. The method according to claim 11, further comprising: estimating a duration of travel to the rapid charging station, wherein the predicted temperature of the traction battery is predicted in consideration of the duration of travel.

19. A control device for temperature control of the traction battery of the electrically-powered motor vehicle, wherein the control device is configured to execute the method according to claim 11.

20. An electrically-powered motor vehicle comprising the control device according to claim 9.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0021] FIG. 1 shows a highly schematic representation of an electrically-powered motor vehicle.

[0022] FIG. 2 shows a diagram in which different temperature characteristics of a traction battery of the motor vehicle, pending arrival at a rapid charging station, are represented.

DETAILED DESCRIPTION OF THE DRAWINGS

[0023] In the figures, identical and functionally equivalent elements are represented by the same reference symbols.

[0024] An electrically-powered motor vehicle 1 is shown in a highly schematic representation in FIG. 1. The motor vehicle 1 comprises inter alia a traction battery 2, an electric drive machine 3 and a control device 4. In a manner which is known per se, the traction battery 2 is employed, inter alia, for the supply of energy to the electric drive machine 3 which, in turn, propels the motor vehicle 1. The control device 4 is designed to execute a temperature control of the traction battery 2, which is described in greater detail hereinafter, during the travel of the motor vehicle 1.

[0025] Particularly during long journeys, it can occur that the traction battery 2 requires recharging. Customarily, it is thus desirable that the traction battery 2 can be charged in a particularly rapid manner, in order to permit a particularly prompt resumption by a driver of their journey in the motor vehicle 1. The potential power take-up of the traction battery 2 during a rapid charging process is strongly influenced, inter alia, by the temperature of the traction battery 2. Customarily, the traction battery 2 should lie within a temperature range between 15 degrees Celsius and 35 degrees Celsius, such that the traction battery 2 can be charged without damage, and in a particularly rapid manner. However, particularly at low ambient temperatures, it can occur that the traction battery 2 lies below this temperature window.

[0026] A method for the temperature control of the traction battery 2 is described in greater detail hereinafter, with reference to FIG. 2. In the diagram, various temperature characteristics 6, 7, 8 of the traction battery 2 along a route s, pending arrival at a rapid charging station 5, are plotted schematically. Before the driver departs in the motor vehicle 1, a target temperature T.sub.1 can be predefined, which the traction battery 2 is intended to achieve, after travel, upon arrival at the rapid charging station 5. The target temperature T.sub.1 is selected such that the traction battery 2 can be charged without damage, and in a particularly rapid manner, by way of the rapid charging station 5. Additionally, a temperature T.sub.2 is predicted, which the traction battery 2 will or would assume after travel, in the absence of temperature control, upon arrival at the rapid charging station 5. The temperature characteristic 6 characterizes the temperature movement of the traction battery 2 along the route s pending arrival at the rapid charging station 5, in the event that the traction battery 2 is not additionally subject to temperature control or heat-up. In the knowledge of the target temperature T.sub.1 and the temperature T.sub.2, which would be achieved in the absence of additional temperature control, a temperature difference T.sub.3 is determined, i.e. the difference between the target temperature T.sub.1 and the temperature T.sub.2.

[0027] In the knowledge of the temperature difference T.sub.3, a temperature control instruction for the temperature control of the traction battery 2 during the journey to the rapid charging station 5 is defined, such that the target temperature T.sub.1 will be achieved upon arrival at the rapid charging station 5. Following the start of travel to the rapid charging station 5, the traction battery 2 is correspondingly temperature-controlled in accordance with the defined temperature control instruction, such that the target temperature T.sub.1 is achieved upon arrival at the rapid charging station 5. The above-mentioned process steps can be executed by the control device 4. The control device 4 is thus designed and configured for the execution of the above-mentioned process steps.

[0028] According to the diagram represented in FIG. 2, the traction battery 2 is temperature-controlled in accordance with the temperature control instruction with immediate effect from the start of travel to the rapid charging station 5. This can be seen from the temperature characteristic 7, which shows a substantially steeper gradient than the temperature characteristic 6. Depending upon the length of the route s, and other marginal conditions, it can thus be provided that the traction battery 2 undergoes heat-up immediately after departure. The traction battery 2 can thus be heated to an ideally optimum service temperature immediately after departure, in a particularly rapid manner. The traction battery 2 can thus be operated within a particularly effective efficiency range, and delivers an effective power output, with no resulting damage to the traction battery 2.

[0029] The temperature characteristic 8 then characterizes that part of the travelled route s to the rapid charging station 5 in which the traction battery 2 is no longer subject to additional temperature control or heat-up. In the present case, the temperature characteristics 6, 8 are plotted with equal gradients, although this is not necessarily the case.

[0030] For the temperature control or heat-up of the traction battery 2, it can be provided, for example, that the electric drive machine 3 is operated in an efficiency range which is inferior to a construction-related maximum potential efficiency of the electric drive machine 3. By way of the “trimming” of the electric drive machine 3, for example directly after the start of travel, it is possible to generate surplus heat which, in turn, can be employed for the heat-up of the traction battery 2. Alternatively or additionally, for example, it is also possible to employ a coolant circuit for the temperature control of the traction battery 2. Other options for the heat-up of the traction battery 2 are also additionally or alternatively possible.

[0031] In order to estimate the temperature characteristic 6, and thus the temperature Ta, it is possible, for example, to estimate a power loss of the traction battery 2 which will occur during the journey of the motor vehicle 1 to the rapid charging station 5. In consideration of this estimated power loss, it is possible to determine, in a relatively accurate manner, the temperature T.sub.2 which will be assumed by the traction battery 2, in the absence of temperature control, upon arrival at the rapid charging station 5. Consideration can also be given to power losses on other components of the motor vehicle 1 which, for example by way of thermal transfer, can heat up the traction battery 2. In particular, it is also possible to constitute a form of overall energy balance, which can be based upon measurements and/or simulations, in order to estimate or determine how the temperature characteristic 6 will progress, and ultimately also to then determine the temperature T.sub.2 which will be assumed by the traction battery 2 upon arrival at the rapid charging station 5, if the traction battery 2 does not undergo any additional heat-up.

[0032] Route data for the route s can also be delivered to the control device 4, for example data on a gradient profile, weather data, speed limits or similar. In the knowledge of the route data, it is possible for the temperature T.sub.2 of the traction battery 2 to be determined in a particularly accurate manner.

[0033] Moreover, it is also possible to deliver characteristic data for the driving behavior of the driver of the motor vehicle 1. Thus, for example, a driver profile can be progressively constituted and managed, which describes or characterizes how the relevant driver drives the motor vehicle 1. In the knowledge of the customary driving behavior of the driver, it is possible to estimate or determine the temperature characteristic 6 in a particularly accurate manner, such that the temperature T.sub.2 can likewise be predicted in a particularly accurate manner.

[0034] Moreover, an initial temperature of the traction battery 2 can also be considered, which is present before the start of travel, or upon the start of travel to the rapid charging station 5. In consideration of the initial temperature of the traction battery 2, it is likewise possible to determine the temperature characteristic 6 and thus, additionally, the temperature T.sub.2.

[0035] Moreover, it is also possible for a duration of travel to the rapid charging station 5 to be estimated. In the knowledge of the duration of travel, and further parameters such as, for example, the external temperature or similar, it is possible for the temperature characteristic 6 of the traction battery 2, and thus the temperature T.sub.2, to be determined in a particularly accurate manner.

[0036] By way of the method thus described for the temperature control of the traction battery 2 en route to the rapid charging station 5, it is possible for the traction battery 2 to undergo prompt heat-up, such that it achieves its target temperature T.sub.1. It can thus be ensured, upon arrival at the rapid charging station 5, that the traction battery 2 can be charged in a particularly rapid manner, with no resulting damage.

LIST OF REFERENCE SYMBOLS

[0037] 1 Electrically-powered motor vehicle [0038] 2 Traction battery [0039] 3 Electric drive machine [0040] 4 Control device [0041] 5 Rapid charging station [0042] 6 Temperature characteristic [0043] 7 Temperature characteristic [0044] 8 Temperature characteristic [0045] s Route [0046] T.sub.1 Target temperature [0047] T.sub.2 Temperature assumed by the traction battery upon arrival at the rapid charging station, in the absence of temperature control [0048] T.sub.3 Temperature difference between the target temperature and the temperature assumed by the traction battery upon arrival at the rapid charging station 5, in the absence of temperature control