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Title:
METHOD OF OPERATING A BATTERY IN AN ELECTRICALLY POWERED VEHICLE
Document Type and Number:
WIPO Patent Application WO/2016/083529
Kind Code:
A1
Abstract:
The present invention provides a method of operating a battery in an electrically powered vehicle, the method comprising the steps of: a) Detecting location information of the vehicle; b) Detecting driving information of the vehicle; c) Assessing a temperature adjustment requiring condition of the battery, wherein the temperature adjustment requiring condition of the battery starts at a time t1, wherein t1 lies in the future, and wherein the temperature adjustment requiring condition of the battery is assessed based on the location information and the driving information; and d) Starting pre-adjusting the temperature of the battery at a time t0 based on the assessed temperature adjustment requiring condition of the battery, wherein t0 is prior to t1. Such a method provides improved safety, long-life stability as well as efficiency of the battery.

Inventors:
PATEY TIMOTHY (CH)
KERLER WOLFGANG (CH)
MARIAPPAN SENTHIL NATHAN (CH)
Application Number:
PCT/EP2015/077819
Publication Date:
June 02, 2016
Filing Date:
November 26, 2015
Export Citation:
Click for automatic bibliography generation   Help
Assignee:
ABB TECHNOLOGY AG (CH)
International Classes:
B60L11/18
Domestic Patent References:
WO2013158083A12013-10-24
Foreign References:
DE102013002198A12014-08-07
DE102008017699A12008-11-06
EP1876051A12008-01-09
DE102012204410A12013-09-26
DE102011089962A12013-06-27
US20140012447A12014-01-09
US20120297809A12012-11-29
US20130269911A12013-10-17
US8620506B22013-12-31
Other References:
ANONYMOUS: "Battery State of Health Determination", 14 July 2011 (2011-07-14), XP055189901, Retrieved from the Internet [retrieved on 20150519]
MERCEDESBENZ: "eMercedesBenz - The Unofficial Mercedes-Benz Weblog", 11 October 2005 (2005-10-11), XP055189875, Retrieved from the Internet [retrieved on 20150518]
Attorney, Agent or Firm:
ABB PATENT ATTORNEYS (Intellectual Property CH-IPBrown Boveri Strasse 6, 5400 Baden, CH)
Download PDF:
Claims:
Claims

1. Method of operating a battery in an electrically powered vehicle, the method comprising the steps of:

a) Detecting location information of the vehicle, which location information give information about the power requirements of the battery at prospective locations;

b) Detecting driving information of the vehicle, which driving information give information as to when the vehicle will reach the prospective locations; c) Assessing a temperature adjustment requiring condition of the battery, wherein the temperature adjustment requiring condition of the battery starts at a time ti, wherein ti lies in the future, and wherein the temperature adjustment requiring condition of the battery is assessed based on the location information and the driving information; and

d) Starting pre-adjusting the temperature of the battery at a time to based on the assessed temperature adjustment requiring condition of the battery, wherein to is prior to ti.

2. Method according to claim 1 , characterized in that step d) comprises pre- cooling the battery.

3. Method according to claim 1 or 2, characterized in that the temperature

adjustment requiring condition of the battery comprises a discharging step of the battery.

4. Method according to any of the preceding claims, characterized in that step a) is performed by means of a satellite navigation system.

5. Method according to any of the preceding claims, characterized in step b) is performed by means of a navigation system.

6. Method according to any of the preceding claims, characterized in that the location information comprise at least one of the following information: the present location, geographic information, level crossings information, traffic lights information, and/or curves information.

7. Method according to any of the preceding claims, characterized in that the driving information comprise at least one of the following information: route information, time information, timetable information, speed information, and/or driving behaviour of the driver.

8. Method according to claim 7, characterized in that step b) is performed based on a predefined route.

9. Method according to any of the preceding claims, characterized in that the temperature of the battery is measured by a temperature sensor and that the temperature of the battery is used for assessing the temperature adjustment requiring condition of the battery.

10. Method according to any of the preceding claims, characterized in that the ambient temperature is measured and that the ambient temperature is used for assessing the temperature adjustment requiring condition of the battery.

1 1. Method according to any of the preceding claims, characterized in that to is in the range of equal or less than 600s prior to ti.

12. Method according to any of the preceding claims, wherein step d) is adapted to the state of health of the battery.

13. System for operating a battery in an electrically powered vehicle, characterized in that the system comprises a control unit being configured for performing a method as described in any of claims 1 to 12.

14. System according to claim 13, characterized in that the system is self-learning.

15. System according to any of claim 13 or 14, characterized in that the system is positioned in a vehicle of public transport.

Description:
Description

METHOD OF OPERATING A BATTERY IN AN ELECTRICALLY POWERED

VEHICLE

Technical Field

[0001] The present invention relates to a method of operating a battery in an electrically powered vehicle. The present invention particularly relates to a method of adjusting the temperature of a battery in an electrically powered vehicle. The present invention further relates to a battery system, configured for performing such a method, wherein the battery system is part of an electrically powered vehicle.

Background Art

[0002] Battery based energy storing devices are well known in the art and are used, for example, in electrically driven vehicles. Thermal management is thereby an important factor for driving the batteries in appropriate conditions and for securing long-life stability thereof.

[0003] Known from US 2014/0012447 A1 is a process for charging a battery pack of a vehicle. The vehicle has a cooling system that automatically turns on to cool the battery pack when its temperature reaches a high threshold temperature. Further, a controller is used which may include a thermal model of a heating performance of the battery pack while under charge, the operating heating rise of the battery pack in the event the vehicle is driven at the predetermined operating condition, and a cooling

performance of the cooling system in cooling the battery when the vehicle is parked.

[0004] Document US 2012/0297809 A1 describes a thermal management system for an electric vehicle. According to this document, a battery circuit temperature sensor is provided for sensing the temperature of the fluid in the battery circuit. A controller determines that the temperature at the temperature sensor exceeds a selected threshold temperature and the controller may act to hold the temperature beneath a threshold

temperature.

[0005] Document US 2013/026991 1 A1 describes vehicles that include both an electric traction motor and a range extending device such as an internal combustion engine. Such vehicles comprise thermal management system with a battery circuit, the battery circuit being configured for controlling the temperature of battery packs based on the temperature provided by a battery circuit temperature sensor.

[0006] Document WO 2013/158083 describes a vehicle having a drive train

having an electrical motor and an internal combustion engine available for propulsion. A control system dynamically establishes rules for operating the drive train. The rules provide for handling requests for propulsion, obtaining data relating to expected conditions of operation including one or more of weather, traffic and road conditions. Responsive to requests for propulsion and the obtained data using telematics it is determined what proportion of a request for propulsion to meet from the internal combustion engine and what proportion to meet from the electrical motor.

[0007] Document US 8,620,506 B2 describes a method for thermal management of an electric vehicle. The method detects if a traction battery is connected to a charger and power source. The temperature of the battery is regulated to be within an operating temperature range when the vehicle is operating. The temperature of the battery is regulated to be within a charging temperature range when the battery is connected to the charger and power source and the ambient temperature is outside an environmental temperature range. The battery is preconditioned to a battery drive temperature when the ambient temperature is outside the environmental temperature range and the battery is connected to the charger and power source.

[0008] There is, however, still potential for improving the thermal management of batteries, especially in electrically driven vehicles. Disclosure of Invention

[0009] It is an object of the present invention to provide a method of operating a battery in an electrically powered vehicle which may overcome at least one disadvantage of the prior art. It is particularly an object of the present invention to provide a method of operating a battery in an electrically powered vehicle which may provide an improved temperature adjustment of a battery in an electrically driven vehicle.

[0010] This object is achieved by the features according to the independent

claims. Advantageous embodiments are given in the dependent claims, the description as well as in the figures, wherein additional features described in the dependent claims, in the figures as well as in the description may form part of the invention, either alone or in any

combination, unless not explicitly described otherwise.

[001 1] In particular, the present invention provides a method of operating a

battery in an electrically powered vehicle, the method comprising the steps of:

[0012] a) Detecting location information of the vehicle, which location

information give information about the power requirements of the battery at prospective locations;

[0013] b) Detecting driving information of the vehicle, which driving information give information as to when the vehicle will reach the prospective locations;

[0014] c) Assessing a temperature adjustment requiring condition of the

battery, wherein the temperature adjustment requiring condition of the battery starts at a time ti, wherein ti lies in the future, and wherein the temperature adjustment requiring condition of the battery is assessed based on the location information and the driving information; and

[0015] d) Starting pre-adjusting the temperature of the battery at a time to

based on the assessed temperature adjustment requiring condition of the battery, wherein to is prior to ti. [0016] Such a method provides improved temperature behaviour of the battery while being in use, in particularly when the vehicle which is equipped with a battery is in a driving mode.

[0017] An electrically powered vehicle according to the present invention shall thereby mean a vehicle, which is at least partly powered by a battery or by a battery-based energy storage device. Therefore, such a vehicle may be a fully electrically powered vehicle or a hybrid vehicle, for example.

Examples of such vehicles comprises cars, buses, trains and furthermore.

[0018] Further, batteries in the light of the present invention shall particularly mean secondary batteries and as such rechargeable batteries. Non limiting examples comprise lithium batteries, such as lithium-ion batteries, e.g. LiB batteries.

[0019] In detail, it is known for batteries that often there is a non-homogeneous temperature distribution within the battery, or the battery cell, respectively, such as within lithium-ion-batteries. This may be a consequence of varying thermal diffusion path-lengths to the surrounding cooling media or ambient.

[0020] In fact, temperature differences of exemplarily 16°C or eve more may occur, which may result in significant disadvantages. Such

inhomogeneous temperature distributions may lead to the danger of thermal runaways of the batteries as well as inhomogeneous active material degradation leading to decrease in cell performance and accelerated aging.

[0021] Especially in case a cell is used over years, internal cell imbalance will create uneven cell material degradation. The preferentially used portion of the cell will degrade more rapidly than the further cell composite.

Therefore, reducing the thermal impact of thermal degradation would be an advantageous solution.

[0022] The charging/discharging steps of a battery such as a traction battery are often accompanied with losses in the battery which lead to rising cell temperature. The lifetime of traction batteries and their maximum charging or discharging power is mainly limited by the temperature limit of the battery cells. An intelligent or adaptive battery cooling system is a promising approach to extend or maximize the lifetime of the battery and to increase the rate of charging or discharging.

[0023] According to the present invention, the goal of improving the temperature management is achieved as will be described down below.

[0024] The method may thereby be performed by means of a control unit, such as the generally known battery management system, which is configured for carrying out the respective method.

[0025] According to the present invention, the method comprises the steps of a) detecting location information of the vehicle, which location information give information about the power requirements of the battery at

prospective locations and b) detecting driving information of the vehicle, which driving information give information as to when the vehicle will reach the prospective locations. According to this, parameters are detected which are important factors which allow predicting the working behaviour of a battery and in fact it may be predicted if a charging or discharging action will be required. In fact, in case driving information as well as location information are provided, it is in short analyzed where the vehicle is at the moment and where it will be next. The required power

consumption may be assessed based on the route which will be driven by the vehicle in the future. According to this, it may be assessed at which time in the future the vehicle will most-likely require discharging conditions due to the fact that the power requirements are high, or if charging conditions may be provided. Such an assessment may easily be performed due to the fact that mostly, the location information give important information about the power requirements of the battery at prospective positions and the driving information will give information as to when the vehicle will reach said positions. The word "positions" refers to positions on the vehicle's prospective route. In other words "positions" refers to prospective or oncoming locations of the vehicle.

[0026] With this regard, and according to step c) of the present method, the

method comprises the further step of assessing a temperature adjustment requiring condition of the battery, wherein the temperature adjustment requiring condition of the battery starts at a time ti, wherein ti lies in the future, and wherein the temperature adjustment requiring condition of the battery is assessed based on the location information and the driving information.

[0027] In other words, the present method uses the information obtained in steps a) and b), respectively, and based on this information, step c) of the present invention is performed. It is thus assessed, if the temperature of the battery is required to be adjusted, and thus if the battery requires a cooling or heating step, i.e. a temperature adjustment step, respectively based on the oncoming charging or discharging requirements. This step is thus based on the fact that especially charging or discharging steps often are accompanied with increased temperature formation because of which the temperature should be lowered in order to hold the battery in an advantageous temperature range. On the other hand, some batteries require elevated temperatures in order to work properly, especially in case ambient temperatures are comparably low. Therefore, next to cooling the battery, heating the respective battery may be an option in order to allow the battery providing the required energy in a gentle and effective manner.

[0028] The temperature requiring condition and thus the amount of heating or cooling may thereby be assessed based on the present temperature of the battery which may be detected by generally known temperature sensors. The method as described above may also use the traditional method where temperature measurements in the battery module inform the controller when to cool the battery, in order to react to temperature changes of the battery. Also accounts for time-of-day variations in the ambient environment may be provided.

[0029] It is thus important to know about temperature adjusting requirements at a time ti, wherein ti lies in the future. This information about requirements lying in the future allows the further step d) of the present method according to which the method comprises starting pre-adjusting the temperature of the battery at a time to based on the assessed temperature adjustment requiring condition of the battery, wherein to is prior to ti.

[0030] According to this step, the temperature of the battery is adjusted prior to the point of time at which the temperature adjusting requirement occurs. This allows a very secure operation of the battery due to the fact that an operation of the battery in a temperature range which lies out of the preferred or even required range may be avoided or the risk of the latter may at least be significantly lowered.

[0031] In other words, by starting the temperature adjustment or increasing the respective power even before e.g. a charging or discharging event occurs, the temperature of the battery such as the cell temperature will be kept at an appropriate level before, during and after the respective event. This allows not waiting until the temperature adjustment has to be performed in an answer of a temperature profile measured in a battery, but the respective action may be secured in advance of the requirement, i.e. a pre-adjustment of the temperature is performed. This allows at essentially every situation to hold the battery in the desired temperature range.

[0032] The present method thus allows a concept of 'location-based cooling'.

When the vehicle reaches a certain location, cooling or heating of the battery starts. This location could be indicated by a global positioning system (GPS) or map navigation or some other digital communication to inform the vehicle's control system, such as the battery management system, that cooling or heating and thus a temperature adjustment of the battery should begin.

[0033] The above may allow significantly improving the lifetime of the battery as negative effects and especially increased aging of the battery due to inappropriate temperature ranges may be avoided or at least significantly reduced.

[0034] Further, it may be secured or at least enhanced that the maximum

charging or discharging power may be provided or kept constant over a long working period as well as at different ambient conditions as well as driving conditions. This allows the battery to securely and reliably provide the respective power in case it is required over a long lifetime.

[0035] The above solution is clearly advantageous over providing temperature sensors, only. In fact, providing temperature sensors being installed within the battery, or the battery module, respectively, provides an input for regulating the temperature of batteries. This is a simple and responsive strategy, i.e. for cooling as soon as the cell reaches a certain temperature.

[0036] Temperature adjustment based on temperature sensors, however, uses temperature values measured at one or more suitable positions in the battery and/or in the cooling medium as a trigger to start cooling or as a parameter to set the required cooling capacity. The disadvantage of this approach is the lag time between the charge or discharge event and initiation of cooling. Due to thermal delays, the cell temperature of the cells has already risen before the cooling takes effect. It is thus the thermal delay that ultimately limits the mitigation action.

[0037] This disadvantage is not present according to the present method. In

contrast thereto, like discussed above, due to a pre-adjustment of the temperature of the battery the respective temperature range may be safely secured.

[0038] The temperature adjusting control method as described above may be intended for vehicles for public transport such as buses, trams and other railway vehicles, equipped with a traction battery as an energy storage system for electric or hybrid operation, as they are usually operating on a defined route and with a defined timetable. Thus, the power demand and the charging and discharging events are well-known and mostly

predictable, but also could be applied to any electric vehicle operating on an undefined route as the route information and driving information are known and may be used for performing the above-described method.

[0039] It may be advantageous to especially adapt, e.g. increase, a pre-cooling to the state of health of the battery and thus of the battery age. This may be advantageous as it is well known that as a battery ages, the internal resistance increases. This leads to an increase in the heat generation of a battery, and hence the cooling requirement of that battery is in turn increased. Therefore, the cooling rate of the battery may be programmed to increase as the battery ages. This can be based on historical measurements of the battery or during internal resistance measurements during commissioning or on on-board overvoltage measurements done in real time or following operation. This concept could also be applied to increase over the battery's life i. e. a start and end point of the cooling rate.

[0040] The method improves the battery life according to Arrhenius' equation, which links temperature to chemical reaction rate, the reaction rate doubles for every10°C increase in temperature. Therefore, a battery can theoretically charge and discharge two times faster, however the

irreversible side reactions leading to degradation of the active mass in the battery and ohmic losses will also increase by x2 and finally an improved average efficiency of the battery is provided.

[0041] Further, it may be provided that an increase of the cooling rate is

performed with increased irradiation, the vehicle or at least the battery is subjected to. As the battery enclosure is often exposed directly to the sun and thus to irradiation, the present method may include the further option to begin pre-cooling as soon as a certain radiation rate is detected by a sensor, exemplarily on top of the vehicle. This is also a route to optimize the battery's life based on its surroundings. The irradiation may be an indication for increased temperatures of the battery, which may require improved cooling. With this regard, the ambient temperature, such as hot but also cold temperatures, may as well be a parameter which is used for pre-adjusting the temperature of the battery.

[0042] The method allows an exact and timely regulation of the battery's

temperature, due to the fact that in step c) both the detected location information of step a), which give information about the power

requirements of the battery at prospective locations, as well as the detected driving information of step b), which give information as to when the vehicle will reach the prospective locations, are used to assess the temperature adjustment requiring condition. In other words the

temperature adjusting requiring condition is assessed based on the battery's power requirements and the time at which these power

requirements will occur. Thus, the temperature pre-adjusting can precisely be adapted to any temperature adjusting requiring condition, meaning that the battery temperature can be increased or decreased during an appropriate period of time with an appropriate cooling/heating power dependent on the location and driving information. Such an exact and timely temperature pre-adjusting results in an improved power provision efficiency of the battery system.

[0043] To summarize, a method like described above provides an improved

safety due to the fact that the probability of a thermal runaway in operation is reduced. Further, the long-life stability of the battery is improved as well as the efficiency of power provision.

[0044] According to an embodiment, step d) comprises pre-cooling the battery.

Especially a pre-cooling step as a pre-adjustment of the battery may be advantageous. This is mainly due to the fact that mostly a temperature adjustment is performed by cooling the battery because many actions, such as charging or discharging, are accompanied with a temperature rise. Such a temperature rise, may affect the battery to age in an intensified manner and to provide less energy. Further, increased temperatures may under circumstances lead to a negative security effect which in an extreme case may lead to a thermal runaway. Therefore, the advantages of the present method referring to security, long life properties as well as effectivity may in an advantageous manner be reached by pre-cooling the battery. According to this embodiment, the battery is cooled to a lower temperature level before the requirement, such as a charge or discharge event occurs. This concept handles the problem of thermal lag and resistance within the battery to the potential hot spot location at the battery's core or near the terminal. This cooling strategy is especially helpful for "pulse power" operation as an event typically for public transport, where the battery has to deliver high power for limited period of time (e. g. 10...40 seconds). The set point for the subordinate cooling system control is for example the temperature level for the cooling medium.

[0045] According to a further embodiment, the temperature adjustment requiring condition of the battery comprises a discharging step of the battery.

According to this embodiment, a discharging step mostly is obtained when high power demands are present in an intense manner, which is

accompanied with a comparably high temperature rise. Therefore, again, the advantages of the present method referring to security, long life properties as well as effectivity if power provision may in an advantageous manner be reached by referring to a discharging step as temperature adjusting requiring condition.

[0046] According to a further embodiment, step a) is performed by means of a satellite navigation system. Such a system as well named satnav is well known to the person skilled in the art as a system which provides precise location information based on satellite comprising systems. Exemplarily, such a system may be a GPS based device. According to this

embodiment, the location information may be detected especially exactly and precisely allowing the whole method being performed in an especially exact manner. Apart from that, most vehicles comprise a GPS based device, such as a navigation system, allowing to easily implementing this embodiment in existing systems in a very easy and cost-saving manner. Therefore, this embodiment may be especially advantageous in case step b) is performed by means of a navigation system.

[0047] According to a further embodiment, the location information comprise at least one of the following information: the present location, geographic information, such as gradients and steep rises or steep slopes which require maximum charge (downhill) or maximum discharge rates (uphill), level crossings information, such as when and for how long the level crossings are impassable, traffic lights information, such as when and for how long the traffic lights are impassable, and curves information, such as the radius of the curves. In particular regarding the above information may give exact and precise information about the surrounding of the vehicle allowing a precise prediction of prospective charging and discharging procedures of the battery. It may thereby be provided that one, several or all of the afore-named parameters may be used for assessing the temperature adjusting requirements.

[0048] According to a further embodiment, the driving information comprises at least one of the following information: route information, such as the planned route, e.g. the schedule, i.e. planed stops, time information, such as the present time, which may give a hint for traffic jams, timetable information, which may use e.g. current delays and thus information about the timetable of the vehicle to increase the cooling and provide the maximum battery performance, as well as the location of arrival, speed information, such as the present speed as well as a speed profile of the driver, driving behaviour of the driver, such as the drivers braking and accelerating behaviour, meaning how abruptly the driver performs said actions, which may give a further hint of the requirement of a temperature adjustment. Again, In particular regarding the above information may give exact and precise information about the surrounding of the vehicle allowing a precise prediction of prospective charging and discharging procedures of the battery. It may thereby be provided that one, several or all of the afore-named parameters may be used for assessing the temperature adjusting requirements.

[0049] According to a further embodiment step b) is performed based on a

predefined route. Especially according to this embodiment, when using e.g. the before-named driving information, the temperature-adjustment requirements may be assessed very exact allowing to especially safely hold the battery in a predefined temperature range leading to the above- described advantages. This embodiment may further be combined with detecting location information according to step b) with a navigation system as a predefined route may be saved in the navigation system. Therefore, this embodiment may be implemented in a very easy manner.

[0050] According to a further embodiment, the temperature of the battery is

measured by a temperature sensor and the temperature of the battery is used for assessing the temperature adjusting requiring condition of the battery. According to this embodiment, especially the amount of cooling or heating may be assessed. This may in an advantageous manner be provided in case a profile of temperature rise at given charging or discharging condition is saved in a control system. With this regard, based on the battery temperature it may be assessed especially exactly as to which amount the temperature of the battery has to be adjusted.

[0051] According to a further embodiment the ambient temperature is measured and the ambient temperature is used for assessing the temperature adjusting requiring condition of the battery. This embodiment thus allows to detect the present ambient temperature and based on this present temperature, the requirement of adjusting the temperature of the battery and thus of heating or cooling the battery prior the real requirement may be improved. Especially according to this embodiment, an exact and reliable temperature adjustment may be provided as the real conditions are combined with the assessed requirements for heating or for cooling the battery.

[0052] According to a further embodiment to is in the range of equal or less than 600 s prior to ti. Exemplarily, to may lie in the range of equal or more than 0,001 s prior to ti, preferably equal or more than 1 s prior to ti, for example equal or more than 10s prior to ti. Further exemplarily, to may lie in the range of equal or less than 400s prior to ti, particularly equal or less than 250s prior to ti. The above time scales may be suitable for adequately preheating or pre-cooling the battery. However, the respective time scale may be adjusted to the amount of temperature adjustment required as well as to the respective embodiment.

[0053] To summarize, the present invention describes a method of pro-actively regulating the temperature of a battery-based energy storage system, used as primary or secondary power source in an electric or hybrid vehicle. This battery could be operating on an established route in public transport or freely on an unplanned route. The battery regulates its temperature based on various information including location information and driving information. The proposed method intends to act against the impact of the thermal lag inherent in batteries. This leads to improved security, enhanced aging conditions as well as improved efficiency of the battery.

[0054] With regard to further advantages and technical features of the method as described before, it is explicitly referred to the following description of the system, the figures and the description of the figures.

[0055] The present invention further relates to a system for operating a battery in an electrically powered vehicle, the system being characterized in that the system comprises a control unit being configured for performing a method as described in detail before.

[0056] According to this, the system may comprise a battery, such as a lithium based battery, and may further comprise a unit for adjusting the

temperature of the battery. Such a temperature adjusting unit may be formed as it is essentially known from the prior art and may inter alia comprise a system of channels carrying cooling fluid in order to cool or to heat the battery.

[0057] The temperature adjusting unit may be triggered by a control unit, which may be the battery management system or a further control unit. The control unit is connected to the devices for providing location information as well as driving information of the vehicle. Based on this information, the control unit may assess, or predict, respectively, temperature adjusting requirements lying in the future in order to pre-adjust the temperature of the battery by controlling the temperature adjusting unit like it is described in detail above with regard to the method.

[0058] With this regard, the method steps to be conducted may be converted into a program code, wherein the program code may be implementable in a memory unit of the control unit and may be executable by a processor unit of the control unit.

[0059] According to an embodiment, the system is self-learning. This embodiment may be especially advantageous in case the system is integrated into a vehicle of public traffic. These vehicles often go through the same routes with the same timetables at the same time. According to this, the temperature adjusting requirements may be saved and used for the respective prediction. Such a self-learning effect, however, is not limited to the above example.

[0060] According to a further embodiment, the system is positioned in a vehicle of public transport. Again, these vehicles often go through the same routes with the same timetables at the same time allowing the system and the method to be especially effective. [0061] With regard to further advantages and technical features of the systenn as described before, it is explicitly referred to the description of the method, the figures and the description of the figures.

Brief Description of Drawings

[0062] These and other aspects of the invention will be apparent from and

elucidated with reference to the embodiments described hereinafter.

[0063] In the drawings:

[0064] Fig. 1 shows a typical load profile of a battery during a trip of an

electrically driven vehicle;

[0065] Fig. 2 shows a typical temperature distribution within a battery; and [0066] Fig. 3 shows a diagram illustrating the effect of the present invention.

Detailed Description of the Invention

[0067] Fig. 1 shows a typical load profile of a battery during a trip of an electrically powered vehicle. In detail, the x-axis shows the time in seconds, whereas the y-axis shows the power in kW. Starting at point ti , the battery is in a standby mode or in other words, no charging or discharging is performed. Following time line 1 to point t.2, a discharging step takes place for example in case the vehicle is accelerating. Following time line 2 to point .3, the battery may be in a standby mode, for example in case the vehicle is rolling or it is driven by use of a combustion engine in case a hybrid vehicle is used. After point .3, the battery may undergo different charging steps for example by means of regenerative breaking when the vehicle is breaking. These charging steps may take place at time lines 3 and 5 between times t.3 and t 4 as well as t 4 and ts, respectively, wherein t.3 and t 4 may comprise a limited amount of time even though being shown as a distinct point of time. At time line 4, again, the battery may be in a standby mode, for example in case the vehicle is rolling or it is driven by use of a combustion engine in case a hybrid vehicle is used which may be the same at time line 6. At time line 7, starting at ts, the battery may be discharged again, for example in case the vehicle is accelerated. [0068] It becomes clear that at time lines 1 , 3, 5, and 7, the battery may require a temperature adjustment in the form of a cooling step as a charging and discharging process may lead to the battery to be heated by the respective charging or discharging steps.

[0069] This is shown in detail in figure 2, in which the x-axis exemplarily shows the radius of the battery r in cm, wherein 0 shows the axis of the battery, and the y-axis shows the temperature of the battery in °C. It can be seen that at Tb1 , the battery temperature is stable at room temperature.

However, in case the temperature in the interior of the battery rises to 40°C or over 55°C at Tb2 and Tb3, at the outside of the battery, a temperature being far below these values appears. Such temperature lag may lead to negative influences of the battery such as reduced power, reduced safety as well as reduced lifetime in case a temperature adjustment is based in the temperature measured at the outside of the battery, only.

[0070] The method and the system according to the present invention extend upon the traditional solution according to the prior art comprising measuring the cell temperature and cooling when the temperature threshold is reached. However, the method as described above is a comprehensive approach to battery cooling as it considers external parameters to thermal management of the battery, including the

geography, battery history, and the battery's thermal lag.

[0071] The present method is based on the concept of pre-emptively adjusting the temperature of the battery, with the decision to cool or heat the battery based on location information combined with driving information to strategically advance the temperature adjustment of the battery before a charge or discharge.

[0072] This is shown in detail in figure 3 which is a representation of the present method on the average battery temperature during an acceleration operation (battery discharge) in a traction converter application.

[0073] The upper diagram of fig. 3 shows a load profile of a battery. In detail, the x-axis shows the time in seconds, whereas the y-axis shows the power in kW. In period i) the battery does neither charge nor discharge, in time period ii) the battery undergoes a discharging step and in time period iii), again, the battery does neither charge nor discharge.

[0074] The lower diagram shows the temperature profile of the battery during the respective time periods. In detail, the x-axis shows the time in seconds, whereas the y-axis shows the temperature of the battery in °C. According to line B, a temperature adjustment according to the prior art is performed, whereas according to line C a temperature adjustment according to the present method is performed. It can be seen that due to pre-cooling the battery before the temperature rises, i.e. starting at to and thus prior to ti, the temperature as a whole may be kept significant lower and may thus be hold in the advantageous temperature range of the battery. At every point of time, i.e. at ti, when the discharging step starts, at t.2, when the discharging steps ends as well as at t.3, the temperature of the battery is improved.

[0075] While the invention has been illustrated and described in detail in the

drawings and foregoing description, such illustration and description are to be considered illustrative or exemplary and not restrictive; the invention is not limited to the disclosed embodiments. Other variations to be disclosed embodiments can be understood and effected by those skilled in the art in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements or steps, and the indefinite article "a" or " an" does not exclude a plurality. The mere fact that certain measures are recited in mutually different dependent claims does not indicate that a combination of these measures cannot be used to advantage. Any reference signs in the claims should not be construed as limiting scope.

Reference signs list

1 time line

2 time line

3 time line

4 time line time line time line time line