SE1550115A1

SE1550115A1 - Method and control unit for energy storing in a vehicle

Info

Publication number: SE1550115A1
Application number: SE1550115A
Authority: SE
Inventors: Claesson André; Sjödin Robert
Original assignee: Scania Cv Ab
Priority date: 2015-02-04
Filing date: 2015-02-04
Publication date: 2016-08-05
Also published as: DE102016001214A1

Abstract

Method (500) and control unit (300) in a vehicle (100), for charging an energy storage unit. (110) of a vehicle (100) in a first charging zone (120-1), for reaching a subsequent second charging zone (120-2). The method (500) comprises determining (502) current charging level of the vehicle's energy storage unit (110); calculating (505) required charging level for the vehicle (100) being able to reach the subsequent second charging zone (120-2); estimating (506) remaining time the vehicle (100) will remain within the first charging zone (120-1); and charging (507) the energy storage unit (110) of the vehicle (100) at least up to the calculated (505) required charging level, distributed over the estimated (506) remaining time the vehicle (100) will remain within the first charging zone (120-1).(Publ. Fig. 3)

Description

1 METHOD AND CONTROL UNIT FOR ENERGY STORING IN A VEHICLE TECHNICAL FIELD This document discloses a method and a control unit. More particularly, a method and a control unit is described, for charging an energy storage unit of a vehicle in a first charging zone, enough for reaching a subsequent second charging zone.

BACKGROUND Some vehicles with electrical propulsion system such as e.g. a Plug-in Hybrid Electric Ve- 10 hide (PHEV), a Plug-in Hybrid Vehicle (PHV), a plug-in hybrid or a Battery Electric Vehicle (BEV) require charging of their energy storage systems. This may be implemented using e.g. an overhead pantograph (similar to electrical trains) or an inductive pick up. Typically, some 100 to 200 kW of power is transferred during a few minutes to charge the batteries of the vehicle. Thereby various attractive advantages are reached such as less pollution, re- duced noise from the vehicle, reduced operating costs (as no fuel, or less fuel is used), and time gain during travel (as no stop has to be made for filling up fuel), in comparison with non hybrid vehicles with internal combustion engine.

The vehicle with the electrical propulsion system thus may comprise rechargeable batter- ies, or any other similar energy storage device, that can be restored to full charge by connecting the roof mounted pantograph to a positive overhead contact wire and a negative overhead contact wire, respectively, or by an inductive pick up in the vehicle, wherein energy is transferred from certain energy transfer segments of the road by induction.

In a hybrid vehicle, also an internal combustion engine is comprised. Thereby, the problem of range anxiety associated with all-electric vehicles may be reduced, as the combustion engine works as a backup when the batteries are depleted.

The herein discussed vehicle may comprise e.g. a truck, a bus, a van, a car, a motorcycle, military vehicles or any other similar type of vehicle not running on rails.

The power transfer could be static and/ or dynamic, i.e., at standstill or during driving. A typical situation may be to charge a bus at bus stations, e.g. at some selected bus stations when the bus anyway stop and wait for a certain time period. When the vehicle is a truck, charging may be made at loading/ unloading the vehicle. However, charging may also be made when the vehicles are passing certain energy charging segments during the route of the vehicle. 2 The charging station at e.g. a bus stop may be able to supply for example 200 kW but it may not be the best strategy when considering battery life length to charge at maximum available power all the time. Today there is no strategy on how to charge the battery in the best way taking into account distance to next bus stop, current traffic situation, departure according to bus time schedule, etc.

It thus appear that in order for reaching a practical implementation of vehicles with electrical powertrain, further development is required, providing a solution to the above discussed 10 problems.

SUMMARY It is therefore an object of this invention to solve at least some of the above problems and improve charging of an energy storage unit in a vehicle.

According to a first aspect of the invention, this objective is achieved by a method in a vehicle, for charging an energy storage unit of a vehicle in a first charging zone, for reaching a subsequent second charging zone. The method comprises determining current charging level of the vehicle's energy storage unit. Further, the method comprises calculating re- quired charging level for the vehicle being able to reach the subsequent second charging zone. Also the method comprises estimating remaining time the vehicle will remain within the first charging zone. Furthermore the method also comprises charging the energy storage unit of the vehicle at least up to the calculated required charging level, distributed over the estimated remaining time the vehicle will remain within the first charging zone.

According to a second aspect of the invention, this objective is achieved by a control unit in a vehicle. The control unit is configured for controlling charge of an energy storage unit of a vehicle in a first charging zone, for reaching a subsequent second charging zone. The control unit is also configured for determining current charging level of the vehicle's energy storage unit. Furthermore the control unit is configured for calculating required charging level for the vehicle being able to reach the subsequent second charging zone. In addition the control unit is also configured for estimating remaining time the vehicle will remain within the first charging zone. The control unit is also configured for charging the energy storage unit of the vehicle up to the calculated required charging level, distributed over the estimated remaining time the vehicle will remain within the first charging zone. 3 Hereby, thanks to the disclosed aspects, the energy storage unit in the vehicle is not charged faster, or more, than required for reaching the subsequent charging zone in the route of the vehicle. Thereby, the lifetime of the energy storage unit in the vehicle is prolonged. Also, the risk of queuing at the charging zones of vehicles that charges the energy storage unit a bit extra in order to be certain in order to not run out of electricity charge before reaching the subsequent charging zone. Thereby traffic flow is improved.

Other advantages and additional novel features will become apparent from the subsequent detailed description.

FIGURES Embodiments of the invention will now be described in further detail with reference to the accompanying figures, in which: Figure 1Aillustrates a side view of a vehicle and an inductive energy segment in the road; Figure 1Billustrates a side view of a vehicle with a roof mounted pantograph; Figure 2illustrates an above perspective overview of a scenario where a vehicle with electric powertrain is following a route comprising two energy charging zones; Figure 3illustrates an example of energy charging of an energy charging element in a vehicle according to an embodiment of the invention; Figure 4illustrates an example of energy charging of an energy charging element in a vehicle according to an embodiment of the invention; Figure is a flow chart illustrating an embodiment of a method; Figure 6is an illustration depicting a system according to an embodiment.

DETAILED DESCRIPTION Embodiments of the invention described herein are defined as a method and a control unit, which may be put into practice in the embodiments described below. These embodiments may, however, be exemplified and realised in many different forms and are not to be limited to the examples set forth herein; rather, these illustrative examples of embodiments are provided so that this disclosure will be thorough and complete. 4 Still other objects and features may become apparent from the following detailed description, considered in conjunction with the accompanying drawings. It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the herein disclosed embodiments, for which reference is to be made to the appended claims. Further, the drawings are not necessarily drawn to scale and, unless otherwise indicated, they are merely intended to conceptually illustrate the structures and procedures described herein.

Figure 1A illustrates a scenario with a vehicle 100 driving in a driving direction 105. The 10 vehicle 100 comprises an energy storage device 110, such as e.g. rechargeable batteries. The energy storage device 110, may be charged by inductive electrical transmission from an energy charging zone 120, e.g. in a road 130, according to an embodiment.

However, the energy transfer segment 120 may alternatively be situated above the vehicle 100, even if the subsequent description primarily focus on the embodiment where the energy transfer segment 120 is situated under the vehicle 100, in the road 130.

The vehicle 100 may be e.g. a truck, a bus, a van, a car, a motorcycle, military vehicles, or any other similar type of vehicle not running on rails. The vehicle 100 may be configured for running on a road, in terrain or in water, for example. Further, the vehicle 100 comprises an electrical propulsion system such as e.g. a Plug-in Hybrid Electric Vehicle (PH EV), a Plug-in Hybrid Vehicle (PHV), a plug-in hybrid or a Battery Electric Vehicle (BEV) in different embodiments.

The vehicle 100 may be driver controlled or driverless autonomously controlled vehicles in different embodiments. However, for enhanced clarity, the vehicle 100 is subsequently described as having a driver.

Inductive charging, or wireless charging as it also may be referred to as, uses an electro- magnetic field to transfer energy between two objects, in this case from the energy charging zone 120 to the energy storage device 110 via the inductive pick up in the vehicle 100. The vehicle 100 may be stationary or moving during the charging process. Energy is sent through the inductive coupling to the energy storage device 110 which thereby becomes charged.

The energy charging zone 120 may comprise an induction coil to create an alternating electromagnetic field, and a second induction coil in the vehicle 100, which takes power from the electromagnetic field and converts it back into electrical current to charge the energy storage device 110. The two induction coils in proximity combine to form an electrical transformer. Greater distances between sender and receiver coils can be achieved when the inductive charging system uses resonant inductive coupling.

Induction is an electromagnetic phenomenon that makes it possible to transfer electric energy to the vehicle 100 without direct electric contact with the road surface. Compared to fixed transfer, using a direct contact with the roadway, this will allow flexibility, safety and the potential to deal with snow and ice, which are obvious advantages. Further, by placing 10 the energy charging zone 120 in to the road surface, other traffic is not disturbed or endangered, and may be less aesthetically controversial than a solution based on overhead contact lines/ pantograph.

However, some embodiments of the vehicle 100 may also comprise an additional combustion engine, which gives additional independence from the energy charging zone 120 and the charging level of the energy storage device 110, allowing operation also when the energy storage device 110 is discharged.

Figure 1B illustrates a scenario with an alternative embodiment of the vehicle 100 driving in the driving direction 105. The vehicle 100 comprises the energy storage device 110. The energy storage device 110, may be charged by conductive electrical transmission from an overhead energy charging zone 120 via a roof mounted pantograph 140.

Thus the vehicle 100 comprises an energy storage device 110 in some embodiments, which may be charged by the energy charging zone 120 via the roof mounted pantograph 140. An electric motor in the vehicle 100 is then energised by the energy storage device 110.

An advantage with storing energy in the energy storage device 110 is that the vehicle 100 30 is not required to continuously be attached to the energy charging zone 120.

Some embodiments of the vehicle 100 may also comprise an additional combustion engine, which gives additional independence from the overhead energy charging zone 120, allowing independence from charging zones 120 and charging level of the energy storage device 110. 6 The energy charging zone 120 is situated above the road 130 of the vehicle 100 and may comprise two contact wires, one first contact wire with positive pole and one second contact wire with negative pole, extending in parallel with each other and with the road 130 along at least a segment of the route of the vehicle 100. This differs from the corresponding energy transfer segment of a tram or electric train, which normally uses the track as the return part of the electrical path and therefore needs only one wire and one pole.

The roof mounted pantograph 140 thus comprises two current collectors, or collector shoes as they also may be referred to as. One current collector is dedicated to the first contact 10 wire with positive pole and one current collector is dedicated to the second contact wire with negative pole.

Further, it may be mentioned that the vehicle 100 may have one or several pantographs 140. Further the pantograph 140 may have different designs in different embodiments, such as a symmetrical or diamond-shaped pantograph, a half-pantograph, a Z-shaped pantograph, trolley poles or any similar arrangement. The pantograph 140 may have either a single or a double arm in different embodiments. Further, the two current collectors may be kept jointly by one pantograph 140, or separate pantographs 140 may be used for each current collector in different embodiments.

The pantograph 140 may further be arranged to bring the two current collectors in contact with the respective contact wires, e.g. by applying a substantially upward force on the current collectors, bringing them in contact with the contact wires. Such upward force may be provided by pneumatic means, by hydraulic means, by a spring, by resilience of the mate- rial, by an electric motor, by a mechanical mechanism managed by the driver or similar. A sensor may be configured to measure the pressure force between the current collectors and the contact wires in some embodiments. A control and regulation system may, based on the sensor measurements assure that contact is maintained between the current collectors and the contact wires, also during rough road conditions and bumpy passages, ac- cording to some embodiments.

According to some embodiments, a functionality is provided in order to assist the driver to place the pantograph relative the contact wires of the energy charging zone 120 may be determined by utilising e.g. a sensor and/ or a camera in some embodiments. 7 Further, according to some embodiments, the system may keep track of where the energy charging zones 120 ahead are situated along the route of the vehicle 100, which is further explained in Figure 2.

Figure 2 illustrates an overview example of a scenario wherein an embodiment of the previously presented vehicle 100 is driven along a road 130, or route, in the driving direction 105.

The road 130 does not have one consistent energy charging zone 120 from the starting 10 point to the final destination of the vehicle 100. Instead, when driving along the route, the vehicle 100 comprises an arbitrary number of distinct energy charging zones 120 such as e.g. a first energy charging zone 120-1 and a second energy charging zone 120-2. In this illustrative example, the vehicle 100 may charge the energy storage device 110 while standing still, e.g. at a bus stop or at a loading platform, at the first energy charging zone 120-1. The vehicle 100 may be charged dynamically during transfer while passing the second energy charging zone 120-2.

According to some embodiments, a charging strategy is provided for adjusting energy transfer at the first energy charging zone 120-1 in order to not charge the energy storage device 110 faster, or more, than required for reaching the subsequent second energy charging zone 120-2. A certain safety .

Thereby it is not required to charge the energy storage device 110 more than required to reach the next energy charging zone 120. Thus time is saved and the vehicle 100 does not has to remain at the current energy charging zone 120 more than required. Furthermore, battery life length is increased, by not having to be fully charged at maximum power at maximum power transfer rate all the time.

In order not to charge the energy storage device 110 more than required, nor too little to reach the subsequent energy charging zone 120-2, the energy consumption of the vehicle 100 in order to reach the charging zone 120-2.

In order to estimate the energy consumption, various parameters are collected for estimating the energy consumption. Most important is determining the distance from the current charging zone 120-1, where the vehicle 100 is situated, to reach the next charging zone 120-2 of the route of the vehicle 100. 8 Also, the time period the vehicle 100 will remain in the charging zone 120-1 is estimated, and the estimated energy consumption is charged to the energy storage device 110 over the time period the vehicle 100 is estimated to remain in the charging zone 120-1.

Figure 3 illustrates an example of how the previous scenario in Figure 2 may be perceived by the driver of the vehicle 100 when situated at the first charging zone 120-1.

The vehicle 100 comprises a control unit 300. The control unit 300 is configured for control-10 ling charge of an energy storage unit 110 of the vehicle 100 in the first charging zone 1201, for reaching a subsequent second charging zone 120-2.

The energy consumption for reaching the subsequent second charging zone 120-2 may be made based on the distance between the first charging zone 120-1 and the second charg- ing zone 120-2. That distance may be known and preset, e.g. in case the vehicle 100 is a bus driving a predetermined route. In some cases, the distance to the subsequent charging zone 120-2 may be determined from detailed map data retrieved from a memory or database. The geographical position of the vehicle 100 may be determined by a positioning device in the vehicle 100, which may be based on a satellite navigation system such as the Navigation Signal Timing and Ranging (Navstar) Global Positioning System (GPS), Differential GPS (DGPS), Galileo, GLONASS, or the like.

The geographical position of the positioning device, (and thereby also of the vehicle 100) may be done continuously with a certain predetermined or configurable time intervals ac-cording to various embodiments.

Positioning by satellite navigation is based on distance measurement using triangulation from a number of satellites. The satellites continuously transmit information about time and date (for example, in coded form), identity (which satellite which broadcasts), status, and where the satellite are situated at any given time. GPS satellites sends information encoded with different codes, for example, but not necessarily based on Code Division Multiple Access (CDMA). This allows information from an individual satellite distinguished from the others' information, based on a unique code for each respective satellite. This information can then be transmitted to be received by the appropriately adapted positioning device comprised in the vehicle 100. 9 Distance measurement can according to some embodiments comprise measuring the difference in the time it takes for each respective satellite signal transmitted by the respective satellites to reach the positioning device. As the radio signals travel at the speed of light, the distance to the respective satellite may be computed by measuring the signal propaga- tion time.

The positions of the satellites are known, as they continuously are monitored by approximately 15-30 ground stations located mainly along and near the earth's equator. Thereby the geographical position, i.e. latitude and longitude, of the vehicle 100 may be calculated 10 by determining the distance to at least three satellites through triangulation. For determination of altitude, signals from four satellites may be used according to some embodiments.

Having determined the geographical position of the positioning device (or in another way), it may be presented on a map, where the position of the vehicle 100 may be marked.

However, the energy consumption for reaching the subsequent second charging zone 1202 is computed based on the distance to the second charging zone 120-2, further based on various other parameters that may influence the energy consumption of the vehicle 100, such as e.g. vehicle type, motor type, weight of the vehicle 100, traffic situation between the first charging zone 120-1 and the subsequent second charging zone 120-2, ambient temperature, battery ternperature, predicted climate system requirements, road topology, road curvature, estimated road friction, light requirements, allowance for running a combustion engine, driver input and/ or a safety .

In some embodiments, any, some or all of these parameters may be inserted by the driver, e.g. on a display 310, which may comprise a touch screen or similar in some embodiments.

In the illustrated example, the vehicle 100 is a bus which is standing at a bus stop, wherein the first charging zone 120-1 is situated. The time to departure is displayed to the driver. Also, the driver is requested to estimate the traffic intensity, which may be utilised for estimating the additional energy consumption that will be required for the moment.

Figure 4 again illustrates yet another example of how the previous scenario in Figure 2 may be perceived by the driver of the vehicle 100 according to another embodiment, alter-native to the embodiments illustrated in Figure 3.

The vehicle 100 comprises the control unit 300 for controlling charge of an energy storage unit 110 of the vehicle 100 in a first charging zone 120-1, for reaching a subsequent second charging zone 120-2.

The vehicle 100 may in some embodiments comprise a receiver 320. The receiver 320 may receive wireless signals from a transmitter 330, external to the vehicle 100, which transmitter 390 in turn is in communicative connection with a central node 340, external to the vehicle 100. 10 The central node 340 may determine certain parameters such as e.g. traffic situation, traffic intensity, keep information of bus departure times, distance to subsequent charging zone 120-2, ambient temperature, road topology to the subsequent charging zone 120-2, energy consumption for the vehicle 100 for reaching the subsequent charging zone 120-2, and/ or similar information.

The wireless signal may be e.g. a Vehicle-to-Vehicle (V2V) signal, or any other wireless signal based on, or at least inspired by wireless communication technology such as Wi-Fi, Wireless Local Area Network (WLAN), Ultra Mobile Broadband (UMB), Bluetooth (BT), or infrared transmission to name but a few possible examples of wireless communications.

Figure illustrates an example of a method 500 according to an embodiment. The flow chart in Figure 5 shows the method 500 for use in a vehicle 100, for charging an energy storage unit 110 of a vehicle 100 in a first charging zone 120-1, for reaching a subsequent second charging zone 120-2.

In some embodiments the vehicle 100 comprises an inductive pick up for charging energy from the energy charging zones 120-1, 120-2 in the road 130. The energy charging zones 120-1, 120-2 may comprise an induction coil to create an alternating electromagnetic field while the inductive pick up in the vehicle 100 comprises a second induction coil which takes power from the electromagnetic field and converts it back into electrical current to charge the energy storage device 110. The two induction coils in proximity combine to form an electrical transformer.

In some other embodiments, the vehicle 100 comprises a roof mounted pantograph 140 for charging energy from the charging zones 120-1, 120-2 above the vehicle 100. The energy charging zones 120-1, 120-2 may comprise a first contact wire with positive pole and a therewith parallel second contact wire with negative pole. 11 The roof mounted pantograph 140 comprises, or is attached to a first current collector, dedicated for contact with the contact wire with positive pole and a second current collector, dedicated for contact with the contact wire with negative pole.

The vehicle 100 may be any arbitrary kind of means for conveyance, such as a truck, a bus, a car, a wagon, an elevator, a motorcycle or similar.

In order to correctly be able to charge the energy storage unit 110 of the vehicle 100, the 10 method 500 may comprise a number of steps 501-507. However, some of these steps 501507 may be performed solely in some alternative embodiments, like e.g. step 501, step 503 and/ or step 504. Further, the described steps 501-507 may be performed in a somewhat different chronological order than the numbering suggests. Step 505 may be performed before step 502 for example in some embodiments. The method 500 may comprise the subsequent steps: Step 501, which may be performed only in some alternative embodiments, comprises detecting the vehicle's arrival at the first charging zone 120-1, and initiating the method 500 when the vehicle 100 arrives at the first charging zone 120-1.

In some embodiments, the first charging zone 120-1 may be detected by using a vehicle mounted camera, a laser scanner, an ultrasonic sensor or similar detector on the vehicle 100. It may also, or alternatively be detected based on the geographical position of the vehicle 100 as determined by a positioning device, and also based on retrieval of the posi- tion of the first charging zone 120-1 from a map stored in a memory.

Step 502 comprises determining current charging level of the vehicle's energy storage unit 110, e.g. by measuring the charging level with a volt meter or similar device or estimate it's State Of Charge (SO C).

Step 503, which may be performed only in some alternative embodiments, comprises determining distance to the subsequent second charging zone 120-2.

The distance from the first charging zone 120-1 where the vehicle 100 currently is situated, to the subsequent second charging zone 120-2 may be determined either based on destination of the vehicle 100 extracted from a navigator, or obtained from the driver, or by determining a route the vehicle 100 will follow. In some embodiments, the distance between 12 the first charging zone 120-1 and the subsequent second charging zone 120-2 may be received from a central node 340, or from e.g. a look-up table.

Step 504, which may be performed only in some alternative embodiments wherein step 503 has been performed, comprises estimating energy consumption for reaching the subsequent second charging zone 120-2, based on the determined 503 distance.

The estimation of the energy consumption for reaching the subsequent second charging zone 120-2, may further be based on vehicle type, motor type, weight of the vehicle 100, 10 traffic situation between the first charging zone 120-1 and the subsequent second charging zone 120-2, ambient temperature, battery temperature, predicted climate system requirements, road topology, road curvature, estimated road friction, light requirements, allowance for running an internal combustion engine, driver input and/ or a safety .

The weight of the vehicle 100 may be determined by a weight sensor in the vehicle 100 in some embodiments. However, the vehicle weight may be approximated to a static value in some embodiments, or determined to one value in a set of static values (no cargo/ half loaded/ loaded). In other embodiments, for example when the vehicle 100 is a bus, the number of passengers on the bus may be counted, and an estimated average weight of each passenger may be added to the weight of the vehicle 100. However, in some embodiments the number of passengers on e.g. a bus may be estimated based on statistics, or estimated based on the time of the day, the day of the year etc., as it is known that the number of passengers will increase during rush hours.

The traffic situation between the first charging zone 120-1 and the subsequent second charging zone 120-2 may be based on e.g. a report received from a central node, from information received from another vehicle having passed the relevant route in the opposite direction, by e.g. Vehicle-2-Vehicle (V2V) communication, or other corresponding wireless communication. However, the traffic situation may be estimated based on the number of traffic lights, road conjunctions etc. between the first charging zone 120-1 and the second charging zone 120-2. Further, the traffic situation may be estimated based on statistics, or estimated based on the time of the day, the day of the year etc., as it is known that traffic will be dense during rush hours.

The ambient temperature of the vehicle 100 may be measured by a thermometer in the vehicle 100, or alternatively received from a central node, external to the vehicle 100 (which in turn may measure the ambient temperature by a thermometer). The ambient 13 temperature may be approximated in some embodiments based on time of the year and/ or time of the day. In case the ambient temperature is low, such as below e.g. 10°C, the heat may be turned on in the vehicle 100, which will increase the energy usage. In case the ambient temperature is high, such as exceeding e.g. 25°C, an air conditioning system/ climate system in the vehicle 100 may be turned on, which increase the energy usage.

The battery temperature may be measured by a thermometer arranged in the battery in some embodiments. In some embodiments, the battery temperature may be approximated based on the ambient temperature. Fast charging of most batteries is limited to a tempera- 10 ture of 5°C to 45°C. In case the battery temperature falls below 0°C, it may not be possible to charge the energy storage unit 110 at all.

The predicted climate system requirements may be based on the measured or estimated ambient temperature.

Road topology and/ or road curvature may be calculated based on stored detailed map data, which may be retrieve from a memory or database. Uphill driving will require more energy than downhill driving.

Road friction may be estimated based on the type of surface of the road 130, such as for example asphalt road, unpaved road. Further, icy road or wet leaves on the road may be assumed based on the ambient temperature, and/ or the time of the year.

Furthermore, light requirements may be determined based on legal requirements, and/ or by the light conditions during the time period of the travel between the first charging zone 120-1 and the second charging zone 120-2.

In case the vehicle 100 comprises an additional internal combustion engine besides the electric motor, the possible allowance, or non-allowance, for running the internal combus- tion engine in a certain part of the route between the first charging zone 120-1 and the second charging zone 120-2 may determine the charging. Such areas are sometimes referred to as zero tailpipe emission areas.

Driver input may be any arbitrary input from the driver, based on factors that may influence the energy consumption for reaching the second charging zone 120-2. Perhaps the driver has to take another route than normally due to road work or similar. 14 The safety , to for example 10%-20% of the estimated energy consumption for reaching the second charging zone 120-2. However, the safety . A vehicle 100 having an additional internal combustion engine may have a lower safety 5 dependent only on the charged battery power.

Step 50comprises calculating required charging level for the vehicle 100 to be able to reach the subsequent second charging zone 120-2, based on the computed energy requirements.

In some embodiments, the required charging level may be extracted from a memory, or may be calculated based on the determined 503 distance to the subsequent second charging zone 120-2 and the estimation 504 of energy consumption for reaching the subsequent second charging zone 120-2, based on the determined 503 distance in some embodi- ments.

Step 506 comprises estimating remaining time the vehicle 100 will remain within the first charging zone 120-1. The remaining time may be extracted from e.g. a time table in case the vehicle 100 is a bus.

Step 507 comprises charging the energy storage unit 110 of the vehicle 100 at least up to the calculated 505 required charging level, distributed over the estimated 506 remaining time the vehicle 100 will remain within the first charging zone 120-1.

Thereby the power transfer rate may be kept as low as possible, while still enabling sufficiently charged batteries in the vehicle 100 for reaching the next charging zone 120-2.

Figure 6 illustrates an embodiment of a system 600 for controlling charge of an energy storage unit 110 of a vehicle 100 in a first charging zone 120-1, for reaching a subsequent 30 second charging zone 120-2. The system 600 comprises a set of charging zones 120-1, 120-2, where the energy storage unit 110 in the vehicle 100 may be charged. Further, the system 600 comprises a vehicle 100 with an energy storage unit 110. Also, the system 600 comprises a control unit 300. The control unit 300 may perform at least some of the previously described steps 501-507 according to the method 500 described above and illus- trated in Figure 5.

The control unit 300 is configured for determining current charging level of the vehicle's energy storage unit 110. Also, the control unit 300 is configured for calculating required charging level for the vehicle 100 being able to reach the subsequent second charging zone 120-2. In addition the control unit 300 is configured for estimating remaining time the vehicle 100 will remain within the first charging zone 120-1. The control unit 300 is further configured for charging the energy storage unit 110 of the vehicle 100 up to the calculated required charging level, distributed over the estimated remaining time the vehicle 100 will remain within the first charging zone 120-1. 10 Further, the control unit 300 may optionally be configured also for determining distance to the subsequent second charging zone 120-2. The control unit 300 may be further configured for estimating energy consumption for reaching the subsequent second charging zone 120-2, based on the determined distance.

In some embodiments, the control unit 300 may be configured also for detecting the vehicle's arrival at the first charging zone 120-1, and initiating the method 500 according to steps 501-507 when the vehicle 100 arrives at the first charging zone 120-1.

The control unit 300 may further be configured, in some embodiments, for determining the 20 distance to the subsequent second charging zone 120-2 either based on destination of the vehicle 100 extracted from a navigator or obtained from the driver, or by determining a route the vehicle 100 will follow.

Further, the control unit 300 may further be configured for estimating the energy consump- tion for reaching the subsequent second charging zone 120-2, based on vehicle type, motor type, weight of the vehicle 100, traffic situation between the first charging zone 120-1 and the subsequent second charging zone 120-2, ambient temperature, battery temperature, predicted climate system requirements, road topology, road curvature, estimated road friction, light requirements, allowance for running an internal combustion engine, driver input and/ or a safety .

The control unit 300 may comprise a processor 6configured for performing at least some of the previously described steps 501-507 according to the method 500, in some embodiments.

Such processor 620 may comprise one or more instances of a processing circuit, i.e. a Central Processing Unit (CPU), a processing unit, a processing circuit, a processor, an 16 Application Specific Integrated Circuit (ASIC), a microprocessor, or other processing logic that may interpret and execute instructions. The herein utilised expression "processor" may thus represent a processing circuitry comprising a plurality of processing circuits, such as, e.g., any, some or all of the ones enumerated above.

The control unit 300 may further comprise a receiving circuit 6configured for receiving a signal from a display 310 and/ or a receiver 330 in the vehicle 100 in different embodiments. 10 Furthermore, the control unit 300 may comprise a memory 6in some embodiments. The optional memory 625 may comprise a physical device utilised to store data or programs, i.e., sequences of instructions, on a temporary or permanent basis. According to some embodiments, the memory 625 may comprise integrated circuits comprising silicon-based transistors. The memory 625 may comprise e.g. a memory card, a flash memory, a USB memory, a hard disc, or another similar volatile or non-volatile storage unit for storing data such as e.g. ROM (Read-Only Memory), PROM (Programmable Read-Only Memory), EPROM (Erasable PROM), EEPROM (Electrically Erasable PROM), etc. in different embodiments.

Further, the control unit 300 may comprise a signal transmitter 630. The signal transmitter 630 may be configured for transmitting a control signal to be received by the energy storage unit 110 in the vehicle 100 in some embodiments.

The previously described steps 501-507 to be performed in the control unit 300 may be implemented through the one or more processors 620 within the control unit 300, together with computer program product for performing at least some of the functions of the steps 501-507. Thus a computer program product, comprising instructions for performing the steps 501-507 in the control unit 300 may perform the method 400 comprising at least some of the steps 501-507 for charging an energy storage unit 110 of a vehicle 100 in a first charging zone 120-1, for reaching a subsequent second charging zone 120-2, when the computer program is loaded into the one or more processors 620 of the control unit 300.

The computer program product mentioned above may be provided for instance in the form of a data carrier carrying computer program code for performing at least some of the step 501-507 according to some embodiments when being loaded into the one or more processors 620 of the control unit 300. The data carrier may be, e.g., a hard disk, a CD ROM disc, 17 a memory stick, an optical storage device, a magnetic storage device or any other appropriate medium such as a disk or tape that may hold machine readable data in a non-transitory manner. The computer program product may furthermore be provided as computer program code on a server and downloaded to the control unit 300 remotely, e.g., over an Internet or an intranet connection.

The terminology used in the description of the embodiments as illustrated in the accompanying drawings is not intended to be limiting of the described method 500; the control unit 300; the computer program and/ or the vehicle 100. Various changes, substitutions and/ or 10 alterations may be made, without departing from invention embodiments as defined by the appended claims.

As used herein, the term "and/ or" comprises any and all combinations of one or more of the associated listed items. The term "or" as used herein, is to be interpreted as a mathe- matical OR, i.e., as an inclusive disjunction; not as a mathematical exclusive OR (XOR), unless expressly stated otherwise. In addition, the singular forms "a", "an" and "the" are to be interpreted as "at least one", thus also possibly comprising a plurality of entities of the same kind, unless expressly stated otherwise. It will be further understood that the terms "includes", "comprises", "including" and/ or "comprising", specifies the presence of stated 20 features, actions, integers, steps, operations, elements, and/ or components, but do not preclude the presence or addition of one or more other features, actions, integers, steps, operations, elements, components, and/ or groups thereof. A single unit such as e.g. a processor may fulfil the functions of several items recited in the claims. 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. A computer program may be stored/ distributed on a suitable medium, such as an optical storage medium or a solid-state medium supplied together with or as part of other hardware, but may also be distributed in other forms such as via Internet or other wired or wireless communication system. 18

Claims

1. A method (500) for charging an energy storage unit (110) of a vehicle (100) in a first charging zone (120-1), for reaching a subsequent second charging zone (120-2), wherein the method (500) comprises: determining (502) current charging level of the vehicle's energy storage unit (110); calculating (505) required charging level for the vehicle (100) to be able to reach the subsequent second charging zone (120-2); estimating (506) remaining time the vehicle (100) will remain within the first charging zone (120-1); and charging (507) the energy storage unit (110) of the vehicle (100) at least up to the calculated (505) required charging level, distributed over the estimated (506) remaining time the vehicle (100) will remain within the first charging zone (120-1).

2. The method (500) according to claim 1, further comprising: detecting (501) the vehicle's arrival at the first charging zone (120-1), and initiating the method (500) when the vehicle (100) arrives at the first charging zone (120-1).

3. The method (500) according to any of claim 1 or claim 2, further comprising: determining (503) distance to the subsequent second charging zone (120-2); estimating (504) energy consumption for reaching the subsequent second charg- ing zone (120-2), based on the determined (503) distance.

4. A control unit (300) for controlling charge of an energy storage unit (110) of a vehicle (100) in a first charging zone (120-1), for reaching a subsequent second charging zone (120-2), wherein the control unit (300) is configured for determining current charging level of the vehicle's energy storage unit (110); and further configured for calculating required charging level for the vehicle (100) being able to reach the subsequent second charging zone (120-2); and in addition configured for estimating remaining time the vehicle (100) will remain within the first charging zone (120-1); and configured for charging the energy storage unit (110) of the vehicle (100) at least up to the calculated required charging level, distributed over the estimated remaining time the vehicle (100) will remain within the first charging zone (120-1).

5. The control unit (300) according to claim 4, further configured for detecting the vehicle's arrival at the first charging zone (120-1), and initiating the method (500) according to claim 1 when the vehicle (100) arrives at the first charging zone (120-1). 19

6. The control unit (300) according to any of claim 4 or claim 5, further configured for determining distance to the subsequent second charging zone (120-2); and also configured for estimating energy consumption for reaching the subsequent second charging zone (120-2), based on the determined distance.

7. The control unit (300) according to any of claims 4-6, further configured for determining the distance to the subsequent second charging zone (120-2) either based on destination of the vehicle (100) extracted from a navigator or obtained from the driver, or by determining a route the vehicle (100) will follow.

8. The control unit (300) according to any of claims 4-7, further configured for estimating the energy consumption for reaching the subsequent second charging zone (1202), based on vehicle type, motor type, weight of the vehicle (100), traffic situation between the first charging zone (120-1) and the subsequent second charging zone (120-2), ambient temperature, battery temperature, predicted climate system requirements, road topology, road curvature, estimated road friction, light requirements, allowance for running an internal combustion engine, driver input and/ or a safety .

9. A computer program comprising program code for performing a method (500) ac-cording to any of claims 1-3 when the computer program is executed in a control unit (300) according to any of claims 4-8.

10. A vehicle (100) comprising a control unit (300) according to any of claims 4-8.

11. A system (600) for charging an energy storage unit (110) of a vehicle (100) in a first charging zone (120-1), for reaching a subsequent second charging zone (120-2), wherein the system (600) comprises: a set of charging zones (120-1, 120-2); a vehicle (100) comprising an energy storage unit (110); and a control unit (300) according to any of claims 4-8. 1/6 -.. ml II T-11 MI 1--1,----. -1