WO2020067947A1

WO2020067947A1 - Power supply arrangement with separated power links and method

Info

Publication number: WO2020067947A1
Application number: PCT/SE2019/050787
Authority: WO
Inventors: André Claesson; Robert SJÖDIN; Mathias Björkman; Linus ÄHRLIG
Original assignee: Scania Cv Ab
Priority date: 2018-09-28
Filing date: 2019-08-27
Publication date: 2020-04-02
Also published as: SE542927C2; CN112739579A; SE1851160A1; DE112019004116T5

Abstract

The present disclosure relates to techniques in the context of vehicles, and to a power supply arrangement for use in a vehicle. According to a first aspect, the disclosure relates to a power supply arrangement 400 for use in a vehicle 1. The power supply arrangement 400 comprises at least one energy storage device 70, a first power link 101 and a second power link 102. The at least one energy storage device 70 comprising an energy storage 76 being electrically connectable to a first power connector 71 and a second power connector 72, wherein the second power connector 72 is electrically disconnectable from the first power connector 71. The first power link 101 is arranged to connect the first power connector and at least one propulsion system of the vehicle and the second power link 102 is arranged to connect the second power connector and at least one braking system of the vehicle 1. The second power link 102 is electrically separated from the first power link 101 upon disconnection of the second power connector 72 from the first power connector 71. The disclosure also relates to a vehicle 1 comprising the power supply arrangement and to a corresponding method.

Description

Power supply arrangement with separated power links and method

Technical field

The present disclosure relates to techniques in the context of vehicles, and to a power supply arrangement for use in a vehicle. The disclosure also relates to a vehicle comprising the power supply arrangement, to a corresponding method, a computer program and a computer-readable medium.

Background

Vehicles of today are typically manufactured for a specific purpose, e.g. a bus is manufactured for transporting people and a truck is manufactured for transporting goods. Such vehicles are commonly manufactured and completely assembled in a factory, or they may be partly assembled in a factory and completed at a body manufacturer. Once the vehicle is assembled, the vehicle may be used for the specific purpose. Thus, a bus may be used as a bus and a garbage truck may be used as a garbage truck. Different vehicles are thus needed for different purposes, which may require a large fleet of vehicles for a hauler, and thereby become very costly.

There are, for example, known solutions where a truck can be rebuilt by changing a concrete mixer to a loading platform. This increases the flexibility and two different functions can be achieved by means of one single vehicle. Also, document US- 2018/0129958 A1 discloses a modular electric vehicle using interchangeable vehicle assembly modules. The user can thereby disassemble and reassemble the vehicle for use in different applications. However, in the future, further development towards even more flexible vehicle solutions might be needed to meet customers’ different vehicle needs in a cost-efficient way.

Energy for propelling electrical vehicles may be stored in special batteries configured to provide a high system voltage, e.g. 650 volt. The batteries need to be secure due to the high energy content. The vehicles’ braking systems have similar requirements for power supply. In modular vehicle solutions, it may be advantageous to let several or all of the modules of a vehicle share one energy source. Consequently, the propulsion and the braking systems of a vehicle may have to share one common energy source. However, to let a propulsion system and a braking system of a vehicle share one energy source may imply security risks.

Summary

It is an object of the disclosure to provide a solution that enables sharing of one energy source between one or more braking and propulsion systems in a vehicle, while assuring high security. For example, it is an object to assure that a single error, such as a short circuit, cannot propagate between the systems. It is a further object to provide a solution that is suitable for use in modular vehicle solutions.

According to a first aspect, the disclosure relates to a power supply arrangement for use in a vehicle. The power supply arrangement comprises at least one energy storage device, a first power link and a second power link. The at least one energy storage device comprising an energy storage being electrically

connectable to a first power connector and a second power connector, wherein the second power connector is electrically disconnectable from the first power connector. The first power link is arranged to connect the first power connector and at least one propulsion system of the vehicle and the second power link is arranged to connect the second power connector and at least one braking system of the vehicle. The second power link is electrically separated from the first power link upon disconnection of the second power connector from the first power connector. Thereby, vehicle design can be simplified by letting the braking systems and propulsion systems share one single energy storage device while security is still ensured due to the separated power links as a single error in one of the systems will not propagate to the other system. More specifically, the proposed power supply arrangement makes it possible to, e.g. in case of an error, completely isolate one of the power links from the other power link and thereby maintain full functionality on the other power link. In addition, as the propulsion system may typically operate as an auxiliary braking system, this implies that if the main braking systems fails, then the auxiliary braking system will be able to continue to operate, and vice versa. In some embodiments, the at least one energy storage device comprises at least one switch configured to be controlled to disconnect the first power connector from the second power connector. Thereby, the power links can easily be separated.

In some embodiments, the at least one energy storage device comprises a control unit configured to evaluate a predefined error criterion and to control the at least one switch to disconnect the first power connector from the second power connector upon the predefined error criterion being fulfilled. Thereby, different error criteria can be used to trigger the electrical separation of the first and second power connectors.

In some embodiments, the control unit is configured to obtain data indicative of a current flowing through the first and/or second power links and the predefined error criterion comprises that the obtained current meets one or more predefined thresholds. Thereby, a current peak cannot propagate between the systems.

In some embodiments, the power supply arrangement comprises at least two energy storages, and wherein the first and second power links are arranged to parallel connect the at least two energy storages. Thereby, stacked batteries can be used to power several propulsion and braking systems, which makes system design less complex as the power links can then connect more than one power source.

In some embodiments, the vehicle is assembled by a set of modules. The set of modules comprises at least one drive module comprising a pair of wheels, a propulsion system and the at least one brake system; wherein the at least one drive module is configured to be autonomously operated, and at least one functional module. Each module in the set of modules comprises at least one interface releasably connectable to a corresponding interface of another module.

In these embodiments, the first and second power links are arranged to connect the at least one energy storage device, being arranged in one of the at least one modules, and at least one propulsion system and one brake system being arranged in one of the other modules. By providing each energy storage device with two independent power links, it is ensured that regardless of whether the drive modules are stand-alone or connected to a functional module, the brake function is always separated from the propulsion function.

In some embodiments, the first power link is arranged to connect the at least one energy storage device and a plurality of propulsion systems of the vehicle and wherein the second power link is arranged to connect the at least one power source and a plurality of brake systems of the vehicle. Hence, all the power links in the vehicle are connected, which facilitates power supply and charging.

According to a second aspect, the disclosure relates to a vehicle comprising at least one propulsion system, at least one brake system and the power supply arrangement of the first aspect. The power supply arrangement is arranged to connect the at least one energy storage device and the at least one propulsion system and the at least one brake system.

In some embodiments, the vehicle comprises a set of modules. The set of modules comprises at least one drive module comprising a pair of wheels, a propulsion system and the at least one brake system. Each module in the set of modules comprises at least one interface releasably connectable to a

corresponding interface on another module. The first and second power links are arranged to connect an energy storage device being arranged in one of the at least one modules and at least one propulsion system and brake system being arranged in one of the other modules in the set of modules.

In some embodiments, the first and second power links are arranged to connect an energy storage device being arranged in one of the functional modules and at least one propulsion system and brake system being arranged in one of the drive modules.

According to a third aspect, the disclosure relates to a method for use in a control unit of an energy storage device comprising an energy storage being electrically connected to a first power connector connectable to a propulsion system of a vehicle and a second power connector connectable to a braking system of a vehicle. The method comprises evaluating a predefined error criterion and disconnecting the first power connector from the second power connector upon the predefined error criterion being fulfilled.

In some embodiments, the method comprises obtaining data indicative of a current flowing through the first and/or second power links and the predefined error criterion comprises that the current meets one or more predefined

thresholds.

According to a fourth aspect, the disclosure relates to a computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method according to the third aspect.

According to a fifth aspect, the disclosure relates to a computer-readable medium comprising instructions which, when executed by a computer, cause the computer to carry out the method according to the third aspect.

Brief description of the drawings

Fig. 1 illustrates a set of modules, a vehicle assembled from the set of modules, and an offboard system.

Fig. 2a - Fig. 2c schematically illustrate a drive module in a side view, a front view and in a view from above.

Fig. 3 schematically illustrates a drive module in further detail in a side view.

Fig. 4 schematically illustrates a side view of a functional module comprising a power control arrangement.

Fig. 5 illustrates the power storage device in further detail.

Fig. 6 illustrates an example implementation of a power supply arrangement.

Fig. 7 illustrates a control unit of a power supply arrangement.

Fig. 8 illustrates a corresponding method for use in a control unit of an energy storage device.

Detailed description

One way of meeting customers’ different vehicle needs in a flexible and cost- efficient way is to use a modularised vehicle assembled from a set of modules. Such a modularised vehicle is typically assembled at the customer’s premises and the customer may thus buy a set of modules from a manufacturer. The modular vehicle can easily be assembled and re-assembled e.g. to perform a certain mission. Even though a vehicle is modular, i.e. assembled by independent units, it may be desirable to power all the modules using one single power supply, e.g. a battery pack. This means that one battery pack is used for both propelling and braking the vehicle.

In order to enable the same battery pack to be used for both propelling and a braking without risking security, this disclosure proposes a power supply arrangement, for use in a vehicle, where the propulsion system(s) and the braking system(s) have separate feed circuits. More specifically, a solution is proposed where one or more propulsion systems and one or more braking systems are connected to separate connectors of a battery pack, herein referred to as battery storage device, via separate power links. Furthermore, switches or similar are arranged in the power storage device(s) to ensure that the power links of the individual (propulsion and braking) systems can be separated, so that a single error in one of the systems does not propagate to the other system. Thereby, the power links between the energy storage and the different systems in the vehicle are completely separated. Because each battery pack has two independent power connectors that are connected to two separate power links, one for each system, it is ensured that regardless of whether the drive modules are stand-alone or paired with a functional module to form a complete vehicle, the brake function is always separated from the propulsion function.

The term“power link” refers herein to an electrical connection which is typically an electrical conductor that allows the flow of an electrical current in one or more directions. The electrical conductor is e.g. a cable or wire. A power link may be assembled by several electrically connected sub links (or parts).

For better understanding of the proposed technique the concept of assembling a vehicle from modules will now be explains with reference to the example embodiment of Fig. 1 .

Fig. 1 illustrates an example set of modules 20 for assembling a vehicle 1. An offboard system, herein referred to as a first control device 100, and an example of an assembled vehicle 1 are also illustrated. The set of modules 20 comprises a plurality of drive modules 30 and a plurality of functional modules 40.

The drive modules’ 30 main function is typically to drive (e.g. propel, steer and brake) a vehicle 1 . The drive modules 30 comprise a pair of wheels 37 and are configured to be autonomously operated. The functional modules are configured to perform a certain function such as to carry a load, e.g. goods or people. Each module 30, 40 in the set of modules 20 comprises at least one interface 50 releasably connectable to a corresponding interface 50 of another module 30, 40.

By combining drive modules 30 and functional modules 40 different types of vehicles 1 can be achieved. Some vehicles 1 require two or more drive modules 30 and some vehicles 1 only require one drive module 30, depending on the structural configuration of the functional module 40. Each drive module 30 comprises a control device, herein referred to as a second control device 200, and may thus communicate with a control center or off-board system, i.e the first control device 100. Since the drive modules 30 may be configured to be operated as independently driven units by means of the second control devices 200, the drive modules 30 may be connected to, or disconnected from, the functional module(s) 40 without manual work.

The principle of assembling a vehicle 1 from modules 30, 40 will now be described. An operator may receive a mission from a client to transport goods from one location to another. The operator enters the information about the mission into the first control device 100 via a user interface, such as a touch screen or similar. It is pointed out that this is merely an example, and the received mission may automatically be translated and/or inputted to the first control device 100. The first control device 100 then determines which function to be performed and thus which type of vehicle 1 is required to complete the mission. In this example, the required vehicle 1 may be a truck. The first control device 100 selects which modules 30, 40 to use for the required truck. The type of vehicle 1 and the modules 30, 40 required to complete the mission may for example be selected based on information about the goods, the distance to travel and/or the geographical location. The first control device 100 then converts the mission into a command for one or two selected drive modules 30 to physically and electrically connect with the selected functional module 40. In this example, the vehicle 1 comprises two drive modules. The second control devices 200 of the drive modules 30 each receives the command and converts the command to control signals for the respective drive module 30. The drive modules 30 are thereby controlled to physically and electrically connect with the functional module 40. Controlling the drive module 30 to connect with a functional module 40 may comprise controlling the drive module 30 to identify the position of the selected functional module 40 and move to that position. The position of the selected functional module 40 may be determined based on information received in the command to connect the drive module 30 with the functional module 40. Alternatively, the command to connect the drive module 30 and the functional module 40 is transmitted to both the drive module 30 and the functional module 40, whereby the functional module 40 prepares for the connection and starts transmitting a signal. The drive module 30 may then determine the position of the functional module based on this transmitted signal. The drive modules 30 are thus autonomously operated to find the selected functional module 40 and connect with that functional module 40. At least one sensor device 60 arranged at the drive modules 30 and/or the functional module 40 may be configured to sense when the physical and/or electrical connection has been performed. The at least one sensor device 60 may send a signal to the second control device 200 indicating that the connection(s) have been performed. Based on the signal from the at least one sensor device 60, the second control device 200 may send a verification signal to the first control device 100 for verification of the connection(s). The first control device 100 may then generate a unique vehicle identity for the assembled vehicle 1 . A vehicle 1 is thus assembled and the vehicle 1 is ready to perform the mission. The generated unique vehicle identity may then be stored in a database or record associated with the offboard-system, i.e. the first control device 100. The generated unique vehicle identity may also be transmitted to the modules 30,40 of the vehicle 1 . The unique vehicle identity may optionally be displayed by one or more of the modules 30, 40 of the vehicle 1 .

Fig. 2a - Fig. 2c schematically illustrate a drive module 30 in a side view, a front view and in a view from above, according to an embodiment. The drive module 30 comprises a body 38. The wheels 37 are arranged on two opposite sides of the drive module 30. The body 38 may have a first and a second side 31 , 32, which are facing in opposite directions. The body 38 may have a third and a fourth side 33, 34, which are facing in opposite directions, wherein the third side 33 and the fourth side 34 may extend perpendicular to the first and the second sides 31 , 32. The body 38 may also have a fifth and a sixth side 35, 36, which are facing in opposite directions. The fifth and the sixth sides 35, 36 may extend perpendicularly to the first and the second sides 31 , 32 and the third and fourth sides 33, 34. The first and the second sides 31 , 32 may be referred to as side surfaces. The third and the fourth sides 33, 34 may be referred to as front and rear surfaces respectively. The fifth side 35 may be referred to as a top surface and the sixth side 36 may be referred to as a bottom surface. The sides 31 , 32, 33, 34, 35, 36 may each have a shape that is flat or curved and may be shaped with indentations and/or protrusions. Instead of the perpendicularly extension of the sides 31 , 32, 33, 34, 35, 36 described above, the sides 31 , 32, 33, 34, 35, 36 may extend at any angle in relation to each other.

Fig. 3 schematically illustrates a drive module 30 in further detail in a side view. The drive module 30 comprises at least one (only one illustrated) propulsion system 91 , at least one (only one illustrated) braking system 92, an interface 50 and a control device, i.e. a second control device 200. The propulsion system(s) 91 comprises for example an electric machine(s) connected to the wheels 37. In some embodiments, each wheel 37 is individually driven by its own electric machine

The braking system(s) 92 comprises, for example, standard disc brakes and electromechanical actuators that require reliable power supply. The braking system 92 is typically the primary braking system of the vehicle 1 .

However, because the braking system 92 may in some situations be insufficient or fail for some reason, a secondary braking system is generally required. Also disc brakes may be worn out if used too frequently. Therefore, the electric machine(s) of the propulsion system(s) 91 in some embodiments operate as generators that generate electric energy while braking the wheels 37. Thus, the propulsion system(s) is in some embodiments operates as a secondary or auxiliary braking system of the vehicle 1 .

In some embodiments the drive module 30 comprises at least one energy storage unit (not shown) for providing the propulsion system 91 with energy. The energy storage unit is for example an electric battery that may be recharged with electric energy. Alternatively, when the electric battery is discharged, the electric battery may be replaced by another charged electric battery. The energy storage unit may be of limited size and insufficient to supply power to the propulsion system 91 and the braking system 92 while operating the vehicle 1. In some embodiments the energy storage in the drive module 30 is mainly used while assembling the vehicle 1 and/or transporting the drive module 30 without load.

The second control device 200 is configured to operate the drive module 30 as an independently driven unit. The drive module 30 may transport itself without any externally driven unit such as a towing vehicle. The drive module 30 may transport itself by means of the at least one propulsion system 91 . The drive module 30 may be configured to be autonomously operated. Thus, the second control device 200 may be configured to control the operation of the drive module 30. The second control device 200 may be configured to transmit control signals to the various systems and components of the drive module 30 for controlling for example the steering and the propulsion of the drive module 30. The second control device 200 may be configured to operate the drive module 30 autonomously based on received commands. The second control device 200 may thus be configured to receive commands from a remotely located off-board system, i.e. the first control device 100, and to convert the commands into control signals for controlling the various systems and components of the drive module 30. The second control device 200 may also be configured to receive data about the surroundings from at least one sensor (not shown) and based on this data control the drive module 30. The second control device 200 may be implemented as a separate entity or distributed in two or more physical entities. The second control device 200 may comprise one or more computers. The second control device 200 may thus be implemented or realised by a processor and a memory. The drive module 30 may be configured to be releasably connected to either a second drive module 30 and/or a functional module 40 for forming an assembled vehicle 1 . At least one of the sides 31 , 32, 33, 34, 35, 36 of the drive module 30 may thus have a shape that allows the drive module 30 to be releasably connected to the second drive module 30 and/or the functional module 40.

The at least one interface 50 of the drive module 30 is configured to physically connect the drive module 30 with a second drive module 30 and/or a functional module 40. The interface(s) 50 of the drive module 30 may be releasably connectable to a corresponding interface 50 of a second drive module 30 and/or a functional module 40.

In Fig. 1 and Fig. 3, the drive modules 30 are illustrated with only one interface 50, on one side of the drive module 30. However, it is to be understood that each drive module 30 may comprise a plurality of interfaces 50 for releasable connection with other modules 30, 40. The interface(s) 50 of the drive modules 30 may be arranged on different sides of the drive module 30 and thus enable connection with other modules 30, 40 on multiple sides of the drive module 30. The interfaces 50 on the drive modules 30 and the functional modules 40 respectively, are arranged on corresponding positions to enable connection between the modules 30, 40.

In some embodiments, the at least two interfaces 50 comprises electric interfaces, arranged for transferring electric power and/or transmitting electric signals between the drive module 30 and another module e.g. to a functional module 40 to which the drive module is connected. The electrical interface 50 may be a wired interface 50 or a wireless interface e.g. a conductive interface 50. In other words, by connecting the drive module 30 and the functional module 40 electrically the modules 30, 40 may transfer power between each other and share information. The drive module 30 may, for example, control parts of the functional module 40, such as opening and closing of doors, heating and cooling.

Fig. 4 schematically illustrates a side view of a functional module 40, where the proposed solution may be implemented. The functional module 40 may be provided with wheels, but generally a functional module 40 cannot move on its own. Instead, the functional module 40 needs to be connected to at least one drive module 30 to be able to move. The functional module 40 may comprise a space 41 for accommodating or supporting a load. The at least one functional module 40 may be configured for transporting goods and may thus function as a truck when being assembled with at least one drive module 30. In some embodiments, the functional module 40 comprises a control device, which hereinafter will be referred to as a third control device 300. The third control device 300 of the functional module 40 may be configured to communicate with the off-board system mentioned in connection to Fig. 1 . The third control device 300 may also be configured to communicate with the second control device 200 of the drive module 30.

The functional module 40 of Fig. 4 also comprises a power supply arrangement 400 comprising one or more power storage devices 70 and power circuitry (illustrated by the dashed lines). In the example of Fig. 4 the power supply arrangement 400 comprises three power storage devices 70. Even though a connected drive module 30 might also comprise an energy storage it may not comprise enough energy to propel and brake the entire vehicle 1 to accomplish missions. Hence, when operating the vehicle, the energy storage devices 70 of the functional module 40 typically supplies power to the drive modules 30 via the interface 50. In other words, the power storage devices 70 are configured to supply power to one or more of the drive modules 30 of the vehicle 1 . In this example, the power storage devices 70 are configured to supply power to the propulsion system(s) 91 and the braking system(s) 92 of two connected drive modules 30. In some embodiments the propulsion system may also, as described above, operate as an auxiliary braking system of the vehicle 1 . The power circuity, which is only schematically illustrated by dashed lines in Fig. 4, will be described in further detail in Fig. 5 and Fig. 6.

In a modular vehicle, such as the modular vehicle of Fig. 1 , construction and weight may be simplified if independent propulsion and braking systems distributed among independent modules 30, 40 share one common energy storage. Thus, the effects of the proposed power supply arrangement 400 are particularly noticeable when implemented in such a vehicle. Therefore, the proposed power supply arrangement 400 will herein be described in the context of the modular vehicle 1 of Fig. 1 , Fig. 2 and Fig. 3. However, it must be appreciated that the proposed power supply arrangement 400 may in general be used in any vehicle, where one or more power storage devices 70 jointly supplies power to both a propulsion system and a braking system of the vehicle.

The modular vehicle 1 of Fig. 1 , which is herein used to describe the proposed technique, is assembled by two drive modules 30 and a functional module 40. In other words, the drive modules 30 and the functional module 40 constitute the vehicle 1 . Consequently, the components of those modules 30, 40 together constitute the vehicle 1 . In other words, the components of the drive modules 30 and the functional module 40 may be considered to be the components of the vehicle 1 and are therefore, for simplicity, herein referred to as simply “the components of the vehicle G. For example, the propulsion system 91 or brake system of one of the drive modules 30 of the vehicle 1 is herein referred to as the propulsion system 91 or brake system 92 of the vehicle 1 .

The proposed power supply arrangement 400 will now be described in with reference to Fig. 4, Fig. 5 and Fig. 8.

The proposed technique is applicable on all sorts of road and off-road vehicles. Flowever, the disclosure may relate to heavy vehicles, such as buses, trucks etc. Specifically, the present disclosure may relate to vehicles for use on public roads.

Fig. 6 illustrates an example implementation of a power supply arrangement 400. The power supply arrangement 400 comprises three energy storage devices 70 (here denoted 70a, 70b and 70c), a first power link 101 and a second power link 102. In this example, the power supply arrangement 400 comprises three energy storage devices 70. Flowever, it must be appreciated that the proposed technique could be used for any number of energy storage devices 70, including one single power storage device 70. The power supply arrangement 400 is e.g. arranged in a functional module 40 of a vehicle 1 , as illustrated in Fig. 4. Parts of the power supply arrangement 400 (e.g. the power links) may also extend to the drive modules 30, e.g. via the interfaces 50.

Fig. 5 illustrates a power storage device 70 in further detail. The energy storage device 70 is e.g. arranged in a functional module 40 of a modular vehicle 1 . The energy storage device 70 is e.g. a“battery pack”. The term“battery pack” is often used in conjunction with electric vehicles. A battery pack is a set of any number of energy storages e.g. (preferably) identical batteries or individual battery cells. The energy storages may be configured in a series, parallel or a mixture of both to deliver the desired voltage, capacity, or power density. The energy storage device 70 or“battery pack” is typically rechargeable. For simplicity, the energy storage device 70 illustrated in Fig. 4 only comprises one energy storage 76, here illustrated as a battery. In addition to the energy storage 76, the at least one energy storage device 70 comprises a first power connector 71 and a second power connector 72.

The energy storage 76 is arranged to supply power to the first and second power connectors 71 , 72. In other words, energy storage 76 is electrically connectable to the first power connector 71 and a second power connector 72.

The power connectors 71 , 72 are the electrical contacts used to connect a load or charger to the energy storage device 70. These contacts may have a wide variety of designs and sizes. More specifically, the first power connector 71 is configured to connect one or more propulsion systems 91 of the vehicle 1 to the battery storage device 70 and the second power connector 72 is configured to be connected to one or more braking systems 92 to the battery storage device 70. The power connectors 71 , 72 typically have one positive terminal (denoted“+” in Fig. 4) and one negative terminal (denoted in Fig. 4).

The energy storage device 70 may also comprise further circuitry. In this example embodiment, the circuitry comprises, switches 73a, 73b, 75a, 75b, two fuses 74a, 74b, sensor 78, a pre-charge resistor circuit 79, a control unit 80 and electrical lines 77.

The switches 73a, 73b, 75a, 75b are controllable. In other words, they are configured to receive control signals and open and close in response to the control signals. Two of the controllable switches 73a, 73b are arranged between the positive terminal of the energy storage 76 and the positive terminals of the first power connector 71 and second power connector 72 respectively. These switches are typically used to connect the energy storage 76 to the respective systems e.g. at power up when starting the vehicle 1 . The pre-charge resistor circuit 79 is used to limit the inrush current during the power up procedure. However, when two different devices (such as a braking system and a propulsion system) are simultaneously connected to the same energy storage (or power supply) this typically means that the devices are also interconnected. This is a possible security problem as errors, such as current peaks, may propagate between the devices. Therefore, energy storage device 70 is configured such that the second power connector 72 is electrically disconnectable from the first power connector 71. In the disconnected state no current may flow between the first and second power connectors 71 , 72. To achieve this, it is generally not enough that only the positive terminals are disconnected, but also the negative terminals need to be disconnected. More specifically, in the example embodiment of Fig. 5, two further controllable switches 75a and 75b are arranged between the negative terminal of the energy storage 76 and the negative terminal of the first power connector 71 and second power connector 72 respectively. In this way, when an error occurs on one of the power connectors 71 , 72 (or in a device connected thereto), then that power connector, may be completely disconnected from both the energy storage device 70 and the other connector, by opening both the switch at the positive terminal and the switch at the negative terminal of the power connector where the error was detected. For example, if an error occurs in the propulsion system 91 , then the first power connector 71 is disconnected by opening the switch 73a at the positive terminal of the first power connector 71 and the switch 75a at the negative terminal of the first power connector 71. Thereby, the error cannot propagate to the braking system 92 and the braking system 92 may continue to operate and to receive power from the energy storage devices 70. Once the error is fixed, the first power connector 71 can be reconnected. In other words, the switches 73a, 73b, 75a, 75b are configured to be controlled to (completely) disconnect the first power connector 71 from the second power connector 72. The switches 73a, 73b, 75a, 75b are e.g. contactors. A contactor is an electrically-controlled switch used for switching an electrical power circuit. A contactor is typically controlled by another circuit, e.g. the control unit 80.

The fuses 74a, 74b are e.g. used as a complement to the switches 75a, 75b at the negative terminals when the current is too large to be interrupted by e.g.

contactors. The fuses 74a, 74b may be passive fuses or controllable fuses, also called pyro fuses. Hence, it must be appreciated that there are many different ways to arrange components to obtain a disconnection of the power connectors 71 , 72 e.g. by different combinations of fuses and contactors.

The control unit 80 which may be referred to as an Internal Battery Unit, IBU, is e.g. an Electrical Control Unit, ECU. Fig. 7 illustrates the control unit 80 in more detail. In some embodiments, the control unit 80 is a“unit” in a functional sense. The hardware basically comprises various electronic components on a Printed Circuit Board, PCB. The most important of those components is typically a processor 81 e.g. a microprocessor, along with a memory 82 e.g. EPROM or a Flash memory chip. The software (also called firmware) is typically lower-level software code that runs in the microcontroller. The control unit 80 is configured to control the functionality of the energy storage device 70. In particular, it is configured to control the connection and disconnection of the first and second power connectors 71 ,72.

In some embodiments, the control unit 80 is configured to control the switches 73a, 73b, 75a, 75b when an error condition occurs e.g. the error is indicated by sensors or blown fuses in battery cells of the energy storage device 70, in a connected propulsion system 91 or anywhere in the vehicle 1 . An error condition is e.g. an abnormal current flow at one of the first and second power connectors 71 , 72 or in the corresponding systems connected to thereto. In some

embodiments, the control unit 80 obtains sensor data from one or several sensors 78 in the energy storage device 70 to detect the error. For example, the one or several sensors 78 are configured to measure a current flowing through the first and second power connectors 71 , 72.

In some embodiments, the control unit 80 is configured to evaluate a predefined error criterion and to control the at least one switch 73a, 73b, 75a, 75b to disconnect the first power connector 71 from the second power connector 72 upon the predefined error criterion being fulfilled. For example, the control unit 80 is configured to obtain data indicative of a current flowing through the first and/or second power links 101 , 102. The data is e.g. sensor data provided by the sensors 78 Then the predefined error criterion might be that the obtained current meets one or more predefined thresholds. More specifically, this means that a metric or other quantity representing the current meets the threshold. For example, the condition may be that the current does not go beyond a predefined threshold value e.g. 150 A.

Now turning back to Fig. 6, the other parts of the power supply arrangement 400 will be described. The first power link 101 is a power circuit that electrically connects the first power connectors 71 of the energy storage devices 70a, 70b, 70c and one or more propulsion systems 91 of the vehicle 1 . The second power link 102 is typically a connector that electrically connects the second power connectors 72 of the energy storage devices 70a, 70b, 70c and one or more braking systems 92 of the vehicle 1 . Thus, the first and second power links 101 , 102 are arranged in the functional module 40 and may extend to the drive module 30 via the interface 50. In other words, the interface 50 and the drive module 30 also comprises two separated power links for the propulsion system(s) and the braking system(s). In other words, the first power link 101 is arranged to

electrically connect the first power connectors 71 and at least one propulsion system 91 of the vehicle 1 and the second power link 102 is arranged to

electrically connect the second power connectors 72 and at least one braking system 92 of the vehicle 1 . The first power link 101 and the second power link 102 are e.g. cables or lines. The first power link 101 and the second power link 102 may be implemented as one physical cable package. Flowever, in any case, no current can flow between the power links when one of the power links 71 , 72 is disconnected from the power storage 76 . In other words, the power links 101 ,

102 are only electrically connected via the power storage 76. Stated differently, when the second power connector 72 is disconnected from the first power connector 71 then the second power link 102 is electrically separated from the first power link 101 .

For example, if the power the vehicle 1 is assembled by a set of modules 20 as illustrated in Fig. 1 -3 then, in some embodiments, the first and second power links 101 , 102 are arranged to connect the at least one energy storage device 70, being arranged in one of the at least one modules 30, 40 and at least one propulsion system 91 and one brake system 92 being arranged in one of the other modules 30, 40. In other words, the first and second power links may be arranged to connect energy storage devices 70 and systems of a plurality of modules 30, 40 of a modular vehicle.

When the power supply arrangement 400 comprises more than one energy storage device 70, which is the case in the example of Fig. 5, then the first and second power links 101 , 102 are in some embodiments arranged to connect all the energy storage devices 70 to the propulsion system(s) and the braking system(s) of the vehicle. For example, the first and second power links 101 , 102 are arranged to parallel connect the at least two energy storages 70a, 70b, 70c. Flence, even in the case where the vehicle comprises several energy storages 70a, 70b, 70c, the energy storages 70a, 70b, 70c it is possible to completely isolate one of the power links 101 , 102 from the other if one of the power links is short-circuited and keep full functionality on the other power link.

It is appreciated that modular vehicles as described in Fig. 1 may typically comprise several drive modules 30 having independent propulsion and braking systems 91 , 92. For simplicity it is generally desirable to use one common energy storage device 70 for all the systems. This is achieved by connecting the power links in the entire vehicle 1 i.e. in several or all the drive modules 30 of a modular vehicle. More specifically, if the vehicle 1 comprises a plurality of propulsion systems 91 , the first power link 101 is arranged to connect the first power connector 71 and two or more or all of the plurality of propulsion systems 91 . Also, if the vehicle 1 comprises a plurality of brake systems 92 then the second power link 102 is arranged to connect the second power connector 72 and two or more or all of the plurality of brake systems 92.

Fig. 8 illustrates a corresponding method for use in a control unit 80 of an energy storage device 70 comprising an energy storage 76 being electrically connected to a first power connector 71 connectable to a propulsion system 91 of a vehicle 1 and a second power connector 72 connectable to a braking system 92 of a vehicle 1 . The method is e.g. implemented by a software program, comprised in memory 82, executed by the processor 81 of the control unit 80 illustrated in Fig.

5. In some embodiments the method comprises obtaining SO data indicative of a current flowing through the first and/or second power links 101 , 102. The data is e.g. sensor data read from sensors 78. The data may also be received from other parts of the vehicle. For example, the data may indicate a or other error in the propulsion system.

The data is then evaluated to decide whether one of the systems needs to be disconnected from the energy storage device 70. In other words, the method comprises evaluating S1 a predefined error criterion. For example, the error criterion comprises that the current meets one or more predefined thresholds.

This basically means that if the current flowing through one of the power connectors is alarming (e.g. above a certain current level), then the error criterion is considered fulfilled. Further examples of the evaluation principle have already been described in connection with Fig. 5.

The method further comprises disconnecting S2 the first power connector 71 from the second power connector 72 upon the predefined error criterion being fulfilled. In other words, when an alarming condition is detected at the power connectors (or in loads or chargers connected thereto), then the malfunctioning power connector is disconnected to avoid that the error propagates to the other connector. If the error occurs in the braking system 92, then the propulsion system may then be controlled to operate as an emergency brake to brake the vehicle 1. The proposed technique could of course also be implemented for three or more power connectors, if needed.

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; control arrangement or computer program. Various changes, substitutions and/or alterations may be made, without departing from invention embodiments as defined by the appended claims.

The term“or” as used herein, is to be interpreted as a mathematical 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 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.

Claims

1. A power supply arrangement (400) for use in a vehicle (1 ), the power

supply arrangement (400) comprising:

- at least one energy storage device (70) comprising an energy storage (76) being electrically connectable to a first power connector (71 ) and a second power connector (72), wherein the second power connector (72) is electrically disconnectable from the first power connector (71 ),

- a first power link (101 ) arranged to connect the first power connector

(71 ) and at least one propulsion system (91 ) of the vehicle, and

- a second power link (102) arranged to connect the second power

connector (72) and at least one braking system (92) of the vehicle (1 ), wherein the second power link (102) is electrically separated from the first power link (101 ) upon disconnection of the second power connector

(72) from the first power connector (71 ).

2. The power supply arrangement (400) according to claim 1 , wherein the at least one energy storage device (70) comprises at least one switch (73a, 73b, 75a, 75b) configured to be controlled to disconnect the first power connector (71 ) from the second power connector (72).

3. The power supply arrangement (400) according to any of the preceding claims, wherein the at least one energy storage device (70) comprises a control unit (80) configured to evaluate a predefined error criterion and to control the at least one switch (73a, 73b, 75a, 75b) to disconnect the first power connector (71 ) from the second power connector (72) upon the predefined error criterion being fulfilled.

4. The power supply arrangement (400) according to claim 3, wherein the control unit (80) is configured to obtain data indicative of a current flowing through the first and/or second power links (101 , 102) and

wherein the predefined error criterion comprises that the obtained current meets one or more predefined thresholds.

5. The power supply arrangement (400) according to any of the preceding claims, wherein the power supply arrangement (400) comprises at least two energy storages (70a, 70b, 70c), and wherein the first and second power links (101 , 102) are arranged to parallel connect the at least two energy storages (70a, 70b, 70c).

6. The power supply arrangement (400) according to any of the preceding claims, wherein the at least one energy storage device (70) comprises a battery package.

7. The power supply arrangement (400) according to any of the preceding claims, wherein the vehicle (1 ) is assembled by a set of modules (20), the set of modules (20) comprising:

at least one drive module (30) comprising a pair of wheels (37), a propulsion system and the at least one brake system (92); wherein the at least one drive module (30) is configured to be autonomously operated, and

at least one functional module (40),

wherein each module (30; 40) in the set of modules (20) comprises at least one interface (50) releasably connectable to a corresponding interface (50) of another module, and wherein the first and second power links (101 , 102) are arranged to connect the at least one energy storage device (70), being arranged in one of the at least one modules (30, 40), and at least one propulsion system (91 ) and one brake system (92) being arranged in one of the other modules (30, 40).

8. The power supply arrangement according to any of the preceding claims, wherein the first power link (101 ) is arranged to connect the at least one energy storage device (70) and a plurality of propulsion systems (91 ) of the vehicle (1 ) and wherein the second power link (102) is arranged to connect the at least one power source (70) and a plurality of brake systems of the vehicle (1 ).

9. A vehicle (1 ) comprising: - at least one comprising a propulsion system (91 ),

- at least one brake system (92) and

- the power supply arrangement (400) according to any one of claims 1 -8, wherein the power supply arrangement (400) is arranged to connect the at least one energy storage device (70) and the at least one propulsion system (91 ) and the at least one brake system (92).

10. The vehicle of claim 9, wherein the vehicle (1 ) comprises a set of modules (20), the set of modules (20) comprising:

at least one drive module (30) comprising a pair of wheels 37, a propulsion system and the at least one brake system (92); wherein the at least one drive module (30) is configured to be autonomously operated, and

at least one functional module (40),

wherein each module (30; 40) in the set of modules (20) comprises at least one interface (50) releasably connectable to a corresponding interface (50) on another module,

and wherein the first and second power links are arranged to connect an energy storage device (70) being arranged in one of the at least one module (30, 40) and at least one propulsion system and brake system being arranged in one of the other modules (30, 40) in the set of modules.

11. The vehicle of claim 10, wherein the first and second power links are

arranged to connect an energy storage device (70) being arranged in one of the functional modules (30) and at least one propulsion system and brake system being arranged in one of the drive modules (40).

12. A method for use in a control unit (80) of an energy storage device (70) comprising an energy storage (76) being electrically connected to a first power connector (71 ) connectable to a propulsion system of a vehicle (1 ) and a second power connector (72) connectable to a braking system of a vehicle (1 ), the method comprising: - evaluating (S1 ) a predefined error criterion and

- disconnecting (S2) the first power connector (71 ) from the second power connector (72) upon the predefined error criterion being fulfilled.

13. The method according to claim 12 comprising:

- obtaining (SO) data indicative of a current flowing through the first and/or second power links (101 , 102) and

wherein the predefined error criterion comprises that the current meets one or more predefined thresholds.

14. A computer program comprising instructions which, when the program is executed by a computer, cause the computer to carry out the method of any one of the claims 12 to 13.

15. A computer-readable storage medium comprising instructions which, when executed by a computer, cause the computer to carry out the method of any one of the claims 12 to 13.