TECHNICAL FIELD

The present disclosure relates to the field of thermal management of power supplies and in particular to thermal management of power supplies such as those used in lighting arrangements. More specifically, the present disclosure relates to thermal management wherein thermal transport is switchable using an electrically controllable relay.

BACKGROUND

The lifetime of a power supply (used to provide power to for example a lighting arrangement) may depend on temperature. If the power supply for example includes a battery, the battery may be prone to a number of charging/discharging cycles that the battery may sustain before a replacement is needed. Said number of charging/discharging cycles may for example depend on the temperature of the battery during

charging/discharging. By controlling the temperature of the power supply, the lifetime of the power supply may therefore be optimized. See for example US4999576A, which discloses to use a thermoelectric working module therefor.

However, the ambient conditions where the power supply is used may change with time, and depend e.g. on time of day or time of year. Thus, there is a need for an improved and more flexible thermal management of such power supplies. SUMMARY OF THE INVENTION

The present disclosure seeks to at least partially fulfill the above requirements. To achieve this, a power supply arrangement as defined in the independent claim provided. Further embodiments of the power supply arrangement are provided in the dependent claims. The present disclosure also relates to a battery chamber and a lighting arrangement.

According to one aspect of the present disclosure, a power supply arrangement is provided. The power supply arrangement may include a power supply, a heat exchange surface, an electrically controllable relay, a first path arranged to allow heat transfer between the power supply and the electrically controllable relay, and a second path arranged to allow heat transfer between the electrically controllable relay and a heat exchange surface. The electrically controllable relay may be operable in at least a first state and in a second state for dynamically managing a temperature of the power. The electrically controllable relay may be adapted to, when in the first state, bridge the first path and the second path to provide a heat transfer between the power supply and the heat exchange surface. The electrically controllable relay may be further adapted to, when in the second state, disconnect the first path and the second path. If the first path and the second path are disconnected, the heat transfer between the power supply and the heat exchange surface may be blocked or at least restricted.

The electrically controllable relay may be an electrically controllable mechanical relay, or be phrased as an electrically controllable mechanical relay.

For safety, for ensuring that the heat exchange surface may by no means be electrically loaded, in some examples, the first path and the second path may be electrically isolating.

The electrically controllable relay may assist in, at will, allowing or disallowing heat transfer between the power supply and e.g. an ambient air via the heat exchange surface. This provide a way of dynamically managing the temperature of the power supply to a desired level (or to within a desired interval) even if the temperature of e.g. an ambient air surrounding the power supply arrangement is changing (and is e.g. season- dependent and/or time- dependent). During summer, for example, the electrically controllable relay may be closed (e.g. by applying a control signal which operates the relay in the first state) such that heat from the power supply may escape to the ambient air via the heat exchange surface, thereby allowing sufficient cooling of the power supply. During winter, the electrically controllable relay may be opened (e.g. by supplying a control voltage which operates the relay in the second state, and/or by for example supplying no control voltage at all) such that the outside air is not allowed, or at least to a lesser extent able, to cool the power supply too much. The supply of a suitable control signal (e.g. a control voltage) may for example be achieved through the use of a switch which may be operated manually, or for example, as will be described later herein in more detail, by means of a controller or similar.

The power supply may generate heat. The power supply may be a heat source, depending on the operations and the applications the power supply drives, such as e.g. light sources. Heat of the power supply may be transferred over said first and second path.

If the temperature of (or at) the power supply is higher than desired, and the temperature of e.g. an ambient air at the heat exchange surface is lower than the temperature of the power supply, the relay may be electrically controlled to be in the first state, and heat may be transferred from the power supply to the ambient air via the heat exchange surface. This may cool the power supply to a desired temperature. Likewise, if the temperature of (or at) the power supply is lower than desired, and if the temperature of the ambient air at the heat exchange surface is higher than the temperature of the power supply, the relay may be electrically controlled to be in the first state, and heat may be transferred from the ambient air to the power supply via the heat exchange surface. This may help to heat the power supply to a desired temperature.

If the temperature of (or at) the power supply is at a desired temperature, i.e. such that no cooling or heating of the power supply is deemed necessary, the relay may be electrically controllable to be in the second state. This may help to prevent the temperature of the power supply from either decreasing or increasing due to the ambient air surrounding the power supply arrangement.

In an embodiment, the electrically controllable mechanical relay may comprise an electrical insulator, wherein the electrical insulator electrically isolates the first path and the second path. Thus, whereas the first path and the second path are electrically isolated, the configuration of the first path, the second path and the relay still provide a thermally conductive path, which allows for heat transfer. This embodiment provides safety to the power supply arrangement, because it is ensured that by no means the heat exchange surface will be electrically loaded.

According to some embodiments, the power supply arrangement may further include a relay controller. The relay controller may be configured to cause the electrically controllable relay to operate in the first state or in the second state based on at least one condition. The relay controller may for example include a digital processor which may receive one or more input signals and output a relay control signal for electrically controlling the relay based on the one or more input signals. The relay controller may also, in addition or instead, contain one or more analog components which may be connected to produce and output such a relay control signal based on the one or more input signals. It is also envisaged that the relay controller may produce and output the relay control signal based on other properties in addition to, or instead of, the one or more input signals. Such other properties may for example include a software running on the relay control, or hardware included in or connected to the relay controller. The relay controller may be connected to the electrically controllable relay using wired (such as by cable) or wireless (such as by radio or optical) techniques, or a combination thereof. By operating the relay using the relay control, heat transfer to/from the power supply may be alio wed/disallo wed based on the at least one condition. This may for example improve dynamical thermal management of the power supply and the power supply arrangement, and allow for the relay to be operated in a suitable state without requiring e.g. a manual operation of a switch or similar.

According to some embodiments, the at least one condition may include at least one of: a detected temperature at the power supply and/or at the heat exchange surface, a condition whether the power supply is supplying or receiving electric power, a time, and/or a forecasted weather. It is also envisaged that the at least one condition may include additional, or other, properties.

According to some embodiments, the relay controller may be configured to operate the electrically controllable relay in the first state or in the second state so as to keep a temperature at the power supply within a certain temperature interval. The temperature at the power supply may for example correspond to the detected temperature at the power supply referred to with regards to the at least one condition. It may be noted that the relay controller may also be configured to operate the electrically controllable relay so as to keep the temperature at the power supply within the certain temperature interval without using e.g. a detected temperature at the power supply. For example, it is envisaged that the power supply may e.g. rely only on time and/or a forecasted weather and/or other conditions not including a detected temperature at the power supply.

According to some embodiments, the certain temperature interval may correspond to a comfort temperature of the power supply.

According to some embodiments, the relay controller may be configured to operate the electrically controllable relay in the first state or in the second state so as to cool the power supply if the detected temperature at the power supply exceeds an upper boundary of the certain temperature interval, and to heat the power supply if the detected temperature at (or of) the power supply falls below a lower boundary of the certain temperature interval. Herein, when referring to heating or cooling of the power supply it is meant that the relay is operated such that heat transfer to/from the power supply is allowed. Whether the power supply is then really heated or cooled will depend on for example the temperature of the ambient air at the heat exchange surface.

According to some embodiments, the power supply arrangement may further include at least one temperature sensor for detecting the detected temperature at e.g. the power supply and/or the heat exchange surface. The temperature sensor may be connected to the relay controller. The temperature sensor may for example be arranged and configured to measure the temperature at the power supply, at the heat exchange surface, at the ambient air surrounding the power supply arrangement, or similar. The power supply arrangement may include one or more such temperature sensors, and a reading from one or more temperature sensors may be transferred to the relay controller using e.g. wired (e.g. via cable) or wireless (e.g. via radio/optics) techniques.

The use of the temperature sensor provides the possibility to operate or not the relay such that, if the detected temperature at the heat exchange surface is not higher than the detected temperature of the power supply (or is not sufficiently high) and the power supply would require a higher temperature to reach its comfort temperature, then the relay is not operated in the first state and remains open.

According to some embodiments, at least one or both of the first path and the second path may be a heat conductive path and/or a heat convective path. A heat conductive path and/or heat convective path may help to provide sufficient heat transfer to/from the power supplyA heat conductive path may for example be/include a metallic path. A metallic path may for example be of a metal having sufficient heat conductive properties such as e.g. copper, aluminium or other suitable metals. It is also envisaged that a metallic path may contain several layers, and that all layers need not be of the same metal. It is also envisaged that, if the metallic path is layered, that some layers may be non-metallic. A heat conductive path and heat convective path may for example be/include a heat pipe. A heat convective path may for example be/include a thermosiphon. In an embodiment, said heat conductive path may be electrically isolating.

The first path and the second path may be a heat conductive element made of a material being one of a ceramic or a composite. Said composite may for example be a polymer with a thermally conductive filler / fiber. The cross-section of said first path and/or said second path (or phrased as the heat conductive element) may at least be 12.5 square centimeters, or preferably at least be 50 square centimeters. As partly mentioned, in embodiments, said first path and the second path may be electrically isolating. For example, said first path and said second path may comprise an insulating element, which may be thermally conductive, but not electrically conductive, such as a ceramic part.

According to some embodiments, the heat conductive path may be a metallic path including a metallic wire. The metallic wire may be unshielded or shielded, and it is envisaged that the heat transfer properties of the wire may be tailored as desired by e.g. varying the material, the cross-section shape, the cross-section size and/or the shielding material(s) of the wire. The cross-section of said metallic wire may at least be 12.5 square centimeters, or preferably at least be 50 square centimeters. The metallic wire may comprise an electrical insulator, such as a section (of the metallic wire) made of an electrically insulating material, wherein the electrical insulator is still thermally conductive similar to the thermal conductivity of the metallic wire. This ensures safety as mentioned.

According to some embodiments, the power supply may include at least one of a battery, a charge controller and an LED driver. The battery, if included, may be used to provide power to a device connected to the power supply arrangement, such as for example a lamp or other types of lighting devices. The battery may be rechargeable or non- rechargeable. The charge controller, if included, may be used to charge a battery which may or may not be part of the power supply arrangement. The LED driver, if included, may be used to drive one or more LEDs connected to the power supply arrangement. It is also envisaged that the power supply may include other components, and that heat may be transferred to/from these other components as desired via the first and second paths, the electrically controllable relay and the heat exchange surface.

According to some embodiments, the power supply may include a battery, and the battery may be a lithium-based battery. It is also envisaged that the battery may be of another type. Such another type of battery may still have its own corresponding comfort temperature and/or comfort temperature interval, and thus benefit (in terms of e.g. life time and/or capacity) from being included in a power supply according to the present disclosure.

According to some embodiments, the electrically controllable relay may be a vacuum relay. A vacuum relay may provide an improved thermal resistance when in the second state, such that no or little heat is allowed to be transferred to/from the power supply via the relay.

In some embodiments, the electrically controllable relay may be for example an electromagnetic relay, wherein an electromagnetic field is used to move a mechanical switch which may open/close a connection between terminals of the relay. The mechanical switch may be metallic, and the switch may function as a bridge which bridges the first path and the second path when the relay is operated in the first state. It is also envisaged that other types of electrically controllable relays may be used, as long as they may be operated in at least a first state wherein heat transfer between two terminals of the relay is allowed, and a second state wherein heat transfer between the two terminals of the relay is disallowed or at least restricted. According to some embodiments, the first path (which may be metallic) may be connected to an enclosure and/or a heatsink of the power supply. If, for example, the power supply includes or is a battery, the first path may be connected to an enclosure of the battery. If, for example, the power supply includes or is a charge controller and/or an LED driver, the first path may be connected to an enclosure of the charge controller and/or LED driver, and/or to e.g. cooling fins (or other forms of heat sinks) mounted on the enclosure of the charge controller and/or LED driver, and similar.

According to some embodiments, the second path may be connected to an enclosure of the power supply arrangement, and the heat exchange surface may be a surface of such an enclosure of the power supply arrangement.

In some embodiments, for example, the power supply arrangement may further comprise a light source. Hence, the power supply arrangement may be a power supply of a light source. In such examples, the power supply arrangement may further comprise a heat sink, wherein the heat sink is both in contact with the light source and in contact with the power supply, such that heat from the light source may be transferred to the power supply; thereafter for example, the heat from the power supply may be transferred away to a heat exchange surface according to the aspects of the invention. Hence it is advantageous to also manage the heat generated by the light source in combination with heat generated by e.g. the power supply.

According to one aspect of the present disclosure, a battery chamber is provided. The battery chamber may include a power supply arrangement as described herein. The battery chamber may include a thermally insulated enclosure which may be the enclosure of the power supply arrangement, and the power supply may include at least one battery.

According to one aspect of the present disclosure, a lighting arrangement is provided. The lighting arrangement may include a power supply arrangement as described herein and a luminaire which may include at least one light source. The power supply may include a battery for providing power to the at least one light source. The heat exchange surface may be a surface of the luminaire.

According to some embodiments, the luminaire may be arranged to be mounted in a false ceiling. A false ceiling may for example be a ceiling which is installed below a true ceiling, such that a "ceiling space" forms between the true ceiling and an upper side of the false ceiling, and such that a "room space" forms between a lower side of the false ceiling and a floor of the room. The power supply arrangement and the heat exchange surface may be arranged to lie on different sides of the false ceiling. For example, the power supply arrangement may be arranged to lie on the upper side of the false ceiling, in the ceiling space, and the heat exchange surface may be arranged to lie on the lower side of the false ceiling, and be a surface of the luminaire which faces the room space.

The present disclosure relates to all possible combinations of features recited in the claims. Further objects and advantages of the various embodiments of the present disclosure will be described below by means of exemplifying embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Exemplifying embodiments will be described below with reference to the accompanying drawings, in which:

Fig. 1 illustrates a power supply arrangement according to embodiments of the present disclosure;

Fig. 2 illustrates a power supply arrangement according to embodiments of the present disclo sure;

Fig. 3 illustrates a battery chamber according to embodiments of the present disclosure, and

Fig. 4 illustrates a lighting arrangement according to embodiments of the present disclosure.

In the drawings, like reference numerals will be used for like elements unless stated otherwise. Unless explicitly stated to the contrary, the drawings show only such elements that are necessary to illustrate the example embodiments, while other elements, in the interest of clarity, may be omitted or merely suggested. As illustrated in the figures, the sizes of elements and regions may be exaggerated for illustrative purposes and, thus, are provided to illustrate the general structures of the embodiments.

DETAILED DESCRIPTION

Exemplifying embodiments will now be described more fully hereinafter with reference to the accompanying drawings. The drawings show currently preferred

embodiments, but the invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided for thoroughness and completeness, and fully convey the scope of the present disclosure to the skilled person. With reference to Figures 1 and 2, power supply arrangements according to some embodiments are described in the following.

Figure 1 illustrates a power supply arrangement 100. The power supply arrangement includes a power supply 110 and an electrically controllable relay 120. A first path 130 is arranged between the power supply 110 and the relay 120, and a second path 140 is arranged between the relay 120 and a heat exchange surface 150. The relay 120 is electrically controllable by e.g. a relay control signal input on an input wire 122, such that the relay is operable between a first state and a second state. In the first state, the relay 120 may close such that a physical connection (a bridge) is formed between the first path 130 and the second path 140. When bridging the two paths 130 and 140, heat is allowed to flow between the power supply 110 and the heat exchange surface 150 via the two paths 130, 140 and the relay 120. In the second state, the relay 120 may open and break (disconnect) the physical connection between the first path 130 and the second path 140, such that no or little heat may be transferred between the power supply 110 and the heat exchange surface 150 via the two paths 130, 140 and the relay 120.

The heat exchange surface 150 may not be a part of the power supply arrangement 100 itself, but form part of a system into/to which the power supply arrangement 100 is integrated/connected. It is also envisaged that the heat exchange surface 150 may form a part of the power supply arrangement 100 itself. In both cases, the heat exchange surface 150 may for example form part of an enclosure or similar. The heat exchange surface 150 may be a surface which is in contact with an ambient air, and serve to release heat transferred from the power supply 110 into the ambient air, and/or serve to absorb heat, which will be transferred to the power supply 110, from the ambient air. The heat exchange surface 150 may for example be flat, but it is also envisaged that the heat exchange surface 150 may be equipped with for example cooling fins or similar to further improve heat exchange with the ambient air.

The first path 130 and the second path 140 may for example be metallic wires, with properties (such as cross-section shape, cross-section size, wire material and optional shielding) adapted to allow sufficient heat transfer between the power supply 110 and heat exchange surface 150 when the relay 120 is operated in the first state.

The power supply 110 may for example include or be a battery, a charge controller and/or an LED driver, or similar power devices.

Figure 2 illustrates a power supply arrangement 200. The power supply arrangement 200 has a power supply 210 (e.g. a battery, charge controller or LED driver, or similar), an electrically controllable relay 220, a first path 230 and a second path 240. As in the power supply arrangement 100 illustrated in, and described above with reference to, Figure 1, the combination of the relay 220 and the first and second paths 230 and 240 respectively may allow for a switchable heat transfer between the power supply 210 and a heat exchange surface 250. In addition, the power supply arrangement 200 includes a relay controller 260, which may output a relay control signal for electrically controlling the relay 220. The relay control signal is transferred to the relay 220 using the wire 222. It is also envisaged that the relay control signal may be, instead or in addition, transferred to the relay 220 using e.g. a wireless link (such as a radio or an optical link).

The power supply arrangement 200 further includes two temperature sensors

270 and 272 which are connected to the relay controller 260 via wires 274 and 276 respectively. The temperature sensor 270 is arranged to detect a temperature at the power supply 210, and the temperature sensor 272 is arranged to detect a temperature at the heat exchange surface 250. Based on the detected temperatures from the temperature sensors 270 and 272, the relay controller 260 may operate the electrically controllable relay 220 into either one of the first and second states. For example, if a temperature at the power supply 210 is detected to be higher than a desired value, the relay controller 260 may operate the relay 220 into the first state such that heat transfer is allowed between the power supply 210 and the heat exchange surface 250. The relay controller 260 may for example operate the relay 220 into the first state independently of the temperature detected at the heat exchange surface 250 by the temperature sensor 272, or first check that the temperature at the heat exchange surface 250 is lower than the temperature at the power supply 210 such that heat may be transferred from the power supply 210 to the heat exchange surface 250 (and to an ambient air) in order to cool the power supply 210.

Likewise, the relay controller 260 may operate the relay 220 into the second state, in order to disconnect the power supply 210 from the heat exchange surface 250 such that no heat is transferred there between via the first and second paths 230 and 240 respectively. More detailed examples of possible operation of the relay controller 260 will be described later herein.

With reference to Figure 3, a battery chamber including a power supply arrangement is described in the following.

Figure 3 illustrates a battery chamber 300 including a power supply arrangement as described in the preceding embodiments. The power supply arrangement includes a power supply 310 including a battery 312 and a charge controller 314, and further includes an electrically controllable relay 320. The battery 312 and the charge controller 314 are connected to the relay 320 through first paths 330 and 331, and the relay 320 is connected to a heat exchange surface 350 through second paths 340 and 341. The battery chamber 300 includes a thermally insulated enclosure 352, in which the power supply arrangement is located, and the heat exchange surface 350 forms part of the outer side of the thermally insulated enclosure 352. At the location where the second paths 340 and 341 are connected to the heat exchange surface 350, the heat exchange surface 350 contains fins to further improve heat transfer to an ambient air surrounding the thermally insulated enclosure 352 of the battery chamber 300.

The relay 320 has two separate poles, where the first path 330 and the second path 340 are connected to one of the two poles, and the first path 331 and the second path 341 are connected to the other of the two poles. The relay 320 contains two relay switches such that two paths may be closed (or opened) at the same time. This allows the relay 320 to bridge (or disconnect) the first path 330 to (or from) the second path 340, and to bridge (or disconnect) the first path 331 to (or from) the second path 341. The relay 320 is operable in a first state wherein both the battery 312 and the charge controller 314 are thermally connected to the heat exchange surface 350 via the paths 330, 331, 340, 341 and the relay 320. The relay 320 is also operable in a second state wherein neither one of the battery 312 and the charge controller 314 is thermally connected to the heat exchange surface 350 via the paths 330, 331, 340, 341 and the relay 320.

It is also envisaged that the relay switches of the relay 320 may be controlled individually, such that the relay 320 may have more than two states, such as for example four states, wherein the two additional states involve thermally connecting only one of the battery 310 and the charge controller 312 to the heat exchange surface 350 at a time.

It is also envisaged that all of the paths 330, 331, 340, 341 may be connected to a same pole of the relay 320, and that a single relay switch of the relay 320 may be used to connect the first path 330 and the second path 340, and the first path 331 and the second path 341. In such a situation, the relay 320 may have only a single pole.

To electrically control the relay 320 to operate in its respective states, the power supply arrangement includes a relay controller 360 which may output a relay control signal to the relay 320 using the wire 322. The power supply arrangement (or the battery chamber 300) also includes two temperature sensors 370 and 372, which are connected to the relay controller 360 via wires 374 and 376 respectively. The temperature sensor 370 is arranged to measure at least one temperature at the power supply 310. It is envisaged that the temperature sensor 370 may measure a single temperature for both the battery 312 and the charge controller 314, but it is also envisaged that the temperature sensor 370 may provide separate temperatures at the battery 312 and at the charge controller 314. In the latter case, the temperature sensor 370 may for example be two separate sensors located at the battery 312 and the charge controller 314, respectively.

The temperature sensor 372 is arranged to measure a temperature at the heat exchange surface 372. Also here it is envisaged that the temperature sensor 372 may provide more than one temperature, e.g. temperatures for both the heat exchange surface 350 itself and also for the ambient air a bit further away from the heat exchange surface 350, if required.

An example scenario of how the power supply arrangement may help to manage the temperature within the battery chamber 300 may be as follows. It may be envisaged that the battery chamber 300 is mounted outdoors, and that the battery 312 is charged with solar power (provided from an external solar panel) with the help of the charge controller 314 for approximately 8 hours a day during summer season. The charge controller 314 may have a limited efficiency, such that some of the power provided to the charge controller 314 for charging the battery 312 is lost as heat which may increase the temperature of the charge controller 314. In addition, the battery 312 itself may be less than optimal, and some of the power delivered to it from the charge controller 314 may also be lost as heat, heating up the battery 312. The combined heat loss during charging may give rise to a temperature increase within the battery chamber 300 and the thermally insulated enclosure 352.

The optimal temperature for e.g. the battery 312 may be within a certain temperature interval, wherein the lifetime (counted for example in the number of

charging/discharging cycles the battery 312 may sustain before its efficiency decreases or a replacement/repair is needed) is improved/maximized. If the battery is a lithium-based battery, an acceptable such a certain temperature interval may for example be 10-35°C, with an even more suitable interval being 22-30°C. A certain temperature interval suitable for a battery (such as the battery 312) may be referred to as a "comfort (temperature) interval" or a "comfort temperature" for the battery in question.

During summer season, the temperature-increase within the battery chamber 300 due to charging/discharging may therefore raise the temperature of the battery above the certain temperature interval. When the relay controller 360 determines that this is the case (e.g. by measuring the temperature of the battery using the temperature sensor 370), the relay controller 360 may operate the relay 320 to the first state such that a heat transfer path is opened between the battery 312 (and charge controller 314) and the heat exchange surface 350. Heat may therefore be transferred away from the battery 312 such that the battery 312 is cooled below the upper limit of the certain temperature interval. Once the temperature of the battery 312 is determined (e.g. by measuring the temperature using the temperature sensor 370) low enough, the relay controller 360 may operate the relay 320 in the second state, and break the heat transfer path such that no further cooling of the battery 312 is available, at least for some time.

The relay controller 360 may also operate the relay 320 in either of the first or second state based on also the temperature measured outside the thermally insulated enclosure 352, e.g. as measured at the heat exchange surface 350 by the temperature sensor 372. If, for example, the temperature outside the thermally insulated enclosure 352 is too high for cooling of the battery 312 and/or the charge controller 314 to be possible/effective, the relay controller 360 may determine not to operate the relay 320 in the first state even though the battery 312 is in need of cooling.

During winter season, the relay controller 360 may for example be configured to not operate the relay 320 in the first state, such that the thermally insulated enclosure 352 itself may provide a sufficiently high temperature to operate the battery 312 within the certain temperature interval.

To determine whether it is winter or summer season, the relay controller 360 may for example use the temperature sensor 372. In some embodiments, the relay controller 360 may operate the relay 320 based on other conditions than the detected temperature at the power supply (e.g. at the battery 312 and/or the charge controller 314) and at the heat exchange surface 350. The condition may for example be based on a time of day (e.g. such that night-time is assumed to be cooler than day-time, if applicable), time of year (e.g. such that summer-time is assumed to be warmer than winter-time, etc., if applicable) or even on a forecasted weather prognosis.

The relay controller 360 may also operate the relay 320 based on whether e.g. the battery 312 is charging or discharging, for example by operating the relay 320 in the first state when the battery 312 is charging and by operating the relay 320 in the second state when the battery 312 is not charging (and e.g. discharging). Other suitable conditions may also be envisaged.

By using an electrically controllable relay (such as the electrically controllable relay 320), the power supply arrangement may regulate the temperature of the power supply (e.g. the battery and/or the charge controller) during different outside conditions, such as both during summer and winter, and similar.

It may be noted that it is also envisaged that a relay controller as described herein (such as e.g. the relay controller 360) may operate the relay (e.g. to keep a temperature of the power supply to within a certain temperature interval, such as e.g. a comfort temperature interval of a battery in the power supply) without relying on any detected temperature, or at least without relying on any detected temperature at the power supply. The relay controller may for example operate the relay based only on time, forecasted weather, and/or on other conditions such as e.g. whether a battery in the power supply is

charging/discharging (or idle).

With reference to Figure 4, a lighting arrangement including a power supply arrangement is described in the following.

Figure 4 illustrates a lighting arrangement 400 which includes a power supply arrangement (as described in any of the preceding embodiments) and a luminaire 480. The power supply arrangement includes a power supply in the form of a battery 410, an electrically controllable relay 420, a first path 430 arranged between the battery 410 and the relay 420 and a second path 440 arranged between the relay 420 and a heat exchange surface 450. The heat exchange surface is a surface of the luminaire 480. The luminaire 480 includes at least one light source 482 to which power is provided from the battery 410 via for example electrical wires (not shown). The surface of the luminaire 480 may for example be a metal surface, a reflector, a mounting surface for a light source of the luminaire, or similar. If, for example, the surface of the luminaire 480 is close to or in contact with a light source, the heat generated by the light source when it is turned on may be transferred via the paths 430, 440 to the battery 410, if heating of the battery 410 is desirable. This may for example assist in heating the battery 410 faster, if desirable.

The relay 420 may be controlled electrically by a relay control signal provided e.g. on the wire 422, to operate in a first state wherein the first path 430 and the second path 440 are bridged together such that a thermal connection is formed between the battery 410 and the heat exchange surface 450 via the paths 430, 440 and the relay 420. The battery 410 may be housed within a (metallic) battery enclosure 412, and the first path 430 is in one end connected to the battery enclosure 412. Heat may therefore be transferred to/from the battery 410 from/to the first path 430 via the battery enclosure 412.

The relay 420 may also be controlled by the relay control signal to operate in a second state wherein the first path 430 and the second path 440 are disconnected, such that no or little heat transfer is possible between the battery 410 and the heat exchange surface 450 via the first and second paths 430 and 440 respectively and the relay 420.

As illustrated in Figure 4, the lighting arrangement 400 may be mounted in a false ceiling 490. The false ceiling 490 is located below the true ceiling 492, such that a ceiling space 494 is formed between the false ceiling 490 and the true ceiling 492. On the other side of the false ceiling 490, a room space 496 is formed between the false ceiling 490 and e.g. a floor of the room. In some embodiments, and as illustrated in Figure 4, the power supply arrangement and the heat exchange surface 450 are arranged on different sides of the false ceiling 490, such that the power supply arrangement is in the ceiling space 494 and the heat exchange surface 450 faces the room space 496.

The temperature within the ceiling space 494 may, especially during cold climate season, be lower than the room temperature within the room space 492. Reasons for this may for example include that ventilation air is circulated within the ceiling space 494, and/or that the false ceiling 490 itself is what insulates the room from the perhaps cold ceiling 492. Because of this, if the battery 410 is located within the ceiling space 494 (as is often the case due to e.g. aesthetical reasons) the temperature of the battery 410 may be lower than optimal.

With a lighting arrangement 400 including the power supply arrangement as described herein, the relay 420 may be operated in the first state during cold-climate season such that heat may be transferred from a warmer ambient air within the room and at the heat exchange surface 450 to the battery 410 via the first and second paths 430 and 440 respectively, the relay 420 and the battery enclosure 412. Thereby, battery temperature may be maintained at room temperature or within a certain temperature interval such as e.g. the comfort temperature interval of the battery.

During other seasons, such as e.g. during summer, the temperature within the ceiling space 494 may be higher than within the room itself, and the relay 420 may be operated in the first state in order to cool the battery 410 if needed. Likewise, if no cooling or heating of the battery 410 is required, the relay 420 may be operated in the second state such that heat transfer to/from the battery 410 is blocked or at least restricted.

In addition, a relay controller (such as the relay controls 260 and 360 described with reference to Figures 2 and 3 respectively) may be included in the power supply arrangement in the lighting arrangement 400, in order to electrically control the relay 420 based on one or more conditions. Although not shown in Figure 4, it is also envisaged that the power supply arrangement may include also other devices such as a charge controller for charging the battery 410, or e.g. an LED driver for driving the light source 482 of the luminaire 480 from the battery 410. It is envisaged that paths may be provided also for such other devices and connected through the relay 420 (or additional relays not shown in Figure 4) such that also these other devices may be cooled or heated as required. As described with reference to Figure 3, relays with multiple switches and several states of operation may be used to selectively control what power supply device that is connected thermally to one or more heat exchange surfaces at a specific time.

By providing the electrically controllable relay and the first and second paths, heat transfer between a power supply and a heat exchanging surface may be turned off or on as required. The operation of the relay may be manual, or be automated based on e.g. one or more conditions such as temperatures, times, dates, seasons, forecasted weather or operational conditions of the power supply, and similar. This may provide an improved thermal management of power supplies (such as e.g. batteries, charge controllers, LED drivers and similar).

The person skilled in the art realizes that the present disclosure is by no means limited to the embodiments described above. On the contrary, many modifications and variations are possible within the scope of the appended claims.

Although features and elements are described above in particular combinations, each feature or element may be used alone without the other features and elements or in various combinations with or without other features and elements. A feature or element described above with reference to a method may also apply to a device, or vice versa.

Additionally, variations to the disclosed embodiments can be understood and effected by the skilled person in practicing the claimed invention, from a study of the drawings, the disclosure, and the appended claims. In the claims, the word "comprising" does not exclude other elements, and the indefinite article "a" or "an" does not exclude a plurality. The mere fact that certain features are recited in mutually different dependent claims does not indicate that a combination of these features cannot be used to advantage.