Refrigeration appliance with pre-cooling for battery electric vehicles

Abstract

The invention relates to a refrigeration apparatus (20) for use in a battery electric vehicle (1) having a traction battery (4) for driving the electric vehicle and a refrigerated compartment (5) which is cooled by the refrigeration apparatus in use, the refrigeration apparatus comprising: a power supply system (26) for providing power to a refrigeration unit of the refrigeration apparatus, the power supply system comprising a controller (28); wherein the power supply system is configured to be connected to the traction battery and the controller is configured to monitor a charge level of the traction battery; wherein the power supply system is configured to draw power for the refrigeration unit from the traction battery; wherein the controller is configured with a pre-cooling mode to be used during charging of the traction battery from a mains power source; and wherein the pre-cooling mode comprises: authorising the power supply system to supply power to the refrigeration unit from the traction battery in response to the charge level of the traction battery exceeding a predetermined threshold for pre-cooling of the refrigerated compartment of the electric vehicle. A method of operating a refrigeration apparatus is also provided.

Description

TECHNICAL FIELD

[0001] The present invention relates to a refrigeration apparatus for a battery electric vehicle which enters a pre-cooling mode of operation when the battery electric vehicle is charging. BACKGROUND

[0002] In a conventional refrigeration unit for a battery electric vehicle, during "on-road mode" operation, i.e. when the vehicle is in motion, the refrigeration unit is powered by the traction battery of the battery electric vehicle in order to maintain the temperature conditions of the refrigerated compartment.

[0003] However, it is generally desirable to "pre-cool" the refrigerated compartment to a desired temperature before the battery electric vehicle starts moving in order to ensure that temperature sensitive goods are not damaged or spoiled.

[0004] Therefore, in conventional refrigeration units, a specific electrical architecture is provided such that when the battery electric vehicle is parked and charging, the refrigeration unit can be plugged into a mains power source and pre-cool the refrigerated compartment. It is standard practice for the user to plug both the battery electric vehicle and the refrigeration unit into the mains power source for a period of between 12-15 hours, for example, such as overnight. However, in order to pre-cool the refrigerated compartment to the desired temperature, the refrigeration unit only requires power for between 1-4 hours. Therefore, there is a significant amount of additional redundant time in connecting the refrigeration unit to the mains power source.

[0005] It would therefore be advantageous to provide a system in which the refrigeration unit is not connected to a power source for an unnecessary period of time. Furthermore, it would be beneficial to provide a system which does not require connection to a mains power source, but rather can utilise the power stored within the traction battery when the electric vehicle is parked and charging. This would eliminate the need for additional specific electrical architecture required to connect to a mains power source and therefore reduce the complexity and cost of the system. SUMMARY

[0006] Viewed from a first aspect, the present invention provides a refrigeration apparatus for a battery electric vehicle, the battery electric vehicle having a traction battery for driving the electric vehicle and a refrigerated compartment which in use is cooled by the refrigeration apparatus, the refrigeration apparatus comprising:

[0007] a power supply system for providing power to a refrigeration unit of the refrigeration apparatus, the power supply system comprising a controller;

[0008] wherein the power supply system is configured to be connected to the traction battery and the controller is configured to monitor a charge level of the traction battery;

[0009] wherein the power supply system is configured to draw power for the refrigeration unit from the traction battery;

[0010] wherein the controller is configured with a pre-cooling mode to be used during charging of the traction battery from a mains power source; and

[0011] wherein the pre-cooling mode comprises authorising the power supply system to supply power from the traction battery to the refrigeration unit in response to a charge level of the traction battery exceeding a predetermined threshold for pre-cooling of the refrigerated compartment of the electric vehicle.

[0012] Thus, the provided refrigeration apparatus is able to respond to detecting that the electric vehicle in which it is installed is being charged and / or is in an appropriate state of charge by drawing power from the traction battery to power the refrigeration unit to initiate pre-cooling of the refrigerated compartment. As the refrigeration unit does not need to be directly connected to a dedicated mains power source, the system reduces the complexity and cost of the electrical architecture. Furthermore, as the power supply system is only authorised to supply power from the traction battery to the refrigeration unit when the traction battery has a predetermined charge, this allows the refrigeration unit to only use the energy required to be used to pre-cool the refrigerated compartment to the desired temperature, thus minimising energy consumption. This can typically be done with minimal or zero impact on the operation of the vehicle. Many users will plug such a vehicle in during a 12 to 15 hour period of disuse, such as overnight, during which only a portion of the traction battery needs to be charged. The pre-cooling for the refrigerated compartment can take only 1 to 4 hours, and the inventors have realised that this is typically the time available when the vehicle is plugged in and allows power to be drawn from the traction battery during one or more interruptions in its charging, thus providing a "smart standby" pre-cooling capability.

[0013] The pre-cooling mode can further comprise interrupting charging of the traction battery in response to the charge level exceeding the predetermined threshold; and authorising the power supply system to supply power from the traction battery to the refrigeration unit for pre-cooling of the refrigerated compartment of the electric vehicle when charging of the traction battery has been interrupted.

[0014] The pre-cooling mode can further comprise determining a pre-cooling requirement of the refrigerated compartment of the electric vehicle, and pre-cooling the refrigerated compartment in accordance with the pre-cooling requirement. The pre-cooling requirement can be a difference between a desired temperature and a measured temperature of the refrigerated compartment. The pre-cooling requirement can be a predetermined amount of pre-cooling in order to maintain temperature conditions of the refrigerated compartment.

[0015] Thus, during the pre-cooling mode, the refrigeration apparatus can only pre-cool the refrigerated compartment in accordance with the temperature requirement of the refrigerated compartment. If it is determined that the refrigerated compartment is at the desired temperature, the power supply system can not draw power from the traction battery, even if the controller has authorised this.

[0016] The power supply system can be arranged to draw power for the refrigeration unit only from the traction battery. Thus, the power supply system can be arranged to not be able to draw power for the refrigeration unit from the mains power source. Removing the specific electrical architecture of conventional systems designed to allow plugging in of the refrigeration unit to the mains power source, and using the existing electrical architecture through which power has been supplied to the refrigeration unit from the traction battery in "run mode", to exclusively provide power to the refrigeration unit for pre-cooling, reduces the cost and electrical complexity of the system. For example, the proposed system can have fewer transformers and fewer power electronics components than prior art arrangements.

[0017] The controller can be further configured with a road operating mode to be used during a driving period of the electric vehicle, wherein the road mode comprises drawing power from the traction battery using the power supply system for supply to the refrigeration unit. The road mode can comprise continuously drawing power from the traction battery using the power supply system for supply to the refrigeration unit. Thus, the electrical infrastructure connecting the power supply system to the traction battery can be used for different operating modes; and the refrigeration unit can be continuously operated to maintain the temperature of the refrigerated compartment while the battery electric vehicle is driving.

[0018] The electric vehicle can be a commercial vehicle for transporting goods, for example a light commercial vehicle (LCV).

[0019] The traction battery can be used to power the electric vehicle, which can be done in the road mode and / or can be done while supplying power to the refrigeration unit in the road mode. The traction battery can be configured to provide power to the vehicle for a sustained period of time, such as for a period of up to 5 or 10 hours, or in the range of 50 to 300 miles, including cooling of the refrigerated compartment and power to drive the vehicle. The traction battery can take several hours to charge, for example a full night charge taking at least 5 hours to charge the battery, for example a charging period of 5 to 10 hours.

[0020] The mains power source can be a standard electrical socket, for example a mains voltage single phase supply, or the mains power source can be a dedicated charging station for battery electric vehicles. The traction battery can comprise an AC-DC electrical converter. Vehicle manufacturers can equip the traction battery with various power sources and / or charging systems. The current proposal has the advantage that the refrigeration unit can be provided with power for pre-cooling in the same way, regardless of the charging mechanism of the traction battery.

[0021] The electric vehicle can comprise an electric vehicle controller which can determine the State of Charge (SoC) of the traction battery. The electric vehicle controller can be a standard fit by the vehicle manufacturer, or can be added to the electric vehicle as part of adapting it for refrigerated transport.

[0022] The controller can monitor the charge level directly. Direct monitoring of the charge level provides a more robust system as it does not rely on any other electronic components.

[0023] The controller can be connected to the electric vehicle controller by a controller area network (CAN) bus. This type of bus is commonly used in association with vehicle systems, and advantageously, the controller for the power supply system can utilise the pre-existing bus connection of the electric vehicle, again allowing the refrigeration unit to be easily integrated with a range of electric vehicle designs from different manufacturers without requiring major modification to the OEM traction battery system.

[0024] The controller can be configured to monitor the charge level by obtaining the charge level from the electric vehicle controller.

[0025] Alternatively, the controller can be configured to receive authorisation from the electric vehicle controller to supply power from the traction battery to the refrigeration unit for pre-cooling of the refrigerated compartment of the electric vehicle.

[0026] The controller can be configured to instruct the electric vehicle controller to interrupt charging of the traction battery, for example based on logic relating to the charge level of the battery and / or the temperature of the refrigerated compartment.

[0027] The electric vehicle controller can already be configured to measure and relay the charge level, so obtaining the charge level from the electric vehicle controller and interrupting charging of the vehicle via the electric vehicle controller can use infrastructure already present in the battery electric vehicle, reducing installation costs.

[0028] The controller can be configured to interrupt charging of the traction battery for one or more pre-cooling periods in response to the charge level exceeding a relatively low threshold, such as 50%, which can then allow pre-cooling to take place over an extended period of time during intermittent interruptions, with the remaining 50% of charging occurring. In one example, the battery charge can be allowed to discharge by a set amount, such as 10%, during pre-cooling, and then can be recharged by a higher set amount, such as 20%, between pre-cooling uses, thereby progressively increasing the battery charge level with intermittent pre-cooling cycles. When the charge level reaches a relatively high level, such as 90%, then pre-cooling can be carried out as set out below. The remaining 10% of charging can occur after pre-cooling is complete.

[0029] The controller can be configured to interrupt charging of the traction battery in response to the charge level exceeding a relatively high threshold, such as 90%, for one or more pre-cooling periods, which then allow pre-cooling to take place in the time leading up to the end of the charging cycle. This can be a period of time shortly before the expected time at which the vehicle will be used for refrigerated transport. In this case, pre-cooling can take place during intermittent interruptions, with the battery charge topped up to at most 90% between each pre-cooling period. The remaining 10% of charging can take place after pre-cooling is complete.

[0030] The controller can be configured to interrupt charging of the traction battery in response to the charge level exceeding a predetermined threshold and / or a certain period of time, for example the time elapsed since a previous pre-cooling operating mode. The controller can also be configured to allow manual initiation of the pre-cooling mode.

[0031] The controller can be configured to interrupt charging of the traction battery and cause the power supply system to start drawing power from the traction battery at periodic predetermined time intervals.

[0032] The option of providing the user with precise control over the predetermined charge level threshold and / or time, when the compartment is pre-cooled, helps to minimise the energy consumption of the system.

[0033] The controller can be configured to monitor the charge level of the traction battery while charging of the traction battery has been interrupted.

[0034] As mentioned above, the predetermined threshold can be an upper threshold, and the controller can be configured to resume charging of the traction battery and cause the power supply system to stop drawing power from the traction battery in response to the charge level falling below a lower threshold, for example in steps of 10% or 20%. Tracking the charge level of the traction battery while the power supply system is drawing power for pre-cooling and then stopping the drawing of power when the charge level falls below the lower threshold provides an intelligent system which can extract electrical energy from the traction battery without compromising the charge stored in the traction battery, i.e. only when the traction battery can afford to lose it. These thresholds can be precisely controlled by the user.

[0035] The controller can be configured to resume charging of the traction battery and cause the power supply system to stop drawing power from the traction battery in response to the charge level falling a set level below the charge level at which charging was interrupted. For example, this can be 10% below the level at which charging was interrupted, so if the charge level falls below 80% when charging was interrupted at 90%, this would involve resuming charging.

[0036] The controller can be configured to interrupt charging of the traction battery and cause the power supply system to start drawing power from the traction battery in response to the state of charge first exceeding the upper threshold, and to resume charging of the traction battery and cause the power supply system to stop drawing power from the traction battery in response to the state of charge first falling below the lower threshold.

[0037] The upper threshold can be a plurality of upper thresholds, and the lower threshold can be a plurality of lower thresholds, wherein the controller is configured to cause the power supply system to start and stop drawing power from the traction battery in a sequential, step-wise manner.

[0038] Depending on the type of battery electric vehicle, and a variety of other factors, it can be desirable for the system to pre-cool the refrigerated compartment by drawing power from the traction battery within a predetermined range, for example, starting to draw power when the traction battery reaches 90% charge, stopping to draw power when the traction battery falls to 80% charge, starting to draw power when the traction battery reaches 90% charge again, and so on. In this way, the traction battery can be quickly charged to 90% charge, and then the remaining charging time used for the pre-cooling operation of the compartment. For some battery systems, there can be a peak efficiency range for the operation of the refrigeration unit, and the system can therefore seek to use this range during the pre-cooling mode.

[0039] Alternatively, the system can draw power from the traction battery at predetermined stages. For example, this can include starting to draw power when the traction battery reaches 50% charge, stopping to draw power when the traction battery falls to 40% charge, starting to draw power when the traction battery reaches 60% charge, stopping to draw power when the battery falls to 50% charge, and so on. In this way, the charge level of the traction battery will increase slowly, while power will be drawn periodically to run the pre-cooling operation. As mentioned above, depending on the user requirements and the type of battery electric vehicle, either option can be preferred for cost, power consumption, and power efficiency considerations.

[0040] The refrigeration apparatus can comprise a refrigeration unit.

[0041] The refrigeration unit can comprise a refrigeration circuit having suitable means for providing cooling to the refrigerated compartment. For example, the refrigeration unit can comprise a compression device, a heat rejection heat exchanger, a heat absorption heat exchanger, and an expansion device.

[0042] The power supply system can be operably coupled to an electric motor of the compression device.

[0043] Viewed from a second aspect, the present application provides a battery electric vehicle, the battery electric vehicle comprising:

[0044] a traction battery for providing motive power to the vehicle;

[0045] a refrigerated compartment; and

[0046] The refrigeration appliance as discussed above in the first aspect and optionally including any / all of the other features discussed above.

[0047] Viewed from a third aspect, the present application provides a method of operating a refrigeration appliance for cooling a refrigerated compartment of a battery electric vehicle having a traction battery for driving the battery electric vehicle, the method comprising: determining, by a controller of a power supply system of the refrigeration appliance, when the traction battery of the battery electric vehicle is being charged from a mains power source; and running a pre-cooling operating mode comprising: monitoring, by the controller, a charge level of the traction battery; authorising, by the controller, the power supply system to supply power from the traction battery to a refrigeration unit in response to the charge level exceeding a predetermined threshold; drawing power from the traction battery via the power supply system; and supplying power to a refrigeration unit of the refrigeration appliance via the power supply system for pre-cooling the refrigerated compartment.

[0048] The refrigeration appliance can be as discussed above in the first aspect and optionally can include any / all of the other features discussed above.

[0049] The step of authorising the power supply system can comprise:

[0050] interrupting, by the controller, charging of the traction battery in response to the charge level exceeding the predetermined threshold; and

[0051] authorising the power supply system to supply power from the traction battery to the refrigeration unit when charging of the traction battery has been interrupted.

[0052] The running of the pre-cooling operating mode can further comprise:

[0053] determining a pre-cooling requirement of the refrigerated compartment of the battery electric vehicle; and the step of supplying power via the power supply can comprise supplying the power to the refrigeration unit of the refrigeration appliance in accordance with the pre-cooling requirement. The pre-cooling requirement can be a difference between a desired temperature and a measured temperature of the refrigerated compartment. The pre-cooling requirement can be a predetermined amount of pre-cooling in order to maintain temperature conditions of the refrigerated compartment.

[0054] Thus, during the pre-cooling mode, the refrigeration appliance can pre-cool the refrigerated compartment only in accordance with temperature requirements of the refrigerated compartment. If it is determined that the refrigerated compartment is at a desired temperature, the power supply system can not draw power from the traction battery even though the controller has authorised this.

[0055] The pre-cooling operating mode can comprise drawing power exclusively from the traction battery for supply to the refrigeration unit of the refrigeration appliance.

[0056] The method of operating a refrigeration appliance for cooling a refrigerated compartment of a battery electric vehicle can further comprise:

[0057] determining, by a controller of a power system of the refrigeration appliance, when the electric vehicle is travelling; and operating a road operating mode, which includes:

[0058] drawing power from the traction battery via the power system;

[0059] and supplying power to a refrigeration unit of the refrigeration appliance via the power system for cooling the refrigerated compartment.

[0060] The road operating mode can include drawing power from the traction battery and continuously supplying power to the refrigeration unit.

[0061] Determining when the electric vehicle is travelling can include determining whether the traction battery is providing power to the electric vehicle.

[0062] Monitoring the charge level of the traction battery can be performed directly by the controller.

[0063] Monitoring the charge level of the traction battery can include obtaining, by the controller, the charge level from an electric vehicle controller.

[0064] The step of authorising the power system can include:

[0065] Receiving, by the controller, authorisation from the electric vehicle controller of the power system to supply power from the traction battery to the refrigeration unit.

[0066] Interrupting charging of the traction battery can include instructing, by the controller, the electric vehicle controller to interrupt charging of the traction battery charge.

[0067] Authorising the power system to supply power from the traction battery to the refrigeration unit in response to the charge level exceeding a predetermined threshold can include authorising the power system to supply power from the traction battery to the refrigeration unit in response to the charge level exceeding 50%.

[0068] Authorising the power system to supply power from the traction battery to the refrigeration unit in response to the charge level exceeding a predetermined threshold can include authorising the power system to supply power from the traction battery to the refrigeration unit in response to the charge level exceeding 90%.

[0069] The step of authorising the power system to supply power from the traction battery to the refrigeration unit can include authorising the power system to supply power from the traction battery to the refrigeration unit in response to the charge level exceeding a predetermined threshold and / or a period of time (e.g. time elapsed since a previous pre-cooling operating mode).

[0070] The step of authorising the power system to supply power from the traction battery to the refrigeration unit can include authorising the power system to supply power from the traction battery to the refrigeration unit and causing the power system to start drawing power from the traction battery at periodic predetermined time intervals.

[0071] The pre-cooling operational mode can comprise monitoring the charge level of the traction battery while charging of the traction battery has been interrupted.

[0072] The controller can be configured to cause the power supply system to stop drawing power from the traction battery in response to the charge level falling below 80%. The controller can be configured to resume charging of the traction battery if charging of the traction battery has previously been interrupted.

[0073] The pre-cooling operational mode can comprise:

[0074] interrupting, by the controller, charging of the traction battery and starting drawing power from the traction battery via the power supply system in response to the charge level first exceeding an upper threshold; and

[0075] resuming, by the controller, charging of the traction battery and stopping drawing power from the traction battery via the power supply system in response to the charge level first falling below a lower threshold.

[0076] The upper threshold can be a plurality of upper thresholds, and the lower threshold can be a plurality of lower thresholds, wherein the pre-cooling operational mode can comprise causing the power supply system to start and stop drawing power from the traction battery and supplying power to the refrigeration unit of the refrigeration appliance in a sequential, step-wise manner.

[0077] The step of supplying power to the refrigeration unit of the refrigeration appliance via the power supply system for pre-cooling the refrigerated compartment can comprise supplying power to an electric motor of a compression device of the refrigeration unit.

[0078] Viewed from a fourth aspect, the present invention provides a computer-readable storage medium comprising instructions which, when executed by a controller of a power supply system of a refrigeration appliance for cooling a refrigerated compartment of an electric battery vehicle having a traction battery for driving the electric battery vehicle, cause a processor to perform a method of operating the refrigeration appliance, the method comprising: determining, by the controller, when the traction battery of the electric battery vehicle is being charged from a mains power source; and running a pre-cooling operational mode comprising: monitoring, by the controller, a charge level of the traction battery; authorizing, by the controller, the power supply system to supply power from the traction battery to the refrigeration unit in response to the charge level exceeding a predetermined threshold; drawing power from the traction battery via the power supply system; and supplying power to the refrigeration unit of the refrigeration appliance via the power supply system for pre-cooling the refrigerated compartment. The method can be as discussed above in relation to the third aspect and optional features thereof. BRIEF DESCRIPTION OF DRAWINGS

[0079] Preferred embodiments of the present disclosure will now be described in more detail, by way of example only, with reference to the attached drawings in which:

[0080] Figure 1 A battery electric vehicle is shown having a refrigeration appliance of the prior art having a direct connection to mains power;

[0081] Figure 2 A battery electric vehicle is shown with a refrigeration appliance adapted to avoid a direct mains power connection;

[0082] Figure 3 A method is shown of operating a refrigeration appliance to pre-cool a refrigerated compartment of a battery electric vehicle;

[0083] Figure 4 A state of charge (SOC) of a traction battery of a battery electric vehicle is shown when the refrigeration appliance is operated according to Figure 3

[0084] Figure 5 A further method is shown of operating a refrigeration appliance to pre-cool a refrigerated compartment of a battery electric vehicle; and

[0085] Figure 6 A state of charge (SOC) of a traction battery of a battery electric vehicle is shown when the refrigeration appliance is operated according to Figure 5 DETAILED DESCRIPTION

[0086] Figure 1 A battery electric vehicle 1 is shown with a refrigeration appliance 2 of the prior art.

[0087] The electric vehicle 1 is a conventional battery electric vehicle comprising a traction battery 4 for providing power to the electric vehicle 1 during "on-road mode" operation, i.e. when the vehicle 1 is travelling.

[0088] The traction battery 4 is configured to provide power to the electric vehicle 1 over a sustained period of travel, for example a period of up to 5 to 10 hours, or a distance range of 50 to 300 miles. The traction battery 4 is charged by connection to a mains power source.

[0089] The traction battery 4 comprises a battery power supply 8, for example an AC-DC power converter or transformer, for converting power received from a mains power source, which can be a standard electrical socket, such as a mains voltage single phase supply, or a dedicated charging station for the electric vehicle 1, to suitably charge the traction battery 4.

[0090] The battery electric vehicle 1 comprises a refrigerated compartment 5. The refrigeration appliance 2 comprises a refrigeration unit 3 which cools the refrigerated compartment 5.

[0091] During "on-road mode" operation, i.e. when the traction battery 4 is providing power to the electric vehicle, the traction battery 4 also provides power to the refrigeration appliance 2 through a power supply 6, enabling the refrigeration unit to maintain temperature conditions of the refrigerated compartment 5.

[0092] ​​The refrigeration appliance 2 is configured with a "pre-cooling" operating mode, in which the refrigerated compartment 5 is "pre-cooled" to a desired temperature before the battery electric vehicle 1 starts driving. The pre-cooling can ensure that temperature sensitive goods to be placed in the refrigerated compartment 5 by 1 are not damaged or spoiled.

[0093] The refrigeration appliance 2 therefore comprises a pre-cooling power supply 7, so that the refrigeration appliance 2 can be plugged into a mains power source and pre-cool the refrigerated compartment 5 while the battery electric vehicle 1 is parked and charging. The pre-cooling power supply 7 comprises an AC-AC power transformer or the like, and other typical electrical components, to be suitable for any type of mains power source.

[0094] The refrigeration appliance 2 therefore comprises a pre-cooling power supply 7, so that the refrigeration appliance 2 can be plugged into a mains power source and pre-cool the refrigerated compartment 5 while the battery electric vehicle 1 is parked and charging. The pre-cooling power supply 7 comprises an AC-AC power transformer or the like, and other typical electrical components, to be suitable for any type of mains power source.

[0095] However, to pre-cool the refrigerated compartment 5 to a desired temperature, the refrigeration unit 3 only requires 1-4 hours of power. There is therefore a significant amount of redundant time in case the refrigeration unit 3 is connected to a mains power source.

[0096] Figure 2 A battery electric vehicle 1 is shown with a refrigeration appliance 20 according to the present application.

[0097] The battery electric vehicle 1 operates in a similar manner as known battery electric vehicles as described above, but with the following differences. Identical elements are labeled with corresponding reference numerals.

[0098] The battery electric vehicle 1 comprises a vehicle controller 9. The vehicle controller 9 is configured to operate the electric vehicle 1 during normal driving ("on-road mode"). This includes determining the State of Charge (SoC) of the traction battery 4. This information is typically presented to the driver of the battery electric vehicle 1 on the dashboard or the like of the electric vehicle 1. The electric vehicle controller 9 can be a standard fitment according to the vehicle manufacturer, or can alternatively be added to the electric vehicle 1 as part of adapting it to the refrigeration appliance 20.

[0099] The refrigeration appliance 20 comprises a power supply system 26 for providing power to the refrigeration unit 3 of the refrigeration appliance 20.

[0100] The power supply system 26 comprises a controller 28 configured to operate the power supply system 26 to provide power to the refrigeration unit 3.

[0101] During "on-road mode", the controller 28 is configured to operate the power supply system 26 to continuously draw power from the traction battery 4 to operate the refrigeration unit 3 to maintain the temperature conditions of the refrigerated compartment 5.

[0102] The controller 28 is configured to communicate with the electric vehicle controller 9 by means of a connection via a controller area network (CAN) bus 10. This type of bus is commonly used in association with vehicle systems, and advantageously, Figure 2 The controller 28 of the power supply system 26 can make use of pre-existing bus connections of the electric vehicle 1.

[0103] With this arrangement, the controller 28 is configured to acquire operational information about the electric vehicle 1, for example the current SOC of the traction battery 4, but the controller 28 can acquire this operational information directly or by other means.

[0104] The controller 28 is further configured with a pre-cooling mode to be used during charging of the traction battery 4. During the pre-cooling mode, the controller 28 is configured to interrupt charging of the traction battery 4 in response to determining that the SOC of the traction battery 4 exceeds a predetermined threshold, in order to operate the refrigeration unit 3 to pre-cool the refrigerated compartment 5.

[0105] The described configuration of the refrigeration appliance 20 is capable of operating in a pre-cooling mode, in which the power supply system 26 is arranged to supply power to the refrigeration unit 3 from the traction battery 4, rather than from a mains power source. Advantageously, the refrigeration appliance 20 therefore does not require a dedicated pre-cooling power supply 7. The power supply system 26 draws power from the traction battery 4 through an existing electrical connection already present in the battery electric vehicle 1, which is used to continuously supply power to the refrigeration unit 3 during "on-road" operation.

[0106] A method of operating the refrigeration appliance 20 to cool the refrigerated compartment 5 of the battery electric vehicle 1 will now be described.

[0107] Firstly, the controller 28 determines whether the battery electric vehicle 1 is driving, i.e. whether the vehicle is in "on-road" mode, or whether the battery electric vehicle 1 is stopped and charging.

[0108] In response to determining that the traction battery 4 is charging, the controller 28 initiates a pre-cooling mode of operation.

[0109] In the pre-cooling mode of operation, the controller 28 monitors the charge level (SOC) of the traction battery 4. This can be achieved by acquiring operational information about the battery electric vehicle 1 from the vehicle controller 9 via the CAN bus 10.

[0110] If the controller 28 detects that the charge level of the traction battery 4 exceeds a certain predetermined threshold, the controller 28 authorises the power supply system to supply power to the refrigeration unit from the traction battery. This can include instructing the vehicle controller 9 to stop charging the traction battery 4.

[0111] Next or simultaneously, the power supply system 26 starts to draw power from the traction battery 4 and supplies said power to the refrigeration unit 3 to pre-cool the refrigerated compartment 5.

[0112] Advantageously, the controller 28 is configured to monitor the charge level of the traction battery 4 while the power supply system 26 is drawing power from the traction battery 4. Thus, the controller 28 can be configured to resume charging of the traction battery 4 (e.g. by instructing the vehicle controller 9 to resume charging) and instruct the power supply system 26 to stop drawing power from the traction battery 4 in response to the charge level of the battery 4 falling below a second predetermined threshold, which is at a lower value than the first threshold.

[0113] The steps of interrupting charging of the traction battery 4, starting to draw power from the traction battery 4, resuming charging of the traction battery, and stopping drawing power from the traction battery 4 can be sequentially repeated while in the pre-cooling mode. The sequential steps can be implemented in two possible ways, as shown in the figures.

[0114] In a first example, as shown in Figure 3 and 4 , the controller 28 is configured to evaluate the monitored charge level (SOC) of the traction battery 4 against fixed upper and lower thresholds throughout the duration of the pre-cooling mode.

[0115] If the SOC of the traction battery exceeds a predetermined upper threshold (e.g. 90%), the controller 28 authorizes the power supply system 26 to start drawing power from the traction battery 4 to supply to the refrigeration unit 3 to pre-cool the refrigerated compartment 5. The controller 28 can also instruct the vehicle controller 9 to interrupt charging of the traction battery 4.

[0116] As shown in Figure 4 , the power supply system 26 supplies power to the refrigeration unit 3 as needed, depending on the pre-cooling requirements of the refrigerated compartment 5 of the electric vehicle 1. If the refrigeration device 20 determines that the refrigerated compartment 5 is already at the desired pre-cooling temperature, the power supply system 26 will not draw power from the traction battery 4, even if it has been authorized to do so. If the refrigeration device 20 determines that the refrigerated compartment 5 is not at the desired pre-cooling temperature, but the power supply system 26 has not been authorized to supply power to the refrigeration unit 3 (because the SOC is below a predetermined threshold or for other reasons), the power supply system 26 will not draw power from the traction battery 4.

[0117] While the power supply system 26 is supplying power to the refrigeration unit 3, the controller 28 monitors the SOC of the traction battery 4. Once the SOC falls below a predetermined lower threshold (e.g. 80%), the controller 28 instructs the power supply system 26 to stop drawing power from the traction battery 4. The controller 28 can also instruct the vehicle controller 9 to resume charging of the traction battery 4.

[0118] These steps are then repeated periodically during the charging period of the traction battery 4, with the refrigeration unit 3 requiring less power to be drawn by the power system 26 as the refrigerated compartment 5 approaches its desired temperature.

[0119] In a second example, as shown in Figure 5 and 6 The controller 28 is configured to evaluate the monitored state of charge (SOC) of the traction battery 4 against a series of successively increasing charge thresholds during the pre-cooling mode period.

[0120] For example, as can be seen from Figure 6 When the SOC of the traction battery 4 first exceeds a first predetermined upper threshold (e.g. 50%), the controller 28 instructs the vehicle controller 9 to interrupt charging of the traction battery 4, and the power system 26 begins to draw power from the traction battery 4 to supply it to the refrigeration unit 3 to pre-cool the refrigerated compartment 5.

[0121] The controller 28 monitors the SOC of the traction battery 4 whilst the power system 26 is supplying power to the refrigeration unit 3. Once the SOC first falls below a first predetermined lower threshold (e.g. 40%), the controller 28 instructs the vehicle controller 9 to resume charging of the traction battery 4, and the power system 26 ceases to draw power from the traction battery 4.

[0122] When the SOC of the traction battery 4 first exceeds a second predetermined upper threshold (e.g. 60%), the controller 28 again instructs the vehicle controller 9 to interrupt charging of the traction battery 4, and the power system 26 again begins to draw power from the traction battery 4 to supply it to the refrigeration unit 3 to pre-cool the refrigerated compartment 5.

[0123] When the SOC first falls below a second predetermined lower threshold (e.g. 50%), the controller 28 instructs the vehicle controller 9 to resume charging of the traction battery 4, and the power system 26 ceases to draw power from the traction battery 4.

[0124] The controller 28 is therefore configured to cause the power system to begin and cease drawing power from the vehicle battery 4 in a sequential, step-wise manner. The pre-cooling of the refrigerated compartment 5 therefore also occurs in a sequential, step-wise manner.

[0125] In an alternative arrangement, the controller 28 can be configured to monitor the temperature within the refrigerated compartment 5, or to measure the length of time for which the power system 26 has been drawing power from the traction battery 4. Once the monitored temperature has reached the desired temperature, or a predetermined period of time has elapsed, the controller 28 is configured to resume charging of the traction battery 4 (e.g. by instructing the vehicle controller 9 to resume charging) and to cause the power system 26 to cease drawing power from the traction battery 4.

[0126] Furthermore, the controller 28 can be configured to start and stop the pre-cooling cycle depending on a combination of various factors, including for example the temperature of the refrigerated compartment 5 and the SOC of the traction battery 4.

[0127] The controller 28 can be configured to implement any or all of the control methods discussed above, deciding which control method to implement based on the specifications of the battery electric vehicle 1, the refrigerated compartment 5 or the traction battery 4, for reasons such as improving energy efficiency or faster battery charging.

Claims

1. A refrigeration device for use in a battery electric vehicle having a traction battery for driving the electric vehicle and a refrigerated compartment cooled in use by the refrigeration device, the refrigeration device comprising: a power supply system for providing power to a refrigeration unit of the refrigeration equipment, the power supply system comprising a controller; wherein the power system is configured to be connected to the traction battery; wherein the power system is configured to draw power for the refrigeration unit from the traction battery; The controller is configured to: determining when a traction battery of the electric vehicle is connected to and charged from a mains power source; and In response to detecting that the traction battery is being charged from a mains power source, executing a pre-cooling operating mode comprising: monitoring a charge level of the traction battery; as well as In response to the charge level of the traction battery exceeding a predetermined threshold, the power system is authorized to supply power from the traction battery to the refrigeration unit for pre-cooling of a refrigerated compartment of the electric vehicle.

2. The refrigeration equipment according to claim 1, characterized in that The power system can be arranged to draw power for the refrigeration unit only from the traction battery.

3. The refrigeration equipment according to claim 1 or claim 2, characterized in that: The pre-cooling mode further includes interrupting charging of the traction battery in response to the charge level exceeding a predetermined threshold; and authorizing the power supply system to supply power from the traction battery to the refrigeration unit for pre-cooling the refrigerated compartment of the electric vehicle when charging of the traction battery has been interrupted.

4. The refrigeration equipment according to claim 3, characterized in that The controller is configured to monitor a charge level of the traction battery when charging of the traction battery has been interrupted.

5. The refrigeration equipment according to claim 1 or claim 2, characterized in that: The controller can be further configured with a road operating mode to be used during driving periods of the electric vehicle, wherein the road operating mode includes using the power system to draw power from the traction battery to supply the refrigeration unit.

6. The refrigeration equipment according to claim 1 or claim 2, characterized in that: The controller monitors the charge level directly; or wherein the controller is configured to monitor the charge level by obtaining the charge level from an electric vehicle controller.

7. The refrigeration equipment according to claim 1 or claim 2, characterized in that: The predetermined threshold may be an upper threshold, and the controller is configured to resume charging the traction battery and stop the power supply system from drawing power from the traction battery in response to the charge level falling below a lower threshold.

8. The refrigeration equipment according to claim 1 or claim 2, characterized in that: The controller can be configured to interrupt charging of the traction battery and cause the power system to begin drawing power from the traction battery in response to the charge level first exceeding an upper threshold, and to resume charging of the traction battery and cause the power system to stop drawing power from the traction battery in response to the charge level first falling below a lower threshold.

9. The refrigeration equipment according to claim 8, characterized in that The upper threshold can be a plurality of upper thresholds, and the lower threshold can be a plurality of lower thresholds, wherein the controller is configured to cause the power system to start and stop drawing power from the traction battery in a sequential, step-by-step manner.

10. A method of operating a refrigeration appliance for cooling a refrigerated compartment of a battery electric vehicle having a traction battery for driving the electric vehicle, the method comprising: determining, by a controller of the power system of the refrigeration appliance, when a traction battery of the electric vehicle is connected to and charged from a mains power source; as well as In response to detecting that the traction battery is being charged from a mains power source, executing a pre-cooling operating mode comprising: monitoring, by the controller, a charge level of the traction battery; in response to the charge level exceeding a predetermined threshold, authorizing, by the controller, the power system to supply power from the traction battery to a refrigeration unit of the refrigeration equipment; drawing power from the traction battery via the power system; and Power is supplied to the refrigeration unit via the power supply system for pre-cooling the refrigerated compartment.

11. The method for operating a refrigeration device according to claim 10, characterized in that: The steps of authorizing the power system include: interrupting, by the controller, charging of the traction battery in response to the charge level exceeding a predetermined threshold; and The power system is authorized to supply power from the traction battery to the refrigeration unit when charging of the traction battery has been interrupted.

12. The method for operating a refrigeration device according to claim 10 or claim 11, characterized in that: Drawing power via the power system includes drawing power via the power system only from the traction battery.

13. The method for operating a refrigeration device according to claim 10 or claim 11, characterized in that: The method further comprises: determining, by a controller of a power system of the refrigeration equipment, when the electric vehicle is traveling; and operating a road operation mode, which includes: drawing power from the traction battery via the power system; and Power is supplied to a refrigeration unit of the refrigeration appliance via the power supply system for cooling the refrigerated compartment.

14. The method for operating a refrigeration device according to claim 10 or claim 11, characterized in that: The pre-cooling operation mode includes: in response to the charge level exceeding an upper threshold for the first time, interrupting, by the controller, charging of the traction battery and commencing to draw power from the traction battery via the power system; and In response to the charge level falling below a lower threshold for the first time, charging of the traction battery is resumed by the controller and power is ceased to be drawn from the traction battery via the power system.

15. The method for operating a refrigeration device according to claim 14, characterized in that: The upper threshold can be a plurality of upper thresholds, and the lower threshold can be a plurality of lower thresholds, wherein the pre-cooling operating mode can include causing the power system to start and stop drawing power from the traction battery and supplying power to the refrigeration unit of the refrigeration device in a sequential, step-by-step manner.

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