Mobile power

Abstract

A mobile power unit weighs less than 3500 kg and comprises an accumulator with a total capacity of at least 40 kWh, the accumulator comprising at least one repurposed battery pack from an electric vehicle, a removable battery module, a dock arranged to releasably receive the removable battery module and to allow the accumulator to charge the battery module; an output socket arranged to provide power from the unit to a device plugged into the socket in use; and a control system arranged to interface with an original battery management system of the repurposed battery pack and to control power flows between the accumulator, socket, and dock. A kit of parts comprising such a mobile power unit and a plurality of dockable battery modules is also provided.

Description

[0001] MOBILE POWER

[0002] The present invention relates to a mobile power unit, which may be moved in a van or on a trailer, and which may be used to provide off-grid power and / or on-grid flexible energy management. The mobile power unit comprises a main accumulator suitable for use for relatively high-voltage or high-power applications and also one or more docked battery modules which may be removed and used separately for lower-power applications, and then re-docked and re-charged.

[0003] As the grid is decarbonised, the supply of energy becomes more volatile and more sensitive to imbalance between supply and demand. Consequently, the grid needs greater flexibility to balance the electricity network and avoid capacity constraints. Intelligent ways to store energy off-peak and dispatch power when and where it is needed at peak times are therefore required. More efficient ways to predict and smooth out demand are also needed, for example through load shifting and balancing at a local level to support the grid. In addition, flexible off-grid power supplies are becoming increasingly important in many sectors.

[0004] Energy storage can provide a solution for both issues, but available systems are currently not sufficiently attractive to consumers for widespread uptake. Currently-available energy storage systems for commercial applications can be divided into two categories:

[0005] 1. On-grid systems are connected to the electricity network and use an accumulator to charge and discharge energy on-demand. These systems can be used for energy arbitrage, buying cheap and selling back at higher prices; for emergency power for utilities and distribution network operators; for back-up power for businesses such as data centres and supermarkets; and / or for buffer storage for installations that require high power like electric vehicle (EV) fast charging stations; and

[0006] 2. Off-grid systems operate islanded from the electricity network and are used in applications like remote power and microgrids, as well as for emergency power when the grid is unavailable.

[0007] On-grid energy storage solutions are often designed to be bespoke to specific customer requirements onsite, and can be time-consuming and expensive to install, and rendered obsolete by business changes or moves. Current off-grid solutions have limited features and merely operate as an alternative to a diesel generator.

[0008] According to a first aspect, there is provided a mobile power unit weighing less than 3500 kg and comprising: an accumulator with a total capacity of at least 40 kWh, the accumulator comprising at least one repurposed battery pack from an electric vehicle, the repurposed battery pack comprising its original battery management system; a removable battery module; a dock arranged to releasably receive the removable battery module, the dock being electrically connected to the accumulator such that the accumulator can be used to charge a docked removable battery module; an output socket arranged to provide power from at least one of the accumulator and a docked removable battery module to a device plugged into the socket in use; and a control system arranged to interface with the at least one original battery management system and to control power flows between the accumulator, socket, and dock Such a mobile energy storage device may be used both off-grid and on-grid, providing a highly versatile energy storage configuration that can be deployed in flexible, mobile, and dynamic ways for a wide variety of applications without changes to the apparatus. The mobile power unit therefore provides improved flexibility and efficiencies - with on-grid use offering a benefit over simply having a grid connection even in the absence of emergencies or use of arbitrage, and off-grid use filling a niche where current diesel gensets and similar are not able to offer equivalent utility.

[0009] As used herein, the “original battery management system” of the repurposed electric vehicle (EV) battery pack means the battery management system which was used to interface with the EV when the battery pack was in use on an EV, or which was intended to interface with the EV for battery packs built for EVs but never used in that way (e.g. due to excess supply, or to the battery not quite being up to EV standards whilst still having a sufficient energy density to be useful).

[0010] As the unit is mobile, it is easily transportable without an additional license and / or heavy support vehicles. Keeping the weight below 3500 kg may allow towing of the unit on a standard driving license. It may for example be mounted on, or integrated with, a trailer. In contrast with current containerised solutions, this invention is therefore more versatile and cost-effective for small businesses which would otherwise need to hire specialist transport to meet their off-grid energy needs.

[0011] The use of repurposed electric vehicle (EV) battery packs with flexibility on chemistry, capacity and state-of-health creates a pathway for a reuse of EV batteries whilst greatly lowering costs per kWh as compared to currently-available mobile power options, and still ensuring a sufficiently high volumetric and gravimetric energy density to allow the unit’s mobility.

[0012] The dockable battery modules which integrate with the main accumulator again provide greater flexibility to the user. Part of the energy stored can be detached and used away from the mobile unit, and then later re-docked with it for recharging. This creates a centralised hub for decentralised use, so further increasing the flexibility and utility of the unit as a whole. The dockable battery modules may be arranged to be manually liftable, and to be connected and disconnected from the mobile power unit without the use of any tools - they may simply push-fit into the dock, for example.

[0013] The mobile power unit may comprise a plurality of output sockets, each arranged to provide power from at least one of the accumulator and a docked removable battery module.

[0014] A, or the, socket of the unit may be an EV charging socket. The unit may therefore provide EV charging in off-grid locations, as well as providing a mobile EV charger alongside energy storage in on-grid applications. The unit itself may also be chargeable via the same socket - an output socket may therefore also function as an input / charging socket.

[0015] The, or each, dock may be directly connected to the output socket, such that power from a docked removable battery module can be sent to the output socket without passing through the accumulator.

[0016] The or each output socket may be arranged to provide power from both the accumulator and a docked removable battery module. One or more battery modules may therefore be used to provide a boost to the supplied power, beyond what the accumulator could provide alone. In some embodiments, the one or more sockets may be arranged to provide power from the accumulator only.

[0017] The mobile power unit may comprise a plurality of docks, each arranged to releasably receive a removable battery module. The mobile power unit may have between five and twenty docks in some embodiments.

[0018] The mobile power unit may weigh less than 3000 kg, and optionally less than 2500 kg. The mobile power unit may be arranged to store at least 70 kWh, 250 kWh or 300 kWh of energy when fully charged. The accumulator may be arranged to store at least 75%, and optionally at least 80% or 90%, of the total energy stored when the mobile power unit (including all docked battery module(s)) is fully charged.

[0019] A or the output socket may be arranged to output up to a maximum of 300 kW of power. The output socket may therefore be capable of outputting 300 kW of power, whether or not that rated power is reached in normal use. A or the output socket may be rated to provide 300 kW of power, and the accumulator, and optionally the docks, arranged to allow that rated power to be achieved in normal use.

[0020] The accumulator may be arranged for bidirectional energy transfer to and from a docked removable battery module. The docked modules may therefore provide power to the accumulator when desired, and be charged by the accumulator when desired. The docked modules may therefore provide a boost to the accumulator, and / or an extension to the power stored for e.g. grid services, so having a use even when not removed and used separately.

[0021] The or each removable battery module may weigh less than 20 kg, 15 kg, or 10 kg. The or each removable battery module may have an integrated handle. The relatively low mass and / or presence of a handle may facilitate carrying by hand of the removable battery modules.

[0022] The or each removable battery module may have a capacity in the range from 1 kWh to 5 kWh, and optionally may have a capacity of around 2 kWh.

[0023] The accumulator may be arranged to directly charge a docked removable battery module with direct current (DC) power, with no intervening conversion to alternating current (AC).

[0024] The accumulator may comprise a plurality of repurposed electric vehicle battery packs. The repurposed electric vehicle battery packs may be of different battery chemistries and / or of different states of health. The control system may be arranged to make use of the battery packs based on their chemistry and state of health, for example by setting operating ranges within the battery’s most efficient and least damaging state or charge range based on the state of health and / or battery chemistry.

[0025] The mobile power unit may comprise a dedicated charging socket arranged to provide power to the accumulator.

[0026] The control system may be arranged to communicate wirelessly with one or more remote devices (e.g. a server and / or one or more smartphones or other user devices) so as to perform at least one of:

[0027] (i) providing information on the state of the mobile power unit;

[0028] (ii) requesting information on intended usage of the mobile power unit; and

[0029] (iii) receiving instructions to adjust operation of the mobile power unit.

[0030] The control system may be arranged to monitor usage of power from the mobile power unit over time, and may control chagrining and / or discharging, and optionally provide alerts, accordingly. The control system may be arranged to predict future usage based on observed trends, and, on the basis of those predictions, perform at least one of:

[0031] (i) controlling charging or discharging of the mobile power unit; and

[0032] (ii) providing one or more alerts relating to charging or discharging of the mobile power unit.

[0033] The mobile power unit may have dimensions of no more than 2.5 m by 3 m by 5 m, and optionally of no more than 2.5 m by 3 m by 4 m.

[0034] The mobile power unit may further comprise a connector arranged to allow the mobile power unit to be connected to a further mobile power unit as described with respect to this first aspect, so as to provide at least one of a higher power output, and a longer duration output, than could be obtained from either unit individually. Multiple mobile power units may therefore be coupled together once placed in a desired location.

[0035] The mobile power unit may further comprise a mains socket arranged to be connected to a grid. The control system may be arranged to receive live information on energy tariffs and to automatically recharge the accumulator from the grid when the energy tariff falls below a set threshold, and / or automatically discharge the accumulator to the grid (i.e. provide power to the grid) when the energy tariff rises above a set threshold.

[0036] The output socket, or one or more output sockets, of the mobile power unit may be a DC fastcharging electric vehicle socket with a power output of at least 50 kW.

[0037] The output socket, or one or more output sockets, may be arranged to provide power with a voltage of at least 100 V, and optionally of at least 200 V or 300 V.

[0038] The mobile power unit may further comprise feet arranged to raise a lower surface of the mobile power unit off the ground by at least 5 cm. This spacing may improve air flow around the unit, so facilitating cooling, and / or facilitate insertion of forklift forks beneath the unit so as to lift or carry it.

[0039] The mobile power unit may further comprise at least one access hatch arranged to provide access to the accumulator. This may facilitate servicing and maintenance of the unit, as well as potentially facilitating construction.

[0040] According to a second aspect, there is provided a kit of parts comprising:

[0041] (i) a mobile power unit as described with respect to the first aspect; and

[0042] (ii) a plurality of removable battery modules, each arranged to be releasably received in a dock of the mobile power unit.

[0043] The kit of parts may further comprise a carry-case arranged to receive at least one of the plurality of removable battery modules. The carry-case may comprise an output socket and associated electronics. Optionally, each removable battery module does not include any DC-DC or DC-AC converter, any conversion instead being performed by the electronics of the carry -case (or by the electronics of the mobile power unit, when the battery module is docked). The associated electronics may therefore comprise one or more inverters, transformers, converters, or the like.

[0044] The skilled person would understand that features described with respect to one aspect of the invention may be applied, mutatis mutandis, to the other aspect of the invention.

[0045] There now follows, by way of example only, a detailed description of embodiments of the present invention with reference to the accompanying drawings in which:

[0046] Figure 1 is a perspective view of a mobile power unit mounted on a trailer;

[0047] Figure 2 represents a first example of the main internal components of a mobile power unit in accordance with the invention;

[0048] Figure 3 represents a second example of the main internal components of a mobile power unit in accordance with the invention;

[0049] Figure 4 represents a third example of the main internal components of a mobile power unit in accordance with the invention;

[0050] Figure 5 is a side view of a mobile power unit similar to that shown in Figure 1 on a trailer;

[0051] Figure 6 is a perspective view of the mobile power unit and trailer shown in Figure 5;

[0052] Figure 7 is a perspective view of the mobile power unit shown in Figures 5 and 6, with a rear cover closed; Figure 8 is a perspective view of the mobile power unit shown in Figures 5 to 7, with a side hatch open and a cable connected to a socket behind the side hatch;

[0053] Figure 9 is a perspective view of the mobile power unit shown in Figures 5 to 8, with a side wall removed to show inner components;

[0054] Figure 10 is a different perspective view of the mobile power unit shown in Figure 9; and

[0055] Figure 11 is a different perspective view of the mobile power unit shown in Figure 9, with access hatches open.

[0056] In the Figures, like reference numerals are used for like or corresponding features.

[0057] Figure 1 shows a vehicle 1 pulling a trailer 2. The trailer 2 may have a maximum authorised mass (including the mass of the trailer itself and of its load) of 3,500 kg or lower, so allowing it to be towed behind a car in the United Kingdom on a standard British driving license. On the trailer 2 is mounted a mobile power unit 100 of the invention. The mobile power unit 100 and trailer 2 together weighs less than 3500 kg in this implementation. The mobile power unit 100 may have a mass of no more than 3000 kg, and optionally of no more than 2500 kg, 2000 kg, or 1000 kg. The amount of energy stored may be maximised for the allowed mass whilst still providing a robust product with the desired features - e.g. by light-weighting of various components.

[0058] In alternative embodiments, the power unit 100 may instead comprise wheels and a tow bar hitch or similar arranged to allow it to be hitched to a vehicle - the power unit 100 may effectively be or comprise a trailer. In such embodiments, the power unit 100 may have a weight less than or equal to 3500 kg.

[0059] In various implementations, the mass of the power unit 100 may be selected such that the total mass including any trailer 2 is less than or equal to 3500 kg even when the or each dock has a battery module mounted therein, as described below.

[0060] The mobile power unit 100 may have a width of no more than 2.5 m, and optionally no more than

[0061] 2 m. The mobile power unit 100 may have a width of at least 0.6 m and optionally of at least 1 m. For example, in the embodiment pictured in Figure 1, the mobile power unit 100 has a width of 1.9 m. The width may be in the range from 1.5 m to 2 m in various embodiments.

[0062] The mobile power unit 100 may have a height of no more than 3 m, and optionally no more than 2.5 m or 2 m. The mobile power unit 100 may have a height of at least 0.6 m. For example, in the embodiment pictured in Figure 1, the mobile power unit 100 has a width of 1.9 m. As for the width, the height may be in the range from 1.5 m to 2 m in various embodiments. The mobile power unit 100 may be at least substantially square in cross-section.

[0063] The mobile power unit 100 may have a length of no more than 5 m, and optionally no more than

[0064] 3 m. The mobile power unit 100 may have a length of at least 1.5 m. For example, in the embodiment pictured in Figure 1, the mobile power unit 100 has a length of 2.5 m.

[0065] In various embodiments, the mobile power unit 100 may have a width in the range from 1.5 m to 2 m, a height in the range from 1.5 m to 2 m, and a length in the range from 2 m to 5 m.

[0066] The mobile power unit 100 may therefore be described as “mobile” as it is small and light enough to be towed behind a normal road vehicle such as a car, and small and light enough to be transported within a van

[0067] As can be seen in Figure 1, the mobile power unit 100 comprises a plurality of docks 110, each arranged to receive a removable battery module 200. In the example pictured, a total of fifteen docks 110 are provided. In various embodiments, a different number of docks 110 may be provided - for example, just a single dock 110, or up to twenty docks 110.

[0068] In the example 100 pictured, the docks 110 are all located on a rear side (in the orientation shown) of the power unit 100. In alternative implementations, docks 110 may be provided on a different surface of the mobile power unit 100, or on multiple surfaces of the mobile power unit.

[0069] In the example 100 pictured, the docks 110 are all of the same size and shape, and all arranged to receive identical battery modules 200. In alternative implementations, docks 110 may be of a variety of sizes and shapes, and may be arranged to receive different battery modules 200 - for example, smaller modules for lower-power applications and larger modules for higher-power applications.

[0070] The docks 110 of the implementation 100 being described are each provided with a cover 110a. The cover 110a is arranged to prevent water, dust, or debris from entering the dock 110 when no battery module 200 is received therewithin, and may be hinged, retractable, or otherwise mounted so as to move out of the way when a battery module is inserted into the dock. No cover may be provided in other embodiments, or a single cover 144 to shield all docks may be provided as described below.

[0071] Each battery module 200 of the implementation 100 pictured has a handle 202 by which it can be lifted manually. In the implementation shown, the handles 202 extend out of the docks 110 when the modules 200 are mounted in the power unit 100, so facilitating removal of the battery modules 200. In other implementations, the battery module 200 may fit fully within the dock 110 when fully inserted. In such embodiments, the cover 110a may be arranged to cover the handle 202 of the battery module 200 such that the battery module 200 is fully enclosed within the unit 100. The cover 110a may be lockable so as to prevent unauthorised removal of the battery module 200.

[0072] Each removable battery module 200 is arranged to be portable - weighing less than 25 kg, and optionally less than 20 kg, 15 kg, or 10 kg. Each battery module 200 may be arranged to be carried by hand, optionally by use of an integrated handle 202.

[0073] Each removable battery module 200 may have a maximum capacity of around 3 or 5 kWh, and optionally of around 1 kWh or 2 kWh. Each battery module 200 may be arranged to provide power for powered tools or other equipment. In various embodiments, the capacity of individual blocks / battery modules 200 may be in the range 1-5 kWh, and optionally of 1-3 kWh. A total additional capacity provided to the unit 100 by the blocks 200 may be between 2 and 30 kWh. Adding more battery modules 200 to the available docks 110 therefore expands the total capacity of the unit 100.

[0074] Each removable battery module 200 may have at least one output socket, and optionally may have multiple output sockets - e.g. of different types, or to allow two devices with the same type of plug to be plugged into it at once. The battery module 200 may comprise one or more DC-AC converters, and optionally one or more transformers, and / or other power electronics to allow the module’s output to be adjusted to a desired level.

[0075] Alternatively or additionally, each removable battery module 200 may be arranged to be inserted into a carry-case and may have connectors designed to interface with connectors of the carry-case. In such embodiments, the carry-case may comprise one or more output sockets and optionally also one or more converters or transformers, and / or other power electronics. The connection interface, any converters and / or transformers, and any other electronics linking the battery module 200 to the output socket(s) of the carrycase may be referred to as associated electronics of the output socket of the carry -case. A single carry-case may be arranged to receive multiple removable battery modules 200, and may be fully or partially filled with the battery modules 200 according to the power and energy requirements of its intended use. Each battery module 200 may therefore be lighter in such implementations, as the discharging electronics may be provided as part of the carry-case instead of as part of the battery module 200. The mass of the unit 100 with docked battery modules 200 may therefore be reduced, by keeping the mass of the power electronics for each battery module 200 separate (in the carry-case). The carry-case may be as described in the applicant’s other GB patent application filed in the same month as this application and entitled “Portable Power”.

[0076] The mobile power unit 100 is substantially cuboid in shape in the implementation shown, with smoothed or cut-away corners A rib 120 extends around each side perimeter in the implementation shown, effectively providing rails on which the unit 100 rests. These ribs 120 may therefore raise the unit 100 off the ground, which may facilitate placing the unit 100 on a rough or uneven surface (e g. stone-covered terrain of a construction site) without damage to an underside of the unit 100, and may also improve cooling airflow around the unit (it will be appreciated that charging batteries generally generates some heat, at least some of which should be dissipated).

[0077] The ribs 120 may also serve to protect battery modules 200 mounted in the docks 110, the ribs 120 extending further rearward than the handles 202 of the modules 200 and so reducing the chance of the modules 200 being knocked in use.

[0078] The mobile power unit 100 of the implementation shown further comprises at least one socket 102, 103. In embodiments with only one socket 102, the same socket 102 may be used for both charging and discharging the power unit 100 (i.e the socket may be two-way / bidirectional). In embodiments with multiple sockets 102, 103, there may be a separate discharging socket 103 and charging socket 102, or one or more sockets 102, 103 may be two-way. The sockets 102, 103 may be of different types - for example one being a mains plug socket, and the other being a standard electric vehicle charging socket (e.g. Type 1, Type 2, CHAdeMo, or CCS). Alternatively or additionally, one of the sockets, or the socket, may be a heavy-duty socket such as a “Powerlock" connector / socket set or IEC 60309 socket. Powerlock panel source sockets are a type of line source industrial connector that are rated to take currents of up to 660 A. These are typically provided on diesel generators and other heavy industry applications that require a robust and hard-wearing power connector. Each line of the three phases, plus the neutral and the earth, is connected separately (allowing for a higher current but requiring five cables instead of only one five-core cable).

[0079] As for the docks 110, the socket(s) 102, 103 may be provided with a cover to protect them when not in use. Optionally, the cover may be lockable to prevent mis-use.

[0080] The socket(s) 102, 103 may be located on a rear surface of the unit 100, adjacent to the docks 110, or may be located on a front or side surface of the unit 100. In the embodiment shown in Figure 1, the sockets 102, 103 are located on a far side of the unit 100 and so not visible.

[0081] In the embodiment shown, the power unit 100 is provided with ventilation holes 130 on its side faces. These holes 130 may assist with cooling internal components of the unit 100 - allowing air to enter and leave the unit 100. One or more fans are provided within the unit 100 as part of an air-cooling system in the embodiment shown. A liquid cooling system, or other cooling system, or indeed no active cooling system, may be provided in other embodiments.

[0082] In the embodiment shown, the power unit 100 comprises a visual indicator 140 of the state of charge of the unit 100, and more specifically of the state of charge / remaining stored energy of the accumulator 101. The indicator 140 takes the form of an illuminated strip 140, which may comprise a row of lightemitting diodes (LEDs). The length of the illuminated strip (i.e. the number of LEDs lit) may reduce, and / or LED colour may change (e g. from green or blue to amber to red) as the state of charge decreases. Separate indicators for each docked battery module 200 may also be provided, optionally on or adjacent to the relevant dock 110, to provide information on the state of charge of the docked battery module 200. An indicator may be provided on the battery module 200 itself instead of, or as well as, on the unit 100 / dock 110. The dock 110 and / or battery module 200 may also include an indicator, e.g. a light, to show whether or not the battery module 200 is currently being charged - it will be appreciated that a docked battery module 200 which is not fully charged may not be automatically charged to full in all scenarios, for example if the remaining stored energy of that module 200 is predicted to be sufficient for its intended use, if the unit 100 is currently outputting its maximum power and will not have spare charging capacity until after a current charging process is complete, or if maintaining the accumulator energy store is prioritised / if accumulator energy is low. Normally, however, charging of a battery module 200 may commence immediately once it is docked.

[0083] Figures 2 to 4 schematically illustrate key electrical components of the power unit 100.

[0084] The mobile power unit 100 comprises an accumulator 101. The accumulator 101 has a total capacity of at least 40 kWh when fully charged, and of at least 60 kWh, 70 kWh, or 80 kWh when fully charged in some embodiments. In various implementations including that shown in Figure 1, the accumulator 101 has a total capacity in the range from 40 kWh to IMWh, and optionally from 40 kWh to 500 kWh.

[0085] In the example 100 shown in Figure 1, the unit 100 has a total energy storage capacity of 350 kWh. Of this, around 320 kWh of energy is stored in the accumulator 101, with each of the fifteen dockable battery modules 200 providing a further 2 kWh when fully charged (so a contribution of 30 kWh - i.e. just under 9% of the unit’s total stored energy - coming from the battery modules 200).

[0086] In the example 100a pictured in Figure 2 (discussed below), the accumulator 101 has a total capacity of 80 kWh and the battery modules 200 together provide an additional capacity of around 20 kWh, so providing a total energy storage capacity of 100 kWh for the power unit 100 when fully charged. A split of power between the accumulator 101 and the docked battery modules 200 may therefore be around 80:20. In other embodiments, for example in embodiments with fewer and / or smaller battery modules 200, the proportions may be different, for example 85: 15, 90: 10, or 95:5. At least 75% of the stored energy may be stored within the accumulator 101 in various embodiments.

[0087] The accumulator 101 of each embodiment comprises at least one repurposed battery pack from an electric vehicle (EV). The power unit 100 may therefore provide a “second life” for the repurposed EV battery pack. The repurposed EV battery pack comprises its original battery management system as used in the EV. “Repurposed” in this context means a fully -functional battery pack taken from an electric vehicle, e g. a car, that is not deemed to be roadworthy due to one or more faults not directly relevant to the battery pack in question (e g. electrical, mechanical, or cosmetic damage to other vehicle parts). Power units 100 of embodiments of the invention are arranged to access the existing battery management system, keeping the battery pack as a whole with no disassembly. There is therefore no need to match cells / modules based on aging as conventional second-life applications do (it will be appreciated that this is an expensive and time-consuming process which requires a lot of stock in the first place). This reduces the cost of the battery and additional management components to well below that of typical second-life applications, and plugs a gap in the circular economy. Further, multiple repurposed EV battery packs of different types, and optionally from vehicles of different types and / or from different manufacturers, may be used within the same accumulator 101. As such, a single accumulator 101 may include batteries of different chemistries - e g. LFP, nickel-rich chemistries such as NMC, NCA, and others including lithium ion, sodium ion, or lithium- air batteries. Having a variety of battery packs of different chemistries available may improve flexibility and performance by making use of the benefits of each type. A control system 150 may be programmed accordingly, with knowledge of the different battery pack types. The control system 150 may be arranged to have suitable interfaces for multiple known battery management system types.

[0088] Multiple different batteries / battery packs may be connected together to form the accumulator 101, optionally all in parallel. Battery packs may be arranged in series to increase output voltage, and / or a DC- DC converter may be used to change the output voltage. Arranging the batteries in parallel rather than series may increase the available runtime of the power unit 100 while maintaining the voltage, and may provide more resilience in that if one of the batteries fails, the remaining batteries in the system can still provide power. However, wiring batteries in parallel means that the system voltage will be lower, resulting in a higher current draw - the higher current necessitates thicker cables and more voltage drop. The lower voltage may also result in a need for more DC-DC conversion of the output for various applications - larger power appliances are generally less efficient when operating at lower voltages. Whilst parallel battery arrangements are used in the units 100 being described, batteries of the accumulator 101 may be arranged in series in other implementations, for example depending on expected system demands. Similarly, whilst the docks 110 are electrically connected in parallel in the examples discussed herein, alternative arrangements are also envisaged and the scope of the invention is not to be limited to any particular layout of circuitry.

[0089] Whilst it may be desirable to get as much power as possible from e g. a 3,000 kg system so as to maximise energy storage in a trailer-transportable unit 100, power density requirements may not be as stringent as for electric vehicles in some implementations. As such, repurposed EV battery packs with a state of health / degradation level too low for use in a new EV may still be usefully incorporated into a mobile power unit 100 as described herein, so providing a second use for a battery pack which might otherwise need to undergo an expensive dismantling and recycling process for parts or materials to be reused.

[0090] The accumulator 101 may therefore comprise multiple repurposed battery packs from electric vehicles. Additionally or alternatively, the accumulator 101 may comprise one or more other power sources - for example different (optionally new or recycled or repurposed) batteries, and / or one or more ultracapacitors or other energy storage devices.

[0091] Each dock 110 arranged to releasably receive a removable battery module 200 is electrically connected to the accumulator 101 as indicated by the dashed arrows in Figures 2 to 4, such that the accumulator 101 can be used to charge each docked removable battery module 200. A battery module 200 may therefore be removed from the unit 100 for use, at least partially drained (e.g. by being used to power a tool), and then returned to the unit for re-charging. One or more DC-DC converters, and / or other power electronics, may be provided between the accumulator 101 and the docks 110 to adjust the accumulator’s output to suit the battery modules 200.

[0092] The dashed arrows in Figures 2 to 4 are arranged to figuratively illustrate power flows, and are not necessarily representative of the underlying circuity - for example, the docks 110 may all be connected together in parallel in various embodiments.

[0093] At least one output socket 102 is arranged to provide power from the accumulator 101 to a device plugged into the socket 102. The output socket 102 may be a DC output socket or an AC output socket. It will be appreciated that a DC to AC converter, or bidirectional converter, may be provided in association with the socket 102, or between the socket 102 and the accumulator 101, when the output socket 102 is an AC socket. One or more step-up or step-down transformers, and / or other power electronics, may be provided to adjust the accumulator’s output as required for a given output socket 102. At least one input / charging socket 103 is arranged to provide power to the accumulator 101, and optionally directly to one or more docked battery modules 200. The charging socket 103 may be AC or DC, and one or more converters, inverters, transformers, and / or other power electronics may be provided between the socket 103 and the accumulator 101 and / or docks 110.

[0094] In the example 100a pictured in Figure 2, the unit 100 comprises two output sockets 102a, 102b. The first output socket 102a is a mains socket and the second output socket is an EV charging socket 102b. The mains socket 102a may provide 230 V AC power. The EV charging socket 102b may be arranged to provide a DC fast-charging output of at least 50 kW.

[0095] A DC output socket 102b may be arranged to provide a DC voltage source in the range of 200 V to 1000 V.

[0096] The unit 100 also comprises a control system 150 arranged to monitor and control power flows within the unit 100. The control system 150 controls power flows between the accumulator 101, socket(s) 102, 103, and dock(s) 110. One or more sensors - e.g. humidity and / or temperature sensors - may be provided as part of the control system 150, or arranged in communication therewith, to provide data on unit conditions. One or more current and / or voltage sensors may also be provided to verify inputs and / or outputs.

[0097] The control system 150 is arranged to interface (either directly or indirectly) with the at least one original battery management system of a repurposed EV battery pack within the accumulator 101 so as to control power drawn from, or fed to, that repurposed EV battery pack and optionally also to monitor the battery pack’s status. The internal monitoring systems (e.g. including circuitry and sensors) of the original EV battery pack management system may therefore be re-used along with the batteries themselves. The control system 150 may be arranged to have connectors and interfaces adapted to couple to and communicate with a variety of standard EV battery management systems so as to accommodate repurposed EV battery packs from a variety of (potentially heterogeneous) sources.

[0098] In the example 100a shown in Figure 2, all power flows are to or from the accumulator 101, and the control system 150 may be integrated with the accumulator.

[0099] In the example 100a shown in Figure 2, the unit 100 is provided with a dedicated charging (input) socket 103, and two dedicated output sockets 102a, 102b. The charging socket 103 is used to charge the accumulator 101, and the accumulator then provides power to the plurality of docks 110a - 1 lOn, so allowing any docked battery modules 200 to be charged. All power flows are uni-directional in this example 100a - the battery modules 200 cannot provide power to the accumulator 101 or output socket(s) 102.

[0100] In the example 100b shown in Figure 3, all power flows are again to or from the accumulator 101, and the control system 150 may be integrated with the accumulator in some implementations, although it is shown separately from the accumulator 101.

[0101] In this example, the output socket 102 is also the charging socket - only a single unit socket is provided and power flow between the socket 102 and the accumulator 101 is bi-directional. Power flow between the docks 110 and the accumulator 101 is also bidirectional - any docked battery modules 200 with stored power can therefore be used to recharge the accumulator 101 if / when desired.

[0102] It will be appreciated that these features are separable - e.g. separate dedicated charging and output sockets 102, 103, or multiple bi-directional sockets, may be provided with bi-directional flow between the docks 110 and the accumulator 101 in some implementations.

[0103] In the example 100c shown in Figure 4, some power flows circumvent the accumulator 101, and the control system 150 is shown separately from the accumulator 101 accordingly. In this example, the docks 110 are electrically connected to the bi-directional socket 102 directly, allowing any docked battery modules 200 to be directly charged (e.g. by connection to the mains) or discharged (e.g. to power a connected device) without that power flowing through the accumulator 101. Such an arrangement may be beneficial for high- power, and / or high-voltage outputs, such as DC fast charging, so that the output can be powered from the main accumulator 101 with a simultaneous boost from the removable blocks 200.

[0104] A separate charging socket 103 connected to only the accumulator 101 is also shown in this example - this socket 103 may be a relatively high-power socket, e.g. for EV charging, and may not be suitable for charging the smaller battery modules 200 without additional electrical conversion.

[0105] It will be appreciated that these specific implementations lOOa-lOOc are not intended to be limiting, and are simply described by way of example.

[0106] In various implementations, the power unit 100 may have reconfigurable power connectors on the input and output, such that any 3-phase or 1-phase connector, or a combination of different types of connectors, can be provided on the unit, e.g. on a socket panel of the unit which comprises multiple sockets within a set area, providing single phase and / or three phase AC output. For example, a socket panel, or other arrangement of sockets 102, 103 on a mobile power unit 100, may comprise:

[0107] • A 32 A, 63 A, or 125 A three phase socket, and three single phase 16 A sockets (e.g. each being a CEE-type 16A single phase, or an IEC 60309 16A single phase socket providing 230 V)

[0108] • Two 32 A or 63A single phase sockets and three single phase 16 A sockets;

[0109] • Two 32 A or 63A single phase sockets only;

[0110] • Powerlock set of five sockets only (optionally one set, two sets, or three sets of Powerlock sockets, comprising LI, L2, L3, N, and PE connections);

[0111] • One or more Powerlock socket sets and also three 16 A single-phase sockets; or

[0112] • Two or three 16 A single phase sockets only.

[0113] Additionally or alternatively, one or more 16 A three phase sockets may be provided (e g. each being a CEE- type 16A three phase, or an IEC 60309 16A three phase socket, or a commando 16A three phase socket. 415 V output may be provided). In general, a blue colour of the socket 102 or socket cover may be used to indicate single-phase power, and red may be used to indicate three-phase power. Sockets 102 rated for larger currents are generally larger than 16 A sockets.

[0114] In most implementations, a mobile power unit 100 is manufactured with socket panels with a specific configuration of sockets 102, 103. Different mobile power units 100 may be provided with different combinations of sockets 102, 103, and this combination may not be changeable, or at least not easily changeable, in use.

[0115] In some implementations, some reconfiguration “in the field” may be facilitated. For example, a plurality of Powerlock connectors may be provided, all feeding into a distribution block, such as “Power Cubes” provided by Titan Power Ltd. The distribution block may have reconfigurable connectors, such that each customer / user can customise the output as desired.

[0116] The control system 150 of various implementations, including those lOOa-c pictured, may be arranged to include communications capabilities, for example for remote monitoring and / or control of the unit 100. This remote communication may be performed via the cloud, for example using the MQTT (Message Queuing Telemetry Transport) protocol. It will be appreciated that any wireless communication protocol may be used in other implementations.

[0117] An alert may be provided by the control system 150 to one or more remote users or managers when unit power is running low, to trigger recharging, or when a docked battery module 200 is fully charged and ready for use. Live updates of remaining capacity may be provided on demand, optionally along with a state of charge of the accumulator 101 and each docked battery module 200. A warning may also be issued if unit temperature is rising towards a safety cut-off, to allow remedial action to be taken before a safety system might otherwise cut power to, and optionally from, the unit 100.

[0118] The control system 150 may also be arranged to take action in response to received messages - e g. an instruction to change prioritisation of charging of docked battery modules 200, or to send energy to the grid.

[0119] The control system 150 of various implementations, including those lOOa-c pictured, may be arranged to provide predictive load forecasting - for example based on past usage metrics and / or user input relating to planned upcoming power demands. The system 150 may send alerts to request user feedback on day-ahead main accumulator 101 and block 200 usage, or estimated usage over other time periods as appropriate.

[0120] In embodiments in which the unit 100 is used with a grid connection (e.g. due to a charging socket 103 being plugged in throughout a usage period, even if no current is drawn from the grid in the majority of that period), for example for energy arbitrage purposes, the feedback on intended use, and / or past state-of- charge monitoring, may be used to decide when to take energy from the grid, and how much. For example, if estimated mobile power unit use if high, more energy may be taken from the grid, and / or energy may be taken from the grid at higher-cost times than usual, to keep the accumulator 101 topped up. Similarly, the data may be used to decide when to feed energy to the grid, and how much.

[0121] The energy transfer pattern to and from the main accumulator 101 and the blocks 200 may be selflearned following rules provided by a manufacturer, user, or system administrator, and may be optimised based on usage patterns. Alternatively or additionally, the energy transfer pattern implemented can be directly configured by a user.

[0122] For example, the unit controller 150 may be programmed to prioritise keeping the docked blocks 200 charged (such that these are available for use on demand), and may use energy from the accumulator 101 to power a device plugged into the unit 100, only using docked blocks 200 to provide power via the output socket 102 once the accumulator 101 is running low on stored energy (or potentially if a voltage or power boost is needed).

[0123] Given that the power unit 100 can be used for on-grid and off-grid applications, optimal use - and therefore the rules set - will generally be different in the two scenarios. In general, rules may be more complex for an on-grid system.

[0124] For an on-grid system, for example, the power unit 100 may be connected to a building and may “learn” the load pattern of that building with time, so becoming able to predict when the unit 100 should be fully charged, and when energy is needed the most. Other inputs to decision-making software may be the current energy tariff, the predicted energy tariff over the next 24 hour period, any contracts with National Grid (or an equivalent mains power supplier or manager) and Distribution Network Operators (DNOs) for grid services. Minimisation of battery degradation may also be considered, e.g. by assigning that a monetary value to battery state of health in an optimisation algorithm.

[0125] The control system 150 of the unit 100 may be arranged to receive live information on energy tariffs and to automatically recharge the accumulator 101 from the grid when the energy tariff falls below a set threshold, and / or to automatically provide power from the accumulator 101 to the grid when the energy tariff rises above a set threshold. The thresholds may each be a user-entered value, or may vary dynamically depending on the state of charge of the accumulator 101 and the predicted load on the unit 100 over the next 4, 6, 12, or 24 hours, and / or other factors.

[0126] For off-grid systems, the rules are generally much simpler and may simply reflect a desired split of power or prioritisation between accumulator 101 power (for direct loads on the unit 100) and battery module 200 power (keeping removable batteries charged for flexible, portable, power). Points to be considered in optimising energy management may therefore include one or more of:

[0127] • Maximising revenue from grid services (e.g. participating as a battery asset supplying power to the grid as part of a balancing mechanism and ancillary services);

[0128] • Maximising customer energy savings (e.g. by choosing when to draw power from the grid, and storing that power for use or grid export when tariffs are higher);

[0129] • Minimising battery degradation (generally by operating in an optimum operating range for a given battery / battery chemistry: e.g. temperature control, keeping within 20-80% state of charge limits, low charging currents, etc.);

[0130] • Maintaining a buffer for emergencies (optionally at a user-configurable level or at a level set based on past usage history); and

[0131] • Making sure removable blocks 200 are charged ready for when they are expected to be used.

[0132] The use of removable, dockable, battery modules 200 therefore provides a plurality of flexibility features to the whole system 100 including some or all of the below in various implementations:

[0133] • Dynamic load management: modules 200 can be used to provide surge / peak power needs to supplement that provided by the main accumulator 101;

[0134] • Bidirectional energy transfer to and from the main accumulator 101 (modules 200 can be charged by the main accumulator 101 in all embodiments, and can also discharge energy to charge the main accumulator 101 in some embodiments);

[0135] • Modules 200 be hot-swapped in and out from the system 100 even under load, so providing flexible, on-demand use;

[0136] • Modules 200 can be removed to provide remote power to appliances far away from the main unit 100, and optionally in areas that would be awkward for the main unit 100 to reach (e g. for tool usage within pipes, upstairs, or in relatively small or hard to access structures);

[0137] • The energy transfer pattern to and from the main accumulator 101 and the blocks 200 may be selflearned and optimised based on usage patterns or can be configured by the user, so allowing the operation of the unit 100 to be tailored for each use-case;

[0138] • The system (including the unit 100 and any devices in communication therewith, e.g. computers or smartphones of users, administrators, or managers, and also potentially one or more servers, e.g. in the cloud) may have predictive load forecasting and may provide customer alerts to request user feedback on day -ahead main accumulator 101 and block 200 usage, and / or to give live alerts if power may be exhausted; and

[0139] • The blocks 200 can be moved from one unit 100 to another, and may be docked in different positions on the same unit 100 (remote communications from the control system 150 on a large site with multiple units 100 may include informing a user of a location of the nearest unit 100 with an available dock 110 for recharging and / or the nearest unit 100 with an available fully-charged battery module 200). In various embodiments, a plurality of mobile power units 100 may be coupled together - physically and optionally also digitally / electronically - so allowing for the flexible management of additional stored energy and optionally also for a higher power or voltage output from a given socket 102 than otherwise possible, and / or for a longer duration of output power from a given socket 102 than would otherwise be possible for an off-grid system. For example, up to ten mobile power units 100 may be coupled together in this way in some implementations. A dedicated coupling interface (not shown) may be provided for this coupling of units 100.

[0140] In various embodiments, the accumulator 101 may be used to charge the battery modules 200 (and optionally vice versa) directly with DC power - no DC-AC-DC conversion may therefore be required for power exchange between the accumulator 101 and docked blocks 200, so reducing weight as compared to off-grid battery rechargers which use AC power. System weight may be reduced by avoiding a need for any AC conversion between the accumulator 101 and docks 110.

[0141] One or more DC-DC converters / transformers may be provided to adjust the power flowing between the accumulator 101 and the battery modules 200 as appropriate. For example, the power output from the accumulator may be at around 200 V, whereas that for the battery modules 200 may be in the range from 50-60 V.

[0142] A DC-AC converter may be provided between the accumulator 101 and an AC output socket 102, and optionally between one or more of the docks 101 and an AC output socket 102. An AC-DC converter may be provided between an AC charging socket 103 and the accumulator 101, and optionally between an AC input socket 103 and one or more of the docks 101. One or more bidirectional converters may be used in some implementations.

[0143] Various embodiments of the invention therefore provide a mobile energy storage solution 100 mountable on a trailer 2, and which can be used for both on-grid businesses and remote power.

[0144] Figures 5 to 10 show a mobile power unit 100 similar to that shown in Figure 1. To avoid repetition, the below discussion of the embodiment of Figures 5 to 10 focuses on differences between the two embodiments, with features otherwise generally being as described with respect to Figure 1.

[0145] The mobile power unit 100 of Figures 5 to 10 has ribs 120 extending around each side of the unit 100, but these ribs 120 only extend outwardly by a small distance - e.g. 1-5 cm - from the main body. By contrast, the ribs of the embodiments of Figure 1 may extend outwardly by 4-15 cm, and optionally by 10- 15 cm. Feet 122 are provided on a lower surface of the unit 100 in the embodiment of Figures 5 to 10, the feet being generally arranged around a lower perimeter of the unit 100. The feet 122 extend further than the ribs 120, for example extending downwardly by 5-20 cm from an underside of the unit’s main body. The feet 122 are arranged to support the weight of the unit 100, and to facilitate placing it on uneven ground. Raising the unit 100 off the ground (or another surface on which it rests) in this way may improve cooling of the unit 100 by allowing airflow beneath the unit 100. In addition, these feet 122 may allow standard forklift forks to be able to lift the unit 100 - the height of the feet 122 allows forks to clear the underside of the unit 100 easily.

[0146] The unit 100 shown in Figures 5 to 10 has a side hatch or door 142. The side hatch 142 opens - in this embodiment by pivoting around a vertical hinge, although a sliding door, rolling door, multiple hinges, or other mechanism may be employed in other embodiments - to reveal one or more sockets 102, 103. Each socket 102, 103 may be independently labelled or may be visually distinguishable due to being of a different socket type (e.g. 2-pin mains, 3-pin mains, or any mains plug known around the world, such as Types A to G, or Type 1 EV charging, Powerlock, and IEC 60309, etc.). Each socket 102, 103 may be provided with an individual cover.

[0147] In the embodiment 100 shown, a total of three sockets 102a, 102b, 103 are located behind the side hatch 142. The sockets 102, 103 may be described as being provided on a socket panel in this implementation, as they are located together on a single surface - in other implementations, the sockets may be located differently. A charging socket 103, which is a standard EV charging socket in the example shown, is used to charge the unit 100, and is shown connected to a charging cable 3 in Figure 8. A plug of the charging cable 3 is received within the charging socket 103.

[0148] In alternative embodiments, some or all sockets 102, 103 may be arranged to be two-way instead of dedicated to charging the unit 100 or being an output socket.

[0149] The side hatch 142 may be lockable, and may cover and protect the sockets 102, 103 when not in use. The side hatch 142 may have a water-proof or water-resistant seal to the rest of the unit 100 to reduce or prevent water ingress.

[0150] In some embodiments, an electronic display may be provided within the hatch 142, optionally showing states of charge of each docked battery module 200, occupancy of each dock 110, and / or state of charge of the main accumulator 101. A user interface may be provided to allow a user to view desired data, for example historical usage profiles for the last day or week, and optionally to input data or instructions. Safety information and / or operating instructions may also be provided within the hatch 142, optionally printed on the inside of the door 142 itself.

[0151] As shown in Figure 7, this mobile power unit 100 also has a rear hatch 144 which can cover all of the docks 110 when the unit 100 is not in use. The hatch 144 may be designed to allow the battery modules 200 mounted in docks 110 to be completely enclosed within the unit 100 as shown in Figures 7 and 11, covering any mounted modules 200, or may instead have apertures for the battery modules 200 to pass therethrough, as shown in Figures 8 and 9.

[0152] In various implementations, especially implementations in which the battery modules 200 can be inserted and removed with the hatch 144 closed, the hatch 114 may be arranged to be opened only for maintenance or servicing, and may generally be locked, or may require a specific tool (e.g. a hex key of a particular size) to open it.

[0153] A front hatch 146 as shown in Figures 10 and 11 may also be provided, and may similarly be arranged to be opened only for maintenance or servicing. The two hatches 144, 146 may therefore provide easy access to the internal components, and may, for example, allow a new accumulator 101 to be added, or an extant accumulator 101 to be replaced. The hatches 144, 146 may also facilitate assembly and wiring of the mobile power unit 100.

[0154] The hatches 144, 146, which may also be referred to as access hatches or doors, are hinged at the top in the implementations pictured, and have gas struts 147 to keep them open under their own weight. It will be appreciated that any suitable design known in the art may be used in other implementations. Further, only one of a front hatch and a rear hatch may be provided in some embodiments instead of both, and / or a side access hatch may be provided instead.

[0155] The mobile power unit 100 shown in Figures 5 to 10 has just three docks 110, as shown in Figures 9 and 10, so allowing up to three battery modules 200 to be docked at any one time. The battery modules 200 are arranged to be inserted horizontally, as indicated by the arrow, A, in Figure 9. In alternative embodiments, the docks 110 may be angled instead of horizontal - for example being angled inwardly and downwardly with respect to the unit 100, which may reduce the risk of a module 200 becoming dislodged and sliding out, e.g. if the unit 100 is placed on sloped ground and knocked, or towed uphill without a cover 144 in place. The battery modules 200 may be locked or clipped in place within the docks 110 in some embodiments, so avoiding risks of accidental removal.

[0156] Figures 9 and 10 illustrate some internal components 101a, 101b, 150 of the mobile power unit 100. In particular, this mobile power unit 100 has an accumulator 101 comprising two repurposed EV battery packs 101a, 101b. Just a single repurposed EV battery pack 101, or more than two repurposed EV battery packs 101, may be present in other accumulators 101. The accumulator 101 shown consists of the two repurposed EV battery packs 101 and associated circuitry, control systems and power electronics 150. In other embodiments, the accumulator 101 may comprise one or more additional energy storage devices as well as the one or more repurposed EV battery packs 101. For example, one or more capacitors, or other batteries, may form a part of the accumulator 101.

[0157] It will be appreciated that Figures 9 and 10 represent only some of the main internal components of the unit 100. Circuitry connecting the accumulator 101 to the sockets 102, 103 is not shown, for example, and there may be additional power electronics, cooling systems, user interface electronics, temperature and / or humidity sensors, safety cut-out mechanisms, and / or other unshown components.

[0158] In the embodiment shown, the three docks 110 are connected to a first part 150a of the control system 150. That first part 150a of the control system is also connected to the first repurposed EV battery pack 150a. The second part 150b of the control system is connected to the second repurposed EV battery pack 150a and is not connected to the docks 110.

[0159] In the embodiment shown, any docked battery modules 200 are charged by the first repurposed EV battery pack 150a, and may also provide energy to the first repurposed EV battery pack 150a. The docks 110 are not electrically connected to the second repurposed EV battery pack 150b, so cannot transfer power directly to or from that battery pack 150b. In some embodiments, the two repurposed EV battery packs 150 may be electrically coupled such that one, or either, can be used to charge the other directly. In other embodiments, direct power transfer between the two battery packs 150 may not be possible, and the state of charge of each may be managed by choosing from which to draw power for an output socket 102, and to which to feed power from a charging socket 103. The two parts 150a, 150b of the control system 150 may be communicatively coupled but not electrically coupled in such embodiments.

[0160] It will be appreciated that many different wiring and connection arrangements are possible, and that the specific examples described herein are not limiting.

[0161] The unit 100 shown in Figures 5 to 11 has ventilation holes 130 in a grid arrangement across a rearward part of both side walls. The regions covered by these ventilation holes 130 align with the repurposed battery pack 101a, 101b interconnections and the control and monitoring systems and power electronics 150 (which serve to adjust power for energy transfer between batteries and the grid, and between batteries), so providing cooling for these components - the accumulator 101 may comprise on or more powered fans to improve air cooling of components. Ventilation holes 130 in different locations, and / or one or more vents of other types, may be provided additionally or alternatively in other embodiments.

[0162] The control system and power electronics 150 allow control of energy flows to and from the unit 100, and within the unit 100, to be controlled to meet demand and / or to utilise fluctuations in grid energy prices to save money (or even make a profit) for the user. If usage profiles allow, when to charge the unit 100 from the grid can be decided based on when energy tariffs are lowest, and some implementations may also support energy being exported back to the grid when demand on the unit is sufficiently low and energy tariffs are higher. A unit 100 such as that shown in Figure 1 or Figures 5-11 can therefore bridge the gap between two separate markets: mobile temporary power solutions (off-grid) and stationary Battery Energy Storage System (BESS) (on-grid).

[0163] The unit 100 is therefore a single product with a dual purpose - as a replacement in an established market for diesel gensets (mimicking the electrification of vehicles), and / or as an addition to a growing market for commercial energy storage. The unit 100 therefore provides flexibility in use over its lifetime for a given owner, and for re-sale.

[0164] Currently, carbon-intensive diesel generators are used on construction sites, at events and by utility companies, and cause local pollution (both chemical and particulate emissions and noise pollution). Currently, containerised BESS solutions are bulky, inflexible, difficult to transport and operate, and have a high cost of installation. In both markets, a unit 100 as pictured in Figure 1 will appeal to customers as it provides both a cleaner and quieter off-grid / temporary power solution and a more flexible, cheaper to install, more permanent energy storage solution. As a replacement for existing fossil-fuel mobile power solutions, a mobile unit 100 as described herein can therefore address an existing market where there is a need to rapidly reduce CO2 emissions. The accumulator 101 and removable batteries 200 can also act as energy storage to provide the flexibility to lower overall costs through peak shaving, load shifting and arbitrage, without impacting on productivity. The units 100 therefore enable electricity to be stored during periods of low demand and cost, and then used during peak demand periods, either exclusively off-grid, or to prevent grid supply capacity being exceeded or incurring additional costs.

[0165] The opportunity for energy arbitrage exists in both markets (off-grid power and energy storage), either as a primary purpose or a secondary benefit. For some users, the potential for arbitrage may not be possible given the operating profile of system (e.g. use at night, recharge during the day), but for other users it may simply never have been considered previously due to limitations of available power units, and may now provide an additional revenue stream for an operator. Mobile power units 100 as described herein can therefore fulfil a diverse range of applications for a diverse range of customers, each with differing benefits to the end customer, for example as listed in Table 1 below.

[0166] It will be appreciated that the usages listed in Table 1 are provided by way of example only, and are not intended to be limiting.

[0167] As an on-grid BESS, a mobile power unit 100 as described herein may support moderate users of electricity with a typical daily consumption of 100-500 kWh a day, or 3-10 MWh a month, for example within the following sectors:

[0168] • Airports - private and commercial;

[0169] • Higher Education - e.g. universities, colleges;

[0170] • Food and Drink - including breweries, catering, bakeries;

[0171] • Manufacturing - all types, including fabrication, welding, injection moulding;

[0172] • Media - e.g. newspaper printing, TV and film production;

[0173] • Retail - primarily supermarkets;

[0174] • Commercial services - printers, laundry etc. ; and

[0175] • Pharmaceutical - laboratories, testing, R&D.

[0176] As off-grid remote power, the diesel genset (in stationary or portable formats) is currently the de facto autonomous and stand-alone power source to provide local power where transmission and distribution from a grid source is inaccessible. The need for remote power is often a temporary requirement due to the nature of activities conducted on construction sites, infrastructure projects etc. Common uses of portable diesel generators include the below, and it will be appreciated that mobile power units 100 as described herein could be used in place of diesel gensets in any of these scenarios: Construction; Infrastructure; Mining; Oil & Gas Operations; TV & film production; Events / Festivals; and Military operations and installations.

[0177] It will therefore be appreciated that mobile power units 100 as described herein have a wide range of commercial applications and the potential to decarbonise many commercial operations as well as to assist with grid balancing, which is becoming ever more important with the rise in renewable energy providers to the grid and small-scale domestic to the grid providers (e.g. home solar installations).

Claims

CLAIMS1. A mobile power unit weighing less than 3500 kg and comprising: an accumulator with a total capacity of at least 40 kWh, the accumulator comprising at least one repurposed battery pack from an electric vehicle, the repurposed battery pack comprising its original battery management system; a removable battery module; a dock arranged to releasably receive the removable battery module, the dock being electrically connected to the accumulator such that the accumulator can be used to charge a docked removable battery module; an output socket arranged to provide power from at least one of the accumulator and a docked removable battery module to a device plugged into the socket in use; and a control system arranged to interface with the at least one original battery management system and to control power flows between the accumulator, socket, and dock.

2. The mobile power unit of Claim 1, comprising a plurality of output sockets, each arranged to provide power from at least one of the accumulator and a docked removable battery module.

3. The mobile power unit of Claim 1 or Claim 2, wherein the or each output socket is arranged to provide power from both the accumulator and a docked removable battery module.

4. The mobile power unit of any preceding claim, comprising a plurality of docks, each arranged to releasably receive a removable battery module, and wherein optionally the mobile power unit has between five and twenty docks.

5. The mobile power unit of any preceding claim, wherein the mobile power unit weighs less than 3000 kg, and optionally less than 2500 kg.

6. The mobile power unit of any preceding claim, wherein the mobile power unit is arranged to store at least 250 kWh of energy when fully charged, and optionally at least 300 kWh.

7. The mobile power unit of any preceding claim, wherein the accumulator is arranged to store at least 75% of the total energy stored when the mobile power unit is fully charged, and optionally at least 80%.

8. The mobile power unit of any preceding claim, wherein the output socket is arranged to output up to a maximum of 300 kW of power.

9. The mobile power unit of any preceding claim, wherein the accumulator is arranged for bidirectional energy transfer to and from a docked removable battery module.

10. The mobile power unit of any preceding claim, wherein the or each removable battery module:(i) weighs less than 20 kg, 15 kg, or 10 kg;(ii) has an integrated handle; and / or(iii) has a capacity in the range from 1 kWh to 5 kWh, and optionally around 2 kWh.

11. The mobile power unit of any preceding claim, wherein the accumulator is arranged to directly charge a docked removable battery module with DC power, with no intervening conversion to AC.

12. The mobile power unit of any preceding claim, wherein the accumulator comprises a plurality of repurposed electric vehicle battery packs, the repurposed electric vehicle battery packs optionally being of different battery chemistries and / or of different states of health.

13. The mobile power unit of any preceding claim, further comprising a dedicated charging socket arranged to provide power to the accumulator.

14. The mobile power unit of any preceding claim, wherein the dock is directly connected to the output socket, such that power from a docked removable battery module can be sent to the output socket without passing through the accumulator.

15. The mobile power unit of any preceding claim, wherein the control system is arranged to communicate wirelessly with one or more remote devices so as to perform at least one of:(i) providing information on the state of the mobile power unit;(ii) requesting information on intended usage of the mobile power unit; and(iii) receiving instructions to adjust operation of the mobile power unit.

16. The mobile power unit of any preceding claim, wherein the control system is arranged to monitor usage of power from the mobile power unit over time, predict future usage based on observed trends, and, on the basis of those predictions, perform at least one of:(i) controlling charging of the mobile power unit; and(ii) providing one or more alerts relating to charging or discharging of the mobile power unit.

17. The mobile power unit of any preceding claim, wherein the mobile power unit has dimensions of no more than 2.5 m by 3 m by 5 m, and optionally no more than 2.5 m by 3 m by 4 m.

18. The mobile power unit of any preceding claim, further comprising a connector arranged to allow the mobile power unit to be connected to a further mobile power unit as described in any preceding claim so as to provide at least one of a higher power output, and a longer duration output, than could be obtained from either unit individually.

19. The mobile power unit of any preceding claim, further comprising a mains socket arranged to be connected to a grid, and wherein the control system is arranged to receive live information on energy tariffs and to automatically recharge the accumulator from the grid when the energy tariff falls below a set threshold.

20. The mobile power unit of any preceding claim, wherein the output socket is a DC fast-charging electric vehicle socket with a power output of at least 50 kW.

21. The mobile power unit of any preceding claim, wherein the output socket provides power with a voltage of at least 100 V, and optionally of at least 200 V or 300 V.

22. The mobile power unit of any preceding claim, further comprising feet arranged to raise a lower surface of the mobile power unit off the ground by at least 5 cm.

23. The mobile power unit of any preceding claim, further comprising at least one access hatch arranged to provide access to the accumulator.

24. A kit of parts comprising:(i) a mobile power unit as described in any preceding claim; and(ii) a plurality of removable battery modules, each arranged to be releasably received in a dock of the mobile power unit.

25. The kit of parts of Claim 24, further comprising a carry-case arranged to receive at least one of the plurality of removable battery modules, the carry-case comprising an output socket and associated electronics, and wherein optionally each removable battery module does not include any DC-DC or DC-AC converter, any conversion instead being performed by the electronics of the carry-case.

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