EP4639671A1

EP4639671A1 - Battery assembly

Info

Publication number: EP4639671A1
Application number: EP23837249.4A
Authority: EP
Inventors: Mark Collins; James HAYBITTLE
Original assignee: Ocado Innovation Ltd
Current assignee: Ocado Innovation Ltd
Priority date: 2022-12-24
Filing date: 2023-12-20
Publication date: 2025-10-29
Also published as: GB202219766D0; CN120359655A; AU2023410638A1; GB2625812A; WO2024133483A1; KR20250124229A; JP2025541488A

Abstract

A battery assembly is provided, comprising a battery pack comprising an outer battery pack casing and a base electrical connector; and a service box. The service box comprises an outer service box casing, an intermediate electrical connector and an end electrical connector. The intermediate electrical connector is electrically coupled to the end electrical connector, and the intermediate electrical connector and the base electrical connector are configured to reversibly connect to each other. The battery pack casing is releasably attached to the service box casing to form a single unit in which the base electrical connector is connected to the intermediate electrical connector, and the end electrical connector is externally exposed to allow the battery pack to electrically couple to an external device via the service box. The end electrical connector is mounted to the service box casing such that the end electrical connector can move relative to the service box casing in a direction substantially perpendicular to the connecting direction of the end electrical connector. A battery exchange system is provided, comprising the battery assembly and an external device comprising a battery compartment configured to removably receive the battery assembly. The battery compartment comprises a compartment electrical connector configured to reversibly connect to the end electrical connector of the battery assembly to electrically couple the battery assembly to the external device. A storage and retrieval system is provided, comprising a storage structure and the battery exchange system. A method of servicing the battery assembly is provided.

Description

BATTERY ASSEMBLY

TECHNICAL FIELD

The present invention relates to a battery assembly for use in a battery exchange system.

BACKGROUND

Some commercial and industrial activities require systems that enable the storage and retrieval of a large number of different products. W02015019055A1 describes a storage and retrieval system in which stacks of storage containers are arranged within a grid storage structure. The system further comprises remotely operated load handling devices configured to move on tracks located on the top of the grid storage structure. To access the containers in the grid storage structure, the load handling devices are equipped with a container-holding device for releasably gripping a container at the top of a stack and a lifting assembly for raising and lowering the container.

Each load handling device is powered by a rechargeable battery. The rechargeable battery is typically charged in situ by driving a load handling device to a charging station located at the edge of the grid storage structure. The load handling device remains stationary at the charging station while the battery is recharged. The charging period is a significant source of downtime for the load handling device and can be on the order of hours.

To alleviate the problem of charging downtime, the load handling device may be powered by an exchangeable battery pack. When the battery pack in the load handling device is depleted, the depleted battery pack is exchanged for a fully charged battery pack and therefore the charging downtime is reduced to the time it takes to exchange the battery pack, rather than being the time to charge the battery pack.

Frequent exchanging of the battery packs into and out of the load handling devices will result in wear and tear of the battery packs. The present invention aims to alleviate problems relating to wear and tear of the battery packs.

SUMMARY OF INVENTION

The invention is defined in the accompanying claims. The present invention provides a battery assembly comprising: a battery pack comprising an outer battery pack casing and a base electrical connector; and a service box comprising an outer service box casing, an intermediate electrical connector and an end electrical connector, wherein the intermediate electrical connector is electrically coupled to the end electrical connector, and the intermediate electrical connector and the base electrical connector are configured to reversibly connect to each other; wherein the battery pack casing is releasably attached to the service box casing to form a single unit in which the base electrical connector is connected to the intermediate electrical connector, and the end electrical connector is externally exposed to allow the battery pack to electrically couple to an external device via the service box; wherein the end electrical connector is mounted to the service box casing such that the end electrical connector can move relative to the service box casing in a direction substantially perpendicular to the connecting direction of the end electrical connector.

The service box thus acts as a sacrificial interface between the battery pack and an external device to minimise wear and tear of the base electrical connector of the battery pack during the lifetime of the battery pack. In particular, by arranging the end electrical connector of the battery assembly on the service box, the base electrical connector of the battery pack will not undergo any mating cycles every time the battery assembly is connected to an external device. Therefore, when the end electrical connector needs to be replaced, only the service box needs to be replaced, rather than the battery pack itself. Servicing a battery pack will typically require more time and skill compared to just replacing the service box and therefore the battery assembly of the present invention can be serviced more quickly, efficiently, and cost- effectively.

Another advantage of replacing the service box rather than servicing a battery pack is that the service box reduces the need for battery packs to be transported. Battery packs are classified as hazardous goods, so shipping may be costly because of the need to comply with regulations. Service boxes can be repaired easily on site, or shipped to another site or to the supplier for repair. Since service boxes are much lighter than battery packs and not hazardous, shipping is relatively inexpensive.

Spare service boxes can be stored onsite at the storage facility, so when a faulty service box needs to be replaced, the faulty service box can be replaced with a spare service box. Repairing a service box (for example, replacing the connectors) is not only a simpler task but also does not carry the same risks as repairing a battery pack, since the electrical connectors in a service box are not live. The battery pack itself does not need to be taken out of service for repair.

The service box casing is releasable (detachable) from the battery pack casing to allow the service box to be replaced or repaired.

The battery pack casing and the service box casing may be rigid, i.e. made from a rigid material. The service box casing may be made from metal, e.g. sheet metal. Alternatively, the service box may be injection moulded plastic.

The base electrical connector may be mounted on or supported by (directly or indirectly) the battery pack casing. The intermediate electrical connector and the end electrical connector may be mounted on or supported by (directly or indirectly) on the service box casing. The end electrical connector may be mounted on or supported by (directly or indirectly) by the service box casing.

The battery pack casing may be releasably attached to the service box casing such that the base electrical connector and the intermediate electrical connector are prevented from disconnecting while the battery pack casing is attached to the service box casing.

The base electrical connector, the intermediate electrical connector and the end electrical connector may each be power connectors configured to allow power to be transferred from the battery pack to an external device via the service box and/or vice versa.

The service box may comprise a fuse coupled between the intermediate electrical connector and end electrical connector.

The connecting direction of the end electrical connector may be different to the connecting direction of the intermediate electrical connector. The connecting direction of the end electrical connector may be substantially perpendicular to the connecting direction of the intermediate electrical connector. The intermediate electrical connector may be arranged to connect to the base electrical connector in a horizontal direction and the end electrical connector may be arranged to connect to an electrical connector of an external device in a vertical direction. The connecting direction of an electrical connector is defined as the direction in which the electrical connector is configured to connect to (mate with) a corresponding electrical connector. The service box casing may be releasably attached to the battery pack casing by one or more fasteners, e.g. screws, or nuts and bolts.

At least one of the battery pack casing and the service box casing may comprise a flange. The service box casing may be releasably attached to the battery pack casing via the flange.

The battery pack may comprise a guide feature configured to cooperate with a corresponding guide feature of the service box such that the base electrical connector is aligned for connection with the intermediate electrical connector and the battery pack casing is aligned for attachment to the service box casing. The guide feature of the battery pack may be a protrusion and the corresponding guide feature of the service box may be an aperture or recess, or vice versa.

The end electrical connector may be limited to moving relative to the service box casing up to a predetermined distance.

The end electrical connector may comprise at least one alignment member for cooperating with at least one corresponding alignment feature of an external electrical connector to align the end electrical connector with the external electrical connector to allow the end electrical connector to connect to the external electrical connector. The at least one alignment member may comprise a protrusion or a recess extending in a direction parallel to the connecting direction of the end electrical connector.

The base electrical connector may be mounted on the battery pack casing such that the base electrical connector can move relative to the battery pack casing in a direction substantially perpendicular to the connecting direction of the base electrical connector. The base electrical connector may be limited to moving relative to the battery pack casing up to a predetermined distance.

The intermediate electrical connector may be mounted on the service box casing such that the intermediate electrical connector can move relative to the service box casing in a direction substantially perpendicular to the connecting direction of the intermediate electrical connector. The intermediate electrical connector may be limited to moving relative to the service box casing up to a predetermined distance.

The base electrical connector and the intermediate electrical connector may be blind mate connectors. The end electrical connector may be a blind mate connector. The service box may comprise a cable assembly comprising one or more electrical cables. The intermediate electrical connector may be electrically coupled to the end electrical connector by one or more electrical cables of the cable assembly. The cable assembly may be housed within the service box casing.

The battery pack may comprise a plurality of base electrical connectors. The service box may comprise a plurality of intermediate electrical connectors and a plurality of end electrical connectors. Each intermediate electrical connector may be electrically coupled to a respective end electrical connector. Each intermediate electrical connector may be configured to reversibly connect to a respective base electrical connector. The battery pack casing may be releasably attached to the service box to form a single unit in which the each base electrical connector is connected to a respective intermediate electrical connector. Each end electrical connector may be externally exposed to allow the battery pack to electrically couple to an external device via the service box. The plurality of end electrical connectors may include a plurality of connector modules forming a single modular electrical connector.

At least one of the plurality of base electrical connectors may be a power connector, at least one of the plurality of intermediate electrical connectors may be a power connector and at least one of the plurality of end electrical connectors may be a power connector to allow power to be transferred from the battery pack to an external device via the service box and/or vice versa.

The battery pack may further comprise a battery management system. At least one of the plurality of base electrical connectors may be a base signal connector electrically coupled to the battery management system, at least one of the plurality of intermediate electrical connectors may be a signal connector, and at least one of the plurality of end electrical connectors may be a signal connector to allow signals to be transferred from the battery management system to an external device via the service box and/or vice versa.

The present invention also provides a battery exchange system comprising the battery assembly defined above and an external device comprising a battery compartment configured to removably receive the battery assembly. The battery compartment may comprise a compartment electrical connector configured to reversibly connect to the end electrical connector of the battery assembly to electrically couple the battery assembly to the external device. The compartment electrical connector may be a power connector. Once electrically coupled, the battery assembly may deliver power to one or more electrical and/or electronic components of the external device. In the case where there are a plurality of base electrical connectors, intermediate electrical connectors, and end electrical connectors, the battery compartment may comprise a plurality of compartment electrical connectors, each compartment electrical connector being configured to reversibly connect to a respective end electrical connector of the battery assembly.

The battery exchange system may further comprise a robotic arm configured to move the battery assembly into and out of the battery compartment.

The battery exchange system may further comprise a battery station comprising one or more bays configured to removably receive the battery assembly and a charging system for charging the battery assembly. Each bay may comprise an electrical connector configured to reversibly connect to the end connector of the battery assembly to electrically couple the battery assembly to the charging system. The robotic arm may be further configured to move the battery assembly into and out of the bays and move the battery assembly between the battery compartment of the external device and the bays of the battery station.

The battery assembly may have an outer battery assembly casing defined by the battery pack casing and the service box casing. The battery assembly may further comprise one or more locating members mounted on the battery assembly casing, wherein the locating members are configured to allow the battery assembly to self-locate into the battery compartment when being moved into the battery compartment. The locating members may extend in a direction parallel to the connecting direction of the end connector. The locating members may comprise one or more tapered surfaces.

The battery compartment may be configured to receive the battery assembly in a downwards direction. The service box may be releasably attached to a lateral side the battery pack. The end electrical connector and the compartment electrical connector may be configured to connect in a vertical direction.

The external device may be a load handling device for lifting and moving containers arranged in stacks in a storage structure, the storage structure comprising a track structure, the track structure comprising a first set of tracks and a second set of tracks, the first set of tracks extending in a first direction and the second set of tracks extending in a second direction, the second direction being substantially perpendicular to the first direction, to form a grid pattern defining a plurality of grid cells above the stacks of containers, the load handling device comprising: a driving assembly configured to move the load handling device on the track structure; a container-holding device configured to releasably hold a container from above; and a lifting mechanism configured to raise and lower the container-holding device.

The load handling device may comprise an external body and the battery compartment may be externally exposed to allow the battery assembly to be moved into and out of the battery compartment from and to a location outside the external body of the load handling device.

The present invention also provides a storage and retrieval system comprising: a storage structure comprising: a track structure, the track structure comprising a first set of tracks and a second set of tracks, the first set of tracks extending in a first direction and the second set of tracks extending in a second direction, the second direction being substantially perpendicular to the first direction, to form a grid pattern defining a plurality of grid cells; and a plurality of upright members configured to support the track structure from below to define a storage area below the track structure for storing a plurality of stacks of containers below each grid cell; and wherein the storage and retrieval system further comprises the battery exchange system as defined above.

The present invention also provides a method of assembling the battery assembly defined above. The method comprises the steps of:

(i) coupling the battery pack and the service box to connect the base electrical connector to the intermediate electrical connector; and

(ii) attaching the service box casing to the battery pack casing.

The present invention also provides a method of disassembling the battery assembly defined above. The method comprises the steps of:

(i) detaching the service box casing to the battery pack casing; and

(ii) separating the battery pack and the service box to disconnect the base electrical connector from the intermediate electrical connector.

The present invention also provides a method of servicing the battery assembly defined above, wherein the service box of the battery assembly is a first service box. The method comprises the steps of:

(i) detaching the first service box casing from the battery pack casing; (ii) separating the first service box from the battery pack to disconnect the base electrical connector from the intermediate electrical connector;

(iii) coupling a second service box and the battery pack to connect the base electrical connector to the intermediate electrical connector of the second service box; and

(iv) attaching the service box casing of the second service box to the battery pack casing.

The end connector of the second service box may have undergone fewer mating cycles than the end connector of the first second service box (at the time the first service box is replaced with the second service box).

The present invention also provides a method of servicing the battery assembly defined above. The method comprises the steps of:

(i) detaching the service box casing from the battery pack casing;

(ii) separating the service box from the battery pack to disconnect the base electrical connector from the intermediate electrical connector;

(iii) replacing or fixing at least one component of the service box;

(iv) coupling the service box and the battery pack to mate the first base electrical connector to the first service box electrical connector; and

(v) attaching the service box casing to the battery pack casing.

The at least one component in step (iii) may include the end electrical connector.

Step (i) of either of the above two methods of servicing the battery assembly may be carried out after the end connector has undergone a predetermined number of mating cycles.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 is a schematic perspective view of a grid storage structure and containers arranged within the grid storage structure.

Figure 2 is a schematic plan view of a track structure on top of the storage structure of Figure 1. Figure 3 shows load handling devices on top of the track structure of the storage structure of Figure 1 .

Figure 4 is a schematic perspective view of a load handling device with a container-holding device in a position below the bottom of the load handling device.

Figure 5 is a schematic perspective view of the load handling device of Figure 4 with a side portion of the external body omitted from view to show a container-receiving space.

Figure 6 is a schematic perspective view of the load handling device of Figure 5 with a container occupying the container-receiving space.

Figure 7 is a perspective view of a battery assembly within a battery compartment of the load handling device.

Figure 8 is an exploded view of Figure 7 showing the battery assembly outside the battery compartment

Figure 9 is a schematic perspective view of the load handling device shown in Figure 6 on which an example region for locating the battery compartment is marked.

Figure 10 is a schematic perspective view of an alternative external body for the load handling device, comprising corner blocks together connected by horizontal and vertical connecting elements to form an open frame structure.

Figure 11 is a perspective view of the battery assembly comprising a service box attached to a battery pack.

Figure 12 is a perspective view of the battery pack in isolation.

Figure 13 is a perspective view of a service box in isolation showing the side which couples to the battery pack.

Figure 14 is a perspective view of the service box showing the side opposite to that shown in Figure 13.

Figure 15A is a bottom perspective view of an end connector of the service box. Figure 15B is a top perspective view of the end connector.

Figure 16 is a top perspective view of an electrical connector of the battery compartment for connecting to the end connector of the service box.

Figure 17 is a perspective view of the inside of the service box without the end connector.

Figure 18A is a perspective view of the inside of the service box with the end connector mounted on the outer casing of the service box.

Figure 18B shows the same view as 18A with a nut and washer removed from each alignment pin of the end connector.

Figure 19 is a perspective view showing the cable assembly housed by the service box.

Figure 20 is a schematic perspective view of a gantry robotic arm operating above the track structure of the grid storage structure shown in Figure 1.

Figure 21 is a schematic perspective view of an articulated robotic arm operating adjacent to the track structure of the grid storage structure shown in Figure 1.

Figure 22 is a schematic perspective view of a battery station comprising bays for holding battery assemblies.

Figure 23 is a block diagram showing an example control system of a storage and retrieval system.

DETAILED DESCRIPTION

Figure 1 shows an example storage structure 1 that may be used in a storage and retrieval system to store storage containers 9. The storage structure 1 comprises a framework comprising upright members 3 and horizontal members 5, 7 which are supported by the upright members 3. The horizontal members 5 extend parallel to one another and the illustrated x- axis. The horizontal members 7 extend parallel to one another and the illustrated y-axis, and transversely to the horizontal members 5. The upright members 3 extend parallel to one another and the illustrated z-axis, and transversely to the horizontal members 5, 7. The horizontal members 5, 7 form a grid pattern defining a plurality of grid cells 14. In the illustrated example, storage containers 9 are arranged in stacks 11 beneath the grid cells 14 defined by the grid pattern, one stack 11 of storage containers 9 per grid cell 14.

Figure 2 shows a large-scale plan view of a section of track structure 13 forming part of the storage structure 1 illustrated in Figure 1 and located on top of the horizontal members 5, 7 of the storage structure 1 illustrated in Figure 18. The track structure 13 may be provided by the horizontal members 5, 7 themselves (e.g. formed in or on the surfaces of the horizontal members 5, 7) or by one or more additional components mounted on top of the horizontal members 5, 7. The illustrated track structure 13 comprises x-direction tracks 17 and y- direction tracks 19, i.e. a first set of tracks 17 which extend in the x-direction and a second set of tracks 19 which extend in the y-direction, transverse to the tracks 17 in the first set of tracks 17. The tracks 17, 19 define apertures 15 at the centres of the grid cells 14. The apertures 15 are sized to allow storage containers 9 located beneath the grid cells 14 to be lifted and lowered through the apertures 15. The x-direction tracks 17 are provided in pairs separated by channels 21 , and the y-direction tracks 19 are provided in pairs separated by channels 23. Other arrangements of track structure may also be possible.

Figure 3 shows a plurality of load handling devices 25 moving on top of the storage structure 1 illustrated in Figure 18. The load handling devices 25, hereinafter referred to as “bots”, are provided with sets of wheels to engage with corresponding x- or y-direction tracks 17, 19 to enable the bots 25 to travel across the track structure 13 and reach specific grid cells 14. The illustrated pairs of tracks 17, 19 separated by channels 21 , 23 allow bots 25 to occupy (or pass one another on) neighbouring grid cells 14 without colliding with one another.

As illustrated in Figure 4, a bot 25 comprises an external body 27 in or on which are mounted one or more components which enable the bot 25 to perform its intended functions. These functions may include moving across the storage structure 1 on the track structure 13 and raising or lowering storage containers 9 (e.g. from or to stacks 11) so that the bot 25 can retrieve or deposit storage containers 9 in specific locations defined by the grid pattern.

The illustrated bot 25 comprises a driving assembly comprising first and second sets of wheels 29, 31 which are mounted on the external body 27 of the bot 25 and enable the bot 25 to move in the x- and y-directions along the tracks 17 and 19, respectively. In particular, two wheels 29 are provided on the shorter side of the bot 25 visible in Figure 4, and a further two wheels 29 are provided on the opposite shorter side of the bot 25. The wheels 29 engage with tracks 17 and are rotatably mounted on the external body 27 of the bot 25 to allow the bot 25 to move along the tracks 17. Analogously, two wheels 31 are provided on the longer side of the bot 25 visible in Figure 4, and a further two wheels 31 are provided on the opposite longer side of the bot 25. The wheels 31 engage with tracks 19 and are rotatably mounted on the external body 27 of the bot 25 to allow the bot 25 to move along the tracks 19.

To enable the bot 25 to move on the different wheels 29, 31 in the first and second directions, the driving assembly further comprises a wheel-positioning mechanism (not shown) for selectively engaging either the first set of wheels 29 with the first set of tracks 17 or the second set of wheels 31 with the second set of tracks 19. The wheel-positioning mechanism is configured to raise and lower the first set of wheels 29 and/or the second set of wheels 31 relative to the external body 27, thereby enabling the load handling device 25 to selectively move in either the first direction or the second direction across the tracks 17, 19 of the storage structure 1 .

The wheel-positioning mechanism may include one or more linear actuators, rotary components or other means for raising and lowering at least one set of wheels 29, 31 relative to the external body 27 of the bot 25 to bring the at least one set of wheels 29, 31 out of and into contact with the tracks 17, 19. In some examples, only one set of wheels is configured to be raised and lowered, and the act of lowering the one set of wheels may effectively lift the other set of wheels clear of the corresponding tracks while the act of raising the one set of wheels may effectively lower the other set of wheels into contact with the corresponding tracks. In other examples, both sets of wheels may be raised and lowered, advantageously meaning that the external body 27 of the bot 25 stays substantially at the same height and therefore the weight of the external body 27 and the components mounted thereon does not need to be lifted and lowered by the wheel-positioning mechanism.

The bot 25 also comprises a lifting assembly 33 and a container-holding device 37 configured to raise and lower storage containers 9. The illustrated lifting assembly 33 comprises four tethers 35 which are connected at their lower ends to the container-holding device 37. The tethers 35 may be in the form of cables, ropes, tapes, or any other form of tether with the necessary physical properties to lift the storage containers 9. The container-holding device 37 comprises a gripping mechanism 39 configured to engage with features of the storage containers 9 to releasably hold the containers 9 from above. In the illustrated example, the gripping mechanism 39 comprises legs that can be received in corresponding apertures 10 in the rim of the storage container 9 and then moved outwards to engage with the underside of the rim of the storage container 9. The tethers 35 can be wound up or down to raise or lower the container-holding device 37 as required. One or more motors and winches or other means may be provided to effect or control the winding up or down of the tethers 35. In Figure 5 and Figure 6, a side portion of the external body 27 of the bot 25 has been omitted from view to allow the interior of the bot 25 to be seen. The external body 27 of the illustrated bot 25 has an upper portion 41 and a lower portion 43. The upper portion 41 is configured to house or support one or more operation components (not shown), such as components of the lifting assembly 33 (e.g. motors), wireless communication components, a bot control system comprising one or more bot controllers for controlling operation of the bot 25, etc. The lower portion 43 is arranged beneath the upper portion 41. The lower portion 43 is externally open at the bottom and defines a container-receiving space 45 for accommodating at least part of a storage container 9 that has been raised into the container-receiving space 45 by the lifting assembly 33. Figure 5 shows the container-receiving space 45 before it is occupied by a storage container 9 and Figure 6 shows the container-receiving space 45 after it has been occupied by a storage container 9. The container-receiving space 45 is sized such that enough of a storage container 9 can fit inside the space 45 to enable the bot 25 to move across the track structure 13 on top of storage structure 1 without the underside of the storage container 9 catching on the track structure 13 or another part of the storage structure 1. When the bot 25 has reached its intended destination, the lifting assembly 33 controls the tethers 35 to lower the container-holding device 37 and the corresponding storage container 9 out of the space 45 and into the intended position. The intended position may be a stack 11 of storage containers 9 or an egress point of the storage structure 1 (or an ingress point of the storage structure 1 if the bot 25 has moved to collect a storage container 9 for storage in the storage structure 1). Although in the illustrated example the upper and lower portions 41 , 43 are separated by a physical divider, in other examples, the upper and lower portions 41 , 43 may not be physically divided by a specific component or part of the external body 27 of the bot 25. The upper and lower configuration of the bot 25 allows the bot 25 to occupy only a single grid cell 14 on the track structure 13 of the storage system 1 .

In an alternative example, the container-receiving space 45 of the bot 25 may not be within the external body 27 of the bot 25. For example, the container-receiving space 49 may instead be adjacent to the external body 27 of the bot 25, e.g. in a cantilever arrangement with the weight of the external body 27 of the bot 25 counterbalancing the weight of the container 9 to be lifted. In such embodiments, a frame or arms of the lifting assembly 33 may protrude horizontally from the external body 27 of the bot 25, and the tethers 35 may be arranged at respective locations on the protruding frame/arms and configured to be raised and lowered from those locations to raise and lower a storage container 9 into the container-receiving space 45 adjacent to the external body 27. Figure 7 and Figure 8 show a battery assembly 100 for powering the bot 25 and a battery compartment 80 of the bot 25 for receiving the battery assembly 100. Figure 7 shows the battery assembly 100 within the battery compartment 80 and Figure 8 is an exploded view of Figure 7 with the battery assembly 100 outside of the battery compartment 80. The battery compartment 80 comprises sidewalls 84 defining a substantially cuboidal battery-receiving space and a top opening for receiving the battery into the battery-receiving space in a downwards direction. The battery compartment 80 may further comprise a base from which the sidewalls 84 extend to support the bottom of the battery assembly 100, or another portion of the bot 25 may provide support. The battery compartment 80 further comprises an electrical connector 82 for connecting to (mating with) an externally exposed electrical connector 152 of the battery assembly 100 when the battery assembly 100 is inserted into the battery compartment 80. Hereafter, the electrical connector 152 of the battery assembly 100 will be referred to as the “end connector” 152 and the electrical connector 82 of the battery compartment 80 will be referred to as the “compartment connector” 82.

In this example, the end connector 152 and the compartment connector 82 are orientated to connect in a vertical direction. In particular, the end connector 152 points downwards and the compartment connector 82 points upwards. Furthermore, the end connector 152 and the electrical connector 82 of the battery compartment 80 are blind mate connectors such that when the battery assembly 100 is inserted into the battery compartment 80, the end connector 152 connects to (mates with) the electrical connector 82 in the battery compartment 80 automatically without requiring any other tools. The compartment connector 82 is electrically coupled to electrical and/or electronic components of the bot 25 such that once the battery assembly 100 is received in the battery compartment 80 and connected to the compartment connector 82, the battery assembly 100 is electrically coupled to the bot 25 to provide power to the one or more electrical components of the bot 25, such as the driving assembly, the lifting assembly 33, the container-holding device 37, wireless communication components, the bot control system, etc.

Figure 9 shows the view of the bot 25 from Figure 6 with a region 48 demarcated with dotted lines. The battery compartment may be located anywhere within the region 48. For example, the battery compartment may be located fully within the external body 27 of the bot 25, or the battery compartment may extend through the top side 28 of the external body 27 of the bot 25, or the battery compartment 80 may be fully located above the external body 27 of the bot 25.

The battery compartment 80 is also externally exposed such that the battery-receiving space is externally accessible from a location above the external body 27 of the bot 25. The top side 28 of the external body 27 of the bot 25 comprises an opening 47. In the case where the battery compartment 80 is fully within the external body 27 of the bot 25, the opening 47 may be in communication with the top opening of the battery compartment 80. This allows the battery assembly 100 to be directly inserted into the battery compartment 80 via the opening 47 from a location above the top side 28 of the external body 27 of the bot 25, and directly removed from the battery compartment 80 via the opening 47 to a location above the top side 28 of the external body 27 of the bot 25. In the case where the battery compartment 80 extends through the top side 28 of the external body 27 of the bot 25, the battery compartment 80 may extend through the opening 47. In the case where the battery compartment 80 is fully located above the external body 27 of the bot 25, the battery compartment 80 may be mounted on top side 28 of the external body 27 of the bot 25 and the opening 47 may not be required.

The external body 27 of the bot 25 illustrated in Figure 9 is defined by a top panel and side panels. Figure 10 shows another example of the external body 27 of the bot 25 which comprises corner blocks 60 connected by horizontal connecting elements 62a and vertical connecting elements 62b (e.g. rods) to form an open frame structure. The open frame structure can be used to house and/or support components of the bot 25, such as the driving assembly and the lifting assembly 33. Due to the open frame structure of the external body, the top side of the external body 27 has an opening 47 formed by the corner blocks 60 and the horizontal connecting elements 62a at the top side of the bot 25. Similar to the bot 25 shown in Figure 9, the battery compartment 80 can be fully located within the external body 27 of the bot 25 and communicate with the opening 47, or can extend through of the opening 47 of the external body 27 of the bot 25, or can be fully located above the external body 27 of the bot 25.

Figure 11 is a perspective view of the battery assembly 100 in isolation. The battery assembly 100 comprises a battery pack 110 and a service box 130 releasably attached to a lateral side of the battery pack 110 to form a single rigid assembly that can be moved as a single unit.

The overall shape of the battery assembly 100 is substantially cuboidal. The battery assembly 100 comprises four locating members 102 extending along four vertical edges between the corners of the battery assembly 100. The locating members 102 comprise tapered surfaces 103 such that when the battery assembly 100 is being inserted into the battery compartment 80, the tapered surfaces 103 of the locating members 102 can engage with the sidewalls 84 of the battery compartment 80 to self-locate the battery assembly 100 into the battery compartment 80. Figure 12 shows the battery pack 110 in isolation. The battery pack 110 comprises an outer battery pack casing 112 which houses battery cells and a battery management system (BMS) for managing the battery cells. The battery pack 110 is preferably rechargeable. The BMS comprises one or more controllers configured to monitor the state of the battery pack 110. For example, the BMS may monitor at least one of: voltage, temperature, current, battery health, and state of balance of the battery cells.

The battery pack 110 further comprises a power connector 120 and a signal connector 122 arranged on a connecting face 114 of the battery pack casing 112. Hereafter, the power connector 120 and the signal connector 122 of the battery pack 110 will be referred to as the “base power connector” 120 and the “base signal connector 122” respectively. The connecting face 114 of the battery pack casing 112 of the battery pack 110 is the face which faces the service box 130 when the battery pack 110 and the service box 130 are attached. In this example, the connecting face 114 faces a horizontal direction when the battery assembly 100 is orientated for insertion into the battery compartment 80 and the base power connector 120 and the base signal connector 122 are orientated for connecting to corresponding electrical connectors in a horizontal direction. The base power connector 120 may be any suitable electrical connector for connecting to a corresponding power connector of an external device to allow power to be transferred between the battery pack 110 and the external device. The base signal connector 122 is electrically coupled to the BMS and may be any suitable electrical connector for connecting to a corresponding signal connector of an external device to allow signals or data to be transferred between the BMS and the external device. When the battery pack 110 is in isolation (i.e. not attached to the service box 130), the base power connector 120 and the base signal connector 122 are externally exposed on the connecting face 114 of the battery pack casing 112.

Figure 13 shows the service box 130 in isolation showing the side which faces the battery pack 110 when the battery assembly 100 is assembled. The service box 130 comprises an outer service box casing 112 having a connecting face 134 which faces the connecting face 114 of the battery pack 110 when the service box 130 and the battery pack 110 are attached. The service box casing is made from a substantially rigid material, such as sheet metal, to form a rigid structure. The service box 130 further comprises a power connector 140 and a signal connector 142 arranged on the connecting face 134. Hereafter, the power connector 140 and the signal connector 142 on the connecting face 134 of the service box 130 will be referred to as the “intermediate power connector” 140 and the “intermediate signal connector” 142 respectively. When the service box 130 is in isolation (i.e. not attached to the battery pack 110), the intermediate power connector 140 and the intermediate signal connector 142 are externally exposed on the connecting face 134 of the service box casing 132.

The intermediate power connector 140 is configured to connect to (mate with) the base power connector 120 and the intermediate signal connector 142 is configured to connect to (mate with) the base signal connector 122. Given that the base connectors 120, 122 are orientated to connect in a horizontal direction, the intermediate connectors 140, 142 are also orientated to connect in a horizontal direction. In this illustrated example, the intermediate connectors 140, 142 are male connectors and the base connectors 120, 122 are female connectors for safety reasons (e.g. to reduce the risk of short-circuiting the battery pack 110), but the male and female connectors could be reversed. The base and intermediate power connectors 120, 140 and signal connectors 122, 142 are also blind mate connectors in that the connectors mate via the action of pushing the connecting face 114 of the battery pack 110 towards the connecting face 134 of the service box 130 without requiring any other tools.

With reference to Figures 11-13, the battery pack 110 and the service box 130 attach to each other via screws 104 received in screw holes 118 in the battery pack casing 112 and screw holes in the 138 in the service box casing 132. The screw holes 118 in the battery pack casing 112 and the screw holes 138 in the service box casing 118 are arranged such that they are aligned for receiving the screws 104 when the base connectors 120, 122 are connected to the intermediate connectors 140, 142. To facilitate attachment of the service box 130 to the battery pack 110, the service box casing 132 comprises flanges 135 through which the screw holes 138 of the service box 130 are defined. Alternatively, the battery pack casing 112 could comprise the flanges, or both the service box casing 132 and the battery pack casing 132 could comprise flanges through which the screw holes 118, 138 are defined. The battery pack 110 and the service box 130 are also not limited to being attached together by screws. Other types of fasteners could be used, e.g. bolts and nuts, or any other suitable type of releasable attachment means may be used, e.g. interlocking portions on the battery pack casing 112 and the service box casing 132 which snap-fit together.

Once the battery pack casing 112 and the service box casing 132 are attached, the battery pack 110 and the service box 130 are not able to move relative to each other and therefore the base connectors 120, 122 and the intermediate connectors 140, 142 are prevented from disconnecting from each other until the battery pack casing 112 and the service box casing 132 have been detached. With continued reference to Figures 11-13, the battery pack casing 112 comprises two guide pins 116 extending from the connecting face 112 in a direction parallel to the connecting direction of the base connectors 120, 122, and the service box casing 132 comprises two corresponding guide apertures 136 for receiving the two guide pins 116 when the connecting faces 114, 134 are moved towards each other. The purpose of the guide pins 116 and guide apertures 136 is to facilitate alignment of the base connectors 120, 122 with the intermediate connectors 140, 142 and alignment of the screw holes 118, 138 of the battery pack casing 112 and the service box casing 132 when the battery pack 110 and the service box 130 are being coupled together. The guide pins 116 and the guide apertures 136 are arranged such that when the guide pins 116 are aligned with the guide apertures 136, the base connectors 120, 122 are aligned for connecting with the intermediate connectors 140, 142 and the screw holes 118 of the battery pack casing 112 are aligned with the screw holes 138 of the service box casing 132. Therefore, moving the battery pack 110 and the service box 130 towards each other such that the guide pins 116 are received in the guide apertures 136 will result in the base connectors 120, 122 connecting to the intermediate connectors 140, 142 and the battery pack casing 112 and the service box casing 132 being aligned for attachment.

Alternatively, the service box 130 could comprise the guide pins 116 and the battery pack 110 could comprise the guide apertures 136. Furthermore, the guide pins 116 could be any form of protrusion and the guide apertures 136 could be any form of aperture or recess for receiving the protrusion. In general, the battery pack 110 and the service box 130 each comprise one or more guide features which cooperate to align the battery pack 110 and the service box 130 such that the base connectors 120, 122 and the intermediate connectors 140, 142 are aligned for connection and the battery pack casing 112 and the service box casing 132 are aligned for attachment.

Figure 14 shows the side of the service box 130 opposite to that shown in Figure 13, with the locating members 102 removed to aid visibility of the other components. The end connector 152 is part of an end connector assembly 150 which is mounted on the service box casing 132 such that the end connector 152 is externally exposed once the battery pack 110 and the service box 130 are attached together. As mentioned above, the end connector 152 is arranged to point downwards for connecting to the upward facing connector 82 of the battery compartment 80 when the battery assembly 100 is inserted into the battery compartment 80.

Figures 15A and 15B show the end connector assembly 150 in isolation. Figure 15A shows the bottom (external-facing) side of the end connector assembly 150 and Figure 15B shows the top (internal-facing) side of the end connector assembly 150. The end connector 152 in this illustrated example is a modular connector comprising a power connector module 152a and a signal connector module 152b mounted together within a frame 153 such that the end connector 152 can move as a single unit. The power connector module 152a and the signal connector modules 152b may be considered as a power connector and a signal connector in their own right, but for the purposes of describing this example, they will continue to be referred to collectively as a single end connector 152. The end connector assembly 150 comprises a support plate 154 on which the end connector 152 is mounted. The support plate 154 comprises a through-opening in which the end connector 152 is located such that the bottom side of the end connector 152 is exposed on the bottom side of the support plate 154 and the top side of the end connector 152 is exposed on the top side of the support plate 154. The end connector assembly 150 further comprises two alignment pins 156 mounted on the support plate 154, each alignment pin 156 extending through a respective aperture in the support plate 154. Each alignment pin 156 comprises a bottom (external-facing) portion 156a extending downwards (i.e. in a direction parallel to the connecting direction of the end connector 152) from the bottom side of the support plate 154 such that the alignment pins 156 protrude past the bottom side of the end connector 152. Each alignment pin 156 further comprises a top (internal-facing) portion 156b extending upwards from the top side of the support plate 154. The top portion 156b and the bottom portion 156a of the alignment pins 156 have a substantially cylindrical shape. The bottom portion 156a also tapers radially inwards to form a conical or frusto-conical distal end. The end connector 152 and the alignment pins 156 are all rigidly connected to the support plate 154 such that the end connector assembly 150 moves as a single unit.

Figure 16 shows the top side of an example compartment connector 82 which can connect to (mate with) the bottom side of the end connector 152. The compartment connector 82 is also a modular electrical connector comprising a power connector module 82a and a signal connector module 82b. In this illustrated example, the power and signal connector modules 82a, 82b of the compartment connector 82 are male connectors and the power and signal connector modules 152a, 152b of the end connector 152 are female connector modules for safety reasons (e.g. to reduce the risk of short-circuiting the battery pack 100 once the service box 130 attached) but the male and female connectors could be reversed. The compartment connector 82 further comprises alignment apertures 83 for receiving the alignment pins 156 of the end connector assembly 150 when the battery assembly 100 is being inserted into the battery compartment 80. The alignment apertures 83 are positioned with respect to the power connector module 82a and the signal connector module 82b of the compartment connector 82 such that when the alignment pins 156 are aligned with the alignment apertures 83, the power and signal connector modules 82a, 82b of the compartment connector 82 and the end connector 152 are aligned for connection. The tapered distal ends of the alignment pins 156 help the alignment pins 156 to self-locate into the alignment recesses 83 as the end connector 152 approaches the compartment connector 82.

Figure 17 shows the inside of the service box casing 132 when it is empty. The portion of the service box casing 132 on which the end connector assembly 150 is mounted comprises a central opening 144 for receiving the end connector 152 and two circular openings 146 either side of the central opening 144 for receiving the top portions 156b of the alignment pins 156. Figure 18A shows the same view as Figure 17 but with the end connector assembly 150 mounted on the service box casing 132. The support plate 154 is located on the outside of the service box casing 132 and the top side of the end connector 152 and the top portions 156b of the alignment pins 156 are received in the central and circular openings 144, 146 respectively. A nut 160 is threaded onto the end of the top portion 156b of each alignment pin 156 with a washer 162 located between the nut 160 and the inner surface of the service box casing 132. The diameter of each washer 162 is larger than the diameter of the circular openings 146 to prevent the support plate 154 falling off the service box casing 132 and the nuts 160 are tightened to prevent movement of the end connector assembly in the vertical direction.

Figure 18B shows the same view as Figure 18A with the nuts 160 and washers 162 removed. It can be seen that the diameter of the top portions 156b of the alignment pins 156 is smaller than the diameter of the circular openings 146, which allows the support plate 154 to move in any horizontal direction (i.e. any direction perpendicular to the connecting direction of the end connector 152) by a distance dictated by the diameter of the circular openings 146. The end connector 152 is thus configured as a “floating” connector, which helps the end connector 152 to successfully connect to the compartment connector 82 even if there is relatively high misalignment in the horizontal direction between the two connectors. Such misalignment may be due to relatively large manufacturing tolerances in the size and relative positions of the components of the battery assembly 100 and/or the battery compartment 80 and/or the bot 25.

While the end connector 152 and the compartment connector 82 described above are modular electrical connectors which combine a power connector module and signal connector module into a single unit, the service box 130 and the battery compartment 82 are not limited to comprising a modular end connector 152. Instead, the service box 130 could comprise an end power connector and a separate end signal connector and the battery compartment 80 could comprise a compartment power connector and a separate compartment signal connector. The separate end power connector and end signal connector could still be part of the same end connector assembly (i.e. mounted on the same support plate) or they may each be part of separate end connector assemblies which are separately configured to float in the same manner as the end connector 152 described above. Furthermore, the circular openings 146 in the service box casing 132 could have a different shape to limit the direction in which the end connector 152 can move relative to the service box casing. For example, the circular openings 146 may be rectangular or pill-shaped and sized to limit the end connector 152 to movement along one particular axis. In alternative examples, the compartment connector 82 may be configured to move relative to the battery compartment 80 in a direction perpendicular to the connecting direction of the compartment connector 82 instead of the end connector 152 using a similar arrangement to that described for the end connector 152.

Figure 19 shows a cable assembly 170 which is housed within the service box casing 132. The cable assembly 170 comprises electrical cables that electrically couple the intermediate connectors 140, 142 to the end connector 152. In particular, the cable assembly 170 comprises a positive cable 172 connecting the positive terminal of the intermediate power connector 140 to the positive terminal of the power connector module 152a of the end connector 152 and a negative cable 174 connecting the negative terminal of the intermediate power connector 140 to the negative terminal of the power connector module 152a of the end connector 152. The service box 130 further comprises a fuse 175 electrically coupled between the intermediate power connector 140 and the end connector 152 to provide overcurrent protection when the service box 130 is electrically coupled to the battery pack 110. In the illustrated example, the fuse 175 is connected between two portions of the positive cable 172 via bus bars 171. The cable assembly 170 further comprises signal cables 176 connecting the intermediate signal connector 142 to the signal connector module 152b of the end connector 152. Thus, when the service box 130 is attached and electrically coupled to the battery pack 110, electrical power and signals can be transmitted between the battery pack 110 and the bot 25 via the electrical components of the service box 130 (including the intermediate connectors 140, 142, the cable assembly 170, and the end connector 152).

The battery assembly 100 and battery compartment 80 of the bot 25 form part of a battery exchange system in which the battery assembly 100 within the battery compartment 80 of a bot 25 can be exchanged with another battery assembly 100, for example to exchange a depleted battery assembly 100 with a charged battery assembly 100. Battery exchanges could be performed manually, but for safety and efficiency reasons, battery exchanges are preferably carried out in an automated manner using a robotic arm. A robotic arm for use in the battery exchange system may comprise any suitable end effector for engaging the battery assembly 100 to allow the robotic arm to move the battery assembly 100 into and out of the battery compartment 80. For example, the battery assembly 100 may comprise a handle mounted on top of the battery assembly and the end effector may comprise a gripping assembly for releasably gripping the handle. Other example engagement mechanisms which can be used in the present system are described in United Kingdom patent application nos. GB2211853.3, GB2207553.5 and GB2216843.9, each of which is herein incorporated by reference.

T o minimise downtime of the bot 25 when performing a battery exchange operation, the robotic arm can be located on, over, or adjacent to the track structure 13 of the storage structure 1 such that the battery compartment 80 of the bot 25 is accessible to the robotic arm while the bot 25 remains on the track structure 13. The robotic arm may have any degrees of freedom necessary to allow the end effector to move a battery assembly 100 between the battery compartment 80 of a bot 25 and a drop-off location outside the battery compartment 80. When performing a battery exchange, the battery compartment of a bot 25 may be at a predetermined position with respect to the robotic arm 50, such that the robotic arm 50 can be configured to perform a set of predetermined movements to perform the battery exchange.

Figure 20 shows an example robotic arm in the form of a gantry robot 50A in which an end effector 51 is mounted on a gantry extending over a row of designated grid cells 14a of the track structure 13. The illustrated gantry robot 50A is configured to move the end effector 51 in the vertical direction and a first horizontal direction parallel to the row of designated grid cells 14a of the track structure 13 such that the end effector 51 can reach a bot 25 on any one of the designated grid cells 14a in the row and lower and raise the end effector to move a battery assembly 100 into and out of the battery compartment 80 of the bot 25. The gantry robot 50A could be further configured to move the end effector 51 in a second horizontal direction perpendicular to the first horizontal direction to allow the end effector to move above a plurality of rows of designated grid cells 14a.

Figure 21 shows an example robotic arm in the form of an articulated robot 50B located adjacent to the track structure 13 such that its end effector 51 can reach the battery compartment 80 of a bot 25 on a designated grid cell 14a or one of a plurality of designated grid cells 14a at the edge of the track structure 13. However, the articulated robot 50B could also be located on the track structure 13 itself, e.g. on a grid cell 14, to allow the end effector to reach the compartment of a bot 25 on a designated grid cell 14a or one of a plurality of designated grid cells 14a towards the middle of the track structure 13. The battery exchange system further comprises one or more battery stations 70 for storing battery assemblies 100 that have been removed from the battery compartment 80 of a bot 25 and for storing battery assemblies 100 to be inserted into an empty battery compartment 80 of a bot 25. Figure 22 shows an example battery station 70 comprising a plurality of bays 72. Each bay 72 is open to a top surface 71 of the battery station 70 such that each bay 72 can receive a battery assembly 100 in a downwards direction. The battery station 70 preferably comprises a charging system configured to charge a battery assembly 100 once it has been received in a bay 72. For example, each bay 72 may comprise an electrical connector similar or identical to the compartment connector 82 for connecting to the end connector 152 to electrically couple the battery assembly 100 to the charging system to allow the charging system to charge the battery assembly 100. The charging system may comprise a power supply, a charging controller and suitable circuitry configured to charge the battery assembly 100 using power from the power supply.

Each battery station 70 is located in the reachable vicinity of one or more robotic arms 50 so that each robotic arm 50 can move a battery assembly 100 between the battery compartment 80 of a bot 25 and the bays of the battery station 70. For example, a battery station 70 may be located in the region 52 marked in Figures 20 and 21 which is adjacent or near the track structure 13. A robotic arm 50 may be mounted on the battery station 70 itself to minimise the overall footprint of the robotic arm 50 and the battery station 70.

Figure 23 is a block diagram showing an example control system of the storage and retrieval system, including the battery exchange system. The positions of the bots 25 on the track structure 13, and their routes between positions on the track structure 13, are controlled by a central control system 180 comprising one or more controllers which are in wireless communication with each bot 25 on the track structure 13 using wireless transmitters and receivers and a suitable wireless communication technology such as 4G, 5G, Wi-Fi, etc. The one or more controllers of the central control system 180 receive data relating to which products are entering the storage and retrieval system and which products have been ordered by customers and uses this data to calculate routes for the bots 25 between target grid cells 14 to pick up and drop off particular storage containers 50 at particular locations. The one or more controllers of the central control system 180 command the bots 25 to move to target grid cells 14 via the calculated routes and pick up or drop off storage containers 50 at the target grid cells 14.

As mentioned above, the bot 25 comprises a bot controller 182 configured to control functions of the bot 25, such as operation of the driving assembly to move the bot 25 in a particular direction and for a particular distance, and operation of the lifting assembly 102 to lower and raise the holding frame 110. As mentioned above, the bot controller 182 is in wireless communication with the central control system 180 via a wireless transmitter and receiver mounted on the bot 25. The bot controller 182 is configured to receive commands from the central control system 180 (e.g. move to a particular grid cell 14 via a particular route and pick up or drop off a storage container 50) and send status updates to the central control system 180 (e.g. confirming the position of the bot 25 on the track structure 13 and the status of the lifting assembly 102).

When the battery assembly 100 is within the battery compartment and connected to the compartment connector 82, the bot controller 182 can communicate with the BMS 184 of the battery pack 110 via the signal connectors 122, 142 and cable assembly 170 of the service box 130. The BMS 184 can communicate the charge level of the battery pack 110 to the bot controller 182, for example, so that the bot controller 182 can determine when the bot 25 needs a battery exchange.

The robotic arm 50 comprises an arm controller 186 configured to control movement of the robotic arm 50 and end effector 51 and the charging system of the battery station 70 comprises a charging controller 188 configured to monitor and control various aspects of the charging system, e.g. monitor the occupancy of the bays 72 and the charge level of each battery assembly 100 in the occupied bays 72. The charging controller 188 is in communication with the arm controller 186 so that the charging controller 188 can command the robotic arm 50 to place a depleted battery assembly 100 removed from a bot 25 into a particular empty bay 72 and pick up a charged battery assembly 100 from a particular occupied bay 72 for inserting into a bot 25.

The above-described control system is just one example of how the control system of the storage and retrieval system may be arranged and other arrangements are possible by, for example, combining multiple controllers, adding further controllers, and adding or removing communication between the controllers.

A bot 25 may operate on the track structure 13 of the storage structure 1 until the charge level of its battery assembly 100 has depleted past a threshold charge level. Once this occurs, the bot 25 can communicate this to the central control system 180, which can then command the bot 25 to move to a designated grid cell 14a at which a robotic arm 50 can perform a battery exchange. Once the bot 25 has arrived at the designated grid cell 14a, the bot controller communicates this to the central control system 180, which can then command the robotic arm 50 to perform a battery exchange in accordance with commands from the charging controller 188 as described above.

The robotic arm 50 removes the depleted battery assembly 100 from the battery compartment 80 of the bot 25 and place into an empty bay 72 at the battery station 70 for charging. The robotic arm 50 then removes a charged battery assembly 100 (that is fully charged or at least has a greater charge level than the depleted battery assembly 100) and inserts it into the battery compartment 80 of the bot 25 so the bot 25 can continue operating on the track structure 13.

It will be appreciated that every time the battery assembly 100 is moved into or out of a battery compartment 80 or a battery station bay 72, the end connector 152 will connect to or disconnect from an external connector and will therefore experience wear and tear. In the storage and retrieval system described above, a battery assembly 100 may be exchanged many times every day. Electrical connectors are typically only rated for a particular number of mating cycles (connections and disconnections) and it is likely that the end connector 152 will reach the end of its life span before the battery pack 110 needs to be decommissioned due to deterioration of its battery cells.

The number of mating cycles undergone by the end connector 152 can be tracked, for example, by the central control system by recording in a database every time a battery exchange occurs for each particular battery assembly 100. Alternatively or in addition, referring back to Figure 19, the cable assembly 170 can further comprise a first electrical cable 178 electrically coupled between the signal connector module 152b and the positive terminal of the power connector module 152a, and a second electrical cable 179 electrically coupled between the signal connector module 152b and the negative terminal of the power connector module 152b such that the voltage between the positive and negative terminals of the power connector module 152a of the end connector 152 can be measured by the BMS or the bot controller 182 via the signal connector module 152b. From the voltage measurements and a known current, the resistance between the positive and negative terminals of the power connector module 152a can be determined and monitored. It is known that the resistance of an electrical connector increases as the number of mating cycles increases. Therefore, once the monitored resistance increases past a threshold resistance corresponding to a threshold number of mating cycles, the bot controller 182 may communicate to the central control system that its battery assembly 100 needs to be serviced. Once the end connector 152 has reached its rated number of mating cycles (or some other predetermined number of mating cycles), the battery assembly 100 can be serviced by detaching the service box casing 132 from the battery pack casing 112 (by unscrewing the screws 104) and pulling the service box 130 and battery pack 110 apart to disconnect the base connectors 120, 122 from the intermediate connectors 140, 142. The worn end connector 152 can then be replaced by a new end connector 152 and the original service box 130 can be reattached to the original battery pack 110. Alternatively, the original service box 130 can be completely replaced by another service box 130 that already has a new end connector 152.

The service box 130 thus acts as a sacrificial interface between the battery pack 100 and the bot 25 to minimise wear and tear of the base connectors 120, 122 of the battery pack 100 during the lifetime of the battery pack 110. In particular, the base connectors 120, 122 will only experience wear and tear whenever a service box 130 is coupled to and decoupled from the battery pack 110, rather every time the battery assembly 100 is connected to and disconnected from the bot 25 or the battery station. Furthermore, the service box 130 is electrically “dead” once it is decoupled from the battery pack 110 and therefore replacing the end connector 152 does not require workers who need to be trained to work with batteries. Therefore, the end connector 152 of the battery assembly 100 can be replaced quickly, efficiently, and cost-effectively by minimising the need to replace the base connectors 120, 122 of the battery pack 110 itself.

The above-described arrangement of the service box 130 and battery pack 110 also provides advantages relating to the centre of gravity of the bot 25. It is generally preferable for the bot 25 to have as low a centre of gravity as possible for stability reasons, e.g. to avoid the bot 25 toppling over during acceleration and deceleration. The battery pack 110 is generally one of the heaviest components in the bot 25 and therefore the vertical position of the battery pack 110 within the bot 25 will have a relatively large effect on the location of the centre of gravity of the bot 25. By arranging and orientating the base connectors 120, 122, the intermediate connectors 140, 142 and the end connector 152 such that the service box 130 can be attached to a lateral side of the battery pack 110 while still providing a downward facing end connector 152 for connecting to the compartment connector 82, the vertical position of the battery pack 110 within the bot 25 is substantially the same as it would have been if the battery pack 110 was not provided with the service box 130. The arrangement described above therefore has a minimal effect on the centre of gravity of the bot 25 compared to an arrangement where, for example, the service box 130 is attached to the bottom of the battery pack 110. More generally, by providing the battery pack 110 with the service box 130, the end connector 152 of the battery assembly 100 can be positioned and orientated in any desired direction, regardless of the position and orientation of the base connectors 120, 122 of the battery pack 110, which may provide advantage such as the advantage relating to centre of gravity described above.

The present invention is not limited to the precise forms described above and various modifications and variations will be apparent to the skilled person.

For example, the battery assembly 100 is not limited to being used with the bot 25 of the storage and retrieval system described above. The battery assembly 100 could be used in any battery exchange system with a battery-powered device that comprises a battery compartment for removably receiving and electrically coupling to the battery assembly 100. Furthermore, the battery assembly 100 is not limited to being used in a particular orientation; the service box 130 is not limited to being attached to any particular side of the battery pack 110 (provided the base connectors 120, 122 and the intermediate connectors 140, 142 are arranged accordingly); and the end connector is not limited to being orientated for connection with an external device in any particular direction. In other words, the arrangement between the battery pack 110 and the service box 130 and their respective electrical connectors can be modified from the above-described example to suit the particular battery-powered device of the battery exchange system. For example, the battery compartment 80 may be configured to receive the battery assembly 100 in a horizontal direction and the compartment connector 82 may also be configured to connect in a horizontal direction, in which case the end connector 152 may also be arranged and configured to connect in a horizontal direction, rather than a vertical direction.

In addition, the battery pack 110 and the service box 130 do not need to be provided with both power and signal connectors. Only one connector or type of connector may be provided on each of the battery pack 110 and the service box 130, e.g. just a power connector, or more than two connectors or types of connectors may be provided on each of the battery pack 110 and the service box 130 as necessary.

In addition to the end connector 152 being a floating connector, the base connectors 120, 122 and/or the intermediate connectors 140, 142 could also be configured as floating connectors in a similar manner (i.e. they could be configured to move relative to the battery pack casing 112 or the service box casing 132 in a direction perpendicular to their connection directions up to a predetermined distance) to allow for manufacturing tolerances in the construction of the battery pack 110 and the service box 130.

Claims

1. A battery assembly comprising: a battery pack comprising an outer battery pack casing and a base electrical connector; and a service box comprising an outer service box casing, an intermediate electrical connector and an end electrical connector, wherein the intermediate electrical connector is electrically coupled to the end electrical connector, and the intermediate electrical connector and the base electrical connector are configured to reversibly connect to each other; wherein the battery pack casing is releasably attached to the service box casing to form a single unit in which the base electrical connector is connected to the intermediate electrical connector, and the end electrical connector is externally exposed to allow the battery pack to electrically couple to an external device via the service box; wherein the end electrical connector is mounted to the service box casing such that the end electrical connector can move relative to the service box casing in a direction substantially perpendicular to the connecting direction of the end electrical connector.

2. The battery assembly according to claim 1 , wherein the base electrical connector, the intermediate electrical connector and the end electrical connector are power connectors configured to allow power to be transferred from the battery pack to an external device via the service box and/or vice versa.

3. The battery assembly according to claim 2, wherein the service box comprises a fuse coupled between the intermediate electrical connector and end electrical connector.

4. The battery assembly according to any one of the preceding claims, wherein the connecting direction of the end electrical connector is different to the connecting direction of the intermediate electrical connector.

5. The battery assembly according to any one of the preceding claims, wherein the service box casing is releasably attached to the battery pack casing by one or more fasteners.

6. The battery assembly according to any one of the preceding claims, wherein the battery pack comprises a guide feature configured to cooperate with a corresponding guide feature of the service box such that the base electrical connector is aligned for connection with the intermediate electrical connector and the battery pack casing is aligned for attachment to the service box casing.

7. The battery assembly according to any one of the preceding claims, wherein the end electrical connector comprises at least one alignment member for cooperating with at least one corresponding alignment feature of an external electrical connector to align the end electrical connector with the external electrical connector to allow the end electrical connector to connect to the external electrical connector.

8. The battery assembly according to claim 7, wherein the at least one alignment member of the end electrical connector comprises a protrusion or a recess extending in a direction parallel to the connecting direction of the end electrical connector.

9. The battery assembly according to any one of the preceding claims, wherein the base electrical connector is mounted on the battery pack casing such that the base electrical connector can move relative to the battery pack casing in a direction substantially perpendicular to the connecting direction of the base electrical connector.

10. The battery assembly according to any one of the preceding claims, wherein the intermediate electrical connector is mounted on the service box casing such that the intermediate electrical connector can move relative to the service box casing in a direction substantially perpendicular to the connecting direction of the intermediate electrical connector.

11. The battery assembly according to any one of the preceding claims, wherein the service box further comprises a cable assembly comprising one or more electrical cables configured to electrical couple the intermediate electrical connector to the end electrical connector.

12. The battery assembly according to any one of the preceding claims, wherein: the battery pack comprises a plurality of base electrical connectors; the service box comprises a plurality of intermediate electrical connectors and a plurality of end electrical connectors, wherein each intermediate electrical connector is electrically coupled to a respective end electrical connector, and each intermediate electrical connector is configured to reversibly connect to a respective base electrical connector; wherein the battery pack casing is releasably attached to the service box to form a single unit in which the each base electrical connector is connected to a respective intermediate electrical connector, and each end electrical connector is externally exposed to allow the battery pack to electrically couple to an external device via the service box.

13. The battery assembly according to claim 12, wherein at least one of the plurality of base electrical connectors is a power connector, at least one of the plurality of intermediate electrical connectors is a power connector and at least one of the plurality of end electrical connectors is a power connector to allow power to be transferred from the battery pack to an external device via the service box and/or vice versa.

14. The battery assembly according to claim 12 or claim 13, wherein the battery pack further comprises a battery management system and wherein at least one of the plurality of base electrical connectors is a base signal connector electrically coupled to the battery management system, at least one of the plurality of intermediate electrical connectors is a signal connector, and at least one of the plurality of end electrical connectors is a signal connector to allow signals to be transferred from the battery management system to an external device via the service box and/or vice versa.

15. A battery exchange system comprising the battery assembly as defined in any one of the preceding claims and an external device comprising a battery compartment configured to removably receive the battery assembly, wherein the battery compartment comprises a compartment electrical connector configured to reversibly connect to the end electrical connector of the battery assembly to electrically couple the battery assembly to the external device.

16. The battery exchange system according to claim 15, further comprising a robotic arm configured to move the battery assembly into and out of the battery compartment.

17. The battery exchange system according to claim 16, further comprising a battery station comprising one or more bays configured to removably receive the battery assembly and a charging system for charging the battery assembly, wherein each bay comprises an electrical connector configured to reversibly connect to the end connector of the battery assembly to electrically couple the battery assembly to the charging system, and the robotic arm is further configured to move the battery assembly into and out of the bays and move the battery assembly between the battery compartment of the external device and the bays of the battery station.

18. The battery exchange system according to any one of claims 15 to 17, wherein the battery compartment is configured to receive the battery assembly in a downwards direction and the service box is releasably attached to a lateral side the battery pack.

19. The battery exchange system according to any one of claims 15 to 18, wherein the battery assembly has an outer battery assembly casing defined by the battery pack casing and the service box casing and battery assembly, and one or more locating members mounted on the battery assembly casing, wherein the locating members are configured to allow the battery assembly to self-locate into the battery compartment when the battery assembly is being moved into the battery compartment.

20. The battery exchange system according to any one of claims 15 to 19, wherein the external device is a load handling device for lifting and moving containers arranged in stacks in a storage structure, the storage structure comprising a track structure, the track structure comprising a first set of tracks and a second set of tracks, the first set of tracks extending in a first direction and the second set of tracks extending in a second direction, the second direction being substantially perpendicular to the first direction, to form a grid pattern defining a plurality of grid cells above the stacks of containers, the load handling device comprising: a driving assembly configured to move the load handling device on the track structure; a container-holding device configured to releasably hold a container from above; and a lifting mechanism configured to raise and lower the container-holding device.

21 . A storage and retrieval system comprising: a storage structure comprising: a track structure, the track structure comprising a first set of tracks and a second set of tracks, the first set of tracks extending in a first direction and the second set of tracks extending in a second direction, the second direction being substantially perpendicular to the first direction, to form a grid pattern defining a plurality of grid cells; and a plurality of upright members configured to support the track structure from below to define a storage area below the track structure for storing a plurality of stacks of containers below each grid cell; and wherein the storage and retrieval system further comprises the battery exchange system as defined in claim 20.

22. A method of servicing the battery assembly defined in any one of claims 1 to 14, wherein the service box is a first service box, and the method comprises the steps of: (i) detaching the first service box casing from the battery pack casing;

(ii) separating the first service box from the battery pack to disconnect the base electrical connector from the intermediate electrical connector;

(iii) coupling the second service box and the battery pack to connect the base electrical connector to the intermediate electrical connector of the second service box; and

23. A method of servicing the battery assembly defined in any one of claims 1 to 14, comprising the steps of:

(i) detaching the service box casing from the battery pack casing;

(iii) replacing or fixing at least one component of the service box;

(v) attaching the service box casing to the battery pack casing.

24. The method according to claim 23, wherein the at least one component in step (iii) includes the end electrical connector.