GB2538932A

GB2538932A - Battery module and casing

Info

Publication number: GB2538932A
Application number: GB1501235.4A
Authority: GB
Inventors: Mifsud Bernard
Original assignee: BYTEC HEALTHCARE Ltd
Current assignee: BYTEC HEALTHCARE Ltd
Priority date: 2015-01-26
Filing date: 2015-01-26
Publication date: 2016-12-07
Anticipated expiration: 2035-01-26
Also published as: GB201501235D0; GB2538932B; WO2016120584A1

Abstract

A battery casing 1 for containing an electrical battery cell and associated circuitry comprises first and second parts 4, 5 which connect together, wherein the peripheries of the parts are formed with a tongue and groove connection between which is located a seal 21. When the parts 4, 5 are connected, the seal 21 is held securely in place to form a watertight seal preventing the ingress of liquid into the encasement interior. A battery module comprising a rechargeable battery cell enclosed within this battery casing is also claimed. In a further aspect, the waterproof battery module includes docking connection members (41, fig 2) which are located within an interior compartment 17 within the casing 1 and resiliently biased (43, fig 2) towards an exterior opening, the docking connection members having a seal (45, fig 2) to prevent ingress of liquid into the interior compartment. A docking station, and arrangement to prevent electrical connection between the battery module and an incompatible device are also claimed.

Description

Battery Module and Casing

Field of the Invention

This invention relates to a rechargeable battery module and a casing for such a battery.

Background of the Invention

Electrical batteries are used in many applications. One important application is in the medical field. For example, it is known to provide a wheeled trolley with a platform on which to support a display for entertainment or for other medical equipment supported on the platform. The trolley includes a docking station for receiving one or more rechargeable batteries which provide portable power for equipment supported thereon In a hospital or similar environment, hygiene is of upmost importance in relation to all forms of equipment in order to minimise contamination and infection. For this reason there is a trend towards producing equipment that can be easily and conveniently cleaned or washed. Rechargeable batteries by their nature tend to be swapped on a regular basis and therefore present an obvious risk for contamination. However, exposing batteries to liquids such as water or disinfectants is generally discouraged. It can be hazardous, particularly if liquid were to ingress within the battery casing and affect the internal battery cell and associated circuitry.

Liquids may cause corrosion of the internal cell and circuitry and/or lead to the formation of combustible gas. This is particularly the case with Lithium battery cells which are becoming highly popular due to their relatively small size.

Further, batteries when removed from their docking station can be damaged if the exposed connector terminals are shorted, e.g. by liquid or by a conductive element or surface, whether done accidentally or deliberately.

It is therefore an aim to provide an improved battery and battery casing.

Summary of the Invention

A first aspect of the invention provides a battery casing for containing an electrical battery cell and associated circuitry, the casing being comprised of first and second parts which connect together and wherein the peripheries of the parts are formed with a tongue and groove connection between which is located a seal which when the parts are connected is held securely in place to form a watertight seal preventing the ingress of liquid into the encasement interior.

The first and second parts may be formed separate from one another and the groove and tongue parts may extend continuously around their entire periphery.

One of the parts may be formed with two handle insert portions for receiving respective ends of a carrying handle, each handle insert portion being provided by a double wall section which defines an interior space within which an end of the handle is received for connection to one of the walls, and wherein a sealing insert is located within the interior space.

The casing may further comprise within the periphery of one of the parts a compartment housing one or more connecting pins which is or are biased to protrude to the exterior of the compartment and which in use is or are used to releasably connect the casing to an external docking station or charger, the or each pin being surrounded within the compartment by a sealing member for preventing the ingress of liquid into the compartment. The compartment may be formed by an interior wall located within the part and which mates with a surface on the other part using a tongue and groove connection with a seal being located between the mating connection. The or each sealing member may be an 0-ring.

The or each pin may be mounted on a spring-like member mounted to a base of the watertight compartment which biases the pin to protrude outwardly.

The battery casing may further comprise one or more apertures in one of the parts filled or covered with a sealing material providing a point-of-weakness in the event of a build-up of pressure within the battery casing.

The sealing material may be transparent or translucent.

The battery casing may further comprise a plurality of apertures adjacent to which are located respective battery input and output terminals for connection to corresponding terminals of a docking station or charger.

Each battery terminal may be substantially planar and adhered to an interior surface of the casing in a watertight manner so that the connector is recessed.

Any one or more of the seal, sealing insert, sealing member or sealing material may be silicon-based.

A second aspect of the invention provides a rechargeable battery module comprising an electrical battery cell enclosed within a battery casing according to any preceding definition.

The module may further comprise one or more light emitting elements, e.g. LEDs, each located adjacent a corresponding one of the sealed apertures.

The battery module may further comprise a control module configured automatically to isolate the electrical cell from discharging energy to an output terminal until a predetermined condition is met.

The control module may be configured to isolate the electrical cell until a predetermined control terminal receives a predetermined signal or voltage.

The electrical cell may be isolated until a predetermined control terminal, which is normally held at a predetermined non-zero voltage, is pulled low to a zero voltage or thereabouts.

The control module may be configured to isolate the electrical cell until a button or switch is manually operated by user action.

The control module may be configured to isolate the electrical cell until the button or switch is manually operated for a minimum time period.

The button or switch is preferably capacitive.

A third aspect of the invention provides a rechargeable battery module comprising an electrical battery cell housed within a waterproof casing with a plurality of terminals exposed to the exterior of the casing for connection to an external charger or docking station, the casing comprising first and second parts joined using a tongue and groove interface between which is located a seal and within which is provided an internal wall defining an interior compartment which houses one or more docking connection members resiliently biased towards an exterior opening to enable detachable connection with an external charger or docking station, the or each docking connection member being surrounded within the interior compartment by a seal to prevent the ingress of a liquid within the compartment.

The battery module may further comprise a control module associated with the battery cell and which is configured to isolate the cell from discharging electrical energy through an output terminal until a control connector which is held at a non-zero voltage is grounded, e.g. due to the battery module being connected to a charger or docking station.

The control module may be further be arranged to isolate the cell until a power button or switch is manually operated whilst the control connector is grounded.

The control module may be further connected to a display means comprising one or more light emitting units each positioned adjacent a corresponding aperture in the casing which is filled or covered with a transparent or translucent sealing material.

A fourth aspect of the invention provides a docking station for the rechargeable battery module according to any of preceding definition comprising a control terminal configured to contact a control terminal of the battery module and connect it to a ground (zero) voltage or thereabouts, and one or more other terminals for connection to corresponding terminals of the battery module for receiving electrical energy from the cell.

A fifth aspect of the invention provides a rechargeable battery module comprising an electrical battery cell housed within a waterproof casing with a plurality of terminals being accessible to the exterior for receiving a charging current from a source and/or for discharging electrical energy to a connected device, wherein the battery module further comprises a control module configured automatically to isolate the electrical cell from discharging energy to an output terminal until predetermined conditions associated with a different, control terminal, are met.

The control terminal may be held at a non-zero (high) voltage when not connected and is effective to cause the control module to isolate the cell from discharging electrical energy to the output terminal until the control terminal is pulled to a predetermined low or zero voltage, e.g. due to the battery module being connected to a charger or docking station.

The control module may be further arranged to isolate the cell until a power button or switch is manually operated whilst the control terminal is pulled low.

Brief Description of the Drawings

The invention will now be described, by way of non-limiting example, with reference to the accompanying drawings, in which: Figure 1 is an exploded perspective view of a battery module casing in accordance with one aspect of the invention; Figure 2 is a close-up sectional view of part of the casing shown in Figure 1; Figure 3 is a close-up sectional view of a connector clip of the casing shown in Figure 1; Figure 4 is an exploded perspective view of one part of the casing shown in Figure 1, from a reverse side; Figure 5 is a perspective view of a medical trolley having a plurality of battery modules connected thereto via docking station(s); Figure 6 is a perspective view of the docking station hidden from view in Figure 5; Figure 7 is a perspective view of electrical connector terminals of the docking station of Figure 6; Figure 8 is a perspective view of electrical connector terminals of a battery module for connection to the docking station of Figure 6; and Figure 9 is a circuit schematic of a battery module and docking station, including functional modules.

Detailed Description of Preferred Embodiment(s)

Referring to Figure 1 there is shown a battery pack casing 1 for enclosing a battery cell (not shown) to provide a rechargeable battery pack for use in medical applications where it may be desirable to frequently wash the battery pack with liquid.

Figure 5 shows a medical trolley 61 on which electronic medical equipment (or entertainment equipment for use in a medical environment) may be mounted and powered by a battery pack 63. In this case, first and second battery packs 63 are shown mounted on the stem of the trolley 61; one battery pack 63 is connected to a docking station (not clearly shown in Figure 5) to provide power to the electronic equipment and the other is a replacement battery supported on the opposite side for manual replacement into the docking station when required.

Alternatively, two docking stations may be provided so that batteries can be 'hot swapped' automatically when the charge on one battery is depleted.

Figure 6a shows an example docking station 65 which comprises an elongate unit having, at a lower end, a lower dock support 67 on which one end of the battery pack 63 is located in use and, at an upper end, a dock connector 69 into which the other end of the battery pack is releasably secured into position. In order to connect a battery pack 63 to the docking station 65, the lower end of the battery pack 63 is first located over a protruding part of the lower dock support 67 and then the upper part is rotated towards the dock connector 69 where it is secured it in place. Figure 6b shows the battery pack 63 when secured to the docking station 65.

When a battery pack 63 is connected to the docking station 65, electrical energy is discharged into internal circuitry of the trolley 61 which provides the necessary connections to the supported electronic equipment. Discharge is by means of a series of dome-like metallic electrical connectors 71 which connect to correspondingly-located terminals 72 of the battery pack 63 (see Figures 7 and 8.) The battery pack 63 can be charged via the docking station 65 if it has a source of mains power; alternatively, the battery pack 63 can be charged using a separate charging unit.

Returning to Figure 1, a first embodiment relates to the waterproof casing 1 for such a battery pack 63. It will be appreciated that a completed battery pack 63 will include at least a battery cell and some associated control and display circuitry which is housed within the casing 1.

The casing 1 comprises a first, lower part 3 and a second, upper part 5.

The first part 3 comprises a generally rectangular base wall 7, two upstanding lateral walls 9, an end wall 11 and, opposite to the end wall, a top, connecting-end wall 15 with a fork-like shape. The end wall 11 includes an indented socket 13 which locates over the lower dock support 67 shown in Figure 6a. The top wall 15 provides at the other end a docking socket 39 (see Figure 2) which fits around the dock connector 69 shown in Figure 6a. The walls 9, 11, 15 together define a perimeter wall which is formed with a continuous groove or channel 4 extending towards the base wall 7. The groove or channel 4 is U-shaped in cross-section.

A further, interior, wall 16 extends below the top wall 15 and has a U-shape profile. It defines within its interior one or more connector compartments 17 which, as will be explained below, hold part of a connector mechanism (not shown) which secures the battery pack to the dock connector 69. The interior wall 16 likewise has a groove or channel 4 extending generally towards the base wall 7.

On each lateral wall 9 of the first part 3 is provided a housing 23 for connecting a respective end of a carrying handle (not shown). Each housing 23 comprises a wall section that protrudes outwardly from the lateral wall to provide a double-skin section with the gap in-between being shaped to receive a handle end that clips into a receiving hole.

The second part 5 of the battery case 1 comprises a flatter, lid-like face that is shaped to substantially match the upper edge of the first part 3 so that it can be connected to it. The lower face of said second part 5 has a continuous tongue portion 6 projecting downwardly in the shown orientation. The profile of the tongue portion 6 is such that it matches, and can be received within, the groove 4 of the first part.

A number of holes 19 are formed within the second part; when a battery cell is connected within the casing, a set of metallic connector terminals 72 (shown in Figure 8) are adhered to the interior side of these holes 19 so that the dome-like electrodes 71 shown in Figures 6 and 7 can make contact when the battery pack 63 is connected to the docking station 65. The connector terminals 72 are adhered behind the holes 19 within the body of the casing 1 using a silicon watertight sealant to prevent the ingress of water through these holes. The connector terminals 72 have a substantially flat profile and because they are recessed slightly from the outer surface of the casing 1, the terminals cannot be accidentally shorted if placed face down on e.g. a metallic surface.

A line or layer of a flexible watertight sealing material 21 is provided between the first and second parts 3, 5. The sealing material is preferably a flexible, silicon based material. This is referred to hereafter as the 'main seal' 21. The profile of the main seal 21 substantially matches that of the groove 4 on the upper walls of the first part 3, as shown in Figure 1. The first and second parts 3, 5 are joined together (with the battery cell and associated circuitry contained inside) so that the main seal 21 is firmly sandwiched between the tongue 6 and the groove 4 with the seal located mainly within the groove. The two casing parts 3, 5 are then secured together with clips 23 and the parts screwed firmly together using screws provided in the threaded holes 25 shown. One such clip is shown in Figure 3 and it will be seen that a layer of silicon is embedded within a clip groove, away from the actual clip itself, to provide further waterproofing.

The provision of the main seal 21 prevents the ingress of fluid into the interior of the casing 1, thereby protecting the battery cell and associated circuitry. This enables the battery pack to be washed or cleaned. Typically, this may be performed by holding the handle (not shown) and dipping the battery pack base-first into a solution of liquid disinfectant, something which is currently not considered in the art.

The connector compartment 17 is further sealed by virtue of the main seal 21 extending also around the U-shaped interior wall 16 of said compartment. This means that connector compartment 17 has two layers of sealing. This is particularly advantageous because in the case where the battery pack is dipped into disinfectant liquid base-first (with the user holding the handle) some liquid may remain in the docking socket 39 making this area otherwise vulnerable.

Referring to Figure 2, which shows a cross-section of the connector compartment 17, it will be seen that it is divided into two separate portions, each housing a coil-spring 43. On the end of each spring 43 is mounted a connector pin 41 a top part of which emerges into the docking socket 39 through a hole. Each coil-spring 43 biases the connector pin 41 towards the top wall 15. Referring back to Figure 6, the battery pack 63 connects to the dock connector 69 by means of the connector pins 41 clipping inside corresponding sockets (not shown) in the dock connector. As the battery pack 63 is moved into the connected position, the connector pins 41 are forced downwards against the biasing until the pins return upwards into the connected position. The term 'pin' or 'pins' as used herein is intended to cover obvious variations or alternatives.

Two 0-ring type watertight seals 45 are provided within each portion of the connector compartment 17, adjacent a respective hole and surrounding the connector pin 41, so that a watertight seal is formed around each connector pin 41 to further prevent liquid from entering the connector compartment 17. Thus, the connector compartment 17 is further protected against the ingress of liquid.

Referring now to Figure 4, the first casing part 3 is shown from the reverse side. A fascia recess 29 is formed within the exterior of the base wall 7 and comprises a number of apertures 31. Each aperture 31 is filled with a watertight sealant 33 which is either transparent or translucent when set. Finally, a fascia label 35 is adhered into the recess, the label including transparent or translucent parts corresponding to the position of the sealed apertures 31. On the interior side of the first casing part 3 can be mounted a circuit board (not shown) having a plurality of LEDs or other light emitting elements corresponding to the apertures 31. The LEDs may serve various purposes; one may be for indicating power on/off and others (e.g. the line of ten identical apertures) a bar graph indicating level of charge remaining in the battery cell. By sealing the apertures 31 individually with watertight sealant 33, water is prevented from entering the interior of the casing 1. Due to the fact that the sealant is transparent or translucent, light from the LEDs is visible from the exterior. Furthermore, each of the sealant portions 33 (by virtue of the smaller area of sealant used for each) represents an area of weakness which means that should any fault arise internally causing a build-up of pressure within the casing 1 (e.g. a thermal runaway condition) then one of the sealant portions 33 will fracture first which will be immediately visible due to distortion of the label 35 and this will also permit venting to avoid pressure building up to a dangerous level.

Figure 7 shows the connector terminals 71 on the docking station 65. Figure 8 shows the corresponding connector terminals 72 on the battery casing 1.

A second embodiment provides a battery pack 63, for example for use with the trolley shown in Figure 5. The battery pack 63 comprises the first embodiment battery casing 1 within which is located a battery cell (e.g. a Lithium Ion cell) connected to control circuitry for handling power on/off, charging and discharging control, and the control of a set of LEDs mounted on a circuit board that is positioned adjacent the sealed holes 31 referred to above. The battery casing 1 comprises the above described first and second parts 3, 5 connected together with the watertight main seal 21 and which can therefore be washed, e.g. by wiping or by dipping in a solution of disinfecting liquid. The battery pack 63 includes a carrying handle (not shown) to allow convenient carriage of the pack and dipping of the pack into a solution of cleaning liquid.

A further advantageous feature of the battery pack 63 is the recessed electrical connector terminals 72 which have a substantially flat profile and because they are recessed slightly from the outer surface of the casing 1 cannot be accidentally shorted if placed face down on e.g. a metallic surface.

A further advantageous feature of the battery pack 63 is the provision of a control module which isolates the battery cell from the external terminals 72 until one or more predetermined conditions are met. In one example, the battery cell is isolated until a specific control connector terminal 83 is connected to ground.

Figure 9 shows a schematic circuit diagram of control circuitry within the battery pack 63. The rechargeable battery cell, e.g. a Lithium Ion cell, is indicated by reference numeral 101. When charging and discharging, the battery cell 101 is required to be connected to four terminals 81 referred to as Vbat. These Vbat terminals 81 are arranged to make contact with four corresponding Vbat terminals 91 of the docking station 65. A microprocessor 97 is configured to control an isolation switch 01 103 which, as the name suggests, isolates the battery cell 101 from the external Vbat terminals 81 when Q1 is switched off. A further control connector Dock_Detect 83 provides a control input to the microprocessor 97. The Dock_Detect 83 connector is normally held at a non-zero (Hi) voltage by virtue of resistor 99 but will be pulled low when Dock_Detect is connected to the docking station 65; this is because the corresponding terminal 93 of the docking station 65 is connected to ground. When Dock_Detect 83 is pulled low, the microprocessor 97 is configured to turn on the switch Q1 which connects the battery cell 101 to the Vbat terminal 81.

This isolation system requires the battery pack 63 to be connected to the docking station 65 in order to permit charging and discharge. This prevents accidental damage occurring to the battery cell 101, e.g. by shorting terminals when the battery pack 63 is not connected to the docking station 65 and permits cleaning using liquid.

Additionally, or alternatively, the control circuitry may require a power-on button or switch to be operated in order to switch Q1 103 on. This is preferably a capacitive switch requiring human contact. For example, the microprocessor 97 may only tum Q1 103 on when Dock_Detect 83 is pulled low and the power-on button is operated. The microprocessor 97 may require the power-on button to be operated for a predetermined minimum time period of, say, two or more seconds before Q1 103 is switched on. This further prevents the battery cell 101 from accidental damage or discharge, even if Dock_Detect 83 is somehow pulled low.

A further embodiment provides a method of constructing a battery pack, comprising providing a battery casing 1 as described above, formed of first and second parts 3, 5, providing a main seal 21 located between the peripheral connections which are sandwiched between the tongue and groove portions 6, 4 to retain a battery cell and associated circuitry therewithin.

It will be appreciated that the above described embodiments are purely illustrative and are not limiting on the scope of the invention. Other variations and modifications will be apparent to persons skilled in the art upon reading the present application.

Moreover, the disclosure of the present application should be understood to include any novel features or any novel combination of features either explicitly or implicitly disclosed herein or any generalization thereof and during the prosecution of the present application or of any application derived therefrom, new claims may be formulated to cover any such features and/or combination of such features.

Claims

Claims 1. A battery casing for containing an electrical battery cell and associated circuitry, the casing being comprised of first and second parts which connect together and wherein the peripheries of the parts are formed with a tongue and groove connection between which is located a seal which when the parts are connected is held securely in place to form a watertight seal preventing the ingress of liquid into the encasement interior.
2. A battery casing according to claim 1, wherein the first and second parts are formed separate from one another and the groove and tongue parts extend continuously around their entire periphery.
3. A battery casing according to claim 1 or claim 2, wherein one of the parts is formed with two handle insert portions for receiving respective ends of a carrying handle, each handle insert portion being provided by a double wall section which defines an interior space within which an end of the handle is received for connection to one of the walls, and wherein a sealing insert is located within the interior space.
4. A battery casing according to any preceding claim, further comprising within the periphery of one of the parts a compartment housing one or more connecting pins which is or are biased to protrude to the exterior of the compartment and which in use is or are used to releasably connect the casing to an external docking station or charger, the or each pin being surrounded within the compartment by a sealing member for preventing the ingress of liquid into the compartment.
5. A battery casing according to claim 4, wherein the compartment is formed by an interior wall located within the part and which mates with a surface on the other part using a tongue and groove connection with a seal being located between the mating connection.
6. A battery casing according to claim 4 or claim 5, wherein the or each sealing member is an 0-ring.
7. A battery casing according to any one of claims 4 to 6, wherein the or each pin is mounted on a spring-like member mounted to a base of the watertight compartment which biases the pin to protrude outwardly.
8. A battery casing according to any preceding claim, further comprising one or more apertures in one of the parts filled or covered with a sealing material providing a point-ofweakness in the event of a build-up of pressure within the battery casing.
9. A battery casing according to claim 8, wherein the sealing material is transparent or translucent.
10. A battery casing according to any preceding claim, further comprising a plurality of apertures adjacent to which are located respective battery input and output terminals for connection to corresponding terminals of a docking station or charger.
11. A battery casing according to claim 10, wherein each battery terminal is substantially planar and is adhered to an interior surface of the casing in a watertight manner so that the connector is recessed.
12. A battery casing according to any preceding claim, wherein any one or more of the seal, sealing insert, sealing member or sealing material is silicon-based.
13. A rechargeable battery module comprising an electrical battery cell enclosed within a battery casing according to any preceding claim.
14. A rechargeable battery module according to claim 13 when dependent on claim 9, further comprising one or more light emitting elements, e.g. LEDs, each located adjacent a corresponding one of the sealed apertures.
15. A rechargeable battery module according to claim 13 or claim 14 when dependent on claim 11 wherein the battery further comprises a control module configured automatically to isolate the electrical cell from discharging energy to an output terminal until a predetermined condition is met.
16. A rechargeable battery module according to claim 15, wherein the control module is configured to isolate the electrical cell until a predetermined control terminal receives a predetermined signal or voltage.
17. A rechargeable battery according to claim 16, wherein the electrical cell is isolated until a predetermined control terminal, which is normally held at a predetermined non-zero voltage, is pulled low to a zero voltage or thereabouts.
18. A rechargeable battery module according to any one of claims 15 to 17, wherein the control module is configured to isolate the electrical cell until a button or switch is manually operated by user action.
19. A rechargeable battery module according to claim 18, wherein the control module is configured to isolate the electrical cell until the button or switch is manually operated for a minimum time period.
20. A rechargeable battery module according to claim 18 or claim 19, wherein the button or switch is capacitive. 15
21. A rechargeable battery module comprising an electrical battery cell housed within a waterproof casing with a plurality of terminals exposed to the exterior of the casing for connection to an external charger or docking station, the casing comprising first and second parts joined using a tongue and groove interface between which is located a seal and within which is provided an internal wall defining an interior compartment which houses one or more docking connection members resiliently biased towards an exterior opening to enable detachable connection with an external charger or docking station, the or each docking connection member being surrounded within the interior compartment by a seal to prevent the ingress of a liquid within the compartment.
22. A rechargeable battery module according to claim 21, further comprising a control module associated with the battery cell and which is configured to isolate the cell from discharging electrical energy through an output terminal until a control connector which is held at a non-zero voltage is grounded, e.g. due to the battery module being connected to a charger or docking station.
23. A rechargeable battery module according to claim 22, wherein the control module is further arranged to isolate the cell until a power button or switch is manually operated whilst the control connector is grounded.
24. A rechargeable battery module according to any of claims 21 to 23, wherein the control module is further connected to a display means comprising one or more light emitting units each positioned adjacent a corresponding aperture in the casing which is filled or covered with a transparent or translucent sealing material.
25. A docking station for the rechargeable battery module according to any of claims 13 to 24 comprising a control terminal configured to contact a control terminal of the battery module and connect it to a ground (zero) voltage or thereabouts, and one or more other terminals for connection to corresponding terminals of the battery module for receiving electrical energy from the cell.
26. A rechargeable battery module comprising an electrical battery cell housed within a waterproof casing with a plurality of terminals being accessible to the exterior for receiving a charging current from a source and/or for discharging electrical energy to a connected device, wherein the battery module further comprises a control module configured automatically to isolate the electrical cell from discharging energy to an output terminal until predetermined conditions associated with a different, control terminal, are met.
27. A rechargeable battery module according to claim 26, wherein the control terminal is held at a non-zero (high) voltage when not connected and is effective to cause the control module to isolate the cell from discharging electrical energy to the output terminal until the control terminal is pulled to a predetermined low or zero voltage, e.g. due to the battery module being connected to a charger or docking station.
28. A rechargeable battery module according to claim 27, wherein the control module is further arranged to isolate the cell until a power button or switch is manually operated whilst the control terminal is pulled low.