GB2275817A - Battery control device incorporating timer and switch - Google Patents

Abstract

A device that regulates the times or time periods at which a battery may function to supply current to an external electrical or electronic device that places a load on the battery comprises means to supply control signals to a switch, the control algorithm using time as input information, the physical size of the device being such as to allow the device combined with the battery to be inserted into the battery bay of the load, and may be internal or external of the battery. If external to the battery the device fits snugly around the battery packaging.

Description

TIMER BATTERY SUGARY This invention relates to a device that regulates the times or time periods at which a battery may function to supply current to an external electrical or electronic device that places a load on the battery. The battery regulating device may either be internal to the battery so that the battery contact(s) are controlled, or it may be external to the battery and be interposed electrically between one or more of the contacts of the battery and the contact(s) of an external load (ie that uses the battery) so that the device may act as a selective conductor between the battery and load contacts to allow regulation of the time, perhaps programmably, at which the effective battery-device external contacts may supply current to the load device. Various methods for deciding the time at which the battery may be enabled to supply current will be described below.

BACKGROUND Many electrical and electronic devices are powered by battery, usually to make them portable and also cheaper than mains powered equivalents. Most of these devices allow the user to select an on/off function for the device to activate it electrically and this function is generally provided for in a simple mechanically actuated electrical switch or electronic switch operated directly by the user whenever desired. There are, however, occasions when a battery powered electrical or electronic device would be preferred to be automatically switched off, or on, even when the user activated switch (the manual switch) is still on. Also, it is useful to leave a device manually switched on but with the automatic switch in off-mode with an integrated timer to activate the automatic switch to its on-mode and so to activate the battery powered device. An example of a mains equivalent to this can be seen in the many types of mains timer switches that plug into standard wall sockets and into which a mains device (turned on) is plugged and which is then activated by the on-off timed control of the timer switch.

In the case of a battery powered timer switching device there are many reasons why a load device should be automatically switched off during one or more time periods during the day or intervals related temporally to the last switching on of the controlled battery powered device. One reason is to preserve battery life when a battery powered device (BPD) is only needed during certain intervals of a day but is otherwise left on wasting battery life.

Another example is of a BPD that is used at random times but only for a maximum time period at any one time after switching on so a battery activation regulator could initially allow the battery to operate when an external load is put on the battery it controls but automatically disable the battery after a predetermined interval of operation so powering down the external device. On powerdown of the external device manually (ie manually switched off at the external device's manual switch) the battery control device would then reset itself so that on next switch-on of the external load device the battery control device allows current to be supplied for another maximum set period of time.

In this way a device that is accidentally left on would only waste a limited amount of battery power before the battery is disabled.

One very useful example of a timer battery is a timer battery that allows an enabling of the battery during a programmable interval of the day given that the external load device is switched on at its own manual switch. In this way a transistor radio, say, could be given a radio alarm function. A separate programmer would be provided to program the timer battery.

Another example of a BPD that provides a useful function is that of a selective time period activation of the battery. For instance, if a child's battery powered toy has-a timer battery that enabled the battery during only certain times of the day then the child may only use the toy during those time periods.

In particular the battery may be disabled after a certain time in the evening after which the child is expected to go to bed so preventing the child from "staying up late" playing with the toy.

In the same vain, the battery may be enabled for a set time interval after initial external electrical loading of the battery, ie switching the external device on. After the set time interval of activation the battery would be disabled for a set time interval after which the battery will be enabled again for a set time period of electrical loading (ie when the external load is present in the switched on state).

Another example is of a battery which is remote controlled in its activation (eg radio controlled, ultrasonically controlled, or some other wireless mechanism). A master control could then be used to activate/deactivate one or more batteries and thus devices, simultaneously, or selectively if provision is made for this (eg a signal with a destination battery code(s)).

Many batteries can be found on the market today with ranges of voltage, stored energy, and current ratings. The packaging geometry also varies but is of a limited set of standard shapes and sizes. A device intended to selectively enable/disable a battery needs to cope with the variation in these parameters either by providing a single flexible device or a range of devices designed to deal with a range of requirements. An internal device (ie fitted inside the battery) may be engineered into particular batteries at time of manufacture. An external device will need to cope with many package geometries. The electrical current characteristics of many batteries used domestically require only low currents (typically less than one ampere ) so that solid state technology may be used to switch such currents easily. A selective battery activating/disabling device (SBADD) could use this technology to provide a switching mechanism that has low parasitic power on the battery it controls. Integrated semiconductor devices (integrated circuits) also may consume low power, particularly CMOS devices clocked at low frequency, and may implement much functionality into a small volume for very low cost especially if very conservative integration scale is used. An SBADD could then be made very cheaply and with high functionality in a very small package on either a single integrated circuit, or a very small number of components including integrated circuits.

DESCRIPTION This invention relates to a device for selective enabling or disabling of a battery or battery arrangement either internally or externally to the battery by electrically interposing an automatic switch between one (or both) electrode(s) of the battery and the contacts which supply current to an external load. Figures 1, 2, and 3 show the internal implementation of this as an overview schematic without detailed description of the parts. Figures 4, 5, and 6 show the external implementation of this again as a general overview of the device with respect to the battery electrodes and external load contacts.

Figure 1 This shows an SBADD implemented as an integral part of a battery (B), ie internal to the normal packaging of the battery shown diagrammatically as the dotted boundary marked (B) in the figure. The SBADD device (D) is electrically in series with the battery cell (BC) on the side of the battery cells's positive electrode so that the SBADD may control the impedance of the electrical connection between the battery cell' positive electrode and the external positive contact (BPC) of the battery (B). BNC is the negative external battery contact which is connected without modification to the negative electrode of the battery cell (BC). BNC and BPC are the contacts that supply power to the external load device. NP shows an internal electrical connection from the battery cell's negative electrode to the SBADD. This line provides electrical connection possibly for powering the SBADD in conjunction with the connection from the SBADD to the positive electrode of the battery cell. It also possibly provides connection for communications with external programming devices via the battery contacts.

Figure 2 This shows an SBADD implemented as an integral part of a battery (B), ie internal to the normal packaging of the battery shown diagrammatically as the dotted boundary marked (B) in the figure. The SBADD device (D) is electrically in series with the battery cell (BC) on the side of the battery cells's negative electrode so that the SBADD may control the impedance of the electrical connection between the battery cell' negative electrode and the external negative contact (BNC) of the battery (B). BPC is the positive external battery contact which is connected without modification to the positive electrode of the battery cell (BC). BNC and BPC are the contacts that supply power to the external load device. PP shows an electrical connection between the battery cell's positive electrode and the SBADD to supply either power or also for providing additional connection to the battery's external positive contact to allow communication with an external programmer device and the SBADD via the battery's external contacts.

Figure 3 This shows an SBADD implemented as an integral part of a battery (B), ie internal to the normal packaging of the battery shown diagrammatically as the dotted boundary marked (B) in the figure. The battery cell (BC) is connected electrically to the SBADD device (D) which controls both of the battery cell's contacts with the external load contacts. The SBADD device may also take power from the battery cell connections. The positive and negative external battery contacts (BPC and BNC) are connected directly to the SBADD device (D) so that both electrodes of the battery are controlled through the SBADD to the battery external contacts. The SBADD controls all electrical connection between the internal battery cell (BC) and the external battery contacts.

Figure 4 This shows an SBADD (D) implemented as a separate device external to the battery (B) that it controls (ie external to the battery packaging). The SBADD is connected to the external positive and negative battery contacts (BPC and BNC) via conductors connected to contact arrangements at the battery's external contacts. In this figure the SBADD controls the positive battery contact by placing a contact arrangement electrically in series with and between the positive battery contact (BPC) and the positive load contact (LPC). The contact arrangement (BSCP, I, LSCP) is arranged so that the contact BSCP (battery side contact positive) is in contact with the positive battery contact (BPC) and where BSCP is electrically insulated from the load positive contact (LPC) by a layer of insulating material (I) between BSCP and another contact (LSCP) which makes contact with LPC by touching when the battery with SBADD apparatus is inserted into the load device's battery bay. LSCP is electrically connected to the SBADD device (D) to allow a controlled circuit from the battery cell's positive electrode through BPC through BSCP through D through LSCP through LPC to the load device (LD) and back to the battery cell's (BC) negative electrode through the load's negative contact (LNC) through to the SBADDS negative contact (LSCN), by making a touching contact, and then through to the battery cell's negative electrode via the battery's negative contact (BNC). Contact LSCN may be connected as in the figure to the SBADD to provide power if necessary. The dotted arrows between the contact pairs LNC and tSCN, BNC and LSCN, LPC and LSCP, BPC and BSCP indicate that a touching contact is made to provide electrical connection. Note that the circuit LNC to BNC may be made other than through LSCN if necessary.

Figure 5 This shows an SBADD (D) implemented as a separate device external to the battery (B) that it controls (ie external to the battery packaging). The SBADD is connected to the external positive and negative battery contacts (BPC and BNC) via conductors connected to contact arrangements at the battery's external contacts. In this figure the SBADD controls the negative battery contact by placing a contact arrangement electrically in series with and between the negative battery contact (BNC) and the negative load contact (LNC). The contact arrangement (BSCN, I, LSCN) is arranged so that the contact BSCN (battery side contact negative) is in contact with the negative battery contact (BNC) and where BSCN is electrically insulated from the load negative contact (LNC) by a layer of insulating material (I) between BSCN and another contact (LSCN) which makes contact with LNC by touching when the battery with SBADD apparatus is inserted into the load device's battery bay. LSCN is electrically connected to the SBADD device (D) to allow a controlled circuit from the battery cell's negative electrode through BNC through BSCN through D through LSCN through LNC to the load device (LD) and back to the battery cell's (BC) positive electrode through the load's positive contact (LPC) through to the SBADDS positive contact (LSCP), by making a touching contact, and then through to the battery cell's positive electrode via the battery's positive contact (BPC). Contact LSCP may be connected as in the figure to the SBADD to provide power if necessary. The dotted arrows between the contact pairs LNC and LSCN, BNC and LSCN, LPC and LSCP, BPC and BSCP indicate that a touching contact is made to provide electrical connection. Note that the circuit LPC to BPC may be made other than through LSCP if necessary.

Figure 6 This shows an SBADD (D) connected with a battery (B) and a load device (LD) so that the SBADD controls the electrical connection both between the battery negative contact (BNC) and the load negative contact (LNC) and between the battery positive contact (BPC) and the load positive contact (LPC). Contact arrangements between the contact pairs (LNC, BNC) and (LPC, BPC) serve to place electronics in the SBADD into series electrical connection with these two contact pairs to allow the SBADD to control the conductivity of the electrical path between these contact pairs. The contact arrangement (LSCN, I, BSCN) shows the contact LSCN to be electrically insulated from the contact BSCN. LSCN is connected to the SBADD.

BSCN is also connected to the SBADD so that the SBADD may controllably vary the conductivity between LSCN and BSCN so controlling the conductivity between BNC and LNC. The dotted arrows indicate a touch to make contact for the contact pairs ( LNC, LSCN) and (BNC, BSCN). The battery cell (BC) is shown inside the battery proper (B). At the positive side of the battery a similar arrangement of contacts and control circuitry is provided to allow control of the electrical connection between the battery's positive contact (BPC) and the loads positive contact (LPC).

BSCP is the SBADD's positive contact to the battery which makes a touching contact (dotted arrow) to BPC.

LSCP is the SBADD's contact to the load's positive contact (LCP) making a touching contact (dotted arrow).

Figure 7 shows a block diagram of the SBADD device in conjunction with a battery cell (BC) connected to an external load (not shown) via the load's negative contact (LNC) and its positive contact (LPC). The diagram follows the contact control method of figures 1 and 4 (ie disables a single contact to the positive load contact LPC). The diagram shows the device in a general form for this method of connection. Other examples of the device may use reduced functionality or different functionality to achieve the same resulting operation. The block diagram is intended only to show a functional split of the device in terms of separate functional components for the purposes of clarity in explaining the device's function. It is not intended to show a block diagram of the only possible actual device, however the figure does show a representative block diagram of a device which may be implemented in many ways to achieve the same functionality of the general device being described for the present invention.

Incorporated in this invention or its variations are means for flexibly controlling the activation of a battery via a variable impedance switch marked CVI (in the simplest case a binary off-on switch giving effective infinite or zero impedance) connected in series with the battery cell (BC) to control current flow from either or both of the electrodes of the battery, means for measuring time and duration of time provided for in a timer unit (TU) in the figure, means for storing time parameters either programmably or fixed, means for sensing or inferring current flow through the battery to some degree of accuracy provided for by a current sensor (CS) in the figure, and means for inputting information to the device from external apparatus provided for by a communications unit (COM) in the figure, and means for programming and storing internal parameters of the device from this information. In the figure the box marked CU is intended to represent a control unit that centrally controls and monitors the electronics of the SBADD. It monitors current measurements through the battery at CS, provides control signals to the switch (CVI), programs and monitors the timer unit (TU), monitors and controls the communications unit (COM), and performs all algorithms for dealing with the control of the switch (CVI). Not all functionality is necessarily implemented in all variations of the invention. Other functionality may be included as described elsewhere in this description of the present invention.

Major variations of the invention are briefly described in the paragraphs below.

Firstly a device for enabling the battery during one or more time intervals and disabling it otherwise using one or more stored time landmarks and a method for internally keeping time (eg a digital counter). Means may be incorporated for resetting or presetting the time via an external programmer connected to the load contacts of the device or to special contact(s) provided for programming.

Means may also be provided for programming the time landmarks for controlling the operation of the device.

These time landmarks may be preprogrammed into the device (eg a range of devices may be available with different standard time landmarks). Additional to the present invention a separate programmer could be used to program any programmable parameters of the SBADD (eg time landmarks). Many variations of the programming method could be employed and are documented in public literature, for instance using an electrical carrier frequency which is modulated to perform serial digital communications which is demodulated and decoded within the electronics of the SBADD.

Secondly a device for enabling the battery for a given time interval after switching on the external load apparatus.

The battery is disabled after this time interval. Means are provided for inferring the state of the external load apparatus (ie on or off) eg by sensing the current through the battery so that at a predefined or programmable threshold (ie calibration) the load is inferred to be "on".

Means are provided in the control of the battery to re enable the battery after an off-to-on transition of the external load apparatus. Means are provided in the device to implement an algorithm for determining this transition ( eg by performing tests on the load at regular time intervals say by providing some voltage to the load and sensing current flow through the battery to infer load impedance, ie on or off, at a given threshold of impedance which may be calibratable within the device). Again parameters for controlling the on-off operation of the battery may be either preset in the device or means may be provided for programming these parameters. Means for measuring time duration are also supplied (eg digital or analogue timer).

Thirdly a device for enabling the battery for a set time period after which the battery is disabled for a second set time interval. Means may also be supplied for testing the state of the load device after the disable period so that an off-to-on transition of the load apparatus must be detected before fully enabling the battery to the load contacts. Means are also supplied for measuring time duration. Means may also be supplied for programming in the time intervals for enable and disable operation. Means are supplied for storing the time intervals and for selectively enabling and disabling the battery and for controlling this operation.

Another variant on the battery controlling device relates to a remote controlled version of the device. Means are supplied for the usual battery switching function but in this device the control is via a signal received from a remote source (eg via radio, ultrasonic, ...). Means are provided for receiving and decoding such signals and for operating the switch based upon the information content of the signals.

Referring to figures 1, 2, 3, 4, 5, and 6, these diagrams show block diagrams of the electrical position of the SBADD device being described with respect to the battery electrodes and the contacts that provide current to an external load (by which is meant an external device that draws current and power from the battery). In these diagrams the SBADD is shown with power connections to the battery to draw parasitic power from the battery to maintain its own electrical functionality, though this power may be supplied by other means (eg a separate battery, capacitor, or any other source of electrical power). It is convenient however to use the battery itself as the source of power for the device particularly as it is envisaged that the device will use negligible power during the working life of the battery if the battery is used to regularly supply energy, say, to a battery powered toy, considering that such toys will usually require the driving of lights, motors, and other relatively high power electrical/electronic devices which require high currents and powers compared, say, to a low power integrated CMOS circuit or a power switching FET (field effect transistor). In all figures 1, 2, 3 and 4, 5, 6 the device implements a current controlling capability with a control system which will be described below and whose general block diagram is shown in figure 7.

One method of control for the switch which could be provided in the present invention is based upon the incorporation of a timer (eg a clock) within the device and incorporating a control unit with means for storing times for placing the switch into its on or off state. At these preselected stored times, using the timer as a mechanism for time keeping, the controller activates the switch to enable the battery to supply current and power to an external load. The controller may, in general, implement any programmable function, or subset thereof, for controlling the switch given a set of time or duration parameters prestored in the device and given that a method of time reference is provided (eg from the timer). Further the controller may also implement control functions based upon a method for sensing current flowing through the battery either directly or inferred (eg from voltage drop). This mechanism is primarily intended to allow the device to sense whether an external load is being placed (in the electrical sense) on the battery. For instance the controller could provide an electrical path between the battery and external load by reducing the impedance of the internal controlled battery current switch so as to test the impedance of the external load.

If this impedance is effectively infinite it may be concluded that the external device is in its "off" is state or that the battery is not connected. If current is drawn then the controller will sense this and will be able to decide whether the external load is significant or not, and modify its internal state according to the control function being implemented.

The switch (CVI) shown in figure 7 is, in its most general sense, a variably controlled impedance (eg the junction field effect transistor marked as JFET1 in figure 8). Many technologies may be used including relays, transistor switches/amplifiers, or any other impedance control method of one electric circuit by another (ie one electric signal by another). One simple implementation using solid state electronics is to use a junction field effect transistor (JFET) in a switching mode, ie high impedance "off" or low impedance "on" with the gate voltage to channel voltage appropriately controlled to provide the desired switching characteristic for the JFET employed. Inherent in this scheme for switching is a small loss of voltage across the channel of the JFET, around 0.2 volts if fully "on". For an SBADD implemented internally to a battery this does not provide a significant problem as the battery voltage may be designed to give the required load voltage for any given switching means. For an external SBADD then the SBADD will cause a voltage drop on the load contacts equal to the voltage drop across the JFET switch since the voltage generated by the battery is predetermined by the manufacturer. If this voltage drop is not significant for the load device then such a switch may be used. If the voltage drop is intolerable then a low voltage drop switch may be employed, eg a relay such as a bistable relay with no parasitic power (ie relay moves between two stable positions driven by a pulsed control signal, say). It is conceivable that voltage increasing methods could be employed to offset a loss over a switch though this in general increase the complexity of the device and wastes power.

Referring to figure 8, the load device (LD) is connected via positive and negative contacts (LPC and LNC) to a battery cell (BC) whose positive electrode is controlled by the SBADD device (D) that effects current control of the battery through means of a junction field effect transistor (JFET1). The SBADD (D) provides a control voltage to the gate of JFET1 so providing a means of controlling current flow through the channel of JFET1.

If a current sensor were installed to measure or infer current through the battery and to provide this information to the SBADD (D) then the SBADD could perform a range of control functions on the current flow through the battery.

Referring again to figure 7, the controller (CU) may also receive information from a notional (or actual) communication unit (COM) which in its most general sense interfaces to any external mechanism for inputting data to the device and presents this information to the controller. The primary data inputs to the controller through the communication unit are time data (for resetting the timer to a calibration time for instance), mode data for setting the mode of the controller, and timer data for setting times for enabling and disabling the battery (eg time landmarks or on/off intervals depending on the mode of control).

The communication unit could incorporate means for converting external signals to signals that may be decoded by electronics within the SBADD, eg digital decoding via a finite state machine using a serial communications protocol. External signals may arrive via electrical means, or via radio, or any other medium.

The communication unit will incorporate means for presenting the received and decoded information to the controller, and possibly for alerting the controller on reception of such information at the communication unit.

Many mechanisms exist for communicating information between a programming device and the device it programs or controls. One simple mechanism that could be incorporated into the present invention would use a modulated electrical carrier signal of a suitable frequency to provide a medium for serial digital communications. The battery contacts could be used to transmit this signal to an internal version of an SBADD, or for an external version the signal could be input to any pairs of contacts on the SBADD. Electronics in the SBADD would provide means for demodulating the carrier to reconstitute the signal which would then be decoded via some means such as a finite state machine protocol decoder.

A further aspect that may be provided for in the present invention is a means for activating the SBADD before first usage so as to extend shelf life by minimising (or completely eradicating) power taken by the SBADD before purchase and first use, in particular power taken parasitically from the battery being controlled. Many methods may be devised to enable complete functionality before first using the device; for instance the power to the device may be disable electronically in such a way that a fused "watchdog" subsystem provides a constant disable signal to the electronic disable electronics (which may be very simple and of negligible power) and this fused system may be disabled, for instance, by a high voltage pulse that blows a fuse in this electronics so as to change its state to enabling the SBADD electronics. Many standard mechanisms exist for this function and may be seen in publicly available literature. It is not necessary to enumerate such designs here other than to highlight that a mechanism for enabling the SBADD befo eradicate its power consumption).

Considering now the physical geometry and packaging of commercial batteries, the internal and external methods of battery control have different constraints that affect the physical geometry of the device and its packaging. The internal device is preferred to lie wholly within the ordinary physical boundary of a standard shape battery of which many shapes are defined and in common use.

As the device is integrated into the manufacture of the battery the problem becomes simply a problem of miniaturisation and design for the packaging process and as such is of little interest to the present invention except insofar as a suitable miniaturisation technology should be chosen (eg using integrated circuit technology where the device is implemented as much as possible on a single IC). The external device provides a more complex packaging problem since there is a strong constraint that neither the battery nor the external load device should be modified in any way physically to accommodate the external version of the present invention. Thus the physical geometry of the device must accommodate the ordinary variation of a given standard battery shape and the bay into which the battery is placed in a load device.

It is of interest to describe some possible design features of the physical layout of the external version of the present invention though, clearly, any physical layout that minimises or dispenses with the need to modify battery shape or the shape of the load device's battery bay is to be preferred to a device layout that requires such design modifications, though of course such a physical layout would still be entirely within the scope of the present invention.

Consider now two major aspects of a battery's shape that influence the physical layout of the external variation of the present invention. Firstly consider the shape and position of the battery contacts, considering also the external load contacts and their position in relation to the battery contacts in the "normal" connected state. Consider now typel (T1) and typ2 (T2) battery styles shown in figure 9 where BPC and BNC are the positive and negative battery contacts and BC the voltaic cell within the battery packaging. To account for the normal variation of battery and battery bay geometry for a given standard battery a certain degree of flexibility is usually built into the contact mechanism between load device and battery, frequently by means of sprung contacts either on the load device in type 1 batteries, or in the battery's contacts in type 2 batteries. The amount of "play" in this contact arrangement is usually of the order of one or more millimetres. It is possible then to interpose a thin contact strip between battery and load device contacts to provide a separation of these contacts electrically and to provide a conducting path to a switch (the SBADD). Figure 10 shows this diagrammatically for a type 1 battery in which the SBADD follows the design of figure 4, ie the positive battery contact (BPC) is controlled externally to the battery The labels on the diagram follow the labelling convention of figure 4 except for SLNC which replaces LSCN, and SLCP which replaces LSCP. SLNC is the sprung negative contact of the load, and LSCN is the sprung positive contact of the load. Also note that the SBADD power connection and contact is not shown. The SBADD (D) shows only a notional switch for enabling or disabling the battery though the SBADD depicted here may embody any of the functions described in this document. The important concept here is that it is possible to insulate the battery contacts from the load device contacts while providing new contacts for the load device and battery that lead to the SBADD and that this insulation and the new contacts may be thin enough and strong enough to be interposed between the battery contacts and the external load contacts. Clearly type 1 and type 2 batteries may be accommodated this way using the configurations shown in figure 4, 5, and 6. For situations where multiple batteries are connected in series, usually of type 1, then only one of the batteries need be fitted with an SBADD, the play in the contact dimensions being provided at the head and/or tail battery contacts in the chain. Parallel arrangements of batteries can not be provided for by using only one SBADD of the presently described type. In this instance a separate SBADD device would be wired in series with the parallel battery arrangement. This will possibly entail electrical insertion of an SBADD device in series with the load device between the load device and its battery contacts in the battery bay. Such an operation is best performed at manufacture of the load device as it necessitates modification of the load device circuitry.

Figure 11 shows a type 1 battery (T1) around which an SBADD apparatus is placed to provide battery and load contacts according to the method of figure 4. The SBADD packaging (DH standing for Device Housing) houses the SBADD electronics and maintains the correct positioning of the contact arrangements, CP and CN respectively, at the positive and negative battery contacts (BPC and BNC) in relationship to the position of the load device's positive and negative sprung contacts (SLPC and SLNC). The housing DH is intended to provide means for maintaining this positioning of these contacts and for providing means for packaging the SBADD electronics and wiring. The housing DH is also expected to be designed to accommodate the space limitations between a battery and the bay into which it fits. The housing may also provide means to clip itself onto the battery or bay.

Figure 12 shows a type 2 battery (T2) connected to a battery and load device in the arrangement of figure 4 where the positive electrode is controlled. LNC and LPC are the load's negative and positive contacts (sprung or not). LPC makes contact with the contact arrangement on the battery's positive contact (BPC). The SBADD is not shown in this diagram. The contact arrangement on the positive contact shows a cross-section through a possible contact arrangement that fits onto the battery contact like a sleave to provide a battery to SBADD contact and an SBADD to load contact. CHO is part of the contact arrangement housing that allows the sleave to hold onto the positive battery contact (BPC). The contact arrangement should be made thin enough to allow it to be accommodated in the standard gap, given its range of variations, between the battery contact BPC and load device contact LPC when the battery-SBADD apparatus is placed in the load device battery bay.

For the case of type 3 batteries (T3 in figure 9), ie batteries which do not have sprung loaded contact with the load device but rather have clip on contacts, several possible connection mechanisms could be adopted in the present invention. It is conceivable that a contact mechanism as described above could be used but the insulation/contact arrangement would have to be very thin so as not to prevent the clip-on action of the battery to load contacts. This is of course possible. Alternatively it is possible to fit an adapter to the battery contacts which provides a set of mating contacts for the load device. The SBADD could then be contained within the adapter and the adapter would separate battery and load contacts electrically while providing contacts for the battery and load device to the SBADD. However, the adapter would necessarily enforce a physical distance between the battery contacts and load device contacts of a size equal to or greater than the depth that the battery and load contacts would normally push into each other. This separation may be prohibitively large for some battery bay geometries though it would be acceptable for others.

Figure 13 shows a type 3 (T3) battery to which an adapter of the type described above is fitted and which in turn makes contact to a load device (LD). Shown in the figure is a housing (DH) for the SBADD and its contacts to house the SBADD electronics and to maintain the desired positioning of all the SBADD's external contacts, an SBADD device (D), positive and negative contacts (BSCP and BSCN) from the SBADD to the battery, positive and negative contacts (LSCP and LSCN) from the SBADD to the load device, the load device's positive and negative contacts (LPC and LNC), and a battery cell (BC) in the battery (T3) being controlled by the SBADD connected as in figure 6.

Consider now the second major characteristic of the geometry of a battery and the load device bay into which it is fitted. This characteristic pertains to the shape of the bulk of the battery and the physical dimensions of the SBADD device. Given that the SBADD may be connected to the battery and load device given the above methods, or any other method, then the SBADD itself must occupy some space between the battery and the walls of the bay into which the battery fits. For ergonomic reasons it is preferable for the SBADD and its electrical contacts to be housed in a single unit of relatively robust structure given normal use, though the unit may be flexible at one or more points or be entirely flexible to allow it to wrap around the battery to some extent. Usually a certain amount of room is available around a battery within a battery bay, especially if the battery bay is cuboidal in shape providing large spaces towards the corners of the bay given cylindrical style batteries such as most type 1 batteries. The SBADD housing may be designed either to fit into these corner spaces along the length of the battery or the SBADD housing could be designed to hug the contours of the battery it controls and to be thin enough to fit between the battery walls and the bay walls. The electronics of the SBADD could easily be designed to fit into a quite thin housing which supports the electrical connections to the SBADD device, especially if integrated circuit technology were used where the IC substrate is mounted directly onto the housing material or, say, a surface mount technology were used for the IC where the depth of the surface mounted IC in its packaging is shallow enough to fit inside most normal battery to bay wall gaps when mounted onto some housing. In general, the SBADD housing can be designed to any shape and any degree of flexibilty to allow the SBADD electronics to be tucked away in a free space in the battery bay while the housing also supports the electrical conductors necessary to connect the SBADD to the battery and load contacts.

Note that any electrical conductors used between the SBADD and its contacts must be rated to carry acceptable currents for use of the battery in a reasonable manner. Note also that means may be provided in the SBADD housing to clip the SBADD to the battery it controls or to clip it to the load device into which the battery to be controlled is placed. Too many variations of providing means for this exist to describe here. Design of such means will be driven by materials used, the strength required for the clip-on action, and other physical constraints. It is sufficient in the present invention to state that such means are quite standard in design given physical constraints and that such means are to be provided if necessary in the present invention to fix the SBADD to the battery or the load device.

Claims (19)

1A device incorporating means for variably changing the impedance between two of its electrical contacts which, when placed in series electrical connection with one or more batteries to which it is connected and which power an external load device, allows the current through and/or voltage across the load device powered by the battery to be modified by the action of the battery control device. The device may be either internal or external to the battery's (or batteries') packaging and be electrically connected either internally or externally to the battery (batteries) at one or both of its contacts for a single battery or at one or both of the effective power contacts of a compound battery, and the device is adapted so that the bulk physical size of the device allows the device combined with the battery (or batteries) controlled by the device to be inserted in the normal fashion of the battery (batteries) alone into the battery bay of a load device to which the battery (batteries) is intended to supply power, and is provided with means of making electrical contact with the external electric/electronic load (if the device is external to the battery packaging) so that the variable impedance of the device controls the effective internal impedance of the combined battery and device so that the current and voltage supplied to the load may be controlled by the device. If the device is external to the battery (or batteries) then the bulk of the device and its contacts are adapted to fit snugly around the battery so that the increase in physical dimensions of the battery packaging and the position of the effective battery contacts presented to the load when the device is fitted to the battery, are not altered so much as to prevent normal fitting of the combined battery (batteries) and device. If the device is internal to the battery packaging then the device is adapted to fit into the packaging of the battery and/or the battery adapted to allow the device to be fitted so that the physical dimensions of the battery and its contacts to the load device are not physically altered in their position significantly so that the combined battery and device may fit into the battery bay of the load device. Means are supplied for performing the control algorithm in the device, for instance using electronic technology such as a microprocessor based micro-computer with analog to-digital and digital-to-analog conversion means and means to adapt voltage and current levels as appropriate to supply control signals to the variable impedance mechanism (provided in the device) which controls the current and voltage supplied to the load device. The control algorithm uses time (or durations of time) or time (or durations of time) combined with the electrical activity of the load device and/or battery, as input information so that the variable impedance may be controlled as a variable function of time and/or duration of time and/or electrical activity in the load and/or battery. Any generic control algorithm based on these inputs to control the variable impedance mechanism may be provided. Means are provided in the device for measuring time and/or durations of time and/or for measuring, or inferring, the electrical activity of the battery and/or load device. The device may be self powered by an integral battery or may be adapted to draw power from the battery it controls or from any other source of power.

2 A device as in (1) for which any of the specific physical and/or electrical configurations of figures 1, 2, 3, 4, 5, or 6 are followed.

3 A device such as in (1) or (2) for which further means are provided for measuring duration of time between events such as changes in the electrical environment of the device such as switching-on or switching-off of the load device (ie change in its impedance).

4 A device such as in (1) or (2) or (3) for which further means are provided for controlling its variable impedance as a function of time and/or of elapsed time based on one or more events in its electrical environment and/or fixed temporal events such as one or more fixed, variable, or programmable time landmarks so that the internal impedance of the combined battery and device is controlled in a manner so that the current and voltage supplied to the load device may be controlled as a function of time and/or electrical activity of the load device through time.

5 A device as in (1) or (2) or (3) or (4) for which the variable impedance switch is implemented with electrical relay technology (ie high impedance or low impedance only in a binary switching manner) or semiconductor technology such as transistors (field effect, bipolar junction, optoelectric, or any other), or any other current or voltage regulating technology adapted using appropriate driving electronics to provide the desired binary, or continuous analog, transfer function.

6 A device as in (1) or (2) or (3) or (4) or (5) for which additional means is provided for communicating control information to the battery control device from an external communicating device, or for externally receiving status information from the battery control device by electrical means through the external electrical power contacts of the combined battery and device or, if desired, through the contacts of the device directly if the device is external to the battery packaging so that is may be attachably removed.

7 A device as (6) where the communications mechanism uses any serial communications protocol in which the data is embedded in a binary encoded data stream which contains synchronisation and/or packet boundary information.

8 A device as in (6) or (7) in which the communications signal between the device and an external communicating device is frequency, amplitude, or phase modulated adapted to distinguish it from the power voltage supplied by the battery so that an external programmer/status reader may distinguish the battery power signal from the communications signal and so that the communications may be conducted at an appropriate rate and manner for convenience using a serial communications technology.

9 A device as in (6) or (7) or (8) connected functionally as in the block diagram of figure 7 in which is provided a central controller (eg a microprocessor or electronic finite state machine interfaced appropriately to the sensors and actuators/amplifiers in the device) connected to a communications interface for communicating information gathered by its sensors to an external device or receive information or control signals from that device in the way described by (6) or (7) or (8) , The device functionally described in figure 7 also provides means of sensing current flow in the battery by means of, for instance, a series current sensor such as a Hall effect sensor or any other current or voltage sensing method interfaced to the controller for the purpose of sensing electrical activity in the battery or load. The device described in figure 7 also provides means for controlling a variable impedance connected electrically in series with the battery so that varying the impedance allows a variation in the effective impedance of the battery as seen by an external load so controlling the current flow and voltage at the load contacts. The device described in figure 7 also provides means for measuring time and/or duration which may be programmed and/or read by the controller. Means are provided in the controller for effecting algorithms for controlling the variable impedance as a function of any or all of the signals monitored by the controller.

10 A device as in (1) or (2) or (3) or (4) or (5) or (6) or (7) or (8) or (9) in which the controller implements an algorithm for sensing the impedance, and so indirectly the usage, of the load device by applying a voltage to the load device through means of changing the battery control device's impedance by reducing the impedance and sensing the change and/or magnitude of current flow through the device, and thus through the load, from which the impedance of the load (ie its state of electrical activity) can be inferred using the laws that govern the relationship of current, voltage, and impedance, in electric circuits. This testing of the load device impedance is performed as a function of time, eg at a regular interval, or at predefined times, or at variable times or intervals of time.

Additional means may optionally be provided for calibrating one or more threshold impedance values to label the impedance state of the load and for which means are provided for storing this information accessibly in the device for use by the control algorithm.

11 A device as in (10) for which the algorithm for testing the impedance, and thus activity, of the load is adapted to reduce the parasitic power drain by the device on the battery which supplies power to the device since any testing carried out by the device will incur power drain.

12 A device as in (1) or (2) or (3) or (4) or (5) or (6) or (7) or (8) or (9) or (10) or (11) for which the controller implements an algorithm that uses one or more fixed or programmable (via the communications mechanism) time landmarks stored in the device for controlling the operation of the variable impedance of the device and thus for controlling the power to the load device.

13 A device as in (12) for which the control algorithm switches the variable impedance into either low or high impedance state to either fully power the load or completely cut power from the load as a function of one or more of the time landmarks. In particular, the impedance is set to its low state when reaching one time landmark, and when the next time landmark is reached switches the impedance into its high state, until the next time landmark is reached at which time the impedance is set into its low state again, and so on for as many time landmarks are present.

14 A device such as in (13) where the device operates periodically over a given period, for instance in a 24 hour daily cycle, so that the high-low state of the device impedance repeats during each period.

15 A device as in (1) or (2) or (3) or (4) or (5) or (6) or (7) or (8) or (9) or (10) or (11) for which the control algorithm controls the impedance of the device as a function of activity of the load and as a function of duration of time after events in the load's electrical activity.

16 A device as in (15) in which the control algorithm places the variable impedance into its low impedance state and then tests the load impedance until the load impedance moves into its on (ie low impedance) state at which point the control algorithm waits a fixed or programmable duration of time after which point it places the device impedance into its high impedance state either for a given time period (fixed or programmable) or until the load device returns to its high impedance (ie off) state. The control algorithm then either places the devices variable impedance into its low state or waits until the load moves into its low impedance (on) state before returning the device impedance to its low impedance state again to begin the cycle again.

17 A device as in (1) or (2) or (3) or (4) or (5) or (6) or (7) or (8) or (9) or (10) or (11) for which the control algorithm places the devices variable impedance into its low state before or when the load is found to be in its low state and maintains the device's variable impedance in its low state for a given time period (fixed or programmable via the communication interface) at which point the device impedance is placed into its high state for a given time period (fixed or programmable) after which the device impedance is again placed in its low impedance state repeating the cycle.

18 A device as in (1) or (2) or (3) or (4) or (5) or (6) or (7) or (8) or (9) or (10) or (11) incorporating one or more of the control algorithm features described in (12), (13), (14), (15), (16), and (17).

19 A device as in any of the devices described in (1)..(18) where the device is internal to the packaging of a battery and incorporating additional means for activating the battery control device from a power-down or disconnected state into its fully powered-up functional state to reduce or remove any parasitic power drain on the source of power for the device before its first use so as to extend the shelf life of the battery to which it is connected.