DE102008003811A1 - Battery operated danger detector with power buffer device - Google Patents

Abstract

A battery-operated hazard detector (100) is described. The hazard detector (100) has a battery terminal (112a, 112b) arranged to connect a battery (110), a current controller (120) connected in parallel with the battery terminal (112a, 112b), and a hazard detection module (130), which is connected without the interposition of a clocked voltage converter to the battery terminal (112a, 112b). The current buffer device (120) is set up in such a way that current from the current buffer device (120) for the danger detection module (130) can be provided during periods with a high current drain through the danger detection module (130) and at times with a low current drain by the danger detection module (130). Power from the battery (110) to the current buffer means (120) is transferable. In this way, the time course both of the current (Ibat) to be provided by the battery (110) and the voltage (Uin) provided for the danger detection module (130) can be considerably smoothed. On the one hand, this improves the stability of the voltage (Uin) and, on the other hand, extends the service life of the battery (110), in particular if the battery is a lithium battery (110) and in particular a lithium thionyl chloride battery ( 110).

Description

The The present invention relates to the technical field of hazard detection technology. In particular, the present invention relates to a battery powered one Danger detector, which provides an electronic circuit for providing a time constant as possible Supply voltage for has a battery-operated hazard detection module of the hazard detector. The present invention further relates to an operating method for the battery-powered danger detector.

Next There are also danger detectors fed by a danger zone those that are powered by a battery. This is especially true for danger detectors, which are equipped with a radio module and thus without consideration on existing supply and / or data lines anywhere a supervised Room can be attached.

For the business a danger detector can different types of batteries are used. In addition to the usual Alkali-manganese batteries or alkaline batteries with a voltage of about 1.5 volts increasingly also used lithium batteries, which is a particularly have a long life.

When Smoke detectors trained hazard detectors are often based on optical scattered light measurements. In this case, a light beam emitted by a light source is through Smoke particles scattered and at least partially towards a light detector directed. To the average power requirement of a scattered light smoke detector It is known to pulsate the light source. This means that the light source cyclically only for comparatively short periods are activated and the remaining time is switched off is. The same applies Radio modules of a battery-operated hazard or smoke detector, which also for the purpose of saving power between two successive ones Transmitting phases is turned off.

One such pulsed operation for cyclic monitoring and / or for cyclical transmission of detection results, for example, to a control center of a entire danger reporting system has the consequence that cyclic and pulse-like comparatively much power needed becomes. The current drain pulses are then interrupted by longer current resting phases. However, this behavior has an adverse effect on battery life out.

Especially professional radio hazard alarms with long service life Mostly used with a clocked voltage converter. In this case, the variable battery voltage is in a constant supply voltage reshaped. At the time of the load pulse, the voltage at the battery terminals Massively reduced by the internal resistance of the battery. This must be be compensated by the voltage converter again. Works with it the voltage converter is not in the optimal working range and reaches so that not the full conversion efficiency and requires additional power. This has considerable in part Losses result, which also the life of the connected Adversely affect the battery.

Of the present invention is based on the object, the power supply a battery-powered hazard detector for a longer life to improve the battery.

These Task is solved through the objects the independent one Claims. Advantageous embodiments The present invention is described in the dependent claims.

According to one The first aspect of the invention is a battery-powered hazard alarm described. The hazard detector indicates (a) a battery connection, set up for connection a battery, (b) a current buffer device which is parallel to is connected to the battery terminal, and (c) a hazard detection module, which without the interposition of a clocked voltage converter connected to the battery connector. According to the invention Stream buffer device configured such that (i) in time periods with a high current drain through the danger detection module current of the stream buffer device for the danger reporting module can be provided and (ii) in time segments with a low current drain through the danger signaling module power from the battery to the power buffer device is transferable.

Of the The present invention is based on the finding that a connected to the battery current buffer device for a short Time duration low-impedance can supply power and thereby the voltage maintained in periods with a high current drain can be. In the typically longer breaks in which the Danger detector no or at least only a very low power consumption has, the power buffer device of the battery can power again which slowly charges it.

The comparatively high current drain through the danger detection module can take place at regular or even irregular intervals. Decisive for a fault-free operation of the danger detector is merely that sufficient time remains between two consecutive current draws to the current buffer device without a recharge the battery to a greater extent. With regard to the absolute time length of the current draw, there is neither a fundamental upper limit nor a principal lower limit. Thus, the current draws, for example, current pulses with a current of 30 mA and a pulse length of 50 ms be that repeat regularly in a fixed interval of, for example, 2 s.

It is pointed out that of course still so-called. Linear or non-clocked voltage transformers used for the purpose of voltage smoothing can be. these can also between the battery connection or a connected battery and the input of the hazard detection module.

Of the Hazard alarm, for example, a fire or smoke detector, a Intrusion or intrusion detector and / or gas detector be, which when exceeded a predetermined minimum concentration of a particular gas one Alarm message outputs and / or this alarm message to a central Device forwards.

Of the described danger detector can be used with any type of disposable and / or rechargeable batteries. As disposable batteries come, for example, so-called alkali-manganese batteries in question, as Rechargeable batteries come, for example, nickel-metal hydride batteries or lithium-ion batteries in question.

According to one embodiment the invention, the battery connector is adapted to connect a Lithium battery and in particular a lithium thionyl chloride battery.

lithium Batteries have opposite Alkaline manganese batteries or alkaline batteries have the advantage that with the same capacity and geometry a much longer Battery Life can be achieved. Furthermore lithium batteries have a clear same geometry and capacity longer Lifespan than conventional Alkaline batteries. This is especially because the cells are voltages from lithium batteries compared to alkaline batteries significantly higher are.

lithium Batteries also have the advantage that they last throughout their life provide a largely constant voltage. This can be beneficial to Way on additional electronic components for voltage adjustment or voltage regulation waived and still a reliable operation of the danger detection module guaranteed become.

According to one another embodiment of the Invention, the battery terminal is adapted for connection (a) a lithium-thionyl chloride battery, (b) a lithium-iron-sulfur battery, (c) a lithium-carbon-fluorine battery, (d) a lithium-manganese-oxygen Battery, and / or (e) a lithium-sulfur-oxygen battery.

Especially Lithium thionyl chloride (LTC) batteries currently appear to be special suitable to while a long life a largely constant voltage ready to be able to make. batteries based on the LTC technology have a cell voltage of approximately 3.3 V. More specifically, over the lifetime of the LTC battery, the cell voltage always between about 2.8V and 3.6 V. This allows conventional Danger alarm modules with an operating voltage of about 3 volts be operated without the use of lossy voltage transformers. This applies to both so-called up-converter as well as for Down converter, which increased or compared to a primary voltage provide reduced voltage. Because such voltage transformers typically work with high-frequency switching pulses, can through the avoidance of such clocked voltage transformers the load by electromagnetic radiation, which, for example, a radio communication can disturb be significantly reduced. By dispensing with a voltage transformer can be compared to known battery-powered hazard detectors Furthermore reduces the power loss and the material costs for the production the danger detector can be significantly reduced.

As a result of the described current buffer device, a relatively uniform current is drawn from the connected lithium battery in comparison to a conventional danger detector without a current buffer device. In a pulsed operation, a pure rest period without any current drain from the connected battery is thus at least largely avoided due to the intended charging phases between two consecutive current draws. This is particularly advantageous when using LTC batteries, in which a fast passivation takes place during a resting phase without any current drain, which should prevent or at least reduce a self-discharge of the battery. However, such a passivation, which would occur repeatedly with a pulsed current drain, would have a very detrimental effect on the life of a lithium battery. This is due to the fact that in a pulse mode a passivation starts in each current pause and this would have to be at least partially reduced again during a relatively short current pulse. Naturally, losses occur. By using the described stream buffer device, these disadvantages can ever but avoided in a simple and effective way and a longer life of a lithium battery and in particular a LTC battery can be guaranteed.

It It is noted that of the mentioned battery types Lithium based only the lithium iron-sulfur battery with a voltage of about 1.5 volts significantly from about 3 volts voltage different lithium battery types. When using usual Fire detection modules with a required supply voltage of 3 volts would be Consequently, two series-connected lithium-iron-sulfur batteries required to provide the required voltage. Of course, however, could Also a fire detection module can be used, which is a lesser Supply voltage of only about 1.5 volts required.

According to one another embodiment of the Invention, the current buffer means comprises a capacitor. The use of a capacitor for energy storage or for smoothing the voltage applied to the danger detection module effective supply voltage has the advantage that the power buffer device with a simple and reasonably priced electronic component can be realized. The capacity of the capacitor can be advantageously dimensioned such that a usually by a certain interval predetermined input voltage for the hazard detection module at the beginning of a load pulse not exceeded and at the end of a Pulse load is not exceeded. Especially with comparatively strong short-term current loads, the capacitor during a comparatively long rest period by the connected battery be recharged.

It It should be noted that the capacitor is usually a parasitic or inherent Ohmic resistance having. To effectively smooth the effectively on the danger detection module to achieve applied voltage, the parasitic resistance should be the current buffer device be significantly smaller than the internal resistance the connected battery.

According to one another embodiment of the Invention, the danger detector additionally has a Entkoppelwiderstand which is arranged between the battery terminal and the current buffer device is.

The Use of a decoupling resistor between the battery connection and the power buffer means has the advantage that the battery of the power buffer device is at least partially decoupled. Such decoupling or decoupling is particularly advantageous, if the danger detection module has a pulse load for the connected battery and / or for represents the stream buffer device. A good decoupling between connected battery and the current buffer device is also also then advantageous if the connected battery comparatively huge Internal resistance.

According to one another embodiment of the Invention, the battery-powered hazard alarm additionally Radio module, which is also connected to the battery connector is. By the described radio module, the battery-powered Danger detector within a wireless radio communication network be directly or indirectly connected to a central office. The radio module can do this and the hazard detection module in an advantageous manner of the same Supply voltage to be fed, so that the power buffer device automatically for one smoothing all required supply voltages ensures.

The Radio module can be a conventional radio module be, which is operated with an operating voltage of 3 volts. This lithium batteries are particularly suitable for effective Supply of the described danger detector.

It It should be noted that the radio module is also used together with the Hazard detection module can be implemented in a common module.

According to one Another aspect of the invention is a method for operating the specified above battery-powered alarm. The specified method comprises (a) providing power from the stream buffer device for the danger detection module in periods with a high current drain through the hazard reporting module and (b) transferring power from the battery to the current buffer device in time intervals with a low current drain through the danger detection module.

the described operating method is based on the finding that through the use of a current buffer device, which is parallel is connected to the battery terminal, removed from the battery amperage with regard to temporal changes smoothed can be. In particular, in a pulse load operation, the Load cycles for the battery of the battery-operated danger detector are damped. This has a positive effect on the lifetime of the Battery connection connected battery.

The smoothing of the time course of the current, which is provided by the battery, also has the advantage that the danger detection module can always be supplied with a suitable supply voltage without the need for active elements such as a designed as up or down regulator voltage regulator. As a result, the production of the danger detector can be simplified and material costs can be saved. Since voltage regulators typically operate with a high-frequency clocking, the electromagnetic compatibility with regard to an electromagnetic contamination caused by the danger detector in the described danger detector is considerably reduced in comparison to known danger detectors.

Further Advantages and features of the present invention will become apparent the following exemplary description of presently preferred embodiments.

1 shows a battery-powered optical smoke detector, which has a designed as a capacitor current buffer device.

2a shows the time course of the current, which of the in 1 required danger detection module is required.

2 B shows the time course of the current to be provided by the battery for the danger detection module for a danger detector without current buffer device and a danger detector with current buffer device.

2c shows the time course of the voltage applied to the danger detection module voltage for a hazard detector without a current buffer device and a danger detector with stream buffer device.

1 shows an optical smoke detector 100 which is from a battery 110 is powered. The battery 110 is shown by means of an equivalent circuit diagram. Accordingly, the battery points 110 a voltage source providing the battery voltage Ui 111 and an internal resistance Ri. The battery 110 is by means of a battery connection 112a . 112b to the smoke detector 100 connected. The connection contact is used 112a Contacting the positive pole of the battery 110 , The connection contact 112b serves to make contact with a ground line of the smoke detector 100 with the negative pole of the battery 110 , The ground line is connected to a ground GND.

The smoke detector 100 further comprises a stream buffer means 120 which is connected in parallel with the battery terminal. According to the embodiment shown here, the current buffer device 120 a capacitor C with a parasitic resistance Rc. This shows the current buffer device 120 in the case of a change over time of the current to be supplied by the battery, a typical RC behavior. That is, depending on the sign of the change of the current, charge is supplied from the capacitor C or charge is taken up by the capacitor C. As a result, the power buffer device carries 120 to a smoothing of the battery 110 to be provided stream at. As a result of the non-disappearing internal resistance Ri of the battery 110 This will also make it automatic from the battery 110 at the connection contacts 112a and 112b smoothed out voltage provided. According to the embodiment shown here, the parasitic resistance Rc is significantly smaller than the internal resistance Ri.

Between the battery 110 and the power buffer device 120 is also a decoupling resistor 115 provided, which is arranged according to the embodiment shown here in the positive supply line. The through the decoupling resistor 115 caused partial decoupling between the battery 110 and the power buffer device 120 has the advantage that in particular in the case of a low internal resistance Ri in a pulse load operation, the battery charging pulses from the current buffer device 120 or be decoupled from the capacitor C at least partially.

It is expressly noted that the resistance 115 for the described power supply of the smoke detector 100 is optional. In addition, one could resist 115 corresponding resistor may alternatively be arranged in the ground line, which the connection contact 112b with the power buffer device 120 combines. Furthermore, it would be conceivable to switch in each case a decoupling resistor in both the positive supply line and in the ground line.

The danger detector 100 also has a hazard detection module 130 on which a fire detection module 132 and a radio module 134 includes, both of which are supplied by a voltage applied to the positive supply line input voltage Uin. The one of the danger detection module 130 required electricity is in 1 marked with Ilast. The one from the battery 110 Provided current is shown with Ibat.

The fire detection module 132 has in known manner all the components required for the detection of smoke. According to the embodiment illustrated here, the fire detection module is based 132 on the principle of optical scattered light measurements. As a result, the fire detection module includes 132 a light source, not shown, and a light detector, also not shown, with the illumination light emitted by the light source after an at least partial scattering can be detected in particular by smoke particles.

The radio module 134 allows the described battery operated hazard detector 100 in a known manner a wireless communication with a not shown center of a wireless radio communication network. The radio module can do this 134 be connected directly or indirectly via other hazard alarms with the control center.

According to the embodiment shown here, the radio module 134 a conventional radio module, which is operated with an operating voltage of 3 V. The radio module 134 will work together with the fire detection module 132 from the battery 110 provided. The battery 110 For example, it may be a lithium thionyl chloride (LTC) battery.

According to the embodiment shown here is the danger detection module 130 arranged such that in a regular 2 seconds interval for a duration of 50 ms each, a current I load of 30 mA is needed. This short load pulse is supplied for the most part from the capacitor C. This is true in any case if the resistor Rc connected in series with the capacitor C is substantially smaller than the internal resistance Ri of the battery 110 ,

The capacitance C is dimensioned so that the voltage Uin, which at the danger detection module 130 is present, at the beginning of a load pulse, a predetermined working range of the hazard alarm module 130 does not exceed and that the voltage Uin at the end of a load pulse does not fall below the specified working range. During the long resting time compared to the duration of the load pulse, the capacitor C is replaced by the battery 110 recharged.

2a shows the time course 250 of the electricity demand Ilast of the danger detection module 130 of in 1 shown danger detector 100 , According to the embodiment shown here, every 2 seconds a 50 ms long load pulse 252 required with a current of 30 mA. In the meantime, a quiescent current 254 of only 2 μA needed.

2 B shows the time course 260 of the battery 110 for the danger detection module 130 provided stream Ibat. With the reference number 263 is the case by the current buffer device 120 Smoothed course of the battery 110 provided electricity.

For a better illustration of the current buffering described in the US Pat 2 B Diagram also shown the hypothetical current waveform, which from the battery 110 without providing a power buffer device. This hypothetical current profile is denoted by the reference numeral 261 characterized. The one of the danger detection module 130 needed a short load pulse 262 with a current of 30 mA in this case beats directly on the battery withdrawal current.

2c shows the time course 270 the voltage applied to the danger detection module input voltage Uin. The permissible working range for the danger detection module 130 is through the two dashed lines 275 clarified. The with the reference number 273 provided curve shows the input voltage Uin, as they pass through the current buffer device 120 was smoothed. How out 2c As can be seen, the smoothed input voltage is always within the prescribed operating range 275 ,

For direct comparison is in 2c even the hypothetical voltage curve 271 shown which of the battery 110 without a power buffer device would be provided. As a result of the voltage drop across the internal resistance Ri of the battery 110 At a big battery current Ibat may be from the battery 110 only a lower voltage can be provided, which with a small time offset to the required load pulse 262 below the permissible working range 275 lies.

It It should be noted that the embodiments described herein only a limited Choice of possible variants represent the invention. So it is possible the characteristics of individual embodiments suitably combine with each other, so for the skilled person with the embodiments explicitly shown here a variety of different embodiments are to be regarded as obviously disclosed.

Claims (7)

Battery operated danger detector with • a battery connection ( 112a . 112b ), designed to connect a battery ( 110 ), • a stream buffer device ( 120 ), which are parallel to the battery connector ( 112a . 112b ), and • a danger detection module ( 130 ), which without the interposition of a clocked voltage converter with the battery connector ( 112a . 112b ), the stream buffer device ( 120 ) is set up in such a way that - in time intervals with a high current drain through the danger detection module ( 130 ) Power from the power buffer device ( 120 ) for the hazard detection module ( 130 ) can be provided and - in periods with a low current drain through the danger detection module ( 130 ) Electricity from the battery ( 110 ) to the stream buffer device ( 120 ) is transferable. Battery-operated danger detector according to claim 1, wherein the battery connection ( 112a . 112b ) is set up to connect a lithium battery ( 110 ). Battery-operated danger detector according to one of claims 1 to 2, in which the battery connection ( 112a . 112b ) is arranged to connect (a) a lithium thionyl chloride battery, (b) a lithium iron sulfur battery, (c) a lithium carbon fluorine battery, (d) a lithium manganese oxygen battery, and / or (e) a lithium-sulfur-oxygen battery. Battery-operated danger detector according to one of claims 1 to 3, in which the current buffer device ( 120 ) has a capacitor (C). Battery-operated danger detector according to one of claims 1 to 4, additionally having a decoupling resistor ( 115 ), which between the battery connection ( 112a . 112b ) and the stream buffer device ( 120 ) is arranged. Battery-operated danger detector according to one of claims 1 to 5, in addition to a radio module ( 134 ), which is also connected to the battery connector ( 112a . 112b ) connected is. Method for operating a battery-operated danger detector ( 100 ) according to one of claims 1 to 6, comprising the method • in time intervals with a high current drain through the danger detection module ( 130 ), Providing power from the stream buffer device ( 120 ) for the hazard detection module ( 130 ), and • in periods with a low current drain through the hazard detection module ( 130 ), Transferring electricity from the battery ( 110 ) to the stream buffer device ( 120 ).