FIELD OF INVENTION
This invention relates to a battery protection device. More particularly, the present invention provides a battery protection device which is user settable.
BACKGROUND & PRIOR ART OF THE INVENTION
The need for special battery protection circuits has increased due to the widespread use of batteries such as lithium-ion batteries, which are inherently less tolerant of adverse operating conditions than more traditional batteries such as those using nickel-based chemistries. Circuits have been used to detect whether battery voltage or current exceeds a predetermined safe level and take certain compensatory actions upon detection of such conditions. For example, if excessively high battery current is detected, a protection circuit may turn off a protection transistor arranged in series with the battery, interrupting the flow of current.
For applications in which it is important to make efficient use of stored battery power, it is desirable that protection circuitry consume as little power as possible. Additionally, many battery applications are particularly cost sensitive. For such applications, it is important that the battery protection circuitry be relatively simple, compact, and easily manufactured.
Also the conventional circuit is associated with a drawback that, there is no protection from over discharge of the battery when a malfunction occurs due to a shock by an exterior power supply or a static electricity since it is not possible to operate a switch to disconnect the main power supply in the product using battery causing a short lifetime of a battery. The other drawback is that there is no protection from over voltage when using an exterior power supply.
Further, the conventional protection device for a secondary battery does not detect the malfunction until abnormality such as excessive charging or the like occurs and hence a protecting operation is often too late. Accordingly, in the event that the temperature rise progresses rapidly, there is a possibility of the smoking and ignition.
Reference may be made to the following known arts:
US patent no 5,493,485 relates to a protection device for an inverter which is connected to an AC power system, converts DC power into AC power, supplies the AC power to a load and includes a control circuit for detecting a phase and a frequency of an output voltage, for generating a current reference synchronized with the output voltage and for controlling the inverter such that an output current is coincident with the current reference.
US patent no 7,397,221 is directed to a battery protection device which protects a battery from an abnormal state. The battery protection device includes a detector that detects an abnormality of the battery and outputs an abnormality detection signal when the abnormality is detected. A current is input to an input terminal from outside.
US patent no 6,433,514 discloses to a battery protection circuit that includes a moisture detection circuit, a temperature sensing circuit, and a high-temperature battery discharge circuit. The moisture detection circuit includes a pair of conductive traces closely spaced on a substrate such that a resistive path is formed between the traces when moisture forms on the substrate.
Publication no JP2000184734 is an inverter device which avoids the abrupt operation stop of an inverter device by giving advance warning of the consumption of a DC power supply such as a battery before the inverter device stops its operation.
US patent no 5,853,908 relates to a protective device for batteries having a high energy density such as lithium ion batteries. The protective device includes a current conduction cutoff means having a current-conducting circuit comprising a voltage-detecting means for detecting the voltage of at least one battery being charged, a heat-generating resistance for starting the conduction of a current when the detected voltage exceeds a preset voltage, and a temperature fuse thermally coupled to the heat-generating resistance.
US publication no 20090021217 relates to the method and device for safety protection of a secondary battery capable of preventing smoking and ignition thereof. A lithium cell as a chargeable and dischargeable secondary battery, a protection circuit for shutting down charging power PC at the time of over current, over voltage, etc. and an electric power restriction circuit for limiting the charging power PC input to the lithium cell are incorporated into a battery pack.
US patent no 5,637,980 relates to battery charging/discharging switching control protective circuit including a charging discharging loop, a constant current control circuit connected to the input terminal of the charging discharging loop, a microprocessor control circuit
Application no 1339/DEL/2006 relates to the lithium-ion battery protection method and device which controls an externally connected circuit to charge/discharge a rechargeable battery so as to prevent the rechargeable battery from over charging/discharging.
Various battery protection circuits are described in the patents 7,385,794, 6,503,647, 5,945,810, 5,986,865, 5,581,170, 3,656,045, 20030027036, 20060187602, 20030027036 and 20060187602. However, none of the above described systems described are user settable so that they can meet the requirement at the suitable condition.
US publication no 20090322284 relates to battery protection circuit and protection method for a rechargeable battery is provided. The rechargeable battery includes a positive voltage pin, a negative voltage pin, and a temperature sensing pin. A resistance of the temperature sensing pin varies with the temperature of the rechargeable battery. The battery protection circuit includes a temperature and voltage detection unit and a discharging unit. The temperature and voltage detection unit is coupled between the positive voltage pin and the temperature sensing pin, and configured to determine the temperature of the rechargeable battery according to the
resistance of the temperature sensing pin. This patent provides protection against a predefined temperature and battery voltage only by disconnecting load switch. User settable settings and PC based parametric setting are not available along with temperature compensation feature. Also the protection from high current is not available in this invention.
US publication no 20090128094 relates to an alarm-including protection apparatus and method to protect a lithium-ion battery with a plurality of series cells. The protection apparatus includes a voltage balance controller for detecting the terminal voltage of each cell and correcting the terminal voltage of each cell. A protection unit and the lithium-ion battery are connected in series. A microprocessor connects to the voltage balance controller and the protection unit for receiving the terminal voltage of each cell and figuring out a voltage difference between the maximum terminal voltage and the minimum terminal voltage of the series cells. According to the comparison result of the voltage difference and a plurality of critical voltage differences, the microprocessor is used to correct the terminal voltage of each cell, generate an alarm signal or stop charging to the lithium-ion battery. This patent describes the protection of particularly lithium ion battery cell/string connected in series. User settable settings and PC based parametric setting are not available along with temperature compensation feature.
Publication no 2992/KOLNP/2007 relates to a protection circuit for protecting a secondary battery from overcharging and excessive discharge current by a simple circuit. The protection circuit is provided with a connection terminal for connecting the secondary battery; a connection terminal for connecting a charging device for charging the secondary battery and/or a load device driven by a discharge current from the secondary battery; a bimetal switch that is provided between the connection terminals and turned off in the case of exceeding a specified temperature set beforehand; a heater for heating the bimetal switch and an integrated circuit for turning the bimetal switch off by causing the heater to generate heat if a voltage
applied to the connection terminal by the secondary battery exceeds a preset reference voltage. In this patent disconnecting device used is a bimetal switch, but in present invention it is a static switch. User settable settings and PC based parametric setting are not available along with temperature compensation feature. This invention doesn't have protection from high current.
US publication no 20090058365 discloses secondary battery protection semiconductor device which protects the secondary battery by detecting values of at least plural detection items corresponding to the secondary battery including the detection items of overcharge, over discharge, charge over current, discharge over current, short-circuit current, and overheat; comparing the detected values with corresponding detection levels that are determined beforehand for each of the detection items; and based on the comparison results, turning on/off a discharge control transistor and a charge control transistor that are series-connected to the secondary battery. User settable settings and PC based parametric setting are not available along with temperature compensation feature.
US publication no 20090315517 discloses a charging/discharging protective circuit for a secondary battery pack, having an over-charging/discharging voltage comparator, a reference voltage source and a battery status decision circuit. There is also a sampling circuit having a sequential pulse generator for generating pulses for selecting one of the batteries in the battery pack for testing purposes. User settable settings and PC based parametric setting are not available along with temperature compensation feature. The patent doesn't have protection from high current.
Publication no WO2009145577 relates to a balancing apparatus for a battery pack with an over-discharge protection function. The balancing apparatus according to the present invention is for balancing charge voltages in each of the battery cells in the battery pack, and includes a discharge resistance arranged on a wire connected in parallel to both ends of a battery cell. The user settable settings and PC based
parametric setting are not available along with temperature compensation feature. Apart from these protection from high current is also not available.
Publication no CN101527448 provides a testing device of a battery protection circuit. The battery protection circuit comprises a battery voltage detection unit for sending a protection trigger signal when detecting that the Vcc voltage of a power port reaches a preset protection threshold; and a control unit for generating an impedance regulation signal according to the protection trigger signal, and the impedance regulation signal is used for regulating the impedance between the power port in a drive unit and a charge protection execution end Cout or a discharge protection execution end Dout. The user settable settings and PC based parametric setting are not available along with temperature compensation feature. Apart from these protection from high current is also not available.
US publication no 2009146614 protection methods, circuits and devices are provided to protect against fault conditions within a battery pack that is operatively attached to a power tool or charger, so as to prevent internal or external damage to the battery pack or attached tool or charger. The exemplary methods, circuits and devices address fault conditions such as over-charge, over-discharge, over-current, over-temperature, etc. User settable settings and PC based parametric setting are not available along with temperature compensation feature.
Publication no CN101483335 relates to high integration density battery protection circuit with a switch protection tube that can automatically break the connection between a battery and a charger when over-charge, over-discharge, over-current. The invention comprises a master switch tube, a master switch tube grid control circuit, a master switch tube substrate control circuit, an alteration countermeasure circuit, a status initialization circuit and a section converting circuit and all are integrated on one same semi-conductor substrate. User settable settings and PC based parametric setting are not available along with temperature compensation feature.
US publication no 2009317699 relates to a battery overheating protection device used in an electronic device is provided. The electronic device includes a main unit configured to implement basic functions of the electronic device and a battery unit configured to supply power to the main unit. The battery overheating protection device includes a temperature monitoring unit, a switch unit and a processing unit. User settable settings and PC based parametric setting & over current sense protection are not available along with temperature compensation feature.
Thus, it is beneficial to provide a battery protection circuit which can improve the lifetime of the battery as well as product having the batteries.
The present invention provides a protection scheme for an efficient battery protection device which can be employed between the power system and battery. Additionally, the battery protection device is user settable.
OBJECTS OF THE INVENTION
Primary object of the present invention is to provide a battery protection device.
Another object of the present invention is to provide a battery protection device which can improve the life of the battery.
Yet another object is to provide a protection device which is user settable.
Still another object of the present invention is to enable miniaturization through building a battery protection circuit utilizing controller.
Another object of the present invention is to provide a battery protection device which avoids certain conditions that may shorten battery life and thus it results increase in the battery life.
Yet another object of the present invention is to provide a device which protects a battery from a predefined conditions of deep discharge state by alarming users and by disconnecting the power system (inverter/UPS/charger/converter) automatically when the power systems is failed to avoid such undesirable condition.
Another object of the present invention is to provide a battery protection device which protects the battery from deep discharge condition depending on the rate of discharge of the battery and ambient temperature.
Still another object of the present invention is to provide a battery protection device which is simple in construction, cost effective, user friendly and settable.
Again another object of the present invention to improve the quality of power systems such as but not limited to inverter, UPS, charger and converters using the above-described protection circuit.
Yet another object of the present invention is to provide a battery protection circuit which can be used between the inverter/ UPS/ charger/any type of converter and the battery.
Still another object of the present invention is to provide a user settable battery protection device which can meet the requirement at the suitable conditions.
Another object of the present invention is to provide a battery protection device with battery temperature compensation.
STATEMENT OF INVENTION
According to this invention, there is provided a battery protection device comprises controller, temperature sensors for compensation/protection to sense the battery temperature, which connects and disconnects the battery as per predefined limit, a power supply section to power up the controller and associated complete discrete circuitry, a voltage and current sense circuit to monitor battery voltage along with
incoming & outgoing current of battery wherein the controller connects or disconnects the battery upon comparing these signals with predefined battery settings, a static connect & disconnect unit connected to the external device, a driver to activate and deactivate the static power switches as per command received from controller, a plurality of switches, a buzzer for the audio alarm in case of abnormal condition, an enable/ disable switch to activate and deactivate the battery protection system and a display to monitor current status along with limited latest history data in connection with each other.
SUMMARY
According to this invention, a user settable battery protection device is provided which is used between the battery and inverter/ UPS/ charger/ any type of converter. The device provides the protection against abnormal conditions. A power switch is provided to disconnect the battery from the power system in the case of abnormal conditions; temperature compensation feature is added in order to maximize battery life.
In a preferred embodiment, the device has a controller which controls the switching device according to the predefined conditions. The controller with built-in programmable fuzzy logic controls the entire operation the device as per the defined set of parameters. It reconnects the battery after the abnormal condition is over. If the problem is repeated, it permanently disconnects the battery. Parameters such as but not limited to over voltage, over current, under voltage, under current, low temperature, high temperature, over charge can be adjust by the user to perform the operation as per the requirement. A single device monitors single as well as multiple batteries connected in series or parallel. Controller stores all the data such as but not limited to history, parameter details and provides the status of the battery as well as the power system. The user sets required value as per battery requirement which is needed within a specified extreme and lower limit. The device shows status through audio/ visual messages. The device also shows previous recorded events. Temperature compensation feature is provided to keep battery temperature under limit through
adopting PWM controlled static switch in charging stage and in discharging stage. If the temperature goes beyond specified limit, the device disconnect the battery/battery bank though static switch. The device reconnects the battery/battery bank after abnormal condition is over.
In another embodiment of the present invention, the switches can be dip switches, capacitive switches, inductive switches, touch sense switches, tap switches or any other kind of switches.
In yet another embodiment of the present invention, the external device can be inverter, UPS, charger or any type of converter.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWING
Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawing and wherein:
Figure 1 shows the block diagram of the battery protection device.
DETAIL DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWING:
Reference may be made to fig 1, which shows the block diagram according to the present invention. A user settable battery protection device is provided between the battery and inverter/ UPS/ charger/ any type of converter. The device provides protection against abnormal conditions. The present invention comprises controller 1 which takes every decision according to program fed into it and temperature sensors for compensation/protection 2 which senses the temperature through precision temperature sensors. The controller 1 senses the battery 3 terminal temperature and accordingly connects and disconnects the battery 3 as per predefined limit. Temperature compensation 2 becomes operational when battery 3 receives charge from charging source. The controller 1 senses the ambient temperature and
accordingly reduces max charge voltage limit of the battery 3 i.e. -3mV to -5mV/Cell/°C. This is carried out through duty cycle control of static switches. The power supply section 4 powers up the controller and associated complete discrete circuitry. Voltage and current sense circuit 5 monitors battery voltage along with incoming & outgoing current of battery and accordingly, the controller 1 connect or disconnect the battery 3 after comparing these signals with predefined battery 3 settings, in normal state switch remains closed and in abnormal state switch gets open automatically. The static connects & disconnects unit 6 comprises static power MOSFETS/ IGBTs as connect & disconnect device and is connected to the external device 6a.
Driver 7 is used to activate and deactivate the static power switches 6 as per command received from controller 1. Switches 8 for voltage cum current setting sets battery 3 charge and discharge voltage/ current level with surge current limit by user as per type and capacity of battery 3. A buzzer 9 is provided for the audio alarm in case of abnormal condition. The buzzer 9 is initialized for continuous duty as well as for discontinuous duty. The enable/ disable switch 10 is provided to activate and deactivate the battery protection system. LED/ LCD display 11 is provided to monitor current status along with limited latest history data.
System has facility for interface with PC and online data could be monitored 12 by means of GUI and battery related parametric setting could be done by user precisely under predefined limits. Performance and event data of battery get logged and monitoring can be done whenever required.
The controller 1 controls the switching device according to the predefined conditions. The controller 1 with built-in programmable fuzzy logic controls the entire operation of the device as per the defined set of parameters. It reconnects the battery after the abnormal condition is over. If the problem is repeated within a predefined limit, it permanently disconnects the battery. Parameters such as but not limited to over voltage, over current, under voltage, under current, low temperature, high temperature
and over charge can be adjusted by the user to perform the operation as per the requirement. A single device monitors single as well as multiple batteries connected in series or parallel. The controller 1 stores all the data such as but not limited to history, parameter details and provides the status of the battery as well as the power system. The system has its own memory to store a definite amount of latest battery status data and can be recalled whenever required. If device is connected to PC, a huge amount of history data could be stored automatically and online data can be monitored and user programmable setting could be done.
In the aforesaid protection circuit, a time control unit is provided which includes parameters detection unit that detects the parameters of the power source and a delay unit that controls the length of time from the detection of the abnormality of the parameters of the power source.
The present invention is equipped with sensors for detecting charging and discharging power of a secondary battery, a charging and discharging amount deriving unit for time-accumulating the charging and discharging power to determine an energy amount, and a protecting operation unit for stopping charging and discharging of the secondary battery when the energy amount has reached a given value. Thus, by measurement of AH capacity extracted from battery and AH capacity entered in battery it can easily judge state and charge level of battery and in other words it can indicate its current capacity and degradation also.
This invention is advantageous in such ways as protecting the battery from an abnormal state from a preset values by alarming users by detecting any abnormal condition. The present invention provides a flexible solution to protect product as well as battery. User can set all the parameters at which the system must be stopped as per user's choice. The present invention provides temperature compensation unit through which user can also set the temperature as per the requirement. The device has the user settable feature to set desired battery parameter as per application, type

and capacity of the battery. This is done limited through hardware dip switch setting and broadly with PC communication interface.
Numerous modifications and adaptations of the system of the present invention will be apparent to those skilled in the art, and thus it is intended by the appended claims to cover all such modifications and adaptations which fall within the true spirit and scope of this invention.

WE CLAIM
1. A battery protection device comprises controller, temperature sensors for compensation/protection to sense the battery temperature, which connects and disconnects the battery as per predefined limit, a power supply section to power up the controller and associated complete discrete circuitry, a voltage and current sense circuit to monitor battery voltage along with incoming & outgoing current of battery wherein the controller connects or disconnects the battery upon comparing these signals with predefined battery settings, a static connect & disconnect unit connected to the external device, a driver to activate and deactivate the static power switches as per command received from controller, a plurality of switches, a buzzer for the audio alarm in case of abnormal condition, an enable/ disable switch to activate and deactivate the battery protection system and a display to monitor current status along with limited latest history data in connection with each other.
2. A battery protection device as claimed in claim 1, wherein the device compares/ monitors state and charge level of battery and indicates the current capacity and degradation.
3. A battery protection device as claimed in any of the preceding claims, wherein the device is provided with user settable feature to set desired battery parameter as per application , type and capacity of the battery.
4. A battery protection device as claimed in any of the preceding claims, wherein the protection device is provided between the battery/ battery bank and inverter/ UPS/ charger/ any type of converter.
5. A battery protection device as claimed in any of the preceding claims, wherein the device monitors single as well as multiple batteries connected in series or parallel.
6. A battery protection device as claimed in any of the preceding claims, wherein the controller stores all the data such as but not limited to history, parameter details and provides the status of the battery as well as the power system.

7. A battery protection device as claimed in any of the preceding claims, wherein the user sets required value as per battery requirement and need within a specified extreme and lower limits of the various parameters.
8. A battery protection device as claimed in any of the preceding claims, wherein the device shows status through audio/ visual messages along with previous recorded events.
9. A battery protection device as claimed in any of the preceding claims, wherein the switches can be dip switches, capacitive switches, inductive switches, touch sense switches, tap switches or any other kind of switches.
10. A battery protection device substantially as herein described with reference to the accompanying drawing.