The present invention relates to a battery charge equalizer for multiple type of batteries connected in series to be equally charged. More particularly, the present invention relates to the IoT based charge equalization circuitry and method of charge equalization of multiple type of batteries along with monitoring, control and management of complete system.
RELATED ART
[002] Repeated charge and discharge cycles of battery, lead to large non-uniformities in battery charge levels and corresponding differences in battery terminal voltages over a period of time because of slight differences in battery chemistry of an individual battery. During charging of a battery string composed of a series of batteries, some batteries will consequently reach full charge before others and before the overall battery terminal voltage reaches its nominal value. Such a process leads to overcharging of a subset of batteries. If these batteries are charged into the gassing phase, there can be significant degradation of the battery life. If a battery monitoring and recharging is done on a single-battery basis, it is possible to maintain each battery at its optimal operating point, and maximize battery life. Hence, it is common to provide charge equalization for all the batteries in a string.
[003] The conventional battery charge equalizers are constituted with shunt resistors, which have a series of connected battery strings; resistors; switches; battery voltage sensing and controlling circuits. The battery voltage sensing and controlling circuits monitor the charging-discharging condition of each battery of the series connected battery

strings. As any one of the batteries, for example the first battery has reached its pre-determined voltage value earlier than the others the battery voltage sensing and controlling circuits output a signal to turn on the switch letting a part of the current, which originally charges the battery pass through the resistor to maintain the battery voltage without overcharging it so as to avoid damaging the battery. Hence, the series connected battery strings can be charged to a proper voltage level without overcharging. But, this type of battery charge equalizer with shunt resistors will waste energy and are inefficient.
[004] There is another type of conventional battery charge equalizer, which is constructed with a fly back converter with a transformer consisting of one primary coil and a number of identical secondary coils equal to a number of batteries, which draws out current from the whole battery system and directs the output energy to the batteries with the lowest voltage. Under ideal conditions, this system is in a standby mode. A simple comparator monitors the battery voltages. The fly back converter is activated as soon as one of the voltages deviates by more than a pre-determined tolerance value. A switch will be switched on and off with a high frequency and the energy will be transferred from, the whole battery string via the transformer and the rectifying diodes to the individual battery. During this process, the battery with the lowest voltage will determine the voltages induced in the secondary coils. As all the coils are mounted on a common core, all the voltages induced in the secondary coils are equal, and the largest proportion of the secondary current will flow into the battery with the lowest voltage without the need for any additional selection logic, so that the charge

of series connected battery strings can be maintained to a proper voltage without overcharging.
[005] However, there are two drawbacks in this type of battery charge equalizer constructed with a fly back converter. One of them is that the battery charge equalizer constructed with a fly back converter requires a plurality of sets of secondary coils charged equally in a series connected battery strings with a plurality of batteries, which mounts all the coils on a common core to render all the voltages induced in the secondary coils equal. Thus the structure of the transformer is complicated and is difficult to manufacture. The other difficulty is that as the battery charge equalizer is constructed with a fly back converter, it is difficult to design a symmetric transformer of the fly back converter as each mounted coil on a common core has a plurality of sets in the secondary coil. So the effect of charge equalization is reduced. Furthermore, the type of battery charge equalizer constructed with a fly back converter in the various numbers of the batteries of the series connected battery strings is not conveniently adjustable. Diagnostic circuits have been proposed in some applications and are likely to be about as costly as the new equalization approach.
[006] Reference may be made to the following:
[007] IN 1899/Del/2008 talks about battery charge equalizer adapts a batter}' charger so as to equally charge serially connected battery strings, comprising a controller, logic and driving circuits, operates to prevent the serially connected battery strings from being unbalanced. The system includes a plurality of capacitors and switching elements. Each of the capacitors is switched back and forth between a

predetermined pair of batteries for the purpose of transferring unbalanced charge between them and equalizing the output voltages of each of the batteries in the pair. This is only for lead acid batteries.
[008] US patent no. 6150795 relates to the battery charge equalization is carried out utilizing modules connectable in staggered relation between pairs of batteries in a series connected string of batteries. Each module is standardized and has the same construction as the other modules. The modules may be constructed to provide unidirectional charge distribution down the string.
[009] Reference may be made to the article entitled "Bidirectional Multi-Input and Multi-Output Energy Equalization Circuit for the Li-Ion Battery String Based on the Game Theory" by Jiayu Wang, Hindawi, Volume 2019 talks about equalizer that has the modularized circuit topology and the mutually independent working principle. A static game model is developed and exploited for the mathematical description and control analysis of an energy equalization circuit comprised of these equalizers. The feasible control of each equalizer was obtained by solving a series of linear equations for the Nash Equilibrium of the model among the states of charge of the battery cells. The complexity of equations grows linearly with the cell number. The equivalent simulation model for the four-cell equalization is established in the PISM software, where the operational data and simulation results justify the static game model and verify the control validation, respectively. It is concluded that the proposed inductor equalizer is suitable for large-scale battery strings in energy storage systems, electrical vehicles, and new energy power generation applications.

[010] US patent No. 20060132089 discloses a battery charge equalizer connected to a plurality of batteries in series comprising of a control unit signaling a plurality of switches coupled to a number of capacitors, a current protection unit attached to the battery bank, a voltage/temperature sense unit and a battery desulphator circuit along with PWM driver controlled by said control unit driving isolated multiple gate output.
[Oil] Publication No.CN 100372213 talk about a device consists of charger, charging switch, equalizer, current direction detector, controller and battery back composed of two batteries connected each other in series. Each battery composing battery pack is connected to an equalizer in parallel. The equalizers are connected in series. One of two equalizers located at most outside is connected to switch of charging, and the other one is connected to current direction detector. The charge switch and current direction detector are respectively connected to the charger. The controller is separately connected to the charge switch and current direction detector.
[012] GB Patent no. 2337166 and US Patent no. .6064178 is using series RC circuit to store charge from batteries and further transfer it to lower charge battery but this patent employs R to charge and discharge the capacitor to achieve the object. Therefore, if substantial current increases then there will be power loss across R.
[013] US Patent no. 6841971 using LC for achieving charge balance, but once again power loss will occur across L when it will be directly shorted (switched) to battery.

[014] US Patent no. 2004113586 using single C to achieve charge balance between batteries. This will take much more time to balance the plurality of batteries serially connected and time will increase with increase in number of batteries.
[015] WO Patent no. 2006082425A1 is a method of battery management system having switched mode fly-back dc-dc converter as active charge balancer. The drawbacks of such charge balancer are already discussed above.
[016] US patent no. 20060012341 describes a battery management system, but it doesn't provide the facility of battery charge balancing to equalize the battery voltage of series connected batteries.
[017] US Patent no. 2008018301 and 7288919 shows a voltage balance circuit/method, voltage-detecting circuit/method. In this, voltage balance is achieved through capacitors connected serially but of disadvantage of this circuit as shown in fig. 4 of the patent mentioned is the current passes through capacitor 58 may be in both directions. So resultant current will be less that reduces the amount of charge transfer and it results in long time required for charge balance. Also it is not possible to control the amount of charge transfer as per battery string state of charge demands. So, this results in more time for achieving the charge balance depending upon battery/cell capacity and state. The charge transfer control can be achieved only by changing power transfer capacitor value in circuit as per battery charge state.
[018] US Patent no. 5710504 is using active power transfer method to transfer power between battery string connected serially. In this patent also it is not possible to buck or boost the power transfer as per battery

string state of charge demand. So this results in more time for achieving the charge balance depending upon battery/cell capacity. Buck or boost power transfer can be achieved only by changing power transfer capacitor value in circuit every time as per battery charge state/capacity. Battery state monitoring (battery management) is not done in this invention so customer alert is not possible through audio/visual messages. Further, data monitor of connected individual battery balancing unit is not possible and Auto/manual battery voltage sense and detection is not possible i.e. for 2V cell and 12V battery.
[019] US Patent no. 6624612 is a method of active charge balance circuit, which has single charge transfer capacitor between series connected plurality of batteries. In this, charge transfer between batteries will take long time to balance whole string.
[020] US Patent no. 20020190692/US6518725 provide a charge balance method using series connected capacitors along with digital switch in place of discrete power switch. So charge transfer between batteries will depend upon power carrying rating of digital switch, as it is known that digital switch have low power rating. So, it can be concluded that, this invention is suitable for low capacity batteries and it will take long time to charge balance higher capacity batteries.
Reference is to be made to a publication by Kutkut, N.H. et.al, Volume
2, Issue Page(s): 686 - 690, Feb 1998. The article discloses a new
technique for equalizing a series battery stack using a modular non-
dissipative current diverter. /

[021] Reference can also be made to a publication by Yuang-Shung Lee, IEEE, Oct 2002. The article explains a new bidirectional non-dissipative battery equalization scheme for the series battery strings.
[022] Further, reference is to be made to a publication by Philip T. Krein et.al, IEEE, INTELEC, 2002. The article reviews battery behavior and performance related to the equalization problem, in the context of valve-regulated lead-acid batteries.
[023] Reference is to be made to a publication of Battery power Online (Vol-8, issue5) by Jonathan Kimball and Brian Kuhn of Smart Spark Energy Systems, Inc., September 2004.
[024] Reference may be made to a publication by Tsukamoto, K et.al, IEEE, Feb 1993. The article proposes an algorithm for improving the speed of a charge-balancing analog-to-digital converter implemented by a switched-capacitor technique.
[025] Therefore, a practical apparatus and method should be capable of equalizing multiple type of batteries during a charge cycle, during battery discharge, or during idle times. It is very desirable to provide simple, reliable, low-cost equalization circuits can be built.
[026] With all the above discussed restrictions or limitations, it is required to have an improved battery charge equalizer. In the present invention, the IoT based equalization device for the charge transfer to needy battery unit/cell irrespective of cell type (lead acid or lithium) by using proper capacitor-switch matrix to achieve the required charge balance of series connected plurality of battery string. The amount of charge transfer is controlled through the IoT based control circuit

based on the difference in charge state of the connected batteries. If the difference is large the charge transfer can be increased by proper selection of switch matrix to reduce the time required to balance the batteries. In the present invention, any number and any type of series strings of storage batteries can be equalized with N number of Equalizer unit.
OBJECTS OF THE INVENTION-
[027] The primary object of the present invention is to provide an IoT based charge equalization circuitry.
[028] Another object of the present invention is to provide IoT based battery charge equalizer employing a numbers of the multiple type of batteries in series thus forming a battery string that is conveniently adjustable.
[029] Yet another object of the present invention is to provide IoT based battery charge equalizer using lithium or lead acid battery selection system.
[030] Still object of the present invention is to provide IoT based battery charge equalizer for electric vehicle to equalize the charge of lithium or lead acid battery.
SUMMARY OF THE INVENTION
[031] Accordingly the present invention provides Iota based battery charge equalizer for equalizing the charge of batteries irrespective of their type. The controller senses the voltage difference between batteries connected serially and accordingly switches ON/OFF the

[034] In another aspect of present invention charge transfer rate could be'increased or reduced as required according to the capacity of batteries connected. This is done through IoT from remote location.
[035] The present system and method are usable irrespective of the battery technology. Voltage will be matched between adjacent batteries regardless of chemistry, manufacturer, or capacity. The present equalizer can be used with long series strings of batteries or even individual cells without limit. For U number of equalizer, maximum (3U+1) numbers of batteries can be connected.
[036] In an aspect of the present invention, N series strings of storage batteries are used. The system extends the life, capacity of the battery and reduces battery replacement, which again reduces the cost. As the batteries are connected in series, it is easy to install. It is suitable for N number of batteries by utilizing multiple units together. The equalizer operates in all three modes i.e. battery charging, discharging or in idle mode.
[037] In one aspect of the invention, a plurality of identical equalizing modules could be provided. The modules can be coupled to a plurality of batteries to be equalized.
[038] The equalization takes place regardless of level of change. The user controls the process through IoT which is in communication with the controller of the equalized. The voltage is kept constants and current varies. IoT based battery management systems of lead acid and lithium ion batteries is based on solar charging. The voltage is fix and current varies to change the voltage an equalizes the cell and when the difference in the battery voltages reduces below a defined threshold

capacitor-switch matrix to transfer the charge between the battery with low charge and battery with high charge. The main control section monitors the battery voltages continuously and selects a proper combination of switch matrix based on the voltage difference between the connected batteries, ff batteries have large unbalance, battery, string gets balanced with more charge transfer. So battery balance time could be reduced and an effective balancing can be achieved. If there is a more charge unbalance between particular set of batteries, in that case particular set of batteries can be balanced with higher charge transfer between them. Decision for concern batteries is taken by the main controller.
[032] The main controller also monitors the battery temperature through external temperature sensor and gives indication and/or alarm in case it crosses a threshold limit. The total current with which the batteries are charging or discharging is also measured with the system.
[033] In the system capacitor switch matrix is selected in a manner to maintain charge transfer rate at maximum as capacitor has their charge discharge life cycle. With greater charge-discharge cycles the charge storing capability of capacitor degrades over a period of time. Therefore, in order to maintain charge store and transfer efficiency of capacitor multiple set of capacitors are provided one set of capacitors works for a defined time period and another set of capacitor works after that and this process takes place alternately after predefined period.

level equalization process is stopped once the difference increases above another threshold the process starts again. A single system is used to equalize Lithium Ion as well as lead acid batteries.
[039] In another embodiment of present invention, capacitor switch matrix could be increased to any number to achieve further desired buck-boost power transfer scheme for balancing the serially connected battery/cell string.
BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS
[040] Further objects and advantages of this invention will be more apparent from the ensuing description when read in conjunction with the accompanying drawings and wherein:
[041] Fig. 1 shows an overall block diagram illustrating a system and a method in accordance with the present invention;
[042] Fig. 2 shows Control section.
DETAILED DESCRIPTION OF THE INVENTION WITH REFERENCE TO THE ACCOMPANYING DRAWINGS
[043] Figure 1 illustrates block diagram of the system in accordance with the present invention.
[044] Accordingly the present invention provides IoT based battery charge equalizer for equalizing the charge of batteries irrespective of their type. The equalization takes place regardless of level of change. The user controls the process through IoT which is in communication with the controller of the equalized. The voltage is kept constants and

current varies. IoT based battery management systems of lead acid and lithium ion batteries is based on solar charging. The voltage is fix and current varies to change the voltage an equalizes the cell and when the difference in the battery voltages reduces below a defined threshold level equalization process is stopped once the difference increases above another threshold the process starts again. A single system is used to equalize Lithium Ion as well as lead acid batteries.
[045] The system includes a control unit 2 with IoT interface 2a. PV panels 2b for providing solar charging. A plurality of capacitors and switches coupled together in a matrix formation. The control unit 2, via control lines, provides signals to the plurality of switches. A current protection unit 3 is also attached to the battery bank 1, which provides high current protection to the power supply section of the system 4. A PWM driver 5 controlled by main controller 2 drives isolated multiple gate output 6, which is connected to the power transfer section 7 which consist of capacitor switch matrix. This section is also attached to the current protection unit 3 to protect unit from high current.
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[046] A voltage, temperature, current sense unit 8 monitored by controller 2, is attached to the battery bank 1 which senses the string current of battery in order to protect connected battery bank 1 from abnormal condition. In-circuit program section 9 is to program the controller 2 in circuit from PC/Programmer. A communication interface section 10 having connectors is provided to receive and transmit the data messages from one equalizer unit to another or to an external system for monitoring and control of a numbers of battery equalizer units connected to N number of batteries connected serially. The display 11 unit shows the measured parameters of the connected

system. A buzzer section 12 is provided which is fully controlled from central controller 2 and it provides alerts by giving continuous beep in case of abnormal conditions during the operation. It reports irregularities in battery temperature, irregularities in battery voltage and provides detailed information on the number of life cycle used up corrected with temperature compensation. The battery desulphator section 13 is provided to desulphate the battery plates by providing high frequency pulse currents to the batteries connected. A single unit is made to fulfill the need of an equalizer and battery desulphator 13.
[047] The controller 2 also monitors the charging discharging current of the battery string with current sensor 17 and with the help of this signal the controller can generate a signal from section 14 to inform any external system 16 such as battery charger, inverter or UPS etc to stop the charging current in case of abnormal conditions of the system such as high current, high temperature or high voltage etc.
[048] The section 15 is the address selection switch combination for the address configuration of an individual unit for communication with each other and master unit. The controller 2 reads the address configured to the device for identification of device during communication. The device with the address zero is configured as master and communicates with all the connected systems to collects the information from all the systems.
[049] Driver power supply circuit comprises of input voltage which is fed from battery bank connected with the system. The regulator herein has been used as a switch mode buck converter. A resistive voltage divider network is utilized to get desired voltage output, diodes at input

are used to protect the circuit from being damaged in reverse polarity condition. Diode at output of regulator is a freewheeling diode and capacitors at input/output are used as a filter. The output is then fed to a linear regulator which generates for example a 3.3V /5V supply and is also fed to driver to switch isolated transformer to generate multiple gate drive outputs.
[050] To generate the photovoltaic power supply PV modules are provided with solar charge controller to charge the battery. Alternately, supply of 5V a linear regulator has been utilized whose input is driver supply output. This circuit can give +5V to +3.3V (as desired). The circuit has overload and short circuit protection. The capacitors used have enough high voltage rating to safely handle the iriput voltage fed to the circuit. Further-, this supply is utilized to power-up all control section including controller 2, in-circuit programmer 9, communication interface section 10, voltage/temperature sense circuit 8, display section. 11 and buzzer drive section 12, display section.11, battery desulphator circuit 13.
[051] Generation of the PWM signal is carried out by controller and fed to driver section to drive the isolated transformer primarily at desired frequency to generate multiple isolated gate drive output so as to drive power switches (Mosfets/IGBT/Transistor). Driver is finally controlled from main controller 2 and has multiple PWM input and output. Isolation of multiple gate drive output is done through transformer having one input winding and multiple isolated windings as output to drive plurality of power switches. Zener diodes and resistors are used to limit gate drive output of each winding at desired level. The

controller also provides the PWM for driving the battery desulphator circuit.
[052] The display section is an array of LED's/LCD connected to the controller. Tri color LED Display represents different messages related to battery voltage and temperature. A provision of connecting the LCD is also provided which shows the battery voltages, temperature and current state of the system.
[053] Temperature of individual battery can be measured by using external temperature sensor/thermistor. The sense signals of individual battery temperature are fed to the controller for monitoring and display purpose.
[054] The controller sends alerts the user using IoT during abnormal conditions that may be related to unit or related to plurality of battery bank.
[055] The alternate switching and Capacitor-Switch matrix is controlled by the main controller and operated at desired frequency. By proper selection of switches, the capacitors connected can be provided in parallel to increase the power transfer by increasing the resultant capacitance. One set of switches and capacitors can be used alternately for power transfer.
[056] Current protection in system is provided through glass fuses, these fuses are assembled in input/output wire harness for easy replacement of it in field. In place of glass fuse we can also use auto fuse, resettable fuse, electronic switch and even miniature circuit breakers.

charging battery set can be appropriately charged in equalization, which not only increase the charging/discharging times of the battery set, but also efficiently extends the battery life in application. Multiple modules can be used, for example, in combination with multiple batteries which are coupled in series to one another. All the modules are connected through communication port so that the data of all the modules can be saved in each module. Thus, the status of all the modules can be viewed from any module.
[058] It is to be noted that the present invention is susceptible to modifications, adaptations and changes by those skilled in the art. Such variant embodiments employing the concepts and features of this invention are intended to be within the scope of the present invention, which is further set forth under the following claims: -

WE CLAIM;
1. An IoT based battery charge equalizer to equalize the charge of multiple type of batteries in electric vehicle comprises a control unit signaling a plurality of switches coupled to a number of capacitors, a current protection unit attached to the IoT based battery management systems of lead acid and lithium ion batteries which is based on solar charging characterized in that voltage is fix and current varies to change the voltage an equalizes the cell , isolated multiple gate drive output is connected to power transfer section, a voltage/temperature sense unit and a battery desulphator circuit along with PWM driver controlled by said control unit driving isolated multiple gate output wherein the equalizer Communicates with inverter for inverter OFF on charging.
2. The IoT based battery charge equalizer, as claimed in claim 1, wherein said lead acid and lithium battery are selected separately as both have separate battery management systems.
3. The IoT based battery charge equalizer, as claimed in claim 1, wherein the number of cell is also variable while keeping current constant.
4. The IoT based battery charge equalizer as claimed in any of the preceding claims wherein multiple set of switches and capacitors matrix are provided in which switches and capacitors matrix increases the life of the capacitors used for charge transfer.