DESC:TECHNICAL FIELD OF THE INVENTION

[0001] The present subject matter described herein, in general, relates to the field of communications, and more particularly, to a system and a method for back-up power supply/arrangements for telecom applications.

BACKGROUND OF THE INVENTION

[0002] In modern wireless telecom applications, reliable and cost-effective power supply is needed. In some regions, mains power supply is poor and power interruption frequently occurs, resulting in working suspension of the base station. Therefore, a backup power system and method is needed.

[0003] Many tower operators are using batteries in a continuous charge-discharge-cycling (CDC) operating mode, which helps to reduce the fuel costs and emissions, and improve overall system efficiency. Lead acid battery continues to be the workhorse as far as the telecom market is concerned. However poor charge acceptance of lead acid battery has long been recognized as the cause of unsatisfactory performance in areas with long duration of grid power outage. In such a scenario, the lead acid battery fails to function as an adequate backup power source. Lithium ion battery, with superior charge acceptance, can be a possible solution in such cases. Complete Li-ion battery solution can become cost-prohibitive. Thus, mobile and tower operators are increasingly looking at hybrid solutions to increase battery service life with significant cost benefits, particularly in terms of life-time cost, for storage systems in telecom application.

[0004] In the prior art, US8698448 patent provides a hybrid solution. It discloses a power supply device comprising: a lead acid battery and a lithium ion battery. The method discloses: receiving and distributing the currents supplied by the power generation apparatus to a load and a lithium ion battery to ensure normal running of the load and enable the lithium ion battery to be charged, and after the lithium ion battery is fully charged, distributing the currents supplied by the power generation apparatus to the lead acid battery so that the lead acid battery is charged. Lithium ion-lead acid hybrid battery system has been developed to cater to telecom towers as back-up power solution in areas where the cumulative daily power outage is between 8 to 16 hours. However, in case of prolonged and frequent power cuts, the lead acid battery bank is exhausted and will not get sufficient time to be able to charge properly. Further, in case of a delay or malfunction (even of a few milli sec) of the switching unit, the system causes complete shutdown of load.

[0005] Thus, in view the drawbacks of the existing battery systems for telecom applications, there exists a dire need to provide a system and method which is safe, durable, reliable and provides high performance energy storage solutions that are optimized for the higher back-up time and also prevent complete shutdown.

OBJECTS OF THE INVENTION

[0006] The main object of the present invention is to overcome the drawbacks of prior art.

[0007] It is another object of the present invention is to provide a system and method for back-up power arrangements for telecom applications.

[0008] It is yet another object of the present invention is to provide a backup power solution while improving battery service life and reduce the overall life time costs of backup power system.

[0009] It is another object of the present invention is to provide a system and method for back-up power arrangements that will prevent complete shutdown of load.

[0010] It is still another object of the present invention is to provide a system and method for back-up power arrangements in which the batteries of the hybrid system are simultaneously charged.

[0011] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

SUMMARY OF THE INVENTION

[0012] The following presents a simplified summary of the invention in order to provide a basic understanding of some aspects of the invention. This summary is not an extensive overview of the present invention. It is not intended to identify the key/critical elements of the invention or to delineate the scope of the invention. Its sole purpose is to present some concept of the invention in a simplified form as a prelude to a more detailed description of the invention presented later.

[0013] Accordingly, in one aspect, the present invention provides a hybrid battery system comprising:
at least one lithium ion type battery system (Li-ion) having plurality of lithium ion cells;
at least one lead acid type battery system (LA) directly coupled to at least one load to provide initial supply to said load, and during discharge of said lead acid type battery system said load supplied by said lithium ion type battery system;
plurality of battery management systems (BMS) connected to said plurality of lithium ion cells; and
at least one central control system (CCS) connected to said lead acid battery system and said BMS, wherein said CCS configured to supply power to said BMS and to enable data transfer to/from said BMS, wherein said CCS configured to enable balancing of power supply to said load by means of at least one boost converter and at least one buck converter.

[0014] In another aspect of the present invention, there is provided a method of operating the hybrid back up power system during power outage by using the hybrid battery system as mentioned above, wherein said method comprising;
• discharging, by a central control system, power supply from a lead acid type battery system to at least one load;
• shifting, by said central control system, from said lead acid type battery system to a lithium ion type battery system, power supply to said load;
• sending, by means of a BMS, data corresponding to said lithium ion type battery status to said central control system and facilitates complete utilization of said lithium ion type battery system;
wherein, after exhaustion of said lithium ion type battery system, shifting, by means of said central control system, said load to said lead acid type battery.

[0015] Briefly, various aspects of the subject matter described herein are directed towards a wound healing system and devices thereof and more particularly to wound healing system and devices configured to enhance wider range of bio mechanism favourable for wound healing.

[0016] Other aspects, advantages, and salient features of the invention will become apparent to those skilled in the art from the following detailed description, which, taken in conjunction with the annexed drawings, discloses exemplary embodiments of the invention.

BRIEF DESCRIPTION OF THE ACCOMPANYING DRAWINGS

[0017] The above and other aspects, features, and advantages of certain exemplary embodiments of the present invention will be more apparent from the following description taken in conjunction with the accompanying drawings in which:

[0018] Figure 1 illustrates in a block diagram the power system, in accordance with the subject matter of the present invention.

[0019] Figure 2 illustrates the electrical and logical connection of the power system, in accordance with the subject matter of the present invention.

[0020] Figure 3 illustrates a discharge profile of the Li-ion battery bank in terms of the available amp hour capacity (Ah) of individual cells of the power system during grid power outage in accordance with the present invention.

[0021] Figure 4 illustrates one charging profile of the Li-ion battery bank during the grid power ON in accordance with the present invention.

[0022] Figure 5 shows the Ah profile of each individual cell for three complete discharge-charge cycles in accordance with the present invention

[0023] Figure 6a and 6b show the charging profile of one cell in accordance with the present invention.

[0024] Persons skilled in the art will appreciate that elements in the figures are illustrated for simplicity and clarity and may have not been drawn to scale. For example, the dimensions of some of the elements in the figure may be exaggerated relative to other elements to help to improve understanding of various exemplary embodiments of the present disclosure. Throughout the drawings, it should be noted that like reference numbers are used to depict the same or similar elements, features, and structures.

DETAILED DESCRIPTION OF THE PRESENT INVENTION

[0025] The following description with reference to the accompanying drawings is provided to assist in a comprehensive understanding of exemplary embodiments of the invention. It includes various specific details to assist in that understanding but these are to be regarded as merely exemplary.

[0026] Accordingly, those of ordinary skill in the art will recognize that various changes and modifications of the embodiments described herein can be made without departing from the scope of the invention. In addition, descriptions of well-known functions and constructions are omitted for clarity and conciseness.

[0027] The terms and words used in the following description and claims are not limited to the bibliographical meanings, but, are merely used by the inventor to enable a clear and consistent understanding of the invention. Accordingly, it should be apparent to those skilled in the art that the following description of exemplary embodiments of the present invention are provided for illustration purpose only and not for the purpose of limiting the invention as defined by the appended claims and their equivalents.

[0028] It is to be understood that the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise.

[0029] By the term “substantially” it is meant that the recited characteristic, parameter, or value need not be achieved exactly, but that deviations or variations, including for example, tolerances, measurement error, measurement accuracy limitations and other factors known to those of skill in the art, may occur in amounts that do not preclude the effect the characteristic was intended to provide.

[0030] Features that are described and/or illustrated with respect to one embodiment may be used in the same way or in a similar way in one or more other embodiments and/or in combination with or instead of the features of the other embodiments.

[0031] It should be emphasized that the term “comprises/comprising” when used in this specification is taken to specify the presence of stated features, integers, steps or components but does not preclude the presence or addition of one or more other features, integers, steps, components or groups thereof.

[0032] In one implementation, the present invention relates to the hybrid battery system used during grid power outage, wherein the load will be initially catered to by the lithium-ion battery. Once the lithium-ion battery is discharged, the load will be supplied by the lead acid battery. When grid power returns, both lithium-ion and lead acid batteries will be charged simultaneously.

[0033] In one implementation, as shown in figure 1, a system for power back up comprising: a lithium-ion battery (hereafter referred to as Li-ion or LI battery bank); a lead acid battery (hereafter referred to as LA battery bank); chargers for each battery system which includes SMPS charger and BTS charger; Battery management system (BMS); and a central control system (CCS).

[0034] In one implementation, the charger for each battery system preferably includes two switched-mode power supply (SMPS) for charging of said Li-ion battery system and a BTS charger for charging of said LA battery system.

[0035] In one implementation, the present invention provides a power back –up system (Figure 1) comprising of one lithium-ion battery comprising preferably of 18 cells, one lead acid battery comprising preferably of 24 cells, two chargers for each battery system, 18 BMS (one for each lithium-ion cell) and one central control system (CCS). The LA battery bank is coupled to the load, a charger and CCS; LI battery bank is coupled to the CCS, which in turn is coupled to the LI battery bank charger; and each Li-ion cell is coupled to at least one BMS.

[0036] In one implementation, the each BMS comprises of at least three connections (figure 1):

1) One power line which is connected with the CCS and supply the power required for the BMSs to work;
2) One data line connected with all BMSs and the CCS for data transfer through this line; and
3) Inter BMS electrical line that interconnects the BMS with CCS lines, while carrying up to 7A current. This balancing is done through this line.

[0037] In one implementation, the BMS senses the voltage, temperature and Ah count of individual Li-ion cell and transfer the data to the CCS. Upon receiving command from CCS, the BMS charge (or discharge) the cell via the electrical connection between BMS and CCS. The BMS has no logical operation coded and its only function is to transfer the data to the CCS and operate according to CCS command. The BMS is fitted on individual Li-ion cells.

[0038] In one implementation, the CCS controls (Figure 2) the operation of the entire power back –up system and its function may be broadly categorized into three parts:
a. Boosting of input voltage of power source to a suitable voltage for charging the LI battery bank. The Boost converter is the interface between the Li-ion charger and CCS. In an exemplary implementation, the Li-ion charger voltage may be set at 54V; the boost converter raises this voltage to 67V required for charging the Li-ion battery.
b. Bucking down the LI battery bank output voltage to a suitable voltage to disconnect the LA battery bank from the load and by doing so supply the load from the LI bank. The buck converter is the interface between load and the system; the converter steps down the LI battery bank voltage from a higher voltage to lower load voltage (for example 53V) also that this voltage is higher than the fully charged LA battery bank voltage. It suppresses the discharge from LA battery bank and prioritizes the discharge of LI battery bank. Only after the LI battery bank is exhausted, the buck voltage is released and LA battery bank starts to supply to the load.
c. Analyzing and processing of the system status and control the system. The Central Control has the main processing IC fitted here which receives the data from BMSs and based on these data, generates commands. The control unit sends signals to the following units for
(i) The Buck, Boost converter, to control the charge / discharge current.
(ii) The BMSs to charge, discharge (and hence balance) the cells. By processing the data, the control unit starts the lithium-ion to lead acid battery share / switch of the load. It also selects the weaker cells and calculates the balancing current and action required for the same.

Characteristic features of EIL Li-ion- LA Hybrid System:

[0039] In one implementation, referring to figure 3, during the grid power outage:
? Once the power is off, the load immediately starts discharging the lead acid bank.
? After maximum 30 sec (response time), the lithium-ion bank takes over when the CCS senses no voltage across the charger (i.e., no grid power available)
? The Lithium-ion bank discharges and supply the load till either cell Ah is exhausted or any cell reaches to lower voltage limit.
? The electronic control system balances the lithium cells so every cell discharges their available Ah capacity

[0040] This graph in figure 3 shows one discharge profile of the Li-ion battery bank in terms of the available Ah of individual cells. It can be observed that though all cells have different initial Ah, after 30 min to 1 hr of discharge, the remaining available Ah of every cell became almost same. More importantly, all cells are completely discharged at the same time. This ensures maximum utilization of the available Ah of all cells in the battery bank.

[0041] In one implementation, reference made to figure 4, during grid power is set ON:
? The Lithium ion battery starts charging as soon as the load is OFF and the charger is ON. Simultaneously the lead acid battery bank is charged through a separate charger;
? The electronic system charges the battery till every cell reaches to their full capacity;
? The system feeds extra current to individual cells so that all cells reaches to their respective Ah capacity at the same time.

[0042] This graph in figure 4 shows one charging profile of the Li-ion battery bank. It can be observed that despite all cells start to be charged at same available Ah (zero), at the end of charge every cell have reached to their respective Ah capacity.

[0043] In one implementation, figure 5 shows the Ah profile of each individual cell for three complete discharge –charge cycles.

[0044] In one implementation, figures 6a and 6b show the charging profile of one cell; it can be observed that the cell received almost 100% of its input Ah through the bulk charge mode. Only a small quantity of Ah input is required in the balancing stage. This allows to drastically reduce the overall balancing time for the Li-ion battery bank.

[0045] In one implementation, the method of operation of back-up power system comprises of initialization of the system where the Ah capacity of individual cells may be fed to the CCS to run the system on self-calibration mode.

[0046] In one implementation, the system at rest has the LA battery bank charger keep the LA battery bank at the set float voltage. The LI battery bank charger will remain off and the Lithium cells will remain in open circuit condition.

[0047] In one implementation, the method of operation of back-up power system during discharge and charging comprises of the following steps:
a) during grid power outage discharging starts from LA battery bank;
b) after initial response time of the CCS (30s), load shifts to the LI battery bank;
c) BMSs sends the battery status to the CCS, which ensuring complete utilization of Ah of individual lithium-ion cells, all through maintaining balance among the cells in the battery bank;
d) After LI battery bank Ah is exhausted, the load shifts to the LA battery bank;
e) on resume of power or charging LI battery bank charger starts charging the Li-ion cells and LA battery bank charger starts charging the lead acid cells;
f) BMSs send the battery status to the CCS, which controls the system ensuring complete charge input as per the respective Ah capacity of individual cells, all through maintaining balance among the cells in the battery bank;
g) after each cell receives 100% of their discharged Ah, the charging stops.

[0048] In one implementation, the back-up power system is self-calibrated. After a pre-determined period / cycles of charge and discharge, the system will recalibrate itself. During recalibration the system discharges all Li-ion cells to a preset lower voltage cut off. These cells are then charged to a preset voltage cut off and then discharged to the same lower voltage cut off to obtain the Ah capacity of individual cells. These discharged Ah values will be taken as the recalibrated capacity of the cells.

[0049] In one implementation, the CCS will monitor individual cell voltage both during charge and discharge; the CCS will monitor individual cell voltage and if any of the individual cells voltage rises/decreases beyond a certain preset higher/lower voltage limit, the charging/discharging will stop. While once the discharge is stopped, the load will be shifted to LA battery bank; once the charging is stopped, the cells will be charged to their 100% discharged Ah via a small charging (balancing) current through the individual BMSs.

[0050] Some of the important features of the present invention, considered to be noteworthy are mentioned below:
1) The present invention provides separate power supply (chargers) for both batteries and this makes this model more useful in high power cut areas.
2) The present invention provides a power back up system which is protected from mishaps and the load will always remain on. The lead acid battery is at the front end directly connected to the load. In the unlikely event of malfunction of the electronics / Li-ion battery bank, the load will still be catered to by the lead acid battery.
3) The hybrid battery configuration allows the lead acid battery to be on float charge.
4) In the present invention the cells are being actively balanced and therefore chances for overcharging cases are slim.

[0051] Some of the non-limiting advantages of the present invention are mentioned below:
1) The present invention provides a back-up system which improves battery service life and reduces the overall life time cost of back-up power system;
2) The present invention provides a back-up power arrangement that prevents complete shutdown of load;
3) The hybrid battery configuration is safe, durable, reliable and provides high performance energy storage solutions that are optimized for higher back up time;
4) The hybrid back –up system of the present invention is useful for prolonged and frequent power cuts;
5) In back up power arrangement of the present invention, the batteries of the hybrid system are simultaneously charged

[0052] Although a system with hybrid battery back-up and related methods of operation have been described in language specific to structural features and/or methods, it is to be understood that the embodiments disclosed in the above section are not necessarily limited to the specific features or methods or devices described herein. Rather, the specific features are disclosed as examples of implementations of the hybrid battery system.
,CLAIMS:1. A hybrid battery system comprising:
a. at least one lithium ion type battery system (Li-ion) having plurality of lithium ion cells;
b. at least one lead acid type battery system (LA) directly coupled to at least one load to provide initial supply to said load, and during discharge of said lead acid type battery system said load supplied by said lithium ion type battery system;
c. plurality of battery management systems (BMS) connected to said plurality of lithium ion cells; and
d. at least one central control system (CCS) connected to said lead acid battery system and said BMS, wherein said CCS configured to supply power to said BMS and to enable data transfer to/from said BMS, wherein said CCS configured to enable balancing of power supply to said load by means of at least one boost converter and at least one buck converter.

2. The hybrid battery system as claimed in claim 1, comprising: at least two charger for each of said lithium ion battery system and lead acid battery system.

3. The hybrid battery system as claimed in claim 1, wherein said charger preferably includes a switched-mode power supply (SMPS) charger for charging of said Li-ion battery system and a BTS charger for charging of said LA battery system.

4. The hybrid battery system as claimed in claim 1, wherein said BMS adapted to sense voltage and/or temperature and/or battery capacity of said lithium ion cells, and transfer data corresponding to said lithium ion cells to said CCS.

5. The hybrid battery system as claimed in claim 4, wherein said BMS comprising:
at least one power connection line electrically connected to said CCS for receiving supply from said CCS;
at least one data connection line to connect said BMS and said CCS to facilitate said data transfer;
an inter BMS connection line that interconnects said BMS with the CCS lines.

6. The hybrid battery system as claimed in claim 2, wherein said boost converter is interface between said charger for said lithium ion battery system and said CCS.

7. The hybrid battery system as claimed in claims 6, wherein said boost converter adapted to step up input voltage of said lithium ion type battery system from a low voltage to a high voltage for enabling charging of said lithium ion battery system.

8. The hybrid battery system as claimed in claims 1, wherein said buck converter is interface between said load and said CCS.

9. The hybrid battery system as claimed in claims 1-8, wherein said buck converter adapted to step down output voltage of said lithium ion battery system from said high voltage to a low load voltage for enabling discharge of said lead acid type battery system, and to enable supply to said load by using said lithium ion battery system.

10. A method of operating the hybrid back up power system during power outage by using the hybrid battery system as claimed in claims 1-9, wherein said method comprising;
discharging, by a central control system, power supply from a lead acid type battery system to at least one load;
shifting, by said central control system, from said lead acid type battery system to a lithium ion type battery system, power supply to said load;
sending, by means of a BMS, data corresponding to said lithium ion type battery status to said central control system and facilitates complete utilization of said lithium ion type battery system;
wherein, after exhaustion of said lithium ion type battery system, shifting, by means of said central control system, said load to said lead acid type battery.