WO2020101521A1 - Method and system for monitoring a battery cell state and a battery system state without interruption of functioning of a battery system - Google Patents

Method and system for monitoring a battery cell state and a battery system state without interruption of functioning of a battery system Download PDF

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Publication number
WO2020101521A1
WO2020101521A1 PCT/RU2018/000750 RU2018000750W WO2020101521A1 WO 2020101521 A1 WO2020101521 A1 WO 2020101521A1 RU 2018000750 W RU2018000750 W RU 2018000750W WO 2020101521 A1 WO2020101521 A1 WO 2020101521A1
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Prior art keywords
battery
battery cell
state
battery system
offline
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PCT/RU2018/000750
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French (fr)
Inventor
Ivan Vladimirovich KOLCHIN
Original Assignee
Siemens Aktiengesellschaft
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Priority to PCT/RU2018/000750 priority Critical patent/WO2020101521A1/en
Publication of WO2020101521A1 publication Critical patent/WO2020101521A1/en

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Classifications

    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/396—Acquisition or processing of data for testing or for monitoring individual cells or groups of cells within a battery
    • G—PHYSICS
    • G01—MEASURING; TESTING
    • G01R—MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES
    • G01R31/00—Arrangements for testing electric properties; Arrangements for locating electric faults; Arrangements for electrical testing characterised by what is being tested not provided for elsewhere
    • G01R31/36—Arrangements for testing, measuring or monitoring the electrical condition of accumulators or electric batteries, e.g. capacity or state of charge [SoC]
    • G01R31/392—Determining battery ageing or deterioration, e.g. state of health

Definitions

  • the present invention generally relates to battery management, in particular to monitoring of battery state of health in long term.
  • electrochemical energy storage units are becoming more common, and they are subject to new requirements for increasing the uptime of electrical supply for power equipment.
  • battery systems, or batteries serve as the main electric power unit working under electric load and on the electric drive of the vehicle.
  • batteries are planned to be used in critical- mission areas. For example, currently companies are working on enabling passenger aircraft to fly with hybrid-electric propulsion systems. Additionally end customers would like to have batteries with low maintenance costs. Therefore knowledge about state and monitoring of the state of the battery system, for example, typically about state of charge (SOC) , depth of discharge (DOD) , state of health (SOH) , state of function (SOF) etc, is crucial in this case. So there is constant need for different methods and means for continuous monitoring of batteries to guarantee uninterruptible operation.
  • SOC state of charge
  • DOD depth of discharge
  • SOH state of health
  • SOF state of function
  • SOH state of health
  • Battery cell monitoring methods is usually categorized into two types - online and offline methods.
  • Online technique is about online measurement of voltage and current of the working battery cell to estimate battery cell parameters. It should be separately noted that the number of parameters of the battery system that can be measured while the battery system is in operation, is limited, in most cases to voltage and current. Typically measurement of voltage and current are taken for the whole battery system and/or for a particular battery cell of the battery system and / or for a battery module that is a pack of several battery cells. Also measuring of ambient environment parameters, for example, ambient temperature, and measuring of the temperature of the particular battery cell of the battery system is available while the battery system is in operation condition.
  • BMS battery management systems
  • Another category of battery cell monitoring methods is offline methods. Offline techniques are much more precise due to direct measurements of different parameters of the each battery cell of the battery system and the whole battery system. Significantly more parameters are available for off line measuring while the battery system and / or the battery cell of the battery system is out of operation.
  • the object of the present invention is to provide a new way of monitoring a battery cell state and a battery system state without interruption of functioning of the battery system.
  • a method for monitoring a battery cell state of a battery system without interruption of functioning of the battery system is presented.
  • the battery system comprises a plurality of battery cells connected to each other.
  • the method comprises at least an offline measurement part, which comprises the following steps. In the beginning the respective at least one battery cell of the battery system is disconnected from the battery system and replaced with the at least one backup battery cell. Further the offline measurement of at least one parameter of the disconnected at least one battery is performed. And finally the at least one backup battery is disconnected from the battery system and the previously disconnected at least one battery cell is connected back to the battery system. All such disconnections, connections and replacements are performed without any interruption of functioning of the battery system.
  • the method comprises further step within which an actual battery cell state of the at least one battery cell for which the offline measurement part of the method is determined. Such determination of the actual battery cell state is based on the offline measured at least one parameter .
  • a method for monitoring a battery system state without interruption of functioning of a battery system is presented.
  • the battery system comprises a plurality of battery cells connected to each other.
  • the method comprises the following steps.
  • At least one further parameter of the battery system is measured online while the battery system is in operation.
  • Such further parameters typically are voltage and current of the battery system.
  • an actual battery system state of the battery system is determined based on the at least one further parameter online measured at the previous step.
  • the online measurements of the at least one further parameter can be performed on permanent basis . Therefore the actual battery system state calculated based on such online measurements can be tracked in online regime. However such online based actual battery system state is usually not precise .
  • the offline measurement of at least one parameter is accomplished for at least one battery cell of the battery system.
  • Such offline measurement of the at least one parameter for the at least one battery cell of the battery system is accomplished as following.
  • the at least one battery cell of the battery system is disconnected from the battery system and replaced with the at least one backup battery cell. Further the offline measurement of at least one parameter of the disconnected at least one battery is performed. And finally the at least one backup battery is disconnected from the battery system and the previously disconnected at least one battery cell is connected back to the battery system. All such disconnections, connections and replacements are performed without any interruption of functioning of the battery system.
  • the actual battery system state determined earlier is adjusted based on the offline measured at least one parameter of the at least one battery cell measured within accomplishing the offline measurement part for the respective at least one battery cell.
  • a system for monitoring of a battery state without interruption of functioning of a battery system is presented.
  • the battery system comprises plurality of battery cells connected to each other.
  • Also the system comprises
  • At least one backup battery that is adopted to replace the at least one battery of the battery system;
  • a measurement device that is able to measure at least one parameter of the at least one battery cell of the battery system;
  • the system may be used to monitor a battery cell state of one battery cell of the battery system or to monitor the battery cell state of plurality battery cells of the battery system or to monitor the battery system state without interruption of functioning of the battery system .
  • offline measuring means that the measurements of parameters are fulfilled while the at least one battery cell is out of operation. In other words the at least one battery cell is disconnected from the battery system.
  • online measuring means that the measurements of further parameters are fulfilled while the at least one battery cell is connected to the battery system and the battery system is in operation and / or functioning.
  • the present invention is based on the insight that online and offline techniques have their advantages and disadvantages and more parameters for offline measuring to monitor state of the battery cell and / or the battery system are available. Therefore the better result in monitoring of the battery system state and the battery cell state can be achieved by combining both techniques. In particularly it is possible to disconnect a battery cell out of the battery system from time to time by replacing it with a backup battery and carry out direct (offline) measurement of parameters for further precise calculation of the battery cell state. Additionally accuracy of the online monitoring of the state of the battery systems and / or the battery cell based can be improved by using offline measured parameters. Further embodiments of the present invention are subject of the further sub-claims and of the following description, referring to the drawings.
  • the presence of an abnormal actual battery cell state of the at least one battery cell for which the offline measurement part of the method was accomplished is judged.
  • This feature allows monitoring whether the battery cell fits the battery system and the goals the battery system fulfills. Additionally in case the abnormal actual battery state of the disconnected battery is judged to be present, such battery cell can be replaced by other battery cell in timely manner. And therefore the failure of the battery system can be prevented.
  • the method for monitoring a battery cell state of a battery system without interruption of functioning of the battery system comprises steps for determining the battery cell state based on online measurement of at least one further parameter as following.
  • the online measurement of the at least one further parameter of the at least one battery cell of the battery system is accomplished.
  • Such measurements of the at least one further parameter are performed without any interruption of the battery system functioning while the at least one battery cell is operation in the battery system.
  • the determination of the actual battery cell state of the at least one battery cell is based on the online measurements of the at least one further parameter .
  • Online measurements of the at least one further parameter can be performed on permanent basis . Therefore the actual battery cell state calculated based on such online measurements can be tracked in online regime.
  • the offline measurement part of the method is accomplished for the respective at least one battery cell.
  • the respective at least one battery cell of the battery system is disconnected from the battery system and replaced with the at least one backup battery cell. Further the offline measurement of at least one parameter of the disconnected at least one battery is performed. And finally the at least one backup battery is disconnected from the battery system and the previously disconnected at least one battery cell is connected back to the battery system. All such disconnections, connections and replacements are performed without any interruption of functioning of the battery system.
  • This feature allows increasing the accuracy of the estimation of the battery cell state defined by means of online methods.
  • the actual battery cell state monitor by the present method is the state of health.
  • State of the Health is one of the important indicators of battery state.
  • State of health is a figure of merit of the condition of a battery (or a cell, or a battery pack / a battery system) , compared to its ideal conditions . Many applications require knowledge of the state of health.
  • the step of adjusting the actual battery systems state based on at least one parameter measured offline for at least one battery cell of the battery system is accomplished at a given time interval.
  • This feature allows providing monitoring of the battery cells of the battery system in economic manner and to lower maintenance costs due to several reasons. First such monitoring of the battery cell state is provided without interruption of functioning of the battery system. Additionally offline measurements typically are more expensive then online measurement.
  • the offline measurement can be performed always for the same at least one battery is disconnected for the offline measurement of the at least one parameter that is used for such adjustment of the actual battery system state.
  • the battery system comprises identical battery cells. Having the understanding of the battery cell state of one of them it is possible to judge about the battery cell states of other identical battery cells of the battery system. Therefore it is possible to adjust the battery system state having offline measured parameters of only one battery cell.
  • This feature allows providing monitoring of the battery cells of the battery system in economic manner and to lower maintenance costs due to several reasons .
  • a rotation of the at least one battery cell of the battery system to be disconnected for the offline measurement is provided according to a given order. In other words every time offline measurement is accomplished not only for the same at least one battery cell, but there is the given order specified by experts when and what battery cell of the battery system should be disconnected for further offline measurement .
  • Still battery cells even from one manufacturer and from one party can differ. Therefore it makes sense to rotate the battery cell for offline measurement. Also such disconnected battery cell can be easily replaced by new one in case some damage of the battery cell disconnected for offline measurement is discovered.
  • the actual battery system state monitor by the present method is the state of health.
  • State of the Health is one of the important indicators of battery state.
  • State of health is a figure of merit of the condition of a battery (or a cell, or a battery pack / a battery system), compared to its ideal conditions. Many applications require knowledge of the state of health.
  • the system may further comprise a control unit that that is adopted to perform method of monitoring a battery cell state without interruption of functioning of the battery system according to any of claims 1 to 5 , and / or method of monitoring a battery system state without interruption of functioning of the battery system according to any of claims 6 to 9.
  • FIG. 1 schematically illustrates a system for monitoring of a battery state without interruption of functioning of a battery system in accordance with the present invention
  • FIG. 2 illustrates the system for monitoring of a battery state without interruption of functioning of a battery system in accordance with the present invention while the offline measurement of the parameters of the at least one battery cell is performed;
  • FIG. 3 schematically illustrates a method for monitoring a battery cell state of a battery system without interruption of functioning of the battery system
  • FIG. 4 schematically illustrates an embodiment of the method for monitoring a battery cell state of a battery system without interruption of functioning of the battery system
  • FIG. 5 schematically illustrates other embodiment of the method for monitoring a battery cell state of a battery system without interruption of functioning of the battery system
  • FIG. 6 schematically illustrates a method for monitoring a battery system state of a battery system without interruption of functioning of the battery system
  • FIG 1 illustrates a system 1 for monitoring a battery state without interruption of functioning of a battery system 2.
  • the battery system 2 comprises plurality of battery cells 3, 3' connected to each other.
  • the plurality of the battery cells 3 of the battery system 2 can be in series and / or in parallel circuits.
  • system 1 comprises at least one backup battery 4 that is adopted to replace the at least one battery 3' of the battery system 2;
  • a measurement device 5 that is able to measure offline at least one parameter of the at least one battery cell 3' of the battery system 2 ;
  • system 1 can comprise a control unit 7 to perform different methods.
  • the system 1 may be used to monitor a battery cell state of one battery cell 3' of the battery system or to monitor the battery cell state of plurality battery cells 3' of the battery system 2 or to monitor the battery system state without interruption of functioning of the battery system 2.
  • Such monitoring is provided by replacing one or more battery cells 3' of the battery system 2 with one or more backup batteries 4 with further measurement of one or more parameters of such one or more battery cells 3' as it is described below.
  • Backup batteries are well-known. Usually the backup battery provides power when the primary source of power is unavailable. Backup batteries range from small single battery cells to retain clock, time and date in computers, up to large battery room facilities that power uninterruptible power supply systems for large data centers. Small backup batteries may be primary cells; rechargeable backup batteries are kept charged by the prime power supply.
  • the backup battery 4 may comprise one or more backup battery cells. In the ideal case the backup battery 4 should be like- for-like replacement of the at least one battery cell 3' . Also one or more backup batteries 4 can be used to replace the at least one battery cell 3' to keep the battery system 2 functioning .
  • the measurement device 5 is adopted to measure at least offline one or more parameters of the at least one battery cell 3, 3' of the battery system 2. Such measuring devices 5 are well known. There are different types of such devices. It can be a sensor, a function generator, a voltmeters, an amperemeters, a thermometer, etc. and / or any combination of such devices. Potentially the measuring device 5 can be used for online measurement of further parameters as well.
  • the switching arrangement 6 can be of different structure and nature .
  • the key feature of such switching arrangement 6 is the ability to replace the battery cell 3' of the battery system 2 with the at least one backup battery 4 and vise versa in such way that that the operation of the battery system 2 does not have to be interrupted.
  • offline measuring means that the measurements of parameters are fulfilled while the at least one battery cell 3 is out of operation. In other words the at least one battery cell 3' is disconnected from the battery system 2.
  • online measuring means that the measurements of further parameters are fulfilled while the at least one battery cell 3, 3' is connected to the battery system 2 and the battery system 2 is in operation arid / or functioning.
  • FIG 2 illustrates the system 1 while the offline measurement of the parameters of the at least one battery cell 3 is performed.
  • the at least one backup battery 4 is connected to the battery system 2 instead of the at least one battery cell 3' .
  • the battery system 2 is functioning the off-line measurements of the parameters of the at least one battery cell 3 are provided.
  • the switching arrangements 6 provides replacements of the at least one battery cell 3' with the at least one backup battery 4 and vise versa in such way that that the operation of the battery system 2 is not interrupted.
  • the control unit 7 can perform a method of monitoring a battery cell state without interruption of functioning of the battery system 2 and, additionally can manage measuring device 5, and / or switching arrangements 6.
  • FIG 3 shows a block diagram of the method 100 for monitoring a battery cell state of a battery system 2 without interruption of functioning of the battery system 2.
  • the battery system 2 comprises plurality of battery cells 3, 3' connected to each other.
  • the plurality of the battery cells 3, 3' of the battery system 2 can be in series and / or in parallel circuits.
  • the method 100 comprises at least an offline measurement part I.
  • the offline measurement part I of the method 100 comprises the following steps.
  • At a step 101 at least one battery cell 3' of the battery system 2 is disconnected from the battery system 2 and replaced with the at least one backup battery cell 4. And such disconnection and replacement are provided in such way that the operation of the battery system 3 is not interrupted.
  • Such disconnection and replacements can be provided by the switching arrangements 6 of the system 1 for monitoring a battery cell state without interruption of functioning of the battery system.
  • the battery system 2 may still work because of presence of the backup battery 4 as it shown on FIG 2.
  • the backup battery 4 should be like-for- like replacement of the at least one battery cell 3' .
  • the offline measurement of at least one parameter of the disconnected at least one battery 3' is performed.
  • One or more parameters can be measured within this step 102. Since the at least one battery 3' is disconnected from the battery system 2, parameters available only for offline measurement, can be measured. Typically such parameters are internal resistance and total capacity. Additionally the parameters available for online measurement also can be measured within this step 102, but with higher accuracy.
  • What parameters should be measured and how many parameters should be measured is defined by experts and depends on what state of the battery cell should be determined and monitored.
  • the at least one backup battery 4 should be disconnected from the battery system 2 and the previously disconnected at least one battery cell 3' is connected back to the battery system 2. Such replacement of the at least one backup battery 4 on the at least one battery cell 3' should be done in such way that the operation of the battery system 2 is not interrupted.
  • the method 100 further comprises the following steps.
  • an actual battery cell state of the at least one battery cell 3' for which the offline measurement part I of the method 100, in particularly steps 101 - 103, was accomplished, is determined. Such determination of the actual battery cell state is based on the offline measured at least one parameter, that was received as a result of the step 102.
  • the actual battery cell state can be calculated precisely based on known formulas and / or estimated by known methods . Also it should be noted that typically such determination - calculation and / or estimation - of the actual battery cell states can be done with higher accuracy when such calculations and estimations are based the parameters that are measured offline.
  • step 104 different battery cell states can be determined, for example, state of the health, state of the charge, state of discharge can be calculated or estimated with high preciseness . However what actual battery cell state is determined within this step 104 is defined by experts and based on what the at least one parameters to be measured offline .
  • the battery system 2 is able to function, in other words due to presence of the at least one backup battery 4 and its connection to the battery system 2, the battery system 2 can keep functioning.
  • the parameters based on which the actual battery cell state of the at least one battery cell 3 can be determined are measured. And such measurements are performed without interruption of functioning of the battery system 2.
  • a step 105 the judgment about the presence of an abnormal actual battery cell state of the at least one battery cell 3 for which the offline measurement, in particularly steps 101 - 103 were performed, can be made.
  • a given threshold is defined by experts and depends on the requirements specified by the battery system 2.
  • the step 104 of determining an actual battery cell state and the step 105 of judging the presence of abnormal actual battery cell state of the at least one battery cell 3' the offline measurement part I of the method 100 was accomplished can be accomplished before the step 103 of connecting back the disconnected within the step 102 battery cell 3' (shown on Fig 4) . In such case it the disconnected at least one battery cell 3' can be replaced by other battery cell if the abnormal actual battery cell state was detected within the step 105.
  • a step 201 of online measurement of the at least one further parameter of the at least one battery cell 3' of the battery system 2 is accomplished. Such measurements of the at least one further parameter are performed without any interruption of the battery system 2 functioning while the at least one battery cell 3' is operation in the battery system 2.
  • the list of further parameters that can be measured is rather limited because such measurements of the at least one further parameter of the at least one battery cell 3' are performed without disconnecting the at least one battery cell 3' from the battery system 2.
  • Such further parameters that can be measured are voltage, current, temperature of the battery cell 3' . These further parameters are measured by known equipment .
  • online measurements of such at least one further parameter can be accomplished for one battery cell 3' , several battery cells 3' or for the whole battery system 2.
  • the best result for the method 100 according the present invention is achieved when the online measurement within the step 201 and the offline measurement with the step 102 are performed for the same at least one battery cell 3' .
  • the determination of the actual battery cell state of the at least one battery cell 3 is based on the online measurements of the at least one further parameter that were performed with thin the step 201.
  • Online measurements of the at least one further parameter can be performed on permanent basis. Therefore the actual battery cell state calculated based on such online measurements can be tracked in online regime.
  • the offline measurement part I of the method 100 is accomplished for the respective at least one battery cell 3' .
  • the respective at least one battery cell 3' of the battery system 2 is disconnected from the battery system 2 and replaced with the at least one backup battery cell 4. Further at a step 102 the offline measurement of at least one parameter of the disconnected at least one battery 3' is performed. And finally at a step 103 the at least one backup battery 4 is disconnected from the battery system 2 and the previously disconnected at least one battery cell 3' is connected back to the battery system 2. All such disconnections, connections and replacements are performed without any interruption of functioning of the battery system 2.
  • the given time interval should be defined by experts. Such offline measurements can be accomplished with equal time intervals or arbitrary time intervals.
  • the actual battery cell state of the at least one battery cell 3' determined within the step 202 is adjusted based on the offline measured at least one parameter of the at least one battery cell 3' measured within accomplishing the offline measurement part I of the method 100 for the respective at least one battery cell 3' .
  • Such adjustments can be done in different modes. For example, having the offline measured parameters it is possible to calculate, for example, a coefficient used in a method for estimating the actual battery cell state based on online measured parameters. Therefore having such coefficient determined with high accuracy based on offline measurement it is possible to adjust the actual battery cell state determined based on online measurements.
  • FIG 6 shows a block diagram of the method 300 for monitoring a battery cell state of a battery system 2 without interruption of functioning of the battery system 2.
  • the battery system 2 comprises plurality of battery cells 3, 3' connected to each other.
  • the plurality of the battery cells 3 of the battery system 2 can be in series and / or in parallel circuits.
  • At a step 301 at least one further parameter of the battery system 2 is measured online while the battery system 2 is in operation.
  • Such further parameters typically are voltage and current of the battery system 2.
  • an actual battery system state of the battery system 2 is determined based on the at least one further parameter online measured at the step 301.
  • the online measurements of the at least one further parameter can be performed on permanent basis. Therefore the actual battery system state calculated based on such online measurements can be tracked in online regime. However such online based actual battery system state is usually not precise .
  • the offline measurement I of at least one parameter is accomplished for at least one battery cell 3' of the battery system 2.
  • Such offline measurement I of the at least one parameter for the at least one battery cell 3' of the battery system 2 is accomplished as following.
  • the at least one battery cell 3' of the battery system 2 is disconnected from the battery system 2 and replaced with the at least one backup battery cell 4.
  • the offline measurement of at least one parameter of the disconnected at least one battery 3' is performed.
  • the at least one backup battery 4 is disconnected from the battery system 2 and the previously disconnected at least one battery cell 3' is connected back to the battery system 2. All such disconnections, connections and replacements are performed without any interruption of functioning of the battery system 2.
  • the actual battery system state determined within the step 302 is adjusted based on the offline measured at least one parameter of the at least one battery cell 3' measured within accomplishing the offline measurement part I for the respective at least one battery cell 3' .
  • the step 303 of adjusting the actual battery systems state based on at least one parameter measured offline for at least one battery cell of the battery system is accomplished at a given time intervals.
  • the given time interval should be defined by experts. Such offline measurements can be accomplished with equal time intervals or arbitrary time intervals .
  • the offline measurement I within the step 303 can be performed always for the same at least one battery 3' is disconnected for the off-line measurement of the at least one parameter that is used for such adjustment of the actual battery system state.
  • a rotation of the at least one battery cell 3' of the battery system 2 to be disconnected for the offline measurement I is provided according to a given order.
  • every time offline measurement I is accomplished not only for the same at least one battery cell 3' , but there is the given order specified by experts when and what battery cell 3' of the battery system should be disconnected for further offline measurement I.

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Abstract

In an aspect of the present invention, a method for monitoring a battery cell state of a battery system without interruption of functioning of the battery system is presented. Wherein the battery system comprises a plurality of battery cells connected to each other. The method comprises at least an offline measurement part, which comprises the following steps. In the beginning the respective at least one battery cell of the battery system is disconnected from the battery system and replaced with the at least one backup battery cell. Further the offline measurement of at least one parameter of the disconnected at least one battery is performed. And finally the at least one backup battery is disconnected from the battery system and the previously disconnected at least one battery cell is connected back to the battery system. All such disconnections, connections and replacements are performed without any interruption of functioning of the battery system. Finally the method comprises further step within which an actual battery cell state of the at least one battery cell for which the offline measurement part of the method is determined. Such determination of the actual battery cell state is based on the offline measured at least one parameter.

Description

METHOD AND SYSTEM FOR MONITORING A BATTERY CELL STATE AND A BATTERY SYSTEM STATE WITHOUT INTERRUPTION OF FUNCTIONING OF A
BATTERY SYSTEM
The present invention generally relates to battery management, in particular to monitoring of battery state of health in long term.
The use of electrochemical energy storage units is becoming more common, and they are subject to new requirements for increasing the uptime of electrical supply for power equipment. In some cases, battery systems, or batteries serve as the main electric power unit working under electric load and on the electric drive of the vehicle.
Besides using them as storage in smart grids, electrocars and quadrocopters , batteries are planned to be used in critical- mission areas. For example, currently companies are working on enabling passenger aircraft to fly with hybrid-electric propulsion systems. Additionally end customers would like to have batteries with low maintenance costs. Therefore knowledge about state and monitoring of the state of the battery system, for example, typically about state of charge (SOC) , depth of discharge (DOD) , state of health (SOH) , state of function (SOF) etc, is crucial in this case. So there is constant need for different methods and means for continuous monitoring of batteries to guarantee uninterruptible operation.
One of the important indicators of battery state is state of health (SOH) , which is a figure of merit of the condition of a battery (or a cell, or a battery pack / a battery system) , compared to its ideal conditions. The units of SOH are percent points (100% = the battery's conditions match the battery's specifications). Typically, a battery's SOH will be 100% at the time of manufacture and will decrease over time and use .
Online and offline methods can be used for SOH' s estimation. Based on knowledge of the SoH of a given battery it is possible to define whether the present battery conditions make it suitable for that particular application, and an estimate can be made of the battery's useful lifetime in that application.
Battery cell monitoring methods is usually categorized into two types - online and offline methods.
Online technique is about online measurement of voltage and current of the working battery cell to estimate battery cell parameters. It should be separately noted that the number of parameters of the battery system that can be measured while the battery system is in operation, is limited, in most cases to voltage and current. Typically measurement of voltage and current are taken for the whole battery system and/or for a particular battery cell of the battery system and / or for a battery module that is a pack of several battery cells. Also measuring of ambient environment parameters, for example, ambient temperature, and measuring of the temperature of the particular battery cell of the battery system is available while the battery system is in operation condition.
Online monitoring of the battery system state is mainly done by means of electrical battery circuit modeling and Kalman filtering. However, all kind of online techniques tend to diverge from true values. For example, coefficients of Kalman filters have to be manually attuned for each kind of batteries. There is just no way how to automatize this process at present. Therefore it is unlikely that such solution in able to work stable for three or more years without interference.
Multiple approaches exist how to provide online monitoring battery cells in a battery system, and typically this function is included into functions of battery management systems (BMS) , that are used to manage battery systems. In general, BMS performs a set of function such as protecting the battery systems from operating outside its safe operating area, monitoring its state, calculating secondary data, reporting that data, controlling its environment, authenticating and balancing as well.
Another category of battery cell monitoring methods is offline methods. Offline techniques are much more precise due to direct measurements of different parameters of the each battery cell of the battery system and the whole battery system. Significantly more parameters are available for off line measuring while the battery system and / or the battery cell of the battery system is out of operation.
The basic disadvantage they have is that one or more battery cells of the battery system or the whole battery system have to be disconnected for some time. That is why this approach is used in most case in laboratory studies .
Taking into account all mentioned above it should be noted that there is an obvious need to monitor state of a battery system that comprises a plurality of battery cells without interruption of functioning of the battery system and to provide such battery system state monitoring with higher accuracy to achieve new level of efficiency for predictive maintenance .
Accordingly, the object of the present invention is to provide a new way of monitoring a battery cell state and a battery system state without interruption of functioning of the battery system.
The object of the present invention is achieved
by a method for monitoring a battery cell state of a battery system without interruption of functioning of the battery system as defined in claim 1,
by a method for monitoring a battery system state without interruption of functioning of the battery system a smart battery system as defined in claim 5, and
by a system for monitoring of a battery cell state without interruption of functioning of a battery system as defined in claim 10.
Advantageous embodiments of the present invention are provided in dependent claims. Features of claims 1, 5, 10 can be combined with features of dependent claims, and features of dependent claims can be combined together. In an aspect of the present invention, a method for monitoring a battery cell state of a battery system without interruption of functioning of the battery system is presented. Wherein the battery system comprises a plurality of battery cells connected to each other. The method comprises at least an offline measurement part, which comprises the following steps. In the beginning the respective at least one battery cell of the battery system is disconnected from the battery system and replaced with the at least one backup battery cell. Further the offline measurement of at least one parameter of the disconnected at least one battery is performed. And finally the at least one backup battery is disconnected from the battery system and the previously disconnected at least one battery cell is connected back to the battery system. All such disconnections, connections and replacements are performed without any interruption of functioning of the battery system.
Finally the method comprises further step within which an actual battery cell state of the at least one battery cell for which the offline measurement part of the method is determined. Such determination of the actual battery cell state is based on the offline measured at least one parameter .
In other aspect of the present invention a method for monitoring a battery system state without interruption of functioning of a battery system is presented. The battery system comprises a plurality of battery cells connected to each other. According to the present invention the method comprises the following steps.
At least one further parameter of the battery system is measured online while the battery system is in operation. Such further parameters typically are voltage and current of the battery system.
Further an actual battery system state of the battery system is determined based on the at least one further parameter online measured at the previous step. The online measurements of the at least one further parameter can be performed on permanent basis . Therefore the actual battery system state calculated based on such online measurements can be tracked in online regime. However such online based actual battery system state is usually not precise .
Therefore in accordance with the present invention while the online measurements are performed on regular basis, from time to time with a given time interval the offline measurement of at least one parameter is accomplished for at least one battery cell of the battery system.
Such offline measurement of the at least one parameter for the at least one battery cell of the battery system is accomplished as following. The at least one battery cell of the battery system is disconnected from the battery system and replaced with the at least one backup battery cell. Further the offline measurement of at least one parameter of the disconnected at least one battery is performed. And finally the at least one backup battery is disconnected from the battery system and the previously disconnected at least one battery cell is connected back to the battery system. All such disconnections, connections and replacements are performed without any interruption of functioning of the battery system.
After that the actual battery system state determined earlier is adjusted based on the offline measured at least one parameter of the at least one battery cell measured within accomplishing the offline measurement part for the respective at least one battery cell.
In other aspect of the present invention a system for monitoring of a battery state without interruption of functioning of a battery system is presented. Wherein the battery system comprises plurality of battery cells connected to each other.
Also the system comprises
at least one backup battery that is adopted to replace the at least one battery of the battery system; a measurement device that is able to measure at least one parameter of the at least one battery cell of the battery system;
and a switching arrangement that is adopted to replace the at least one battery cell of the battery system with the at least one backup battery and vise versa in such way that that the operation of the battery system does not have to be interrupted .
The system may be used to monitor a battery cell state of one battery cell of the battery system or to monitor the battery cell state of plurality battery cells of the battery system or to monitor the battery system state without interruption of functioning of the battery system .
Hereinafter "offline measuring" means that the measurements of parameters are fulfilled while the at least one battery cell is out of operation. In other words the at least one battery cell is disconnected from the battery system.
Hereinafter "online measuring" means that the measurements of further parameters are fulfilled while the at least one battery cell is connected to the battery system and the battery system is in operation and / or functioning.
The present invention is based on the insight that online and offline techniques have their advantages and disadvantages and more parameters for offline measuring to monitor state of the battery cell and / or the battery system are available. Therefore the better result in monitoring of the battery system state and the battery cell state can be achieved by combining both techniques. In particularly it is possible to disconnect a battery cell out of the battery system from time to time by replacing it with a backup battery and carry out direct (offline) measurement of parameters for further precise calculation of the battery cell state. Additionally accuracy of the online monitoring of the state of the battery systems and / or the battery cell based can be improved by using offline measured parameters. Further embodiments of the present invention are subject of the further sub-claims and of the following description, referring to the drawings.
In a possible embodiment of the method for monitoring a battery cell state of a battery system without interruption of functioning of the battery system, the presence of an abnormal actual battery cell state of the at least one battery cell for which the offline measurement part of the method was accomplished, is judged. Wherein the abnormal actual battery cell state judged to be present when the actual battery cell state of the corresponding at least one battery cell is below a given threshold.
This feature allows monitoring whether the battery cell fits the battery system and the goals the battery system fulfills. Additionally in case the abnormal actual battery state of the disconnected battery is judged to be present, such battery cell can be replaced by other battery cell in timely manner. And therefore the failure of the battery system can be prevented.
According to the embodiment of the present invention the method for monitoring a battery cell state of a battery system without interruption of functioning of the battery system, the method comprises steps for determining the battery cell state based on online measurement of at least one further parameter as following. The online measurement of the at least one further parameter of the at least one battery cell of the battery system is accomplished. Such measurements of the at least one further parameter are performed without any interruption of the battery system functioning while the at least one battery cell is operation in the battery system. Further the determination of the actual battery cell state of the at least one battery cell is based on the online measurements of the at least one further parameter .
Online measurements of the at least one further parameter can be performed on permanent basis . Therefore the actual battery cell state calculated based on such online measurements can be tracked in online regime.
However such online based actual battery cell state of the at least one battery cell is usually not precise. Contrary based on offline measurements of the at least one parameter of the at least one battery cell it is possible to calculate actual battery cell state with high level of preciseness.
Therefore in accordance with the present invention while the online measurements are performed on regular basis, from time to time with a given time interval the offline measurement part of the method is accomplished for the respective at least one battery cell.
As it was described above the respective at least one battery cell of the battery system is disconnected from the battery system and replaced with the at least one backup battery cell. Further the offline measurement of at least one parameter of the disconnected at least one battery is performed. And finally the at least one backup battery is disconnected from the battery system and the previously disconnected at least one battery cell is connected back to the battery system. All such disconnections, connections and replacements are performed without any interruption of functioning of the battery system.
This feature allows increasing the accuracy of the estimation of the battery cell state defined by means of online methods.
In a possible embodiment of the method for monitoring a battery cell state of a battery system without interruption of functioning of the battery system, the actual battery cell state monitor by the present method is the state of health.
State of the Health (SOH) is one of the important indicators of battery state. State of health (SOH) is a figure of merit of the condition of a battery (or a cell, or a battery pack / a battery system) , compared to its ideal conditions . Many applications require knowledge of the state of health.
In a possible embodiment of the method for monitoring a battery system state without interruption of functioning of a battery system, the step of adjusting the actual battery systems state based on at least one parameter measured offline for at least one battery cell of the battery system is accomplished at a given time interval.
This feature allows providing monitoring of the battery cells of the battery system in economic manner and to lower maintenance costs due to several reasons. First such monitoring of the battery cell state is provided without interruption of functioning of the battery system. Additionally offline measurements typically are more expensive then online measurement.
In enhanced embodiment of the method for monitoring a battery system state without interruption of functioning of a battery system, the offline measurement can be performed always for the same at least one battery is disconnected for the offline measurement of the at least one parameter that is used for such adjustment of the actual battery system state.
In fact in case the battery system comprises identical battery cells. Having the understanding of the battery cell state of one of them it is possible to judge about the battery cell states of other identical battery cells of the battery system. Therefore it is possible to adjust the battery system state having offline measured parameters of only one battery cell.
This feature allows providing monitoring of the battery cells of the battery system in economic manner and to lower maintenance costs due to several reasons .
In enhanced embodiment of the method for monitoring a battery system state without interruption of functioning of a battery system, a rotation of the at least one battery cell of the battery system to be disconnected for the offline measurement is provided according to a given order. In other words every time offline measurement is accomplished not only for the same at least one battery cell, but there is the given order specified by experts when and what battery cell of the battery system should be disconnected for further offline measurement .
Still battery cells even from one manufacturer and from one party can differ. Therefore it makes sense to rotate the battery cell for offline measurement. Also such disconnected battery cell can be easily replaced by new one in case some damage of the battery cell disconnected for offline measurement is discovered.
In other possible embodiment of the method for monitoring a battery system state without interruption of functioning of a battery system, the actual battery system state monitor by the present method is the state of health.
State of the Health (SOH) is one of the important indicators of battery state. State of health (SOH) is a figure of merit of the condition of a battery (or a cell, or a battery pack / a battery system), compared to its ideal conditions. Many applications require knowledge of the state of health.
In enhanced embodiment of the system for monitoring of a battery state without interruption of functioning of a battery system, the system may further comprise a control unit that that is adopted to perform method of monitoring a battery cell state without interruption of functioning of the battery system according to any of claims 1 to 5 , and / or method of monitoring a battery system state without interruption of functioning of the battery system according to any of claims 6 to 9.
For more complete understanding of the present invention and advantages thereof, reference is now made to the following description taken in accompanying drawings . The invention is explained in more details below using exemplary embodiments which are specified in the schematic figures of the drawings, in which:
FIG. 1 schematically illustrates a system for monitoring of a battery state without interruption of functioning of a battery system in accordance with the present invention; FIG. 2 illustrates the system for monitoring of a battery state without interruption of functioning of a battery system in accordance with the present invention while the offline measurement of the parameters of the at least one battery cell is performed;
FIG. 3 schematically illustrates a method for monitoring a battery cell state of a battery system without interruption of functioning of the battery system;
FIG. 4 schematically illustrates an embodiment of the method for monitoring a battery cell state of a battery system without interruption of functioning of the battery system;
FIG. 5 schematically illustrates other embodiment of the method for monitoring a battery cell state of a battery system without interruption of functioning of the battery system;
FIG. 6 schematically illustrates a method for monitoring a battery system state of a battery system without interruption of functioning of the battery system;
Various embodiments are described with reference to the drawings, wherein like reference numerals are used to refer to like elements throughout. In the following description, for purpose of explanation, numerous specific details are set forth in order to provide a thorough understanding of one or more embodiments. It may be noted that the illustrated embodiments are intended to explain, and not to limit the invention. It may be evident that such embodiments may be practiced without these specific details.
FIG 1 illustrates a system 1 for monitoring a battery state without interruption of functioning of a battery system 2.
Wherein the battery system 2 comprises plurality of battery cells 3, 3' connected to each other. The plurality of the battery cells 3 of the battery system 2 can be in series and / or in parallel circuits.
Also the system 1 comprises at least one backup battery 4 that is adopted to replace the at least one battery 3' of the battery system 2;
a measurement device 5 that is able to measure offline at least one parameter of the at least one battery cell 3' of the battery system 2 ;
and a switching arrangement 6 that is adopted to replace the at least one battery cell 3' of the battery system 2 with the at least one backup battery 4 and vise versa in such way that that the operation of the battery system 2 does not have to be interrupted.
Additionally the system 1 can comprise a control unit 7 to perform different methods.
The system 1 may be used to monitor a battery cell state of one battery cell 3' of the battery system or to monitor the battery cell state of plurality battery cells 3' of the battery system 2 or to monitor the battery system state without interruption of functioning of the battery system 2.
Such monitoring is provided by replacing one or more battery cells 3' of the battery system 2 with one or more backup batteries 4 with further measurement of one or more parameters of such one or more battery cells 3' as it is described below.
Backup batteries are well-known. Usually the backup battery provides power when the primary source of power is unavailable. Backup batteries range from small single battery cells to retain clock, time and date in computers, up to large battery room facilities that power uninterruptible power supply systems for large data centers. Small backup batteries may be primary cells; rechargeable backup batteries are kept charged by the prime power supply.
The backup battery 4 may comprise one or more backup battery cells. In the ideal case the backup battery 4 should be like- for-like replacement of the at least one battery cell 3' . Also one or more backup batteries 4 can be used to replace the at least one battery cell 3' to keep the battery system 2 functioning . The measurement device 5 is adopted to measure at least offline one or more parameters of the at least one battery cell 3, 3' of the battery system 2. Such measuring devices 5 are well known. There are different types of such devices. It can be a sensor, a function generator, a voltmeters, an amperemeters, a thermometer, etc. and / or any combination of such devices. Potentially the measuring device 5 can be used for online measurement of further parameters as well.
The switching arrangement 6 can be of different structure and nature . However the key feature of such switching arrangement 6 is the ability to replace the battery cell 3' of the battery system 2 with the at least one backup battery 4 and vise versa in such way that that the operation of the battery system 2 does not have to be interrupted.
Hereinafter "offline measuring" means that the measurements of parameters are fulfilled while the at least one battery cell 3 is out of operation. In other words the at least one battery cell 3' is disconnected from the battery system 2.
Hereinafter "online measuring" means that the measurements of further parameters are fulfilled while the at least one battery cell 3, 3' is connected to the battery system 2 and the battery system 2 is in operation arid / or functioning.
FIG 2 illustrates the system 1 while the offline measurement of the parameters of the at least one battery cell 3 is performed. To keep the battery system 2 is in operation and do not interrupt it's functioning the at least one backup battery 4 is connected to the battery system 2 instead of the at least one battery cell 3' . While the battery system 2 is functioning the off-line measurements of the parameters of the at least one battery cell 3 are provided. As soon as all required offline measurements are performed the at least one battery cell 3' is connected to the battery system 2 by means of the switching arrangements 6. The switching arrangements 6 provides replacements of the at least one battery cell 3' with the at least one backup battery 4 and vise versa in such way that that the operation of the battery system 2 is not interrupted. The control unit 7 can perform a method of monitoring a battery cell state without interruption of functioning of the battery system 2 and, additionally can manage measuring device 5, and / or switching arrangements 6.
Further the details of the system 1 for monitoring a battery cell state without interruption of functioning of the battery system 2 will be described together with the description of the method for monitoring a battery cell state of the battery system 2 and a battery system state of the battery system 2 without interruption of functioning of the battery system 2.
FIG 3 shows a block diagram of the method 100 for monitoring a battery cell state of a battery system 2 without interruption of functioning of the battery system 2.
As it was described above the battery system 2 comprises plurality of battery cells 3, 3' connected to each other. The plurality of the battery cells 3, 3' of the battery system 2 can be in series and / or in parallel circuits.
The method 100 comprises at least an offline measurement part I. Wherein the offline measurement part I of the method 100 comprises the following steps.
At a step 101 at least one battery cell 3' of the battery system 2 is disconnected from the battery system 2 and replaced with the at least one backup battery cell 4. And such disconnection and replacement are provided in such way that the operation of the battery system 3 is not interrupted.
Such disconnection and replacements can be provided by the switching arrangements 6 of the system 1 for monitoring a battery cell state without interruption of functioning of the battery system.
While the at least one battery cell 3 of the battery system 2 is disconnected from the battery system 2 the battery system 2 may still work because of presence of the backup battery 4 as it shown on FIG 2.
In the ideal case the backup battery 4 should be like-for- like replacement of the at least one battery cell 3' . At a step 102 the offline measurement of at least one parameter of the disconnected at least one battery 3' is performed. One or more parameters can be measured within this step 102. Since the at least one battery 3' is disconnected from the battery system 2, parameters available only for offline measurement, can be measured. Typically such parameters are internal resistance and total capacity. Additionally the parameters available for online measurement also can be measured within this step 102, but with higher accuracy.
It is possible to measure one or more parameters. What parameters should be measured and how many parameters should be measured is defined by experts and depends on what state of the battery cell should be determined and monitored.
As soon as all necessary offline measurements are done, at a step 103 the at least one backup battery 4 should be disconnected from the battery system 2 and the previously disconnected at least one battery cell 3' is connected back to the battery system 2. Such replacement of the at least one backup battery 4 on the at least one battery cell 3' should be done in such way that the operation of the battery system 2 is not interrupted.
Such smooth functioning of the battery system 2 during these connections and replacements can be provided by the switching arrangement 6.
The method 100 further comprises the following steps.
At a step 104 an actual battery cell state of the at least one battery cell 3' for which the offline measurement part I of the method 100, in particularly steps 101 - 103, was accomplished, is determined. Such determination of the actual battery cell state is based on the offline measured at least one parameter, that was received as a result of the step 102.
Depending on what actual battery cell state should be determined and depending on what at least one parameter was measured offline, the actual battery cell state can be calculated precisely based on known formulas and / or estimated by known methods . Also it should be noted that typically such determination - calculation and / or estimation - of the actual battery cell states can be done with higher accuracy when such calculations and estimations are based the parameters that are measured offline.
Within this step 104 different battery cell states can be determined, for example, state of the health, state of the charge, state of discharge can be calculated or estimated with high preciseness . However what actual battery cell state is determined within this step 104 is defined by experts and based on what the at least one parameters to be measured offline .
Also in case more than one battery cell 3' was disconnected, it is possible to measure the parameters of each and every disconnected battery cells 3' and / or the parameters for a pack of such disconnected battery cells 3' . Having these parameters it is possible to determine actual state of each and every disconnected battery cells 3 and / or of the whole pack of such plurality of disconnected battery cells 3' .
Still it should be separately noted that during all these measurements the battery system 2 is able to function, in other words due to presence of the at least one backup battery 4 and its connection to the battery system 2, the battery system 2 can keep functioning.
As a result of performing of the offline measurement part I of the method 100 the parameters based on which the actual battery cell state of the at least one battery cell 3 can be determined are measured. And such measurements are performed without interruption of functioning of the battery system 2.
Additionally, at a step 105 the judgment about the presence of an abnormal actual battery cell state of the at least one battery cell 3 for which the offline measurement, in particularly steps 101 - 103 were performed, can be made. The abnormal actual battery cell state judged to be present when the actual battery cell state of the corresponding at least one battery cell 3' is below a given threshold. Such given threshold is defined by experts and depends on the requirements specified by the battery system 2.
The step 104 of determining an actual battery cell state and the step 105 of judging the presence of abnormal actual battery cell state of the at least one battery cell 3' the offline measurement part I of the method 100 was accomplished can be accomplished before the step 103 of connecting back the disconnected within the step 102 battery cell 3' (shown on Fig 4) . In such case it the disconnected at least one battery cell 3' can be replaced by other battery cell if the abnormal actual battery cell state was detected within the step 105.
According to the embodiment of the present invention the method 100 as shown on FIG 5 a step 201 of online measurement of the at least one further parameter of the at least one battery cell 3' of the battery system 2 is accomplished. Such measurements of the at least one further parameter are performed without any interruption of the battery system 2 functioning while the at least one battery cell 3' is operation in the battery system 2.
The list of further parameters that can be measured is rather limited because such measurements of the at least one further parameter of the at least one battery cell 3' are performed without disconnecting the at least one battery cell 3' from the battery system 2.
Typically such further parameters that can be measured are voltage, current, temperature of the battery cell 3' . These further parameters are measured by known equipment .
Also online measurements of such at least one further parameter can be accomplished for one battery cell 3' , several battery cells 3' or for the whole battery system 2. However the best result for the method 100 according the present invention is achieved when the online measurement within the step 201 and the offline measurement with the step 102 are performed for the same at least one battery cell 3' .
Further at a step 202 the determination of the actual battery cell state of the at least one battery cell 3 is based on the online measurements of the at least one further parameter that were performed with thin the step 201.
Online measurements of the at least one further parameter can be performed on permanent basis. Therefore the actual battery cell state calculated based on such online measurements can be tracked in online regime.
However such online based actual battery cell state of the at least one battery cell 3' is usually not precise. Contrary based on offline measurements of the at least one parameter of the at least one battery cell 3' it is possible to calculate actual battery cell state with high level of preciseness .
Therefore in accordance with the present invention while the online measurements are performed on regular basis, from time to time with a given time interval the offline measurement part I of the method 100 is accomplished for the respective at least one battery cell 3' .
As it was described above at a step 101 the respective at least one battery cell 3' of the battery system 2 is disconnected from the battery system 2 and replaced with the at least one backup battery cell 4. Further at a step 102 the offline measurement of at least one parameter of the disconnected at least one battery 3' is performed. And finally at a step 103 the at least one backup battery 4 is disconnected from the battery system 2 and the previously disconnected at least one battery cell 3' is connected back to the battery system 2. All such disconnections, connections and replacements are performed without any interruption of functioning of the battery system 2.
The given time interval should be defined by experts. Such offline measurements can be accomplished with equal time intervals or arbitrary time intervals.
At a step 203 the actual battery cell state of the at least one battery cell 3' determined within the step 202 is adjusted based on the offline measured at least one parameter of the at least one battery cell 3' measured within accomplishing the offline measurement part I of the method 100 for the respective at least one battery cell 3' .
Such adjustments can be done in different modes. For example, having the offline measured parameters it is possible to calculate, for example, a coefficient used in a method for estimating the actual battery cell state based on online measured parameters. Therefore having such coefficient determined with high accuracy based on offline measurement it is possible to adjust the actual battery cell state determined based on online measurements.
Using described above method 100 it is possible to monitor the state of the health of the at least one battery cell 3' of the battery system 2 without interruption of functioning of the battery system 2.
FIG 6 shows a block diagram of the method 300 for monitoring a battery cell state of a battery system 2 without interruption of functioning of the battery system 2.
The battery system 2 comprises plurality of battery cells 3, 3' connected to each other. The plurality of the battery cells 3 of the battery system 2 can be in series and / or in parallel circuits.
According the method 300 at a step 301 at least one further parameter of the battery system 2 is measured online while the battery system 2 is in operation. Such further parameters typically are voltage and current of the battery system 2.
Further at a step 302 an actual battery system state of the battery system 2 is determined based on the at least one further parameter online measured at the step 301.
The online measurements of the at least one further parameter can be performed on permanent basis. Therefore the actual battery system state calculated based on such online measurements can be tracked in online regime. However such online based actual battery system state is usually not precise .
Therefore in accordance with the present invention while the online measurements are performed on regular basis, from time to time with a given time interval the offline measurement I of at least one parameter is accomplished for at least one battery cell 3' of the battery system 2.
Such offline measurement I of the at least one parameter for the at least one battery cell 3' of the battery system 2 is accomplished as following. At a step 101 the at least one battery cell 3' of the battery system 2 is disconnected from the battery system 2 and replaced with the at least one backup battery cell 4. Further at a step 102 the offline measurement of at least one parameter of the disconnected at least one battery 3' is performed. And finally at a step 103 the at least one backup battery 4 is disconnected from the battery system 2 and the previously disconnected at least one battery cell 3' is connected back to the battery system 2. All such disconnections, connections and replacements are performed without any interruption of functioning of the battery system 2.
After that at a step 303, the actual battery system state determined within the step 302 is adjusted based on the offline measured at least one parameter of the at least one battery cell 3' measured within accomplishing the offline measurement part I for the respective at least one battery cell 3' .
The step 303 of adjusting the actual battery systems state based on at least one parameter measured offline for at least one battery cell of the battery system is accomplished at a given time intervals. The given time interval should be defined by experts. Such offline measurements can be accomplished with equal time intervals or arbitrary time intervals .
The offline measurement I within the step 303 can be performed always for the same at least one battery 3' is disconnected for the off-line measurement of the at least one parameter that is used for such adjustment of the actual battery system state.
Alternatively a rotation of the at least one battery cell 3' of the battery system 2 to be disconnected for the offline measurement I is provided according to a given order. In other words every time offline measurement I is accomplished not only for the same at least one battery cell 3' , but there is the given order specified by experts when and what battery cell 3' of the battery system should be disconnected for further offline measurement I.
Using described above method 300 it is possible to monitor the state of the health of the battery system 2 without interruption of functioning of the battery system 2.
While the present invention has been described in detail with the reference to certain embodiments, it should be appreciated that the present invention is not limited to those precise embodiments. Rather, in view of the present disclosure which describes exemplary modes for practicing the invention, many modifications and variations would present themselves to those skilled in the art without departing from the scope and spirit of this invention. The scope of the invention is, therefore, indicated by the following claims rather than by the foregoing description. All changes, modifications, and variations coming within the meaning and range of equivalency of the claims are to be considered within their scope.
Reference numerals
1 - system
2 - battery system
3, 3' - battery cell
4 - backup battery
5 - measurement device
6 - switching arrangement
7 - control unit
100, 300 - method
101 - 103, 201 - 203, 301 - 303 - steps of the method
t

Claims

PATENT CLAIMS
1. A method (100) for monitoring a battery cell state of a battery system (2) without interruption of functioning of the battery system (2) ,
wherein the battery system (2) comprises a plurality of battery cells (3, 3') connected to each other,
the method (100) comprises at least an offline measurement part (I) , wherein the offline measurement part (I) comprises a step of disconnecting (101) at least one battery cell (3') of the battery system (2) and replacing it with at least one backup battery (4) , wherein such disconnection and replacement are provided in such way that the operation of the battery system (2) is not interrupted,
a step of offline measuring (102) at least one parameter of the disconnected at least one battery cell (3') of the battery system (2) , and
a step of replacing back (103) the at least one backup battery (4) on the disconnected at least one battery cell (3') by disconnecting the at least one backup battery (4) from the battery system (2) and connecting back the disconnected at least one battery cell (3'), wherein such disconnection and connection are provided in such way that the operation of the battery system (2) is not interrupted, the method (100) further comprises
a step of determining (104) an actual battery cell state of the at least one battery cell (3') for which the offline measurement part (I) of the method (100) was accomplished, wherein such determination of the actual battery cell state is based on the offline measured at least one parameter .
2. The method (100) of claim 1, wherein the method (100) further comprises
a step of judging (105) of the presence of an abnormal actual battery cell state of the at least one battery cell (3') for which the offline measurement part (I) of the method (100) was accomplished,
wherein the abnormal actual battery cell state judged to be present when the actual battery cell state of the corresponding at least one battery cell 3' is below a given threshold.
3. The method (100) of claim 1 wherein the method (100) comprises
a step of online measuring (201) the at least one further parameter of the at least one battery cell (3' ) of the battery system (2) wherein such measurement of the at least one further parameter is accomplished in such way that the operation of the battery system (2) is not interrupted, a step (202) of determining the actual battery cell state of the at least one battery cell 3' is based on the online measured at least one further parameter,
a step (203) of adjusting the actual battery cell state of the at least one battery cell (3' ) based on the offline measured at least one parameter of the at least one battery cell (3' ) measured within accomplishing the offline measurement part (I) of the method (100) for the respective least one battery cell 3' ,
wherein the offline measurement of the at least one parameter of the at least one battery cell ( 3 ) in accordance with the offline measurement part (I) of the method (100) is accomplished with a given time interval.
4. The method (100) of any of claims 1 to 3, wherein the actual battery cell state is the state of the health of the at least one battery cell (3') .
5. A method (300) for monitoring a battery system state without interruption of functioning of a battery system (2), wherein the battery system (2) comprises a plurality of battery cells (3, 3' ) connected to each other,
the method (300) comprises: a step of online measuring (301) at least one further parameter of the battery system (2) ,
a step of determining (302) an actual battery system state based on the online measured at least one further parameter, a step of adjusting (303) the actual battery systems state based on at least one parameter measured offline for at least one battery cell (3') of the battery system (2) ,
wherein the offline measurement (I) of the at least one parameter for the at least one battery cell (3' ) is accomplished as the following:
disconnecting (101) the at least one battery cell (3') of the battery system (2) and replacing it with at least one backup battery (4), wherein such disconnection and replacement are provided in such way that the operation of the battery system (2) is not interrupted, offline measuring (102) the at least one parameter of the disconnected at least one battery cell (3' ) of the battery system (2) ,
replacing back (103) the at least one backup battery (4) on the disconnected at least one battery cell (3' ) by disconnecting the at least one backup battery (4) from the battery system (2) and connecting back the disconnected at least one battery cell (3' ) , wherein such disconnection and connection are provided in such way that the operation of the battery system (2) is not interrupted.
6. The method (300) of claim 5 wherein
the step of adjusting (300) the actual battery systems state based on at least one parameter measured offline for at least one battery cell (3' ) of the battery system (2) is accomplished at a given time interval.
7. The method (300) of any of claims 6, wherein each time when the step of adjusting (303) the actual battery systems state is accomplished at the given time interval, always the same at least one battery cell (3') is disconnected for the offline measurement (I) of the at least one parameter that is used for such adjustment of the actual battery system state.
8. The method (300) of claim 6, wherein
each time when the step of adjusting the actual battery systems state is accomplished at the given time interval, a rotation of the at least one battery cell (3') of the battery system (2) to be disconnected for the offline measurement (I) is provided according to a given order.
9. The method (300) of any of claims 1 to 9, wherein the battery system state is the state of the health of the battery cell system.
10. A system (1) for monitoring of a battery state without interruption of functioning of a battery system (2) , wherein the battery system (2) comprises a plurality of battery cells (3, 3') connected to each other,
the system (1) comprises
at least one backup battery (4) that is adopted to replace the at least one battery cell (3') of the battery system (2), a measurement device (5) that is able to measure at least one parameter of the at least one battery cell (3') of the battery system (2) ,
a switching arrangement (6) that is adopted to replace the at least one battery cell (3') of the battery system (2) with the at least one backup battery (4) and vise versa in such way that that the operation of the battery system (2) does not have to be interrupted.
11. The system (1) of claim 10,
wherein the battery state monitored is the battery cell state, and wherein the system (1) further comprises a control unit (7) that is adopted to perform method (100) of monitoring a battery cell state without interruption of functioning of the battery system according to any of claims 1 to 5.
12. The system (1) of claim 10,
wherein the battery state monitored is the battery system state, and
wherein the system (1) further comprises the control unit (7) that is adopted to perform method (300) of monitoring a battery system state without interruption of functioning of the battery system (2) according to any of claims 6 to 9.
PCT/RU2018/000750 2018-11-15 2018-11-15 Method and system for monitoring a battery cell state and a battery system state without interruption of functioning of a battery system WO2020101521A1 (en)

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Citations (4)

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US6356058B1 (en) * 1998-10-01 2002-03-12 Honeywell International Inc. Method and apparatus for monitoring and maintaining a plurality of batteries
JP2006271068A (en) * 2005-03-23 2006-10-05 Nec Corp Battery device
WO2015132891A1 (en) * 2014-03-05 2015-09-11 株式会社日立製作所 Secondary battery module
US20160231385A1 (en) * 2015-02-10 2016-08-11 Lenovo Enterprise Solutions (Singapore) Pte. Ltd. Testing individual cells within multi-cell battery applications

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6356058B1 (en) * 1998-10-01 2002-03-12 Honeywell International Inc. Method and apparatus for monitoring and maintaining a plurality of batteries
JP2006271068A (en) * 2005-03-23 2006-10-05 Nec Corp Battery device
WO2015132891A1 (en) * 2014-03-05 2015-09-11 株式会社日立製作所 Secondary battery module
US20160231385A1 (en) * 2015-02-10 2016-08-11 Lenovo Enterprise Solutions (Singapore) Pte. Ltd. Testing individual cells within multi-cell battery applications

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