WO2019058666A1 - Secondary battery deterioration detection system - Google Patents

Secondary battery deterioration detection system Download PDF

Info

Publication number
WO2019058666A1
WO2019058666A1 PCT/JP2018/022916 JP2018022916W WO2019058666A1 WO 2019058666 A1 WO2019058666 A1 WO 2019058666A1 JP 2018022916 W JP2018022916 W JP 2018022916W WO 2019058666 A1 WO2019058666 A1 WO 2019058666A1
Authority
WO
WIPO (PCT)
Prior art keywords
secondary battery
battery
negative electrode
deterioration
potential
Prior art date
Application number
PCT/JP2018/022916
Other languages
French (fr)
Japanese (ja)
Inventor
友岳 竹内
Original Assignee
積水化学工業株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by 積水化学工業株式会社 filed Critical 積水化学工業株式会社
Priority to JP2019543414A priority Critical patent/JPWO2019058666A1/en
Publication of WO2019058666A1 publication Critical patent/WO2019058666A1/en

Links

Images

Classifications

    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H01M10/48—Accumulators combined with arrangements for measuring, testing or indicating the condition of cells, e.g. the level or density of the electrolyte
    • 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]
    • H—ELECTRICITY
    • H01—ELECTRIC ELEMENTS
    • H01M—PROCESSES OR MEANS, e.g. BATTERIES, FOR THE DIRECT CONVERSION OF CHEMICAL ENERGY INTO ELECTRICAL ENERGY
    • H01M10/00—Secondary cells; Manufacture thereof
    • H01M10/42—Methods or arrangements for servicing or maintenance of secondary cells or secondary half-cells
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02J—CIRCUIT ARRANGEMENTS OR SYSTEMS FOR SUPPLYING OR DISTRIBUTING ELECTRIC POWER; SYSTEMS FOR STORING ELECTRIC ENERGY
    • H02J7/00—Circuit arrangements for charging or depolarising batteries or for supplying loads from batteries
    • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
    • Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
    • Y02E60/10—Energy storage using batteries

Definitions

  • the present invention relates to, for example, a deterioration detection system of a secondary battery that constitutes a battery module.
  • Secondary batteries represented by lithium ion batteries are widely used not only for small electronic devices such as portable personal computers and mobile phones but also as power sources for vehicles such as hybrid vehicles (HVE) and electric vehicles (EV) in recent years ing.
  • HVE hybrid vehicles
  • EV electric vehicles
  • a secondary battery mounted on a vehicle is required to have high output and high capacity, in addition to increasing the volume of individual cells (cell batteries) constituting the secondary battery, a plurality of cell batteries A necessary output and capacity are obtained by connecting battery modules and connecting a plurality of battery modules to form a battery pack.
  • a lithium ion battery is gradually deteriorated through charge and discharge cycles, and the deterioration appears in the form of, for example, a decrease in battery capacity, charge and discharge efficiency, and maximum output current.
  • the cell battery (lithium ion battery) constituting the battery module is deteriorated, in order to maintain the predetermined performance of the battery module, the entire battery module is replaced or deteriorated depending on the detected failure. It is necessary to take measures such as exchanging the
  • a monitoring unit for monitoring the state of the cell battery or the battery module is provided, and it is performed to determine the presence or absence of abnormality of the cell battery or the battery module based on the monitoring result.
  • a method of determining the presence or absence of abnormality based on the result of measuring the internal temperature of the cell battery (temperature rise of the battery), voltage, current and the like is also performed to detect the presence or absence of abnormality by detecting a decrease in battery capacity and charge / discharge efficiency.
  • Patent Document 1 provides a reference electrode between the positive electrode and the negative electrode, and the impedance between the reference electrode and the positive electrode, the negative electrode measured based on the potential difference between the reference electrode and the positive electrode, the negative electrode A technique for simultaneously evaluating the electrode characteristics of the negative electrode is disclosed.
  • Patent Document 2 includes a positive electrode reference electrode connected to a positive electrode and a negative electrode reference electrode connected to a negative electrode, and the measured positive electrode potential and negative electrode potential, unit mass of positive electrode active material / negative electrode active material, positive electrode / negative electrode The deterioration state of the secondary battery is determined based on the charge / discharge characteristics of the positive electrode and the negative electrode per reference amount, using the unit area etc. of the
  • the cell battery is based on the deformation of the shape of the charge / discharge curve of the new battery and the deteriorated battery, the change of the internal impedance, the increase of the overvoltage, etc. (Deterioration of (lithium ion battery) is judged, and there is a problem that the device configuration for judgment of deterioration becomes complicated.
  • the present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a secondary battery deterioration detection system capable of quickly and easily diagnosing deterioration of a cell battery.
  • the present invention is a secondary battery deterioration detection system for detecting deterioration of a secondary battery performing charge and discharge by exchanging metal ions between a positive electrode and a negative electrode, and measuring the potential of the negative electrode based on a predetermined potential. And determining means for determining the presence or absence of deterioration of the secondary battery based on the potential of the negative electrode.
  • the secondary battery deterioration detection system is characterized in that, for example, the potential of the negative electrode indicates the remaining amount of the metal ion at the negative electrode after the discharge of the secondary battery.
  • the determination means is characterized by determining the presence or absence of the deterioration state of the secondary battery based on the potential of the negative electrode after the completion of the charge of the secondary battery. Furthermore, for example, the determination means predicts the occurrence of the deterioration of the secondary battery based on the change tendency of the potential of the negative electrode with respect to the passage of time.
  • one portion of the reference electrode is disposed inside the secondary battery, and the other portion is led to the outside of the secondary battery. Is located in a path along which the metal ions move between the positive electrode and the negative electrode.
  • the length of the exposed portion of the other portion of the secondary battery to the exterior of the secondary battery is shorter than the length of the portion of the negative electrode terminal of the secondary battery exposed to the exterior of the packaging.
  • the reference electrode is characterized in being disposed in a specific single secondary battery among a plurality of the secondary batteries.
  • the reference electrode is exposed to the outside of the exterior body from an arbitrary position of the sheet-like exterior body peripheral portion of the secondary battery.
  • the secondary battery is a lithium ion battery, and the metal ion is a lithium ion.
  • the deterioration of the cell battery (lithium ion battery) incorporated in the battery module can be determined promptly with a simple configuration.
  • FIG. 1 It is a block diagram showing composition of a rechargeable battery degradation detection system concerning an embodiment of the present invention. It is an outline view of a battery cell which constitutes a battery module in a rechargeable battery degradation detection system. It is a figure which shows typically the response
  • FIG. 1 is a block diagram showing a configuration of a secondary battery deterioration detection system according to an embodiment of the present invention.
  • FIG. 2 is an external view of the battery cell integrated in the battery module in the secondary battery deterioration detection system, Here, a part of exterior is fractured
  • the secondary battery deterioration detection system 1 shown in FIG. 1 constitutes a storage system for supplying power to an external load (not shown), and has a secondary battery deterioration detection function. Therefore, while managing and controlling the whole system of electric storage part 10 which consists of battery modules 21a-21d of plurality (here, four for convenience here) and secondary battery degradation detection system 1, a charge circuit and discharge which are not illustrated are shown. And a control unit 30 for controlling the circuit.
  • the control unit 30 functions as a battery management unit (BMU: Battery Management Unit) in the secondary battery deterioration detection system 1 and, for example, a central control unit (CPU) 31 composed of a microprocessor or the like, an operation program of the control unit 30, a control program Memory 33 storing detection data and the like for determining the presence or absence of deterioration of the secondary battery (also referred to as battery cell) as described later, and input of monitoring data from the battery modules 21b to 21d An interface unit 35 is provided.
  • BMU Battery Management Unit
  • the battery modules 21b to 21d include a plurality of battery cells (lithium ion batteries) 3a to 3s electrically connected in series, and cell monitoring units (CMU: Cell Monitoring Units) 25a to 25d described later.
  • CMU Cell Monitoring Units
  • a plurality of battery modules 21b to 21d connected to one another form a secondary battery module (also referred to as a battery pack), thereby maintaining a predetermined output voltage (secondary battery) System).
  • the battery cells 3a to 3s are sheet-stacked lithium ion secondary batteries (film type lithium ion single batteries) having a rectangular shape in plan view.
  • a plurality of film type lithium ion batteries as battery cells are vertically juxtaposed so that flat portions (portions indicated by a symbol P in FIG. 2) are in the left-right direction.
  • the flat portion (flat portion) P is stacked horizontally so as to be in the vertical direction.
  • the display unit 37 includes, for example, a liquid crystal display and the like, and as a monitoring result by the control unit 30, for example, a battery module in which battery cells are in a deteriorated state or a battery module in which the arrival of deterioration of battery cells is predicted It is displayed visually by the control number given to the battery module of
  • visible display As another example of visible display, arranging a plurality of lamps or the like corresponding to the arrangement of a plurality of battery modules in a two-dimensional planar shape makes it easy to grasp and check a battery module in which the battery cell is in a deteriorated state. .
  • means for emitting an alarm sound or the like corresponding to the deterioration of the battery cell may be provided.
  • a wireless transmission unit may be provided in the CMU, and a wireless reception unit may be provided in the control unit 30, and predetermined monitoring data may be exchanged by wireless communication using radio waves, infrared rays, and the like.
  • the battery cells 3a to 3s are film type lithium ion batteries as described above, and have a thickness of, for example, about 1 to 10 mm.
  • the battery cells 3a to 3s are made of, for example, an aluminum material, a polymer, and a laminate 53 in which a positive electrode plate (positive electrode sheet) 55 and a negative electrode plate (negative electrode sheet) 57, which are electrode plates, are laminated via an electrolyte layer and a separator (not shown). It seals by the sheet-like exterior body 47 which consists of films etc.
  • positive electrode terminal 41 is exposed to the outside of exterior body 47 as a tab for a terminal from positive electrode plate 55 on one end side in the longitudinal direction (longitudinal direction), and the other end in the longitudinal direction On the side, the negative electrode terminal 43 has a structure exposed from the negative electrode plate 57 to the outside of the exterior body 47 as a terminal tab.
  • the battery cells 3a to 3s further include a reference electrode 45 for measuring the potential of the negative electrode.
  • the reference electrode 45 is disposed such that a portion on one side thereof is located inside the battery cells 3a to 3s and a portion on the other side is exposed to the outside of the battery cells 3a to 3s.
  • the reference electrode 45 is made of, for example, copper, and part of the reference electrode 45 is covered with a resin coating (not shown) to maintain airtightness in the insertion portion into the laminate 53.
  • metal lithium is applied or embedded in the end portion 51 of the portion (the above one side portion) located inside the battery cells 3a to 3s and to be immersed in the electrolyte solvent. There is. Further, since the movement of lithium ions is linear, the portion of the reference electrode 45 which is immersed in the solvent of the electrolyte is between the positive electrode plate 55 and the negative electrode plate 57 and located in the path where the lithium ions move. You need to
  • the length L1 of the reference electrode terminal 45a of the reference electrode 45 exposed to the outside of the exterior body 47 is equal to the exposure length of the negative electrode terminal 43 or It is constructed shorter than.
  • part located in the laminated body 53 among the reference electrodes 45 will not be specifically limited if the length is a grade which the site
  • a signal line 49 for transmitting the potential measured by the reference electrode 45 as a signal is connected to the reference electrode terminal 45 a.
  • the external shape of the battery cell (lithium ion battery) according to the present embodiment is not limited to the film type described above, and may be, for example, a cylindrical shape, a square shape, a coin shape, or the like.
  • the battery cells 3a to 3s shown in FIG. 2 have a structure in which the positive electrode terminal 41 is exposed from one end side in the longitudinal direction and the negative electrode terminal 43 is exposed from the other end side. The structure may be exposed from the same end side of the battery cell.
  • the positive electrodes of the battery cells 3a to 3s have a positive electrode active material capable of reversibly introducing and releasing lithium ions.
  • positive electrode active materials include transition metal oxides such as lithium cobaltate (LiCoO 2 ), lithium nickelate (LiNiO 2 ), lithium manganate (LiMn 2 O 4 ), and olivine-type lithium iron phosphate (LiFePO 4 ).
  • the negative electrode also has a negative electrode active material capable of reversibly introducing and releasing lithium ions. Examples of the negative electrode active material include metal lithium, a lithium alloy, a carbon-based material capable of inserting and extracting lithium, and a metal oxide.
  • the separator has an insulating property, and has a function of preventing a short circuit between the positive electrode and the negative electrode and a function of holding an electrolytic solution.
  • the separator is not particularly limited as long as it can hold or pass the electrolytic solution, but, for example, a microporous polymer film (for example, a thin film resin film such as PP (polypropylene) or PE (polyethylene)), non-woven fabric, It consists of glass fiber etc.
  • non-aqueous solvent substantially free of water for example, less than 100 ppm
  • non-aqueous solvents include propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, dimethoxyethane, ⁇ -butyrolactone, methyl acetate, methyl formate, toluene, hexane and the like, and one of them is The species can be used alone or in combination of two or more.
  • the electrolyte for example, lithium hexafluorophosphate, lithium perchlorate, lithium salts such as lithium tetrafluoroborate, and the like can be suitably used.
  • the concentration of the electrolyte in the electrolytic solution is not particularly limited, but is preferably about 0.01 to 1 M.
  • FIG. 3 schematically shows the correspondence between the passage of time (charge-discharge cycle) and the change in electrode potential in a lithium ion battery.
  • FIG. 4 is a flowchart which shows the degradation determination procedure of the lithium ion battery in the secondary battery degradation detection system which concerns on this embodiment.
  • the vertical axis in FIG. 3 represents the potential (unit: V) of an electrode or the like of a lithium ion battery, and here, the potential after charging is shown.
  • the horizontal axis is elapsed time (cycle number).
  • the cycle number is the number of repetitions of charging and discharging of the cell battery (lithium ion battery).
  • the plurality of battery cells (lithium ion batteries) 3a to 3s constituting the battery modules 21a to 21d use the above-described organic solvent as an electrolytic solution, and the positive electrode and the negative electrode Charge and discharge are performed by the movement of lithium ions between them. Therefore, the deterioration of the electrode due to the oxidation-reduction reaction in the battery using an acid or alkaline aqueous solution as the electrolytic solution and the decrease of the ion conductivity due to the electrolysis of the electrolytic solution do not occur.
  • lithium ions reach the electrode, metal lithium is deposited, and the number of lithium ions decreases, whereby the charge capacity and the discharge capacity of the battery decrease due to the repetition of charge and discharge cycles.
  • polarization may occur inside the battery and lithium ions may be polarized at the negative electrode. Such polarization stops charging and discharging, and is not eliminated even if time passes.
  • the secondary battery deterioration detection system focuses on lithium ions (Li + ) remaining on the negative electrode even after discharge due to the progress of charge and discharge cycles, etc.
  • the amount of decrease in the negative electrode potential is detected to judge and evaluate the deterioration of the lithium ion battery.
  • the reference electrode 45 for measuring the potential of the negative electrode is disposed in the battery cells 3a to 3s of the secondary battery deterioration detection system 1, and the degree of polarization due to lithium ion remaining on the negative electrode is detected based on the negative electrode potential. Then, the presence or absence of deterioration of the lithium ion battery is determined based on the detection result.
  • the arrangement of the reference electrodes in the battery cell of the secondary battery deterioration detection system according to the present embodiment will be described. If a failure occurs in part of a plurality of battery cells constituting the battery module, the function as the battery module, that is, the storage system (secondary battery system) mounted with the battery module can not exhibit its inherent performance. In addition, when there is a variation in battery characteristics among a plurality of cell batteries connected in series constituting the battery module, the cell battery with the lowest battery characteristic becomes dominant, and the storage battery (the secondary battery system) ) It is considered that the overall characteristics, reliability, etc. are limited.
  • the center of the plurality of lithium ion batteries assumed to have severe conditions such as use environment and installation environment
  • the reference electrode 45 is disposed only in one cell battery located in a part.
  • one cell battery (cell battery 3 j in the battery module 21 a shown in FIG. 1 and cell battery 21 b in the battery module 21 b shown in FIG. 1) located at the center of a plurality of lithium ion batteries arranged in parallel or stacked continuously.
  • a reference electrode is disposed on the cell 4 j, the cell module 5 c in the cell module 21 c, and the cell cell 6 j) in the cell module 21 d.
  • Signal lines 49a to 49d are connected between the reference electrode of each cell battery and the cell monitoring unit (CMU).
  • the lithium ion battery maintains the positive electrode potential and the negative electrode potential at a constant value in the stage of the initial product after production indicated by symbol A in FIG.
  • a cell voltage Vc of the potential difference is lithium ion battery positive electrode potential and negative electrode potential, here, the negative electrode potential of a lithium ion battery in the initial product stage as measured by the reference electrode is V 0.
  • Potentials V 1 to V n in FIG. 3 indicate a change (potential decrease) of the negative electrode potential measured at the reference electrode, with 0 V on the vertical axis as a reference potential.
  • the central control unit (CPU) 31 functioning as a battery management device (BMU) is configured to use a cell battery (based on the negative electrode potential measured by the reference electrode 45). Judge the occurrence of deterioration in the lithium ion battery).
  • the central control unit (CPU) 31 first performs initial setting for deterioration determination in step S11 of FIG. 4 as detection of battery cell deterioration (degradation diagnosis) in the secondary battery deterioration detection system 1. That is, the negative electrode potential V 0 (hereinafter also referred to as an initial potential) and the like of the lithium ion battery in the initial charged state (the cell battery of the initial product) is stored in the memory 33 as initial data.
  • Anode potential V 0 In this case, the charge-discharge cycle of the state before the start or after the charge-discharge cycle start, but have passed considerable time, the negative electrode potential in a state of lithium ion in the negative electrode does not remain, is there.
  • step S 13 the central control unit (CPU) 31 receives the negative electrode potential V ⁇ measured by the reference electrode as monitoring data via the cell monitoring units (CMU) 25 a to 25 d and the interface unit 35.
  • step S15 the initial potential V 0 lithium ion battery in the initial product stage, negative electrode potential V received - calculating the - difference between (V 0 -V).
  • step S17 the potential difference component (V 0 -V -) to determine whether it exceeds a predetermined threshold value Vth. For example, if it is the first measurement timing, whether the difference (V 0 -V 1 ) between the initial potential V 0 and the negative electrode potential V 1 shown in FIG. 3 measured at the reference electrode exceeds the threshold value Vth Determine If the difference (V 0 -V 1 ) does not exceed the threshold value Vth, the central control unit (CPU) 31 determines that deterioration due to lithium ions remaining in the negative electrode of the cell battery has not occurred (normal) ( Step S23).
  • the threshold value Vth is, for example, 50% to 80% of the initial capacity after the cycle test in advance for a plurality of lithium ion batteries of the same specification as the cell battery (lithium ion battery) incorporated in the battery module.
  • the negative electrode potential may be measured and determined based on the result.
  • the central control unit (CPU) 31 determines whether the cell battery is in a mode requiring charging based on the total discharge time of the cell battery, the cell voltage and the like. If the cell battery needs charging, charging is performed in step S27, and it is determined in step S29 that the charging is completed if, for example, the output voltage of the cell battery has reached the upper limit voltage.
  • the central control unit (CPU) 31 measures the reference electrode at the next measurement timing (the second time) via the cell monitoring units (CMU) 25a to 25d and the interface unit 35 in step S13.
  • negative electrode potential V - the received as monitoring data.
  • step S15 the difference (V 0 -V 2 ) between the initial potential V 0 and the negative electrode potential V 2 at the second measurement timing is determined, and in the subsequent step S17, the difference (V 0 -V 2 ) is It is determined whether the threshold value Vth is exceeded.
  • the central control unit (CPU) 31 sequentially receives the negative electrode potential V ⁇ measured at the reference electrode at predetermined measurement timing as monitoring data in step S13, and the initial potential V 0 in step S17. Then, the difference (V 0 -V 3 ),... (V 0 -V n ) with the negative electrode potential at the measurement timing is determined.
  • the lithium ion battery (cell battery) tends to drop in voltage during discharge, in the secondary battery deterioration detection system according to the present embodiment, as described above, the initial potential V 0 after charging the cell battery. The difference with the negative electrode potential V ⁇ measured at the reference electrode is obtained.
  • step S17 determines in step S17 that the above-described potential difference exceeds the threshold value Vth, the number of charge and discharge cycles has progressed in step S19 and the lithium number is increased to the negative electrode. It is judged that the ions remain (lithium ions are polarized) and the cell battery to be monitored is deteriorated.
  • step S21 as a monitoring result, for example, the administrator or maintenance personnel of the secondary battery deterioration detection system can specify the battery module whose battery cell is in a deteriorated state as a monitoring result in the display unit 37 composed of a liquid crystal display or the like. Make it visible.
  • the administrator etc. of the secondary battery deterioration detection system needs to take measures to maintain the function of the secondary battery deterioration detection system, such as replacement of a battery module (assembled battery) including a deteriorated battery cell. It can be recognized that there is.
  • the reference electrode is disposed in the cell battery (lithium ion battery), the potential of the negative electrode is measured, and the deterioration of the lithium ion battery is determined based on the measured negative electrode potential. That is, by detecting the amount (degree of polarization) of lithium ions remaining in the negative electrode even after discharge based on the potential of the negative electrode, the cell battery can be rapidly degraded with a simple configuration without providing a dedicated sensor. Can judge.
  • lithium ions are left on the negative electrode due to cycle life due to repeated charge and discharge, etc., and battery cells degraded in battery performance can be detected promptly and degraded It is possible to replace the mounted battery module in a short time and ensure the normal operation of the storage system.
  • the reference electrode only on a specific single cell battery among the plurality of cell batteries constituting the battery module and detecting the deterioration of the cell battery, all the negative electrode potentials of the plurality of cell batteries This makes it possible to avoid the complication of the degradation detection configuration as compared with a system configuration in which the presence or absence of degradation is monitored by measuring one by one.
  • the presence or absence of the deterioration of the battery cell is determined based on the result of comparing the difference between the initial potential V 0 and the negative electrode potential sequentially determined at a predetermined timing with the threshold value Vth. It is good also as composition of predicting degradation of a battery cell as follows.
  • FIG. 5 is a diagram for describing a method of determining deterioration (deterioration prediction) of the battery cell according to the first modification.
  • the negative electrode potential V ⁇ after completion of charging is measured a predetermined number of times, and these are plotted on a graph (potentials V 1 , V 2 , V 3 indicated by black circles in FIG. 5) . Then, based on the decrease in the potential formed by connecting these points, the negative electrode potential V - catching expected line for predicting the change in (indicated by the broken line in FIG. 5).
  • Central control unit (CPU) 31 based on the predicted line, the initial potential V 0 cell, the negative electrode potential V in the prediction line - the difference ⁇ V between exceeds a threshold Vth the predicted time (cell battery It is a time when the occurrence of deterioration is predicted, and the time indicated by a symbol B in FIG.
  • the prediction line is drawn based on the decreasing tendency of the negative electrode potential V ⁇ , and the occurrence time of the deterioration of the cell battery is determined based on it, so that the battery module is replaced in advance before the actual deterioration occurs. We can know the arrival of time. Further, the battery module can be replaced at a stage prior to the occurrence of a defect in the battery module due to the deteriorated battery cell, and it is possible to prevent an abrupt stop of operation or the like of a device receiving power supply from the battery module.
  • the reference electrode terminal 45a is exposed from the same side as the side where the negative electrode terminal 43 protrudes, but the form of exposure is limited thereto. I will not.
  • the reference electrode terminal can be disposed at any position of the battery cell. For example, as in the reference electrode terminals 45a to 45d shown in FIG. 6A, a sheet-like package of battery cells 3a to 3s having a rectangular planar shape It is good also as composition exposed from arbitrary positions of four peripheral parts.
  • the reference electrode terminals 65a to 65d may be exposed at arbitrary positions of the four peripheral portions of the sheet-like outer package.
  • the deterioration of the lithium ion battery is judged and evaluated based on the decrease of the negative electrode potential due to the remaining of the inactivated lithium ion by the reference electrode, but the present invention is not limited thereto.
  • the decrease in positive electrode potential caused by the decrease in lithium ion storage amount in the positive electrode plate may be detected by the reference electrode, and the deterioration of the lithium ion battery may be determined based on the result.

Abstract

[Problem] To provide a secondary battery deterioration detection system which can easily detect deterioration in cells (lithium-ion batteries) constituting a battery module. [Solution] In a secondary battery deterioration detection system 1, a reference electrode 45 is provided to one cell among a plurality of cells (lithium-ion batteries) 3a-3s included in each of battery modules 21b-21d, to measure the potential of the negative electrode of that cell. The presence or absence of a deterioration in the lithium-ion battery is determined on the basis of the negative electrode potential indicating the amount of lithium ions (the level of polarization) remaining in the negative electrode even after discharge.

Description

二次電池劣化検出システムSecondary battery deterioration detection system
　本発明は、例えば電池モジュールを構成する二次電池の劣化検出システムに関する。 The present invention relates to, for example, a deterioration detection system of a secondary battery that constitutes a battery module.
　リチウムイオン電池に代表される二次電池は、携帯用パソコン、携帯電話機等の小型電子機器のみならず、近年では、ハイブリッド自動車（ＨＶＥ）、電気自動車（ＥＶ）等の車両の動力電源として多用されている。特に車両に搭載されるニ次電池は、高出力と高容量が求められるため、その二次電池を構成する個々の単電池（セル電池）の大容積化に加えて、複数個のセル電池を連結して電池モジュールを構成し、さらに電池モジュールを複数個接続して組電池とすることで、必要な出力と容量を得ている。 Secondary batteries represented by lithium ion batteries are widely used not only for small electronic devices such as portable personal computers and mobile phones but also as power sources for vehicles such as hybrid vehicles (HVE) and electric vehicles (EV) in recent years ing. In particular, since a secondary battery mounted on a vehicle is required to have high output and high capacity, in addition to increasing the volume of individual cells (cell batteries) constituting the secondary battery, a plurality of cell batteries A necessary output and capacity are obtained by connecting battery modules and connecting a plurality of battery modules to form a battery pack.
　リチウムイオン電池は、充放電サイクルを経ることで徐々に劣化し、その劣化は、例えば電池容量、充放電効率、最大出入力電流の低下という形で現れることが知られている。電池モジュールを構成するセル電池（リチウムイオン電池）に劣化が生じた場合、電池モジュールが所定の性能を維持するには、検知された不具合に応じて、電池モジュール全体の交換、あるいは劣化したセル電池を個別に交換する等の対応が必要となる。 It is known that a lithium ion battery is gradually deteriorated through charge and discharge cycles, and the deterioration appears in the form of, for example, a decrease in battery capacity, charge and discharge efficiency, and maximum output current. When the cell battery (lithium ion battery) constituting the battery module is deteriorated, in order to maintain the predetermined performance of the battery module, the entire battery module is replaced or deteriorated depending on the detected failure. It is necessary to take measures such as exchanging the
　そこで従来より、セル電池や電池モジュールの状態を監視する監視ユニットを設け、その監視結果をもとにセル電池、電池モジュールの異常の有無を判断することが行われている。具体的には、セル電池の内部温度（電池の温度上昇）、電圧、電流等を測定した結果をもとに異常の有無を判定する方法が知られている。また、電池容量と充放電効率の低下を検知して、異常の有無を判定することも行われている。 Therefore, conventionally, a monitoring unit for monitoring the state of the cell battery or the battery module is provided, and it is performed to determine the presence or absence of abnormality of the cell battery or the battery module based on the monitoring result. Specifically, there is known a method of determining the presence or absence of abnormality based on the result of measuring the internal temperature of the cell battery (temperature rise of the battery), voltage, current and the like. In addition, it is also performed to detect the presence or absence of abnormality by detecting a decrease in battery capacity and charge / discharge efficiency.
　例えば、特許文献１は、正極と負極の間に参照極を設け、その参照極と正極、負極の電位差等をもとに測定した参照極と正極、負極間のインピーダンスより、電池の正極およ負極の電極特性を同時に評価する技術を開示している。また、特許文献２では、正極と接続された正極参照電極と、負極と接続された負極参照電極を備え、計測した正極電位と負極電位、正極活物質・負極活物質の単位質量、正極・負極の単位面積等を基準量として、その基準量あたりの正極および負極の充放電特性に基づいて二次電池の劣化状態を判定している。 For example, Patent Document 1 provides a reference electrode between the positive electrode and the negative electrode, and the impedance between the reference electrode and the positive electrode, the negative electrode measured based on the potential difference between the reference electrode and the positive electrode, the negative electrode A technique for simultaneously evaluating the electrode characteristics of the negative electrode is disclosed. Further, Patent Document 2 includes a positive electrode reference electrode connected to a positive electrode and a negative electrode reference electrode connected to a negative electrode, and the measured positive electrode potential and negative electrode potential, unit mass of positive electrode active material / negative electrode active material, positive electrode / negative electrode The deterioration state of the secondary battery is determined based on the charge / discharge characteristics of the positive electrode and the negative electrode per reference amount, using the unit area etc. of the
特開２０１６－４８２１３号公報JP, 2016-48213, A 特表２０１５－４５０１５号公報JP-A-2015-45015
　リチウムイオン電池の劣化を判定する場合、充放電サイクルにおけるリチウムイオン電池の電池容量、充放電効率の低下等を測定したり、電池内部での劣化部位の特定、および劣化要因を解明することが重要となるが、このような測定等を行うことは劣化の判断に時間とコストを要するため、劣化判断の迅速性、費用対効果の観点から採用できない。 When determining the deterioration of a lithium ion battery, it is important to measure the battery capacity of the lithium ion battery in the charge and discharge cycle, the decrease in charge and discharge efficiency, etc., to identify the deterioration site inside the battery, and to clarify the deterioration factor. However, performing such measurements requires time and cost to judge the deterioration, so it can not be adopted from the viewpoint of the promptness of the deterioration judgment and the cost-effectiveness.
　また、上述した特許文献１，２に記載の劣化判定方法は、新品の電池と劣化した電池との充放電曲線の形状の変形、内部インピーダンスの変化、あるいは過電圧の増加等をもとにセル電池（リチウムイオン電池）の劣化を判断しており、劣化判断のための装置構成が複雑になるという問題がある。 Further, in the deterioration determination method described in Patent Documents 1 and 2 described above, the cell battery is based on the deformation of the shape of the charge / discharge curve of the new battery and the deteriorated battery, the change of the internal impedance, the increase of the overvoltage, etc. (Deterioration of (lithium ion battery) is judged, and there is a problem that the device configuration for judgment of deterioration becomes complicated.
　本発明は、上述した課題に鑑みてなされたものであり、その目的とするところは、セル電池の劣化診断を迅速かつ簡便に行うことができる二次電池劣化検出システムを提供することである。 The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a secondary battery deterioration detection system capable of quickly and easily diagnosing deterioration of a cell battery.
　上記の目的を達成し、上述した課題を解決する一手段として以下の構成を備える。すなわち本発明は、正極と負極間で金属イオンをやり取りすることで充放電を行う二次電池の劣化を検出する二次電池劣化検出システムであって、所定電位を基準として前記負極の電位を測定する参照電極と、前記負極の電位に基づいて前記二次電池の劣化の有無を判定する判定手段とを備えることを特徴とする。 The following configuration is provided as means for achieving the above object and solving the problems described above. That is, the present invention is a secondary battery deterioration detection system for detecting deterioration of a secondary battery performing charge and discharge by exchanging metal ions between a positive electrode and a negative electrode, and measuring the potential of the negative electrode based on a predetermined potential. And determining means for determining the presence or absence of deterioration of the secondary battery based on the potential of the negative electrode.
　本発明の二次電池劣化検出システムでは、例えば前記負極の電位が、前記二次電池の放電後における該負極での前記金属イオンの残存量を示していることを特徴とする。また、例えば前記判定手段は、前記二次電池の充電完了後における前記負極の電位をもとに該二次電池の劣化状態の有無を判定することを特徴とする。さらに、例えば前記判定手段は、時間経過に対する前記負極の電位の変化傾向に基づいて前記二次電池の劣化の発生を予測することを特徴とする。 The secondary battery deterioration detection system according to the present invention is characterized in that, for example, the potential of the negative electrode indicates the remaining amount of the metal ion at the negative electrode after the discharge of the secondary battery. Further, for example, the determination means is characterized by determining the presence or absence of the deterioration state of the secondary battery based on the potential of the negative electrode after the completion of the charge of the secondary battery. Furthermore, for example, the determination means predicts the occurrence of the deterioration of the secondary battery based on the change tendency of the potential of the negative electrode with respect to the passage of time.
　また、本発明の二次電池劣化検出システムでは、例えば、前記参照電極の一方部位が前記二次電池の内部に配置され、他方部位が該二次電池の外部に導出されており、前記一方部位は前記正極と前記負極間において前記金属イオンが移動する経路内に位置することを特徴とする。例えば、前記他方部位のうち前記二次電池の外装体外部への露出部分の長さは、前記二次電池の負極端子のうち該外装体外部に露出している部分の長さよりも短いことを特徴とする。また、例えば、前記参照電極は、複数の前記二次電池のうち特定の単一の二次電池に配置されていることを特徴とする。さらに、例えば前記参照電極は、前記二次電池のシート状外装体周縁部の任意の位置より該外装体の外部へ露出していることを特徴とする。さらには、例えば前記二次電池はリチウムイオン電池であり、前記金属イオンはリチウムイオンであることを特徴とする。 Moreover, in the secondary battery deterioration detection system of the present invention, for example, one portion of the reference electrode is disposed inside the secondary battery, and the other portion is led to the outside of the secondary battery. Is located in a path along which the metal ions move between the positive electrode and the negative electrode. For example, the length of the exposed portion of the other portion of the secondary battery to the exterior of the secondary battery is shorter than the length of the portion of the negative electrode terminal of the secondary battery exposed to the exterior of the packaging. It features. Further, for example, the reference electrode is characterized in being disposed in a specific single secondary battery among a plurality of the secondary batteries. Furthermore, for example, the reference electrode is exposed to the outside of the exterior body from an arbitrary position of the sheet-like exterior body peripheral portion of the secondary battery. Furthermore, for example, the secondary battery is a lithium ion battery, and the metal ion is a lithium ion.
　本発明によれば、電池モジュールに組み込まれたセル電池（リチウムイオン電池）の劣化を簡易な構成で迅速に判断できる。 According to the present invention, the deterioration of the cell battery (lithium ion battery) incorporated in the battery module can be determined promptly with a simple configuration.
本発明の実施形態に係る二次電池劣化検出システムの構成を示すブロック図である。It is a block diagram showing composition of a rechargeable battery degradation detection system concerning an embodiment of the present invention. 二次電池劣化検出システムにおいて電池モジュールを構成する電池セルの外観図である。It is an outline view of a battery cell which constitutes a battery module in a rechargeable battery degradation detection system. リチウムイオン電池における時間経過（充放電サイクル）と電極電位の変化との対応を模式的に示す図である。It is a figure which shows typically the response | compatibility with the time progress (charge-and-discharge cycle) in the lithium ion battery, and the change of an electrode electric potential. 本実施形態に係る二次電池劣化検出システムにおけるリチウムイオン電池の劣化判定手順を示すフローチャートである。It is a flowchart which shows the degradation determination procedure of the lithium ion battery in the secondary battery degradation detection system which concerns on this embodiment. 変形例１に係る電池セルの劣化判断（劣化予測）方法を説明する図である。It is a figure explaining the degradation judgment (deterioration prediction) method of the battery cell concerning modification 1. FIG. 電池セルにおける参照電極端子の配置位置の例を示す図である。It is a figure which shows the example of the arrangement position of the reference electrode terminal in a battery cell.
　以下、本発明の実施形態について添付図面を参照して詳細に説明する。図１は、本発明の実施形態に係る二次電池劣化検出システムの構成を示すブロック図である。また、図２は、二次電池劣化検出システムにおいて電池モジュールに組み込まれた電池セルの外観図であり、ここでは、外装の一部を破断してセル電池の内部構造を示している。 Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings. FIG. 1 is a block diagram showing a configuration of a secondary battery deterioration detection system according to an embodiment of the present invention. Moreover, FIG. 2 is an external view of the battery cell integrated in the battery module in the secondary battery deterioration detection system, Here, a part of exterior is fractured | ruptured and the internal structure of a cell battery is shown.
　図１に示す二次電池劣化検出システム１は、不図示の外部負荷に電力を供給する蓄電システムを構成しており、二次電池の劣化検出機能を備えている。そのため、複数（ここでは便宜上、４個とする）の電池モジュール２１ａ～２１ｄからなる蓄電部１０と、二次電池劣化検出システム１のシステム全体を管理、制御するとともに、不図示の充電回路および放電回路を制御する制御部３０とを備える。 The secondary battery deterioration detection system 1 shown in FIG. 1 constitutes a storage system for supplying power to an external load (not shown), and has a secondary battery deterioration detection function. Therefore, while managing and controlling the whole system of electric storage part 10 which consists of battery modules 21a-21d of plurality (here, four for convenience here) and secondary battery degradation detection system 1, a charge circuit and discharge which are not illustrated are shown. And a control unit 30 for controlling the circuit.
　制御部３０は、二次電池劣化検出システム１におけるバッテリ管理装置（ＢＭＵ：Battery Management Unit）として機能し、例えばマイクロプロセッサ等からなる中央制御部（ＣＰＵ）３１、制御部３０の動作プログラム、制御プログラムが格納されるとともに、後述するように二次電池（電池セルともいう）の劣化の有無を判断するための検知データ等が蓄積されるメモリ３３、電池モジュール２１ｂ～２１ｄからの監視データ等の入力部であるインタフェース部３５を備える。 The control unit 30 functions as a battery management unit (BMU: Battery Management Unit) in the secondary battery deterioration detection system 1 and, for example, a central control unit (CPU) 31 composed of a microprocessor or the like, an operation program of the control unit 30, a control program Memory 33 storing detection data and the like for determining the presence or absence of deterioration of the secondary battery (also referred to as battery cell) as described later, and input of monitoring data from the battery modules 21b to 21d An interface unit 35 is provided.
　電池モジュール２１ｂ～２１ｄは、電気的に直列接続された複数の電池セル（リチウムイオン電池）３ａ～３ｓと、後述するセル監視ユニット（ＣＭＵ：Cell Monitoring Unit）２５ａ～２５ｄを有する。二次電池劣化検出システム１は、相互に連結された複数個の電池モジュール２１ｂ～２１ｄが二次電池モジュール（組電池ともいう）となり、それにより所定の出力電圧を維持する蓄電システム（二次電池システム）が構成される。 The battery modules 21b to 21d include a plurality of battery cells (lithium ion batteries) 3a to 3s electrically connected in series, and cell monitoring units (CMU: Cell Monitoring Units) 25a to 25d described later. In the secondary battery deterioration detection system 1, a plurality of battery modules 21b to 21d connected to one another form a secondary battery module (also referred to as a battery pack), thereby maintaining a predetermined output voltage (secondary battery) System).
　電池セル３ａ～３ｓは、平面視したときの形状が長方形のシート積層型リチウムイオン二次電池（フィルム型リチウムイオン単電池）である。図１に示す電池モジュール２１ｂ～２１ｄ内では、電池セルとしてのフィルム型リチウムイオン電池が、その平面部分（図２において、符号Ｐで示す部分）が左右方向となるように縦置きに複数個並置され、あるいは平面部分（平坦部）Ｐが上下方向となるように横置きに積層されている。 The battery cells 3a to 3s are sheet-stacked lithium ion secondary batteries (film type lithium ion single batteries) having a rectangular shape in plan view. In the battery modules 21b to 21d shown in FIG. 1, a plurality of film type lithium ion batteries as battery cells are vertically juxtaposed so that flat portions (portions indicated by a symbol P in FIG. 2) are in the left-right direction. Or the flat portion (flat portion) P is stacked horizontally so as to be in the vertical direction.
　表示部３７は、例えば液晶表示器等からなり、制御部３０による監視結果として、例えば、電池セルが劣化状態にある電池モジュール、あるいは電池セルの劣化の到来が予測される電池モジュールを、あらかじめそれらの電池モジュールに付与した管理番号等により可視表示する。 The display unit 37 includes, for example, a liquid crystal display and the like, and as a monitoring result by the control unit 30, for example, a battery module in which battery cells are in a deteriorated state or a battery module in which the arrival of deterioration of battery cells is predicted It is displayed visually by the control number given to the battery module of
　可視表示の他の例として、複数の電池モジュールの配列に対応させた複数のランプ等を２次元平面状に配置することで、電池セルが劣化状態にある電池モジュールの把握、確認が容易になる。なお、これらの可視表示とともに、電池セルの劣化に対応した警報音等を発する手段を設けてもよい。 As another example of visible display, arranging a plurality of lamps or the like corresponding to the arrangement of a plurality of battery modules in a two-dimensional planar shape makes it easy to grasp and check a battery module in which the battery cell is in a deteriorated state. . In addition to these visible displays, means for emitting an alarm sound or the like corresponding to the deterioration of the battery cell may be provided.
　セル監視ユニット（ＣＭＵ）２５ａ～２５ｄを備える蓄電部１０と、ＣＭＵからの監視データを受信する制御部３０との間は、有線による通信形態に限定されない。例えば、ＣＭＵに無線送信部を設け、制御部３０に無線受信部を設けて、電波、赤外線等による無線通信で所定の監視データをやり取りしてもよい。 There is no limitation on wired communication between the storage unit 10 including the cell monitoring units (CMU) 25a to 25d and the control unit 30 that receives monitoring data from the CMU. For example, a wireless transmission unit may be provided in the CMU, and a wireless reception unit may be provided in the control unit 30, and predetermined monitoring data may be exchanged by wireless communication using radio waves, infrared rays, and the like.
　電池セル３ａ～３ｓは、上述したようにフィルム型のリチウムイオン電池であり、厚さが例えば１～１０ｍｍ程度である。電池セル３ａ～３ｓは、電極板である正極板（正極シート）５５と負極板（負極シート）５７を不図示の電解質層およびセパレータを介して積層した積層体５３を、例えば、アルミニウム材料、ポリマーフィルム等からなるシート状の外装体４７で封止してなる。 The battery cells 3a to 3s are film type lithium ion batteries as described above, and have a thickness of, for example, about 1 to 10 mm. The battery cells 3a to 3s are made of, for example, an aluminum material, a polymer, and a laminate 53 in which a positive electrode plate (positive electrode sheet) 55 and a negative electrode plate (negative electrode sheet) 57, which are electrode plates, are laminated via an electrolyte layer and a separator (not shown). It seals by the sheet-like exterior body 47 which consists of films etc.
　また、電池セル３ａ～３ｓは、その長尺方向（長手方向）の一方端側に、正極板５５より端子用タブとして正極端子４１が外装体４７の外部に露出し、長尺方向の他方端側には、負極板５７より端子用タブとして負極端子４３が外装体４７の外部に露出した構造を有する。さらに電池セル３ａ～３ｓは、負極の電位を測定するための参照電極４５を有する。参照電極４５は、その一方側の部位が電池セル３ａ～３ｓの内部に位置し、他方側の部位が電池セル３ａ～３ｓの外部に露出するように配置されている。 In battery cells 3a to 3s, positive electrode terminal 41 is exposed to the outside of exterior body 47 as a tab for a terminal from positive electrode plate 55 on one end side in the longitudinal direction (longitudinal direction), and the other end in the longitudinal direction On the side, the negative electrode terminal 43 has a structure exposed from the negative electrode plate 57 to the outside of the exterior body 47 as a terminal tab. The battery cells 3a to 3s further include a reference electrode 45 for measuring the potential of the negative electrode. The reference electrode 45 is disposed such that a portion on one side thereof is located inside the battery cells 3a to 3s and a portion on the other side is exposed to the outside of the battery cells 3a to 3s.
　参照電極４５は、例えば銅からなり、その一部を樹脂製の被覆（不図示）で覆うことで積層体５３への挿入部分における気密性を保持する。参照電極４５のうち、電池セル３ａ～３ｓの内部に位置する部位（上記の一方側の部位）であって、電解液溶媒に浸る部位の先端部５１には、金属リチウムが塗布あるいは埋め込まれている。また、リチウムイオンの移動には直線性があるため、参照電極４５のうち電解液溶媒に浸る部位は、正極板５５と負極板５７との間であって、リチウムイオンが移動する経路内に位置している必要がある。 The reference electrode 45 is made of, for example, copper, and part of the reference electrode 45 is covered with a resin coating (not shown) to maintain airtightness in the insertion portion into the laminate 53. Of the reference electrode 45, metal lithium is applied or embedded in the end portion 51 of the portion (the above one side portion) located inside the battery cells 3a to 3s and to be immersed in the electrolyte solvent. There is. Further, since the movement of lithium ions is linear, the portion of the reference electrode 45 which is immersed in the solvent of the electrolyte is between the positive electrode plate 55 and the negative electrode plate 57 and located in the path where the lithium ions move. You need to
　参照電極４５のうち外装体４７の外部に露出している参照電極端子４５ａの長さ（外装体４７の端部４４から延伸する長さ）Ｌ１は、負極端子４３の露出長と同等、あるいはそれよりも短く構成されている。また、参照電極４５のうち、積層体５３内に位置する部位の長さＬ２は、その部位が電解液溶媒に確実に浸る程度の長さであれば、特に限定されない。なお、参照電極端子４５ａには、参照電極４５で測定された電位を信号として伝送するための信号線４９が接続されている。 The length L1 of the reference electrode terminal 45a of the reference electrode 45 exposed to the outside of the exterior body 47 (length extending from the end 44 of the exterior body 47) is equal to the exposure length of the negative electrode terminal 43 or It is constructed shorter than. Moreover, length L2 of the site | part located in the laminated body 53 among the reference electrodes 45 will not be specifically limited if the length is a grade which the site | part will certainly be immersed in electrolyte solution solvent. A signal line 49 for transmitting the potential measured by the reference electrode 45 as a signal is connected to the reference electrode terminal 45 a.
　本実施形態に係る電池セル（リチウムイオン電池）の外観形状は、上述したフィルム型に限定されず、例えば円筒型、角型、コイン型等であってもよい。また、図２に示す電池セル３ａ～３ｓは、長手方向の一方端側から正極端子４１が露出し、他方端側から負極端子４３が露出する構造となっているが、正極端子と負極端子を電池セルの同一端側から露出させた構造としてもよい。 The external shape of the battery cell (lithium ion battery) according to the present embodiment is not limited to the film type described above, and may be, for example, a cylindrical shape, a square shape, a coin shape, or the like. The battery cells 3a to 3s shown in FIG. 2 have a structure in which the positive electrode terminal 41 is exposed from one end side in the longitudinal direction and the negative electrode terminal 43 is exposed from the other end side. The structure may be exposed from the same end side of the battery cell.
　電池セル３ａ～３ｓの正極は、リチウムイオンを可逆的に導入および放出可能な正極活物質を有する。正極活物質として、例えばコバルト酸リチウム（ＬｉＣｏＯ２）、ニッケル酸リチウム（ＬｉＮｉＯ２）、マンガン酸リチウム（ＬｉＭｎ２Ｏ４）、オリビン型リン酸鉄リチウム（ＬｉＦｅＰＯ４）等の遷移金属酸化物がある。また、負極も、リチウムイオンを可逆的に導入および放出可能な負極活物質を有する。負極活物質として、例えば金属リチウム、リチウム合金、リチウムを吸蔵、放出し得る炭素系材料、金属酸化物等を挙げることができる。 The positive electrodes of the battery cells 3a to 3s have a positive electrode active material capable of reversibly introducing and releasing lithium ions. Examples of positive electrode active materials include transition metal oxides such as lithium cobaltate (LiCoO 2 ), lithium nickelate (LiNiO 2 ), lithium manganate (LiMn 2 O 4 ), and olivine-type lithium iron phosphate (LiFePO 4 ). . The negative electrode also has a negative electrode active material capable of reversibly introducing and releasing lithium ions. Examples of the negative electrode active material include metal lithium, a lithium alloy, a carbon-based material capable of inserting and extracting lithium, and a metal oxide.
　セパレータは、絶縁性を有し、正極と負極との短絡を防止する機能および電解液を保持する機能を有する。セパレータは、電解液を保持または通過させることが可能であれば特に限定されないが、例えば高分子の微多孔性膜（例えば、ＰＰ（ポリプロピレン）、ＰＥ（ポリエチレン）等の薄膜樹脂フィルム）、不織布、ガラスファイバー等からなる。 The separator has an insulating property, and has a function of preventing a short circuit between the positive electrode and the negative electrode and a function of holding an electrolytic solution. The separator is not particularly limited as long as it can hold or pass the electrolytic solution, but, for example, a microporous polymer film (for example, a thin film resin film such as PP (polypropylene) or PE (polyethylene)), non-woven fabric, It consists of glass fiber etc.
　また、電解液溶媒には、水分を実質的に含まない（例えば、１００ｐｐｍ未満）非水系溶媒が好適に用いられる。非水系溶媒としては、例えば、プロピレンカーボネート、エチレンカーボネート、ジエチルカーボネート、ジメチルカーボネート、メチルエチルカーボネート、ジメトキシエタン、γ－ブチロラクトン、酢酸メチル、蟻酸メチル、トルエン、ヘキサン等が挙げられ、これらのうちの１種を単独でまたは２種以上を組み合わせて用いることができる。 In addition, a non-aqueous solvent substantially free of water (for example, less than 100 ppm) is suitably used as the electrolyte solvent. Examples of non-aqueous solvents include propylene carbonate, ethylene carbonate, diethyl carbonate, dimethyl carbonate, methyl ethyl carbonate, dimethoxyethane, γ-butyrolactone, methyl acetate, methyl formate, toluene, hexane and the like, and one of them is The species can be used alone or in combination of two or more.
　電解質としては、例えば、六フッ化リン酸リチウム、過塩素酸リチウム、四フッ化ホウ酸リチウムのようなリチウム塩等を好適に使用することができる。電解液中の電解質の濃度は、特に限定されないが、０．０１～１Ｍ程度であることが好ましい。 As the electrolyte, for example, lithium hexafluorophosphate, lithium perchlorate, lithium salts such as lithium tetrafluoroborate, and the like can be suitably used. The concentration of the electrolyte in the electrolytic solution is not particularly limited, but is preferably about 0.01 to 1 M.
　次に、本実施形態に係る二次電池劣化検出システムにおける電池セルの劣化検出（劣化診断）方法について説明する。図３は、リチウムイオン電池における時間経過（充放電サイクル）と電極電位の変化との対応を模式的に示している。また、図４は、本実施形態に係る二次電池劣化検出システムにおけるリチウムイオン電池の劣化判定手順を示すフローチャートである。 Next, a method of detecting deterioration (deterioration diagnosis) of the battery cell in the secondary battery deterioration detection system according to the present embodiment will be described. FIG. 3 schematically shows the correspondence between the passage of time (charge-discharge cycle) and the change in electrode potential in a lithium ion battery. Moreover, FIG. 4 is a flowchart which shows the degradation determination procedure of the lithium ion battery in the secondary battery degradation detection system which concerns on this embodiment.
　図３の縦軸は、リチウムイオン電池の電極等の電位（単位はＶ）であり、ここでは充電後における電位を示している。また、横軸は経過時間（サイクル数）である。サイクル数とは、セル電池（リチウムイオン電池）に対する充電および放電の繰り返し回数である。 The vertical axis in FIG. 3 represents the potential (unit: V) of an electrode or the like of a lithium ion battery, and here, the potential after charging is shown. The horizontal axis is elapsed time (cycle number). The cycle number is the number of repetitions of charging and discharging of the cell battery (lithium ion battery).
　本実施形態に係る二次電池劣化検出システム１において、電池モジュール２１ａ～２１ｄを構成する複数の電池セル（リチウムイオン電池）３ａ～３ｓは、電解液として上述した有機溶媒を使用し、正極と負極との間でリチウムイオンが移動することによって充放電を行っている。そのため、電解液に酸あるいはアルカリ水溶液を使用する電池における酸化還元反応に伴う電極の劣化、電解液の電気分解によるイオン電導度の低下は発生しない。 In the secondary battery deterioration detection system 1 according to the present embodiment, the plurality of battery cells (lithium ion batteries) 3a to 3s constituting the battery modules 21a to 21d use the above-described organic solvent as an electrolytic solution, and the positive electrode and the negative electrode Charge and discharge are performed by the movement of lithium ions between them. Therefore, the deterioration of the electrode due to the oxidation-reduction reaction in the battery using an acid or alkaline aqueous solution as the electrolytic solution and the decrease of the ion conductivity due to the electrolysis of the electrolytic solution do not occur.
　一方、リチウムイオン電池では、リチウムイオンが電極に到達し、金属リチウムが析出してリチウムイオン数が減少することで、充放電サイクルの繰り返しにより電池の充電容量、放電容量が低下する。また、リチウムイオン電池は、充放電サイクル後における劣化に伴い、電池の内部で分極が生じ、負極にリチウムイオンが分極することがある。このような分極は、充放電を停止して、時間が経過しても解消されない。 On the other hand, in a lithium ion battery, lithium ions reach the electrode, metal lithium is deposited, and the number of lithium ions decreases, whereby the charge capacity and the discharge capacity of the battery decrease due to the repetition of charge and discharge cycles. In addition, in the lithium ion battery, with the deterioration after charge and discharge cycles, polarization may occur inside the battery and lithium ions may be polarized at the negative electrode. Such polarization stops charging and discharging, and is not eliminated even if time passes.
　そこで、本実施形態に係る二次電池劣化検出システムは、充放電サイクルの進展等により、放電後においても負極に残存するリチウムイオン（Ｌｉ＋）に着目し、不活性化したリチウムイオンの残存に伴う負極電位の低下量を検知して、リチウムイオン電池の劣化を判断・評価する。 Therefore, the secondary battery deterioration detection system according to the present embodiment focuses on lithium ions (Li + ) remaining on the negative electrode even after discharge due to the progress of charge and discharge cycles, etc. The amount of decrease in the negative electrode potential is detected to judge and evaluate the deterioration of the lithium ion battery.
　そのため、二次電池劣化検出システム１の電池セル３ａ～３ｓに負極の電位を測定するための参照電極４５を配置し、負極にリチウムイオンが残存することによる分極の度合いを負極電位に基づいて検知して、検知結果をもとにリチウムイオン電池の劣化の有無を判定する。 Therefore, the reference electrode 45 for measuring the potential of the negative electrode is disposed in the battery cells 3a to 3s of the secondary battery deterioration detection system 1, and the degree of polarization due to lithium ion remaining on the negative electrode is detected based on the negative electrode potential. Then, the presence or absence of deterioration of the lithium ion battery is determined based on the detection result.
　ここで、本実施形態に係る二次電池劣化検出システムの電池セルにおける参照電極の配置について説明する。電池モジュールを構成する複数の電池セルの一部に不具合が発生すると、電池モジュールとしての機能、引いては電池モジュールを搭載した蓄電システム（二次電池システム）がその本来の性能を発揮できなくなる。また、電池モジュールを構成する直列に接続された複数のセル電池間に電池特性のばらつきがあると、最も電池特性の低いセル電池が支配的になり、そのセル電池によって蓄電システム（二次電池システム）全体の特性、信頼性等が制限されることが考えられる。 Here, the arrangement of the reference electrodes in the battery cell of the secondary battery deterioration detection system according to the present embodiment will be described. If a failure occurs in part of a plurality of battery cells constituting the battery module, the function as the battery module, that is, the storage system (secondary battery system) mounted with the battery module can not exhibit its inherent performance. In addition, when there is a variation in battery characteristics among a plurality of cell batteries connected in series constituting the battery module, the cell battery with the lowest battery characteristic becomes dominant, and the storage battery (the secondary battery system) ) It is considered that the overall characteristics, reliability, etc. are limited.
　しかしながら、電池モジュールに組み込んだ複数のセル電池のすべてに参照電極を配置して、それらの負極電位を逐一測定することは、簡易かつ迅速なセル電池の劣化診断を妨げる要因となる。また、複数のセル電池において、さほどバラツキがなく、ほぼ同等に劣化が進行すると仮定した場合、それらのうち代表的なセル電池を監視対象とすることが可能となる。 However, arranging the reference electrodes in all of the plurality of cell batteries incorporated in the battery module and measuring the negative electrode potentials one by one becomes a factor that hinders simple and quick deterioration diagnosis of the cell battery. In addition, in the case where it is assumed that deterioration does not occur so much in the plurality of cell batteries and deterioration progresses almost equally, it is possible to set a representative cell battery among them as a monitoring target.
　そこで、本実施形態に係る二次電池劣化検出システムでは、複数のリチウムイオン電池（セル電池）のうち、使用環境、設置環境等の条件が厳しいと想定される、それら複数のリチウムイオン電池の中心部に位置する１つのセル電池にのみ参照電極４５を配置した構成としている。 Therefore, in the secondary battery deterioration detection system according to the present embodiment, among the plurality of lithium ion batteries (cell batteries), the center of the plurality of lithium ion batteries assumed to have severe conditions such as use environment and installation environment The reference electrode 45 is disposed only in one cell battery located in a part.
　具体的には、上述したように連続して並置あるいは積層された複数のリチウムイオン電池の中心部に位置する１つのセル電池（図１に示す電池モジュール２１ａではセル電池３ｊ、電池モジュール２１ｂではセル電池４ｊ、電池モジュール２１ｃではセル電池５ｊ、電池モジュール２１ｄではセル電池６ｊ）に参照電極を配置する。各セル電池の参照電極とセル監視ユニット（ＣＭＵ）との間には、信号線４９ａ～４９ｄが接続されている。 Specifically, as described above, one cell battery (cell battery 3 j in the battery module 21 a shown in FIG. 1 and cell battery 21 b in the battery module 21 b shown in FIG. 1) located at the center of a plurality of lithium ion batteries arranged in parallel or stacked continuously. A reference electrode is disposed on the cell 4 j, the cell module 5 c in the cell module 21 c, and the cell cell 6 j) in the cell module 21 d. Signal lines 49a to 49d are connected between the reference electrode of each cell battery and the cell monitoring unit (CMU).
　リチウムイオン電池は、図３において符号Ａで示す製造後の初期品の段階において、正極電位と負極電位がともに一定の値を維持する。正極電位と負極電位の電位差がリチウムイオン電池のセル電圧Ｖｃであり、ここでは、参照電極で測定した初期品段階におけるリチウムイオン電池の負極電位をＶ０とする。図３の電位Ｖ１～Ｖｎは、縦軸の０Ｖを基準電位として、参照電極で測定した負極電位の変化（電位低下）を示している。 The lithium ion battery maintains the positive electrode potential and the negative electrode potential at a constant value in the stage of the initial product after production indicated by symbol A in FIG. A cell voltage Vc of the potential difference is lithium ion battery positive electrode potential and negative electrode potential, here, the negative electrode potential of a lithium ion battery in the initial product stage as measured by the reference electrode is V 0. Potentials V 1 to V n in FIG. 3 indicate a change (potential decrease) of the negative electrode potential measured at the reference electrode, with 0 V on the vertical axis as a reference potential.
　上述したように充放電サイクルのサイクル数の増加に伴って、完全放電後においても負極にリチウムイオンが残存し始め、その残存量の増加とともにリチウムイオン電池の負極電位も徐々に低下する。そこで、本実施形態に係る二次電池劣化検出システムでは、バッテリ管理装置（ＢＭＵ）として機能する中央制御部（ＣＰＵ）３１が、参照電極４５で測定された負極電位をもとに、セル電池（リチウムイオン電池）における劣化の発生の有無を判断する。 As described above, with the increase in the number of charge and discharge cycles, lithium ions begin to remain on the negative electrode even after complete discharge, and the negative electrode potential of the lithium ion battery gradually decreases with the increase in the remaining amount. Therefore, in the secondary battery deterioration detection system according to the present embodiment, the central control unit (CPU) 31 functioning as a battery management device (BMU) is configured to use a cell battery (based on the negative electrode potential measured by the reference electrode 45). Judge the occurrence of deterioration in the lithium ion battery).
　そこで中央制御部（ＣＰＵ）３１は、二次電池劣化検出システム１における電池セルの劣化検出（劣化診断）として、最初に図４のステップＳ１１において、劣化判断のための初期設定を行う。すなわち、初期充電された状態のリチウムイオン電池（初期品のセル電池）の負極電位Ｖ０（以降、初期電位ともいう）等を初期データとしてメモリ３３に格納する。このときの負極電位Ｖ０は、充放電サイクルの開始前の状態、あるいは充放電サイクル開始後、相当の時間が経過しているが、負極にリチウムイオンが残存していない状態での負極電位である。 Therefore, the central control unit (CPU) 31 first performs initial setting for deterioration determination in step S11 of FIG. 4 as detection of battery cell deterioration (degradation diagnosis) in the secondary battery deterioration detection system 1. That is, the negative electrode potential V 0 (hereinafter also referred to as an initial potential) and the like of the lithium ion battery in the initial charged state (the cell battery of the initial product) is stored in the memory 33 as initial data. Anode potential V 0 In this case, the charge-discharge cycle of the state before the start or after the charge-discharge cycle start, but have passed considerable time, the negative electrode potential in a state of lithium ion in the negative electrode does not remain, is there.
　中央制御部（ＣＰＵ）３１は、ステップＳ１３において、参照電極で測定された負極電位Ｖ－を、セル監視ユニット（ＣＭＵ）２５ａ～２５ｄおよびインタフェース部３５を介して監視データとして受信する。続くステップＳ１５で、初期品段階におけるリチウムイオン電池の初期電位Ｖ０と、受信した負極電位Ｖ－との差分（Ｖ０－Ｖ－）を算出する。 In step S 13, the central control unit (CPU) 31 receives the negative electrode potential V − measured by the reference electrode as monitoring data via the cell monitoring units (CMU) 25 a to 25 d and the interface unit 35. In step S15, the initial potential V 0 lithium ion battery in the initial product stage, negative electrode potential V received - calculating the - difference between (V 0 -V).
　ステップＳ１７では、電位差分（Ｖ０－Ｖ－）が所定の閾値Ｖthを越えているか否かを判断する。例えば、初回の測定タイミングであれば、初期電位Ｖ０と、参照電極で測定した、図３に示す負極電位Ｖ１との差分（Ｖ０－Ｖ１）が、閾値Ｖthを越えているか否かを判定する。差分（Ｖ０－Ｖ１）が閾値Ｖthを越えていない場合、中央制御部（ＣＰＵ）３１は、セル電池の負極にリチウムイオンが残存することによる劣化は生じていない（正常）と判断する（ステップＳ２３）。 In step S17, the potential difference component (V 0 -V -) to determine whether it exceeds a predetermined threshold value Vth. For example, if it is the first measurement timing, whether the difference (V 0 -V 1 ) between the initial potential V 0 and the negative electrode potential V 1 shown in FIG. 3 measured at the reference electrode exceeds the threshold value Vth Determine If the difference (V 0 -V 1 ) does not exceed the threshold value Vth, the central control unit (CPU) 31 determines that deterioration due to lithium ions remaining in the negative electrode of the cell battery has not occurred (normal) ( Step S23).
　閾値Ｖthは、例えば、電池モジュールに組み込むセル電池（リチウムイオン電池）と同一仕様の複数個のリチウムイオン電池について、あらかじめサイクル試験後において電池容量が初期の容量の例えば５０～８０％となるときの負極電位を測定し、その結果をもとに定めてもよい。 The threshold value Vth is, for example, 50% to 80% of the initial capacity after the cycle test in advance for a plurality of lithium ion batteries of the same specification as the cell battery (lithium ion battery) incorporated in the battery module. The negative electrode potential may be measured and determined based on the result.
　中央制御部（ＣＰＵ）３１は、続くステップＳ２５で、セル電池の総放電時間、セル電圧等をもとに、セル電池が充電を要するモードにあるかを判断する。セル電池が充電を必要としている場合、ステップＳ２７で充電を行い、続くステップＳ２９で、例えば、セル電池の出力電圧が上限電圧に達していれば充電が完了していると判断する。 In the subsequent step S25, the central control unit (CPU) 31 determines whether the cell battery is in a mode requiring charging based on the total discharge time of the cell battery, the cell voltage and the like. If the cell battery needs charging, charging is performed in step S27, and it is determined in step S29 that the charging is completed if, for example, the output voltage of the cell battery has reached the upper limit voltage.
　セル電池の充電後、中央制御部（ＣＰＵ）３１は、ステップＳ１３において、セル監視ユニット（ＣＭＵ）２５ａ～２５ｄおよびインタフェース部３５を介して、次の測定タイミング（２回目）に参照電極で測定した負極電位Ｖ－を監視データとして受信する。そして、ステップＳ１５において、初期電位Ｖ０と、２度目の測定タイミングにおける負極電位Ｖ２との差分（Ｖ０－Ｖ２）を求め、続くステップＳ１７で、その差分（Ｖ０－Ｖ２）が閾値Ｖthを越えているかどうかを判断する。 After charging the cell battery, the central control unit (CPU) 31 measures the reference electrode at the next measurement timing (the second time) via the cell monitoring units (CMU) 25a to 25d and the interface unit 35 in step S13. negative electrode potential V - the received as monitoring data. Then, in step S15, the difference (V 0 -V 2 ) between the initial potential V 0 and the negative electrode potential V 2 at the second measurement timing is determined, and in the subsequent step S17, the difference (V 0 -V 2 ) is It is determined whether the threshold value Vth is exceeded.
　中央制御部（ＣＰＵ）３１は、以降の処理において、ステップＳ１３で、所定の測定タイミングで順次、参照電極で測定した負極電位Ｖ－を監視データとして受信し、ステップＳ１７で、初期電位Ｖ０と、その測定タイミングにおける負極電位との差分（Ｖ０－Ｖ３），…（Ｖ０－Ｖｎ）を求める。 In the subsequent processing, the central control unit (CPU) 31 sequentially receives the negative electrode potential V − measured at the reference electrode at predetermined measurement timing as monitoring data in step S13, and the initial potential V 0 in step S17. Then, the difference (V 0 -V 3 ),... (V 0 -V n ) with the negative electrode potential at the measurement timing is determined.
　なお、リチウムイオン電池（セル電池）は放電時に電圧が下降する傾向にあることから、本実施形態に係る二次電池劣化検出システムでは、上記のようにセル電池の充電後に、初期電位Ｖ０と、参照電極で測定した負極電位Ｖ－との差分を求める。 Since the lithium ion battery (cell battery) tends to drop in voltage during discharge, in the secondary battery deterioration detection system according to the present embodiment, as described above, the initial potential V 0 after charging the cell battery. The difference with the negative electrode potential V − measured at the reference electrode is obtained.
　一方、中央制御部（ＣＰＵ）３１は、ステップＳ１７において、上述した電位の差分が閾値Ｖthを越えていると判断した場合、ステップＳ１９において、充放電サイクルのサイクル数が進展したことで負極にリチウムイオンが残存（リチウムイオンが分極）し、監視対象のセル電池に劣化が生じていると判断する。 On the other hand, when the central control unit (CPU) 31 determines in step S17 that the above-described potential difference exceeds the threshold value Vth, the number of charge and discharge cycles has progressed in step S19 and the lithium number is increased to the negative electrode. It is judged that the ions remain (lithium ions are polarized) and the cell battery to be monitored is deteriorated.
　そして、ステップＳ２１において、液晶表示器等からなる表示部３７に、監視結果として、例えば、電池セルが劣化状態にある電池モジュールを、二次電池劣化検出システムの管理者あるいは保守要員が特定可能に可視表示する。これにより、二次電池劣化検出システムの管理者等は、劣化している電池セルを含む電池モジュール（組電池）の交換等、二次電池劣化検出システムの機能を維持するための対処が必要であると認識できる。 Then, in step S21, as a monitoring result, for example, the administrator or maintenance personnel of the secondary battery deterioration detection system can specify the battery module whose battery cell is in a deteriorated state as a monitoring result in the display unit 37 composed of a liquid crystal display or the like. Make it visible. As a result, the administrator etc. of the secondary battery deterioration detection system needs to take measures to maintain the function of the secondary battery deterioration detection system, such as replacement of a battery module (assembled battery) including a deteriorated battery cell. It can be recognized that there is.
　以上説明したように二次電池劣化検出システムにおいて、セル電池（リチウムイオン電池）に参照電極を配置して負極の電位を測定し、測定した負極電位に基づいてリチウムイオン電池の劣化を判定する。すなわち、放電後でも負極に残存するリチウムイオンの量（分極の度合い）を負極の電位に基づいて検知する構成としたことで、専用のセンサを設けることなく簡易な構成で迅速にセル電池の劣化を判断できる。 As described above, in the secondary battery deterioration detection system, the reference electrode is disposed in the cell battery (lithium ion battery), the potential of the negative electrode is measured, and the deterioration of the lithium ion battery is determined based on the measured negative electrode potential. That is, by detecting the amount (degree of polarization) of lithium ions remaining in the negative electrode even after discharge based on the potential of the negative electrode, the cell battery can be rapidly degraded with a simple configuration without providing a dedicated sensor. Can judge.
　その結果、複数の電池モジュールからなる蓄電システムにおいて、充放電の繰り返しによるサイクル寿命等により負極にリチウムイオンが残存して、電池性能が劣化している電池セルを速やかに検知でき、劣化した電池セルが搭載された電池モジュールの短時間での交換、および蓄電システムの正常な動作の確保が可能となる。 As a result, in a storage system comprising a plurality of battery modules, lithium ions are left on the negative electrode due to cycle life due to repeated charge and discharge, etc., and battery cells degraded in battery performance can be detected promptly and degraded It is possible to replace the mounted battery module in a short time and ensure the normal operation of the storage system.
　また、電池モジュールを構成する複数のセル電池のうち、特定の単一のセル電池にのみ参照電極を配置して、そのセル電池の劣化を検知することで、複数のセル電池の全ての負極電位を逐一測定して劣化の有無を監視するシステム構成と比較して、劣化検知の構成の複雑化を回避できる。 Further, by arranging the reference electrode only on a specific single cell battery among the plurality of cell batteries constituting the battery module and detecting the deterioration of the cell battery, all the negative electrode potentials of the plurality of cell batteries This makes it possible to avoid the complication of the degradation detection configuration as compared with a system configuration in which the presence or absence of degradation is monitored by measuring one by one.
　なお、上記のように複数の電池モジュール（組電池）内の単一のセル電池の劣化を検知した場合、直ちに電池モジュール内のすべての電池を正常な電池と交換する、あるいは電池モジュールそのものを交換することは、劣化検知後、間断なく蓄電システムの正常な動作を維持、継続することに資する。その場合、蓄電システムから取り外したセル電池については、別途、不具合の原因の解明、劣化したセル電池の交換等を行うことで、不具合がなく使用可能な他のセル電池を無駄に廃棄することを防止できる。 As described above, when deterioration of a single cell battery in a plurality of battery modules (assembled batteries) is detected, immediately replace all the batteries in the battery module with a normal battery or replace the battery module itself This contributes to maintaining and continuing the normal operation of the storage system without interruption after detection of deterioration. In that case, with regard to the cell battery removed from the storage system, it is necessary to separately discard the other usable cell batteries without any problems by elucidating the cause of the failure, replacing the deteriorated cell battery, etc. It can prevent.
　本発明は上記の実施形態に限定されず、種々の変形が可能である。以下、上記実施形態の変形例について説明する。 The present invention is not limited to the above embodiment, and various modifications are possible. Hereinafter, the modification of the above-mentioned embodiment is explained.
＜変形例１＞
　上述した実施形態では、初期電位Ｖ０と、所定のタイミングで順次、求めた負極電位との差分を閾値Ｖthと比較した結果をもとに、電池セルの劣化の有無を判断しているが、以下のように電池セルの劣化を予測する構成としてもよい。 <Modification 1>
In the embodiment described above, the presence or absence of the deterioration of the battery cell is determined based on the result of comparing the difference between the initial potential V 0 and the negative electrode potential sequentially determined at a predetermined timing with the threshold value Vth. It is good also as composition of predicting degradation of a battery cell as follows.
　図５は、変形例１に係る電池セルの劣化判断（劣化予測）の方法を説明するための図である。ここでは、図４のステップＳ１３において、充電終了後における負極電位Ｖ－を所定回数、測定し、それらをグラフ上にプロットする（図５において黒丸印で示す電位Ｖ１，Ｖ２，Ｖ３）。そして、それらの点を結んでなる電位の減少傾向をもとに、負極電位Ｖ－の推移を予測する予測線（図５において破線で示す）を引く。 FIG. 5 is a diagram for describing a method of determining deterioration (deterioration prediction) of the battery cell according to the first modification. Here, in step S13 of FIG. 4, the negative electrode potential V − after completion of charging is measured a predetermined number of times, and these are plotted on a graph (potentials V 1 , V 2 , V 3 indicated by black circles in FIG. 5) . Then, based on the decrease in the potential formed by connecting these points, the negative electrode potential V - catching expected line for predicting the change in (indicated by the broken line in FIG. 5).
　中央制御部（ＣＰＵ）３１は、上記の予測線に基づいて、電池セルの初期電位Ｖ０と、予測線における負極電位Ｖ－との差分ΔＶが閾値Ｖthを超えると予測される時間（セル電池に劣化の発生が予測される時期であり、図５において符号Ｂで示す時期）を求める。 Central control unit (CPU) 31, based on the predicted line, the initial potential V 0 cell, the negative electrode potential V in the prediction line - the difference ΔV between exceeds a threshold Vth the predicted time (cell battery It is a time when the occurrence of deterioration is predicted, and the time indicated by a symbol B in FIG.
　このように、負極電位Ｖ－の減少傾向をもとに予測線を引き、それに基づいてセル電池の劣化の発生時期を判断することで、実際の劣化が発生する前に、あらかじめ電池モジュールの交換時期の到来を知ることができる。また、劣化した電池セルにより電池モジュールに不具合が生じる前段階で電池モジュールの交換が可能となり、電池モジュールから電源供給を受けている機器等の突発的な動作停止等を防止できる。 As described above, the prediction line is drawn based on the decreasing tendency of the negative electrode potential V − , and the occurrence time of the deterioration of the cell battery is determined based on it, so that the battery module is replaced in advance before the actual deterioration occurs. We can know the arrival of time. Further, the battery module can be replaced at a stage prior to the occurrence of a defect in the battery module due to the deteriorated battery cell, and it is possible to prevent an abrupt stop of operation or the like of a device receiving power supply from the battery module.
＜変形例２＞
　上記実施形態の図２に示す電池セル（リチウムイオン電池）３ａ～３ｓでは、負極端子４３が突出した側と同一の側から参照電極端子４５ａを露出させているが、露出の形態はこれに限定されない。参照電極端子は、電池セルの任意の位置に配置でき、例えば、図６（ａ）に示す参照電極端子４５ａ～４５ｄのように、平面形状が矩形である電池セル３ａ～３ｓのシート状外装体の４つの周縁部の任意の位置から露出させた構成としてもよい。 <Modification 2>
In the battery cells (lithium ion batteries) 3a to 3s shown in FIG. 2 of the above embodiment, the reference electrode terminal 45a is exposed from the same side as the side where the negative electrode terminal 43 protrudes, but the form of exposure is limited thereto. I will not. The reference electrode terminal can be disposed at any position of the battery cell. For example, as in the reference electrode terminals 45a to 45d shown in FIG. 6A, a sheet-like package of battery cells 3a to 3s having a rectangular planar shape It is good also as composition exposed from arbitrary positions of four peripheral parts.
　また、図６（ｂ）に示すように、正極端子６１と負極端子６３を電池セルの同一端側から露出させた電池セル（リチウムイオン電池）６０においても、平面形状が矩形である電池セルのシート状外装体の４つの周縁部の任意の位置より、参照電極端子６５ａ～６５ｄが露出する構成としてもよい。 Further, as shown in FIG. 6 (b), also in the battery cell (lithium ion battery) 60 in which the positive electrode terminal 61 and the negative electrode terminal 63 are exposed from the same end side of the battery cell, The reference electrode terminals 65a to 65d may be exposed at arbitrary positions of the four peripheral portions of the sheet-like outer package.
＜変形例３＞
　上述した実施形態では、参照電極によって、不活性化したリチウムイオンの残存に伴う負極電位の低下をもとに、リチウムイオン電池の劣化を判断・評価しているが、これに限定されない。例えば、正極板におけるリチウムイオンの吸蔵量の減少に伴う正極電位の低下を参照電極により検知し、その結果をもとにリチウムイオン電池の劣化を判定してもよい。 <Modification 3>
In the embodiment described above, the deterioration of the lithium ion battery is judged and evaluated based on the decrease of the negative electrode potential due to the remaining of the inactivated lithium ion by the reference electrode, but the present invention is not limited thereto. For example, the decrease in positive electrode potential caused by the decrease in lithium ion storage amount in the positive electrode plate may be detected by the reference electrode, and the deterioration of the lithium ion battery may be determined based on the result.
１　二次電池劣化検出システム
３ａ～３ｓ，６０　電池セル（リチウムイオン電池）
１０　蓄電部
２１ａ～２１ｄ　電池モジュール
２５ａ～２５ｄ　セル監視ユニット（ＣＭＵ）
３０　制御部
３１　中央制御部（ＣＰＵ）
３３　メモリ
３５　インタフェース部
３７　表示部
４１，６１　正極端子
４３，６３　負極端子
４５　参照電極
４５ａ～４５ｄ，６５ａ～６５ｄ　参照電極端子
４７　外装体
４９，４９ａ～４９ｄ　信号線
５３　積層体
５５　正極板（正極シート）
５７　負極板（負極シート）
 
 
  1 Secondary battery deterioration detection system 3a to 3s, 60 battery cell (lithium ion battery)
10 power storage units 21a to 21d battery modules 25a to 25d cell monitoring unit (CMU)
30 control unit 31 central control unit (CPU)
33 memory 35 interface unit 37 display unit 41, 61 positive electrode terminal 43, 63 negative electrode terminal 45 reference electrodes 45a to 45d, 65a to 65d reference electrode terminal 47 outer package 49, 49a to 49d signal line 53 laminate 55 positive electrode plate (positive electrode sheet )
57 Negative electrode plate (negative electrode sheet)


Claims (10)

  1. 　正極と負極間で金属イオンをやり取りすることで充放電を行う二次電池の劣化を検出する二次電池劣化検出システムであって、
    　所定電位を基準として前記負極の電位を測定する参照電極と、
    　前記負極の電位に基づいて前記二次電池の劣化の有無を判定する判定手段と、
    を備えることを特徴とする二次電池劣化検出システム。     A secondary battery deterioration detection system for detecting deterioration of a secondary battery that performs charge and discharge by exchanging metal ions between a positive electrode and a negative electrode, comprising:
    A reference electrode for measuring the potential of the negative electrode with reference to a predetermined potential;
    A determination unit that determines the presence or absence of deterioration of the secondary battery based on the potential of the negative electrode;
    A secondary battery deterioration detection system comprising:
  2. 　前記負極の電位は、前記二次電池の放電後における該負極での前記金属イオンの残存量を示していることを特徴とする請求項１に記載の二次電池劣化検出システム。 The secondary battery deterioration detection system according to claim 1, wherein the potential of the negative electrode indicates a remaining amount of the metal ion at the negative electrode after the discharge of the secondary battery.
  3. 　前記判定手段は、前記二次電池の充電完了後における前記負極の電位をもとに該二次電池の劣化状態の有無を判定することを特徴とする請求項１に記載の二次電池劣化検出システム。 The secondary battery deterioration detection according to claim 1, wherein the determination means determines the presence or absence of the deterioration state of the secondary battery based on the potential of the negative electrode after completion of charging of the secondary battery. system.
  4. 　前記判定手段は、時間経過に対する前記負極の電位の変化傾向に基づいて前記二次電池の劣化の発生を予測することを特徴とする請求項１に記載の二次電池劣化検出システム。 The secondary battery deterioration detection system according to claim 1, wherein the determination means predicts the occurrence of the deterioration of the secondary battery based on a change tendency of the potential of the negative electrode with respect to the passage of time.
  5. 　前記参照電極の一方部位が前記二次電池の内部に配置され、他方部位が該二次電池の外部に導出されており、前記一方部位は前記正極と前記負極間において前記金属イオンが移動する経路内に位置することを特徴とする請求項１に記載の二次電池劣化検出システム。 One portion of the reference electrode is disposed inside the secondary battery, and the other portion is led to the outside of the secondary battery, and the one portion is a path along which the metal ion moves between the positive electrode and the negative electrode. The secondary battery deterioration detection system according to claim 1, wherein the system is located inside.
  6. 　前記他方部位のうち前記二次電池の外装体外部へ露出した部分の長さは、前記二次電池の負極端子のうち該外装体外部に露出している部分の長さよりも短いことを特徴とする請求項５に記載の二次電池劣化検出システム。 The length of the portion of the other portion exposed to the outside of the case of the secondary battery is shorter than the length of the portion of the negative electrode terminal of the secondary battery exposed to the outside of the case. The secondary battery deterioration detection system according to claim 5.
  7. 　前記参照電極は、複数の前記二次電池のうち特定の単一の二次電池に配置されていることを特徴とする請求項５に記載の二次電池劣化検出システム。 The secondary battery deterioration detection system according to claim 5, wherein the reference electrode is disposed in a specific single secondary battery among a plurality of the secondary batteries.
  8. 　前記参照電極は、前記二次電池のシート状外装体周縁部の任意の位置より該外装体の外部へ露出していることを特徴とする請求項５に記載の二次電池劣化検出システム。 The system for detecting deterioration of a secondary battery according to claim 5, wherein the reference electrode is exposed to the outside of the outer package at an arbitrary position of a sheet-like outer package peripheral portion of the secondary battery.
  9. 　前記二次電池はリチウムイオン電池であり、前記金属イオンはリチウムイオンであることを特徴とする請求項１から８のいずれか１項に記載の二次電池劣化検出システム。 The secondary battery degradation detection system according to any one of claims 1 to 8, wherein the secondary battery is a lithium ion battery, and the metal ion is lithium ion.
  10. 　さらに、前記二次電池の劣化に対応した所定の警報を発する手段を備えることを特徴とする請求項１に記載の二次電池劣化検出システム。
     
          The system for detecting deterioration of a secondary battery according to claim 1, further comprising means for issuing a predetermined alarm corresponding to the deterioration of the secondary battery.

PCT/JP2018/022916 2017-09-22 2018-06-15 Secondary battery deterioration detection system WO2019058666A1 (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
JP2019543414A JPWO2019058666A1 (en) 2017-09-22 2018-06-15 Secondary battery deterioration detection system

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP2017-182216 2017-09-22
JP2017182216 2017-09-22

Publications (1)

Publication Number Publication Date
WO2019058666A1 true WO2019058666A1 (en) 2019-03-28

Family

ID=65809630

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2018/022916 WO2019058666A1 (en) 2017-09-22 2018-06-15 Secondary battery deterioration detection system

Country Status (2)

Country Link
JP (1) JPWO2019058666A1 (en)
WO (1) WO2019058666A1 (en)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111948428A (en) * 2020-08-10 2020-11-17 南京莱迪新能源科技有限公司 Device for rapidly detecting voltage of lithium ion battery for new energy storage on line
WO2022034671A1 (en) * 2020-08-13 2022-02-17 ＴｅｒａＷａｔｔ Ｔｅｃｈｎｏｌｏｇｙ株式会社 Deterioration state estimation device, deterioration state estimation method, program, and power supply device for anode-free lithium battery equipped with same
CN114527172A (en) * 2022-02-21 2022-05-24 蜂巢能源科技股份有限公司 Method for evaluating stability of battery positive electrode material

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013054939A (en) * 2011-09-05 2013-03-21 Toyota Motor Corp Battery system
JP2013247003A (en) * 2012-05-28 2013-12-09 Sony Corp Charge control device for secondary battery, charge control method for secondary battery, charged state estimation device for secondary battery, charged state estimation method for secondary battery, deterioration degree estimation device for secondary battery, deterioration degree estimation method for secondary battery, and secondary battery device
US20160308260A1 (en) * 2013-12-13 2016-10-20 GM Global Technology Operations LLC Incorporating reference electrodes into battery pouch cells
JP2017069011A (en) * 2015-09-30 2017-04-06 株式会社日立製作所 Lifetime controlled secondary battery system
JP2017143026A (en) * 2016-02-12 2017-08-17 スズキ株式会社 Secondary battery soundness estimation method in system combining fuel cell and secondary battery, and system combining fuel cell and secondary battery

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2013054939A (en) * 2011-09-05 2013-03-21 Toyota Motor Corp Battery system
JP2013247003A (en) * 2012-05-28 2013-12-09 Sony Corp Charge control device for secondary battery, charge control method for secondary battery, charged state estimation device for secondary battery, charged state estimation method for secondary battery, deterioration degree estimation device for secondary battery, deterioration degree estimation method for secondary battery, and secondary battery device
US20160308260A1 (en) * 2013-12-13 2016-10-20 GM Global Technology Operations LLC Incorporating reference electrodes into battery pouch cells
JP2017069011A (en) * 2015-09-30 2017-04-06 株式会社日立製作所 Lifetime controlled secondary battery system
JP2017143026A (en) * 2016-02-12 2017-08-17 スズキ株式会社 Secondary battery soundness estimation method in system combining fuel cell and secondary battery, and system combining fuel cell and secondary battery

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN111948428A (en) * 2020-08-10 2020-11-17 南京莱迪新能源科技有限公司 Device for rapidly detecting voltage of lithium ion battery for new energy storage on line
CN111948428B (en) * 2020-08-10 2023-05-26 南京莱迪新能源科技有限公司 Device for online and rapid voltage detection of lithium ion battery for new energy storage
WO2022034671A1 (en) * 2020-08-13 2022-02-17 ＴｅｒａＷａｔｔ Ｔｅｃｈｎｏｌｏｇｙ株式会社 Deterioration state estimation device, deterioration state estimation method, program, and power supply device for anode-free lithium battery equipped with same
CN114527172A (en) * 2022-02-21 2022-05-24 蜂巢能源科技股份有限公司 Method for evaluating stability of battery positive electrode material
CN114527172B (en) * 2022-02-21 2024-05-03 蜂巢能源科技股份有限公司 Evaluation method for stability of battery anode material

Also Published As

Publication number Publication date
JPWO2019058666A1 (en) 2020-11-26

Similar Documents

Publication Publication Date Title
JP5315369B2 (en) Abnormally charged state detection device and inspection method for lithium secondary battery
US9653724B2 (en) Secondary battery, and secondary battery module and secondary battery pack comprising the same
US9465077B2 (en) Battery health monitoring system and method
JP6021087B2 (en) System for secondary battery including mixed positive electrode material, management apparatus and method for secondary battery including mixed positive electrode material
KR101487495B1 (en) Apparatus for estimating state of charge of secondary battery including blended cathode material and Method thereof
JP2014222603A (en) Inspection method for battery
EP3145021B1 (en) Secondary-battery monitoring device and method for predicting capacity of secondary battery
KR100809453B1 (en) The monitering system for charging and discharging lithium rechargable battery pack
KR20100075913A (en) Lithium rechargeable cell with reference electrode for state of health monitoring
US9453887B2 (en) Method of selecting used secondary battery and method of manufacturing battery pack
KR20130139759A (en) Apparatus for estimating state of charge of secondary battery including blended cathode material and method thereof
JP2009145137A (en) Inspection method of secondary battery
CN103797679A (en) Secondary battery control device
JP2016126943A (en) Power storage device and power storage system
JP6822465B2 (en) Deterioration judgment method and power storage system
KR20200059483A (en) Pressure short testing device for detecting a low voltage battery cell
WO2019058666A1 (en) Secondary battery deterioration detection system
KR102470882B1 (en) Unit battery module and measuring for state of health thereof
JP2003243042A (en) Detecting method and device for degree of deterioration of lithium battery as component of package battery
US10020546B2 (en) Device for managing an accumulator
US20130252070A1 (en) Dummy battery cell for safe testing of battery systems
JP2019145342A (en) Diagnostic device and control device
KR102196270B1 (en) Method and apparatus for detecting short of a battery cell
US20230402666A1 (en) Abnormality detection method, abnormality detection device, energy storage apparatus, and computer program
WO2015059738A1 (en) Secondary battery control apparatus and secondary battery control method

Legal Events

Date Code Title Description
121 Ep: the epo has been informed by wipo that ep was designated in this application

Ref document number: 18857872

Country of ref document: EP

Kind code of ref document: A1

ENP Entry into the national phase

Ref document number: 2019543414

Country of ref document: JP

Kind code of ref document: A

NENP Non-entry into the national phase

Ref country code: DE

122 Ep: pct application non-entry in european phase

Ref document number: 18857872

Country of ref document: EP

Kind code of ref document: A1