JP5705046B2 - Power system - Google Patents
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- JP5705046B2 JP5705046B2 JP2011143877A JP2011143877A JP5705046B2 JP 5705046 B2 JP5705046 B2 JP 5705046B2 JP 2011143877 A JP2011143877 A JP 2011143877A JP 2011143877 A JP2011143877 A JP 2011143877A JP 5705046 B2 JP5705046 B2 JP 5705046B2
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- 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
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- 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
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Description
本発明は、非水系二次電池で構成された組電池の電源システムに関する。 The present invention relates to a power supply system for a battery pack composed of a non-aqueous secondary battery.
リチウムイオン電池が製品化されるまで主流であったニッケル・カドミウム電池やニッケル・水素電池等のアルカリ水溶液系二次電池は、定電流充電方式が一般的であった（例えば、特許文献１参照）。
近年急激に増加しているリチウムイオン電池等の非水系二次電池は、正極にコバルト酸リチウム、ニッケル酸リチウム、マンガン酸リチウム、又は、それらを組み合わせた複合材料を用い、負極にグラファイトやハードカーボン等の炭素材料を用い、電解質にエチレンカーボネート等の有機溶媒を使用している。
この非水系二次電池では、充電末期にて電圧が上昇する際、正極及び負極が極めて強い酸化・還元状態におかれ、アルカリ水溶液系二次電池に比べて材料が非常に不安定化しやすいので、一定の電圧以上まで過充電すると正極では電解液の酸化・結晶構造の破壊により発熱し、負極では金属リチウムが析出し、電池を急激に劣化させる等の不具合を招くおそれがある。また、過充電時の電解液分解は電池内のガス発生や不可逆容量の増加を招き、これも電池の劣化の要因となる。
この非水系二次電池を、従来のアルカリ水溶液系二次電池と同じ定電流充電方式で充電すると、過充電になりやすく、特に、充電電流が大きくなる程、分極により電圧が上昇し、過充電の傾向が強くなり、電池の故障を招くおそれがあった。このため、従来の非水系二次電池では、一定電流で充電した後、一定の電圧に達すると電流を減少させ、所定の電流値に達したら充電を終了する定電流定電圧充電方式を採用している（例えば、特許文献２参照）。
A constant current charging method is generally used for alkaline aqueous secondary batteries such as nickel / cadmium batteries and nickel / hydrogen batteries, which have been mainstream until lithium ion batteries are commercialized (see, for example, Patent Document 1). .
Non-aqueous secondary batteries, such as lithium-ion batteries, which have been increasing rapidly in recent years, use lithium cobaltate, lithium nickelate, lithium manganate, or a composite material combining them for the positive electrode and graphite or hard carbon for the negative electrode. Etc., and an organic solvent such as ethylene carbonate is used for the electrolyte.
In this non-aqueous secondary battery, when the voltage rises at the end of charging, the positive electrode and the negative electrode are placed in a very strong oxidation / reduction state, and the material is much more unstable than the alkaline aqueous battery. If the battery is overcharged to a certain voltage or more, heat is generated at the positive electrode due to oxidation of the electrolyte and destruction of the crystal structure, and metal lithium is deposited at the negative electrode, which may lead to problems such as rapid deterioration of the battery. In addition, decomposition of the electrolyte during overcharging causes gas generation in the battery and an increase in irreversible capacity, which also causes deterioration of the battery.
If this non-aqueous secondary battery is charged with the same constant current charging method as the conventional alkaline aqueous battery, it tends to be overcharged.In particular, as the charging current increases, the voltage increases due to polarization, and overcharging occurs. There was a risk that battery failure would occur. For this reason, the conventional non-aqueous secondary battery employs a constant current / constant voltage charging method in which, after charging at a constant current, the current is reduced when a constant voltage is reached, and the charging is terminated when a predetermined current value is reached. (For example, refer to Patent Document 2).
しかしながら、定電流定電圧充電方式は、充電時間が長くなることに加え、定電流充電と定電圧充電とを行う構成、及び、充電切替を行う構成を具備する必要があるため、部品点数が多くなり、充電装置が高価になってしまう。
しかも、定電流定電圧充電方式で組電池を充電すると、組電池内の各セルの僅かな特性差でも定電圧充電領域で各セルの電圧が大きくばらつき、過充電に至るセルが生じるため、この電圧ばらつきを解消するための充電バランス回路が必要であった。このため、組電池の部品点数が多くなり、高価になってしまう。
However, the constant current / constant voltage charging method has a large number of parts because it needs to have a structure for performing constant current charging and constant voltage charging and a structure for switching charging in addition to a long charging time. Therefore, the charging device becomes expensive.
In addition, when the battery pack is charged by the constant current / constant voltage charging method, even a slight difference in characteristics of each cell in the battery pack causes the voltage of each cell to vary greatly in the constant voltage charging region, resulting in cells leading to overcharging. A charge balance circuit was necessary to eliminate the voltage variation. For this reason, the number of parts of an assembled battery will increase and it will become expensive.
本発明は、上述した事情を鑑みてなされたものであり、簡易な構成で、過充電を回避して充電することができる非水系二次電池の電源システムを提供することを目的としている。 The present invention has been made in view of the above-described circumstances, and an object thereof is to provide a power supply system for a non-aqueous secondary battery that can be charged while avoiding overcharging with a simple configuration.
上述した課題を解決するため、本発明は、非水系二次電池で構成された複数のセルを有する組電池と、組電池の充電・放電を制御する制御装置と、前記組電池を充電・放電する充・放電装置とを備え、各セルの正極にオリビン構造のリチウム遷移金属複合酸化物を用いるとともに負極にグラファイト系材料を用い、前記充・放電装置は、前記組電池を定電流充電し、前記制御装置は、充・放電停止回路を備え、組電池の充電時は該充・放電停止回路によって定電流充電中の各セルの電圧をモニターし、各セルのいずれか１セルの電圧が所定の電圧値に達すると充電を停止させることのみ行うことを特徴とする。
この構成によれば、組電池の充電時の電圧の上昇が緩やかであり、充電末期に急激に電圧が上昇する特性が得られ、充電バランス回路を必要とせずに良好なサイクル寿命で充電でき、且つ、定電流定電圧充電方式に比べて充電時間の短縮に有利である。このため、簡易な構成で、過充電を回避して充電することができ、充電時間も短縮できる。
In order to solve the above-described problems, the present invention provides an assembled battery having a plurality of cells composed of non-aqueous secondary batteries, a control device that controls charging / discharging of the assembled battery, and charging / discharging the assembled battery. And using a lithium transition metal composite oxide having an olivine structure for the positive electrode of each cell and using a graphite-based material for the negative electrode, the charge / discharge device charges the assembled battery at a constant current, The control device includes a charge / discharge stop circuit, and when charging the assembled battery, the charge / discharge stop circuit monitors the voltage of each cell during constant current charging, and the voltage of any one of the cells is predetermined. It is characterized in that the charging is only stopped when the voltage value is reached.
According to this configuration, the voltage rise at the time of charging the assembled battery is gradual, a characteristic that the voltage suddenly rises at the end of charging can be obtained, and it can be charged with a good cycle life without requiring a charge balance circuit, In addition, it is advantageous in shortening the charging time as compared with the constant current constant voltage charging method. For this reason, with a simple configuration, charging can be performed while avoiding overcharging, and the charging time can be shortened.
上記構成において、前記充・放電装置は、前記組電池を放電し、前記制御装置は、前記充・放電停止回路によって各セルのいずれか１セルの電圧が予め定めた下限電圧に達すると放電を停止させるようにしても良い。この構成によれば、簡易な構成で、過放電を回避することができる。
また、上記構成において、前記組電池は、各セルの電圧ばらつきを解消する充電バランス回路を備えることなく各セルを接続して構成されるようにしても良い。この構成によれば、部品点数が少なく、安価に構成することができる。
また、上記構成において、前記組電池は、一定の電流で充電した場合に、満充電の９０％以上となる充電末期で、充電末期以前よりも電池電圧が急上昇する特性に形成され、前記所定の電圧値は、前記充電末期内の電圧値に設定される値であり、即ち、３．４Ｖ〜３．６Ｖの間で任意に設定される値である。この構成によれば、過充電を確実に回避しつつ、ほぼ満充電の状態で充電停止させることができる。
また、予め定めた放電時の下限電圧とは２．０Ｖ〜２．２Ｖの間で任意に設定される値である。この構成によれば、過放電を確実に回避することができる。
In the above configuration, the charging / discharging device discharges the assembled battery, and the control device discharges when the voltage of any one of the cells reaches a predetermined lower limit voltage by the charging / discharging stop circuit. You may make it stop. According to this configuration, overdischarge can be avoided with a simple configuration.
Further, in the above configuration, the assembled battery may be configured by connecting cells without including a charge balance circuit that eliminates voltage variations of the cells. According to this configuration, the number of parts is small and the configuration can be made inexpensively.
Further, in the above configuration, the assembled battery is formed to have a characteristic in which the battery voltage rises more rapidly than before the end of charge at the end of charge, which is 90% or more of full charge when charged with a constant current. The voltage value is a value that is set to a voltage value within the end of charging, that is, a value that is arbitrarily set between 3.4V and 3.6V. According to this configuration, charging can be stopped in a substantially fully charged state while reliably avoiding overcharging.
Further, the predetermined lower limit voltage at the time of discharging is a value arbitrarily set between 2.0V and 2.2V. According to this configuration, overdischarge can be reliably avoided.
本発明では、非水系二次電池で構成された各セルの正極にオリビン構造のリチウム遷移金属複合酸化物を用いるとともに負極にグラファイト系材料を用い、充・放電装置は、各セルを有する組電池を定電流充電し、制御装置は、充・放電停止回路を備え、組電池の充電時は該充・放電停止回路によって定電流充電中の各セルの電圧をモニターし、各セルのいずれか１セルの電圧が所定の電圧値に達すると充電を停止させることのみ行うので、簡易な構成で、過充電を回避して充電することができ、充電時間も短縮できる。また、充電バランス回路を必要とせずに良好なサイクル寿命で充電できる。 In the present invention, a lithium transition metal composite oxide having an olivine structure is used for the positive electrode of each cell composed of a non-aqueous secondary battery, and a graphite-based material is used for the negative electrode. The control device includes a charge / discharge stop circuit, and monitors the voltage of each cell during the constant current charge by the charge / discharge stop circuit when charging the assembled battery. Since the charging is only stopped when the cell voltage reaches a predetermined voltage value, the battery can be charged while avoiding overcharging with a simple configuration, and the charging time can be shortened. Moreover, it can charge with a favorable cycle life, without requiring a charge balance circuit.
以下、図面を参照して本発明の一実施の形態について説明する。
図１は、本発明の実施形態に係る電源システム１０を示す図である。
この電源システム１０は、電力で動作する機器の電源となる組電池モジュール１１と、組電池モジュール１１を充電する充・放電装置２１とを備えている。
組電池モジュール１１は、複数のセル（単電池とも言う）１２を有する組電池１３と、組電池１３の充電／放電を制御する充・放電制御装置（制御装置）３１とを有しており、充・放電制御装置３１は、各セル１２に電圧モニター線３２を介して接続される電圧計３３を用いて各セル１２をモニターし、充・放電停止回路３５によって各セル１２のいずれか１セルの電圧が所定の電圧値に達すると、充電をリレースイッチ３４によって停止させる構成としたものである。
図２は、セル１２の略図を示している。各セル１２は、充電・放電に伴ってリチウムイオンを放出・吸蔵する正極活物質を有する正極１４と、充電・放電に伴ってリチウムイオンを吸蔵・放出する負極活物質を有する負極１５と、正極１４と負極１５との間に設けられるセパレータと、正極１４と負極１５とを満たす非水電解液（図には現れず）とを有し、これらはラミネート外装体１６に封入され、非水系二次電池の一種であるリチウムイオン電池として構成されている。
Hereinafter, an embodiment of the present invention will be described with reference to the drawings.
FIG. 1 is a diagram showing a power supply system 10 according to an embodiment of the present invention.
The power supply system 10 includes an assembled battery module 11 that serves as a power source for a device that operates on electric power, and a charging / discharging device 21 that charges the assembled battery module 11.
The assembled battery module 11 includes an assembled battery 13 having a plurality of cells (also referred to as single cells) 12, and a charge / discharge control device (control device) 31 that controls charging / discharging of the assembled battery 13. The charge / discharge control device 31 monitors each cell 12 using a voltmeter 33 connected to each cell 12 via a voltage monitor line 32, and any one cell of each cell 12 by a charge / discharge stop circuit 35. When the voltage reaches a predetermined voltage value, the charging is stopped by the relay switch 34.
FIG. 2 shows a schematic diagram of the cell 12. Each cell 12 includes a positive electrode 14 having a positive electrode active material that releases and occludes lithium ions as it is charged and discharged, a negative electrode 15 that has a negative electrode active material that occludes and releases lithium ions as it is charged and discharged, and a positive electrode 14 and a negative electrode 15 and a non-aqueous electrolyte solution (not shown in the figure) that fills the positive electrode 14 and the negative electrode 15. It is comprised as a lithium ion battery which is a kind of secondary battery.
本実施形態の組電池モジュール１１に用いられるセル１２は、各セル１２の正極１４にオリビン構造のリチウム遷移金属複合酸化物を用いるとともに負極１５にグラファイト系材料を用いたものである。
詳述すると、本実施形態では、正極活物質にオリビン型リン酸鉄リチウム（ＬｉＦｅＰＯ４）を用い、導電剤にアセチレンブラック粉状品を用い、バインダーとしてポリフッ化ビニリデン（ＰＶＤＦ）を用い、ディスパー付プラネタリーミキサーで攪拌混合してペーストを調整し、正極１４の基材となる厚み２０μｍのアルミニウム箔に塗布し、乾燥後にプレスして所定サイズにサイジングすることにより、正極１４に用いる正極板を作製している。
また、負極活物質にグラファイトを用い、増粘剤としてカルボキシメチルセルロース（ＣＭＣ）水溶液を用い、結着剤としてスチレンブタジエンラバーを用い、粘度調整用にイオン交換水を加えて、ディスパー付プラネタリーミキサーで攪拌混合してペースト化し、負極１５の基材となる厚み１０μｍの銅（Ｃｕ）箔に塗布し、乾燥後にプレスして所定サイズにサイジングすることにより、負極１５に用いる負極板を作製している。
The cell 12 used in the assembled battery module 11 of the present embodiment uses a lithium transition metal composite oxide having an olivine structure for the positive electrode 14 of each cell 12 and a graphite material for the negative electrode 15.
Specifically, in the present embodiment, olivine type lithium iron phosphate (LiFePO 4 ) is used as the positive electrode active material, acetylene black powder is used as the conductive agent, polyvinylidene fluoride (PVDF) is used as the binder, and a disperser is attached. A paste is prepared by stirring and mixing with a planetary mixer, applied to an aluminum foil having a thickness of 20 μm, which becomes the base material of the positive electrode 14, dried, pressed and sized to a predetermined size, thereby producing a positive electrode plate used for the positive electrode 14. doing.
Also, graphite is used for the negative electrode active material, carboxymethyl cellulose (CMC) aqueous solution is used as the thickener, styrene butadiene rubber is used as the binder, ion-exchanged water is added for viscosity adjustment, and a planetary mixer with a disper is used. The negative electrode plate used for the negative electrode 15 is produced by making a paste by stirring and mixing, applying it to a copper (Cu) foil having a thickness of 10 μm as a base material of the negative electrode 15, pressing after drying and sizing to a predetermined size. .
セパレータには、ポリエチレン（ＰＥ）製の２５μｍからなる微多孔膜を用い、非水電解液には、エチレンカーボネートとエチルメチルカーボネートを体積比で３：７とした混合溶媒に、電解質として六フッ化燐酸リチウム（ＬｉＰＦ６）を溶解した電解液を用いている。
そして、正極板（正極１４）と負極板（負極１５）とをセパレータを介して交互に積層して積層体を形成し、これらを前記電解液と共にラミネート外装体１６（図２参照）に封入することによって、定格出力電圧３．２Ｖ、定格容量２０Ａｈのラミネートセル（以下、単に「セル」と言う）を作製している。
The separator uses a microporous membrane made of polyethylene (PE) made of 25 μm, and the non-aqueous electrolyte is a mixed solvent of ethylene carbonate and ethyl methyl carbonate in a volume ratio of 3: 7, and hexafluoride as an electrolyte. An electrolytic solution in which lithium phosphate (LiPF 6 ) is dissolved is used.
And a positive electrode plate (positive electrode 14) and a negative electrode plate (negative electrode 15) are laminated | stacked alternately via a separator, a laminated body is formed, and these are enclosed with the said electrolyte solution in the laminate exterior body 16 (refer FIG. 2). Thus, a laminate cell (hereinafter simply referred to as “cell”) having a rated output voltage of 3.2 V and a rated capacity of 20 Ah is manufactured.
図１に示すように、このように作製した８個のセル１２が直列に接続され、これらセル１２の両端に入出力端子１７，１８が接続され、各セル１２に電圧モニター線３２を介して電圧計３３が接続され、セル１２と一方の入出力端子１７との間の導通を選択的に遮断する単一のリレースイッチ３４、及び、このリレースイッチ３４を開閉する充・放電停止回路３５が設けられることによって作製される２４Ｖ系の組電池を充・放電制御装置３１で制御することが出来る。 As shown in FIG. 1, the eight cells 12 produced in this way are connected in series, and input / output terminals 17 and 18 are connected to both ends of the cells 12, and each cell 12 is connected to each cell 12 via a voltage monitor line 32. A voltmeter 33 is connected, a single relay switch 34 that selectively cuts off conduction between the cell 12 and one input / output terminal 17, and a charge / discharge stop circuit 35 that opens and closes the relay switch 34. The charge / discharge control device 31 can control the 24V battery pack produced by being provided.
充・放電制御装置３１は、上記電圧計３３、リレースイッチ（遮断部材）３４及び充・放電停止回路３５によって構成される。電圧計３３は、各セル１２の電圧（セル電圧）を各々測定し、測定結果を充・放電停止回路３５に出力するものであり、充・放電停止回路３５は、電圧計３３を介して通知される各セル電圧をモニターし、記憶部（図示せず）に記憶される所定の充電電圧又は所定の放電電圧に応じてリレースイッチ３４を開放又は閉成する。
このリレースイッチ３４が閉成のときは、組電池１３と入出力端子１７とが接続するので、組電池１３の充電や放電が可能となり、リレースイッチ３４が開放のときは、組電池１３と入出力端子１７とが切り離されるので、充電停止や放電停止となる。
The charge / discharge control device 31 includes the voltmeter 33, a relay switch (interrupt member) 34, and a charge / discharge stop circuit 35. The voltmeter 33 measures the voltage (cell voltage) of each cell 12 and outputs the measurement result to the charge / discharge stop circuit 35. The charge / discharge stop circuit 35 notifies the voltmeter 33 via the voltmeter 33. Each cell voltage is monitored, and the relay switch 34 is opened or closed according to a predetermined charging voltage or a predetermined discharging voltage stored in a storage unit (not shown).
When the relay switch 34 is closed, the assembled battery 13 and the input / output terminal 17 are connected, so that the assembled battery 13 can be charged or discharged. When the relay switch 34 is opened, the assembled battery 13 is turned on. Since the output terminal 17 is disconnected, charging is stopped or discharging is stopped.
上記したように、本実施形態では、各セル１２の正極１４にオリビン構造のリチウム遷移金属複合酸化物を用いるとともに負極１５にグラファイト系材料を用いている。
オリビン構造のリチウム遷移金属複合酸化物は、結晶中の全ての酸素がリンと共有結合し、強固なリン酸塩（ＰＯ４ ３−）ポリアニオンを構成している。このため、従来のリチウムイオン電池の電極に使用されるコバルト酸リチウム、ニッケル酸リチウム、マンガン酸リチウム等に比べて非常に安定しており、熱安定性が高く、過充電や高温に対して高い安全性を有している。
As described above, in the present embodiment, a lithium transition metal composite oxide having an olivine structure is used for the positive electrode 14 of each cell 12 and a graphite-based material is used for the negative electrode 15.
In the lithium transition metal composite oxide having an olivine structure, all oxygen in the crystal is covalently bonded to phosphorus to form a strong phosphate (PO 4 3− ) polyanion. Therefore, it is very stable compared to lithium cobaltate, lithium nickelate, lithium manganate, etc. used for the electrodes of conventional lithium ion batteries, has high thermal stability, and is high against overcharge and high temperature. It has safety.
図３及び図４は、正極１４にオリビン型リン酸鉄リチウムを用い、負極１５にグラファイトを用いたリチウムイオン電池の充電特性、つまり、本実施形態のセル１２の充電特性を示している。ここで、図３は縦軸を電圧、横軸を充電容量で示した図であり、図４は縦軸の主軸を「電圧」、第２軸を「充電電流／充電容量」、横軸を充電時間で示した図である。これら図３，図４は、０．５ＣＡの一定電流で充電（定電流充電）した場合の電圧ＶＡ、「充電電流／充電容量」ＪＡ、電流ＩＡ、及び、１．０ＣＡの一定電流で充電（定電流充電）した場合の電圧ＶＢ、「充電電流／充電容量」ＪＢ、電流ＩＢを示している。
図３及び図４に示すように、本実施形態のセル１２は、充電末期付近までは電圧ＶＡの上昇が非常に緩やかであり、充電末期に急激に電圧ＶＡ，ＶＢが上昇している。ここで、充電末期とは、満充電の少なくとも９０％以上の領域である。
このように充電末期で、充電末期以前よりも電圧が急上昇する特性を有するので、一定の電流で充電し、充電末期内の所定の上限電圧（充電停止電圧）Ｖ１（図３、図４では３．６Ｖ）で充電を停止するようにすれば、過充電を避けつつ満充電に近い充電量が得られる。
また、１．０ＣＡ充電の場合、０．５ＣＡ充電よりも短時間で充電できるが、このような急速充電においても、充電末期付近までは電圧の上昇が非常に緩やかであり、充電末期に急激に電圧が上昇する現象は変わらなかった。このため、定電流の急速充電でも、同じ充電方法で、過充電を避けつつ満充電に近い充電量を得ることができる。
3 and 4 show the charging characteristics of a lithium ion battery using olivine-type lithium iron phosphate as the positive electrode 14 and graphite as the negative electrode 15, that is, the charging characteristics of the cell 12 of the present embodiment. Here, FIG. 3 is a diagram in which the vertical axis indicates voltage and the horizontal axis indicates charge capacity. FIG. 4 shows the main axis of the vertical axis as “voltage”, the second axis as “charge current / charge capacity”, and the horizontal axis as It is the figure shown by charge time. FIGS. 3 and 4 show a voltage VA, a “charging current / charge capacity” JA, a current IA, and a constant current of 1.0 CA when charged with a constant current of 0.5 CA (constant current charging) ( A voltage VB, “charging current / charging capacity” JB, and current IB in the case of constant current charging) are shown.
As shown in FIGS. 3 and 4, in the cell 12 of the present embodiment, the voltage VA increases very slowly until near the end of charging, and the voltages VA and VB rapidly increase at the end of charging. Here, the end of charging is an area of at least 90% of full charge.
In this way, the voltage at the end of charging has a characteristic that the voltage rises more rapidly than before the end of charging. Therefore, charging is performed with a constant current, and a predetermined upper limit voltage (charging stop voltage) V1 (3 in FIGS. If the charging is stopped at .6 V), a charging amount close to full charging can be obtained while avoiding overcharging.
Further, in the case of 1.0 CA charging, charging can be performed in a shorter time than 0.5 CA charging, but even in such rapid charging, the voltage rise is very gradual until near the end of charging, and suddenly reaches the end of charging. The phenomenon of increasing voltage did not change. For this reason, even with constant current rapid charge, the same charge method can be used to obtain a charge amount close to full charge while avoiding overcharge.
本実施形態では、充・放電装置２１を、一定の電流で充電する定電流充電の充・放電装置とし、充・放電制御装置３１には、上限電圧Ｖ１として、満充電時のセル電圧である３．６Ｖの電圧値を設定し、この設定情報を、充・放電停止回路３５の記憶部に記憶させるようにしている。また、充・放電停止回路３５の記憶部には、セル１２の下限電圧Ｖ２として２．２Ｖの電圧値も記憶させるようにしている。 In the present embodiment, the charging / discharging device 21 is a charging / discharging device for constant current charging that charges at a constant current, and the charging / discharging control device 31 has a cell voltage at the time of full charging as the upper limit voltage V1. A voltage value of 3.6 V is set, and this setting information is stored in the storage unit of the charge / discharge stop circuit 35. The storage unit of the charge / discharge stop circuit 35 also stores a voltage value of 2.2 V as the lower limit voltage V2 of the cell 12.
図５は、充・放電制御装置３１の動作を示すフローチャートである。なお、前提として、リレースイッチ３４は通常、閉成されている。
充・放電制御装置３１において、組電池モジュール１１の充電時や放電時（ステップＳ１１）、電圧計３３は、各セル１２の電圧を測定し（ステップＳ１２）。充・放電停止回路３５は、各セル１２の電圧をモニターし、いずれか１セルの電圧が、予め記憶された上限電圧Ｖ１以上か否かを判定する（ステップＳ１３）。そして、いずれか１セルの電圧が上限電圧Ｖ１以上の場合に（ステップＳ１３：ＹＥＳ）、充・放電停止回路３５は、リレースイッチ３４を開放する（ステップＳ１４）。これにより、充電によって、いずれか１セルの電圧が上限電圧Ｖ１に達すると、それ以上の充電が直ちに停止される。
一方、いずれのセルの電圧も上限電圧Ｖ１未満の場合（ステップＳ１３：ＮＯ）、充・放電停止回路３５は、いずれかのセル１２の電圧が、予め記憶された下限電圧Ｖ２未満か否かを判定する（ステップＳ１５）。そして、いずれかのセル１２の電圧が下限電圧Ｖ２未満の場合に（ステップＳ１５：ＹＥＳ）、充・放電停止回路３５は、リレースイッチ３４を開放する（ステップＳ１６）。これにより、放電によって、いずれか１セルの電圧が下限電圧Ｖ２に達した時点で、それ以上の放電が直ちに停止される。
FIG. 5 is a flowchart showing the operation of the charge / discharge control device 31. As a premise, the relay switch 34 is normally closed.
In the charging / discharging control device 31, when the assembled battery module 11 is charged or discharged (step S11), the voltmeter 33 measures the voltage of each cell 12 (step S12). The charge / discharge stop circuit 35 monitors the voltage of each cell 12, and determines whether the voltage of any one cell is equal to or higher than the upper limit voltage V1 stored in advance (step S13). When the voltage of any one cell is equal to or higher than the upper limit voltage V1 (step S13: YES), the charge / discharge stop circuit 35 opens the relay switch 34 (step S14). Thereby, when the voltage of any one cell reaches the upper limit voltage V1 by charging, further charging is immediately stopped.
On the other hand, when the voltage of any cell is less than the upper limit voltage V1 (step S13: NO), the charge / discharge stop circuit 35 determines whether the voltage of any cell 12 is less than the previously stored lower limit voltage V2. Determination is made (step S15). When the voltage of any cell 12 is less than the lower limit voltage V2 (step S15: YES), the charge / discharge stop circuit 35 opens the relay switch 34 (step S16). Accordingly, when the voltage of any one cell reaches the lower limit voltage V2 due to the discharge, the further discharge is immediately stopped.
また、いずれのセル１２の電圧も上限電圧Ｖ１未満で、且つ、下限電圧Ｖ２以上の場合（ステップＳ１３，Ｓ１５のいずれもＮＯ）、充・放電停止回路３５はステップＳ１１の処理に戻る。このため、セル電圧が上限電圧Ｖ１〜下限電圧Ｖ２の間では、リレースイッチ３４が閉成に維持され、充・放電が許容される。
図６は、組電池モジュールを０．５ＣＡで充電・放電したときの各セル１２の電圧曲線を示しており、縦軸を「セル電圧」、横軸を「充放電容量」で示した図である。なお、図６中、充電時の電圧曲線は符号ｆ１を付して示し、放電時の電圧曲線は符号ｆ２を付して示しており、充電・放電時、各セル１２の電圧はほぼ揃っている。
本実施形態では、セル１２が１個でも３．６Ｖ以上であれば充電を停止するため、電圧危険領域を超えて過充電されたセルは無かった。また、セル１２が１個でも２．２Ｖ未満であれば放電を停止するため、過放電されたセル１２も無かった。従って、充電・放電共に全セル１２が電圧安全領域内であった。
When the voltage of any cell 12 is less than the upper limit voltage V1 and equal to or higher than the lower limit voltage V2 (both NO in steps S13 and S15), the charge / discharge stop circuit 35 returns to the process of step S11. For this reason, when the cell voltage is between the upper limit voltage V1 and the lower limit voltage V2, the relay switch 34 is kept closed, and charging / discharging is permitted.
FIG. 6 shows a voltage curve of each cell 12 when the assembled battery module is charged / discharged at 0.5 CA. The vertical axis shows “cell voltage” and the horizontal axis shows “charge / discharge capacity”. is there. In FIG. 6, the voltage curve at the time of charging is indicated by a reference sign f <b> 1, and the voltage curve at the time of discharging is indicated by a reference sign f <b> 2. Yes.
In this embodiment, even if one cell 12 is 3.6 V or more, charging is stopped, so that no cell is overcharged beyond the voltage risk area. In addition, even if one cell 12 is less than 2.2V, the discharge is stopped, so that there is no overdischarged cell 12. Therefore, all the cells 12 were in the voltage safe region for both charging and discharging.
図７は、組電池モジュールを１．０ＣＡで急速充電・放電したときの各セル１２の電圧曲線を示しており、縦軸を「セル電圧」、横軸を「充放電容量」で示した図である。なお、図７に示す急速充電・放電時も、図６と同様に各セル１２の電圧はほぼ揃っている。
この場合も、セル１２が１個でも３．６Ｖ以上であれば充電を停止するため、電圧危険領域を超えて過充電されたセル１２は無かった。また、セル１２が１個でも２．２Ｖ未満であれば放電を停止するため、過放電されたセルも無かった。急速充電・放電の場合も充電・放電共に全セル１２が電圧安全領域内であった、また、充放電容量も０．５ＣＡ充放電と同等の容量が得られた。この組電池モジュール１１を実施例１の組電池モジュールと言う。
ここで、実施例１の組電池モジュール１１では、各セル１２の性能のばらつきが予め定めた基準範囲内に収まるように各セル１２が選定されている。この性能の選定によって、充電時のセル電圧のばらつきを抑えるようにしている。
FIG. 7 shows a voltage curve of each cell 12 when the assembled battery module is rapidly charged / discharged at 1.0 CA. The vertical axis indicates “cell voltage” and the horizontal axis indicates “charge / discharge capacity”. It is. Note that the voltages of the cells 12 are substantially the same as in FIG. 6 also during the rapid charge / discharge shown in FIG.
In this case as well, even if one cell 12 is 3.6 V or more, charging is stopped, so that no cell 12 is overcharged beyond the voltage risk area. In addition, even if one cell 12 is less than 2.2 V, the discharge is stopped, so that no overdischarged cell is present. In the case of rapid charging / discharging, all the cells 12 were in the voltage safe region for both charging / discharging, and the charge / discharge capacity was equivalent to 0.5CA charge / discharge. This assembled battery module 11 is referred to as an assembled battery module of Example 1.
Here, in the assembled battery module 11 of Example 1, each cell 12 is selected so that the variation in performance of each cell 12 falls within a predetermined reference range. By selecting this performance, variations in cell voltage during charging are suppressed.
［比較例１］
実施例１と同様にして、定格電圧３．２Ｖ、定格容量２０Ａｈのラミネートセルを作製した後、このラミネートセルを８個直列に接続し、実施例１と同様の２４Ｖ系の組電池モジュールを作製した。
そして、この組電池モジュールを、充・放電装置２１を定電流定電圧方式を用いて充・放電を行ない、充電時には充電バランス回路を使用せずに充電した。なお、充・放電は、２８．８Ｖまで定電流で充電し、２８．８Ｖに達したら定電圧充電を行った。
図８は、この比較例１の組電池モジュールを１．０ＣＡの定電流定電圧充電方式で急速充電したときの各セル１２の電圧曲線を示しており、縦軸を「セル電圧」、横軸を「充電時間」で示した図である。この図に示すように、定電流充電領域では各セルの電圧にばらつきは殆どないが、定電圧充電領域では各セルの電圧ばらつきが多くなっている。各セル１２の電圧ばらつきが多いため、電圧危険領域を超えて過充電されるセル１２が生じるおそれがある。
[Comparative Example 1]
In the same manner as in Example 1, a laminate cell having a rated voltage of 3.2 V and a rated capacity of 20 Ah was prepared, and then eight of these laminate cells were connected in series to produce a 24V battery module similar to that in Example 1. did.
Then, this assembled battery module was charged / discharged by using the constant current / constant voltage method for the charging / discharging device 21 and was charged without using the charging balance circuit at the time of charging. In addition, charging / discharging charged with constant current to 28.8V, and performed constant voltage charge, when it reached 28.8V.
FIG. 8 shows a voltage curve of each cell 12 when the assembled battery module of Comparative Example 1 is rapidly charged by a constant current / constant voltage charging method of 1.0 CA, where the vertical axis indicates “cell voltage” and the horizontal axis. Is a diagram showing “charging time”. As shown in this figure, there is almost no variation in the voltage of each cell in the constant current charging region, but there is a large variation in the voltage of each cell in the constant voltage charging region. Since there are many voltage variations of each cell 12, there exists a possibility that the cell 12 overcharged exceeding a voltage danger area may arise.
本実施形態の実施例１及び比較例１の各セル１２は、性能のばらつきが予め定めた基準範囲内に収まるように選定したものであるが、定電流充電領域内のセル電圧のばらつきが小さく、図８では視認することは困難である。一方、定電圧充電領域で生じるセル電圧のばらつきは、図８では３．５Ｖ〜３．８Ｖ程度まであり、十分に視認できる程に大きい。つまり、性能のばらつきを抑えても、定電圧充電領域のセル電圧のばらつきが大きいことが明らかであり、定電圧充電領域で過充電が生じるおそれがある。
本実施例では、各セル１２の性能のばらつきが予め定めた基準範囲内に収まるように選定したが、各セル１２を無作為に抽出した場合にも同様の結果が得られ、定電圧定電流方式にて充電を行なった場合は、更に電圧のばらつきが大きなものであった。
Each cell 12 of Example 1 and Comparative Example 1 of this embodiment is selected so that the variation in performance falls within a predetermined reference range, but the variation in cell voltage in the constant current charging region is small. In FIG. 8, it is difficult to visually recognize. On the other hand, the variation in the cell voltage occurring in the constant voltage charging region is about 3.5V to 3.8V in FIG. That is, even if the performance variation is suppressed, it is clear that the cell voltage variation in the constant voltage charging region is large, and overcharge may occur in the constant voltage charging region.
In this embodiment, the variation in the performance of each cell 12 is selected so as to be within a predetermined reference range. However, the same result is obtained when each cell 12 is randomly extracted. When charging was performed by the method, the voltage variation was further large.
［比較例２］
正極活物質にコバルト酸リチウムを用い、導電剤にアセチレンブラック粉状品を用い、バインダーとしてＰＶＤＦを用い、ディスパー付プラネタリーミキサーで攪拌混合してペーストを調整し、正極１４の基材となる厚み２０μｍのアルミニウム箔に塗布し、乾燥後にプレスして正極１４に用いる正極板を作製した。
正極板以外は、実施例１と同様にして定格電圧３．６Ｖ、定格容量２０Ａｈのラミネートセルを作製した後、このラミネートセルを７個直列に接続し、実施例１と同様の２４Ｖ系の組電池モジュールを作製した。
この組電池モジュールのセルの上限電圧Ｖ１を４．２Ｖ、下限電圧Ｖ２を２．８Ｖとし、実施例１と同様に、組電池モジュールを０．５ＣＡ、１．０ＣＡの定電流定電圧で充電した。つまり、各セルの電圧が全て４．２Ｖ未満であれば充電を継続し、いずれか１セルの電圧が４．２Ｖ以上であれば、リレースイッチ３４を開放して充電を停止した。また、組電池モジュールが放電し、各セルの電圧が全て２．８Ｖ以上であれば放電を継続し、いずれか１セルの電圧が２．８Ｖ未満であれば、リレースイッチ３４を開放して放電を停止した。
[Comparative Example 2]
Lithium cobaltate is used as the positive electrode active material, acetylene black powder is used as the conductive agent, PVDF is used as the binder, the paste is prepared by stirring and mixing with a planetary mixer with a disper, and the thickness becomes the base material of the positive electrode 14 The positive electrode plate used for the positive electrode 14 was produced by applying the aluminum foil of 20 μm and pressing it after drying.
Except for the positive electrode plate, a laminate cell having a rated voltage of 3.6 V and a rated capacity of 20 Ah was prepared in the same manner as in Example 1, and then seven of these laminate cells were connected in series. A battery module was produced.
The upper limit voltage V1 of the battery of this assembled battery module was 4.2V, the lower limit voltage V2 was 2.8V, and the assembled battery module was charged with constant current and constant voltage of 0.5CA and 1.0CA in the same manner as in Example 1. . That is, if all the voltages of each cell were less than 4.2V, charging was continued, and if the voltage of any one cell was 4.2V or more, the relay switch 34 was opened and charging was stopped. If the assembled battery module is discharged and the voltage of each cell is 2.8V or more, the discharge is continued. If the voltage of any one cell is less than 2.8V, the relay switch 34 is opened and discharged. Stopped.
［比較例３］
比較例２と同様にして定格電圧３.６Ｖ、定格容量２０Ａｈのラミネートセルを作製した後、このラミネートセルを７個直列に接続し、比較例２と同様の２４Ｖ系の組電池モジュールを作製した。
この組電池モジュールを充・放電装置２１を定電流定電圧方式を用いて充・放電を行ない、充電時には充電バランス回路を使用し充電した。なお、充・放電は、電圧が２８．８Ｖまでは定電流で充電し、２８．８Ｖに達したら定電圧充電を行った。
[Comparative Example 3]
A laminate cell having a rated voltage of 3.6 V and a rated capacity of 20 Ah was produced in the same manner as in Comparative Example 2, and then seven of these laminate cells were connected in series to produce a 24V battery module similar to that in Comparative Example 2. .
This assembled battery module was charged / discharged by using the charge / discharge device 21 using a constant current / constant voltage method, and charged using a charge balance circuit. In addition, charging / discharging charged with the constant current until the voltage was 28.8V, and performed the constant voltage charge when it reached 28.8V.
［比較例４］
正極活物質にマンガン酸リチウムを用い、導電剤にアセチレンブラック粉状品を用い、バインダーとしてＰＶＤＦを用い、ディスパー付プラネタリーミキサーで攪拌混合してペーストを調整し、正極１４の基材となる厚み２０μｍのアルミニウム箔に塗布し、乾燥後にプレスして正極１４に用いる正極板を作製した。
正極板以外は、実施例１と同様にして定格電圧３．６Ｖ、定格容量２０Ａｈのラミネートセルを作製した後、このラミネートセルを７個直列に接続し、実施例１と同様の２４Ｖ系の組電池モジュールを作製した。
この組電池モジュールのセルの上限電圧Ｖ１を４．２Ｖ、下限電圧Ｖ２を２．８Ｖとし、実施例１と同様に、組電池モジュールを０．５ＣＡの定電流で充電した。つまり、各セルの電圧が全て４．２Ｖ未満であれば充電を継続し、いずれか１セルの電圧が４．２Ｖ以上であれば充電を停止した。また、組電池モジュールが放電し、各セルの電圧が全て２．８Ｖ以上であれば放電を継続し、いずれか１セルの電圧が２．８Ｖ未満であれば放電を停止した。
[Comparative Example 4]
Lithium manganate is used as the positive electrode active material, acetylene black powder is used as the conductive agent, PVDF is used as the binder, the paste is prepared by stirring and mixing with a planetary mixer with a disperser, and the thickness used as the base material of the positive electrode 14 The positive electrode plate used for the positive electrode 14 was produced by applying the aluminum foil of 20 μm and pressing it after drying.
Except for the positive electrode plate, a laminate cell having a rated voltage of 3.6 V and a rated capacity of 20 Ah was prepared in the same manner as in Example 1, and then seven of these laminate cells were connected in series. A battery module was produced.
The upper limit voltage V1 of the battery of this assembled battery module was 4.2V, the lower limit voltage V2 was 2.8V, and the assembled battery module was charged with a constant current of 0.5 CA in the same manner as in Example 1. That is, charging was continued if the voltage of each cell was less than 4.2V, and charging was stopped if the voltage of any one cell was 4.2V or higher. Moreover, discharge was continued if the assembled battery module was discharged and all the voltages of each cell were 2.8V or more, and discharge was stopped if the voltage of any one cell was less than 2.8V.
［試験１］
上記各組電池モジュールを、１．０ＣＡで急速充電・放電を繰り返した。このときのサイクル寿命特性を図９に示す。なお、図９において縦軸を「放電容量／定格容量」、横軸を「サイクル寿命」で示した。
図９に示すように、実施例１の組電池モジュールが最も放電容量の低下が少なく、次に比較例１，２，４の順で放電容量の低下が少なかった。
具体的には、実施例１の組電池モジュール１１は、約１０００サイクルの充電・放電を行うと、「放電容量／定格容量」が約１０８％から約９６％へと低下した。一方、比較例１の組電池モジュールは、約１０００サイクルの充電・放電を行うと、約１１３％から約６４％へと大きく低下した。また、比較例２の組電池モジュールは、約７００サイクルで約７５％から約３０％へと大幅に低下し、比較例４の組電池モジュールは、６００サイクルに満たないうちに約７７％から約２０％まで大幅に低下した。
比較例１、２、４において性能が低下したのは、比較例１では、定電圧充電領域で過充電になったセルの劣化が進んだもの考えられ、比較例２〜３では、充電・放電サイクルを繰り返す毎にセルの内部抵抗が上昇し、１．０ＣＡでの充電分極が大きくなり、定電流充電で充電され難くなったと考えられる。これらのことから、実施例１の組電池モジュール１１が、比較例１、２、４と比べて非常に良好なサイクル寿命特性であることが判る。
[Test 1]
Each of the assembled battery modules was repeatedly rapidly charged and discharged at 1.0 CA. The cycle life characteristics at this time are shown in FIG. In FIG. 9, the vertical axis represents “discharge capacity / rated capacity” and the horizontal axis represents “cycle life”.
As shown in FIG. 9, the assembled battery module of Example 1 had the least decrease in discharge capacity, and then the decrease in discharge capacity in the order of Comparative Examples 1, 2, and 4 was small.
Specifically, when the assembled battery module 11 of Example 1 was charged and discharged for about 1000 cycles, the “discharge capacity / rated capacity” decreased from about 108% to about 96%. On the other hand, the assembled battery module of Comparative Example 1 greatly decreased from about 113% to about 64% when charged and discharged for about 1000 cycles. In addition, the assembled battery module of Comparative Example 2 is significantly reduced from about 75% to about 30% in about 700 cycles, and the assembled battery module of Comparative Example 4 is about 77% to about 30% before reaching 600 cycles. It decreased significantly to 20%.
In Comparative Examples 1, 2, and 4, the performance decreased because in Comparative Example 1, the cell overcharged in the constant voltage charging region was considered to have deteriorated. In Comparative Examples 2-3, charging and discharging were considered. Each time the cycle is repeated, the internal resistance of the cell increases, the charge polarization at 1.0 CA increases, and it is considered that it is difficult to charge by constant current charging. From these things, it turns out that the assembled battery module 11 of Example 1 has very good cycle life characteristics as compared with Comparative Examples 1, 2, and 4.
［試験２］
図１０は、比較例２の組電池モジュールを０．５ＣＡの定電流定電圧充電方式と１．０ＣＡの定電流定電圧充電方式とで充電した場合の特性を示す。図１０は縦軸の主軸を「電圧」、及び第２軸を「充電電流／充電容量」、即ち満充電時を１．０とした時の容量比、横軸を「充電時間」で示した図である。
ここで、図１０は、０．５ＣＡの定電流定電圧充電方式で充電した場合の電圧ＶＣ、「充電電流／充電容量」ＪＣ、電流ＩＣ、及び、１．０ＣＡの定電流定電圧充電方式で充電した場合の電圧ＶＤ、「充電電流／充電容量」ＪＤ、電流ＩＤを示している。
また、タイミングＴＣは、０．５ＣＡの定電流定電圧充電方式で、定電流充電から定電圧充電に切り替わるタイミングであり、タイミングＴＤは、１．０ＣＡの定電流定電圧充電方式で、定電流充電から定電圧充電に切り替わるタイミングである。
図１０に示すように、タイミングＴＣ，ＴＤで定電流充電から定電圧充電に切り替わると、充電容量ＪＣ，ＪＤの傾きが各々緩やかになるので、傾きが緩やかになる分だけ充電時間が長くなる。
これに対し、実施例１では、定電流充電のみで充電するため、図１０に示すような「充電容量の傾きが緩やかになる変化」がなく、充電時間を短くできると考えられる。
[Test 2]
FIG. 10 shows characteristics when the assembled battery module of Comparative Example 2 is charged by a constant current constant voltage charging method of 0.5 CA and a constant current constant voltage charging method of 1.0 CA. FIG. 10 shows the main axis of the vertical axis as “voltage”, the second axis as “charge current / charge capacity”, that is, the capacity ratio when the full charge is 1.0, and the horizontal axis as “charge time”. FIG.
Here, FIG. 10 shows a voltage VC, a “charging current / charge capacity” JC, a current IC, and a constant current constant voltage charging method of 1.0 CA when charging is performed with a constant current constant voltage charging method of 0.5 CA. The voltage VD, “charging current / charging capacity” JD, and current ID when charging are shown.
Timing TC is a timing for switching from constant current charging to constant voltage charging in a constant current constant voltage charging method of 0.5 CA, and timing TD is a constant current charging in constant current constant voltage charging method of 1.0 CA. This is the timing when switching from constant voltage charging to constant voltage charging.
As shown in FIG. 10, when switching from constant current charging to constant voltage charging at timings TC and TD, the slopes of the charging capacities JC and JD become gentle, so that the charging time becomes longer by the amount of the gentle slope.
On the other hand, in Example 1, since charging is performed only with constant current charging, there is no “change in which the slope of the charging capacity becomes gentle” as shown in FIG. 10, and the charging time can be shortened.
これを検証すべく、各組電池モジュールを充電して３０分休止後、１．０ＣＡで表１に示す各下限値まで定電流放電を行った。その結果を表１に示す。なお、表１には、各実施例及び比較例の充電電流、充電方法、充電時間、下限電圧値、も合わせて示している、初期容量を併記した。 In order to verify this, each assembled battery module was charged and rested for 30 minutes, and then a constant current discharge was performed to each lower limit value shown in Table 1 at 1.0 CA. The results are shown in Table 1. In Table 1, the initial capacity, which also shows the charging current, the charging method, the charging time, and the lower limit voltage value of each example and comparative example, is shown together.
表１に示すように、定格容量の１００％以上の初期容量を得られたのは、実施例１、比較例１及び比較例３の組電池モジュールであり、比較例２及び比較例４の組電池モジュールでは１００％以上の放電容量を得ることができなかった。
また、１００％以上の放電容量を得られた組電池モジュールのうち、実施例１の組電池モジュール１１が、他の比較例と比べて短時間で充電することが可能であった。
このことから、実施例１の組電池モジュール１１が、比較例１〜４と比べて高い初期容量と短い充電時間とを高バランスで両立できることが判った。
As shown in Table 1, it was the assembled battery module of Example 1, Comparative Example 1 and Comparative Example 3 that obtained an initial capacity of 100% or more of the rated capacity, and the combination of Comparative Example 2 and Comparative Example 4 In the battery module, a discharge capacity of 100% or more could not be obtained.
Moreover, the assembled battery module 11 of Example 1 was able to charge in a short time compared with another comparative example among the assembled battery modules which obtained 100% or more of discharge capacity.
From this, it was found that the assembled battery module 11 of Example 1 can achieve both a high initial capacity and a short charging time with a high balance as compared with Comparative Examples 1 to 4.
以上のような裏付けにより、本実施形態の組電池モジュール１１は、充電バランス回路を必要とせずに良好なサイクル寿命で充電／放電でき、且つ、高い放電容量を得ながら充電時間を短縮できる。このため、従来の非水系二次電池と比べて、部品点数を低減することができ、簡易な構成で、過充電／過放電を回避して充電／放電でき、充電時間も短縮できる。
しかも、本実施形態では、定電流充電だけで充電するため、定電流定電圧充電方式の充電装置と比べて、充・放電装置２１の部品点数を低減して簡易な構成にすることができる。従って、本実施形態では、組電池モジュール１１や充・放電装置２１からなる電源システム１０を安価に提供することが可能になる。
また、急速充電・放電を行っても、殆ど使用できる容量が変わらず、利便性の良い電源システム１０を提供することが可能である。
With the above support, the assembled battery module 11 of the present embodiment can be charged / discharged with a good cycle life without requiring a charge balance circuit, and the charging time can be shortened while obtaining a high discharge capacity. For this reason, compared with the conventional non-aqueous secondary battery, the number of parts can be reduced, and with a simple configuration, overcharge / overdischarge can be avoided and charged / discharged, and the charging time can be shortened.
In addition, in the present embodiment, charging is performed only by constant current charging, and therefore, the number of parts of the charging / discharging device 21 can be reduced and the configuration can be simplified as compared with the charging device of the constant current constant voltage charging method. Therefore, in this embodiment, it becomes possible to provide the power supply system 10 including the assembled battery module 11 and the charge / discharge device 21 at low cost.
In addition, even when rapid charging / discharging is performed, the usable capacity hardly changes, and it is possible to provide a convenient power supply system 10.
また、本実施形態では、図３に示すように、組電池１３は、一定の電流で充電した場合に、満充電の９０％以上となる充電末期で、充電末期以前よりも電池電圧が急上昇するため、充電停止電圧である上限電圧Ｖ１は、所定の電圧値、即ち、充電末期内の電圧値（３．６Ｖ）に設定することで、過充電を確実に回避しつつ、ほぼ満充電の状態で充電停止させることができる。
また、本実施形態では、定電流充電だけで充電する構成で、各セル１２の性能のばらつきを予め定めた基準範囲内に抑えることが可能であり、充電時のセル電圧のばらつきを簡易かつ確実に抑えることができる。仮に、定電流定電圧方式で充電する場合に充電時のセル電圧のばらつきを精度良く抑えようとすると、充電バランス回路が必要となり、低価格化が困難である。つまり、本実施形態では、これによっても低価格化と過充電防止とを両立することができる。
In the present embodiment, as shown in FIG. 3, when the battery pack 13 is charged with a constant current, the battery voltage rises more rapidly than before the end of charge at the end of charge, which is 90% or more of full charge. Therefore, the upper limit voltage V1, which is the charge stop voltage, is set to a predetermined voltage value, that is, a voltage value within the end of charging (3.6V), so that overcharge is reliably avoided and almost fully charged. Can be used to stop charging.
Further, in the present embodiment, with the configuration in which charging is performed only with constant current charging, it is possible to suppress the variation in performance of each cell 12 within a predetermined reference range, and the variation in cell voltage during charging can be easily and reliably performed. Can be suppressed. If charging is performed with a constant current / constant voltage method in an attempt to accurately suppress variations in cell voltage during charging, a charge balance circuit is required, making it difficult to reduce the price. That is, in the present embodiment, it is possible to achieve both cost reduction and overcharge prevention.
ここで、図１１は、本実施形態の組電池モジュール１１を使用して作製した電池駆動機器５１を示している。この電池駆動機器５１は、ＤＣ−ＡＣインバータと組み合わせてＡＣ１００Ｖのポータブル電源システムを構成する装置であり、ハンドル５２Ａを有する筐体５２と、筐体５２に設けられた電源スイッチ５３と、任意の電力消費機器を接続する接続口となるコンセント部５４とを有している。 Here, FIG. 11 shows a battery drive device 51 manufactured using the assembled battery module 11 of the present embodiment. The battery-powered device 51 is a device that constitutes an AC 100V portable power system in combination with a DC-AC inverter, and includes a housing 52 having a handle 52A, a power switch 53 provided in the housing 52, and arbitrary power. It has the outlet part 54 used as the connection port which connects a consumer device.
上述した実施形態は、あくまでも本発明の一態様を示すものであり、本発明の主旨を逸脱しない範囲で任意に変形及び応用が可能である。例えば、上記実施形態では、正極に用いるオリビン構造のリチウム遷移金属複合酸化物として、リン酸鉄リチウムを使用する場合を説明したが、これに限らず、リン酸マンガンリチウム（ＬｉＭｎＰＯ４）等でも良い。
また、上記実施形態では、ポータブル電源システムを例に説明したが、これに限らず、電気自動車、ハイブリッド車両、鉄道車両等の移動体用電源、非常用電源等のバックアップ用電源、太陽光発電や風力発電等の負荷平準化用電源等にも適用できる。
The above-described embodiment is merely an aspect of the present invention, and can be arbitrarily modified and applied without departing from the gist of the present invention. For example, in the embodiment described above, the case where lithium iron phosphate is used as the lithium transition metal composite oxide having an olivine structure used for the positive electrode is not limited thereto, but may be lithium manganese phosphate (LiMnPO 4 ) or the like. .
In the above-described embodiment, the portable power supply system has been described as an example. However, the present invention is not limited to this, and power sources for moving bodies such as electric vehicles, hybrid vehicles, and railway vehicles, backup power sources such as emergency power sources, solar power generation, It can also be applied to load leveling power sources such as wind power generation.
１０ 電源システム
１１ 組電池モジュール
１２ セル（単電池）
１３ 組電池
１４ 正極
１５ 負極
２１ 充・放電装置
３１ 充・放電制御装置（制御装置）
３３ 電圧計
３４ リレースイッチ（遮断部材）
３５ 充・放電停止回路
Ｖ１ 上限電圧（充電停止電圧）
Ｖ２ 下限電圧
10 power supply system 11 battery module 12 cell (single cell)
13 assembled battery 14 positive electrode 15 negative electrode 21 charge / discharge device 31 charge / discharge control device (control device)
33 Voltmeter 34 Relay switch (blocking member)
35 Charge / discharge stop circuit V1 Upper limit voltage (charge stop voltage)
V2 lower limit voltage
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| JP5911897B2 (en) * | 2014-01-30 | 2016-04-27 | 古河電気工業株式会社 | Secondary battery charge control device and secondary battery charge control method |
| JP2016092877A (en) * | 2014-10-30 | 2016-05-23 | 株式会社カネカ | Power storage system containing battery pack |
| EP3258527A4 (en) * | 2015-02-10 | 2018-08-22 | Kaneka Corporation | Power storage device |
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| JP2000333381A (en) * | 1999-03-15 | 2000-11-30 | Japan Storage Battery Co Ltd | Charging method and charger |
| JP2003157908A (en) * | 2001-09-10 | 2003-05-30 | Ntt Power & Building Facilities Inc | Charging device for lithium ion secondary cell, and charging method of the same |
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