JP2002050407A - Nonaqueous electrolyte secondary cell and control method of charge and discharge - Google Patents
Nonaqueous electrolyte secondary cell and control method of charge and dischargeInfo
- Publication number
- JP2002050407A JP2002050407A JP2000234449A JP2000234449A JP2002050407A JP 2002050407 A JP2002050407 A JP 2002050407A JP 2000234449 A JP2000234449 A JP 2000234449A JP 2000234449 A JP2000234449 A JP 2000234449A JP 2002050407 A JP2002050407 A JP 2002050407A
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- Japan
- Prior art keywords
- charge
- electrode plate
- negative electrode
- positive electrode
- electrode
- Prior art date
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Classifications
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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
- 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
-
- 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
- Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
- Y02P70/00—Climate change mitigation technologies in the production process for final industrial or consumer products
- Y02P70/50—Manufacturing or production processes characterised by the final manufactured product
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- Connection Of Batteries Or Terminals (AREA)
Abstract
Description
【0001】[0001]
【発明の属する技術分野】本発明は、非水電解質二次電
池の充放電制御方法に関するものである。BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charge / discharge control method for a non-aqueous electrolyte secondary battery.
【0002】[0002]
【従来の技術】近年、移動体通信機器、携帯電子機器の
主電源として利用されているリチウム二次電池は、起電
力が高く、高エネルギー密度である特長を有している。
負極材料としてリチウム金属を用いたリチウム二次電池
は、エネルギー密度は高いが、充電時に負極にデンドラ
イトが析出し、充放電を繰り返すことによりセパレータ
を突き破って正極側に達し、内部短絡を起こす恐れがあ
った。また、析出したデンドライトは比表面積が大きい
ため反応活性度が高く、その表面で電解液中の溶媒と反
応して電子伝導性に欠いた固体電解質的な界面皮膜を形
成する。そのため電池の内部抵抗が高くなったり、電子
伝導のネットワークから孤立した粒子が存在するように
なり、これらが充放電効率を低下させる要因となってい
る。これらの理由で負極材料としてリチウム金属を用い
たリチウム二次電池は、低い信頼性、および短いサイク
ル寿命に問題があった。2. Description of the Related Art In recent years, lithium secondary batteries used as main power sources for mobile communication devices and portable electronic devices have the characteristics of high electromotive force and high energy density.
A lithium secondary battery using lithium metal as the negative electrode material has a high energy density, but dendrites are deposited on the negative electrode during charging, and may repeatedly break through the separator to reach the positive electrode side by repeated charging and discharging, causing an internal short circuit. there were. Further, the precipitated dendrite has a high specific activity because of its large specific surface area, and reacts with the solvent in the electrolytic solution on its surface to form a solid electrolyte interface film lacking electron conductivity. For this reason, the internal resistance of the battery is increased, and particles isolated from the electron conduction network are present, and these are factors that lower the charge / discharge efficiency. For these reasons, lithium secondary batteries using lithium metal as the negative electrode material have problems with low reliability and short cycle life.
【0003】現在、リチウム金属に替わる負極材料とし
て、リチウムイオンを吸蔵・放出できる炭素材料を使用
し実用化に至っている。通常、炭素材料負極で金属リチ
ウムは析出しないため、デンドライトによる内部短絡の
問題はない。At present, a carbon material capable of occluding and releasing lithium ions is used as a negative electrode material instead of lithium metal, and has been put to practical use. Normally, metallic lithium does not precipitate at the carbon material negative electrode, so there is no problem of internal short circuit due to dendrite.
【0004】このようなリチウム二次電池の充電は、一
定電流で充電し電池が設定電圧に達した後、設定電圧以
上にならないように充電電流を減少して電圧を一定に保
つ充電方法(以下、CVCC充電と称す。)を用いてい
る。これは次のような理由からである。ニカド電池やニ
ッケル水素電池の充電では、満充電状態に近づくと充電
状態の高い部分で電流が副反応に費やされ充電状態の低
い部分との充電の不均一を解消する。しかし、副反応が
ほとんど生じないリチウム二次電池では、充電時に設定
電圧に到達後に電流値を減少させるCVCC充電を用い
て極板内で生じる充電の不均一を解消している。すなわ
ち、CVCC充電は、電極上で活物質の充電が不均一に
なるのを防ぐという役割を担っている。尚、ここでいう
充電の不均一とは、電極内部に生じた電流分布により同
一極板内で電位の異なる箇所が生じることを示し、これ
により同一極板内で充電状態の異なる活物質が存在する
状態を指す。[0004] Such a lithium secondary battery is charged with a constant current, and after the battery reaches a set voltage, the charge current is reduced so as not to exceed the set voltage to keep the voltage constant (hereinafter referred to as a charge method). , CVCC charging). This is for the following reasons. In the charging of a nickel-cadmium battery or a nickel-metal hydride battery, when approaching a fully charged state, current is spent on a side reaction in a high charged state, thereby eliminating uneven charging in a low charged state. However, in a lithium secondary battery in which side reactions hardly occur, non-uniform charging in the electrode plate is eliminated by using CVCC charging in which the current value is reduced after reaching a set voltage during charging. That is, CVCC charging has a role of preventing non-uniform charging of the active material on the electrode. Here, the non-uniform charge means that a portion having a different potential is generated in the same electrode plate due to a current distribution generated inside the electrode, whereby active materials having different charge states exist in the same electrode plate. Refers to the state in which
【0005】また、リチウム二次電池は有機電解液を使
用しているためイオンの伝導率が低く電極内部での充放
電の不均一を生じやすい。そのため水溶液系の電解液を
持つニカド電池やニッケル水素電池に比べ極板面積を広
くし、電極の厚みを薄くすることで活物質の反応性を高
め、電極内部での充放電の不均一を解消している。[0005] Further, since the lithium secondary battery uses an organic electrolyte, the ion conductivity is low and the charge and discharge in the electrode are likely to be uneven. Therefore, compared to nickel-cadmium batteries and nickel-metal hydride batteries that have an aqueous electrolyte solution, the electrode area is increased and the thickness of the electrodes is reduced to increase the reactivity of the active material and eliminate uneven charging and discharging inside the electrodes. are doing.
【0006】しかしながら、上記のように極板面積を広
くし、CVCC充電を用いても、充電の不均一の解消は
まだ完全とはいえない。[0006] However, even if the electrode plate area is widened and CVCC charging is used as described above, the elimination of non-uniform charging is not yet complete.
【0007】まず、電池内部の極板面積が大きいことか
ら次のような課題が生ずる。通常、リチウム二次電池で
は一対の正極と負極の端子を有し、この端子から得られ
る電圧を制御することにより充放電を行っている。しか
し、この端子は電極上に存在する様々な電位の代表電位
を示しているにすぎず、電極内で生じている電位の不均
一さは不明である。この電位の不均一は、電池内部の極
板面積が広くなるほど大きくなり家庭用小型電力貯蔵装
置、モーターを動力源とする自動二輪車、電気自動車、
ハイブリット電気自動車等に用いられる大型電池におい
て重要な課題となる。すなわち極板内に生じた電位の分
布は、極板内で充電が不均一に生じ充電や放電が過剰に
行われている箇所と充電や放電が不十分な箇所が同一極
板内に生じることになる。過剰に充電が行われた場合、
負極材料に吸蔵されるリチウムイオンが負極表面にリチ
ウム金属として析出することになる。この析出したリチ
ウム金属の充放電効率は非常に低いために電池のサイク
ル寿命を著しく低下する結果になる。また正極において
は、正極の結晶内に存在するリチウムが過剰に放出され
る。この結果、正極の結晶が不安定となり電池のサイク
ル寿命を著しく低下する結果になる。First, the following problems arise because the area of the electrode plate inside the battery is large. Usually, a lithium secondary battery has a pair of positive and negative terminals, and charges and discharges by controlling the voltage obtained from these terminals. However, this terminal merely indicates a representative potential of various potentials existing on the electrode, and the nonuniformity of the potential generated in the electrode is unknown. The non-uniformity of the electric potential increases as the area of the electrode plate inside the battery increases, and the power storage device for home use, a motorcycle powered by a motor, an electric vehicle,
This is an important issue for large batteries used in hybrid electric vehicles and the like. In other words, the distribution of the potential generated in the electrode plate is that charging is unevenly performed in the electrode plate and a portion where charging or discharging is excessively performed and a portion where charging or discharging is insufficient occur in the same electrode plate. become. If overcharged,
Lithium ions occluded in the negative electrode material are deposited on the negative electrode surface as lithium metal. Since the charge and discharge efficiency of the deposited lithium metal is very low, the cycle life of the battery is significantly reduced. In the positive electrode, lithium present in the crystal of the positive electrode is excessively released. As a result, the crystals of the positive electrode become unstable and the cycle life of the battery is significantly reduced.
【0008】次に、充放電のサイクルの繰り返しに伴い
電池が劣化した場合における従来のCVCC充電につい
ての課題を説明する。リチウムイオン電池のようにリチ
ウムイオンが正負極を行き来することで電池が成立して
いる電池系においては、正負極のリチウム吸蔵・放出容
量(以降、容量と略す。)のバランスを考慮する必要が
ある。例えば、正極容量が負極容量に比べ大きい場合、
電池を充電した場合は正極から放出されたリチウムイオ
ンは負極に全部吸蔵されないために負極表面にリチウム
金属として析出することになる。この析出したリチウム
金属の充放電効率は非常に低いために、電池のサイクル
寿命を著しく低下する結果になる。Next, a description will be given of a problem of the conventional CVCC charging when the battery is deteriorated due to the repetition of the charge / discharge cycle. In a battery system, such as a lithium ion battery, in which a battery is formed by lithium ions moving between the positive and negative electrodes, it is necessary to consider the balance of the lithium storage / release capacity (hereinafter abbreviated as capacity) of the positive and negative electrodes. is there. For example, when the positive electrode capacity is larger than the negative electrode capacity,
When the battery is charged, the lithium ions released from the positive electrode are not entirely occluded by the negative electrode, and are deposited on the negative electrode surface as lithium metal. Since the charge and discharge efficiency of the deposited lithium metal is very low, the cycle life of the battery is significantly reduced.
【0009】一方、負極容量が正極容量より著しく大き
い場合は、正極の結晶内に存在するリチウムが過剰に放
出される。この結果、正極の結晶が不安定となり電池の
サイクル寿命を著しく低下することになる。このような
課題を解決するために特開平5−62712号公報で正
極容量と負極容量の容量バランスの最適値を規定するこ
とが提案されている。On the other hand, when the capacity of the negative electrode is significantly larger than the capacity of the positive electrode, lithium present in the crystal of the positive electrode is excessively released. As a result, the crystals of the positive electrode become unstable, and the cycle life of the battery is significantly reduced. In order to solve such a problem, Japanese Patent Application Laid-Open No. 5-62712 proposes to specify an optimum value of a capacity balance between a positive electrode capacity and a negative electrode capacity.
【0010】しかし、電池を作成した初期の段階におい
て正極と負極の容量バランスが最適に設計されていて
も、充放電のサイクルを経過することで電池が劣化する
とともに正極と負極の容量バランスが崩れてくる。この
場合、正極が早く劣化した場合でも、負極が早く劣化し
た場合でも、一方の容量が著しく他方の容量より大きく
なるため、劣化した側の極板に過剰な負担がかかり、サ
イクル寿命が加速度的に短くなるという問題点もある。However, even when the capacity balance between the positive electrode and the negative electrode is designed optimally at the initial stage of the production of the battery, the battery deteriorates and the capacity balance between the positive electrode and the negative electrode is lost due to the lapse of charge / discharge cycles. Come. In this case, even if the positive electrode deteriorates quickly or the negative electrode deteriorates quickly, one of the capacities becomes significantly larger than the other, so that an excessive load is applied to the deteriorated electrode plate, and the cycle life is accelerated. There is also a problem that it becomes shorter.
【0011】[0011]
【発明が解決しようとする課題】本発明は、このような
従来の課題を解決するものであり、極板面積が大きい場
合、また充放電サイクルの繰り返しに伴い電池が劣化し
た場合においても充放電を最適に行うことで電極上に生
じる不均一な充電状態を解消し、充放電効率とサイクル
特性を向上させるリチウム二次電池の充放電制御方法を
提供することを目的とする。SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned conventional problems, and is intended to be used even when the electrode area is large or when the battery is deteriorated due to repeated charge / discharge cycles. It is an object of the present invention to provide a charge / discharge control method for a lithium secondary battery in which a non-uniform charge state generated on an electrode is eliminated by performing the above-mentioned steps optimally, and charge / discharge efficiency and cycle characteristics are improved.
【0012】[0012]
【課題を解決するための手段】上記課題を解決すべく、
本発明の非水電解質二次電池の充放電制御方法は、正極
もしくは負極の極板が1個以上の電位を確認し得る端子
を有し、各端子から得られる電位を参照して各端子が独
立に充放電を行うものである。すなわち、従来のように
電池の電圧のみで充放電を制御するのではなく、各端子
により極板の電位を直接測定することにより、電極上に
生じる不均一な充電状態を解消するものである。Means for Solving the Problems In order to solve the above problems,
In the method for controlling charge and discharge of a nonaqueous electrolyte secondary battery according to the present invention, the positive or negative electrode plate has one or more terminals capable of confirming a potential, and each terminal is referred to a potential obtained from each terminal. It performs charging and discharging independently. That is, instead of controlling charging / discharging only by the voltage of the battery as in the related art, the non-uniform charging state generated on the electrode is eliminated by directly measuring the potential of the electrode plate by each terminal.
【0013】一対の端子しか有しない従来型の電池で
は、この一対の端子から得られる電圧だけでは、先述し
た極板内に生じた充電状態(電位)の不均一を補正する
には不充分であるのに対し、本発明によれば電位が不均
一となる極板の各所において正極と負極を独立に電位を
測定して充電することができる。また、充放電サイクル
に伴い容量バランスを崩した電池においても同様に電極
の各箇所で独立して電位を測定して、劣化状態に見合っ
た充電をすることができる。In a conventional battery having only a pair of terminals, the voltage obtained from the pair of terminals alone is not sufficient to correct the above-described nonuniform charge state (potential) generated in the electrode plate. On the other hand, according to the present invention, the positive electrode and the negative electrode can be measured and charged independently at various points on the electrode plate where the electric potential becomes non-uniform. Similarly, in a battery in which the capacity balance has been lost due to the charge / discharge cycle, the potential can be measured independently at each part of the electrode, and the battery can be charged in accordance with the deterioration state.
【0014】[0014]
【発明の実施の形態】本発明の非水電解質二次電池は、
リチウムの吸蔵・放出が可能な正極板及び負極板がセパ
レータを介して構成され、リチウム塩を溶媒に溶解した
非水電解液、正極または負極の電極電位を測るための参
照電極を備えている。この正極板上に極板の電位を直接
確認し得る1個以上、好ましくは複数個の端子を有して
いる。1個の場合は、従来の電池で使用されている正極
端子をそのままの形態で本発明の端子とすることができ
る。複数個の場合は、各端子が直接接することのないよ
うに配置する。そして、この端子から得られる極板の電
位を参照して、設置されている各端子が独立に充放電を
行うようにしている。また、極板の電位を直接確認し得
る1個以上、好ましくは複数個の端子は、正極板上では
なく負極板上であってもよい。さらに、正極板および負
極板の両極板上に上記端子を設置してもよい。但し、各
極板に複数個の端子を設置する場合、各極板に流れる電
流の合計が、等しくなるように制御する必要がある。BEST MODE FOR CARRYING OUT THE INVENTION The non-aqueous electrolyte secondary battery of the present invention
A positive electrode plate and a negative electrode plate capable of inserting and extracting lithium are formed via a separator, and include a nonaqueous electrolyte in which a lithium salt is dissolved in a solvent, and a reference electrode for measuring the electrode potential of the positive electrode or the negative electrode. On the positive electrode plate, one or more terminals, preferably a plurality of terminals, for directly checking the potential of the electrode plate are provided. In the case of one, the positive electrode terminal used in the conventional battery can be used as it is as the terminal of the present invention. When there are a plurality of terminals, the terminals are arranged so as not to be in direct contact with each other. Each terminal installed is charged and discharged independently with reference to the potential of the electrode plate obtained from the terminal. One or more, preferably a plurality of terminals capable of directly confirming the potential of the electrode plate may be provided on the negative electrode plate instead of on the positive electrode plate. Further, the terminals may be provided on both the positive and negative electrode plates. However, when a plurality of terminals are provided on each electrode plate, it is necessary to control so that the total current flowing through each electrode plate becomes equal.
【0015】電池電圧を測定するための一対の端子しか
有しない従来型の電池では、正極又は負極の極板内で電
位の不均一が生じた場合、これを制御することはなかっ
た。しかしながら、本発明のように正極板または負極板
もしくはその両方に複数の端子が存在し、正極と負極の
電位の差である電池電圧ではなく、極板の電位を直接測
定し活物質の正確な充電状態を把握することで極板上に
電位の不均一を生じることなく均一な充電を行うことが
できる。すなわち、充電が過剰な領域の端子では充電電
流を絞り、また充電が不充分な領域の端子では電流を継
続して流し続けることにより極板内で生じた充電の不均
一は解消される。In a conventional battery having only a pair of terminals for measuring a battery voltage, when a non-uniform potential occurs in a positive electrode plate or a negative electrode plate, it is not controlled. However, as in the present invention, a plurality of terminals are present on the positive electrode plate and / or the negative electrode plate, and not the battery voltage, which is the difference between the potentials of the positive electrode and the negative electrode, but the direct measurement of the potential of the electrode plate to accurately measure the active material. By grasping the charging state, uniform charging can be performed without causing non-uniform potential on the electrode plate. That is, the charging current is reduced in the terminals in the excessively charged region, and the current is continuously supplied in the terminals in the insufficiently charged region, whereby the uneven charging caused in the electrode plate is eliminated.
【0016】また、従来の技術では一対の正極と負極か
ら得られる電池電圧を元に充電しているため、充放電の
サイクルにより劣化した電池においても初期の設定電圧
まで充電を行っている。しかし、電池の劣化が正極の容
量減少である場合、負極の電位が下がらないうちに正極
は満充電の電位に到達することになる。すなわち、正極
と負極の電位差である電池電圧が設定値まで達していな
いにもかかわらず、正極は満充電状態となる。この状態
の電池を設定電圧まで充電すると正極は過充電状態とな
る。この場合、正極の電位を測定し、正極が設定電位に
到達した後、設定電位以上にならないように充電電流を
減少させる充電方法であれば正極が過充電状態となるこ
とはない。また、逆に電池の劣化が負極の容量減少であ
る場合、負極の能力以上に正極からリチウムが供給さ
れ、負極の表面上にリチウムが析出することになる。こ
の場合は、負極の電位を測定しリチウムが析出する電位
を超えないように充電電流を減少することで負極上にリ
チウム金属が析出することを抑えることができる。In the prior art, since the battery is charged based on the battery voltage obtained from the pair of positive and negative electrodes, even the battery deteriorated by the charge / discharge cycle is charged to the initial set voltage. However, if the deterioration of the battery is a decrease in the capacity of the positive electrode, the positive electrode reaches a fully charged potential before the potential of the negative electrode does not decrease. That is, the positive electrode is fully charged even though the battery voltage, which is the potential difference between the positive electrode and the negative electrode, has not reached the set value. When the battery in this state is charged to the set voltage, the positive electrode becomes overcharged. In this case, if the charging method is such that the potential of the positive electrode is measured, and after the positive electrode reaches the set potential, the charging current is reduced so as not to exceed the set potential, the positive electrode does not become overcharged. On the other hand, when the deterioration of the battery is a decrease in the capacity of the negative electrode, lithium is supplied from the positive electrode beyond the capacity of the negative electrode, and lithium is deposited on the surface of the negative electrode. In this case, the potential of the negative electrode is measured, and the charging current is reduced so as not to exceed the potential at which lithium is deposited, whereby the deposition of lithium metal on the negative electrode can be suppressed.
【0017】前記のように、充電の制御を正極で行うか
負極で行うかは電池のサイクル寿命劣化を生じさせる原
因が正極にあるか負極にあるかによって異なる。従っ
て、その原因がある極に極板の電位を測定する端子が備
わっていればよい。As described above, whether charging is controlled with the positive electrode or with the negative electrode depends on whether the cause of deterioration of the cycle life of the battery is caused by the positive electrode or the negative electrode. Therefore, it is only necessary that the pole having the cause has a terminal for measuring the potential of the electrode plate.
【0018】電池のサイクル寿命劣化を生じさせる原因
が正極にあるか負極にあるかは、正極と負極の単位面積
あたりの充放電能力に依存し、インピーダンスを測定す
ることで極板の単位面積あたりの充放電能力を推定でき
る。具体的には、正極板を作用極としリチウム金属を対
極に用いた電気化学セルにおいて10kHzから10m
Hzの周波数領域でインピーダンスを測定し複素平面上
に結果を記述したときに描く半円弧の直径をR1とし、
負極板を作用極としリチウム金属を対極に用いた電気化
学セルにおいて10kHzから10mHzの周波数領域
でインピーダンスを測定し複素平面上に結果を記述した
ときに描く半円弧の直径をR2とする。この半円弧の直
径Rは、電解液との界面で極板がイオンと電子の授受を
行う際に生じる抵抗の大きさを表す。図3に、この複素
平面上に描かれた半円弧の直径Rを測定した例を示す。Whether the cause of deterioration of the cycle life of the battery is caused by the positive electrode or the negative electrode depends on the charge / discharge capacity per unit area of the positive electrode and the negative electrode. Can be estimated. Specifically, in an electrochemical cell using a positive electrode plate as a working electrode and lithium metal as a counter electrode, 10 kHz to 10 m
The impedance of a semicircular arc drawn when measuring the impedance in the frequency domain of Hz and describing the result on a complex plane is R1,
In an electrochemical cell using a negative electrode plate as a working electrode and lithium metal as a counter electrode, impedance is measured in a frequency range of 10 kHz to 10 mHz, and the diameter of a semicircular arc drawn when the result is described on a complex plane is R2. The diameter R of the semicircle represents the magnitude of the resistance generated when the electrode plate exchanges ions and electrons at the interface with the electrolytic solution. FIG. 3 shows an example in which the diameter R of a semicircular arc drawn on this complex plane is measured.
【0019】R1/R2の値が1以上の場合、正極の充
放電能力が負極を下回り正極で劣化する状態になりやす
く、正極板に極板の電位を確認し得る端子を設け、正極
電位により充放電を規制することで理想的な充放電を行
うことができる。When the value of R1 / R2 is 1 or more, the charge / discharge capacity of the positive electrode is lower than that of the negative electrode and tends to be deteriorated at the positive electrode. The positive electrode plate is provided with a terminal capable of confirming the potential of the electrode plate. By regulating charging and discharging, ideal charging and discharging can be performed.
【0020】また、R1/R2の値が3以下の場合、負
極の充放電能力が正極を下回り正極で劣化する状態にな
りやすく、負極板に極板の電位を確認し得る端子を設
け、負極電位により充放電を規制することで理想的な充
放電を行うことができる。When the value of R1 / R2 is 3 or less, the charge / discharge capacity of the negative electrode is lower than that of the positive electrode and tends to be deteriorated at the positive electrode. The negative electrode plate is provided with a terminal capable of confirming the potential of the electrode plate. Ideal charging and discharging can be performed by regulating charging and discharging by the potential.
【0021】さらに、R1/R2の値が1以上3以下の
場合、正極で劣化する場合と負極で劣化する場合とがあ
り得る。劣化がどちらの極から始まるかは電池の極板形
状や、結着剤、導電材などの種類により左右され、さら
には使用条件によっても異なる。このように、正極と負
極の充放電能力が近接した領域(R1/R2の値が1以
上且つ3以下の領域)においては、正極と負極との両方
の電位をそれぞれ測定し、電池の劣化状態に合わせ充放
電規制を行うことが望ましい。Further, when the value of R1 / R2 is 1 or more and 3 or less, there may be a case where deterioration occurs at the positive electrode and a case where deterioration occurs at the negative electrode. Which pole the deterioration starts from depends on the shape of the electrode plate of the battery, the type of the binder, the conductive material, and the like, and further depends on the use conditions. As described above, in the region where the charge and discharge capacities of the positive electrode and the negative electrode are close to each other (region where the value of R1 / R2 is 1 or more and 3 or less), the potentials of both the positive electrode and the negative electrode are measured, and the deterioration state of the battery is measured. It is desirable to regulate charging and discharging in accordance with the requirements.
【0022】また、電極の電位を確認し得る端子は、極
板面積0.1m2/gあたりに1個以上設けることが望
ましい。少ないと、上記充放電制御方法の効果が小さく
なるからである。It is desirable to provide one or more terminals capable of confirming the potential of the electrode per electrode plate area of 0.1 m 2 / g. If the amount is small, the effect of the charge / discharge control method becomes small.
【0023】また、この充放電制御は極板面積が大きな
電池、例えば、電気自動車用電池等の放電容量が4Ah
以上の電池に用いると特に効果が大きい。This charge / discharge control is performed for a battery having a large electrode plate area, for example, a battery having a discharge capacity of 4 Ah for an electric vehicle.
The effect is particularly great when used in the above batteries.
【0024】[0024]
【実施例】以下、実施例により本発明をさらに詳しく説
明する。ただし、本発明はこれらの実施例に限定される
ものではない。The present invention will be described in more detail with reference to the following examples. However, the present invention is not limited to these examples.
【0025】(実施例1)図1に本発明における円筒型
電池の縦断面図を示す。(Example 1) FIG. 1 is a longitudinal sectional view of a cylindrical battery according to the present invention.
【0026】負極板は、黒鉛95重量%と結着剤のポリ
フッ化ビニリデン樹脂5重量%を混合し、これらをカル
ボキシメチルセルロースの1%水溶液に分散させてスラ
リーを作製し、銅箔からなる負極集電体上に塗布し、乾
燥後、圧延して作製した。尚、黒鉛はティムカル製SF
G44をターボミルによる粉砕と粒度調整を行うことで
比表面積が3m2/g、湿式レーザ粒度計による粒径が
15〜22μmの範囲内としたものである。The negative electrode plate is prepared by mixing 95% by weight of graphite and 5% by weight of polyvinylidene fluoride resin as a binder and dispersing them in a 1% aqueous solution of carboxymethylcellulose to form a slurry. It was applied on an electric body, dried and then rolled. Graphite is Timcal SF
G44 is subjected to pulverization by a turbo mill and particle size adjustment to have a specific surface area of 3 m 2 / g and a particle size of 15 to 22 μm by a wet laser particle size meter.
【0027】一方、正極板は、コバルト酸リチウム粉末
85重量%に対し、導電剤の炭素粉末10重量%と結着
剤のポリフッ化ビニリデン樹脂5重量%を混合し、これ
らをカルボキシメチルセルロースの1%水溶液にに分散
させてスラリーを作製し、アルミ箔からなる正極集電体
上に塗布し、乾燥後、圧延して作製した。尚、コバルト
酸リチウムは、比表面積が0.4m2/gのものを用い
た。On the other hand, for the positive electrode plate, 10% by weight of carbon powder as a conductive agent and 5% by weight of polyvinylidene fluoride resin as a binder were mixed with 85% by weight of lithium cobalt oxide powder, and these were mixed with 1% of carboxymethyl cellulose. A slurry was prepared by dispersing the slurry in an aqueous solution, applied on a positive electrode current collector made of aluminum foil, dried, and then rolled. Here, lithium cobaltate having a specific surface area of 0.4 m 2 / g was used.
【0028】上記のように作成した正極板及び負極板
を、セパレータを介して複数回渦巻状に巻回して極板群
4を形成し、電池ケース1内に収容した。また、正極板
からは正極リード5を引き出して封口板2に接続し、負
極板からは負極リード6が引き出して電池ケース1の底
部に接続した。さらに、極板群4の上下部にはそれぞれ
絶縁リング7を設けた。The positive electrode plate and the negative electrode plate prepared as described above were spirally wound a plurality of times with a separator interposed therebetween to form an electrode plate group 4 and housed in the battery case 1. Further, the positive electrode lead 5 was pulled out from the positive electrode plate and connected to the sealing plate 2, and the negative electrode lead 6 was drawn out from the negative electrode plate and connected to the bottom of the battery case 1. Further, insulating rings 7 were provided on the upper and lower portions of the electrode plate group 4 respectively.
【0029】また、極板群4と電池ケース1の間には参
照電極8を挿入した。この参照電極8にはリチウムの金
属箔を用い、金属箔の表面とリード部をセパレータで覆
うことにより電気的な絶縁を行っている。A reference electrode 8 was inserted between the electrode group 4 and the battery case 1. The reference electrode 8 is made of lithium metal foil, and electrical insulation is performed by covering the surface of the metal foil and the lead with a separator.
【0030】そして、エチレンカーボネートとエチルメ
チルカーボネートの体積比1:1の混合溶媒に、LiP
F6を1.5モル/リットル溶解した有機電解液を注入
し、封口板2を用いて電池を形成した。このようにし
て、直径18mm、高さ650mmの円筒型電池を作製
した。尚、この電池の極板を用いてR1/R2の比を測
定したところR1/R2=4.6となった。Then, LiP was added to a mixed solvent of ethylene carbonate and ethyl methyl carbonate at a volume ratio of 1: 1.
An organic electrolyte solution in which 1.5 mol / l of F 6 was dissolved was injected, and a battery was formed using the sealing plate 2. Thus, a cylindrical battery having a diameter of 18 mm and a height of 650 mm was produced. When the ratio of R1 / R2 was measured using the electrode plate of this battery, R1 / R2 = 4.6.
【0031】この円筒型電池を用い、参照電極により測
定した正極の電位の上限が4.3VのCVCC充電を行
い、最大制限電流を1Aとし、電流が100mAになっ
た時点で充電終了とした。放電は1400mAの定電流
で電池電圧が3.0Vになるまで行い、充放電切り替え
時の休止時間は20分としてサイクル試験を行った。
尚、充放電は20℃の恒温槽の中で行った。尚、この正
極の電位の上限は、後述する比較例1の電池を充電した
時における正極電位を参考にして決定した。Using this cylindrical battery, CVCC charging was performed in which the upper limit of the potential of the positive electrode measured by the reference electrode was 4.3 V, the maximum limiting current was 1 A, and the charging was terminated when the current reached 100 mA. Discharge was performed at a constant current of 1400 mA until the battery voltage reached 3.0 V, and a cycle test was performed with a pause time of 20 minutes during switching between charge and discharge.
The charge and discharge were performed in a constant temperature bath at 20 ° C. The upper limit of the positive electrode potential was determined with reference to the positive electrode potential when the battery of Comparative Example 1 described later was charged.
【0032】(実施例2)実施例1と同様に円筒型電池
を作製し、参照電極により測定した負極の電位の下限が
0.1VのCVCC充電を行い、最大制限電流を1Aと
し、電流が100mAになった時点で充電終了とした。
その他の条件は実施例1と同様の条件によりサイクル試
験を行った。尚、この正極の電位の上限は、後述する比
較例1の電池を充電した時における負極電位を参考にし
て決定した。Example 2 A cylindrical battery was manufactured in the same manner as in Example 1, and the lower limit of the potential of the negative electrode measured by the reference electrode was CVCC charged at a lower limit of 0.1 V. The charging was terminated when the current reached 100 mA.
The cycle test was performed under the same conditions as in Example 1 except for the above conditions. The upper limit of the potential of the positive electrode was determined with reference to the negative electrode potential when the battery of Comparative Example 1 described later was charged.
【0033】(比較例1)実施例1と同様に円筒型電池
を作製し、電池自身の電圧の上限が4.2VのCVCC
充電を行い、最大制限電流を1Aとし、電流が100m
Aになった時点で充電終了とした。その他の条件は実施
例1と同様の条件によりサイクル試験を行った。尚、参
照電極8は設けなかった。Comparative Example 1 A cylindrical battery was manufactured in the same manner as in Example 1, and the upper limit of the voltage of the battery itself was 4.2 V.
Charge the battery, set the maximum current limit to 1A, and set the current to 100m
The charging was terminated when the battery reached A. The cycle test was performed under the same conditions as in Example 1 except for the above conditions. Note that the reference electrode 8 was not provided.
【0034】(実施例3)正極材料に用いたコバルト酸
リチウムを、比表面積が1.2m2/gのものとした以
外は実施例1と同様の方法で円筒型電池を作製し、実施
例1と同様の充電条件によってサイクル試験を行った。
尚、この電池の極板を用いてR1/R2の比を測定した
ところR1/R2=1.1となった。Example 3 A cylindrical battery was manufactured in the same manner as in Example 1 except that the lithium cobaltate used as the positive electrode material had a specific surface area of 1.2 m 2 / g. A cycle test was performed under the same charging conditions as in No. 1.
When the ratio of R1 / R2 was measured using the electrode plate of this battery, R1 / R2 = 1.1.
【0035】(実施例4)実施例3と同様に円筒型電池
を作製し、実施例2と同様の充電条件によってサイクル
試験を行った。Example 4 A cylindrical battery was manufactured in the same manner as in Example 3, and a cycle test was performed under the same charging conditions as in Example 2.
【0036】(比較例2)実施例3と同様に円筒型電池
を作製し、比較例1と同様の充電条件によってサイクル
試験を行った。尚、参照電極8は設けなかった。Comparative Example 2 A cylindrical battery was manufactured in the same manner as in Example 3, and a cycle test was performed under the same charging conditions as in Comparative Example 1. Note that the reference electrode 8 was not provided.
【0037】(実施例5)図2に本発明におけるシート
状電池の構成図を示す。Example 5 FIG. 2 shows a configuration diagram of a sheet-shaped battery according to the present invention.
【0038】正極板9及び負極板10は実施例1の正極
板及び負極板と同様に作製し、所定の設定寸法に切り出
した。尚、正極のサイズは、長さ220cm、幅22c
m、負極のサイズは、長さ220.5cm、幅22.5
cmとした(極板面積0.484m2〜0.496
m2)。The positive electrode plate 9 and the negative electrode plate 10 were manufactured in the same manner as the positive electrode plate and the negative electrode plate of Example 1, and were cut into predetermined dimensions. The size of the positive electrode is 220 cm in length and 22 c in width.
m, the size of the negative electrode is 220.5 cm in length and 22.5 in width
cm (electrode plate area: 0.484 m 2 to 0.496
m 2 ).
【0039】この正極板9及び負極板10を、セパレー
タ12a、12bを介して重ね合わせて、極板全体を覆
うようにアルミを芯材としたラミネート袋に挿入した。
尚、正極板9の長辺からは正極リード9aを引き出し、
負極板10の長辺からは負極リード10aを引き出し
た。正極リード9aと負極リード10aは、セパレータ
12a、12bを介して対向する位置に配置した。さら
に、対となっている正極リード9aと負極リード10a
の間に、参照電極11を配置しこれをセパレータ12
a、12bの間に挿入した。正極リード9aと負極リー
ド10aと参照電極11および参照電極リード11aと
で1対とし、以下このリードの対をリード対と称す。The positive electrode plate 9 and the negative electrode plate 10 were overlapped via the separators 12a and 12b, and inserted into a laminate bag made of aluminum as a core material so as to cover the entire electrode plate.
In addition, the positive electrode lead 9a is pulled out from the long side of the positive electrode plate 9,
A negative electrode lead 10a was drawn out from the long side of the negative electrode plate 10. The positive electrode lead 9a and the negative electrode lead 10a were arranged at positions facing each other with the separators 12a and 12b interposed therebetween. Furthermore, a pair of the positive electrode lead 9a and the negative electrode lead 10a
The reference electrode 11 is disposed between the
a, inserted between 12b. One pair of the positive electrode lead 9a, the negative electrode lead 10a, the reference electrode 11, and the reference electrode lead 11a is hereinafter referred to as a lead pair.
【0040】このリード対をA端とB端に1対ずつ合計
2対配置した。これらのリードは全てラミネート袋の外
部に引き出し充放電の制御を行う装置に接続した。ラミ
ネート袋やリード板は、耐有機電解液性の電子伝導性を
もつ金属や合金を用いることができる。例えば、鉄、ニ
ッケル、チタン、クロム、モリブデン、銅、アルミニウ
ムなどの金属あるいはそれらの合金が用いられる。そし
て、電解液を注入し、ラミネート袋の開口部を熱溶着し
てシールを行い、シート状電池を作製した。A total of two pairs of the lead pairs were arranged at the A and B ends. These leads were all connected to a device that controls the charge / discharge drawn out of the laminate bag. For the laminate bag or the lead plate, a metal or an alloy having an organic electrolyte resistance and electron conductivity can be used. For example, metals such as iron, nickel, titanium, chromium, molybdenum, copper, and aluminum or alloys thereof are used. Then, an electrolytic solution was injected, and the opening of the laminate bag was heat-sealed to seal, thereby producing a sheet-shaped battery.
【0041】またラミネート袋をケースとした電池は極
板の密着性が悪くなるため、袋の外側よりステンレス製
の2枚の板で電池を挟みこみ固定した。尚、今回は電池
のケースとしてラミネート袋を用いたがこれらは、上記
した構造を有していれば実施例1に示すような形状が固
定されたケースを用いてもよい。また、形状においても
シート状電池に限らず極板を複数回渦巻状に巻回された
円筒型電池、または複数回織り込んで作成した角型電池
としてもよい。Since a battery using a laminated bag as a case has poor adhesion to the electrode plates, the battery was sandwiched and fixed between two stainless steel plates from the outside of the bag. In this case, a laminate bag is used as a battery case, but a case in which the shape as shown in the first embodiment is fixed may be used as long as it has the above-described structure. The shape of the battery is not limited to the sheet battery, but may be a cylindrical battery in which an electrode plate is spirally wound a plurality of times, or a rectangular battery formed by weaving a plurality of times.
【0042】このシート状電池を用い、参照電極により
測定した正極の電位の上限が4.3VのCVCC充電を
行い、最大制限電流を8Aとし、電流が800mAにな
った時点で充電終了とした。放電は11.2Aの定電流
で3.0Vになるまで放電し、充放電切り替え時の休止
時間は20分としてサイクル試験を行った。ただし、充
放電の制御を各端子ごとに独立に行った。尚、充放電は
20℃の恒温槽の中で行った(端子1個当たりの正極面
積0.242m2)。Using this sheet-shaped battery, CVCC charging was performed with the upper limit of the potential of the positive electrode measured by the reference electrode being 4.3 V, the maximum limiting current was set to 8 A, and the charging was terminated when the current reached 800 mA. Discharge was performed at a constant current of 11.2 A until the voltage reached 3.0 V, and a cycle test was performed with a pause time of 20 minutes during switching between charge and discharge. However, charge and discharge were controlled independently for each terminal. The charge / discharge was performed in a thermostat at 20 ° C. (positive electrode area per terminal: 0.242 m 2 ).
【0043】(実施例6)リード対をA端とB端との間
に等間隔に4対配置した以外は、実施例5と同様にシー
ト状電池を作製した。また、サイクル試験についても実
施例5と同様に行った(端子1個当たりの正極面積0.
161m2)。(Example 6) A sheet-shaped battery was produced in the same manner as in Example 5, except that four pairs of lead pairs were arranged at equal intervals between the end A and the end B. The cycle test was also performed in the same manner as in Example 5 (the positive electrode area per terminal was 0.1 mm).
161 m 2 ).
【0044】(実施例7)リード対をA端とB端との間
に等間隔に5対配置した以外は、実施例5と同様にシー
ト状電池を作製した。また、サイクル試験についても実
施例5と同様に行った(端子1個当たりの正極面積0.
097m2)。Example 7 A sheet-shaped battery was manufactured in the same manner as in Example 5, except that five pairs of lead pairs were arranged at equal intervals between the end A and the end B. The cycle test was also performed in the same manner as in Example 5 (the positive electrode area per terminal was 0.1 mm).
097 m 2 ).
【0045】(実施例8)リード対をA端とB端との間
に等間隔に6対配置した以外は、実施例5と同様にシー
ト状電池を作製した。また、サイクル試験についても実
施例5と同様に行った(端子1個当たりの正極面積0.
081m2)。(Example 8) A sheet-shaped battery was manufactured in the same manner as in Example 5, except that six pairs of lead pairs were arranged at equal intervals between the end A and the end B. The cycle test was also performed in the same manner as in Example 5 (the positive electrode area per terminal was 0.1 mm).
081 m 2 ).
【0046】(実施例9)リード対をA端とB端との間
に等間隔に8対配置した以外は、実施例5と同様にシー
ト状電池を作製した。また、サイクル試験についても実
施例5と同様に行った(端子1個当たりの正極面積0.
061m2)。(Example 9) A sheet-shaped battery was manufactured in the same manner as in Example 5, except that eight pairs of lead pairs were arranged at equal intervals between the end A and the end B. The cycle test was also performed in the same manner as in Example 5 (the positive electrode area per terminal was 0.1 mm).
061 m 2 ).
【0047】(実施例10)リード対をA端に1対のみ
配置した以外は、実施例5と同様にシート状電池を作製
した。また、サイクル試験についても実施例5と同様に
行った(端子1個当たりの正極面積0.484m2)。(Example 10) A sheet-shaped battery was produced in the same manner as in Example 5, except that only one pair of the lead pairs was arranged at the end A. The cycle test was also performed in the same manner as in Example 5 (positive electrode area per terminal: 0.484 m 2 ).
【0048】《評価》実施例1、実施例2及び比較例1
のサイクル試験の結果を(表1)に示す。尚、上記充放
電条件によるサイクルを繰り返し、1サイクル目の放電
容量を100%としたときの電池の放電容量が50%ま
で減少したときのサイクル数を電池のサイクル寿命とし
てサイクル特性の評価の指標とした。<< Evaluation >> Examples 1, 2 and Comparative Example 1
(Table 1) shows the results of the cycle test. The cycle under the above charge / discharge conditions is repeated, and the number of cycles when the discharge capacity of the battery is reduced to 50% when the discharge capacity in the first cycle is 100% is defined as the cycle life of the battery. And
【0049】[0049]
【表1】 これらの電池は、正極材料に用いたコバルト酸リチウム
の比表面積が0.4m 2/gと非常に小さく、また、正
極と負極の充放電能力を比較するためのR1/R2が
4.6であることから、負極よりも先に正極の劣化が生
じる設計となっている。そのため、サイクルを経過する
と負極の容量よりも正極の容量が少なくなる。このよう
な状態の電池に比較例1のような従来の充電方法である
CVCC充電を行うと、正極が過充電状態となり、正極
の劣化を促進する結果となる。これに対し、実施例1の
ような本発明の充放電制御方法では、正極電位を基準に
して充電を行うため正極の容量減少に合わせた充電が可
能となっている。すなわち、劣化した正極にさらに過剰
な負荷を与えることがないため、サイクルの寿命特性が
向上しているのが確認できた。また、実施例2では、負
極の電位を基準にして充電を行うため、正極の容量減少
に合わせては充電ができない。そのため正極が負極より
も先に劣化する電池においては、サイクル寿命を向上さ
せる効果がなく、比較例1とほぼ同様のサイクル寿命特
性を示している。[Table 1]These batteries use the lithium cobaltate used for the cathode material.
0.4m specific surface area Two/ G and very small
R1 / R2 for comparing the charge and discharge capacity of the pole and the anode is
4.6, the deterioration of the positive electrode occurs before the negative electrode.
It is designed to work. So it goes through a cycle
The capacity of the positive electrode is smaller than the capacity of the negative electrode. like this
And a conventional charging method as in Comparative Example 1
When CVCC charging is performed, the positive electrode becomes overcharged,
As a result, the deterioration of the material is promoted. In contrast, the first embodiment
In such a charge / discharge control method of the present invention, the positive electrode potential is used as a reference.
To charge according to the decrease in the capacity of the positive electrode.
Noh. In other words, the excess
Cycle life characteristics
It was confirmed that it had improved. In the second embodiment, the negative
Reduces the capacity of the positive electrode because charging is performed based on the potential of the electrode
Can not be charged according to. Therefore, the positive electrode is
Batteries that deteriorate earlier also have a longer cycle life.
Cycle life characteristics similar to Comparative Example 1.
Shows sex.
【0050】次に、実施例3、実施例4及び比較例2の
サイクル試験の結果を(表2)に示す。サイクル特性の
評価の指標は先述したとおりである。Next, the results of the cycle tests of Example 3, Example 4, and Comparative Example 2 are shown in Table 2. The index for evaluating the cycle characteristics is as described above.
【0051】[0051]
【表2】 これらの電池は、正極材料に用いたコバルト酸リチウム
の比表面積が1.2m 2/gと非常に大きく、また、正
極と負極の充放電能力を比較するためのR1/R2が
1.1であることから、正極よりも先に負極の劣化が生
じる設計となっている。そのため、サイクルを経過する
と正極の容量よりも負極の容量が少なくなる。このよう
な状態の電池に比較例2のように従来の充電方法である
CVCC充電を行うと、負極が過充電状態となり、負極
の劣化を促進する結果となる。これに対し、実施例3の
ような本発明の充放電制御方法では、負極電位を基準に
して充電を行うため負極の容量減少に合わせた充電が可
能となっている。すなわち、劣化した負極にさらに過剰
な負荷を与えることがないため、サイクルの寿命特性が
向上しているのが確認できた。また、実施例4では、正
極の電位を基準にして充電を行うため、負極の容量減少
に合わせては充電ができない。そのため負極が正極より
も先に劣化する電池においては、サイクル寿命を向上さ
せる効果がなく、比較例2とほぼ同様のサイクル寿命特
性を示している。[Table 2]These batteries use the lithium cobaltate used for the cathode material.
1.2m specific surface area Two/ G and very large
R1 / R2 for comparing the charge and discharge capacity of the pole and the anode is
1.1, the negative electrode deteriorates before the positive electrode.
It is designed to work. So it goes through a cycle
The capacity of the negative electrode is smaller than the capacity of the positive electrode. like this
The conventional charging method as in Comparative Example 2 is applied to a battery in a good state.
When CVCC charging is performed, the negative electrode becomes overcharged and the negative electrode becomes overcharged.
As a result, the deterioration of the material is promoted. In contrast, the third embodiment
In such a charge / discharge control method of the present invention, the negative electrode potential is used as a reference.
To charge according to the capacity reduction of the negative electrode.
Noh. In other words, the excess
Cycle life characteristics
It was confirmed that it had improved. In the fourth embodiment,
Reduces the capacity of the negative electrode because charging is performed based on the potential of the electrode
Can not be charged according to. Therefore, the negative electrode is
Batteries that deteriorate earlier also have a longer cycle life.
Cycle life characteristics similar to Comparative Example 2
Shows sex.
【0052】尚、本実施例では充電最大電流を1Aと
し、充電電圧を4.2Vとした定電流定電圧充電とした
が、他の充電電圧、充電電流値の場合や、パルス充電に
おいても同様の結果が得られた。In the present embodiment, the maximum charging current is set to 1 A, and the charging voltage is set to 4.2 V. The constant current and constant voltage charging is used. However, the same applies to other charging voltages and charging current values and pulse charging. Was obtained.
【0053】また、正極材料のコバルト酸リチウムの比
表面積を変え、R1/R2が異なる極板をいくつか作成
したところ、正極の方が先に劣化する設計である1以
上、特に2.5を超える場合に顕著な効果を示した。
尚、上記実施例3ではR1/R2が1.1の極板を用い
て正極電位を制御する方法において数%のサイクル特性
の向上しか見られなかったが、極板形状(長さ、幅等)
を変えてR1/R2が1.05の極板を用いて正極電位
を制御する方法で同様の実験を行ったところ30%程の
サイクル特性の向上が見られた。一方、負極の方が先に
劣化する設計である3以下、特に2以下の場合に顕著な
効果を示した。Further, when the specific surface area of lithium cobalt oxide as the positive electrode material was changed and several electrode plates having different R1 / R2 were prepared, one or more, particularly 2.5, which was designed so that the positive electrode deteriorated earlier When it exceeded, a remarkable effect was shown.
In the third embodiment, the cycle characteristic was improved by only several% in the method of controlling the positive electrode potential using the electrode plate having R1 / R2 of 1.1, but the electrode plate shape (length, width, etc.) was not improved. )
When the same experiment was performed by changing the value and controlling the positive electrode potential using an electrode plate having R1 / R2 of 1.05, an improvement in cycle characteristics of about 30% was found. On the other hand, the negative electrode exhibited a remarkable effect when it was designed to deteriorate earlier than 3 or less, especially when it was 2 or less.
【0054】次に、実施例5〜10のサイクル試験の結
果を(表3)に示す。但し、リード対が複数本存在する
実施例5〜7では、充放電の制御を各端子ごとに独立に
行い、 (各端子に流す充電時の最大電流)=8/(極板に配置
されたリード対の数)A (各端子に流す放電電流)=11.2/(極板に配置さ
れたリード対の数)A とした。尚、サイクル特性の評価の指標は先述したとお
りである。サイクル特性試験の結果を(表3)に示す。Next, the results of the cycle tests of Examples 5 to 10 are shown in Table 3. However, in Examples 5 to 7 in which there are a plurality of lead pairs, charging / discharging control is performed independently for each terminal, and (maximum current at the time of charging flowing to each terminal) = 8 / (disposed on the electrode plate). Number of lead pairs) A (discharge current flowing through each terminal) = 11.2 / (number of lead pairs arranged on electrode plate) A The index for evaluating the cycle characteristics is as described above. Table 3 shows the results of the cycle characteristic test.
【0055】[0055]
【表3】 実施例5〜10ともにサイクル寿命特性が向上している
が、実施例5〜7、実施例6は、実施例8に比べ飛躍的
にサイクル寿命特性が向上していることがわかる。極板
のサイズが大きくなると、電流を流すことによって極板
内に生じる電位分布が大きくなり、1つの極板内で充電
状態を均一に保つのが困難となる。そこで、実施例5〜
7のように複数のリード対を極板に配置し、極板中に存
在する異なる充電状態に合わせて独立に充電を行うこと
で、極板全体として均一な充電を行うことができる。こ
れにより、一部の領域のみで劣化が促進され電池のサイ
クル寿命が低下することを防ぎ、電池のサイクル寿命特
性を飛躍的に向上できることが確認できた。[Table 3] Although the cycle life characteristics of Examples 5 to 10 are improved, the cycle life characteristics of Examples 5 to 7 and Example 6 are remarkably improved as compared with Example 8. When the size of the electrode plate is increased, a potential distribution generated in the electrode plate by flowing a current becomes large, and it becomes difficult to maintain a uniform charged state in one electrode plate. Then, Example 5
By arranging a plurality of lead pairs on the electrode plate as shown in FIG. 7 and performing independent charging in accordance with different charging states existing in the electrode plate, uniform charging can be performed as the entire electrode plate. Thus, it was confirmed that the deterioration of the cycle life of the battery was prevented from being reduced due to accelerated deterioration in only a part of the region, and the cycle life characteristics of the battery could be significantly improved.
【0056】[0056]
【発明の効果】本発明は、正極もしくは負極の極板が1
個以上の電位を確認し得る端子を有し、各端子から得ら
れる電位を参照して各端子が独立に充放電を行うこと
で、極板面積の広い電池やサイクル経過後の電池におい
て、極板上で生じる充電の不均一や、容量減少に伴う活
物質の過充電を抑制することが可能となり、サイクル特
性に優れた非水電解質二次電池が得られる。According to the present invention, the positive electrode or the negative electrode has one plate.
In the case of a battery having a large plate area or a battery after a cycle, the terminal has at least one terminal capable of confirming a potential, and each terminal independently charges and discharges with reference to the potential obtained from each terminal. Non-uniform charging on the plate and overcharging of the active material due to a decrease in capacity can be suppressed, and a nonaqueous electrolyte secondary battery with excellent cycle characteristics can be obtained.
【図面の簡単な説明】[Brief description of the drawings]
【図1】本発明の円筒電池の縦断面図FIG. 1 is a longitudinal sectional view of a cylindrical battery of the present invention.
【図2】本発明のシート電池の構造図FIG. 2 is a structural diagram of a sheet battery of the present invention.
【図3】インピーダンス測定の複素表面図FIG. 3 is a complex surface diagram of impedance measurement.
1 電池ケース 2 封口板 3 絶縁パッキング 4 極板群 5 正極リード 6 負極リード 7 絶縁リング 8 参照電極 9 正極板 9a 正極リード 10 負極板 10a 負極リード 11 参照電極 11a 参照電極リード 12a セパレータ 12b セパレータ DESCRIPTION OF SYMBOLS 1 Battery case 2 Sealing plate 3 Insulating packing 4 Electrode plate group 5 Positive electrode lead 6 Negative electrode lead 7 Insulating ring 8 Reference electrode 9 Positive electrode plate 9a Positive electrode lead 10 Negative electrode plate 10a Negative electrode lead 11 Reference electrode 11a Reference electrode lead 12a Separator 12b Separator
───────────────────────────────────────────────────── フロントページの続き (72)発明者 木宮 宏和 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 (72)発明者 芳澤 浩司 大阪府門真市大字門真1006番地 松下電器 産業株式会社内 Fターム(参考) 5H022 AA09 BB08 BB27 CC02 CC21 5H029 AJ02 AJ05 AK03 AL07 AM03 AM07 BJ02 BJ14 CJ16 CJ28 DJ05 HJ00 HJ07 HJ16 HJ20 5H030 AA03 AA10 AS05 BB02 BB18 BB21 FF41 ──────────────────────────────────────────────────の Continuing on the front page (72) Inventor Hirokazu Kimiya 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture Inside Matsushita Electric Industrial Co., Ltd. Terms (reference) 5H022 AA09 BB08 BB27 CC02 CC21 5H029 AJ02 AJ05 AK03 AL07 AM03 AM07 BJ02 BJ14 CJ16 CJ28 DJ05 HJ00 HJ07 HJ16 HJ20 5H030 AA03 AA10 AS05 BB02 BB18 BB21 FF41
Claims (10)
極を備えた非水電解質二次電池の充放電制御方法におい
て、前記正極の極板が1個以上の電位を確認し得る端子
を有し、各端子から得られる電位を参照して各端子が独
立に充放電を行うことを特徴とする非水電解質二次電池
の充放電制御方法。1. A charge / discharge control method for a nonaqueous electrolyte secondary battery having a positive electrode and a negative electrode capable of inserting and extracting lithium, wherein the positive electrode plate has one or more terminals capable of confirming a potential. A charge / discharge control method for a non-aqueous electrolyte secondary battery, wherein each terminal independently charges and discharges with reference to a potential obtained from each terminal.
対極に用いた電気化学セルにおいて10kHzから10
mHzの周波数領域でインピーダンスを測定し複素平面
上に結果を記述したときに描く半円弧の直径をR1と
し、負極の極板を作用極としリチウム金属を対極に用い
た電気化学セルにおいて10kHzから10mHzの周
波数領域でインピーダンスを測定し複素平面上に結果を
記述したときに描く半円弧の直径をR2としたとき、R
1/R2の値が1以上であることを特徴とする請求項1
記載の非水電解質二次電池の充放電制御方法。2. An electrochemical cell using a positive electrode plate as a working electrode and lithium metal as a counter electrode.
The impedance of a semicircular arc drawn when measuring the impedance in the frequency domain of mHz and describing the result on a complex plane is defined as R1, the negative electrode plate is used as a working electrode, and an electrochemical cell using lithium metal as a counter electrode is from 10 kHz to 10 mHz. When the diameter of the semicircular arc drawn when measuring the impedance in the frequency domain of and describing the result on the complex plane is R2, R
2. The value of 1 / R2 is 1 or more.
The charge / discharge control method of the nonaqueous electrolyte secondary battery according to the above.
極を備えた非水電解質二次電池の充放電制御方法におい
て、前記負極の極板が1個以上の電位を確認し得る端子
を有し、各端子から得られる電位を参照して各端子が独
立に充放電を行うことを特徴とする非水電解質二次電池
の充放電制御方法。3. A charge / discharge control method for a nonaqueous electrolyte secondary battery having a positive electrode and a negative electrode capable of inserting and extracting lithium, wherein the negative electrode plate has one or more terminals capable of confirming a potential. A charge / discharge control method for a non-aqueous electrolyte secondary battery, wherein each terminal independently charges and discharges with reference to a potential obtained from each terminal.
対極に用いた電気化学セルにおいて10kHzから10
mHzの周波数領域でインピーダンスを測定し複素平面
上に結果を記述したときに描く半円弧の直径をR1と
し、負極の極板を作用極としリチウム金属を対極に用い
た電気化学セルにおいて10kHzから10mHzの周
波数領域でインピーダンスを測定し複素平面上に結果を
記述したときに描く半円弧の直径をR2としたとき、R
1/R2の値が3以下であることを特徴とする請求項3
記載の非水電解質二次電池の充放電制御方法。4. An electrochemical cell using a positive electrode plate as a working electrode and lithium metal as a counter electrode has a frequency of 10 kHz to 10 kHz.
The impedance of a semicircular arc drawn when measuring the impedance in the frequency domain of mHz and describing the result on a complex plane is defined as R1, the negative electrode plate is used as a working electrode, and an electrochemical cell using lithium metal as a counter electrode is from 10 kHz to 10 mHz. When the diameter of the semicircular arc drawn when measuring the impedance in the frequency domain of and describing the result on the complex plane is R2, R
4. The value of 1 / R2 is 3 or less.
The charge / discharge control method of the nonaqueous electrolyte secondary battery according to the above.
極を備えた非水電解質二次電池の充放電制御方法におい
て、前記正極と負極の極板が共に1対以上の電位を確認
し得る端子対を有し、各端子から得られる電位を参照し
て各端子対が独立に充放電を行うことを特徴とする非水
電解質二次電池の充放電制御方法。5. A charge / discharge control method for a non-aqueous electrolyte secondary battery having a positive electrode and a negative electrode capable of inserting and extracting lithium, wherein the positive and negative electrode plates can confirm one or more pairs of potentials. A charge / discharge control method for a non-aqueous electrolyte secondary battery, comprising: a terminal pair, wherein each terminal pair independently charges and discharges with reference to a potential obtained from each terminal.
対極に用いた電気化学セルにおいて10kHzから10
mHzの周波数領域でインピーダンスを測定し複素平面
上に結果を記述したときに描く半円弧の直径をR1と
し、負極の極板を作用極としリチウム金属を対極に用い
た電気化学セルにおいて10kHzから10mHzの周
波数領域でインピーダンスを測定し複素平面上に結果を
記述したときに描く半円弧の直径をR2としたとき、R
1/R2の値が3以下であることを特徴とする請求項5
記載の非水電解質二次電池の充放電制御方法。6. An electrochemical cell using a positive electrode plate as a working electrode and lithium metal as a counter electrode, from 10 kHz to 10 kHz.
The impedance of a semicircular arc drawn when measuring the impedance in the frequency domain of mHz and describing the result on a complex plane is defined as R1, the negative electrode plate is used as a working electrode, and an electrochemical cell using lithium metal as a counter electrode is from 10 kHz to 10 mHz. When the diameter of the semicircular arc drawn when measuring the impedance in the frequency domain of and describing the result on the complex plane is R2, R
6. The value of 1 / R2 is 3 or less.
The charge / discharge control method of the nonaqueous electrolyte secondary battery according to the above.
制御方法を用いる非水電解質二次電池。7. A non-aqueous electrolyte secondary battery using the charge / discharge control method according to claim 1.
極を備えた非水電解質二次電池において、電池内に1個
以上の参照電極を有し、さらに正極または負極の極板に
2個以上の電位を確認し得る端子を有し、この各端子は
互いに接しておらず独立していることを特徴とする非水
電解質二次電池。8. A non-aqueous electrolyte secondary battery comprising a positive electrode and a negative electrode capable of inserting and extracting lithium, wherein the battery has one or more reference electrodes, and two non-aqueous electrodes are provided on the positive or negative electrode plate. A non-aqueous electrolyte secondary battery having terminals capable of confirming the above potentials, wherein the terminals are not in contact with each other and are independent.
(極板面積)/(0.1m2)個以上であることを特徴
とする請求項8記載の非水電解質二次電池。9. A terminal provided on a positive electrode plate or a negative electrode plate,
9. The non-aqueous electrolyte secondary battery according to claim 8, wherein (electrode plate area) / (0.1 m 2 ) or more.
求項8に記載の非水電解質二次電池。10. The non-aqueous electrolyte secondary battery according to claim 8, wherein the battery has a discharge capacity of 4 Ah or more.
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JP2013131398A (en) * | 2011-12-21 | 2013-07-04 | Toyota Motor Corp | Battery system |
JP2013214409A (en) * | 2012-04-02 | 2013-10-17 | Hitachi Maxell Ltd | Wound battery |
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JP2022511350A (en) * | 2019-09-29 | 2022-01-31 | 寧徳新能源科技有限公司 | Charging method, electronic device and storage medium |
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