JP2009281916A - Method for testing battery and electrode - Google Patents

Method for testing battery and electrode Download PDF

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JP2009281916A
JP2009281916A JP2008135305A JP2008135305A JP2009281916A JP 2009281916 A JP2009281916 A JP 2009281916A JP 2008135305 A JP2008135305 A JP 2008135305A JP 2008135305 A JP2008135305 A JP 2008135305A JP 2009281916 A JP2009281916 A JP 2009281916A
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battery
charge
charging
current
battery capacity
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JP5050999B2 (en
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Makiko Kichise
Daigo Takemura
Seiji Yoshioka
省二 吉岡
万希子 吉瀬
大吾 竹村
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Mitsubishi Electric Corp
三菱電機株式会社
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    • YGENERAL 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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Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for testing a battery or electrode capable of correctly and immediately predicting the lifetime of the battery without a short circuit inside the battery. <P>SOLUTION: The method for testing the battery or electrode includes: a charge/discharge cycle process of repeating a first step of constant-current charging the battery at a current rate of 1.5 C or higher to an upper-limit voltage, a second step of continuing a constant-voltage charge by maintaining the upper-limit voltage after the first step until lowering to a predetermined current value, a third step of constant-current discharging the battery at a current rate of 1.5 C or higher after the second step until a predetermined voltage, and a forth step of constant-current discharging the battery at a current rate of 0.5 C or lower after the third step until a lower-limit voltage; and a maintenance battery capacity determination process of determining whether or not to be returned to the charge/discharge cycle process by measuring a maintenance battery capacity of the battery after repeating the charge/discharge cycle process by predetermined times and comparing an initial battery capacity and the maintenance battery capacity. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

この発明は、リチウムイオン電池などの二次電池の寿命を短期間で予測する電池あるいは電極の試験方法に関するものである。   The present invention relates to a battery or electrode testing method for predicting the life of a secondary battery such as a lithium ion battery in a short period of time.
リチウムイオン電池などの二次電池の寿命を評価するための加速劣化試験方法として、環境温度が約50℃のもとでDOD(Depth of Discharge)の浅い充放電サイクルを繰り返す方法が開示されている(例えば、非特許文献1参照)。ここで、DODとは満充電状態から放電した容量をパーセント表示したもので、DODが浅い充放電サイクルとは満充電状態と電圧低下が少ない状態との間で充放電を繰り返すことである。一方、放電電気量を充電電気量より大きくして充放電サイクル試験を加速する方法が開示されている(例えば、特許文献1参照)。   As an accelerated deterioration test method for evaluating the life of a secondary battery such as a lithium ion battery, a method of repeating a shallow charge / discharge cycle of DOD (Depth of Discharge) under an environmental temperature of about 50 ° C. is disclosed. (For example, refer nonpatent literature 1). Here, the DOD is a percentage of the capacity discharged from the fully charged state, and the charging / discharging cycle with a shallow DOD is to repeat charging / discharging between the fully charged state and the state where the voltage drop is small. On the other hand, a method for accelerating the charge / discharge cycle test by making the amount of discharge electricity larger than the amount of charge electricity is disclosed (for example, see Patent Document 1).
特開平10−255858号公報(2頁)JP-A-10-255858 (2 pages)
従来の、環境温度が約50℃のもとでDODの浅い充放電サイクルを繰り返す方法では、ある一定サイクル経過により電池内部で微小短絡が発生し、充電終了までに長時間要する現象が起きるため、1サイクルに時間がかかったり、満充電状態に達しなかったりして電池の劣化が遅くなる問題がある。これは、50℃の高温でDODの浅い充放電を繰り返すことによって、イオンとして電解液中に溶け出した正極活物質中の遷移金属が負極表面もしくはセパレータ中に析出するために電池内部で微小短絡が発生するためである。なお、環境温度を25℃程度の室温にすると、電池の劣化はほとんど発生せず、寿命試験として極めて長時間かかり、早期診断ができないという問題がある。一方、放電電気量を充電電気量より大きくして充放電サイクル試験を加速する方法では、サイクル終了時を電圧で規定しているが、これは電池の過電圧(内部抵抗)の増加により劣化を判断していることになる。しかしながら、電池の内部抵抗増加と残容量とは必ずしも対応しないため、電池の寿命を正確に予測できないという問題点が生じる。   In the conventional method of repeating a charge / discharge cycle with a shallow DOD under an environmental temperature of about 50 ° C., a short circuit occurs inside the battery after a certain cycle, and a phenomenon that takes a long time to complete charging occurs. There is a problem that it takes a long time for one cycle or the battery is not deteriorated slowly due to a failure to reach a fully charged state. This is because the transition metal in the positive electrode active material dissolved in the electrolyte as ions is deposited on the negative electrode surface or in the separator due to repeated charge / discharge with a shallow DOD at a high temperature of 50 ° C. This is because of this. When the ambient temperature is about 25 ° C., the battery hardly deteriorates, and it takes a very long time as a life test, and there is a problem that early diagnosis cannot be performed. On the other hand, in the method of accelerating the charge / discharge cycle test by making the amount of discharge electricity larger than the amount of charge electricity, the voltage at the end of the cycle is specified. Will be. However, since the increase in the internal resistance of the battery does not necessarily correspond to the remaining capacity, there arises a problem that the life of the battery cannot be accurately predicted.
この発明は、上述のような課題を解決するためになされたもので、電池内部での微小短絡がなく、電池の寿命を正確に早期予測できる電池あるいは電極の試験方法を提供するものである。   The present invention has been made in order to solve the above-described problems, and provides a battery or electrode test method capable of accurately and quickly predicting the battery life without a micro short circuit inside the battery.
この発明に係る電池の試験方法においては、電池の初期電池容量を測定する初期電池容量測定工程と、電池を1.5C以上の電流レートで上限電圧まで定電流充電する第1ステップ、この第1ステップの後に上限電圧を維持して所定の電流値に減ずるまで定電圧充電を継続する第2ステップ、この第2ステップの後に電池を1.5C以上の電流レートで所定の電圧まで定電流放電する第3ステップ、この第3ステップの後に前記電池を0.5C以下の電流レートで下限電圧まで定電流放電する第4ステップを繰り返す充放電サイクル工程と、この充放電サイクル工程を所定の回数繰り返した後に電池の維持電池容量を測定し、初期電池容量と維持電池容量とを比較して充放電サイクル工程に戻るか否かを判断する維持電池容量判定工程と、充放電サイクル工程の繰り返し回数および経過時間から電池の劣化を判断する劣化診断工程とを有するものである。   In the battery testing method according to the present invention, an initial battery capacity measuring step of measuring an initial battery capacity of the battery, a first step of charging the battery at a constant current to an upper limit voltage at a current rate of 1.5 C or more, the first step After the step, the second step of maintaining the upper limit voltage and continuing constant voltage charging until the current value is reduced to a predetermined current value. After this second step, the battery is discharged at a constant current to a predetermined voltage at a current rate of 1.5 C or more. 3rd step, after this 3rd step, charging / discharging cycle process which repeats the 4th step which carries out constant current discharge to the minimum voltage at the current rate of 0.5C or less, and this charging / discharging cycle process was repeated predetermined times A maintenance battery capacity determination step for measuring the maintenance battery capacity of the battery later, comparing the initial battery capacity with the maintenance battery capacity, and determining whether or not to return to the charge / discharge cycle process; Those having a degradation diagnostic process for determining the deterioration of the battery from the number of repetitions and the elapsed time of the electrodeposition cycle process.
この発明は、電池を1.5C以上の電流レートで充電する第1ステップ、この第1ステップの後に1.5C以上の電流レートで所定の維持電圧まで放電する第2ステップ、およびこの第2ステップの後に0.5C以下の電流レートで放電する第3ステップを繰り返す充放電サイクル工程を備えているので、高温環境で電池の充放電サイクルを行う必要がなく、微小短絡もなく、電池の寿命を正確に早期予測できる。   The present invention includes a first step of charging the battery at a current rate of 1.5 C or higher, a second step of discharging to a predetermined sustain voltage at a current rate of 1.5 C or higher after the first step, and the second step. Is equipped with a charge / discharge cycle process that repeats the third step of discharging at a current rate of 0.5 C or less after that, so there is no need to perform a charge / discharge cycle of the battery in a high temperature environment, there is no micro short circuit, and the life of the battery is reduced. Accurate early prediction.
実施の形態1.
図1は、この発明を実施するための実施の形態1における二次電池の断面模式図である。図1に示す二次電池はリチウムイオン電池であり、封止容器1の中に、セパレータ2を介して一方の面に正極3が他方の面に負極4が密着して形成された電池体5が周りを電解液6で充填された状態で密封配置されている。正極3および負極4からは、封止容器1と電気的に絶縁された電極端子(図示せず)を介して封止容器1の外部に電気的に引き出されている。封止容器1は、例えばアルミラミネートを用いることができる。セパレータ2としては、例えばポリエチレン製やポリプロピレン製の微多孔質膜などを用いることができる。正極3としては、活物質としてのコバルト酸リチウムなどの遷移金属酸化物と導電剤としてのカーボンとをポリフッ化ビニリデンなどの結着剤で結着させた多孔質体を集電体上に形成したものを用いることができる。また、負極4としては、1種類以上のカーボンを結着剤で結着させた多孔質体を集電体上に形成したものを用いることができる。電解液としては、例えばエチレンカーボネートとジエチルカーボネートとの混合溶媒に6フッ化リン酸リチウムなどの塩を溶解したものを用いることができる。なお、図1においては、電池体5は単層のコイン型のものを示しているが、実際には電池体を積層した構造や、帯状の電池体を扁平に巻回した構造が用いられる場合が多い。巻回した構造によって、電池容量を大きくすることができる。本実施の形態においては、電池容量が600mAhの設計容量をもつ電池を使用した。
Embodiment 1 FIG.
FIG. 1 is a schematic cross-sectional view of a secondary battery according to Embodiment 1 for carrying out the present invention. The secondary battery shown in FIG. 1 is a lithium ion battery, and a battery body 5 in which a positive electrode 3 and a negative electrode 4 are in close contact with each other in a sealed container 1 with a separator 2 interposed therebetween. Is hermetically arranged with the periphery filled with the electrolytic solution 6. The positive electrode 3 and the negative electrode 4 are electrically drawn out of the sealing container 1 via electrode terminals (not shown) that are electrically insulated from the sealing container 1. For example, an aluminum laminate can be used for the sealing container 1. As the separator 2, for example, a microporous film made of polyethylene or polypropylene can be used. As the positive electrode 3, a porous body in which a transition metal oxide such as lithium cobaltate as an active material and carbon as a conductive agent were bound with a binder such as polyvinylidene fluoride was formed on a current collector. Things can be used. Moreover, as the negative electrode 4, a porous body in which one or more kinds of carbons are bound with a binder and formed on a current collector can be used. As the electrolytic solution, for example, a solution obtained by dissolving a salt such as lithium hexafluorophosphate in a mixed solvent of ethylene carbonate and diethyl carbonate can be used. In FIG. 1, the battery body 5 is a single-layer coin type, but actually, a structure in which battery bodies are stacked or a structure in which a belt-like battery body is wound flat is used. There are many. The battery capacity can be increased by the wound structure. In the present embodiment, a battery having a design capacity of 600 mAh is used.
図2は、本実施の形態の電池の試験方法を示す構成図である。恒温装置7の中に測定対象となる電池8が設置されている。この電池8は、恒温装置7の外部に置かれた充放電用電源負荷装置9に電気的に接続されている。充放電用電源負荷装置9は、この充放電用電源負荷装置9に接続された制御装置10によって制御されている。充放電用電源負荷装置は、電圧計測部、電流計測部、充電器および負荷を内部に備えており、電池8を充電するときは、充電器から電池8に電圧を印加して充電を行い、そのときの充電電圧および電流を電圧計測部および電流計測部でそれぞれ計測している。電池8を放電するときは、電池8に負荷を接続して放電を行い、そのときの放電電圧および電流を電圧計測部および電流計測部でそれぞれ計測している。また、充放電時の電池容量は、計測された電圧および電流から求めることができる。制御装置10は、充放電用電源負荷装置9の充放電の繰り返し(充放電サイクル)や充放電時の電圧、電流などを制御している。   FIG. 2 is a configuration diagram showing a battery testing method of the present embodiment. A battery 8 to be measured is installed in the thermostatic device 7. The battery 8 is electrically connected to a charging / discharging power load device 9 placed outside the constant temperature device 7. The charging / discharging power load device 9 is controlled by a control device 10 connected to the charging / discharging power load device 9. The charging / discharging power load device includes a voltage measurement unit, a current measurement unit, a charger, and a load. When charging the battery 8, the battery 8 is charged by applying a voltage to the battery 8, The charging voltage and current at that time are measured by the voltage measuring unit and the current measuring unit, respectively. When discharging the battery 8, a load is connected to the battery 8 for discharging, and the discharge voltage and current at that time are measured by the voltage measuring unit and the current measuring unit, respectively. Moreover, the battery capacity at the time of charging / discharging can be calculated | required from the measured voltage and electric current. The control device 10 controls the charging / discharging repetition (charging / discharging cycle) of the charging / discharging power load device 9 and the voltage and current during charging / discharging.
本実施の形態においては、正極活物質としてLiCoO、負極活物質としてグラファイトを用いた扁平巻回型構造のリチウムイオン電池を用いた。このリチウムイオン電池の設計電池容量は600mAhである。電池の全容量を1時間で放電させるとだけの電流量は1Cと定義されており、したがって、この電池の1Cは、600mAに相当する。 In the present embodiment, a flat wound type lithium ion battery using LiCoO 2 as a positive electrode active material and graphite as a negative electrode active material was used. The design battery capacity of this lithium ion battery is 600 mAh. The amount of current required to discharge the entire capacity of the battery in 1 hour is defined as 1C. Therefore, 1C of this battery corresponds to 600 mA.
実施例1.
図3は、本実施の形態における実施例1の試験方法を説明する工程図である。まず始めに、初期電池容量を測定した。リチウムイオン電池を放電状態で恒温装置内の25℃の環境温度のもとに設置し、充放電用電源負荷装置から600mAの一定電流で上限電圧4.2Vまで充電した。その後300mAの一定電流で2.75Vまで放電させたときの放電容量を初期電池容量とした。
Example 1.
FIG. 3 is a process diagram for explaining the test method of Example 1 in the present embodiment. First, the initial battery capacity was measured. The lithium ion battery was placed in a discharged state at an ambient temperature of 25 ° C. in a constant temperature device, and charged to a maximum voltage of 4.2 V with a constant current of 600 mA from a charging / discharging power load device. Thereafter, the discharge capacity when discharged to 2.75 V at a constant current of 300 mA was defined as the initial battery capacity.
次に、充放電サイクルを行った。充放電用電源負荷装置から1200mA(2Cに相当)の定電流で上限電圧4.2Vまで充電を行った(定電流充電:第1ステップ)。さらに、電圧が4.2Vの一定を保つように充電電流を制御して充電を継続し(定電圧充電)、充電電流が50mAになった時点で充電を終了した(第2ステップ)。次に、充放電用電源負荷装置で1200mA(2Cに相当)の一定電流で電圧が2.75Vの下限電圧になるまで放電させた(定電流放電:第3ステップ)。つぎのステップとして、600mA(1Cに相当)の一定電流で、下限電圧(2.75V)まで再び定電流放電を行った(第4ステップ)。さらに次のステップとして、300mA(0.5Cに相当)の一定電流で、下限電圧(2.75V)まで再び定電流放電を行った(第5ステップ)。上述のような、定電流−定電圧充電および定電流放電(第1ステップから第5ステップ)を1つの充放電サイクルとして、この充放電サイクルを繰り返した。   Next, a charge / discharge cycle was performed. The charging / discharging power load device was charged to a maximum voltage of 4.2 V with a constant current of 1200 mA (corresponding to 2C) (constant current charging: first step). Furthermore, the charging current was controlled so that the voltage was kept constant at 4.2 V and charging was continued (constant voltage charging), and the charging was terminated when the charging current reached 50 mA (second step). Next, the battery was discharged at a constant current of 1200 mA (corresponding to 2C) with a charging / discharging power load device until the voltage reached a lower limit voltage of 2.75 V (constant current discharge: third step). As the next step, constant current discharge was performed again at a constant current of 600 mA (corresponding to 1 C) up to the lower limit voltage (2.75 V) (fourth step). Further, as a next step, constant current discharge was performed again at a constant current of 300 mA (corresponding to 0.5 C) to the lower limit voltage (2.75 V) (fifth step). The charge / discharge cycle was repeated with constant current-constant voltage charge and constant current discharge (from the first step to the fifth step) as described above as one charge / discharge cycle.
上述の充放電サイクルを所定の回数、例えば100回毎に、維持電池容量を測定した。測定方法は初期電池容量を測定した方法と同じである。維持電池容量が、初期電池容量の50%近くまで低下したところで維持電池容量を測定する頻度を増やした。その結果、維持電池容量が292mAh(初期電池容量の50%以下)になった時点での充放電サイクルは886サイクルであり、総試験時間は1589時間であった。   The above-mentioned charge / discharge cycle was measured a predetermined number of times, for example, every 100 times, and the maintenance battery capacity was measured. The measuring method is the same as the method of measuring the initial battery capacity. When the maintenance battery capacity was reduced to nearly 50% of the initial battery capacity, the frequency of measuring the maintenance battery capacity was increased. As a result, the charge / discharge cycle at the time when the maintenance battery capacity reached 292 mAh (50% or less of the initial battery capacity) was 886 cycles, and the total test time was 1589 hours.
比較例1.
実施例1と同様の初期電池容量をもつリチウムイオン電池を用いて、比較のための充放電サイクルを行った。比較例1は、実施例1と異なり、温度、充放電電流および充放電電気量を変えて充放電試験を行ったものである。まず始めに、実施例1と同様に恒温装置内の25℃の環境温度下で、初期電池容量を測定した。次に、比較のための充放電サイクルを行った。恒温装置内を50℃の環境温度とし、600mA(1Cに相当)の定電流で上限電圧4.2Vまで充電を行った(定電流充電)。さらに、電圧が4.2Vの一定を保つように充電電流を制御して充電を継続し(定電圧充電)、充電電流が50mAになった時点で充電を終了した。その後、300mA(0.5Cに相当)の定電流で6分間放電を行った。このような充放電の繰り返しを比較のための充放電サイクルとした。
Comparative Example 1
Using a lithium ion battery having the same initial battery capacity as in Example 1, a charge / discharge cycle for comparison was performed. Unlike Example 1, Comparative Example 1 is a charge / discharge test performed by changing the temperature, charge / discharge current, and charge / discharge electricity amount. First, in the same manner as in Example 1, the initial battery capacity was measured at an environmental temperature of 25 ° C. in the thermostatic apparatus. Next, a charge / discharge cycle for comparison was performed. The inside of the thermostatic apparatus was set to an environmental temperature of 50 ° C., and charging was performed up to an upper limit voltage of 4.2 V with a constant current of 600 mA (corresponding to 1 C) (constant current charging). Furthermore, the charging current was controlled so that the voltage was kept constant at 4.2 V and the charging was continued (constant voltage charging), and the charging was terminated when the charging current reached 50 mA. Thereafter, discharging was performed at a constant current of 300 mA (corresponding to 0.5 C) for 6 minutes. Such charge / discharge cycles were taken as charge / discharge cycles for comparison.
比較のための充放電サイクルを行った後に、維持電池容量を測定した。測定方法は初期電池容量を測定した方法と同じである。維持電池容量が300mAh以下(初期電池容量の50%以下)になった時点での充放電サイクルは1243サイクルであり、総試験時間は4092時間であった。   After performing a charge / discharge cycle for comparison, the maintenance battery capacity was measured. The measuring method is the same as the method of measuring the initial battery capacity. The charge / discharge cycle at the time when the maintenance battery capacity was 300 mAh or less (50% or less of the initial battery capacity) was 1243 cycles, and the total test time was 4092 hours.
比較例2.
比較例1で行った比較のための充放電サイクルを恒温装置内の環境温度を25℃で行った。それ以外の試験方法は、比較例1と同様である。比較例2は、実施例1と異なり、充放電電流および充放電電気量を変えて充放電試験を行ったものである。維持電池容量が300mAh以下(初期電池容量の50%以下)になった時点での充放電サイクルは8204サイクルであり、総試験時間は8613時間であった。
比較例3.
実施例1と同様の初期電池容量をもつリチウムイオン電池を用いて、比較のための充放電サイクルを行った。比較例3は、実施例1と異なり、充電電流、放電電流を共に1Cとしての充放電試験を行ったものである。まず始めに、実施例1と同様に恒温装置内の25℃の環境温度下で、初期電池容量を測定した。次に、比較のための充放電サイクルを行った。恒温装置内を25℃の環境温度とし、600mA(1Cに相当)の定電流で上限電圧4.2Vまで充電を行った(定電流充電)。さらに、電圧が4.2Vの一定を保つように充電電流を制御して充電を継続し(定電圧充電)、充電電流が50mAになった時点で充電を終了した。その後、600mA(1Cに相当)の定電流で2.75Vまで定電流放電を行う充放電サイクルを繰り返した。
Comparative Example 2
The charge / discharge cycle for comparison performed in Comparative Example 1 was performed at an environmental temperature of 25 ° C. in the thermostatic apparatus. Other test methods are the same as those in Comparative Example 1. Comparative Example 2 differs from Example 1 in that a charge / discharge test was performed by changing the charge / discharge current and the charge / discharge electricity amount. The charge / discharge cycle at the time when the maintenance battery capacity became 300 mAh or less (50% or less of the initial battery capacity) was 8204 cycles, and the total test time was 8613 hours.
Comparative Example 3
Using a lithium ion battery having the same initial battery capacity as in Example 1, a charge / discharge cycle for comparison was performed. Comparative Example 3 differs from Example 1 in that a charge / discharge test was performed with both charging current and discharging current set to 1C. First, in the same manner as in Example 1, the initial battery capacity was measured at an environmental temperature of 25 ° C. in the thermostatic apparatus. Next, a charge / discharge cycle for comparison was performed. The inside of the thermostatic device was set to an environmental temperature of 25 ° C., and charging was performed up to an upper limit voltage of 4.2 V with a constant current of 600 mA (corresponding to 1 C) (constant current charging). Furthermore, the charging current was controlled so that the voltage was kept constant at 4.2 V and the charging was continued (constant voltage charging), and the charging was terminated when the charging current reached 50 mA. Then, the charge / discharge cycle which performs constant current discharge to 2.75 V with a constant current of 600 mA (corresponding to 1 C) was repeated.
所定の回数の充放電サイクルを行った後に、維持電池容量を測定した。測定方法は実施例1で行った初期電池容量を測定した方法と同じである。維持電池容量が300mAh以下(初期電池容量の50%以下)になった時点での充放電サイクルは1489サイクルであり、総試験時間は2978時間であった。   After performing a predetermined number of charge / discharge cycles, the maintenance battery capacity was measured. The measurement method is the same as the method of measuring the initial battery capacity performed in Example 1. The charge / discharge cycle at the time when the maintenance battery capacity was 300 mAh or less (50% or less of the initial battery capacity) was 1489 cycles, and the total test time was 2978 hours.
比較例4.
実施例1と同様の初期電池容量をもつリチウムイオン電池を用いて、比較のための充放電サイクルを行った。比較例4は、実施例1と異なり、充電電気量より放電電気量を大きくして充放電試験を行ったものである。まず始めに、実施例1と同様に恒温装置内の25℃の環境温度下で、初期電池容量を測定した。次に、比較のための充放電サイクルを行った。恒温装置内を25℃の環境温度とし、600mA(1Cに相当)の定電流で上限電圧4.2Vまで充電を行った(定電流充電)。さらに、電圧が4.2Vの一定を保つように充電電流を制御して充電を継続し(定電圧充電)、充電電流が50mAになった時点で充電を終了した。その後、100mA(0.17Cに相当)の定電流で3時間放電を行ったのち、100mAの定電流で2.5時間充電を行い、さらに100mAの定電流で2.55時間の放電を繰り返した。このように100mAで2.5時間充電を行い、100mAで2.55時間放電を行う充放電の繰り返しを比較のための充放電サイクルとした。
Comparative Example 4
Using a lithium ion battery having the same initial battery capacity as in Example 1, a charge / discharge cycle for comparison was performed. Comparative Example 4 differs from Example 1 in that a charge / discharge test was performed with a discharge electricity amount larger than a charge electricity amount. First, in the same manner as in Example 1, the initial battery capacity was measured at an environmental temperature of 25 ° C. in the thermostatic apparatus. Next, a charge / discharge cycle for comparison was performed. The inside of the thermostatic device was set to an environmental temperature of 25 ° C., and charging was performed up to an upper limit voltage of 4.2 V with a constant current of 600 mA (corresponding to 1 C) (constant current charging). Furthermore, the charging current was controlled so that the voltage was kept constant at 4.2 V and the charging was continued (constant voltage charging), and the charging was terminated when the charging current reached 50 mA. Thereafter, after discharging at a constant current of 100 mA (corresponding to 0.17 C) for 3 hours, charging was performed at a constant current of 100 mA for 2.5 hours, and discharging was further repeated at a constant current of 100 mA for 2.55 hours. . Thus, charging / discharging cycle for charging for 2.5 hours at 100 mA and discharging for 2.55 hours at 100 mA was used as a charge / discharge cycle for comparison.
所定の回数の充放電サイクルを行った後に、放電電圧を測定し、放電電圧が2.6Vになった時点で充放電を終了した。このときの充放電サイクルは128サイクルであり、動作時間は672時間に相当した。しかしながら、この時点で実施例1と同様の方法で維持電池容量を測定したところ、維持電池容量は300mAh以上であったため、再度比較のための充放電サイクルを繰り返し、維持電池容量を測定した。維持電池容量が300mAh以下(初期電池容量の50%以下)になった時点での充放電サイクルは447サイクルであり、総試験時間は2347時間であった。   After performing a predetermined number of charge / discharge cycles, the discharge voltage was measured, and the charge / discharge was terminated when the discharge voltage reached 2.6V. The charge / discharge cycle at this time was 128 cycles, and the operation time corresponded to 672 hours. However, when the maintenance battery capacity was measured by the same method as in Example 1 at this time, the maintenance battery capacity was 300 mAh or more. Therefore, the charge / discharge cycle for comparison was repeated again to measure the maintenance battery capacity. The charge / discharge cycle at the time when the maintenance battery capacity was 300 mAh or less (50% or less of the initial battery capacity) was 447 cycles, and the total test time was 2347 hours.
表1は、本実施の形態における実施例および比較例の総試験時間を示したものである。   Table 1 shows the total test time for the examples and comparative examples in the present embodiment.
表1からわかるように、電池容量が50%以下になるまでの総試験時間が、本実施の形態における実施例1で示した電池の試験方法を用いると大幅に短縮できることがわかる。このように、実施例1の総試験時間が他の比較例に比べて短い理由を以下に説明する。比較例1においては、環境温度を50℃に設定しているので、定電圧充電では充電電流が50mAに低下するまで定電圧充電を継続するが、電池内部で微小な短絡が発生した場合は、電流の低下に時間がかかるために1回の充放電サイクル時間が長くなるためである。比較例2〜4においては、環境温度は実施例1と同様に25℃であるので、微小短絡は発生しないが、定電流充電時の電流が600mA(1Cに相当)と小さいので、劣化の進行が遅くなるためである。   As can be seen from Table 1, it can be seen that the total test time until the battery capacity reaches 50% or less can be significantly shortened by using the battery test method shown in Example 1 of the present embodiment. Thus, the reason why the total test time of Example 1 is shorter than other comparative examples will be described below. In Comparative Example 1, since the environmental temperature is set to 50 ° C., constant voltage charging is continued until the charging current is reduced to 50 mA in constant voltage charging, but when a small short circuit occurs inside the battery, This is because it takes a long time to decrease the current, so that one charge / discharge cycle time becomes long. In Comparative Examples 2 to 4, since the environmental temperature is 25 ° C. as in Example 1, no short-circuit occurs, but the current during constant current charging is as small as 600 mA (corresponding to 1 C), and thus the progress of deterioration. This is because it becomes slow.
以上のことから、本実施の形態における実施例1の電池の試験方法は、環境温度を室温として、1.5C以上の定電流での充放電サイクルを行っているので、高温環境で電池の充放電サイクルを行う必要がなく、微小短絡もなく、電池の寿命を正確に早期予測できる。   From the above, since the battery test method of Example 1 in this embodiment performs the charge / discharge cycle at a constant current of 1.5 C or higher with the ambient temperature set to room temperature, the battery is charged in a high temperature environment. There is no need to perform a discharge cycle, and there is no micro short circuit, and the battery life can be accurately and early predicted.
なお、本実施の形態における実施例1では、定電流放電を第3ステップから第5ステップの3回行っているが、第5ステップにおける0.5C以下の電流レートで下限電圧まで定電流放電させることが重要であり、第4ステップの1.0C以下の電流レートで下限電圧まで定電流放電させるステップを省略することができる。ただし、この第4ステップを行うことで、劣化の進行が早くなるので、さらに短時間で電池の寿命を正確に早期予測できる。   In Example 1 of the present embodiment, constant current discharge is performed three times from the third step to the fifth step. However, constant current discharge is performed up to the lower limit voltage at a current rate of 0.5 C or less in the fifth step. It is important that the step of constant current discharge to the lower limit voltage at a current rate of 1.0 C or less in the fourth step can be omitted. However, by performing the fourth step, the progress of deterioration is accelerated, so that the battery life can be accurately and early predicted in a shorter time.
また、本実施の形態においては、充放電サイクルを100回毎に維持電池容量を測定しているが、測定対象となる電池によって維持電池容量を測定するタイミングは異なるので、適宜変更することが望ましい。また、充放電サイクルを行っているときに充放電電流や充放電電圧をモニターしておき、それらの電気特性が所定の値になったときに維持電池容量を測定してもよい。   Further, in the present embodiment, the maintenance battery capacity is measured every 100 charge / discharge cycles. However, the timing for measuring the maintenance battery capacity differs depending on the battery to be measured. . Further, the charge / discharge current and the charge / discharge voltage may be monitored during the charge / discharge cycle, and the maintenance battery capacity may be measured when the electrical characteristics reach a predetermined value.
実施の形態2.
実施の形態2においては、電池の寿命を早期に予測することによって、その電池に用いられた電極の寿命を試験するものである。
Embodiment 2. FIG.
In the second embodiment, the life of an electrode used in the battery is tested by predicting the life of the battery at an early stage.
実施例2.
正極活物質としてのコバルト酸リチウム(LiCoO)をバインダ(例えばポリフッ化ビニリデン(PVDF))および導電助剤(例えばアセチレンブラック)と共に分散媒(例えばノルマル−メチルピロリドン(以下NMPと略す))に分散させた正極活物質ペーストを得た。次に、上述の正極活物質ペーストを、集電体となる集電体基材(例えば所定の厚さを有するアルミニウム箔)上に塗布した。さらに、これを乾燥させた後、所定の温度でかつ所定の面圧でプレスして所望の厚さ(約100μm厚)を有する活物質層を形成し、18mm×18mmの大きさの電極を得た。この電極の端部にアルミニウム端子を超音波溶接して試験極とした。次に、25mm×25mmの大きさのニッケル製の網の表面に厚さ約60μmのリチウム金属箔を圧着し、このニッケル網の端部にニッケル端子をスポット溶接して対極とした。
Example 2
Lithium cobalt oxide (LiCoO 2 ) as a positive electrode active material is dispersed in a dispersion medium (eg, normal-methylpyrrolidone (hereinafter abbreviated as NMP)) together with a binder (eg, polyvinylidene fluoride (PVDF)) and a conductive additive (eg, acetylene black). A positive electrode active material paste was obtained. Next, the above-described positive electrode active material paste was applied on a current collector base material (for example, an aluminum foil having a predetermined thickness) to be a current collector. Furthermore, after drying this, it presses with predetermined | prescribed temperature and predetermined | prescribed surface pressure, forms the active material layer which has desired thickness (about 100 micrometers thickness), and obtains the electrode of a 18 mm x 18 mm magnitude | size. It was. An aluminum terminal was ultrasonically welded to the end of this electrode to obtain a test electrode. Next, a lithium metal foil having a thickness of about 60 μm was pressure-bonded to the surface of a nickel mesh having a size of 25 mm × 25 mm, and a nickel terminal was spot-welded to the end of the nickel mesh to obtain a counter electrode.
このようにして得られた試験極と対極とを例えば多孔性のポリプロピレンシートを挟んで対向させることで、正極(試験極)と負極(対極)とを備えた電池体を得ることができる。この電池体をアルミラミネートシートを用いて作製された袋に入れ、例えばエチレンカーボネートおよびジエチルカーボネートの混合液(モル比=1:1)に6フッ化リン酸リチウムを濃度1.0mol/dmで溶解した電解液を注入したのち、正極のアルミ端子および負極のニッケル端子の端部が外部に露出するようにアルミラミネートシートの開口部を熱融着などで封口して電池を作製した。なお、正極のアルミ端子および負極のニッケル端子はアルミラミネートシートとは電気的に絶縁されている。 Thus, the battery body provided with the positive electrode (test electrode) and the negative electrode (counter electrode) can be obtained by making the obtained test electrode and counter electrode face each other with a porous polypropylene sheet interposed therebetween, for example. This battery body is put in a bag made of an aluminum laminate sheet, and, for example, lithium hexafluorophosphate is mixed at a concentration of 1.0 mol / dm 3 in a mixed solution of ethylene carbonate and diethyl carbonate (molar ratio = 1: 1). After injecting the dissolved electrolyte, the opening of the aluminum laminate sheet was sealed by heat sealing or the like so that the ends of the positive aluminum terminal and the negative nickel terminal were exposed to the outside. The positive aluminum terminal and the negative nickel terminal are electrically insulated from the aluminum laminate sheet.
このようにして作製した電池に対して、実施の形態1と同様な試験を行った。この電池の正極(試験極)の設計容量は6mAhである。実施の形態1と同様に、この電池を環境温度25℃の恒温装置の内部に設置し、充放電用電源負荷装置に接続した。   A test similar to that of Embodiment 1 was performed on the battery thus manufactured. The design capacity of the positive electrode (test electrode) of this battery is 6 mAh. In the same manner as in the first embodiment, this battery was installed inside a thermostatic device having an environmental temperature of 25 ° C. and connected to a charging / discharging power load device.
まず始めに、初期電池容量を測定した。電池を放電状態(正極と負極との電位差がない状態)で、充放電用電源負荷装置から6mAの一定電流で上限電圧4.2Vまで充電した。その後3mAの一定電流で2.75Vまで放電させたときの放電容量を初期電池容量とした。   First, the initial battery capacity was measured. The battery was charged to a maximum voltage of 4.2 V at a constant current of 6 mA from a charging / discharging power load device in a discharged state (a state in which there is no potential difference between the positive electrode and the negative electrode). Thereafter, the discharge capacity when discharged to 2.75 V at a constant current of 3 mA was defined as the initial battery capacity.
次に、充放電サイクルを行った。充放電用電源負荷装置から12mA(2Cに相当)の定電流で上限電圧4.2Vまで充電を行った(定電流充電:第1ステップ)。さらに、電圧が4.2Vの一定を保つように充電電流を制御して充電を継続し(定電圧充電)、定電流充電と定電圧充電とを合わせて3時間経過後に充電を終了した(第2ステップ)。次に、充放電用電源負荷装置で12mA(2Cに相当)の一定電流で電圧が2.75Vの下限電圧になるまで放電させた(定電流放電:第3ステップ)。第3ステップ終了後に、電池を電気的に開放すると電池の電圧は再び上昇するので、つぎのステップとして、6mA(1Cに相当)の一定電流で、下限電圧(2.75V)まで再び定電流放電を行った(第4ステップ)。さらに次のステップとして、3mA(0.5Cに相当)の一定電流で、下限電圧(2.75V)まで再び定電流放電を行った(第5ステップ)。上述のような、定電流充電、定電圧充電および定電流放電(第1ステップから第5ステップ)を1つの充放電サイクルとして、この充放電サイクルを所定の回数繰り返した。   Next, a charge / discharge cycle was performed. Charging was performed from the charging / discharging power load device to a maximum voltage of 4.2 V with a constant current of 12 mA (corresponding to 2C) (constant current charging: first step). Further, the charging current is controlled so that the voltage is kept constant at 4.2 V (continuous charging), and the charging is terminated after 3 hours in combination with the constant current charging and the constant voltage charging. 2 steps). Next, the battery was discharged at a constant current of 12 mA (corresponding to 2C) with a charging / discharging power load device until the voltage reached a lower limit voltage of 2.75 V (constant current discharge: third step). When the battery is electrically opened after the third step, the battery voltage rises again, so the next step is constant current discharge again at a constant current of 6 mA (corresponding to 1 C) up to the lower limit voltage (2.75 V). (4th step). Further, as a next step, constant current discharge was performed again at a constant current of 3 mA (corresponding to 0.5 C) up to the lower limit voltage (2.75 V) (fifth step). The above-described constant current charging, constant voltage charging and constant current discharging (from the first step to the fifth step) were taken as one charging / discharging cycle, and this charging / discharging cycle was repeated a predetermined number of times.
所定の回数の充放電サイクルを行った後に、維持電池容量を測定した。測定方法は初期電池容量を測定した方法と同じである。維持電池容量が2.7mAh(初期電池容量の約45%)になった時点での充放電サイクルは289サイクルであり、総試験時間は498時間であった。   After performing a predetermined number of charge / discharge cycles, the maintenance battery capacity was measured. The measuring method is the same as the method of measuring the initial battery capacity. The charge / discharge cycle at the time when the maintenance battery capacity reached 2.7 mAh (about 45% of the initial battery capacity) was 289 cycles, and the total test time was 498 hours.
比較例5.
実施例2と同様の初期電池容量をもつ電池を用いて、比較のための充放電サイクルを行った。比較例5は、実施例2と異なり、実施例2の放電ステップを第3ステップのみとしたものである。まず始めに、実施例1と同様に恒温装置内の25℃の環境温度下で、初期電池容量を測定した。次に、比較のための充放電サイクルを行った。25℃の環境温度のもとで、12mA(2Cに相当)の定電流で上限電圧4.2Vまで充電を行った(定電流充電)。さらに、電圧が4.2Vの一定を保つように充電電流を制御して充電を継続し(定電圧充電)、定電流充電と定電圧充電とを合わせて3時間経過後に充電を終了した。その後、12mA(2Cに相当)の定電流で下限電圧2.7Vまで放電を行った(定電流放電)。このような充放電の繰り返しを比較のための充放電サイクルとした。
Comparative Example 5
Using a battery having the same initial battery capacity as in Example 2, a charge / discharge cycle for comparison was performed. Comparative Example 5 differs from Example 2 in that the discharge step of Example 2 is only the third step. First, in the same manner as in Example 1, the initial battery capacity was measured at an environmental temperature of 25 ° C. in the thermostatic apparatus. Next, a charge / discharge cycle for comparison was performed. Under an ambient temperature of 25 ° C., the battery was charged to a maximum voltage of 4.2 V with a constant current of 12 mA (corresponding to 2C) (constant current charging). Furthermore, the charging current was controlled so that the voltage was kept constant at 4.2 V and charging was continued (constant voltage charging), and the charging was terminated after the lapse of 3 hours by combining the constant current charging and the constant voltage charging. Thereafter, the battery was discharged to a lower limit voltage of 2.7 V with a constant current of 12 mA (corresponding to 2C) (constant current discharge). Such charge / discharge cycles were taken as charge / discharge cycles for comparison.
所定の回数の比較のための充放電サイクルを行った後に、維持電池容量を測定した。測定方法は、再度同じ条件で定電流充電と定電圧充電を行った後に、3mAの定電流で下限電圧2.75Vまで定電流放電を行ったときの放電容量を維持電池容量とした。
維持電池容量が2.9mAh(初期電池容量の約48%)になった時点での充放電サイクルは376サイクルであり、総試験時間は630時間であった。
After performing a predetermined number of charge / discharge cycles for comparison, the maintenance battery capacity was measured. In the measurement method, after carrying out constant current charging and constant voltage charging again under the same conditions, the discharge capacity when carrying out constant current discharge to a lower limit voltage of 2.75 V at a constant current of 3 mA was defined as the maintenance battery capacity.
The charge / discharge cycle at the time when the maintenance battery capacity reached 2.9 mAh (about 48% of the initial battery capacity) was 376 cycles, and the total test time was 630 hours.
実施例2では、維持電池容量が初期電池容量の約45%に達するまでに498時間であるが、比較例5では、630時間経過しても維持電池容量は初期電池容量の約48%である。この理由は、実施例2では低レートでの放電(0.5C放電)によりDODが深い放電がなされているのに対して、比較例5では2C放電のみなので結果的にDODが浅い放電になっているからである。   In Example 2, it is 498 hours until the maintenance battery capacity reaches about 45% of the initial battery capacity, but in Comparative Example 5, the maintenance battery capacity is about 48% of the initial battery capacity even after 630 hours have passed. . The reason for this is that in Example 2, the discharge at a low rate (0.5 C discharge) caused a deep DOD discharge, whereas in Comparative Example 5, only a 2 C discharge was generated, resulting in a shallow DOD discharge. Because.
このように、本実施の形態のように室温程度の環境下で高レートかつDODの深い充放電サイクルを行っているので、高温環境や過電圧を印加で電池の充放電サイクルを行う必要がなく、微小短絡もなく、電極の寿命を正確に早期予測できる。   As described above, since a high rate and deep DOD charge / discharge cycle is performed in an environment of about room temperature as in the present embodiment, it is not necessary to perform a charge / discharge cycle of the battery by applying a high temperature environment or overvoltage, There is no short circuit, and the life of the electrode can be accurately and early predicted.
実施の形態3.
実施の形態3においては、充電電気量を試験対象となる電池の設計容量より大きくしたものである。
Embodiment 3 FIG.
In Embodiment 3, the amount of charge electricity is made larger than the design capacity of the battery to be tested.
実施の形態1における実施例1で用いた電池と同様な設計電池容量が600mAhのリチウムイオン電池において、環境温度25℃のもとで、充放電サイクルを行った。充放電用電源負荷装置から1200mA(2Cに相当)の定電流で上限電圧4.3Vまで充電を行った(定電流充電:第1ステップ)。さらに、電圧が4.3Vの一定を保つように充電電流を制御して充電を継続し(定電圧充電)、充電電流が50mAになった時点で充電を終了した(第2ステップ)。このときの充電電気量は、635mAhであった。   In a lithium ion battery having a designed battery capacity of 600 mAh similar to the battery used in Example 1 in Embodiment 1, a charge / discharge cycle was performed at an environmental temperature of 25 ° C. The charging / discharging power source load device was charged to a maximum voltage of 4.3 V with a constant current of 1200 mA (corresponding to 2C) (constant current charging: first step). Furthermore, the charging current was controlled so that the voltage was kept constant at 4.3 V and charging was continued (constant voltage charging), and the charging was terminated when the charging current reached 50 mA (second step). The amount of electricity charged at this time was 635 mAh.
次に、充放電用電源負荷装置で1200mA(2Cに相当)の一定電流で電圧が2.75Vの下限電圧になるまで放電させた(定電流放電:第3ステップ)。第3ステップ終了後に、電池を電気的に開放すると電池の電圧は再び上昇するので、つぎのステップとして、600mA(1Cに相当)の一定電流で、下限電圧(2.75V)まで再び定電流放電を行った(第4ステップ)。さらに次のステップとして、300mA(0.5Cに相当)の一定電流で、下限電圧(2.75V)まで再び定電流放電を行った(第5ステップ)。上述のような、定電流充電、定電圧充電および定電流放電(第1ステップから第5ステップ)を1つの充放電サイクルとして、この充放電サイクルを所定の回数繰り返した。   Next, the battery was discharged at a constant current of 1200 mA (corresponding to 2C) with a charging / discharging power load device until the voltage reached a lower limit voltage of 2.75 V (constant current discharge: third step). When the battery is electrically opened after the third step, the battery voltage rises again. Therefore, the next step is constant current discharge to a lower limit voltage (2.75 V) at a constant current of 600 mA (corresponding to 1 C). (4th step). Further, as a next step, constant current discharge was performed again at a constant current of 300 mA (corresponding to 0.5 C) to the lower limit voltage (2.75 V) (fifth step). The above-described constant current charging, constant voltage charging and constant current discharging (from the first step to the fifth step) were taken as one charging / discharging cycle, and this charging / discharging cycle was repeated a predetermined number of times.
所定の回数の充放電サイクルを行った後に、維持電池容量を測定した。測定方法は初期電池容量を測定した方法と同じである。維持電池容量が293mAh(初期電池容量の50%以下)になった時点での充放電サイクルは522サイクルであり、総試験時間は864時間であった。   After performing a predetermined number of charge / discharge cycles, the maintenance battery capacity was measured. The measuring method is the same as the method of measuring the initial battery capacity. The charge / discharge cycle at the time when the maintenance battery capacity was 293 mAh (50% or less of the initial battery capacity) was 522 cycles, and the total test time was 864 hours.
本実施の形態においては、充電電気量を設計電池容量より大きくしたことにより、高温環境で電池の充放電サイクルを行う必要がなく、微小短絡もなく、実施例1よりも短時間で電池の寿命を正確に早期予測できる。   In the present embodiment, since the amount of charged electricity is larger than the designed battery capacity, it is not necessary to perform a charge / discharge cycle of the battery in a high temperature environment, there is no short circuit, and the battery life is shorter than that of Example 1. Can be accurately and early predicted.
実施の形態4.
実施の形態4においては、円筒型構造のリチウムイオン電池において試験を行ったものである。また、環境温度を変化させて試験を行ったものである。
Embodiment 4 FIG.
In the fourth embodiment, a test was performed on a lithium ion battery having a cylindrical structure. Further, the test was performed by changing the environmental temperature.
実施例3.
正極活物質がLiCoO、負極活物質がグラファイトである円筒型構造のリチウムイオン電池(設計容量2000mAh)を使用した。この電池を25℃の環境温度のもとで、4000mA(2.0Cに相当)の一定電流で上限電圧4.2Vまで充電を行った(定電流充電:第1ステップ)。さらに、電圧が4.2Vの一定を保つように充電電流を制御して充電を継続し(定電圧充電)、充電電流が50mAになった時点で充電を終了した。
Example 3 FIG.
A cylindrical lithium ion battery (design capacity 2000 mAh) in which the positive electrode active material was LiCoO 2 and the negative electrode active material was graphite was used. The battery was charged to an upper limit voltage of 4.2 V at a constant current of 4000 mA (corresponding to 2.0 C) under an environmental temperature of 25 ° C. (constant current charging: first step). Furthermore, the charging current was controlled so that the voltage was kept constant at 4.2 V and the charging was continued (constant voltage charging), and the charging was terminated when the charging current reached 50 mA.
次に、充放電用電源負荷装置で4000mA(2Cに相当)の一定電流で電圧が2.75Vの下限電圧になるまで放電させた(定電流放電:第3ステップ)。第3ステップ終了後に、電池を電気的に開放すると電池の電圧は再び上昇するので、つぎのステップとして、2000mA(1Cに相当)の一定電流で、下限電圧(2.75V)まで再び定電流放電を行った(第4ステップ)。さらに次のステップとして、1000mA(0.5Cに相当)の一定電流で、下限電圧(2.75V)まで再び定電流放電を行った(第5ステップ)。上述のような、定電流充電、定電圧充電および定電流放電(第1ステップから第5ステップ)を1つの充放電サイクルとして、この充放電サイクルを所定の回数繰り返した。   Next, the battery was discharged at a constant current of 4000 mA (corresponding to 2C) until the voltage reached a lower limit voltage of 2.75 V with a charging / discharging power load device (constant current discharge: third step). When the battery is electrically opened after the third step, the battery voltage rises again. Therefore, the next step is constant current discharge to a lower limit voltage (2.75 V) at a constant current of 2000 mA (corresponding to 1 C). (4th step). Further, as a next step, constant current discharge was performed again at a constant current of 1000 mA (corresponding to 0.5 C) up to the lower limit voltage (2.75 V) (fifth step). The above-described constant current charging, constant voltage charging and constant current discharging (from the first step to the fifth step) were taken as one charging / discharging cycle, and this charging / discharging cycle was repeated a predetermined number of times.
維持電池容量の測定は、次のとおりである。充放電用電源負荷装置から1400mAの一定電流で上限電圧4.2Vまで充電した。その後1000mAの一定電流で2.75Vまで放電させたときの放電容量を維持電池容量とした。維持電池容量が982mAh(初期電池容量の50%以下)になった時点での充放電サイクルは703サイクルであり、総試験時間は1352時間であった。   The measurement of the maintenance battery capacity is as follows. The battery was charged from the charging / discharging power supply load device to an upper limit voltage of 4.2 V with a constant current of 1400 mA. Thereafter, the discharge capacity when discharged to 2.75 V at a constant current of 1000 mA was defined as the maintenance battery capacity. The charge / discharge cycle at the time when the maintenance battery capacity reached 982 mAh (50% or less of the initial battery capacity) was 703 cycles, and the total test time was 1352 hours.
比較例6.
実施例3と同じ試験を9℃環境温度のもとで行ったところ、維持電池容量が982mAh(初期電池容量の50%以下)になった時点での充放電サイクルは1029サイクルであり、総試験時間は1969時間であった。
Comparative Example 6
When the same test as in Example 3 was performed at an ambient temperature of 9 ° C., the charge / discharge cycle when the maintenance battery capacity reached 982 mAh (50% or less of the initial battery capacity) was 1029 cycles. The time was 1969 hours.
比較例7.
実施例3と同じ試験を52℃環境温度のもとで行ったところ、維持電池容量が982mAh(初期電池容量の50%以下)になった時点での充放電サイクルは827サイクルであり、総試験時間は1923時間であった。
Comparative Example 7
When the same test as in Example 3 was performed at an environmental temperature of 52 ° C., the charge / discharge cycle when the sustain battery capacity reached 982 mAh (50% or less of the initial battery capacity) was 827 cycles, and the total test The time was 1923 hours.
本実施の形態においては、環境温度が10℃より低い場合(比較例6)、電極劣化が進行せず、容量低下が遅く試験時間が長くなったと考えられる。一方、環境温度が50℃より高い場合(比較例7)、電池内部で微小な短絡が発生し、定電圧充電時の電流の低下に時間がかかるために1回の充放電サイクル時間が長くなるためと考えられる。したがって、本実施の形態の結果から、試験時の環境温度は、10℃以上50℃以下が好ましい。   In the present embodiment, when the environmental temperature is lower than 10 ° C. (Comparative Example 6), it is considered that the electrode deterioration did not proceed, the capacity reduction was slow, and the test time was long. On the other hand, when the environmental temperature is higher than 50 ° C. (Comparative Example 7), a minute short circuit occurs inside the battery, and it takes time to decrease the current during constant voltage charging, so one charge / discharge cycle time becomes long. This is probably because of this. Therefore, from the results of the present embodiment, the environmental temperature during the test is preferably 10 ° C. or higher and 50 ° C. or lower.
実施の形態5.
実施の形態5においては、実施の形態1の実施例1で示した試験方法において、上限電圧4.2Vまで充電を行う(定電流充電:第1ステップ)ときの電流レートを変化させたものである。それ以外の試験方法の各ステップは実施例1と同様である。試験に用いた電池は実施の形態1と同じものである。第1ステップの電流レートを、600mA(1.0Cに相当)、660mA(1.1C)、720mA(1.2C)、780mA(1.3C)、840mA(1.4C)、900mA(1.5C)、960mA(1.6C)、1020mA(1.7C)、1080mA(1.8C)、1140mA(1.9C)および1200mA(2C)と変化させて、充放電サイクルを行い、維持電気容量が初期電気容量の50%以下となったときの充放電サイクルの回数および総試験時間を計測した。
Embodiment 5 FIG.
In the fifth embodiment, in the test method shown in Example 1 of the first embodiment, the current rate when charging is performed up to the upper limit voltage of 4.2 V (constant current charging: first step) is changed. is there. The other steps of the test method are the same as in Example 1. The battery used for the test is the same as in the first embodiment. The current rate of the first step is 600 mA (corresponding to 1.0 C), 660 mA (1.1 C), 720 mA (1.2 C), 780 mA (1.3 C), 840 mA (1.4 C), 900 mA (1.5 C). ), 960 mA (1.6 C), 1020 mA (1.7 C), 1080 mA (1.8 C), 1140 mA (1.9 C), and 1200 mA (2 C), and a charge / discharge cycle is performed. The number of charge / discharge cycles and the total test time when the electric capacity was 50% or less were measured.
表2は、本実施の形態における、第1ステップの電流レートと総試験時間との関係を示したものである。なお、表2において、電流レートはCを用いて表している。   Table 2 shows the relationship between the current rate of the first step and the total test time in the present embodiment. In Table 2, the current rate is expressed using C.
この表からわかるように、第1ステップの電流レートが1.5C以上であれば、総試験時間が2000時間以下となり、第1ステップの電流レートがそれより小さい場合には、総試験時間が2000時間以上となって、長時間の試験時間が必要になることがわかる。このようなことから、第1ステップの電流レートが1.5C以上であれば、試験時間の大幅な短縮が可能となり、電池の寿命を正確に早期予測できる。   As can be seen from this table, if the current rate of the first step is 1.5C or more, the total test time is 2000 hours or less, and if the current rate of the first step is smaller than that, the total test time is 2000. It can be seen that the test time is longer and requires a long test time. For this reason, if the current rate in the first step is 1.5 C or more, the test time can be greatly shortened, and the battery life can be accurately and early predicted.
この発明の実施の形態1による電池の断面模式図である。1 is a schematic cross-sectional view of a battery according to Embodiment 1 of the present invention. この発明の実施の形態1による電池の試験方法を示す構成図である。It is a block diagram which shows the test method of the battery by Embodiment 1 of this invention. この発明の実施の形態1による試験方法を説明する工程図である。It is process drawing explaining the test method by Embodiment 1 of this invention.
符号の説明Explanation of symbols
1:封止容器
2:セパレータ
3:正極
4:負極
5:電池体
6:電解液
7:恒温装置
8:電池
9:充放電用電源負荷装置
10:制御装置
1: Sealing container 2: Separator 3: Positive electrode 4: Negative electrode 5: Battery body 6: Electrolyte 7: Constant temperature device 8: Battery 9: Power load device 10 for charging / discharging: Control device

Claims (6)

  1. 電池の初期電池容量を測定する初期電池容量測定工程と、
    前記電池を1.5C以上の電流レートで上限電圧まで定電流充電する第1ステップ、
    この第1ステップの後に前記上限電圧を維持して所定の電流値に減ずるまで定電圧充電を継続する第2ステップ、
    この第2ステップの後に前記電池を1.5C以上の電流レートで所定の電圧まで定電流放電する第3ステップ、
    この第3ステップの後に前記電池を0.5C以下の電流レートで下限電圧まで定電流放電する第4ステップ
    を繰り返す充放電サイクル工程と、
    この充放電サイクル工程を所定の回数繰り返した後に前記電池の維持電池容量を測定し、前記初期電池容量と前記維持電池容量とを比較して前記充放電サイクル工程に戻るか否かを判断する維持電池容量判定工程と、
    前記充放電サイクル工程の繰り返し回数および経過時間から前記電池の劣化を判断する劣化診断工程と
    を有する電池の試験方法。
    An initial battery capacity measurement step for measuring the initial battery capacity of the battery;
    A first step of constant-current charging the battery to an upper limit voltage at a current rate of 1.5 C or higher;
    A second step in which constant voltage charging is continued until the upper limit voltage is maintained and the current value is reduced to a predetermined current value after the first step;
    After this second step, a third step of discharging the battery at a constant current to a predetermined voltage at a current rate of 1.5 C or higher,
    A charge / discharge cycle step of repeating a fourth step of discharging the battery at a current rate of 0.5 C or less to a lower limit voltage after the third step;
    The maintenance battery capacity of the battery is measured after repeating this charge / discharge cycle process a predetermined number of times, and the initial battery capacity is compared with the sustain battery capacity to determine whether to return to the charge / discharge cycle process. Battery capacity determination step;
    A battery testing method comprising: a deterioration diagnosis step of determining deterioration of the battery from the number of repetitions and elapsed time of the charge / discharge cycle step.
  2. 第1ステップの充電電気量を、電池の設計容量より大きくしたことを特徴とする請求項1記載の電池の試験方法。 2. The battery test method according to claim 1, wherein the amount of charge in the first step is larger than the design capacity of the battery.
  3. 環境温度を、10℃以上50℃以下としたことを特徴とする請求項1記載の電池の試験方法。 2. The battery testing method according to claim 1, wherein the environmental temperature is 10 [deg.] C. or more and 50 [deg.] C. or less.
  4. セパレータと、このセパレータを挟んで対向する一対の電極と、この電極および前記セパレータに含浸された電解質を含んだ電解液とを含む電池を構成し、
    前記電池の初期電池容量を測定する初期電池容量測定工程と、
    前記電池を1.5C以上の電流レートで上限電圧まで定電流充電する第1ステップ、
    この第1ステップの後に前記上限電圧を維持して所定の電流値に減ずるまで定電圧充電を継続する第2ステップ、
    この第2ステップの後に前記電池を1.5C以上の電流レートで所定の電圧まで定電流放電する第3ステップ、
    この第3ステップの後に前記電池を0.5C以下の電流レートで下限電圧まで定電流放電する第4ステップ
    を繰り返す充放電サイクル工程と、
    この充放電サイクル工程を所定の回数繰り返した後に前記電池の維持電池容量を測定し、前記初期電池容量と前記維持電池容量とを比較して前記充放電サイクル工程に戻るか否かを判断する維持電池容量判定工程と、
    前記充放電サイクル工程の繰り返し回数および経過時間から前記電極の劣化を判断する劣化診断工程と
    を有する電極の試験方法。
    A battery comprising a separator, a pair of electrodes facing each other with the separator interposed therebetween, and an electrolyte containing the electrolyte impregnated in the electrode and the separator,
    An initial battery capacity measuring step for measuring an initial battery capacity of the battery;
    A first step of constant-current charging the battery to an upper limit voltage at a current rate of 1.5 C or higher;
    A second step in which constant voltage charging is continued until the upper limit voltage is maintained and the current value is reduced to a predetermined current value after the first step;
    After this second step, a third step of discharging the battery at a constant current to a predetermined voltage at a current rate of 1.5 C or higher,
    A charge / discharge cycle step of repeating a fourth step of discharging the battery at a current rate of 0.5 C or less to a lower limit voltage after the third step;
    The maintenance battery capacity of the battery is measured after repeating this charge / discharge cycle process a predetermined number of times, and the initial battery capacity is compared with the sustain battery capacity to determine whether to return to the charge / discharge cycle process. Battery capacity determination step;
    An electrode test method comprising: a deterioration diagnosis step of determining deterioration of the electrode from the number of repetitions and elapsed time of the charge / discharge cycle step.
  5. 第1ステップの充電電気量を、電池の設計容量より大きくしたことを特徴とする請求項4記載の電極の試験方法。 5. The electrode testing method according to claim 4, wherein the amount of charge in the first step is larger than the design capacity of the battery.
  6. 環境温度を、10℃以上50℃以下としたことを特徴とする請求項4記載の電極の試験方法。 5. The method for testing an electrode according to claim 4, wherein the environmental temperature is 10 ° C. or higher and 50 ° C. or lower.
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