JP6308145B2 - Secondary battery inspection method - Google Patents
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- JP6308145B2 JP6308145B2 JP2015039177A JP2015039177A JP6308145B2 JP 6308145 B2 JP6308145 B2 JP 6308145B2 JP 2015039177 A JP2015039177 A JP 2015039177A JP 2015039177 A JP2015039177 A JP 2015039177A JP 6308145 B2 JP6308145 B2 JP 6308145B2
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
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Description
本発明は、二次電池の検査方法に関し、例えば、低温出力を保証するための低温出力検査を有する二次電池の検査方法に関する。 The present invention relates to a secondary battery inspection method, for example, a secondary battery inspection method having a low temperature output inspection for guaranteeing a low temperature output.
二次電池の検査工程では、二次電池が低温環境下に置かれた場合の出力能力を保証するための低温出力検査がある。特許文献１では、二次電池の充電率（ＳＯＣ：State Of Charge）を３〜１５％に設定するステップと、１０℃〜３０℃の環境下においてＳＯＣが３〜１５％の二次電池の抵抗を測定するステップとを有する。また、特許文献１に記載の技術では、エージング工程の後に測定ステップを行い、当該測定ステップの測定結果に基づき低温出力検査を行う。
In the inspection process of the secondary battery, there is a low temperature output inspection for guaranteeing the output capability when the secondary battery is placed in a low temperature environment. In
しかしながら、エージング工程の後に低温出力検査を行った場合、ＳＥＩ被膜の形成反応が完了した後の電圧降下量を元に低温出力検査を行うため、測定される二次電池の抵抗（例えば、反応抵抗）が小さく、測定精度を十分に確保出来ない問題がある。 However, when the low-temperature output inspection is performed after the aging process, the low-temperature output inspection is performed based on the amount of voltage drop after the SEI film formation reaction is completed. ) Is small, and there is a problem that sufficient measurement accuracy cannot be secured.
本発明は、上記事情に鑑みてなされたものであり、低温出力検査の精度を向上させることを目的とするものである。 The present invention has been made in view of the above circumstances, and aims to improve the accuracy of low-temperature output inspection.
本発明にかかる二次電池の検査方法の一態様は、二次電池の検査方法であって、検査対象セルを予め定められた所定の電圧まで充電する充電工程と、前記所定の電圧以下の電圧で放電を行い、前記放電の前後の電圧降下量を算出する電圧降下量算出工程と、前記電圧降下量が閾値以下である場合に良品と判定する良品判定工程と、前記良品判定工程後にエージングを行うエージング工程と、を有する。 One aspect of the inspection method for a secondary battery according to the present invention is a method for inspecting a secondary battery, a charging step of charging a cell to be inspected to a predetermined voltage, and a voltage equal to or lower than the predetermined voltage. A voltage drop amount calculating step for calculating a voltage drop amount before and after the discharge, a non-defective product determining step for determining a non-defective product when the voltage drop amount is equal to or less than a threshold value, and aging after the non-defective product determining step. An aging step to be performed.
本発明にかかる二次電池の検査方法では、エージング工程を行う前に二次電池を放電させたときの電圧降下量を測定し、当該測定結果に基づき低温出力検査を行う。これにより、本発明にかかる二次電池の検査方法では、ＳＥＩ被膜の形成反応が完了する前の電圧降下量をもとに低温出力検査を行うため、測定される反応抵抗が大きくなり、二次電池の反応抵抗と低温出力との相関を高くすることができる。 In the inspection method of the secondary battery according to the present invention, the amount of voltage drop when the secondary battery is discharged is measured before the aging process is performed, and the low temperature output inspection is performed based on the measurement result. Thereby, in the inspection method of the secondary battery according to the present invention, since the low temperature output inspection is performed based on the voltage drop amount before the formation reaction of the SEI film is completed, the measured reaction resistance increases, The correlation between the battery reaction resistance and the low-temperature output can be increased.
本発明にかかる二次電池の検査方法によれば、低温出力検査の測定精度を向上させることができる。 According to the secondary battery inspection method of the present invention, the measurement accuracy of the low-temperature output inspection can be improved.
以下、図面を参照して本発明の実施の形態について説明する。説明の明確化のため、以下の記載及び図面は、適宜、省略、及び簡略化がなされている。各図面において、同一の要素には同一の符号が付されており、必要に応じて重複説明は省略されている。 Embodiments of the present invention will be described below with reference to the drawings. For clarity of explanation, the following description and drawings are omitted and simplified as appropriate. In the drawings, the same elements are denoted by the same reference numerals, and redundant description is omitted as necessary.
実施の形態１にかかる二次電池の検査方法において、検査対象とする二次電池は、例えば、リチウムイオン電池である。そこで、以下の説明では、検査する二次電池は、リチウムイオン電池であるものとして説明を行う。 In the secondary battery inspection method according to the first embodiment, the secondary battery to be inspected is, for example, a lithium ion battery. Therefore, in the following description, the secondary battery to be inspected is described as being a lithium ion battery.
図１に実施の形態１にかかる二次電池の検査方法のフローチャートを示す。図１に示すように、実施の形態１にかかる二次電池の検査方法では、まず、検査対象セル（例えば、二次電池）の電圧が予め定められた所定の電圧（以下の説明では、測定電圧と称す）になるまで二次電池を充電する充電工程Ｓ１を行う。この測定電圧は、二次電池の低温出力と後述する低温出力特性検査工程Ｓ２における電圧降下量との相関係数が０．８以上となる二次電池の電圧、又は、二次電池の低温出力と低温出力特性検査工程Ｓ２における電圧降下量との相関係数が０．７以上となる二次電池の充電率に基づき決定される。 FIG. 1 is a flowchart of a secondary battery inspection method according to the first embodiment. As shown in FIG. 1, in the secondary battery inspection method according to the first embodiment, first, a voltage of an inspection target cell (for example, a secondary battery) is set to a predetermined voltage (in the following description, measured) A charging step S1 for charging the secondary battery is performed until the voltage reaches a voltage. This measured voltage is the voltage of the secondary battery at which the correlation coefficient between the low temperature output of the secondary battery and the voltage drop amount in the low temperature output characteristic inspection step S2 described later is 0.8 or the low temperature output of the secondary battery. And the charging rate of the secondary battery in which the correlation coefficient between the voltage drop amount in the low temperature output characteristic inspection step S2 is 0.7 or more.
次いで、実施の形態１にかかる二次電池の検査方法では、低温出力特性の検査を行う低温出力特性検査工程Ｓ２を行う。この低温出力特性検査工程Ｓ２では、まず、測定電圧以下の電圧で二次電池を放電させ、放電の前後の電圧降下量を算出する電圧降下量算出工程が含まれる。また、低温出力特性検査工程Ｓ２における放電工程では、定電流による放電を行う。低温出力特性検査工程Ｓ２では、放電に利用した定電流の大きさと放電の前後の電圧降下量とに基づき二次電池の反応抵抗を算出することができる。しかしながら、実施の形態１にかかる二次電池の検査方法では、放電に用いる定電流の大きさが予め決められているため、電圧降下量のみで後述する良品判定を行う。 Next, in the secondary battery inspection method according to the first embodiment, a low-temperature output characteristic inspection step S <b> 2 for performing inspection of low-temperature output characteristics is performed. The low temperature output characteristic inspection step S2 includes a voltage drop amount calculating step of first discharging the secondary battery at a voltage equal to or lower than the measurement voltage and calculating a voltage drop amount before and after the discharge. Further, in the discharge process in the low-temperature output characteristic inspection process S2, discharging with a constant current is performed. In the low temperature output characteristic inspection step S2, the reaction resistance of the secondary battery can be calculated based on the magnitude of the constant current used for the discharge and the amount of voltage drop before and after the discharge. However, in the secondary battery inspection method according to the first embodiment, since the magnitude of the constant current used for the discharge is determined in advance, the non-defective product determination described later is performed based only on the voltage drop amount.
次いで、実施の形態１にかかる二次電池の検査方法では、電圧降下量が閾値以下である場合に良品と判定する良品判定工程Ｓ３を行う。電圧降下量が閾値以下であるということは、二次電池の反応抵抗が十分に小さく低温出力能力に問題がないと考えられるためである。良品判定工程Ｓ３で検査対象の二次電池が不良品であると判断された場合、その時点で検査工程を終了する。一方、良品判定工程Ｓ３で検査対象の二次電池が良品であると判断された場合、容量確認工程Ｓ４を行う。 Next, in the secondary battery inspection method according to the first exemplary embodiment, a non-defective product determination step S3 is performed in which a non-defective product is determined when the voltage drop amount is equal to or less than a threshold value. The voltage drop amount being equal to or less than the threshold value is because the reaction resistance of the secondary battery is sufficiently small and it is considered that there is no problem in the low-temperature output capability. If it is determined in the non-defective product determination step S3 that the secondary battery to be inspected is a defective product, the inspection step is terminated at that time. On the other hand, when it is determined in the non-defective product determination step S3 that the secondary battery to be inspected is a non-defective product, the capacity confirmation step S4 is performed.
容量確認工程Ｓ４では、二次電池をエージングさせる電圧まで上昇させるまでの充電処理で消費された電流に基づき二次電池の電池容量を確認する。そして、容量確認工程Ｓ４で確認された電池容量が予め設定された規格値の範囲内であれば良品と判断する良品判定工程Ｓ５を行う。この良品判定工程Ｓ５において二次電池が不良品であると判断された場合、その時点で検査工程を終了する。一方、良品判定工程Ｓ５で検査対象の二次電池が良品であると判断された場合、エージング工程Ｓ６を行う。 In the capacity confirmation step S4, the battery capacity of the secondary battery is confirmed based on the current consumed in the charging process until the voltage is increased to a voltage for aging the secondary battery. Then, a non-defective product determination step S5 is performed in which the battery capacity confirmed in the capacity confirmation step S4 is determined to be non-defective if the battery capacity is within a preset standard value range. When it is determined that the secondary battery is defective in the non-defective product determination step S5, the inspection process is terminated at that time. On the other hand, when it is determined in the non-defective product determination step S5 that the secondary battery to be inspected is a non-defective product, an aging step S6 is performed.
エージング工程Ｓ６では、二次電池を所定の電圧でエージング処理する。また、エージング工程Ｓ６では、複数の二次電池の温度差が予め設定した温度範囲内となるように温度制御する。ここで、この温度範囲は、基準温度に対して−３℃〜＋３℃の範囲で設定されることが好ましい。 In the aging step S6, the secondary battery is aged at a predetermined voltage. In the aging step S6, the temperature is controlled so that the temperature difference between the plurality of secondary batteries is within a preset temperature range. Here, this temperature range is preferably set in a range of −3 ° C. to + 3 ° C. with respect to the reference temperature.
上述したように、実施の形態１にかかる二次電池の検査方法では、エージング工程Ｓ６を行う前に低温出力特性検査工程Ｓ２を行う。二次電池は、エージング工程Ｓ６を経ることで活性化されて使用可能となるが、活性化されることで反応抵抗が小さくなるという特徴がある。つまり、実施の形態１にかかる二次電池の検査方法では、エージング工程Ｓ６の前に容量確認工程Ｓ４を行うことで、大きな反応抵抗を測定できる。以下では、低温出力特性検査工程Ｓ２、充電工程Ｓ１の測定電圧、容量確認工程Ｓ４、エージング工程Ｓ６についてより詳細に説明する。 As described above, in the secondary battery inspection method according to the first embodiment, the low temperature output characteristic inspection step S2 is performed before the aging step S6. The secondary battery is activated through the aging step S6 and can be used. However, the activated secondary battery has a feature that the reaction resistance is reduced. That is, in the secondary battery inspection method according to the first embodiment, the large reaction resistance can be measured by performing the capacity confirmation step S4 before the aging step S6. Hereinafter, the low-temperature output characteristic inspection step S2, the measurement voltage of the charging step S1, the capacity confirmation step S4, and the aging step S6 will be described in more detail.
まず、低温出力特性検査工程Ｓ２について詳細に説明する。そこで、図２に実施の形態１にかかる二次電池のｃｏｌｅ−ｃｏｌｅプロットを示すグラフを示す。ｃｏｌｅ−ｃｏｌｅプロットは、複素インピーダンス平面プロットであり、測定対象がコンデンサ成分を含んでいると、プロットが半円を描き、その実軸（横軸）を切る点が二次電池の反応抵抗に相当する。図２に示す例でも、完全な半円ではないもののプロットは半円を描く。そして、その半円の始点と、半円が切れる点との間の抵抗値を以下では代用特性と称す。詳しくは後述するが、エージング工程Ｓ６の前に低温出力特性検査工程Ｓ２を行うことで、大きな値の代用特性を測定することができる。 First, the low temperature output characteristic inspection step S2 will be described in detail. FIG. 2 is a graph showing a colle-core plot of the secondary battery according to the first embodiment. The Cole-Cole plot is a complex impedance plane plot. When the measurement target includes a capacitor component, the plot draws a semicircle and the point that cuts the real axis (horizontal axis) corresponds to the reaction resistance of the secondary battery. . In the example shown in FIG. 2, the plot draws a semicircle although it is not a complete semicircle. The resistance value between the starting point of the semicircle and the point at which the semicircle is cut is hereinafter referred to as substitute characteristics. As will be described in detail later, by performing the low temperature output characteristic inspection step S2 before the aging step S6, it is possible to measure a substitute characteristic having a large value.
また、この代用特性は、二次電池の低温出力と相関関係を有する。そこで、図３に実施の形態１にかかる二次電池の検査方法における代用特性と低温出力との相関関係を説明するグラフを示す。図３に示すように、実施の形態１にかかる二次電池の検査方法では、相関係数Ｒ２が０．９１９と高い値を示す。 Further, this substitute characteristic has a correlation with the low temperature output of the secondary battery. FIG. 3 is a graph for explaining the correlation between the substitute characteristics and the low-temperature output in the secondary battery inspection method according to the first embodiment. As shown in FIG. 3, the inspection method of a secondary battery according to the first embodiment, showing a high value of the correlation coefficient R 2 is 0.919.
続いて、充電工程Ｓ１の測定電圧について説明する。二次電池は、測定電圧の大きさにより測定できる代用特性の大きさが大きく異なる。そこで、図４に実施の形態１にかかる二次電池の検査方法において二次電池に設定する測定電圧の違いによるｃｏｌｅ−ｃｏｌｅプロットの違いを示すグラフを示す。図４に示すように、ｃｏｌｅ−ｃｏｌｅプロットの半円は、測定電圧が低いほど大きくなる。 Then, the measurement voltage of charge process S1 is demonstrated. Secondary batteries vary greatly in the magnitude of substitute characteristics that can be measured depending on the magnitude of the measurement voltage. FIG. 4 is a graph showing the difference in the colle-coll plot due to the difference in the measurement voltage set for the secondary battery in the secondary battery inspection method according to the first embodiment. As shown in FIG. 4, the semicircle of the colle-coll plot becomes larger as the measurement voltage is lower.
ここで、当該測定電圧と、図３で説明した相関係数Ｒ２との関係について説明する。図５に実施の形態１にかかる二次電池の検査方法において二次電池に設定する測定電圧と、低温出力との相関係数と、の関係を説明するグラフを示す。図５では、測定時の電池電圧を横軸にとり、縦軸に各測定電圧において得られた代用特性と低温出力との相関係数を示した。図５に示すように、０．８以上の相関係数Ｒ２を得ようとした場合、測定電圧としては３．４４Ｖ以下の電圧としなけれならない。そこで、実施の形態１にかかる二次電池の検査方法では、測定電圧が３．４４Ｖ以下の電圧の領域であれば検査可能な測定電圧であるとする。 Here, the relationship between the measured voltage and the correlation coefficient R 2 described in FIG. 3 will be described. FIG. 5 shows a graph for explaining the relationship between the measurement voltage set in the secondary battery and the correlation coefficient between the low temperature output in the secondary battery inspection method according to the first embodiment. In FIG. 5, the horizontal axis represents the battery voltage at the time of measurement, and the vertical axis represents the correlation coefficient between the substitute characteristics and the low temperature output obtained at each measured voltage. As shown in FIG. 5, when obtaining a 0.8 or more correlation coefficients R 2, it does not have the following voltage 3.44V is used as a measuring voltage. Therefore, in the secondary battery inspection method according to the first embodiment, it is assumed that the measurement voltage can be inspected if the measurement voltage is in the region of 3.44 V or less.
測定電圧は、図５に示すように、二次電池に与える絶対的な電圧として設定することも可能であるが、二次電池の充電率（ＳＯＣ：State Of Charge）から設定することもできる。そこで、図６に実施の形態１にかかる二次電池の検査方法において二次電池に設定する充電率と、低温出力との相関係数と、の関係を説明するグラフを示す。図６に示すように、二次電池が出荷可能な状態であるときのＳＯＣが１５％未満となる電圧に二次電池の測定電圧を設定すると、相関係数Ｒ２として０．７以上の値を得ることができる。つまり、実施の形態１にかかる二次電池の検査方法では、測定電圧としてＳＯＣが１５％未満となる電圧に相当する電圧を設定可能とすることもできる。 As shown in FIG. 5, the measurement voltage can be set as an absolute voltage applied to the secondary battery, but can also be set from the state of charge (SOC) of the secondary battery. FIG. 6 shows a graph for explaining the relationship between the charging rate set for the secondary battery and the correlation coefficient between the low temperature output in the secondary battery inspection method according to the first embodiment. As shown in FIG. 6, when the measurement voltage of the secondary battery is set to a voltage at which the SOC is less than 15% when the secondary battery is ready for shipment, a value of 0.7 or more as the correlation coefficient R 2 Can be obtained. That is, in the secondary battery inspection method according to the first embodiment, a voltage corresponding to a voltage at which the SOC is less than 15% can be set as the measurement voltage.
続いて、容量確認工程Ｓ４について詳細に説明する。上述したように、容量確認工程Ｓ４では、二次電池をエージングさせる電圧まで上昇させるまでの充電処理で消費された電流に基づき二次電池の電池容量を確認する。そこで、エージング前の状態に行う容量確認工程Ｓ４により得られる充電容量（例えば、初充電容量）と、エージング後の区間容量との関係を説明するグラフを図７に示す。図７に示すように、エージング前に行う容量確認工程Ｓ４で得られる初充電容量（３．４４−３．９７Ｖ）と、エージング後に計測される区間容量（３．２９〜３．８１９Ｖ）と、の間には０．８８５５と高い相関係数Ｒ２を得ることができる。つまり、実施の形態１にかかる二次電池の検査方法では、容量確認工程Ｓ４において得た初充電容量から図７のグラフを用いて計算を行うことで、高い精度でエージング後の電池容量を推定することができる。 Subsequently, the capacity confirmation step S4 will be described in detail. As described above, in the capacity confirmation step S4, the battery capacity of the secondary battery is confirmed based on the current consumed in the charging process until the voltage is increased to the voltage for aging the secondary battery. Therefore, FIG. 7 shows a graph for explaining the relationship between the charge capacity (for example, initial charge capacity) obtained by the capacity confirmation step S4 performed before the aging and the section capacity after the aging. As shown in FIG. 7, the initial charge capacity (3.44-3.97V) obtained in the capacity confirmation step S4 performed before aging, the section capacity (3.29 to 3.819V) measured after aging, A correlation coefficient R 2 as high as 0.8855 can be obtained. That is, in the secondary battery inspection method according to the first embodiment, the battery capacity after aging is estimated with high accuracy by performing calculation using the graph of FIG. 7 from the initial charge capacity obtained in the capacity confirmation step S4. can do.
続いて、エージング工程Ｓ６について説明する。実施の形態１にかかる二次電池の検査方法では、エージング工程Ｓ６の前に代用特性を測定するため、エージング温度によりこの代用特性がばらつくことが懸念される。そこで、図８に実施の形態１にかかる二次電池の検査方法におけるエージング温度と代用特性のばらつきとの関係を説明するグラフを示す。図８では、エージング温度により変動する代用特性の範囲をハッチングの領域で示した。この図８からわかるように、代用抵抗は、エージング温度により変動する。そこで、実施の形態１にかかる二次電池の検査方法では、エージング温度として、代用特性のばらつきが−５ｍΩ〜＋５ｍΩの範囲に収まる範囲をエージング温度の管理範囲とする。より具体的には、実施の形態１にかかる二次電池の検査方法では、６３℃を基準温度とし、この基準温度に対して−３℃〜＋３℃の範囲をエージング温度の管理範囲とする。 Subsequently, the aging step S6 will be described. In the secondary battery inspection method according to the first embodiment, since the substitute characteristics are measured before the aging step S6, there is a concern that the substitute characteristics vary depending on the aging temperature. FIG. 8 is a graph for explaining the relationship between the aging temperature and the variation in the substitute characteristics in the secondary battery inspection method according to the first embodiment. In FIG. 8, the range of the substitute characteristics that fluctuates depending on the aging temperature is indicated by a hatched area. As can be seen from FIG. 8, the substitute resistance varies depending on the aging temperature. Therefore, in the secondary battery inspection method according to the first embodiment, the aging temperature management range is a range in which the variation in the substitute characteristics falls within the range of −5 mΩ to +5 mΩ as the aging temperature. More specifically, in the secondary battery inspection method according to the first embodiment, 63 ° C. is set as a reference temperature, and a range of −3 ° C. to + 3 ° C. is set as a management range of the aging temperature with respect to the reference temperature.
ここで、エージング後に容量確認検査及び低温出力検査を行う比較例と対比して、実施の形態１にかかる二次電池の検査方法について説明する。そこで、比較例にかかる二次電池の検査方法のフローチャートを図９に示す。 Here, the secondary battery inspection method according to the first embodiment will be described in comparison with a comparative example in which a capacity check inspection and a low-temperature output inspection are performed after aging. FIG. 9 shows a flowchart of the secondary battery inspection method according to the comparative example.
図９に示すように、比較例にかかる二次電池の検査方法では、まず、初充電工程Ｓ１１を行う。この初充電工程では、二次電池の電圧がエージング処理の電圧に達するまで充電を行う。次いで、高温エージング工程Ｓ１２を行う。この高温エージング工程Ｓ１２は、図１で説明したエージング工程Ｓ６と同じ工程である。次いで、自己放電工程Ｓ１３を行う。この自己放電工程Ｓ１３では、二次電池を放置した状態で二次電池に放電を行わせる。 As shown in FIG. 9, in the secondary battery inspection method according to the comparative example, first, an initial charging step S11 is performed. In this initial charging step, charging is performed until the voltage of the secondary battery reaches the voltage of the aging process. Next, the high temperature aging step S12 is performed. This high temperature aging process S12 is the same process as the aging process S6 described in FIG. Next, the self-discharge process S13 is performed. In this self-discharge step S13, the secondary battery is discharged while the secondary battery is left unattended.
その後、比較例にかかる二次電池の検査方法では、容量確認工程Ｓ１４を行う。この容量確認工程Ｓ１４では、二次電池に対して定電流で放電を行わせ、放電時に得られる電流値から二次電池の容量確認を行う。次いで、容量確認工程Ｓ１４で得られた電池容量が規格の範囲内であるか否かを確認する良品判定工程Ｓ１５を行う。この良品判定工程Ｓ１５において二次電池が不良品であると判断された場合、検査工程を終了する。一方、良品判定工程Ｓ１５において二次電池が良品であると判断された場合、比較例にかかる二次電池の検査方法では、二次電池の電圧を測定電圧まで上昇させた上でエージング工程Ｓ１６を行う。その後、比較例にかかる二次電池の検査方法では、低温出力特性検査工程Ｓ１７を行う。この低温出力特性検査工程Ｓ１７は、図１で示した低温出力特性検査工程Ｓ２と同じ処理である。そして、低温出力特性検査工程Ｓ１７において得られた電圧降下量が閾値以下であるか否かを判断する良品判定工程Ｓ１８を行う。良品判定工程Ｓ１８で検査対象の二次電池が不良品であると判断された場合、当該二次電池を不良品と判定した上で検査工程を終了する。一方、良品判定工程Ｓ１８で検査対象の二次電池が良品であると判断された場合、当該二次電池を出荷可能な状態であると判断して検査工程を終了する。 Thereafter, in the secondary battery inspection method according to the comparative example, a capacity confirmation step S14 is performed. In this capacity confirmation step S14, the secondary battery is discharged at a constant current, and the capacity of the secondary battery is confirmed from the current value obtained at the time of discharge. Next, a non-defective product determination step S15 for confirming whether or not the battery capacity obtained in the capacity confirmation step S14 is within the standard range is performed. When it is determined that the secondary battery is a defective product in the non-defective product determination step S15, the inspection process is terminated. On the other hand, when it is determined in the non-defective product determination step S15 that the secondary battery is a non-defective product, in the secondary battery inspection method according to the comparative example, the aging step S16 is performed after increasing the voltage of the secondary battery to the measurement voltage. Do. Thereafter, in the secondary battery inspection method according to the comparative example, a low-temperature output characteristic inspection step S17 is performed. This low temperature output characteristic inspection step S17 is the same process as the low temperature output characteristic inspection step S2 shown in FIG. Then, a non-defective product determination step S18 is performed to determine whether or not the voltage drop amount obtained in the low temperature output characteristic inspection step S17 is equal to or less than a threshold value. When it is determined in the non-defective product determination step S18 that the secondary battery to be inspected is defective, the secondary battery is determined to be defective and the inspection process is terminated. On the other hand, when it is determined in the non-defective product determination step S18 that the secondary battery to be inspected is a non-defective product, it is determined that the secondary battery can be shipped and the inspection process is terminated.
続いて、比較例にかかる二次電池の検査方法の低温出力特性検査工程Ｓ１７で得られる代用特性と、実施の形態１にかかる二次電池の検査方法の低温出力特性検査工程Ｓ２で得られる代用特性と、の違いについて説明する。そこで、図１０に実施の形態１にかかる二次電池の検査方法における二次電池のｃｏｌｅ−ｃｏｌｅプロットと、比較例にかかる二次電池の検査方法における二次電池のｃｏｌｅ−ｃｏｌｅプロットとと、を比較する図を示す。 Subsequently, the substitute characteristics obtained in the low temperature output characteristic inspection step S17 of the secondary battery inspection method according to the comparative example, and the substitute characteristics obtained in the low temperature output characteristic inspection step S2 of the secondary battery inspection method according to the first embodiment. The difference between characteristics will be described. Therefore, in FIG. 10, the secondary battery call-core plot in the secondary battery inspection method according to the first embodiment, and the secondary battery colle-core plot in the secondary battery inspection method according to the comparative example, The figure which compares is shown.
図１０に示すように、比較例にかかる二次電池の検査方法において得られる代用特性は、実施の形態１にかかる二次電池の検査方法において得られる代用特性よりも著しく小さい。つまり、エージング処理後に代用特性を得た場合、エージング処理前に得た代用特性よりも小さな代用特性しか得られない。 As shown in FIG. 10, the substitute characteristic obtained in the secondary battery inspection method according to the comparative example is significantly smaller than the substitute characteristic obtained in the secondary battery inspection method according to the first embodiment. That is, when the substitute characteristic is obtained after the aging process, only a substitute characteristic smaller than the substitute characteristic obtained before the aging process can be obtained.
また、図１１に比較例にかかる二次電池の検査方法における代用特性と低温出力との相関関係を説明するグラフを示す。図１１に示すように、比較例にかかる二次電池の検査方法における代用特性と低温出力との相関係数Ｒ２は、０．４９７５であり、図３で説明した実施の形態１にかかる二次電池の検査方法において得られる相関係数Ｒ２より遙かに小さい。このようなことから、実施の形態１にかかる二次電池の検査方法は、測定精度が高いことがわかる。 FIG. 11 is a graph illustrating the correlation between the substitute characteristics and the low-temperature output in the secondary battery inspection method according to the comparative example. As shown in FIG. 11, the correlation coefficient R 2 between the substitute characteristic and the low-temperature output in the secondary battery inspection method according to the comparative example is 0.4975, and the second embodiment according to the first embodiment described with reference to FIG. much smaller than the correlation coefficient R 2 obtained in the inspection method of the next cell. From this, it can be seen that the secondary battery inspection method according to the first embodiment has high measurement accuracy.
続いて、図１２に実施の形態１にかかる二次電池の検査方法の検査時間を説明する検査工程中の二次電池の電圧変化を示すグラフを示す。図１２には、比較例にかかる二次電池の検査方法を適用した検査工程中の二次電池の電圧変化も示した。 Next, FIG. 12 shows a graph showing the voltage change of the secondary battery during the inspection process for explaining the inspection time of the secondary battery inspection method according to the first embodiment. FIG. 12 also shows the voltage change of the secondary battery during the inspection process to which the secondary battery inspection method according to the comparative example is applied.
図１２に示すように、比較例にかかる二次電池の検査方法では、容量確認検査を省略したとしても検査時間はほとんど縮まらない。これは、高温エージング工程Ｓ１２及びエージング工程Ｓ１６に長い時間を要してしまうためである。一方、実施の形態１にかかる二次電池の検査方法では、低温出力特性検査工程Ｓ２及び容量確認工程Ｓ４を行い、さらにその後にエージング工程Ｓ６を行ったとしても、比較例にかかる二次電池の検査方法よりも短い時間で検査を完了することができる。さらに、実施の形態１にかかる二次電池の検査方法では、エージング工程Ｓ６を省略することで、大幅に検査時間を短縮することができる。 As shown in FIG. 12, in the secondary battery inspection method according to the comparative example, the inspection time is hardly shortened even if the capacity check inspection is omitted. This is because the high temperature aging process S12 and the aging process S16 require a long time. On the other hand, in the secondary battery inspection method according to the first embodiment, even if the low temperature output characteristic inspection step S2 and the capacity confirmation step S4 are performed, and then the aging step S6 is performed, the secondary battery according to the comparative example is The inspection can be completed in a shorter time than the inspection method. Furthermore, in the secondary battery inspection method according to the first embodiment, the inspection time can be significantly shortened by omitting the aging step S6.
上記説明より、実施の形態１にかかる二次電池の検査方法によれば、二次電池の代用特性を高い精度で測定することができる。これにより、実施の形態１にかかる二次電池の検査方法では、高い精度で低温出力特性を検査することが可能になる。 From the above description, according to the inspection method of the secondary battery according to the first embodiment, the substitute characteristics of the secondary battery can be measured with high accuracy. As a result, the secondary battery inspection method according to the first embodiment can inspect the low-temperature output characteristics with high accuracy.
また、実施の形態１にかかる二次電池の検査方法では、エージング工程Ｓ６において、複数の二次電池間の温度差を所定の温度範囲内で管理することで、エージング後の代用特性のばらつきを抑制し、かつ、低温出力特性のばらつきを抑制することができる。この温度管理は、設備の追加を行うことなく実施可能である。 Further, in the secondary battery inspection method according to the first embodiment, in the aging step S6, the temperature difference between the plurality of secondary batteries is managed within a predetermined temperature range, so that the variation in the substitute characteristics after aging is changed. It is possible to suppress the variation in low-temperature output characteristics. This temperature control can be carried out without adding equipment.
また、実施の形態１にかかる二次電池の検査方法では、エージング等にかかる時間を削減して、検査時間を大幅に短縮することができる。また、実施の形態１にかかる二次電池の検査方法では、容量確認工程Ｓ４において放電を必要としないため、容量確認工程で用いる放電装置を削減することができる。 Further, in the secondary battery inspection method according to the first embodiment, the time required for aging and the like can be reduced, and the inspection time can be greatly shortened. In the secondary battery inspection method according to the first embodiment, since no discharge is required in the capacity confirmation step S4, the number of discharge devices used in the capacity confirmation step can be reduced.
上記説明は、本発明者によってなされた発明を実施の形態に基づき具体的に説明したが、本発明は既に述べた実施の形態に限定されるものではなく、その要旨を逸脱しない範囲において種々の変更が可能であることはいうまでもない。 In the above description, the invention made by the present inventor has been specifically described based on the embodiments. However, the present invention is not limited to the embodiments already described, and various modifications can be made without departing from the scope of the invention. It goes without saying that changes are possible.
Ｓ１ 充電工程
Ｓ２ 低温出力特性検査工程
Ｓ３、Ｓ５ 良品判定工程
Ｓ４ 容量確認工程
Ｓ６ エージング工程
S1 Charging process S2 Low temperature output characteristic inspection process S3, S5 Non-defective product determination process S4 Capacity confirmation process S6 Aging process
Claims (5)
未エージング状態の検査対象セルを予め定められた所定の電圧まで充電する充電工程と、
未エージング状態において前記所定の電圧以下の電圧で放電を行い、前記放電の前後の電圧降下量を算出して前記電圧降下量と低温出力特性の相関関係とに基づき低温出力検査を行う電圧降下量算出工程と、
前記電圧降下量が閾値以下である場合に良品と判定する良品判定工程と、
前記良品判定工程後にエージングを行うエージング工程と、
を有する二次電池の検査方法。 A method for inspecting a secondary battery,
A charging step of charging the non-aging test target cell to a predetermined voltage;
A voltage drop amount for performing discharge at a voltage equal to or lower than the predetermined voltage in an unaged state, calculating a voltage drop amount before and after the discharge, and performing a low temperature output inspection based on a correlation between the voltage drop amount and a low temperature output characteristic A calculation process;
A non-defective product determination step for determining a non-defective product when the voltage drop amount is equal to or less than a threshold value;
An aging step of aging after the non-defective product determination step;
A method for inspecting a secondary battery.
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| CN201610105618.3A CN105929333B (en) | 2015-02-27 | 2016-02-25 | The inspection method of secondary cell |
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