JP5972209B2

JP5972209B2 - Negative electrode discharge capacity recovery method and negative electrode discharge capacity recovery device

Info

Publication number: JP5972209B2
Application number: JP2013084193A
Authority: JP
Inventors: 大輔木庭; 幸大武田; 公一市川; 高橋　泰博; 泰博高橋; 三井　正彦; 正彦三井
Original assignee: Toyota Motor Corp; Primearth EV Energy Co Ltd
Current assignee: Toyota Motor Corp; Primearth EV Energy Co Ltd
Priority date: 2013-04-12
Filing date: 2013-04-12
Publication date: 2016-08-17
Anticipated expiration: 2033-04-12
Also published as: JP2014207789A

Description

本発明は、正極と負極と復帰型の安全弁装置とを備えるニッケル水素蓄電池について、負極の放電容量を増加させる負極放電容量回復方法、及び、負極放電容量回復装置に関する。 The present invention relates to a negative electrode discharge capacity recovery method for increasing the discharge capacity of a negative electrode and a negative electrode discharge capacity recovery device for a nickel metal hydride storage battery including a positive electrode, a negative electrode, and a resettable safety valve device.

ニッケル水素蓄電池は、一般に、負極の容量を正極の容量よりも大きくしているので、電池の放電容量は、正極の容量によって制限される（以下、これを正極規制とも言う）。このように正極規制とすることにより、過充電時及び過放電時における電池内圧の上昇を抑制できる。なお、負極を正極と対比して、充電可能な過剰な未充電部分を充電リザーブと呼び、放電可能な過剰な充電部分を放電リザーブと呼ぶ。 Since nickel-metal hydride storage batteries generally have a negative electrode capacity larger than the positive electrode capacity, the discharge capacity of the battery is limited by the positive electrode capacity (hereinafter also referred to as positive electrode regulation). By setting the positive electrode in this way, it is possible to suppress an increase in battery internal pressure during overcharge and overdischarge. In addition, the negative electrode is compared with the positive electrode, an excessively uncharged portion that can be charged is referred to as a charge reserve, and an excessively charged portion that can be discharged is referred to as a discharge reserve.

ところで、近年の調査により、ニッケル水素蓄電池の中には、微量の水素ガスが電池ケースを透過して電池外部に漏れ続けるものがあることが判っている。このように水素ガスが電池外部に漏出すると、電池ケース内の水素分圧の平衡を保つべく、水素漏出量に応じて負極の水素吸蔵合金から水素が排出される。これにより、負極の放電リザーブ容量が減少する。この水素の漏出は、非常にゆっくりと進行するため、比較的短い使用期間では問題とならない。 By the way, according to recent research, it has been found that some nickel-metal hydride storage batteries continue to leak a small amount of hydrogen gas through the battery case and to the outside of the battery. When hydrogen gas leaks out of the battery in this manner, hydrogen is discharged from the hydrogen storage alloy of the negative electrode in accordance with the amount of hydrogen leakage in order to maintain the equilibrium of the hydrogen partial pressure in the battery case. This reduces the discharge reserve capacity of the negative electrode. This hydrogen leakage proceeds very slowly and is not a problem for relatively short periods of use.

しかしながら、使用期間が長期にわたると、正極と負極の容量のバランスが悪くなると共に負極の容量が減少し、負極の放電リザーブ容量が消滅してしまうことがある。その結果、ニッケル水素蓄電池が負極規制（電池の放電容量が負極の容量によって制限されることを言う）となり、電池の放電容量が減少して電池特性が大きく低下してしまうことがあった。ニッケル水素蓄電池を、電気自動車やハイブリッド自動車などの電源として用いる場合には、長期間の寿命が要求されるため、このような電池特性の低下は問題となる。 However, over a long period of use, the capacity balance between the positive electrode and the negative electrode may deteriorate, the capacity of the negative electrode may decrease, and the discharge reserve capacity of the negative electrode may disappear. As a result, the nickel-metal hydride storage battery is subject to negative electrode regulation (which means that the discharge capacity of the battery is limited by the capacity of the negative electrode), and the battery discharge capacity is reduced, and the battery characteristics may be greatly deteriorated. When a nickel metal hydride storage battery is used as a power source for an electric vehicle, a hybrid vehicle, or the like, a long life is required, and such a deterioration in battery characteristics becomes a problem.

この課題を解決すべく、負極の放電容量の減少により電池容量が低下したニッケル水素蓄電池について、負極の放電容量を増加（回復）させて、電池を再生する方法が提案されている（例えば特許文献１参照）。ニッケル水素蓄電池を過充電すると、正極から電子が放出されると共に、電解液の分解により酸素ガスが発生する。一方、負極では、水の分解により発生した水素が水素吸蔵合金に吸蔵される。但し、正極から発生した酸素ガスは、通常、水素吸蔵合金に吸蔵された水素との反応により消費される（水が生成される）ため、結局、過充電するだけでは、負極の水素吸蔵合金に吸蔵される水素を増加させることはできない。 In order to solve this problem, a method for regenerating a battery by increasing (recovering) the discharge capacity of the negative electrode has been proposed for a nickel metal hydride storage battery whose battery capacity has been reduced by decreasing the discharge capacity of the negative electrode (for example, Patent Documents). 1). When the nickel metal hydride storage battery is overcharged, electrons are released from the positive electrode and oxygen gas is generated due to decomposition of the electrolyte. On the other hand, in the negative electrode, hydrogen generated by the decomposition of water is stored in the hydrogen storage alloy. However, the oxygen gas generated from the positive electrode is normally consumed by the reaction with the hydrogen stored in the hydrogen storage alloy (water is generated). The stored hydrogen cannot be increased.

これに対し、特許文献１では、ニッケル水素蓄電池を過充電して正極から発生させた酸素ガスの少なくとも一部を電池外部に排出する。これにより、電池内部では、過充電に伴って負極の水素吸蔵合金に吸蔵された水素が、酸素ガスに対し過剰となる。その結果、過充電により負極の水素吸蔵合金に吸蔵された水素の少なくとも一部を、発生した酸素ガスと反応させることなく水素吸蔵合金に吸蔵されたまま残存させる（負極の放電容量を増加させる）ことができる。かくして、負極の放電容量を回復させることができる。 On the other hand, in Patent Document 1, at least a part of oxygen gas generated from the positive electrode by overcharging the nickel-metal hydride storage battery is discharged to the outside of the battery. Thereby, in the battery, hydrogen stored in the hydrogen storage alloy of the negative electrode due to overcharge becomes excessive with respect to the oxygen gas. As a result, at least a portion of the hydrogen occluded in the hydrogen storage alloy of the negative electrode due to overcharging is left to be stored in the hydrogen storage alloy without reacting with the generated oxygen gas (increasing the discharge capacity of the negative electrode). be able to. Thus, the discharge capacity of the negative electrode can be recovered.

特開２００８−２３５０３６号公報JP 2008-235036 A

しかしながら、特許文献１の方法では、ニッケル水素蓄電池の過充電をどの程度行えば、負極の放電容量がどの程度増加するのかは不明である。このため、負極の放電容量を所望の容量増加させたい場合に、ニッケル水素蓄電池の過充電をどれだけ行えば良いのか判らない。ニッケル水素蓄電池は、過充電しすぎると電池の劣化を生じる。また、充電時間が長いと生産性が悪くなる。従って、必要以上に過充電を行うのは好ましくない。
そこで、本発明者が実験を重ねて調査した結果、充電(過充電に限られない)による負極の放電容量の容量増加量は、回復前後でのニッケル水素蓄電池の質量減少量との間に、高い相関があることが判明した。 However, in the method of Patent Document 1, it is unclear how much the nickel-hydrogen storage battery is overcharged and how much the discharge capacity of the negative electrode increases. For this reason, when it is desired to increase the discharge capacity of the negative electrode to a desired capacity, it is not known how much overcharge of the nickel-metal hydride storage battery should be performed. A nickel metal hydride storage battery will deteriorate if it is overcharged too much. Further, if the charging time is long, the productivity is deteriorated. Therefore, it is not preferable to overcharge more than necessary.
Therefore, as a result of repeated investigations by the present inventors, the capacity increase amount of the discharge capacity of the negative electrode due to charging (not limited to overcharging) is between the mass decrease amount of the nickel metal hydride storage battery before and after recovery, A high correlation was found.

本発明は、かかる現状に鑑みてなされたものであって、ニッケル水素蓄電池について負極の放電容量を所望の容量増加させることができる負極放電容量回復方法、及び、負極放電容量回復装置を提供することを目的とする。 The present invention has been made in view of the present situation, and provides a negative electrode discharge capacity recovery method and a negative electrode discharge capacity recovery device capable of increasing the discharge capacity of a negative electrode for a nickel metal hydride storage battery by a desired capacity. With the goal.

上記課題を解決するための本発明の一態様は、正極と負極と復帰型の安全弁装置とを備えるニッケル水素蓄電池について、前記負極の放電容量を増加させる負極放電容量回復方法であって、前記負極の前記放電容量について目標容量増加量を設定する増加量設定ステップと、回復前後の前記ニッケル水素蓄電池の質量減少量と前記負極の前記放電容量の容量増加量との相関に基づいて、設定された前記目標容量増加量に対応する目標質量減少量を設定する質量減少量設定ステップと、前記ニッケル水素蓄電池を充電して前記正極から酸素ガスを発生させ、当該酸素ガスの少なくとも一部を、開弁した前記安全弁装置を通じて電池外部に排出して、前記負極の前記放電容量を増加させる放電容量増加ステップと、を備え、前記放電容量増加ステップは、前記質量減少量が前記目標質量減少量に達するまで、前記ニッケル水素蓄電池の充電を行う負極放電容量回復方法である。 One aspect of the present invention for solving the above problems is a negative electrode discharge capacity recovery method for increasing the discharge capacity of the negative electrode for a nickel-metal hydride storage battery including a positive electrode, a negative electrode, and a resettable safety valve device, the negative electrode An increase amount setting step for setting a target capacity increase amount for the discharge capacity of the battery, and a correlation between a mass decrease amount of the nickel-metal hydride storage battery before and after recovery and a capacity increase amount of the discharge capacity of the negative electrode. A mass reduction amount setting step for setting a target mass reduction amount corresponding to the target capacity increase amount; charging the nickel-metal hydride storage battery to generate oxygen gas; and opening at least a part of the oxygen gas A discharge capacity increasing step for discharging to the outside of the battery through the safety valve device and increasing the discharge capacity of the negative electrode, and the discharge capacity increasing step. Flop, until said mass reduction amount reaches the target weight loss is a negative electrode discharge capacity recovery method for charging of the nickel-metal hydride storage battery.

負極の放電容量を増加（回復）させるにあたり、回復前後でのニッケル水素蓄電池の質量減少量と負極の放電容量の容量増加量との相関を、予め把握しておく。そして、この負極放電容量回復方法では、まず負極の放電容量について目標容量増加量を設定する（容量増加量設定ステップ）。更に、電池の質量減少量と負極の容量増加量との相関に基づいて、設定された目標容量増加量に対応する目標質量減少量を設定する（質量減少量設定ステップ）。その後、ニッケル水素蓄電池を充電して、負極の放電容量を増加させる（放電容量増加ステップ）。具体的には、電池の質量減少量が目標質量減少量に達するまで、ニッケル水素蓄電池の充電を行う。これにより、目標質量減少量に対応する目標容量増加量の分だけ、負極の放電容量を増加させることができる。このように上述の負極放電容量回復方法によれば、負極の放電容量を所望の容量増加させることができる。 In increasing (recovering) the discharge capacity of the negative electrode, a correlation between the amount of decrease in the mass of the nickel-metal hydride storage battery and the increase in capacity of the discharge capacity of the negative electrode before and after recovery is grasped in advance. In this negative electrode discharge capacity recovery method, first, a target capacity increase amount is set for the negative electrode discharge capacity (capacity increase amount setting step). Further, a target mass decrease amount corresponding to the set target capacity increase amount is set based on the correlation between the battery mass decrease amount and the negative electrode capacity increase amount (mass decrease amount setting step). Thereafter, the nickel metal hydride storage battery is charged to increase the discharge capacity of the negative electrode (discharge capacity increase step). Specifically, the nickel metal hydride storage battery is charged until the mass reduction amount of the battery reaches the target mass reduction amount. Thereby, the discharge capacity of the negative electrode can be increased by the amount of the target capacity increase corresponding to the target mass reduction amount. Thus, according to the negative electrode discharge capacity recovery method described above, the discharge capacity of the negative electrode can be increased by a desired capacity.

なお、負極の放電容量を増加させるための「充電」は、ＳＯＣ０％〜ＳＯＣ１００％の間で行う通常の充電のほか、ＳＯＣ１００％を越えた状態で行う充電、即ち、いわゆる過充電も含む。
また、「放電容量増加ステップ」は、後述するように、ニッケル水素蓄電池の質量を継続的に測定し、質量減少量を継続的に算出しながら行ってもよいし、ニッケル水素蓄電池の質量を例えば所定時間毎に断続的に測定し、質量減少量を所定時間毎に断続的に算出しながら行ってもよい。
また、「放電容量増加ステップ」において、発生させた酸素ガスを安全弁装置を通じて電池外部に排出する方法としては、充電（過充電）により上昇した電池内圧が開弁圧に達することで、安全弁装置を自動的に開弁させて、酸素ガスの少なくとも一部を排出させる方法が挙げられる。また、電池内圧が開弁圧に達する前に安全弁装置を強制的に開弁させて、酸素ガスの少なくとも一部を排出させてもよい。 “Charging” for increasing the discharge capacity of the negative electrode includes normal charging performed between SOC 0% and SOC 100%, as well as charging performed in a state exceeding SOC 100%, that is, so-called overcharging.
Further, as described later, the “discharge capacity increasing step” may be performed while continuously measuring the mass of the nickel-metal hydride storage battery and calculating the mass decrease amount. The measurement may be performed intermittently every predetermined time, and the mass reduction amount may be calculated intermittently every predetermined time.
Also, in the “discharge capacity increasing step”, the generated oxygen gas can be discharged to the outside of the battery through the safety valve device. When the battery internal pressure increased by charging (overcharge) reaches the valve opening pressure, the safety valve device is A method of automatically opening the valve to discharge at least a part of the oxygen gas can be mentioned. Further, the safety valve device may be forcibly opened before the battery internal pressure reaches the valve opening pressure to discharge at least a part of the oxygen gas.

更に、上記の負極放電容量回復方法であって、前記放電容量増加ステップは、前記ニッケル水素蓄電池の質量を継続的に測定し、前記質量減少量を継続的に算出しながら行う負極放電容量回復方法とすると良い。 Furthermore, in the above negative electrode discharge capacity recovery method, the discharge capacity increase step is performed by continuously measuring the mass of the nickel-metal hydride storage battery and continuously calculating the mass decrease amount. And good.

この負極放電容量回復方法では、ニッケル水素蓄電池の質量を継続的に測定し質量減少量を継続的に算出しながら、放電容量増加ステップを行う。これにより、ニッケル水素蓄電池の実際の質量減少量が目標質量減少量に到達したのと同時に、放電容量増加ステップを終了することができる。従って、負極の放電容量を、より正確に目標容量増加量だけ増加させることができる。 In this negative electrode discharge capacity recovery method, the discharge capacity increase step is performed while continuously measuring the mass of the nickel metal hydride storage battery and calculating the mass decrease amount continuously. Thereby, the discharge capacity increase step can be completed at the same time when the actual mass decrease amount of the nickel metal hydride storage battery reaches the target mass decrease amount. Therefore, the discharge capacity of the negative electrode can be more accurately increased by the target capacity increase amount.

更に、上記のいずれかに記載の負極放電容量回復方法であって、前記放電容量増加ステップは、前記安全弁装置の開弁を強制的に行って、発生させた前記酸素ガスの少なくとも一部を排出する負極放電容量回復方法とすると良い。 Furthermore, in the negative electrode discharge capacity recovery method according to any one of the above, the discharge capacity increasing step forcibly opens the safety valve device to discharge at least a part of the generated oxygen gas. A negative electrode discharge capacity recovery method is preferable.

この負極放電容量回復方法では、安全弁装置の開弁を強制的に行って、充電により発生させた酸素ガスの少なくとも一部を電池外部に排出する。これにより、発生した酸素ガスが水素吸蔵合金に吸蔵された水素と反応して消費される（水が生成される）のを抑制できる。従って、負極の放電容量の容量回復効率を向上させることができる。 In this negative electrode discharge capacity recovery method, the safety valve device is forcibly opened to discharge at least a part of the oxygen gas generated by charging to the outside of the battery. Thereby, it can suppress that the generated oxygen gas reacts with the hydrogen occluded by the hydrogen occlusion alloy and is consumed (water is generated). Therefore, the capacity recovery efficiency of the discharge capacity of the negative electrode can be improved.

更に、上記のいずれかに記載の負極放電容量回復方法であって、前記放電容量増加ステップは、充電開始時の前記ニッケル水素蓄電池の温度を３０℃以下にして行う負極放電容量回復方法とすると良い。 Furthermore, in the negative electrode discharge capacity recovery method according to any one of the above, the discharge capacity increase step may be a negative electrode discharge capacity recovery method performed by setting the temperature of the nickel-metal hydride storage battery at 30 ° C. or less at the start of charging. .

このように充電開始時の前記ニッケル水素蓄電池の温度を３０℃以下とすることで、負極の放電容量の容量回復効率を向上させることができる。 Thus, the capacity | capacitance recovery efficiency of the discharge capacity of a negative electrode can be improved by making the temperature of the said nickel hydride storage battery at the time of a charge start into 30 degrees C or less.

更に、上記のいずれかに記載の負極放電容量回復方法であって、前記放電容量増加ステップは、充電電流値を６．０Ｃ以下にして行う負極放電容量回復方法とすると良い。 Furthermore, in any of the above-described negative electrode discharge capacity recovery methods, the discharge capacity increase step may be a negative electrode discharge capacity recovery method that is performed with a charging current value of 6.0 C or less.

このように充電電流値を６．０Ｃ以下とすることで、負極の放電容量の容量回復効率を向上させることができる。 Thus, the capacity | capacitance recovery efficiency of the discharge capacity of a negative electrode can be improved because a charging current value shall be 6.0 C or less.

また、他の態様は、正極と負極と復帰型の安全弁装置とを備えるニッケル水素蓄電池について、前記負極の放電容量を増加させる負極放電容量回復装置であって、前記ニッケル水素蓄電池を充電する充電回路と、前記充電回路による前記ニッケル水素蓄電池の充電を制御する充電制御装置と、前記ニッケル水素蓄電池の質量を測定する質量測定装置と、を備え、前記充電制御装置は、前記負極の前記放電容量について目標容量増加量を設定する増加量設定手段と、回復前後の前記ニッケル水素蓄電池の質量減少量と前記負極の前記放電容量の容量増加量との相関に基づいて、設定された前記目標容量増加量に対応する目標質量減少量を設定する質量減少量設定手段と、前記充電回路で前記ニッケル水素蓄電池を充電して前記正極から酸素ガスを発生させ、当該酸素ガスの少なくとも一部を、開弁した前記安全弁装置を通じて電池外部に排出して、前記負極の前記放電容量を増加させる放電容量増加手段であって、前記質量測定装置による測定で得られる前記質量減少量が前記目標質量減少量に達するまで、前記ニッケル水素蓄電池の充電を行う放電容量増加手段と、を有する負極放電容量回復装置である。 Another aspect is a negative electrode discharge capacity recovery device for increasing a discharge capacity of the negative electrode for a nickel metal hydride storage battery including a positive electrode, a negative electrode, and a resettable safety valve device, and a charging circuit for charging the nickel hydride storage battery And a charge control device that controls charging of the nickel-metal hydride storage battery by the charging circuit, and a mass measurement device that measures the mass of the nickel-metal hydride storage battery, wherein the charge control device is configured for the discharge capacity of the negative electrode. Based on a correlation between an increase amount setting means for setting a target capacity increase amount, and a mass decrease amount of the nickel-metal hydride storage battery before and after recovery and a capacity increase amount of the discharge capacity of the negative electrode, the set target capacity increase amount A mass reduction amount setting means for setting a target mass reduction amount corresponding to the above, and charging the nickel-metal hydride storage battery with the charging circuit to supply oxygen gas from the positive electrode A discharge capacity increasing means for increasing the discharge capacity of the negative electrode by discharging at least a part of the oxygen gas to the outside of the battery through the opened safety valve device and measuring the mass measurement device. And a discharge capacity increasing means for charging the nickel-metal hydride storage battery until the obtained mass decrease amount reaches the target mass decrease amount.

この負極放電容量回復装置では、充電制御装置のうち、増加量設定手段において、負極の放電容量について目標容量増加量を設定する。更に、質量減少量設定手段において、電池の質量減少量と負極の容量増加量との相関に基づいて、設定された目標容量増加量に対応する目標質量減少量を設定する。その後、放電容量増加手段により、充電回路でニッケル水素蓄電池を充電して、負極の放電容量を増加させる。具体的には、質量測定装置による測定から算出される質量減少量が目標質量減少量に達するまで、ニッケル水素蓄電池の充電を行う。これにより、目標質量減少量に対応する目標容量増加量の分だけ、負極の放電容量を増加させることができる。このように上述の負極放電容量回復装置によれば、負極の放電容量を所望の容量増加させることができる。 In this negative electrode discharge capacity recovery device, an increase amount setting means in the charge control device sets a target capacity increase amount for the negative electrode discharge capacity. Further, the mass decrease amount setting means sets a target mass decrease amount corresponding to the set target capacity increase amount based on the correlation between the battery mass decrease amount and the negative electrode capacity increase amount. Thereafter, the nickel hydride storage battery is charged by the charging circuit by the discharge capacity increasing means to increase the discharge capacity of the negative electrode. Specifically, the nickel metal hydride storage battery is charged until the mass reduction amount calculated from the measurement by the mass measuring device reaches the target mass reduction amount. Thereby, the discharge capacity of the negative electrode can be increased by the amount of the target capacity increase corresponding to the target mass reduction amount. Thus, according to the above-described negative electrode discharge capacity recovery device, the discharge capacity of the negative electrode can be increased by a desired capacity.

更に、上記の負極放電容量回復装置であって、前記質量測定装置は、前記ニッケル水素蓄電池を充電しながら前記ニッケル水素蓄電池の質量を継続的に測定可能とされてなり、前記放電容量増加手段は、前記質量減少量を継続的に算出する負極放電容量回復装置とすると良い。 Furthermore, in the above negative electrode discharge capacity recovery device, the mass measuring device can continuously measure the mass of the nickel metal hydride storage battery while charging the nickel metal hydride storage battery, and the discharge capacity increasing means includes: A negative electrode discharge capacity recovery device that continuously calculates the mass reduction amount is preferable.

この負極放電容量回復装置では、質量測定装置においてニッケル水素蓄電池の質量を継続的に測定し、放電容量増加手段において質量減少量を継続的に算出しながら、ニッケル水素蓄電池を充電して、負極の放電容量を増加させることができる。これにより、ニッケル水素蓄電池の実際の質量減少量が目標質量減少量に到達したのと同時に、ニッケル水素蓄電池の充電を終了することができる。従って、負極の放電容量を、より正確に目標容量増加量だけ増加させることができる。 In this negative electrode discharge capacity recovery device, the mass of the nickel hydride storage battery is continuously measured by the mass measuring device, and the nickel hydride storage battery is charged while continuously calculating the mass decrease amount by the discharge capacity increasing means. The discharge capacity can be increased. Thereby, the charge of a nickel metal hydride storage battery can be complete | finished simultaneously with the actual mass decrease amount of a nickel metal hydride storage battery having reached the target mass decrease amount. Therefore, the discharge capacity of the negative electrode can be more accurately increased by the target capacity increase amount.

更に、上記のいずれかに記載の負極放電容量回復装置であって、前記安全弁装置を強制的に開弁させる強制開弁装置を備える負極放電容量回復装置とすると良い。 Furthermore, the negative electrode discharge capacity recovery device according to any one of the above may be a negative electrode discharge capacity recovery device including a forced valve opening device that forcibly opens the safety valve device.

この負極放電容量回復装置では、強制開弁装置により安全弁装置の開弁を強制的に行って、充電により発生させた酸素ガスの少なくとも一部を電池外部に排出する。これにより、発生した酸素ガスが水素吸蔵合金に吸蔵された水素と反応して消費される（水が生成される）のを抑制できる。従って、負極の放電容量の容量回復効率を向上させることができる。 In this negative electrode discharge capacity recovery device, the safety valve device is forcibly opened by the forced valve opening device, and at least a part of the oxygen gas generated by charging is discharged outside the battery. Thereby, it can suppress that the generated oxygen gas reacts with the hydrogen occluded by the hydrogen occlusion alloy and is consumed (water is generated). Therefore, the capacity recovery efficiency of the discharge capacity of the negative electrode can be improved.

更に、上記のいずれかに記載の負極放電容量回復装置であって、前記充電回路は、６．０Ｃ以下の充電電流値で前記ニッケル水素蓄電池を充電する負極放電容量回復装置とすると良い。 Furthermore, in the negative electrode discharge capacity recovery device according to any one of the above, the charging circuit may be a negative electrode discharge capacity recovery device that charges the nickel-metal hydride storage battery with a charge current value of 6.0 C or less.

実施形態に係る電池の上面図である。It is a top view of the battery according to the embodiment. 実施形態に係る電池の側面図である。It is a side view of the battery which concerns on embodiment. 実施形態に係る電池の図１におけるＡ−Ａ断面図である。It is AA sectional drawing in FIG. 1 of the battery which concerns on embodiment. 実施形態に係り、安全弁装置の拡大断面図である。It is an expanded sectional view of a safety valve device concerning an embodiment. 実施形態に係り、安全弁装置が開弁したときの様子を示す説明図である。It is explanatory drawing which shows a mode when it concerns on embodiment and a safety valve apparatus opens. 実施形態に係り、出荷時初期の電池における正極容量ＡＥと負極容量ＢＥとの関係を示す説明図である。It is explanatory drawing which concerns on embodiment and shows the relationship between the positive electrode capacity | capacitance AE and the negative electrode capacity | capacitance BE in the battery at the time of shipment. 実施形態に係り、劣化した電池における正極容量ＡＥと負極容量ＢＥとの関係を示す説明図である。It is explanatory drawing which shows the relationship between the positive electrode capacity | capacitance AE and the negative electrode capacity | capacitance BE in the battery which concerns on embodiment. 実施形態に係り、容量回復過程における正極容量ＡＥと負極容量ＢＥとの関係を示す説明図である。It is explanatory drawing which shows the relationship between positive electrode capacity | capacitance AE and negative electrode capacity | capacitance BE in a capacity | capacitance recovery process in connection with embodiment. 実施形態に係り、容量回復後における正極容量ＡＥと負極容量ＢＥとの関係を示す説明図である。It is explanatory drawing which shows the relationship between positive electrode capacity | capacitance AE and negative electrode capacity | capacitance BE after capacity | capacitance recovery concerning embodiment. 実施形態に係る負極放電容量回復装置を示す説明図である。It is explanatory drawing which shows the negative electrode discharge capacity recovery apparatus which concerns on embodiment. 充電により負極の放電容量ＢＤを増加させた電池について、電池の質量減少量ΔＷと負極の放電容量ＢＤの容量増加量ΔＢＤとの関係を示すグラフである。It is a graph which shows the relationship between the battery mass decrease amount ΔW and the capacity increase amount ΔBD of the negative electrode discharge capacity BD for a battery in which the negative electrode discharge capacity BD is increased by charging. 充電により負極の放電容量ＢＤを増加させた電池について、充電開始時の電池温度と負極の放電容量ＢＤの容量回復効率との関係を示すグラフである。It is a graph which shows the relationship between the battery temperature at the time of charge start, and the capacity | capacitance recovery efficiency of the negative electrode discharge capacity BD about the battery which increased the discharge capacity BD of the negative electrode by charge. 充電により負極の放電容量ＢＤを増加させた電池について、充電電流値と負極の放電容量ＢＤの容量回復効率との関係を示すグラフである。It is a graph which shows the relationship between a charging current value and the capacity | capacitance recovery efficiency of the discharge capacity BD of a negative electrode about the battery which increased the discharge capacity BD of the negative electrode by charge. 実施形態に係る負極放電容量回復方法のメインルーチンのフローチャートである。It is a flowchart of the main routine of the negative electrode discharge capacity recovery method which concerns on embodiment. 実施形態に係る負極放電容量回復方法のサブルーチンのフローチャートである。It is a flowchart of the subroutine of the negative electrode discharge capacity recovery method according to the embodiment.

以下、本発明の実施の形態を、図面を参照しつつ説明する。図１〜図３に、本実施形態に係るニッケル水素蓄電池１０（以下、単に電池１０とも言う）を示す。また、図４及び図５に、この電池１０の安全弁装置８０を示す。
この電池１０は、ハイブリッド自動車や電気自動車等の車両などに搭載される角型で密閉型のニッケル水素蓄電池である。この電池１０は、直方体状の電池ケース２０と、この電池ケース２０内に収容された複数（６つ）の電極体３０と、電池ケース２０に支持された正極端子部材６０及び負極端子部材７０等から構成されている（図１〜図３参照）。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. 1 to 3 show a nickel metal hydride storage battery 10 (hereinafter also simply referred to as a battery 10) according to the present embodiment. 4 and 5 show a safety valve device 80 of the battery 10.
The battery 10 is a rectangular and sealed nickel-metal hydride storage battery mounted on a vehicle such as a hybrid vehicle or an electric vehicle. The battery 10 includes a rectangular parallelepiped battery case 20, a plurality (six) of electrode bodies 30 accommodated in the battery case 20, a positive terminal member 60 and a negative terminal member 70 supported by the battery case 20, and the like. (Refer to FIGS. 1 to 3).

このうち電池ケース２０は、樹脂により形成されている。この電池ケース２０は、上側のみ開口した有底角筒状のケース本体２１と、このケース本体２１の開口を封口する矩形板状の蓋部材２３から構成されている。ケース本体２１には、電池ケース２０の内部から外部に延出する形態の正極端子部材６０と負極端子部材７０がそれぞれ固設されている。一方、蓋部材２３には、復帰型の安全弁装置８０が設けられている。 Among these, the battery case 20 is formed of resin. The battery case 20 includes a bottomed rectangular tube-shaped case main body 21 that is open only on the upper side, and a rectangular plate-shaped lid member 23 that seals the opening of the case main body 21. A positive terminal member 60 and a negative terminal member 70 are fixed to the case body 21 so as to extend from the inside of the battery case 20 to the outside. On the other hand, the lid member 23 is provided with a return-type safety valve device 80.

この安全弁装置８０は、ゴム製の安全弁８１を有する（図４及び図３参照）。この安全弁８１は、電池内圧が所定の開弁圧（具体的には０．６ＭＰａ）未満のときは、電池ケース２０の内外を連通する通気孔８３を気密に封止した状態を保っている。一方、図５に示すように、電池内圧が開弁圧に達すると、自動的に開弁して、電池１０（電池ケース２０）内のガスＧＡを通気孔８３を通じて電池外部に排出する。詳細には、電池内圧が開弁圧に達すると、その圧力で安全弁８１の底部８１ｃが電池外部側（図５中、上方）に押し上げられて、通気孔８３の封止が解除される。これにより、電池１０内のガスＧＡが通気孔８３を通じて電池外部に排出される。 The safety valve device 80 includes a rubber safety valve 81 (see FIGS. 4 and 3). When the battery internal pressure is less than a predetermined valve opening pressure (specifically, 0.6 MPa), the safety valve 81 keeps the air hole 83 communicating with the inside and outside of the battery case 20 in an airtight manner. On the other hand, as shown in FIG. 5, when the battery internal pressure reaches the valve opening pressure, the valve is automatically opened, and the gas GA in the battery 10 (battery case 20) is discharged to the outside of the battery through the vent hole 83. Specifically, when the battery internal pressure reaches the valve opening pressure, the bottom 81c of the safety valve 81 is pushed up to the battery external side (upward in FIG. 5) by the pressure, and the sealing of the vent 83 is released. Thereby, the gas GA in the battery 10 is discharged to the outside of the battery through the vent hole 83.

電池ケース２０の内部は、５つの隔壁部２５によって、６つのセル９０に仕切られている（図３参照）。各々のセル９０内には、それぞれ電極体３０が収容されると共に、電解液（図示しない）が保持されている。電極体３０は、正極３１と負極４１と袋状のセパレータ５１から構成されている。正極３１は、袋状のセパレータ５１内に挿入されており、セパレータ５１内に挿入された正極３１と負極４１とが交互に積層されている。各セル９０内に位置する正極３１及び負極４１は、それぞれ集電されて、これらが直列に接続されると共に、前述の正極端子部材６０及び負極端子部材７０に接続されている。正極３１は、水酸化ニッケルを含む活物質と、発泡ニッケルからなる活物質支持体とを有する電極板である。また、負極４１は、水素吸蔵合金を負極構成材として含む電極板である。また、セパレータ５１は、親水化処理された合成繊維からなる不織布である。また、電解液は、ＫＯＨを含む比重１．２〜１．４のアルカリ水溶液である。 The inside of the battery case 20 is partitioned into six cells 90 by five partition walls 25 (see FIG. 3). In each cell 90, the electrode body 30 is accommodated, and an electrolytic solution (not shown) is held. The electrode body 30 includes a positive electrode 31, a negative electrode 41, and a bag-shaped separator 51. The positive electrode 31 is inserted into a bag-shaped separator 51, and the positive electrode 31 and the negative electrode 41 inserted into the separator 51 are alternately stacked. The positive electrode 31 and the negative electrode 41 located in each cell 90 are respectively collected and connected in series, and are connected to the positive electrode terminal member 60 and the negative electrode terminal member 70 described above. The positive electrode 31 is an electrode plate having an active material containing nickel hydroxide and an active material support made of foamed nickel. The negative electrode 41 is an electrode plate containing a hydrogen storage alloy as a negative electrode constituent material. The separator 51 is a non-woven fabric made of synthetic fibers subjected to a hydrophilic treatment. The electrolytic solution is an alkaline aqueous solution having a specific gravity of 1.2 to 1.4 containing KOH.

この電池１０は、各々のセル９０の正極容量ＡＥがＡＥ＝６．５Ａｈ、負極容量ＢＥがＢＥ＝１１．０Ａｈである（図６参照）。なお、図６は、出荷時初期の電池１０（各セル９０）における正極容量ＡＥと負極容量ＢＥとの関係を模式的に示す。この図では、正極容量ＡＥ及び負極容量ＢＥをそれぞれ縦長の帯の長さで表している。 In this battery 10, the positive electrode capacity AE of each cell 90 is AE = 6.5 Ah, and the negative electrode capacity BE is BE = 11.0 Ah (see FIG. 6). FIG. 6 schematically shows the relationship between the positive electrode capacity AE and the negative electrode capacity BE in the battery 10 (each cell 90) at the time of shipment. In this figure, the positive electrode capacity AE and the negative electrode capacity BE are each represented by the length of a vertically long band.

この電池１０は、正極規制の状態であり、各々のセル９０の電池容量（出荷時初期容量）が６．５Ａｈである。即ち、ＳＯＣ（State Of Charge）１００％＝６．５Ａｈである。また、正極３１の充電容量ＡＣ及び放電容量ＡＤは、正極容量ＡＥに等しく、ＡＣ＝ＡＤ＝ＡＥ＝６．５Ａｈである。一方、負極４１の充電容量ＢＣはＢＣ＝８．５Ａｈであり、このうち充電リザーブ容量ＢＣＲはＢＣＲ＝２．０Ａｈである。また、負極４１の放電容量ＢＤはＢＤ＝９．０Ａｈであり、このうち放電リザーブ容量ＢＤＲはＢＤＲ＝２．５Ａｈである。 This battery 10 is in a positive electrode regulation state, and the battery capacity (initial capacity at the time of shipment) of each cell 90 is 6.5 Ah. That is, SOC (State Of Charge) 100% = 6.5 Ah. The charge capacity AC and the discharge capacity AD of the positive electrode 31 are equal to the positive electrode capacity AE, and AC = AD = AE = 6.5 Ah. On the other hand, the charge capacity BC of the negative electrode 41 is BC = 8.5 Ah, among which the charge reserve capacity BCR is BCR = 2.0 Ah. Further, the discharge capacity BD of the negative electrode 41 is BD = 9.0 Ah, and among these, the discharge reserve capacity BDR is BDR = 2.5 Ah.

ここで、負極４１の放電リザーブ容量ＢＤＲの測定方法について説明する。まず出荷時初期の未使用の電池１０を複数用意し、これらの電池１０について、電池電圧が１．０Ｖになるまで放電した後、電池１０内に電解液を補充して電解液が過剰に存在する状態とする。その後、各セル９０内の電解液中にＨｇ／ＨｇＯ参照極（図示しない）を配設して、放電容量を測定しながら各電池１０を過放電させた。そして、次式の基づいて負極４１の放電リザーブ容量ＢＤＲを算出した。
放電リザーブ容量ＢＤＲ＝（参照極の電位に対する負極４１の電位が−０．７Ｖになるまでの放電容量）−（参照極に対する正極３１の電位が−０．５Ｖになるまでの放電容量） Here, a method for measuring the discharge reserve capacity BDR of the negative electrode 41 will be described. First, prepare a plurality of unused batteries 10 at the time of shipment. After these batteries 10 are discharged until the battery voltage reaches 1.0 V, the electrolyte is replenished in the batteries 10 and there is an excess of electrolyte. State Thereafter, an Hg / HgO reference electrode (not shown) was disposed in the electrolyte solution in each cell 90, and each battery 10 was overdischarged while measuring the discharge capacity. Then, the discharge reserve capacity BDR of the negative electrode 41 was calculated based on the following formula.
Discharge reserve capacity BDR = (discharge capacity until the potential of the negative electrode 41 with respect to the potential of the reference electrode becomes −0.7V) − (discharge capacity until the potential of the positive electrode 31 with respect to the reference electrode becomes −0.5V)

その結果、各セル９０の負極４１の放電リザーブ容量ＢＤＲの初期値は、前述のように、平均してＢＤＲ＝２．５Ａｈであった。また、正極容量ＡＥ＝６．５Ａｈであるので、負極４１の放電容量ＢＤは、ＢＤ＝６．５＋２．５＝９．０Ａｈと求められる。また、負極４１の充電容量ＢＣは、ＢＣ＝１１．０−２．５＝８．５Ａｈ、充電リザーブ容量ＢＣＲは、ＢＣＲ＝８．５−６．５＝２．０Ａｈとそれぞれ求められる。 As a result, the initial value of the discharge reserve capacity BDR of the negative electrode 41 of each cell 90 was BDR = 2.5 Ah on average as described above. Further, since the positive electrode capacity AE = 6.5 Ah, the discharge capacity BD of the negative electrode 41 is obtained as BD = 6.5 + 2.5 = 9.0 Ah. Further, the charge capacity BC of the negative electrode 41 is obtained as BC = 11.0-2.5 = 8.5 Ah, and the charge reserve capacity BCR is obtained as BCR = 8.5-6.5 = 2.0 Ah.

（劣化した状態の電池の作製）
次に、負極４１の放電容量ＢＤを強制的に減少させた電池１０を作製する。具体的には、出荷時初期の未使用の電池１０を複数用意し、これらの電池１０について電池ケース２０に穴をあけ、電池ケース２０内に強制的に酸素を注入して、負極４１の放電容量ＢＤを減少させる。なお、電池ケース２０にあけた穴は酸素注入後に閉塞する。 (Production of deteriorated battery)
Next, the battery 10 in which the discharge capacity BD of the negative electrode 41 is forcibly reduced is manufactured. Specifically, a plurality of unused batteries 10 at the time of shipment are prepared, a hole is made in the battery case 20 for these batteries 10, oxygen is forcibly injected into the battery case 20, and the negative electrode 41 is discharged. The capacity BD is decreased. Note that the hole formed in the battery case 20 is closed after oxygen injection.

その後、これらの電池１０について、各セル９０の負極４１の放電容量ＢＤを調査したところ、放電リザーブ容量ＢＤＲは無くなっており（ＢＤＲ＝零）、放電容量ＢＤが平均して初期の９．０Ａｈから５．５Ａｈ減ってＢＤ＝３．５Ａｈであった（図７参照）。従って、この高温放置により劣化させた電池１０は、負極規制の状態にあり、各々のセル９０の電池容量が、初期の６．５Ａｈから３．０Ａｈ減って３．５Ａｈであった。 Thereafter, when the discharge capacity BD of the negative electrode 41 of each cell 90 was examined for these batteries 10, the discharge reserve capacity BDR was lost (BDR = zero), and the discharge capacity BD averaged from the initial 9.0 Ah. It decreased by 5.5 Ah and BD = 3.5 Ah (see FIG. 7). Therefore, the battery 10 deteriorated by being left at a high temperature is in a state of negative electrode regulation, and the battery capacity of each cell 90 is 3.5 Ah, which is 3.0 Ah lower than the initial 6.5 Ah.

（負極放電容量回復試験１）
次に、上述の劣化させた（負極４１の放電容量ＢＤを減少させた）電池１０を複数（１４個）用意し、これらについて、負極４１の放電容量ＢＤを増加（回復）させる負極放電容量回復試験を行った。具体的には、各電池１０を充電（本試験では過充電）して正極３１から酸素ガスを発生させ、その少なくとも一部を、開弁した安全弁装置８０を通じて電池外部に排出して、負極４１の放電容量ＢＤを増加させた。 (Negative electrode discharge capacity recovery test 1)
Next, a plurality (14 pieces) of the above-described deteriorated batteries 10 (in which the discharge capacity BD of the negative electrode 41 is reduced) are prepared, and the negative electrode discharge capacity recovery in which the discharge capacity BD of the negative electrode 41 is increased (recovered). A test was conducted. Specifically, each battery 10 is charged (in this test, overcharged) to generate oxygen gas from the positive electrode 31, and at least a part thereof is discharged to the outside of the battery through the opened safety valve device 80, and the negative electrode 41 The discharge capacity BD was increased.

電池１０は、ＳＯＣがある程度高い状態（概ね３０％以上）では、充電すると、次の反応が生じる。なお、「Ｍ」は、水素吸蔵合金を示す。
（正極）ＯＨ^- → 1/4Ｏ₂＋1/2Ｈ₂Ｏ＋ｅ^- …（１）
（負極）Ｍ＋Ｈ₂Ｏ＋ｅ^- → ＭＨ＋ＯＨ^-…（２）
ＭＨ＋1/4Ｏ₂→ Ｍ＋1/2Ｈ₂Ｏ …（３） When the battery 10 is charged in a state where the SOC is somewhat high (approximately 30% or more), the following reaction occurs when charged. “M” represents a hydrogen storage alloy.
(Positive electrode) OH ⁻ → 1/4 O ₂ + 1 / 2H ₂ O + e ⁻ (1)
(Negative electrode) M + H ₂ O + e ⁻ → MH + OH ⁻ (2)
MH + 1 / 4O ₂ → M + 1 / 2H ₂ O (3)

式（１）の正極３１から発生した酸素ガスＯ₂の少なくとも一部を、開弁した安全弁装置８０を通じて電池外部に排出すると、負極４１では、式（２）の反応が進行して水素Ｈが吸蔵される一方、式（３）の反応が抑制されるので、水素Ｈの放出が抑制される。従って、電池１０を充電すると、図８に破線のハッチングで模式的に示すように、負極４１の充電部分の容量が増加する。その結果、負極４１の放電容量ＢＤを増加させることができる（図９参照）。
なお、これら図８及び図９に示した例では、負極４１に充電リザーブ容量ＢＣＲが再び生じるまで、具体的には、放電リザーブ容量ＢＤＲが出荷時初期と同じＢＤＲ＝２．５Ａｈに回復するまで、放電容量ＢＤをＢＤ＝３．５Ａｈから５．５Ａｈ増加させてＢＤ＝９．０Ａｈとした場合を示している。なお、図８及び図９では、正極３１及び負極４１の充電部分の容量をハッチングで示している。 When at least a part of the oxygen gas O ₂ generated from the positive electrode 31 of the formula (1) is discharged to the outside of the battery through the opened safety valve device 80, the reaction of the formula (2) proceeds in the negative electrode 41 to generate hydrogen H. On the other hand, since the reaction of the formula (3) is suppressed, the release of hydrogen H is suppressed. Accordingly, when the battery 10 is charged, the capacity of the charged portion of the negative electrode 41 increases as schematically shown by the broken line hatching in FIG. As a result, the discharge capacity BD of the negative electrode 41 can be increased (see FIG. 9).
In the examples shown in FIGS. 8 and 9, until the charge reserve capacity BCR is generated again in the negative electrode 41, specifically, until the discharge reserve capacity BDR is restored to the same BDR = 2.5 Ah as in the initial shipment. In this case, the discharge capacity BD is increased by 5.5 Ah from BD = 3.5 Ah to BD = 9.0 Ah. 8 and 9, the capacities of the charged portions of the positive electrode 31 and the negative electrode 41 are indicated by hatching.

この負極放電容量回復試験は、図１０に示す負極放電容量回復装置１００を用いて行った。この負極放電容量回復装置１００は、充電回路１２０及び充電制御装置１３０を有する充電装置１１０と、質量測定装置１４０と、強制開弁装置１５０と、ガス流量計１６０とを備える。
このうち充電回路１２０は、接続ケーブル１２１，１２３を通じて、電池１０の正極端子部材６０及び負極端子部材７０に接続されている。これにより、充電回路１２０によって電池１０を充電できる。 This negative electrode discharge capacity recovery test was performed using a negative electrode discharge capacity recovery device 100 shown in FIG. The negative electrode discharge capacity recovery device 100 includes a charging device 110 having a charging circuit 120 and a charging control device 130, a mass measuring device 140, a forced valve opening device 150, and a gas flow meter 160.
Among these, the charging circuit 120 is connected to the positive electrode terminal member 60 and the negative electrode terminal member 70 of the battery 10 through connection cables 121 and 123. Thereby, the battery 10 can be charged by the charging circuit 120.

充電制御装置１３０は、充電回路１２０と接続されており、この充電制御装置１３０によって、充電回路１２０による電池１０の充電を制御できる。この充電制御装置１３０は、ＣＰＵ、ＲＯＭ、ＲＡＭ、入出力回路等から構成されるマイクロコンピュータであり、所定のプログラムにより駆動される。
質量測定装置１４０は、電子天秤であり、電池１０の質量（回復前の初期の質量Ｗａ及び現在の質量Ｗｂ）を測定できる。この質量測定装置１４０は、充電装置１１０の充電制御装置１３０に接続されており、電池１０を充電している間も電池１０の現在の質量Ｗｂを継続的に測定して、その質量情報を充電制御装置１３０に送信できる。 The charging control device 130 is connected to the charging circuit 120, and the charging control device 130 can control charging of the battery 10 by the charging circuit 120. The charging control device 130 is a microcomputer including a CPU, a ROM, a RAM, an input / output circuit, and the like, and is driven by a predetermined program.
The mass measuring device 140 is an electronic balance, and can measure the mass of the battery 10 (initial mass Wa before recovery and current mass Wb). The mass measuring device 140 is connected to the charging control device 130 of the charging device 110, and continuously measures the current mass Wb of the battery 10 while charging the battery 10, and charges the mass information. It can be transmitted to the control device 130.

強制開弁装置１５０は、電池内圧が開弁圧（具体的には０．６ＭＰａ）に達するよりも前に安全弁装置８０を強制的に開弁させることが可能な装置である。この強制開弁装置１５０は、真空ポンプ１５１とこれに接続された連結ホース１５３とを有する。連結ホース１５３は、他方で電池１０の安全弁装置８０に気密に装着されている。これにより、真空ポンプ１５１を作動させると、安全弁装置８０の電池外部側に掛かる気圧を低くできるので、電池内圧が開弁圧に達するよりも前に、安全弁装置８０を開弁させることができる。そして、充電により正極３１から発生した酸素ガスの少なくとも一部を、安全弁装置８０の通気孔８３を通じて電池外部に排出する。この排出した酸素ガス等のガスＧＡは、次述するガス流量計１６０によって検知される。 The forced valve opening device 150 is a device that can forcibly open the safety valve device 80 before the battery internal pressure reaches the valve opening pressure (specifically, 0.6 MPa). The forced valve opening device 150 includes a vacuum pump 151 and a connecting hose 153 connected thereto. On the other hand, the connecting hose 153 is airtightly attached to the safety valve device 80 of the battery 10. Thereby, when the vacuum pump 151 is operated, the atmospheric pressure applied to the outside of the battery of the safety valve device 80 can be lowered. Therefore, the safety valve device 80 can be opened before the battery internal pressure reaches the valve opening pressure. Then, at least a part of the oxygen gas generated from the positive electrode 31 by charging is discharged outside the battery through the vent hole 83 of the safety valve device 80. The discharged gas GA such as oxygen gas is detected by a gas flow meter 160 described below.

ガス流量計１６０は、真空ポンプ１５１と安全弁装置８０との間に配置されている。これにより、ガス流量計１６０によって、開弁した安全弁装置８０を通じて電池外部に排出されたガスＧＡを検知できる。このガス流量計１６０は、充電装置１１０の充電制御装置１３０に接続されており、その検知情報を充電制御装置１３０に送信できる。 The gas flow meter 160 is disposed between the vacuum pump 151 and the safety valve device 80. As a result, the gas flow meter 160 can detect the gas GA discharged to the outside of the battery through the opened safety valve device 80. The gas flow meter 160 is connected to the charging control device 130 of the charging device 110 and can transmit the detection information to the charging control device 130.

この負極放電容量回復試験では、上述の負極放電容量回復装置１００を用いて、前述の強制劣化させた（負極４１の放電容量ＢＤを減少させた）１４個の電池１０について、様々な条件で、充電により負極４１の放電容量ＢＤを増加させた。即ち、充電開始時の電池温度を、０℃、２５℃または３０℃のいずれかとした。具体的には、３個の電池１０については充電開始時の電池温度を０℃とし、８個の電池１０については充電開始時の電池温度を２５℃とし、３個の電池１０については充電開始時の電池温度を３０℃とした。なお、充電電流値は、いずれの電池１０についても３．０Ｃの一定電流値とした。 In this negative electrode discharge capacity recovery test, using the above-described negative electrode discharge capacity recovery device 100, for the 14 batteries 10 that were forcibly deteriorated (the discharge capacity BD of the negative electrode 41 was reduced) under various conditions, The discharge capacity BD of the negative electrode 41 was increased by charging. That is, the battery temperature at the start of charging was set to 0 ° C., 25 ° C., or 30 ° C. Specifically, the battery temperature at the start of charging is set to 0 ° C. for the three batteries 10, the battery temperature at the start of charging is set to 25 ° C. for the eight batteries 10, and charging is started for the three batteries 10. The battery temperature was 30 ° C. The charging current value was a constant current value of 3.0 C for any of the batteries 10.

試験後の各電池１０について、試験前後の電池１０の質量減少量ΔＷ（ｇ）、即ち、試験開始前の電池１０の質量Ｗａ（ｇ）と試験後の電池１０の質量Ｗｂ（ｇ）との差分ΔＷ＝Ｗａ−Ｗｂにより、質量減少量ΔＷをそれぞれ算出した。また、試験後の各電池１０について、負極４１の放電容量ＢＤを測定し、試験前後の放電容量ＢＤの容量増加量ΔＢＤ（Ａｈ）をそれぞれ求めた。その結果を図１１に示す。
なお、図１１では、充電開始時の電池温度を０℃とした電池の結果を「○」、充電開始時の電池温度を２５℃とした電池の結果を「△」、充電開始時の電池温度を３０℃とした電池の結果を「□」で示してある。 For each battery 10 after the test, the mass decrease amount ΔW (g) of the battery 10 before and after the test, that is, the mass Wa (g) of the battery 10 before the start of the test and the mass Wb (g) of the battery 10 after the test. The mass reduction amount ΔW was calculated from the difference ΔW = Wa−Wb. Further, for each battery 10 after the test, the discharge capacity BD of the negative electrode 41 was measured, and the capacity increase amount ΔBD (Ah) of the discharge capacity BD before and after the test was obtained. The result is shown in FIG.
In FIG. 11, the result of the battery with the battery temperature at 0 ° C. at the start of charging is “◯”, the result of the battery with the battery temperature at 25 ° C. at the start of charging is “Δ”, and the battery temperature at the start of charging. The result of the battery at 30 ° C. is indicated by “□”.

図１１から明らかなように、負極放電容量回復試験において、電池１０の質量減少量ΔＷと負極４１の放電容量ＢＤの容量増加量ΔＢＤとの間には、高い相関、具体的には比例関係があることが判る。得られたデータを最小二乗法により一次近似したところ、ΔＢＤ＝０．６８×ΔＷという相関式が得られた。この相関により、電池１０の質量減少量ΔＷをどれだけにすれば、負極４１の放電容量ＢＤの容量増加量ΔＢＤがどれだけになるかが判る。換言すれば、容量増加量ΔＢＤの目標値（目標容量増加量ＢＤｔ）を達成するためには、電池１０の質量減少量ΔＷをどれだけにすれば良いかが判る。例えば、容量増加量ΔＢＤの目標容量増加量ＢＤｔをＢＤｔ＝５．５Ａｈに設定した場合、これを達成するためには、電池１０の質量減少量ΔＷがΔＷ＝８．１ｇとなるまで充電を行えば良いことが判る。 As is clear from FIG. 11, in the negative electrode discharge capacity recovery test, there is a high correlation, specifically, a proportional relationship between the mass decrease amount ΔW of the battery 10 and the capacity increase amount ΔBD of the discharge capacity BD of the negative electrode 41. I know that there is. When the obtained data was linearly approximated by the method of least squares, a correlation equation ΔBD = 0.68 × ΔW was obtained. From this correlation, it can be determined how much the amount of mass decrease ΔW of the battery 10 is, and how much the amount of increase in capacity ΔBD of the discharge capacity BD of the negative electrode 41 is. In other words, in order to achieve the target value of the capacity increase amount ΔBD (target capacity increase amount BDt), it can be seen how much the mass decrease amount ΔW of the battery 10 should be. For example, when the target capacity increase amount BDt of the capacity increase amount ΔBD is set to BDt = 5.5 Ah, in order to achieve this, charging is performed until the mass decrease amount ΔW of the battery 10 reaches ΔW = 8.1 g. It turns out that it is good.

（負極放電容量回復試験２）
次に、前述の強制劣化させた（負極４１の放電容量ＢＤを減少させた）電池１０を５個用意し、これらについて、充電開始時の電池温度を−３０℃、０℃、２５℃、３０℃または３５℃として、充電（本試験では過充電）により負極４１の放電容量ＢＤを増加させる負極放電容量回復試験を行った。なお、充電電流値は、いずれの電池１０についても３．０Ｃの一定電流値とした。
また、試験後の各電池１０について、負極４１の放電容量ＢＤの容量回復効率（Ａｈ／ｇ）をそれぞれ求めた。ここで言う容量回復効率（Ａｈ／ｇ）とは、質量減少量（ｇ）と容量増加量（Ａｈ）の割合である。 (Negative electrode discharge capacity recovery test 2)
Next, five batteries 10 having the above-described forced deterioration (in which the discharge capacity BD of the negative electrode 41 is decreased) are prepared, and the battery temperatures at the start of charging are −30 ° C., 0 ° C., 25 ° C., 30 A negative electrode discharge capacity recovery test was performed in which the discharge capacity BD of the negative electrode 41 was increased by charging (overcharge in this test) at 35 ° C. or 35 ° C. The charging current value was a constant current value of 3.0 C for any of the batteries 10.
For each battery 10 after the test, the capacity recovery efficiency (Ah / g) of the discharge capacity BD of the negative electrode 41 was determined. The capacity recovery efficiency (Ah / g) referred to here is the ratio between the mass decrease amount (g) and the capacity increase amount (Ah).

図１２から明らかなように、負極放電容量回復試験において、充電開始時の電池温度を３０℃以下とすると、負極４１の放電容量ＢＤの容量回復効率を高くできることが判る。一方、充電開始時の電池温度が３０℃を越えると、容量回復効率が低下することが判る。従って、負極放電容量回復試験は、充電開始時の電池温度を３０℃以下にして行うのが好ましい。 As apparent from FIG. 12, in the negative electrode discharge capacity recovery test, it can be seen that the capacity recovery efficiency of the discharge capacity BD of the negative electrode 41 can be increased if the battery temperature at the start of charging is 30 ° C. or lower. On the other hand, it can be seen that when the battery temperature at the start of charging exceeds 30 ° C., the capacity recovery efficiency decreases. Therefore, the negative electrode discharge capacity recovery test is preferably performed at a battery temperature of 30 ° C. or less at the start of charging.

（負極放電容量回復試験３）
次に、前述の強制劣化させた（負極４１の放電容量ＢＤを減少させた）電池１０を４個用意し、これらについて、充電電流値を１．５Ｃ、３．０Ｃ、５．４Ｃまたは７．７Ｃの一定電流値として、充電（本試験では過充電）により負極４１の放電容量ＢＤを増加させる負極放電容量回復試験を行った。なお、充電開始時の電池温度は、いずれの電池１０についても２５℃とした。 (Negative electrode discharge capacity recovery test 3)
Next, four batteries 10 having the above-described forced deterioration (in which the discharge capacity BD of the negative electrode 41 is reduced) are prepared, and the charging current value of these batteries 10 is 1.5C, 3.0C, 5.4C, or 7. As a constant current value of 7 C, a negative electrode discharge capacity recovery test was performed in which the discharge capacity BD of the negative electrode 41 was increased by charging (overcharge in this test). The battery temperature at the start of charging was 25 ° C. for any of the batteries 10.

また、試験後の各電池１０について、前述のように、負極４１の放電容量ＢＤの容量回復効率（Ａｈ／ｇ）をそれぞれ求めた。その結果を図１３に示す。
図１３から明らかなように、負極放電容量回復試験において、充電電流値を６．０Ｃ以下にすると、負極４１の放電容量ＢＤの容量回復効率を高くできることが判る。一方、充電電流値が６．０Ｃを越えると、容量回復効率が低下することが判る。従って、負極放電容量回復試験は、充電電流値を６．０Ｃ以下にして行うのが好ましい。 For each battery 10 after the test, the capacity recovery efficiency (Ah / g) of the discharge capacity BD of the negative electrode 41 was determined as described above. The result is shown in FIG.
As can be seen from FIG. 13, in the negative electrode discharge capacity recovery test, the capacity recovery efficiency of the discharge capacity BD of the negative electrode 41 can be increased when the charging current value is 6.0 C or less. On the other hand, it can be seen that when the charging current value exceeds 6.0 C, the capacity recovery efficiency decreases. Therefore, the negative electrode discharge capacity recovery test is preferably performed at a charging current value of 6.0 C or less.

以上の試験結果より、以下のようにすれば、負極４１の放電容量ＢＤを所望の容量（目標容量増加量ＢＤｔ）だけ増加させることができる。具体的には、まず負極４１の放電容量ＢＤについて目標容量増加量ＢＤｔを設定する（例えば目標容量増加量ＢＤｔ＝５．５Ａｈに設定する）。
次に、回復前後の電池１０の質量減少量ΔＷと負極４１の放電容量ＢＤの容量増加量ΔＢＤとの相関（具体的には、ΔＢＤ＝０．６８×ΔＷ）に基づいて、設定された目標容量増加量ＢＤｔに対応する目標質量減少量Ｗｔを設定する（例えば目標容量増加量ＢＤｔ＝５．５Ａｈとした場合には、目標質量減少量ＷｔをＷｔ＝８．１ｇに設定する）。 From the above test results, the discharge capacity BD of the negative electrode 41 can be increased by a desired capacity (target capacity increase amount BDt) as follows. Specifically, first, the target capacity increase amount BDt is set for the discharge capacity BD of the negative electrode 41 (for example, the target capacity increase amount BDt is set to 5.5 Ah).
Next, the target set based on the correlation (specifically, ΔBD = 0.68 × ΔW) between the mass decrease amount ΔW of the battery 10 before and after the recovery and the capacity increase amount ΔBD of the discharge capacity BD of the negative electrode 41. A target mass decrease amount Wt corresponding to the capacity increase amount BDt is set (for example, when the target capacity increase amount BDt = 5.5 Ah, the target mass decrease amount Wt is set to Wt = 8.1 g).

次に、電池１０を充電して正極３１から酸素ガスを発生させ、その少なくとも一部を、開弁した安全弁装置８０を通じて電池外部に排出して、負極４１の放電容量ＢＤを増加させる。具体的には、質量減少量ΔＷが目標質量減少量Ｗｔ（例えばＷｔ＝８．１ｇ）に達するまで、電池１０を充電する。その際、充電開始時の電池温度を３０℃以下にし、また、充電電流値を６．０Ｃ以下にするのが好ましい。これにより、設定した目標容量増加量ＢＤｔ(例えばＢＤｔ＝５．５Ａｈ）の分だけ、負極４１の放電容量ＢＤを増加（回復）させることができる。以下に、具体例を説明する。 Next, the battery 10 is charged to generate oxygen gas from the positive electrode 31, and at least a part thereof is discharged to the outside of the battery through the opened safety valve device 80 to increase the discharge capacity BD of the negative electrode 41. Specifically, the battery 10 is charged until the mass reduction amount ΔW reaches a target mass reduction amount Wt (for example, Wt = 8.1 g). At that time, the battery temperature at the start of charging is preferably 30 ° C. or lower, and the charging current value is preferably 6.0 C or lower. Thereby, the discharge capacity BD of the negative electrode 41 can be increased (recovered) by the set target capacity increase amount BDt (for example, BDt = 5.5 Ah). A specific example will be described below.

（実施例）
次いで、本実施形態に係る負極放電容量回復装置１００を用いた負極放電容量回復方法について、図１４及び図１５を参照しつつ説明する。この負極放電容量回復方法を行うにあたり、図１１に示した回復前後の電池１０の質量減少量ΔＷと負極４１の放電容量ＢＤの容量増加量ΔＢＤとの相関（具体的には、ΔＢＤ＝０．６８×ΔＷ）を、予め把握しておく。 (Example)
Next, a negative electrode discharge capacity recovery method using the negative electrode discharge capacity recovery device 100 according to the present embodiment will be described with reference to FIGS. 14 and 15. In performing this negative electrode discharge capacity recovery method, the correlation between the mass decrease amount ΔW of the battery 10 before and after recovery shown in FIG. 11 and the capacity increase amount ΔBD of the discharge capacity BD of the negative electrode 41 (specifically, ΔBD = 0. 68 × ΔW) is grasped in advance.

次に、前述のように負極４１の放電容量ＢＤが減少した電池１０を用意し、この電池１０を前述の負極放電容量回復装置１００にセットする。具体的には、電池１０を質量測定装置１４０の上に載置する。また、接続ケーブル１２１，１２３により、電池１０の正極端子部材６０及び負極端子部材７０を充電装置１１０の充電回路１２０に接続する。更に、強制開弁装置１５０の連結ホース１５３を電池１０の安全弁装置８０に接続する。 Next, the battery 10 in which the discharge capacity BD of the negative electrode 41 is reduced as described above is prepared, and this battery 10 is set in the negative electrode discharge capacity recovery device 100 described above. Specifically, the battery 10 is placed on the mass measuring device 140. Moreover, the positive terminal member 60 and the negative terminal member 70 of the battery 10 are connected to the charging circuit 120 of the charging device 110 by the connection cables 121 and 123. Further, the connecting hose 153 of the forced valve opening device 150 is connected to the safety valve device 80 of the battery 10.

そして、図１４に示すように、まずステップＳ１の増加量設定ステップにおいて、負極４１の放電容量ＢＤについて目標容量増加量ＢＤｔを設定する。例えば、目標容量増加量ＢＤｔ＝５．５Ａｈに設定する。なお、このステップＳ１を実行する充電制御装置１３０が前述の「増加量設定手段」に相当する。 Then, as shown in FIG. 14, first, in the increase amount setting step of step S1, a target capacity increase amount BDt is set for the discharge capacity BD of the negative electrode 41. For example, the target capacity increase amount BDt is set to 5.5 Ah. The charge control device 130 that executes step S1 corresponds to the above-described “increase amount setting means”.

次に、ステップＳ２の質量減少量設定ステップにおいて、回復前後の電池１０の質量減少量ΔＷと負極４１の放電容量ＢＤの容量増加量ΔＢＤとの相関に基づいて、設定された目標容量増加量ＢＤｔに対応する目標質量減少量Ｗｔを設定する。具体的には、質量減少量ΔＷと容量増加量ΔＢＤは、ΔＢＤ＝０．６８×ΔＷの関係にあるので、目標容量増加量ＢＤｔ＝５．５Ａｈとすると、目標質量減少量ＷｔはＷｔ＝８．１ｇと算出される。従って、この値を目標質量減少量Ｗｔに設定する。なお、このステップＳ２を実行する充電制御装置１３０が前述の「質量減少量設定手段」に相当する。 Next, in the mass decrease amount setting step of step S2, the set target capacity increase amount BDt is set based on the correlation between the mass decrease amount ΔW of the battery 10 before and after recovery and the capacity increase amount ΔBD of the discharge capacity BD of the negative electrode 41. The target mass reduction amount Wt corresponding to is set. Specifically, since the mass decrease amount ΔW and the capacity increase amount ΔBD are in a relationship of ΔBD = 0.68 × ΔW, when the target capacity increase amount BDt = 5.5 Ah, the target mass decrease amount Wt is Wt = 8. Calculated as 0.1 g. Therefore, this value is set as the target mass reduction amount Wt. The charge control device 130 that executes step S2 corresponds to the above-described “mass reduction amount setting means”.

次に、ステップＳ３の放電容量増加ステップを行う。このステップＳ３では、電池１０を充電（本実施例では過充電）して正極３１から酸素ガスを発生させ、その少なくとも一部を、開弁した安全弁装置８０を通じて電池外部に排出して、負極４１の放電容量ＢＤを増加させる。電池１０の充電は、電池１０の質量減少量ΔＷが前述の目標質量減少量Ｗｔ（＝８．１ｇ）に達するまで行う。なお、このステップＳ３を実行する充電制御装置１３０が前述の「放電容量増加手段」に相当する。 Next, the discharge capacity increasing step of step S3 is performed. In this step S3, the battery 10 is charged (in this embodiment, overcharged) to generate oxygen gas from the positive electrode 31, and at least a part thereof is discharged to the outside of the battery through the opened safety valve device 80, and the negative electrode 41 The discharge capacity BD is increased. The battery 10 is charged until the mass decrease amount ΔW of the battery 10 reaches the target mass decrease amount Wt (= 8.1 g). The charge control device 130 that executes step S3 corresponds to the “discharge capacity increasing means” described above.

具体的には、図１５に示すサブルーチンに進み、ステップＳ３１において、質量測定装置１４０により電池１０の質量（回復前の質量）Ｗａ（ｇ）を測定する。
次に、ステップＳ３２に進み、充電装置１１０により電池１０の充電（過充電）を開始する。その際、本実施例では、充電開始時の電池１０の温度を２５℃とする。また、充電電流値を３．０Ｃの一定電流値とする。
次に、ステップＳ３３において、再び質量測定装置１４０により電池１０の現在の質量Ｗｂ（ｇ）を測定する。次に、ステップＳ３４に進み、現在の質量減少量ΔＷ（ｇ）を算出する。具体的には、ΔＷ＝Ｗａ−Ｗｂにより質量減少量ΔＷを算出する。 Specifically, the process proceeds to a subroutine shown in FIG. 15. In step S31, the mass measuring device 140 measures the mass (mass before recovery) Wa (g) of the battery 10.
Next, it progresses to step S32 and charging of the battery 10 by the charging device 110 (overcharge) is started. At this time, in this embodiment, the temperature of the battery 10 at the start of charging is set to 25 ° C. The charging current value is a constant current value of 3.0C.
Next, in step S33, the current mass Wb (g) of the battery 10 is measured again by the mass measuring device 140. Next, it progresses to step S34 and the present mass reduction amount (DELTA) W (g) is calculated. Specifically, the mass reduction amount ΔW is calculated by ΔW = Wa−Wb.

次に、ステップＳ３５に進み、現在の質量減少量ΔＷが目標質量減少量Ｗｔに達したか否かを判断する。ここで、ＹＥＳ、即ち、質量減少量ΔＷが目標質量減少量Ｗｔに達したと判断された場合には、ステップＳ３７に進み、充電(過充電)を終了する。一方、ＮＯ、即ち、質量減少量ΔＷがまだ目標質量減少量Ｗｔに達していないと判断された場合には、ステップＳ３３に戻って、再び電池１０の質量Ｗｂを測定する。かくして、負極４１の放電容量ＢＤを、設定された目標容量増加量ＢＤｔだけ増加（回復）させることができる。 Next, the process proceeds to step S35, and it is determined whether or not the current mass reduction amount ΔW has reached the target mass reduction amount Wt. Here, if YES, that is, if it is determined that the mass decrease amount ΔW has reached the target mass decrease amount Wt, the process proceeds to step S37, and charging (overcharge) is terminated. On the other hand, if NO, that is, if it is determined that the mass decrease amount ΔW has not yet reached the target mass decrease amount Wt, the process returns to step S33, and the mass Wb of the battery 10 is measured again. Thus, the discharge capacity BD of the negative electrode 41 can be increased (recovered) by the set target capacity increase amount BDt.

以上で説明したように、負極４１の放電容量ＢＤを増加（回復）させるにあたり、回復前後の電池１０の質量減少量ΔＷと負極４１の放電容量ＢＤの容量増加量ΔＢＤとの相関を、予め把握しておく。そして、まず負極４１の放電容量ＢＤについて目標容量増加量ＢＤｔを設定する（容量増加量設定ステップＳ１）。更に、電池１０の質量減少量ΔＷと負極４１の容量増加量ΔＢＤとの相関に基づいて、設定された目標容量増加量Ｂｄｔに対応する目標質量減少量Ｗｔを設定する（質量減少量設定ステップＳ２）。 As described above, in increasing (recovering) the discharge capacity BD of the negative electrode 41, the correlation between the mass decrease amount ΔW of the battery 10 before and after recovery and the capacity increase amount ΔBD of the discharge capacity BD of the negative electrode 41 is grasped in advance. Keep it. First, a target capacity increase amount BDt is set for the discharge capacity BD of the negative electrode 41 (capacity increase amount setting step S1). Further, based on the correlation between the mass decrease amount ΔW of the battery 10 and the capacity increase amount ΔBD of the negative electrode 41, a target mass decrease amount Wt corresponding to the set target capacity increase amount Bdt is set (mass decrease amount setting step S2). ).

その後、電池１０を充電して、負極４１の放電容量ＢＤを増加させる（放電容量増加ステップＳ３）。具体的には、電池１０の質量減少量ΔＷが目標質量減少量Ｗｔに達するまで、電池１０の充電を行う。これにより、目標質量減少量Ｗｔに対応する目標容量増加量ＢＤｔの分だけ、負極４１の放電容量ＢＤを増加させることができる。このように負極放電容量回復装置１００を用いた負極放電容量回復方法によれば、負極４１の放電容量ＢＤを所望の容量増加させることができる。 Thereafter, the battery 10 is charged to increase the discharge capacity BD of the negative electrode 41 (discharge capacity increase step S3). Specifically, the battery 10 is charged until the mass decrease amount ΔW of the battery 10 reaches the target mass decrease amount Wt. Accordingly, the discharge capacity BD of the negative electrode 41 can be increased by the target capacity increase amount BDt corresponding to the target mass decrease amount Wt. Thus, according to the negative electrode discharge capacity recovery method using the negative electrode discharge capacity recovery device 100, the discharge capacity BD of the negative electrode 41 can be increased by a desired capacity.

更に、前述の負極放電容量回復方法では、電池１０の質量Ｗｂを継続的に測定し質量減少量ΔＷを継続的に算出しながら、放電容量増加ステップＳ３を行っている。これにより、電池１０の実際の質量減少量ΔＷが目標質量減少量Ｗｔに到達したのと同時に、放電容量増加ステップＳ３を終了することができる。従って、負極４１の放電容量ＢＤを、より正確に目標容量増加量ＢＤｔだけ増加させることができる。 Further, in the above-described negative electrode discharge capacity recovery method, the discharge capacity increase step S3 is performed while continuously measuring the mass Wb of the battery 10 and continuously calculating the mass decrease amount ΔW. Thereby, discharge capacity increase step S3 can be complete | finished simultaneously with the actual mass decrease amount (DELTA) W of the battery 10 having reached the target mass decrease amount Wt. Therefore, the discharge capacity BD of the negative electrode 41 can be more accurately increased by the target capacity increase amount BDt.

また、前述の負極放電容量回復方法では、安全弁装置８０の開弁を強制的に行って、充電により発生させた酸素ガスの少なくとも一部を電池外部に排出する。これにより、発生した酸素ガスが水素吸蔵合金に吸蔵された水素と反応して消費される（水が生成される）のを抑制できる。従って、負極４１の放電容量ＢＤの容量回復効率を向上させることができる。
また、放電容量増加ステップＳ３は、充電開始時の電池１０の温度を３０℃以下にして行っているので、負極４１の放電容量ＢＤの容量回復効率を向上させることができる。また、この放電容量増加ステップＳ３は、充電電流値を６．０Ｃ以下にして行っているので、負極４１の放電容量ＢＤの容量回復効率を向上させることができる。 In the negative electrode discharge capacity recovery method described above, the safety valve device 80 is forcibly opened to discharge at least a part of the oxygen gas generated by charging to the outside of the battery. Thereby, it can suppress that the generated oxygen gas reacts with the hydrogen occluded by the hydrogen occlusion alloy and is consumed (water is generated). Therefore, the capacity recovery efficiency of the discharge capacity BD of the negative electrode 41 can be improved.
In addition, since the discharge capacity increasing step S3 is performed with the temperature of the battery 10 at the start of charging being 30 ° C. or lower, the capacity recovery efficiency of the discharge capacity BD of the negative electrode 41 can be improved. In addition, since the discharge capacity increasing step S3 is performed with the charging current value set to 6.0 C or less, the capacity recovery efficiency of the discharge capacity BD of the negative electrode 41 can be improved.

以上において、本発明を実施形態に即して説明したが、本発明は上述の実施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で、適宜変更して適用できることは言うまでもない。
例えば、実施形態では、樹脂製の電池ケース２０を備える電池１０を対象にして、負極４１の放電容量ＢＤを増加（回復）させたが、電池ケースが樹脂以外の材質からなるニッケル水素蓄電池についても同様に、負極の放電容量を増加させることができる。 In the above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the above-described embodiment, and it is needless to say that the present invention can be appropriately modified and applied without departing from the gist thereof.
For example, in the embodiment, the discharge capacity BD of the negative electrode 41 is increased (recovered) for the battery 10 including the resin battery case 20, but the nickel hydride storage battery whose battery case is made of a material other than resin is also used. Similarly, the discharge capacity of the negative electrode can be increased.

また、実施形態では、電池１０を過充電することによって正極３１から酸素ガスを発生させているが、充電により正極３１から酸素ガスを発生させ、その少なくとも一部を安全弁装置８０を通じて電池外部に排出できればよく、ＳＯＣ１００％以下（好ましくはＳＯＣ７０％以上）の状態から電池１０の充電を行ってもよい。この場合でも同様に、負極４１の放電容量ＢＤを回復させる効果を得ることができるからである。 In the embodiment, oxygen gas is generated from the positive electrode 31 by overcharging the battery 10, but oxygen gas is generated from the positive electrode 31 by charging, and at least a part thereof is discharged to the outside of the battery through the safety valve device 80. The battery 10 may be charged from a state where the SOC is 100% or less (preferably SOC 70% or more). This is because the effect of recovering the discharge capacity BD of the negative electrode 41 can be obtained in this case as well.

また、実施形態では、負極４１に放電リザーブ容量ＢＤＲが再び生じるまで、具体的には、回復前は零であった放電リザーブ容量ＢＤＲが、出荷時初期と同じＢＤＲ＝２．５Ａｈに回復するまで、放電容量ＢＤを回復前のＢＤ＝３．５Ａｈから５．５Ａｈ増加させてＢＤ＝９．０Ａｈとした場合を示したが、これに限られない。例えば、負極４１に放電リザーブ容量ＢＤＲが再び生じない範囲内（負極４１の放電容量ＢＤが正極３１の放電容量ＡＤ＝６．５Ａｈ以下の範囲内）で、負極４１の放電容量ＢＤを増加（回復）させてもよい。例えば、放電容量ＢＤを回復前のＢＤ＝３．５Ａｈから３．０Ａｈ増加させてＢＤ＝６．５Ａｈとしてもよい（放電リザーブ容量ＢＤＲは零のままである）。この例では、電池容量を出荷時初期の６．５Ａｈまで回復させることができる。また、放電容量ＢＤを回復前のＢＤ＝３．５Ａｈから２．０Ａｈ増加させて、出荷時初期の６．５Ａｈよりも少ないＢＤ＝５．５Ａｈまで回復させてもよい。 Further, in the embodiment, until the discharge reserve capacity BDR is generated again in the negative electrode 41, specifically, until the discharge reserve capacity BDR that was zero before the recovery is recovered to BDR = 2.5 Ah, which is the same as the initial value at the time of shipment. Although the case where the discharge capacity BD is increased by 5.5 Ah from BD = 3.5 Ah before recovery to BD = 9.0 Ah is shown, the present invention is not limited to this. For example, the discharge capacity BD of the negative electrode 41 is increased (recovered) within a range where the discharge reserve capacity BDR does not occur again in the negative electrode 41 (the discharge capacity BD of the negative electrode 41 is within the range of the discharge capacity AD = 6.5 Ah or less of the positive electrode 31). ). For example, the discharge capacity BD may be increased by 3.0 Ah from BD = 3.5 Ah before recovery to BD = 6.5 Ah (the discharge reserve capacity BDR remains zero). In this example, the battery capacity can be recovered to 6.5 Ah at the time of shipment. Further, the discharge capacity BD may be increased by 2.0 Ah from BD = 3.5 Ah before recovery to recover BD = 5.5 Ah, which is smaller than 6.5 Ah at the time of shipment.

また、実施形態では、劣化により負極４１の放電容量ＢＤが減って放電リザーブ容量ＢＤＲが無くなり、更には負極規制の状態となった電池１０を対象にして、負極４１の放電容量ＢＤを増加（回復）させたが、これに限られない。例えば、出荷時初期よりは負極４１の放電容量ＢＤが減ったものの、放電リザーブ容量ＢＤＲがまだ残っている電池を対象にして、負極４１の放電容量ＢＤを増加（回復）させてもよい。 In the embodiment, the discharge capacity BD of the negative electrode 41 is reduced due to the deterioration, the discharge reserve capacity BDR is eliminated, and the discharge capacity BD of the negative electrode 41 is increased (recovered) for the battery 10 in the negative electrode regulation state. ), But is not limited to this. For example, the discharge capacity BD of the negative electrode 41 may be increased (recovered) for a battery in which the discharge capacity BD of the negative electrode 41 has decreased from the initial shipping time but the discharge reserve capacity BDR still remains.

また、実施形態では、安全弁装置８０の開弁を強制開弁装置１５０を用いて強制的に行う場合を例示したが、これに限られない。例えば、充電（過充電）に伴って電池内圧が開弁圧に達することにより、安全弁装置８０を自然に開弁させてもよい。
また、実施形態では、１つの電池１０を対象として、負極４１の放電容量ＢＤを増加（回復）させたが、これに限られない。例えば、複数の電池１０を内蔵する電池パックについて、負極４１の放電容量ＢＤを増加（回復）させることもできる。 In the embodiment, the case where the safety valve device 80 is forcibly opened using the forced valve opening device 150 is illustrated, but the present invention is not limited thereto. For example, the safety valve device 80 may be naturally opened when the battery internal pressure reaches the valve opening pressure with charging (overcharge).
In the embodiment, the discharge capacity BD of the negative electrode 41 is increased (recovered) for one battery 10, but the present invention is not limited to this. For example, the discharge capacity BD of the negative electrode 41 can be increased (recovered) for a battery pack containing a plurality of batteries 10.

１０電池（ニッケル水素蓄電池）
２０電池ケース
３０電極体
３１正極
４１負極
８０安全弁装置
９０セル
１００負極放電容量回復装置
１１０充電装置
１２０充電回路
１３０充電制御装置（増加量設定手段、質量減少量設定手段、放電容量増加手段）
１４０質量測定装置
１５０強制開弁装置
１６０ガス流量計
ＡＥ正極容量
ＡＣ（正極の）充電容量
ＡＤ（正極の）放電容量
ＢＥ負極容量
ＢＣ（負極の）充電容量
ＢＣＲ充電リザーブ容量
ＢＤ（負極の）放電容量
ＢＤＲ放電リザーブ容量
ＧＡガス 10 Battery (Nickel metal hydride storage battery)
20 Battery Case 30 Electrode Body 31 Positive Electrode 41 Negative Electrode 80 Safety Valve Device 90 Cell 100 Negative Electrode Discharge Capacity Recovery Device 110 Charging Device 120 Charging Circuit 130 Charge Control Device (Increase Setting Unit, Mass Decreasing Amount Setting Device, Discharge Capacity Increasing Device)
140 Mass measuring device 150 Forced valve opening device 160 Gas flow meter AE Positive electrode capacity AC (positive electrode) charge capacity AD (positive electrode) discharge capacity BE Negative electrode capacity BC (negative electrode) charge capacity BCR Charge reserve capacity BD (negative electrode) discharge Capacity BDR Discharge reserve capacity GA Gas

Claims

For a nickel metal hydride storage battery comprising a positive electrode, a negative electrode, and a resettable safety valve device, a negative electrode discharge capacity recovery method for increasing the discharge capacity of the negative electrode,
An increase amount setting step for setting a target capacity increase amount for the discharge capacity of the negative electrode;
Based on the correlation between the mass decrease amount of the nickel metal hydride storage battery before and after the recovery and the capacity increase amount of the discharge capacity of the negative electrode, a mass decrease amount that sets a target mass decrease amount corresponding to the set target capacity increase amount Configuration steps;
Discharge that increases the discharge capacity of the negative electrode by charging the nickel-metal hydride storage battery to generate oxygen gas from the positive electrode and discharging at least a part of the oxygen gas to the outside of the battery through the opened safety valve device A capacity increasing step, and
The discharge capacity increasing step includes:
A negative electrode discharge capacity recovery method of charging the nickel-metal hydride storage battery until the mass reduction amount reaches the target mass reduction amount.

The negative electrode discharge capacity recovery method according to claim 1,
The discharge capacity increasing step includes:
A negative electrode discharge capacity recovery method which is performed while continuously measuring the mass of the nickel-metal hydride storage battery and continuously calculating the mass reduction amount.

The negative electrode discharge capacity recovery method according to claim 1 or 2,
The discharge capacity increasing step includes:
A negative electrode discharge capacity recovery method in which the safety valve device is forcibly opened to discharge at least a part of the generated oxygen gas.

The negative electrode discharge capacity recovery method according to any one of claims 1 to 3,
The discharge capacity increasing step includes:
A method for recovering a negative electrode discharge capacity, wherein the temperature of the nickel metal hydride storage battery at the start of charging is set to 30 ° C. or lower.

A negative electrode discharge capacity recovery method according to any one of claims 1 to 4,
The discharge capacity increasing step includes:
A method for recovering a negative electrode discharge capacity, which is performed with a charging current value of 6.0 C or less.

For a nickel metal hydride storage battery comprising a positive electrode, a negative electrode, and a return-type safety valve device, a negative electrode discharge capacity recovery device that increases the discharge capacity of the negative electrode,
A charging circuit for charging the nickel metal hydride storage battery;
A charge control device for controlling charging of the nickel metal hydride storage battery by the charging circuit;
A mass measuring device for measuring the mass of the nickel metal hydride storage battery,
The charge control device includes:
An increase amount setting means for setting a target capacity increase amount for the discharge capacity of the negative electrode;
Based on the correlation between the mass decrease amount of the nickel metal hydride storage battery before and after the recovery and the capacity increase amount of the discharge capacity of the negative electrode, a mass decrease amount that sets a target mass decrease amount corresponding to the set target capacity increase amount Setting means;
The nickel hydride storage battery is charged by the charging circuit to generate oxygen gas from the positive electrode, and at least a part of the oxygen gas is discharged outside the battery through the opened safety valve device, and the discharge capacity of the negative electrode Discharge capacity increasing means for increasing the discharge capacity, wherein the nickel hydride storage battery is charged until the mass reduction amount obtained by the measurement by the mass measuring device reaches the target mass reduction amount. Negative electrode discharge capacity recovery device.

The negative electrode discharge capacity recovery device according to claim 6,
The mass measuring device is capable of continuously measuring the mass of the nickel-metal hydride storage battery while charging the nickel-metal hydride storage battery,
The discharge capacity increasing means is a negative electrode discharge capacity recovery device that continuously calculates the mass reduction amount.

The negative electrode discharge capacity recovery device according to claim 6 or 7,
A negative electrode discharge capacity recovery device comprising a forced valve opening device for forcibly opening the safety valve device.

The negative electrode discharge capacity recovery device according to any one of claims 6 to 8,
The charging circuit is
A negative electrode discharge capacity recovery device for charging the nickel metal hydride storage battery with a charging current value of 6.0 C or less.