JP5084394B2 - How to calculate the remaining battery capacity - Google Patents

How to calculate the remaining battery capacity Download PDF

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JP5084394B2
JP5084394B2 JP2007210285A JP2007210285A JP5084394B2 JP 5084394 B2 JP5084394 B2 JP 5084394B2 JP 2007210285 A JP2007210285 A JP 2007210285A JP 2007210285 A JP2007210285 A JP 2007210285A JP 5084394 B2 JP5084394 B2 JP 5084394B2
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憲一 小林
真一 板垣
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Sanyo Electric Co Ltd
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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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本発明は、放電電流や放電電力を積算して電池の残容量を算出し、あるいは電池の電圧を検出して電池の残容量を算出する方法に関する。   The present invention relates to a method of calculating a remaining battery capacity by integrating discharge current and discharge power, or calculating a remaining battery capacity by detecting a battery voltage.

電池の残容量は、充電容量から放電容量を減算して算出できる。残容量を算出するには、満充電した電池を完全に放電するまでの容量、言い換えると完全に放電された電池を満充電するまでの容量である満充電容量（ＦＣＣ）を検出する必要がある。満充電された電池の満充電容量から放電された容量を減算して残容量を算出するからである。満充電容量は、電池が劣化するにしたがって減少する。電池が劣化するにしたがって、満充電容量を補正することで、劣化した電池の残容量を正確に算出できる。残容量を正確に算出するために、劣化する電池の満充電容量を補正する方法は開発されている。（特許文献１参照）   The remaining capacity of the battery can be calculated by subtracting the discharge capacity from the charge capacity. In order to calculate the remaining capacity, it is necessary to detect the capacity until the fully charged battery is fully discharged, in other words, the fully charged capacity (FCC) which is the capacity until the fully discharged battery is fully charged. . This is because the remaining capacity is calculated by subtracting the discharged capacity from the fully charged capacity of the fully charged battery. The full charge capacity decreases as the battery deteriorates. By correcting the full charge capacity as the battery deteriorates, the remaining capacity of the deteriorated battery can be accurately calculated. In order to accurately calculate the remaining capacity, a method for correcting the full charge capacity of a deteriorated battery has been developed. (See Patent Document 1)

この公報に記載される方法は、電池の充電容量の累積量から電池の劣化度を検出して、変化する満充電容量を補正する。この方法は、電池の劣化に対応する満充電容量を検出できる。ただ、電池の残容量は、満充電容量の正確な検出のみでは正確には検出できない。満充電容量から放電された容量、すなわち放電容量を減算して残容量を検出することから、残容量を正確に検出するには、放電容量も正確に検出する必要がある。   The method described in this publication detects the degree of battery deterioration from the accumulated amount of battery charge capacity, and corrects the changing full charge capacity. This method can detect the full charge capacity corresponding to the deterioration of the battery. However, the remaining capacity of the battery cannot be accurately detected only by accurately detecting the full charge capacity. Since the remaining capacity is detected by subtracting the discharged capacity from the full charge capacity, that is, the discharge capacity, it is necessary to accurately detect the discharge capacity in order to accurately detect the remaining capacity.

図１は、放電電流に対する放電効率を示す。この図は、放電電流が大きくなるにしたがって、放電効率が低下する状態を示すグラフである。放電効率は、電池の実質的な満充電容量を示すものであるから、この図は、放電電流が大きくなると、満充電容量が実質的に減少することを示している。この図において、たとえば、放電電流を大きくして、放電効率が５０％に低下する電池は、実質的に放電できる容量が半分に減少する。図１は、特定の設定電流で放電する電池の放電効率を１００％としている。放電効率を１００％とする電池は、満充電容量で放電できる。放電効率は放電電流で変化するので、特定の放電レートにおける放電効率を１００％として、放電効率を特定する。放電効率は、たとえば０．２Ｉｔの放電レートで１００％とされる。１Ｉｔの放電レートは、１時間で放電する電流であるから、満充電容量を１０００ｍＡｈとする電池を０．２Ｉｔの放電レートで放電する電流は、２００ｍＡとなる。２００ｍＡの電流で放電されて放電効率を１００％とする電池が、５倍の１０００ｍＡで放電されると、放電効率が小さくなって実質的に放電できる容量が８０％に小さくなる。放電電流で変化する放電効率で補正して、電池の残容量はより正確に算出できる。
特開２００２−２３６１５４号公報 FIG. 1 shows the discharge efficiency with respect to the discharge current. This figure is a graph showing a state in which the discharge efficiency decreases as the discharge current increases. Since the discharge efficiency indicates the substantial full charge capacity of the battery, this figure shows that the full charge capacity substantially decreases as the discharge current increases. In this figure, for example, in a battery whose discharge efficiency is reduced to 50% by increasing the discharge current, the dischargeable capacity is substantially reduced by half. In FIG. 1, the discharge efficiency of a battery that discharges at a specific set current is 100%. A battery having a discharge efficiency of 100% can be discharged with a full charge capacity. Since the discharge efficiency varies depending on the discharge current, the discharge efficiency is specified with the discharge efficiency at a specific discharge rate as 100%. The discharge efficiency is 100% at a discharge rate of 0.2 It, for example. Since the discharge rate of 1 It is a current that discharges in 1 hour, the current that discharges a battery with a full charge capacity of 1000 mAh at a discharge rate of 0.2 It is 200 mA. When a battery that is discharged at a current of 200 mA and has a discharge efficiency of 100% is discharged at 1000 mA, which is five times the discharge efficiency, the discharge efficiency decreases and the capacity that can be substantially discharged is reduced to 80%. The remaining capacity of the battery can be calculated more accurately by correcting with the discharge efficiency changing with the discharge current.
JP 2002-236154 A

電池の劣化度で満充電容量を補正し、さらに放電効率を考慮して補正することで残容量の演算精度は向上するが、この方法によっても、現実に放電させる電池の残容量は必ずしも正確に算出できない。とくに、電池が劣化するにしたがって残容量に誤差が発生する。   Correcting the full charge capacity based on the degree of deterioration of the battery and further taking into account the discharge efficiency improves the accuracy of calculating the remaining capacity, but even with this method, the remaining capacity of the battery that is actually discharged is not necessarily accurate. Cannot be calculated. In particular, an error occurs in the remaining capacity as the battery deteriorates.

本発明は、さらにこの欠点を解決することを目的に開発されたものである。本発明の重要な目的は、劣化した電池の残容量をより正確に算出できる電池の残容量の算出方法を提供することにある。   The present invention has been developed for the purpose of solving this drawback. An important object of the present invention is to provide a battery remaining capacity calculation method that can more accurately calculate the remaining capacity of a deteriorated battery.

本発明の電池の残容量の算出方法は、放電電流をパラメータとする放電効率で補正して電池の残容量を算出する。この算出方法は、電池が劣化するにしたがって、放電効率を補正して残容量を算出する。
In the battery remaining capacity calculation method according to the present invention, the remaining battery capacity is calculated by correcting with the discharge efficiency using the discharge current as a parameter. In this calculation method, the remaining capacity is calculated by correcting the discharge efficiency as the battery deteriorates .

本発明の電池の残容量の算出方法は、電池の放電電流又は放電電力である放電出力を積算すると共に、放電出力の積算値を電池の劣化で補正された放電効率で補正して電池の残容量を算出する。
The method of calculating the remaining capacity of the batteries of the present invention is to integrate the discharge output is the discharge current or discharge power of the battery, the integrated value of discharge power is corrected with the corrected discharge efficiency by the deterioration of the battery of the battery Calculate the remaining capacity.

本発明の電池の残容量の算出方法は、以下の式で特定される第１の劣化度で放電電流の補正係数を特定し、この補正係数と放電電流の積で算出される放電電流から放電効率を算出して残容量を演算する。
The method of calculating the remaining capacity of the batteries of the present invention, the first correction coefficient of the discharge current specified in deterioration degree, the discharge current is calculated by the product of the correction coefficient and the discharging current specified by the following formula Calculate the remaining capacity by calculating the discharge efficiency.

本発明の電池の残容量の算出方法は、電池の電圧を検出して設定電圧と比較し、電池電圧が設定電圧になると所定の残容量と判定する。さらに、この算出方法は、電池が劣化するにしたがって計算上の放電電流を大きくして補正する補正後の放電効率を使用して、以下の式で特定される第２の劣化度で設定電圧を補正して電池の残容量を算出する。
第２の劣化度＝［１−｛ＦＣＣ（補正後）×放電効率（補正後）｝／｛ＦＣＣ（初期）×放電効率（初期）｝］
ただし、この式においてＦＣＣ（Full charge capacity）は電池の満充電容量を示し、ＦＣＣ（補正後）は劣化した電池の満充電容量を、ＦＣＣ（初期）は劣化していない電池の満充電容量を示している。
また、放電効率（補正後）は電池の劣化で補正した放電効率を示し、放電効率（初期）は劣化していない電池の放電効率を示している。
The method of calculating the remaining capacity of the batteries of the present invention, compared to detect and set voltage the voltage of the battery, determining when the battery voltage reaches the set voltage to a predetermined remaining capacity. Further, this calculation method uses the corrected discharge efficiency that corrects the calculated discharge current as the battery deteriorates, and corrects the set voltage with the second degree of deterioration specified by the following equation. Compensate to calculate the remaining battery capacity.
Second degradation level = [1- {FCC (after correction) × Discharge efficiency (after correction)} / {FCC (initial) × Discharge efficiency (initial)}]
However, in this equation, FCC (Full charge capacity) indicates the full charge capacity of the battery, FCC (after correction) indicates the full charge capacity of the deteriorated battery, and FCC (initial) indicates the full charge capacity of the non-deteriorated battery. Show.
The discharge efficiency (after correction) indicates the discharge efficiency corrected by the deterioration of the battery, and the discharge efficiency (initial) indicates the discharge efficiency of the battery that has not deteriorated.

さらに、本発明の電池の残容量の算出方法は、第２の劣化度をパラメータとして設定電圧を補正する状態を２次以上のｎ次関数として記憶している。
Furthermore, the method for calculating the remaining capacity of the batteries of the present invention stores the state of correcting the setting voltage and the second degradation degree as a parameter as second or higher order n function.

本発明は劣化した電池の残容量をより正確に算出できる。それは、本発明が、電池が劣化するにしたがって、計算上の放電電流を大きくして放電効率も補正して残容量を算出するからである。劣化して満充電容量の減少した電池は、同じ電流で放電しても放電効率が変化する。それは、電池の放電効率が、満充電容量（Ａｈ）と放電電流（Ａ）の比率で特定される放電レートで変化するからである。満充電された電池を１時間で完全に放電する放電レートは１（Ｉｔ）で表される。たとえば、満充電容量を１０Ａｈとする電池が１Ａで放電されるときの放電レートは０．１Ｉｔとなる。たとえば、図１において、０．２Ｉｔの放電レートで放電されて放電効率を１００％とする電池が、その５倍の１Ｉｔの放電レートで放電されると、放電効率は８０％となって、実質的に放電できる満充電容量は２０％も小さくなる。劣化して満充電容量が小さくなった電池は、同じ放電電流で放電されても、放電効率が低下する特性であることから、本発明は、電池の劣化度で放電電流を補正する。すなわち、劣化して満充電容量が小さくなった電池は、計算上の放電電流を大きくして補正する。放電電流が大きく補正されると、図１の関係から放電効率が小さくなるように補正できる。現実の電池は、劣化すると放電効率が低下するので、本発明はより正確に残容量を算出できる。   The present invention can more accurately calculate the remaining capacity of a deteriorated battery. This is because the present invention calculates the remaining capacity by increasing the calculated discharge current and correcting the discharge efficiency as the battery deteriorates. A battery having a reduced full charge capacity due to deterioration changes its discharge efficiency even when discharged with the same current. This is because the discharge efficiency of the battery changes at the discharge rate specified by the ratio between the full charge capacity (Ah) and the discharge current (A). A discharge rate for completely discharging a fully charged battery in one hour is represented by 1 (It). For example, the discharge rate when a battery having a full charge capacity of 10 Ah is discharged at 1 A is 0.1 It. For example, in FIG. 1, when a battery that is discharged at a discharge rate of 0.2 It and has a discharge efficiency of 100% is discharged at a discharge rate of 1 It that is five times the discharge efficiency, the discharge efficiency becomes 80%, The full charge capacity that can be discharged is reduced by 20%. Since a battery having a reduced full charge capacity due to deterioration has a characteristic that the discharge efficiency is lowered even when discharged with the same discharge current, the present invention corrects the discharge current based on the degree of deterioration of the battery. In other words, the battery whose full charge capacity is reduced due to deterioration is corrected by increasing the calculated discharge current. When the discharge current is largely corrected, the discharge efficiency can be corrected so as to decrease from the relationship of FIG. When an actual battery deteriorates, the discharge efficiency decreases, so the present invention can calculate the remaining capacity more accurately.

とくに、本発明の算出方法は、電池の放電電流又は放電電力である放電出力を積算すると共に、放電出力の積算値を電池の劣化で補正された放電効率で補正して電池の残容量を算出する。この方法は、放電出力の積算値から正確に残容量を算出できる。それは、電池の劣化で放電電流を補正し、さらにこの補正された放電電流で放電効率を補正し、補正された放電効率で放電出力の積算値を補正するからである。
In particular, calculation out the method of the present invention is to integrate the discharge output is the discharge current or discharge power of the battery, the integrated value of discharge power is corrected with the corrected discharge efficiency by the deterioration of the battery remaining capacity of the battery calculate. In this method, the remaining capacity can be accurately calculated from the integrated value of the discharge output. This is because the discharge current is corrected by the deterioration of the battery, the discharge efficiency is corrected by the corrected discharge current, and the integrated value of the discharge output is corrected by the corrected discharge efficiency.

また、本発明の残容量の算出方法は、以下の式で特定される第１の劣化度で放電電流の補正係数を特定し、この補正係数と放電電流の積で算出される放電電流から放電効率を算出して残容量を演算する。
第１の劣化度＝［１−ＦＣＣ（補正後）／ＦＣＣ（初期）］
ただし、この式においてＦＣＣ（Full charge capacity）は電池の満充電容量を示し、ＦＣＣ（補正後）は劣化した電池の満充電容量を、ＦＣＣ（初期）は劣化していない電池の満充電容量を示す。
この方法は、第１の劣化度から劣化した電池の補正された放電電流を算出し、この放電電流から放電効率を算出するので、劣化した電池の放電効率を正確に算出して、残容量を高い精度で算出できる。
In addition, the remaining capacity calculation method of the present invention specifies a discharge current correction coefficient with the first degree of deterioration specified by the following equation, and discharges from the discharge current calculated by the product of the correction coefficient and the discharge current. Calculate the remaining capacity by calculating the efficiency.
First degree of degradation = [1-FCC (after correction) / FCC (initial)]
However, in this equation, FCC (Full charge capacity) indicates the full charge capacity of the battery, FCC (after correction) indicates the full charge capacity of the deteriorated battery, and FCC (initial) indicates the full charge capacity of the non-deteriorated battery. Show.
In this method, the corrected discharge current of the deteriorated battery is calculated from the first deterioration degree, and the discharge efficiency is calculated from this discharge current. Therefore, the discharge efficiency of the deteriorated battery is accurately calculated, and the remaining capacity is calculated. It can be calculated with high accuracy.

また、本発明の残容量の算出方法は、電池の電圧を検出して設定電圧と比較し、電池電圧が設定電圧になると所定の残容量と判定する残容量の算出方法であって、電池が劣化するにしたがって計算上の放電電流を大きくして補正する補正後の放電効率を使用して、以下の式で特定される第２の劣化度で設定電圧を補正する。
電池は、放電されて特定の残容量になると設定電圧まで低下する。ただ、放電される電池の残容量が設定値になる設定電圧は、電池の劣化度で変化する。図２は、電池が劣化するにしたがって、電圧特性が変化する状態を示している。この図の破線Ｘで示すように、設定電圧（ＬＶ）を固定した場合、電池が劣化するにつれて残容量が不正確になる。劣化する電池は電圧の低下が早く、設定電圧に低下する状態での残容量が新しい電池に比較して大きくなる。請求項４の方法は、以下の式で特定される電池の劣化度で設定電圧を補正して電池の残容量を算出する。第２の劣化度は、電池のＦＣＣ（満充電容量）と、電池の劣化で補正される放電効率から特定される。この第２劣化度から設定電圧を補正し、この設定電圧から電池の残容量を算出する。
第２の劣化度＝［１−｛ＦＣＣ（補正後）×放電効率（補正後）｝／｛ＦＣＣ（初期）×放電効率（初期）｝］
この方法は、設定電圧に低下する状態で、電池の残容量を正確に算出できる。それは、図２の鎖線Ｙで示すように、電池が劣化するにしたがって、所定の残容量となる設定電圧が低下するからである。
 The remaining capacity calculation method of the present invention is a method for calculating a remaining capacity in which a battery voltage is detected and compared with a set voltage, and a predetermined remaining capacity is determined when the battery voltage reaches the set voltage. Using the corrected discharge efficiency, which is corrected by increasing the calculated discharge current as it deteriorates, the set voltage is corrected with the second degree of deterioration specified by the following equation.
When the battery is discharged to a specific remaining capacity, it drops to the set voltage. However, the set voltage at which the remaining capacity of the discharged battery becomes a set value changes depending on the degree of deterioration of the battery. FIG. 2 shows a state in which the voltage characteristics change as the battery deteriorates. As indicated by the broken line X in this figure, when the set voltage (LV) is fixed, the remaining capacity becomes inaccurate as the battery deteriorates. A battery that deteriorates quickly drops in voltage, and the remaining capacity in a state where the voltage drops to a set voltage is larger than that of a new battery. The method of claim 4 calculates the remaining capacity of the battery by correcting the set voltage with the degree of deterioration of the battery specified by the following equation. The second degree of deterioration is specified from the FCC (full charge capacity) of the battery and the discharge efficiency corrected by the deterioration of the battery. The set voltage is corrected from the second deterioration degree, and the remaining battery capacity is calculated from the set voltage.
Second degradation level = [1- {FCC (after correction) × Discharge efficiency (after correction)} / {FCC (initial) × Discharge efficiency (initial)}]
With this method, the remaining capacity of the battery can be accurately calculated in a state where the set voltage is lowered. This is because, as indicated by a chain line Y in FIG. 2, as the battery deteriorates, the set voltage that becomes a predetermined remaining capacity decreases.

さらに、本発明の算出方法は、請求項４の構成に加えて、第２の劣化度をパラメータとして設定電圧を補正する状態を、２次以上のｎ次関数として記憶する。この方法は、電池の劣化で設定電圧をテーブルに記憶する方法に比較して、少ないメモリ容量に記憶して、設定電圧による電池の残容量を正確に算出できる。

Furthermore, it calculated out the method of the present invention, in addition to the configuration of claim 4, the state of correcting the setting voltage and the second degradation degree as a parameter is stored as n-th order function of second order or higher. This method can store the set voltage in a smaller memory capacity than the method of storing the set voltage in the table due to battery deterioration, and can accurately calculate the remaining battery capacity by the set voltage.

以下、本発明の実施例を図面に基づいて説明する。ただし、以下に示す実施例は、本発明の技術思想を具体化するための電池の残容量の算出方法を例示するものであって、本発明は電池の残容量の算出方法を以下の方法に特定しない。   Embodiments of the present invention will be described below with reference to the drawings. However, the examples shown below exemplify a method for calculating the remaining capacity of the battery for embodying the technical idea of the present invention, and the present invention uses the following method for calculating the remaining capacity of the battery. Not specified.

本発明の残容量の算出方法は、充電できる全ての電池、たとえばニッケル水素電池、ニッケルカドミウム電池、リチウムイオン二次電池の残容量の検出に使用できる。さらに、本発明の残容量の算出方法は、放電電流をパラメータとする放電効率で補正して電池の残容量を算出する。電池は、劣化するにしたがって、満充電した状態から完全に放電するまでの容量、すなわちＦＣＣ（満充電容量）が減少する。さらに、ＦＣＣの減少した電池は、同じ電流で放電しても放電レートは大きくなる。たとえば、初期の容量が１Ａｈの電池が劣化して、ＦＣＣが０．５Ａｈと半分になると、同じ電流で放電しても、ＦＣＣが半分となっているので、ＦＣＣに対する同じ放電電流を考慮すると、放電レートは２倍となる。放電レートが、放電電流／ＦＣＣ（Ａｈ）として、ＦＣＣとの比率で演算されるからである。電池の放電効率は、放電レートをパラメータとして変化し、放電レートが大きくなると放電効率は低下する。従来の方法は、残容量の算出に、放電電流をパラメータとする放電効率を考慮するが、電池のＦＣＣが減少して放電レートが大きくなることを考慮しない。このため、ＦＣＣ（満充電容量）が減少した結果、放電レートが大きくなると残容量の算出に誤差が発生する。本発明は、この弊害を解消するために、電池が劣化してＦＣＣが小さくなるにしたがって計算上の放電電流を大きくして放電効率を補正して残容量を算出する。   The remaining capacity calculation method of the present invention can be used to detect the remaining capacity of all rechargeable batteries, such as nickel metal hydride batteries, nickel cadmium batteries, and lithium ion secondary batteries. Furthermore, the remaining capacity calculation method of the present invention calculates the remaining capacity of the battery by correcting with the discharge efficiency using the discharge current as a parameter. As the battery deteriorates, the capacity from the fully charged state to the fully discharged state, that is, the FCC (full charge capacity) decreases. Furthermore, a battery with a reduced FCC has a higher discharge rate even when discharged with the same current. For example, if the battery with an initial capacity of 1 Ah deteriorates and the FCC is halved to 0.5 Ah, the FCC is halved even if discharged with the same current, so considering the same discharge current for the FCC, The discharge rate is doubled. This is because the discharge rate is calculated as a discharge current / FCC (Ah) in a ratio with the FCC. The discharge efficiency of the battery changes using the discharge rate as a parameter, and the discharge efficiency decreases as the discharge rate increases. The conventional method considers the discharge efficiency with the discharge current as a parameter in calculating the remaining capacity, but does not consider that the FCC of the battery decreases and the discharge rate increases. For this reason, if the discharge rate increases as a result of a decrease in FCC (full charge capacity), an error occurs in the calculation of the remaining capacity. In order to solve this problem, the present invention calculates the remaining capacity by correcting the discharge efficiency by increasing the calculated discharge current as the battery deteriorates and the FCC becomes smaller.

ここで、本発明の算出方法で電池の残容量が算出されるパック電池の一例を図３に示す。この図に示すパック電池は、充電できる電池１と、電池１の充放電の電流を検出する電流検出部２と、電池１の電圧を検出する電圧検出部３と、電池１の温度を検出する温度検出部４と、電流検出部２と電圧検出部３と温度検出部４の検出値から電池１の残容量を算出すると共に、電池１の充放電を監視、制御する制御・演算部５とを備える。電流検出部２、電圧検出部３、及び温度検出部４からの出力は、Ａ／Ｄコンバータ６でデジタル変換されて制御・演算部５に入力される。また、パック電池は、電池電圧、残容量、充放電電流値、電池温度等の各種の電池情報、各種指令の情報を、機器側に伝送する通信部８を備えている。さらに、制御・演算部５は、各種データを記憶するメモリ９を備えている。   Here, FIG. 3 shows an example of a battery pack in which the remaining capacity of the battery is calculated by the calculation method of the present invention. The battery pack shown in this figure is a battery 1 that can be charged, a current detector 2 that detects the charge / discharge current of the battery 1, a voltage detector 3 that detects the voltage of the battery 1, and a temperature of the battery 1. A temperature detection unit 4, a current detection unit 2, a voltage detection unit 3 and a control / calculation unit 5 for calculating the remaining capacity of the battery 1 from the detection values of the temperature detection unit 4 and monitoring and controlling the charge / discharge of the battery 1; Is provided. Outputs from the current detection unit 2, the voltage detection unit 3, and the temperature detection unit 4 are digitally converted by the A / D converter 6 and input to the control / calculation unit 5. Further, the battery pack includes a communication unit 8 that transmits various battery information such as battery voltage, remaining capacity, charge / discharge current value, battery temperature, and various command information to the device side. Further, the control / calculation unit 5 includes a memory 9 for storing various data.

制御・演算部５は、Ａ／Ｄコンバータ６から入力されるデータに基づいて、演算、比較、判定等を行う。すなわち、制御・演算部５は、電池１の充放電電流を積算して残容量を演算処理し、充電電流や電池電圧から電池１の満充電を検出し、また、異常電流、異常温度、異常電圧等を検出して充放電を制御する。制御・演算部５は、充放電スイッチ７をオンオフに制御して電池１の充放電を制御する。充放電スイッチ７は、たとえば、ＦＥＴ等からなるスイッチング素子で、制御・演算部５でオンオフ制御され、異常電流、異常温度、異常電圧の検出時にオフに切り換えられて電流を遮断する。さらに、制御・演算部５は、Ａ／Ｄコンバータ６でデジタル変換されたデータから電池１の残容量（Ａｈ）を算出している。本実施例では、制御・演算部５は、以下のように処理して残容量を算出する。   The control / calculation unit 5 performs calculations, comparisons, determinations, and the like based on data input from the A / D converter 6. That is, the control / calculation unit 5 calculates the remaining capacity by integrating the charging / discharging current of the battery 1, detects the full charge of the battery 1 from the charging current and the battery voltage, and detects abnormal current, abnormal temperature, abnormal Charge / discharge is controlled by detecting voltage or the like. The control / calculation unit 5 controls charging / discharging of the battery 1 by controlling the charging / discharging switch 7 to be turned on / off. The charging / discharging switch 7 is, for example, a switching element made of an FET or the like, and is controlled to be turned on / off by the control / arithmetic unit 5. Furthermore, the control / calculation unit 5 calculates the remaining capacity (Ah) of the battery 1 from the data digitally converted by the A / D converter 6. In the present embodiment, the control / calculation unit 5 performs the following processing to calculate the remaining capacity.

電池の残容量の算出は、放電電流又は放電電力である放電出力の積算値で演算される積算方式が利用される。そして、さらに、電池の残容量の演算は、放電している電池の電圧が設定電圧まで低下したとき、所定の残容量に補正する電圧方式とがある。   The remaining capacity of the battery is calculated using an integration method that is calculated by an integrated value of discharge output that is discharge current or discharge power. Further, the calculation of the remaining battery capacity includes a voltage method in which when the discharged battery voltage is reduced to a set voltage, the remaining battery capacity is corrected to a predetermined remaining capacity.

積算方式は、満充電された状態から放電された容量、すなわち放電電流又は放電電力である放電出力の積算値を減算して算出される。電池のＦＣＣは放電効率で変化するので、この方式は、放電効率で補正してより正確に残容量を算出できる。放電効率は放電電流をパラメータとして特定される。図４は放電電流に対する放電効率を示す。この図は放電電流が大きくなると放電効率が低下することを示している。さらに、放電効率は、放電電流のみでなく、電池の温度が設定温度から低下しても低下する。したがって、放電効率は、電池を、設定温度において定格電流で放電する状態を１００％として特定される。設定温度と定格電流は電池の種類により異なるが、電池をリチウムイオン二次電池とする場合、たとえば設定温度を２０℃、定格電流を２００ｍＡ（０．２Ｉｔ）とする。ただし、設定温度と定格電流は電池の種類により最適値に設定されるので、この値に特定されない。   The integration method is calculated by subtracting the integrated value of the discharge output, which is the discharge capacity or the discharge power, from the fully charged state. Since the FCC of the battery changes with the discharge efficiency, this method can correct the remaining capacity by correcting with the discharge efficiency. The discharge efficiency is specified using the discharge current as a parameter. FIG. 4 shows the discharge efficiency with respect to the discharge current. This figure shows that the discharge efficiency decreases as the discharge current increases. Furthermore, the discharge efficiency is reduced not only by the discharge current but also when the battery temperature is lowered from the set temperature. Therefore, the discharge efficiency is specified with the state where the battery is discharged at the rated current at the set temperature as 100%. Although the set temperature and the rated current vary depending on the type of the battery, when the battery is a lithium ion secondary battery, for example, the set temperature is 20 ° C. and the rated current is 200 mA (0.2 It). However, since the set temperature and the rated current are set to optimum values depending on the type of battery, they are not specified to these values.

積算方式は、以下の式で特定される第１の劣化度で放電電流の補正係数を特定し、この補正係数と放電電流の積で算出される補正された放電電流から放電効率を算出して残容量を演算する。
第１の劣化度＝［１−ＦＣＣ（補正後）／ＦＣＣ（初期）］
ただし、この式においてＦＣＣ（Full charge capacity）は電池の満充電容量を示し、ＦＣＣ（補正後）は劣化した電池の満充電容量を、ＦＣＣ（初期）は劣化していない電池の満充電容量を示す。 In the integration method, a correction coefficient of the discharge current is specified by the first degree of deterioration specified by the following formula, and the discharge efficiency is calculated from the corrected discharge current calculated by the product of the correction coefficient and the discharge current. Calculate the remaining capacity.
First degree of degradation = [1-FCC (after correction) / FCC (initial)]
However, in this equation, FCC (Full charge capacity) indicates the full charge capacity of the battery, FCC (after correction) indicates the full charge capacity of the deteriorated battery, and FCC (initial) indicates the full charge capacity of the non-deteriorated battery. Show.

たとえば、初期のＦＣＣ（上述の設定温度、定格電流を利用）が１Ａｈである電池が劣化して、ＦＣＣ（上述の設定温度、定格電流を利用）が０．８Ａｈに劣化した電池が、１０℃で満充電された状態から１００ｍＡで１時間放電されるとき、残容量は以下の方法で算出される。なお、０．８Ａｈに劣化した電池の容量（後述するＦＣＣ（補正後）に相当する）については、パック電池内のＣＰＵを含む制御?演算部を利用するのではなく、上述の設定温度、定格電流にて、放電させて、測定、検出、演算して求めている。また、０．８Ａｈに劣化した電池の容量（上述の設定温度、定格電流を利用）は、後述するように、バック電池内で、ＦＣＣ（補正後）（＝ＦＣＣ（学習後））としても演算される。上述の本出願人による特開２００２−２３６１５４号に開示されるように、以下のようにして、劣化した電池の容量として、その時点での電池の総容量（＝学習容量）を得ることができる。   For example, a battery whose initial FCC (using the above set temperature and rated current) is 1 Ah is deteriorated, and a battery whose FCC (using the above set temperature and rated current) is deteriorated to 0.8 Ah is 10 ° C. When the battery is discharged at 100 mA for 1 hour from the fully charged state, the remaining capacity is calculated by the following method. For the capacity of the battery deteriorated to 0.8 Ah (corresponding to FCC (after correction) described later), the control temperature calculation unit including the CPU in the battery pack is not used, but the above set temperature, rating It is obtained by discharging, measuring, detecting, and calculating with an electric current. Further, the capacity of the battery deteriorated to 0.8 Ah (using the above set temperature and rated current) is also calculated as FCC (after correction) (= FCC (after learning)) in the back battery, as will be described later. Is done. As disclosed in Japanese Patent Application Laid-Open No. 2002-236154 by the applicant, the total capacity (= learning capacity) of the battery at that time can be obtained as the capacity of the deteriorated battery as follows. .

その時点での電池の総容量（＝学習容量）としては、満充電した状態から完全または所定容量に放電されるまでの放電の積算容量（Ａｈ又はＷｈ）でも、電池を完全または所定容量に放電した状態から満充電されるまでの充電の積算容量（Ａｈ又はＷｈ）でもよい。 また、これ以外の方法でも、総容量が得られるのであれば、その時点での電池の総容量としても良い。さらには、電池の残容量補正方法を利用した総容量（＝学習容量）においては、電池の充電容量又は放電容量の累積量がそのときの電池の学習容量に達する毎に１サイクルとカウントし、１サイクルの充電又は放電につき、学習容量を特定のサイクル劣化容量として減少させ、あるいは、電池の保存温度と残容量をパラメータとして学習容量の減少率を保存劣化容量として特定し、保存時間が経過するにしたがって、電池の保存温度と残容量から特定された保存劣化容量で学習容量を減少させて、総容量を得ることができる。   As the total capacity of the battery (= learning capacity) at that time, even if the accumulated capacity (Ah or Wh) from the fully charged state until the battery is fully discharged or discharged to a predetermined capacity, the battery is fully discharged or discharged to a predetermined capacity. It may be an accumulated capacity (Ah or Wh) of charging until the battery is fully charged. If the total capacity can be obtained by other methods, the total capacity of the battery at that time may be used. Furthermore, in the total capacity (= learning capacity) using the remaining battery capacity correction method, every time the accumulated amount of the battery charging capacity or discharging capacity reaches the learning capacity of the battery, it is counted as one cycle. For one cycle of charging or discharging, the learning capacity is decreased as a specific cycle deterioration capacity, or the decrease rate of the learning capacity is specified as the storage deterioration capacity using the storage temperature and the remaining capacity of the battery as parameters, and the storage time elapses. Accordingly, the learning capacity is reduced by the storage deterioration capacity specified from the storage temperature and the remaining capacity of the battery, and the total capacity can be obtained.

（１）第１の劣化度が以下の式で演算される。
第１の劣化度＝［１−０．８Ａｈ／１Ａｈ］＝１−０．８＝０．２
（２）第１の劣化度から放電電流が補正される。図５のグラフに示す関数から、あるいはテーブルから第１の劣化度に対する補正係数を特定し、この補正係数を放電電流に掛け算して、放電電流を補正する。この図の関数やテーブルは、あらかじめ制御・演算部５の記憶回路であるメモリ９に記憶している。この図から第１の劣化度である０．２に対応した補正係数が得られる。
（３）図５から、第１の劣化度を０．２とする状態における補正係数が、たとえば１．８と特定されると、補正された放電電流は、放電電流と補正係数の積となるので、１００ｍＡ×１．８となって、１８０ｍＡに補正される。換言すると、図５は、初期の何倍の放電レートに相当するかを示している。
（４）図４から補正された放電電流に対する放電効率（補正後）が特定される。この図において、温度を１０℃として、放電電流を１８０ｍＡとする放電効率（補正後）は８５％と特定される。放電効率（補正後）は、温度、放電電流に依存することになる。図４においては、１０℃、２０℃しか開示されていないが、記憶される関数、テーブルには、各温度における放電電流に対する放電効率を記憶している。
（５）温度１０℃（実際の温度）、放電電流１００ｍＡ（実際の放電電流）のとき、ＦＣＣ０．８Ａｈ（上述の設定温度、定格電流を利用）に劣化した電池において、電池の実質的なＦＣＣ（上述の実際の温度、放電電流において、満充電した状態から完全に放電するまでの残容量）は、ＦＣＣと放電効率の積となるので、０．８Ａｈ×０．８５となって、０．６８Ａｈとなる。一般式は以下の通りである。
電池の実質的なＦＣＣ（実際の温度、実際の放電電流を利用）＝ＦＣＣ（補正後）×放電効率（補正後）
ただし、この式において、ＦＣＣ（補正後）は劣化した電池の満充電容量（設定温度、定格電流を利用）を示している。
（６）電池が、１００ｍＡで１時間放電されたことから、放電容量は１００ｍＡ×１時間、すなわち０．１Ａｈとなる。
（７）電池の実質的な容量（上述の実際の温度、放電電流において、満充電した状態から完全に放電するまでの残容量）は、（５）から０．６８Ａｈであるから、０．６８Ａｈ−０．１Ａｈとなって、０．５８Ａｈとなる。 (1) The first deterioration degree is calculated by the following equation.
First degree of degradation = [1-0.8 Ah / 1 Ah] = 1-0.8 = 0.2
(2) The discharge current is corrected from the first degree of deterioration. A correction coefficient for the first deterioration degree is specified from the function shown in the graph of FIG. 5 or from the table, and the discharge current is corrected by multiplying the correction coefficient by the discharge current. The functions and tables in this figure are stored in advance in a memory 9 that is a storage circuit of the control / arithmetic unit 5. From this figure, a correction coefficient corresponding to 0.2 which is the first deterioration degree is obtained.
(3) From FIG. 5, when the correction coefficient in the state where the first degree of deterioration is 0.2 is specified as 1.8, for example, the corrected discharge current is the product of the discharge current and the correction coefficient. Therefore, 100 mA × 1.8, which is corrected to 180 mA. In other words, FIG. 5 shows how many times the initial discharge rate corresponds.
(4) The discharge efficiency (after correction) with respect to the corrected discharge current is specified from FIG. In this figure, the discharge efficiency (after correction) at a temperature of 10 ° C. and a discharge current of 180 mA is specified as 85%. Discharge efficiency (after correction) depends on temperature and discharge current. Although only 10 ° C. and 20 ° C. are disclosed in FIG. 4, the stored functions and tables store the discharge efficiency with respect to the discharge current at each temperature.
(5) When the temperature is 10 ° C. (actual temperature) and the discharge current is 100 mA (actual discharge current), the actual FCC of the battery has deteriorated to FCC 0.8 Ah (using the above set temperature and rated current). (Remaining capacity from full charge to complete discharge at the above-mentioned actual temperature and discharge current) is the product of FCC and discharge efficiency, and thus becomes 0.8 Ah × 0.85. 68Ah. The general formula is as follows.
The actual FCC of the battery (actual temperature, actual discharge current is used) = FCC (after correction) x discharge efficiency (after correction)
However, in this equation, FCC (after correction) indicates the full charge capacity (using set temperature and rated current) of the deteriorated battery.
(6) Since the battery was discharged at 100 mA for 1 hour, the discharge capacity was 100 mA × 1 hour, that is, 0.1 Ah.
(7) Since the substantial capacity of the battery (remaining capacity from the fully charged state to the complete discharge at the above-described actual temperature and discharge current) is 0.68 Ah from (5), 0.68 Ah. It becomes -0.1Ah and becomes 0.58Ah.

そして、上述のように得られる残容量は、パック電池のマイコン内、制御・演算部５において、以下の設定温度、定格電流時に換算した残容量であるＲＣの式にて、逐次、演算されることになる。また、ＲＳＯＣは、以下の式で求めることができる。
ＲＣ＝ＲＣ−∫ＩΔｔ／放電効率（補正後）
ＲＳＯＣ＝ＲＣ／ＦＣＣ（補正後）
ただし、ＲＣは、設定温度、定格電流時に換算した残容量（＝放電効率を加味した見せかけの容量）であり、∫ＩΔｔは、電流積算値であり、また、ＲＳＯＣは、残容量率（％）である。そして、放電時の実際の温度、放電電流値に対応した実質的な残容量は、ＲＣ×放電効率（補正後）より、得ることができる。なお、上式における放電効率（補正後）、ＦＣＣ（補正後）については、補正が行われていない初期状態においては、劣化を加味していない初期の放電効率、ＦＣＣを利用する。 Then, the remaining capacity obtained as described above is sequentially calculated in the microcomputer of the battery pack, in the control / calculation unit 5 by the following RC formula which is the remaining capacity converted at the set temperature and rated current. It will be. RSOC can be obtained by the following equation.
RC = RC−∫IΔt / Discharge efficiency (after correction)
RSOC = RC / FCC (after correction)
However, RC is the remaining capacity converted at the set temperature and rated current (= apparent capacity taking discharge efficiency into account), ∫IΔt is the current integrated value, and RSOC is the remaining capacity ratio (%). It is. A substantial remaining capacity corresponding to the actual temperature and discharge current value at the time of discharge can be obtained from RC × discharge efficiency (after correction). In addition, regarding the discharge efficiency (after correction) and FCC (after correction) in the above formula, in the initial state where correction is not performed, the initial discharge efficiency and FCC not taking into account deterioration are used.

以上の積算方式は、電池のＦＣＣを電流と時間の積、すなわちＡｈで表示して、放電容量も放電電流と放電時間の積、すなわちＡｈで表示する。ただし、電池のＦＣＣは電流と電圧と時間の積、すなわちＷｈで表示することもできる。この場合、放電容量は放電電力の積算値、すなわち放電電流と放電電圧と時間の積で演算する。   In the above integration method, the FCC of the battery is displayed as a product of current and time, that is, Ah, and the discharge capacity is also displayed as the product of discharge current and discharge time, that is, Ah. However, the FCC of the battery can also be displayed as a product of current, voltage and time, that is, Wh. In this case, the discharge capacity is calculated by the integrated value of the discharge power, that is, the product of the discharge current, the discharge voltage, and the time.

さらに、以上の方法は、満充電された電池を放電して、残容量を算出する方法を例示するが、所定の残容量にある電池を放電して残容量を算出する場合も、前述したように、放電電流を第１の劣化度で補正して放電効率を特定し、特定された放電効率で電池の残容量を補正して、正確に残容量を算出することができる。   Further, the above method exemplifies a method of calculating a remaining capacity by discharging a fully charged battery. However, when the remaining capacity is calculated by discharging a battery at a predetermined remaining capacity, as described above. In addition, it is possible to accurately calculate the remaining capacity by correcting the discharge current with the first deterioration degree to identify the discharge efficiency and correcting the remaining capacity of the battery with the identified discharge efficiency.

電圧方式は、放電している電池の電圧が設定電圧になったことを検出して、残容量を特定する。図２は、放電容量に対する電圧特性を示すグラフである。この図に示すように、電池は満充電した状態から放電するにしたがって電圧が低下し、所定の残容量になると設定電圧まで低下する。電池の残容量がほぼ一定となる特定電圧を設定電圧とする。このことから、電池の電圧を検出して設定電圧と比較し、電池電圧が設定電圧になると所定の残容量と判定できる。この電圧方式で電池の残容量を算出する回路は、たとえば、電池の残容量が所定容量（たとえば３％、４％、５％、または８％の値が採用できる。）に低下する状態での電池電圧を設定電圧として記憶している。設定電圧は、所定容量で変化する。たとえば、電圧が３Ｖまで低下する状態で、残容量が８％となるリチウムイオン二次電池は、電池の電圧を検出して設定電圧の３Ｖに比較し、電池電圧が３Ｖになると所定容量の８％と特定できる。つまり、放電電流又は放電電力である放電出力の積算値で演算される積算方式から算出される残容量を、所定容量の８％と補正する。その後、同様に積算方式から残容量を積算する。このような残容量の算出方法については、本出願人による特開平１０−２１３６３８号に開示がある。   In the voltage method, the remaining capacity is specified by detecting that the voltage of the discharged battery has reached the set voltage. FIG. 2 is a graph showing voltage characteristics with respect to discharge capacity. As shown in this figure, the voltage of the battery decreases as it is discharged from the fully charged state, and decreases to the set voltage when it reaches a predetermined remaining capacity. A specific voltage at which the remaining capacity of the battery is almost constant is set as the set voltage. From this, the voltage of the battery is detected and compared with the set voltage, and when the battery voltage becomes the set voltage, it can be determined as a predetermined remaining capacity. The circuit for calculating the remaining capacity of the battery by this voltage method is, for example, in a state where the remaining capacity of the battery is reduced to a predetermined capacity (for example, a value of 3%, 4%, 5%, or 8% can be adopted). The battery voltage is stored as a set voltage. The set voltage changes with a predetermined capacity. For example, in a state where the voltage drops to 3V, a lithium ion secondary battery with a remaining capacity of 8% detects the battery voltage and compares it with the set voltage of 3V. %. That is, the remaining capacity calculated from the integration method calculated by the integrated value of the discharge output that is the discharge current or the discharge power is corrected to 8% of the predetermined capacity. Thereafter, the remaining capacity is similarly accumulated from the accumulation method. Such a remaining capacity calculation method is disclosed in Japanese Patent Laid-Open No. 10-213638 by the present applicant.

ただ、図２に示すように、電池が劣化するにしたがって、３Ｖの設定電圧は変化する。図２は、電池が劣化するにしたがって、電圧特性が変化する状態を示している。この図において、曲線Ａ〜Ｄは、劣化度が異なる電池の電圧特性を示している。曲線Ａは未使用の電池の特性を、曲線ＢないしＤは、充放電のサイクルを、それぞれ２００回、３００回、４００回繰り返した電池の特性を示している。すなわち、曲線Ａで示す電池から曲線Ｄで示す電池に向かって、充放電のサイクルが多くなって電池が劣化する状態を示している。この図に示すように、電池電圧が破線Ｘで示す設定電圧（ＬＶ）に低下しても、劣化度によって残容量が変化する。この図において、電池電圧が設定電圧（ＬＶ）に低下した状態における残容量をハッチングで示し、所定容量をクロスハッチングで示している。このように、劣化する電池は、電圧の低下が早く、設定電圧に低下する状態での残容量が新しい電池に比較して大きくなる。いいかえると、電池は、劣化するにしたがって、同じ所定容量とする設定電圧が、図の一点鎖線Ｙで示すように、次第に低下する。電圧方式で残容量を算出する方法は、電池が劣化するにしたがって計算上の放電電流を大きくして補正する補正後の放電効率を使用して、以下の式で特定される第２の劣化度で設定電圧を補正して電池の残容量を算出する。
第２の劣化度＝［１−｛ＦＣＣ（補正後）×放電効率（補正後）｝／｛ＦＣＣ（初期）×放電効率（初期）｝］ However, as shown in FIG. 2, the set voltage of 3V changes as the battery deteriorates. FIG. 2 shows a state in which the voltage characteristics change as the battery deteriorates. In this figure, curves A to D show voltage characteristics of batteries having different degrees of deterioration. Curve A shows the characteristics of an unused battery, and curves B to D show the characteristics of a battery obtained by repeating charging and discharging cycles 200 times, 300 times, and 400 times, respectively. That is, a state in which the battery deteriorates due to an increase in charge / discharge cycles from the battery indicated by the curve A toward the battery indicated by the curve D is shown. As shown in this figure, even when the battery voltage drops to the set voltage (LV) indicated by the broken line X, the remaining capacity changes depending on the degree of deterioration. In this figure, the remaining capacity in a state where the battery voltage is lowered to the set voltage (LV) is indicated by hatching, and the predetermined capacity is indicated by cross hatching. Thus, the battery that deteriorates has a fast voltage drop, and the remaining capacity in a state where the voltage drops to the set voltage is larger than that of a new battery. In other words, as the battery deteriorates, the set voltage having the same predetermined capacity gradually decreases as indicated by the alternate long and short dash line Y in the figure. The method of calculating the remaining capacity by the voltage method uses the corrected discharge efficiency that increases and corrects the calculated discharge current as the battery deteriorates, and uses the second degree of deterioration specified by the following equation. To correct the set voltage and calculate the remaining battery capacity.
Second degradation level = [1- {FCC (after correction) × Discharge efficiency (after correction)} / {FCC (initial) × Discharge efficiency (initial)}]

第２の劣化度から設定電圧を特定するために、第２の劣化度をパラメータとして、設定電圧を補正する状態を２次以上のｎ次関数として制御・演算部５のメモリ９に記憶している。図６は、第２の劣化度をパラメータとして、設定電圧を補正する補正係数を示すグラフである。このグラフに示す曲線を関数として記憶している。設定電圧と補正係数の積が、劣化して補正した電池の設定電圧となる。ただし、メモリ９に記憶される関数は、設定電圧との差電圧を関数として記憶し、あるいは、直接に設定電圧を示す関数として記憶することもできる。   In order to specify the set voltage from the second degree of deterioration, the state of correcting the set voltage is stored in the memory 9 of the control / arithmetic unit 5 as a second-order or higher-order n-order function using the second degree of deterioration as a parameter. Yes. FIG. 6 is a graph showing a correction coefficient for correcting the set voltage using the second deterioration degree as a parameter. The curve shown in this graph is stored as a function. The product of the set voltage and the correction coefficient becomes the set voltage of the battery that has been corrected due to deterioration. However, the function stored in the memory 9 can be stored as a function of a difference voltage from the set voltage or directly as a function indicating the set voltage.

電圧方式は、以下の条件で放電される電池の残容量が所定容量（たとえば８％の残容量）になったことを、以下の方法で算出する。
たとえば、前述した積算方式と同様に、初期にＦＣＣ（上述の設定温度、定格電流を利用）が１Ａｈ、所定容量が８％となる電圧を３Ｖとする電池が劣化して、ＦＣＣ（上述の設定温度、定格電流を利用）が上述のように０．８Ａｈに低下し、さらにこの電池を１０℃において１００ｍＡで放電するとき、劣化した電池の補正された設定電圧を以下の方法で算出する。
この方法は、最初に第２の劣化度を算出し、算出された第２の劣化度で設定電圧を補正する。第２の劣化度は以下の方法で算出される。
（１）劣化した電池の放電効率（補正後）を算出する。放電効率（補正後）は、前述した方法と同様に算出して、０．８５と特定される。
（２）放電効率（初期）を算出する。この放電効率は、図４から特定される。すなわち、１０℃における放電電流を１００ｍＡとするので、放電効率は０．９となる。
（３）第２の劣化度は以下のように演算される。
第２の劣化度＝［１−（０．８×０．８５）／（１×０．９）］
＝１−０．６８／０．９
＝０．２４ The voltage method calculates that the remaining capacity of the battery discharged under the following conditions has reached a predetermined capacity (for example, 8% remaining capacity) by the following method.
For example, in the same manner as the integration method described above, a battery having an FCC (using the above-described set temperature and rated current) of 1 Ah and a voltage with a predetermined capacity of 8% at the initial stage deteriorates, and the FCC (the above-described setting As described above, when the battery is discharged at 100 mA at 10 ° C., the corrected set voltage of the deteriorated battery is calculated by the following method.
In this method, the second deterioration degree is calculated first, and the set voltage is corrected with the calculated second deterioration degree. The second deterioration degree is calculated by the following method.
(1) The discharge efficiency (after correction) of the deteriorated battery is calculated. The discharge efficiency (after correction) is calculated in the same manner as described above and specified as 0.85.
(2) The discharge efficiency (initial) is calculated. This discharge efficiency is specified from FIG. That is, since the discharge current at 10 ° C. is 100 mA, the discharge efficiency is 0.9.
(3) The second deterioration degree is calculated as follows.
Second degree of degradation = [1− (0.8 × 0.85) / (1 × 0.9)]
= 1-0.68 / 0.9
= 0.24

第２の劣化度が算出されると、この値から記憶する関数で補正係数を算出する。第２の劣化度に対する補正係数を図６に示している。記憶される関数から、第２の劣化度を０．２４とする電池の補正係数は、０．９７と特定される。初期の電池の設定電圧（＝ＬＶ（初期値））が３Ｖであるから、劣化した電池の補正された設定電圧（＝ＬＶ（補正後））は、３Ｖ×０．９７となって、２．９Ｖとなる。したがって、前述の条件で放電されるとき、劣化した電池の残容量は、電圧が設定電圧の２．９Ｖまで電圧が低下するときに、所定容量の８％であると特定できる。
一般式で表現すると以下のようになる。
ＬＶ（補正後）＝ＬＶ（初期値）×補正係数（ＬＶ）
また、初期の電池の設定電圧（＝ＬＶ（初期値））を、温度、放電電流値に、依存させることも可能である。 When the second deterioration degree is calculated, a correction coefficient is calculated using a function stored from this value. FIG. 6 shows correction coefficients for the second degree of deterioration. From the stored function, the correction coefficient of the battery having the second deterioration degree of 0.24 is specified as 0.97. Since the initial set voltage (= LV (initial value)) of the battery is 3V, the corrected set voltage (= LV (after correction)) of the deteriorated battery is 3V × 0.97. 9V. Therefore, when discharged under the aforementioned conditions, the remaining capacity of the deteriorated battery can be specified to be 8% of the predetermined capacity when the voltage drops to 2.9 V of the set voltage.
Expressed as a general formula:
LV (after correction) = LV (initial value) × correction coefficient (LV)
It is also possible to make the initial setting voltage (= LV (initial value)) of the battery depend on the temperature and the discharge current value.

補正された設定電圧より、以下の式で、現在のＦＣＣ（＝ＦＣＣ（学習前））から、次のＦＣＣ（＝ＦＣＣ（学習後））を得ることができる。
ＦＣＣ（学習後）＝｛∫ＩΔｔ／０．９２｝／放電効率（補正後）
そして、このＦＣＣを、次回からのＦＣＣとして利用する。
ここで、所定容量の８％まで、電流を積算しているので、０．９２（＝１．００−０．０８）にて割り算すると、残容量０％までの電流積算に相当する容量を得ることができる。
ここで、∫ＩΔｔは、満充電から設定電圧までの電流積算値であって、∫ＩΔｔ／０．９２は、実際の温度、放電電流における上述の総容量（＝学習容量）に相当し、ＦＣＣ（学習後）は、上述の劣化した電池の容量（＝ＦＣＣ（補正後））に相当する。 From the corrected set voltage, the next FCC (= FCC (after learning)) can be obtained from the current FCC (= FCC (before learning)) by the following equation.
FCC (after learning) = {∫IΔt / 0.92} / discharge efficiency (after correction)
This FCC is used as the next FCC.
Here, since the current is integrated up to 8% of the predetermined capacity, when dividing by 0.92 (= 1.00−0.08), a capacity corresponding to the current integration up to the remaining capacity of 0% is obtained. be able to.
Here, ∫IΔt is a current integrated value from full charge to set voltage, and ∫IΔt / 0.92 corresponds to the above-mentioned total capacity (= learning capacity) at actual temperature and discharge current, and FCC (After learning) corresponds to the above-described deteriorated battery capacity (= FCC (after correction)).

上述の式においては、次回のＦＣＣへの変化量が大きいときがあるので、次の式で、ＦＣＣを得ることもできる。
ＦＣＣ（学習後）＝［ＦＣＣ（学習前）−｛∫ＩΔｔ／０．９２｝／放電効率（補正後）］×（０．３〜０．７）＋ＦＣＣ（学習前）
この式では、４〜５回程度の充放電サイクルをまわすことで最適なＦＣＣ値に収束するが、メモリ容量が大きい場合は、放電カーブを記憶しておき、一回の放電サイクルで記憶していた放電カーブを用いて４〜５回程度の反復計算を行うことで、１回のサイクルで収束させることもできる。 In the above formula, since the amount of change to the next FCC may be large, the FCC can also be obtained by the following formula.
FCC (after learning) = [FCC (before learning) − {∫IΔt / 0.92} / discharge efficiency (after correction)] × (0.3 to 0.7) + FCC (before learning)
In this equation, the optimum FCC value is converged by turning about 4 to 5 charge / discharge cycles. However, when the memory capacity is large, the discharge curve is stored and stored in one discharge cycle. It is also possible to converge in one cycle by performing iterative calculation about 4 to 5 times using the discharge curve.

本発明は電池が劣化しても残容量を正確に算出できることから、電池を繰り返し放電して劣化する状態においても、残容量を正確に表示して便利に使用できる。   Since the present invention can accurately calculate the remaining capacity even when the battery is deteriorated, the remaining capacity can be accurately displayed and used conveniently even when the battery is repeatedly discharged and deteriorated.

放電電流に対する放電効率を示すグラフである。It is a graph which shows the discharge efficiency with respect to a discharge current. 電池が劣化するにしたがって電圧特性が変化する状態を示すグラフである。It is a graph which shows the state from which a voltage characteristic changes as a battery deteriorates. 本発明の一実施例にかかる電池の残容量の算出方法に使用するパック電池のブロック図である。It is a block diagram of the pack battery used for the calculation method of the remaining capacity of the battery concerning one Example of this invention. 電池温度に対する放電電流と放電効率の関係を示すグラフである。It is a graph which shows the relationship between the discharge current with respect to battery temperature, and discharge efficiency. 第１の劣化度と放電電流の補正係数の関係を示すグラフである。It is a graph which shows the relationship between the 1st deterioration degree and the correction coefficient of discharge current. 第２の劣化度と設定電圧の補正係数の関係を示すグラフである。It is a graph which shows the relationship between the 2nd degradation degree and the correction coefficient of a setting voltage.

符号の説明Explanation of symbols

１…電池
２…電流検出部
３…電圧検出部
４…温度検出部
５…制御・演算部
６…Ａ／Ｄコンバータ
７…充放電スイッチ
８…通信部
９…メモリ DESCRIPTION OF SYMBOLS 1 ... Battery 2 ... Current detection part 3 ... Voltage detection part 4 ... Temperature detection part 5 ... Control and calculation part 6 ... A / D converter 7 ... Charge / discharge switch 8 ... Communication part 9 ... Memory

Claims (3)

放電電流をパラメータとする放電効率で補正して電池の残容量を算出する方法であって、
電池が劣化するにしたがって放電効率を補正して残容量を算出し、
電池の放電電流又は放電電力である放電出力を積算すると共に、放電出力の積算値を電池の劣化で補正された放電効率で補正して電池の残容量を算出し、
以下の式で特定される第１の劣化度で放電電流の補正係数を特定し、この補正係数と放電電流の積で算出される放電電流から放電効率を補正して残容量を演算することを特徴とする電池の残容量の算出方法。
第１の劣化度＝［１−ＦＣＣ（補正後）／ＦＣＣ（初期）］
ただし、この式においてＦＣＣ（Full charge capacity）は電池の満充電容量を示し、ＦＣＣ（補正後）は劣化した電池の満充電容量を、ＦＣＣ（初期）は劣化していない電池の満充電容量を示す。 A method of calculating the remaining capacity of a battery by correcting the discharge efficiency with the discharge current as a parameter,
As the battery deteriorates, the remaining capacity is calculated by correcting the discharge efficiency ,
Accumulating the discharge output which is the discharge current or discharge power of the battery, calculating the remaining capacity of the battery by correcting the integrated value of the discharge output with the discharge efficiency corrected by the deterioration of the battery ,
The discharge current correction coefficient is specified by the first deterioration level specified by the following equation, and the remaining capacity is calculated by correcting the discharge efficiency from the discharge current calculated by the product of the correction coefficient and the discharge current. A method for calculating a remaining battery capacity.
First degree of degradation = [1-FCC (after correction) / FCC (initial)]
However, in this equation, FCC (Full charge capacity) indicates the full charge capacity of the battery, FCC (after correction) indicates the full charge capacity of the deteriorated battery, and FCC (initial) indicates the full charge capacity of the non-deteriorated battery. Show. 電池の電圧を検出して設定電圧と比較し、電池電圧が設定電圧になると所定の残容量と判定する残容量の算出方法であって、電池が劣化するにしたがって計算上の放電電流を大きくして補正する補正後の放電効率を使用して、以下の式で特定される第２の劣化度で設定電圧を補正して電池の残容量を算出する請求項１に記載される電池の残容量の算出方法。
第２の劣化度＝［１−｛ＦＣＣ（補正後）×放電効率（補正後）｝／｛ＦＣＣ（初期）×放電効率（初期）｝］
ただし、この式においてＦＣＣ（Full charge capacity）は電池の満充電容量を示し、ＦＣＣ（補正後）は劣化した電池の満充電容量を、ＦＣＣ（初期）は劣化していない電池）は劣化していない電池の放電効率を示す This is a method for calculating the remaining capacity that detects the battery voltage and compares it with the set voltage, and determines that the battery has a predetermined remaining capacity when the battery voltage reaches the set voltage, and increases the calculated discharge current as the battery deteriorates. The remaining capacity of the battery according to claim 1, wherein the remaining capacity of the battery is calculated by correcting the set voltage with the second degree of deterioration specified by the following equation using the corrected discharge efficiency corrected by: Calculation method.
Second degradation level = [1- {FCC (after correction) × Discharge efficiency (after correction)} / {FCC (initial) × Discharge efficiency (initial)}]
In this formula, FCC (Full charge capacity) indicates the full charge capacity of the battery, FCC (after correction) indicates the full charge capacity of the deteriorated battery, and FCC (initial) does not deteriorate. No battery discharge efficiency 第２の劣化度をパラメータとして設定電圧を補正する状態を２次以上のｎ次関数として記憶する請求項２に記載される電池の残容量の算出方法。
The method for calculating the remaining capacity of the battery according to claim 2 , wherein a state in which the set voltage is corrected using the second deterioration level as a parameter is stored as a second-order or higher-order n-order function.
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