JP2001006757A - Residual capacity detecting device for lithium ion battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a residual capacity detecting device for a lithium ion battery for detecting residual capacity of the battery by calculating reference battery by detecting a surface temperature, terminal voltage and load current of the lithium ion battery and comparing this calculated reference voltage to a present terminal voltage. SOLUTION: This residual capacity detecting device 1 for lithium ion battery is constituted of a lithium ion battery 2, a surface temperature detecting means 4, a load current detecting means 5, a terminal voltage detecting means 6 and a residual capacity calculating means 7 and can be made the residual capacity detecting device 1 for lithium ion battery for accurately detecting the residual capacity of the battery.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for detecting a remaining capacity of a secondary battery, and more particularly, to calculating a reference voltage based on a terminal voltage, a load current, and a surface temperature of a lithium ion battery, and The present invention relates to a remaining capacity detection device for a lithium ion battery that corrects a reference voltage according to a transient state and calculates the remaining capacity of the lithium ion battery based on the corrected reference voltage and the detected terminal voltage.

[0002]

2. Description of the Related Art A conventional battery remaining capacity detecting device detects a battery voltage differently when there is a load connected to the battery and when there is no load as disclosed in Japanese Patent Application Laid-Open No. Hei 7-235334. However, the switch is set so that the detection voltage for displaying the remaining amount matches when there is a load and when there is no load, and the correction is performed. The remaining amount of the battery is determined based on whether the detection voltage is higher or lower than a predetermined value. Apparatuses for detecting the remaining capacity are known.

[0003] Further, the conventional battery remaining capacity detection method disclosed in Japanese Patent Publication No. 1-39069 detects a battery discharge current and a battery terminal voltage during large current discharge.
The electromotive force and short-circuit current of the battery are calculated based on the detected value, and the calculated values are substituted into a function representing the correlation between the maximum output and the remaining battery capacity obtained experimentally in advance to calculate the current remaining battery capacity. It is known that the remaining battery capacity is used to prevent the battery from running out and to predict the time of replacement.

FIG. 7 is a characteristic diagram showing a correlation between a battery discharge current and a terminal voltage for calculating a conventional battery remaining capacity disclosed in Japanese Patent Publication No. 1-39069. 7, the horizontal axis represents the discharge current Ib, the vertical axis represents the battery terminal voltage Vb, and the solid line a represents the measured discharge characteristic (Vb
-Ib characteristic), and a broken line d indicates an approximate characteristic of the discharge characteristic.

For example, in a discharge region of a large current, such as when starting a motor, this discharge characteristic can be approximated by a straight line (broken line d). Further, the electromotive force Eo of the battery is obtained from the value obtained by setting Ib = 0 of the discharge characteristic approximated by the straight line (broken line d), and the dead short current Is obtained by short-circuiting the battery is the discharge approximated by the straight line (broken line d). It is determined from the value of the characteristic Vb = 0.

The dead short current Is and the electromotive force E
Multiplying by o gives Po four times the maximum power that can be drawn from the battery, which can be represented by the area of b. The area of the portion c is Po / 4
, And corresponds to the maximum output of the battery, and this area is the remaining capacity of the battery. The remaining battery capacity is used to prevent the battery from running out and to predict the time for replacement.

[0007]

SUMMARY OF THE INVENTION However, Japanese Patent Application Laid-Open
The conventional battery remaining capacity detecting device disclosed in Japanese Patent Publication No. 235334 corrects a power supply voltage that varies depending on the presence or absence of a load, and compares the corrected power supply voltage with a predetermined value to determine the remaining battery capacity. However, when the temperature is high with the same load, the power supply voltage is high, and when the temperature is low, the power supply voltage is detected low, and the power supply voltage fluctuates due to temperature changes. There is a problem that an error occurs depending on the time. There is also a problem in that the power supply voltage fluctuates in a transient state when the load current rapidly increases and decreases, and an error occurs in the transient state of the load current in detecting the remaining capacity of the battery.

Further, the conventional battery remaining capacity detection method disclosed in Japanese Patent Publication No. 1-39069 detects a battery discharge current and a battery terminal voltage during a large current discharge, and substitutes them into a function representing a correlation. Although the present battery remaining capacity is calculated, the battery terminal voltage during large current discharge has a problem that the battery remaining capacity cannot be accurately detected because the power supply voltage fluctuates due to a temperature change. There is also a problem in that the power supply voltage fluctuates in a transient state when the load current rapidly increases and decreases, and an error occurs in the transient state of the load current in detecting the remaining capacity of the battery.

The present invention has been made to solve such a problem, and an object of the present invention is to calculate a reference voltage by detecting a surface temperature of a lithium ion battery, a terminal voltage when no load is applied, and a load current. The reference voltage in the transient state at the time of sudden increase and decrease of the load current is corrected by a coefficient corresponding to the transient state of the load current, the remaining capacity is calculated by comparing with the current terminal voltage, and the detection accuracy of the remaining capacity is calculated. Is to raise.

[0010]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, a lithium-ion battery remaining capacity detecting apparatus according to the present invention comprises a load current detecting means for detecting a load current of a lithium-ion battery, and a terminal voltage of a battery. And a terminal voltage detecting means for detecting the remaining temperature of the battery based on the load current, the terminal voltage and the surface temperature. The remaining capacity calculating means for calculating the remaining capacity is provided.

[0011] A remaining capacity detection device for a lithium ion battery according to the present invention includes a load current detection means for detecting a load current of the lithium ion battery, and a terminal voltage detection means for detecting a terminal voltage of the battery. The remaining capacity detecting device includes a surface temperature detecting means for detecting a surface temperature of the battery, and a remaining capacity calculating means for calculating the remaining capacity of the battery based on the load current, the terminal voltage and the surface temperature. Even when the temperature changes, the remaining capacity can be accurately detected.

Further, the remaining capacity calculating means according to the present invention comprises:
Reference voltage calculation means for calculating a reference voltage based on load current, surface temperature, and terminal voltage at no load, correction calculation means for correcting the reference voltage when the load current increases or decreases, and It is characterized by comprising comparison calculating means for calculating the remaining capacity of the battery by comparing the detected terminal voltage with the corrected reference voltage, and display means for displaying the remaining capacity.

The remaining capacity calculating means according to the present invention comprises: a reference voltage calculating means for calculating a reference voltage based on a load current, a surface temperature, and a terminal voltage at no load; and a correction means for correcting the reference voltage when the load current increases or decreases rapidly. Correction calculating means for comparing the terminal voltage detected when the load current sharply increases and decreases with the corrected reference voltage to calculate the remaining capacity of the battery, and display means for displaying the remaining capacity. Therefore, the remaining capacity can be accurately detected and displayed.

Further, the correction calculating means according to the present invention comprises:
A correction coefficient setting means for setting different correction coefficients when the load current sharply increases and decreases, and a calculation means for calculating each correction coefficient and a reference voltage, and corrects the reference voltage when the load current sharply increases and decreases. It is characterized by the following.

The correction calculation means according to the present invention includes: correction coefficient setting means for setting different correction coefficients when the load current is rapidly increased and decreased; and calculation means for calculating each correction coefficient and a reference voltage. Since the reference voltage is corrected when the load current sharply increases or decreases, the remaining capacity of the battery can be accurately detected in real time even in a transient state when the load current sharply increases or decreases.

[0016]

Embodiments of the present invention will be described below with reference to the accompanying drawings. Note that the present invention detects a surface temperature, a terminal voltage, and a load current of a lithium ion battery to calculate a reference voltage, and corrects the calculated reference voltage with a coefficient corresponding to a transient state of the load current to detect a detected terminal. It detects the remaining capacity of the lithium ion battery more accurately than the voltage.

FIG. 1 is an overall block diagram of a device for detecting the remaining capacity of a lithium ion battery according to the present invention. In FIG. 1, a remaining capacity detection device 1 for a lithium ion battery includes a lithium ion battery 2, a surface temperature detection unit 4, a load current detection unit 5, a terminal voltage detection unit 6, and a remaining capacity calculation unit 7.

The load 3 is supplied with the lithium ion battery 2 via a switch (not shown), and the terminal voltage is detected by the terminal voltage detecting means 6 when there is no load or when there is a load.

The lithium-ion battery 2 is a large-capacity, small-sized, lightweight, long-life secondary battery capable of charging and discharging the battery. The lithium-ion battery 2 has an electromotive force of about 3.6 V (at load) at normal temperature, and supplies the terminal voltage Va to the load and the terminal voltage detection means 6. The load 3 is connected to the lithium ion battery 2 such as a motor, and consumes the load current Id. The load current Id changes depending on the operation state of the load 3.

The surface temperature detecting means 4 is composed of a temperature sensor such as a thermistor and an arithmetic unit. The thermistor (temperature sensor) Rtx is placed in contact with the surface of the lithium ion battery 2 and the surface temperature of the lithium ion battery 2 is set. Changes, the resistance value of the thermistor Rtx changes. This change in the resistance value is detected, calculated as a temperature resistance voltage value Vth by an arithmetic unit and converted into a voltage value corresponding to the temperature, and the remaining capacity calculation means as the surface temperature Vt. 7

The load current detecting means 5 is composed of a resistor, a differential amplifier and the like.
d is detected by a resistor for current detection, converted into an appropriate voltage value by a differential amplifier, and the converted voltage value is supplied to the remaining capacity calculation means 7 as a load current signal Vi.

The terminal voltage detecting means 6 is composed of an operational amplifier or the like, and has a terminal voltage V supplied from the lithium ion battery 2.
a into a corresponding voltage, and a terminal voltage signal Vd (Vd
o, Vds) are supplied to the remaining capacity calculating means 7. In the terminal voltage signal Vd (Vdo, Vds), the terminal voltage signal at no load is Vdo, and the terminal voltage signal at an arbitrary load (at load) is Vds.

The remaining capacity calculating means 7 is composed of various arithmetic means, processing means, memories or analog circuits such as operational amplifiers based on a microprocessor.
Temperature Vt supplied from the load current signal Vi supplied from the load current detecting means 5 and the terminal voltage detecting means 6
Calculates the reference voltage of the lithium ion battery 2 and corrects the reference voltage based on the terminal voltage signal Vd (Vdo, Vds) supplied from the controller, and calculates and displays the remaining capacity of the lithium ion battery 2.

FIG. 2 is a block diagram of a main part of the remaining capacity calculating means according to the present invention. In FIG. 2, the remaining capacity calculation means 7 includes a reference voltage calculation means 8, a correction calculation means 9, a comparison calculation means 10, and a display means 11.

The reference voltage calculating means 8 is composed of an operational amplifier and the like.
t, the load current signal V supplied from the load current detecting means 5
The reference voltage of the lithium ion battery 2 is calculated based on i and the no-load terminal voltage signal Vdo supplied from the terminal voltage detection means 6, and the reference voltage Bc is supplied to the correction calculation means 9.

The correction calculating means 9 is composed of an operational amplifier or the like, and calculates the reference voltage Bc supplied from the reference voltage calculating means 8 by respective coefficients set when the load current Id increases or decreases rapidly. The correction voltage Vc is supplied to the comparison calculation means 10.

The comparison / calculation means 10 is composed of a computing unit such as a comparator or a subtractor, and is supplied from the terminal voltage detecting means 6 at an arbitrary load supplied from the terminal voltage detecting means 6 and from the correction computing means 9. Comparing with the correction voltage Vc, when the terminal voltage signal Vds is equal to or higher than the correction voltage Vc (Vds ≧ Vc), for example, the H-level calculation signal Vf is supplied to the display unit 11.

When the terminal voltage signal Vds is lower than the correction voltage Vc (Vds <Vc), the comparison calculating means 10 supplies, for example, an L-level calculation signal Vf to the display means 11.

The display means 11 is composed of an audible display such as a buzzer or a visual display such as an LED or a liquid crystal. Based on the H-level or L-level calculation signal Vf supplied from the comparison calculation means 10, a voice or a character is displayed. The remaining capacity of the lithium ion battery 2 is displayed in a picture or the like. The display means 11 turns on a visible indicator such as an LED or a liquid crystal when the H level calculation signal Vf is supplied to indicate that there is remaining capacity, and displays the LED or the like when the L level calculation signal Vf is supplied. Turn off the visible display such as liquid crystal to notify that there is no remaining capacity.

FIG. 3 is a characteristic diagram of the reference voltage of the lithium ion battery according to the present invention. In FIG. 3, the load current Id was set in the X-axis direction, the reference voltage Bc was set in the Y-axis direction, and the battery surface temperature Vt was set in the Z-axis direction, and the load current Id was changed from 0 A to the maximum current (for example, 50 A). FIG. 6 is a characteristic diagram of the reference voltage Bc at the time and when the surface temperature Vt of the battery is changed from −20 ° C. to 80 ° C. The reference voltage Bc refers to the remaining capacity of the lithium ion battery 2 and is a voltage that can be actually supplied to a load.

From this characteristic diagram, it can be seen that the reference voltage Bc has a small change with respect to the surface temperature Vt of the lithium ion battery 2 when the load current Id of the lithium ion battery 2 is small, and the reference voltage Bc increases when the load current Id increases. The change with respect to Vt is large. Also, the reference voltage Bc
Becomes low when the load current Id of the lithium ion battery 2 is large, and becomes high when the load current Id is small.
Further, when the load current Id is 0 A (when no load is applied), the reference voltage Bc has almost no effect even if the surface temperature Vt of the battery changes, and has a substantially constant value.

For example, the reference voltage Bc at the point E is such that the load current Id is 30 A and the battery surface temperature Vt is 20 ° C.
3.6V. As described above, the reference voltage Bc is obtained from the characteristic diagram when the load current Id and the surface temperature Vt of the battery are set.

FIG. 4 shows an embodiment of the analog circuit of the reference voltage calculating means according to the present invention. 4, the reference voltage calculation means 18 includes resistors R1 and R2, thermistors (temperature sensors) Rt1 and Rt2, an operational amplifier Op1, and a stabilized power supply Vo.

The stabilized power supply Vo is a power supply whose voltage does not change even if the load changes, and is connected to the operational amplifier Op through the resistor R2.
1 to supply a current to the non-inverting input terminal (+ terminal) and the thermistor (temperature sensor) Rt2. Thermistor (temperature sensor) Rt1 and thermistor (temperature sensor) Rt2
Is installed in contact with the surface of the lithium ion battery 2 and detects a change in the battery surface temperature as a change in the resistance value.

Thermistor (temperature sensor) Rt1
Is the output terminal of the operational amplifier Op1 and the operational amplifier Op1.
Connected to the inverting input terminal (− side terminal) of the above circuit to form a feedback circuit. The thermistor (temperature sensor) Rt2 is connected between the non-inverting input terminal (+ terminal) of the operational amplifier Op1 and GND (ground).

The operational amplifier Op1 forms an amplifier circuit having an amplification factor represented by the value of Rt1 / R1 by the resistor R1 and the thermistor (temperature sensor) Rt1. The amplification factor of this amplifying circuit changes in proportion to the resistance value when the resistance value of the thermistor Rt1 changes according to the temperature.

A thermistor (temperature sensor) at normal temperature
The voltage across Rt2 becomes the reference voltage of the battery at no load, changes when the surface temperature of the lithium ion battery 2 changes, and the input of the non-inverting input terminal (+ terminal) of the operational amplifier Op1 changes.

The constants of the resistor, thermistor, etc. are obtained by applying the characteristic shown in FIG. 3 to the non-inverting input terminal (+ terminal) of the operational amplifier Op1 when the battery surface temperature Vt is normal temperature and the load current Id is 0 A (no load). When, for example, 3.9 V of the numerical value obtained from the figure is input, 3.9 V is output from the output terminal of the operational amplifier Op1.
V is set to be output as the reference voltage Bc.

The constant of the resistor, thermistor, etc. is such that when the battery surface temperature Vt is normal temperature and the load current Id is the maximum current (for example, 50 A), the load current signal Vi from the load current detecting means 5 is the resistor R1. Is supplied to the inverting input terminal (-side terminal) of the operational amplifier Op1 via the
The output terminal of p1 is set to output, for example, 3.5 V as the reference voltage Bc.

When the constant of the resistor, thermistor and the like is set as described above, when the load current Id is the maximum current (for example, 50 A), the surface temperature Vt of the lithium ion battery 2 is 0 ° C. to 80 ° C. 3.0V
It changes within a range of ３3.9 V.

The reference voltage Bc is such that the load current Id is zero.
Surface temperature V of lithium ion battery 2 at A (no load)
When t changes within the range of 0 ° C. to 80 ° C., the thermistor Rt
1 and Rt2 change, but hardly changes from the output voltage 3.9V of the operational amplifier Op1.

The reference voltage calculating means 8 shown in FIG. 2 is provided with the surface temperature Vt and the load current detecting means 5 from the surface temperature detecting means 4.
Supplies the load current signal Vi from the terminal voltage detection means 6 and the terminal voltage signal Vdo at the time of no load from the terminal voltage detection means 6, but the reference voltage calculation means 18 supplies only the load current signal Vi from the load current detection means 5. The surface temperature Vt is determined by the thermistors Rt1 and Rt2, and the terminal voltage signal Vdo during no load is controlled by the stabilized power supply Vo, the resistor R2, and the thermistor Rt.
It is created from t2.

FIG. 5 shows an embodiment of the analog circuit of the correction operation means according to the present invention. In FIG. 5, the correction calculating means 19 includes resistors R21 and R22, a diode D21,
D22, an arithmetic means 20 having an operational amplifier Op2, and a correction coefficient setting means 21 having resistors R23, R24 and a capacitor C21.

The calculating means 20 receives the reference voltage Bc supplied from the reference voltage calculating means 8 and receives the operational amplifier Op2.
, A calculation signal proportional to the reference voltage Bc (for example, proportional coefficient 1) is supplied to the correction coefficient setting means 21.

The correction coefficient setting means 21 comprises a resistor R23 and a capacitor C21 or a resistor R24 and a capacitor C2.
1 and each time constant (τ = R23 * C21
Alternatively, a correction coefficient of τ = R24 * C21) is set, the operation signal supplied from the operation means 20 is corrected by the correction coefficient, and the correction voltage Vc is supplied to the comparison calculation means 10. The resistance values of the resistors R23 and R24 are R24 >> R23
Set to be.

When the load current Id decreases rapidly (from 50 A to 0 A in a short time), the correction calculating means 19 applies the reference voltage Bc that has increased rapidly (3 V to 3.9 V) to the capacitor C 21 via the resistor R 24. The current is supplied and the time of the set correction coefficient (time constant τ = R24 * C21) (about 120
In 3 seconds, the correction voltage Vc that increases from 3 V to 3.9 V is supplied to the comparison calculation means 10.

The correction calculating means 19 calculates the load current Id
Rapidly increases (0A → 50A in a short time), the reference voltage Bc rapidly decreases (3.9V → 3V), and the electric charge charged in the capacitor C21 is reduced by the resistors R23, D22,
Discharged through the output circuit of the operational amplifier Op2, the electric charge of the capacitor C21 is discharged for a time (several seconds) of a set correction coefficient (time constant τ = R23 * C21), and 3.9V → 3
The correction voltage Vc falling to V is supplied to the comparison calculation means 10.

It should be noted that the correction calculating means 19 calculates the load current Id
When there is no rapid increase or decrease in the value, a calculation signal corresponding to the reference voltage Bc is output from the calculation means 20 and the correction coefficient setting means 21
Supplies the operation signal as it is to the comparison calculation means 10 as the correction voltage Vc without performing the correction.

As described above, the characteristics of the lithium ion battery are such that when the load current Id flows rapidly, the voltage instantaneously drops and converges immediately, and when the load current Id decreases rapidly, the voltage rises with a constant time constant. Therefore, when the reference voltage Bc is corrected by the respective coefficients when the load current Id increases and decreases, the remaining capacity of the lithium ion battery can be calculated accurately.

In the configuration of the above embodiment, for example, a digital circuit is provided with storage means, arithmetic means, etc., and the reference voltage and the correction coefficient are stored in advance in the storage means, so as to match the transient state of the load current. Alternatively, the corresponding reference voltage and correction coefficient may be read from the storage means and operated to correct the reference voltage.

FIG. 6 shows the reference voltage Bc of the lithium ion battery 2 when the load current Id according to the present invention increases or decreases rapidly.
FIG. 7 is a graph showing a time lapse characteristic of a correction voltage Vc. FIG. 6 (A)
Means that the load current Id decreases sharply (for example, 50
The relationship between the reference voltage Bc (shown by a solid line) and the correction voltage Vc (shown by a broken line) when A → 0A) is shown. FIG. 6 (B)
Indicates that the load current Id sharply increases (for example, 0 A
The relationship between the reference voltage Bc (shown by a solid line) and the correction voltage Vc (shown by a broken line) at the time of (50 A) is shown.

In FIG. 6A, the reference voltage Bc (shown by a solid line) sharply rises (for example, 3V → 0A) due to a sudden decrease in the load current Id (for example, 50A → 0A in a short time).
3.9 V), and as described with reference to FIG.
And outputs the corrected voltage Vc. This correction voltage V
c (indicated by a broken line) increases with a constant time constant (about 120 seconds) that converges at about 3.9V.

In FIG. 6B, the reference voltage Bc
(Shown by a solid line) indicates a sudden increase in the load current Id (for example,
It falls rapidly by 0A → 50A in a short time (for example,
3.9V → 3V), and outputs the correction voltage Vc corrected by the correction calculation unit 19 as described with reference to FIG.

The correction voltage Vc (shown by a broken line) is about 3 V
It falls rapidly (within a few seconds). Therefore, the correction voltage Vc (shown by a broken line) corrects the reference voltage Bc so as to increase with a constant time constant (about 120 seconds) when the load current Id decreases rapidly, and the load current Id sharply increases. When increasing, the remaining capacity can be accurately calculated in accordance with the characteristics of the lithium-ion battery 2 in the transient state of the increase or decrease of the load current by correcting with a predetermined coefficient regardless of the time.

[0055]

As described above, the apparatus for detecting the remaining capacity of a lithium ion battery according to the present invention includes a load current detecting means for detecting a load current of the lithium ion battery, and a terminal voltage detecting means for detecting a terminal voltage of the battery. Means for detecting the remaining temperature of the battery, and calculating the remaining capacity of the battery based on the load current, the terminal voltage, and the surface temperature. Since the remaining capacity calculating means is provided, the remaining capacity can be detected accurately with a simple configuration even if the load and temperature change, and the reliability of the apparatus can be improved.

Further, the remaining capacity calculating means according to the present invention comprises:
Reference voltage calculation means for calculating a reference voltage based on load current, surface temperature, and terminal voltage at no load, correction calculation means for correcting the reference voltage when the load current increases or decreases, and A comparison calculation unit for comparing the detected terminal voltage with the corrected reference voltage to calculate the remaining capacity of the battery, and a display unit for displaying the remaining capacity are provided, so that the remaining capacity can be accurately detected and displayed. it can.

Further, the correction calculating means according to the present invention comprises:
A correction coefficient setting means for setting different correction coefficients when the load current sharply increases and decreases, and a calculation means for calculating each correction coefficient and a reference voltage, and corrects the reference voltage when the load current sharply increases and decreases. Therefore, even in a transient state when the load current sharply increases or decreases, the remaining capacity of the battery can be accurately detected in real time, and the detection accuracy can be improved.

[Brief description of the drawings]

FIG. 1 is an overall block configuration diagram of an apparatus for detecting a remaining capacity of a lithium ion battery according to the present invention.

FIG. 2 is a block diagram of a main part of a remaining capacity calculating unit according to the present invention.

FIG. 3 is a characteristic diagram of a reference voltage of the lithium ion battery according to the present invention.

FIG. 4 is an embodiment of an analog circuit of a reference voltage calculating means according to the present invention;

FIG. 5 is a diagram illustrating an embodiment of an analog circuit of a correction operation unit according to the present invention;

FIG. 6 shows the reference voltage Bc and the correction voltage V of the lithium ion battery when the load current Id is rapidly increased and decreased according to the present invention.
Time lapse characteristic diagram of c

FIG. 7 is a characteristic diagram showing a correlation between a battery discharge current and a terminal voltage for calculating a conventional battery remaining capacity disclosed in Japanese Patent Publication No. 1-39069.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Remaining capacity detection device of lithium ion battery, 2 ... Lithium ion battery, 3 ... Load, 4 ... Surface temperature detecting means, 5 ...
Load current detecting means, 6 ... terminal voltage detecting means, 7 ... remaining capacity calculating means, 8, 18 ... reference voltage calculating means, 9, 19 ... correction calculating means, 10 ... comparative calculating means, 11 ... display means, 2
0: calculation means, 21: correction coefficient setting means.

Continued on the front page (72) Inventor Toshiyuki Kubo 1-10-1, Shinsayama, Sayama City, Saitama Prefecture Honda Engineering Co., Ltd. (72) Inventor Hiroki Tabira 1-10-1, Shinsayama, Sayama City, Saitama Honda Engineering Co., Ltd. In-company (72) Inventor Toritsu Kuwahara 1-10-1 Shinsayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. (72) Inventor Teruyuki Oka 1-1-10 Shin-Sayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. (72) Inventor Satoshi Tabuchi 1-10-1 Shinsayama, Sayama-shi, Saitama Honda Engineering Co., Ltd. F-term (reference) 2G016 CA00 CB11 CB12 CB13 CB21 CC04 CC06 CC13 CD09 CD10 CD14 CE01 CE02 CE07 5G003 BA01 CB01 EA05 5H030 AA08 AA10 AS20 FF22 FF42 FF44

Claims (3)

[Claims] 1. A device for detecting a remaining capacity of a lithium ion battery, comprising: load current detecting means for detecting a load current of a lithium ion battery; and terminal voltage detecting means for detecting a terminal voltage of the battery. A lithium-ion battery including surface temperature detection means for detecting a temperature, and remaining capacity calculation means for calculating the remaining capacity of the battery based on the load current, the terminal voltage, and the surface temperature. Remaining capacity detection device. 2. The method according to claim 1, wherein the remaining capacity calculation unit calculates the load current,
A reference voltage calculating means for calculating a reference voltage based on the surface temperature and the terminal voltage at the time of no load; a correction calculating means for correcting the reference voltage when the load current sharply increases and decreases; and a sudden increase and decrease of the load current. 2. The battery control apparatus according to claim 1, further comprising: a comparison calculating unit configured to compare the terminal voltage detected at that time with the corrected reference voltage to calculate a remaining capacity of the battery, and a display unit displaying the remaining capacity. For detecting remaining capacity of lithium-ion batteries. 3. The correction calculation means includes: correction coefficient setting means for setting different correction coefficients when the load current is rapidly increased and decreased; and calculation means for calculating each correction coefficient and a reference voltage. 3. The apparatus according to claim 2, wherein the reference voltage is corrected when the load current increases or decreases abruptly.