JPH07169510A - Remaining capacity detector on ni-mh battery - Google Patents

Abstract

PURPOSE:To accurately and easily detect the remaining capacity of a battery in real time by installing each detecting means of the deterioration degree of the battery, output power, and discharge amount, a correction means based on correlations and them, and an arithmetic means. CONSTITUTION:When a Ni-MH battery 1 for an electric vehicle, for example, is charged with a charger 6, a control unit 5 finds a capacity decreased amount CL corresponding to a deterioration rate with a means 20 which gets hold a deterioration degree from the internal resistance of the battery 1 in a deteriorated capacity holding unit 13. A means 22 which detects a discharged amount SIGMACD from the start of discharge up to now and a means 15 which finds a capacity decreased amount CO according to the present output power are arranged. The present remaining capacity CR of the battery 1 is obtained in an arithmetic unit 14, based on the formula, CR=(CI-CO.L-CL).TC-SIGMACD and displayed on a display 8. In the formula, CI shows the initial capacity at the start of discharge, L shows a correction factor of CO according to deterioration degree, and TC is a correction factor of battery temperature.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting the remaining capacity of a Ni-MH (nickel-metal hydride) battery mounted on an electric vehicle or the like.

[0002]

2. Description of the Related Art In recent years, Ni-MH batteries, which are one of rechargeable secondary batteries, have been used in various devices such as electric vehicles because of their high capacity, good charge / discharge performance, and cleanliness. It is attracting attention as a secondary battery.

In a device using this type of secondary battery (hereinafter referred to as a battery) as an energy source, for example, an electric vehicle, the remaining capacity of the battery (the amount of electricity that can be discharged) is changed by some method. It is important to detect in real time. And, as the detection method,
The discharge current is detected every moment from the start of battery discharge, and the accumulated current is detected by accumulating the discharge current.By subtracting this from the initial capacity at the start of battery discharge, the current remaining amount is calculated. It is generally known to detect the capacity by analogy. In addition, upon such detection, it is generally known that an appropriate correction is made according to the temperature of the battery to improve the detection accuracy of the remaining capacity.

On the other hand, according to the knowledge of the present inventors, the substantial remaining capacity of the battery also changes depending on the output power at the time of its discharge, and the larger the output power, the lower the actual remaining capacity. Therefore, the applicant of the present application detects the remaining capacity of the battery based on the above-described detection method, and corrects the remaining capacity of the battery according to the output power of the battery to accurately detect the substantial remaining capacity of the battery. The above was proposed (see Japanese Patent Application No. 5-137734).

By the way, according to the further knowledge of the present inventors, the substantial remaining capacity of the battery is as described above when the battery is in a state close to a new state (a state in which the number of charge / discharge cycles is relatively small). Although the remaining capacity of the battery can be detected relatively accurately by performing the correction according to the output power of the battery, the charging and discharging are repeated, and when the deterioration of the battery progresses to some extent, the deterioration of the battery is accompanied by the progress of the deterioration. The actual remaining capacity of the battery is reduced.

Therefore, the actual remaining capacity of the battery is
For more accurate detection, it is preferable to perform detection in consideration of the degree of deterioration of the battery.

However, in the past, there was no method for accurately grasping the degree of deterioration of the battery, so that it was difficult to detect the remaining capacity in consideration of the degree of deterioration as described above.

On the other hand, according to the present invention, in the Ni-MH battery, when the internal resistance value of the battery is detected from the voltage change amount and the charging current value when the battery is charged, the internal resistance value and the charging current value are detected. It was found that the degree of deterioration of the battery is closely related to the deterioration state of the battery at the time, and the degree of deterioration of the battery can be grasped from the internal resistance value, and this was previously proposed (see Japanese Patent Application No. 5-157170). .

In view of such a background, the present inventors have made various studies, and as a result, in the Ni-MH battery, the degree of deterioration of the battery is grasped from the internal resistance value when the battery is charged. However, it has been found that the actual remaining capacity of the battery can be detected more accurately by performing an appropriate process according to the deterioration degree, the output power amount, and the like.

[0010]

In view of the above background, the present invention can accurately and easily detect the remaining capacity of a Ni-MH battery in real time in consideration of its deterioration degree and output power at the time of discharging. An object is to provide a remaining capacity detecting device.

[0011]

According to the findings based on various studies by the present inventors, the substantial remaining capacity of a Ni-MH battery during discharge starts discharge when the degree of deterioration of the battery increases. It is smaller than the value obtained by subtracting the discharge amount up to the present from the initial capacity at the time, and the reduced capacity has a certain correlation with the degree of deterioration of the battery. Then, the substantially remaining capacity is smaller than a value obtained by subtracting the discharge amount up to the present from the initial capacity at the time of discharge start when the output power of the battery increases, and the decrease in the capacity also becomes equal to the output power of the battery. There is a certain correlation between them, and the amount of capacity reduction due to the output power is affected by the degree of deterioration of the battery.

Therefore, in order to achieve the above object, the present invention detects the internal resistance value of the Ni-MH battery from the voltage change amount and the charging current value at the time of charging and determines the internal resistance value. A deterioration degree grasping means for grasping the current deterioration degree of the battery, an output power detecting means for detecting an output power at the time of discharging after charging the battery, and an amount of discharge of the battery from the start of the discharging Based on a predetermined correlation between the degree of deterioration of the battery and the amount of decrease in the capacity of the battery, the capacity of the battery at the current degree of deterioration grasped by the degree of deterioration grasping means Deteriorated capacity grasping means for obtaining a decrease amount, and the output power detecting means based on a predetermined correlation between the output power when the battery is discharged and the capacity decrease amount of the battery. Based on the issued and output capacitance detection means for determining the capacity decrease in the battery at the current output power, a predetermined correlation between the degree of deterioration of the capacitive decrease corresponding to the output power of the battery the battery,
Output capacity correction means for correcting the capacity decrease amount obtained by the output capacity grasping means according to the current deterioration degree of the battery obtained by the deterioration degree grasping means, and the initial capacity at the start of discharging the battery, Calculation for subtracting the discharge amount detected by the discharge amount detecting means, the capacity decrease amount obtained by the deteriorated capacity grasping means, and the capacity decrease amount according to the output power corrected by the output capacity correcting means. And a means for detecting the value obtained by the arithmetic means as the current remaining capacity of the battery.

Further, a temperature detecting means for detecting a temperature of the battery during discharging, a capacity decrease amount according to the output power corrected by the output capacity correcting means from an initial capacity of the battery, and the deteriorated capacity grasping means. And a temperature correction unit that corrects a value obtained by subtracting the capacity reduction amount obtained according to the temperature detected by the temperature detection unit, and the calculation unit is a value obtained by the temperature correction unit. It is characterized in that the current remaining capacity of the battery is obtained by subtracting the discharge amount detected by the discharge amount detecting means from.

Further, the present invention is characterized by further comprising a remaining capacity display means for displaying the remaining capacity of the battery obtained by the calculation means by a bar graph.

Further, the remaining capacity display means is configured by adding the capacity decrease amount according to the output power corrected by the output capacity correction means and the capacity decrease amount obtained by the deteriorated capacity grasping means. It is characterized in that a means for displaying the amount of decrease in capacity together with the remaining capacity by a bar graph is provided.

[0016]

According to the present invention, the discharge amount detected by the discharge amount detecting means from the initial capacity of the Ni-MH battery at the start of discharging and the degree of deterioration of the battery ascertained at the time of charging before the start of discharging of the battery. According to the deterioration amount of the battery, the capacity decrease amount obtained by the deterioration capacity grasping means and the capacity decrease amount obtained by the output capacity grasping means according to the output power at the time of discharging the battery are corrected in accordance with the deterioration degree of the battery. It is possible to easily and accurately detect the actual remaining capacity of the battery in consideration of the degree of deterioration of the battery and the influence of the output power, by reducing the It becomes possible to do.

Then, a value obtained by subtracting the capacity decrease amount obtained by correcting the capacity decrease amount according to the output power from the initial capacity of the battery according to the deterioration degree and the capacity decrease amount according to the deterioration degree is calculated as follows. By correcting the remaining capacity of the battery by subtracting the discharge amount from the value obtained by the correction, it becomes possible to detect the remaining capacity in consideration of the influence of the temperature of the battery. It is possible to improve the detection accuracy of.

Further, by displaying the detected remaining capacity of the battery by a bar graph, it becomes possible to easily visually recognize the remaining capacity of the battery.

Furthermore, the remaining capacity is calculated by adding the capacity reduction amount corresponding to the output power corrected by the output capacity correction means and the capacity reduction amount obtained by the deteriorated capacity grasping means. By displaying it with a bar graph together with the actual remaining capacity of the battery,
It becomes possible to visually and easily recognize the amount of capacity reduction corresponding to the output power and the degree of deterioration, and it is possible to adjust the output power of the battery in accordance therewith, and to recognize the time of battery replacement and maintenance.

[0020]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a system configuration diagram of the remaining capacity detection device of this embodiment, and FIGS. 2 to 7 are explanatory diagrams for explaining the operation of the device of FIG.

Referring to FIG. 1, the remaining capacity detecting device of the present embodiment is provided in, for example, an electric vehicle, and 1 is Ni.
-MH battery (hereinafter, simply referred to as battery), 2 is a voltage sensor that detects the output voltage V of the battery 1, 3 is a current sensor that detects the charging / discharging current I of the battery 1, 4 is the temperature T of the battery 1 (hereinafter, A temperature sensor (temperature detecting means) for detecting a battery temperature T), 5 are sensors 2 to 4
A control unit for detecting the remaining capacity of the battery 1 when the battery 1 is discharged in real time based on the detection signal of the battery 1, the charger 6 that is detachably connected through the connection connector 7 when the battery 1 is charged, and 8 is the battery 1 Remaining capacity display (remaining capacity display means) for displaying the remaining capacity, 9 is a running electric motor, 10
Is an electric motor drive control unit for driving and controlling the traveling electric motor 9, and 11 is an accelerator sensor for detecting the accelerator operation amount A by a potentiometer or the like. In the present embodiment, the battery 1 has a full charge capacity of 25 Ah in a new state, for example. As the charger 6, for example, a constant current charging type is used.

The electric motor drive control unit 10 is a battery 1
From the battery 1 to drive the electric motor 9 for driving, and basically, as the accelerator operation amount A detected by the accele sensor 11 is larger, the input power from the battery 1 to the electric motor 9 for traveling (the battery 1 The output electric power of the electric motor 9 is increased to increase the output of the electric motor 9. The driving force of the traveling electric motor 9 is transmitted to driving wheels (not shown) via a power transmission system (not shown).

The control unit 5 is composed of an electronic circuit including a microcomputer and the like, and as its functional configuration, the deterioration degree grasping section 12, the deterioration capacity grasping section (deterioration capacity grasping means) 13, and the output power detection. Part 1
4, output capacity grasping section (output capacity grasping means) 15, discharge amount detecting section 16, calculating section (calculating section) 17, output capacity correcting section (output capacity correcting section) 18, temperature correcting section (temperature correcting section) 19, and The display drive unit 20 is provided. here,
The deterioration degree grasping section 12 constitutes the deterioration degree grasping means 20 together with the respective sensors 2 to 4, and the output power detecting section 14 combines the voltage sensor 2 and the current sensor 3 with the output power detecting means 21. And the discharge amount detection unit 1
Reference numeral 6 constitutes the discharge amount detecting means 22 together with the current sensor 3.

The remaining capacity indicator 8 displays the remaining capacity when the battery 1 is discharged by a bar graph using liquid crystal or the like.

Next, the operation of the remaining capacity detecting device of this embodiment will be described.

First, in the device of the present embodiment, when the battery 1 is charged by the charger 6, the applicant of the present application has filed Japanese Patent Application No.
As suggested in No. 157170, the deterioration degree of the battery 1 is grasped by the deterioration degree grasping section 12 of the control unit 5.

That is, to explain its outline, the charger 6 is connected to the battery 1 through the connector 7 while the driving electric motor 9 is stopped when the electric vehicle is parked or stopped, and in this state, When the charger 6 is started by using a commercial power source or the like, a constant current is passed from the charger 6 to the battery 1 to charge the battery 1. At this time, the output voltage V of the battery 1 detected by the voltage sensor 2 rises as shown in FIG. 2 simultaneously with the start of charging. Then, the deterioration degree grasping section 12 of the control unit 5 detects the variation amount ΔV of the output voltage V at the start of charging via the voltage sensor 2 and the charging current I flowing through the battery 1 via the current sensor 2. Then, the ratio ΔV / I between the variation ΔV of the output voltage V thus detected and the charging current I is obtained.
The value of this ratio ΔV / I is determined by the battery 1 at the start of charging.
Of the internal resistance of the battery 1 and basically changes depending only on the degree of deterioration when the battery 1 is charged. However, the internal resistance value (= ΔV / I) slightly changes depending on not only the degree of deterioration of the battery 1 but also the battery temperature T when the battery temperature T is low. Therefore, in the present embodiment, The deterioration degree grasping unit 12 performs an appropriate correction according to the battery temperature T detected via the temperature sensor 4 to the ratio ΔV.
By applying the value to / I, an internal resistance value R that changes only in accordance with the degree of deterioration of the battery 1 is obtained, and this is output to the deteriorated capacity grasping unit 13 as a parameter indicating the degree of deterioration during charging of the battery 1. Then, the deteriorated capacity grasping unit 13
From the internal resistance value R (deterioration degree) obtained by the deterioration degree grasping unit 12, a corresponding decrease in the capacity of the battery 1 is obtained.

Here, referring to FIG. 3, charging / discharging of battery 1 is repeated under predetermined conditions, and the full charge capacity of battery 1 (the battery 1 can be discharged from the fully charged state at every appropriate number of cycles of the repetition). When the internal resistance value R is obtained while the electric quantity) is actually measured, the number of charge / discharge cycles (the number of times of repeating charge / discharge) of the battery 1 increases and the deterioration of the battery 1 progresses to a certain degree. Battery 1
The actual capacity (the amount of electricity that can actually be discharged from the battery 1) decreases, and in response to this, the internal resistance value R increases as shown in the lower side of the figure.

In this embodiment, the deterioration capacity grasping section 13
3 is provided with the data shown in FIG. 3 as a data showing the correlation between the internal resistance value R and the deterioration degree of the battery 1 by a map, a table, etc., and as described above, the deterioration occurs when the battery 1 is charged. From the internal resistance value R obtained by the degree grasping section 12, the capacity decrease amount C _L of the battery 1 corresponding to the internal resistance value R (deterioration degree) is obtained. For example, in FIG.
Assuming that the internal resistance value R obtained by the deterioration degree grasping unit 12 at the time of charging the battery 1 is 16 mΩ, the capacity decrease amount C _L of the battery 1 obtained by the deterioration capacity grasping unit 13 is 5 Ah. , This means that R = 16
With a deterioration degree of mΩ, the battery temperature of the battery 1 is 30 ° C,
When discharged under the condition of the output power per unit weight of 10 W / kg, it means that the total discharge amount is reduced by 5 Ah as compared with the battery 1 in a new state. The deterioration capacity grasping unit 13 stores and retains the capacity decrease amount C _L according to the deterioration degree of the battery 1 thus obtained in a storage element such as a RAM (not shown), and updates this every time the battery 1 is charged. To do. In the present embodiment, the discharge from the fully charged state of the battery 1 in the new state is performed by, for example, the battery temperature 3
Under the temperature condition of 0 ° C., the output power at the time of discharge is set as the minimum power required to drive the traveling electric motor 9 (in this embodiment, the output power per unit weight of the battery 1 is 10 W / kg). In this case, the capacity of the battery 1 is grasped based on the amount of electricity (temporal integrated value of discharge current) that can be discharged until the output voltage of the battery 1 reaches a predetermined cutoff voltage (for example, 1 V). Therefore, the above-mentioned capacity decrease C
_L indicates the amount of electricity that cannot be discharged when the battery 1 is discharged from the fully charged state under the above conditions.

Next, when the electric vehicle starts to run and the battery 1 starts to discharge, the control unit 5
The output voltage V, the discharge current I, and the battery temperature T of the battery 1 are detected through the sensors 2 to 4 at sufficiently short sampling times, and the remaining capacity of the battery 1 is changed on the basis of the detected data. Is detected as follows.

That is, the discharge amount detector 16 of the control unit 5 integrates the discharge current I detected by the current sensor 3 at each sampling time by the following equation (1), and starts discharging the battery 1. obtaining discharge quantity .SIGMA.C _D to date.

[0032]

[Equation 1]

Here, in the equation (1), Δt is a sampling time.

The output power detection unit 14 of the control unit 5 uses the output voltage V and the discharge current I detected by the voltage sensor 2 and the current sensor 3 at each sampling time to calculate the battery 1 according to the following equation (2). Find the current output power of.

Output power = V · I (2) And the output capacity grasping section 15 of the control unit 5
Is based on the current output power of the battery 1 obtained by the output power detection unit 14 and in accordance with a preset data table as shown in FIG. _Ask for _O.

Here, the data table shown in FIG.
Capacity decrease C according to the deterioration degree_LAs with,
From the fully charged state of battery 1, the battery temperature is 30 ° C.
Output power per unit weight of 10 W / kg
The total amount of discharge obtained when the
If the output power is discharged at various values under the same temperature condition,
Obtained by actually measuring the amount of decrease in the total discharge amount
Is. The basic tendency is that the battery 1
Output power of the
As the amount A increases, the battery 1 that corresponds to the output power
Capacity decrease C _OWill increase. Specifically, the battery 1
The current output power of is 60 W / kg per unit weight
Then, the capacity reduction amount C corresponding to the output power_OIs 2.
6 Ah, which is a full charge of Battery 1
Teri temperature 30 ° C, output power per unit weight 60W /
When discharged under the condition of kg, the total discharge amount is
2.6 Ah compared to when discharged at 10 W / kg
It means that the amount is reduced.

As described above, the discharge amount detector 16
Discharge amount up to now ΣC_DAnd output capacity grasping part
Capacity reduction according to the current output power calculated by 15
Minute C _OAnd before the last charge before the start of discharging the battery 1.
The deterioration of the battery 1 obtained by the deterioration capacity grasping unit 13
Decrease in capacitance C according to the degree of conversion (internal resistance R)_LIs
The calculation unit 17 of the troll unit 5 outputs the calculation unit.
17 is the current remaining capacity C of the battery 1 according to the following equation (3).
_RAsk for.

C _R = (C _I −C _O · L −C _L ) · T _C −ΣC _D (3) Here, in the formula (3), C _I is the initial capacity at the start of discharging the battery 1. , L is an output deterioration correction coefficient for correcting the capacity decrease amount C _O of the battery 1 according to the current output power according to the current deterioration degree (internal resistance value R) of the battery 1, and T _C is the initial capacity C _{From I} , the capacity decrease amount C _O is corrected by the output deterioration correction coefficient L and the capacity decrease amount C _L
Is a temperature correction coefficient for correcting the value obtained by subtracting and, according to the current battery temperature T. The initial capacity C _I , the output deterioration correction coefficient L, and the temperature correction coefficient T _C are set as follows. It

That is, the initial capacity C _I is the battery 1
However, if the battery 1 is in the fully charged state at the start of discharging, the fully charged capacity of the battery 1 in the new state, that is, the new battery 1 in the fully charged state is stored at the battery temperature of 30 °.
C, the total discharge amount obtained when discharged under the condition of output power per unit weight of 10 W / kg is set. Further, when the battery 1 is not charged between the current discharge and the previous discharge of the battery 1, for example, at the end of the last discharge of the battery (at the end of traveling of the electric vehicle), the formula (3 ) Is added to the remaining capacity C _R detected by) and the capacity reduction amount C _L corresponding to the degree of deterioration of the battery 1 at that time, and the value is set as the initial capacity C _I. Further, when the battery 1 is charged between the current discharge and the previous discharge of the battery 1, for example, at the end of the last discharge of the battery (at the end of traveling of the electric vehicle), Formula (3) In advance, a charge amount obtained by adding up the charge current at the time of charging to a value obtained by adding the remaining capacity C _R detected by and the capacity decrease amount C _L according to the degree of deterioration of the battery 1 at that time in advance. A value obtained by adding a value corrected by the determined charging efficiency is set as the initial capacity C _I. still,
The initial capacity C _I may be set based on, for example, the terminal voltage of the battery 1 at the start of discharge, or may be set in consideration of the discharge amount due to self-discharge during parking of the electric vehicle. May be.

The output correction coefficient L is calculated by the output capacity correction unit 18 of the control unit 5 from the current battery 1
Based on the deterioration degree (internal resistance value R) and the current output power of the battery 1, the calculated value of L is given to the calculation unit 17 according to a data table as shown in FIG. .

Here, the data table shown in FIG.
It is set on the basis of actual measurement data of the total discharge amount obtained when the output power is set to various values and discharged from the fully charged state under various values of the internal resistance value R indicating the degree of deterioration of the battery 1. Is. That is, the value obtained by multiplying the value of L given by the data table of FIG. 5 and the capacity decrease amount C _O given by the data table of FIG.
It is the amount of capacity reduction actually measured based on various values of the internal resistance value R and the output power, and when the battery 1 is in the new state (in this embodiment, the internal resistance value R = 2 mΩ), the output power value is arbitrary. On the other hand, the value of L is “1”, and at this time, the measured capacity decrease amount is various as shown in the data table of FIG. 4 for various values of the output power. Then, for example, the output power is 100 W / k with the deterioration degree of the internal resistance value R = 4 mΩ.
The value of L when g is 4.2 is 4.2 with reference to FIG.
This means that when the battery 1 is discharged from the fully charged state with the output power of 100 W / kg at the deterioration degree of the internal resistance value R = 4 mΩ, the new battery 1 has an output power of 100 W / kg. It means that it is 4.2 times as much as the capacity reduction C _O (this is 2.7 Ah with reference to FIG. 4) obtained when the battery is discharged from the fully charged state in kg. Such a basic tendency of the value of L increases as the deterioration of the battery 1 progresses (as the internal resistance value R increases), and the degree of increase increases as the output power increases. When setting such a value of L, the case where the output power is 10 W / kg is used as a reference (L = 1).

The temperature correction coefficient T _C is based on the current battery temperature T (which is detected by the temperature sensor 4) by the temperature correction unit 19 of the control unit 5.
It is calculated according to the data table as shown in FIG. 6, and the calculated value of T _C is given to the calculation unit 17.

Here, the data table shown in FIG. 6 shows the total amount of discharge obtained when the battery 1 in a new state is discharged from the fully charged state at an output power of 10 W / kg under various temperature conditions. The battery temperature 30
The case of ° C is expressed as a reference (T _C = 1). For example, assuming that the battery temperature T is 0 ° C, T _C =
It is 0.93, which means that the total discharge amount obtained when the battery 1 is discharged under the temperature condition of the battery temperature of 0 ° C. is 0.93 times that of the battery temperature of 30 ° C. Means that. The basic tendency of the data table shown in FIG. 6 is that in the low temperature range of the battery temperature T, the temperature correction coefficient T _C decreases as the battery temperature T decreases, that is, the Capacity tends to decrease.

The calculation unit 17 has the initial capacity C _I , the output deterioration correction coefficient L, and the temperature correction coefficient T set as described above.
_{Using C} , according to equation (3) above, the current battery 1
The remaining capacity C _R of Then, the remaining capacity C _R thus obtained is based on the actual measurement data as described above, in consideration of the current deterioration degree (internal resistance value R) of the battery 1, the output power, and the battery temperature T. Since it is obtained, it becomes highly accurate.

Next, the display of the remaining capacity by the remaining capacity indicator 8 will be described.

In the apparatus of this embodiment, the arithmetic unit 1
The remaining capacity C _R and the like obtained as described above according to 7 is displayed on the remaining capacity indicator 8 via the indicator driving unit 20, and at this time, the remaining capacity indicator 8 is displayed as shown in FIGS. In the narrow rectangular frame 23 of b), the current remaining capacity C _R of the battery 1 is displayed by a bar graph by a liquid crystal or the like. In the following description, for convenience of explanation, the case where the battery temperature T is around 30 ° C. (the temperature correction coefficient T _C ≈1) is assumed.

That is, first, referring to FIG.
Before the electric vehicle starts running (before the battery 1 starts discharging), one end of the rectangular frame 23 in the longitudinal direction (see FIG.
The right end in (a) shows "E" indicating the full discharge state of the battery 1.
The MPTY position and the other end (the left end in FIG. 7A) are set to the “FULL” position indicating the fully charged state of the battery 1, and the “EM” is set.
PTY towards FULL "position" from the position "current degree of deterioration of the battery 1 in the bar graph B _L (Fig having a length corresponding to the capacity decrease C _L in response to (the internal resistance value R), stippled portion ) Is displayed, for example, by lighting the liquid crystal in the rectangular frame 23. Further, the current remaining capacity of the battery 1 obtained by the above equation (3) from the tip position of the bar graph _BL toward the "FULL" position. A bar graph B _R (hatched portion in the figure) having a length corresponding to C _R is displayed in a format different from that of the bar graph B _L (for example, lighting display due to different color of liquid crystal). The display of _BL may be performed, for example, by turning off the liquid crystal.

In this case, the total length of the rectangular frame 23 is
Battery 1 full charge capacity, that is, new battery 1
Battery temperature 30 ° C from full charge, per unit weight
Terminal power of the battery 1 under the condition of output power of 10 W / kg
Release until the pressure reaches the specified cutoff voltage (eg 1V).
The total amount of discharge obtained when the battery is charged (time product of discharge current
Corresponding to the calculated value) before the electric vehicle starts running.
If the battery 1 is fully charged, for example, the remaining capacity C_RCorresponding to
Bar graph B_RIs the bar graph B_LFrom the tip position of
Displayed over the entire area up to the "FULL" position
It Then, the capacity decrease C due to deterioration of the battery 1_LTo
Corresponding bar graph B_LFrom the "EMPTY" position of
Is changed according to the current degree of deterioration of the battery 1,
For example, if the battery 1 is new, the capacity decrease C
_LIs "0" (see FIG. 3), the bar graph B_LIs
Not displayed, therefore the remaining capacity C_RBar graph corresponding to
B_ROnly the "EMPTY" position will be displayed.
It The temperature correction coefficient T _CIf ≈ 1, electric vehicle
Before the start of driving, output power = 0,
Reduced capacity C_OIs also “0” (see FIG. 4), and
Discharge amount ΣC_D= 0, it is clear from the above formula (3)
As you can see, bar graph B_L, B_RLength including the length of
That is, from the "EMPTY" position to the bar graph B_R
To the tip position of the battery is the initial capacity C of the battery 1._ITo
Match.

Next, referring to FIG. 7B, an electric vehicle
When the vehicle starts running and the battery 1 starts to discharge,
At some point during discharge, the remaining capacity C_RShowing bargra
B _RThe tip position of the is calculated by the equation (1)
Electricity ΣC_DTo the "EMPTY" position side by the length corresponding to
Moving. And on the "EMPTY" position side,
Capacity decrease C according to the current degree of deterioration of battery 1_LWhen,
Capacity decrease C according to current output power of battery 1_OTo
A value C corrected by the deterioration capacity correction coefficient L_O・ L
Bar graph B having a length corresponding to the total amount of
_OL(The stippled area in the figure) is displayed, and the bar graph B_OLof
Remaining capacity C from the tip position_RBar graph B _RIs displayed
Be done. In this case, bar graph B_RThe length of the battery 1
According to the change of the output power of, in other words, accelerator operation
It changes according to the change of the quantity A, for example, a temporary of an electric vehicle.
When the vehicle is stopped, the output power is 0 and the
Volume reduction C_OIs "0", so bar graph B_OLThe long
Sa is the capacity reduction due to the deterioration of the battery 1 at the present time
Minute C_LThe length is equivalent to. At this time, the remaining capacity C
_RBar graph B_RIs the bar graph B_OLBecomes shorter
The length increases to the "EMPTY" position side by the amount.

In the above explanation, the temperature correction coefficient T _C ≈1
In the case where T _C ≠ 1 such as when the battery temperature T is relatively low, as is clear from the above formula (3), for example, before running the electric vehicle, the battery 1 degradation length of the bar graph B _L indicating a capacity decrease C _L becomes the length T _C times the length of FIGS. 7 (a) by, said bar graph B _L and residual capacity C bar shows the _R graph B _R The total length of the two is T _C times the length of FIG. Further, when the electric vehicle is running, the length of the bar graph B _OL showing the capacity decrease amount according to both the deterioration of the battery 1 and the output power is T _C of the length shown in FIG. 7B.
The length is doubled, and the total length of the bar graph B _OL and the bar graph B _R indicating the remaining capacity C _R is T _C times the length in FIG. 7A.

By performing such a display, the driver of the electric vehicle can easily visually recognize the substantial remaining capacity C _R of the battery 1, and the output power of the battery 1, that is, the other words. If this is done, the actual remaining capacity C _R corresponding to the accelerator operation amount A can be grasped, so it is possible to easily adjust the accelerator operation amount A accordingly and to easily predict the cruising range in the current traveling state. You can In addition, the stop or the like of the electric vehicle, since the capacitance decrease C _L due to deterioration of the battery 1 is displayed by the bar graph B _OL or B _L, knowing the length of the bar graph B _OL or B _L Thus, it is possible to easily recognize the necessity of replacing the battery 1 and the necessity of maintenance.

[0052]

As is apparent from the above description, according to the present invention, when the Ni-MH battery is discharged, the amount of discharge up to the present from the initial capacity at the start of the Ni-MH battery and the charge before the start of discharge of the battery. At the same time, the capacity decrease amount that is recognized according to the deterioration level of the battery and the capacity decrease amount that is obtained by correcting the capacity decrease amount according to the output power when the battery is discharged according to the deterioration level of the battery are reduced. By using the obtained value as the current remaining capacity of the battery, it is possible to accurately and easily detect the actual remaining capacity of the battery in real time with consideration for the degree of deterioration of the battery and the influence of the output power.

Then, the value obtained by subtracting the capacity decrease amount obtained by correcting the capacity decrease amount corresponding to the output power according to the deterioration degree and the capacity decrease amount corresponding to the deterioration degree from the initial capacity of the battery is the battery. By correcting the remaining capacity of the battery by subtracting the discharge amount from the value obtained by the correction, it is possible to detect the remaining capacity in consideration of the influence of the temperature of the battery, It is possible to improve the detection accuracy of the remaining capacity.

Further, by displaying the detected remaining capacity of the battery in the form of a bar graph, it is possible to easily and visually recognize the remaining capacity according to the current operating condition of the battery.

Further, the capacity decrease amount obtained by correcting the capacity decrease amount corresponding to the output power according to the deterioration degree and the capacity decrease amount corresponding to the deterioration degree are added to the remaining capacity and the bar value. By displaying the graph, not only the actual remaining capacity of the battery, but also the amount of capacity decrease according to the output power and the degree of deterioration can be easily visually recognized, thereby adjusting the output power of the battery. Also, it is possible to easily recognize the time of battery replacement and maintenance.

[Brief description of drawings]

FIG. 1 is a system configuration diagram of an example of a remaining capacity detection device of the present invention.

FIG. 2 is an explanatory diagram for explaining the operation of the apparatus of FIG.

FIG. 3 is an explanatory view for explaining the operation of the apparatus of FIG.

FIG. 4 is an explanatory view for explaining the operation of the apparatus of FIG.

5 is an explanatory diagram for explaining the operation of the apparatus in FIG. 1. FIG.

FIG. 6 is an explanatory view for explaining the operation of the apparatus of FIG.

FIG. 7 is an explanatory view for explaining the operation of the apparatus of FIG.

[Explanation of symbols]

1 ... Battery, 4 ... Temperature sensor (temperature detection means), 8 ...
Remaining capacity indicator (remaining capacity displaying means), 13 ... Deteriorated capacity grasping section (deterioration capacity grasping means), 15 ... Output capacity grasping section (output capacity grasping means), 17 ... Calculation section (computing means), 18 ... Output capacity Correction unit (output capacity correction unit), 19 ... Temperature correction unit (temperature correction unit), 20 ... Degradation degree grasping unit, 21 ... Output power detecting unit, 22 ... Discharge amount detecting unit.

Claims (4)

[Claims] 1. A Ni-MH battery detects an internal resistance value of the battery from a voltage change amount and a charging current value at the time of charging, and grasps a current degree of deterioration of the battery based on the internal resistance value. Deterioration degree grasping means, output power detecting means for detecting output power at the time of discharging after charging the battery, discharge amount detecting means for detecting an amount of discharge of the battery from the start of the discharging, and A deterioration capacity grasping means for obtaining a decrease in the capacity of the battery at the current deterioration degree grasped by the deterioration degree grasping means, based on a predetermined correlation between the degree of deterioration and the capacity decrease of the battery; Based on the predetermined correlation between the output power at the time of discharging and the capacity decrease of the battery,
Output capacity grasping means for obtaining a capacity decrease of the battery in the current output power detected by the output power detecting means, and capacity decrease corresponding to the output power of the battery and deterioration degree of the battery are predetermined. Output capacity correction means for correcting the capacity decrease amount obtained by the output capacity grasping means according to the current deterioration degree of the battery obtained by the deterioration degree grasping means, based on the above correlation.
The discharge amount detected by the discharge amount detecting means from the initial capacity at the start of discharge of the battery, the capacity decrease amount obtained by the deteriorated capacity grasping means, and the output corrected by the output capacity correcting means. A remaining capacity detecting device for a Ni-MH battery, comprising: a calculating means for reducing a capacity decrease amount according to electric power, and detecting a value obtained by the calculating means as a current remaining capacity of the battery. 2. A temperature detecting means for detecting a temperature when the battery is discharged, a capacity decrease amount according to the output power corrected from the initial capacity of the battery by the output capacity correcting means, and the deteriorated capacity grasping means. And a temperature correction unit that corrects a value obtained by subtracting the capacity reduction amount obtained according to the temperature detected by the temperature detection unit, and the calculation unit is a value obtained by the temperature correction unit. 2. The remaining capacity detecting device for a Ni-MH battery according to claim 1, wherein the current remaining capacity of the battery is obtained by subtracting the discharging quantity detected by the discharging quantity detecting means from the above. 3. The remaining capacity detecting device for a Ni-MH battery according to claim 1, further comprising a remaining capacity display means for displaying the remaining capacity of the battery obtained by the computing means by a bar graph. 4. The remaining capacity display means is configured by adding a capacity decrease amount according to the output power corrected by the output capacity correction means and the capacity decrease amount obtained by the deteriorated capacity grasping means. 4. The remaining capacity detecting device for a Ni-MH battery according to claim 3, further comprising means for displaying a decrease in capacity together with the remaining capacity by a bar graph.