JPH11135157A - Alkaline battery charging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charging device, capable of adequately charging an alkaline battery by accurately correcting a temperature heated by the charge of the alkaline battery with the temperature of a dummy calorific capacity body, even if the ambient temperature of the alkaline battery is changed sharply. SOLUTION: A dummy battery 20 is arranged in the vicinity of a nickel - hydrogen battery 11 in a battery circuit 10. A microcomputer 50 controls a drive circuit 60 and a charger 70, so that the battery circuit 10 is charged until the difference between a temperature detected with a temperature sensor 30 of the nickel - hydrogen battery 11, and a temperature detected with a temperature sensor 40 of the dummy battery 20 reaches the full charging temperature of the nickel - hydrogen battery 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a charging device for an alkaline battery for an electric vehicle, a hybrid vehicle, and various other industrial equipment.

[0002]

2. Description of the Related Art In recent years, for example, electric vehicles have been receiving attention from the viewpoints of energy saving and emission control. The electric vehicle has a plurality of batteries connected in series and stacked. As the above battery, a nickel-hydrogen battery is advantageous. This is because nickel-hydrogen batteries have a higher energy density than lead batteries.

When a nickel-metal hydride battery is charged by a charger, the charging efficiency of the nickel-metal hydride battery deteriorates at the end of charging the nickel-metal hydride battery. Therefore, the temperature of the nickel-metal hydride battery rises. In response to this, there is a method of determining whether the nickel-metal hydride battery is fully charged by detecting a temperature rise of the nickel-metal hydride battery, and stopping charging by the charger.

[0004]

However, when the charge control is performed using the temperature of the nickel-hydrogen battery as described above,
Depending on the temperature at the start of charging of this nickel-hydrogen battery,
Nickel that determines that the nickel-hydrogen battery is fully charged
The temperature of the hydrogen battery changes. For this reason, nickel
When controlling the charge of the hydrogen battery, the temperature of the nickel-hydrogen battery that is determined to be fully charged must also be changed according to the temperature at the start of charging the nickel-hydrogen battery.

[0005] To address this, the following two methods are known. As a first method, the temporal change rate (dT / dt) of the temperature of the nickel-metal hydride battery is used, and when the change rate (dT / dt) exceeds a threshold, charging of the nickel-metal hydride battery is stopped. This is a method for performing control. In this method, regardless of the temperature at the start of charging of the nickel-metal hydride battery, (dT / dt)
Is increased, the use of (dT / dt) enables control to be performed regardless of the absolute value of the temperature at the start of charging of the nickel-metal hydride battery.

As a second method, a value ΔT obtained by subtracting the environmental temperature from the temperature of the nickel-metal hydride battery is used.
This is a method of performing control to stop charging of the nickel-metal hydride battery when exceeds a threshold value. In this method, the temperature of the nickel-hydrogen battery is corrected by the environmental temperature,
Control can be performed irrespective of the absolute value of the temperature at the start of charging of the nickel-hydrogen battery.

However, when the temperature of the nickel-metal hydride battery becomes high, the charging efficiency of the nickel-metal hydride battery is greatly reduced, or the amount of self-discharge of the nickel-metal hydride battery is increased. For example, as shown in FIG. 7, the dischargeable capacity of a nickel-metal hydride battery (rated capacity 100 Ah) rapidly decreases when the temperature exceeds 40 ° C.

Therefore, when charging a nickel-metal hydride battery, the temperature of the nickel-metal hydride battery is high (40 ° C.).
Is preferably controlled so as not to reach. In addition, since a nickel-hydrogen battery mounted on a vehicle is often exposed to high temperatures in the summer, when the temperature of the nickel-metal hydride battery is high, it is necessary to lower the temperature of the nickel-metal hydride battery by a cooling device such as a fan. .

However, in the first method, nickel-
Since it is not possible to distinguish between a change in the temperature of the nickel-metal hydride battery due to a change in the environmental temperature of the hydrogen battery and a change in the temperature due to charging of the nickel-metal hydride battery,
A problem arises in that charging of the nickel-hydrogen battery is stopped even though the battery is not fully charged. In the second method, since the heat capacity of the nickel-metal hydride battery is large, the change in the temperature of the nickel-metal hydride battery is slower than the change in the environmental temperature of the nickel-metal hydride battery. Therefore,
An appropriate correction cannot be made at the environmental temperature of the nickel-hydrogen battery. For example, if the environmental temperature suddenly decreases during charging of the nickel-metal hydride battery, the difference ΔT between the temperature of the nickel-metal hydride battery and the environmental temperature becomes apparently large, and the charging of the nickel-metal hydride battery is stopped. This causes a problem of being lost.

[0010] In order to cope with the above, the present invention is capable of accurately calculating the heat generation temperature due to the charging of the alkaline battery by the temperature of the dummy heat capacitor even when the environmental temperature of the alkaline battery rapidly changes. It is an object of the present invention to provide a charging device that enables appropriate charging of an alkaline battery by making good corrections.

[0011]

In order to solve the above-mentioned problems, according to the first aspect of the present invention, the dummy heat capacity is disposed near the alkaline battery to be charged by the charging means. Then, the control means charges the alkaline battery until the difference between the detected temperature of the first temperature sensor for the alkaline battery and the detected temperature of the second temperature sensor for the dummy heat capacity reaches a predetermined value indicating the completion of charging of the alkaline battery. To control the charging means.

Here, the temperature of the dummy heat capacity member placed under the same environmental temperature as that of the alkaline battery is a temperature that changes depending on the environmental temperature even when the alkaline battery is charged. Therefore, the difference between the two detected temperatures increases due to only the heat generated by charging the alkaline battery. Therefore, the difference between the two detected temperatures is accurately corrected by the temperature of the dummy heat capacitor so as to cancel the influence of the change in the environmental temperature. Thereby, even if the environmental temperature changes rapidly, the alkaline battery is charged by charging the alkaline battery until the difference between the two detected temperatures reaches the predetermined value.
It can be charged sufficiently.

[0013] According to the second aspect of the present invention, the dummy heat capacity member is disposed near the alkaline battery to be charged by the charging means. The control means controls the alkaline battery until the difference between the temperature detected by the first temperature sensor for the alkaline battery and the temperature detected by the second temperature sensor for the dummy heat capacitor reaches a predetermined rate of change indicating the completion of charging of the alkaline battery. The charging means is controlled so as to be charged.

As described above, even when the alkaline battery is charged using the predetermined change rate instead of the predetermined value described in claim 1, the same operation and effect as in claim 1 can be achieved.
Here, according to the invention described in claim 3, the heat insulating member is:
It is interposed between the alkaline battery and the dummy heat capacity body. As a result, the mutual heat transfer between the alkaline battery and the dummy heat capacity body is reliably shut off, so that the function and effect of the invention of claim 1 or 2 can be further improved.

Further, even when the dummy heat capacity element is an alkaline battery as in the invention according to the fourth aspect, the same operation and effect as the invention according to any one of the first to third aspects can be achieved. . Further, when the dummy heat capacity body is a secondary battery for an auxiliary device of an electric vehicle or a hybrid vehicle as in the invention described in claim 5, it is not necessary to separately prepare a new dummy heat capacity body.

According to the invention, the alkaline battery is a nickel-metal hydride battery. Further, the cooling means controls the temperature of the nickel-hydrogen battery in accordance with the temperature detected by the first temperature sensor so as to maintain the temperature of the nickel-hydrogen battery within a predetermined temperature range capable of maintaining good charging efficiency. -Cool the hydrogen battery. Thereby, the operation and effect of the invention according to any one of claims 1 to 5 can be achieved while maintaining and maintaining the charging efficiency of the nickel-hydrogen battery at a high level.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. FIG. 1 shows an example in which the charging device according to the present invention is applied to a battery circuit 10 for a driving source of an electric vehicle. The battery circuit 10 is mounted on the electric vehicle, and includes a plurality of alkaline batteries 1.
1 are connected in series.

The charging device includes a dummy battery 20 composed of a battery similar to the alkaline battery 11, and the dummy battery 20 is mounted on the electric vehicle near the battery circuit 10. Thereby, the dummy battery 20
It is located in the same environmental temperature range as the environmental temperature of the battery circuit 10. However, when charging the battery circuit 10, the dummy battery 20 is not electrically connected to the battery circuit 10 and does not charge or discharge.

Here, the battery circuit 10 and the dummy battery 20
2 will be described in detail with reference to FIG. 2. As shown in FIG. 2, a plurality of alkaline batteries 11 are arranged at appropriate places in the electric vehicle. In addition, the dummy battery 20
As shown in FIG. 2, through an L-shaped heat insulating plate 21,
It is arranged adjacent to both alkaline batteries 11 in the vicinity.

The dummy battery 20 may be substituted by a heat capacity having the same heat capacity and heat conductivity as the battery circuit 10. Further, the dummy battery 20 may be substituted with a 12V secondary battery for auxiliary equipment of the electric vehicle. This eliminates the need to separately prepare a dummy battery 20. Further, the heat insulating plate 21 may be generally a heat insulating member.

In addition, the charging device includes the two temperature sensors 3
0 and 40 are provided. The temperature sensor 30 is connected to the battery circuit 1
The temperature sensor 30 detects the temperature of the battery circuit 10. The temperature sensor 40 is a dummy battery 2
The temperature sensor 40 detects the temperature of the dummy battery 20. Specifically, the temperature sensors 30 and 40 are inserted into the insertion hole 11a of the nickel-hydrogen battery 11 and the insertion hole 20a of the dummy battery 20 at their terminals 31 and 41, respectively. It is arranged in the circuit 10 and the dummy battery 20 (see FIG. 2).

The microcomputer 50 executes the computer program in accordance with the flowchart shown in FIG. 3, and during this execution, the driving device 6 connected to the charger 70 based on the detected temperatures of the two temperature sensors 30 and 40.
The arithmetic processing for driving 0 is performed. The computer program is stored in the ROM of the microcomputer 50.
Is stored in advance.

The driving device 60 includes the microcomputer 5
Under the control of 0, the operation of the charger 70 is controlled. As a result, the charger 70 operates the battery circuit 1
0 is charged. The control device 80 controls the air cooling action of the air cooling fan 90 on the battery circuit 10. Air cooling fan 9
0 air-cools the battery circuit 10 by its operation. The battery circuit 10 may be cooled by various cooling means without being limited to the air cooling fan 90.

In this embodiment configured as described above,
The microcomputer 50 starts executing the computer program according to the flowchart of FIG. Then
In step 100, the temperature detected by the temperature sensor 30 (hereinafter, referred to as battery temperature Tb) and the temperature detected by the temperature sensor 40 (hereinafter, referred to as dummy temperature Td) are input to the microcomputer 50.

Next, in step 110, if the battery temperature Tb is 40 ° C. or higher, a determination of NO is made. Then, in step 111, the charging of the battery circuit 10 is in a standby state. This is because, as shown in FIG. 7, the dischargeable capacity of the nickel-metal hydride battery 11 rapidly decreases when the environmental temperature of the battery circuit 10, that is, the charging environmental temperature is 40 ° C. or higher.

On the other hand, if the battery temperature Tb is lower than 40 ° C., the determination in step 110 is YES, and in step 112, an operation command for the charger 70 is output to the drive circuit 60. Accordingly, the charger 70 is driven and driven by the drive circuit 60 to start charging the battery circuit 10. Then, in step 113, step 1
A temperature difference (Tb-Td) is calculated based on the battery temperature Tb and the dummy temperature Td at 00.

In step 120, if the temperature difference (Tb-Td) is equal to or less than 10 ° C., a determination of NO is made. Thereafter, the arithmetic processing circulating from step 100 to step 120 is repeated until the temperature difference (Tb−Td)> 10 ° C. In addition, during the repetitive arithmetic processing, the charging of the battery circuit 10 by the charger 70 is continued.

As described above, the charging of the battery circuit 10 is limited until the temperature difference (Tb−Td)> 10 ° C., as seen from the characteristics of the nickel-hydrogen battery 11 shown in FIG. If the temperature difference (Tb−Td) exceeds 10 ° C., the dischargeable capacity of the nickel-metal hydride battery 11 extremely decreases. The temperature of the nickel-hydrogen battery 11 is 10 ° C.
It is considered that the battery will be fully charged in the vicinity.

In the charging process, the controller 80 controls the temperature of the battery circuit 10 to a predetermined allowable range (40 ° C.) based on the temperature detected by the temperature sensor 30 (battery temperature Tb).
The air cooling operation of the air cooling fan 90 is controlled so as to fall within the following range). This corresponds to the battery temperature Tb as shown in FIG.
Is 40 ° C. or higher, the charging efficiency of the nickel-metal hydride battery 11 is greatly reduced.
In order to maintain the charging efficiency of the nickel-metal hydride battery 11 sufficiently high by maintaining the temperature of the nickel-metal hydride battery 11 at 40 ° C. or less during charging in consideration of the remarkable decrease in the dischargeable capacity of the nickel-metal hydride battery 11. It is.

When the determination in step 120 is YES, a charge stop command is output to the drive circuit 60 in step 121. Accordingly, the charger 7
The charging operation of 0 is stopped by the drive circuit 60. As described above, the dummy battery 20 is placed in the same environmental temperature range as the battery circuit 10, that is, the nickel-metal hydride battery 11, and does not charge or discharge even when the nickel-metal hydride battery 11 is charged. For this reason, the temperature of the dummy battery 20 is a temperature that changes only by the environmental temperature even when the nickel-metal hydride battery 11 is charged.

Therefore, the temperature difference (Tb-Td) increases due to only the heat generated by charging the nickel-metal hydride battery 11. Therefore, the temperature difference (Tb−Td)
Is accurately corrected by the temperature of the dummy battery 20 so as to cancel the influence of the change in the environmental temperature. Thereby, even if the environmental temperature changes suddenly, the temperature difference (Tb-T
By charging the nickel-metal hydride battery 11 until d) reaches 10 ° C., the nickel-metal hydride battery 11 can be reliably and sufficiently charged.

In this case, since the heat insulating plate 21 insulates the nickel-hydrogen battery 11 and the dummy battery 20, the mutual temperature between the nickel-hydrogen battery 11 and the dummy battery 20 may be affected. Absent. For this reason, the determination in steps 110 and 120 can be performed with high accuracy. As a result, the temperature difference (Tb-Td) is accurately corrected. Therefore, the nickel-hydrogen battery 11 can be fully charged.

As described above, the temperature of the battery circuit 10 is maintained within the predetermined allowable range by using the air-cooling fan 90 according to the temperature detected by the temperature sensor 30 as described above. It can be done efficiently. Incidentally, when the nickel-hydrogen battery 11 of the battery circuit 10 in the above embodiment was completely discharged and then charged, the data as shown in FIG. 4 was obtained.

FIG. 4 shows the battery temperature Tb, the dummy temperature Td, and the battery circuit 1 when the nickel-hydrogen battery 11 is charged.
0 and the environmental temperature of the dummy battery 20 (hereinafter, environmental temperature Tk).
) Is shown by the respective graphs L1, L2 and L3. However, in order to investigate the effect when the environmental temperature Tk changes suddenly, the environmental temperature Tk was changed from 20 ° C. to 40 ° C.
Was changed in a cycle.

FIG. 4 shows that the battery temperature Tb and the dummy temperature Td are affected by the environmental temperature Tk. Further, based on the data of FIG. 4, the temperature difference (Tb-T
d) (hereinafter referred to as a temperature difference ΔTd) and a difference between the battery temperature Tb and the environmental temperature Tk (hereinafter, a temperature difference ΔTk = (Tb−T
k)), as shown in FIG. 5, were obtained as a graph M1 and a graph M2, respectively.

According to this, the temperature difference ΔTk is equal to the environmental temperature T
It is greatly influenced by k and fluctuates greatly. On the other hand, the temperature difference Δ
At Td, the influence of the environmental temperature Tk is canceled, and it can be seen that the battery temperature Tb rises smoothly at the end of charging the nickel-metal hydride battery 11. For example, the temperature difference ΔT
When it is determined that the nickel-metal hydride battery 11 is fully charged and the charging is stopped when d reaches 10 ° C., when the temperature difference ΔTk is used, the point E shown in FIG.
% Charge), the charging stops.

It should be noted that the second technique described in the prior art of the present specification is used.
In this method, the temperature difference ΔTk is used. However, when the temperature difference ΔTk is used for charging control, malfunction may occur due to the influence of the environmental temperature Tk. On the other hand, the temperature difference ΔT
When d is used, it can be seen that the charging is stopped at the point F shown in FIG. 5 (at about 100% charging).

In the above embodiment, by using the temperature difference ΔTd for the charging control of the battery circuit 10, the charging of the battery circuit 10 is hardly affected by the fluctuation of the environmental temperature Tk.
The rise in temperature due to the influence of charging can be recognized, and charging can be performed accurately. The temperature difference ΔTd at which charging is stopped
Is different depending on the battery, and may be set so that the battery can be controlled to be fully charged. As described above, the nickel-hydrogen battery 11 is fully charged near the temperature difference (Tb-Td) = 10 ° C.

Next, a modification of the above embodiment will be described with reference to FIG. In this modification, step 11 in FIG.
In 3, instead of the temperature difference ΔTd = (Tb−Td),
The temporal change rate {d (ΔTd) / dt} of the temperature difference ΔTd is calculated. Further, in step 120, instead of the temperature difference (Tb−Td), the temporal change rate {d (ΔTd) / dt} of the temperature difference ΔTd or the temporal change rate {d (ΔTk) / dt} of the temperature difference ΔTk. Is adopted. And
{D (ΔTd) / dt}> 10 (° C./min) or Δd
(ΔTk) / dt｝> 12 (° C./min) is determined.

With this, the same operation and effect as the above embodiment can be achieved. Incidentally, the temporal change rate {d (ΔTk) / dt} of the temperature difference ΔTk and the temporal change rate {d (ΔTd) / dt} of the temperature difference ΔTd, and the charge capacity at the rated capacity of the nickel-metal hydride battery 11 ( %), The data shown in FIG. 6 was obtained.

In FIG. 6, a graph Q1 shows the relationship between the time rate of change {d (ΔTk) / dt} and the charge capacity.
The graph Q2 shows the relationship between the temporal change rate {d (ΔTd) / dt} and the charge capacity. According to this, the rate of change Δd
It can be seen that (ΔTd) / dt} is less affected by the environmental temperature Tk than the rate of change {d (ΔTk) / dt}.

For example, the temporal change rate of the temperature difference is 12 (° C.)
/ Min), when the charging of the nickel-metal hydride battery 11 is controlled to stop, the rate of change ｛d (ΔTk)
/ Dt}, the charging of the nickel-metal hydride battery 11 is stopped at the point G shown in FIG. 6 (at the time of charging of about 5%), and the variation of the rate of change {d (ΔTk) / dt} is large. Therefore, it is not suitable for use in charge control. On the other hand, the rate of change Δd
When (ΔTd) / dt} is adopted, the point H shown in FIG.
(At about 103% charge), the charging of the nickel-hydrogen battery 11 is stopped, so that the possibility of malfunction is relatively small.

Therefore, in step 120, the rate of change Δd
Instead of (ΔTk) / dt}, the rate of change {d (ΔTd) /
More preferably, dt｝ is employed. In the practice of the present invention, when an alkaline battery different from the nickel-hydrogen battery 11 is used for the battery circuit 10, if the charging efficiency of the alkaline battery does not significantly decrease due to an increase in temperature, the air-cooling fan 90. May be abolished.

In practicing the present invention, the present invention is not limited to electric vehicles, but may be applied to nickel-hydrogen batteries used in hybrid vehicles and various industrial equipment. In this case, the battery is not limited to the nickel-metal hydride battery but may be an alkaline battery in general.

[Brief description of the drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention.

FIG. 2 is a perspective view showing an arrangement state of a battery circuit and a dummy battery of FIG. 1;

FIG. 3 is a flowchart showing an operation of the microcomputer of FIG. 1;

FIG. 4 is a graph showing temporal changes of respective temperatures Tb, Td, and Tk.

FIG. 5 is a graph showing a temporal change of each temperature difference ΔTd and ΔTk.

FIG. 6 is a diagram illustrating a variation rate of a temperature difference {d (ΔTk) / dt} and a variation rate Δd (ΔT) for describing a modification of the embodiment.
4 is a graph showing the relationship between d) / dt} and the charge capacity of a nickel-metal hydride battery.

FIG. 7 is a graph showing a relationship between an environmental temperature and a dischargeable capacity at the time of charging of a nickel-metal hydride battery.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Battery circuit, 11 ... Nickel-metal hydride battery, 20 ... Dummy battery, 21 ... Heat insulation board, 30, 40 ... Temperature sensor, 5
0: microcomputer, 60: driving device, 70: charger.

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Tomoya Kato 1-1-1, Showa-cho, Kariya-shi, Aichi Pref.

Claims (6)

[Claims] 1. A charging means (60, 70) for charging an alkaline battery (11), a dummy heat capacity member (20) disposed near the alkaline battery, and detecting a temperature of the alkaline battery. A first temperature sensor (30), a second temperature sensor (40) for detecting the temperature of the dummy heat capacitor, and a difference between the respective detected temperatures of the first and second temperature sensors. A control device (112, 120) for controlling the charging means so as to charge the alkaline battery until a predetermined value indicating completion is obtained. 2. A charging means (60, 70) for charging an alkaline battery (11), a dummy heat capacity member (20) disposed near the alkaline battery, and detecting a temperature of the alkaline battery. A first temperature sensor (30), a second temperature sensor (40) for detecting the temperature of the dummy heat capacitor, and a change rate of a difference between respective detected temperatures of the first and second temperature sensors, wherein the rate of change is the alkali-based. A control device (112, 120) for controlling the charging means so as to charge the alkaline battery until a predetermined rate of change indicating completion of charging of the battery is reached. 3. The charging device for an alkaline battery according to claim 1, further comprising a heat insulating member interposed between the alkaline battery and the dummy heat capacity member. 4. The charging device for an alkaline battery according to claim 1, wherein the dummy heat capacity body is an alkaline battery. 5. The charging device for an alkaline battery according to claim 1, wherein the dummy heat capacity member is a secondary battery for an auxiliary device of an electric vehicle or a hybrid vehicle. 6. The alkaline battery is a nickel-metal hydride battery, and the cooling means maintains the temperature of the nickel-metal hydride battery within a predetermined temperature range that can maintain good charging efficiency during the control of the control means. The charging device for an alkaline battery according to any one of claims 1 to 5, wherein the nickel-hydrogen battery is cooled according to a temperature detected by the first temperature sensor.