JPH09219279A - Control method for battery heating device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep a battery at a fixed temperature or higher with extremely small power consumption when the batty is heated in order to prevent electric capacity decrease resulting from the temperature fall of the battery in an extremely cold district. SOLUTION: A thermal element is closely fitted on the outer periphery of a battery B so as to generate a voltage in proportion to the temperature of the battery B. A heating control circuit for the battery B is installed so that when the voltage reaches a specific voltage the same shuts off or applies power fed to a PTC heating body PTC, which is likewise closely fitted to the outer periphery of the battery B for heating the battery B, so as to keep the temperature of battery solution at a fixed temperature or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of controlling a battery heating device which prevents the battery from deteriorating in cold regions.

[0002] In cold regions, for example, when the battery fluid of a battery mounted on an automobile reaches about -10 ° C, the electric capacity of the battery decreases and it becomes unusable. Conventionally,
As a measure to prevent this decrease in capacity, a method of coating the outer surface of the battery with a heat insulating heat insulating material such as urethane or a method of increasing the battery capacity (for example, in the case of a 2000 cc class car, a battery of 50 A is usually used. However, a 60A battery is used for cold climates).

[0003]

However, these measures are not drastic measures for the battery capacity reduction prevention method, and therefore, in extreme cold regions where the temperature is -20 ° C or -30 ° C, for example. The measures are not very useful. Therefore, in such a case, it is considered that the battery is actively heated to prevent the temperature of the battery liquid from decreasing.

As this method, generally, a resistance heating wire such as Ni-Cr or Fe-Ni-Cr or a heating resistor such as an alloy film thereof is energized to prevent the temperature from being lowered due to the generated heat. Conceivable. However, in this case, there is a drawback that the power consumption becomes extremely large unless there is any control means for the temperature. In the case of an automobile battery, the electric power of the battery must be used for heating the battery, so the electric power for heating must be suppressed as much as possible.

The present inventors have previously filed a patent application in order to achieve the above object. (Filing date: Jan. 5, 1996, reference number P9601-071) This is a battery using a planar heating element in which a ceramic PTC heating element is attached to a heat dissipation plate made of metal, ceramics, resin or the like having good thermal conductivity. It was something to heat. Also, subsequently applied for a patent. (Filing date: February 2, 1996, reference number P9602-072) This is for heating a battery using a planar heating element in which a resin-based PTC heating element paste is applied to a flexible substrate.

When a constant voltage is applied to the PTC heating element, a current flows according to the initial resistance and the temperature rises due to self-heating, but when the Curie temperature is reached, the resistance rapidly increases and the current also sharply decreases. Hold. Therefore, when the PTC heating element as described above is used, it has a self-control function, so that the power consumption decreases as the outside air temperature rises. Therefore, the power consumption of the battery can be reduced as compared with a resistance heating element such as Ni-Cr or Fe-Ni-Cr.

However, in the patent application of the previous application, the Curie temperature generally used for both the ceramic PTC heating element and the resin-based PTC heating element is about 40 to 200 ° C. It is not impossible to manufacture a PTC heating element having a Curie temperature of 40 ° C. or less, but it is technically difficult and the manufacturing cost becomes very high. Therefore, if you want to keep the liquid temperature of the battery at 0 ± 10 ° C, for example, if you use a PTC heating element with a Curie temperature of 40 ° C, it will be 0 ± 10 ° C and 40 ° C.
The power consumption of the battery is wasted by the amount corresponding to the temperature difference between the temperature and the temperature. An object of the present invention is to reduce this waste and further reduce power consumption. Therefore, the present invention relates to improvements of the two inventions of the previous application.

[0008]

SUMMARY OF THE INVENTION According to the present invention, a control circuit including a heat generating element using a battery as a power source and a heat sensitive element is installed on the outer periphery of a battery, and a voltage change generated in the heat sensitive element is sensed. A method for controlling a battery heating device for controlling the supply current of the heating element. The heating element of the present invention is a ceramic PTC heating element or a resin-based flexible PTC.
It is a heating element, and the heat-sensitive element is an NTC thermistor or P
It is a TC thermistor.

According to the present invention, the temperature of the battery determines the internal resistance of the temperature sensitive element contacting the battery, and the current flowing through the heat sensitive element changes in accordance with the temperature change of the battery. The change is taken out, and when the voltage across the heat sensitive element falls below (or rises above) the specified voltage, the current flowing through the heating element is stopped. When the voltage across the heat-sensitive element rises (or falls) above the specified voltage, current is supplied again to the heating element to heat the battery. By repeating these steps, the liquid temperature of the battery can be maintained at a constant temperature.

In the present invention, the heat-sensitive element is attached in close contact with a heat radiating plate having a ceramic PTC heating element adhered to the outer periphery of the battery or a flexible substrate coated with a resin PTC heating element. Further, the entire control circuit including the battery, the heating element and the heat sensitive element is surrounded by an appropriate heat insulation material.

As shown in FIG. 1, the control circuit of the battery heating device has a thermosensitive element and a fixed resistor connected in series, and if the voltage of the battery is applied from both ends, the voltage generated in the thermosensitive element is It changes depending on the temperature of the heat sink or flexible board that is in close contact with the battery.

The voltage generated in the heat sensitive element is taken out and used as one input of the voltage comparator. The other input of the voltage comparator receives the specified voltage divided from the battery. The output of the voltage comparator is connected to the base of the output transistor through a protection resistor, one end of the heating element serving as a load is connected to the emitter or collector of the output transistor, and the other end is connected to the negative or positive electrode of the battery. . The output transistor may be either NPN type or PNP type.

[0013]

EXAMPLE A control circuit for a battery heating apparatus according to the present invention as shown in FIG. 1 was prepared. Ceramic P for the heating element
A TC heating element was used and an NTC thermistor was used for the heat sensitive element. Further, the Curie temperature of the ceramic PTC heating element was set to 37 ° C., and a 12 V battery was used as a power source.

In FIG. 1, R1 = R2 = R3 = 15K
Ω, R4 = R5 = 100KΩ, R6 = 1KΩ, NT
A C thermistor having a resistance at 25 ° C. of 10 KΩ (B constant of 3170 ° K) and a ceramic PTC heating element having a resistance at 25 ° C. of 24 Ω were used.

FIG. 2 shows the relationship between the outside air temperature and the average power consumption of the battery required to heat the battery. The dotted line (C1) shows the case of only the ceramic PTC heating element of the previous application, and the solid line (C2) shows the case of using the control method according to the present invention and the ceramic PTC heating element. As is apparent from FIG. 2, according to the present invention, the power consumption can be significantly reduced as compared with the case of the previous application.

FIG. 3 shows the relationship between the battery liquid temperature of the battery and the outside air temperature when the control method according to the present invention is used.

In this embodiment, the ceramic PTC heating element is used as the heating element, but it is not limited to this, and it goes without saying that a resin PTC heating element may be used.

[0018]

EFFECTS OF THE INVENTION According to the present invention, since the control method using the PTC heating element and the temperature sensitive element as described above, the outside air temperature is in the range of −30 to 15 ° C. as compared with the battery heating device of the previous application. Even if compared, it is possible to save 15-85% of power consumption, and even in extremely cold regions, a battery heating device that keeps the battery liquid temperature above a certain temperature with extremely low power consumption and prevents the battery's electric capacity from decreasing. Can be provided.

[Brief description of drawings]

FIG. 1 is an example of a circuit diagram used in a method for controlling a battery heating device according to the present invention.

FIG. 2 is a diagram showing an outside air temperature and an average power consumption of the battery required for heating the battery.

FIG. 3 is a diagram showing the relationship between the battery liquid temperature and the outside air temperature of the battery when the control method according to the present invention is used.

[Explanation of symbols]

 R1, R2, R3, R4, R5, R6 Fixed resistance TH NTC thermistor A Voltage comparator Q Output transistor PTC PTC Heating element B Battery

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[Procedure amendment]

[Submission date] April 12, 1996

[Procedure amendment 1]

[Document name to be amended] Statement

[Name of item to be corrected] 0002

[Correction method] Added

[Correction contents]

[0002]

2. Description of the Related Art In cold regions, for example, when the battery fluid of a battery mounted on an automobile reaches about -10 ° C., the electric capacity of the battery decreases and it becomes unusable. Conventionally, as a measure for preventing the deterioration of the capacity, a method of coating the outer surface of the battery with a heat insulating material such as urethane or a method of increasing the battery capacity (for example, displacement 2000c
In the case of a c-class automobile, a battery of 50 A is usually used, but a battery of 60 A is used for cold climates).

Claims (2)

[Claims] 1. A control circuit including a heat-generating element and a heat-sensitive element, which are powered by the battery, is installed on the outer periphery of the battery,
A method for controlling a battery heating device, comprising controlling a supply current of the heating element by sensing a voltage change generated in the heat sensitive element. 2. The heating element is a ceramic PTC heating element or a resin flexible PTC heating element, and the heat-sensitive element is N
The method for controlling a battery heating device according to claim 1, wherein the method is a TC thermistor or a PTC thermistor.