JP2022152834A - Charge control device - Google Patents

Abstract

To provide a charge control device which can prevent deterioration of a battery in charge state determination.SOLUTION: A charge state determination unit of an ECU applies generated voltage set by a generated voltage setting unit on the basis of battery temperature to a battery and determines a charge state of the battery on the basis of charge current of the battery in application of the generated voltage (a step S4) when a discharge integrated amount is high (YES in a step S3) in initial startup after soak (YES in a step S2). The generated voltage setting unit sets the generated voltage to voltage lower than in the case that the battery temperature is intermediate temperature when the battery temperature is higher than the predetermined intermediate temperature. The generated voltage setting unit sets the generated voltage to voltage higher than in the case that the battery temperature is the intermediate temperature when the battery temperature is lower than the predetermined intermediate temperature.SELECTED DRAWING: Figure 2

Description

The present invention relates to a charging control device.

In Patent Document 1, when an ignition-on signal is input, the charge control unit charges the battery for a predetermined determination time Tr, so that the state of charge determination unit determines the state of charge SOC of the battery immediately after the engine starts. A technique for calibrating the recognized state of charge SOCr by the state of charge recognizer is described. In the technique described in Patent Document 1, the charging voltage to the battery when determining the state of charge SOC is set to 14.5V.

International Publication No. 2016/072091

However, in the technique described in Patent Document 1, the charging voltage of the battery when determining the state of charge SOC is always set to a constant voltage, so the battery is degraded when determining the state of charge SOC. There was a risk that I would lose it.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a charging control apparatus capable of preventing deterioration of a battery when determining the state of charge.

The present invention is a charging control device for controlling charging from a generator to a battery, comprising a power generation control unit for controlling the generator to generate power at a set power generation voltage, and detecting a charging current to the battery. a charging current detection unit that determines the charging state of the battery based on the charging current detected by the charging current detection unit; a temperature detection unit that detects the temperature of the battery as a battery temperature; a power generation voltage setting unit that sets the power generation voltage of the generator based on the battery temperature, and the state of charge determination unit determines the power generation voltage set by the power generation voltage setting unit based on the battery temperature. The charging state is determined based on the charging current of the battery when the generated voltage is applied.

As described above, according to the present invention, it is possible to provide a charging control device capable of preventing deterioration of the battery when determining the state of charge.

FIG. 1 is a configuration diagram of a vehicle equipped with a charging control device according to an embodiment of the invention. FIG. 2 is a flow chart for explaining the state-of-charge determination operation of the charging control device according to the embodiment of the present invention. FIG. 3 is a generated voltage setting map that defines the relationship between the battery temperature and the generated voltage, which is referred to by the charging control device according to the embodiment of the present invention during the charge state determination operation.

A charging control device according to an embodiment of the present invention is a charging control device that controls charging from a generator to a battery, and includes a power generation control unit that controls the generator to generate power at a set power generation voltage. a charging current detection unit for detecting the charging current to the battery; a charging state determination unit for determining the charging state of the battery based on the charging current detected by the charging current detection unit; and detecting the temperature of the battery as the battery temperature. a temperature detection unit; and a power generation voltage setting unit that sets the power generation voltage of the generator based on the battery temperature. and the state of charge is determined based on the charging current of the battery when the generated voltage is applied. As a result, the charging control device according to the embodiment of the present invention can prevent deterioration of the battery when determining the state of charge.

An embodiment of the present invention will be described in detail below with reference to the drawings. In FIG. 1, a vehicle 1 equipped with a charging control device according to an embodiment of the present invention includes an alternator 3 as a generator, a battery 5 capable of charging the power generated by the alternator 3, and a charging control device. It is configured including an ECU (Electronic Control Unit) 10 .

The vehicle 1 includes an internal combustion engine (not shown) mechanically connected to an alternator 3 , and power generated by the engine is transmitted to the alternator 3 . An engine performs, for example, a series of four strokes consisting of an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke while the piston makes two reciprocations in the cylinder, and ignites between the compression stroke and the expansion stroke. made up of an engine.

The alternator 3 generates electricity by rotating with the driving force transmitted from the engine. The alternator 3 generates a voltage according to the generated voltage command value from the ECU 10 .

The battery 5 is a lead-acid battery with a rated voltage of 12 [V], stores electricity generated by the alternator 3 , and supplies the stored electricity to the electrical load 6 . The battery 5 has two electrodes using lead and a battery liquid (electrolyte).

The battery 5, which is a lead-acid battery, is easily affected by the ambient temperature, and has the characteristic of being deteriorated and having a short life especially at high temperatures. The battery 5 is not limited to a lead-acid battery, and may be a secondary battery such as a nickel-metal hydride battery or a lithium-ion battery. All types of secondary batteries have the characteristic of progressing deterioration at high temperatures.

A current sensor 17 is provided in the battery 5 , and the current sensor 17 detects current flowing in and out of the battery 5 and outputs the detected current to the ECU 10 . The current detected by the current sensor 17 is the current supplied from the battery 5 to the electric load 6 and the current charged from the alternator 3 to the battery 5 .

A temperature sensor 18 is provided in the battery 5 , and the temperature sensor 18 detects the temperature of the battery 5 and outputs it to the ECU 10 . The temperature detected by the temperature sensor 18 is the liquid temperature of the battery liquid in the battery 5 .

The ECU 10 controls the engine and the alternator 3 . The ECU 10 is composed of a computer unit including a CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), flash memory, an input port, an output port, and a network module. ing.

The network module can communicate with other ECUs (not shown) via a network such as CAN (Controller Area Network) or Flexray.

The ROM of the ECU 10 stores a program for causing the computer unit to function as the ECU 10 along with various control constants, various maps, and the like. That is, the computer unit functions as the ECU 10 when the CPU of the ECU 10 executes a program stored in the ROM.

In this embodiment, a current sensor 17 and a temperature sensor 18 are connected to the input port of the ECU 10 . On the other hand, the alternator 3 is connected to the output port of the ECU 10 . The ECU 10 controls the voltage generated by the alternator 3 based on the detection signals of the current sensor 17 and the temperature sensor 18, and controls the charging of the battery 5 from the alternator 3.

The ECU 10 includes a power generation control section 10A, a charging current detection section 10B, and a state of charge determination section 10C. The power generation control unit 10A controls the alternator 3 to generate power at the set power generation voltage (power generation voltage command value). A charging current detector 10B detects a charging current to the battery 5 . The charging current detector 10B detects the charging current by means of a current sensor 17. FIG. The charging state determination unit 10C determines the state of charge (SOC) of the battery 5 based on the charging current detected by the charging current detection unit 10B.

In this embodiment, the ECU 10 includes a temperature detection section 10D that detects the temperature of the battery liquid (liquid temperature) of the battery 5 as the battery temperature.

Further, the ECU 10 includes a power generation voltage setting section 10E, and the power generation voltage setting section 10E sets the power generation voltage of the alternator 3 based on the battery temperature. Here, the voltage generated by the alternator 3 is equal to the charging voltage of the battery 5 . Therefore, the generated voltage setting unit 10E sets the charging voltage of the battery 5 based on the battery temperature.

The generated voltage setting unit 10E refers to the generated voltage setting map shown in FIG. 3 to set the generated voltage of the alternator 3 when determining the state of charge of the battery 5. FIG. In the generated voltage setting map, the vertical axis indicates the state of charge, and the horizontal axis indicates the battery temperature. The power generation voltage setting map is divided into an appropriate power generation voltage region, an insufficient charge region, and a thermal runaway region.

The proper generated voltage region is a region of proper generated voltage according to the battery temperature. In the appropriate generated voltage region, a set generated voltage, which is an optimum generated voltage corresponding to the battery temperature, is set for each battery temperature. The undercharged region is a region where charging is insufficient because the voltage is lower than the appropriate charging voltage. The thermal runaway region is the region where the battery temperature becomes too high due to higher than proper charging voltage. The generated voltage setting unit 10E controls the alternator 3 based on the battery temperature so that the generated voltage becomes the set generated voltage.

Then, the state-of-charge determining unit 10C applies the generated voltage set by the generated voltage setting unit 10E to the battery 5 based on the battery temperature, and charges the battery 5 based on the charging current of the battery 5 when the generated voltage is applied. determine the state.

In the generated voltage setting map of FIG. 3, the temperature on the horizontal axis is divided into a predetermined intermediate temperature region, a region higher than the intermediate temperature, and a region lower than the intermediate temperature.

When the battery temperature is higher than a predetermined intermediate temperature, the generated voltage setting unit 10E sets the generated voltage to a lower voltage than when the battery temperature is the intermediate temperature. Further, when the battery temperature is lower than the predetermined intermediate temperature, the generated voltage setting unit 10E sets the generated voltage to a higher voltage than when the battery temperature is the intermediate temperature.

In setting the voltage generated by the alternator 3 when determining the state of charge of the battery 5, the generated voltage setting unit 10E does not perform correction in consideration of the degree of deterioration of the battery 5 or the like.

The charging state determination operation of the charging control device according to the present embodiment configured as described above will be described. This state-of-charge determination operation is repeatedly executed at a predetermined short period during system activation.

The ECU 10 acquires vehicle/parts information in step S1. In this step S1, the ECU 10 acquires detection signals from various sensors of the vehicle 1 and confirms whether or not there is an abnormality in order to protect the parts and stabilize the power supply.

Next, in step S2, the ECU 10 determines whether or not the engine is being started for the first time after soaking. In this step S2, the ECU 10 determines whether or not it is the first time the system is started by turning on the ignition key after the ignition key (not shown) is turned off and the vehicle is parked (soaked). In the case of NO, the current operation is terminated.

Next, when the determination in step S2 is YES, the ECU 10 determines in step S3 whether or not the integrated discharge amount is high. In this step S3, the ECU 10 acquires the integrated amount of discharge current of the battery 5, and determines that the integrated discharge amount is high if this value is equal to or greater than the threshold value. If the determination in step S2 is NO, the ECU 10 ends the current operation.

If the determination in step S3 is YES, the ECU 10 determines the battery charging current in step S4. In this step S4, the state-of-charge determining unit 10C of the ECU 10 applies the generated voltage set by the generated voltage setting unit 10E based on the battery temperature to the battery 5, to determine the state of charge of the battery 5.

Next, in step S5, the ECU 10 determines whether or not to detect a deviation in the integrated amount of discharge. In this step S5, the ECU 10 determines whether it is necessary to detect and calibrate the deviation of the integrated discharge amount based on the integrated discharge amount acquired in step S3 and the battery charging current determined in step S4. . If the determination is NO, the ECU 10 terminates the current operation.

If it is determined in step S5 that the deviation of the integrated discharge amount is detected, the deviation is detected and the integrated discharge amount is calibrated. Thereafter, in step S6, the ECU 10 shifts to the optimum charging/discharging operation after calibrating the integrated discharge amount.

As described above, in this embodiment, the state of charge of the battery 5 is determined at the first start after the soak when the battery 5 is not charged or discharged by other control. Also, the voltage applied to the battery 5 when determining the state of charge is set according to the battery temperature.

As described above, the charging control device of this embodiment includes the power generation control section 10A that controls the alternator 3 so as to generate power at the set power generation voltage, and the charging current detection section 10B that detects the charging current to the battery 5. , and a state-of-charge determination unit 10C that determines the state of charge of the battery 5 based on the charge current detected by the charge-current detection unit 10B. Further, the charging control device of this embodiment includes a temperature detection section 10D that detects the temperature of the battery 5 as the battery temperature, and a power generation voltage setting section 10E that sets the power generation voltage of the alternator 3 based on the battery temperature. there is Then, the state-of-charge determining unit 10C applies the generated voltage set by the generated voltage setting unit 10E based on the battery temperature to the battery 5, and determines the state of charge based on the charging current of the battery 5 when the generated voltage is applied. do.

As a result, when determining the state of charge of the battery 5 , the generated voltage set based on the battery temperature is applied from the alternator 3 to the battery 5 . As a result, it is possible to prevent deterioration of the battery 5 when determining the state of charge.

Further, in the charging control device of the present embodiment, when the battery temperature is higher than the predetermined intermediate temperature, the generated voltage setting unit 10E sets the generated voltage to a lower voltage than when the battery temperature is at the intermediate temperature. set.

As a result, when the battery temperature is high and the battery is charged at a high voltage, it is possible to prevent reduction due to vaporization of the battery liquid, thereby preventing deterioration of the battery.

In addition, in the charging control device of this embodiment, when the battery temperature is lower than the predetermined intermediate temperature, the generated voltage setting unit 10E sets the generated voltage to a higher voltage than when the battery temperature is at the intermediate temperature. set.

This prevents the battery 5 from being undercharged when charging at a low voltage when the battery temperature is low, and prevents the battery 5 from over-discharging due to insufficient charging (battery exhaustion) and deterioration of the battery 5 due to over-discharging. can.

Although embodiments of the present invention have been disclosed, it will be apparent that modifications may be made by those skilled in the art without departing from the scope of the invention. All such modifications and equivalents are intended to be included in the following claims.

3 Alternator (generator)
5 Battery 10 ECU (charging control device)
10A power generation control unit 10B charging current detection unit 10C charging state determination unit 10D temperature detection unit 10E power generation voltage setting unit

Claims (3)

A charging control device for controlling charging from a generator to a battery,
a power generation control unit that controls the generator to generate power at the set power generation voltage;
a charging current detection unit that detects a charging current to the battery;
a state of charge determination unit that determines the state of charge of the battery based on the charge current detected by the charge current detection unit;
a temperature detection unit that detects the temperature of the battery as a battery temperature;
a power generation voltage setting unit that sets the power generation voltage of the generator based on the battery temperature,
The state-of-charge determining unit applies a generated voltage set by the generated voltage setting unit to the battery based on the battery temperature, and determines the state of charge based on the charging current of the battery when the generated voltage is applied. A charging control device characterized by determining: When the battery temperature is higher than a predetermined intermediate temperature, the generated voltage setting unit sets the generated voltage to a lower voltage than when the battery temperature is the intermediate temperature. The charging control device according to claim 1. When the battery temperature is lower than a predetermined intermediate temperature, the generated voltage setting unit sets the generated voltage to a higher voltage than when the battery temperature is the intermediate temperature. The charging control device according to claim 1.

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