KR20080040500A - Apparatus for charge control and method of thereof - Google Patents

Abstract

An apparatus and a method for charge control are provided to prevent damage of a secondary battery due to a temperature rise by determining charge continuance by calculating a charged amount again after judging a charge finish due to a temperature. An apparatus for charge control includes a charge unit, sensor units(152,153), a control unit(150), and a discharge unit(160). The charge unit receives power from a power supply unit and supplies the power to a charging secondary battery(130). The sensor units measure a voltage and a temperature of the secondary battery charged by the charge unit. The control unit controls charge and discharge of the secondary battery by judging a charge state of the secondary battery through the measured values from the sensor unit. The discharge unit supplies power discharged from the secondary battery to a load(160) by control of the control unit.

Description

Charge control device and method thereof

1 is a block diagram schematically showing a conventional renewable energy generation system.

2 is a charging pattern graph of a storage battery (secondary battery) for renewable energy power storage.

Figure 3 is a block diagram showing a renewable energy generation system equipped with a charge control device according to an embodiment of the present invention.

Figure 4 is a block diagram showing a charging control device according to another embodiment of the present invention.

5 is a block diagram showing a charging control device according to another preferred embodiment of the present invention.

6 is a graph of the charging end voltage correlation for each temperature of a secondary battery for renewable energy power storage.

7 is a schematic view showing a display unit used in the charging control device according to another preferred embodiment of the present invention.

8 is a flow chart showing the operation sequence of the charging control device according to an embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

10, 110 ... Renewable energy 20 ... Charge

30, 130 ... rechargeable battery 40 ... discharge

120 charging / discharging section 150 control section

151 ... current sensor 152 ... voltage sensor

153 Temperature sensor 160 ... Load

180 ... display

The present invention relates to a charging control device and a method thereof, and more particularly, to a device and a method for controlling the charging of a secondary battery having a renewable energy as a power supply, a small change in voltage according to the state of charge will be.

Renewable energy is an abbreviation of 'new energy and renewable energy' and does not use existing fossil fuels such as coal (petroleum coal, anthracite coal), heavy oil, and liquefied natural gas (LNG) as energy, and is environmentally friendly. Refers to the production of energy using landfill gas and the like.

In order to effectively use such renewable energy, a secondary battery (mainly a storage battery, hereinafter referred to as a secondary battery) capable of storing the generated energy is essentially required.

1 is a block diagram schematically showing a conventional renewable energy generation system.

Referring to FIG. 1, a renewable unit 10, such as solar, wind, and fuel cells, and a charging unit for charging the secondary battery 30 with power generated and supplied by the renewable energy 10 ( 20), a secondary battery 30 which is charged by the charging unit, a discharge unit 40 for supplying electric power charged in the secondary battery 30 to the load 60, and the charging unit 20 and the room It can be seen that the control unit 50 and the load 60 for controlling the whole 40.

As the secondary battery 30, a lead acid battery is generally used. The lead material of the lead-acid battery is lead (Pb) is increasingly limited as a heavy metal harmful to the human body, accordingly, the situation is being replaced by environmentally friendly products centered on government agencies and local governments in Korea. Currently, the lead-acid battery replaces the lead-acid battery in an environmentally friendly manner.

Ni-MH rechargeable batteries meet the needs of users in terms of changes, prices, and performances that are subject to high oil prices and environmental protection regulations throughout the industry. Currently, the field of application is expanding throughout the industry, such as solar power storage, wind power storage, hybrid fuel cell system, hybrid vehicle, military use.

However, in using such a nickel-hydrogen secondary battery, a problem arises in using the conventional renewable energy generation system and the charging control device for lead-acid batteries therein.

As shown in FIG. 2, the lead-acid battery has a large voltage fluctuation range according to the state of charge. Therefore, the conventional charging control device uses a method of measuring only the voltage of the lead-acid battery to determine the degree of charging.

However, in a battery having a small voltage fluctuation range depending on a state of charge, such as a nickel-hydrogen secondary battery, it is difficult to determine the degree of charge in the same manner as in the prior art, and thus the charge control is not properly performed.

As a result, in the case of the nickel-hydrogen secondary battery using the conventional charging control device, the charging and discharging are not performed smoothly, and thus, the life due to the memory effect, the electrolytic nucleus leakage due to the overcharging, and the like, the output capacity decreases. The situation is facing a variety of problems, such as damage to the load.

The present invention has been made to improve the above-mentioned problems, and the charge control device capable of smoothly charging and discharging the secondary battery by effectively calculating the state of charge of the secondary battery having a small voltage fluctuation range according to the state of charge and its It is an object to provide a method.

In order to achieve the above object, the present invention provides a renewable energy source such as solar, wind, fuel cells as a power source, the apparatus for controlling the charging of the secondary battery with a small change in voltage according to the state of charge, the power A charging unit for supplying electric power from a source to the secondary battery to be charged; A sensor unit measuring a voltage and a temperature of the secondary battery charged by the charging unit; A controller which determines the state of charge of the secondary battery using the value measured by the sensor unit and controls the charge / discharge of the secondary battery using the measured state; And a discharge unit supplying power to the load discharged from the secondary battery under control of the controller.

Here, it is preferable that the charging unit and the discharge unit also function as their functions.

In addition, the secondary battery is preferably a sealed nickel-hydrogen secondary battery.

The display unit may further include a display unit which displays the state of charge of the secondary battery determined by the controller to the outside through a wired / wireless network. When the display unit is a wireless network, the display unit is a mobile communication terminal. Do.

The determination of the state of charge of the secondary battery made by the control unit may include: a charge end voltage value for each temperature previously examined and stored in a memory; It is preferable to perform the measurement by comparing the measured voltage and temperature values on the secondary plane.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

3 is a block diagram showing a renewable energy generation system equipped with a charging control device according to an embodiment of the present invention.

Referring to FIG. 3, the charging control device according to the present embodiment includes a charging unit configured to supply power from the renewable energy 110 to the secondary battery 130 to be charged; Sensor units 152 and 153 for measuring the voltage and temperature of the secondary battery 130 charged by the charging unit; A controller 150 that determines the state of charge of the secondary battery 130 by using the values measured by the sensor units 152 and 153, and controls charging and discharging of the secondary battery 130 using the measured state; It can be seen that the control unit 150 is composed of a discharge unit for supplying power to the load 160 discharged from the secondary battery 130.

The charging unit is interposed between a power supply such as renewable energy and the secondary battery 130, and is provided with circuits such as charge switching and battery protection. Meanwhile, the discharge part performs the same role as the charging part between the secondary battery 130 and the load 160, but may be disposed separately from the charging part. It consisted of the discharge part 120. In order to use both the charging unit and the discharging unit as described above, the controller 150 must grasp the state in which the charging is completed (the end of charging). Otherwise, the charging unit and the discharge unit are charged and discharged through the charging / discharging unit composed of one element (combination). The discharges are mixed to cause problems such as deterioration of the life of the secondary battery and memory effect.

The sensor units 152 and 153 measure the state of charge of the secondary battery 130. In this embodiment, the sensor unit 152 and 153 includes a voltage sensor 152 and a temperature sensor 153. Unlike the conventional lead acid battery, the secondary battery of the present embodiment is intended to be a secondary battery having the same characteristics as a sealed nickel-hydrogen secondary battery having a small change in voltage depending on the state of charge. It is not easy to grasp. Therefore, a separate temperature sensor is provided to grasp the state of completion of charging (end of charge) and the timing.

As such, the termination of the charge is determined by the controller 150 receiving the values measured by the sensor units 152 and 153.

The controller 150 compares the value measured by the sensor unit with a previously stored reference value to determine the state of charge. In the present embodiment, the controller 150 determines the state of charge by using the temperature and the voltage value.

Of course, when the surrounding temperature can be kept constant, it is possible to discriminate only by the temperature (in this case, the sensor unit can be configured only by the temperature sensor). That is, after storing the temperature value at the end of charge state as a reference value, if the temperature increased after charging exceeds the reference temperature value, it is determined as the end of charge, and ends the charging switching role of the charging unit or the charging / discharging unit. . That is, the charging current is adjusted to zero.

In addition, the reference value may be determined by quantifying the relationship between the temperature according to the capacity of the secondary battery and the charging end voltage as shown in FIG. 6 (correlation table between the charging end voltage and temperature).

The temperature may vary depending on the operating conditions, but it is preferable to set the temperature within the range of 45 to 55 ° C., and the temperature sensor and voltage after storing the voltage (end voltage) at the end of charging for each temperature in the memory of the controller. If the measured (temperature, voltage) point measured by the sensor exists on the upper right side of the diagonal line of FIG. 6, the end of charging is determined by the end of charging. do. That is, the charging end voltage value for each temperature stored in the memory; The end state of charging is determined by comparing the measured voltage and temperature values on the second plane.

As such, the end point of charging can be accurately determined by the control unit. Thus, even when the charging unit and the discharge unit are used together as in the charging / discharging unit 120, the secondary battery can be operated as a charging unit until the charging end point and as a discharge unit after the charging end point. The battery can be used efficiently.

4 is a block diagram showing a charging control device according to another embodiment of the present invention.

Referring to FIG. 4, the charging control device according to the present embodiment further includes a display unit 180 connected to the control unit 150 to display the charging state of the secondary battery 130 to the outside through a wired / wireless network. You can see that.

The display unit 180 displays a state of charge of the secondary battery to a monitor or a user who is separated from the charging control device. The display unit 180 uses a short-range or medium-range wireless communication using a wired communication such as a cable or an RF communication as a means. Long distance wireless communication method is applicable.

Through this, the user can accurately grasp the state of charge of the secondary battery from the outside, and at this time, the matter displayed to the user through the display unit 180 is the charge amount to display the charge level as a percentage (%) as shown in FIG. , Voltage (V), temperature (° C.), and the like. Of course, voice output through speakers and earphones is also possible.

5 is a block diagram illustrating a charging control device according to another embodiment of the present invention. Referring to FIG. 5, a current sensor 151 for measuring a current value of the secondary battery 130 is further provided in the sensor unit. Able to know.

By providing the current sensor 151, the control unit of the charging control device according to the present embodiment is to collect the current, voltage, temperature as a measurement value for the determination of the end of the charge, the exact amount of charge ( SOC) can be calculated.

CO: nickel-hydrogen secondary battery capacity

Cs: self discharge amount (Ah)

Ca: decrease over time (Ah)

Td: Secondary battery end temperature (° C) during discharge

Tc: Secondary battery end temperature (° C) during charging

Δt: Sampling time (sec)

id (t): secondary battery discharge current (A)

ic (t): secondary battery charging current (A)

Kd (Td, id (t)): secondary battery discharge efficiency at Td, id (t)

Kc (Tc, ic (t)): Secondary battery charging efficiency at Tc, ic (t)

Values related to the characteristics of the secondary battery among the above values should be investigated or measured in advance, but more accurate determination of the charge end voltage using only the temperature or the determination of the charge end voltage using the correlation table between the charge end voltage and the temperature is possible. .

As described above, the present invention uses a renewable energy such as solar, wind, fuel cells, etc. as a power source, in order to control the charging of the secondary battery with a small change in voltage according to the state of charge, the end of charge state temperature Discrimination is carried out using only bays, or using temperature and voltage, or using and discriminating temperature, voltage and current.

The determination method using the temperature, the voltage and the current can be determined only by the charge amount, but can be determined using all or two or only three determination methods described above according to the purpose and the surrounding environment. Will be described with reference to FIG. 8.

First, when charging is performed, the sensor unit 151, 152, and 153 measures current, voltage, and temperature in the secondary battery 130 (S 210), and the controller 150 measures the measured temperature. Value is compared with the reference temperature value (preferably set within the range of 45 ~ 55 ℃ according to the operating conditions) .If the measured temperature is higher than the reference temperature, it is determined that the charging is completed. Adjust to (S 290) (S 220).

When the measured temperature is lower than the reference temperature, the charging amount (%) is calculated using Equation 1 using not only the measured temperature but also the measured current and voltage (S 230).

If the calculated charge amount is 100% or more, the charging current is adjusted to 0 while the charging is completed (S290), and if less than 100%, charging is continued (S240). As described above, the determination of whether the charge is continued by recalculating the charge amount after determining the end of charge by temperature is for preventing the damage of the secondary battery due to the temperature increase of the secondary battery.

When the end of charge is determined only by temperature, the end of charge may not be accurately determined due to the influence of the surrounding environment. Therefore, there may be a case where charging is not 100% even when the temperature is higher than the end of charge. However, even in such a case, in order to prevent damage to the secondary battery due to the increase in temperature, charging is first terminated when the temperature is higher than the reference temperature. After that, recharging the charge amount is completed even when the charging temperature is lower than the reference temperature. Because there are cases.

When it is determined that the charge amount is less than 100%, the charging voltage is set by comparing the voltage control value according to the temperature using the correlation table between the charging end voltage and the temperature of FIG. 6 (S 250), and the set voltage value. The amount of current to be charged to perform the charging is controlled by (the charge end voltage value at the current temperature) (S260).

Here, the configuration of the charge control device using the voltage and the temperature is used to control the amount of current so that charging is performed at the charging end voltage corresponding to the current temperature.

On the other hand, the measurement or calculation results in the S 210, S 230 to determine the state of charge of the secondary battery is displayed to the user through the display unit (S 270), if necessary to make a data stored (S 280).

Although the above example is given as an operation method of the charging control device according to the present invention, the configuration includes the steps of measuring the voltage and temperature of the secondary battery charged by the power supply; Transmitting the measured value to a memory; Comparing the transmitted measured value with a pre-stored reference value; Since it is based on the step of determining whether to continue the charging based on the result of the comparison, all the way to take such operation corresponds to the operation method of the charging control device according to the present invention.

For reference, the reference value may be a charging end voltage value according to temperature, but in the above embodiment, the charging end voltage value is used as a set voltage value rather than a reference value.

As described above, the charging control device and the method according to the present invention is a renewable energy source such as solar, wind power, fuel cell, etc. as a power supply, in the secondary battery having a small voltage fluctuation range according to the state of charge, By efficiently calculating the state of charge of the secondary battery and efficiently managing the charge, it is possible to smoothly charge and discharge the secondary battery and prevent damage.

Claims (16)

In the device for controlling the charging of the secondary battery, the renewable energy such as solar, wind, fuel cells, etc. as a power source, the voltage change according to the state of charge is small, A charging unit for supplying electric power from the power supply to the secondary battery to be charged; A sensor unit measuring a voltage and a temperature of the secondary battery charged by the charging unit; A control unit for determining the state of charge of the secondary battery using the value measured by the sensor unit, and controlling the charge / discharge of the secondary battery using the same; A discharge unit supplying power to the load discharged from the secondary battery under control of the controller; Charging control device comprising a. The method of claim 1, The charging control unit and the discharge unit is characterized in that the charge control device. The method of claim 1, The secondary battery is a charge control device, characterized in that the sealed nickel-hydrogen secondary battery. The method of claim 1, And a display unit which displays the state of charge of the secondary battery determined by the controller to the outside through a wired / wireless network. The method of claim 4, wherein The display control unit is characterized in that the mobile communication terminal. The method of claim 1, Determination of the state of charge of the secondary battery made by the control unit is the charge end voltage value for each temperature that has been previously investigated and stored in the memory; Charge control device, characterized in that performed by comparing the measured voltage, temperature value on the secondary plane. The method of claim 1, The sensor unit charge control device, characterized in that for further measuring the current of the secondary battery. The method of claim 7, wherein Determination of the state of charge of the secondary battery made by the controller is a formula for obtaining the charge amount (SOC) of the secondary battery

CO: nickel-hydrogen secondary battery capacity Cs: self discharge amount (Ah) Ca: decrease over time (Ah) Td: Secondary battery end temperature (° C) during discharge Tc: Secondary battery end temperature (° C) during charging Δt: Sampling time (sec) id (t): secondary battery discharge current (A) ic (t): secondary battery charging current (A) Kd (Td, id (t)): secondary battery discharge efficiency at Td, id (t) Kc (Tc, ic (t)): Secondary battery charging efficiency at Tc, ic (t) Charge control device, characterized in that carried out by. In the method of controlling the charging of the secondary battery, the renewable energy such as solar, wind, fuel cells, etc. as a power source, the voltage change according to the state of charge is small, Measuring a voltage and a temperature of the secondary battery charged by the power supply; Transmitting the measured value to a memory; Comparing the transmitted measured value with a pre-stored reference value; Determining whether the charging is continued based on the comparison result Charging control method comprising a. The method of claim 9, The secondary battery is a charge control method, characterized in that the sealed nickel-hydrogen secondary battery. The method of claim 9, The reference value is a charging control method, characterized in that the charging end voltage value according to the temperature. The method of claim 9, The measuring step is a charge control method, characterized in that for further measuring the current. The method of claim 12, The reference value is a charge amount (SOC) of the secondary battery,

CO: nickel-hydrogen secondary battery capacity Cs: self discharge amount (Ah) Ca: decrease over time (Ah) Td: Secondary battery end temperature (° C) during discharge Tc: Secondary battery end temperature (° C) during charging Δt: Sampling time (sec) id (t): secondary battery discharge current (A) ic (t): secondary battery charging current (A) Kd (Td, id (t)): secondary battery discharge efficiency at Td, id (t) Kc (Tc, ic (t)): Secondary battery charging efficiency at Tc, ic (t) Charge control method characterized in that obtained by. The method according to claim 9 or 12, Charging control method further comprises the step of displaying the comparison result in the comparison step to the outside via a wired / wireless network. In the method of controlling the charging of the secondary battery, the renewable energy such as solar, wind, fuel cells, etc. as a power source, the voltage change according to the state of charge is small, Measuring the voltage, temperature, and current of the secondary battery charged by the power supply; Comparing the measured temperature with a pre-stored reference temperature to terminate charging when the temperature is higher than the reference temperature; Calculating a charging amount using the measured current, voltage, and temperature values when the temperature is lower than the reference temperature; Terminating the charging when the calculated charging amount is 100% or more; Performing charging with a charge end voltage at a measured temperature when the calculated charge amount is less than 100%; Charging control method comprising a. The method of claim 15, Displaying the results of the temperature comparison step and the charge amount comparison step to the outside through a wired / wireless network; Charge control method characterized in that it further comprises.

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