JP2015180179A - Charger - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a charger capable of charging a various types of battery sets.SOLUTION: A charger 1 for charging a battery set 2A having secondary batteries is configured to control at least either a charge voltage or a charge current of the battery set by a digital signal. The charger 1 includes: a voltage reference value output part 9 which sets a voltage reference value of the charge voltage, and a current reference value output part 8 which sets a current reference value of the charge current. The control part of the charger includes: a charge voltage control circuit 70 which compares a detected charge voltage with the voltage reference value output from the voltage reference value output part; and a charge current control circuit 60 which compares a detected charge current with the current reference value output from the current reference value output part, so that the charge voltage and the charge current become the corresponding reference values, on the basis of the result of the comparison from the charge voltage control circuit and the charge current control circuit.

Description

  The present invention relates to a charging device, and more particularly to a charging device suitable for charging a secondary battery used as a power source for a cordless power tool.

  Conventionally, a battery pack containing a battery set composed of secondary batteries has been used as a power source for various electric devices, and at the same time, a charging device for charging the battery set contained in the battery pack has been widely used. ing. For example, a battery set is charged by constant current and constant voltage charge control, and the reference voltage is divided by a plurality of resistors as a reference value when setting a target voltage value in the constant voltage control section and a target current value in the constant current control section. There is known a charging device using the measured value. (Patent Document 1). In such a charging device, the number of resistors and the resistance value for determining a reference value when setting a target voltage value is set for a battery set having the same maximum charging voltage value of the secondary battery but different only in the number of cells. Is stipulated. In addition, the number of resistors and the resistance value that determine the reference value when setting the target current value assuming only the allowable current value of the battery set to be charged are also determined.

JP 2009-106117 A

  In recent years, secondary batteries have been increased in capacity. For example, the maximum charging voltage value of a lithium ion battery is generally 4.1 to 4.2 V per cell. Has been developed, and it is expected that the capacity will increase further in the future. Also, it is expected that secondary batteries having various values of allowable current values will be developed. For example, a battery set having 4 cells of a 4.35V secondary battery and 5 cells of 4.5V secondary batteries. A wide variety of battery sets such as battery sets are expected to be developed in the future. In such a situation, although the battery set assumed as the charging target in the above charging apparatus can be charged appropriately, the performance of each battery set is maximized for each of a plurality of types of battery sets. Since charging which can be performed cannot be performed, a charging device capable of appropriately charging a plurality of types of battery sets has been desired. In addition, although the battery set assumed as a charging target in the above charging device can be reliably and quickly charged, it may not be able to reliably charge a battery set having a different allowable current value. There has been a demand for a charging device that can reliably and quickly charge the battery set.

  Then, an object of this invention is to provide the charging device which can set the target voltage value for charging several types of battery groups appropriately. Another object of the present invention is to provide a charging device capable of setting a target current value for reliably and quickly charging a plurality of types of battery sets having different allowable current values.

  In order to solve the above problems, the present invention is a charging device for charging a battery set having a secondary battery, wherein at least one of a charging voltage and a charging current of the battery set is controlled by a digital signal. A charging device is provided.

  According to such a configuration, since at least one of the charging voltage and the charging current is controlled by a digital signal, various types of control can be performed as compared with the charging device described in Patent Document 1.

  In the above configuration, a reference value output unit that sets at least one reference value of the charging voltage and the charging current based on the digital signal, and controls at least one of the charging voltage and the charging current based on the reference value It is preferable to provide a control unit.

  According to such a configuration, since at least one reference value of the charging voltage and the charging current can be set based on the digital signal, the reference value for the control as compared with the charging device described in Patent Document 1. Can be set more.

  The reference value output unit includes a voltage reference value output unit that sets a voltage reference value of the charging voltage, and a current reference value output unit that sets a current reference value of the charging current, and the control unit Is preferably controlled based on the digital signal so that the charging voltage and the charging current become the corresponding reference values.

  According to such a configuration, the charging voltage and the charging current can be controlled to various values, and a wide variety of battery sets can be reliably and rapidly charged.

Charging means for charging the battery set; and the control unit compares the detected charging voltage with the voltage reference value output from the voltage reference value output unit, and the detected charging A charging current control unit that compares a current and the current reference value output from the current reference value output unit;
And the charging means is configured such that the charging voltage and the charging current become the corresponding reference values based on the comparison results from the charging voltage control unit and the charging current control unit.

In order to solve the above problems, the present invention further includes a charging means for charging a battery set having one or more secondary batteries, a digital signal output means for outputting an n-bit digital signal, and an output from the digital signal output means. In response to the digital signal, target signal output means for outputting a target signal indicating a target voltage corresponding to the value of the digital signal from 2 ⁿ target voltages, and based on the target signal target signal There is provided a charging device comprising charging voltage control means for controlling the charging voltage to be the target voltage.

According to this construction, it becomes possible to select a target voltage at the time of charging from the 2 ⁿ pieces of the target voltage in, the 2 ⁿ target voltage is settable. For this reason, it is possible to set a target voltage for properly charging a plurality of types of battery sets having different maximum charge voltage values of secondary batteries constituting the battery set.

  In the above configuration, the battery set is accommodated in a battery pack, and the digital signal output means acquires battery information from the battery pack and outputs the value of the digital signal output to the target signal output means based on the battery information. It is preferable to determine.

  According to such a configuration, since the value of the digital signal is determined based on the information acquired from the battery pack, it is possible to set an appropriate target voltage for the battery pack to be charged.

  Further, the battery information includes at least the maximum charging voltage value of the secondary battery, the number of cells of the secondary battery constituting the battery set, history information regarding the number of times of charging of the battery set, and characteristic information of the battery set. One piece of information is preferably included.

In order to solve the above problems, the present invention further includes a charging means for charging a battery set having one or more secondary batteries, a digital signal output means for outputting an n-bit digital signal, and an output from the digital signal output means. Reference value output means for outputting a reference value corresponding to the value of the digital signal from 2 ⁿ (n is an integer of 1 or more) reference values in response to the digital signal, and the 2 ⁿ Target voltage value selection means for selecting one target voltage value from 2 ⁿ target voltage values corresponding to each of the reference values in a one-to-one relationship, and the value of the charging voltage using the reference value And a charging voltage control means for controlling the charging voltage so as to be the target voltage value corresponding to the value.

According to such a configuration, it becomes possible to select a target voltage at the time of charging from the 2 ⁿ pieces of the target voltage in, the 2 ⁿ target voltage is settable. For this reason, it is possible to set a target voltage for properly charging a plurality of types of battery sets having different maximum charge voltage values of secondary batteries constituting the battery set.

Further, the 2 ⁿ reference values are a first reference corresponding to a first target voltage value for charging a first battery set whose maximum charging voltage value of the secondary battery is a first value. And a second reference value corresponding to a second target voltage value for charging a second battery set whose maximum charging voltage value of the secondary battery is a second value. .

  According to such a configuration, since it is possible to output the respective reference values for the target voltage values of the plurality of battery packs having different maximum charging voltage values of the secondary battery, it is possible to appropriately charge a plurality of types of battery packs. Can do.

Further, the reference value output means is a D / A converter or a digital potentiometer having n-bit resolution and capable of outputting 2 ⁿ reference voltages, and the reference voltage is preferably used as the reference value.

According to such a configuration, since a D / A converter or a digital potentiometer is employed as a reference value output unit, and 2 ⁿ reference voltages that can be output from the D / A converter or the digital potentiometer are used as a reference value, a simple configuration is achieved. Can output 2 ⁿ reference values.

  The battery set is housed in a battery pack, and the battery pack stores information on the target voltage value for charging the battery set, and information on the target voltage value is selected as the target voltage value. Battery-side communication means for communicating with the means, and the charging device further comprises charge-side communication means for communicating information on the target voltage value with the battery pack, and the target voltage value selecting means comprises the target voltage It is preferable to select the target voltage value based on information about the value.

  According to such a configuration, information on the target voltage value is acquired from the battery pack, so that the target voltage value can be used as it is, and there is no need to perform processing such as calculation on the charging device side.

  The battery set is housed in a battery pack, and the battery pack includes a storage unit that stores battery information related to the battery set, and a battery-side communication unit that communicates the battery information with the target voltage value selection unit. Preferably, the charging device further includes charging-side communication means for communicating the battery information with the battery pack, and the target voltage value selecting means preferably selects the target voltage value based on the battery information.

  According to such a configuration, the target voltage value can be selected based on the battery information stored in the battery pack, and therefore an appropriate target voltage can be selected for the battery pack.

  The battery information includes history information related to the charging history of the battery set and characteristic information related to the characteristics of the battery set, and the target voltage value selecting unit is configured to perform the operation based on the history information and the characteristic information. It is preferable to select a target voltage value.

  According to such a configuration, the target voltage value can be selected based on the characteristic information and the history information. For this reason, the target voltage value can be determined in consideration of the history information as compared with the case where the target voltage value is selected based only on the characteristic information, and for charging the battery pack to be charged more appropriately. A target voltage value can be selected.

  Moreover, it is preferable that the target voltage value selection unit selects a lower target voltage value as the number of times of charging increases.

  According to such a configuration, the target voltage value is set to a lower value as the number of times of charging increases, so that the secondary battery that has progressed deterioration can be charged with a lower target voltage value. For this reason, it can suppress that the secondary battery in which deterioration advanced further deteriorates, and can make a secondary battery long life.

In order to solve the above problems, the present invention further includes a charging means for charging a battery set having one or more secondary batteries, a digital signal output means for outputting an n-bit digital signal, and an output from the digital signal output means. Reference value output means for outputting a reference value corresponding to the value of the digital signal from 2 ⁿ (n is an integer of 1 or more) reference values in response to the digital signal, and the 2 ⁿ Target current value selection means for selecting one target current value from 2 ⁿ target current values corresponding to each of the reference values, and the charging current value corresponding to the reference value using the reference value There is provided a charging device comprising charging current control means for controlling the charging current so as to become a target current value.

According to such a configuration, the target current value at the time of charging can be selected from among the 2 ⁿ target current values, so that 2 ⁿ target current values can be set. For this reason, it is possible to set a target current value for appropriately charging a plurality of types of battery sets having different allowable current values of secondary batteries constituting the battery set.

In the above configuration, the 2 ⁿ reference values include a first reference value corresponding to a first target current value for charging the first battery set whose allowable current value is the first current value; It is preferable that the second reference value corresponding to the second target current value for charging the second battery set whose allowable current value is the second current value is included.

  According to such a configuration, since it is possible to output the respective reference values for the target current values of the plurality of battery packs having different allowable current values of the secondary battery, it is possible to appropriately charge a plurality of types of battery packs. it can.

Further, the reference value output means is a D / A converter or a digital potentiometer having n-bit resolution and capable of outputting 2 ⁿ reference voltages, and the reference voltage is preferably used as the reference value.

According to such a configuration, since a D / A converter or a digital potentiometer is employed as a reference value output unit, and 2 ⁿ reference voltages that can be output from the D / A converter or the digital potentiometer are used as a reference value, a simple configuration is achieved. Can output 2 ⁿ reference values.

  The battery set is housed in a battery pack, and the battery pack stores information on the target current value for charging the battery set, and information on the target current value is selected in the target current value selection. Battery-side communication means that communicates with the battery pack, and the charging device further comprises charge-side communication means that communicates information about the target current value with the battery pack, and the target current value selection means includes the target current value. It is preferable to select the target current value based on information about the value.

  According to such a configuration, since information on the target current value is acquired from the battery pack, the target current value can be used as it is, and there is no need to perform processing such as calculation on the charging device side.

  The battery set is housed in a battery pack, and the battery pack includes a storage unit that stores battery information related to the battery set, and a battery-side communication unit that communicates the battery information with the target current value selection unit. Preferably, the charging device further includes charging-side communication means for communicating the battery information with the battery pack, and the target current value selection means preferably selects the target current value based on the battery information.

  According to such a configuration, the target current value can be selected based on the battery information stored in the battery pack, and therefore an appropriate target current value can be selected for the battery pack.

  Further, the battery information includes history information related to the charging history of the battery set and characteristic information related to the characteristics of the battery set, and the target current value selection means is configured to perform the operation based on the history information and the characteristic information. It is preferable to select a target current value.

  According to such a configuration, the target voltage value can be selected based on the characteristic information and history information. For this reason, it is possible to determine the target current value in consideration of the history information as compared with the case of selecting the target current value based only on the characteristic information, and to charge the battery pack to be charged more appropriately. A target current value can be selected.

  Moreover, it is preferable that the target current value selection means selects a lower target current value as the number of times of charging increases.

  According to such a configuration, since the target current value is set to a lower value as the number of times of charging increases, the secondary battery that has progressed deterioration can be charged with a lower target current value. For this reason, it can suppress that the secondary battery in which deterioration advanced further deteriorates, and can make a secondary battery long life.

In the above configuration, charging current control means for controlling the charging current to be a target current value;
It is preferable to include target current value setting means for setting the target current value using a PWM signal.

  According to such a configuration, the target current value can be set by outputting a PWM signal.

  The target current value setting means preferably changes the target current value by changing the duty ratio of the PWM signal.

  According to such a configuration, since the target current value can be changed by changing the duty ratio, the target current value can be set steplessly to various values. For this reason, a wide variety of battery sets can be reliably and quickly charged.

  The target current value setting means preferably has a smoothing circuit that smoothes the PWM signal.

  According to such a configuration, the PWM signal is smoothed, so that the target current value can be set accurately.

  A voltage input unit capable of inputting an external voltage; a voltage storage unit that stores an external voltage value input to the voltage input unit; and a target based on the external voltage value stored in the voltage storage unit Target voltage value setting means for setting a voltage value, and the target current value setting means maintains the charge voltage at the stored external voltage value after the charge voltage reaches the target voltage value. It is preferable to change the target current value as described above.

  According to such a configuration, it is possible to accurately determine whether or not the charging voltage has reached the target voltage value by using a highly accurate external voltage value. In addition, the performance of the secondary battery can be maximized.

  The target voltage value setting means preferably sets the stored external voltage value as the target voltage value.

  According to such a configuration, since the external voltage value itself is set as the target voltage value, it is possible to more accurately determine whether the charging voltage has reached the target voltage value by using a highly accurate external voltage value. It is possible to make a determination, to further suppress the deterioration or failure of the secondary battery, and to maximize the performance of the secondary battery.

  In addition, it is preferable that the information acquisition unit further acquires battery information regarding the battery set, and the target current value setting unit sets the target current value based on the battery information.

  According to such a configuration, since the target current value is set based on the battery information, an appropriate target current value can be set for the battery set connected to the charging device, and the secondary battery included in the battery set is deteriorated. Or a failure can be suppressed more.

  Further, the information processing device further includes information acquisition means for acquiring battery information relating to the battery set, and the target voltage value setting means adds a value obtained by adding a predetermined value to the stored external voltage value based on the battery information. It is preferable to set it as a voltage value.

  According to such a configuration, an appropriate target voltage value is set for the battery set connected to the charging device in order to set a value obtained by adding a predetermined value to the external voltage value stored based on the battery information as the target voltage value. The deterioration or failure of the secondary battery included in the battery set can be further suppressed.

  Further, the apparatus further comprises information acquisition means for acquiring battery information relating to the battery set, and the target voltage value setting means is configured to reduce a value obtained by subtracting a predetermined value from the stored external voltage value based on the battery information. It is preferable to set it as a voltage value.

  According to such a configuration, in order to set a value obtained by subtracting a predetermined value from the external voltage value stored based on the battery information as a target voltage value, an appropriate target voltage value is set for the battery set connected to the charging device. The deterioration or failure of the secondary battery included in the battery set can be further suppressed.

  The battery information preferably includes a battery type that is a type of the battery set.

  According to such a configuration, since the battery type is included in the battery information, charging control according to the battery type can be performed. For this reason, deterioration or failure of the secondary battery can be further suppressed, and the performance of the secondary battery can be utilized to the maximum.

  The battery information preferably includes a battery temperature that is the temperature of the battery set.

  According to such a configuration, it is possible to perform charge control according to the battery temperature, which is a factor that greatly affects the deterioration or failure of the secondary battery. For this reason, deterioration or failure of the secondary battery can be further suppressed, and the performance of the secondary battery can be utilized to the maximum.

  The battery information preferably includes the number of times of charging or discharging of the battery set.

  According to such a configuration, since the battery information includes the number of times of charging or discharging, which is an index indicating the degree of deterioration of the secondary battery, charging according to the degree of deterioration of the secondary battery estimated from the number of times of charging or discharging. Control can be performed. For this reason, deterioration or failure of the secondary battery can be further suppressed, and the performance of the secondary battery can be utilized to the maximum.

  In order to solve the above-described problems, the present invention further provides a charging device for charging a battery set having a secondary battery, the charging current control means for controlling the charging current to be a target current value, and a digital signal. And a target current value setting means for setting the target current value using a certain PWM signal.

  According to such a configuration, since at least one of the charging voltage and the charging current is controlled by a digital signal, various types of control can be performed as compared with the charging device described in Patent Document 1. Further, the target current value can be set by the PWM signal.

  According to the charging device of the present invention, a target voltage value for appropriately charging a plurality of types of battery sets can be set. Further, it is possible to set a target current value for reliably and quickly charging a plurality of types of battery sets having different allowable current values.

1 is a circuit diagram including a block diagram of a charging device according to a first embodiment of the present invention. It is a table which shows the battery information which the charge side microcomputer of the charging device concerning the 1st Embodiment of this invention and the battery side microcomputer of a battery pack have memorize | stored. It is a figure which shows the setting range and setting number of the target voltage value and target current value in the charging device concerning the 1st Embodiment of this invention, (a) is the setting range and setting number of a target current value, ( b) is a settable range and settable number of target voltage values. It is a flowchart which shows the charge control by the charging device concerning the 1st Embodiment of this invention. It is a flowchart which shows the charge control by the charging device concerning the 2nd Embodiment of this invention. It is a table which shows the battery information which the charge side microcomputer of the charging device concerning the 2nd Embodiment of this invention has memorize | stored. It is a circuit diagram including the block diagram of the charging device concerning the 3rd Embodiment of this invention. It is a figure which shows the connection of the charging device and voltage output device in the case of memorize | storing a comparison reference bit value in the charging device concerning the 3rd Embodiment of this invention. In the charging device according to the third embodiment of the present invention, the setting PWM signal output from the PWM signal output port and the smoothing comparison voltage output from the current reference value output circuit are shown. ) Shows the case where the duty ratio of the setting PWM signal is 75%, and (b) shows the case where the duty ratio of the setting PWM signal is 25%. It is a flowchart which shows the charge control by the charging device concerning the 3rd Embodiment of this invention. It is a flowchart which shows the charge control by the charging device concerning the 3rd Embodiment of this invention. It is a figure which shows the target electric current value determination table based on the connection structure memorize | stored in the memory | storage part of the charging device concerning the 3rd Embodiment of this invention. It is a figure which shows the target electric current value determination table based on the battery temperature memorize | stored in the memory | storage part of the charging device concerning the 3rd Embodiment of this invention. It is a figure which shows the target voltage value determination table based on the number of cells memorize | stored in the memory | storage part of the charging device concerning the 3rd Embodiment of this invention. It is a figure which shows the target voltage value determination table based on the maximum charging voltage memorize | stored in the memory | storage part of the charging device concerning the 3rd Embodiment of this invention. It is a figure which shows the target voltage value determination table based on the frequency | count of charging / discharging memorize | stored in the memory | storage part of the charging device concerning the 3rd Embodiment of this invention. It is a figure which shows the time change of the charging current and charging voltage in the charging control by the charging device concerning the 3rd Embodiment of this invention.

  A charging apparatus 1 according to a first embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a circuit diagram including a block diagram illustrating a configuration of a circuit inside the charging device 1 and a circuit inside the battery pack 2 attached to the charging device 1.

  First, the battery pack 2 will be described. As shown in FIG. 1, the battery pack 2 includes a battery set 2A, a protection IC 2b, a battery side power supply circuit 2c, a battery side microcomputer 2d, a battery side memory 2e, and a temperature sensitive element 2f.

  The battery set 2A has a configuration in which four battery cells 2a are connected in series. In the present embodiment, for example, the battery cell 2a is a lithium ion battery with a rated voltage of 3.6V, and the maximum charging voltage value is 4.2V. The maximum charging voltage value of the battery set 2A as a whole is 16.8V (4.2V / cell × 4 cells). Further, the allowable current value of the battery cell 2a is 6A, and the allowable current value of the battery set 2A as a whole is also 6A.

  The protection IC 2b monitors the voltage of each battery cell 2a, and outputs an abnormal signal to the battery-side microcomputer 2d when any one of them becomes an abnormal state due to overcharge or overdischarge. The battery side power supply circuit 2c transforms the voltage of the plurality of battery cells 2a and supplies the power to the battery side microcomputer 2d.

  The temperature sensitive element 2f is provided adjacent to the battery set 2A, detects the temperature of the battery set 2A, and outputs the detection result to the battery side microcomputer 2d.

  The battery side memory 2e stores battery information and the table shown in FIG. Specifically, the battery-side memory 2e uses, as battery information, the number of battery cells 2a constituting the battery set 2A, the maximum charge voltage value (voltage per cell) of the battery cell 2a, and the battery set 2A for proper charging Characteristic information relating to the characteristics of the battery set 2A necessary for charging the battery set 2A, such as a target voltage value, an allowable current value at the time of charging, and an end current value for terminating the charging, is mainly stored. . The battery-side memory 2e also stores history information related to the charging history such as the number of times of charging and the number of abnormal signals as battery information.

  The table shown in FIG. 2 shows a target voltage value and a digital signal (based on the number of secondary batteries constituting the battery set and the maximum charging voltage value of the secondary battery (maximum charging voltage value per cell)). The correspondence with a to o) is shown. Specifically, for each of the three types of secondary batteries having a maximum charging voltage value of 4.2V, 4.35V, and 4.5V, a target voltage value corresponding to the number of cells and a digital corresponding to each target voltage value The signal is shown. For example, when the number of cells of the secondary battery constituting the battery set is 5 and the maximum charging voltage value of the secondary battery is 4.5 V, the target voltage value is 22.5 V, and the target voltage value (22 The digital signal corresponding to .5V) is i. Further, when the number of cells of the secondary battery constituting the battery set is 7 cells and the maximum charging voltage value of the secondary battery is 4.35V, the target voltage value is 30.45V, and the target voltage value (30 The digital signal corresponding to .45V) is k.

  In the table shown in FIG. 2 in the present embodiment, as the target voltage value for properly charging the battery set, the maximum charge of the secondary battery constituting the battery set in order to maximize the performance of the secondary battery. A value obtained by multiplying the voltage value by the number of cells of the secondary battery constituting the battery set (hereinafter, the battery set maximum charging voltage value) is employed. The target voltage value for properly charging the battery set is not limited to the battery set maximum charge voltage value, but may be a value within a range in which the performance of the secondary battery can be utilized, based on the characteristics and state of the secondary battery. It is preferable to determine appropriately. Note that the target voltage value for properly charging a battery set is appropriate when the battery capacity is important, and the battery pack maximum charge voltage value is appropriate. Also, a small value (the lifetime is extended but the capacity cannot be secured if the value is small), and the optimum value varies depending on the type of battery such as a battery manufacturer). That is, considering both capacity and life, a value that is several percent lower than the maximum charging voltage value (eg, 4.18 V / cell in the case of 4.2 V / cell) is appropriate. The battery side memory 2e corresponds to a storage unit.

  The battery-side microcomputer 2d includes a ROM, a RAM, an arithmetic function, and the like, and is connected to the protection IC 2b, the battery-side power supply circuit 2c, the battery-side memory 2e, and the temperature sensitive element 2f. Moreover, the battery side microcomputer 2d is provided with the information communication port 2g, and mutually communicates various information with the charging device 1 via the information communication port 2g. The information communication port 2g corresponds to battery side communication means.

  The battery-side microcomputer 2d transmits battery information and a digital signal derived from the table of FIG. 2 to the charging device 1 via the information communication port 2g during charging. In the present embodiment, since the number of battery cells 2a constituting the battery set 2A is 4, the maximum charging voltage value of the battery cell 2a is 4.2V, and the target voltage value is 16.8V, the battery side microcomputer 2d transmits d to the charging device 1 as a digital signal. In addition, when an abnormal signal is input from the protection IC 2b to the battery-side microcomputer 2d, the battery-side microcomputer 2d outputs a charging abnormality stop signal to the charging device 1 via the information communication port 2g. Furthermore, the battery-side microcomputer 2d receives the charge count stored in the battery-side memory 2e when a charging stop signal indicating that charging of the battery set 2A has been completed is transmitted from the charging device 1 via the information communication port 2g. Is configured to be updatable.

  Next, the charging device 1 will be described. The charging device 1 includes a first rectifying / smoothing circuit 10, a switching circuit 20, a second rectifying / smoothing circuit 30, an auxiliary power circuit 40, a switching power circuit 6, a charging side microcomputer 50, a charging current control circuit 60, The current reference value output unit 8, the battery voltage detection circuit 7, the display circuit 80, the charge voltage control circuit 70, the voltage reference value output unit 9, and the charge control signal transmission units 4 and 5 are mainly configured. In the state where the battery pack 2 is mounted, the battery set 2A (battery cell 2a) inside the battery pack 2 is charged by constant current constant voltage charge control. The constant current / constant voltage charging control means that when charging is started, charging is performed while controlling the charging current to a constant current value (target current value) (constant current control section), and the voltage of the entire battery set 2A is set as a target. After reaching the voltage value, charging is performed while maintaining the charging voltage at the target voltage value (constant voltage control section), and charging is terminated when the charging current falls below a predetermined end current value in the constant voltage control section. Control.

  The first rectifying / smoothing circuit 10 includes a full-wave rectifying circuit 11 and a smoothing capacitor 12. The full-wave rectifying circuit 11 performs full-wave rectification on the AC voltage supplied from the AC power supply 90, and the smoothing capacitor 12. Smoothes and outputs a DC voltage. The AC power supply 90 is an external power supply such as a commercial power supply.

  The switching circuit 20 is connected to the first rectifying / smoothing circuit 10 and includes a high-frequency transformer 21, a MOSFET 22, and a PWM control IC 23. The PWM control IC 23 changes the drive pulse width of the MOSFET 22, the MOSFET 22 performs switching according to the drive pulse width, and the DC output from the first rectifying and smoothing circuit 10 is used as the voltage of the pulse train waveform. The voltage of the pulse train waveform is applied to the primary winding of the high frequency transformer 21, and is stepped down (or boosted) by the high frequency transformer 21 and output to the second rectifying and smoothing circuit 30.

  The second rectifying / smoothing circuit 30 includes a diode 31, a smoothing capacitor 32, and a discharging resistor 33. The second rectifying / smoothing circuit 30 rectifies and smoothes the output voltage obtained from the secondary winding of the high-frequency transformer 21 to generate a DC voltage. The DC voltage is generated and output from the positive terminal 1 a and the negative terminal 1 b of the charging device 1.

  The current detection resistor 3 is connected between the second rectifying / smoothing circuit 30 and the minus terminal 1 b and detects a charging current flowing through the battery pack 2. The charging current is detected by inverting and amplifying a voltage drop caused by the current flowing through the current detection resistor 3 in an operational amplifier 61 described later, and inputting the value to an A / D input port 52 described later of the charging side microcomputer 50. Do.

  The auxiliary power supply circuit 40 is connected to the first rectifying and smoothing circuit 10 and is a constant voltage power supply circuit for supplying a stabilized reference voltage Vcc to various circuits such as the charging side microcomputer 50 and operational amplifiers 61 and 65 described later. is there. The auxiliary power supply circuit 40 is mainly composed of coils 41a, 41b and 41c, a switching element 42, a control element 43, a rectifier diode 44, a three-terminal regulator 46, oscillation prevention capacitors 45 and 47, and a reset IC 48. It is configured. The reset IC 48 is an IC that outputs a reset signal to the charging side microcomputer 50 and resets the charging side microcomputer 50.

  The switching power supply circuit 6 is a rectifying / smoothing circuit connected to the auxiliary power supply circuit 40, the switching circuit 20 and the like and serving as a power supply for the PWM control IC 23. The switching power supply circuit 6 is mainly composed of a coil 6a, a rectifying diode 6b, and a smoothing capacitor 6c. ing.

  The charging-side microcomputer 50 includes a first output unit 51a, an A / D input port 52, a digital communication port 53, a reset port 54, a ROM (not shown), a RAM (not shown), and an arithmetic device (not shown). It is mainly configured by. The charging side microcomputer 50 processes various signals input to the A / D input port 52 and the digital communication port 53, and outputs various signals based on the results from the first output unit 51a and the digital communication port 53 to the display circuit 80, the current. It outputs to the reference value output unit 8, the voltage reference value output unit 9, etc., and controls the operation of the charging device 1. A table (not shown) mainly stores the table shown in FIG. The charging side microcomputer 50 corresponds to a control unit, digital signal output means, target voltage value selection means, target current value setting means, and charging side communication means.

  The first output unit 51 a has a plurality of ports, and each is connected to the display circuit 80 and the charge control signal transmission unit 4. The digital communication port 53 is connected to the information communication port 2g of the battery pack 2 and is configured to be capable of bidirectional communication. The digital communication port 53 is connected to the current reference value output unit 8 and the voltage reference value output unit 9, and can transmit a 10-bit digital signal to each of the current reference value output unit 8 and the voltage reference value output unit 9. It is configured. The reset port 54 is connected to the auxiliary power circuit 40.

  The current reference value output unit 8 is an element for setting a target current value in the constant current control section, and includes a D / A converter having a 10-bit resolution. The current reference value output unit 8, that is, the D / A converter, is connected to the digital communication port 53 and the charging current control circuit 60 of the charging side microcomputer 50, and according to a 10-bit digital signal transmitted from the digital communication port 53. A voltage for comparison corresponding to the target current value is output to the charging current control circuit 60. The current reference value output unit 8 corresponds to a reference value output unit.

  In this embodiment, since the D / A converter has a 10-bit resolution, the predetermined voltage range can be decomposed into 1024 gradations, and a maximum of 1024 types of comparison voltages can be output within the predetermined voltage range. it can. Further, the 1024 types of comparison voltages within the predetermined voltage range correspond to the 1024 types of target current values within the range of the target current values I1 to I2, and as a result, as shown in FIG. 1024 types of target current values can be set within the range of current values I1 to I2 (I1> I2).

  In this embodiment, as an example, the current value I1 is 6.115A, the current value I2 is 1A, and 1024 kinds of current values are set as target current values in increments of 5 mA within the range from 1A to 6.115A. Can do. For example, when the target current value is set to the current value I1 (6.115A), the digital signal [1111111111] (corresponding to the decimal number 1023) may be output from the digital communication port 53 to the D / A converter. When set to I2 (1A), a digital signal [0000000000000] (corresponding to decimal 0) may be output. When the target current value is set to 5 A, the target current value can be set to 5 A by outputting a digital signal [1110000000] (corresponding to decimal number 800) from the digital communication port 53.

  In the present embodiment, since the target current value can be set in increments of 5 mA in the range of 1A to 6.115A, for example, a battery set with a desired current value of 6A, a battery set with 5.8A, and a battery with 3.2A Each desired current value can be set as a target current value for all of these battery sets such as a set and a 2.5 A battery set (secondary battery). The target current value for properly charging the battery set is a desired current value, and the battery set can be charged quickly and reliably by setting the desired current value as the target current value and performing charging.

  On the other hand, in the case of the charging device as described in Patent Document 1 having a configuration in which the target current value can be set only in increments of 1A in the range of 1A to 6A, it is appropriate for a battery set having an allowable current value of 6A. Although the target current value for charging can be set, a battery set with an allowable current value of 5.8A must be charged at 5A which does not exceed 5.8A, and the charging time becomes long. Occurs. Similarly, the battery sets having allowable current values of 3.2A and 2.5A must be charged with 3A and 2A, respectively, and the charging time is long.

  As described above, in the charging device as described in Patent Document 1, the target current value cannot be set to an appropriate current value according to the type (allowable current value) of the battery set to be charged. Although charging could not be performed, in the present embodiment, a target current value for proper charging can be set according to the type of battery set having various allowable current values, and charging can be performed reliably and quickly.

  In this embodiment, a D / A converter having a 10-bit resolution is used for the current reference value output unit 8, but the same effect can be obtained even if a digital potentiometer having a 10-bit resolution is used. . A digital potentiometer with 10-bit resolution changes the resistance value based on a digital signal to decompose a predetermined voltage range into 1024 gradations, and outputs a maximum of 1024 comparison voltages within the predetermined voltage range. It is an element that can output.

  The charging current control circuit 60 includes operational amplifiers 61 and 65, resistors 62, 63, 64, 66 and 67, and a diode 68. The output terminal of the operational amplifier 61 is connected to the A / D input port 52, the inverting input terminal of the operational amplifier 61 is connected to the current detection resistor 3, and the non-inverting input terminal of the operational amplifier 65 is connected to the current reference value output unit 8. The output terminal 65 is connected to the charging control signal transmission unit 5 through a resistor 67 and a diode 68.

  The charging current control circuit 60 inverts and amplifies the comparison voltage corresponding to the charging current input to the inverting input terminal of the operational amplifier 61 and inputs the voltage to the inverting input terminal of the operational amplifier 65, and corresponds to the charging current. The comparison voltage and the comparison voltage corresponding to the target current value input to the non-inverting input terminal of the operational amplifier 65 from the current reference value output unit 8 are compared, and the PWM control IC 23 is connected via the charge control signal transmission unit 5. The charging current is controlled by outputting a signal corresponding to the comparison result.

  The battery voltage detection circuit 7 is a circuit that detects a battery voltage, and includes resistors 7a and 7b. The resistors 7a and 7b are connected in series between the positive terminal 1a of the charging device 1 and the ground, and the connection point between the resistors 7a and 7b is connected to the A / D input port 52 of the charging side microcomputer 50. Yes. The voltage supplied to the battery pack 2, that is, the voltage of the battery pack 2 is divided by the resistors 7a and 7b, and the value is input to one of the A / D input ports 52 of the charging side microcomputer 50 as battery voltage information.

  The charge control signal transmission unit 4 includes a photocoupler 4a and an FET 4b. The photocoupler 4a is connected between the switching circuit 20 and the switching power supply circuit 6, and transmits a signal for controlling the start / stop of the PWM control IC 23. The FET 4b is connected between the light emitting element constituting the photocoupler and the ground, and the gate of the FET 4b is connected to the first output unit 51a. When the port connected to the FET 4b in the first output unit 51a of the charging side microcomputer 50 outputs a high signal, the FET 4b is turned on and the photocoupler of the charge control signal transmission unit 4 is turned on. As a result, the PWM control IC 23 is activated and charging is started. Further, when a port connected to the FET 4b in the first output unit 51a outputs a low signal, the FET 4b is turned off, and the photocoupler of the charge control signal transmission unit 4 is turned off. As a result, the PWM control IC 23 stops and charging stops (ends).

  The charging control signal transmission unit 5 includes a photocoupler and the like, and feeds back the charging voltage and charging current signals from the charging voltage control circuit 70 and the charging current control circuit 60 to the PWM control IC 23. The charging current control means is mainly configured by the charging current control circuit 60, the charging control signal transmission unit 5, and the PWM control IC 23.

  The display circuit 80 is a circuit for displaying the state of charge, and includes an LED 81 and resistors 82 and 83. When the port connected to the resistor 82 in the first output unit 51a outputs a high signal, the LED 81 lights red. When the port connected to the resistor 83 in the first output unit 51a outputs a high signal, the LED 81 Lights green, and when a high signal is output from both ports, the LED 81 lights orange. In the present embodiment, the charging-side microcomputer 50 turns on the red LED 81 in a state before charging when the battery pack 2 is not connected or waiting for charging, and turns on orange by simultaneously lighting two LEDs 81 during charging. The LED 81 is lit in green after charging.

  The voltage reference value output unit 9 is an element for setting a target voltage value in the constant voltage control section, and includes a D / A converter having a 10-bit resolution. The voltage reference value output unit 9, that is, the D / A converter, is connected to the digital communication port 53 and the charge voltage control circuit 70 of the charge side microcomputer 50, and the charge voltage control is performed according to the digital signal transmitted from the digital communication port 53. A comparison voltage corresponding to the target voltage value is output to the circuit 70. The voltage reference value output unit 9 corresponds to a reference value output unit.

  In this embodiment, since the D / A converter has a 10-bit resolution, the predetermined voltage range can be decomposed into 1024 gradations, and a maximum of 1024 types of comparison voltages can be output within the predetermined voltage range. it can. Further, since the 1024 types of comparison voltages within the predetermined voltage range correspond to the 1024 types of target voltage values within the range of the target voltage values V1 to V2, as a result, as shown in FIG. In the range of voltage values V1 to V2 (V1> V2), 1024 types of target voltage values can be set.

  In this embodiment, as an example, the voltage value V1 is 61.15V, the voltage value V2 is 10V, and 1024 types of target voltage values can be set in increments of 50mV within a range from 10V to 61.15V. For example, when the target voltage value is set to the voltage value V1, the digital signal [1111111111] (corresponding to the decimal number 1023) may be output from the digital communication port 53 to the D / A converter, and the voltage value V2 is set. May output a digital signal [0000000] (corresponding to decimal 0). When the target voltage value is set to 16.8V, a digital signal [0010001000] (corresponding to decimal number 136) may be output from the digital communication port 53. When the target voltage value is set to 45V, May output the digital signal [1010111100] (corresponding to decimal number 700) from the digital communication port 53.

  In the present embodiment, since the target voltage value can be set in increments of 50 mV in the range of 10V to 61.15V, for example, a battery set (target voltage value) having three secondary batteries with a maximum charging voltage value of 4.2V. 12.6V), a battery set having 7 cells of secondary batteries having a maximum charging voltage value of 4.35V (target voltage value is 30.45V), and 10 batteries having a maximum charging voltage value of 4.5V. A battery group having a cell (target voltage value is 45V), and an appropriate target voltage value can be set for all of these battery groups. In this way, it is possible to set a target voltage value for appropriately charging a wide variety of battery sets having different maximum charge voltage values and cell numbers of secondary batteries.

  On the other hand, in the case of the charging device as described in Patent Document 1 in which only the battery set in which the number of cells of the secondary battery is 1 to 4 and the maximum charging voltage value of the secondary battery is 4.2 V is to be charged. 4V (corresponding to 1 cell), 8.4V (corresponding to 2 cells), 12.6V (corresponding to 3 cells), 16.8V (corresponding to 4 cells), only 4 target voltage values It cannot be set, and among the above three types of battery sets, a battery set having three secondary batteries with a maximum charge voltage value of 4.2 V can be charged properly, but the maximum charge voltage value is 4.35 V, 4 When charging secondary batteries of .5V, the secondary battery may be charged to full charge without charging it as a target voltage value that is lower than the target voltage value for properly charging these secondary batteries. Could not charge properly.

  Thus, in the charging device as described in Patent Document 1, the target voltage value cannot be set to an appropriate value according to the type of battery set to be charged (the maximum charging voltage value of the secondary battery, the number of cells). Therefore, charging that makes the best use of the performance of the battery set to be charged could not be performed, but in the present embodiment, a target charging voltage value for appropriately charging can be set according to the type of the battery set to be charged. It is possible to charge the battery set so as to maximize the performance of the battery set.

  In the present embodiment, a D / A converter having a 10-bit resolution is used for the voltage reference value output unit 9, but the same effect can be obtained even if a digital potentiometer having a 10-bit resolution is used. . A digital potentiometer with 10-bit resolution changes the resistance value based on a digital signal to decompose a predetermined voltage range into 1024 gradations, and outputs a maximum of 1024 comparison voltages within the predetermined voltage range. It is an element that can output.

  The charging voltage control circuit 70 is a circuit that controls the charging voltage, and includes an operational amplifier 71, a diode 72, and resistors 73 and 74. The resistors 73 and 74 are connected in series between the plus terminal 1 a of the charging device 1 and the ground, and the connection point between the resistor 73 and the resistor 74 is connected to the inverting input terminal of the operational amplifier 71. The non-inverting input terminal of the operational amplifier 71 is connected to the voltage reference value output unit 9, and the output terminal is connected to the charging control signal transmission unit 5 via the diode 72.

  The voltage supplied to the battery pack 2, that is, the charging voltage is divided by the resistor 73 and the resistor 74, and the divided voltage is input to the inverting input terminal of the operational amplifier 71 as a comparison voltage corresponding to the charging voltage. . The comparison voltage corresponding to the target voltage value is input from the voltage reference value output unit 9 to the non-inverting input terminal of the operational amplifier 71.

  The charging voltage control circuit 70 corresponds to the comparison voltage corresponding to the charging voltage input to the inverting input terminal of the operational amplifier 71 and the target voltage value input to the non-inverting input terminal of the operational amplifier 71 from the voltage reference value output unit 9. The charging voltage is controlled by comparing with the comparison voltage to be output and outputting a signal corresponding to the comparison result to the PWM control IC 23 via the charging control signal transmission unit 5. The charging voltage control means is mainly configured by the charging voltage control circuit 70, the charging control signal transmission unit 5, and the PWM control IC 23.

  Next, an example of charge control of the charging apparatus 1 according to the first embodiment of the present invention will be described with reference to the flowchart of FIG.

  First, when the AC power supply 90 and the charging apparatus 1 are connected, the charging side microcomputer 50 starts operation, and the display circuit 80 is lit in red to indicate that it is in a charging standby state before charging (step 201). In order to light the display circuit 80 in red, a high signal is output from the port connected to the resistor 82 in the first output unit 51a, and the LED 81 is lighted in red.

  Next, it is determined whether or not the battery pack 2 is mounted on the charging device 1 (step 202). Whether or not the battery pack 2 is mounted is determined by communication between the battery side microcomputer 2d and the charging side microcomputer 50 via the information communication port 2g. If it is determined in step 202 that the battery pack 2 is not mounted on the charging device 1, step 201 and step 202 are repeated until the battery pack 2 is mounted on the charging device 1, and the charging standby state is continued.

  On the other hand, when it is determined in step 202 that the battery pack 2 is mounted on the charging device 1, the type of battery is determined (step 203). In step 203, the charging-side microcomputer 50 communicates with the battery-side microcomputer 2d via the information communication port 2g, and acquires the battery information stored in the battery-side memory 2e of the battery pack 2, thereby selecting the battery type. Determine. Since the maximum charging voltage value of the battery cell 2a of the battery set 2A in the present embodiment is 4.2V, the number of cells is 4 cells, and the target current value is 16.8V, the battery side microcomputer 2d is connected to the charging side microcomputer 50. The charging-side microcomputer 50 acquires a digital signal “d” as battery information. In addition, the charging-side microcomputer 50 acquires information such as an allowable current value (6A) and a termination current value for terminating charging in the communication.

  The charging side microcomputer 50 determines the type of the battery by comparing the acquired digital signal (d) with the table shown in FIG. 2 stored in the ROM (not shown). Specifically, the battery set 2A to be charged from the digital signal (d) has four battery cells 2a having a maximum charge voltage value of 4.2V, and is used for properly charging the battery set 2A. It is determined that the target voltage value is 16.8V. Thereafter, the charging side microcomputer 50 sets a target voltage value according to the type of battery (step 204). In step 204, in order to set the target voltage value to 16.8V, the digital signal [0010001000] (corresponding to decimal number 136) may be output from the digital communication port 53 to the voltage reference value output unit 9.

  In the present embodiment, the battery pack 2 transmits the digital signal (d). However, when the digital signal (h) is transmitted from the battery pack 2, for example, the charging side microcomputer 50 sets the battery set 2A to be charged. Determines that the target voltage value for properly charging the battery set 2A is 21.75V, and the target voltage value is 21. The digital signal [0011101011] (corresponding to decimal number 235) is output from the digital communication port 53 to the voltage reference value output unit 9 to set to .75V.

  In the present embodiment, the target voltage value for properly charging the battery set 2A is set based on the digital signals (a to o) transmitted from the battery pack 2, but for example, the battery pack 2 An identification resistor is provided, the identification resistor is connected in series with another voltage dividing resistor, and the type of battery is identified by a divided voltage value obtained by dividing the reference voltage Vcc by the identification resistor and the voltage dividing resistor. A voltage value may be set. For example, when the value of the identification resistor is T1, the target voltage value for properly charging the battery set with a battery set having three secondary batteries with a maximum charge voltage value of 4.2 V is 12. When the value of the identification resistance is T2, the target voltage value for properly charging the battery set in the battery set having four secondary batteries with the maximum charge voltage value of 4.5V is 18V. It is good.

  Next, the target current value is set to I1 (step 205). In order to set the target current value to I1 (6A), the digital signal [1111101000] (corresponding to decimal number 1000) may be output from the digital communication port 53 to the current reference value output unit 8.

  Charging is started after the target current value is set in step 205 (step 206). To start charging, a high signal is output from the port connected to the FET 4b in the first output unit 51a of the charging side microcomputer 50, and the PWM control IC 23 is activated. At the same time as charging is started, a charging start signal is output to the battery pack 2 via the information communication port 2g. Further, when charging is started, the display circuit 80 is lit in orange to indicate that charging is in progress (step 207). In order to turn on the display circuit 80 in orange, the LED 81 is lit in orange by outputting a high signal from the port connected to the resistor 82 and the port connected to the resistor 83 in the first output unit 51a.

  In the constant current control section, the battery set 2A is charged with the target current value I1. After that, when the voltage of the battery group 2A reaches the set target voltage value (16.8V), the process proceeds to the constant voltage control section, and charging is continued while maintaining the charging voltage at the target voltage value. In the constant voltage control section, it is determined whether or not the charging current has become equal to or less than the end current value (step 208). If it is determined in step 208 that the charging current is not less than the end current value, step 208 is repeated until the charging current becomes less than the end current value, and charging is continued. If it is determined that the charging current is equal to or less than the termination current value, the charging is terminated (S209). To end the charging, a low signal is output from the port connected to the FET 4b in the first output unit 51a of the charging side microcomputer 50, and the PWM control IC 23 is stopped.

  When the charging is completed, a charging end signal is output to the battery pack 2. When the charging end signal is input, the battery pack 2 updates the number of times of charging and stores it in the battery side memory 2e. The number of times of charging is used for determination of the degree of deterioration of the battery cell 2a during the subsequent charging. When charging is completed, the display circuit 80 is lit in green to indicate that charging is complete (step 210). In order to turn on the display circuit 80 in green in step 210, the LED 81 is lit in green by outputting a high signal from the port connected to the resistor 83 in the first output unit 51a.

  After the charging is finished and the display circuit 80 is lit in green, it is determined whether or not the battery pack 2 is detached from the charging device 1 (step 211). When it is determined that the battery pack 2 is not detached from the charging device 1, step 218 is repeated, and the state where the display circuit 80 is lit in green is maintained. On the other hand, when it is determined that the battery pack 2 is detached from the charging device 1, the process returns to step 201, and the display circuit 80 is lit in red indicating a standby state before charging. Then, steps 201 and 202 are repeated until the battery pack 2 is mounted again, and the charging standby state is continued.

  As described above, in the present embodiment, the reference target voltage value and the target current value can be finely set by the digital element as compared with the charging device described in Patent Document 1, and therefore, the two connected to the charging device. It can be optimally charged according to the characteristics of the secondary battery.

  Next, a charging apparatus 300 according to a second embodiment of the present invention will be described with reference to FIGS. The configuration, communication means, and the like of the charging device 300 are the same as those of the charging device 1, and information and charging control stored in a ROM (not shown) of the charging side microcomputer 50 of the charging device 300 are different from the charging device 1. Therefore, only different parts from the charging device 1 will be mainly described.

  A table shown in FIG. 5 is stored in a ROM (not shown) of the charging side microcomputer 50 of the charging apparatus 300. In the table shown in FIG. 5, the target for appropriately charging the battery set according to the number of cells of the secondary battery constituting the battery set, the maximum charge voltage value of the secondary battery (voltage per cell), and the number of times of charging. A voltage value and a target current value are defined. As the target voltage value in the table shown in FIG. 5, a lower voltage value is adopted as the target voltage value as the number of times of charging increases. The same applies to the target current value, and a smaller current value is adopted as the target current value as the number of times of charging increases.

  In general, the secondary battery deteriorates as the number of times of charging increases. When a secondary battery having a large deterioration degree is charged with the same target voltage value as a secondary battery having a low deterioration degree, the deterioration further proceeds. End up. For this reason, the degree of deterioration of the secondary battery is estimated from the number of times of charging, and the target voltage value is reduced stepwise as the number of times of charging increases, thereby reducing the burden on the secondary battery during charging and lengthening the secondary battery. Life expectancy.

  In addition, when a secondary battery that has deteriorated and has a high internal resistance is charged with the same target current value as a secondary battery that has a low degree of deterioration, the temperature of the secondary battery rises rapidly and the deterioration further proceeds. End up. For this reason, as with the target voltage value, the deterioration degree of the secondary battery is estimated from the number of times of charging, and as the number of times of charging increases, the target current value is gradually reduced to suppress the temperature rise during charging, The battery has a long life.

  Next, an example of charge control of the charging apparatus 300 will be described with reference to the flowchart of FIG.

  First, when the AC power supply 90 and the charging device 300 are connected, the charging-side microcomputer 50 starts operating, and the display circuit 80 is lit in red to indicate that it is in a charging standby state before charging (step 401). In order to light the display circuit 80 in red, a high signal is output from the port connected to the resistor 82 in the first output unit 51a, and the LED 81 is lighted in red.

  Next, it is determined whether or not the battery pack 2 is mounted on the charging device 300 (step 402). Whether or not the battery pack 2 is mounted is determined by communication between the battery side microcomputer 2d and the charging side microcomputer 50 via the information communication port 2g. If it is determined in step 402 that the battery pack 2 is not mounted on the charging device 300, step 401 and step 402 are repeated until the battery pack 2 is mounted on the charging device 300, and the charging standby state is continued.

  On the other hand, when it is determined in step 402 that the battery pack 2 is mounted on the charging device 300, the type of battery is determined (step 403). In step 403, the charging side microcomputer 50 determines the type of battery by communicating with the battery side microcomputer 2d via the information communication port 2g and acquiring the battery information stored in the battery side memory 2e of the battery pack 2. To do.

  For example, when the maximum charging voltage value of the battery cell 2a constituting the battery set 2A in the present embodiment is 4.2V and the number of cells is 3, the information is included in the battery information, and the charging side microcomputer 50 Determines from the acquired battery information that the number of battery cells 2a constituting the battery set 2A is 3, and the maximum charge voltage value (voltage per cell) of the battery cell 2a is 4.2V. Further, the charging-side microcomputer 50 acquires the number of times the battery set 2A has been charged so far in the communication, and simultaneously acquires information such as an allowable current value (6A) and a termination current value for terminating charging ( Step 404).

  Next, the charging-side microcomputer 50 compares the information acquired in steps 403 and 404 with the table shown in FIG. 5 stored in the ROM (not shown), and the target voltage value and target current for properly charging the battery set 2A. A value is set (step 405). Specifically, since the battery set 2A has three battery cells 2a having a maximum charging voltage of 4.2V, for example, when the number of times of charging is a, the target voltage for properly charging the battery set 2A It is determined that the value is 12.6 V (4.2 V / cell × 3 cells), the target current value is I1 (for example, 6 A) (FIG. 5), the target voltage value is 12.6 V, and the target current value is I1 (6 A ).

  In order to set the target voltage value to 12.6 V, the digital signal [0000110100] (corresponding to decimal number 52) may be output from the digital communication port 53 to the voltage reference value output unit 9. In order to set the target current value to I1 (6A), the digital signal [1111101000] (corresponding to decimal number 1000) may be output from the digital communication port 53 to the current reference value output unit 8.

  Note that the charging times a to d shown in FIG. 5 satisfy a <b <c <d. Moreover, ab of the frequency | count of charging of FIG. 5 means more than a times and less than b times. The same applies to b to c and c to d.

  In the present embodiment, the maximum charging voltage value of the battery cell 2a constituting the battery set 2A is 4.2V, the number of cells is 3, and the number of times of charging is a. When the number of times of charging is overlapped with the number of times a, the target voltage value is set to a voltage value Xa1 lower than 12.6V when the number of times of charging is a in order to suppress the progress of the deterioration of the secondary battery. To do. The target current value is also set to a current value that is Ya1 lower than I1. When the number of times of charging is further increased and the number of times of charging reaches c or more and less than d, the target voltage value is set to a voltage lower than Xa2 (Xa2> Xa1) than 12.6 V in order to suppress the progress of deterioration of the secondary battery. Set to value. The target current value is also set to a current value lower by Ya2 (Ya2> Ya1) than I1. In the same manner, the target voltage value and the target current value are decreased stepwise as the number of times of charging is repeated. Here, Xan and Yan (n is 1, 2, 3...) Are values appropriately determined from the maximum charging voltage value and allowable current value of the secondary battery. For example, Xa1 is 0.1 V and Xa2 is 0. .2V, Ya1 may be 0.1A, Ya2 may be 0.2A, Xa2 may be 0.25V, Ya2 may be 0.25A, and can be set as appropriate.

  Further, when the maximum charging voltage value of the battery cell 2a constituting the battery set 2A based on the battery information is 4.35V, the number of cells is 3, and the number of times of charging is a comparatively shallow number of times of a to less than b, 3 cells × 4.35V = 13.05V is set as the target voltage value. The target current value is I1. When the number of times of charging is more than b and less than c, the target voltage value is set to a voltage value Xb1 lower than 13.05 V in order to suppress the progress of deterioration of the secondary battery. The target current value is also set to a current value lower by Yb1 than I1. Further, when the number of times of charging is repeated and the number of times reaches c or more and less than d, the target current value is a voltage value lower than 13.05V by Xb2 (Xb2> Xb1) in order to suppress the progress of deterioration of the secondary battery. Set to. Further, the target current value is also set to a current value lower by Yb1 (Yb2> Yb1) than I1. Similarly, the target current value and the target current value are decreased each time the number of times is repeated. Here, Xbn and Ybn are values appropriately determined from the maximum charging voltage value and the allowable current value of the secondary battery, similarly to Xan and Yan.

  Further, when the maximum charging voltage value of the battery cell 2a constituting the battery set 2A based on the battery information is 4.5V, the number of cells is 3 cells, and the number of charging times is a comparatively shallow number of times of a to less than b, 3 cells × The target current value is 4.5 V = 13.5 V. The target current value is I1. When the number of times of charging is more than b and less than c, the target current value is set to a voltage value lower by Xc1 than 13.5 V in order to suppress the progress of deterioration of the secondary battery. The target current value is also set to a current value lower by Yc1 than I1. When the number of times of charging is further increased and the number of times reaches c or more and less than d, the target current value is set to a voltage value lower than 13.5 V by Xc2 (Xc2> Xc1) in order to further suppress the deterioration of the battery. . The target current value is also set to a current value lower than Y1 by Yc1 (Yc2> Yc1). Similarly, the target current value and the target current value are decreased each time the number of times is repeated. In addition, when the number of battery cells 2a constituting the battery set 2A according to the battery information is 4, 5, 7, 7, or 10 cells, the target current value per cell and the number of times of charging are similarly set. Determine the voltage value.

  In the present embodiment, the maximum charge voltage value and the number of cells of the battery cell 2a constituting the battery set 2A are transmitted from the battery pack 2 and the charging device 300 determines the information. Battery information may be determined. In the present embodiment, the charging-side microcomputer 50 determines the target voltage value and the target current value based on the battery information transmitted from the battery pack 2, but the information transmitted from the battery pack 2 is the battery information. Alternatively, the target voltage value and the target current value based on the battery information may be used. In this case, the charging device sets the transmitted target voltage value and target current value as they are.

  Charging is started after the target voltage value and target current value are set in step 405 (step 406). To start charging, a high signal is output from the port connected to the FET 4b in the first output unit 51a of the charging side microcomputer 50, and the PWM control IC 23 is activated. At the same time as charging is started, a charging start signal is output to the battery pack 2 via the information communication port 2g. Further, when charging is started, the display circuit 80 is lit in orange to indicate that charging is in progress (step 407). In order to turn on the display circuit 80 in orange, the LED 81 is lit in orange by outputting a high signal from the port connected to the resistor 82 and the port connected to the resistor 83 in the first output unit 51a.

  In the constant current control section, the battery set 2A is charged with the target current value I1. Thereafter, when the voltage of the battery group 2A reaches the set target voltage value, the process proceeds to the constant voltage control section, and charging is continued while maintaining the charging voltage at the target voltage value. In the constant voltage control section, it is determined whether or not the charging current is equal to or lower than the end current value (step 408). If it is determined in step 408 that the charging current is not equal to or less than the end current value, step 408 is repeated until the charging current becomes equal to or less than the end current value, and charging is continued. If it is determined that the charging current is equal to or less than the termination current value, the charging is terminated (S409). To end the charging, a low signal is output from the port connected to the FET 4b in the first output unit 51a of the charging side microcomputer 50, and the PWM control IC 23 is stopped.

  When the charging is completed, a charging end signal is output to the battery pack 2. When the charging end signal is input, the battery pack 2 updates the number of times of charging and stores it in the battery side memory 2e. The number of times of charging is used for determination of the degree of deterioration of the battery cell 2a during the subsequent charging. When charging is completed, the display circuit 80 is lit in green to indicate that charging is complete (step 410). To turn on the display circuit 80 in step 410 in green, the LED 81 is lit in green by outputting a high signal from the port connected to the resistor 83 in the first output unit 51a.

  After the charging is finished and the display circuit 80 is lit in green, it is determined whether or not the battery pack 2 is detached from the charging device 300 (step 411). When it is determined that the battery pack 2 is not detached from the charging device 300, step 218 is repeated, and the state where the display circuit 80 is lit in green is maintained. On the other hand, when it is determined that the battery pack 2 is detached from the charging device 300, the process returns to step 401, and the display circuit 80 is lit in red indicating a standby state before charging. Then, steps 401 and 402 are repeated until the battery pack 2 is mounted again, and the charging standby state is continued.

  Thus, in the present embodiment, a value obtained by multiplying the maximum charge voltage value of the secondary battery constituting the battery set by the number of cells of the secondary battery is set as a reference target voltage value, and the number of times of charging is further considered. Then, a target voltage value for properly charging the battery set is determined by subtracting a predetermined value corresponding to the number of times of charging from the reference target voltage value serving as the reference. In addition, the target current value is determined by gradually subtracting a predetermined value corresponding to the number of times of charging from the reference current value to determine a target current value for properly charging the battery set. For this reason, the target voltage value and the target current value decrease stepwise as the number of times of charging increases and deterioration progresses, and it is possible to optimally charge according to the characteristics of the secondary battery connected to the charging device. In addition to being able to do so, the progress of deterioration of the secondary battery can be suppressed and the secondary battery can have a long life.

  Further, like the charging device described in Patent Document 1, a configuration in which an identification element (for example, an identification resistor) provided in a battery pack is detected by a charger side microcomputer, that is, a configuration in which a battery type is determined in an analog manner is included. It can also be left. In this case, if an identification terminal different from the communication port 2g is provided, the charging-side microcomputer can determine information from the identification resistance of the battery pack. Furthermore, if a digital signal corresponding to the identification resistance is stored, the charging side microcomputer can determine the type of the battery pack from the identification resistance and set the reference target voltage value and the target current value based on the corresponding digital signal. Even when an existing battery pack is connected, it can be optimally charged.

  Next, a charging apparatus 500 according to a third embodiment of the present invention will be described with reference to FIGS. Similarly, the battery pack 502 connected to the charging device 500 will also be described. Hereinafter, in the charging apparatus 500, the same configuration as that of the charging apparatus 1 is denoted by the same reference numeral, description thereof is omitted, and only the configuration and control different from the charging apparatus 1 will be described. Further, in the battery pack 502, the same components as those of the battery pack 2 are denoted by the same reference numerals, description thereof is omitted, and only configurations and controls different from those of the battery pack 2 are described. FIG. 7 is a circuit diagram including a block diagram illustrating a configuration of a circuit inside charging device 500 and a circuit inside battery pack 502 attached to charging device 500.

  First, the battery pack 502 will be described. As shown in FIG. 7, the battery pack 502 includes a battery-side memory 502e.

  The battery side memory 502e stores battery information. Specifically, the battery-side memory 502e stores a battery type (type of the battery set 2A) and history information as battery information. The battery type is a classification based on the characteristics of the battery group 2A. The charging device 500 discriminates the battery type at the time of charging, so that characteristic information of the battery set 2A to be considered when charging, for example, the number of cells of the battery cell 2a constituting the battery set 2A, connection configuration (series) Number, parallel number), maximum charging voltage value of battery cell 2a (voltage per cell), target voltage value for properly charging the entire battery set 2A, allowable current value at the time of charging, judgment criterion for terminating charging It is possible to obtain information such as an end current value. The history information is information related to the charge / discharge history such as the number of times of charging, the number of times of discharging, the number of abnormal signals, and the like.

  Next, the charging apparatus 500 will be described. As shown in FIG. 7, the charging device 500 includes a charging side microcomputer 550, a current reference value output circuit 508, and a voltage reference value output circuit 509. The charging device 500 is configured to be connectable to a battery pack 502 and a plurality of types of battery packs having different battery types from the battery pack 502, and the battery pack 2A (battery cell 2a) is connected to the battery pack 502 in a state where the battery pack 502 is connected. Charge by constant voltage charge control. In the constant voltage control section in charging apparatus 500, the charging voltage is maintained at the target voltage value (constant voltage value) by appropriately changing the target current value and changing the charging current.

  The charging side microcomputer 550 has a digital communication port 553, a PWM signal output port 555, and a storage unit 556. The charging-side microcomputer 550 processes various input signals, and outputs various signals based on the results from the first output unit 51a, the digital communication port 553, and the PWM signal output port 555, and controls the operation of the charging device 500. To do.

  The digital communication port 553 is connected to the information communication port 2g of the battery pack 502, and the battery information stored in the battery-side memory 502e of the battery pack 502 in a state where the charging device 500 and the battery pack 502 are connected. Receive. The digital communication port 553 and the charging side microcomputer are examples of the information acquisition means of the present invention.

  The PWM signal output port 555 is connected to the current reference value output circuit 508 and is a port that outputs a PWM signal (hereinafter, a setting PWM signal) for setting a target current value. The charging-side microcomputer 550 sets a target current value by outputting a setting PWM signal from the PWM signal output port 555 to the charging current control circuit 60 via the current reference value output circuit 508. The charging side microcomputer 550 is configured to be able to change the duty ratio of the setting PWM signal, and changes the target current value by changing the duty ratio.

  The storage unit 556 stores a control program necessary for charging, various threshold values, a battery type table, tables shown in FIGS. 12 to 16 for determining a target current value and a target voltage value, and the like. . The battery type table is a table in which the battery type and the characteristic information of the battery set included in the battery type are described in a one-to-one relationship, and describes all the battery types of the battery pack that can be connected to the charging device 500. . It is a table which shows the characteristic information of the battery group corresponding to the said multiple types of battery types, respectively. That is, by comparing the battery type table with the battery type of the battery pack to be charged, the characteristic information of the battery set that the battery pack has can be specified. In addition, the storage unit 556 stores a comparison reference bit value used as a voltage threshold when determining whether or not the charging voltage has reached the target voltage value. The comparison reference bit value in the present embodiment is a value corresponding to the maximum charging voltage value of the battery set 2A as a whole, that is, 16.8 V (4.2 V / cell × 4 cells). The tables shown in FIGS. 12 to 16 will be described later.

  Here, a method of storing the comparison reference bit value in the storage unit 556 will be described with reference to FIG. FIG. 8 is a diagram illustrating a connection between the charging device 500 and the voltage output device S when the comparison reference bit value is stored. As shown in FIG. 8, the voltage output device S is connected to the voltage input unit 7c of the battery voltage detection circuit 7 at the time of manufacture, and the comparison reference voltage 16 corresponding to the comparison reference bit value is output from the voltage output device S. .8V is output. The voltage output device S is a device that can output a very accurate voltage used for calibration of a meter. For example, it is a device that can output the accuracy required when charging a lithium ion battery that requires high-accuracy voltage control.

  The comparison reference voltage output from the voltage output device S is divided by the resistors 7 a and 7 b and input to the A / D input port 52. Thereafter, the signal is converted into a digital signal by the A / D input port 52 and stored in the storage unit 556 as a bit value (comparison reference bit value). That is, the storage unit 556 includes the comparison reference voltage 16.8V input to the voltage input unit 7c, including variations due to the individual resistance values of the resistors 7a and 7b and the conversion error of the A / D input port 52. Are stored as comparison reference bit values. For this reason, although the comparison reference bit value stored in the storage unit 556 is different for each individual charging device 500 due to the variation by the individual, the bit value stored in each charging device 500 is very accurate 16. 8V is indicated. In this embodiment, the comparison reference voltage is set to 16.8 V, which is a value obtained by multiplying the maximum charging voltage per cell by 4 cells, but is not limited to this, and the life of the battery cell (secondary battery) is increased. Considering importance, it may be 16.7 V, which is slightly lower than 16.8 V, and 21.0 V (4.2 V / cell × 5 cells), etc., assuming that the battery set has 5 battery cells. Alternatively, 1V may be simply stored, and a desired voltage threshold value may be calculated from a bit value indicating accurate 1V. The comparison reference voltage or the comparison reference bit value is an example of the external voltage value of the present invention. The storage unit 556 is an example of the voltage storage unit of the present invention.

  Lithium ion batteries are generally charged at the maximum charging voltage (in this embodiment, 4.2 V per cell). When the charging voltage exceeds the maximum charging voltage, the battery is overcharged and the battery cell deteriorates. Or, if the possibility of failure increases and the charging voltage falls below the maximum charging voltage, the battery capacity is low because the battery capacity is low after charging or the charging time for charging to the specified battery capacity becomes long. Cannot be used to the maximum. Thus, in charging a lithium ion battery, it is important to match the charging voltage with the maximum charging voltage, and high accuracy is required for comparison (monitoring) between the charging voltage and the maximum charging voltage. In this regard, in the charging device 500, in order to determine whether or not the charging voltage has reached the target voltage value using a comparison reference bit value corresponding to a very accurate comparison reference voltage, that is, with high accuracy, The possibility of deterioration or failure of the battery cell can be reduced, and the performance of the battery cell can be utilized to the maximum.

  The current reference value output circuit 508 is a CR circuit having a resistor 508a and a capacitor 508b. The current reference value output circuit 508 smoothes the setting PWM signal output from the PWM signal output port 555 and supplies it to the charging current control circuit 60 as a comparison voltage corresponding to the target current value (hereinafter referred to as a smoothing comparison voltage). Output. The magnitude of the smoothing comparison voltage is determined by the time constant determined by the resistor 508a and the capacitor 508b and the duty ratio of the setting PWM signal. That is, since the time constant is determined at the time of manufacture, the magnitude of the smoothing comparison voltage can be changed by changing the duty ratio of the setting PWM signal output from the PWM signal output port 555 by the charging-side microcomputer 550, The target current value can be changed. The current reference value output circuit 50 is an example of the smoothing circuit of the present invention. The charging side microcomputer 550 and the current reference value output circuit 50 are examples of the target current value setting means of the present invention.

  Here, referring to FIGS. 8, 9A and 9B, the duty ratio of the setting PWM signal output from the PWM signal output port 555 and the smooth comparison output from the current reference value output circuit 508 The working voltage will be described. 9A and 9B show the setting PWM signal output from the PWM signal output port 555, and the right diagrams in FIGS. 9A and 9B show The smoothing comparison voltage output from the current reference value output circuit 508 is shown. 9A shows a case where the duty ratio of the setting PWM signal is 75%, and FIG. 9B shows a case where the duty ratio is 25%.

  As shown in FIG. 8, FIG. 9A and FIG. 9B, the setting PWM signal output from the PWM signal output port 555 is a pulse waveform, and is smoothed and compared by the current reference value output circuit 508. It is output to the charging current control circuit 60 as a working voltage. Also, as shown in FIGS. 9A and 9B, the duty ratio of the setting PWM signal and the magnitude of the smoothing comparison voltage are substantially proportional, and the duty ratio of the setting PWM signal is 75. The smoothing comparison voltage in the case of% is larger than the smoothing comparison voltage in the case of the duty ratio of 25%. In other words, the duty ratio of the setting PWM signal and the target current value are substantially proportional, and the target current value when the duty ratio of the setting PWM signal is 75% is more than the target current value when the duty ratio is 25%. Is also big. In the present embodiment, the duty ratio of the setting PWM signal can be changed in the range of 0 to 100%, and the smoothing comparison voltage is 0 to 5 V by changing the duty ratio in the range of 0 to 100%. The target current value can be set within a range of 1 to 10 A. The correspondence relationship between the changeable range of the duty ratio of the setting PWM signal and the settable target current value range is not limited to this, taking into consideration the performance of the charging device, the characteristics of the connected battery pack, and the like. What is necessary is just to determine suitably. Moreover, since the target current value is also affected by the power supply capacity, it is not necessary to limit it to the range of 1 to 10A.

  Thus, in the present embodiment, the target current value can be set steplessly in the range of 1 to 10 A by changing the duty ratio of the setting PWM signal, so that each battery set having different battery types, for example, The desired current value is set as a target current value for a battery set having a desired current value of 6A, a battery set of 5.8A, a battery set of 3.2A, a battery set of 2.5A, etc. Can do. That is, since the target current value can be changed flexibly, an appropriate target current value can be set for a plurality of types of battery packs having different battery types. Thereby, a battery set can be charged quickly and reliably, and the performance of each battery set can be utilized to the maximum extent.

  The voltage reference value output circuit 509 is a circuit for setting a potential difference between the positive terminal 1 a and the negative terminal 1 b until the battery pack 502 is connected to the charging device 500. The voltage reference value output circuit 509 has resistors 509a and 509b, divides Vcc using the resistors 509a and 509b, and outputs the divided voltage by the charge voltage control circuit 70 to set the pre-charge voltage. . The pre-charge voltage in the present embodiment is 23V.

  Next, an example of charging control of the charging device 500 according to the third embodiment of the present invention will be described with reference to the flowcharts of FIGS. 10 and 11.

  First, when AC power supply 90 and charging device 500 are connected, charging-side microcomputer 550 starts its operation, and in step 601, display circuit 80 is lit in red to indicate that it is in a charging standby state before charging. Next, in step 602, it is determined whether or not the battery pack 502 is mounted on the charging device 500. If it is determined in step 602 that the battery pack 2 is not mounted on the charging device 1, steps 601 and 602 are repeated until the battery pack 502 is mounted on the charging device 500, and the charging standby state is continued.

  On the other hand, if it is determined in step 602 that the battery pack 502 is mounted on the charging device 500 (step 602: Yes), the type of battery is determined in step 603. In step 603, the charging side microcomputer 550 communicates with the battery side microcomputer 2d via the information communication port 2g, and determines the battery type by acquiring battery information stored in the battery side memory 502e of the battery pack 502. To do. The charging side microcomputer 550 discriminates the battery type and collates it with the information stored in the storage unit 556, so that the maximum charging voltage value per cell of the battery cell 2a of the battery set 2A, the number of cells, the connection configuration, It is possible to specify a target current value, an allowable current value, an end current value, and the like appropriate for charging.

  Next, in step 604, communication is performed with the battery pack 502 via the information communication port 2g, and the battery temperature of the battery cell 2a (battery set 2A) detected by the temperature sensing element 2f of the battery pack 502 is acquired. Thereafter, in step 605, the charge / discharge history of the battery information stored in the battery-side memory 502e, that is, the number of times of charging and discharging is obtained.

  Next, in step 606, a target current value in the constant current control section is determined. Determination of the target current value in the constant current control section is performed based on the allowable current value and the connection configuration of the battery cells among the characteristics specified from the battery type. Specifically, it is determined according to a target current value determination table based on the connection configuration shown in FIG. As shown in FIG. 12, when the connection configuration of the battery cells 2a of the battery pack 502 is 1 (parallel number 1), it is determined as I1, and when 2 connections (parallel number 2) is determined as I2. . When the connection configuration of the battery cells is double, it is possible to simply tolerate twice the current as compared with the case where the battery cells are single, so the value of I2 is set to a value that is simply twice the value of I1. ing. In the present embodiment, I1 is set to 6A, which is the allowable current value of battery cell 2a, and I2 is set to 12A, which is twice I1.

  In the present embodiment, the target current value in the constant current control section is determined based on the allowable current value and the connection configuration. For example, the target current value is determined based on the battery temperature shown in FIG. You may decide according to a table. In this case, when the battery temperature is a low temperature of A ° C. or lower, the influence of the deterioration of the battery is taken into consideration, and the target current value I3 is set to a relatively small value. When the target current value is set to a large value I4 and the temperature is higher than B ° C., which is a high temperature state, the target current value is set to a medium target value I5 in consideration of the effect of battery deterioration (I3 <I5 <I4). . However, the determination of the target current value in the constant current control section is not limited to that described above, and the target current value may be determined in consideration of the allowable current value of the battery cell, the connection configuration, and the battery temperature. You may determine suitably according to a battery kind, a battery state (battery temperature, battery voltage, etc.) and charging / discharging log | history.

  After determining the target current value in the constant current control section, in step 607, charging is started. Charging is started from the constant current control section. To start charging, a high signal is output from the port connected to the FET 4b in the first output unit 51a of the charging side microcomputer 50, and the PWM control IC 23 is activated. In step 608, the display circuit 80 is lit in orange to indicate that charging is in progress.

  Next, in step 609, in order to set the target current value determined in step 606, the setting PWM signal is output from the PWM signal output port 555 as described above. In this case, the PWM signal output port 555 outputs a PWM signal for setting a duty ratio corresponding to the target current value determined in step 606.

  Next, in step 610, the battery temperature is monitored even during charging to reduce deterioration or failure of the battery cell 2a during charging. When the battery cell 2a exceeds a predetermined temperature during charging and becomes a high temperature state, the secondary battery 2a is in an abnormal state and may cause deterioration or failure. Therefore, in step 610, the battery temperature is monitored during charging. Shall. If the battery temperature exceeds a predetermined temperature as a result of monitoring, charging is stopped.

  Next, in step 611, it is determined whether or not the battery voltage (charging voltage) has reached a target voltage value. The determination is performed by determining a target voltage value and comparing the target voltage value with the battery voltage. Hereinafter, determination of the target voltage value and comparison between the target voltage value and the battery voltage will be described.

  The determination of the target voltage value is performed only once when the process of step 611 is performed for the first time in the charge control, and is performed based on the number of battery cells 2a among the characteristics of the battery set specified from the battery type. Specifically, it is determined according to the target voltage value determination table based on the number of cells shown in FIG. As shown in FIG. 14, when the number of battery cells 2a of the battery pack 502 is 4, X is determined as X, and when the number is 5 cells, X × (5/4) is determined. In the present embodiment, X is 16.8V (comparison reference voltage). The charging side microcomputer 550 is an example of a target voltage value setting unit.

  In the present embodiment, the target voltage value is determined based on the number of battery cells 2a. However, in recent years, the capacity of the battery has been increased, and only the battery cell having the maximum charging voltage of 4.2V as described above. However, in view of the fact that battery cells with a maximum charging voltage of 4.3 V have been developed, the target voltage value is determined according to the target voltage value determination table based on the maximum charging voltage shown in FIG. You may do it. In this case, if the maximum charging voltage is 4.2V, the target voltage value is determined to be X (16.8V), and if the maximum charging voltage is 4.3V, the target voltage value is X + Y1 (Y1 is per cell). A value corresponding to 0.1V).

  In addition, the battery cell deteriorates due to repeated charge / discharge cycles, and the battery capacity decreases. However, when the charge voltage is lowered, the battery cell is charged with less burden, and the deterioration state can be suppressed. For example, the target voltage value may be determined according to a target voltage value determination table based on the number of times of charging / discharging shown in FIG. In this case, the target voltage value is determined as X when the number of times of charging / discharging is A or less, which is relatively shallow, and the target voltage value is X− smaller than X when the number of times of charging / discharging is A to B. When it is determined as Y2 and the number of times of charging / discharging is B times or more, the degree of deterioration is relatively advanced, and it is necessary to suppress the deterioration more. Therefore, the target voltage value is set to be lower than XY2. The smaller X−Y3 (Y2 <Y3) is determined. As described above, the determination of the target voltage value in step 611 is appropriately set for X (comparison reference voltage) according to the battery type and the battery state (battery temperature, etc.). Further, the determination of the target voltage value is not limited to the above, and it may be determined based on only the number of times of charging or the number of times of discharging. Y1, Y2, and Y3 are examples of the predetermined value of the present invention.

  The comparison between the target voltage value and the battery voltage (charge voltage) is performed based on the comparison reference bit value stored in the storage unit 556 described above. For example, when the target voltage value is determined to be X in step 611, the bit value corresponding to X is the comparison reference bit value stored in the storage unit 556 at the time of manufacture, and the bit value corresponding to the battery voltage is This is a bit value (hereinafter referred to as a detection bit value) corresponding to the battery voltage input to the battery voltage detection circuit 7 and digitally converted at the A / D input port 52, and by comparing the comparison reference bit value with the detection bit value. It is determined whether or not the battery voltage has reached a target voltage value. As described above, it is possible to determine with high accuracy whether or not the battery voltage has reached the target voltage value by comparing the comparison reference bit value indicating 16.8V very accurately with the detection bit value. .

  For example, when the target voltage value is determined to be X + Y1, the arithmetic unit of the charging side microcomputer 550 calculates the bit value corresponding to X + Y1 based on the comparison reference bit value, and detects the calculated bit value. It is determined whether or not the battery voltage has reached the target voltage value by comparing the bit value. The same applies when the target voltage value is determined as XY2, XY3.

  Now, the description returns to the control flow. If it is determined in step 611 that the battery voltage has not reached the target voltage value (step 611: No), the process returns to step 209, the battery voltage reaches the target voltage value, and step 609 is performed until an affirmative determination is made in step 611. Repeat 610 and 611.

  On the other hand, when the battery voltage has reached the target voltage value in step 611 (step: Yes), in step 612, control is performed so as to shift to the constant voltage control section and maintain the battery voltage at the target voltage value. In the present embodiment, the battery voltage is lowered by changing the target current value to a value smaller than the value at the time of step 612. Control for maintaining the battery voltage at the target voltage value will be described later. Next, in step 613, as in step 610, the battery temperature is monitored. If the battery temperature exceeds a predetermined temperature as a result of monitoring, charging is stopped.

  Next, in step 614, it is determined whether or not the battery is fully charged. Whether or not the battery is fully charged is determined based on whether or not the current value detected by taking the output of the operational amplifier 61 into the A / D input port 52, that is, the charging current is equal to or less than the end current value specified by the battery information. Judge. When it is determined that the battery is not fully charged (step 614: No), the battery voltage is controlled to be maintained at the target voltage value while repeating steps 612, 613, and 614.

  The control for maintaining the battery voltage at the target voltage value determines whether or not the battery voltage has reached the target voltage value every time it passes through step 612 while repeating steps 612 to 614. The target current value is changed to a value smaller than the target current value in the constant current control section. Specifically, when the target current value is lowered, the battery voltage once drops, so charging is continued with the lowered value (repetition of steps 612 to 614). When the battery voltage continues to reach the target voltage value again, the target current value is set to a smaller value (step 612), and the battery voltage is lowered to continue charging. In this way, control is performed so that the battery voltage is maintained at the target voltage value while the battery voltage reaches the target voltage value, the target current value decreases, and the battery voltage decreases repeatedly.

  On the other hand, if it is determined that the battery is fully charged (step 614: Yes), charging is terminated in step 615. When charging is completed, a charging end signal is output to the battery pack 502. When the charging end signal is input, the battery pack 502 updates the number of times of charging and stores it in the battery side memory 502e. The number of times of charging is used for determination of the degree of deterioration of the battery cell 2a during the subsequent charging. When the charging is finished, in step 616, the display circuit 80 is lit in green to indicate that the charging is finished.

  After the charging is completed and the display circuit 80 is lit in green, it is determined in step 617 whether or not the battery pack 2 has been detached from the charging device 1. If it is determined that the battery pack 2 is not detached from the charging device 500, step 617 is repeated, and the state where the display circuit 80 is lit in green is maintained. On the other hand, when it is determined that the battery pack 502 is detached from the charging device 500, the process returns to step 601, and the display circuit 80 is lit in red indicating the standby state before charging. Steps 601 and 602 are repeated until the battery pack 502 is mounted again, and the charging standby state is continued.

  Next, a charging current and a charging voltage when the battery pack 502 is charged in the charging device 500 according to the flowcharts of FIGS. 10 and 11 will be described with reference to FIG. FIG. 17 is a diagram illustrating temporal changes in the charging current and the charging voltage in the charging control by the charging apparatus 500, and illustrates a case where the target current value is set to X. FIG.

  As shown in FIG. 17, charging is started at time t0 (corresponding to step 607). After charging is started at time t0, it is a constant current control section. In the constant current control section, the charging current is determined in step 606 and controlled to be maintained at the target current value set in step 609 (corresponding to repetition of steps 609 to 611). The charging voltage (battery voltage) increases with time after the constant current control is started at time t0, and reaches X, which is the target voltage value, at time t1. After time t1 when the target voltage value X is reached at time t1, the process proceeds to a constant voltage control section (corresponding to Yes in Step 611), and the charging voltage (battery voltage) is controlled to be maintained at X. The charging current is decreasing (corresponding to repetition of steps 612 to 614). Thereafter, at time t2, the charging current becomes equal to or less than the termination current value (corresponding to Step 614: Yes), and charging is completed (corresponding to Step 615). When the target voltage values are set to X + Y1, XY2, and XY3, the charging voltage (battery voltage) increases to the respective broken lines shown in FIG. 17 corresponding to the respective target voltage values. After that, the process proceeds to the constant voltage charge control section.

  As described above, the charging apparatus 500 according to the third embodiment of the present invention uses the charging current control circuit 60 that controls the charging current to become the target current value, and the target current value using the setting PWM signal. Since the charging side microcomputer 550 and the current reference value output circuit 508 are set, the target current value can be set by outputting the setting PWM signal.

  Further, since the charging side microcomputer 550 and the current reference value output circuit 508 change the target current value by changing the duty ratio of the setting PWM signal, the target current value can be set to various values in a stepless manner. it can. For this reason, a wide variety of battery sets can be reliably and quickly charged.

  In addition, since the current reference value output circuit 508 that smoothes the setting PWM signal is provided and the setting PWM signal can be smoothed, the target current value can be set accurately.

  In addition, the charging device 500 includes a voltage input unit 7c capable of inputting an external voltage, a storage unit 556 that stores a comparison reference voltage (comparison reference bit value) input to the voltage input unit 7c, and a storage unit 556. A charging-side microcomputer 550 that sets a target voltage value based on the stored comparison reference voltage (comparison reference bit value), and the charging-side microcomputer 550 charges the charging voltage after the charging voltage reaches the target voltage value. Is maintained at the stored comparison reference voltage (comparison reference bit value). For this reason, it is possible to accurately determine whether or not the charging voltage has reached the target voltage value by using a highly accurate comparison reference voltage (comparison reference bit value). Failure can be suppressed and the performance of the battery cell 2a can be utilized to the maximum.

  Further, since the charging side microcomputer 550 sets the stored comparison reference voltage (comparison reference bit value) itself as the target voltage value, the charging voltage is set to the target voltage value by using a highly accurate external voltage value. It is possible to more accurately determine whether or not the battery cell 2a has been reached, to further suppress the deterioration or failure of the battery cell 2a, and to maximize the performance of the battery cell 2a.

  Moreover, it further includes a charging-side microcomputer 550 and a digital communication port 553 that acquire battery information related to the battery set 2A, and the charging-side microcomputer 550 is connected to the charging device 500 in order to set a target current value based on the battery information. An appropriate target current value can be set for the battery set 2A, and deterioration or failure of the battery cell 2a of the battery set 2A can be further suppressed.

  Further, it further includes a charging side microcomputer 550 and a digital communication port 553 for acquiring battery information related to the battery set 2A, and the charging side microcomputer 550 stores a comparison reference voltage (comparison reference bit value), that is, X based on the battery information. In order to set the value obtained by adding Y1 to the target voltage value, an appropriate target voltage value can be set for the battery set 2A connected to the charging device 500, and the battery cell 2a included in the battery set 2A is deteriorated or Failure can be further suppressed.

  Further, it further includes a charging side microcomputer 550 and a digital communication port 553 for acquiring battery information related to the battery set 2A, and the charging side microcomputer 550 stores a comparison reference voltage (comparison reference bit value), that is, X based on the battery information. Since the value obtained by subtracting Y2 or Y3 from the battery is set as the target voltage value, an appropriate target voltage value can be set for the battery set 2A connected to the charging device 500, and the battery cell 2a of the battery set 2A is deteriorated. Or a failure can be suppressed more.

  Further, in the present embodiment, the battery information includes the battery type that is the type of the battery set 2A, so that charge control according to the battery type can be performed. For this reason, deterioration or failure of the battery cell 2a can be further suppressed, and the performance of the battery cell 2a can be utilized to the maximum.

  In the present embodiment, the battery information includes the battery temperature that is the temperature of the battery set 2A. For this reason, charge control according to the battery temperature, which is a factor that greatly affects the deterioration or failure of the battery cell, can be performed. For this reason, deterioration or failure of the battery cell 2a can be further suppressed, and the performance of the battery cell 2a can be utilized to the maximum.

  Further, in the present embodiment, since the battery information includes the number of times of charging or discharging, which is an index indicating the degree of deterioration of the battery cell 2a, it corresponds to the degree of deterioration of the battery cell 2a estimated from the number of times of charging or discharging. Charge control can be performed. For this reason, deterioration or failure of the battery cell 2a can be further suppressed, and the performance of the battery cell 2a can be utilized to the maximum.

  The charging device 500 includes a charging current control circuit 60 that controls the charging current to be a target current value, a charging-side microcomputer 550 that sets a target current value using a setting PWM signal that is a digital signal, and a current reference value output. Circuit 508, at least one of the charging voltage and the charging current can be controlled by a digital signal, and various types of control can be performed as compared with the charging device described in Patent Document 1. Further, the target current value can be set by the setting PWM signal.

  The charging device according to the present invention is not limited to the above-described embodiments, and various modifications are possible within the scope of the gist of the invention described in the claims.

  DESCRIPTION OF SYMBOLS 1,300,500 ... Charger 1a ... Positive terminal 1b ... Negative terminal 2 ... Battery pack 2A ... Battery set 2a ... Battery cell 2c ... Battery side power supply circuit 2d ... Battery side microcomputer 2e ... Battery side memory 2f ... Temperature sensing element 2g DESCRIPTION OF SYMBOLS ... Information communication port 3 ... Current detection resistor 4 ... Charge control signal transmission part 4a ... Photocoupler 5 ... Charge control signal transmission part 6 ... Switching power supply circuit 7 ... Battery voltage detection circuit 7c ... Voltage input part 8 ... Current reference value output part DESCRIPTION OF SYMBOLS 9 ... Voltage reference value output part 10 ... Rectification smoothing circuit 20 ... Switching circuit 30 ... Rectification smoothing circuit 40 ... Auxiliary power supply circuit 50, 550 ... Charge side microcomputer 51a ... Output part 52 ... Input port 53, 553 ... Digital communication port 60 ... Charge current control circuit 70 ... Charge voltage control circuit 80 ... Display circuit 90 ... AC power supply 508 ... Current base Quasi-value output circuit storage unit 556

Claims (33)

A charging device for charging a battery set having a secondary battery,
A charging device characterized in that at least one of a charging voltage and a charging current of the battery set is controlled by a digital signal. A reference value output unit for setting a reference value of at least one of the charging voltage and the charging current based on the digital signal;
The charging device according to claim 1, further comprising: a control unit that controls at least one of the charging voltage and the charging current based on the reference value. The reference value output unit includes a voltage reference value output unit that sets a voltage reference value of the charging voltage, and a current reference value output unit that sets a current reference value of the charging current,
The charging device according to claim 2, wherein the control unit controls the charging voltage and the charging current to be the corresponding reference values based on the digital signal. Charging means for charging the battery set;
The control unit
A charging voltage control unit that compares the detected charging voltage with the voltage reference value output from the voltage reference value output unit;
A charging current control unit that compares the detected charging current with the current reference value output from the current reference value output unit;
Have
4. The charging means is configured so that the charging voltage and the charging current become the corresponding reference values based on the comparison results from the charging voltage control unit and the charging current control unit. The charging device described in 1. Charging means for charging a battery set having one or more secondary batteries;
digital signal output means for outputting an n-bit digital signal;
In response to the digital signal output from the digital signal output means, target signal output means for outputting a target signal indicating a target voltage corresponding to the value of the digital signal from 2 ⁿ target voltages;
And a charging voltage control unit configured to control the charging voltage to be the target voltage based on the target signal. The battery set is housed in a battery pack,
6. The digital signal output means acquires battery information from the battery pack, and determines the value of the digital signal to be output to the target signal output means based on the battery information. Charging device.   The battery information includes at least one of a maximum charging voltage value of the secondary battery, the number of cells of the secondary battery constituting the battery set, history information regarding the number of times of charging the battery set, and characteristic information of the battery set. Information is included, The charging device of Claim 5 or 6 characterized by the above-mentioned. Charging means for charging a battery set having one or more secondary batteries;
digital signal output means for outputting an n-bit digital signal;
Reference value output means for outputting a reference value corresponding to the value of the digital signal from 2 ⁿ (n is an integer of 1 or more) reference values in response to the digital signal output from the digital signal output means When,
Target voltage value selection means for selecting one target voltage value from 2 ⁿ target voltage values corresponding to each of the 2 ⁿ reference values in a one-to-one relationship;
And a charging voltage control unit configured to control the charging voltage using the reference value so that a charging voltage value becomes the target voltage value corresponding to the reference value. The 2 ⁿ reference values are
A first reference value corresponding to a first target voltage value for charging a first battery set whose maximum charging voltage value of the secondary battery is a first value;
And a second reference value corresponding to a second target voltage value for charging a second battery set whose maximum charging voltage value of the secondary battery is a second value. Item 9. The charging device according to Item 8. The reference value output means is a D / A converter or a digital potentiometer having n-bit resolution and capable of outputting 2 ⁿ reference voltages.
The charging device according to claim 8 or 9, wherein the reference voltage is used as the reference value. The battery set is housed in a battery pack,
The battery pack includes storage means for storing information on the target voltage value for charging the battery set, and battery side communication means for communicating information on the target voltage value with the target voltage value selection means. ,
The charging device further includes charging-side communication means for communicating information on the target voltage value with the battery pack,
11. The charging device according to claim 8, wherein the target voltage value selection unit selects the target voltage value based on information related to the target voltage value. The battery set is housed in a battery pack,
The battery pack includes a storage unit that stores battery information related to the battery set, and a battery-side communication unit that communicates the battery information with the target voltage value selection unit.
The charging device further includes charging-side communication means for communicating the battery information with the battery pack,
The charging device according to any one of claims 8 to 10, wherein the target voltage value selection means selects the target voltage value based on the battery information. The battery information includes history information relating to charging history of the battery set, and characteristic information relating to characteristics of the battery set,
13. The charging apparatus according to claim 12, wherein the target voltage value selection unit selects the target voltage value based on the history information and the characteristic information.   The charging device according to claim 13, wherein the target voltage value selecting means selects the target voltage value having a lower value as the number of times of charging increases. Charging means for charging a battery set having one or more secondary batteries;
digital signal output means for outputting an n-bit digital signal;
Reference value output means for outputting a reference value corresponding to the value of the digital signal from 2 ⁿ (n is an integer of 1 or more) reference values in response to the digital signal output from the digital signal output means When,
And the target current value selecting means for selecting one of the target current value from among the 2 ⁿ pieces of target current values corresponding to each of the 2 ⁿ pieces of reference values,
A charging device comprising: charging current control means for controlling the charging current so that a charging current value becomes the target current value corresponding to the reference value using the reference value. The 2 ⁿ reference values are
A first reference value corresponding to a first target current value for charging the first battery set whose allowable current value is the first current value;
The second reference value corresponding to the second target current value for charging the second battery set whose allowable current value is the second current value, and the second reference value, Charging device. The reference value output means is a D / A converter or a digital potentiometer having n-bit resolution and capable of outputting 2 ⁿ reference voltages.
The charging device according to claim 15 or 16, wherein the reference voltage is used as the reference value. The battery set is housed in a battery pack,
The battery pack includes storage means for storing information on the target current value for charging the battery set, and battery side communication means for communicating information on the target current value with the target current value selection means. ,
The charging device further includes charging-side communication means for communicating information on the target current value with the battery pack,
The charging device according to any one of claims 15 to 17, wherein the target current value selection means selects the target current value based on information on the target current value. The battery set is housed in a battery pack,
The battery pack includes a storage unit that stores battery information related to the battery set, and a battery-side communication unit that communicates the battery information with the target current value selection unit.
The charging device further includes charging-side communication means for communicating the battery information with the battery pack,
The charging device according to any one of claims 15 to 17, wherein the target current value selection unit selects the target current value based on the battery information. The battery information includes history information relating to charging history of the battery set, and characteristic information relating to characteristics of the battery set,
The charging device according to claim 19, wherein the target current value selecting means selects the target current value based on the history information and the characteristic information.   21. The charging device according to claim 20, wherein the target current value selecting means selects a lower target current value as the number of times of charging increases. Charging current control means for controlling the charging current to be a target current value;
The charging device according to claim 1, further comprising: a target current value setting unit that sets the target current value using a PWM signal.   23. The charging device according to claim 22, wherein the target current value setting means changes the target current value by changing a duty ratio of the PWM signal.   24. The charging apparatus according to claim 22, wherein the target current value setting means includes a smoothing circuit that smoothes the PWM signal. A voltage input unit capable of inputting an external voltage;
Voltage storage means for storing an external voltage value input to the voltage input unit;
Further comprising target voltage value setting means for setting a target voltage value based on the external voltage value stored in the voltage storage means,
The target current value setting means changes the target current value so that the charge voltage is maintained at the stored external voltage value after the charge voltage reaches the target voltage value. The charging device according to any one of claims 22 to 24.   26. The charging device according to claim 25, wherein the target voltage value setting means sets the stored external voltage value as the target voltage value. Further comprising information acquisition means for acquiring battery information relating to the battery set;
27. The charging device according to claim 22, wherein the target current value setting unit sets the target current value based on the battery information. Further comprising information acquisition means for acquiring battery information relating to the battery set;
26. The charging device according to claim 25, wherein the target voltage value setting means sets, as the target voltage value, a value obtained by adding a predetermined value to the stored external voltage value based on the battery information. . Further comprising information acquisition means for acquiring battery information relating to the battery set;
The charging device according to claim 25, wherein the target voltage value setting means sets a value obtained by subtracting a predetermined value from the stored external voltage value as the target voltage value based on the battery information. .   30. The charging device according to claim 27, wherein the battery information includes a battery type that is a type of the battery set.   30. The charging device according to claim 27, wherein the battery information includes a battery temperature that is a temperature of the battery set.   30. The charging device according to claim 27, wherein the battery information includes the number of times of charging or discharging of the battery set. A charging device for charging a battery set having a secondary battery,
Charging current control means for controlling the charging current to be a target current value;
And a target current value setting means for setting the target current value using a PWM signal which is a digital signal.

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