JP2007267498A - Charger, charging system and electric apparatus - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a charger for efficiently charging a lithium ion secondary battery to shorten the charging time, and also to provide a charging system and an electric apparatus. <P>SOLUTION: The charger for charging a lithium ion secondary battery 31 of charging object by a constant current constant voltage charging system comprises: a DC power supply section 13 supplying power for charging the lithium ion secondary battery 31; a section 11 for measuring the voltage of the lithium ion secondary battery 31; a section 14 for measuring the current flowing through the lithium ion secondary battery 31; and a section 12 for measuring the voltage of the lithium ion secondary battery 31 at the voltage measuring section 11 by feeding a current of smaller current value than the charging current during charging operation from the DC power supply section 13 to the lithium ion secondary battery 31 at least during constant current charging operation or constant voltage charging operation, and for controlling the DC power supply section 13 to perform charging operation, based on the measurements. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a charging device for charging a lithium ion secondary battery. The present invention also relates to a charging system including the charging device and a secondary battery device of a lithium ion secondary battery, and an electric device in which the charging device is incorporated.

  In recent years, lithium ion secondary batteries have come to be used as driving power sources in various electric devices such as electric tools, electric razors, mobile phones, and notebook personal computers.

  FIG. 12 is a diagram illustrating charging characteristics of the lithium ion secondary battery. The horizontal axis in FIG. 12 represents the charge capacity in Ah units, the right vertical axis represents the battery voltage Vb in V units, and the left vertical axis represents the charge current Ic in A units. The solid line is the charging current Ic, and the alternate long and short dash line is the battery voltage Vb.

  When charging the lithium ion secondary battery, constant current charging is performed so that the current value Ix of the current (charging current) Ic flowing to the lithium ion secondary battery becomes a constant value. If the secondary battery continues to be charged with constant current charging, it is overcharged and the battery voltage Vb becomes abnormally high, resulting in deterioration. Therefore, the lithium ion secondary battery cannot be fully charged only by constant current charging. As shown in FIG. 12, the voltage value Ex of the voltage (battery voltage) Vb in the lithium ion secondary battery is set to a predetermined value. The constant current charging (a) is performed at a predetermined constant current value Icc until the voltage value (voltage threshold) Eth is reached, and after the voltage value Ex of the battery voltage Vb reaches the predetermined set voltage value Eth, lithium ion A constant voltage charge (b) is performed in which the charging current Ic flowing through the secondary battery is gradually decreased so that the voltage value Ex of the battery voltage Vb does not exceed a predetermined set voltage value Eth.

  FIG. 13 is a block diagram illustrating a configuration of a charging system according to the background art. FIGS. 13A and 13B show the first and second configurations of the charging system, respectively.

  Conventionally, a charging system 1001 for charging a lithium ion secondary battery by such a constant current-constant voltage charging method includes, for example, a lithium ion secondary battery device 1011 and a lithium ion battery as shown in FIG. And a charging device 1021 for charging the secondary battery device 1011.

  The lithium ion secondary battery device 1011 is inserted into a lithium ion secondary battery 1012 configured to include one or a plurality of lithium ion secondary battery cells, and a wire path through which a charging current Ic of the lithium ion secondary battery 1012 flows. The battery voltage Vb and the battery temperature Tb are obtained from the resistor 1013 and the lithium ion secondary battery 1012 and the battery current Ic of the lithium ion secondary battery 1012 is obtained from the voltage across the terminals of the resistor 1013 to obtain the lithium ion secondary battery. 1012 is configured to include a control unit 1014 that performs charge / discharge state monitoring for 1012 and outputs a monitoring result to the charging device 1021 via the connection terminal 1015.

  The charging device 1021 receives the monitoring result from the control unit 1014 of the lithium ion secondary battery device 1011 via the connection terminal 1024, and the constant current − based on the battery temperature Tb, the charging current Ic, and the battery voltage Vb of the monitoring result. The charging control unit 1022 charges the lithium ion secondary battery 1012 by a constant voltage charging method, and a functional block 1023 for realizing other functions other than charging of the charging device 1021.

  In the charging system 1001 having such a configuration, the charging control unit 1022 of the charging device 1021 receives the monitoring result from the control unit 1014 of the lithium ion secondary battery device 1011 via the connection terminals 1015 and 1024, and receives the monitoring result. The lithium ion secondary battery 1012 is charged by a constant current-constant voltage charging method based on the battery temperature Tb, the charging current Ic, and the battery voltage Vb.

  Note that the charging system 1001 of the type that measures the charging current Ic and the battery voltage Vb and monitors the charging / discharging state of the lithium ion secondary battery 1012 on the lithium ion secondary battery device 1011 side is a constant current-constant voltage. Although voltage charging control is also performed, for example, it is disclosed in Patent Document 1.

  For example, as illustrated in FIG. 13B, the charging system 1002 includes a lithium ion secondary battery device 1031 and a charging device 1041 that charges the lithium ion secondary battery device 1031.

  The lithium ion secondary battery device 1031 detects the temperature of the lithium ion secondary battery 1032 configured to include one or a plurality of lithium ion secondary battery cells, and the lithium ion secondary battery 1012, and connects the detection result to the connection terminal. And a thermistor 1033 that outputs to the charging device 1021 via the battery 1034.

  The charging device 1041 receives the detection result as the battery temperature Tb from the thermistor 1033 of the lithium ion secondary battery device 1031 via the connection terminal 1044, and from the electric wire path through which the charging current Ic to the lithium ion secondary battery device 1031 flows. The current I and the voltage E are measured as the charging current Ic and the battery voltage Vb, and the lithium ion secondary battery 1032 is charged by a constant current-constant voltage charging method based on the battery temperature Tb, the charging current Ic, and the battery voltage Vb. And a functional block 1043 for realizing other functions other than charging of the charging device 1041.

In the charging system 1002 having such a configuration, the charging control unit 1042 of the charging device 1041 receives the detection result as the battery temperature Tb from the thermistor 1033 of the lithium ion secondary battery device 1031 via the connection terminals 1034 and 1044. The current I and the voltage E are measured as the charging current Ic and the battery voltage Vb from the electric line through which the charging current Ic to the lithium ion secondary battery device 1031 flows, and based on the battery temperature Tb, the charging current Ic and the battery voltage Vb. Then, the lithium ion secondary battery 1032 is charged by a constant current-constant voltage charging method.
JP 2000-092737 A

  By the way, in the charging system 1001 of the type in which the charging current Ic and the battery voltage Vb are measured and the state of charging / discharging of the lithium ion secondary battery 1012 is monitored on the lithium ion secondary battery device 1011 side, the lithium ion secondary battery is used. Since the battery voltage Vb of 1012 is directly measured, the difference between the battery voltage Vb of the measurement result and the actual battery voltage Vb is small. Even if there is a voltage drop due to a circuit pattern between the control unit 1014 and the lithium ion secondary battery 1012 or manufacturing variations of the lithium ion secondary battery 1012, the control unit 1014 is incorporated in the lithium ion secondary battery device 1011. Therefore, since the battery voltage Vb of the measurement result can be corrected in consideration of these error factors in advance, the difference between the battery voltage Vb of the measurement result and the actual battery voltage Vb can be reduced. . Therefore, since this type of charging system 1001 can relatively accurately monitor the state of charging / discharging of the lithium ion secondary battery 1012, the battery voltage Vb of the lithium ion secondary battery 1012 is substantially set to the set voltage value. Constant current charging can be performed until Eth is reached, and thereafter constant voltage charging can be performed with a charging current Ic at which the battery voltage Vb does not substantially exceed the set voltage value Eth. Therefore, this type of charging system 1001 can efficiently charge the lithium ion secondary battery 1012 so as to shorten the charging time without deteriorating the lithium ion secondary battery 1012.

  However, since the control unit 1014 is provided in the lithium ion secondary battery device 1011, the control unit 1014 and its peripheral circuits, a drive power source, and the like are required. For this reason, this type of charging system 1001 increases the size and cost of the lithium ion secondary battery device 1011 and reduces the power consumption of the control unit 1014 (that is, the amount of power supplied by the lithium ion secondary battery device 1011 can be reduced). ) Etc.

  FIG. 14 is a diagram illustrating the charging characteristics of the lithium ion secondary battery when the charging / discharging state monitoring of the lithium ion secondary battery is performed on the charging device side. FIG. 14 (A) shows the charge capacity-battery voltage characteristics, the horizontal axis represents the charge capacity expressed in Ah units, and the vertical axis represents the battery voltage Vb expressed in V units. FIG. 14B shows time-charging current characteristics, the horizontal axis represents time shown in min (minutes), and the vertical axis shows charging current Ic shown in A units. The solid line indicates the characteristics of the actual lithium ion secondary battery, and the broken line indicates the battery voltage Vb and the charging current Ic measured on the charging device side.

  On the other hand, in the charging system 1002 of the type in which the charging current Ic and the battery voltage Vb are measured and the charging / discharging state monitoring of the lithium ion secondary battery 1032 is performed on the charging device 1041 side, these lithium ion secondary battery devices 1031 Problems such as an increase in size, cost, and power consumption of the control unit can be reduced.

However, in this type of charging system 1002, the contact resistance value varies depending on whether the contact state between the connection terminals 1044 and 1034 connecting the charging device 1041 and the lithium ion secondary battery 1032 is good, the lithium ion secondary battery. The battery voltage Vb measured on the charging device 1041 side and the actual battery voltage Vb as shown in FIG. 14A due to a voltage drop due to a circuit pattern in the device 1031 and manufacturing variations of the lithium ion secondary battery 1032 or the like. A relatively large error _VR0 occurs between the two. Therefore, in this type of charging system 1002, the charging capacity-battery voltage characteristic and time-charging current characteristic (broken line in the figure) based on the battery voltage Vb and the charging current Ic measured on the charging device 1041 side are actual lithium ions. It does not coincide with the characteristics of the secondary battery 1032 (solid line in the figure). As a result, this type of charging system 1002 charges the lithium ion secondary battery 1032 more efficiently than the type in which the state of charge / discharge of the lithium ion secondary battery 1032 is monitored on the lithium ion secondary battery 1032 side. The charging time is extended by time tr.

  The present invention has been made in view of the above circumstances, and can charge a lithium ion secondary battery efficiently so as to shorten the charging time even when the battery voltage is measured on the charging device side. An object is to provide an apparatus. And it aims at providing a charging system provided with this charging device and a lithium ion secondary battery, and an electric equipment incorporating this charging device.

  As a result of various studies, the present inventor has found that the above object is achieved by the present invention described below. That is, in one aspect according to the present invention, the lithium ion secondary battery to be charged is subjected to constant current charging until the battery voltage of the lithium ion secondary battery reaches a set voltage value. After the battery voltage reaches the set voltage value, the battery voltage of the lithium ion secondary battery does not substantially exceed the set voltage value until the charging current of the lithium ion secondary battery reaches the set current value. In a charging device that performs constant voltage charging with current, a power supply unit that supplies power for charging the lithium ion secondary battery, a voltage measurement unit that measures the voltage of the lithium ion secondary battery, and the lithium ion secondary battery A current measurement unit that measures a current flowing to the current source, and during charging of at least one of the constant current charging and the constant voltage charging, than a current value of a charging current during the charging The voltage measurement unit measures the voltage of the lithium ion secondary battery by flowing a current having a current value from the power supply unit to the lithium ion secondary battery, and the charging is performed based on the measurement result. And a control unit for controlling the power supply unit.

  In the above-described charging device, the power supply control unit supplies a current having a current value smaller than the current value of the charging current during the charging during at least one of the constant current charging and the constant voltage charging. The voltage measurement unit measures the voltage of the lithium ion secondary battery by flowing from the power supply unit to the lithium ion secondary battery, and controls the power supply unit to perform the charging using the measurement result as the battery voltage. It is characterized by doing.

  Further, in the above-described charging device, the power supply control unit may perform different first and different charging current values smaller than a current value of the charging current during the charging during at least one of the constant current charging and the constant voltage charging. The voltage measurement unit measures the first and second voltages of the lithium ion secondary battery by causing the first and second currents of the second current value to flow from the power supply unit to the lithium ion secondary battery, and the first Controlling the power supply unit to perform the charging by correcting the set voltage value based on the first and second current values of the first and second currents and the first and second voltage values of the measurement result. Features.

  Furthermore, the above-described charging devices further include a set voltage correction unit that corrects the set voltage value according to a battery temperature of the lithium ion secondary battery.

  And in another one aspect | mode which concerns on this invention, in the charging system provided with a secondary battery apparatus provided with a lithium ion secondary battery, and the charging device which charges the said lithium ion secondary battery, the said charging apparatus is these above-mentioned. It is any one of these.

  In another embodiment of the present invention, an electric device in which any one of the above-described charging devices is incorporated.

  The charging device, the charging system, and the electric device having such a configuration can efficiently charge the lithium ion secondary battery so that the charging time is shortened.

Embodiments according to the present invention will be described below with reference to the drawings. In addition, the structure which attached | subjected the same code | symbol in each figure shows that it is the same structure, The description is abbreviate | omitted.
(Configuration of the first embodiment)
Drawing 1 is a figure showing the composition of the charge system in an embodiment. In FIG. 1, the charging system 1 includes a charging device 2 and a secondary battery device 3, and measures a charging current Ic and a battery voltage Vb to measure the lithium ion secondary battery 31 of the secondary battery device 3. In this type, the charging / discharging state is monitored on the charging device 2 side. The charging device 1 measures the current I and the voltage E as the charging current Ic and the battery voltage Vb from the electric line through which the charging current Ic to the lithium ion secondary battery 31 of the secondary battery device 3 flows. 3 is a device that charges the lithium ion secondary battery 31 by a constant current-constant voltage charging method, and includes charging terminals Ts1, Ts2, a voltage measuring unit 11, a power supply control unit 12, a DC power supply unit 13, and a current. And a measurement unit 14. The secondary battery device 3 is connected between the battery terminals Tb1 and Tb2 for connection to the charging terminals Ts1 and Ts2 of the charging device 2 and between the battery terminals Tb1 and Tb2, and one or a plurality of lithium ion secondary battery cells 41 ( 41-1, 41-2,..., 41-n) and a lithium ion secondary battery 31. The plurality of lithium ion secondary battery cells 41 may all be connected in series, or a predetermined number may be connected in series to form a cell group, and each cell group may be connected in parallel. The connection is appropriately made according to the rating of the battery device 3 and the rating of one lithium ion secondary battery cell 41.

  The charging terminals Ts1 and Ts2 are electrode terminals for outputting electric power for charging the secondary battery device 3 to be charged and for connecting to the battery terminals Tb1 and Tb2 of the secondary battery device 3.

  The voltage measuring unit 11 is a circuit that is connected to the charging terminals Ts1 and Ts2, measures a voltage E between the charging terminals Ts1 and Ts2, and outputs the measured voltage (measured voltage) E to the power supply control unit 12. For example, the voltage measuring unit 11 is connected between the charging terminals Ts1 and Ts2 and connected between the two resistors connected in series and the charging terminals Ts1 and Ts2 output from the interconnection point of these two resistors. An analog / digital conversion unit (hereinafter abbreviated as “A / D conversion unit”) that converts a divided voltage with respect to the voltage from an analog signal to a digital signal and outputs the converted voltage to the power supply control unit 12 as a measurement voltage. Is done.

  The DC power supply unit 13 is connected to the charging terminals Ts1 and Ts2, and supplies power for charging the secondary battery device 3 to the secondary battery device 3 through the charging terminals Ts1 and Ts2 while adjusting the power value. This is a DC power supply circuit. For example, in this embodiment, the DC power supply unit 13 is connected to the power supply unit 26 that generates power for charging the secondary battery device 3 and the output of the power supply unit 26 (charges the lithium ion secondary battery 31). And a charging current adjusting unit 27 that adjusts the output current value Ix under the control of the power supply control unit 12. The power supply unit 26 includes, for example, a rectifier circuit that rectifies a commercial power source into direct current, a smoothing circuit that smoothes the direct current rectified by the rectifier circuit, and a DC / DC that converts the direct current voltage value of the smoothing circuit into a desired voltage value. And a converter. The charging current adjustment unit 27 is a circuit that adjusts the current value I of the output of the power supply unit 26 by adjusting the current energization time under the control of the power supply control unit 12, for example. And a switching element (for example, a transistor such as a field effect transistor) that turns on and off the current flow according to a control signal input to the control terminal.

  The current measuring unit 14 is inserted in a wire path through which a charging current Ic for charging the lithium ion secondary battery 31 flows, and a current that flows from the DC power supply unit 13 to the secondary battery device 3 via the charging terminals Ts1 and Ts2. I is measured, and the measured current (measured current) I is output to the power supply controller 12. More specifically, the DC power supply unit 13 is disposed between the DC power supply unit 13 and the charging terminal Ts2 in the present embodiment. The current measurement unit 14 includes, for example, a resistor and an A / D conversion circuit that A / D converts the voltage between the terminals generated by the current flowing through the resistor and outputs the voltage as a measurement current to the power supply control unit 12. Is done.

  The power supply controller 12 performs constant current charging of the lithium ion secondary battery 31 to be charged in the secondary battery device 3 until the battery voltage Vb of the lithium ion secondary battery 31 reaches the set voltage value Eth, After the battery voltage Vb of the ion secondary battery 31 reaches the set voltage value Eth, the battery voltage Vb of the lithium ion secondary battery 31 is set to the set voltage until the charging current Ic of the lithium ion secondary battery 31 reaches the set current value Ith. The measured voltage measured by the voltage measuring unit 11 and the measured current measured by the current measuring unit 14 so as to be charged by a constant current-constant voltage charging method in which constant voltage charging is performed with a charging current Ic that does not substantially exceed the value Eth. The charging current adjusting unit 27 of the DC power supply unit 13 is controlled based on the above. The power supply control unit 12 functionally charges a current having a current value smaller than the current value of the charging current during charging from the DC power supply unit 13 during charging at least one of constant current charging and constant voltage charging. Lithium ions via the charging terminals Ts1, Ts2 and the battery terminals Tb1, Tb2 in the voltage measuring unit 11 by flowing to the lithium ion secondary battery 31 of the secondary battery device 3 via the terminals Ts1, Ts2 and the battery terminals Tb1, Tb2. The charging control unit 21 that measures the voltage of the secondary battery 31 and controls the charging current adjustment unit 27 of the DC power supply unit 13 so as to perform the charging based on the measurement result, and the charging control unit 21 sets the predetermined time tn. When set, the timer unit 22 that starts measuring time and notifies the charging control unit 21 when the predetermined time tn has passed, and charging in the case of charging with a constant current. Current value Icc of current Ic, set voltage value Eth which is voltage value E of charging voltage Ec when charging at a constant voltage (applied to lithium ion secondary battery 31 that does not cause deterioration of lithium ion secondary battery 31 due to overcharging) The upper limit voltage value of the possible charging voltage Ec, the voltage value of the charging voltage Ec for determining the end of constant current charging), and the set current value Ith that is the current value I of the charging current Ic for determining the end of charging. And the like, and a control data storage unit 23 for previously storing the information. These current value Icc, set voltage value Eth, and set current value Ith are appropriately set according to the rating of the lithium ion secondary battery 31 and the rating of the lithium ion secondary battery cell 41. The power supply control unit 12 stores, for example, a control program such as a central processing unit (CPU) that performs arithmetic processing, a charging program for realizing a constant current-constant voltage charging method, which will be described later, data, and the like Non-volatile memory elements such as ROM (Read Only Memory) and EEPROM (Electrically Erasable Programmable Read Only Memory), for example, RAM (Random Access Memory) serving as a so-called CPU working memory for temporarily storing data, etc. A volatile memory element and a microcomputer including a peripheral circuit.

Next, the operation of this embodiment will be described.
(Operation of the first embodiment)
2 and 3 are flowcharts showing the constant current-constant voltage charging operation of the charging device according to the first embodiment. FIG. 4 is a diagram illustrating temporal changes in current and voltage in constant current-constant voltage charging. FIG. 4A is a graph of the temporal change in current, the horizontal axis is the time shown in min (minutes), and the vertical axis is the current shown in A units. FIG. 4B is a graph of the temporal change in voltage, the horizontal axis is the time indicated in min (minutes), and the vertical axis is the voltage indicated in V units. A solid line represents a temporal change in current and voltage in the present embodiment, and a broken line represents a charge of the type in which the charge / discharge state monitoring for the lithium ion secondary battery described in the background art section is performed on the charging device side. It represents the time variation of current and voltage in the system.

  2 to 4, when the secondary battery device 3 is set in the charging device 2 and charging is started, the charging control unit 21 in the power control unit 12 of the charging device 2 initializes the timer unit 22. After that, a predetermined time tn is set in the timer unit 22, and the timer unit 22 is started to measure time (S11). The timer unit 22 starts measuring time when the predetermined time tn is set by the charge control unit 21, and notifies the charge control unit 21 when the predetermined time tn has elapsed.

  Next, the charging control unit 21 adjusts the energizing time of the charging current adjusting unit 27 while referring to the measured current I of the current measuring unit 14 to set a current value Icc that is set in advance when performing constant current charging. The charging current adjusting unit 27 of the DC power supply unit 13 is controlled so that the current I flows from the charging device 2 to the secondary battery device 3 through the charging terminals Ts1, Ts2 and the battery terminals Tb1, Tb2 (S12). Thereby, the charging device 2 charges the lithium ion secondary battery 31 of the secondary battery device 3 with a constant current having a current value Icc.

  Next, the charging control unit 21 determines whether or not the predetermined time tn has passed (S13). More specifically, in the present embodiment, the charging control unit 21 determines that the predetermined time tn has elapsed when the timer unit 22 notifies that the predetermined time tn has elapsed, If the timer unit 22 has not notified that the predetermined time tn has elapsed, it is determined that the predetermined time tn has not elapsed.

  As a result of the determination in step S13, when the predetermined time tn has not elapsed (No), the charging control unit 21 acquires the voltage value Ex of the measurement voltage E from the voltage measurement unit 11, and this is obtained as the battery voltage Vb. (S14). Then, the charge control unit 21 determines whether or not the voltage value Ex of the measurement voltage E that is the battery voltage Vb is equal to or greater than a predetermined set voltage value Eth (S18). Thus, the end of constant current charging is determined.

  If the result of determination in step S18 is that the voltage value Ex of the measured voltage E is equal to or greater than a predetermined set voltage value Eth (Ex ≧ Eth), the constant current charging is terminated, and the charge control unit 21 performs processing described later. On the other hand, when the voltage value Ex of the measurement voltage E is less than the predetermined set voltage value Eth (Ex <Eth), the constant current charging is continued, and the charging control unit 21 performs the process S12. Return to.

  Because of this operation, the charging control unit 21 charges the predetermined constant current value Icc until the voltage value Ex of the measurement voltage E is less than the predetermined set voltage value Eth and the predetermined time tn has elapsed. The process S12, the process S13, the process S14 and the process S18 are repeated with the measured voltage E measured by the voltage measuring unit 11 in a state where the charging current adjusting unit 15 is controlled so as to flow from the device 2 to the secondary battery device 3 as the battery voltage Vb. , Perform constant current charging. As a result, as shown in FIG. 4, the lithium ion secondary battery 31 is charged with the charging current Ic having a constant current value Icc, and the measured voltage of the voltage measuring unit 11 gradually increases with time.

  On the other hand, if the result of determination in step S13 is that the predetermined time tn has elapsed (Yes), the charging control unit 21 refers to the measured current I of the current measuring unit 14 while energizing the charging current adjusting unit 27. Is adjusted so that a current I having a current value Is smaller than the current value Icc of the charging current Ic during constant current charging is supplied from the charging device 2 via the charging terminals Ts1, Ts2 and the battery terminals Tb1, Tb2. 3 is controlled so as to flow to 3 (S15).

  Next, the charge control unit 21 acquires the voltage value Ex of the measurement voltage E from the voltage measurement unit 11, and sets this as the battery voltage Vb (S16).

The voltage value Ex of the measurement voltage E is obtained by passing a current I having a current value Is smaller than the current value Icc of the charging current Ic during constant current charging from the charging device 2 to the secondary battery device 3, Since E is measured, the voltage measuring unit 11 keeps the current value Icc of the charging current Ic during constant current charging flowing from the charging device 2 to the secondary battery device 3 as in the process S14. as compared with the case of measuring the voltage E, becomes a value closer to the actual battery voltage Vb in a lithium ion secondary battery 31, the error V _R0 decreases to the actual battery voltage Vb.

For this reason, as the current value Is in the process S15 is closer to 0, for example, the contact resistance between the charging terminals Ts1 and Ts2 and the battery terminals Tb1 and Tb2, or the circuit pattern from the DC power supply unit 13 to the lithium ion secondary battery 31. since the voltage drop is reduced based on the resistance due, the voltage value Ex measured voltage E becomes a value closer to the actual battery voltage Vb, since the error V _R0 to the actual battery voltage Vb becomes smaller, the current in the processing S15 The value Is is preferably a value closer to 0.

  Next, similarly to the process S11, the charging control unit 21 initializes the timer unit 22, sets a predetermined time tn in the timer unit 22, and causes the timer unit 22 to start measuring time (S17).

  Then, the charge control unit 21 executes the process S18, and determines whether or not the voltage value Ex of the measured voltage E that is the battery voltage Vb in the process S16 is equal to or greater than a predetermined set voltage value Eth. Since the voltage value Ex of the measured voltage E in this determination is closer to the actual battery voltage Vb than the voltage value Ex acquired in the process S14, the end of the constant current charging is determined using the voltage value Ex acquired in the process S14. It is possible to judge more accurately than in the case of doing so.

  As described above, when the voltage value Ex of the measurement voltage E is less than the predetermined set voltage value Eth and the predetermined time tn elapses, processing S15 to processing S18 are executed, and the current value Icc of the charging current Ic during constant current charging is determined. A current I having a smaller current value Is is caused to flow from the charging device 2 to the secondary battery device 3, and in this state, the voltage E is measured by the voltage measuring unit 11 to determine the end of constant current charging. As a result, as shown in FIG. 4, when a predetermined time tn (tn = t1 in the example shown in FIG. 4) elapses, the charging current Ic becomes a current value Is smaller than the current value Icc, for example, charging terminals Ts1, Ts2 The voltage measuring unit 11 measures the voltage E with reduced influence of voltage drop based on the contact resistance between the battery terminals Tb1 and Tb2 and the resistance of the circuit pattern from the DC power supply unit 13 to the lithium ion secondary battery 31. .

  Then, the process S12, the process S13, the process S14, and the process S18 are repeated again, and when the predetermined time t1 has elapsed, the processes S15 to S18 are executed. Such a process is repeated until the voltage value Ex of the measurement voltage E becomes equal to or higher than a predetermined set voltage value Eth. As a result, as shown in FIG. 4, the lithium ion secondary battery 31 is charged with the charging current Ic at a constant current value Icc, and the measured voltage E of the voltage measuring unit 11 gradually increases as time elapses. Whenever the time tn (tn = t1 in the example shown in FIG. 4) elapses, the charging current Ic becomes a current value Is smaller than the current value Icc, and the voltage E in which the influence of the voltage drop is reduced is measured. Measured at section 11.

  In this way, every time the predetermined time tn elapses, the charging current Ic is set to the current value Is smaller than the current value Icc, and the voltage E in which the influence of the voltage drop is reduced is measured by the voltage measuring unit 11, and constant current charging is performed. Therefore, in the present invention, the current value Icc of constant current charging can be increased as compared with the case where the present invention is not applied, so that the current I and the voltage E are as shown by the solid line in FIG. Thus, the lithium ion secondary battery 31 can be efficiently charged with a constant current so that the charging time is shortened.

  On the other hand, in process S19, the charging control unit 21 adjusts the energizing time of the charging current adjusting unit 27 while referring to the measured current I of the current measuring unit 14 in the same manner as in process S15, thereby charging during constant current charging. The charging current adjusting unit 27 of the DC power supply unit 13 is controlled so that the current I having a current value Is smaller than the current value Icc of the current Ic flows from the charging device 2 to the secondary battery device 3.

  Next, the charge control unit 21 acquires the voltage value Ex of the measurement voltage E from the voltage measurement unit 11 as in the process S16, and sets this as the battery voltage Vb (S20).

  Next, similarly to the process S18, the charge control unit 21 determines whether or not the voltage value Ex of the measured voltage E that is the battery voltage Vb in the process S19 is equal to or greater than a predetermined set voltage value Eth (S21).

  If the result of determination in step S21 is that the voltage value Ex of the measured voltage E is equal to or greater than a predetermined set voltage value Eth (Ex ≧ Eth), the constant current charging is terminated, and the charge control unit 21 On the other hand, when the voltage value Ex of the measurement voltage E is less than the predetermined set voltage value Eth (Ex <Eth), the constant current charging is continued, and the charging control unit 21 performs the process S12. Return to.

As described above, when it is determined that the voltage value Ex of the measurement voltage E is equal to or higher than the predetermined set voltage value Eth (Ex ≧ Eth) in the determination of the process S18, the processes of the processes S19 to S21 are executed. When the determination in step S18 is performed using the voltage value Ex of the measured voltage E that is the battery voltage Vb in step S14, and it is determined that the voltage value Ex of the measured voltage E is equal to or greater than a predetermined set voltage value Eth (Ex ≧ Eth) in, there is a case where the voltage value Ex measured voltage E of the step S14 includes a relatively large error V _R0 with respect to the actual battery voltage Vb, in order to determine more accurately the end of the constant current charging is there.

  When the constant current charging is completed by executing the processes S11 to S21, in the process S22, the charging control unit 21 first supplies the current charging current Ic as the current value Icv of the initial charging current Ic in the constant voltage charging. Store in the control unit 12. Then, the charging control unit 21 adjusts the energization time of the charging current adjusting unit 27 so that the current of the current value Icv stored in the power supply control unit 12 is supplied from the charging device 2 to the charging terminals Ts1, Ts2, and the battery terminal Tb1. The charging current adjusting unit 27 of the DC power supply unit 13 is controlled so as to flow to the secondary battery device 3 through Tb2 (S23). As a result, the charging device 2 charges the secondary battery device 3 with the current value Icv.

  Next, the charge control unit 21 acquires the voltage value Ex of the measurement voltage E from the voltage measurement unit 11, and sets this as the battery voltage Vb (S24).

  Next, the charge control unit 21 determines whether or not the voltage value Ex of the measurement voltage E is equal to or greater than a predetermined set voltage value Eth (S25).

  When the voltage value Ex of the measurement voltage E is less than the predetermined set voltage value Eth as a result of the determination in the process S25 (Ex <Eth), the charge control unit 21 has a margin ΔE (= Eth-Ex), the current value Icv of the charging current Ic stored in the power supply control unit 12 is increased by a predetermined value ΔIcv (Icv = Icv + ΔIcv), and the increased current value Icv is a constant voltage. The current value Icv of the charging current Ic in charging is stored in the power supply control unit 12, and the process returns to the process S23 (S26). As a result, the charging current Ic having the current value Icv increased by the predetermined value ΔIcv in step S23 flows from the charging device 2 to the secondary battery device 3, and the secondary battery device 3 is charged.

  This process S26 may be omitted. That is, as a result of the determination in the process S25, when the voltage value Ex of the measured voltage E is less than the predetermined set voltage value Eth (Ex <Eth), the charge control unit 21 performs the process without executing the process S26. It returns to processing S23. With this configuration, the charging control unit 21 does not increase the charging current Ic in the case of constant voltage charging, so that overcharging can be avoided, and safety and reliability are improved.

  On the other hand, when the voltage value Ex of the measurement voltage E is equal to or greater than the predetermined set voltage value Eth (Ex ≧ Eth) as a result of the determination in the process S25, the charge control unit 21 sets the measurement current I of the current measurement unit 14 to the measured current I. The current I having a current value Is smaller than the current value Icv of the charging current Ic during constant voltage charging flows from the charging device 2 to the secondary battery device 3 by adjusting the energization time of the charging current adjusting unit 27 while referring to it. In this manner, the charging current adjusting unit 27 of the DC power supply unit 13 is controlled (S27).

  Next, the charge control unit 21 acquires the voltage value Ex of the measurement voltage E from the voltage measurement unit 11, and sets this as the battery voltage Vb (S28).

  Next, the charge control unit 21 determines that the voltage value Ex of the measurement voltage E is equal to or greater than a predetermined set voltage value Eth and the current value Icv of the charge current Ic during constant voltage charging is equal to or less than the predetermined set current value Ith. It is determined whether or not there is (S29). This determines the end of constant voltage charging.

The voltage value Ex of the measured voltage E is supplied from the charging device 2 to the secondary battery device 3 by passing a current I having a current value Is smaller than the current value Icv of the charging current Ic during constant voltage charging. Is measured by the voltage measuring unit 11 while the current I having the current value Icv of the charging current Ic during constant voltage charging is flowing from the charging device 2 to the secondary battery device 3 as in step S24. as compared with the case of measuring the voltage E, becomes a value closer to the actual battery voltage Vb in a lithium ion secondary battery 31, the error V _R0 decreases to the actual battery voltage Vb. Therefore, the determination can be made more accurately than when the voltage measurement unit 11 measures the voltage E with the current value Icv of the charging current Ic and determines the end of constant voltage charging. Therefore, the charging device 3 can efficiently charge the lithium ion secondary battery 31 so as to shorten the charging time without deteriorating the lithium ion secondary battery 31.

  As a result of the determination in step S29, when the voltage value Ex of the measured voltage E is equal to or greater than a predetermined set voltage value Eth and the current value Icv of the charging current Ic during constant voltage charging is equal to or smaller than the predetermined set current value Ith ( (Ex ≧ Eth and Icv ≦ Ith) is the end of constant voltage charging, that is, the end of charging, and the charging control unit 21 ends the main process of charging the lithium ion secondary battery 31.

  On the other hand, as a result of the determination in step S29, if the current value Icv of the charging current Ic during constant voltage charging is larger than the predetermined set current value Ith (Icv> Ith), the constant voltage charging is continued, and the charging control unit 21. First, the charging control unit 21 determines whether or not the voltage value Ex of the measurement voltage E is equal to or greater than a predetermined set voltage value Eth (S30).

  As a result of the determination in step S30, when the voltage value Ex of the measurement voltage E is equal to or greater than a predetermined set voltage value Eth (Ex ≧ Eth), the charge control unit 21 reduces the voltage value Ex of the charge voltage Ec. The current value Icv of the charging current Ic stored in the power supply control unit 12 is decreased by a predetermined value ΔIcv (Icv = Icv−ΔIcv), and the decreased current value Icv is the current value of the charging current in constant voltage charging. Icv is stored in the power supply controller 12 and the process returns to the process S23 (S31). As a result, the charging current Ic having the current value Icv decreased by the predetermined value ΔIcv in step S23 flows from the charging device 2 to the secondary battery device 3, and the secondary battery device 3 is charged. The predetermined value ΔIcv is appropriately set according to the specifications of the charging device 2, and the predetermined value ΔIcv when the charging current Ic is increased in step S26 and the charging current Ic is decreased in step S31. The predetermined value ΔIcv in the case may be the same or different.

  On the other hand, when the voltage value Ex of the measured voltage E is less than the predetermined set voltage value Eth (Ex <Eth) as a result of the determination in the process S30, the charge control unit 21 stores the power control unit 12 in the power supply control unit 12. In order to continue the constant current charging with the current value Icv of the charging current Ic, the current value Icv of the current charging current Ic is held, that is, the current value Icv stored in the power supply control unit 12 is maintained. The process returns to process S23 (S32). As a result, in the process S23, the charging current Ic having the current value Icv flows from the charging device 2 to the secondary battery device 3, and the secondary battery device 3 is charged.

  By performing each of the processes S22 to S32, the charging device 2 allows the battery voltage Vb of the lithium ion secondary battery 31 until the charging current Ic of the lithium ion secondary battery 31 reaches the set current value Ith. The constant voltage charging is performed at the current value Icv of the charging current Ic that does not substantially exceed the set voltage value Eth. As a result, as shown in FIG. 4, the lithium ion secondary battery 31 is charged with the charging current Ic being the current value Icv, and the measured voltage E of the voltage measuring unit 11 gradually decreases with time. On the other hand, when the voltage value Ex of the measurement voltage E becomes equal to or higher than the predetermined set voltage value Eth in the process S25, as shown in FIG. 4, the charging current Ic becomes a current value Is smaller than the current value Icc. The voltage measuring unit is a voltage E in which the influence of a voltage drop based on the contact resistance between the charging terminals Ts1, Ts2 and the battery terminals Tb1, Tb2, the resistance due to the circuit pattern from the DC power supply unit 13 to the lithium ion secondary battery 31, and the like is reduced. 11 is measured. In the case where it is determined in step S29 that the constant voltage charging is finished, a current I having a current value Is smaller than the current value Icv of the charging current Ic during constant voltage charging is passed from the charging device 2 to the secondary battery device 3. Since the measurement voltage E measured by the voltage measurement unit 11 is used, this determination is made with a value closer to the actual battery voltage Vb in the lithium ion secondary battery 31, and the determination can be made more accurately. Since the current value Icv for constant voltage charging can be increased as compared with the case where no is applied, the current I and the voltage E change as shown by the solid lines in FIG. For this reason, the charging device 3 can efficiently charge the lithium ion secondary battery 31 so as to shorten the charging time without deteriorating the lithium ion secondary battery 31.

  In the first embodiment described above, the processes S19 to S21 in FIG. 2 may be omitted in order to reduce the information processing load of the power supply control unit 12 and the charging time. That is, as a result of the determination in the process S18, when the voltage value Ex of the measurement voltage E is equal to or greater than a predetermined set voltage value Eth (Ex ≧ Eth), the process S22 is executed, while the voltage value Ex of the measurement voltage E is When the voltage is less than the predetermined set voltage value Eth (E <Eth), the charging device 2 may be configured so that the process returns to the process S12. Compared with the case where the operation shown in FIG. 2 described above is performed by such a configuration, the information processing load of the power supply control unit 12 corresponding to the portion in which the processes S19 to S21 in FIG. 2 are omitted is reduced, and The charge time is reduced accordingly.

  In the first embodiment described above, the predetermined time tn may be changed instead of being constant, and the current value Is at each predetermined time tn may be changed not constant.

Next, another embodiment will be described.
(Configuration of Second Embodiment)
In the first embodiment, a current I having a current value Is smaller than the current value Ix of the charging current Ic during charging is supplied from the charging device 2 to the secondary battery device 3 at a predetermined time tn. By measuring the voltage E, the voltage value Ex of the measurement voltage E that is closer to the actual battery voltage Vb of the actual lithium ion secondary battery 31 is obtained and the charging is performed. For example, the charging terminal Ts1, The resistance value from the DC power supply unit 13 to the lithium ion secondary battery 31 due to the contact resistance between Ts2 and the battery terminals Tb1 and Tb2, the resistance due to the circuit pattern from the DC power supply unit 13 to the lithium ion secondary battery 31, etc. It may be configured to correct the set voltage value Eth based on the estimation. Even if comprised in this way, the lithium ion secondary battery 31 can be charged efficiently, without deteriorating the lithium ion secondary battery 31.

  FIG. 5 is a diagram illustrating a circuit equivalent model of the charging system. In FIG. 5, the circuit equivalent model of the charging system 1 shown in FIG. 1 includes a constant current and constant voltage source S corresponding to the DC power supply unit 13 of the charging device 2, a resistor R and a lithium ion secondary battery of the secondary battery device 3. 31 are connected in series. The resistance R is, for example, from the DC power supply unit 13 to the lithium ion caused by contact resistance between the charging terminals Ts1 and Ts2 and the battery terminals Tb1 and Tb2 or resistance due to a circuit pattern from the DC power supply unit 13 to the lithium ion secondary battery 31. It is a resistance to the secondary battery 31.

In such a circuit equivalent model, the voltage value of the constant voltage constant current source S is E ₀ , the resistance value of the resistor R is R ₀ , and the voltage values of the battery voltages of the lithium ion secondary battery 31 are Vb 1 and Vb 2. When the current value of the charging current Ic flowing from the constant voltage source S to the lithium ion secondary battery 31 through the resistor R is Is1 and Is2, Expression 1-1 and Expression 1-2 are established. In the expression, “·” is a multiplication operator.
Vb1 = E ₀ −R ₀ · Is1 (Formula 1-1)
Vb2 = E ₀ −R ₀ · Is2 (Formula 1-2)
Therefore, Expression 2 is established from Expression 1-1 and Expression 1-2.
R ₀ = (Vb 2 −Vb 1) / (Is 1 −Is 2) (Formula 2)

Therefore, the resistance value R ₀ of the resistor R is estimated by flowing the current values Is 1 and Is 2 of the two charging currents from the DC power supply unit 13 to the lithium ion secondary battery 31 and measuring the voltage E by the voltage measuring unit 11. The voltage drop R ₀ · Ix due to the resistance R can be obtained by multiplying the resistance value R ₀ by the current value of the charging current Ic in the charging method. By correcting the set voltage value Eth with the voltage drop R ₀ · Ix, the set voltage value Eth that eliminates the influence of the voltage drop R ₀ · Ix due to the resistor R can be obtained, so that the lithium ion secondary battery 31 can be efficiently used. Can be charged well.

  Therefore, the charging device 2 and the secondary battery device 3 of the charging system 1 according to the second embodiment are the charging system 1 according to the first embodiment, except that the charging control unit 21 operates as described later. Since the configuration is the same as that of the charging device 2 and the secondary battery device 3, description thereof is omitted.

  The power supply control unit 21 according to the second embodiment includes different first and second powers that are smaller than the current value of the charging current Ic during charging during at least one of constant current charging and constant voltage charging. Voltage measurement is performed by flowing first and second currents of current values Is1 and Is2 from the DC power supply unit 13 to the lithium ion secondary battery 31 of the secondary battery device 3 via the charging terminals Ts1 and Ts2 and the battery terminals Tb1 and Tb2. The unit 11 measures the first and second voltages of the lithium ion secondary battery 31 via the charging terminals Ts1 and Ts2 and the battery terminals Tb1 and Tb2, and the first and second current values Is1 of the first and second currents. , Is2, and the charging current adjusting unit 27 of the DC power supply unit 13 so as to perform the charging by correcting the set voltage value Eth based on the first and second voltage values Vb1 and Vb2 of the measurement result. To your.

Next, the operation of this embodiment will be described.
(Operation of Second Embodiment)
6 and 7 are flowcharts showing the constant current-constant voltage charging operation of the charging device according to the second embodiment. 6 and 7, when the secondary battery device 3 is set in the charging device 2 and charging is started, the charging control unit 21 in the power source control unit 12 of the charging device 2 performs processing S11 and processing shown in FIG. Similarly to S12 and S13, the setting of the timer unit 22 and the timing start process (S41), the constant current charging process (S42), and the determination process (S43) after the predetermined time tn are sequentially executed.

  As a result of the determination in the process S43, when the predetermined time tn has not elapsed (No), the charge control unit 21 executes the acquisition process (S44) of the voltage value Ex as in the process S14, and the process S18. Similarly, the determination process (S49) of voltage value Ex ≧ set voltage value Et is sequentially executed. As a result of the determination in this process S69, when the voltage value Ex of the measured voltage E is equal to or greater than a predetermined set voltage value Eth (Ex ≧ Eth), the constant current charging is completed, and the charging control unit 21 is described later. On the other hand, when the voltage value Ex of the measurement voltage E is less than the predetermined set voltage value Eth (Ex <Eth), the constant current charging is continued, and the charging control unit 21 processes the process. Return to S42.

  On the other hand, if the result of determination in step S43 is that the predetermined time tn has elapsed (Yes), the charge control unit 21 first refers to the measurement current I of the current measurement unit 14 while the charge current adjustment unit 27 By adjusting the energization time, the first current having the first current value Is1 smaller than the current value Icc of the charging current Ic during constant current charging is supplied from the charging device 2 via the charging terminals Ts1, Ts2 and the battery terminals Tb1, Tb2. Then, the charging current adjusting unit 27 of the DC power supply unit 13 is controlled so as to flow to the secondary battery device 3, and the voltage value Ex of the measured voltage E is obtained from the voltage measuring unit 11, and this is used as the first voltage value of the battery voltage Vb. Vb1. Then, the charging control unit 21 adjusts the energizing time of the charging current adjusting unit 27 while referring to the measured current I of the current measuring unit 14, thereby reducing the current value Icc of the charging current Ic during constant current charging. The charging current adjusting unit 27 of the DC power supply unit 13 is controlled such that the second current I having the two current values Is2 flows from the charging device 2 to the secondary battery device 3 via the charging terminals Ts1 and Ts2 and the battery terminals Tb1 and Tb2. The voltage value Ex of the measurement voltage E is obtained from the voltage measurement unit 11, and this is set as the second voltage value Vb2 of the battery voltage Vb. The first current value Is1 and the second current value Is2 are different from each other.

  The voltage value Ex of the measurement voltage E is obtained by causing the current I of Is1 and Is2 smaller than the current value Icc of the charging current Ic during constant current charging to flow from the charging device 2 to the secondary battery device 3 to be the voltage measuring unit 11. The voltage E is measured by the voltage measuring unit 11 while the current I having the current value Icc of the charging current Ic during constant current charging is flowing from the charging device 2 to the secondary battery device 3. As compared with the case of measuring, the value is closer to the actual battery voltage Vb in the lithium ion secondary battery 31.

Next, the charge control unit 21 calculates a voltage correction value ΔV for correcting the set voltage value Eth (S46). More specifically, the charging control unit 21 uses the first and second current values Is1 and Is2 and the first and second voltage values Vb1 and Vb2 of the measurement result in Equation 2 to calculate the resistance value _R0 of the resistor R. The voltage correction value ΔV is calculated by calculating the voltage correction value ΔV = R ₀ · Icc using the constant current charging current value Icc.

  Next, the charging control unit 21 corrects the set voltage value Eth using the voltage correction value ΔV (S47). More specifically, the charging control unit 21 corrects the set voltage value Eth by adding the voltage correction value ΔV to the current set voltage value Eth to obtain a new set voltage value Eth (= Eth + ΔV). To do.

  Next, similarly to the process S11, the charge control unit 21 initializes the timer unit 22, sets a predetermined time tn in the timer unit 22, causes the timer unit 22 to start measuring time (S48), and performs the process. It returns to processing S42.

  As described above, the set voltage value Eth is corrected at every elapse of the predetermined time tn, so that the end of the constant current charging in the process S49 can be determined more accurately. Therefore, the charging device 3 can efficiently charge the lithium ion secondary battery 31 so as to shorten the charging time without deteriorating the lithium ion secondary battery 31.

  When the voltage value Ex of the measured voltage E is equal to or greater than the predetermined set voltage value Eth (Ex ≧ Eth) as a result of the determination in the process S49, the charge control unit 21 performs the processes S19 and S20 shown in FIG. Similarly to the process S21, the process of reducing the charging current Ic to the current value Is (S50), the acquisition process of the voltage value Ex (S51), and the determination process of the voltage value Ex ≧ the set voltage value Et (S52) are sequentially performed. Run each. As a result of the determination in this process S52, when the voltage value Ex of the measured voltage E is equal to or greater than a predetermined set voltage value Eth (Ex ≧ Eth), the constant current charging is finished, and the charging control unit 21 is described later. On the other hand, when the voltage value Ex of the measurement voltage E is less than the predetermined set voltage value Eth (Ex <Eth), the constant current charging is continued, and the charging control unit 21 processes the process. Return to S42.

As described above, when it is determined in step S49 that the voltage value Ex of the measured voltage E is equal to or higher than the predetermined set voltage value Eth (Ex ≧ Eth), the processes S50 to S51 are executed. As in the first embodiment, the determination in step S49 is performed using the voltage value Ex of the measurement voltage E that is the battery voltage Vb in step S44, and the voltage value Ex of the measurement voltage E is equal to or greater than a predetermined set voltage value Eth. in case where it is determined that (Ex ≧ Eth), there is a case where the voltage value Ex measured voltage E of the process S44 includes a relatively large error V _R0 with respect to the actual battery voltage Vb, more precisely constant This is to determine the end of current charging.

  When the constant current charging is completed by executing the processing S41 to S52, in the processing S53, the charging control unit 21 first initializes the timer unit 22 and then sets the predetermined time to the timer unit 22 as in the processing S11. The time tn is set and the timer unit 22 is started to measure time.

  Next, the charging control unit 21 stores the current charging current Ic in the power supply control unit 12 as the current value Icv of the initial charging current Ic in the constant voltage charging, similarly to the process S22 shown in FIG. 3 (S54). Then, the charging control unit 21 adjusts the energizing time of the charging current adjusting unit 27 in the same manner as the process S23 shown in FIG. 3, so that the current I of the current value Icv stored in the power control unit 12 is changed to the charging device. The charging current adjusting unit 27 of the DC power supply unit 13 is controlled so as to flow from 2 to the secondary battery device 3 via the charging terminals Ts1, Ts2 and the battery terminals Tb1, Tb2 (S55). As a result, the charging device 2 charges the secondary battery device 3 with the current value Icv.

  Next, the charging control unit 21 determines whether or not the predetermined time tn has elapsed (S56).

  If the predetermined time tn has passed as a result of the determination in step S56 (Yes), the charging control unit 21 sets the charging current Ic to the first and second values in the same manner as in steps S45 to S48 shown in FIG. Measurement processing (S57) for measuring the first and second voltage values Vb1, Vb2 by reducing the current values Is1, Is2, calculation processing (S58) for obtaining the voltage correction value ΔV, and the set voltage value Eth as the voltage correction value Δ The correction process (S59) for correcting with V and the setting of the timer unit 22 and the timing start process (S60) are sequentially executed, and the process returns to the process S55.

  On the other hand, as a result of the determination in step S56, when the predetermined time tn has not elapsed (No), the charging control unit 21 acquires the voltage value Ex (step S24 and step S25 shown in FIG. 3). S61) is executed, and determination processing (S62) of voltage value Ex ≧ set voltage value Et is sequentially executed.

  When the voltage value Ex of the measurement voltage E is less than the predetermined set voltage value Eth as a result of the determination in the process S62 (Ex <Eth), the charge control unit 21 determines the charge current as in the process S26 of FIG. An increase process (S63) for increasing the current value Icv of Ic by a predetermined value ΔIcv is executed, and the process returns to process S55. As a result, the charging current Ic having the current value Icv increased by the predetermined value ΔIcv in step S55 flows from the charging device 2 to the secondary battery device 3, and the secondary battery device 3 is charged.

  This process S63 may be omitted. That is, as a result of the determination in the process S62, when the voltage value Ex of the measured voltage E is less than the predetermined set voltage value Eth (Ex <Eth), the charge control unit 21 performs the process without executing the process S63. It returns to processing S55. With this configuration, the charging control unit 21 does not increase the charging current Ic in the case of constant voltage charging, so that overcharging can be avoided, and safety and reliability are improved.

  On the other hand, as a result of the determination in step S62, when the voltage value Ex of the measured voltage E is equal to or greater than the predetermined set voltage value Eth (Ex ≧ Eth), the charge control unit 21 performs steps S27 to S29 in FIG. Similarly, the process of reducing the charging current Ic to the current value Is (S64) and the acquisition process of the voltage value Ex (S65) are executed, and the determination of the voltage value Ex ≧ the set voltage value Eth and the current value Icv ≦ the set current value Ith is performed. The processing (S65) is sequentially executed.

  As a result of the determination in step S65, when the voltage value Ex of the measurement voltage E is equal to or greater than a predetermined set voltage value Eth and the current value Icv of the charging current Ic during constant voltage charging is equal to or less than the predetermined set current value Ith ( (Ex ≧ Eth and Icv ≦ Ith) is the end of constant voltage charging, that is, the end of charging, and the charging control unit 21 ends the main process of charging the lithium ion secondary battery 31.

  On the other hand, as a result of the determination in step S65, if the current value Icv of the charging current Ic during constant voltage charging is larger than the predetermined set current value Ith (Icv> Ith), the constant voltage charging is continued, and the charging control unit 21. First, the charging control unit 21 executes a determination process (S67) of the voltage value Ex ≧ the set voltage value Eth, similarly to the process S30 illustrated in FIG.

  When the voltage value Ex of the measured voltage E is equal to or greater than the predetermined set voltage value Eth (Ex ≧ Eth) as a result of the determination in the process S67, the charging control unit 21 determines the charging current as in the process S31 of FIG. A decrease process (S68) for decreasing the current value Icv of Ic by a predetermined value ΔIcv is executed, and the process returns to process S55. As a result, the charging current Ic having the current value Icv decreased by the predetermined value ΔIcv in the process S55 flows from the charging device 2 to the secondary battery device 3, and the secondary battery device 3 is charged.

  On the other hand, when the voltage value Ex of the measured voltage E is less than the predetermined set voltage value Eth as a result of the determination in the process S67 (Ex <Eth), the charge control unit 21 performs the same process as the process S32 shown in FIG. Then, a holding process for holding the current value Icv of the current charging current Ic is executed (S69), and the process returns to the process S23. Thereby, in process S55, the charging current Ic of the current value Icv flows from the charging device 2 to the secondary battery device 3, and the secondary battery device 3 is charged.

  Since the set voltage value Eth is corrected every time the predetermined time tn elapses in this way, the lithium ion secondary battery 31 is charged until the charging current Ic of the lithium ion secondary battery 31 in the processes S62 and S66 reaches the set current value Ith. The battery voltage Vb can be determined more accurately with the charging current Icv that does not substantially exceed the set voltage value Eth. For this reason, since the current value Icv of constant voltage charging can be increased as compared with the case where the present invention is not applied, the charging device 3 can shorten the charging time without deteriorating the lithium ion secondary battery 31. The lithium ion secondary battery 31 can be charged efficiently. Further, since the set voltage value Eth is corrected every time the predetermined time tn elapses in this way, it is possible to more accurately determine the end of the constant voltage charging in the process S66. Therefore, the charging device 3 can efficiently charge the lithium ion secondary battery 31 so as to shorten the charging time without deteriorating the lithium ion secondary battery 31.

  As described above, in the charging system 1 according to the second embodiment, the charging device 2 corrects the set voltage value Eth every elapse of the predetermined time tn, so that the charging time can be reduced without deteriorating the lithium ion secondary battery 31. The lithium ion secondary battery 31 can be charged efficiently so as to be shorter.

  In the second embodiment described above, the processing S50 to S52 in FIG. 6 may be omitted in order to reduce the information processing load of the power supply control unit 12 and shorten the charging time. That is, as a result of the determination in the process S49, when the voltage value Ex of the measurement voltage E is equal to or greater than the predetermined set voltage value Eth (Ex ≧ Eth), the process S53 is executed, while the voltage value Ex of the measurement voltage E is When the voltage is less than the predetermined set voltage value Eth (Ex <Eth), the charging device 2 may be configured such that the process returns to the process S42. By configuring in this way, the information processing load of the power supply control unit 12 corresponding to the amount of omitting the processes S50 to S52 of FIG. 6 is reduced as compared with the case where the operation shown in FIG. 6 is performed, and The charge time is reduced accordingly.

  In the above-described embodiment, the predetermined time tn may be changed without being constant, and the current value Is at each predetermined time tn may be changed without being constant.

  FIG. 8 is a diagram illustrating temperature characteristics of the set voltage value. The horizontal axis in FIG. 8 is the temperature Temp, and the vertical axis is the set voltage value Eth (Temp). The set voltage value Eth of the lithium ion secondary battery 31 (lithium ion secondary battery cell 41) depends on the temperature Temp as shown in FIG. The set voltage value Eth gradually increases as the temperature Temp increases.

  For this reason, in the above-described first and second embodiments, the charging device 2 may be configured to correct the set voltage value Eth according to the temperature. With this configuration, it is possible to reduce a design margin in consideration of a change in the set voltage value Eth accompanying a temperature change.

  The configuration of the charging system 1 that corrects the set voltage value Eth according to temperature is such that the secondary battery device 3 according to the first and second embodiments has a lithium ion secondary as shown by a broken line in FIG. A temperature detection unit 32 for detecting the temperature of the battery 31 as the battery temperature Tb; and a battery side communication terminal Tc1 for outputting a detection result detected by the temperature detection unit 32 and connecting to the charging side communication terminal Tc2. As shown by a broken line in FIG. 1, the charging device 2 according to the first and second embodiments is connected to the battery side communication terminal Tc1 that outputs the detection result detected by the temperature detection unit 32 of the secondary battery device 3. A charging side communication terminal Tc2 and an A / D conversion unit 16 that A / D converts the detection result input from the charging side temperature terminal Tc2 and outputs the result to the power supply control unit 12 as the battery temperature Tb are further provided. The temperature detection unit 32 is a temperature detection element whose resistance value changes depending on the temperature of a thermistor, for example. One temperature detection element may be provided for the lithium ion secondary battery 31, and a plurality of lithium detection elements may be provided. One temperature detection element may be provided for the ion secondary battery cell 41, and one temperature detection element may be provided for each lithium ion secondary battery cell 41. In the case where a plurality of temperature detection elements are provided, the temperature characteristic of the set voltage value Eth increases as the temperature rises as shown in FIG. Output.

  2 and 3, the charging control unit 21 performs processing S18, processing S21, processing S25, processing S29 and processing S30, and in FIGS. 6 and 7, processing S49, processing S52, processing S54 and processing. Before performing the process of comparing the voltage value Ex of the measured voltage E measured by the voltage measuring unit 11 and the set voltage value Eth as in S60 and S61, the temperature detection unit 32 of the secondary battery device 3 is connected to the battery side. The battery temperature Tb is acquired through the communication terminal Tc1, the charging-side communication terminal Tc2, and the A / D conversion unit 16, and the set voltage value Eth is corrected based on the acquired battery temperature Tb.

  For this correction, for example, a lookup table in which the set voltage value Eth is associated with each of a plurality of temperature ranges is stored in the power supply control unit 12 in advance, and the set voltage corresponding to the battery temperature Tb acquired from the temperature detection unit 32 is stored. This is done by obtaining the value Eth from this lookup table. This lookup table is created, for example, by dividing the temperature characteristic of the set voltage value Eth shown in FIG. 8 into a plurality of temperature ranges and setting the set voltage value Eth in each temperature range.

  Further, for example, in this correction, a function expression indicating the temperature characteristic of the set voltage value Eth is stored in the power supply control unit 12 in advance, and the set voltage value Eth corresponding to the battery temperature Tb obtained from the temperature detection unit 32 is stored in this function. This is done by calculating using an expression. This function formula is created, for example, by approximating the temperature characteristic of the set voltage value Eth by a polynomial.

  With this configuration, it is possible to reduce a design margin in consideration of a change in the set voltage value Eth accompanying a temperature change. And since the setting voltage value Eth is changed according to a temperature change, overcharge can be avoided and safety | security and reliability improve.

  Such a charging device 2 can be applied to various secondary batteries widely used as a driving power source in a battery-powered device. As an example, in the case of a lithium ion secondary battery used as a driving power source for an electric tool. Is described below.

  FIG. 9 is an external configuration diagram illustrating a main part of a rechargeable power tool set to which the charging device according to the embodiment is applied. FIG. 10 is a diagram illustrating a state in which the battery pack is mounted on the mounting portion of the electric tool main body. FIG. 11 is a diagram illustrating a state where the battery pack is mounted in the mounting hole of the charging device.

  In FIG. 9, the rechargeable power tool set 100 includes a power tool main body 110 constituting a rechargeable drill driver, a battery pack (secondary battery device) 120 attached to the power tool main body 110, and the battery pack 120. And a charging device 130 for charging.

  The power tool main body 110 is formed inside the gripping portion of the casing 111 and is provided inside the casing 111 with a mounting portion 112 to which the battery pack 120 is detachably mounted, and current is supplied from the battery pack 120. Motor 113 that is driven by this, and a trigger switch 114 that is provided on the gripping portion of the casing 111 and that controls on / off of the supply of current to the motor 113, and provided at the tip of the casing 111, with drill teeth, etc. And a rotating part 115 to be attached. A pair of electrode terminals 116 connected to the motor 113 are attached to the bottom of the mounting portion 112.

  A battery pack (secondary battery device) 120 includes a main body 123 in which a lithium ion secondary battery 122 and the like configured by including one or a plurality of lithium ion secondary battery cells are housed in a housing 121, and a main body 123, and an electrode portion 124 that is attached to the attachment portion 112 of the electric power tool main body 110. The electrode part 124 is provided with a pair of battery terminals 125 connected to the electrode of the lithium ion secondary battery 122 on the opposite surface of the tip part. When the pair of battery terminals 125 are mounted on the mounting portion 112 of the electric power tool main body 110, the pair of electrode terminals 116 of the mounting portion 112 are pressed against each other. FIG. 10 shows a state in which the battery pack 120 is mounted on the mounting portion 112 of the electric power tool main body 110.

  The charging device 130 includes a circuit block 131 that constitutes a DC power supply unit, a power supply control unit, and the like inside, and a mounting hole portion 132 in which the electrode unit 124 of the battery pack 120 is detachably mounted on the upper surface side. Yes. A pair of charging terminals 133 (only one of them is shown) is provided at an opposing position inside the mounting hole 132, and when the electrode part 124 of the battery pack 120 is mounted, the mounting hole 132 is connected to the pair of battery terminals 125. A pair of charging terminals 133 are pressed against each other. FIG. 11 shows a state in which the battery pack 120 is mounted in the mounting hole 132 of the charging device 130.

  When the battery temperature Tb is detected, as shown by a broken line, a battery that outputs a detection result detected by a temperature detection unit 127 (not shown) that detects the temperature of the lithium ion secondary battery 122 as the battery temperature Tb. The side communication terminal 126 may be provided at the distal end portion of the electrode portion 124, and accordingly, the charging side communication terminal 134 (not shown) may be provided inside the mounting hole portion 132, and the electrode of the battery pack 120 may be provided. When the portion 124 is mounted, the battery-side communication terminal 126 may be configured to be in pressure contact with the charging-side communication terminal 134 of the mounting hole 132.

  Here, the charging device 130 corresponds to the charging device 2 shown in FIG. 1, and the circuit block 131 corresponds to the voltage measurement unit 11, the power supply control unit 12, the DC power supply unit 13, and the current measurement unit 14 shown in FIG. The terminal 133 corresponds to the charging terminals Ts1 and Ts2 shown in FIG. The battery pack 120 corresponds to the secondary battery device 3 shown in FIG. 1, the lithium ion secondary battery 122 corresponds to the lithium ion secondary battery 31 shown in FIG. 1, and the battery terminal 125 corresponds to the battery terminal shown in FIG. This corresponds to Tb1 and Tb2. When the battery temperature Tb is detected and the battery side communication terminal 126 and the charge side communication terminal 134 are provided, the charge side communication terminal 134 corresponds to the charge side communication terminal Tc2 shown in FIG. The terminal 126 corresponds to the battery side communication terminal Tc1 shown in FIG.

  As described above, when the battery pack 120 is mounted on the charging device 130 and the both are connected in a circuit, the charging device 130 charges the battery pack 120 with constant current-constant voltage as described above. For this reason, the lithium ion secondary battery 31 can be efficiently charged so as to shorten the charging time without deteriorating the lithium ion secondary battery 122 of the battery pack 120.

  In addition, the charging device 2 according to the embodiment may be configured to be incorporated in various electric devices such as an electric tool, an electric razor, a mobile phone, and a notebook personal computer. Even in such a configuration, the charging device 2 charges the battery pack 120 at a constant current-constant voltage as described above, so that the charging time can be reduced without deteriorating the lithium ion secondary battery 122 of the battery pack 120. Thus, the lithium ion secondary battery 31 can be charged efficiently so as to shorten the time.

It is a figure which shows the structure of the charging device in embodiment. It is a flowchart (the 1) which shows the operation | movement of the constant current-constant voltage charge of the charging device in 1st Embodiment. It is a flowchart (the 2) which shows the operation | movement of the constant current-constant voltage charge of the charging device in 1st Embodiment. It is a figure which shows the time change of the electric current and voltage in constant current-constant voltage charge. It is a figure which shows the circuit equivalent model of a charging system. It is a flowchart (the 1) which shows the operation | movement of the constant current-constant voltage charge of the charging device in 2nd Embodiment. It is a flowchart (the 2) which shows the operation | movement of the constant current-constant voltage charge of the charging device in 2nd Embodiment. It is a figure which shows the temperature characteristic of a setting voltage value. It is an external appearance block diagram which shows the principal part of the rechargeable electric tool set to which the charging device which concerns on embodiment is applied. It is a figure which shows the state by which the battery pack was mounted | worn with the mounting part of the electric tool main body. It is a figure which shows the state by which the battery pack was mounted | worn in the mounting hole part of the charging device. It is a figure which shows the charge characteristic of a lithium ion secondary battery. It is a block diagram which shows the structure of the charging system which concerns on background art. It is a figure which shows the charge characteristic of a lithium ion secondary battery in the case of performing the charge / discharge state monitoring with respect to a lithium ion secondary battery on the charging device side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Charging system 2 Charging apparatus 3 Secondary battery apparatus 11 Voltage measurement part 12 Power supply control part 13 DC power supply part 14 Current measurement part 16 Analog / digital conversion part 21 Charge control part 22 Timer part 23 Control data storage part 31 Lithium ion secondary Battery 32 Temperature detector 41 Lithium ion secondary battery cell

Claims (6)

The lithium ion secondary battery to be charged is charged at a constant current until the battery voltage of the lithium ion secondary battery reaches a set voltage value, and the battery voltage of the lithium ion secondary battery reaches the set voltage value. In a charging device that performs constant voltage charging with a charging current that does not substantially exceed the set voltage value until the charging current of the lithium ion secondary battery reaches a set current value ,
A power supply for supplying power for charging the lithium ion secondary battery;
A voltage measuring unit for measuring a voltage of the lithium ion secondary battery;
A current measuring unit for measuring a current flowing to the lithium ion secondary battery;
By flowing a current having a current value smaller than the current value of the charging current during the charging from the power supply unit to the lithium ion secondary battery during at least one of the constant current charging and the constant voltage charging. A charging device comprising: a control unit that measures the voltage of the lithium ion secondary battery by the voltage measurement unit and controls the power supply unit to perform the charging based on the measurement result. The power supply control unit supplies a current having a current value smaller than a current value of a charging current during the charging from the power supply unit to the lithium ion secondary battery during at least one of the constant current charging and the constant voltage charging. The voltage measurement unit measures the voltage of the lithium ion secondary battery by flowing the secondary battery, and the power source unit is controlled to perform the charging using the measurement result as the battery voltage. The charging device according to 1. The power supply control unit includes first and second current values that are different from each other during charging and are different from each other during charging at least one of the constant current charging and the constant voltage charging. A first current and a second voltage of the lithium ion secondary battery are measured by the voltage measuring unit by flowing a second current from the power source to the lithium ion secondary battery, and the first of the first and second currents is measured. The power supply unit is controlled to perform the charging by correcting the set voltage value based on the first current value and the second voltage value of the measurement result and the first and second voltage values of the measurement result. Charging device. The charging device according to any one of claims 1 to 3, further comprising a set voltage correction unit that corrects the set voltage value according to a battery temperature of the lithium ion secondary battery. In a charging system comprising a secondary battery device comprising a lithium ion secondary battery and a charging device for charging the lithium ion secondary battery,
The charging system according to claim 1, wherein the charging apparatus is the charging apparatus according to claim 1.   An electric device in which the charging device according to any one of claims 1 to 4 is incorporated.

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