JP4855871B2 - Charger - Google Patents

Description

  The present invention relates to a charging device that charges a battery to be charged (for example, a rechargeable battery such as a secondary battery).

  As this type of charging device, a charging device disclosed in JP-A-6-38392 is known. This charging device receives an alternating current from a commercial power source and supplies a constant current or a constant voltage to a charging target battery (charged battery), a charging control unit that controls the operation of the power source unit, and a voltage of the charging target battery. Voltage detection unit to detect, current detection unit that detects the charging current and inputs the current value to the charge control unit when the current value becomes almost zero, and constant current charging time and protection according to the remaining capacity of the battery to be charged A timer circuit for counting the timer time is provided. In this case, the charging device uses a lithium ion secondary battery as a battery to be charged, and the lithium ion secondary battery has a relationship in which the remaining capacity is substantially proportional to the battery voltage. Therefore, the voltage detection unit that detects the voltage of the battery to be charged functions as a remaining capacity detection unit of the battery to be charged.

  In this charging device, before the start of charging, the charging control unit detects the remaining capacity of the charging target battery based on the voltage of the charging target battery detected via the voltage detection unit, and determines the fixed capacity according to the detected remaining capacity. The current charging time and the protection timer time are determined and set in the timer circuit. Thereafter, constant current charging of the battery to be charged by the power supply unit is started, and the timer circuit starts counting the constant current charging time and the protection timer time. The charge control unit detects whether or not the detected voltage has reached a predetermined voltage by the end of counting the constant current charging time while detecting the voltage of the charging target battery via the voltage detection unit. As a result of this detection, if not reached, the charging control unit determines that an abnormality has occurred in the battery to be charged or the charging device, and stops constant current charging of the power supply unit. On the other hand, when it has reached, the charge control unit causes the power supply unit to start constant voltage charging.

During constant voltage charging, the charge control unit detects the charging current of the battery to be charged via the current detection unit, and whether the detected charging current has dropped to almost zero by the end of the protection timer time count. Detect whether or not. As a result of this detection, when the voltage drops to almost zero, the charging control unit determines that the charging target battery is fully charged, and terminates charging of the charging target battery by the power supply unit. On the other hand, when it does not drop to almost zero, the charging control unit forcibly ends the charging of the charging target battery by the power supply unit. This makes it possible to transfer the battery to be charged to a state close to full charge although it is not yet fully charged, and when constant voltage charging is continued to bring the battery to be charged closer to full charge. In addition, it is possible to avoid an adverse effect (decrease in the life of the battery to be charged) caused by the state of charge being continued for a long time.
JP-A-6-38392 (page 2-3, FIG. 1)

  By the way, there is also a demand for the charging device to charge the charging target battery having a different battery capacity to the fully charged state in a set charging time to complete the charging operation. However, in the conventional charging device, the constant current charging time and the protection timer time set in the timer circuit are determined according to the remaining capacity of the battery to be charged, and the battery capacity of the battery to be charged is not taken into consideration. Therefore, this charging device has a problem to be solved that a charging target battery having different battery capacities cannot be fully charged in a set time to complete a charging operation.

  The present invention has been made to solve such a problem. Regardless of the battery capacity of the battery to be charged, the battery to be charged is fully charged in the set charging time to complete the charging operation. The main object is to provide a charging device.

In order to achieve the above object, a charging device according to claim 1, wherein a power supply unit configured to be able to control a charging current value at the time of charging the charging target battery, and the charging target battery by controlling the power supply unit. Bei example a power control unit for executing the constant current charging Te, the power supply control unit, the running capacitance detection process prior to the start of constant current charging, detecting the remaining capacity and the battery capacity of the charging target cell And a charging device that defines a charging current value at the time of constant current charging based on the detected remaining capacity and battery capacity and a preset target charging time , wherein the power supply controller In the capacity detection process, the charging of the charging target battery at a constant charging current value and the disconnection of the charging target battery from the power supply unit are performed after a predetermined time has elapsed from the start of the disconnection. The remaining battery of the battery to be charged at the time of measuring any one of the plurality of open-circuit voltages based on at least one of the plurality of open-circuit voltages measured while performing measurement of the open-circuit voltage for the elephant battery And detecting the remaining capacity of the battery to be charged at the time of measuring the two open-circuit voltages based on two of the measured open-circuit voltages, and detecting the two remaining capacities The battery capacity is calculated based on the difference between the two, the total open time for the battery to be charged during the measurement of the two open-circuit voltages, and the charging current value in the capacity detection process . The “constant current charging” in this specification includes so-called multi-stage constant current charging in which the current value of the constant current is changed in multiple stages in the charging process.

Further, the charging apparatus according to claim 2, wherein, in the charging device according to claim 1 Symbol mounting, the power supply unit is configured to controllably charging voltage value during charging of the charging target cell, the power control unit, the After performing constant current charging, constant voltage charging is performed on the battery to be charged.

  According to the charging device of claim 1, the power supply control unit executes the capacity detection process prior to the start of the constant current charging process to detect the remaining capacity and the battery capacity of the battery to be charged, and the detected remaining power By setting the charging current value during constant current charging based on the capacity and battery capacity and the preset target charging time, the set target charging time regardless of the battery capacity of the battery to be charged The battery to be charged can be charged to a fully charged state.

Further, according to this charging apparatus, in the capacity detection process, the power supply control unit performs predetermined charging from the start of the detachment between charging the charging target battery at a constant charging current value and detaching the charging target battery from the power supply unit. The measurement of the open-circuit voltage for the battery to be charged after the elapse of time is repeated a plurality of times, and the charge-target battery at the time of measuring any one of the open-circuit voltages based on at least one of the measured open-circuit voltages By detecting the remaining capacity, it is possible to detect the remaining capacity in real time while charging the battery to be charged without wasting time for the capacity detection process. In addition, by measuring the open voltage and detecting the remaining capacity of the battery to be charged, it is possible to eliminate the influence of the internal resistance that occurs when measuring the charging voltage due to the battery shape, electrode structure and wiring. It is also possible to reduce the influence of overvoltage that rises rapidly near full charge.

Further, according to this charging apparatus, in the capacity detection process, the power supply control unit determines the remaining capacity of the battery to be charged at each measurement of the two open-circuit voltages based on two of the plurality of open-circuit voltages measured. Detecting the capacity by calculating the battery capacity based on the difference between the detected two remaining capacities, the total charging time for the battery to be charged while measuring the two open-circuit voltages, and the charging current value in the capacity detection process The battery capacity can be detected while charging the battery to be charged without wasting processing time.

In addition, according to the charging device of the second aspect , the power supply control unit executes the constant voltage charging process after executing the constant current charging process, so that the charge target battery in a state that is almost fully charged is more fully charged. While shifting to a close state, the current at the end of charging can be reduced to avoid overcharging, so that it is possible to prevent a decrease in the life of the battery to be charged.

  Hereinafter, the best mode of a charging apparatus according to the present invention will be described with reference to the accompanying drawings. In addition, the structure which charges a secondary battery (specifically lead acid battery) as an example of a charge object battery is given and demonstrated.

As shown in FIG. 1, the charging device 1 includes a power supply unit 2, a switch unit 3, a voltage measurement unit 4, a power supply control unit 5, a storage unit 6, and a time measuring unit 7, and an AC voltage Vi from an AC power supply 8 as an example. The DC voltage Vo is inputted to generate the DC voltage Vo and the secondary battery 9 whose battery capacity is unknown can be charged by outputting the DC voltage Vo.

  As an example, the power supply unit 2 is configured to include a power circuit (not shown) of a switching system (which may be a series system) and is input from the AC power supply 8 through the input terminals P1 and P2. The voltage Vi is converted into a DC voltage (which is also a charging voltage of the secondary battery 9) Vo, and the DC voltage Vo is output to the secondary battery 9 connected to the output terminals P3 and P4. In addition, the power supply unit 2 is configured to be able to control the voltage value of the charging voltage Vo under the control of the power supply control unit 5, and the current value of the output current (which is also a charging current for the secondary battery 9) Io Current value) is controllable.

  The switch unit 3 is configured by a relay, a semiconductor switch element such as a transistor, and the like, and is interposed between the power supply unit 2 and the output terminal P3. In addition, the switch unit 3 is electrically connected between the power supply unit 2 and the output terminal P3 under the control of the power supply control unit 5 and electrically connected between the power supply unit 2 and the output terminal P3. Transition to one of the off states (non-conducting state) to be disconnected. The voltage measuring unit 4 is connected between the output terminals P3 and P4, measures the voltage value of the charging voltage Vo (charging voltage value of the secondary battery 9), and outputs it as voltage data Dv to the power supply control unit 5.

  The power supply control unit 5 includes a CPU (not shown) and the like. In addition, the power supply control unit 5 charges the secondary battery 9 by executing a charging process according to the operation program stored in the storage unit 6. In this charging process, the power supply control unit 5 detects (calculates) a capacity of the secondary battery 9 (remaining capacity (hereinafter also referred to as “SOC”, also referred to as “SOC” and battery capacity) and battery capacity). Charging condition determination processing for determining charging conditions for charging the secondary battery 9 at constant current, constant current charging processing for operating the power supply unit 2 with constant current charging, and constant voltage charging processing for operating the power supply unit 2 with constant voltage charging Execute. Moreover, the power supply control part 5 also performs the on-off control process with respect to the switch part 3 by outputting control signal S2.

  The storage unit 6 is configured by a semiconductor memory such as a ROM or a RAM. The storage unit 6 also includes an operation program for the power supply control unit 5, a remaining capacity calculation formula (the following formula (1)), a battery capacity calculation formula (the following formula (2)), and a target voltage of the secondary battery 9. Vt and the remaining capacity (as an example, 95%) of the secondary battery 9 when the charging voltage Vo increased by charging reaches the target voltage Vt for the first time are stored in advance. In addition, the storage unit 6 includes data D0 that defines a preset target charging time T0 of the secondary battery 9 (target time from the start of charging to completion of charging; 16 hours as an example), and an on / off control process for the switch unit 3 Data D1 and D2 that respectively define an on-time T1 (15 minutes as an example) and an off-time T2 (5 minutes as an example), and data D3 that defines a constant voltage charging process time T3 (2 hours as an example) Is stored in advance as timing data Dt for the timing unit 7. The storage unit 6 stores the number of times (as an example, a numerical value “3”) for measuring the charging voltage Vo of the secondary battery 9 in the capacity detection process. Further, the storage unit 6 includes a charging current value I1 (5A as an example) of the charging current Io in the capacity detection process, and a reference value (80% as an example) for the remaining capacity calculated based on the formula (1). Is stored in advance.

Remaining capacity (SOC) = A x Vop-B (1)
Here, A and B are constants (secondary batteries having different battery capacities) for the secondary battery 9 that are uniquely determined by the temperature at the time of charging (in this example, room temperature (25 ° C.) as an example). (Constant common to the secondary battery 9) . Vop is an open circuit voltage of the secondary battery 9. According to this equation (1), there is a proportional relationship between the remaining capacity (SOC) and the open circuit voltage Vop. The proportional relationship between the two is the secondary battery 9 left for a long time. In the short period immediately after the start of charging, the open circuit voltage Vop often deviates from the proportional relationship and shows a low value. However, in the charging period after this short period, the secondary battery 9 has a constant current at a constant temperature. 2 between the open-circuit voltage Vop [V] and the remaining capacity (SOC) [%] of the secondary battery 9 under the condition that the battery is continuously supplied (or a constant current is periodically supplied at regular intervals). It has been experimentally confirmed that the proportional relationship shown exists. For this reason, for A and B, at the operating temperature of the charging device 1 (which is also the temperature when charging the secondary battery 9), the open-circuit voltage Vop [ V] and the remaining capacity (SOC) [%] can be determined by measuring (experimenting) in advance. Moreover, the open circuit voltage Vop of the secondary battery 9 means the charging voltage (terminal voltage) of the secondary battery 9 when the switch unit 3 is shifted to the off state.

Battery capacity = I1 × ΔT × 100 / (SOC2-SOC1) (2)
Here, I1 is the charging current value of the charging current Io in the capacity detection process (in this example, 5A as described above), and (SOC2-SOC1) is the difference between the two remaining capacities SOC2 and SOC1 detected at an interval. (Unit is%). ΔT is the charge current Io to the secondary battery 9 from the time when the first remaining capacity SOC1 of the two remaining capacities SOC2 and SOC1 is detected to the time when the last remaining capacity SOC2 is detected. It is the sum total of charging time (total charging time in the present invention, the unit is time).

  When the time data 7 is input from the power controller 5, the timer 7 measures the time specified by the time data Dt, and when the specified time has elapsed, the power controller 5 In response to this, a timing completion signal S1 is output.

  Next, operation | movement of the charging device 1 is demonstrated with reference to FIGS.

  First, when the charging device 1 is activated in a state where the secondary battery 9 is connected between the output terminals P3 and P4, the voltage measuring unit 4 starts measuring the charging voltage value for the secondary battery 9. Then, output of the voltage data Dv to the power supply control unit 5 is started. Further, the power control unit 5 starts a charging operation for the secondary battery 9.

  In this charging operation, the power supply controller 5 first executes a capacity measurement process (remaining capacity detection process and battery capacity detection process) as shown in FIG. In this capacity measurement process, the power supply controller 5 first executes a remaining capacity detection process to detect the remaining capacity of the secondary battery 9 (step 51). In this remaining capacity detection process, as shown in FIG. 5, the power supply control unit 5 first sets the charging current value I1 of the charging current Io in the capacity measurement process stored in the storage unit 6 to the power supply unit 2. Then, the power supply unit 2 is operated (step 61). Thereby, when the secondary battery 9 is connected via the switch part 3, the power supply part 2 transfers to the state which can supply the charging current Io with respect to the secondary battery 9 with the charging current value I1.

  Next, the power supply control unit 5 outputs the control signal S2 to the switch unit 3 to shift the switch unit 3 to the ON state (step 62). As a result, the charging current Io starts to be supplied from the power supply unit 2 to the secondary battery 9 via the switch unit 3 at a constant current value (charging current value I1), and charging of the secondary battery 9 (constant current charging) is started. Be started. In addition, the power supply control unit 5 sets the data D1 (15 minutes) stored in the storage unit 6 as the timing data Dt in the timing unit 7 in synchronization with the timing of switching the switch unit 3 to the ON state. Then, the time measuring unit 7 starts measuring 15 minutes (step 63). Next, the power supply control unit 5 repeatedly detects whether or not the timing completion signal S1 has been input, thereby detecting whether or not the 15-minute timing by the timing unit 7 has been completed (step 64).

  Thereafter, the time measuring unit 7 completes the time measurement for 15 minutes, generates a time measurement completion signal S1, and outputs the signal to the power supply control unit 5. As a result, the power supply control unit 5 detects the completion of the 15-minute timing by the timing unit 7 in step 64, and then stops outputting the control signal S2 to the switch unit 3 and turns off the switch unit 3. (Step 65). Thereby, since the secondary battery 9 is disconnected from the power supply unit 2, the charging of the secondary battery 9 is stopped. Further, the power supply control unit 5 sets the data D2 (5 minutes) stored in the storage unit 6 to the time measuring unit 7 as time measuring data Dt in synchronization with the timing of shifting the switch unit 3 to the OFF state. Then, the time measuring unit 7 starts measuring 5 minutes (step 66). Next, the power supply control unit 5 repeatedly detects whether or not the timing completion signal S1 has been input, thereby detecting whether or not the 5-minute timing by the timing unit 7 has been completed (step 67).

  Thereafter, the time measuring unit 7 completes the time measurement for 5 minutes, generates a time measurement completion signal S1, and outputs the signal to the power supply control unit 5. Thereby, the power supply control part 5 detects completion of time measurement of 5 minutes by the time measuring part 7 in step 67, and then measures the charging voltage value of the secondary battery 9 (step 68). Specifically, the power supply controller 5 determines the charging voltage value of the secondary battery 9 based on the voltage data Dv (voltage data Dv input first after inputting the timing completion signal S1) when the timing completion signal S1 is input. Is stored in the storage unit 6. In this case, the measured charging voltage value of the secondary battery 9 is measured when the switch unit 3 is in an off state, that is, when the secondary battery 9 is disconnected from the power source unit 2. The open-circuit voltage Vop is a voltage value (open-circuit voltage value), and a charge voltage value (open-circuit voltage value) after 5 minutes (a predetermined time in the present invention) has elapsed since disconnection. The power supply controller 5 repeats the above steps 62 to 69 while determining whether or not the number of measurement of the charging voltage value for the secondary battery 9 has reached 3 (step 69). Are measured three times, and are sequentially stored in the storage unit 6 as the open-circuit voltage values Vop1, Vop2, and Vop3 of the secondary battery 9.

  Next, the power control unit 5 calculates the remaining capacity of the secondary battery 9 (step 70). In calculating the remaining capacity, the power supply control unit 5 first shows a straight line L (relationship between the charging time and the charging voltage Vo) in which the measured open-circuit voltage values Vop1, Vop2, and Vop3 are indicated by a one-dot chain line in FIG. Make sure it is on the straight line. In this example, as described above, each open-circuit voltage value Vop1, Vop2, Vop3 is measured every 20 minutes (= 15 minutes + 5 minutes) (at equal time intervals), and in the secondary battery 9, particularly a lead storage battery, Under the condition that a constant current is continuously supplied to the secondary battery 9 (or the constant current is periodically supplied at the same time) in the charging period excluding a predetermined period (for example, several minutes) immediately after the start of charging. It has been experimentally confirmed that there is a relationship in which the open circuit voltage Vop [V] of 9 increases in proportion to time. In this example, since charging is performed for 15 minutes from the start of charging, all open-circuit voltage values Vop1, Vop2, and Vop3 are positioned on the straight line L.

  After confirming that each open-circuit voltage value Vop1, Vop2, Vop3 is located on the straight line L, the power supply control unit 5 uses the above formula (1) to measure the last open-circuit voltage value Vop3. The remaining capacity of the secondary battery 9 is calculated and stored in the storage unit 6. In this example, as an example, it is assumed that the calculated remaining capacity is 40%. Thereby, the remaining capacity detection process is completed.

  Next, as shown in FIG. 4, the power supply control unit 5 compares the reference value (80%) for the remaining capacity read from the storage unit 6 with the calculated remaining capacity (40%) (step 52). When the remaining capacity is greater than or equal to the reference value, the process proceeds to a constant voltage charging process (step 57) in which the current is limited, and when the remaining capacity is less than the reference value, the process proceeds to the battery capacity detection process (step 53). In this example, since the remaining capacity is less than the reference value, the process proceeds to step 53 to execute the battery capacity detection process.

  In this battery capacity detection process, the power supply controller 5 first calculates the remaining capacity (SOC1) of the secondary battery 9 at the time when the first open-circuit voltage value Vop1 is measured using the above formula (1). And stored in the storage unit 6. In this example, as an example, it is assumed that the calculated remaining capacity is 35%. Next, the power supply control unit 5 calculates the battery capacity of the secondary battery 9 using the above equation (2). In this case, the remaining capacity (40%) of the secondary battery 9 calculated in step 51 is used as the SOC2. ΔT is the charge current Io to the secondary battery 9 from the time when the first remaining capacity SOC1 of the two remaining capacities SOC2 and SOC1 is detected to the time when the last remaining capacity SOC2 is detected. The total supply time (unit: time) is 30 minutes (0.5 hours) in this example. The charging current value I1 of the charging current Io in the capacity detection process is 5A. Therefore, the calculated battery capacity of the secondary battery 9 is 50 Ah. The power supply control unit 5 stores the calculated battery capacity (50 Ah) of the secondary battery 9 in the storage unit 6 and ends the battery capacity detection process.

  Next, the power supply control unit 5 executes a charging condition determination process (step 54). In this charging condition determination process, the power supply control unit 5 determines (specifies) the charging current value I2 of the charging current Io supplied from the power supply unit 2 to the secondary battery 9 in the constant current charging process. Specifically, the power supply control unit 5 firstly, the time (1 hour) required for the capacity measurement process, the target charging time T0 (16 hours) stored in the storage unit 6 and the time of the constant voltage charging process ( 2 hours), the time for executing the constant current charging process is calculated. In this case, this time is 13 hours (= 16− (2 + 1)). Next, the power supply controller 5 sets the remaining capacity (40%) of the secondary battery 9 at the time when the capacity measurement process is finished and the time when the constant current charge process is finished (the charging voltage Vo is first set to the target voltage Vt). From the remaining capacity (95%) of the secondary battery 9 at the time of reaching (at the time reached) and the calculated battery capacity (50 Ah), the charging capacity to be charged by the constant current charging process is calculated. In this case, the charge capacity is 27.5 Ah (= 50 Ah × (95% -40%) / 100). Finally, the power supply control unit 5 determines the charging current value I2 by dividing the calculated charging capacity (27.5 Ah) by the time for executing the constant current charging process (13 hours). In this case, the charging current value I2 is 2.11 A (= 27.5 Ah / 13 hours).

  Then, the power supply control part 5 performs a constant current charge process. In this constant current charging process, the power supply control unit 5 sets the charging current value I2 (2.11A) determined in the charging condition determination process in the power supply unit 2, thereby providing a constant current value ( The constant current charging in 2.11A) is started (step 55). In addition, the power supply control unit 5 sets data about the time (13 hours) for executing the constant current charging process in the time measuring unit 7 as time measuring data Dt in synchronization with the timing of starting the constant current charging process. The timing of 13 hours by the timing unit 7 is started. Each process in step 70 and steps 52, 53, and 54 is performed by the power supply control unit 5 in a very short time (1 second or less). Therefore, the constant current charging process is executed immediately after the capacity measurement process is completed, as shown in FIG. Thereafter, the power supply control unit 5 repeatedly detects whether or not the constant current charging time has reached 13 hours (set time T4) by detecting whether or not the timing completion signal S1 is input (step 56). Continue the constant current charging process.

  When the elapsed time from the start of the constant current charging process reaches 13 hours (set time T4), the timer unit 7 outputs a timing completion signal S1 to the power supply controller 5. The power supply controller 5 detects the input of the timing completion signal S1 in step 56, ends the constant current charging process, and then starts the constant voltage charging process (step 57). Through the constant current charging process for 13 hours, the charging voltage Vo of the secondary battery 9 reaches the target voltage Vt, and the remaining capacity of the secondary battery 9 reaches 95%.

In the constant voltage charging process, the power supply control unit 5 sets the target voltage Vt for the power supply unit 2 . Thereby, the power supply unit 2 starts a constant voltage charging operation for supplying the charging current Io to the secondary battery 9 while maintaining the charging voltage Vo at the target voltage Vt. In addition, the power supply control unit 5 reads the time T3 (2 hours) of the constant voltage charging process from the storage unit 6 in synchronization with the start timing of the constant voltage charging process, and sets the time measuring unit 7 as the time measuring data Dt. Then, the time counting unit 7 starts time counting for 2 hours. Thereafter, the power supply control unit 5 repeatedly detects whether or not the constant voltage charging time has reached 2 hours (time T3) by detecting whether or not the timing completion signal S1 is input (step 58). Continue the voltage charging process.

  When the elapsed time from the start of the constant voltage charging process reaches 2 hours (time T3), the timer 7 outputs a timing completion signal S1 to the power supply controller 5. In step 58, the power supply controller 5 detects the input of the timing completion signal S1, and ends the constant voltage charging process. Thereby, the charging operation for the secondary battery 9 is completed in 16 hours.

  Thus, according to this charging apparatus 1, the power supply control part 5 performs a capacity | capacitance detection process prior to the start of a constant current charge process, and the remaining capacity of the secondary battery 9 (immediately before the start of a constant current charge process). Remaining capacity) and battery capacity, and based on the detected remaining capacity and battery capacity and a preset target charging time T0, the charging current value in the constant current charging process (during constant current charging) is determined. Therefore, regardless of the battery capacity of the secondary battery 9, the secondary battery 9 can be charged to a fully charged state at the set target charging time T0 to complete the charging operation.

  Further, according to the charging device 1, in the capacity detection process, the power supply control unit 5 performs charging of the secondary battery 9 with a constant charging current value I1 and disconnection of the secondary battery 9 from the power supply unit 2. The measurement of the open-circuit voltages Vop1, Vop2, and Vop3 for the secondary battery 9 after the elapse of a predetermined time (5 minutes) from the start of the separation is repeated a plurality of times (as an example, three times), and the measured plurality of open-circuit voltages Vop1 , Vop2 and Vop3, the remaining capacity of the secondary battery 9 at the time of measuring any one of the open-circuit voltages Vop1, Vop2 and Vop3 is detected, thereby wasting the capacity detection processing time. The remaining capacity can be detected in real time while charging the secondary battery 9 without any problem. In addition, by measuring the open voltage Vop1, Vop2, Vop3 and detecting the remaining capacity of the secondary battery 9, the influence of the internal resistance generated when measuring the charging voltage due to the battery shape, electrode structure and wiring Can be eliminated, and the influence of the overvoltage that rapidly increases in the vicinity of the full charge can be reduced.

  Further, according to the charging device 1, in the capacity detection process, the power supply control unit 5 uses the two open voltages (open in this example) based on two of the plurality of measured open voltages Vop1, Vop2, and Vop3. Remaining capacities SOC1 and SOC2 of the secondary battery 9 at each measurement of the voltages Vop1 and Vop3) are detected, and the difference between the detected two remaining capacities (SOC2-SOC1) and the secondary battery during the measurement of the two open-circuit voltages By calculating the battery capacity based on the total charging time for 9 and the charging current value I1 in the capacity detection process, the battery capacity can be increased while charging the secondary battery 9 without wasting the time of the capacity detection process. Can be detected.

  Moreover, according to this charging device 1, after the power supply control part 5 performs a constant current charge process, a constant voltage charge process is performed only for a fixed time (in this example, 2 hours), so that the battery is almost fully charged. While the secondary battery 9 is shifted to a state close to full charge, the charging current value I1 at the end of charging can be reduced to avoid overcharging, so that the life of the secondary battery 9 can be prevented from being reduced. .

  In addition, this invention is not limited to above-described embodiment, The structure can be changed suitably. For example, the example in which only the formula (1) composed of the constants A and B at normal temperature (25 ° C.) is stored in the storage unit 6 has been described above, but the constants A and B at a plurality of temperatures are calculated by experiment. It is also possible to adopt a configuration that can be stored in the storage unit 6 and that the expression (1) to be used can be selected in accordance with the use temperature of the charging device 1 (the temperature when the secondary battery 9 is charged). Similarly, the target voltage Vt of the secondary battery 9, the remaining capacity (95%) of the secondary battery 9 when the charging voltage Vo increased by charging first reaches the target voltage Vt, the target of the secondary battery 9. Charge time T0 (16 hours), ON time T1 (15 minutes) and OFF time T2 (5 minutes) for the switch unit 3, constant voltage charging process time T3 (2 hours), and the secondary battery 9 in the capacity detection process Each of the number of measurements of the charging voltage Vo (three times), the charging current value I1 (5A) of the charging current Io in the capacity detection process, and the reference value (80%) for the remaining capacity calculated based on the formula (1) A plurality of values can also be stored in the storage unit 6 and arbitrarily selected. Further, although not shown, it is possible to employ a configuration in which an operation unit such as an operation panel or a keyboard is provided, and these values can be arbitrarily set.

  As a most preferable example, the remaining capacity of the secondary battery 9 calculated based on the open circuit voltage value Vop3 detected last in the capacity measurement process, that is, the remaining capacity of the secondary battery 9 immediately before starting the constant current charging process. As described above, the charging current value I2 in the constant current charging process is determined using the above, but the charging time (on time T1 of the switch unit 3) to the secondary battery 9 in the capacity measurement process is short. Thus, when the increase in the charging voltage Vo for the secondary battery 9 in one charging time is small, that is, when the increase in the remaining capacity of the secondary battery 9 due to one charging is small, the last detected opening Instead of the voltage value Vop, the remaining capacity of the secondary battery 9 is measured based on the open circuit voltage value Vop detected one or more times before the last within an allowable range, and constant current charging is performed based on the remaining capacity. It can also determine the charging current value I2 during sense, almost the target charging time T0 in this case it is possible to charge the secondary battery 9.

  Further, as a preferable example, the configuration in which the constant voltage charging process is executed following the constant current charging process has been described above. However, when the constant voltage charging process does not need to be executed, the zero time is defined for the time T3 of the constant voltage charging process. By using the data D3 to be performed, the constant current charging process can be completed and the charging operation can be completed.

  In addition, the constant current charging process has been described with respect to the example in which the elapsed time from the start thereof reaches the set time T4 (13 hours in the above example), but this set time T4 is used to charge the secondary battery 9. Since it is also the time for the voltage Vo to reach the target voltage Vt (the remaining capacity reaches 95%), the charging voltage Vo is detected as the target voltage Vt while detecting the charging voltage Vo based on the voltage data Dv from the voltage measuring unit 4. It is also possible to employ a configuration in which the constant current charging process is terminated when it is reached.

It is a lineblock diagram of charging device 1 concerning an embodiment of the invention. It is a characteristic view which shows the relationship between the open circuit voltage Vop and remaining capacity. It is a characteristic view which shows each change with time progress of the charging current Io and the charging voltage Vo in a charging process. 4 is a flowchart for explaining a charging operation of a power supply control unit 5; It is a flowchart for demonstrating the remaining capacity detection process in FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Charging device 2 Power supply part 3 Switch part 4 Voltage measurement part 5 Power supply control part 6 Memory | storage part 7 Timekeeping part 9 Secondary battery I2 Charging current value at the time of constant current charging Io Charging current T0 Target charging time Vo Charging voltage

Claims (2)

E Bei a power supply unit configured to be able to control the charging current value during charging of the charging target cell, and a power control unit for executing the constant current charging to the charging target cell by controlling the power supply unit, before SL power control unit, the running capacitance detection process prior to the start of constant current charging, and detects the remaining capacity and the battery capacity of the charging target cell, a residual capacity and the battery capacity was the detected pre A charging device that defines a charging current value during the constant current charging based on a set target charging time ,
In the capacity detection process, the power control unit performs charging at a constant charging current value to the charging target battery and disconnecting the charging target battery from the power source unit after a predetermined time has elapsed from the start of the disconnection. The battery to be charged at the time of measuring any one of the plurality of open-circuit voltages based on at least one of the plurality of open-circuit voltages measured while performing measurement of the open-circuit voltage for the battery to be charged in And detecting the remaining capacity of the battery to be charged at each measurement of the two open-circuit voltages based on two of the measured open-circuit voltages, and detecting the detected 2 A difference between two remaining capacities, a total charge time for the battery to be charged during the measurement of the two open-circuit voltages, and the charge in the capacity detection process. Charging device for calculating the battery capacity based on the current value. The power supply unit is configured to be able to control a charging voltage value at the time of charging the battery to be charged,
The power control unit claim 1 Symbol placement of the charging device executes the constant voltage charging to the charging target cell after performing the constant current charging.

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