JP5811921B2 - Lead-acid battery charger - Google Patents

Description

  The present invention relates to a charging device for charging a lead storage battery.

  Lead-acid batteries are used as power sources for electric vehicles and the like. The lead storage battery is charged by the charging device when the amount of stored electricity decreases with discharge. By the way, when the number of times of charge in an insufficiently charged state that is not fully charged increases, the lead-acid battery becomes a state in which the active material of the positive electrode or the negative electrode is crystallized and is difficult to charge, leading to capacity deterioration. For this reason, in order to eliminate capacity deterioration, for example, refresh charging is performed in which a lead storage battery as disclosed in Patent Document 1 is overcharged.

JP 2003-163034 A

  In Patent Document 1, refresh charging is executed based on the number of times of charging. However, lead storage batteries can eliminate capacity deterioration by refresh charging, but if refresh charging is frequently performed, there is a risk that the life of the lead storage battery may be reduced due to lattice corrosion and liquid dying due to gas generation. For this reason, it is preferable that the refresh charging is appropriately performed.

  This invention was made paying attention to the problem which exists in such a prior art, The objective is to provide the charging device of the lead storage battery which can perform the refresh charge in a lead storage battery effectively. It is in.

  In order to solve the above-described problems, the invention according to claim 1 is a lead-acid battery charging device that controls charge of a lead-acid battery, a calculation unit that calculates a voltage displacement amount per hour during charging, and the calculation A comparison unit that compares the voltage displacement amount calculated by the unit with a reference displacement amount, and a charge control unit that executes refresh charging when the voltage displacement amount compared by the comparison unit exceeds the reference displacement amount. This is the gist.

  According to this, refresh charging is executed based on the voltage displacement amount of the lead storage battery at the time of charging. That is, refresh charging is performed based on the monitoring result by monitoring the actual state of the lead storage battery. For this reason, the refresh charge can be executed when the refresh charge is required as the state of the lead storage battery. Therefore, the refresh charge in the lead storage battery can be executed effectively.

Further, in the invention according to claim 1, before Kinamari battery is charged with a multi-stage constant current charging is performed, the comparison unit, the reference displacement amount a voltage displacement of the plurality of stages of the calculation unit has calculated The gist is to be compared with.

  According to this, in the multistage constant current charging, the execution timing of the refresh charge is determined based on the voltage displacement amount of a plurality of stages. Thereby, the timing which should perform refresh charge can be determined accurately. Therefore, the refresh charge in the lead storage battery can be executed more effectively.

The invention according to claim 2 is the charging device for the lead storage battery according to claim 1 , wherein the comparison unit sets the sum of the voltage displacement amounts of the plurality of stages as a comparison object with the reference displacement amount. And According to this, since the execution timing of the refresh charge is determined based on the sum of the voltage displacement amounts, the execution timing can be accurately determined by a simple method.

According to a third aspect of the invention, in the charging device of the lead-acid battery of claim 1, wherein the comparison unit, the average displacement amount of the voltage displacement amount of the plurality of stages be compared with the reference displacement amount Is the gist. According to this, since the execution timing of the refresh charge is determined based on the average displacement amount of the voltage displacement amount, the execution timing can be accurately determined by a simple method.

Invention of Claim 4 is a charging device of the lead storage battery as described in any one of Claims 1-3 , The measurement part which measures the battery temperature of the said lead storage battery is provided, The said comparison The gist of the unit is to change the reference displacement amount to be compared according to the battery temperature measured by the measurement unit. According to this, since the reference displacement amount is changed in view of the change in characteristics of the lead storage battery due to temperature change, the execution timing of the refresh charge can be determined with higher accuracy.

  ADVANTAGE OF THE INVENTION According to this invention, refresh charge can be effectively performed in a lead acid battery.

The block diagram which shows the structure of a charging device. The graph which shows the displacement of the voltage which may arise by repetition of charge. The graph which shows the displacement difference of a voltage. The flowchart which shows the determination process which determines charge mode. The flowchart which shows normal charge mode. The flowchart which shows refresh charge mode.

Hereinafter, an embodiment embodying the present invention will be described with reference to FIGS.
As shown in FIG. 1, the charging device 11 of the lead storage battery 10 includes a control unit 13 that controls charging. The lead storage battery 10 and the charging device 11 are connected via a power supply line L1. A wattmeter 12 is connected to the feeder line L1. The measurement result of the wattmeter 12 is transmitted to the charging device 11. In addition, the wattmeter 12 measures a voltage value and a current value. In addition, the charging device 11 is connected to the power system 14 via the feeder line L2. The charging device 11 receives power supplied from the power system 14. The power system 14 is a power transmission system for transmitting power and is owned by an electric power company. The lead storage battery 10 is charged by receiving power from the charging device 11. The lead storage battery 10 of this embodiment is a sealed lead storage battery.

  In the present embodiment, the control unit 13 controls the charging of the lead storage battery 10 using a multistage constant current charging method. Multi-stage constant current charging is a method in which charging is performed at a constant current and charging is performed by stepping down the current value every time the charging voltage reaches a predetermined voltage. In the present embodiment, the control unit 13 performs charging in five stages.

  When the number of times of charging in an insufficiently charged state that is not fully charged increases, the lead storage battery 10 becomes a state in which the active material of the positive electrode or the negative electrode is crystallized and is difficult to charge, resulting in capacity deterioration. And this capacity | capacitance degradation can be eliminated by performing the refresh charge which makes the lead storage battery 10 an overcharge state. However, if refresh charging is frequently performed, there is a risk that the life of the battery may be reduced due to lattice corrosion or liquid dying due to gas generation. For this reason, it is preferable to carry out refresh charging appropriately. Therefore, the charging device 11 of the present embodiment performs control to execute refresh charging at an appropriate timing.

FIG. 2 shows the characteristics of the voltage displacement when the lead storage battery 10 is charged with a multistage constant current.
A voltage waveform H1 indicated by a solid line in FIG. 2 is a voltage waveform when there is no capacity deterioration. The time when no capacity deterioration has occurred is after initial charging or after refresh charging. On the other hand, a voltage waveform H2 indicated by a one-dot chain line in FIG. 2 is a voltage waveform when charging is repeated for a predetermined number of cycles (several tens of cycles). Also, in the figure, “D1” indicates the first stage of multi-stage constant current charging, “D2” indicates the second stage, “D3” indicates the third stage, and “D4” indicates the fourth stage. .

  Comparing the voltage waveform H1 and the voltage waveform H2, when the capacity deterioration progresses with an increase in the number of charging cycles, the time to reach the predetermined voltage V in each stage of the multi-stage constant current charging becomes earlier. That is, when the capacity deterioration progresses, the displacement (slope) of the voltage waveform increases. For this reason, the control unit 13 of the charging device 11 calculates a voltage displacement amount for a certain period immediately before switching the current value of each stage of the multistage constant current charging, and the calculated voltage displacement amount is used as a predetermined reference displacement amount. When the threshold value α is exceeded, refresh charging is performed.

  FIG. 3 shows the voltage displacement amount (voltage difference [ΔV]) of each stage during a certain period. In addition, the waveform indicated by the solid line in the figure indicates the voltage displacement amount of each stage corresponding to the voltage waveform H1 in FIG. 2, and the waveform indicated by the alternate long and short dash line in the figure indicates the voltage displacement amount corresponding to the voltage waveform H2 in FIG. Indicates. Also, in the figure, “D1” indicates the first stage of multi-stage constant current charging, “D2” indicates the second stage, “D3” indicates the third stage, and “D4” indicates the fourth stage. . As shown in FIG. 3, at each stage, there may be a difference between the voltage displacement amount of the voltage waveform H1 and the voltage displacement amount of the voltage waveform H2. And the difference in the amount of voltage displacement increases as the number of stages increases. For this reason, when the above-described determination of necessity of refresh charging is performed based on, for example, the voltage displacement amount of the first-stage voltage waveform H2, the voltage displacement amount approximates the voltage displacement amount of the voltage waveform H1. It is hard to do. Therefore, it is desirable that the determination of whether or not the refresh charging is necessary is performed based on the voltage displacement amount of a large number of stages in order to perform an accurate determination. The accurate determination is a determination for effectively performing refresh charging.

  Hereinafter, the control content performed in order for the control part 13 of the charging device 11 to charge the lead acid battery 10 is demonstrated according to FIG. In this embodiment, the control part 13 which performs the following control content functions as a calculation part, a comparison part, and a charge control part.

  In the present embodiment, the control unit 13 performs multi-stage constant current charging including 1 to 5 stages by voltage detection and change of the current value. And the control part 13 will perform charge of the stage number Cx, if charge is started (step S10). “X” is assigned a number “1” to “5” indicating the first to fifth stages. When starting the charging, the control unit 13 sequentially detects the charging voltage of the lead storage battery 10 via the wattmeter 12. And the control part 13 determines whether the detected voltage reached | attained the predetermined voltage V by voltage detection (step S11). When this determination result is negative, that is, when the predetermined voltage V has not been reached, the control unit 13 continues to charge the current number of stages without changing the current value. That is, if the control unit 13 makes a negative determination in step S11, the control unit 13 returns to step S10 and continues charging the current number of stages.

  On the other hand, when the determination result of step S11 is affirmative, that is, when the predetermined voltage V is reached, the control unit 13 executes a process for starting charging the next number of stages. By this process, the current value is changed. In step S12, the control unit 13 changes the number of stages of charging to the next number of stages. In FIG. 4, the change in the number of charging stages is expressed as “x = x + 1”. That is, in this notation, for example, the current stage number is the first stage, and if affirmative determination is made in step S11, 1 is added to “1” to become “2 (= x)”, whereby the stage number is set to the first stage. Change to the 2nd row. In addition, the control unit 13 makes a positive determination in step S11 and stores the time when the number of steps is switched to the next number of steps.

  Next, the control unit 13 determines whether or not the number of stages to be charged is “5” (step S13). In step S13, the control unit 13 determines whether or not it is the last stage number of the multistage constant current charging. If this determination result is negative, that is, the number of stages is “2 to 4”, the control unit 13 returns to step S10 and starts charging the next number of stages. That is, the control unit 13 starts charging by switching the current value.

  On the other hand, when the determination result of step S13 is affirmative, that is, when the number of stages is “5”, the control unit 13 proceeds to step S14 and determines whether the final stage is set to the normal charge mode or the refresh charge mode. To do. In this determination, the control unit 13 first calculates a voltage displacement amount in each stage before the final stage. This voltage displacement amount is a voltage displacement amount for a certain period immediately before switching the current value of each stage. For this reason, the control part 13 calculates the voltage displacement amount (voltage difference / time difference) per time of each stage based on the time when switching with the detected charging voltage. Next, the control unit 13 calculates the total sum of the voltage displacement amounts of each stage, that is, 1 to 4 stages, as a calculated value Z, and compares the calculated value Z with a predetermined threshold value α. The threshold value α is a reference displacement amount that is determined to start refresh charging. This threshold value α is a fluctuation value determined according to the specification (for example, capacity) of the lead storage battery 10, and is set to an optimum value in simulation or the like. For example, when refresh charging is performed, the voltage characteristics may be set within a range in which the voltage characteristic returns to the voltage waveform H1.

  Then, the control unit 13 compares the threshold value α with the calculated value Z, and when the calculated value Z does not exceed the threshold value α, affirmative determination is made in step S14. In this case, the control unit 13 determines not to start refresh charging. Thereby, the control part 13 charges the last stage in normal charge mode (step S15). On the other hand, the control unit 13 compares the threshold value α with the calculated value Z. If the calculated value Z exceeds the threshold value α, the control unit 13 makes a negative determination in step S14. In this case, the control unit 13 determines to start refresh charging. Thereby, the control part 13 charges the last stage in refresh charge mode (step S16).

  When charging in the normal charging mode in step S15, the control unit 13 starts charging at the final stage as shown in FIG. 5 (step S20). Next, the control unit 13 determines whether or not the final charge amount of the lead storage battery 10 has reached the charge amount Wa (step S21). The charge amount in the final stage is calculated based on the detection result of the wattmeter 12 after starting the charge in the final stage. If the determination result in step S21 is negative, that is, if the final stage charge amount has not reached the charge amount Wa, the control unit 13 returns to step S20 and continues the final stage charge. On the other hand, when the determination result of step S21 is affirmative, that is, when the charge amount at the final stage reaches the charge amount Wa, the control unit 13 ends the charge at the final stage. Thereby, the control part 13 complete | finishes charge of the lead storage battery 10 based on multistage constant current charge.

  On the other hand, when charging in the refresh charging mode in step S16, the control unit 13 starts charging at the final stage as shown in FIG. 6 (step S30). Next, the control part 13 determines whether the last charge amount of the lead storage battery 10 has reached the charge amount Wb (step S31). The charge amount Wb is set to a larger amount than the charge amount Wa, which is a condition for ending charging in the normal charge mode. If the determination result in step S31 is negative, that is, if the final stage charge amount has not reached the charge amount Wb, the control unit 13 returns to step S30 and continues the last stage charge. On the other hand, when the determination result of step S31 is affirmative, that is, when the charge amount at the final stage reaches the charge amount Wb, the control unit 13 ends the charge at the final stage. Thereby, the control part 13 complete | finishes charge of the lead storage battery 10 based on multistage constant current charge. In the refresh charge mode, a charge amount Wb larger than that in the normal charge mode is set as the charge amount at the final stage, which is a charge termination condition. For this reason, the lead storage battery 10 is overcharged more than usual.

Next, the effect | action of the charging device 11 of this embodiment is demonstrated.
When charging of the lead storage battery 10 is started, the control unit 13 of the charging device 11 monitors the voltage displacement amount of each stage before the final stage. The control unit 13 performs refresh charging when the voltage displacement amount of each stage exceeds a certain displacement amount. Specifically, the control unit 13 performs refresh charging when the sum of the amount of voltage displacement at each stage exceeds the threshold value α. The lead-acid battery 10 after refresh charging returns to the voltage characteristics during charging as shown by the voltage waveform H1 shown in FIGS. In this embodiment, the timing for performing refresh charging is determined by actually monitoring the voltage characteristics of the lead storage battery 10 during charging. For this reason, it is possible to perform refresh charging at an appropriate timing.

Therefore, in this embodiment, the following effects can be obtained.
(1) The refresh charge is executed based on the voltage displacement amount of the lead storage battery 10 at the time of charge. That is, refresh charging is performed based on the monitoring result by monitoring the actual state of the lead storage battery 10. Thereby, it can be made to perform when the refresh charge is required as a state of the lead storage battery 10. Therefore, the refresh charge in the lead storage battery 10 can be executed effectively.

  (2) Since the refresh charge is performed by monitoring the state of the lead storage battery 10, the execution timing of the refresh charge can be optimized. As a result, the number of refresh charges can be set to a necessary number, that is, an appropriate number. Therefore, a phenomenon that can be caused by frequently performing refresh charging, that is, lattice corrosion or liquid withering due to gas generation, can be suppressed, and the life extension effect of the lead storage battery 10 can be expected.

  (3) Since the calculated value Z to be compared with the threshold value α is calculated based on the voltage displacement amounts in a plurality of stages, the timing at which refresh charging should be performed can be determined with high accuracy. That is, the refresh charge execution timing can be further optimized. Therefore, the refresh charge in the lead storage battery 10 can be executed more effectively.

(4) The calculated value Z is calculated as the sum of the voltage displacement amounts in a plurality of stages. Therefore, the refresh charging execution timing can be accurately determined by a simple method.
(5) Since the actual state of the lead storage battery 10 is monitored and refresh charging is executed based on the monitoring result, execution of the refresh charging can be automated. In other words, it is not necessary to leave the refresh charge to the user or owner of the lead storage battery 10. Therefore, the refresh charge can be effectively executed at the optimum timing.

(6) Since the life of the lead storage battery 10 can be extended by optimizing the execution timing of the refresh charge, it is possible to contribute to reducing the maintenance cost of the user and the owner of the lead storage battery 10.
In addition, you may change the said embodiment as follows.

The lead storage battery 10 may be either an in-vehicle lead storage battery or a stationary lead storage battery. Moreover, the lead storage battery 10 used for another use may be sufficient.
A temperature sensor 15 is provided in the lead storage battery 10 as shown by a two-dot chain line in FIG. Then, the control unit 13 is caused to function as a measurement unit that measures the battery temperature of the lead storage battery 10 from the detection result of the temperature sensor 15. Further, the control unit 13 stores map data in which the threshold value α is associated with the battery temperature. And the control part 13 sets the threshold value (alpha) compared with the calculated value Z in step S14 of FIG. 4 based on battery temperature. The characteristics of the lead storage battery 10 change due to temperature changes. For this reason, by preparing the threshold value α corresponding to the battery temperature and changing the threshold value α from the battery temperature at the time of charging, the execution timing of the refresh charge can be determined with higher accuracy. As a result, refresh charging can be executed more effectively.

  The calculated value Z may be an average displacement amount of a plurality of voltage displacement amounts. In this case, the threshold value α is also set to a value corresponding to the average displacement amount. According to this, as in the embodiment, it is possible to determine the execution timing of the refresh charge with a simple method with high accuracy.

○ When the lead storage battery 10 is charged by multistage constant current charging, the number of stages may be changed. For example, it may be 2 to 4 stages or 6 or more stages.
○ The number of stages in calculating the calculated value Z may be changed. For example, when performing multi-stage constant current charging of 5 stages as in the embodiment, the calculated value Z may be calculated from 2 to 4 stages of voltage displacement or 3 or 4 stages of voltage displacement. Further, instead of the number of continuous stages, the calculated value Z may be calculated from voltage displacement amounts of non-continuous stages such as 2 stages and 4 stages, for example. This alternative example can also be applied to the case where the above-described calculated value Z is calculated as an average displacement amount of a plurality of stages of voltage displacement amounts.

  In multi-stage constant current charging, it may be determined whether to perform refresh charging based on any one stage voltage displacement amount. For example, in the case of the embodiment, the voltage displacement amount at the third stage or the fourth stage may be the calculated value Z, and refresh charging may be executed when the threshold value α is exceeded. In this case, the threshold value α is also set to a value corresponding to the one-stage voltage displacement amount.

The charging method of the lead storage battery 10 may be a multistage constant current constant voltage method.
○ Instead of the wattmeter 12, a voltmeter or an ammeter may be used.
○ Termination conditions for the last stage of charging may be changed. For example, the end condition may be a voltage value (end voltage). In this case, the end voltage in the refresh charge mode is set higher than the end voltage in the normal charge mode. The end condition may be time. In this case, the time for ending the refresh charge mode is made longer than the time for ending the normal charge mode. In addition, since lengthening time is equivalent to increasing charge amount, when carrying out time management of charge completion, the structure which measures charge amount can be omitted. The termination condition when the charging method is a multistage constant current constant voltage may be the current value. In this case, the current value in the refresh charge mode is set higher than the current value in the normal charge mode.

  The charge termination condition determined in step S21 in FIG. 5 and step S31 in FIG. 6 may be the total charge amount after starting the first stage charge. That is, if the charge end condition is a case where the charge amount (SOC) of the lead storage battery 10 at the start of charging is detected, the total charge amount after the start of charging can be detected. The charging termination condition may be changed as follows. In this case, in the refresh charge mode, determination is made by setting a larger total charge amount than in the normal charge mode as a charge termination condition. As a result, the lead storage battery 10 is overcharged in the refresh charge mode than in the normal charge mode.

  DESCRIPTION OF SYMBOLS 10 ... Lead acid battery, 11 ... Charger, 13 ... Control part.

Claims (4)

In the lead-acid battery charger that controls the charge of the lead-acid battery,
A calculation unit for calculating a voltage displacement amount per time at the time of charging;
A comparison unit for comparing the voltage displacement amount calculated by the calculation unit with a reference displacement amount;
A charge control unit that performs refresh charging when the voltage displacement amount compared by the comparison unit exceeds a reference displacement amount , and
The lead storage battery is charged by multi-stage constant current charging,
The said comparison part makes the voltage displacement amount of the multistage calculated by the said calculation part the comparison object with the said reference displacement amount, The charging device of the lead storage battery characterized by the above-mentioned . 2. The lead-acid battery charging device according to claim 1 , wherein the comparison unit uses a sum of the plurality of voltage displacement amounts as a comparison target with the reference displacement amount. The lead-acid battery charging device according to claim 1 , wherein the comparison unit uses an average displacement amount of the plurality of stages of voltage displacement amounts as a comparison target with the reference displacement amount. A measurement unit for measuring the battery temperature of the lead storage battery,
The comparison unit, the charging device of the lead-acid battery according to any one of claims 1 to 3, characterized in that to change the reference displacement amount compared according to the battery temperature, wherein the measurement unit is measured .