JP2013037829A - Method for detecting internal short circuit of lead acid battery and power supply system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for simply and accurately detecting a lead acid battery which has generated internal short circuit, and to provide an excellent power supply system equipped with this detection method.SOLUTION: The method for detecting internal short circuit of the lead acid battery in which an electrode plate group consisting of a positive electrode plate, a negative electrode plate, and a separator is housed together with an electrolyte in a battery case consisting of a plurality of cell chambers is arranged by including: checking an actual value of a balanced current in a constant voltage charge of a target lead acid battery against a threshold value based on the balanced current of a lead acid battery which has not generated internal short circuit; and determining that the target lead acid battery has generated internal short circuit when the actual value is larger than the threshold value.

Description

  The present invention relates to a lead storage battery inspection method, and more particularly to a process for discharging defective products.

  In recent years, the global warming problem has attracted attention, and in driving a vehicle, there is a demand for a shift from an internal combustion engine such as a gasoline engine or a diesel engine to electricity that does not emit harmful exhaust gas components. Under these trends, the electrification of cars and forklifts is progressing rapidly. Lead storage batteries that are cheaper and easier to handle than nickel metal hydride storage batteries and lithium secondary batteries are widely used as the main power source for these electric vehicles and electric forklifts.

  In the lead acid battery, a defective product in which the positive electrode plate and the negative electrode plate are internally short-circuited may occur in the manufacturing process. As a method for discharging this defective product, a method is used in which the amount of change in the open circuit voltage is measured while left unloaded for a predetermined period, and a lead storage battery having a large amount of change in the same lot is determined as a defective product. Among them, the method of Patent Document 1 is a method for detecting defective products from the distribution of the open circuit voltage of a lead storage battery measured after being left under a predetermined condition in a discharged state, and is described as being capable of detecting minute internal short circuits. Yes. The method of Patent Document 2 is a method of detecting a defective product from a voltage difference between a plurality of cells constituting a lead storage battery. When only one cell is short-circuited (other cells are non-defective), lead is used. Although it is difficult to detect the open circuit voltage of the storage battery because it is the total value of the voltages of these cells, it is described that even a minute internal short circuit can be accurately detected in cell units.

Japanese Patent Laid-Open No. 05-144478 JP 2007-103112 A

  However, the conventional methods including Patent Documents 1 and 2 require a long standing period in order to determine a defective product causing an internal short circuit. In particular, the method of Patent Document 2 is complicated because the voltage of each cell of the lead storage battery is measured.

  Also, the open circuit voltage of the lead-acid battery decreases due to self-discharge that is unrelated to the internal short circuit. Since the amount of self-discharge of a lead storage battery is affected by the state of charge, all the states of charge need to be the same for quantification. In addition, the open circuit voltage behavior is unstable because the diffusion polarization of the electrolyte remains immediately after charging and discharging, and the conventional method cannot accurately separate the voltage drop due to self-discharge and the voltage drop due to short-circuit discharge. There are various difficulties.

  The present invention is for solving the above-described problems, and an object thereof is to provide a method for easily and accurately detecting a lead-acid battery that has caused an internal short circuit, and a high-quality power supply system incorporating this detection method. And

  In order to solve the above-mentioned problems, the invention according to claim 1 of the present invention is configured such that an electrode plate group including a positive electrode plate, a negative electrode plate, and a separator is housed in a battery case including a plurality of cell chambers together with an electrolyte. An internal short-circuit detection method for a lead-acid battery, in which the measured value of the equilibrium current in constant-voltage charging of the target lead-acid battery is collated with a threshold value based on the balanced current of the lead-acid battery that does not cause an internal short-circuit, When the value is larger than the threshold value, it is determined that the target lead-acid battery has caused an internal short circuit.

  The invention according to claim 2 is characterized in that, in claim 1, the charging voltage in the constant voltage charging is set to 2.22 to 2.37 V per lead acid battery cell.

  The invention according to claim 3 is individually connected to a power storage unit having at least one series circuit composed of one or more lead storage batteries, a power source unit for charging the power storage unit at a constant voltage, and each series circuit. A series circuit that compares the measured current value and the measured value of the balanced current measured by the current measuring unit with the current measured by the current measuring unit against the threshold value based on the balanced current of the lead-acid battery that does not cause an internal short circuit. If there is a determination unit that determines that there is a lead storage battery causing an internal short circuit in this series circuit, and a series circuit that includes a lead storage battery that causes an internal short circuit, follow the instructions of the determination unit The present invention relates to a power supply system including a notification unit that identifies and notifies the series circuit.

  The invention according to claim 4 is characterized in that, in claim 3, the charging voltage in the constant voltage charging is set to 2.22 to 2.37 V per one lead storage battery cell in one series circuit.

  In the invention according to claim 5, when there is a series circuit having a lead-acid battery causing an internal short circuit in claim 3, the series circuit is opened, and a charging current corresponding to the number of opened series circuits is provided. The determination unit is provided with a function for instructing the power supply unit to attenuate.

  The invention according to claim 6 is characterized in that, in claim 5, the determination unit has a function of notifying the notification unit that the series circuit having the lead storage battery causing the internal short circuit is opened. To do.

  In the invention according to claim 7, when there is a series circuit having a lead storage battery causing an internal short circuit in claim 3, the series circuit is opened and each lead storage battery constituting the opened series circuit is opened. The determination unit has a function of identifying a lead storage battery causing an internal short circuit by measuring an open circuit voltage and notifying the notification unit.

  The invention according to claim 8 is individually connected to a power storage unit having at least one series circuit composed of one or more lead storage batteries, a power supply unit for charging the power storage unit at a constant voltage, and each series circuit. A series circuit that compares the measured current value and the measured value of the balanced current measured by the current measuring unit with the current measured by the current measuring unit against the threshold value based on the balanced current of the lead-acid battery that does not cause an internal short circuit. When there is a battery, it is determined that there is a lead-acid battery causing an internal short circuit in this series circuit, and this series circuit is opened and the power supply is attenuated in accordance with the number of opened series circuits. The present invention relates to a power supply system including a determination unit that instructs the unit.

  The invention according to a ninth aspect is characterized in that, in the eighth aspect, the charging voltage in the constant voltage charging is set to 2.22 to 2.37 V per one lead storage battery cell in one series circuit.

  Lead storage batteries have fewer side reactions that occur at the end of charging than other battery systems, although depending on the set upper limit voltage. The inventors who focused on this foresee that the lead-acid battery that caused an internal short circuit has an equilibrium current at the end of constant voltage charging that is smaller than the balance current of a lead-acid battery that does not cause an internal short circuit, and has demonstrated this. We were able to. The present invention has been made on the basis of this verification result, and measured the equilibrium current in constant voltage charging of the target lead-acid battery, and based on the measured current value based on the equilibrium current of the lead-acid battery not causing an internal short circuit. When the measured value is larger than the threshold value, it is determined that the target lead storage battery has caused an internal short circuit.

  By utilizing this short-circuit detection method, as will be described in detail later, the presence or absence of an internal short circuit of the lead storage battery constituting itself is determined during charging, and if there is an internal short circuit, there is a corresponding lead storage battery Therefore, it is possible to configure a power supply system that can notify the above and eliminate the lead storage battery.

  ADVANTAGE OF THE INVENTION According to this invention, the method of detecting the lead storage battery which caused the internal short circuit simply and accurately, and the quality power supply system which incorporated this detection method can be provided now.

Partial perspective view of a lead-acid battery used in the present invention (A) The figure which shows the equilibrium current in the constant current charge of lead acid battery, (b) The figure which shows the principal part The block diagram which shows an example of the power supply system of this invention The flowchart which shows an example of operation | movement of the power supply system of this invention

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings.

  FIG. 1 is a partial perspective view of a lead-acid battery used in the present invention. The positive electrode plate 1a and the negative electrode plate 1b are opposed to each other through the separator 1c to produce the electrode plate group 1, and each of the battery cases 2 partitioned into a plurality (mainly six) cell chambers 2b by the intermediate partition plate 2a. The electrode plate group 1 is accommodated in the cell chamber 2b. In the same cell chamber 2 b, the ears of the positive electrode plate 1 a are collectively connected to one strap 3, and the ears of the negative electrode plate 1 b are collectively connected to the other strap 3. Then, the positive strap 3 and the negative strap 3 are connected in series using the connection component 4, and the straps 3 at both ends not connected to the other polarity strap 3 are connected to the pole column. Furthermore, the opening part of the battery case 2 is sealed by the lid 5 having a liquid port, and the pole columns connected to the electrode plate group 1 at both ends are fitted into the bushings to be integrated into the terminal 6. Finally, after injecting the electrolytic solution (dilute sulfuric acid) from the liquid port, the liquid port is closed by the liquid port plug 5a, thereby forming a lead storage battery.

  FIG. 2 (a) is a diagram showing the equilibrium current when the lead-acid battery (6-cell series type) of FIG. 1 is charged at a constant current of 13.7V, and FIG. 2 (b) is its main part (indicated by A in the figure). ). Usually, when charging a lead storage battery with a charger such as an alternator, constant current charging is performed up to a set upper limit voltage, and then constant voltage charging is performed using the set upper limit voltage as a charge voltage. When constant voltage charging is continued, there is a region (A) in which the current is attenuated and becomes constant. The current in this region is called the equilibrium current.

  The inventor has paid attention to the fact that the lead-acid battery has fewer side reactions that occur at the end of charging than other battery systems, although it depends on the set upper limit voltage. And the lead storage battery which caused the internal short circuit predicted that the equilibrium current at the end of the constant voltage charge was smaller than the equilibrium current of the lead storage battery which did not cause the internal short circuit. On top of that, a lead storage battery A in which an internal short circuit is intentionally caused and lead storage batteries 2 to 4 in which it has been confirmed in advance that no internal short circuit has occurred are prepared, and the constant current-constant pattern having the pattern shown in FIG. Voltage charging was performed. As a result, as shown in FIG. 2 (b), the lead storage batteries 2 to 4 in which no internal short circuit has occurred are only currents that compensate for the self-discharge consumption (10 to 20 mA), but an internal short circuit has occurred. The lead-acid battery A is also applied with a current (40 to 45 mA) that supplements the consumption of the internal short circuit, so that it was proved that the equilibrium current is large with a significant difference.

  The present invention has been made on the basis of this verification result. As a specific example, the threshold value of the equilibrium current when there is no internal short circuit (for example, the average value of the equilibrium currents of the lead storage batteries 2 to 4) If the measured current value is larger than the threshold value, the equilibrium current in the constant voltage charging of the target lead storage battery is measured, and this measured value is compared with the threshold value. It is determined that the target lead-acid battery is causing an internal short circuit.

  If this internal storage short-circuit detection method is used, in addition to discharging the internal storage short-circuited lead storage battery in the manufacturing process, the internal structure of the lead storage battery that constitutes itself during charging is as follows. Whether or not there is a short circuit is determined, and when there is an internal short circuit, it is possible to notify that there is a corresponding lead storage battery or to configure a power supply system that can eliminate this lead storage battery.

  FIG. 3 is a block diagram showing an example of a power supply system according to the present invention, and shows a mode in which charging can be clearly distinguished from operation in which only discharging is performed, as in an electric vehicle. FIG. 4 is a flowchart showing an example of the operation of the power supply system of FIG.

  The power supply system 11 includes a power storage unit composed of series circuits 12a, 12b and 12c composed of one or more lead storage batteries, and a power supply unit 13 for charging the power storage unit at a constant voltage. During operation, the switch 17 connects the load 19 (such as a motor of an electric vehicle) and the power storage unit, and discharges the lead storage battery constituting the power storage unit. During charging, the switch 17 connects the power supply unit 13 and the power storage unit to charge the lead storage battery. At this time, the power supply system of the present invention performs the following operation.

  After performing constant current charging of the lead storage battery constituting the power storage unit up to the set upper limit voltage of the power supply unit 13, when the power supply unit 13 starts constant voltage charging in step S01, each series circuit 12a, 12b and 12c in step S02. The current measuring units 14a, 14b, and 14c (indicated as shunt resistors in FIG. 3) individually connected to each start measurement of the charging current value. Subsequently, in step S03, it is determined whether or not each of the series circuits 12a, 12b and 12c has reached an equilibrium current from the change with time of the charging current. Here, “having reached the equilibrium current” is determined, for example, by the fact that the fluctuation width of the charging current (difference between the upper limit peak value and the lower limit peak value) did not change over 5 mA for 360 minutes. In step S04, the determination unit 15 that stores a threshold value based on the equilibrium current of the lead storage battery that has not caused an internal short circuit obtains the data of the equilibrium current measured by the current measurement units 14a, 14b, and 14c, and compares this data with this threshold value. It is then determined whether each equilibrium current is greater than a threshold value. Here, the threshold value stored in the determination unit 15 can be based on an equilibrium current that is clearly not internally short-circuited, such as the lead storage batteries 2 to 4 in FIG.

  If it is determined in step S04 that none of the series circuits 12a, 12b, and 12c has a measured value of the equilibrium current larger than the threshold value, all of the power storage units (series circuits 12a, 12b, and 12c) are normal products in step S08. determination is made, continue to continue charging.

  In the determination in step S04, if any of the series circuits 12a, 12b and 12c has a measured value of the balanced current larger than the threshold value (assuming that the series circuit 12a corresponds here), in step S05, The determination unit 15 determines that there is a lead storage battery causing an internal short circuit in the series circuit 12a. In step S06, the determination unit 15 instructs the notification unit 16 to notify that there is a lead storage battery causing an internal short circuit in the series circuit 12a, and the notification unit 16 notifies the fact according to this instruction. Here, the notification unit 16 can take various forms. As an example, the lamp can be turned on or blinked as the notification unit 16. As another example, a buzzer or an artificial voice device can be used as the notification unit 16 to output a warning sound or a voice such as “series circuit 12a is abnormal”. As yet another example, a notification that the series circuit 12a is abnormal can be left in a visual appeal by using a screen such as a liquid crystal as a notification unit 16 and a message such as “The series circuit 12a is abnormal”.

  Further, in the forms of FIGS. 3 and 4, the series circuit 12a is opened by turning off the switch 18a in accordance with an instruction from the determination unit 15 in step S07. If the determination unit 15 has a function of notifying the notification unit 16 by a message such as “The series circuit 12a is abnormal and the number of series is reduced by one” or the like indicating that the series circuit 12a is open. It is more preferable because the user can quickly know that the decrease in the discharge capacity is due to the abnormality of the series circuit 12a and perform maintenance such as repair.

  Here, the series circuit 12a where the lead storage battery causing the internal short circuit is opened is opened, and the open circuit voltage of each lead storage battery constituting the series circuit 12a is measured by a voltage measuring unit (not shown). The determination unit 15 is identified and the determination unit 15 is identified, and the notification unit 16 notifies the message such as “the second lead storage battery from the right of the series circuit 12a is abnormal” according to the instruction of the determination unit 15. If so, the user can recognize the lead storage battery to be replaced, which is more preferable.

  FIGS. 3 and 4 show claims 5 to 7 of the present invention. However, the notification unit 16 only notifies that the series circuit 12a is causing an internal short circuit (claim 3), Needless to say, even the configuration in which the series circuit 12a causing the internal short circuit is simply opened (claim 8) is sufficiently superior to the prior art.

  Here, the charging voltage in the constant voltage charging is 2.22 to 2.37 V per one lead storage battery cell in one series circuit (for example, in the case of FIG. 3, assuming that the lead storage battery is in the form of FIG. 53.28 to 56.88 V) is preferable. For this reason, although it is a region that is relatively close to fully charging a lead-acid battery, it does not reach the region where the water of the electrolyte (dilute sulfuric acid) is electrolyzed (the current required for electrolysis of water is balanced) (It is not added to the current).

  According to the present invention, a short circuit of a lead storage battery can be detected accurately in a short time. Therefore, it is possible to manufacture and provide a high-quality lead-acid battery, or to provide a safe power supply system incorporating this method. Therefore, it can be said that it is extremely useful in addition to high industrial applicability.

DESCRIPTION OF SYMBOLS 1 Electrode plate group 1a Positive electrode plate 1b Negative electrode plate 1c Separator 2 Battery case 2a Middle partition plate 3 Strap 4 Connection component 5 Lid 5a Liquid stopper 6 Terminal 11 Power supply system 12a, 12b, 12c Series circuit 13 Power supply part 14a, 14b, 14c Current measurement unit 15 Judgment unit 16 Notification unit 17 Switch 18a, 18b, 18c Switch 19 Load

Claims (9)

A method for detecting an internal short circuit in a lead storage battery in which an electrode plate group including a positive electrode plate, a negative electrode plate, and a separator is housed in a battery case including a plurality of cell chambers together with an electrolyte solution,
Compare the measured value of the equilibrium current in constant voltage charging of the target lead-acid battery with the threshold value based on the balanced current of the lead-acid battery that has not caused an internal short circuit, and if the measured value is greater than the threshold value, the target lead A method of detecting an internal short circuit in a lead storage battery, wherein the storage battery is determined to have an internal short circuit. The method for detecting an internal short circuit in a lead storage battery according to claim 1, wherein the charging voltage in the constant voltage charging is set to 2.22 to 2.37 V per lead storage battery cell. A power storage unit having at least one series circuit composed of one or more lead-acid batteries;
A power supply unit for charging the power storage unit at a constant voltage;
A current measuring unit individually connected to each series circuit;
When there is a series circuit that compares the measured value of the balanced current measured by the current measurement unit with the threshold value based on the balanced current of a lead-acid battery that has not caused an internal short circuit, and the measured value is greater than the threshold value A determination unit for determining that there is a lead storage battery causing an internal short circuit in the series circuit;
When there is a series circuit having a lead storage battery causing an internal short-circuit, a notification unit that identifies and notifies this series circuit according to the instruction of the determination unit;
A power supply system characterized by comprising: 4. The power supply system according to claim 3, wherein the charging voltage in constant voltage charging is set to 2.22 to 2.37 V per lead acid battery cell in one series circuit. The determination unit according to claim 3, wherein when there is a series circuit having a lead storage battery causing an internal short circuit, the determination unit has a function of instructing the power supply unit to open the series circuit. Power system. The power supply system according to claim 5, wherein the determination unit has a function of notifying a notification unit that a series circuit having a lead storage battery causing an internal short circuit is opened. When there is a series circuit with a lead-acid battery that has caused an internal short circuit, this series circuit is opened, and an internal short-circuit is caused by measuring the open circuit voltage of each lead-acid battery that constitutes the opened series circuit. The power supply system according to claim 3, wherein the determination unit has a function of specifying a lead storage battery and notifying the notification unit. A power storage unit having at least one series circuit composed of one or more lead-acid batteries;
A power supply unit for charging the power storage unit at a constant voltage;
A current measuring unit individually connected to each series circuit;
When there is a series circuit that compares the measured value of the balanced current measured by the current measurement unit with the threshold value based on the balanced current of a lead-acid battery that has not caused an internal short circuit, and the measured value is greater than the threshold value , Determining that there is a lead storage battery causing an internal short circuit in this series circuit, a determination unit that commands the power supply unit to open this series circuit,
A power supply system characterized by comprising: The power supply system according to claim 8, wherein a charging voltage in constant voltage charging is set to 2.22 to 2.37 V per lead acid battery cell in one series circuit.

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