JP6485595B2 - Battery pack - Google Patents

Description

  The present invention relates to a battery pack.

  As an existing battery pack, a plurality of battery modules connected in parallel to each other are provided, and when one battery module of the plurality of battery modules becomes abnormal, the abnormal battery module is electrically connected to other battery modules. In some cases, the power supply to the load is continued using only other battery modules.

  In the battery pack configured as described above, when the voltage difference between the battery modules increases, the reflux current flowing between the battery modules also increases as the voltage difference increases. Therefore, when a battery module that has become abnormal returns to normal and the battery module that has returned to normal is reconnected to another battery module, it supports the voltage difference between the battery module that has returned to normal and the other battery module. If the reflux current to be generated is larger than the rated current of each component such as a battery, a switch, and an electric wire constituting the battery module, the components may be deteriorated or break down due to the reflux current.

  Therefore, in order to suppress the return current corresponding to the voltage difference between the battery module that has returned to normal and the other battery module, the voltage of the battery that the battery module has returned to normal and the voltage of the battery that the other battery module has. It can be considered that the battery modules that have returned to normal are reconnected to other battery modules when the voltages become substantially the same.

  For example, when reconnecting a battery module that has returned to normal to another battery module, and when the voltage of the battery that the battery module that has returned to normal is greater than the voltage of the battery that the other battery module has, By charging the battery of the battery module, the voltage of the battery of the other battery module is raised, and the voltage of the battery of the battery module that has returned to normal is substantially the same as the voltage of the battery of the other battery module. It is possible to make it a voltage.

  Also, for example, when a battery module that has returned to normal is reconnected to another battery module, and when the voltage of the battery that the battery module that has returned to normal is lower than the voltage of the battery that the other battery module has The battery voltage of the other battery module is lowered by discharging the battery of the other battery module to reduce the voltage of the battery of the other battery module, and the battery voltage of the other battery module and the voltage of the battery of the other battery module are returned. It is conceivable that the voltages are substantially the same.

  As a related technique, there is, for example, Patent Document 1.

JP 2008-220104 A

  However, when the battery module that has returned to normal is reconnected to another battery module, and the battery voltage of the battery module that has returned to normal is smaller than the voltage of the battery that the other battery module has, the battery pack When the battery is being charged, the battery of the other battery module cannot be discharged, so the battery voltage of the battery module that has returned to normal and the voltage of the battery of the other battery module are set to substantially the same voltage. The battery module that has returned to normal while suppressing the reflux current cannot be reconnected to another battery module.

  Accordingly, an object according to one aspect of the present invention is to increase the chances of reconnecting a battery module that has returned to normal while suppressing a reflux current in a battery pack including a plurality of battery modules connected in parallel to each other. It is to plan.

  A battery pack according to one embodiment of the present invention includes a plurality of battery modules and a control unit.

  Each of the plurality of battery modules has a battery and a switch connected in series, and is connected in parallel to each other.

  The control unit disconnects the abnormal battery module from the other battery modules by turning off a switch of the abnormal battery module among the plurality of battery modules.

  In addition, the control unit returns the battery module that has returned to normal to the normal state, reconnects the battery module that has returned to normal to another battery module, and the battery voltage of the battery module that has returned to normal is When the voltage of the battery included in the other battery module is smaller than the voltage of the battery included in the other battery module, the voltage of the battery included in the other battery module becomes a predetermined voltage by charging the battery included in the other battery module. The battery voltage of the battery module that has returned to normal and the other battery modules are charged by turning on the switch of the battery module that has returned to normal and then charging the battery that the battery module that has returned to normal returns. After the voltage difference from the battery voltage of the The pitch by turning on to connect the battery module and another battery module has returned to normal.

  According to the present invention, in a battery pack including a plurality of battery modules connected in parallel to each other, it is possible to increase the chances of reconnecting a battery module that has returned to normal while suppressing the reflux current to another battery module.

It is a figure which shows an example of the battery pack of embodiment. It is a figure for demonstrating constant current constant voltage charge control. It is a flowchart which shows an example of operation | movement of a control part. It is a flowchart which shows the other example of operation | movement of a control part. It is a flowchart which shows the modification of operation | movement of the control part shown in FIG. It is a flowchart which shows the modification of operation | movement of the control part shown in FIG. It is a flowchart which shows the modification of operation | movement of the control part shown in FIG. It is a flowchart which shows the modification of operation | movement of the control part shown in FIG.

  Hereinafter, embodiments will be described in detail with reference to the drawings.

  Drawing 1 is a figure showing an example of a battery pack of an embodiment.

  A battery pack 1 shown in FIG. 1 includes a plurality of battery modules 2 connected in parallel to each other and a control unit 3. In addition, the control part 3 is comprised by CPU (Central Processing Unit) and a programmable device, for example. The battery pack 1 is mounted on a vehicle such as an electric forklift or a hybrid car, for example, and supplies power to the load Lo when a load Lo such as an inverter that drives a traveling motor is connected. The battery pack 1 is supplied with power from the load Lo or the charger Ch when the load Lo or the charger Ch is connected.

  Each battery module 2 includes a battery B, a switch SW, a current detection unit 21, a temperature detection unit 22, and a monitoring unit 23, respectively.

  Battery B is composed of a plurality of batteries (for example, a lithium ion battery, a nickel metal hydride battery, or an electric double layer capacitor) connected in series. Note that the battery B may be configured by one battery.

  The switch SW is configured by, for example, a semiconductor relay such as a MOSFET (Metal Oxide Semiconductor Field Effect Transistor) or an electromagnetic relay, and is connected to the battery B in series. When the switch SW is turned on, the battery module 2 having the switch SW is electrically connected to another battery module 2 in which the switch SW is turned on. When regenerative power is supplied from the load Lo to the battery pack 1 or when power is supplied from the charger Ch to the battery pack 1, the battery B of the battery module 2 with the switch SW turned on is charged. As a result, the voltage of the battery B rises. When the switch SW is turned off, the battery module 2 having the switch SW is electrically disconnected from other battery modules 2 in which the switch SW is turned on. In the example shown in FIG. 1, the switch SW is connected to the negative terminal side of the battery B, but the switch SW may be connected to the positive terminal side of the battery B.

  The current detection unit 21 is configured by, for example, a Hall element or a shunt resistor, and detects a current flowing through the battery B or the switch SW.

  The temperature detection unit 22 is configured by a thermistor, for example, and detects the ambient temperature of the battery B.

  The monitoring unit 23 is configured by, for example, a CPU or a programmable device, and detects the voltage of the battery B. In addition, the monitoring unit 23 controls on / off of the switch SW according to an instruction sent from the control unit 3. In addition, the monitoring unit 23 sends battery state information indicating the voltage of the battery B, the current detected by the current detection unit 21, and the temperature detected by the temperature detection unit 22 to the control unit 3.

  When at least one of the voltage, current, and temperature indicated in the battery state information is equal to or greater than the threshold, the control unit 3 determines that the battery module 2 that is the source of the battery state information is abnormal. In addition, when the voltage, current, and temperature indicated in the battery state information are all smaller than the threshold value, the control unit 3 determines that the battery module 2 that is the source of the battery state information is normal. The control unit 3 electrically disconnects the battery module 2 from the other battery modules 2 by turning off the switch SW of the battery module 2 that has become abnormal.

  Moreover, the control part 3 charges the battery B by performing constant current constant voltage charge control. That is, as shown in FIG. 2A and FIG. 2B, the control unit 3 includes the current detection unit 21 from the start of charging until the voltage V detected by the monitoring unit 23 rises to the predetermined voltage Vf. The battery B is charged by performing constant current charging control that sends a current command value to the charger Ch so that the current I detected by the monitoring unit 23 is maintained at a predetermined current, and the voltage V detected by the monitoring unit 23 is predetermined. The voltage V detected by the monitoring unit 23 is a predetermined voltage until the current I detected by the current detection unit 21 decreases to the end current If corresponding to the target charge amount of the battery B after rising to the voltage Vf. The battery B is charged by performing constant voltage charging control for sending a current command value to the charger Ch so as to be kept at Vf. Note that the predetermined voltage Vf and the end current If may be widened in consideration of variations in the full charge capacity of the battery B and the like.

  In addition, the control unit 3 returns the normal battery module 2 to the normal state, reconnects the normal battery module 2 to another battery module 2, and the normal battery module 2 returns to the normal state. When the voltage Vr of the battery B is larger than the voltage Vo of the battery B of the other battery module 2, the voltage Vo of the battery B of the other battery module 2 is charged by charging the battery B of the other battery module 2. After the voltage Vr of the battery B of the battery module 2 that has returned to normal is turned on, the switch SW of the battery module 2 that has returned to normal is turned on, and the battery module 2 that has returned to normal and the other battery module 2 Connect. The voltage Vo is an average voltage of the voltages of the batteries B included in the battery modules 2 when there are a plurality of other battery modules 2.

  In addition, the control unit 3 returns the normal battery module 2 to the normal state, reconnects the normal battery module 2 to another battery module 2, and the normal battery module 2 returns to the normal state. When the voltage Vr of the battery B is smaller than the voltage Vo of the battery B included in the other battery module 2, the voltage Vo of the battery B included in the other battery module 2 is charged by charging the battery B included in the other battery module 2. , The switch SW of the other battery module 2 is turned off, the switch SW of the battery module 2 that has returned to normal is turned on, and then the battery that the battery module 2 that has returned to normal has. After the voltage Vr of the battery B of the battery module 2 that has returned to normal by charging B reaches the predetermined voltage Vf, another battery module 2 Yuru 2 to connect the battery module 2 and the other battery module 2 back to normal by turning on the switch SW with.

  In addition, the control unit 3 returns the normal battery module 2 to the normal state, reconnects the normal battery module 2 to another battery module 2, and the normal battery module 2 returns to the normal state. When the voltage Vr of the battery B that the battery module 2 has is the same as the voltage Vo of the battery B that the other battery module 2 has, after the switch SW of the battery module 2 that has returned to normal is turned on, The battery B included and the battery B included in the other battery module 2 are charged.

  FIG. 3 is a flowchart illustrating an example of the operation of the control unit 3. It is assumed that the switches SW included in all the battery modules 2 are turned on. Moreover, the voltage of the battery B which all the battery modules 2 have shall be lower than the predetermined voltage Vf.

  First, when it is determined that all the battery modules 2 are normal (S301: No), the control unit 3 maintains the current state, and at least one battery module 2 among all the battery modules 2 is If it is determined that an abnormality has occurred (S301: Yes), the battery module 2 that has become abnormal by turning off the switch SW of the battery module 2 that has become abnormal is electrically disconnected from the other battery modules 2 (S302). .

  Next, when the controller 3 determines that the abnormal battery module 2 has not yet returned to normal (S303: No), the current state is maintained, and the abnormal battery module 2 is When it is determined that the battery module 2 has returned to normal (S303: Yes) and the voltage Vr of the battery B included in the battery module 2 returned to normal is determined to be greater than the voltage Vo of the battery B included in the other battery modules 2 (S304: Yes). The voltage Vo is increased by charging the battery B of the other battery module 2 by performing constant current charging control. At this time, the switch SW of the battery module 2 that has returned to normal is off, and the battery B of the battery module 2 that has returned to normal is not charged by the constant current charge control, so the voltage Vr does not increase.

  Next, when it is determined that the voltage Vo has not increased to the voltage Vr (S306: No), the control unit 3 maintains the current state and determines that the voltage Vo has increased to the voltage Vr (S306). : Yes), the switch SW of the battery module 2 that has returned to normal is turned on to connect the battery module 2 that has returned to normal and the other battery module 2 (S307). At this time, since the voltage Vr and the voltage Vo are substantially the same, the battery module 2 that has returned to normal while suppressing the reflux current can be reconnected to another battery module 2. In S307, when the switch SW of the battery module 2 that has returned to normal is turned on and the battery module 2 that has returned to normal and the other battery module 2 are connected, the battery B of the battery module 2 that has returned to normal and Since the battery B included in the other battery module 2 is charged by the constant current charging control, the voltages Vr and Vo increase.

  Next, when the control unit 3 determines that the voltages Vr and Vo have not increased to the predetermined voltage Vf (S308: No), the current state is maintained, and the voltages Vr and Vo increase to the predetermined voltage Vf. If it is determined that the battery module 2 has returned to normal by performing constant voltage charge control, the battery B of the battery module 2 and the battery B of the other battery module 2 are charged. (S309). The predetermined voltage Vf is the same as the constant voltage in the constant voltage charge control, but it does not have to be exactly the same.

  Further, when the control unit 3 determines that the battery module 2 that has become abnormal has returned to normal (S303: Yes) and determines that the voltage Vr is smaller than the voltage Vo (S304: No, S310: Yes), the constant current By performing the charge control, the voltage Vo is increased by charging the battery B of the other battery module 2 (S311). At this time, the switch SW of the battery module 2 that has returned to normal is off, and the battery B of the battery module 2 that has returned to normal is not charged by the constant current charge control, so the voltage Vr does not increase.

  Next, when it is determined that the voltage Vo has not increased to the predetermined voltage Vf (S312: No), the control unit 3 maintains the current state and determines that the voltage Vo has increased to the predetermined voltage Vf. (S312: Yes), the switch SW of the other battery module 2 is turned off, and the switch SW of the battery module 2 returned to normal is turned on (S313). Then, the battery B included in the battery module 2 that has returned to normal by the constant current charge control is charged, and the voltage Vr increases. At this time, the switch SW included in the other battery module 2 is off, and the battery B included in the other battery module 2 is not charged, so the voltage Vo does not increase.

  Next, when it is determined that the voltage Vr has not increased to the predetermined voltage Vf (S314: No), the control unit 3 maintains the current state and determines that the voltage Vr has increased to the predetermined voltage Vf. (S314: Yes), the constant current charging control is terminated, and the switch SW included in the other battery module 2 is turned on to connect the battery module 2 that has returned to normal and the other battery module 2 (S315). At this time, since the voltage Vr is the predetermined voltage Vf, the voltage Vo is the predetermined voltage Vf, and the voltage Vr and the voltage Vo are substantially the same, the battery module 2 that has returned to normal while suppressing the return current is replaced with another battery. The module 2 can be reconnected.

  Next, the control unit 3 reconnects the battery module 2 that has returned to normal in S315 to the other battery module 2, and then performs the constant voltage charging control so that the battery B included in the battery module 2 that has returned to normal and The battery B included in the other battery module 2 is charged (S309).

  The control unit 3 determines that the battery module 2 that has become abnormal has returned to normal (S303: Yes), and determines that the voltage Vr is the same as the voltage Vo (S304: No, S310: No). The switch SW of the battery module 2 that has returned to is turned on (S316). At this time, since the voltage Vr and the voltage Vo are substantially the same, the battery module 2 that has returned to normal while suppressing the reflux current can be reconnected to another battery module 2.

  And the control part 3 charges the battery B which the battery module 2 which returned to normal by performing constant current constant voltage charge control, and the battery B which the other battery module 2 has (S317).

  FIG. 4 is a flowchart illustrating another example of the operation of the control unit 3. It is assumed that the switches SW included in all the battery modules 2 are turned on. Moreover, the voltage of the battery B which all the battery modules 2 have shall be lower than the predetermined voltage Vf. Further, S401 to 409 shown in FIG. 4 are the same as S301 to S309 shown in FIG.

  The control unit 3 determines that the battery module 2 that has become abnormal has returned to normal (S403: Yes), and the voltage Vr of the battery B of the battery module 2 that has returned to normal is that of the battery B of the other battery module 2. If it is determined that the voltage is smaller than the voltage Vo (S404: No, S410: Yes), the voltage Vo is reduced to the predetermined voltage Vf by charging the battery B included in the other battery module 2 by performing constant current constant voltage charging control. After the increase, the current Io flowing through the battery B of the other battery module 2 is decreased (S411). At this time, the switch SW of the battery module 2 that has returned to normal is off, and the battery B of the battery module 2 that has returned to normal is not charged by the constant-current / constant-voltage charge control, so the voltage Vr does not increase.

  Next, when it is determined that the current Io has not decreased to the end current If (S412: No), the control unit 3 maintains the current state and determines that the current Io has decreased to the end current If. (S412: Yes), the switch SW of the other battery module 2 is turned off, and the switch SW of the battery module 2 returned to normal is turned on (S413).

  Next, the control unit 3 increases the voltage Ir to the predetermined voltage Vf by charging the battery B included in the battery module 2 that has returned to normal by performing constant current / constant voltage charging control, and then the current Ir. Decrease (S414). At this time, the switch SW included in the other battery module 2 is off, and the battery B included in the other battery module 2 is not charged by the constant current / constant voltage charging control, so the voltage Vo does not increase.

  Next, when it is determined that the current Ir has not decreased to the end current If (S415: No), the control unit 3 maintains the current state and determines that the current Ir has decreased to the end current If. (S415: Yes) By turning on the switch SW of the other battery module 2, the battery module 2 that has returned to normal and the other battery module 2 are connected (S416). At this time, since the voltage Vr is the predetermined voltage Vf, the voltage Vo is the predetermined voltage Vf, and the voltage Vr and the voltage Vo are substantially the same, the battery module 2 that has returned to normal while suppressing the return current is replaced with another battery. The module 2 can be reconnected.

  The control unit 3 determines that the battery module 2 that has become abnormal has returned to normal (S403: Yes), and determines that the voltage Vr is the same as the voltage Vo (S404: No, S410: No). The switch SW of the battery module 2 that has returned to is turned on (S417). At this time, since the voltage Vr and the voltage Vo are substantially the same, the battery module 2 that has returned to normal while suppressing the reflux current can be reconnected to another battery module 2.

  And the control part 3 charges the battery B which the battery module 2 which returned to normal by performing constant current constant voltage charge control, and the battery B which the other battery module 2 has (S418).

  That is, the control unit 3 that performs the operation shown in FIG. 3 is configured to reconnect the battery module 2 that has returned to normal to the other battery module 2, and the voltage Vr of the battery B included in the battery module 2 that has returned to normal. Is lower than the voltage Vo of the battery B of the other battery module 2, when charging the battery B of the other battery module 2, the battery module 2 has returned to normal by performing constant current charge control. When charging B, constant current charging control is performed, and after the battery module 2 that has returned to normal is reconnected to another battery module 2, the battery B and the other battery module 2 that the battery module 2 that has returned to normal returns When charging the battery B included in the battery, constant voltage charging control is performed.

  Further, the control unit 3 that performs the operation shown in FIG. 4 is configured to reconnect the battery module 2 that has returned to normal to the other battery module 2, and the voltage Vr of the battery B included in the battery module 2 that has returned to normal. Is smaller than the voltage Vo of the battery B included in the other battery module 2, when charging the battery B included in the other battery module 2, the battery module 2 that has returned to normal is controlled by performing constant current / constant voltage charging control. When the battery B is charged, constant current constant voltage charge control is performed.

  Thus, in the battery pack 1 of the embodiment, when the battery module 2 that has returned to normal is reconnected to the other battery module 2 and when the voltage Vr is smaller than the voltage Vo, the other battery module 2 The voltage Vo is set to the predetermined voltage Vf by charging the battery B, and then the voltage Vr is set to the predetermined voltage Vf by charging the battery B included in the battery module 2 that has returned to normal. As a result, when the battery module 2 that has returned to normal is reconnected to another battery module 2 and the voltage Vr is smaller than the voltage Vo, the voltages Vr and Vo can be obtained even when the battery pack 1 is being charged. Can be set to the predetermined voltage Vf, and the voltage Vr and the voltage Vo can be set to substantially the same voltage. Therefore, the battery module 2 that has returned to normal can be reconnected to another battery module 2 while suppressing the reflux current. . That is, according to the battery pack 1 of the embodiment, it is possible to increase the chances of reconnecting the battery module 2 that has returned to normal while suppressing the reflux current to another battery module 2.

  By the way, unlike the battery pack 1 of the embodiment, when the battery module 2 that has returned to normal is reconnected to another battery module 2 and when the voltage Vr is smaller than the voltage Vo, the battery module 2 that has returned to normal. It is also conceivable to increase the voltage Vo to the predetermined voltage Vf by charging the battery B included in another battery module 2 after the voltage Vr is increased to the predetermined voltage Vf by charging the battery B included in the In the case of such a configuration, and when the number of battery modules 2 that have returned to normal is smaller than the number of other battery modules 2, if the charging of the battery pack 1 is terminated halfway, the entire battery pack 1 is charged. Since the charging of the battery pack 1 is completed without increasing the amount of charge, the increase in the charging amount of the battery pack 1 is not accompanied by the charging time. The there is a possibility that the user will remember.

  On the other hand, in the battery pack 1 of the embodiment, when the battery module 2 that has returned to normal is reconnected to the other battery module 2 and when the voltage Vr is smaller than the voltage Vo, the battery that the other battery module 2 has After charging the voltage Vo to the predetermined voltage Vf by charging B, the voltage Vr is set to the predetermined voltage Vf by charging the battery B included in the battery module 2 that has returned to normal. When the number of the battery packs 2 is smaller than the number of the other battery modules 2, the charge amount of the battery pack 1 can be increased sufficiently even if the charge of the battery pack 1 is terminated halfway. It is possible to prevent the user from feeling a sense of discomfort, such as the amount of increase not accompanying the charging time.

  Further, the present invention is not limited to the above-described embodiment, and various improvements and changes can be made without departing from the gist of the present invention.

  5 and 6 are flowcharts showing a modification of the operation of the control unit 3 shown in FIG. It is assumed that the switches SW included in all the battery modules 2 are turned on. Moreover, the voltage of the battery B which all the battery modules 2 have shall be lower than the predetermined voltage Vf. Further, S501 to 509 shown in FIG. 5 are the same as S301 to S309 shown in FIG. Further, S517 to S518 shown in FIG. 5 are the same as S316 to S317 shown in FIG.

  As shown in FIG. 5, the control unit 3 determines that the battery module 2 that has become abnormal has returned to normal (S503: Yes), and the voltage Vr of the battery B included in the battery module 2 that has returned to normal is the other battery. When it is determined that the voltage is lower than the voltage Vo of the battery B included in the module 2 (S504: No, S510: Yes), it is determined whether or not the voltage Vr is equal to or lower than the threshold value Vth (S511). Note that the threshold value Vth is, for example, the voltage of the battery B immediately before overdischarge.

  Next, when the control unit 3 determines that the voltage Vr is greater than the threshold value Vth (S511: No), the process proceeds to S512. Since the processing after S512 is the same as the processing after S311 in FIG. 3, the description thereof is omitted.

  Next, when the control unit 3 determines that the voltage Vr is equal to or lower than the threshold value Vth (S511: Yes), as shown in FIG. 6, the switch SW included in the other battery module 2 is turned off and returned to normal. The switch SW included in the battery module 2 is turned on (S519), and the voltage Vr is increased by charging the battery B included in the battery module 2 that has returned to normal by performing constant current charge control (S520). At this time, the switch SW included in the other battery module 2 is turned off, and the battery B included in the other battery module 2 is not charged by the constant current charging control. Therefore, the voltage Vo does not increase.

  Next, when the control unit 3 determines that the voltage Vr is not the same or substantially the same as the voltage Vo (S521: No), the current state is maintained, and the voltage Vr is the same or substantially the same as the voltage Vo. If it is determined that they are the same (S521: Yes), the switch SW of the other battery module 2 is turned on to connect the battery module 2 that has returned to normal and the other battery module 2 (S522). At this time, since the voltage Vr and the voltage Vo are the same or substantially the same, the battery module 2 that has returned to normal while suppressing the return current can be reconnected to another battery module 2.

  Next, as shown in FIG. 5, the control unit 3 charges the battery B of the battery module 2 that has returned to normal by performing constant voltage charging control and the battery B of the other battery module 2 (S509). .

  That is, the control unit 3 that performs the operations shown in FIGS. 5 and 6 returns the normal battery module 2 to the normal state, and reconnects the normal battery module 2 to the other battery module 2. In addition, when the voltage Vr of the battery B included in the battery module 2 that has returned to normal is smaller than the voltage Vo of the battery B included in the other battery module 2, and when the voltage Vr is equal to or less than the threshold value Vth, another battery Battery module 2 returned to normal by turning off switch SW included in module 2 and turning on switch SW included in battery module 2 returned to normal to charge battery B included in battery module 2 returned to normal When the voltage Vr of the battery B of the other battery module 2 is the same or substantially the same as the voltage Vo of the battery B of the other battery module 2, the other battery module 2 To connect the battery module 2 and the other battery module 2 back to normal by turning on the switch SW with.

  Thereby, when the voltage Vr of the battery B included in the battery module 2 returned to normal is equal to or lower than the threshold Vth, the battery B included in the battery module 2 returned to normal earlier than the battery B included in the other battery module 2 is present. Since the battery B of the battery module 2 that has returned to normal is in an over-discharged state, the battery B 1 that has been over-discharged remains uncharged even if the charging of the battery pack 1 is terminated halfway. It can suppress that it is left and it becomes an overdischarge.

  In S313 of FIG. 3, when the switch SW of the battery module 2 that has returned to normal is turned on, the battery B of the battery module 2 that has returned to normal by the constant current charge control is charged, and the voltage Vr increases. 3, when the switch SW of the other battery module 2 is turned off, a voltage component that is an integrated value of the current flowing through the battery B of the other battery module 2 and the internal resistance of the battery B is obtained. The voltage Vo drops below the predetermined voltage Vf. In addition, after the switch SW included in the other battery module 2 is turned off, the polarization of the battery B included in the other battery module 2 is eliminated, and thus the voltage Vo gradually decreases. Therefore, in S314 of FIG. 3, when the voltage Vr rises to the predetermined voltage Vf, a voltage difference is generated between the voltage Vr and the voltage Vo.

  From this, as shown in FIG. 3, when it is determined that “the voltage Vr has increased to the predetermined voltage Vf (S314: Yes), the battery returned to normal by turning on the switch SW of the other battery module 2 is turned on. As shown in FIG. 7, the operation of the control unit 3 to connect the module 2 and another battery module 2 (S315) is as follows: “The voltage difference ΔV between the voltage Vr and the voltage Vo is equal to or less than a predetermined value ΔVth”. If it judges (S314 ': Yes), the battery module 2 and the other battery module 2 which returned to normal will be connected by turning on switch SW which the other battery module 2 has (S315). It can be replaced with an action.

  That is, the control unit 3 that performs the operation shown in FIG. 7 returns the normal battery module 2 to the normal state and reconnects the normal battery module 2 to the other battery module 2 and is normal. When the voltage Vr of the battery B included in the battery module 2 that has returned to is smaller than the voltage Vo of the battery B included in the other battery module 2, the other battery module 2 is charged by charging the battery B included in the other battery module 2. After the voltage Vo of the battery B included in the battery module reaches the predetermined voltage Vf, the switch SW included in the other battery module 2 is turned off, the switch SW included in the battery module 2 returned to normal is turned on, and then returned to normal. When the battery B included in the battery module 2 is charged, the voltage Vr of the battery B included in the battery module 2 returned to normal and other battery modules After the voltage difference ΔV with the voltage Vo of the battery 2 becomes equal to or less than the predetermined value ΔVth, the switch SW of the other battery module 2 is turned on to connect the battery module 2 and the other battery module 2 that have returned to normal. .

  When S314 shown in FIG. 3 is replaced with S314 ′ shown in FIG. 7, the control unit 3 does not end the constant current charging control when the switch SW of the other battery module 2 is turned on (S315). . In addition, when replacing S314 shown in FIG. 3 with S314 ′ shown in FIG. 7, the controller 3 turns on the switch SW of the other battery module 2 (S315), and then the operation of S308 instead of the operation of S309. Shall be transferred to.

  That is, when the control unit 3 that performs the operation shown in FIG. 7 charges the battery B included in the other battery module 2, the control unit 3 performs constant current charging control and charges the battery B included in the battery module 2 that has returned to normal. After performing the constant current charging control and reconnecting the battery module 2 that has returned to normal to the other battery module 2, the battery B that the battery module 2 that has returned to normal and the battery B that the other battery module 2 has have When charging, constant voltage charge control is performed after performing constant current charge control.

  The predetermined value ΔVth may be zero, or may be a value other than zero in consideration of variations in voltage detection accuracy of the monitoring unit 23. By setting the predetermined value ΔVth to zero or substantially zero, when the battery module 2 that has returned to normal is reconnected to another battery module 2, the voltage Vr and the voltage Vo can be the same or substantially the same. , The reflux current can be suppressed.

  Similarly, when it is determined that “the voltage Vr has increased to the predetermined voltage Vf” (S515: Yes), the battery module 2 that has returned to normal is turned on by turning on the switch SW of the other battery module 2. When the operation of the control unit 3 “connects the battery module 2 to another battery module 2 (S516)” is determined as “the voltage difference ΔV between the voltage Vr and the voltage Vo is equal to or less than a predetermined value ΔVth, as shown in FIG. (S515 ′: Yes), by turning on the switch SW of the other battery module 2, the battery module 2 returned to normal and the other battery module 2 are connected (S516) ”. It is also possible to replace it.

  When S515 shown in FIG. 5 is replaced with S515 ′ shown in FIG. 8, the control unit 3 does not end the constant current charge control when turning on the switch SW of the other battery module 2 (S516). . Further, when replacing S515 shown in FIG. 5 with S515 ′ shown in FIG. 8, the control unit 3 turns on the switch SW of the other battery module 2 (S516), and then the operation of S508 instead of the operation of S509. Shall be transferred to. In FIG. 8, when the control unit 3 determines that the voltage Vr is equal to or lower than the threshold value Vth (S511: Yes), the control unit 3 proceeds to S519 shown in FIG.

  That is, the control unit 3 that performs the operation shown in FIG. 8 returns the normal battery module 2 to a normal state and reconnects the normal battery module 2 to another battery module 2 and is normal. When the voltage Vr of the battery B included in the battery module 2 that has returned to is smaller than the voltage Vo of the battery B included in the other battery module 2, the voltage Vr of the battery B included in the battery module 2 that has returned to normal is the threshold value. When the voltage B is larger than Vth, the battery B of the other battery module 2 is charged to charge the voltage Vo of the battery B of the other battery module 2 to the predetermined voltage Vf, and then the switch SW of the other battery module 2 has. The switch SW of the battery module 2 that has returned to normal is turned on, and then the battery that the battery module 2 that has returned to normal returns After the voltage difference ΔV between the voltage Vr of the battery B included in the battery module 2 that has returned to normal by charging and the voltage Vo of the battery B included in the other battery module 2 becomes equal to or less than the predetermined value ΔVth, another battery The battery module 2 that has returned to normal by turning on the switch SW of the module 2 is connected to the other battery module 2.

DESCRIPTION OF SYMBOLS 1 Battery pack 2 Battery module 3 Control part 21 Current detection part 22 Temperature detection part 23 Monitoring part Lo Load Ch Battery charger B Battery SW switch

Claims (6)

A plurality of battery modules each having a battery and a switch connected in series, and connected in parallel to each other;
Of the plurality of battery modules, by turning off the switch of the battery module that has become abnormal, a control unit that disconnects the battery module that has become abnormal from other battery modules,
With
The control unit returns the battery module that has returned to normal to a normal state, reconnects the battery module that has returned to normal to the other battery module, and the battery module that the battery module that has returned to normal returns. When the voltage is lower than the voltage of the battery included in the other battery module, the battery voltage included in the other battery module is changed to the predetermined voltage by charging the battery included in the other battery module. The battery module returned to normal is turned off by turning off the switch of the battery module and turning on the switch of the battery module returned to normal, and then charging the battery of the battery module returned to normal. The voltage difference between the voltage of the battery having and the voltage of the battery of the other battery module is a predetermined value or less After becoming the battery pack, characterized in that to connect the other battery modules returned to the normal by turning on a switch included in the battery module and the other battery modules. The battery pack according to claim 1,
The control unit performs constant current charge control when charging a battery included in the other battery module, and performs constant current charge control when charging a battery included in the battery module that has returned to normal. After recharging the returned battery module to the other battery module, when charging the battery included in the battery module returned to normal and the battery included in the other battery module, the constant current charge control is performed and then the battery module is charged. A battery pack characterized by performing voltage charging control. The battery pack according to claim 1,
The control unit returns the battery module that has returned to normal to a normal state, reconnects the battery module that has returned to normal to the other battery module, and the battery module that the battery module that has returned to normal returns. When the voltage is lower than the voltage of the battery included in the other battery module, the battery voltage included in the other battery module is changed to the predetermined voltage by charging the battery included in the other battery module. The battery module returned to normal is turned off by turning off the switch of the battery module and turning on the switch of the battery module returned to normal, and then charging the battery of the battery module returned to normal. The switch that the other battery module has after the voltage of the battery it has becomes the predetermined voltage Battery pack, characterized in that to connect the turned on so the battery modules returned to the normally and the other battery modules. The battery pack according to claim 3,
The control unit performs constant current charge control when charging a battery included in the other battery module, and performs constant current charge control when charging a battery included in the battery module that has returned to normal. After reconnecting the returned battery module to the other battery module, when charging the battery included in the battery module returned to normal and the battery included in the other battery module, constant voltage charging control is performed. Battery pack. The battery pack according to claim 3,
The control unit performs constant current / constant voltage charging control when charging a battery included in the other battery module, and performs constant current / constant voltage charging control when charging a battery included in the battery module that has returned to normal. A battery pack characterized by that. The battery pack according to claim 1 or 3, wherein
The control unit returns the battery module that has returned to normal to a normal state, reconnects the battery module that has returned to normal to the other battery module, and the battery module that the battery module that has returned to normal returns. When the voltage is lower than the voltage of the battery included in the other battery module and the voltage of the battery included in the battery module returned to normal is equal to or lower than the threshold, the switch included in the other battery module is turned off. In addition, by turning on the switch of the battery module that has returned to normal and charging the battery of the battery module that has returned to normal, the voltage of the battery that the battery module that has returned to normal returns to the other battery When the voltage of the battery of the module is the same or substantially the same, the switch of the other battery module Battery pack, characterized in that to connect the turned on so the battery modules returned to the normally and the other battery modules.

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