JP7691660B2 - battery power supply - Google Patents

Description

The present invention relates to a battery power supply device that uses a battery as a power source.

Conventionally, various electric devices that can have detachable battery packs are known, such as electric bicycles, electric tools, electric carry carts, electric suitcases, electric wheelbarrows, electric lawnmowers, electric tillers, and electric kick scooters (see, for example, Patent Document 1).

JP 2011-079510 A

However, electric devices such as electric bicycles and power tools are not used all the time. Therefore, when the electric device is not being used, the battery packs and secondary batteries such as single cells of the electric device are not being used.

The object of the present invention is to provide a battery power supply device that makes it easy to effectively utilize secondary batteries.

The battery power supply device according to the present invention comprises a series battery module in which a plurality of battery blocks are connected in series, a detachment control unit that controls the attachment and detachment of the battery block, and an operation reception unit that receives the user's designation of the battery block, and each of the battery blocks includes a first terminal that can be connected to one pole of a secondary battery, a second terminal that can be connected to the other pole of the secondary battery, a series switching element that is connected in series to the secondary battery that is connected to the first and second terminals, and a bypass switching element that is connected in parallel to an intra-block series circuit in which the secondary battery and the series switching element are connected in series, and a small number of the plurality of battery blocks include a bypass switching element that is connected in parallel to the intra-block series circuit in which the secondary battery and the series switching element are connected in series. At least one of the secondary batteries is removable, and the series battery module is configured such that the multiple battery blocks are connected in series by connecting the parallel circuit between the bypass switching element and the series circuit within the block in each battery block in series, and the removal control unit can control each battery block to an added state in which the bypass switching element is turned off and the series switching element is turned on, and a removed state in which the series switching element is turned off and the bypass switching element is turned on, and when the designation of the battery block is accepted by the operation acceptance unit, the designated battery block is placed in the removed state.

According to this configuration, when the user specifies a battery block from which the secondary battery is to be removed using the operation reception unit, the battery block is put into a detached state, the series switching element is turned off, and the bypass switching element is turned on. As a result, the current flowing through the secondary battery in the specified battery block becomes zero, and the user can remove the secondary battery from the battery block and use it effectively for another purpose. Meanwhile, because the bypass switching element is turned on, the remaining secondary batteries other than the removed secondary battery remain connected in series. As a result, it becomes possible to output a voltage that is the sum of the output voltages of the remaining secondary batteries. This makes it possible to achieve both high voltage output by the battery power supply device and effective use of the secondary batteries.

It is also preferable that the battery block further includes a ground terminal for grounding, and at least one of the battery blocks further includes a ground switching element interposed between one of the first and second terminals and the ground terminal, and the intra-block series circuit of the battery block including the ground switching element further includes a disconnection switching element connected in series to the secondary battery on the opposite side to the series switching element, and when the operation reception unit receives the designation of the battery block including the ground switching element, the detachment control unit turns off the series switching element by placing the designated battery block in the detached state, and further turns off the disconnection switching element and turns on the ground switching element.

According to this configuration, when a user specifies a battery block from which the secondary battery is to be removed using the operation reception unit, the battery block is placed in a detached state, the series switching element is turned off, the disconnect switching element is turned off, and the ground switching element is turned on. As a result, the current flowing through the specified secondary battery becomes zero, and the secondary battery is placed in an electrically floating state. In this state, the ground switching element is turned on, and the secondary battery becomes at ground potential. In this way, the current flowing through the specified secondary battery becomes zero and the secondary battery becomes at ground potential, thereby improving the safety of the user attempting to remove the secondary battery.

In addition, when the secondary battery is attached to the battery block from which the secondary battery has been removed, the attachment/detachment control unit preferably further turns off the ground switching element and turns on the disconnect switching element of the battery block to which the secondary battery is attached.

With this configuration, the attached secondary battery can be switched between a detached state and an attached state.

In addition, when the secondary battery is attached to the battery block from which the secondary battery has been removed, the attachment/detachment control unit preferably sets the battery block to which the secondary battery is attached to the added state.

With this configuration, the output voltage of the attached secondary battery is added to the output voltage of the series battery module.

It is also preferable that the battery block further includes a ground terminal for grounding, and at least one of the battery blocks further includes a contact terminal that is capable of contacting the housing of the secondary battery and is electrically connected to the ground terminal.

With this configuration, the secondary battery's housing is at ground potential, improving the safety of users attempting to insert or remove the secondary battery.

It is also preferable to further include an SOC acquisition unit that acquires the SOC of the secondary battery of each of the battery blocks, and a charging control unit that, when charging the series battery module, groups the battery blocks among the plurality of battery blocks whose secondary battery SOC is less than 100% into a first group whose secondary battery SOC is relatively high and a second group whose secondary battery SOC is relatively low, and places the battery blocks of the first group in the joining state and the battery blocks of the second group in the withdrawn state, thereby preferentially charging the battery blocks of the first group.

According to this configuration, secondary batteries with a relatively high SOC, i.e., batteries that take less time to become fully charged, are charged preferentially. As a result, each secondary battery is charged so that the number of fully charged secondary batteries increases quickly. When the number of fully charged secondary batteries increases, it becomes easier for a user to remove a fully charged secondary battery from the battery power supply device and use it when the user needs a secondary battery to use an electrically powered device. As a result, user convenience is improved.

Furthermore, it is preferable that the charging control unit selects the battery block with the highest SOC among the battery blocks whose SOC is less than 100% as the first group.

This configuration minimizes the time it takes to add another fully charged secondary battery.

It is also preferable to further include an SOC acquisition unit that acquires the SOC of the secondary battery of each battery block, and a discharge control unit that places the battery block including the secondary battery whose SOC indicates full charge in the detached state when discharging the series battery module.

With this configuration, fully charged secondary batteries are not discharged, so the number of fully charged secondary batteries is maintained as high as possible. The more fully charged secondary batteries there are, the easier it is for a user to remove a fully charged secondary battery from the battery power supply device and use it when the user needs a secondary battery to operate an electrically powered device. As a result, user convenience is improved.

It is also preferable to further include an SOC acquisition unit that acquires the SOC of the secondary batteries of each of the battery blocks, and a charging control unit that controls the charging of each of the battery blocks by controlling the switching of each of the battery blocks between the joining state and the withdrawal state so as to equalize the SOC of the secondary batteries of each of the battery blocks.

With this configuration, each secondary battery can be selectively charged by switching between a joined state and a disconnected state, making it easier to equalize the SOC of each secondary battery.

In addition, it is preferable that the charging control unit controls the charging of each battery block based on at least one of the following in addition to the SOC: the temperature of the secondary battery of each battery block; the continuous current-on time, which is the continuous time that each battery block has been in a connected state going back from the current time; and the continuous pause time, which is the continuous time that each battery block has been in a disconnected state going back from the current time.

If the temperature of a secondary battery is high, it is more likely to deteriorate. If the continuous current-flow time is long, it is more likely to deteriorate. Therefore, by controlling the charging of each battery block based on the temperature of the secondary battery or the continuous current-flow time, it is easy to reduce the deterioration of the secondary battery. In addition, by taking into account the continuous rest time, the secondary battery is periodically disconnected and the open circuit voltage can be measured, which makes it easy to accurately obtain the SOC of the secondary battery.

It is also preferable to further include an SOC acquisition unit that acquires the SOC of the secondary batteries of each of the battery blocks, and a discharge control unit that controls the discharge of each of the battery blocks by controlling the switching of each of the battery blocks between the joining state and the withdrawal state so as to equalize the SOC of the secondary batteries of each of the battery blocks.

With this configuration, each secondary battery can be selectively discharged by switching between the connected and disconnected states, making it easier to equalize the SOC of each secondary battery.

In addition, it is preferable that the discharge control unit controls the discharge of each battery block based on at least one of the following in addition to the SOC: the temperature of the secondary battery of each battery block; the continuous current-on time, which is the continuous time that each battery block has been in a connected state going back from the current time; and the continuous pause time, which is the continuous time that each battery block has been in a disconnected state going back from the current time.

If the temperature of a secondary battery is high, it is more likely to deteriorate. If the continuous current-flow time is long, it is more likely to deteriorate. Therefore, by controlling the discharge of each battery block based on the temperature of the secondary battery or the continuous current-flow time, it is easy to reduce the deterioration of the secondary battery. In addition, by taking into account the continuous rest time, the secondary battery is periodically disconnected and the open circuit voltage can be measured, which makes it easy to accurately obtain the SOC of the secondary battery.

It is also preferable that at least one of the plurality of battery blocks further includes an inversion circuit that inverts the polarity of the secondary battery.

This configuration makes it possible to connect some of the multiple battery blocks connected in series with the polarity reversed. As a result, it is possible to increase the degree of freedom in the voltage obtained from the series battery module and to easily transfer the charge amount between battery blocks in the series battery module.

It is also preferable that each of the secondary batteries is a battery pack for an electrically powered device.

With this configuration, by attaching multiple battery packs for electrically powered devices to each battery block, it is possible to obtain the series voltage of multiple battery packs, making it easier to make effective use of the battery packs.

It is also preferable that the device further includes a plurality of the secondary batteries.

According to this configuration, the battery power supply device is equipped with multiple secondary batteries.

A battery power supply device configured in this way makes it easy to make effective use of secondary batteries.

1 is a block diagram showing an example of the configuration of a battery power supply device according to a first embodiment of the present invention. 2 is a flowchart showing an example of a process of detachment control by a detachment control unit 31 shown in FIG. 1 . 2 is a flowchart showing an example of a charging control process performed by a charging control unit 33 shown in FIG. 1 . 2 is a flowchart showing an example of a discharge control process performed by a discharge control unit 34 shown in FIG. 1 . 2 is a conceptual circuit diagram showing a modified example of the series battery module 2 shown in FIG. 1 . FIG. 11 is a block diagram showing an example of the configuration of a battery power supply device 1a according to a second embodiment of the present invention. 7 is a flowchart showing an example of a charging control process performed by a charging control unit 33a shown in FIG. 6. 7 is a flowchart showing an example of a discharge control process performed by a discharge control unit 34a shown in FIG. 6. 13 is a block diagram showing an example of the configuration of a battery power supply device 1b according to a third embodiment of the present invention. FIG. 10 is a flowchart showing an example of a process of detachment control by the detachment control unit 31b shown in FIG. 9; FIG. 11 is an explanatory diagram for explaining steps S2b and S51. 10 is a conceptual circuit diagram showing a modification of series battery module 2b shown in FIG. 9.

The following describes an embodiment of the present invention with reference to the drawings. Note that components with the same reference numerals in each drawing are the same, and their description will be omitted.

(First embodiment)

Figure 1 is a block diagram showing an example of the configuration of a battery power supply device according to a first embodiment of the present invention. The battery power supply device 1 shown in Figure 1 generally comprises a series battery module 2, a control unit 3, and a touch panel display 4 (operation reception unit). The series battery module 2 comprises multiple battery blocks BB, input/output terminals TT1, TT2, and a ground terminal TE for grounding. In the example shown in Figure 1, the series battery module 2 comprises N battery blocks BB.

The multiple battery blocks BB are connected in series. Each battery block BB is assigned a block number from 1 to N, starting from the high potential side. The battery block BB with block number 1 is referred to as battery block BB1, the battery block BB with block number 2 as battery block BB2, and the battery block BB with block number N as battery block BBN.

The battery block BB includes a first terminal T1 that can be connected to the positive pole (one pole) of the secondary battery B, a second terminal T2 that can be connected to the negative pole (the other pole) of the secondary battery B, a series switching element SS that is connected in series to the secondary battery B that is connected to the first terminal T1 and the second terminal T2, a bypass switching element BS that is connected in parallel to the intra-block series circuit SC in which the secondary battery B and the series switching element SS are connected in series, and a contact terminal CT that can come into contact with the housing BH of the secondary battery B and is conductive with the ground terminal TE.

The series switching element SS and the bypass switching element BS may be semiconductor switching elements such as transistors, or may be mechanical relay switches. The series switching element SS and the bypass switching element BS are turned on and off in response to a control signal from the control unit 3.

One end of the parallel circuit of the intra-block series circuit SC and the bypass switching element BS is designated as P1 and the other end as P2. One end P1 of the battery block BB1 is connected to the input/output terminal TT1, and the other end P2 of the battery block BBN is connected to the input/output terminal TT2. Between the battery blocks BB1 to BBN, the other end P2 of the battery block BB on the high potential side is connected to one end P1 of the battery block BB on the low potential side.

As a result, the parallel circuits of the intra-block series circuits SC and the bypass switching elements BS in each battery block BB are connected in series, thereby connecting multiple battery blocks BB in series. The input/output terminals TT1 and TT2 are input/output terminals for the entire series battery module 2 and are input/output terminals for the battery power supply device 1. When the battery power supply device 1 is discharging, the series voltage of the multiple battery blocks BB is output to the input/output terminals TT1 and TT2, and when the battery power supply device 1 is charging, the charging voltage applied to the input/output terminals TT1 and TT2 is applied to the series circuit of the multiple battery blocks BB.

The first terminal T1 and the second terminal T2 are, for example, contact terminals or connectors, and can be connected to the positive and negative poles of the secondary battery B. This allows the secondary battery B to be detached from the battery block BB. Hereinafter, the secondary battery B attached to each battery block BB may be referred to by its block number, such as the secondary battery B in battery block BB1 being referred to as secondary battery B1, the secondary battery B in battery block BB2 being referred to as secondary battery B2, and the secondary battery B in battery block BBN being referred to as secondary battery BN.

Note that this is not limited to an example in which all battery blocks BB are capable of detaching the secondary battery B, and it is sufficient that at least one of the battery blocks BB1 to BBN is capable of detaching the secondary battery B. The first terminal T1 and the second terminal T2 are sufficient if they are capable of connecting the secondary battery B, and the battery blocks BB1 to BBN may include a battery block BB equipped with connection terminals for fixedly connecting the secondary battery B as the first terminal T1 and the second terminal T2.

The secondary battery B may be a battery pack of secondary batteries used in various electric devices, such as electric bicycles, electric tools, electric carry carts, electric suitcases, electric wheelbarrows, electric lawnmowers, electric tillers, and electric kickboards. The multiple secondary batteries B may also include a mixture of battery packs of different electric devices. The multiple secondary batteries B may also include single cells of secondary batteries.

The secondary battery B has a housing BH. The housing BH is the outer shell of the secondary battery B, which is insulated from the positive and negative terminals and signal terminals of the secondary battery B.

The contact terminal CT is a conductive contact member such as a leaf spring, coil spring, or electrode plate. When a secondary battery B is attached to the battery block BB, the contact terminal CT is adapted to come into contact with the housing BH. Since the contact terminal CT is conductive with the ground terminal TE, when a secondary battery B is attached to the battery block BB, the housing BH of the secondary battery B is grounded via the contact terminal CT and the ground terminal TE. As a result of the secondary battery B2 being at ground potential, the safety of a user attempting to attach or detach a secondary battery B to or from the battery block BB is improved.

Note that the present invention is not limited to an example in which all battery blocks BB have contact terminals CT, and at least one of the multiple battery blocks may have a contact terminal CT. Alternatively, all battery blocks BB may not have contact terminals CT, and the battery power supply device 1 may not have a ground terminal TE.

The touch panel display 4 corresponds to an example of an operation reception unit. The touch panel display 4 receives an operation input from a user to specify at least one of the battery blocks BB1 to BBN. The touch panel display 4 also displays information in response to a control signal from the control unit 3. Note that the operation reception unit is not limited to a touch panel display, and may be various operation input devices such as a push button switch.

The control unit 3 is configured using, for example, a CPU (Central Processing Unit) that performs predetermined arithmetic processing, a RAM (Random Access Memory) that temporarily stores data, a non-volatile storage device such as a flash memory, and peripheral circuits thereof. The control unit 3 functions as an attachment/detachment control unit 31, an SOC acquisition unit 32, a charge control unit 33, and a discharge control unit 34, for example, by executing a program stored in the above-mentioned storage device.

The attachment/detachment control unit 31 can control each battery block BB to an attached state in which the bypass switching element BS is turned off and the series switching element SS is turned on, and to a detached state in which the series switching element SS is turned off and the bypass switching element BS is turned on. The example shown in FIG. 1 illustrates a case in which battery blocks BB1, BB3, and BBN are in the attached state and battery block BB2 is in the detached state.

When the designation of a battery block BB is accepted by the touch panel display 4, the attachment/detachment control unit 31 sets the designated battery block BB to a detached state. In addition, when a secondary battery B is attached to a battery block BB from which a secondary battery B has been removed, the attachment/detachment control unit 31 sets the battery block BB to which the secondary battery B has been attached to a joined state.

Whether or not a secondary battery B is attached to each battery block BB may be detected, for example, by the battery power supply device 1 being equipped with a detection unit such as a sensor or switch that detects the presence or absence of a secondary battery B, or the user may operate the touch panel display 4 to input whether or not a secondary battery B is attached to each battery block BB. The attachment/detachment control unit 31 can obtain whether or not a secondary battery B is attached to each battery block BB from the information obtained by these detection units and the touch panel display 4.

Figure 2 is a flowchart showing an example of the process of detachment control by the detachment control unit 31 shown in Figure 1. Hereinafter, the same processes are assigned the same step numbers and their explanations are omitted.

For example, if a secondary battery B is attached to each of the battery blocks BB1 to BBN and all of the battery blocks BB1 to BBN are in a join state, the sum of the output voltages of the secondary batteries B1 to BN is output to the input/output terminals TT1 and TT2. This makes it easy for the battery power supply device 1 to output a high voltage by effectively utilizing the secondary batteries B used in various electrically powered devices.

Then, the detachment control unit 31 checks whether or not the designation of the battery block BB has been accepted by the touch panel display 4 (step S1). If the designation of the battery block BB has been accepted by the touch panel display 4 (YES in step S1), the detachment control unit 31 sets the designated battery block BB to a detached state (step S2) and transitions to step S1 again.

As a result, when a user wants to use an electric bicycle, for example, the user operates the touch panel display 4 to input, for example, "2" as the block number of the battery block BB to which the secondary battery B for the electric bicycle is attached. Then, as shown in FIG. 1, the attachment/detachment control unit 31 turns off the series switching element SS of the specified battery block BB2 and turns on the bypass switching element BS to put it into a detached state (step S2).

With the series switching element SS turned off, the secondary battery B2 is removed from the current path through the series battery module 2, making it possible to remove the secondary battery B2 from the battery block BB2. Meanwhile, with the bypass switching element BS of the battery block BB2 turned on, the series connection of the secondary batteries B1, B3 to BN, excluding the secondary battery B2, is maintained. As a result, the sum of the output voltages of the secondary batteries B1, B3 to BN is output to the input/output terminals TT1 and TT2, making it possible to output a high voltage while allowing the user to remove the desired secondary battery B from the battery power supply device 1. This makes it possible to achieve both high voltage output from the battery power supply device 1 and effective use of the secondary batteries B1 to BN.

On the other hand, if the designation of the battery block BB has not been accepted (NO in step S1), the attachment/detachment control unit 31 checks whether or not a secondary battery B has been attached to the battery block BB from which the secondary battery B was removed (step S3). If the secondary battery B has not been attached (NO in step S3), the attachment/detachment control unit 31 transitions the process back to step S1.

On the other hand, if a secondary battery B is attached to the battery block BB from which the secondary battery B was removed (YES in step S3), the attachment/detachment control unit 31 switches off the bypass switching element BS of the battery block BB to which the secondary battery B was attached and switches on the series switching element SS to place the battery in a joined state (step S4), and the process again transitions to step S1.

As a result, after a user has finished using an electric device such as an electric bicycle, the secondary battery B of the unused electric device can be attached to the series battery module 2, whereby the secondary battery B is connected in series with the other secondary batteries B, and the output voltage of the newly attached secondary battery B is added to the output voltage of the input/output terminals TT1 and TT2. This makes it possible to effectively utilize the secondary battery B of the unused electric device. In addition, as described below, it is also possible to charge the secondary battery B attached to the series battery module 2.

The SOC acquisition unit 32 acquires the SOC (State Of Charge) of the secondary batteries B of each battery block BB. Specifically, for example, an open circuit voltage-SOC characteristic table showing the relationship between the open circuit voltage and SOC of the secondary batteries B1 to BN may be stored in advance in the storage device described above, and the battery power supply device 1 may include a voltage detection unit (not shown) that detects the terminal voltages of the secondary batteries B1 to BN, respectively.

Then, the SOC acquisition unit 32 may acquire the terminal voltage, i.e., the open circuit voltage, detected by the voltage detection unit from the secondary battery B of the battery block BB in the disconnected state, i.e., when the series switching element SS is off and the bypass switching element BS is on, and acquire the SOC associated with the open circuit voltage in the open circuit voltage-SOC characteristics table as the SOC of the secondary battery B.

In addition, for example, the full charge capacities of the secondary batteries B1 to BN may be stored in advance in the storage device described above, and the battery power supply device 1 may include a current detection unit (not shown) that detects the current flowing through the series battery module 2.

The SOC acquisition unit 32 processes, for example, the secondary battery B of the battery block BB in a connected state, i.e., with the bypass switching element BS off and the series switching element SS on, and accumulates the current values detected by the current detection unit, with the current value in the charging direction being positive and the current value in the discharging direction being negative. The SOC acquisition unit 32 may then calculate the SOC of the secondary battery B being processed from the ratio of the charge amount obtained by accumulating the current values to the full charge capacity of the secondary battery B being processed.

When charging the series battery module 2, the charging control unit 33 groups the battery blocks BB1 to BBN with an SOC less than 100% into a first group G1 with a relatively high SOC of the secondary batteries B and a second group G2 with a low SOC of the secondary batteries B. The charging control unit 33 then places the battery blocks BB of the first group G1 with a high SOC in a join state and the battery blocks BB of the second group G2 with a low SOC in a disconnect state, thereby preferentially charging the secondary batteries B of the battery blocks BB of the first group G1 with a high SOC.

The number of battery blocks BB grouped into the first group G1 may be one, and the number of battery blocks BB grouped into the second group G2 may be one.

Figure 3 is a flowchart showing an example of the charging control process by the charging control unit 33 shown in Figure 1. When charging the series battery module 2, for example, the user may connect a charging device (not shown) to the input/output terminals TT1 and TT2, or the user may operate the touch panel display 4 to instruct charging, which causes the charging control unit 33 to connect the charging device (not shown) to the input/output terminals TT1 and TT2.

For example, when the battery power supply device 1 is attached to an electric vehicle, the charging stand corresponds to the charging device, and the charging voltage supplied from the charging stand to the electric vehicle is applied to the input/output terminals TT1 and TT2.

The charging control unit 33 may start the charging control process, for example, in response to an input operation on the touch panel display 4 by a user, may start the charging control process by automatically detecting that a charging device has been connected to the input/output terminals TT1 and TT2, or may start the charging control process in response to a control signal from the outside.

First, the SOC acquisition unit 32 acquires the SOC of each of the secondary batteries B1 to BN (step S11). For ease of explanation, step S11 is described as one step of the charge control process, but the SOC acquisition process by the SOC acquisition unit 32 is constantly performed in parallel with charging and discharging, and the SOC of each of the secondary batteries B1 to BN is constantly updated.

Next, the charging control unit 33 groups the multiple battery blocks BB1 to BBN into group A, where the SOC of the secondary battery B is 100%, and group G, where the SOC of the secondary battery B is less than 100% (step S12).

Next, the charging control unit 33 groups the battery blocks BB of group G whose SOC is less than 100% into a first group G1 in which the SOC of the secondary battery B is relatively high, and a second group G2 in which the SOC of the secondary battery B is relatively low (step S13).

For example, the charging control unit 33 may classify a predetermined number of battery blocks BB in group G in descending order of SOC as a first group G1, and the remaining battery blocks BB as a second group G2. The number may be set appropriately, for example, by the user operating the touch panel display 4. The number may also be set to one. In this case, only the battery block BB with the highest SOC among the battery blocks BB in group G becomes the first group G1.

Next, the charging control unit 33 charges the battery block BB of the first group G1 by putting the battery block BB of the first group G1 in a joining state and putting the battery blocks BB of the second group G2 and group A in a withdrawn state (step S14).

Through steps S11 to S14, secondary batteries B with a relatively high SOC, i.e., batteries that take less time to fully charge, are charged preferentially. As a result, each secondary battery B1 to BN is charged so that the number of fully charged secondary batteries B increases quickly. As the number of fully charged secondary batteries B increases, it becomes easier for a user to remove a fully charged secondary battery B from the battery power supply device 1 and use it when the user needs a secondary battery B to use an electrically powered device. As a result, user convenience is improved.

After that, while charging by the charging device continues, steps S11 to S14 are repeated, and secondary batteries B1 to BN are charged in sequence.

When discharging the series battery module 2, the discharge control unit 34 places the battery block BB, which includes the secondary battery B whose SOC indicates a full charge, in a disconnected state.

Figure 4 is a flowchart showing an example of the discharge control process by the discharge control unit 34 shown in Figure 1. When discharging the series battery module 2, for example, the user may connect a load device (not shown) to the input/output terminals TT1 and TT2, or the user may operate the touch panel display 4 to instruct discharging, causing the charge control unit 33 to connect the load device (not shown) to the input/output terminals TT1 and TT2.

For example, when the battery power supply device 1 is attached to an electric vehicle, the drive motor of the electric vehicle corresponds to the load device, and the input/output terminals TT1 and TT2 may be connected to the load device by control from the electric vehicle side.

The discharge control unit 34 may start the discharge control process, for example, in response to an input operation on the touch panel display 4 by a user, may start the discharge control process by automatically detecting that a load device has been connected to the input/output terminals TT1 and TT2, or may start the discharge control process in response to a control signal from the outside.

First, the SOC of each secondary battery B1 to BN is obtained by step S11 similar to that described above. Next, the discharge control unit 34 executes step S12 similar to that described above, and the battery blocks BB1 to BBN are grouped into group A, which has an SOC of 100%, and group G, which has an SOC of less than 100%.

The charging control unit 33 and the discharging control unit 34 may be configured as an integrated unit, and step S12 may be executed by the charging control unit 33 or by the discharging control unit 34.

Next, the discharge control unit 34 discharges the battery block BB of group G by putting the battery block BB of group G in a joining state and putting the battery block BB of group A in a leaving state (step S21). Thereafter, steps S11 to S21 are repeated while the discharging of the series battery module 2 continues, and the battery block BB of group G is discharged.

By performing the processing in steps S11 to S21, fully charged secondary batteries B are not discharged, so the number of fully charged secondary batteries B is maintained as large as possible. The more fully charged secondary batteries B there are, the easier it is for a user to remove a fully charged secondary battery B from the battery power supply device 1 and use it when the user needs a secondary battery B to use an electrically powered device. As a result, user convenience is improved.

In step S21, the discharge control unit 34 only needs to set the battery block BB of group A to a detached state, and does not necessarily need to set all battery blocks BB of group G to a joined state. The discharge control unit 34 may select a battery block BB from group G to a joined state and set the remaining battery blocks BB to a detached state so that a desired voltage is obtained between the input/output terminals TT1 and TT2.

The battery power supply device 1 may not include the discharge control unit 34, may not include the charge control unit 33, and may not include the SOC acquisition unit 32.

Figure 5 is a conceptual circuit diagram showing a modified example of the series battery module 2. The series battery module 2a shown in Figure 5 includes a battery block BBa instead of the battery block BB. In addition to the battery block BB, the battery block BBa shown in Figure 5 further includes an inversion circuit RC that inverts the polarity of the secondary battery B. The inversion circuit RC is configured, for example, using a series circuit of inversion switching elements SR1 and SR2.

One end of the inverting switching element SR1 is connected to the other end P2, and the other end of the inverting switching element SR1 is connected to one end of the inverting switching element SR2. The other end of the inverting switching element SR2 is connected to the connection point between the first terminal T1 and the series switching element SS.

The connection point P3 between the inversion switching element SR1 and the inversion switching element SR2 is connected to one end P1 of another adjacent battery block BBa that is at a lower potential than the own block. One end P1 and the connection point P3 serve as input/output terminals for each battery block BBa.

In the battery block BBa, the parallel circuit of the intra-block series circuit SC and the bypass switching element BS in each battery block BB are connected in series via the inversion switching element SR1, so that multiple battery blocks BBa are connected in series.

The inversion switching elements SR1 and SR2 may be semiconductor switching elements such as transistors, or may be mechanical relay switches. The inversion switching elements SR1 and SR2 are turned on and off in response to a control signal from the control unit 3.

In addition to the above-mentioned connected and disconnected states, the battery block BBa can be in an inverted state in which the polarity of the secondary battery B is inverted by the reversing circuit RC. In the example shown in FIG. 5, the battery block BB1a is in the connected state, the battery block BB2a is in the disconnected state, and the battery block BB3a is in the inverted state.

When battery block BBa is used, in the added state, the series switching element SS and the inverting switching element SR1 are on, and the bypass switching element BS and the inverting switching element SR2 are off. In the removed state, the bypass switching element BS and the inverting switching element SR1 are on, and the series switching element SS and the inverting switching element SR2 are off. In the inverted state, the bypass switching element BS and the inverting switching element SR2 are on, and the series switching element SS and the inverting switching element SR1 are off. Note that in the removed state, the bypass switching element BS and the inverting switching element SR1 may be off, and the series switching element SS and the inverting switching element SR2 may be on.

In other words, when battery block BBa is used, in steps S2, S4, S14, and S21, and steps S37, S44, S2b, and S4b described below, the inversion switching elements SR1 and SR2 in the join and leave states can be turned on and off as described above.

The output voltage between the input/output terminals TT1 and TT2, i.e., the output voltage of the series battery module 2a, is the sum of the output voltages of the battery blocks BBa in the joined state minus the output voltage of the battery block BBa in the inverted state. Therefore, when the series battery module 2a is used, the discharge control unit 34 increases the degree of freedom in controlling the output voltage of the series battery module 2a by controlling the battery blocks BBa of group G to three states, joined state, inverted state, and removed state, in step S21.

In addition, in the battery power supply device 1, it is sufficient that at least one of the multiple battery blocks has an inversion circuit RC, and the series battery module may be a mixture of battery blocks BB and battery blocks BBa connected in series.

(Second embodiment)

Next, a battery power supply device 1a according to a second embodiment of the present invention will be described. FIG. 6 is a block diagram showing an example of the configuration of the battery power supply device 1a according to the second embodiment of the present invention. The battery power supply device 1a differs from the battery power supply device 1 in that it is provided with temperature sensors (not shown) that measure the temperatures T(1) to T(N) of the secondary batteries B1 to BN, and in that it has a control unit 3a.

The control unit 3a differs from the control unit 3 in that it also functions as a temperature acquisition unit 35, a continuous current-flow time acquisition unit 36, and a continuous pause time acquisition unit 37, and in the operation of the charge control unit 33a and the discharge control unit 34a.

The rest of the configuration is the same as that of the battery power supply device 1, so we will omit the explanation and explain the distinctive features of this embodiment below.

The temperature acquisition unit 35 acquires temperatures T(1) to T(N) measured by the temperature sensors of each battery block BB. Hereinafter, temperatures T(1) to T(N) are collectively referred to as temperature T.

The continuous current flow time acquisition unit 36 acquires the continuous current flow times Pc(1) to Pc(N) of the battery blocks BB1 to BBN. Hereinafter, the continuous current flow times Pc(1) to Pc(N) are collectively referred to as the continuous current flow time Pc.

The continuous current flow times Pc(1) to Pc(N) are the times that the battery blocks BB1 to BBN have been in a joined state, counting back from the current time point. The continuous current flow time acquisition unit 36 can acquire the continuous current flow times Pc(1) to Pc(N) by measuring the times that the battery blocks BB1 to BBN have been in a joined state.

The continuous downtime acquisition unit 37 acquires the continuous downtimes Pd(1) to Pd(N) of the battery blocks BB1 to BBN. Hereinafter, the continuous downtimes Pd(1) to Pd(N) are collectively referred to as the continuous downtime Pd.

The continuous pause times Pd(1) to Pd(N) are the consecutive times that the battery blocks BB1 to BBN have been in a disconnected state, counting back from the current time point. The continuous pause time acquisition unit 37 can acquire the continuous pause times Pd(1) to Pd(N) by measuring the consecutive times that the battery blocks BB1 to BBN have been in a disconnected state.

The charging control unit 33a controls the charging of each battery block BB by controlling the switching of each battery block BB between the joined and unjoined states so as to equalize the SOC of the secondary batteries B of each battery block BB.

The discharge control unit 34a controls the discharge of each battery block BB by controlling the switching of each battery block BB between the joined state and the unjoined state so as to equalize the SOC of the secondary batteries B of each battery block BB.

Figure 7 is a flowchart showing an example of the charging control process by the charging control unit 33a shown in Figure 6. The charging process can be started in the same way as in the case of the charging control unit 33. First, the SOC(1) to SOC(N) of each of the secondary batteries B1 to BN are obtained in step S11 similar to that described above.

The corresponding block numbers are written in parentheses, such as SOC(1) for secondary battery B1, SOC(2) for secondary battery B2, and SOC(N) for secondary battery BN. Similarly, the block numbers of the corresponding battery block BB and secondary battery B are written in parentheses for temperature T, continuous current-carrying time Pc, and continuous resting time Pd.

Next, the temperature acquisition unit 35 acquires the temperatures T(1) to T(N) of the secondary batteries B1 to BN (step S31). Step S31 is always executed in parallel with other processes.

Next, the continuous current flow time acquisition unit 36 acquires the continuous current flow times Pc(1) to Pc(N) of the battery blocks BB1 to BBN (step S32). Step S32 is always executed in parallel with other processes.

Next, the continuous downtime acquisition unit 37 acquires the continuous downtimes Pd(1) to Pd(N) of the battery blocks BB1 to BBN (step S33). If the continuous downtime Pd exceeds a preset upper limit time, for example 60 seconds, the continuous downtime acquisition unit 37 initializes the continuous downtime Pd to zero. Step S33 is always executed in parallel with other processes.

Then, the charging control unit 33a calculates the charging indices Cc(1) to Cc(N) of the battery blocks BB1 to BBN based on the SOC(1) to SOC(N), the temperatures T(1) to T(N), the continuous current-carrying times Pc(1) to Pc(N), and the continuous pause times Pd(1) to Pd(N) (step S34). Hereinafter, the charging indices Cc(1) to Cc(N) are collectively referred to as the charging indices Cc.

If the block number is i, the charging index Cc(i) of the battery block BBi is expressed by the following formula (1).

Charging index Cc (i) = KsSOC (i) + KtT (i) + KcPc (i) + KdPd (i) ... (1)

where SOC(i) is the SOC of the secondary battery Bi, T(i) is the temperature of the secondary battery Bi, Pc(i) is the continuous current-carrying time of the battery block BBi, and Pd(i) is the continuous resting time of the battery block BBi. In addition, Ks is the coefficient of the SOC, Kt is the coefficient of the temperature T, Kc is the coefficient of the continuous current-carrying time Pc, and Kd is the coefficient of the continuous resting time Pd.

The coefficients Ks, Kt, Kc, and Kd can be, for example, Ks = Ds/Ns, Kt = Dt/Nt, Kc = Dc/Nc, and Kd = Dd/Nd. Ns, Nt, Nc, and Nd are normalized numbers, and standard values of SOC, temperature T, continuous current-on time Pc, and continuous pause time Pd can be used.

For example, Ns can be a value between 0 and 100, corresponding to an SOC between 0 and 100%. Nt can be a value between -10 and 50, corresponding to a temperature T between -10°C and 50°C. For the continuous current-carrying time Pc and the continuous pause time Pd, Nc and Nd can be set to 1000 depending on the data processing method for time within the charging control unit 33a. For example, if 1 msec is internally processed as "1" and 1 sec as "1000", Nc and Nd can be set to 1000.

Ds, Dt, Dc, and Dd are weighting numbers, and by increasing the weighting number for the items that you want to have a greater impact on, and decreasing the weighting number for the items that you want to have a smaller impact on, for each of the items SOC, temperature T, continuous current flow time Pc, and continuous rest time Pd, the charging index Cc can be an index that reflects the SOC, temperature T, continuous current flow time Pc, and continuous rest time Pd in a balanced manner.

The coefficients Ks, Kt, Kc, Kd, the weighting numbers Ds, Dt, Dc, Dd, and the normalization numbers Ns, Nt, Nc, Nd may be set appropriately, for example, experimentally.

Next, the charging control unit 33a groups the multiple battery blocks BB1 to BBN into a group A in which the SOC of the secondary battery B is 100% and cannot be charged, and a group G in which the SOC of the secondary battery B is less than 100% and can be charged (step S35).

Next, the charging control unit 33a groups the battery blocks BB of group G with an SOC less than 100% into a first group G1 with a relatively small charging index Cc and a second group G2 with a relatively large charging index Cc (step S36). Specifically, the charging control unit 33a may group a predetermined set number of battery blocks BB of group G in ascending order of charging index Cc into the first group G1, and the remaining battery blocks BB into the second group G2. The set number can be set appropriately, as described above. With the set number set to 1, the charging control unit 33a may group only the battery block BB with the smallest charging index Cc into the first group G1.

Next, the charging control unit 33a charges the battery block BB of the first group G1 by putting the battery block BB of the first group G1 in a joining state and putting the battery blocks BB of the second group G2 and group A in a withdrawn state (step S37).

As described above, steps S34 to S37 allow the charging control unit 33a to control the charging of each battery block BB based on the temperatures T(1) to T(N), the continuous current-carrying times Pc(1) to Pc(N), and the continuous pause times Pd(1) to Pd(N) in addition to the SOC.

The charging index Cc includes the term KsSOC, so it is larger as the SOC is larger and smaller as the SOC is smaller. Therefore, in step S37, charging the battery block BB of the first group G1, which has a relatively small charging index Cc, as a joining state basically means charging the battery block BB with a relatively small SOC.

Therefore, according to steps S34 to S37, the charging control unit 33a can control the charging of each battery block BB by controlling the switching of each battery block BB between the joining state and the withdrawal state so as to equalize the SOC of the secondary batteries B of each battery block BB.

Furthermore, since the charging index Cc includes the term +KtT, the higher the temperature T, the larger it is, and the lower the temperature T, the smaller it is. Therefore, by charging a battery block BB with a relatively small charging index Cc, in addition to the above-mentioned SOC, a battery block BB with a relatively low temperature T is more likely to be charged. A secondary battery B with a high temperature T is more likely to deteriorate, and a secondary battery B with a low temperature T is less likely to deteriorate.

Accordingly, according to steps S34 to S37, the charging control unit 33a can equalize the SOC of the secondary batteries B in each battery block BB while preferentially charging the secondary batteries B that are relatively less susceptible to deterioration, making it easier to reduce deterioration of each secondary battery B.

Furthermore, since the charging index Cc includes the term +KcPc, it is larger the longer the continuous current flow time Pc is, and is smaller the shorter the continuous current flow time Pc is. Therefore, by charging a battery block BB with a relatively small charging index Cc, in addition to the above-mentioned SOC, it becomes easier to charge a battery block BB with a relatively short continuous current flow time Pc.

Secondary batteries B with a long continuous current-carrying time Pc are more susceptible to deterioration, while secondary batteries B with a short continuous current-carrying time Pc are less susceptible to deterioration. Therefore, according to steps S34 to S37, the charging control unit 33a can equalize the SOC of the secondary batteries B in each battery block BB while preferentially charging the secondary batteries B that are relatively less susceptible to deterioration, making it easier to reduce deterioration of each secondary battery B.

As described above, the SOC acquisition unit 32 can use a method of acquiring the SOC of the secondary battery B from the terminal voltage of the secondary battery B in the detached state, i.e., the open circuit voltage, and a method of acquiring the SOC of the secondary battery B indirectly by integrating the charge and discharge currents. The SOC acquired directly from the open circuit voltage is more accurate than the SOC acquired indirectly by integrating the charge and discharge currents.

According to the term KdPd(i) of the charging index Cc(i) shown in formula (1), for a battery block BB in a disconnected state where the SOC can be obtained directly from the open circuit voltage, the longer the continuous pause time Pd during which the disconnected state continues, the larger the charging index Cc(i) becomes, and therefore the more difficult it becomes to charge. When the continuous pause time Pd exceeds the upper limit time described above, the continuous pause time Pd becomes zero, making it easier to charge.

Therefore, if there is no influence of terms other than KdPd(i) of the charging index Cc(i), the battery block BB that is in a disconnected state and from which a highly accurate SOC can be obtained directly from the open circuit voltage will be rotated among the battery blocks BB1 to BBN. As a result, the charging index Cc(i) includes the term KdPd(i), which improves the accuracy of obtaining SOC(1) to SOC(N) by the SOC obtaining unit 32.

Therefore, by appropriately setting the coefficients Ks, Kt, Kc, and Kd, it becomes easy to improve the accuracy of SOC(1) to SOC(N) while balancing the terms other than KdPd(i) with the term KdPd(i).

The battery power supply device 1a may not include the temperature acquisition unit 35, the continuous current-flow time acquisition unit 36, and the continuous pause time acquisition unit 37, and may not execute steps S31 to S33. The charging index Cc(i) may not include the terms KtT(i), KcPc(i), and KdPd(i), and the SOC(i) may be used as the charging index Cc(i) as is. When the SOC(i) is used as the charging index Cc(i) as is, the charging control unit 33a can control the charging of each battery block BB by controlling the switching between the joining state and the separation state of each battery block BB so as to equalize the SOC of each secondary battery B without being influenced by parameters other than the SOC.

Also, the battery power supply device 1a may not have a temperature acquisition unit 35, may not execute step S31, and the charging index Cc(i) may not include a term for KtT(i). Alternatively, the battery power supply device 1a may not have a continuous current-carrying time acquisition unit 36, may not execute step S32, and the charging index Cc(i) may not include a term for KtT(i). Alternatively, the battery power supply device 1a may not have a continuous pause time acquisition unit 37, may not execute step S33, and the charging index Cc(i) may not include a term for KdPd(i).

Figure 8 is a flowchart showing an example of the discharge control process by the discharge control unit 34a shown in Figure 6. The discharge process can be started in the same way as in the case of the discharge control unit 34. First, SOC(1) to SOC(N) are acquired in step S11 as described above, temperatures T(1) to T(N) are acquired in step S31, continuous current application times Pc(1) to Pc(N) are acquired in step S32, and continuous pause times Pd(1) to Pd(N) are acquired in step S33.

Then, the charge control unit 33a calculates the discharge indices Cd(1) to Cd(N) of the battery blocks BB1 to BBN based on the SOC(1) to SOC(N), the temperatures T(1) to T(N), the continuous current-carrying times Pc(1) to Pc(N), and the continuous pause times Pd(1) to Pd(N) (step S41). Hereinafter, the discharge indices Cd(1) to Cd(N) are collectively referred to as the discharge index Cd.

If the block number is i, the discharge index Cd(i) of battery block BBi is expressed by the following formula (2).

Discharge index Cd(i)=Ks(100-SOC(i))+KtT(i)+KcPc(i)+KdPd(i)...(2)

Equation (2) differs from equation (1) in that the term KsSOC(i) is replaced with Ks(100-SOC(i)). In other words, the discharge index Cd(i) is an index that, unlike the charge index Cc(i), becomes smaller as the SOC increases and becomes larger as the SOC decreases.

Next, the discharge control unit 34a groups the battery blocks BB1 to BBN into group A, which cannot be discharged because the SOC of the secondary battery B is 0%, and group G, which can be discharged because the SOC of the secondary battery B is greater than 0% (step S42).

Next, the discharge control unit 34a selects battery blocks BB in group G whose SOC exceeds 0%.

The battery blocks BB are grouped into a first group G1 having a relatively small discharge index Cd and a second group G2 having a relatively large discharge index Cd (step S43). Specifically, the discharge control unit 34a may group a predetermined set number of battery blocks BB in group G in ascending order of discharge index Cd into the first group G1, and the remaining battery blocks BB into the second group G2. The set number can be set appropriately, as described above. With the set number set to 1, the discharge control unit 34a may group only the battery block BB in group G having the smallest charge index Cc into the first group G1.

Next, the discharge control unit 34a discharges the battery block BB of the first group G1 by putting the battery block BB of the first group G1 in a joining state and putting the battery blocks BB of the second group G2 and group A in a withdrawn state (step S44).

As described above, steps S41 to S44 allow the discharge control unit 34a to control the discharge of each battery block BB based on the temperatures T(1) to T(N), the continuous current-carrying times Pc(1) to Pc(N), and the continuous pause times Pd(1) to Pd(N) in addition to the SOC.

The discharge index Cd includes the term Ks(100-SOC(i)), so the larger the SOC, the smaller the discharge index Cd, and the smaller the SOC, the larger the discharge index Cd. Therefore, discharging a battery block BB with a relatively small discharge index Cd in step S44 basically means discharging a battery block BB with a relatively large SOC.

Therefore, according to steps S41 to S44, the discharge control unit 34a can control the discharge of each battery block BB by controlling the switching of each battery block BB between the joining state and the withdrawal state so as to equalize the SOC of the secondary batteries B in each battery block BB.

The effect of including +KtT(i), +KcPc(i), and +KdPd(i) in the discharge index Cd(i) is similar to that of the charge index Cc(i) described above, so the explanation will be omitted.

In step S44, the discharge control unit 34a only needs to set the battery blocks BB of the second group G2 and group A to a detached state, and does not necessarily need to set all battery blocks BB of the first group G1 to a joined state. The discharge control unit 34a may select battery blocks BB from the first group G1 to a joined state and set the remaining battery blocks BB to a detached state so that the desired voltage is obtained between the input/output terminals TT1 and TT2.

The battery power supply device 1a may not include the temperature acquisition unit 35, the continuous current-flow time acquisition unit 36, and the continuous pause time acquisition unit 37, and may not execute steps S31 to S33. The discharge index Cd(i) may not include the terms KtT(i), KcPc(i), and KdPd(i), and the SOC(i) may be used as the discharge index Cd(i) as it is. When the SOC(i) is used as the discharge index Cd(i) as it is, the discharge control unit 34a can control the discharge of each battery block BB by controlling the switching between the joining state and the withdrawal state of each battery block BB so as to equalize the SOC of each secondary battery B without being influenced by parameters other than the SOC.

Also, the battery power supply device 1a may not have a temperature acquisition unit 35, may not execute step S31, and the discharge index Cd(i) may not include the term KtT(i). Alternatively, the battery power supply device 1a may not have a continuous current-carrying time acquisition unit 36, may not execute step S32, and the discharge index Cd(i) may not include the term KtT(i). Alternatively, the battery power supply device 1a may not have a continuous pause time acquisition unit 37, may not execute step S33, and the discharge index Cd(i) may not include the term KdPd(i).

The battery power supply device 1a may also include a series battery module 2a instead of the series battery module 2, and a battery block BBa instead of the battery block BB. When charging the series battery module 2a, the inverted battery block BBa is discharged while the added battery block BBa is being charged. In other words, within the series battery module 2a, the charge amount can be transferred from the inverted battery block BBa to the added battery block BBa.

Therefore, when the series battery module 2a is used, the charging control unit 33a may invert the battery blocks BBa of the second group G2 and group A in step S37. By inverting the battery blocks BBa of the second group G2 and group A, the charge amount is transferred from the battery blocks BBa of the second group G2 and group A, which have a larger SOC, to the battery blocks BBa of the first group G1, which have a smaller SOC. As a result, the SOC of each secondary battery B can be equalized more quickly.

In addition, when the series battery module 2a is used, the discharge control unit 34a may place at least one of the battery blocks BBa of the second group G2 and group A in an inverted state in step S44. In this way, it is possible to discharge at least one of the battery blocks BBa of the first group G1, which has a high SOC, while charging at least one of the battery blocks BBa of the second group G2 and group A, which has a low SOC. As a result, it is possible to more quickly equalize the SOC of each secondary battery B.

In the battery power supply unit 1a, as in the case of the battery power supply unit 1, the series battery module may be a mixture of battery blocks BB and battery blocks BBa connected in series.

(Third embodiment)

Next, a battery power supply device 1b according to a third embodiment of the present invention will be described. FIG. 9 is a block diagram showing an example of the configuration of the battery power supply device 1b according to the third embodiment of the present invention. The battery power supply device 1b differs from the battery power supply device 1 in that it further includes a ground terminal TE, that it includes a series battery module 2b instead of the series battery module 2, and that the operation of the attachment/detachment control unit 31b is different.

The rest of the configuration is the same as that of the battery power supply device 1, so we will omit the explanation and explain the distinctive features of this embodiment below.

Series battery module 2b has battery blocks BB1b to BBNb instead of battery blocks BB1 to BBN. Hereinafter, battery blocks BB1b to BBNb will be collectively referred to as battery block BBb.

Battery block BBb differs from battery block BB in that it further includes a ground switching element SE, and the intra-block series circuit SC of battery block BBb further includes a disconnect switching element SD. In other respects, battery block BBb is configured in the same way as battery block BB.

The ground switching element SE is disposed between the second terminal T2 of each battery block BBb and the ground terminal TE. The ground switching element SE may be disposed between the first terminal T1 and the ground terminal TE instead of the second terminal T2.

A disconnection switching element SD is added to the intra-block series circuit SC of the battery block BBb. The disconnection switching element SD is connected in series to the secondary battery B on the opposite side to the series switching element SS.

The ground switching element SE and the disconnection switching element SD may be semiconductor switching elements such as transistors, or may be mechanical relay switches. The ground switching element SE and the disconnection switching element SD are turned on and off in response to a control signal from the control unit 3b.

In addition to performing the same processing as the detachment control unit 31, when the designation of battery block BBb is accepted by the touch panel display 4, the detachment control unit 31b places the designated battery block BBb in a detached state, thereby turning off the series switching element SS of the battery block BBb, and further turning off the disconnection switching element SD and turning on the ground switching element SE of the battery block BBb.

In addition, when a secondary battery B is attached to the battery block BBb from which the secondary battery B has been removed, the attachment/detachment control unit 31b turns off the ground switching element SE and turns on the disconnect switching element SD of the battery block BBb to which the secondary battery B is attached, and further places the battery block BBb in a connected state.

Figure 10 is a flowchart showing an example of the process of detachment control by the detachment control unit 31b shown in Figure 9. Figure 9 shows an example in which battery blocks BB1b to BBNb are in a joined state. The detachment control will be explained using an example in which secondary battery B2 of battery block BB2b is removed from this state.

First, the detachment control unit 31b checks whether the designation of the battery block BBb has been accepted by the touch panel display 4 (step S1b). If the designation of the battery block BBb has been accepted by the touch panel display 4 (YES in step S1b), the detachment control unit 31b turns off the series switching element SS of the designated battery block BBb and turns on the bypass switching element BS to put the designated battery block BBb into a detached state (step S2b).

Next, the detachment control unit 31b turns off the disconnect switching element SD and turns on the ground switching element SE of the specified battery block BBb (step S51), and then transitions to step S1b again.

As a result, when a user wants to use an electric bicycle, for example, the user operates the touch panel display 4 to input, for example, "2" as the block number of the battery block BBb in which the secondary battery B for the electric bicycle is installed.

Figure 11 is an explanatory diagram for explaining steps S2b and S51. As shown in Figure 11, when battery block BB2b is specified, steps S2b and S51 turn off the series switching element SS, turn on the bypass switching element BS, turn off the disconnection switching element SD, and turn on the ground switching element SE of battery block BB2b, as shown in Figure 11.

In the state shown in FIG. 9 before steps S2b and S51 are executed, a current flows through the secondary battery B2, and secondary batteries B3 to BN, which are at a lower potential than battery block BB2b, are connected in series to the second terminal T2 of battery block BB2b, and a high voltage is applied to the second terminal T2 of battery block BB2b, which is the sum of the output voltages of secondary batteries B3 to BN. Therefore, if a user attempts to remove secondary battery B2 from battery block BB2b in this state, there is a risk of electric shock due to the current and high voltage.

On the other hand, in the state shown in FIG. 11 after steps S2b and S51 have been executed, the series switching element SS and the disconnection switching element SD of the battery block BB2b are turned off, so that the current flowing through the secondary battery B2 is zero and the secondary battery B2 is in an electrically floating state. In this state, the ground switching element SE of the battery block BB2b is turned on, and the second terminal T2 is electrically connected to the ground terminal TE, so that the secondary battery B2 is at ground potential.

In this way, the current flowing through secondary battery B2 becomes zero and secondary battery B2 is set to ground potential, improving the safety of a user who attempts to remove secondary battery B2.

On the other hand, if the designation of battery block BBb has not been accepted (NO in step S1b), the attachment/detachment control unit 31b checks whether or not a secondary battery B has been attached to the battery block BBb from which the secondary battery B was removed (step S3). If the secondary battery B has not been attached (NO in step S3), the attachment/detachment control unit 31b transitions the process to step S1b again.

On the other hand, if a secondary battery B is attached to the battery block BBb from which the secondary battery B was removed (YES in step S3), the attachment/detachment control unit 31b turns off the ground switching element SE and turns on the disconnect switching element SD of the battery block BBb to which the secondary battery B was attached (step S52). This causes the secondary battery B to be disconnected from the ground terminal TE.

Next, the attachment/detachment control unit 31b switches off the bypass switching element BS of the battery block BBb to which the secondary battery B is attached and switches on the series switching element SS to place the battery block in a connected state (step S4b), and then transitions to step S1b again. This makes the attached secondary battery B available for use.

Note that it is not necessary to execute steps S3, S52, and S4b, and step S1b may be repeated if step S1b is NO. Also, the control unit 3b may further include a temperature acquisition unit 35, a continuous current-flow time acquisition unit 36, and a continuous pause time acquisition unit 37, and may include a charge control unit 33a and a discharge control unit 34a instead of the charge control unit 33 and the discharge control unit 34. Also, the battery block BBb may not include contact terminals CT.

Furthermore, at least one of the battery blocks of the series battery module 2b may be battery block BBb, and the series battery module may be a mixture of battery blocks BB and BBb connected in series.

Figure 12 is a conceptual circuit diagram showing a modified example of series battery module 2b. As shown in Figure 12, series battery module 2c may include battery block BBc instead of battery block BBb in series battery module 2b. Battery block BBc shown in Figure 12 further includes an inversion circuit RC in addition to battery block BBb. The connection wiring of the inversion circuit RC in series battery module 2c is similar to the connection wiring of the inversion circuit RC in series battery module 2a shown in Figure 5, and therefore description thereof will be omitted.

In the example shown in FIG. 5, battery block BB1c is in the connected state, battery block BB2c is in the disconnected state, and battery block BB3c is in the inverted state. By using the series battery module 2c, the same effect as the series battery module 2a can be obtained.

In the battery power supply unit 1b, as in the case of the battery power supply unit 1, the series battery module may be a mixture of battery blocks BBb and BBc connected in series. Also, in the battery power supply units 1, 1a, and 1b, the series battery module may be a mixture of battery blocks BB, BBa, BBb, and BBc connected in series.

1, 1a, 1b Battery power supply device 2, 2a, 2b Series battery module 3, 3a, 3b Control unit 4 Touch panel display (operation reception unit)
31, 31b Attachment/detachment control unit 32 SOC acquisition unit 33, 33a Charging control unit 34, 34a Discharging control unit 35 Temperature acquisition unit 36 Continuous current-flow time acquisition unit 37 Continuous pause time acquisition unit B, B1 to BN Secondary batteries BB, BB1 to BBN, BBa, BB1a to BBNa, BBb, BB1b to BBNb, BBc, BB1c to BBNc Battery block BS Bypass switching element Cc Charging index Cd Discharging index CT Contact terminals A, G Group G1 First group G2 Second group Ks, Kt, Kc, Kd Coefficients Ns, Nt, Nc, Nd Normalized number P1 One end P2 Other end Pc Continuous current-flow time Pd Continuous pause time RC Inverting circuit SC In-block series circuit SD Switching switching element SE Grounding switching elements SR1, SR2 Inverting switching element SS Series switching element T Temperature T1 First terminal T2 Second terminal TE Ground terminals TT1, TT2 Input/output terminals

Claims (15)

a series battery module in which a plurality of battery blocks are connected in series;
a detachment control unit that controls the attachment and detachment of the battery block;
an operation receiving unit that receives a user's designation of the battery block;
Each of the battery blocks is
A first terminal connectable to one electrode of a secondary battery;
a second terminal connectable to the other electrode of the secondary battery;
a series switching element connected in series with the secondary battery connected to the first and second terminals;
a bypass switching element connected in parallel to an intra-block series circuit in which the secondary battery and the series switching element are connected in series,
At least one of the plurality of battery blocks is capable of detachably mounting the secondary battery,
the series battery module is configured such that the plurality of battery blocks are connected in series by connecting in series the intra-block series circuit and the parallel circuit of the bypass switching element in each of the battery blocks;
The attachment/detachment control unit is capable of controlling each of the battery blocks to an attachment state in which the bypass switching element is turned off and the series switching element is turned on, and a detached state in which the series switching element is turned off and the bypass switching element is turned on, and when the designation of the battery block is accepted by the operation accepting unit, the battery power supply device puts the specified battery block into the detached state. A ground terminal for grounding is further provided,
At least one of the plurality of battery blocks further includes a ground switching element interposed between one of the first and second terminals and the ground terminal;
the intra-block series circuit of the battery block including the ground switching element further includes a disconnection switching element connected in series to the secondary battery on the opposite side to the series switching element,
The battery power supply device of claim 1, wherein when the operation receiving unit receives designation of a battery block including the ground switching element, the detachment control unit turns off the series switching element by putting the specified battery block into the detached state, and further turns off the separation switching element and turns on the ground switching element. The battery power supply device according to claim 2, wherein the attachment/detachment control unit further turns off the ground switching element and turns on the disconnect switching element of the battery block to which the secondary battery is attached when the secondary battery is attached to the battery block from which the secondary battery has been removed. The battery power supply device according to claim 3, wherein the attachment/detachment control unit further sets the battery block to which the secondary battery is attached to the joined state when the secondary battery is attached to the battery block from which the secondary battery has been removed. A ground terminal for grounding is further provided,
2. The battery power supply device according to claim 1, wherein at least one of the plurality of battery blocks further comprises a contact terminal capable of coming into contact with a housing of the secondary battery and electrically connected to the ground terminal. an SOC acquisition unit that acquires an SOC of a secondary battery of each of the battery blocks;
2. The battery power supply device of claim 1, further comprising a charge control unit that, when charging the series battery module, groups battery blocks among the plurality of battery blocks in which the SOC of the secondary battery is less than 100% into a first group in which the SOC of the secondary battery is relatively high and a second group in which the SOC of the secondary battery is relatively low, and sets the battery blocks of the first group to the added state and the battery blocks of the second group to the removed state, thereby preferentially charging the battery blocks of the first group. The battery power supply device according to claim 6, wherein the charging control unit selects a battery block having the highest SOC among the battery blocks whose SOC is less than 100% as the first group. an SOC acquisition unit that acquires an SOC of a secondary battery of each of the battery blocks;
2 . The battery power supply device according to claim 1 , further comprising a discharge control unit that, when discharging the series battery module, places the battery block including a secondary battery whose SOC indicates full charge in the detached state. an SOC acquisition unit that acquires an SOC of a secondary battery of each of the battery blocks;
2. The battery power supply device of claim 1, further comprising a charging control unit that controls the charging of each of the battery blocks by controlling the switching of each of the battery blocks between the joining state and the separation state so as to equalize the SOC of the secondary batteries of each of the battery blocks. The battery power supply device according to claim 9, wherein the charging control unit controls the charging of each battery block based on at least one of the following in addition to the SOC: the temperature of the secondary battery of each battery block; the continuous current-on time, which is the continuous time that each battery block has been in a connected state going back from the current time; and the continuous pause time, which is the continuous time that each battery block has been in a disconnected state going back from the current time. an SOC acquisition unit that acquires an SOC of a secondary battery of each of the battery blocks;
The battery power supply device of claim 1, further comprising a discharge control unit that controls the discharging of each of the battery blocks by controlling the switching of each of the battery blocks between the joining state and the withdrawal state so as to equalize the SOC of the secondary batteries of each of the battery blocks. The battery power supply device according to claim 11, wherein the discharge control unit controls the discharge of each battery block based on at least one of the following in addition to the SOC: the temperature of the secondary battery of each battery block; the continuous current-on time, which is the continuous time that each battery block has been in a connected state going back from the current time; and the continuous pause time, which is the continuous time that each battery block has been in a disconnected state going back from the current time. The battery power supply device according to any one of claims 1 to 12, wherein at least one of the plurality of battery blocks further comprises an inversion circuit that inverts the polarity of the secondary battery. The battery power supply device according to any one of claims 1 to 12, wherein each of the secondary batteries is a battery pack for an electrically powered device. The battery power supply device according to any one of claims 1 to 12, further comprising a plurality of the secondary batteries.

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