JP7685932B2 - Battery Management System - Google Patents

Description

The present invention relates to a battery management system.

For example, a battery pack used in an electric vehicle is known. The battery pack includes multiple battery cells connected in series. Also known is a battery management LSI (Large Scale Integration) that manages the state of each battery cell included in the battery pack. The battery management LSI is provided with multiple monitor terminals, and each battery cell included in the battery pack is connected to each monitor terminal.

Patent document 1 describes a battery pack that boots when connected to an external device and shuts down when the connection to the external device is released. Patent document 2 describes a power supply device that includes a cell controller that detects the state of battery cells that make up a battery block and eliminates imbalances in the charging states of the battery cells, and a control device that switches the cell controller to a low power consumption state. Patent document 3 describes equalizing the voltage of a battery pack in a battery system in which multiple battery packs, each of which is made up of multiple unit batteries connected in series, are connected in parallel.

International Publication No. 2019/088430 JP 2009-17657 A JP 2014-103804 A

However, when some of the battery cells in the battery pack are removed or newly installed, it is necessary to properly rewire between the monitor terminals of the battery management LSI and each battery cell in the battery pack. The maximum number of battery cells that can be connected and the minimum voltage to be applied are predefined in the battery management LSI specifications. Therefore, when some of the battery cells in the battery pack are removed or newly installed, it is necessary to rewire between the monitor terminals of the battery management LSI and each battery cell in the battery pack in accordance with the specifications, which makes the work complicated. Furthermore, depending on the environment in which the battery management LSI and the battery pack are placed, there is a possibility that incorrect connections may occur.

The present invention has been made in consideration of the above, and aims to provide a battery management system that can easily and accurately connect a battery pack and a battery management device.

In order to solve the above problems and achieve the object, the battery management system of the present invention includes a battery pack having N holders (N is an integer of 2 or more) each of which detachably holds a battery cell, and which connects the battery cells held by the N holders in series; M battery management devices (M is an integer of 1 or more) each of which is connected to a cell unit, which is a set of two or more battery cells connected in series, and which manages the state of each battery cell included in the cell unit; a connection device that can switch and connect the battery cells held by each of the N holders to one of the M battery management devices; and a control device that detects a plurality of valid holders that hold battery cells among the N holders, and switches and controls the connection device based on the positions of the plurality of valid holders so that the cell unit is connected to one of the M battery management devices according to a predetermined connection rule.

The present invention allows for easy and accurate connection between the battery pack and the battery management device.

FIG. 1 is a diagram showing the configuration of a battery management system. FIG. 2 is a diagram for explaining an example of a connection rule for the battery management unit. FIG. 3 is a diagram illustrating an example of the configuration of a connection device. FIG. 4 is a flowchart showing the flow of processing by the control device. FIG. 5 is a diagram showing a first connection example by a connection device. FIG. 6 is a diagram showing a second connection example by a connection device. FIG. 7 is a diagram showing a third connection example using a connection device.

The following describes the embodiment with reference to the drawings.

Figure 1 is a diagram showing a battery management system 10 according to a first embodiment. The battery management system 10 is provided, for example, in a vehicle. The battery management system 10 may supply power to other devices in addition to the vehicle.

The battery management system 10 includes a battery pack 20, M (M is an integer equal to or greater than 1) battery management devices 22, a connection device 24, and a control device 26.

The battery pack 20 includes multiple battery cells 30 connected in series and generates DC power. For example, the battery pack 20 generates power for driving a vehicle motor. Each of the multiple battery cells 30 is a secondary battery.

The battery pack 20 has N holders 32 (N is an integer equal to or greater than 2). Each of the N holders 32 detachably holds a battery cell 30.

The battery pack 20 connects in series a number of battery cells 30 held by N holders 32. Note that some of the N holders 32 may not hold a battery cell 30. When each of the N holders 32 does not hold a battery cell 30, it shorts between a contact with the positive terminal of the battery cell 30 and a contact with the negative terminal of the battery cell 30. This allows the battery pack 20 to connect in series a number of battery cells 30 held by the N holders 32 that is less than N, even if some of the N holders 32 do not have a battery cell 30 attached.

Such a battery pack 20 allows some of the battery cells 30 to be removed, some of the battery cells 30 to be replaced, and new battery cells 30 to be added to the battery cells 30. This allows the battery pack 20 to use the battery cells 30 efficiently, since it is not necessary to replace all of the battery cells 30 held in the battery pack 20 when some of the battery cells 30 deteriorate or break down.

Each of the M battery management devices 22 is connected to a cell unit, which is a set of two or more battery cells 30. The cell unit is a part of the multiple battery cells 30 held by the battery pack 20, and is composed of two or more battery cells 30 connected in series. For example, the multiple battery cells 30 held by the battery pack 20 are divided into two or more blocks, and each block constitutes a cell unit. Note that the cell unit may be composed of all of the multiple battery cells 30 held by the battery pack 20.

Each cell unit is associated with one of the M battery management devices 22. Each of the M battery management devices 22 is connected to a corresponding cell unit by a connection device 24, and manages the state of each battery cell 30 included in the connected cell unit. For example, each of the M battery management devices 22 detects the voltage of each battery cell 30 included in the connected cell unit. In addition, each of the M battery management devices 22 performs cell balance control so that the charge state of each battery cell 30 included in the connected cell unit is uniform.

In addition, when two or more cell units are connected to two or more battery management devices 22, the two or more battery management devices 22 may cooperate with each other to manage the state of the two or more cell units connected in series. For example, the two or more battery management devices 22 may perform cell balance control so that the charge states of the battery cells 30 included in the two or more cell units are uniform.

Furthermore, each of the M battery management devices 22 has a plurality of monitor terminals 34 to which the battery cells 30 are connected. In each of the M battery management devices 22, the battery cells 30 are connected to the respective plurality of monitor terminals 34 in accordance with a predetermined connection rule. An example of the connection rule will be described later with reference to FIG. 2.

The connection device 24 can switch and connect the battery cells 30 held by each of the N holders 32 of the battery pack 20 to any of the M battery management devices 22. For example, the connection device 24 is a matrix switch that can connect each of the N holders 32 of the battery pack 20 to each of the multiple monitor terminals 34 of the M battery management devices 22 in any combination. That is, the connection device 24 can connect each of the multiple battery cells 30 held by the N holders 32 to any of the multiple monitor terminals 34 of the M battery management devices 22. The connection device 24 connects one battery cell 30 to one monitor terminal 34, and does not connect two or more battery cells 30 at the same time.

The control device 26 controls the switching of the connection state of the connection device 24 when some of the multiple battery cells 30 included in the battery pack 20 are removed, some of the multiple battery cells 30 are replaced, or a new battery cell 30 is added to the multiple battery cells 30. The control device 26 may also control the switching of the connection state of the connection device 24 when a specified event occurs, for example, at startup.

When controlling the switching of the connection state of the connection device 24, the control device 26 detects a plurality of valid holders that hold battery cells 30 among the N holders 32 included in the battery pack 20. For example, the control device 26 may detect the valid holders that hold the battery cells 30 by detecting the voltage of each of the N holders 32 included in the battery pack 20.

Then, the control device 26 controls the connection device 24 to switch based on the positions of the detected multiple valid holders so that each cell unit is connected to one of the M battery management devices 22 according to a predetermined connection rule. More specifically, the control device 26 divides the multiple battery cells 30 included in the battery pack 20 into one or more cell units according to the connection rule based on the positions of the multiple valid holders. Then, the control device 26 associates each of the one or more cell units with one of the M battery management devices 22. Then, the control device 26 controls the connection device 24 to switch so that each of the multiple battery cells 30 is connected to one of the multiple monitor terminals 34 of the corresponding battery management device 22 according to the connection rule.

This allows the M battery management devices 22 to appropriately manage the state of each of the multiple battery cells 30 included in the battery pack 20.

Figure 2 is a diagram for explaining an example of connection rules for M battery management devices 22. For example, the maximum number of battery cells 30 that can be connected to each of the M battery management devices 22 is determined as one of the connection rules. Therefore, each of one or more cell units is set so that the number of battery cells 30 included is equal to or less than the maximum number that can be connected to the corresponding battery management device 22. For example, in the example of Figure 2, the maximum number of battery cells 30 that can be connected to the battery management device 22 is four. Note that the maximum number of battery cells 30 that can be connected to the battery management device 22 is not limited to four and may be another number.

As another example, a minimum input voltage to be applied to each of the M battery management devices 22 is determined as one of the connection rules. Therefore, each of one or more cell units is set so that the voltage it generates is equal to or greater than the minimum input voltage to be applied to the corresponding battery management device 22.

As another example, the multiple monitor terminals 34 of each of the M battery management devices 22 are ranked in ascending order according to the magnitude of the voltage applied. Then, for each of the M battery management devices 22, a connection rule is set so that a voltage is applied to each of the multiple monitor terminals 34 in ascending order according to the order. Also, as another example, the connection rule is set so that a certain voltage is applied to each of the multiple monitor terminals 34 of each of the M battery management devices 22. Also, as another example, the connection rule is set so that the same voltage may be applied to two or more monitor terminals 34 of adjacent orders. Therefore, when the connection device 24 follows such a connection rule, a voltage is applied to each of the multiple monitor terminals 34 of each of the M battery management devices 22 in ascending order according to the order, and some voltage is applied to each of the multiple monitor terminals 34 of each of the M battery management devices 22.

For example, each of the multiple monitor terminals 34 is connected to either the negative terminal of the battery cell 30 located on the most negative side in the cell unit to be connected, or the positive terminal of each battery cell 30 in the cell unit to be connected. For example, in the example of FIG. 2, each of the M battery management devices 22 has five monitor terminals 34. The monitor terminal 34 with the lowest ranking (In0) among the five monitor terminals 34 is connected to the negative terminal of the battery cell 30 located on the most negative side in the cell unit to be connected.

The monitor terminals 34 with ranks other than the lowest rank (In1, In2, In3, In4) among the five monitor terminals 34 are connected to the positive terminals of the battery cells 30 in the cell unit to be connected. The monitor terminal 34 with the highest rank (In4) among the five monitor terminals 34 is connected to the positive terminal of the battery cell 30 located on the most positive side in the cell unit to be connected.

In the example of FIG. 2, if the above-mentioned connection rules are followed, the connection device 24 connects the negative and positive terminals of one battery cell 30 between two monitor terminals 34 of adjacent ranks. Also, if the number of battery cells 30 included in the cell unit to be connected is less than the maximum number that can be connected to the corresponding battery management device 22, the connection device 24 shorts between any two monitor terminals 34 of adjacent ranks.

The M battery management units 22 cooperate with each other to manage the states of two or more cell units connected in series. In this case, the highest-ranked monitor terminal 34 (In4) of the battery management unit 22 located on the low-potential side of two adjacent battery management units 22 is connected to the lowest-ranked monitor terminal 34 (In0) of the battery management unit 22 located on the high-potential side.

Figure 3 shows an example of the configuration of the connection device 24 together with the battery pack 20 and the battery management device 22. As an example, the connection device 24 has N switch circuits 42 and multiple short circuits 44. The N switch circuits 42 correspond one-to-one to the N holders 32 of the battery pack 20. Each of the N switch circuits 42 can switch and connect the target battery cell 30 held by the corresponding holder 32 to one of the multiple monitor terminals 34 of each of the M battery management devices 22.

For example, each of the N switch circuits 42 includes an input relay circuit 52 and a number of output relay circuits 54.

The input relay circuit 52 switches whether or not the target battery cell 30 is connected to any of the M battery management devices 22. For example, when the corresponding holder 32 does not hold a battery cell 30, the input relay circuit 52 is turned off by the control device 26 and does not connect the corresponding holder 32 to any of the battery management devices 22. When the corresponding holder 32 holds a battery cell 30, the input relay circuit 52 is turned on by the control device 26 and connects the battery cell 30 held by the corresponding holder 32 to one of the battery management devices 22.

In this embodiment, the input relay circuit 52 includes a first input terminal 62, a second input terminal 64, a first output terminal 66, a second output terminal 68, a first switch 72, and a second switch 74. The first input terminal 62 is connected to the positive terminal of the target battery cell 30. The second input terminal 64 is connected to the negative terminal of the target battery cell 30. The first switch 72 turns on or off between the first input terminal 62 and the first output terminal 66. The second switch 74 turns on or off between the second input terminal 64 and the second output terminal 68. The first switch 72 and the second switch 74 operate in synchronization with each other. When the battery cell 30 is held in the corresponding holder 32, the control device 26 turns on the first switch 72 and the second switch 74, and when the battery cell 30 is not held in the corresponding holder 32, the control device 26 turns off the first switch 72 and the second switch 74.

Each of the N switch circuits 42 includes a plurality of output relay circuits 54, the number of which is equal to the number of battery cells 30 that can be managed by the M battery management devices 22. Each of the plurality of output relay circuits 54 corresponds to a monitor terminal 34 of one of the M battery management devices 22. That is, the plurality of output relay circuits 54 are provided corresponding to all of the monitor terminals 34 of the M battery management devices 22. Each of the plurality of output relay circuits 54 switches whether or not to connect the input relay circuit 52 to the corresponding monitor terminal 34.

In this embodiment, the multiple output relay circuits 54 are provided for each of the M battery management devices 22 in correspondence with the multiple monitor terminals 34 excluding the lowest-ranked monitor terminal 34. Also, in this embodiment, each of the multiple output relay circuits 54 includes a third input terminal 82, a fourth input terminal 84, a third output terminal 86, a fourth output terminal 88, a third switch 92, and a fourth switch 94.

The third input terminal 82 is connected to the first output terminal 66 of the input relay circuit 52. The fourth input terminal 84 is connected to the second output terminal 68 of the input relay circuit 52. The third output terminal 86 is connected to the corresponding monitor terminal 34. The fourth output terminal 88 is connected to the monitor terminal 34 that is one rank lower than the corresponding monitor terminal 34. The third switch 92 turns on or off between the third input terminal 82 and the third output terminal 86. The fourth switch 94 turns on/off between the fourth input terminal 84 and the fourth output terminal 88. The third switch 92 and the fourth switch 94 operate in sync.

When the control device 26 is to detect the voltage of the battery cell 30 through the corresponding monitor terminal 34, it turns on the third switch 92 and the fourth switch 94, and when the control device 26 is not to detect the voltage of the battery cell 30 through the corresponding monitor terminal 34, it turns off the third switch 92 and the fourth switch 94. Note that for each of the N switch circuits 42, the control device 26 turns on only one of the multiple output relay circuits 54 and turns off the other output relay circuits 54. Also, the control device 26 may turn off all output relay circuits 54 when the input relay circuit 52 is not turned on.

The multiple short circuits 44 are provided for each of the M battery management devices 22 in correspondence with the multiple monitor terminals 34 excluding the lowest-ranked monitor terminal 34. Each of the multiple short circuits 44 shorts or opens the corresponding monitor terminal 34 for each of the M battery management devices 22 with the monitor terminal 34 one rank lower than the corresponding monitor terminal 34. When the control device 26 detects the voltage of the battery cell 30 by the corresponding monitor terminal 34, it turns off the corresponding short circuit 44, and when the control device 26 does not detect the voltage of the battery cell 30 by the corresponding monitor terminal 34, it turns on the corresponding short circuit 44.

3 shows an example in which each of the N switch circuits 42 includes one input relay circuit 52. However, each of the N switch circuits 42 may include N input relay circuits 52 that correspond one-to-one to the N holders 32 of the battery pack 20. In this case, each of the N switch circuits 42 is associated with one of the N holders 32, and one of the N input relay circuits 52 connected to the corresponding holder 32 is turned on, and the other input relay circuits 52 are turned off.

Figure 4 is a flowchart showing the processing flow of the control device 26. For example, at startup, the control device 26 executes the processing flow shown in Figure 4. Note that the control device 26 may execute the processing flow shown in Figure 4 at the first startup after some of the battery cells 30 included in the battery pack 20 have been removed, replaced, or added.

First, in S11, the control device 26 detects a plurality of valid holders that hold battery cells 30 out of the N holders 32 included in the battery pack 20. This allows the control device 26 to detect the number of battery cells 30 that are held in the battery pack 20 and the positions of the holders 32 that hold the battery cells 30.

Next, in S12, the control device 26 divides the multiple battery cells 30 included in the battery pack 20 into one or more cell units each of which is connected in series. Then, the control device 26 associates each of the one or more cell units with one of the M battery management devices 22.

In this case, the control device 26 sets each of the one or more cell units so that they can be connected to the corresponding battery management device 22 according to a predetermined connection rule. For example, the control device 26 sets each of the one or more cell units so that each of the multiple battery cells 30 included in the battery pack 20 is included in one of the cell units. The control device 26 also sets each of the one or more cell units so that they become part of the multiple battery cells 30 included in the battery pack 20 that are connected in series. Furthermore, the connection device 24 sets each of the one or more cell units so that they generate a voltage equal to or higher than the minimum input voltage to be applied to the corresponding battery management device 22 and the number of battery cells 30 included is equal to or lower than the maximum number that can be connected to the corresponding battery management device 22.

For example, the control device 26 may set each of one or more cell units so that the number of battery cells 30 included therein is the same as or differs by one from the other cell units. This allows the control device 26 to roughly equalize the processing load of each of the M battery management devices 22.

The control device 26 may prestore a table describing how to set one or more cell units for each number of battery cells 30. The control device 26 may then set one or more cell units based on the number of valid holders and the table.

Next, in S13, the control device 26 determines, for each of one or more cell units, which of the multiple monitor terminals 34 of the corresponding battery management device 22 each of the multiple battery cells 30 included therein should be connected to, according to a connection rule. For example, the control device 26 determines, for each of the M battery management devices 22, which of the multiple monitor terminals 34 each of the multiple battery cells 30 included therein should be connected to, so that voltages are applied to the multiple monitor terminals 34 in ascending order according to their ranks.

Each of the M battery management devices 22 may have a multiplexer or the like inside, and may sequentially select monitor terminals 34 using the multiplexer to detect the voltages of the battery cells 30. In such a case, when fewer than the maximum number of battery cells 30 that can be connected are connected to each of the M battery management devices 22, the monitor terminal 34 selected first by the multiplexer completes voltage detection at an earlier timing than the monitor terminal 34 selected later. Therefore, the control device 26 may determine to which of the multiple monitor terminals 34 each of the multiple battery cells 30 included in each of the M battery management devices 22 is to be connected so as to detect the state of two or more battery cells 30 included in the corresponding cell unit in the shortest time.

Next, in S14, the control device 26 controls the connection device 24 to switch so that each of the multiple battery cells 30 included in the battery pack 20 is connected to the determined monitor terminal 34. For example, the control device 26 switches the connections of the input relay circuit 52 and the multiple output relay circuits 54 included in each of the N switch circuits 42, as well as the multiple short circuits 44. Then, when the control device 26 finishes the processing of S14, it ends this flow.

Specific connection examples are explained below.

Figure 5 is a diagram showing a first connection example using the connection device 24. In the first connection example, the battery management system 10 includes a first battery management device 22-1 and a second battery management device 22-2, and the battery pack 20 includes eight holders 32 from the first holder 32 to the eighth holder 32. Each of the first battery management device 22-1 and the second battery management device 22-2 has five monitor terminals 34 (In0 to In4) and can manage four battery cells 30.

In the first connection example shown in FIG. 5, the fifth holder 32 and the eighth holder 32 do not hold a battery cell 30. In addition, the connection device 24 connects the first holder 32 between the monitor terminals In0 and In1 of the first battery management device 22-1, the second holder 32 between the monitor terminals In1 and In2 of the first battery management device 22-1, the third holder 32 between the monitor terminals In2 and In3 of the first battery management device 22-1, and the fourth holder 32 between the monitor terminals In3 and In4 of the first battery management device 22-1.

The connection device 24 also connects the sixth holder 32 between the monitor terminals In0 and In1 of the second battery management unit 22-2, and connects the seventh holder 32 between the monitor terminals In1 and In2 of the second battery management unit 22-2. Furthermore, the connection device 24 shorts between the monitor terminals In2 and In3 of the second battery management unit 22-2, and between the monitor terminals In3 and In4 of the second battery management unit 22-2.

By connecting in this manner, the first battery management unit 22-1 and the second battery management unit 22-2 can manage the state of each battery cell 30 even when the fifth holder 32 and the eighth holder 32 are not holding a battery cell 30.

Figure 6 is a diagram showing a second connection example using the connection device 24. In the second connection example, the battery management system 10 includes a first battery management device 22-1 and a second battery management device 22-2, and the battery pack 20 includes 16 holders 32 from the first holder 32 to the 16th holder 32. Each of the first battery management device 22-1 and the second battery management device 22-2 has nine monitor terminals 34 (In0 to In8) and can manage eight battery cells 30.

In the second connection example shown in FIG. 6, the fifth to eighth holders 32, the twelfth holder 32, and the fourteenth to sixteenth holders 32 do not hold battery cells 30. In addition, the connection device 24 connects the first holder 32 between the monitor terminals In0 and In1 of the first battery management device 22-1, the second holder 32 between the monitor terminals In1 and In2 of the first battery management device 22-1, the third holder 32 between the monitor terminals In4 and In5 of the first battery management device 22-1, and the fourth holder 32 between the monitor terminals In5 and In6 of the first battery management device 22-1.

The connection device 24 also connects the ninth holder 32 between the monitor terminals In0 and In1 of the second battery management device 22-2, the tenth holder 32 between the monitor terminals In1 and In2 of the second battery management device 22-2, the eleventh holder 32 between the monitor terminals In4 and In5 of the second battery management device 22-2, and the thirteenth holder 32 between the monitor terminals In5 and In6 of the second battery management device 22-2.

The connection device 24 also shorts between the monitor terminals 34 of In2 and In3, between the monitor terminals 34 of In3 and In4, between the monitor terminals 34 of In6 and In7, and between the monitor terminals 34 of In7 and In8 of the first battery management unit 22-1. The connection device 24 also shorts between the monitor terminals 34 of In2 and In3, between the monitor terminals 34 of In3 and In4, between the monitor terminals 34 of In6 and In7, and between the monitor terminals 34 of In7 and In8 of the second battery management unit 22-2.

By connecting in this manner, the first battery management unit 22-1 and the second battery management unit 22-2 can manage the state of each battery cell 30 even when the fifth through eighth holders 32, the twelfth holder 32, and the fourteenth through sixteenth holders 32 are not holding a battery cell 30.

Figure 7 is a diagram showing a third connection example using the connection device 24. In the third connection example, the battery management system 10 includes a first battery management device 22-1 and a second battery management device 22-2, and the battery pack 20 includes 16 holders 32 from the first holder 32 to the 16th holder 32. Each of the first battery management device 22-1 and the second battery management device 22-2 has nine monitor terminals 34 (In0 to In8) and can manage eight battery cells 30.

In the third connection example shown in FIG. 7, the 9th to 16th holders 32 do not hold battery cells 30. In addition, the connection device 24 connects the first holder 32 between the monitor terminals In0 and In1 of the first battery management device 22-1, the second holder 32 between the monitor terminals In1 and In2 of the first battery management device 22-1, the third holder 32 between the monitor terminals In4 and In5 of the first battery management device 22-1, and the fourth holder 32 between the monitor terminals In5 and In6 of the first battery management device 22-1.

The connection device 24 also connects the fifth holder 32 between the monitor terminals In0 and In1 of the second battery management device 22-2, the sixth holder 32 between the monitor terminals In1 and In2 of the second battery management device 22-2, the seventh holder 32 between the monitor terminals In4 and In5 of the second battery management device 22-2, and the eighth holder 32 between the monitor terminals In5 and In6 of the second battery management device 22-2.

The connection device 24 also shorts between the monitor terminals 34 of In2 and In3, between the monitor terminals 34 of In3 and In4, between the monitor terminals 34 of In6 and In7, and between the monitor terminals 34 of In7 and In8 of the first battery management unit 22-1. The connection device 24 also shorts between the monitor terminals 34 of In2 and In3, between the monitor terminals 34 of In3 and In4, between the monitor terminals 34 of In6 and In7, and between the monitor terminals 34 of In7 and In8 of the second battery management unit 22-2.

By connecting in this manner, the first battery management unit 22-1 and the second battery management unit 22-2 can manage the state of each battery cell 30 even when the 9th to 16th holders 32 are not holding a battery cell 30.

In the battery management system 10 according to the present embodiment as described above, when some of the battery cells 30 included in the battery pack 20 are removed, replaced, or added, the connection device 24 switches between the battery pack 20 and each of the M battery management devices 22 according to a predetermined connection rule. As a result, the battery management system 10 according to the present embodiment can easily and accurately connect the battery pack 20 and each of the M battery management devices 22.

Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. Various modifications can be made to the embodiments.

10 Battery management system, 20 Battery pack, 22 Battery management device, 24 Connection device, 26 Control device, 30 Battery cell, 32 Holder, 34 Monitor terminal, 42 Switch circuit, 44 Short circuit, 52 Input relay circuit, 54 Output relay circuit

Claims (3)

a battery pack including N holders (N is an integer of 2 or more) each for detachably holding a battery cell, the battery pack connecting the battery cells held by the N holders in series;
M battery management devices (M is an integer equal to or greater than 1) each connected to a cell unit, the cell unit being a set of two or more battery cells connected in series, for managing the state of each battery cell included in the cell unit;
a connection device that is capable of switching and connecting the battery cells held by each of the N holders to any one of the M battery management devices;
a control device that detects a plurality of valid holders that hold battery cells among the N holders, and switches and controls the connection device based on positions of the plurality of valid holders so that the cell unit is connected to any one of the M battery management devices in accordance with a predetermined connection rule;
A battery management system comprising: Each of the M battery management units has a plurality of monitor terminals to which battery cells are connected;
the connection device has N switch circuits that correspond one-to-one to the N holders,
Each of the N switch circuits is capable of switching and connecting a target battery cell held by a corresponding holder to any one of the plurality of monitor terminals of each of the M battery management devices,
The control device includes:
Dividing the battery cells into one or more cell units, each of which corresponds to one of the M battery management units, based on the positions of the effective holders;
2. The battery management system according to claim 1, further comprising: a switching control circuit for switching each of the N switch circuits so as to connect the target battery cell to any one of the plurality of monitor terminals of the corresponding battery management device in accordance with the connection rule. Each of the one or more cell units is
3. The battery management system according to claim 2, wherein the battery management system generates a voltage equal to or higher than a minimum input voltage to be applied to the corresponding battery management unit, and includes a number of the battery cells equal to or lower than a maximum number connectable to the corresponding battery management unit.

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