Battery Management System

Abstract

To achieve simple and accurate connection.SOLUTION: A battery management system comprises a battery pack, M battery management devices, a connection device, and a control device. The battery pack has N holders that hold battery cells freely attachably / detachably, and in which a plurality of battery cells held by the N holders is connected in series. The battery management device is connected with a cell unit that is a set of two or more series-connected battery cells to manage a state of each battery cell included in the cell unit. The connection device can switch and connect the battery cell held by each of the N holders to any one of the M battery management devices. The control device detects a plurality of available holders, performs switching control of the connection device on the basis of positions of the plurality of available holders so that the cell unit is connected to any one of the M battery management devices according to a preliminarily set connection rule.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a battery management system.

Background Art

[0002] For example, a battery pack used in an electric vehicle is known. The battery pack includes a plurality of 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 a plurality of monitor terminals, and each battery cell included in the battery pack is connected to each monitor terminal.

[0003] Patent Document 1 describes a battery pack that is booted 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 including a cell controller that detects the state of battery cells constituting a battery block and eliminates the imbalance in the charge state 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 battery packs in a battery system in which a plurality of battery packs obtained by connecting a plurality of unit batteries in series are connected in parallel.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Patent Document 3

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, when a part of the battery cells included in the battery pack is removed or newly attached, it is necessary to re-wire appropriately between the monitor terminals of the battery management LSI and each battery cell included in the battery pack. The battery management LSI has specifications such as the maximum number of connectable battery cells and the minimum voltage to be applied defined in advance. Therefore, when a part of the battery cells included in the battery pack is removed or newly attached, the wiring between the monitor terminals of the battery management LSI and each battery cell included in the battery pack must be re-wired according to the specifications, which makes the work complicated. Also, depending on the environment where the battery management LSI and the battery pack are arranged, there is a possibility of connection errors.

[0006] The present invention has been made in view of the above, and an object thereof is to provide a battery management system capable of easily and accurately connecting between a battery pack and a battery management device.

Means for Solving the Problems

[0007] In order to solve the above-described problems and achieve the object, a battery management system according to the present invention has N holders (N is an integer of 2 or more) each of which detachably holds a battery cell, and a battery pack that connects a plurality of battery cells held by the N holders in series, and M battery management devices (M is an integer of 1 or more) each of which is connected to a cell unit that is a set of 2 or more battery cells connected in series and manages the state of each battery cell included in the cell unit, and a connection device capable of switching and connecting the battery cells held by each of the N holders to any one of the M battery management devices, and a control device that detects a plurality of effective holders that hold battery cells among the N holders and switches and controls the connection device based on the positions of the plurality of effective holders so that the cell unit is connected to any one of the M battery management devices according to a predetermined connection rule.

Effects of the Invention

[0008] According to the present invention, the connection between the battery pack and the battery management device can be easily and accurately made.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0010] Hereinafter, embodiments will be described with reference to the drawings.

[0011] FIG. 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 or the like. The battery management system 10 may supply power not only to a vehicle but also to other devices.

[0012] The battery management system 10 includes a battery pack 20, M (M is an integer of 1 or more) battery management devices 22, a connection device 24, and a control device 26.

[0013] The battery pack 20 includes a plurality of battery cells 30 connected in series and generates direct current power. For example, the battery pack 20 generates power for driving a motor of a vehicle. Each of the plurality of battery cells 30 is a secondary battery.

[0014] The battery pack 20 has N holders 32 (N is an integer of 2 or more). Each of the N holders 32 detachably holds the battery cell 30.

[0015] The battery pack 20 connects in series a plurality of battery cells 30 held by the N holders 32. Note that a part of the N holders 32 may be in a state of not holding the battery cell 30. When each of the N holders 32 does not hold the battery cell 30, it shorts between the contact where the plus terminal of the battery cell 30 contacts and the contact where the minus terminal of the battery cell 30 contacts. Thereby, even when the battery cell 30 is not attached to a part of the N holders 32, the battery pack 20 can connect in series a plurality of battery cells 30 having a number less than N held by the N holders 32.

[0016] Such a battery pack 20 can remove a part of the plurality of battery cells 30, replace a part of the plurality of battery cells 30, or add a new battery cell 30 to the plurality of battery cells 30. Thereby, when a part of the plurality of battery cells 30 deteriorates or fails, etc., the battery pack 20 does not need to replace all of the plurality of battery cells 30 it holds, so the battery cells 30 can be used efficiently.

[0017] Each of the M battery management devices 22 is connected to a cell unit that is a set of two or more battery cells 30. The cell unit is a part of the plurality of 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 plurality of 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 plurality of battery cells 30 held by the battery pack 20.

[0018] Each cell unit is associated with any one of the M battery management devices 22. Each of the M battery management devices 22 has a corresponding cell unit connected 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. Further, each of the M battery management devices 22 performs cell balance control so that the charge states of the battery cells 30 included in the connected cell unit are uniform.

[0019] 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.

[0020] Furthermore, each of the M battery management devices 22 has a plurality of monitor terminals 34 to which the battery cells 30 are connected. Each of the M battery management devices 22 has a battery cell 30 connected to each of the plurality of monitor terminals 34 according to a predetermined connection rule. An example of the connection rule will be described later with reference to FIG. 2.

[0021] 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 one 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 and each of the plurality of monitor terminals 34 of the M battery management devices 22 in an arbitrary combination. That is, the connection device 24 can connect each of the plurality of battery cells 30 held by the N holders 32 to any one of the plurality of monitor terminals 34 of each of the M battery management devices 22. Note that 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.

[0022] When a part of the plurality of battery cells 30 included in the battery pack 20 is removed, a part of the plurality of battery cells 30 is replaced, or a new battery cell 30 is added to the plurality of battery cells 30, the control device 26 performs switching control on the connection state of the connection device 24. Further, when a predetermined event occurs, for example, at startup, the control device 26 may perform switching control on the connection state of the connection device 24.

[0023] When performing switching control on the connection state of the connection device 24, the control device 26 detects a plurality of valid holders that hold the battery cells 30 among the N holders 32 included in the battery pack 20. For example, the control device 26 may detect a valid holder that holds the battery cell 30 by detecting the voltage of each of the N holders 32 included in the battery pack 20.

[0024] Subsequently, the control device 26 switches and controls the connection device 24 based on the positions of the detected plurality of valid holders so that each cell unit is connected according to a predetermined connection rule to any one of the M battery management devices 22. More specifically, the control device 26 divides the plurality of 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 plurality of valid holders. Subsequently, the control device 26 associates each of the one or more cell units with any one of the M battery management devices 22. Then, the control device 26 switches and controls the connection device 24 so that each of the plurality of battery cells 30 is connected to any one of the plurality of monitor terminals 34 of the corresponding battery management device 22 according to the connection rule.

[0025] Thereby, the M battery management devices 22 can appropriately manage the states of each of the plurality of battery cells 30 included in the battery pack 20.

[0026] FIG. 2 is a diagram for explaining an example of the connection rule of the M battery management devices 22. For example, each of the M battery management devices 22 has a maximum number of connectable battery cells 30 defined as one of the connection rules. Therefore, each of the one or more cell units is set so that the number of included battery cells 30 is equal to or less than the maximum number connectable to the corresponding battery management device 22. For example, in the example of FIG. 2, the maximum number of battery cells 30 connectable to the battery management device 22 is four. Note that the maximum number of battery cells 30 connectable to the battery management device 22 is not limited to four and may be other numbers.

[0027] Also, as an example, each of the M battery management devices 22 has a minimum input voltage to be applied defined as one of the connection rules. Therefore, each of the one or more cell units is set so that the generated voltage is equal to or higher than the minimum input voltage to be applied to the corresponding battery management device 22.

[0028] Also, as an example, the plurality of monitor terminals 34 each included in the M battery management devices 22 are ranked in ascending order according to the magnitude of the applied voltage. And each of the M battery management devices 22 is defined, as a connection rule, such that voltages are applied in ascending order according to the rank to each of the plurality of monitor terminals 34. Also, as an example, each of the M battery management devices 22 is defined, as a connection rule, such that some voltage is applied to each of the plurality of monitor terminals 34. Also, as an example, it is defined that the same voltage may be applied to two or more monitor terminals 34 having adjacent ranks. Therefore, when following such a connection rule, the connection device 24 switches such that voltages are applied in ascending order according to the rank to each of the plurality of monitor terminals 34 for each of the M battery management devices 22 and some voltage is applied.

[0029] For example, each of the plurality of monitor terminals 34 is connected to either the negative terminal of the battery cell 30 arranged 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 rank (In0) among the five monitor terminals 34 is connected to the negative terminal of the battery cell 30 arranged on the most negative side in the cell unit to be connected.

[0030] Also, each of the plurality of monitor terminals 34 with ranks (In1, In2, In3, In4) other than the lowest rank among the five monitor terminals 34 is connected to the positive terminal of each battery cell 30 in the cell unit to be connected. Also, 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 arranged on the most positive side in the cell unit to be connected.

[0031] In such an example of FIG. 2, when following the above-described connection rules, the connection device 24 connects the negative terminal and the positive terminal of one battery cell 30 between two monitor terminals 34 of adjacent ranks. Also, when 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 adjacent-rank monitor terminals 34.

[0032] Also, the M battery management devices 22 cooperate with each other to manage the states of two or more cell units connected in series. In this case, the monitor terminal 34 with the highest rank (In4) of the battery management device 22 arranged on the low-potential side among two adjacent battery management devices 22 is connected to the monitor terminal 34 with the lowest rank (In0) of the battery management device 22 arranged on the high-potential side.

[0033] FIG. 3 is a diagram showing an example of the configuration of the connection device 24 together with the battery pack 20 and the battery management device 22. The connection device 24 has, as an example, N switch circuits 42 and a plurality of short-circuit 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 be switched and connected to any one of the plurality of monitor terminals 34 each of the M battery management devices 22 has for the target battery cell 30 held by the corresponding holder 32.

[0034] For example, each of the N switch circuits 42 includes an input relay circuit 52 and a plurality of output relay circuits 54.

[0035] The input relay circuit 52 switches whether to connect the target battery cell 30 to any of the M battery management devices 22. For example, when the battery cell 30 is not held in the corresponding holder 32, 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. Also, when the battery cell 30 is held in the corresponding holder 32, 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.

[0036] In the present 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 plus terminal of the target battery cell 30. The second input terminal 64 is connected to the minus 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 with synchronous on / off. 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.

[0037] Each of the N switch circuits 42 includes output relay circuits 54 in number corresponding to the number of battery cells 30 that can be managed by the M battery management devices 22 as a plurality of output relay circuits 54. Each of the plurality of output relay circuits 54 corresponds to a monitor terminal 34 of any one of the M battery management devices 22. That is, the plurality of output relay circuits 54 are provided corresponding to all the monitor terminals 34 of the M battery management devices 22. And each of the plurality of output relay circuits 54 switches whether to connect the input relay circuit 52 to the corresponding monitor terminal 34.

[0038] In this embodiment, the plurality of output relay circuits 54 are provided corresponding to a plurality of monitor terminals 34 excluding the lowest-ranked monitor terminal 34 for each of the M battery management devices 22. Also, in this embodiment, each of the plurality of 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.

[0039] 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 with a rank one lower than that of 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 with synchronized on / off.

[0040] When the control device 26 causes the voltage of the battery cell 30 to be detected by the corresponding monitor terminal 34, the third switch 92 and the fourth switch 94 are turned on. When the control device 26 does not cause the voltage of the battery cell 30 to be detected by the corresponding monitor terminal 34, the third switch 92 and the fourth switch 94 are turned off. Note that the control device 26 turns on only one of the plurality of output relay circuits 54 and turns off the other output relay circuits 54 for each of the N switch circuits 42. Also, the control device 26 may turn off all the output relay circuits 54 when the input relay circuit 52 is not on.

[0041] A plurality of short - circuit circuits 44 are provided corresponding to a plurality of monitor terminals 34 excluding the lowest - ranked monitor terminal 34 for each of the M battery management devices 22. Each of the plurality of short - circuit circuits 44 shorts or opens between the corresponding monitor terminal 34 and the monitor terminal 34 with a rank one lower than the corresponding monitor terminal 34 for each of the M battery management devices 22. When the control device 26 detects the voltage of the battery cell 30 by the corresponding monitor terminal 34, the corresponding short - circuit circuit 44 is turned off, and when the control device 26 does not detect the voltage of the battery cell 30 by the corresponding monitor terminal 34, the corresponding short - circuit circuit 44 is turned on.

[0042] In the example of FIG. 3, an example in which each of the N switch circuits 42 includes one input relay circuit 52 is shown. 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 input relay circuit 52 connected to the corresponding holder 32 among the N input relay circuits 52 is turned on, and the other input relay circuits 52 are turned off.

[0043] FIG. 4 is a flowchart showing the flow of processing of the control device 26. For example, at startup, the control device 26 executes processing in the flow shown in FIG. 4. Note that the control device 26 may execute processing in the flow shown in FIG. 4 at the first startup after a part of the plurality of battery cells 30 included in the battery pack 20 is removed, replaced, or added.

[0044] First, in S11, the control device 26 detects a plurality of valid holders that hold the battery cells 30 among the N holders 32 included in the battery pack 20. Thereby, the control device 26 can detect the number of the plurality of battery cells 30 held by the battery pack 20 and the positions of the holders 32 that hold the battery cells 30.

[0045] Subsequently, in S12, the control device 26 divides the plurality of 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 any one of the M battery management devices 22.

[0046] In this case, the control device 26 sets each of the one or more cell units so that it 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 such that each of the plurality of battery cells 30 included in the battery pack 20 is included in any one cell unit. Also, the control device 26 sets each of the one or more cell units such that it forms a part of the series connection of the plurality of battery cells 30 included in the battery pack 20. Further, the connection device 24 generates a voltage equal to or higher than the minimum input voltage to be applied to the corresponding battery management device 22, and sets each of the one or more cell units such that the number of included battery cells 30 is equal to or less than the maximum number connectable to the corresponding battery management device 22.

[0047] Also, for example, the control device 26 may set each of the one or more cell units such that the number of included battery cells 30 is the same as or one different from the number of other cell units. Thereby, the control device 26 can make the processing load of each of the M battery management devices 22 substantially equal.

[0048] Note that the control device 26 may store in advance a table describing how to set one or more cell units for each number of battery cells 30. Then, the control device 26 may set one or more cell units based on the number of valid holders and the table.

[0049] Subsequently, in S13, for each of the one or more cell units, the control device 26 determines, according to the connection rule, to which of the plurality of monitor terminals 34 included in the corresponding battery management device 22 each of the plurality of battery cells 30 is to be connected. For example, for each of the M battery management devices 22, the control device 26 determines to which of the plurality of monitor terminals 34 each of the plurality of battery cells 30 is to be connected so that voltages are applied in ascending order according to the ranking to each of the plurality of monitor terminals 34.

[0050] Note that each of the M battery management devices 22 may have a multiplexer or the like inside, and in some cases, the multiplexer sequentially selects the monitor terminals 34 to detect the voltage or the like of the battery cell 30. In such a case, when a number of battery cells 30 less than the maximum connectable number are connected to each of the M battery management devices 22, the monitor terminal 34 selected earlier by the multiplexer completes voltage detection at an earlier timing than the monitor terminal 34 selected later. Therefore, the control device 26 may determine, for each of the M battery management devices 22, to which of the plurality of monitor terminals 34 each of the plurality of battery cells 30 is to be connected so as to detect the states of two or more battery cells 30 included in the corresponding cell unit in the shortest time.

[0051] Subsequently, in S14, the control device 26 controls the switching of the connection device 24 so as to connect each of the plurality of battery cells 30 included in the battery pack 20 to the determined monitor terminal 34. For example, the control device 26 switches the connection of the input relay circuit 52 and the plurality of output relay circuits 54 included in each of the N switch circuits 42, and the plurality of short - circuit circuits 44. Then, when the process of S14 is completed, the control device 26 ends this flow.

[0052] Hereinafter, a specific connection example will be described.

[0053] FIG. 5 is a diagram showing a first connection example by the connection device 24. The first connection example is a configuration in which 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 has 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.

[0054] In the first connection example shown in FIG. 5, the fifth holder 32 and the eighth holder 32 do not hold the battery cell 30. Also, the connection device 24 connects the first holder 32 between the In0 and In1 monitor terminals 34 of the first battery management device 22-1, connects the second holder 32 between the In1 and In2 monitor terminals 34 of the first battery management device 22-1, connects the third holder 32 between the In2 and In3 monitor terminals 34 of the first battery management device 22-1, and connects the fourth holder 32 between the In3 and In4 monitor terminals 34 of the first battery management device 22-1.

[0055] Also, the connection device 24 connects the sixth holder 32 between the In0 and In1 monitor terminals 34 of the second battery management device 22-2, and connects the seventh holder 32 between the In1 and In2 monitor terminals 34 of the second battery management device 22-2. Further, the connection device 24 shorts between the In2 and In3 monitor terminals 34 and between the In3 and In4 monitor terminals 34 of the second battery management device 22-2.

[0056] By connecting in this way, the first battery management device 22-1 and the second battery management device 22-2 can manage the state of each battery cell 30 even when the fifth holder 32 and the eighth holder 32 do not hold the battery cell 30.

[0057] FIG. 6 is a diagram showing a second connection example by the connection device 24. The second connection example is a configuration in which 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 has 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.

[0058] In the second connection example shown in FIG. 6, the 5th to 8th holders 32, the 12th holder 32, and the 14th to 16th holders 32 do not hold the battery cells 30. Also, the connection device 24 connects the first holder 32 between the monitor terminals 34 of In0 and In1 of the first battery management device 22-1, connects the second holder 32 between the monitor terminals 34 of In1 and In2 of the first battery management device 22-1, connects the third holder 32 between the monitor terminals 34 of In4 and In5 of the first battery management device 22-1, and connects the fourth holder 32 between the monitor terminals 34 of In5 and In6 of the first battery management device 22-1.

[0059] Also, the connection device 24 connects the ninth holder 32 between the monitor terminals 34 of In0 and In1 of the second battery management device 22-2, connects the tenth holder 32 between the monitor terminals 34 of In1 and In2 of the second battery management device 22-2, connects the eleventh holder 32 between the monitor terminals 34 of In4 and In5 of the second battery management device 22-2, and connects the thirteenth holder 32 between the monitor terminals 34 of In5 and In6 of the second battery management device 22-2.

[0060] Furthermore, the connection device 24 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 device 22-1. Also, the connection device 24 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 device 22-2.

[0061] By connecting in this way, the first battery management device 22-1 and the second battery management device 22-2 can manage the state of each battery cell 30 even when the 5th to 8th holders 32, the 12th holder 32, and the 14th to 16th holders 32 do not hold the battery cells 30.

[0062] FIG. 7 is a diagram showing a third connection example by the connection device 24. The third connection example is a configuration in which the battery management system 10 includes the first battery management device 22-1 and the second battery management device 22-2, and the battery pack 20 has 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 9 monitor terminals 34 (In0 to In8) and can manage 8 battery cells 30.

[0063] In the third connection example shown in FIG. 7, the 9th to 16th holders 32 do not hold the battery cells 30. Also, the connection device 24 connects the first holder 32 between the monitor terminals 34 of In0 and In1 of the first battery management device 22-1, connects the second holder 32 between the monitor terminals 34 of In1 and In2 of the first battery management device 22-1, connects the third holder 32 between the monitor terminals 34 of In4 and In5 of the first battery management device 22-1, and connects the fourth holder 32 between the monitor terminals 34 of In5 and In6 of the first battery management device 22-1.

[0064] Further, the connection device 24 connects the fifth holder 32 between the In0 and In1 monitor terminals 34 of the second battery management device 22-2, connects the sixth holder 32 between the In1 and In2 monitor terminals 34 of the second battery management device 22-2, connects the seventh holder 32 between the In4 and In5 monitor terminals 34 of the second battery management device 22-2, and connects the eighth holder 32 between the In5 and In6 monitor terminals 34 of the second battery management device 22-2.

[0065] Furthermore, the connection device 24 shorts between the In2 and In3 monitor terminals 34, between the In3 and In4 monitor terminals 34, between the In6 and In7 monitor terminals 34, and between the In7 and In8 monitor terminals 34 of the first battery management device 22-1. Also, the connection device 24 shorts between the In2 and In3 monitor terminals 34, between the In3 and In4 monitor terminals 34, between the In6 and In7 monitor terminals 34, and between the In7 and In8 monitor terminals 34 of the second battery management device 22-2.

[0066] By connecting in this way, the first battery management device 22-1 and the second battery management device 22-2 can manage the state of each battery cell 30 even when the ninth to sixteenth holders 32 do not hold the battery cells 30.

[0067] As described above, in the battery management system 10 according to the present embodiment, when some of the plurality of 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. Thereby, according to the battery management system 10 according to the present embodiment, the connection between the battery pack 20 and each of the M battery management devices 22 can be easily and accurately made.

[0068] As described above, the embodiments of the present invention have been explained. However, these embodiments are presented as examples and are not intended to limit the scope of the invention. The embodiments can be modified in various ways.

Description of Reference Numerals

[0069] 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 circuit, 52 Input relay circuit, 54 Output relay circuit

Claims

1. A battery pack having N holders (N is an integer of 2 or more) each detachably holding a battery cell, and connecting in series a plurality of battery cells held by the N holders; M battery management devices (M is an integer of 1 or more), each having a cell unit which is a set of two or more battery cells connected in series, and managing the state of each battery cell included in the cell unit; A connection device capable of switching and connecting the battery cell 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 holding 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 any one of the M battery management devices according to a predetermined connection rule; A battery management system comprising the above.

2. Each of the M battery management devices has a plurality of monitor terminals to which a battery cell is connected; The connection device has N switch circuits corresponding one-to-one to the N holders; Each of the N switch circuits can switch and connect the target battery cell held by the corresponding holder to any one of the plurality of monitor terminals each of the M battery management devices has; The control device: Based on the positions of the plurality of valid holders, divides the plurality of battery cells into one or more cell units each corresponding to any one of the M battery management devices; For each of the N switch circuits, performs switching control so that the target battery cell is connected to any one of the plurality of monitor terminals of the corresponding battery management device according to the connection rule. The battery management system according to Claim 1.

3. Each of the one or more cell units: Generates a voltage equal to or higher than the minimum input voltage to be applied to the corresponding battery management device, and the number of battery cells included is equal to or less than the maximum number connectable to the corresponding battery management device. The battery management system according to Claim 2.

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