Battery management device and method for managing a battery device

Abstract

A battery management device that manages a battery pack in which a plurality of batteries are connected in series includes a control unit, an activation switch, and a power supply activation circuit that turns on the activation switch when an external activation signal is in an activation logic and maintains the activation switch on as long as an activation maintenance signal is being input. The control unit includes a line switch control unit, an activation maintenance control unit, and an OCV determination unit. If the external activation signal is in the activation logic, the line switch control unit turns on a line switch. When the external activation signal is in the activation logic, the activation maintenance control unit starts outputting the activation maintenance signal to the power supply activation circuit. When the external activation signal is in a stop logic, the OCV determination unit acquires a voltage change amount of each battery at a prescribed time interval, and when the voltage change amounts are all below a prescribed change amount, the OCV determination unit records the voltage of each battery as an OCV and stops outputting the activation maintenance signal.

Description

Technical Field

[0001] The technology disclosed in this specification relates to battery management devices and methods for managing battery devices. Background Technology

[0002] In a battery pack consisting of multiple batteries connected in series, for example, to estimate the SOC (State of Charge) of each battery, the OCV (Open Circuit Voltage) of each battery needs to be measured.

[0003] The battery voltage varies depending on the operating state of the device that operates via the battery. Therefore, techniques are known to obtain accurate battery voltage measurements by measuring the battery voltage when the device is in a specific operating mode (e.g., see Patent Document 1). Furthermore, techniques are known to repeatedly measure the battery voltage at predetermined intervals, since the battery voltage may vary even when the device is in a specific operating mode, and calculate the average of these measurements as the battery voltage (e.g., see Patent Document 2).

[0004] Prior art literature

[0005] Patent documents

[0006] Patent Document 1: Japanese Patent Application Publication No. 6-224844

[0007] Patent Document 2: Japanese Patent Application Publication No. 10-229646 Summary of the Invention

[0008] The problem that the invention aims to solve

[0009] When measuring the OCV of each battery constituting the battery pack using the conventional technology described above, the control unit that performs the OCV measurement is in the OCV measurement state (or measurement standby state) for a long time, thus posing a problem of high power consumption required for OCV measurement.

[0010] This specification discloses a technique that can solve the above-mentioned problems.

[0011] Methods for solving problems

[0012] The techniques disclosed in this specification can be implemented, for example, in the following ways.

[0013] (1) The first battery management device disclosed in this specification is a device for managing a battery pack consisting of multiple batteries connected in series, and includes a voltage measuring unit, a control unit, a voltage conversion circuit, a start switch, and a power start circuit. The voltage measuring unit measures the voltage of each of the multiple batteries. The voltage conversion circuit is provided on the path from the battery pack to the control unit. The start switch is connected between the voltage conversion circuit and the battery pack. The power start circuit has an input terminal for receiving an external start signal. When the external start signal becomes a start logic, the power start circuit turns the start switch on and outputs a monitoring signal indicating the logic state of the external start signal to the control unit. The power start circuit maintains the on state of the start switch as long as a start sustain signal is being input from the control unit. In addition, the control unit includes a line switch control unit, a start sustain control unit, and an OCV determination unit. When the logic state of the external start signal becomes start, the line switch control unit turns on the line switch connected in series with the battery pack. When the logic state of the external start signal becomes stop, the line switch control unit turns off the line switch. When the logic state of the external start signal becomes start, the start-up sustain control unit starts outputting the start-up sustain signal to the power start-up circuit. When the logic state of the external start signal becomes stop, the OCV determination unit acquires the voltage change of each of the plurality of batteries measured by the voltage measuring unit at predetermined time intervals. When the voltage change of each of the plurality of batteries is all below a predetermined change, the voltage of each of the plurality of batteries at that moment is recorded as OCV, and the start-up sustain control unit stops outputting the start-up sustain signal.

[0014] According to this battery management device, after the logic state of the external start signal becomes the stop logic and the line switch becomes the open state, if the voltage change of each battery is all below a predetermined change, that is, if the voltage of each battery sufficiently converges, the voltage at that moment is recorded as OCV, thus enabling high-precision determination of the OCV of each battery. Furthermore, it enables high-precision execution of predetermined processes using OCV (e.g., SOC estimation). In addition, according to this battery management device, if the OCV is recorded, the output of the start sustain signal is immediately stopped, the start switch becomes the open state, and the power supply from the battery pack to the control unit is stopped, thus reducing the power consumption required to determine the OCV of each battery.

[0015] (2) In the above-described battery management device, the OCV determination unit may also be configured such that, when the logic state of the external start signal becomes the stop logic, it acquires the voltage change of each of the plurality of batteries measured by the voltage measurement unit at predetermined time intervals. Before the voltage change of each of the plurality of batteries falls below a predetermined value, each time the number of acquisitions of the change value reaches a predetermined number, it estimates the OCV of each of the plurality of batteries based on the acquired change value and records them. According to this battery management device, the OCV of each battery can be determined at a relatively early time. Furthermore, the predetermined processing using OCV (e.g., SOC estimation) can be performed at a relatively early time. In addition, according to this battery management device, even if the logic state of the external start signal becomes the start logic before the voltage change of each battery falls below the predetermined value, and the circuit switch becomes the on state, making it impossible to measure the OCV of each battery, the previously performed OCV estimation results can still be used to determine the OCV of each battery. Furthermore, it is possible to avoid situations where prescribed processes (e.g., SOC estimation) cannot be performed using OCV.

[0016] (3) The second battery management device disclosed in this specification is a device for managing a battery pack consisting of multiple batteries connected in series. It includes a voltage measuring unit, a control unit, a voltage conversion circuit, a start switch, and a power start circuit. The voltage measuring unit measures the voltage of each of the multiple batteries. The voltage conversion circuit is disposed on the path from the battery pack to the control unit. The start switch is connected between the voltage conversion circuit and the battery pack. The power start circuit has an input terminal for receiving an external start signal. When the external start signal becomes a start logic signal, the start switch is turned on, and a monitoring signal indicating the logic state of the external start signal is output to the control unit. The power start circuit maintains the on state of the start switch as long as a start sustain signal is being input from the control unit. Furthermore, the control unit includes a line switch control unit, a start sustain control unit, and an OCV determination unit. When the logic state of the external start signal becomes start logic, the line switch control unit turns on the line switch connected in series with the battery pack. When the logic state of the external start signal becomes stop logic, the line switch control unit turns off the line switch. When the logic state of the external start signal becomes start logic, the start sustain control unit starts outputting the start sustain signal to the power start circuit. When the logic state of the external start signal becomes stop logic, the OCV determination unit acquires the voltage change of each of the plurality of batteries measured by the voltage measuring unit at predetermined time intervals. When the number of times the change is acquired reaches a predetermined number, the unit estimates the OCV of each of the plurality of batteries based on the changes acquired so far and records them, causing the start sustain control unit to stop outputting the start sustain signal.

[0017] According to this battery management device, after recording the OCV of each battery, the output of the start-up sustaining signal is immediately stopped, the start switch is turned off, and the power supply from the battery pack to the control unit is stopped. Therefore, the power consumption required to determine the OCV of each battery can be reduced. In particular, according to this battery management process, regardless of the convergence level of the voltage of each battery, the OCV of each battery can be determined at a preset time, and the power supply from the battery pack to the control unit can be stopped. That is, for example, even if the current flowing through the battery pack immediately beforehand is large, and the convergence of the voltage of each battery takes time, the OCV of each battery can be determined and the power supply from the battery pack to the control unit can be stopped before that convergence. Therefore, according to this battery management device, the power consumption required to determine the OCV of each battery can be effectively reduced.

[0018] (4) The second battery management device disclosed in this specification is a device for managing a battery pack consisting of multiple batteries connected in series. It includes a voltage measuring unit, a control unit, a voltage conversion circuit, a start switch, and a power start circuit. The voltage measuring unit measures the voltage of each of the multiple batteries. The voltage conversion circuit is disposed on the path from the battery pack to the control unit. The start switch is connected between the voltage conversion circuit and the battery pack. The power start circuit has an input terminal for receiving an external start signal. When the external start signal becomes a start logic signal, the start switch is turned on, and a monitoring signal indicating the logic state of the external start signal is output to the control unit. The power start circuit maintains the on state of the start switch as long as a start sustain signal is being input from the control unit. Furthermore, the control unit includes a line switch control unit, a start sustain control unit, and an OCV determination unit. When the logic state of the external start signal becomes start, the line switch control unit turns the line switch connected in series with the battery pack on. When the logic state of the external start signal becomes stop, the line switch control unit turns the line switch off. When the logic state of the external start signal becomes start, the start sustain control unit starts outputting the start sustain signal to the power start circuit. When the logic state of the external start signal becomes stop, the OCV determination unit acquires the voltage change of each of the plurality of batteries measured by the voltage measuring unit at predetermined time intervals. Whenever the number of acquisitions of the change reaches a predetermined number, it estimates the OCV of each of the plurality of batteries based on the changes acquired so far and records them. When a predetermined time has elapsed since the line switch became off, the start sustain control unit stops outputting the start sustain signal.

[0019] According to this battery management device, if the OCV of each battery is recorded, the output of the start-up sustaining signal is immediately stopped, the start switch is turned off, and the power supply from the battery pack to the control unit is stopped. Therefore, the power consumption required to determine the OCV of each battery can be reduced. In particular, according to this battery management process, regardless of the convergence level of the voltage of each battery, the OCV of each battery can be determined at a preset time, and the power supply from the battery pack to the control unit can be stopped. That is, for example, even if the current flowing through the battery pack immediately before is large, thus taking time for the voltage convergence of each battery, the OCV of each battery can be determined and the power supply from the battery pack to the control unit can be stopped before convergence. Therefore, according to this battery management device, the power consumption required to determine the OCV of each battery can be effectively reduced.

[0020] (5) In the above-described battery management device, it can also be configured such that when the logic state of the external start signal becomes the stop logic, the OCV determination unit acquires the voltage change of each of the plurality of batteries measured by the voltage measuring unit at predetermined time intervals. When the voltage change of each of the plurality of batteries is all below a predetermined change, the OCV determination unit causes the start-up maintenance control unit to stop the output of the start-up maintenance signal. When the logic state of the external start signal becomes the start logic again, the OCV determination unit records the voltage of each of the plurality of batteries at that time point as OCV and controls the line switch control unit to turn the line switch on. According to this battery management device, the voltage of each battery is recorded as OCV with more sufficient convergence, thus enabling the determination of the OCV of each battery with higher accuracy. Furthermore, it enables the execution of predetermined processing using OCV (e.g., SOC estimation) with higher accuracy.

[0021] Furthermore, the technology disclosed in this specification can be implemented in various ways, such as by a battery management device, a battery device having a battery management device and a battery pack, their management methods, a computer program for implementing these methods, and a non-transitory recording medium on which the computer program is recorded. Attached Figure Description

[0022] Figure 1 This is an explanatory diagram that schematically illustrates the structure of the battery device 100 in the first embodiment.

[0023] Figure 2 This is a timing diagram illustrating the battery management process of the first embodiment.

[0024] Figure 3 This is an explanatory diagram illustrating an example of the status of each signal and each switch in the battery management process of the first embodiment.

[0025] Figure 4 This is an explanatory diagram illustrating an example of the state of each signal, the state of each switch, and the state of the voltage Vcell of each battery 12 during a specific period in the battery management process of the first embodiment.

[0026] Figure 5 This is an explanatory diagram illustrating an example of the state of each signal, the state of each switch, and the state of the voltage Vcell of each battery 12 during a specific period in the battery management process of the second embodiment.

[0027] Figure 6 This is an explanatory diagram illustrating an example of the state of each signal, the state of each switch, and the state of the voltage Vcell of each battery 12 during a specific period in the battery management process of the third embodiment.

[0028] Figure 7 This is an explanatory diagram illustrating another example of the state of each signal, the state of each switch, and the state of the voltage Vcell of each battery 12 during a specific period in the battery management process of the third embodiment.

[0029] Figure 8 This is an explanatory diagram illustrating an example of the state of each signal, the state of each switch, and the state of the voltage Vcell of each battery 12 during a specific period in the battery management process of the fourth embodiment.

[0030] Figure 9 This is an explanatory diagram illustrating an example of the state of each signal, the state of each switch, and the state of the voltage Vcell of each battery 12 during a specific period in the battery management process of the fifth embodiment. Detailed Implementation

[0031] A. First implementation method:

[0032] A-1. Structure of battery device 100:

[0033] Figure 1 This is an explanatory diagram that schematically shows the structure of the battery device 100 in the first embodiment. The battery device 100 includes a battery pack 10 and a battery management device 20.

[0034] The battery pack 10 has a structure in which multiple batteries 12 are connected in series. In this embodiment, the battery pack 10 consists of four batteries 12. Each battery 12 is, for example, a lithium-ion battery. The battery pack 10 is connected to a load (not shown) and an external power source via a positive terminal 42 and a negative terminal 44.

[0035] The battery management device 20 is a device for managing the battery device 100, which includes the battery pack 10. The battery management device 20 includes a voltmeter 22, an ammeter 24, a monitoring unit 28, a voltage conversion circuit 32, a start switch 34, a power start circuit 36, a line switch 40, a control unit 60, and a recording unit 70.

[0036] A voltmeter 22 is provided for each battery 12. Each voltmeter 22 is connected in parallel with each battery 12, measures the voltage of each battery 12, and outputs a signal indicating the voltmeter reading to a monitoring unit 28. An ammeter 24 is connected in series with the battery pack 10. The ammeter 24 measures the current flowing through the battery pack 10 and outputs a signal indicating the ammeter reading to the monitoring unit 28. Based on the signals received from the voltmeter 22 and the ammeter 24, the monitoring unit 28 outputs signals indicating the voltage of each battery 12 and the current flowing through the battery pack 10 to the control unit 60. The voltmeter 22 and the monitoring unit 28 are examples of a voltmeter measuring unit.

[0037] A line switch 40 is disposed between the battery pack 10 and the negative terminal 44. The line switch 40 is controlled to be turned on / off by the control unit 60, thereby opening and closing the connection between the battery pack 10 and the load and external power source. For example, a MOSFET or a relay may be used as the line switch 40.

[0038] The control unit 60 is configured using, for example, a CPU, a multi-core CPU, or a programmable device (FPGA, PLD, etc.) to control the operation of the battery management device 20. The control unit 60 functions as a line switch control unit 61, a start-up maintenance control unit 62, an OCV determination unit 63, and a timer unit 64. The functions of these units will be explained in conjunction with the battery management process described later.

[0039] The recording unit 70 is composed of, for example, ROM, RAM, hard disk drive (HDD), etc., and stores various programs and data, or serves as a working area or data storage area when performing various processes. For example, the recording unit 70 stores a computer program for performing the battery management process described later. This computer program is provided, for example, in a computer-readable recording medium (not shown) such as a CD-ROM, DVD-ROM, or USB memory, and is stored in the recording unit 70 by being installed in the battery device 100.

[0040] A voltage conversion circuit 32 is provided on the path 35 for supplying power from the battery pack 10 to the control unit 60. The voltage conversion circuit 32 is a circuit that converts the voltage of the power from the battery pack 10 and supplies it to the control unit 60. A start switch 34 is disposed between the battery pack 10 and the voltage conversion circuit 32 in the path 35, and opens and closes the connection between the battery pack 10 and the voltage conversion circuit 32. For example, a MOSFET or a relay can be used as the start switch 34. A power-on circuit 36 ​​is a circuit that controls the on / off state of the start switch 34. The power-on circuit 36 ​​has an input terminal 37 that receives an external start signal So via a signal receiving terminal 38 (EN).

[0041] A-2. Battery Management Procedures:

[0042] Next, the battery management process performed by the battery management device 20 in the battery device 100 of the first embodiment will be described. The battery management process of the first embodiment is a process of switching the connection state between the battery pack 10 and the load and the external power source by opening and closing the circuit switch 40, or determining the OCV of each battery 12 constituting the battery pack 10. The battery management process is repeatedly executed during the operation of the battery device 100. Figure 2 This is a timing diagram illustrating the battery management process of the first embodiment. Figure 3 This is an explanatory diagram illustrating an example of the status of each signal and each switch in the battery management process of the first embodiment. Figure 4 This refers to a specific period in the battery management process of the first embodiment. Figure 3 The diagram illustrates an example of the status of each signal, each switch, and the voltage Vcell of each battery 12 during the period T1).

[0043] like Figure 2 As shown, the power-on circuit 36 ​​( Figure 1 The power-on circuit 36 ​​monitors whether the external start signal So, input from the input terminal 37 of the power-on circuit 36, indicates a start logic (S110). The external start signal So is a signal input via the signal receiving terminal 38 to switch the battery device 100 between a start state and a stop state. If the external start signal So indicates a start logic (S110: Yes), the power-on circuit 36 ​​turns on the start switch 34 (S120). Figure 3 At time t1), power supply begins from the battery pack 10 to the control unit 60 via the voltage conversion circuit 32. Additionally, the power-on circuit 36 ​​begins outputting a monitoring signal Sm indicating the logic state of the external start signal So to the control unit 60 (S120). Then, the power-on circuit 36 ​​monitors whether the external start signal So has become a stopped logic (S122). If the external start signal So has become a stopped logic (S122: Yes), the logic state of the monitoring signal Sm is switched to the stopped logic (S124).

[0044] If power is supplied to the control unit 60, the control unit 60 monitors whether the logic state of the external start signal So, represented by the monitoring signal Sm input from the power start circuit 36, is start logic (S210). If the logic state of the external start signal So, represented by the monitoring signal Sm, is start logic (S210: Yes), the line switch control unit 61 of the control unit 60 sets the line switch 40 to the ON state (S220). Figure 3 At time t1). Thus, the battery pack 10 is connected to the load and the external power supply. In addition, the start-up sustain control unit 62 of the control unit 60 starts to output a start-up sustain signal Sh to the power start-up circuit 36 ​​(S220). The power start-up circuit 36 ​​monitors whether a start-up sustain signal Sh is input from the control unit 60 (S130), and maintains the on state of the start switch 34 as long as a start-up sustain signal Sh is input (S130: yes). Furthermore, as long as a start-up sustain signal Sh is input (S130: yes), the power start-up circuit 36 ​​continuously monitors whether the external start signal So has reached the stop logic (S122).

[0045] Then, the control unit 60 monitors whether the logic state of the external start signal So, represented by the monitoring signal Sm input from the power start circuit 36, is the stop logic (S230). If the logic state of the external start signal So, represented by the monitoring signal Sm, is the stop logic (S230: Yes), then the line switch control unit 61 of the control unit 60 puts the line switch 40 into the open state (S240). Figure 3 as well as Figure 4 At time t2). As a result, the connection between the battery pack 10 and the load and the external power source is disconnected, and the voltage Vcell of each battery 12 changes in a manner that converges towards OCV.

[0046] When the line switch 40 is in the open state (S240), the OCV determination unit 63 of the control unit 60 begins the OCV determination process for each battery 12 as described below (S250). That is, as Figure 4 As shown, the OCV determination unit 63 of the control unit 60 acquires the change in voltage Vcell of each battery 12 (the change in voltage per predetermined time interval) ΔVcell, measured by the voltmeter 22 and the monitoring unit 28, according to a predetermined time interval measured by the timer unit 64. When the change in voltage Vcell ΔVcell of each battery 12 is all below the predetermined change ΔVth, the OCV determination unit 63 records the voltage Vcell of each battery 12 at that moment as OCV in the recording unit 70. When the change in voltage Vcell ΔVcell of each battery 12 is all below the predetermined change ΔVth, it is considered that the voltage Vcell of each battery 12 has sufficiently converged and can be regarded as OCV, and therefore the voltage Vcell at that moment is recorded as OCV.

[0047] After the OCV determination process begins (S250), the control unit 60 monitors whether the logic state of the external start signal So, represented by the monitoring signal Sm, is stopped (S260), and monitors whether the OCV determination process has been completed (S270). If the logic state of the external start signal So, represented by the monitoring signal Sm, is stopped (S260: Yes), and the OCV determination process is completed (S270: Yes), then the OCV determination unit 63 of the control unit 60 causes the start sustain control unit 62 to stop outputting the start sustain signal Sh (S280). Figure 3 as well as Figure 4At time t3). If the output of the start-up sustaining signal Sh stops, the power-on circuit 36 ​​determines that no start-up sustaining signal Sh has been input from the control unit 60 (S130: No), and sets the start switch 34 to the off state (S140). As a result, the power supply from the battery pack 10 to the control unit 60 via the voltage conversion circuit 32 stops, and the power consumption of the control unit 60 becomes zero. Furthermore, before the OCV determination process is completed (S270: No), if the logic state of the external start signal So represented by the monitoring signal Sm becomes the start logic (S260: No), the control unit 60 similarly executes the process after S220 described above. Afterward, the above process is repeatedly executed.

[0048] A-3. Effects of the first implementation method:

[0049] As explained above, the battery management device 20 of this embodiment is a device for managing a battery pack 10 formed by connecting multiple batteries 12 in series. The battery management device 20 includes a voltmeter 22 and a monitoring unit 28, a control unit 60, a voltage conversion circuit 32, a start switch 34, and a power start circuit 36. The voltmeter 22 and the monitoring unit 28 measure the voltage Vcell of each of the multiple batteries 12. The voltage conversion circuit 32 is provided on the path 35 for supplying power from the battery pack 10 to the control unit 60. The start switch 34 is connected between the voltage conversion circuit 32 and the battery pack 10. The power start circuit 36 ​​has an input terminal 37 for receiving an external start signal So. When the external start signal So becomes a start logic signal, the start switch 34 is turned on, and a monitoring signal Sm indicating the logic state of the external start signal So is output to the control unit 60. The power start circuit 36 ​​maintains the on state of the start switch 34 as long as a start sustain signal Sh is being input from the control unit 60.

[0050] In addition, the control unit 60 includes a line switch control unit 61, a start-up maintenance control unit 62, and an OCV determination unit 63. When the logic state of the external start signal So indicated by the monitoring signal Sm becomes start-up logic, the line switch control unit 61 sets the line switch 40, which is connected in series with the battery pack 10, to the on state; when the logic state of the external start signal So indicated by the monitoring signal Sm becomes stop-up logic, the line switch 40 is set to the off state. If the logic state of the external start signal So indicated by the monitoring signal Sm becomes start-up logic, the start-up maintenance control unit 62 starts outputting a start-up maintenance signal Sh to the power start-up circuit 36. When the logic state of the external start signal So indicated by the monitoring signal Sm becomes stop-up logic, the OCV determination unit 63 acquires the change in voltage Vcell of each of the multiple batteries 12 at predetermined time intervals, ΔVcell. When the change in voltage Vcell ΔVcell of each of the multiple batteries 12 is all below a predetermined change ΔVth, the voltage Vcell of each of the multiple batteries 12 at that moment is recorded as OCV, and the start-up maintenance control unit 62 stops outputting the start-up maintenance signal Sh.

[0051] Thus, according to the battery management device 20 of this embodiment, after the logic state of the external start signal So, indicated by the monitoring signal Sm, becomes the stop logic and the line switch 40 becomes the open state, if the change amount ΔVcell of the voltage Vcell of each battery 12 is all below a predetermined change amount ΔVth, that is, if the voltage Vcell of each battery 12 sufficiently converges, then the voltage Vcell at that moment is recorded as OCV, thereby enabling high-precision determination of the OCV of each battery 12. Furthermore, it is possible to perform the prescribed processing using OCV (e.g., SOC estimation) with high precision. In addition, according to the battery management device 20 of this embodiment, if the OCV is recorded, the output of the start sustain signal Sh is immediately stopped, the start switch 34 becomes the open state, and the power supply from the battery pack 10 to the control unit 60 is stopped, thereby reducing the power consumption required to determine the OCV of each battery 12.

[0052] B. Second implementation method:

[0053] Figure 5 This is an explanatory diagram illustrating an example of the states of each signal, each switch, and the voltage Vcell of each battery 12 during a specific period in the battery management process of the second embodiment. Hereinafter, only the differences between the battery management process of the second embodiment and the battery management process of the first embodiment described above will be explained; for points that are the same as those in the battery management process of the first embodiment, their descriptions will be omitted as appropriate.

[0054] In the battery management process of the second embodiment, the OCV determination process of each battery 12 is completed. Figure 2 S270: Yes), the output of the start sustain signal Sh stops (S280), and the start switch 34 is turned off (S140). Figure 5 At time t3), when the logic state of the next external start signal So becomes the start logic ( Figure 5 At time t4, the OCV determination unit 63 of the control unit 60 records the voltage Vcell of each battery 12 at that time as OCV (that is, updates the OCV of each battery 12 recorded in the recording unit 70), and then the control line switch control unit 61 turns the line switch 40 on.

[0055] Thus, in the battery management process of the second embodiment, if the logic state of the external start signal So, represented by the monitoring signal Sm, becomes the stop logic, the OCV determination unit 63 of the control unit 60 acquires the voltage Vcell change ΔVcell of each battery 12 measured by the voltmeter 22 and the monitoring unit 28 at predetermined time intervals. If the voltage Vcell change ΔVcell of each battery 12 is all below a predetermined change ΔVth, the start-up maintenance control unit 62 stops outputting the start-up maintenance signal Sh. When the logic state of the external start signal So becomes the start logic again, the voltage Vcell of each battery 12 at that moment is recorded as OCV, and the line switch control unit 61 sets the line switch 40 to the on state. Therefore, according to the battery management process of the second embodiment, the voltage Vcell of each battery 12 that is more fully converged is recorded as OCV, thus enabling the determination of the OCV of each battery 12 with higher accuracy. Furthermore, it is possible to perform the prescribed processing using OCV (e.g., SOC estimation) with higher accuracy.

[0056] C. Third implementation method:

[0057] Figure 6 This is an explanatory diagram illustrating an example of the states of each signal, each switch, and the voltage Vcell of each battery 12 during a specific period in the battery management process of the third embodiment. Hereinafter, only the differences between the battery management process of the third embodiment and the battery management process of the first embodiment described above will be explained; for points that are the same as those in the battery management process of the first embodiment, their descriptions will be omitted as appropriate.

[0058] In the battery management process of the third embodiment, the OCV determination process ( Figure 2The method of S250 is different from the battery management process of the first embodiment described above. Specifically, when the OCV determination unit 63 of the control unit 60 starts the OCV determination process, as shown in the figure... Figure 6 As shown, the voltage change ΔVcell of each battery 12 is acquired at predetermined time intervals measured by the timer unit 64, and the unit monitors whether all voltage change ΔVcell values ​​of each battery 12 are below a predetermined change ΔVth. Here, before all voltage change ΔVcell values ​​of each battery 12 are below the predetermined change ΔVth, the OCV determination unit 63 estimates the OCV of each battery 12 based on the voltage change ΔVcell values ​​acquired so far, whenever the number of times the voltage change ΔVcell is acquired reaches a predetermined number, and records the estimated OCV in the recording unit 70. For example, in... Figure 6 In the example shown, whenever the change in voltage Vcell ΔVcell is measured 3 times or more ( Figure 6 At times ta, tb, and tc, the OCV of each battery 12 is estimated and recorded. Then, when the voltage change ΔVcell of each battery 12 becomes below the specified change ΔVth, ( Figure 6 At time t3), the OCV determination unit 63 records the voltage Vcell of each battery 12 at that time as OCV in the recording unit 70 (that is, updates the OCV of each battery 12 recorded in the recording unit 70).

[0059] Furthermore, the estimation method by which the OCV determination unit 63 estimates the OCV of each battery 12 can be executed in any manner. For example, it can employ the following method: based on the change in voltage Vcell ΔVcell of each battery 12 obtained so far, calculate an approximate curve representing the change in voltage Vcell of each battery 12 over time, find the convergence value of voltage Vcell of each battery 12 in the approximate curve, and estimate the convergence value as OCV.

[0060] Thus, in the battery management process of the third embodiment, when the logic state of the external start signal So, represented by the monitoring signal Sm, becomes the stop logic, the OCV determination unit 63 acquires the voltage Vcell change ΔVcell of each battery 12 measured by the voltmeter 22 and the monitoring unit 28 at predetermined time intervals. Before all voltage Vcell change ΔVcells of each battery 12 become below a predetermined change ΔVth, whenever the number of times the voltage Vcell change ΔVcell is acquired reaches a predetermined number, the OCV of each battery 12 is estimated based on the voltage Vcell change ΔVcells acquired so far and recorded. Therefore, according to the third embodiment, the OCV of each battery 12 can be determined at a relatively early time. Furthermore, the predetermined processing using OCV (e.g., SOC estimation) can be performed at a relatively early time.

[0061] In addition, such as Figure 7 As shown, before the voltage change ΔVcell of each battery 12 becomes below the specified change ΔVth, the logic state of the external start signal So becomes the start logic. Figure 7 At time td), the line switch 40 becomes closed, making it impossible to measure the OCV of each battery 12. However, according to the battery management process of the third embodiment, even in such a case, the OCV estimation results previously performed (e.g., Figure 7 The OCV of each battery 12 is determined by estimating the time ta. This avoids situations where the prescribed processing using OCV (e.g., SOC estimation) cannot be performed.

[0062] D. Fourth Implementation Method:

[0063] Figure 8 This is an explanatory diagram illustrating an example of the states of each signal, each switch, and the voltage Vcell of each battery 12 during a specific period in the battery management process of the fourth embodiment. Hereinafter, only the differences between the battery management process of the fourth embodiment and the battery management process of the first embodiment will be described; for points that are the same as those in the battery management process of the first embodiment, their descriptions will be omitted as appropriate.

[0064] In the battery management process of the fourth embodiment, the OCV determination process ( Figure 2 The method of S250 is different from the battery management process of the first embodiment described above. Specifically, when the OCV determination unit 63 of the control unit 60 starts the OCV determination process, as shown in the figure... Figure 8As shown, the voltage change ΔVcell of each battery 12 is acquired at predetermined time intervals measured by the timer unit 64. When the number of acquisitions of the voltage change ΔVcell reaches a predetermined number, the OCV of each battery 12 is estimated based on the voltage change ΔVcell acquired so far, and the estimated OCV is recorded in the recording unit 70. For example, in Figure 8 In the example shown, when the change in voltage Vcell ΔVcell is measured 4 times ( Figure 8 At time t5, the OCV of each battery 12 is estimated and recorded. Furthermore, the estimation method for estimating the OCV of each battery 12 based on the change in voltage Vcell ΔVcell can be the same as the estimation method described in the third embodiment above. Afterwards, the OCV determination unit 63 immediately causes the start-up maintenance control unit 62 to stop outputting the start-up maintenance signal Sh.

[0065] Thus, in the battery management process of the fourth embodiment, when the logic state of the external start signal So represented by the monitoring signal Sm becomes the stop logic, the OCV determination unit 63 acquires the voltage Vcell change ΔVcell of each battery 12 measured by the voltmeter 22 and the monitoring unit 28 at predetermined time intervals. When the number of times the voltage Vcell change ΔVcell is acquired reaches a predetermined number, the OCV of each battery 12 is estimated based on the voltage Vcell change ΔVcell acquired so far and recorded, causing the start-up maintenance control unit 62 to stop the output of the start-up maintenance signal Sh. Therefore, according to the battery management process of the fourth embodiment, if the OCV of each battery 12 is recorded, the output of the start-up maintenance signal Sh is immediately stopped, the start switch 34 is turned off, and the power supply from the battery pack 10 to the control unit 60 is stopped, thereby reducing the power consumption required to determine the OCV of each battery 12. In particular, according to the battery management process of the fourth embodiment, regardless of the convergence degree of the voltage Vcell of each battery 12, the determination of the OCV of each battery 12 is completed at a predetermined time, and the power supply from the battery pack 10 to the control unit 60 is stopped. Therefore, for example, even if the current flowing through the battery pack 10 is large at the imminent moment, and the convergence of the voltage Vcell of each battery 12 takes time, the determination of the OCV of each battery 12 can be completed before the convergence and the power supply from the battery pack 10 to the control unit 60 can be stopped. Thus, the power consumption required to determine the OCV of each battery 12 can be effectively reduced.

[0066] E. Fifth implementation method:

[0067] Figure 9This is an explanatory diagram illustrating an example of the states of each signal, each switch, and the voltage Vcell of each battery 12 during a specific period in the battery management process of the fifth embodiment. Hereinafter, only the differences between the battery management process of the fifth embodiment and the battery management process of the first embodiment described above will be explained; for points that are the same as those in the battery management process of the first embodiment, their descriptions will be omitted as appropriate.

[0068] In the battery management process of the fifth embodiment, the OCV determination process ( Figure 2 The method of S250 is different from the battery management process of the first embodiment described above. Specifically, when the OCV determination unit 63 of the control unit 60 starts the OCV determination process, as shown in the figure... Figure 9 As shown, the voltage change ΔVcell of each battery 12 is acquired at predetermined time intervals measured by the timer unit 64. Whenever the number of acquisitions of the voltage change ΔVcell reaches a predetermined number, the OCV of each battery 12 is estimated based on the voltage change ΔVcell acquired so far and recorded in the recording unit 70. Furthermore, the estimation method for estimating the OCV of each battery 12 based on the voltage change ΔVcell can be the same as the estimation method in the third embodiment described above. Additionally, when a predetermined time has elapsed since the line switch 40 was set to the open state (i.e., since the start of the OCV determination process), the OCV determination unit 63 causes the start-up maintenance control unit 62 to stop outputting the start-up maintenance signal Sh. For example, in... Figure 9 In the example shown, whenever the change in voltage Vcell ΔVcell is acquired 3 times or more, the OCV of each battery 12 is estimated and recorded. At time t6, after a specified time has elapsed since the line switch 40 is in the open state, the output of the start-up sustaining signal Sh is stopped.

[0069] Thus, in the battery management process of the fifth embodiment, when the logic state of the external start signal So represented by the monitoring signal Sm becomes the stop logic, the OCV determination unit 63 acquires the voltage Vcell change ΔVcell of each battery 12 measured by the voltmeter 22 and the monitoring unit 28 at predetermined time intervals. Whenever the number of times the voltage Vcell change ΔVcell is acquired reaches a predetermined number, the OCV of each battery 12 is estimated based on the voltage Vcell change ΔVcell acquired so far and recorded. After a predetermined time has elapsed after the line switch 40 is set to the open state, the start-up maintenance control unit 62 stops the output of the start-up maintenance signal Sh. Therefore, according to the battery management process of the fifth embodiment, if the OCV is recorded, the output of the start-up maintenance signal Sh is immediately stopped, the start switch 34 is set to the open state, and the power supply from the battery pack 10 to the control unit 60 is stopped, thus reducing the power consumption required to determine the OCV of each battery 12. In particular, according to the fifth embodiment, regardless of the convergence degree of the voltage Vcell of each battery 12, the determination of the OCV of each battery 12 is completed at a predetermined time, and the power supply from the battery pack 10 to the control unit 60 is stopped. For example, even if the current flowing through the battery pack 10 is large at the imminent moment, and the convergence of the voltage Vcell of each battery 12 takes time, the determination of the OCV of each battery 12 can be completed and the power supply from the battery pack 10 to the control unit 60 can be stopped before the convergence, thus effectively reducing the power consumption required to determine the OCV of each battery 12.

[0070] F. Variations:

[0071] The technology disclosed in this specification is not limited to the above-described embodiments and can be modified in various ways without departing from its spirit, for example, the following modifications are also possible.

[0072] The structure of the battery device 100 in the above embodiments is merely one example and can be modified in various ways. For example, in the above embodiments, the number of batteries 12 constituting the battery pack 10 can be arbitrarily changed. In addition, in the above embodiments, the power start-up circuit 36 ​​and the control unit 60 can also be integrated into one structure.

[0073] The battery management process described in the above embodiments is merely one example and can be modified in various ways. For instance, the OCV determination process for each battery 12 in the battery management process can be modified based on the current value flowing through the battery pack 10 immediately before the process is performed (immediately before the line switch 40 is set to the open state). Specifically, when the current flowing through the battery pack 10 is relatively small, it is assumed that the convergence time of the voltage Vcell of each battery 12 is relatively short. Therefore, as in the first embodiment described above, the following method is adopted: the start switch 34 is kept in the on state until the change in voltage Vcell of each battery 12, ΔVcell, all become below the specified change ΔVth, thereby prioritizing the improvement of the accuracy of OCV determination. On the other hand, when the current flowing through the battery pack 10 is relatively large, it is assumed that the convergence time of the voltage Vcell of each battery 12 is relatively long. Therefore, as in the third and fourth embodiments described above, the following method is adopted: the start switch 34 is set to the off state before the change in voltage Vcell of each battery 12, ΔVcell, all become below the specified change ΔVth, thereby prioritizing the reduction of power consumption.

[0074] In addition, in the third to fifth embodiments described above, similar to the second embodiment, after the OCV determination process of each battery 12 is completed, the output of the start sustain signal Sh stops, and the start switch 34 becomes open, when the logic state of the next external start signal So becomes the start logic, the voltage Vcell of each battery 12 at that moment is recorded as OCV, and then the line switch 40 is turned on.

[0075] Explanation of reference numerals in the attached figures

[0076] 10: Battery pack; 12: Storage battery; 20: Battery management device; 22: Voltmeter; 24: Ammeter; 28: Monitoring unit; 32: Voltage conversion circuit; 34: Start switch; 35: Path; 36: Power start circuit; 37: Input terminal; 38: Signal receiving terminal; 40: Line switch; 42: Positive terminal; 44: Negative terminal; 60: Control unit; 61: Line switch control unit; 62: Start-up maintenance control unit; 63: OCV determination unit; 64: Timer unit; 70: Recording unit; 100: Battery device; Sh: Start-up maintenance signal; Sm: Monitoring signal; So: External start signal.

Claims

1. A battery management device for managing a battery pack consisting of multiple batteries connected in series, wherein, The battery management device includes: A voltage measuring unit that measures the voltage of each of the plurality of batteries; Control Department; A voltage conversion circuit is provided on the path from the battery pack to the control unit for supplying power; A power switch is connected between the voltage conversion circuit and the battery pack; as well as The power-on circuit has an input terminal for receiving an external start signal. When the external start signal triggers a start logic, it turns the start switch on and outputs a monitoring signal indicating the logic state of the external start signal to the control unit. The circuit maintains the on state of the start switch as long as a start sustain signal is being input from the control unit. The control unit has: The circuit switch control unit, when the logic state of the external start signal becomes the start logic, makes the circuit switch connected in series with the battery pack into the on state, and when the logic state of the external start signal becomes the stop logic, makes the circuit switch into the off state. The start-up sustaining control unit starts outputting the start-up sustaining signal to the power-on circuit when the logic state of the external start signal becomes start logic; as well as The OCV determination unit, when the logic state of the external start signal becomes the stop logic, acquires the voltage change of each of the plurality of batteries measured by the voltage measuring unit at a predetermined time interval. When the voltage change of each of the plurality of batteries is all below a predetermined change, the unit records the voltage of each of the plurality of batteries at this moment as OCV and causes the start maintenance control unit to stop the output of the start maintenance signal.

2. The battery management device according to claim 1, wherein, When the logic state of the external start signal becomes the stop logic, the OCV determination unit acquires the voltage change of each of the plurality of batteries measured by the voltage measurement unit at predetermined time intervals. Before the voltage change of each of the plurality of batteries falls below a predetermined amount, whenever the number of acquisitions of the change amount reaches a predetermined number, the OCV of each of the plurality of batteries is estimated based on the change amount acquired so far and they are recorded.

3. A battery management device for managing a battery pack consisting of multiple batteries connected in series, wherein, The battery management device includes: A voltage measuring unit that measures the voltage of each of the plurality of batteries; Control Department; A voltage conversion circuit is provided on the path from the battery pack to the control unit for supplying power; A power switch is connected between the voltage conversion circuit and the battery pack; as well as The power-on circuit has an input terminal for receiving an external start signal. When the external start signal triggers a start logic, it turns the start switch on and outputs a monitoring signal indicating the logic state of the external start signal to the control unit. The circuit maintains the on state of the start switch as long as a start sustain signal is being input from the control unit. The control unit has: The circuit switch control unit, when the logic state of the external start signal becomes the start logic, makes the circuit switch connected in series with the battery pack into the on state, and when the logic state of the external start signal becomes the stop logic, makes the circuit switch into the off state. The start-up sustaining control unit starts outputting the start-up sustaining signal to the power-on circuit when the logic state of the external start signal becomes start logic; as well as The OCV determination unit acquires the voltage change of each of the plurality of batteries measured by the voltage measuring unit at predetermined time intervals when the logic state of the external start signal becomes the stop logic. When the number of acquisitions of the change reaches a predetermined number, the unit estimates the OCV of each of the plurality of batteries based on the change acquired so far and records them, and causes the start-up maintenance control unit to stop the output of the start-up maintenance signal.

4. A battery management device for managing a battery pack consisting of multiple batteries connected in series, wherein, The battery management device includes: A voltage measuring unit that measures the voltage of each of the plurality of batteries; Control Department; A voltage conversion circuit is provided on the path from the battery pack to the control unit for supplying power; A power switch is connected between the voltage conversion circuit and the battery pack; as well as The power-on circuit has an input terminal for receiving an external start signal. When the external start signal triggers a start logic, it turns the start switch on and outputs a monitoring signal indicating the logic state of the external start signal to the control unit. The circuit maintains the on state of the start switch as long as a start sustain signal is being input from the control unit. The control unit has: The circuit switch control unit, when the logic state of the external start signal becomes the start logic, makes the circuit switch connected in series with the battery pack into the on state, and when the logic state of the external start signal becomes the stop logic, makes the circuit switch into the off state. The start-up sustaining control unit starts outputting the start-up sustaining signal to the power-on circuit when the logic state of the external start signal becomes start logic; as well as The OCV determination unit acquires the voltage change of each of the plurality of batteries measured by the voltage measuring unit at predetermined time intervals when the logic state of the external start signal becomes the stop logic. Whenever the number of acquisitions of the change reaches a predetermined number, it estimates the OCV of each of the plurality of batteries based on the change acquired so far and records them. When a predetermined time has elapsed since the line switch became the open state, it causes the start sustain control unit to stop the output of the start sustain signal.

5. The battery management device according to any one of claims 1 to 4, wherein, When the logic state of the external start signal becomes the stop logic, the OCV determination unit acquires the voltage change of each of the plurality of batteries measured by the voltage measuring unit at predetermined time intervals. When the voltage change of each of the plurality of batteries is below a predetermined change, the start maintenance control unit stops the output of the start maintenance signal. When the logic state of the external start signal becomes the start logic again, the OCV determination unit records the voltage of each of the plurality of batteries at this moment as OCV and controls the line switch control unit to make the line switch turn on.

6. A method for managing a battery device, wherein, The battery device includes: A battery pack is composed of multiple batteries connected in series. A voltage measuring unit that measures the voltage of each of the plurality of batteries; Control Department; A voltage conversion circuit is provided on the path from the battery pack to the control unit for supplying power; A power switch is connected between the voltage conversion circuit and the battery pack; as well as The power-on circuit has an input terminal for receiving an external start signal. When the external start signal triggers a start logic, it turns the start switch on and outputs a monitoring signal indicating the logic state of the external start signal to the control unit. The circuit maintains the on state of the start switch as long as a start sustain signal is being input from the control unit. The management method for the battery device includes the following steps: When the logic state of the external start signal becomes the start logic, the circuit switch connected in series with the battery pack is turned on; when the logic state of the external start signal becomes the stop logic, the circuit switch is turned off. When the logic state of the external start signal becomes start logic, the start sustain signal is output to the power start circuit. as well as When the logic state of the external start signal becomes the stop logic, the voltage change of each of the plurality of batteries measured by the voltage measuring unit is acquired at a predetermined time interval. When the voltage change of each of the plurality of batteries is all below a predetermined change, the voltage of each of the plurality of batteries at this moment is recorded as OCV, and the output of the start sustain signal is stopped.

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