Battery monitoring system and battery monitoring device

Abstract

To provide a battery monitoring system, a battery monitoring device, and a battery monitoring method that are able to acquire current information of a battery at an acquisition timing synchronized with the timing of acquisition of voltage information by a battery measuring device.SOLUTION: A battery monitoring system according to an embodiment includes a battery measuring device and a battery monitoring device. The battery measuring device detects voltage information of a battery. The battery monitoring device acquires voltage information from the battery measuring device by means of wireless communication and acquires current information of a current flowing in the battery, from a current sensor. The battery monitoring device includes a control unit and a wireless communication unit. The wireless communication unit performs wireless communication with the battery measuring device for a predetermined period. A control unit outputs a voltage measurement instruction by means of the wireless communication unit and, based on timing of transmission of the voltage measurement instruction to the battery measuring device by the wireless communication unit, acquires the current information in a period for which the battery measuring device acquires the voltage information.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The disclosed embodiments relate to a battery monitoring system, a battery monitoring device, and a battery monitoring method. [Background technology]

[0002] To calculate the cell resistance of a battery, voltage and current information acquired at the same time is necessary. In addition, recent battery monitoring devices perform wireless communication with battery measurement devices in order to eliminate the need for harnesses. For example, in the battery monitoring system described in Patent Document 1, multiple battery measurement devices, each installed for each battery, measure the synchronized voltage and current of each battery and transmit the measured values ​​to the battery monitoring device via wireless communication. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-068611 Summary of the Invention [Problem to be solved by the invention]

[0004] However, in the battery monitoring system described in Patent Document 1, the current sensor and each battery measurement device must be connected by a harness, and as the number of battery measurement devices increases, the number of harnesses also increases, which hinders harness-less implementation.

[0005] Therefore, from the perspective of achieving harness-less operation, it is desirable for the battery monitoring device to send voltage measurement instructions to each battery measurement device via wireless communication, acquire battery voltage information from the battery measurement device, and acquire battery current information at a timing synchronized with the acquisition timing of the voltage information.

[0006] However, wireless communication has a communication timing error compared to wired communication, which means that the battery monitoring device cannot recognize the exact timing of voltage information acquisition by the battery measurement device, and may not be able to acquire battery current information at a timing synchronized with the acquisition timing of voltage information by the battery measurement device.

[0007] One aspect of the embodiment has been made in consideration of the above, and aims to provide a battery monitoring system, a battery monitoring device, and a battery monitoring method that can acquire battery current information at an acquisition timing synchronized with the acquisition timing of voltage information by a battery measuring device. [Means for solving the problem]

[0008] A battery monitoring system according to one aspect of an embodiment includes a battery measurement device and a battery monitoring device. The battery measurement device detects voltage information of a battery. The battery monitoring device acquires the voltage information from the battery measurement device via wireless communication, and acquires current information of a current flowing through the battery from a current sensor. The battery monitoring device includes a control unit and a wireless communication unit. The wireless communication unit wirelessly communicates with the battery measurement device at a predetermined cycle. The control unit causes the wireless communication unit to output a voltage measurement instruction, and acquires the current information at the time when the battery measurement device acquires voltage information based on the timing when the wireless communication unit transmits the voltage measurement instruction to the battery measurement device. Effect of the Invention

[0009] A battery monitoring system, a battery monitoring device, and a battery monitoring method according to one aspect of an embodiment have the advantage of being able to acquire battery current information at an acquisition timing synchronized with the acquisition timing of voltage information by a battery measurement device. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is an explanatory diagram of a battery monitoring system that uses wired communication. [Diagram 2]FIG. 2 is an explanatory diagram of the battery monitoring system according to the first embodiment. [Diagram 3] FIG. 3 is an explanatory diagram of a connection interval of the wireless communication unit according to the first embodiment. [Figure 4] FIG. 4 is a timing chart showing an example of the operation of the battery monitoring system according to the first embodiment. [Diagram 5] FIG. 5 is a flowchart illustrating an example of processing executed by the control unit according to the first embodiment. [Figure 6] FIG. 6 is an explanatory diagram of a battery monitoring system according to the second embodiment. [Figure 7] FIG. 7 is a timing chart showing an example of the operation of the battery monitoring system according to the second embodiment. [Figure 8] FIG. 8 is a flowchart illustrating an example of a process executed by the control unit according to the second embodiment. [Figure 9] FIG. 9 is a flowchart showing an example of processing executed by the battery measurement device according to the second embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of a battery monitoring system, a battery monitoring device, and a battery monitoring method will be described in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments described below. The battery monitoring system according to the embodiments is a system for monitoring the state of a lithium-ion battery for driving a vehicle mounted on, for example, an electric vehicle or a hybrid vehicle.

[0012] The battery monitoring system may be configured to monitor the state of any battery other than a vehicle battery. In the following, a battery monitoring system using wired communication will be described, followed by a battery monitoring system using wireless communication according to an embodiment.

[0013] [1. Battery monitoring system using wired communication] 1 is an explanatory diagram of a battery monitoring system 100 that uses wired communication. The battery monitoring system 100 is a system that calculates the cell resistance of a battery from voltage information on the voltage output from a battery in which multiple batteries are connected in series and current information on the current flowing through the battery, and monitors the deterioration state of the battery based on the resistance value of the cell resistance.

[0014] 1, the battery monitoring system 100 includes, for example, a plurality of battery measurement devices 110 and one battery monitoring device 120. A battery measurement device 110 is provided for each predetermined number of battery cells (stacks) connected in series. The battery measurement device 110 includes a measurement unit 111 that measures the voltage of each battery cell and outputs voltage information. The measurement units 111 are connected by a harness and transmit and receive voltage information by wired communication.

[0015] The battery monitoring device 120 includes a communication unit 121 and a control unit 122. The communication unit 121 is connected to each battery measurement device 110 by a harness, transmits a voltage measurement instruction to the battery measurement device 110 by wired communication, and receives voltage information of each battery cell from the battery measurement device 110 by wired communication. In addition, the communication unit 121 transmits the received voltage information to the control unit 122 by wired communication.

[0016] The control unit 122 receives current information from a current sensor 3 that measures the current flowing through the battery via wired communication. The control unit 122 calculates the cell resistance value of the battery from the synchronized voltage information and current information. That is, the control unit 122 calculates the cell resistance value at that time from the voltage information and current information measured at the same time. Then, the control unit 122 monitors the deterioration state of the battery based on the cell resistance value at each time.

[0017] Specifically, the control unit 122 transmits a command to the communication unit 121 to output a voltage measurement command to the battery measurement device 110. The communication unit 121 transmits a voltage measurement command to, for example, one battery measurement device 110 in accordance with the command from the control unit 122. The battery measurement device 110 that receives the voltage measurement command measures the voltage of the corresponding battery cell and transmits voltage information of the measured voltage and the voltage measurement command to the adjacent battery measurement device 110.

[0018] Thereafter, upon receiving a voltage measurement instruction, each battery measurement device 110 measures the voltage of the corresponding battery cell, and sequentially transmits a voltage measurement instruction to the next battery measurement device 110 together with the voltage information of the measured voltage and the voltage information received from the adjacent battery measurement device.

[0019] The battery measurement device 110 that finally receives the voltage measurement instruction transmits voltage information of the voltages measured by all of the battery measurement devices 110 to the battery monitoring device 120. In this manner, in the battery monitoring system 100, a series of processes from transmitting the voltage measurement instruction to acquiring the battery information is executed by wired serial communication.

[0020] Here, communication within the battery monitoring device 120, communication between the battery monitoring device 120 and the battery measurement device 110, communication between the battery measurement devices 110, and communication between the battery monitoring device 120 and the current sensor 3 are all wired communications. The time required for communication between each device is determined by the design.

[0021] Therefore, the battery monitoring device 120 can recognize the time from when it issues a command to send a voltage measurement instruction to the communication unit 121 to when each battery measurement device measures the voltage, without any delay. Therefore, the battery monitoring device 120 can calculate the cell resistance value from the current measured at the same time that the voltage was measured by each battery measurement device 110, that is, from synchronized voltage information and current information.

[0022] However, the battery monitoring system 100 requires harnesses to connect between the battery monitoring device 120 and the battery measurement device 110, and between each of the battery measurement devices 110, which hinders harness-less implementation and makes miniaturization difficult. Therefore, the battery monitoring system according to the embodiment achieves harness-less implementation by wirelessly communicating between the battery monitoring device and each of the battery measurement devices.

[0023] [2. Battery monitoring system according to the first embodiment] 2 is an explanatory diagram of a battery monitoring system 10 according to the first embodiment. As shown in Fig. 2, the battery monitoring system 10 includes, for example, a plurality of battery measurement devices 1-1 to 1-n (n is a natural number equal to or greater than 2) and one battery monitoring device 2.

[0024] Battery measurement devices 1-1 to 1-n are provided for each of a predetermined number of battery cells (stacks) connected in series. Battery measurement devices 1-1 to 1-n include a measurement unit 11 and a wireless communication unit 12. Measurement unit 11 measures the voltage of each battery cell and generates voltage information.

[0025] The wireless communication unit 12 is, for example, a communication integrated circuit (IC) having a BLE (Bluetooth Low Energy) (registered trademark) communication function. The wireless communication unit 12 performs wireless communication with the battery monitoring device 2 by BLE communication. The wireless communication unit 12 also performs wired communication with the measurement unit 11 by, for example, SPI (Serial Peripheral Interface) (registered trademark).

[0026] The battery monitoring device 2 includes a wireless communication unit 21 and a control unit 22. The wireless communication unit 21 is, for example, a communication IC equipped with a BLE communication function. The wireless communication unit 21 performs wireless communication with the wireless communication units 12 of the battery measurement devices 1-1 to 1-n using BLE communication. The wireless communication unit 21 also performs wired communication with the control unit 22 using, for example, SPI communication.

[0027] The control unit 22 includes a microcomputer having a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), etc., and various circuits. The control unit 22 controls the operation of the entire battery monitoring device 2 by the CPU executing a program stored in the ROM using the RAM as a working area.

[0028] For example, the control unit 22 issues a command to transmit a voltage measurement instruction to the wireless communication unit 21, acquires battery voltage information and current information, calculates a cell resistance value of the battery, and determines battery deterioration based on the cell resistance value, etc. Note that the control unit 22 may be partially or entirely configured with hardware such as an ASIC (Application Specific Integrated Circuit) or an FPGA (Field Programmable Gate Array).

[0029] The control unit 22 transmits a command to the wireless communication unit 21 via SPI communication to output a voltage measurement command to each of the battery measurement devices 1-1 to 1-n. In accordance with the command from the control unit 22, the wireless communication unit 21 transmits the voltage measurement command to each of the battery measurement devices 1-1 to 1-n via BLE communication, for example.

[0030] The wireless communication unit 12 of each battery measurement device 1-1 to 1-n that has received the voltage measurement instruction transmits the voltage measurement instruction to the measurement unit 11 via SPI communication. The measurement unit 11 that has received the voltage measurement instruction measures the voltage of the corresponding battery cell and transmits voltage information of the measured voltage to the wireless communication unit 12 via SPI communication. The wireless communication unit 12 transmits the voltage information received from the measurement unit 11 to the battery monitoring device 2 via BLE communication.

[0031] The wireless communication unit 21 of the battery monitoring device 2 transmits the voltage information received from the battery measurement devices 1-1 to 1-n to the control unit 22 by SPI communication. The control unit 22 calculates the cell resistance value of each battery cell based on the received voltage information of each battery cell and current information received by wired communication from the current sensor 3. Then, the control unit 22 monitors the deterioration state of the battery based on the cell resistance value of each battery cell.

[0032] In this way, in the battery monitoring system 10, the battery monitoring device 2 and each of the battery measurement devices 1-1 to 1-n communicate information wirelessly using BLE communication, so there is no need to connect the battery monitoring device 2 and each of the battery measurement devices 1-1 to 1-n with a harness. In other words, the battery monitoring system 10 can achieve a harness-less system between the battery monitoring device 2 and each of the battery measurement devices 1-1 to 1-n.

[0033] In the battery monitoring system 10, an error occurs in the communication timing between the battery monitoring device 2 and each of the battery measurement devices 1-1 to 1-n. Therefore, simply eliminating the harness does not allow the battery monitoring device 2 to recognize the accurate timing of voltage information acquisition by the battery measurement devices 1-1 to 1-n. As a result, the battery monitoring device 2 may not be able to acquire battery current information at a timing synchronized with the timing of voltage information acquisition by the battery measurement devices 1-1 to 1-n.

[0034] Specifically, when the wireless communication unit 21 of the battery monitoring device 2 is started, it first performs pairing for communication with the wireless communication units 12 of each of the battery measurement devices 1-1 to 1-n. At this time, the control unit 22 cannot recognize the timing (time) at which the pairing was established. Thereafter, the wireless communication unit 21 of the battery monitoring device 2 periodically performs BLE communication with the wireless communication units 12 of the battery measurement devices 1-1 to 1-n at a predetermined connection interval.

[0035] Fig. 3 is an explanatory diagram of a connection interval of the wireless communication unit 21 according to the first embodiment. As shown in Fig. 3, the wireless communication unit 21 sequentially performs BLE communication with each of the battery measurement devices 1-1 to 1-n during each connection interval.

[0036] Therefore, for example, when at time t01, the control unit 22 of the battery monitoring device 2 sends a command to the wireless communication unit 21 to instruct the battery measurement device 1-1 to measure a voltage, a voltage measurement command is immediately sent to the battery measurement device 1-1, and the voltage is measured by the battery measurement device 1-1.

[0037] As a result, the current information of the current measured at the timing when the voltage measurement instruction is transmitted from the control unit 22 to the wireless communication unit 21 and the voltage information of the voltage measured by the battery measurement device 1-1 become synchronized information. Therefore, the control unit 22 can calculate an accurate cell resistance value based on the synchronized current information and voltage information.

[0038] However, for example, when a command to measure a voltage is sent from the control unit 22 of the battery monitoring device 2 to the wireless communication unit 21 of the battery monitoring device 2 at time t02, the next time communication with the battery measurement device 1-1 will be possible is time t03, when the next connection interval begins.

[0039] Therefore, the current information of the current measured at the timing when the voltage measurement instruction is transmitted from the control unit 22 to the wireless communication unit 21 and the voltage information of the voltage measured by the battery measurement device 1-1 are not synchronized due to an error in the measurement timing, and the control unit 22 cannot calculate an accurate cell resistance value.

[0040] Therefore, the battery monitoring system 10 includes battery measurement devices 1-1 to 1-n and a battery monitoring device 2. The battery measurement devices 1-1 to 1-n detect voltage information of the batteries. The battery monitoring device 2 acquires the voltage information from the battery measurement devices 1-1 to 1-n by wireless communication such as BLE communication, and acquires current information of a current flowing through the battery from a current sensor 3.

[0041] The battery monitoring device 2 includes a control unit 22 and a wireless communication unit 21 that performs wireless communication with the battery measurement devices 1-1 to 1-n at a predetermined cycle. The control unit 22 then causes the wireless communication unit 21 to output a voltage measurement instruction, and acquires current information at the time when the battery measurement devices 1-1 to 1-n acquire voltage information based on the timing at which the wireless communication unit 21 transmits the voltage measurement instruction to the battery measurement devices 1-1 to 1-n. Next, a method of monitoring a battery by the battery monitoring system 10 will be described.

[0042] [3. Battery monitoring method according to the first embodiment] 4 is a timing chart showing an example of the operation of the battery monitoring system 10 according to the first embodiment. Here, the communication between the battery monitoring device 1 and the battery measurement device 1-1 will be described as an example.

[0043] As shown in FIG. 4, when monitoring a battery, the control unit 22 of the battery monitoring device 2 first transmits a command to the wireless communication unit 21 via SPI communication to instruct the wireless communication unit 21 to output a voltage measurement instruction to each battery measurement device 1-1 (step S1).

[0044] When the wireless communication unit 21 of the battery monitoring device 2 receives the command, it performs a predetermined process for communicating with the battery measurement device 1-1 and sets a waiting time until the start of the next communication (step S2).Then, at time t1 which is the next connection interval, the wireless communication unit 21 transmits a voltage measurement instruction command to the wireless communication unit 12 of the battery measurement device 1-1 by BLE communication (step S3).

[0045] Thereafter, when a predetermined communication prohibition period T has elapsed (step S4), the wireless communication unit 21 receives data from the wireless communication unit 12 of the battery measurement device 1-1 by BLE communication (step S5). At this time, the wireless communication unit 21 receives data from the battery measurement device 1-1 that is a reply to a command transmitted immediately before the command transmitted at time t1. If the immediately previous command was a voltage measurement instruction, the data received in step S5 includes voltage information in the previous connection interval.

[0046] Then, wireless communication unit 21 performs a predetermined process for communicating with control unit 22 and sets a waiting time until the start of the next communication (step S6), and then transmits the data received from battery measurement device 1-1 to control unit 22 by SPI communication (step S7). Control unit 22 performs a predetermined interrupt process (step S8), and the reception of data from wireless communication unit 21 is completed at time t2.

[0047] On the other hand, when the wireless communication unit 12 of the battery measurement device 1-1 receives a command to measure the voltage from the battery monitoring device 2, it performs predetermined processing for communicating with the measurement unit 11 and sets the waiting time until the next communication starts (step S9), and then transmits the command to the measurement unit 11 via SPI communication (step S10).

[0048] When the measurement unit 11 receives the voltage measurement command, it measures the voltage of the battery cell to be measured at time t3 and generates voltage information by A / D conversion (step S11).Then, the measurement unit 11 transmits the voltage information data to the wireless communication unit 12 by SPI communication (step S12).

[0049] At the next connection interval, the wireless communication unit 12 of the battery measurement device 1-1 receives, via BLE communication, a command for instructing the next voltage measurement from the battery monitoring device 2. Then, the wireless communication unit 12 performs a predetermined process for communicating with the wireless communication unit 21 of the battery monitoring device 2 and sets a waiting time until the start of the next communication (step S13), and when a predetermined communication prohibition period T has elapsed (step S14), transmits the current voltage information data to the battery monitoring device 2 via BLE communication (step S15).

[0050] When the wireless communication unit 21 of the battery monitoring device 2 receives the data, it performs a predetermined process for communicating with the control unit 22 and sets a waiting time until the start of the next communication (step S16), and then transmits the current voltage information data to the control unit 22 by SPI communication (step S17). After the control unit 22 performs a predetermined interrupt process (step S18), reception of the voltage information data from the wireless communication unit 21 is completed at time t4.

[0051] In this series of operations, the control unit 22 can recognize the timing to transmit a voltage measurement instruction command to the wireless communication unit 21 of the battery monitoring device 2, but cannot recognize the time t1 when the wireless communication unit 21 transmits the command to the battery measurement device 1-1, as described above. However, the control unit 22 can recognize the time t2 when the control unit 22 receives, from the wireless communication unit 21, the reception data from the battery measurement device 1-1 of the battery monitoring device 2.

[0052] A first time period A from when the wireless communication unit 21 of the battery monitoring device 2 sends a voltage measurement command to the battery measurement device 1-1 at time t1 to when the measurement unit 11 of the battery measurement device 1-1 measures the voltage of the battery cell at time t3 is predetermined by design.

[0053] In addition, a second time B from when the wireless communication unit 21 of the battery monitoring device 2 sends a voltage measurement command to the battery measurement device 1-1 at time t1 to when the process of sending the received data from the battery measurement device 1-1 to the control unit 22 is completed at time t2 is predetermined by design.

[0054] Therefore, the control unit 22 acquires current information of the current measured by the current sensor 3 from the current sensor 3 at time t3, which is the time t2 when the reception data from the battery measurement device 1-1 is received plus the time obtained by subtracting the second time B from the first time A.

[0055] The control unit 22 stores the current information acquired at time t3 and associates it with the voltage information acquired by the battery measurement device 1-1 at time t3, i.e., the voltage information received at time t4. The control unit 22 then calculates the cell resistance value from the associated current information and voltage information.

[0056] In this way, the control unit 22 obtains the current information at the time when the battery measurement device 1-1 obtains the voltage information, which is determined based on the timing when the wireless communication unit 21 transmits a voltage measurement instruction to the battery measurement device 1-1.

[0057] Specifically, the control unit 22 acquires current information a predetermined time after the reception timing of data from the battery measuring device 1-1 received from the wireless communication unit 21 in the cycle in which the wireless communication unit 21 transmits a voltage measurement instruction to the battery measuring device 1-1.

[0058] In this case, the specified time is a predetermined first time from when the wireless communication unit 21 sends a voltage measurement instruction to the battery measuring device 1-1 to when the battery measuring device 1-1 acquires voltage information minus a predetermined second time from when the wireless communication unit 21 sends a voltage measurement instruction to the battery measuring device 1-1 to when the control unit 22 receives the received data.

[0059] This allows the control unit 22 to obtain current information of the current measured by the current sensor 3 at the same time t3 as the time t3 when the voltage is measured by the battery measurement device 1-1. The control unit 22 can then calculate an accurate cell resistance of the battery cell at time t3 based on the voltage information of the voltage measured at time t3 by the battery measurement device 1-1 obtained at time t4 and the current information of the current measured by the current sensor at time t3. This allows the battery monitoring device 2 to appropriately monitor the deterioration state of the battery.

[0060] [4. Processing Executed by the Control Unit According to the First Embodiment] Next, a process executed by the control unit 22 of the battery monitoring device 2 according to the first embodiment will be described with reference to Fig. 5. Fig. 5 is an explanatory diagram showing an example of a process executed by the control unit 22 according to the first embodiment.

[0061] Here, the process in which the battery monitoring device 2 calculates the cell resistance of the battery cell whose voltage is measured by the battery measurement device 1-1 will be described, but the battery monitoring device 2 executes similar processes for the other battery measurement devices 1-2 to 1-n, so a description of the process that the battery monitoring device 2 executes for the battery measurement devices 2-1 to 1-n will be omitted.

[0062] 5, the control unit 22 first outputs a voltage measurement instruction to the wireless communication unit 21 of the battery monitoring device 2 (step S101). After that, the control unit 22 determines whether or not reception data has been received from the battery measurement device 1-1 (step S102).

[0063] If the control unit 22 determines that no data has been received from the battery measurement device 1-1 (step S102, No), it repeats the determination process of step S102 until data is received. If the control unit 22 determines that data has been received from the battery measurement device 1-1 (step S102, Yes), it acquires current information after a predetermined time has elapsed since the reception timing (step S103).

[0064] Specifically, the control unit 22 acquires from the current sensor 3 and stores current information of the current measured by the current sensor 3 at the time when the reception data from the battery measurement device 1-1 is received plus the time obtained by subtracting the second time B from the first time A. This current information corresponds to the current information acquired at time t3 in FIG.

[0065] Thereafter, the control unit 22 determines whether or not voltage information has been acquired from the battery measurement device 1-1 in response to the voltage measurement instruction for the current cycle output in step S101 (step S104). The voltage information here is the voltage information acquired at time t4 in FIG. 4. If the control unit 22 determines that the voltage information has not been acquired (step S104, No), it repeats the determination process of step S104 until the voltage information is acquired. Note that if the result in step S104 is No, the control unit 22 actually performs various processes such as sending the next command, but the description is omitted for simplification.

[0066] If the control unit 22 determines that it has acquired voltage information from the battery measurement device 1-1 (step S104, Yes), it calculates a cell resistance value from the acquired current information and voltage information (step S105) and ends the process. Then, the control unit 22 repeats the processes of steps S101 to S105, and monitors the deterioration of the battery cell whose voltage is measured by the battery measurement device 1-1 based on the sequentially calculated cell resistance values.

[0067] [5. Battery monitoring system according to the second embodiment] Fig. 6 is an explanatory diagram of a battery monitoring system 10a according to the second embodiment. As shown in Fig. 6, the battery monitoring system 10a includes a plurality of battery measurement devices 1a-1 to 1a-n (n is a natural number of 2 or more) and a battery monitoring device 2a.

[0068] The battery measurement devices 1a-1 to 1a-n differ from the wireless communication unit 12 according to the first embodiment in the operation of the wireless communication unit 12a. The battery monitoring device 2a also differs from the battery monitoring device 2 according to the first embodiment in the configuration in which the wireless communication unit 21a includes a Tx terminal 23 and in the operation of the control unit 22a.

[0069] The wireless communication unit 21a of the battery monitoring device 2a outputs a communication start signal, indicating the start of communication, from the Tx terminal 23 to the control unit 22a at the same time as transmitting a voltage measurement instruction to the battery measurement devices 1a-1 to 1a-n.

[0070] When the battery measurement devices 1a-1 to 1a-n receive a voltage measurement instruction, they transmit, to the wireless communication unit 21a of the battery monitoring device 2a, first time information indicating the detection time of the voltage information based on the timing at which the voltage measurement instruction was transmitted, and the voltage information detected at the detection time.

[0071] The control unit 22a periodically detects and stores the second time information and the current information based on the input timing of the communication start signal, and acquires the current information synchronized with the voltage information based on the first time information and the second time information. Next, a method of monitoring a battery by the battery monitoring system 10a will be described.

[0072] [6. Battery monitoring method according to the second embodiment] 7 is a timing chart showing an example of the operation of the battery monitoring system 10 according to the second embodiment. Here, the communication between the battery monitoring device 1 and the battery measurement device 1a-1 will be described as an example.

[0073] As shown in Fig. 7, the timing of data transmission and reception between the battery monitoring device 2a and the battery measurement device 1a-1 is the same as the timing of data transmission and reception shown in Fig. 4, but the operations performed inside the battery monitoring device 2a and the battery measurement device 1a-1 are different from those in the first embodiment. Therefore, here, the operations performed inside the battery monitoring device 2a and the battery measurement device 1a-1 that are different from those in the first embodiment will be described.

[0074] 7, the wireless communication unit 21a of the battery monitoring device 2a outputs a communication start signal indicating the start of communication with the battery measurement device 1a-1 from the Tx terminal 23 to the control unit 22a at the same timing as transmitting a voltage measurement instruction command to the battery measurement device 1a-1 at time t1 (step S21). As a result, the control unit 22a and the wireless communication unit 21a obtain the command transmission timing at time t1.

[0075] When the measurement unit 11 of the battery measurement device 1a-1 receives the voltage measurement instruction, it measures the voltage of the battery cell at time t3, generates voltage information, and transmits it to the wireless communication unit 12a of the battery measurement device 1a-1. The wireless communication unit 12a assigns, to the voltage information, first time information (a time stamp at the time of voltage detection) indicating time t3, which is the time when the voltage information was detected based on time t1, which is the timing when the voltage measurement instruction was transmitted (step S22).

[0076] Then, the wireless communication unit 12a transmits the first time information and the voltage information detected at the detection time to the wireless communication unit 21a of the battery monitoring device 2a. After that, the control unit 22a of the battery monitoring device 2a acquires the voltage information to which the first time information has been added at time t4.

[0077] Meanwhile, the control unit 22a of the battery monitoring device 2a periodically detects and stores second time information and current information based on time t1, which is the input timing of the communication start signal. That is, the control unit 22a obtains the current information at each timing indicated by multiple triangles in Fig. 7, and sequentially stores the information in association with the counted-up timestamp at that time.

[0078] Thereafter, when the control unit 22a acquires voltage information with a time stamp added thereto at time t4 from the battery measurement device 1a-1, it acquires current information synchronized with the voltage information based on the first time information and the second time information.

[0079] Specifically, the control unit 22a acquires, from the stored current information, current information associated with a time stamp that is the same as or closest to the time t3 of the time stamp added to the voltage information (step S23). This allows the control unit 22a to acquire synchronized current information and voltage information with the same measurement time. Therefore, the battery monitoring device 2 can calculate an accurate cell resistance value of the battery cell from the synchronized current information and voltage information, and can appropriately monitor the deterioration state of the battery.

[0080] Although the case where the control unit 22a periodically and continuously acquires the current information has been described here, this is merely an example. The control unit 22a can roughly predict a predetermined period during which the voltage will be measured by the battery measurement device 1a-1 from time t1, which is the input timing of the communication start signal, based on the information processing capability of the battery measurement device 1a-1.

[0081] Therefore, the control unit 22a may be configured to periodically detect the current information and the second time information during a predetermined period before and after the time when the battery measurement device 1a-1 is expected to acquire the voltage information (a predetermined time before and after including the time t3 shown in FIG. 7).

[0082] This allows the control unit 22a to significantly reduce the number of processes for acquiring the current information and the amount of current information stored. In this case, for example, due to a malfunction of the battery measurement device 1a-1, a situation may occur in which the time corresponding to the first time information added to the voltage information is not within the predetermined period assumed by the control unit 22a.

[0083] Therefore, when the detection time of the voltage information indicated by the first time information deviates from the expected detection time by a predetermined time or more, the control unit 22a determines that an abnormality has occurred in the battery measurement device 1a-1.

[0084] This allows the battery monitoring device 2a to not only monitor the deterioration of the battery, but also to detect an abnormality in the battery measurement device 1a-1.

[0085] [7. Processing Executed by the Control Unit According to the Second Embodiment] Next, a process executed by a control unit 22a of a battery monitoring device 2a according to the second embodiment will be described with reference to Fig. 8. Fig. 8 is an explanatory diagram showing an example of a process executed by the control unit 22a according to the second embodiment.

[0086] Here, the process in which the battery monitoring device 2a calculates the cell resistance of the battery cell whose voltage is measured by the battery measurement device 1a-1 will be described, but the battery monitoring device 2a also performs similar processes for the other battery measurement devices 1a-2 to 1a-n, and therefore a description of the processes that the battery monitoring device 2 performs for the battery measurement devices 1a-2 to 1a-n will be omitted.

[0087] 8, the control unit 22a first outputs a voltage measurement instruction (step S201), and determines whether or not a communication start signal has been input (step S202). If the control unit 22a determines that a communication start signal has not been input (step S202, No), it repeats the determination process of step S202 until a communication start signal is input.

[0088] When the control unit 22a determines that a communication start signal is input (step S202, Yes), the control unit 22a periodically detects second time information based on the input timing of the communication start signal and current information (step S203).Then, the control unit 22a stores the second time information and the current information in association with each other (step S204).

[0089] Thereafter, the control unit 22a judges whether or not it has received voltage information and first time information corresponding to the voltage measurement instruction for the current cycle output from the battery measurement device 1a-1 in step S201 (step S205). If the control unit 22a judges that it has not received the voltage information and the first time information (step S205, No), it repeats the process of step S205 until it receives the voltage information and the first time information. Note that if the result in step S205 is No, the control unit 22a actually performs various processes such as sending the next command, but the description is omitted for simplification.

[0090] When it is determined that the voltage information and the first time information have been received (Yes at step S205), the control unit 22a determines whether or not the first time information deviates from the expected time by a predetermined time or more (step S206).

[0091] When the control unit 22a determines that the first time information does not deviate from the expected time by more than a predetermined time (step S206, No), it obtains current information synchronized with the voltage information from the stored current information based on the first time information and the second time information (step S207).

[0092] Thereafter, the control unit 22a calculates the cell resistance value from the acquired current information and voltage information (step S208) and ends the process. Then, the control unit 22a repeats the processes of steps S201 to S208, and monitors the deterioration of the battery cells whose voltages are measured by the battery measurement device 1a-1 based on the sequentially calculated cell resistance values.

[0093] Furthermore, when the control unit 22a determines that the first time information deviates from the expected time by a predetermined time or more (Yes at step S206), it determines that an abnormality has occurred in the battery measurement device 1a-1 (step S209), and ends the process.

[0094] [8. Processing Executed by the Battery Measurement Device According to the Second Embodiment] Next, a process executed by the battery measurement device 1a-1 according to the second embodiment will be described with reference to Fig. 9. Fig. 9 is a flowchart showing an example of a process executed by the battery measurement device 1a-1 according to the second embodiment.

[0095] 9, the battery measurement device 1a-1 first determines whether or not a voltage measurement instruction has been received from the battery monitoring device 2a (step S301). If the battery measurement device 1a-1 determines that a voltage measurement instruction has not been received (step S301, No), it repeats the determination process of step S301 until a voltage measurement instruction is received.

[0096] If the battery measurement device 1a-1 determines that it has received the voltage measurement instruction (Yes in step S301), it acquires the voltage information (step S302).Then, the battery measurement device 1a-1 generates first time information indicating the detection time of the voltage information based on the transmission timing of the voltage measurement instruction (step S303).

[0097] Here, the battery measurement device 1a-1 regards the reception timing at which it is determined in step S301 that the voltage measurement instruction has been received as the transmission timing of the voltage measurement instruction. Note that the wireless communication unit 21a may transmit the voltage measurement instruction together with a timestamp indicating the transmission time, in which case the timestamp indicating the transmission time becomes the transmission timing of the voltage measurement instruction.

[0098] Then, the battery measurement device 1a-1 transmits the first time information and the voltage information to the battery monitoring device 2a in association with each other (step S304), and ends the process.The battery measurement device 1a-1 then starts the process again from step S301.

[0099] Further advantages and modifications may readily occur to those skilled in the art. Thus, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described above. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and equivalents thereof. [Explanation of symbols]

[0100] 10,10a Battery monitoring system 1-1~1-n, 1a-1~1a-n Battery measuring device 11 Measurement section 12, 12a Wireless communication section 2,2a Battery monitoring device 21,21a Wireless communication section 22, 22a Control section 3 Current Sensor

Claims

1. a battery measurement device for detecting voltage information of a battery; a battery monitoring device that acquires the voltage information from the battery measurement device by wireless communication and acquires current information of a current flowing through the battery from a current sensor, the battery monitoring device includes a control unit and a wireless communication unit that wirelessly communicates with the battery measurement device at a predetermined period; The wireless communication unit includes: transmitting a voltage measurement instruction to the battery measurement device and receiving data from the battery measurement device during a period in which wireless communication with the battery measurement device is established; The control unit is A timing for acquiring the current information is determined based on a timing for acquiring the data received from the battery measurement device through the wireless communication unit. Battery monitoring system.

2. The control unit is The current information is acquired after a predetermined time from a timing when the wireless communication unit receives data from the battery measurement device in a cycle in which the wireless communication unit transmits the voltage measurement instruction to the battery measurement device. The battery monitoring system of claim 1 .

3. The predetermined time is a predetermined first time from when the wireless communication unit transmits the voltage measurement instruction to the battery measurement device until when the battery measurement device acquires the voltage information, minus a predetermined second time from when the wireless communication unit transmits the voltage measurement instruction to the battery measurement device until when the control unit receives the reception data. The battery monitoring system of claim 2 .

4. A battery measurement device for detecting voltage information of a battery; a battery monitoring device that acquires the voltage information from the battery measurement device by wireless communication and acquires current information of a current flowing through the battery from a current sensor, the battery monitoring device includes a control unit and a wireless communication unit that wirelessly communicates with the battery measurement device at a predetermined period; The control unit is outputting a voltage measurement instruction from the wireless communication unit, and acquiring the current information at a time when the battery measurement device acquires voltage information based on a timing when the wireless communication unit transmits the voltage measurement instruction to the battery measurement device; The wireless communication unit includes: outputting a communication start signal indicating a start of communication to the control unit at a timing when the voltage measurement instruction is transmitted; The battery measurement device includes: when receiving the voltage measurement instruction, returning first time information indicating a detection time of the voltage information based on a timing at which the voltage measurement instruction was transmitted and the voltage information detected at the detection time to the wireless communication unit; The control unit is Second time information based on an input timing of the communication start signal and the current information are periodically detected and stored, and the current information synchronized with the voltage information is acquired based on the first time information and the second time information. Battery monitoring system.

5. The control unit is The current information and the second time information are periodically detected during a predetermined period before and after a time when the battery measurement device is expected to obtain voltage information. The battery monitoring system according to claim 4 .

6. The control unit is When the detection time of the voltage information indicated by the first time information deviates from the expected detection time by a predetermined time or more, it is determined that an abnormality has occurred in the battery measurement device. The battery monitoring system according to claim 4 or 5.

7. a wireless communication unit that wirelessly communicates with a battery measurement device that detects battery voltage information at a predetermined period; a control unit that acquires the voltage information received from the battery measurement device by wireless communication using the wireless communication unit, and acquires current information of a current flowing through the battery from a current sensor; Equipped with The wireless communication unit includes: transmitting a voltage measurement instruction to the battery measurement device and receiving data from the battery measurement device during a period in which wireless communication with the battery measurement device is established; The control unit is A timing for acquiring the current information is determined based on a timing for acquiring the data received from the battery measurement device through the wireless communication unit. Battery monitoring device.

8. A wireless communication unit that performs wireless communication at a predetermined period with a battery measurement device that detects battery voltage information; a control unit that acquires the voltage information received from the battery measurement device by wireless communication using the wireless communication unit, and acquires current information of a current flowing through the battery from a current sensor; Equipped with The control unit is outputting a voltage measurement instruction from the wireless communication unit, and acquiring the current information at a time when the battery measurement device acquires the voltage information based on a timing when the wireless communication unit transmits the voltage measurement instruction to the battery measurement device; The wireless communication unit includes: outputting a communication start signal indicating a start of communication to the control unit at a timing when the voltage measurement instruction is transmitted; The battery measurement device includes: when receiving the voltage measurement instruction, returning first time information indicating a detection time of the voltage information based on a timing at which the voltage measurement instruction was transmitted and the voltage information detected at the detection time to the wireless communication unit; The control unit is Second time information based on an input timing of the communication start signal and the current information are periodically detected and stored, and the current information synchronized with the voltage information is acquired based on the first time information and the second time information. Battery monitoring device.

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