Battery device

Abstract

The storage battery device of the embodiment provides a storage battery device with high reliability for performing electric wave-based communication, which includes a plurality of battery modules, each of which includes a battery pack including a plurality of battery cells, and a battery monitoring unit that measures the voltage of the battery cells and the temperature of at least one location of the battery pack, and a battery management unit that performs electric wave-based communication with the plurality of battery monitoring units, periodically receives measured values of the voltage of the battery cells and the temperature of the battery pack, and when it is determined that communication with the plurality of battery monitoring units is disturbed, extends the communication cycle with the battery monitoring unit, sets values of the chargeable current and the dischargeable current of the battery pack corresponding to at least the communication cycle, and notifies the set values to a higher-level device.

Description

TECHNICAL FIELD

[0001] The present application relates to a battery device. BACKGROUND

[0002] A battery device that combines a plurality of battery modules is utilized in various uses. In recent years, in order to simplify the structure of the battery device, research has been conducted to wireless the communication between the battery modules and the management device by radio waves.

[0003] On the other hand, radio wave-based wireless communication is likely to malfunction due to interference, and therefore, in the past, a scheme has been proposed to ensure the reliability of communication by measures such as providing a plurality of transmission units.

[0004] However, when radio communication is performed, it is not possible to completely eliminate the possibility of malfunction due to interference, and therefore, a countermeasure is desired to make the battery device operate even in the case of being interfered with and to improve the usability of the battery device.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT DOCUMENTS

[0007] Patent Document 1: International Publication No. 2014 / 103008

[0008] Patent Document 2: Japanese Patent Application Publication No. 2018-81837

[0009] Patent Document 3: International Publication No. 2015 / 189898 SUMMARY

[0010] The embodiment of the present application is made in view of the above circumstances, and aims to provide a battery device that is high in reliability of communication based on radio waves.

[0011] The battery device of the embodiment has a plurality of battery modules that have a battery pack including a plurality of battery cells, and a battery monitoring unit that measures the voltage of the battery cells and the temperature of at least one of the battery packs, and a battery management unit that performs radio wave-based communication with a plurality of the battery monitoring units, periodically receives the measured values of the voltage of the battery cells and the temperature of the battery packs, and when it is determined that the communication with the plurality of battery monitoring units is interfered with, extends the communication cycle with the battery monitoring unit, and sets the value of the chargeable current and the value of the dischargeable current of the battery pack corresponding to at least the communication cycle, and notifies the set values to a higher-level device. BRIEF DESCRIPTION OF DRAWINGS

[0012] Figure 1FIG. 1 is a diagram schematically showing a configuration example of a battery device of one embodiment.

[0013] Figure 2 FIG. 2 is a diagram for explaining an example of the operation of the battery device of one embodiment.

[0014] Figure 3 FIG. 3 is a flowchart for explaining an example of the operation of the battery management unit in the battery device of one embodiment.

[0015] Figure 4A FIG. 4 is a diagram showing an example of the values of the chargeable current and the dischargeable current corresponding to the communication cycle of the battery monitoring unit and the battery management unit, the SOC and the SOH of the battery pack, and the temperature of the battery pack.

[0016] Figure 4B FIG. 5 is a diagram showing an example of the values of the chargeable current and the dischargeable current corresponding to the communication cycle of the battery monitoring unit and the battery management unit, the SOC and the SOH of the battery pack, and the temperature of the battery pack.

[0017] Figure 4C FIG. 6 is a diagram showing an example of the values of the chargeable current and the dischargeable current corresponding to the communication cycle of the battery monitoring unit and the battery management unit, the SOC and the SOH of the battery pack, and the temperature of the battery pack.

[0018] Figure 4D FIG. 7 is a diagram showing an example of the values of the chargeable current and the dischargeable current corresponding to the communication cycle of the battery monitoring unit and the battery management unit, the SOC and the SOH of the battery pack, and the temperature of the battery pack.

[0019] Figure 5A FIG. 8 is a diagram showing an example of the values of the chargeable current and the dischargeable current corresponding to the communication cycle of the battery monitoring unit and the battery management unit, the SOC and the SOH of the battery pack, and the temperature of the battery pack.

[0020] Figure 5B FIG. 9 is a diagram showing an example of the values of the chargeable current and the dischargeable current corresponding to the communication cycle of the battery monitoring unit and the battery management unit, the SOC and the SOH of the battery pack, and the temperature of the battery pack.

[0021] Figure 6 FIG. 10 is a diagram for explaining an example of the manner of wireless communication between the battery monitoring unit and the battery management unit.

[0022] Figure 7 FIG. 11 is a diagram for explaining an example of the manner of wireless communication between the battery monitoring unit and the battery management unit in the battery device of the second embodiment.

[0023] Figure 8FIG. 2 is a flowchart for explaining another example of the operation of the battery management unit in the battery device of one embodiment. DETAILED DESCRIPTION

[0024] Hereinafter, one configuration example of the battery device of the first embodiment will be described in detail with reference to the drawings.

[0025] Figure 1 FIG. 1 is a diagram schematically showing a configuration example of the battery device of one embodiment.

[0026] The battery device of the present embodiment is provided with a plurality of battery modules MDL, a battery management unit (BMU) 20, a current sensor SS, an electromagnetic contactor CP, CN.

[0027] The battery module MDL is provided with a battery pack BT including a plurality of battery cells (not shown) and a cell monitoring unit (CMU) 10.

[0028] The battery pack BT is provided with, for example, a plurality of battery cells of lithium ion batteries connected in series or in parallel.

[0029] The cell monitoring unit 10 is provided with a measurement circuit that detects the voltage of each of the plurality of battery cells and the temperature of at least one point of the battery pack BT, and a wireless transceiver circuit (not shown) that enables wireless communication based on electric waves with the battery management unit 20, and the cell monitoring unit 10 is capable of periodically transmitting the measurement values to the battery management unit 20.

[0030] In addition, the cell monitoring unit 10 performs equalization of the voltages of the plurality of battery cells (cell balancing) based on a control signal received from the battery management unit 20.

[0031] The cell monitoring unit 10 can be configured by hardware, by software, or by a combination of hardware and software, for example. The cell monitoring unit 10 is, for example, a circuit provided with at least one processor such as a CPU, an MPU, and a memory in which a program executed by the processor is recorded, and the above-described operation is realized by software.

[0032] The battery device of the present embodiment sets the voltage between the main circuit on the high potential side and the main circuit on the low potential side at 10 kV by connecting 300 battery cells in total in series by connecting the plurality of battery modules MDL in series.

[0033] The current sensor SS detects the value of the current flowing in the main circuit on the high potential side and supplies the detected value to the battery management unit 20.

[0034] An electromagnetic contactor CN is present on a main circuit connecting a terminal on the lowest potential side of the plurality of battery modules MDL and a negative terminal, and is capable of switching the electrical connection between the plurality of battery modules MDL and the negative terminal. The electromagnetic contactor CN controls the opening and closing of the contact points in accordance with a control signal from the battery management unit 20.

[0035] An electromagnetic contactor CP is present on a main circuit connecting a terminal on the highest potential side of the plurality of battery modules MDL and a positive terminal, and is capable of switching the electrical connection between the plurality of battery modules MDL and the positive terminal. The electromagnetic contactor CP controls the opening and closing of the contact points in accordance with a control signal from the battery management unit 20.

[0036] The battery management unit 20 is capable of communicating with the plurality of battery monitoring units 10 and a higher-level control circuit (not shown). Furthermore, in the battery device of the present embodiment, the battery management unit 20 is provided with a communication circuit capable of wireless communication based on electric waves with the plurality of battery monitoring units 10 and wired communication with the higher-level control circuit.

[0037] The battery management unit 20 is capable of receiving various control signals from the higher-level control circuit and controlling the operation of the plurality of battery monitoring units 10 and the electromagnetic contactors CN, CP based on the received information.

[0038] The battery management unit 20 periodically receives the detected values of the voltage of the plurality of battery cells (or battery groups BT) and the detected values of the temperature of the battery groups BT from the plurality of battery monitoring units 10, respectively, and periodically receives the detected value of the current flowing from the current sensor SS to the plurality of battery groups BT. The battery management unit 20 is capable of calculating the state of charge (SOC) and the state of health (SOH) of the battery groups BT (or battery cells) based on the received values. The SOC of the battery group BT is, for example, the ratio of the current capacity [Ah] of the battery group BT to the capacity [Ah] of the battery group BT at the time of full charge (= (current capacity / capacity at the time of full charge) x 100). The SOH of the battery group BT is, for example, the ratio of the current capacity [Ah] of the battery group BT at the time of full charge to the initial value [Ah] of the capacity at the time of full charge of the battery group BT (= (initial value of the capacity at the time of full charge / current capacity at the time of full charge) x 100).

[0039] The battery management unit 20 monitors the voltage of the plurality of battery cells and the current flowing through the plurality of battery groups BT, and controls the battery monitoring units 10 to equalize the voltage of the plurality of battery cells. The battery management unit 20, for example, controls the operation of the battery system so that the battery cells do not become abnormal states such as overcharging, overdischarging, and the like.

[0040] The battery management unit 20 can be constituted by hardware, software, or a combination of hardware and software. The battery management unit 20 can include, for example, at least one processor and a memory in which a program executed by the processor is recorded.

[0041] Next, an example of the operation of the battery device according to the present embodiment will be described.

[0042] Figure 2 FIG. 1 is a diagram for explaining an example of the operation of the battery device according to one embodiment.

[0043] The battery management unit 20 transmits an output instruction of data of measured values and a cell balancing instruction to the plurality of battery monitoring units 10 when receiving an operation permission notification or a stop notification from the host device (step SA1).

[0044] Further, the battery management unit 20 can transmit the output instruction of data and the cell balancing instruction to the plurality of battery monitoring units 10, or can sequentially transmit the instructions to the plurality of battery monitoring units 10 at different timings.

[0045] The battery monitoring unit 10 measures the voltage of the plurality of battery cells and the temperature at at least one point of the battery pack BT when receiving the output instruction of data and the cell balancing instruction from the battery management unit 20 (step SA3), and transmits the measured values to the battery management unit 20 (step SA4).

[0046] The battery management unit 20 and the battery monitoring unit 10 repeatedly perform the above-described steps SA2 to SA4. That is, the battery management unit 20 transmits the output instruction of data and the cell balancing instruction to the plurality of battery monitoring units 10 based on the received voltage values when receiving the measured values of the voltage and the measured values of the temperature from the battery monitoring unit 10 (step SA2). Further, in the present embodiment, a period from when the battery management unit 20 performs the step SA2 to when the battery management unit 20 performs the step SA2 next is regarded as a communication cycle of the battery management unit 20 and the battery monitoring unit 10.

[0047] Next, the battery monitoring unit 10 updates the state of the cell balancing circuit (not shown) in such a manner that the equalization of the voltage of the plurality of battery cells is performed in accordance with the cell balancing instruction received from the battery management unit 20 (step SA5). For example, the battery monitoring unit 10 switches the switching elements of the cell balancing circuit (not shown) in accordance with the cell balancing instruction received from the battery management unit 20 so as to discharge the battery cell having a large voltage difference from the other battery cells.

[0048] The battery management unit 20 receives the detected value of the current flowing from the current sensor SS to the main circuit on the high potential side after receiving the measured values of the voltage and the temperature from the plurality of battery monitoring units 10 (step SA6).

[0049] In addition, in Figure 2 In the example shown, the battery management unit 20 receives the measured value of the current from the current sensor SS after receiving the measured values of the voltage and the temperature from the battery monitoring unit 10, but the order of the above actions can be reversed, or the actions of receiving the measured values of the voltage and the temperature from the battery monitoring unit 10 and receiving the measured value of the current from the current sensor SS can be performed in parallel.

[0050] Next, the battery management unit 20 performs an operation for setting the communication period with the battery monitoring unit 10 and the allowable current (chargeable current and dischargeable current) of the battery pack BT based on the values of the voltage and the temperature received from the battery monitoring unit 10 and the value received from the current sensor SS (step SA7).

[0051] In the present embodiment, the battery management unit 20 determines whether a failure caused by interference has occurred when communicating with the plurality of battery monitoring units 10, and extends the communication period with the battery monitoring unit 10 when interference is received. The battery management unit 20, for example, extends the communication period with the battery monitoring unit 10 when the number of retransmissions caused by communication failure reaches a predetermined number or more within a predetermined period.

[0052] At this time, the battery management unit 20 sets the values of the chargeable current and the dischargeable current based on the communication period, the SOC, the SOH of the battery pack BT, and the temperature of the battery pack BT, and notifies the device (for example, the host device) that charges and discharges the battery pack BT of the set values. In addition, the battery management unit 20 determines whether to permit charging and discharging of the battery pack BT, and notifies whether to permit charging and discharging together with the values of the chargeable current and the dischargeable current (step SA8).

[0053] Figure 3 is a flowchart for explaining an example of the operation of the battery management unit in the storage battery device of one embodiment. Here, an example of the operation of the battery management unit 20 in the above step SA8 is explained.

[0054] The battery management unit 20 counts the number of retransmissions as a result of attempts at communication between the battery management unit 20 and the plurality of battery monitoring units 10 within a predetermined period (step SB1), and determines whether the counted value exceeds a predetermined threshold value (step SB2).

[0055] The battery management unit 20 shortens the communication cycle with the battery monitoring unit 10 when the count value is below a prescribed threshold value. That is, the battery management unit 20 shortens the communication cycle by one stage within a range between a standard value and a lower limit value in a manner that the number of communications in a prescribed period increases. The battery management unit 20 can change the communication cycle stage by stage within a range above the lower limit value and below an upper limit value. Further, the time span of one stage at which the battery management unit 20 extends or shortens the communication cycle stage by stage can be adjusted in accordance with the SOC, temperature, and the like of the battery pack BT. At this time, in a case where the communication cycle with the battery monitoring unit 10 is set to a prescribed standard value, the battery management unit 20 does not change the communication cycle (step SB4).

[0056] The battery management unit 20 extends the communication cycle with the battery monitoring unit 10 when it is determined in step SB2 that the count value exceeds a prescribed threshold value. That is, the battery management unit 20 extends the communication cycle by one stage within a range between a standard value and an upper limit value in a manner that the number of communications in a prescribed period decreases (step SB3).

[0057] The battery management unit 20 sets the value of the chargeable current and the value of the dischargeable current of the battery pack BT using the communication cycle with the battery monitoring unit 10 after step SB3 and step SB4 (step SB5).

[0058] In the storage battery device of the present embodiment, the communication cycle (standard value) at normal times (when no communication failure occurs) is set to, for example, 0.1 seconds, and the upper limit value of the communication cycle is set to, for example, 1 second. The battery management unit 20 extends the communication cycle from 0.1 seconds to, for example, 0.5 seconds in a case where it is determined in step SB2 that the count value exceeds a prescribed threshold value when the currently set communication cycle is 0.1 seconds.

[0059] Further, the battery management unit 20 can, in a case where it is determined in step SB2 that the count value exceeds a prescribed threshold value when the currently set communication cycle is 1 second, not extend the communication cycle, but notify the upper level device so as to prohibit charging and discharging.

[0060] Figures 4A-4D is a graph showing an example of the values of the chargeable current and the dischargeable current corresponding to the communication cycle with the battery monitoring unit and the battery management unit, the SOC and SOH of the battery pack, and the temperature of the battery pack. Here, an example of the values of the chargeable current and the dischargeable current of the battery pack BT is shown when the SOH of the battery pack BT is above a prescribed threshold value (the degree of deterioration is small).

[0061] Figure 4Aa value of a chargeable current corresponding to the communication period and the SOC of the battery group BT when the SOH of the battery group BT is above a prescribed threshold and the temperature of the battery group BT is 25°C.

[0062] Figure 4B a value of a dischargeable current corresponding to the communication period and the SOC of the battery group BT when the SOH of the battery group BT is above a prescribed threshold and the temperature of the battery group BT is 25°C.

[0063] Figure 4C a value of a chargeable current corresponding to the communication period and the SOC of the battery group BT when the SOH of the battery group BT is above a prescribed threshold and the temperature of the battery group BT is -30°C.

[0064] Figure 4D a value of a dischargeable current corresponding to the communication period and the SOC of the battery group BT when the SOH of the battery group BT is above a prescribed threshold and the temperature of the battery group BT is -30°C.

[0065] The battery management unit 20 can also have, for example, a plurality of tables that store values of a chargeable current and a dischargeable current corresponding to the SOC and SOH of the battery group BT, the temperature of the battery group BT, and the communication period as illustrated in FIGS. 9A and 9B. Figures 4A-4D At this time, the battery management unit 20 can select a corresponding table according to the SOH and temperature of the battery group BT and calculate a value of a chargeable current and a value of a dischargeable current corresponding to the communication period and the SOC of the battery group BT. The battery management unit 20 need not have a table corresponding to a continuous value of the temperature of the battery group BT and can correct an error of a calculated value using a table corresponding to a value closest to the temperature of the battery group BT to calculate a value of a chargeable current and a value of a dischargeable current.

[0066] The battery management unit 20 can calculate the SOH of a plurality of battery groups BT based on the measured values of voltage and temperature received from a plurality of battery monitoring units 10 and the value of current received from the current sensor SS, for example. In a case where the SOH of a plurality of battery groups BT is biased, the battery management unit 20 can use a value of a chargeable current and a value of a dischargeable current corresponding to the SOH, temperature, SOC, and communication period of a battery group BT having the largest degree of deterioration as a value of a plurality of battery groups BT.

[0067] For example, the communication period is reduced from 0.1 seconds to 0.5 seconds to reduce the number of communications per unit time, and the battery management unit 20 can calculate a value of a chargeable current corresponding to the communication period and the SOC of the battery group BT when the SOH of the battery group BT is above a prescribed threshold and the temperature of the battery group BT is 25°C according to Figure 4A and Figure 4BThe relationship between the SOC of the battery pack BT and the communication cycle is shown, and the values ​​of the rechargeable current and the discharge current are calculated. Based on... Figure 4A as well as Figure 4B With a communication cycle of 0.5 seconds, the rechargeable current is 3It[A] and the discharge current is 3It[A] across the entire SOC region of the battery pack BT. Additionally, It[A] is the rated current per unit time [Ah / h].

[0068] For example, when the communication cycle is reduced from 0.1 seconds to 1 second, thus decreasing the number of communications per unit time, and the state of harmonics (SOH) of multiple battery packs (BTs) is above a specified threshold, and the temperature of the battery packs (BTs) is -30°C, the battery management unit 20 can, according to... Figure 4C as well as Figure 4D The relationship between the SOC of the battery pack BT and the communication cycle is shown, and the values ​​of the rechargeable current and the discharge current are calculated. Based on... Figure 4C With a communication cycle of 1 second, the rechargeable current is 1It[A] when the SOC of the battery pack BT is above 50%, and the rechargeable current is 3It[A] when the SOC of the battery pack BT is less than 50%. According to... Figure 4D When the communication cycle is 1 second, the discharge current is 3It[A] when the SOC of the battery pack BT is above 10%, and the discharge current is 1It[A] when the SOC of the battery pack BT is less than 10%.

[0069] When the SOH of the battery pack BT is less than a specified threshold, the battery management unit 20 can calculate the rechargeable current and discharge current of the battery pack BT based on the temperature, SOC and communication cycle of the battery pack BT.

[0070] Figure 5A as well as Figure 5B This is a diagram illustrating an example of the communication cycle with the battery monitoring unit and battery management unit, the SOC and SOH of the battery pack, the rechargeable current corresponding to the temperature of the battery pack, and the values ​​of the dischargeable current.

[0071] Figure 5A This represents the rechargeable current value corresponding to the communication cycle and the SOC of the battery pack BT when the SOH of the battery pack BT is less than a specified threshold and the temperature of the battery pack BT is 25°C.

[0072] Figure 5B This represents the discharge current value corresponding to the communication cycle and the SOC of the battery pack BT when the SOH of the battery pack BT is less than a specified threshold and the temperature of the battery pack BT is 25°C.

[0073] Similar to when the SOH of the battery pack BT is above a specified threshold, the battery management unit 20 may also have multiple tables, which store information about the battery pack. Figure 5A as well asFigure 5B The values of the chargeable current and the dischargeable current corresponding to the SOC and SOH of the battery pack BT, the temperature of the battery pack BT, and the communication cycle are shown. At this time, the battery management unit 20 can select a corresponding table according to the SOH and the temperature of the battery pack BT, and calculate the values of the chargeable current and the dischargeable current corresponding to the communication cycle and the SOC of the battery pack BT.

[0074] For example, the communication cycle is set to 0.5 seconds from 0.1 seconds to reduce the number of communications per unit time, and when the SOH of the plurality of battery packs BT is less than a prescribed threshold value and the temperature of the battery pack BT is 25°C, the battery management unit 20 can calculate the values of the chargeable current and the dischargeable current according to the relationship between the SOC of the battery pack BT and the communication cycle shown in FIG. 9. Figure 5A Figure 5B The values of the chargeable current and the dischargeable current are calculated according to the relationship between the SOC of the battery pack BT and the communication cycle shown in FIG. 9. According to the relationship between the SOC of the battery pack BT and the communication cycle shown in FIG. 9, when the communication cycle is 0.5 seconds, the chargeable current is 1 It [A] when the SOC of the battery pack BT is 80% or more, and the chargeable current is 3 It [A] when the SOC of the battery pack BT is less than 80%. Figure 5A Figure 5B According to the relationship between the SOC of the battery pack BT and the communication cycle shown in FIG. 9, when the communication cycle is 0.5 seconds, the dischargeable current is 3 It [A] when the SOC of the battery pack BT is 15% or more, and the dischargeable current is 1 It [A] when the SOC of the battery pack BT is less than 15%.

[0075] The battery management unit 20 notifies the host device of the values of the chargeable current and the dischargeable current calculated as described above (step SB6).

[0076] Next, the battery management unit 20 acquires the current value from the current sensor SS (step SB7). At this time, the battery management unit 20 acquires the current value from the current sensor SS at a prescribed sampling rate for a prescribed period.

[0077] The battery management unit 20 determines whether the discharge current of the battery pack BT has continuously exceeded a limit value (discharge current limit value) for a prescribed period based on the current value acquired from the current sensor SS for the prescribed period (step SB8). At this time, the limit value of the discharge current is an upper limit value of the current that can be safely discharged continuously, and can be the same as the value of the dischargeable current.

[0078] When the value of the discharge current has not continuously exceeded the limit value for the prescribed period, the battery management unit 20 notifies the host device of the intention to permit discharging (step SB9).

[0079] When the value of the discharge current has continuously exceeded the limit value for the prescribed period, the battery management unit 20 notifies the host device of the request to stop discharging (step SB10).

[0080] ​​Further, the battery management unit 20 determines whether the charging current of the battery pack BT exceeds a limit value (charging current limit value) for a prescribed period based on the current value obtained from the current sensor SS for the prescribed period (step SB11). At this time, the limit value for the charging current is an upper limit value of the current for which charging can be continuously performed safely, and can be the same as the value of the chargeable current.

[0081] When the value of the charging current does not exceed the limit value for the prescribed period, the battery management unit 20 notifies the upper-level device of the intention to permit charging (step SB12).

[0082] When the value of the charging current exceeds the limit value for the prescribed period, the battery management unit 20 notifies the upper-level device of the request to stop charging (step SB13).

[0083] As described above, in the case where the upper-level device performs charging or discharging of the battery pack BT without detaching the charging current limit value or the discharging current limit value, the safety of the battery device cannot be ensured, and therefore the battery management unit 20 requests the upper-level device to stop charging or discharging (or both charging and discharging) of the battery pack BT. Thus, the safety of the battery device can be ensured. Further, when the SOC of the battery pack BT is high, the battery management unit 20 does not need to make the request to stop discharging of the battery pack BT. In addition, when the SOC of the battery pack BT is low, the battery management unit 20 does not need to make the request to stop charging of the battery pack BT. The battery management unit 20 improves the usability of the battery device by making the determination corresponding to the value of the SOC of the battery pack BT at the time of charging and at the time of discharging of the battery pack BT, respectively.

[0084] As described above, in the battery device of the present embodiment, when the communication state is poor, the frequency of communication between the battery management unit 20 and the battery monitoring unit 10 is reduced, and therefore the measured values of the voltage of the battery cell and the measured value of the temperature of the battery pack BT are not continuously received.

[0085] For example, in the case where the battery management unit 20 cannot monitor the voltage and the temperature of the battery pack BT due to a communication failure for a prescribed period, the battery device can stop even if the battery pack BT is normal. If the battery device stops, the power supply to the load device is stopped, and therefore this is one cause of reduction in reliability of the battery device.

[0086] In contrast, in the battery device of the present embodiment, when the battery pack BT is normal, in the case where the communication between the battery management unit 20 and the battery monitoring unit 10 becomes temporarily difficult due to a communication failure, the battery device is prevented from stopping, and the reliability of the battery device is ensured.

[0087] That is, according to the storage battery device of the present embodiment, a storage battery device with high reliability of communication based on electric waves can be provided.

[0088] Next, the storage battery device of the second embodiment will be described in detail with reference to the drawings.

[0089] In the storage battery device of the present embodiment, wireless communication based on electric waves is performed between the battery management unit 20 and the battery monitoring unit 10, as in the above-described first embodiment, but differs from the above-described first embodiment in that a communication method of switching a plurality of channels is employed.

[0090] Figure 6 is a diagram for illustrating an example of a method of wireless communication performed between the battery monitoring unit and the battery management unit.

[0091] In the storage battery device of the present embodiment, wireless communication based on a communication method (for example, Bluetooth (registered trademark)) of switching a plurality of channels by frequency hopping (FH) or the like is performed between the battery management unit 20 and the battery monitoring unit 10.

[0092] In this example, one channel is shared by a plurality of battery monitoring units 10. In Figure 6 In FIG. 10, an example of a channel used by a first module group MDL1 including a plurality of battery monitoring units 10 and a channel used by a second module group MDL2 including other plurality of battery monitoring units 10 is represented in time series. In addition, in FIG. 10, the density in the frequency direction represents the strength of electromagnetic waves. A portion displayed more densely represents that the electromagnetic waves are strong, and a portion displayed more sparsely represents that the electromagnetic waves are weak. Figure 6

[0093] Figure 6 The region CHA shown in FIG. 9 is a frequency band of electromagnetic waves with a large influence of interfering waves. If a channel overlapping the region CHA is used, it is difficult to perform communication due to communication failure.

[0094] Figure 7 is a diagram for illustrating an example of a method of wireless communication performed between the battery monitoring unit and the battery management unit in the storage battery device of the second embodiment.

[0095] In order to avoid communication failure due to interfering waves as described above, in the storage battery device of the present embodiment, in communication between the battery management unit 20 and a plurality of battery monitoring units 10, a channel overlapping the region CHA is skipped and used. In this case, it is possible to avoid the influence due to interfering waves, on the other hand, a plurality of module groups MDL1, MDL2 perform communication using a limited channel, and it is likely that communication congestion cannot be established.

[0096] ​Therefore, in the storage battery device of the present embodiment, when the number of channels that cannot be used due to the interfering wave exceeds the prescribed threshold value, the battery management unit 20 extends the communication cycle with the battery monitoring unit 10 (reduces the number of communications per unit time), sets the value of the chargeable current and the value of the dischargeable current corresponding to the communication cycle, and limits the charge and discharge currents.

[0097] Next, an example of the operation of the battery management unit of the storage battery device of the present embodiment will be described.

[0098] Figure 8 is a flowchart for explaining another example of the operation of the battery management unit in the storage battery device of one embodiment. Here, an example of the operation of the above step SA8 of the battery management unit 20 in the storage battery device of the above first embodiment will be described.

[0099] The battery management unit 20 acquires information on the number of channels that cannot be used due to the interfering wave (step SC1), and determines whether the number of channels that cannot be used exceeds the prescribed threshold value (step SC2).

[0100] When the number of channels that cannot be used is equal to or less than the prescribed threshold value, the battery management unit 20 sets the chargeable current and the dischargeable current of the battery pack BT to the rated maximum value, and transmits the set values to the higher-level device (step SC3).

[0101] Next, the battery management unit 20 sets the communication cycle with the battery monitoring unit 10 to the value in the normal time (the prescribed standard value) (step SC4). In the present embodiment, the value of the communication cycle with the battery monitoring unit 10 in the normal time is 0.1 seconds.

[0102] When it is determined in step SC2 that the number of channels that cannot be used exceeds the prescribed threshold value, the battery management unit 20, for example, similarly to step SB5 of the above first embodiment, extends the communication cycle with the battery monitoring unit 10, and sets the values of the chargeable current and the dischargeable current in accordance with the communication cycle, the SOC and the SOH of the battery pack BT, and the temperature of the battery pack BT (step SC5).

[0103] Steps SC6 to SC13 are the same as steps SB6 to SB13 of the above first embodiment.

[0104] As described above, in the storage battery device of the present embodiment, when the communication state is poor, by reducing the frequency of communication between the battery management unit 20 and the battery monitoring unit 10, it is possible to avoid congestion of communication in the channels that can be used, and to avoid failure to receive the measured value of the temperature of the battery pack BT.

[0105] That is, according to the battery device of the present embodiment, a battery device with high reliability of communication based on electric waves can be provided.

[0106] The embodiments of the present application have been described, but these embodiments are presented as examples and are not intended to limit the scope of the application. These new embodiments can be implemented in other various ways, and various omissions, substitutions, and changes can be made within the scope of the gist of the application. These embodiments and modifications thereof are included in the scope or gist of the application, and are also included in the scope of the application and equivalents thereof recited in the claims.

Claims

1. A battery device comprising: a plurality of battery modules each including a battery pack including a plurality of battery cells and a battery monitoring unit that measures a voltage of the battery cells and a temperature at at least one location of the battery pack; a current sensor that detects a current flowing through the plurality of battery packs; and a battery management unit that performs communication with the plurality of battery monitoring units based on electric waves, periodically receives measured values of the voltage of the battery cells and the temperature of the battery pack, and performs communication with the current sensor using wired communication, receives a detection value from the current sensor, counts a number of times of retransmission caused by a failure of the communication with the plurality of battery monitoring units, determines that the communication with the plurality of battery monitoring units is interfered with when the number of times of retransmission in a prescribed period exceeds a prescribed threshold value, lengthens a communication period with the battery monitoring unit on a stage-by-stage basis when it is determined that the communication with the plurality of battery monitoring units is interfered with, sets values of a chargeable current and a dischargeable current of the battery pack corresponding to the communication period, SOH and SOC of the battery pack, and the temperature at at least one location of the battery pack, and notifies the set values to a higher-level device.

2. A battery device comprising: a plurality of battery modules each including a battery pack including a plurality of battery cells and a battery monitoring unit that measures a voltage of the battery cells and a temperature at at least one location of the battery pack; a current sensor that detects a current flowing through the plurality of battery packs; and a battery management unit that performs communication with the plurality of battery monitoring units based on electric waves, periodically receives measured values of the voltage of the battery cells and the temperature of the battery pack, and performs communication with the current sensor using wired communication, receives a detection value from the current sensor, performs the communication based on a manner of switching a plurality of channels between the plurality of battery monitoring units, determines that the communication with the plurality of battery monitoring units is interfered with when a number of channels that cannot be used for the communication due to interference exceeds a prescribed threshold value, lengthens a communication period with the battery monitoring unit on a stage-by-stage basis when it is determined that the communication with the plurality of battery monitoring units is interfered with, sets values of a chargeable current and a dischargeable current of the battery pack corresponding to the communication period, SOH and SOC of the battery pack, and the temperature at at least one location of the battery pack, and notifies the set values to a higher-level device.

3. The battery device according to claim 1 or 2, wherein the battery management unit acquires a value of the current detected by the current sensor, transmits a request to stop charging of the battery pack to the higher-level device when a value of a charging current of the battery pack exceeds a charging current limit value continuously for a prescribed period, and transmits a request to stop discharging of the battery pack to the higher-level device when a value of a discharging current of the battery pack exceeds a discharging current limit value continuously for a prescribed period. ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​ ​

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