Battery monitoring device

Abstract

To provide a battery monitoring device that can ensure the reliability of a precipitation amount detection unit that calculates the amount of lithium precipitation.SOLUTION: A battery monitoring device 20 monitors the amount of lithium precipitation in a lithium ion battery. The battery monitoring device 20 comprises: a storage unit 51 that stores a change over time of the amount of lithium precipitation as one of the histories of use of the lithium ion battery or one of the histories of manufacture of the lithium ion battery; and an abnormality identification unit 544 that, when an abnormality occurs in the lithium ion battery, identifies the cause of occurrence of the abnormality on the basis of the use history and the manufacture history.SELECTED DRAWING: Figure 24

Description

Technical Field

[0001] The present disclosure relates to a battery monitoring device.

Background Art

[0002] Conventionally, as a technique for diagnosing an internal short circuit of a lithium-ion battery, there is known one including a short-circuit circuit including a switch, a resistor, a coil, etc. that short-circuit both ends of the lithium-ion battery (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] By the way, the inventors of the present invention focused on the fact that there is a correlation between the amount of lithium precipitation in a lithium-ion battery and the behavior of current and voltage when both ends of the lithium-ion battery are short-circuited, and considered estimating the amount of lithium precipitation from the behavior.

[0005] However, the internal resistance of a lithium-ion battery is about several mΩ to several hundred mΩ, and it is easily affected by disturbances. It was found that it is difficult to accurately obtain the amount of lithium precipitation by the above estimation method and that it lacks reliability. This was found as a result of the inventors' intensive studies.

[0006] One object of the present disclosure is to provide a battery monitoring device capable of ensuring the reliability of a precipitation amount detection unit that calculates the amount of lithium precipitation. Another object of the present disclosure is to provide a battery monitoring device capable of appropriately detecting the amount of lithium precipitation.

Means for Solving the Problems

[0007] The invention according to claim 1 is a battery monitoring device for monitoring the amount of lithium precipitation in a lithium-ion battery, a precipitation amount detection unit (37) that calculates the amount of lithium precipitation using the output of a sensor installed in a storage battery, a storage unit (51) that stores the temporal change in the amount of lithium precipitation as one of the usage histories or one of the manufacturing histories of the lithium-ion battery, and an abnormality identification unit (544) that identifies the cause of an abnormality based on the usage history and the manufacturing history when an abnormality occurs in the lithium-ion battery.

[0008] With this configuration, it is possible to appropriately detect the amount of lithium precipitation non-destructively and in a short time, and to perform an inspection of the lithium precipitation state. In particular, since a sensor for detecting lithium precipitation is installed in the storage battery, it is possible to detect the lithium precipitation state regardless of time and location. Furthermore, by storing the temporal change in the amount of lithium precipitation in the storage unit as one of the usage histories or one of the manufacturing histories of the lithium-ion battery, it is possible to clearly grasp when lithium has precipitated. This has the advantage of clarifying the responsibility for lithium precipitation.

[0009] The invention according to claim 2 is When the amount of lithium precipitation increases beyond a predetermined threshold value, the storage battery is heated by a heating element (HM) that raises the temperature of the storage battery.

[0010] According to this, the lithium-ion battery is heated at the timing when the amount of lithium precipitation increases, and the increase in the amount of lithium precipitation is appropriately suppressed, so that the lithium-ion battery can be used in a safe and highly efficient manner.

[0011] Note that the reference numerals in parentheses attached to each component etc. indicate an example of the correspondence relationship between the component etc. and the specific components etc. described in the embodiments described later.

Brief Description of the Drawings

[0012]

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Embodiments for Carrying Out the Invention

[0013] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, parts that are the same as or equivalent to those described in the preceding embodiments may be given the same reference numerals, and the description thereof may be omitted. Further, in the embodiments, when only a part of the components is described, the components described in the preceding embodiments can be applied to the other parts of the components. The following embodiments can be partially combined with each other as long as there is no problem in the combination, even if not particularly specified. (First Embodiment) In this embodiment, first, an example in which the battery monitoring device 20 and the battery monitoring method of the present disclosure are applied to a battery management unit (hereinafter also referred to as BMU) of a vehicle equipped with a battery pack 1 which is a high-voltage battery will be described with reference to FIGS. 1 to 13. Thereafter, in this embodiment, a charging system BCS and a battery evaluation system BRS including the battery monitoring device 20 will be described.

[0014] [BMU] The BMU includes the battery pack 1 shown in FIG. 1. The battery pack 1 includes a sealed container 11 that constitutes an outer shell, and a plurality of battery modules BM, a battery monitoring device 20, and a battery ECU 100 are housed inside the sealed container 11. The sealed container 11 is provided with a high-pressure protection valve HPV for exhausting the gas inside to the outside when the internal pressure increases. The battery pack 1 has each battery module BM adjusted to an appropriate temperature by a temperature control device (not shown).

[0015] A plurality of battery modules BM are power sources that are connected to electrical devices such as an electric motor for vehicle travel (not shown) and supply power to the electrical devices. The plurality of battery modules BM are electrically connected in series. Also, the plurality of battery modules BM are assembled batteries in which a plurality of battery cells C are electrically connected in series. In this embodiment, a battery pack 1 including three battery modules BM is illustrated, but the number of battery modules BM is not limited to this and can be any number. The number of battery cells C constituting the battery module BM can also be any number. Note that some of the battery modules BM may be electrically connected in parallel. Hereinafter, the battery cells C and the battery modules BM may be simply referred to as batteries. The battery module BM of this embodiment is a storage battery including a lithium-ion battery.

[0016] The battery cell C is a rechargeable secondary battery. The battery cell C is composed of a lithium-ion battery. The lithium-ion battery is configured, for example, as shown in FIG. 2, to employ lithium iron phosphate LFP or nickel manganese cobalt NMC as a positive electrode agent and graphite as a negative electrode agent. Also, the lithium-ion battery is configured, for example, such that the positive electrode current collector is made of aluminum and the negative electrode current collector is made of copper. The lithium-ion battery configured in this way has excellent charge and discharge cycle characteristics, while having a feature that the electrode potential is very close to the lithium precipitation potential and lithium is likely to precipitate in the charged state.

[0017] As shown in FIG. 3, the battery monitoring device 20 is electrically connected to each battery module BM via a connection member 21. The connection member 21 includes a flexible printed circuit board (FPC) on which a wiring pattern is printed. The battery monitoring device 20 includes sensor units 30A, 30B, 30C having the same number as the respective battery modules BM and monitoring modules 50A, 50B, 50C having the same number as the respective battery modules BM. Since the basic configurations of the sensor units 30A, 30B, 30C are the same, they will not be described individually but will be collectively described as the sensor unit 30. Also, since the basic configurations of the monitoring modules 50A, 50B, 50C are the same, they will not be described individually but will be collectively described as the monitoring module 50.

[0018] The sensor unit 30 detects the state of each battery module BM. As shown in FIG. 4, the sensor unit 30 includes a temperature sensor 31, a current sensor 32, a voltage sensor 33, a strain sensor 34, a gas sensor 35, an internal pressure sensor 36 of the battery pack, a deposition amount detection unit 37, and a film detection unit 38. At least some of the various sensors constituting the sensor unit 30 are mounted on the flexible printed circuit board FPC. Note that it is not necessary for all of the various sensors constituting the sensor unit 30 to be mounted on the flexible printed circuit board FPC. However, since it is preferable for the temperature sensor 31, the strain sensor 34, and the gas sensor 35 to be close to the battery cell C, it is desirable to mount them on the flexible printed circuit board FPC.

[0019] The temperature sensor 31 is a sensor that detects the battery temperature of a lithium-ion battery. As shown in FIG. 1, a plurality of temperature sensors 31 are mounted on the flexible printed circuit board FPC. The flexible printed circuit board FPC is mounted with the same number of temperature sensors 31 as the battery cells C or slightly fewer than the battery cells C so that the battery temperatures of all the lithium-ion batteries constituting the battery module BM can be grasped. Note that the battery temperature may be estimated from the measurement result of the internal impedance of the battery cell C. In this case, the means for estimating the battery temperature functions as the temperature sensor 31.

[0020] The current sensor 32 is a sensor that detects the current flowing through the battery module BM. When each battery module BM is electrically connected in series, one current sensor 32 is sufficient for the battery pack 1.

[0021] In addition to the function of detecting the cell voltage of each battery cell C, the voltage sensor 33 can detect the voltage of the battery module BM as a block voltage. The voltage sensor 33 can be configured, for example, as a flying capacitor type circuit that sequentially charges the cell voltage of each battery cell C to a capacitor and detects the voltage between the terminals of the capacitor as the cell voltage.

[0022] The strain sensor 34 is a sensor that detects the strain of each battery cell C caused by gas generation or the like inside each battery cell C. Note that the strain of the battery cell C may be detected by another sensor such as an ultrasonic sensor instead of the strain sensor 34.

[0023] The gas sensor 35 is a sensor for detecting gas leakage from each battery cell C. The gas sensor 35 is configured to be able to detect at least one of hydrogen, carbon monoxide, carbon dioxide, and hydrogen fluoride that are generated when an abnormality occurs in a lithium ion battery, for example.

[0024] The in-pack pressure sensor 36 is a sensor that detects the pressure inside the sealed container 11 of the battery pack 1 as the in-pack pressure. The in-pack pressure sensor 36 is configured, for example, as an atmospheric pressure range type pressure sensor with the atmospheric pressure as a reference.

[0025] The deposition amount detection unit 37 is a device that detects lithium deposition in a lithium ion battery. The deposition amount detection unit 37 estimates the lithium deposition amount from the behavior by utilizing the correlation between the lithium deposition amount in the lithium ion battery and the behavior of the current and voltage when both ends of the lithium ion battery are short-circuited.

[0026] As shown in FIG. 5, the precipitation amount detection unit 37 includes a short-circuit circuit 371 that temporarily short-circuits both ends of the lithium-ion battery to discharge it, and an arithmetic unit 372 that estimates the lithium precipitation amount based on the behavior of the current and voltage when the lithium-ion battery is short-circuited by the short-circuit circuit 371. The short-circuit circuit 371 is mounted on the flexible printed circuit board FPC. Further, the arithmetic unit 372 is mounted on the monitoring module 50.

[0027] Although not shown, the short-circuit circuit 371 includes a short-circuit switch, a coil, and a capacitor for short-circuiting both ends of the lithium-ion battery. The internal resistance of the lithium-ion battery, the coil of the short-circuit circuit 371, and the capacitor constitute a self-resonant circuit.

[0028] When both ends of the lithium-ion battery are short-circuited, the arithmetic unit 372 extracts a resistance change component that is correlated with the lithium precipitation amount included in at least one of the signal waveforms of the current and voltage flowing through the short-circuit circuit 371, and calculates an estimated value of the lithium precipitation amount from the extracted component.

[0029] The above estimation method has a very simple configuration and is a very useful method in that it can detect a specific battery degradation mode by adjusting the discharge frequency from the lithium-ion battery.

[0030] On the other hand, the internal resistance of the lithium-ion battery is about several mΩ to several hundred mΩ and is also liable to be affected by disturbances such as temperature and parasitic impedance. It has been found that it is difficult to accurately obtain the lithium precipitation amount by the above estimation method. This was found as a result of the inventors' intensive studies.

[0031] Taking this into account, as shown in FIG. 6, the arithmetic unit 372 of the precipitation amount detection unit 37 calculates a corrected value obtained by correcting the above estimated value with both the battery temperature detected by the temperature sensor 31 and the parasitic resistance value stored in advance in the storage unit 51 of the monitoring module 50 as the lithium precipitation amount.

[0032] The parasitic resistance value is a part of the parasitic impedance that occurs between the lithium-ion battery and the short-circuit circuit 371. The parasitic resistance value changes according to the battery temperature. Therefore, the arithmetic unit 372 corrects the parasitic resistance value stored in the storage unit 51 according to the battery temperature, and calculates the lithium precipitation amount using the corrected parasitic resistance value. Note that the arithmetic unit 372 also functions as calibration means for correcting the estimated value of the lithium precipitation amount in addition to the function as means for estimating the lithium precipitation amount.

[0033] Here, as shown in FIG. 7, the parasitic resistance value is obtained by connecting the precipitation amount detection unit 37 to a calibration device CD having a known impedance Z before connecting it to the lithium-ion battery. Specifically, as shown in FIG. 8, the short-circuit circuit 371 is connected to the calibration device CD, and the parasitic resistance value is obtained in this state. Then, the parasitic resistance value is stored in the storage unit 51 of the monitoring module 50. Next, the short-circuit circuit 371 is connected to the battery module BM, and the lithium precipitation amount is calculated in this state.

[0034] The precipitation amount detection unit 37 configured in this way can ensure robustness against parasitic impedance and temperature changes. This is very effective in accurately detecting the lithium precipitation amount.

[0035] The short-circuit circuit 371 of the present embodiment includes a coil and has a large size, so it is necessary to appropriately reduce the size in consideration of mountability. The size reduction can be realized, for example, by improving the saturation magnetic flux density of the coil. Specific means for size reduction include, for example, using a coil made of a material with a high magnetic flux density, or providing a gap to improve the saturation magnetic flux density.

[0036] The film detection unit 38 detects the thickness of the film formed at the interface between the negative electrode and the electrolyte during charging of the lithium-ion battery. This film is also called the SEI layer. SEI is an abbreviation for Solid Electrolyte Interphase.

[0037] The thickness of the SEI layer has a correlation with the behavior of current and voltage when the two ends of the lithium-ion battery are short-circuited by the short-circuit circuit 371. The film detection unit 38 estimates the thickness of the SEI layer from the behavior of current and voltage when the two ends of the lithium-ion battery are short-circuited by the short-circuit circuit 371. Specifically, when the two ends of the battery are short-circuited by the short-circuit circuit 371, the film detection unit 38 extracts a component having a correlation with the thickness of the SEI layer included in at least one of the signal waveforms of the current and voltage flowing through the short-circuit circuit 371, and estimates the thickness of the SEI layer from the extracted component. When detecting the thickness of the SEI layer, it is desirable to correct it with the battery temperature, similar to the detection of the lithium precipitation amount.

[0038] Here, the lithium precipitation amount and the thickness of the SEI layer are physical quantities that have a higher correlation with the capacity degradation of the battery than the voltage and current of the battery. In the present embodiment, the precipitation amount detection unit 37 and the film detection unit 38 constitute a "degradation detection unit" that detects a physical quantity having a higher correlation with the capacity degradation of the battery than the voltage and current of the battery. Further, the lithium precipitation amount is one of the factors leading to an abnormal heat generation phenomenon in which the temperature of the battery continues to rise unintentionally. Therefore, the precipitation amount detection unit 37 constitutes a "factor monitoring unit" that monitors the factors leading to the abnormal heat generation phenomenon.

[0039] As shown in FIG. 4, a battery state detection unit 39 for detecting the battery state is mounted on the flexible printed circuit board FPC. The battery state detection unit 39 detects, for example, a battery state in which the battery temperature rises excessively, a battery state of overcharge, a battery state in which the internal resistance changes greatly, etc., based on the sensor outputs of the temperature sensor 31, the current sensor 32, and the voltage sensor 33, respectively.

[0040] Subsequently, the monitoring module 50 will be described. The monitoring module 50 is a satellite module directly attached to the battery module BM. The monitoring module 50 is a device on the high-voltage side in the BMU. The monitoring module 50 constitutes an "abnormality detection unit" that is electrically connected to the battery and detects abnormalities in the battery.

[0041] The monitoring module 50 includes a memory unit 51, a wireless communication unit 52, an internal resistance detection unit 53, a monitoring IC 54, etc. The memory unit 51 stores various information such as a unique ID set for each monitoring module 50, the monitoring results of the battery module BM, and the aforementioned parasitic resistance value. The memory unit 51 is composed of a non-transitory physical storage medium.

[0042] The wireless communication unit 52 is a communication device that enables two-way communication with the battery ECU 100. The monitoring module 50 receives various signals from the battery ECU 100 and transmits the monitoring results of the monitoring module 50, etc., to the battery ECU 100.

[0043] The internal resistance detection unit 53 is a device that detects the internal resistance of the battery based on various information output from the sensor unit 30. Also, the change in the internal resistance of the battery is one of the factors leading to the abnormal heat generation phenomenon. For this reason, the internal resistance detection unit 53 constitutes a "factor monitoring unit" that monitors the factors leading to the abnormal heat generation phenomenon.

[0044] The monitoring IC 54 is electrically connected to the battery to detect abnormalities in the battery. The monitoring IC 54 suppresses the occurrence of the abnormal heat generation phenomenon based on the monitoring results of the factors leading to the abnormal heat generation phenomenon, detects the abnormal state occurring in the battery at the initial stage of the occurrence of the abnormal heat generation phenomenon, and implements countermeasures against the abnormal heat generation phenomenon based on the detection results of the abnormal state.

[0045] The monitoring IC 54 includes an ASIC circuit having an algorithm that performs at least a part of the monitoring of the factors leading to the abnormal heat generation phenomenon and the detection of the abnormal state occurring in the battery at the initial stage of the occurrence of the abnormal heat generation phenomenon. Specifically, the monitoring IC 54 is configured to have a diagnosis unit 541, an SOH estimation unit 542, and a monitoring control unit 543 as functional units that execute various controls.

[0046] Since the amount of lithium precipitation is a parameter that greatly affects the residual value of the battery, it is also important to verify the reliability of this parameter. The diagnosis unit 541 diagnoses the appropriateness of the precipitation amount detection unit 37 by comparing a predetermined battery state estimated from the amount of lithium precipitation with a battery state estimated from other elements other than the amount of lithium precipitation.

[0047] For example, as shown in FIG. 9, the diagnosis unit 541 estimates the volume ratio SOH of the battery from the amount of lithium precipitation detected by the precipitation amount detection unit 37. Further, the diagnosis unit 541 estimates the volume ratio SOH of the battery based on the sensor outputs of the temperature sensor 31, the current sensor 32, and the voltage sensor 33 respectively. Note that SOH is an abbreviation for State of Health.

[0048] Subsequently, the diagnosis unit 541 compares the volume ratio SOH estimated from the amount of lithium precipitation with the volume ratio SOH estimated from the temperature, current, and voltage of the battery using a state comparator, and diagnoses the appropriateness of the precipitation amount detection unit 37. For example, if the deviation between the volume ratio SOH estimated from the amount of lithium precipitation and the volume ratio SOH estimated from the temperature, current, and voltage of the battery is within a predetermined range, the diagnosis unit 541 diagnoses that the precipitation amount detection unit 37 is appropriate. On the other hand, if the deviation between the volume ratio SOH estimated from the amount of lithium precipitation and the volume ratio SOH estimated from the temperature, current, and voltage of the battery exceeds the predetermined range, the diagnosis unit 541 diagnoses that the precipitation amount detection unit 37 is inappropriate. When the precipitation amount detection unit 37 is diagnosed as inappropriate, the monitoring IC 54 prohibits the detection of the amount of lithium precipitation and the control process using the amount of lithium precipitation, or transmits a signal indicating the failure of the precipitation amount detection unit 37 to the battery ECU 100 via the wireless communication unit 52. In this embodiment, the volume ratio SOH of the battery is exemplified as the battery state estimated by the diagnosis unit 541, but the diagnosis unit 541 may be configured to estimate a battery state other than the volume ratio.

[0049] Here, Japanese Patent Application Laid-Open No. 2014-102076 discloses a method for calculating the full charge capacity of a battery. In this calculation method, first, the change amount of the charge and discharge amount between the first time point and the second time point is calculated by integrating the current value of the output current of the battery over time. Then, the OCVs at the first time point and the second time point are measured, and the remaining capacity SOCs at the first time point and the second time point are calculated using the SOC-OCV curve, and the change amount ΔSOC calculated as the deviation of the remaining capacity SOCs at each time point is calculated. Next, the full charge capacity of the battery is calculated by dividing the change amount of the charge and discharge amount by the change amount ΔSOC of the remaining capacity SOC. Further, the volume ratio SOH of the battery is obtained by dividing the above full charge capacity of the battery by the initial value of the full charge capacity.

[0050] However, the above methods for calculating the remaining capacity SOC and the volume ratio SOH cannot calculate the charge and discharge amount of the battery unless there is a certain amount of charge or discharge in order to avoid the influence of errors of the current sensor 32 and the voltage sensor 33. There is a lack of real-time performance and problems in practicality. Also, when calculating the charge and discharge amount, there is a problem that the calculation error of the volume ratio SOH expands with time due to the offset error of the current sensor 32.

[0051] In consideration of these, the SOH estimation unit 542 estimates the volume ratio SOH of the battery based on a physical quantity that has a higher correlation with the capacity degradation of the battery than the voltage and current of the battery. Note that the SOH estimation unit 542 constitutes a "volume ratio estimation unit".

[0052] One factor in the degradation of the battery is the increase in the internal resistance of the battery. The internal resistance of the battery has a strong correlation with physical quantities such as the lithium precipitation amount and the internal resistance of the battery. Also, the internal resistance of the battery has temperature dependence and affects the current and voltage of the battery.

[0053] Taking these factors into consideration, as shown in FIG. 10, the SOH estimation unit 542 of the present embodiment estimates the volumetric SOH using an estimation model of the volumetric SOH with respect to the lithium precipitation amount, the thickness of the SEI layer, the temperature of the battery, the current, and the voltage. The estimation model of the volumetric SOH is, for example, a control map or a function that defines the relationship between the volumetric SOH, the lithium precipitation amount, the thickness of the SEI layer, the temperature of the battery, the current, and the voltage. Note that the estimation model may be a model obtained by, for example, deep learning using a neural network, reinforcement learning, or deep reinforcement learning.

[0054] According to this, real-time battery state diagnosis, which was difficult in the estimation of the volumetric SOH based on the charge and discharge amount, becomes possible. In addition, by accurately measuring the temperature, the temperature influence on the internal resistance of the battery is excluded, and deterioration information can be appropriately extracted, so the accuracy is improved.

[0055] The monitoring control unit 543 suppresses the occurrence of the abnormal heat generation phenomenon based on the monitoring result of the factor leading to the abnormal heat generation phenomenon, detects the abnormal state occurring in the battery at the initial stage of the occurrence of the abnormal heat generation phenomenon, and implements a countermeasure against the abnormal heat generation phenomenon based on the detection result of the abnormal state. Although not shown, the monitoring IC 54 controls a circuit for equalizing the voltages of a plurality of battery cells C.

[0056] Next, the battery ECU 100 will be described. The battery ECU 100 is the main module in the BMU and controls the charge and discharge of each battery module BM. The battery ECU 100 is a device on the low voltage side in the BMU.

[0057] Specifically, the battery ECU 100 is composed of a microcomputer including a processor, a memory, an I / O, a wireless communication device 110, etc. The battery ECU 100 is configured to be able to communicate with each monitoring module 50A, 50B, 50C via the wireless communication device 110. Further, the battery ECU 100 is connected to various ECUs via a communication path such as CAN. Examples of the various ECUs include an ECU for thermal management that controls the temperature control device of the battery, an ECU of an HMI device mounted on the vehicle, etc. The battery ECU 100 can notify various battery states to the outside via an HMI device or the like.

[0058] The battery pack 1 configured as described above includes a rechargeable battery such as a lithium-ion battery. This type of battery may cause an abnormal heat generation phenomenon in which a specific member inside the battery generates heat due to some trigger, and the generated heat further causes other members to generate heat, and the temperature of the battery continues to rise unintentionally. When such an abnormal heat generation phenomenon occurs, the thermal reliability of the battery is significantly reduced, which is not preferable. Therefore, in a lithium-ion battery or the like, it is important to detect the presence or absence of an abnormal heat generation phenomenon of the battery to ensure thermal reliability.

[0059] Here, the output changes of various sensors before and after the abnormal heat generation phenomenon will be described with reference to FIG. 11. FIG. 11 shows an example of the verification results of the output changes of various sensors before and after the abnormal heat generation phenomenon by the present inventors.

[0060] As shown in FIG. 11, at the stage before the occurrence of the abnormal heat generation phenomenon, first, as a sign of battery abnormality, the volume change of the battery starts due to an increase in the gas pressure inside the battery cell. As a result, the output of the strain sensor 34 shows an increasing trend.

[0061] After that, when the volume change of the battery becomes large, the battery is damaged and gas leakage inside the battery cell starts. As a result, the output of the gas sensor 35 shows an increasing trend. When the battery is damaged, the gas pressure inside the battery decreases, and the output of the strain sensor 34 shows a decreasing trend.

[0062] Although not shown in FIG. 11, as the battery degradation progresses, lithium precipitation occurs inside the battery, or the thickness of the SEI layer increases, resulting in an increase in the internal resistance of the battery.

[0063] When the abnormal heat generation phenomenon occurs, the battery temperature and the pressure inside the battery pack 1 (i.e., the internal pressure of the pack) rise rapidly, and at the same time, the voltage of the battery drops rapidly. Furthermore, the output of the gas sensor 35 shows an increasing trend. These signs become prominent at the initial stage of the occurrence of the abnormal heat generation phenomenon.

[0064] Taking these into account, the battery monitoring device 20 executes control processing to prevent and detect the abnormal heat generation phenomenon at an early stage. Hereinafter, an example of the control processing executed by the battery monitoring device 20 will be described with reference to FIG. 12.

[0065] The control processing shown in FIG. 12 is executed by the battery monitoring device 20 periodically or irregularly, for example, during the period when the vehicle is started and until a predetermined time has elapsed after the vehicle stops. Each process shown in this flowchart is realized by each functional unit of the battery monitoring device 20. Also, each step for realizing this process is understood as each step for realizing the battery monitoring method.

[0066] As shown in FIG. 12, the battery monitoring device 20 reads various signals from the sensor unit 30 and the like at step S100. Then, at step S105, the battery monitoring device 20 determines whether or not the abnormal heat generation phenomenon has occurred. As described above, at the initial stage of the occurrence of the abnormal heat generation phenomenon, the battery temperature, the internal pressure of the pack, and the output of the gas sensor 35 rise rapidly, and at the same time, the voltage of the battery drops rapidly. Considering this, the battery monitoring device 20 determines whether or not the abnormal heat generation phenomenon has occurred based on the sensor outputs of at least some of the temperature sensor 31, the voltage sensor 33, the gas sensor 35, and the internal pressure sensor 36 of the pack.

[0067] When the occurrence of an abnormal heat generation phenomenon is detected, the battery monitoring device 20 shifts to step S110 and implements countermeasures against the abnormal heat generation phenomenon. This countermeasure includes at least one of external notification processing for notifying the outside of the occurrence of the abnormal heat generation phenomenon and battery protection processing by cooling and charge / discharge control of the battery.

[0068] In the external notification processing, for example, a signal indicating the occurrence of the abnormal heat generation phenomenon is output to the battery ECU 100, and a device having a notification function such as an HMI device is operated via the battery ECU 100 to notify the user and the battery administrator of the occurrence of the abnormal heat generation phenomenon.

[0069] In the battery protection processing, for example, a signal for instructing battery cooling is output to the battery ECU 100, and the temperature control device of the battery is operated via the battery ECU 100 to cool the battery. According to such battery cooling, it is possible to delay the progress of abnormal heat generation of the battery. Also, in the battery protection processing, for example, a signal for instructing the restriction of charge / discharge of the battery is output to the battery ECU 100, and the self-heating of the battery is suppressed by restricting the operation of the battery. Also by such charge / discharge control, it is possible to delay the progress of abnormal heat generation of the battery. The battery protection processing constitutes an extension process for extending the life of the battery.

[0070] Also, as one of the countermeasures against the abnormal heat generation phenomenon, the battery monitoring device 20 specifies abnormal ones among the plurality of battery cells C as abnormal cells based on at least one of the monitoring results of each of the plurality of battery cells C and the detection results of the abnormal state of the battery. According to this, it is possible to limit the use of the abnormal cells and delay the progress of the abnormal heat generation phenomenon.

[0071] Note that the countermeasures against the abnormal heat generation phenomenon are not limited to the above-described processing, and may be realized by processing other than those described above. The countermeasures against the abnormal heat generation phenomenon may be, for example, turning on a warning light or sounding an alarm sound.

[0072] On the other hand, when no abnormal heat generation phenomenon is detected, the battery monitoring device 20 proceeds to the processes after step S115. The processes after step S115 are processes for preventing the occurrence of an abnormal heat generation phenomenon.

[0073] At step S115, the battery monitoring device 20 determines whether overcharging of the battery is detected. Overcharging of the battery can be detected, for example, by monitoring the sensor output of the voltage sensor 33. When overcharging of the battery is detected, the battery monitoring device 20 executes a charge suppression process at step S120 and returns to step S115. In this charge suppression process, charging of the battery is suppressed or discharging of the battery is performed.

[0074] When overcharging of the battery is not detected, the battery monitoring device 20 determines at step S125 whether overheating of the battery is detected. Overheating of the battery can be detected, for example, by monitoring the sensor output of the temperature sensor 31. When overheating of the battery is detected, the battery monitoring device 20 performs output limitation and cooling control at step S130 and returns to step S115. In output limitation, for example, charging and discharging of the battery are suppressed. In cooling control, for example, the battery is cooled by a temperature control device of the battery.

[0075] When overheating of the battery is not detected, the battery monitoring device 20 determines at step S135 whether new lithium deposition is detected. Lithium deposition can be detected, for example, by monitoring an increase amount of the lithium deposition amount detected by the deposition amount detection unit 37.

[0076] When new lithium deposition is detected, the battery monitoring device 20 performs charging, regeneration control, and heating control at step S140 and returns to step S115. In charging and regeneration control, for example, charging of the battery is suppressed. In heating control, for example, the battery is heated by a temperature control device of the battery. Each process performed when lithium deposition is detected constitutes an extension process for extending the life of the battery.

[0077] If no new lithium precipitation is detected, the battery monitoring device 20 determines, at step S145, whether a change in the internal resistance of the battery has been detected. The internal resistance of the battery can be detected, for example, by monitoring an increase in the internal resistance detected by the internal resistance detection unit 53.

[0078] If a change in the internal resistance of the battery is detected, the battery monitoring device 20 performs, at step S150, output limitation of the battery, temperature control, and notification of the degree of deterioration, and returns to step S115. In the output control, for example, the discharge of the battery is suppressed. In the temperature control, for example, the battery temperature is adjusted so that the battery temperature is maintained within an appropriate range by the temperature control device. In the notification of the degree of deterioration, the degree of deterioration of the battery is determined from the internal resistance of the battery, and the determination result of the degree of deterioration or the replacement time of the battery estimated from the determination result is notified to the outside. Note that each process performed when a change in the internal resistance is detected constitutes an extension process for extending the life of the battery.

[0079] If no change in the internal resistance of the battery is detected, the battery monitoring device 20 determines, at step S155, whether the battery is deformed. The deformation of the battery can be detected by monitoring the sensor output amount of the strain sensor 34.

[0080] If the deformation of the battery is detected, the battery monitoring device 20 performs, at step S160, output limitation of the battery and returns to step S115. In the output control, for example, the charge and discharge of the battery are suppressed.

[0081] If the deformation of the battery is not detected, no sign of abnormal heat generation phenomenon is recognized, and it is considered to be in a normal state. Therefore, if the deformation of the battery is not detected, the battery monitoring device 20 ends the control process shown in FIG. 12.

[0082] By the way, the rapid electrification of vehicles is progressing, and a large number of used batteries are expected to be generated in the near future. Since manufacturing batteries involves a large amount of CO2 emissions and the use of rare metals, depending on the remaining capacity SOC and the state of health SOH of the used battery, reuse, rebuild, and recycling are selected, and the construction of a battery ecosystem adapted to a circular society is expected. To build such a battery ecosystem, it is important to accurately diagnose the value of the battery, such as the remaining capacity SOC and the state of health SOH. Also, after the in-vehicle use ends, a scenario is assumed where the battery is stored until the secondary use destination is determined. However, the battery continues to discharge even when not in use, and it is also assumed that deterioration may progress depending on the storage state. Therefore, as a secondary user, it is necessary to grasp the remaining capacity SOC and the state of health SOH of the battery at that moment, and the real-time nature of battery diagnosis becomes important.

[0083] As described above, the battery monitoring device 20 of the present embodiment can obtain the remaining capacity SOC and the state of health SOH in real time. Considering this, it is desirable to use the battery module BM and the battery monitoring device 20 as a battery unit UT and distribute them in the market in units of the battery unit UT. And it is desirable to manage the battery module BM by, for example, the battery management system BMS shown in FIG. 13.

[0084] The battery management system BMS includes a battery monitoring device 20 and a battery management device 60 attached to the battery module BM. The battery management device 60 includes a performance determination unit 61, a value setting unit 62, and a performance notification unit 63.

[0085] The performance determination unit 61 determines whether the battery can be reused based on the state of health SOH estimated by the SOH estimation unit 542 of the battery monitoring device 20. For example, if the state of health SOH estimated by the SOH estimation unit 542 is equal to or greater than a predetermined value, the performance determination unit 61 determines that reuse is possible, and if it is less than the predetermined value, it determines that reuse is not possible. Note that the performance determination unit 61 may be configured to determine whether the battery can be reused based on a battery state other than the state of health SOH.

[0086] The value setting unit 62 determines the presence or absence of battery abnormalities based on the volumetric ratio SOH estimated by the SOH estimation unit 542 of the battery monitoring device 20, and sets the residual value of the battery when there are battery abnormalities. For example, the value setting unit 62 estimates the residual value of the battery to be low as the volumetric ratio SOH decreases. Note that the value setting unit 62 may be configured to set the residual value of the battery based on battery states other than the volumetric ratio SOH.

[0087] The performance notification unit 63 determines whether the volumetric ratio SOH estimated by the SOH estimation unit 542 of the battery monitoring device 20 is within the allowable range of the volumetric ratio SOH shown in the battery specification data, and outputs the result of this determination externally.

[0088] The performance notification unit 63 acquires the battery specification data provided by the battery manufacturer or the like and stores it in the memory. Then, for example, when the volumetric ratio SOH estimated by the SOH estimation unit 542 is within the allowable range shown in the specification data, the performance notification unit 63 notifies the battery seller, secondary user, etc. to that effect. Also, for example, when the volumetric ratio SOH estimated by the SOH estimation unit 542 is outside the allowable range shown in the specification data, the performance notification unit 63 notifies the battery seller, secondary user, etc. that it is difficult to reuse the battery.

[0089] According to the battery monitoring device 20 and the battery monitoring method described above, effective countermeasures against abnormal heat generation, effective detection of the lithium precipitation amount, and effective estimation of the volumetric ratio SOH can be implemented. Specifically, it is as follows.

[0090] [Countermeasures against abnormal heat generation] The battery monitoring device 20 and the battery monitoring method monitor the factors leading to the abnormal heat generation phenomenon, and suppress the occurrence of the abnormal heat generation phenomenon based on the monitoring results of the factors. In addition, the battery monitoring device 20 and the battery monitoring method detect the abnormal state occurring in the battery at the initial stage of the occurrence of the abnormal heat generation phenomenon, and implement countermeasures against the abnormal heat generation phenomenon based on the detection results of the abnormal state. According to this, while preventing the occurrence of the abnormal heat generation phenomenon, even if the abnormal heat generation phenomenon occurs, it is possible to implement effective heat countermeasures such as implementing countermeasures from the initial stage of its occurrence.

[0091] In addition, the battery monitoring device 20 can achieve the following effects.

[0092] (1) The monitoring module 50 of the battery monitoring device 20 monitors factors leading to abnormal heat generation and detects the abnormal state of the battery in parallel. In other words, the monitoring module 50 performs detection of the abnormal state of the battery regardless of the monitoring result of factors leading to abnormal heat generation. According to this, for example, compared with the case where the abnormal state is detected after monitoring factors leading to abnormal heat generation, the abnormal state can be detected earlier, so that countermeasures against the abnormal heat generation phenomenon can be implemented earlier.

[0093] (2) Countermeasures when an abnormal heat generation phenomenon occurs include external notification processing for notifying the outside of the occurrence of the abnormal heat generation phenomenon, or battery protection processing by at least one of temperature adjustment control and charge / discharge control of the battery. When the countermeasures for the abnormal heat generation phenomenon include external notification processing, in addition to the countermeasures that the battery monitoring device 20 itself can take, it becomes easier to implement countermeasures by external devices of the battery monitoring device 20 or countermeasures in cooperation with external devices. Also, when the countermeasures for the abnormal heat generation phenomenon include battery protection processing, it becomes possible to appropriately protect the battery.

[0094] (3) The monitoring module 50 performs extension processing for extending the life of the battery according to the monitoring result of factors of the abnormal heat generation phenomenon. In this way, if configured to perform battery life extension processing according to the monitoring result of factors leading to abnormal heat generation, it becomes possible to appropriately extend the battery life.

[0095] (4) Factors leading to abnormal heat generation include at least one of lithium precipitation inside the battery and internal resistance of the battery. Lithium precipitation inside the lithium-ion battery and an increase in internal resistance are factors that cause abnormal heat generation of the battery. Therefore, by monitoring lithium precipitation and internal resistance, it becomes easier to prevent the occurrence of abnormal heat generation of the battery.

[0096] (5) The monitoring module 50 identifies abnormal ones among the plurality of battery cells C as abnormal cells based on at least one of the monitoring results of each of the plurality of battery cells C and the detection results of the abnormal states of the plurality of battery cells C. In this way, if it is configured to be able to identify abnormal cells from among the plurality of battery cells C, for example, it is possible to limit the use of abnormal cells to prevent the occurrence of abnormal heat generation phenomena or delay the progress of abnormal heat generation phenomena.

[0097] (6) The monitoring module 50 is configured to be able to detect at least one of abnormal internal pressure of the sealed container 11, abnormal battery temperature, abnormal battery voltage, and abnormal gas in the sealed container 11 as an abnormal state of the battery. In the initial stage of the occurrence of the abnormal heat generation phenomenon, the internal pressure of the sealed container 11 that houses the battery, the battery temperature, the battery voltage, and the gas state in the sealed container 11 become abnormal states. For this reason, if the monitoring module 50 is configured to be able to detect at least one of abnormal internal pressure of the sealed container 11, abnormal battery temperature, abnormal battery voltage, and abnormal gas in the sealed container 11, it becomes easier to detect the abnormal heat generation phenomenon at the initial stage of its occurrence.

[0098] (7) The battery monitoring device 20 includes an ASIC circuit having an algorithm that performs at least a part of monitoring factors leading to the abnormal heat generation phenomenon and detecting the abnormal state of the battery. According to this, it is possible to realize monitoring of factors leading to the abnormal heat generation phenomenon and detection of the abnormal state with a simple configuration.

[0099] (8) The monitoring module 50 is configured to be able to notify the outside of the degree of battery degradation based on the monitoring results of factors leading to the abnormal heat generation phenomenon, and the determination result of the degree of degradation or the battery replacement time estimated from the determination result. In this way, if it is configured to determine the degree of battery degradation from the monitoring results of factors leading to the abnormal heat generation phenomenon, a dedicated device for determining the degree of battery degradation becomes unnecessary. This contributes to the simplification of the battery monitoring device 20.

[0100] (9) The connecting member 21 that connects the battery and the monitoring module 50 includes a flexible printed circuit board FPC on which a part of the sensor unit 30 is mounted. In this way, by mounting a part of the sensor unit 30 on the flexible printed circuit board FPC that constitutes the connecting member 21, it is possible to monitor factors leading to abnormal heat generation of the battery at a position close to the battery.

[0101] [Detection of Lithium Deposition Amount] The deposition amount detection unit 37 of the battery monitoring device 20 calculates an estimated value of the lithium deposition amount based on at least one of the changes in current and voltage when both ends of the lithium-ion battery are short-circuited by the short-circuit circuit 371. Then, the deposition amount detection unit 37 corrects the estimated value of the lithium deposition amount with the battery temperature. According to this, the influence of the battery temperature included in the estimated value of the lithium deposition amount can be reduced, and the detection accuracy of the lithium deposition amount can be improved, so the reliability of the deposition amount detection unit 37 can be ensured.

[0102] Also, the deposition amount detection unit 37 corrects the estimated value of the lithium deposition amount with the parasitic resistance value stored in the storage unit 51. According to this, the influence of the parasitic impedance included in the estimated value of the lithium deposition amount can be reduced, and the detection accuracy of the lithium deposition amount can be improved, so the reliability of the deposition amount detection unit 37 can be ensured.

[0103] (1) Specifically, the deposition amount detection unit 37 corrects the parasitic resistance value stored in the storage unit 51 according to the battery temperature, and calculates the lithium deposition amount using the corrected parasitic resistance value. According to this, the influence of the battery temperature and the parasitic impedance included in the estimated value of the lithium deposition amount can be reduced, and the detection accuracy of the lithium deposition amount can be improved.

[0104] (2) The parasitic resistance value is obtained by connecting the short-circuit circuit 371 to a calibration device CD having a known impedance Z before connecting it to the lithium-ion battery. According to this, the parasitic resistance value of the deposition amount detection unit 37 can be accurately obtained. This greatly contributes to improving the detection accuracy of the lithium deposition amount.

[0105] (3) The battery monitoring device 20 includes a diagnosis unit 541 that diagnoses the suitability of the deposition amount detection unit 37 by comparing a predetermined battery state estimated from the lithium deposition amount with a predetermined battery state estimated from other elements other than the lithium deposition amount. According to this, since the diagnosis unit 541 can diagnose the reliability of the deposition amount detection unit 37, the reliability of the deposition amount detection unit 37 can be ensured.

[0106] [Modification Example of Battery Monitoring Device 20] The battery monitoring device 20 is not the same as the one described above and may be partially different from the one described above. In addition, the above technical matters can also be applied to devices and systems other than in-vehicle devices.

[0107] [Estimation of Volume Ratio SOH] The battery monitoring device 20 detects a physical quantity that has a higher correlation with the capacity degradation of the battery than the voltage and current of the battery, and estimates the volume ratio SOH of the battery based on the physical quantity. In this way, if the volume ratio SOH is estimated by a physical quantity that has a high correlation with the capacity degradation of the battery, the need to avoid the influence of errors is smaller than when obtaining the volume ratio SOH from the current and voltage of the battery, so the volume ratio SOH can be estimated in a short time. Therefore, according to the battery monitoring device 20 of the present invention, it is possible to grasp the battery state in a practical manner.

[0108] (1) Here, the lithium deposition amount and the thickness of the SEI layer are physical quantities that directly affect the capacity degradation of the battery. For this reason, by detecting the lithium deposition amount and the thickness of the SEI layer and obtaining the volume ratio SOH based on the lithium deposition amount and the thickness of the SEI layer, real-time performance can be ensured. In addition, the degree of cracking of the positive electrode active material agent inside the battery is a physical quantity that directly affects the capacity degradation of the battery. For this reason, not only the lithium deposition amount and the thickness of the SEI layer, but also a configuration in which the volume ratio SOH is obtained based on the degree of cracking of the positive electrode active material agent can improve the detection accuracy of the volume ratio SOH. The degree of cracking of the positive electrode active material agent can be estimated based on the behavior of the current and voltage when both ends of the lithium-ion battery are short-circuited, or based on the sensor output of the strain sensor 34 or the ultrasonic sensor.

[0109] (2) The amount of lithium precipitation and the thickness of the SEI layer in a lithium-ion battery are correlated with the behavior of the current and voltage when both ends of the lithium-ion battery are short-circuited. Taking this into account, the battery monitoring device 20 calculates at least one of the amount of lithium precipitation and the thickness of the SEI layer based on a change in at least one of the current and voltage when both ends of the lithium-ion battery are short-circuited by the short-circuit circuit 371.

[0110] (3) Specifically, the battery monitoring device 20 corrects at least one of the amount of lithium precipitation and the thickness of the SEI layer with the battery temperature. According to this, it is possible to reduce the influence of the battery temperature included in the estimated value of the amount of lithium precipitation and the thickness of the SEI layer, and improve the detection accuracy of the amount of lithium precipitation and the thickness of the SEI layer.

[0111] (4) The battery management system BMS determines the feasibility of secondary use of the battery based on the volumetric ratio SOH estimated by the SOH estimation unit 542 of the battery monitoring device 20. According to this, when the battery is to be used secondarily, it becomes easier to determine which of reuse, rebuild, and recycle should be selected. This greatly contributes to the construction of a battery ecosystem adapted to a recycling-oriented society.

[0112] (5) The battery management system BMS determines the presence or absence of an abnormality in the battery based on the volumetric ratio SOH estimated by the SOH estimation unit 542 of the battery monitoring device 20, and sets the residual value of the battery when there is an abnormality in the battery. Also by this, when the battery is to be used secondarily, it becomes easier to determine which of reuse, rebuild, and recycle should be selected, so it contributes to the construction of a battery ecosystem adapted to a recycling-oriented society.

[0113] (6) The battery management system BMS determines whether the volumetric efficiency SOH estimated by the SOH estimation unit 542 of the battery monitoring device 20 is within the allowable range of the volumetric efficiency SOH shown in the battery specification data, and outputs the result of this determination externally. Also by this, when reusing the battery, it becomes easier to determine which of reuse, rebuild, and recycle should be selected, thus greatly contributing to the construction of a battery ecosystem adapted to a recycling-based society.

[0114] [Modification Example of Battery Management System BMS] The battery management system BMS is not the same as the one described above and may be partially different from the one described above. Also, the above technical matters are applicable to devices and systems other than in-vehicle devices.

[0115] The above is the explanation regarding the BMU etc. Hereinafter, the charging system BCS and the battery evaluation system BRS will be described.

[0116] [Charging System BCS] Hereinafter, the charging system BCS will be described with reference to FIGS. 14 to 19. The charging system BCS is a system for charging the battery modules BM included in the battery pack 1. The charging system BCS is applied, for example, to a vehicle charging station.

[0117] As shown in FIG. 14, the charging system BCS includes a battery monitoring device 20, a battery ECU 100, a charger 120, and a charging cable CC. In this embodiment, the battery monitoring device 20 and the battery ECU 100 included in the battery pack 1 constitute battery-side devices that monitor the battery state including the lithium precipitation amount in the lithium-ion battery.

[0118] The battery module BM is connected to the vehicle's power control unit PCU and motor generator MG via a switch SW2 such as a system main relay. When, for example, the vehicle's start switch is turned on, the battery module BM turns on the switch SW2 and is electrically connected to the motor generator MG via the power control unit PCU, enabling charge and discharge.

[0119] The battery monitoring device 20 and the battery ECU 100 are basically configured in the same manner as described above. The battery ECU 100 can communicate with the charger 120 via the communication device CE. When the battery ECU 100 is in a state where it can communicate with the charger 120, it notifies the charger 120 of battery information including battery states such as the lithium precipitation amount and the remaining capacity SOC. In addition, the battery ECU 100 determines whether it is in a chargeable state and notifies the charger 120 of the determination result as one piece of battery information. Furthermore, the battery ECU 100 sets the CC charge current, which is the target current during constant current charging, and the CV charge voltage, which is the target voltage during constant voltage charging, and notifies these set values to the charger 120. Note that the communication between the communication device CE and the charger 120 is performed via the communication lines included in the CAN and the charging cable CC.

[0120] The charging cable CC electrically connects the battery module BM and the charger 120. The charging cable CC is composed of a cable, a charging connector (not shown), a control box (not shown), etc.

[0121] The charger 120 is a device that charges the battery module BM. The charger 120 is composed of devices compliant with charging standards such as CHAdeMO, CCS, and GB / T. A switch SW1 for turning on and off the electrical connection between the charger 120 and the battery module BM is provided between the charger 120 and the battery module BM. This switch SW1 may be provided on the charger 120 side or on the vehicle side.

[0122] The charger 120 includes an information acquisition unit 121, a charging determination unit 122, a charging control unit 123, and a charging time calculation unit 124. The information acquisition unit 121, the charging determination unit 122, the charging control unit 123, and the charging time calculation unit 124 are configured by, for example, a microcomputer including a processor, a memory, I / O, etc.

[0123] The information acquisition unit 121 acquires battery information including the state of the battery such as the lithium precipitation amount and the remaining capacity SOC from the battery monitoring device 20 and the battery ECU 100 during charging of the battery module BM, etc. Further, the information acquisition unit 121 acquires the CC charging current and the CV charging voltage from the battery ECU 100.

[0124] Here, the lithium precipitation amount is important information indicating the safety of the battery module BM. Therefore, the information acquisition unit 121 of the present embodiment is configured to notify the outside via the notification device ND of the battery information including the information indicating the lithium precipitation amount. Note that the notification device ND is composed of devices such as a display, a speaker, a lamp, etc.

[0125] The charging determination unit 122 determines whether or not the battery module BM can be charged based on the battery information acquired by the information acquisition unit 121. For example, the charging determination unit 122 determines whether or not the battery module BM can be charged based on the result of the determination by the battery ECU 100 as to whether or not it is in a chargeable state. Note that the charging determination unit 122 may be configured to determine whether or not charging is possible based on the lithium precipitation amount, etc. acquired by the information acquisition unit 121.

[0126] The charging control unit 123 charges the battery module BM based on the determination result of the charging determination unit 122. When the determination result of the charging determination unit 122 indicates that charging of the battery module BM is possible, the charging control unit 123 performs charging of the battery module BM, and when the determination result indicates that charging of the battery module BM is not possible, the charging control unit 123 does not perform charging of the battery module BM.

[0127] The charge control unit 123 of this embodiment is configured to charge the battery module BM by a CCCV charging method that performs charging at a constant voltage after charging at a constant current. Hereinafter, charging at a constant current may be referred to as CC charging, and charging at a constant voltage may be referred to as CV charging.

[0128] The charge time calculation unit 124 estimates the required charge time for charging based on the battery state acquired by the information acquisition unit 121, and notifies the outside of the information indicating the estimated required charge time by the notification device ND. The charge time calculation unit 124 can be configured to estimate the required charge time, for example, using a control map that defines the relationship between the remaining amount of the battery module BM and the required charge time. When the charger 120 notifies the required charge time to the outside by the notification device ND, it is desirable that the charger 120 be notified including how much the current rapid charging can be shortened compared to normal charging. Further, it is desirable that the charger 120 notify the remaining time until charging is completed to the information terminal owned by the user.

[0129] The charging system BCS configured as described above is required to be capable of higher energy density and faster charging. Recently, on the charger 120 side, attempts have been made to shorten the charging time of the battery module BM by supporting 50 kW in the CHAdeMO 1.0 specification, 400 kW in the CHAdeMO 2.0 specification, and 900 kW in the CHAdeMO 3.0 specification.

[0130] The shortening of the charging time is possible by increasing the charging output, but the charging current increased by the high-output charging accelerates the lithium precipitation on the negative electrode of the battery, which may significantly impair the battery life and safety.

[0131] To avoid this, as shown in FIG. 15, a charging profile that does not result in a deteriorated or unsafe state, such as detecting an abnormality such as deep discharge of the battery by performing preliminary charging at a small current before CC charging, can be considered.

[0132] However, when performing pre-charging in consideration of safety, the charging time will be lengthened accordingly, which may cause discomfort to the user. In addition, when the charging time becomes longer than expected by the user, the user may feel anxious or irritated.

[0133] Taking these into consideration, the charging system BCS of the present embodiment is configured such that the charger 120 determines whether the battery module BM can be charged based on the battery information acquired from the battery monitoring device 20 and the battery ECU 100.

[0134] Hereinafter, the control process on the battery ECU 100 side at the start of charging of the battery module BM will be described with reference to FIG. 16. This control process is periodically or irregularly performed by the battery ECU 100. Each control step of the control process shown in FIG. 16 constitutes a function realization unit that realizes various functions executed by the battery ECU 100.

[0135] As shown in FIG. 16, the battery ECU 100 determines in step S200 whether the charger 120 is connected. The battery ECU 100 waits until the charger 120 is connected, and when the charger 120 is connected, it proceeds to step S210.

[0136] The battery ECU 100 executes initial processing in step S210. In the initial processing, the battery ECU 100 initializes flags and the like, and acquires the monitoring results of the battery monitoring device 20.

[0137] Subsequently, the battery ECU 100 determines whether the battery module BM is in a chargeable state. For example, the battery ECU 100 determines that charging is possible if the lithium precipitation amount is within a predetermined value, and determines that charging is impossible if the lithium precipitation amount exceeds the predetermined value. Note that the battery ECU 100 may also be configured to determine that charging is impossible even in the case of an overcharged state or a deep discharged state.

[0138] When charging the battery module BM is possible, the battery ECU 100 sets the charging amount to the battery module BM in step S230. The battery ECU 100 obtains the charging amount to the battery module BM based on, for example, the remaining capacity SOC, volume ratio SOH, etc. of the battery module BM. Also, the battery ECU 100 sets the CV charging voltage in step S240. The battery ECU 100 sets, as the CV charging voltage, for example, the voltage value recommended as the charging voltage of the battery module BM. Further, the battery ECU 100 sets the CC charging current in step S250. The battery ECU 100 sets, as the CC charging current, for example, the current value recommended as the charging current of the battery module BM. Then, the battery ECU 100 notifies the charger 120 of the battery information indicating the battery state including the lithium precipitation amount, and various settings including the CV charging voltage and the CC charging current, and exits this control process.

[0139] On the other hand, when charging the battery module BM is not possible, the battery ECU 100 notifies the charger 120 in step S270 that charging the battery module BM is not possible, and exits this control process.

[0140] Next, the control process on the charger 120 side during charging of the battery module BM will be described with reference to FIG. 17. This control process is periodically or irregularly performed by the charger 120. Each control step of the control process shown in FIG. 17 constitutes a function realization unit that realizes various functions executed by the charger 120.

[0141] As shown in FIG. 17, the charger 120 determines in step S300 whether it has received a notification issued by the battery ECU 100. The charger 120 waits until it receives a notification from the battery ECU 100, and when it receives a notification from the battery ECU 100, it proceeds to step S310. The charger 120 determines the possibility of charging the battery module BM based on the notification from the battery ECU 100 in step S310. Note that the process of step S310 is performed by the charging determination unit 122 of the charger 120.

[0142] When the notification from the battery ECU 100 indicates that charging is impossible, the charger 120, at step S320, externally notifies the notification device ND of information indicating that charging the battery module BM is impossible and information indicating the lithium precipitation amount, and does not perform charging of the battery module BM.

[0143] On the other hand, when the notification from the battery ECU 100 indicates that charging is possible, the charger 120 starts CC charging at step S330. The charger 120 charges the battery module BM using the CC charging current set by the battery ECU 100 as the target current amount.

[0144] Subsequently, the charger 120 determines at step S340 whether the voltage of the battery module BM has reached a predetermined voltage. This determination process determines whether it is the switching timing from CC charging to CV charging. The predetermined voltage is set to, for example, the CV charging voltage.

[0145] When the voltage of the battery module BM has not reached the predetermined voltage, the charger 120 determines at step S350 whether it has received a notification of an update to the CC charging current setting from the battery ECU 100.

[0146] Here, during CC charging, the battery ECU 100 periodically or irregularly executes the setting update process shown in FIG. 18. Specifically, as shown in FIG. 18, the battery ECU 100 determines at step S500 whether the lithium precipitation amount is greater than a predetermined threshold value. This threshold value is set to a value assuming the lithium precipitation amount deposited during battery abnormality. If the lithium precipitation amount is less than or equal to the predetermined threshold value, the battery ECU 100 skips the subsequent steps and exits the setting update process. If the lithium precipitation amount is greater than the predetermined threshold value, it proceeds to step S510. The battery ECU 100 re - sets the CC charging current to be smaller than the current value at step S510. For example, the battery ECU 100 re - sets the current value before the lithium precipitation amount exceeds the predetermined threshold value as the CC charging current. Then, the battery ECU 100 notifies the charger 120 of the update to the CC charging current setting at step S520.

[0147] Returning to FIG. 17, when the charger 120 receives a notification of an update to the setting of the CC charging current from the battery ECU 100, at step S360, the charger 120 updates the CC charging current to the current amount notified from the battery ECU 100. That is, when the amount of lithium precipitation increases beyond a predetermined threshold during CC charging, the charger 120 decreases the current amount of the constant current. Note that the process of step S360 is performed by the charging control unit 123 of the charger 120.

[0148] Further, when the voltage of the battery module BM reaches a predetermined voltage, the charger 120 proceeds to step S370 and starts CV charging. The charger 120 charges the battery module BM using the CV charging voltage set by the battery ECU 100 as the target voltage.

[0149] Subsequently, at step S330, the charger 120 determines whether the current flowing through the battery module BM is equal to or less than a predetermined value, or whether the elapsed time since the start of charging of the battery module BM is equal to or more than a predetermined time.

[0150] When the current flowing through the battery module BM is greater than the predetermined value and the elapsed time since the start of charging is within the predetermined time, the charger 120 continues CV charging. Also, when the current flowing through the battery module BM is equal to or less than the predetermined value, or when the elapsed time since the start of charging exceeds the predetermined time, the charger 120 exits this control process after executing the charging end process at step S390. In the charging end process, for example, the charging completion, the charged amount, the battery state, etc. are notified to the user by the notification device ND.

[0151] The charging system BCS described above includes a charger 120 for a battery module BM including a lithium-ion battery. The charger 120 includes an information acquisition unit 121 that acquires battery information from a battery-side device, a charging determination unit 122 that determines whether charging of the battery module BM is possible based on the battery information, and a charging control unit 123 that charges the battery module BM based on the determination result of the charging determination unit 122. In this way, if the charger 120 is configured to determine whether charging of the battery module BM is possible based on the battery information acquired from the battery-side device, the charging time can be shortened compared to a configuration that determines whether charging of the battery module BM is possible by performing preliminary charging.

[0152] Further, the charging system BCS of the present embodiment has the following features. (1) The charging control unit 123 of the charger 120 is configured to charge the battery module BM by a CCCV charging method in which charging is performed at a constant voltage after charging at a constant current. Then, as shown in FIG. 19, for example, when the amount of lithium precipitation increases beyond a predetermined threshold during CC charging, the charging control unit 123 decreases the current amount of the constant current. According to this, since the amount of lithium precipitation during CC charging is suppressed, it is possible to suppress an increase in the charging time of the battery module BM while ensuring the safety of the battery module BM.

[0153] (2) When charging by the charger 120 is started, the battery-side device periodically determines whether the amount of lithium precipitation has increased beyond a threshold. Then, when the amount of lithium precipitation increases beyond the threshold, the battery-side device sets the target current amount during charging at a constant current to a value smaller than the current current amount and notifies the charger 120 of the target current amount. When the charging control unit 123 acquires the target current amount from the battery-side device during CC charging, it adjusts the current amount of the constant current based on the target current amount. In this way, if the battery-side device periodically monitors the amount of lithium precipitation and the charger 120 side adjusts the current amount suitable for charging at a constant current based on the monitoring result, it is possible to control to maximize the charging rate so that lithium precipitation does not occur. As a result, it is possible to appropriately shorten the waiting time depending on the charging time of the user.

[0154] (3) The charger 120 estimates the required charging time based on the battery state and notifies the outside through the notification device ND of the information indicating the estimated required charging time. According to this, since the user can grasp the general waiting time, it is possible to reduce the psychological burden on the user during the charging of the battery module BM.

[0155] (4) The charger 120 notifies the outside through the notification device ND of the information indicating the lithium precipitation amount. In this way, if it is possible to provide the user not only with the information indicating the required charging time but also with the information indicating the lithium precipitation amount, the user can also grasp the safety of the lithium-ion battery, and it is possible to reduce the user's anxiety about the lithium-ion battery.

[0156] [Modification Example of Charging System BCS] The charging system BCS is not the same as the one described above and may be partially different from the one described above. Also, the above technical matters are applicable to devices and systems other than in-vehicle devices.

[0157] [Battery Evaluation System BRS and Battery Evaluation Method] In a lithium-ion battery, lithium may precipitate due to charging at low temperatures or rapid charging. If the lithium precipitation progresses, an internal short circuit may occur, leading to the risk of ignition and smoke. Therefore, when reusing a storage battery including a lithium-ion battery, it is desirable to grasp the safety considering not only the degree of deterioration but also the lithium precipitation condition.

[0158] Taking this into account, the battery evaluation system BRS and the battery evaluation method of the present embodiment are configured to determine the safety of the storage battery based on the lithium precipitation amount. Also, the battery evaluation system BRS functions as a support system for supporting the reuse and rebuild of the battery module BM. Hereinafter, the battery evaluation system BRS and the battery evaluation method will be described with reference to FIGS. 20 to 22.

[0159] As shown in FIG. 20, the battery evaluation system BRS includes a battery monitoring device 20 as a battery monitoring unit that monitors the state of the battery module BM, and an evaluation device 130 that evaluates the battery module BM.

[0160] The battery monitoring device 20 is basically configured in the same manner as described above. The battery monitoring device 20 is configured to be able to calculate the lithium precipitation amount in the lithium-ion battery included in the battery module BM as one index indicating the battery state. The battery monitoring device 20 can output to the outside battery state information including the monitoring result of the battery state including the lithium precipitation amount by using the wireless communication unit 52 of the monitoring module 50. This battery state information includes, in addition to the lithium precipitation amount, battery form information indicating the use of the battery module BM, the usage history of the battery module BM, and the like. Note that the battery monitoring device 20 may be configured to be able to output battery state information and the like to the outside by a communication device other than the wireless communication unit 52 of the monitoring module 50.

[0161] The evaluation device 130 is configured to be able to communicate with the battery monitoring device 20, a data center where market trading information of reused batteries is stored, information terminals UA, UB, UC, etc. held by users, salespersons, secondary users, etc. via a wired or wireless communication network. The evaluation device 130 acquires battery state information from the battery monitoring device 20 and evaluates the battery module BM based on the battery state information. The evaluation device 130 of the present embodiment includes a safety determination unit 131, a value calculation unit 132, a usage proposal unit 133, a reuse determination unit 134, and an information output unit 135.

[0162] The safety determination unit 131 determines the safety of the battery module BM based on the amount of lithium precipitation in the lithium-ion batteries included in the battery module BM. The safety determination unit 131 determines that the higher the safety, the lower the amount of lithium precipitation, and the lower the safety, the higher the amount of lithium precipitation. If the battery module BM includes even one lithium battery lacking in safety, the safety of the battery module BM is impaired. For this reason, the safety determination unit 131 can rank the safety of each of the plurality of lithium-ion batteries included in the battery module BM based on the amount of lithium precipitation.

[0163] The value calculation unit 132 calculates the value of the battery module BM in consideration of the determination result of the safety of the battery module BM. In the value calculation unit 132, for example, it is calculated that the battery module BM with higher safety has a higher price than the battery module BM with lower safety.

[0164] The value calculation unit 132 acquires, for example, as shown in FIG. 21, the degradation state based on the volume ratio SOH, the safety based on the amount of lithium precipitation, the battery form information including the use, and the usage history from the battery monitoring device 20, and acquires the market trading information of the reuse battery from the data center. Then, the value calculation unit 132 calculates the purchase price of the battery module BM based on the degradation state, safety, battery form information, usage history, and market trading information. The value calculation unit 132 refers to, for example, a map associating the degradation state, safety, battery form information, usage history, market trading information, and the purchase price of the battery module BM, and calculates the purchase price of the battery module BM based on the information acquired from the battery monitoring device 20 and the data center. Note that the value calculation unit 132 may be configured to calculate the selling price of the battery module BM.

[0165] The Usage Proposal Unit 133 proposes the transitional usage of the battery module BM during reuse, taking into account the determination result of the safety of the battery module BM. For example, as shown in FIG. 21, the Usage Proposal Unit 133 proposes the recommended usage of the battery module BM during reuse based on the degradation state, safety, battery form information, and usage history. The Usage Proposal Unit 133, for example, refers to a map associating the degradation state, safety, battery form information, usage history, and usage during reuse, and obtains the recommended usage of the battery module BM during reuse based on the information acquired from the battery monitoring device 20.

[0166] The Reuse Determination Unit 134 determines the feasibility of reusing the lithium-ion batteries, taking into account the safety of each of the plurality of lithium-ion batteries constituting the battery module BM. For example, the Reuse Determination Unit 134 determines that reuse is possible if the lithium precipitation amount is equal to or less than a predetermined value, and determines that reuse is not possible if the lithium precipitation amount exceeds the predetermined value.

[0167] When rebuilding different batteries by reorganizing reusable lithium-ion batteries, the Information Output Unit 135 outputs, as rebuild information, a combination of lithium-ion batteries suitable for the usage of different batteries, taking into account the safety of the lithium-ion batteries, as shown in FIG. 22.

[0168] Here, the optimal combination of lithium-ion batteries may vary depending on the usage mode of the battery after rebuilding. Therefore, it is desirable that the Information Output Unit 135 outputs a combination corresponding to the usage mode of the battery after rebuilding to the rebuild system RS that manufactures the rebuilt battery. For example, when the usage mode of the battery after rebuilding is for long-term use such as a stationary type, the Information Output Unit 135 outputs, as rebuild information, a combination that has a long life and high safety. Also, for example, when the battery after rebuilding is to be used for a short period, the Information Output Unit 135 outputs, as rebuild information, a combination that emphasizes matters other than the life.

[0169] The battery evaluation system BRS and the battery evaluation method described above monitor the battery state of the battery module BM, and evaluate the battery module BM based on the battery state information including the monitoring result of the battery state. The battery monitoring device 20 calculates the amount of lithium precipitation in the lithium-ion battery as one index indicating the battery state. The evaluation device 130 determines the safety of the battery module BM based on the amount of lithium precipitation. According to this, since an index related to the safety of the battery module BM such as the lithium precipitation state is determined, it is possible to appropriately perform an evaluation including whether or not the safety requirement is satisfied.

[0170] Further, the battery evaluation system BRS and the battery evaluation method of the present embodiment have the following features. (1) The evaluation device 130 includes a value calculation unit 132 that calculates the value of the battery module BM in consideration of the determination result of the safety of the battery module BM. According to this, it is possible to provide the user with appropriate value of the battery module BM as information.

[0171] (2) The evaluation device 130 includes an application proposal unit 133 that proposes the application of the battery module BM at the time of reuse in consideration of the determination result of the safety of the battery module BM. According to this, it is possible to provide the user with appropriate application of the battery module BM as information.

[0172] (3) The evaluation device 130 ranks the safety of each of the plurality of lithium-ion batteries included in the battery module BM based on the amount of lithium precipitation. According to this, it is possible to provide the user with appropriate states of the plurality of lithium-ion batteries constituting the battery module BM as information.

[0173] (4) The evaluation device 130 includes a reuse determination unit 134 that determines the possibility of reusing the lithium-ion battery in consideration of the safety of each of the plurality of lithium-ion batteries. According to this, even when the entire battery module BM cannot be reused, it becomes easier to reuse the lithium-ion battery with high safety in the battery module BM.

[0174] (5) When rebuilding a battery different from the battery module BM by reorganizing a reusable lithium-ion battery, the evaluation device 130 outputs, as rebuild information, a combination of lithium-ion batteries suitable for the use of the other battery, taking into account the safety of the lithium-ion battery. According to this, even when the entire battery module BM cannot be reused, it becomes easier to reuse by constructing another storage battery using a highly safe lithium-ion battery in the battery module BM.

[0175] (6) In addition to the lithium precipitation amount, the battery state information includes at least one of the use, usage history, and deterioration state of the lithium-ion battery. In this way, if the configuration is such that the battery module BM is evaluated using various pieces of information, a multifaceted evaluation of the battery module BM becomes possible.

[0176] [Modification Examples of Battery Evaluation System BRS and Battery Evaluation Method] The battery evaluation system BRS and the battery evaluation method are not the same as those described above, and may be partially different from those described above. Also, the above-described technical matters can be applied to devices and systems other than in-vehicle devices.

[0177] (Second Embodiment) Next, the second embodiment will be described with reference to FIGS. 23 to 25. In this embodiment, an example of identifying the cause of an abnormality in the battery module BM based on the usage history and manufacturing history of the battery module BM will be described.

[0178] First, the manufacturing process until the battery pack 1 is mounted on the vehicle will be described with reference to FIG. 23. As shown in FIG. 23, the battery pack 1 is mounted on the vehicle through the manufacturing process of the battery cell C → the manufacturing process of the battery module BM → the manufacturing process of the battery pack 1 → the assembly process to the vehicle.

[0179] The manufacturing process for the battery cell C involves the formation of the electrode body, cell assembly, electrolyte injection, initial charge / discharge, and performance testing in this order. In the performance testing, for example, inspection equipment is used to perform an appearance inspection of the battery cell C alone, a foreign object inspection, and a battery characteristic inspection.

[0180] Here, in lithium ion batteries, lithium ions may be reduced and precipitated at the negative electrode. In particular, when charging with a large current or at a low temperature, or when metal foreign matter is mixed into the battery and the current density is concentrated, the lithium ions released from the positive electrode active material do not enter the negative electrode active material and tend to precipitate on the negative electrode surface. When lithium precipitates on the negative electrode, the amount of lithium ions contributing to the battery reaction decreases, which may lead to a decrease in capacity or an internal short circuit.

[0181] For this reason, in the manufacturing process of battery cell C, the current and temperature conditions under which lithium precipitation does not occur are calculated and mapped, and manufacturing measures and inspections are implemented to prevent metallic foreign matter from being mixed into battery cell C. In the manufacturing process of battery cell C, for example, whether or not lithium has precipitated is inspected by shining light on the electrode surface of battery cell C, and the ease of lithium precipitation is inspected by measuring the resistance distribution on the surface of the negative electrode active material.

[0182] In the subsequent manufacturing process of the battery module BM, module assembly is performed in which the battery cells C are assembled together, and sensor assembly is performed in which the sensor unit 30 and the like are assembled to the assembly of the battery cells C. In this manufacturing process of the battery module BM, the battery monitoring device 20 is attached to the battery module BM. As a result, at the manufacturing stage of the battery module BM, the amount of lithium deposition and the like can be monitored by the battery monitoring device 20.

[0183] In the next manufacturing process of the battery pack 1, pack assembly is performed in which the assembled battery modules BM are housed in a sealed container 11. In this process, inspections such as checking electrical continuity are appropriately performed.

[0184] In the subsequent vehicle assembly process, the battery pack 1 is assembled to the vehicle and vehicle inspections are carried out. In the vehicle inspections, continuity checks with in-vehicle devices and the like are carried out. Thereafter, the vehicle equipped with the battery pack 1 is shipped from the factory to the user.

[0185] Incidentally, although it is conceivable to disassemble the battery cell C and inspect the lithium precipitation amount, it is difficult to carry out this inspection method for the actually used battery cells C or the battery cells C within the manufacturing process, not to mention the development stage.

[0186] On the other hand, as shown in FIG. 24, the battery monitoring device 20 includes a precipitation amount detection unit 37 that calculates the lithium precipitation amount using the output of a sensor installed in the battery module BM, and a storage unit 51 that stores the temporal change in the lithium precipitation amount as one of the usage histories of the battery.

[0187] The battery monitoring device 20 stores, for example, the lithium precipitation amount and the like as one of the usage histories in the storage unit 51, which is a storage medium, when the vehicle is running by the user. Further, the battery monitoring device 20 stores the lithium precipitation amount and the like in the manufacturing process of the battery module BM, the manufacturing process of the battery pack 1, and the vehicle assembly process in the storage unit 51 or an external storage device as one of the manufacturing histories.

[0188] Further, when an abnormality occurs in the lithium ion battery, the battery monitoring device 20 includes an abnormality specifying unit 544 that specifies the cause of the abnormality of the lithium ion battery based on the usage history stored in the storage unit 51 and the manufacturing history stored in the storage unit 51 or an external storage device. The abnormality specifying unit 544 uses the manufacturing history as reference data, compares the manufacturing history and the usage history, specifies the occurrence time of the abnormality of the lithium ion battery, and verifies the battery state before and after the occurrence time to specify the cause of the abnormality of the lithium ion battery. The abnormality specifying unit 544 specifies, for example, as shown in FIG. 25, the timing when the lithium precipitation amount increases as the occurrence time of the abnormality of the lithium ion battery.

[0189] For the rest, it is the same as the first embodiment. The battery monitoring device 20 of this embodiment can obtain the same effects as those achieved by the common configuration or equivalent configuration as the first embodiment in the same manner as the first embodiment.

[0190] Moreover, the battery monitoring device 20 of this embodiment has the following features. (1) The battery monitoring device 20 includes a storage unit 51 that stores the time change of the lithium precipitation amount as one of the usage history or manufacturing history of the lithium-ion battery. If it is configured in this way, the lithium precipitation amount can be appropriately detected non-destructively and in a short time, and the inspection of the lithium precipitation state can be carried out. In particular, since a sensor for detecting lithium precipitation is installed for the battery module BM, it is possible to detect the lithium precipitation state regardless of time and location. Furthermore, by storing the time change of the lithium precipitation amount in the storage unit 51 as one of the usage history or manufacturing history of the lithium-ion battery, it is possible to clearly grasp when lithium precipitated. This has the advantage of clarifying the responsibility for lithium precipitation.

[0191] (2) Also, when an abnormality occurs in the lithium-ion battery, the battery monitoring device 20 includes an abnormality specifying unit 544 that specifies the cause of the abnormality of the lithium-ion battery based on the usage history and the manufacturing history of the lithium-ion battery. In this way, if the cause of the abnormality of the lithium-ion battery is specified based on the history information including not only the usage history but also the manufacturing history, the search for the cause of the abnormality can be traced back not only to the usage stage but also to the manufacturing stage. This greatly contributes to clarifying the responsibility.

[0192] (Modification of the Second Embodiment) The battery monitoring device 20 of the second embodiment is not the same as the above-described one, and may be partially different from the above-described one. Also, the technical matters described in the second embodiment can be applied to devices and systems other than in-vehicle devices.

[0193] (Third Embodiment) Next, the third embodiment will be described with reference to FIGS. 26 to 33. In this embodiment, an example in which the battery management unit BMU of the present disclosure is applied to a stationary large-capacity power storage system BSS will be described.

[0194] As shown in FIGS. 26, 27, and 28, the large-capacity power storage system BSS includes a storage container SC, a plurality of battery modules BM, a blower device CM, a heater device HM, a battery management unit BMU, and the like.

[0195] The plurality of battery modules BM are each a storage battery including a lithium-ion battery. A sensor unit 30 is installed in each of the plurality of battery modules BM. This sensor unit 30 is configured in the same manner as that described in the first embodiment.

[0196] The storage container SC is a container that houses the plurality of battery modules BM. The storage container SC is appropriately provided with an opening for ensuring air permeability. The storage container SC is provided with a blower device CM and a heater device HM.

[0197] The blower device CM is a cooling element of the battery module BM and generates an air flow inside the storage container SC. The blower device CM may be configured as a device that sucks air inside the storage container SC, or may be configured as a device that pushes air inside the storage container SC. The operation of the blower device CM is controlled according to a control signal from a battery control device 140 described later.

[0198] The heater device HM is a heating element of the battery module BM and includes a heating element that generates heat when energized. The heater device HM may be configured to directly heat the battery module BM, or may be configured to indirectly heat the battery module BM. The operation of the blower device CM is controlled according to a control signal from a battery control device 140 described later.

[0199] The battery management unit BMU manages a plurality of battery modules BM. The battery management unit BMU includes a sensor unit 30 that monitors the battery state including the amount of lithium precipitation in a lithium-ion battery, and a battery control device 140 that performs charge control of the plurality of battery modules BM.

[0200] The battery control device 140 performs charge control of the plurality of battery modules BM based on the battery state monitored by the sensor unit 30. For example, the battery control device 140 charges the plurality of battery modules BM using electric power obtained from solar power generation or the like or electric power during a time band when the electricity bill is low.

[0201] Also, a notification device ND is connected to the battery control device 140. The battery control device 140 is configured to notify the outside via the notification device ND of the battery state and the like monitored by the sensor unit 30.

[0202] Here, in a lithium-ion battery, since the electrode potential during charging drops to near the oxidation-reduction potential of lithium, lithium is likely to precipitate in situations such as low-temperature charging, large-capacity charging, and overcharging. Lithium precipitation reduces the available lithium ions inside the battery and causes a rapid decrease in battery capacity. Also, if lithium precipitation continues, it may cause an internal short circuit and, in the worst case, may lead to thermal runaway of the battery.

[0203] Also, once the battery fails, it may become impossible to store the generated energy until it becomes widespread, and users and operators may suffer significant damage. Therefore, in order to continue using the battery safely and securely, in addition to performing charge and discharge while appropriately managing the temperature of the lithium-ion battery, it is required to detect early signs of battery failure such as an internal short circuit and minimize downtime.

[0204] On the other hand, for example, as shown in FIG. 29, when the temperature of the lithium-ion battery drops below a predetermined low-temperature threshold value, it is conceivable to use the electric power stored in the battery as a power source and raise the temperature of the battery by a heating element such as a heater device HM.

[0205] However, the above method is a control method that focuses only on the battery temperature. Depending on the charge and discharge rate of the battery, there may be cases where it is not necessarily necessary to raise the temperature of the battery. Also, if only the temperature of the battery is focused on, the temperature of the battery may be excessively controlled, and as a result, there is a possibility that the power stored in the battery may be excessively used. In addition, in the case of a large-scale power storage facility such as the large-capacity power storage system BSS, the temperature distribution of the battery becomes complicated, and it becomes difficult to appropriately grasp the temperature of the battery. Also, it is difficult to detect a battery failure such as an internal short circuit at an early stage only from the temperature information of the lithium-ion battery, and the system may fail before the operator can secure an appropriate amount of maintenance man-hours, resulting in a significant amount of downtime. Note that the charge and discharge rate is the speed of charging and discharging.

[0206] Taking these into consideration, the battery control device 140 is configured to heat the lithium-ion battery according to the lithium precipitation amount during charge control. Note that lithium precipitation can also occur other than during charge control. For this reason, it is desirable that the battery control device 140 heats the lithium-ion battery according to the lithium precipitation amount not only during charge control.

[0207] For example, as shown in FIG. 30, when the lithium precipitation amount increases beyond the first precipitation threshold Hi, the battery control device 140 starts energizing the heater device HM to heat the battery module BM. The heating of the battery module BM reduces the lithium precipitation amount. Then, when the lithium precipitation amount falls below the second precipitation threshold Lo which is smaller than the first precipitation threshold Hi, the battery control device 140 stops energizing the heater device HM to stop heating the battery module BM.

[0208] Here, as described above, lithium precipitation occurs not only during low-temperature charging but also in situations such as large-capacity charging and overcharging. In situations such as large-capacity charging and overcharging, the battery temperature of the battery module BM may be somewhat high.

[0209] Therefore, the battery control device 140 may be configured to heat the lithium-ion battery according to the lithium precipitation amount and the temperature of the battery module BM. For example, as shown in FIG. 31, when the lithium precipitation amount increases beyond the first precipitation threshold Hi and the battery temperature of the battery module BM falls below a predetermined low temperature threshold, the battery control device 140 may energize the heater device HM to heat the battery module BM.

[0210] In addition, when the lithium precipitation amount exceeds the first precipitation threshold Hi while the battery temperature of the battery module BM exceeds the low temperature threshold, the battery control device 140 may limit the charge and discharge of the battery module BM or notify the outside of the battery abnormality using the notification device ND.

[0211] Here, in order to suppress the downtime, for example, as shown in FIG. 32, it is desirable to perform battery replacement during the period from when the volume ratio SOH of the battery becomes somewhat small due to deterioration until the lithium precipitation amount reaches the amount that causes an internal short circuit of the battery.

[0212] Taking this into account, the battery control device 140 of the present embodiment estimates a desirable battery replacement period from the change in the volume ratio SOH and the change in the lithium precipitation amount output by the sensor unit 30, and notifies the outside by the notification device ND using the battery replacement period as a recommended period. According to this, since operators and the like can know the recommended period for battery replacement, it is possible to suppress the downtime due to maintenance and system failures including battery failures.

[0213] For the rest, it is the same as the first embodiment. The battery management unit BMU of the present embodiment can obtain the same effects as those of the first embodiment from the same configuration or equivalent configuration as that of the first embodiment.

[0214] In addition, the battery management unit BMU of the present embodiment has the following features. (1) When the lithium precipitation amount increases beyond a predetermined threshold value, the battery management unit BMU heats the battery module BM by a heater device HM that raises the temperature of the battery module BM. According to this, the lithium-ion battery is heated at the timing when the lithium precipitation amount increases, and the increase in the lithium precipitation amount is appropriately suppressed, so that the lithium-ion battery can be used in a safe and highly efficient manner. In particular, the battery management unit of the present invention is suitable for large-scale power storage facilities where the temperature distribution is likely to expand.

[0215] (2) The sensor unit 30 includes a temperature sensor 31 that detects the battery temperature of the lithium-ion battery. The battery control device 140 may be configured to heat the battery module BM by the heater device HM when the lithium precipitation amount increases beyond a predetermined threshold value and the battery temperature becomes equal to or lower than a predetermined low temperature threshold value. Also according to this, the lithium-ion battery can be used in a safe and highly efficient manner.

[0216] (Modification of the Third Embodiment) In the third embodiment, the battery management unit BMU of the large-capacity power storage system BSS has been described in detail. However, the battery management unit BMU is not the same as the one described above, and may be partially different from the one described above.

[0217] Also, the technical matters described in the third embodiment are applicable to devices and systems other than the large-capacity power storage system BSS. The battery management unit BMU can be diverted, for example, to the power management of a moving body such as a vehicle.

[0218] In the third embodiment, the heating element is configured by the heater device HM. However, the present invention is not limited to this, and the heating element may be configured by a load device around the battery. Also, the heating element may be configured to be heated by power supply from outside the battery module BM.

[0219] Here, the lithium precipitation amount tends to increase when the battery temperature is low and the charging rate is high, and tends to decrease when the battery temperature is high and the charging rate is low. Thus, there is a certain correlation between the lithium precipitation amount, the charging rate, and the battery temperature. For this reason, the precipitation amount detection unit 37 may calculate the lithium precipitation amount by referring to a control map defining the correlation between the lithium precipitation amount, the charging rate, and the battery temperature, as shown in FIG. 33, for example. This also applies to embodiments other than the present embodiment.

[0220] (Fourth Embodiment) Next, the fourth embodiment will be described with reference to FIGS. 34 and 35. In this embodiment, a battery transport device BSC that houses and transports a battery in a storage container SC will be described.

[0221] Since lithium-ion batteries contain toxic and flammable chemical substances, they need to be transported safely. For example, air transportation has packaging standards regulated by international laws according to the lithium content. Assembled batteries used in electric vehicles have a high lithium content, and air transportation is legally difficult, so sea transportation by ship is common. Compared with air transportation, sea transportation takes a long time. For example, in summer, it may be a long-time transportation in a high-temperature and high-humidity state, or in winter, it may be a long-time transportation in a low-temperature state. In such a stress environment, once a lithium-ion battery transitions to an unsafe state, the lithium-ion battery becomes difficult to control and may cause damage to other cargos and passengers. Therefore, it is important to monitor the safety state of the lithium-ion battery.

[0222] On the other hand, when a lithium-ion battery is transported using a transport container made of a non-combustible material and having a cooling mechanism, and an unsafe event of the battery is detected using the gas sensor 35, it is conceivable to inactivate the lithium-ion battery by the cooling mechanism.

[0223] However, the chemical reaction that leads a lithium-ion battery to an unsafe state is a chain reaction of exothermic reactions. When using the gas sensor 35 for detecting an unsafe event of the battery as in the above method, the chain reaction has already started when gas jets out from the lithium-ion battery. Since the chain reaction progresses rapidly, it is difficult to inactivate the lithium-ion battery at such a time. Further, since the ejected gas is harmful, there is a possibility of damage to the cargo and passengers.

[0224] Taking these into consideration, the battery transport device BSC of the present embodiment monitors factors leading to an abnormal heat generation phenomenon in which the temperature of the battery continues to rise unintentionally, and is configured to be able to detect an abnormal state occurring in the battery at an initial stage of the occurrence of the abnormal heat generation phenomenon based on the monitoring result.

[0225] As shown in FIG. 34, the battery transport device BSC includes a storage container SC that stores a plurality of battery modules BM, a sensor unit 30A that detects the battery state of the plurality of battery modules BM, and an abnormality detection unit 150.

[0226] As shown in FIG. 35, the sensor unit 30A includes a humidity sensor HS and an acceleration sensor GS in addition to the temperature sensor 31, the gas sensor 35, and the deposition amount detection unit 37 described in the first embodiment. The humidity sensor HS is installed inside the storage container SC to detect the humidity inside the storage container SC. The acceleration sensor GS is set in the storage container SC to detect vibrations and impacts applied to the storage container SC. Note that the sensor unit 30A may include other sensors.

[0227] The sensor unit 30A of the present embodiment includes a wireless communication device (not shown) for wireless communication with the abnormality detection unit 150. Note that the sensor unit 30A may include a communication device for wired communication with the abnormality detection unit 150.

[0228] The abnormality detection unit 150 suppresses the occurrence of the abnormal heat generation phenomenon based on the monitoring results of factors leading to the abnormal heat generation phenomenon, detects the abnormal state occurring in the battery at the initial stage of the occurrence of the abnormal heat generation phenomenon, and implements countermeasures against the abnormal heat generation phenomenon based on the detection results of the abnormal state. The abnormality detection unit 150 is configured in the same manner as the monitoring module 50 described in the first embodiment. That is, the abnormality detection unit 150 includes a storage unit 51, a wireless communication unit 52, an internal resistance detection unit 53, a monitoring IC 54, and the like.

[0229] In order to prevent and detect the abnormal heat generation phenomenon at an early stage, the abnormality detection unit 150 executes the control process shown in FIG. 12 described in the first embodiment. In addition, as countermeasures against the abnormal heat generation phenomenon, the abnormality detection unit 150 implements the external notification process, the battery protection process, and the like described in the first embodiment.

[0230] In the external notification process, a signal indicating the occurrence of the abnormal heat generation phenomenon is output to the notification device ND, and the occurrence of the abnormal heat generation phenomenon is notified to the outside through the notification device ND. In this external notification process, for example, it is desirable to notify at least one of the sensor outputs of the temperature sensor 31, the humidity sensor HS, and the acceleration sensor GS and the position information of the battery module BM in which the abnormal heat generation phenomenon has occurred to the outside. The reason is that it becomes easier to clarify the location of responsibility regarding the occurrence of the abnormal heat generation phenomenon. Note that, as the position information of the battery module BM, for example, information specified based on the radio wave intensity of the signal emitted by the sensor unit 30A can be used.

[0231] For the rest, it is the same as the first embodiment. The battery transport device BSC of this embodiment can obtain the same effects as those achieved by the common configuration or equivalent configuration as the first embodiment in the same manner as the first embodiment.

[0232] In addition, the battery transport device BSC of this embodiment has the following features. (1) The battery transport device BSC includes a storage container SC, a factor monitoring unit that monitors factors leading to an abnormal heat generation phenomenon in which the temperature of the battery continues to rise unintentionally, and an abnormality detection unit 150 that detects abnormalities in the battery. Then, the abnormality detection unit 150 suppresses the occurrence of the abnormal heat generation phenomenon based on the monitoring results of the factor monitoring unit, detects the abnormal state occurring in the battery at the initial stage of the occurrence of the abnormal heat generation phenomenon, and implements countermeasures against the abnormal heat generation phenomenon based on the detection results of the abnormal state. According to this, when transporting the battery, it is possible to effectively implement heat countermeasures such as preventing the occurrence of the abnormal heat generation phenomenon and, in the unlikely event that the abnormal heat generation phenomenon occurs, implementing countermeasures from the initial stage of its occurrence.

[0233] (Modification of the Fourth Embodiment) In the fourth embodiment, the battery transport device BSC has been described in detail. However, the battery transport device BSC is not the same as the one described above and may be partially different from the one described above. Also, the technical matters described in the fourth embodiment can be applied to devices and systems other than the battery transport device BSC. (Other Embodiments) As described above, the representative embodiments of the present disclosure have been described. However, the present disclosure is not limited to the above-described embodiments and can be variously modified, for example, as follows.

[0234] In the battery monitoring device 20 of this case, although it is essential to detect the lithium precipitation amount of the lithium-ion battery by the battery monitoring device 20, it is not essential for abnormal heat generation countermeasures of the battery, estimation of the volume ratio SOH of the battery, etc.

[0235] In the above-described embodiments, as factors leading to the abnormal heat generation phenomenon, those that monitor the lithium precipitation amount and the internal resistance of the battery have been exemplified. However, other physical quantities may be monitored as factors leading to the abnormal heat generation phenomenon.

[0236] In the above-described embodiments, a plurality of processes have been exemplified as countermeasures against the abnormal heat generation phenomenon. However, the battery monitoring device 20 may be configured to implement some of these processes. Also, the countermeasures against the abnormal heat generation phenomenon may be processes other than those described above.

[0237] In the above-described embodiment, as abnormal states occurring in the battery at the initial stage of the abnormal heat generation phenomenon, the abnormal internal pressure of the sealed container 11, the abnormal temperature of the battery, the abnormal voltage of the battery, and the abnormal gas in the sealed container 11 are exemplified, but the present invention is not limited thereto. Other battery states may be detected as abnormal states occurring at the initial stage of the abnormal heat generation phenomenon.

[0238] The above-described battery monitoring device 20 includes a flexible printed circuit board FPC and an ASIC circuit, but is not limited thereto. The flexible printed circuit board FPC and the ASIC circuit are not essential components in the battery monitoring device 20.

[0239] As in the above-described embodiment, it is desirable that the battery monitoring device 20 corrects the estimated value of the lithium precipitation amount with the battery temperature or the parasitic resistance value, but it is not necessary to be so.

[0240] As in the above-described embodiment, it is desirable that the battery monitoring device 20 compares a predetermined battery state estimated from the lithium precipitation amount with a predetermined battery state estimated from other elements to diagnose the appropriateness of the precipitation amount detection unit 37, but it is not necessary to be so.

[0241] In the above-described embodiment, an example is given in which the volume ratio SOH is estimated based on the lithium precipitation amount and the thickness of the SEI layer of the battery, but the volume ratio SOH may be estimated based on other physical quantities. The battery monitoring device 20 may, for example, detect a deterioration state including cracking of the positive electrode of the battery and calculate the volume ratio SOH based on the deterioration state.

[0242] As in the above-described embodiments, it is desirable that the battery monitoring device 20 be capable of constituting a battery management system BMS that manages the battery module BM together with the battery management device 60, but it is not necessary for it to be configured in such a manner. This also applies to the charging system BCS and the battery evaluation system BRS. Note that the battery evaluation system BRS may be configured as one functional unit in the battery management system BMS.

[0243] The monitoring target of the battery monitoring device 20 is not limited to the in-vehicle battery mounted on the vehicle. The battery monitoring device 20 can also be used, for example, as a device that monitors a stationary battery or a portable battery.

[0244] The battery monitoring device 20 basically monitors lithium-ion batteries, but is not limited thereto, and any battery that may cause the same problems as lithium-ion batteries can also be a monitoring target. Note that the battery to be monitored by the battery monitoring device 20 does not have to be a modularized unit of a plurality of battery cells C.

[0245] The battery monitoring device 20 may be configured to be connected to the battery ECU 100 by wire instead of wirelessly. The battery monitoring device 20 is not limited to being exactly the same as the one described above, and may be partially different from the one described above.

[0246] In the above-described embodiments, it goes without saying that the elements constituting the embodiments are not necessarily essential, except in cases where it is explicitly stated that they are particularly essential and cases where they are considered to be clearly essential in principle.

[0247] In the above-described embodiments, when numerical values such as the number, numerical value, quantity, range, etc. of the components of the embodiments are mentioned, they are not limited to the specific number, except in cases where it is explicitly stated that they are particularly essential and cases where they are clearly limited to a specific number in principle.

[0248] In the above-described embodiments, when referring to the shape, positional relationship, etc. of components and the like, unless otherwise specifically stated or limited to a specific shape, positional relationship, etc. in principle, they are not limited to such shape, positional relationship, etc.

[0249] The control unit and its method of the present disclosure may be implemented by a dedicated computer provided by configuring a processor and a memory programmed to execute one or more functions embodied by a computer program. The control unit and its method of the present disclosure may be implemented by a dedicated computer provided by configuring a processor with one or more dedicated hardware logic circuits. The control unit and its method of the present disclosure may be implemented by one or more dedicated computers configured by a combination of a processor and a memory programmed to execute one or more functions and a processor configured by one or more hardware logic circuits. Further, the computer program may be stored in a computer-readable non-transitory tangible recording medium as instructions to be executed by a computer.

[0250] [Features of the Present Disclosure] The present disclosure has the following features. [Disclosure 1] A battery monitoring device for monitoring the amount of lithium precipitation in a lithium-ion battery, including a short-circuit circuit (371) that temporarily short-circuits and discharges both ends of the lithium-ion battery, and a precipitation amount detection unit (37) that calculates an estimated value of the lithium precipitation amount based on at least one of the changes in current and voltage when both ends of the lithium-ion battery are short-circuited by the short-circuit circuit; and a temperature sensor (31) that detects the battery temperature of the lithium-ion battery. The precipitation amount detection unit calculates a corrected value obtained by correcting the estimated value with the battery temperature as the lithium precipitation amount.

[0251] [Disclosure 2] A battery monitoring device for monitoring the amount of lithium precipitation in a lithium-ion battery, A short - circuit circuit (371) that temporarily shorts both ends of the lithium - ion battery to discharge it, and a precipitation amount detection unit (37) that calculates an estimated value of the lithium precipitation amount based on at least one of the changes in current and voltage when both ends of the lithium - ion battery are short - circuited by the short - circuit circuit. A storage unit (51) that stores in advance a parasitic resistance value generated between the lithium - ion battery and the short - circuit circuit. The precipitation amount detection unit calculates, as the lithium precipitation amount, a correction value obtained by correcting the estimated value with the parasitic resistance value, a battery monitoring device.

[0252] [Disclosure 3] A temperature sensor (31) that detects the battery temperature of the lithium - ion battery is provided. The precipitation amount detection unit calculates, as the lithium precipitation amount, a correction value obtained by correcting the estimated value using both the parasitic resistance value and the battery temperature, the battery monitoring device according to Disclosure 2.

[0253] [Disclosure 4] The precipitation amount detection unit corrects the parasitic resistance value stored in the storage unit according to the battery temperature, and calculates the lithium precipitation amount using the corrected parasitic resistance value, the battery monitoring device according to Disclosure 3.

[0254] [Disclosure 5] The parasitic resistance value is obtained by connecting to a calibration device having a known impedance before connecting the short - circuit circuit to the lithium - ion battery, the battery monitoring device according to any one of Disclosures 2 to 4.

[0255] [Disclosure 6] A diagnosis unit (541) that compares a predetermined battery state estimated from the lithium precipitation amount with the battery state estimated from other elements other than the lithium precipitation amount to diagnose the suitability of the precipitation amount detection unit is provided, the battery monitoring device according to any one of Disclosures 1 to 5.

[0256] [Disclosure 7] A battery monitoring device for monitoring the amount of lithium deposition in a lithium-ion battery, comprising a short-circuit circuit (371) that temporarily short-circuits both ends of the lithium-ion battery to discharge it, and a deposition amount detection unit (37) that calculates an estimated value of the lithium deposition amount based on at least one change in current and voltage when both ends of the lithium-ion battery are short-circuited by the short-circuit circuit; a diagnosis unit (541) that diagnoses the suitability of the deposition amount detection unit by comparing a predetermined battery state estimated from the lithium deposition amount with the battery state estimated from other elements other than the lithium deposition amount; A battery monitoring device comprising:

[0257] [Disclosure 8] The battery monitoring device according to any one of Disclosures 1 to 7, further comprising a storage medium (51) that stores the temporal change of the lithium deposition amount as one of the usage history or the manufacturing history of the lithium-ion battery.

[0258] [Disclosure 9] A battery monitoring device for monitoring the amount of lithium deposition in a lithium-ion battery, comprising a deposition amount detection unit (37) that calculates the lithium deposition amount using the output of a sensor installed in a storage battery including the lithium-ion battery, and a storage unit (51) that stores the temporal change of the lithium deposition amount as one of the usage history or the manufacturing history of the lithium-ion battery. A battery monitoring device comprising:

[0259] [Disclosure 10] The battery monitoring device according to Disclosure 8 or 9, further comprising an abnormality specifying unit (544) that specifies the cause of the abnormality based on the usage history and the manufacturing history when an abnormality occurs in the lithium-ion battery.

[0260] [Disclosure 11] The battery monitoring device according to any one of Disclosures 1 to 9, wherein when the lithium deposition amount increases beyond a predetermined threshold, the lithium-ion battery is heated by a heating element (HM) that raises the temperature of the lithium-ion battery.

[0261] [Disclosure 12] A battery management unit for managing a storage battery including a lithium - ion battery, a sensor unit (30) for monitoring a battery state including the amount of lithium precipitation in the lithium - ion battery, and a battery control device (140) for performing charge control of the storage battery, wherein the battery control device heats the storage battery by a heating element (HM) that raises the temperature of the storage battery when the amount of lithium precipitation increases beyond a predetermined threshold. A battery management unit.

[0262] [Disclosure 13] The sensor unit includes a temperature sensor (31) for detecting the battery temperature of the lithium - ion battery, and the battery control device heats the storage battery by the heating element when, during the charge control, the amount of lithium precipitation increases beyond a predetermined threshold and the battery temperature becomes equal to or lower than a predetermined low - temperature threshold. The battery management unit according to Disclosure 12.

Explanation of Reference Numerals

[0263] 20 Battery monitoring device 31 Temperature sensor 37 Precipitation amount detection unit 371 Short - circuit circuit

Claims

1. A battery monitoring device for monitoring the amount of lithium deposition in a lithium-ion battery, comprising: a deposition amount detection unit (37) that calculates the amount of lithium deposition using the output of a sensor installed in a storage battery including the lithium-ion battery; a storage unit (51) that stores the temporal change of the amount of lithium deposition as one of the usage histories or one of the manufacturing histories of the lithium-ion battery; an abnormality specifying unit (544) that specifies the cause of the abnormality based on the usage history and the manufacturing history when an abnormality occurs in the lithium-ion battery.

2. The battery monitoring device according to claim 1, wherein when the amount of lithium deposition increases beyond a predetermined threshold, the lithium-ion battery is heated by a heating element (HM) that raises the temperature of the lithium-ion battery.

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