Battery diagnosis system, battery diagnosis method, and battery diagnosis program

Abstract

In the present invention, a data acquisition unit acquires battery data including the voltage and current of a secondary battery which is contained in a battery pack (30) mounted on an electric mobility (1). A consumption speed calculation unit calculates the consumption speed of the secondary battery on the basis of the battery data. A speed change amount calculation unit calculates an amount of change in the consumption speed of the secondary battery. When the consumption speed of the secondary battery has increased to a setting value or more, a diagnostic unit refers to predetermined information and diagnoses the cause of the increase in the consumption speed.

Description

Battery diagnostic system, battery diagnostic method, and battery diagnostic program

[0001] The present disclosure relates to a battery diagnostic system, a battery diagnostic method, and a battery diagnostic program for diagnosing a battery pack mounted on an electric mobility vehicle.

[0002] Electric mobility devices such as electric bicycles and electric motorcycles use detachable, portable, and replaceable battery packs. During the battery pack warranty period, electric mobility users may suddenly notice that their battery packs are consuming electricity more quickly and request a replacement due to a quality defect. However, at one battery manufacturer, approximately 60% of the battery packs returned to the quality control department are in good condition, resulting in unnecessary costs for inspection and transportation of non-defective products.

[0003] When a battery pack is used in a low-temperature environment, its internal resistance increases and its discharge capacity decreases. Furthermore, if the tire pressure of an electric mobility vehicle is low, the distance it can travel with the same discharge capacity decreases. These factors are not due to poor quality or deterioration of the battery pack; the former will be resolved when the temperature rises, and the latter will be resolved by adding air to the tires. If users could learn the reason for the rapid battery consumption before returning a battery pack, it is expected that the return rate of normal battery packs would decrease significantly.

[0004] Patent Document 1 discloses a method for determining deterioration of a secondary battery by calculating the ratio X:dQ / dV of the rate of change dQ / dt of the charge quantity of a secondary battery to the rate of change dV / dt of the voltage, comparing the calculated ratio X with a reference value Xref, and determining deterioration of the secondary battery based on the comparison result. Patent Document 1 determines deterioration of the secondary battery, but cannot identify whether accelerated consumption of the battery pack is due to factors other than deterioration.

[0005] Patent Document 2 discloses a method for estimating the lifespan of a battery used in a sensor unit that measures the condition of a tire based on the discharge capacity of the battery. Patent Document 2 predicts the lifespan of the battery in the sensor unit, but does not predict the lifespan of a battery pack used as a power source for electric mobility.

[0006] International Publication No. 11 / 121692 Japanese Patent Application Laid-Open No. 2022-56921

[0007] The present disclosure has been made in light of these circumstances, and its purpose is to provide a technology for diagnosing the cause of rapid battery consumption in a battery pack mounted on an electric mobility.

[0008] In order to solve the above problem, a battery diagnostic system of one embodiment of the present invention includes a data acquisition unit that acquires battery data including the voltage and current of a secondary battery included in a battery pack installed in an electric mobility vehicle, a consumption rate calculation unit that calculates the consumption rate of the secondary battery based on the battery data, a rate change amount calculation unit that calculates the amount of change in the consumption rate of the secondary battery, and a diagnostic unit that, when the consumption rate of the secondary battery becomes faster than a set value, refers to specified information and diagnoses the cause of the increased consumption rate.

[0009] Any combination of the above components, and conversion of the expression of the present disclosure into an apparatus, system, method, computer program, etc., are also valid aspects of the present disclosure.

[0010] According to the present disclosure, it is possible to diagnose the cause of rapid consumption of a battery pack mounted on an electric mobility.

[0011] Fig. 1 is a diagram for explaining a battery diagnostic system according to an embodiment. Fig. 2 is a diagram showing an example of the configuration of a battery pack according to an embodiment. Fig. 3 is a diagram showing an example of the configuration of a mobile terminal device, a speed sensor, and an air pressure sensor attached to an electric bicycle according to an embodiment. Fig. 4 is a diagram showing an example of the configuration of a battery diagnostic system according to an embodiment. Fig. 5 is a diagram showing a specific image of a method for estimating FCC. Fig. 6 is a flowchart showing the flow of diagnostic processing of a battery pack by a battery diagnostic system according to an embodiment.

[0012] FIG. 1 is a diagram illustrating a battery diagnostic system 10 according to an embodiment. The battery diagnostic system 10 according to the embodiment is a system that diagnoses the condition of a battery pack 30 mounted on an electric bicycle 1. The battery diagnostic system 10 may be constructed, for example, on an in-house server installed in the in-house facility or data center of a business that provides diagnostic services for the battery pack 30. The battery diagnostic system 10 may also be constructed on a cloud server used based on a cloud service. The battery diagnostic system 10 may also be constructed on multiple servers that are distributed across multiple locations (data centers, in-house facilities). The multiple servers may be a combination of multiple in-house servers, a combination of multiple cloud servers, or a combination of an in-house server and a cloud server.

[0013] The electric bicycle 1 is equipped with a detachable, portable, and replaceable battery pack 30. The battery pack 30 is charged while attached to a charging slot of a charger (not shown). The charged battery pack 30 is removed from the charging slot by the user and attached to the attachment slot of the electric bicycle 1.

[0014] The battery pack 30 and the mobile terminal device 20 (hereinafter, assumed to be a smartphone) carried by the user are connected via short-range wireless communication, either directly or via a hand switch fixed to the handle. When connected via the hand switch, the battery pack 30 and the hand switch are connected via a wired connection, and the hand switch and the mobile terminal device 20 are connected via short-range wireless communication. Bluetooth (registered trademark), Wi-Fi (registered trademark), infrared communication, etc. can be used as short-range wireless communication. In the following, in this embodiment, it is assumed that BLE (Bluetooth Low Energy) is used as short-range wireless communication. BLE is an extended standard of Bluetooth and is a low-power short-range wireless communication standard using the 2.4 GHz band.

[0015] The mobile terminal device 20 can access the network 2 to which the battery diagnostic system 10 is connected. The mobile terminal device 20 can access the network 2 via a mobile phone network (4G / 5G) or Wi-Fi.

[0016] Network 2 is a general term for communication paths such as the Internet, dedicated lines, and VPNs (Virtual Private Networks), and the communication media and protocols are not important. Examples of communication media that can be used include wired LANs, wireless LANs, mobile phone networks, optical fiber networks, ADSL networks, and CATV networks. Examples of communication protocols that can be used include TCP (Transmission Control Protocol) / IP (Internet Protocol), UDP (User Datagram Protocol) / IP, and Ethernet (registered trademark).

[0017] 2 is a diagram showing an example of the configuration of a battery pack 30 according to an embodiment. The battery pack 30 includes a battery pack 31 and a battery management device 32. The battery pack 31 includes multiple cells E1-En connected in series. The number of cells connected in series is determined by the load specifications. The main loads of the electric bicycle 1 are the motor and the inverter.

[0018] The cells can be lithium-ion battery cells, nickel-metal hydride battery cells, lead battery cells, etc. In the following description, we will assume an example in which lithium-ion battery cells (nominal voltage: 3.6-3.7 V) are used. Note that in each series stage of cells, multiple cells may be connected in parallel to increase capacity.

[0019] A switch SW1 for switching between electrical continuity with the load or charger is inserted in the power line connecting the battery pack 31 and the load or charger. A semiconductor switch or a relay can be used as the switch SW1.

[0020] The battery management device 32 includes a measurement unit 33, a control unit 34, a wireless communication unit 35, an antenna 35a, and a non-volatile memory unit 36. The measurement unit 33 is configured with an AFE (Analog Front End) IC or an ASIC (Application Specific Integrated Circuit). The control unit 34 is configured with a microcontroller. The non-volatile memory unit 36 ​​can be an EEPROM (Electrically Erasable Programmable Read Only Memory) or a NAND flash memory.

[0021] The measurement unit 33 is connected to each node of the multiple cells E1-En connected in series by multiple voltage measurement lines, and measures the voltage of each cell E1-En by measuring the voltage between each two adjacent voltage measurement lines.

[0022] The measurement unit 33 includes a multiplexer and an A / D converter. The multiplexer outputs the voltages of the multiple cells E1-En to the A / D converter in a predetermined order. The A / D converter converts the analog voltages input from the multiplexer into digital values. The measurement unit 33 transmits the voltage values ​​of the cells E1-En, converted into digital values, to the control unit 34 via a serial communication interface.

[0023] The measurement unit 33 measures the current flowing through the battery pack 31. A shunt resistor Rs is connected to a power line connecting the battery pack 31 to a load or a charger. A differential amplifier (not shown) amplifies the voltage across the shunt resistor Rs and outputs it to an A / D converter in the measurement unit 33. The A / D converter converts the analog voltage indicating the current flowing through the battery pack 31, which is input from the differential amplifier, into a digital value. The measurement unit 33 transmits the current value converted into a digital value to the control unit 34 via a serial communication interface.

[0024] A temperature sensor T1 (e.g., a thermistor) is installed on the surface of the battery pack 31. A divided voltage between the temperature sensor T1 and a voltage dividing resistor (not shown) is input to a measurement unit 33. An A / D converter in the measurement unit 33 converts the input analog voltage indicating the temperature into a digital value. The measurement unit 33 transmits the converted digital temperature value to the control unit 34 via a serial communication interface.

[0025] The control unit 34 manages the states of the cells E1-En based on the voltage values ​​of the cells E1-En, the current values ​​flowing through the battery pack 31, and the temperature values ​​of the battery pack 31 received from the measurement unit 33. When the control unit 34 detects overcharging, overdischarging, overcurrent, high temperature abnormality, or low temperature abnormality, it sends a shut-off signal for the switch SW1 to the measurement unit 33 to turn off the switch SW1. When a voltage difference between the cells E1-En that exceeds a set value occurs, the control unit 34 determines that a cell balance abnormality has occurred, and sends a shut-off signal for the switch SW1 to the measurement unit 33 to turn off the switch SW1.

[0026] The control unit 34 estimates the SOC (State Of Charge) by combining the OCV method and the current integration method. The OCV method is a method for estimating the SOC based on the OCV, which is based on the measured cell voltage, and the SOC-OCV curve of the cell. The SOC-OCV curve of the cell is created in advance by the battery manufacturer based on characteristic tests and is registered in the control unit 34 at the time of shipment.

[0027] The current integration method is a method for estimating the SOC based on the OCV at the start of charging and discharging the cell and the integrated value of the measured current. With the current integration method, current measurement errors accumulate as the charging and discharging time increases. Therefore, it is preferable to use a weighted average of the SOC estimated by the current integration method and the SOC estimated by the OCV method.

[0028] The control unit 34 stores battery data including the cell voltage, current, temperature, and SOC of the battery pack 30 in the non-volatile memory unit 36 ​​at a predetermined storage period (for example, every one minute). As the cell voltage, the voltage values ​​of all the cells E1-En may be stored, or only the maximum cell voltage and the minimum cell voltage may be stored.

[0029] The wireless communication unit 35 performs signal processing for short-range wireless communication. The wireless communication unit 35 pairs with the mobile terminal device 20 and transmits battery data stored in the non-volatile memory unit 36 ​​via short-range wireless communication. In this embodiment, the wireless communication unit 35 is configured as a BLE module, and the antenna 35a is configured as a chip antenna or a pattern antenna built into the BLE module. Note that when the battery pack 30 and the mobile terminal device 20 are connected via a hand switch, the wireless communication unit 35 is omitted from the battery pack 30 and instead is mounted in the hand switch. The battery pack 30 and the mobile terminal device 20 are connected via a wired connection.

[0030] 3 is a diagram showing an example configuration of a mobile terminal device 20, a speed sensor 40 attached to an electric bicycle 1, and an air pressure sensor 50 according to an embodiment. The mobile terminal device 20 is a terminal device carried by the user of the electric bicycle 1. The user downloads an application program for managing the electric bicycle 1 (hereinafter referred to as a bicycle app) from a distribution server to the mobile terminal device 20 and installs it on the mobile terminal device 20. The bicycle app is uploaded to the distribution server in advance, and the distribution server provides the bicycle app it manages to mobile terminal devices 20 that access the server via network 2.

[0031] The mobile terminal device 20 includes a GPS sensor 21, an inertial sensor 22, an operation display unit 23, a control unit 24, a recording medium 25, a first antenna 26a, and a second antenna 26b.

[0032] The GPS sensor 21 is an example of a GNSS (Global Navigation Satellite System) receiver, and detects the current location information of the mobile terminal device 20 in terms of latitude, longitude, and altitude, and outputs the detected location information to the control unit 24. Specifically, the GPS sensor 21 receives radio waves, including their respective transmission times, from a plurality of GPS satellites, and calculates the latitude, longitude, and altitude of the reception point based on the plurality of transmission times included in the plurality of received radio waves.

[0033] The inertial sensor 22 may be, for example, a three-axis gyro sensor and a three-axis acceleration sensor, which detect angular velocity and acceleration in the X, Y, and Z directions applied to the three-axis gyro sensor and the three-axis acceleration sensor and output the results to the control unit 24 .

[0034] The operation display unit 23 includes a touch panel display such as a liquid crystal display, an organic EL display, or a mini LED display, and displays an image input from the control unit 24. The operation display unit 23 also accepts operations from the user and outputs an operation signal to the control unit 24 according to the content of the user's operation.

[0035] The control unit 24 includes a travel distance calculation unit 241, a first wireless communication unit 242a, a second wireless communication unit 242b, and a display control unit 243. The control unit 24 is realized by a combination of hardware resources and software resources, or by hardware resources alone. Examples of hardware resources that can be used include a CPU, ROM, RAM, GPU (Graphics Processing Unit), NPU (Neural Network Processing Unit), ASIC, FPGA (Field Programmable Gate Array), and other LSIs. Examples of software resources that can be used include programs such as an operating system, middleware, and applications.

[0036] The recording medium 25 is a large-capacity non-volatile recording medium, and is configured with a built-in flash memory (e.g., a NAND flash memory). Some models also allow for the addition of an external semiconductor memory card. Various programs and data are recorded on the recording medium 25.

[0037] The speed sensor 40 is attached to the wheel of the electric bicycle 1. The speed sensor 40 includes a sensor unit 41, a control unit 42, and an antenna 43. The sensor unit 41 magnetically or optically measures the number of rotations of the tire and outputs the number of rotations to the control unit 42. The control unit 42 connects to the mobile terminal device 20 via short-range wireless communication (e.g., Bluetooth) using the antenna 43, and transmits the number of rotations of the tire measured by the sensor unit 41 to the mobile terminal device 20 in real time.

[0038] The speed sensor 40 may be connected to a cycle computer (not shown) mounted on the handlebars of the electric bicycle 1 via wired or short-range wireless communication (e.g., ANT+ (registered trademark) or Bluetooth). In this case, the control unit 42 of the speed sensor 40 transmits the tire rotation speed measured by the sensor unit 41 to the cycle computer in real time. The cycle computer is connected to the mobile terminal device 20 via short-range wireless communication (e.g., Bluetooth). The cycle computer transmits the tire rotation speed received from the speed sensor 40 to the mobile terminal device 20 in real time or in batches.

[0039] The air pressure sensors 50 are attached to the air valves of the front and rear tires of the electric bicycle 1. The air pressure sensors 50 include a sensor unit 51, a control unit 52, and an antenna 53. The sensor unit 51 measures the tire air pressure and outputs it to the control unit 52. The control unit 52 uses the antenna 53 to connect to the mobile terminal device 20 via short-range wireless communication (e.g., Bluetooth), and transmits the tire air pressure measured by the sensor unit 51 to the mobile terminal device 20 in real time.

[0040] The tire pressure sensor 50 may be connected to the cycle computer via short-range wireless communication (e.g., ANT+ or Bluetooth). In this case, the control unit 52 of the tire pressure sensor 50 transmits the tire pressure measured by the sensor unit 51 to the cycle computer in real time. The cycle computer is connected to the mobile terminal device 20 via short-range wireless communication (e.g., Bluetooth). The cycle computer transmits the tire pressure received from the tire pressure sensor 50 to the mobile terminal device 20 in real time or in batches.

[0041] The first wireless communication unit 242a of the mobile terminal device 20 uses the first antenna 26a to access the network 2 via a mobile phone network (4G / 5G) or Wi-Fi, and connects to the battery diagnostic system 10. The second wireless communication unit 24ba uses the second antenna 26b to connect to the battery pack 30, the speed sensor 40, and the tire pressure sensor 50 via Bluetooth.

[0042] The user of the electric bicycle 1 operates the operation display unit 23 to register the vehicle type in a bicycle app installed on the mobile terminal device 20. The bicycle app identifies the tire circumference of the registered vehicle type. If the tire circumference of the registered vehicle type is unknown, the bicycle app displays a tire size input field on the operation display unit 23 and prompts the user to input the tire size. The bicycle app converts the input tire size into circumference.

[0043] The traveling distance calculation unit 241 calculates the traveling distance of the electric bicycle 1 by multiplying the circumference of the tire by the number of tire rotations received from the speed sensor 40. The traveling distance calculation unit 241 saves the traveling distance for each day in the recording medium 25 at a predetermined saving interval (for example, every minute). The traveling distance calculation unit 241 calculates the speed of the electric bicycle 1 by dividing the traveling distance by a unit time.

[0044] In addition, if a speed sensor 40 is not installed on the electric bicycle 1, the mileage calculation unit 241 can estimate the mileage and speed of the electric bicycle 1 based on the movement trajectory of the position of the electric bicycle 1 detected by the GPS sensor 21.

[0045] The display control unit 243 can display at least one of the travel distance and speed for each day on the operation display unit 23. The display control unit 243 can display on the operation display unit 23 a map on which the current position of the electric bicycle 1 detected by the GPS sensor 21 is superimposed.

[0046] The tire pressure monitoring unit (not shown) stores the tire pressure obtained from the tire pressure sensor 50 in the recording medium 25 at a predetermined interval (for example, every minute). The tire pressure monitoring unit outputs an alert when the obtained tire pressure falls below a lower limit or exceeds an upper limit. When an air pressure alert is output, the display control unit 243 displays an alert message indicating an abnormal tire pressure on the operation display unit 23.

[0047] When the user of the electric bicycle 1 launches the bicycle app on the portable terminal device 20 while the Bluetooth of the portable terminal device 20 is on, a connection is established between the second wireless communication unit 242b of the portable terminal device 20 and the wireless communication unit 35 of the battery pack 30.

[0048] When a connection is established with the mobile terminal device 20, the control unit 34 of the battery pack 30 transmits the battery data stored in the non-volatile memory unit 36 ​​to the mobile terminal device 20 via the wireless communication unit 35. The mobile terminal device 20 transmits the battery data received from the second wireless communication unit 242b, as well as the mileage data and tire pressure data for the corresponding period stored in the recording medium 25, to the battery diagnosis system 10 via the network 2.

[0049] When the control unit 34 of the battery pack 30 transmits battery data to the battery diagnostic system 10 via the mobile terminal device 20, it erases the transmitted battery data from the non-volatile memory unit 36. When the control unit 24 of the mobile terminal device 20 transmits mileage data and tire pressure data to the battery diagnostic system 10, it erases the transmitted mileage data and tire pressure data from the recording medium 25. In this way, each time the bicycle app on the mobile terminal device 20 is launched, the battery data, mileage data, and tire pressure data recorded between the previous launch and the current launch are transmitted to the battery diagnostic system 10.

[0050] 4 is a diagram showing an example of the configuration of a battery diagnostic system 10 according to an embodiment. The battery diagnostic system 10 includes a control unit 11, a storage unit 12, and a communication unit 13. The communication unit 13 is an external communication interface (e.g., a network interface card (NIC)) for connecting to the network 2 via a wired or wireless connection.

[0051] The control unit 11 includes a data acquisition unit 111, a consumption rate calculation unit 112, a rate change amount calculation unit 113, a State of Health (SOH) estimation unit 114, a charge / discharge amount calculation unit 115, a diagnosis unit 116, and a notification control unit 117. The functions of the control unit 11 can be realized by a combination of hardware resources and software resources, or by hardware resources alone. Examples of hardware resources that can be used include a CPU, ROM, RAM, GPU, NPU, ASIC, FPGA, and other LSIs. Examples of software resources that can be used include an operating system, an application, and other programs.

[0052] The storage unit 12 includes a non-volatile recording medium such as a hard disk drive (HDD) or a solid state drive (SSD), and stores various data. The storage unit 12 includes a battery and vehicle data holding unit 121.

[0053] The data acquisition unit 111 acquires battery data of the battery pack 30 and mileage data and air pressure data of the electric bicycle 1 from the mobile terminal device 20 via the network 2. The data acquisition unit 111 stores the acquired battery data, mileage data, and air pressure data in the battery and vehicle data storage unit 121.

[0054] The consumption rate calculation unit 112 calculates the consumption rate of the battery pack 31 based on the battery data and the mileage data. In this embodiment, the consumption rate of the battery pack 31 is defined as the ratio between the mileage of the electric bicycle 1 and the SOC decrease amount of the battery pack 31. This ratio may be defined as the SOC decrease amount per unit mileage, or may be defined as the mileage distance per unit SOC decrease amount.

[0055] The consumption rate of the battery pack 31 may also be determined by the amount of SOC decrease of the battery pack 31 when traveling a predetermined route on the electric bicycle 1. The predetermined route is set to a route that the user regularly takes, such as from home to work, from work to home, from home to school, or from school to home.

[0056] If the mobile terminal device 20 can acquire location information of the home, workplace, or school of the user of the electric bicycle 1, and time-series location data of the electric bicycle 1 detected by the GPS sensor 21, the consumption speed calculation unit 112 can calculate the amount of SOC decrease in the battery pack 31 when the electric bicycle 1 travels a specified route.

[0057] The rate change amount calculation unit 113 calculates the amount of change in the consumption rate of the battery pack 31 calculated by the consumption rate calculation unit 112. The amount of change in the consumption rate of the battery pack 31 may be specified by the change over time in the consumption rate of the battery pack 31, by the ratio of the consumption rate to an initial value, or by the change over time of the ratio of the consumption rate to the initial value.

[0058] The SOH estimation unit 114 estimates the SOH of each cell, the minimum voltage cell, or the assembled battery 31 using the two-point OCV method. The SOH is defined as the ratio of the current FCC to the initial FCC, with a lower value (closer to 0%) indicating more advanced deterioration. When estimating the SOH of the assembled battery 31, the SOH estimation unit 114 sums up the cell voltages of the multiple series-connected cells E1-En contained in the battery data to estimate the voltage of the assembled battery 31.

[0059] The SOH estimation unit 114 calculates the SOC difference (ΔSOC) between the SOC in the first rest state and the SOC in the second rest state based on the voltage of the cell or battery pack 31 in the first rest state, the voltage of the cell or battery pack 31 in the second rest state, and the SOC-OCV curve of the cell or battery pack 31. The SOH estimation unit 114 calculates the current integrated value (= charge / discharge capacity) Q for the period between the first rest state and the second rest state based on the current value included in the battery data. The SOH estimation unit 114 calculates the current full charge capacity (FCC) of the cell or battery pack 31 based on the current integrated value Q and ΔSOC. The SOH estimation unit 114 calculates the SOH based on the current FCC and initial FCC of the cell or battery pack 31.

[0060] 5 is a diagram showing a specific image of the FCC estimation method. The SOH estimation unit 114 identifies two voltages, the first rest state and the second rest state, and sets these as the OCVs at two points. The SOH estimation unit 114 references the SOC-OCV curve to identify SOC1 and SOC2 corresponding to OCV1 and OCV2, respectively, and calculates ΔSOC between SOC1 and SOC2 and the current integrated value Q.

[0061] The SOH estimation unit 114 calculates the following (Equation 1) to estimate the FCC: FCC=Q / ΔSOC (Equation 1)

[0062] The SOH estimation unit 114 estimates the SOH by calculating the following (Equation 2): SOH=current FCC / initial FCC×100 (Equation 2)

[0063] Returning to Fig. 4, the charge / discharge amount calculation unit 115 calculates the cumulative charge amount Qc and discharge amount Qd for a certain period (for example, one week) based on the time-series data of current included in the battery data.

[0064] When the consumption rate of the battery pack 31 becomes faster than a set value, the diagnosis unit 116 refers to predetermined information and diagnoses the cause of the increased consumption rate. The notification control unit 117 transmits a message including the cause of the increased consumption rate to the mobile terminal device 20, and controls the mobile terminal device 20 to notify the user of the electric bicycle 1 of the message.

[0065] The diagnosis unit 116 refers to the temperature included in the battery data and diagnoses whether the increased consumption rate of the battery pack 31 is due to use at low temperatures. In a lithium-ion battery, the movement of lithium ions slows down at low temperatures, causing the voltage to drop. That is, at low temperatures, the internal resistance increases, causing a voltage drop. Therefore, even when discharging at the same discharge rate, the lower the temperature, the faster the discharge end voltage is reached, and the less available discharge capacity is available. From the user's perspective, this appears to be a faster consumption of the battery pack 30.

[0066] If it is determined that the increased consumption rate of the battery pack 31 is due to use at low temperatures, the notification control unit 117 sends a message to the mobile terminal device 20 indicating that the battery pack 30 is consuming faster due to the low temperatures, and a message indicating that the battery pack 30 itself is normal.

[0067] The diagnosis unit 116 refers to the air pressure data and diagnoses whether the increased consumption rate of the battery pack 31 is caused by a drop in air pressure in the tires of the electric bicycle 1. The lower the tire air pressure, the greater the tire rolling resistance, and the lower the electricity consumption of the electric bicycle 1.

[0068] If it is determined that the increased consumption rate of the battery pack 31 is due to a drop in tire air pressure, the notification control unit 117 sends a message to the mobile terminal device 20 indicating that the battery pack 30 is being consumed faster due to the drop in tire air pressure, and a message recommending that the tire be inflated.

[0069] The diagnosis unit 116 refers to the SOH of the battery pack 31 and diagnoses whether the increased consumption rate of the battery pack 31 is caused by deterioration of the battery pack 31. As deterioration of the battery pack 31 progresses, the available discharge capacity decreases.

[0070] Deterioration of the cell or battery pack 31 is classified as normal deterioration or abnormal deterioration. Normal deterioration does not require return, but abnormal deterioration requires return or contacting the support center. The diagnosis unit 116 diagnoses abnormal deterioration when the deviation of the SOH of the cell or battery pack 31 from the deterioration curve of the cell or battery pack 31 is equal to or greater than a predetermined value. The deterioration curve of the cell or battery pack 31 may be a prepared one, or may be generated by regressing the SOH.

[0071] In the latter case, the diagnosis unit 116 performs curve regression using a plurality of sample data of SOH calculated in a time series for the cell or battery pack 31, to generate a degradation regression curve for the cell or battery pack 31. For example, the least squares method can be used for the curve regression. It is known that cell degradation progresses in proportion to the square root of time (0.5 power law), as shown in the following (Equation 3). The diagnosis unit 116 uses 0.5 power exponential curve regression, with time t as the independent variable and SOH as the dependent variable, to calculate the degradation coefficient w in the above (Equation 3). １ Ask for. w ０ is common and is usually set in the range of 1.0 to 1.1. ０ +w １ √t...(Formula 3) w ０ is the initial value, w １ is the degradation coefficient.

[0072] If it is determined that the increased consumption rate of the battery pack 31 is caused by normal deterioration of the battery pack 31, the notification control unit 117 transmits to the mobile terminal device 20 a message that the battery pack 30 is being consumed faster due to deterioration, and a message that the deterioration is due to specifications. If it is determined that the increased consumption rate of the battery pack 31 is caused by abnormal deterioration of the battery pack 31, the notification control unit 117 transmits to the mobile terminal device 20 a message that the battery pack 30 is being consumed faster due to deterioration, and a message urging the user to replace the battery pack 30 or contact a support center.

[0073] The diagnosis unit 116 diagnoses whether the increased consumption rate of the battery pack 31 is due to leakage current by referring to the charge amount Qc and discharge amount Qd over a certain period of time. The charge amount Qc and discharge amount Qd of the battery pack 31 over a certain period of time should basically match. Strictly speaking, the discharge amount Qd becomes slightly less than the charge amount Qc due to the influence of self-discharge and the like. If the discharge amount Qd is less than the charge amount Qc by more than a certain value or a certain ratio, there is a high possibility that leakage current is flowing within the battery pack 30 due to poor insulation of the circuit within the battery pack 30 or a micro-short circuit of a cell included in the battery pack 31.

[0074] The certain period is preferably a period between two points where the same conditions are met (for example, the remaining battery charge is the same). For example, starting from a certain fully charged state of the battery pack 30 in use, the total charge / discharge amounts are compared at the next or subsequent full charge states. If the battery pack 30 is normal during that period, the total discharge amount and the total charge amount will be approximately equal. However, if there is leakage current due to a circuit abnormality, a discharge amount that cannot be detected by the measuring unit 31 in the battery pack 30 will occur, and the total charge amount will be calculated to be greater than the total discharge amount.

[0075] If it is determined that the increased consumption rate of the battery pack 31 is due to leakage current, the notification control unit 117 sends a message to the mobile terminal device 20 stating that leakage current may be causing the battery pack 30 to consume more quickly, and a message urging the user to contact the support center.

[0076] 6 is a flowchart showing the flow of diagnostic processing for the battery pack 30 by the battery diagnostic system 10 according to the embodiment. The consumption rate calculation unit 112 calculates the consumption rate of the battery pack 31 (considered as the discharge rate Vd in the flowchart of FIG. 6 ) based on the battery data and the travel distance data (S10). The speed change amount calculation unit 113 calculates the ratio Vd / Vd0 of the discharge rate Vd (discharge amount ΔQ / travel distance ΔL) to the initial value Vd0 (S11).

[0077] The diagnosis unit 116 compares the initial value ratio Vd / Vd0 of the discharge rate Vd with an abnormality determination threshold (e.g., 0.8) (S12). If the initial value ratio Vd / Vd0 of the discharge rate Vd is greater than the abnormality determination threshold (N in S12), the notification control unit 117 transmits a message to the mobile terminal device 20 indicating that the battery pack 30 is normal (S26).

[0078] If the ratio Vd / Vd0 of the initial value of the discharge rate Vd is equal to or less than the abnormality determination threshold (Y in S12), the diagnosis unit 116 calculates a temperature-corrected discharge rate Vdc based on the discharge rate Vd, the temperature-specific discharge characteristic map, and the temperature included in the battery data (S13). The temperature-specific discharge characteristic map is a map created by measuring the discharge capacity-voltage characteristics of the cells included in the battery pack 31 by temperature in advance.

[0079] The diagnosis unit 116 refers to a discharge characteristic map for each temperature and calculates the amount of discharge capacity reduction due to the effects of low temperature based on the discharge capacity-voltage characteristics at the measured temperature and the discharge capacity-voltage characteristics at room temperature (e.g., 20°C). The diagnosis unit 116 corrects the discharge amount ΔQ based on the battery data using the amount of discharge capacity reduction due to the effects of low temperature, and estimates the discharge amount ΔQ' at room temperature. The diagnosis unit 116 calculates the temperature-corrected discharge speed Vdc based on the assumed discharge amount ΔQ' at room temperature and the mileage ΔL. The speed change amount calculation unit 113 calculates the ratio Vdc / Vd0 of the temperature-corrected discharge speed Vdc to the initial value Vd0 (S14).

[0080] The diagnosis unit 116 compares the initial value ratio Vdc / Vd0 of the temperature-corrected discharge rate Vdc with the abnormality determination threshold (S15). If the initial value ratio Vdc / Vd0 of the temperature-corrected discharge rate Vdc is greater than the abnormality determination threshold (N in S15), the notification control unit 117 transmits to the mobile terminal device 20 a message indicating that the battery pack 30 is being consumed faster due to the low temperature and a message indicating that the battery pack 30 is normal (S16, S26). If the temperature-corrected discharge rate Vdc is normal, no other abnormalities are diagnosed.

[0081] If the ratio Vdc / Vd0 of the initial value of the temperature-corrected discharge rate Vdc is equal to or less than the abnormality determination threshold (Y in S15), the diagnosis unit 116 compares the measured tire pressure with the pressure warning determination threshold (S17). If the measured tire pressure is below the pressure warning determination threshold (N in S17), the notification control unit 117 sends a message to the mobile terminal device 20 indicating that the battery pack 30 is being consumed more quickly due to a drop in tire pressure (S18). If the measured tire pressure is equal to or greater than the pressure warning determination threshold (Y in S17), the process of step S18 is skipped. Note that, assuming that tire pressure cannot be quantitatively corrected, diagnosis of other abnormalities is also performed regardless of whether a warning is issued.

[0082] The SOH estimation unit 114 estimates the SOH of the battery pack 31 based on the battery data (S19). The charge / discharge amount calculation unit 115 calculates the ratio Qd / Qc of the discharge amount Qd to the charge amount Qc over a certain period based on the time-series data of current included in the battery data (S20).

[0083] The diagnosis unit 116 compares the calculated SOH with a degradation determination threshold (e.g., 50%) (S21). If the calculated SOH is below the degradation determination threshold (N in S21), the notification control unit 117 transmits a message to the mobile terminal device 20 indicating that the battery pack 30 is being consumed more quickly due to degradation (S22). If the calculated SOH is equal to or greater than the degradation determination threshold (Y in S21), the process of step S22 is skipped.

[0084] The diagnosis unit 116 compares the calculated charge / discharge ratio Qd / Qc with the leakage current determination threshold (S23). If the calculated charge / discharge ratio Qd / Qc is below the leakage current determination threshold (N in S23), the notification control unit 117 transmits a message to the mobile terminal device 20 indicating that the battery pack 30 may be consumed faster due to leakage current (S24). If the calculated charge / discharge ratio Qd / Qc is equal to or greater than the leakage current determination threshold (Y in S23), the process of step S24 is skipped. The charge / discharge ratio may be defined as Qd / (Qc+Qd).

[0085] The notification control unit 117 transmits a message to the mobile terminal device 20 describing a countermeasure for each cause (S25). If it is determined that the cause of the increased consumption rate of the battery pack 30 is due to a drop in tire air pressure, the notification control unit 117 transmits a message to the mobile terminal device 20 recommending that the tire be inflated. If it is determined that the cause of the increased consumption rate is due to deterioration of the battery pack 30, the notification control unit 117 transmits a message to the mobile terminal device 20 urging the replacement of the battery pack 30. If it is determined that the cause of the increased consumption rate is due to leakage current, the notification control unit 117 transmits a message to the mobile terminal device 20 urging the mobile terminal device 20 to contact a support center. Even if the cause of the increased consumption rate cannot be identified, the notification control unit 117 transmits a message to the mobile terminal device 20 urging the mobile terminal device 20 to contact a support center.

[0086] Since two or more symptoms may coexist in the tire pressure determination in step S17, the SOH determination in step S21, and the leakage current determination in step S23, even if one abnormality is detected, the remaining abnormality determinations are also executed. Furthermore, the order of the three abnormality determinations is arbitrary and is not limited to the order shown in FIG. 6.

[0087] As described above, according to this embodiment, the cause of the rapid consumption of the battery pack 30 mounted on the electric bicycle 1 can be diagnosed while the battery pack 30 is in the user's possession. If the battery pack 30 can be determined to be normal when the user feels it, the rate of battery packs 30 returned to the manufacturer can be significantly reduced. This can also reduce unnecessary costs associated with inspecting and transporting normal products.

[0088] By defining the battery pack 30 consumption rate in terms of distance rather than time, it is possible to monitor the battery pack 30 consumption rate based on the user's experience. This makes it possible to distinguish between factors related to the battery pack 30 itself, factors related to the vehicle (such as low tire pressure), and discrepancies in the user's experience due to assumptions. This leads to efficient problem solving for both users and battery manufacturers.

[0089] The present disclosure has been described above based on the embodiments. The embodiments are merely examples, and it will be understood by those skilled in the art that various modifications are possible in the combination of the respective components and processing steps, and that such modifications are also within the scope of the present disclosure.

[0090] When the battery diagnostic system 10 can acquire time-series position information, including altitude, of the electric bicycle 1 detected by the GPS sensor 21 from the mobile terminal device 20, the consumption rate calculation unit 112 can estimate the gradient of the route traveled by the electric bicycle 1. The gradient of the route traveled by the electric bicycle 1 may be estimated based on time-series latitude and longitude information detected by the GPS sensor 21 and map data. The consumption rate calculation unit 112 corrects the discharge current at each sampling point to the discharge current when the gradient is zero based on the estimated gradient of the traveled route, and then calculates the SOC depletion amount. When the consumption rate of the battery pack 31 is determined by the SOC depletion amount when traveling a predetermined route that is regularly used, the gradient factor can be removed from the factors that change the consumption rate.

[0091] In the above-described embodiment, the electric bicycle 1 is assumed to be the electric mobility device equipped with the battery pack 30, but it may also be an electric motorcycle, an electric kick scooter, or a micro EV. In the above-described embodiment, the mobile terminal device 20 is assumed to be a smartphone, but it may also be any device that can access the network 2, such as a cycle computer or a smart watch.

[0092] The diagnostic function of the battery pack 30 executed by the battery diagnostic system 10 described above may be incorporated into the control unit 34 in the battery pack 30. In this case, the control unit 34 of the battery pack 30 acquires the tire rotation speed and tire air pressure via short-range wireless communication from the mobile terminal device 20 or the cycle computer.

[0093] The embodiment may be specified by the following items.

[0094] [Item 1] A battery diagnostic system (10) comprising: a data acquisition unit (111) that acquires battery data including the voltage and current of a secondary battery (31) included in a battery pack (30) mounted on an electric mobility (1); a consumption rate calculation unit (112) that calculates the consumption rate of the secondary battery (31) based on the battery data; a rate change amount calculation unit (113) that calculates the amount of change in the consumption rate of the secondary battery (31); and a diagnosis unit (116) that, when the consumption rate of the secondary battery (31) becomes faster than a set value, diagnoses the cause of the increased consumption rate by referring to predetermined information. This makes it possible to diagnose the cause of the increased consumption rate of the secondary battery (31). [Item 2] The battery diagnostic system (10) according to Item 1 further comprises a notification control unit (117) that controls to notify a user of the electric mobility (1) of a message including the cause of the increased consumption rate of the secondary battery (31). This allows the user to recognize the cause of the increased consumption rate of the secondary battery (31) and prompts them to take appropriate action according to the cause. [Item 3] The battery diagnostic system (10) according to Item 1 or 2, wherein the data acquisition unit (111) acquires battery data including the voltage, current, and temperature of the secondary battery (31), and the diagnosis unit (116) refers to the temperature to diagnose whether the increased consumption rate of the secondary battery (31) is due to use at a low temperature. This makes it possible to diagnose whether the increased consumption rate of the secondary battery (31) is due to low temperature. [Item 4] The battery diagnostic system (10) according to Item 1 or 2, wherein the data acquisition unit (111) further acquires air pressure data of tires of the electric mobility (1), and the diagnosis unit (116) refers to the air pressure data to diagnose whether the increased consumption rate of the secondary battery (31) is due to a drop in air pressure in the tires. This makes it possible to diagnose whether the increased consumption rate of the secondary battery (31) is due to a drop in tire pressure.[Item 5] The battery diagnostic system (10) according to Item 1 or 2, further comprising an SOH estimation unit (114) that estimates the SOH (State Of Health) of the secondary battery (31) based on the battery data, and the diagnosis unit (116) diagnoses whether an increase in the consumption rate of the secondary battery (31) is caused by deterioration of the secondary battery (31) by referring to the SOH. This makes it possible to diagnose whether an increase in the consumption rate of the secondary battery (31) is caused by deterioration of the secondary battery (31). [Item 6] The battery diagnostic system (10) according to Item 5, wherein the diagnosis unit (116) diagnoses abnormal deterioration when a deviation of the SOH from a deterioration curve of the secondary battery (31) is equal to or greater than a predetermined value. This makes it possible to classify deterioration of the secondary battery (31) into normal deterioration and abnormal deterioration. [Item 7] The battery diagnostic system (10) according to Item 1 or 2, further comprising a charge / discharge amount calculation unit (115) that calculates a charge amount and a discharge amount over a certain period based on the battery data, and the diagnosis unit (116) diagnoses whether a leakage current is the cause of an increase in the consumption rate of the secondary battery (31) by referring to the charge amount and the discharge amount over the certain period. This makes it possible to diagnose whether a leakage current is the cause of an increase in the consumption rate of the secondary battery (31). [Item 8] The battery diagnostic system (10) according to Item 1, wherein the consumption rate calculation unit (112) defines the consumption rate of the secondary battery (31) as a ratio between a traveling distance of the electric mobility (1) and a decrease in the SOC (State Of Charge) of the secondary battery (31). This makes it possible to monitor the consumption rate of the secondary battery (31) based on a user's experience. [Item 9] The battery diagnosis system (10) according to Item 1, wherein the consumption rate calculation unit (112) defines the consumption rate of the secondary battery (31) as a decrease in State Of Charge (SOC) of the secondary battery (31) when the electric mobility (1) travels a predetermined route. This makes it possible to eliminate road-related factors such as gradients from factors that cause changes in the consumption rate.[Item 10] The battery diagnostic system (10) according to Item 1, wherein the rate change amount calculation unit (113) defines the rate of change in the consumption rate of the secondary battery (31) as a change in the consumption rate of the secondary battery (31) over time, a ratio of the consumption rate of the secondary battery (31) to an initial value, or a change in the ratio of the consumption rate of the secondary battery (31) to the initial value over time. This makes it possible to determine whether a change in the consumption rate of the secondary battery (31) is due to specifications or some kind of abnormality. [Item 11] A battery diagnostic method comprising the steps of: acquiring battery data including a voltage and a current of a secondary battery (31) included in a battery pack (30) mounted on an electric mobility (1); calculating the consumption rate of the secondary battery (31) based on the battery data; calculating a rate of change in the consumption rate of the secondary battery (31); and, when the consumption rate of the secondary battery (31) becomes faster than a set value, diagnosing the cause of the increase in the consumption rate by referring to specified information. According to this, it is possible to diagnose the cause of accelerated consumption of a battery pack (30) mounted on an electric mobility (1). [Item 12] A battery diagnostic program that causes a computer to execute the following processes: a process of acquiring battery data including the voltage and current of a secondary battery (31) included in a battery pack (30) mounted on an electric mobility (1); a process of calculating a consumption rate of the secondary battery (31) based on the battery data; a process of calculating an amount of change in the consumption rate of the secondary battery (31); and a process of diagnosing the cause of the accelerated consumption rate by referring to specified information when the consumption rate of the secondary battery (31) becomes faster than a set value. According to this, it is possible to diagnose the cause of the accelerated consumption of a battery pack (30) mounted on an electric mobility (1).

[0095] The present invention can be used to diagnose battery packs installed in electric mobility vehicles.

[0096] REFERENCE SIGNS LIST 1 Electric bicycle, 2 Network, 30 Battery pack, 31 Assembled battery, 32 Battery management device, 33 Measurement unit, 34 Control unit, 35 Wireless communication unit, 35a Antenna, 36 Non-volatile memory unit, E1-En Cell, Rs Shunt resistor, T1 Temperature sensor, SW1 Switch, 10 Battery diagnostic system, 11 Control unit, 111 Data acquisition unit, 112 Consumption rate calculation unit, 113 Speed ​​change amount calculation unit, 114 SOH estimation unit, 115 Charge / discharge amount calculation unit, 116 Diagnosis unit, 117 Notification control unit, 12 Memory unit, 121 Battery / vehicle data storage unit, 13 Communication unit, 20 Portable terminal device, 21 GPS sensor, 22 Inertial sensor, 23 Operation display unit, 24 Control unit, 241 Travel distance calculation unit, 242a First wireless communication unit, 242b Second wireless communication unit, 243 Display control unit, 25 Recording medium, 26a First antenna, 26b Second antenna, 40 Speed ​​sensor, 41 Sensor unit, 42 Control unit, 43 Antenna, 50 Air pressure sensor, 51 Sensor unit, 52 Control unit, 53 Antenna.

Claims

1. A battery diagnostic system comprising: a data acquisition unit that acquires battery data including the voltage and current of a secondary battery included in a battery pack mounted on an electric mobility; a consumption rate calculation unit that calculates the consumption rate of the secondary battery based on the battery data; a rate change amount calculation unit that calculates the amount of change in the consumption rate of the secondary battery; and a diagnostic unit that, when the consumption rate of the secondary battery becomes faster than a set value, refers to specified information and diagnoses the cause of the increased consumption rate.

2. The battery diagnostic system according to claim 1, further comprising a notification control unit that controls the notification of a message including the cause of the increased consumption rate of the secondary battery to a user of the electric mobility.

3. The battery diagnostic system of claim 1 or 2, wherein the data acquisition unit acquires battery data including the voltage, current, and temperature of the secondary battery, and the diagnostic unit refers to the temperature to diagnose whether the increased consumption rate of the secondary battery is due to use at a low temperature.

4. The battery diagnostic system of claim 1 or 2, wherein the data acquisition unit further acquires tire air pressure data of the electric mobility, and the diagnosis unit refers to the air pressure data to diagnose whether the increased consumption rate of the secondary battery is due to a drop in tire air pressure.

5. A battery diagnostic system as described in claim 1 or 2, further comprising an SOH estimation unit that estimates the SOH (State Of Health) of the secondary battery based on the battery data, and the diagnosis unit refers to the SOH to diagnose whether the increased consumption rate of the secondary battery is due to deterioration of the secondary battery.

6. The battery diagnostic system according to claim 5, wherein the diagnostic unit diagnoses abnormal deterioration when the deviation of the SOH from the deterioration curve of the secondary battery is equal to or greater than a predetermined value.

7. A battery diagnostic system as described in claim 1 or 2, further comprising a charge / discharge amount calculation unit that calculates the charge amount and discharge amount over a certain period of time based on the battery data, and the diagnosis unit diagnoses whether the increased consumption rate of the secondary battery is due to leakage current by referring to the charge amount and discharge amount over the certain period of time.

8. The battery diagnostic system according to claim 1, wherein the consumption rate calculation unit defines the consumption rate of the secondary battery as a ratio between a travel distance of the electric mobility and a decrease in the SOC (State Of Charge) of the secondary battery.

9. The battery diagnostic system according to claim 1, wherein the consumption rate calculation unit defines the consumption rate of the secondary battery as the amount of decrease in SOC (State Of Charge) of the secondary battery when the electric mobility travels a predetermined route.

10. The battery diagnostic system of claim 1, wherein the rate change amount calculation unit defines the rate of change in the consumption rate of the secondary battery as a change in the consumption rate of the secondary battery over time, a ratio of the consumption rate of the secondary battery to an initial value, or a change in the ratio of the consumption rate of the secondary battery to an initial value over time.

11. A battery diagnosis method comprising the steps of: acquiring battery data including the voltage and current of a secondary battery included in a battery pack mounted on an electric mobility; calculating the consumption rate of the secondary battery based on the battery data; calculating the amount of change in the consumption rate of the secondary battery; and, when the consumption rate of the secondary battery becomes faster than a set value, diagnosing the cause of the increased consumption rate by referring to specified information.

12. A battery diagnostic program that causes a computer to execute the following processes: a process of acquiring battery data including the voltage and current of a secondary battery included in a battery pack installed in an electric mobility; a process of calculating the consumption rate of the secondary battery based on the battery data; a process of calculating the amount of change in the consumption rate of the secondary battery; and a process of diagnosing the cause of the increase in consumption rate by referring to specified information when the consumption rate of the secondary battery becomes faster than a set value.

Images