JP7720188B2 - Vehicle battery deterioration determination device - Google Patents

Description

The present invention relates to a vehicle battery deterioration determination device.

Technology has been developed that calculates the degree of deterioration of a vehicle's battery based on information about the battery, and compares the calculated degree of deterioration with a preset threshold to determine the degree of deterioration of the battery.

Japanese Patent Application Laid-Open No. 2020-156217 Japanese Patent Application Laid-Open No. 2020-45782

However, with the above technology, battery degradation is determined using a fixed threshold value regardless of the battery's usage conditions, which can result in unnecessary battery degradation determinations being made, resulting in low accuracy.

The present invention has been made in consideration of the above, and aims to provide a vehicle battery degradation determination device that can accurately determine battery degradation.

In order to solve the above-mentioned problems and achieve the object, the vehicle battery deterioration determination device according to the present invention includes an acquisition unit that acquires battery information used to determine deterioration of a battery mounted on a vehicle, a calculation unit that calculates a degree of deterioration of the battery based on the battery information, a determination unit that determines deterioration of the battery based on whether the degree of deterioration exceeds a threshold value, a selection unit that selects an offset value that corresponds to a use condition that is established in correspondence information that associates each of a plurality of use conditions of the battery with an offset value used to change the threshold value, and an offsetting unit that offsets the battery information based on a value obtained by integrating the offset value selected by the selection unit, and and a change unit that changes the threshold value based on battery information , wherein the plurality of usage conditions include at least two of the following: a mileage of the vehicle, a frequency of electrical loads on the battery, an age of the battery, a first number of intermediate deterioration determinations, a second number of intermediate deterioration determinations, a number of days the vehicle has been left unused, and a temperature of the battery, wherein the first number of intermediate deterioration determinations is the number of times that the voltage of the battery during a predetermined period after a starter of the vehicle has been started has become equal to or less than a first determination threshold value for determining that the battery has deteriorated, and the second number of intermediate deterioration determinations is the number of times that the voltage of the battery during a predetermined period after a starter of the vehicle has been started has become equal to or less than a second determination threshold value that is less than the first determination threshold value .

With this configuration, the threshold value used to determine battery degradation is changed depending on the vehicle battery's usage conditions, preventing the battery from being determined to be degraded even when it is not, enabling highly accurate determination of battery degradation.

In addition, in the vehicle battery deterioration determination device according to the present invention, the multiple usage conditions include gradual battery usage conditions.

This configuration prevents frequent battery degradation determinations.

In addition, in the vehicle battery deterioration determination device according to the present invention, the selection unit and change unit are provided in the vehicle or the server.

With this configuration, by providing a modification unit in the server, there is no need to modify the threshold for each vehicle on the market, making it easier to modify the threshold. Furthermore, by providing a modification unit in the vehicle, it is possible to modify the threshold without using a server.

The vehicle battery degradation determination device of the present invention has the effect of making it possible to determine battery degradation with high accuracy.

FIG. 1 is a diagram showing an example of the overall configuration of a vehicle battery deterioration determination system according to this embodiment. FIG. 2 is a diagram showing an example of the hardware configuration of the data management server and the vehicle included in the vehicle battery deterioration determination system according to this embodiment. FIG. 3 is a diagram for explaining an example of the change over time in the voltage of the battery when the engine of the vehicle is started in the vehicle battery deterioration determination system according to this embodiment. FIG. 4 is a diagram showing an example of the functional configuration of the vehicle and the data management server of the vehicle battery deterioration determination system according to this embodiment. FIG. 5 is a flowchart showing an example of the flow of the battery degradation determination process in the vehicle battery degradation determination system according to this embodiment. FIG. 6 is a flowchart showing an example of the flow of the degradation determination process at the start of use of the battery in the vehicle battery degradation determination system according to this embodiment. FIG. 7 is a flowchart showing an example of the flow of the offset value setting process in the vehicle battery deterioration determination system according to this embodiment. FIG. 8 is a flowchart showing an example of the flow of the threshold value changing process in the vehicle battery deterioration determination system according to this embodiment. FIG. 9 is a diagram for explaining an example of the battery degradation determination process in the vehicle battery degradation determination system according to this embodiment.

Below, an example of an embodiment of a vehicle battery degradation determination system that employs the vehicle battery degradation determination device of the present invention is described in detail with reference to the drawings.

Figure 1 is a diagram showing an example of the overall configuration of a vehicle battery deterioration determination system according to this embodiment. First, using Figure 1, we will explain an example of the overall configuration of a vehicle battery deterioration determination system 1 according to this embodiment.

As shown in FIG. 1, the vehicle battery degradation determination system 1 according to this embodiment includes a data management server 2 (an example of a server), a vehicle 3 (an example of a vehicle), a dealer terminal 4, and a user terminal 5. The data management server 2, vehicle 3, dealer terminal 4, and user terminal 5 are connected to each other so as to be able to communicate with each other via a network NT such as the Internet.

Vehicle 3 transmits vehicle information to data management server 2 via network NT. Here, vehicle information is information related to vehicle 3, including battery information related to the battery 35 (see Figure 2) installed in vehicle 3. Here, battery information is information used to determine deterioration of battery 35.

The data management server 2 receives vehicle information from the vehicle 3. The data management server 2 then calculates the degree of deterioration of the battery 35 based on the battery information included in the received vehicle information. The data management server 2 then determines the deterioration of the battery 35 based on whether the calculated degree of deterioration exceeds a threshold, and transmits the resulting deterioration determination result to the dealer terminal 4 via the network NT. The data management server 2 also changes the threshold used to determine the deterioration of the battery 35 depending on the usage conditions of the battery 35. In this embodiment, the data management server 2 functions as an example of a vehicle battery deterioration determination device.

In this embodiment, the data management server 2 transmits the deterioration assessment result to the dealer terminal 4, but this is not limited to this, and the deterioration assessment result may be transmitted directly to the user terminal 5 without going through the dealer terminal 4. Also, in this embodiment, the data management server 2 performs the deterioration assessment of the battery 35 and changes the threshold value, but this is not limited to this, and at least one of the deterioration assessment of the battery 35 and the change of the threshold value may be performed in the vehicle 3. When the deterioration assessment of the battery 35 is performed in the vehicle 3, the data management server 2 may transmit the threshold value change result to the vehicle 3.

The dealer terminal 4 receives the deterioration assessment result of the battery 35 from the data management server 2. Based on the received deterioration assessment result, the dealer terminal 4 then notifies the user terminal 5 of the user of the vehicle 3 to prompt them to replace the battery 35, etc.

Figure 2 is a diagram showing an example of the hardware configuration of a data management server and a vehicle included in a vehicle battery deterioration determination system according to this embodiment. Next, an example of the hardware configuration of the data management server 2 and vehicle 3 will be described using Figure 2.

As shown in FIG. 2, the vehicle 3 includes an ECU (Electronic Control Unit) 31, an engine 32, a starter 33, an alternator 34, a battery 35, an electrical load 37, a current sensor 38, etc.

Vehicle 3 is an automobile powered by an engine 32. The engine 32 is accompanied by a starter 33 for cranking the engine 32 and an alternator 34 for generating electricity through the rotation of the engine 32. Vehicle 3 is also equipped with a battery 35. Battery 35 may be, for example, a lead-acid battery with a nominal voltage of 12 V. Battery 35 is not limited to a lead-acid battery.

When the engine 32 starts, voltage is applied to the starter 33 from the battery 35 via the power line 36. A flywheel is held by the crankshaft of the engine 32, and when voltage is applied to the starter 33, the plunger of the starter 33 moves and the starter gear of the starter 33 meshes with the flywheel of the engine 32.

Furthermore, when a relay built into the starter 33 is turned on and the current supplied to the starter 33 from the battery 35 increases, the starter 33 inputs a large torque to the engine 32. The engine 32 is cranked by this torque. While the engine 32 is being cranked, the spark plug of the engine 32 is sparked, causing the engine 32 to start.

In addition, the voltage of the battery 35 is applied to electrical loads 37 such as the wiper motor, headlights, air conditioner, and audio equipment installed in the vehicle 3.

The alternator 34 includes a rotor, a stator, and an IC (Integral Circuit) regulator. The rotor rotates in conjunction with the rotation of the crankshaft of the engine 32. A field coil (rotor coil) is provided on the rotor. When a field current (excitation current) is supplied from the IC regulator to the field coil of the rotating rotor, three-phase AC current flows through the stator coil provided on the stator due to electromagnetic induction. The three-phase AC current is rectified to DC voltage by a rectifier. The alternator 34 outputs DC power as generated power, and this generated power is supplied to the battery 35 via the power supply line 36, charging the battery 35.

The ECU 31 provided in the vehicle 3 includes a microcontroller (microcontroller). The microcontroller includes, for example, a central processing unit (CPU) 31a and memory 31b. The memory 31b includes read-only memory (ROM), random access memory (RAM), data flash (flash memory), and the like. While only one ECU 31 is shown in Figure 2, the vehicle 3 is equipped with multiple ECUs with a similar configuration to the ECU 31 to control various parts. The multiple ECUs, including the ECU 31, are connected to enable two-way communication using the CAN (controller area network) communication protocol.

A current sensor 38 is connected to the ECU 31 and is provided in relation to the negative terminal of the battery 35. The current sensor 38 is capable of distinguishing between the charging current flowing through the negative terminal of the battery 35 and the discharging current flowing through the negative terminal of the battery 35. The terminal voltage (battery voltage) of the battery 35 is also input to the ECU 31. Furthermore, although not shown, various sensors such as an accelerator sensor, engine rotation sensor, and throttle opening sensor are connected to the ECU 31.

Here, the accelerator sensor is a sensor that outputs a detection signal corresponding to the amount of accelerator pedal operation. The engine rotation sensor is a sensor that outputs a detection signal in the form of a pulse signal synchronized with the rotation of the crankshaft of the engine 32. The throttle opening sensor is a sensor that outputs a detection signal corresponding to the opening of the electronic throttle valve (throttle opening) of the engine 32.

The ECU 31 controls the engine 32's electronic throttle valve, injectors, spark plugs, starter 33, etc. based on information obtained from detection signals from various sensors and various information input from other ECUs. In this way, the ECU 31 starts, stops, and adjusts the output of the engine 32.

The ECU 31 also acquires the current values of the charging current and discharging current based on the detection signal of the current sensor 38. Next, the ECU 31 calculates the charge amount and discharge amount of the battery 35 by integrating the acquired current values of the charging current and discharging current. Furthermore, the ECU 31 calculates the remaining battery capacity, which is the remaining charge of the battery 35, by integrating the charge amount and discharge amount.

The ECU 31 then controls power generation by the alternator 34 based on the remaining battery charge. When the ECU 31 calculates the remaining battery charge, the calculated remaining battery charge is updated and stored in memory 31b. Furthermore, the ECU 31 calculates the SOC (State of Charge), which indicates the ratio of the remaining battery charge to the charge capacity of the battery 35.

Figure 3 is a diagram illustrating an example of the change in battery voltage over time when the vehicle engine 32 is started using the vehicle battery deterioration determination system according to this embodiment. In Figure 3, the vertical axis represents the voltage of the battery 35, and the horizontal axis represents time. Here, we will use Figure 3 to explain an example of the change in battery voltage over time when the engine 32 is started.

When starting the engine 32, the ECU 31 outputs a starter signal (from off to on) that turns on the starter relay provided on the power supply path of the starter 33, and voltage is applied from the battery 35 to the starter 33. When the plunger of the starter 33 moves and the relay built into the starter 33 turns on, the current supplied from the battery 35 to the starter 33 increases, causing the battery voltage of the battery 35 to drop sharply (time T1). Thereafter, the battery voltage begins to rise and repeatedly fluctuates up and down while the engine 32 is cranked by the torque from the starter 33.

In this embodiment, the ECU 31 acquires the minimum battery voltage value VBSTA during a predetermined period after the starter 33 is started, for example, from the output of the starter signal until the battery voltage begins to fluctuate due to cranking of the engine 32, for use in the battery 35 degradation determination process described below.

In this embodiment, the ECU 31 acquires the minimum value VBSTA each time the engine 32 is started. The ECU 31 then compares the acquired minimum value VBSTA with a first determination threshold V1 used in a first intermediate deterioration determination process for the battery 35 and a second determination threshold V2 used in a second intermediate deterioration determination process for the battery 35. Details of the first intermediate deterioration determination process and the second intermediate deterioration determination process will be described later.

Returning to Figure 2, the data management server 2 includes a CPU 21, ROM 22, RAM 24, HDD (Hard Disk Drive) 25, and communication I/F (Interface) 26.

The communication I/F 26 controls communication with external devices such as the vehicle 3, dealer terminal 4, and user terminal 5 via the network NT. The HDD 25 is an example of a storage medium that stores various programs and data.

The ROM 22 is an example of a storage medium that stores various programs. The RAM 24 functions as a work area when the CPU 21 executes various programs. The CPU 21 is an example of a processor, and performs various processes such as determining deterioration of the battery 35 of the vehicle 3 and changing the threshold value used to determine deterioration of the battery 35.

Figure 4 is a diagram showing an example of the functional configuration of a vehicle and a data management server of a vehicle battery degradation determination system according to this embodiment. Next, using Figure 4, an example of the functional configuration of the data management server 2 and vehicle 3 of the vehicle battery degradation determination system 1 according to this embodiment will be described.

In this embodiment, the vehicle 3 realizes the communication unit 301 by having the CPU 31a execute various programs stored in the memory 31b, etc. In this embodiment, the vehicle 3 realizes various functional units such as the communication unit 301 by having the CPU 31a execute various programs, but this is not limited to this, and the various functional units can also be realized by hardware.

The communication unit 301 transmits vehicle information to the data management server 2 via the network NT. Here, the vehicle information includes the battery voltage of the battery 35, the current value of the current flowing through the battery 35, the temperature of the battery 35 (e.g., the temperature of the battery fluid in the battery 35), the SOC (State of Charge) of the battery 35, the starting status of the engine 32 of the vehicle 3, the starting status of the ECU 31, etc.

In addition, when determining whether the battery 35 has deteriorated within the vehicle 3, the communication unit 301 receives a threshold value from the data management server 2. In this case, the vehicle 3 can also use the received threshold value to determine whether the battery 35 has deteriorated.

In this embodiment, the data management server 2 implements a communication unit 311, an estimation unit 312, an acquisition unit 313, a calculation unit 314, a determination unit 315, a selection unit 316, and a change unit 317 by having the CPU 21 use the RAM 24 as a working area and execute various programs stored in the ROM 22, HDD 25, etc.

In this embodiment, the data management server 2 realizes various functional units such as a communication unit 311, an estimation unit 312, an acquisition unit 313, a calculation unit 314, a determination unit 315, a selection unit 316, and a change unit 317 by having the CPU 21 execute various programs, but this is not limited to this, and these various functional units can also be realized by hardware.

The communication unit 311 receives vehicle information from vehicles 3 on the market via the communication I/F 26. The communication unit 311 also transmits the deterioration determination result of the battery 35 to the dealer terminal 4 or the user terminal 5 via the communication I/F 26. Furthermore, when determining deterioration of the battery 35 within the vehicle 3, the communication unit 311 may transmit a threshold value used to determine deterioration of the battery 35 to the vehicle 3.

The estimation unit 312 acquires the battery voltage and current values of the battery 35 and the discharge current flowing through the negative terminal of the battery 35 contained in the received vehicle information, and obtains the battery voltage and current values during cranking of the engine 32. The estimation unit 312 then applies a Kalman filter to the acquired battery voltage and current values, etc., to estimate the internal resistance, which is an example of an internal parameter of the battery 35.

The estimation unit 312 also estimates the OCV (Open Circuit Voltage) of the battery 35 based on the battery voltage of the battery 35. In this embodiment, the estimation unit 312 estimates the battery voltage when the engine 32 is not started as the OCV.

The acquisition unit 313 acquires battery information used to determine deterioration of the battery 35. In this embodiment, the acquisition unit 313 acquires battery information such as the internal resistance and OCV estimated by the estimation unit 312, and the SOC and temperature included in the vehicle information. The acquisition unit 313 then stores big data aggregating battery information for vehicles 3 on the market in a database realized by a storage device such as the HDD 25.

The calculation unit 314 calculates the deterioration level, which is the degree of deterioration of the battery 35, based on the battery information stored in the HDD 25. In this embodiment, the calculation unit 314 calculates the deterioration level of the battery 35 based on battery information (e.g., internal resistance, OCV, SOC, temperature) of the vehicle 3 for which the deterioration determination of the battery 35 is performed. Here, the internal resistance and OCV of the battery 35 vary depending on the SOC and temperature of the battery 35, etc. For example, the internal resistance of the battery 35 tends to increase as the temperature at which the SOC is 100% decreases. Therefore, in this embodiment, the data management server 2 stores a deterioration level table that associates, for each combination of the SOC and temperature of the battery 35, the internal resistance and OCV with the deterioration level of the battery 35 corresponding to the internal resistance and OCV. The calculation unit 314 then calculates the deterioration level of the battery 35 as the deterioration level associated with the internal resistance and OCV acquired by the acquisition unit 313 in the deterioration level table corresponding to the combination of SOC and temperature acquired by the acquisition unit 313.

The determination unit 315 determines the deterioration of the battery 35 based on whether the deterioration level calculated by the calculation unit 314 exceeds a preset threshold. In this embodiment, the determination unit 315 determines the deterioration of the battery 35 each time the engine 32 starts. Then, the determination unit 315 determines that the battery 35 is deteriorated when the deterioration level of the battery 35 exceeds the threshold a preset number of times (e.g., five times) consecutively.

The determination unit 315 also sets the internal resistance and OCV of the battery 35 when the engine 32 is started for the first time after the battery 35 is installed in the vehicle 3 as the initial values of the internal resistance and OCV of the battery 35 when the SOH (State Of Health) of the battery 35 is 100%. The determination unit 315 then determines that the battery 35 has deteriorated if the difference between the latest values and the initial values, which are the internal resistance and OCV of the battery 35 at an initial time (for example, a predetermined period after the battery 35 is installed in the vehicle 3), is equal to or greater than a predetermined value. Here, the latest values are the internal resistance and OCV estimated in the most recent trip. The trip refers to the time from when the ignition was turned on (when the engine 32 was started).

In addition, the determination unit 315 executes a first intermediate deterioration determination process and a second intermediate deterioration determination process for the battery 35 based on the battery voltage of the battery 35 when the engine 32 is started.

Here, the first intermediate degradation determination process determines whether the minimum battery voltage value VBSTA is equal to or less than the first determination threshold V1, and counts the number of times that the minimum value VBSTA is equal to or less than the first determination threshold V1 (hereinafter referred to as the first intermediate degradation determination count). Here, the first determination threshold V1 is the battery voltage threshold at which it is determined that the battery 35 is degraded.

The second intermediate degradation determination process determines whether the minimum battery voltage value VBSTA is equal to or less than the second determination threshold V2, and counts the number of times the minimum value VBSTA is equal to or less than the second determination threshold V2 (hereinafter referred to as the second intermediate degradation determination count). The second determination threshold V2 is the battery voltage threshold at which use of the battery 35 is stopped.

The selection unit 316 selects an offset value associated with the established battery 35 usage conditions from an offset value table that associates each of a plurality of battery 35 usage conditions with an offset value used to change the threshold. The change unit 317 changes the threshold based on the selected offset value. This changes the threshold used to determine the deterioration of the battery 35 in accordance with the usage conditions of the battery 35 of each vehicle 3, making it possible to prevent the battery 35 from being determined to be deteriorated even when it is not. As a result, the determination unit 315 can determine the deterioration of the battery 35 with high accuracy.

Here, the battery 35 usage conditions include, for example, the vehicle 3's mileage, electrical load frequency, battery age, first intermediate deterioration determination count, second intermediate deterioration determination count, number of days the vehicle has been left unattended, and battery temperature. The electrical load frequency is the average frequency of application of battery voltage to the electrical load 37 per day over a preset number of days of use (e.g., 50 days). The battery age is the number of years the battery 35 has been in use. The vehicle unattended days is the number of days the vehicle 3 has been left unattended without being used. The battery temperature is the temperature of the battery 35 when the vehicle 3 is in use.

Here, the use conditions are the use conditions of the battery 35 for which the threshold is changed. For example, the use conditions may be any of the use conditions (1) to (7) shown in Table 1 below.

Usage condition (1) is that the vehicle 3 has traveled 50,000 km or more. Furthermore, usage condition (2) is that the electrical load frequency is 60%/50 days or more. Furthermore, usage condition (3) is that the battery has been in use for 5 years or more.

Furthermore, usage condition (4) is that the first intermediate deterioration determination count is 100 or more. Furthermore, usage condition (5) is that the second intermediate deterioration determination count is 80 or more. In other words, the multiple usage conditions may include gradual usage conditions for the battery 35. This can prevent frequent determinations of battery 35 deterioration. Furthermore, usage condition (6) is that the vehicle has been left unattended for 30 days or more. Usage condition (7) is that the battery temperature is 30°C or higher.

The offset value table is correspondence information that associates each of a plurality of use conditions with an offset value used to change the threshold value. In this embodiment, the offset value table is a table that associates use conditions (1) to (7) with offset values of the internal resistance and OCV of the battery 35, as shown in Table 2 below.

In this embodiment, the change unit 317 offsets the battery information (e.g., at least one of the internal resistance and the OCV) acquired by the acquisition unit 313 based on the offset value selected by the selection unit 316, and changes the threshold value based on the offset battery information. The change unit 317 may also offset the battery information based on a value obtained by integrating the offset value associated with the established usage conditions, and change the threshold value based on the offset battery information.

In this embodiment, the offset value may be a value set in stages. Furthermore, the offset value may differ for each attribute of the vehicle 3, such as the grade and model of the vehicle. Furthermore, the offset value may be set based on the big data of the attributes of the vehicle 3 for which the threshold is to be changed, among the big data stored in a storage device such as the HDD 25.

This allows the threshold to be changed to reflect the deterioration trends of the batteries 35 of vehicles 3 on the market. Furthermore, since it becomes easier to collect battery information used to change the threshold, the development man-hours required to change the threshold can be reduced. Furthermore, by changing the threshold on the data management server 2, it is no longer necessary to change the threshold for each vehicle 3, making threshold changes more efficient. Furthermore, the offset value may be changeable as needed depending on the usage status of the battery 35.

In this embodiment, the selection unit 316 and the change unit 317 are provided in the data management server 2, which is an example of a server. This eliminates the need to change the threshold for each vehicle 3 in the market for each vehicle, making it easier to change the threshold. In this case, when determining the deterioration of the battery 35 in each vehicle 3, the vehicle 3 downloads the changed threshold from the data management server 2 and uses the downloaded threshold to determine the deterioration of the battery 35. The selection unit 316 and the change unit 317 may also be provided in the vehicle 3. This makes it possible to change the threshold without using the data management server 2.

Figure 5 is a flowchart showing an example of the flow of the battery degradation determination process in the vehicle battery degradation determination system according to this embodiment. Next, using Figure 5, we will explain an example of the flow of the battery degradation determination process for the battery 35 in the vehicle battery degradation determination system 1 according to this embodiment.

The estimation unit 312 determines whether the engine 32 is running based on the engine 32 start state indicated by the vehicle information received by the communication unit 311 (step S501). If the engine 32 is not running (step S501: No), the estimation unit 312 determines whether the ECU 31 is running (step S502).

Next, the estimation unit 312 determines whether a predetermined time (e.g., 6 hours) has elapsed since the engine 32 was not started and the ECU 31 was activated (step S503). If the predetermined time has not elapsed since the engine 32 was not started and the ECU 31 was activated (step S503: No), the estimation unit 312 returns to step S503.

On the other hand, if the engine 32 has not started and a predetermined time has elapsed since the ECU 31 was activated (step S503: Yes), the estimation unit 312 determines that the OCV of the battery 35 has stabilized and estimates the OCV of the battery 35 based on the battery voltage included in the received vehicle information (step S504). The estimation unit 312 then stores the estimated OCV in a storage device such as the HDD 25 (step S505).

If the engine 32 is started (step S501: Yes), the estimation unit 312 determines whether this is the first start of the engine 32 during one trip of the vehicle 3 (step S506). If this is the second or subsequent start of the engine 32 during one trip of the vehicle 3 (step S506: No), the CPU 21 does not determine the deterioration of the battery 35 and ends the deterioration determination process for the battery 35.

On the other hand, if this is the first start of the engine 32 during one trip of the vehicle 3 (step S506: Yes), the estimation unit 312 acquires the battery voltage and current values of the battery 35 discharge current during cranking of the engine 32 from the battery voltage and current values of the battery 35 contained in the received vehicle information (step S507). Next, the estimation unit 312 applies a Kalman filter to the acquired battery voltage and current values, etc., to estimate the internal resistance of the battery 35 (step S508).

The acquisition unit 313 acquires battery information including the internal resistance and OCV estimated by the estimation unit 312, and the SOC, temperature, etc. included in the vehicle information received from the vehicle 3, and stores (preserves) the acquired battery information in a database such as the HDD 25 (step S509). The calculation unit 314 then calculates the degree of deterioration of the battery 35 based on the internal resistance, OCV, SOC, temperature, etc. included in the acquired battery information (step S510).

Next, the determination unit 315 determines whether the calculated deterioration level exceeds the threshold value (step S511). If the calculated deterioration level exceeds the threshold value (step S511: Yes), the determination unit 315 increments the battery deterioration count number n by 1 (step S512). Furthermore, the determination unit 315 determines whether the count number n is equal to or greater than a preset count number (e.g., 5 times) (step S513). If the count number n is less than the preset count number (step S513: No), the determination unit 315 determines that the battery 35 is not deteriorated.

On the other hand, if the count number n is equal to or greater than the preset count number (step S513: Yes), the determination unit 315 determines that the battery 35 is degraded. The internal resistance of the battery 35 varies depending on the OCV, temperature, SOC, etc. of the battery 35, which causes variations in the calculation results of the degree of degradation. Therefore, in this embodiment, the determination unit 315 determines that the battery 35 is degraded if the count number of the degree of degradation of the battery 35 is equal to or greater than a preset threshold value consecutively. This improves the accuracy of determining the degradation of the battery 35. The communication unit 311 then notifies the dealer terminal 4 of the degradation determination result of the battery 35 via the communication I/F 26 (step S514).

Conventional vehicle battery degradation determination systems can only detect battery 35 degradation when the vehicle 3 is inspected, and cannot detect battery 35 degradation without waiting for inspection. However, the vehicle battery degradation determination system 1 of this embodiment makes it possible to determine battery 35 degradation when the vehicle 3's engine 32 is started. As a result, even if the battery 35 has deteriorated before the vehicle 3 is inspected, it is possible to drive the vehicle while making the most of the battery 35's performance.

If the calculated deterioration level does not exceed the threshold value (step S511: No), the determination unit 315 determines that the battery 35 has not deteriorated and resets the count number n (step S515).

Figure 6 is a flowchart showing an example of the flow of the degradation determination process at the start of battery use in the vehicle battery degradation determination system according to this embodiment. Next, using Figure 6, we will explain an example of the flow of the degradation determination process at the start of use of the battery 35 in the vehicle battery degradation determination system 1 according to this embodiment.

First, the determination unit 315 determines whether this is the first start of the engine 32 after the battery 35 is installed in the vehicle 3 (step S601). If this is the first start of the engine 32 after the battery 35 is installed in the vehicle 3 (step S601: Yes), the determination unit 315 sets the internal resistance and OCV of the battery 35 when the engine 32 is first started after the battery 35 is installed in the vehicle 3 to the initial values of the internal resistance and OCV of the battery 35 when the SOH of the battery 35 is 100% (step S602).

On the other hand, if this is not the first time the engine 32 has been started since the battery 35 was installed in the vehicle 3 (step S601: No), the determination unit 315 calculates the difference between the latest value and the initial value of the internal resistance and OCV of the battery 35 (step S603). Here, the latest value is the internal resistance and OCV estimated in the most recent trip. In this embodiment, the latest value is the battery information stored in a database such as the HDD 25 in S509 of FIG. 5. Also, as described above, a trip indicates the period from when the ignition was turned on (starting of the engine 32). Then, the determination unit 315 determines whether the calculated difference value is equal to or greater than a preset value (step S604). If the calculated difference value is equal to or greater than the preset value (step S604: Yes), the determination unit 315 determines that the battery 35 has deteriorated. On the other hand, if the calculated difference value is less than the preset value (step S604: No), the determination unit 315 determines that the battery 35 has not deteriorated.

Figure 7 is a flowchart showing an example of the flow of the offset value setting process in the vehicle battery deterioration determination system 1 according to this embodiment. Next, using Figure 7, we will explain an example of the flow of the offset value setting process in the vehicle battery deterioration determination system 1 according to this embodiment.

The change unit 317 acquires battery information such as the internal resistance, OCV, SOC, and temperature of the battery 35 of a vehicle 3 on the market (step S701). Furthermore, the change unit 317 acquires battery information for the battery 35 of a vehicle 3 whose battery 35 has actually deteriorated (step S702).

Then, the change unit 317 sets offset values associated with each usage condition in the offset value table based on the battery information of the batteries 35 of vehicles 3 on the market and the battery information of the degraded batteries 35 (step S703).

Figure 8 is a flowchart showing an example of the flow of the threshold value change process in the vehicle battery deterioration determination system 1 according to this embodiment. Next, using Figure 8, we will explain an example of the flow of the threshold value change process in the vehicle battery deterioration determination system 1 according to this embodiment.

First, the selection unit 316 determines whether at least one of the multiple usage conditions for the battery 35 of the vehicle 3 is met (step S801). If none of the multiple usage conditions for the battery 35 is met (step S801: No), the change unit 317 does not change the threshold.

On the other hand, if at least one of the multiple usage conditions of the battery 35 is met (step S801: Yes), the selection unit 316 changes the threshold value based on the offset values of the internal resistance and OCV associated with the met usage condition in the offset value table (step S802).

Figure 9 is a diagram illustrating an example of the battery degradation determination process in the vehicle battery degradation determination system according to this embodiment. In Figure 9, the vertical axis represents the internal resistance of the battery 35, and the horizontal axis represents time. Next, using Figure 9, an example of the threshold value change process in the vehicle battery degradation determination system 1 according to this embodiment will be described.

For example, as shown in FIG. 9, if the degree of degradation based on the internal resistance of the battery 35 exceeds the threshold value five consecutive times from time t1 to time t5, the determination unit 315 determines that the battery 35 has degraded. Also, as shown in FIG. 9, if the usage condition (4) of the battery 35 is met at time t-2, the change unit 317 offsets the internal resistance based on the offset value associated with the usage condition (4) in the offset value table, and changes the threshold value based on the offset internal resistance.

Also, as shown in FIG. 9, if usage condition (5) of battery 35 is met at time t-1, the change unit 317 offsets the internal resistance based on the offset value associated with usage condition (5) in the offset value table, and changes the threshold value based on the offset internal resistance.

In this way, the vehicle battery deterioration determination system 1 according to this embodiment selects an offset value associated with the established battery 35 usage conditions in the offset value table, and changes the threshold value based on the selected offset value. This changes the threshold value used to determine the deterioration of the battery 35 in accordance with the usage conditions of the battery 35 of each vehicle 3, thereby preventing the battery 35 from being determined to be deteriorated even when it is not. As a result, it becomes possible to determine the deterioration of the battery 35 with high accuracy.

Furthermore, with the vehicle battery degradation determination system 1 according to this embodiment, by setting multiple usage conditions as tiered usage conditions for the battery 35, it is possible to prevent frequent determinations of battery 35 degradation. Furthermore, with the vehicle battery degradation determination system 1 according to this embodiment, by providing the selection unit 316 and the change unit 317 in the data management server 2, it is no longer necessary to change the threshold for each vehicle 3 on the market, making it easier to change the threshold. Furthermore, with the vehicle battery degradation determination system 1 according to this embodiment, by providing the selection unit 316 and the change unit 317 in the vehicle 3, it is possible to change the threshold without using the data management server 2.

REFERENCE SIGNS LIST 1 Vehicle battery deterioration determination system 2 Data management server 3 Vehicle 4 Dealer terminal 5 User terminal 21, 31a CPU
22 ROM
24 RAM
25 HDDs
26 Communication I/F
31 ECU
31b Memory 32 Engine 33 Starter 34 Alternator 35 Battery 36 Power supply line 37 Electric load 38 Current sensor 301, 311 Communication unit 312 Estimation unit 313 Acquisition unit 314 Calculation unit 315 Determination unit 316 Selection unit 317 Change unit NT Network

Claims (2)

an acquisition unit that acquires battery information used to determine deterioration of a battery mounted on a vehicle;
a calculation unit that calculates a deterioration level of the battery based on the battery information;
a determination unit that determines deterioration of the battery based on whether the deterioration level exceeds a threshold;
a selector that selects an offset value associated with a use condition that is established in correspondence information that associates each of a plurality of use conditions of the battery with an offset value used to change the threshold;
a change unit that offsets the battery information based on a value obtained by integrating the offset value selected by the selection unit, and changes the threshold value based on the offset battery information;
Equipped with
the plurality of usage conditions include at least two of a mileage of the vehicle, a frequency of electrical loads on the battery, an age of the battery, a first number of intermediate deterioration determinations, a second number of intermediate deterioration determinations, a number of days the vehicle has been left unused, and a temperature of the battery;
the first intermediate deterioration determination count is the number of times that the voltage of the battery becomes equal to or lower than a first determination threshold voltage for determining that the battery is deteriorated during a predetermined period after a starter of the vehicle is started,
The second intermediate deterioration determination count is the number of times that the voltage of the battery during a predetermined period after the starter of the vehicle is started falls below a second determination threshold that is less than the first determination threshold . The vehicle battery deterioration determination device according to claim 1 , wherein the selection unit and the change unit are provided in the vehicle or a server.