Estimation device for estimating battery charging rate

Abstract

To provide a technique for estimating the charging rate of a battery with a simple configuration.SOLUTION: An estimation device for estimating a charging rate of a battery that supplies power to auxiliary equipment mounted on a vehicle, includes: a voltage sensor to detect battery voltage; a temperature sensor to detect battery temperature; and a processing circuit connected to the pressure sensor and the temperature sensor and performing an estimation process to estimate the charging rate of the battery. The estimation process is executed while the vehicle is parked, and estimates the charging rate of the battery based on a detected voltage detected by the voltage sensor and a detected voltage detected by the temperature sensor.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present specification relates to an estimation device that estimates the charging rate of a battery that supplies power to an auxiliary device mounted on a vehicle. [Background technology]

[0002] Patent Document 1 describes an estimation device that estimates the charging rate of a battery. This estimation device includes a voltage sensor that detects the voltage of the battery, and a processing circuit connected to the voltage sensor. The processing circuit creates a data group that indicates the relationship between the voltage (i.e., closed circuit voltage) and the charging rate during charging and discharging, and estimates the charging rate of the battery based on the data group and the detection voltage detected by the voltage sensor. With this configuration, the charging rate of the battery can be accurately estimated while the battery is being charged or discharged. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-163861 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is known that the relationship between the voltage and the charging rate (e.g., SOC: State of Charge) of a battery varies depending on the charging / discharging current of the battery and the temperature of the battery. Therefore, in order to estimate the charging rate of a battery in the above-mentioned estimation device, a large number of data groups representing the relationship between the voltage and the charging rate for various charging / discharging currents and a large number of data groups representing the relationship between the voltage and the charging rate for various temperatures are required. In view of such circumstances, this specification provides a technology for estimating the charging rate of a battery with a simple configuration. [Means for solving the problem]

[0005] The technology disclosed in this specification is embodied in an estimation device that estimates a charging rate of a battery that supplies power to an auxiliary device mounted on a vehicle. The estimation device includes a voltage sensor that detects a voltage of the battery, a temperature sensor that detects a temperature of the battery, and a processing circuit that is connected to the voltage sensor and the temperature sensor and executes an estimation process to estimate the charging rate of the battery. The estimation process is executed while the vehicle is parked, and estimates the charging rate of the battery based on a detected voltage detected by the voltage sensor and a detected voltage detected by the temperature sensor.

[0006] In the above-mentioned estimation device, an estimation process is performed to estimate the charging rate of the battery while the vehicle is parked. In a battery that supplies power to the vehicle's auxiliary equipment, the discharge current (so-called dark current) when the vehicle is parked is sufficiently smaller than the discharge current when the vehicle is running, and the effect of such a discharge current on the battery voltage can be ignored. On the other hand, even when the vehicle is parked, the temperature of the battery changes in various ways due to the influence of the air temperature, etc., and the effect of such temperature changes on the battery voltage cannot be ignored. For this reason, in the above-mentioned estimation process, the charging rate of the battery is estimated based on the voltage and temperature of the battery. In this way, the timing for estimating the charging rate of the battery is limited to when the vehicle is parked, and the temperature of the battery is still taken into consideration, so that the charging rate of the battery can be accurately estimated with a simpler configuration than before. [Brief description of the drawings]

[0007] [Figure 1] 1 is a schematic diagram showing the configuration of a vehicle 100 and an estimation device 10. [Diagram 2] 5 is a flow diagram showing a series of processes executed by the processing circuit 18, in conjunction with FIG 2, where X in FIG 2 continues to X in FIG 5, and Y in FIG 5 continues to Y in FIG 2. [Diagram 3]3 is a diagram showing an example of the relationship between the charging rate and the voltage of the auxiliary battery 104. Note that graph (A) in Fig. 3 shows the case where the discharge current of the auxiliary battery 104 is a first current value A1, and graph (B) in Fig. 3 shows the case where the discharge current of the auxiliary battery 104 is a second current value A2. Here, the first current value A1 is smaller than the second current value A2. [Figure 4] 4 is a diagram showing an example of the relationship between the charging rate and the voltage of the auxiliary battery 104. Note that graph (C) in Fig. 4 shows the case where the temperature of the auxiliary battery 104 is a first temperature T1, and graph (D) in Fig. 4 shows the case where the temperature of the auxiliary battery 104 is a second temperature T2. Here, the first temperature T1 is higher than the second temperature T2. [Diagram 5] 5 is a flow diagram showing, together with FIG 2, a series of processes executed by processing circuit 18. Here, X in FIG 5 continues to X in FIG 2, and Y in FIG 5 continues to Y in FIG 2. [Figure 6] 1 is a graph showing an example of the change over time in the detected voltage of the voltage sensor 12 and the charging rate of the auxiliary battery 104 while the vehicle 100 is parked. In this example, the detected voltage and charging rate start at point E in the graph, and change through points F, G, H, I, J, and K to point L. The periods from point F to point G and from point I to point J indicate the periods during which the auxiliary battery 104 is being charged. The periods from point G to point H and from point J to point K indicate the periods immediately after charging of the auxiliary battery 104 is completed. [Figure 7] 7 is a flow chart showing, together with FIG 2, a modified example of a series of processes executed by the processing circuit 18. Here, X in FIG 7 continues to X in FIG 2, and Y in FIG 7 continues to Y in FIG 2. [Figure 8] FIG. 4 is a schematic diagram showing a modified example of the configuration of the vehicle 100. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] In one embodiment of the present technology, the estimation process may determine a relationship between the detected voltage and the charging rate according to the detected temperature, and estimate the charging rate using the determined relationship and the detected voltage. With this configuration, the charging rate of the battery can be accurately estimated based on both the detected voltage and the detected temperature of the battery. In this case, the processing circuit may previously store a relational expression, map, or table that describes the relationship between the detected voltage and the charging rate in association with various temperatures.

[0009] In one embodiment of the present technology, the processing circuit may stop the estimation process when charging of the battery is started while the vehicle is parked. Even when the vehicle is parked, the voltage detected by the voltage sensor depends on the charging voltage applied to the battery while the battery is being charged. For this reason, it is conceivable to stop the above-mentioned estimation process when charging of the battery is started while the vehicle is parked. This makes it possible to prevent the charging rate of the battery from being erroneously estimated while the battery is being charged.

[0010] In the above embodiment, the processing circuit may resume the estimation process when a predetermined condition is satisfied after the charging of the battery is completed. Even immediately after the charging of the battery is completed, the voltage output by the battery temporarily remains affected by the charging. During that time, the voltage detected by the voltage sensor does not necessarily correspond to the charging rate of the battery. For this reason, even after the charging of the battery is completed, it is possible to suspend the above-mentioned estimation process until a condition is satisfied that allows it to be determined that the influence of the charging has been substantially eliminated. This makes it possible to prevent the charging rate of the battery from being erroneously estimated immediately after the charging of the battery is completed.

[0011] In the above embodiment, the processing circuit may resume the estimation process when the amount of discharge from the battery after charging reaches the amount of charge charged to the battery during charging as a predetermined condition. That is, the estimation process may be resumed when the charging rate of the battery after charging reaches the charging rate of the battery at the start of charging. Immediately after the charging of the battery is completed, the influence of the charging remains temporarily inside the battery. During that time, the voltage detected by the voltage sensor does not necessarily correspond to the charging rate of the battery. For this reason, it is considered to stop the above-mentioned estimation process even after the charging of the battery is completed until the charging rate of the battery returns to the charging rate before charging. This makes it possible to prevent the charging rate of the battery from being erroneously estimated immediately after the charging of the battery is completed.

[0012] Instead of the above-described embodiment, the processing circuit may store the detected voltage and the detected temperature at the start of charging. In this case, the processing circuit may resume the estimation process when the charging rate estimated from the detected voltage and the detected temperature after the end of charging falls to the charging rate estimated from the detected voltage and the detected temperature at the start of charging, as the above-described predetermined condition. With this configuration, even if the temperature of the battery at the start of charging and the temperature of the battery at the end of charging are different from each other, it is possible to correctly identify the timing at which the charging rate of the battery after the end of charging becomes equal to the charging rate at the start of charging. As a result, the above-described estimation process can be stopped until the charging rate of the battery returns to the charging rate before charging, and it is possible to avoid erroneous estimation of the charging rate of the battery.

[0013] In some of the above-described embodiments, while the estimation process is stopped, the processing circuit may estimate the charging rate of the battery based on the charging rate at the start of charging, the charge amount charged to the battery during charging, and the discharge amount discharged from the battery after charging. That is, while the battery is being charged or in the period immediately thereafter, the charging rate of the battery may be estimated using a method different from the estimation process described above. With this configuration, the charging rate of the battery can be estimated even while the battery is being charged or in the period immediately thereafter.

[0014] Instead of the above embodiment, the processing circuit may estimate the battery charging rate while the estimation process is stopped based on the charging rate at the start of charging, the charge amount charged to the battery during charging, and the amount of discharge of the battery estimated from the elapsed time after charging. With this configuration, the battery charging rate can be estimated during charging and immediately after charging.

[0015] In some of the above-described embodiments, when charging the battery, the lower the detected temperature of the battery is, the more the charging current to the battery may be limited. With this configuration, the influence on the battery caused by the charging of the battery can be suppressed or substantially eliminated. As a result, the charging rate of the battery can be accurately estimated even after the battery is charged.

[0016] In some of the above-described embodiments, the battery may be charged by a solar charging system installed in the vehicle. In this configuration, the charging current of the battery when the vehicle is parked is sufficiently small that the effect of the charging current on the battery can be substantially ignored.

[0017] Alternatively or in addition to the above-described embodiment, the battery may be charged by an external power source connected to the vehicle. Even in this configuration, if the charging current supplied to the battery is sufficiently small, the effect of the charging current on the battery can be substantially negligible. EXAMPLES

[0018] An estimation device 10 according to an embodiment and a vehicle 100 employing the same will be described with reference to the drawings. The vehicle 100 referred to here is a so-called automobile, which is a vehicle that runs on a road surface. Here, the road surface is not limited to a so-called public road, but also includes private land and an indoor floor surface on which the vehicle 100 can run. The technology described in this embodiment is not limited to vehicles that run on a road surface, and can also be effectively adopted for vehicles that run on a track. Furthermore, the technology disclosed in this embodiment is not limited to the vehicle 100, but can be adopted for moving bodies such as ships and aircraft.

[0019] As shown in FIG. 1, the vehicle 100 includes a main battery 102, an auxiliary battery 104, and an auxiliary device 106. The main battery 102 is a battery that supplies power to a driving motor (not shown) of the vehicle 100 and the like. The auxiliary battery 104 is a battery that supplies power to an auxiliary device 106 mounted on the vehicle 100. The auxiliary device 106 is, for example, a room lamp, a car navigation device, and the like. The auxiliary battery 104 is electrically connected to the auxiliary device 106 and can supply power to the auxiliary device 106. The auxiliary device 106 can operate by the power supplied from the auxiliary battery 104. The rated voltage of the auxiliary battery 104 is lower than the rated voltage of the main battery 102. As an example, the rated voltage of the auxiliary battery 104 is 12V, and the rated voltage of the main battery 102 is 200V to 600V.

[0020] Each of the main battery 102 and the auxiliary battery 104 is a secondary battery in which multiple battery cells are connected in series. The specific number of multiple battery cells that each of the main battery 102 and the auxiliary battery 104 has is not particularly limited, and may be at least one. Each of the multiple battery cells is, for example, a lithium ion battery. However, each of the multiple battery cells does not necessarily have to be a lithium ion battery, and may be another battery such as a nickel-metal hydride battery.

[0021] As shown in FIG. 1, the vehicle 100 further includes a DC-DC converter 108 and a control device 110. The DC-DC converter 108 is a device that boosts or lowers the input DC power and outputs it. The control device 110 is a device that monitors and controls the operation of the vehicle 100. The DC-DC converter 108 is provided between the main battery 102 and the auxiliary battery 104, and can lower the DC power from the main battery 102 and supply it to the auxiliary battery 104 side (for example, the auxiliary battery 104 and the auxiliary device 106). The DC-DC converter 108 is configured to be able to communicate with the control device 110, and the operation of the DC-DC converter 108 is controlled by the control device 110. Therefore, the control device 110 can control the operation of the DC-DC converter 108 to charge the auxiliary battery 104 by the main battery 102.

[0022] Next, the estimation device 10 will be described. The estimation device 10 is a device that estimates the charging rate of the auxiliary battery 104. As shown in FIG. 1, the estimation device 10 includes a voltage sensor 12, a current sensor 14, a temperature sensor 16, and a processing circuit 18. The voltage sensor 12 is electrically connected to both ends of the auxiliary battery 104 and can detect the voltage of the auxiliary battery 104. The current sensor 14 is connected in series with the auxiliary battery 104 and can detect the current of the auxiliary battery 104. The temperature sensor 16 is disposed, for example, in a case in which the auxiliary battery 104 is accommodated and can detect the temperature of the auxiliary battery 104. The processing circuit 18 is communicatively connected to the sensors 12, 14, and 16 and can monitor the voltage, current, and temperature of the auxiliary battery 104 detected by the sensors 12, 14, and 16. Although details will be described later, the processing circuit 18 is configured to be able to execute a series of processes including an estimation process for estimating the charging rate of the auxiliary battery 104.

[0023] The processing circuit 18 is also connected to the control device 110 so as to be able to communicate with the control device 110, and can transmit information regarding the state of the auxiliary battery 104 to the control device 110, and can receive information regarding the state of the vehicle 100 from the control device 110. As an example, the processing circuit 18 can transmit the charging rate of the auxiliary battery 104 to the control device 110. In addition, although not limited to this, when the vehicle 100 is driven or parked by the user, the control device 110 can transmit a corresponding notification (e.g., a driving start notification or a parking start notification) to the processing circuit 18. Here, the vehicle 100 being parked refers to a state in which the vehicle 100 is continuously stopped, and includes, for example, a state in which the main switch of the vehicle 100 is turned off. Therefore, when the main switch of the vehicle 100 is turned off, the control device 110 transmits a parking start notification to the processing circuit 18, and when the main switch of the vehicle 100 is turned on, the control device 110 transmits a driving start notification to the processing circuit 18. Note that the main switch of the vehicle 100 may be called an ignition switch, following the custom for engine vehicles. The control device 110 can start and stop charging of the auxiliary battery 104 by the main battery 102 by controlling the operation of the DC-DC converter 108 based on the charging rate of the auxiliary battery 104 received from the processing circuit 18, the parking time of the vehicle 100, etc.

[0024] Next, a series of processes executed by the processing circuit 18 will be described with reference to Fig. 2 to Fig. 6. In step S10 of Fig. 2, the processing circuit 18 judges whether or not the vehicle 100 is parked. As described above, when the vehicle 100 is parked, the control device 110 transmits a parking start notification to the processing circuit 18 of the estimation device 10. When the processing circuit 18 receives the parking start notification (YES in step S10), the processing circuit 18 proceeds to processing in step S12. On the other hand, if NO in step S10, the processing circuit 18 ends the series of processes.

[0025] In step S12, the processing circuit 18 determines whether charging of the auxiliary battery 104 has started. When the vehicle 100 is parked, power is supplied from the auxiliary battery 104 to the auxiliary device 106, so that the charging rate of the auxiliary battery 104 decreases over time. However, as described above, the control device 110 is configured to charge the auxiliary battery 104 by the main battery 102 based on the charging rate of the auxiliary battery 104, the parking time of the vehicle 100, and the like. The processing circuit 18 can detect that charging of the auxiliary battery 104 has started based on the detection values ​​of the sensors 12, 14, and 16, and the like. In another embodiment, the control device 110 may be configured to notify the processing circuit 18 of the start and stop of charging of the auxiliary battery 104 by the main battery 102. In this case, the processing circuit 18 may determine whether charging of the auxiliary battery 104 has started based on the notification from the control device 110. If NO in step S12, the processing circuit 18 proceeds to step S 14. If YES in step S12, the processing circuit 18 proceeds to step S20 in FIG. 5 via X in FIG.

[0026] In step S14, the processing circuit 18 acquires the detected voltage detected by the voltage sensor 12 and the detected temperature detected by the temperature sensor 16. While the auxiliary battery 104 is discharging, the detected voltage by the voltage sensor 12 coincides with the voltage of the auxiliary battery 104. Also, the detected temperature by the temperature sensor 16 coincides with the temperature of the auxiliary battery 104.

[0027] In step S16, the processing circuit 18 executes an estimation process to estimate the charging rate of the auxiliary battery 104 based on the voltage and temperature of the auxiliary battery 104 acquired in step S14. It is generally known that the relationship between the voltage of the battery and the charging rate varies depending on the charging and discharging current of the battery and the temperature of the battery. However, as shown in FIG. 3, the discharge current (so-called dark current) of the auxiliary battery 104 when the vehicle 100 is parked is, for example, 300 mA or less, which is sufficiently smaller than the discharge current when the vehicle 100 is running. Therefore, in the relationship between the voltage of the auxiliary battery 104 and the charging rate, the influence of the discharge current can be ignored. Graph (A) in FIG. 3 shows the relationship between the voltage and the charging rate when the discharge current of the auxiliary battery 104 is a first current value A1, and graph (B) in FIG. 3 shows the relationship between the voltage and the charging rate when the discharge current of the auxiliary battery 104 is a second current value A2. Here, the first current value A1 is smaller than the second current value A2, for example, the first current value A1 is 30 mA, and the second current value A2 is 300 mA. In addition, the temperatures of the auxiliary battery 104 are equal in the graphs (A) and (B) in Fig. 3. From the above, in the process of step S16, the influence of the discharge current of the auxiliary battery 104 can be ignored.

[0028] On the other hand, as shown in FIG. 4, the relationship between the voltage and the charging rate of the auxiliary battery 104 changes depending on the temperature of the auxiliary battery 104. Graph (C) in FIG. 4 shows the relationship between the charging rate and the voltage of the auxiliary battery 104 at a first temperature T1, and graph (D) in FIG. 4 shows the relationship between the charging rate and the voltage of the auxiliary battery 104 at a second temperature T2. Here, the first temperature T1 is higher than the second temperature T2, for example, the first temperature T1 is 25 degrees, and the second temperature T2 is -25 degrees. In addition, the discharge currents of the auxiliary battery 104 are equal to each other in the graphs (C) and (D) in FIG. 4. For example, when the voltage of the auxiliary battery 104 is VD, if the temperature of the auxiliary battery 104 is the first temperature T1, the charging rate is a first charging rate S1, and if the temperature of the auxiliary battery 104 is the second temperature T2, the charging rate is a second charging rate S2. The first charging rate S1 is significantly lower than the second charging rate S2. As described above, the relationship between the voltage and the charging rate of the auxiliary battery 104 changes depending on the temperature of the auxiliary battery 104, so that the effect of the temperature of the auxiliary battery 104 needs to be taken into consideration in the process of step S16.

[0029] In consideration of the above, in step S16, the processing circuit 18 determines the relationship between the detected voltage and the charging rate according to the detected temperature, and estimates the charging rate of the auxiliary battery 104 using the determined relationship and the detected voltage. As an example, the processing circuit 18 can store in advance a relational expression describing the relationship between the detected voltage and the charging rate in association with various temperatures. The processing circuit 18 determines a relational expression describing the relationship between the charging rate and the voltage according to the detected temperature of the auxiliary battery 104, and estimates the charging rate from the detected voltage of the auxiliary battery 104 using the determined relational expression. When the processing of step S16 is completed, the processing circuit 18 ends the series of processes.

[0030] In another embodiment, the processing circuit 18 may store in advance a map or table describing the relationship between the detected voltage and the charging rate in association with various temperatures in addition to or instead of the above-mentioned relational expression. In this case, the processing circuit 18 may determine a map or table describing the relationship between the charging rate and voltage according to the detected temperature of the auxiliary battery 104, and estimate the charging rate using the map or table and the detected voltage of the auxiliary battery 104.

[0031] Next, referring to FIG. 5 and FIG. 6, a process will be described when step S12 in FIG. 2 is YES, that is, when charging of the auxiliary battery 104 is started while the vehicle 100 is parked. As described above, when step S12 in FIG. 2 is YES, the processing circuit 18 proceeds to step S20 in FIG. 5. As a result, the estimation process in steps S14 and S16 in FIG. 2 is stopped while the auxiliary battery 104 is being charged. As shown in FIG. 6, even when the vehicle 100 is parked, while the auxiliary battery 104 is being charged (from point F to point G or from point I to point J in the figure), the voltage detected by the voltage sensor 12 depends on the charging voltage applied to the auxiliary battery 104. That is, the voltage detected by the voltage sensor 12 does not necessarily correspond to the charging rate of the auxiliary battery 104. For this reason, when charging of the auxiliary battery 104 is started while the vehicle 100 is parked, the above-mentioned estimation process is stopped. This makes it possible to prevent the charging rate of the auxiliary battery 104 from being erroneously estimated while the auxiliary battery 104 is being charged.

[0032] In addition, the processing circuit 18 returns to the processing of step S14 in FIG. 2 when the charging of the auxiliary battery 104 is completed (NO in step S22) and a predetermined condition is satisfied (YES in step 32). As a result, the estimation processing in steps S14 and S16 in FIG. 2 is stopped not only during the charging of the auxiliary battery 104 but also immediately after the charging is completed. As shown in FIG. 6, even immediately after the charging of the auxiliary battery 104 is completed (from point G to point H or from point J to point K in the figure), the influence of the charging remains temporarily on the voltage output by the auxiliary battery 104. During that time, the voltage detected by the voltage sensor 12 does not necessarily correspond to the charging rate of the auxiliary battery 104. For this reason, even after the charging of the auxiliary battery 104 is completed, the above-mentioned estimation processing is stopped until a condition is satisfied that can be determined that the influence of the charging is substantially eliminated. As a result, it is possible to prevent the charging rate of the auxiliary battery 104 from being erroneously estimated immediately after the charging of the auxiliary battery 104 is completed.

[0033] As described above, the estimation processes in steps S14 and S16 in Fig. 2 are suspended while the auxiliary battery 104 is being charged and immediately after charging is completed. During this period, the processing circuit 18 executes the process shown in Fig. 5 to determine the timing to return to the process of step S14 in Fig. 2 and to simply estimate the charging rate of the auxiliary battery 104.

[0034] First, in step S20, the processing circuit 18 stores the detected voltage detected by the voltage sensor 12 and the detected temperature detected by the temperature sensor 16 at the start of charging. Then, the processing circuit 18 estimates the charging rate of the auxiliary battery 104, for example, by a method similar to the processing of step S16 in FIG.

[0035] In step S22, the processing circuit 18 determines whether or not the auxiliary battery 104 is being charged. If the auxiliary battery 104 is being charged (YES in step S22), the processing circuit 18 calculates the charge amount due to the charging in step S24. For example, the processing circuit 18 calculates the charge amount of the auxiliary battery 104 by integrating the current value of the auxiliary battery 104 acquired using the current sensor 14. If the auxiliary battery 104 is not being charged (NO in step S22), the processing circuit 18 omits the process of step S24.

[0036] In step S26, the processing circuit 18 determines whether or not the auxiliary battery 104 is discharging. If the auxiliary battery 104 is discharging (YES in step S26), the processing circuit 18 calculates the amount of discharge due to the discharge in step S28. In this case, as in step S24, the processing circuit 18 calculates the amount of discharge of the auxiliary battery 104, for example, by integrating the current detected by the current sensor 14. If the auxiliary battery 104 is not discharging (NO in step S26), the processing circuit 18 omits the process of step S28.

[0037] In step S30, the processing circuit 18 simply estimates the charging rate of the auxiliary battery 104. As an example, the processing circuit 18 estimates the charging rate of the auxiliary battery 104 based on the charging rate at the start of charging the auxiliary battery 104 (corresponding to points F and I in FIG. 6), the charge amount charged to the auxiliary battery 104 during charging, and the discharge amount discharged from the auxiliary battery 104 after charging. For example, the processing circuit 18 estimates the charging rate of the auxiliary battery 104 from the charging rate of the auxiliary battery 104 at the start of charging estimated in step S20 and the difference between the charge amount calculated in step S22 and the discharge amount calculated in step S26. Note that the start of charging the auxiliary battery 104 refers to the timing immediately before charging of the auxiliary battery 104 starts, and means the timing before a charging voltage is applied to the auxiliary battery 104.

[0038] Instead of the above embodiment, in step S30, the processing circuit 18 may estimate the charging rate of the auxiliary battery 104 based on the charging rate at the start of charging the auxiliary battery 104, the charge amount charged to the auxiliary battery 104 during charging, and the discharge amount of the auxiliary battery 104 estimated from the elapsed time after charging. In this case, for example, the processing circuit 18 may estimate the discharge amount discharged from the auxiliary battery 104 after charging from the elapsed time after charging of the auxiliary battery 104 by storing the discharge amount of the auxiliary battery 104 per day in advance. In this way, in step S30, the processing circuit 18 does not necessarily need to use the discharge amount calculated in step S28 as the discharge amount discharged from the auxiliary battery 104 after charging. The discharge amount of the auxiliary battery 104 per day may be empirically set based on the use conditions of the vehicle 100, or may be set according to the type of the auxiliary device 106 mounted on the vehicle 100.

[0039] In step S32, the processing circuit 18 judges whether the discharge amount discharged from the auxiliary battery 104 after charging reaches the charge amount charged to the auxiliary battery 104 during charging. In detail, the processing circuit 18 judges whether the discharge amount calculated in step S28 reaches the charge amount calculated in step S24. Until the discharge amount calculated in step S28 reaches the charge amount calculated in step S24 (NO in step S32), the processing circuit 18 returns to step S22. When the discharge amount calculated in step S28 reaches the charge amount calculated in step S24 (YES in step S32), the processing circuit 18 returns to the processing of step S14 in FIG. 2 via Y in FIG. 5. Here, in this embodiment, "the discharge amount discharged from the auxiliary battery 104 after charging reaches the charge amount charged to the auxiliary battery 104 during charging" is an example of a predetermined condition for resuming the estimation processing in the present technology.

[0040] In the above-described estimation device 10, an estimation process (steps S14 and S16 in FIG. 2) is executed to estimate the charging rate of the auxiliary battery 104 while the vehicle 100 is parked. In the auxiliary battery 104 of the vehicle 100, the discharge current when the vehicle 100 is parked is sufficiently smaller than the discharge current when the vehicle 100 is running, and the effect of such a discharge current on the voltage of the auxiliary battery 104 can be ignored (see FIG. 3). On the other hand, even when the vehicle 100 is parked, the temperature of the auxiliary battery 104 changes in various ways due to the influence of the air temperature and the like, and the effect of such a temperature change on the voltage of the auxiliary battery 104 cannot be ignored (see FIG. 4). For this reason, in the above-described estimation process, the charging rate of the auxiliary battery 104 is estimated based on the voltage and temperature of the auxiliary battery 104. In this way, by limiting the timing for estimating the charging rate of the auxiliary battery 104 to when the vehicle 100 is parked, while still taking into account the temperature of the auxiliary battery 104, the charging rate of the auxiliary battery 104 can be estimated with greater accuracy using a simpler configuration than in the past.

[0041] The series of processes executed by the processing circuit 18 can be appropriately changed. As an example, a modified example of the series of processes executed by the processing circuit 18 will be described. In this modified example, the processing circuit 18 of the estimation device 10 can execute the process shown in FIG. 7 instead of the process shown in FIG. 5. That is, in the case of YES in step S12 of the processing circuit 18, instead of moving to step S20 of FIG. 5 via X in FIG. 2, the processing circuit 18 can move to step S40 of FIG. 7. Then, in the case of YES in step S46 of FIG. 7, the processing circuit 18 can return to the process of step S14 of FIG. 2 via Y in FIG. 7. Note that, among the processes shown in FIG. 7, detailed descriptions of the processes similar to the above-mentioned processes will be omitted by showing the corresponding steps.

[0042] In step S40, the processing circuit 18 stores the detected voltage and the detected temperature at the start of charging, similar to step S20 in FIG. 5. At this time, the processing circuit 18 may estimate the charging rate of the auxiliary battery 104, although this is not limited thereto. In step S42, the processing circuit 18 acquires the detected voltage and the detected temperature, similar to step S14 in FIG. 2. In step S44, the processing circuit 18 simply estimates the charging rate of the auxiliary battery 104, similar to step S30 in FIG. 5. The process of step S42 is performed both during charging of the auxiliary battery 104 and during the period immediately after the charging is completed. Therefore, the charging rate estimated in step S44 includes both the charging rate of the auxiliary battery 104 during charging and the charging rate of the auxiliary battery 104 discharged after the charging is completed.

[0043] As described above, the relationship between the voltage and the charging rate of the auxiliary battery 104 changes depending on the temperature of the auxiliary battery 104. Therefore, when the temperature of the auxiliary battery 104 at the start of charging differs from the temperature of the auxiliary battery 104 after charging is completed, there is a risk that the timing at which the charging rate after charging is completed becomes equal to the charging rate at the start of charging cannot be correctly identified by simply comparing the detected voltages at each point in time.

[0044] Regarding the above point, in step S46, the processing circuit 18 judges whether the charging rate estimated from the detected voltage and detected temperature after the end of charging has decreased to the charging rate estimated from the detected voltage and detected temperature at the start of charging. For example, the processing circuit 18 estimates the charging rate from the detected voltage at the start of charging, and calculates an estimated value of the charging rate after the end of charging based on the detected temperature at the start of charging and the detected temperature after the end of charging. Then, when the detected voltage after the end of charging has decreased to the estimated value of the charging rate (or a voltage value corresponding thereto) (YES in step S46), the processing circuit 18 returns to the processing of step S14 in FIG. 2 via Y in FIG. 7. Here, in this modified example, "the charging rate estimated from the detected voltage and detected temperature after the end of charging has decreased to the charging rate estimated from the detected voltage and detected temperature at the start of charging" is an example of a predetermined condition for resuming the estimation processing in the present technology.

[0045] With this configuration, even if the temperature of the auxiliary battery 104 at the start of charging differs from the temperature of the auxiliary battery 104 after charging is completed, it is possible to correctly identify the timing at which the charging rate of the auxiliary battery 104 after charging is completed becomes equal to the charging rate at the start of charging. This makes it possible to suspend the above-described estimation process until the charging rate of the auxiliary battery 104 returns to the charging rate before charging, thereby preventing the charging rate of the auxiliary battery 104 from being erroneously estimated.

[0046] In another embodiment of the present technology, in charging the auxiliary battery 104, the lower the detected temperature of the auxiliary battery 104, the more the charging current to the auxiliary battery 104 can be limited. As an example, when the detected temperature at the start of charging stored in step S20 of FIG. 5 or step S40 of FIG. 7 falls below a predetermined temperature lower limit, the processing circuit 18 notifies the control device 110 of that fact (and the detected temperature). Based on the notification from the processing circuit 18, the control device 110 limits the charging current from the main battery 102 to the auxiliary battery 104 to a predetermined value or less. Note that the predetermined value here can be appropriately changed according to the temperature (i.e., the detected temperature) and the charging rate of the auxiliary battery 104 of the auxiliary battery 104. With this configuration, the influence of the charging of the auxiliary battery 104 on the auxiliary battery 104 can be suppressed or substantially eliminated. As a result, even after the auxiliary battery 104 is charged, the charging rate of the auxiliary battery 104 can be accurately estimated.

[0047] As shown in FIG. 8, the vehicle 100 of the embodiment may further include a solar charging system 112. The solar charging system 112 mainly includes a solar panel 112a and a DC-DC converter 112b. The solar panel 112a is a battery module that is an assembly of solar battery cells that generate power by receiving irradiation of sunlight. The DC-DC converter 112b is a device that boosts or lowers the input direct current power and outputs it. The solar panel 112a is electrically connected to the auxiliary battery 104 via the DC-DC converter 112b. The power generated by the solar panel 112a is lowered by the DC-DC converter 112b and then supplied to the auxiliary battery 104. The operation of the DC-DC converter 112b is controlled by, for example, the control device 110. The control device 110 can start or stop charging the auxiliary battery 104 by the solar charging system 112 by controlling the operation of the DC-DC converter 112b.

[0048] Even when the vehicle 100 is equipped with the solar charging system 112, the processing circuit 18 can correctly estimate the charging rate of the auxiliary battery 104 by executing a series of processes shown in Figs. 2 and 5 (or Figs. 2 and 7). That is, even when the auxiliary battery 104 is charged by the solar charging system 112 instead of the main battery 102, the processing circuit 18 may select YES in step S12 in Fig. 2 and stop the estimation process in steps S14 and S16. Then, when the charging of the auxiliary battery 104 by the solar charging system 112 is completed (NO in step S22 in Fig. 5) and a predetermined condition is satisfied (YES in step S32), the processing circuit 18 may return to the process in step S14 in Fig. 2. In this way, in the series of processes shown in Figs. 2 and 5, the auxiliary battery 104 is charged not only by the main battery 102 but also by the solar charging system 112 mounted on the vehicle 100. Even when charging using the solar charging system 112, the charging current of the auxiliary battery 104 when the vehicle 100 is parked is sufficiently small, so that the effect of this charging current on the auxiliary battery 104 can be substantially ignored.

[0049] As shown in FIG. 8, the vehicle 100 of the embodiment may further include a charging port 114. In this case, the vehicle 100 does not necessarily have to include the solar charging system 112, and may include only the charging port 114. The charging port 114 is a component for electrically connecting the external power source 116 to the auxiliary battery 104. The charging port 114 is disposed at an arbitrary position of the vehicle 100, electrically connected to the auxiliary battery 104, and configured to be detachable from the external power source 116. When the external power source 116 is electrically connected to the charging port 114, charging of the auxiliary battery 104 by the external power source 116 is started, and when the external power source 116 is removed from the charging port 114, charging of the auxiliary battery 104 by the external power source 116 is stopped. Note that, although not limited thereto, when the rated voltage of the external power source 116 and the rated voltage of the auxiliary battery 104 are different, a DC-DC converter may be further provided between the charging port 114 and the auxiliary battery 104. Furthermore, the external power supply 116 is not limited to a DC power supply, and may be an AC power supply. In this case, an AC-DC converter may be further provided between the charging port 114 and the auxiliary battery 104.

[0050] Even if the vehicle 100 has the charging port 114, the processing circuit 18 can correctly estimate the charging rate of the auxiliary battery 104 by executing a series of processes shown in Figures 2 and 5 (or Figures 2 and 7). That is, even if the auxiliary battery 104 is charged by the external power source 116, the processing circuit 18 may select YES in step S12 in Figure 2 and stop the estimation process in steps S14 and S16. Then, when the charging of the auxiliary battery 104 by the external power source 116 is completed (NO in step S22 in Figure 5) and a predetermined condition is satisfied (YES in step 32), the processing may return to the process of step S14 in Figure 2. Thus, in the series of processes shown in Figures 2 and 5, the auxiliary battery 104 is charged not only by the main battery 102 and the solar charging system 112 but also by the external power source 116. Even when charging from the external power supply 116, if the charging current of the auxiliary battery 104 is sufficiently small when the vehicle 100 is parked, the effect of the charging current on the auxiliary battery 104 can be substantially ignored.

[0051] The vehicle 100 in this embodiment is, for example, a hybrid vehicle, a fuel cell vehicle, an electric vehicle, a solar car, or the like. However, in another embodiment, the vehicle 100 may be an engine vehicle. In this case, the vehicle 100 may further include a generator such as an alternator that generates electricity using the power of the engine. The generator may be electrically connected to the auxiliary battery 104 and the auxiliary device 106, and may be configured to supply the electric power generated by the power of the engine to the auxiliary battery 104 and the auxiliary device 106.

[0052] Although several specific examples have been described in detail above, these are merely examples and do not limit the scope of the claims. The technology described in the claims includes various modifications and changes to the specific examples exemplified above. The technical elements described in this specification or drawings exhibit technical usefulness alone or in combination. [Explanation of symbols]

[0053] 10: Estimation device 12: Voltage sensor 14: Current sensor 16: Temperature sensor 18: Processing circuit 100: Vehicle 102: Main battery 104: Auxiliary battery 106: Auxiliary equipment 108: DC-DC converter 110: Control device 112: Solar charging system 112a: Solar panel 112b: DC-DC converter 114: Charging port 116: External power supply

Claims

1. An estimation device for estimating a charging rate of a battery that supplies power to an auxiliary device mounted on a vehicle, comprising: a voltage sensor for detecting a voltage of the battery; a temperature sensor for detecting a temperature of the battery; a current sensor for detecting a current of the battery; a processing circuit connected to the voltage sensor, the temperature sensor, and the current sensor, for performing an estimation process to estimate the charging rate of the battery; Equipped with The estimation process is executed while the vehicle is parked, and estimates the charging rate of the battery based on a detected voltage detected by the voltage sensor and a detected temperature detected by the temperature sensor; The processing circuitry includes: By integrating the detected current detected by the current sensor, it is possible to calculate the amount of charge charged to the battery and the amount of discharged from the battery, When charging of the battery is started while the vehicle is parked, the estimation process is stopped; After the charging of the battery is completed, the estimation process is resumed when the amount of discharge from the battery after the charging reaches the amount of charge charged to the battery during the charging. Estimation device.

2. An estimation device for estimating a charging rate of a battery that supplies power to an auxiliary device mounted on a vehicle, comprising: a voltage sensor for detecting a voltage of the battery; a temperature sensor for detecting a temperature of the battery; a processing circuit connected to the voltage sensor and the temperature sensor, the processing circuit executing an estimation process for estimating the charging rate of the battery; Equipped with The estimation process is executed while the vehicle is parked, and estimates the charging rate of the battery based on a detected voltage detected by the voltage sensor and a detected temperature detected by the temperature sensor; The processing circuitry includes: When charging of the battery is started while the vehicle is parked, the estimation process is stopped and the detected voltage and the detected temperature are stored at the start of the charging. after the charging of the battery is completed, when the charging rate estimated from the detected voltage and the detected temperature after the charging is completed drops to the charging rate estimated from the detected voltage and the detected temperature at the start of the charging, the estimation process is resumed; Estimation device.

3. An estimation device for estimating a charging rate of a battery that supplies power to an auxiliary device mounted on a vehicle, comprising: a voltage sensor for detecting a voltage of the battery; a temperature sensor for detecting a temperature of the battery; a current sensor for detecting a current of the battery; a processing circuit connected to the voltage sensor, the temperature sensor, and the current sensor, for performing an estimation process to estimate the charging rate of the battery; Equipped with The estimation process is executed while the vehicle is parked, and estimates the charging rate of the battery based on a detected voltage detected by the voltage sensor and a detected temperature detected by the temperature sensor; The processing circuitry includes: By integrating the detected current detected by the current sensor, it is possible to calculate the amount of charge charged to the battery and the amount of discharge of the battery, When charging of the battery is started while the vehicle is parked, the estimation process is stopped; While the estimation process is stopped, the charging rate of the battery is estimated based on the charging rate at the start of the charging, the amount of charge charged to the battery during the charging, and the amount of discharged from the battery after the charging; restarting the estimation process when a predetermined condition is satisfied that allows it to be determined that the influence of the charging has been substantially eliminated after the charging of the battery is completed; Estimation device.

4. An estimation device for estimating a charging rate of a battery that supplies power to an auxiliary device mounted on a vehicle, comprising: a voltage sensor for detecting a voltage of the battery; a temperature sensor for detecting a temperature of the battery; a current sensor for detecting a current of the battery; a processing circuit connected to the voltage sensor, the temperature sensor, and the current sensor, for performing an estimation process to estimate the charging rate of the battery; Equipped with The estimation process is executed while the vehicle is parked, and estimates the charging rate of the battery based on a detected voltage detected by the voltage sensor and a detected temperature detected by the temperature sensor; The processing circuitry includes: a current sensor connected to the battery, and capable of calculating a charge amount of the battery by integrating a current detected by the current sensor; a discharge amount of the battery per predetermined period is stored in advance, and the discharge amount discharged from the battery after the charging is completed can be estimated based on the elapsed time after the charging of the battery is completed; When charging of the battery is started while the vehicle is parked, the estimation process is stopped; While the estimation process is stopped, the charging rate of the battery is estimated based on the charging rate at the start of the charging, the charge amount charged to the battery during the charging, and the discharge amount of the battery estimated from the elapsed time after the charging; restarting the estimation process when a predetermined condition is satisfied that allows it to be determined that the influence of the charging has been substantially eliminated after the charging of the battery is completed; Estimation device.

5. The estimation device according to claim 1 , wherein the estimation process determines a relationship between the detected voltage and the charging rate in accordance with the detected temperature, and estimates the charging rate using the determined relationship and the detected voltage.

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