Battery temperature estimation method and apparatus

Abstract

To improve an estimation accuracy of a temperature of a battery arranged in an engine compartment with an engine.SOLUTION: A battery temperature estimation method of the present disclosure, includes steps of: estimating a temperature of a battery arranged into an engine compartment with an engine; estimating an atmospheric temperature of the battery from a suction temperature of the engine; estimating a housing temperature of the battery on the basis of the atmospheric temperature to be estimated and a first annealing coefficient; estimating a battery liquid temperature of the battery on the basis of the housing temperature to be estimated and a second annealing coefficient; and changing the first and second annealing coefficients in accordance with the suction temperature.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present disclosure relates to a battery temperature estimation method and apparatus for estimating the temperature of a battery disposed together with an engine in an engine compartment.

Background Art

[0002] Conventionally, a battery temperature estimation device for estimating the battery liquid temperature of a battery attached to an engine has been known (see, for example, Patent Document 1). This temperature estimation device calculates the amount of change in the battery liquid temperature based on the temperature of the outer periphery of the battery estimated based on the detected temperature of the intake air temperature sensor at a certain point while the engine is running, the battery liquid temperature calculated last time, and a model formula representing a heat conduction phenomenon with a heat conduction delay between the outer periphery of the battery and the battery liquid. Further, the temperature estimation device sequentially estimates the battery liquid temperature by calculating the battery liquid temperature at the above point from the battery liquid temperature calculated last time and the amount of change in the temperature.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] According to the above conventional temperature estimation device, even in a situation where the engine stop time is short and the temperature of the outer periphery of the battery and the battery liquid deviate without providing a temperature sensor in the battery liquid, the battery liquid temperature can be estimated. However, it is difficult to adapt the model formula in the temperature estimation device to all of the environments around the battery assumed, and the temperature estimation device still has room for improvement in improving the temperature estimation accuracy of the battery liquid.

[0005] Therefore, the primary objective of this disclosure is to further improve the accuracy of estimating the temperature of a battery located in the engine compartment together with the engine. [Means for solving the problem]

[0006] The battery temperature estimation method of this disclosure is a battery temperature estimation method for estimating the temperature of a battery disposed together with an engine in an engine compartment, wherein the ambient temperature of the battery is estimated from the intake air temperature of the engine, the housing temperature of the battery is estimated based on the estimated ambient temperature and a first annealing coefficient, the battery fluid temperature of the battery is estimated based on the estimated housing temperature and a second annealing coefficient, and the first and second annealing coefficients are changed according to the intake air temperature.

[0007] Furthermore, the battery temperature estimation device of this disclosure is a battery temperature estimation device for estimating the temperature of a battery disposed together with the engine in the engine compartment, and comprises: ambient temperature estimation means for estimating the ambient temperature of the battery from the intake air temperature of the engine; housing temperature estimation means for estimating the housing temperature of the battery based on the ambient temperature estimated by the ambient temperature estimation means and a first annealing coefficient; and battery fluid temperature estimation means for estimating the battery fluid temperature of the battery based on the housing temperature estimated by the housing temperature estimation means and a second annealing coefficient, wherein the first and second annealing coefficients are changed according to the intake air temperature.

[0008] The battery temperature estimation method and apparatus of this disclosure make it possible to further improve the accuracy of estimating the temperature of a battery located in the engine compartment together with the engine. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic diagram of a vehicle to which the battery temperature estimation method and apparatus of this disclosure are applied. [Figure 2] Figure 1 is a control block diagram of the vehicle. [Figure 3]This is a flowchart illustrating the battery temperature estimation method of this disclosure. [Figure 4] This is an explanatory diagram illustrating the estimation maps for high-temperature and low-temperature ambient temperatures. [Figure 5] This is an explanatory diagram illustrating the corrected enclosure temperature setting map and the corrected battery fluid temperature setting map. [Modes for carrying out the invention]

[0010] Next, with reference to the drawings, embodiments for carrying out the invention of this disclosure will be described.

[0011] Figure 1 is a schematic diagram of a vehicle 1 to which the battery temperature estimation method and apparatus of this disclosure are applied. The vehicle 1 shown in the figure includes an engine (internal combustion engine) 10 having a plurality of combustion chambers (cylinders) and a power transmission device 20 that transmits power from the engine 10 to the left and right drive wheels (rear wheels) DW. The vehicle 1 may be a rear-wheel drive vehicle, a front-wheel drive vehicle, or a four-wheel drive vehicle, as shown in the figure.

[0012] Engine 10 is a gasoline engine that burns a mixture of gasoline (hydrocarbon fuel) and air in multiple combustion chambers, converting the reciprocating motion of the pistons associated with the combustion of the mixture into rotational motion of a crankshaft (not shown). However, engine 10 may also be a diesel engine or an LPG engine. Furthermore, engine 10 includes a starter 11 that outputs cranking torque to the crankshaft to start the engine 10, and an alternator 12 that is driven by engine 10 to generate electricity.

[0013] Furthermore, an auxiliary battery 30 is located in the engine compartment 2 of the vehicle 1 where the engine 10 is situated. The auxiliary battery 30 is, for example, a lead-acid battery with a rated output voltage of approximately 12V, and includes a housing 31, battery fluid 35 stored inside the housing, a separator and electrodes (not shown), etc. The auxiliary battery 30 is charged by power from the alternator 12 and supplies power to various auxiliary components of the engine 10, including the starter 11, and on-board electrical equipment.

[0014] The power transmission system 20 includes a starting device 21, a mechanical oil pump 22 driven by power from the engine 10, a transmission 23, a differential gear (differential mechanism) 24, and a hydraulic control device 25. In this embodiment, the starting device 21 is a torque converter having a torque amplification effect and includes a lock-up clutch 21c and a damper mechanism 21d. The transmission 23 is a multi-speed (staged) transmission, for example, a 6-speed to 10-speed type, including an input shaft, an output shaft, a plurality of planetary gears, each with a plurality of clutches and brakes. However, the transmission 23 may be a continuously variable transmission (CVT) or a dual-clutch transmission. The transmission 23 transmits power from the engine 10 to the input shaft via the starting device 21 (torque converter or lock-up clutch 21c), changes the power in multiple stages, and outputs it from the output shaft to the left and right drive wheels DW via the differential gear 24 and drive shaft DS. Furthermore, the hydraulic control device 25 includes a valve body with multiple oil passages, multiple regulator valves, multiple linear solenoid valves, and the like.

[0015] Figure 2 is a control block diagram of vehicle 1. As shown in the figure, vehicle 1 includes an engine electronic control unit (hereinafter referred to as "EGECU") 100, a transmission electronic control unit (hereinafter referred to as "TMECU") 200, a brake electronic control unit (hereinafter referred to as "Brake ECU") 400, and a start-stop electronic control unit (hereinafter referred to as "S&SECU") 500. These ECUs 100, 200, 400, and 500 exchange information with each other via a shared communication line (CAN bus) CB.

[0016] EGECU100 includes a microcomputer (not shown) with a CPU, ROM, RAM, input / output interface, etc., and performs intake air volume control, fuel injection control, ignition timing control, etc. for the engine 10. In addition, when starting the engine 10, EGECU100 controls the starter 11 and also performs intake air volume control, fuel injection control, ignition timing control, etc. TMECU200 includes a microcomputer (not shown) with a CPU, ROM, RAM, input / output interface, etc., and controls the hydraulic control device 25 to adjust the hydraulic pressure from the mechanical oil pump 22 and supply it to the starting device 21, the clutch and brakes of the transmission 23, etc. Furthermore, brake ECU400 includes a microcomputer (not shown) with a CPU, ROM, RAM, input / output interface, etc., and controls the brake actuator 40 of the electronically controlled hydraulic brake system according to the amount the brake pedal is pressed. In addition, brake ECU400 controls the brake actuator 40, etc., so that braking force is applied to each wheel, including the drive wheels DW, regardless of the driver's pressure on the brake pedal, in response to requests from other ECUs, etc.

[0017] The S&SECU500 includes a microcomputer (not shown) with a CPU, ROM, RAM, input / output interface, etc., and performs idle stop control, stopping the engine 10 when predetermined stop conditions are met and starting the engine 10 when predetermined start conditions are met. Specifically, based on signals from the accelerator pedal position sensor 51 and the brake switch 52, the S&SECU500 instructs the EGECU100 to stop the operation of the engine 10 when the vehicle 1 is decelerating or stopped, and restarts the engine 10 in response to a driver's request to start the vehicle 1, such as releasing the brake pedal.

[0018] Here, when the temperature of the battery fluid 35 of the auxiliary battery 30 is high (for example, 65°C or higher) or extremely low (for example, -10°C or lower), it is preferable to prohibit the idling stop control (starting of the engine 10) from the viewpoints of suppressing deterioration due to discharge and ensuring the charge amount. For this reason, the S&SECU 500 acquires the signal from the intake air temperature sensor 15 of the engine 10, and based on the intake air temperature Ti detected by the intake air temperature sensor 15, estimates the temperature of the battery fluid 35 of the auxiliary battery 30 (hereinafter referred to as "battery fluid temperature") Tb disposed together with the engine 10 in the engine compartment 2. Then, the S&SECU 500 determines whether or not to execute the idling stop control based on the estimated battery fluid temperature Tb.

[0019] Subsequently, referring to FIGS. 3 to 5, the estimation procedure of the battery fluid temperature Tb by the S&SECU 500 as the battery temperature estimation device of the present disclosure, that is, the battery temperature estimation method of the present disclosure will be described.

[0020] FIG. 3 is a flowchart showing a battery temperature estimation routine repeatedly executed at predetermined intervals by the S&SECU 500 from when the start switch of the vehicle 1 is turned on and the engine 10 is started until the operation of the engine 10 is stopped. When the execution timing of the battery temperature estimation routine arrives, the S&SECU 500 acquires the intake air temperature Ti from the intake air temperature sensor 15 (step S100). Next, the S&SECU 500 estimates the high-temperature-side ambient temperature Tah and the low-temperature-side ambient temperature Tal based on the intake air temperature Ti acquired in step S100 (step S110). The high-temperature-side ambient temperature Tah is the temperature around the auxiliary battery 30 in the engine compartment 2 when the intake air temperature Ti is relatively high, that is, when the intake air temperature Ti is equal to or higher than a predetermined temperature Tref (for example, a temperature of about 10 - 20°C). The low-temperature-side ambient temperature Tal is the temperature around the auxiliary battery 30 in the engine compartment 2 when the intake air temperature Ti is relatively low, that is, when the intake air temperature Ti is lower than the predetermined temperature Tref.

[0021] In step S110, the S&SECU 500 derives the high-temperature-side ambient temperature Tah corresponding to the intake air temperature Ti obtained in step S100 from a pre-created high-temperature-side ambient temperature estimation map. Also, in step S110, the S&SECU 500 derives the low-temperature-side ambient temperature Tal corresponding to the intake air temperature Ti obtained in step S100 from a pre-created low-temperature-side ambient temperature estimation map. The high-temperature-side ambient temperature estimation map is created in advance through experiments and analyses based on the positions of the engine 10 and the auxiliary battery 30 in the engine compartment 2, etc., so as to define the correlation between the intake air temperature Ti and the high-temperature-side ambient temperature Tah when the intake air temperature Ti is higher than a predetermined temperature Tref and relatively high, and is stored in the ROM of the S&SECU 500. The low-temperature-side ambient temperature estimation map is created in advance through experiments and analyses based on the positions of the engine 10 and the auxiliary battery 30 in the engine compartment 2, etc., so as to define the correlation between the intake air temperature Ti and the low-temperature-side ambient temperature Tal when the intake air temperature Ti is lower than a predetermined temperature Tref and relatively low, and is stored in the ROM of the S&SECU 500.

[0022] In the present embodiment, the high-temperature-side ambient temperature estimation map is adapted so as to more appropriately determine whether to execute the idling stop control when the intake air temperature Ti is relatively high. That is, as shown by the solid line in FIG. 4, the high-temperature-side ambient temperature estimation map makes the high-temperature-side ambient temperature Tah substantially coincide with the intake air temperature Ti when the intake air temperature Ti is relatively low (for example, 40 - 50°C or less), and is created such that the high-temperature-side ambient temperature Tah becomes slightly lower than the intake air temperature Ti as the intake air temperature Ti increases. Also, the low-temperature-side ambient temperature estimation map is adapted so as to more appropriately determine whether to execute the idling stop control when the intake air temperature Ti is relatively low. That is, as shown by the broken line in FIG. 4, the low-temperature-side ambient temperature estimation map is created such that the low-temperature-side ambient temperature Tal is lower than the high-temperature-side ambient temperature Tah corresponding to the same intake air temperature Ti.

[0023] After estimating the high-temperature side ambient temperature Tah and the low-temperature side ambient temperature Tal, S&SECU500 determines whether or not the engine 10 has just been started (immediately after the start process has been completed) (step S120). If the engine 10 has just been started (step S120: YES), S&SECU500 derives the corrected housing temperature ΔTc and the corrected battery fluid temperature ΔTb based on the soak time from the previous stop of the engine 10 (system stop) to the current start (system start) (step S130). In step S130, S&SECU500 obtains the soak time and derives the corrected housing temperature ΔTc corresponding to the soak time from a pre-created corrected housing temperature setting map, and derives the corrected battery fluid temperature ΔTb corresponding to the soak time from a pre-created corrected battery fluid temperature setting map.

[0024] The corrected enclosure temperature setting map is pre-created through experiments and analyses to define the correlation between soak time and corrected enclosure temperature ΔTc, and is stored in the ROM of the S&SECU500. In this embodiment, as shown by the dashed line in Figure 5, the corrected enclosure temperature setting map is designed to gradually decrease the corrected enclosure temperature ΔTc from zero (increase its absolute value) as the soak time increases, and to converge the corrected enclosure temperature ΔTc to a constant value (negative value) when the soak time exceeds a predetermined time (e.g., 300 minutes). Similarly, the corrected battery fluid temperature setting map is pre-created through experiments and analyses to define the correlation between soak time and corrected battery fluid temperature ΔTb, and is stored in the ROM of the S&SECU500. As shown by the solid line in Figure 5, the corrected battery fluid temperature setting map is designed to gradually increase the corrected battery fluid temperature ΔTb from zero as the soak time increases, and to converge the corrected battery fluid temperature ΔTb to a constant value (positive value) when the soak time exceeds a predetermined time (e.g., 180 minutes).

[0025] In step S140, the S&SECU500 obtains the estimated housing temperature (temperature of housing 31) Tc and battery fluid temperature Tb of the auxiliary battery 30 at the time of the previous engine shutdown (step S140). Furthermore, the S&SECU500 sets the initial housing temperature Tc0, which is the smaller of the sum of the estimated housing temperature Tc at the time of the previous engine shutdown and the corrected housing temperature ΔTc derived in step S130, and the intake air temperature Ti obtained in step S100, as the initial value of the housing temperature Tc after the current engine 10 startup (step S140). In step S150, the S&SECU500 sets the initial battery fluid temperature Tb0, which is the smaller of the sum of the estimated battery fluid temperature Tb at the time of the previous engine shutdown and the corrected battery fluid temperature ΔTb derived in step S130, and the intake air temperature Ti obtained in step S100, as the initial value of the battery fluid temperature Tb after the current engine 10 startup. These steps S130-S150 are performed only once immediately after the engine 10 is started (immediately after the start process is completed), and thereafter are skipped until the engine 10 is stopped (step S120: NO).

[0026] After processing in step S120 or S150, S&SECU500 estimates (calculates) the high-temperature side housing temperature Tch (current value), which is the housing temperature of the auxiliary battery 30 when the intake air temperature Ti is equal to or greater than a predetermined temperature Tref, according to the following equation (1) based on the high-temperature side ambient temperature Tah estimated in step S110 (step S160). Also in step S160, S&SECU500 estimates (calculates) the low-temperature side housing temperature Tcl (current value), which is the housing temperature of the auxiliary battery 30 when the intake air temperature Ti is less than a predetermined temperature Tref, according to the following equation (2), based on the low-temperature side ambient temperature Tal estimated in step S110.

[0027] In Equation (1), "Previous Tch" is the high-side housing temperature Tch (previous value) estimated at the previous execution of the battery temperature estimation routine, and immediately after the start of the engine 10, it is the initial housing temperature Tc0 derived in Step S150. Also, in Equation (1), "n1h" is a tempering coefficient (first tempering coefficient, positive value) determined through experiments and analysis considering physical property values of air and the housing 31, etc. Further, in Equation (2), "Previous Tcl" is the low-side housing temperature Tcl (previous value) estimated at the previous execution of the battery temperature estimation routine, and immediately after the start of the engine 10, it is the initial housing temperature Tc0 derived in Step S150. Also, in Equation (2), "n1l" is a tempering coefficient (first tempering coefficient, positive value) determined through experiments and analysis considering physical property values of air and the housing 31, etc., and n1l < n1h. Thus, the high-side housing temperature Tch is estimated to change more significantly than the low-side housing temperature Tcl in response to changes in the intake air temperature Ti (ambient temperature).

[0028] Tch = Previous Tch + (Tah - Previous Tch) × n1h …(1) Tcl = Previous Tcl + (Tal - Previous Tcl) × n1l …(2)

[0029] Subsequently, based on the high-side housing temperature Tch estimated in Step S160, the S&SECU 500 estimates (calculates) the high-side battery liquid temperature Tbh (current value), which is the battery liquid temperature of the auxiliary battery 30 when the intake air temperature Ti is equal to or higher than the predetermined temperature Tref, according to the following Equation (3) (Step S170). Also, in Step S170, based on the low-side housing temperature Tcl estimated in Step S160, the S&SECU 500 estimates (calculates) the low-side battery liquid temperature Tbl (current value), which is the battery liquid temperature of the auxiliary battery 30 when the intake air temperature Ti is lower than the predetermined temperature Tref, according to the following Equation (4).

[0030] In Equation (3), "Previous Tbh" is the high-temperature-side battery liquid temperature Tbh (previous value) estimated at the previous execution of the battery temperature estimation routine, and immediately after the engine 10 starts, it is the initial battery liquid temperature Tb0 derived in step S150. Also, in Equation (3), "n2h" is a soaking coefficient (second soaking coefficient, positive value) determined through experiments and analyses considering physical property values of the housing 31 and the battery liquid 35, etc. Further, in Equation (4), "Previous Tbl" is the low-temperature-side battery liquid temperature Tbl (previous value) estimated at the previous execution of the battery temperature estimation routine, and immediately after the engine 10 starts, it is the initial battery liquid temperature Tb0 derived in step S150. Also, in Equation (4), "n2l" is a soaking coefficient (second soaking coefficient, positive value) determined through experiments and analyses considering physical property values of the housing 31 and the battery liquid 35, etc., and n2l < n2h. Thereby, the high-temperature-side battery liquid temperature Tbh is estimated to change more greatly than the low-temperature-side battery liquid temperature Tbl in response to changes in the intake air temperature Ti (ambient temperature).

[0031] Tbh = Previous Tbh + (Tch - Previous Tbh) × n2h …(3) Tbl = Previous Tbl + (Tcl - Previous Tbl) × n2l …(4)

[0032] Furthermore, S&SECU500 determines whether the intake air temperature Ti obtained in step S100 is equal to or greater than the predetermined temperature Tref (step S180). If the intake air temperature Ti is equal to or greater than the predetermined temperature Tref (step S180: YES), S&SECU500 sets the high-temperature side housing temperature Tch estimated in step S160 as the current housing temperature Tc of the auxiliary battery 30, and sets the high-temperature side battery fluid temperature Tbh estimated in step S170 as the current battery fluid temperature Tb of the auxiliary battery 30 (step S190), and terminates the battery temperature estimation routine. Furthermore, if the intake air temperature Ti is less than the predetermined temperature Tref (step S180: NO), S&SECU500 sets the low-temperature side housing temperature Tcl estimated in step S160 as the current housing temperature Tc of the auxiliary battery 30, and sets the low-temperature side battery fluid temperature Tbl estimated in step S170 as the current battery fluid temperature Tb of the auxiliary battery 30 (step S200), and then terminates the battery temperature estimation routine.

[0033] As described above, the S&SECU500, as a battery temperature estimation device, estimates the high-temperature ambient temperature Tah and the low-temperature ambient temperature Tal as the ambient temperatures of the auxiliary battery 30 from the intake air temperature Ti of the engine 10 (step S100). Furthermore, the S&SECU500 estimates the high-temperature side housing temperature Tch of the auxiliary battery 30 based on the estimated high-temperature side ambient temperature Tah and the annealing coefficient (first annealing coefficient) n1h, and estimates the low-temperature side housing temperature Tcl of the auxiliary battery 30 based on the estimated low-temperature side ambient temperature Tal and the annealing coefficient (first annealing coefficient) n1l (step S160). Furthermore, S&SECU500 estimates the high-temperature side battery fluid temperature Tbh of the auxiliary battery 30 based on the estimated high-temperature side housing temperature Tch and the annealing coefficient (second annealing coefficient) n2h, and estimates the low-temperature side battery fluid temperature Tbl of the auxiliary battery 30 based on the estimated low-temperature side housing temperature Tcl and the annealing coefficient (second annealing coefficient) n2l (step S170).

[0034] Then, if the intake air temperature Ti is above a predetermined temperature Tref (step S180: YES), S&SECU500 sets the estimated high-temperature side housing temperature Tch as the current housing temperature Tc of the auxiliary battery 30, and the estimated high-temperature side battery fluid temperature Tbh as the current battery fluid temperature Tb of the auxiliary battery 30 (step S190). Also, if the intake air temperature Ti is below a predetermined temperature Tref (step S180: NO), S&SECU500 sets the estimated low-temperature side housing temperature Tcl as the current housing temperature Tc of the auxiliary battery 30, and the estimated low-temperature side battery fluid temperature Tbl as the current battery fluid temperature Tb of the auxiliary battery 30 (step S200). In other words, when estimating the battery fluid temperature Tb as the temperature of the auxiliary battery 30, the S&SECU500 changes a first annealing coefficient for estimating the housing temperature Tc of the auxiliary battery 30 between annealing coefficients n1h and n1l, according to the intake air temperature Ti of the engine 10, and also changes a second annealing coefficient for estimating the battery fluid temperature Tb of the auxiliary battery 30 between annealing coefficients n2h and n2l.

[0035] As a result, even if the intake air temperature Ti, i.e., the actual ambient temperature of the auxiliary battery 30, changes, the high-temperature side housing temperature Tch and the low-temperature side housing temperature Tcl of the auxiliary battery 30 can be accurately estimated, and the battery fluid temperature Tb (high-temperature side battery fluid temperature Tbh or low-temperature side battery fluid temperature Tbl) can be accurately estimated from the estimated high-temperature side housing temperature Tch or low-temperature side housing temperature Tcl. As a result, in vehicle 1, it becomes possible to further improve the accuracy of estimating the battery fluid temperature Tb of the auxiliary battery 30, which is located in the engine compartment 2 together with the engine 10.

[0036] Furthermore, S&SECU500 estimates the high-temperature side ambient temperature Tah when the intake air temperature Ti is above a predetermined temperature Tref, and estimates the low-temperature side ambient temperature Tal to be lower than the high-temperature side ambient temperature Tah corresponding to the same intake air temperature Ti when the intake air temperature Ti is below the predetermined temperature Tref (step S110). In addition, S&SECU500 makes the annealing coefficient n1h for estimating the high-temperature side housing temperature Tch larger than the annealing coefficient n1l for estimating the low-temperature side housing temperature Tcl. Also, S&SECU500 makes the annealing coefficient n2h for estimating the high-temperature side battery fluid temperature Tbh larger than the annealing coefficient n2l for estimating the low-temperature side battery fluid temperature Tbl. This makes it possible to accurately estimate the high-temperature side housing temperature Tch or the low-temperature side housing temperature Tcl of the auxiliary battery 30 in both cases, when the intake air temperature Ti is high and when the intake air temperature Ti is low, and to accurately estimate the battery fluid temperature Tb (high-temperature side battery fluid temperature Tbh or low-temperature side battery fluid temperature Tbl) from the estimated high-temperature side housing temperature Tch or low-temperature side housing temperature Tcl.

[0037] Furthermore, when S&SECU500 estimates the battery fluid temperature Tb immediately after starting the engine 10 (step S120: YES), it sets the initial housing temperature (initial value) Tc0 as the lower of the sum of the housing temperature Tc at the time of the previous engine stop and the corrected housing temperature ΔTc according to the soak time, and the intake air temperature Ti. It also sets the initial battery fluid temperature (initial value) Tb0 as the lower of the sum of the battery fluid temperature Tb at the time of the previous engine stop and the corrected battery fluid temperature ΔTb according to the soak time, and the intake air temperature Ti (steps S130-S150). This makes it possible to appropriately set the initial values ​​of the housing temperature Tc and the battery fluid temperature Tb when estimating the battery fluid temperature Tb immediately after starting the engine.

[0038] Furthermore, steps S160-S200 in Figure 3 may be modified to estimate the battery fluid temperature Tb (high-temperature side battery fluid temperature Tbh) using the high-temperature side ambient temperature Tah, annealing coefficients n1h and n2h when the intake air temperature Ti is above a predetermined temperature Tref, and to estimate the battery fluid temperature Tb (low-temperature side battery fluid temperature Tbl) using the low-temperature side ambient temperature Tal, annealing coefficients n1l and n2l when the intake air temperature Ti is below the predetermined temperature Tref. In addition, in the above embodiment, the assumed range of intake air temperature Ti is divided into two by the predetermined temperature Tref, and the ambient temperatures Tah, Tal, housing temperatures Tch, Tcl, and battery fluid temperatures Tbh, Tbl are estimated for the high-temperature side and the low-temperature side. However, the assumed range of intake air temperature Ti may be divided into three or more, and the ambient temperature, housing temperature, and battery fluid temperature may be estimated for each temperature range.

[0039] As described above, the battery temperature estimation method of the present disclosure is a battery temperature estimation method for estimating the temperature of a battery (30) arranged together with an engine (10) in an engine compartment (2), wherein the ambient temperature (Tah, Tal) of the battery (30) is estimated from the intake air temperature (Ti) of the engine (10) (step S110), the housing temperature (Tch, Tcl) of the battery (30) is estimated based on the estimated ambient temperature (Tah, Tal) and a first annealing coefficient (n1h, n1l) (step S160), the battery fluid temperature (Tbh, Tbl, Tb) of the battery (30) is estimated based on the estimated housing temperature (Tch, Tcl, Tc) and a second annealing coefficient (n2h, n2l) (steps S170-S200), and the first and second annealing coefficients (n1h, n1l, n2h, n2l) are changed according to the intake air temperature (Ti).

[0040] In the battery temperature estimation method of this disclosure, a first annealing coefficient for estimating the battery housing temperature from the ambient temperature of the battery and a second annealing coefficient for estimating the battery fluid temperature from the housing temperature are changed according to the engine intake air temperature. As a result, even if the intake air temperature, i.e., the ambient temperature of the battery, changes, the battery housing temperature can be accurately estimated, and the battery fluid temperature can be accurately estimated from the estimated housing temperature. As a result, it becomes possible to further improve the accuracy of estimating the temperature of the battery, which is located in the engine compartment together with the engine.

[0041] Furthermore, when the intake air temperature (Ti) is above a predetermined temperature (Tref), the first and second annealing coefficients (n1h, n1l, n2h, n2l) may be increased compared to when the intake air temperature (Ti) is below the predetermined temperature (Tref).

[0042] This makes it possible to accurately estimate the battery housing temperature under both high and low intake air temperatures, and then accurately estimate the battery fluid temperature from the estimated housing temperature.

[0043] Furthermore, when the intake air temperature (Ti) is below a predetermined temperature (Tref), the ambient temperature (Tal) corresponding to the same intake air temperature (Ti) may be estimated to be lower than when the intake air temperature (Ti) is above the predetermined temperature (Tref).

[0044] Alternatively, the current value of the housing temperature (Tch, Tcl) may be calculated from the ambient temperature (Tah, Tal), the first annealing coefficient (n1h, n1l), and the previous value of the housing temperature (Tch, Tcl) (step S160), or the current value of the battery fluid temperature (Tbh, Tbl) may be calculated from the housing temperature (Tch, Tcl), the second annealing coefficient (n2h, n2l), and the previous value of the battery fluid temperature (Tbh, Tbl) (step S170), immediately after starting the engine (10) When estimating the battery fluid temperature (Tb), the lower of the sum of the housing temperature (Tc) at the time of the previous engine shutdown and the corrected housing temperature (ΔTc) according to the soak time, and the intake air temperature (Ti), may be used as the initial value (Tc0) of the housing temperature (Tc). Alternatively, the lower of the sum of the battery fluid temperature (Tb) at the time of the previous engine shutdown and the corrected battery fluid temperature (ΔTb) according to the soak time, and the intake air temperature (Ti), may be used as the initial value (Tb0) of the battery fluid temperature (tb).

[0045] This makes it possible to appropriately set the initial values ​​for the housing temperature and battery fluid temperature when estimating the battery fluid temperature immediately after engine startup.

[0046] The battery temperature estimation device of this disclosure is a battery temperature estimation device (500) for estimating the temperature of a battery (30) located in an engine compartment (2) together with an engine (10), and includes an ambient temperature estimation means (step S110) for estimating the ambient temperature (Tah, Tal) of the battery (30) from the intake air temperature (Ti) of the engine (10), and a first annealing coefficient (n1h, n1l) for estimating the temperature of the battery (30) based on the ambient temperature (Tah, Tal) estimated by the ambient temperature estimation means (step S110) and the battery (3 The system includes a housing temperature estimation means (step S160) for estimating the housing temperature (Tch, Tcl) of 0), and a battery fluid temperature estimation means (steps S170-S200) for estimating the battery fluid temperature (Tbh, Tbl, Tb) of the battery (30) based on the housing temperature (Tch, Tcl, Tc) estimated by the housing temperature estimation means (step S160) and a second annealing coefficient (n2h, n2l), wherein the first and second annealing coefficients (n1h, n1l, n2h, n2l) are changed according to the intake air temperature (Ti).

[0047] The battery temperature estimation device of this disclosure makes it possible to further improve the accuracy of estimating the temperature of a battery located in the engine compartment together with the engine.

[0048] Furthermore, the invention disclosed herein is not limited in any way to the embodiments described above, and it goes without saying that various modifications can be made within the scope of this disclosure. Moreover, the embodiments described above are merely one specific form of the invention described in the summary of the invention, and do not limit the elements of the invention described in the summary of the invention. [Industrial applicability]

[0049] The invention disclosed herein can be used in the vehicle manufacturing industry and the like. [Explanation of symbols]

[0050] 1 Vehicle, 2 Engine compartment, 10 Engine, 15 Intake air temperature sensor, 30 Auxiliary battery, 31 Housing, 35 Battery fluid.

Claims

1. In a battery temperature estimation method for estimating the temperature of a battery located in the engine compartment together with the engine, The ambient temperature of the battery is estimated from the intake air temperature of the engine. Based on the estimated ambient temperature and the first annealing coefficient, the temperature of the battery housing is estimated. Based on the estimated housing temperature and the second annealing coefficient, the battery fluid temperature of the battery is estimated. The first and second annealing coefficients are changed according to the intake air temperature. Battery temperature estimation method.

2. In the battery temperature estimation method described in claim 1, When the intake air temperature is above a predetermined temperature, the first and second annealing coefficients are increased compared to when the intake air temperature is below the predetermined temperature. Battery temperature estimation method.

3. In the battery temperature estimation method described in claim 2, A battery temperature estimation method that estimates the ambient temperature corresponding to the same intake air temperature lower when the intake air temperature is below the predetermined temperature compared to when the intake air temperature is above the predetermined temperature.

4. In the battery temperature estimation method according to any one of claims 1 to 3, The current value of the housing temperature is calculated from the ambient temperature, the first annealing coefficient, and the previous value of the housing temperature. The current value of the battery fluid temperature is calculated from the housing temperature, the second annealing coefficient, and the previous value of the battery fluid temperature. When estimating the battery fluid temperature immediately after starting the engine, the lower of the sum of the housing temperature at the time of the previous engine shutdown and the corrected housing temperature according to the soak time, and the intake air temperature, is used as the initial value of the housing temperature. Battery temperature estimation method.

5. In a battery temperature estimation device that estimates the temperature of a battery located in the engine compartment together with the engine, An ambient temperature estimation means for estimating the ambient temperature of the battery from the intake air temperature of the engine, A housing temperature estimation means for estimating the housing temperature of the battery based on the ambient temperature estimated by the ambient temperature estimation means and a first annealing coefficient, The system includes a battery fluid temperature estimation means that estimates the battery fluid temperature of the battery based on the housing temperature estimated by the housing temperature estimation means and a second annealing coefficient, A battery temperature estimation device that changes the first and second annealing coefficients according to the intake air temperature.

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