JP2018148720A - Battery control device and program - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery control device which improves estimation accuracy of a deterioration degree.SOLUTION: A battery control device 30 includes: a deterioration degree calculation part 2; a measurement part 3; an estimated deterioration degree calculation part 4; a point integration part 5; and a deterioration degree correction part 7. The deterioration calculation part 2 calculates a deterioration degree SOH of an on-vehicle battery 11 on the basis of a battery capacity in the new condition of the on-vehicle battery 11 and a current battery capacity. The measurement part 3 measures internal resistance R of the on-vehicle battery 11. The estimated deterioration degree calculation part 4 calculates an estimated deterioration degree SOHas an estimation value of the deterioration degree SOH on the basis of the internal resistance R. The point integration part 5 integrates a point P corresponding to a degree of certainty of the deterioration degree SOH in accordance with a difference between the deterioration degree SOH and the estimated deterioration degree SOH. The deterioration degree correction part 7 corrects the deterioration degree SOH when the point P exceeds a predetermined range.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a battery control device and a program for controlling an in-vehicle battery.

  2. Description of the Related Art Conventionally, a technique for estimating the degree of deterioration of a battery (secondary battery) mounted on an electric vehicle or a hybrid vehicle and calculating the charge amount and the charge rate of the battery based on this is known. As a technique for estimating the degree of deterioration, “SOH (State Of Health, degree of deterioration)” indicating how much the battery capacity has decreased as compared with the time of a new article can be mentioned. Further, the battery capacity of the battery can be grasped by, for example, integrating the charging current for bringing the battery from the fully discharged state to the fully charged state.

  On the other hand, it takes a very long time to charge the vehicle-mounted battery from the fully discharged state to the fully charged state, and it cannot be easily performed by the vehicle user. Therefore, various methods have been developed for estimating the degree of deterioration without bringing the battery into a fully discharged state. For example, a technique has been proposed in which parameters such as battery voltage, charge / discharge current, and battery temperature are detected by a sensor, and SOH is calculated based on these parameters. There has also been proposed a technique for estimating the internal resistance of a battery and measuring the state of charge based on the internal resistance (see Patent Documents 1 and 2).

JP 2012-042337 JP 2013-142649

  The parameters such as the battery voltage, charge / discharge current, and internal resistance include errors, and may vary greatly depending on the battery usage status and parameter detection status. For this reason, the degree of deterioration estimated based on the above parameters may change suddenly, and the estimation result may be difficult to stabilize. In addition, there is a problem in that it is difficult to improve the estimation accuracy of the degree of deterioration because of large variations in estimation results.

  One of the objects of the present case has been invented in view of the problems as described above, and is to provide a battery control device that can improve the estimation accuracy of the degree of deterioration. It should be noted that the present invention is not limited to this purpose, and is an operational effect that is derived from each configuration shown in “Mode for Carrying Out the Invention” to be described later. Can be positioned as a purpose.

  (1) The disclosed battery control device measures a deterioration degree calculation unit that calculates a deterioration degree of the in-vehicle battery based on a new battery capacity and a current battery capacity of the in-vehicle battery, and measures an internal resistance of the in-vehicle battery. And a measuring unit. Further, based on the internal resistance, an estimated deterioration degree calculating unit that calculates an estimated deterioration degree that is an estimated value of the deterioration degree, and the accuracy of the deterioration degree according to a difference between the deterioration degree and the estimated deterioration degree. And a point integration unit for integrating corresponding points. Furthermore, a deterioration degree correction unit that corrects the deterioration degree when the point exceeds a predetermined range is provided.

For example, if the difference between the deterioration level and the estimated deterioration level is small, it is determined that the accuracy of the deterioration level is high (high reliability), and the point integration unit does not increase or decrease the integrated value of the points so much. It is preferable. On the other hand, if the difference between the degradation level and the estimated degradation level is large, it is preferable that the accuracy of the degradation level is determined to be low (reliability is low), and the integrated value of the points is greatly increased or decreased.
Moreover, it is preferable that the said point integration part moves the integrated value of the said point to the plus direction, if the said estimated deterioration degree is larger than the said deterioration degree. On the other hand, if the estimated deterioration level is smaller than the deterioration level, it is preferable to move the integrated value of the points in the negative direction.

(2) The point integration unit increases the point when a value obtained by subtracting the deterioration degree from the estimated deterioration degree is positive, decreases the point when the value is negative, and corrects the deterioration degree. Preferably, the unit increases the degree of deterioration when the point is positive and decreases the degree of deterioration when the point is negative.
In addition, it is preferable that the said point integration part changes the said point largely, so that the said difference is large.

(3) It is preferable that the said measurement part measures the output side internal resistance at the time of discharge of the said vehicle-mounted battery, and the input side internal resistance at the time of charge.
(4) It is preferable that the estimated deterioration degree calculation unit calculates an output side estimated deterioration degree based on the output side internal resistance and calculates an input side estimated deterioration degree based on the input side internal resistance.
(5) A coefficient setting unit is provided that sets a first coefficient representing a degree of reflecting the output-side internal resistance in the point and a second coefficient representing a degree of reflecting the input-side internal resistance in the point. preferable.

(6) It is preferable that the coefficient setting unit sets the value of the second coefficient to be larger than the value of the first coefficient.
(7) The coefficient setting unit may set the first coefficient when the temperature of the in-vehicle battery is equal to or higher than a predetermined temperature to be larger than the first coefficient when the temperature is lower than the predetermined temperature. preferable.

(8) It is preferable that the coefficient setting unit sets the first coefficient and the second coefficient larger as the temperature of the in-vehicle battery is lower.
(9) The estimated deterioration degree calculation unit calculates the estimated deterioration degree based on a map that defines a relationship among the internal resistance, the charging rate of the in-vehicle battery, the temperature, and the deterioration degree (or the estimated deterioration degree). It is preferable to calculate.

  (10) The disclosed battery control program is a battery control program for controlling an in-vehicle battery, and includes a deterioration degree calculating means, a measuring means, an estimated deterioration degree calculating means, a point integrating means, and a computer as a deterioration degree correcting means. Is a program for making The deterioration degree calculating means calculates the deterioration degree of the in-vehicle battery based on the battery capacity of the in-vehicle battery when it is new and the current battery capacity. The measuring means measures an internal resistance of the in-vehicle battery. The estimated deterioration degree calculating means calculates an estimated deterioration degree that is an estimated value of the deterioration degree based on the internal resistance. The point accumulating unit accumulates points corresponding to the accuracy of the deterioration degree according to a difference between the deterioration degree and the estimated deterioration degree. The deterioration degree correcting means corrects the deterioration degree when the point exceeds a predetermined range.

  Using the estimated degree of deterioration estimated based on internal resistance, it is possible to correct the degree of deterioration appropriately by accumulating points corresponding to the accuracy of the degree of deterioration, and improve the calculation accuracy of the degree of deterioration. Can do.

It is a side view of the vehicle carrying the battery of a measuring object. It is a block diagram for demonstrating the structure of a battery control apparatus. (A)-(B) is a figure for demonstrating the calculation method of internal resistance R. FIG. (A)-(B) are maps that define the four-way relationship of internal resistance R, charge rate SOC, estimated degradation degree SOH _EST , and temperature T. (A)-(F) are the graphs which show the four-way relationship of internal resistance R, charge rate SOC, estimated deterioration degree SOH _EST , and temperature T. (A) ~ (D) is a graph showing the relationship between the temperature T and the first coefficient K ₁ and the second coefficient K _2. It is a flowchart regarding short-time discharge immediately before normal charging. It is a flowchart regarding correction | amendment of the deterioration degree at the time of normal charge.

  A battery control device 30 as an embodiment will be described with reference to the drawings. Note that the embodiment described below is merely an example, and there is no intention to exclude various modifications and technical applications that are not explicitly described in the following embodiment. Each configuration of the present embodiment can be implemented with various modifications without departing from the spirit thereof. Further, they can be selected as necessary, or can be appropriately combined.

[1. Definition of terms]
The battery control device 30 measures the battery capacity of the in-vehicle battery 11 mounted on the vehicle 10, estimates the degree of deterioration based on the new battery capacity and the current battery capacity, and installs the vehicle on the basis of the degree of deterioration. The battery 11 has a function of calculating a state of charge (SOC) and a cruising range. It is assumed that the degree of deterioration of the in-vehicle battery 11 is grasped by using the deterioration degree SOH (State Of Health) as an index.

  The degree of deterioration SOH is defined as a percentage of the current battery capacity [Ah] with respect to the battery capacity [Ah] when new. The deterioration degree SOH is 100 [%] when the in-vehicle battery 11 is new, and decreases as the deterioration of the in-vehicle battery 11 progresses. The value of the deterioration degree SOH can be measured at a car dealer or a maintenance shop. For example, by charging the vehicle-mounted battery 11 from a fully discharged state to a fully charged state and accumulating the current supplied during the charging, the current battery capacity is measured with high accuracy, and the degree of deterioration corresponding to this is measured. SOH can be calculated.

  The charge rate SOC is calculated based on a charge / discharge characteristic graph representing the relationship between the charge rate of the in-vehicle battery 11 and the voltage. The shape of the charge / discharge characteristic graph changes depending on the deterioration degree SOH. Therefore, the calculation accuracy of the charging rate SOC is improved by improving the estimation accuracy of the deterioration degree SOH. The value of the charging rate SOC corresponds to the percentage of the current charging capacity [Ah] with respect to the current battery capacity (full charging capacity) [Ah]. The charging rate SOC is 100 [%] when fully charged, and decreases as the stored power is consumed.

In the battery control device 30, “SOH _EST (estimated deterioration level)” is introduced as a parameter for correcting the deterioration level SOH. The estimated deterioration degree SOH _EST is an estimated value of the degree of deterioration of the in-vehicle battery 11 (an estimated value of the deterioration degree SOH), and is used to correct the deterioration degree SOH. This corrects the value of the deterioration degree SOH without measuring it at a car dealer or a maintenance shop, and improves the calculation accuracy of the charging rate SOC. The estimated deterioration degree SOH _EST is calculated by a method different from the deterioration degree SOH, and is calculated based on at least the internal resistance R of the in-vehicle battery 11. The estimated deterioration degree SOH _EST of the present embodiment is calculated based on the temperature T of the in-vehicle battery 11, the output side internal resistance R _OUT , the input side internal resistance R _IN , and the charge rate SOC.

The temperature T means the temperature of the in-vehicle battery 11 or a temperature correlated therewith. The temperature T of the present embodiment includes cell temperature (cell internal temperature, cell surface temperature), battery case internal temperature, battery case surface temperature, average temperature of these, and the like. The output-side internal resistance R _OUT means the internal resistance R during discharging of the in-vehicle battery 11, and the input-side internal resistance R _IN means the internal resistance R during charging. The output-side internal resistance R _OUT is obtained, for example, by operating an electrical load connected to the in-vehicle battery 11 and dividing the voltage change amount (decrease amount) ΔV by the current I. Similarly, the input-side internal resistance _RIN is obtained by, for example, dividing the voltage change amount (rise amount) ΔV when charging of the in-vehicle battery 11 is started by the current I.

The battery control device 30, two kinds of estimated deterioration degree SOH _EST during charging and the estimated degree of deterioration SOH _EST at the time of discharge of the battery 11 is calculated. Hereinafter, the former is also referred to as “output-side estimated deterioration degree SOH _EST ”, and the latter is also referred to as “input-side estimated deterioration degree SOH _EST ”. The estimated deterioration degree SOH _EST on the output side is calculated based on the temperature T, the output side internal resistance R _OUT , and the charge rate SOC. On the other hand, the estimated deterioration degree SOH _EST on the input side is calculated based on the temperature T, the input-side internal resistance R _IN , and the charge rate SOC.

These two types of estimated deterioration levels SOH _EST are used to set, calculate, and integrate “point P” that is a parameter corresponding to the accuracy of the deterioration level SOH. “Accuracy” means the certainty or degree of certainty (high reliability) of the current degree of degradation SOH. That is, the estimated deterioration degree SOH _EST is not used for directly reflecting the correction in the deterioration degree SOH as it is, but is not a substitute parameter for the deterioration degree SOH. The estimated deterioration degree SOH _EST is a parameter used to check how reliable the current deterioration degree SOH is. For example, if the difference between the deterioration degree SOH and the estimated deterioration degree SOH _EST is small, it is determined that the accuracy of the current deterioration degree SOH is high (high reliability), and the addition / subtraction amount of the point P is reduced. On the other hand, if the difference between the deterioration degree SOH and the estimated deterioration degree SOH _EST is large, it is determined that the accuracy of the current deterioration degree SOH is low (the reliability is low), and the addition / subtraction amount of the point P is increased. By adopting such a method, the higher the accuracy of the current deterioration degree SOH, the more difficult the point P changes.

If the estimated deterioration degree SOH _EST is larger than the deterioration degree SOH, the point P is preferably changed in the positive direction. If the estimated deterioration degree SOH _EST is smaller than the deterioration degree SOH, the point P is preferably changed in the negative direction. . Thereby, the increase / decrease direction in which the deterioration degree SOH should be corrected corresponds to the increase / decrease direction of the point P, and the correction calculation of the deterioration degree SOH becomes easy. For example, when the point P exceeds the predetermined range in the plus direction, the deterioration degree SOH may be corrected to increase. On the contrary, when the point P exceeds the predetermined range in the minus direction, the deterioration degree SOH may be corrected to decrease. As long as the accuracy of the current deterioration degree SOH remains high, the value of the point P hardly changes. In addition, even if the estimated deterioration degree SOH _EST values fluctuate before and after the deterioration degree SOH due to the error, the increase in point P due to the positive error is offset by the decrease in point P due to the negative error. Therefore, the point P stays near zero.

[2. Vehicle configuration]
The battery control device 30 is applied to the vehicle 10 equipped with the in-vehicle battery 11 shown in FIG. The vehicle 10 is an electric vehicle equipped with at least a traveling motor generator 12 (simply referred to as a motor 12). Alternatively, it is a hybrid vehicle equipped with an engine 14 for driving not only the motor 12 but also a motor generator 13 for power generation (simply called the generator 13). The engine 14 is a prime mover that drives the generator 13 to generate electric power, and is controlled so as to continue operation in a rotational speed region where engine efficiency is high as necessary.

Calculation of the estimated deterioration degree SOH _EST of the in-vehicle battery 11 and correction of the deterioration degree SOH are performed at the time of external charging by an external power supply facility. An inlet 25 (charging port) for connecting the vehicle 10 to an external power supply facility is provided on the side surface of the vehicle 10. The inlet 25 is provided with a normal charging socket that can be connected to a household outlet 27 using a charging cable 26 and a quick charging socket that can be connected to a charging stand 28. In the present embodiment, the control for correcting the deterioration level SOH during normal charging via the normal charging socket will be described in detail, but it is also possible to correct the deterioration level SOH during quick charging via the quick charging socket. In principle, it is also possible to correct the degree of deterioration SOH during charging using the power generated by driving the generator 13 with the engine 14 (during internal charging).

  As shown in FIG. 2, the motor 12 and the generator 13 are connected to the in-vehicle battery 11 via the inverter 15. The in-vehicle battery 11 is a secondary battery that serves as a power supply source for the motor 12, and is, for example, a lithium ion secondary battery, a lithium ion capacitor, a nickel hydrogen storage battery, an alkaline ion storage battery, or the like. Hereinafter, the DC circuit connected to the in-vehicle battery 11 is referred to as a battery circuit 20. The battery circuit 20 is provided with a contactor (circuit connection / disconnection switch) (not shown), and the charge / discharge current of the in-vehicle battery 11 is supplied and disconnected according to the connection / disconnection state of the contactor.

  The inverter 15 is a converter (DC-AC inverter) that mutually converts DC power on the vehicle-mounted battery 11 side and AC power on the motor 12 side. When the motor 12 is powered, alternating drive power is supplied from the in-vehicle battery 11 side to the motor 12 side. On the other hand, during the regeneration of the motor 12 or the power generation of the generator 13, DC charging power is supplied from the motor 12 side to the in-vehicle battery 11 side. The inverter 15 and the motor 12 and the generator 13 are connected by a three-phase AC power line.

  The battery circuit 20 is connected with a hot water heater 16 for air conditioning and an in-vehicle charger 17. The hot water heater 16 is a heater for heating hot water for heating and air conditioning, but can be used even when the air conditioner is not in operation. In the present embodiment, the hot water heater 16 is used as an electrical load for temporarily putting the vehicle-mounted battery 11 in a discharged state immediately before starting normal charging. The hot water heater 16 has a built-in PTC (Positive Temperature Coefficient) heater module, and the power consumption and current value can be adjusted by controlling the duty ratio of the control signal by the PWM method. In addition, when a plurality of heater modules are built in the hot water heater 16, the power consumption and the current value may be adjusted by changing the number of modules to be energized.

  The in-vehicle charger 17 is a charger (OBC, On Board Charger) that converts the power input from the external power supply facility during normal charging and charges the in-vehicle battery 11. Here, the AC power of several hundred volts supplied from the outside of the vehicle 10 is converted into DC power of several hundred volts, and the in-vehicle battery 11 is charged. Further, when the front end portion (charging gun) of the charging cable 26 is inserted into the outlet 27 and connected to the in-vehicle charger 17, it is determined that the in-vehicle charger 17 can perform normal charging, and the information is It is transmitted to the battery control device 30.

  The in-vehicle battery 11 is provided with a current sensor 21, a voltage sensor 22, and a battery temperature sensor 23 as sensors for acquiring parameters corresponding to the charge / discharge state. The current sensor 21 detects the current I (input / output current) of the in-vehicle battery 11, the voltage sensor 22 detects the voltage V of the in-vehicle battery 11, and the battery temperature sensor 23 detects the temperature T of the in-vehicle battery 11. Various types of information detected by these sensors 21 to 23 are transmitted to the battery control device 30 that controls the operating state and charge / discharge state of the in-vehicle battery 11.

  The battery control device 30 is an electronic control device (computer, ECU, Electronic Control Unit) having a function of measuring, calculating, and controlling the charge / discharge state, the charge rate SOC, the deterioration degree SOH, and the like of the in-vehicle battery 11. Connected to the in-vehicle network. Information on a plurality of battery modules and cells (for example, information on cell charge / discharge current, cell voltage, cell temperature, etc.) included in the in-vehicle battery 11 is transmitted to the battery control device 30, and these information are comprehensively managed. Is done. The battery control device 30 includes a processor, a memory, an interface device, and the like connected to each other via a bus.

  The processor is a processing device including, for example, a control unit (control circuit), an arithmetic unit (arithmetic circuit), a cache memory (register), and the like. The memory is a storage device that stores a program and working data, and includes a ROM (Read Only Memory), a RAM (Random Access Memory), a nonvolatile memory, and the like. The contents of the control performed by the battery control device 30 are recorded and stored in the memory as firmware or an application program. When the program is executed, the contents of the program are expanded in the memory space and executed by the processor.

  In addition to the various sensors 21 to 23 described above, a motor 12, a generator 13, an engine 14, an inverter 15, a hot water heater 16, an in-vehicle charger 17 and the like are connected on the in-vehicle network. Moreover, it is possible to connect an arbitrary electronic device to the in-vehicle network via a connector (not shown). Or it is possible to connect a vehicle-mounted network to arbitrary external networks via the communication apparatus which is not shown in figure.

[3. Control configuration]
The battery control device 30 records, saves and executes a battery control program 1 for measuring the battery capacity of the in-vehicle battery 11, estimating the degree of deterioration, and calculating the charging rate SOC based on the degree of deterioration. . Alternatively, the battery control program 1 is recorded and stored in a recording medium readable by the battery control device 30, and the battery control program 1 is read into the battery control device 30 and executed. In the present embodiment, the battery control program 1 is executed during normal charging of the in-vehicle battery 11.

  The battery control program 1 is provided with a deterioration level calculation unit 2, a measurement unit 3, an estimated deterioration level calculation unit 4, a point integration unit 5, a coefficient setting unit 6, and a deterioration level correction unit 7. These represent functions programmed as software. These functions can be realized by causing the processor of the battery control device 30 to read the battery control program 1 and executing arithmetic processing. However, these functions can also be realized by an electronic circuit (hardware). Alternatively, some of these functions may be hardware and the other may be software.

  The deterioration degree calculating unit 2 (deterioration degree calculating means) calculates the deterioration degree SOH of the in-vehicle battery 11 based on the battery capacity of the in-vehicle battery 11 when it is new and the current battery capacity. The deterioration degree SOH calculated here is a deterioration degree SOH obtained by a so-called conventional method. The new battery capacity is recorded in advance in the memory of the battery control device 30. The current battery capacity is a value measured at, for example, a car dealer or a maintenance shop. The deterioration degree SOH calculated by the deterioration degree calculation unit 2 is calculated based on the battery capacity measured when the in-vehicle battery 11 is fully discharged and charged to the full charge state.

The measuring unit 3 (measuring means) measures the internal resistance R of the in-vehicle battery 11. Here, the output side internal resistance R _OUT and the input side internal resistance R _IN are individually measured. The output-side internal resistance R _OUT can be measured at least while the vehicle-mounted battery 11 is discharged, and the input-side internal resistance R _IN can be measured at least while the vehicle-mounted battery 11 is charged. The measurement unit 3 of the present embodiment discharges the in-vehicle battery 11 for a short time immediately before starting normal charging, and measures the output-side internal resistance _ROUT . Thereafter, the input-side internal resistance _RIN is measured in a charging state immediately after starting normal charging. Incidentally, since the discharge load of the battery 11 can be relatively easily changed, the number of measurements of the output internal resistance R _OUT is a plurality of times, it is preferable to different discharge currents at each measurement. On the other hand, since the charging current cannot be freely changed, the number of times of measurement of the input side internal resistance _RIN may be one.

FIG. 3A is a diagram in which the relationship between the current I during discharge of the in-vehicle battery 11 and the voltage change amount (decrease amount) ΔV is measured three times, and points corresponding to the respective measurement results are plotted. V ₀ in the figure represents a voltage in a state where charging / discharging is not performed. Moreover, the subscripts of the current I and the voltage V are ordinal numbers indicating the measurement order. For example, it is assumed that the voltage V ₁ is detected during the discharge with the current I ₁ , the voltage V ₂ is detected during the discharge with the current I ₂ , and the voltage V ₃ is detected during the discharge with the current I ₃ . The voltage change amount (decrease amount) ΔV in each case is V ₀ -V ₁ , V ₀ -V ₂ , V ₀ -V ₃ . The output side internal resistance R _OUT corresponds to the slope of a straight line graph passing through the origin and each point. Therefore, the output side internal resistance R _OUT can be obtained by obtaining a regression line passing through the origin from the measurement result and calculating the slope thereof. Similarly, FIG. 3B is a diagram in which points corresponding to the current I ₄ and the voltage change amount (rise amount) ΔV (= V ₀ + V ₄ ) measured during charging of the in-vehicle battery 11 are plotted. The slope of the regression line passing through the origin corresponds to the input-side internal resistance _RIN .

The measurement of the voltage V ₀ is preferably carried out after a pause of several minutes to a sufficient time (time for neither charging nor discharging). When the number of measurements is multiple, it is preferable to provide a similar pause time between each measurement. The discharge time is about several seconds, and the charge time is about several tens of seconds to several minutes. In addition, cell balancer control (capacity equalization control) is stopped during charging so that only charging is performed. Thereby, the measurement result of the voltage V is easily stabilized, and the calculation accuracy of the internal resistance R is improved.

The estimated deterioration degree calculation unit 4 (estimated deterioration degree calculation means) is based on at least two types of internal resistances R (output side internal resistance R _OUT and input side internal resistance R _IN ) measured by the measurement unit 3. SOH _EST is calculated. Here, the output-side estimated degradation degree SOH _EST is calculated based on the output-side internal resistance R _OUT, the input-side estimated deterioration degree SOH _EST is calculated based on the input-side internal resistance R _IN. The estimated deterioration degree calculation unit 4 of the present embodiment is based on a map that defines the relationship among the charging rate SOC, the internal resistance R, the temperature T, and the deterioration degree SOH (or the estimated deterioration degree SOH _EST ) of the in-vehicle battery 11. Estimated degradation degree SOH _EST is calculated. Further, when calculating the estimated deterioration degree SOH _EST , a map (table) as shown in FIGS. 4A and 4B is used.

4A is an example of a calculation table for the output side estimated deterioration degree SOH _EST , and FIG. 4B is an example of a calculation table for the input side estimated deterioration degree SOH _EST . The former table defines the four-way relationship among the output-side internal resistance R _OUT , the charge rate SOC, the temperature T, and the output-side estimated degradation degree SOH _EST . The latter table defines the input-side internal resistance R _IN and the charge. A four-way relationship between the rate SOC, temperature T, and input side estimated deterioration degree SOH _EST is defined. Data that is not on the table may be calculated by interpolating or extrapolating the data on the table.

Instead of the above table, the estimated deterioration degree SOH _EST may be calculated using a map (graph) as shown in FIGS. The relationships defined in these graphs are the same as the relationships defined in the tables of FIGS. 4 (A) and 4 (B). Alternatively, the estimated deterioration degree SOH _EST may be defined as a function of the internal resistance R, the charging rate SOC, and the temperature T. In this case, the function of the output side estimated deterioration degree SOH _{EST and} the function of the input side estimated deterioration degree SOH _EST may be defined separately.

The point integration unit 5 (point integration means) is a point corresponding to the accuracy of the degradation level SOH according to the difference between the degradation level SOH of the in-vehicle battery 11 and the estimated degradation level SOH _EST calculated by the estimated degradation level calculation unit 4. In addition to setting P, the points P are accumulated and counted. Here, the point P is set based on each of the output side estimated deterioration degree SOH _EST and the input side estimated deterioration degree SOH _EST . Further, the sign of the set point P may be positive or negative. Therefore, the value of the point P integrated here does not necessarily increase monotonously (or decrease monotonically).

In the present embodiment, a difference A _OUT is calculated by subtracting the current deterioration degree SOH from the output side estimated deterioration degree SOH _EST, and a difference A _IN is calculated by subtracting the current deterioration degree SOH from the input side estimated deterioration degree SOH _EST. To do. Here, if the difference A _OUT on the output side is equal to or greater than the positive predetermined value A ₁ , the predetermined change point B is added to the point P, and if the difference A _OUT on the output side is equal to or greater than the negative predetermined value −A ₁ , A predetermined change point B is subtracted from the point P. The same applies to the difference A _IN input side, the difference A _IN input side if a predetermined positive value A ₂ or more, by adding a predetermined change point B to the point P, the difference A _IN input side is negative if the predetermined value -A ₂ below, subtracts a predetermined change point B from point P. That is, the point P is increased when the value obtained by subtracting the current deterioration level SOH from the estimated deterioration level SOH _EST is positive, and the point P is decreased when the value is negative.

The predetermined values A ₁ and A ₂ are, for example, about several [%] (number [Ah] in terms of battery capacity). The change point B may be a fixed value (for example, 1.0) set in advance, but is preferably a variable value determined according to the state of the in-vehicle battery 11. For example, the change point B may be a value obtained by multiplying the fixed value by the coefficient K, and the coefficient K may be set according to the state of the in-vehicle battery 11.

The coefficient setting unit 6 (coefficient setting means) sets the coefficient K described above. Here, the first coefficient K ₁ and the second coefficient K ₂ are set. The first coefficient K ₁ represents the degree to which the output side internal resistance R _OUT is reflected at the point P, and is a parameter corresponding to the magnitude of the influence of the output side estimated deterioration degree SOH _{EST on} the accuracy of the deterioration degree SOH. It is. The second coefficient K ₂ represents the degree to which the input-side internal resistance R _IN is reflected at the point P. For example, the input-side estimated deterioration degree SOH _EST has a large influence on the accuracy of the deterioration degree SOH. The corresponding parameter.

The first coefficient K ₁ and the second coefficient K ₂ are set based on the temperature T, for example. The first coefficient K ₁ and the second coefficient K ₂ may be set based on the charging rate SOC, the internal resistance R, the estimated deterioration degree SOH _{EST, and the} like of the in-vehicle battery 11. When the change point B is a fixed value, the coefficient K is also set to a fixed value (for example, 1.0). When the change point B is a variable value, the coefficient K is also a variable value. The first coefficient K ₁ and the second coefficient K ₂ can be set as variable values independent of each other according to the characteristics of the in-vehicle battery 11. For example, the in-vehicle battery 11 having the characteristics shown in the maps of FIGS. 5A to 5F has the following characteristics.

Features 1. The graph showing the relationship between the estimated degradation degree SOH _EST and the internal resistance R changes depending on the charging rate SOC, but the variation of the estimated degradation degree SOH _{EST with} respect to the input side internal resistance R _IN varies with the output side internal resistance R _OUT . Estimated degradation level is smaller than variation of SOH _EST .
Feature 2. Regarding the graph shape showing the relationship between the output-side internal resistance R _OUT and the estimated deterioration degree SOH _EST , when the normal temperature (0 ° C. or higher) and the charge rate SOC are low, there is a tendency different from other cases.
Feature 3. The lower the temperature T, the smaller the slope of the graph representing the relationship between the estimated deterioration degree SOH _EST and the internal resistance R, and the smaller the fluctuation of the estimated deterioration degree SOH _{EST with} respect to the calculation error of the internal resistance R.

Therefore, it is conceivable to set the coefficient K as follows.
Setting 1. Setting the second coefficient K ₂ to the first coefficient K ₁ or more in size.
Setting 2. A first coefficient K ₁ when the temperature T is the predetermined temperature T ₀ or more (or eg 0 ° C.) and the SOC is lower than a predetermined charging rate, set larger than the first coefficient K ₁ of the other cases.
Setting 3. The lower the temperature T, the larger the first coefficient K ₁ and the second coefficient K ₂ are set.

Setting 1 is a setting example in which the input side estimated deterioration degree SOH _EST is more important than the output side estimated deterioration degree SOH _EST . The relationship between the coefficient K and the temperature T in setting 1 is illustrated in FIGS. 6 (A) and 6 (B). Setting 2 is a setting example that places emphasis on the solid line graphs of FIGS. The relationship between the coefficient K and the temperature T in setting 2 is illustrated in FIG. Setting 3 is a setting example that places emphasis on the estimated deterioration degree SOH _EST calculated at a low temperature. The relationship between the coefficient K and the temperature T in setting 3 is illustrated in FIG. In any setting, an effect of improving the accuracy of integrating the point P and the correction accuracy of the deterioration degree SOH can be expected. However, the measurement error of the internal resistance R increases at low temperatures, and the accuracy of the estimated deterioration degree SOH _EST can also decrease. In such a case, by decreasing the first coefficient K ₁ and the second coefficient K ₂ as the temperature T is lower, it is possible to prevent a decrease in the accuracy of the estimated deterioration degree SOH _EST .

The deterioration degree correction unit 7 (deterioration degree correction means) corrects the deterioration degree SOH when the point P integrated by the point integration unit 5 exceeds a predetermined range. The correction direction of the deterioration degree SOH corresponds to the sign of the point P. That is, when the point P is positive, the deterioration degree SOH is corrected to increase, and when the point P is negative, the deterioration degree SOH is corrected to decrease. In the present embodiment, when the point P exceeds the positive predetermined point P ₀ , correction is added to increase the deterioration degree SOH by several [%]. On the other hand, when the point P falls below the negative predetermined point −P ₀ , correction for reducing the deterioration degree SOH by several [%] is applied. The increase / decrease amount of the deterioration degree SOH is about 0.5 [Ah] in terms of battery capacity. The deterioration degree SOH corrected here is recorded and stored in a memory in the battery control device 30. Thereafter, the charging rate SOC and the cruising range of the in-vehicle battery 11 are calculated based on the corrected deterioration degree SOH.

[4. flowchart]
7 and 8 are flowcharts for explaining the contents of the battery control program 1 executed by the battery control device 30. FIG. FIG. 7 corresponds to the control related to temporary discharge that is performed immediately before normal charging. When the in-vehicle battery 11 is connected to an external power supply for normal charging via the charging cable 26 (step A1), information on the charging rate SOC and temperature T of the in-vehicle battery 11 at that time is recorded (step A2). Before starting normal charging, a short-time discharge is performed for measuring the output-side internal resistance _ROUT (step A3).

First, the measurement unit 3 measures the voltage V _{0 in a} state where charging / discharging is not performed. Next, only one of the plurality of heater modules built in the hot water heater 16 operates for several seconds, and the current I ₁ and the voltage V ₁ are measured (step A4). At this time, the voltage change amount ΔV is V ₀ -V ₁ . After a several minutes to sufficiently about downtime, current I is changed by actuating several seconds two heater modules (step A6), the voltage V ₂ is measured again (step A4). When such measurement is repeated three times (step A5), the output-side internal resistance _ROUT is calculated (step A7).

The estimated deterioration degree calculation unit 4 calculates the output side estimated deterioration degree SOH _EST based on, for example, a map as shown in FIG. 4A (step A8). The coefficient setting unit 6, the first coefficient K ₁ is set, for example, based on the temperature T (step A9). Further, the point integration unit 5 calculates a difference A _OUT that is a value obtained by subtracting the deterioration degree SOH from the output side estimated deterioration degree SOH _EST (step A10). Here, it is determined whether or not the difference A _OUT is equal to or greater than a positive predetermined value A ₁ (step A11). If this condition is satisfied, a predetermined change point B is added to the point P (step A11). A13). The change point B has a size corresponding to the first coefficient K ₁ (here, 1 × K ₁ ).

On the other hand, if the difference A _OUT is positive smaller than the predetermined value A _1, the difference A _OUT is whether or not a predetermined negative value -A ₁ or less is determined (step A12), if this condition is satisfied The predetermined change point B (here 1 × K ₁ ) is subtracted from the point P (step A14). When the difference A _OUT exceeds the negative predetermined value −A ₁ , the value of the point P is maintained as it is. After the determination of the difference A _OUT is finished, the short-time discharge is finished (step A15), and the control proceeds to the flowchart of FIG.

FIG. 8 corresponds to the control performed immediately after the start of normal charging. First, normal charging is started (step B1), and when several tens of seconds to several minutes have elapsed, the current I ₄ and the voltage V ₄ are measured (step B2). At this time, the voltage change amount ΔV is V ₀ + V ₄ . Further, the input side internal resistance _RIN is calculated in the measuring unit 3 (step B3), the estimated deterioration degree calculating unit 4 calculates the input side estimated deterioration degree SOH _EST (step B4), and the coefficient setting unit 6 A two coefficient K ₂ is set (step B5).

The point integration unit 5 calculates a difference A _IN that is a value obtained by subtracting the deterioration degree SOH from the input-side estimated deterioration degree SOH _EST (step B6). Here, it is determined whether or not the difference A _IN is equal to or greater than the positive predetermined value A ₂ (step B7). If this condition is satisfied, the predetermined change point B is added to the point P (step B7). B9). The change point B has a size (here 1 × K ₂ ) corresponding to the second coefficient K ₂ . On the other hand, if the difference A _IN is positive smaller than the predetermined value A _2, the difference A _IN is whether or not a predetermined negative value -A ₂ or less is determined (step B8), if this condition is satisfied The predetermined change point B (here, 1 × K ₂ ) is subtracted from the point P (step B10). If the difference A _IN exceeds the negative predetermined value −A ₂ , the value of the point P is maintained as it is.

When the addition / subtraction of the point P based on the two types of estimated deterioration degrees SOH _EST is completed, the deterioration degree correction unit 7 determines whether or not the point P exceeds the positive predetermined point P ₀ (step B11). When this condition is satisfied, it is determined that the current deterioration degree SOH is smaller than the actual deterioration degree, and a positive correction is added to the deterioration degree SOH (step B13). On the other hand, if the point P is positive predetermined point P ₀ or less, the point P is equal to or less than a negative predetermined point -P ₀ is determined (step B12). When this condition is satisfied, it is determined that the current deterioration degree SOH is larger than the actual deterioration degree, and a negative correction is added to the deterioration degree SOH (step B14). The information on the degree of deterioration SOH corrected here is recorded and stored in a memory in the battery control device 30.

When the point P is equal to or greater than the negative predetermined point −P _0, it is determined that the accuracy of the current deterioration level SOH is high (high reliability), and correction for the deterioration level SOH is not performed. . That is, the deterioration degree SOH is not corrected unless the point P exceeds a predetermined range (a range from the negative predetermined point −P ₀ to the positive predetermined point P ₀ ). When such processing ends, normal charging is continued (step B15).

[5. effect]
(1) In the battery control device 30 described above, the points P corresponding to the accuracy of the deterioration degree SOH are integrated using the estimated deterioration degree SOH _EST estimated based on the internal resistance R of the in-vehicle battery 11. Further, the correction of the deterioration degree SOH is performed based on this point P. By adopting such a correction method, it is possible to appropriately correct the deterioration degree SOH, and it is possible to improve the calculation accuracy of the deterioration degree SOH.

If, by employing a correction technique to reflect directly the degradation degree SOH estimation deterioration degree SOH _EST, calculation error of the estimated degree of degradation SOH _EST is adversely affect the deterioration degree SOH, a rather precise degree of deterioration SOH It can be reduced. In response to such a problem, according to the battery control device 30 of the present embodiment, the calculation error of the estimated deterioration degree SOH _EST can be offset by the increase and decrease of the point P. Therefore, it is possible to improve the calculation accuracy of the deterioration degree SOH, and consequently improve the calculation accuracy of the charging rate SOC and the cruising range.

(2) In the battery control device 30 described above, the point P increases when the difference A _{OUT obtained} by subtracting the current deterioration degree SOH from the output-side estimated deterioration degree SOH _EST is positive, and the point P decreases when it is negative. It is like that. Similarly, the difference A _IN from the input side estimated deterioration degree SOH _EST by subtracting the current degree of deterioration SOH point P is increased in the case of a positive, the point P is decreased in the case of negative. In this way, by correlating the difference A _OUT , A _IN , which is a value obtained by subtracting the deterioration degree SOH from the estimated deterioration degree SOH _EST, and the change direction of the point P, the direction and point where the deterioration degree SOH should be corrected The positive and negative of P can be rationally associated. For example, it can be considered that the degree of deterioration SOH should be corrected in the positive direction as the point P increases in the positive region. On the other hand, it can be considered that the degree of deterioration SOH should be corrected in the minus direction as the point P decreases in the negative region. Therefore, the deterioration degree SOH can be corrected appropriately.

(3) In the battery control device 30 described above, the output-side internal resistance R _OUT when the vehicle-mounted battery 11 is discharged and the input-side internal resistance R _IN when charging is measured. By referring to the information of these two types of internal resistances R _OUT and R _IN in combination, the degree of deterioration of the in-vehicle battery 11 can be grasped more accurately, and the calculation accuracy of the degree of deterioration SOH can be improved. it can.

(4) In the battery control device 30 described above, two types of estimated deterioration levels SOH _EST (output side estimated deterioration level SOH _EST and input side estimated deterioration level SOH _EST ) corresponding to two types of internal resistances R _OUT and R _IN are obtained. It is calculated and each estimated deterioration degree SOH _EST is compared with the current deterioration degree SOH. By such control, the accuracy of the deterioration degree SOH can be grasped with higher accuracy, and the calculation accuracy of the deterioration degree SOH can be improved.

(5) In the battery control device 30 described above, two types of coefficients K ₁ and K ₂ corresponding to the two types of internal resistances R _OUT and R _IN are set. Thus, the calculation accuracy of the point P can be improved by individually setting the degree of reflecting the output side internal resistance R _OUT to the point P and the degree of reflecting the input side internal resistance R _IN to the point P. . Therefore, it becomes easy to correct the deterioration degree SOH more appropriately, and the calculation accuracy of the deterioration degree SOH can be further improved.

(6) When the second coefficient K ₂ is set to be larger than the first coefficient K ₁ (that is, when K ₂ ≧ K ₁ ), the input side estimated deterioration degree SOH _EST is output side estimated. from being more important than the degradation degree SOH _EST, it is possible to reduce the influence of variations in the estimated degradation degree SOH _EST by charging rate SOC. This variation in the input-side estimated degradation degree SOH _EST is because with small characteristic than the variation of the output-side estimated degradation degree SOH _EST. By setting the coefficient K using such characteristics, the calculation accuracy of the estimated deterioration degree SOH _EST can be improved, and the calculation accuracy of the deterioration degree SOH can be improved.

(7) As shown in FIG. 6C, the first coefficient K ₁ when the temperature T of the in-vehicle battery 11 is equal to or higher than the predetermined temperature T ₀ (in the case of normal temperature) is less than the predetermined temperature T _0. If set greater than the first coefficient K ₁ can enhance the accuracy of the estimated degree of degradation SOH _EST, it is possible to improve the calculation accuracy of the deterioration degree SOH. This is because the characteristics of the output side estimated deterioration degree SOH _EST change with the temperature T as a boundary at the predetermined temperature T ₀ . For example, as shown in FIGS. 5A, 5C, and 5E, when the temperature T is equal to or higher than a predetermined temperature T ₀ , the relationship between the estimated deterioration degree SOH _EST and the output-side internal resistance R _OUT is charged. It tends to vary depending on the rate SOC. Considering these characteristics, the results at room temperature are more important than those at low temperatures, making it easier to identify changes in the estimated degradation level SOH _EST depending on the internal resistance R, and calculating the degradation level SOH. Accuracy can be improved.

(8) As shown in FIGS. 5A to 5F, as the temperature T of the in-vehicle battery 11 is lower, the change gradient of the estimated deterioration degree SOH _{EST with} respect to the internal resistance R becomes a gentler gradient. Therefore, by setting the first coefficient K ₁ and the second coefficient K ₂ at a low temperature to be larger than the first coefficient K ₁ and the second coefficient K ₂ at a high temperature, the estimated deterioration degree SOH _EST calculated at a low temperature can be obtained. Emphasized. That is, the fluctuation of the estimated deterioration degree SOH _{EST with} respect to the calculation error of the internal resistance R is reduced, and correction that causes the deterioration degree SOH to change suddenly is suppressed. Therefore, as shown in FIG. 6D, by setting the first coefficient K ₁ and the second coefficient K _{2 to} be larger as the temperature T of the in-vehicle battery 11 is lower, the estimated deterioration degree SOH _EST The calculation accuracy can be improved, and the calculation accuracy of the deterioration degree SOH can be improved.

(9) In the battery control device 30 described above, the relationship between the charging rate SOC, the internal resistance R (the output side internal resistance R _OUT , the input side internal resistance R _IN ), the temperature T, and the deterioration degree SOH of the in-vehicle battery 11 is defined. Based on the map, an estimated deterioration degree SOH _EST is calculated. The estimated degree of deterioration SOH value of _EST calculated here, not only the internal resistance R of the battery 11, because the influence of the charging rate SOC and the temperature T at that time is reflected, estimated deterioration degree SOH _EST of The calculation accuracy can be improved, and the calculation accuracy and correction accuracy of the deterioration degree SOH can be improved. If a map (table, graph, function, etc.) as described above is prepared in advance, the estimated deterioration degree SOH _EST can be easily calculated.

[6. Modified example]
In the above-described embodiment, the internal resistance R of the in-vehicle battery 11 is exemplified by calculating two types of the output-side internal resistance _ROUT and the input-side internal resistance _RIN , but one of the internal resistances R is used. The estimated deterioration degree SOH _EST may be calculated. Alternatively, the estimated deterioration degree SOH _EST may be calculated using an average value or an intermediate value between the output side internal resistance R _OUT and the input side internal resistance R _IN . By calculating the estimated deterioration degree SOH _EST based on at least the internal resistance R and accumulating the points P according to the difference between this and the deterioration degree SOH, the same effects as in the above-described embodiment can be obtained.

The control performed in the above-described embodiment is performed not only during normal charging of the vehicle 10, but also during rapid charging by a rapid charging facility or during charging by regenerative power generation during traveling (charging using generated power generated by the generator 13). It is also possible to implement However, when measuring the internal resistance R, it is desirable to stabilize the charge / discharge state of the in-vehicle battery 11. Further, in the above-described embodiment, following the control of calculating the output side internal resistance R _OUT, although the control for correcting the control and deterioration degree SOH for calculating an input-side internal resistance R _IN is being performed, these The three types of control may be performed individually.

DESCRIPTION OF SYMBOLS 1 Battery control program 2 Deterioration degree calculation part (Deterioration degree calculation means)
3 Measuring unit (measuring means)
4 Estimated degradation level calculation unit (estimated degradation level calculation means)
5 Point accumulator (Point accumulator)
6 Coefficient setting part (coefficient setting means)
7 Deterioration degree correction unit (Deterioration degree correction means)
DESCRIPTION OF SYMBOLS 10 Vehicle 11 Car-mounted battery 16 Hot water heater 21 Current sensor 22 Voltage sensor 23 Battery temperature sensor 30 Battery control apparatus
SOC charge rate
SOH degradation
SOH _EST estimated degradation
T temperature
R Internal resistance
R _OUT output side internal resistance
R _IN Input side internal resistance
P point

Claims (10)

A deterioration degree calculating unit for calculating a deterioration degree of the in-vehicle battery based on a new battery capacity of the in-vehicle battery and a current battery capacity;
A measuring unit for measuring the internal resistance of the in-vehicle battery;
Based on the internal resistance, an estimated deterioration degree calculating unit that calculates an estimated deterioration degree that is an estimated value of the deterioration degree;
A point integration unit that integrates points corresponding to the accuracy of the deterioration degree according to the difference between the deterioration degree and the estimated deterioration degree;
A deterioration degree correction unit that corrects the deterioration degree when the point exceeds a predetermined range;
A battery control device comprising: The point integration unit increases the point when the value obtained by subtracting the deterioration degree from the estimated deterioration degree is positive, and decreases the point when the value is negative,
The battery control device according to claim 1, wherein the deterioration degree correction unit increases the deterioration degree when the point is positive and decreases the deterioration degree when the point is negative. 3. The battery control device according to claim 1, wherein the measurement unit measures an output-side internal resistance during discharging of the in-vehicle battery and an input-side internal resistance during charging. 4. The estimated deterioration degree calculation unit calculates an output side estimated deterioration degree based on the output side internal resistance, and calculates an input side estimated deterioration degree based on the input side internal resistance. Battery control device. And a coefficient setting unit configured to set a first coefficient representing a degree of reflecting the output-side internal resistance to the point and a second coefficient representing a degree of reflecting the input-side internal resistance to the point. The battery control device according to claim 3 or 4. The battery control device according to claim 5, wherein the coefficient setting unit sets the value of the second coefficient to be larger than the value of the first coefficient. The coefficient setting unit sets the first coefficient when the temperature of the in-vehicle battery is equal to or higher than a predetermined temperature to be larger than the first coefficient when the temperature is lower than the predetermined temperature. The battery control device according to claim 5 or 6. The battery control according to any one of claims 5 to 7, wherein the coefficient setting unit sets the first coefficient and the second coefficient larger as the temperature of the in-vehicle battery is lower. apparatus. The estimated deterioration degree calculation unit calculates the estimated deterioration degree based on a map that defines a relationship among the internal resistance, a charging rate of the on-vehicle battery, a temperature, and the deterioration degree. The battery control device according to any one of 1 to 8. A battery control program for controlling an in-vehicle battery,
Deterioration degree calculating means for calculating the deterioration degree of the in-vehicle battery based on the battery capacity of the in-vehicle battery when new and the current battery capacity;
Measuring means for measuring the internal resistance of the in-vehicle battery;
An estimated deterioration degree calculating means for calculating an estimated deterioration degree that is an estimated value of the deterioration degree based on the internal resistance;
Point integration means for integrating points corresponding to the accuracy of the deterioration degree according to the difference between the deterioration degree and the estimated deterioration degree;
A program for causing a computer to function as deterioration degree correction means for correcting the deterioration degree when the point exceeds a predetermined range.

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