JP6607353B2 - Vehicle and its battery state detection system - Google Patents

Description

  The present invention relates to a vehicle and a battery state detection system thereof, and in particular, taking into account the positive electrode active material density specific to the battery type and specifications, the accumulated discharge amount during vehicle travel and the deterioration degree increment value per unit discharge amount The present invention relates to a vehicle for determining the degree of deterioration of an in-vehicle lead battery during traveling of the vehicle and a battery state detection system thereof.

  In recent years, vehicles equipped with automatic engine stop and restart (ISS: idle stop / start) functions have become widespread in order to cope with the reduction of exhaust gas generated by engine cars, and in-vehicle lead-acid batteries are kept in a state where idling can be stopped. Technology is desired.

  That is, in an automobile (vehicle) equipped with an ISS, loads such as an air conditioner and a car stereo while the engine is stopped are all covered by power from the lead battery. For this reason, the deep discharge of a lead battery increases compared with the past, and it exists in the tendency for the charge condition of a lead battery to fall.

  Since the output of the lead battery depends on its state of charge, if the state of charge of the lead battery drops while the engine is stopped, it will not be possible to obtain sufficient output to start the engine, making it impossible to restart after stopping the engine. There is.

  Therefore, in order to maintain a state where the engine can be restarted, the charge state of the lead battery (for example, SOC: State Of Charge) is calculated (estimated) and the presence or absence of output necessary for engine start is monitored. When there is an output required for starting, idling stop is permitted, but when there is no output necessary for starting the engine, idling stop is prohibited and a signal such as charging a lead battery is transmitted to the vehicle computer. There is a need.

  In addition, since lead batteries deteriorate due to repeated charge and discharge, and the deteriorated lead batteries are expected to have a smaller remaining capacity during driving, the engine is restarted compared to new lead batteries. The risk of being unable to do so increases. Therefore, by calculating the degree of deterioration of the lead battery, it is determined whether the lead battery holds the electric capacity necessary for starting the engine, and if not, a signal for prompting replacement is transmitted to the computer on the vehicle side or the user side. It is desirable.

  As a technology for judging deterioration of an in-vehicle lead battery, Patent Document 1 discloses a technique for separately calculating a charge current and a discharge current flowing through a lead battery and calculating a deterioration degree or a health condition (SOH) from a charge / discharge balance. ing. However, since Patent Document 1 does not consider that the deterioration of the lead battery is affected by the depth of discharge DOD and the ambient temperature, the degree of deterioration SOH cannot be accurately estimated.

  In response to such a technical problem, Patent Document 2 discloses that the deterioration degree increment is calculated when the deterioration degree due to the discharge of the lead battery is calculated using the discharge amount of the lead battery and the deterioration degree increment per unit discharge amount. A technique for determining the depth of discharge DOD during travel as a function of temperature and temperature is disclosed.

Japanese Unexamined Patent Publication No. 2006-10601 Japanese Patent No. 5338807

  In Patent Literature 2, the deterioration degree increment is obtained as a function of the depth of discharge DOD and the temperature when the vehicle travels, but according to the results of experiments by the inventors, the deterioration degree increase also depends on the positive electrode active material density of the lead battery, Even if the batteries are the same type, the density of the positive electrode active material is different if the size and capacity are different.

  Therefore, regardless of the difference in the size and capacity of the lead-acid battery in the vehicle, that is, the positive electrode active material density, if the deterioration degree increment is uniformly calculated as a function of the depth of discharge and the temperature, the deterioration degree SOH can still be estimated accurately. Can not.

  The object of the present invention is to solve the above technical problem and minimize the man-hours for design and development, while accurately reflecting the density of the positive electrode active material in the calculation of the increase in the degree of deterioration of the lead battery. An object of the present invention is to provide a vehicle that can be estimated and a battery state detection system thereof.

  In order to achieve the above object, the present invention provides a battery state detection system that obtains the degree of deterioration of an in-vehicle battery based on the amount of discharge during vehicle travel and the degree of deterioration per unit discharge amount. It is characterized in that it is equipped.

  (1) Means for obtaining a deterioration degree increment value during vehicle traveling assuming that the in-vehicle battery is a standard battery, means for correcting the deterioration degree increment value based on the positive electrode active material density specific to the in-vehicle battery, and the correction And means for determining the degree of deterioration of the in-vehicle battery based on the subsequent deterioration degree increment value.

  (2) comprising a means for determining the depth of discharge of the in-vehicle battery when the vehicle is running, and a deterioration degree increment value map storing the relationship between the discharge depth of the standard battery and the deterioration degree increment value for each temperature, the deterioration degree increment The means for obtaining a value obtains the deterioration degree increment value by applying the temperature of the in-vehicle battery and the depth of discharge to the deterioration degree increment value map.

  (3) The active material density correction coefficient map storing the relationship between the discharge depth and the active material density correction coefficient for each positive electrode active material density is provided, and the means for correcting the deterioration degree increment value is a positive electrode active material of an in-vehicle battery. The density and the depth of discharge are applied to the active material density correction coefficient map to obtain an active material density correction coefficient, and the deterioration based on the active material density correction coefficient, the full charge capacity of the standard battery, and the full charge capacity of the in-vehicle battery The degree increment value was corrected.

  According to the present invention, the following effects are achieved.

  (1) When calculating the degree of deterioration of a lead battery using the discharge amount and the increment of deterioration per unit discharge amount, the density of the positive electrode active material of the in-vehicle battery can be reflected in the increment of deterioration. Can be calculated more accurately.

  (2) In calculating the deterioration level of the lead battery using the discharge amount and the deterioration degree increment per unit discharge amount, the deterioration degree increment is obtained as a function of the discharge depth DOD and the temperature when the vehicle travels, and the discharge depth DOD Since the positive electrode active material density of the lead battery is reflected in the above, the deterioration degree of the in-vehicle lead battery can be accurately calculated regardless of the positive electrode active material density.

  (3) A map for obtaining the degree of deterioration increment from the depth of discharge DOD and temperature is created only for the standard battery.For in-vehicle batteries of other sizes and capacities that differ from the standard battery and positive electrode active material density, the positive electrode active Since the correction factor obtained from the material density and the discharge depth DOD is used to correct the increase in the deterioration degree of the standard battery, the man-hour for designing the map for each lead battery having a different positive electrode active material density is not required.

It is the functional block diagram which showed the structure of the battery state detection system which concerns on one Embodiment of this invention. It is the block diagram which showed the function which estimates the degradation degree SOH based on the discharge amount of an vehicle-mounted battery, the frequency | count of discharge, temperature, and a full charge capacity. It is the figure which showed an example of the deterioration degree increment value map. It is the figure which showed an example of the active material density correction coefficient map.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1 is a functional block diagram showing a configuration of a main part of a battery state detection system 1 according to an embodiment of the present invention. Here, a gasoline engine vehicle equipped with a lead battery 12 having an ISS function is shown. Application will be described as an example.

  The battery state detection system 1 includes a temperature sensor 2 such as a thermistor for measuring the temperature of the lead battery 12, a voltage measuring unit 3 having a differential amplifier circuit or the like and connected to an external terminal of the lead battery 12, a hall element, and the like. A microcomputer (hereinafter referred to as a microcomputer) 10 that detects the battery state of the current sensor 4 and the lead battery 12 is a main component.

  The lead battery 12 has a substantially rectangular battery case serving as a battery container, and a total of six electrode plate groups are accommodated in the battery case. As the material of the battery case, for example, a polymer resin such as polyethylene (PE) can be used. Each electrode plate group is formed by laminating a plurality of negative plates and positive plates with a separator interposed therebetween, and the cell voltage is 2.0V. For this reason, the nominal voltage of the lead battery 12 is set to 12V. The upper part of the battery case is bonded or welded to an upper lid made of a polymer resin such as PE that seals the upper opening of the battery case. A rod-like positive electrode terminal and a negative electrode terminal for supplying electric power to the outside using the lead battery 12 as a power source are erected on the upper lid. In addition, the temperature sensor mentioned above is being fixed to the side part or bottom face part of a battery case.

  A positive terminal of the lead battery 12 is connected to a central terminal of an ignition switch (hereinafter, IGN) 5 through a current sensor 4. The IGN5 has an OFF terminal, ON / ACC terminal, and START terminal in addition to the central terminal, and the central terminal and any of the OFF, ON / ACC, and START terminals can be switched in a rotary manner. .

  The START terminal is connected to an engine starting cell motor (starter) 9. The cell motor 9 can transmit a rotational driving force to the rotation shaft of the engine 8 via a clutch mechanism (not shown). The ON / ACC terminal is connected to one end of a generator 7 that generates electricity by the rotation of the engine 8 through an auxiliary device 6 such as an air conditioner, a radio, a lamp, and a regulator including a rectifying element that allows current flow in one direction. ing. That is, the anode side of the regulator is connected to one end of the generator 7, and the cathode side is connected to the ON / ACC terminal.

  The rotating shaft of the engine 8 can transmit power to the generator 7 via a clutch mechanism (not shown). For this reason, when the engine 8 is in a rotating state, the generator 7 is operated via the clutch mechanism, and the generated power is supplied (charged) to the auxiliary machine 6 and the lead battery 12. The OFF terminal is not connected to either.

  The output of the voltage measuring unit 3 is connected to an A / D converter built in the microcomputer 10. The outputs of the temperature sensor 2 and the current sensor 4 are connected to an A / D converter built in the microcomputer 10, respectively. For this reason, the microcomputer 10 can take in the voltage and temperature of the lead battery 12 and the current flowing through the lead battery 12 as digital values every predetermined time. The microcomputer 10 can communicate with the host vehicle control system 11 via the I / O.

  The microcomputer 10 functions as a CPU that functions as a central processing unit, a ROM that stores basic control programs for the battery state detection system 12, program data such as maps and mathematical formulas described later, and a work area for the CPU and temporarily stores the data. It is configured to include RAM to store, nonvolatile EEPROM, etc.

  The other end of the generator 7, the cell motor 9 and the auxiliary machine 6, the negative terminal of the lead battery 12, and the microcomputer 10 are each connected to the ground (the same potential as the chassis of the automobile). Note that the microcomputer 10 of the present embodiment samples the voltage, current, and temperature at predetermined time intervals (for example, the voltage and current are each 2 milliseconds and the temperature is 1 second), and the sampling result is stored in the RAM. . Further, regarding the current, the integrated values are calculated separately for the discharge current and the charge current.

  The CPU mounted on the microcomputer 10 determines the terminal position based on the voltage of the IGN 5, and further detects the engine state. If the IGN 5 is a type that outputs a signal representative of the terminal position, the engine state may be detected based on the signal or a signal from the vehicle control system 11. In general, in an automobile having an internal combustion engine such as a gasoline engine car or a diesel engine car, electric power is supplied from a lead battery and a cell motor is rotated to start the engine.

  When a predetermined time for eliminating the polarization reaction of the lead battery 12 elapses after the engine is stopped, the CPU takes in the terminal voltage of the lead battery 12 measured through the voltage measuring unit 3 as an open circuit voltage OCV. The OCV is repeatedly fetched by a timer interrupt at a cycle, and at other timings, only the timer is activated and the power saving mode is entered in which no control operation is performed.

  FIG. 2 is a block diagram showing a function in which the microcomputer 10 estimates the deterioration degree SOH based on the discharge amount, the number of discharges, the temperature or the full charge capacity of the lead battery 12, and the CPU of the microcomputer 10 is a ROM. Or it implement | achieves by operate | moving based on the program previously stored in EEPROM and various data.

  The discharge amount calculation unit 101 calculates the discharge amount ΣI of the lead battery 12 per one run. The DOD calculation unit 102 calculates the discharge depth (DOD) during travel by applying the discharge amount ΣI per travel, the number n of discharges per travel, and the full charge capacity C of the lead battery 12 to the following equation (1). To do.

  In the deterioration degree increment value map 103, as shown in an example in FIG. 3, typical values of the discharge depth DOD and the deterioration degree increment value ΔSOH in a standard battery (in this embodiment, a lead battery of model 55D23 is assumed). The relationship is registered in advance for each temperature T. In the active material density correction coefficient map 104, as shown in FIG. 4, for example, the relationship between the discharge depth DOD and the active material density correction coefficient P in the lead battery is registered in advance for each positive electrode active material density.

  The deterioration degree increment correction unit 105 extracts the deterioration degree increment value ΔSOH corresponding to the DOD calculated by the DOD calculation part 102 and the temperature T measured by the temperature sensor 2 from the deterioration degree increment value map 103, and A correction coefficient P corresponding to the DOD and the known active material density of the in-vehicle lead battery 12 is extracted from the correction coefficient map 104. Then, these are applied to the following equation (2) together with the full charge capacity C0 of the standard battery to obtain the corrected deterioration degree increment value ΔSOH_r.

  The deterioration degree calculation unit 106 applies the discharge amount ΣI per driving, the corrected deterioration degree increment ΔSOH_r and the deterioration degree SOH_M (previous) before driving to the following equation (3), and the in-vehicle lead battery 12 Calculate the degree of degradation SOH_M (this time) after traveling the vehicle reflecting the active material density.

  According to the present embodiment, when calculating the deterioration degree of the lead battery using the discharge amount and the deterioration degree increment per unit discharge amount, the density of the positive electrode active material of the vehicle battery can be reflected in the deterioration degree increment. It becomes possible to calculate the deterioration degree of the above with higher accuracy.

  Further, according to the present embodiment, in calculating the deterioration degree of the lead battery using the discharge amount and the deterioration degree increment per unit discharge amount, the deterioration degree increment is used as a function of the discharge depth DOD and the temperature during vehicle travel. In addition, since the positive electrode active material density of the in-vehicle lead battery is reflected in the discharge depth DOD, the deterioration degree of the in-vehicle lead battery can be accurately calculated regardless of the positive electrode active material density.

  Furthermore, according to the present embodiment, a map for obtaining the deterioration degree increment from the discharge depth DOD and the temperature (degradation degree increment value map) is created only for the standard battery, and other sizes having different positive electrode active material densities from this standard battery, For in-vehicle batteries with a capacity, the correction factor obtained from the discharge depth DOD and the positive electrode active material density was used to correct the increment of deterioration in the standard battery. Eliminates the need to design a map.

  DESCRIPTION OF SYMBOLS 1 ... Battery state detection system, 2 ... Temperature sensor, 3 ... Voltage measuring part, 4 ... Current sensor, 5 ... IGN, 6 ... Auxiliary machine, 7 ... Generator, 8 ... Engine, 9 ... Cell motor for engine starting, 10 ... Microcomputer, 12 ... lead battery, 101 ... discharge amount calculation unit, 102 ... DOD calculation unit, 103 ... deterioration degree increment value map, 104 ... active material density correction coefficient map, 105 ... deterioration degree increment value correction part, 106 ... deterioration degree Calculation part

Claims (5)

In the battery state detection system for obtaining the degree of deterioration of the in-vehicle battery based on the amount of discharge during vehicle travel and the degree of deterioration increment per unit discharge amount,
Means for obtaining an increase in deterioration level when the vehicle is running assuming that the in-vehicle battery is a standard battery;
Means for correcting the deterioration degree increment based on the positive electrode active material density specific to the in-vehicle battery;
A battery state detection system comprising: a means for obtaining a deterioration degree of an in-vehicle battery based on a deterioration degree increment value corrected by the correcting means . Means for determining the depth of discharge of the in-vehicle battery when traveling;
A deterioration degree increment value map storing the relationship between the discharge depth of the standard battery and the deterioration degree increment value for each temperature;
The battery state detection system according to claim 1, wherein the means for obtaining the deterioration degree increment value obtains the deterioration degree increment value by applying the temperature of the in-vehicle battery and the depth of discharge to the deterioration degree increment value map. . An active material density correction coefficient map storing the relationship between the depth of discharge and the active material density correction coefficient for each positive electrode active material density;
The means for correcting the deterioration degree increment value applies an active material density correction coefficient map to the active material density correction coefficient map by applying the positive electrode active material density of the vehicle-mounted battery and the discharge depth to the active material density correction coefficient map. The battery state detection system according to claim 2, wherein the deterioration degree increment value is corrected based on a full charge capacity of the battery and a full charge capacity of the on-vehicle battery.   The means for determining the degree of deterioration of the in-vehicle battery determines the degree of deterioration after traveling by subtracting the product of the corrected deterioration degree increment value and the discharge amount from the degree of deterioration before traveling. 4. The battery state detection system according to any one of 3.   A vehicle characterized by detecting a state of an in-vehicle battery using the battery state detection system according to any one of claims 1 to 4.