JP2004072927A - Controlling device of motor-operated vehicle - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To accurately diagnose the deteriorating degree of a battery. <P>SOLUTION: A control device of a motor-operated vehicle includes the battery, and a motor receiving a power from the battery for driving the vehicle and regeneratively generating to supply a power to the battery. The control device judges a plurality of I/O patterns in which at least one of an I/O power or an I/O time of the battery is different (S1). When the I/O in response to the judged specific I/O pattern (a) is finished, current Ia, a voltage Va and SOC (state of change) of the battery at its ending time are detected (S5, S6), an internal resistance value Ra is calculated based on these detected values (S7), an internal resistance deterioration coefficient Ka is obtained based on this Ra (S9), and the deteriorating degree of the battery is diagnosed based on this Ka (S10). <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a control device for an electric vehicle including a motor for driving a vehicle (including a motor generator) and a battery (including a power supply, a battery, a capacitor, and the like), and particularly to a technique for diagnosing the degree of deterioration of the battery.
[0002]
[Prior art]
As is well known, an electric vehicle that uses a motor as a vehicle propulsion source, such as an electric vehicle or a hybrid vehicle, is equipped with a battery that exchanges power with the motor. Techniques for diagnosing such a degree of battery deterioration have been conventionally proposed.
[0003]
For example, Japanese Patent Application Laid-Open No. 2000-125415 discloses that an open-circuit voltage and an internal resistance are obtained based on a current and a voltage of a battery, a maximum output (power) is obtained from these values and a minimum guaranteed voltage, and this value and an initial reference value are obtained. A technique is disclosed in which a deterioration rate is obtained from the ratio of the above, and the degree of deterioration of the battery is diagnosed based on the deterioration rate.
[0004]
Japanese Patent Application Laid-Open No. 2000-270408 has a special diagnostic mode different from a normal vehicle driving state. In this diagnostic mode, charging / discharging is performed for diagnosis, and during charging / discharging, the current in several storage amounts is measured. And a voltage are sequentially stored, an internal resistance for each charged amount is obtained based on the data, and a diagnosis of deterioration is made based on a comparison between the internal resistance and initial data.
[0005]
Japanese Unexamined Patent Publication No. 8-336202 discloses that current and voltage during normal running are sampled, and these sampled values are subjected to linear regression calculation to obtain an internal resistance. A technique for diagnosing is disclosed.
[0006]
[Problems to be solved by the invention]
The input / output pattern such as the input / output power and input / output time of the battery changes according to the vehicle driving state, and the internal resistance also changes according to the input / output pattern. Therefore, when the internal resistance is obtained without considering the input / output pattern of the battery as in the above-mentioned Japanese Patent Application Laid-Open No. 2000-125415, an accurate internal resistance cannot be obtained, and the deterioration There is a possibility that the diagnostic accuracy may be reduced.
[0007]
In the case of performing a special diagnosis mode as in JP-A-2000-270408, the time required for the deterioration diagnosis is long, and the deterioration of the battery during normal operation cannot be immediately fed back (reflected). In addition, input / output restrictions (fail-safe) based on deterioration diagnosis cannot be quickly performed.
[0008]
Japanese Patent Application Laid-Open No. 8-336202 discloses a method of diagnosing the degree of deterioration during normal operation and issuing a warning, but does not describe the restriction of input / output (fail-safe) at the time of deterioration. For this reason, in the case of a slight deterioration that does not cause a warning, the same input / output control as in a new product is performed, and a desired input / output may not be obtained, or overcharging or overdischarging may be caused.
[0009]
[Means for Solving the Problems]
The present invention has been made in view of such a problem. A control device according to the present invention, such as an electric vehicle or a hybrid vehicle, includes a battery, and a motor that receives power supplied from the battery to drive the vehicle and performs regenerative power generation to supply power to the battery. Applied to electric vehicles. And determining means for determining a plurality of input / output patterns having at least one of different input / output power or input / output time of the battery, and diagnosing means for diagnosing the degree of deterioration of the battery for each input / output pattern. Features.
[0010]
【The invention's effect】
According to the present invention, since a plurality of input / output patterns are determined and the degree of deterioration is diagnosed for each input / output pattern, an accurate deterioration diagnosis according to the input / output patterns can be performed.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram showing a control device for an electric vehicle according to one embodiment of the present invention. In the figure, a double line indicates a power transmission path of a power train, a thick line indicates a power line of a high-current system (for example, a 42 V system), and a thin line indicates a signal line of a control system.
[0012]
This electric vehicle is a hybrid vehicle that uses both an engine 1 and a motor 2 as a vehicle propulsion source. The motor 2 is directly connected to an output shaft of the engine 1, and an automatic transmission 3, a torque converter (not shown), and the like are provided in a power train connecting the motor 2 and an axle. The automatic transmission 3 is, for example, a stepped transmission using a well-known planetary gear mechanism, or a continuously variable transmission of a toroidal type or a belt type.
[0013]
The motor 2 is connected to a high-power (for example, 42 V) battery 4 that transmits and receives power via an inverter (not shown), and is a three-phase AC type motor generator capable of both powering operation and regenerative (power generation) operation. When the engine is started, a power running operation is performed by the power supplied from the battery 4 to rotate the engine, and during braking or regeneration, regenerative power generation is performed to supply power to the battery 4 and charge the battery 4.
[0014]
A high-power circuit connecting the battery 4 and the motor 2 is provided with a main relay 5 that switches between ON and OFF, and a voltage sensor 6 and a current sensor 7 that detect the voltage and current of the battery 4. In addition, to the high-power circuit, high-power auxiliary equipment such as the electric power steering 8 is connected, and a low-power (for example, 14 V) battery or auxiliary equipment is connected via the DC / DC converter 9. (Not shown) is connected.
[0015]
A control device (microcomputer system) including a CPU, a ROM, a RAM, etc., for storing and executing various control processes, calculates and detects an engine control unit 11, a motor controller 12, and a charged amount (SOC) of the battery 4. A battery controller 13 that controls the operation of the entire vehicle is provided. The vehicle controller 14 outputs a command signal to the engine control unit 11 and the battery controller 13 based on the vehicle operating state detected and calculated by the various sensors and the like. In response to the command signal, the engine control unit 11 performs engine control such as fuel injection control and ignition timing control, and the motor controller 12 controls the torque and the number of revolutions of the motor 2.
[0016]
FIG. 2 is a flowchart illustrating a control flow according to the present embodiment. This program is executed every predetermined time, for example, every 10 ms during normal running.
[0017]
In S (step) 1, it is determined whether the input / output request of the power of the battery 4 corresponds to any of a plurality of preset input / output patterns based on the vehicle driving state and the vehicle request obtained from various sensors. Determine (determination means). In other words, it is determined whether the input / output mode of the battery corresponds to any of a plurality of different vehicle operating conditions. If there is no corresponding input / output pattern (or vehicle driving condition), this program is terminated, and if there is a corresponding pattern, the process from S2 onward described later is executed for the input / output pattern.
[0018]
The plurality of input / output patterns are selected in advance so that at least one of input / output power to the battery and input / output time is different. As an example, in this embodiment, the input / output pattern is, for example, an immediate start pattern a in which the engine is automatically restarted in a short time from an idle stop state in which the engine is automatically stopped at a traffic light or the like. A start waiting pattern b for automatically restarting the engine after elapse, an assist pattern c for providing a motor driving force in addition to the engine output as in rapid acceleration, a power generation pattern d for driving the motor by the engine to generate power, The vehicle driving energy is classified into five patterns, that is, a regenerative pattern e for regenerating the vehicle running energy by a motor during braking or the like.
[0019]
In S2, a subroutine for calculating input / output possible power shown in FIG. 3 described below is executed. At S3, the actual battery power is input / output according to the specific input / output pattern determined at S1. In other words, before actually performing input / output according to a specific input / output pattern, an input / output possible power calculation routine to be described later is executed, and input / output is restricted as necessary.
[0020]
For example, about 8 KW × 0.2 s (second) output in the immediate start pattern a, about 8 KW × 1.5 s output in the start waiting pattern b, about 10 KW × 5 s output in the assist pattern c, and about 10 KW in the power generation pattern d The input of × 30 s and the input of about 10 KW × 5 s in the regenerative pattern e are performed. In the start waiting pattern b, since the intake negative pressure is larger (closer to the atmospheric pressure) than in the immediate start pattern a, the input / output time is set relatively long in order to suppress overshoot of the engine. Note that the input / output power (KW) and the input / output time (s) may slightly fluctuate depending on the vehicle driving state.
[0021]
Hereinafter, the processing content after S4 will be described using the immediate start pattern a as an example. If it is determined in S4 that the input / output has been completed, the process proceeds to S5, and the current value Ia and the voltage value Va immediately after the end of the input / output are detected and stored as sampling values. These current values and voltage values are individually sampled for each pattern (Ia, Ib, Ic, Id, Ie, Va, Vb, Vc, Vd, Ve).
[0022]
In S6, the open circuit voltage Ea is obtained from the current (immediately after the end of the input / output) SOC with reference to the SOC-open circuit voltage setting map as shown in FIG. The relationship between the SOC and the open circuit voltage is determined by the type of the battery and the like. Basically, as shown in FIG. 6, the open circuit voltage increases as the SOC increases.
[0023]
In S7, the internal resistance value Ra for the specific input / output pattern determined in S1, from the relational expression (V = E-IR) obtained in S5 and S6 and the relational expression (V = E-IR), here, the immediate start pattern a is calculated. Compute (see FIG. 7). The latest internal resistance value thus obtained is stored and updated in a backup memory or the like for each pattern (Ra, Rb, Rc, Rd, Re), and the input / output power available in S13 of the routine of FIG. Used when asking for
[0024]
In S8, based on the internal resistance value Ra, Ra (min) is updated to the minimum value of the internal resistance stored in the backup memory or the like. Specifically, the minimum value is updated to Ra only when the latest internal resistance value Ra obtained in S7 is lower than the stored minimum value Ra (min). Normally, the internal resistance increases with the elapse of use time, so that the internal resistance when the battery is new is basically the minimum value. Therefore, instead of the process of S8, the internal resistance at the time of new product or battery replacement may be fixed as the minimum value Ra (min).
[0025]
In S9, the internal resistance deterioration coefficient Ka = Ra / Ra (min) is determined based on the internal resistance value Ra and the corresponding specific input / output pattern, here, the minimum value Ra (min) for the immediate starting pattern a. Calculate.
[0026]
In S10, the degree of deterioration of the battery is diagnosed based on the internal resistance deterioration coefficient Ka, the degree of deterioration (information) is stored, and a warning display such as turning on a warning light or issuing a warning sound as necessary is displayed. I do. Specifically, when the internal resistance deterioration coefficient Ka exceeds a predetermined threshold value, it is diagnosed that the battery is deteriorated, and a warning is displayed. The display of the warning may be performed only under the operating conditions corresponding to the input / output pattern a, or may be performed under all the operating conditions.
[0027]
Further, in accordance with the degree of deterioration, the function of the vehicle corresponding to the input / output pattern is restricted in use, that is, fail-safe. For example, in the case of the immediate start pattern a, the start electric power is limited, the idle stop is prohibited, or the motor start is stopped and the starter is started. In the case of the start waiting pattern b, the start waiting is prohibited and the operation is switched to the immediate start. In the case of the assist pattern c, the assist output by the motor 2 is limited (or the assist output is increased). In the case of the power generation pattern d, the power generated by the motor 2 is limited (or the input is increased). In the case of the regenerative pattern e, the regenerative power of the motor 2 is limited (or the input is increased).
[0028]
FIG. 3 shows an input / output available power calculation subroutine executed in S2 of FIG. Here, the instant starting pattern (a) will be described as an example.
[0029]
In S11, as in S6, the open-circuit voltage Epa for input / output power calculation is obtained based on the current SOC. This Epa and Ea of S6 become the same value if the SOC value is the same.
[0030]
In S12, the minimum guarantee voltage Vmin in the specific input / output pattern (here, the immediate start pattern) a is read. The minimum guaranteed voltage depends on the performance of the battery when the voltage drops, and tends to decrease as the power output time becomes shorter. The minimum guaranteed voltage may be a fixed value set in advance for each input / output pattern, or may be searched from a map or a table based on input / output power and input / output time.
[0031]
In S13, the maximum current value Imaxa is obtained from the internal resistance value Ra stored in S7 and the open circuit voltage Epa obtained in S11 and a well-known relational expression (V = E-IR). Based on the voltage Vmin, the input / output available power Pa = Vmin × Imaxa in the specific pattern a is obtained. The internal resistance value Ra used in S13 was stored in S7 at the time of executing the previous deterioration diagnosis on the input / output pattern a. That is, as shown in FIG. 8, Epa obtained from the current SOC, the internal resistance value Ra obtained in S7 at the time of executing the previous deterioration diagnosis routines S5 to S10, and the minimum value determined according to the input / output pattern. The input / output available power Pa is calculated based on the guaranteed voltage Vmin. As shown in FIG. 9, since the internal resistance has a substantially flat characteristic until the end of discharge when the SOC becomes equal to or less than a predetermined value (for example, 20%), Pa is simply obtained as shown in FIG. You can do it.
[0032]
In S14, the restriction on input / output in S3 in FIG. 2 is performed, that is, fail-safe is performed according to the input / output available power Pa, the subroutine ends, the process returns to the main routine in FIG. For example, if the input / output available power Pa of the immediate start pattern is lower than the required output of 8 KW, the output value in S3 is limited. If the limit is large, accurate deterioration diagnosis cannot be performed, so that the deterioration diagnosis after S5 is preferably stopped.
[0033]
S2 to S10 (including S11 to S14 of the subroutine) described above are performed for each input / output pattern determined in S1, and the internal resistance deterioration coefficients Ka, Kb, Kc, Kd, Ke, and input / output are enabled for each pattern. The powers Pa, Pb, Pc, Pd, and Pe are determined. Then, for each input / output pattern, the degree of deterioration is diagnosed based on the internal resistance deterioration coefficient, the warning light is turned on and deterioration information is recorded as necessary, and the serviceability is improved. The function of the vehicle corresponding to is restricted.
[0034]
FIG. 4 shows the relationship between the input / output time and the internal resistance. Even with the same input / output power, if the input / output time changes, the internal resistance also changes. Specifically, the internal resistance tends to increase as the input / output time increases. FIG. 5 shows the relationship between input / output power and internal resistance. Even in the same input / output time, when the input / output power changes, the internal resistance also changes. Specifically, the resistance tends to increase as the input / output power increases.
[0035]
In the present embodiment, the deterioration degree of the battery is diagnosed for each of a plurality of input / output patterns having different input / output powers and input / output times of the battery 4, so that the battery 4 may be affected by the internal resistance that changes according to the input / output patterns. The degree of deterioration can be accurately diagnosed without any problem. In addition, input / output restrictions and warnings according to the degree of deterioration of the battery can be accurately performed for each input / output pattern, so that the maximum capacity of the battery can be used without causing overcharging or overdischarging of the battery. It becomes possible.
[0036]
Immediately after the end of input / output according to a specific input / output pattern (timing at which the determination in S4 is affirmed), the I, V, and SOC are detected, and the internal resistance is determined based on these I, V, and SOC. The value and its deterioration coefficient are obtained, and the degree of deterioration is diagnosed based on the internal resistance deterioration coefficient. As described above, since the degree of deterioration is diagnosed immediately after the execution of the input / output, the diagnosis time can be shortened, and the result of the diagnosis can be promptly fed back to the warning / restriction. The capacity of a memory for storing a sampling value such as SOC is also reduced.
[0037]
Further, the internal resistance value calculated for diagnosing the degree of deterioration is stored for each input / output pattern (S7), and immediately before performing input / output according to the specific input / output pattern, Input / output possible power is calculated using an internal resistance value stored for a specific input / output pattern (S13), and based on this input / output possible power, input / output performed immediately after is limited / changed. (S14). As described above, since the internal resistance value obtained for each input / output pattern (and the vehicle operating conditions corresponding to the input / output pattern) is used, the input / output possible power can be obtained with high accuracy. Input / output can be quickly limited based on the possible power, and the performance of the battery can be utilized to the maximum without causing overcharge and overdischarge. Specifically, there is no possibility that input / output cannot be performed because the input / output power is too large, or that the original performance of the battery cannot be exhibited because the input / output power is too small.
[0038]
As described above, the present invention has been described based on the specific embodiments. However, the present invention is not limited to the embodiments and includes various modifications and changes without departing from the gist thereof. . For example, the present invention may be applied to an electric vehicle using only a motor as a vehicle propulsion source.
[Brief description of the drawings]
FIG. 1 is a schematic configuration diagram showing a control device for an electric vehicle according to an embodiment of the present invention.
FIG. 2 is a flowchart showing a control flow according to the embodiment.
FIG. 3 is a subroutine of the flowchart of FIG. 2;
FIG. 4 is a characteristic diagram showing a relationship between an input / output time of a battery and an internal resistance.
FIG. 5 is a characteristic diagram showing a relationship between input / output power of a battery and internal resistance.
FIG. 6 is a characteristic diagram showing the relationship between the SOC of the battery and the open circuit voltage.
FIG. 7 is a characteristic diagram showing how to determine an internal resistance value.
FIG. 8 is a characteristic diagram showing how to determine input / output power.
FIG. 9 is a characteristic diagram showing a relationship between the SOC of the battery and the internal resistance.
[Explanation of symbols]
1: Engine 2: Motor 4: Battery

Claims (7)

In a control device for an electric vehicle, including a battery and a motor that receives power supplied from the battery to drive the vehicle, and performs regenerative power generation to supply power to the battery.
Determining means for determining a plurality of input / output patterns having at least one of different input / output power or input / output time of a battery;
Diagnostic means for diagnosing the degree of battery deterioration for each input / output pattern;
A control device for an electric vehicle, comprising: The control apparatus for an electric vehicle according to claim 1, wherein a use restriction or a warning is displayed for a function of the vehicle corresponding to the input / output pattern diagnosed as having a high degree of battery deterioration by the diagnosis means. . The diagnostic means,
Immediately after the end of input / output according to the specific input / output pattern determined by the determination means, means for detecting a charged amount of battery, current, and voltage;
Means for calculating an internal resistance value of the battery based on the detected values;
Means for calculating an internal resistance deterioration coefficient based on the minimum value and the internal resistance value set in advance corresponding to the specific input / output pattern,
Means for diagnosing the degree of battery deterioration based on the internal resistance deterioration coefficient;
The control device for an electric vehicle according to claim 1 or 2, further comprising: Means for storing the internal resistance value of the battery calculated by the diagnostic means for each input / output pattern;
Means for calculating the input / output available power for the specific input / output pattern based on the internal resistance value before performing input / output of the battery when the specific input / output pattern is determined by the determination means;
Means for restricting input / output of at least the specific input / output pattern based on the input / output available power,
The control device for an electric vehicle according to any one of claims 1 to 3, further comprising: The control device for an electric vehicle according to any one of claims 1 to 4, wherein the motor is a motor generator that performs regenerative power generation at least during deceleration. The control device for an electric vehicle according to any one of claims 1 to 5, wherein the electric vehicle is a hybrid vehicle that uses the motor and the engine together as a vehicle propulsion source. In a control device for an electric vehicle, including a battery and a motor that receives power supplied from the battery to drive the vehicle, and performs regenerative power generation to supply power to the battery.
Determining means for determining a plurality of vehicle operating conditions having different battery input / output configurations;
Diagnostic means for diagnosing the degree of battery deterioration for each vehicle operating condition;
A diagnostic device for a vehicle, comprising:

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