JP6414460B2 - Battery deterioration state determination device and deterioration state determination method - Google Patents

Description

  The present invention relates to a first battery, a second battery, a power converter that converts a DC voltage output from the first battery into a predetermined voltage, and outputs the first battery, the second battery, and the The present invention relates to a battery deterioration state determination device and a deterioration state determination method applied to a power supply system including a converter device electrically connected to each of the power conversion devices.

  As this type of determination device, as can be seen in Patent Document 1 below, a device that determines the deterioration state of an auxiliary battery in a charging mode in which charging is performed from an auxiliary battery to a high voltage battery via a bidirectional converter is known. It has been. Specifically, in this determination apparatus, first, in the charging mode, the output characteristic of the auxiliary battery is calculated from each of the output current and the output voltage of the auxiliary battery, and the calculated output characteristic is corrected based on the temperature of the auxiliary battery. . If the corrected output characteristic is below the threshold level, a warning signal is output because the auxiliary battery has deteriorated.

JP 2006-333661 A

  By the way, the output characteristic of the auxiliary battery varies depending on the charging rate (SOC) of the auxiliary battery in addition to the temperature of the auxiliary battery. For this reason, in the determination apparatus described in Patent Document 1 that corrects the output characteristics based on the temperature of the auxiliary battery, the threshold level becomes an inappropriate value depending on the SOC, and the deterioration state of the auxiliary battery is There is a concern that the determination accuracy may be lowered.

  It is a main object of the present invention to provide a deterioration state determination device and a deterioration state determination method that can improve the determination accuracy of a deterioration state of a battery.

  Hereinafter, means for solving the above-described problems and the operation and effects thereof will be described.

  The present invention provides a first battery (10), a second battery (60), a power converter (20, 30) for converting a direct current voltage output from the first battery into a predetermined voltage, and outputting the predetermined voltage. A battery, a converter device (50, 51) electrically connected to each of the second battery and the power converter, an electric load (61) operating with the second battery as a power supply source, A power supply system comprising a voltage detection means (71) for detecting a voltage between terminals, a current detection means (71) for detecting a current flowing through the second battery, and a temperature detection means (71) for detecting the temperature of the second battery. And operating means for operating the converter device to supply power from the second battery to at least one of the first battery and the power converter. The internal resistance of the second battery based on the detected value of the voltage detecting means and the detected value of the current detecting means during a period in which power is supplied from the second battery by the operation of the converter device by the operating means. Based on the internal resistance estimating means for estimating the charging rate of the second battery, the charging rate estimating means for estimating the charging rate of the second battery, the charging rate estimated by the charging rate estimating means, and the detected value of the temperature detecting means, Resistance correction means for correcting the internal resistance estimated by the internal resistance estimation means, and determination means for determining a deterioration state of the second battery based on the internal resistance corrected by the resistance correction means. It is characterized by that.

  In the said invention, the 2nd battery is made into the determination target of a degradation state. Specifically, first, based on the detection value of the voltage detection means and the detection value of the current detection means during the period in which power is supplied from the second battery to at least one of the first battery and the power converter by the internal resistance estimation means. Then, the internal resistance of the second battery is estimated. The reason why the internal resistance is estimated is that there is a correlation between the internal resistance and the deterioration state of the second battery. Specifically, when the degree of deterioration of the second battery is large, the internal resistance is larger than when the degree of deterioration is small. Here, the internal resistance changes not only with the temperature of the second battery but also with the charging rate (SOC) of the second battery. Specifically, when the SOC is low, the internal resistance is larger than when the SOC is high. For this reason, there is a concern that the internal resistance estimated by the internal resistance estimating means cannot determine whether the SOC is simply low and the internal resistance is high or whether the degree of deterioration is actually large. In particular, when it is determined that the second battery is deteriorated even though the SOC is simply insufficient and the SOC is low, there is a concern that the maintenance cost of the power supply system may increase due to unnecessary replacement of the second battery. .

  Therefore, in the above invention, the internal resistance is corrected based on the charging rate estimated by the charging rate estimating means in addition to the detection value of the temperature detecting means. Then, the deterioration state of the second battery is determined based on the corrected internal resistance. For this reason, the deterioration determination accuracy of the second battery can be improved.

The lineblock diagram of the power supply system concerning a 1st embodiment. The flowchart which shows the procedure of a deterioration determination process. The figure for demonstrating a pseudo-open state. The flowchart which shows the procedure of a battery state determination process. The figure which shows the regression line which defines the relationship between detection current and detection voltage. The figure which shows the relationship between detected temperature and a temperature correction coefficient. The figure which shows the relationship between SOC and an open circuit voltage. The figure which shows the relationship between SOC and a SOC correction coefficient. The flowchart which shows the procedure of a 1st determination process. The flowchart which shows the procedure of a 2nd determination process. The time chart which shows an example of a deterioration determination process. The flowchart which shows the procedure of the 1st determination process concerning 2nd Embodiment. The flowchart which shows the procedure of the degradation determination process concerning 3rd Embodiment.

(First embodiment)
Hereinafter, a first embodiment in which a battery deterioration state determination apparatus according to the present invention is applied to an in-vehicle power supply system will be described with reference to the drawings. In this embodiment, a hybrid vehicle having a rotating electric machine (motor generator) and an engine as main engines is assumed as a vehicle on which the power supply system is mounted.

  As shown in FIG. 1, the on-vehicle power supply system includes a high voltage battery 10, a traction inverter 20, an air conditioning inverter circuit 30, a first motor generator 40, a second motor generator 41, an air conditioning motor 42, a first DCDC converter 50, and a second DCDC. A converter 51, an auxiliary battery 60, an auxiliary load 61, and a controller 70 are provided. Here, the inter-terminal voltage (for example, several hundreds V) of the high-voltage battery 10 is set higher than the inter-terminal voltage (for example, about 12 V) of the auxiliary battery 60. As the high voltage battery 10, for example, a lithium ion storage battery or a nickel hydride storage battery can be used. In the present embodiment, a lead storage battery is used as the auxiliary battery 60. The auxiliary battery 60 includes a series connection body of a plurality (six) cells and a separator that electrically insulates each cell. Each cell is composed of a pair of electrodes immersed in an electrolytic solution, and outputs a voltage of about 2 V per cell in this embodiment.

  Incidentally, in the present embodiment, the high voltage battery 10 corresponds to a “first battery”, and the auxiliary battery 60 corresponds to a “second battery”. In the present embodiment, three-phase motor generators 40 and 41 and an air conditioning motor 42 are used. For example, permanent magnet synchronous motors can be used as the first and second motor generators 40 and 41 and the air conditioning motor 42. Further, in FIG. 1, as the auxiliary load 61, an electric power steering device, an electronically controlled brake system, a meter device, and the like are illustrated.

  The traction inverter 20 includes a boost converter circuit 21 and an inverter circuit 22. The boost converter circuit 21 is a boost chopper circuit including a first capacitor 21a, a reactor 21b, an upper arm switch Sp, a lower arm switch Sn, and a second capacitor 21c. In the present embodiment, IGBTs are used as the switches Sp and Sn. Free wheel diodes Dp and Dn are connected in antiparallel to the switches Sp and Sn. The collector of the lower arm switch Sn is connected to the emitter of the upper arm switch Sp. The connection point of each switch Sp, Sn is connected to the emitter of the lower arm switch Sn via the reactor 21b and the first capacitor 21a. A second capacitor 21c is connected in parallel to the series connection body of the switches Sp and Sn.

  The high voltage battery 10 is connected to the input side (first capacitor 21a side) of the boost converter circuit 21 via a system main relay SMR. On the other hand, an inverter circuit 22 is connected to the output side (second capacitor 21 c side) of the boost converter circuit 21. The inverter circuit 22 includes a three-phase first inverter circuit connected to the first motor generator 40 and a three-phase second inverter circuit connected to the second motor generator 41. The first and second inverter circuits have a function of converting a DC voltage output from the boost converter circuit 21 into an AC voltage and applying it to the first and second motor generators 40 and 41. The first motor generator 40 serves as a starter for applying initial rotation to a generator and a crankshaft of an in-vehicle main engine (not shown). Further, the second motor generator 41 is mechanically connected to the drive wheels 43 and plays a role of an in-vehicle main machine or the like.

  A three-phase air conditioning inverter circuit 30 is connected to the first capacitor 21 a, and an air conditioning motor 42 is connected to the air conditioning inverter circuit 30. The air conditioning motor 42 is for driving an electric compressor constituting the in-vehicle air conditioner. The air conditioning inverter circuit 30 converts the DC voltage output from the high voltage battery 10 into an AC voltage and applies it to the air conditioning motor 42.

  Of the electrical path connecting the high voltage battery 10 and the first capacitor 21a, the first DCDC converter 50 is connected to the first capacitor 21a side of the system main relay SMR, and the second DCDC converter 51 is connected to the high voltage battery 10 side. Is connected. An auxiliary battery 60 and an auxiliary load 61 are connected to the first and second DCDC converters 50 and 51. The first DCDC converter 50 electrically insulates between the high-voltage system (corresponding to the “first voltage region”) and the low-voltage system (corresponding to the “second voltage region”) and power between the high-voltage system and the low-voltage system. Is a bidirectional insulation type. In the present embodiment, the first DCDC converter 50 steps down the output voltage of the high voltage battery 10 and supplies it to at least one of the auxiliary battery 60 and the auxiliary load 61, or increases the output voltage of the auxiliary battery 60 to increase the voltage. Or supply to the system. In the present embodiment, the high voltage system includes a high voltage battery 10, a traction inverter 20, an air conditioning inverter circuit 30, a first motor generator 40, a second motor generator 41, and an air conditioning motor 42. The low voltage system includes an auxiliary battery 60 and an auxiliary load 61. The second DCDC converter 51 steps down the DC voltage output from the high voltage battery 10 and supplies it to at least one of the auxiliary battery 60 and the auxiliary load 61 while electrically insulating the high voltage system and the low voltage system.

  Incidentally, in the present embodiment, the first DCDC converter 50 and the second DCDC converter 51 constitute a “converter device”.

  The power supply system further includes a battery sensor 71 that detects a current flowing through the auxiliary battery 60, a voltage between terminals of the auxiliary battery 60, and a temperature of the auxiliary battery 60. The current, the voltage between terminals, and the temperature detected by the battery sensor 71 are input to the controller 70. In the present embodiment, the charging current of the auxiliary battery 60 is represented by a positive value, and the discharging current of the auxiliary battery 60 is represented by a negative value. Incidentally, in the present embodiment, the battery sensor 71 corresponds to “voltage, current, temperature detection means”.

  The controller 70 is mainly composed of a microcomputer including a CPU and a memory 70a (corresponding to “storage means”). The controller 70 operates the boost converter circuit 21 to boost the output voltage of the high voltage battery 10 and supply the boosted voltage to the inverter circuit 22, operates the inverter circuit 22 to drive the first and second motor generators 40, The air conditioning inverter circuit 30 is operated to drive the air conditioning motor 42. The controller 70 turns the system main relay SMR off and on so as to electrically open and close the boost converter circuit 21 and the air conditioning inverter circuit 30 and the high voltage battery 10. The controller 70 further operates the first DCDC converter 50, the second DCDC converter 51, and the auxiliary machine load 61.

  Incidentally, in the present embodiment, the boost converter circuit 21, the inverter circuit 22, the air conditioning inverter circuit 30, the system main relay SMR, the DCDC converters 50 and 51, and the auxiliary load 61 are operated by a common controller 70. However, it is good also as a structure operated by the controller set individually to each of these each apparatus.

  Next, the deterioration determination process for the auxiliary machine load 61 according to the present embodiment will be described with reference to FIG. This process is repeatedly executed by the controller 70 at a predetermined processing cycle, for example.

  In this series of processes, first, in step S10, it is determined whether or not the precharge operation is permitted when the vehicle is started. In the present embodiment, the precharge operation is to charge the first capacitor 21a and the second capacitor 21c using the auxiliary battery 60 as a power supply source by the step-up operation of the first DCDC converter 50 prior to turning on the system main relay SMR. Is the action. By the precharge operation, the inrush current is prevented from flowing through the traction inverter 20.

  When an affirmative determination is made in step S10, the process proceeds to step S11, and a precharge operation for charging the capacitors 21a and 21c by the operation of the first DCDC converter 50 is performed. In the present embodiment, the process of this step corresponds to “operation means”.

  In the subsequent step S12, a plurality of voltages between the terminals of the auxiliary battery 60 (detected voltage VA) detected by the battery sensor 71 and a current flowing through the auxiliary battery 60 (hereinafter, detected current IA) are detected during the precharge operation. Sampling. Note that the sampling period is set to 5 msec, for example.

  In a succeeding step S13, it is determined whether or not the precharge operation should be completed. If a negative determination is made in step S13, the process returns to step S11. On the other hand, if an affirmative determination is made in step S13, the process proceeds to step S14 to instruct the first DCDC converter 50 to stop the precharge operation. Thereby, the discharge current of the auxiliary battery 60 gradually decreases with time.

  In subsequent step S15, it is determined whether or not the current (charge / discharge current) flowing through auxiliary battery 60 has approached 0A. This process is a process for determining whether or not the pseudo open circuit voltage OCV of the auxiliary battery 60 is detectable. In the present embodiment, when it is determined that the detected current IA is equal to or less than 0 A and is equal to or greater than a predetermined current Ithres (for example, −1 A) that is less than 0 A, it is determined that the current flowing through the auxiliary battery 60 has approached 0 A. In the present embodiment, the predetermined current Ithres is a threshold value set in view of the difficulty of continuing the state in which the charge / discharge current of the auxiliary battery 60 is made equal to 0 for a certain period of time.

  If it is determined in step S15 that the current flowing through the auxiliary battery 60 has approached zero, the process proceeds to step S16, and the detection voltage VA is detected as the pseudo open voltage OCV.

  On the other hand, when it is determined in step S15 that the current flowing through the auxiliary battery 60 is not close to 0, that is, the detected current IA is less than the predetermined current Ithres, the process proceeds to step S17, and after the process of step S14, the pre- It is determined whether or not the charging operation is actually stopped. If it is determined in step S17 that the precharge operation is not actually stopped, the process returns to step S14. On the other hand, if it is determined in step S17 that the vehicle is actually stopped, the process proceeds to step S18, and the system main relay SMR is turned on to start the vehicle.

  In subsequent steps S19 and S20, charging is performed by stepping down the output voltage of the high-voltage battery 10 and supplying the auxiliary battery 60 by operating the second DCDC converter 51 until it is determined that the current flowing through the auxiliary battery 60 has approached zero. Perform the action. In this process, as shown in FIG. 3, the second DCDC converter 51 is operated so that the discharge current from the auxiliary battery 60 to the auxiliary load 61 is canceled by the charging current from the high voltage battery 10 to the auxiliary battery 60. It is processing. That is, although the precharge operation is actually stopped (S17: YES), the situation in which a negative determination is made in step S15 is that the auxiliary battery 60 is changed to the auxiliary load 61 in response to a request from the auxiliary load 61. This is a situation where a discharge current flows. In order to detect the pseudo open voltage OCV, it is necessary to bring the charging / discharging current of the auxiliary battery 60 close to 0. Therefore, the charging / discharging of the auxiliary battery 60 is controlled by controlling the charging current from the high voltage battery 10 to the auxiliary battery 60. The current is brought close to 0. In FIG. 3, a state in which the discharge current is canceled by the charging current is shown as a pseudo open state. In the present embodiment, the process of step S19 corresponds to “balance control means”.

  If it is determined in step S20 that the current flowing through the auxiliary battery 60 has approached zero, the process proceeds to step S16, and the detected voltage VA is detected as the pseudo open voltage OCV of the auxiliary battery 60. In the subsequent step S21, the temperature TA of the auxiliary battery 60 is detected by the battery sensor 71. In a succeeding step S22, a battery state determination process is performed.

  The battery state determination process will be described with reference to FIG.

  In step S30, based on the combination of the plurality of detection currents IA and detection voltage VA sampled in step S12, a regression line “VA =” that defines the relationship between the detection current IA and the detection voltage VA using the following equation (eq1). The regression coefficient a of “a × IA + b” is calculated (see FIG. 5).

上式（ｅｑ１）において、「Ｎ」はサンプリング数を示す。そして、ステップＳ３０において、回帰係数ａを補機バッテリ６０の内部抵抗である等価直列抵抗ＥＳＲとして推定する。なお本実施形態において、本ステップの処理が「内部抵抗推定手段」に相当する。

In the above equation (eq1), “N” indicates the number of samplings. In step S30, the regression coefficient a is estimated as an equivalent series resistance ESR that is the internal resistance of the auxiliary battery 60. In the present embodiment, the processing in this step corresponds to “internal resistance estimating means”.

  In subsequent step S31, the equivalent series resistance ESR estimated in step S30 is corrected by the temperature detected in step S21 (hereinafter, detected temperature TA). Specifically, first, as shown in FIG. 6, a temperature correction coefficient Kt (> 0) that is set lower as the detected temperature TA is higher is calculated. Here, the temperature correction coefficient Kt when the detected temperature TA becomes the reference temperature Tb (for example, 25 ° C.) is set to 1. Then, the equivalent series resistance ESR is corrected by multiplying the equivalent series resistance ESR by the calculated temperature correction coefficient Kt. This process is performed in view of the fact that the equivalent series resistance ESR decreases as the temperature of the auxiliary battery 60 increases.

  Returning to the description of FIG. 4 above, in the following step S32, the charging rate (SOC) of the auxiliary battery 60 is estimated based on the pseudo open voltage OCV detected in step S16. Here, the reason why the SOC can be estimated using the pseudo open circuit voltage OCV is because the open circuit voltage of the auxiliary battery 60 and the SOC are uniquely determined as shown in FIG. In FIG. 7, the minimum value Vmin of the open circuit voltage is, for example, 11.82 V, and the maximum value Vmax of the open circuit voltage is, for example, 12.76 V. In the present embodiment, the process of this step corresponds to “charging rate estimating means”.

  In the subsequent step S33, the equivalent series resistance “Kt × ESR” corrected in step S31 is further corrected based on the estimated SOC. Specifically, first, as shown in FIG. 8, an SOC correction coefficient Ks (> 0) that is set lower as the estimated SOC is higher is calculated. Here, the SOC correction coefficient Ks when the SOC becomes the reference value Sb is set to 1. Then, the equivalent series resistance ESR is corrected by multiplying the equivalent series resistance “ESR × Kt” by the calculated SOC correction coefficient Ks. This process is performed in view of the fact that the equivalent series resistance ESR increases as the SOC of the auxiliary battery 60 decreases. Hereinafter, the equivalent series resistance ESR corrected in step S33 is referred to as a corrected resistance. Incidentally, in the present embodiment, the processing of steps S31 and S33 corresponds to “resistance correction means”.

  In the subsequent step S34, the corrected resistance corrected in step S33 is stored in the memory 70a.

  In a succeeding step S35, it is determined whether or not the SOC estimated in the step S32 is larger than the determination threshold value SCth. This process is a process for determining whether or not the SOC is suitable for determining the deterioration state of the auxiliary battery 60. That is, for example, when the SOC decreases due to leaving the auxiliary battery 60 for a long period of time, the equivalent series resistance increases. In this case, in the first determination process described later, there is a concern that the auxiliary battery 60 is erroneously determined to be deteriorated even though it is not actually deteriorated.

  If an affirmative determination is made in step S35, the process proceeds to step S36 to perform a first determination process. Hereinafter, the first determination process will be described with reference to FIG.

  In step S60, it is determined whether or not the corrected resistance of the current processing cycle in step S33 is equal to or greater than the warning threshold value Elimit1 (corresponding to “first threshold value”). This process is a process for determining whether or not the auxiliary battery 60 has deteriorated. When an affirmative determination is made in step S60, the process proceeds to step S61, and it is determined whether or not the corrected resistance of the current processing cycle is equal to or greater than a limit threshold ESlimit2 (corresponding to a “first threshold”) that is greater than the warning threshold ESlimit1. to decide. This process is a process for determining whether or not the deterioration degree of the auxiliary battery 60 is large and the discharge current from the auxiliary battery 60 to the auxiliary load 61 should be limited.

  If a negative determination is made in step S61, the process proceeds to step S62, and the first flag F1 is set to “1”. Here, the first flag F1 indicates that the auxiliary battery 60 is deteriorated by “1”, and indicates that the auxiliary battery 60 is not deteriorated by “0”. The initial value of the first flag F1 is set to “0”.

  On the other hand, when an affirmative determination is made in step S61, the process proceeds to step S63, and the second flag F2 is set to “1”. Here, the second flag F2 indicates that the auxiliary battery 60 has deteriorated due to “1” and that the discharge current to the auxiliary load 61 should be limited. Indicates no deterioration. Note that the initial value of the second flag F2 is set to “0”.

  When the processes of steps S62 and S63 are completed, or when a negative determination is made in step S60, the process proceeds to step S64, where the corrected resistance of the current process cycle is the equivalent series resistance ESin of the new auxiliary battery 60. It is determined whether or not it is equal to or greater than a specified value α (α is an integer of 2 or more). This process is a process for determining whether or not the auxiliary battery 60 has deteriorated, as in step S60. This determination method is based on the fact that the presence or absence of deterioration can be determined based on the equivalent series resistance of a new auxiliary battery 60.

  If an affirmative determination is made in step S64, the process proceeds to step S65, and whether or not the corrected resistance of the current processing cycle is equal to or greater than the value obtained by multiplying the equivalent series resistance ESin of the new auxiliary battery 60 by the second specified value β. Determine whether. Here, the second specified value β is set to an integer larger than the first specified value α. This process is a process for determining whether or not the discharge current from the auxiliary battery 60 to the auxiliary load 61 should be limited, as in step S61.

  If a negative determination is made in step S65, the process proceeds to step S66, and the first flag F1 is set to “1”. On the other hand, if an affirmative determination is made in step S65, the process proceeds to step S67, and the second flag F2 is set to “1”.

  When the processes of steps S66 and S67 are completed or when a negative determination is made in step S64, the process proceeds to step S68 to determine whether or not the value of the second flag F2 is “1”. If an affirmative determination is made in step S68, the process proceeds to step S69 to determine that the auxiliary battery 60 has deteriorated. Then, an abnormality notification process and an auxiliary machine load restriction process are performed. The abnormality notification process is, for example, a process of notifying the control device higher than the controller 70 that the auxiliary battery 60 has deteriorated, or notifying the driver of the deterioration by using a notification means such as a warning light. And it is sufficient. Further, the auxiliary machine load limiting process, for example, by forcibly reducing the allowable upper limit value of the power consumption of the auxiliary machine load 61 or by forcibly reducing the current power consumption of the auxiliary machine load 61, What is necessary is just to set it as the process which reduces the discharge current from the auxiliary machine battery 60 to the auxiliary machine load 61. FIG.

  If a negative determination is made in step S68, the process proceeds to step S70 to determine whether or not the value of the first flag F1 is “1”. When an affirmative determination is made in step S70, the process proceeds to step S71, and it is determined that the auxiliary battery 60 has deteriorated. Then, abnormality notification processing is performed. If a negative determination is made in step S70, the process proceeds to step S72 to determine that the auxiliary battery 60 is normal.

  Returning to the description of FIG. 4 described above, if a negative determination is made in step S35, the process proceeds to step S37 to perform a second determination process. Hereinafter, the second determination process will be described with reference to FIG.

  In step S80, it is determined whether or not the SOC estimated in step S32 is less than the lower limit threshold SCmin. Lower limit threshold value SCmin is a value smaller than determination threshold value SCth, and is set to a lower limit value that can be taken by the SOC when auxiliary battery 60 is normal.

  If an affirmative determination is made in step S80, the process proceeds to step S81 to determine whether or not the corrected resistance of the current processing cycle is smaller than the corrected resistance of the previous processing cycle stored in the memory 70a. This process is a process for determining whether or not a cell short circuit abnormality of the auxiliary battery 60 has occurred. In other words, when a short circuit occurs between cells constituting auxiliary battery 60, the SOC of auxiliary battery 60 decreases to a value less than lower limit threshold SCmin. In addition, when a cell short circuit occurs, the equivalent series resistance decreases. Specifically, for example, when a one-cell short circuit occurs, the equivalent series resistance is reduced to 5/6. For this reason, when the SOC becomes lower than the lower limit threshold SCmin and the corrected resistance of the current processing cycle becomes smaller than the corrected resistance of the previous processing cycle stored in the memory 70a, a cell short circuit occurs. Judge that there is.

  The process of step S80 is a process of determining whether or not the pseudo open voltage OCV detected in step S16 is less than the minimum value of the range that the pseudo open voltage OCV can take when the auxiliary battery 60 is normal. It may be replaced. This is because the open circuit voltage of the auxiliary battery 60 and the SOC are uniquely determined. Incidentally, when a short circuit occurs between cells, specifically, for example, the open-circuit voltage of the auxiliary battery 60 is reduced to 10.5 V which is less than the minimum value Vmin.

  If an affirmative determination is made in step S81, the process proceeds to step S82, where it is determined that a cell short circuit abnormality has occurred, and an abnormality notification process is performed. In the subsequent step S83, the third flag F3 is set to “1”. Here, the third flag F3 indicates that a cell short circuit abnormality has occurred by “1”, and that a cell short circuit abnormality has not occurred by “0”. The initial value of the third flag F3 is set to “0”.

  Returning to the description of FIG. 4, in the subsequent step S38, it is determined whether or not the value of the third flag F3 is “1”. If an affirmative determination is made in step S38, or if the process in step S36 is completed, the deterioration determination process is temporarily terminated.

  On the other hand, if a negative determination is made in step S38, the process proceeds to step S39, and a recharging operation is performed in which the output voltage of the high voltage battery 10 is stepped down and supplied to the auxiliary battery 60 again by operating the second DCDC converter 51. This process is a process for increasing the SOC of the auxiliary battery 60 in order to improve the deterioration determination accuracy in view of the negative determination in step S35. In the present embodiment, it is assumed that the system main relay SMR is turned on after step S16 of FIG. 2 and before the processing of step S39. In the present embodiment, the process of this step corresponds to “recharging means”.

  In a succeeding step S40, it is determined whether or not the recharging operation is completed. If it is determined in step S40 that the process has been completed, the process proceeds to step S41. In step S <b> 41, polarization is performed by operating the second DCDC converter 51 to discharge from the auxiliary battery 60 and supply to at least one of the high voltage battery 10, the first motor generator 40, the second motor generator 41, and the air conditioning motor 42. Perform removal processing. This process is a process for removing the influence of the polarization of the auxiliary battery 60 caused by the recharging operation. That is, there is a concern that the estimated SOC may deviate from the actual SOC due to the influence of polarization. In this embodiment, the process of this step corresponds to “polarization removing means”.

  In subsequent step S42, a plurality of detected voltages VA and detected currents IA during the polarization removal process are sampled. In a succeeding step S43, it is determined whether or not the polarization removal process should be completed. If a negative determination is made in step S43, the process returns to step S41. On the other hand, when an affirmative determination is made in step S43, the process proceeds to step S44, and a process for stopping the polarization removal process in accordance with an instruction to the second DCDC converter 51 is performed.

  In a succeeding step S45, it is determined whether or not the current flowing through the auxiliary battery 60 has approached 0A. If it is determined in step S45 that the current flowing through the auxiliary battery 60 has approached 0, the process proceeds to step S46, and the detection voltage VA is detected as the pseudo open voltage OCV.

  On the other hand, when it is determined in step S45 that the current flowing through the auxiliary battery 60 has not approached 0, the process proceeds to step S47, and it is determined whether or not the polarization removal process is actually stopped. If it is determined in step S47 that it has not actually stopped, the process returns to step S44. On the other hand, if it is determined in step S47 that it is actually stopped, the second DCDC converter 51 is operated to increase the voltage until it is determined in steps S48 and S49 that the current flowing through the auxiliary battery 60 has approached zero. A charging operation for reducing the output voltage of the battery 10 and supplying it to the auxiliary battery 60 is performed. This process is a process provided for the same purpose as the process of the previous step S19.

  If it is determined in step S49 that the current flowing through the auxiliary battery 60 has approached zero, the process proceeds to step S46, and the pseudo open voltage OCV of the auxiliary battery 60 is detected. In the subsequent step S50, the temperature TA of the auxiliary battery 60 is detected by the battery sensor 71. After completion of step S50, the process returns to step S30. In step S30, the equivalent series resistance ESR is estimated again. In subsequent steps S31 to S33, the SOC is estimated again, and the equivalent series resistance ESR is corrected again. Thereafter, when it is determined that the SOC exceeds the determination threshold SCth, the deterioration determination of the auxiliary battery 60 is performed again based on the corrected resistance by the first determination process.

  Incidentally, when it is determined in step S39 that the recharging operation has been performed M times (M is an integer of 2 or more), the deterioration determination process may be stopped.

  FIG. 11 shows an example of the deterioration determination process according to the present embodiment. In FIG. 11, (a) shows changes in the voltage VL between the terminals of the first capacitor 21a, (b) and (c) show changes in the detected voltage VA and the detected current IA, and (d) and (e) The transition of the output voltage of the first and second DCDC converters 50 and 51 is shown. Here, in FIGS. 11D and 11E, the step-down means a state in which a voltage is output from the first and second DCDC converters 50 and 51 to the low-voltage system side. In FIG. 11D, boosting means a state in which a voltage is output from the first DCDC converter 50 to the high voltage system side. In the figure, the period A assumes several hundreds msec, and the period B assumes several hundreds sec.

  In the illustrated example, at time t1, a precharge operation at the time of starting the vehicle is started. Thereafter, at times t1 to t2, a plurality of detection currents IA and detection voltages VA for estimating the equivalent series resistance ESR are sampled during the precharge operation.

  Thereafter, at time t2 to t4, the pseudo open circuit voltage OCV is detected in a state where the detection current IA is close to zero. In FIG. 11, system main relay SMR is turned on at time t3.

  Thereafter, at time t4 to t5, a recharging operation is performed by operating the second DCDC converter 51, and the SOC of the auxiliary battery 60 increases. Thereafter, at time t5 to t6, polarization removal processing is performed by operating the first DCDC converter 50, and at time t6 to t7, the pseudo open voltage OCV is detected in a state where the detection current IA is close to zero. After that, when it is determined that the SOC is equal to or greater than the determination threshold SCth and the auxiliary battery 60 is normal based on the corrected resistance, the control shifts to normal control of the vehicle.

  According to the embodiment described in detail above, the following effects can be obtained.

  (1) In addition to the detected temperature TA, the presence or absence of deterioration of the auxiliary battery 60 is determined based on the equivalent series resistance ESR corrected by the SOC. For this reason, the deterioration determination accuracy of the auxiliary battery 60 can be improved.

  (2) The second DCDC converter 51 so that the charging current flowing from the high voltage battery 10 to the auxiliary battery 60 via the second DCDC converter 51 and the discharging current flowing from the auxiliary battery 60 to the auxiliary load 61 are balanced. The above charging current was controlled by the operation. Then, the detected voltage VA in the balanced state is detected as the pseudo open voltage OCV, and the SOC is estimated based on the detected pseudo open voltage OCV. The detection voltage VA when the charge / discharge current of the auxiliary battery 60 is close to 0 is a value close to the open voltage of the auxiliary battery 60. The open circuit voltage of the auxiliary battery 60 and the SOC uniquely correspond to each other. For this reason, the detected voltage VA when the charge / discharge current is close to 0 is detected as the pseudo open voltage OCV, and the charging rate of the auxiliary battery 60 is estimated based on the detected pseudo open voltage OCV. Thereby, the estimation accuracy of the SOC can be improved, and the calculation accuracy of the SOC correction coefficient Ks can be improved. Therefore, the deterioration determination accuracy based on the corrected resistance can be improved.

  Furthermore, according to the present embodiment in which the pseudo open voltage OCV is detected in a state where the discharge current and the charge current are balanced, for example, the intercept b of the regression line “VA = a × IA + b” is detected as the pseudo open voltage OCV. Compared to the configuration, an improvement in detection accuracy of the pseudo open circuit voltage OCV can be expected. That is, when the auxiliary battery 60 is discharged by operating the first DCDC converter 50, for example, during a precharge operation, the harmonic component (for example, several hundred kHz) due to the ripple current of the first DCDC converter 50 causes the auxiliary battery 60 to A voltage drop due to internal inductance can occur. In this case, there is a concern that the intercept b is apparently lowered. On the other hand, according to the present embodiment, since the actual voltage detection value in the balanced state is set to the pseudo open voltage OCV, an improvement in detection accuracy of the pseudo open voltage OCV can be expected.

  (3) The regression coefficient a of the regression line was calculated based on the plurality of detected voltages VA and the plurality of detected currents IA during the precharge operation, and the calculated regression coefficient a was estimated as the equivalent series resistance ESR. For this reason, the equivalent series resistance ESR can be estimated appropriately. In addition, during the precharge operation, the voltage between the terminals of the auxiliary battery 60 also decreases as the discharge current of the auxiliary battery 60 increases. Therefore, the detection current IA and the detection voltage VA for calculating the regression coefficient a are set. It can also be acquired appropriately.

  (4) When it is determined that the resistance after correction of the current processing cycle is equal to or greater than the warning threshold value Elimit1, it is determined that the auxiliary battery 60 has deteriorated, and abnormality notification processing is performed. In addition, when it is determined that the corrected resistance of the current processing cycle is equal to or greater than the limit threshold ESlimit2, the auxiliary machine load limit process is performed in addition to the abnormality notification process. For this reason, it is possible to avoid an increase in the discharge current of the auxiliary battery 60 in a state where the deterioration of the auxiliary battery 60 has progressed, and as a result, safety of the vehicle can be ensured.

  (5) When it is determined that the corrected resistance of the current processing cycle is greater than or equal to α times the equivalent series resistance of the new auxiliary battery 60, it is determined that the auxiliary battery 60 has deteriorated. Further, when it is determined that the corrected resistance of the current processing cycle is equal to or greater than β times the equivalent series resistance of the new auxiliary battery 60, auxiliary load limiting processing is performed in addition to the abnormality notification processing. . For this reason, the safety of the vehicle can be ensured.

  (6) When the SOC is less than the lower limit threshold SCmin and it is determined that the corrected resistance of the current processing cycle is lower than the corrected resistance of the previous processing cycle, the cell short circuit abnormality of the auxiliary battery 60 It was determined that this occurred. According to such a configuration, it is possible to determine whether the abnormality of the auxiliary battery 60 is large or small.

  (7) The recharging operation was performed on the condition that the SOC was determined to be equal to or less than the determination threshold SCth. And the polarization removal process was performed after the recharge operation. For this reason, the influence of polarization can be removed and the fall of the estimation precision of SOC can be avoided. As a result, the calculation accuracy of the SOC correction coefficient Ks can be improved, and consequently the deterioration determination accuracy based on the corrected resistance can be improved.

  Furthermore, the detection voltage VA and the detection current IA for estimating the equivalent series resistance ESR can be sampled after the start of the vehicle, for example, even when the vehicle is parked or stopped, by using the polarization removal process. In addition, wasteful power consumption can be reduced by using the high voltage battery 10 as the discharge destination of the auxiliary battery 60 in the polarization removal process.

(Second Embodiment)
Hereinafter, the second embodiment will be described with reference to the drawings with a focus on differences from the first embodiment. In the present embodiment, the second determination processing method is partially changed.

  FIG. 12 shows the procedure of the second determination process according to the present embodiment. This process is repeatedly executed by the controller 70 at a predetermined processing cycle, for example. In FIG. 12, the same processes as those shown in FIG. 9 are given the same reference numerals for the sake of convenience.

  In this series of processing, in step S64a, the corrected resistance of the current processing cycle is the third specified value γ times (γ is an integer of 2 or more) after the correction in the previous processing cycle stored in the memory 70a. It is determined whether or not the value is greater than or equal to the value. This process is a process provided for the same purpose as step S64 of FIG. Depending on the specifications of the auxiliary battery 60, the equivalent series resistance suddenly increases when the accumulated usage time exceeds a certain level. Here, according to the determination method of this step, it can be determined that the auxiliary battery 60 has deteriorated from this rapid change.

  If an affirmative determination is made in step S64a, the process proceeds to step S65a, and the corrected resistance of the current processing cycle is equal to or greater than the fourth specified value δ times the corrected resistance in the previous processing cycle stored in the memory 70a. Judge whether there is. The fourth specified value δ is set to an integer larger than the third specified value γ. This process is a process provided for the same purpose as step S65 of FIG. If a negative determination is made in step S65a, the process proceeds to step S66. On the other hand, if a positive determination is made in step S65a, the process proceeds to step S67.

  According to the present embodiment described above, the same effect as the first embodiment can be obtained.

(Third embodiment)
Hereinafter, the third embodiment will be described with reference to the drawings with a focus on differences from the first embodiment. In the present embodiment, after the vehicle is started, for example, the deterioration determination process for the auxiliary battery 60 is performed even while the vehicle is running.

  FIG. 13 shows a procedure of deterioration determination processing according to the present embodiment. This process is repeatedly executed by the controller 70 at a predetermined processing cycle, for example. In FIG. 13, the same processes as those shown in FIG. 2 are given the same reference numerals for the sake of convenience.

  In this series of processes, first, in step S10a, it is determined whether or not there is at least one assist request among the first motor generator 40, the second motor generator 41, and the air conditioning motor. Here, the assist request is for driving at least one of the first motor generator 40, the second motor generator 41, and the air conditioning motor 42 using the auxiliary battery 60 in addition to the high voltage battery 10 as a power supply source. It is. The assist request is made under a situation where the output power of the high voltage battery 10 is limited, for example. Here, the assist request of the first motor generator 40 is made, for example, when the traveling power of the vehicle is increased. The assist request of the second motor generator 41 is made, for example, when initial rotation is applied to the crankshaft of the engine (cranking is performed). The assist request for the air conditioning motor 42 is made, for example, when the cooling capacity is increased.

  If an affirmative determination is made in step S10a, the process proceeds to step S11a, and at least one of the first motor generator 40, the second motor generator 41, and the air conditioning motor 42 from the auxiliary battery 60 by the boosting operation of the first DCDC converter 50. Assist operation to supply power to one of them. In subsequent steps S12 and S13a, the detection voltage VA and the detection current IA are sampled a plurality of times until it is determined that the assist operation is completed.

  In the subsequent step S14a, the first DCDC converter 50 is instructed to stop the assist operation. Thereby, the discharge current of the auxiliary battery 60 gradually decreases with time. Thereafter, in step S17a, it is determined whether or not the assist operation is actually stopped. If a positive determination is made in step S17a, the process proceeds to step S19.

  According to the present embodiment described above, for example, whether or not the auxiliary battery 60 is deteriorated can be determined even while the vehicle is traveling.

(Other embodiments)
Each of the above embodiments may be modified as follows.

  When there is a concern that the required power of the auxiliary load 61 increases rapidly during the estimation of the equivalent series resistance ESR and the power supply system is down, the auxiliary device supplied to the high voltage system by the input voltage protection control of the first DCDC converter 50 The power of the battery 60 may be limited, or estimation of the equivalent series resistance ESR may be stopped.

  In each of the above embodiments, the second DCDC converter 51 is not essential. Here, when removing the second DCDC converter 51 from the power supply system, if the charging operation or the recharging operation is performed by the operation of the first DCDC converter 50 in the processing of Step S19 of FIG. 2 and Steps S39 and S48 of FIG. Good. Further, the power supply system may include three or more DCDC converters. In this case, at least one bidirectional DCDC converter is sufficient.

  In FIG. 4 of the first embodiment, the polarization removal process does not have to be performed when accuracy reduction due to the influence of polarization can be tolerated. In this case, for example, the equivalent series resistance ESR may be estimated based on the sampling values of the detection voltage VA and the detection current IA during the recharging operation. Then, the SOC is estimated again after the recharging operation, and the equivalent series resistance ESR used for the deterioration determination may be corrected based on the estimated SOC and the detected temperature TA.

  In each of the above embodiments, the intercept b of the regression line “VA = a × IA + b” that defines the relationship between the detected voltage VA and the detected current IA may be calculated, and the calculated intercept b may be used as the pseudo open voltage OCV.

  In each of the above embodiments, instead of the corrected resistance in the previous processing cycle stored in the memory 70a, the corrected resistance in the previous processing cycle stored in the memory 70a, etc., the processing before the previous processing cycle You may determine the deterioration state of the auxiliary battery 60 using the resistance after correction | amendment in a period.

  The traction inverter 20 may not include the boost converter circuit 21. Further, the power supply system is not limited to that mounted on the vehicle.

  DESCRIPTION OF SYMBOLS 10 ... High voltage battery, 20 ... Traction inverter, 30 ... Air conditioning inverter circuit, 50 ... 1st DCDC converter, 60 ... Auxiliary battery, 61 ... Auxiliary load, 71 ... Battery sensor.

Claims (10)

A first battery (10), a second battery (60), a power converter (20, 30) that converts a DC voltage output from the first battery into a predetermined voltage and outputs the voltage, the first battery, the first battery Converter device (50, 51) electrically connected to each of the two batteries and the power converter, an electric load (61) that operates using the second battery as a power supply source, and a voltage across the terminals of the second battery. Applied to a power supply system comprising voltage detecting means (71) for detecting, current detecting means (71) for detecting the current flowing through the second battery, and temperature detecting means (71) for detecting the temperature of the second battery,
Operating means for operating the converter device to supply power from the second battery to at least one of the first battery and the power converter;
Based on the detection value of the voltage detection means and the detection value of the current detection means during a period in which power is supplied from the second battery by the operation of the converter device by the operation means, the internal resistance of the second battery is reduced. An internal resistance estimating means for estimating;
The voltage detection in a state in which a total value of a charging current flowing from the first battery to the second battery via the converter device and a discharging current flowing from the second battery to the electric load is close to 0 Means for detecting the detected value of the means as a pseudo open voltage;
Charging rate estimating means for estimating a charging rate of the second battery;
Resistance correcting means for correcting the internal resistance estimated by the internal resistance estimating means based on the charging rate estimated by the charging rate estimating means and a detection value of the temperature detecting means;
When it is determined that the charging rate estimated by the charging rate estimation unit is equal to or less than a determination threshold, the detected pseudo open voltage can be an open voltage of the second battery when the second battery is normal. Based on the fact that the current internal resistance, which is less than the lower limit of the range and is corrected by the resistance correction means, is lower than the previous internal resistance, a short circuit abnormality has occurred in the second battery. Determination means for determining the effect,
When it is determined by the determination means that the short circuit abnormality has not occurred, a charging means for charging the second battery using the first battery as a power supply source by operating the converter device;
After the charging by the charging means, in order to remove the influence of the polarization of the second battery due to the charging, at least one of the first battery and the power converter is moved from the second battery to the power converter by operating the converter device. A polarization removing means for discharging,
The internal resistance estimating means calculates the internal resistance of the second battery based on the detected value of the voltage detecting means and the detected value of the current detecting means during a period when the second battery is discharged by the polarization removing means. Estimate again,
The charge rate estimating means estimates the charge rate again after the discharge from the second battery by the polarization removing means is completed,
The resistance correction unit corrects the internal resistance estimated again based on the charge rate estimated again and the detection value of the temperature detection unit,
The determination means, the resistance on the basis of the internal resistance that is again corrected by the correction means, battery deterioration state determining device comprising a Turkey to determine the deterioration state of the second battery. The internal resistance estimation unit is configured to detect a detection value of the voltage detection unit based on a plurality of detection values of the voltage detection unit and a plurality of detection values of the current detection unit during a period in which power is supplied from the second battery. and the current regression coefficients of the regression line defining the relationship between the detection value of the detection means is calculated, the calculated the estimated regression coefficients as the internal resistance according to claim 1 Symbol placement of battery deterioration state determining device. The determination means, the case where the internal resistance is corrected again by the resistance correction means determines that equal to or greater than the first threshold value, the second battery is judged according to claim 1 or 2, wherein that has deteriorated battery Degradation state determination device. When the determination unit determines that the internal resistance corrected again by the resistance correction unit is equal to or greater than a second threshold value that is greater than the first threshold value, the power supplied from the second battery to the electric load is determined. The battery deterioration state determination device according to claim 3 to be limited. Storage means (70a) for storing the internal resistance corrected again by the resistance correction means;
The determination means is based on a difference between the current internal resistance corrected again by the resistance correction means and the past internal resistance stored in the storage means or the internal resistance of the new second battery. The battery deterioration state determination apparatus according to any one of claims 1 to 4 , wherein it is determined that the second battery has deteriorated. The power converter is
A step-up chopper circuit (21) having capacitors (21a, 21c) and stepping up and outputting a DC voltage output from the first battery;
An inverter circuit (22) for converting the output voltage of the step-up chopper circuit into an alternating voltage and outputting the alternating voltage,
The power supply system includes a rotating electrical machine (40, 41) driven by an AC voltage output from the inverter circuit,
The operation means operates the converter device to precharge the capacitor constituting the power converter from the second battery,
The internal resistance estimating means, on the basis of the detected value of the detection value and the current detecting means of the voltage detection means in the period which has been precharged, any one of claims 1 to 5 for estimating the internal resistance The battery deterioration state determination device according to claim 1. Said operating means, said second order to supply electric power from the battery to the first battery, the battery deterioration determination device according to any one of claims 1 to 6 for operating the converter device. The power supply system includes a rotating electrical machine (40 to 42) driven by an AC voltage output from the power converter (22, 30),
The battery operating state according to any one of claims 1 to 7 , wherein the operating means operates the converter device so as to supply electric power from the second battery to the rotating electrical machine via the power conversion device. Judgment device. The power supply system is mounted on a vehicle,
The output voltage of the first battery is set higher than the output voltage of the second battery,
The first battery and the power converter are provided in a first voltage region of the power supply system,
Said second battery and said electrical load, said a voltage region of the power system, any one of claim 1 to 8, from the first voltage region provided in the electrically insulated second voltage regions The battery deterioration state determination device according to claim 1. A first battery (10), a second battery (60), a power converter (20, 30) that converts a DC voltage output from the first battery into a predetermined voltage and outputs the voltage, the first battery, the first battery Converter device (50, 51) electrically connected to each of the two batteries and the power converter, an electric load (61) that operates using the second battery as a power supply source, and a voltage across the terminals of the second battery. Applied to a power supply system comprising voltage detecting means (71) for detecting, current detecting means (71) for detecting the current flowing through the second battery, and temperature detecting means (71) for detecting the temperature of the second battery,
The voltage detection means in a period in which power is supplied from the second battery by operating the converter device for supplying power from the second battery to at least one of the first battery and the power converter. Estimating an internal resistance of the second battery based on a detection value and a detection value of the current detection means;
The voltage detection in a state in which a total value of a charging current flowing from the first battery to the second battery via the converter device and a discharging current flowing from the second battery to the electric load is close to 0 Detecting the detected value of the means as a pseudo open voltage;
Estimating a charging rate of the second battery;
Correcting the estimated internal resistance based on the estimated charging rate and the detected value of the temperature detecting means;
When it is determined that the estimated charging rate is equal to or less than a determination threshold, the detected pseudo open voltage is less than a lower limit value of a range that the open voltage of the second battery can take when the second battery is normal. And, based on the fact that the corrected current internal resistance is lower than the past internal resistance, determining that a short circuit abnormality has occurred in the second battery;
When it is determined that the short circuit abnormality has not occurred, the operation of the converter device charges the second battery using the first battery as a power supply source; and
After the charging of the second battery, in order to remove the influence of the polarization of the second battery due to the charging, the second battery is placed in at least one of the first battery and the power conversion device by operating the converter device. Discharging from
In order to eliminate the influence of the polarization, the internal resistance of the second battery is estimated again based on the detection value of the voltage detection means and the detection value of the current detection means during the period when the second battery is discharged. Steps,
Re-estimating the charge rate after completion of discharge from the second battery to remove the effect of the polarization;
Re-correcting the re-estimated internal resistance based on the re-estimated charge rate and the detected value of the temperature detection means;
And determining a deterioration state of the second battery based on the internal resistance corrected again .

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