JP2015201941A - Vehicle battery system and control method of vehicle battery system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To determine one or more batteries which are discharged so as to improve efficiency of charge after discharge.SOLUTION: For each of a plurality of batteries, the SOC thereof is acquired, current consumption of an accessory is acquired, and a time until the start of charging to the plurality of batteries by a generator is estimated. On the basis of the current consumption of the accessory and the time until the start of charging, a total discharge amount to be discharged from the plurality of batteries until the start of charging is predicted. On the basis of the acquired SOC, a map indicating a relation between the SOC for the plurality of batteries and charging acceptability and the predicted total discharge amount, one or more batteries to execute discharging until the start of charging are determined from among the plurality of batteries in such a manner that the total charging acceptability of the plurality of batteries becomes equal to or greater than a predetermined value, and discharging is executed from the determined one or more batteries.

Description

  The present invention relates to a vehicle battery system having a plurality of batteries and a method for controlling the vehicle battery system.

  Patent Document 1 discloses a vehicle power supply system that includes a plurality of batteries and a generator that generates electrical energy used to charge the plurality of batteries. Each battery is based on a detected value of a current flowing through each battery. And calculating means for calculating the charging acceptability of each of the batteries, and selecting a battery to be preferentially charged from among the plurality of batteries based on the calculated charging acceptability, and preferentially selecting the selected battery. A vehicle power supply system including a selective charging means for charging is described.

JP 2004-222473 A

  In Patent Document 1, a battery having high charge acceptability is preferentially charged at the start of charging. However, in the case where there are a plurality of batteries, it has not been sufficiently studied about which battery should be discharged in order to improve the efficiency of charging after discharging.

  SUMMARY An advantage of some aspects of the invention is to solve at least a part of the problems described above, and the invention can be implemented as the following forms.

  (1) According to one aspect of the present invention, a vehicle battery system mounted on a vehicle is provided. This vehicle battery system includes a plurality of batteries having different amounts of change in charge acceptance with respect to the amount of discharge, an auxiliary device, a generator, and a map showing a relationship between each SOC and charge acceptance for each of the plurality of batteries. A map storage unit for storing, an SOC acquisition unit for acquiring each SOC for each of the plurality of batteries, a current consumption acquisition unit for acquiring current consumption of the auxiliary device, and charging of the plurality of batteries by the generator The charging start time estimation unit that estimates the time until the start, the consumption current acquired by the consumption current acquisition unit, and the time until the charging start estimated by the charging start time estimation unit. The total discharge amount prediction unit that predicts the total discharge amount discharged from the plurality of batteries, the SOC acquired by the SOC acquisition unit, and the map storage unit that stores the And starting the charging from the plurality of batteries based on the total discharge amount predicted by the total discharge amount predicting unit so that the total charge acceptance of the plurality of batteries is equal to or greater than a predetermined value. A battery determination unit that determines one or more batteries to be discharged in the meantime, and a battery discharge control unit that performs discharge from the one or more batteries determined by the battery determination unit. According to the vehicle battery system of this aspect, the control unit determines one or more batteries from the plurality of batteries so that the total charge acceptance after the discharge of the total discharge amount becomes a predetermined value or more, and the battery discharge Since the control unit causes the determined battery to discharge, the efficiency of charging after discharging can be improved, and fuel consumption can be suppressed.

  (2) In the vehicle battery system according to the above aspect, the battery determination unit may include at least one battery that causes discharge to be performed from among the plurality of batteries so that total charge acceptance of the plurality of batteries is maximized. You may decide. According to the vehicle battery system of this aspect, the battery determination unit determines one or more batteries from the plurality of batteries so that the sum of the charge acceptability is maximized after the total discharge amount is discharged, and the battery discharge control is performed. Since the unit causes the determined battery to discharge, the efficiency of charging after discharging can be improved, and fuel consumption can be suppressed.

(3) In the vehicle battery system of the above aspect, the number of the batteries is two;
The battery determination unit (a) first charge acceptability after discharging the total discharge amount only from the first battery, and (b) after discharging the total discharge amount only from the second battery. Comparing the second charge acceptability with (c) the third charge acceptability after discharging the total discharge amount from both the first battery and the second battery; and (d) the first charge acceptability. When the charge acceptability of the second battery is the highest, only the first battery is determined as a battery that performs discharge. (E) When the second charge acceptability is the highest, only the second battery is used as the battery that performs the discharge. (F) When the third charge acceptability is the highest, both the first battery and the second battery may be determined as batteries to be discharged. According to the vehicle battery system of this aspect, the battery determination unit determines one or more batteries from the two batteries so that the charge acceptability is maximized after the total discharge amount is discharged, and the battery discharge control unit Since discharging is performed from the determined battery, the efficiency of charging after discharging can be improved, and fuel consumption can be suppressed.
(4) In the vehicle battery system according to the above aspect, when the battery discharge control unit does not discharge at least one of the plurality of batteries, the OCV of the battery that does not perform the discharge is acquired, and the SOC and OCV The SOC value of the battery that does not perform the discharge is determined using a predetermined relationship, and the charge acceptability of the battery that does not perform the discharge is measured by charging the battery that does not perform the discharge, and the discharge is performed. You may further provide the map update part which updates the said map of the battery which is not performed. According to the vehicle battery system of this aspect, the OCV is measured when the battery is not discharged, and the map indicating the relationship between the SOC and the charge acceptability is updated. Therefore, the estimation accuracy of the charge acceptability can be improved. I can do it.

  (5) According to one form of this invention, the control method of a vehicle battery system provided with the some battery from which the variation | change_quantity of the charge acceptance property with respect to discharge amount differs is provided. In this control method, each SOC is obtained for each of the plurality of batteries, the consumption current of the auxiliary machine is obtained, the time until the start of charging of the plurality of batteries by the generator is estimated, and the consumption of the auxiliary machine is obtained. Based on the current and the time until the start of charging, the total amount of discharge discharged from the plurality of batteries until the start of charging is predicted, and the obtained SOC, and the SOC and charging for the plurality of batteries Based on the map indicating the relationship with acceptability and the predicted total discharge amount, charging is performed from among the plurality of batteries such that the sum of charge acceptability of the plurality of batteries is equal to or greater than a predetermined value. One or more batteries to be discharged before the start are determined, and discharging is performed from the determined one or more batteries. According to the control method of this embodiment, after the total discharge amount is discharged, one or more batteries are determined from the plurality of batteries so that the total charge acceptability is equal to or greater than a predetermined value, and the discharge from the determined batteries is performed. Since it performs, the efficiency of the charge after discharge can be improved and fuel consumption can be suppressed.

  (6) In the control method for a vehicle battery system according to the above aspect, one or more batteries may be determined from the plurality of batteries so that the total charge acceptability of the plurality of batteries is maximized. According to the control method of this embodiment, one or more batteries are determined from the plurality of batteries so that the total charge acceptance is the largest after the total discharge amount is discharged, and the discharge is executed from the determined batteries. Therefore, the efficiency of charging after discharging can be improved, and fuel consumption can be suppressed.

(7) In the vehicle battery system control method of the above aspect, the number of the batteries is two, and (a) first charge acceptance after discharging the total discharge amount from only the first battery; (B) a second charge acceptability after discharging the total discharge amount from only the second battery; and (c) after discharging the total discharge amount from both the first battery and the second battery. And (d) when the first charge acceptance is the highest, the battery is discharged using only the first battery, and (e) the second charge acceptance is the highest. When it is large, the battery may be discharged using only the second battery. (F) When the third charge acceptability is the highest, the battery may be discharged using both the first battery and the second battery. According to the control method of this embodiment, one or more batteries are determined from the two batteries so that the charge acceptance is maximized after the total discharge amount is discharged, and the discharge is executed from the determined batteries. The efficiency of charging after discharging can be improved, and fuel consumption can be suppressed.
(8) In the control method for a vehicle battery system according to the above aspect, when at least one of the plurality of batteries is not discharged, an OCV of the battery that is not discharged is obtained, and the SOC and OCV are The SOC value of the battery that is not discharged is determined using a predetermined relationship, the battery that is not discharged is charged, charge acceptance is measured, and the map of the battery that is not discharged is determined. It may be updated. According to the control method of this embodiment, the OCV is measured when the battery is not discharged, and the map indicating the relationship between the SOC and the charge acceptability is updated, so that the estimation accuracy can be improved.

  Note that the present invention can be realized in various modes. For example, in addition to the vehicle battery system, the present invention can be realized in the form of a vehicle battery system control method, a battery charging method, and the like.

It is explanatory drawing which shows the vehicle battery system of 1st Embodiment. It is explanatory drawing which shows the structure of a control part. It is a map which shows the relationship between SOC of 1st battery stored in a map memory | storage part, and 2nd battery, and charge acceptance. It is an operation | movement flowchart of the vehicle battery system in 1st Embodiment. It is an operation | movement flowchart of the vehicle battery system in 1st Embodiment. It is a time chart of the vehicle battery system in 1st Embodiment. It is explanatory drawing which shows the relationship between the discharge from a battery, and charge acceptance. It is an operation | movement flowchart of the vehicle battery system in 2nd Embodiment. It is a graph which shows the relationship between SOC and OCV. It is explanatory drawing which shows the update of the map which shows the relationship between SOC and charge acceptance.

  FIG. 1 is an explanatory diagram illustrating a vehicle battery system 10 according to the first embodiment. The vehicle battery system 10 is a system mounted on a vehicle, and includes a control unit 100, a first battery 110, a second battery 120, an alternator 130, a starter 140, an auxiliary machine 150, and a first switch 160. , A second switch 165, a first ammeter 170, and a second ammeter 175. In the present embodiment, the first battery 110 and the second battery 120 are both secondary batteries. The first battery 110 and the second battery 120 only need to have a different relationship between the SOC and the charge acceptability. In the first embodiment, a lead storage battery is used as the first battery 110 and a lithium ion battery is used as the second battery 120. ing. The second battery 120 may be a nickel metal hydride battery. Alternator 130 is a generator that generates power using the driving force of an engine (not shown).

  The alternator 130 may regenerate kinetic energy of the vehicle as electric energy when the vehicle on which the vehicle battery system 10 is mounted is decelerated. The starter 140 is a starting device that starts the engine. The auxiliary machine 150 includes various electric devices necessary for driving the vehicle. For example, auxiliary machine 150 includes headlamps, fog lamps, cornering signal lamps, corner lamps, oil pumps, meters, electronic throttle throttle and brake ABS systems, air conditioners such as air conditioners, audio, car Navigation, power window, etc. are included.

  The first switch 160 is a switch that switches connection / disconnection of the first battery 110. When the first switch 160 is on, the first battery 110 is charged with power or discharged from the first battery 110. The second switch 165 is a switch that switches connection / disconnection of the second battery 120. When the second switch 165 is on, power is charged in the second battery 120 or power is discharged from the second battery 120. If the power generation amount of the alternator 130 is larger than the power consumption of the auxiliary machine 150, the first battery 110 or the second battery 120 is charged. If the power generation amount of the alternator 130 is smaller than the power consumption of the auxiliary machine 150, Electric power is discharged from the first battery 110 or the second battery 120. The first ammeter 170 measures the charging current or discharging current of the first battery 110. The second ammeter 175 measures the charging current or discharging current of the second battery 120.

  FIG. 2 is an explanatory diagram illustrating the configuration of the control unit 100. The control unit 100 includes a map storage unit 101, an SOC acquisition unit 102, a current consumption acquisition unit 103, a charge start time estimation unit 104, a total discharge amount prediction unit 105, a battery determination unit 106, and a battery discharge control unit. 107 and a map update unit 108. Map storage unit 101 stores a map indicating the relationship between SOC and charge acceptance.

  FIG. 3 is a map showing the relationship between the SOC and charge acceptance of the first battery 110 and the second battery 120 stored in the map storage unit 101. A map indicating the relationship between the SOC and the charge acceptability is created in advance for each battery. The SOC is an abbreviation for State of Charge, and is a value indicating how much electricity is charged in the battery, assuming that the capacity when the battery is fully charged is 100%.

  2 acquires the SOCs of the first battery 110 and the second battery 120. The SOC acquisition unit 102 calculates the SOC value of the first battery 110 as follows. The first battery is fully charged and then fully discharged. The capacity when the first battery is fully charged (SOC 100%) is measured in advance from the discharge amount at that time. Then, by integrating the subsequent discharge amount from the first battery 110 and the charge amount to the first battery 110, the current amount of electricity charged in the first battery 110 is acquired. The SOC can be calculated by dividing the amount of electricity currently charged in the first battery 110 by the capacity of the battery when fully charged (SOC 100%). The SOC acquisition unit 102 calculates the SOC for the second battery 120 in the same manner. The consumption current acquisition unit 103 acquires the consumption current consumed by the auxiliary machine 150. The charging start time estimation unit 104 estimates the time until charging of the first battery 110 and the second battery 120 from the current time. Based on the consumption current acquired by the consumption current acquisition unit 103 and the time until the charging start estimated by the charging start time estimation unit 104, the total discharge amount prediction unit 105 and the first battery 110 and the second The total discharge amount discharged from the battery 120 is predicted.

  Based on the charge acceptability of the first battery 110 and the second battery 120, the battery determination unit 106 (a) discharges only from the first battery 110, (b) discharges only from the second battery 120, ( c) Decide whether to discharge from both the first battery 110 and the second battery 120. The charge acceptability is also referred to as “charge recovery property” and is an index indicating the ease of charging during battery charging. The charge acceptability is obtained, for example, by passing a current through the battery and integrating the current value at that time over a predetermined time. The acceptability estimating unit 104 estimates the charge acceptability of the first battery 110 and the second battery 120 after discharging using the map 101 before discharging from the first battery 110 and the second battery 120. The battery determination unit 106 determines one or more batteries to be discharged during the period from the current time to the start of charging so that the total charge acceptability is maximized after discharging.

  The relationship between SOC and charge acceptance varies depending on the type of battery. As shown in FIG. 3, the first battery 110 has a large charge acceptance in the high SOC region even if the SOC is reduced, but the charge acceptance is large in the low SOC region when the SOC is reduced. Become. On the other hand, the second battery 120 has a higher charge acceptability when the SOC is reduced in the high SOC region, but the charge acceptability is not so large in the low SOC region even if the SOC is reduced. Thus, the charge acceptability varies depending on the type of battery and the SOC, and the first battery 110 and the second battery 120 differ in the amount of change in charge acceptability with respect to the discharge amount.

  When the same voltage is applied to a plurality of batteries, a battery with high charge acceptance at the start of charging is charged faster than a battery with low charge acceptance. That is, when the battery is charged with the same electric capacity, the battery with higher charge acceptance at the start of charging is charged faster than the battery with lower charge acceptance. When the battery is charged using the alternator 130, the power generation time of the alternator 130 is short and less fuel is consumed. Therefore, it is preferable to discharge from a battery with high charge acceptability after discharge. However, as can be seen from FIG. 3, which charge acceptability of the first battery 110 and the second battery 120 changes depending on the SOC value. The battery discharge control unit 107 performs discharge using the battery determined by the battery determination unit 106. The map update unit 108 updates the map stored in the map storage unit. The update of the map will be described in the second embodiment.

  4 and 5 are operation flowcharts of the vehicle battery system in the first embodiment. In step S <b> 100, control unit 100 calculates the SOCs of first battery 110 and second battery 120. When the first battery 110 is attached to the vehicle, the control unit 100 fully discharges the first battery 110 and then completely discharges the first battery 110 at the time of full charge (SOC 100%) from the discharge amount at that time. The capacity is measured in advance. The current charge amount of the first battery 110 is calculated by integrating the subsequent discharge amount from the first battery 110 and the charge amount to the first battery 110. The SOC of the first battery 110 can be calculated by dividing by the capacity of the first battery 110 when fully charged (SOC 100%). The same applies to the SOC of the second battery 120.

  In step S110, the control unit 100 starts fuel consumption control or charge control, and starts discharging from the battery. The fuel consumption control means that the control unit 100 controls the fuel consumption by limiting the power generation by the alternator 130. If fuel consumption control is performed, the amount of power generated by the alternator 130 is reduced, so that the battery is discharged. Charging control means charging the battery using regenerative energy when the vehicle is decelerated. If the SOC of the battery becomes too large, the battery tends to deteriorate. Therefore, when charge control is performed, the battery is discharged from the battery in advance so that the SOC of the battery does not become excessive. Note that which battery (only the first battery 110, only the second battery 120, both the first battery 110 and the second battery 120) is to be discharged is determined by the subsequent processing result. Note that the battery is charged after discharging.

  In step S120, the control unit 100 predicts or estimates the total discharge amount from the first battery 110 and the second battery 120 between the current time and the start of charging before the start of charging. The consumption current acquisition unit of the control unit 100 acquires the current consumption current of the auxiliary machine 150. The charging start time estimation unit 104 estimates the time from the present to the start of charging. The total discharge amount prediction unit 105 predicts or estimates the total discharge amount from the first battery 110 and the second battery 120 until the start of charging using the consumption current of the auxiliary machine 150 and the time until the start of charging. Can do.

  In steps S130, S140, and S150, a plurality of different sets selected from the first battery 110 and the second battery 120 (first discharge battery set: only the first battery 110, second discharge battery set: second Charge acceptability is estimated for each discharging battery set when discharging is performed using the discharging battery set of only the battery 120, the third discharging battery set (both the first battery 110 and the second battery 120).

  In step S130, the first charge acceptability of the first discharging battery set is calculated. First, in step S132, the control unit 100 estimates the future SOC of the first battery 110 when the SOC decreases due to discharging. The future SOC of the first battery 110 is the SOC of the first battery 110 after the discharge when it is assumed that the total discharge amount is all discharged from the first battery 110. The control unit 100 discharges only from the first battery 110 for a predetermined time (for example, 10 seconds), measures the discharge amount at that time, and uses the discharge amount and the SOC of the first battery 110 before the discharge to generate the first battery. Estimate 110 future SOCs.

  In step S134, control unit 100 estimates the future charge acceptability of first battery 110 using the future SOC of first battery 110 and a map (for example, FIG. 3) showing the relationship between the SOC and the charge acceptability. To do. In step S135, control unit 100 acquires the current charge acceptability of second battery 120 using the SOC of second battery 120 obtained in step S100 and a map indicating the relationship between the SOC and the charge acceptability. . In step S136, the control unit 100 adds the future charge acceptability of the first battery 110 and the current charge acceptability of the second battery 120, and first charge acceptability Ca1 of the first discharging battery set. Is calculated.

  In step S140, the control unit 100 calculates the second charge acceptability Ca2 of the second discharge battery set in the same procedure as in step S130. In step S142, control unit 100 estimates the future SOC of second battery 120. In step S144, control unit 100 estimates the future charge acceptability of second battery 120 using the future SOC of second battery 120 and a map indicating the relationship between the SOC and the charge acceptability. In step S145, control unit 100 acquires the current charge acceptability of first battery 110 using a map indicating the relationship between SOC and charge acceptability. In step S146, the control unit 100 adds the future charge acceptability of the second battery 120 and the current charge acceptability of the first battery 110, and the second charge acceptability Ca2 of the second discharge battery set. Is calculated.

  In step S150, the control unit 100 calculates the third charge acceptability Ca3 of the third discharge battery set in the same procedure as in step S130. In step S152, control unit 100 estimates the future SOC of first battery 110 and second battery 120. In step S154, control unit 100 estimates future charge acceptability of first battery 110 and second battery 120 using a map indicating the relationship between SOC and charge acceptability. In step S156, the control unit 100 adds the future charge acceptability of the first battery 110 and the future charge acceptability of the second battery 120 to obtain the third charge acceptability Ca3 of the third discharge battery set. Is calculated.

  In the description of the flowchart, steps S130, S140, and S150 are described in the order. However, steps S130, S140, and S150 may be performed in any order and may be performed simultaneously.

  In step S160, the control unit 100 determines whether the first charge acceptability Ca1 is maximum. When the first charge acceptability Ca1 is maximum, the control unit 100 shifts the process to step S165 and discharges using the first discharge battery set (only the first battery 110). In step S170, the control unit 100 determines whether the second charge acceptability Ca2 is maximum. When the second charge acceptability Ca2 is maximum, the control unit 100 shifts the process to step S175 and discharges using the second discharge battery set (only the second battery 120). In Steps S160 and S170, if both are No, the third charge acceptability Ca3 is the maximum. In this case, the control unit 100 discharges using the third discharge battery set (both the first battery 110 and the second battery 120). As described above, the control unit 100 selects which battery set is used to discharge the total discharge amount. Specifically, when the first discharge battery set is selected, the total discharge amount is discharged from the first battery 110. When the second discharge battery set is selected, the total discharge amount is discharged from the second battery 120. When the third discharge battery set is selected, the total discharge amount is discharged from both the first battery 110 and the second battery 120.

  FIG. 6 is a time chart of the vehicle battery system in the first embodiment. When the fuel consumption control or the charge control in step S110 of FIG. 4 is started at time t1, the discharge control of the first battery 110 and the second battery 120 is turned on. Since the first battery 110 and the second battery 120 are discharged, the SOC is lowered. The period from time t1 to t2 is a period corresponding to step S132 in FIG. The controller 100 calculates the first charge acceptability Ca1 to the third charge acceptability Ca3 between t1 and t2, and determines the battery that performs the discharge. In the present embodiment, it is assumed that the control unit 100 determines to discharge from the second battery 120. At time t2, control unit 100 turns off discharge control of first battery 110 and maintains discharge control of second battery 120 on. As a result, the SOC of the first battery 110 stops decreasing, but the SOC of the second battery 120 continues to decrease. Note that, at time t2, the control unit 100 has determined to discharge from the second battery 120, but this determination is determined as follows.

  FIG. 7 is an explanatory diagram showing the relationship between discharge from the battery and charge acceptance. FIG. 7A shows a case where only the first battery 110 is discharged. The charge acceptability of the first battery 110 after discharging is Ca11. In addition, the charge acceptance of the 2nd battery 120 does not change with Ca20. Therefore, the first charge acceptability Ca1 is Ca11 + Ca20.

  FIG. 7B shows a case where only the second battery 120 is discharged. The charge acceptability of the second battery 120 after discharging is Ca22. In addition, the charge acceptance of the 1st battery 110 does not change with Ca10. Therefore, the second charge acceptability Ca2 is Ca12 + Ca20.

  FIG. 7C shows a case where both the first battery 110 and the second battery 120 are discharged. The charge acceptability of the first battery 110 after discharge is Ca13, and the charge acceptability of the second battery 120 is Ca23. Therefore, the third charge acceptability Ca3 is Ca13 + Ca23.

  When Ca1, Ca2, and Ca3 are compared, the second acceptability Ca2 is the largest (large), the large one acceptability Ca1 is the smallest (small), and the third acceptability Ca3 is the middle (medium). Therefore, the control unit 100 determines to discharge only the second battery 120.

  As described above, according to the present embodiment, the control unit 100 estimates the future charge acceptability, determines the discharge battery set to be discharged so that the sum of the future rechargeable battery insertion capacity becomes the largest, Discharge from the battery in the battery set. As a result, the amount of fuel consumed during subsequent charging of the battery can be reduced.

  In the above description, the second battery 120 is discharged as a result. However, depending on the SOC value, the first battery 110 is discharged, and the first battery 110 and the second battery 120 are discharged. It may become.

In addition, although this embodiment demonstrated the vehicle battery system which has two batteries (1st battery 110, 2nd battery 120), the number of batteries should just be two or more (two or more). For example, when the number of batteries is three (the first battery 110, the second battery 120, and the third battery 230), the control unit 100 calculates the following seven charge acceptability Cb1 to Cb7.
(A) First charge acceptability Cb1 when the total discharge amount is discharged only from the first battery 110 (future rechargeability of the first battery 110 and current rechargeability of the second battery 120) And the total rechargeable battery capacity of the third battery 230)
(B) Second charge acceptance Cb2 when the total discharge amount is discharged only from the second battery 120 (the current chargeability of the first battery 110 and the future chargeability of the second battery 120) And the total rechargeable battery capacity of the third battery 230)
(C) Third charge acceptance Cb3 when the total discharge amount is discharged only from the third battery 230 (the current chargeability of the first battery 110 and the current chargeability of the second battery 120) And the total rechargeability of the third battery 230 in the future)
(D) Fourth charge acceptance Cb4 when the total discharge amount is discharged from the two batteries of the first battery 110 and the second battery 120 (the future battery chargeability of the first battery 110 and the second battery 120 future rechargeability and total rechargeability of the third battery 230)
(E) A fifth charge acceptability Cb5 when the total discharge amount is discharged from the two batteries of the first battery 110 and the third battery 230 (future rechargeability of the first battery 110 and the second battery 120 current rechargeability and total rechargeability of the third battery 230 in the future)
(F) Sixth charge acceptability Cb6 (the current battery chargeability of the first battery 110 and the second battery when the total discharge amount is discharged from the two batteries of the second battery 120 and the third battery 230. 120 future rechargeable battery capacity and third battery 230 future rechargeable battery capacity)
(G) Seventh charge acceptance Cb7 when the total discharge amount is discharged from the three batteries of the first battery 110, the second battery 120, and the third battery 230 (future rechargeable battery of the first battery 110) The sum of the battery packability, the future battery packability of the second battery 120, and the future battery packability of the third battery 230)

  The control unit 100 acquires the one with the highest charge acceptance among the seven charge acceptances Cb1 to Cb7, and causes the discharge from one or more batteries to be performed so that the charge acceptance after discharge becomes the largest. Specifically, for example, when the fourth charge acceptance Cb4 is the largest, the control unit 100 performs discharge from the two batteries of the first battery 110 and the second battery 120, and from the third battery 230, Performs discharge control so as not to perform discharge.

  In the said form, the charge acceptance property after discharge of the total discharge amount is calculated, and it discharges from one or more batteries so that the charge acceptance property after discharge of a total discharge amount may become the largest. However, as long as the total charge acceptance after discharge of the total discharge amount is equal to or greater than a predetermined value, the charge acceptance after discharge of the total discharge amount may not be the largest. For example, if both the first charge acceptability Ca1 and the third charge acceptability Ca3 are equal to or greater than a predetermined value, the control unit 100 (a) discharges only from the first battery 110, (b) first Either discharging from both the first battery 110 and the second battery 120 may be selected.

  FIG. 8 is an operation flowchart of the vehicle battery system according to the second embodiment. When executing the discharge from only the first battery 110 in step S165, the control unit 100 measures the OCV (Open Circuit Voltage) of the second battery 120 in step S200. Since no current flows through the second battery 120, the control unit 100 can measure the OCV by measuring the voltage between the two output terminals of the second battery 120. In step S210, the SOC acquisition unit 102 of the control unit 100 corrects the SOC value of the second battery 120 using the OCV. As described above, the control unit 100 can calculate the SOC by integrating the discharge amount from the second battery 120 and the charge amount to the second battery 120. However, as the number of times of charging / discharging the second battery increases, the error increases. Therefore, the control unit 100 may correct the SOC value of the second battery 120 using the OCV.

  FIG. 9 is a graph showing the relationship between SOC and OCV. In the SOC usage range, the SOC and the OCV are in a substantially proportional relationship, and the control unit 100 can acquire the SOC if the OCV can be measured. Therefore, when the SOC acquisition unit 102 of the control unit 100 does not discharge from one battery, the SOCV of the battery can be measured and the SOC value can be corrected.

  In step S220, the SOC acquisition unit 102 of the control unit 100 similarly measures the OCV of the first battery 110, and corrects the SOC value of the first battery 110 using the OCV in step S230. The operation flowchart of FIG. 8 is executed following the operation flowchart of FIG. In the operation flowchart of FIG. 4, since any one of steps S165, S175, and S180 is executed, the flow of steps S165, S200, and S210 and the flow of steps S175, S220, and S230 are also performed in FIG. Is executed based on the result of FIG. In FIG. 4, when step S180 is executed, the operation flowchart of FIG. 8 is not executed.

  When the vehicle decelerates in step S240, control unit 100 shifts the process to step S250. In step S250, the kinetic energy of the vehicle is regenerated by the alternator 130, and the first battery 110 and the second battery 120 are charged. The battery determination unit 106 of the control unit 100 acquires charge acceptability from the amount of charge charged in the first battery 110 and the second battery 120 for a predetermined time. In step S260, the battery determination unit 106 uses the SOC acquired in step S210 or S230 and the charge acceptability acquired in step S250 to indicate a relationship between the SOC of the battery that has not been discharged and the charge acceptability. Update.

    FIG. 10 is an explanatory diagram showing the update of the map showing the relationship between the SOC and the charge acceptance. Here, updating of the map of the first battery 110 will be described. The map update unit 108 of the control unit 100 calculates the charge acceptability in the SOC (Q1) acquired in step S230 from the charge amount of the first battery 110 in step S250, and plots it on the graph (point P1). Next, the amount of charge to the first battery 110 is added to the SOC (Q1), and the SOC value (Q2) for the point P2 to be plotted next is calculated. Similarly, charge acceptability when the SOC value is Q2 is calculated from the amount of charge to the first battery 110 and plotted on a graph (point P2). Similarly, charge acceptability when the SOC value is Q3 is calculated and plotted on a graph (point P3). By smoothly connecting the points P1, P2, and P3, a map indicating the relationship between the new SOC and the charge acceptance is created. The map update unit 108 of the control unit 100 uses this map to update a map indicating the relationship between the SOC and the charge acceptance.

  In the present embodiment, the map update unit 108 of the control unit 100 creates a map showing the relationship between the updated SOC and the charge acceptability by smoothly connecting three points, but the number of points to be connected may be greater than three. Good. Further, the map update unit 108 of the control unit 100 may acquire the points P1, P2, and P3 every predetermined time Δt. In this case, the map updating unit 108 of the control unit 100 may calculate the SOC value Q2 when the point P2 is acquired by adding a value obtained by multiplying the current amount at the point P1 by Δt.

  As described above, according to the second embodiment, when there is a battery that has not been discharged, the map update unit 108 of the control unit 100 measures the OCV of the battery, acquires the SOC from the OCV, and further regenerates energy. By charging the battery as a current, the charge acceptability is acquired and the map indicating the relationship between the SOC of the battery and the charge acceptability is updated, so that the discharge control can be executed with high accuracy.

  The embodiments of the present invention have been described above based on some examples. However, the above-described embodiments of the present invention are for facilitating the understanding of the present invention and limit the present invention. It is not a thing. The present invention can be changed and improved without departing from the spirit and scope of the claims, and it is needless to say that the present invention includes equivalents thereof.

DESCRIPTION OF SYMBOLS 10 ... Vehicle battery system 100 ... Control part 101 ... Map memory | storage part 102 ... SOC acquisition part 103 ... Current consumption acquisition part 104 ... Charging start time estimation part 105 ... Total discharge amount prediction part 106 ... Battery determination part 107 ... Battery discharge control part DESCRIPTION OF SYMBOLS 108 ... Map update part 110 ... 1st battery 120 ... 2nd battery 130 ... Alternator 140 ... Starter 150 ... Auxiliary machine 160 ... 1st switch 165 ... 2nd switch 170 ... 1st ammeter 175 ... 2nd ammeter

Claims (8)

A plurality of batteries having different amounts of change in charge acceptance with respect to the amount of discharge;
An auxiliary machine,
A generator,
A map storage unit for storing a map indicating a relationship between each SOC and charge acceptability for each of the plurality of batteries;
An SOC acquisition unit for acquiring each SOC for each of the plurality of batteries;
A current consumption acquisition unit for acquiring current consumption of the auxiliary machine;
A charging start time estimation unit for estimating the time to start charging the plurality of batteries by the generator;
Based on the consumption current acquired by the consumption current acquisition unit and the time until the start of charging estimated by the charging start time estimation unit, the total discharge amount discharged from the plurality of batteries until the start of charging is predicted. A total discharge prediction unit;
Based on the SOC acquired by the SOC acquisition unit, the map stored in the map storage unit, and the total discharge amount predicted by the total discharge amount prediction unit, the total charge acceptability of the plurality of batteries is calculated. A battery determination unit that determines one or more batteries to be discharged before the start of charging, from among the plurality of batteries so as to be equal to or greater than a predetermined value;
A battery discharge control unit for executing discharge from one or more batteries determined by the battery determination unit;
A vehicle battery system comprising: The vehicle battery system according to claim 1,
The battery determination unit is a vehicle battery system that determines one or more batteries to be discharged from the plurality of batteries so that a total charge acceptability of the plurality of batteries is maximized. The vehicle battery system according to claim 2,
The number of the batteries is two,
The battery determination unit
(A) first charge acceptability after discharging the total discharge amount from only the first battery, and (b) second charge acceptability after discharging the total discharge amount from only the second battery. And (c) a third charge acceptability after discharging the total discharge amount from both the first battery and the second battery,
(D) When the first charge acceptability is the highest, only the first battery is determined as a battery to be discharged, and (e) the battery to be discharged when the second charge acceptability is the highest. And (f) a vehicle battery system that determines both the first battery and the second battery as batteries to be discharged when the third charge acceptability is greatest. The vehicle battery system according to any one of claims 1 to 3,
When the battery discharge control unit does not discharge at least one of the plurality of batteries,
Obtain the OCV of the battery that does not discharge,
Determining a SOC value of the battery that does not perform the discharge using a predetermined relationship between the SOC and the OCV;
Charge the battery that does not discharge and measure the charge acceptability of the battery that does not discharge,
Updating the map of batteries not discharging;
A map updating unit;
Vehicle battery system. A control method of a vehicle battery system including a plurality of batteries having different amounts of change in charge acceptability with respect to a discharge amount,
Obtaining each SOC for each of the plurality of batteries;
Get the current consumption of the auxiliary machine,
Estimating the time to start charging the plurality of batteries by the generator,
Based on the current consumption of the auxiliary machine and the time until the start of charging, predict the total discharge amount discharged from the plurality of batteries until the start of charging,
Based on the acquired SOC, a map indicating the relationship between the SOC and the charge acceptance for a plurality of batteries, and the predicted total discharge amount, a total charge acceptance of the plurality of batteries is predetermined. Determining one or more batteries to be discharged from the plurality of batteries until the start of charging, so as to be equal to or greater than the value;
Discharging from the determined one or more batteries;
A control method for a vehicle battery system. The vehicle battery system control method according to claim 5,
A control method for a vehicle battery system, wherein one or more batteries are determined from among the plurality of batteries such that a total charge acceptability of the plurality of batteries is maximized. The vehicle battery system control method according to claim 6,
The number of the batteries is two,
(A) first charge acceptability after discharging the total discharge amount from only the first battery, and (b) second charge acceptability after discharging the total discharge amount from only the second battery. And (c) a third charge acceptability after discharging the total discharge amount from both the first battery and the second battery,
(D) Discharge using only the first battery when the first charge acceptability is greatest, and (e) Discharge using only the second battery when the second charge acceptability is greatest. (F) A control method for a vehicle battery system, wherein discharging is performed using both the first battery and the second battery when the third charge acceptance is the highest. In the vehicle battery system control method according to any one of claims 5 to 7,
When at least one of the plurality of batteries is not discharged,
Obtain the OCV of the battery that is not discharged,
Determining a SOC value of the battery that is not discharged using a predetermined relationship between SOC and OCV;
Charge the battery that does not discharge, measure the charge acceptance,
Updating the map of batteries that do not discharge,
A control method for a vehicle battery system.

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