JP2013031248A - Battery device hysteresis reduction system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery device hysteresis reduction system that reduces battery hysteresis.SOLUTION: The battery device hysteresis reduction system includes: a battery A rechargeable with regenerated power from a regeneration system 30 during vehicle braking; a battery B of a different type from the battery A; a charging circuit 11 provided with a switch SW1 and configured to charge the battery B from the battery A; and an ECU 20 for controlling the switch SW1 in accordance with a state of the battery A. When regeneration acceptance of the battery A is low, the ECU 20 improves the regeneration acceptance of the battery A by turning on the switch SW1 to charge the battery B from the battery A via the charging circuit 11.

Description

  The present invention relates to a hysteresis reduction system for a battery device that reduces battery hysteresis.

  A plurality of storage batteries (secondary batteries; hereinafter referred to as batteries) are connected in series to an electric vehicle such as an electric vehicle (EV) that runs only with a motor or a hybrid vehicle (HEV, PHEV) that runs with a motor and an engine. A battery device for driving is mounted. As the battery of the battery device, one type of battery is usually used.

JP 2008-029071 A

  Since the battery has hysteresis depending on the charge / discharge state, there is a state where the battery does not accept regeneration. For this reason, there is a case where electric power due to regeneration cannot be charged, and as a result, the cruising distance of the vehicle (the distance traveled without supplying electricity or fuel from the outside) is shortened. In addition, if the regeneration is not accepted, the regeneration is restricted, so that the regeneration amount when the brake is depressed is not constant.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a hysteresis reduction system for a battery device that reduces battery hysteresis.

A hysteresis reduction system for a battery device according to a first aspect of the present invention for solving the above problems is provided:
A first battery for charging electric power regenerated during braking of the vehicle;
A second battery of a different type from the first battery;
A first charging circuit that has a first switch and charges the second battery from the first battery;
Control means for controlling the first switch according to the state of the first battery,
When the regenerative acceptance of the first battery is poor, the control means turns on the first switch, and connects the first battery to the second battery via the first charging circuit. Charging is performed to improve the regenerative acceptance of the first battery.

A hysteresis reduction system for a battery device according to a second invention that solves the above-described problems is as follows.
In the hysteresis reduction system for a battery device according to the first invention,
The first battery is a type of battery having better input / output characteristics than the second battery,
The second battery is a battery having a smaller hysteresis than the first battery.

A hysteresis reduction system for a battery device according to a third invention for solving the above-described problem is provided.
In the hysteresis reduction system for a battery device according to the first or second invention,
The control means is characterized in that, when the first battery is not discharged after charging the first battery, the regenerative acceptance of the first battery is poor.

A hysteresis reduction system for a battery device according to a fourth invention for solving the above-described problem is
In the hysteresis reduction system for a battery device according to the first or second invention,
The control means supplies a predetermined first current value to the first battery for a predetermined time, detects a change in the voltage of the first battery before and after the predetermined time, and the change in the voltage is detected. When it is larger than the predetermined voltage change value, that is, when the charging resistance is larger than the predetermined charging resistance value, the regeneration acceptability is poor.

A hysteresis reducing system for a battery device according to a fifth invention for solving the above-described problems,
In the hysteresis reduction system for a battery device according to the third or fourth invention,
The control means is configured such that the charging rate of the first battery is equal to or higher than a predetermined first charging rate, or the charging rate of the first battery is equal to or higher than a predetermined first charging rate, and When the temperature of the first battery is equal to or lower than a predetermined first temperature, charging from the first battery to the second battery is performed using a current equal to or higher than a predetermined second current value. It is characterized by.

A hysteresis reduction system for a battery device according to a sixth invention for solving the above-described problem,
In the hysteresis reduction system for a battery device according to any one of the first to fifth inventions,
And a second charging circuit having a second switch for charging the first battery from the second battery,
The control means turns on the second switch when the first battery is uncharged after discharging from the first battery, and turns on the second switch via the second charging circuit. The battery is charged from the first battery to the first battery.

A hysteresis reducing system for a battery device according to a seventh invention for solving the above-described problem is provided.
In the hysteresis reduction system for a battery device according to the sixth invention,
The control means is configured such that the charging rate of the first battery is equal to or lower than a predetermined second charging rate, or the charging rate of the first battery is equal to or lower than a predetermined second charging rate, and When the temperature of the first battery is equal to or higher than a predetermined second temperature, charging from the second battery to the first battery is performed using a current smaller than a predetermined third current value. It is characterized by.

  According to the first to fourth inventions, when the regenerative acceptability of the first battery is poor, charging from the first battery to the second battery is performed. Therefore, the regenerative acceptability of the first battery is always improved. Therefore, the electric power generated by the regeneration can be charged to the first battery without waste, and the cruising distance can be extended. Further, by preventing a state in which regeneration due to hysteresis is not accepted, the amount of regeneration when the brake is stepped on can be made constant.

  According to the fifth invention, when the charging rate of the first battery is equal to or higher than the predetermined first charging rate, or the charging rate of the first battery is equal to or higher than the predetermined first charging rate, and When the temperature of the first battery is equal to or lower than the predetermined first temperature, charging from the first battery to the second battery is performed using a current equal to or higher than the predetermined second current value. The hysteresis of the input characteristics of the first battery is easily eliminated, and as a result, the regenerative acceptance of the first battery can be further improved.

  According to the sixth invention, after the discharge from the first battery and before the charge to the first battery, the second battery to the first battery is performed. Since charging is performed, the output characteristics of the first battery can always be improved.

  According to the seventh invention, when the charging rate of the first battery is equal to or lower than the predetermined second charging rate, or the charging rate of the first battery is equal to or lower than the predetermined second charging rate, and When the temperature of the first battery is equal to or higher than the predetermined second temperature, charging from the second battery to the first battery is performed using a current smaller than the predetermined third current value. As a result, the output characteristics of the first battery can be further improved.

It is a schematic block diagram which shows the hysteresis reduction system of the battery apparatus which concerns on this invention. It is a flowchart explaining the control in the hysteresis reduction system of the battery apparatus shown in FIG. FIG. 3 is a flowchart for explaining control in the hysteresis reduction system for the battery device shown in FIG. 1, and is a flowchart of a portion branched from a point P in FIG. 2. (A), (b) is a map used by the control shown in FIG. 2, FIG. It is a figure which shows charge (A-> B) by the control shown to FIG. 2, FIG. It is a figure which shows charge (B-> A) by the control shown in FIG. 2, FIG.

  Hereinafter, with reference to FIGS. 1-6, embodiment of the hysteresis reduction system of the battery apparatus which concerns on this invention is described. The hysteresis reduction system for a battery device according to the present invention is applicable not only to electric vehicles but also to electric vehicles such as hybrid vehicles.

Example 1
FIG. 1 is a schematic configuration diagram illustrating a hysteresis reduction system for a battery device according to the present embodiment. FIGS. 2 and 3 are flowcharts illustrating control in the hysteresis reduction system for the battery device illustrated in FIG. 4 (a) and 4 (b) are maps used in the control shown in FIGS. 2 and 3, and FIGS. 5 to 6 are diagrams for explaining the control shown in FIGS.

  The hysteresis reduction system for a battery device according to the present embodiment monitors a battery device 10 having a first battery A and a second battery B, and the batteries A and B, and a charging circuit 11 (a first circuit described later). And an ECU (Electronics Control Unit) 20 that controls the reverse charging circuit 12 (second charging circuit). A regenerative system 30 that generates regenerative power is connected to the battery device 10, and the ECU 20 switches switches SW <b> 1 and SW <b> 2 of the charging circuit 11 and the reverse charging circuit 12, which will be described later, according to the state of each battery A and B. Control is performed to charge and discharge between batteries A and B to reduce hysteresis. In the case of an electric vehicle, the regeneration system 30 corresponds to a generator (or a drive motor / generator) or the like.

  The battery A may be composed of a single storage battery, or may be composed of a plurality of storage batteries as long as they are of the same type. Similarly, the battery B may be composed of a single storage battery, or may be composed of a plurality of storage batteries as long as they are of the same type. However, the battery A and the battery B must be composed of different types of storage batteries. Specifically, as the battery A directly connected to the regenerative system 30, a battery having a large hysteresis but a good input / output characteristic is selected. On the other hand, as the battery B connected to the battery A via the charging circuit 11 and the reverse charging circuit 12 described later, a battery B that has poor input / output characteristics but low hysteresis is selected.

A battery A having a large hysteresis but good input / output characteristics is shown below.
(1) Positive electrode: Various lithium oxides, Negative electrode: Lithium titanate battery (2) Positive electrode: Lithium iron phosphate, Negative electrode: Carbon battery (3) Nickel metal hydride battery (4) Lead storage battery Besides, olivine structure (phosphoric acid An active material having iron or the like) is considered to have hysteresis.

On the other hand, the battery B that has poor input / output characteristics but little or no hysteresis is shown below.
(1) Positive electrode: various lithium oxides, negative electrode: carbon battery (2) Alkaline manganese battery

  In the battery device 10, the battery A is directly connected to the regenerative system 30, and the regenerative power from the regenerative system 30 is directly charged to the battery A. Battery B has one pole connected to one pole of battery A via charging circuit 11 and reverse charging circuit 12, and the other pole connected to the other pole of battery A via shared line CL. The battery A is connected to the battery B through the charging circuit 11 and the shared line CL, and the battery B is charged from the battery B through the reverse charging circuit 12 and the shared line CL. That is, the battery A and the battery B are connected in parallel via the charging circuit 11, the reverse charging circuit 12, and the shared line CL, and can be charged and discharged with each other.

  The charging circuit 11 includes a switch SW1 for turning on / off the charging circuit 11, a diode DI1 for preventing a backflow of a flowing current, a variable resistor VR1 for adjusting a flowing current amount, and an ammeter AM1 for measuring a current value. Have. In order to keep the input characteristics of the battery A good, it is desirable that the battery B is charged by sending a large pulse current from the battery A to the battery B. For example, the pulse current is generated in the charging circuit 11. A pulse generator or the like may be provided.

  The reverse charging circuit 12 includes a switch SW2 for turning on / off the reverse charging circuit 12, a diode DI2 for preventing a reverse flow of the flowing current, a variable resistor VR2 for adjusting the flowing current amount, and a current for measuring a current value. It has a total AM2 and a boost converter VC that increases the voltage. The driving battery device 10 is normally set to a high voltage, but the battery B may have a lower voltage than the battery A by providing the boost converter VC.

  The ECU 20 monitors the charge / discharge states, temperatures, and voltages of the batteries A and B, and calculates an SOC (State of Charge) based on the voltages of the batteries A and B. And by switching the switch SW1 or the switch SW2 according to the charge / discharge state, temperature, voltage and SOC, the charging circuit 11 or the reverse charging circuit 12 is selected, and charging from the battery A to the battery B, or Charging from the battery B to the battery A is selected, and by performing such control, the hysteresis of the battery A is reduced and the regenerative acceptance of the battery A is always improved.

  Here, with reference to the flowcharts of FIGS. 2 and 3, the maps of FIGS. 4A and 4B, and the control examples of FIGS. To do. 4A is a map for determining, in the battery A, the SOC when charging from the battery A to the battery B from the relationship with the temperature. FIG. It is a map which determines SOC when charging from B to the battery A from the relationship with temperature.

  The temperature and voltage of the battery A are measured (step S1).

  After charging the battery A (regenerative charging from the regenerative system 30 to the battery A and charging from the battery B to the battery A, which will be described later), check whether the battery A is not discharged, and after charging the battery A, If it is a discharge, the process proceeds to the next step S3. If not, the control is terminated (step S2). That is, the ECU 20 monitors the charging / discharging state of the battery A. When the battery A is not discharged after charging, for example, a flag is set to indicate that the regenerative acceptance of the battery A is poor.

  On the other hand, the battery A may be actually measured, and the state of the battery A may be monitored based on the measurement result, and the battery A may have poor regenerative acceptability. For example, a predetermined current value (first current value; 10A as an example) is supplied to the battery A for a predetermined time (as an example, 5 seconds), and a change in the voltage of the battery A before and after the predetermined time is detected. However, when the voltage change is larger than a predetermined voltage change value, that is, when the charging resistance is larger than the predetermined charging resistance value, for example, a flag may be set and the regeneration acceptability may be poor.

  It is confirmed whether a certain time (for example, one hour) has elapsed since the previous switching, that is, the switching of the switch SW1 or SW2, and if the certain time has elapsed, the process proceeds to the next step S4, and the certain time has elapsed. If not, the control is terminated (step S3). This is to avoid frequent switching, that is, frequent charge / discharge. This fixed time may be set according to the characteristics of the battery.

  If a certain time has elapsed since the previous switching, the SOC is calculated from the measured voltage of the battery A. If the calculated SOC of the battery A is 70% (first charging rate) or more, the process proceeds to the next step S5. If it is less than 70%, the process proceeds to step S12 (step S4). Although 70% is an example numerical value, it is a lower limit value of the SOC when charging from the battery A to the battery B is started.

  If the SOC of the battery A is 70% or more, the voltage of the battery B is measured (step S5).

  The SOC is calculated from the measured voltage of the battery B. If the calculated SOC of the battery B is 80% or more, the control is terminated, and if it is less than 80%, the process proceeds to the next step S7 (step S6). This 80% is a numerical value as an example, and is a judgment value for avoiding overcharging of the battery B before charging.

  If the SOC of the battery B is less than 80%, the SOC (X%) for switching the battery A is determined based on the map 1 shown in FIG. 4A, that is, based on the relationship with the temperature ( Step S7). For example, if the measured temperature of the battery A is 25 ° C., the SOC for switching the battery A is determined to be X = 90%. As an example, X% is set in a range larger than 70% when the first charging rate is 70% as described above.

  Using the determined SOC (X%) of the battery A, if the calculated SOC of the battery A is X% or less, the control is terminated, and if exceeding the X%, the process proceeds to the next step S9 (step S8).

  If the SOC of the battery A exceeds X%, switching to the charging circuit 11 is performed, and charging from the battery A to the battery B is performed (step S9). The region where the SOC of the battery A exceeds X% is regenerative, but at that temperature, the regenerative acceptability is poor. In this embodiment, in order to improve the regenerative acceptability in this region. , Power is being transferred from battery A to battery B. Therefore, as shown in FIG. 5, when the switch SW1 is turned on, the battery A and the battery B are connected via the charging circuit 11 and the shared line CL, and the battery A to the battery B are connected by the charging path indicated by C2. Is charging to.

  The battery A has a high SOC (for example, when the above-described SOC is 70% (first charging rate) or higher) and low temperature (for example, 40 ° C. (first temperature) or lower). If discharging is performed at a large current (for example, 10 A (second current value) or more), that is, charging from the battery A to the battery B, the hysteresis of the input characteristics is easily eliminated, and as a result , Input characteristics are further improved. On the other hand, even if the above conditions, i.e., high SOC, low temperature, and large current are not satisfied, as described above, discharging after charging of battery A, i.e., from battery A to battery B after charging of battery A, is performed. Even if charging is performed, the hysteresis of the input characteristics is improved and the input characteristics are improved.

  If the SOC of battery B is 90% or more, the control is terminated, and if it is less than 90%, the process proceeds to step S11 (step S10). That is, charging from the battery A to the battery B is performed until the SOC of the battery B reaches 90% or more. This 90% is a numerical value as an example, and is a judgment value for avoiding overcharging of the battery B during charging.

  If the SOC of battery A is less than 50%, the control is terminated, and if it is 50% or more, the process returns to step S9 (step S11). That is, charging from the battery A to the battery B is performed until the SOC of the battery A becomes less than 50%. The 50% is an example numerical value, but is a lower limit value for avoiding overdischarge of the battery A and deterioration of output characteristics during discharge. In addition, if the capacity of the battery A is reduced too much due to the discharge, it becomes impossible to run, so there is a meaning of securing a minimum capacity for running.

  In step S4, if the calculated SOC of the battery A is less than 70%, after the discharge from the battery A (the discharge from the battery A to the driving motor and the discharge from the battery A to the battery B described above), It is confirmed whether or not the battery A is uncharged. If the battery A is uncharged after discharging from the battery A, the process proceeds to the next step S13. Otherwise, the control is terminated (step S12). That is, the ECU 20 monitors the charge / discharge state of the battery A. If the battery A is not charged after the battery A is discharged, for example, a flag is set.

  It is confirmed whether the SOC of the battery A is 30% (second charge rate) or less. If the SOC of the battery A is 30% or less, the process proceeds to the next step S14, and if it exceeds 30%, the control is terminated. (Step S13). The 30% is an example numerical value, but is an upper limit value of SOC when charging from the battery B to the battery A is started.

  If the SOC of battery A is 30% or less, the voltage of battery B is measured (step S14).

  The SOC is calculated from the measured voltage of the battery B. If the calculated SOC of the battery B is 10% or less, the control is terminated, and if it exceeds 10%, the process proceeds to the next step S16 (step S15). This 10% is a numerical value as an example, and is a judgment value for avoiding overdischarge from the battery B.

  When the SOC of the battery B exceeds 10%, the SOC (Y%) for switching the battery A is determined based on the map 2 shown in FIG. 4B, that is, based on the relationship with the temperature ( Step S16). For example, if the measured temperature of the battery A is 25 ° C., the SOC for switching the battery A is determined as Y = 10%. As an example, Y% is set in a range smaller than 30% when the second charging rate is 30% as described above.

  Using the determined SOC (Y%) of the battery A, if the calculated SOC of the battery A is Y% or more, the control is terminated, and if it is less than Y%, the process proceeds to the next step S18 (step S17).

  If the SOC of the battery A is less than Y%, switching to the reverse charging circuit 12 is performed, and charging from the battery B to the battery A is performed (step S18). Here, when the SOC of the battery A is low, power is transferred from the battery B to the battery A. Therefore, as shown in FIG. 6, when the switch SW2 is turned on, the battery A and the battery B are connected via the reverse charging circuit 11 and the shared line CL, and the battery B is connected to the battery B by the charging path indicated by C3. Charging A

  In addition, when the battery A has a low SOC (for example, when the above-described SOC is 30% (second charge rate) or higher) or high temperature (for example, 40 ° C. (second temperature) or higher), If charging is performed at a low current (for example, 10 A (third current value) or less), that is, charging from the battery B to the battery A, the hysteresis of the output characteristics is easily eliminated, and as a result The output characteristics are further improved. On the other hand, even if the above conditions, that is, low SOC, high temperature, and low current are not satisfied, as described above, charging is performed after battery A is discharged, that is, battery A is discharged from battery B to battery A. Even if charging is performed, the hysteresis of the output characteristics is improved and the output characteristics are improved.

  If the SOC of battery B is 10% or less, the control is terminated, and if it exceeds 10%, the process proceeds to step S20 (step S19). That is, the charging from the battery B to the battery A is performed until the SOC of the battery B becomes 10% or less. This 10% is a numerical value as an example, and is a judgment value for avoiding overdischarge from the battery B.

  When the SOC of the battery A exceeds 50%, the control is terminated, and when it is 50% or less, the process returns to step S18 (step S20). That is, charging from the battery B to the battery A is performed until the SOC of the battery A exceeds 50%. The 50% is an example numerical value, but is an upper limit value for avoiding overcharging of the battery A and deterioration of input characteristics during charging.

  In the present embodiment, the above control is carried out periodically (for example, every 5 minutes), whereby the power of the battery A is transferred to the battery B based on the state of the batteries A and B. Thereby, the hysteresis of the battery A is reduced, and the regenerative acceptance of the battery A from the regenerative system 30 is always improved. As a result, the regenerated electric power is effectively charged and used, and the cruising range of the vehicle is increased.

  Moreover, since the regenerative acceptance of the battery A is always improved by the above-described control, the regenerative restriction can be suppressed, and as a result, the regenerative amount when the brake is depressed can be made constant. When regeneration from the regeneration system 30 is being performed, as shown in FIG. 1, both the switches SW1 and SW2 are turned off, and the battery A is charged through the charging path indicated by C1.

  The hysteresis reduction system for a battery device according to the present invention is suitable for a drive battery device mounted on an electric vehicle, but is not limited to an electric vehicle and can also be applied to an electric vehicle such as a hybrid vehicle.

DESCRIPTION OF SYMBOLS 10 Battery apparatus 11 Charging circuit 12 Reverse charging circuit 20 ECU
30 regeneration system

Claims (7)

A first battery for charging electric power regenerated during braking of the vehicle;
A second battery of a different type from the first battery;
A first charging circuit that has a first switch and charges the second battery from the first battery;
Control means for controlling the first switch according to the state of the first battery,
When the regenerative acceptance of the first battery is poor, the control means turns on the first switch, and connects the first battery to the second battery via the first charging circuit. A system for reducing hysteresis of a battery device, wherein charging is performed to improve regenerative acceptance of the first battery. The hysteresis reduction system for a battery device according to claim 1,
The first battery is a type of battery having better input / output characteristics than the second battery,
The battery device hysteresis reduction system, wherein the second battery is a battery of a type having a smaller hysteresis than the first battery. In the hysteresis reduction system for a battery device according to claim 1 or 2,
In the battery device according to claim 1, wherein when the first battery is not discharged after charging the first battery, the control means has a case where the regenerative acceptance of the first battery is poor. Hysteresis reduction system. In the hysteresis reduction system for a battery device according to claim 1 or 2,
The control means supplies a predetermined first current value to the first battery for a predetermined time, detects a change in the voltage of the first battery before and after the predetermined time, and the change in the voltage is detected. A hysteresis reduction system for a battery device, characterized in that when the voltage change value is greater than a predetermined voltage change value, the regenerative acceptance is poor. In the hysteresis reduction system for a battery device according to claim 3 or 4,
The control means is configured such that the charging rate of the first battery is equal to or higher than a predetermined first charging rate, or the charging rate of the first battery is equal to or higher than a predetermined first charging rate, and When the temperature of the first battery is equal to or lower than a predetermined first temperature, charging from the first battery to the second battery is performed using a current equal to or higher than a predetermined second current value. A hysteresis reduction system for a battery device. In the hysteresis reduction system for a battery device according to any one of claims 1 to 5,
And a second charging circuit having a second switch for charging the first battery from the second battery,
The control means turns on the second switch when the first battery is uncharged after discharging from the first battery, and turns on the second switch via the second charging circuit. A battery system hysteresis reduction system characterized in that the first battery is charged from the first battery. The hysteresis reduction system for a battery device according to claim 6,
The control means is configured such that the charging rate of the first battery is equal to or lower than a predetermined second charging rate, or the charging rate of the first battery is equal to or lower than a predetermined second charging rate, and When the temperature of the first battery is equal to or higher than a predetermined second temperature, charging from the second battery to the first battery is performed using a current smaller than a predetermined third current value. A hysteresis reduction system for a battery device.

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