JP2018156744A - Power supply system - Google Patents

Abstract

A power supply system capable of recovering reversible characteristic deterioration of a storage battery is provided. A storage battery (2) and a control unit (3) for controlling charging / discharging of the storage battery (2) are provided. The active material 40 constituting at least one electrode 4 of the storage battery 2 includes a high gradient region AH having a relatively high potential gradient and a low gradient region AL having a lower potential gradient than the high gradient region AH. The storage battery 2 has reversible characteristic deterioration when the charge rate SOC is a low gradient charge rate SOCL corresponding to the low gradient region AL, and recovers when the charge rate SOC is high gradient charge rate SOCH. Control unit 3 controls charging / discharging of storage battery 2 to change charging rate SOC from low gradient charging rate SOCL to high gradient charging rate SOCH. Thereby, the characteristic deterioration of a storage battery is recovered. [Selection] Figure 4

Description

  The present invention relates to a power supply system including a storage battery and a control unit that controls charging and discharging of the storage battery.

  Conventionally, a power supply system including a storage battery and a control unit that controls charging and discharging of the storage battery is known (see Patent Document 1 below). Some of the above storage batteries have a pair of positive and negative electrodes and a metal atom (lithium) that is inserted and removed from the active material constituting the electrodes, such as a lithium ion secondary battery. .

  When the storage battery is charged and discharged, metal atoms are desorbed into the active material, and the concentration of metal atoms in the active material changes. Along with this, the potential of the active material changes. In the above storage battery, the difference in potential between the positive electrode and the negative electrode becomes the output voltage.

  In recent years, development of a storage battery having a small potential gradient of the active material (rate of change in potential when the charge rate is changed: see FIG. 4) has been promoted. Such a storage battery is characterized in that the output voltage does not change significantly even when charging and discharging because the potential gradient of the active material is small.

Japanese Patent Laid-Open No. 2006-143546

  However, as a result of studies by the present inventors, it has been found that the storage battery may be reversibly deteriorated when charged and discharged with a large current. That is, when charging / discharging with a large current, the concentration of metal atoms in the active material may become non-uniform (see FIG. 5). In this case, since the potential gradient of the active material is small, a high potential difference does not occur between the portion where the concentration of metal atoms is high and the portion where the concentration is low, and a force for reducing this potential difference is unlikely to occur. Therefore, a local battery reaction is less likely to occur, where the variation in the concentration of metal atoms in the active material is reduced. In this state, it becomes difficult to charge and discharge the storage battery efficiently.

  This invention is made | formed in view of this subject, and aims to provide the power supply system which can recover | restore reversible characteristic deterioration of a storage battery.

One aspect of the present invention is a storage battery (2),
A control unit (3) for controlling charging and discharging of the storage battery,
The storage battery includes a pair of electrodes (4) of a positive electrode (4 _P ) and a negative electrode (4 _N ) each including an active material (40), and constitutes at least one of the pair of electrodes. The active material includes a high gradient region (A _H ) having a relatively high potential gradient, which is a rate of change in potential (V) when the charge rate (SOC) of the storage battery is changed, and the high gradient region And a low gradient region ( _AL ) where the potential gradient is lower than
The storage battery has a reversible characteristic deterioration when the charge rate is a low gradient charge rate (SOC _L ) corresponding to the low gradient region, and the charge rate is a high gradient charge rate corresponding to the high gradient region. (SOC _H ) recovers the above characteristics deterioration,
The control unit is configured to change the charging rate from the low gradient charging rate to the high gradient charging rate by controlling charging / discharging of the storage battery, and to perform a recovery process for recovering the characteristic deterioration. , In the power supply system (1).

The control unit of the power supply system is configured to perform the recovery process. In this recovery process, charging / discharging of the storage battery is controlled, and the charging rate is changed from the low gradient charging rate to the high gradient charging rate.
In this way, the active material can be transferred from the low gradient region to the high gradient region. In the high gradient region, the potential gradient is higher than that in the low gradient region (see FIG. 4). Therefore, a large potential difference is generated between a portion where the concentration of metal atoms in the active material is high and a portion where the concentration is low. Therefore, in order to reduce this potential difference, a local battery in which metal atoms are desorbed from a portion having a high concentration in the active material to the electrolyte and at the same time a metal atom is inserted from the electrolyte to a portion having a low concentration in the active material. Reaction occurs and concentration variation is reduced. Therefore, reversible characteristic deterioration of the storage battery can be recovered.

As described above, according to this aspect, it is possible to provide a power supply system that can recover reversible characteristic deterioration of a storage battery.
In addition, the code | symbol in the parenthesis described in the means to solve a claim and a subject shows the correspondence with the specific means as described in embodiment mentioned later, and limits the technical scope of this invention. It is not a thing.

FIG. 2 is a circuit diagram of a power supply system in the first embodiment. The conceptual diagram of the storage battery in discharge in Embodiment 1. FIG. The conceptual diagram of the storage battery in charge in Embodiment 1. FIG. The graph showing the relationship between the electric potential V and charge rate SOC of a positive electrode and a negative electrode in Embodiment 1. FIG. The conceptual diagram of the storage battery in the primary degradation state in Embodiment 1. FIG. The figure which represented the state of FIG. 5 simply. 5 is a flowchart of a control unit when performing recovery processing in the first embodiment. The flowchart of a control part at the time of judging whether the storage battery is in a primary deterioration state in Embodiment 1. FIG. The graph showing the relationship between the deterioration rate of a storage battery and temperature in Embodiment 1. FIG. The conceptual diagram of the storage battery after recovery | restoration in Embodiment 1. FIG. 6 is a flowchart of a control unit in the second embodiment. The graph showing the relationship between the voltage of a storage battery and time in Embodiment 3. 10 is a flowchart of a control unit in the third embodiment. 10 is a flowchart of a control unit in the fourth embodiment. 10 is a flowchart of a control unit in the fifth embodiment. 10 is a flowchart of a control unit in the sixth embodiment. 10 is a flowchart of a control unit in the seventh embodiment. FIG. 10 is a circuit diagram of a power supply system in an eighth embodiment. 10 is a flowchart of a control unit in the eighth embodiment. The graph showing the time change of the voltage and charging rate in Embodiment 9. FIG. The circuit diagram of the power supply system in Embodiment 9. FIG. 10 is a flowchart of a control unit in the ninth embodiment. 11 is a graph showing the relationship between the potential of the active material and the charging rate in Embodiment 10. The flowchart of the control part in Embodiment 11. FIG. The flowchart of the control part in Embodiment 12. FIG. The flowchart of the control part in Embodiment 13. FIG. The flowchart of the control part in Embodiment 14. FIG. The flowchart of the control part in Embodiment 15. FIG.

(Embodiment 1)
An embodiment according to the power supply system will be described with reference to FIGS. As shown in FIG. 1, the power supply system 1 of this embodiment includes a storage battery 2 and a control unit 3. The control unit 3 controls charging / discharging of the storage battery 2.

As shown in FIG. 2, the storage battery 2 includes a pair of electrodes 4 including a positive electrode 4 _P and a negative electrode 4 _N. Each of these electrodes 4 has an active material 40. As shown in FIG. 4, the active material 40 _N constituting one electrode 4 (in this embodiment, the negative electrode 4 _N ) of the pair of electrodes 4 _P and 4 _N has a high gradient region A _H and a low gradient region A _L. There is. The high gradient region A _H is a region where the potential gradient, which is the rate of change of the potential V when the charge rate SOC of the storage battery 2 is changed, is relatively high. The low gradient region A _L is a region having a lower potential gradient than the high gradient region A _H. That is, in FIG. 4, the region where the slope of the curve is substantially 0 is the low gradient region A _L , and the region where the slope is steep is the high gradient region A _H.

When the charge rate SOC is the low gradient charge rate SOC _L corresponding to the low gradient region A _L , the storage battery 2 undergoes reversible characteristic deterioration. That is, as shown in FIG. 5, the concentration variation of metal atoms (lithium atoms) in the active material 40 _N occurs, and the storage battery 2 has a portion with a high charge rate SOC and a portion with a low charge rate SOC. This characteristic deterioration, the charging rate SOC restored to the the high gradient charging rate SOC _H. That is, since the high gradient region A potential gradient is high at _H (see FIG. 4), between the high concentration part and the lower part of the metal atoms, high electric potential difference occurs. Accordingly, the metal atoms move in the electrode 4 so that this potential difference becomes small, and the reversible characteristic deterioration of the storage battery 2 is recovered.

Control unit 3 (see FIG. 1) by controlling the charging and discharging of the storage battery 2, to change the charging rate SOC of the low gradient charging rate SOC _L to a high-gradient charging rate SOC _H. Thereby, the characteristic deterioration of the storage battery 2 is recovered.

  The power supply system 1 of this embodiment is a vehicle-mounted power supply system for mounting on a vehicle. Moreover, the storage battery 2 of this embodiment is a lithium ion secondary battery. As shown in FIG. 1, an auxiliary power source 14, a starter 15, an auxiliary device 13 such as an air conditioner, a generator 12, and switches SW <b> 1 to SW <b> 3 are mounted on the vehicle. The auxiliary power source 14 is a lead battery. The starter 15 is provided to start an engine (not shown).

  In addition, an inverter (not shown) and a three-phase AC motor are mounted on the vehicle. In this embodiment, the inverter is used to convert the DC power supplied from the storage battery 2 into AC power and drive the three-phase AC motor. As a result, the vehicle is running.

The power supply system 1 includes a voltage sensor 5 _V , a current sensor 5 _I , a temperature sensor 5 _T , and a timer 19 in addition to the storage battery 2 and the control unit 3. The control unit 3 is connected to a host ECU mounted on the vehicle. The controller 3 controls the on / off operation of the switches SW1 to SW3. Thereby, charging / discharging of the storage battery 2 is controlled. During charging, the first switch SW1 is turned on. Thereby, the storage battery 2 is charged using the generator 12. At the time of discharging, the second switch SW2 and the third switch SW3 are turned on. Thereby, the electric power stored in the storage battery 2 is transferred to the auxiliary power supply 14, and the storage battery 2 is discharged.

Further, as shown in FIG. 2, the storage battery 2 includes a positive electrode 4 _P , a negative electrode 4 _N , a separator 20 interposed therebetween, and an electrolytic solution 21. Each of the positive electrode 4 _P and the negative electrode 4 _N includes an active material 40. At the time of discharging, as shown in FIG. 2, lithium is released from the negative electrode 4 _N and moves to the positive electrode 4 _P through the separator 20. At this time, electrons flow from the negative electrode 4 _N and the positive electrode 4 _P receives the electrons. As shown in FIG. 2, when the charging rate SOC is high, the negative electrode 4 _N has a higher lithium concentration than the positive electrode 4 _P.

At the time of charging, as shown in FIG. 3, lithium is released from the positive electrode 4 _P and passes through the separator 20 to the negative electrode 4 _N. At this time, electrons flow from the positive electrode 4 _P and the negative electrode 4 _N receives the electrons. As shown in FIG. 3, when the SOC is low, towards the positive electrode 4 _P lithium concentration is higher than the negative electrode 4 _N.

As shown in FIG. 4, the active material 40 _N constituting the negative electrode 4 _N has a potential gradient of approximately 0 in the low gradient region A _L. In this embodiment, lithium titanate is used as the active material 40 _N of the negative electrode 4 _N. When the storage battery 2 is used, the control unit 3 performs control so that the charging rate SOC becomes the low gradient charging rate SOC _L.

When the storage battery 2 is charged and discharged with a large current, the lithium concentration in the active materials 40 _P and 40 _N varies as shown in FIGS. 5 and 6 while charging and discharging are repeated. Therefore, variation in the charging rate SOC occurs in the storage battery 2. As described above, since the low gradient region A _L in potential gradient is small, less likely to occur high potential difference between the lower part and the lithium concentration is high sites. Therefore, it is difficult for a force to move lithium atoms so as to reduce the potential difference, and it is difficult to reduce concentration variation. In this embodiment, therefore, when the variation of the lithium concentration occurs, that is, when the reversible characteristic deterioration occurs in the storage battery 2, the charging rate SOC to high gradient charge SOC _H, and to recover the battery 2.

  As shown in FIG. 9, the reversible characteristic deterioration is more likely to occur as the temperature T is lower. That is, when the temperature T is lowered, it becomes difficult for lithium to move in the electrode 4, so that variation in lithium concentration is difficult to reduce. When the temperature T increases, lithium easily moves in the electrode 4, so that variation in lithium concentration is easily reduced. That is, reversible characteristic deterioration is easy to recover. However, when the temperature T becomes too high, the electrolytic solution 21 and the like are easily decomposed. That is, irreversible characteristic deterioration is likely to occur.

Next, the flowchart of the control unit 2 will be described. As shown in FIG. 7, the control unit 2 first performs step S1. Here, it is determined whether or not there is an instruction to perform the recovery process. If it is determined YES, the process proceeds to step S2. In step S2, the target value of the charging rate SOC is changed from the low gradient charging rate SOC _L to the high gradient charging rate SOC _H.

Next, the process proceeds to step S3. Here, by charging or discharging the battery 2, the charging rate SOC to high gradient charging rate SOC _H. Thereafter, the process proceeds to step S4. Here, it is determined whether or not a certain time has elapsed. That is, in step S4, the predetermined time left in a state where the storage battery 2 to a high-gradient charging rate SOC _H. If it does in this way, lithium will fully move the inside of the electrode 4, and the characteristic deterioration of the storage battery 2 can be recovered.

Thereafter, the process proceeds to step S5. Here, the target value of the charging rate SOC, returning from the high gradient charging rate SOC _H to the low gradient charging rate SOC _L. Then, the process proceeds to step S6. In step S6, it is charged or discharged the battery 2, the charging rate SOC in the low gradient charging rate SOC _L.

Next, a flowchart for determining whether or not to perform the recovery process, that is, a flowchart for performing step S1 in FIG. 7 will be described with reference to FIG. When making the above determination, as shown in FIG. 8, the controller 3 first performs step S7. Here, the charge / discharge amount It is measured. That is, when the storage battery 2 is charged or discharged, the current I is measured using the current sensor 5 _I (see FIG. 1), and the value of the current I is multiplied by the time t when the current I flows. Thereby, the amount of electric charge moved when the storage battery 2 is charged / discharged (that is, the charge / discharge amount It) is calculated.

Next, the process proceeds to step S8. Here, the charge / discharge amount It is integrated. Then, the process proceeds to step S9. Here, it is determined whether or not the integrated value ΣIt of the charge / discharge amount It exceeds a predetermined threshold value H _TH . If NO is determined here, the process returns to step S7. If YES is determined, the process returns to step S10 to issue an instruction to perform recovery processing. Then, the process proceeds to step S11, and the integrated value ΣIt is reset.

  When the storage battery 2 is repeatedly charged and discharged, the concentration variation of lithium in the electrode 4 gradually increases and reversible characteristic deterioration is likely to occur. Therefore, if the integrated value ΣIt of the charge / discharge amount It is used as an index, it can be determined whether or not reversible characteristic deterioration of the storage battery 2 has occurred.

Next, the effect of this form is demonstrated. The control unit 3 of the present embodiment is configured to perform the recovery process. In this recovery process, control the charging and discharging of the storage battery 2, to change the charging rate SOC of the low gradient charging rate SOC _L to a high-gradient charging rate SOC _H.
In this way, the active material 40 can be moved from the low gradient region A _L to the high gradient region A _H. In the high gradient region A _H , the potential gradient is higher than that in the low gradient region A _L (see FIG. 4). Therefore, a large potential difference is generated between a portion where the concentration of metal atoms (that is, lithium) in the active material 40 is high and a portion where the concentration is low. Therefore, the metal atoms move in the electrode 4 so as to reduce this potential difference, and the concentration variation is reduced. Therefore, reversible characteristic deterioration of the storage battery 2 can be recovered.

The control unit 3 of this embodiment, in use of the storage battery 2 is controlled to a charge rate SOC in the low gradient charging rate SOC _L. As shown in FIG. 7, the control unit 3 performs a recovery process to change the charging rate SOC to the high gradient charging rate SOC _H (steps S2 to S4), and then returns the charging rate SOC to the low gradient charging rate SOC _L (step S2). S5, S6).
For a long time left to the storage battery 2 to a high-gradient charging rate SOC _H, electrolyte 21 is a problem arises such decomposed, there is a possibility that the irreversible characteristic deterioration may occur. As in the present embodiment, after the high-gradient charging rate SOC _H, by returning to the low gradient charging rate SOC _L, it is possible to suppress the irreversible characteristic deterioration of the battery 2. Further, if the battery 2 to a low gradient charging rate SOC _L, then when using a battery 2 can be started immediately used.

Further, the reversible characteristic deterioration of the storage battery 2 is caused by the bias of metal atoms in the active material 40.
The bias of the metal atoms in the active material 40 is because if the active material 40 is changed from the low gradient region A _L to the high gradient region A _H , a high potential difference is generated between a portion having a high concentration of metal atoms and a portion having a low concentration. Can be made uniform easily. That is, reversible characteristic deterioration can be easily recovered.

Moreover, the control part 3 of this form is provided with the integrating | accumulating part 30 (refer FIG. 1) which accumulate | stores the charge / discharge amount It of the storage battery 2 in the past. Control unit 3, when the integrated value ΣIt of the charge and discharge amount It exceeds the value H _TH predetermined, and is configured to perform a recovery process.
When charging and discharging are repeated, the concentration variation of metal atoms in the active material 40 gradually increases. Therefore, if it is determined whether or not the integrated value ΣIt of the charge / discharge amount It exceeds the threshold value H _TH , it is easy to determine whether or not the reversible characteristic deterioration of the storage battery 2 has occurred, that is, whether or not the recovery process should be performed. Can be judged.

In addition, the storage battery 2 of the present embodiment is configured such that metal atoms are removed and inserted into the active material 40 along with charge / discharge.
Such a storage battery 2 is likely to have a large concentration variation of metal atoms in the active material 40 when charged and discharged with a large current. That is, reversible characteristic deterioration is likely to occur. Therefore, as in the present embodiment, the effect of performing the process for recovering the characteristic deterioration is great.

Moreover, the storage battery 2 of this embodiment is a lithium ion secondary battery.
Lithium ion secondary batteries tend to have particularly large variations in lithium atom concentration in the active material 40 when charged and discharged with a large current. Therefore, as in the present embodiment, the effect of performing the process for recovering the characteristic deterioration is great.

Further, in this embodiment, it is used an active material 40 that lithium and a two-phase coexisting react at the low gradient region A _L.
When an active material 40 that causes a two-phase coexistence reaction with lithium is used, the potential gradient tends to be flat (see FIG. 4). For this reason, the output voltage is unlikely to change even when charging and discharging are performed. However, since the active material 40 has a small potential gradient, a large potential difference is unlikely to occur between a portion having a high lithium concentration and a portion having a low lithium concentration. Therefore, variation in lithium concentration is not reduced, and reversible characteristic deterioration of the storage battery 2 is likely to occur. Therefore, as in the present embodiment, the effect of performing the process of recovering the characteristic deterioration is great.

In this embodiment, lithium titanate is used as the active material 40 (40 _N ) having the high gradient region A _H and the low gradient region A _L.
Lithium titanate, potential gradient in the low gradient region A _L is particularly small. Therefore, the effect when this embodiment is applied is particularly great.

  In this embodiment, lithium titanate is used as the active material 40, but the present invention is not limited to this. That is, for example, a phosphate compound having an olivine structure or graphite can also be used.

Further, in the present embodiment, the active material 40 having only the negative electrode 4 _N of the positive electrode 4 _P and the negative electrode 4 _N and having two regions A _L and A _H and causing reversible characteristic deterioration is used. However, the present invention is not limited to this. That is, the positive electrode 4 _P, may be used such active material 40 may be used on both the positive electrode 4 _P and the negative electrode 4 _N.

  As described above, according to this embodiment, it is possible to provide a power supply system that can recover reversible characteristic deterioration of a storage battery.

  Note that whether or not the storage battery 2 has a variation in the charge rate SOC, which is a reversible characteristic deterioration factor, can be confirmed using XAFS, XANES, EXAFS, or the like.

  In the following embodiments, the same reference numerals used in the drawings among the reference numerals used in the drawings represent the same constituent elements as those in the first embodiment unless otherwise indicated.

(Embodiment 2)
This embodiment is an example in which the flowchart for determining whether or not to perform recovery processing is changed. As shown in FIG. 11, in this embodiment, step S21 is first performed. Here, the charge / discharge amount It, the resistance R of the storage battery 2, and the temperature T of the storage battery 2 when charging / discharging are measured. The charge / discharge amount It is the amount of charge moved when the storage battery 2 is charged / discharged, as in the first embodiment. The resistance R is an electrical resistance (that is, an internal resistance) between the positive electrode 4 _P and the negative electrode 4 _N when the storage battery 2 is charged / discharged. The resistance R can be calculated by measuring the voltage V and current I between the electrodes 4 _P and 4 _N using a voltage sensor 5 _V (see FIG. 1) and a current sensor 5 _I, and using the following equation.
R = V / I

  As shown in FIG. 11, after performing step S21, the process proceeds to step S22. Here, the charge / discharge amount It is corrected using the resistance R and the temperature T, and the correction value It × R (T) is integrated. This integration is performed by the integration unit 30 (see FIG. 1). After step S22, the process proceeds to step S23.

In step S23, it is determined whether or not the correction value integrated value Σ (It × R (T)) exceeds a predetermined threshold value H _TH . If NO is determined here, the process returns to step S21. If the determination is Yes, the process proceeds to step S24, and an instruction to perform a recovery process is issued. Thereafter, the integrated value is reset.

The effect of this form is demonstrated. As described above, it is possible to accurately determine whether or not the recovery process should be performed. That is, if charging / discharging is performed when the resistance R is high, current is forced to flow, and reversible characteristic deterioration is likely to occur in the storage battery 2. Therefore, if the charge / discharge amount It is multiplied by the resistance R and it is determined whether the integrated value exceeds the threshold value H _TH , it is possible to more accurately determine whether reversible characteristic degradation has occurred. . Since the resistance R has temperature dependence, in this embodiment, the resistance R is corrected by the temperature T, and the charge / discharge amount It is multiplied by the corrected value R (T).
In addition, the same configuration and operational effects as those of the first embodiment are provided.

(Embodiment 3)
This embodiment is an example in which the configuration of the control unit 3 is changed. When charging / discharging of the storage battery 2 is started and the current I is supplied, the voltage V between the electrodes 4 _P and 4 _N changes as shown in FIG. As shown in the figure, the voltage V can be classified into _a first voltage ΔV _a , a second voltage ΔV _b, and a third voltage ΔV _c . The first voltage ΔVa is due to parasitic and resistance R _a wiring or the like. That is, the current I flows through the wiring and the like, and a potential difference (= R _a I) is generated. This potential difference is the first voltage ΔV _a . The first voltage [Delta] V _a, since due to the resistance R _a of the wiring or the like, after the start of charging and discharging, increases in a short time. For example, the potential difference 0.1 seconds after the start of charge / discharge can be measured as the first voltage ΔV _a . Using this first voltage ΔV _a , the wiring resistance R _a can be calculated from the following equation.
R _a = ΔV _a / I

The second voltage ΔV _b is a voltage resulting from the current I generated by the movement of lithium (metal atom) in the active material 40. It takes about several seconds for lithium to move through the active material 40. Therefore, for example, after starting charging / discharging, the potential difference after 1 second can be measured as the second voltage ΔV _b . From the second voltage ΔVb and the current I, the resistance R _b (= ΔV _b / I) of the active material 40 can be calculated.

The third voltage ΔV _c is a voltage resulting from the movement of the current I by the movement of lithium in the electrolytic solution. It takes about several seconds to several tens of seconds for lithium to move through the electrolyte. Therefore, for example, the potential difference 10 seconds after the start of charge / discharge can be measured as the third voltage ΔV _c . From the third voltage ΔV _c and the current I, the resistance R _c (= ΔV _c / I) of the electrolytic solution can be calculated.

Next, the flowchart at the time of determining whether the recovery process of the storage battery 2 should be performed is demonstrated. As shown in FIG. 13, the control unit 3 first performs step S31. Here, measurement and discharge amount It, and the wiring resistance R _a, the active material resistance R _b, an electrolyte resistance R _c, and a temperature T.

Thereafter, the process proceeds to step S32. Here, the charge / discharge amount It is corrected using the resistances R _a , R _b , R _c and the temperature T, and the correction value It × (R _a (T) + R _b (T) + R _c (T)) is obtained. Accumulate. At the time of correction, the correction coefficient according to the temperature T is changed for each of the resistors R _a , R _b , and R _c .

After performing Step S32, the process proceeds to Step S33. Here, it is determined whether or not the integrated value Σ {It × (R _a (T) + R _b (T) + R _c (T))} exceeds a predetermined value H _TH . If NO is determined here, the process returns to step S31. If YES is determined, the process proceeds to step S34. In step S34, an instruction to perform recovery processing is issued. Thereafter, the process proceeds to step S35, and the integrated value is reset.

The effect of this form is demonstrated. In this embodiment, the resistance R of the storage battery 2 is divided into _a wiring resistance R _a , an active material resistance R _b, and an electrolyte resistance R _c, and these resistances R _a , R _b , R _c are corrected by the temperature T, respectively. Yes.
In this way, it is possible to accurately determine whether or not the recovery process needs to be performed. That is, the resistors R _a , R _b , and R _c have different temperature dependencies. Therefore, if the resistance R is divided into three (R _a , R _b , R _c ) and measured, the resistances R _a , R _b , R _c can be corrected separately according to the temperature T. Therefore, the charge / discharge amount It can be accurately corrected by using the resistors R _a (T), R _b (T), and R _c (T) subjected to temperature correction, and the integrated value of the correction values sets the threshold value H _TH . When it exceeds, it can be accurately determined that the recovery process needs to be performed.
In addition, the same configuration and operational effects as those of the first embodiment are provided.

(Embodiment 4)
This embodiment is an example in which the flowchart for determining whether or not to perform recovery processing is changed. As shown in FIG. 14, the control unit 3 of the present embodiment first performs step S41. Here, charge / discharge amount It, resistance R, and temperature T are measured.

Thereafter, the process proceeds to step S42. Here, the measured temperature T is corrected using the following equation.
T '= T + VI / C
In the above formula, VI is the calorific value of the storage battery 2, and C is the heat capacity of the storage battery 2. Since the temperature sensor 5 _T (see FIG. 1) is attached to the outer surface of the storage battery 2, the temperature inside the storage battery 2 cannot be accurately measured by the temperature sensor 5 _T. Therefore, in this embodiment, the measured temperature T is corrected using the above formula, and the temperature inside the storage battery 2 (corrected temperature T ′) is calculated.

After step S42, the process proceeds to step S43. Here, the charge / discharge amount It is corrected using the resistance R and the corrected temperature T ′, and the correction value It × R (T ′) is integrated. Thereafter, the process proceeds to step S44. Here, it is determined whether or not the integrated value Σ (It × R (T ′)) of the correction value exceeds the threshold value H _TH . If NO is determined here, the process returns to step S41. If YES is determined, the process proceeds to step S45, and an instruction to perform recovery processing is issued. Thereafter, the process proceeds to step S46, and the integrated value is reset.

The effect of this form is demonstrated. In this embodiment, the temperature _T measured by the temperature sensor 5 _T is corrected, and the charge / discharge amount It is corrected using the correction value T ′ and the resistance R. Therefore, the charge / discharge amount It can be accurately corrected, and when the integrated value of the correction value exceeds the threshold value _HTH , it can be accurately determined that the recovery process needs to be performed.
In addition, the same configuration and operational effects as those of the first embodiment are provided.

(Embodiment 5)
This embodiment is an example in which the flowchart of the control unit 3 is changed. As shown in FIG. 15, in this embodiment, step S51 is first performed. Here, it is determined whether or not a predetermined time t _TH has elapsed since the previous recovery process. If YES is determined here, the process proceeds to step S52 to issue an instruction to perform recovery processing.

The effect of this form is demonstrated. With the above configuration, the recovery process can be performed when a predetermined time t _TH has elapsed. Therefore, it is possible to easily determine whether or not to perform recovery processing.
In addition, the same configuration and operational effects as those of the first embodiment are provided.

(Embodiment 6)
This embodiment is an example in which the flowchart of the control unit 3 is changed. As shown in FIG. 16, in this embodiment, step S61 is first performed. Here, the resistance R and the capacity Q of the storage battery 2 are measured. The capacity Q can be calculated using, for example, a time t and a current value I until charging starts from a state in which the storage battery 2 is completely discharged and the battery 2 is fully charged.

After step S61, the process proceeds to step S62. Here, the resistance deterioration rate r and the capacity deterioration rate q are calculated. These values can be calculated by the following method. That is, the initial value R _O of the resistance R of the storage battery 2 and the initial value Q _O of the capacity Q are stored in the control unit 3. In step S61, the deteriorated resistance R and capacitance Q are measured, and the deterioration rates r and q are calculated using the following equations.
r = R / R _O
q = Q / Q _O

  The resistance deterioration rate r is a value reflecting the increase rate of the internal resistance of the storage battery 2, and its contribution to reversible characteristic deterioration is relatively small. The capacity deterioration rate q is a value reflecting that the capacity Q of the entire storage battery 2 has deteriorated, and has a relatively large contribution to reversible characteristic deterioration. Therefore, by determining whether r / q is equal to or less than the threshold value, it is possible to determine whether reversible characteristic degradation has occurred.

  In this embodiment, after performing step S62, the process proceeds to step S63, where it is determined whether r / q is equal to or less than a threshold value. If NO is determined here, the process returns to step S61. If YES is determined, the process proceeds to step S64 to issue an instruction to perform recovery processing.

The effect of this form is demonstrated. In this embodiment, it is determined whether or not reversible characteristic deterioration of the storage battery 2 has occurred using r / q. The resistance deterioration rate r and the capacity deterioration rate q are values that react sensitively to reversible characteristic deterioration. Further, the contribution rates of the respective deterioration rates r and q with respect to the reversible characteristic deterioration of the storage battery 2 are different from each other. Therefore, by using r / q, it is possible to accurately determine whether or not reversible characteristic deterioration has occurred.
In addition, the same configuration and operational effects as those of the first embodiment are provided.

(Embodiment 7)
This embodiment is an example in which the flowchart of the control unit 3 is changed. As shown in FIG. 17, in this embodiment, step S71 is first performed. Here, the deterioration amount H of the storage battery 2 is calculated. The deterioration amount H can be a value obtained by correcting the charge / discharge amount It with the resistance R and the temperature T, for example, as shown in the following equation.
H = It × R (T)

  After performing step S71, the process proceeds to step S72. Here, it is determined whether or not the time differential value dH / dt of the deterioration amount H is equal to or greater than a predetermined threshold value. When the time differential value dH / dt is high, the storage battery 2 is charged and discharged with a large current, and reversible characteristic deterioration is likely to occur. Therefore, by determining whether or not the time differential value dH / dt is equal to or greater than the threshold value, it is possible to accurately determine whether or not reversible characteristic deterioration has occurred in the storage battery 2.

When it is determined No in step S72, the process returns to step S71. If the determination is Yes, the process moves to step S73, and an instruction to perform recovery processing is issued.
In addition, the same configuration and operational effects as those of the first embodiment are provided.

(Embodiment 8)
In this embodiment, the circuit configuration of the power supply system 1 is changed. In this embodiment, as shown in FIG. 18, the power supply system 1 is provided with a recovery instruction unit 6. Recovery instruction unit 6, with the operation of the user, the recovery instruction signal S _R is configured to generate. The recovery instruction unit 6 of this embodiment is a switch. When the user presses the recovery instruction unit 6, the recovery instruction signal S _R is generated.

FIG. 19 shows a flowchart of this embodiment. First, the control unit 3 performs step S81. Here, the recovery instruction signal S _R is determined whether or not the input. If YES is determined here, the process proceeds to step S82 to perform a recovery process.

The effect of this form is demonstrated. With the above configuration, when the user wants to perform the recovery process, the recovery process can be performed at any time by operating the recovery instruction unit 6. Therefore, the reversible characteristic deterioration of the storage battery 2 can be recovered at any time.
In addition, the same configuration and operational effects as those of the first embodiment are provided.

(Embodiment 9)
This embodiment is an example in which the circuit configuration of the power supply system 1 and the control unit 3 are changed. In this embodiment, as in the first embodiment, the power supply system 1 is used in a vehicle. The control unit 3 is configured to perform the recovery process when an instruction to perform the recovery process is given and the ignition switch is turned off.

As shown in FIG. 21, the power supply system 1 of the present embodiment includes a storage battery 2, a control unit 3, a first switch SW <b> 1, and a voltage sensor 5 _V , as in the first embodiment. A power generator 12, a second switch SW 2 and a third switch SW 3, an auxiliary power supply 14, an auxiliary machine 13, and a starter 15 are connected to the power supply system 1. The control unit 3 discharges the storage battery 2 when an instruction to perform a recovery process of the storage battery 2 is given and an ignition switch (not shown) is turned off. The control unit 3 discharges the storage battery 2 when, for example, the user returns home and parks the vehicle at night. That is, the charging rate SOC is changed to substantially 0 (high gradient charging rate SOC _H : see FIG. 4), and the storage battery 2 is recovered. When discharging, the charge stored in the storage battery 2 is transferred to the auxiliary power source 14.

As shown in FIG. 20, the voltage V of the storage battery 2 varies while the vehicle is running (time t _{1 to} t ₂ ) because the storage battery 2 operates an inverter, a motor, and the like. During this period, the charging rate SOC is maintained at a relatively high value. Further, since the storage battery 2 is discharged while the vehicle is stopped (time t _{1 to} t ₂ ), the charging rate SOC and the voltage V become substantially zero.

  Next, the flowchart of the control unit 3 will be described. As shown in FIG. 22, in this embodiment, step S91 is first performed. Here, it is determined whether or not an instruction to perform recovery processing has been issued. If it is determined YES, the process proceeds to step S92.

In step S92, it is determined whether or not the main function of the vehicle has stopped, that is, whether or not the ignition switch has been turned off. If it has been determined that the Yes proceeds to step S93, determines a target voltage V _O. The target voltage V _O can be set to about 1.5 (V), for example.

After step S93, the process proceeds to step S94. Here, the voltage V of the storage battery 2 is measured using the voltage sensor 5 _V (see FIG. 21). Thereafter, the process proceeds to step S95. In this step, it is determined whether or not the voltage V of the storage battery 2 is greater than the target voltage V _O. If YES is determined here, that is, if the voltage V is higher than the target voltage V _O , the process proceeds to step S96 and the storage battery 2 is discharged. Then, the process proceeds to step S97 to determine whether or not a predetermined time has elapsed. Thereafter, the process returns to step S94, and the voltage V is measured again. Further, when it is determined No in step S95, that is, when the voltage V is lower than the target voltage V _O , the process ends. And in the state which discharged the storage battery 2, it waits until a vehicle is started next. Thereby, the reversible characteristic deterioration of the storage battery 2 is recovered.

  The next time the vehicle starts to run, the engine is started using the auxiliary power source 14 and the storage battery 2 is charged using the auxiliary power source 14.

The effect of this form is demonstrated. In the present embodiment, the storage battery 2 can be recovered when an instruction to perform the recovery process of the storage battery 2 is given and the ignition switch is turned off. Therefore, for example, the storage battery 2 can be recovered while the vehicle is parked at night. Therefore, the storage battery 2 can be left discharged for a relatively long time. Therefore, the reversible characteristic deterioration of the storage battery 2 can be sufficiently recovered.
In addition, the same configuration and operational effects as those of the first embodiment are provided.

(Embodiment 10)
This embodiment is an example in which the active material 40 is changed. As shown in FIG. 23, in this embodiment, a high gradient region A _H (hereinafter also referred to as intermediate high gradient region A _HM ) is formed between two low gradient regions A _L1 and A _L2 . Control unit 3, when performing the recovery process of the battery 2, so that the charging rate SOC _HM corresponding to the intermediate high gradient region A _HM, controls the charging and discharging of the battery 2. Thereby, the storage battery 2 is recovered.

The active material 40 can be formed by mixing a plurality of materials. In this embodiment, the low gradient regions A _L1 and A _L2 and the intermediate high gradient region A _HM are formed in the active material 40 _N of the negative electrode 4 _N , but these regions are formed in the active material 40 _P of the positive electrode 4 _P. Can also be formed. Such an active material 40 _P can be manufactured by preparing, for example, a plurality of types of LiMPO ₄ (M is at least one selected from Fe, Mn, Co, and Ni) and mixing them.
In addition, the same configuration and operational effects as those of the first embodiment are provided.

(Embodiment 11)
This embodiment is an example in which the flowchart of the control unit 3 is changed. As shown in FIG. 24, the control unit 3 of the present embodiment first performs step S111. Here, the charging rate SOC of the battery 2, and performs a control to a value near the high gradient charge SOC _H. Thereafter, the process proceeds to step S112. Here, it is determined whether or not an instruction to perform recovery processing has been issued. If it is determined YES, the process proceeds to step S113.

In step S113, the charging rate SOC, control is performed to the high-gradient charging rate SOC _H. Thereafter, the process proceeds to step S114. Here, it is determined whether or not a predetermined time has elapsed. In step S114, the battery 2 a predetermined time, by maintaining the high gradient charging rate SOC _H, to restore reversible characteristic degradation.

The effect of this form is demonstrated. In this embodiment, prior to performing the recovery process, the pre-charging rate SOC, keep the value of the vicinity of the high gradient charging rate SOC _H. Therefore, when performing a recovery process, it is possible to high-gradient charging rate SOC _H immediately charging rate SOC. Therefore, the recovery process can be performed in a short time.
In addition, the same configuration and operational effects as those of the first embodiment are provided.

Embodiment 12
This embodiment is an example in which the flowchart of the control unit 3 is changed. As shown in FIG. 25, the control unit 3 of the present embodiment first performs step S121. Here, it is determined whether or not an instruction to perform recovery processing has been issued. If it is determined YES, the process proceeds to step S122. In step S122, among the plurality of high gradient charging rate SOC _H, selects the closest high gradient charging rate SOC _H to the current charging rate SOC. For example, the current charging rate SOC is (see FIG. 4) 90%, selects 100% as a high gradient charging rate SOC _H. Further, if the current charging rate SOC is 10%, it selects 0% as high gradient charging rate SOC _H.

Thereafter, the process proceeds to step S123. Here, the battery 2 and charge and discharge, the charge rate SOC, control is performed to the high-gradient charging rate SOC _H selected. Then, the process proceeds to step S124, and it is determined whether or not a predetermined time has elapsed. At step S124, the storage battery 2 a predetermined time, by maintaining a high charging rate SOC _H, to restore reversible characteristic degradation of the battery 2.

The function and effect of the present invention will be described. When as described above, the charging rate SOC, it is possible to reduce the discharge amount to the current value in the high gradient charging rate SOC _H. Therefore, power loss can be reduced.
In addition, the same configuration and operational effects as those of the first embodiment are provided.

(Example 13)
This embodiment is an example in which the flowchart of the control unit 3 is changed. As shown in FIG. 26, the control unit 3 of the present embodiment first performs step S131. Here, it is determined whether or not the storage battery 2 is in a recovery preferable use state. For example, it is determined whether or not the vehicle is traveling on a highway. If it is determined YES, the process proceeds to step S132. In this step, the charging rate SOC is changed to a high gradient charging rate SOC _H (for example, 100%).

The effect of this form is demonstrated. When the vehicle is traveling on a highway or the like, since the vehicle is traveling at a constant speed, fluctuations in the charging rate SOC can be reduced. Moreover, this state can be maintained for a relatively long time. Therefore, for example, when the vehicle is traveling on a highway, the storage battery 2 can be stably maintained at a high gradient charge rate SOC _H (for example, 100%) for a long time, and reversible characteristic degradation is efficiently performed. Can be recovered.
In addition, the same configuration and operational effects as those of the first embodiment are provided.

(Embodiment 14)
This embodiment is an example in which the flowchart of the control unit 3 is changed. As shown in FIG. 27, the control unit 3 of the present embodiment first performs step S141. Here, it is determined whether or not the vehicle has approached the planned recovery site. Here, the planned recovery place can be, for example, the user's home. Whether or not the vehicle has approached the planned recovery site can be determined using, for example, a navigation system mounted on the vehicle. Further, when an operation by the user (for example, pressing a switch) is detected, it may be determined that the user has approached the planned recovery site.

If it is determined as Yes in step S141, the process proceeds to step S142. Here, it changes the charging rate SOC to a value close to the high gradient charging rate SOC _H. For example, the storage battery 2 is used to drive a three-phase AC motor or the like, and the charge rate SOC is reduced to near 0%. Thereafter, the process proceeds to step S143. Here, it is determined whether or not the planned recovery place is reached. If YES is determined here, the process proceeds to step S144 to perform a recovery process. That is, the charging rate SOC is set to 0% (that is, the high gradient charging rate SOC _H ), and the system waits until the next use of the vehicle.

The effect of this form is demonstrated. According to the above configuration, since the vehicle heads for the recovery planned area with the state of charge SOC being low, the recovery process can be performed immediately after the arrival at the recovery planned area. In addition, since the charging rate SOC can be reduced by driving a three-phase AC motor or the like while the vehicle is traveling, wasteful discharge can be suppressed.
In addition, the same configuration and operational effects as those of the first embodiment are provided.

(Embodiment 15)
This embodiment is an example in which the flowchart of the control unit 3 is changed. As shown in FIG. 28, the control unit 3 of the present embodiment first performs step S151. Here, it is determined whether or not an instruction to perform recovery processing has been issued. If YES is determined here, the process proceeds to step S152. In step S152, it raises the temperature of the storage battery 2 to a predetermined temperature, and changes the charging rate SOC to high gradient charging rate SOC _H. For example, it may be provided a heater battery 2, while heating the battery 2 by using the heater, to change the charging rate to a high-gradient charging rate SOC _H.

Thereafter, the process proceeds to step S153. Here, it is determined whether or not a certain time has elapsed. In step S153, in a state where the storage battery 2 to a high temperature, a certain time, by maintaining the high gradient charging rate SOC _H, to restore reversible characteristic degradation of the battery 2. When it is determined Yes in step S153, that is, when a certain time has elapsed, the process proceeds to step S154, and the temperature and the charge rate SOC are returned to the original state.

The effect of this form is demonstrated. In this embodiment, when performing a recovery process, at an elevated temperature of the battery 2, and the charging rate SOC to high gradient charging rate SOC _H. If it does in this way, it will become easy to move a metal atom (namely, lithium) in active material 40 by thermal motion, and it will become easy to make concentration variation of a metal atom small. Therefore, the reversible characteristic deterioration of the storage battery 2 can be recovered more efficiently.
In addition, the same configuration and operational effects as those of the first embodiment are provided.

DESCRIPTION OF SYMBOLS 1 Power supply system 2 Storage battery 3 Control part 4 Electrode 4 _P positive electrode 4 _N negative electrode 40 Active material A _H high gradient area A _L low gradient area

Claims (10)

Storage battery (2),
A control unit (3) for controlling charging and discharging of the storage battery,
The storage battery includes a pair of electrodes (4) of a positive electrode (4 _P ) and a negative electrode (4 _N ) each including an active material (40), and constitutes at least one of the pair of electrodes. The active material includes a high gradient region (A _H ) having a relatively high potential gradient, which is a rate of change in potential (V) when the charge rate (SOC) of the storage battery is changed, and the high gradient region And a low gradient region ( _AL ) where the potential gradient is lower than
The storage battery has a reversible characteristic deterioration when the charge rate is a low gradient charge rate (SOC _L ) corresponding to the low gradient region, and the charge rate is a high gradient charge rate corresponding to the high gradient region. (SOC _H ) recovers the above characteristics deterioration,
The control unit is configured to change the charging rate from the low gradient charging rate to the high gradient charging rate by controlling charging / discharging of the storage battery, and to perform a recovery process for recovering the characteristic deterioration. , Power supply system (1).   The storage battery is configured such that metal atoms are inserted into and removed from the active material with charge and discharge, and the reversible characteristic deterioration of the storage battery is caused by the bias of the metal atoms in the active material. The power supply system according to claim 1, wherein   When the storage battery is used, the control unit controls the charging rate to be the low gradient charging rate, performs the recovery process to set the charging rate to the high gradient charging rate, and then sets the charging rate to the above-described charging rate. The power supply system according to claim 1, wherein the power supply system is configured to return to a low gradient charging rate. The control unit includes an integration unit (30) that integrates the charge / discharge amount (It) of the storage battery, and the control unit has a predetermined value (H _TH ) where the integrated value (ΣIt) of the charge / discharge amount is predetermined. The power supply system according to any one of claims 1 to 3, wherein the power recovery system is configured to perform the recovery process when the value exceeds. A resistance measuring unit that measures the resistance (R) between the pair of electrodes, a temperature sensor (5 _T ) that measures the temperature ( _T ) of the storage battery, and the charge value of the storage battery as the resistance value and the temperature. And an integration unit that integrates the correction value (It × R (T)), and the control unit is configured so that the integrated value of the correction value exceeds a predetermined value (H _TH ). The power supply system according to any one of claims 1 to 3, wherein the power supply system is configured to perform the recovery process.   The said storage battery and the said control part are mounted in the vehicle, The said control part is comprised so that the said recovery process may be performed when the ignition switch of the said vehicle is turned off. A power supply system according to any one of the above. A recovery instruction unit (6) that generates a recovery instruction signal (S _R ) in response to a user operation is provided, and the control unit is configured to perform the recovery process when the recovery instruction signal is input. The power supply system according to any one of claims 1 to 6.   The said storage battery is a power supply system as described in any one of Claims 1-7 comprised so that a metal atom may be deinserted in the said active material with charging / discharging.   The power supply system according to claim 8, wherein the storage battery is a lithium ion secondary battery.   The power supply system according to claim 9, wherein the active material that causes a two-phase coexistence reaction with lithium in the low gradient region is used for the storage battery.

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