JP2000035467A - Battery charging device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery charging device, reducing power loss in charging a battery, preventing deterioration of the battery, and capable of surely restoring a memory effect generated in the battery. SOLUTION: An ECU(electric control unit) 30 has a battery-condition detecting means 40 comprising a memory-effect detecting means 42 for detecting generation of a memory effect in a battery 12 and a battery-deterioration detecting means 44 for detecting occurrence of deterioration in the battery 12. Further, the ECU 30 has a memory-effect restoring/charging control part 34 for charging the battery 12 in a memory-effect restoring/charging mode, an under-charging control part 36 for charging the battery 12 in an under-charging mode, and a selection means 38 for selecting the charging mode by switching between an output route of the memory-effect restoring/charging control part 34 and that of the under-charging control part 36, based on a signal from the battery-condition detecting means 40.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery charger for controlling charging of a battery as a power source mounted on an electric vehicle or the like.

[0002]

2. Description of the Related Art Conventionally, when a battery is charged, the SOC (State Of Charg) representing the charge amount of the battery is charged until the battery is fully charged, in other words, the battery is charged.
e: state of charge) until the SOC reached about 100% to 103%.

[0003] However, there is a concern that since charging exceeding the capacity of the battery is performed, charging power at the end of charging is wastefully consumed, and a problem that the battery is liable to deteriorate is likely to occur.

Therefore, charging is not performed until the battery is fully charged. In other words, the SOC of the battery is not charged.
Charge until SOC = about 90% to 95%,
The introduction of a so-called under-charging method is being considered.

[0005]

SUMMARY OF THE INVENTION Incidentally, Ni-MH
It has been confirmed that a memory effect occurs under a predetermined condition in a battery such as a battery using nickel for an electrode. This memory effect is a phenomenon in which the battery capacity after charging is smaller than when the memory effect does not appear, and the output capacity (discharge current amount, unit: Ah) of the battery decreases.

The following two conditions have been confirmed as conditions under which such a memory effect occurs. First
Occurs when charging is performed again when the battery is not sufficiently discharged, and the second occurrence condition is when discharging is performed when the battery is not sufficiently charged.

As a technique for eliminating the memory effect, there is known a so-called reconditioning process in which a battery is completely discharged once by using a discharger at the start of charging, and thereafter charging is started.

However, whether or not to perform the reconditioning process is left to the discretion of the user of the battery. Therefore, by repeating charging and discharging without performing the reconditioning process, the battery based on the memory effect can be obtained. There is a possibility that the amount of discharge current of the battery may decrease.

In addition, when the battery is constantly charged by the above-described under-charging method, the second occurrence condition is satisfied, and the memory effect cannot be eliminated.
There is a problem that the amount of discharge current of the battery decreases.

The present invention has been made in view of such problems, and reduces power loss during battery charging, prevents battery deterioration, and ensures that a memory effect generated in the battery is obtained. It is an object of the present invention to provide a battery charger capable of preventing the output capacity of the battery from lowering.

[0011]

According to the present invention, based on a detection result by a memory effect detecting means for detecting whether a memory effect has occurred in a battery, a charge amount of the battery is set to a first value by a selecting means. The charging process by the first charging control unit that charges the battery until the charging amount is reached, or the charging is performed on the battery until the charging amount of the battery reaches a second charging amount that is smaller than the first charging amount. It is configured such that the charging process by the second charging control means can be selected (the invention according to claim 1).

In this case, when the memory effect does not occur in the battery, the battery is charged in the under charge mode by the second charge control means, so that the charging power is wasted. When the battery has a memory effect, the battery is charged in the memory effect recovery charging mode by the first charge control means, thereby recovering the memory effect. Can be done.

Further, the memory effect detecting means is configured to detect whether or not the battery has a memory effect based on the time change rate of the battery voltage at the time when the charging process for the battery is completed, The occurrence of the memory effect can be accurately detected, and an appropriate charging process can be selected according to the detection result (the invention according to claim 2).

Further, the battery deterioration detecting means is configured to detect whether or not the battery has deteriorated based on the time change rate of the battery voltage at the time of charging a predetermined number of times (for example, several times). And wherein the memory effect detecting means is configured to detect whether or not the battery has a memory effect based on the time change rate of the battery voltage at the time of charging the predetermined number of times before, so that the memory effect is detected. It is possible to distinguish between the case where the deterioration has occurred and the case where the memory effect has occurred, and select an appropriate charging process corresponding to each case (the invention according to claim 3).

Similarly, the memory effect detecting means and the battery deterioration detecting means compare the second predetermined value obtained from the table based on the battery temperature at the start of charging with the time change rate of the battery voltage. By detecting whether a memory effect has occurred or deterioration has occurred in the battery, the battery is not affected by a change in the rate of change of the battery voltage with time due to a change in the battery temperature. It is possible to accurately distinguish the case where the deterioration has occurred and the case where the memory effect has occurred (the invention according to claim 4).

In this case, when the battery deterioration detecting means detects that the battery is deteriorated, the selecting means selects the processing by the second charging control means, so that In this case, it is possible to prevent the memory effect recovery process from being performed when the battery is deteriorated, that is, to prevent the useless charging process from being performed (the invention according to claim 5).

[0017]

An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 shows a configuration of a battery charger 10 to which an embodiment of the present invention is applied.

The battery charger 10 includes a battery 1
2 has a charger 14 for charging. In the charging state, the charger 14 has a charging connector 15
Is connected to an external power supply such as AC100V.

The battery 12 has a battery temperature detecting means (temperature detecting means) 20 for detecting the temperature of the battery 12 (battery temperature Tb), and a battery voltage detecting means for detecting the voltage of the battery 12 (battery voltage Vb). (Voltage detecting means) 22 is connected.

The battery charger 10 includes an ECU (Electr
ic Control Unit) 30. This ECU 30
A CPU serving as a central processing unit, a ROM serving as storage means (memory) for storing a system program, an application program for detecting remaining capacity, and a RAM serving as storage means (memory) used for work or the like; ,
It is composed of a microcomputer including a timer for measuring time (measuring means), an input / output interface of an A / D converter, a D / A converter, and the like.

The ECU 30 is supplied with the battery temperature Tb from the battery temperature detecting means 20 and the battery voltage Vb from the battery voltage detecting means 22. Then, the ECU 30 determines the state of the charger 14 based on these signals.
Control.

Here, the ECU 30 has a battery state detecting means 4 for detecting whether or not the battery 12 is normal.
0 is provided. This battery state detecting means 40
Has a memory effect detecting means 42 for detecting that a memory effect has occurred in the battery 12 and a battery deterioration detecting means 44 for detecting that the battery 12 has deteriorated.

The ECU 30 includes a charge amount integrated value detecting means 24 for calculating the integrated charge amount Ab by integrating the charge amounts for the battery 12 and a charge number detecting means 26 for detecting the charge number n for the battery 12. It is connected. In addition, the charge amount integrated value detecting means 24 is connected to the battery 12.
It is also possible to replace the charge amount with respect to the amount of discharge from the battery 12, in other words, to replace the charge amount integrated value detection means 24 with discharge amount integrated value detection means for obtaining the integrated value of the discharge amount.

In this case, the memory effect detecting means 42 and the battery deterioration detecting means 44 respectively include the battery temperature Tb from the battery temperature detecting means 20, the battery voltage Vb from the battery voltage detecting means 22, and the integrated charge amount. Based on the integrated amount of charge Ab from the detecting means 24 and the number of times of charging n from the number-of-times-of-charging detecting means 26, it is detected that the battery 12 has a memory effect or deterioration.

Further, the ECU 30 includes a memory effect recovery charge control section (first charge control means) 34 for charging the battery 12 in the memory effect recovery charge mode which is a charge mode for performing the memory effect recovery process. An under charge control unit (second charge control unit) 36 for charging the battery 12 in an under charge mode, which is a normal charge mode; the memory effect recovery charge control unit 34; Selection means 38 for selecting a charging mode by switching an output path with the unit 36 is provided. In this case, the selection unit 38 switches the output path based on a signal from the battery state detection unit 40.

In the under charge mode, the state of charge (SOC) of the battery 12 is about 9
Charging is performed from 0% to 95% (second charging state).
Therefore, when charging is performed in the under charge mode, the charging time is shortened and the charging efficiency is increased, but the discharge current amount is reduced. Further, since charging is completed before the battery 12 is fully charged, a memory effect may occur in the battery 12.

On the other hand, in the memory effect recovery charging mode, the SOC of the battery 12 is about 100% to 103%.
Charging is performed up to the (first charging state), in other words, up to the overcharging state. Therefore, when charging is performed in the memory effect recovery charging mode, the memory effect occurring in the battery 12 can be recovered.

Next, control processing mainly related to charge control by the ECU 30 of the battery charger 10 shown in FIG. 1 will be described with reference to flowcharts shown in FIGS. 2 to 5 and FIG.

First, the first processing operation example shown in FIG. 2 will be described.

First, it is detected whether or not a memory effect has occurred in the battery 12 (step S9).
1). Subsequently, the charging mode is selected based on the detection result in step S91 (step S9).
2). Specifically, when the occurrence of the memory effect is detected, the battery 12 is charged in the memory effect recovery charging mode (step S93), and when the occurrence of the memory effect is not detected, the battery 12 is charged. On the other hand, charging in the under charge mode is performed (step S94).

In the flowchart of FIG. 2, the processing in step S91 is performed on the memory effect detecting means 42, the processing in step S92 is performed on the selecting means 38, and the processing in step S93 is performed on the memory effect recovery charging. The process is performed on the control unit 34, and the process of step S94 is performed on the undercharge control unit 36.

As described above, in the first processing operation example, it is detected whether or not the memory effect has occurred in the battery 12, and based on the detection result, the battery 12 is charged in the memory effect recovery charging mode. It is configured to select whether to perform charging in the under charging mode or to perform charging in the under charging mode. For this reason, normally, the power loss during charging can be reduced by selecting the under charge mode, and when the memory effect occurs, the output capacity of the battery 12 can be reduced by selecting the memory effect recovery charge mode. Degradation can be avoided.

Next, a second processing operation example shown in FIG. 3 will be described.

When the charging of the battery 12 is started, the charging mode of the memory effect recovery charging mode or the under charging mode is selected based on the number of chargings performed before the current charging operation (step S1). . Specifically, the number of times of charging n is compared with a predetermined number of times n0. The predetermined number of times n0 is based on the relationship between the number of charges n and the probability of the occurrence of the memory effect when the battery 12 is charged in the under-charge mode, and n is determined as a predetermined value.

Therefore, when the number of times of charging n is larger than the predetermined number of times n0, it is considered that the memory effect has occurred in the battery 12, and the memory effect recovery charging mode is selected. If:
The undercharge mode is selected on the assumption that the battery 12 has no memory effect.

When the memory effect recovery charging mode is selected in step S1, the charging of the battery 12 in the memory effect recovery charging mode is started (step S2).

In this case, first, the number of times of charging n is reset by setting the number of times of charging n to n = 0 (step S3).

Subsequently, it is determined whether the charging is completed (step S4). Specifically, first, a battery temperature change dTb / dt, which is a time change rate of the battery temperature Tb, is obtained, and it is determined whether the battery temperature change dTb / dt is greater than a predetermined value α. Battery temperature change d
When Tb / dt is larger than the predetermined value α, a process of terminating the charging is performed (step S5). On the other hand, when the battery temperature change dTb / dt is equal to or smaller than the predetermined value α, charging is continued.

Here, the determination of the end of charging in the step S4 is made by comparing the battery voltage Vb with a predetermined value Vb0, or by changing the battery temperature Tb to a predetermined value Tb.
It may be performed by comparing with b0 (steps S4 ′, S4 ″).

On the other hand, when the under charge mode is selected in step S1, the battery 12 is started to be charged in the under charge mode (step S1).
6).

In this case, first, 1 is added to the number of charges n (n = n + 1), and the number of charges n is updated (step S7).

Subsequently, the end of charging is determined (step S8). Specifically, first, a battery voltage change dVb / dt, which is a time change rate of the battery voltage Vb, is obtained, and it is determined whether the battery voltage change dVb / dt is greater than a predetermined value β. Battery voltage change d
If Vb / dt is larger than the predetermined value β, a process for terminating charging is performed (step S9). On the other hand, when the battery voltage change dVb / dt is equal to or less than the predetermined value β, charging is continued.

In this case, the end of charging in step S8 may be determined by comparing the battery voltage Vb with a predetermined value Vb0 '.

In the flowchart of FIG. 3, the processing in step S1 is performed on the number-of-times-of-charging detecting means 26, the memory effect detecting means 42, and the selecting means 38, and the processing in step S2 is performed on the memory effect recovery charging control section 34. The processing in step S3 is performed on the number-of-times-of-charging detecting means 26, the processing in step S4 is performed on the ECU 30 and the battery temperature detecting means 20, and the processing in step S5 is performed.
Is performed on the ECU 30. The processing of step S4 'is performed by the ECU 30 and the battery voltage detecting means 2.
2 and the processing of step S4 ″ is performed by the ECU 30
And the battery temperature detecting means 20. Further, the process in step S6 is performed on the under-charge control unit 36, and the process in step S7 is
6, the processing in step S8 is performed on the ECU 30 and the battery voltage detecting means 22, and the processing in step S9 is performed on the ECU 30.

As described above, in the second processing operation example, every time the number of times n of charging the battery 12 in the under charge mode reaches the predetermined number of times n0, the battery 12 is regarded as having a memory effect, and An effect recovery process is performed. For this reason, normally, the power loss during charging can be reduced by selecting the under charge mode, and when the memory effect occurs, the output capacity of the battery 12 can be reduced by selecting the memory effect recovery charge mode. It is possible to reliably avoid the reduction.

Next, a third processing operation example shown in FIG. 4 will be described.

When the charging of the battery 12 is started, a charging mode of the memory effect recovery charging mode or the under charging mode is selected based on the integrated charging amount Ab of the battery 12 (step S11). Specifically, a comparison between the integrated charge amount Ab and a predetermined value Ab0 is performed. The predetermined value Ab0 is the integrated charge amount A when the battery 12 is charged in the under charge mode.
Based on the relationship between b and the probability of the occurrence of the memory effect, the integrated charge amount Ab at which the memory effect occurs in the battery 12 is determined as a predetermined value.

Therefore, if the integrated charge amount Ab is larger than the predetermined value Ab0, it is considered that the memory effect has occurred in the battery 12, and the memory effect recovery charge mode is selected. If Ab0 or less, it is considered that the memory effect has not occurred in the battery 12, and the under charge mode is selected. Here, when the charge amount in step S11 is replaced with the discharge amount,
The charge mode is selected by comparing the integrated value of the discharge amount with the predetermined value Ab0.

When the memory effect recovery charging mode is selected in step S11, charging of the battery 12 in the memory effect recovery charging mode is started (step S12).

In this case, first, the integrated charge amount Ab is calculated as Ab
By setting = 0, the accumulated charge Ab is reset (step S13).

Subsequently, the end of charging is determined (step S14). Here, similarly to step S4 (see FIG. 3) in the second processing operation example, it is determined whether the battery temperature change dTb / dt is larger than a predetermined value α. When the battery temperature change dTb / dt is larger than the predetermined value α, the process of terminating charging is performed (step S1).
5) On the other hand, when the battery temperature change dTb / dt is equal to or less than the predetermined value α, charging is continued.

Further, the determination of the end of charging in the step S14 is made according to the steps S4 ′ and S4 ″ (see FIG. 3).
Similarly, the battery voltage Vb is compared with a predetermined value Vb0, or the battery temperature Tb is set to a predetermined value Tb0.
It may be performed by comparing with 0 (steps S14 ′ and S14 ″).

On the other hand, when the under charge mode is selected in step S11, charging of the battery 12 in the under charge mode is started (step S11).
16).

Next, the charge amount of the battery 12 is integrated, and the integrated charge amount Ab is obtained (step S1).
7).

Subsequently, it is determined that the charging is completed (step S18). Here, similarly to step S8 (see FIG. 3) in the second processing operation example, it is determined whether the battery voltage change dVb / dt is larger than a predetermined value β. Then, when the battery voltage change dVb / dt is larger than the predetermined value β, a process of terminating the charging is performed (step S19). On the other hand, the battery voltage change dVb /
If dt is equal to or smaller than the predetermined value β, the charging is continued, and the processing in step S17 and step S18 is repeatedly performed.

Here, the determination of the end of charging in step S18 may be made by comparing the battery voltage Vb with a predetermined value Vb0 '.

In the flowchart of FIG. 4, the processing in step S11 is performed on the integrated charge amount detecting means 24, the memory effect detecting means 42, and the selecting means 38.
The processing in step S12 is performed by the memory effect recovery charging control unit 34.
The processing in step S13 is performed on the charge amount integrated value detecting means 24, the processing in step S14 is performed on the ECU 30 and the battery temperature detecting means 20, and the processing in step S15 is performed on the ECU 30. Done. The processing in step S14 'is performed on the ECU 30 and the battery voltage detecting means 22, and the processing in step S1' is performed.
The processing of 4 ″ is performed by the ECU 30 and the battery temperature detecting unit 20.
Done for Further, the processing in step S16 is performed on the under-charge control unit 36, and the processing in step S17 is performed.
Is performed on the charged amount integrated value detecting means 24, the processing of step S18 is performed on the ECU 30 and the battery voltage detecting means 22, and the processing of step S19 is performed on the EC.
This is performed for U30.

As described above, in the third processing operation example, every time the integrated value of the charged amount of the battery 12 in the undercharge mode (the integrated charged amount Ab) reaches the predetermined value Ab0,
The memory effect recovery processing is performed on the assumption that the memory effect has occurred in the battery 12. For this reason, normally, the power loss during charging can be reduced by selecting the under charge mode, and when the memory effect occurs, the output capacity of the battery 12 can be reduced by selecting the memory effect recovery charge mode. It is possible to reliably avoid the reduction.

Next, a fourth processing operation example shown in FIG. 5 will be described.

First, charging of the battery 12 in the under charge mode is started (step S31).

Next, based on the battery temperature Tb, a charge termination judgment voltage Ve1 as a reference for judging the termination of the charge when the battery is being charged in the under charge mode is searched from a look-up table or the like (step S32). The look-up table includes a charge end determination voltage Ve1 for the battery temperature Tb and a charge end determination voltage V
e2 is recorded and stored in the ROM of the ECU 30. The reason why the charging end determination voltage Ve1 is determined based on the battery temperature Tb in this manner is that the battery voltage Vb at the time when SOC = 90% to 95% changes with the change in the battery temperature Tb. It is.

Subsequently, it is determined whether charging is completed (step S33). Specifically, a comparison between the battery voltage Vb and the charge end determination voltage Ve1 is performed. If the battery voltage Vb is higher than the charge end determination voltage Ve1, a charge end determination is made, and the battery voltage Vb is When the voltage is equal to or lower than the charge end determination voltage Ve1, it is determined that the charge is to be continued, and the charge is continued.

If it is determined in step S33 that the charging has been completed, the process proceeds to the subsequent step S34. In this step S34, the battery voltage change dVb / dt when the battery voltage Vb reaches the charge end determination voltage Ve1 is determined, and this battery voltage change dVb
/ Dt and a predetermined value (first predetermined value) γ are compared. If the battery voltage change dVb / dt is larger than a predetermined value γ, it is determined that the battery 12 is not normal. If the battery voltage change dVb / dt is not larger than a predetermined value γ, the battery 12 is normal. Is determined.

As described above, the battery voltage change dVb at the time when the battery voltage Vb becomes equal to the charging end determination voltage Ve1
Whether the battery 12 is normal or not is determined based on / dt, as shown in the graph of FIG. 6, when the battery 12 is not normal (when a memory effect or deterioration occurs). The battery voltage change dVb / dt in C1 is the same as the battery voltage change dVb / dt in characteristic example C2 when the battery 12 is normal.
This is because it becomes larger than. In this case, battery 1
In the characteristic example C3 of the judgment level for judging whether or not the battery voltage is normal, the battery voltage change dVb / at the time when the battery voltage Vb becomes the charge end judgment voltage Ve1.
dt is a predetermined value γ.

If it is determined in step S34 that the battery 12 is not normal, a cause of causing the battery 12 to be in an abnormal state is determined (step S4).
1). Specifically, a predetermined number of times since the current charge, for example,
At the time of charging several times before, the battery voltage change dVb '/ dt obtained in step S34 is compared with the predetermined value γ. If the battery voltage change dVb '/ dt is larger than the predetermined value γ, it is determined that the cause of the battery 12 in an abnormal state is deterioration, and the battery voltage change dVb' / dt is equal to or smaller than the predetermined value γ. In this case, it is determined that the cause is a memory effect.

As described above, the battery voltage change dVb '/ dt at the time of charging several times before the current charging and the predetermined value γ
The reason why the abnormal condition of the battery 12 can be determined by comparing with the following is based on the following reason.

As shown in the graph of FIG.
Voltage change d when memory effect occurs
The characteristic of Vb / dt with respect to the number of times of charging (characteristic example C4) has a larger slope than the characteristic when battery 12 is deteriorated (characteristic example C5). This is because the deterioration of the battery 12 occurs more slowly than the memory effect. Further, when the memory effect is generated in the battery 12, the battery effect change dVb / dt temporarily decreases by performing the memory effect recovery process.
When the battery 12 has deteriorated, the battery voltage change dVb / d even when the memory effect recovery process is performed.
t does not decrease. Accordingly, the battery voltage change dVb / dt at the end of charging exceeds the predetermined value γ, and the battery voltage change d at the end of charging at the time of charging a predetermined number of times ago.
If Vb / dt also exceeds the predetermined value γ, the battery 1
2 can be determined to be degraded. In this case, the predetermined number of times may be one time or several times (for example, five or six times).

In step S41, the battery 1
When it is determined that deterioration has occurred in No. 2, a warning of deterioration is issued by a not-shown warning means (step S <b> 4).
2) Then, a process of ending charging is performed (step S).
43).

On the other hand, when it is determined in step S41 that a memory effect has occurred in the battery 12, it is determined whether or not it is necessary to perform a memory effect recovery process (step S51). Here, the second
Similarly to the processing in step S1 (see FIG. 3) in the processing operation example, the number of times of charging n before the current charging operation is compared with the predetermined number of times n0, and when the number of times of charging n is larger than the predetermined number of times n0 It is determined that the memory effect recovery process needs to be performed, and when the number of times of charging n is equal to or less than the predetermined number of times n0, it is determined that the memory effect recovery process does not need to be performed. In this case, the predetermined number n0 is n0 =
About 20 times. As described above, the charging number n is equal to the predetermined number n.
When the value is 0 or less, the reason why the memory effect recovery processing is not performed is to prevent unnecessary consumption of charging power and deterioration of the battery due to performing the memory effect recovery processing more than necessary.

If it is determined in step S51 that the memory effect recovery processing needs to be performed, charging of the battery 12 in the memory effect recovery charging mode is started (step S52).

Next, based on the battery temperature Tb, a look-up table or the like is used to search for a charge termination determination voltage Ve2, which is a criterion for termination of charging when charging is performed in the memory effect recovery charging mode (step S5).
3). In this case, the charge end determination voltage Ve2 is determined by SOC =
Battery voltage Vb at the time when it becomes approximately 100% to 103%
Is equivalent to

Subsequently, the end of charging is determined (step S54). Specifically, a comparison between the battery voltage Vb and the charge end determination voltage Ve2 is performed, and when the battery voltage Vb is higher than the charge end determination voltage Ve2, a charge end determination is made. When the voltage is equal to or lower than the charge end determination voltage Ve2, it is determined that the charge is to be continued, and the charge is continued.

If it is determined in step S54 that charging has been completed, the number of times of charging n is set to n, as in step S3 (see FIG. 3) in the second processing operation example.
By setting = 0, the number of times of charging n is reset (step S55), and then a process of terminating the charging is performed (step S43).

If it is determined in step S51 that it is not necessary to perform the memory effect recovery process, the second
In the same manner as the processing of step S7 (see FIG. 3) in the processing operation example, 1 is added to the number of times of charging n (n = n + 1).
The number of times of charging n is updated (step S56), and then the process of terminating the charging is performed (step S4).
3).

Also, when it is determined in step S34 that the battery 12 is normal, similarly, 1 is added to the number of charges n (n = n + 1), and the number of charges n
Is updated (the above-mentioned step S56), and then a process of terminating the charging is performed (the above-mentioned step S43).

Incidentally, in step S41, FIG.
From the table 50 shown in FIG.
A predetermined value (a second predetermined value) ε is obtained based on b, and the predetermined value ε is compared with the battery voltage change dVb / dt obtained in step S34 to determine the cause. (Step S41 ').

This table 50 records, as a predetermined value ε, a change in battery voltage dVb / dt at the end of charging with respect to the battery temperature Tb at the start of charging at the time of past charging. Therefore, the battery temperature Tb similar to the battery temperature Tb obtained in step S32
Is retrieved from the table 50 to obtain the predetermined value ε. For example, when Tb = 22 ° C., ε5 which is a predetermined value ε when Tb = 20 ° C. is obtained. If the difference between the battery voltage change dVb / dt obtained in step S34 and the predetermined value ε exceeds a predetermined value ζ, it is determined that the battery 12 has deteriorated.

In the flowchart of FIG. 5, the process of step S31 is performed on the selection means 38 and the under-charge control unit 36, and the process of step S32 is
This processing is performed on the battery temperature detecting means 20 and the ECU 30.
2 and the ECU 30, the processing in step S34 is performed on the battery state detecting means 40, and the processing in step S41 is performed on the memory effect detecting means 42 and the battery deterioration detecting means 44. S42
Is performed for a warning unit (not shown), and the process of step S43 is performed for the ECU 30. The processing in step S51 is performed on the number-of-times-of-charging detecting means 26 and the selecting means 38, the processing in step S52 is performed on the memory effect recovery charging control section 34, and the processing in step S53 is performed on the battery temperature. The detection is performed on the detection means 20 and the ECU 30.
The processing is performed on the battery voltage detecting means 22 and the ECU 30, and the processing of steps S 55 and S 56 is performed on the charging number detecting means 26. Further, step S41 ′
The processing of (S71 ') is performed on the ECU 30 and the table 50.

As described above, in the fourth processing operation example, when the battery voltage change dVb / dt at the end of charging the battery 12 in the under-charge mode is larger than the predetermined value γ, the battery 12 has a memory effect or the like. Since it is determined that the cause of the abnormal state has occurred, it is possible to reliably detect the occurrence of the abnormal state. Therefore, due to the effect of the memory effect, the battery 1
2 can be more reliably prevented from being reduced.

The determination as to whether the cause of the abnormal state of the battery 12 is a memory effect or deterioration is made a predetermined number of times from the current charge, for example, the battery voltage change dVb '/ at the time of the charge several times before. Since the determination is made based on dt, the determination can be made reliably.
In this case, when the memory effect is generated in the battery 12, the memory effect recovery process is performed, and when the battery 12 is deteriorated, the memory effect recovery process is not performed. It is possible to prevent the charging time and the charging cost from being increased by performing an appropriate process.

Further, a change in battery voltage dVb / dt at the end of charging with respect to the battery temperature Tb at the start of charging in the past charging is recorded in the table 50 as a predetermined value ε. A predetermined value ε is searched for based on the battery temperature Tb at the start time, and the predetermined value ε is compared with the battery voltage change dVb / dt at the end of charging at the time of the current charging, whereby the abnormal state of the battery 12 is determined. It can be determined whether the cause is a memory effect or deterioration. In this case, the value of the battery voltage change dVb / dt is not affected by the change in the battery temperature Tb, and it is determined whether the cause of the abnormal state of the battery 12 is a memory effect or deterioration. Can be performed more reliably.

Next, a fifth processing operation example shown in FIG. 9 will be described.

First, a flag (memory effect flag) determined in step S75 or S85 described later.
Based on whether F is 1 or 0, it is determined whether or not it is necessary to perform a process for restoring the memory effect (step S61). Here, it is assumed that when F = 1, processing for restoring the memory effect needs to be performed, and when F = 0, processing for restoring the memory effect need not be performed.

If it is determined in step S61 that F = 0 and it is not necessary to perform the process for restoring the memory effect, the battery 12 is charged in the under-charge mode. Here, the same processing as the processing of steps S31 to S33 and S43 (see FIG. 5) in the fourth processing operation example is performed. That is, when charging in the under charge mode is started (step S62),
The charging end determination voltage Ve1 is searched based on the battery temperature Tb (step S63). Then, when the battery voltage Vb exceeds the charge end determination voltage Ve1, the charge end is determined (step S64), and the charge end process is performed (step S65).

Subsequently, similar to the processing in step S34 (see FIG. 5) in the fourth processing operation example, the battery 1
2 is determined as normal or abnormal (step S6).
6). That is, the battery voltage Vb becomes equal to the charging end determination voltage Ve.
1 is compared with a predetermined value γ, and the battery voltage change dVb / dt is compared with the predetermined value γ.
If / dt is larger than the predetermined value γ, it is determined that the battery 12 is not normal, and the battery voltage change dVb /
If dt is equal to or smaller than the predetermined value γ, it is determined that the battery 12 is normal.

If it is determined in step S66 that the battery 12 is not normal, as in the case of step S41 (see FIG. 5) in the fourth processing operation example, the cause of the battery 12 being brought into an abnormal state may be determined. A determination is made (step S71). That is, the battery voltage change dVb '/ dt obtained in step S66 is compared with the predetermined value γ at the time of charging several times before the current charging, and the battery voltage change dVb' / dt is compared with the predetermined value γ. If it is larger, the battery deterioration detecting means 44
It is determined that the cause of abnormal state 2 is deterioration,
If the battery voltage change dVb '/ dt is equal to or smaller than the predetermined value γ, the memory effect detecting means 42 determines that the cause is the memory effect.

Here, a predetermined value ε is obtained from the table 50 shown in FIG. 8 based on the battery temperature Tb at the start of charging, and this predetermined value ε is compared with the battery voltage change dVb / dt at the end of charging. This may be used to determine the cause (step S7 in FIG. 5).
1 ').

In step S71, the battery 1
When it is determined that deterioration has occurred in the second processing operation, a warning of deterioration is issued (step S72), similarly to the processing in step S42 (see FIG. 5) in the fourth processing operation example, and a series of processing ends. Is done.

On the other hand, if it is determined in step S71 that a memory effect has occurred in the battery 12, the number of times of charging is n, as in step S56 (see FIG. 5) in the fourth processing operation example. Is added to (n = n + 1), and the number of times of charging n is updated (step S73).

Subsequently, similarly to the processing in step S51 (see FIG. 5) in the fourth processing operation example, it is determined whether or not the memory effect recovery processing needs to be performed (step S74). That is, the number of times of charging n before the current charging operation is compared with a predetermined number of times n0 (n0 = about 20 times). If the number of times of charging n is larger than the predetermined number of times n0, it is necessary to perform a memory effect recovery process. When the number of times of charging n is equal to or less than the predetermined number of times n0, it is determined that there is no need to perform the memory effect recovery process.

If it is determined in step S74 that the memory effect recovery processing needs to be performed, the flag F
Is set to F = 1 (step S75). On the other hand, if it is determined in step S74 that the memory effect recovery processing does not need to be performed, a series of processing ends.

If it is determined in step S66 that the battery 12 is normal, 1 is added to the number of times of charging n (n = n + 1), as in the process of step S73, and the number of times of charging n is reduced. It is updated (step S76).

If it is determined in step S61 that F = 1 and it is necessary to perform the process for restoring the memory effect, the battery 12 is charged in the memory effect restoration charging mode. Here, first, the fourth
Steps S52 to S54 and S4 in the processing operation example of
3 (see FIG. 5). That is,
When charging in the memory effect recovery charging mode is started (step S81), a charge termination determination voltage Ve2 is searched from a look-up table or the like based on the battery temperature Tb (step S82). Then, when the battery voltage Vb exceeds the charge end determination voltage Ve2, the charge end is determined (step S83), and the charge end process is performed (step S84).

Subsequently, the flag F is set to F = 0 (step S85), and similarly to the processing of step S55 (see FIG. 5) in the fourth processing operation example, the number of times of charging by the charging number detecting means 26 is determined. By setting n to n = 0, the number-of-charges detecting means 26 is reset (step S86).

In the flowchart of FIG. 9, the process of step S61 is performed on the ECU 30 and the selection means 38, the process of step S62 is performed on the undercharge control unit 36, and the process of step S63 is performed on the undercharge control unit 36. ,
The processing is performed on the battery temperature detecting means 20 and the ECU 30.
2 and the ECU 30; the processing of steps S65 and S66 is performed on the ECU 30; the processing of step S71 is performed on the memory effect detecting means 42 and the battery deterioration detecting means 44; The process is performed on the ECU 30. The process of step S73 is performed on the number-of-times-of-charge detection unit 26. The process of step S74 is performed on the number-of-times-of-charge detection unit 26 and the ECU 30.
The processing of step S75 is performed by the ECU 30
, And the process of step S76 is performed on the number-of-times-of-charging detecting means 26. Further, the process of step S81 is performed on the memory effect recovery charge control unit 34, and the process of step S82 is performed on the battery temperature detecting unit 2
0 and the ECU 30. The processing of step S83 is performed on the battery voltage detecting means 22 and the ECU 30. The processing of steps S84 and S85 is performed by the ECU
30, and the process of step S86 is performed on the number-of-times-of-charging detecting means 26.

As described above, in the fifth processing operation example, when starting charging, the flag F is set to indicate whether the battery 12 should be charged in the under-charge mode or in the memory effect recovery charge mode. The selection is based on In this case, since the process of restoring the memory effect can be performed at the same time as charging the battery 12,
The charging time can be reduced and the charging cost can be reduced.

[0098] The present invention is not limited to the above-described embodiment, but may adopt various configurations without departing from the spirit of the present invention.

[0099]

According to the first aspect of the present invention, it is possible to avoid unnecessary consumption of charging power and to recover the memory effect generated in the battery.

According to the second aspect of the present invention, the occurrence of the memory effect can be accurately detected, and an appropriate charging process can be selected according to the detection result.

According to the third aspect of the present invention, it is possible to distinguish between a case where the battery has deteriorated and a case where the memory effect has occurred, and select an appropriate charging process corresponding to each case.

According to the fourth aspect of the present invention, the battery is not affected by the change in the time change rate of the battery voltage due to the change in the battery temperature. Can be distinguished accurately.

According to the fifth aspect of the invention, it is possible to prevent the memory effect recovery process, which is a useless charging process, from being performed when the battery is deteriorated.

Therefore, according to the first to fifth aspects of the present invention, it is possible to reduce the power loss at the time of charging the battery, prevent the battery from deteriorating, and reliably recover the memory effect generated in the battery. It is possible to prevent the output capacity of the battery from decreasing.

[Brief description of the drawings]

FIG. 1 is a block diagram illustrating a configuration of a battery charging device.

FIG. 2 is a flowchart illustrating a first processing operation example;

FIG. 3 is a flowchart illustrating a second processing operation example;

FIG. 4 is a flowchart illustrating a third processing operation example;

FIG. 5 is a flowchart illustrating a fourth processing operation example;

FIG. 6 is a graph showing characteristics of a battery voltage at the end of charging as a reference for determining whether the battery is normal.

FIG. 7 is a graph showing characteristics of a change in battery voltage with respect to the number of times of charging as a reference for determining a memory effect or deterioration.

FIG. 8 is a diagram showing a table for searching for a predetermined value serving as a reference for determining the presence or absence of a memory effect;

FIG. 9 is a flowchart showing a charging processing operation in a fifth processing operation example.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Battery charger 12 ... Battery 14 ... Charger 20 ... Battery temperature detecting means (temperature detecting means) 22 ... Battery voltage detecting means (voltage detecting means) 24 ... Charge amount integrated value detecting means 26 ... Charge number detecting means 30 ... ECU 34: Memory effect recovery charge control unit (first charge control unit) 36: Under charge control unit (second charge control unit) 38: Selection unit 42: Memory effect detection unit 44: Battery deterioration detection unit 50: Table γ, ε, ζ: predetermined values (first to third predetermined values) Tb: battery temperature SOC: state of charge (charge amount) Vb: battery voltage dVb / dt, dVb '/ dt: battery voltage change (battery voltage change) Time change rate)

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Noboru Sato 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (Reference) 2G016 CA03 CB07 CB31 CB33 CC03 CC13 CC28 5G003 AA01 BA01 CA17 CB01 EA05 EA08 GC05

Claims (5)

[Claims] A first charge control means for charging the battery until the charge amount of the battery reaches the first charge amount; and a first charge control means for charging the battery, wherein the charge amount of the battery is smaller than the first charge amount. A second charge control means (36) for charging the battery until the charge amount reaches 2. The charge processing by the first charge control means or the second charge control means
Selecting means (3) for selecting the charging process by the charging control means of
8) and memory effect detecting means (42) for detecting that a memory effect has occurred in the battery, wherein the selecting means has a memory effect occurring in the battery in the memory effect detecting means. If the battery effect is detected, the charging process by the first charging control unit is selected, and if the memory effect detecting unit does not detect that the battery effect is occurring,
A battery charging device, wherein a charging process by the second charging control means is selected. 2. The battery charging device according to claim 1, further comprising: voltage detecting means for detecting a battery voltage.
The memory effect detecting means (42) includes: when the time change rate of the battery voltage at the time when the charging process for the battery is completed is larger than a first predetermined value (γ), the memory effect detecting means (42) A battery charger for detecting occurrence of a battery. 3. The battery charger according to claim 2, further comprising a battery deterioration detecting means, wherein the battery deterioration detecting means has a time change rate of the battery voltage at the time of charging the predetermined number of times before. If the value is larger than the first predetermined value (γ), it is detected that the battery has deteriorated, and the memory effect detecting means (42) determines the time of the battery voltage at the time of charging the predetermined number of times. The battery charger according to claim 1, wherein when the rate of change is equal to or less than the first predetermined value, it is detected that a memory effect has occurred in the battery. 4. The battery charging device according to claim 2, further comprising: a battery deterioration detecting means (44); a temperature detecting means (20) for detecting a battery temperature; and a time change of the battery voltage during past charging. A table (50) for recording the rate as a second predetermined value (ε) corresponding to the battery temperature at the start of charging, wherein the battery deterioration detecting means detects the current charge detected by the temperature detecting means. A second predetermined value corresponding to the battery temperature at the start of charging at the time of charging is obtained from the table, and the difference between this second predetermined value and the time change rate of the battery voltage at the time of the current charging is a third predetermined value ( ζ) If it is larger, it is detected that the battery has deteriorated, and the memory effect detecting means (42) determines whether the battery has deteriorated at the time of the second predetermined value and the current charge. If the difference between the time rate of change of pressure is less than or equal to a predetermined value of the third battery charging apparatus characterized by detecting that the memory effect has occurred in the battery. 5. The battery charging device according to claim 3, wherein the selecting means (38) detects that the battery has deteriorated by the battery deterioration detecting means (44). The second charge control means (36)
A battery charging device for selecting a process by a battery charger.