JP2000050521A - Method for charging battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a power loss at the time of charging a battery and to prevent deterioration of the battery by a memory effect recovery charging process for the battery generating a memory effect, and further executing the memory effect recovering charging process if the recovery of the memory effect is insufficient. SOLUTION: A memory effect detecting means 42 for detecting whether a memory effect is in a battery 12 or not and a memory effect recovery detecting means 43 for detecting whether the memory effect is recovered or not are provided in an ECU 30 of a battery charger 10. Further, a memory effect recovery charge controller 34 for conducting a memory effect recovery charging process for the battery 12, an undercharging controller 36 for operating according to an undercharging mode and a selecting means 38 for selecting a charging mode are provided. In the memory effect recovery charging mode, charging is executed until a charging amount becomes the amount = 10 to 103%, that is, a full charging state or an overcharging state is obtained. Thus, the memory effect generated in the battery 12 can be recovered.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery charging method 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 Recently, batteries have been used as power sources and the like mounted on electric vehicles and the like. As this battery, use of a Ni-MH battery (a nickel-metal hydride secondary battery) that is a nickel-based battery that is small and lightweight and has a high output is considered.

[0003] When charging such a battery, in order to increase the amount of discharge current (unit: Ah), until the battery is fully charged, in other words, SOC ( (State Of Charge: charging state) until SOC = about 100% to 103%.

However, in this charging process, charging is performed until the capacity of the battery (rated capacity) is exceeded, so that at the end of charging, the ratio of the charging current that is not accumulated in the battery but becomes heat becomes large. For this reason, there is a concern that the charging power may be wasted and the battery may be easily deteriorated.

In order to avoid these problems, the amount of discharge current is slightly reduced, but charging is not performed until the battery is fully charged. In other words, the SOC of the battery becomes approximately The introduction of a so-called under-charging method for charging the battery to 90% to 95% is being studied.

[0006]

SUMMARY OF THE INVENTION Incidentally, Ni-MH
As is well known, it has been confirmed that a memory effect occurs in a battery such as a battery using nickel for an electrode under predetermined conditions. 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 battery capacity (discharge current amount) decreases. Therefore, in order to secure a sufficient discharge current amount, it is necessary to restore the memory effect generated in the battery. As a technique for restoring the memory effect, for example, as disclosed in Japanese Patent Application Laid-Open No. 4-351434, a technique is known in which a battery is once discharged before charging and then charged.

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

Therefore, the case where the battery is charged by the above-described under-charging method at all times corresponds to the second occurrence condition, that is, the case where the battery is discharged when the battery is not sufficiently charged. There is a problem that the effect cannot be eliminated and the amount of discharge current of the battery decreases.

On the other hand, when charging is performed until the battery is fully charged, it is known that the memory effect generated in the battery is restored. The process of recovering the memory effect by charging the battery until the battery is fully charged is hereinafter referred to as a memory effect recovery charging process.

Incidentally, the memory effect of the battery may not be sufficiently recovered by performing the memory effect recovery charging process only once. If the memory effect is not sufficiently recovered and the battery with the remaining memory effect is charged, it is not possible to accurately determine the end of charging, and it is possible to secure a predetermined battery capacity. It may not be possible. Even when charging and discharging are repeatedly performed in a state where the predetermined battery capacity cannot be secured, the second effect of the memory effect is also satisfied, and there is a concern that the discharge current amount of the battery based on the memory effect may decrease. .

Therefore, when the memory effect occurs in the battery, a method of repeating the memory effect recovery charging process a predetermined number of times may be considered on the assumption that the memory effect remains in the battery. However, in such a case, even when the memory effect of the battery is sufficiently recovered and the memory effect recovery charging process does not need to be performed, the memory effect recovery charging process may be performed. In this case, there is a concern that the charging power at the end of charging is wastefully consumed and that the battery is likely to be deteriorated.

The present invention has been made in consideration of such problems, and reduces power loss during battery charging, prevents battery deterioration, and ensures that the memory effect generated in the battery is ensured. It is an object of the present invention to provide a battery charging method that makes it possible to prevent a decrease in the discharge current amount of the battery.

[0013]

SUMMARY OF THE INVENTION According to the present invention, after a memory effect recovery charging process (steps S21 to S25) is performed on a battery in which a memory effect has occurred, the memory effect of the battery has been sufficiently recovered. It is determined whether or not the recovery of the memory effect is insufficient (steps S26 to S28). If the recovery of the memory effect is insufficient, the memory effect recovery charging process is further performed (the invention according to claim 1). With this configuration, the memory effect generated in the battery can be reliably restored, and a sufficient charge current (discharge current) of the battery can be secured.

In order to determine whether or not the memory effect of the battery has been sufficiently recovered, a second predetermined value (d is compared with the time change rate of the battery voltage at the end of charging.
V2) is set to a value smaller than a first predetermined value (dV1) which is compared with the rate of change of the battery voltage with time when it is determined whether or not the battery has a memory effect. Is reliably detected, and the memory effect recovery charging process can be performed only when necessary.

[0015]

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 is connected with a battery temperature detecting means 20 for detecting the temperature of the battery 12 (battery temperature Tb) and a battery voltage detecting means 22 for detecting the voltage of the battery 12 (battery voltage Vb). ing.

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 a battery temperature Tb from the battery temperature detecting means 20 and a 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 memory effect detecting means 42 for detecting whether or not the memory effect has occurred in the battery 12, and a memory effect recovery operation for the battery 12 which has been subjected to a memory effect recovery charging process described later. And a memory effect recovery detecting means 43 for detecting whether or not the operation is performed.

The ECU 30 includes a memory effect recovery charge control unit 34 for charging the battery 12 in a memory effect recovery charge mode, which is a charge mode for performing a memory effect recovery charge process. And a selection means 38 for selecting a charging mode by switching output paths of the memory effect recovery charging control section 34 and the under charging control section 36. Have been. In this case, the selection unit 38 switches the output path based on signals from the memory effect detection unit 42 and the memory effect recovery detection unit 43.

In the under charge mode, the battery 1
2, the SOC (St) representing the charge amount of the battery 12
ate Of Charge: state of charge is, for example, SOC = about 9
Charging is performed from 0% to 95%. For this reason, when charging is performed in this under-charge mode, the amount of discharge current is small, but the charging time is short and the charging efficiency is high.
However, since charging is completed before the battery 12 is fully charged, the battery 12 may have a memory effect.

In the memory effect recovery charge mode, the charge amount SOC of the battery 12 is, for example, SOC =
Charging is performed until the battery reaches about 100% to 103%, in other words, a fully charged state or an overcharged state. As described above, by charging the battery 12 to the fully charged state or the overcharged state, the memory effect generated in the battery 12 can be recovered. Hereinafter, the charging process in the memory effect recovery charging mode may be referred to as a memory effect recovery charging process.

Next, the control process of the battery charging device 10 shown in FIG. 1 mainly by the ECU 30 relating to the charging control will be described with reference to the flowchart shown in FIG.

First, the characteristics of the battery voltage Vb at the end of charging will be described with reference to FIGS. 3 and 4 which will be referred to in the following description of the control processing.

FIG. 3 shows a characteristic (Vb-t characteristic) of the battery voltage Vb with respect to the charging time t at the end of charging. FIG. 4 shows the battery voltage V at the end of charging.
5 shows a characteristic (Vb-SOC characteristic) with respect to the SOC of b. 3 and 4, a characteristic example C1 indicated by a solid line.
(Without memory effect) indicates the characteristics of the battery voltage Vb when the memory effect does not occur in the battery 12, and a characteristic example C2 (with memory effect) indicated by a dashed line indicates that the memory effect occurs in the battery 12. In the characteristic example C3 (memory effect not recovered) indicated by a two-dot chain line, the memory effect of the battery 12 is insufficiently recovered and the memory effect is not recovered (in a characteristic example C3 indicated by a two-dot chain line). 5 shows the characteristics of the battery voltage Vb when the memory effect remains).

As shown in FIG. 3, in the characteristic examples C1 to C3, the battery voltage Vb starts to rise sharply as it approaches the end of charging (after time t0). The gradient of the increase in the battery voltage Vb increases in the order of the characteristic examples C1, C3, and C2. That is, the battery voltage Vb increases with a larger gradient when the memory effect is generated in the battery 12 than when the memory effect is not generated.

As described above, since the battery voltage Vb starts to rise sharply at the end of charging, the termination of charging can be determined by monitoring the battery voltage Vb. Here, in FIG. 3, reference numeral Ve1 is the battery 1
2 indicates a first predetermined voltage for determining the end of charging when the memory effect does not occur (characteristic example C1). Reference numeral Ve2 (in this case, Ve2> Ve1) indicates that the battery 12 has a memory effect. (Example of characteristic C2)
5 shows a second predetermined voltage Ve2 for determining the end of charging. That is, the first predetermined voltage Ve1 is a reference value for determining the end of charging in the undercharge mode, and the second predetermined voltage Ve2 is a reference value for determining the end of charging in the memory effect recovery charging mode. is there.

As shown in FIG. 4, in the characteristic example C1, charging is performed until the battery voltage Vb reaches the first predetermined voltage Ve1 (t1 in FIG. 3).
SOC = about 90% to 95% of the SOC is obtained.
That is, in FIG. 4, in the characteristic example C1, the battery voltage V
The charge amount SOCα at time t1 when b reaches the first predetermined voltage Ve1 is 90% ≦ SOC ≦ 95%.

On the other hand, as shown in FIG. 4, in the characteristic example C2, by charging until the battery voltage Vb reaches the second predetermined voltage Ve2 (t2 in FIG. 3), SOC = about 100 % To 103% of the SOC. That is, in the characteristic example C2 in FIG. 4, the time t2 when the battery voltage Vb reaches the second predetermined voltage Ve2.
Of charge SOCβ at 100% ≦ SOCβ ≦ 103%
It is. Such a state of charge SOC (SOC = about 100%
To 103%), the battery 1
2 can be restored.

In FIG. 3, reference numeral C1 'denotes the characteristic example C.
1, the battery voltage Vb is changed to a third predetermined voltage Ve0.
(In this case, a battery voltage change dVb / dt, which is a time change rate (gradient) of the battery voltage Vb at the time point ta when Ve0 <Ve1 is reached, is indicated by reference numeral C2 '.
Indicates the battery voltage change dVb / dt at the time point tb when the battery voltage Vb reaches the third predetermined voltage Ve0 in the characteristic example C2, and is denoted by reference numeral C3 ′.
Represents the battery voltage change dVb / dt at the time tc when the battery voltage Vb reaches the third predetermined voltage Ve0 in the characteristic example C3. The points in time ta and t when the battery voltage Vb reaches the third predetermined voltage Ve0 indicated by these reference signs C1 ', C2' and C3 '.
Based on the battery voltage change dVb / dt at b and tc, as described later, it is determined whether or not the memory effect is generated in the battery 12 (the presence or absence of the memory effect), and the memory effect of the battery 12 is sufficiently recovered. Is determined (whether or not the memory effect remains).

Here, the determination of the presence or absence of the memory effect is made based on the battery voltage change d indicated by reference numerals C1 ', C2' and C3 '.
Vb / dt and a predetermined battery voltage change (gradient) dVb
/ Dt is compared with a first predetermined value dV1 (see FIG. 3), and the determination as to whether or not the memory effect remains is made based on the battery voltage change dVb / dt and a value smaller than the first predetermined value dV1. This is performed by comparing a predetermined battery voltage change (gradient) dVb / dt with a second predetermined value dV2. In this case, in the characteristic example C1, the battery voltage change dVb / d indicated by reference numeral C1 '
Since t is smaller than the first predetermined value dV1 and the second predetermined value dV2, it is determined that the memory effect does not occur in the battery 12 and the memory effect does not remain. In the characteristic example C2, since the battery voltage change dVb / dt indicated by reference symbol C2 'is larger than the first predetermined value dV1, it is determined that the battery 12 has a memory effect. Further, in the characteristic example C3, reference numeral C3 '
Is a first predetermined value d.
V1, it is determined that the memory effect has not occurred in the battery 12, but the battery voltage change dV
Since b / dt is larger than the second predetermined value dV2, it is determined that the memory effect remains in the battery 12.

As shown in the characteristic example C3 of FIG. 4, when the battery effect is left when the battery voltage Vb reaches the first predetermined voltage Ve1 when the memory effect remains in the battery 12, the predetermined charging SOC (SOC = about 90% to 9)
5%), the obtained SOC decreases. In this case, the memory effect of the battery 12 cannot be restored. Therefore, the battery 12 with the remaining memory effect is charged until the battery voltage Vb reaches the second predetermined voltage Ve2 until time t3 (see FIG. 3), so that SOC = about 100% to 103%. % SOC is obtained, and the memory effect is restored. That is, in FIG. 4, in the characteristic example C3, the charge amount SO at the time point t3 when the battery voltage Vb reaches the second predetermined voltage Ve2.
Cγ is 100% ≦ SOCγ ≦ 103%.

Next, the control processing shown in the flowchart of FIG. 2 will be described.

When charging of the battery 12 is started, first, in steps S1 and S2, a charge mode of the memory effect recovery charge mode or the under charge mode is selected.

When making this selection, first, it is determined whether or not a memory effect has occurred in the battery 12 (step S1). The determination process in step S1 is performed based on a flag (memory effect flag) F obtained in steps S16, S17, and S19 described below. This memory effect flag F corresponds to the case where F = 1 indicates that a memory effect has occurred in the battery 12.
= 0 corresponds to the case where the memory effect does not occur in the battery 12.

If it is determined in step S1 that the memory effect flag F is F = 1 and that the memory effect is generated in the battery 12,
Then, it is determined whether or not the memory effect generated in the battery 12 has been sufficiently recovered by the memory effect recovery charging process performed in steps S21 to S25 described later (step S2). The determination process in step S2 is performed in steps S16, S18, and S2 described later.
This is performed based on the flag (memory effect unrecovered flag) F 'obtained in 6 to S28. This memory effect unrecovered flag F 'corresponds to the case where F' = 1 is the case where the recovery of the memory effect of the battery 12 is insufficient (the case where the memory effect remains in the battery 12), and F '= 0 is set when F' = 0. The battery 1
2 corresponds to the case where the memory effect has been sufficiently recovered.

If it is determined in step S2 that the memory effect unrecovered flag F 'is F' = 1 and the recovery of the memory effect of the battery 12 is insufficient, the memory effect recovery charging mode is selected. Is done. On the other hand, in step S2, the memory effect unrecovered flag F 'is set to F'.
= 0, and it is determined that the memory effect of the battery 12 has been sufficiently recovered, or in step S1, the memory effect flag F = 0, and the memory effect has occurred in the battery 12. If it is determined that there is no such charge, the under charge mode is selected.

When the result of the determination in step S1 or S2 is negative and the undercharge mode is selected, charging of the battery 12 in the undercharge mode is started (step S11).

In the under charge mode, first, the battery voltage Vb (characteristic example C1, C2 or C3 in FIG. 3) is compared with a third predetermined voltage Ve0 (step S1).
2) the battery voltage Vb is equal to the third predetermined voltage Ve
The battery voltage change dVb / dt, which is the time change rate of the battery voltage Vb at the time when the battery voltage Vb reaches zero (FIG. 3)
Where C1 ', C2' or C3 '. ) Is obtained (step S13). On the basis of the battery voltage change dVb / dt at the time when the battery voltage Vb becomes Vb = Ve0 obtained in step S13, it is determined in step S16 to be described later whether or not the battery 12 has a memory effect. Done.

Subsequently, it is determined that the charging has been completed (step S14). In step S14, a comparison is made between the battery voltage Vb (characteristic example C1, C2 or C3 in FIG. 3) and the first predetermined voltage Ve1 (in this case, Ve1> Ve0). Then, when the battery voltage Vb reaches the first predetermined voltage Ve1, it is determined that the charging is completed, and the process of charging is performed (step S15). here,
When it is assumed that the memory effect does not occur in the battery 12 (characteristic example C1 in FIG. 4), the battery voltage Vb becomes the first voltage.
Of the battery 1 at the time t1 when the predetermined voltage Ve1 is reached.
The SOC 2 of SOC 2 is about 90% to 95%. In addition, the first predetermined voltage V related to the determination of the end of charging
e1 is the battery temperature Tb from a lookup table or the like.
May be determined based on

Next, it is determined whether or not a memory effect has occurred in the battery 12 (step S1).
6). In this step S16, the battery voltage change dVb / dt at the time when the battery voltage Vb becomes Vb = Ve0 obtained in the step S13 (C in FIG. 3)
Shown as 1 ', C2' or C3 '. ) Is compared with a first predetermined value dV1. When the battery voltage change dVb / dt is greater than the first predetermined value dV1, it is determined that a memory effect has occurred in the battery 12, and the battery voltage change dVb / dt is equal to the first predetermined value dV1. In the following cases, it is determined that the battery 12 has no memory effect.

That is, as shown in FIG.
Since the battery voltage change dVb / dt (indicated by C1 'in the figure) at the time when the battery voltage Vb becomes Vb = Ve0 is smaller than the first predetermined value dV1, the memory effect occurs in the battery 12. It is determined that they have not.
On the other hand, in the characteristic example C2, the battery voltage Vb is Vb = Ve
Since the battery voltage change dVb / dt (indicated by C2 'in the figure) at the time point when it becomes 0 is larger than the first predetermined value dV1, it is determined that the battery 12 has a memory effect.

In step S16, the battery 1
When it is determined that the memory effect has occurred in No. 2, the memory effect existence flag F is set to F = 1 (step S17), and the memory effect unrecovered flag F 'is set to F' = 1 (step S17). S18). On the other hand, if it is determined in step S16 that the memory effect has not occurred in the battery 12, the memory effect flag F is set to F = 0 (step S19).

Next, step S1 and step S2
Is positive and the memory effect recovery charging mode is selected, the charging of the battery 12 in the memory effect recovery charging mode is started (step S2).
1).

In the memory effect recovery charging mode, first,
Similar to the processing in steps S12 and S13, the battery voltage Vb is compared with a third predetermined voltage Ve0 (step S22), and the battery voltage Vb at the time when the battery voltage Vb reaches the third predetermined voltage Ve0 is determined. Then, a battery voltage change dVb / dt, which is a time change rate of the battery voltage Vb, is obtained (step S23). The battery voltage Vb obtained in step S23 is Vb
= Ve0 when the battery voltage changes dVb / dt
In step S26, which will be described later,
A determination is made whether the second memory effect has been sufficiently restored.

Subsequently, it is determined that the charging is completed (step S24). In step S24, a comparison is made between the battery voltage Vb (characteristic example C1, C2 or C3 in FIG. 3) and the second predetermined voltage Ve2 (in this case, Ve2> Ve1). Then, when the battery voltage Vb reaches the second predetermined voltage Ve2, it is determined that the charging has been completed, and the process of ending the charging is performed (step S25). here,
When it is assumed that the memory effect has occurred in the battery 12 (the memory effect has not been recovered) (characteristic example C2 in FIG. 4), the battery voltage Vb at the time t2 when the battery voltage Vb reaches the first predetermined voltage Ve1 is obtained. The charge amount SOC of the battery 12 is:
SOC = about 100% to 103%. Note that the second predetermined voltage Ve2 related to the determination of the end of charging may be obtained from a look-up table or the like based on the battery temperature Tb.

Next, the battery 12 is restored by the memory effect recovery charging process performed in steps S21 to S25.
It is determined whether the memory effect has been sufficiently recovered (step S26). In this step S26, the battery voltage Vb obtained in step S23 is equal to V
Battery voltage change dVb / d when b = Ve0
t (indicated by C1 ', C2' or C3 'in FIG. 3)
Is compared with a second predetermined value dV2. In this case, the second predetermined value dV2 is set to a value smaller than the first predetermined value dV1 for determining whether or not the memory effect has occurred in the battery 12 in step S16. And the battery voltage change dVb / d
When t is greater than the second predetermined value dV2, it is determined that the memory effect is not sufficiently recovered. When the battery voltage change dVb / dt is equal to or less than the second predetermined value dV2, the memory effect is sufficient. Is determined to have been recovered.

For example, as shown in FIG. 3, in the characteristic example C3, the battery voltage change dVb / dt at the time when the battery voltage Vb becomes Vb = Ve0 (indicated by C3 'in the figure).
Is larger than the second predetermined value dV2, the battery 1
It is determined that the memory effect of No. 2 has not been sufficiently recovered (the memory effect remains). Thus, based on the second predetermined value dV2 smaller than the first predetermined value dV1,
By determining whether the memory effect of the battery 12 has been sufficiently recovered, it is possible to detect whether the memory effect of the battery 12 remains.

In the step S26, the battery 1
If it is determined that the recovery of the memory effect of No. 2 is insufficient, the memory effect unrecovered flag F 'is set to F' = 1 (step S27). On the other hand, if it is determined in step S26 that the memory effect of the battery 12 has been sufficiently recovered, the memory effect unrecovered flag F 'is set to F' = 0.
(Step S28). Thus, the battery 1
In the case where the recovery of the memory effect of Step 2 is insufficient, the memory effect non-recovery flag F 'is set to F' = 1, so that the memory effect recovery charging process in steps S21 to S25 is performed again. Therefore, the memory effect is reliably restored.

As described above, according to the above-described embodiment,
Not only when a memory effect occurs in the battery 12,
Even when the memory effect of the battery 12 is not sufficiently recovered, the battery 12 is configured to perform the memory effect recovery charging process. With this configuration, it is possible to reliably recover the memory effect generated in the battery 12 and to prevent a decrease in the amount of discharge current of the battery 12.

Only when the recovery of the memory effect of the battery 12 is insufficient, the battery 12 is repeatedly subjected to the memory effect recovery charging process. For this reason, for example, every time it is detected that the memory effect has occurred in the battery 12, the power loss during battery charging is reduced as compared with the case where the memory effect recovery charging process is simply repeated a predetermined number of times, The deterioration of the battery 12 can be prevented.

In this case, the second predetermined value dV2 for determining whether the memory effect of the battery 12 has been sufficiently recovered is a second predetermined value dV2 for determining whether the memory effect has occurred in the battery 12. 1 is set to a value smaller than the predetermined value dV1. For this reason, it is possible to reliably detect a state in which the recovery of the memory effect of the battery 12 is insufficient, which cannot be detected with the first predetermined value dV1, and only when it is necessary for the battery 12, A recovery charging process can be performed.

It should be noted that the present invention is not limited to the above-described embodiment, but can adopt various configurations without departing from the gist of the present invention.

[0056]

According to the first aspect of the present invention, not only when the memory effect occurs in the battery, but also when the memory effect of the battery is not sufficiently recovered, the memory effect is not applied to the battery. A recovery charging process can be performed.

According to the second aspect of the present invention, it is possible to reliably detect that the memory effect of the battery is not sufficiently recovered.

Therefore, according to the present invention, the loss of power during charging of the battery is reduced, the deterioration of the battery is prevented, and the memory effect generated in the battery is reliably restored. It is possible to prevent the amount 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 showing a control process in the battery charging device.

FIG. 3 is a graph showing characteristics of a battery voltage with respect to a charging time at the end of charging.

FIG. 4 is a graph showing characteristics of a battery voltage with respect to a charged amount at the end of charging.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 ... Battery charging device 12 ... Battery 14 ... Charger 20 ... Battery temperature detection means 22 ... Battery voltage detection means 30 ... ECU 34 ... Memory effect recovery charge control part 36 ... Under charge control part 38 ... Selection means 42 ... Memory effect detection Means 43: Memory effect recovery detection means SOC: State of charge (charge amount) Tb: Battery temperature Vb: Battery voltage dVb / dt: Battery voltage change dV1: First predetermined value dV2: Second predetermined value

Continued on the front page (72) Inventor Keishi Ishikura 1-4-1 Chuo, Wako-shi, Saitama F-term in Honda R & D Co., Ltd. (Reference) 5G003 AA01 BA01 CA17 FA06 GC05 5H030 AA08 AS08 BB18 FF43 FF52

Claims (2)

[Claims] Determining whether or not a memory effect has occurred in a battery; and performing a memory effect recovery charging process on the battery if it is determined that a memory effect has occurred. It is determined whether or not the memory effect of the battery has been sufficiently recovered by the effect recovery charging process, and if the recovery of the memory effect is determined to be insufficient, the memory effect recovery charging process is further performed on the battery. A method for charging a battery, comprising: 2. The method according to claim 1, wherein the determination as to whether or not the battery has a memory effect is based on whether or not the time change rate of the battery voltage at the end of charging is greater than a first predetermined value. The determination as to whether the memory effect of the battery has been sufficiently recovered is made based on whether the time change rate of the battery voltage at the end of charging is greater than a second predetermined value smaller than the first predetermined value. A method for charging a battery, comprising: