JPH03180782A - Charging device - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a charging device for charging a secondary battery.

[Prior Art] Conventional chargers are equipped with a means for notifying the user when charging is complete, but this generally monitors the terminal voltage of the rechargeable battery being charged and waits until the terminal voltage reaches a predetermined level. When this value is reached, it is assumed that charging is complete and a predetermined display is displayed.

[Problems to be solved by the invention] However, in the conventional example, it is not possible to know specifically how long it will take to complete charging while the battery is being charged, and it is not possible to know specifically how long the battery can be used while it is still being charged. It was not possible to obtain specific information such as whether the battery was fully charged or not.

An object of the present invention is to provide a charging device that can obtain such information.

[Means for Solving the Problems] A charging device according to the present invention includes a voltage measuring means for measuring the voltage between the terminals of a battery to be charged, a data holding means for storing characteristic data of the battery to be charged, and a charging device. The present invention is characterized by comprising an arithmetic control means for determining the degree of charge of the battery from the terminal voltage during charging of the battery and the data held by the data holding means.

[Operation] By means of the above-mentioned means, it is possible to accurately determine the state of charge of the battery to be charged and to obtain a corresponding quantitative indication.

[Example] Hereinafter, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows a block diagram of an embodiment of the present invention. 1
0 is the battery to be charged, 12 is a voltage measurement circuit that measures the voltage between the terminals of battery 10, and 14 is battery 1
a charging circuit that generates a predetermined charging current for charging 0;
20 is an arithmetic control circuit consisting of a microcomputer that controls the operation of the charging circuit 14 and determines the degree of charge of the battery 10 from the output of the voltage measurement circuit 12; 20 is a display device that displays the arithmetic results and control status of the arithmetic control circuit 18; It is. Further, 22 is a memory that stores characteristic data such as charging and discharging characteristics of the battery 10.

The voltage measuring circuit 12 measures the voltage between the terminals of the battery 10 while the charging circuit 14 is charging the battery 10 and transmits the measured voltage value to the arithmetic control circuit 18 . The arithmetic control circuit 18 applies the measured voltage value to the charging/discharging characteristics of the battery 10, determines the degree of charge, etc., and displays the determination result on the display device 2.
Display by 0.

FIG. 2 shows the discharge characteristics when a predetermined load is connected to the Ni--Cd secondary battery. The vertical axis represents the voltage between the terminals, and the horizontal axis represents the elapsed time, and it can be seen that the voltage between the terminals monotonically decreases as time passes. T2 indicates the usable time of a fully charged battery. FIG. 3 shows charging characteristics when a Ni--Cd secondary battery is charged with a predetermined current. The vertical axis is the voltage between the terminals, and the horizontal axis is the time. When the battery is fully charged, the voltage between the terminals decreases a little, so it can be determined whether the battery is fully charged or not. T is the time required to fully charge a completely discharged battery 10.

Table I is a table obtained by converting the discharge characteristics shown in FIG. 2 and the charging characteristics shown in FIG. 3 into data, and is stored in the memory 22. A in Table 1 is numerical data from 100 to 0 indicating the degree of charge,
B is data indicating the time 0-T until full charge,
C is data indicating the time T, ~O until a complete discharge state is reached. For example, the voltage between the terminals of a half-α battery is vo
According to FIG. 2, the usable time is riro (minutes). This state can be considered as T,/T,x 100 (%) being used, which corresponds to the variable A in the memory 28.
It is remembered as 80 years ago. From now on, TF
To/T! It is predicted that the battery will be fully charged in (minutes).

Table 1 Also, FIG. 4 shows the change over time in the charging characteristics shown in FIG. 3. By looking at the inter-terminal voltage change characteristics shown in FIG. 4 in addition to the charging characteristics shown in FIG. 3, the degree of charging can be determined more accurately.

FIG. 5 shows an operation flowchart of the arithmetic control circuit 18. The arithmetic control circuit 18 first puts the charging circuit 14 into an operating state (Sl), and measures the inter-terminal voltage V of the battery E0 being charged using the voltage measuring circuit 12 (Sl). Applying the measured terminal voltage to the table in memory 22 (Table 1),
The corresponding data of A, B, and C are read out (S3), transferred to the display device 24, and displayed (S4).

If the value of A is less than 100 (S5), the charging circuit 14 continues charging since the battery is not fully charged.

However, when the voltage between the terminals decreases (S6), it is fully charged, so in order to finish charging, the voltage between the terminals vF at the time of full charging is substituted into the variable V that stores the voltage value between the terminals. Returning to S3 (S7), A equal to 100 is read from the memory 28.

If A is equal to 100 in S5 (S5), it is a full charge, so the charging circuit 14 is stopped (S8) and the process ends.

[Effects of the Invention] As can be easily understood from the above explanation, according to the present invention, it becomes possible to quantitatively know the charging/discharging level of the battery, the time required for full charging, the usable time, etc.

[Brief explanation of drawings]

Fig. 1 is a configuration block diagram of an embodiment of the present invention, Fig. 2 is a discharge characteristic diagram, Fig. 3 is a charging characteristic diagram, Fig. 4 is a time change characteristic diagram of terminal voltage during charging, and Fig. 5 is the arithmetic control circuit 18
It is an operation flowchart. 10: Battery 12: Voltage measurement circuit 14: Charging circuit 18: Arithmetic control circuit 20: Display device 24: Memory

Claims (1)

[Claims] Voltage measuring means for measuring the voltage across the terminals of the battery to be charged, data holding means for storing characteristic data of the battery to be charged, and voltage between the terminals during charging of the battery to be charged and data held by the data holding means. A charging device comprising: arithmetic control means for determining the degree of charge of the battery.