JPH04370777A - Battery abnormality detection system - Google Patents

Abstract

PURPOSE:To enable the detection of such abnormality of a battery that one cell alone is short-circuited among a plurality of cells connected in series by using a battery voltage and a residual capacity of the battery in calculation. CONSTITUTION:A battery is made up of a plurality of cells connected in series. A current detecting section detects a discharge current of the battery. A residue calculating section subtracts a consumed capacity of the battery from an initial capacity of the battery to calculate the residue of the battery. A voltage detecting section detects the voltage of the battery. An abnormality detecting section judges that abnormality is caused in the battery when a detection voltage falls below a certain threshold under a condition there is a residue in calculation and displays the abnormality of the battery on an abnormality display section.

Description

[Detailed description of the invention]

0001

[Industrial Application Field] The present invention relates to a battery abnormality detection method that displays a battery abnormality when a voltage drop is detected in a state where the battery is calculated to have sufficient charge. It is.

0002

2. Description of the Related Art It is known to detect abnormalities in a battery based on the battery voltage. According to this method, it is possible to detect abnormalities such as a complete short circuit or an open circuit in the battery.

0003

[Problem to be Solved by the Invention] However, in a battery configured by connecting multiple cells in series, if only one cell is short-circuited, the voltage will be within the allowable range of normal voltage. With the method of detecting battery abnormalities, this type of battery abnormality is not detected and the battery is repeatedly charged and discharged. The present invention was created in view of this point, and by using the battery voltage and the calculated remaining capacity of the battery, only one of a plurality of cells connected in series is short-circuited. The aim is to be able to detect battery abnormalities such as these.

0004

[Means for Solving the Problems] FIG. 1 is a diagram illustrating the principle of the present invention. As shown in the figure, the battery abnormality detection method of the present invention includes a battery, a current detection unit that detects the value of current flowing from the battery, a clock, a set value for the initial capacity of the battery, and a current value of the current detection unit. and a remaining capacity calculation unit that calculates the remaining capacity of the battery by substituting the time information from the clock into the remaining capacity calculation formula, a voltage detection unit that detects the voltage value of the battery, and a remaining capacity calculation unit that calculates the remaining capacity of the battery by substituting the time information from the clock into the remaining capacity calculation formula. If the detected voltage value of the voltage detection unit falls below a predetermined voltage value under the condition that the voltage is detected, the abnormality detection unit determines that the battery is abnormal. The present invention is characterized by comprising an abnormality display section that displays the presence of an abnormality.

[0005]

[Operation] A battery is composed of a plurality of cells connected in series. The current detection unit detects the discharge current of the battery. The remaining capacity calculation unit calculates the remaining capacity of the battery by subtracting the used capacity of the battery from the initial capacity of the battery. The used capacity can be determined by time-integrating the discharge current of the battery. The voltage detection section detects the voltage of the battery. The abnormality detection unit determines that an abnormality has occurred in the battery when the detected voltage falls below a certain threshold in a state where it is calculated that there is remaining battery power. Displayed on the error display section.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 2 is a block diagram of one embodiment of the present invention. In the figure, 1 is a battery, 2 is a current detection resistor, 3 is a load, 4 is a discharge current calculation section, 5 is a battery usage capacity calculation section, 6 is a clock, 7 is a battery remaining amount calculation section, 8
9 is the battery voltage detection unit, 10 is a,
11 is a battery abnormality display section, 12 is a charger, and 13 is a charging control section. Note that parts 4, 5, 6, 7, 9, and 10 can be realized by a computer and a program.

The device shown in FIG. 2 exists in, for example, a notebook computer. The battery 1 is composed of a plurality of cells (for example, eight cells), and these cells are connected in series. The current from the battery 1 flows through the resistor 2. The load 3 is made up of various devices that make up the computer. The discharge current calculation unit 4 calculates the discharge current from the voltage across the resistor 2. The discharge current calculation unit 4 calculates the discharge current value to be larger than the current that actually flows. For example, if the actual discharge current is 100mA,
In the calculation, it is assumed that 110 mA flows.

The battery usage capacity calculation section 6 calculates the time integral value of the discharge current based on the discharge current value from the discharge current calculation section 4 and the time information from the clock 6. The time integral value of this discharge current becomes the battery usage capacity. The remaining battery capacity calculation unit 7 determines the remaining capacity (synonymous with remaining capacity) by subtracting the used capacity from the initial capacity. This remaining amount is displayed on the remaining amount display section 8. For example, the initial capacity is 1000
If the capacity used is 300mAh, the remaining capacity is 7
Information indicating that the remaining amount is 0% is displayed on the remaining amount display section 8.

The battery voltage detection section 9 detects the voltage across the battery. The a, b, c value calculation unit 10 detects whether or not the battery is abnormal. a represents the time until the battery voltage drops below a certain threshold, b represents the calculated time until complete discharge, and c represents a-b. c is 0
If it is smaller, it is determined that a battery abnormality exists, and the battery abnormality display section 11 displays that there is a battery abnormality. Types of battery abnormalities include battery life, single cell short, impedance increase,
There are other issues such as insufficient capacity. Charger 12 supplies charging current to battery 1 . The charging control unit 13 is the charger 12
When the battery reaches full charge, charging is stopped and the battery usage capacity calculation unit 7 is notified of this fact. Although not shown, a switch is provided in front of the resistor 2, and this switch is open during charging.

FIG. 3 is a diagram showing battery voltage and remaining capacity. As shown in the diagram on the left, in the case of a normal battery, the time a when the battery voltage reaches the voltage drop detection level coincides with the time when the remaining battery capacity (actual capacity) reaches 0. Since the calculated discharge current is set to be larger than the actual discharge current, the calculated time b for the remaining battery capacity to become 0 is shorter than the time a, and c
≧0. However, c=a−b.

The diagram on the right side of FIG. 3 is a diagram for explaining the case of an abnormal battery (insufficient capacity). For example, if one cell in a battery made up of a plurality of cells is short-circuited, the capacity will be insufficient. In the case of insufficient capacity, the time a until the battery voltage reaches the voltage drop detection level is shorter than the time a in the case of a normal battery, and c<0.

FIG. 4 is a processing flow for displaying remaining power and detecting voltage. The diagram on the left side of FIG. 4 shows the processing flow for displaying the remaining amount. In step R1, discharging from full charge is started. At this time, the initial capacity is set. The initial capacity setting value is set after taking into account temperature, aging, battery variations, etc.
Set it so that the battery becomes “out of charge” before detecting a voltage drop. This is also the reason why the above-mentioned discharge current value is calculated to be larger than the actual discharge current. Of course, just one of them is fine. In step R2, the used capacity of the battery is calculated. In step R3, the calculated used capacity is subtracted from the initial capacity setting value of the battery to determine the remaining capacity, and the determined remaining capacity is displayed. In step R4, it is checked whether the voltage drop detection flag is set. Yes
If so, proceed to step R6; if No, proceed to step R.
Proceed to step 5. In step R5, it is checked whether there is any capacity left. If Yes, the process returns to step R2, and if No, the process proceeds to step R7. In step R6, an abnormality display is performed. Next, the process advances to step D4. In step R7,
Displays “no remaining amount”. After displaying “No remaining power”, a voltage drop is detected and power-off processing begins.

The diagram on the right side of FIG. 4 shows the processing flow of voltage detection. In step D1, voltage detection is performed. Step D
In step 2, it is checked whether the detected voltage is below the voltage drop detection level. If Yes, proceed to step D3; if No, return to step D1. In step D3, a voltage drop detection flag is set. In step D4, power-off processing is performed.

[0014]

Effects of the Invention As is clear from the above description, according to the present invention, battery abnormality can be detected with a simple configuration of calculating the remaining amount of the battery and monitoring the battery voltage. can encourage the exchange of

[Brief explanation of drawings]

FIG. 1 is a diagram explaining the principle of the present invention.

FIG. 2 is a block diagram of one embodiment of the invention.

FIG. 3 is a diagram showing battery voltage and remaining capacity.

FIG. 4 is a diagram showing a processing flow for displaying remaining power and detecting voltage.

[Explanation of symbols]

1 Battery 2 Current detection resistor 3 Load 4 Discharge current calculation section 5 Battery usage capacity calculation section 6 Clock 7 Battery remaining amount calculation section 8 Remaining amount display section 9 Battery voltage detection section 10 a, b, c value calculation unit 11　Battery abnormality display section 12 Charger 13 Charging control section

Claims (1)

[Claims] [Claim 1] A battery, a current detection unit that detects the value of current flowing from the battery, a clock, a set value of the initial capacity of the battery, a current value of the current detection unit, and time information from the clock, in a remaining capacity calculation formula. By substituting into An abnormality detection section that determines that the battery is abnormal when the detected voltage value falls below a predetermined voltage value, and an abnormality display section that displays that there is an abnormality when the abnormality detection section detects a battery abnormality. A battery abnormality detection method characterized by comprising: