JP3205774B2 - Battery safety monitoring method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for detecting in advance abnormal behavior such as liquid leakage, rupture, explosion, etc., when a battery temperature rises, and for monitoring its safety.

[Prior art]

In recent years, as personal computers, word processors, video cameras, and mobile phones have become smaller, primary and secondary batteries as power sources have become smaller.
High performance, high density, and high reliability are required. By the way, in general, a battery, especially a small and high-quality battery as described above, is subjected to excessive voltage, excessive charging current, and reverse connection voltage due to overdischarge due to a short circuit of an external terminal, trouble at the time of charging, and the like. Temperature may rise, causing liquid leakage, rupture, explosion, and the like.

In order to prevent such an accident, usually,
As safety measures for batteries, PTC elements (elements that increase resistance when the temperature of the battery rises due to current and heating) and safety valve devices (if gas is generated inside the battery and the internal pressure rises abnormally, A device that opens the valve to discharge the gas inside the battery to the outside to prevent the battery from bursting under high pressure) is provided.

However, such a battery safety measure using a PTC element or a safety valve device is expected to have a considerable effect and is practically used, but is standardized before use. Therefore, there is a problem that it is not possible to confirm the safety of the battery in use (during use) and detect and monitor in advance whether there is a danger of liquid leakage, rupture or explosion.

[0005]

SUMMARY OF THE INVENTION The present invention grasps in advance whether or not there is an abnormal state such as battery leakage, rupture, explosion, etc., even during or after use, and accurately and simply determines the safety of the battery. It is an object of the present invention to provide a monitoring method and a device therefor.

[0006]

Means for Solving the Problems In order to solve the above-mentioned problems, the present inventors have made intensive studies on the change values of various characteristics of voltage, current and internal impedance when the temperature of the battery rises. Therefore, surprisingly, prior to the change in voltage or current, the inventors first found that the detected value of the internal impedance changed, and found that the above problem could be solved by using the change in the characteristic value. It was completed. That is, according to the present invention, the internal impedance when the temperature of the battery rises is detected,
There is provided a method for monitoring the safety of a battery when the temperature rises, wherein a failure signal is issued when the detected value indicates a value equal to or greater than a predetermined value. According to the present invention,
Provided is a battery safety monitoring device comprising a device for detecting an internal impedance when the temperature of a battery rises and a device for issuing a breakage signal when the detected value exceeds a predetermined value.

The battery safety monitoring method of the present invention focuses on the fact that, when the temperature rises, the change in the internal impedance value of the battery occurs at a temperature lower than that of the current or voltage, in other words, the change occurs earlier. If such an increase phenomenon of the internal impedance is detected (if the detected value shows a value equal to or more than a predetermined value), an abnormal signal is generated by an alarm device such as a warning sound or a warning light, and the device is used or used. Even after that, it is characterized in that the presence or absence of an abnormal state such as liquid leakage, rupture or explosion of the battery is detected in advance, and the safety of the battery can be monitored accurately and easily.

In the present invention, in order to measure the internal impedance, current and voltage of the battery, a conventionally known measuring device may be used, for example, a measuring device as shown in FIG. 1 may be used. In FIG. 1, E is a battery (sample),
C is a condenser, F is a program thermostat for heating, IA
Is an impedance analyzer, VI is a voltage / current measuring instrument, and PC is a personal computer.

In order to detect the internal impedance according to the present invention, first, the battery E is mounted on a heating chamber F for a heating program.
Next, the temperature of the heating program thermostat is raised, and the internal impedance at each temperature rise may be measured with an impedance analyzer.

There is no special restriction on the heating rate of the heating program constant temperature bath. However, if the heating rate is slow, the measurement takes too much time. Conversely, if the heating rate is fast, the inside of the battery is not sufficiently heated. The temperature is preferably set to 0.5 to 1.0 ° C./min.

The measurement frequency may be arbitrarily set, but a lower frequency is preferable because the change value of the internal impedance is larger and the individual difference of the battery is remarkable. However, if the measurement frequency is too low, the sweeping of the impedance analyzer IA is performed. The time is slow, and it is difficult to accurately follow the impedance change in the process of a rapid change inside the battery.

[0012] The voltage and current of the battery are measured by the voltage / current measuring device VI at each temperature rise. Note that the capacitor C is installed for the purpose of removing the influence of the internal electromotive force of the battery when measuring the internal impedance.

[0013] obtained by the measuring means as described above,
Comparing the change values of the internal impedance, current and voltage at each temperature rise, as apparent from the examples described later, the value of the internal impedance first increases before the battery leaks, breaks or explodes. Then, an increasing phenomenon of the current and voltage values is observed. Also, the change in the numerical value
In the case of internal impedance, it appears relatively early,
Although there is time before battery leakage, breakage, or explosion occurs, changes in voltage and current values appear later than those in the internal impedance, and in some cases, parallel to abnormal battery phenomena. It can be seen that there is no time to avoid these abnormal phenomena.

The present invention focuses on these phenomena, and uses the internal impedance change value as an index, instead of using the change value of the battery current or voltage at temperature rise as an index, and sets the change value to a value equal to or more than a predetermined value. When this is indicated, it is devised to generate a damage signal.Even during or after use, it is necessary to grasp in advance whether there is an abnormal condition such as battery leakage, explosion, explosion, etc.・ Easy monitoring was made possible.

The batteries to be monitored in the present invention include all general batteries, and may be either primary batteries or secondary batteries, or may be fuel cells, regenerative batteries, or solar cells. Examples of the primary battery include a manganese battery, an alkaline manganese battery, a silver battery, and a lithium battery, and examples of the secondary battery include a lead storage battery and a nickel-cadmium battery (alkaline) battery.

[0016]

Now, the present invention will be described in further detail with reference to embodiments. These examples are for facilitating the understanding of the present invention, and do not limit the scope of the present invention in any way.

EXAMPLE 1 A 9V manganese dry battery E was placed in a thermostatic chamber F shown in FIG. 1, and the thermostatic chamber was heated at a temperature rising rate of 1 ° C./min. The value was measured. The result is shown in FIG. From FIG. 1, it can be seen that the change in the value of the internal impedance occurs around 120 ° C., but the change in the current appears only around 130 ° C., and the change in the voltage occurs further around 140 ° C. with a further delay. It has been confirmed that liquid leakage occurs at 140 ° C. FIG. 3 is obtained by differentiating FIG. 2 with respect to time and clarifying each change state. From FIG. 3, it can be seen that the starting temperature of the change is 120 ° C. for the current, 140 ° C. for the voltage, and 115 ° C. for the internal impedance.

Example 2 The values of voltage, current and internal impedance were measured in the same manner as in Example 1 except that the 9 V manganese battery was replaced with a 1.5 V (AA) manganese battery. FIG. 4 shows the results. From FIG. 4, the change in the value of the internal impedance occurs around 130 ° C., but the change in the current is 1
It can be seen that it appears only at around 35 ° C., and that the change in voltage occurs from around 160 ° C. with a further delay. It has been confirmed that liquid leakage occurs at around 160 ° C.

Example 3 The voltage, current and internal impedance values were measured in the same manner as in Example 1 except that the 9 V manganese battery was replaced with a 1.5 V (AA) lithium battery. The result is shown in FIG. From FIG. 5, the change in the value of the internal impedance occurs around 40 ° C., but the change in the current is 13
It can be seen that it appears only at around 0 ° C., and that the change in voltage occurs at around 160 ° C. with a further delay. It has been confirmed that liquid leakage occurs at around 160 ° C.

[0020]

According to the battery safety monitoring method of the present invention, when the temperature rises, the change in the internal impedance value of the battery occurs from a temperature lower than that of the current or the voltage, in other words, the current or the voltage precedes the current or the voltage. Paying attention to the fact that it occurs quickly, if such an increase in internal impedance is detected (if the detected value shows a value equal to or more than a predetermined value), it is damaged by an alarm device such as a warning sound or warning light Since the signal is emitted, the presence or absence of abnormal conditions such as battery leakage, rupture, explosion, etc. is detected in advance even during or after use, and the internal impedance of the battery during unintentional temperature rise etc. When a change is found, the battery can be removed from the equipment in use, so that the safety of the battery can be ensured accurately and easily during or after use of the battery. It has a point.

[Brief description of the drawings]

FIG. 1 shows an apparatus for measuring changes in internal impedance, voltage and current when the temperature of a battery rises.

FIG. 2 is a graph showing changes in internal impedance, voltage, and current when the temperature of the battery rises in Example 1.

FIG. 3 is a graph obtained by differentiating the graph of FIG. 2 with time.

FIG. 4 is a graph showing changes in internal impedance, voltage, and current when the temperature of a battery rises in Example 2.

FIG. 5 is a graph showing changes in internal impedance, voltage and current when the temperature of the battery rises in Example 3.

Claims (2)

(57) [Claims] 1. A method for monitoring safety of a battery, comprising detecting an internal impedance when the temperature of the battery rises , and issuing a breakage signal when the detected value indicates a value equal to or greater than a predetermined value. 2. A battery safety monitoring device comprising : an internal impedance detection device when the battery temperature rises ; and a device that issues a breakage signal when the detected value indicates a value equal to or greater than a predetermined value.