JPS59134557A - Collected battery - Google Patents

Abstract

PURPOSE:To enable a battery to be protected from over-charge by making a protecting device to operate certainly even at a rapid charging time, and also to enable discharge to be carried out without any obstacle by providing an automatic recovery type thermal fuse and a protecting device consisting of a parallel circuit set up with a resistor adjacent to the fuse, a diode facing the charging direction and a diode facing the discharging direction. CONSTITUTION:A thermal fuse 2 is connected in series to plural number of enclosed type secondary batteries connected in series in order, a resistor 3 to heat the fuse while charging is disposed adjacent to the thermal fuse 2, and at the same time, a diode 4 facing the charging direction is connected to the resistor 3 in series, a diode 5 facing the discharging direction to exclude the resistor 3 from a discharging circuit at a discharging time of the battery is connected in parallel to the resistor 3 and the diode 4 so as to set up a protecting device 6 with beforementioned components together with the thermal fuse 2. Accordingly, an over-charge can be dissolved by an accelerated operation of the thermal fuse 2 due to heating of the resistor 3 in the protecting device, and a discharge under a high temperature condition can be performed without any obstacle by a detour excluding function of the resistor 3 due to the diode 5 facing the discharge direction and same function of the diode 4 facing the charge direction.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a battery assembly consisting entirely of sealed secondary batteries connected in series. More specifically, the present invention relates to a protection device that protects a battery from overcharging and allows the battery to be discharged appropriately without leaking or swelling due to an increase in internal pressure.

Conventional configurations and their problems As portable electronic devices have become more popular in recent years, assembled batteries, in which multiple secondary batteries are connected in series and housed in a single case, have become widely used as power sources. . As shown in Figure 1, an assembled battery mainly consisting of sealed nickel-cadmium storage batteries (hereinafter referred to as Ni-Cd batteries), which has particularly excellent rapid charging characteristics, is made up of multiple Ni-Cd batteries 1 according to the specified voltage of the device. A self-resetting temperature fuse (
(hereinafter referred to as a temperature fuse) 2.

The temperature fuse in this assembled battery has a current of about 1C (size commensurate with the battery capacity) of about 2, and functions to protect the battery from overcharging when performing rapid charging using a voltage control method.

In other words, if voltage control becomes impossible for some reason during the charging process, a temperature heater close to the battery detects a temperature rise in the overcharge region of the battery, and if the temperature rises to the set (operating) temperature of the temperature heater, For example, it activates the heater to stop charging.

However, this method had the following drawbacks. In other words, Figure 2 shows the charging time and battery voltage when a battery assembly is constructed with six Ni-Cd batteries with a nominal capacity of 500 mAh and is charged at 500 mA of 1C phase in an atmosphere of 20°C. (A), battery internal pressure (B), and battery temperature rise (q).As can be seen from this Figure 2, for example, if the operating temperature of the temperature fuse is 70°C, this operating temperature By the time the temperature of the battery rises, the internal pressure of the battery has reached 24 to 9 cm2 or higher, and there is a risk of electrolyte leakage or swelling due to the increase in internal pressure. ℃, the internal pressure of the battery when the fuse is activated is about 10Kg·m2, and there is almost no possibility of leakage, but in an atmosphere of 40℃, the fuse operation makes it impossible to discharge to the load.

In order to compensate for this drawback of not being able to discharge, the operating temperature of the temperature heater is set at 50 to 60'C, and as a countermeasure against leakage due to increased internal pressure, a liquid absorbing mat is used to prevent the electrolyte from leaking outside the battery case. Although this problem was solved by incorporating it into all cases, the discharge characteristics of the assembled battery were not satisfactory due to the decrease in electrolyte, etc.

OBJECT OF THE INVENTION The present invention solves the drawbacks of the above-mentioned conventional examples.
The purpose of this invention is to enable discharge even under high temperature conditions, with the presence of a protective device not causing any hindrance during discharging, even if errors occur due to some cause during charging of the assembled battery.

Structure of the Invention In order to achieve all of the above objects, the assembled battery of the present invention has a temperature heater connected in series to a plurality of series-connected sealed secondary batteries, and is heated in the vicinity of the temperature heater during charging. At the same time, a diode in the charging forward direction is connected in series with all the resistors, and a diode in the discharging forward direction is connected in parallel with the resistor and the diode to exclude the resistor from the total discharge circuit when the battery is discharged. It is characterized in that it is used as a protection device together with a temperature heater.

In the assembled battery of the present invention, overcharging can be eliminated by accelerating temperature heating caused by heat generated by the resistor in the protection device, and discharging under high temperature conditions can be prevented by the resistor by the forward discharge diode and by the forward charge diode. Thanks to the detour removal function, this can be done without any problems.

Description of examples Hereinafter, details of the present invention will be explained with reference to embodiments shown in the drawings.

FIG. 3 is a schematic diagram showing an assembled battery in an embodiment of the present invention. In the figure, 1 indicates a plurality of N i -Cd%
2 is a temperature fuse close to the battery and connected in series thereto, 3 is a resistor close to the temperature fuse 2, and a diode 4 for forward charging is connected to this. Reference numeral 5 denotes a forward discharge diode, which constitutes a parallel circuit with the resistor 3 and the diode 4 in series. The protection device 6, which is a feature of the present invention, is composed of the temperature fuse 2, the resistor 3, and the diodes 4 and 5.

Now, an assembled battery was constructed with each of the above-mentioned elements as follows.

Ni-Cd battery 1: All 6 batteries with a nominal capacity of 500 mAh Temperature fuse 2: Automatic reset resistor with operating temperature of 70°C 3: 40°C after 60 minutes when 500 mA is applied
Metal film resistance diode that causes a temperature rise of
The current value was set to A, and charging was performed using a constant voltage control method. The temperature fuse was activated 68 minutes after charging started, and charging stopped.

At this time, the internal pressure of the battery was 8.7 x -2, and no leakage of electrolyte or swelling of the battery occurred. Furthermore, discharging after charging was completed without activating the temperature fuse.

As described above, according to this embodiment, even if the temperature fuse is activated during normal charging or voltage control becomes impossible, charging can be stopped without increasing the hk in the battery. Discharge can be performed without any problem.

Effects of the Invention As described above, in the assembled battery of the present invention, even during rapid charging, the protection device can be operated reliably to protect the battery from overheating, and the battery can be discharged without any trouble. Further, the set temperature of the temperature heater and the heat generation characteristics of the resistor can be arbitrarily selected depending on the secondary battery used, allowing a wide range of applications.

[Brief explanation of the drawing]

Figure 1 is a diagram showing a battery assembly made up of conventional secondary batteries.
Figure 2 shows the relationship between charging time, battery voltage, battery internal pressure, and battery temperature rise when sealed nickel-cadmium storage batteries are charged with a current equivalent to all 10 battery packs connected in rows on six sides. The figure is a schematic diagram of an assembled battery in an embodiment of the present invention. 1...Ni-Cd battery, 2...Temperature fuse, 3...Resistor, 4, 5...Diode, 6...Protective device. Name of agent: Patent attorney Toshio Nakao and 1 other person No. 1
figure

Claims (1)

[Claims] It is equipped with a plurality of sealed secondary batteries connected in series and a protection device connected in series to the batteries, and the protection device includes an automatic reset temperature heater, a resistor close to this fuse, and a diode in the forward charging direction. A collective battery consisting of a parallel circuit with a diode in the forward direction of discharge.