JP2000277061A - Battery - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a battery allowing a battery defect caused by a temperature rise to be easily detected by discoloration without using a measuring device. SOLUTION: This battery having a heat-sensitive pigment is provided with a heat-sensitive paint 15 added with the pigment irreversibly changed in color when the temperature rises to a prescribed high temperature (e.g 230-270 deg.C) on the surface of a positive electrode lead plate 13 fixed to the positive electrode can 11 of a coin type battery 10 with a lead. When the temperature of the coin type battery 10 with the lead rises to the prescribed temperature exceeding heat resistance (e.g. 230-270 deg.C), the pigment is changed in color, and whether the temperature reaches the prescribed high temperature (e.g. 230270 deg.C) or not can be immediately judged visually without using a measuring device, thereby a battery defect can be easily detected.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a battery used as a backup power supply for various electronic devices (electronic devices) and the like, and more particularly, to a component of an electronic device or its component directly mounted on a substrate by soldering. Battery.

[0002]

2. Description of the Related Art With the recent widespread use of various electronic devices, as a backup power supply at the time of a power failure such as an IC memory or a clock circuit incorporated in these devices,
A method of directly mounting a coin type or cylindrical type battery on a printed circuit board or the like has been widely adopted. In order to ensure stable operation over a long period of time, this type of battery for mounting on a substrate mounts one end of a metal lead plate for extracting current directly to the external terminal surface of the battery by spot welding or laser welding. It is often attached by welding, the other end of the metal lead plate is inserted into a terminal hole of a printed circuit board, and attached by soldering or the like in many cases.

[0003]

By the way, in order to mount electronic components on a substrate at low cost, after mounting the electronic components on the substrate, the electronic components are directly mounted on the substrate by solder reflow. In this solder reflow, a cream solder is applied to a substrate, electronic components are placed on the application surface of the cream solder, and the substrate is passed through a reflow oven and heated at a temperature of 220 to 240 ° C. for about 1 minute to remove the solder. It is made to melt. For this reason, electronic components to be solder reflowed are required to have a heat resistance of about 240 ° C. However, when a battery is used as the electronic component, the battery contains a liquid such as an electrolytic solution as one of its components. Most batteries exceeded the boiling point at about 240 ° C., making it difficult to satisfy the requirements for heat resistance.

However, recently, as a battery capable of solder reflow, a small coin-type battery for memory backup of a circuit has been developed as a battery having heat resistance. However, even in the case of batteries having heat resistance, since the batteries are essentially made of an electrolytic solution, their heat resistance is as low as 240 ° C, which is the minimum condition under which solder reflow is possible.
° C. For this reason, for example, the temperature of the reflow furnace set at 240 ° C.
When the temperature rises by 0 ° C. to reach 250 ° C., even if the battery has heat resistance, the performance of the battery sharply decreases, and a situation arises in which the battery cannot be used for the intended use.

[0005] When a situation occurs in which the temperature of the reflow furnace rises above the set temperature, the battery must be removed as a defective product, but an operation for removing the defective product is required. However, there has been a problem that workability is remarkably reduced and time is required. Also,
In order to remove defective products, measurement of battery characteristics such as battery voltage and internal resistance must be performed.However, measurement devices for battery voltage and internal resistance are required, and measurement of battery characteristics is complicated and troublesome. As a result, the cost of the product increases and the number of manufacturing steps increases, which causes a problem that the manufacturing speed of the product decreases and the manufacturing yield decreases.

Accordingly, the present invention has been made to solve the above problems, and has as its object to provide a battery in which a battery failure due to a temperature rise can be easily recognized by discoloration without using a measuring device. Things.

[0007]

Means for Solving the Problems and Their Functions and Effects In order to solve the above problems, the battery of the present invention is provided by increasing the surface temperature of the battery to a predetermined high temperature (for example, 230 to 270 ° C.). The battery is provided with a thermosensitive dye whose color changes irreversibly. As described above, by providing a thermosensitive dye whose color changes irreversibly by increasing to a predetermined high temperature (for example, 230 to 270 ° C.), a predetermined high temperature (for example, 230 to 270) exceeding the heat resistance of the battery is provided. ℃)
The color of the thermosensitive dye changes when the temperature rises, so that a predetermined high temperature (for example, 23
0 to 270 ° C.).

If a measuring device capable of detecting a change in color is used, a predetermined high temperature (for example, 230 to 2
70 ° C.) can be automatically determined in a non-contact manner. In this case, since the inspection can be performed at a higher speed than an electrical inspection requiring contact, the manufacturing speed is improved. The heat-sensitive dye to be used may be appropriately selected in consideration of the set temperature of the reflow furnace or the heat resistance of the battery, and the position to be applied to the battery may be a position that is easily visible.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, an embodiment of the battery of the present invention will be described with reference to FIG. FIG. 1 is a diagram showing a state in which a battery provided with a thermosensitive dye is mounted on a printed circuit board. FIG. 1A is a top view, and FIG. 2B is a front view. 1. Preparation of Battery with Thermosensitive Dye As shown in FIG. 1, a positive electrode can 11 is filled with a pellet of a positive electrode active material mainly composed of manganese dioxide and a separator,
After filling the negative electrode cap 12 with the lithium negative electrode active material, the negative electrode cap 12 was placed in the positive electrode can 11 via an insulating gasket and sealed. Next, the positive electrode lead plate 13 was fixed to the outer surface of the positive electrode can 11 and the negative electrode lead plate 14 was fixed to the outer surface of the negative electrode cap 12 by spot welding or laser welding, respectively, to produce a coin cell battery 10 with leads.

The lead-type coin battery 10 has a capacity of 250
It has a heat resistance of ℃. Although a coin-type battery having a heat resistance of about 230 to 270 ° C. can be manufactured, in this embodiment, a coin-type battery having a heat resistance of 250 ° C. was used. Next, a heat-sensitive paint 15 was applied in a circular shape to the upper part of the positive electrode can 11 of the positive electrode lead plate 13 fixed to the positive electrode can 11 of the coin-type battery 10 with leads, thereby producing a battery provided with a heat-sensitive dye. In addition, if the heat-sensitive paint 15 is applied in a circular shape to a location that is to be the upper position of the positive electrode can 11 in advance, the application step of the heat-sensitive paint 15 can be omitted. The heat-sensitive paint 15 uses a heat-sensitive pigment (thermo paint (product name) manufactured by NOF Engineering Co., Ltd.) having a discoloration temperature of 250 ° C., which changes irreversibly from blue-green to red-gray at 250 ° C. It is produced by adding and mixing.

2. Solder reflow test Next, after applying cream solders 23 and 24 on the printed wirings 21 and 22 formed on the surface of the printed circuit board 20, the positive electrode lead plate 13 of the coin-type battery 10 with leads manufactured as described above and The negative electrode lead plate 14 was placed on the cream solders 23 and 24, respectively. Then
After placing this printed circuit board 20 in a reflow furnace,
After preheating the reflow furnace at a temperature of 150 ° C. for 2 minutes,
Main heating was performed at a temperature of 5 ° C. for 1 minute. When the coin-type battery 10 with leads was observed after the reflow, the color of the heat-sensitive paint 15 was changed to red-gray. This indicates that the coin-type battery 10 with leads was exposed to a temperature of 250 ° C. or higher.

On the other hand, cream solders 23, 2 are placed on printed wirings 21, 22 formed on the surface of printed circuit board 20.
4, the positive electrode lead plate 13 and the negative electrode lead plate 14 of the coin-type battery 10 with leads are placed on cream solders 23 and 24, respectively, and placed in a reflow furnace in the same manner as described above. Furnace at a temperature of 150 ° C for 2
After preheating for one minute, main heating was performed at a temperature of 245 ° C. for one minute.
When the coin-type battery 10 with leads was observed after the reflow was completed, the color of the heat-sensitive paint 15 remained bluish green. This indicates that the coin-type battery 10 with leads is not exposed to a temperature of 250 ° C. or higher.

A battery capable of displaying the temperature rise of the battery by discoloration is disclosed in, for example, JP-A-63-663.
No. 6,865, Japanese Utility Model Application Laid-Open No. 56-104069 or Japanese Utility Model Application Laid-Open No. 61-19962, etc., the battery of the present invention differs from these batteries in the following points. First, in the battery proposed in Japanese Patent Application Laid-Open No. 63-68665, a position where a detector (product name: thermo label) that changes color irreversibly to detect self-heating due to high-rate discharge can be viewed. However, the temperature that can be detected is as low as about 50 ° C. in order to detect self-heating due to high-rate discharge. For this reason, battery failure due to temperature rise cannot be detected by discoloration.

In the battery proposed in Japanese Utility Model Laid-Open Publication No. 56-104069, discoloration due to temperature change is reversible, and the detectable temperature is as low as 46 ° C. at maximum. Battery failure due to the rise cannot be detected by discoloration. Furthermore, the actual opening 61-19962
In the battery proposed in Japanese Patent Laid-Open Publication No. H10-270, the temperature that can be detected is a low temperature of at most about 100 ° C. in order to detect a temperature rise at the time of overcharge, and discoloration due to temperature change is reversible. However, battery failure due to temperature rise cannot be detected by discoloration.

As described above, in the present invention, since the heat-sensitive paint 15 to which the dye which changes color irreversibly is added is applied to the surface of the positive electrode lead plate 13 of the coin-type battery 10 with leads, A predetermined high temperature (for example,
When exposed to a temperature of 230 to 270 ° C., the heat-sensitive paint 15 changes color (for example, changes from blue-green to red-gray), and thus can be visually observed at a predetermined high temperature (for example, 230 to 270) without using a measuring device. ° C).

If a measuring device capable of detecting a change in color is used, a predetermined high temperature (for example, 230 to 2
70 ° C.) can be automatically determined in a non-contact manner. In this case, since the measurement can be performed at a higher speed than an electrical measurement (measurement of voltage or resistance) requiring contact, the manufacturing speed is improved. Further, the dye to be used may be appropriately selected in consideration of the set temperature of the reflow furnace or the heat resistance of the battery, and the position to be applied to the battery may be a position that is easily visible.

[Brief description of the drawings]

FIG. 1 is a diagram showing a state in which a battery provided with a thermosensitive dye is mounted on a printed circuit board, FIG. 1 (a) is a top view,
FIG. 1B is a front view.

[Explanation of symbols]

10: Coin-type battery with lead, 11: Positive electrode can, 12 ...
Negative electrode can, 13: positive electrode lead plate, 14: negative electrode lead plate, 1
5: Thermal paint, 20: Printed circuit board, 21, 22, Printed wiring, 23, 24: Cream solder

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Seiji Morita 2-5-5 Keihanhondori, Moriguchi-shi, Osaka F-term in Sanyo Electric Co., Ltd. 5H011 AA07 AA09 AA12 CC01 DD22 KK04 5H020 AA02 AS14 DD20 EE06 KK17 5H030 AA09 AS11 AS18 FF22 FF66

Claims (3)

[Claims] 1. A battery which can be directly mounted on a substrate of an electronic device by solder reflow, wherein a thermosensitive dye whose color changes irreversibly when the surface temperature of the battery rises to a predetermined high temperature is provided. A battery provided in the battery. 2. The battery according to claim 1, wherein the predetermined high temperature is 230 to 270 ° C. 3. The battery according to claim 1, wherein the battery is a coin-type battery.