JPS63280402A - Ptc element and high output cell pack - Google Patents

Abstract

PURPOSE:To protect an inner cell and a PTC element when an external impact is applied by providing at least two electrodes, and an elastic material disposed between the electrodes, made of a substance having PTC characteristic electrically connected to the electrodes and provided on the outer surface of at least one electrode. CONSTITUTION:The high output cell 10 of a high output cell pack 9 and a PTC element 1 are so provided that an elastic layer 8 is brought into contact with the top inside of a contained jacket 12. The used element 1 is normally formed of two or more electrodes and a substance (PTC composition) 2 having PTC characteristic electrically connected to the electrodes. The composition 2 is prepared by adding monovalent or trivalent metal oxide to BaTiO2 or the mixture of a polymer and conductive particles. The elastic material is preferably rubber having insulation, such as natural rubber or isoprene rubber, and the additive is, for example, frame retarder or flame resistant agent, oxidation preventive agent, stabilizer, or adhesion donating agent such as antimony compound, phosphorus compound.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to battery components and batteries equipped with the components, and more particularly, the present invention relates to a battery component and a battery equipped with the component. (PTC characteristics (positiv
e temperature cocfricien
The present invention relates to a resistive element, that is, a PTC element, and a high-output battery pack equipped with the element.

[Conventional technology]

In a circuit that includes a battery, if a short circuit occurs in the wiring of the circuit or a short circuit occurs due to the destruction of a circuit component, an excessive current flows from the battery incorporated in the circuit, leading to rapid battery consumption and fatal damage to the circuit. If the battery is a high-output battery, there is a risk that a large current will flow through it, causing the battery itself to heat up and explode. Therefore, batteries such as high-output batteries are provided with a PTC element or the like as a protection element. This PTC
When the circuit is short-circuited, the element's resistance value increases due to self-heating due to Joule heat, thereby limiting the overcurrent to a predetermined current or less, and when the short-circuit is removed, the circuit is restored.

Various materials have been developed as materials having this PTC characteristic, such as ceramic materials made by adding monovalent or trivalent metal oxides to BaTiO2, and conductive materials dispersed in polymers such as polyethylene. There are also polymer-based products.

Conventionally, the PTC element 1 mainly consists of PTC elements, as shown in FIG.
C composition 2 and metal electrode plates 3a and 3 sandwiching it
b, and leads (terminals) 4a and 4 connected to the electrode plate.
It consists of b. The manufacturing method of this PTC element is, for example, P
A TC composition is first prepared, and a molded article 2 of this PTC composition is prepared.
Metal foil electrodes are bonded under heat and pressure to the top and bottom of the film to form a laminate, and this laminate is cut to a predetermined size to form the electrode surface 3.
This includes welding the lead 4 by spot welding, soldering, etc.

Conventionally, high-output battery backs incorporated in electronic devices, automatic cameras, etc., have a PTC cable 1 installed between two lithium batteries 10 electrically connected in series, as shown in the circuit diagram of FIG. 3A. As shown in FIG. 3B, the PTC element glue 4 is connected to the electrode 11 of each lithium battery by spot welding or laser welding. The high-output battery pack is constructed by directly housing the battery 10 and PTC element 1 shown in FIG. 3B in a plastic jacket 12 and assembling them as shown in FIG. 4. The jacket 12 is shaped to tightly accommodate the battery and the PTC element, and as shown in FIG. After storage, the jacket 12 of the assembled body divided into two parts is integrated and joined with adhesive as shown in FIG.

[Problem that the invention seeks to solve]

However, even though the battery and PTC element are in close contact with the jacket, during transportation of the high-power battery pack,
Or, during use of the built-in electronic device or electronic camera, vibration, impact, and ambient heat may cause the close contact to widen, and breakage or cracks may occur at the welded portion between the battery and the lead. Such a phenomenon significantly reduces the reliability of electronic devices and the like.

[Means for solving problems]

As a result of various studies to solve the above problems, the present inventors have found that providing an elastic body on the PTC element electrode surface on the inner surface of the jacket of a high-output battery pack is effective in achieving the object of the present invention. This discovery led to the completion of this invention.

That is, the PTC cord according to the present invention has at least 2
The device is composed of two electrodes and a substance having PTC characteristics disposed between the electrodes and electrically connected to the electrodes, and characterized in that an elastic body is provided on the outer surface of at least one of the electrodes. It is something to do.

Further, a high output battery pack which is another aspect of this invention,
High output battery and PT electrically connected in series with the battery
A battery bag consisting of a C$i child and a jacket for storing a battery and a PTC element, the PTC element having at least two electrodes and a PTC characteristic disposed between the electrodes and electrically connected to the electrodes. It is characterized in that an elastic layer is provided on the outer surface of at least one electrode.

This invention will be explained in more detail below.

High-output battery The high-output battery pack of this invention includes a high-output battery and a PTC
It mainly consists of a string and a jacket.

The battery in this invention is a DC voltage source that converts chemical energy into electrical energy, and is a secondary battery or a secondary battery. Examples of such batteries include manganese dry batteries, mercury batteries, alkaline manganese batteries, silver batteries, silver chloride batteries, air temperature batteries, lithium batteries, lead acid batteries, and alkaline batteries. A battery in a preferred embodiment of the present invention has a high output because it includes an element that protects the circuit. For example, there are high-power batteries such as lithium batteries built into automatic cameras. P
In a battery equipped with a TC element as a protection element, this element is provided in series with one or both of the battery terminals as shown in FIG. 3B.

Substance Having PTC Characteristics The PTC element used in the present invention usually consists of two or more electrodes and a substance having PTC characteristics (PTC composition) electrically connected to the electrodes. Examples of this PTC composition include a mixture of saTiOa with a monovalent or trivalent metal oxide added, and a mixture of a polymer and conductive particles.

Polymers that can be used in this invention include polyethylene, polyethylene oxide, t-4-polybutadiene, 1. Polyethylene acrylate, ethylene-ethyl acrylate copolymer, ethylene-acrylic acid copolymer, polyester, polyamide, polyether, polycaprolactam, fluorinated ethylene-propylene copolymer, chlorinated polyethylene, chlorosulfonated ethylene, ethylene-acetic acid Vinyl copolymer, polypropylene, polystyrene, styrene-acrylonitrile copolymer, polyvinyl chloride, polycarbonate, polyacetal, polyalkylene oxide, polyphenylene oxide, polysulfone, fluororesin, and a blend of at least two selected from these. There are polymers, etc. In this invention, the type of polymer, composition ratio, etc. can be appropriately selected depending on desired performance, use, etc.

Furthermore, as the conductive particles dispersed in the polymer, particles of conductive substances such as carbon black, graphite, carbon powder, tin, silver, gold, and copper, and ceramic particles plated with silver or copper may be used. can. In preparing the PTC composition, in addition to the above-mentioned polymer and conductive particles, various additives can be mixed as necessary. Such additives include, for example, flame retardants such as antimony compounds, phosphorus compounds, chlorinated compounds, and brominated compounds, antioxidants, stabilizers, thermally conductive particles, and the like.

In the present invention, the PTC composition is prepared by blending and kneading raw materials, polymers, conductive particles, and other additives in predetermined proportions.

PTC element The PTC element of the present invention comprises the above-described PTC composition and two or more electrodes in contact with it. The types of electrode materials that can be used here are metals that can be used as ordinary electrodes, such as nickel, cobalt, aluminum, chromium, tin, copper, silver, iron (stainless steel), etc. (including iron alloys such as steel),
These include zinc, gold, lead, and platinum. It is desirable that the shape, dimensions, etc. of the electrodes be appropriately selected depending on the use of the PTC element. In this invention, the electrode material may be annealed metal in addition to rolled metal foil.

Next, an example of a method for joining a PTC composition and an electrode in the present invention will be explained. The obtained PTC composition,
For example, a laminate is formed by molding into a film and heat-pressing metal electrodes on the top and bottom of the film, and a laminate is formed by bonding an electrode plate and a PTC composition using a conductive adhesive. A PTC element can be manufactured by cutting this laminate into a predetermined size and connecting lead wires to the electrode surfaces by spot welding, soldering, or the like.

A feature of this invention is that an elastic body is provided on the outer surface of at least one electrode of the PTC element. The shape and dimensions of the elastic body provided on the electrode surface are such that it comes into contact with the inner surface of the jacket, and due to the contact with the jacket, the PT
It is as if the C element is fixed. In Figure 2, PT
An example of an embodiment is shown in which elastic layers 8a and 8b are provided on both sides of the C element electrode.

The elastic body according to the present invention is preferably a rubber having insulating properties, such as natural rubber, isoprene rubber, butadiene rubber, chloroprene rubber, acrylonitrilo-butadiene rubber, butyl rubber, halogenated butyl rubber, ethylene-propylene rubber, etc. Rubber, ethylene propylene-diene rubber, acrylic rubber, ethylene-acrylic rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, urethane rubber, silicone rubber, fluorine rubber, and one or more blended rubbers. . The elastomer may contain additives such as flame retardants such as antimony compounds, phosphorus compounds, chlorine compounds, and bromine compounds, antioxidants, stabilizers, and tackifiers.

Jacket The jacket in this high-output battery pack can be manufactured by molding plastics such as polyvinyl chloride, polyolefin, and polycarbonate, which are commonly used as materials for electrical appliances. It is desirable that the shape, dimensions, material, etc. of the jacket be appropriately changed and selected depending on the battery, PTC element, battery use, etc. Examples of jacket shapes include those shown in FIGS. 4 and 5, for example.

High-output battery pack One of the features of the high-output battery pack in this invention is that an elastic layer is provided in the gap between the inner surface of the jacket and the electrode surface of the PTC element. This elastic layer is made of PTC
Preventing the element and battery from fluctuating and moving inside the jacket, i.e. fixing the battery and PTC element; 1.
It functions to absorb external shocks.

It is preferable that the position, size, shape, etc. of the electrode surface of the PTC element provided with the elastic layer are appropriately selected so as to achieve the above-mentioned functions.

FIG. 1 shows an example of an embodiment in which a high-output battery pack 9 is provided with an elastic layer 8. In this example, an elastic layer 8 is provided inside the top of the jacket 12 that houses the high-power battery 10 and the PTC element 1.
It is set so that it hits.

This invention is not limited to these examples, and various modifications are possible.

[For production]

In this invention having the above-mentioned technical configuration, the PTC element is fixedly supported by the repulsive force of the elastic body pressed by the jacket, and the PTC element built into the jacket does not move even if there is an external impact. . Therefore, the electrical and mechanical connection between the battery and the PTC element is not compromised. When there is an external impact, the elastic body absorbs the impact and protects the internal battery and PTC element as well as their connections. Furthermore, in embodiments in which the elastic body has insulating properties, the risk of short circuit inside the jacket is reduced.

[Example〕 This invention will be specifically explained by showing an example.

Example Silicone rubber (Silicon Rubber RTV!2SH780, manufactured by Toshi) was laminated to a thickness of 1/3 on one side of the electrode of a PTC element having the shape shown in Figure 2, cross-linked and cured, and then stacked in series as shown in Figure 3. It was connected to two lithium batteries. Fourth
Jacket shaped as shown in the figure (30x15x50m
A lithium battery was inserted into (m) with the elastic layer facing upward, the elastic body was pressed and sealed inside the lid of the jacket, and bonded with an adhesive.

The obtained high-output battery pack was dropped from a height of 1.5 m 15 times in the longitudinal direction of the battery, and then a vibration and shock resistance test was conducted by shaking the battery with a vibration of 2011z from the longitudinal direction of the battery at an amplitude of 2+aa+ for 1 hour. . As a result, all of the 50 batteries were found to be free.

Comparative Example A high-output battery pack was prepared in the same manner as in the example except that a conventional PTC element without an elastic body was used, and a vibration and shock resistance test was conducted. As a result, in 3 out of 50 batteries, the welding between the battery electrode and the PTC element lead was broken, and in 3 batteries, the welding between the PTC element electrode and the lead was defective.

〔Effect of the invention〕

The high output battery pack of the present invention provides the following effects.

The elastic body of the PTC element electrode fixes and supports the PTC element, and even if there is an external impact, the PTC inside the jacket will
Do not allow the element or battery to fluctuate.

Therefore, between the battery electrode and the PTC cord lead, and P
The electrical and mechanical connections between the TC element electrodes and their lead terminals are not compromised. Therefore, the reliability of the high-output battery pack can be further improved.

If there is an impact from the outside, the elastic layer can absorb the impact and protect the internal battery and PTC element as well as their connections. Furthermore, in an embodiment in which the elastic layer has insulating properties, the risk of short circuit inside the jacket can be reduced. Since the jacket itself does not need to be in close contact with the battery or the like, the manufacturing cost of molding the jacket can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a high-output battery pack according to the present invention, FIG. 2 is a perspective view of a PTC element according to the present invention, and FIGS. FIG. 4 is a perspective view showing the assembly of a high-output battery pack, FIG. 5 is an exploded perspective view of an example jacket, and FIG. 6 is a perspective view of a conventional PTC element. It is a diagram. 1... PTC element, 2... PTC composition, 3...
Electrode, 4... Lead, 8... Elastic layer, 9... Battery pack, 10... Battery, 11... Battery electrode, 1
2... Jacket, 13... Jacket body, 14
···lid. Application agent Sato -O Figure 1-b Figure 2 Figure 3A Figure 3B Figure 4

Claims (1)

[Claims] 1. A PTC element consisting of at least two electrodes and a substance having PTC characteristics disposed between the electrodes and electrically connected to the electrodes, wherein the outer surface of at least one electrode is A PTC element characterized by being provided with an elastic body. 2. The PTC element according to claim 1, wherein the PTC element as a whole has a substantially plate shape, and an elastic layer is provided on the outer surface of the electrode plate. 3. The PTC element according to claim 1 or 2, wherein the elastic body is a rubber having insulation properties. 4. A battery pack consisting of a high-output battery, a PTC element electrically connected in series with the battery, and a jacket for housing the battery and PTC element, wherein the PTC element is connected to at least two electrodes and between the electrodes. P
A high-output battery pack characterized in that an elastic body is provided on the outer surface of the electrode of the TC element. 5. Claim 4, wherein the battery is a high-output primary battery
Battery pack described in section. 6. The battery pack according to claim 5, wherein the high-output primary battery is a lithium battery.