Sony Chemicals Corporation

Sony Corporation

Sony Chemical & Information Device Corporation

Norikazu Iwasaki

Kazutaka Furuta

Hisaya Tamura

Masami Kawazu

Motohide Takeichi

Akira Shirakura

Hiroshi Tokunaga

Yuji Yakura

Yukio Yamada

Yuji Furuuchi

Koichi Kawasumi

Hideki Matsuzaka

Toyoji Yamazaki

Yuichirou Ikemoto

Takashi Mori

Hisashi Andoh

A secondary battery with high safety is provided. A heater and a diode are connected in series, and a thermistor is connected in parallel with thus formed series circuit. A fuse is connected in series with thus formed parallel circuit to form a protective circuit, which is attached to an accumulator to complete a secondary battery. In the case of overcharging, the accumulator generates heat so that the thermistor heats up to increase the resistance value. As a result, the current pass through the heater, which generates heat to break the fuse. In the case of short circuit, the diode is reverse-biased and no current passes through the heater so that the fuse does not break.

Secondary batteries having a protective circuit

The invention provides a heat-sensitive material having a heat shrinkable material (e.g., a heat shrinkable resin) having dispersed therein electrically conductive particles, which shrinks on heating to allow an electric current to flow. The invention also provides a heat-sensitive element having a heat-sensitive material and a pair of electrode terminals which are useful as an over-charge protective element of lithium ion secondary batteries.

Heat-sensitive material and heat-sensitive element

A protective circuit for a secondary battery is formed with a heater and a thermistor that are connected in parallel, and a main fuse is connected in series with the parallel circuit. In a secondary battery equipped with this protective circuit, a charging/discharging current passes through the protective circuit and is limited by the operation of the thermistor when the voltage applied during abnormal conditions is relatively low. On the other hand, the current will cause the main fuse to blow when the voltage during abnormal conditions is high.

The protective element A includes a first PTC element , as well as a low-melting-point metal member , a heat-generating member and a second PTC element. A the PTC material &prime; constituting the first PTC element serves as a substrate for the low-melting-point metal member , the heat-generating member or the second PTC element. This protective element using the PTC element can be manufactured easily, with fewer components, and at lower costs. Moreover, the protective element can be made thinner.

Protective element

A PTC element with reduced thickness is manufactured are lower cost by forming an electrode layer on a surface of a flat-plate-shaped PTC material, such that it extends over the upper and lower surfaces and at least one of the side surfaces thereof, and forming an upper surface electrode and a lower surface electrode so that the terminals thereof are positioned on one of the surfaces of the PTC material, by partially removing the electrode layer to segment it into a region where the electrode layer is present on either of the upper or lower surfaces of the PTC material and a region where it extends over the upper and lower surfaces as well as a side surface.

Method for manufacturing a PTC element

A protective element includes at least three electrodes provided on one PTC material. The PTC material operates as at least two PTC elements. This protective element can be manufactured, with fewer components, in an easy manner, and at lower cost, and can cope with overcurrent and overvoltage.

A protective device comprises a fuse element provided to electrodes on a substrate. The fuse element has a liquidus point higher than the mounting temperature of the protective device, and has a solidus point lower than the mounting temperature of the protective device. The difference between the liquidus and solidus points is 5&deg; C. or higher.

Protective device

An electrical current protection device capable of highly safe and rapid shutoff or suppression of electric current is disclosed. In addition to internal electrical current protection capabilities, external environmental triggers are also provided. The current protection device may include substrate-based thermal metallic fuse, PTC current-suppressing protection, thermal heat elements, integrated-circuit based voltage-drop detector, an FET-based current switch, and an external detector for environmental sensing and trigger.

Overcurrent protection device

A PTC-element to be used as a protective device against overcurrent or overvoltage, of which the volume resistivity does not substantially differ before and after a high temperature processing, such as reflowing of solder, and can be preserved even after having been subjected to repeated tripping, which contains a non-conductive crystalline polymer and a particulate conductor material dispersed in the non-conducting crystalline polymer, wherein the particulate conductor material includes electro-conductive particles having irregular surface contours.

PTC-element, protective device and electric circuit board

A battery having a protecting element which has a simple structure and is easy to be miniaturized to permit installation within the battery cell without altering the structure and the production plan of the battery cell to a considerable extent and which has a function of melting down reliably upon detection of an abnormal state of the temperature or current of the battery. The protecting element 1 is formed from a base board 5 which is composed of an insulator layer 2 interposed between a first and a second conductor layer 3 and 4 and is provided with a through-hole 6 so as to bring about electrical conduction between the first and second conductor layers, wherein one of the conductor layers (3) is subdivided into a plurality of independent conductor layer patches (3a and 3b) separated by a vacant space 7 and the so-separated patches (3a and 3b) are bridged with a low-melting metal layer 8 to provide electrical conduction therebetween to build up a fuse unit 11 sealed by a protection member 10 and a safety valve 15 is formed in the through-hole 6 by covering the through-hole 6 with a lamellar closure member 13, wherein the protecting element 1 is installed in the battery cell integrally with the cathode terminal 16 via a PTC element.

Battery and protecting element therefor

To obtain a protective device that can prevent overvoltage and at the same time has an excellent safety and also to make chip type protective devices smaller in size, this invention provides a protective device comprising a substrate, a heating element provided on the substrate, an insulating layer that covers the surface of the heating element, and a low-melting metal piece provided on the insulating layer. Particularly preferably the substrate and the heating element are each formed of an inorganic material. This protective device may be used in combination with a voltage detecting means making use of a zener diode, in such a way that the heating element of the protective device is electrically excited to generate heat when the voltage detecting means detects a voltage exceeding the rated voltage, whereby an overvoltage protector can be set up.

An electrostatic latent image is formed by the Carlson process, etc. on a base (photosensitive body) to develop the electrostatic latent image by a solidification developer in which coloring agent particles are dispersed into a dispersion medium in a solid state at an ordinary temperature and adapted to reversibly repeat fusion by heating at about 30.degree. C. at a temperature above a melting point and solidification by cooling, thus to form a developer picture. Thereafter, the base and a transferred body are caused to be subjected to pressure-contact and heating process to fuse the dispersion medium at a pressure-contact and heating temperature more than the melting point of the dispersion medium to subsequently cool the dispersion medium down to a temperature less than the melting point to peel the transferred body to transfer the developer picture onto the transferred body. Alternatively, the dispersion medium is softened at a pressure-contact and heating temperature set so that this temperature falls within a range where it is not above the melting point to subsequently peel the transferred body to transfer the developer picture onto the transferred body. On the surface of a recording paper, a resin layer compatible with a dispersion medium of a developer may be formed.

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Kanuma, Japan

Norikazu Iwasaki