69results about How to "Prevent internal short circuit" patented technology

Disclosed is an electrode comprising a first organic/inorganic composite porous coating layer formed on its surface, wherein the first coating layer includes inorganic particles and a binder polymer for interconnecting and fixing the inorganic particles, and has micropores formed by interstitial volumes among the inorganic particles. An electrochemical device including the same electrode is also disclosed. Further, disclosed is a method for manufacturing an electrode having an organic/inorganic composite porous coating layer on the surface thereof, comprising the steps of: (a) coating a current collector with slurry containing an electrode active material and drying it to provide an electrode; and (b) coating the surface of electrode obtained from step (a) with a mixture of inorganic particles with a binder polymer. A lithium secondary battery including the electrode shows improved safety and minimized degradation in battery performance.

An alkaline battery separator comprising an alkali-resistance synthetic fiber, a fibrillated organic solvent-spun cellulose fiber having a Canadian standard freeness value of 10 to 280 ml, and a mercerized pulp having a Canadian standard freeness value of not less than 550 ml is prepared. In the separator, the proportion of the alkali-resistance synthetic fiber, the proportion of the fibrillated organic solvent-spun cellulose fiber, and the proportion of the mercerized pulp relative to the total amount of the separator are respectively 25 to 62% by mass, 5 to 25% by mass, and 33 to 50% by mass, provided that the total amount of the separator is 100% by mass. The alkali-resistance synthetic fiber may comprise a polyvinyl alcohol-series fiber having an average fiber fineness of not more than 1 dtex. The alkaline battery separator may further comprise a polyvinyl alcohol-series binder in a proportion of 3 to 20% by mass relative to the total amount of the separator. The alkaline battery separator of the present invention may have a shrinkage by the area of not more than 3.5% after immersing in an aqueous solution of potassium hydroxide having a concentration of 40% by mass at 80° C. for 24 hours and a stiffness strength of not less than 2 N.

The present invention provides a lithium ion secondary battery including: an electrode group including a belt-like positive electrode and a belt-like negative electrode that are wound with a separator interposed therebetween; and a can with a bottom for accommodating the electrode group, wherein the positive electrode has a positive electrode current collector and a positive electrode mixture layer carried on the positive electrode current collector, the negative electrode has a negative electrode current collector and a negative electrode mixture layer carried on the negative electrode current collector, and a porous heat-resistant layer is partially provided between the separator and at least one of the positive electrode mixture layer and the negative electrode mixture layer. Since a porous heat-resistant layer is thus placed, a high performance lithium ion secondary battery capable of efficiently preventing internal short circuit due to overheating while preventing decrease in battery characteristics can be provided.

The invention discloses a polypropylene microporous membrane with a three-layer compound structure and a preparation method of the polypropylene microporous membrane. The polypropylene microporous membrane with the three-layer compound structure comprises surface layers A and C and a core layer B, wherein the surface layers A and C are made from beta crystal form homo-polypropylene and the core layer B is made from beta crystal form co-polypropylene; or, the surface layers A and C are made from beta crystal form co-polypropylene and the core layer B is made from beta crystal form homo-polypropylene. The preparation method comprises the following steps: (1) respectively melting and mixing the beta crystal form homo-polypropylene and the beta crystal form co-polypropylene, carrying out co-extrusion via a three-layer compound die head and cooling the extruded molten membrane; and (2) stretching the three-layer compound beta crystal form polypropylene membrane. The polypropylene microporous membrane with the three-layer compound structure, disclosed by the invention, has high fusing temperature and low closed pore temperature simultaneously and has the advantages that when the membrane is used for battery diaphragms, closed pores can be timely molten to terminate the battery reaction and the internal short caused by fusing can be avoided, so that the safety is greatly increased.

The present invention discloses a thermal-resistant and flame-retardant membrane and a preparation method thereof, and applications. According to the preparation method, the cost is controllable, theoperation of the preparation process is simple, and thus the preparation method is suitable for mass production. The prepared thermal-resistant and flame-retardant membrane has a double-layer composite structure with both thermal stability and flame retardancy, the membrane can prevent internal short circuit of a battery at a lower temperature, so that severe thermal runaway of the battery is prevented, and thus safety accidents, such as burning and explosion are prevented; the membrane can effectively prevent the battery from burning and exploding after the thermal runaway of the battery occurs under the conditions of overcharge, puncture and abuse; and the membrane has good applications in the chemical power supply system, especially in lithium ion batteries.

A nonaqueous secondary battery comprises a positive electrode, a negative electrode and a separator interposed between the positive electrode and the negative electrode, wherein at least one of the positive electrode and the negative electrode is provided with a current collector composed of a film-like or fibrous resin layer having a conductive layer on both sides, and the separator has a higher thermal deformation temperature than the resin layer.

The invention relates to an anode of a lithium-ion battery and a lithium-ion battery prepared from the same. The anode of the lithium-ion battery comprises an anode base material layer, an anode active substance layer, and an aluminum oxide micro-pore coating which can replace traditional lithium-ion battery PP and PE isolating membranes. The aluminum oxide micro-pore coating on the surface of the anode of the lithium-ion battery not only has relatively high mechanical intensity, but also has good electrolyte-keeping capability, avoids the phenomenon of closing holes at a high temperature, furthermore guarantees a battery to have better high-temperature adaptability in a temperature application scope, and is applicable for a high-power lithium-ion battery.

The invention discloses a technology for improving the wavy shape of the edge of a lithium ion battery positive plate. The technology comprises the following steps: (1) rolling the laminated lithium ion battery positive plate by using a hot-pressing silica gel skin material with the inner diameter of 5 to 10 mm; (2) after rolling, putting the positive plate into an oven without vacuum pumping forbaking for 2 to 4 h, wherein the baking temperature is 100 to 120 DEG C; and (3) after baking, cooling a plate roll to the room temperature, carrying out stripping to prepare the positive plate. The laminated positive plate is rolled by using the silica gel skin material, the rebound and stress of the plate during rolling can be buffered effectively, and the uniform rolling orderliness and tensionof the plate are guaranteed; the pressure of the plate is released by baking the plate at high temperature, uniform stress of the plate during stripping is guaranteed, and the wavy shape of the edgeof the positive plate is avoided. Therefore, internal short circuits of a lithium ion battery in the using process are avoided, and the potential safety hazards, such as fire and explosion, of the lithium ion battery are reduced.

The invention provides a pole piece and a secondary battery with the same. The pole piece comprises a current collector and an active substance layer, the current collector comprises a main body part and a tab, the active substance layer is coated on the surface of the main body part, and the tab extends from one end of the main body part along a first direction; a first insulating part is formed on the end face, provided with the tabs, of the main body part, and a second insulating part different from the first insulating part is formed on the end face, not provided with the tabs, of the main body part. The pole piece has good end face insulation protection, and the safety performance of the secondary battery can be improved.