Abstract: The present disclosure provides an electrode assembly and a secondary battery. The electrode assembly includes a first electrode plate, a second electrode plate and a separator. The first electrode plate, the second electrode plate and the separator are wound to a flat structure, and the flat structure comprises a main region and corner regions, the corner regions are provided at two ends of the main region along a width direction of the main region. The first electrode plate and the second electrode plate each are wound to turns. A gap is provided between two adjacent turns of the first electrode plate, the gap includes a first gap and a second gap. The first gap corresponds to the corner region in position, the second gap corresponds to the main region in position, and a dimension of the first gap is larger than a dimension of the second gap.

Abstract: A positive electrode material having particles with P63mc crystal phase structure; and a particle size distribution frequency graph of the positive electrode material comprisecomprises a first peak and a second peak. The positive electrode material has a stable crystal structure, and the electrochemical apparatus using the positive electrode material can maintain high capacity and good cycling performance at a high voltage.

Abstract: A SiOC composite material is in the form of particles, where the particle includes a nucleus formed from a SiOC material, and the nucleus has a carbon fin present on the surface; and a short axis of a largest cross section of the nucleus of any one of the particles is a, a long axis is b, 0.8<a/b?1, and the particles have a porous structure. The SiOC composite material provided in the present invention has good stability, is not prone to swelling during the battery cycling, and has good conductivity, facilitating functions such as capacity performance and electron transport of the SiOC composite material as a silicon negative electrode material, and exhibiting excellent performances such as high capacity, long cycle life, and low swelling rate. This effectively solves the problems such as volume swelling and poor cycling performance in the battery charge-discharge cycles.

Abstract: An electrolyte including a dinitrile compound, a trinitrile compound, and propyl propionate. Based on the total weight of the electrolyte, the weight percentage of the dinitrile compound is X, the weight percentage of the trinitrile compound is Y, and the weight percentage of the propyl propionate is Z, wherein, about 2.2 wt %?(X+Y)?about 8 wt %, about 0.1?(X/Y)?about 2.3, about 5 wt %?Z?about 50 wt %, 1 wt %<Y<5 wt %, and about 0.02?(Y/Z)?about 0.3; wherein the dinitrile compound is one or more compounds selected from butanedinitrile, adiponitrile, 1,4-dicyano-2-butene, and ethylene glycol bis(2-cyanoethyl) ether; and the trinitrile compound is one or more compounds selected from 1,3,6-hexanetricarbonitrile, 1,2,6-hexanetricarbonitrile and 1,2,3-tris(2-cyanoethoxy)propane.

Abstract: An electrochemical apparatus, including a positive electrode, where the positive electrode comprises a positive electrode active material layer; and when the electrochemical apparatus is fully discharged, the positive electrode active material layer comprises a lithium cobalt oxide with a P63mc structure and a lithium-containing metal oxide; and a ratio of a molar concentration of element Li to a molar concentration of other metal elements in the lithium-containing metal oxide is a, where 0<a<0.5.

Abstract: A jelly-roll type electrode assembly includes an electrode plate and a separation layer disposed on at least one surface of the electrode plate. A bonding force of the separation layer to a surface of the electrode plate in a first region of the jelly-roll type electrode assembly is greater than a bonding force of the separation layer to the surface of the electrode plate in a second region of the jelly-roll type electrode assembly. In this way, the bonding force of the separation layer to the surface of the electrode plate in the first region in the jelly-roll type electrode assembly is relatively high. When the electrode plate in the second region is stressed, a slight slip can occur between layers to release the stress, alleviating deformation of the electrochemical device caused by stress concentration.

Abstract: One aspect of the present application provides an electrode assembly, including a first electrode plate, a second electrode plate, and a separator disposed therebetween. The first electrode plate and the second electrode plate are wound or stacked to form the electrode assembly. Wherein the electrode assembly further includes a first electrode tab disposed on the first electrode plate, and an insulating layer including a first portion disposed on the first electrode plate. And, no second electrode plate is disposed between the first portion and the first electrode tab. The present application also provides a battery. The present application intends to at least improve the safety performance of the battery.

Abstract: An electrode assembly, including a positive electrode plate, a negative electrode plate, a separator, a positive electrode tab. The positive electrode plate includes a positive electrode current collector and a positive electrode active substance layer, the negative electrode plate includes a negative electrode current collector and a negative electrode active substance layer disposed on surface of the negative electrode current collector. The positive electrode active substance layer is provided with a first groove. The negative electrode active substance layer is provided with a second groove, the second groove is corresponding to the first groove, the second groove extends along a thickness direction of the electrode assembly to the negative electrode current collector. The second groove is provided with a first protective adhesive inside, so as to ensure thickness consistency between the groove and a body zone of the electrode plate and reducing the risk of short circuit.

Abstract: A positive electrode, including a positive electrode current collector, a positive electrode active material layer, and a coating, where the positive electrode active material layer and the coating are provided on a surface of the positive electrode current collector, and adhesion between the coating and the positive electrode current collector is greater than or equal to 5 N/m. The coating is provided, the coating and the positive electrode current collector are designed, and the adhesion of the coating to the positive electrode current collector is improved so that the safety performance of electrode assemblies containing such positive electrode can be effectively improved.

Abstract: A polymer binder having softening point of 60° C. to 100° C. including a copolymer formed by polymerizing a first monomer, a second monomer, and a third monomer. The first monomer includes at least one of compounds shown in formula (I) or formula (II). The second monomer includes at least one of compounds shown in formula (III) or formula (IV). The third monomer includes at least one of compounds shown in formula (V): R11 is selected from an alkyl group having 0 to 3 carbon atoms; n1 is an integer between 2 and 5; R21 is selected from hydrogen or an alkyl group having 1 to 5 carbon atoms, and M is hydrogen or an alkali metal cation; R22 is selected from hydrogen or an alkyl group having 1 to 5 carbon atoms; and R31 is selected from an alkyl group having 1 to 5 carbon atoms.

Abstract: A negative electrode plate includes: a current collector; and an active material layer, located on the current collector. The active material layer includes a silicon-based material, a carbon material, and a binder. Silicon mass fractions in two places of the active material layer are X1 and X2; the two places cover a same area but are located in different positions, X2?X1, M=X1/X2, and M?0.7. Lithium mass fractions in the two places are Y1 and Y2, respectively; the two places cover the same area but are located in different positions, Y2?Y1, N=Y1/Y2, and N?0.5.

Abstract: A negative electrode material including a silicon compound SiOx, a first conductive layer, and a second conductive layer; where 0.5?x?1.5; at least part of the first conductive layer is present between the silicon compound and the second conductive layer; and the first conductive layer includes graphene, and the second conductive layer includes carbon nanotubes. This application further provides a negative electrode material different from the above negative electrode material in that the first conductive layer includes carbon nanotubes and the second conductive layer includes graphene. An electrochemical apparatus having the negative electrode material combines the advantages of graphene and carbon nanotubes, to obtain long cycle life and low swelling rate.

Abstract: A battery charging method, including: charging a battery in a charging manner under a first ambient temperature T1 until a voltage of the battery reaches first cutoff voltage U1 and/or a current of the battery reaches a first cutoff current I1, so that a first charge capacity of the battery is Q1; and charging the battery in the charging manner under a second ambient temperature T2 until the voltage of the battery reaches a second cutoff voltage U2 and/or the current of the battery reaches a second cutoff current I2, so that a second charge capacity of the battery is, where T2>T1, U2<U1, I1<I2, and Q1=Q2. This application can improve performance of the battery under a high temperature.

Abstract: A negative electrode material includes silicon monoxide particles. A molar ratio A of oxygen to silicon on a surface of the silicon monoxide particle is greater than a molar ratio B of oxygen to silicon inside the silicon monoxide particle, so that the molar ratio A of oxygen to silicon on the surface of the silicon monoxide particle and a molar ratio B of oxygen to silicon at any point above 25 nm from the surface of the silicon monoxide particle satisfy A/B > 1.5, allowing the electrochemical apparatus to have a smaller volume swelling and better cycling performance during charge and discharge cycles.

Abstract: A battery cell including an electrode assembly, a housing, and a first bonding portion. The electrode assembly includes a first end surface, and a first surface and a second surface disposed face away from each other. The housing includes a first inner wall and a second inner wall disposed opposite each other. The first bonding portion includes a first adhesive layer and a second adhesive layer. The first adhesive layer is bonded to the first end surface and extends to the first surface and the second surface to bond with the first surface and the second surface. The second adhesive layer includes a first portion, a second portion, and a third portion connected in sequence, where the second portion is located on a side of the first adhesive layer face away from the first end surface.

Abstract: A silicon-carbon composite particle includes a silicon-based particle and a plurality of graphite particles on surface of the silicon-based particle, where the graphite particles have a particle size of M ?m, the silicon-based particle has a particle size of N ?m, M<N, and 2<N?10. Also, a preparation method of silicon-carbon composite particle. A lithium-ion battery prepared using the active material containing the silicon-carbon composite particles as the negative electrode has good cycling performance and low swelling rate.

Abstract: A negative electrode active material includes a silicon-carbon composite, where the silicon-carbon composite includes a silicon oxide and graphite, a general formula of the silicon oxide is SiOx, 0.5?x?1.6, and the silicon-carbon composite satisfies the following relation: 2?b/a<6, wherein a represents an average particle size of the silicon oxide, and b represents an average particle size of graphite. The negative electrode active material as a negative electrode active material of a lithium-ion battery can prolong cycle life and enhance cycling structure stability.

Abstract: An electrochemical device, including an electrode and an electrolyte. The electrolyte including a dinitrile compound, a trinitrile compound, and propyl propionate. Based on the total weight of the electrolyte, the weight percentage of the dinitrile compound is X, the weight percentage of the trinitrile compound is Y, and the weight percentage of the propyl propionate is Z. Wherein about 2 wt %?(X+Y)? about 11 wt %, about 0.1?(X/Y)? about 8. The electrode including a coating, which including a single-sided sub-coating and a double-sided coating, the electrode with the single-sided sub-coating has an electrode compaction density D1, and the electrode with the double-sided coating has an electrode compaction density D2, where about 0.8?D1/D2? about 1.2. The electrolyte and D1/D2 of the electrodes has a significant effect on the cycle performance of the electrochemical device.

Abstract: An electrolyte including a dinitrile compound, a trinitrile compound, and propyl propionate. Based on the total weight of the electrolyte, the weight percentage of the dinitrile compound is X, the weight percentage of the trinitrile compound is Y, and the weight percentage of the propyl propionate is Z; where about 2 wt %?(X+Y)?about 11 wt %, about 0.1?(X/Y)?about 8, and about 0.01?(Y/Z)?about 0.3. The dinitrile compound comprises a compound of Formula (5): N—R2—(O—R3)n—O—R4—CN (5). The electrolyte is capable of effectively inhibiting the increase in DC internal resistance of an electrochemical device so that the electrochemical device has excellent cycle and storage performance.

Abstract: Embodiments of this application provide a box, a battery, and an apparatus, and relate to the field of battery technologies. The box is provided with a discharge hole, and the discharge hole is configured to discharge, from inside the box, flame produced when thermal runaway occurs in a battery cell. The box is further provided with a fire extinguishing member that is configured to extinguish the flame for cooling when the flame passes through the discharge hole. In this application, the discharge hole and the fire extinguishing member are arranged in the box, so that when the flame produced when thermal runaway occurs in the battery cell passes through the discharge hole, the fire extinguishing member can release a fire extinguishing agent to extinguish the flame for cooling. This prevents the flame from being discharged from inside the box through the discharge hole, thereby improving safety performance of the battery.