▎ 摘　　要

NOVELTY - A secondary lithium battery comprises a dry cell, an electrolyte, and a battery shell. The dry cell is formed by combining several unit sub-cells. The unit sub-cells are formed by stacking or winding a positive electrode sheet, a separator, a negative electrode sheet, and a separator in sequence. The positive electrode sheet comprises a positive electrode material, a conductive agent, a binder, and a current collector aluminum foil or aluminum mesh with reserved tabs. The negative electrode sheet comprises a negative electrode material, a conductive agent, a binder, and a current collector copper foil or copper mesh with reserved tabs. The negative electrode material is mesophase carbon microspheres, artificial graphite, lithium titanate and/or silicon carbon negative electrode. The separator comprises polypropylene or/and polyethylene as a main material. The electrolyte comprises a lithium salt, carbonate and/or carboxylate organic solvent. USE - Secondary lithium battery is used for electrical equipment used in severe cold areas. ADVANTAGE - The ultra-low-temperature and high-capacity secondary lithium battery is economical, and has simple structure. The internal circulation of heat increases the temperature of the battery during operation. The increase in temperature of the battery stimulates the activity of lithium ions in the battery, thereby improving electrical performance, such as operating voltage, current and charge-discharge capacity retention rate in an environment of less than -50 degrees C. DETAILED DESCRIPTION - A secondary lithium battery comprises a dry cell, an electrolyte, and a battery shell. The dry cell is put into the battery shell, injected with the electrolyte, formed into an opening, sealed, and separated. The dry cell is formed by combining several unit sub-cells. The unit sub-cells are formed by stacking or winding a positive electrode sheet, a separator, a negative electrode sheet, and a separator in sequence. The unit sub-cells maximize the heat generated during the operation of the secondary lithium battery and store it in the interior of the secondary lithium battery in a group for heating. The positive electrode sheet comprises a positive electrode material, a conductive agent, a binder, and a current collector aluminum foil or aluminum mesh with reserved tabs. The positive electrode sheet is prepared by performing pulping, coating, baking, rolling and sheeting. The positive electrode material is lithium iron phosphate, lithium iron manganese phosphate, lithium cobalt oxide, lithium manganate, lithium nickel cobalt manganate, lithium nickel cobalt aluminate and/or lithium nickel manganese aluminate. The negative electrode sheet comprises a negative electrode material, a conductive agent, a binder, and a current collector copper foil or copper mesh with reserved tabs. The negative electrode sheet is prepared by performing pulping, coating, baking, rolling and sheeting. The negative electrode material is mesophase carbon microspheres, artificial graphite, lithium titanate and/or silicon carbon negative electrode. The separator comprises polypropylene or/and polyethylene as a main material. The separator is performed by stirring, mixing, cooling, extending, drawing out, drying and slitting. The electrolyte comprises a lithium salt, carbonate and/or carboxylate organic solvent. The lithium salt is lithium hexafluorophosphate, lithium tetrafluoroborate, lithium bis(oxalato)borate, lithium difluoro(oxalato)borate, lithium bis(fluorosulfonyl)imide, lithium trifluoromethanesulfonimide and/or lithium trifluoromethanesulfonate. The carbonate is ethylene carbonate, propylene carbonate, butylene carbonate, fluoroethylene carbonate, vinylene carbonate, dimethyl carbonate, ethyl methyl carbonate and/or diethyl carbonate. The carboxylate is methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propionate, methyl butyrate, ethyl butyrate, propyl butyrate, gamma -butyrolactone and/or delta -valerolactone. The shape of the battery shell is square or cylindrical. The material of the battery shell is steel, aluminum or aluminum plastic. An INDEPENDENT CLAIM is included for preparation of the secondary lithium battery.