Large-capacity secondary battery

A large-capacity secondary battery, comprising:

• a rechargeable cell,
• a steel shell,
• a protection IC,
• an integrated IC,
• resistors,
• capacitors,
• an inductor,
• a LED lamp,
• a plastic part,
• a circular rigid FR-4 substrate,
• a metal cap,
• an insulation pad, and
• an insulation heat shrink film, for integrating multiple functions of a constant voltage output, charge management and protection, and overcharge, overdischarge and overcurrent protection,
• wherein the protection IC, the integrated IC, the resistors, the capacitors, the inductor and the LED lamp are soldered on a side A of the circular rigid FR-4 substrate in a surface-mounted manner;
• the metal cap is soldered on a side B of the circular rigid FR-4 substrate;
• the insulation pad is sleeved on the metal cap;
• the circular rigid FR-4 substrate is mounted within the plastic part with the side B facing upward, and a first cylindrical body of the metal cap partially going beyond a top end of the plastic part;
• a lower end of the plastic part is sleeved at an open end of the steel shell in a mating manner;
• the rechargeable cell is placed inside the steel shell;
• a positive electrode terminal and a negative electrode terminal of the rechargeable cell are correspondingly connected to a first pad and a second pad of the side A of the circular rigid FR-4 substrate through a positive electrode lead wire and a negative electrode lead wire respectively;
• the insulation heat shrink film heat shrinks the insulation pad, the plastic part and the steel shell successively together;
• the circular rigid FR-4 substrate serves as a surface-mounted soldering substrate for the metal cap and other components, and also as an upper support end face and closure end face of the battery;
• the plastic part has three concentric cylindrical tensile bodies, to serve as a support body for the circular rigid FR-4 substrate, a transmission body for the LED lamp, an
• insulation protective body for surface-mounted soldered components on the side B of the circular rigid FR-4 substrate, and a structural body for connection and fixation to the steel shell;
• the insulation pad serves as an insulating layer and a protective layer for the side B of the circular rigid FR-4 substrate, to avoid possible damage of a solder mask layer and exposure of a copper foil due to scratching of the side B of the circular rigid FR-4 substrate by an
• external object;
• the function multiplex, three-dimensional space layout and assembly form of the three parts including the circular rigid FR-4 substrate, the plastic part and the insulation pad greatly reduce the space occupied by structural parts that do not contribute to the capacity, to achieve a large capacity;
• and
• the plastic part includes a first cylindrical tensile body, a second cylindrical tensile body and a third cylindrical tensile body, the first cylindrical tensile body, the second cylindrical tensile body and the third cylindrical tensile body being coaxial, the first cylindrical tensile body being joined with the second cylindrical tensile body in an up-down direction with outer walls thereof being flush with each other, and the top of the second cylindrical tensile body extending beyond an inner wall of the first cylindrical tensile body to form a support platform, and the third cylindrical tensile body being joined with the second cylindrical tensile body in the up-down direction with inner walls thereof being flush with each other;
• the FR-4 substrate is bonded and fixed to the plastic part by an adhesive applied to the support platform and the inner wall in the height direction of the first cylindrical tensile body of the plastic part;
• the plastic part is bonded and fixed to the steel shell by the adhesive applied to an inner wall surface of the steel shell at a joint part of the third cylindrical tensile body of the plastic part and the steel shell;
• the plastic part satisfies 0.3 mm≤SD2−SD3≤2 mm, and HD/2≤SJ2≤1 mm, wherein HD is a height of the surface-mounted LED lamp, SD2 is an inner diameter of the first cylindrical tensile body of the plastic part, SD3 is an inner diameter of the second cylindrical tensile body of the plastic part, and SJ2 is a height of the second cylindrical tensile body of the plastic part, all in mm.