High-energy-density secondary lithium-ion battery

A high-energy-density secondary lithium-ion battery, comprising:

• a lithium-ion cell, a steel shell, a protection IC, an integrated IC, resistors, capacitors, an inductor, a MicroUSB interface, a plastic structural part, a square rigid FR-4 substrate, a circular rigid FR-4 substrate and a metal cap, for integrating three functions of a constant voltage output, charge management and protection, overcharge and overdischarge protection, overcurrent protection and in a form of three-dimensional space layout and assembly, greatly reducing the space occupied by structural parts that do not contribute to the capacity, to achieve a high energy density, wherein the MicroUSB interface is welded to a side A of the square rigid FR-4 substrate;
• the protection IC, the integrated IC, the resistors, the capacitors, the inductor and the metal cap are welded to the circular rigid FR-4 substrate;
• a side B of the square rigid FR-4 substrate is perpendicularly assembled with the circular rigid FR-4 substrate, an opening of the MicroUSB interface being oriented the same as a side A of the circular rigid FR-4 substrate, and pads on the side B of the square rigid FR-4 are soldered and fixed to pads on a side B of the circular rigid FR-4 substrate;
• the lithium-ion cell is placed inside the steel shell;
• the metal cap is clamped in the plastic structural part and partially exposed from an end face of a first tensile body of the plastic structural part;
• the square rigid FR-4 substrate and the circular rigid FR-4 substrate assembled together are clamped on the plastic structural part in a mating manner with the opening of the MicroUSB interface facing upward;
• the plastic structural part is sleeved at an open end of the steel shell in a mating manner;
• and a positive terminal and a negative terminal of the lithium-ion cell are connected to a first pad and a second pad on the side B of the circular rigid FR-4 substrate through a positive electrode lead wire and a negative electrode lead wire respectively;
• the metal cap satisfies:
• SJ1+Yjmax ≤H2, SJ1+SJ2−0.8 mm≤H2≤SJ1+SJ2−0.2 mm, YH+0.2 mm≤H3≤YH+2 mm, and YH+SJ1+SJ2≤H3+H2≤YH+SJ1+SJ2+2 mm, wherein SJ1 is the height of the first tensile body of the plastic structural part, YJmax is the height of a highest component on the side A of the circular rigid FR-4 substrate, that is, the side directly facing a first cylindrical body of the metal cap, SJ2 is the height of a second tensile body of the plastic structural part, H2 is the height of a second cylindrical body of the metal cap, H3 is the height of a third cylindrical body of the metal cap, and YH is the thickness of the circular rigid FR-4 substrate, all in mm;
• the plastic structural part satisfies:
• M2<SHD<M1, and YJmax<SJ2<YJmax+1 mm, wherein M1 is the diameter of the first cylindrical body of the metal cap, M2 is the diameter of the second cylindrical body of the metal cap, SHD is the diameter of a central hole of the plastic structural part, SJ2 is the height of the second tensile body of the plastic structural part, and YJmax is the height of the highest component on the side A of the circular rigid FR-4 substrate, that is, the side directly facing the first cylindrical body of the metal cap, all in mm;
• the square rigid FR-4 substrate satisfies:
• SJ1≤FH1, UH−UD−FCG≤FH1+FH2≤UH−UD−FCG+1 mm, and YPmax≤FH2, wherein SJ1 is the height of the first tensile body of the plastic structural part, FH1 is the height of a first square flat plate tensile body of the square rigid FR-4 substrate, FH2 is the height of a second square flat plate tensile body of the square rigid FR-4 substrate, UH is the length of the MicroUSB interface, UD is the distance from the plane of an outermost end of an opening portion of the MicroUSB interface to the plane of a nearest edge of the first square flat plate tensile body of the square rigid FR-4 substrate, FCG is the height of a square slot of the square rigid FR-4 substrate, and YPmax is the height of the highest component on the side B of the circular rigid FR-4 substrate, all in mm;
• the circular rigid FR-4 substrate satisfies:
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• wherein YQS is the depth of a notch of a square flat plate tensile body of the circular rigid FR-4 substrate, UF is the thickness of the MicroUSB interface, SD2 is the outer diameter of the second tensile body of the plastic structural part, SDB is the wall thickness of the second tensile body of the plastic structural part, UA is the width of the MicroUSB interface, YB is the radius of the circular rigid FR-4 substrate, RA is the closest distance from the circle center of the circular rigid FR-4 substrate to the square flat plate tensile body notch of the circular rigid FR-4 substrate, FHD is the thickness of the square rigid FR-4 substrate, and M1 is the diameter of the first cylindrical body of the metal cap, all in mm;
• and
• the maximum height DXGmax of the lithium-ion cell satisfies:
• DXGmax≤H−H1−SJ1−SJ2−YH−FH2−GKDH, wherein H is the total height of the secondary lithium-ion battery, H1 is the height of the first cylindrical body of the metal cap, SJ1 is the height of the first tensile body of the plastic structural part, SJ2 is the height of the second tensile body of the plastic structural part, YH is the thickness of the circular rigid FR-4 substrate, FH2 is the height of the second square flat plate tensile body of the square rigid FR-4 substrate, and GKDH is the thickness of the bottom of the steel shell including a convex plate at the bottom, all in mm.