Low voltage lithium battery

Abstract

To provide a low-voltage lithium battery which does not use a conductive cable, has higher stability of electrical performance, has a simplified internal connection structure of the lithium battery, is safer, and can be industrialized. [Solution] The present application relates to a low-voltage lithium battery, which includes a circuit module, a plastic inner frame, a wound cell module, a metal case and an insulating outer sheath, the circuit module includes a PCB board 11, an outer conductive cap and an inner conductive cap, a positive copper ring 111 and a negative copper ring 112 are provided on the front side of the PCB board, the positive copper ring is electrically connected to the outer conductive cap and the negative copper ring is electrically connected to the metal case, a high voltage input copper ring is provided on the back side of the PCB board, and the high voltage input copper ring is electrically connected to the inner conductive cap, and the positive tab of the wound cell module is electrically connected to the inner conductive cap, and the negative tab is electrically connected to the metal case.

Description

[Technical field]

[0001] This application relates to the field of lithium battery technology, and in particular to low voltage lithium batteries. [Background technology]

[0002] A Chinese patent application with publication number CN203787480U and title "Variable Voltage Cylindrical Battery Device" discloses a low-voltage lithium battery that converts the high voltage (3.0-4.2V) of a lithium battery to a low voltage of 1.5V by a voltage drop circuit board, thereby replacing common alkaline batteries and nickel-metal hydride batteries. When made according to the size of No. 5 battery, No. 7 battery, etc., it can be widely used in various devices such as remote controls, electric toys, electric toothbrushes, shavers, wireless microphones, doorbells, etc. The lithium cell has the advantages of no memory effect, high energy density, and long service life, and the versatility after voltage drop is greatly improved. However, the structure provided in the application is not rational, the electrical performance is not highly stable, and it is only a conceptual innovation, which is difficult to industrialize.

[0003] In a Chinese patent application with publication number CN204966611U and title "1.5V constant voltage lithium-ion battery", a step-down circuit is disclosed that can steadily output a low voltage of 1.5V and realize charging and discharging functions through the same port. However, the specific assembly structure is not disclosed in detail, which also makes it difficult to industrialize. Summary of the Invention [Problem to be solved by the invention]

[0004] In order to solve the technical problems of the industrialization of the traditional low-voltage lithium battery, the present invention provides a low-voltage lithium battery. [Means for solving the problem]

[0005] The technical solution provided in this application is as follows: A low-voltage lithium battery includes a circuit module, a plastic inner casing, a wound cell module, a metal case and an insulating outer casing, the circuit module, the plastic inner casing and the wound cell module are sequentially installed in the metal case from top to bottom, the insulating outer casing surrounds the outside of the metal case, the circuit module includes a PCB board, an outer conductive cap and an inner conductive cap, a positive copper ring and a negative copper ring are provided on the front side of the PCB board, the positive copper ring is electrically connected to the outer conductive cap, the negative copper ring is electrically connected to the metal case, a high voltage input copper ring is provided on the back side of the PCB board, the high voltage input copper ring is electrically connected to the inner conductive cap, the positive tab of the wound cell module is electrically connected to the inner conductive cap, and the negative tab is electrically connected to the metal case.

[0006] The PCB board in the circuit module of the present application is also provided with necessary circuits such as a step-down circuit, a constant voltage circuit, a charging circuit, an over-discharge protection circuit, etc., the outer conductive cap is the battery positive electrode and the metal case is the battery negative electrode, which can stably output low voltage and realize the charging and discharging functions through the same port, and the outer conductive cap and the inner conductive cap are provided, and a positive electrode copper ring, a negative electrode copper ring and a high voltage input copper ring are provided on the PCB board, thereby achieving the circuit connection between the wound cell module and the PCB board, and the circuit connection between the low voltage output element and the PCB board, without using any conductive cables, the electrical performance is more stable, the internal connection structure of the lithium battery is simplified, it is less likely to cause problems, it is safer, and it can be industrialized and produced on a large scale.

[0007] Preferably, the upper part of the metal case is provided with a rolling groove facing inward, which is used to restrict the wound cell module to move within the metal case, and is further used to support the plastic midframe.

[0008] Preferably, the metal case has a spinning edge facing inward and used to hold down the plastic inner frame, a positive and negative electrode separator sheet is further attached above the spinning edge, and a portion of the upper surface of the positive and negative electrode separator sheet is further wrapped in an insulating outer sheath.

[0009] Preferably, the inner wall of the plastic middle is provided with a flange edge, which is used to support the PCB board.

[0010] Preferably, a potting adhesive is further provided between the inner conductive cap and the plastic infill to form a seal and isolate the electrolyte.

[0011] Preferably, the circuit module further includes an elastic ring, the elastic ring includes a base ring and a warp piece evenly arranged around the periphery of the base ring, the back surface of the base ring is welded to the negative copper ring by surface mounting, and the warp piece is elastically pressed against the spinning edge of the metal case.

[0012] Preferably, both the outer conductive cap and the inner conductive cap are welded to the PCB board by surface mounting.

[0013] Preferably, the electronic elements on the PCB board are concentrated within the outer conductive cap and the inner conductive cap.

[0014] Preferably, the wound cell module includes a wound cell, an upper isolation sheet and a lower isolation sheet, the positive electrode tab passes through a central hole of the upper isolation sheet and has an end welded to the lower surface of the inner conductive cap, and the negative electrode tab runs from the side to the bottom of the wound cell and has an end welded to the bottom wall of the metal case. Effect of the Invention

[0015] As described above, the present application has at least one beneficial technical effect as follows. 1. The PCB board in the circuit module of the present application is similarly equipped with necessary circuits such as a step-down circuit, a constant voltage circuit, a charging circuit, and an over-discharge protection circuit, with the outer conductive cap serving as the battery positive electrode and the metal case serving as the battery negative electrode, capable of stably outputting a low voltage and realizing charging and discharging functions through the same port. 2. The present application sets an outer conductive cap and an inner conductive cap, sets a positive copper ring, a negative copper ring and a high voltage input copper ring on the PCB board, and does not use any conductive cable, so that the electrical performance is more stable. 3. The present invention simplifies the internal connection structure of lithium batteries, making them less susceptible to problems, safer, and more amenable to industrialization and large-scale production. [Brief description of the drawings]

[0016] [Figure 1] FIG. 1 is a perspective view of a low-voltage lithium battery according to an embodiment of the present application. [Diagram 2] FIG. 2 is a schematic half-sectional view of the low-pressure lithium battery described in the embodiment of the present application. [Diagram 3] FIG. 3 is an enlarged view of part A in FIG. 2. [Figure 4] FIG. 3 is an enlarged view of part B in FIG. [Diagram 5] FIG. 2 is a front perspective view of a PCB board according to an embodiment of the present application. [Figure 6] FIG. 2 is a rear perspective view of a PCB board according to an embodiment of the present application. [Figure 7] FIG. 2 is a perspective view of a wound cell module according to an embodiment of the present application. [Figure 8] 2 is a schematic diagram of an assembly operation of a circuit module according to an embodiment of the present application. [Figure 9] 1 is a schematic diagram of an assembly operation of a circuit module and a plastic mold according to an embodiment of the present application. [Figure 10] FIG. 2 is a front perspective view of the circuit module and plastic mold after assembly according to an embodiment of the present application. [Figure 11] FIG. 2 is a rear perspective view of the circuit module and plastic mold after assembly according to an embodiment of the present application. [Figure 12]FIG. 2 is a schematic diagram of a circuit module and a plastic mold after adhesive has been applied between them according to an embodiment of the present application. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] The present invention will now be described in further detail with reference to FIGS.

[0018] 1 to 4, an embodiment of the present application discloses a low-voltage lithium battery, which includes a circuit module 1, a plastic inner case 2, a wound cell module 3, a metal case 4, and an insulating outer sheath 5, and the circuit module 1, the plastic inner case 2, and the wound cell module 3 are installed in the metal case 4 from top to bottom, and the insulating outer sheath 5 surrounds the outside of the metal case 4. The circuit module 1 includes a PCB board 11, an outer conductive cap 12, and an inner conductive cap 13. A positive copper ring 111 and a negative copper ring 112 are provided on the front side of the PCB board 11, the positive copper ring 111 is electrically connected to the outer conductive cap 12, and the negative copper ring 112 is electrically connected to the metal case 4. A high-voltage input copper ring 113 is provided on the back side of the PCB board 11, and the high-voltage input copper ring 113 is electrically connected to the inner conductive cap 13. The positive electrode tab 31 of the wound cell module 3 is electrically connected to the inner conductive cap 13 , and the negative electrode tab 32 is electrically connected to the metal case 4 .

[0019] In this embodiment, the wound cell module 3 can be selected from the ternary wound cell module or the iron phosphate wound cell module commonly seen on the market, and of course other types of wound cell modules can be selected. The voltage range is between 3.0 and 4.2 V, and due to the voltage drop of the PCB board 11, it is preferable to output 1.5 V, and other voltage values ​​such as 1.2 V, 2.0 V, etc. can be output according to actual needs. Various functional circuits in the PCB board 11 are already conventional technologies, and the present application does not make any substantial improvements thereon, so the description is omitted here. The insulating jacket 5 of the present application is preferably made of PVC material, which has the characteristics of heat shrinkage and can tightly wrap the metal case 4 by blowing hot air on it. The PCB board 11 of the present application is characterized in that it has a positive copper ring 111 and a negative copper ring 112 on the front side and a high voltage input copper ring 113 on the back side, with the positive copper ring 111 being the low voltage output positive electrode, the high voltage input copper ring 113 being the high voltage input positive electrode, and the negative copper ring 112 being the common negative electrode, and is electrically connected to external conductive members via these three copper rings to realize the functions of high voltage input and low voltage output, without the need for any conductive cables.

[0020] Referring to FIG. 3, the circuit module 1 further includes an elastic ring 14, which includes a base ring 141 and a warped piece 142 uniformly disposed around the base ring 141. The back surface of the base ring 141 is welded to the negative copper ring 112 by surface mounting. The warped piece 142 is elastically pressed against the spinning edge 42 of the metal case 4. The elastic pressing can avoid the occurrence of a situation where the pressing between the metal case 4 and the negative copper ring 112 on the PCB board 11 is not tight or the negative copper ring 112 is crushed.

[0021] 3, the outer conductive cap 12 and the inner conductive cap 13 are both welded to the PCB board 11 by surface mounting. The first is high connection strength and reliable fixation, the second is large cross-sectional area of ​​the connection part, small resistance and high conductive performance. The electronic components in the PCB board 11 are preferably concentrated in the outer conductive cap 12 and the inner conductive cap 13, the first is reasonable arrangement of the electronic components and full use of the internal space of the outer conductive cap 12 and the inner conductive cap 13, the second is high strength of the outer conductive cap 12 and the inner conductive cap 13, can play a protective role, the electronic components do not contact the outside and are not damaged, and the third is a sealing effect, which prevents the intrusion of water and dust, and extends the service life of the PCB board 11. The electronic elements in the inner conductive cap 13 of the present application are three-in-one step-down chips, which belong to the prior art and have the advantages of high integration and small volume, making the design of the PCB board 11 easier, and the electronic elements in the outer conductive cap 12 are elements such as inductors, capacitors, and resistors. In addition, the outer conductive cap 12 is exposed and needs to be in contact with the outside, and is easily impacted, so a stronger fixed connection method needs to be adopted, so that a flange edge is particularly provided on the outer conductive cap 12, and the flange edge has a certain width, which is several times the thickness of the outer conductive cap 12, so that the contact area with the positive copper ring 111 is large, the fixation is strong, and it can withstand impact. The inner conductive cap 13 is not exposed, is not impacted from the outside, and has a relatively low requirement for strength, so there is no need to provide a flange.

[0022] Referring to FIG. 7 , the wound cell module 3 includes a wound cell 33, an upper isolation sheet 34 and a lower isolation sheet 35, the positive electrode tab 31 passes through the central hole of the upper isolation sheet 34 and has an end welded to the lower surface of the inner conductive cap 13, and the negative electrode tab 32 wraps around from the side to the bottom surface of the winding core 33 and has an end welded to the bottom wall of the metal case 4.

[0023] The specific connection principle of the circuit is as follows: the positive electrode tab 31 of the wound cell module 3 is connected to the PCB board 11 through the internal conductive cap 13 and the high voltage input copper ring 113, and the negative electrode tab 32 of the wound cell module 3 is connected to the PCB board 11 through the metal case 4, the elastic ring 14, and the negative electrode copper ring 112. After the circuit step-down process on the PCB board 11, the positive electrode copper ring 111 and the external conductive cap 12 output the positive electrode of the lithium battery, and the negative electrode copper ring 112, the elastic ring 14, and the metal case 4 output the negative electrode of the lithium battery.

[0024] 3, a rolling groove 41 is provided inward on the upper part of the metal case 4, which is used to restrict the movement of the wound cell module 3 in the metal case 4 and also to support the plastic inner frame 2. A spinning edge 42 is provided inward on the metal case 4 and is used to hold the plastic inner frame 2. A positive and negative electrode isolation sheet 6 is further attached above the spinning edge 42. The positive and negative electrode isolation sheet 6 can block foreign matter such as dust from entering between the elastic ring 14 and the outer conductive cap 12, thereby avoiding a short circuit between the two. A part of the upper surface of the positive and negative electrode isolation sheet 6 is further wrapped in an insulating outer jacket 5, which further fixes the positive and negative electrode isolation sheet 6.

[0025] In the present invention, the wound cell 33 is directly inserted into the metal case 4, which requires less packaging and is less costly than the soft-packed or hard-packed lithium cells of the prior art. The rolling groove 41 is provided to achieve a seal for the wound cell module 3, making it difficult for the electrolyte to leak, and the upper spinning edge 42 further presses and seals the plastic inner frame 2, achieving an integrated seal.

[0026] Referring to FIG. 3, a flange edge 21 is provided on the inner wall of the plastic inner frame 2, which is used to support the PCB board 11. A potting adhesive 7 is further provided between the inner conductive cap 13 and the plastic inner frame 2 to form a seal and isolate the electrolyte, preventing the electrolyte from contacting the PCB board 11 and causing corrosion, causing the PCB board 11 to expire too soon. By controlling the thickness and cross-sectional shape of the potting adhesive 7, the potting adhesive 7 can have a certain strength, so that when an internal fault occurs inside the wound cell module 3, the temperature rises and the air pressure increases, and when it reaches a certain threshold, the potting adhesive 7 can break through and release the pressure, avoiding the explosion caused by the overpressure of the lithium battery.

[0027] An insulating jacket 5 is preferably made of PVC material and encases the metal case 4 by heat shrinkage.

[0028] The implementation principle of the present application is as follows: The PCB board 11 in the circuit module 1 of the present application is similarly provided with necessary circuits such as a step-down circuit, a constant voltage circuit, a charging circuit, an over-discharge protection circuit, etc., the outer conductive cap 12 is the battery positive electrode, and the metal case 4 is the battery negative electrode, so that a low voltage can be stably output, and the charging and discharging functions can be realized by the same port, and the outer conductive cap 12 and the inner conductive cap 13 are provided, and the positive copper ring 111, the negative copper ring 112, and the high voltage input copper ring 113 are provided on the PCB board 11 to realize the circuit connection between the wound cell module 3 and the PCB board 11, and the circuit connection between the low voltage output element and the PCB board 11, without using any conductive cable, the electrical performance is more stable, the internal connection structure of the lithium battery is simplified, it is less likely to cause problems, and it is safer, and the manufacturing method described in the present application has a reasonable process, a high yield rate, and can be industrialized and produced on a large scale.

[0029] The above are preferred embodiments of the present application, and the scope of protection of the present application is not limited based on these embodiments. Therefore, any equivalent changes based on the structure, shape, and principle of the present application should be included within the scope of protection of the present application. [Explanation of symbols]

[0030] 1...circuit module, 11...PCB board, 111...positive copper ring, 112...negative copper ring, 113...high voltage input copper ring, 12...outer conductive cap, 13...inner conductive cap, 14...elastic ring, 141...base ring, 142...warped piece, 2...plastic inner frame, 21...flange edge, 3...wound cell module, 31...positive tab, 32...negative tab, 33...wound cell, 34...upper isolation sheet, 35...lower isolation sheet, 4...metal case, 41...rolling groove, 42...spinning edge, 5...insulating outer sheath, 6...positive and negative isolation sheets, 7...potting adhesive, 100...spinning cutter.

Claims

1. The device includes a circuit module (1), a plastic inner frame (2), a wound cell module (3), a metal case (4) and an insulating outer sheath (5), the circuit module (1), the plastic inner frame (2) and the wound cell module (3) are installed in the metal case (4) from top to bottom, the insulating outer sheath (5) covers the outside of the metal case (4), the circuit module (1) includes a PCB board (11), an outer conductive cap (12) and an inner conductive cap (13), a positive copper ring (111) and a negative copper ring (112) are provided on the front side of the PCB board (11), the positive copper ring (111) is electrically connected to the outer conductive cap (12), and the negative copper ring (112) is electrically connected to the outer conductive cap (12). a high-voltage input copper ring (113) is provided on the rear surface of the PCB board (11), the high-voltage input copper ring (113) is electrically connected to an inner conductive cap (13), a positive electrode tab (31) of the wound cell module (3) is electrically connected to the inner conductive cap (13), and a negative electrode tab (32) is electrically connected to the metal case (4), the outer conductive cap (12) and the inner conductive cap (13) are all welded to the PCB board (11) by surface mounting, and electronic elements on the PCB board (11) are concentratedly arranged within the outer conductive cap (12) and the inner conductive cap (13).

2. 2. The low-voltage lithium battery according to claim 1, characterized in that the upper part of the metal case (4) is provided with a rolling groove (41) facing inward, the rolling groove (41) is used to restrict the wound cell module (3) so that the wound cell module (3) cannot move within the metal case (4), and is further used to support the plastic inner frame (2).

3. The low-voltage lithium battery according to claim 2, characterized in that the metal case (4) has a spinning edge (42) facing inward and used to hold the plastic inner frame (2), a positive and negative electrode separator sheet (6) is further attached above the spinning edge (42), and a part of the upper surface of the positive and negative electrode separator sheet (6) is further wrapped in an insulating outer cover (5).

4. 3. The low-voltage lithium battery according to claim 2, wherein the inner wall of the plastic inner frame (2) is provided with a flange edge (21), which is used to support the PCB board (11).

5. 5. The low-voltage lithium battery of claim 4, further comprising a potting adhesive (7) between the inner conductive cap (13) and the plastic inner frame (2) to form a seal and isolate the electrolyte.

6. The low-voltage lithium battery according to claim 3, characterized in that the circuit module (1) further includes an elastic ring (14), the elastic ring (14) includes a base ring (141) and a warped piece (142) evenly arranged around the periphery of the base ring (141), the back surface of the base ring (141) is welded to the negative electrode copper ring (112) by surface mounting, and the warped piece (142) is elastically pressed against the spinning edge (42) of the metal case (4).

7. 2. The low-voltage lithium battery according to claim 1, wherein the wound cell module (3) comprises a wound cell (33), an upper isolation sheet (34) and a lower isolation sheet (35), the positive electrode tab (31) passes through a central hole of the upper isolation sheet (34) and has an end welded to the underside of the inner conductive cap (13), and the negative electrode tab (32) runs from the side to the bottom of the wound cell (33) and has an end welded to the bottom wall of the metal case (4).

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