Low-voltage lithium battery

Abstract

To provide a low-voltage lithium battery which does not use a conductive cable, of which the stability of electric performance is further improved and the internal connection structure of the lithium battery is simplified and which is safer and can be industrialized.SOLUTION: The present application relates to a low-voltage lithium battery. The low-voltage lithium battery includes a circuit module, a middle plastic frame, a wound cell module, a metal case and an insulating sheath, in which the circuit module includes a PCB 11, an outer conductive cap and an inner conductive cap, a front surface of the PCB is provided with a positive copper ring 111 and a negative copper ring 112, the positive copper ring is electrically connected with the outer conductive cap, the negative copper ring is electrically connected with the metal case, a back surface of the PCB is provided with a high-voltage input copper ring, the high-voltage input copper ring is electrically connected with the inner conductive cap, a positive tab of the wound cell module is electrically connected with the inner conductive cap, and a negative tab is electrically connected with the metal case.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] This application relates to the field of lithium battery technology, and in particular to low-pressure 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 uses a voltage-reduction circuit board to convert the high voltage (3.0-4.2V) of a lithium battery to a low voltage of 1.5V. This battery replaces common alkaline and nickel-metal hydride batteries. When manufactured to fit battery sizes such as No. 5 and No. 7, it can be widely used in a variety of devices, including remote controls, electric toys, electric toothbrushes, shavers, wireless microphones, and doorbells. Lithium cells have the advantages of no memory effect, high energy density, and long service life, greatly improving versatility after voltage drop. However, the structure proposed in the application is not rational, its electrical performance is not very stable, and it is merely a conceptual innovation, making it difficult to industrialize.

[0003] A Chinese patent application with publication number CN204966611U and title "1.5V Constant Voltage Lithium-ion Battery" discloses a step-down circuit that can steadily output a low voltage of 1.5V and realize charging and discharging functions through the same port, but does not disclose the specific assembly structure in detail, making it similarly 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 conventional 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 jacket, the circuit module, plastic inner casing, and wound cell module are sequentially installed in the metal case from top to bottom, the insulating outer jacket 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 electrode copper ring and a negative electrode copper ring are provided on the front side of the PCB board, the positive electrode copper ring is electrically connected to the outer conductive cap, and the negative electrode 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, the positive electrode tab of the wound cell module is electrically connected to the inner conductive cap, and the negative electrode tab is electrically connected to the metal case.

[0006] The PCB board in the circuit module of the present application is also equipped with necessary circuits such as a voltage step-down circuit, a constant voltage circuit, a charging circuit, and an over-discharge protection circuit. The outer conductive cap serves as the battery positive electrode and the metal case serves as the battery negative electrode, allowing for stable low voltage output and achieving charging and discharging functions through the same port. Furthermore, the outer conductive cap and inner conductive cap are installed, and a positive electrode copper ring, a negative electrode copper ring, and a high-voltage input copper ring are installed on the PCB board, thereby achieving circuit connections between the wound cell module and the PCB board, and between the low-voltage output element and the PCB board. This eliminates the need for any conductive cables, provides higher electrical stability, simplifies the internal connection structure of the lithium battery, is less susceptible to problems, is safer, and is suitable for industrialization and large-scale production.

[0007] Preferably, the upper part of the metal case is provided with rolling grooves facing inward, which are used to restrict the movement of the wound cell module within the metal case, and also to support the plastic inner frame.

[0008] Preferably, the metal case has a spinning edge facing inward and used to hold down the plastic inner frame, and positive and negative electrode separator sheets are further attached above the spinning edge, and the upper surfaces of parts of the positive and negative electrode separator sheets are further wrapped in an insulating outer jacket.

[0009] Preferably, the inner wall of the plastic middle frame 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 insulator to form a seal and isolate the electrolyte.

[0011] Preferably, the circuit module further includes an elastic ring, the elastic ring including a base ring and a warp piece uniformly disposed around the periphery of the base ring, the back surface of the base ring is welded to the negative electrode 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 insulating sheet, and a lower insulating sheet, the positive electrode tab passes through the central hole of the upper insulating 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. [Effects of the Invention]

[0015] As described above, the present application has at least one of the following beneficial technical effects. 1. The PCB board of the circuit module of this application is also equipped with necessary circuits such as a voltage step-down circuit, a constant voltage circuit, a charging circuit, and an over-discharge protection circuit. The outer conductive cap serves as the battery positive electrode and the metal case serves as the battery negative electrode, enabling stable low voltage output and realizing charging and discharging functions through the same port. 2. This application is equipped with an outer conductive cap and an inner conductive cap, and a positive copper ring, a negative copper ring and a high voltage input copper ring are installed on the PCB board, without using any conductive cables, and 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 suitable for industrialized, large-scale production. [Brief explanation of the drawings]

[0016] [Figure 1] 1 is a perspective view of a low-pressure lithium battery according to an embodiment of the present application. [Figure 2] 1 is a schematic diagram of a half-sectional structure of a low-pressure lithium battery described in an example of the present application. [Figure 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. 2. [Figure 5] FIG. 1 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. 1 is a perspective view of a wound cell module according to an embodiment of the present application. [Figure 8] 1 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 mullion according to an embodiment of the present application. [Figure 10] FIG. 2 is a front perspective view of the circuit module and plastic mullion after assembly according to an embodiment of the present application. [Figure 11] FIG. 1 is a rear perspective view of the circuit module and plastic mullion after assembly according to an embodiment of the present application. [Figure 12]1 is a schematic diagram of a circuit module according to an embodiment of the present application after adhesive has been applied between the circuit module and the plastic mandrel. DETAILED DESCRIPTION OF THE INVENTION

[0017] The present invention will be described in more detail below 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 casing 2, a wound cell module 3, a metal case 4, and an insulating outer jacket 5. The circuit module 1, plastic inner casing 2, and wound cell module 3 are installed in the metal case 4 from top to bottom, and the insulating outer jacket 5 surrounds 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 electrode copper ring 111 and a negative electrode copper ring 112 are provided on the front side of the PCB board 11. The positive electrode copper ring 111 is electrically connected to the outer conductive cap 12, and the negative electrode 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 a commonly used ternary wound cell module or an iron phosphate wound cell module, although other types of wound cell modules may also be used. The voltage range is between 3.0 and 4.2 V. Due to the voltage drop across the PCB board 11, a voltage of 1.5 V is preferably output. Other voltage values, such as 1.2 V or 2.0 V, may be output depending on actual needs. The various functional circuits on the PCB board 11 are already conventional technologies, and the present application does not provide any substantial improvements thereto, so a detailed description is omitted here. The insulating jacket 5 of the present application is preferably made of PVC material, which has heat shrinkability and can tightly wrap the metal case 4 by blowing hot air onto it. The PCB board 11 of the present application is characterized by having 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 being 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 periphery of the base ring 141. The back surface of the base ring 141 is welded to the negative copper ring 112 by surface mounting, and the warped piece 142 is elastically pressed against the spinning edge 42 of the metal case 4. The elastic pressing can prevent the negative copper ring 112 from being pressed tightly against the metal case 4 and the PCB board 11, or from being 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. First, they have high connection strength and reliable fixation; second, they have a large cross-sectional area of the connection, low resistance, and high conductivity. The electronic components on the PCB board 11 are preferably concentrated within the outer conductive cap 12 and the inner conductive cap 13. First, the electronic component arrangement is rational and the internal space of the outer conductive cap 12 and the inner conductive cap 13 is fully utilized; second, the outer conductive cap 12 and the inner conductive cap 13 have high strength and can provide protection, preventing the electronic components from contacting the outside and being damaged; and third, they provide a sealing effect, preventing the intrusion of water and dust, thereby extending the service life of the PCB board 11. The electronic components 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. The electronic components in the outer conductive cap 12 are inductors, capacitors, resistors, etc. Furthermore, the outer conductive cap 12 is exposed and must be in contact with the outside, making it susceptible to impact, and therefore a stronger fixed connection method is required. To this end, a flange edge is provided on the outer conductive cap 12, with a predetermined width that is several times the thickness of the outer conductive cap 12. This allows for a large contact area with the positive copper ring 111, strong fixation, and impact resistance. Because the inner conductive cap 13 is not exposed, is not subject to external impact, and has a somewhat lower strength requirement, a flange edge is not required.

[0022] Referring to FIG. 7 , the wound cell module 3 includes a wound cell 33, an upper insulating sheet 34, and a lower insulating sheet 35. The positive electrode tab 31 passes through the center hole of the upper insulating sheet 34 and has its end welded to the lower surface of the inner conductive cap 13. The negative electrode tab 32 wraps around from the side to the bottom of the winding core 33 and has its 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 via the internal conductive cap 13 and 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 via the metal case 4, elastic ring 14, and negative electrode copper ring 112. After the circuit voltage reduction process on the PCB board 11, the positive electrode copper ring 111 and external conductive cap 12 output the positive electrode of the lithium battery, and the negative electrode copper ring 112, elastic ring 14, and metal case 4 output the negative electrode of the lithium battery.

[0024] 3, a rolling groove 41 is formed inward on the top of the metal case 4, which is used to restrict the movement of the wound cell module 3 within the metal case 4 and also to support the plastic inner frame 2. A spinning edge 42 is formed 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, which can prevent foreign matter such as dust from entering between the elastic ring 14 and the outer conductive cap 12, preventing 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 this application, the wound cells 33 are directly placed in the metal case 4, which requires fewer packaging cases and is less costly than the soft-pack or hard-pack lithium cells of the prior art. The rolling grooves 41 provide a seal for the wound cell module 3, preventing electrolyte leakage, and the upper spinning edge 42 also presses against the plastic inner frame 2 to seal, 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 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, which would cause the PCB board 11 to expire prematurely. By controlling the thickness and cross-sectional shape of the potting adhesive 7, a certain strength can be provided to the potting adhesive 7. In the event of an internal fault within the wound cell module 3, the temperature and air pressure will increase until a certain threshold is reached, at which point the potting adhesive 7 can be broken through to release the pressure, preventing the lithium battery from exploding due to overpressure.

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

[0028] The principle of the present application is as follows: The PCB board 11 in the circuit module 1 of the present application is similarly equipped with necessary circuits such as a voltage step-down circuit, a constant voltage circuit, a charging circuit, and an over-discharge protection circuit, the outer conductive cap 12 serves as the battery positive electrode and the metal case 4 serves as the battery negative electrode, enabling stable low-voltage output and achieving charging and discharging functions through the same port, the outer conductive cap 12 and the inner conductive cap 13 are also installed, and the positive electrode copper ring 111, the negative electrode copper ring 112, and the high-voltage input copper ring 113 are installed on the PCB board 11 to achieve circuit connections between the wound cell module 3 and the PCB board 11, and between the low-voltage output element and the PCB board 11, without using any conductive cables, resulting in higher electrical stability, a simplified internal connection structure for lithium batteries, less problematic, and safer, and the manufacturing method described herein has a reasonable process, a high yield rate, and is suitable for industrialized, large-scale production.

[0029] The above are preferred embodiments of the present application, and are not intended to limit the scope of protection of the present application. 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 electrode copper ring, 112...negative electrode 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 electrode tab, 32...negative electrode 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 electrode isolation sheet, 7...potting adhesive, 100...spinning cutter.

Claims

1. The device comprises a circuit module (1), a plastic inner frame (2), a wound cell module (3), a metal case (4), and an insulating outer jacket (5), and the circuit module (1), the plastic inner frame (2), and the wound cell module (3) are installed in the metal case (4) in this order from top to bottom, and the insulating outer jacket (5) encases the outside of the metal case (4), and the circuit module (1) comprises a PCB board (11), an outer conductive cap (12), and an inner conductive cap (13), and a positive electrode copper ring (111) and a negative electrode copper ring (112) are attached to the front of the PCB board (11). the positive electrode copper ring (111) is electrically connected to an outer conductive cap (12), the negative electrode copper ring (112) is electrically connected to a metal case (4), a high-voltage input copper ring (113) is provided on the back of the PCB board (11), the high-voltage input copper ring (113) is electrically connected to an 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).

2. 2. The low-voltage lithium battery according to claim 1, wherein a rolling groove (41) is provided inward on the top of the metal case (4), which is used to restrict the movement of the wound cell module (3) within the metal case (4) and also to support the plastic inner frame (2).

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

4. 3. The low-voltage lithium battery according to claim 2, wherein the inner wall of the plastic inner frame is provided with a flange edge (21) for supporting 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. 4. The low-voltage lithium battery of claim 3, wherein the circuit module (1) further comprises an elastic ring (14), the elastic ring (14) comprising a base ring (141) and a cambered piece (142) uniformly disposed around the periphery of the base ring (141), the back surface of the base ring (141) being welded to the negative electrode copper ring (112) by surface mounting, and the cambered piece (142) being 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 outer conductive cap (12) and the inner conductive cap (13) are both welded to the PCB board (11) by surface mounting.

8. 8. The low-voltage lithium battery according to claim 7, wherein the electronic components on the PCB board (11) are concentrated within the outer conductive cap (12) and the inner conductive cap (13).

9. 2. The low-voltage lithium battery of claim 1, wherein the wound cell module (3) comprises a wound cell (33), an upper insulating sheet (34) and a lower insulating sheet (35), wherein the positive electrode tab (31) passes through a central hole in the upper insulating 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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