A lithium battery structure

Abstract

A lithium battery structure comprises a winding core within a steel shell, a cap assembly sealed to the outer steel shell by a metal ring, and a through-hole provided on the cap assembly. After being sealed to the outer periphery of the steel shell by the metal ring, vacuum is drawn and electrolyte is injected through the through-hole, thereby making full use of the internal space of the steel shell, increasing the capacity of the lithium battery and reducing the battery cost. An explosion-proof valve is also installed in the through-hole, which can be stably fixed in the through-hole to seal the cavity under normal circumstances. However, once an abnormality occurs inside, a large amount of gas will be filled inside the outer shell, causing the air pressure to increase. The explosion-proof valve can open the through-hole to connect the inside and outside of the steel shell, and the excess gas in the shell can be discharged along the through-hole for pressure relief, thereby reducing the air pressure inside the shell, thereby effectively preventing the lithium battery from exploding.

Description

Technical Field

[0001] The present invention relates to a battery structure, in particular to a lithium battery structure. Background Art

[0002] With the development of modernization and the improvement of living standards, many electrical appliances and appliances used by people require batteries as energy sources. The batteries used in daily life are mainly divided into two categories: dry cell batteries and lithium batteries. Among them, dry cell batteries are a type of voltaic battery. They are easy to manufacture and low in cost, but relatively speaking, they have poor performance, low power consumption, and are disposable consumables, which cause significant environmental pollution. Lithium batteries are a type of battery that uses lithium metal or lithium alloy as the negative electrode material and a non-aqueous electrolyte solution. The most widely used are soft-pack lithium batteries, which are batteries with a polymer shell on a liquid lithium-ion battery, such as common mobile phone batteries. Soft-pack lithium batteries have the advantages of good safety, light weight, and large capacity, but they have a limited number of models and are subject to significant restrictions on shape design, making them unsuitable for use in appliances using traditional cylindrical dry cell batteries.

[0003] Dry cell batteries are generally cylindrical and widely used in various electrical devices. They are easy to purchase, carry, and replace, but their performance is poor. To improve this situation, a step-down conversion type lithium-ion battery has been developed to replace dry cell batteries. While retaining the external structure of the cylindrical battery, it uses a lithium-ion cell and has a cap assembly with a voltage conversion function inside the battery. For example, the cylindrical battery in the publication number 201174405Y, entitled "A Dual-Voltage Output Cylindrical Battery," has excellent performance. This battery structure includes: an external steel shell, a soft-pack lithium-ion cell placed inside the steel shell and sealed with an aluminum-plastic film, and a cap assembly with a step-down circuit at the top of the cell that is connected to the positive and negative electrodes of the soft-pack lithium-ion coil. The steel shell houses a soft-pack battery cell sealed with aluminum-plastic film. Due to the soft-pack's sealing structure, the soft-pack has a sealed edge, which takes up space when placed inside the steel shell. Furthermore, due to material limitations, the soft-pack cannot be pressed strongly to prevent cracking and leakage. This creates a gap between the soft-pack cell and the steel shell, limiting space utilization and impacting battery capacity. Furthermore, the thickness of the sealed aluminum-plastic film itself takes up a certain amount of space within the shell, further impacting battery capacity. Summary of the Invention

[0004] The present invention aims to provide a lithium battery structure that can fully utilize the inner shell space to further improve the capacity of the lithium battery.

[0005] The lithium battery structure described in the present invention includes a steel shell, a lithium battery core installed in the steel shell, and a cap assembly covering the port of the steel shell; the cap assembly includes a circuit board with a voltage conversion function, a metal ring sealed and connected to the top of the steel shell is provided at the bottom or periphery of the circuit board, and a positive electrode assembly fixedly installed above the circuit board; the positive electrode of the core is connected to the positive electrode lead-in end of the circuit board circuit, and the negative electrode of the core is electrically connected to the steel shell; the steel shell is in contact with the metal ring and is electrically conductive, the metal ring is connected to the negative electrode lead-in end of the circuit board, and the positive electrode assembly is connected to the positive electrode output end of the circuit board; a through hole is also provided on the cap assembly to communicate with the inner cavity of the steel shell, and an explosion-proof valve is installed in the through hole, which seals the through hole when the pressure inside the steel shell is normal and opens the through hole when the pressure inside the steel shell is high.

[0006] The lithium battery structure of the present invention has a lithium battery core directly placed within a steel shell. The battery cap assembly is sealed to the outer steel shell via a metal ring. A through-hole is provided in the cap assembly. After the battery cap assembly is sealed to the outer steel shell via the metal ring, the lithium battery can be vacuumed and electrolyte injected through the through-hole. No aluminum-plastic film soft pack is required within the steel shell to seal the core and electrolyte. This allows full utilization of the internal space of the steel shell, thereby increasing the capacity of the lithium battery and reducing battery costs. Furthermore, an explosion-proof valve is installed within the through-hole. Under normal use, the explosion-proof valve can be stably fixed within the through-hole to seal the cavity. However, if an abnormality occurs within the lithium battery and the core generates high heat, causing the electrolyte to vaporize, the interior of the outer shell will be filled with a large amount of gas, resulting in an increase in air pressure. The explosion-proof valve can then open the through-hole to connect the inside and outside of the steel shell. Excess gas within the shell can be discharged through the through-hole for pressure relief, thereby reducing the air pressure within the shell and effectively preventing the lithium battery from exploding. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Figure 1 It is a schematic diagram of the internal structure of a lithium battery.

[0008] Figure 2 It is a schematic diagram of the external structure of a lithium battery.

[0009] Figure 3 It is a partial structural diagram of a lithium battery structure.

[0010] Figure 4 It is a structural diagram of the cap assembly.

[0011] Figure 5 It is a schematic diagram of the exploded structure of the cap assembly.

[0012] Figure 6 It is a schematic diagram of circuit board processing. DETAILED DESCRIPTION

[0013] like Figure 1-3, a lithium battery structure, including a steel shell 1, a lithium battery core 2 installed in the steel shell, and a cap assembly 3 covering the top of the steel shell; the cap assembly includes a circuit board 31 with a voltage conversion function, a metal ring 32 sealed and connected to the top of the steel shell is arranged at the bottom or periphery of the circuit board, and a positive electrode assembly 33 fixedly installed above the circuit board; the positive pole of the core 2 is connected to the positive electrode lead-in end of the circuit board circuit, and the negative pole of the core 2 is electrically connected to the steel shell 1; the steel shell 1 is in contact with the metal ring 32 and is electrically conductive, the metal ring 32 is connected to the negative electrode lead-in end of the circuit board 31, and the positive electrode assembly 33 is connected to the positive electrode output end of the circuit board; a through hole 34 is also provided on the cap assembly 3 to communicate with the inner cavity of the steel shell, and an explosion-proof valve 4 is installed in the through hole 34, and the explosion-proof valve 4 seals the through hole 34 when the pressure inside the steel shell is normal, and opens the through hole when the pressure inside the steel shell is high. In this lithium battery structure, the core is placed directly inside the steel shell, and the cap assembly is placed on top of the steel shell, sealing the core inside the steel shell. Through the through-hole in the middle of the cap assembly, the sealed internal space of the steel shell can be evacuated and electrolyte can be injected to form a battery cell. There is no soft pack - there will be no gap between the soft pack - and the steel shell, which can fully utilize the inner cavity of the steel shell, thereby increasing the battery capacity. In addition, the through-hole of the cap assembly is also equipped with an explosion-proof valve, which can release the pressure when the pressure inside the steel shell is too high, thereby ensuring the safety of the battery.

[0014] The lithium battery structure, such as Figure 2 The steel shell 1 can be cylindrical in shape, and the positive electrode assembly 33 fixed above the circuit board 31 in the cap assembly 3 can be a cylindrical positive electrode with the same shape as the dry cell positive electrode, making the overall lithium battery shape consistent with that of a conventional cylindrical dry cell. The operating voltage platform of the lithium battery cell is 3.7V, and the circuit board is equipped with a step-down circuit, which converts the high voltage of the lithium battery cell to 1.5V, making it suitable for applications in cylindrical dry cells and enabling replacement of dry cells.

[0015] The explosion-proof valve 4, as Figure 3 Figure 4 shows a tubular explosion-proof metal tube 41, which is embedded in the through-hole 34 of the cap assembly and sealed from the outside. An explosion-proof bead 42 is installed within the hole of the explosion-proof metal tube 41, forming an interference fit with the hole to seal the inside and outside of the hole. If the abnormal pressure inside the battery reaches a certain level, the bead will be ejected from the explosion-proof metal tube, defusing the battery interior and preventing explosion.

[0016] In order to prevent the circuit components on the lower side of the circuit board from contacting the electrolyte, the circuit board 31 of the cap assembly 3 can be filled with plastic between the inner side of the metal ring 32 and the explosion-proof valve 4 to form a plastic block 5 to wrap the circuit components, as shown in FIG3 .

[0017] Circuit elements may be provided on both the upper and lower sides of the circuit board 31, such as Figure 4, the circuit components on both the upper and lower sides of the circuit board can be filled with plastic to form a sealed plastic block to better protect the circuit components. A plastic hole 35 can be provided on the circuit board. During the injection molding of the circuit board, the plastic can flow from one side to the other through the plastic hole, so that the upper and lower sides of the circuit board can be injection molded and encapsulated on one side at the same time, simplifying the process, reducing processing costs and improving production efficiency.

[0018] The outer diameter of the metal ring 32 can be slightly smaller than the outer diameter of the circuit board 31, and is fixed to the lower side of the circuit board through the patch process. With this structure, when multiple circuit boards are simultaneously patched on the same PCB board, after the upper and lower circuit boards are injection molded and potted, each circuit board can be conveniently punched down directly from the upper side of the PCB board, making the processing more convenient. Figure 5 .

[0019] The positive electrode assembly can be in the shape of a cap, with its bottom edge fixed on the circuit board and connected to the positive output terminal of the circuit board; its top is opposite to the through hole of the circuit board, and a vent hole is provided on its side wall.

[0020] The positive electrode assembly 33, such as Figure 3 、 Figure 4 、 Figure 6 , and may also include a positive cap 331 serving as the battery's positive electrode and a light-transmitting cover 332 at the bottom of the positive cap. The light-transmitting cover 332 is dome-shaped, with its bottom edge fixed to the circuit board and connected to the circuit board's positive output terminal. It has a raised platform 333 in the center, with a through-hole 334 positioned in the middle of the platform, facing the through-hole 34 of the circuit board. The positive cap 331 is fixed to the platform of the light-transmitting cover 332, shielding the through-hole, and has ventilation holes 335 positioned on its sidewalls. The portion of the circuit board within the light-transmitting cover 332 can be equipped with an indicator light for indicating the battery's operating status. A light-transmitting window 336 is positioned in the raised portion of the light-transmitting cover connecting the platform to the bottom edge, through which the indicator light is transmitted. This structure allows the battery to intuitively indicate its operating status, allowing the user to intuitively understand the battery's status.

Claims

1. A lithium battery structure, comprising a steel shell (1), characterized in that: A reel (2) of a lithium battery is installed in a steel shell, and a cap assembly (3) is covered on the top of the steel shell; the cap assembly includes a circuit board (31) with a voltage conversion management function, a metal ring (32) is provided on the bottom or periphery of the circuit board and is sealed and connected to the end of the steel shell, and a positive electrode assembly (33) is fixedly installed on the top of the circuit board; the positive electrode of the reel (2) is connected to the positive electrode lead-in end of the circuit board circuit through an explosion-proof metal tube (41), and the negative electrode of the reel (2) is electrically connected to the steel shell (1); the steel shell (1) is in contact with the metal ring (32) and is electrically conductive, the metal ring (32) is connected to the negative electrode lead-in end of the circuit board (31), and the positive electrode assembly (33) is connected to the positive electrode output end of the circuit board; a through hole (34) is also provided on the cap assembly (3) and is connected to the inner cavity of the steel shell, and an explosion-proof valve (4) is installed in the through hole (34), and the explosion-proof valve (4) seals the through hole (34) when the pressure inside the steel shell is normal and opens the through hole when the pressure inside the steel shell is high.

2. The lithium battery structure according to claim 1, characterized in that: The steel shell (1) is cylindrical in shape, and the positive electrode assembly (33) fixedly mounted above the circuit board (31) in the cap assembly (3) is a columnar positive electrode having the same shape as the positive electrode of a dry cell, so that the shape of the entire lithium battery is consistent with that of a conventional cylindrical dry cell.

3. The lithium battery structure according to claim 1 or 2, characterized in that: The explosion-proof valve (4) comprises a tubular explosion-proof metal tube (41), which is embedded in the through hole (34) of the cap assembly and sealed on the outside with the through hole. An explosion-proof bead (42) is installed in the tube hole of the explosion-proof metal tube (41), and the explosion-proof bead (42) is interference-fitted with the tube hole to seal the inside and outside of the tube hole.

4. The lithium battery structure according to claim 1 or 2, characterized in that: The circuit board (31) is filled with plastic between the inner side of the metal ring (32) and the explosion-proof valve (4) to form a plastic block (5) that wraps the circuit components to form an airtight barrier structure.

5. The lithium battery structure according to claim 4, characterized in that: The top surface of the circuit board (31) is also filled with plastic to form a plastic block (5) to seal and wrap the circuit components.

6. The lithium battery structure according to claim 5, characterized in that: Plastic flow-through holes (35) are provided on the circuit board.

7. The lithium battery structure according to claim 1, characterized in that: The outer diameter of the metal ring (32) is slightly smaller than the outer diameter of the circuit board (31), and is fixed to the bottom side of the circuit board through a patch process.

8. The lithium battery structure according to claim 1 or 2, characterized in that: The positive electrode assembly (33) is cap-shaped, with its bottom edge fixed on the circuit board and connected to the positive output end of the circuit board; its top is opposite to the through hole of the circuit board, and a vent hole is provided on its side wall.

9. The lithium battery structure according to claim 1 or 2, characterized in that: The positive electrode assembly (33) includes a positive electrode cap (331) serving as the positive electrode of the battery and a light-transmitting cover (332) at the bottom of the positive electrode cap. The light-transmitting cover (332) is in the shape of a round cap, and its bottom edge is fixed on the circuit board and connected to the positive electrode output terminal of the circuit board. The center of the light-transmitting cover is provided with an arched platform (333), and the center of the platform is provided with a through hole (334) opposite to the through hole (34) of the circuit board. The positive electrode cap (331) is fixedly connected to the platform of the light-transmitting cover (332) to block the through hole, and a vent (335) is provided on the side wall thereof. The portion of the circuit board inside the light-transmitting cover (332) can be installed with an indicator light for indicating the working status of the battery. The light-transmitting cover is provided with a light-transmitting window (336) for transmitting the indicator light at the arched portion connecting the platform and the bottom edge.

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