Cylindrical battery cell and installation method

Abstract

The invention relates to the technical field of battery structures, in particular to a cylindrical battery cell and a mounting method. The cylindrical battery cell comprises a shell, a positive electrode end cover, a negative electrode end cover and a roll core structure, a containing cavity used for containing the roll core structure is formed in the shell. The positive electrode end cover is installed at one end of the shell. And the cathode end cover is arranged at the other end of the shell. And the positive electrode end cover and the negative electrode end cover seal the end part of the placing cavity. And the roll core structure is embedded in the placing cavity. A winding through hole is formed in the middle of the winding core structure. And a supporting pipe is arranged in the winding through hole. And one end of the supporting tube is mounted on the negative end cover. The two ends of the supporting pipe are coated with insulating films. According to the cylindrical battery cell, an existing battery cell structure is optimized, the supporting pipe is used for internally supporting the roll core structure, the problem of mechanical stress generated by the roll core structure in the charging and discharging process is solved, the stability of the roll core structure is guaranteed, the heat conduction capacity of the shell is improved, and the service life of a battery is prolonged.

Description

Technical Field

[0001] The present invention relates to the technical field of battery structures, and in particular to a cylindrical battery core and an installation method thereof. Background Art

[0002] The structural design of cylindrical cells is designed to provide efficient energy storage and release while ensuring safety and stability. Cylindrical cells generally include positive electrodes, negative electrodes, electrolytes, separators and casings. The positive electrode is usually made of lithium compounds (such as lithium cobalt oxide, lithium iron phosphate), which can embed and deintercalate lithium ions to achieve the storage and release of electrical energy. The negative electrode is usually made of graphite or other carbon materials, which can also embed and deintercalate lithium ions. During charging, lithium ions move from the positive electrode to the negative electrode and embed into it; during discharge, lithium ions return from the negative electrode to the positive electrode. The electrolyte is responsible for transporting ions between the positive and negative electrodes, and also serves to isolate the positive and negative electrodes to prevent short circuits. The separator is usually made of polymer materials with good chemical and thermal stability.

[0003] Among them, the positive electrode, the separator and the negative electrode are stacked in sequence and then wound into a tight core structure. The core structure enables a large amount of electrode materials to be compactly accommodated inside the battery, thereby providing a higher energy density. For example, a battery core is disclosed in Chinese patent document CN109659480A. The battery core includes a core body with a hollow inner hole, and the core body includes a first separator, a negative electrode sheet, a second separator and a positive electrode sheet stacked and wound in sequence, the positive electrode sheet includes a positive metal substrate, a positive electrode ear and a positive electrode coating coated on the positive metal substrate, and the negative electrode sheet includes a negative metal substrate, a negative electrode ear and a negative electrode coating coated on the negative metal substrate.

[0004] However, in actual use, the cylindrical battery cell with a core structure described above has a hollow inner hole and lacks support inside. During charging, the embedding of lithium ions into the negative electrode material may cause the negative electrode to expand. If the expansion is excessive, the core structure may be damaged. In addition, the positive electrode material may also change in volume during the charge and discharge cycle, resulting in a lack of stability in the core structure. As a result, during the charge and discharge process, the mechanical stress generated by the volume change of the core structure may cause the electrode material to peel off, thereby greatly affecting the service life of the battery. In addition, during high-current discharge or fast charging, the temperature distribution inside the battery casing is uneven, and heat is easily accumulated in the hollow inner hole, leading to local overheating problems. The accumulated heat is difficult to transfer to the outside through the side wall of the casing in the hollow inner hole, thereby affecting the battery use effect. Summary of the invention

[0005] The purpose of the present invention is to provide an improved structure for the use of cylindrical battery cells, so as to enhance the stability of the core structure, improve the thermal conductivity of the shell, and extend the service life of the battery.

[0006] To achieve the above-mentioned object, the present invention provides a cylindrical battery cell, comprising a shell, a positive terminal cover, a negative terminal cover and a winding core structure; The housing is provided with a placement cavity for accommodating the winding core structure, the positive terminal cover is installed at one end of the housing, and the negative terminal cover is installed at the other end of the housing, and the positive terminal cover and the negative terminal cover form a seal on the end of the placement cavity; The winding core structure is embedded in the placement cavity, a winding through hole is provided in the middle of the winding core structure, and a support tube is provided in the winding through hole; One end of the support tube is mounted on the negative terminal cover, and both ends of the support tube are covered with an insulating film.

[0007] Among them, the support tube is arranged in the winding through hole of the core structure. On the one hand, it is convenient to play the role of internal support for the core structure, which is beneficial to alleviate the mechanical stress problem generated by the core structure during the charging and discharging process, and ensure the stability of the core structure; on the other hand, it is convenient for the negative end cap to exchange heat with the inside of the core structure through the support tube, which is beneficial to quickly conduct the heat generated by the battery cell during charging and discharging from the negative end cap, avoiding heat accumulation, and also conducive to introducing the heat used to heat the battery cell from the negative end cap into the winding through hole.

[0008] Preferably, the negative terminal cover is provided with a liquid injection hole, the liquid injection hole is connected to the support tube, and a liquid injection plug is provided in the liquid injection hole. In this way, the liquid injection hole is used to inject electrolyte into the placement cavity, and the liquid injection plug is used to seal the liquid injection hole. The liquid injection hole is also convenient for replenishing or replacing electrolyte in the cylindrical battery cell, which is conducive to restoring the performance of the battery cell and further extending the service life.

[0009] Preferably, a guide hole is provided on the side wall of the support tube. In this way, the guide hole is used to facilitate the electrolyte to smoothly enter the placement cavity through the support tube, which is conducive to the uniform distribution of the electrolyte in the placement cavity, so that the electrolyte has better fluidity in the placement cavity, which is conducive to enhancing the transmission speed of ions, thereby improving the use effect of the battery cell.

[0010] Preferably, the length of the support tube is greater than one-half of the length of the winding core structure, and the length of the support tube is less than two-thirds of the length of the winding core structure. This arrangement facilitates the support tube to ensure the support strength of the winding core structure while effectively avoiding the end of the support tube from contacting the positive terminal cover, further ensuring the stability of the cylindrical battery cell.

[0011] Preferably, the core structure comprises a positive electrode sheet, a separator and a negative electrode sheet, and the positive electrode sheet, the separator and the negative electrode sheet are stacked in sequence and wound to form the core structure.

[0012] Preferably, a positive current collecting disk is arranged between the positive terminal cover and the winding core structure, the positive current collecting disk is connected to the positive electrode sheet on the end surface of the winding core structure, and an insulating sleeve is arranged between the positive current collecting disk and the shell.

[0013] Preferably, a negative electrode current collecting disk is arranged between the negative terminal cover and the winding core structure, and the negative electrode current collecting disk is connected to the negative electrode sheet at the end surface of the winding core structure.

[0014] Preferably, an explosion-proof valve is provided on the positive terminal cover. In this way, the explosion-proof valve is used to maintain the pressure in the placement chamber within a safe range, further improving the safety of the cylindrical battery cell.

[0015] Another aspect of the present invention further provides a method for installing the cylindrical battery cell, comprising the following steps: Shell preparation: First, prepare a cylindrical shell, which has a placement cavity designed inside to accommodate the winding core structure; End cap installation: Install the positive end cap on one end of the shell and the negative end cap on the other end of the shell. These two end caps seal the ends of the placement cavity to ensure the sealing of the battery cell. Embedding the core structure: embed the core structure into the placement cavity, and a winding through hole is provided in the middle of the core structure for installing the support tube; Support tube installation: A support tube is arranged in the winding through hole of the winding core structure, and one end of the support tube is installed on the negative terminal cover, ensuring that both ends are covered with an insulating film to prevent electrical short circuit; Among them, the support tube not only plays an internal supporting role for the core structure, relieves the mechanical stress generated by the core structure during the charging and discharging process, and ensures the stability of the core structure; it also facilitates the heat exchange between the negative terminal cap and the inside of the core structure through the support tube.

[0016] Compared with the prior art, a cylindrical battery cell and installation method provided by the present invention have the following outstanding substantial features and significant progress: the cylindrical battery cell is provided with a support tube in the winding through hole of the core structure, which optimizes the existing battery cell structure, and utilizes the support tube to play an internal supporting role for the core structure, which is beneficial to alleviating the mechanical stress problem generated by the core structure during the charging and discharging process and ensures the stability of the core structure. At the same time, the support tube is connected to the negative terminal cover, and the negative terminal cover exchanges heat with the inside of the core structure through the support tube, which is beneficial to quickly conduct the heat generated by the battery cell during charging and discharging from the negative terminal cover, avoiding heat accumulation, and also beneficial to conduct the heat used to heat the battery cell from the negative terminal cover into the winding through hole, thereby improving the thermal conductivity of the shell and extending the service life of the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a schematic diagram of the assembly structure of a cylindrical battery cell in an embodiment of the present invention.

[0018] Figure 2 It is a schematic diagram of the assembly structure of the support tube and the negative terminal cover in an embodiment of the present invention.

[0019] Figure 3 Schematic diagram of the structure of the support tube in an embodiment of the present invention.

[0020] Figure numerals: 1. Shell; 2. Positive terminal cover; 3. Negative terminal cover; 4. Winding core structure; 5. Support tube; 6. Insulating film; 7. Liquid injection hole; 8. Liquid injection plug; 9. Guide hole; 10. Positive current collecting plate; 11. Insulating sleeve; 12. Negative current collecting plate; 13. Explosion-proof valve. DETAILED DESCRIPTION

[0021] The specific embodiments of the present invention are described in detail below with reference to the accompanying drawings.

[0022] like Figure 1-Figure 3 As shown, a cylindrical battery cell is proposed in an embodiment of the present invention, aiming to improve the stability of the core structure, increase the thermal conductivity of the shell, and extend the service life of the battery.

[0023] The core of existing cylindrical battery cells has a hollow inner hole and lacks internal support. During charging, lithium ions embedded in the negative electrode material may cause the negative electrode to expand. If the expansion is excessive, the core structure may be damaged. In addition, the positive electrode material may also change in volume during the charge and discharge cycle, resulting in a lack of stability in the core structure.

[0024] A cylindrical battery cell proposed in an embodiment of the present invention is provided with a support tube 5 in the winding through hole of the winding core structure 4, which optimizes the existing battery cell structure. The support tube 5 is used to play the role of internal support for the winding core structure 4, which is conducive to alleviating the mechanical stress problem generated by the winding core structure 4 during the charging and discharging process, and ensures the stability of the winding core structure 4. At the same time, the support tube 5 is connected to the negative terminal cover 3, and the negative terminal cover 3 exchanges heat with the inside of the winding core structure 4 through the support tube 5, which is conducive to quickly exporting the heat generated by the battery cell during charging and discharging from the negative terminal cover 3, avoiding heat accumulation. In addition, it is also conducive to introducing the heat used to heat the battery cell from the negative terminal cover 3 into the winding through hole, thereby improving the thermal conductivity of the shell 1 and extending the service life of the battery.

[0025] like Figure 1 As shown, a cylindrical battery cell includes a shell 1, a positive terminal cover 2, a negative terminal cover 3 and a winding core structure 4. The interior of the shell 1 is provided with a placement cavity for accommodating the winding core structure 4. The positive terminal cover 2 is installed at one end of the shell 1. The negative terminal cover 3 is installed at the other end of the shell 1. The positive terminal cover 2 and the negative terminal cover 3 form a closure on the end of the placement cavity. For example, the positive terminal cover 2 and the negative terminal cover 3 are both sealed with the shell 1 by welding.

[0026] like Figure 1 Combination Figure 2 As shown, the winding core structure 4 is embedded in the placement cavity. A winding through hole is provided in the middle of the winding core structure 4, and a support tube 5 is provided in the winding through hole. One end of the support tube 5 is mounted on the negative terminal cover 3. Both ends of the support tube 5 are coated with an insulating film 6. The insulating film 6 is used to enhance the insulation performance inside the battery cell and reduce the risk of short circuit.

[0027] The roll core structure 4 includes a positive electrode sheet, a separator and a negative electrode sheet, which are stacked in sequence and wound to form the roll core structure 4. In this way, the roll core structure 4 enables a large amount of electrode materials to be compactly accommodated inside the battery, thereby providing a higher energy density.

[0028] For example, the length of the support tube 5 is greater than one-half of the length of the winding core structure 4, and the length of the support tube 5 is less than two-thirds of the length of the winding core structure 4. This arrangement facilitates the support tube 5 to ensure the support strength of the winding core structure 4, while effectively avoiding the end of the support tube 5 from contacting the positive terminal cover 2, further ensuring the stability of the cylindrical battery cell.

[0029] like Figure 1 As shown, a positive current collector disk 10 is arranged between the positive terminal cover 2 and the winding core structure 4. The positive current collector disk 10 is connected to the positive electrode sheet on the end face of the winding core structure 4. An insulating sleeve 11 is arranged between the positive current collector disk 10 and the shell 1. A negative current collector disk 12 is arranged between the negative terminal cover 3 and the winding core structure 4, and the negative current collector disk 12 is connected to the negative electrode sheet on the end face of the winding core structure 4. In this way, the cylindrical battery cell forms a non-polar ear structure design through the positive current collector disk 10 and the negative current collector disk 12, which is beneficial to reduce the contact resistance inside the battery cell, improve the energy transmission efficiency, and also simplify the assembly and integration process of the battery cell.

[0030] like Figure 2 As shown, the negative terminal cover 3 is provided with an injection hole 7. The injection hole 7 is connected to the support tube 5. An injection plug 8 is provided in the injection hole 7. In this way, the injection hole 7 is used to facilitate the injection of electrolyte into the placement cavity, and the injection plug 8 is used to form a seal for the injection hole 7. The injection hole 7 is also convenient for replenishing or replacing the electrolyte of the cylindrical battery cell, which is beneficial to restore the performance of the battery cell and further prolong the service life. In addition, during the electrolyte injection process, the injection hole 7 can also play a role in exhaust, allowing the air inside the placement cavity to be discharged, ensuring that the electrolyte can fully fill the internal space of the battery cell.

[0031] like Figure 3As shown, a guide hole 9 is provided on the side wall of the support tube 5. In this way, the guide hole 9 is used to facilitate the electrolyte to smoothly enter the placement cavity through the support tube 5, which is beneficial to the uniform distribution of the electrolyte in the placement cavity, so that the electrolyte has better fluidity in the placement cavity, which is beneficial to enhance the transmission speed of ions, thereby improving the use effect of the battery cell.

[0032] like Figure 1 As shown, an explosion-proof valve 13 is provided on the positive terminal cover 2. In this way, the explosion-proof valve 13 is used to maintain the pressure in the placement cavity within a safe range, further improving the safety of the use of cylindrical batteries. For example, when the pressure inside the battery cell rises sharply due to overheating, short circuit or other abnormal conditions, the explosion-proof valve 13 will open, allowing high-pressure gas or steam to be quickly discharged, thereby avoiding the battery cell housing 1 from rupturing or exploding. During normal charging and discharging, a small amount of gas, such as hydrogen or oxygen, may be generated inside the battery cell. The explosion-proof valve 13 can prevent these gases from accumulating to dangerous levels and keep the internal pressure of the battery cell within a safe range.

[0033] When a cylindrical battery cell proposed in an embodiment of the present invention is used, the embedded design of the core structure 4 enables it to be well supported and protected in the shell 1, reducing the risk of damage caused by external impact or pressure. The positive terminal cover 2 and the negative terminal cover 3 are respectively installed at both ends of the shell 1, forming a closure for the end of the placement cavity, effectively isolating the external environment, preventing electrolyte leakage and the intrusion of external pollutants, and improving the safety and service life of the battery cell. A support tube 5 is provided in the winding through hole set in the middle of the core structure 4, and both ends of the support tube 5 are coated with an insulating film 6. This design not only provides additional structural support to ensure the stability of the core structure 4, but also the use of the insulating film 6 enhances the insulation performance inside the battery cell and reduces the risk of short circuit.

[0034] The cylindrical battery cell proposed in the embodiment of the present invention makes full use of space, and the compact layout of the winding core structure 4 and the effective use of the support tube 5 enable the battery cell to provide a higher energy density while maintaining a smaller volume. At the same time, due to the standardized structure of the cylindrical battery cells, they are easy to integrate into various devices, such as portable electronic devices, power tools, etc.

[0035] The present invention is not limited to the specific technical solutions described in the above embodiments. In addition to the above embodiments, the present invention may also have other implementation modes. For those skilled in the art, any technical solutions formed by any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A cylindrical battery cell, characterized in that: It comprises a shell (1), a positive terminal cover (2), a negative terminal cover (3) and a winding core structure (4); The housing (1) is provided with a placement cavity for accommodating the winding core structure (4), the positive terminal cover (2) is mounted on one end of the housing (1), and the negative terminal cover (3) is mounted on the other end of the housing (1), and the positive terminal cover (2) and the negative terminal cover (3) form a seal on the end of the placement cavity; The winding core structure (4) is embedded in the placement cavity, a winding through hole is provided in the middle of the winding core structure (4), and a support tube (5) is provided in the winding through hole; One end of the support tube (5) is mounted on the negative terminal cover (3), and both ends of the support tube (5) are covered with an insulating film (6).

2. The cylindrical battery cell according to claim 1, characterized in that: The negative terminal cover (3) is provided with a liquid injection hole (7), the liquid injection hole (7) is connected to the support tube (5), and a liquid injection plug (8) is provided in the liquid injection hole (7).

3. The cylindrical battery cell according to claim 2, characterized in that: A flow guide hole (9) is provided on the side wall of the support tube (5).

4. The cylindrical battery cell according to claim 1, characterized in that: The length of the support tube (5) is greater than half of the length of the winding core structure (4), and the length of the support tube (5) is less than two thirds of the length of the winding core structure (4).

5. The cylindrical battery cell according to claim 1, characterized in that: The winding core structure (4) comprises a positive electrode sheet, a separator and a negative electrode sheet, and the positive electrode sheet, the separator and the negative electrode sheet are stacked in sequence and wound to form the winding core structure (4).

6. The cylindrical battery cell according to claim 1, characterized in that: A positive electrode current collecting disk (10) is arranged between the positive terminal cover (2) and the winding core structure (4); the positive electrode current collecting disk (10) is connected to the positive electrode sheet at the end surface of the winding core structure (4); and an insulating sleeve (11) is arranged between the positive electrode current collecting disk (10) and the housing (1).

7. The cylindrical battery cell according to claim 6, characterized in that: A negative electrode current collecting disk (12) is provided between the negative terminal cover (3) and the winding core structure (4), and the negative electrode current collecting disk (12) is connected to the negative electrode sheet at the end surface of the winding core structure (4).

8. The cylindrical battery cell according to claim 1, characterized in that: An explosion-proof valve (13) is provided on the positive terminal cover (2).

9. The method for installing a cylindrical battery cell according to any one of claims 1 to 8, characterized in that: include: Shell preparation: First, prepare a cylindrical shell, which has a placement cavity designed inside to accommodate the winding core structure; End cap installation: Install the positive end cap on one end of the shell and the negative end cap on the other end of the shell. These two end caps seal the ends of the placement cavity to ensure the sealing of the battery cell. Embedding the core structure: embed the core structure into the placement cavity, and a winding through hole is provided in the middle of the core structure for installing the support tube; Support tube installation: A support tube is arranged in the winding through hole of the winding core structure, and one end of the support tube is installed on the negative terminal cover, ensuring that both ends are covered with an insulating film to prevent electrical short circuit; Among them, the support tube not only plays an internal supporting role for the core structure, relieves the mechanical stress generated by the core structure during the charging and discharging process, and ensures the stability of the core structure; it also facilitates the heat exchange between the negative terminal cap and the inside of the core structure through the support tube.

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