Cylindrical battery sealing device

Abstract

The embodiment of the utility model discloses a cylindrical battery sealing device, a cylindrical battery comprises a shell, the cylindrical battery sealing device is used for sealing an opening of the shell, and the cylindrical battery sealing device comprises a sealing plate used for covering the opening; the side plate is connected to the periphery of the sealing plate and extends along the peripheral side wall in a manner of being perpendicular to the sealing plate; the inner side face, facing the peripheral side wall, of the side plate is provided with a damping component used for being connected with the rolling groove in a clamped mode. According to the technical scheme, at least one cylindrical battery sealing device is provided, and water can be effectively prevented from being introduced into a battery shell in the battery manufacturing period.

Description

TECHNICAL FIELD

[0001] The utility model relates to energy storage equipment technical field more specifically, relate to a cylindrical battery sealing device. BACKGROUND

[0002] In the field of new energy power battery, the application of secondary battery is more and more widely, such as secondary battery (for example, lithium ion battery) can be applied to car, energy storage, mobile phone, tablet computer, wearable device, mobile power supply, electronic cigarette, digital product, electric tool, power device, energy storage device and other electronic devices. One of the secondary battery is cylindrical battery, cylindrical battery includes shell and electrode assembly, electrode assembly includes positive pole piece, first diaphragm, negative pole piece and second diaphragm, and is wound into electrode assembly after mutual stacking, and then is packaged in shell. However, the existing cylindrical battery still needs to be further improved in some aspects. SUMMARY

[0003] In view of the problems in the related art, the utility model aims at providing a cylindrical battery sealing device, which can at least avoid the introduction of moisture into the battery shell during the manufacture of the cylindrical battery.

[0004] To achieve the above-mentioned purpose, the embodiment of the present application provides a cylindrical battery sealing device, wherein the cylindrical battery includes a shell and an electrode assembly, the shell includes an end wall and a circumferential side wall surrounding the end wall, one end of the circumferential side wall opposite to the end wall forms an opening, the circumferential side wall is provided with a rolling groove protruding inwardly adjacent to the opening, and the electrode assembly is located between the end wall and the rolling groove. The cylindrical battery sealing device is used for sealing the opening of the shell, and the cylindrical battery sealing device includes: a sealing plate used for covering the opening; a side plate connected to the periphery of the sealing plate and extending along the circumferential side wall perpendicular to the sealing plate; wherein the side plate is provided with a damping member at the inner side of the circumferential side wall for clamping the rolling groove.

[0005] In some embodiments, the side plate is embedded with a magnetic attraction member for adsorbing the circumferential side wall.

[0006] In some embodiments, the magnetic attraction member is located on the side away from the sealing plate of the damping member.

[0007] In some embodiments, the magnetic attraction member is exposed by the inner side of the side plate, and the surface of the magnetic attraction member facing the circumferential side wall is coplanar with the inner side of the side plate.

[0008] In some embodiments, the damping member includes a spring partially embedded in the side plate, and a clamping element connected to the spring, the clamping element protruding from the inner side of the side plate.

[0009] In some embodiments, the surface of the sealing plate facing the opening is used to contact the end of the circumferential side wall at the opening.

[0010] In some embodiments, a through hole is provided in the sealing plate, the through hole penetrates the sealing plate in the thickness direction of the sealing plate, and a one-way exhaust valve is provided in the through hole, the exhaust valve is used to exhaust gas outside the shell when the air pressure inside the shell is greater than a predetermined air pressure value.

[0011] In some embodiments, the exhaust valve includes a drop device movable in the thickness direction to open and close the exhaust valve.

[0012] In some embodiments, the through hole is located at the center of the sealing plate.

[0013] In some embodiments, the shell is a nickel-plated steel shell.

[0014] The beneficial technical effects of the utility model lie in:

[0015] The cylindrical battery sealing device of the application can guarantee the fit of the cylindrical battery sealing device and the rolling groove through the clamping of the damping member and the rolling groove, the damping member can be pressed to the specified position and tightly matched with the groove depth part of the rolling groove to play a sealing role, the overall cylindrical battery sealing device and the shell can be guaranteed to be sealed, water can be prevented from being introduced into the shell during the battery process, the water content introduced during the battery process can be effectively reduced, and the problem of gas phase corrosion can be avoided in the later process, and the blackening phenomenon in the shell can be improved. The cylindrical battery sealing device further comprises a magnetic attraction member, and the magnetic force provided by the magnetic attraction member can ensure that the side plate is attracted to the circumferential wall, and can ensure that the cylindrical battery sealing device seals the shell. In addition, the one-way exhaust valve can be used for pressure relief during immersion, and water can be prevented from entering the shell. BRIEF DESCRIPTION OF DRAWINGS

[0016] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed to be used in the embodiment or prior art description will be briefly introduced below. Obviously, the drawings in the following description are some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative labor.

[0017] Figure 1 is a schematic diagram of the shell of the cylindrical battery after the rolling groove is formed.

[0018] Figure 2 is a schematic diagram of the overall cylindrical battery sealing device according to the application after the shell is sealed.

[0019] Figure 3 is a schematic diagram of the overall cross section of the cylindrical battery sealing device according to the application after the shell is sealed.

[0020] Figure 4Figure 8 is a partial enlarged sectional view of the damping member and the magnetic attraction member in Figure 7.

[0021] Figure 5 Figure 9 is a partial enlarged sectional view of the damping member and the magnetic attraction member in Figure 8. Figure 4 DETAILED DESCRIPTION

[0022] For better understanding of the spirit of the embodiments of the present application, the following further describes the embodiments of the present application in combination with some preferred embodiments of the present application.

[0023] The embodiments of the present application will be described in detail below. In the entire description of the present application, the same or similar components and components having the same or similar functions are denoted by similar reference numerals. The embodiments described herein with reference to the accompanying drawings are illustrative in nature, diagrammatic in nature and for providing a basic understanding of the present application. The embodiments of the present application should not be interpreted as a limitation of the present application.

[0024] As used herein, the terms "approximately", "substantially", "essentially", and "about" are used to describe and account for small variations. When used in connection with an event or circumstance, the terms can refer to instances in which the event or circumstance occurs exactly, as well as instances in which the event or circumstance occurs approximately.

[0025] In the present specification, unless specifically specified or limited, relative terms such as "central", "longitudinal", "lateral", "front", "rear", "right", "left", "internal", "external", "lower", "upper", "horizontal", "vertical", "higher", "lower", "above", "below", "top", "bottom", and derivatives thereof (e.g. "horizontally", "downwardly", "upwardly", etc.) should be interpreted to refer to the orientation of the described or depicted direction in the discussion or in the accompanying drawings. These relative terms are used only for the convenience of description and do not require the present application to be constructed or operated in a particular orientation.

[0026] For the convenience of description, "first", "second", "third", etc. can be used herein to distinguish different components of a figure or a series of figures. "First", "second", "third", etc. are not intended to describe the corresponding components.

[0027] ​Cylindrical batteries usually use a nickel-silicon carbon material system, which can greatly improve the energy density and capacity of the battery monomer. At the same time, the shell of the cylindrical battery usually adopts a steel shell (such as SPCC steel), and the surface of the steel shell is subjected to overall chemical nickel plating treatment to prevent corrosion. However, as customer demand becomes higher (such as high-temperature storage, high-temperature self-discharge, long calendar life, etc.), this high-nickel system brings more serious internal blackening of the steel shell. The internal blackening of the steel shell can cause: 1) chemical corrosion occurs due to internal blackening of the steel shell, resulting in a sharp drop in voltage and failure of the battery cell; 2) internal blackening of the shell causes the battery to produce more by-products, resulting in poor cycle life; 3) internal blackening of the shell causes the production of foreign matter such as by-products, which aggravates self-discharge and easily induces safety problems. The industry has also proposed many solutions to this problem, such as: 1) small current pre-charging before liquid injection to consume moisture; 2) strict control of moisture in the process to prevent the side reaction of moisture and electrolyte; 3) using electrode assembly baking (Baking) to strictly control the moisture inside the electrode assembly; 4) adding water and acid removal additives to the electrolyte to remove the moisture inside the battery cell.

[0028] For high-nickel systems, moisture control in the process is particularly important. For the current negative pressure formation process, a small current pre-charging is performed after the first liquid injection, and then a high-temperature soaking process is performed at 45°C for 48 hours with a cap. Although there is environmental control during this period, there is still a risk of moisture absorption (especially after liquid injection). Therefore, additional battery sealing devices are needed to seal the process for moisture control. At the same time, gas production during the high-temperature soaking process also needs to be removed. The existing battery sealing devices for the transfer process cannot effectively seal and vent, and the battery sealing devices will have corrosion problems after long-term use. Therefore, a battery sealing device for open batteries is needed to ensure sealing and pressure relief during soaking, thereby improving the performance and product quality of the battery.

[0029] In view of the above problems in the prior art, embodiments of the present application provide a cylindrical battery sealing device. Figure 1 is a schematic diagram of the shell of the cylindrical battery after the formation of the rolling groove. Figure 2 is a schematic diagram of the cylindrical battery sealing device according to the present application after sealing the shell. Figure 3 is a schematic diagram of the cylindrical battery sealing device according to the present application after sealing the shell.

[0030] In combination with Figures 1 to 3 As shown in the figure, the present application provides a cylindrical battery sealing device 100 for sealing the shell 200 of a cylindrical battery. In some embodiments, the shell 200 is a nickel-plated steel shell.

[0031] The shell 200 can specifically include an end wall 261 and a circumferential side wall 262 surrounding the end wall 261. An end of the circumferential side wall 262 opposite to the end wall 261 forms the opening 205. The circumferential side wall 262 is provided with a roll groove 210 protruding inwardly of the shell at a position adjacent to the opening 205. A direction from the end wall 261 to the opening 205 is a height direction of the cylindrical battery. The electrode assembly 160 of the cylindrical battery is located between the end wall 261 and the roll groove 210 to define a movement of the electrode assembly 160 in the height direction.

[0032] The electrode assembly 160 is mainly formed by sequentially laminating and winding a positive electrode tab, a negative electrode tab, and a separator between the positive electrode tab and the negative electrode tab. The electrode assembly 160 formed by winding has a positive electrode tab and a negative electrode tab on opposite sides in the height direction, respectively. In some embodiments, the negative electrode tab faces the opening 205, and the positive electrode tab faces the end wall 261.

[0033] In some embodiments, the positive electrode tab can include a positive current collector and a positive coating region coated on a part of a surface of the positive current collector. The positive coating region is a positive active material layer formed by coating of a positive active material. A part of the positive current collector not covered by the positive coating region constitutes the positive electrode tab. The negative electrode tab can include a negative current collector and a negative coating region coated on a part of a surface of the negative current collector. The negative coating region is a negative active material layer formed by coating of a negative active material. A part of the negative current collector not covered by the negative coating region constitutes the negative electrode tab.

[0034] Taking a lithium ion battery as an example, a material of the positive current collector can be aluminum, the positive coating region can include a positive active material, and the positive active material can be lithium cobaltate, lithium iron phosphate, ternary lithium, or lithium manganate, etc. A material of the negative current collector can be copper. The negative coating region can include a negative active material, and the negative active material can be carbon or silicon, etc. A material of the separator can be PP or PE, etc.

[0035] In some embodiments, a manufacturing method of the cylindrical battery can include the following steps:

[0036] A winding step of laminating and winding the positive electrode tab, the separator, and the negative electrode tab to form the electrode assembly, the positive electrode tab and the negative electrode tab constituted by the uncoated parts of the positive current collector of the positive electrode tab and the negative current collector of the negative electrode tab. Then the positive electrode tab and the negative electrode tab can be bent along a radial direction of the electrode assembly. Then the positive current collector and the negative current collector can be respectively welded to the bent positive electrode tab and the negative electrode tab.

[0037] A shell-into step of installing the electrode assembly 160 with the welding completed into the shell 200 from the opening 205. The way of installing the electrode assembly 120 in this step is not limited, for example, the electrode assembly 120 can be installed manually or by a mechanical hand.

[0038] The adapter piece welding step welds the adapter piece of the negative current collector plate to the peripheral side wall 262 of the shell 200. Then, the pole can be installed through the end wall 261, and the pole is connected to the positive current collector plate.

[0039] The rolling step, in some embodiments, rolls the outer periphery of the peripheral side wall 262 of the shell 200 to form a rolling groove 113 recessed radially toward the center of the shell 200, so as to limit the movement of the electrode assembly 160 in the height direction.

[0040] The liquid injection step injects electrolyte into the shell 200. The injection method of the electrolyte is not limited, and can be selected to be injected through the opening 205 or through the liquid injection hole provided on the end wall 261. Preferably, in the present embodiment, the electrolyte is injected through the opening 205, which reduces the process of opening the liquid injection hole on the end wall 261, and can directly use the existing opening 205 for injection, thereby simplifying the process and reducing the cost.

[0041] The formation step is to charge the battery for the first time, which is to activate the battery. The formation has a very important influence on the lithium ion battery, which affects the cycle and safety performance of the battery, and directly determines the performance of the battery.

[0042] The sealing step: the cover plate of the cylindrical battery is sealed and installed on the opening 205. The mechanical sealing process can be used to form a hem portion on the end portion 209 of the opening 205 of the peripheral side wall 262, so as to seal and install the cover plate of the cylindrical battery on the opening 205 of the shell 200. After the sealing step, the aging step, the static step and the capacity grading step can be performed in sequence.

[0043] The formation step before the sealing step can specifically include: a pre-charging step, an immersion step after the pre-charging step, a negative pressure formation step after the immersion step, and a liquid supplementing step after the negative pressure formation step.

[0044] The immersion step is generally a high-temperature immersion process, which is performed at 45℃ for 48 hours. Although there is environmental control during the high-temperature immersion process, there is still a risk of absorbing moisture (especially after liquid injection). Since the sealing step has not been performed at this time, the opening 205 is open. Therefore, the moisture control for this high-temperature immersion process needs to be sealed by the cylindrical battery sealing device 100. The cylindrical battery sealing device 100 can also be used to protect the moisture control inside the cylindrical battery shell in other situations, such as production suspension due to production abnormalities or unqualified environment.

[0045] Figure 4 FIG. 10 is a partial enlarged sectional view of the cylindrical battery sealed by the cylindrical battery sealing device according to the present application. Figure 5 Figure 4 ​FIG. 4 is a partial enlarged sectional view of the damping member and the magnetic attraction member in FIG. 3. FIG. 5 is a partial enlarged sectional view of the damping member and the magnetic attraction member in FIG. 3. Figures 3 to 5 As shown in FIG. 1, the cylindrical battery sealing device 100 can include a sealing plate 120 and a side plate 140 connected to the periphery of the sealing plate 120. The sealing plate 120 is used to cover the opening 205 of the shell 200. The side plate 140 extends perpendicularly to the sealing plate 120 along the peripheral side wall 262 of the shell 200. The inner side of the side plate 140 faces the peripheral side wall 262, and the inner side of the side plate 140 is provided with a damping member 250 for clamping with the rolling groove 210.

[0046] By clamping the damping member 250 with the rolling groove 210, the cylindrical battery sealing device 100 can be guaranteed to fit the rolling groove, and the cylindrical battery sealing device 100 and the deep part of the groove of the rolling groove 210 have a damping function. The damping member 250 can be pressed to a specified position and tightly fit the deep part of the groove of the rolling groove 210 to play a sealing role. The overall cylindrical battery sealing device 100 can be guaranteed to be sealed with the shell, avoiding the introduction of moisture into the shell during the battery process (such as the infiltration process), effectively reducing the water content introduced during the battery process, thereby avoiding the problem of gas phase corrosion in the later process, and improving the blackening phenomenon inside the shell.

[0047] In the embodiment in which the shell is a nickel-plated steel shell, the blackening phenomenon inside the shell is more likely to occur. By providing the damping member 250 in the cylindrical battery sealing device 100 to guarantee the sealing of the shell 200, the blackening phenomenon inside the shell is improved, thereby reducing the risk of chemical corrosion leading to voltage drop and cell failure, prolonging the cycle life, and improving the safety of the cylindrical battery.

[0048] In some embodiments, the number of damping members 250 is at least two, and the two damping members 250 are oppositely arranged in the radial direction of the sealing plate 120. In some embodiments, the damping member 250 includes a spring 251 embedded in the side plate 140 and a clamping element 253 connected to the spring 251. The clamping element 253 protrudes from the inner side of the side plate 140. At least part of the surface of the rolling groove 210 facing the outside of the shell is arc-shaped, and at least part of the surface of the clamping element 253 can be arc-shaped and can cooperate with the arc-shaped switch of the rolling groove 210 to enable the clamping element 253 to clamp with the rolling groove 210. Such a damping member 250 has a simple structure and does not excessively increase the processing difficulty, and can guarantee the sealing effect of the overall cylindrical battery sealing device 100 and the shell 200.

[0049] In some embodiments, when the cylindrical battery sealing device 100 is closed on the opening 205 of the shell 200, the surface of the sealing plate 120 facing the opening 205 is used to contact the end 209 of the peripheral side wall 262 at one end of the opening 205. In this way, the sealing plate 120 can seal the opening 205 of the shell 200 to provide a good sealing effect.

[0050] In some embodiments, the side plate 140 is embedded with a magnetic attraction member 290, such as a magnet, for attracting the peripheral side wall 262 of the shell 200. By providing the magnetic attraction member 290, the magnetic force provided by the magnetic attraction member 290 can ensure that the side plate 140 is attracted to the peripheral side wall 262, thereby ensuring the sealing of the shell 200 by the cylindrical battery sealing device 100.

[0051] In some embodiments, the magnetic attraction member 290 is located on the side of the damping member 250 away from the sealing plate 120, i.e. the magnetic attraction member 290 is closer to the end of the side plate 140 facing away from the sealing plate 120. By providing the magnetic attraction member 290 in this way, it can be more advantageous to avoid moisture entering the inside of the shell through the end of the side plate 140 facing away from the sealing plate 120.

[0052] In some embodiments, the magnetic attraction member 290 is exposed by the inner side of the side plate 140. The surface of the magnetic attraction member 290 facing the peripheral side wall 262 is coplanar with the inner side of the side plate 140. By exposing the magnetic attraction member 290 by the inner side of the side plate 140, the magnetic attraction effect is better and the sealing effect is also better.

[0053] In some embodiments, the sealing plate 120 is provided with a through hole 123 extending through the thickness of the sealing plate 120, and the exhaust valve 150 is arranged in the through hole 123. The exhaust valve 150 is a one-way exhaust valve, which is used to exhaust gas to the outside of the shell when the gas pressure inside the shell is greater than a predetermined gas pressure value, so as to perform pressure relief. When the gas pressure inside the shell is not greater than the predetermined gas pressure value, the exhaust valve can remain closed to isolate moisture. In some embodiments, the predetermined gas pressure value can be in the range of 0.05Mpa-0.25Mpa. Since the electrode assembly will produce gas during the soaking process, by providing a one-way exhaust valve 150, it can be used for pressure relief during soaking, while also avoiding the entry of moisture into the shell.

[0054] In some embodiments, the through hole 123 is located at the center of the sealing plate 120, that is, the through hole can be arranged coaxially with the shell. The electrode assembly after winding will have a winding center hole at the center, which can be used as the main exhaust passage for gas produced by the electrode assembly. By arranging the through hole 123 at the center of the sealing plate 120, the exhaust valve 150 can be aligned with the winding center hole of the electrode assembly in the height direction, so as to more advantageously perform pressure relief.

[0055] In some embodiments, the exhaust valve 150 comprises a movable falling device (not shown) in the thickness direction to open and close the exhaust valve. During the process of infiltration, the exhaust valve controls the opening of the exhaust valve according to the amount of gas generated inside the shell, and then performs the exhaust. After the exhaust is completed, the exhaust valve is automatically closed under the action of the damper to play the role of isolating moisture and controlling the introduction of moisture.

[0056] In addition, after the negative pressure formation, the exhaust valve 150 can also be kept in an open state for small hole liquid supplementing, to prevent moisture introduction caused by liquid supplementing through the opening 205. The exhaust valve can be kept in a closed state to play a sealing role before the cell is in the sealing step and during the transportation process.

[0057] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can be variously changed and modified. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A cylindrical battery sealing device, characterized in that, A cylindrical battery includes a housing and an electrode assembly. The housing includes an end wall and a peripheral side wall surrounding the end wall. An opening is formed at one end of the peripheral side wall opposite to the end wall. An inwardly protruding groove is provided on the peripheral side wall adjacent to the opening. The electrode assembly is located between the end wall and the groove. A cylindrical battery sealing device is used to seal the opening of the housing. The cylindrical battery sealing device includes: A sealing plate is used to cover the opening; Side plate, connected to the periphery of the sealing plate, and extending perpendicularly to the sealing plate along the periphery sidewall; The side plate is provided with a damping member on the inner side facing the peripheral wall for engaging with the groove.

2. The cylindrical battery sealing device according to claim 1, characterized in that, The side plate is embedded with a magnetic attraction component for adsorbing the peripheral side wall.

3. The cylindrical battery sealing device according to claim 2, characterized in that, The magnetic suction component is located on the side of the damping component away from the sealing plate.

4. The cylindrical battery sealing device according to claim 2, characterized in that, The magnetic attraction member is exposed by the inner surface of the side plate, and the surface of the magnetic attraction member facing the peripheral sidewall is coplanar with the inner surface of the side plate.

5. The cylindrical battery sealing device according to claim 1, characterized in that, The damping member includes a spring partially embedded in the side plate and a snap-fit ​​element connected to the spring, the snap-fit ​​element protruding from the inner surface of the side plate.

6. The cylindrical battery sealing device according to claim 1, characterized in that, The surface of the sealing plate facing the opening is used to contact the end of the peripheral sidewall at one end of the opening.

7. The cylindrical battery sealing device according to claim 1, characterized in that, The sealing plate has a through hole that penetrates the sealing plate in the thickness direction. A one-way exhaust valve is provided in the through hole. The exhaust valve is used to discharge gas to the outside of the housing when the gas pressure inside the housing is greater than a predetermined gas pressure value.

8. The cylindrical battery sealing device according to claim 7, characterized in that, The exhaust valve includes a retraction device movable in the thickness direction to open and close the exhaust valve.

9. The cylindrical battery sealing device according to claim 7, characterized in that, The through hole is located at the center of the sealing plate.

10. The cylindrical battery sealing device according to any one of claims 1-9, characterized in that, The shell is a nickel-plated steel shell.

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