A sealing mechanism and a single battery

Abstract

The application discloses a sealing mechanism and a single battery. The sealing mechanism comprises a columnar body formed by an additive soluble in electrolyte; at least a first end surface of the columnar body is provided with a separation film which is insoluble in electrolyte. The sealing mechanism is installed on a single battery shell. When the electrolyte is injected, the sealing mechanism is dissolved, a through hole is formed on the single battery, and the single battery is unpacked. The process does not need special tooling, is simple to operate, and reduces manufacturing cost. Meanwhile, the sealing mechanism is solidified by electrolyte additives, and the performance of a large-capacity battery is improved after the sealing mechanism is dissolved in the electrolyte.

Description

TECHNICAL FIELD

[0001] The application belongs to the field of batteries, in particular to a sealing mechanism and a single battery. BACKGROUND

[0002] In order to meet the use scene of large capacity, the existing battery with large capacity is composed of multiple finished single batteries through parallel connection, series connection or series-parallel connection. The battery module connected in series can increase the total voltage, and the battery module connected in parallel can increase the total capacity.

[0003] However, no matter which way is used, the existing battery module has differences between each single battery itself, so that the consumption of electrolyte and lithium ions of each single battery is different after the battery module is operated for a period of time, the uniformity of each single battery is poor, and then the cycle life of the battery module is directly limited, so how to ensure the large capacity and improve the uniformity of each single battery in the battery module has become the focus and difficulty of the field.

[0004] The related technology provides a large-capacity battery, electrolyte regions of each single battery in the large-capacity battery are connected to each other, so that each single battery is in a unified shared electrolyte system, and therefore the consumption of electrolyte of each single battery is always consistent, the uniformity of each single battery is improved, and the cycle life of the large-capacity battery is improved to a certain extent.

[0005] The single battery of the large-capacity battery is provided with a sealing mechanism, the sealing mechanism needs to be opened when the shared electrolyte system is formed, and then a through hole for sharing electrolyte is formed on the single battery. The sealing mechanism recorded in the related technology needs to use a special tool when it is opened, which leads to complex operation and high manufacturing cost. SUMMARY

[0006] In order to avoid the problem that the single battery of the large-capacity battery in the related technology needs a special tool when it is unpacked, leading to complex operation and high manufacturing cost, the first aspect of the present application provides a sealing mechanism.

[0007] The sealing mechanism includes a columnar body formed by an additive that is soluble in electrolyte; at least a first end surface of the columnar body has a separation film, and the separation film is insoluble in electrolyte. The sealing mechanism is installed on the single battery shell. When the electrolyte is injected, the sealing mechanism is dissolved, a through hole is formed on the single battery, and the unpacking of the single battery is realized. This process does not need a special tool, the operation is simple, and the manufacturing cost is reduced. At the same time, since the sealing mechanism is solidified by electrolyte additives, the performance of the large-capacity battery can be improved to a certain extent after it is dissolved in the electrolyte.

[0008] Further, the columnar body is made of propylene sulfate or ethylene carbonate or diphenyl carbonate.

[0009] Further, in order to enable the sealing mechanism to slowly dissolve in the electrolyte, thereby enabling the performance of the electrolyte to be continuously improved, the first end face, the second end face and the side face of the columnar body are coated with a separation film, and the columnar body is provided with a blind hole from the second end face to the first end face.

[0010] Further, in order to enable the sealing mechanism to slowly dissolve in the electrolyte, thereby enabling the performance of the electrolyte to be continuously improved, the first end face, the second end face and the side face of the columnar body are coated with a separation film, and the columnar body is provided with a blind hole from the second end face to the first end face.

[0011] Further, in order to enhance the sealing reliability of the sealing mechanism to the single battery, a groove for mounting a sealing ring is engraved on the side wall of the columnar body.

[0012] Further, the columnar body comprises a first cylindrical segment and a second cylindrical segment, the outer diameter of the first cylindrical segment is greater than that of the second cylindrical segment, and the groove is arranged on the side face of the second cylindrical segment.

[0013] Further, the first end face, the second end face and the side face of the columnar body are coated with a separation film, and the second end face is provided with a blind hole.

[0014] Further, the separation film is a pp film.

[0015] The second aspect of the present application provides a single battery comprising a battery shell and a sealing mechanism provided by the first aspect described above; the battery shell has a convex ring, and the sealing mechanism is fixedly sealed in the convex ring.

[0016] Further, the protruding direction of the convex ring is towards the inner cavity of the battery.

[0017] Further, the pole column of the single battery is provided with a clamping part for clamping a heat transfer pipe. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 It is a structural schematic diagram of the first large-capacity battery;

[0019] Figure 2 It is a structural schematic diagram of the second large-capacity battery;

[0020] Figure 3 It is a sectional view of the sealing mechanism;

[0021] Figure 4 It is a structural schematic diagram of the single battery;

[0022] Figure 5 It is a sectional view of the single battery.

[0023] The reference signs are:

[0024] 100-Box body, 200-Single cell, 300-Hollow component, 400-Sealing mechanism, 1-Columnar body, 11-First cylindrical segment, 12-Second cylindrical segment, 2-First end face, 3-Second end face, 4-Blind hole, 5-Groove, 6-Protruding ring, 7-Sealing ring, 500-Heat transfer tube. Detailed Implementation

[0025] To make the above-mentioned objects, features, and advantages of the present invention more apparent and understandable, specific embodiments of the present invention will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of the present invention.

[0026] Many specific details are set forth in the following description in order to provide a full understanding of the invention. However, the invention may also be practiced in other ways different from those described herein, and those skilled in the art can make similar extensions without departing from the spirit of the invention. Therefore, the invention is not limited to the specific embodiments disclosed below.

[0027] In the description of this invention, it should be noted that the terms "top" and "upper" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limiting this invention.

[0028] The following two high-capacity battery structures are applicable in this embodiment:

[0029] First structure:

[0030] like Figure 1 As shown, the high-capacity battery includes a housing 100 and N individual cells 200; N ≥ 2; the N individual cells 200 are connected in parallel and arranged inside the housing 100; the inner cavity of each individual cell 200 includes an electrolyte area and a gas area, and the electrolyte areas of each individual cell 200 are interconnected, thus placing each individual cell in a single electrolyte system; the top of the housing 100 has a terminal clearance hole that allows the terminals of each individual cell 200 to extend; the terminals of each individual cell 200 extend out of the terminal clearance hole, and the housing area corresponding to the terminal clearance hole is fixedly sealed to the outer shell of the individual cell 200.

[0031] To ensure the continuity of electrolyte within each individual battery cell, an electrolyte channel is provided at the sealing mechanism location of each individual battery cell (this electrolyte channel is located at the bottom of the box). The electrolyte within each individual battery cell is connected through this electrolyte channel, resulting in better continuity of the electrolyte surface.

[0032] The second structure:

[0033] As shown in Figure 2 , the large-capacity battery comprises a hollow member 300 and N single batteries 200; N≥2; the N single batteries 200 are connected in parallel in sequence, the inner cavity of each single battery 200 comprises an electrolyte area and a gas area, and the electrolyte areas of the inner cavities of the single batteries 200 are connected to each other through the hollow member 300 (the hollow member is an electrolyte channel), thereby enabling the single batteries to be in one electrolyte system.

[0034] The hollow member 300 can be a complete circular or rectangular tube; the hollow member can also be formed by extrusion splicing of sub-pipes on the single batteries.

[0035] In the large-capacity battery in the above two forms, the electrolyte areas of the single batteries need to be connected to each other, and therefore the sealing mechanism 400 on the single battery needs to be opened, as shown in Figure 3 , the sealing mechanism 400 in the embodiment adopts a columnar body 1 formed by an electrolyte additive; the columnar body 1 has a separation film at least on the first end surface 2, and the separation film is insoluble in the electrolyte. The first end surface 2 is the surface close to the inner cavity of the single battery, and the separation film is provided for the following reason: to avoid that the electrolyte in the single battery dissolves the columnar body before the single battery is unpacked.

[0036] The sealing mechanism 400 is installed on the outer shell of the single battery 200, and after the electrolyte is injected into the electrolyte channel, the sealing mechanism 400 is dissolved, a through hole is formed on the single battery 200, and the single battery is unpacked, which does not require special tooling, is simple to operate, and reduces the manufacturing cost; at the same time, since the sealing mechanism is formed by an electrolyte additive, the performance of the large-capacity battery can be improved to a certain extent after the electrolyte additive is dissolved in the electrolyte.

[0037] Specifically, the columnar body is made of propylene sulfate or ethylene carbonate or diphenyl carbonate as an electrolyte additive, and the manufacturing process is as follows:

[0038] First, the propylene sulfate crystal or the ethylene carbonate crystal or the diphenyl carbonate crystal is ground into powder;

[0039] Then, the powder is heated to convert it into a liquid additive;

[0040] Then, the liquid additive is poured into a pre-prepared mold, and after natural cooling, the columnar body is formed;

[0041] Finally, the columnar body is taken out.

[0042] Among them, propylene sulfate as an electrolyte additive can improve the low-temperature performance of the electrolyte, and can also prevent PC molecules from being embedded in the graphite electrode;

[0043] Ethylene carbonate as an electrolyte additive, its role mainly has the following several aspects:

[0044] 1. In the battery reaction transfer ions: in the battery, when the positive and negative electrode reaction, ions need to move in the battery to complete the reaction, ethylene carbonate as electrolyte played a transfer ions, promote the reaction.

[0045] 2. Keep charge balance: in the battery reaction, the positive and negative electrode will consume or release charge. And charge is needed to keep balance, otherwise it will affect the battery performance and life. Ethylene carbonate can keep the charge balance in the battery by transferring ions, to ensure the normal work of the battery.

[0046] 3. Improve battery performance: improve the conductivity of the battery, enhance the stability and safety of the battery.

[0047] Diphenyl carbonate as an electrolyte additive has good redox stability and thermal stability, can provide high conductivity and prolong the life of the battery.

[0048] Therefore, in actual use, according to the needs, any one of the above three substances can be selected as the material to make the columnar body, and then the performance of the battery can be improved and enhanced from different aspects.

[0049] The isolation film only needs to meet the requirements of not reacting with the electrolyte and not dissolving in the electrolyte. There are many such film materials. In order to be safe and reliable, the isolation film in this embodiment is preferably pp film. When making the sealing mechanism, the isolation film can be coated on the columnar body by heat sealing, coating or gluing.

[0050] Preferably, as shown in Figure 3 Since the electrolyte additive is used as the sealing mechanism 400 in this embodiment, in order to make the sealing mechanism slowly dissolve in the electrolyte, so as to continuously improve the performance of the electrolyte, the first end surface 2, the second end surface 3 and the side surface of the above columnar body 1 are coated with an isolation film (the second end surface 3 is the surface away from the inner cavity of the single battery), and the columnar body is provided with a blind hole 4 from the second end surface 3 to the first end surface 2. When the electrolyte is injected into the electrolyte channel, the electrolyte can only contact the hole wall and the hole bottom of the blind hole due to the existence of the isolation film. First, the bottom of the blind hole is penetrated, and the single battery is opened. Since the rest of the columnar body is coated with an isolation film, the electrolyte is always in contact with the hole wall, and the electrolyte continuously and slowly dissolves the columnar body.

[0051] Preferably, in order to achieve both fast unpacking speed and slow decomposition of the sealing mechanism in electrolyte, the hole depth of the blind hole 4 in the embodiment accounts for 90% of the length of the columnar body 1. That is, the hole bottom of the blind hole is thin, and the hole bottom of the blind hole will be penetrated in a very short time, thereby achieving unpacking of the single battery.

[0052] Preferably, in order to enhance the sealing reliability of the sealing mechanism to the single battery, a groove 5 for installing a sealing ring is arranged on the side wall of the columnar body 1 in the embodiment. The groove can be arranged in the following ways:

[0053] 1. An annular protrusion is arranged on the inner wall of the mold, and after the liquid additive is poured into the mold and cooled, the groove is formed on the columnar body.

[0054] 2. After the columnar body is formed, the groove is formed on the columnar body by machining.

[0055] Preferably, as shown in Figure 3 , in order to facilitate the cooperation and installation of the sealing mechanism and the single battery shell, the columnar body 1 includes a first cylindrical segment 11 and a second cylindrical segment 12, the outer diameter of the first cylindrical segment 11 is greater than that of the second cylindrical segment 12, and the groove 5 is arranged on the side of the second cylindrical segment 12.

[0056] As shown in Figure 4 and Figure 5 , the embodiment provides a single battery 200, which includes a shell and a cell assembly; the cell assembly can also be referred to as an electrode assembly, which is assembled by arranging a positive electrode, a separator and a negative electrode in sequence and adopting a lamination or winding process; the shell includes an upper cover plate, a lower cover plate and a cylinder; in some cases, the lower cover plate and the cylinder can be integrally formed. The shell has a convex ring 6 (in the embodiment, the convex ring 6 is arranged at the bottom, i.e., on the lower cover plate), and a sealing mechanism 400 is fixedly sealed in the convex ring 6.

[0057] The sealing mechanism is fixedly sealed in the convex ring in the following ways:

[0058] 1. An adhesive is applied to the outer side wall of the sealing structure 400 or the inner wall of the convex ring 6, and the sealing structure 400 is fixedly sealed by adhesion;

[0059] 2. The sealing mechanism 400 is directly fixed in the convex ring 6 by interference fit;

[0060] 3. The sealing mechanism 400 is fixed in the convex ring 6 by interference fit combined with a sealing ring 7.

[0061] Since the third way is convenient to operate and has higher sealing reliability, the third way is preferred in the embodiment.

[0062] Preferably, in order to ensure the flatness of the monomer battery shape, the protruding direction of the convex ring 6 in the embodiment is towards the battery cavity.

[0063] Since the most concentrated part of heat in the monomer battery 200 is the pole, the pole of each monomer battery in the embodiment is provided with a heat pipe clamping portion; see Figure 1 and Figure 2 The heat pipe 500 is fixed on the heat pipe clamping portion of each monomer battery pole, and the heat pipe 500 and the heat pipe clamping portion of each monomer battery are insulated. Through the heat pipe, not only the balanced heat dissipation of each monomer battery is realized, the use safety of the large capacity battery is improved, but also the structure is simple, easy to manufacture and assemble, and the manufacturing cost is low. The heat pipe clamping portion can be a groove or a through hole provided on the polarity terminal.

[0064] In other embodiments, the sealing mechanism can also be provided in a sheet shape, and is fixed on the through hole of the monomer battery shell by bonding. If a sheet-shaped sealing mechanism is used, the sealing mechanism can be dissolved in a short time, so it can only improve the performance of the electrolyte in the initial stage of the operation of the large capacity battery, and the cycle life of the large capacity battery is not obviously improved.

Claims

1. A sealing mechanism, characterized by, The columnar body is made of propylene sulfate or ethylene carbonate or diphenyl carbonate and an additive which can be dissolved in electrolyte. The columnar body is made by the following steps: firstly, propylene sulfate or ethylene carbonate or diphenyl carbonate is ground into powder; secondly, the powder is heated to be liquid; thirdly, the liquid is poured into a prepared mold and cooled to form the columnar body; finally, the columnar body is taken out, and the first end surface, the second end surface and the side surface of the columnar body are covered with a separation film, and the columnar body is provided with a blind hole from the second end surface to the first end surface.

2. A sealing mechanism according to claim 1, wherein The depth of the blind hole accounts for 90% of the length of the columnar body.

3. A sealing mechanism according to claim 1 or 2, wherein A groove for mounting a sealing ring is engraved on the side wall of the columnar body.

4. A sealing mechanism according to claim 3, wherein The columnar body comprises a first cylindrical segment and a second cylindrical segment, the outer diameter of the first cylindrical segment is larger than that of the second cylindrical segment, and the groove is arranged on the side surface of the second cylindrical segment.

5. A sealing mechanism according to claim 4, wherein The separation film is a pp film.

6. A single cell characterized by The sealing mechanism is fixed and sealed in the convex ring on the battery shell.

7. The cell according to claim 6, wherein The protruding direction of the convex ring is towards the inner cavity of the battery.

8. The cell according to claim 7, wherein The pole of the single battery is provided with a clamping part for clamping a heat transfer pipe.

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