Single battery and high-capacity battery

Abstract

The invention discloses a single battery and a high-capacity battery. The single battery comprises a shell, an electrode assembly and a sealing unpacking piece, a one-way breathable film is arranged on the shell; the electrode assembly is positioned in the shell and is connected with a polar terminal at the top of the shell; a mounting part for mounting a heat exchange tube is arranged on the polar terminal; a sealed unpacking piece is arranged on the shell, and the sealed unpacking piece comprises an electrolyte additive which can be dissolved in the electrolyte and is made into a dissolving structure. The single battery provided by the invention is provided with the one-way gas-permeable membrane and the electrolyte additive to prepare a dissolving structure, so that secondary opening of the single battery during assembly of a high-capacity battery is avoided, and the assembly efficiency of the high-capacity battery is improved.

Description

Technical Field

[0001] The invention belongs to the field of batteries, and in particular relates to a single cell and a large-capacity battery. Background Art

[0002] Common lithium-ion batteries are divided into button batteries, square batteries and cylindrical batteries according to their appearance.

[0003] The electrode components in the square battery are arranged in the order of positive electrode-diaphragm-negative electrode, assembled by lamination or winding process, and then encapsulated in a square aluminum shell.

[0004] With the continuous development of science and technology, the market demand for batteries with high safety and large capacity is getting stronger and stronger. Therefore, how to ensure the safety of batteries while increasing the battery capacity has become a technical hotspot in the battery field.

[0005] A large-capacity battery is provided in the related technology. The large-capacity battery includes a plurality of single cells. Each single cell has a gas zone connected to its inner cavity through a gas chamber. After the gas zones are connected, the internal pressure of each single cell can be kept basically consistent, thereby reducing the problem of excessive internal pressure of a single cell causing the single cell to swell and fail, or even produce thermal runaway.

[0006] During the manufacturing process of the large-capacity battery, an opening is first made on the battery shell of each single cell, and then a sealing mechanism is installed on the primary opening. The main function of the sealing mechanism is to seal the single cell to protect the electrolyte in the single cell from contact with the air. When the single cells are assembled to form a large-capacity battery, the sealing mechanism needs to be detached from the single cell. At this time, a secondary opening is formed on the shell of the single cell. Finally, the inner cavity of each single cell is connected through the secondary opening. The above unpacking method requires unpacking the single cell twice, which makes the manufacturing process of the large-capacity battery cumbersome and the assembly efficiency is low. Summary of the invention

[0007] In order to solve the problem that in the existing large-capacity battery assembly process, single cells need to be unpacked twice, making the large-capacity battery manufacturing process cumbersome and the assembly efficiency low, the first aspect of the present invention provides a single cell.

[0008] The single cell battery comprises a shell, an electrode assembly and a sealed opening piece;

[0009] A one-way breathable membrane is provided on the shell;

[0010] The electrode assembly is located in the shell and connected to the polarity terminal on the top of the shell; the polarity terminal is provided with a mounting portion for mounting the heat exchange tube;

[0011] A sealed package opening piece is arranged on the shell, and the sealed package opening piece includes an electrolyte additive soluble in the electrolyte to form a dissolving structure.

[0012] A one-way breathable membrane is arranged on the single cell of the present invention, and the one-way breathable membrane can discharge the gas generated in the single cell out of the single cell shell. When the single cell is used to assemble a large-capacity battery, the gas pressure in the gas area of ​​each single cell can be kept basically consistent. Compared with the solution in the related art that achieves the same gas pressure in the gas area of ​​each single cell by secondary unpacking of the single cell, the manufacturing process is saved and the assembly efficiency is improved.

[0013] In addition, since the one-way breathable membrane is installed on the shell during the shell manufacturing process of the single cell, when the single cell is subjected to a formation treatment during the manufacturing process, the one-way breathable membrane can directly discharge the gas generated during the formation to the outside of the shell. Compared with the existing single cell, it saves the steps of opening and sealing the single cell when performing the formation treatment, thereby improving the manufacturing efficiency of the single cell.

[0014] Thirdly, the polarity terminals of the single cells of the present invention are provided with mounting parts for heat exchange tubes. When a plurality of single cells are assembled into a large-capacity battery, the temperature of the electrode assembly in each single cell can be transferred from the polarity terminals to an external temperature control device through the heat exchange tubes, thereby reducing the problem that overheating of the electrode assembly will affect the performance of the large-capacity battery. More importantly, direct temperature control of each electrode assembly reduces the probability of thermal runaway, thereby improving safety.

[0015] Fourth, a sealing opening piece that can be dissolved in the electrolyte is installed on the outer shell of the single cell. When the electrolyte is injected into the large-capacity battery during the process of assembling a large-capacity battery with a shared electrolyte system, the sealing opening piece is dissolved, and a through hole is formed on the single cell, thereby realizing the interconnection of the electrolyte areas in each single cell in the large-capacity battery. This process does not require special tooling, is simple to operate, and reduces the production cost. At the same time, since the sealing mechanism is solidified with an electrolyte additive, it can improve the performance of the large-capacity battery to a certain extent after being dissolved in the electrolyte.

[0016] Furthermore, a convex ring is provided on the shell, and the dissolving structure is installed in the convex ring; the dissolving structure includes a columnar body formed by an additive soluble in the electrolyte and an isolation membrane; at least the first end face of the columnar body has an isolation membrane, which is insoluble in the electrolyte.

[0017] Furthermore, the columnar body is made of propylene sulfate, ethylene carbonate or diphenyl carbonate.

[0018] Furthermore, in order to enable the sealing mechanism to slowly dissolve in the electrolyte and thus continuously improve the electrolyte performance, the first end face, the second end face and the side face of the column are coated with an isolation film, and a blind hole is provided in the column from the second end face to the first end face.

[0019] Furthermore, in order to achieve both fast opening speed and slow decomposition of the sealing mechanism in the electrolyte, the depth of the blind hole accounts for 90% of the length of the columnar body.

[0020] Furthermore, in order to enhance the sealing reliability of the sealing mechanism for the single battery, a sealing ring is provided between the columnar body and the convex ring.

[0021] Based on the above single battery, the second aspect of the present invention also provides two large-capacity batteries:

[0022] The first large-capacity battery comprises a first hollow tube, a second hollow tube and a plurality of the above-mentioned single cells;

[0023] Multiple single cells are placed side by side, and the positive terminals of all the single cells are connected as a total positive electrode, and the negative terminals of all the single cells are connected as a total negative electrode;

[0024] The first hollow tube is provided with a plurality of first through holes, the first hollow tube is connected to the shells of the individual cells, and the plurality of first through holes of the first hollow tube correspond to the one-way air-permeable membranes of the individual cells one by one, and the gas generated in each individual cell overflows into the first hollow tube through the one-way air-permeable membrane, so that the gas pressure in each individual cell remains consistent;

[0025] The second hollow tube is provided with a plurality of second through holes, the second hollow tube is connected to the shell of each single cell, and the second hollow tube is communicated with the electrolyte area in each single cell, so that the electrolyte areas of each single cell are communicated.

[0026] Furthermore, the above-mentioned large-capacity battery also includes a heat exchange tube; the heat exchange tube cooperates with the mounting portion of the polarity terminal of each single battery.

[0027] A second large-capacity battery comprises a box and a plurality of single cells as described in the first aspect;

[0028] Multiple single cells are arranged in the box along the same direction, and the electrolyte areas of each single cell are interconnected;

[0029] The top plate of the box body is provided with avoidance holes corresponding to the polarity terminals of each single battery; the polarity terminals of each single battery extend out of the avoidance holes, and the top plate area of ​​the outer shell corresponding to the avoidance holes is fixedly sealed with the shell of the single battery;

[0030] The positive terminals of all the single cells are connected as the total positive electrode, and the negative terminals of all the single cells are connected as the total negative electrode;

[0031] The box body is provided with a gas chamber extending along the arrangement direction of the single cells, and the gas chamber covers the one-way air permeable membrane of each single cell. The gas generated in each single cell overflows into the gas chamber through the one-way air permeable membrane, so that the air pressure in each single cell remains consistent.

[0032] Furthermore, the above-mentioned large-capacity battery also includes an electrolyte sharing chamber arranged on the box body and extending along the arrangement direction of the single cells; the electrolyte sharing chamber is connected to the electrolyte area of ​​each single cell.

[0033] Furthermore, the above-mentioned large-capacity battery also includes a heat exchange tube; the heat exchange tube cooperates with the mounting portion of the polarity terminal of each single battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0034] Figure 1 Schematic diagram of the single cell structure in Example 1 Figure 1 ;

[0035] Figure 2 Schematic diagram of the single cell structure in Example 1 Figure 2 ;

[0036] Figure 3 is a cross-sectional view of a single cell in Example 1;

[0037] Figure 4 It is a cross-sectional view of the sealed opened package;

[0038] Figure 5 This is a schematic diagram of the structure of a large-capacity battery in Example 2;

[0039] Figure 6 This is a schematic diagram of the large-capacity battery structure in Example 3.

[0040] The reference numerals are as follows:

[0041] 1-shell, 11-top cover, 12-housing, 13-bottom cover, 2-one-way breathable membrane, 3-polarity terminal, 4-mounting portion, 5-sealed opening piece, 6-convex ring, 7-column, 71-first end face, 72-second end face, 73-blind hole, 74-first cylindrical section, 75-second cylindrical section, 8-sealing ring;

[0042] 100 - single cell, 200 - first hollow tube, 300 - second hollow tube, 400 - housing, 500 - gas chamber, 600 - electrolyte shared chamber, 700 - heat exchange tube. DETAILED DESCRIPTION

[0043] The following will be combined with the accompanying drawings to clearly and completely describe the technical solutions in the embodiments. Obviously, the described embodiments are only part of the embodiments, not all of the embodiments. Based on the following embodiments, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0044] At the same time, it should be noted that the orientations or positional relationships indicated by the terms "top, bottom, inside and outside" in the text are based on the orientations or positional relationships shown in the drawings, and are only for the convenience of simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as limiting the technical solution. In addition, the terms "first, second or third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0045] In the present invention, unless otherwise clearly specified and limited, the terms "install, connect, connect" should be understood in a broad sense, for example: it can be a fixed connection, a detachable connection or an integral connection; it can also be a mechanical connection, an electrical connection or a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0046] The basic concept of the present invention is to provide a one-way breathable membrane on the shell of a single cell, so that when the single cell is used to form a large-capacity battery, there is no need to unpack the single cell, thereby saving the production process of the large-capacity battery and improving the assembly efficiency of the large-capacity battery.

[0047] Example 1

[0048] like Figure 1 and Figure 2 As shown, in this embodiment, the single cell 100 includes a housing 1, an electrode assembly and a sealed opening piece;

[0049] The housing 1 is provided with a one-way air-permeable membrane 2, which is used to discharge the gas generated in the single cell out of the housing; the electrode assembly is located in the housing and connected to the polarity terminal 3 on the top of the housing 1, and the electrolyte is located in the housing; the polarity terminal 3 is provided with a mounting portion 4 for mounting a heat exchange tube;

[0050] The housing 1 is a component for forming an internal environment of the single cell 100, wherein the formed internal environment can be used to accommodate the electrode assembly, electrolyte and other components. The housing 1 can be of various shapes and sizes, such as a rectangular parallelepiped. Specifically, the shape of the housing 1 can be determined according to the specific shape and size of the electrode assembly.

[0051] The shell 1 can be in the following two forms:

[0052] 1. The housing 1 includes a top cover 11 and an outer shell 12 with an open top. The top cover 11 is provided with positive and negative terminals of the single battery. The top cover 11 is sealed and mounted on the outer shell 12 with an open top.

[0053] 2. The housing 1 includes a top cover 11, a bottom cover 13 and an outer shell 12 with both top and bottom openings; the top cover 11 is provided with positive and negative terminals of the single battery; the top cover 11 is sealed and mounted on the top opening of the outer shell 12, and the bottom cover 13 is sealed and mounted on the bottom opening of the outer shell 12.

[0054] The electrode assembly is the part where the electrochemical reaction occurs in the single cell. The housing may contain one or more electrode assemblies. The electrode assembly is also provided with tabs. During the charge and discharge process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte. The electrode assembly is made of multiple layers of pole sheets by winding or laminating, and each layer of pole sheets includes a positive electrode sheet, a diaphragm and a negative electrode sheet.

[0055] A one-way air permeable membrane 2 is provided on the shell 1, and the one-way air permeable membrane 2 is used to discharge the gas generated in the single cell out of the shell; when the single cell 100 is used to assemble a large-capacity battery in which the gas areas of each single cell 100 are connected, there is no need to unpack the single cell a second time, which saves the production process and improves the assembly efficiency.

[0056] Specifically, the one-way air permeable membrane 2 can be arranged on the top or side wall of the housing 1, and its location needs to correspond to the gas area of ​​the inner cavity of the single battery 100, and this location needs to ensure that the gas in the single battery can be discharged out of the housing. In this embodiment, the one-way air permeable membrane is arranged on the top cover of the housing.

[0057] The one-way air permeable membrane 2 can be installed on the single battery 100 in the following two ways:

[0058] 1. It can be fixed on the shell 1 of the single battery 100 by injection molding during the manufacturing process of the single battery 100, that is, the single battery 100 is a homemade battery, and no explosion relief mechanism is required on the single battery 100; 2. It can also be modified by using a finished single battery, that is, first opening an opening on the shell of the single battery, and then fixing the one-way air permeable membrane 2 on the opening of the shell of the single battery 100 (the explosion relief membrane of the finished single battery can be removed to form an opening, and then the one-way air permeable membrane is used to seal the opening).

[0059] Compared with the second method, since the one-way breathable membrane 2 is installed in the shell during the shell manufacturing process of the single cell 100, when the single cell is subjected to a formation treatment, the one-way breathable membrane 2 can directly discharge the gas generated during the formation to the outside of the shell 1. Compared with the existing single cell, it saves the steps of opening and sealing the single cell when performing the formation treatment, thereby improving the manufacturing efficiency of the single cell.

[0060] The electrode assembly is located inside the shell and connected to the polarity terminal 3 on the top of the shell 1; a mounting portion 4 for mounting a heat exchange tube is provided on the polarity terminal 3; when a plurality of single cells 100 are assembled into a large-capacity battery, the temperature of the electrode assembly in each single cell 100 can be transferred from the polarity terminal to an external temperature control device through the heat exchange tube, thereby reducing the problem of overheating of the electrode assembly affecting the performance of the large-capacity battery. More importantly, direct temperature control of each electrode assembly reduces the probability of thermal runaway, thereby improving safety.

[0061] Specifically, the installation portion of the heat exchange tube in the present invention has two forms:

[0062] Method 1: A through hole is opened on the polarity terminal 3, and the through hole is arranged perpendicular to the axial direction of the polarity terminal 3; the aperture size of the through hole needs to ensure that the heat exchange tube is tightly clamped therein to ensure installation stability while ensuring the heat transfer effect between the heat exchange tube and the polarity terminal.

[0063] Method 2: A groove is provided on the top or side wall of the polarity terminal 3; the width of the groove needs to ensure that the heat exchange tube is tightly clamped therein, so as to ensure the installation stability while ensuring the heat transfer effect between the heat exchange tube and the pole.

[0064] Since the polarity terminal 3 of the single cell is charged, in order to ensure safety, the heat exchange tube and the polarity terminal 3 of the single cell must be insulated. The insulation can be maintained by oxidizing the heat exchange tube or providing an insulating layer in the area where the heat exchange tube contacts the polarity terminal.

[0065] The shell is provided with a sealing opening piece 5, which is a dissolving structure formed by an additive that can be dissolved in the electrolyte. The dissolving structure can be a sheet-like structure, which is fixed to the shell by injection molding; in this embodiment, a convex ring 6 is provided on the shell 1, and the dissolving structure is installed in the convex ring 6; the dissolving structure includes a columnar body 7 formed by an additive that can be dissolved in the electrolyte and an isolation membrane; at least the first end face of the columnar body 7 has an isolation membrane, which is insoluble in the electrolyte. Among them, the first end face 71 is the surface close to the inner cavity of the single cell, and the reason for providing the isolation membrane is to prevent the electrolyte in the single cell from dissolving the columnar body before the single cell is opened.

[0066] There are several ways to fix the sealing opening piece 5 to the convex ring:

[0067] 1. Apply adhesive to the outer wall of the sealed package opening member 5 or the inner wall of the convex ring 6, and seal and fix them by bonding;

[0068] 2. The sealing opening piece 5 is directly fixed in the convex ring 6 by means of interference fit;

[0069] 3. The sealing opening piece 5 is fixed in the convex ring 6 by means of interference fit with the sealing ring 8.

[0070] Since method 3 is easy to operate and has stronger sealing reliability, method 3 is preferred in this embodiment.

[0071] Preferably, in order to ensure the flatness of the appearance of the single battery, the protruding direction of the convex ring 6 in this embodiment is toward the inner cavity of the battery.

[0072] Specifically, the columnar body 7 is made of propylene sulfate, ethylene carbonate or diphenyl carbonate as an electrolyte additive, and the manufacturing process is as follows:

[0073] First, propylene sulfate crystals, ethylene carbonate crystals, or diphenyl carbonate crystals are ground into powder;

[0074] Then, the powder is heated to convert it into a liquid additive;

[0075] Then pour the liquid additive into the prepared mold, and form a column after natural cooling;

[0076] Finally, take out the column.

[0077] Among them, propylene sulfate, as an electrolyte additive, can improve the low-temperature performance of the electrolyte and prevent PC molecules from being embedded in the graphite electrode;

[0078] As an electrolyte additive, ethylene carbonate has the following functions:

[0079] 1. Transferring ions in battery reactions: In a battery, when the positive electrode and the negative electrode react, ions need to move in the battery to complete the reaction. Ethylene carbonate acts as an electrolyte to transfer ions and promote the reaction.

[0080] 2. Maintain charge balance: In the battery reaction, the positive and negative electrodes will consume or release charge. The charge needs to be balanced, otherwise it will affect the battery performance and life. Ethylene carbonate can maintain the charge balance in the battery by transferring ions, ensuring the normal operation of the battery.

[0081] 3. Improve battery performance: improve battery conductivity, enhance battery stability and safety.

[0082] As an electrolyte additive, diphenyl carbonate has good redox stability and thermal stability, can provide high conductivity and extend battery life.

[0083] Therefore, in actual use, any one of the above three substances can be selected as the material to make the column according to the needs, and then the performance of the battery can be improved and enhanced from different aspects.

[0084] 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. For safety and reliability considerations, the isolation film in this embodiment is preferably a PP film. When making the sealing mechanism, the isolation film can be coated on the column by heat sealing, coating or gluing.

[0085] Preferably, if Figure 3 and Figure 4 As shown, since the electrolyte additive is used as the sealed opening piece 5 in this embodiment, in order to enable the sealed opening piece 5 to slowly dissolve in the electrolyte, thereby continuously improving the electrolyte performance, the first end face 71, the second end face 72 and the side of the column 7 are coated with an isolation film (the second end face 72 is the surface away from the inner cavity of the single battery), and the column is provided with a blind hole 73 from the second end face 72 to the first end face 71. 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 column is covered by the isolation film, the electrolyte is always only in contact with the hole wall, and the electrolyte continues to slowly dissolve the column.

[0086] Preferably, in order to achieve both fast opening speed and slow decomposition of the sealed opening piece in the electrolyte, the depth of the blind hole 73 in this embodiment accounts for 90% of the length of the columnar body 7. That is to say, the bottom of the blind hole 73 is relatively thin, and the bottom of the blind hole will penetrate in a very short time, thereby realizing the opening of the single battery.

[0087] Preferably, if Figure 4 As shown, in order to facilitate the installation of the dissolving structure and the single battery housing, the columnar body 7 includes a first cylindrical section 74 and a second cylindrical section 75, and the outer diameter of the first cylindrical section 74 is larger than that of the second cylindrical section 75. The sealing ring 8 is arranged between the second cylindrical section 75 and the convex ring 6. In order to facilitate the installation of the sealing ring, a groove for placing the sealing ring is provided on the side wall of the columnar body of this embodiment.

[0088] Example 2

[0089] Based on the structure of the single cell in Example 1, this embodiment discloses a large-capacity battery, such as Figure 5As shown, it includes a first hollow tube 200, a second hollow tube 300 and a plurality of single cells 100; the plurality of single cells 100 are placed side by side, and the positive terminals of all the single cells 100 are connected as a total positive electrode, and the negative terminals of all the single cells 100 are connected as a total negative electrode;

[0090] The first hollow tube 200 is provided with a plurality of first through holes, and the first hollow tube 200 is fixed on the shell of each single cell 100, and the plurality of first through holes of the first hollow tube 200 correspond one by one to the one-way air-permeable membrane of the single cell. The gas generated in each single cell 100 overflows into the first hollow tube 200 through the one-way air-permeable membrane, so that the air pressure in each single cell remains consistent.

[0091] The second hollow tube 300 is provided with a plurality of second through holes, and the second hollow tube 300 is fixed on the shell of each single battery, and the plurality of second through holes of the second hollow tube 300 correspond one by one to the sealing opening piece 5 on the shell of the single battery, and when the sealing opening piece is dissolved, the electrolyte areas of each single battery are connected.

[0092] The first hollow tube 200 is in the form of a tube with a rectangular cross section, and the second hollow tube 300 is substantially the same in form as the first hollow tube 200. In this embodiment, the one-way air-permeable membrane is disposed on the top of the single battery housing, the first hollow tube 200 is located above the large-capacity battery, the sealing opening component is disposed at the bottom of the single battery housing, and the second hollow tube 300 is located below the large-capacity battery. The second hollow tube 300 can be used to connect with the liquid injection equipment and the explosion relief mechanism.

[0093] Example 3

[0094] Based on the structure of the single cell in Example 1, this embodiment discloses a large-capacity battery, such as Figure 6 As shown, it includes a box body 400 and a plurality of single batteries 100;

[0095] A plurality of single cells 100 are arranged in the box 400 along the same direction, and the electrolyte areas of the single cells are interconnected;

[0096] A pole avoidance hole is provided on the top plate of the box body 400 corresponding to the polarity terminal of each single battery; the polarity terminal of each single battery extends out of the pole avoidance hole, and the top plate area of ​​the box body corresponding to the pole avoidance hole is fixedly sealed with the single battery shell;

[0097] The positive terminals of all the single cells are connected as the total positive electrode, and the negative terminals of all the single cells are connected as the total negative electrode;

[0098] The box body 400 is provided with a gas chamber 500 extending along the arrangement direction of the single cells, and the gas chamber 500 covers the one-way air permeable membrane of each single cell. The gas generated in each single cell overflows into the gas chamber through the one-way air permeable membrane, so that the air pressure in each single cell remains consistent.

[0099] In order to ensure that the electrolyte areas of each single cell are connected and the continuity of the liquid level is good (to avoid liquid interruption), and at the same time ensure that there is a sufficient amount of electrolyte in the large-capacity battery, the large-capacity battery of this embodiment also includes an electrolyte sharing chamber 600 arranged on the box body 400 and extending along the arrangement direction of the single cells; the electrolyte sharing chamber 600 is connected to the electrolyte areas of each single cell.

[0100] The box has the following three forms:

[0101] 1. The box body 400 includes a cylinder, a first cover plate, and a second cover plate; the top and bottom of the cylinder are both open, the first cover plate is sealed and fixed (welded) to the top of the cylinder, and the second cover plate is sealed and fixed (welded) to the bottom of the cylinder;

[0102] The first cover plate is provided with a pole avoidance hole for the extension of the polarity terminals of multiple single cells, and the first cover plate is integrally formed with a groove body protruding upward, which serves as a gas chamber; the second cover plate is integrally formed with a groove serving as an electrolyte shared chamber.

[0103] 2. The box body 400 includes a U-shaped shell, a first cover plate, a third cover plate and a fourth cover plate; the top, front and rear of the U-shaped shell are all open, the first cover plate is sealed and fixed (welded) to the top of the U-shaped shell, and the third cover plate and the fourth cover plate are sealed and fixed (welded) to the front and rear of the U-shaped shell respectively.

[0104] The first cover plate is provided with 2N pole avoidance holes for the extension of the polarity terminals of multiple single cells. The first cover plate is integrally formed with an upwardly protruding groove body, which serves as a gas chamber; a groove is integrally formed on the bottom of the U-shaped shell as an electrolyte shared chamber.

[0105] 3. The box body 400 includes a cylinder, a third cover plate, and a fourth cover plate; the front and rear of the cylinder are open, the third cover plate is sealed and fixed (welded) to the front of the cylinder, and the fourth cover plate is sealed and fixed (welded) to the rear of the cylinder;

[0106] The top of the cylinder is provided with a plurality of pole avoidance holes for the extension of the polarity terminals of a plurality of single cells. The top of the cylinder is integrally formed with a groove body protruding upward, which serves as a gas chamber; the bottom of the cylinder is integrally formed with a groove serving as an electrolyte shared chamber.

[0107] In the above three types of shells, the cylinder and the U-shaped shell can be spliced ​​by welding, or can be integrally formed by casting or stamping. In order to facilitate processing and ensure sealing, the integral forming method is usually selected.

[0108] In order to ensure the sealing of the box, the box area corresponding to the pole avoidance hole needs to be fixedly sealed with the single battery shell; the fixed sealing at this location can be achieved in the following three ways:

[0109] Method 1: The edge of the pole avoidance hole can be welded to the top cover of the single battery to achieve sealing;

[0110] However, if the height dimensions of each single battery are not completely equal, some single battery covers with smaller height dimensions may have problems with poor welding or even be unable to be welded to the top of the box body. In this case, the following method 2 or method 3 can be used.

[0111] Method 2: A weak portion is provided in the peripheral area of ​​the pole avoidance hole. During the welding process, the size difference in the height direction of the top of each single battery shell is compensated by the deformation of the weak portion, so that the polarity terminals of all single batteries extend out of the pole avoidance hole. The weak portion in this embodiment can be an annular groove with the center of the pole avoidance hole as the center point and opened along the peripheral area of ​​the pole avoidance hole. In other embodiments, the weak portion can also be a long strip groove opened in the peripheral area of ​​the pole avoidance hole. In other embodiments, if there is a similar problem, that is, all the polarity terminals of the single batteries cannot be fully extended out of the pole avoidance hole at the same time, the solution can be adopted to add a weak portion in the peripheral area of ​​the pole avoidance hole.

[0112] Method 3: Add a hollow connector between the pole avoidance hole and the polarity terminal; the bottom of the hollow connector is used to be sealed and connected to the first area of ​​the single cell, and the top of the hollow connector is sealed and connected to the second area of ​​the box; the first area is the area located around any polarity terminal in any single cell; the second area is the area corresponding to any pole avoidance hole on the box. The area corresponding to the pole avoidance hole is the surrounding area on the outer surface of the top of the box corresponding to any pole avoidance hole; or the area corresponding to the pole avoidance hole is the wall of the pole avoidance hole. Among them, the area around the pole avoidance hole is the area around the insulating sealing pad on the pole avoidance hole. The insulating sealing pad is a part on the single cell used to insulate the pole avoidance hole and the top cover.

[0113] In the above embodiments 2 and 3, a heat exchange tube 700 is provided on the large-capacity battery; the heat exchange tube 700 cooperates with the mounting portion of the polarity terminal of each single battery.

[0114] The heat exchange tubes can be specifically arranged in the following ways:

[0115] 1. An aluminum tube is bent into a U-shaped structure, and two parallel tube sections are used to cooperate with the total positive electrode and the total negative electrode respectively, so as to realize the heat exchange between each single battery and the external temperature control device, and the liquid inlet and liquid outlet of the aluminum tube are located on the same side; the transmission medium in the aluminum tube can be water, insulating oil or fluorinated liquid; or two aluminum tubes can be used to cooperate with the total positive electrode and the total negative electrode respectively.

[0116] 2. Two cored heat pipes are used to cooperate with the total positive electrode and the total negative electrode respectively, so as to realize the heat exchange between each single battery and the external temperature control device. The cored heat pipe is an evaporation-condensation type heat exchange equipment, which realizes heat transmission by the state change of the working fluid in the pipe.

[0117] Since the heat transfer effect of the cored heat pipe is affected by the length of the cored heat pipe, when the number of single cells in a large-capacity battery is large (i.e., the length of the large-capacity battery is long), the use of the cored heat pipe will be limited. Therefore, in this embodiment, aluminum tubes are preferably selected as heat exchange tubes. If the insulation between the heat exchange tubes and the polarity terminals can be effectively ensured, water can be preferably used as the heat transfer medium flowing in the aluminum tube from the aspects of heat transfer efficiency and cost.

Claims

1. A single cell battery, characterized in that: It includes a shell, an electrode assembly and a sealed opening piece; A one-way breathable membrane is arranged on the shell; the electrode assembly is located inside the shell and connected to the polarity terminal on the top of the shell; a mounting portion for mounting a heat exchange tube is arranged on the polarity terminal; a sealed opening piece is arranged on the shell, and the sealed opening piece includes a dissolving structure formed by an electrolyte additive soluble in the electrolyte.

2. The single cell according to claim 1, characterized in that: A convex ring is arranged on the shell, and the dissolving structure is installed in the convex ring; the dissolving structure comprises a columnar body formed by an additive soluble in the electrolyte and an isolation membrane; at least the first end face of the columnar body has an isolation membrane, which is insoluble in the electrolyte.

3. The single cell according to claim 2, characterized in that: The columnar body is made of propylene sulfate, ethylene carbonate or diphenyl carbonate.

4. The single cell according to claim 3, characterized in that: The first end surface, the second end surface and the side surface of the columnar body are covered with an isolation film, and a blind hole is arranged on the columnar body from the second end surface to the first end surface.

5. The single cell according to claim 4, characterized in that: The hole depth of the blind hole accounts for 90% of the length of the columnar body.

6. The single cell according to claim 5, characterized in that: A sealing ring is arranged between the columnar body and the convex ring.

7. A large capacity battery, characterized in that: comprising a first hollow tube, a second hollow tube and a plurality of single cells as claimed in claim 1; Multiple single cells are placed side by side, and the positive terminals of all the single cells are connected as a total positive electrode, and the negative terminals of all the single cells are connected as a total negative electrode; The first hollow tube is provided with a plurality of first through holes, the first hollow tube is connected to the shells of the individual cells, and the plurality of first through holes of the first hollow tube correspond to the one-way air-permeable membranes of the individual cells one by one, and the gas generated in each individual cell overflows into the first hollow tube through the one-way air-permeable membrane, so that the gas pressure in each individual cell remains consistent; The second hollow tube is provided with a plurality of second through holes, the second hollow tube is connected to the shell of each single cell, and the second hollow tube is communicated with the electrolyte area in each single cell, so that the electrolyte areas of each single cell are communicated.

8. A large capacity battery, characterized in that: comprising a box body and a plurality of single cells as claimed in claim 1; Multiple single cells are arranged in the box along the same direction, and the electrolyte areas of each single cell are interconnected; The top plate of the box body is provided with avoidance holes corresponding to the polarity terminals of each single battery; the polarity terminals of each single battery extend out of the avoidance holes, and the top plate area of ​​the outer shell corresponding to the avoidance holes is fixedly sealed with the shell of the single battery; The positive terminals of all the single cells are connected as the total positive electrode, and the negative terminals of all the single cells are connected as the total negative electrode; The box body is provided with a gas chamber extending along the arrangement direction of the single cells, and the gas chamber covers the one-way air permeable membrane of each single cell. The gas generated in each single cell overflows into the gas chamber through the one-way air permeable membrane, so that the air pressure in each single cell remains consistent.

9. A large capacity battery according to claim 8, characterized in that: It also includes an electrolyte sharing chamber which is arranged on the box body and extends along the arrangement direction of the single cells; the electrolyte sharing chamber is connected to the electrolyte area of ​​each single cell.

10. A large capacity battery according to claim 8, characterized in that: It also includes a heat exchange tube; the heat exchange tube is matched with the mounting portion of the polarity terminal of each single battery.

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