High-capacity battery

Abstract

The utility model discloses a high-capacity battery which comprises a box body, battery monomers and a fire-fighting medium storage bin, the plurality of single batteries are arranged in the box body side by side, and the inner cavity of each single battery is provided with an electrolyte region and a gas region; the electrolyte regions of the inner cavities of the battery monomers are communicated with one another; a partition plate is arranged between every two adjacent battery monomers, at least one partition plate is filled with a fire-fighting medium, at least one release hole is formed in each partition plate, and a sealing piece fixedly covers each release hole. According to the utility model, the electrolyte consumption of each battery monomer can be kept basically consistent all the time, so that the consistency of each battery monomer is ensured, and the cycle life of the high-capacity battery is prolonged; besides, the partition plate can restrain the battery monomers from expanding, meanwhile, when the temperature reaches the set temperature, the sealing piece on the partition plate is melted, the release hole is opened, the fire-fighting medium overflows into the inner cavity of the high-capacity battery box body, and thermal runaway is restrained due to the fact that the fire-fighting medium acts in the shared electrolyte system.

Description

Technical Field

[0001] The utility model belongs to the field of batteries, and in particular relates to 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. Summary of the invention

[0005] In order to solve the problem of how to ensure battery safety under the premise of increasing battery capacity, the utility model provides a large-capacity battery.

[0006] The large-capacity battery includes a box body, a battery cell and a fire-fighting medium storage bin;

[0007] There are N battery cells, N≥2; the N battery cells are arranged side by side in the box, and the inner cavity of the battery cells has an electrolyte area and a gas area; the electrolyte areas in the inner cavities of the battery cells are interconnected, so that the battery cells are in the same shared electrolyte system;

[0008] Avoidance holes are provided on the top plate of the box body corresponding to the polarity terminals of each battery cell; each battery cell polarity terminal extends out of the avoidance hole, and the top plate area of ​​the box body corresponding to the avoidance hole is fixedly sealed with the battery cell shell;

[0009] The positive terminals of all battery cells are connected as a total positive electrode, and the negative terminals of all battery cells are connected as a total negative electrode;

[0010] There are N-1 partitions, one partition is arranged between each adjacent battery cell, at least one partition is filled with fire-fighting medium, at least one release hole is arranged on the partition, and a seal is fixedly covered on the release hole. After the seal melts at a set temperature, the fire-fighting medium overflows from the release hole into the box.

[0011] In the utility model, since each battery cell is in a shared electrolyte system, the electrolyte consumption of each battery cell can always remain basically consistent, ensuring the consistency of each battery cell and improving the cycle life of the large-capacity battery; in addition, since a partition is provided between each battery cell of the large-capacity battery, the partition can suppress the expansion of the battery cell, thereby improving the performance of the large-capacity battery, and at the same time, at least one partition is filled with a fire-fighting medium. When the temperature reaches the set temperature, the seal on the partition is melted, the release hole is opened, and the fire-fighting medium overflows into the inner cavity of the large-capacity battery box. Since the fire-fighting medium acts on the shared electrolyte system, it can not only suppress the occurrence of thermal runaway, but also when a battery cell has thermal runaway, the fire-fighting medium can also suppress the spread of thermal runaway.

[0012] Furthermore, the top and bottom of the partition filled with fire-fighting medium are provided with seals, so that release holes can be formed at the top and bottom of the fire-fighting medium storage bin, so that the fire-fighting medium in the fire-fighting medium storage bin can smoothly enter the inner cavity of the large-capacity battery box, thereby improving the fire-fighting effect.

[0013] Furthermore, since the lithium-ion battery is in the high-temperature triggering stage between 60°C and 100°C, the battery can still be in a safe operation stage at this stage, but thermal runaway is about to occur. Therefore, the above-mentioned seal is a polyethylene layer. When in use, the polyethylene layer is not only insoluble in the electrolyte, but also has a melting temperature of 85-136°C. After the polyethylene layer melts, the fire-fighting medium in the partition overflows.

[0014] Furthermore, the wall thickness of the partition is 1 to 1.5 mm.

[0015] Furthermore, in order to keep each battery cell in a substantially identical air pressure environment at all times and reduce the probability of thermal runaway of a large-capacity battery, a gas communication channel for connecting the gas zones of each battery cell is provided on the top of the box.

[0016] Furthermore, in order to ensure better continuity of the electrolyte level when the electrolyte areas of each battery cell are connected and avoid liquid interruption, and also to enable the firefighting medium in the firefighting medium storage bin to flow smoothly into the box, an electrolyte connecting channel is provided at the bottom of the box.

[0017] Furthermore, the large-capacity battery further comprises a heat exchange tube; the heat exchange tube cooperates with the mounting portion of each battery cell polarity terminal. The heat exchange tube is connected to each battery cell polarity terminal so as to conduct the heat of the polarity terminal with the most concentrated heat on each battery cell to the outside for heat dissipation. This heat dissipation method not only realizes balanced heat dissipation of each battery cell in the large-capacity battery and improves the safety of the large-capacity battery, but also has a simple structure, is easy to manufacture and assemble, and has a low manufacturing cost.

[0018] Furthermore, the fire-fighting medium is perfluorohexanone. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the utility model or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the utility model. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 This is a schematic diagram of the structure of a large-capacity battery in Example 1;

[0021] Figure 2 is a cross-sectional view of a large-capacity battery in Example 1;

[0022] Figure 3 is a schematic diagram of the structure of a battery cell in Example 1;

[0023] Figure 4 This is a schematic diagram of the structure of a large-capacity battery in Example 2;

[0024] Figure 5 is a cross-sectional view of a large-capacity battery in Example 2;

[0025] Figure 6 is a schematic diagram of the structure of a battery cell in Example 2;

[0026] The reference numerals are as follows:

[0027] 1-shell, 11-top cover, 12-shell, 13-bottom cover, 2-first sealed opening piece, 3-positive terminal, 4-negative terminal, 5-second sealed opening piece, 6-heat exchange tube installation part;

[0028] 100 - box body, 200 - battery cell, 300 - partition, 400 - gas communication channel, 500 - electrolyte communication channel, 600 - heat exchange tube, 700 - liquid injection and replacement interface. DETAILED DESCRIPTION

[0029] 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 this utility model.

[0030] 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.

[0031] In this utility model, unless otherwise 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 connection inside a machine. For ordinary technicians in this field, the specific meanings of the above terms in this utility model can be understood according to specific circumstances.

[0032] Example 1

[0033] like Figure 1 and Figure 2 As shown, this embodiment discloses a large-capacity battery, including a box body 100, a battery cell 200 and a separator 300;

[0034] There are multiple battery cells 200; the multiple battery cells 200 are arranged side by side in the box, and the inner cavity of the battery cell 200 has an electrolyte area and a gas area; the electrolyte areas in the inner cavities of the battery cells 200 are interconnected, so that the battery cells 200 are in a shared electrolyte system; because the battery cells are in a shared electrolyte system, the electrolyte consumption of each battery cell can always remain basically consistent, ensuring the consistency of each battery cell and improving the cycle life of the large-capacity battery;

[0035] Avoidance holes are provided on the top plate of the box body 100 corresponding to the polarity terminals of each battery cell 200; the polarity terminals of each battery cell 200 extend out of the avoidance holes, and the top plate area of ​​the box body 100 corresponding to the avoidance holes is fixedly sealed with the shell of the battery cell 200;

[0036] The positive terminals of all battery cells 200 are connected as a total positive electrode, and the negative terminals of all battery cells 200 are connected as a total negative electrode;

[0037] There are N-1 partitions 300, one partition 300 is arranged between each adjacent battery cell, at least one partition 300 is filled with a fire-fighting medium, at least one release hole is arranged on the partition 300 filled with the fire-fighting medium, and a seal is fixedly covered on the release hole. After the seal melts at a set temperature, the fire-fighting medium overflows from the release hole into the box body.

[0038] Since a partition 300 is arranged between each battery cell 200 of the large-capacity battery, the partition 300 can suppress the expansion of the battery cell 200, thereby improving the performance of the large-capacity battery. At the same time, at least one partition 300 is filled with a fire-fighting medium. When the temperature reaches the set temperature, the seal on the partition is melted, the release hole is opened, and the fire-fighting medium overflows into the inner cavity of the large-capacity battery case. Since the fire-fighting medium acts on the shared electrolyte system, it can not only suppress the occurrence of thermal runaway, but also suppress the spread of thermal runaway when thermal runaway occurs in a battery cell.

[0039] The box body 100 is also provided with a liquid injection and replacement interface 700 for injecting, replenishing, and replacing liquid in the large-capacity battery;

[0040] In this embodiment, the N-1 partitions 300 have two forms: one form of the partition 300 is a hollow structure filled with a fire-fighting medium, and the other form of the partition is a solid structure;

[0041] When setting, the N-1 partitions 300 may all be hollow structures filled with firefighting medium, or one of the partitions 300 may be a hollow structure filled with firefighting medium, and the remaining partitions may be solid structures;

[0042] The firefighting medium may be water, or a mixture of water and ethylene glycol, or perfluorohexanone; in terms of the cooling effect and the effect of inhibiting the spread of thermal runaway, in this embodiment, perfluorohexanone is preferably used as the firefighting medium.

[0043] The seal is made of a material that is insoluble in the electrolyte and begins to melt at about 100°C. There are two ways to set the seal:

[0044] First, the seal is integrally formed on the partition 300 by injection molding, and is a layer structure made of polyethylene material; when the seal melts, a release hole is formed on the partition;

[0045] The second method is that a release hole is opened on the partition 300, and a layer structure made of polyethylene material is used as a sealing member and fixedly covered on the release hole of the warehouse body by hot melting.

[0046] The battery cell of this embodiment is similar in structure to a square aluminum lithium-ion battery. Specifically, Figure 3 As shown, the battery cell 200 includes a housing 1, an electrode assembly, and a first sealing opening component 2;

[0047] The housing 1 is a component for forming an internal environment of the battery cell 200, 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.

[0048] The shell 1 can be in the following two forms:

[0049] 1. The housing 1 comprises a top cover 11 and an outer shell 12 with an open top; the top cover 11 is provided with a positive terminal 3 and a negative terminal 4 of the battery cell; the top cover 11 is sealed and mounted on the outer shell 12 with an open top, and a first sealing opening member 2 is provided at the bottom of the outer shell 12;

[0050] 2. The shell 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 a positive terminal 3 and a negative terminal 4 of the battery cell; the top cover 11 is sealed and installed on the top opening of the outer shell 12, the bottom cover 13 is sealed and installed on the bottom opening of the outer shell 12, and a first sealed opening component 2 is provided on the bottom cover 13.

[0051] The first sealing opening component 2 can be opened under external force to form a liquid hole on the battery cell shell. The first sealing opening component 2 can select the sealing mechanism disclosed in Chinese patent, publication number CN219457981 U, or select the sealing mechanism disclosed in Chinese patent, publication number CN117810623A.

[0052] The first sealing opening component 2 can be installed on the battery cell shell in advance during the battery cell manufacturing process, or the finished battery cell can be modified by first opening a liquid hole on the finished battery cell and then installing the first sealing opening component at the liquid hole.

[0053] The electrode assembly is the part of the battery cell where the electrochemical reaction occurs. 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 separator and a negative electrode sheet.

[0054] There are three types of boxes for large-capacity batteries:

[0055] 1. The box body 100 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;

[0056] The first cover plate is provided with a plurality of pole avoidance holes for the extension of the polarity terminals of a plurality of battery cells, and the second cover plate is integrally formed with a groove serving as an electrolyte communication channel 500 .

[0057] 2. The box body 100 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.

[0058] The first cover plate is provided with a plurality of pole avoidance holes for the extension of the polarity terminals of the plurality of battery cells, and a groove serving as an electrolyte communication channel 500 is integrally formed on the bottom of the U-shaped shell.

[0059] 3. The box body 100 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;

[0060] 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 battery cells, and the bottom of the cylinder is integrally formed with a groove serving as an electrolyte communication channel 500 .

[0061] In the above three types of boxes, 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.

[0062] 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 battery cell shell; the fixed sealing at this location can be achieved in the following three ways:

[0063] Method 1: The edge of the pole avoidance hole can be welded to the top cover of the battery cell to achieve sealing; however, if the dimensions of each battery cell along the height direction are not completely equal, some battery cells with smaller height dimensions may have problems with poor welding or even be unable to be welded to the top of the box body. The following method 2 or method 3 can be used.

[0064] 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 battery cell shell is compensated by the deformation of the weak portion, so that the polarity terminals of all battery cells 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 battery cells 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.

[0065] 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 battery 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 battery 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 top outer surface 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 battery cell used to insulate the pole avoidance hole and the top cover.

[0066] Example 2

[0067] like Figure 4 and Figure 5 As shown, this embodiment is based on the embodiment 2, and the large-capacity battery adds a gas communication channel 400, and the gas area of ​​each battery cell is connected through the gas communication channel 400, so that each battery cell is in the same gas pressure environment, and at the same time, an electrolyte communication channel 500 is added to make the electrolyte liquid level continuity better (avoid the situation of liquid interruption) when the electrolyte areas of each battery cell are connected;

[0068] In order to realize that each battery cell 200 can be connected through the gas communication channel 400, as shown in FIG. Figure 6 As shown, in this embodiment, a second sealing opening piece 5 needs to be provided on the top cover of each battery cell; the structure of the second sealing opening piece 5 is consistent with the first sealing opening piece 2, and after the second sealing opening piece 5 is opened, an air hole is formed on the battery cell housing, so that the gas areas of each battery cell can be connected;

[0069] The second sealing opening component 5 can be installed on the battery cell shell in advance during the battery cell manufacturing process, or the finished battery cell can be modified by first opening an air hole on the finished battery cell and then installing the second sealing opening component at the air hole.

[0070] Moreover, the gas communication channel 400 is arranged at the top of the box body, and the following improvements need to be made based on the three box body forms given in Example 1:

[0071] In the first and second box forms: the first cover plate is integrally formed with a groove body protruding upward, and the groove body serves as a gas communication channel 400;

[0072] In the third box form: a groove body protruding upward is integrally formed on the top of the cylinder, and the groove body serves as a gas communication channel 400.

[0073] Example 3

[0074] See also Figure 1 and Figure 4 As shown, this embodiment is an improvement made on the basis of Embodiment 2 and Embodiment 3, and a heat exchange tube 600 is added to the large-capacity battery;

[0075] A heat exchange tube mounting portion 6 is provided on the positive terminal 3 and the negative terminal 4 of each battery cell; the heat exchange tube 600 cooperates with the heat exchange tube mounting portion 6 on the positive terminal 3 and the negative terminal 4 of each battery cell to transfer the temperature of the electrode assembly in each battery cell 200 from the polarity terminal to the external temperature control device, thereby reducing the problem of overheating of the electrode assembly affecting the performance of large-capacity batteries. More importantly, direct temperature control of each electrode assembly reduces the probability of thermal runaway, thereby improving safety.

[0076] Specifically, the heat exchange tube mounting portion 6 in the present invention has two forms:

[0077] Method 1: A through hole is opened on the positive terminal 3 and the negative terminal 4. The through hole diameter size 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.

[0078] Method 2: grooves are provided on the top or side walls of the positive terminal 3 and the negative terminal 4; the width of the grooves needs to ensure that the heat exchange tubes are tightly clamped therein, so as to ensure the installation stability while also ensuring the heat transfer effect between the heat exchange tubes and the poles.

[0079] Since the positive terminal 3 and the negative terminal 4 of the battery cell are charged, in order to ensure safety, the heat exchange tube and the positive terminal 3 and the negative terminal 4 of the battery 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 terminals.

[0080] Specifically, the heat exchange tube 600 can be provided in the following ways:

[0081] 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 battery cell 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.

[0082] 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 battery cell and the external temperature control device. The cored heat pipe is an evaporation-condensation type heat exchange device, which realizes heat transfer by the state change of the working fluid in the pipe.

[0083] Since the heat transfer effect of the cored heat pipe is affected by the length of the cored heat pipe, when the number of battery 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 large capacity battery, characterized in that: Including a box body, a partition and a battery cell; There are N battery cells, N≥2; the N battery cells are arranged side by side in the box, and the inner cavity of the battery cell has an electrolyte area and a gas area; The electrolyte areas in the inner cavities of the battery cells are interconnected, so that the battery cells are in a shared electrolyte system; Avoidance holes are provided on the top plate of the box body corresponding to the polarity terminals of each battery cell; each battery cell polarity terminal extends out of the avoidance hole, and the top plate area of ​​the box body corresponding to the avoidance hole is fixedly sealed with the battery cell shell; The positive terminals of all battery cells are connected as a total positive electrode, and the negative terminals of all battery cells are connected as a total negative electrode; There are N-1 partitions, one partition is arranged between each adjacent battery cell, at least one partition is filled with a fire-fighting medium, at least one release hole is arranged on the partition filled with the fire-fighting medium, and a seal is fixedly covered on the release hole. After the seal melts at a set temperature, the fire-fighting medium overflows from the release hole into the box.

2. A large capacity battery according to claim 1, characterized in that: Seals are provided at the top and bottom of the partition filled with fire fighting medium.

3. A large-capacity battery according to claim 1, characterized in that: The sealing member is a polyethylene layer.

4. A large capacity battery according to claim 2, characterized in that: The wall thickness of the partition filled with fire fighting medium is 1 to 1.5 mm.

5. A large capacity battery according to any one of claims 1 to 4, characterized in that: The top of the box body is provided with a gas communication channel for connecting the gas areas of each battery monomer.

6. A large capacity battery according to claim 5, characterized in that: An electrolyte communication channel is arranged at the bottom of the box body.

7. A large capacity battery according to claim 6, characterized in that: It also includes a heat exchange tube; the heat exchange tube is matched with the mounting portion of each battery cell polarity terminal.

8. A large capacity battery according to claim 1, characterized in that: The fire-fighting medium is perfluorohexanone.

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