A single battery and a large capacity battery

Abstract

The application discloses a single battery and a large-capacity battery. The shell of the single battery is a plastic shell, a weak part is integrally arranged on an upper cover plate, the weak part is arranged close to the outside of a pole column fixing part, the shell has a first cavity for storing free electrolyte, a first recess and a first boss are arranged on the side wall of the cylinder corresponding to the first cavity, the first recess is used for inserting and fixedly connecting the first boss on another single battery, under the action of external force, the side wall of the cylinder and the first recess circumscribed by the first boss can be opened, then the first boss and the first recess are communicated with the first cavity. The single battery has low cost and light weight, the free electrolyte stored in the first cavity of each single battery can rapidly absorb heat through heat transfer, overheat of the battery is effectively prevented, the risk of thermal runaway is reduced, and the weak part is arranged close to the pole column position, so that controllable emission of thermal runaway smoke is realized.

Description

Technical Field

[0001] This invention belongs to the field of batteries, specifically a single-cell battery and a high-capacity battery. Background Technology

[0002] Chinese patent CN219658914U discloses a high-capacity battery, the structure of which is as follows: Figure 1 As shown, the battery includes a large-capacity battery body formed by several individual cells connected in parallel and a shared conduit located on the large-capacity battery. This shared conduit connects all the internal cavities of the individual cells, ensuring that all individual cells in the large-capacity battery are within a single system. This shared conduit enhances the uniformity of the individual cells within the large-capacity battery and improves cycle life.

[0003] The single battery in the aforementioned patent includes a housing, a sealing assembly, and a finished battery. The finished battery is installed inside the housing, and the housing has an opening. The housing has a first through hole communicating with the opening, and a pipe 01 extending along the width or length of the housing. The side wall of the pipe has a second through hole communicating with the first through hole. The sealing assembly is disposed on the opening, the first through hole, or the second through hole.

[0004] By setting a first through hole and a pipe with a second through hole on the outer casing of a single cell, a shared pipeline 02 can be formed through the pipe when assembling a large-capacity battery; moreover, by adding an outer casing to the finished battery, existing finished battery production lines can be used to put the finished battery into production with slight modifications.

[0005] However, this design has some drawbacks. Typically, both the finished battery casing and the outer shell are made of aluminum, which makes the overall cost of large-capacity batteries higher and their weight heavier.

[0006] From a cost perspective, aluminum is a relatively expensive metal. Furthermore, the manufacturing process for aluminum casings is complex, requiring multiple steps such as cutting, stamping, and welding, and demanding advanced equipment and techniques. These factors combined inevitably lead to a significant increase in the manufacturing cost of large-capacity batteries.

[0007] From a weight perspective, the stacking of two aluminum components significantly increases the overall weight of a large-capacity battery. This is extremely disadvantageous for the use, storage, and transportation of large-capacity batteries. Summary of the Invention

[0008] In order to overcome the problems of high cost and heavy weight of existing large-capacity batteries, the first aspect of the present invention provides a single-cell battery.

[0009] This single-cell battery includes a casing and electrode assembly; its improvements lie in:

[0010] The shell is a plastic shell, including a cylindrical body with open ends, an upper cover assembly fixedly sealed to the upper open end of the cylindrical body, and a lower cover plate fixedly sealed to the lower open end of the cylindrical body.

[0011] The housing has a first cavity and a second cavity; wherein at least a portion of the space in the first cavity is used to store free electrolyte; and the inner cavity of the second cavity is used to accommodate an electrode assembly.

[0012] The top cover assembly includes a top cover plate and a weak part integrally disposed on the top cover plate, and the weak part is located on the top cover plate near the electrode post; the strength of the weak part is less than the strength of the top cover plate, and in the event of thermal runaway of a single cell, the thermal runaway smoke breaks through the weak part and is discharged.

[0013] A recess and a protrusion are provided on the side wall of the housing corresponding to the first cavity; wherein the first recess is used for the insertion of the first protrusion on another single battery cell and for sealing connection; under the action of external force, the cylindrical side wall enclosed by the first protrusion and the first recess can be opened, thereby making the first protrusion and the first recess communicate with the first cavity.

[0014] The weak part of the present invention is integrally disposed on the upper cover plate and closely attached to the pole post fixing part, which has at least the following advantages:

[0015] From a structural stability perspective, existing explosion-proof membranes are typically attached to the battery cover plate via adhesive or other methods. During long-term use, factors such as corrosion from internal battery chemicals, temperature changes, and mechanical vibrations can cause the connection between the explosion-proof membrane and the cover plate to loosen or detach, leading to a failure of its explosion-proof function. In contrast, the integrated weak point in this invention is a single unit with the cover plate, eliminating the risk of loosening or detachment at the connection point. This significantly improves structural stability and reliability, ensuring consistently excellent explosion-proof performance.

[0016] In terms of sealing, achieving an absolute seal at the junction of the existing explosion-proof membrane and the top cover faces numerous challenges. However, the seamless integration of the integrated weak point with the top cover effectively ensures the internal sealing of the battery under normal conditions, preventing the intrusion of external substances and providing a better environment for stable battery operation.

[0017] From a cost and manufacturing process perspective, existing explosion-proof membranes require additional materials and complex installation processes, which not only increases production costs but may also lead to inconsistent product quality due to human factors during manufacturing. In contrast, the integrated design of the weak point eliminates the need for additional installation steps during manufacturing, simplifying the production process, reducing production costs, and improving product consistency and quality stability.

[0018] From a practical application perspective, since the terminal temperature of a single battery is high during operation, when a thermal runaway occurs in an existing single battery, the thermal runaway gas may overflow not only from the explosion relief membrane but also from the area around the terminal, making the thermal runaway gas uncontrollable. This invention replaces the explosion relief membrane of the existing single battery with a weak part and places it directly in the area near the terminal. The thermal runaway gas can only overflow from the area around the terminal, improving the controllability of thermal runaway.

[0019] The single-cell battery casing in this invention is made of plastic, and the casing has internal partitions and is equipped with inserts, which has at least the following advantages:

[0020] The single-cell battery in this invention fully utilizes the first cavity within its casing to store a large amount of free electrolyte. This electrolyte possesses a certain thermal conductivity; during battery operation, if the temperature rises, the free electrolyte stored in the first cavity can rapidly absorb heat through heat transfer, dispersing the absorbed heat throughout the entire battery casing and dissipating it through the casing surface. This effectively prevents battery overheating, reduces the risk of thermal runaway, precisely regulates temperature, and maintains battery performance.

[0021] Furthermore, the first and second cavities are interconnected, allowing the electrolyte to flow and diffuse freely throughout the casing. When the electrode assembly is operating, electrolyte consumption can be replenished promptly, preventing localized drying, ensuring stable internal battery reactions, and improving charge / discharge performance.

[0022] In addition, when using this single cell to assemble a large-capacity battery, the present invention can also use tools to open the cylindrical area and the first recess defined by the first protrusion of each single cell. In this way, gas balance and / or electrolyte sharing can be achieved between the individual cells, and the differences that may exist can be effectively improved, ensuring the consistency of each individual cell during the charging and discharging process, extending the overall service life, and improving the performance of the large-capacity battery.

[0023] Furthermore, the casing component of the single-cell battery provided by the present invention is made of plastic, which has advantages such as simple structure, low cost and light weight compared with the single-cell battery with double casing used in the prior art.

[0024] Furthermore, a groove is formed around the lower surface of the upper cover, in the area immediately surrounding the terminal post fixing part, creating a weak point. Compared to some methods that create weak points by changing material composition or microstructure, setting a groove is simpler and allows for more intuitive and precise control over the strength and opening pressure of the weak point. Specifically, by controlling parameters such as the depth and width of the groove, the opening of the weak point under a specific pressure can be accurately set, greatly improving the reliability of the explosion venting function. Moreover, the groove on the lower surface of the upper cover does not affect the overall appearance of the battery and avoids the safety hazards that would arise if air dust and moisture were trapped on the upper cover when the groove is on the upper surface.

[0025] Furthermore, to prevent the pole from collapsing due to the full opening of the weak points during thermal runaway, at least three connecting ribs are arranged circumferentially within the aforementioned groove. These connecting ribs can support the pole even after the weak points have fully opened.

[0026] Furthermore, the present invention can employ injection molding to integrally form the first recess and the first protrusion on the shell. The processing is simple. Since the first recess and the first protrusion are formed simultaneously with the shell, there is no problem of dimensional deviation caused by subsequent assembly. The precision is high, which can ensure that the first recess and the first protrusion of each individual battery can be precisely matched, which is beneficial to the mass production and quality control of large-capacity batteries.

[0027] Furthermore, the first recess and the first protrusion are connected by a heat-fusion method. During the heat-fusion process, the plastic material melts upon heating, and upon cooling and solidification, the materials of the recess and the protrusion fuse together to form a single, integrated structure, creating a very strong bond between them. This connection method can withstand significant tensile, compressive, and shear forces, effectively preventing loosening or separation of individual battery cells during use and ensuring the structural stability of high-capacity batteries. Simultaneously, heat-fusion connection has lower precision requirements; even with certain dimensional deviations between the first recess and the first protrusion during production, a precise connection can still be achieved, greatly improving production efficiency.

[0028] Furthermore, the strength of the aforementioned casing is P, where P1 ≤ P ≤ P2; where P1 represents the strength requirement of the casing during the formation stage and normal charge / discharge stages; and P2 represents the strength requirement of the casing during the thermal runaway stage. The aforementioned single-cell battery casing is a sealed casing made of plastic, serving as a containment cavity for the electrode components and electrolyte, providing a sealing function. Simultaneously, the strength of the sealed casing must meet the strength requirements during the formation stage and normal charge / discharge stages; that is, the sealed casing must possess sufficient strength to ensure that it will not rupture during the formation stage and normal charge / discharge stages, despite changes in the internal battery environment, such as temperature and pressure. Compared to existing finished plastic-cased single-cell batteries, this single-cell battery has a lower cost, thereby reducing the overall cost of the large-capacity battery.

[0029] Furthermore, the first chamber and the second chamber can be arranged along the width direction of the single cell. Correspondingly, the first recess and the first protrusion are located on two opposite large surfaces of the cylinder and extend along the height direction of the cylinder.

[0030] When constructing a large-capacity battery using this single cell, by increasing the width and height dimensions of the first recess and the first protrusion, the contact area between the first recess and the first protrusion is significantly increased, greatly improving the structural stability after nesting. Furthermore, the requirements for machining precision are further reduced. Multiple first and second blind holes are arranged along the height direction of the cylinder. The corresponding blind holes near the upper cover assembly, when opened at the bottom, allow gas communication between the individual cells, balancing the internal gas pressure of each cell. Similarly, the corresponding blind holes near the lower cover plate, when opened at the bottom, allow electrolyte communication between the individual cells, improving the consistency of each individual cell.

[0031] In this invention, the "connection" and "internal cavity communication" of a single battery cell are achieved through two independent structures: a first recess and a first boss, and a first blind hole and a second blind hole. Since the size of the first recess and the first boss is larger than that of the first blind hole and the second blind hole, they can be quickly aligned coaxially during insertion to complete a nested connection. After connection, even if there is a positional deviation between the first blind hole and the second blind hole on different axes, as long as there is a certain overlap in the projection areas of the first blind hole and the second blind hole, they can still be opened smoothly and connected. This significantly reduces the requirements for the processing accuracy of the first blind hole and the second blind hole, and reduces production difficulty and cost.

[0032] Furthermore, to ensure more reliable positioning of the large-capacity battery assembled from these individual cells, the present invention also provides a second recess and a second protrusion on the two opposite side walls of the cylinder corresponding to the second cavity; wherein the second recess is used for inserting and fixing the second protrusion on another individual cell. The structure and dimensions of the second recess and the second protrusion can be the same as those of the first recess and the first protrusion, except that blind holes are not provided in the second recess and the second protrusion.

[0033] A second aspect of the present invention provides a high-capacity battery, comprising a housing and n individual battery cells, wherein n is an integer greater than 1;

[0034] It includes a pressure-bearing housing and n individual batteries as described in the first aspect, where n is an integer greater than 1;

[0035] n individual cells are arranged inside the pressure tank, and there is a venting channel between the weak part of each individual cell and the pressure tank.

[0036] The pressure tank meets the compressive strength requirements during thermal runaway. It is equipped with a venting section corresponding to the venting channel. During thermal runaway of a single battery cell, the runaway gas ruptures through weak points and passes through the venting section.

[0037] The explosion channel is ruptured, and then the explosion vent is broken through the pressure box to discharge the contents.

[0038] For each pair of adjacent individual cells, the first protrusion of one individual cell is inserted into the first recess of the other individual cell and sealed together. After the recesses and protrusions of the adjacent individual cells are opened, the internal cavities of each individual cell are interconnected, and the first recesses and first protrusions of the first and last individual cells must remain sealed to the internal cavity of the pressure tank.

[0039] The casing of the high-capacity battery of this invention is a pressure-bearing casing, which requires the pressure-bearing casing to have good strength to ensure that during the thermal runaway stage, the pressure-bearing casing can form a solid barrier, effectively isolate high-temperature flames and harmful gases, prevent the spread of thermal runaway, and improve the safety of the high-capacity battery after thermal runaway.

[0040] Meanwhile, in this invention, by using a tool to open the cylindrical area and the first recess defined by the first protrusion of each individual battery, gas balance and / or electrolyte sharing can be achieved between the individual batteries. The differences that may have existed can be effectively improved, ensuring the consistency of each individual battery during the charging and discharging process, extending the overall service life, and improving the performance of large-capacity batteries.

[0041] Furthermore, in the aforementioned high-capacity battery, the first protrusion of one individual cell is inserted into the first recess of another individual cell and fixedly connected by heat fusion.

[0042] Furthermore, the aforementioned second blind hole is a stepped blind hole, allowing a sealing ring to be embedded within the larger section of the stepped blind hole. After the first recess and the first boss are interlocked, the sealing ring is pressed tightly into the gap between the first and second blind holes, forming an effective seal. This prevents the seal between the first recess and the first boss from failing, which could lead to electrolyte leakage or external gas intrusion.

[0043] Furthermore, in each pair of adjacent individual cells, the second protrusion of one cell is inserted into the second recess of the other cell, and the connection is secured by heat fusion. During the heat fusion process, the plastic material melts upon heating, and upon cooling and solidification, the materials of the first recess and the first protrusion fuse together to form a single, integrated structure, creating a very strong bond between them. This connection method can withstand significant tensile, compressive, and shear forces, effectively preventing loosening or separation of individual cells during use, ensuring the structural stability and sealing of high-capacity batteries. Simultaneously, heat fusion connection has lower precision requirements; even with certain dimensional deviations between the first recess and the first protrusion during production, a precise connection can still be achieved, greatly improving production efficiency.

[0044] Furthermore, the top plate of the aforementioned pressure-bearing housing has clearance holes corresponding to the terminals of each individual battery; each individual battery terminal extends out of the clearance holes; the area of ​​the top plate of the housing corresponding to the clearance holes is fixedly sealed to the top cover of the individual battery. In this invention, the terminals of each individual battery extending out of the pressure-bearing housing facilitates the electrical connection between individual batteries, as well as the electrical connection between the large-capacity battery itself and external electrical equipment;

[0045] Furthermore, a first insulating sealant layer is provided between each individual battery cell inside the pressure-bearing box, and between each individual battery cell and the box.

[0046] Furthermore, the aforementioned battery pack also includes a heat exchange component; the portion of each individual battery terminal extending out of the pressure-bearing housing cooperates with the heat exchange component to achieve temperature control of each individual battery; a second insulating sealant layer is laid on the top of the pressure-bearing housing, and at least a portion of the structure of the heat exchange component is located within the second insulating sealant layer.

[0047] During battery pack operation, heat can easily accumulate at the terminals due to current conduction. Heat exchange components can promptly remove this heat, ensuring the terminals remain within a suitable operating temperature range. This not only helps maintain the stable performance of individual cells within the battery pack and reduces performance degradation caused by excessive temperature, but also further enhances the overall safety and reliability of the battery pack, preventing potential malfunctions caused by localized overheating. The heat exchange components are partially located within the second insulating sealant layer, which also prevents condensation on the surface of the heat exchange components from potentially causing short circuits.

[0048] The beneficial effects of this invention are:

[0049] First, the weak part of the present invention is integrally formed on the upper cover plate, and the weak part is set close to the outside of the pole post fixing part, which has at least the following advantages:

[0050] High structural stability;

[0051] Existing explosion-proof membranes are typically attached to the battery cover using adhesive or other methods. During long-term use, factors such as corrosion from internal battery chemicals, temperature changes, and mechanical vibrations can cause the connection between the membrane and the cover to loosen or detach, leading to a failure of its explosion-proof function. In contrast, the integrated weak point in this invention is a single unit with the cover, eliminating the risk of loosening or detachment. This significantly improves the structural stability and reliability, ensuring consistently excellent explosion-proof performance.

[0052] It has good sealing performance and low manufacturing cost;

[0053] Achieving a perfect seal at the junction of the existing explosion-proof membrane and the top cover plate presents numerous challenges and requires significant costs. In contrast, the present invention integrates the weak point seamlessly with the top cover plate, ensuring excellent sealing performance. Furthermore, by eliminating the need for additional installation steps during manufacturing, it simplifies the production process, reduces production costs, and improves product consistency and quality stability.

[0054] Thermal runaway flue gas can be emitted in a controlled manner, ensuring high safety.

[0055] From a practical application perspective, since the terminal temperature of a single battery is high during operation, when a thermal runaway occurs in an existing single battery, the thermal runaway gas may overflow not only from the explosion relief membrane but also from the area around the terminal, making the thermal runaway gas uncontrollable. This invention replaces the explosion relief membrane of the existing single battery with a weak part and directly sets it in the area close to the terminal. The thermal runaway gas can only overflow from the area around the terminal, improving the controllability of thermal runaway.

[0056] The single-cell battery casing in this invention is made of plastic, and the casing has internal partitions and is equipped with inserts, which has at least the following advantages:

[0057] The single-cell battery in this invention fully utilizes the first cavity within its casing to store a large amount of free electrolyte. This electrolyte possesses a certain thermal conductivity; during battery operation, if the temperature rises, the free electrolyte stored in the first cavity can rapidly absorb heat through heat transfer, dispersing the absorbed heat throughout the entire battery casing and dissipating it through the casing surface. This effectively prevents battery overheating, reduces the risk of thermal runaway, precisely regulates temperature, and maintains battery performance.

[0058] Furthermore, the first and second cavities are interconnected, allowing the electrolyte to flow and diffuse freely throughout the casing. When the electrode assembly is operating, electrolyte consumption can be replenished promptly, preventing localized drying, ensuring stable internal battery reactions, and improving charge / discharge performance.

[0059] In addition, when using this single cell to assemble a large-capacity battery, the present invention can also use tools to open the cylindrical area and the first recess defined by the first protrusion of each single cell. In this way, gas balance and / or electrolyte sharing can be achieved between the individual cells, and the differences that may exist can be effectively improved, ensuring the consistency of each individual cell during the charging and discharging process, extending the overall service life, and improving the performance of the large-capacity battery.

[0060] Furthermore, the casing component of the single-cell battery provided by the present invention is made of plastic, which has advantages such as simple structure, low cost and light weight compared with the single-cell battery with double casing used in the prior art.

[0061] Meanwhile, to improve the safety performance of large-capacity batteries constructed from the aforementioned individual cells, this invention places multiple individual cells within a pressure-bearing enclosure. In extreme cases where a single cell experiences thermal runaway and its plastic casing melts, this pressure-bearing enclosure forms a robust thermal barrier, effectively isolating high-temperature flames and harmful gases, and preventing the spread of thermal runaway. Furthermore, protecting multiple individual cells with a pressure-bearing enclosure reduces external impacts and damage during transportation and use, extending battery life. Compared to the prior art structure where each individual cell is individually encased, this reduces individual packaging and protection costs, resulting in lower overall costs. Moreover, given the same number of individual cells, the weight of a single pressure-bearing enclosure is necessarily less than the weight of multiple small enclosures; therefore, the design of the pressure-bearing enclosure further reduces the weight of large-capacity batteries. Attached Figure Description

[0062] Figure 1 This is a schematic diagram of the structure of a large-capacity battery in the background art;

[0063] Figure 2 This is a schematic diagram of the structure of a single cell in Example 1;

[0064] Figure 3 This is a schematic diagram of the cylindrical body in Example 1. Figure 1 ;

[0065] Figure 4 This is a schematic diagram of the cylindrical body in Example 1. Figure 2 ;

[0066] Figure 5 This is a schematic diagram of the upper cover assembly in Example 1. Figure 1 ;

[0067] Figure 6 This is a schematic diagram of the upper cover assembly in Example 1. Figure 2 ;

[0068] Figure 7 This is a cross-sectional view of the upper cover assembly in Embodiment 1;

[0069] Figure 8 This is a schematic diagram of the structure of a single cell in Example 2;

[0070] Figure 9 This is a schematic diagram of the cylinder structure in Example 2. Figure 1 ;

[0071] Figure 10 This is a schematic diagram of the cylinder structure in Example 2. Figure 2 ;

[0072] Figure 11 This is a schematic diagram of the cylinder structure in Example 3. Figure 1 ;

[0073] Figure 12 This is a schematic diagram of the cylinder structure in Example 3. Figure 2 ;

[0074] Figure 13 This is a schematic diagram of the structure of the high-capacity battery in Example 4;

[0075] Figure 14 This is a schematic diagram of the explosion structure of the large-capacity battery in Example 4;

[0076] Figure 15 This is a schematic diagram of the internal structure of the large-capacity battery in Example 4 after the pressure-bearing box has been removed;

[0077] Figure 16 This is a schematic diagram of the internal structure of the large-capacity battery in Example 5 after the pressure-bearing casing has been removed. Figure 1 ;

[0078] Figure 17 This is a schematic diagram of the internal structure of the large-capacity battery in Example 5 after the pressure-bearing casing has been removed. Figure 2 ;

[0079] Figure 18 This is a schematic diagram of the explosion structure of the large-capacity battery in Example 6.

[0080] The attached figures are labeled as follows:

[0081] 01. Pipeline; 02. Shared pipeline;

[0082] 1. Shell; 10. Cylinder; 101. First chamber; 102. Second chamber; 11. First recess; 12. First boss; 13. First blind hole; 14. Second blind hole; 15. Third boss; 16. Fourth boss; 17. Second recess; 18. Second boss; 19. Annular protrusion; 20. Top cover assembly; 201. Top cover plate; 202. Weak part; 2021. Groove; 203. Terminal post; 204. Liquid injection mechanism; 2041. Liquid injection channel; 2042. Sealing plug; 2043. Sealing piece; 30. Lower cover plate; 100. Single cell; 200. Pressure tank; 300. Explosion vent; 400. Heat exchange component; 500. Clearance hole. Detailed Implementation

[0083] 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.

[0084] 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.

[0085] In the description of this invention, it should be noted that the terms "top," "bottom," etc., indicating orientation or positional relationships are based on the orientation or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the 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, and therefore should not be construed as a limitation of the invention. Furthermore, the terms "first," "second," "third," "fourth," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0086] Example 1

[0087] This embodiment provides a single-cell battery 100, such as Figure 2 As shown, it includes a housing 1 and an electrode assembly; its improvement lies in:

[0088] The housing 1 is a plastic housing, including a rectangular cylindrical body 10 with open top and bottom ends, an upper cover assembly 20 fixedly sealed to the upper open end of the cylindrical body, and a lower cover plate 30 fixedly sealed to the lower open end of the cylindrical body 10; in this embodiment, the upper cover assembly of the single battery has two terminals, namely a positive terminal and a negative terminal.

[0089] It should be noted that the plastic material of the plastic casing should have the following properties:

[0090] First, it must have sufficient strength to ensure the stability of the battery structure;

[0091] Second, it has chemical corrosion resistance and can resist the corrosion of electrolytes;

[0092] Third, it has barrier properties, which can effectively prevent the electrolyte, gas and other substances inside the battery from leaking out, and at the same time prevent external impurities such as moisture and oxygen from entering the battery.

[0093] Fourth, it possesses excellent thermal stability. Batteries generate heat during charging and discharging, especially at high rates. This plastic material needs to maintain stable performance within a certain temperature range and will not soften, deform, or decompose due to high temperatures.

[0094] The plastic material used can be the same material used in existing plastic-cased single-cell batteries, or the plastic material disclosed in Chinese patents CN106543551A and CN106977894A.

[0095] The plastic shell can be molded in one piece using injection molding, eliminating the need for separate processing and assembly. This significantly reduces production steps and shortens the production cycle. Moreover, the injection-molded integral part ensures uniform material distribution and tight bonding during the molding process, resulting in a stronger connection between the lower cover plate and the cylinder, and higher overall structural strength.

[0096] like Figure 3 and 4 As shown, according to different functions, the inner cavity of the cylinder 10 is divided into two interconnected chambers, which are defined as the first chamber 101 and the second chamber 102, respectively; wherein at least part of the space of the first chamber 101 is used to store free electrolyte; and the second chamber 102 is used to accommodate the electrode assembly.

[0097] To clearly define the boundaries between the two chambers and ensure their respective functions, a dividing element can be installed inside the cylinder 10 to isolate them. This dividing element must meet two requirements simultaneously: firstly, it must have an electrolyte flow channel to ensure that the electrolyte in the first chamber 101 can flow smoothly into the second chamber 102; secondly, it must have structural limiting capabilities to fix the electrode assembly in the second chamber 102, preventing it from shifting during assembly or use and ensuring the stability of the battery structure.

[0098] It should be noted that the first chamber 101 and the second chamber 102 can be distributed along the width, thickness, or height direction of the individual battery 100. Here, the width, thickness, or height direction of the individual battery 100 refers to the width, thickness, or height direction of the cylindrical body, respectively. For ease of description, the width, thickness, and height directions of the individual battery 100 can be defined as the y-direction, x-direction, and z-direction, respectively.

[0099] If the first chamber 101 and the second chamber 102 are arranged according to the width and thickness directions of the single cell 100, then the space near the open end of the cylinder 101, which extends along the height direction of the single cell, is a gas zone, and the remaining space stores free electrolyte. If the first chamber 101 and the second chamber 102 are arranged according to the height direction of the single cell 100, and the first chamber 101 is located at the bottom of the cylinder 10 and extends along the width direction of the single cell, then the first chamber 101 is filled with electrolyte. If the first chamber 101 and the second chamber 102 are arranged according to the height direction of the single cell 100, and the first chamber 101 is located at the top of the cylinder 10 and extends along the width direction of the single cell, then the space near the open end of the first chamber 101 is a gas zone.

[0100] like Figure 3 and Figure 4 As shown, this embodiment mainly takes the arrangement of individual battery cells 100 along the width direction as an example.

[0101] On the two large surfaces (two side walls parallel to the yz plane) of the cylinder 10 corresponding to the first chamber 101, a first recess 11 and a first protrusion 12 are respectively provided. The first recess 11 is used for the insertion of the first protrusion 12 on another single battery 100 and for sealing connection.

[0102] As shown in the figure, in this embodiment, both the first recess 11 and the first boss 12 have rectangular structures, and their height and width are approximately the same as those of the first chamber 101. That is, the bottom end of the first recess is flush with the bottom end of the cylinder, and a certain assembly gap, such as 1mm or 2mm, can be reserved between the top end of the first recess 11 and the top end of the cylinder to facilitate the connection between the upper cover plate and the open end of the top of the cylinder. In some other embodiments, the bottom end of the first recess is flush with the bottom end of the cylinder, and the top end of the first recess 11 is also flush with the top end of the cylinder, meaning that the height of the first recess 11 and the cylinder are exactly the same, giving the first recess 11 its maximum dimension in the height direction.

[0103] In other embodiments, the first recess 11 and the first protrusion 12 may also adopt other structural forms such as trapezoids. Compared with the trapezoidal structure, the rectangular structure of this embodiment is more compatible with the first chamber 101, making the overall structure of the single battery 100 more regular. At the same time, after the two are connected, the single battery 100 is subjected to more uniform force.

[0104] The first recess 11 can adopt the following two structural forms depending on the wall thickness of the cylinder 10:

[0105] The first structure is suitable for scenarios where the wall thickness of the cylinder 10 is relatively thick. A recessed area towards the inner cavity is directly excavated on the outer wall of the cylinder 10.

[0106] The second structure is suitable for scenarios where the wall thickness of the cylinder 10 is relatively thin. An annular protrusion 19 can be provided on the side wall of the cylinder 10, and the area enclosed by the annular protrusion 19 is the first recess 11. Figure 4 As shown. If the wall thickness of the cylinder 10 is relatively thin, directly excavating the recess on the side wall would easily lead to further thinning of the wall thickness in the area corresponding to the first recess 11, resulting in insufficient rigidity. However, this structure does not require excessive reduction of the side wall thickness, and the annular protrusion 19 itself can enhance the structural strength of the recess area, providing a stable "slot foundation" for subsequent insertion with the first protrusion 12, and avoiding deformation of the first recess 11 during the insertion process.

[0107] like Figure 3 As shown, the first protrusion 12 is a rectangular protrusion that protrudes from the outer wall of the cylinder 10 away from the inner cavity of the cylinder 10. Its shape and size are adapted to the first recess 11, so that it can be inserted into the first recess 11 of another single battery 100 to achieve a fixed connection.

[0108] Since the height and width of the first recess 11 and the first protrusion 12 in this embodiment are similar to those of the first chamber 101, and the overall size is relatively large, it is convenient for the two to quickly achieve coaxial alignment and complete the nested connection when they are inserted.

[0109] In this embodiment, a first blind hole 13 and a second blind hole 14 are respectively provided on the first recess 11 and the first protrusion 12; under the action of external force, the bottom of the first blind hole 13 and the second blind hole 14 can be opened, thereby enabling the first blind hole 13 and the second blind hole 14 to communicate with the first chamber 101.

[0110] from Figure 3 and Figure 4As can be seen from the diagram, in this embodiment, there are four first blind holes 13 and four second blind holes 14, which are evenly arranged along the height direction of the cylinder 10. Specifically, the blind holes near the open end of the cylinder 10, when opened at the bottom, allow gas communication between the individual cells 100, balancing the internal gas pressure of each cell. The blind holes further away from the open end of the cylinder 10, when opened at the bottom, allow electrolyte communication between the individual cells 100, improving the consistency of each individual cell 100. In practical applications, the bottom of the corresponding blind holes can be opened according to actual needs.

[0111] In other embodiments, the number of the first blind hole 13 and the second blind hole 14 can be adjusted according to actual needs; alternatively, a single elongated blind hole can be used instead of multiple independent blind holes. However, compared to the multi-blind hole design in this embodiment, the elongated blind hole will result in a larger amount of material removal from the cylinder 10 in that area, weaker structural strength, and a greater susceptibility to deformation under stress.

[0112] In addition, from Figure 3 It can also be seen that the second blind hole 14 in this embodiment is a stepped blind hole, in which a sealing ring can be embedded. After the first recess 11 and the first boss 12 are connected by interlocking, the sealing ring will be pressed into the gap between the first blind hole 13 and the second blind hole 14 to form an effective seal, thereby avoiding the problem of electrolyte leakage or external gas intrusion caused by the failure of the interlocking seal between the recess and the boss.

[0113] Preferably, such as Figure 4 As shown, in this embodiment, a third protrusion 15 may be provided in the area of ​​the inner wall of the cylinder 10 corresponding to the first recess 11, and the first blind hole 13 extends inward to the third protrusion 15; a fourth protrusion 16 may be provided in the area of ​​the inner wall of the cylinder 10 corresponding to the first protrusion 12, and the second blind hole 14 extends inward to the fourth protrusion 16; the area between the third protrusion 15 and the fourth protrusion 16 serves as the first chamber 101.

[0114] The third protrusion 15 and the fourth protrusion 16 have multiple functions: First, when the bottom of the first blind hole 13 and the second blind hole 14 are opened with a tool, the third protrusion 15 and the fourth protrusion 16 can serve as internal support structures for the blind holes, effectively resisting the local impact force applied by the tool and preventing the hole diameter deformation and hole wall damage in the surrounding area of ​​the blind holes of the cylinder 10 due to uneven force. Second, when the first recess 11 and the first protrusion 12 are connected by insertion, they can strengthen the rigidity of the corresponding area from the inside of the cylinder 10, offset the compressive stress generated by insertion, prevent the side wall of the cylinder 10 from being recessed or deformed as a whole, and ensure the connection stability. Third, they can also help limit the electrode assembly in the second chamber 102, fix the position of the electrode assembly, prevent it from being displaced during assembly or use, ensure the stability of the electrode assembly, and thus ensure the reliability of the overall battery structure.

[0115] In this embodiment, the "connection" and "internal cavity communication" functions of the single cell 100 are separated into two independent structures: the "connection" is handled by the first recess 11 and the first protrusion 12, and the "internal cavity communication" is handled by the first blind hole 13 and the second blind hole 14, thus avoiding the precision pressure caused by the superposition of functions.

[0116] From the perspective of connection, the dimensions of the first recess 11 and the first boss 12 are much larger than those of the first blind hole 13 and the second blind hole 14. The large size design makes it easier and faster to achieve coaxial alignment when the two are inserted, making it easier to complete nested connections and ensuring connection stability. From the perspective of communication, since the connection is achieved independently by the structure of the first recess 11 and the first boss 12, the first blind hole 13 and the second blind hole 14 do not need to bear the positioning function. Even if there is a slight misalignment between the first blind hole 13 and the second blind hole 14 after connection, as long as the projection areas of the two overlap to a certain extent, gas or electrolyte communication can still be achieved normally after opening the bottom. This greatly reduces the requirements for the machining accuracy of the first blind hole 13 and the second blind hole 14, effectively reducing production difficulty and cost.

[0117] In traditional designs, blind holes are often used as a composite structure that is both connected and interconnected. Blind holes need to perform both positioning and connection functions. This requires that the blind holes of adjacent single cells 100 must be highly coaxial and precisely matched in size. Otherwise, problems such as "either misalignment or failure of connection" will occur. This results in extremely high requirements for the processing and assembly precision of blind holes, which not only increases the difficulty of the process but also increases the production cost.

[0118] In this embodiment, as Figures 5 to 7 As shown, the upper cover assembly 20 includes an upper cover plate 201 and an electrode post 203, which are mounted on the upper cover plate 201 through the electrode post fixing part. Unlike conventional upper cover assemblies, the present invention has an integrally formed weak part 202 on the upper cover plate 201, and the weak part 202 is set close to the outside of the electrode post fixing part. When thermal runaway occurs inside the single cell and the internal pressure reaches a certain requirement, the thermal runaway flue gas breaks through the weak part to form an opening and is discharged from the opening of the weak part.

[0119] Compared to conventional single-cell battery cover assemblies where the explosion vent membrane and cover plate are separate components, this invention integrates the cover plate and the weak point into one piece, with the weak point positioned close to the outer side of the electrode post fixing part, offering significant advantages:

[0120] First, in a split design, sealing the junction between the explosion-proof membrane and the top cover is challenging. It requires special sealants, complex sealing structures, and high-precision machining, resulting in high costs and complex processes. Even then, sealing failure can occur due to material aging, temperature changes, and other factors, leading to the failure of the explosion-proof function. In contrast, this invention features an integrated design with seamless connection, inherently possessing excellent sealing performance. It eliminates the risk of loosening or detachment at the connection points, significantly improving structural stability and reliability, and maintaining consistently good explosion-proof performance. Second, split designs require substantial investment to achieve optimal sealing. This integrated design avoids expensive sealing materials and complex installation processes, significantly reducing costs. This results in significant economic benefits during mass production. Furthermore, the integrated design reduces the scrap rate due to poor sealing, further lowering overall costs. Third, compared to split designs, the integrated design has a more uniform stress distribution at weak points, allowing for reliable opening under set pressure. This avoids premature opening or failure to open, providing more reliable protection for safe operation of the battery under extreme conditions and enhancing battery stability and safety. Fourth, the integrated design simplifies the top cover assembly structure, reduces the number of parts, and makes battery packaging more convenient and efficient. In contrast, separate manufacturing and reassembly sealing of individual components increases manufacturing uncertainty and quality control difficulty. Finally, due to the high terminal temperature during single-cell operation, existing single-cell thermal runaway systems can release runaway gases not only from the venting membrane but also from the surrounding area of ​​the terminal, making the runaway gases uncontrollable. This invention replaces the existing single-cell venting membrane with a weak point and places it directly near the periphery of the terminal, ensuring that runaway gases can only escape from the periphery of the terminal, thus improving the controllability of thermal runaway.

[0121] It should be noted that:

[0122] 1. The “pole post fixing part” mentioned above, which is “set close to the outside of the pole post fixing part”, actually refers to the component used to fix and seal the pole post and the upper cover plate. It can be a cast-in-place sealing layer or a cast-in-place sealing layer and fasteners as a whole.

[0123] 2. The strength of the aforementioned weak point is less than that of the rest of the top cover plate to ensure that, in the event of thermal runaway, this weak point is the first to open. However, the strength of the weak point cannot be too low either, ensuring that it will not deform or crack during the cell formation stage or normal operation, thus affecting battery performance. Therefore, during the design phase, it is necessary to comprehensively consider various stresses that the top cover plate will withstand during normal battery operation, including internal pressure and external vibration. By rationally designing the corresponding structural dimensions of the weak point, the structural stability of the top cover plate under normal operating conditions can be ensured, while also ensuring that the weak point can reliably perform its explosion-proof function in the event of thermal runaway.

[0124] Specifically, such as Figure 6As shown, in this embodiment, a groove 2021 is formed on the lower surface of the upper cover plate 201 by injection molding or machining in the area close to the periphery of the pole fixing part, serving as a weak part 202.

[0125] In some other embodiments, the weak portion may also be a fan-shaped recess, or a circular or rectangular recess;

[0126] Because plastic materials have weaker high-temperature resistance than metal materials, the high temperature of the electrode post makes it easier for the area around the electrode post to crack. Therefore, the design of placing the weak part in the area near the electrode post is more suitable for plastic top cover plates.

[0127] The depth and width of the groove 2021 can be set according to specific needs to ensure that the area of ​​the upper cover plate 201 where the bottom of the groove 2021 is located can be opened under the set pressure.

[0128] However, it is important to note that the depth and width of the groove 2021 should not be excessive. If the dimensions exceed a reasonable range, the groove 2021 may deform or even crack due to insufficient strength when the battery has not experienced thermal runaway (i.e., during formation and normal operation), thereby affecting battery performance. Therefore, during the design phase, it is necessary to comprehensively consider the various stresses that the top cover 201 will bear during normal battery operation, including internal pressure and external vibration. By rationally planning the corresponding dimensions of the groove 2021, while ensuring the structural stability of the top cover 201 under normal operating conditions, it is also ensured that the groove 2021 can reliably perform its explosion-proof function in the event of thermal runaway.

[0129] To prevent the pole post from collapsing after the groove breaks, in this embodiment, at least three connecting ribs are evenly distributed circumferentially within the groove 2021. Therefore, even if the groove breaks, the three connecting ribs can still provide a connection force between the pole post and the upper cover plate 201, reducing or even avoiding the possibility of the pole post 203 collapsing and improving safety.

[0130] As is well known, during the operation of a single battery cell, the temperature of the positive electrode post is higher than that of the negative electrode post. In principle, the probability of cracking in the area around the positive electrode post in the upper cover is higher than that in the area around the negative electrode post. Therefore, in this embodiment, the weakest part is preferably located near the positive electrode post.

[0131] In this embodiment, as Figure 7 As shown, the upper cover assembly is also provided with a liquid injection mechanism 204, which includes a liquid injection channel 2041, a sealing plug 2042, and a sealing piece 2043. The liquid injection channel 2041 is a hollow cylinder integrally formed on the upper cover plate 201 and facing the inside of the single cell. The lower end of the hollow cylinder is the liquid outlet, and the upper end is the liquid inlet. The sealing plug 2042 is installed in the liquid injection channel 2041, and the sealing piece 2043 is fixed to the liquid inlet by heat fusion.

[0132] The sealing plug 2042 and the sealing piece 2043 constitute two seals at the injection channel. The practical reason for this is:

[0133] 1. The double seals are more reliable, and thermal runaway flue gas will not leak from this point in the event of thermal runaway, further improving the controllability of thermal runaway flue gas.

[0134] 2. In addition to the initial liquid injection, a second liquid replenishment may be required before the finished single cell leaves the factory. Therefore, during the initial liquid injection and the second liquid replenishment process, a sealing plug can be used as a temporary seal, and the sealing sheet can be heat-fused to fix it in the final stage.

[0135] Preferably, in order to further reduce costs, the strength of each individual battery casing in this embodiment meets certain requirements. In this embodiment, the casing strength is not required to meet the strength requirements during the thermal runaway stage; it only needs to meet the strength requirements during the formation stage and the normal charge / discharge process. During the formation stage and the normal charge / discharge process, the battery undergoes a series of chemical reactions and physical changes. During this process, certain pressure and heat are generated inside the battery. The casing needs to have sufficient strength to withstand this pressure and heat to ensure the smooth progress of the formation process and the normal use of the battery.

[0136] We can assume that the strength of the casing is P, P1≤P≤P2; where P1 is the strength requirement of the casing during the formation stage and the normal charging and discharging stage of the battery; and P2 is the strength requirement of the casing during the thermal runaway stage.

[0137] Under the premise of meeting the above strength requirements, in this embodiment, the thickness of the shell 1 (cylinder, upper cover plate, and lower cover plate) is h, where h is less than h0, and h0 is the thickness of a traditional single-cell battery plastic shell; the thickness of a traditional single-cell battery plastic shell is typically 5-8 mm. In this embodiment, the shell thickness can be between 1-4 mm. By reducing the thickness of the shell of a traditional single-cell battery with a plastic shell, better heat dissipation can be achieved, while also increasing the battery energy density. In addition, reducing the thickness of the plastic shell means using less plastic material, which helps save material costs and provides an economic advantage for large-scale production and application.

[0138] Example 2

[0139] like Figures 8 to 10As shown, unlike Embodiment 1, this embodiment adds a second recess 17 and a second protrusion 18 to the outer walls of the two cylindrical bodies 10 (parallel to the yz plane) of the second chamber 102, based on the single-cell battery of Embodiment 1. The second recess 17 is used to insert the second protrusion 18 of another single-cell battery 100 and fix it in place. By fixing adjacent single-cell batteries 100 from different parts of the cylindrical bodies 10, uneven force distribution at a single connection point can be avoided, significantly improving the overall connection strength.

[0140] Preferably, the second recess 17 and the second protrusion 18 are symmetrically distributed with the first recess 11 and the first protrusion 12.

[0141] Specifically, the second recess 17 and the second protrusion 18 are both located on the two opposite large surfaces of the cylinder 10 corresponding to the second chamber 102. Both are rectangular structures, and their height and width are similar to those of the second chamber 102.

[0142] Similar to the first recess 11, the second recess 17 can adopt the following two structural forms depending on the wall thickness of the cylinder 10:

[0143] The first structure is suitable for scenarios where the wall thickness of the cylinder 10 is relatively thick. A recessed area towards the inner cavity is directly excavated on the outer wall of the cylinder 10.

[0144] The second structure is suitable for scenarios where the wall thickness of the cylinder 10 is relatively thin. An annular protrusion can be provided on the side wall of the cylinder 10, and the area defined by the annular protrusion is the second recess 17. Figure 10 As shown. If the wall thickness of the cylinder 10 is relatively thin, directly excavating the recess on the side wall would easily lead to further thinning of the wall thickness in the area corresponding to the second recess 17, resulting in insufficient rigidity. However, this structure does not require excessive reduction of the side wall thickness, and the annular protrusion itself can enhance the structural strength of the recess area, providing a stable "slot foundation" for subsequent insertion with the second protrusion 18, and avoiding deformation of the second recess 17 during the insertion process.

[0145] like Figure 9 As shown, the second boss 18 is an annular protrusion protruding from the outer wall of the cylinder 10 away from the inner cavity of the cylinder 10. Its shape and size are adapted to the second recess 17, facilitating its insertion into the second recess 17 of another single battery cell 100 for fixed connection. Compared to the solid boss structure, the annular protrusion structure can reduce the amount of material used in the cylinder 10 while ensuring connection strength, thereby further reducing its overall weight and balancing structural reliability and lightweight requirements.

[0146] Example 3

[0147] like Figure 11 and Figure 12As shown, unlike Embodiment 1, in this embodiment, the first chamber 101 and the second chamber 102 within the casing 10 of the single battery are arranged along the height direction of the single battery 100, and the first chamber 101 is located at the bottom of the casing 10 (not shown in the figure). Correspondingly, the first recess 11 and the first protrusion 12 are also located near the bottom of the outer side wall of the large surface of the casing 10, extending along the width direction of the casing 10, and the height and width of the first recess 11 and the first protrusion 12 are approximately the same as those of the first chamber 101. The height and width directions here are consistent with the height and width directions of the casing 10.

[0148] There can also be four first blind holes 13 and four second blind holes 14, which are evenly arranged along the width direction of the cylinder 10. Corresponding to the blind holes, after the bottom is opened, the electrolyte between each individual cell 100 can be connected, improving the consistency of each individual cell 100.

[0149] Corresponding to the positions of the first recess 11 and the first protrusion 12 in this embodiment, similar to Embodiment 1, a third protrusion 15 is provided in the area of ​​the inner wall of the cylinder 10 corresponding to the first recess 11, and the first blind hole 13 extends inward to the third protrusion 15; a fourth protrusion 16 is provided in the area of ​​the inner wall of the cylinder 10 corresponding to the first protrusion 12, and the second blind hole 14 extends inward to the fourth protrusion 16; the area between the third protrusion 15 and the fourth protrusion 16 serves as the first chamber 101, and the functions of the third protrusion 15 and the fourth protrusion 16 are the same as in Embodiment 1, which will not be described again here.

[0150] The remaining structures, such as the structure and connection method of the first recess 11 and the first protrusion 12, the corresponding blind hole structure, and the material of the cylinder 10, are the same as in Embodiment 1, and will not be described again here.

[0151] Example 4

[0152] Based on the single-cell battery of Example 1, this embodiment provides a high-capacity battery, such as... Figure 13 , 14 As shown in Figure 15, it includes a pressure-bearing housing 200 and 12 individual battery cells 100. In other embodiments, the number of individual battery cells 100 can be adjusted according to actual needs.

[0153] Twelve individual battery cells 100 are installed in the pressure-bearing housing 200 by interlocking the first recess 11 and the first protrusion 12. In adjacent individual battery cells 100, the first protrusion of one individual battery cell 100 is inserted into the first recess of another individual battery cell 100 and fixedly connected by heat fusion. After the first blind hole 13 and the corresponding second blind hole 14 are opened with a tool, the inner cavities of each individual battery cell 100 are interconnected, and the first recess 11 and the first protrusion 12 of the first and last individual battery cells 100 must remain sealed.

[0154] To prevent electrolyte leakage or external gas intrusion caused by the failure of the seal between the first recess 11 and the first boss 12 during interlocking, a sealing ring can be embedded in the large hole section of the stepped second blind hole 14. When the first recess 11 and the first boss 12 are interlocked, the sealing ring is pressed into the gap between the first blind hole 13 and the second blind hole 14, forming a secondary effective seal. Even if there is a slight gap between the first recess 11 and the first boss 12, wear occurs on the mating surfaces after long-term use, or slight stress relaxation occurs at the connection due to temperature changes, the elastic deformation of the sealing ring can continuously fill the gap, preventing electrolyte leakage or external gas intrusion.

[0155] An explosion relief channel is provided between the pressure tank 200 and the cover assembly 11 of each individual battery 100, and an explosion relief part 300 communicating with the explosion relief channel is provided on the tank 200 (the explosion relief part here can also be called an explosion-proof part, explosion-proof port or explosion relief port, etc., and is usually equipped with a pressure relief valve or explosion relief membrane, etc.). When the individual battery is thermally runaway, the thermal runaway smoke breaks through the weak part 202, passes through the explosion relief channel, breaks through the explosion relief part 300 and is discharged from the pressure tank 200.

[0156] This embodiment uses the outer casing of the large-capacity battery as the core pressure-bearing casing. Simultaneously, plastic is used as the inner casing for each individual battery cell. This design not only effectively resists the high-pressure impact during thermal runaway thanks to the reinforced outer casing, greatly improving the overall safety of the large-capacity battery, but also reasonably reduces the production cost of the battery casing through the plastic casing, achieving a balance between safety and economy. Furthermore, an anti-seepage membrane can be installed between each individual battery cell and the pressure-bearing casing to prevent the electrolyte inside each individual battery cell from seeping out.

[0157] The pressure chamber 200 needs to meet the compressive strength requirements during the thermal runaway stage; that is, to ensure that during the thermal runaway stage, the pressure chamber can form a robust thermal barrier, and even in the extreme case of the individual battery casing melting, it can effectively isolate high-temperature flames and harmful gases, prevent the spread of thermal runaway, and improve the safety of large-capacity batteries after thermal runaway.

[0158] Compared to other materials, metal pressure tanks are more reliable in emergencies such as thermal runaway. They can withstand greater impact and destructive forces, reducing the likelihood of accidents and protecting the safety of personnel and surrounding equipment. In this embodiment, the pressure tank does not directly contact the electrolyte, so an iron, steel, or stainless steel shell can be used. Iron shells offer advantages in strength and cost, making them a viable option in scenarios where cost is a primary concern and strength requirements are not particularly stringent. Steel shells offer relatively high strength, providing more reliable protection for the battery and are suitable for applications with high safety and structural strength requirements. Stainless steel shells not only possess good strength properties but also excellent corrosion resistance, making them ideal for battery applications facing humid or corrosive environments. This effectively extends battery life and ensures stable operation in complex environments.

[0159] Example 5

[0160] Based on the single-cell battery of Embodiment 2, this embodiment provides a high-capacity battery. Compared to the high-capacity battery of Embodiment 4, which only connects the single-cell batteries 100 through the first recess 11 and the first protrusion 12, this embodiment provides a high-capacity battery. Figure 13 , 16 As shown in Figure 17, this embodiment uses two sets of structures—the first recess 11 and the first boss 12, and the second recess 17 and the second boss 18—to fix adjacent individual cells 100 together from the corresponding parts of the first chamber 101 and the second chamber 102 of the cylinder 10. This can more evenly distribute the compressive stress during the interlocking connection, completely avoiding the problem of stress concentration at a single connection point. This not only significantly improves the firmness of the connection between individual cells 100, but also provides a more stable structural foundation for the subsequent blind hole opening action, further enhancing the overall reliability of the large-capacity battery.

[0161] Example 6

[0162] To optimize the heat dissipation performance of the large-capacity batteries in Examples 4 and 5, such as Figure 18 As shown, this embodiment adds a heat exchange component 400 to the aforementioned high-capacity battery to exchange heat with the terminals. The terminals are a crucial connection between the battery's internal and external components; during charging and discharging, current flows through the terminals to enter and exit the battery. When heat is generated inside the battery, heat dissipation through the terminals provides a relatively direct heat conduction path. Heat can be quickly conducted from the battery's interior to the terminals, and then dissipated from the terminals to the external environment. Furthermore, since the terminals are typically located at the positive and negative terminals of the battery, these areas are often where heat is concentrated during charging and discharging. By dissipating heat from the terminals, the temperature of these critical components can be reduced more effectively.

[0163] In this embodiment, the top of the pressure box 200 is provided with clearance holes 500 corresponding to the positions of the terminals of each individual battery; the terminals of each individual battery extend out of the corresponding clearance holes 500, and the terminals and clearance holes 500 are insulated and sealed. Extending the terminals of the individual battery 100 out of the pressure box 200 facilitates the electrical connection between individual batteries and the electrical connection between large-capacity batteries and external devices.

[0164] One point that needs to be made here is:

[0165] In this embodiment, the single battery terminal post can be an extended terminal post integrally formed on the upper cover plate; or it can be a terminal post extension piece added to the conventional terminal post of an existing single battery. Whether it is an extended terminal post or an extended terminal post, the purpose is to make the single battery terminal post in this embodiment extend out of the clearance hole, thereby facilitating electrical connection and heat exchange with the heat exchange component.

[0166] Of course, in some other embodiments, the terminals of individual cells may not extend out of the housing. Instead, the electrical connections between all individual cells 100 and the connections of the heat exchange components are completed inside the pressure housing 200 first, and then the total circuit is extended to the outside of the pressure housing 200 through a unified lead-out terminal or wiring structure, and the inlet and outlet ends of the heat exchange components 400 are led out of the pressure housing.

[0167] To optimize the heat dissipation performance of the high-capacity battery, this embodiment can also add a heat exchange component 400 to exchange heat with the terminals 203. As a key component connecting the battery's internal and external components, the terminals 203 allow current to flow in and out of the battery during charging and discharging. When heat is generated inside the battery, heat dissipation through the terminals 203 provides a relatively direct heat conduction path. Heat can be quickly conducted from inside the battery to the terminals 203, and then dissipated from the terminals 203 to the external environment. Furthermore, since the terminals 203 are typically located at the positive and negative terminals of the battery, these areas are often where heat is concentrated during charging and discharging. By dissipating heat from the terminals 203, the temperature of these key components can be reduced more effectively.

[0168] The heat exchange component 400 can be a heat transfer tube; each individual cell's terminal post is provided with a through slot or through hole for installing the heat transfer tube; the heat transfer tube is fixed in the through slot or through hole of each individual cell's terminal post. Using the heat transfer tube on the terminal post, the heat generated inside the battery is conducted through the terminal post to the heat transfer tube, and then the heat transfer tube dissipates the heat, thus achieving heat dissipation for the battery.

[0169] The heat exchange component 400 can also be a heat exchange device, which is installed on top of each individual battery cell 10000. The electrode post penetrates the heat exchange device, with at least a portion of its structure located within the inner cavity of the heat exchange device and in direct contact with the heat exchange medium. Another portion of the electrode post is located outside the heat exchange device, serving as an electrical connection. The sidewall of the electrode post is sealed to the heat exchange device. This direct heat exchange method places a portion of the electrode post directly within the heat exchange medium flow cavity (inner cavity of the heat exchange device), allowing direct contact between the electrode post and the heat exchange medium, thus achieving heat exchange through a shorter heat exchange path. The heat exchange medium acts directly on the electrode post, improving the utilization efficiency of the heat exchange medium and enhancing the overall heat exchange efficiency of the battery.

[0170] In this embodiment, a first insulating sealant layer can also be provided between each individual battery cell 100 and between each individual battery cell 100 and the pressure-bearing housing 200. The first insulating sealant layer is laid in the space between each individual battery cell 100 and the pressure-bearing housing 200. When there is a gap between each individual battery cell 100, the insulating sealant liquid can also penetrate into the gap. Furthermore, a second insulating sealant layer is also laid on the top plate of the pressure-bearing housing 200, and the heat exchange component 400 is at least partially located within the insulating sealant layer.

[0171] In this embodiment, the first insulating sealant layer and the second insulating sealant layer have at least the following advantages:

[0172] 1. Prevent condensation;

[0173] During long-term use, due to the temperature difference between the inside and outside of the heat exchange component 400, condensation will form on the surface. When the condensation accumulates to a certain amount, it may cause a short circuit. By laying an insulating sealant layer to completely wrap the heat exchange component 400, when condensation forms on the surface of the heat exchange component 400, the battery short circuit can be prevented under the protection of the insulating sealant layer.

[0174] II. Further improve the stability of each individual battery cell 100 within the pressure tank;

[0175] The insulating sealant penetrates into the gaps between each individual battery cell 100 and between each individual battery cell 100 and the pressure vessel, which can further improve the stability of each individual battery cell 100 within the pressure vessel. Simultaneously, it can further improve the sealing performance after the first protrusion 12 and the first recess 11 are connected, preventing electrolyte leakage or external gas intrusion through the blind hole opened at the bottom due to seal failure of the first recess 11 and the first protrusion 12 connection.

Claims

1. A single-cell battery, comprising a casing and an electrode assembly; characterized in that: The shell is a plastic shell, including a cylindrical body with open ends, an upper cover assembly fixedly sealed to the upper open end of the cylindrical body, and a lower cover plate fixedly sealed to the lower open end of the cylindrical body. The housing has a first cavity and a second cavity; wherein at least a portion of the space in the first cavity is used to store free electrolyte; The inner cavity of the second chamber is used to house the electrode assembly; The top cover assembly includes a top cover plate and a weak part integrally disposed on the top cover plate, and the weak part is disposed close to the outside of the electrode post fixing part; the strength of the weak part is less than the strength of the top cover plate, and when the single cell thermal runaway occurs, the thermal runaway smoke breaks through the weak part and is discharged. A first recess and a first protrusion are provided on the side wall of the housing corresponding to the first cavity; wherein the first recess is used for the insertion of the first protrusion on another single battery cell and for sealing connection; under the action of external force, the cylindrical side wall enclosed by the first protrusion and the first recess can be opened, thereby making the first protrusion and the first recess communicate with the first cavity.

2. The single-cell battery according to claim 1, characterized in that: A groove is made on the lower surface of the upper cover plate, in the area close to the perimeter of the pole fixing part, to form a weak part.

3. The single-cell battery according to claim 2, characterized in that: At least three connecting ribs are evenly distributed along the circumference of the groove.

4. The single-cell battery according to claim 1, characterized in that: Both the first recess and the first protrusion are integral with the housing; the first recess is used for the insertion of the first protrusion of another single battery cell, and is fixedly connected by heat fusion.

5. The single-cell battery according to claim 1, characterized in that: The strength of the single-cell battery casing is P, where P1≤P≤P2; where P1 is the strength requirement of the casing during the formation stage and the normal charge and discharge stage of the battery; and P2 is the strength requirement of the casing during the thermal runaway stage.

6. The single-cell battery according to claim 1, characterized in that: The first chamber and the second chamber can be arranged along the width direction of the single cell. Correspondingly, the first recess and the first protrusion are respectively provided on the two opposite outer walls of the cylinder corresponding to the first cavity and extend along the height direction of the cylinder. The first recess is provided with a plurality of first blind holes arranged along the height direction of the single cell, and the first protrusion is provided with a plurality of second blind holes arranged along the height direction of the single cell and corresponding one-to-one with the first blind holes. Under the action of external force, the bottom of the first blind hole and the second blind hole can be opened, thereby connecting the first blind hole and the second blind hole with the first chamber.

7. The single-cell battery according to claim 1, characterized in that: A second recess and a second protrusion are respectively provided on the two opposite side walls of the cylinder corresponding to the second cavity; wherein the second recess is used for the insertion and fixed connection of the second protrusion on another single cell.

8. A high-capacity battery, characterized in that: It includes a pressure-bearing housing and n individual battery cells as described in any one of claims 1 to 7, where n is an integer greater than 1; n individual cells are arranged inside the pressure tank, and there is a venting channel between the weak part of each individual cell and the pressure tank. The pressure tank meets the compressive strength requirements during thermal runaway. It is equipped with a venting section corresponding to the venting channel. During thermal runaway of a single battery cell, the runaway gas ruptures through weak points and passes through the venting section. The explosion channel is ruptured, and then the explosion vent is broken through the pressure box to discharge the contents. For every two adjacent individual cells, the first protrusion of one individual cell is inserted into the first recess of the other individual cell and fixedly connected. Under the action of external force, the cylindrical side wall enclosed by the first protrusion and the first recess can be opened, thereby making the first protrusion and the first recess communicate with the first cavity; and the first blind hole and the second blind hole of the first and last individual cells remain sealed with the inner cavity of the pressure box.

9. The high-capacity battery according to claim 8, characterized in that: The first protrusion of one single cell is inserted into the first recess of another single cell and fixedly connected by heat fusion.

10. The high-capacity battery according to claim 8, characterized in that: The second blind hole is a stepped blind hole, and a sealing ring is provided in the large section of the stepped blind hole to achieve a seal between the second blind hole and the corresponding first blind hole.

11. The high-capacity battery according to claim 8, characterized in that: For every two adjacent cells, the second protrusion of one cell is inserted into the second recess of the other cell and fixedly connected by heat fusion.

12. The high-capacity battery according to any one of claims 8 to 11, characterized in that: The top plate of the pressure tank has clearance holes corresponding to the terminals of each individual battery; each individual battery terminal extends out of the clearance holes; the area of ​​the top plate of the pressure tank corresponding to the clearance holes is fixedly sealed to the top cover of the individual battery.

13. The high-capacity battery according to claim 12, characterized in that: A first insulating sealant layer is provided between each individual battery cell inside the pressure chamber, and between each individual battery cell and the chamber.

14. The high-capacity battery according to claim 13, characterized in that: It also includes heat exchange components; the portion of each individual battery terminal extending out of the pressure-bearing box cooperates with the heat exchange components to achieve temperature control of each individual battery; a second insulating sealant layer is laid on the top of the pressure-bearing box, and at least part of the structure of the heat exchange components is located within the second insulating sealant layer.

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