Cylinder for single battery, single battery, and battery pack

Abstract

The application discloses a cylinder for a single battery, a single battery and a battery pack, both upper and lower ends of the cylinder are open; the cylinder is internally provided with an electrolyte storage area and an electrode assembly containing area; a recess and a protrusion are arranged on the side wall of the cylinder corresponding to the electrolyte storage area; the application sets the recess and the protrusion on the cylinder of the single battery, when the battery pack is assembled, the stability of the single battery in the box can be improved, and the structure of the whole battery pack is more stable and durable. Meanwhile, the electrolyte storage area in the cylinder can store more free electrolyte, the electrolyte has certain heat conduction capacity, when the temperature rises during the operation of the battery, the free electrolyte stored in the electrolyte storage area can rapidly absorb heat through heat transfer, the absorbed heat is dispersed to the shell of the whole single battery, and is emitted through the surface of the shell, so that the battery overheating is effectively prevented, and the risk of thermal runaway is reduced.

Description

Technical Field

[0001] This invention belongs to the field of batteries, specifically a cylindrical body for a single battery, a single battery cell, and a battery pack. Background Technology

[0002] In a battery pack, individual cells are typically arranged close together. In everyday use, battery packs are inevitably subjected to vibrations or impacts. If the individual cells lack reliable connections, they will collide with each other inside the battery pack.

[0003] In the event of a collision, the most direct consequence is damage to the individual battery casing, breaking its original good sealing performance, allowing external moisture, dust, and other impurities to enter. Once these impurities enter the battery, they gradually corrode key components such as the electrolyte and electrodes, disrupting the originally stable chemical reaction environment inside the battery and directly interfering with its electrical performance.

[0004] Meanwhile, collisions can also trigger more serious internal problems. Due to the vibration and impact, the electrode materials and separators inside a single battery cell are highly susceptible to displacement or damage. Key parameters that play a decisive role in the electrochemical reaction, such as the contact area and spacing between electrodes, change accordingly, causing a sharp decline in the efficiency of the electrochemical reaction and making the battery's charge and discharge performance extremely unstable. As a result, individual batteries cannot operate collaboratively as they would under normal conditions, ultimately affecting the stability and reliability of the entire battery pack, causing numerous inconveniences and even potential safety hazards for users. Summary of the Invention

[0005] In order to overcome the technical problem of poor installation stability of individual cells in existing battery packs, the first aspect of the present invention provides a cylindrical body for a single cell, the upper and lower ends of which are open; the cylindrical body has an electrolyte storage area and an electrode assembly receiving area; a recess and a protrusion are provided on the side wall of the cylindrical body corresponding to the electrolyte storage area; wherein the recess is used for inserting the protrusion on another cylindrical body for a single cell and fixing it in place.

[0006] The present invention provides recesses and protrusions on the individual battery cells. When assembling the battery pack, the protrusion of one individual battery cell can be inserted into the recess of another individual battery cell and fixedly connected, thereby improving the stability of the individual battery cells in the housing and making the entire battery pack structure more stable and durable.

[0007] Meanwhile, the electrolyte storage area inside the casing can store a large amount of free electrolyte. Since electrolyte has a certain thermal conductivity, if the temperature rises during battery operation, the free electrolyte stored in the storage area can quickly absorb heat through heat transfer, dispersing the absorbed heat throughout the entire cell 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.

[0008] Furthermore, the electrolyte storage area and the electrode assembly housing area are interconnected, allowing the electrolyte to flow and diffuse freely throughout the entire casing. When the electrode assembly is in operation, electrolyte consumption can be replenished promptly, preventing localized drying, ensuring stable internal battery reactions, and improving charge-discharge performance.

[0009] In this invention, the cylinder has two first sidewalls and two second sidewalls, and the protrusions, recesses, and electrolyte storage areas are arranged in the following two ways:

[0010] The first method is as follows: the protrusion, the recess, and the electrolyte storage area are all set on the first side wall of the cylinder; specifically, the recess is a blind hole set on the first side wall, and the opening of the blind hole is flush with the outer surface of one of the second side walls, and the connecting pipe is set on the end face of the first side wall and the other second side wall that is flush with the outer surface; the electrolyte storage area is a hollow part, which is set on the surface of the first side wall near the inner cavity of the cylinder.

[0011] The second method is as follows: the protrusions and recesses are set on the second side wall of the cylinder. Specifically, a protrusion is set on the inner surface of one of the second side walls, and a blind hole is opened in the protrusion. The opening of the blind hole is flush with the outer surface of the second side wall. The area inside the cylinder corresponding to the height of the protrusion is the electrolyte storage area.

[0012] The protrusion is a connecting pipe disposed on the outer surface of another second sidewall.

[0013] Furthermore, in the second method described above, in order to better utilize the space inside the cylinder to divide the electrolyte storage area and the electrode assembly receiving area, the protrusion is closely attached to the inner surface of one of the first sidewalls. The cylinder also includes a partition parallel to the first sidewall. The partition is clamped between the protrusion and the other second sidewall, thereby dividing the inside of the cylinder into the electrolyte storage area and the electrode assembly receiving area. The partition has multiple hollow areas so that the electrolyte storage area and the electrode assembly receiving area are interconnected.

[0014] Furthermore, it also includes at least one support rib, each support rib being connected to the partition on one side and pressing against the first sidewall where the protrusion is in close contact with the other side. The presence of this support rib can, on the one hand, suppress the expansion of the electrode assembly, and on the other hand, increase the strength of the cylinder itself.

[0015] Furthermore, since the aforementioned cylinder is made of plastic, it can be injection molded to integrally form the recesses and protrusions on the cylinder. The processing is simple and ensures that the recesses and protrusions of each individual battery can be precisely matched, which is beneficial for the subsequent mass production and quality control of the battery pack.

[0016] Furthermore, the recesses and protrusions are connected via a heat-fusion process. During this process, the plastic material melts upon heating, and upon cooling and solidification, the materials of the connecting pipe and blind holes fuse together to form a single, integrated structure, creating a very strong bond between the recesses and protrusions. This connection method can withstand significant tensile, compressive, and shear forces, effectively preventing individual battery cells from loosening or separating during use and ensuring the structural stability of the battery pack. Simultaneously, heat-fusion connections have lower precision requirements; even with slight dimensional deviations in the recesses and protrusions during production, precise connections can still be achieved, greatly improving production efficiency.

[0017] A second aspect of the present invention provides a single battery cell, including an upper cover assembly, an electrode assembly, a lower cover assembly, and a cylindrical body as described in the first aspect; the upper cover assembly, the lower cover assembly, and the cylindrical body constitute the housing of the single battery cell.

[0018] Furthermore, the strength of the aforementioned 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 / discharge stage; and P2 is 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 cavity for the electrode components and electrolyte, and has a sealing function. Simultaneously, the strength of the sealed casing needs to meet the strength requirements of the casing during the formation stage and the normal charge / discharge stage; that is, the sealed casing must have a certain strength to ensure that it will not crack during the formation stage and the normal charge / discharge stage, despite changes in the internal environment of the battery, 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 cost of the entire battery pack or large-capacity battery.

[0019] Furthermore, the upper cover assembly includes an upper cover plate and a weak portion integrally disposed on the upper cover plate; the strength of the weak portion is less than the strength of the upper cover plate, and in the event of thermal runaway of a single cell, the thermal runaway flue gas breaks through the weak portion and is discharged.

[0020] The weak part of the present invention is integrally set with the upper cover plate, which has at least the following advantages:

[0021] 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.

[0022] 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.

[0023] 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.

[0024] A third aspect of the present invention provides a battery pack, including a housing and n individual batteries as described in the second aspect, wherein n is an integer greater than 1; the n individual batteries are installed in the housing in sequence by means of recesses and protrusions.

[0025] The enclosure strength meets the strength requirements of the shell during the thermal runaway stage. An explosion venting channel is provided between the enclosure and the cover assembly of each individual battery cell, and an explosion venting section is provided on the enclosure that communicates with the explosion venting channel. The explosion venting channel covers the weak part of each individual battery cell. When an individual battery cell experiences thermal runaway, the thermal runaway smoke breaks through the weak part, passes through the explosion venting channel, breaks through the explosion venting section, and is discharged from the enclosure.

[0026] The battery pack housing of this invention is a pressure-bearing housing, and its strength needs to meet the strength requirements of the shell during the thermal runaway stage; that is, the pressure-bearing housing is required to have good strength to ensure that during the thermal runaway stage, the pressure-bearing housing 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 battery pack after thermal runaway.

[0027] The beneficial effects of this invention are:

[0028] This invention features recesses and protrusions on the casing of individual battery cells. During battery pack assembly, the protrusion of one individual cell can be inserted into the recess of another and securely connected, improving the stability of the individual cells within the battery pack and making the entire battery pack structure more robust and durable. Simultaneously, the electrolyte storage area within the casing can store a significant amount of free electrolyte. Since electrolyte has a certain thermal conductivity, if the temperature rises during battery operation, the free electrolyte stored in the storage area can rapidly absorb heat through heat transfer, dispersing the absorbed heat throughout the individual battery casing and dissipating it through the casing surface. This effectively prevents battery overheating, reduces the risk of thermal runaway, precisely controls temperature, and maintains battery performance.

[0029] Furthermore, the electrolyte storage area and the electrode assembly housing area are interconnected, allowing the electrolyte to flow and diffuse freely throughout the entire casing. When the electrode assembly is in operation, electrolyte consumption can be replenished promptly, preventing localized drying, ensuring stable internal battery reactions, and improving charge-discharge performance. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of Example 1;

[0031] Figure 2 This is a schematic diagram of the structure of Example 2. Figure 1 ;

[0032] Figure 3 This is a schematic diagram of the structure of Example 2. Figure 2 ;

[0033] Figure 4 This is a schematic diagram of the structure of Example 3;

[0034] Figure 5 for Figure 4 A sectional view;

[0035] Figure 6 This is a schematic diagram of the structure of Example 4.

[0036] The attached figures are labeled as follows:

[0037] 1-Cylinder body, 11-First side wall, 12-Second side wall, 13-Electrolyte storage area, 2-Blind hole, 3-Connecting pipe, 4-Protrusion, 5-Partition plate, 6-Supporting rib, 100-Single cell, 200-Upper cover assembly, 201-Upper cover plate, 202-Weak part, 300-Lower cover assembly, 301-Lower cover plate, 302-Protrusion, 400-Box body, 500-Explosion relief channel, 600-Explosion relief part, 700-Heat exchange component. Detailed Implementation

[0038] 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.

[0039] 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.

[0040] 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.

[0041] Example 1

[0042] This embodiment provides a cylindrical body for a single battery, with both the upper and lower ends of the cylindrical body being open; the cylindrical body has an electrolyte storage area and an electrode assembly receiving area; a recess and a protrusion are provided on the side wall of the cylindrical body corresponding to the electrolyte storage area; wherein the recess is used for inserting the protrusion on the cylindrical body of another single battery and fixing it in place.

[0043] In this invention, the concave and convex portions of multiple individual cells are sequentially inserted, which can improve the stability of the individual cells within the battery pack, making the entire battery pack structure more compact and stable, effectively resisting interference under various operating conditions, and ensuring the continuous, efficient, and safe operation of the battery pack.

[0044] Meanwhile, the electrolyte storage area inside the casing can store a large amount of free electrolyte. Since electrolyte has a certain thermal conductivity, if the temperature rises during battery operation, the free electrolyte stored in the storage area can quickly absorb heat through heat transfer, dispersing the absorbed heat throughout the entire cell 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.

[0045] In order to reduce costs and battery weight, the casing of this embodiment is made of plastic and manufactured using injection molding. 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.

[0046] like Figure 1 As shown, in this embodiment, the cylinder 1 includes two first sidewalls 11 and two second sidewalls 12, wherein the first sidewall 11 is the small end face of the cylinder and the second sidewall 12 is the large end face of the cylinder; a blind hole 2 (i.e., a recess) is provided on the end face of the first sidewall 11 and one of the second sidewalls 12 that is flush with the outer surface; at least one connecting pipe 3 (i.e., a protrusion) is provided on the end face of the first sidewall 11 and the other second sidewall 12 that is flush with the outer surface; and a hollow portion is provided on the surface of the first sidewall near the inside of the cylinder 1, which serves as an electrolyte storage area 13.

[0047] Since the blind hole 2, the connecting pipe 3 and the electrolyte storage area 13 in this embodiment are all located on the first side wall 11, the first side wall 11 is required to be thicker. In order to save materials, when the cylinder is injection molded, the thickness of the other side wall is thinner than that of the first side wall 11 where the electrolyte storage area is located.

[0048] In some other embodiments, the protrusion may also be a solid column, which has higher strength and can withstand greater tensile and compressive forces.

[0049] In other words, the connecting pipe and the blind hole are integrally formed on the first side wall. The so-called hollow part can be a through hole with an L-shaped cross-section, or it can be a large pit directly set on the inner surface of the first side wall.

[0050] Since the cylinder body in this embodiment is made of plastic, it can be integrally molded using injection molding, resulting in a cylinder with blind holes and connecting pipes. During injection molding, the dimensions of the mold cavity can be precisely controlled, ensuring high dimensional accuracy of the blind holes and connecting pipes during molding and guaranteeing precise fit with other individual cells. Furthermore, because it is integrally molded, there is no issue of accumulated dimensional deviations due to the assembly process, ensuring the stability and consistency of the individual cell connections. This improves the overall performance and quality stability of the battery pack, reducing problems such as poor connections and abnormal battery operation caused by dimensional mismatches. Simultaneously, in adjacent individual cells, after the connecting pipe of one cell is inserted into the blind hole of another, the two can be fixedly connected by heat fusion. The plastic solidifies after heat fusion, fusing the two together to form a stable connection structure capable of withstanding significant mechanical stress. When the battery pack is subjected to external forces such as vibration, impact, or compression, it effectively prevents the connections between individual cells from loosening or detaching, ensuring the structural integrity and electrical connection stability of the battery pack under complex operating conditions. This, in turn, enhances the safety and reliability of the battery pack and extends its service life. In addition, the hot-melt connection method has lower precision requirements. Even with a certain degree of dimensional deviation, a good connection can be achieved through hot-melt, which reduces the precision control cost in the production process.

[0051] In some other embodiments, a metal cylinder may also be used, and therefore the blind hole and the connecting pipe are also made of metal. The blind hole and the connecting pipe can be connected by welding, interference fit, or other methods.

[0052] from Figure 1 and Figure 2 As can be seen from the figure, in this embodiment, there is at least one blind hole 2 and at least one connecting pipe 3 on the two parallel end faces of the first sidewall 11.

[0053] In some other embodiments, at least one blind hole 2 and at least one connecting pipe 3 may be provided on one end face of the first sidewall 11, and at least one connecting pipe 3 and at least one blind hole 2 may be provided on the other end face of the first sidewall 11.

[0054] In this embodiment, operators can easily distinguish the correspondence between blind holes and connecting pipes when assembling the battery pack, enabling them to quickly and accurately connect the individual battery cells. However, if both blind holes and connecting pipes are present on the same sidewall, operators need to be more careful in distinguishing which blind hole corresponds to which connecting pipe during assembly. A slight oversight can lead to mismatches, resulting in reduced assembly efficiency.

[0055] Example 2

[0056] The difference between this embodiment and Embodiment 1 is that, Figure 2 and 3As shown. Recesses and protrusions are provided on two second sidewalls 12; the specific structure is as follows: a protrusion 4 is provided on the inner surface of one of the second sidewalls 12, and a blind hole 2 is opened in the protrusion 4. The opening of the blind hole 2 is flush with the outer surface of the second sidewall 12; the area inside the cylinder corresponding to the height of the protrusion 4 is the electrolyte storage area 13; the protrusion is a connecting pipe 3 provided on the outer surface of the other second sidewall.

[0057] Bumps have the following two forms:

[0058] The first type is a block structure with multiple protrusions distributed along the height of the cylinder. Each protrusion has a blind hole.

[0059] The second type is a strip-shaped structure, usually one, which extends along the height direction of the cylinder, and multiple blind holes are opened on the protrusion along the height direction.

[0060] Preferably, in this embodiment, in order to better utilize the space inside the cylinder to divide the electrolyte storage area 13 and the electrode assembly receiving area, the protrusion 4 is closely attached to the inner surface of one of the first sidewalls 11. The cylinder 1 also includes a partition 5 parallel to the first sidewall 11. The partition 5 is sandwiched between the protrusion 4 and the other second sidewall 12 to divide the inside of the cylinder 1 into the electrolyte storage area and the electrode assembly receiving area. The partition 5 is provided with multiple hollow areas so that the electrolyte storage area and the electrode assembly receiving area are interconnected.

[0061] In addition to the partition, in this embodiment, at least one support rib 6 can also be provided. Each support rib 6 is connected to the partition 5 on one side and presses against the first sidewall 11 where the protrusion 4 is in close contact on the other side. The presence of the support rib can suppress the expansion of the electrode assembly on the one hand, and enhance the strength of the cylinder itself on the other hand.

[0062] Example 3

[0063] This embodiment provides a single-cell battery 100, such as Figure 4 and 5 As shown, it includes an upper cover assembly 200, an electrode assembly, a lower cover assembly 300, and a cylindrical body 1 as described in embodiments 1 and 2 above; the upper cover assembly 200, the lower cover assembly 300, and the cylindrical body 1 constitute a single battery casing.

[0064] To further reduce costs, the strength of each individual battery casing in this embodiment meets certain requirements. However, this embodiment does not require the casing to meet the strength requirements during the thermal runaway stage; it only needs to meet the strength requirements during the formation stage and normal charge / discharge processes. During the formation stage and normal charge / discharge processes, 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.

[0065] 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.

[0066] Under the premise of meeting the above strength requirements, in this embodiment, the thickness of the shell (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.

[0067] Preferably, in this embodiment, the upper cover assembly 200 differs from a conventional upper cover assembly in that the present invention integrally provides a weak part 202 on the upper cover plate 201 as a venting part for the single battery. When thermal runaway occurs inside the single battery and the internal pressure reaches a certain requirement, the thermal runaway smoke breaks through the weak part to form an opening and is discharged from the opening of the weak part 202.

[0068] Compared to the conventional separate arrangement of the explosion relief membrane and the top cover plate, the present invention integrates the top cover plate 201 and the weak part 202 into one piece, which has significant advantages.

[0069] 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, factors such as material aging and temperature changes can cause seal failure, leading to the loss 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 a high level of 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. Finally, 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 of the seals increases manufacturing uncertainty and the difficulty of quality control.

[0070] It should be noted that:

[0071] The strength of the aforementioned weak point is less than that of the rest of the top cover plate to ensure that it is the first to open in the event of thermal runaway. However, the strength of the weak point cannot be too low either; if it is, it may deform before thermal runaway occurs, thus affecting battery performance. Therefore, during the design phase, various stresses that the top cover plate will experience during normal battery operation must be comprehensively considered, 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.

[0072] The following three methods can be used to integrally mold the weak part 202 onto the upper cover plate 201:

[0073] The first method is: when the upper cover plate 201 is cast, a thinner area is intentionally formed on the upper cover plate as a weak part 202;

[0074] The second method is to form a thinner section in the upper cover plate 201 by stamping, which serves as the weak point 202.

[0075] The third method is to carve an annular groove on the upper cover plate 201 by machining, and the annular groove defines the weak part 202.

[0076] Preferably, in this embodiment, for ease of processing and manufacturing, the cylinder 1 and the lower cover assembly 300 can be integrally formed. The lower cover assembly 300 includes a lower cover plate and a plurality of protrusions 302 arranged in an array on the inner surface of the lower cover plate 301. The top of the protrusions 302 is used to support the electrode assembly, and the gap between the protrusions 302 serves as an electrolyte flow channel.

[0077] The regularly arranged protrusions 302 provide stable and evenly distributed support points for the electrode assembly, preventing deformation or damage caused by excessive local stress. Furthermore, the gaps between the protrusions serve as electrolyte flow channels, allowing the electrolyte to be evenly distributed around the electrode assembly, ensuring that all electrodes are in full contact with the electrolyte.

[0078] Example 4

[0079] Based on the single battery cell of Embodiment 3, this embodiment provides a battery pack, such as... Figure 6 As shown, it includes a housing 400 and 12 individual battery cells 100. In other embodiments, the number of individual battery cells 100 can be adjusted according to actual needs.

[0080] Twelve individual batteries 100 are sequentially installed inside the housing 200 via recesses and protrusions. A venting channel 500 is provided between the housing 400 and the cover assembly 200 of each individual battery 100. The housing 400 is provided with a venting section 600 that communicates with the venting channel 500 (this venting section can also be called an explosion-proof section, explosion-proof port, or explosion vent, etc., and is usually equipped with a pressure relief valve or explosion relief membrane, etc.). The venting channel covers the weak points 202 of each individual battery. In the event of thermal runaway of an individual battery, the thermal runaway fumes rupture through the weak points 202 of the individual battery, pass through the venting channel 500, and rupture through the venting section 600 to exit the housing.

[0081] In the initial stage of thermal runaway, the thermal runaway flue gas can be discharged in an orderly manner through the explosion venting channel 500 and break through the explosion venting section 600 on the enclosure, effectively preventing the thermal runaway flue gas from spreading inside the battery pack casing and failing to break through the explosion venting section 600 in time, thus preventing further deterioration of the thermal runaway situation.

[0082] In this embodiment, the outer casing of the battery pack serves as the core pressure-bearing casing. Simultaneously, plastic is used as the internal 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, significantly improving the overall safety of the battery pack, 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.

[0083] The strength of the pressure tank needs to meet the strength requirements of the casing during the thermal runaway stage; that is, the pressure tank needs to have good strength to ensure that it can form a robust thermal barrier during the thermal runaway stage. 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 the battery pack after thermal runaway.

[0084] 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.

[0085] To optimize the heat dissipation performance of the battery pack, this embodiment may further include a heat exchange component 700 for heat exchange at the polarity terminals. As a crucial connection between the battery's internal and external components, the polarity terminals 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 polarity terminals provides a relatively direct heat conduction path. Heat can be rapidly conducted from inside the battery to the polarity terminals, and then dissipated from the terminals to the external environment. Furthermore, since the polarity 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 polarity terminals, the temperature of these critical components can be reduced more effectively.

[0086] The heat exchange component 700 is a heat transfer tube; each polarity terminal of the individual cell 100 is provided with a through groove or through hole for installing the heat transfer tube; the heat transfer tube is fixed in the through groove or through hole of each individual cell's polarity terminal. Using the heat transfer tube on the polarity terminal, the heat generated inside the battery is conducted through the polarity terminal to the heat transfer tube, and then the heat transfer tube dissipates the heat, thus achieving heat dissipation for the battery.

[0087] The heat exchange component 700 can also be a heat exchange device, which is disposed on top of each individual cell 100. A polar terminal penetrates the heat exchange device, with at least a portion of its structure located within the heat exchange device's inner cavity and in direct contact with the heat exchange medium. Another portion of the polar terminal's structure is located outside the heat exchange device, serving as an electrical connection. The sidewall of the polar terminal is sealed to the heat exchange device. This direct heat exchange method places a portion of the polar terminal's structure directly within the heat exchange medium's flow cavity (the inner cavity of the heat exchange device), allowing direct contact between the polar terminal and the heat exchange medium, thus achieving heat exchange at the polar terminal. Compared to indirect heat exchange methods, this method has a shorter heat exchange path, and the heat exchange medium acts directly on the polar terminal, improving the utilization efficiency of the heat exchange medium and enhancing the battery's heat exchange efficiency.

Claims

1. A cylindrical body for a single-cell battery, characterized in that: Both the top and bottom ends of the cylinder are open; the cylinder contains an electrolyte storage area and an electrode assembly housing area. The side wall of the cylinder corresponding to the electrolyte storage area is provided with a recess and a protrusion; the recess is used for the protrusion on the cylinder of another single cell to be inserted and fixedly connected.

2. The cylindrical body for a single battery according to claim 1, characterized in that: The cylinder includes two first side walls and two second side walls; The recess is a blind hole provided on the first side wall, and the opening of the blind hole is flush with the outer surface of one of the second side walls. The connecting pipe is provided on the end face of the first side wall and the other second side wall that is flush with the outer surface. The electrolyte storage area is a hollow section, which is located on the surface of the first side wall near the inner cavity of the cylinder.

3. The cylindrical body for a single battery according to claim 1, characterized in that: The cylinder includes two first side walls and two second side walls; One of the second sidewalls has a protrusion on its inner surface, and a blind hole is formed in the protrusion. The opening of the blind hole is flush with the outer surface of the second sidewall. The area inside the cylinder corresponding to the height of the protrusion is the electrolyte storage area. The protrusion is a connecting pipe disposed on the outer surface of another second sidewall.

4. The casing for a single-cell battery according to claim 3, characterized in that: The protrusion is closely attached to the inner surface of one of the first sidewalls. The cylinder also includes a partition parallel to the first sidewall. The partition is clamped between the protrusion and the other second sidewall, thereby dividing the cylinder into an electrolyte storage area and an electrode assembly receiving area. The partition has multiple hollow areas so that the electrolyte storage area and the electrode assembly receiving area are interconnected.

5. The casing for a single battery according to claim 4, characterized in that: It also includes at least one support rib, each support rib having one side connected to the partition and the other side pressed against the first sidewall where the protrusion is in close contact.

6. The casing for a single-cell battery according to any one of claims 1 to 5, characterized in that: The cylinder is made of plastic.

7. A single-cell battery, characterized in that, It includes an upper cover assembly, an electrode assembly, a lower cover assembly, and a cylindrical body as described in any one of claims 1 to 6; the upper cover assembly, the lower cover assembly, and the cylindrical body constitute a single battery casing.

8. The single-cell battery according to claim 7, 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 charging and discharging stage of the battery; and P2 is the strength requirement of the casing during the thermal runaway stage.

9. The single-cell battery according to claim 8, characterized in that: The upper cover assembly includes an upper cover plate and a weak part integrally disposed on the upper cover plate; the strength of the weak part is less than the strength of the upper cover plate, and when a single cell experiences thermal runaway, the thermal runaway flue gas breaks through the weak part and is discharged.

10. A battery pack, comprising a housing and n individual batteries as described in claim 7, wherein n is an integer greater than 1; the n individual batteries are sequentially installed in the housing via recesses and protrusions. The enclosure strength meets the strength requirements of the shell during the thermal runaway stage. An explosion venting channel is provided between the enclosure and the cover assembly of each individual battery cell, and an explosion venting section is provided on the enclosure that communicates with the explosion venting channel. The explosion venting channel covers the weak part of each individual battery cell. When an individual battery cell experiences thermal runaway, the thermal runaway smoke breaks through the weak part, passes through the explosion venting channel, breaks through the explosion venting section, and is discharged from the enclosure.

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