Shell for single battery, single battery and battery pack

Abstract

The utility model belongs to the field of batteries, and particularly relates to a shell for a single battery, the single battery and a battery pack. The technical problem that the installation stability of each single battery in the existing battery pack is poor is solved. The shell is defined by an upper cover plate, a barrel and a lower cover plate. Each single battery comprises the shell; the battery pack comprises a plurality of single batteries; a concave part and a bulge are arranged on at least one of the opposite side walls of the upper cover plate and the lower cover plate; wherein the concave part is used for embedding a bulge on a cover plate corresponding to another single battery and is fixedly connected with the bulge; the stability of the single batteries in the box body is improved, and the structure of the whole battery pack is more stable and durable. A weak part is integrally arranged on the upper cover plate; the strength of the weak part is smaller than that of the upper cover plate, and when the single battery is in thermal runaway, thermal runaway flue gas bursts the weak part to be discharged. Due to the integrally-arranged weak part, the stability and reliability of the structure are greatly improved, and good explosion venting performance can be kept all the time.

Description

Technical Field

[0001] This utility model belongs to the field of batteries, specifically a casing 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] The purpose of this invention is to provide a casing for a single battery, a single battery, and a battery pack, overcoming the technical problem of poor installation stability of individual batteries within existing battery packs.

[0006] The first aspect of this utility model provides a housing for a single battery, which is characterized in that it is formed by an upper cover plate, a cylindrical body and a lower cover plate.

[0007] A recess and a protrusion are provided on the opposite sidewalls of at least one of the upper and lower cover plates; wherein the recess is used for embedding and fixing the protrusion on the corresponding cover plate of another single cell.

[0008] The top cover plate has an integrally formed weak section; the strength of the weak section is less than the strength of the top cover plate. When a single cell experiences thermal runaway, the thermal runaway smoke breaks through the weak section and is discharged.

[0009] This invention features recesses and protrusions on the cover plate. When assembling the battery pack, the protrusion of one individual battery can be inserted into the recess of another individual battery and fixedly connected, improving the stability of the individual battery within the casing and making the entire battery pack structure more robust and durable.

[0010] Meanwhile, this utility model sets the recesses and protrusions on the opposite sidewalls of the cover plate. The recesses and protrusions do not affect the dimensions of the individual battery cells in the height direction. This ensures both the stability of the connection within the battery pack and the overall compactness and space utilization efficiency of the battery pack.

[0011] Meanwhile, the present invention integrates a weak section as a venting section on the upper cover plate, which has at least the following advantages:

[0012] 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 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.

[0013] 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.

[0014] 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.

[0015] Furthermore, the recess is a blind hole opened on the first side wall of the lower cover plate; the protrusion is a connecting pipe provided on the outer wall of the second side wall of the lower cover plate; the connecting pipe is used to be embedded in the blind hole of another single battery cell and fixedly connected, and the first side wall of the lower cover plate and the second side wall of the lower cover plate are parallel to each other.

[0016] This invention employs a blind hole and connecting pipe connection, making the connection process simple and convenient. It allows for quick and accurate connection of individual battery cells, making the assembly of the entire battery pack more orderly and efficient. Once they are interlocked and fixed, a reliable connection is formed between adjacent battery cells. This ensures that the battery cells will not easily loosen or shift when subjected to vibration or impact, maintaining a stable electrical connection and structural state for a long time.

[0017] In addition, the blind holes and connectors do not affect the sealing performance of the individual battery casing.

[0018] Furthermore, a recessed area is created on the upper cover plate to form a weak point. Compared to some methods that create weak points by changing material composition or microstructure, creating a recessed area 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, shape, and area of ​​the recessed area, the opening of the weak point under a specific pressure can be accurately set, greatly improving the reliability of the explosion venting function.

[0019] Furthermore, through holes are made in the top cover plate along its width or length to form a weak section. When through holes are made in the top cover plate along its width or length to form a weak section, the flatness of the battery top cover plate can be maintained better than a weak section formed by a recessed area.

[0020] Furthermore, the casing is made of plastic; the recesses and protrusions are integral with the upper or lower cover plate; the recesses are used for the protrusions of another single battery cell to be inserted and are fixedly connected by heat fusion.

[0021] This invention can be manufactured using injection molding, where recesses and protrusions are integrally formed on the lower cover plate and / or the upper cover plate. The process is simple, and since the recesses, protrusions and cover plate are formed simultaneously, there are no dimensional deviations caused by subsequent assembly. The precision is high, ensuring that the recesses and protrusions of each individual battery cell can be precisely matched, which is beneficial for the mass production and quality control of the battery pack.

[0022] 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 recesses and protrusions 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 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 between the recesses and corresponding protrusions during production, precise connections can still be achieved, significantly improving production efficiency.

[0023] The second aspect of this utility model provides a single-cell battery, which is characterized in that it includes the aforementioned casing for the single-cell battery.

[0024] Furthermore, the shell strength is P, P1≤P≤P2; where P1 is the strength requirement of the shell during the formation stage and the normal charging and discharging stage of the battery; and P2 is the strength requirement of the shell during the thermal runaway stage.

[0025] The aforementioned single-cell battery casing is a sealed plastic casing that serves as a cavity for the electrode components and electrolyte, providing a sealing function. Simultaneously, the strength of the sealed casing must meet the strength requirements of the casing during the formation stage and the normal charge / discharge stage of the battery. That is, the sealed casing must possess sufficient strength to ensure that it will not crack under changes in the internal environment of the battery, such as temperature and pressure, during the formation stage and normal charge / discharge stage. Compared to existing finished plastic-cased single-cell batteries, this single-cell battery has a lower cost, thereby reducing the overall cost of the battery pack.

[0026] The third aspect of this utility model provides a battery pack, including a pressure-bearing housing and n individual batteries arranged in the pressure-bearing housing, wherein n is an integer greater than 1.

[0027] In adjacent individual cells, the protrusion of one individual cell is inserted into the recess of another individual cell and fixedly connected; a venting channel is formed between the weakest part of each individual cell and the pressure-bearing box.

[0028] The pressure tank has the strength required for the shell during thermal runaway, and the pressure tank is equipped with a venting section corresponding to the venting channel. When a single cell experiences thermal runaway, the thermal runaway flue gas breaks through the weak part, passes through the venting channel, and then breaks through the venting section to exit the pressure tank.

[0029] In the initial stage of thermal runaway, the thermal runaway flue gas can be discharged in an orderly manner through the explosion relief channel, effectively preventing it from spreading to the pressure tank of the battery pack, thereby preventing further deterioration of the thermal runaway situation.

[0030] The outer casing of this battery pack is a pressure-bearing casing, and its strength must meet the requirements for shell strength during thermal runaway. That is, the pressure-bearing casing must have good strength to ensure that during thermal runaway, it can form a robust barrier, effectively isolating high-temperature flames and harmful gases, preventing the spread of thermal runaway, and improving the safety of the battery pack after thermal runaway. Inside the pressure-bearing casing, adjacent individual cells are connected by recesses and protrusions, providing reliable tension and support for adjacent individual cells, further improving the stability of the individual cells within the pressure-bearing casing, and making the entire battery pack structure more robust and durable.

[0031] Furthermore, the top plate of the pressure tank has clearance holes corresponding to the polarity terminals of each individual battery; the polarity terminals of each individual battery extend 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 individual battery casing.

[0032] Furthermore, the aforementioned battery pack also includes a heat exchange component that exchanges heat with the polarity terminals.

[0033] During battery pack operation, heat can easily accumulate at the polarized terminals due to current conduction. Heat exchange components can promptly remove this heat, ensuring the polarized 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.

[0034] The beneficial effects of this utility model are:

[0035] This invention features mating recesses and protrusions on the individual battery cover plates (upper and / or lower cover plates). During battery pack assembly, the protrusion of one individual battery can be inserted into the recess of another, securing them together and improving the stability of the individual batteries within the pack, thus making the entire battery pack structure more robust and durable. Furthermore, by placing the recesses and protrusions on opposite sidewalls of the cover plates, this invention does not affect the vertical dimensions of the individual batteries, ensuring both connection stability and overall compactness and space utilization efficiency within the battery pack.

[0036] This invention also incorporates a weak section on the upper cover plate as a single-cell explosion venting section. Compared with existing structures that use an explosion venting membrane as the explosion venting section, this invention has the advantages of high structural stability, good sealing performance, and low manufacturing cost.

[0037] Specifically, existing explosion-proof membranes are typically attached to the battery cover by adhesive or other means. 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.

[0038] Achieving an absolute seal at the junction of the existing explosion-proof membrane and the top cover plate presents numerous challenges and requires significant costs. In contrast, this invention features a seamlessly integrated weak point that connects to 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 costs, and improves product consistency and quality stability. Attached Figure Description

[0039] Figure 1 This is a schematic diagram of the structure of the first type of single cell in Example 1 from a first-view perspective;

[0040] Figure 2 This is a schematic diagram of the structure of the first type of single cell in Example 1 from a second perspective;

[0041] Figure 3 This is a schematic diagram of the second type of single-cell battery in Example 1 from a first-view perspective;

[0042] Figure 4 This is a schematic diagram of the second type of single-cell battery in Example 1 from a second perspective;

[0043] Figure 5 This is a partial cross-sectional view of the single battery casing in Example 1;

[0044] Figure 6 This is a schematic diagram of a partial structure of the single battery casing in Example 1;

[0045] Figure 7 This is a schematic diagram of the structure of the top cover plate of a single battery in Example 3;

[0046] Figure 8 This is a schematic diagram of the structure of the top cover plate of the single cell in Example 4;

[0047] Figure 9 This is a schematic diagram of the structure of a single cell in Example 4;

[0048] Figure 10 This is a schematic diagram of the battery pack structure in Example 5;

[0049] Figure 11 This is a schematic diagram of the exploded structure of a battery pack in Example 5;

[0050] Figure 12 This is a schematic diagram of a partial explosion structure of a battery pack in Example 5;

[0051] Figure 13 This is a schematic diagram of a partial explosion structure of the second type of battery pack in Example 5;

[0052] Figure 14 This is a schematic diagram of the exploded structure of the third type of battery pack in Example 5;

[0053] Figure 15 This is a schematic diagram of a partial explosion structure of the third type of battery pack in Example 5;

[0054] Figure 16 This is a schematic diagram of a partial explosion structure of the fourth type of battery pack in Example 5;

[0055] Figure 17 This is a schematic diagram of the exploded structure of the fifth type of battery pack in Example 5;

[0056] Figure 18 This is a schematic diagram of the fifth type of battery pack in Example 5.

[0057] The attached figures are labeled as follows:

[0058] 1. Top cover plate; 11. Polar terminal; 2. Cylinder body; 3. Bottom cover plate; 31. Blind hole; 32. Bottom of blind hole; 33. Connecting pipe; 6. Recess; 7. Protrusion; 8. Single cell; 9. Pressure tank; 10. Heat exchange component; 12. Boss; 13. Explosion relief part; 14. Second channel; 15. Clearance hole; 42. Through groove; 45. Groove; 46. Through hole. Detailed Implementation

[0059] To make the above-mentioned objectives, features, and advantages of this utility model more apparent and understandable, the specific embodiments of this utility model will be described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort should fall within the protection scope of this utility model.

[0060] Many specific details are set forth in the following description in order to provide a full understanding of the present invention. However, the present invention may also be implemented in other ways different from those described herein. Those skilled in the art can make similar extensions without departing from the spirit of the present invention. Therefore, the present invention is not limited to the specific embodiments disclosed below.

[0061] In the description of this utility model, it should be noted that the terms "top," "bottom," etc., indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this utility model 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 this utility model. 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.

[0062] Example 1

[0063] like Figure 1 and Figure 2 The diagram shown is a structural schematic of the single battery 8 in this embodiment, which includes a housing. The housing is formed by an upper cover plate 1, a cylindrical body 2, and a lower cover plate 3.

[0064] To reduce costs and battery weight, this embodiment uses a plastic casing. The lower cover plate 3 and the cylinder 2 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. Furthermore, the injection-molded integral part ensures uniform material distribution and tight bonding, resulting in a stronger connection between the battery lower cover plate 3 and the cylinder 2, and higher overall structural strength. Additionally, reinforcing ribs can be integrally molded on the cylinder 2, effectively increasing its resistance to bending, compression, and torsion.

[0065] In this embodiment, the upper cover plate 1 and the cylinder 2 can be sealed together by heat fusion or welding. This ensures a continuous, uniform, and tight connection between the upper cover plate 1 and the cylinder 2, resulting in extremely high stability. External water, dust, and other impurities cannot enter the battery, thus providing excellent protection for the electrode components and ensuring the battery's performance and lifespan.

[0066] It should be noted that the plastic material selected in this utility model should have the following properties:

[0067] First, it must have sufficient strength to ensure the stability of the battery structure;

[0068] Second, it has chemical corrosion resistance and can resist the corrosion of electrolytes;

[0069] 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.

[0070] 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.

[0071] The plastic material used can be the same material used in existing plastic-cased single-cell batteries 8, or the plastic material disclosed in Chinese patents CN106543551A and CN106977894A.

[0072] For ease of description, in this embodiment, the width direction of the casing of the single battery 8 is defined as the x-direction, the length direction as the y-direction, and the height direction as the z-direction.

[0073] like Figure 1 and Figure 2 As shown, in this embodiment, a recess 6 and a protrusion 7 are provided on the opposite sidewall of the lower cover plate 3; wherein the recess 6 is used for inserting the protrusion 7 on the lower cover plate 3 of another single battery cell 8 and fixing it in place. Connecting multiple single batteries 8 in a corresponding manner can improve the stability of the single batteries 8 in the battery pack, making the structure of the entire battery pack more compact and stable, effectively resisting interference under various operating conditions, and ensuring the continuous, efficient and safe operation of the battery pack.

[0074] In some other embodiments, a recess 6 and a protrusion 7 may be provided on the opposite sidewall of the upper cover plate 1; wherein the recess 6 is used for the protrusion 7 on the upper cover plate 1 of another single cell 8 to be inserted and fixedly connected.

[0075] In this embodiment, as Figure 3 and Figure 4 As shown, recesses 6 and protrusions 7 can also be provided on the opposite sidewalls of the lower cover plate 3 and the upper cover plate 1; wherein the recesses 6 are used for the protrusions 7 on the corresponding cover plate of another single battery 8 to be inserted and fixedly connected. By connecting the single batteries 8 at different positions, the stability of the single batteries 8 in the box is further enhanced, making the structure of the entire battery pack more stable and durable.

[0076] This invention places the recess 6 and the protrusion 7 on the opposite sidewalls of the cover plate (upper cover plate 1 and / or lower cover plate 3), ensuring that the recess 6 and the protrusion 7 do not generate additional dimensional increments in the height direction of the individual battery cell 8. For battery packs, especially in applications with stringent space requirements, this connection structure that does not increase the height dimension is particularly important. It allows the battery pack to accommodate more individual batteries 8 within a limited space, or, while meeting the same battery capacity requirements, makes the overall battery pack more compact and lightweight, facilitating device portability, installation, and layout optimization.

[0077] Since the shell in this embodiment is made of plastic, the upper cover plate 1 or lower cover plate 3 with the recess 6 and protrusion 7 can be integrally molded using injection molding. During injection molding, the dimensions of the mold cavity can be precisely controlled, ensuring high dimensional accuracy of the recess 6 and protrusion 7 during molding, guaranteeing precise fit with other individual battery cells 8. Furthermore, because it is integrally molded, there is no problem of accumulated dimensional deviations due to the assembly process, ensuring the stability and consistency of the connection between individual battery cells 8. This is beneficial for improving the overall performance and quality stability of the battery pack, reducing problems such as poor connection and abnormal battery operation caused by dimensional mismatch. Simultaneously, in adjacent individual battery cells 8, after the protrusion 7 of one individual battery cell 8 is inserted into the recess 6 of another individual battery cell 8, the two can be fixedly connected by heat fusion. After the plastic cools and solidifies after heat fusion, the two become integrated, forming a stable connection structure capable of withstanding significant mechanical stress. For example, when the battery pack is subjected to external forces such as vibration, impact, or compression, it effectively prevents the connection between individual battery cells 8 from loosening or detaching, ensuring the structural integrity and electrical connection stability of the battery pack under complex operating conditions, thereby improving the safety and reliability of the battery pack and extending 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.

[0078] In some other embodiments, a metal housing and recesses 6 and protrusions 7 may also be used, and the recesses 6 and protrusions 7 may be connected by welding, interference fit or other means.

[0079] from Figure 1 and Figure 2As can be seen from the image, in this embodiment, the recess 6 and the protrusion 7 are respectively provided on the first sidewall and the second sidewall of the lower cover plate 3, which are parallel to each other. In addition, two recesses 6 can be provided on the first sidewall, and two protrusions 7 can be provided on the second sidewall.

[0080] In some other embodiments, a recess 6 and a protrusion 7 may be provided on the first sidewall, and a corresponding protrusion 7 and a recess 6 may be provided on the second sidewall.

[0081] In this embodiment, when assembling the battery pack, the operator can easily distinguish the correspondence between the recesses 6 and the protrusions 7, and can quickly and accurately connect the individual battery cells 8. However, if there are both recesses 6 and protrusions 7 on the same side wall, the operator needs to be more careful in distinguishing which recess 6 corresponds to which protrusion 7 during assembly. If the operator is not careful, a mismatch may occur, resulting in reduced assembly efficiency.

[0082] It should be noted that:

[0083] The first and second sidewalls described above are parallel to each other and can both be parallel to the xz plane. When parallel to the xz plane, both the protrusion 7 and the recess 6 extend along the y direction. Alternatively, both the first and second sidewalls can be parallel to the yz plane. When parallel to the yz plane, both the protrusion 7 and the recess 6 extend along the x direction.

[0084] The following example mainly focuses on the first and second sidewalls being parallel to the yz plane.

[0085] from Figure 5 As can be seen, in this embodiment, the recess 6 is a blind hole 31 opened on the first side wall of the lower cover plate 3, that is, the opening end of the blind hole 31 is located on the first side wall of the lower cover plate 3. The protrusion 7 is a connecting tube 33 provided on the outer wall of the second side wall of the lower cover plate 3; the connecting tube 33 is used to be embedded in the blind hole 31 of another single battery 8 and fixedly connected.

[0086] In some other embodiments, the recess 6 may also be a groove 45 formed on the first sidewall of the lower cover plate 3.

[0087] In some other embodiments, the protrusion 7 may also be a solid column, which has higher strength and can withstand greater tensile and compressive forces.

[0088] from Figure 6It can also be seen that this embodiment has multiple protrusions 12 arranged in an array on the inner surface of the lower cover plate 3. The tops of the protrusions 12 are used to support the electrode assembly, and the gaps between the protrusions 12 serve as electrolyte flow channels. The multiple protrusions 12 can be arranged in a rectangular array or a ring array, etc. The regularly arranged multiple protrusions 12 can provide stable and uniformly distributed support points for the electrode assembly, avoiding the deformation or damage of the electrode assembly due to excessive local stress. At the same time, using the gaps between the protrusions 12 as electrolyte flow channels allows the electrolyte to be evenly distributed around the electrode assembly, ensuring that the electrodes in each part can fully contact the electrolyte.

[0089] Furthermore, during battery operation, if the temperature rises, the electrolyte stored in the electrolyte flow channels can rapidly absorb heat through heat transfer, dispersing the absorbed heat throughout the 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.

[0090] from Figure 5 As can be seen, in this embodiment, both the blind hole 31 and the connecting pipe 33 are hollow structures. After being constructed into a battery pack, under the action of external force, the bottom end 32 of the blind hole and the second side wall area of ​​the lower cover plate 3 enclosed by the connecting pipe 33 will be hollow. Figure 5 The area shown in the middle circle (a) can be opened, immediately connecting the inner cavities of all blind holes 31 and the connecting pipe 33, and further connecting them with the electrolyte areas of all individual battery cells 8, achieving electrolyte sharing. In this way, the differences that may have existed between individual battery cells 8 can be effectively improved, ensuring the consistency of each individual battery cell 8 during charging and discharging, extending the overall service life, and improving battery performance.

[0091] The above-mentioned external force generally refers to using appropriate tools to apply a certain force to the bottom end 32 of the blind hole and the second side wall area of ​​the lower cover plate 3 enclosed by the connecting pipe 33, causing it to break and form an opening.

[0092] In addition, such as Figure 1 and Figure 2 As shown, in this embodiment, a through groove 42 can also be formed on the upper surface of the upper cover plate 1, and the area of ​​the upper cover plate 1 corresponding to the bottom of the through groove 42 is regarded as a weak part. When thermal runaway occurs inside the single cell 8 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.

[0093] from Figure 1 As can be seen from the image, in this embodiment, the through groove 42 penetrates the upper cover plate 1 along the x direction and is located between the two polarity terminals 11 of the upper cover plate 1.

[0094] From a thermal management perspective, the polar terminals 11 are usually the concentrated areas of heat generation in the battery. By placing the weak points near the two polar terminals 11, the heat generated by thermal runaway can be dissipated in a timely manner, effectively alleviating local high temperatures and optimizing the internal heat distribution of the battery.

[0095] In terms of structural layout, this arrangement makes the battery top cover 1 more compact and rational. Compared to placing the weakest part in other locations, it reduces interference with other functional areas of the battery, achieving a more efficient layout within a limited space.

[0096] In some other embodiments, the through slot 42 can also extend through the upper cover plate 1 along the length of the upper cover plate 1, avoiding the location of the polarity terminal 11.

[0097] The depth and width of the through groove 42 can be set according to specific needs to ensure that the area of ​​the upper cover plate 1 where the bottom of the through groove 42 is located can be opened under the set pressure.

[0098] However, it is important to note that the depth and width of the through-slot 42 should not be excessive. If the dimensions exceed a reasonable range, the through-slot 42 may deform due to insufficient strength when the battery has not experienced thermal runaway, thereby affecting battery performance. Therefore, during the design phase, it is necessary to comprehensively consider the various stresses that the top cover 1 will bear during normal battery operation, including internal pressure and external vibration. By rationally planning the corresponding dimensions of the through-slot 42, while ensuring the structural stability of the top cover 1 under normal operating conditions, it is also ensured that the through-slot 42 can reliably perform its explosion-venting function in the event of thermal runaway.

[0099] In this embodiment, the top cover 1 is made of plastic and can be integrally molded using injection molding, forming a top cover 1 with recesses 6, protrusions 7, and through grooves 42. The integrally molded through grooves 42 also avoids additional splicing gaps, ensuring the overall sealing of the top cover 1 and effectively preventing the intrusion of external impurities. In addition, the injection molding process is low-cost and highly efficient, reducing processing steps and production costs, resulting in significant economic benefits in large-scale production.

[0100] Example 2

[0101] Unlike the embodiments described above, this embodiment, in order to further reduce costs, requires that the strength of each individual battery casing 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. (Correspondingly, the strength of the weak points provided on it should also 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.

[0102] 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.

[0103] Under the premise of meeting the above strength requirements, in this embodiment, the thickness of the shell (cylinder 2, upper cover plate 1, and lower cover plate 3) is h, where h is less than h0, and h0 is the thickness of the plastic shell of a traditional single-cell battery 8; the thickness of the plastic shell of a traditional single-cell battery 8 is typically 5-8 mm. In this embodiment, the thickness of the shell can be between 1-4 mm. By reducing the thickness of the shell of a traditional single-cell battery 8 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.

[0104] Example 3

[0105] Unlike Embodiments 1 and 2, this embodiment has a groove 45 formed on the lower surface of the upper cover plate 1, and the area of ​​the upper cover plate 1 corresponding to the bottom of the groove 45 is a weak part.

[0106] Specifically, such as Figure 7 As shown, in this embodiment, the groove 45 extends along the x-direction. Similar to Embodiment 1, the groove 45 is located between the two polar terminals 11.

[0107] The depth and width of the groove 45 can be set according to specific needs to ensure that the area of ​​the upper cover plate 1 where the bottom of the groove 45 is located can be opened under the set pressure.

[0108] However, it is also important to note that the depth and width of the groove 45 should not be too large. If the dimensions exceed a reasonable range, the groove 45 may deform due to insufficient strength when the battery has not experienced thermal runaway, thereby affecting battery performance. Therefore, during the design phase, it is necessary to comprehensively consider the various stresses that the top cover 1 will bear during normal battery operation, including internal pressure and external vibration. By rationally planning the corresponding dimensions of the groove 45, while ensuring the structural stability of the top cover 1 under normal operating conditions, it is also necessary to ensure that the groove 45 can reliably perform its explosion-proof function in the event of thermal runaway.

[0109] Compared to the example of opening a through groove 42 on the upper surface of the upper cover plate 1 in Example 1, this example can better maintain the flatness of the battery upper cover plate 1.

[0110] In addition, during normal operation of the single cell 8, the inner cavity of the groove 45 can serve as a gas storage cavity, where the gas generated inside the single cell 8 can be stored, thus reducing the degree of bulging of the single cell 8 casing.

[0111] Example 4

[0112] Unlike the above embodiments, this embodiment has a through hole 46 in the upper cover plate 1 along its width direction, forming a weak part.

[0113] Specifically, such as Figure 8 and Figure 9 As shown, this embodiment also uses a plastic cover plate 1, which can be integrally molded with a through hole 46 using an injection molding process.

[0114] As can be seen from the figure, in this embodiment, the through hole 46 extends through the upper cover plate 1 along the width direction of the upper cover plate 1 and is located between the two polarity terminals 11 of the upper cover plate 1.

[0115] In some other embodiments, a through hole 46 along the length of the upper cover plate 1 may be formed to create a weak point.

[0116] The cross-sectional shape and size of the through hole 46 can be set according to specific requirements to ensure that the area of ​​the upper cover plate 1 where the through hole 46 is located can be opened under the set pressure.

[0117] However, it is also important to note that the through hole 46 should not be too large. If it exceeds a reasonable range, the through hole 46 may deform due to insufficient strength when the battery has not experienced thermal runaway, thus affecting battery performance. Therefore, during the design phase, it is necessary to comprehensively consider the various stresses that the top cover 1 will bear during normal battery operation, including internal pressure and external vibration. By rationally planning the corresponding dimensions of the through hole 46, while ensuring the structural stability of the top cover 1 under normal operating conditions, it is also necessary to ensure that the through hole 46 can reliably perform its explosion-venting function in the event of thermal runaway.

[0118] Compared to the weak point in Embodiment 1, this embodiment can also better maintain the flatness of the battery cover plate 1.

[0119] Example 5

[0120] This embodiment is a battery pack, including a pressure-bearing housing 9 and 12 individual battery cells 8 as described in the above embodiment, arranged within the pressure-bearing housing 9. In other embodiments, the number of individual battery cells 8 can be adjusted according to actual needs.

[0121] Its structure is as follows Figures 10 to 15 As shown, Figure 11 and Figure 12 To adopt Figure 1 Taking the single cell 8 shown as an example, Figure 13 To adopt Figure 3 Taking the single cell 8 shown as an example, Figure 14 and Figure 15 To adopt Figure 7 Taking the single cell 8 corresponding to the upper cover plate 1 as an example, Figure 16 To adopt Figure 9 The single cell shown is 8 as an example.

[0122] In adjacent single cells 8, the connector 33 of one single cell 8 is embedded in the blind hole 31 corresponding to the connector 33 of the other single cell 8, and is connected by heat fusion.

[0123] Figures 11 to 13 In the middle, the weak part is the through groove 42. The through grooves 42 of each individual battery 8 are connected (or spliced) to form an explosion relief channel. This explosion relief channel is located between the weak part of each individual battery 8 and the pressure-bearing box 9. Alternatively, a channel can be set on the pressure-bearing box 9. This channel covers the through grooves 42 of each individual battery 8 and forms an explosion relief channel with a larger cavity with the through grooves 42 of the individual battery 8.

[0124] Figure 14 and Figure 15 In the middle, the weak part is the groove 45 opened on the lower surface of the upper cover plate 1. A second channel 14 needs to be set on the pressure box 9. The second channel 14 covers the weak part of each individual battery 8 (the area of ​​the upper cover plate 1 corresponding to the bottom of the groove 45) and forms a venting channel between it and the weak part of the individual battery 8.

[0125] Figure 16 In the middle, the weak part is the through hole 46 opened on the upper cover plate 1. The through holes 46 of each individual battery 8 are connected to form an explosion relief channel. This explosion relief channel is also located between the weak part (the bottom of the through hole 46) and the pressure box 9.

[0126] like Figure 10As shown, the pressure chamber 9 is provided with an explosion relief part 13 corresponding to the explosion relief channel (the explosion relief part 13 here can also be called an explosion-proof part, explosion-proof port or explosion relief port, etc., and is usually provided with a pressure relief valve or explosion relief membrane, etc.). When the single cell 8 thermally runs away, the thermal runaway smoke breaks through the weak part, passes through the explosion relief channel, breaks through the explosion relief part 13 and is discharged from the pressure chamber 9.

[0127] In the initial stage of thermal runaway, the thermal runaway flue gas can be discharged in an orderly manner through the explosion relief channel, effectively preventing it from spreading to the battery pack casing and thus preventing further deterioration of the thermal runaway situation.

[0128] The strength of the pressure-bearing housing 9 needs to meet the strength requirements of the casing during thermal runaway, meaning that the pressure-bearing housing 9 must have good strength. This design not only effectively resists the high-pressure impact during thermal runaway with the reinforced outer casing, greatly improving the overall safety of the battery pack; especially when plastic material is used as the casing of the internal individual cells 8, the pressure-bearing housing 9 can form a robust thermal barrier. Even in the extreme case where the casing of the individual cell 8 melts, it can effectively isolate high-temperature flames and harmful gases, preventing the spread of thermal runaway and improving the safety of the battery pack after thermal runaway. In addition, when plastic material is used as the casing of the internal individual cells 8, an anti-seepage membrane can be provided between each individual cell 8 and the pressure-bearing housing 9 to prevent the electrolyte inside each individual cell 8 from seeping out.

[0129] Compared to other materials, the metal pressure tank 9 is more reliable in emergency situations such as thermal runaway. It can withstand greater impact and destructive forces, reducing the likelihood of accidents and protecting personnel and surrounding equipment. In this embodiment, the pressure tank 9 does not directly contact the electrolyte, so an iron, steel, or stainless steel shell can be used. An iron shell offers advantages in strength and cost, making it a viable option in scenarios where cost is a primary concern and strength requirements are not particularly stringent. A steel shell provides relatively high strength, offering more reliable protection for the battery and is suitable for applications with high safety and structural strength requirements. A stainless steel shell not only possesses good strength properties but also excellent corrosion resistance, making it perform exceptionally well in battery applications that may face humid or corrosive environments. This effectively extends battery life and ensures stable operation in complex environments.

[0130] like Figure 17 and Figure 18 As shown, to adopt Figure 1 Taking the single battery 8 shown as an example, in this embodiment, a clearance hole 15 is provided on the top plate of the pressure-bearing box 9 corresponding to the polarity terminal 11 of each single battery 8; the polarity terminal 11 of each single battery 8 extends out of the clearance hole 15; the top plate area of ​​the pressure-bearing box 9 corresponding to the clearance hole 15 is fixedly sealed with the housing of the single battery 8.

[0131] To optimize the heat dissipation performance of the battery pack, this embodiment adds a heat exchange component 10 to the battery pack to exchange heat with the polarity terminal 11. The polarity terminal 11 is a key component connecting the battery's internal and external components; during charging and discharging, current flows through the polarity terminal 11 into and out of the battery. When heat is generated inside the battery, heat dissipation through the polarity terminal 11 provides a relatively direct heat conduction path. Heat can be quickly conducted from inside the battery to the polarity terminal 11, and then dissipated from the polarity terminal 11 to the external environment. Furthermore, since the polarity terminal 11 is 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 terminal 11, the temperature of these key components can be reduced more effectively.

[0132] The heat exchange component 10 can be a heat transfer tube; each polarity terminal 11 of the individual cell 8 is provided with a through groove 42 or through hole for installing the heat transfer tube; the heat transfer tube is fixed in the through groove 42 or through hole of each polarity terminal 11 of the individual cell 8. By using the heat transfer tube on the polarity terminal 11, the heat generated inside the battery is conducted to the heat transfer tube through the polarity terminal 11, and then the heat transfer tube dissipates the heat to achieve heat dissipation of the battery.

[0133] The heat exchange component 10 can also be a heat exchange device, which is disposed on top of each individual battery cell 8. A polar terminal 11 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 11 is located outside the heat exchange device, serving as an electrical connection. The sidewall of the polar terminal 11 is sealed to the heat exchange device. By employing a direct heat exchange method, a portion of the polar terminal 11 is directly placed within the heat exchange medium flow cavity (the inner cavity of the heat exchange device), allowing direct contact between the polar terminal 11 and the heat exchange medium. This achieves heat exchange for the polar terminal 11, resulting in a shorter heat exchange path. The heat exchange medium directly acts on the polar terminal 11, improving the utilization efficiency of the heat exchange medium and enhancing the battery's heat exchange efficiency.

[0134] In this embodiment, an insulating sealant layer can also be provided between each individual battery cell 8 and between each individual battery cell 8 and the pressure-bearing housing 9. The insulating sealant layer is mainly laid in the space between each individual battery cell 8 and the pressure-bearing housing 9, and the heat exchange components 10 inside the pressure-bearing housing 9 are all located within the insulating sealant layer; when there are gaps between each individual battery cell 8, the insulating sealant liquid can also seep into the gaps to form an insulating sealant layer. It should be noted that no insulating sealant layer is provided in the explosion relief channel.

[0135] In this embodiment, the insulating sealant layer has at least the following advantages:

[0136] 1. Prevent condensation;

[0137] During long-term use, due to the temperature difference between the inside and outside of the heat exchange component 10, 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 10, when condensation forms on the surface of the heat exchange component 10, the battery short circuit can be prevented under the protection of the insulating sealant layer.

[0138] II. Further improve the stability of each individual battery cell 8 within the pressure-bearing housing 9;

[0139] The insulating sealant penetrates into the gaps between individual cells 8 and between individual cells 8 and the pressure tank 9, which can further improve the stability of individual cells 8 within the pressure tank 9.

[0140] use Figure 17 and Figure 18 In the structure shown, an insulating sealant layer can also be laid on the top plate of the pressure tank 9, and the heat exchange component 10 is located inside the insulating sealant layer. When condensation occurs on the surface of the heat exchange component 10, the battery short circuit can be prevented under the protection of the insulating sealant layer.

Claims

1. A case for a single battery, characterized by: The shell is enclosed by the upper cover plate, the cylinder and the lower cover plate; The recess is used for embedding the protrusion on the corresponding cover plate of another single battery, and fixedly connected. The upper cover plate is integrally provided with a weak part; the strength of the weak part is less than that of the upper cover plate, and the thermal runaway flue gas is discharged by breaking the weak part when the single battery is in thermal runaway.

2. The case for a single cell according to claim 1, characterized by: The recess is a blind hole opened in the first side wall of the lower cover plate; the protrusion is a butt joint pipe arranged on the outer wall of the second side wall of the lower cover plate; the butt joint pipe is used for embedding in the blind hole of another single battery, and fixedly connected; the first side wall of the lower cover plate and the second side wall of the lower cover plate are parallel to each other.

3. The case for a single cell according to claim 1 or 2, characterized by: A recessed area is arranged on the upper cover plate to form a weak part.

4. The case for a single cell according to claim 1 or 2, characterized by: A through hole is opened on the upper cover plate along the width or length direction of the upper cover plate to form a weak part.

5. The case for a single cell according to claim 1, characterized by: The shell is made of plastic material; the recess and the protrusion are integrated with the upper cover plate or the lower cover plate; the recess is used for embedding the protrusion of another single battery, and fixedly connected by hot melting.

6. A single cell, characterized by: The shell includes the shell for single battery according to any one of claims 1 to 5.

7. The cell according to claim 6, wherein: The strength of the shell is P, P1≤P≤P2; wherein P1 is the strength requirement of the shell in the formation stage and the normal charging and discharging stage of the battery; P2 is the strength requirement of the shell in the thermal runaway stage.

8. A battery pack, characterized by: The shell includes a pressure-bearing box body and n single batteries according to claim 6 or 7 arranged in the pressure-bearing box body, wherein n is an integer greater than 1; In adjacent single batteries, the protrusion of one single battery is inserted into the recess of another single battery, and fixedly connected; the weak part of each single battery and the pressure-bearing box body form a blast venting channel; The strength of the pressure-bearing box body meets the strength requirement of the shell in the thermal runaway stage, and the pressure-bearing box body is provided with a blast venting part corresponding to the blast venting channel; when the single battery is in thermal runaway, the thermal runaway flue gas breaks the weak part, passes through the blast venting channel, breaks the blast venting part and is discharged from the pressure-bearing box body.

9. The battery pack of claim 8, wherein: The top plate of the pressure-bearing box body is provided with a avoiding hole corresponding to the polarity terminal of each single battery; the polarity terminal of each single battery extends out of the avoiding hole; the area of the top plate of the pressure-bearing box body corresponding to the avoiding hole is fixedly sealed with the shell of the single battery.

10. The battery pack of claim 8 or 9, wherein: The heat exchange member is further provided, and the heat exchange member exchanges heat with the polarity terminal.

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