Battery pack

Abstract

The utility model belongs to the field of batteries, and particularly relates to a battery pack. The technical problem that when thermal runaway happens to an existing battery pack, safety is low is solved. The battery pack comprises a pressure-bearing box body and n semi-finished single batteries arranged in the pressure-bearing box body, and each semi-finished single battery comprises a sealing shell and an electrode assembly located in the sealing shell; the sealing shell is a plastic shell, the strength of the sealing shell is P, and P is larger than or equal to P1 and smaller than or equal to P2; wherein P1 is the strength requirement of the formation stage and the normal charging and discharging stage of the battery on the shell; p2 is the strength requirement on the shell in the thermal runaway stage; wherein the strength of the pressure-bearing box body meets the requirement for the strength of the shell in the thermal runaway stage, and an explosion venting opening is formed in the pressure-bearing box body. The pressure-bearing box body has better strength, ensures a thermal runaway stage, can form a firm barrier, effectively isolates high-temperature flames and harmful gases, prevents thermal runaway from spreading, and improves the safety of the battery pack after thermal runaway.

Description

Technical Field

[0001] This utility model belongs to the field of batteries, specifically a battery pack. Background Technology

[0002] The batteries in a battery pack are usually packed tightly together. When one battery experiences thermal runaway, the resulting high temperature is quickly transferred to adjacent batteries, causing them to also experience thermal runaway. This creates a chain reaction of heat diffusion, leading to damage and loss of control of the entire battery pack. This causes the level of danger to increase exponentially, posing a significant safety risk. Summary of the Invention

[0003] The purpose of this invention is to provide a battery pack that overcomes the technical problem of low safety when existing battery packs experience thermal runaway.

[0004] The concept of this utility model is:

[0005] With the continued growth in market demand, there is a growing expectation for increasing battery energy density within the same size context. This means that the battery needs to accommodate more active materials and withstand more intense electrochemical reactions, which in turn places higher demands on the strength of the casing.

[0006] However, the actual situation is not optimistic, as the current casing strength is not keeping pace with demand. Taking a certain cell manufacturer as an example, the casing dimensions of its 280Ah and 314Ah cells are almost identical. The direct consequence of this mismatch is a sharp increase in the risk of thermal runaway.

[0007] Once these batteries are assembled into a battery pack, thermal runaway can occur. Due to insufficient shell strength and poor pressure resistance of the outer packaging, high-temperature and high-pressure gas can quickly break through the battery pack's protection and spread outwards, causing a serious safety accident.

[0008] In view of the aforementioned severe situation, this utility model takes a unique approach, focusing on the outer packaging casing as the core pressure-bearing casing. At the same time, the protective function of the battery casing itself is appropriately weakened to adapt to the basic strength requirements of the casing during the formation process and the normal charging and discharging process of the battery. This design not only effectively resists the high-pressure impact during thermal runaway with the reinforced outer packaging casing, greatly improving the overall safety of the battery pack, but also reduces production costs by reasonably reducing the excessive protective configuration of the battery casing, achieving a balance between safety and economy.

[0009] The technical solution of this utility model is to provide a battery pack, which is special in that it includes a pressure-bearing box and n semi-finished single cells arranged in the pressure-bearing box, where n is an integer greater than 1.

[0010] The semi-finished single cell includes a sealed casing and an electrode assembly located inside the sealed casing; the sealed casing is a plastic casing, and the strength of the sealed casing is P, P1≤P≤P2; where P1 is the strength requirement of the casing during the formation stage and the normal charge and discharge stage of the battery; P2 is the strength requirement of the casing during the thermal runaway stage.

[0011] The pressure tank has the strength required for the shell during thermal runaway, and it is equipped with a vent.

[0012] The outer casing of the battery pack of this utility model is a pressure-bearing casing, and its strength needs to meet the strength requirements of the shell during the thermal runaway stage; that is, the pressure-bearing casing is required to have good strength to ensure that during the thermal runaway stage, the pressure-bearing casing can form a solid barrier, effectively isolate high-temperature flames and harmful gases, prevent the spread of thermal runaway, and improve the safety of the battery pack after thermal runaway.

[0013] Furthermore, the individual cells in the battery pack of this utility model are semi-finished individual cells, and their shells are sealed shells made of plastic. As a cavity for containing electrode components and electrolyte, it has a sealing function. At the same time, the strength of the sealed shell needs to meet the strength requirements of the shell during the formation stage and the normal charge and discharge stage of the battery. That is, the sealed shell is required to have a certain strength to ensure that it will not break during the formation stage and the normal charge and discharge stage of the battery, as the internal environment of the battery changes, such as temperature and pressure. Compared with existing finished individual cells, the semi-finished individual cells have a lower cost, which in turn makes the entire battery pack have a lower cost.

[0014] Furthermore, the thickness of the sealed housing is h, where h is less than h0, and h0 is the thickness of a traditional single-cell plastic housing.

[0015] This invention features a sealed plastic casing with a relatively small thickness. While meeting the requirements for the casing during the formation and normal charge / discharge stages, the thickness of the plastic casing is minimized. A thinner plastic casing provides better thermal conductivity, allowing heat generated during charging and discharging to dissipate more quickly into the external environment. This helps reduce the internal temperature of the battery, minimizing battery aging and performance degradation caused by high temperatures.

[0016] Reducing the thickness of the plastic casing decreases the volume of the semi-finished single-cell battery. This allows more active material to be accommodated within the same battery size, increasing the battery's energy density. Thinning the plastic casing also means using less plastic material, contributing to cost savings and providing an economic advantage for large-scale production and application.

[0017] Furthermore, the pressure-bearing box is made of iron, steel, or stainless steel.

[0018] Metal shells offer advantages in terms of strength and cost, making them a viable option in scenarios where cost is a primary concern and strength requirements are not particularly stringent.

[0019] The steel casing has relatively high strength, providing more reliable protection for the battery and making it suitable for applications with high requirements for safety and structural strength.

[0020] Stainless steel casings not only possess excellent strength properties but also outstanding corrosion resistance, making them perform exceptionally well in battery applications that may face humid or corrosive environments. This effectively extends battery life and ensures stable battery operation in complex environments.

[0021] By offering a variety of metal casing options, this invention can better adapt to the usage requirements of lithium-ion batteries in different fields and under different working conditions, enabling semi-finished single cells and individual semi-finished single cells to achieve a more optimized balance in terms of safety, performance, and cost.

[0022] Furthermore, the battery pack also includes a heat exchange component that exchanges heat with the polarity terminals.

[0023] As a crucial component connecting the battery's internal structure to the external environment, the polarity terminals allow current to flow in and out of the battery during charging and discharging. When heat is generated inside the battery, the polarity terminals provide a relatively direct heat conduction path. Heat can be rapidly conducted from inside the battery to the polarity terminals, and then dissipated into the external environment from there.

[0024] 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.

[0025] Furthermore, the heat exchange component is a heat transfer tube; each of the polar terminals of the semi-finished single cell 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 of the polar terminals of the semi-finished single cell.

[0026] By utilizing 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, thereby achieving heat dissipation of the battery.

[0027] The design of through slots or holes allows for a larger contact area between the heat transfer tube and the polarity terminal. Compared to planar contact, this embedded contact method enables more efficient heat transfer between the heat transfer tube and the polarity terminal, improving heat exchange efficiency. Furthermore, the shape of the through slots or holes provides a certain degree of locking and fixing for the heat transfer tube, preventing displacement or loosening during use. Especially in vibrating or shaking operating environments, this fixing method ensures that the heat transfer tube and the polarity terminal maintain good contact at all times, guaranteeing the stability of heat exchange.

[0028] Furthermore, the heat exchange component is a heat exchange device, which is installed on top of each semi-finished single cell; the polar terminal penetrates the heat exchange device, and at least a part of the structure of the polar terminal is located in the inner cavity of the heat exchange device and is in direct contact with the heat exchange medium; another part of the structure of the polar terminal is located outside the heat exchange device and serves as an electrical connection part; the side wall of the polar terminal is sealed with the heat exchange device.

[0029] By adopting a direct heat exchange method, part of the polar terminal structure is placed directly inside the heat exchange medium flow cavity (the inner cavity of the heat exchange device), so that the polar terminal is in direct contact with the heat exchange medium, thereby realizing heat exchange of the polar terminal. Compared with the indirect heat exchange method, it has a shorter heat exchange path. The heat exchange medium acts directly on the polar terminal, improving the utilization efficiency of the heat exchange medium and improving the heat exchange efficiency of the battery.

[0030] Furthermore, each of the polar terminals of the semi-finished single-cell battery is provided with a functional structure, which is used to increase the heat exchange area of ​​the polar terminal at that location; the part of the polar terminal with the functional structure is located in the inner cavity of the heat exchange device.

[0031] Furthermore, insulating and sealing layers are provided between each semi-finished individual cell and between each semi-finished individual cell and the pressure tank; the heat exchange components are located within the insulating and sealing layers.

[0032] The insulating sealant layer can prevent condensation and improve the stability of semi-finished single cells within the pressure tank.

[0033] Furthermore, the top plate of the pressure-bearing box has clearance holes corresponding to the polarity terminals of each semi-finished individual battery; the area of ​​the top plate of the pressure-bearing box corresponding to the clearance hole is fixedly sealed with the sealing shell of the semi-finished individual battery; the polarity terminals of each semi-finished individual battery extend out of the clearance holes.

[0034] Furthermore, an insulating sealant layer is laid on the top plate of the pressure tank, and the heat exchange components are located within the insulating sealant layer. By laying an insulating sealant layer only on the top plate of the pressure tank, the amount of insulating sealant used can be reduced, thereby lowering the cost of the battery pack.

[0035] Furthermore, the capacity of the semi-finished individual battery is 280Ah or 314Ah, and n equals 13. By limiting the capacity and number of semi-finished individual batteries contained in the pressure tank, the safety performance of the battery pack of this invention can be optimized.

[0036] Furthermore, an impermeable membrane is installed between each semi-finished individual battery cell and the pressure tank to prevent the electrolyte inside each cell from seeping out. This membrane plays a crucial protective role, firmly locking in the electrolyte. This not only prevents battery performance degradation that could be caused by electrolyte leakage, but also prevents corrosion of the pressure tank, effectively ensuring the safety and stability of the entire battery, extending its lifespan, and ensuring stable operation under various working conditions.

[0037] The beneficial effects of this utility model are:

[0038] The outer casing of the battery pack of this utility model is a pressure-bearing casing, and its strength needs to meet the strength requirements of the shell during the thermal runaway stage; that is, the pressure-bearing casing is required to have good strength to ensure that during the thermal runaway stage, the pressure-bearing casing can form a solid thermal 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.

[0039] Furthermore, the individual cells in the battery pack of this utility model are semi-finished individual cells, and their shells are sealed shells made of plastic. As a cavity for containing electrode components and electrolyte, it has a sealing function. At the same time, the strength of the sealed shell needs to meet the strength requirements of the shell during the formation stage and the normal charge and discharge stage of the battery. That is, the sealed shell is required to have a certain strength to ensure that it will not break during the formation stage and the normal charge and discharge stage of the battery, as the internal environment of the battery changes, such as temperature and pressure. Compared with existing finished individual cells, the semi-finished individual cells have a lower cost, which in turn makes the entire battery pack have a lower cost. Attached Figure Description

[0040] Figure 1 This is a schematic diagram of the battery pack structure in Example 1;

[0041] Figure 2 This is a schematic diagram of the exploded structure of the battery pack in Example 1;

[0042] Figure 3 This is a schematic diagram of the structure of the semi-finished single cell in Example 1;

[0043] Figure 4 This is a schematic diagram of the exploded structure of the semi-finished single cell in Example 1;

[0044] Figure 5 This is a partial structural diagram of the battery pack in Example 2;

[0045] Figure 6 This is a partial exploded view of the battery pack structure in Example 2;

[0046] Figure 7 This is a schematic diagram of the structure of the semi-finished single cell in Example 2;

[0047] Figure 8 This is a partial structural diagram of the battery pack in Example 3;

[0048] Figure 9 This is a schematic diagram of the heat exchange tubes in Example 3;

[0049] Figure 10 This is a cross-sectional view of the heat exchanger tubes in Example 3;

[0050] Figure 11 This is a partial exploded view of the battery pack structure in Example 4. Figure 1 ;

[0051] Figure 12 This is a partial exploded view of the battery pack structure in Example 4. Figure 2 ;

[0052] Figure 13 This is a schematic diagram of the structure of the first type of heat exchange sleeve in Example 4;

[0053] Figure 14 This is a schematic diagram of the structure of the second type of heat exchange sleeve in Example 4;

[0054] Figure 15 This is a schematic diagram of the explosion of the battery pack in Example 6;

[0055] Figure 16 This is a schematic diagram of the battery pack structure in Example 6.

[0056] The attached figures are labeled as follows:

[0057] 1. Pressure tank; 11. Top plate of pressure tank; 12. Clearance hole; 2. Semi-finished single cell; 21. Sealed shell; 22. Polar terminal; 221. Through groove; 222. Annular groove; 211. Cylinder; 212. Upper cover plate; 213. Lower cover plate; 3. Heat transfer tube; 4. Heat exchange fittings; 41. Through hole; 412. Bottom port; 413. Top port; 5. Heat exchange sleeve; 311. Hollow component; 312. Annular sealing plate; 313. First through hole; 314. Liquid inlet pipe; 315. Liquid outlet pipe. Detailed Implementation

[0058] 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.

[0059] 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.

[0060] 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.

[0061] Example 1

[0062] like Figure 1 and Figure 2 The diagram shown is a structural schematic of the battery pack in this embodiment, including a pressure-bearing housing 1 and 12 semi-finished individual battery cells 2 arranged within the pressure-bearing housing 1. In other embodiments, the number of semi-finished individual battery cells 2 can be adjusted according to actual needs.

[0063] The structure of the semi-finished single cell 2 is as follows Figure 3 and Figure 4 As shown, it includes a sealed housing 21 and an electrode assembly located within the sealed housing 21.

[0064] The sealed housing 21 serves as a cavity for the electrode assembly and electrolyte, providing a sealed space for these components. The strength of the sealed housing 21 must meet certain requirements. In this embodiment, the strength of the sealed housing 21 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 normal charge / discharge processes. During the formation stage and normal charge / discharge processes, the battery undergoes a series of chemical reactions and physical changes. This process generates pressure and heat inside the battery. The sealed housing 21 needs sufficient strength to withstand this pressure and heat to ensure the smooth progress of the formation process and the normal use of the battery. To reduce cost and battery weight while meeting the aforementioned strength requirements, this embodiment uses a plastic housing as the sealed housing 21.

[0065] It can be assumed that the strength of the aforementioned sealed housing 21 is P, P1≤P≤P2; where P1 is the strength requirement of the housing during the formation stage and the normal charging and discharging stage of the battery; and P2 is the strength requirement of the housing during the thermal runaway stage.

[0066] In this embodiment, the thickness of the sealing shell 21 is h, where h is less than h0, and h0 is the thickness of the plastic shell of the existing semi-finished single-cell battery 2; the thickness of the plastic shell of the existing semi-finished single-cell battery 2 is typically 5-8 mm. In this embodiment, the thickness of the sealing shell 21 can be between 1-4 mm. By reducing the thickness of the shell of the conventional semi-finished single-cell battery 2 with a plastic shell, better heat dissipation can be achieved, while also increasing the battery energy density. Furthermore, 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] from Figure 4 As can be seen from the image, the sealing shell 21 in this embodiment is formed by a cylinder 211, an upper cover plate 212, and a lower cover plate 213.

[0068] The lower cover plate 213 and the cylinder body 211 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 213 and the cylinder body 211, and higher overall structural strength. Additionally, reinforcing ribs can be integrally molded on the cylinder body 211, effectively increasing its resistance to bending, compression, and torsion.

[0069] In this embodiment, since both the upper cover plate 212 and the cylindrical body 211 are made of plastic, a heat-sealing connection can be used. Heat-sealing ensures a continuous, uniform, and tight connection between the upper cover plate 212 and the cylindrical body 211, resulting in extremely high stability. Compared to other sealing methods, it does not loosen or leak over time, maintaining excellent sealing performance at all times. External water, dust, and other impurities cannot enter the battery, effectively protecting the electrode assembly 51 and ensuring the battery's performance and lifespan. Furthermore, the heat-sealing process is simple, and the parameters are easy to control.

[0070] It should be noted that the plastic material selected in this utility model should have the following properties:

[0071] First, it must have sufficient strength to ensure the stability of the battery structure;

[0072] Second, it has chemical corrosion resistance and can resist the corrosion of electrolytes;

[0073] Third, it has barrier properties, which can effectively prevent the electrolyte, gas and other substances inside the battery from leaking out, while also preventing external impurities such as moisture and oxygen from entering the battery. In addition, a seepage-proof membrane can be installed between each semi-finished cell and the pressure tank to prevent the electrolyte inside each semi-finished cell from seeping out.

[0074] 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.

[0075] The plastic material used can be the material used in the existing plastic shell semi-finished single cell battery 2, or the plastic material disclosed in Chinese patents CN106543551A and CN106977894A.

[0076] The semi-finished single cell 2 is installed inside the pressure-bearing housing 1. Its strength needs to meet the strength requirements of the housing during the thermal runaway stage. That is, the pressure-bearing housing is required to have good strength to ensure that it can form a solid thermal barrier during the thermal runaway stage. Even in the extreme case where the sealed housing 21 melts, 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.

[0077] Compared to other materials, the metal pressure tank 1 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 the safety of personnel and surrounding equipment. In this embodiment, the pressure tank 1 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 well in battery applications that may face humid or corrosive environments. This effectively extends battery life and ensures stable operation in complex environments.

[0078] Example 2

[0079] This embodiment is also a battery pack. Unlike embodiment 1, this embodiment adds a heat exchange component to dissipate heat from the polarity terminal 22.

[0080] like Figure 5 The figure shows a partial structural diagram of the battery pack in this embodiment (the pressure box 1 is not shown). As can be seen from the figure, the heat exchange component in this embodiment is the heat transfer pipe 3. The heat generated inside each semi-finished single cell can be conducted to the heat transfer pipe 3 through the polar terminal 22, and then the heat transfer pipe 3 dissipates the heat, thereby achieving heat dissipation for each semi-finished single cell.

[0081] In this embodiment, through slots 221 or through holes for installing heat transfer tubes 3 are provided on the two polar terminals 22.

[0082] For details, please refer to [link / reference]. Figure 7 As shown in the figure, the polar terminal 22 in this embodiment is a cylindrical body, including a second end face, a first end face, and a side face (the second end face and the first end face are parallel to each other). The second end face is provided with an electrical connection area for connection with external electrical connectors, and the first end face is used for electrical connection with the electrode assembly inside the battery casing. A through groove 221 is provided on the side face (i.e., the opening of the through groove 221 is located on the side face), which serves as a mounting part for the heat transfer tube 3 to be installed.

[0083] In some other embodiments, a through hole may be provided on the side, that is, the opening of the through hole is located on the side.

[0084] In some other embodiments, the through groove 221 may also be formed on the second end face, that is, the opening of the through groove 221 is located on the second end face.

[0085] By creating through slots 221 and through holes on the side, compared to creating through slots 221 on the second end face, the heat transfer tube 3 has a larger contact area with the inner wall of the through slot 221, resulting in higher heat exchange efficiency. Furthermore, when the through slots 221 and through holes are located on the side, the entire area of ​​the second end face can be used as an electrical connection area. Two through slots 221 or through holes can also be provided on the side of the polarity terminal 22 to increase the number of heat transfer tubes 3 and further improve heat exchange efficiency.

[0086] Furthermore, the through-slot structure 221 makes the heat transfer tube 3 easier to install compared to the through-hole structure. To further improve the ease of installation of the heat transfer tube 3, such as... Figure 3 As shown, in this embodiment, the openings of the through slots 221 on the two polarity terminals 22 face the same direction. This unidirectional orientation allows the heat transfer tube 3 to be installed along one direction, eliminating the need for complex adjustments and alignments by the operator in different directions. This significantly improves installation efficiency and accuracy, reducing the possibility of installation errors.

[0087] The cross-section of the through-slot 221 is C-shaped or U-shaped. The opening width of the C-shaped through-slot 221 is smaller than the widest part of the through-slot 221. This design is conducive to the interference fit of the heat transfer tube 3 in the through-slot 221. The arc formed by the two ends of the C-shaped through-slot 221 has natural tension, which is conducive to the tight fit of the heat transfer tube 3 in the through-slot 221. The cross-section of the U-shaped through-slot 221 is rectangular at the opening and semi-circular near the bottom of the slot. The size of the opening is slightly smaller than the widest part of the through-slot 221 and also slightly smaller than the outer diameter of the heat transfer tube 3. This design is also conducive to the interference fit of the heat transfer tube 3 in the through-slot 221 and to fixing the heat transfer tube 3 in the through-slot 221. The interference fit is mainly in the bottom area of ​​the slot with a semi-circular cross-section.

[0088] The horizontal cross-section of the polarity terminal 22 can be circular, rectangular, or racetrack-shaped. Different shapes of polarity terminals 22 can be selected according to different battery models, or other different shapes. These will not be listed exhaustively in this embodiment.

[0089] In this embodiment, the first end face of the polarity terminal 22 is close to the electrode assembly. Therefore, the first end face is closer to the internal electrode assembly of the battery, and the heat transfer pipe 3 should be positioned as close as possible to the first end face. This arrangement allows the heat transfer pipe 3 to be as close as possible to the inside of the battery for heat transfer.

[0090] from Figure 5 and Figure 6As can be seen from the figure, the heat transfer tube 3 in this embodiment is U-shaped in general, including a first tube, a second tube and a connecting tube; the first tube is fixed in the through groove 221 of the polar terminal 22 of each semi-finished single cell 2 on one side; the second tube is fixed in the through groove 221 of the polar terminal 22 of each semi-finished single cell 2 on the other side; the two ends of the connecting tube are respectively connected to the ports of the first tube and the second tube on the same side.

[0091] like Figure 6 As shown, when installing heat transfer tube 3, the first tube, the second tube and the connecting tube can be pre-assembled into one piece. Then, the first tube and the second tube are inserted into the corresponding through groove 221 in the direction shown by the arrow in the figure. The installation process is simple and convenient, which improves the installation efficiency.

[0092] Example 3

[0093] This embodiment is another type of battery pack, which differs from Embodiment 2 in that it uses a different heat exchange component to exchange heat on the polarity terminal 22.

[0094] from Figure 8 As can be seen from the diagram, the heat exchange component in this embodiment includes two heat exchange tubes 4. The two heat exchange tubes 4 are respectively disposed on the polarity terminals 22 on different sides of each semi-finished single cell. In order to improve the safety performance of each semi-finished single cell, the heat exchange tubes 4 should not be energized. In this embodiment, heat exchange tubes 4 made of insulating material can be selected. In some other embodiments, the non-insulated heat exchange tubes 4 can be insulated, such as by spraying insulating paint or wrapping with insulating film. An insulating sealing gasket can also be added between the polarity terminal 22 and the heat exchange tubes 4 to achieve the above purpose.

[0095] The structure of heat exchanger tube 4 is as follows Figure 9 and Figure 10 As shown in the figure, the heat exchange tube 4 in this embodiment has 12 through holes 41. The 12 through holes 41 are arranged along the x-direction and correspond one-to-one with the polarity terminals 22 of each semi-finished single cell 2. In some other embodiments, the number of through holes 41 can be adjusted according to the number of semi-finished single cells 2 in each semi-finished single cell, and the arrangement of the through holes 41 can be adjusted according to the arrangement of the semi-finished single cells 2.

[0096] The aforementioned through hole 41 is a through hole 41 that penetrates the top plate and bottom plate of the heat exchange tube 4 and communicates with the inner cavity of the heat exchange tube 4. In this embodiment, after the heat exchange tube 4 is fixed to the top of the semi-finished single cell 2, the extension direction of the through hole 41 is consistent with the height direction (i.e., the z direction) of the semi-finished single cell 2. Therefore, it can be considered that the through hole 41 extends along the z direction.

[0097] In addition, when the heat exchange tube 4 is fixed on the top of the semi-finished single cell 2, the electrical connection part of the polarity terminal 22 of each semi-finished single cell 2 passes through the bottom port 412 of the corresponding through hole 41 and extends out from the top port 413, and the polarity terminal 22 is sealed with the hole wall of the through hole 41. The top port 413 here is the port near the electrical connection part of the polarity terminal 22.

[0098] from Figure 8 As can be seen from the diagram, in this embodiment, the two heat exchange tubes 4 are respectively fitted onto the polarity terminals 22 on different sides of each semi-finished single cell based on the through holes 41, and the two heat exchange tubes 4 are connected in series through connecting pipes. In some other embodiments, the two heat exchange tubes 4 can also be connected in parallel.

[0099] In addition, this embodiment can also provide a functional structure on the polarity terminal 22 to increase the heat exchange area of ​​that part of the polarity terminal 22.

[0100] For details, please refer to [link / reference]. Figure 3 In this embodiment, at least two annular grooves 222 are formed on the sidewall of the polarity terminal 22. The two annular grooves 222 are arranged along the height direction of the polarity terminal 22, and each annular groove 222 extends circumferentially along the sidewall of the polarity terminal 22. The heat exchange area of ​​this part of the polarity terminal 22 can be increased by the two annular grooves 222. Placing the part with the functional structure in the heat exchange medium flow cavity can further improve the heat exchange effect.

[0101] In some other embodiments, the number of annular grooves 222, as well as the dimensions such as groove width and groove depth, can be adjusted as needed, provided that the conductivity of the polarity terminal 22 is not affected.

[0102] In other embodiments, other structures can be processed on the polar terminal 22 to increase the heat exchange area of ​​the polar terminal 22. Such functional structures may include dot-shaped pits or protrusions on the sidewall of the polar terminal 22, and may also include through holes on the polar terminal 22 (heat dissipation teeth can be added along its axial direction in the through hole to further increase the heat exchange area in the through hole). Compared with the above functional structures, the annular groove 222 structure in this embodiment is easier to process and has a lower processing cost.

[0103] This embodiment adopts a direct heat exchange method, in which part of the structure of the polar terminal 22 is placed directly in the inner cavity of the heat exchange tube 4, so that the polar terminal 22 is in direct contact with the heat exchange medium, thereby realizing heat exchange of the polar terminal 22. Compared with the indirect heat exchange method (the heat exchange method of embodiment 3), it has a shorter heat exchange path. The heat exchange medium acts directly on the polar terminal 22, improving the utilization efficiency of the heat exchange medium and improving the heat exchange efficiency of the battery.

[0104] Example 4

[0105] This embodiment is another type of battery pack, which differs from embodiment 3 in that it uses a different heat exchange component to exchange heat on the polarity terminal 22.

[0106] Combination Figure 11 and Figure 12 As can be seen, the heat exchange component in this embodiment includes 24 heat exchange sleeves 5, which are respectively set around the 24 polar terminals 22.

[0107] The structure of heat exchange sleeve 5 is as follows Figure 13 As shown, it includes a hollow component 311 and an annular sealing plate 312; two first through holes 313 are opened on the side wall of the hollow component 311 to penetrate its inner cavity, which serve as liquid inlet and liquid outlet respectively; the annular sealing plate 312 is coaxial with the hollow component 311 and is sealed and fixed at the top of the hollow component 311.

[0108] Combination Figure 11 As can be seen, the heat exchange sleeve 5 is sleeved around the polar terminal 22, forming an annular cavity between it and the side wall of the polar terminal 22 (which may have an annular groove 222). This annular cavity serves as a flow cavity for the heat exchange medium. The bottom end of the hollow component 311 is sealed and fixed to the polar terminal 22 of the semi-finished single cell 2. The inner ring surface of the annular sealing plate 312 is sealed and fixed to the side wall of the polar terminal 22. At the same time, part of the structure of the polar terminal 22 extends out of the inner hole of the annular sealing plate 312, serving as the electrical connection part of the polar terminal 22.

[0109] This utility model does not specifically limit the cross-sectional shape of the hollow component 311. Generally, the cross-sectional shape of the hollow component 311 is adapted to the cross-sectional shape of the polar terminal 22. For example, when the cross-section of the polar terminal 22 is circular, the cross-section of the corresponding hollow component 311 is annular; when the cross-section of the polar terminal 22 is square, the cross-section of the corresponding hollow component 311 is square annular.

[0110] In this embodiment, the hollow component 311 and the annular sealing plate 312 are an integral part. In some other embodiments, the hollow component 311 and the annular sealing plate 312 can be separate parts, but the processing is more complicated than in this embodiment.

[0111] In this embodiment, the heat exchange sleeve 5 is made of rubber, which has a certain elastic deformation. The bottom end of the hollow component 311 and the polar terminal 22 are tightly fitted together to achieve a sealed fixation. To improve the sealing reliability, insulating sealant can also be used for bonding. The inner ring surface of the annular sealing plate 312 and the side wall of the polar terminal 22 are sealed by a tight fit. In some other embodiments, an annular sealing ring can be added between the inner ring surface of the annular sealing plate 312 and the side wall of the polar terminal 22 to further improve the sealing performance.

[0112] In some other embodiments, the bottom end of the heat exchange sleeve 5 can also be sealed and fixed to the top cover plate 212 of the semi-finished single cell battery 2 to ensure the seal between the hollow component 311 and the side wall of the polar terminal 22.

[0113] like Figure 11 As shown, in this embodiment, the heat exchange sleeves 5 on the same side of each semi-finished single cell 2 are connected to form two heat exchange channels on the top of the 12 semi-finished single cells 2. The two heat exchange channels can be connected in parallel or in series, and heat exchange is achieved based on the two heat exchange channels.

[0114] In this embodiment, as Figure 14 As shown, the heat exchange sleeve 5 also includes an inlet pipe 314 and an outlet pipe 315; the inlet pipe 314 and the outlet pipe 315 are both fixed on the side wall of the hollow component 311 and are respectively connected to the inlet and outlet.

[0115] The hollow component 311, the annular sealing plate 312, the liquid inlet pipe 314 and the liquid outlet pipe 315 are integrated into one piece, and all of them are made of insulating material, preferably an insulating material with a certain degree of elastic deformation.

[0116] It should be noted that the inlet pipe 314 of one heat exchanger 5 and the outlet pipe 315 of the other heat exchanger 5 can be connected to each other to achieve communication between the two adjacent heat exchanger 5. Alternatively, a connecting pipe section can be used to connect the inlet pipe 314 of one heat exchanger 5 and the outlet pipe 315 of the other heat exchanger 5 to achieve communication between the two adjacent heat exchanger 5.

[0117] This embodiment can adopt the following two installation methods to fix the heat exchange component to each semi-finished single cell 2:

[0118] Installation Method 1:

[0119] like Figure 11 As shown, each heat exchange sleeve 5 is fitted onto the corresponding polarity terminal 22 one by one. During the fitting process, adjacent heat exchange sleeves 5 are connected, and the top and bottom open ends of the heat exchange sleeve 5 are sealed to the side wall of the polarity terminal 22; finally, two heat exchange channels are formed.

[0120] Installation Method Two:

[0121] like Figure 12As shown, firstly, the heat exchange sleeves 5 are connected to form two heat exchange channels. Then, each heat exchange channel is installed as a whole on top of 12 semi-finished single cells 2. During the installation process, each heat exchange sleeve 5 of each heat exchange channel is fitted onto the corresponding polarity terminal 22 to complete the sealing between the open top and bottom ends of the heat exchange sleeve 5 and the side wall of the polarity terminal 22; finally, two heat exchange channels are formed.

[0122] By adopting a direct heat exchange method, a portion of the structure of the polar terminal 22 is placed directly inside the heat exchange sleeve 5, allowing the polar terminal 22 to directly contact the heat exchange medium and achieve heat exchange of the polar terminal 22. Compared with the indirect heat exchange method (the heat exchange method in Example 4), it has a shorter heat exchange path, and the heat exchange medium acts directly on the polar terminal 22, improving the utilization efficiency of the heat exchange medium and improving the heat exchange efficiency of the battery.

[0123] Example 5

[0124] Based on Examples 2, 3 and 4, this embodiment adds an insulating and sealing layer between each semi-finished individual battery cell 2 and between each semi-finished individual battery cell 2 and the pressure-bearing box 1.

[0125] The insulating sealant layer is mainly laid in the space between each semi-finished single cell 2 and the pressure tank 1. The heat exchange components inside the pressure tank 1 are all located within the insulating sealant layer. At the same time, the electrical connectors connected to the polar terminals 22 inside the pressure tank 1 can also be located within the insulating sealant layer (when it is necessary to collect signals from the electrical connectors, the electrical connectors need to be exposed within the insulating sealant layer). When there is a gap between each semi-finished single cell 2, the insulating sealant liquid can also penetrate into the gap to form an insulating sealant layer.

[0126] In this embodiment, the insulating sealant layer has at least the following advantages:

[0127] 1. Prevent condensation;

[0128] During prolonged use, condensation will form on the surface of the heat exchange components due to the temperature difference between the inside and outside. 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 components, the condensation on the surface of the heat exchange components can be protected from short circuits.

[0129] II. Further improve the stability of each semi-finished single cell 2 within the pressure-bearing box 1;

[0130] The insulating sealant penetrates into the gaps between each semi-finished cell 2 and between each semi-finished cell 2 and the pressure tank 1, which can further improve the stability of each semi-finished cell 2 within the pressure tank 1.

[0131] Third, further improve the sealing performance of each part of the heat exchange components;

[0132] Specifically, the insulating sealant that forms the insulating sealant layer penetrates into the gap between the heat exchange sleeve 5 and the side wall of the polar terminal 22 or the gap between the through hole 41 and the side wall of the polar terminal 22, further sealing the gap radially (the insulating sealant cannot flow into the heat exchange medium flow cavity through the gap between the heat exchange sleeve 5 and the side wall of the polar terminal 22 or the gap between the through hole 41 and the side wall of the polar terminal 22).

[0133] Example 6

[0134] This embodiment is also a high-capacity battery, but it differs from embodiment 5 in that... Figure 15 and Figure 16 As shown, in this embodiment, clearance holes 12 are provided on the top plate 11 of the pressure-bearing box corresponding to the polarity terminals 22 of each semi-finished individual battery 2; the polarity terminals 22 of each semi-finished individual battery 2 extend out of the clearance holes 12; the area of ​​the top plate 11 of the pressure-bearing box corresponding to the clearance holes 12 is fixedly sealed to the sealing shell 21 of the semi-finished individual battery 2. The heat exchange component is fixed on the part where the polarity terminals 22 extend out of the clearance holes.

[0135] In this embodiment, an insulating sealant layer can be laid only on the top plate 11 of the pressure tank, and the heat exchange component is located inside the insulating sealant layer. When condensation occurs on the surface of the heat exchange component, the battery short circuit can also be prevented under the protection of the insulating sealant layer.

[0136] Compared to Example 5, this example can significantly reduce the amount of insulating sealant used, thereby reducing battery costs.

Claims

1. A battery pack, characterized in that: It includes a pressure-bearing box and n semi-finished individual batteries arranged inside the pressure-bearing box, where n is an integer greater than 1; The semi-finished single cell includes a sealed casing and an electrode assembly located inside the sealed casing; the sealed casing is a plastic casing, and the strength of the sealed casing is P, P1≤P≤P2; where P1 is the strength requirement of the casing during the formation stage and the normal charge and discharge stage of the battery; P2 is the strength requirement of the casing during the thermal runaway stage. The pressure tank has the strength required for the shell during thermal runaway, and it is equipped with a vent.

2. The battery pack according to claim 1, characterized in that: The thickness of the sealed housing is h, where h is less than h0, and h0 is the thickness of the plastic housing of a traditional single battery cell.

3. The battery pack according to claim 1, characterized in that: The pressure-bearing box is made of iron, steel, or stainless steel.

4. The battery pack according to claim 1, characterized in that: It also includes heat exchange components that exchange heat with the polarity terminals.

5. The battery pack according to claim 4, characterized in that: The heat exchange component is a heat transfer tube; each of the polar terminals of the semi-finished single cell 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 of the polar terminals of the semi-finished single cell.

6. The battery pack according to claim 4, characterized in that: The heat exchange component is a heat exchange device, which is installed on top of each semi-finished single cell. The polar terminal penetrates the heat exchange device, and at least a part of the structure of the polar terminal is located in the inner cavity of the heat exchange device and is in direct contact with the heat exchange medium. Another part of the structure of the polar terminal is located outside the heat exchange device and serves as an electrical connection part. The side wall of the polar terminal is sealed with the heat exchange device.

7. The battery pack according to claim 6, characterized in that: The polar terminals of the semi-finished single-cell batteries are provided with functional structures, which are used to increase the heat exchange area of ​​the polar terminals at that location; the part of the polar terminals with functional structures is located in the inner cavity of the heat exchange device.

8. The battery pack according to claim 4, characterized in that: Insulating sealant layers are provided between each semi-finished cell and between each semi-finished cell and the pressure tank; the heat exchange components are located within the insulating sealant layers.

9. The battery pack according to claim 4, characterized in that: The top plate of the pressure tank has clearance holes corresponding to the polarity terminals of each semi-finished single cell; the area of ​​the top plate of the pressure tank corresponding to the clearance hole is fixedly sealed with the sealing shell of the semi-finished single cell; the polarity terminals of each semi-finished single cell extend out of the clearance hole.

10. The battery pack according to claim 9, characterized in that: An insulating sealant layer is laid on the top plate of the pressure tank, and the heat exchange components are located inside the insulating sealant layer.

11. The battery pack according to claim 1, characterized in that: The capacity of the semi-finished single cell is 280Ah or 314Ah, and n equals 13.

12. The battery pack according to claim 1, characterized in that: An anti-seepage membrane is installed between each semi-finished cell and the pressure tank to prevent the electrolyte inside each semi-finished cell from seeping out.

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