Battery module and battery pack

Abstract

The utility model discloses a battery module and battery pack, be provided with the explosion vent on the battery module, the bottom surface of explosion vent is provided with N first through -hole, the top surface of battery group string and the bottom surface of explosion vent are provided with the thermal expansion body between, the thermal expansion body is provided with N second through -hole with N first through -hole one -to -one correspondence and keeps the intercommunication on, the thermal expansion body expands when the battery temperature rise, make the bottom surface of explosion vent and the thermal expansion body between, and the thermal expansion and each monomer battery top surface close adhesion, ensure that the thermal runaway flue gas can only from the smoke outlet of explosion vent and export, avoided the thermal runaway flue gas from the area of explosion vent and monomer battery between leakage, promoted the reliability of flue gas orderly discharge.

Description

Technical Field

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

[0002] Currently, most common battery modules are composed of multiple individual battery cells connected together electrically.

[0003] Fire protection of battery modules has always been a hot topic of concern in this field. During the operation of a battery module, any single cell may experience diaphragm collapse and internal short circuit due to factors such as overcharging, over-discharging, overheating, or mechanical collisions, leading to thermal runaway. The resulting thermal runaway fumes can spread within the battery module, potentially causing thermal runaway risks in other single cells and resulting in more serious safety hazards. Utility Model Content

[0004] The first aspect of this utility model provides a battery module that, by setting a venting pipe on the battery module, can orderly discharge thermal runaway fumes, thus overcoming the problem that thermal runaway of a single battery cell may affect other single batteries, thereby causing more serious safety hazards.

[0005] The battery module includes N individual cells arranged along the thickness direction of the individual cells. The first and last individual cells are each provided with a clamping plate on their outer side and are wrapped and bound with steel strips to form a battery string. Its improvement is that it also includes a venting pipe fixed on the battery string.

[0006] The bottom surface of the explosion relief pipe has N first through holes;

[0007] A thermal expansion body is installed between the top surface of the battery string and the bottom surface of the explosion relief pipe; the thermal expansion body is provided with N second through holes that correspond one-to-one with the N first through holes and are kept in communication; the thermal expansion body expands when the battery heats up, so that the bottom surface of the explosion relief pipe and the thermal expansion body, as well as the thermal expansion body and the top surface of each individual battery, are in close contact, ensuring that the thermal runaway smoke can only be discharged from the smoke outlet of the explosion relief pipe.

[0008] This invention adds a venting pipe to the battery module, which can be used to orderly discharge thermal runaway fumes, preventing the thermal runaway fumes from spreading inside the battery module and improving the safety of the battery module after thermal runaway.

[0009] In addition, a thermal expansion body is provided between the explosion relief pipe and the individual battery in this invention. When the temperature of the individual battery casing rises rapidly before thermal runaway occurs, the thermal expansion body expands. When thermal runaway occurs, under the action of the expansion force, the thermal expansion body fits tightly with the bottom surface of the explosion relief pipe and the top surface of the individual battery, which prevents thermal runaway flue gas from leaking from the area between the explosion relief pipe and the individual battery, and improves the reliability of orderly flue gas emission.

[0010] Meanwhile, the thermal expansion body ensures a seal between the vent pipe and the individual battery cells in the event of thermal runaway. The structure is simple and easy to assemble.

[0011] In this invention, the thermally expanded body can take the following two forms:

[0012] Form 1: The thermal expansion body is a long strip of gasket. The size of the long strip of gasket is adapted to the bottom size of the explosion relief pipe. N second through holes are opened on the long strip of gasket. The N second through holes correspond one-to-one with the N first through holes and are interconnected.

[0013] Form 2: The thermal expansion body consists of N annular gaskets. One annular gasket is placed between the top surface of each individual cell and the bottom surface of the vent pipe, and the area enclosed by the annular gasket must completely cover the vent of the individual cell when projected onto the top surface of the individual cell.

[0014] In order to achieve the positioning of the annular gasket and prevent the annular gasket from shifting horizontally under the pressure impact of thermal runaway flue gas, which would lead to flue gas leakage, the bottom surface of the explosion relief pipe is provided with N grooves, and an annular gasket is embedded in each groove; or a groove is opened on the top surface of each individual battery, and an annular gasket is embedded in each groove.

[0015] Alternatively, a long strip of flame-retardant rubber sheet can be added, with the length and width of the strip being equivalent to that of the explosion relief pipe, and N positioning holes can be opened on it; N annular gaskets can be embedded in the N positioning holes to achieve positioning of the annular gaskets.

[0016] Furthermore, the aforementioned explosion vent is made of metal and includes a tube body and connecting bodies on both sides of the tube body in the width direction. At least one reinforcing rib is provided inside the tube body, and N first through holes are provided on the bottom surface of the tube body. The connecting bodies on both sides are used to fix the tube body to the clamping plates at both ends by screws. In this invention, the explosion vent uses a threaded connection to press the thermally expanded body between the explosion vent and the individual battery, making the connection convenient. Compared to welding the explosion vent onto the individual battery, this method is simpler and has lower manufacturing costs. The threaded connection also avoids the problem of high temperatures during welding potentially damaging the internal structure of the individual battery. Furthermore, this press-fit explosion vent, as a fire-fighting structure, improves the safety of the battery module after thermal runaway without altering any other structures of the original battery module.

[0017] Furthermore, the battery module also includes a locking nut and a separator; two studs are spaced apart at the top of the separator; the separator is clamped and fixed between adjacent individual cells, and the two studs pass through the mounting holes of the two side connectors respectively, with the locking nut locked at the part where the studs pass through the mounting holes.

[0018] In this embodiment, the locking nut and the separator are used as the fixing parts in the middle area of ​​the explosion relief tube in the battery module, which can prevent the middle area of ​​the explosion relief tube from twisting and deforming. Combined with the connection between the two ends of the explosion relief tube and the clamping plate, the sealing reliability is further improved.

[0019] In addition, the separator has a certain degree of elasticity. When a single cell swells and deforms, the separator is squeezed by the single cell and undergoes elastic deformation. After the separator undergoes elastic deformation, it can provide expansion space for the expansion of the single cell.

[0020] Meanwhile, the heat generated during the charging and discharging of each individual battery can be transferred to the outside through the separator, reducing the risk of thermal runaway.

[0021] Furthermore, in order to improve the reliability of the explosion relief pipe fixing, two limiting plates are also provided at the bottom of the separator; both limiting plates are perpendicular to the separator body and parallel to the lower cover of the single cell. The two limiting plates extend to different sides of the separator body and limit the lower cover of two adjacent single cells.

[0022] Another aspect of this utility model provides a battery pack, characterized in that it includes a support platform, a liquid cooling plate, an outer cover, a flue gas emission pipe, and a plurality of battery modules as described in the first aspect.

[0023] Multiple battery modules are installed side by side on a support platform, and a liquid cooling plate is installed between the bottom of the multiple battery modules and the support platform;

[0024] The smoke outlet of the explosion relief pipe in each battery module is connected to the flue gas emission pipe;

[0025] The outer cover includes a top plate and four side plates; the four side plates of the outer cover are fixed to a support platform, and multiple battery modules are located inside the outer cover.

[0026] One of the side panels integrates the BMS slave unit, fire alarm interface, liquid cooling medium interface, and electrical signal interface.

[0027] The battery pack of this invention connects the explosion relief pipes of multiple battery modules to the flue gas emission pipe. The thermal runaway vent on the side plate of the battery pack can be used to orderly discharge the thermal runaway fumes outside the battery pack, avoiding the problem of thermal runaway fumes spreading inside the battery pack and affecting other modules, thereby improving the safety of the battery pack.

[0028] This utility model has at least the following beneficial effects:

[0029] 1. This utility model adds a venting pipe to the battery module, which can be used to discharge thermal runaway fumes in an orderly manner, preventing the thermal runaway fumes from spreading inside the battery module and improving the safety of the battery module after thermal runaway occurs.

[0030] In addition, a thermal expansion body is provided between the explosion relief pipe and the individual battery in this invention. When thermal runaway occurs, the temperature of the individual battery casing rises rapidly, and the thermal expansion body expands. When thermal runaway occurs, under the action of expansion force and pre-pressure, the thermal expansion body and the bottom surface of the explosion relief pipe, as well as the thermal expansion body and the top surface of the individual battery, are tightly fitted to prevent thermal runaway flue gas from leaking from the area between the explosion relief pipe and the individual battery, thereby improving the reliability of orderly flue gas emission.

[0031] Meanwhile, the thermal expansion body ensures a seal between the vent pipe and the individual battery cells in the event of thermal runaway. The structure is simple and easy to assemble.

[0032] 2. The explosion relief pipe of this utility model consists of a pipe body and a connecting body and is made of metal material. At the same time, at least one reinforcing rib is provided in the pipe body. Therefore, the explosion relief pipe has sufficient strength to prevent deformation during the pressing process. Moreover, the setting of the reinforcing rib can also ensure the pressure resistance of the explosion relief pipe in the event of thermal runaway.

[0033] 3. In this utility model, the explosion relief pipe is connected by threads (i.e., the explosion relief pipe is fixed to the battery string by a partition plate with studs, or the two ends of the explosion relief pipe are threaded to the clamping plates at both ends of the battery string) to press the thermal expansion body between the explosion relief pipe and the individual battery. The connection is convenient. Compared with the method of welding to set the explosion relief pipe on the individual battery, the setting of the explosion relief pipe is simpler and the manufacturing cost is lower. Moreover, the threaded crimping method also avoids the problem that the high temperature during the welding process may damage the internal structure of the individual battery. At the same time, the explosion relief pipe, which is a fire protection structure, can improve the safety of the battery module after thermal runaway without modifying any other structure of the original battery module.

[0034] 4. The battery pack of this utility model uses a flue gas emission pipe to connect the explosion relief pipes of multiple battery modules. At the same time, the thermal runaway vent on the side plate of the battery pack is used to orderly discharge the thermal runaway fumes outside the battery pack, avoiding the problem of thermal runaway fumes spreading inside the battery pack and affecting other modules, thereby improving the safety of the battery pack. Attached Figure Description

[0035] Figure 1 This is a structural diagram of the battery module in Example 1;

[0036] Figure 2 for Figure 1 A sectional view;

[0037] Figure 3 Structure of the explosion relief pipe Figure 1 ;

[0038] Figure 4 Structure of the explosion relief pipe Figure 2 ;

[0039] Figure 5 This is a structural diagram of a long strip pad;

[0040] Figure 6 This is a structural diagram of a ring-shaped gasket;

[0041] Figure 7 This is a structural diagram of the battery module in Example 2;

[0042] Figure 8 This is a structural diagram of the partition;

[0043] Figure 9 This is a schematic diagram of the battery pack.

[0044] Figure 10 This is a structural diagram of the battery pack after the outer cover has been removed.

[0045] The attached figures are labeled as follows:

[0046] 100 - Battery module; 200 - Battery pack;

[0047] 1-Single battery, 2-Clamping plate, 3-Steel strip, 4-Explosion relief pipe, 41-First through hole, 42-Groove, 43-Pipe body, 44-Connector, 45-Reinforcing rib, 5-Heat expansion body, 51-Second through hole, 52-Long strip gasket, 53-Annular gasket, 6-Locking nut, 7-Separator, 71-Separator body, 72-Stud, 73-Limiting plate, 8-Supporting platform, 9-Liquid cooling plate, 10-Outer cover, 101-Top plate, 102-Side plate, 103-BMS slave unit, 104-Fire interface, 105-Liquid cooling medium interface, 106-Electrical signal interface, 11-Flue gas emission pipe. Detailed Implementation

[0048] 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.

[0049] 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.

[0050] 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.

[0051] The design concept of this utility model is:

[0052] This utility model proposes a battery module, including a battery string composed of N individual batteries; a venting pipe is added to the battery string, the venting pipe is fixed to the battery string and covers the venting port of each individual battery; N first through holes are opened on the bottom surface of the venting pipe; a thermal expansion body is set between the top surface of the battery string and the bottom surface of the venting pipe, and the venting pipe provides pre-pressure to the thermal expansion body, and a second through hole is set on the thermal expansion body; the venting pipe can be used to orderly discharge thermal runaway fumes, avoiding the spread of thermal runaway fumes in the battery module and improving the safety of the battery module after thermal runaway;

[0053] In addition, a thermal expansion body is provided between the explosion relief pipe and the individual battery in this invention. When thermal runaway occurs, the temperature of the individual battery casing rises rapidly, and the thermal expansion body expands. When thermal runaway occurs, under the action of the expansion force, the thermal expansion body and the bottom surface of the explosion relief pipe, as well as the thermal expansion body and the top surface of the individual battery, fit tightly to prevent thermal runaway flue gas from leaking from the area between the explosion relief pipe and the individual battery, thereby improving the reliability of orderly flue gas emission.

[0054] Meanwhile, the thermal expansion body ensures a seal between the vent pipe and the individual battery cells in the event of thermal runaway. The structure is simple and easy to assemble.

[0055] It should be noted that:

[0056] 1. The thermal expansion body in this application can also be called a fireproof expansion seal, which needs to have the characteristics of thermal expansion and also needs to have a certain high temperature resistance.

[0057] 2. The single cell adopts a square aluminum-cased lithium battery, including a shell consisting of a top cover, a cylindrical body, and a bottom cover; and an electrode assembly located inside the shell; the electrode assembly here consists of a positive electrode, a separator, and a negative electrode arranged in sequence, assembled using a stacking or winding process. This commercially available square aluminum-cased lithium battery has completed processes such as electrolyte filling and formation.

[0058] Example 1

[0059] like Figure 1-6 As shown, this embodiment provides a battery module 100, in which N individual cells 1 are arranged along the thickness direction of the individual cells, N≥2; clamping plates 2 are respectively provided at the beginning and end, and steel strips 3 are used to bind them, thereby forming a battery string; the steel strips 3 and clamping plates 2 can effectively suppress the problem of individual cells expanding and affecting the cycle performance of the battery module.

[0060] In order to orderly discharge the flue gas after thermal runaway of the battery module, in this embodiment, the battery module 100 also includes a venting pipe 4 covering the venting port of each individual battery 1.

[0061] Figures 2 to 4 As shown, N first through holes 41 are opened on the bottom surface of the explosion relief pipe 4; a thermal expansion body 5 is provided between the top surface of each individual battery 1 and the bottom surface of the explosion relief pipe 4, such as Figure 2 As shown, the thermal expansion body 5 is provided with N second through holes 51 that correspond one-to-one with the N first through holes and are kept in communication. Preferably, the projection of the second through holes 51 on the top surface of the single cell needs to completely cover the explosion vent of the single cell.

[0062] The explosion relief pipe 4 is fixedly installed on the battery string. In order to improve the sealing effect, the installed explosion relief pipe can provide pre-pressure to the thermal expansion body 5 to press the thermal expansion body 5 tightly onto its corresponding single cell 1. The explosion relief pipe 4 and each thermal expansion body 5 are tightly fitted. The N first through holes 41 of the explosion relief pipe 4 and the N second through holes 51 of the thermal expansion body 5 are connected one by one to ensure that the thermal runaway flue gas can only be discharged from the flue outlet of the explosion relief pipe.

[0063] In this embodiment, the thermal expansion body can take the following two forms:

[0064] Form 1: such as Figure 5 As shown, the thermal expansion body 5 is a long strip of gasket 52. The size of the long strip of gasket is adapted to the bottom surface size of the explosion relief pipe. The long strip of gasket 52 has N second through holes 51. The N second through holes 51 correspond one-to-one with the N first through holes 41 and are interconnected. It should be noted that the "adaptation" mentioned here specifically means that the length of the long strip of gasket is basically the same as the length of the explosion relief pipe, and the width is also basically the same.

[0065] Form 2: such as Figure 6As shown, the thermal expansion body 5 consists of N annular gaskets 53. An annular gasket 53 is provided between the top surface of each individual cell 1 and the bottom surface of the explosion relief pipe 4, and the area enclosed by the annular gasket 53 must completely cover the explosion relief port of the individual cell when projected onto the top surface of the individual cell.

[0066] To achieve the positioning of the annular gasket and prevent displacement of the annular gasket due to thermal runaway flue gas pressure impact, which could lead to flue gas leakage, this embodiment provides a positioning method, such as... Figure 4 As shown, the bottom surface of the explosion relief pipe 4 has N grooves 42, and each groove is fitted with an annular gasket; or each individual battery 1 has a groove on its top surface, and each groove is fitted with an annular gasket.

[0067] In some other embodiments, an elongated flame-retardant rubber sheet may be added; the elongated flame-retardant rubber sheet is provided with N positioning holes, and each positioning hole is fitted with an annular gasket.

[0068] In some other embodiments, the thermal expansion body 5 may also be a thermal expansion adhesive applied to the bottom surface of the explosion relief pipe 4 or to the top surface of each individual battery cell 1.

[0069] In this embodiment, the aforementioned explosion relief pipe 4 is made of a metal material, such as steel or aluminum. Since the explosion relief pipe 4 needs to provide downward pressure to the sealing gasket, to ensure the explosion relief pipe has higher strength and prevent deformation under the applied downward pressure, as follows: Figure 2 As shown, in this embodiment, the explosion relief pipe 4 includes a pipe body 43 and connecting bodies 44 on both sides of the pipe body 43. At least one reinforcing rib 45 is provided inside the pipe body 43, and N first through holes 41 are provided on the bottom surface of the pipe body 43. For ease of processing, the structure of the explosion relief pipe 4 can be integrally formed by extrusion.

[0070] In this embodiment, the battery string has a clamping plate 2 and a steel strip 3 (this is also a common method for grouping multiple individual batteries in existing battery modules). The two ends of the explosion venting pipe 4 are connected to the two clamping plates 2 respectively, thereby fixing the explosion venting pipe to the battery string. Specifically, the connection method is as follows: the connecting bodies 44 on both sides of the explosion venting pipe 4 and the clamping plates 2 are connected by screws to fix the explosion venting pipe 4 to the battery string. This embodiment cleverly uses the clamping plates 2 to fix the explosion venting pipe 4, eliminating the need for additional fasteners to fix the explosion venting pipe, making the structure simpler.

[0071] Meanwhile, in this embodiment, the explosion relief pipe 4 is pressed and fixed to the battery string by the clamping plate 2 and screw connection. Without changing any other structure of the original battery module, the battery string can be equipped with the function of orderly discharge of thermal runaway smoke, thereby improving the safety of the battery module after thermal runaway.

[0072] Example 2

[0073] This embodiment is basically the same in structure as Embodiment 1, except that the method of fixing the explosion relief pipe 4 is different in this embodiment compared to Embodiment 1.

[0074] Specifically, in this embodiment, as Figure 7 As shown, the battery module also includes a locking nut 6 and a separator 7; a separator 7 is provided between at least one set of two adjacent individual cells 1 in the battery module, wherein the number of separators 7 is the same as the number of mounting holes on each connector 44.

[0075] The structure of partition 7 is as follows Figure 8 As shown in the figure, the separator 7 in this embodiment includes a separator body 71, two studs 72 disposed at the top of the separator body 71, and two limiting plates 73 disposed at the bottom of the separator body 71. The two studs 72 extend along the height direction of the single cell and are arranged along the width direction of the single cell. The two studs 72 correspond to two mounting holes on the two connecting bodies that are located on the same straight line. The two limiting plates 73 are perpendicular to the separator body 71 and parallel to the lower cover plate of the single cell. The two limiting plates 73 extend to different sides of the separator body 71.

[0076] See Figure 7 and Figure 8 As can be seen, when the above-mentioned separator 7 is fixed between two adjacent single cells 1, the separator body 71 is in contact with the large surface of the adjacent single cell 1, the two limiting plates 73 are limited on the lower cover plates of the two single cells 1, the two studs 72 pass through the corresponding mounting holes, and the locking nut 6 is set at the top of the stud 72.

[0077] In this embodiment, the vent pipe is connected in series with the battery pack via the following process, which can be referred to... Figure 7 :

[0078] First, fix the separator 7 between adjacent individual cells 1, so that the two limiting plates 73 are limited to the lower cover plates of different individual cells 1.

[0079] Secondly, a thermal expansion body 5 is set on the top surface of the battery string to ensure that the projection of each second through hole 51 of the thermal expansion body completely covers the explosion vent of the corresponding single cell.

[0080] Next, place the explosion relief pipe 4 on the thermal expansion body 5, ensuring that each first through hole 41 of the explosion relief pipe 4 corresponds to and is connected to each second through hole 51 of the thermal expansion body, so that the studs 72 on the partition plate 7 pass through the corresponding mounting holes.

[0081] Finally, tighten the locking nut 6 onto the stud 72. The stud 72 generates axial tension, which, under the limiting action of the limiting plate 73, clamps the thermal expansion body between the explosion relief pipe and the battery string, and ensures that the top surface of the thermal expansion body is in close contact with the bottom surface of the explosion relief pipe and the bottom surface of the thermal expansion body is in close contact with the top surface of the individual battery.

[0082] In this embodiment, the partition 7 has at least the following advantages:

[0083] Firstly, as a fixing part between the battery string and the explosion relief pipe, it can prevent the explosion relief pipe from twisting and deforming in the middle area. Combined with the connection between the two ends of the explosion relief pipe and the clamping plate, it further improves the sealing reliability.

[0084] Secondly, the separator 7 has a certain elasticity. When the single cell 1 swells and deforms, the separator 7 is squeezed by the single cell 1 and undergoes elastic deformation. After the separator 7 undergoes elastic deformation, it can provide expansion space for the expansion of the single cell 1.

[0085] Thirdly, the heat generated during the charging and discharging of each individual battery cell 1 can be transferred to the outside through the separator 7, reducing the risk of thermal runaway.

[0086] The presence of the separator can suppress the expansion of individual cells and fix the vent pipe. In some embodiments, in order to save the volume and weight of the battery module and reduce the cost of the battery module, the steel strip and clamping plate can be eliminated.

[0087] Example 3

[0088] like Figures 9 to 10 As shown, this embodiment provides a battery pack 200 composed of battery modules from Embodiment 1 or Embodiment 2. The battery pack includes a support platform 8, a liquid cooling plate 9, an outer cover 10, a flue gas emission pipe 11, and the aforementioned multiple battery modules 100. The structure of this battery pack is basically the same as the external structure of existing battery packs. Specifically:

[0089] Multiple battery modules 100 are installed side by side on the support platform 8, and a liquid cooling plate 9 is provided between the bottom surface of the multiple battery modules 100 and the support platform; in order to ensure that the battery modules 100 and the liquid cooling plate 9 are kept insulated, an insulating layer needs to be provided between the bottom surface of the multiple battery modules 100 and the liquid cooling plate 9.

[0090] The outer cover 10 includes a top plate 101 and four side plates 102; the bottom surfaces of the four side plates 102 of the outer cover 10 are provided with folded edges, which are fixed to the support platform 8 by means of screws, and multiple battery modules 100 are located inside the outer cover.

[0091] One of the side panels 102 integrates a BMS slave unit 103, a fire alarm interface 104, a liquid cooling medium interface 105, and an electrical signal interface 106.

[0092] BMS slave 103 is used to collect voltage and temperature information of each individual cell and upload it to the BMS host;

[0093] The smoke outlet of the explosion relief pipe in each battery module 100 is connected to the smoke emission pipe 11. The smoke emission pipe 11 is connected to the fire interface 104 on the side plate of the outer cover 10. When thermal runaway occurs, the thermal runaway smoke in the individual battery is discharged from the battery pack in an orderly manner through the individual battery explosion relief port, the second through hole, the first through hole, the explosion relief pipe, the smoke emission pipe and the fire interface for subsequent processing.

[0094] The liquid cooling plate 9 is connected to the liquid cooling medium interface 105 via a water pipe. There are two liquid cooling medium interfaces 105, one as the medium inlet and the other as the medium outlet.

Claims

1. A battery module comprising N individual cells arranged along the thickness direction of each individual cell, wherein the first and last two individual cells are each provided with a clamping plate and are bound together by steel strips to form a battery string; characterized in that: It also includes a vent pipe fixed to the battery string; The bottom surface of the explosion relief pipe has N first through holes; A thermal expansion body is installed between the top surface of the battery string and the bottom surface of the explosion relief pipe; the thermal expansion body is provided with N second through holes that correspond one-to-one with the N first through holes and are kept in communication; the thermal expansion body expands when the battery heats up, so that the bottom surface of the explosion relief pipe and the thermal expansion body, as well as the thermal expansion body and the top surface of each individual battery cell, are in close contact, ensuring that the thermal runaway smoke can only be discharged from the smoke outlet of the explosion relief pipe.

2. The battery module according to claim 1, characterized in that, The thermal expansion body is a long strip of gasket. The size of the long strip of gasket is adapted to the bottom size of the explosion relief pipe. N second through holes are opened on the long strip of gasket. The N second through holes correspond one-to-one with the N first through holes and are interconnected.

3. The battery module according to claim 1, characterized in that, The thermal expansion body consists of N annular gaskets. An annular gasket is placed between the top surface of each individual cell and the bottom surface of the explosion vent. The area enclosed by the annular gaskets must completely cover the explosion vent of the individual cell when projected onto the top surface of the individual cell.

4. The battery module according to claim 3, characterized in that, The bottom surface of the explosion relief tube has N grooves, and each groove is fitted with an annular gasket; or each individual battery cell has a groove on its top surface, and each groove is fitted with an annular gasket.

5. The battery module according to claim 4, characterized in that: It also includes a long strip of flame-retardant rubber sheet; the long strip of flame-retardant rubber sheet is provided with N positioning holes, and each positioning hole is fitted with an annular gasket.

6. The battery module according to any one of claims 1 to 5, characterized in that, The explosion relief pipe is made of metal and includes a pipe body and connecting bodies on both sides in the width direction of the pipe body. At least one reinforcing rib is provided inside the pipe body, and N first through holes are provided on the bottom surface of the pipe body. The connecting bodies on both sides are used to fix the pipe body to the clamping plates at both ends by screw connection.

7. The battery module according to claim 6, characterized in that: It also includes a locking nut and a partition; the top of the partition is provided with two studs spaced apart; The separator is clamped and fixed between adjacent individual cells, and two studs pass through the mounting holes of the connectors on both sides. Locking nuts are tightened on the studs at the mounting holes.

8. The battery module according to claim 7, characterized in that: Two limiting plates are also provided at the bottom of the separator; both limiting plates are perpendicular to the main body of the separator and parallel to the lower cover of the individual battery. The two limiting plates extend to different sides of the main body of the separator and limit the lower cover of the individual battery on the adjacent sides.

9. A battery pack, characterized in that, It includes a support platform, a liquid cooling plate, an outer cover, a flue gas emission pipe, and multiple battery modules as described in any one of claims 1 to 8; Multiple battery modules are installed side by side on a support platform, and a liquid cooling plate is installed between the bottom of the multiple battery modules and the support platform; The smoke outlet of the explosion relief pipe in each battery module is connected to the flue gas emission pipe; The outer cover includes a top plate and four side plates; the four side plates of the outer cover are fixed to a support platform, and multiple battery modules are located inside the outer cover. One of the side panels integrates the BMS slave unit, fire alarm interface, liquid cooling medium interface, and electrical signal interface.

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