CN219873994U

CN219873994U - Battery pack

Info

Publication number: CN219873994U
Application number: CN202320692431.3U
Authority: CN
Inventors: 李坤; 雷政军; 强健; 韩晓宇
Original assignee: Shaanxi Olympus Power Energy Co Ltd
Current assignee: Shaanxi Olympus Power Energy Co Ltd
Priority date: 2023-04-01
Filing date: 2023-04-01
Publication date: 2023-10-20
Anticipated expiration: 2033-04-01

Abstract

The utility model belongs to the field of batteries, in particular to a battery pack, which solves the problems of limited capacity upper limit and cycle times and lower safety performance of the battery pack caused by the difference of the performances of all single batteries in the conventional battery pack. Comprises a battery pack main body formed by a plurality of unit batteries connected in parallel, a sharing pipe, a liquid storage bin and a gas communicating pipe; the sharing pipe is fixed at the bottom of the battery pack main body and is used for communicating all the inner cavities of the plurality of single batteries; the liquid storage bin is used for storing electrolyte and is communicated with the inner cavities of the plurality of single batteries through the sharing pipe; the gas communicating pipe comprises a main pipeline, a plurality of first branch pipes and at least one second branch pipe, wherein the first branch pipes and the at least one second branch pipe are arranged on the main pipeline, the main pipeline is positioned at the bottom of the battery pack main body, the ports of the first branch pipes respectively extend into the inner cavities of all the single batteries, and the ports of the second branch pipes extend into the inner cavities of the liquid storage bin; through the ventilation pipeline, the gas in the battery is exchanged with the liquid storage bin, so that the automatic liquid supplementing of the electrolyte is realized, and the liquid level height of the electrolyte in each single battery is kept consistent.

Description

Battery pack

Technical Field

The utility model relates to the field of batteries, in particular to a battery pack.

Background

The conventional battery pack (also referred to as a battery module or a high-capacity battery) is generally manufactured by connecting a plurality of unit batteries in parallel or in series, for example, chinese patent CN106531913B discloses a prismatic battery module, which comprises a plurality of prismatic battery units and a module frame, wherein the module frame is a housing with an open upper end, and the plurality of prismatic battery units are arranged into any series-parallel combined battery modules according to design requirements and then are fixed in the module frame. The battery pack manufactured directly in a series-parallel connection mode is often influenced by a single battery with the worst performance due to the existence of a barrel effect, so that the upper limit of the capacity and the circulation times of the whole battery pack are greatly limited.

In addition, since the performance of each single battery cannot be guaranteed to be consistent, under the same working condition of the system, the difference of the single batteries can be continuously amplified along with the increase of the circulation times, if more gas is generated in a certain single battery, the internal pressure of the single battery can be increased, so that the single battery is easily caused to generate thermal runaway, and the safety of the whole battery pack is reduced.

Disclosure of Invention

The utility model aims to provide a battery pack, which solves the problems of limited capacity upper limit and cycle times and lower safety performance of the battery pack caused by the difference of the performances of all single batteries in the conventional battery pack.

The technical scheme of the utility model is to provide a battery pack, which comprises a battery pack main body formed by a plurality of parallel single batteries, and is characterized in that: the device also comprises a sharing pipe, a liquid storage bin and a gas communicating pipe;

the sharing pipe is fixed at the bottom of the battery pack main body and is used for communicating all the inner cavities of the plurality of single batteries;

the liquid storage bin is used for storing electrolyte and is communicated with the inner cavities of the plurality of single batteries through the sharing pipe; wherein the space for containing electrolyte in the liquid storage bin is larger than the space for containing electrolyte in each single battery;

the gas communicating pipe comprises a main pipeline, a plurality of first branch pipes and at least one second branch pipe, wherein the first branch pipes and the at least one second branch pipe are arranged on the main pipeline, the main pipeline is positioned at the bottom of the battery pack main body, the ports of the first branch pipes extend into the inner cavities of all single batteries respectively, and the ports of the second branch pipes extend into the inner cavities of the liquid storage bin;

the vertical distances between the end faces of the sharing pipe and the communication ports of all the single batteries and the bottom of the battery pack main body are equal to each other and are h1, the vertical distances between the end faces of the ports of all the first branch pipes and the bottom of the battery pack main body are equal to each other and are h2, and the vertical distance between the end faces of the ports of the second branch pipes and the bottom of the battery pack main body is h3, wherein h1 is more than or equal to 0 and less than h2 and less than h3.

Further, in order to reduce the volume of the battery pack and improve the energy density, the main pipeline of the gas communicating pipe is sleeved in the sharing pipe, and a gap for supplying the electrolyte is arranged between the outer wall of the main pipeline and the inner wall of the sharing pipe; the port of each first branch pipe of the gas communicating pipe penetrates through the single battery shell and stretches into the inner cavity of each single battery, and the port of each second branch pipe of the gas communicating pipe penetrates through the liquid storage bin shell and stretches into the inner cavity of the liquid storage bin.

Further, in order to prevent solid impurities in the electrolyte from clogging the first branch pipes, the portions of the respective first branch pipes of the gas communication tube extending into the inner cavities of the respective unit cells are bent so that the ports of the respective first branch pipes face the bottom of the battery pack body.

Further, in order to further improve the cycle performance of the battery pack, the safety of the battery pack is improved, a liquid injection port is formed in the top of the liquid storage bin, and a pressure release valve is further arranged in the top of the liquid storage bin.

Further, the gas communicating tube may be located outside the sharing tube, and fixed at the bottom of the battery pack main body, where the bottom of the battery pack main body is provided with fifth through holes corresponding to the first branch tubes one by one, and the bottom of the liquid storage bin is provided with sixth through holes corresponding to the second branch tubes; the port of each first branch pipe of the gas communicating pipe penetrates through the fifth through hole at the bottom of the battery pack main body and stretches into the inner cavity of each single battery, and the port of each second branch pipe of the gas communicating pipe penetrates through the sixth through hole at the bottom of the liquid storage bin and stretches into the inner cavity of the liquid storage bin.

Further, in order to prevent solid impurities and the like in the electrolyte from blocking the ports of the respective first branch pipes, the portions of the respective first branch pipes extending into the inner cavities of the respective unit cells of the gas communication tube are bent so that the ports of the respective first branch pipes face the bottom of the battery body.

Further, a partition board is arranged in each single battery inner cavity, and the single battery inner cavity is divided into a first cavity and a second cavity along the width direction of the single battery; a communication groove is formed in the partition plate and is used for communicating the first chamber with the second chamber; the fifth through holes are positioned at the bottom of the first chamber, and the ports of the first branch pipes of the gas communicating pipe penetrate through the fifth through holes and are positioned in the first chamber; the second chamber is used for placing the battery cell. The battery cell is separated from the first branch pipe by the partition board so as to prevent the first branch pipe from being extruded or the battery cell residues from blocking the first branch pipe.

Further, the communication groove is positioned at the bottom of the partition plate.

Further, a liquid injection port is formed in the top of the liquid storage bin, and a pressure release valve is further arranged at the top of the liquid storage bin.

Further, in order to facilitate the installation of the gas communication tube, the main pipeline of the gas communication tube comprises a plurality of three-way pipes and a plurality of ventilation sub-pipelines, and every two ventilation sub-pipelines are connected through one three-way pipe to form the main pipeline; positioning bosses are arranged on the outer walls of the first branch pipe and the second branch pipe, and external threads are arranged on the outer walls of the first branch pipe extending out of the lower cover plate of the single battery; the outer wall of the second branch pipe extending out of the lower cover plate of the liquid storage bin is provided with external threads; the thread sections of the first branch pipe and the second branch pipe are connected with the vertical ports of the three-way pipe.

The beneficial effects of the utility model are as follows:

1. according to the battery pack provided by the utility model, the sharing pipe and the gas communicating pipe are additionally arranged, so that the electrolyte of each single battery is shared to ensure the consistency of each single battery, namely, the electrolyte cavities of all single batteries are communicated, so that the electrolytes of all single batteries are in the same system, the difference between the initial capacities of all single batteries is reduced, the consistency of all single batteries is improved to a certain extent, and the cycle life of a large-capacity battery is prolonged to a certain extent. Meanwhile, the gas communicating pipe can realize the exchange of the gas inside each single battery and the liquid storage bin, so that the automatic liquid supplementing of the electrolyte is realized, the liquid level height of the electrolyte in each single battery is kept consistent in the working process, the difference between the capacities of the single batteries in the working process is reduced, the consistency between the single batteries is further improved, and the cycle life of the high-capacity battery is further prolonged.

2. The battery pack is provided with the liquid storage bin, and the liquid storage bin can be used for filling electrolyte into the shared electrolyte system of the battery pack, so that the electrolyte of the battery pack is always kept in a proper range, the performance of the battery pack is further improved, and the influence of too little electrolyte amount on the performance of a high-capacity battery is avoided.

3. Compared with a battery pack in which an exhaust pipe or the sharing pipe is respectively arranged at the top and the bottom of a battery pack main body, the battery pack has smaller volume and higher energy density, and the utility model communicates the gas communicating pipe with the liquid storage bin, so that the electrolysis liquid in the liquid storage bin can be hydraulically returned to the inner cavity of each single battery based on the gas exhausted from the inside of the battery, and the functions of automatic liquid injection and keeping the liquid level height of the electrolyte in each single battery consistent are realized.

4. According to the utility model, the liquid injection hole is arranged in the liquid storage bin, so that firstly, electrolyte can be injected into the battery pack to form a shared electrolyte system when the battery pack is manufactured, and secondly, the electrolyte of the shared electrolyte system can be replaced at regular time after the battery pack operates for a certain cycle number, so that the cycle performance of the battery pack is further improved.

5. The battery pack provided by the utility model can also exhaust through the pressure release valve of the liquid storage bin in the use process, so that a series of problems affecting the comprehensive performance of the battery pack, such as swelling of the battery shell and the like, caused by incapability of exhausting gas are avoided.

6. The utility model can also arrange the gas communicating pipe outside the sharing pipe, and compared with the scheme of arranging the gas communicating pipe inside the sharing pipe, the utility model has simpler and more convenient installation.

Drawings

Fig. 1 is a schematic view of the structure of a battery pack of embodiment 1;

fig. 2 is a schematic structural diagram of a single cell of embodiment 1;

FIG. 3 is a schematic view of the reservoir of example 1;

FIG. 4 is a schematic view showing the structure of a gas communication tube according to embodiment 1;

fig. 5 is a schematic view showing the structure of a section (in the width direction of the battery pack) of the battery pack of example 1;

fig. 6 is a partial enlarged view of a cross section (in the width direction of the battery pack) of the battery pack of example 1;

fig. 7 is a schematic view showing the structure of a section (along the length direction of the battery pack) of the battery pack of example 1;

fig. 8 is a partial enlarged view of a section (in the length direction of the battery pack) of the battery pack of example 1;

fig. 9 is a schematic view of a structure of a battery pack of embodiment 1;

fig. 10 is another schematic structure of the battery pack of embodiment 1;

fig. 11 is an initial state diagram of the battery pack of example 1;

fig. 12 is a balance state diagram of the battery pack of example 1;

fig. 13 is a state diagram of electrolyte loss of the battery pack of example 1;

fig. 14 is a state diagram of the battery pack of example 1 after automatic electrolyte replenishment;

fig. 15 is a schematic view of the structure of a battery pack of embodiment 2;

fig. 16 is a schematic structural view of a lower cover plate of a single battery in embodiment 2;

fig. 17 is a schematic view showing the structure of a cross section (in the width direction of the battery pack) of the battery pack of example 2;

FIG. 18 is a schematic view of the structure of a barrel according to embodiment 2;

FIG. 19 is a schematic view of another view of the barrel of embodiment 2;

fig. 20 is a schematic view showing the structure of a section (along the length direction of the battery pack) of the battery pack of example 2;

FIG. 21 is a schematic view showing the structure of a gas communication tube according to embodiment 2;

the reference numerals in the drawings are:

1. a single battery; 11. a lower cover plate; 12. a first through hole; 13. a fifth through hole; 14. a partition plate; 141. a through groove; 2. a liquid storage bin; 21. a liquid injection port; 22. a pressure release valve; 23. a second through hole; 24. a sixth through hole; 3. sharing the tube; 31. explosion venting mechanism; 32. a plug; 4. a gas communicating tube; 41. a main pipeline; 411. a three-way pipe; 412. a ventilation sub-line; 413. positioning the boss; 414. locking the nut; 415. a movable joint; 42. a first branch pipe; 43. and a second branch pipe.

Detailed Description

So that the manner in which the above recited objects, features and advantages of the present utility model can be understood in detail, a more particular description of the utility model, briefly summarized above, may be had by reference to the embodiments, some of which are illustrated in the appended drawings.

The appearances of the phrase "in other embodiments" in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments.

Also in the description of the present utility model, it should be noted that the azimuth or positional relationship indicated by "top, bottom" or the like in terms are based on the azimuth or positional relationship shown in the drawings, and are merely for convenience of describing the present utility model and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific azimuth, be constructed and operated in a specific azimuth, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first or second" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

The existing battery pack (also called as a battery module or a high-capacity battery) comprises a battery pack main body formed by connecting a plurality of single batteries in parallel and a shared pipeline assembly positioned at the bottom of the battery pack main body; and the shared pipeline component is used for completely penetrating the inner cavities of the plurality of single batteries so that all the single batteries in the battery pack are in an electrolyte system. The battery pack can strengthen the uniformity of electrolyte of each single battery in the battery pack through the shared pipeline assembly, so that the cycle life is prolonged, but the problem that the comprehensive performance of the battery pack is reduced because generated gas cannot be discharged in time still exists in the use process of the battery pack, meanwhile, the gas yield of each single battery is different or the electrolyte consumption is different to cause the difference of the liquid level in each single battery due to the fact that the single batteries still have some differences, the battery pack can be influenced by one single battery with the worst performance due to the existence of a barrel effect, and the upper limit of the capacity and the cycle times of the whole large-capacity battery are extremely limited.

In addition, there is a battery pack (also called a battery module or a high-capacity battery) at present, which comprises a battery pack main body formed by connecting a plurality of single batteries in parallel, and a shared pipeline assembly positioned at the top of the battery pack main body; and the shared pipeline component is used for completely penetrating the inner cavities of the plurality of single batteries so as to ensure that the gas paths of all the single batteries in the battery pack are communicated, and redundant gas can be discharged through the shared pipeline component. The battery pack can exhaust gas through the shared pipeline assembly, but the gas yield of each single battery is different or the electrolyte consumption is different, so that the liquid level in each single battery is different, the battery pack can be influenced by one single battery with the worst performance due to the existence of a wooden barrel effect, and the upper limit of the capacity and the circulation times of the whole large-capacity battery are greatly limited.

In order to overcome the problems, the utility model provides a battery pack, which comprises a battery pack main body formed by a plurality of unit cells connected in parallel, a sharing pipe, a liquid storage bin and a gas communicating pipe; the sharing pipe is fixed at the bottom of the battery pack main body and is used for communicating all the inner cavities of the plurality of single batteries; the liquid storage bin is used for storing electrolyte and is communicated with the inner cavities of the plurality of single batteries through the sharing pipe; wherein the space for containing electrolyte in the liquid storage bin is larger than the space for containing electrolyte in each single battery; the gas communicating pipe comprises a main pipeline, a plurality of first branch pipes and at least one second branch pipe, wherein the first branch pipes and the at least one second branch pipe are arranged on the main pipeline, the main pipeline is positioned at the bottom of the battery pack main body, the ports of the first branch pipes respectively extend into the inner cavities of the single batteries, and the ports of the second branch pipes extend into the inner cavities of the liquid storage bin;

The vertical distances between the end faces of the sharing pipe and the communication ports of all the single batteries and the bottom of the battery pack main body are equal to each other and are h1, the vertical distances between the end faces of the ports of all the first branch pipes and the bottom of the battery pack main body are equal to each other and are h2, and the vertical distance between the end faces of the ports of the second branch pipes and the bottom of the battery pack main body is h3, wherein h1 is more than or equal to 0 and less than h2 and less than h3. It should be noted here that the lower cover plates of the individual battery cells forming the bottom of the battery pack body are all located at the same horizontal plane. According to the utility model, the sharing pipe and the gas communicating pipe are additionally arranged, so that the electrolyte of each single battery is shared to ensure the consistency of each single battery, namely, the electrolyte cavities of all single batteries are communicated, so that the electrolytes of all single batteries are in the same system, the difference between the initial capacities of all single batteries is reduced, the consistency of all single batteries is improved to a certain extent, and the cycle life of a large-capacity battery is prolonged to a certain extent. Meanwhile, the gas communicating pipe can realize the exchange of the gas inside each single battery and the liquid storage bin, so that the automatic liquid supplementing of the electrolyte is realized, the liquid level height of the electrolyte in each single battery is kept consistent in the working process, the difference between the capacities of the single batteries in the working process is reduced, the consistency between the single batteries is further improved, and the cycle life of the high-capacity battery is further prolonged.

The utility model is further described with reference to the drawings and specific examples.

Example 1

As shown in fig. 1 to 5, the battery pack of the present embodiment includes 9 unit cells 1, a sharing tube 3, 1 liquid storage bin 2, and a gas communication tube 4; the 9 unit cells 1 are connected in parallel to form a battery pack body. The single battery 1 can be a single square shell battery and comprises an upper cover plate, a lower cover plate 11, a cylinder body and an electric core; the battery cell can also be called an electrode assembly, and is formed by sequentially arranging a positive electrode, a diaphragm and a negative electrode and adopting lamination or winding technology. As shown in fig. 2, the upper cover plate, the cylinder body and the lower cover plate 11 form a battery case, the battery cell is arranged in the battery case, and electrolyte is injected into the battery case. Wherein, be provided with first through-hole 12 on the lower apron 11 of each battery case, each first through-hole 12 all with sharing pipe 3 sealed intercommunication for the electrolyte of each battery cell 1 realizes sharing. One end of the sharing pipe 3 is provided with an explosion venting mechanism 31, and the other end is plugged by a plug 32.

As shown in fig. 3, the liquid storage bin 2 is a sealed cavity formed by an upper cover plate, a cylinder body and a lower cover plate 11, and is used for storing electrolyte, the lower cover plate 11 of the liquid storage bin 2 is provided with a second through hole 23, the second through hole 23 is in sealed communication with the sharing pipe 3, and the specific communication mode can adopt a mode that the single battery 1 is communicated with the sharing pipe 3, so that the inner cavity of the liquid storage bin 2 is communicated with the inner cavity of each single battery 1, and further, the electrolyte in the liquid storage bin 2 can be ensured to flow into the shells of each single battery 1 under different pressure differences, and the electrolyte in the shells of each single battery 1 can also flow into the liquid storage bin 2, thereby realizing liquid injection and liquid exchange. The upper cover plate of the liquid storage bin 2 is provided with a liquid injection port 21, and electrolyte can be injected into the liquid storage bin 2 based on the liquid injection port 21. In addition, in order to prevent the pressure of the liquid storage bin 2 from being too high, a pressure release valve 22 is further arranged on the upper cover plate of the liquid storage bin 2, the pressure release valve 22 is preferably a one-way valve, and when the gas pressure in the liquid storage bin 2 exceeds P1, the one-way valve is opened to discharge the high-pressure gas in the liquid storage bin 2. The arrangement of the one-way valve can ensure that the inner cavity pressure of the liquid storage bin 2 is always below P1, and the safety of the liquid storage bin 2 and the whole battery pack is ensured. The above P1 is determined according to the material and thickness of the shell of the liquid storage bin 2.

The present embodiment further includes a gas communication tube 4, as shown in fig. 4 to 8, the gas communication tube 4 including a main line 41, and 9 first branch pipes 42 and 1 second branch pipe 43 provided on the main line 41, as can be seen from the figure, the main line 41 is a straight pipe, fitted inside the sharing tube 3, and a gap for the circulation of an electrolyte is provided between an outer wall of the main line 41 and an inner wall of the sharing tube 3; the first branch pipes 42 and the second branch pipes 43 are disposed perpendicular to the main pipe 41, and the first branch pipes 42 are identical in height, and the second branch pipes 43 are higher than the first branch pipes 42. The port of each first branch pipe 42 extends into the inner cavity of each single battery 1, and the port of each second branch pipe 43 extends into the inner cavity of the liquid storage bin 2.

In order to prevent the ports of the first branch pipes 42 from being blocked by impurities or the like, the first branch pipes may be bent so that the ports thereof are downward (the impurities fall to the bottom due to gravity).

The structure of the sharing tube 3 and the gas communication tube 4 and the assembly method of the sharing tube 3 and the gas communication tube 4, the unit cell 1 and the liquid storage bin 2 may include the following modes:

(1) The shared pipe 3 has the structure that: comprises a whole shared main pipe and 10 third branch pipes arranged on the shared main pipe;

The gas communication tube 4 may take the following structural form:

the main line 41 of the gas communication tube 4 is an entire line, and 9 third through holes, which are in one-to-one correspondence with the first branch pipe 42 and the 1 second branch pipe 43, are formed in the main line 41.

When assembling, the main pipe 41 of the gas communication pipe 4 is first sleeved and fixed in the shared main pipe of the shared pipe 3, and at this time, it is necessary to ensure that each third through hole on the main pipe 41 of the gas communication pipe 4 corresponds to and is coaxial with 10 third branch pipes on the shared main pipe one by one; and then, the first branch pipe 42 and the second branch pipe 43 of the gas communicating pipe 4 are sleeved in the third branch pipes on the shared main pipe, the first branch pipe 42 and the second branch pipe 43 of the gas communicating pipe 4 are connected with the corresponding third through holes one by one in a welding, threaded connection or interference fit mode, and when the threaded connection or interference fit connection mode is adopted, in order to ensure the tightness of the connection parts of the first branch pipe 42, the second branch pipe 43 and the third through holes, the main pipeline 41 can adopt square pipes, the first branch pipe 42 and the second branch pipe 43 are circular pipes, and the corresponding third through holes are circular holes. In addition, when the screw connection is adopted, a sealing gasket can be additionally arranged at the screw connection part. And then the 9 third branch pipes on the shared main pipe are connected with the first through holes 12 of the lower cover plate 11 one by one, and the other third branch pipe is connected with the second through hole 23 of the lower cover plate of the liquid storage bin 2, and the connection can be particularly realized by adopting a welding, threaded connection or direct extrusion interference fit mode.

When the first branch pipe 42, the second branch pipe 43 and the third through hole are connected by welding, high reliability of the connection part can be ensured, but the whole welding process and the welding process are complex, and the relative cost is high.

When the first branch pipe 42, the second branch pipe 43 and the third through-hole are connected by screw, a gasket may be added at the connection portion, which is advantageous in that the connection cost is low, and screw connection is one of the most common sealing connection methods, but since the gas communication tube 4 is immersed in the electrolyte for a long time, the reliability of the screw connection is questionable after a long time of use.

When the first branch pipe 42, the second branch pipe 43 and the third through hole are connected in an interference fit mode, the sealing connection is realized in an extrusion mode, so that the cost is lower relative to welding, and the air tightness is better after long-term use relative to threaded connection.

When the third branch pipe on the shared main pipe is connected with the first through hole 12 of the lower cover plate 11 of the single battery 1 or the second through hole 23 of the lower cover plate of the liquid storage bin 2 in a welding mode, high reliability of the connection part can be ensured, but the whole welding process and the welding process are complex, and the relative cost is high.

When the third branch pipe on the shared main pipe is in threaded connection with the first through hole 12 of the lower cover plate 11 of the single battery 1 or the second through hole 23 of the lower cover plate of the liquid storage bin 2, a sealing gasket can be additionally arranged at the connection part, and the mode has the advantages of lower connection cost, threaded connection is the most common sealing connection mode, but after long-time use, the airtight reliability of the threaded connection is doubtful.

When the third branch pipe on the shared main pipe is connected with the first through hole 12 of the lower cover plate 11 of the single battery 1 or the second through hole 23 of the lower cover plate of the liquid storage bin 2 in an interference fit mode, the cost is lower than that of welding, and the air tightness is better after long-term use than that of threaded connection. However, the connection method has high requirements on the assembly of each single battery 1 and the processing precision of the first through hole 12 of the lower cover plate 11, and when the first through hole 12 of one single battery 1 and the first through holes 12 of other single batteries 1 cannot be guaranteed to be collinear and coplanar, the problem that the third branch pipe cannot be connected with the first through hole 12 may be caused when the connection is extruded.

(2) The shared pipe 3 is a whole pipe, and is provided with fourth through holes which are in one-to-one correspondence with the first through holes 12 of the lower cover plate 11; at this time, a fourth branch pipe is integrally provided at the position of the first through hole 12 on the lower cover plate 11 of each unit cell 1;

the gas communication tube 4 may take the following structural form:

the main pipeline 41 of the gas communicating pipe 4 is a whole pipeline, and 9 third through holes which are in one-to-one correspondence with the first branch pipe 42 and the 1 second branch pipe 43 are formed in the main pipeline 41;

when assembling, the main pipe 41 of the gas communication pipe 4 is first sleeved and fixed in the sharing pipe 3, and at this time, it is necessary to ensure that each third through hole on the main pipe 41 of the gas communication pipe 4 corresponds to and is coaxial with 10 fourth through holes on the sharing main pipe one by one; then, one end of each of the first branch pipe 42 and the second branch pipe 43 of the gas communication pipe 4 is fixed at the third through hole position of the main pipeline 41 through a welding, threaded or interference fit connection mode after passing through the corresponding fourth through hole on the shared pipe 3; when the connection mode of threaded connection or interference fit is adopted, in order to ensure the tightness of the connection parts of the first branch pipe 42, the second branch pipe 43 and the third through hole, the main pipeline 41 can adopt square pipes, the first branch pipe 42 and the second branch pipe 43 are round pipes, and the corresponding third through hole is also a round hole. In addition, when the screw connection is adopted, a sealing gasket can be additionally arranged at the screw connection part. Then, extruding the fourth branch pipes at the positions of the first through holes 12 on the lower cover plate 11 of each battery shell into each fourth through hole of the sharing pipe 3 in an interference fit mode; in order to ensure the tightness of the connection part, the sharing pipe 3 can be a square pipe, the fourth branch pipe is a round pipe, and the corresponding fourth through hole is a round hole. At this time, 9 first branch pipes 42 and 1 second branch pipe 43 are respectively sleeved in the fourth branch pipe.

When the fourth branch pipe on the lower cover plate 11 is connected with each fourth through hole of the sharing pipe 3 in a welding manner, high reliability of the connection part can be ensured, but the whole welding process and the welding process are complex, and the relative cost is high.

When the fourth branch pipe on the lower cover plate 11 is connected with each fourth through hole of the sharing pipe 3 through threads, a sealing gasket can be additionally arranged at the connecting part, and the mode has the advantages of lower connecting cost, the threaded connection is the most common sealing connection mode, but after the threaded connection is used for a long time, the airtight reliability of the threaded connection is doubtful.

When the fourth branch pipe on the lower cover plate 11 is connected with each fourth through hole of the sharing pipe 3 in an interference fit mode, the cost is lower than that of welding, and the air tightness is better after long-term use than that of threaded connection. However, the connection method has high requirements on the assembly of each single battery 1 and the processing precision of the fourth branch pipe of the lower cover plate 11, and when the fourth branch pipe of one single battery 1 and the fourth branch pipe of other single batteries 1 cannot ensure collineation and coplanarity, the problem that the fourth through hole and the fourth branch pipe cannot be connected may be caused when the connection is extruded.

(3) The shared pipe 3 has the structure that: is formed by directly sealing and splicing a plurality of sections of sub-pipelines in interference fit; at this time, the multiple sections of sub-pipelines are arranged on the lower cover plate 11 of the single battery 1 one by one, are integrally extruded with the lower cover plate 11, and are communicated with the first through hole 12 of the lower cover plate 11.

The gas communication tube 4 may take the following structural form:

During assembly, the sharing pipe 3 is extruded at first, two ends of the sub-pipe are used as connecting ends of the other sub-pipe, when the two single batteries 1 are connected in an extrusion mode, one end of the sub-pipe on one single battery 1 is extruded into the sub-pipe of the other single battery 1, interference fit is achieved between the two ends, and tightness after extrusion is achieved is guaranteed. After the sharing tube 3 is connected by extrusion, note that the battery cell is not yet installed in the battery case, and the upper cover plate of the battery case is not yet welded, so that the cylinder and the lower cover plate can be welded incompletely at this time, the main tube 41 of the gas communication tube 4 is sleeved inside the sharing tube 3, and then each of the first branch tube 42 and the second branch tube 43 is directly inserted into each of the third through holes of the main tube 41 of the gas communication tube 4 from the first through hole 12 and the second through hole 23 in one-to-one correspondence, and the connection modes of the first branch tube 42, the second branch tube 43 and the third through hole are interference fit, or can be welded or screwed. When the connection mode of threaded connection or interference fit is adopted, in order to ensure the tightness of the connection parts of the first branch pipe 42, the second branch pipe 43 and the third through hole, the main pipeline 41 can adopt square pipes, the first branch pipe 42 and the second branch pipe 43 are round pipes, and the corresponding third through hole is also a round hole. In addition, when the screw connection is adopted, a sealing gasket can be additionally arranged at the screw connection part. And then the cylinder body and the lower cover plate are welded, and the upper cover plate is welded at the upper end of the cylinder body after the battery cell is arranged.

When the sharing pipe 3 is extruded, as the sub-pipelines of the sharing pipe 3 are directly arranged on the lower cover plate 11 of the single battery 1 and are in extrusion connection, the requirement on processing precision is extremely high, if the sub-pipelines of two adjacent single batteries 1 cannot ensure collineation and coplanarity, the sub-pipelines can possibly displace relative to the lower cover plate 11 or the lower cover plate 11 displaces relative to the shell during extrusion connection, and further the battery is damaged; therefore, this method is relatively simplified in process steps but requires high precision.

(4) The shared pipe 3 has the structure that: the sealing plug is formed by directly carrying out sealing plug connection on the multi-section sub-pipelines and the intermediate connecting pipes in interference fit; the multi-section sub-pipelines are arranged on the lower cover plate 11 of the single battery 1 one by one, are integrally extruded with the lower cover plate 11, and are communicated with the first through hole 12 of the lower cover plate 11; adjacent sub-pipelines are connected through an intermediate connecting pipe; the middle connecting pipe is connected with each sub-pipeline in an interference fit mode.

The gas communication tube 4 may take the following structural form:

the main pipeline 41 of the gas communicating pipe 4 is a whole pipeline, and 9 third through holes which are in one-to-one correspondence with the first branch pipe 42 and the 1 second branch pipe 43 are formed in the main pipeline 41; at this time, for the subsequent assembly, the tightness of the connection parts of the first branch pipe 42, the second branch pipe 43 and the third through holes is achieved, the main pipeline can be square pipes, the first branch pipe 42 and the second branch pipe 43 are round pipes, and the corresponding third through holes are round holes.

During assembly, the sharing pipe 3 is extruded firstly, two ends of the sub-pipe are used as the connecting ends of the middle connecting pipe, and when the two single batteries 1 are connected in an extrusion mode, one end of the sub-pipe on one single battery 1 is extruded into one end of the middle connecting pipe, and one end of the sub-pipe on the other single battery 1 is extruded into the other end of the middle connecting pipe.

After the sharing tube 3 is connected by extrusion, note that the battery core is not yet installed in the battery case, and the upper cover plate of the battery case is not yet welded, so that in order to facilitate connection between the first branch tube 42, the second branch tube 43 and the third through hole, the cylinder body and the lower cover plate may not be welded first, the main tube 41 of the gas communicating tube 4 is sleeved inside the sharing tube 3, and then each of the first branch tube 42 and the second branch tube 43 is directly inserted into each of the third through holes of the main tube 41 of the gas communicating tube 4 from the first through hole 12 and the second through hole 23 in one-to-one correspondence, and the first branch tube 42 and the second branch tube 43 may be connected by interference fit, or may be connected by welding or threaded connection. And then the cylinder body and the lower cover plate are welded, and the upper cover plate is welded at the upper end of the cylinder body after the battery cell is arranged.

With this structure, when the shared pipe 3 is extruded, an error caused by processing can be shared to the intermediate connection pipe, and the requirement for processing accuracy is reduced.

Based on the above analysis, the present embodiment preferably has the structure of the shared tube 3 and the gas communication tube 4, and the assembly of the shared tube 3 and the gas communication tube 4 with the unit cell 1 and the reservoir 2 is as follows:

the shared pipe 3 has the structure that: the sealing plug is formed by directly carrying out sealing plug connection on the multi-section sub-pipelines and the intermediate connecting pipes in interference fit; the multi-section sub-pipelines are arranged on the lower cover plate 11 of the single battery 1 one by one, are integrally extruded with the lower cover plate 11, and are communicated with the first through hole 12 of the lower cover plate 11; adjacent sub-pipelines are connected through an intermediate connecting pipe; the middle connecting pipe is connected with each sub-pipeline in an interference fit mode.

The gas communication tube 4 has the structure: the main pipeline 41 of the gas communicating pipe 4 is a whole pipeline, and 9 third through holes which are in one-to-one correspondence with the first branch pipe 42 and the 1 second branch pipe 43 are formed in the main pipeline 41; the main pipeline is square pipe, and first branch pipe 42, second branch pipe 43 select for use the pipe, and corresponding third through-hole is the round hole.

During assembly, the sharing pipe 3 is extruded firstly, two ends of the sub-pipe are used as the connecting ends of the middle connecting pipe, and when the two single batteries 1 are connected in an extrusion mode, one end of the sub-pipe on one single battery 1 is extruded into one end of the middle connecting pipe, and one end of the sub-pipe on the other single battery 1 is extruded into the other end of the middle connecting pipe. After the sharing tube 3 is extruded and connected, the main pipeline 41 of the gas communicating tube 4 is sleeved into the sharing tube 3, and then each of the first branch pipes 42 and the second branch pipes 43 are directly inserted into each of the third through holes of the main pipeline 41 of the gas communicating tube 4 from the first through holes 12 of the lower cover plate 11 in one-to-one correspondence, and are connected in an interference fit mode. And finally, welding the cylinder body with the lower cover plate, and then, placing the battery cells in the single batteries 1, and welding the upper cover plate to complete the assembly.

In order to realize automatic electrolyte replenishing and maintain the consistency of the electrolyte liquid level in each single battery 1, the height of each first branch pipe 42 extending into the inner cavity of the single battery 1 and the height of each second branch pipe 43 extending into the liquid storage bin 2 need to satisfy the following relationship:

for convenience of description, it may be defined that the vertical distances between the end faces of the communication ports of the sharing tube 3 and the respective unit cells 1 and the bottom of the battery pack main body (which may be understood as the lower cover plate 11 of the unit cell 1) are equal to each other and are all h1, the vertical distances between the end faces of the ports of all the first branch tubes 42 and the bottom of the battery pack main body are equal to each other and are all h2, the vertical distances between the end faces of the ports of the second branch tubes 43 and the bottom of the battery pack main body are h3, and h1, h2, h3 are required to satisfy: h1 is more than or equal to 0 and less than h2 is more than or equal to 0 and less than h3. Wherein fig. 9 is a structure in which h1 is equal to 0, and fig. 10 is a structure in which h1 is greater than 0.

After the battery pack is assembled, the battery pack and the liquid storage bin 2 are vacuumized, and electrolyte is filled into the battery pack and the liquid storage bin 2 through a liquid filling port 21 of the liquid storage bin 2, as shown in fig. 11. When the filling level of the electrolyte in each unit cell 1 exceeds the port of each first branch tube 42 of the gas communication tube 4 in the unit cell 1, the electrolyte forms a liquid seal with the gas communication tube 4 of the unit cell 1, and when the electrolyte is filled to about 5CM below the port of the second branch tube 43 in the reservoir 2, the filling of the electrolyte is stopped, as shown in fig. 12. Since the liquid storage bin 2 is communicated with the electrolyte in each single battery 1, the liquid level of the liquid storage bin 2 and the liquid level of the inner cavity of the single battery 1 can be unequal in height, but the pressure of the inner cavities of the liquid storage bin 2 and the single battery 1 is balanced and stable.

With long-term operation of the battery pack, the following two cases may occur:

when the battery pack works for a long time, gas is generated in each single battery 1 due to electrochemical action, if more gas is generated in a certain single battery 1, the internal pressure of the single battery 1 is increased, at this time, the internal pressure of the single battery 1 extrudes electrolyte in the single battery outwards, and the extruded electrolyte flows to the inner cavities of other single batteries 1 and the inner cavities of the liquid storage bin 2 through the sharing pipe 3, as shown in fig. 13. Since the gas space in the reservoir 2 is far larger than the gas space of each unit cell, most of the extruded electrolyte flows into the reservoir 2, and if the internal pressure of the unit cell 1 is continuously increased, the electrolyte above the port of the first branch pipe 42 in the unit cell gas communicating pipe 4 is all extruded, so that the port of the first branch pipe 42 is exposed, at this time, the redundant gas in the unit cell 1 enters the main pipeline 41 of the gas communicating pipe 4 through the first branch pipe 42, and then, the gas flows to other areas with smaller pressure. Since the internal air pressure of the other single batteries 1 is higher than that of the liquid storage bin 2. So that the extra gas will flush the electrolyte in the gas communicating tube 4 into the reservoir 2 and discharge the extra gas into the gas chamber above the reservoir 2. At this time, the liquid level of the liquid storage bin 2 is higher than each single battery 1, especially higher than the single battery 1 in the abnormal state. At this time, the liquid level and pressure in the liquid storage bin 2 and other single batteries 1 will flow again and match each other. Of course, the electrolyte in the reservoir 2 will flow to the abnormal cell 1. Then, as in the case of the initial filling of the electrolyte, the gas and the liquid exchange each other to reform the balance, as shown in fig. 14. The abnormal unit cell 1 is again filled with the electrolyte and forms a stable and balanced liquid seal. This process is actually that the surplus gas of the abnormal unit cell 1 is discharged to the reservoir 2. But the internal pressure of the whole system increases. When the internal pressure of the entire battery pack increases to the upper limit P1, the relief valve 22 is opened to discharge the surplus gas, thereby depressurizing the entire battery pack.

Secondly, when the battery pack works for a long time, the electrolyte in one single battery 1 may be excessively consumed or adsorbed due to various reasons, at this time, the internal pressure of the single battery 1 is reduced, the internal pressures of other single batteries 1 and the liquid storage bin 2 are reduced slowly, and at this time, the electrolyte in the other single batteries 1 and the liquid storage bin 2 can enter the inner cavity of the single battery 1 under the action of pressure until the pressure reaches balance.

Example 2

Unlike embodiment 1, in which the gas communication tube 4 is located outside the common tube 3, as shown in fig. 15, the gas communication tube 4 is fixed to the bottom of the battery pack body, the lower cover 11 of each unit cell 1 is further provided with a fifth through hole 13 corresponding to each first branch tube 42 one by one, as shown in fig. 16, and the lower cover of the liquid storage bin 2 is provided with a sixth through hole 24 corresponding to the second branch tube 43; the port of each first branch pipe 42 of the gas communicating pipe 4 passes through the fifth through hole 13 on the lower cover plate 11 of each single battery 1 and stretches into the inner cavity of each single battery 1, and the port of the second branch pipe 43 of the gas communicating pipe 4 passes through the sixth through hole 24 at the bottom of the liquid storage bin 2 and stretches into the inner cavity of the liquid storage bin 2.

As shown in fig. 17 to 19, in the present embodiment, a partition plate 14 is further provided in the inner cavity of each unit cell 1, dividing the inner cavity of the unit cell 1 into a first chamber and a second chamber in the width direction of the unit cell 1; the partition 14 is provided with a communicating groove 141 for communicating the first chamber with the second chamber, so that the electrolyte can flow between the two inner chambers conveniently. The fifth through-hole 13 is located at the bottom of the first chamber, and the port of each first branch tube 42 of the gas communication tube 4 is located in the first chamber through the fifth through-hole 13. In addition, the first branch pipes 42 are opened downward, and the clogging of the inlet of the communication pipe with impurities and the like (the impurities fall to the bottom due to gravity) is prevented.

The structure of the sharing tube 3 and the manner of assembling the sharing tube 3 with the unit cell 1 and the reservoir 2 in this embodiment are the same as those of embodiment 1, and the structure of the gas communication tube 4 and the manner of assembling the sharing tube 3 with the unit cell 1 and the reservoir 2 are as follows:

the gas communication tube 4 may take several structural forms as follows:

(1) The main pipeline 41 of the gas communicating pipe 4 is a whole pipeline, and third through holes which are in one-to-one correspondence with the first branch pipes 42 and the second branch pipes 43 are formed in the main pipeline 41;

during assembly, the shared tube 3 is assembled firstly, then each of the first branch tube 42 and the second branch tube 43 of the gas communicating tube 4 is inserted into the fifth through hole 13 of the lower cover plate 11 of each single battery 1 and the sixth through hole 24 of the lower cover plate of the liquid storage bin 2 respectively and connected and fixed, a welding, threaded connection or interference fit mode can be adopted, and then each of the first branch tube 42 and the second branch tube 43 is connected with the third through hole of the main pipeline 41 respectively, and a welding or interference fit mode can be adopted.

The first branch pipe 42 and the second branch pipe 43 of the gas communication tube 4 may be connected to the third through hole of the main tube 41, respectively, and at this time, it may be understood that the gas communication tube 4 is assembled first, and then the first branch pipe 42 and the second branch pipe 43 are inserted into the fifth through hole 13 of the lower cover plate 11 of each unit cell 1 and the sixth through hole 24 of the liquid storage bin 2, respectively, and the first branch pipe 42 and the fifth through hole 13, the second branch pipe 43 and the sixth through hole 24 may be connected by interference fit, so as to realize sealing, and the two may also be connected by welding or screwing.

When the first branch pipe 42, the second branch pipe 43, the fifth through hole 13 and the sixth through hole 24 are connected by welding, high reliability of the connection portion can be ensured.

When the first branch pipe 42, the second branch pipe 43, the fifth through-hole 13 and the sixth through-hole 24 are connected by screw, a gasket may be added at the connection portion, which has the advantage of lower connection cost, screw connection is one of the most common sealing connection methods, but since the gas communication tube 4 is immersed in the electrolyte for a long time, the airtight reliability of the screw connection is questionable after a long time of use.

When the first branch pipe 42, the second branch pipe 43, the fifth through hole 13 and the sixth through hole 24 are connected in an interference fit mode, the sealing connection is realized in an extrusion mode, so that the cost is lower compared with welding, and the air tightness is better after long-term use compared with threaded connection. However, when the lower cover plate is connected in a squeezing mode, the lower cover plate can be deformed, even the welding seam of the lower cover plate can leak, and safety accidents are caused.

(2) The structure of the gas communicating tube 4 may further include, as shown in fig. 20 to 21, a three-way tube 411 having a plurality of vertical ports with movable joints, a plurality of ventilation sub-tubes 412, a plurality of first branch tubes 42 and a second branch tube 43, wherein the vertical ports of the three-way tube 411 serve as connection ports of the first branch tube 42 or the second branch tube 43, the other two lateral ports serve as connection ends with the ventilation sub-tubes 412, positioning bosses 413 are provided on the first branch tube 42 and the second branch tube 43, external threads are provided on the outer walls of the first branch tube 42 extending out of the lower cover plate 11 of the unit cell 1, and external threads are provided on the outer walls of the second branch tube 43 extending out of the lower cover plate of the liquid storage bin 2.

During assembly, the shared pipe 3 is assembled first, then the first branch pipe 42 and the second branch pipe 43 are respectively inserted into the corresponding fifth through hole 13 and the sixth through hole 24 from the cylinder, axial positioning is realized through the positioning boss 413, and sealing gaskets can be arranged on the inner surface and the outer surface of the lower cover plate 11. Thereafter, the locking nuts 414 are screwed on the threaded sections of the first branch pipe 42 and the second branch pipe 43 extending out of the lower cover plate 11, and each of the first branch pipe 42 and the second branch pipe 43 is locked on the lower cover plate of the single battery 1 and the liquid storage bin 2 exactly and hermetically. Then, a plurality of three-way pipes 411 are utilized to reliably connect a plurality of ventilation sub-pipelines 412, and when the three-way pipes are specifically connected, two ends of each ventilation sub-pipeline 412 are respectively connected with one of the transverse ports of different three-way pipes, and a main pipeline 41 of the gas communicating pipe 4 can be formed by adopting a welding, interference fit or threaded connection mode; the tee vertical ports with the union are then locked to the threaded sections of each of the first and second branches 42, 43 based on the union (which can be understood as a nut). So that all the air paths are connected. Or a whole straight pipe with a plurality of branch pipes can be directly adopted as a main pipeline, after each first branch pipe and each second branch pipe are locked on the lower cover plate of the single battery 1 and the liquid storage bin 2, each branch pipe of the main pipeline is communicated with the first branch pipe and the second branch pipe in a sealing way. The structure is simple to assemble and easy to realize, but the machining precision requirement for each branch pipe of the main pipeline is higher.

Claims

1. A battery pack comprising a battery pack body formed of a plurality of parallel unit cells (1), characterized in that: the device also comprises a sharing pipe (3), a liquid storage bin (2) and a gas communicating pipe (4);

the sharing pipe (3) is fixed at the bottom of the battery pack main body and is used for communicating all the inner cavities of the plurality of single batteries (1);

the liquid storage bin (2) is used for storing electrolyte and is communicated with the inner cavities of the plurality of single batteries (1) through the sharing pipe (3); wherein the space for containing electrolyte in the liquid storage bin is larger than the space for containing electrolyte in each single battery;

the gas communication pipe (4) comprises a main pipeline (41), a plurality of first branch pipes (42) and at least one second branch pipe (43), wherein the first branch pipes (42) and the at least one second branch pipe (43) are arranged on the main pipeline (41), the main pipeline (41) is positioned at the bottom of the battery pack main body, the ports of the first branch pipes (42) respectively extend into the inner cavities of all the single batteries (1), and the ports of the second branch pipes (43) extend into the inner cavities of the liquid storage bin (2);

the vertical distance between the end faces of the communication ports of the sharing pipe (3) and the single batteries (1) and the bottom of the battery pack main body is equal to h1, the vertical distance between the end faces of the ports of all the first branch pipes (42) and the bottom of the battery pack main body is equal to h2, and the vertical distance between the end faces of the ports of the second branch pipes (43) and the bottom of the battery pack main body is h3, wherein h1 is more than or equal to 0 and less than h2 and less than h3.

2. The battery pack according to claim 1, wherein: a main pipeline (41) of the gas communicating pipe (4) is sleeved in the sharing pipe (3), and a gap for supplying power fluid is formed between the outer wall of the main pipeline (41) and the inner wall of the sharing pipe (3); the port of each first branch pipe (42) of the gas communicating pipe (4) penetrates through the shell of the single battery (1) to extend into the inner cavity of each single battery (1), and the port of each second branch pipe (43) of the gas communicating pipe (4) penetrates through the shell of the liquid storage bin (2) to extend into the inner cavity of the liquid storage bin (2).

3. The battery pack according to claim 2, wherein: the parts of the first branch pipes (42) of the gas communicating pipes (4) extending into the inner cavities of the single batteries (1) are bent, so that the ports of the first branch pipes (42) face the bottom of the battery pack main body.

4. A battery pack according to claim 3, wherein: the top of the liquid storage bin (2) is provided with a liquid injection port (21), and the top of the liquid storage bin (2) is also provided with a pressure release valve (22).

5. The battery pack according to claim 1, wherein: the gas communication pipe (4) is positioned outside the sharing pipe (3) and fixed at the bottom of the battery pack main body, the bottom of the battery pack main body is provided with fifth through holes (13) which are in one-to-one correspondence with the first branch pipes (42), and the bottom of the liquid storage bin (2) is provided with sixth through holes (24) which are in correspondence with the second branch pipes (43); the port of each first branch pipe (42) of the gas communicating pipe (4) penetrates through a fifth through hole (13) at the bottom of the battery pack main body and stretches into the inner cavity of each single battery (1), and the port of each second branch pipe (43) of the gas communicating pipe (4) penetrates through a sixth through hole (24) at the bottom of the liquid storage bin (2) and stretches into the inner cavity of the liquid storage bin (2).

6. The battery pack according to claim 5, wherein: the parts of the first branch pipes (42) of the gas communicating pipes (4) extending into the inner cavities of the single batteries (1) are bent, so that the ports of the first branch pipes (42) face the bottom of the battery pack main body.

7. The battery pack according to claim 5 or 6, wherein: the inner cavities of the single batteries (1) are internally provided with a baffle plate (14), and the inner cavities of the single batteries (1) are divided into a first cavity and a second cavity along the width direction of the single batteries (1); a communication groove (141) is formed in the partition plate (14) and is used for communicating the first chamber with the second chamber; the fifth through holes (13) are positioned at the bottom of the first chamber, and the ports of the first branch pipes (42) of the gas communicating pipe (4) penetrate through the fifth through holes (13) and are positioned in the first chamber; the second chamber is used for placing the battery cell.

8. The battery pack according to claim 7, wherein: the communication groove (141) is positioned at the bottom of the partition plate (14).

9. The battery pack of claim 8, wherein: the top of the liquid storage bin (2) is provided with a liquid injection port (21), and the top of the liquid storage bin (2) is also provided with a pressure release valve (22).

10. The battery pack according to claim 7, wherein: the main pipeline (41) of the gas communicating pipe (4) comprises a plurality of three-way pipes (411) and a plurality of ventilation sub-pipelines (412), and every two ventilation sub-pipelines (412) are connected through one three-way pipe (411) to form the main pipeline (41); the outer walls of the first branch pipe (42) and the second branch pipe (43) are provided with positioning bosses (413), and the outer wall of the first branch pipe (42) extending out of the lower cover plate (11) of the single battery (1) is provided with external threads; the outer wall of the second branch pipe (43) extending out of the lower cover plate of the liquid storage bin (2) is provided with external threads; the thread sections of the first branch pipe (42) and the second branch pipe (43) are connected with the vertical ports of the tee pipe (411).