CN220324641U - High-capacity battery - Google Patents

Abstract

The utility model belongs to the field of batteries, and particularly relates to a high-capacity battery. The problem that the existing high-capacity battery takes the shared pipe as the explosion venting pipe to easily cause explosion is solved. Comprises a plurality of unit batteries connected in parallel, a first hollow member and a second hollow member; each single battery comprises an electrolyte area and a gas area; the first hollow member extends along the arrangement direction of the plurality of single batteries, is fixed at the bottom of each single battery shell, is communicated with the inner cavity of each single battery, and the electrolyte area of each single battery is communicated with the first hollow member; the second hollow member extends along the arrangement direction of the plurality of single batteries, is fixed at the top of each single battery shell, and covers the explosion venting part at the top of each single battery; when the inner cavity pressure of any single battery is overlarge, the inner cavity gas or the thermal runaway flue gas breaks through the explosion venting part on each single battery, enters the second hollow component and is discharged, so that the safety is relatively high.

Description

High-capacity battery

Technical Field

The utility model belongs to the field of batteries, and particularly relates to a high-capacity battery.

Background

At present, single batteries in parallel or in series, such as cylindrical batteries, square-shell batteries and soft-package batteries, are mostly used in the market to form large-capacity batteries.

The existing high-capacity battery (also called as a battery module or a battery pack) comprises a plurality of unit batteries connected in parallel and a shared pipeline assembly positioned at the bottom of each unit battery; the shared pipeline assembly is used for completely penetrating the inner cavities of the plurality of single batteries so that all the single batteries in the large-capacity battery are in an electrolyte system; the uniformity of the electrolyte of each single battery in the high-capacity battery can be enhanced through the shared pipeline assembly, the cycle life is prolonged, and the service life of the high-capacity battery can be prolonged through the electrolyte supplementing of the shared pipeline assembly.

In addition, the shared pipeline assembly can also be used as a explosion venting pipe, and when the shared pipeline assembly is used as the explosion venting pipe, an explosion venting film needs to be arranged at any end of the shared pipeline assembly. When thermal runaway happens to any single battery, the electrolyte is extruded by the thermal runaway flue gas, so that the pressure at the end part of the sharing pipeline component is larger than the pressure which can be borne by the explosion venting membrane, the explosion venting membrane is burst, and the thermal runaway flue gas is discharged from the sharing pipeline component.

For such a large-capacity battery, when a certain single battery is in thermal runaway, the internal thermal runaway flue gas needs to be discharged after extruding part of electrolyte in the single battery and the sharing pipe assembly, and because the bottoms of the single batteries are communicated with the sharing pipe assembly, the electrolyte in the other single batteries flows into the sharing pipe assembly due to the action of gravity while the electrolyte in the sharing pipe assembly is discharged, so the thermal runaway flue gas may also need to be discharged after extruding the electrolyte in the other single batteries.

In conclusion, when the thermal runaway of the high-capacity battery occurs, the pressure holding time is longer, and the explosion venting effect is not ideal.

Disclosure of Invention

The utility model aims to provide a high-capacity battery, which solves the problem that the existing high-capacity battery takes a shared pipe assembly as a explosion venting pipe and has an unsatisfactory explosion venting effect due to long pressure holding time.

The technical scheme of the utility model is to provide a high-capacity battery, which is characterized in that: comprises a second hollow component and a plurality of unit batteries connected in parallel; each single battery cavity comprises an electrolyte area and a gas area;

the second hollow member comprises a second hollow box body with an open top and a second cover plate for covering the open top; the second hollow member extends along the arrangement direction of the plurality of single batteries, is fixedly connected with the top of each single battery through the bottom of the second hollow box body, and covers the explosion venting part at the top of each single battery; when any single battery explosion venting part is broken by inner cavity smoke, the gas area of the single battery is communicated with the second hollow component.

Further, in order to reduce the difference between the single batteries and improve the cycle performance of the large-capacity battery, the large-capacity battery further comprises a first hollow member, wherein the first hollow member extends along the arrangement direction of the single batteries, is fixedly connected with the bottom of the single battery shell, and is communicated with the electrolyte area of the single battery.

Further, a first through hole is formed in the bottom of the shell of each single battery; the first hollow member is provided with a plurality of second through holes which are in one-to-one correspondence with the first through holes and are communicated with the first through holes.

Further, in order to realize mass production, the first hollow member includes a first hollow case having an open bottom and a first cover plate for covering the open end; the second through hole is formed in the top of the first hollow box body; orthographic projection of the second through holes at the bottom of each single battery shell completely covers the corresponding first through holes;

the first hollow member is fixed to the bottom of each cell case by:

positioning the first hollow box body at the bottom of each single battery shell so that each first through hole corresponds to each second through hole one by one;

extending the welding head from the open end of the bottom of the first hollow box body to the edge part of the second through holes, and sealing and welding the edges of the second through holes with the bottoms of the shells of the corresponding single batteries;

and sealing and welding the first cover plate at the bottom open end of the first hollow box body.

The first through hole and the second through hole can also be communicated through a third hollow member; the first hollow member includes a first hollow case having an open bottom and a first cover plate for covering the open end; the second through hole is formed in the top of the first hollow box body;

The caliber of the second through hole is larger than the caliber of the connecting end of the third hollow member and the second through hole, so that the third hollow member can be inserted into the second through hole;

the first hollow member is fixed to the bottom of each cell case by:

welding each third hollow member at each first through hole;

positioning the first hollow box body at the bottom of each single battery shell so that each third hollow member corresponds to each second through hole one by one, and ensuring that each third hollow member is inserted into the second through hole;

extending the welding head from the bottom open end of the first hollow box body to the edge part of the second through holes, and welding the edges of the second through holes with the outer wall of the corresponding third hollow member to realize sealing;

and sealing and welding the first cover plate at the bottom open end of the first hollow box body.

Further, the second hollow member may have the same structure as the first hollow member, such as the second hollow member also including a second hollow case having an open top and a second cover plate for covering the opening; the bottom of the second hollow box body is provided with third through holes which are in one-to-one correspondence with the explosion venting parts; orthographic projection of the third through hole on the top of each single battery shell completely covers the corresponding explosion venting part;

The second hollow member is fixed on top of each cell housing by:

positioning the second hollow box body at the top of each single battery shell so that each explosion venting part corresponds to each third through hole one by one;

extending the welding head from the open end of the top of the second hollow box body to the edge of the third through hole, and sealing and welding the edges of the third through holes with the tops of the shells of the corresponding single batteries; after the explosion venting parts at the tops of the single batteries are broken through by the inner cavity smoke, the explosion venting parts of the single batteries are communicated with the corresponding third through holes;

and sealing and welding the second cover plate at the top open end of the second hollow box body.

Further, the second hollow member includes a second hollow case having an open top and a second cover plate for covering the open top; the bottom of the second hollow box body is provided with third through holes which are in one-to-one correspondence with the explosion venting parts;

further comprising a fourth hollow member;

the fourth hollow component is used for connecting the explosion venting part and the third through hole; the caliber of the third through hole is larger than the caliber of the connecting end of the fourth hollow member and the third through hole, so that the fourth hollow member can be inserted into the third through hole;

the second hollow member is fixed on top of each cell housing by:

Welding each fourth hollow member at the explosion venting part of each single battery respectively;

positioning the second hollow box body at the top of each single battery shell so that each fourth hollow member corresponds to each third through hole one by one, and ensuring that each fourth hollow member is inserted into each third through hole;

extending the welding head from the top open end of the second hollow box body to the edge part of the third through hole, and welding the edges of each third through hole with the outer wall of the corresponding fourth hollow member to realize sealing;

and sealing and welding the second cover plate at the top open end of the second hollow box body.

Further, the bottom of the second hollow box body is provided with third through holes which are in one-to-one correspondence with the explosion venting parts;

further comprising a fourth hollow member;

one end of the fourth hollow member is connected with the peripheral area of the explosion venting part, the other end of the fourth hollow member is inserted into the third through hole, and one section of the fourth hollow member inserted into the third through hole is a threaded section;

and the second hollow box body is fixed at the top of each single battery through the matching of the nut and the threaded section of the fourth hollow member.

The beneficial effects of the utility model are as follows:

1. according to the utility model, the second hollow member is arranged at the top of the high-capacity battery and is used as the explosion venting pipe, when the inner cavity pressure of any single battery is overlarge, the explosion venting part on each single battery is broken through by inner cavity gas or thermal runaway smoke to enter the second hollow member, and the explosion venting part is discharged from the second hollow member; because each single battery is provided with the explosion venting part, and the explosion venting parts are positioned in the gas areas of the single batteries, the thermal runaway flue gas can directly burst the explosion venting parts without overcoming electrolyte pressure, and enters the explosion venting pipe, the pressure holding time is shorter, and the safety is higher. And through setting up the second cavity component as split structure, be convenient for fix it at each battery cell top from the open end of second cavity box, reduce the processing degree of difficulty and processing cost, the yield is higher.

2. According to the utility model, the first hollow member is 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 the single batteries are communicated, so that the electrolytes of all the single batteries are in the same system, the difference among the electrolytes of all the single batteries is reduced, the consistency among the single batteries is improved to a certain extent, and the cycle life of the high-capacity battery is prolonged to a certain extent.

3. The utility model designs the first hollow component as a split piece, wherein one part is a first hollow box body with one end open, and the other part is a first cover plate covering the opening of the first hollow box body; when concrete welding, the welding head stretches into from open end, will set up the border and the welding of each battery cell bottom of the second through-hole at first hollow box top, realizes the link up of first through-hole and second through-hole, accomplishes the connection of first hollow box and each battery cell simultaneously, welds first apron at open end at last. The utility model only needs to ensure that the orthographic projection of the second through holes at the bottom of each single battery covers the corresponding first through holes, each first through hole is positioned on the same plane as much as possible, each second through hole is positioned on the same plane as much as possible, concentricity of the first through holes and the second through holes and consistency of each first through hole and the second through hole are not needed to be considered, requirements on processing precision and assembly precision are low, and influences of the processing precision and the assembly precision on the finished product rate are weakened; and during welding, the welding head stretches into from the open end, does not have any shielding, can once only accomplish the welding of second through hole border and each battery cell bottom, and the process is simple, and sealed effectual, can realize batch production.

4. The utility model can also utilize the third hollow component to communicate the first through hole and the second through hole, when in specific welding, the welding head stretches into from the open end, the edge of the second through hole is welded with the third hollow component, the through of the first through hole and the second through hole is realized, the connection of the first hollow component and each single battery is finished, and finally the first cover plate is welded at the open end. According to the utility model, only the caliber of one end of the third hollow member matched with the second through hole is smaller than that of the second through hole, so that the third hollow member can be inserted into the second through hole, the tightness between the third hollow member and the second through hole is not required, and the third hollow member and the second through hole are sealed by welding, so that the concentricity requirement on the third hollow member and the second through hole is not high, the requirements on the machining and assembling precision are lower, and the influence of the machining and assembling precision on the product yield is weakened; and during welding, the welding head stretches into from the open end, is not shielded, can once only accomplish the welding of second through hole border and third cavity component lateral wall or terminal surface, and the process is simple, and sealed effectual, can realize batch production.

And when the dimension of each single battery in the height direction is different due to processing errors, if the upper cover plates of the single batteries are positioned on the same plane, and the lower cover plates of the single batteries cannot be kept on the same plane, the first through holes and the second through holes are communicated through the third hollow member, and the height difference between the lower cover plates can be compensated in the height direction by the third hollow member.

5. The utility model designs the second hollow component as a split piece, wherein one part is a second hollow box body with one open end, and the other part is a second cover plate for covering the open end of the second hollow box body; during specific welding, the welding head stretches in from the open end, the edge of the third through hole formed in the bottom of the second hollow box body is welded with the upper cover plate of each single battery, and finally the second cover plate is welded at the open end. According to the utility model, only the orthographic projection of the third through holes on the tops of all the single batteries is required to cover the corresponding explosion venting parts, all the explosion venting parts are positioned on the same plane as much as possible, all the third through holes are positioned on the same plane as much as possible, concentricity of the explosion venting parts and the third through holes and consistency of all the third through holes are not required to be considered, requirements on processing precision and assembly precision are low, and influences of the processing precision and the assembly precision on the product yield are weakened; and during welding, the welding head stretches into from the open end, no shielding is caused, the welding between the edge of the third through hole and the top of each single battery can be completed at one time, the process is simple, the sealing effect is good, and batch production can be realized.

6. The utility model can also utilize the fourth hollow component to connect the explosion venting part and the third through hole, when in specific welding, the welding head stretches into from the open end, the edge of the third through hole is welded with the fourth hollow component, and finally the second cover plate is welded at the open end. According to the utility model, the caliber of one end of the fourth hollow member matched with the third through hole is smaller than that of the third through hole, so that the fourth hollow member can be inserted into the third through hole, the tightness between the fourth hollow member and the third through hole is not required, and the fourth hollow member and the third through hole are sealed by welding, so that the requirement on concentricity of the fourth hollow member and the third through hole is not high, the requirements on processing and assembling precision are lower, and the influence of the processing and assembling precision on the product yield is weakened; and during welding, the welding head stretches into from the open end, is not shielded, can finish the welding of the edge of the third through hole and the side wall or the end face of the fourth hollow member at one time, has simple process and good sealing effect, and can realize batch production.

And when the dimension of each single battery in the height direction is different due to processing errors, if the lower cover plates of the single batteries are positioned on the same plane, and the upper cover plates of the single batteries cannot be kept on the same plane, the explosion venting part and the third through hole are connected through the fourth hollow member, and the height difference between the upper cover plates can be compensated in the height direction by the fourth hollow member.

Drawings

Fig. 1 is a schematic view of the structure of a large-capacity battery of embodiment 1;

fig. 2 is a schematic structural view of a large-capacity battery of embodiment 2;

fig. 3 is a schematic structural diagram of a single cell in embodiment 2;

fig. 4 is a schematic structural view of the first hollow member in embodiment 2, wherein a and b are schematic views from different angles;

fig. 5 is an assembly schematic diagram of each unit cell and the first hollow member in embodiment 2;

fig. 6 is another assembly schematic diagram of each unit cell and the first hollow member in embodiment 2;

Fig. 7 is a schematic view of a part of the structure of a second hollow member in embodiment 2;

fig. 8 is another schematic view of the single cell in embodiment 2;

fig. 9 is a diagram showing an assembly process of each unit cell and the second hollow member in embodiment 2;

fig. 10 is a diagram showing a second assembly process of each unit cell and the second hollow member in embodiment 2;

fig. 11 is an assembly schematic diagram of each unit cell and the second hollow member in embodiment 2;

fig. 12 is another assembly schematic diagram of each unit cell and the second hollow member in embodiment 2;

fig. 13 is a schematic view of each unit cell in example 3;

the reference numerals in the drawings are:

1. a single battery; 2. a first hollow member; 3. a second hollow member; 4. explosion venting parts; 5. a first through hole; 6. a second through hole; 7. a first hollow case; 8. a first cover plate; 9. the top of the first hollow box body; 10. an open end; 11. a second through hole edge; 12. a third hollow member; 13. a second hollow box; 14. a second cover plate; 15. a third through hole; 16. a fourth hollow member; 17. an upper cover plate; 18. a lower cover plate; 19. a positioning groove; 20. a third through hole edge; 21. a liquid injection port; 22. a housing; 23. a fifth through hole; 24. a finished battery; 25. and (3) a nut.

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. All other embodiments, which can be made by one of ordinary skill in the art based on the embodiments of the present utility model without making any inventive effort, shall fall within the scope of the present utility model.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present utility model, but the present utility model may be practiced in other ways other than those described herein, and persons skilled in the art will readily appreciate that the present utility model is not limited to the specific embodiments disclosed below.

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 orientation or positional relationship indicated by "top, bottom, inner and outer", etc. in terms are based on the orientation or positional relationship shown in the drawings, 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 orientation, be constructed and operated in a specific orientation, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first through sixth" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

Example 1

As shown in fig. 1, the present embodiment provides a large-capacity battery including a second hollow member 3 and a plurality of unit cells 1 connected in parallel; each single battery 1 inner cavity comprises a gas area and an electrolyte area; the second hollow member 3 extends along the arrangement direction of the plurality of single batteries 1, is fixed on the top of each single battery 1, and covers the explosion venting part on the top of each single battery 1; when any of the unit cells 1 is broken, the gas region of the unit cell 1 communicates with the second hollow member 3. When the pressure in the inner cavity of any single battery 1 is overlarge, the second hollow member 3 is used as a explosion venting pipe, and the explosion venting part on each single battery 1 is broken through by inner cavity gas or thermal runaway smoke, so that the explosion venting part enters the second hollow member 3 and is discharged from the second hollow member 3.

The second hollow member 3 of the present utility model is a hollow box body, and may be a hollow box body having a rectangular cross section or a hollow box body having a semicircular cross section. The specific second hollow component 3 adopts split structure, including the open second hollow box in top and be used for covering the second apron of open end, be convenient for fix it at each battery cell top from the open end of second hollow box, if can adopt welded mode fixed, also can adopt threaded connection to cooperate sealed mode fixed of sealing washer.

The explosion venting part of the utility model comprises an explosion venting opening or an explosion proof opening with an explosion venting membrane, which is arranged at the top of the single battery, and can also be an explosion venting valve and the like.

Example 2

As shown in fig. 2, the large-capacity battery of the present embodiment adds the first hollow member 2 on the basis of embodiment 1. The specific large-capacity battery comprises 9 parallel single batteries 1, and the number of the single batteries can be adjusted according to actual requirements in other embodiments. Referring to fig. 3, the single battery 1 is a single square battery, and the single square battery includes an upper cover 17, a lower cover 18, a cylinder and a battery cell assembly; the cell assembly may also be referred to herein as an electrode assembly, which is assembled by sequentially arranging a positive electrode, a separator, and a negative electrode, using a lamination or winding process. The upper cover plate 17, the cylinder body and the lower cover plate 18 form a battery shell, and the battery cell assembly is arranged in the battery shell. Referring to fig. 4, in order to facilitate subsequent processing and assembly, the cross section of the first hollow member 2 of this embodiment is rectangular, extends along the arrangement direction of the plurality of unit cells 1, and is fixed to the bottom of each unit cell 1, where the bottom can be understood as the lower cover 18 of each unit cell 1. The electrolyte areas of the respective unit cells 1 are communicated through the first hollow member 2. The method is realized by the following scheme:

1) This can be achieved by perforating the lower cover 18 of each cell 1 and the first hollow member 2, specifically by providing the lower cover 18 of each cell 1 with a first through hole 5 (see fig. 3); second through holes 6 (see a diagram in fig. 4) corresponding to the first through holes 5 of each single battery 1 are correspondingly formed on the top of the first hollow box body 7. After the first through holes 5 and the second through holes 6 are communicated, the electrolyte in each single battery 1 can enter the first hollow member 2 through the first through holes 5 and the second through holes 6.

2) The method can also be realized by a mode of perforating any side wall of each single battery cylinder and a first hollow member, specifically, a first through hole is arranged on any side wall of each single battery cylinder; second through holes corresponding to the first through holes of the single batteries one by one are correspondingly formed in the top of the first hollow box body. After the first through hole and the second through hole are communicated through an external pipeline, electrolyte in each single battery can enter the first hollow component through the first through hole and the second through hole. But this solution is relatively complex, so this embodiment prefers solution 1).

When the scheme 1) is adopted, the penetration of the first through hole 5 and the second through hole 6 may adopt the following scheme:

The first hollow component 2 is formed by directly performing sealing grafting by interference fit of a plurality of sections of first sub-pipelines; at this time, the first sub-pipelines of the multiple sections are arranged on the lower cover plate 18 of the single battery 1 one by one, extend along the arrangement direction of the single battery 1, are integrally extruded with the lower cover plate 18, and are communicated with the first through hole 5 of the lower cover plate 18.

During assembly, first sub-pipelines are integrally formed on the lower cover plate 18, and in order to facilitate the plugging between the two first sub-pipelines, the length of the first sub-pipelines needs to be longer than that of the lower cover plate 18, that is, at least one end of the first sub-pipelines serving as a connecting end needs to extend out of the lower cover plate 18 at the moment, so that effective connection between the two first sub-pipelines can be ensured. And then the lower cover plate 18 is welded with the cylinder, then the battery cell assembly is assembled, and the upper cover plate 17 is welded, so that the single battery 1 is assembled. According to this method, all the unit cells 1 are assembled. And then, two ends of the first sub-pipeline are used as connecting ends with the other sub-pipeline, when the two single batteries 1 are connected, one end of the first sub-pipeline on one single battery 1 is extruded into the first sub-pipeline of the other single battery 1, and the two ends are in interference fit, so that the tightness after extrusion is ensured. And then electrolyte is injected into the inner cavity through the liquid injection port. The liquid injection port may be a liquid injection port on each unit cell 1, or may be a liquid injection port 21 formed on the first hollow member 2, so as to facilitate liquid injection. In addition, before electrolyte is injected into the inner cavity, the environment of the inner cavity needs to be ensured to be the environment with dew point standard of-25 to 40 ℃, humidity of less than or equal to 1 percent, temperature of 23+/-2 ℃ and cleanliness of 10 ten thousand grades. The inner cavity can reach the environmental standard by vacuumizing before liquid injection.

According to the scheme, through the first hollow member 2 in the plug-in type mode, electrolyte cavities of all the single batteries 1 are communicated, electrolyte of all the single batteries 1 is located in the same system, difference among the electrolyte of all the single batteries 1 is reduced, consistency among the single batteries 1 is improved to a certain extent, and accordingly cycle life of a large-capacity battery is prolonged to a certain extent.

This scheme requires each first sub-pipeline coaxial in the grafting process, just can realize effective connection, however, makes the axiality of each first sub-pipeline difficult to guarantee because of following reason:

1) The first sub-pipelines and the lower cover plate 18 are integrated, if the positions of the first sub-pipelines on the lower cover plate 18 are slightly deviated or the sizes of the first sub-pipelines are slightly deviated, the coaxiality of the first sub-pipelines is deviated during plugging;

2) When the integrated piece is welded with the cylinder, the situation that the positions of the first sub-pipelines relative to the cylinder are inconsistent possibly occurs due to the difference of welding processes, so that the coaxiality of each first sub-pipeline is deviated when the first sub-pipelines are spliced;

3) According to the scheme, when the first sub-pipelines are spliced, special tools are needed, and due to improper use of the tools or operation problems of constructors, the coaxiality of the first sub-pipelines is deviated;

In addition, when the first sub-pipelines are connected in an inserting mode, deviation among the first sub-pipelines can be increased along with the increase of the inserting quantity, so that the coaxiality among the first sub-pipelines is difficult to ensure as the inserting quantity is increased; resulting in a decrease in yield with an increase in the number of pins during assembly.

In summary, in this solution, the sub-pipes of two adjacent unit batteries 1 are difficult to be coaxial, so that when the sub-pipes are plugged, the first sub-pipe may be displaced relative to the lower cover 18, or the lower cover 18 may be displaced relative to the cylinder, thereby causing damage to the battery.

Simultaneously, this scheme adopts plug-in type's first cavity component, because the extrusion intensity of each grafting position is different, when thermal runaway takes place, because of inner chamber pressure increase, can make the position that extrusion intensity is weaker appear the gap, and when pressure further increases, the risk of disconnection can appear in this position, and then leads to the inner chamber electrolyte to reveal, initiates more serious incident.

The second scheme is that the first hollow member 2 comprises a hollow box body with a rectangular cross section, wherein the hollow box body is of a split structure and is composed of a first hollow box body 7 with an open end 10 at the top and a first cover plate 8 for covering the open end 10; a second through hole 6 is formed in the top of the first hollow box body 7, as shown in fig. 4;

During assembly, firstly, the cylinder body and the lower cover plate 18 are welded, the battery cell assembly is assembled, then the upper cover plate 17 is welded, and the assembly of the spare single battery is completed, wherein the spare single battery can be understood as a single battery 1 without electrolyte injection; secondly, as shown in fig. 5, the top of the first hollow box 7 and the bottom of each single battery 1 are positioned, so that each first through hole 5 corresponds to each second through hole 6 one by one, and the projection of each second through hole 6 on the bottom of each single battery 1 is ensured to completely cover the corresponding first through hole 5, and the positioning can be realized through a positioning groove 19 shown in fig. 4; extending the welding head from the bottom open end 10 of the first hollow box 7 to the position of the second through hole edges 11, and sealing and welding each second through hole edge 11 with the lower cover plate 18 of the corresponding single battery 1; so that the first through holes 5 of the individual battery cells 1 are communicated with the corresponding second through holes 6; the first cover plate 8 is sealed and welded to the bottom open end 10 of the first hollow box 7. Finally, electrolyte is injected into the inner cavity through the liquid injection port 21. The liquid filling port 21 is formed in the first hollow member 2, so that liquid can be filled conveniently, and liquid can be replaced through the liquid filling port 21 in the later stage. Note that, the liquid inlet 21 needs to be sealed by a stopper when liquid is not injected. In addition, before electrolyte is injected into the inner cavity, the environment of the inner cavity needs to be ensured to be the environment with dew point standard of-25 to 40 ℃, humidity of less than or equal to 1 percent, temperature of 23+/-2 ℃ and cleanliness of 10 ten thousand grades. The inner cavity can reach the environmental standard by vacuumizing before liquid injection. It should be noted that the welding head as used herein refers to a member of the welding apparatus extending into the portion to be welded, if arc welding or argon arc welding is used, the welding head as used herein refers to an end portion of the electrode, and if laser welding is used, the welding head as used herein refers to a laser beam.

In the assembly, in the first step, electrolyte can be directly injected into the spare single battery, and the first through hole 5 is sealed by the sealing component; and (5) separating the capacity, and selecting the single batteries 1 meeting the requirements. After the first hollow member 2 and each unit cell 1 are welded, the sealing assembly is opened under the action of external force or electrolyte, so that the first through hole 5 is communicated with the corresponding second through hole 6.

The first hollow member 2 may also be welded to each lower cover plate 18 first, so that the first through hole 5 on each lower cover plate 18 and the corresponding second through hole 6 are penetrated; then each cylinder is welded on the corresponding lower cover plate 18, and then is assembled into a battery cell assembly, and the upper cover plate 17 is welded; finally, electrolyte is injected into the cavity of the large-capacity battery through the first hollow member 2 to be formed. The lower cover plate 18 and the cylinder body can also be integrally formed, and after the first hollow member 2 is welded on each lower cover plate 18, the battery cell assembly can be directly assembled, and the upper cover plate 17 is welded.

According to the scheme, the first hollow member 2 does not need to be inserted, the coaxial inserting problem does not need to be considered in the arrangement direction of the single battery 1, the problem that the first hollow member is damaged due to overlarge inner cavity pressure does not need to be worried, only the first through holes 5 are located on the same plane as much as possible, the second through holes 6 are located on the same plane as much as possible, the concentricity of the first through holes 5 and the second through holes 6 and the consistency of the first through holes 5 and the second through holes 6 do not need to be considered, the requirements on processing precision and assembly precision are low, and the influence of the processing precision and the assembly precision on the product yield is weakened; meanwhile, a special tool is not needed, and the assembly process is simpler; and during welding, the welding head stretches into from the open end 10, no shielding is caused, the welding between the second through hole edge 11 and the bottom of each single battery 1 can be completed at one time, the process is simple, the sealing effect is good, and batch production can be realized.

The third scheme is that the first hollow member 2 comprises a hollow box body with a rectangular cross section, wherein the hollow box body is of a split structure and is composed of a first hollow box body 7 with an open end 10 at the top and a first cover plate 8 for covering the open end 10; the bottom of the first hollow box body 7 is provided with a second through hole 6; the first through hole 5 and the second through hole 6 communicate through the third hollow member 12;

during assembly, firstly, the cylinder body and the lower cover plate 18 are welded, the battery cell assembly is assembled, then the upper cover plate 17 is welded, and the assembly of the spare battery cell is completed, wherein the spare battery cell can be understood as a battery cell 1 without electrolyte injection; next, each third hollow member 12 is welded at the first through hole 5 of each unit cell 1, respectively; positioning the first hollow case 7 with the bottom of each unit cell 1 so that each third hollow member 12 corresponds one-to-one to each second through hole 6 and ensuring that each third hollow member 12 is inserted into the second through hole 6, as shown in fig. 6; extending the welding head from the bottom open end 10 of the first hollow box 7 to the position of the second through hole edges 11, and welding each second through hole edge 11 with the outer wall of the corresponding third hollow member 12 to realize sealing; when the end face of the third hollow member 12 is flush with the inner bottom face of the first hollow box 7, the end face of the third hollow member 12 can be directly welded with the second through hole edge 11 to realize sealing. The first cover plate 8 is welded at the bottom open end 10 of the first hollow box body 7 in a sealing manner (the first cover plate 8 and the bottom open end of the first hollow box body 7 can be connected in a sealing manner by bonding and screw connection manners, and the preferred welding manner in the embodiment is connected to ensure the sealing reliability of the connection portion). Finally, electrolyte is injected into the inner cavity through the liquid injection port 21. The liquid filling port is formed in the first hollow member 2 so as to facilitate liquid filling, and liquid exchange can be realized through the liquid filling port in the later stage. In other embodiments, the liquid filling port may be a liquid filling port of each unit cell. In addition, before electrolyte is injected into the inner cavity, the environment of the inner cavity needs to be ensured to be the environment with dew point standard of-25 to 40 ℃, humidity of less than or equal to 1 percent, temperature of 23+/-2 ℃ and cleanliness of 10 ten thousand grades. The inner cavity can reach the environmental standard by vacuumizing before liquid injection. In addition, the liquid injection port formed in each unit cell or the first hollow member needs to be sealed by a plug when no liquid is injected.

In the first step, electrolyte can be directly injected into the spare single battery, and the first through hole 5 is sealed by the sealing component; and separating a plurality of single batteries 1 meeting the requirements according to the capacity. After the first hollow member 2 and each unit cell 1 are welded, the sealing assembly is opened under the action of external force or electrolyte, so that the first through hole 5 is communicated with the corresponding second through hole 6.

The first hollow member may also be welded to each lower cover plate 18 first, so that the first through hole 5 on each lower cover plate 18 and the second through hole 6 corresponding thereto are penetrated; then each cylinder is welded on the corresponding lower cover plate 18, and then is assembled into a battery cell assembly, and the upper cover plate 17 is welded; finally, electrolyte is injected into the cavity of the large-capacity battery through the first hollow member 2 to be formed.

According to the scheme, the first hollow member 2 does not need to be inserted, the coaxial inserting problem does not need to be considered in the arrangement direction of the single battery 1, the problem that the first hollow member is damaged due to overlarge inner cavity pressure does not need to be worried, meanwhile, the flatness requirements on each first through hole 5 and each second through hole 6 are not high, only the caliber of one end of the third hollow member 12 matched with the second through hole 6 is smaller than that of the second through hole 6, the third hollow member 12 can be inserted into the second through hole 6, the tightness between the third hollow member 12 and the second through hole 6 after the third hollow member 12 is not required, and the third hollow member 12 and the second through hole 6 are sealed through welding, so that the concentricity requirements on the third hollow member 12 and the second through hole 6 are not high, the processing and assembling precision requirements are low, and the influence of the processing and assembling precision on the product yield is weakened; and during welding, the welding head stretches into from the open end 10, is not shielded, can finish the welding of the second through hole edge 11 and the side wall or the end face of the third hollow member 12 at one time, has simple process and good sealing effect, and can realize batch production.

By comparing and analyzing the schemes, the structure and the assembly method of the scheme II and the scheme III are selected in the embodiment.

Referring to fig. 7, in order to facilitate subsequent processing and assembly, in this embodiment, the second hollow member 3 and the first hollow member 2 are identical in structure and are hollow boxes with rectangular cross sections, the second hollow member 3 extends along the arrangement direction of the plurality of unit cells 1, and is fixed on top of each unit cell 1, where the top can be understood as an upper cover plate 17 of each unit cell 1, and covers the explosion venting portion 4 on the upper cover plate 17, and the position of the explosion venting portion 4 can be shown in fig. 8. When the explosion venting part 4 of any single battery 1 is broken by inner cavity smoke, the gas area of the single battery 1 is communicated with the second hollow member 3. The second hollow member 3 is provided with third through holes 15 which are in one-to-one correspondence with the explosion venting parts 4; the peripheral area of the explosion venting portion 4 and the third through hole 15 can be connected by adopting the following scheme:

the first and second hollow members 3 comprise hollow boxes with rectangular cross sections, wherein the hollow boxes are of split structures and are composed of a second hollow box 13 with an open end 10 at the top and a second cover plate 14 for covering the open end 10 (see fig. 7); the third through hole 15 is formed in the bottom of the second hollow box 13;

During assembly, firstly, the assembly of the spare single battery is completed; the spare battery cell herein may be understood as a battery cell into which the electrolyte is not injected; secondly, the second hollow box 13 is positioned with the top of each spare single battery, so that each explosion venting part 4 corresponds to each third through hole 15 one by one, and the projection of each third through hole 15 on the top of each single battery 1 is ensured to completely cover the corresponding explosion venting part 4; extending the welding head from the top open end 10 of the second hollow box 13 to the position of the third through hole edge 20, and sealing and welding each third through hole edge 20 with the upper cover plate 17 of the corresponding standby single battery; so that the explosion venting part 4 of each spare single battery corresponds to the third through hole 15; the second cover plate 14 is sealingly welded to the top open end 10 of the second hollow housing 13 as shown in fig. 9 and 10.

In the scheme, the explosion venting parts 4 are only required to be positioned on the same plane as much as possible, the third through holes 15 are positioned on the same plane as much as possible, the first through holes 5 are positioned on the same plane as much as possible, and the second through holes 6 are positioned on the same plane as much as possible, so that concentricity of the explosion venting parts 4, the third through holes 15, the first through holes 5 and the second through holes 6 is not required to be considered; the consistency of the first through holes 5, the second through holes 6, the explosion venting part 4 and the third through holes 15 is not required to be considered, the requirements on the machining precision and the assembly precision are low, and the influence of the machining precision and the assembly precision on the product yield is weakened; meanwhile, a special tool is not needed, and the assembly process is simpler; and during welding, the welding head stretches into from the open end 10, no shielding is caused, the welding between the third through hole edge 20 and the top of each single battery 1 and between the second through hole edge 11 and the bottom of each single battery 1 can be completed at one time, the process is simple, the sealing effect is good, and batch production can be realized.

The second scheme is that the second hollow member 3 comprises a hollow box body with a rectangular cross section, wherein the hollow box body is of a split structure and consists of a second hollow box body 13 with an open end 10 at the top and a second cover plate 14 for covering the open end 10; a third through hole 15 is formed in the second hollow box body 13; the peripheral region of the explosion venting portion 4 and the third through hole 15 are connected by a fourth hollow member 16. The diameter of the third through-hole 15 needs to be slightly larger than the diameter of the connecting end of the fourth hollow member 16 and the third through-hole 15 so that the fourth hollow member 16 can be inserted into the third through-hole 15.

During assembly, firstly, the cylinder body and the upper cover plate 17 are welded, the battery cell assembly is assembled, and then the lower cover plate 18 is welded, so that the assembly of the single battery component is completed; secondly, positioning the second hollow box 13 and the top of each single battery 1 so that each explosion venting part 4 corresponds to each third through hole 15 one by one, so that each fourth hollow member 16 corresponds to each third through hole 15 one by one, and ensuring that each fourth hollow member 16 is inserted into the third through hole 15; extending the welding head from the top open end 10 of the second hollow box 13 to the position of the third through hole edges 20, and welding each third through hole edge 20 with the outer wall of the corresponding fourth hollow member 16 to realize sealing; when the end face of the fourth hollow member 16 is flush with the inner bottom face of the second hollow box 13, the third through hole edge 20 can be directly welded with the end face of the corresponding fourth hollow member 16 to realize sealing; so that the explosion venting portion 4 of each single battery 1 corresponds to the third through hole 15; the second cover plate 14 is sealingly welded to the top open end 10 of the second hollow housing 13 as shown in fig. 11.

The flatness requirements on the third through holes 15 are not high, only the caliber of one end of the fourth hollow member 16 matched with the third through holes 15 is required to be smaller than that of the third through holes 15, the fourth hollow member 16 can be inserted into the third through holes 15, the tightness between the fourth hollow member 16 and the third through holes 15 is not required, and the fourth hollow member 16 and the third through holes 15 are sealed through welding, so that the concentricity requirements on the fourth hollow member 16 and the third through holes 15 are not high, the requirements on the machining precision and the assembly precision are low, and the influence of the machining precision and the assembly precision on the product yield is weakened; meanwhile, a special tool is not needed, and the assembly process is simpler; and during welding, the welding head stretches into from the open end 10, is not shielded, can finish the welding of the second through hole edge 11 and the side wall or the end face of the fourth hollow member 16 at one time, has simple process and good sealing effect, and can realize batch production.

The third scheme is that the second hollow member 3 comprises a hollow box body with a rectangular cross section, wherein the hollow box body is of a split structure and is composed of a second hollow box body 13 with an open end 10 at the top and a second cover plate 14 for covering the open end 10; a third through hole 15 is formed in the second hollow box body 13; the peripheral region of the explosion venting portion 4 and the third through hole 15 are connected by a fourth hollow member 16. The caliber of the third through hole 15 needs to be slightly larger than the caliber of the connecting end of the fourth hollow member 16 and the third through hole 15, so that the fourth hollow member 16 can be inserted into the third through hole 15, unlike the second scheme, in the second scheme, a section of the fourth hollow member 16 inserted into the third through hole 15 is a threaded section, and it can be understood that the outer wall of the section is provided with threads.

During assembly, firstly, the cylinder body and the upper cover plate 17 are welded, the battery cell assembly is assembled, and then the lower cover plate 18 is welded, so that the assembly of the single battery component is completed; secondly, positioning the second hollow box 13 and the top of each single battery 1, wherein each explosion venting part 4 corresponds to each third through hole 15 one by one, so that each fourth hollow member 16 corresponds to each third through hole 15 one by one, and each fourth hollow member 16 is ensured to be inserted into the third through hole 15; the lock nut 25 is screwed on the threaded section of the fourth hollow member 16 so that the second hollow case 13 is fixed on top of each unit cell as shown in fig. 12.

The scheme has low requirements on the flatness of each third through hole 15, only the caliber of one end of the fourth hollow member 16 matched with the third through hole 15 is required to be smaller than that of the third through hole 15, the fourth hollow member 16 can be inserted into the third through hole 15, and the tightness between the fourth hollow member 16 and the third through hole 15 is not required after the fourth hollow member 16 is inserted, so that the requirements on the concentricity of the fourth hollow member 16 and the third through hole 15 are low, the requirements on the machining precision and the assembly precision are low, and the influence of the machining precision and the assembly precision on the product yield is weakened; meanwhile, a special tool is not needed, and the assembly process is simpler; and the nut 25 is matched with the fourth hollow member 16 to fix the second hollow box body at the top of each single battery, so that the operation is convenient, the process is simple, and the mass production can be realized.

It should be noted that:

when there is a difference in the dimensions of the individual battery cells 1 in the height direction due to a processing error, it is preferable that the first through hole 5 and the second through hole 6 are penetrated through the third hollow member 12, or the explosion venting portion 4 and the third through hole 15 are connected through the fourth hollow member 16, and of course, the explosion venting portion 4 and the third through hole 15 are connected through the fourth hollow member 16 while the first through hole 5 and the second through hole 6 are penetrated through the third hollow member 12; the height difference between the respective lower cover plates 18 or upper cover plates 17 can be compensated in the height direction by the third hollow member 12 and/or the fourth hollow member 16, and when a certain height difference exists in the respective lower cover plates 18 or upper cover plates 17 of the unit cells 1, the sealed communication of the first through holes 5 and the second through holes 6 can be ensured by the third hollow member 12, and the sealed communication of the explosion venting portion 4 and the third through holes 15 can be ensured by the fourth hollow member 16.

It should be noted that, after the first hollow member and the second hollow member are fixed at the corresponding positions (the second hollow member is located at the top of each single battery, and the first hollow member is located at the bottom of each single battery), the first through hole 5 and the corresponding second through hole 6 are penetrated, so as to complete electrolyte sharing; wherein the first hollow member and the second hollow member are secured in no order;

The first hollow member may be fixed at the corresponding position so that the first through hole 5 is communicated with the corresponding second through hole 6, and the second hollow member is fixed at the top of each single battery after the electrolyte sharing is completed.

Example 3

Unlike embodiment 2, as shown in fig. 13, the single battery 1 of this embodiment includes a housing 22 and a finished battery 24 (the finished battery 24 herein includes a finished commercial housing battery), the finished battery 24 is installed inside the housing 22, a fifth through hole 23 is provided at the bottom of the finished battery 24, and an explosion venting portion 4 is provided at the top. The first through hole 5 is provided at the bottom of the housing 22, and the first through hole 5 communicates with the fifth through hole 23; the top of the shell 22 is provided with a sixth through hole, and the explosion venting part 4 corresponds to the sixth through hole, and when the explosion venting part 4 is broken, the explosion venting part 4 and the sixth through hole are communicated.

The first hollow member 2 and the second hollow member 3 of this embodiment have the same structure as that of embodiment 2, but the assembly modes thereof are slightly different based on the difference in the structure of the single battery 1, mainly in that the assembly of the single battery 1 and the subsequent liquid injection process are different, and the assembly modes can adopt the following three modes:

1) During assembly, first, a fifth through hole 23 is formed in the bottom of the finished battery 24, and the fifth through hole 23 is sealed for later use by using a sealing assembly. Preferably, the fifth through hole 23 is opened and sealed by a corresponding sealing component under the environment that the dew point standard is between-25 and 40 ℃ and the humidity is less than or equal to 1 percent, the temperature is 23+/-2 ℃, and the cleanliness is 10 ten thousand grades. Second, the finished battery 24 after the treatment is assembled into the casing 22, so that the fifth through hole 23 with the sealing assembly corresponds to the first through hole 5, the sixth through hole corresponds to the explosion venting portion 4, and after the sealing assembly is opened, the fifth through hole 23 is communicated with the first through hole 5 to form the single battery 1. Third, the first hollow member 2 and the second hollow member 3 were fixed to the bottom and the top of each unit cell 1, respectively, according to the assembly method in embodiment 2. Finally, the sealing assembly is opened by using external force or electrolyte, so that the fifth through hole 23 is communicated with the first through hole 5, and in order to ensure the continuity of the electrolyte, the electrolyte can be injected into the inner cavities of all the single batteries through the first hollow member; in order to further improve the performance of the large-capacity battery, the electrolyte can be formed after being injected.

2) This solution differs from solution 1) in that the assembly of the battery cells 1 is maintained and the rest of the process is consistent. The unit cell 1 is assembled as follows: firstly, fixing a sealing assembly on a first through hole 5, and sealing the first through hole 5; secondly, a fifth through hole 23 is formed at the bottom of the finished battery 24, preferably in an environment with the dew point standard of-25 to 40 ℃ and humidity less than or equal to 1 percent, the temperature of 23+/-2 ℃ and the cleanliness of 10 ten thousand grades; finally, in the environment with the dew point standard of minus 25 to 40 ℃ and the humidity of less than or equal to 1 percent, the temperature of 23+/-2 ℃ and the cleanliness of 10 ten thousand grades, the finished battery 24 with the fifth through hole 23 is assembled inside the shell 22, so that the fifth through hole 23 corresponds to the first through hole 5, the explosion venting part 4 corresponds to the sixth through hole, and the fifth through hole 23 is communicated with the first through hole 5 after the sealing assembly is opened, so that the single battery 1 is formed.

3) First, fixing the first hollow member 2 at the bottom of each housing so that the first through holes 5 and the second through holes 6 are in one-to-one correspondence; the outer shell is understood to be an outer shell with an open top, and after the spare finished batteries are filled in the outer shells, the open top of the outer shell is sealed, so that the outer shells of the single batteries are welded; the standby finished battery is obtained through the following steps: separating the capacity, and screening a plurality of finished batteries meeting the requirements; a fifth through hole 23 is formed in the bottom of the screened finished battery; finally, the second hollow members 3 are fixed on the top of each housing, and the sealing assemblies sealed at the first through holes 5 and/or the fifth through holes are opened by external force or electrolyte so that the inner cavities of each single battery and the first hollow members are communicated.

Example 4

Unlike example 3, the battery cell 1 of this example is a commercially available finished square battery, and the structures of the first hollow member 2 and the second hollow member 3 of this example are the same as those of example 3, but the assembly method and the subsequent liquid injection process are slightly different based on the different structures of the battery cell 1:

in assembly, first, a first through hole 5 is formed in the bottom of the finished battery 24, preferably in an environment where the dew point is between-25 and 40 ℃, the humidity is less than or equal to 1%, the temperature is 23 ℃ +/-2 ℃, and the cleanliness is 10 ten thousand levels. Next, the first hollow member 2 and the second hollow member 3 were fixed to the bottom and the top of each unit cell 1, respectively, according to the assembly method in example 1. Finally, the sealing member sealed at the first through hole 5 is opened by an external force or the electrolyte itself so that the first through hole 5 and the second through hole 6 are penetrated.

Claims (8)

1. A high capacity battery characterized by: comprises a second hollow component (3) and a plurality of single batteries (1) which are connected in parallel; each single battery (1) inner cavity comprises an electrolyte area and a gas area;

the second hollow member (3) comprises a second hollow box (13) with an open top and a second cover plate (14) for covering the open top; the second hollow member (3) extends along the arrangement direction of the plurality of single batteries (1), is fixedly connected with the top of each single battery (1) through the bottom of the second hollow box body, and covers the explosion venting part (4) at the top of each single battery (1); when the explosion venting part (4) of any single battery (1) is broken by inner cavity smoke, the gas area of the single battery (1) is communicated with the second hollow member (3).

2. The high-capacity battery according to claim 1, wherein: the battery pack also comprises a first hollow member (2), wherein the first hollow member (2) extends along the arrangement direction of the plurality of single batteries (1), is fixedly connected with the bottom of the shell of each single battery (1), and is communicated with the electrolyte areas of each single battery (1).

3. The high-capacity battery according to claim 2, wherein: the bottoms of the single batteries (1) are provided with a first through hole (5); a plurality of second through holes (6) are formed in the first hollow member (2); the second through holes (6) are in one-to-one correspondence with the first through holes (5) and are mutually communicated.

4. A high-capacity battery as claimed in claim 3, wherein: the first hollow member (2) comprises a first hollow box (7) with an open bottom and a first cover plate (8) for covering the open end (10); the second through hole (6) is formed in the top of the first hollow box body (7); the edges (11) of the second through holes are welded with the bottoms of the shells of the corresponding single batteries (1) in a sealing mode, so that the second through holes (6) are in one-to-one correspondence with the first through holes (5) and are communicated with each other.

5. A high-capacity battery as claimed in claim 3, wherein: the first through hole (5) and the second through hole (6) are communicated through a third hollow member (12); the first hollow member (2) comprises a first hollow box (7) with an open bottom and a first cover plate (8) for covering the open end (10); the second through hole (6) is formed in the top of the first hollow box body (7); the caliber of the second through hole (6) is larger than that of the connecting end of the third hollow member (12) and the second through hole (6), and the edge (11) of the second through hole is welded with the outer wall of the corresponding third hollow member (12) to realize sealing.

6. The high-capacity battery as claimed in any one of claims 1 to 5, wherein: the bottom of the second hollow box body (13) is provided with third through holes (15) which are in one-to-one correspondence with the explosion venting parts (4); orthographic projection of the third through hole (15) on the top of the shell of each single battery (1) completely covers the corresponding explosion venting part (4);

the third through hole edge (20) is welded with the top of the shell of the corresponding single battery (1) in a sealing way.

7. The high-capacity battery as claimed in any one of claims 1 to 5, wherein: the bottom of the second hollow box body (13) is provided with third through holes (15) which are in one-to-one correspondence with the explosion venting parts (4);

further comprising a fourth hollow member (16); the fourth hollow member (16) is connected with the peripheral area of the explosion venting part (4) and the third through hole (15); the caliber of the third through hole (15) is larger than the caliber of the connecting end of the fourth hollow member (16) and the third through hole (15), so that the fourth hollow member (16) can be inserted into the third through hole (15);

the third through hole edge (20) is welded with the outer wall of the corresponding fourth hollow member (16) to realize sealing.

8. The high-capacity battery as claimed in any one of claims 1 to 5, wherein: the bottom of the second hollow box body (13) is provided with third through holes (15) which are in one-to-one correspondence with the explosion venting parts (4);

further comprising a fourth hollow member (16);

One end of the fourth hollow member (16) is connected with the peripheral area of the explosion venting part (4), the other end of the fourth hollow member is inserted into the third through hole (15), and one section of the fourth hollow member (16) inserted into the third through hole (15) is a threaded section;

the second hollow box body (13) is fixed on the top of each single battery through the matching of nuts and the threaded sections of the fourth hollow components (16).