CN115036624A

CN115036624A - Battery shell, battery and high-capacity battery

Info

Publication number: CN115036624A
Application number: CN202210599290.0A
Authority: CN
Inventors: 韩晓宇; 雷政军; 张三学; 翟腾飞
Original assignee: Shaanxi Olympus Power Energy Co Ltd
Current assignee: Shaanxi Olympus Power Energy Co Ltd
Priority date: 2022-05-30
Filing date: 2022-05-30
Publication date: 2022-09-09

Abstract

The invention provides a battery shell, a battery and a high-capacity battery, and mainly solves the problems that electrolytes of a plurality of batteries cannot mutually circulate and the performance of the electrolytes is not uniform. The battery shell comprises an upper cover component, a shell body and a liquid injection component; the shell body is provided with an opening communicated with the inner cavity of the shell body; the liquid injection assembly comprises a connecting pipe and a sealing film, and the connecting pipe is arranged on the shell body and is communicated with the inner cavity of the shell body through an opening; the sealing film is arranged in the opening of the shell body or in the connecting pipe so as to seal the battery shell; when electrolyte is injected from the outside of the battery shell to the inside through the liquid injection assembly, the sealing film is opened through external acting force or external pressure in the connecting pipe, so that the electrolyte enters the inside of the battery shell, the electrolyte in the plurality of battery shells is circulated mutually, the plurality of batteries are in an electrolyte system with uniform performance, and the service life of the batteries is prolonged.

Description

Battery shell, battery and high-capacity battery

Technical Field

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

Background

The lithium ion battery has the advantages of high packaging reliability, high system energy efficiency, simpler structure, relatively convenient capacity expansion and the like. With the further development of lithium ion batteries, a plurality of lithium ion batteries are connected in series to form a high-capacity lithium battery, so that the high-capacity lithium battery is applied to the fields of energy storage, power batteries and the like. However, when the lithium ion batteries are connected in series to form a large-capacity battery, the problem that the lithium ion batteries have stable electrical performance and high yield needs to be solved, wherein a key problem is how to provide the same working environment for each battery cell forming the large-capacity lithium ion battery.

Chinese patent CN212810407U proposes a square aluminum-casing battery, in which the sealing space formed by every two square aluminum casings and cover plates shares one adjacent surface and is connected together by a shared surface, thereby forming a connected square aluminum-casing battery. However, this structure simply connects each unit cell, and does not solve the problem that the electrolyte in the large-capacity battery and the electrolyte in the battery cell flow each other and the electrolyte performance is consistent.

Chinese patent CN202695666U provides a series high-capacity battery pack for energy storage, which comprises a housing containing electrolyte, at least 6 cells connected in series in sequence are installed in the housing, each cell is separated by a partition board containing micropores, and the electrolyte is shared between the cells. However, this structure cannot ensure the electrical property uniformity of each cell, and the errors of the capacitance, internal resistance, and charge-discharge characteristics of the plurality of cells are large.

Disclosure of Invention

In order to solve the problems that the electrolyte in a large-capacity battery and the electrolyte in a battery core cannot mutually circulate and the performance of the electrolyte is not uniform, the invention provides a battery shell, a battery and a large-capacity battery, wherein the electrolytes in a plurality of battery shells mutually circulate, so that a plurality of batteries are in a uniform electrolyte system, and the performance and the yield of the battery are improved.

In order to achieve the purpose, the technical scheme of the invention is as follows:

a battery case includes an upper cover assembly, a case body, and a liquid injection assembly: the upper cover assembly and the shell body enclose to form a battery shell; the shell body is provided with an opening communicated with the inner cavity of the shell body; the liquid injection assembly comprises a connecting pipe and a sealing film, and the connecting pipe is arranged on the shell body and is communicated with the inner cavity of the shell body through an opening; the sealing film is arranged in the opening of the shell body or in the connecting pipe so as to seal the battery shell; when electrolyte passes through annotate the subassembly and annotate from the casing body outside to inside, the seal membrane passes through the interior external force of connecting tube or external pressure and opens, so that electrolyte gets into in the casing body.

Further, an opening device is arranged in the connecting pipe, and the opening device can move in the connecting pipe under the action of external pressure or a sliding device, so that the opening device opens the sealing membrane.

Furthermore, one end of the opening device is provided with a jacking bulge or a jacking spike, and the other end of the opening device is provided with a round table.

Further, when the opening device moves in the connecting pipe under external pressure, the diameter of the circular truncated cone is smaller than or equal to the inner diameter of the connecting pipe, and pressure difference can be generated on two sides of the circular truncated cone.

Furthermore, a wedge-shaped surface is arranged on the side wall of the circular truncated cone of the opening device and used for being matched with the sliding device, so that the opening device can move quickly and accurately.

Furthermore, a plurality of through holes are formed in the side wall of one end, far away from the opening, of the connecting pipe in the circumferential direction and used for injecting electrolyte in the circumferential direction.

Further, the inside of the opening means is provided with a passage penetrating in the moving direction thereof.

Further, a positioning boss is arranged on the inner wall of the connecting pipe and used for limiting the opening device, so that the opening device can open the sealing membrane to avoid damaging an electrode assembly in the battery shell.

Further, the material of seal membrane is the same with the material of casing body, the seal membrane sets up with casing body is integrative, and the thickness of seal membrane is less than the wall thickness of casing body.

Further, the material of seal membrane is the same with the material of casing body, seal membrane and the integrative setting of casing body, be provided with the nick on the seal membrane for realize opening fast of seal membrane.

Further, be provided with the nick on the seal membrane for realize opening fast of seal membrane, the material of seal membrane is at least one of copper, aluminium, PP, PE, polytetrafluoroethylene.

Further, the opening is arranged on one side of the shell body far away from the upper cover assembly.

Meanwhile, the invention also provides a battery, which comprises an electrode assembly and the battery shell, wherein the electrode assembly is arranged in the battery shell and is soaked by the electrolyte.

In addition, the invention also provides a high-capacity battery which comprises a liquid storage pipe and a plurality of batteries, wherein the liquid storage pipe is communicated with the connecting pipes of the battery shells.

Further, a sliding device is arranged in the liquid storage pipe, the sliding device is a sliding rod, and the sliding rod is used for pushing the opening device to slide in the connecting pipe, so that the opening device opens the sealing film.

Further, a liquid injection device is arranged on the liquid storage pipe, and the liquid injection device is a liquid injection valve.

Further, the liquid storage pipe is also provided with an explosion venting device to vent out smoke generated when the large-capacity battery is out of control due to heat, and the explosion venting device is an explosion venting valve.

Compared with the prior art, the technical scheme of the invention has the following advantages:

1. according to the invention, the shell body is provided with the opening, the connecting pipe is arranged at the opening, the sealing film is arranged in the connecting pipe or the opening of the shell body, and when a single battery works, the sealing film seals the battery shell, so that electrolyte in the battery is isolated from external air. When a plurality of batteries are connected in parallel to form a large-capacity battery, the sealing film is opened through external acting force or external pressure in the connecting pipe, and electrolyte is injected, so that the electrolyte in the batteries is communicated, the batteries are in a uniform electrolyte system, and the consistency of the energy storage performance of each electrode assembly is greatly improved. Meanwhile, the mode is convenient for the liquid supplementing after the pre-charging and the capacity grading of the battery, the service life of the battery is prolonged, the operability is strong, the method is economical and practical, and the production efficiency and the yield of the battery are improved.

2. The sealing membrane is opened by external acting force or external pressure in the connecting pipe, the sealing membrane can be opened in a state of avoiding contact with air in the mode, the contact with water vapor in the air can be effectively prevented when the battery shell is opened, the operation method is simple and reliable, the water vapor isolation is good, other manufacturing processes of the battery are not increased, the operation is convenient, the performance and the yield of the battery are improved, the structure is simple, the installation is simple and convenient, and the universality is strong.

Additional advantages, objects, and features of the invention will be set forth in part in the description which follows and in part will become apparent to those having ordinary skill in the art upon examination of the following or may be learned from practice of the invention.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

Fig. 1 is a first schematic diagram of a battery case according to embodiment 1 of the present invention;

fig. 2 is a second schematic diagram of a battery case according to embodiment 1 of the present invention;

FIG. 3 is a schematic view showing a seal film of a battery case provided with scores according to example 1 of the present invention;

fig. 4 is a schematic view of a battery case in embodiment 2 of the invention;

fig. 5 is an exploded view schematically illustrating the structure of a large-capacity battery in examples 2 and 5 of the present invention;

FIG. 6 is a schematic view showing the fitting of a connecting tube and an opening device in embodiment 2 of the present invention;

fig. 7 is a schematic view of a battery case in embodiment 3 of the invention;

fig. 8 is a schematic structural view of an opening device in embodiment 3 of the present invention.

Reference numerals are as follows: the explosion-proof shell comprises a shell body 1, an upper cover assembly 2, a connecting pipe 3, a sealing film 4, an opening device 5, a liquid storage pipe 6, a sliding rod 7, an explosion venting device 8, an opening 11, a through hole 31, a nick 41, a wedge surface 51 and a positioning boss 52.

Detailed Description

The present invention will be described in detail below with reference to the accompanying drawings and specific embodiments. It should be understood by those skilled in the art that these embodiments are only for explaining the technical principle of the present invention and are not intended to limit the scope of the present invention.

The invention provides a battery shell, a battery and a high-capacity battery for solving the problem of the consistency of the working environments of all electrode assemblies forming the high-capacity lithium ion battery, which can share the electrolyte in all the electrode assemblies, achieve the aim of uniform and consistent electrolyte performance and further prolong the service life of the battery. Meanwhile, the arrangement can effectively prevent the battery shell from contacting with water vapor in the air when the battery shell is opened, the operation method is simple and reliable, the water vapor is well isolated, other manufacturing processes of the battery are not increased, the operability is strong, and the battery is economical and practical.

The shell body of the battery shell is provided with an opening, the opening is provided with a connecting pipe, a sealing film is arranged in the connecting pipe or the opening of the shell body, and the sealing film seals the battery shell to prevent electrolyte in the battery shell from contacting water vapor in the air. When the electrolyte is injected to realize sharing, the sealing film needs to be opened, and attention needs to be paid to avoiding contact with moisture in the air when the sealing film is opened. Based on this, the sealing membrane is opened by external acting force or external pressure in the connecting pipe, and the opening mode is simple to operate and good in moisture isolation. The present invention is not limited to the structure for applying an external force or an external pressure, as long as the sealing film can be opened while avoiding contact with air. The manner of opening the sealing film or the opening device will be described in detail below.

Example 1

As shown in fig. 1 and fig. 2, the battery case provided in this embodiment includes an upper cover assembly 2, a case body 1 and a liquid injection assembly, where the case body 1 is a case structure with an open end, and the upper cover assembly 2 and the case body 1 enclose to form the battery case; the housing body 1 is provided with an opening 11 communicated with the inner cavity thereof. Annotate the liquid subassembly and include connecting pipe 3 and seal membrane 4, connecting pipe 3 sets up on casing body 1, and through opening 11 and 1 inner chamber intercommunication of casing body, this connecting pipe 3 can with 1 integrative settings of casing body, also can with casing body 1 welding or through flange sealing connection. The sealing film 4 is provided in the opening 11 of the case body 1 to seal the case body 1 from the electrolyte inside the battery case coming into contact with the outside air.

After a plurality of batteries are connected in parallel to form a large-capacity battery, the batteries need to be in a uniform electrolyte system, the sealing film 4 needs to be opened, at the moment, the connecting pipe 3 is externally connected with an air source, the air source fills high-pressure gas, such as inert gas like nitrogen, into the connecting pipe 3, and the sealing film 4 is broken and opened under the pressure action of the high-pressure gas. This way, contact with moisture or impurities in the air can be avoided during the opening of the sealing film 4. Can be connected connecting pipe 3 and the liquid storage pipe of a plurality of battery shells through the butt joint spare, pour into electrolyte into the battery shell through the liquid storage pipe in to the battery shell, electrolyte is from the outside inside injection of battery shell through annotating the liquid subassembly to inside, so that electrolyte gets into inside the battery shell, the intercommunication is realized to electrolyte in a plurality of batteries, makes a plurality of batteries be in the electrolyte system of homogeneity, thereby increases substantially the uniformity of each electrode subassembly energy storage performance, and improves battery performance and yield and life.

In this embodiment, the sealing film 4 is made of at least one of copper, aluminum, PP, PE, and teflon. As shown in fig. 3, in order to allow the sealing film 4 to be opened rapidly, a score 41 may be provided on the sealing film 4, and the sealing film 4 may be opened at the score 41. Meanwhile, the sealing film 4 is arranged on one side, away from the upper cover assembly 2, of the shell body 1, the upper cover assembly 2 is provided with a positive pole column and a negative pole column, after electrolyte in the batteries are communicated with each other, when a large-capacity battery is used, the upper cover assembly 2 is arranged upwards, and the liquid storage pipe and the connecting pipe 3 are arranged downwards.

Example 2

As shown in fig. 4 to fig. 6, the battery case provided in this embodiment includes an upper cover assembly 2, a case body 1 and a liquid injection assembly, where the case body 1 is a case structure with an open end, and the upper cover assembly 2 and the case body 1 enclose to form the battery case; an opening communicated with the inner cavity of the shell body 1 is arranged on the shell body; annotate the liquid subassembly and include connecting pipe 3 and seal membrane, connecting pipe 3 sets up on casing body 1, and through opening and 1 inner chamber intercommunication of casing body, this connecting pipe 3 can with 1 integrative settings of casing body, also can with 1 welding of casing body or through flange sealing connection. A sealing film is provided in the connection tube 3 to seal the battery case. Be provided with opening device 5 in this connecting pipe 3, opening device 5 has the structure that backs down the arch or backs down the spine, one end sets up the round platform for one end, the size of this round platform and the internal diameter phase-match of connecting pipe 3, the diameter of round platform is the same with the internal diameter of connecting pipe 3 or the diameter of round platform slightly is less than the internal diameter of connecting pipe 3 promptly for opening device 5 can remove in connecting pipe 3 under the effect of outside pressure. When the opening device 5 moves, the top opening bulge or the top opening spike of the opening device 5 can open the sealing film, so that the sealing film is opened, and the electrolyte injection is realized. Meanwhile, the center of the sealing film can be provided with a nick, and the top opening bulge or the top opening sharp of the opening device 5 opens the nick, so that the sealing film can be opened quickly.

When parallelly connected constitution large capacity battery of a plurality of batteries, when needing to be in the electrolyte system of homogeneous with a plurality of batteries, open above-mentioned seal membrane, electrolyte is from the outside internal injection of battery case through annotating the liquid subassembly, the external air supply of connecting pipe 3, the air supply is filled high-pressure gas in to connecting pipe 3, for example, inert gas such as nitrogen gas, opening device 5 removes in connecting pipe 3 under high-pressure gas's pressure effect, opening device 5 opens the seal membrane, this kind of structure avoid with steam or impurity contact in the air at the in-process that the seal membrane was opened. Subsequently, the connecting pipes 3 and the liquid storage pipes 6 of the plurality of battery shells can be connected through the butt-joint piece, and electrolyte is filled into the battery shells through the liquid storage pipes 6, so that the electrolyte enters the interior of the battery shells, the electrolytes in the plurality of batteries are communicated, and the plurality of batteries are positioned in a uniform electrolyte system, so that the consistency of the energy storage performance of each electrode assembly is greatly improved, and the performance, the yield and the service life of the batteries are improved.

In order to prevent the opening means 5 from being connected to the sealing membrane and not being able to be separated after opening the sealing membrane, -40mmHg is applied in the connecting tube 3, a pressure difference is created between the two sides of the opening means 5, the opening means 5 is sucked from the sealing membrane in the opposite direction, and if the opening means 5 has been separated from the sealing membrane, the opening pierced in the sealing membrane can be further expanded by the pressure difference of the negative pressure suction. And after the negative pressure suction is finished, the electrolyte is recharged. Therefore, the battery cores are ensured to be soaked in the electrolyte together, and the internal environments of the electrode assemblies are communicated into a whole. The electric performance of each electrode assembly is ensured to be the same, and the working environment and the electrolyte soaking environment are also ensured to be the same, so that the consistency of the electric performance and the working condition of all the electrode assemblies is ensured, and the service life of a large-capacity battery is greatly prolonged.

In this embodiment, the opening device 5 opens the sealing film of the battery to communicate the electrolyte under the action of the external pressure. As shown in fig. 6, the opening unit 5 is disposed in the connection tube 3, and a positioning boss 52 is formed in the tube, and the positioning boss 52 serves to limit the opening unit 5, ensuring that the opening unit 5 can open the sealing film without damaging the electrode assembly. When the opening means 5 opens the sealing membrane, the opening means 5 may be sized smaller than the diameter of the connecting pipe so that the electrolyte is circulated from the gap between the opening means and the connecting pipe. Alternatively, when the connection tube 3 is connected to the liquid storage tube, the connection tube 3 partially extends into the liquid storage tube. At this moment, the through hole 31 can be formed in the connecting pipe 3 extending to the inside of the liquid storage pipe, after the opening device 5 opens the sealing film, the opening device 5 falls back to the bottom of the connecting pipe 3, at this moment, the opening device 5 possibly blocks the bottom of the connecting pipe 3, electrolyte cannot flow in from the bottom of the connecting pipe 3, at this moment, electrolyte can be injected in the circumferential direction through the through hole 31, and electrolyte sharing among battery packs is ensured, at this moment, of course, the thickness of the circular truncated cone of the opening device 5 needs to be smaller than the pipe diameter of the liquid storage pipe, and the circular truncated cone is located below the through hole 31, so that the through hole 31 is not blocked.

Example 3

As shown in fig. 3 and fig. 7, the battery case provided in this embodiment includes an upper cover assembly 2, a case body 1 and a liquid injection assembly, where the case body 1 is a case structure with an open end, and the upper cover assembly 2 and the case body 1 enclose to form the battery case; an opening 11 communicated with the inner cavity of the shell body 1 is formed in the shell body; annotate the liquid subassembly and include connecting pipe 3 and seal membrane, and connecting pipe 3 sets up on casing body 1, and through

opening

11 and 1 inner chamber intercommunication of casing body, and this connecting pipe 3 can set up with casing body 1 is integrative, also can weld or pass through flange joint with casing body 1. The sealing film 4 is provided in the opening 11 of the case body 1 or in the connection tube 3 to seal the battery case. Be provided with opening device 5 in the connecting pipe 3, opening device 5 has for one end and backs down the arch or backs down the spine, one end sets up the structure of round platform, opening device 5 can remove in connecting pipe 3 under external effort, make opening device 5 open seal membrane 4, this kind of opening mode is mechanical opening mode, lean on external mechanical strength to open seal membrane 4, can be provided with slider in stock solution pipe 6, slider is slide bar 7, slide bar 7 promotes opening device 5 and slides in connecting pipe 3, make opening device 5 open seal membrane 4. In order to allow a better circulation of the electrolyte after the opening device 5 has been pushed open, the opening device 5 can be a hollow opening device, in which a through-channel is provided in the interior thereof in the direction of movement thereof, through which the electrolyte enters the battery housing. As shown in fig. 8, in order to move the opening device 5 quickly and accurately, the end surface of the opening device 5 that is engaged with the sliding device is provided with a wedge surface 51.

When electrolyte is injected from the outside of the battery shell to the inside through filling the liquid assembly, the operation is carried out under the environment of a sealed box body or a dry box body, the sliding rod 7 is pushed to slide in the liquid storage pipe 6, the hollow opening device is pushed to the sealing film 4, the sealing film 4 is opened, so that the electrolyte enters the battery shell, and the structure avoids the contact with steam or impurities in the air in the process of opening the sealing film 4. The sealing film 4 is made of at least one of copper, aluminum, PP, PE and polytetrafluoroethylene.

Example 4

As shown in fig. 3 and 7, the battery case provided in this embodiment includes an upper cover assembly 2, a case body 1 and a liquid injection assembly, where the case body 1 is a case structure with an open end, and the upper cover assembly 2 and the case body 1 enclose to form the battery case; an opening 11 communicated with the inner cavity of the shell body 1 is arranged on the shell body; annotate the liquid subassembly and include connecting pipe 3 and seal membrane, connecting pipe 3 sets up on casing body 1, and through

opening

11 and 1 inner chamber intercommunication of casing body, this connecting pipe 3 can with 1 integrative settings of casing body, also can with 1 welding of casing body or through flange joint. The material of this seal membrane is the same with the material of casing body, and seal membrane and the integrative setting of casing body, and the thickness of seal membrane is less than the wall thickness of casing body for the seal membrane is the weak part of casing body, and perhaps the material of this seal membrane is the same with the material of casing body, and seal membrane and the integrative setting of casing body are provided with the nick on the seal membrane, make the seal membrane be the weak part of casing body. Be provided with opening device 5 in the connecting pipe 3, opening device 5 has the top for one end and opens the arch, one end sets up the structure of round platform, opening device 5 can remove in connecting pipe 3 under outside effort, make opening device 5 open seal membrane 4, this kind of opening mode is mechanical opening mode, lean on external mechanical strength to open seal membrane 4, can be provided with slider in stock solution pipe 6, slider is slide bar 7, slide bar 7 promotes opening device 5 and slides in connecting pipe 3, make opening device 5 break seal membrane 4. In order to allow a better circulation of the electrolyte after the opening device 5 has been pushed open, the opening device 5 can be a hollow opening device, in which a through-channel is provided in the interior thereof in the direction of movement thereof, through which the electrolyte enters the battery housing. In addition, the sliding rod also occupies space, and the using amount of electrolyte is reduced. As shown in fig. 8, for a quick and accurate movement of the opening means 5, the end surfaces of the opening means 5 cooperating with the sliding means are provided with wedge surfaces 51.

When electrolyte is injected from the outside of the battery shell to the inside through annotating the liquid subassembly, at sealed box environment operation, promote slide bar 7 and slide in liquid storage pipe 6, push hollow opening device to seal membrane 4, open seal membrane 4 to inside making electrolyte get into the battery shell, this kind of structure avoids contacting with steam or impurity in the air at the in-process that seal membrane 4 was opened. The sealing film 4 is made of at least one of copper, aluminum, PP, PE and polytetrafluoroethylene.

Example 5

As shown in fig. 5 and 7, the present embodiment provides a battery including the battery case of embodiment 1, embodiment 2, or embodiment 3, and an electrode assembly soaked with an electrolyte in the battery case. The embodiment also provides a large capacity battery, including liquid storage pipe 6 and above-mentioned battery, liquid storage pipe 6 all communicates with a plurality of battery case's connecting pipe 3. Before the battery is formed into a large-capacity battery, the capacitance, the internal resistance and the charge-discharge characteristics of each electrode assembly are tested, and the error of the three parameters of each electrode assembly is within 1 percent, so that the electrode assemblies can be matched with one another. The connecting pipe 3 is communicated with the liquid storage pipe 6 through a butt joint piece. After the sealing membrane is opened, electrolyte is poured into the battery shell through the liquid storage pipe 6, so that the electrolyte enters the battery shell, the electrolyte in the batteries is communicated, the batteries are in a uniform electrolyte system, the consistency of the energy storage performance of each electrode assembly is greatly improved, the battery performance and the yield are improved, and the service life is prolonged.

The sealing membrane is opened by external acting force or external pressure in the connecting pipe, the sealing membrane can be opened in a state of avoiding contact with air in the mode, the contact with water vapor in the air when the battery shell is opened can be effectively prevented, the operation method is simple and reliable, the water vapor isolation is good, other manufacturing processes of the battery are not increased, the operation is convenient, the performance and the yield of the battery are improved, the structure is simple, the installation is simple and convenient, the universality is strong, and the sealing membrane is opened by the mode

In addition, as shown in fig. 5, an explosion venting device 8 may be further disposed on the liquid storage pipe 6 to vent out flue gas generated when the large-capacity battery is out of thermal control, and the explosion venting device 8 may specifically be an explosion venting valve.

Claims

1. A battery case, comprising:

an upper cover assembly;

the upper cover assembly and the shell body are enclosed to form a battery shell; the shell body is provided with an opening communicated with the inner cavity of the shell body; and

the liquid injection assembly comprises a connecting pipe and a sealing film, and the connecting pipe is arranged on the shell body and is communicated with the inner cavity of the shell body through an opening; the sealing membrane is arranged in the opening of the shell body or in the connecting pipe so as to seal the battery shell;

when electrolyte passes through annotate the subassembly and annotate from the casing body outside to inside, the seal membrane passes through the interior external force of connecting tube or external pressure and opens, so that electrolyte gets into in the casing body.

2. The battery case according to claim 1, wherein an opening device is provided in the connection tube, the opening device being movable within the connection tube under the action of external pressure or a sliding device, such that the opening device opens the sealing film.

3. The battery case according to claim 2, wherein the opening means has an ejecting protrusion or an ejecting spike at one end and a truncated cone at the other end.

4. The battery case of claim 3, wherein the diameter of the circular truncated cone is equal to or less than the inner diameter of the connection tube and a pressure difference can be generated between both sides of the circular truncated cone when the opening device moves in the connection tube under an external pressure.

5. The battery housing as recited in claim 3, wherein the frustoconical side wall of the opening device is provided with a wedge surface, the wedge surface being adapted to cooperate with the sliding device to achieve rapid and accurate movement of the opening device.

6. The battery case according to any one of claims 2 to 5, wherein a plurality of through holes are circumferentially provided on a side wall of one end of the connecting tube away from the opening for circumferential injection of the electrolyte.

7. A battery housing according to claim 5, characterized in that the inside of the opening means is provided with a passage therethrough in the direction of movement thereof.

8. The battery case according to claim 2, wherein a positioning boss for limiting the opening means is provided on the inner wall of the connection tube such that the opening means can open the sealing film without damaging the electrode assembly inside the battery case.

9. The battery case according to claim 1 or 2, wherein the sealing film is made of the same material as that of the case body, the sealing film is integrally provided with the case body, and the thickness of the sealing film is smaller than the wall thickness of the case body.

10. The battery case according to claim 1 or 2, wherein the sealing film is made of the same material as the case body, the sealing film is integrally formed with the case body, and the sealing film is provided with a notch for realizing rapid rupture of the sealing film.

11. The battery shell according to claim 1 or 2, wherein the sealing film is provided with a score for realizing quick opening of the sealing film, and the sealing film is made of at least one of copper, aluminum, PP, PE and polytetrafluoroethylene.

12. The battery case according to claim 1 or 2, wherein the opening is provided at a side of the case body away from the upper cover assembly.

13. A battery comprising an electrode assembly and the battery case according to any one of claims 1 to 12, wherein the electrode assembly is disposed in the battery case and is soaked with an electrolyte.

14. A large capacity battery comprising a plurality of batteries according to claim 13 and a reservoir tube communicating with each of the connecting tubes of the plurality of battery cases.

15. A large capacity battery as claimed in claim 14, wherein a sliding means is provided in the reservoir tube, the sliding means being a sliding rod for pushing the opening means to slide within the connecting tube so that the opening means opens the sealing film.

16. A large capacity battery as defined in claim 14, wherein a liquid injection means is provided on the reservoir tube, and the liquid injection means is a liquid injection valve.

17. The high-capacity battery as claimed in claim 14, wherein the liquid storage pipe is further provided with an explosion venting device to vent out smoke generated when the high-capacity battery is out of thermal runaway, and the explosion venting device is an explosion venting valve.