Lithium battery exhaust device

Abstract

The utility model discloses an exhaust device for a lithium battery, which belongs to the technical field of batteries and comprises an exhaust valve and a safety valve, the safety valve comprises a shell, an opening for the exhaust valve to be led in is arranged below the shell, at least two groups of stretching components are arranged in the shell, each stretching component comprises an elastic part A and a piston, and the elastic part A is connected with the piston. One end of the elastic piece A is connected with the inner wall of the shell, the other end of the elastic piece A is connected with the piston, the stretching assemblies are connected through the elastic piece B, and exhaust holes are formed in the shell at the stretching assemblies. A baffle is further arranged in the exhaust cavity and located on the side, close to the elastic piece B, of the piston, and the piston stays at the position of the exhaust hole through the baffle. By arranging the stretching assembly connected with the elastic pieces, when one elastic piece in the exhaust device breaks down, the exhaust device can still work under the action of the other elastic piece, the error-tolerant rate of the exhaust device is improved, and the safety of the battery in the using process is further improved.

Description

Technical Field

[0001] The utility model belongs to the field of batteries, and more specifically, relates to a lithium battery exhaust device. Background Art

[0002] With the decreasing fossil fuel energy, the traditional fuel vehicle industry has also been seriously affected. The importance of the new energy vehicle industry has become increasingly prominent, and lithium batteries are the most important part of new energy vehicles. High energy density, long cycle life and high safety performance are the primary choices for lithium batteries in new energy vehicles. Lithium batteries are composed of positive electrodes, negative electrodes, diaphragms and electrolytes. The positive and negative electrodes are separated by diaphragms to form a battery pack. The battery pack is placed in the shell, the electrolyte is injected and the battery is sealed. Lithium batteries will generate gas during production and abnormal use. The assembly of exhaust devices can effectively exhaust gas and improve the safety performance of lithium batteries.

[0003] The gas production of lithium batteries is mainly normal gas production and abnormal gas production. Normal gas production refers to the gas produced when current is applied to form the SEI film during the formation process. Abnormal gas production is the gas produced after the battery is packaged due to short circuit, overcharging, temperature rise, and moisture. Abnormal gas production will cause pressure to increase. If the gas cannot be discharged in time, it will cause the shell to expand or even explode.

[0004] After searching, patent CN105006537A discloses a cover plate of a lithium-ion power battery, including a cover plate, an exhaust cavity is provided in the cover plate, a bent exhaust channel is provided on the cover plate, a lower port of the exhaust channel is communicated with the interior of the battery, an upper port of the exhaust channel is located at the side wall of the exhaust cavity and communicates with the exhaust cavity, a piston is provided in the exhaust cavity, a sealing ejector pin is provided on the piston for blocking the upper port of the exhaust channel, a compression spring is provided between the piston and the side wall of the exhaust cavity, one end of the compression spring is mounted on the piston and the other end is fixed to the side wall of the exhaust cavity, an exhaust hole is provided on the cover plate, and when the sealing ejector pin blocks the upper port of the exhaust channel, the exhaust hole is blocked by the side of the piston.

[0005] Chinese patent CN105006537A discloses a cover plate of a lithium-ion power battery, including a cover plate, wherein an exhaust cavity is provided in the cover plate, a bent exhaust channel is provided on the cover plate, a lower port of the exhaust channel is communicated with the interior of the battery, an upper port of the exhaust channel is located at a side wall of the exhaust cavity and communicates with the exhaust cavity, a piston is provided in the exhaust cavity, a sealing ejector pin for blocking the upper port of the exhaust channel is provided on the piston, a compression spring is provided between the piston and the side wall of the exhaust cavity, one end of the compression spring is attached to the piston and the other end is fixed to the side wall of the exhaust cavity, an exhaust hole is provided on the cover plate, and when the sealing ejector pin blocks the upper port of the exhaust channel, the exhaust hole is blocked by the side of the piston.

[0006] All of the above are controlled by a spring to exhaust. When the spring fails, exhaust cannot be performed, and the fault tolerance rate is low. High fault tolerance rate and long service life cannot be guaranteed. Summary of the invention

[0007] 1. Problems to be solved

[0008] Aiming at the problem of low fault tolerance of existing lithium battery exhaust devices, the utility model provides a lithium battery exhaust device.

[0009] 2. Technical solution

[0010] To solve the above problems, the utility model adopts the following technical solutions.

[0011] A lithium battery exhaust device comprises an exhaust valve and a safety valve. The safety valve comprises a shell, and an opening for the exhaust valve to pass through is provided below the shell.

[0012] Furthermore, the shell includes a buffer cavity and exhaust cavities whose number matches the number of the stretching components, the buffer cavity and the exhaust cavity are connected, and the exhaust cavities are symmetrically arranged.

[0013] Furthermore, a plurality of through holes are provided on the exhaust valve, and the gas reaches the interior of the shell through the through holes.

[0014] At least two groups of stretching components are arranged in the shell, and the stretching components are connected by elastic members B. The stretching components are located in the exhaust cavity.

[0015] The stretching assembly includes a spring A and a piston, one end of the elastic member A is connected to the inner wall of the exhaust chamber, and the other end is connected to the piston, and the pistons are connected through an elastic member B. The connection sequence is: housing - spring A - piston - spring B - piston - spring A - housing.

[0016] Furthermore, the elastic member A is welded to the housing, and the piston is welded to the elastic member A and the elastic member B.

[0017] An exhaust hole is provided at the contact point between the piston and the shell. The diameter of the exhaust hole is preferably 0.625 times the width of the piston. The specific width can also be adjusted during actual use to ensure a certain aperture size to ensure smooth discharge of produced gas. When the air pressure in the shell is balanced, the piston blocks the exhaust hole. When the air pressure in the valve rises and the piston moves under the action of the elastic member A, the gas is discharged through the exhaust hole.

[0018] Furthermore, the surface of the through hole and the exhaust hole of the exhaust valve is covered with a dustproof, waterproof and breathable membrane, and the material of the dustproof, waterproof and breathable membrane can be polytetrafluoroethylene, or other dustproof, waterproof and breathable membranes can be used to isolate the discharge of electrolyte and the entry of external dust and moisture into the battery. The connection method between the dustproof, waterproof and breathable membrane and the shell is ultrasonic welding and adhesive bonding. The shape of the through hole and the exhaust hole of the exhaust valve can be round, square, or other shapes that do not affect the discharge of gas.

[0019] Furthermore, a baffle is provided on the side of the piston close to the elastic member B, and the piston is stopped at the exhaust hole by the baffle. When the piston reaches the baffle, the exhaust hole is closed by the piston and is not connected to the outside air.

[0020] Furthermore, the elastic member A and the elastic member B may be springs, or other elastically connectable components.

[0021] In the device of the utility model, when the internal pressure of the lithium battery increases, the gas enters the safety valve through the exhaust valve. As the gas is gradually discharged, the pistons on the left and right sides squeeze the elastic part A, open the exhaust hole, and connect it to the outside world, and the gas is discharged out of the shell. After the pressure is reduced, the piston returns to its original position. When the left and right elastic parts A malfunction and cannot work, the gas can still be discharged, and the piston position is restored by the middle elastic part B. When the middle elastic part B malfunctions and cannot work, the piston is moved by the action of the elastic part A, and when the gas is discharged, it returns to its original position under the action of the air pressure in the left and right chambers. The fault tolerance of the exhaust device is improved, thereby improving the safety of the battery during use.

[0022] The device can be applied to cylindrical, square shell, soft pack and other battery fields.

[0023] 3. Beneficial effects

[0024] Compared with the prior art, the beneficial effects of the utility model are:

[0025] (1) The lithium battery exhaust device of the utility model is provided with a stretching assembly connected by elastic parts. When one elastic part in the exhaust device fails, the exhaust device can continue to work through the action of another elastic part, thereby improving the fault tolerance of the exhaust device and further improving the safety of the battery during use;

[0026] (2) The lithium battery exhaust device of the utility model is provided with a baffle to stop the piston at the exhaust hole to prevent the piston from being misplaced;

[0027] (3) In the lithium battery exhaust device of the present invention, the through hole of the exhaust valve and the surface of the exhaust hole are covered with a dustproof, waterproof and breathable film to prevent the discharge of electrolyte and the entry of external dust and moisture into the battery. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The technical solution of the utility model will be further described in detail below in conjunction with the accompanying drawings and embodiments, but it should be understood that these drawings are designed only for the purpose of explanation and are not intended to limit the scope of the utility model. In addition, unless otherwise specified, these drawings are only intended to conceptually illustrate the structural configurations described herein and are not necessarily drawn to scale.

[0029] Figure 1 This is a main cross-sectional view of the overall structure of the lithium battery exhaust device of the utility model;

[0030] Figure 2 This is a top view of the overall structure of the lithium battery exhaust device of the utility model;

[0031] Figure 3 This is a side view of the overall structure of the lithium battery exhaust device of the utility model;

[0032] In the figure: 100, safety valve; 110, housing; 111, buffer chamber; 112, exhaust chamber;

[0033] 120, stretching assembly; 121, piston; 122, elastic member A; 130, elastic member B; 140, exhaust hole; 150, baffle;

[0034] 200, exhaust valve; 210, through hole. DETAILED DESCRIPTION

[0035] The following detailed description and example embodiments of the present invention may be better understood in conjunction with the accompanying drawings, in which elements and features of the present invention are identified by reference numerals.

[0036] Example 1

[0037] like Figure 1-3 As shown, a lithium battery exhaust device includes an exhaust valve 200 and a safety valve 100. The safety valve 100 includes a housing 110. The housing 110 is a T-shaped housing 110, which includes a buffer chamber 111 and exhaust chambers 112 matching the number of the stretching components 120. The buffer chamber 111 is connected to the exhaust chamber 112, and the exhaust chambers 112 are symmetrically arranged. An opening for the exhaust valve 200 to pass through is provided below the housing 110. Four annular through holes 210 for exhaust are provided on the exhaust valve 200, which are covered with a circle of dustproof, waterproof and breathable membrane. When gas is generated inside the lithium battery, the gas passes through the through holes 210 on the exhaust valve 200 to reach the inside of the housing 110.

[0038] At least two groups of stretching components 120 are arranged in the housing 110, and the stretching components 120 are connected by springs B 130. The stretching components 120 are located in the exhaust chamber 112, and each exhaust chamber 112 is provided with a stretching component 120. The stretching components 120 include springs A 122 and pistons 121, one end of the spring A 122 is connected to the inner wall of the exhaust chamber 112, and the other end is connected to the pistons 121, and the pistons 121 are connected by springs B 130. The spring A 122 is welded to the housing 110, and the piston 121 is welded to the springs A 122 and B 130. An exhaust hole 140 is provided at the contact point between the piston 121 and the housing 110, and the exhaust hole 140 is a circular hole with a diameter of 0.625 times the width of the piston 121, and the circular hole is covered with a square dustproof, waterproof and breathable membrane. When the air pressure in the shell is balanced, the piston 121 blocks the exhaust hole 140 . When the air pressure in the valve rises, the piston 121 moves under the action of the spring A122 , and the gas is discharged through the exhaust hole 140 .

[0039] To prevent the piston 121 from being misplaced, a baffle 150 is provided on the side of the piston 121 close to the spring B 130, so that the piston 121 stays at the exhaust hole 140. When the piston 121 reaches the baffle 150, the exhaust hole 140 is closed by the piston 121 and is not connected to the outside air.

[0040] In Example 1, the dustproof, waterproof and breathable membrane is made of polytetrafluoroethylene, which isolates the discharge of electrolyte and prevents external dust and moisture from entering the battery.

[0041] When in working state, the gas generated inside the lithium battery is discharged through the exhaust valve 200. The pressure inside the safety valve 100 is too high, pushing the two pistons 121 to slide to the left and right sides respectively. At this time, the exhaust hole 140 on the safety valve 100 is connected to the outside, and the gas is discharged smoothly.

[0042] The utility model has a high fault tolerance rate and a long service life. When the spring A122 fails, the gas is discharged into the housing 110. At this time, the piston 121 can still be pushed to open the exhaust hole 140 to exhaust smoothly. After the exhaust is completed, under the action of the spring B 130, the piston 121 can still return to its original position and close the exhaust hole 140. Due to the presence of the baffle 150, the piston 121 without the traction of the spring A122 can be effectively prevented from being misplaced. If the spring B 130 fails, the spring A122 can still open the piston 121 under the action of the air pressure. After the exhaust is completed, the piston 121 returns to its original position under the action of the air pressure and is prevented from being misplaced by the baffle 150. The utility model connects two pistons 121 by three springs, which greatly improves the fault tolerance rate and service life of the exhaust device, so that the safety valve 100 can continue to operate in the case of partial failure.

[0043] It is obvious to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be regarded as exemplary and non-restrictive from any point of view, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention. Any reference numeral in a claim should not be regarded as limiting the claim to which it relates.

[0044] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A lithium battery exhaust device, comprising an exhaust valve (200) and a safety valve (100), wherein the safety valve (100) comprises a housing (110), and an opening for the exhaust valve (200) to pass through is provided below the housing (110), characterized in that: At least two groups of stretching components (120) are arranged in the shell (110), and the stretching components (120) are connected by elastic members B (130). An exhaust hole (140) is provided on the shell (110) at the stretching components (120).

2. The lithium battery exhaust device according to claim 1, characterized in that: The housing (110) comprises a buffer chamber (111) and exhaust chambers (112) whose number matches the number of the stretching components (120); the buffer chamber (111) and the exhaust chamber (112) are in communication.

3. The lithium battery exhaust device according to claim 2, characterized in that: The stretching assembly (120) comprises an elastic member A (122) and a piston (121); one end of the elastic member A (122) is connected to the inner wall of the exhaust chamber (112), and the other end is connected to the piston (121).

4. The lithium battery exhaust device according to claim 3, characterized in that: The elastic member A (122) is welded to the housing (110), and the piston (121) is welded to the elastic member A (122) and the elastic member B (130).

5. The lithium battery exhaust device according to claim 3, characterized in that: The exhaust hole (140) is provided at the contact point between the piston (121) and the housing (110), and is located at the position of the piston (121) when the air pressure in the housing is balanced.

6. The lithium battery exhaust device according to claim 5, characterized in that: A baffle (150) is also provided in the exhaust chamber (112). The baffle (150) is located on a side of the piston (121) close to the elastic member B (130). The piston (121) stays at the exhaust hole (140) through the baffle.

7. The lithium battery exhaust device according to claim 1, characterized in that: The exhaust hole (140) is covered with a dustproof, waterproof and breathable membrane.

8. The lithium battery exhaust device according to claim 7, characterized in that: The dustproof, waterproof and breathable membrane is connected to the housing (110) by ultrasonic welding and adhesive bonding.

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