Negative pressure formation device of battery

Abstract

The utility model discloses a negative pressure formation device of a battery, and belongs to the technical field of secondary batteries. Comprising a cup body provided with a cup body air guide hole; the sealing assembly is connected with the cup body and used for abutting against the battery cell top cover, a sealing air guide hole is formed in the sealing assembly, the sealing air guide hole and the cup body air guide hole are located on the same axis and communicate with each other, and the sealing air guide hole is used for communicating with a liquid injection hole formed in the battery cell top cover; the liquid blocking breathable film is arranged in the sealing assembly, and the liquid blocking breathable film is used for allowing gas to pass through and blocking liquid. The liquid-blocking breathable film ensures that gas generated in the formation process is exhausted in the negative pressure formation process, and electrolyte in the shell is prevented from being pumped out, so that the risk of formation liquid loss and the risk that the electrolyte is pumped to the cup body by negative pressure to be subjected to secondary pollution are reduced.

Description

TECHNICAL FIELD

[0001] The utility model belongs to secondary battery technical field, concretely relates to a negative pressure formation device of battery. BACKGROUND

[0002] In the production process of lithium ion battery, the lithium ion battery of square shell packaging needs to pass through the formation process to activate the battery after injection. The formation process is to form SEI film (solid electrolyte interface film) in the battery, which can realize ion conduction and electron barrier on the surface of the pole piece, thereby ensuring the normal work of the lithium ion battery.

[0003] However, in the process of forming SEI film, a series of side reactions will occur, and a large amount of gas will be generated. If these gases cannot be discharged in time, they will accumulate between the pole pieces, affecting the conduction efficiency of lithium ions, and eventually causing black spots on the surface of the negative pole piece and forming lithium precipitation on the edge, which not only reduces the performance of the battery, but also brings safety hazards.

[0004] At present, in order to discharge the gas generated in the formation process, two methods are usually used: pressurizing the battery surface body or extracting negative pressure in the shell. However, for square shell batteries, due to the use of less than 100% shell margin, it is difficult to effectively extrude the bubbles between the pole pieces by simply pressurizing the battery body, so the more common method is to extract negative pressure in the shell.

[0005] In the existing negative pressure formation process of square shell battery, a negative pressure cup is generally used to press and seal the battery injection port and implement the negative pressure extraction action. However, this method has some obvious problems:

[0006] 1. When the bubbles in the shell expand under negative pressure, the electrolyte near the injection port will be squeezed out into the liquid storage cup and return to the shell during the discharge of the bubbles in the shell, which may cause liquid loss during formation and the risk of secondary pollution of the electrolyte extracted by negative pressure into the cup.

[0007] 2. Since the battery is extremely sensitive to moisture, the liquid storage cup needs to be kept dry, and it needs to be cleaned after each use. However, due to its difficult disassembly, it is difficult to get sufficient cleaning and maintenance.

[0008] 3. During the idle stage of production, the electrolyte in the liquid storage cup will absorb the moisture in the air, and the electrolyte extracted by negative pressure will be brought into the shell during the next production process, which will affect the performance of the battery. INVENTION CONTENTS

[0009] The utility model is proposed to solve the above problems in the prior art, and a negative pressure formation device of battery which can extract gas and prevent electrolyte from being extracted.

[0010] The utility model discloses a following technical scheme can be realized:

[0011] A negative pressure formation device of a battery, comprising:

[0012] A cup body having a cup body air guide hole;

[0013] A sealing assembly connected to the cup body and used for abutting against a top cover of a battery cell, the sealing assembly being provided with a sealing air guide hole, the sealing air guide hole being located on the same axis as the cup body air guide hole and being in communication with the cup body air guide hole, and the sealing air guide hole being used for communicating with a liquid injection hole provided on the top cover of the battery cell;

[0014] A liquid-resistant and air-permeable membrane arranged in the sealing assembly, the liquid-resistant and air-permeable membrane being used for allowing gas to pass through and blocking liquid.

[0015] As a further improvement of the utility model, the cup body comprises a main body part and a cup body air guide part connected to each other, and the cup body air guide hole penetrates through the main body part and the cup body air guide part.

[0016] As a further improvement of the utility model, the sealing assembly comprises a pre-tightening block and a sealing nozzle, the cup body, the pre-tightening block and the sealing nozzle are connected in sequence, the pre-tightening block is provided with a pre-tightening block air guide hole, the sealing nozzle is provided with a sealing nozzle hole, and the pre-tightening block air guide hole and the sealing nozzle hole form the sealing air guide hole.

[0017] As a further improvement of the utility model, the cup body air guide hole, the pre-tightening block air guide hole and the sealing nozzle hole are located on the same axis and are in communication with each other, and the sealing nozzle hole is used for communicating with the liquid injection hole provided on the top cover of the battery cell.

[0018] As a further improvement of the utility model, the cup body comprises a main body part and a cup body air guide part connected to each other, and the cup body air guide hole penetrates through the main body part and the cup body air guide part.

[0019] As a further improvement of the utility model, a fixing support is further provided, the cup body air guide part passes through a through hole of the fixing support and is connected to the pre-tightening block, and both ends of the fixing support are fixed to an external device and can move up and down with the action of the device.

[0020] As a further improvement of the utility model, a spring is further provided, the spring is sleeved on the cup body air guide part, and both ends of the spring are respectively in abutment with the fixing support and the pre-tightening block.

[0021] As a further improvement of the utility model, the upper end surface of the pre-tightening block is provided with a first connecting groove recessed inward, and the lower end surface of the pre-tightening block is provided with a pre-tightening air guide part protruding outward, the cup body air guide part is inserted into the first connecting groove and is connected to the pre-tightening air guide part through threads.

[0022] As a further improvement of the utility model, the insertion end face of the cup body air guide part is provided with a rubber pad between the bottom face of the first connecting groove.

[0023] As a further improvement of the utility model, the upper end face of the sealing nozzle is provided with a second connecting groove concavely arranged, and the pre-tightening air guide part is inserted into the second connecting groove and elastically interference-fitted therebetween.

[0024] As a further improvement of the utility model, the main body part is provided, at one end away from the cup body air guide part, with an air pipe joint for connecting with an external negative pressure device.

[0025] Compared with the prior art, the utility model has the following beneficial effects:

[0026] 1. Effective air exhaust to prevent electrolyte extrusion:

[0027] The design of the liquid-blocking air-permeable membrane ensures that, in the negative pressure formation process, the gas generated in the formation process is exhausted, and the electrolyte in the shell is prevented from being extracted, thereby reducing the risk of formation liquid loss and the risk of secondary pollution of the electrolyte extracted by the negative pressure to the cup body.

[0028] 2. Simplified cleaning and maintenance process:

[0029] When the equipment is idle, the sealing nozzle can be directly pulled out for soaking cleaning or the air-permeable membrane can be cleaned with cleaning liquid, and the maintenance is simple. Since only the sealing nozzle needs to be cleaned and maintained, the entire cup body does not need to be cleaned, thereby greatly simplifying the cleaning and maintenance process and improving the maintenance efficiency.

[0030] 3. Improved production efficiency and product quality:

[0031] Through the optimized structural design, the safety and efficiency of the formation process are ensured, and the problem of battery performance degradation caused by electrolyte extrusion is avoided, thereby improving the quality of the final product.

[0032] 4. Maintaining equipment cleanliness to prevent secondary pollution:

[0033] Due to the presence of the liquid-blocking air-permeable membrane, only gas can be exhausted and liquid is blocked, which ensures the cleanliness of the equipment and prevents secondary pollution caused by the extraction of electrolyte from the shell, thereby further ensuring that the performance of the battery is not affected.

[0034] 5. Automatic adjustment and tight fit:

[0035] The design of the spring provides an automatic adjustment function, which can continuously apply a pre-tightening force during the downward movement of the fixed support, so that the pre-tightening block, the rubber pad and the sealing nozzle are tightly fitted, thereby enhancing the sealing effect. BRIEF DESCRIPTION OF DRAWINGS

[0036] Figure 1 is an exploded view of the negative pressure formation device of the utility model;

[0037] Figure 2 is a structural schematic view of the negative pressure formation device after assembly of the utility model;

[0038] Figure 3 is an exploded view of the negative pressure formation device and the top cover of the electric core of the utility model;

[0039] Figure 4 is a sectional view of the negative pressure formation device and the top cover of the electric core after assembly of the utility model;

[0040] Figure 5 is a partial sectional view of the negative pressure formation device and the top cover of the electric core after assembly of the utility model;

[0041] Figure 6 is a structural schematic view of the liquid-resistant and air-permeable film of the utility model.

[0042] In the figure, 100, cup body;101, main body part;102, cup body air guide part;1021, cup body air guide hole;110, pre-tightening block;111, pre-tightening block air guide hole;112, pre-tightening air guide part;120, sealing nozzle;121, sealing nozzle hole;130, liquid-resistant and air-permeable film;140, fixed support;150, spring;160, rubber pad;170, tracheal joint;200, top cover of electric core;210, liquid injection hole;220, explosion-proof valve. DETAILED DESCRIPTION

[0043] The following is a specific embodiment of the utility model and further describes the technical method of the utility model in combination with the drawings, but the utility model is not limited to these embodiments.

[0044] As Figures 1-6 indicated, the utility model provides a negative pressure formation device of battery, include:

[0045] Cup body 100, it has cup body air guide hole 1021;

[0046] Sealing assembly, it is connected with cup body 100 and is used to abut on top cover 200 of electric core, and sealing assembly is set up sealing air guide hole, and sealing air guide hole and cup body air guide hole 1021 are located on the same axis and communicate, and sealing air guide hole is used to with the liquid injection hole 210 set up on top cover 200 of electric core communicated;

[0047] Liquid-resistant and air-permeable film 130, it is set up in sealing assembly, and this liquid-resistant and air-permeable film 130 usually adopts the material made of electrolyte corrosion resistance, for example EPTFE, and this film allows the passing of gas small molecule, but for liquid macromolecule, plays the role of barrier.

[0048] That is, when negative pressure is introduced into the cup body 100, the negative pressure is introduced into the battery shell through the cup body air guide hole 1021 and the sealing air guide hole, at this time, the bubbles and liquid electrolyte in the battery shell are sucked outwards under the action of negative pressure, at this time, due to the arrangement of the liquid-blocking air-permeable membrane 130, the bubbles can pass through the liquid-blocking air-permeable membrane 130 and be sucked outwards, while the liquid electrolyte is blocked in the sealing assembly, when the negative pressure is stopped, the liquid electrolyte falls back into the battery shell from the liquid injection hole 210 of the top cover 200 of the battery cell.

[0049] Preferably, the sealing assembly comprises a pre-tightening block 110 and a sealing nozzle 120, the cup body 100, the pre-tightening block 110 and the sealing nozzle 120 are connected in sequence, the pre-tightening block 110 has a pre-tightening block air guide hole 111, and the sealing nozzle 120 has a sealing nozzle hole 121, at this time, the pre-tightening block air guide hole 111 and the sealing nozzle hole 121 constitute the above-mentioned sealing air guide hole.

[0050] Among them, the cup body air guide hole 1021, the pre-tightening block air guide hole 111 and the sealing nozzle hole 120 are located on the same axis and are connected, and the sealing nozzle hole 120 is used to communicate with the liquid injection hole 210 opened on the top cover 200 of the battery cell.

[0051] The specific working principle is:

[0052] When negative pressure is introduced into the cup body 100, the negative pressure is introduced into the battery shell through the cup body air guide hole 1021, the pre-tightening block air guide hole 111, the sealing nozzle hole 121 and the liquid injection hole 210 of the top cover 200 of the battery cell, at this time, the bubbles and liquid electrolyte in the battery shell are sucked outwards under the action of negative pressure, at this time, due to the arrangement of the liquid-blocking air-permeable membrane 130, the bubbles can pass through the liquid-blocking air-permeable membrane 130 and be sucked outwards, while the liquid electrolyte is blocked in the sealing nozzle hole 121;

[0053] When the negative pressure is stopped, the liquid electrolyte falls back into the battery shell from the liquid injection hole 210 of the top cover 200 of the battery cell.

[0054] It should be noted that in the existing negative pressure formation process of square shell battery, a negative pressure cup is generally used to press and seal the liquid injection port of the battery and perform negative pressure extraction action, and the current negative pressure cup, when the bubbles in the shell expand under negative pressure, the electrolyte near the liquid injection port will be squeezed out into the liquid storage cup and return to the shell during the bubble discharge process, which will have the risk of liquid loss during formation, and there is also the risk of secondary pollution of the electrolyte after being extracted into the cup by negative pressure;

[0055] In addition, since the battery is extremely sensitive to moisture, the liquid storage cup needs to be kept dry, and after each use, the existing liquid storage cup needs to be cleaned, but due to its difficult disassembly, it is difficult to get sufficient cleaning and maintenance;

[0056] And in the production idle phase, the existing electrolyte in the liquid cup will absorb the moisture in the air, and the electrolyte extracted by negative pressure in the next production process will be brought into the shell, which will affect the performance of the battery.

[0057] Compared with the existing negative pressure cup, the negative pressure formation device provided by the embodiment has at least the following advantages:

[0058] 1. Effective exhaust to prevent electrolyte extrusion:

[0059] The unique design of the liquid-blocking and air-permeable membrane 130 ensures that both the gas generated during the formation process is exhausted and the electrolyte in the shell is prevented from being extracted, reducing the risk of liquid loss during formation and the risk of electrolyte being extracted by negative pressure to the cup body 100 and being contaminated again.

[0060] 2. Simplify the cleaning and maintenance process:

[0061] When the equipment is idle, the sealing nozzle 120 can be directly pulled out for soaking cleaning or the air-permeable membrane can be cleaned with cleaning liquid, making maintenance simple. Since only the sealing nozzle 120 needs to be cleaned and maintained, the entire cup body 100 does not need to be cleaned, greatly simplifying the cleaning and maintenance process and improving maintenance efficiency.

[0062] 3. Improve production efficiency and product quality:

[0063] Through optimized structural design, the safety and efficiency of the formation process are ensured, and the problem of battery performance degradation caused by electrolyte extrusion is avoided, thereby improving the quality of the final product.

[0064]

[0065] 4. Keep the equipment clean and prevent secondary pollution:

[0066] Due to the presence of the liquid-blocking and air-permeable membrane 130, only gas can be exhausted and liquid is blocked, ensuring the cleanliness of the equipment and preventing secondary pollution caused by the extraction of electrolyte from the shell, further ensuring that the performance of the battery is not affected.

[0067] Preferably, the cup body 100 includes a main body portion 101 and a cup body air guide portion 102 connected thereto, the main body portion 101 being the main structural part of the cup body 100, and the cup body air guide portion 102 extending from the main body portion 101 and being designed for air guide function, the cup body air guide hole 1021 being through the main body portion 101 and the cup body air guide portion 102, ensuring that negative pressure can be smoothly conducted from the outside to the inside and ultimately to the battery shell.

[0068] ​Preferably, the fixed support 140 is further included, the cup air guide part 102 passes through the through hole of the fixed support 140 and is connected with the pre-tightening block 110, both ends of the fixed support 140 are fixed on the external device and can move up and down with the action of the device, the fixed support 140 is controlled to move down by the external device mechanism, the cup 100, the pre-tightening block 110 and the sealing nozzle 120 are synchronously moved down, until the sealing nozzle 120 abuts against the top cover 200 of the battery cell, and the sealing nozzle hole 121 is aligned with the liquid injection hole 210 on the top cover 200 of the battery cell, then the negative pressure extraction operation can be performed.

[0069] Preferably, the spring 150 is further included, the spring 150 is sleeved on the cup air guide part 102, and both ends of the spring 150 are respectively abutted against the fixed support 140 and the pre-tightening block 110, the spring 150 is designed to provide an automatic adjustment function, so that the pre-tightening block 110, the rubber pad 160 and the sealing nozzle 120 are tightly matched during the downward movement of the fixed support 140, and the sealing effect is enhanced. Even if the top cover 200 of the battery cell with different thicknesses or shapes is switched, the spring 150 can also ensure good contact and sealing performance.

[0070] In addition, the combination design of the fixed support 140 and the spring 150 enhances the mechanical strength and durability of the entire device. The fixed support 140 provides stable support for the device, and the spring 150 buffers the changes of external pressure, avoids damage to the components caused by excessive pressure, and prolongs the service life of the device.

[0071] Preferably, the upper end surface of the pre-tightening block 110 is provided with a first connecting groove concave arranged, and the lower end surface is provided with a pre-tightening air guide part 112 convex arranged.

[0072] The cup air guide part 102 is inserted into the first connecting groove and connected through threads, and the rubber pad 160 is arranged between the insertion end surface of the cup air guide part 102 and the bottom surface of the first connecting groove. When the threads are tightened, the rubber pad 160 is elastically deformed under pressure, providing additional sealing effect and ensuring no gas leakage during negative pressure transmission.

[0073] Meanwhile, the upper end surface of the sealing nozzle 120 is provided with a second connecting groove concave arranged, the pre-tightening air guide part 112 is inserted into the second connecting groove, and the pre-tightening air guide part 112 and the inner wall of the second connecting groove are elastically interference fitted. This fitting mode not only ensures tight contact, but also facilitates disassembly and maintenance.

[0074] It is worth mentioning that by arranging the rubber pad 160 between the cup air guide part 102 and the first connecting groove, and adopting elastic interference fitting between the pre-tightening air guide part 112 and the second connecting groove, double sealing is realized. This effectively prevents gas leakage in the negative pressure environment during the formation process, improves the sealing reliability, and ensures the efficient progress of the formation process.

[0075] In addition, the design allows the specific size of the cup air guide 102 and the pre-tightening air guide 112 to be adjusted according to different battery models to adapt to liquid injection ports of different diameters and lengths, thereby enhancing the versatility and application range of the device.

[0076] Preferably, a tracheal connector 170 is mounted at the end of the main body 101 away from the cup air guide 102, and the tracheal connector 170 is used to connect with an external negative pressure device.

[0077] In addition, the top cover 200 of the battery cell is also provided with an explosion-proof valve 220, which mainly provides a way to release pressure when the internal pressure of the battery rises to a dangerous level due to some reasons (such as overcharging, short circuit, high temperature, etc. Abnormal conditions), thereby preventing the battery from exploding or more serious physical rupture.

[0078] The technical means disclosed in the utility model scheme is not limited to the technical means disclosed in the above technical means, and also includes the technical scheme composed of any combination of the above technical features. The above is the specific implementation of the utility model, and it should be pointed out that for ordinary skilled persons in the art, without departing from the principle of the utility model, some improvements and refinements can be made, which are also considered as the protection scope of the utility model.

[0079] It should be noted that all directional indications (such as up, down, left, right, front, back, etc.) in the embodiments of the utility model are only used to explain the relative position relationship, movement condition, etc. between the components in a certain posture (as shown in the drawings), if the specific posture changes, the directional indication also changes accordingly.

[0080] In addition, the description of "one", "a", "one" and the like in the utility model is only for the purpose of description, and cannot be understood as indicating or implying the relative importance of the indicated technical features or implicitly indicating the number of the indicated technical features. Therefore, the features limited by "one" and "a" can be explicitly or implicitly included at least one of the features. In the description of the utility model, the meaning of "a plurality of" is at least two, such as two, three, etc., unless otherwise specifically limited.

[0081] In the utility model, unless otherwise specifically defined and limited, the terms "connection", "fixing" and the like should be understood broadly, for example, "fixing" can be fixed connection, or detachable connection, or integral; can be mechanical connection, or electrical connection; can be directly connected, or indirectly connected through intermediate medium; can be the internal communication of two elements or the interaction relationship of two elements, unless otherwise specifically limited. For ordinary skilled persons in the art, the specific meaning of the above terms in the utility model can be understood according to the specific situation.

[0082] In addition, the technical solutions of various embodiments of the present application can be combined with each other, but must be based on the fact that a person skilled in the art can implement it. When the combination of technical solutions appears contradictory or unachievable, it should be considered that the combination of technical solutions does not exist and is not within the protection scope required by the present application.

Claims

1. A negative pressure formation device for a battery, characterized by comprising: The application relates to a sealing assembly for a lithium battery, which comprises the following parts: a cup body with a cup body air guide hole; a sealing assembly connected with the cup body and used for abutting against a top cover of a battery cell, the sealing assembly being provided with a sealing air guide hole, the sealing air guide hole being located on the same axis as the cup body air guide hole and being in communication with the cup body air guide hole, and the sealing air guide hole being used for being in communication with a liquid injection hole provided on the top cover of the battery cell; a liquid-blocking and air-permeating film arranged in the sealing assembly, the liquid-blocking and air-permeating film being used for allowing air to pass through and blocking liquid.

2. The negative pressure formation device of a battery according to claim 1, wherein The sealing assembly comprises a pre-tightening block and a sealing nozzle, the cup body, the pre-tightening block and the sealing nozzle being connected in sequence, the pre-tightening block being provided with a pre-tightening block air guide hole, and the sealing nozzle being provided with a sealing nozzle hole, the pre-tightening block air guide hole and the sealing nozzle hole forming the sealing air guide hole.

3. The negative pressure formation device for a battery according to claim 2, wherein The cup body air guide hole, the pre-tightening block air guide hole and the sealing nozzle hole are located on the same axis and are in communication, and the sealing nozzle hole is used for being in communication with the liquid injection hole provided on the top cover of the battery cell.

4. The negative pressure formation device for a battery according to claim 2, wherein The cup body comprises a main body part and a cup body air guide part connected with each other, and the cup body air guide hole penetrates through the main body part and the cup body air guide part.

5. The negative pressure formation device for a battery according to claim 4, wherein A fixing support is further provided, the cup body air guide part passes through a through hole of the fixing support and is connected with the pre-tightening block, and the two ends of the fixing support are fixed on an external device and can move up and down along with the action of the device.

6. The negative pressure formation device for a battery according to claim 5, wherein A spring is further provided, the spring is sleeved on the cup body air guide part, and the two ends of the spring are respectively in abutment with the fixing support and the pre-tightening block.

7. The negative pressure formation device for a battery according to claim 4, wherein The upper end surface of the pre-tightening block is provided with a first connecting groove arranged in a concave mode, and the lower end surface of the pre-tightening block is provided with a pre-tightening air guide part arranged in a convex mode outward, the cup body air guide part is inserted into the first connecting groove and is connected with the first connecting groove through threads.

8. The negative pressure formation device for a battery according to claim 7, wherein A rubber pad is arranged between the insertion end surface of the cup body air guide part and the bottom surface of the first connecting groove.

9. The negative pressure formation device for a battery according to claim 7, wherein The upper end surface of the sealing nozzle is provided with a second connecting groove arranged in a concave mode, and the pre-tightening air guide part is inserted into the second connecting groove and is elastically interference-fitted with the second connecting groove.

10. The negative pressure formation device for a battery according to claim 4, wherein An air pipe joint is arranged at the end of the main body part away from the cup body air guide part, and the air pipe joint is used for being connected with an external negative pressure device.

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