Lithium battery

Abstract

The utility model relates to the technical field of lithium ion batteries, in particular to a lithium battery. The two cover plates are arranged at the two ends of the shell, an accommodating cavity is defined by the two cover plates and the shell, and each cover plate is provided with a pole located in the accommodating cavity; the pole core is arranged in the accommodating cavity, two opposite sides of the pole core are respectively provided with a pole lug, the two pole lugs are respectively connected with the two pole columns, the pole core is provided with a connecting surface and a bearing surface which are arranged between the two pole lugs and are opposite to each other, the connecting surface is in contact with the shell, the shell is provided with a liquid injection hole communicated with the accommodating cavity, and the bearing surface is opposite to the liquid injection hole. According to the lithium battery provided by the embodiment of the invention, the electrolyte injected from the liquid injection hole can be diffused to two sides instead of one-way diffusion, the infiltration distance is greatly shortened, the capillary action distance of the electrolyte is also shortened, the liquid injection efficiency can be improved, the infiltration time can be shortened, the production efficiency is improved, and the production cost is reduced. And the problem of poor edge voltage caused by the fact that the liquid injection hole is formed in the cover plate can be solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of lithium ion batteries, in particular to a lithium battery. BACKGROUND

[0002] Lithium ion batteries are widely used in electric vehicles, household appliances and other fields due to their unique characteristics of high specific energy, high working voltage, green safety and the like. Lithium ion batteries can be divided into soft package, cylindrical and square shell batteries according to the appearance. Among them, the square shell battery stands out from the crowd in the products due to its advantages of high energy density, high safety and high reliability. With the development of the new energy vehicle market, people have higher requirements for the vehicle mileage and battery life. Therefore, a kind of blade battery with large length-width ratio is developed, which can directly assemble the pack package, save the traditional module structure, improve the space utilization, and thus improve the energy density and structural strength of the battery pack.

[0003] The blade battery has a large length-width ratio characteristic, and the positive electrode cover plate and the negative electrode cover plate are usually arranged on the two sides of the length direction of the shell, and the liquid injection hole is arranged on one of the cover plates. During the trial production of the battery, the length direction of the battery is in a vertical position, and the electrolyte is injected into the shell through the liquid injection hole. However, since the liquid injection hole is arranged on the cover plate, when the electrolyte is injected, the electrolyte will flow to the position of the cover plate on the other side along the gap in the shell under the action of gravity, and then gradually infiltrate the electrode sheet in the electrode core from bottom to top by capillary action. Moreover, the length direction of the blade battery is long, and it takes a long time to completely infiltrate the electrode sheet, and the production efficiency is low. If the infiltration time is shortened, the electrode sheet may not be completely infiltrated, which affects the long-term performance of the battery. Moreover, when the liquid injection hole is arranged on the negative electrode cover plate or the positive electrode cover plate, the residual electrolyte at the liquid injection hole will cause poor edge voltage of the electrode core, which affects the product yield, and in severe cases, it may even cause corrosion and leakage of the electrode core. UTILITY MODEL CONTENT

[0004] In view of the above, it is necessary to provide a lithium battery to improve the infiltration efficiency of the electrode sheet in the electrode core and solve the problem of poor edge voltage caused by arranging the liquid injection hole on the cover plate.

[0005] The embodiment of the present application provides a lithium battery, which comprises a shell, two cover plates arranged at two ends of the shell and surrounding the shell to form a containing cavity, an electrode post arranged in the containing cavity on each cover plate, an electrode core arranged in the containing cavity, two electrode tabs arranged on opposite sides of the electrode core and connected with the two electrode posts respectively, a connecting surface and a receiving surface arranged between the two electrode tabs and opposite to each other, the connecting surface being in contact with the shell, the shell being provided with a liquid injection hole communicating with the containing cavity, and the receiving surface being arranged opposite to the liquid injection hole.

[0006] In some possible embodiments, the middle part of the receiving surface is arranged opposite to the liquid injection hole along the arrangement direction of the two cover plates.

[0007] In the embodiments of the present application, since the middle part of the receiving surface is arranged opposite to the liquid injection hole, the diffusion paths of the electrolyte injected from the liquid injection hole to both sides are consistent, so that the infiltration distance is greatly shortened, which helps to shorten the infiltration time, thereby improving the production efficiency.

[0008] In some possible embodiments, the lithium battery further comprises a buffer member arranged between the pole core and the liquid injection hole, and the buffer member is arranged opposite to the liquid injection hole.

[0009] In the embodiments of the present application, since the liquid injection hole has a relatively small opening diameter, the electrolyte needs to be pressurized during liquid injection to ensure that the electrolyte has enough power to diffuse to the inside of the pole core. By arranging the buffer member, the buffer member can alleviate the flow rate of the electrolyte injected from the liquid injection hole and the impact force on the receiving surface of the pole core, prevent the electrolyte injected from the liquid injection hole from directly shooting at the receiving surface of the pole core, and thus possibly causing the deformation of the pole piece in the pole core to cause poor pole piece interface and affect the long-term performance of the pole core.

[0010] In some possible embodiments, the buffer member comprises a liquid blocking area and a liquid guiding area, the liquid guiding area is arranged at the side of the liquid blocking area, and the liquid blocking area is arranged opposite to the liquid injection hole.

[0011] In the embodiments of the present application, by arranging the liquid blocking area opposite to the liquid injection hole, the liquid blocking area can alleviate the flow rate of the electrolyte injected from the liquid injection hole and the impact force on the receiving surface of the pole core, prevent the electrolyte injected from the liquid injection hole from directly shooting at the receiving surface of the pole core, and can guide the electrolyte injected from the liquid injection hole.

[0012] In some possible embodiments, the liquid guiding area comprises a plurality of liquid guiding openings, and the plurality of liquid guiding openings are uniformly and spacedly arranged.

[0013] In the embodiments of the present application, by arranging a plurality of liquid guiding openings, the electrolyte injected from the liquid injection hole can be more uniformly distributed on the pole core of the lithium battery, which can ensure that the electrolyte fully infiltrates the pole core and improve the charge and discharge efficiency and performance of the lithium battery; and the injection speed of the electrolyte can be accelerated, and the efficiency of the liquid injection process can be improved.

[0014] In some possible embodiments, the buffer member only comprises a liquid blocking area, and the liquid blocking area is arranged opposite to the liquid injection hole.

[0015] In the embodiments of the present application, by arranging the liquid blocking area opposite to the liquid injection hole, the liquid blocking area can alleviate the flow rate of the electrolyte injected from the liquid injection hole and the impact force on the receiving surface of the pole core, and prevent the electrolyte injected from the liquid injection hole from directly shooting at the receiving surface of the pole core.

[0016] In some possible embodiments, the length of the liquid blocking area is at least 2 times the diameter of the liquid injection hole along the arrangement direction of the two cover plates.

[0017] In the embodiments of the present application, the longer design of the liquid blocking area can effectively slow down the flow rate of the electrolyte injected from the liquid injection hole, avoiding the impact of the electrolyte flowing rapidly into the lithium battery on the pole core, thereby protecting the internal structure of the lithium battery. Moreover, the longer liquid blocking area helps to disperse the impact force of the electrolyte on the pole core receiving surface when the electrolyte is injected, reducing the damage caused by the direct impact of the electrolyte on the pole core, and protecting the internal structure of the lithium battery. In addition, the longer liquid blocking area can allow the electrolyte to have more time to disperse and evenly distribute before flowing into the lithium battery, which helps the electrolyte to more evenly soak the pole core, thereby improving the performance and life of the lithium battery. Furthermore, during the liquid injection process, the longer liquid blocking area helps to reduce the generation of bubbles, as bubbles can cause uneven distribution of the electrolyte and affect the performance of the lithium battery.

[0018] In some possible embodiments, the shell comprises a fixed plate, the fixed plate is arranged opposite to the receiving surface, the liquid injection hole is arranged on the fixed plate, and a flow guide channel is recessed on the side of the fixed plate close to the receiving surface, the flow guide channel extends along the arrangement direction of the two cover plates.

[0019] In the embodiments of the present application, the main function of the flow guide channel is to guide the electrolyte injected from the liquid injection hole to flow along a specific path, ensuring that the electrolyte can be evenly and effectively distributed to each part of the lithium battery, especially to each area of the pole core. During the liquid injection process, bubbles may be generated in the electrolyte. The flow guide channel can help the bubbles rise along the channel and be discharged from the lithium battery, reducing the impact of bubbles on the performance of the lithium battery. In addition, the flow guide channel can accelerate the injection process of the electrolyte, improve the injection efficiency, reduce the injection time, and also reduce the risk of electrolyte leakage during the injection process, thereby improving the sealing and safety of the lithium battery. Further, the design of the flow guide channel can also help to optimize the utilization of the internal space of the lithium battery, so that the components of the lithium battery are arranged more compactly, thereby improving the overall performance of the lithium battery.

[0020] In some possible embodiments, the length of each flow guide channel is less than half of the length of the fixed plate minus the diameter of the liquid injection hole along the arrangement direction of the two cover plates.

[0021] In the embodiments of the present application, it can be ensured that the electrolyte is evenly distributed during the injection process, avoiding too much or too little electrolyte in local areas, thereby improving the performance and life of the lithium battery.

[0022] In some possible embodiments, the liquid injection hole is a plurality of liquid injection holes, and the plurality of liquid injection holes are arranged on the fixed plate in an interval.

[0023] In the embodiments of this application, by providing multiple injection holes, electrolyte can be injected into the lithium battery simultaneously or separately. This accelerates the injection process and improves injection efficiency. Injecting electrolyte through multiple injection holes allows for a more uniform distribution of the electrolyte within the lithium battery, improving the electrolyte wetting effect. Multiple injection holes also ensure a more uniform injection volume, saving electrolyte, leaving no residual electrolyte on the lithium battery surface, and providing broad adaptability to different lithium battery models, thereby improving injection accuracy. During the injection process, multiple injection holes can balance the pressure distribution inside the lithium battery, reducing electrolyte flow obstruction or core damage caused by uneven pressure.

[0024] The lithium battery of this application embodiment, by having the electrolyte injection hole located on the casing and facing the receiving surface of the electrode core, allows the electrolyte injected through the injection hole to diffuse from one direction to both sides, significantly shortening the wetting distance and the capillary action distance of the electrolyte. This improves injection efficiency, helps shorten wetting time, and thus increases production efficiency. Furthermore, when the injection hole is located on the side of the casing, even if there is electrolyte residue in the injection hole, a blue film will be applied to the outside of the casing, preventing the possibility of electrolyte migrating to the cover plate side and communicating with the casing. This solves the problem of poor edge voltage caused by the injection hole being located on the cover plate. Attached Figure Description

[0025] Figure 1 This is a three-dimensional structural diagram of the lithium battery provided in the embodiments of this application.

[0026] Figure 2 yes Figure 1 The diagram shows the exploded structure of a lithium battery.

[0027] Figure 3 yes Figure 1 The diagram shows an exploded view of the lithium battery in another embodiment.

[0028] Figure 4 yes Figure 2 The diagram shows a cross-sectional structure of a lithium battery along the AA direction.

[0029] Explanation of main component symbols: Lithium battery 100, casing 10, opening 101, receiving cavity 11, liquid injection hole 12, fixing plate 13, flow channel 131, bottom plate 14, side plate 15, cover plate 20, electrode post 30, electrode core 40, electrode tab 41, connecting surface 42, receiving surface 43, buffer 50, liquid blocking area 51, liquid inlet area 52, liquid inlet port 521, Mylar membrane 60, sealing element 70, explosion-proof valve 80. Detailed Implementation

[0030] The embodiments of the present application are described below in detail, examples of which are shown in the drawings, wherein the same or similar notations represent the same or similar elements or elements having the same or similar functions throughout. The embodiments described below by referring to the drawings are exemplary only, for the purpose of explanation of the present application, and are not to be understood as a limitation of the present application.

[0031] In the description of the present application, it is to be understood that the terms indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings, and are only for the purpose of facilitating the description of the present application and simplifying the description, and are not to be understood as indicating or implying that the indicated device or element must have a particular orientation, be constructed and operated in a particular orientation, and therefore cannot be understood as a limitation of the present application. In addition, the terms "first", "second" are only for the purpose of description, and cannot be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined with "first", "second" can explicitly or implicitly include one or more of the features. In the description of the present application, it is to be noted that the meaning of "a plurality of" is two or more, unless otherwise explicitly specified and limited.

[0032] In the description of the present application, it is to be noted that, unless otherwise explicitly specified and limited, the term "connection" should be understood broadly, for example, it can be a fixed connection, or a detachable connection, or an integral connection; it can be a mechanical connection, or an electrical connection or can communicate with each other, it can be directly connected, or indirectly connected through an intermediate medium, it can be the internal communication of two elements or the interaction relationship between two elements. For those skilled in the art, the specific meaning of the above-mentioned term in the present application can be understood according to the specific circumstances. Some embodiments of the present application will be described in detail below with reference to the drawings.

[0033] Please refer to Figure 1 and Figure 2 The embodiments of the present application provide a lithium battery 100, which includes a shell 10, two cover plates 20, two pole columns 30 and pole cores 40. Wherein, the lithium battery 100 can be connected in series and / or in parallel to form battery packs with different sizes and capacities, which are used in electric equipment such as vehicles and ships.

[0034] The shell 10 is cuboid and has a large aspect ratio. Two cover plates 20 are arranged at the two ends of the shell 10 and surround the shell 10 to form a containing cavity 11. The containing cavity 11 is a cuboid cavity. Specifically, the shell 10 is provided with an opening 101 at each end, each cover plate 20 is arranged in the corresponding opening 101, and the outer peripheral wall of each cover plate 20 is sealingly connected to the edge of the corresponding opening 101 by welding. Each cover plate 20 is provided with a pole 30 located in the containing cavity 11. One of the poles 30 is a positive pole, and the other is a negative pole. Each pole 30 is fixedly connected to the cover plate 20 by compression of a sealing ring. The pole core 40 is cuboid and has a large aspect ratio. The pole core 40 is arranged in the containing cavity 11. The pole core 40 is provided with a positive pole lug 41 and a negative pole lug 41 on opposite sides. The positive pole lug 41 is connected to the positive pole by welding, and the negative pole lug 41 is connected to the negative pole by welding. The pole core 40 has a connecting surface 42 and a receiving surface 43 arranged between the two pole lugs 41. The connecting surface 42 and the receiving surface 43 are both flat surfaces. The connecting surface 42 is in contact with the shell 10. It can be understood that the connecting surface 42 is only in physical contact with the shell 10. The shell 10 is provided with a liquid injection hole 12 communicating with the containing cavity 11. The liquid injection hole 12 is a circular hole. It can be understood that in other embodiments, the liquid injection hole 12 can be a square hole, but is not limited thereto. The receiving surface 43 is arranged opposite the liquid injection hole 12. In this embodiment, the pole core 40 has two groups of opposite surfaces between the two pole lugs 41. One group has a larger area and is a wide surface. The other group has a smaller area and is a narrow surface. The connecting surface 42 and the receiving surface 43 are both narrow surfaces.

[0035] In some possible embodiments, the lithium battery 100 further comprises a sealing member 70 and an explosion-proof valve 80. The sealing member 70 is arranged in the liquid injection hole 12 after liquid injection. The explosion-proof valve 80 is arranged on one of the cover plates 20 and located on one side of the pole 30 on the cover plate 20.

[0036] The radius of the liquid injection hole 12 is 1 mm to 3 mm. The radius of the sealing member 70 is 1 mm to 3 mm. The radius of the sealing member 70 is smaller than the radius of the liquid injection hole 12. The difference between the radius of the liquid injection hole 12 and the radius of the sealing member 70 is 0.05 mm to 0.2 mm. The radius of the sealing member 70 is 0.2 mm to 0.6 mm. The material of the sealing member 70 can be an aluminum alloy. By making the radius of the sealing member 70 smaller than the radius of the liquid injection hole 12, good contact and sealing effect between the sealing member 70 and the liquid injection hole 12 can be ensured, and leakage of electrolyte after liquid injection can be prevented.

[0037] At least one of the two cover plates 20 is a neutral cover plate 20, for example, one can be a neutral cover plate 20, and the other can be a charged cover plate 20; or both can be neutral cover plates 20. When one is a neutral cover plate 20 and the other is a charged cover plate 20, the neutral cover plate 20 serves as a negative cover plate 20, and the charged cover plate 20 serves as a positive cover plate 20.

[0038] In some possible embodiments, along the arrangement direction of the two cover plates 20, the middle part of the receiving surface 43 is arranged opposite the injection hole 12. Wherein the pole core 40 is arranged at the middle part of the accommodation cavity 11, since the middle part of the receiving surface 43 is arranged opposite the injection hole 12, the path of the electrolyte injected from the injection hole 12 to diffuse to both sides is consistent, which greatly shortens the wetting distance, helps to shorten the wetting time, and thus improves the production efficiency.

[0039] In some possible embodiments, the lithium battery 100 further comprises a buffer 50, which is arranged between the pole core 40 and the injection hole 12, and the buffer 50 is arranged opposite the injection hole 12. Since the injection hole 12 has a relatively small opening diameter, it needs to be pressurized during injection to ensure that the electrolyte has enough power to diffuse to the inside of the pole core 40. By arranging the buffer 50, the buffer 50 can alleviate the flow rate of the electrolyte injected from the injection hole 12 and the impact force on the receiving surface 43 of the pole core 40, prevent the electrolyte injected from the injection hole 12 from directly hitting the receiving surface 43 of the pole core 40, and thus possibly causing the deformation of the pole piece in the pole core 40 to cause poor pole piece interface and affect the long-term performance of the pole core 40.

[0040] In some possible embodiments, the buffer 50 comprises a liquid blocking area 51 and two liquid guiding areas 52, the two liquid guiding areas 52 are arranged on opposite sides of the liquid blocking area 51, and the liquid blocking area 51 is arranged opposite the injection hole 12. Specifically, the buffer 50 is connected to the receiving surface 43 of the pole core 40, and the material of the buffer 50 can be PVC, PC, PPS, PPO, ABS, etc. high molecular material with good forming and mechanical properties, the liquid blocking area 51 is a solid structure, and the liquid guiding area 52 is a hollow structure. The buffer 50 has a relatively light mass and has a small impact on the energy density of the pole core 40. By arranging the liquid blocking area 51 opposite the injection hole 12, the liquid blocking area 51 can alleviate the flow rate of the electrolyte injected from the injection hole 12 and the impact force on the receiving surface 43 of the pole core 40, prevent the electrolyte injected from the injection hole 12 from directly hitting the receiving surface 43 of the pole core 40, and can guide the electrolyte injected from the injection hole 12 through the two liquid guiding areas 52.

[0041] Wherein, along the spacing direction of the two cover plates 20, the length of the buffer 50 is consistent with the length of the pole core 40, so that the liquid guiding area 52 can guide the electrolyte to the receiving surface 43 of the pole core 40.

[0042] The thickness of the buffer 50 is in the range of 0.2mm-0.5mm. In this way, sufficient structural stability can be provided while maintaining a certain flexibility to adapt to the pressure changes and mechanical vibrations inside the lithium battery 100.

[0043] The area of the liquid blocking area 51 of the buffer 50 is 1.1-3 times the cross-sectional area of the liquid injection hole 12. In this way, the flow rate of the electrolyte injected from the liquid injection hole 12 can be effectively slowed down, and the impact force of the electrolyte on the receiving surface 43 of the pole core 40 can be reduced, which helps to protect the sensitive components inside the lithium battery 100 and avoid damage to the pole core 40 due to excessive impact force. A larger liquid blocking area 51 area helps to evenly distribute the electrolyte inside the lithium battery 100, improves the liquid injection efficiency, ensures that the electrolyte can fully soak the pole core 40, and thus improves the performance and life of the lithium battery 100.

[0044] In some possible embodiments, each liquid guiding area 52 includes a plurality of liquid guiding openings 521, and the plurality of liquid guiding openings 521 are uniformly spaced. Specifically, the liquid guiding openings 521 of each liquid guiding area 52 are eight and arranged in two rows. By arranging a plurality of liquid guiding openings 521, the electrolyte injected from the liquid injection hole 12 can be more evenly distributed on the pole core 40 of the lithium battery 100, which can ensure that the electrolyte fully soaks the pole core 40 and improve the charge and discharge efficiency and performance of the lithium battery 100; and can speed up the injection speed of the electrolyte and improve the efficiency of the liquid injection process.

[0045] Please refer to Figure 3 In some possible embodiments, the buffer 50 only includes a liquid blocking area 51, and the liquid blocking area 51 is arranged opposite to the liquid injection hole 12. Specifically, the buffer 50 is bonded to the receiving surface 43 of the pole core 40, and the buffer 50 is an adhesive tape, which can be one layer or multiple layers. By arranging the liquid blocking area 51 opposite to the liquid injection hole 12, the liquid blocking area 51 can alleviate the flow rate of the electrolyte injected from the liquid injection hole 12 and the impact force on the receiving surface 43 of the pole core 40, and prevent the electrolyte injected from the liquid injection hole 12 from being directly shot at the receiving surface 43 of the pole core 40.

[0046] In some possible embodiments, the length of the liquid blocking area 51 along the arrangement direction of the two cover plates 20 is at least 2 times the diameter of the liquid injection hole 12. The longer design of the liquid blocking area 51 can effectively slow down the flow rate of the electrolyte injected from the liquid injection hole 12, avoiding the impact of the electrolyte flowing rapidly into the interior of the lithium battery 100 on the pole core 40, thereby protecting the internal structure of the lithium battery 100. Moreover, the longer liquid blocking area 51 helps to disperse the impact force of the electrolyte on the receiving surface 43 of the pole core 40 when the electrolyte is injected, reducing the damage caused by the direct impact of the electrolyte on the pole core 40, and protecting the internal structure of the lithium battery 100. In addition, the longer liquid blocking area 51 can allow the electrolyte more time to disperse and evenly distribute before flowing into the interior of the lithium battery 100, helping the electrolyte to more evenly soak the pole core 40, and improving the performance and life of the lithium battery 100. Furthermore, the longer liquid blocking area 51 helps to reduce the generation of air bubbles during the liquid injection process, as air bubbles can cause uneven distribution of the electrolyte and affect the performance of the lithium battery 100.

[0047] Please also refer to Figure 2 and Figure 4 In some possible embodiments, the shell 10 includes a fixed plate 13, a bottom plate 14 opposite to the fixed plate 13, and two side plates 15. The fixed plate 13, the bottom plate 14, and the two side plates 15 are an integral structure, the two side plates 15 are oppositely arranged and respectively connected to the fixed plate 13 and the bottom plate 14, the connecting surface 42 of the pole core 40 is in contact with the bottom plate 14, and it can be understood that the connecting surface 42 is only in physical contact with the bottom plate 14. The two tabs 41 are arranged close to the bottom plate 14, the fixed plate 13 is arranged opposite to the receiving surface 43, the liquid injection hole 12 is arranged on the fixed plate 13, and a plurality of flow guide channels 131 are arranged on the side of the fixed plate 13 close to the receiving surface 43. The plurality of flow guide channels 131 are arranged on opposite sides of the liquid injection hole 12, and the flow guide channels 131 extend along the arrangement direction of the two cover plates 20. The main function of the flow guide channels 131 is to guide the electrolyte injected from the liquid injection hole 12 to flow along a specific path, ensuring that the electrolyte can be evenly and effectively distributed to each part of the interior of the lithium battery 100, especially to each area of the pole core 40. In addition, the flow guide channels 131 can accelerate the injection process of the electrolyte, improve the injection efficiency, reduce the injection time, and also reduce the risk of electrolyte leakage during the injection process, thereby improving the sealing performance and safety of the lithium battery 100. Further, the design of the flow guide channels 131 can also help to optimize the utilization of the internal space of the lithium battery 100, so that the components of the lithium battery 100 are arranged more compactly, thereby improving the overall performance of the lithium battery 100.

[0048] In the above embodiments, the thickness of the fixed plate 13 at the flow guide channels 131 is 0.4mm-0.7mm. In this way, the fixed plate 13 can have sufficient mechanical strength and structural stability to withstand various mechanical stresses during the assembly and use of the lithium battery 100.

[0049] The thickness of the corresponding fixed plate 13 at the flow guide channel 131 is 0.3mm-0.5mm. In this way, the amount of material can be reduced while maintaining the functionality of the flow guide channel 131, ensuring that the electrolyte can flow smoothly into the lithium battery 100.

[0050] The length of each flow guide channel 131 along the setting direction of the two cover plates 20 is less than half the length of the fixed plate 13 minus the diameter of the liquid injection hole 12. In this way, the electrolyte can be evenly distributed during injection to avoid excessive or insufficient electrolyte in local areas, thereby improving the performance and life of the lithium battery 100.

[0051] In some possible embodiments, the outer periphery of the pole core 40 is covered with a Mylar film 60, which is arranged opposite the liquid injection hole 12. By arranging the Mylar film 60, the pole core 40 can be protected from the external environment, including preventing the pole core 40 from being damp, contaminated, mechanically damaged, etc., thereby prolonging the service life of the pole core. And it can play a role in alleviating the impact of electrolyte on the pole core 40, avoiding deformation of the pole piece in the pole core 40.

[0052] In some possible embodiments, the liquid injection hole 12 is a plurality of liquid injection holes 12, which are arranged on the fixed plate 13. By arranging multiple liquid injection holes 12, multiple liquid injection holes 12 can simultaneously or separately inject electrolyte into the lithium battery 100, which can speed up the injection process and improve injection efficiency. By injecting electrolyte through multiple liquid injection holes 12, the distribution of electrolyte in the lithium battery 100 can be more uniform, improving electrolyte wettability. Multiple liquid injection holes 12 can make the injection amount more uniform, save electrolyte, and there is no residual electrolyte on the surface of the lithium battery 100, and the adaptability to different models of lithium batteries 100 is wide, thereby improving the injection precision. During the injection process, multiple liquid injection holes 12 can balance the pressure distribution inside the lithium battery 100, reducing the electrolyte flow or damage to the pole core 40 caused by uneven pressure.

[0053] During injection, the liquid injection hole 12 faces upwards, and electrolyte is injected into the liquid injection hole 12. The injection flow rate and impact force of the electrolyte are buffered by the liquid blocking area 51 of the buffer 50, while the electrolyte spreads to the upper side of the tab 41 away from the liquid injection hole 12 under the guidance of the flow guide channel 131, and wets the pole piece in the pole core 40 under the action of capillary force. After injection is completed and exhaust, the sealing member 70 seals the liquid injection hole 12.

[0054] The lithium battery 100 of the embodiment of the present application can make the electrolyte injected from the injection hole 12 diffuse to both sides from single direction, greatly shorten the infiltration distance, shorten the electrolyte capillary action distance, improve the injection efficiency, help to shorten the infiltration time, and thus improve the production efficiency. Moreover, when the injection hole 12 is arranged on the side of the shell 10, even if the injection hole 10 has electrolyte residue, the shell 10 is still covered with a blue film outside, which can prevent the electrolyte from migrating to the side of the cover plate 20 and communicating with the shell, and can solve the problem of side voltage caused by arranging the injection hole 12 on the cover plate.

[0055] It is apparent for those skilled in the art that the present application is not limited to the details of the above-described exemplary embodiments, but can be implemented in other concrete forms without departing from the spirit or essential characteristics of the present application. Therefore, the embodiments should be considered in all aspects as illustrative and not restrictive, and the scope of the present application is defined by the appended claims rather than the above description, and it is intended to include all changes falling within the meaning and range of equivalents of the claims.

[0056] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application but not limit the present application, and although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or replaced equivalently without departing from the spirit and scope of the technical solutions of the present application.

Claims

1. A lithium battery, characterized by, The lithium battery comprises a shell, two cover plates arranged at two ends of the shell and surrounding the shell to form a containing cavity, an electrode post arranged on each cover plate and located in the containing cavity, an electrode core arranged in the containing cavity, two electrode ears arranged on opposite sides of the electrode core and connected with the electrode posts, a connecting surface and a receiving surface arranged between the two electrode ears, the connecting surface being in contact with the shell, the shell being provided with a liquid injection hole communicating with the containing cavity, and the receiving surface being arranged opposite to the liquid injection hole. The middle part of the receiving surface is arranged opposite to the liquid injection hole along the arrangement direction of the two cover plates. The lithium battery further comprises a buffer member arranged between the electrode core and the liquid injection hole and arranged opposite to the liquid injection hole. The buffer member comprises a liquid blocking area and a liquid guiding area, the liquid guiding area being arranged on the side of the liquid blocking area and arranged opposite to the liquid injection hole.

2. The lithium battery of claim 1, wherein, The liquid guiding area comprises a plurality of liquid guiding holes, and the liquid guiding holes are uniformly and spacedly arranged.

3. The lithium battery of claim 1, wherein, The buffer member only comprises a liquid blocking area, and the liquid blocking area is arranged opposite to the liquid injection hole.

4. The lithium battery of claim 3, wherein the lithium metal anode is a lithium foil anode. The length of the liquid blocking area is at least 2 times the diameter of the liquid injection hole along the arrangement direction of the two cover plates.

5. The lithium battery of claim 4, wherein the lithium metal anode is a lithium foil anode. The shell comprises a fixed plate arranged opposite to the receiving surface, the liquid injection hole is arranged on the fixed plate, and the fixed plate is recessed with a flow guide channel on the side close to the receiving surface, and the flow guide channel extends along the arrangement direction of the two cover plates.

6. The lithium battery of claim 3, wherein the lithium metal anode is a lithium foil anode. The length of each flow guide channel is less than half the length of the fixed plate minus the diameter of the liquid injection hole along the arrangement direction of the two cover plates.

7. The lithium battery of claim 6, wherein the lithium metal anode is a lithium foil anode. The liquid injection hole is a plurality of liquid injection holes, and the liquid injection holes are spacedly arranged on the fixed plate.

8. The lithium battery of claim 1, wherein, ​ 9. The lithium battery of claim 8, wherein the lithium metal anode is a lithium foil anode. ​ 10. The lithium battery of claim 8, wherein the lithium metal anode is coated with a layer of lithium phosphorus oxynitride. ​

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