WO2023131031A1

WO2023131031A1 - Battery cell, battery, and electric device

Info

Publication number: WO2023131031A1
Application number: PCT/CN2022/142899
Authority: WO
Inventors: 连登伟
Original assignee: 宁德时代新能源科技股份有限公司
Priority date: 2022-01-07
Filing date: 2022-12-28
Publication date: 2023-07-13
Also published as: CN216903150U

Abstract

The present application relates to the technical field of new energy, in particular to a battery cell, a battery, and an electric device. The battery cell comprises: a housing provided with an opening; an end cover, which covers the opening, wherein a first recess is formed in the side of the end cover away from the housing, the thickness of a bottom wall of the first recess is smaller than that of the surrounding end cover, an electrolyte injection structure is arranged on the bottom wall of the first recess, and is formed by piercing the bottom wall towards the inside of the housing from the surface of the bottom wall of the first recess away from the housing, and the first recess and the electrolyte injection structure form an electrolyte injection path; and a sealing portion for sealing the electrolyte injection path. According to the present application, by means of the mode, an electrolyte can be supplied to the battery cell, thereby improving the performance of the battery cell and prolonging the service life of the battery cell.

Description

A battery cell, battery and electrical device

cross reference

This application refers to the Chinese patent application No. 202220038570.X entitled "A Battery Cell, Battery, and Electric Device" filed on January 7, 2022, which is incorporated by reference into this application in its entirety.

technical field

The present application relates to the field of new energy technology, in particular to a battery cell, a battery and an electrical device.

Background technique

Energy conservation and emission reduction is the key to the sustainable development of the automobile industry, and electric vehicles have become an important part of the sustainable development of the automobile industry due to their advantages in energy conservation and environmental protection. For electric vehicles, battery technology is an important factor in its development.

With the rapid development of the new energy field, the application fields of batteries are becoming more and more extensive, so higher requirements are put forward for the performance and life of batteries. The applicant found in the research that the battery forms a sealed space through the cover of the end cover and the casing, and the electrolyte is provided in the sealed space to provide a charging and discharging environment. For lithium batteries, as the number of reactions between lithium ions and electrolytes increases, The electrolyte is consumed and cannot be replenished, resulting in a decrease in the performance of the battery and a serious decline in life.

Contents of the invention

In view of the above problems, the present application provides a battery cell, a battery and an electrical device, so as to be able to replenish electrolyte to the battery cell, improve the performance of the battery cell, and prolong the service life of the battery cell.

According to one aspect of the present application, there is provided a battery cell, comprising: a housing with an opening; an end cover disposed on the opening, a first recess is formed on the side of the end cover away from the housing, and the first recess is The thickness of the bottom wall is smaller than the thickness of the surrounding end cover; a liquid injection structure is arranged on the bottom wall of the first recessed part, and the liquid injection structure is from the surface of the bottom wall of the first recessed part far away from the shell toward the inside of the shell It is formed by piercing the bottom wall; the first recessed part and the liquid injection structure form a liquid injection path; the sealing part seals the liquid injection path.

Due to the thickness of the end cap, it is difficult to pierce. In order to reduce the difficulty of opening a liquid injection path on the end cap, a first recess is provided on the surface of the end cap away from the housing, so that the bottom wall of the first recess The thickness of the bottom wall is smaller than the thickness of the surrounding end cover. When piercing the bottom wall from the surface of the bottom wall of the first recessed portion away from the shell toward the inside of the shell, the bottom wall structure bends inward to form a liquid injection structure, so it will not be cut. The components of the end cover can be removed or worn off, so as to effectively prevent impurities from falling into the shell during the opening of the liquid injection path and affect the internal electrolyte environment. The sealing of the liquid injection path can be achieved by setting the sealing part to ensure The interior of the battery cell can still be well sealed after liquid.

In some embodiments, the section of the liquid injection structure is arranged in an inverted "eight" shape on a plane perpendicular to the end cap. By setting the cross-section of the liquid injection structure in an inverted "eight" shape on a plane perpendicular to the end cap, so that the first recess and the liquid injection structure together form a funnel-shaped liquid injection path, the liquid injection structure can control the liquid injection path The electrolyte injected into the battery acts as a guide.

In some embodiments, the sealing part is disposed in the first concave part and is sealingly connected with the first concave part. By sealing the sealing part in the first concave part, the sealing inside the battery cell is realized after the electrolyte is injected, and the stability of the subsequent operation of the battery cell is ensured.

In some embodiments, the sealing part is disposed in the liquid injection structure and is in sealing connection with the liquid injection structure. By arranging the sealing part in the liquid injection structure, the sealing inside the battery cell is realized after the electrolyte is injected, so as to ensure the stability of the subsequent work of the battery cell.

In some embodiments, a second recess is formed on the side of the end cover away from the housing, the first recess is formed on the bottom wall of the second recess, and the sealing portion is disposed in the second recess. By forming a second recessed portion on the side of the end cover away from the housing, the first recessed portion is formed on the bottom wall of the second recessed portion, and the sealing portion is arranged in the second recessed portion, so that the sealing portion and the second recessed portion The sealing contact is formed between the side wall and the bottom wall. Compared with the way that the sealing part is arranged in the first concave part or the liquid injection structure, the area of the sealing contact is increased, so that the sealing performance can be further improved.

In some embodiments, an edge of the sealing portion is welded to the second recess. By welding the edge of the sealing part to the second concave part, the sealing of the sealing part to the liquid injection path is realized, and the sealing performance of the internal space of the battery cell is ensured. At the same time, since the first depression is formed on the bottom wall of the second depression, when the structure at the edge of the sealing part melts and flows into the gap between the second depression, the molten structure that flows in is absorbed at the bottom wall of the second depression. The limit stop can effectively prevent the molten structure at the edge of the sealing part from flowing into the battery cell and affecting the electrolyte.

In some embodiments, a groove is provided at an end of the sealing portion away from the housing, and the groove is used for releasing stress generated by welding. During welding, the parts to be welded are first melted and then solidified and welded. The molten structure is limited by the unmelted structure during the solidification process and will generate welding stress. By setting a groove at the end of the sealing part away from the shell, the edge of the sealing part During welding, a part of the molten structure flows and fills between the sealing portion and the side wall of the second concave portion, and the other part flows in the groove, so that the molten structure at the edge of the sealing portion will not be restricted by other structures during the solidification process, thereby Ensure that the welding stress can be released, and enhance the structural stability of the sealing part after welding.

In some embodiments, the sealing part is sealingly connected with the second recessed part through a sealant. After the sealing part is placed in the second recessed part, a sealant can be injected into the gap between the edge of the sealing part and the side wall of the second recessed part, and after the sealant is filled in the gap and dried and cured, the sealing part is sealed and fixed on the In the second recessed portion, the sealing performance inside the battery cell is ensured.

According to another aspect of the present application, a battery is also provided, including the battery cell in any one of the above-mentioned embodiments.

According to another aspect of the present application, there is also provided an electric device, including the above-mentioned battery, and the battery is used to provide power.

The above description is only an overview of the technical solution of the present application. In order to better understand the technical means of the present application, it can be implemented according to the contents of the description, and in order to make the above and other purposes, features and advantages of the present application more obvious and understandable , the following specifically cites the specific implementation manner of the present application.

Description of drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present application, the following will briefly introduce the accompanying drawings that need to be used in the embodiments of the present application. Obviously, the accompanying drawings described below are only some embodiments of the present application. Those of ordinary skill in the art can also obtain other drawings based on the accompanying drawings on the premise of not paying creative efforts. Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiment. The drawings are only for the purpose of illustrating the preferred embodiments and are not to be considered as limiting the application. Also throughout the drawings, the same reference numerals are used to designate the same parts. In the attached picture:

FIG. 1 is a schematic structural diagram of a vehicle provided in an embodiment of the present application;

Fig. 2 is a schematic diagram of the explosive structure of the battery provided in the embodiment of the present application;

Fig. 3 is a schematic diagram of an exploded structure of a battery cell provided in an embodiment of the present application;

FIG. 4 is a schematic cross-sectional structural view of a battery cell provided in an embodiment of the present application;

FIG. 5 is a schematic cross-sectional structural view of an end cap in a battery cell provided by another embodiment of the present application;

FIG. 6 is a schematic cross-sectional structural view of an end cap in a battery cell provided by another embodiment of the present application;

Fig. 7 is a schematic cross-sectional structural view of a battery cell provided by another embodiment of the present application before welding the sealing part on the end cover and the second concave part;

FIG. 8 is a structural schematic view of the sealing part of the end cover in FIG. 7 after welding with the second recessed part.

The reference numerals in the specific embodiment are as follows:

vehicle 1000;

battery 100, controller 200, motor 300;

Box 10, first part 11, second part 12;

battery cell 20, end cap 21, electrode terminal 21a, first recessed part 211, liquid injection structure 212, second recessed part 213, case 22, opening 221, electrode assembly 23, tab 23a, sealing part 24, concave Slot 241.

Detailed ways

Embodiments of the technical solutions of the present application will be described in detail with reference to the accompanying drawings. The following examples are only used to illustrate the technical solution of the present application more clearly, and therefore are only examples, rather than limiting the protection scope of the present application.

Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the technical field of the application; the terms used herein are only for the purpose of describing specific embodiments, and are not intended to To limit this application; the terms "comprising" and "having" and any variations thereof in the specification and claims of this application and the description of the above drawings are intended to cover a non-exclusive inclusion.

In the description of the embodiments of the present application, technical terms such as "first" and "second" are only used to distinguish different objects, and should not be understood as indicating or implying relative importance or implicitly indicating the number, specificity, or specificity of the indicated technical features. Sequence or primary-secondary relationship. In the description of the embodiments of the present application, "plurality" means two or more, unless otherwise specifically defined.

Reference herein to an "embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the present application. The occurrences of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is understood explicitly and implicitly by those skilled in the art that the embodiments described herein can be combined with other embodiments.

In the description of the embodiment of the present application, the term "and/or" is only an association relationship describing associated objects, which means that there may be three relationships, such as A and/or B, which may mean: there is A, and there are A and B, there are three situations of B. In addition, the character "/" in this article generally indicates that the contextual objects are an "or" relationship.

In the description of the embodiments of the present application, the term "multiple" refers to more than two (including two), similarly, "multiple groups" refers to more than two groups (including two), and "multiple pieces" refers to More than two pieces (including two pieces).

In the description of the embodiments of the present application, the technical terms "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical" "Horizontal", "Top", "Bottom", "Inner", "Outer", "Clockwise", "Counterclockwise", "Axial", "Radial", "Circumferential", etc. indicate the orientation or positional relationship based on the drawings Orientation or positional relationship is only for the convenience of describing the embodiment of the present application and simplifying the description, and does not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as an implementation of the present application. Example limitations.

In the description of the embodiments of this application, unless otherwise clearly specified and limited, technical terms such as "installation", "connection", "connection" and "fixation" should be interpreted in a broad sense, for example, it can be a fixed connection or a fixed connection. Disassembled connection, or integration; it can also be a mechanical connection, or an electrical connection; it can be a direct connection, or an indirect connection through an intermediary, and it can be the internal communication of two components or the interaction relationship between two components. Those of ordinary skill in the art can understand the specific meanings of the above terms in the embodiments of the present application according to specific situations.

At present, judging from the development of the market situation, the application of batteries is becoming more and more extensive. Batteries are not only used in energy storage power systems such as hydropower, firepower, wind power and solar power plants, but also widely used in electric vehicles such as electric bicycles, electric motorcycles, electric vehicles, as well as military equipment and aerospace and other fields. With the continuous expansion of battery application fields, its market demand is also constantly expanding.

For lithium batteries, in order to ensure a good charging and discharging environment inside the battery cell, it is necessary to ensure good sealing when the shell and the end cover are assembled, so that a sealed space is formed between the shell and the end cover and the The electrode assembly and electrolyte are arranged in the sealed space to realize the charging and discharging of the battery cells. During the charging and discharging process of the battery cell, the lithium ions on the electrode assembly react with the electrolyte, and as the number of reactions increases, the electrolyte is consumed, and the performance of the battery cell decreases accordingly, and the life expectancy correspondingly occurs attenuation.

Due to the need to ensure the sealing of the battery cells, after the battery cells are assembled, even if the electrolyte is consumed, subsequent replenishment cannot be performed, resulting in a low life of the battery cells, and as the battery cells are used for a long time The performance of the battery cell also decreases.

Based on the above problems, the present application proposes a battery cell. By forming a first depression on the side of the end cover away from the casing, the thickness of the bottom wall of the first depression is smaller than the thickness of the surrounding end cover, so that the first The surface of the bottom wall of the recessed portion away from the casing is pierced toward the inside of the casing to form the bottom wall to form a liquid injection structure, and the liquid injection structure formed by piercing will not produce metal shavings, thereby preventing impurities from falling into the battery cell. The first recessed part and the liquid injection structure together form a liquid injection path to realize the injection and replenishment of the electrolyte solution inside the battery cell. The liquid injection path is sealed by the sealing part to ensure that after liquid replenishment, the inside of the battery cell still has a good sealing environment, providing a reliable environment for the charging and discharging of the battery cell. The solution proposed in this application is not only applicable to the liquid injection process of battery cells that are produced and assembled for the first time. A recessed part and a liquid injection structure realize secondary replenishment of the battery cells to improve the performance of the battery cells and prolong the service life of the battery cells.

The batteries disclosed in the embodiments of the present application can be used, but not limited to, in electric devices such as vehicles, ships or aircrafts.

The embodiment of the present application provides an electric device using a battery as a power source. The electric device can be, but not limited to, a mobile phone, a tablet, a notebook computer, an electric toy, an electric tool, a battery car, an electric car, a ship, a spacecraft, etc. Among them, electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric boat toys, electric airplane toys, etc., and spacecraft may include airplanes, rockets, space shuttles, spaceships, etc.

In the following embodiments, for the convenience of description, a vehicle 1000 as an electric device according to an embodiment of the present application is taken as an example for description.

Please refer to FIG. 1 , which is a schematic structural diagram of a vehicle 1000 provided by some embodiments of the present application. The vehicle 1000 can be a fuel vehicle, a gas vehicle or a new energy vehicle, and the new energy vehicle can be a pure electric vehicle, a hybrid vehicle or an extended-range vehicle. The interior of the vehicle 1000 is provided with a battery 100 , and the battery 100 may be provided at the bottom, head or tail of the vehicle 1000 . The battery 100 can be used for power supply of the vehicle 1000 , for example, the battery 100 can be used as an operating power source of the vehicle 1000 . The vehicle 1000 may further include a controller 200 and a motor 300 , the controller 200 is used to control the battery 100 to supply power to the motor 300 , for example, for starting, navigating and running the vehicle 1000 .

In some embodiments of the present application, the battery 100 can not only be used as an operating power source for the vehicle 1000 , but can also be used as a driving power source for the vehicle 1000 , replacing or partially replacing fuel oil or natural gas to provide driving power for the vehicle 1000 .

Please refer to FIG. 2 . FIG. 2 is a schematic diagram of an exploded structure of a battery 100 provided by some embodiments of the present application. The battery 100 includes a case 10 and battery cells 20 housed in the case 10 . Wherein, the box body 10 is used to provide accommodating space for the battery cells 20 , and the box body 10 may adopt various structures. In some embodiments, the box body 10 may include a first part 11 and a second part 12, the first part 11 and the second part 12 cover each other, the first part 11 and the second part 12 jointly define a of accommodation space. The second part 12 can be a hollow structure with one end open, the first part 11 can be a plate-shaped structure, and the first part 11 covers the opening side of the second part 12, so that the first part 11 and the second part 12 jointly define an accommodation space ; The first part 11 and the second part 12 can also be hollow structures with one side opening, and the opening side of the first part 11 is covered by the opening side of the second part 12 . Of course, the box body 10 formed by the first part 11 and the second part 12 can be in various shapes, such as a cylinder, a cuboid and the like.

In the battery 100 , there may be multiple battery cells 20 , and the multiple battery cells 20 may be connected in series, in parallel or in parallel. The mixed connection means that the multiple battery cells 20 are connected in series and in parallel. A plurality of battery cells 20 can be directly connected in series, in parallel or mixed together, and then the whole composed of a plurality of battery cells 20 is housed in the box 10; of course, the battery 100 can also be a plurality of battery cells 20 The battery modules are firstly connected in series or parallel or in combination, and then multiple battery modules are connected in series or in parallel or in combination to form a whole, which is accommodated in the case 10 . The battery 100 may also include other structures, for example, the battery 100 may also include a bus component for realizing electrical connection between multiple battery cells 20 .

Wherein, each battery cell 20 may be a secondary battery or a primary battery; it may also be a lithium-sulfur battery, a sodium-ion battery or a magnesium-ion battery, but not limited thereto. The battery cell 20 may be in the form of a cylinder, a flat body, a cuboid or other shapes.

Please refer to FIG. 3 . FIG. 3 is a schematic diagram of an exploded structure of a battery cell 20 in a battery 100 provided in some embodiments of the present application. The battery cell 20 refers to the smallest unit constituting a battery. As shown in FIG. 3 , the battery cell 20 includes an end cover 21 , a casing 22 , an electrode assembly 23 and other functional components.

The end cap 21 refers to a component that covers the opening of the casing 22 to isolate the internal environment of the battery cell 20 from the external environment. Without limitation, the shape of the end cap 21 can be adapted to the shape of the housing 22 to fit the housing 22 . In some embodiments, the end cap 21 can be made of a material (such as aluminum alloy) with a certain hardness and strength, so that the end cap 21 is not easy to deform when being squeezed and collided, so that the battery cell 20 can have more With high structural strength, safety performance can also be improved. Functional components such as electrode terminals 21 a may be provided on the end cap 21 . The electrode terminal 21 a can be used to be electrically connected with the electrode assembly 23 for outputting or inputting electric energy of the battery cell 20 . In some embodiments, the end cover 21 may also be provided with a pressure relief mechanism for releasing the internal pressure when the internal pressure or temperature of the battery cell 20 reaches a threshold value. The material of the end cap 21 can also be various, for example, copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not particularly limited in this embodiment of the present application. In some embodiments, an insulator can be provided inside the end cover 21 , and the insulator can be used to isolate the electrical connection components in the housing 22 from the end cover 21 to reduce the risk of short circuit. For example, the insulation may be plastic, rubber, or the like.

The casing 22 is a component used to cooperate with the end cap 21 to form the internal environment of the battery cell 20 , wherein the formed internal environment can be used to accommodate the electrode assembly 23 , electrolyte and other components. The housing 22 and the end cover 21 can be independent components, and an opening can be provided on the housing 22 , and the internal environment of the battery cell 20 can be formed by making the end cover 21 cover the opening at the opening. Without limitation, the end cover 21 and the housing 22 may also be integrated. The housing 22 can be in various shapes and sizes, such as cuboid, cylinder, hexagonal prism and so on. Specifically, the shape of the casing 22 can be determined according to the specific shape and size of the electrode assembly 23 . The housing 22 can be made of various materials, such as copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc., which is not particularly limited in this embodiment of the present application.

The electrode assembly 23 is a part where the electrochemical reaction occurs in the battery cell 20 . One or more electrode assemblies 23 may be contained within the case 22 . The electrode assembly 23 is mainly formed by winding or stacking positive electrode sheets and negative electrode sheets, and a separator is usually provided between the positive electrode sheets and the negative electrode sheets. The part of the positive electrode sheet and the negative electrode sheet with the active material constitutes the main body of the electrode assembly, and the parts of the positive electrode sheet and the negative electrode sheet without the active material respectively constitute the tab 23a. The positive pole tab and the negative pole tab can be located at one end of the main body together or at two ends of the main body respectively. During the charging and discharging process of the battery, the positive electrode active material and the negative electrode active material react with the electrolyte, and the tabs 23a are connected to the electrode terminals to form a current loop.

According to an aspect of an embodiment of the present application, a battery cell is provided, please refer to FIG. 4 for details, which shows a cross-sectional structure of a battery cell 20 provided by an embodiment of the present application. The battery cell 20 includes an end cap 21 , a case 22 and a sealing portion 24 . The housing 22 has an opening 221, and the end cover 21 is covered at the opening 221. A first recess 211 is formed on the side of the end cover 21 away from the housing 22. The thickness of the bottom wall of the first recess 211 is smaller than that of all the surrounding end covers 21. thickness of. A liquid injection structure 212 is provided on the bottom wall of the first recessed portion 211, and the liquid injection structure 212 pierces the bottom wall from the surface of the bottom wall of the first recessed portion 211 that is far away from the housing 22 toward the interior of the housing 22. Formed, the first recessed portion 211 and the liquid injection structure 212 form a liquid injection path. The sealing portion 24 seals the liquid injection path.

As shown in FIG. 4 , an end cap 21 is provided at the opening 221 of the housing 22 of the battery cell 20 . In order to replenish the battery cell 20 , a liquid injection path needs to be formed on the end cap 21 . The liquid injection path is set The location of the battery can be selected according to the specific structure of the battery cell. Usually, the end cover 21 is provided with structures such as explosion-proof valves. In order to avoid conflicts between the liquid injection path and structures such as explosion-proof valves, the liquid injection path can be set at a position away from structures such as explosion-proof valves. In some embodiments, it can be The liquid injection path is arranged on one side edge of the end cap, which is not limited in this embodiment of the present application.

In order to form the liquid injection path, for the secondary recovered battery cells 20, it is necessary to avoid causing foreign substances to fall inside the battery cells 20 during the process of forming the liquid injection path, causing the electrolyte inside the battery cells to Doped with impurities. Similarly, for the first-time processing and production of battery cells, impurities such as debris on the end caps should also be avoided as much as possible. In the embodiment of the present application, a first recessed portion 211 is formed on the side of the end cover 21 away from the housing, the thickness of the bottom wall of the first recessed portion 211 is smaller than the thickness of the surrounding end caps, and the first recessed portion 211 does not go through the end. Cover 21, that is, in the embodiment of the present application, the first recessed part 211 is formed on the end cover by cutting tool processing. Since the first recessed part does not penetrate the end cover 21, the debris formed during the cutting process will not dropped into the inside of the battery cell 20 .

The liquid injection structure 212 is formed by piercing the bottom wall of the first recessed portion 211 from the surface away from the housing 22 towards the inside of the housing 22 . After forming the first recessed portion 211 on the end cap 21, the thickness of the bottom wall of the first recessed portion 211 on the end cap 12 becomes relatively thin, in order to avoid chipping when the liquid injection structure 212 is continuously formed by cutting Dropped into the housing, in the embodiment of the present application, the liquid injection structure 211 is formed by piercing the bottom wall of the first recess 211 toward the inside of the housing 22 with a needle or other sharp tools. When the bottom wall of the first recessed part 211 is pierced by a puncture needle or other sharp objects, the bottom wall of the first recessed part 211 will bend toward the inside of the housing 22 along with the piercing tool to form a liquid injection structure 211. Among them, due to the characteristics of the material of the end cap 21 , the pierced part of the bottom wall will not be cut off and fall into the housing 22 , but will continue to be connected with the bottom wall of the first recess 211 . In this way, during the process of piercing the end cap 21 , it is avoided that debris falls into the casing, causing impurities to be mixed into the electrolyte. Wherein, the liquid injection structure 212 formed by piercing can be in various shapes, such as: circular, square or elliptical, etc., which are not limited here.

By forming a first recess 211 on the end cap 21, and then forming a liquid injection structure on the bottom wall of the first recess 211 in a piercing manner, the first recess 211 and the liquid injection structure 212 are jointly formed on the end cap 21. A liquid injection path is formed, through which the battery cells can be conveniently injected with liquid. After the liquid injection is completed, the liquid injection path is sealed by the sealing part 24 , so that the service life of the battery cells can be extended.

Therefore, through the above method, in order to avoid debris falling into the battery cell when the liquid injection path is formed on the end cap 21, and to reduce the difficulty of opening a liquid injection path on the end cap 21, the embodiment of the present application adopts the The cover 21 is provided with a first recessed portion 211 away from the surface of the housing 22, so that the thickness of the bottom wall of the first recessed portion 211 is smaller than the thickness of the surrounding end cover 21. When the direction inside the housing 22 pierces the bottom wall, the bottom wall structure bends inward to form a liquid injection structure 212, so that the components of the end cover 21 will not be cut or worn away, thereby effectively avoiding the occurrence of leakage during the opening of the liquid injection path. Impurities fall into the casing 22 and affect the environment of the internal electrolyte. The liquid injection path is sealed by setting the sealing part 24 to ensure that the inside of the battery cell 20 can still be well sealed after liquid injection.

Please continue to refer to FIG. 4 , according to some embodiments of the present application, the section of the liquid injection structure 212 is arranged in an inverted "eight" shape on a plane perpendicular to the end cap 21 .

Specifically, the liquid injection structure 212 is formed by piercing the bottom wall of the first recessed portion 211 so that the bottom wall of the first recessed portion 211 is bent inwardly of the housing 22, and the liquid injection structure 212 is formed on a plane perpendicular to the end cap 21. The upper section is in the shape of an inverted "eight". The cross-section of the inverted "eight"-shaped liquid injection structure in the horizontal direction can be a circle, a direction or an ellipse, which is not limited here, and can be in any shape, as long as it can facilitate the passage of the electrolyte and stimulate It is sufficient that the material at the bend formed after wearing does not fall off easily. At the same time, in order to form an inverted "eight"-shaped section, the end of the piercing tool needs to have a certain radian. In this way, the bottom wall of the first recess 211 can be deformed slowly when piercing, which is not easy Cause the bottom wall material to fall, can play a better effect of preventing debris from falling.

By setting the section of the liquid injection structure 212 in an inverted "eight" shape on a plane perpendicular to the end cap 21, the first recessed part 211 and the liquid injection structure 212 together form a funnel-shaped liquid injection path, and the liquid injection structure 212 It can guide the electrolyte solution injected in the liquid injection path.

Please continue to refer to FIG. 4 , according to some embodiments of the present application, the sealing portion 24 is disposed in the first recessed portion 211 and is sealingly connected with the first recessed portion 211 .

As shown in FIG. 4 , the sealing part 24 can be a metal structure covered in the first recessed part 211, and by welding the edge of the sealing part 24 to the inner wall of the first recessed part 211, the liquid injection path and Sealing of the inside of the battery cell 20 .

In other embodiments, the sealing part 24 can also be an elastic plastic structure, and the sealing connection with the first recessed part 211 can be realized through sealant or interference fit.

Please refer to FIG. 5 , which shows the structure of the sealing part 24 in the battery cell 20 provided by another embodiment of the present application. In some embodiments, the sealing part 24 may also be disposed in the liquid injection structure 212 and be sealed with the liquid injection structure 212 . The liquid injection path is sealed by sealing the sealing portion 24 on the inner wall of the liquid injection structure 212 .

Please refer to FIG. 6 , which shows the structure of the sealing part 24 in the battery cell 20 provided by another embodiment of the present application. In some other embodiments, the sealing part 24 can also be provided on the first recessed part 211 and the liquid injection structure 212 simultaneously. By setting the cross-section of the sealing part 24 in a "T" shape, the sealing of the first recessed part 211 and the liquid injection structure 212 can be realized at the same time, and the sealing performance can be further improved.

By sealing the sealing part 24 in the first recessed part 211 and/or the liquid injection structure 212 , the sealing of the inside of the battery cell 20 after the electrolyte solution is injected is realized, ensuring the stability of the subsequent operation of the battery cell 20 .

Please refer to FIG. 7 , which shows the structure of the end cover 21 in the battery cell 20 provided by another embodiment of the present application. According to some embodiments of the present application, a second recessed portion 213 is formed on the side of the end cover 21 away from the housing 22, the first recessed portion 211 is formed on the bottom wall of the second recessed portion 213, and the sealing portion 24 is disposed on the second recessed portion 213. Inside the two recesses 213 .

In order to make the configuration of the liquid injection path more diversified, by forming a second recessed part 213 on the side of the end cover 21 away from the housing 22, the first recessed part 211 is formed on the bottom wall of the second recessed part 213, that is, the second recess Sleeved on the first recessed part, when the first recessed part 211 and the second recessed part 213 are cylindrical, the diameter of the second recessed part 213 is greater than the diameter of the first recessed part 211 . Cross-sections of the second recessed portion 213 and the first recessed portion 211 form a trapezoidal structure. In this way, a step is formed between the second recessed part 211 and the first recessed part 213 , and through the step, the sealing part 24 can be better arranged, and the liquid injection path can be better sealed.

In Fig. 7, the sealing part 24 is arranged in the second recessed part 213, so that the sealing contact is formed between the sealing part 24 and the side wall and the bottom wall of the second recessed part 213, compared with the sealing part 24 arranged in the first In terms of the recessed portion 211 or the liquid injection structure 212, the sealing contact area is increased, thereby further improving the sealing performance.

According to some embodiments of the present application, the edge of the sealing part 24 is welded to the second concave part 213 .

The welding method can melt the edge of the sealing part 24 and then weld and fix it with the side wall of the second recessed part 213 , so as to achieve a good sealing effect.

By welding the edge of the sealing portion 24 to the second recessed portion 213 , the sealing of the liquid injection path by the sealing portion 24 is realized, thereby ensuring the tightness of the inner space of the battery cell 20 . Simultaneously because the first recessed part 211 is formed in the bottom wall of the second recessed part 213, thus when the structure melting of the edge of the sealing part 214 flows into the gap between the second recessed part 213, the melted structure flowing in is in the second recessed part 213 The bottom wall of the sealing portion 214 is limited and stopped, which can effectively prevent the molten structure of the edge of the sealing portion 214 from flowing into the battery cell 20 and affecting the electrolyte.

Please refer to 7 again, according to some embodiments of the present application, a groove 241 is provided at the end of the sealing portion 24 facing away from the housing 22 , and the groove 241 is used to release the stress generated by welding.

When the sealing part 24 is sealed and welded with the first concave structure 211, the second concave structure 213 or the liquid injection structure 212, the parts to be welded are first melted and then solidified and welded. The limitation of the structure will produce welding stress. Please refer to FIG. 8 , which shows the structure after the sealing part 24 and the second recessed part 213 shown in FIG. 7 are welded. Groove 241, so that part of the structure that melts when the edge of sealing part 24 is welded flows and fills between the side wall of sealing part 24 and second recessed part 213, and another part flows in groove 241, so that the edge of sealing part 24 melts The structure will not be restricted by other structures during the solidification process, thereby ensuring that the welding stress can be released and enhancing the structural stability of the sealing portion 24 after welding.

According to some embodiments of the present application, the sealing part 24 is in sealing connection with the second recessed part 213 through a sealant.

Specifically, after the sealing part 24 is placed in the second recessed part 213, a sealant can be injected into the gap between the edge of the sealing part 24 and the side wall of the second recessed part 213, and the sealant is filled in the gap and dried and cured. Afterwards, the sealing part 24 is sealed and fixed in the second recessed part 213 to ensure the sealing performance inside the battery cell 20 .

According to another aspect of the embodiments of the present application, there is also provided a battery, including the battery cell 20 in any of the above embodiments.

In some embodiments of the present application, the battery can be used not only as an operating power source for the vehicle, but also as a driving power source for the vehicle, replacing or partially replacing fuel or natural gas to provide driving power for the vehicle.

According to another aspect of the embodiments of the present application, there is also provided an electric device, including the above-mentioned battery, and the battery is used to provide power.

Electric devices can be but not limited to mobile phones, tablets, laptops, electric toys, electric tools, battery cars, electric cars, ships, spacecraft, etc. Among them, electric toys may include fixed or mobile electric toys, such as game consoles, electric car toys, electric boat toys, electric airplane toys, etc., and spacecraft may include airplanes, rockets, space shuttles, spaceships, etc.

Finally, it should be noted that: the above embodiments are only used to illustrate the technical solutions of the present application, and are not intended to limit it; although the application has been described in detail with reference to the foregoing embodiments, those of ordinary skill in the art should understand that: It is still possible to modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some or all of the technical features; and these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the technical solutions of the various embodiments of the present application. All of them should be covered by the scope of the claims and description of the present application. In particular, as long as there is no structural conflict, the technical features mentioned in the various embodiments can be combined in any manner. The present application is not limited to the specific embodiments disclosed herein, but includes all technical solutions falling within the scope of the claims.

Claims

A battery cell, comprising:

a housing having an opening;

An end cover, the cover is arranged at the opening, a first recess is formed on the side of the end cover away from the housing, the thickness of the bottom wall of the first recess is smaller than the thickness of the surrounding end cover; A liquid injection structure is provided on the bottom wall of the first recess, and the liquid injection structure pierces from a surface of the bottom wall of the first recess that is far away from the housing toward the interior of the housing. The bottom wall is formed; the first recess and the liquid injection structure form a liquid injection path;

The sealing part seals the liquid injection path.
The battery cell according to claim 1, wherein, on a plane perpendicular to the end cap, a section of the liquid injection structure is arranged in an inverted "eight" shape.
The battery cell according to claim 1, wherein the sealing portion is disposed in the first recess and is sealingly connected with the first recess.
The battery cell according to claim 1, wherein the sealing part is disposed in the liquid injection structure and is sealedly connected with the liquid injection structure.
The battery cell according to any one of claims 1 to 4, wherein a second recess is formed on the side of the end cover away from the housing, and the first recess is formed on the first On the bottom wall of the second concave part; the sealing part is arranged in the second concave part.
The battery cell according to claim 5, wherein an edge of the sealing part is welded to the second concave part.
The battery cell according to claim 6, wherein a groove is provided at an end of the sealing portion away from the casing, and the groove is used for releasing stress generated by welding.
The battery cell according to claim 5, wherein the sealing part is sealed and connected to the second recessed part through a sealant.
A battery, comprising the battery cell according to any one of claims 1-8.
An electrical device, comprising the battery according to claim 9, the battery is used to provide power.