Battery cell, manufacturing method and manufacturing system thereof, battery, and power-using device

Abstract

To provide a battery cell, manufacturing method and manufacturing system thereof, a battery, and a power-using device that enhance the safety of the battery cell.SOLUTION: A battery cell includes: a casing 20 having an opening 21; an electrode assembly 11 housed in the casing and provided with a first lug 12 at one end facing the opening; and an end cap 30 covering the opening and including a cap body provided with a fragile portion and a first protrusion connected to the cap body. The end cap is configured such that when an internal pressure of the battery cell reaches a threshold, the fragile portion bursts to release the internal pressure. The first protrusion protrudes from the cap body along a direction facing the electrode assembly, supports the first lug, and forms an evacuation gap G between the first lug and the cap body for evacuation of the fragile portion. The present application can improve safety performance of the battery cell by reducing a risk that the first lug presses the fragile portion.SELECTED DRAWING: Figure 5

Description

[Technical field]

[0001] The present application relates to the technical field of batteries, and more particularly to individual batteries, methods and systems for manufacturing the same, batteries and power-using devices. [Background technology]

[0002] The battery unit is widely used in electronic devices, such as mobile phones, notebook computers, electric bicycles, electric cars, electric airplanes, electric boats, electric toy cars, electric toy boats, electric toy airplanes, and electric tools. The battery unit includes a cadmium-nickel battery unit, a nickel-hydrogen battery unit, a lithium-ion battery unit, and an alkaline zinc-manganese secondary battery unit.

[0003] In the development of battery technology, in addition to improving the performance of the battery itself, safety issues cannot be ignored. If the safety issues of the battery itself are not addressed, the battery itself cannot be used. Therefore, how to improve the safety of the battery itself is an urgent technical issue in battery technology. Summary of the Invention

[0004] The present application provides a battery unit that enhances the safety of the battery unit, a manufacturing method and manufacturing system thereof, a battery, and an electric power-using device.

[0005] According to a first aspect, a battery unit according to an embodiment of the present application includes a casing having an opening, an electrode assembly housed in the casing and having a first lug at one end facing the opening, and an end cap covering the opening, the end cap including a cap body having a weak portion and a first protrusion connected to the cap body, the end cap being configured to burst along the weak portion to release the internal pressure when the internal pressure of the battery unit reaches a threshold value. The first protrusion protrudes from the cap body in a direction facing the electrode assembly to support the first lug, and a retraction gap for retracting the weak portion is formed between the first lug and the cap body.

[0006] In the above solution, the first protrusion protruding from the cap body supports the first lug, reducing the degree of shaking of the electrode assembly when the battery alone vibrates, thereby improving the stability of the electrode assembly. The first protrusion supports the first lug, and a retraction gap for retracting the weak portion is formed between the first lug and the cap body, reducing the risk that the electrode assembly presses the weak portion, reducing the possibility of the weak portion breaking down, and improving the safety of the battery alone.

[0007] In some embodiments, a first recess is formed in the end cap at a position corresponding to the first protrusion, the first recess being recessed from the outer surface of the cap body in a direction facing the electrode assembly, and the bottom surface of the first recess is closer to the first lug than the inner surface of the cap body.

[0008] The above solution ensures the degree to which the first protrusion protrudes from the cap body, effectively supports the first lug, increases the retraction gap dimension in the thickness direction, and reduces the risk of the electrode assembly pressing the weak part. At the same time, the embodiment of the present application ensures the degree of recession of the first recessed part under the premise of ensuring the degree of protrusion of the first protrusion, thereby increasing the elasticity of the first protrusion and reducing the risk of the first protrusion crushing the first lug during wearing.

[0009] In some embodiments, the first protrusion abuts and is welded to the first lug to provide an electrical connection between the end cap and the first lug.

[0010] In the above solution, the end cap is directly electrically connected to the first lug via the first protrusion, which simplifies the structure of the battery unit.

[0011] In some embodiments, the battery unit further includes a current collecting member disposed between the end cap and the first lug. The current collecting member connects the end cap and the first lug to realize an electrical connection between the end cap and the first lug. A withdrawal gap is located between the current collecting member and the cap body in a thickness direction of the end cap.

[0012] Since the first protrusion protrudes from the cap body, the first protrusion separates the cap body and the first lug in the thickness direction, and when the end cap and the first lug are directly connected, the first lug is only connected to the first protrusion of the end cap, and the area for direct current transfer of the first lug may be limited by the first protrusion. In the above solution, the current collecting member is provided to connect the first lug and the end cap, and the area for direct current transfer of the first lug is not limited by the first protrusion, and the current of the first lug is concentrated on the end cap through the current collecting member, and the current collecting member reduces the difference in the conductive path between different areas of the first lug and the end cap, increases the uniformity of the current density of the first lug, reduces the internal resistance, and improves the overflow capacity and charging efficiency of the battery unit. The escape gap is located between the current collecting member and the cap body, which not only reduces the risk of the current collecting member pressing the thin part, but also reduces the possibility that the current collecting member will clog the exhaust passage when the thin part bursts, ensuring smooth exhaust and improving safety.

[0013] In some embodiments, a current collecting member covers the weakened portion along the thickness of the end cap to separate the weakened portion from the first lug.

[0014] In the above solution, the current collecting member can isolate the weak portion from the first lug, thereby reducing the active particles in the electrode assembly falling onto the weak portion, and reducing the risk of corrosion of the weak portion.

[0015] In some embodiments, a first protrusion is provided around the outside of the cap body, and a current collecting member is used to connect the cap body and the first lug to achieve an electrical connection between the end cap and the first lug.

[0016] In some embodiments, the current collecting member includes a first current collecting portion and a second current collecting portion connected to the first current collecting portion, the first current collecting portion is connected to the first lug to electrically connect the current collecting member to the first lug, and the second current collecting portion is connected to the cap body to electrically connect the current collecting member to the end cap. The first current collecting portion protrudes from a surface of the second current collecting portion facing the electrode assembly, and a recessed portion is formed at a position of the current collecting member corresponding to the first current collecting portion, the recessed portion being recessed from the surface of the second current collecting portion facing away from the electrode assembly in a direction toward the electrode assembly, so that a recessed gap is formed between the current collecting member and the cap body.

[0017] In the above-mentioned solution, the provision of the recessed portion forms a clearance gap to prevent the first current collecting portion from contacting the cap body, reducing the risk of the first current collecting portion pressing the weak portion, thereby improving safety. The first current collecting portion supports the central region of the first lug, and the first protruding portion supports the edge region of the first lug, thus equalizing the force applied to the first lug and reducing the risk of the lug of the electrode assembly being offset or displaced in the thickness direction.

[0018] In some embodiments, the first current collector is abutted and welded to the first lug and the second current collector is abutted and welded to the cap body.

[0019] In the above solution, the recess reduces the thickness of the first current collecting part, which reduces the welding force required to weld the first current collecting part and the first lug, thereby reducing heat generation and the risk of burn damage to other components.

[0020] In some embodiments, at least a portion of the current collecting member is located between the first protrusion and the first lug, and the first protrusion supports the first lug via the current collecting member.

[0021] In the above-mentioned solution, the first protrusion supports the first lug through the current collecting member, which reduces the degree of shaking of the electrode assembly when the battery unit is vibrated and enhances the stability of the electrode assembly, while at the same time supporting the current collecting member and forming a retraction gap between the current collecting member and the cap body.

[0022] In some embodiments, a portion of the current collecting member is welded to the first lug and another portion of the current collecting member is welded to the first protrusion.

[0023] In the above solution, the contact resistance between the current collecting member and the end cap and the contact resistance between the current collecting member and the first lug can be reduced by welding, and the eddy current capacity can be improved.

[0024] In some embodiments, the current collecting member is a flat plate structure.

[0025] In the above solution, the flat-plate-shaped current collecting member is easier to mold. The flat-plate-shaped current collecting member contacts the first lug as a whole, increasing the overflow area, and the current collecting member supports the first lug more uniformly, reducing the risk of the lug of the electrode assembly being offset or displaced in the thickness direction. The flat-plate-shaped current collecting member is completely isolated from the cap body, ensuring a clearance between the current collecting member and the cap body, and reducing the risk of contact between the current collecting member and the weak part.

[0026] In some embodiments, the first projection is disposed around the exterior of the cap body.

[0027] In some embodiments, the cap body is disposed around an exterior of the first projection.

[0028] In some embodiments, the end cap further includes a second protrusion disposed around an exterior of the cap body, the second protrusion protruding from an interior surface of the cap body in a direction toward the electrode assembly, an apex surface of the second protrusion being closer to the first lug than an apex surface of the first protrusion, and the second protrusion abutting against the first lug to support the first lug.

[0029] In the above solution, the first protrusion supports the central region of the first lug via the current collecting member, and the second protrusion supports the edge region of the first lug, thus making it possible to equalize the force applied to the first lug and reducing the risk of the lug of the electrode assembly being offset or misaligned in the thickness direction.

[0030] In some embodiments, a second recess is formed at a position corresponding to the second protrusion of the end cap, the second recess being recessed in a direction from the outer surface of the cap body toward the electrode assembly, and the bottom surface of the second recess is closer to the first lug than the inner surface of the cap body.

[0031] In the above solution, under the premise that the degree of protrusion of the second protrusion portion is ensured, the degree of recession of the second recessed portion can be further guaranteed, thereby increasing the elasticity of the second protrusion portion and reducing the risk of the second protrusion portion crushing the first lug during installation.

[0032] In some embodiments, an outer surface of the second projection abuts an inner surface of the casing and is welded to the casing to seal the opening.

[0033] In the above solution, the sealing is realized by welding, the risk of electrolyte leakage is reduced, and the connection strength and flow capacity between the second protrusion and the casing are improved. The strength of the second protrusion is reduced by the second recess, and the elasticity of the second protrusion is increased, so that the second protrusion is deformed during the welding process between the second protrusion and the casing to release the welding stress, thereby reducing the deformation and burst risk of the welding area and improving the sealing.

[0034] In some embodiments, the cap body is a flat plate structure.

[0035] In some embodiments, the cap body includes a main board body and a third protrusion, the main board body is disposed around an outer side of the third protrusion, the first protrusion is disposed around an outer side of the main board body, and the weak portion is formed in the third protrusion. The main board body includes a first inner surface and a first outer surface disposed opposite to each other, the first inner surface faces the electrode assembly, the first protrusion and the third protrusion protrude along a direction from the first inner surface toward the electrode assembly, a top end surface of the first protrusion is closer to the first lug than a top end surface of the third protrusion, and a retreat gap for retreating the weak portion is formed between the current collecting member and the third protrusion.

[0036] In the above solution, a third protrusion is provided in the middle of the end cap, which increases the strength of the end cap and reduces deformation of the end cap. Since the third protrusion is in a protruding state and is not easily deformed, providing a weak part in the third protrusion reduces creep of the weak part and reduces the risk of failure of the weak part. The above solution forms an escape gap between the third protrusion and the current collecting member, which reduces the risk of the current collecting member clogging the exhaust passage when the weak part bursts, realizing smooth exhaust and reducing safety risks.

[0037] In some embodiments, a third recessed portion is formed at a position corresponding to the third protrusion of the cap body, the third recessed portion being recessed in a direction from the first outer surface toward the electrode assembly, and a weak portion is formed in an area of ​​the third protrusion facing the bottom surface of the third recessed portion.

[0038] In the above solution, the weak portion is formed in an area facing the bottom surface of the third recess portion of the third protrusion portion, thereby reducing the distance between the weak portion and other external members and reducing the risk of the weak portion being crushed by external members.

[0039] In some embodiments, a groove is provided in the cap body and a weakened portion is formed in the cap body in an area opposite the groove.

[0040] In the above solution, the thickness and strength of the weakened portion is reduced by providing a groove, so that the end cap will burst along the weakened portion when the internal pressure of the battery unit reaches a threshold value.

[0041] In some embodiments, the end cap electrically connects the first lug and the casing.

[0042] In the above solution, the casing itself can be used as the output pole of the single battery. When multiple single batteries are installed, the casing is electrically connected to the bus member, which not only increases the flow area but also makes the design of the bus member structure more flexible.

[0043] In some embodiments, the casing includes a side wall and a bottom wall connected to the side wall, the side wall extends along the thickness direction of the end cap and is provided on the outer periphery of the electrode assembly, and the bottom wall is provided with an electrode lead-out hole. The electrode assembly further includes a second lug, the first lug and the second lug having opposite polarities and provided at both ends of the electrode assembly, respectively. The battery unit includes an electrode terminal attached to the electrode lead-out hole, and the electrode terminal is electrically connected to the second lug.

[0044] In the above solution, the bottom wall and the electrode terminals can be used as two output poles of the battery unit, simplifying the structure of the battery unit and ensuring the overflow capacity of the battery unit. When multiple battery units are installed, the bottom wall and the electrode terminals are located at the same end of the battery unit, and the bus members are installed on the same side of the battery unit, simplifying the installation process and improving the installation efficiency.

[0045] In some embodiments, the bottom wall and the side wall are integrally formed, which can omit the step of connecting the bottom wall and the side wall.

[0046] In some embodiments, the first lug is a negative lug and the base material of the casing is steel.

[0047] In the above solution, the casing and the negative electrode lug are electrically connected, that is, the casing is in a low potential state. The steel casing can reduce the risk of corrosion by the electrolyte in a low potential state, which reduces the safety risk.

[0048] In some embodiments, the base material of the casing and the base material of the end caps are the same, which can ensure the welding strength between the casing and the end caps and ensure the hermeticity of the battery unit.

[0049] In some embodiments, the battery cell is a cylindrical battery cell.

[0050] According to a second aspect, an embodiment of the present application provides a battery including a single battery according to any one of the embodiments of the first aspect.

[0051] According to a third aspect, an embodiment of the present application provides a power-using device including the battery of the second aspect for providing power energy.

[0052] According to a fourth aspect, an embodiment of the present application provides a method for manufacturing a single battery, the method comprising:

[0053] Providing a casing having an opening;

[0054] providing an electrode assembly, mounting the electrode assembly within the casing and providing a first lug on an end of the electrode assembly facing the opening;

[0055] preparing an end cap including a cap body having a weakened portion and a first protrusion connected to the cap body;

[0056] and connecting an end cap to the casing to cover the opening with the end cap;

[0057] Here, the end cap is configured such that when the internal pressure of the battery unit reaches a threshold value, the weak portion ruptures to release the internal pressure, and the first protrusion protrudes from the cap body along a direction facing the electrode assembly, supports the first lug, and forms an evacuation gap between the first lug and the cap body for the weak portion to retreat.

[0058] According to a fifth aspect, an embodiment of the present application provides a system for manufacturing a single battery, the system comprising:

[0059] a first preparation device for preparing a casing having an opening;

[0060] a second preparation device for preparing the electrode assembly, mounting the electrode assembly within the casing, and providing a first lug on one end of the electrode assembly toward the opening;

[0061] a third preparation device for preparing an end cap including a cap body having a weakened portion and a first protrusion connected to the cap body;

[0062] an assembly device for connecting the end cap to the casing and covering the opening with the end cap;

[0063] Here, the end cap is configured such that when the internal pressure of the battery unit reaches a threshold value, the weak portion ruptures to release the internal pressure, and the first protrusion protrudes from the cap body along a direction facing the electrode assembly, supports the first lug, and forms an evacuation gap between the first lug and the cap body for the weak portion to retreat. [Brief description of the drawings]

[0064] [Figure 1] 1 is a structural schematic diagram of a vehicle provided by some embodiments of the present application. [Diagram 2] FIG. 1 is an exploded schematic diagram of a battery provided according to some embodiments of the present application. [Diagram 3] FIG. 3 is an exploded schematic view of the battery module shown in FIG. [Figure 4] FIG. 2 is an exploded schematic diagram of a single battery provided by some embodiments of the present application. [Diagram 5] FIG. 2 is a cross-sectional schematic diagram of a battery unit provided by some embodiments of the present application. [Figure 6] 6 is an enlarged schematic view of the circled area A of the single battery shown in FIG. 5. [Figure 7] FIG. 2 is a cross-sectional schematic diagram of a battery unit provided according to some other embodiments of the present application. [Figure 8] 8 is an enlarged schematic view of the circular frame B of the single battery shown in FIG. 7. [Figure 9] FIG. 2 is a cross-sectional schematic diagram of a battery unit provided according to some other embodiments of the present application. [Figure 10] 10 is an enlarged schematic view of a section C of the battery unit shown in FIG. [Figure 11]1 is a schematic flow chart of a method for manufacturing a battery unit provided by some embodiments of the present application. [Figure 12] FIG. 1 is a schematic block diagram of a system for manufacturing a battery unit provided by some embodiments of the present application.

[0065] In the accompanying drawings, the drawings are not necessarily drawn to scale. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0066] In order to clarify the purpose, technical means and advantages of the embodiments of the present application, the technical means in the embodiments of the present application will be clearly described below with reference to the drawings in the embodiments of the present application, but it goes without saying that the described embodiments are only some of the embodiments of the present application, and are not all of the embodiments. Based on the embodiments in the present application, other embodiments obtained by those skilled in the art without creative labor are all included in the protection scope of the present application.

[0067] Unless otherwise defined, all technical and scientific terms used in this application have the same meaning as commonly understood by those skilled in the art of this application, and the terms used in the specification of this application are used only for the purpose of describing specific embodiments and are not intended to limit this application, and terms such as "include", "have" and their variations described in the specification and claims of this application and the above drawings are intended to include non-exclusive inclusions. Terms such as "first", "second" and the like in the specification and claims of this application or the above drawings are used only for the purpose of distinguishing different objects and are not intended to describe a specific order or priority relationship.

[0068] An "embodiment" as referred to in this application means that a particular feature, structure, or characteristic described in connection with the embodiment may be included in at least one embodiment of the application. The appearances of this phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are they necessarily referring to separate or alternative embodiments that are mutually exclusive of other embodiments.

[0069] In the description of this application, unless expressly specified and limited, it should be noted that the terms "attached", "connected", "coupled", and "attached" should be understood in a broad sense, for example, may be fixedly connected, may be detachably connected, may be integrally connected, may be directly connected or indirectly connected via an intermediate medium, may be internal communication between two components, etc. For those skilled in the art, the specific meaning of the above terms in this application can be understood according to the specific situation.

[0070] The term "and / or" in this application is merely intended to describe the relationship of related objects, for example, A and / or B has three meanings: A alone, both A and B, and B alone. Also, the character " / " in this application generally means that the related objects before and after it have an "or" relationship.

[0071] In the embodiments of the present application, the same reference numerals indicate the same components, and detailed descriptions of the same components in different embodiments are omitted for the sake of brevity. It should be understood that the dimensions such as thickness, length, width, etc. of various components in the embodiments of the present application shown in the accompanying drawings, as well as the overall thickness, length, width, etc. of the integrated device are merely illustrative and are not intended to limit the present application.

[0072] The term "plurality" as used in this application means two or more (including two).

[0073] In the present application, the battery unit includes a lithium ion secondary battery, a lithium ion primary battery, a lithium sulfur battery, a sodium lithium ion battery, a sodium ion battery, or a magnesium ion battery, etc., but is not particularly limited in the embodiments of the present application. The battery unit may be cylindrical, flat, rectangular or other shapes, but is not particularly limited in the embodiments of the present application.

[0074] The battery referred to in the embodiments of this application means a single physical module that includes one or more individual batteries to provide higher voltage and capacity. For example, the battery referred to in this application may include a battery module or a battery pack. The battery typically includes a box for enclosing one or more individual batteries. The box can prevent liquids and other foreign objects from affecting the charging or discharging of the individual batteries.

[0075] The battery unit includes an electrode assembly and an electrolyte, and the electrode assembly is composed of a positive electrode piece, a negative electrode piece, and a diaphragm. The battery unit mainly operates by the movement of metal ions between the positive electrode piece and the negative electrode piece. The positive electrode piece includes a positive electrode collector and a positive electrode active material layer, the positive electrode active material layer is applied to the surface of the positive electrode collector, the positive electrode collector without the positive electrode active material layer protrudes from the positive electrode collector with the positive electrode active material layer applied, and the positive electrode collector without the positive electrode active material layer is the positive electrode lug. Taking a lithium-ion battery as an example, the material of the positive electrode collector can be aluminum, and the positive electrode active material can be lithium cobalt oxide, lithium iron phosphate, ternary lithium, or lithium manganese oxide, etc. The negative electrode piece includes a negative electrode collector and a negative electrode active material layer, the negative electrode active material layer is applied to the surface of the negative electrode collector, the negative electrode collector without the negative electrode active material layer protrudes from the negative electrode collector with the negative electrode active material layer applied, and the negative electrode collector without the negative electrode active material layer is the negative electrode lug. The material of the negative electrode collector can be copper, and the negative electrode active material can be carbon or silicon, etc. In order to pass a large current without melting, the positive electrode lug is laminated in multiple layers, and the negative electrode lug is laminated in multiple layers. The material of the diaphragm can be PP (polypropylene) or PE (polyethylene), etc.

[0076] The battery unit includes a casing and end caps, the casing has an opening for accommodating the electrode assembly, the electrode assembly is mounted in the casing through the opening, and the end caps cover the opening of the casing to achieve a seal.

[0077] For a single battery, the main safety hazards come from the charging and discharging process, and are also affected by the appropriate environmental temperature design. In order to effectively avoid unnecessary losses, there are generally three types of battery protection measures. Specifically, the protection measures include at least a switching device, a suitable diaphragm material, and a pressure release mechanism. A switching device refers to a device for stopping the charging or discharging of a battery when the temperature or resistance inside the single battery reaches a certain threshold. The diaphragm is used to isolate the positive and negative electrode pieces, and when the temperature rises to a certain value, it automatically dissolves the micro-order (or nano-order) micro-holes attached on it, blocking the passage of metal ions through the diaphragm and terminating the internal reaction of the single battery.

[0078] The pressure release mechanism refers to a device or member that operates to release the internal pressure or temperature of the battery unit when the internal pressure or temperature of the battery unit reaches a predetermined threshold. This threshold can be designed according to design requirements. The threshold depends on one or more materials of the positive electrode piece, the negative electrode piece, the electrolyte, and the diaphragm in the battery unit.

[0079] The term "operation" as used herein means that the pressure release mechanism operates or is activated to a certain state to release the internal pressure and temperature of the battery unit. The operation of the pressure release mechanism includes, but is not limited to, at least a portion of the pressure release mechanism being broken, crushed, torn or opened. When the pressure release mechanism operates, high temperature and high pressure materials inside the battery unit are discharged from the operating portion to the outside as emissions. In this way, when the pressure or temperature can be controlled, the pressure of the battery unit can be released and the temperature can be lowered to prevent potential more serious accidents. The emissions from the battery unit as used herein include, but are not limited to, electrolyte, dissolved or split positive and negative electrode pieces, diaphragm fragments, high temperature and high pressure gas due to reaction, flames, etc.

[0080] The pressure release mechanism of a single battery has an important impact on the safety of the battery. For example, in the event of a short circuit or overcharging, thermal runaway may occur inside the single battery, causing a sudden rise in pressure or temperature. In such a case, the operation of the pressure release mechanism can release the internal pressure and temperature to the outside, preventing the single battery from exploding or catching fire.

[0081] The pressure release mechanism may take the form of an explosion-proof valve, a gas valve, a pressure release valve, a safety valve, etc., and more specifically, may take the form of a component or structure that is sensitive to pressure or temperature; that is, when the internal pressure or temperature of the battery unit reaches a certain threshold, the pressure release mechanism is activated or a weak structure provided in the pressure release mechanism is broken and cracked, forming an opening or passage for releasing the internal pressure or temperature.

[0082] In order to simplify the structure of the battery unit, the inventors have considered laminating a pressure release mechanism on the end cap. For example, the inventors have provided a weak portion on the end cap, and the end cap is configured to burst along the weak portion to release the internal pressure when the internal pressure of the battery unit reaches a threshold value. When a phenomenon such as a short circuit or overcharging occurs, thermal runaway occurs inside the battery unit and the pressure rises rapidly, the weak portion bursts to release the internal pressure to the outside, preventing the battery unit from disassembling and causing a fire, and improving safety.

[0083] However, according to the inventor's research, when the battery unit is vibrated, the lugs of the electrode assembly are likely to press or impact the weak portion, which may weaken the strength of the weak portion. If the weak portion is pressed or impacted by the lugs, it may burst when the internal pressure of the battery unit does not reach a threshold value, causing the battery unit to fail and posing a safety hazard.

[0084] In view of this, the embodiments of the present application provide the following technical solution, in which the end cap includes a cap body and a first protrusion connected to the cap body, the cap body is provided with a weak part, the first protrusion protrudes from the cap body along a direction toward the electrode assembly, supports the lug of the electrode assembly, and a retraction gap for retracting the weak part is formed between the lug and the cap body. A battery unit having such a structure reduces the risk that the electrode assembly presses the weak part, and improves the safety of the battery unit.

[0085] The technical solutions described in the embodiments of the present application can be applied to batteries and battery-powered devices.

[0086] The power-using device may be a vehicle, a mobile phone, a portable device, a notebook computer, a ship, a navigation device, an electric toy, an electric tool, etc. The vehicle may be a fuel-powered vehicle, a gas-powered vehicle, or a new energy vehicle, the new energy vehicle may be a pure electric vehicle, a hybrid vehicle, or a long-distance vehicle, etc., the navigation device may include an airplane, a rocket, a space shuttle, a spaceship, etc., the electric toy may include a stationary or mobile electric toy, such as a game machine, an electric car toy, an electric ship toy, and an electric airplane toy, etc., and the electric tool may include a metal cutting electric tool, a polishing electric tool, a mounted electric tool, and a railway electric tool, such as an electric drill, an electric sander, an electric spanner, an electric screwdriver, an electric hammer, an electric impact drill, a concrete vibrator, and an electric planer, etc. In the embodiment of the present application, the above-mentioned power-using device is not particularly limited.

[0087] In the following embodiment, for convenience of explanation, a case will be described in which the power consumption device is a vehicle.

[0088] Fig. 1 is a structural schematic diagram of a vehicle provided by some embodiments of the present application. As shown in Fig. 1, a battery 2 is provided inside the vehicle 1, and the battery 2 may be disposed at the bottom, front or rear of the vehicle 1. The battery 2 is used to supply power to the vehicle 1, for example, the battery 2 is used as an operating power source for the vehicle 1.

[0089] The vehicle 1 further includes a controller 3 and a motor 4, where the controller 3 controls the power supply from the battery 2 to the motor 4 and may be used, for example, for start-up, navigation and operating power usage requirements of the vehicle 1 during driving.

[0090] In some embodiments of the present application, the battery 2 is used as a driving power source for the vehicle 1 in addition to providing an operating power source for the vehicle 1, and provides driving power for the vehicle 1 by replacing part or all of the fuel or gas.

[0091] 2 is an exploded schematic diagram of a battery provided by some embodiments of the present application. As shown in FIG. 2, the battery 2 includes a case 5 and a battery unit (not shown in FIG. 2), and the battery unit is housed in the case 5.

[0092] The box 5 houses the battery unit, and the box 5 may have various structures. In some embodiments, the box 5 includes a first box portion 5a and a second box portion 5b, the first box portion 5a and the second box portion 5b are capped with each other, and the first box portion 5a defines an accommodation space 5c for accommodating the battery unit together with the second box portion 5b. The second box portion 5b has a hollow structure with an opening at one end, the first box portion 5a has a plate-like structure, the first box portion 5a covers the opening side of the second box portion 5b to form the box 5 having the accommodation space 5c, and the first box portion 5a and the second box portion 5b have a hollow structure with an opening at one end, and the opening side of the first box portion 5a covers the opening side of the second box portion 5b to form the box 5 having the accommodation space 5c. Of course, the first box-shaped portion 5a and the second box-shaped portion 5b may have various shapes, such as a cylindrical body or a rectangular parallelepiped.

[0093] In order to improve the sealing performance of the connection between the first box body portion 5a and the second box body portion 5b, a seal member such as a seal rubber or a seal ring may be provided between the first box body portion 5a and the second box body portion 5b.

[0094] When the first box body portion 5a covers the top of the second box body portion 5b, the first box body portion 5a may be called an upper box cover, and the second box body portion 5b may be called a lower box.

[0095] The battery 2 may have one or more battery units. When there are multiple battery units, the multiple battery units may be connected in series, parallel or a mixed connection, and a mixed connection may mean connecting multiple battery units in series and parallel. The multiple battery units are directly connected in series, parallel or a mixed connection, and the entirety of the multiple battery units is housed in the box 5, and of course, the multiple battery units are first connected in series, parallel or a mixed connection to form a battery module 6, and then the multiple battery modules 6 are connected in series, parallel or a mixed connection to be housed in the box 5 as a whole.

[0096] FIG. 3 is an exploded schematic view of the battery module shown in FIG.

[0097] 3, there are a plurality of battery units 7, and the plurality of battery units 7 are first connected in series, parallel or a mixed manner to form a battery module 6. The plurality of battery modules 6 are connected in series, parallel or a mixed manner and then housed as a whole in a box.

[0098] The plurality of battery units 7 in the battery module 6 are electrically connected to each other via bus members, and the plurality of battery units 7 in the battery module 6 are connected in parallel, in series or in a mixed manner.

[0099] Fig. 4 is an exploded schematic view of a battery unit provided by some embodiments of the present application. Fig. 5 is a cross-sectional schematic view of a battery unit provided by some embodiments of the present application. Fig. 6 is an enlarged schematic view of the circle A of the battery unit shown in Fig. 5.

[0100] 4 to 6, the battery unit 7 of the embodiment of the present application includes a casing 20 having an opening 21, an electrode assembly 10 housed in the casing 20 and provided with a first lug 12 at one end facing the opening 21, and an end cap 30 for covering the opening 21, the end cap 30 including a cap body 31 and a first protruding portion 32 connected to the cap body 31, the cap body 31 being provided with a weak portion 311, and the end cap 30 bursts along the weak portion 311 to release the internal pressure when the internal pressure of the battery unit 7 reaches a threshold value. The first protruding portion 32 protrudes from the cap body 31 in a direction toward the electrode assembly 10, supports the first lug 12, and forms an evacuation gap G between the first lug 12 and the cap body 31 for evacuation of the weak portion 311.

[0101] The electrode assembly 10 includes a first lug, a second lug and a diaphragm, and the diaphragm is used to isolate the first lug and the second lug. The first lug and the second lug have opposite polarities, in other words, one of the first lug and the second lug is a positive lug and the other of the first lug and the second lug is a negative lug.

[0102] Optionally, the first lug, the second lug and the diaphragm are all strip-shaped structures, and the first lug, the second lug and the diaphragm are wound together to form a wound structure, which may be a cylindrical structure, a flat structure or a structure of other shapes.

[0103] From the outside of the electrode assembly 10, the electrode assembly 10 includes a main body 11, a first lug 12, and a second lug 13, and the first lug 12 and the second lug 13 protrude from the main body 11. The first lug 12 is a portion of the first lug where an active material layer is not applied, and the second lug 13 is a portion of the second lug where an active material layer is not applied. Correspondingly, one of the first lug 12 and the second lug 13 is a positive polarity lug, and the other is a negative polarity lug.

[0104] The first lug 12 and the second lug 13 may extend from the same side of the body portion 11, or may extend from opposite sides.

[0105] Exemplarily, the first lug 12 and the second lug 13 are provided on both sides of the body portion 11, in other words, the first lug 12 and the second lug 13 are provided on both ends of the electrode assembly 10. Optionally, the first lug 12 is located at one end of the electrode assembly 10 facing the end cap 30, and the second lug 13 is located at one end of the electrode assembly 10 away from the end cap 30.

[0106] Alternatively, the first lug 12 is wound around the central axis X of the electrode assembly 10 in multiple turns, in other words, the first lug 12 includes multiple turns of lug layers. After winding is completed, the first lug 12 is generally columnar, and there is a gap between two adjacent turns of the lug layers. The embodiment of the present application processes the first lug 12 to reduce the gap between the lug layers, so as to easily connect the first lug 12 to other conductive structures. For example, the embodiment of the present application flattens the first lug 12 to gather the end region away from the main body 11 of the first lug 12, and the flattening process forms a dense end face at one end away from the main body 11 of the first lug 12, so as to reduce the gap between the lug layers, so as to easily connect the first lug 12 to other conductive structures. Alternatively, the embodiment of the present application may fill a conductive material between two adjacent turns of the lug layers to reduce the gap between the lug layers.

[0107] Optionally, the second lug 13 is wound in multiple turns around the central axis X of the electrode assembly 10, and the second lug 13 includes a lug layer having multiple turns. Illustratively, the second lug 13 is also flattened to reduce gaps between the lug layers of the second lug 13.

[0108] The casing 20 is a hollow structure open on one side, and an end cap 30 covers the opening 21 of the casing 20 to form a hermetic connection and define a receiving chamber for containing the electrode assembly 10 and the electrolyte.

[0109] The casing 20 has a hollow structure, and a space for accommodating the electrode assembly 10 is formed therein. The casing 20 may have various shapes, such as a cylinder or a rectangular parallelepiped. The shape of the casing 20 may be determined according to the specific shape of the electrode assembly 10. For example, if the electrode assembly 10 has a cylindrical structure, a cylindrical casing is adopted, and if the electrode assembly 10 has a rectangular parallelepiped structure, a rectangular parallelepiped casing is adopted.

[0110] The casing 20 includes a side wall 22 and a bottom wall 23, the side wall 22 being disposed around the outside of the electrode assembly 10, and the bottom wall 23 being connected to one end of the side wall 22. The side wall 22 has a tubular structure, e.g., the side wall 22 is a cylinder or a square tube, and the bottom wall 23 has a plate-like structure, the shape of which corresponds to the shape of the side wall 22. Optionally, an opening 21 is formed at one end of the side wall 22, and the bottom wall 23 is connected to one end of the side wall 22 remote from the opening 21.

[0111] The side wall 22 and the bottom wall 23 may be of unitary construction, i.e., the casing 20 may be a unitary molded piece, or, of course, the side wall 22 and the bottom wall 23 may be two separate pieces and connected by welding, riveting, adhesives, etc.

[0112] The end cap 30 may be electrically connected to the electrode assembly 10, or may be provided in an insulative manner on the electrode assembly 10. Optionally, the end cap 30 may be electrically connected to the first lug 12. Of course, the end cap 30 may be electrically connected to the first lug 12 directly, or may be electrically connected to the first lug 12 via another conductive member.

[0113] The casing 20 may be positively charged, negatively charged, or uncharged. When the casing 20 needs to be charged, the casing 20 may be connected directly to the lugs of the electrode assembly 10 or may be electrically connected to the lugs via other conductive members.

[0114] When the end cap 30 and the casing 20 are connected by welding, the end cap 30 and the casing 20 have the same polarity. For example, when the casing 20 is positively charged, the end cap 30 electrically connects the casing 20 to a lug of positive polarity, and when the casing 20 is negatively charged, the end cap 30 electrically connects the casing 20 to a lug of negative polarity. Of course, the casing 20 may be connected to the lug via other conductive structures, and is not particularly limited in this embodiment.

[0115] The casing 20 and end caps 30 may be formed from the same material or from different materials.

[0116] The cap body 31 has a plate-like structure and has an inner surface and an outer surface that are arranged opposite to each other along the thickness direction Z of the end cap 30, and the inner surface 31a of the cap body faces the electrode assembly 10. The inner surface 31a of the cap body may be a flat surface, a curved surface, or a combination of a flat surface and a curved surface. The outer surface 31b of the cap body may be a flat surface, a curved surface, or a combination of a flat surface and a curved surface. Optionally, the inner surface 31a of the cap body and the outer surface 31b of the cap body are arranged parallel to each other in a plane.

[0117] The weak portion 311 is a part of the cap body 31, and the strength of the weak portion 311 is smaller than that of other portions of the cap body 311. In this embodiment, the strength of the weak portion 311 can be reduced by reducing the thickness of the weak portion 311, changing the material of the weak portion 311, or by other methods.

[0118] The weak portion 311 may be provided in one turn around the central axis X of the electrode assembly 10, or may be provided in 1 / 2 turn, 2 / 3 turn, or 3 / 4 turn, etc. around the central axis, and is not particularly limited in this embodiment.

[0119] The first protrusion 32 protrudes from the inner surface 31a of the cap body in a direction toward the electrode assembly 10, and at least a part of the first protrusion 32 protrudes from the inner surface 31a of the cap body. In this embodiment, the degree to which the first protrusion 32 protrudes from the inner surface 31a of the cap body is not limited.

[0120] There may be one or more first protrusions 32. Optionally, when there are multiple first protrusions 32, the multiple first protrusions 32 may be spaced apart along the circumferential direction of the end cap 30.

[0121] The first protrusion 32 may abut against the first lug 12 and directly support the first lug 12, or, of course, the first protrusion 32 may indirectly support the first lug 12 by supporting another member.

[0122] In the thickness direction Z, a retraction gap G is located between the first lug 12 and the cap body 31. The retraction gap G is a space between the first lug 12 and the cap body 31 that is not filled with other solid members. The retraction gap G and the weak portion 311 face each other along the thickness direction Z, and serves to retract the weak portion 311.

[0123] Another member may be provided between the first lug 12 and the cap body 31, and the retraction gap G may separate this member from the thin portion 311. Of course, it is not necessary to provide another member between the first lug 12 and the cap body 31.

[0124] In this embodiment, the first protrusion 32 protruding from the cap body 31 supports the first lug 12, reducing the degree of shaking of the electrode assembly 10 when the single battery 7 vibrates, thereby improving the stability of the electrode assembly 10. The first protrusion 32 supports the first lug 12, and forms a retraction gap G between the first lug 12 and the cap body 31 for retracting the weak portion 311, thereby reducing the risk that the electrode assembly 10 presses the weak portion 311, reducing the possibility of failure of the weak portion 311, and improving the safety of the single battery 7.

[0125] In particular, when the end face of the first lug 12 having a winding structure that faces away from the main body 11 has low flatness and the end face of the first lug 12 presses the weak portion 311, the weak portion 311 will rupture more easily. In the present application, by providing the retraction gap G, the risk that the first lug 12 will press the weak portion 311 is reduced, and the possibility of failure of the weak portion 311 is reduced.

[0126] In some embodiments, the cap body 31 is provided with a groove 312, and the cap body 31 has a weakened portion 311 formed in a region facing the groove 312.

[0127] Alternatively, the groove 312 may be provided on the inner surface 31a of the cap body, and the weakened portion 311 is a portion located between the bottom surface of the groove 312 of the cap body 31 and the outer surface 31b of the cap body. Alternatively, the groove 312 may be provided on the outer surface 31b of the cap body, and the weakened portion 311 is a portion located between the bottom surface of the groove 312 of the cap body 31 and the inner surface 31a of the cap body.

[0128] In this embodiment, the groove 312 reduces the thickness and strength of the weak portion 311, and the end cap 30 bursts along the weak portion 311 when the internal pressure of the battery unit 7 reaches a threshold value.

[0129] In some embodiments, the groove 312 is provided on the inner surface 31a of the cap body. The groove 312 communicates with the evacuation gap G.

[0130] The groove 312 of this embodiment increases the distance between the thin portion 311 and the first lug 12 , and can reduce the risk that the first lug 12 presses against the thin portion 311 .

[0131] In some embodiments, the first lug 12 is electrically connected to the end cap 30 .

[0132] The end cap 30 is directly connected to the first lug 12 , for example, the end cap 30 is directly welded to the first lug 12 to achieve an electrical connection between the end cap 30 and the first lug 12 .

[0133] Alternatively, the end cap 30 may be indirectly connected to the first lug 12 via another conductive structure (e.g., a current collecting member described below). In this embodiment, the first protrusion 32 may be connected to the conductive structure, or the cap body 31 may be connected to the conductive structure.

[0134] In this embodiment, the end cap 30 is chargeable and can be used as an output electrode of the single battery 7, and one of the conventional electrode terminals can be omitted, simplifying the structure of the single battery 7.

[0135] In some embodiments, the end cap 30 is electrically connected to the first lug 12 and the casing 20 .

[0136] In this embodiment, the casing 20 itself can be used as the output pole of the single battery 7. When multiple single batteries 7 are installed, the casing 20 is electrically connected to the bus member, which not only increases the flow area but also allows for more flexible design of the bus member structure.

[0137] In some embodiments, the casing 20 includes a side wall 22 and a bottom wall 23 connected to the side wall 22, the side wall 22 extending along the thickness direction Z of the end cap 30 and provided around the outer periphery of the electrode assembly 10, and an electrode drawing hole 231 is provided in the bottom wall 23. The electrode assembly 10 further includes a second lug 13, and the polarities of the first lug 12 and the second lug 13 are opposite and are located at both ends of the electrode assembly 10, respectively. The battery unit 7 includes an electrode terminal 40 attached to the electrode drawing hole 231, and the electrode terminal 40 is electrically connected to the second lug 13.

[0138] The second lug 13 may be directly electrically connected to the electrode terminal 40, or may be indirectly electrically connected to the electrode terminal 40 via another conductive structure.

[0139] The electrode terminal 40 is provided on the bottom wall 23 in an insulative manner, the electrode terminal 40 and the bottom wall 23 have different polarities, and the electrode terminal 40 and the bottom wall 23 can be used as two output poles of the single battery 7, respectively.

[0140] When the first lug 12 is a negative lug and the second lug 13 is a positive lug, the bottom wall 23 is a negative output pole of the battery unit 7, and the electrode terminal 40 is a positive output pole of the battery unit 7. When the first lug 12 is a positive lug and the second lug 13 is a negative lug, the bottom wall 23 is a positive output pole of the battery unit 7, and the electrode terminal 40 is a negative output pole of the battery unit 7.

[0141] The electrode terminal 40 is fixed to the bottom wall 23. The electrode terminal 40 may be fixed to the outside of the bottom wall 23 as a whole, or may extend into the inside of the casing 20 through the electrode lead-out hole 231.

[0142] The first lug 12 is located at one end of the electrode assembly 10 facing the end cap 30, and electrically connects the end cap 30 and the first lug 12, and correspondingly, the second lug 13 is located at one end of the electrode assembly 10 facing the bottom wall 23, and electrically connects the electrode terminal 40 and the second lug 13. In the embodiment of the present application, the first lug 12 and the second lug 13 are provided at both ends of the electrode assembly 10, which can reduce the risk of electrical conduction between the first lug 12 and the second lug 13 and increase the overflow area of ​​the first lug 12 and the overflow area of ​​the second lug 13.

[0143] In this embodiment, the bottom wall 23 and the electrode terminal 40 can be used as two output poles of the battery unit 7, simplifying the structure of the battery unit 7 and ensuring the overflow capacity of the battery unit 7. The bottom wall 23 and the electrode terminal 40 are located at the same end of the battery unit 7, and when multiple battery units 7 are installed, the bus members are installed on the same side of the battery unit 7, simplifying the installation process and improving installation efficiency.

[0144] In some embodiments, the bottom wall 23 and the side wall 22 are integrally provided. In this embodiment, the step of connecting the bottom wall 23 and the side wall 22 can be omitted. The casing 20 can be formed by a drawing process.

[0145] The electrode extraction holes 231 in the embodiment of the present application are formed after the casing 20 is stretch formed.

[0146] The inventors came up with the idea of ​​pressing the open end of the casing with a roll, folding the open end of the casing inward to form a folded structure, and fixing the end cap by the folded structure pressing the end cap. The inventors attached electrode terminals to the end cap, and used the folded structure and the electrode terminals as two output poles of the battery unit. However, the larger the dimensions of the folded structure, the higher the risk of curling or wrinkling after molding. If the folded structure is curled or wrinkled, the surface of the folded structure will not be flat, and if the folded structure is welded to a bus member, there will be a problem of poor welding. Therefore, the dimensions of the folded structure are limited, and the overflow capacity of the battery unit is insufficient.

[0147] In this embodiment, electrode lead-out holes 231 for mounting electrode terminals 40 are formed in the bottom wall 23 by a drilling process, and the positive output electrode and the negative output electrode are provided at one end of the single battery 7 away from the opening 21, and the bottom wall 23 is formed during the molding process of the casing 20, so that the flatness of the bottom wall 23 can be ensured even when the electrode lead-out holes 231 are drilled, and the connection strength between the bottom wall 23 and the bus member can be guaranteed. At the same time, the flatness of the bottom wall 23 is not limited by its own dimensions, so that the bottom wall 23 has a relatively large dimension, which enhances the overflow capacity of the single battery 7.

[0148] In some embodiments, the first lug 12 is a negative lug and the base material of the casing 20 is steel.

[0149] The casing 20 is electrically connected to the negative lug, that is, the casing 20 is in a low potential state. The steel casing 20 can avoid corrosion by the electrolyte under a low potential state, which reduces safety risks.

[0150] In some embodiments, the casing 20 is welded to the end cap 30. The welding provides a connection between the casing 20 and the end cap 30, which can improve the sealing as well as increase the flow capacity between the casing 20 and the end cap 30.

[0151] In some embodiments, the base material of the casing 20 is the same as the base material of the end caps 30. Optionally, the base material of the casing 20 is steel.

[0152] In this embodiment, the base material of the casing 20 and the base material of the end caps 30 are the same, so that the welding strength between the casing 20 and the end caps 30 is ensured and the hermeticity of the single battery 7 can be guaranteed.

[0153] In some embodiments, the battery unit 7 is a cylindrical battery unit. Correspondingly, the electrode assembly 10 is a cylindrical structure, and the casing 20 is a cylindrical hollow structure.

[0154] In some embodiments, a first recess 33 is formed at a position corresponding to the first protrusion 32 of the end cap 30, recessed in a direction from the outer surface 31b of the cap body toward the electrode assembly 10, and the bottom surface of the first recess 33 is closer to the first lug 12 than the inner surface 31a of the cap body.

[0155] The first recess 33 reduces the strength of the first protrusion 32 and increases the elasticity of the first protrusion 32. During the process of the first protrusion 32 extending into the casing 20 and abutting against the first lug 12, the first protrusion 32 can release stress through deformation, reduce the impact force, and reduce the risk of the first lug 12 being crushed.

[0156] The first recess 33 and the first protrusion 32 are formed by pressing the end cap 30. As the first recess 33 becomes larger along the depth in the thickness direction Z, the degree to which the first protrusion 32 protrudes from the inner surface 31a of the cap body also increases, and the retraction gap G also increases.

[0157] In the embodiment of the present application, the degree of protrusion of the first protrusion 32 from the cap body 31 is guaranteed, the first lug 12 can be supported more effectively, the dimension of the retraction gap G along the thickness direction Z is increased, and the risk of the electrode assembly 10 pressing the weak contact portion 311 can be reduced. At the same time, in the embodiment of the present application, under the premise of ensuring the degree of protrusion of the first protrusion 32, the degree of recession of the first recess 33 can be further guaranteed, the elasticity of the first protrusion 32 can be increased, and the risk of the first protrusion 32 crushing the first lug 12 during the installation process can be reduced.

[0158] Optionally, the bottom surface of the first recessed portion 33 is flat and parallel to the inner surface 31a of the cap body.

[0159] In some embodiments, the battery unit 7 further includes a current collecting member 50 provided between the end cap 30 and the first lug 12. The current collecting member 50 connects the end cap 30 and the first lug 12 and electrically connects the end cap 30 and the first lug 12. A retraction gap G is located between the current collecting member 50 and the cap body 31 in the thickness direction Z of the end cap 30.

[0160] The current collecting member 50 is connected to the first lug 12 by welding, adhesive or other method to provide an electrical connection with the first lug 12. The current collecting member 50 is connected to the end cap 30 by welding, adhesive or other method to provide an electrical connection with the end cap 30.

[0161] The current collecting member 50 may be connected to the first protrusion 32 , to the cap body 31 , or to another portion of the end cap 30 .

[0162] Since the first protrusion 32 protrudes from the cap body 31, the first protrusion 32 separates the cap body 31 and the first lug 12 in the thickness direction Z, and when the end cap 30 and the first lug 12 are directly connected, the first lug 12 is only connected to the first protrusion 32 of the end cap 30. When the first protrusion 32 and the first lug 12 are directly connected, only the portion of the first lug 12 facing the first protrusion 32 is directly connected to the first protrusion 32, and the area for directly transferring current of the first lug 12 is limited by the first protrusion 32, and the overflow area between the first protrusion 32 and the first lug 12 is insufficient, and the current on the portion of the first lug 12 facing the cap body 31 in the thickness direction Z must first flow to the portion welded to the first protrusion 32 of the first lug 12 and then flow to the first protrusion 32, so the difference in the conductive path between different regions of the first lug 12 and the end cap 30 becomes large, which adversely affects the overflow capacity and charging efficiency of the battery unit 7.

[0163] In the embodiment of the present application, the current collecting member 50 is provided to connect the first lug 12 and the end cap 30, and the area for directly transferring current of the first lug 12 is no longer limited by the first protrusion 32. The current of the first lug 12 is collected at the end cap 30 through the current collecting member 50. The current collecting member 50 reduces the difference in the conductive path between different areas of the first lug 12 and the end cap 30, increases the uniformity of the current density of the first lug, reduces the internal resistance, and improves the overflow capacity and charging efficiency of the battery unit 7.

[0164] In this embodiment, the evacuation gap G is located between the current collecting member 50 and the cap body 31, which reduces the risk of the current collecting member 50 pressing the weak portion 311 and reduces the possibility of the current collecting member 50 clogging the exhaust passage when the weak portion 311 bursts, thereby ensuring smooth exhaust and improving safety.

[0165] In some embodiments, the current collecting member 50 covers the thinned portion 311 along the thickness direction Z of the end cap 30 to separate the thinned portion 311 from the first lug 12 .

[0166] A part of the current collecting member 50 and the weak portion 311 are provided with a gap between them along the thickness direction Z and cover the weak portion 311. The projection of the weak portion 311 along the thickness direction Z is included within the projection of the current collecting member 50 along the thickness direction Z.

[0167] In this embodiment, the current collecting member 50 separates the weak portion 311 from the first lug 12, which can reduce the amount of active particles in the electrode assembly 10 that fall onto the weak portion 311, and reduce the risk of corrosion of the weak portion 311.

[0168] In some embodiments, at least a portion of the current collecting member 50 is located between the first protrusion 32 and the first lug 12. The first protrusion 32 supports the first lug 12 via the current collecting member 50.

[0169] The first protrusion 32 supports the first lug 12 via the current collecting member 50, reducing the degree of shaking of the electrode assembly 10 when the battery unit 7 vibrates and increasing the stability of the electrode assembly 10. At the same time, the first protrusion 32 supports the current collecting member 50 and forms a retraction gap G between the current collecting member 50 and the cap body 31.

[0170] In some embodiments, a portion of the current collecting member 50 abuts and is welded to the first lug 12 and another portion of the current collecting member 50 abuts and is welded to the first protrusion 32 .

[0171] When installing the battery unit 7, first the current collecting member 50 is abutted against the first lug 12 and welded to form a first welded joint W1, and then the end cap 30 and the current collecting member 50 are welded to form a second welded joint W2.

[0172] In this embodiment, two different parts of the collecting member 50 are welded to the end cap 30 and the first lug 12, respectively, thereby reducing the welding risk of the first welded joint W1 and the second welded joint W2, and ensuring the connection strength between the collecting member 50 and the first lug 12 and the connection strength between the end cap 30 and the collecting member 50.

[0173] Welding reduces the contact resistance between the current collecting member 50 and the end cap 30 and between the current collecting member 50 and the first lug 12, and increases the eddy current capacity.

[0174] In some embodiments, current collecting member 50 is a flat plate structure.

[0175] The flat plate-shaped current collecting member 50 can be more easily formed. The flat plate-shaped current collecting member 50 contacts the first lug 12 as a whole, increasing the overflow area, and the current collecting member 50 supports the first lug 12 more uniformly, reducing the risk of the electrode assembly 10 being offset or displaced in the thickness direction Z of the lug. The flat plate-shaped current collecting member 50 is completely isolated from the cap body 31, ensuring the escape gap G between the current collecting member 50 and the cap body 31, reducing the risk of contact between the current collecting member 50 and the thin portion 311.

[0176] In some embodiments, the cap body 31 is disposed around the outside of the first protrusion 32. In other words, the cap body 31 is an annular structure disposed around the outside of the first protrusion 32.

[0177] In some embodiments, the end cap 30 further includes a second protrusion 34, which is provided around the outside of the cap body 31. The second protrusion 34 protrudes from the inner surface 31a of the cap body in a direction toward the electrode assembly 10, and the top surface of the second protrusion 34 is closer to the first lug 12 than the top surface of the first protrusion 32, and the second protrusion 34 abuts against the first lug 12 to support the first lug 12.

[0178] The second protrusion 34 is an annular structure provided around the outside of the cap body 31. The top surface of the first protrusion 32 abuts against the current collecting member 50, and optionally the top surface of the first protrusion 32 is flat. The top surface of the second protrusion 34 abuts against the first lug 12, and optionally the top surface of the second protrusion 34 is flat or curved.

[0179] The second protrusion 34 and the current collecting member 50 are spaced apart from each other to avoid the second protrusion 34 interfering with the contact between the current collecting member 50 and the first protrusion 32 and to ensure that the first protrusion 32 is in close contact with the current collecting member 50. Optionally, the second protrusion 34 is provided around the outside of the current collecting member 50.

[0180] The degree to which the second protrusion 34 protrudes from the inner surface 31a of the cap body is greater than the degree to which the first protrusion 32 protrudes from the inner surface 31a of the cap body, and the top surface of the second protrusion 34 is closer to the first lug 12 than the top surface of the first protrusion 32.

[0181] In this embodiment, the first protrusion 32 supports the central region of the first lug 12 via the collecting member 50, and the second protrusion 34 supports the edge region of the first lug 12, thereby equalizing the force applied to the first lug 12 and reducing the risk of the lug of the electrode assembly 10 being offset or shifted in the thickness direction Z.

[0182] In some embodiments, a second recess 35 is formed at a position corresponding to the second protrusion 34 of the end cap 30, recessed in a direction from the outer surface 31b of the cap body toward the electrode assembly 10, and the bottom surface of the second recess 35 is closer to the first lug 12 than the inner surface 31a of the cap body.

[0183] The second recess 35 reduces the strength of the second protrusion 34 and increases the elasticity of the second protrusion 34. During the process of the second protrusion 34 extending into the casing 20 and abutting against the first lug 12, the second protrusion 34 can release stress through deformation, reduce the impact force, and reduce the risk of the first lug 12 being crushed.

[0184] The second recessed portion 35 and the second protruding portion 34 are formed by pressing the end cap 30. As the depth of the second recessed portion 35 in the thickness direction Z increases, the degree to which the second protruding portion 34 protrudes from the inner surface 31a of the cap body also increases.

[0185] In the embodiment of the present application, under the premise of ensuring the protrusion degree of the second protrusion portion 34, the recession degree of the second recess portion 35 can be ensured, the elasticity of the second protrusion portion 34 can be increased, and the risk of the second protrusion portion 34 crushing the first lug 12 during the installation process can be reduced.

[0186] In some embodiments, the outer surface 341 of the second protrusion abuts the inner surface of the casing 20 and is welded to the casing 20 to seal the opening 21 .

[0187] The outer surface 341 of the second protrusion is the surface of the second protrusion 34 facing the side wall 22 of the casing 20. The outer surface 341 of the second protrusion is a columnar surface, and optionally, the outer surface 341 of the second protrusion is a cylindrical surface.

[0188] The portion of the second protrusion 34 that extends into the casing 20 can form an interference fit, a middle fit, or a clearance fit with the casing 20. Optionally, the portion of the second protrusion 34 that extends into the casing 20 can form an interference fit with the casing 20, which can increase the connection strength between the casing 20 and the end cap 30 and improve the sealing performance.

[0189] Optionally, the second protrusion 34 and the side wall 22 of the casing 20 are connected by laser welding. During welding, a laser beam is applied to the boundary between the second protrusion 34 and the side wall 22, and the laser beam melts and connects at least a part of the outer surface 341 of the second protrusion to a part of the inner surface of the casing 20. The outer surface 341 of the second protrusion is abutted against the inner surface of the casing 20, which can reduce the risk of the laser beam entering the inside of the casing 20 and burning and damaging the electrode assembly 10.

[0190] Alternatively, the laser light may be directed onto the outer surface of the side wall 22 away from the second protrusion 34 .

[0191] In this embodiment, welding is used to achieve a tight seal, reduce the risk of electrolyte leakage, and increase the connection strength and flow capacity between the second protrusion 34 and the casing 20 .

[0192] The second recess 35 reduces the strength of the second protruding portion 34 and increases the elasticity of the second protruding portion 34, and during the welding process of the second protruding portion 34 and the casing 20, the second protruding portion 34 can release the welding stress by deformation, reduce the deformation and the risk of rupture of the welded area, and improve the sealing performance. In this embodiment, under the premise that the protruding degree of the second protruding portion 34 is guaranteed, the recessing degree of the second recess 35 is further guaranteed, the elasticity of the second protruding portion 34 is increased, and the second protruding portion 34 can release the welding stress by deformation.

[0193] In some embodiments, the cap body 31 is a flat plate structure, with the inner surface 31a of the cap body and the outer surface 31b of the cap body being parallel to each other.

[0194] 7 is a cross-sectional schematic view of a single battery provided according to some other embodiments of the present application. FIG. 8 is an enlarged schematic view of the circled frame B of the single battery shown in FIG.

[0195] 7 and 8, in some embodiments, the first protrusion 32 is provided around the outside of the cap body 31. In other words, the first protrusion 32 is a ring-shaped structure provided around the outside of the cap body 31.

[0196] In some embodiments, the portion of the first protrusion 32 that extends into the casing 20 can form an interference fit, a medium fit, or a clearance fit with the casing 20. Optionally, the portion of the first protrusion 32 that extends into the casing 20 can form an interference fit with the casing 20, which can increase the connection strength between the casing 20 and the end cap 30 and improve the sealing performance.

[0197] In some embodiments, the outer surface of the first projection 32 abuts the inner surface of the casing 20 and is welded to the casing 20 to seal the opening 21 .

[0198] In some other embodiments, the end cap 30 includes an extension 36 disposed around the outside of the first protrusion 32, with the surface of the extension 36 facing the first lug 12 abutting and welded around the end face of the opening 21 in the casing 20 to seal the opening 21.

[0199] The extension 36 has an inner surface and an outer surface opposed to each other along the thickness direction Z, and the inner surface of the extension 36 faces the first lug 12. Optionally, the extension 36 has an annular plate-like structure, and the inner surface of the extension 36 and the outer surface of the extension 36 are flat.

[0200] The extension 36 and the casing 20 are disposed along the thickness direction Z, and the inner surface of the extension 36 is parallel to the end surface of the casing 20 .

[0201] Optionally, during welding, a laser beam is irradiated onto the boundary between the end face of the casing 20 and the inner surface of the extension 36, and after welding, at least a portion of the inner surface of the extension 36 and at least a portion of the end face of the casing 20 are melted and connected.

[0202] In this embodiment, when the end cap 30 and the casing 20 are attached, the end face of the casing 20 acts as a limiting force in the thickness direction Z, thereby reducing the risk of the end cap 30 being tightly fitted into the casing 20 and improving the attachment efficiency.

[0203] The entire cap body 31 may be in the form of a flat plate, or a portion of it may protrude.

[0204] In some embodiments, the cap body 31 includes a main board body 313 and a third protruding portion 314, the main board body 313 is provided around the outside of the third protruding portion 314, the first protruding portion 32 is provided around the outside of the main board body 313, and the thin portion 311 is formed in the third protruding portion 314. The main board body 313 includes a first inner surface 313a and a first outer surface 313b provided opposite to each other, the first protruding portion 32 and the third protruding portion 314 protrude from the first inner surface 313a toward the electrode assembly 10 along a direction from the first inner surface 313a toward the electrode assembly 10, the top end surface of the first protruding portion 32 is closer to the first lug 12 than the top end surface of the third protruding portion 314, and a retraction gap G for retracting the thin portion 311 is formed between the current collecting member 50 and the third protruding portion 314.

[0205] The main board body 313 has a plate-like structure, and a first inner surface 313a and a first outer surface 313b are arranged opposite each other along the thickness direction Z. Optionally, the main board body 313 has a flat plate structure, and the first inner surface 313a and the first outer surface 313b are arranged parallel to each other in a plane.

[0206] Optionally, the top surface of the first protrusion 32 and the top surface of the third protrusion 314 are disposed in a plane parallel to each other.

[0207] The inner surface of the cap body includes the first inner surface 313a, a top end surface of the third protruding portion 314 and a side surface of the third protruding portion 314, and the side surface of the third protruding portion 314 is connected to the first inner surface 313a and the top end surface of the third protruding portion 314. At least a portion of the first protruding portion 32 protrudes from the top end surface of the third protruding portion 314 along a direction toward the electrode assembly 10.

[0208] During the normal circulation process of the battery unit 7, a small amount of gas may be released. The gas increases the internal pressure of the battery unit 7, posing a risk of deformation of the end cap 30. When the end cap 30 deforms, the weak part 311 is prone to creep. If the internal pressure of the battery unit 7 does not reach a threshold value, the weak part 311 may burst, causing the battery unit 7 to fail.

[0209] In this embodiment, the third protruding portion 314 is provided at the center of the end cap 30 to increase the strength of the end cap 30 and reduce deformation of the end cap 30. Since the third protruding portion 314 is in a protruding state and is not easily deformed, the provision of the weak portion 311 at the third protruding portion 314 reduces creep of the weak portion 311 and reduces the risk of failure of the weak portion 311.

[0210] In this embodiment, a retreat gap G is formed between the third protrusion 314 and the current collecting member 50, which reduces the risk of the current collecting member 50 clogging the exhaust passage when the weak portion 311 bursts, thereby achieving smooth exhaust and reducing safety risks.

[0211] In some embodiments, a third recessed portion 315 is formed at a position corresponding to the third protrusion 314 of the cap body 31, recessed along a direction from the first outer surface 313b toward the electrode assembly 10, and a weak portion 311 is formed in an area facing the bottom surface of the third recessed portion 315 of the third protrusion 314.

[0212] A weak portion 311 is provided in a portion of the third protruding portion 314 located between a bottom surface of the third recessed portion 315 and a top surface of the third protruding portion 314. Optionally, the bottom surface of the third recessed portion 315 and the top surface of the third protruding portion 314 are planar and parallel to each other.

[0213] The weak portion 311 is provided in an area facing the bottom surface of the third recessed portion 315 of the third protrusion 314, thereby increasing the distance between the weak portion 311 and other external members, thereby reducing the risk that the weak portion 311 will be crushed by the external members.

[0214] 9 is a cross-sectional schematic diagram of a battery unit provided according to another embodiment of the present application. FIG. 10 is an enlarged schematic diagram of a frame C of the battery unit shown in FIG.

[0215] As shown in Figures 9 and 10, in some embodiments, a first protrusion 32 is provided around the outside of the cap body 31, and a current collecting member 50 connects the cap body 31 and the first lug 12 to provide an electrical connection between the end cap 30 and the first lug 12.

[0216] In some embodiments, the current collecting member 50 includes a first current collecting portion 51 and a second current collecting portion 52 connected to the first current collecting portion 51, the first current collecting portion 51 is connected to the first lug 12 to electrically connect the current collecting member 50 to the first lug 12, and the second current collecting portion 52 is connected to the cap body 31 to electrically connect the current collecting member 50 to the end cap 30. The first current collecting portion 51 protrudes from the surface of the second current collecting portion 52 facing the electrode assembly 10, and a recessed recessed portion 53 is formed at a position corresponding to the first current collecting portion 51 of the current collecting member 50, recessed from the surface of the second current collecting portion 52 facing away from the electrode assembly 10 in a direction toward the electrode assembly 10, so that a recessed gap G is formed between the current collecting member 50 and the cap body 31.

[0217] In this embodiment, by providing an evacuation recess 53, an evacuation gap G is formed to prevent the first current collecting portion 51 from abutting against the cap body 31, thereby reducing the risk of the first current collecting portion 51 pressing against the weak portion 311 and improving safety.

[0218] The first current collecting portion 51 supports the central region of the first lug 12, and the first protrusion 32 supports the edge region of the first lug 12, thereby equalizing the force applied to the first lug 12 and reducing the risk of the lug of the electrode assembly 10 being offset or shifted in the thickness direction Z.

[0219] In some embodiments, the first current collecting portion 51 is abutted and welded to the first lug 12, and the second current collecting portion 52 is abutted and welded to the cap body 31.

[0220] The recess 53 reduces the thickness of the first current collecting portion 51, reduces the welding force required to weld the first current collecting portion 51 and the first lug 12, and reduces heat generation, thereby reducing the risk of burn damage to other components (e.g., the diaphragm).

[0221] In some embodiments, the second current collecting portion 52 is a flat plate structure disposed around the outside of the first current collecting portion 51 .

[0222] The entire cap body 31 may be in the form of a flat plate, or a portion of it may protrude.

[0223] In some embodiments, the cap body 31 includes a main board body 313 and a third protruding portion 314, the main board body 313 is provided around the outside of the third protruding portion 314, the first protruding portion 32 is provided around the outside of the main board body 313, and the thin portion 311 is formed in the third protruding portion 314. The main board body 313 has a first inner surface 313a and a first outer surface 313b provided opposite to each other, the first inner surface 313a faces the electrode assembly 10, the first protruding portion 32 and the third protruding portion 314 protrude along a direction from the first inner surface 313a toward the electrode assembly 10, the top surface of the first protruding portion 32 is closer to the first lug 12 than the top surface of the third protruding portion 314, and a retraction gap G for retracting the thin portion 311 is formed between the current collecting member 50 and the third protruding portion 314.

[0224] The recess 53 provides a protruding space for the third protruding portion 314 , and for example, at least a portion of the third protruding portion 314 extends into the recess 53 .

[0225] In some embodiments, the first protrusion 32 abuts and is welded to the first lug 12 to provide an electrical connection between the end cap 30 and the first lug 12 .

[0226] In this embodiment, the end cap 30 is directly electrically connected to the first lug 12 via the first protrusion 32, simplifying the structure of the battery unit 7 and, for example, enabling the current collecting member 50 to be omitted.

[0227] FIG. 11 is a schematic flow chart of a method for manufacturing a battery unit provided according to some embodiments of the present application.

[0228] As shown in FIG. 11, the method for manufacturing a single battery according to the embodiment of the present application includes the following steps:

[0229] S100, providing a casing having an opening;

[0230] S200, preparing an electrode assembly, mounting the electrode assembly in a casing, and providing a first lug on one end of the electrode assembly toward the opening;

[0231] S300, preparing an end cap including a cap body having a weakened portion and a first protrusion connected to the cap body;

[0232] S400, connecting the end cap to the casing to cover the opening with the end cap;

[0233] Here, the end cap is configured such that when the internal pressure of the battery unit reaches a threshold value, the weak portion ruptures to release the internal pressure, and the first protrusion protrudes from the cap body along a direction facing the electrode assembly, supports the first lug, and forms an evacuation gap between the first lug and the cap body for the weak portion to retreat.

[0234] For the relevant structure of the battery unit manufactured by the above-mentioned manufacturing method for the battery unit, reference may be made to the description of the battery unit in each of the above-mentioned embodiments.

[0235] When assembling a battery unit based on the above-mentioned manufacturing method for a battery unit, it is not necessary to perform the above steps in sequence, that is, the steps may be performed in the order of the embodiment, or in an order different from that of the embodiment, or multiple steps may be performed simultaneously. For example, steps S100 and S300 may be performed in any order, or may be performed simultaneously.

[0236] FIG. 12 is a schematic block diagram of a system for manufacturing a single battery provided according to some embodiments of the present application.

[0237] As shown in FIG. 12 , an embodiment of the present application further provides a system 90 for manufacturing a single battery, the system 90 comprising:

[0238] a first preparation device 91 for preparing a casing having an opening;

[0239] a second preparation device 92 for preparing the electrode assembly, mounting the electrode assembly within the casing, and providing a first lug on one end of the electrode assembly facing the opening;

[0240] a third preparation device 93 for preparing an end cap including a cap body to be provided with a weakened portion and a first protrusion connected to the cap body;

[0241] an assembly device 94 for connecting the end cap to the casing and covering the opening with the end cap;

[0242] Here, the end cap is configured such that when the internal pressure of the battery unit reaches a threshold value, the weak portion ruptures to release the internal pressure, and the first protrusion protrudes from the cap body along a direction facing the electrode assembly, supports the first lug, and forms an evacuation gap between the first lug and the cap body for the weak portion to retreat.

[0243] For the relevant structure of the battery unit manufactured by the above manufacturing system, please refer to the description of the battery unit in each of the above embodiments.

[0244] It should be noted that, unless inconsistent, the embodiments and features of the embodiments in this application can be combined with each other.

[0245] Finally, the above embodiments are for illustrating the technical means of the present application, and are not intended to be limiting. Although the present application has been described in detail with reference to the above embodiments, those skilled in the art may still modify the technical means described in each of the above embodiments or equivalently replace some technical features, and such modifications or replacements do not cause the essence of the corresponding technical means to deviate from the spirit and scope of the technical means of each of the embodiments of the present application.

Claims

1. a casing having an opening; an electrode assembly housed within the casing and having a first lug on one end facing the opening; an end cap covering the opening, the end cap including a cap body and a first protrusion connected to the cap body, the cap body being provided with a weakened portion, the end cap being configured to burst along the weakened portion to release the internal pressure when the internal pressure of the battery unit reaches a threshold value; wherein the first protrusion protrudes from the cap body toward a direction facing the electrode assembly to support the first lug, and a retraction gap for retracting the thin portion is formed between the first lug and the cap body; the end cap electrically connects the first lug and the casing; the casing includes a side wall and a bottom wall connected to the side wall, the side wall extends along a thickness direction of the end cap and is disposed around an outer periphery of the electrode assembly, and an electrode extraction hole is provided in the bottom wall; The electrode assembly further includes a second lug, the first lug and the second lug having opposite polarities and located at opposite ends of the electrode assembly, respectively; the battery unit includes an electrode terminal attached to the electrode lead-out hole, the electrode terminal being electrically connected to the second lug; The bottom wall and the side wall are integrally formed.

2. 2. The battery unit described in claim 1, wherein a first recess portion is formed in the end cap at a position corresponding to the first protrusion portion, the first recess portion being recessed along a direction facing the electrode assembly from an outer surface of the cap body, and a bottom surface of the first recess portion is closer to the first lug than an inner surface of the cap body.

3. The battery unit according to claim 1 or 2, wherein the first protrusion is abutted against and welded to the first lug, thereby achieving electrical connection between the end cap and the first lug.

4. a current collecting member disposed between the end cap and the first lug; the current collecting member is used to connect the end cap and the first lug to realize an electrical connection between the end cap and the first lug; The battery unit according to claim 1 , wherein the retraction gap is located between the current collecting member and the cap body in a thickness direction of the end cap.

5. The battery unit according to claim 4 , wherein the current collecting member covers the thin portion along a thickness direction of the end cap to separate the thin portion from the first lug.

6. The battery unit according to claim 4 or 5, wherein the first protrusion is provided around the outside of the cap body, and the current collecting member is used to connect the cap body and the first lug to realize an electrical connection between the end cap and the first lug.

7. the current collecting member includes a first current collecting portion and a second current collecting portion connected to the first current collecting portion, the first current collecting portion is connected to the first lug to electrically connect the current collecting member and the first lug, and the second current collecting portion is connected to the cap body to electrically connect the current collecting member and the end cap, 7. The battery unit described in claim 6, wherein the first current collecting portion protrudes from a surface of the second current collecting portion facing the electrode assembly, and a recessed recess is formed at a position of the current collecting member corresponding to the first current collecting portion, the recessed recess being recessed from a surface of the second current collecting portion facing away from the electrode assembly in a direction facing the electrode assembly, and the recessed gap is formed between the current collecting member and the cap body.

8. The battery unit according to claim 7 , wherein the first current collecting portion is abutted against and welded to the first lug, and the second current collecting portion is abutted against and welded to the cap body.

9. At least a portion of the current collecting member is located between the first protrusion and the first lug; The battery unit according to claim 4 , wherein the first protrusion supports the first lug via the current collecting member.

10. The battery unit according to claim 9 , wherein a portion of the current collecting member is abutted against and welded to the first lug, and another portion of the current collecting member is abutted against and welded to the first protrusion.

11. The battery unit according to claim 10 , wherein the current collecting member has a flat plate structure.

12. The battery unit according to any one of claims 9 to 11, wherein the first protrusion is provided around an outer periphery of the cap body.

13. The battery unit according to any one of claims 9 to 11, wherein the cap body is provided around an outer periphery of the first protrusion.

14. The end cap further includes a second protrusion disposed around an exterior of the cap body; 14. The battery unit according to claim 13, wherein the second protrusion protrudes from an inner surface of the cap body in a direction facing the electrode assembly, a top end surface of the second protrusion is closer to the first lug than a top end surface of the first protrusion, and the second protrusion abuts against the first lug to support the first lug.

15. 15. The battery unit described in claim 14, wherein a second recess portion is formed at a position on the end cap corresponding to the second protrusion portion, the second recess portion being recessed along a direction facing the electrode assembly from the outer surface of the cap body, and a bottom surface of the second recess portion is closer to the first lug than an inner surface of the cap body.

16. The battery unit according to any one of claims 13 to 15, wherein an outer surface of the second protrusion is abutted against an inner surface of the casing and welded to the casing to seal the opening.

17. The battery unit according to any one of claims 6 to 16, wherein the cap body has a flat plate structure.

18. the cap body includes a main board body and a third protrusion, the main board body is provided around an outer periphery of the third protrusion, the first protrusion is provided around an outer periphery of the main board body, and the weak portion is formed on the third protrusion; The main board body has a first inner surface and a first outer surface arranged opposite to each other, the first inner surface faces the electrode assembly, the first protrusion and the third protrusion protrude from the first inner surface along a direction facing the electrode assembly, a top end surface of the first protrusion is closer to the first lug than a top end surface of the third protrusion, and the evacuation gap for evacuating the weak portion is formed between the collecting member and the third protrusion.

19. The battery unit described in claim 18, wherein a third recess portion recessed along a direction facing the electrode assembly from the first outer surface is formed at a position corresponding to the third protrusion portion in the cap body, and the weak portion is formed in an area of ​​the third protrusion corresponding to a bottom surface of the third recess portion.

20. The battery unit according to any one of claims 1 to 19, wherein a groove is provided in the cap body, and the weak portion is formed in an area of ​​the cap body facing the groove.

21. 2. The battery unit according to claim 1, wherein the first lug is a negative lug and the base material of the casing is steel.

22. The battery unit according to any one of claims 1 to 21, wherein the base material of the casing is the same as the base material of the end caps.

23. The battery unit according to any one of claims 1 to 22, wherein the battery unit is a cylindrical battery unit.

24. A battery comprising a plurality of the battery units according to any one of claims 1 to 23.

25. 25. A power using device comprising the battery of claim 24 for providing electrical power energy.

26. Providing a casing having an opening; providing an electrode assembly, mounting the electrode assembly within the casing and providing a first lug on an end of the electrode assembly facing the opening; providing an end cap including a cap body having a weakened portion and a first protrusion connected to the cap body; and connecting the end cap to the casing to cover the opening with the end cap; wherein the end cap is configured such that, when an internal pressure of the battery unit reaches a threshold value, the weak portion ruptures to release the internal pressure, and the first protrusion protrudes from the cap body along a direction facing the electrode assembly and supports the first lug, forming an evacuation gap between the first lug and the cap body for evacuating the weak portion; the end cap electrically connects the first lug and the casing; the casing includes a side wall and a bottom wall connected to the side wall, the side wall extends along a thickness direction of the end cap and is disposed around an outer periphery of the electrode assembly, and an electrode extraction hole is provided in the bottom wall; The electrode assembly further includes a second lug, the first lug and the second lug having opposite polarities and located at opposite ends of the electrode assembly, respectively; the battery unit includes an electrode terminal attached to the electrode lead-out hole, the electrode terminal being electrically connected to the second lug; The bottom wall and the side wall are integrally formed.

27. a first preparation device for preparing a casing having an opening; a second preparation device for preparing an electrode assembly, mounting the electrode assembly within the casing, and providing a first lug on an end of the electrode assembly facing the opening; a third preparation device for preparing an end cap including a cap body having a weakened portion and a first protrusion connected to the cap body; an assembly device for connecting the end cap to the casing and covering the opening with the end cap; wherein the end cap is configured such that, when an internal pressure of the battery unit reaches a threshold value, the weak portion ruptures to release the internal pressure, and the first protrusion protrudes from the cap body along a direction facing the electrode assembly and supports the first lug, forming an evacuation gap between the first lug and the cap body for evacuating the weak portion; the end cap electrically connects the first lug and the casing; the casing includes a side wall and a bottom wall connected to the side wall, the side wall extends along a thickness direction of the end cap and is disposed around an outer periphery of the electrode assembly, and an electrode extraction hole is provided in the bottom wall; The electrode assembly further includes a second lug, the first lug and the second lug having opposite polarities and located at opposite ends of the electrode assembly, respectively; the battery unit includes an electrode terminal attached to the electrode lead-out hole, the electrode terminal being electrically connected to the second lug; The bottom wall and the side wall are integrally formed.

Images