Patent Description:
Lithium batteries are widely used due to advantages such as a small size, a high energy density, a high power density, reusability for many cycles, and a long shelf life. However, when a battery is in abnormal use, for example, when the battery is overcharged or when an abnormal short circuit occurs inside the battery, an internal temperature and pressure is prone to rise, and a housing of the battery is at a risk of cracking or even explosion due to inability to withstand the internal pressure.

To avoid explosion of a conventional battery, a pressure relief region is usually disposed at an end cap of a battery cell. However, in such a practice, a battery in use is usually in the form of a battery module formed by connecting a plurality of battery cells in series, parallel, or series-and-parallel pattern. Therefore, when an internal pressure or temperature of the housing of the battery cell reaches a threshold, the internal pressure released by the battery cell in the pressure relief region is prone to impact another battery cell that is adjacent. The impact is prone to break the other battery cell or even cause a secondary explosion accident, thereby reducing safety and reliability of the battery in use. <CIT> relates to a modular cooling system for electronics, particularly focusing on improving the heat dissipation in electronic devices through a layered structure of cooling fins and radiators.

<CIT> describes a power supply circuit designed to improve efficiency by reducing loss in the converter. It incorporates a switching element to optimize the power transfer between components.

<CIT> introduces a liquid crystal display (LCD) backlight system that enhances brightness and uniformity. It focuses on improving the light diffusion through a specialized optical structure.

<CIT> focuses on an adjustable desk lamp with a rotatable base and arms, providing flexible lighting options with enhanced stability and durability.

This application discloses a battery, an electrical device, and a method and device for manufacturing a battery to improve safety of the battery. The claimed subject-matter is described by independent claims <NUM> and <NUM>. Preferred embodiments are defined by the dependent claims <NUM> through <NUM>.

According to a first aspect of this application, a battery is provided, including: a plurality of battery cells arranged along a first direction. Each battery cell includes an end cap and a housing, an opening is made at an end of the housing along the first direction, the end cap is configured to close the opening, and the housing includes a first wall extending along the first direction. A pressure relief region is provided on the first wall. The pressure relief region is configured to release pressure along a second direction when an internal pressure or temperature of the battery cell reaches a threshold. The second direction intersects the first direction.

In the battery according to embodiments of this application, a plurality of battery cells are arranged along the first direction. The end cap is mounted at the end of the housing along the first direction. The pressure relief region is provided on the first wall of the housing, the first wall extending along the first direction. The battery cell releases the internal pressure in the pressure relief region when the internal pressure or temperature in the housing of the battery cell reaches the threshold. The internal pressure can be released outward along the second direction intersecting the first direction. In this way, the pressure released from the pressure relief region will not impact an adjacent battery cell or damage other battery cells, thereby improving the safety of the battery.

According to the invention, the pressure relief region of the first wall includes a fragile portion. The pressure relief region is configured to break the fragile portion to release the pressure when the internal pressure or temperature of the battery cell reaches the threshold.

According to the invention, the fragile portion is formed on the first wall by making a first groove in the pressure relief region. A thickness of the fragile portion is less than a thickness of a remaining part of the first wall.

In this structure in which the fragile portion is formed by making the first groove in the pressure relief region, the first groove can be formed in the pressure relief region of the first wall by stamping, milling, laser engraving, and other processing methods. The structure is simple, and the processing is convenient, thereby helping to reduce the manufacturing cost.

In some embodiments, the first groove is made on an outer surface of the housing, and/or the first groove is made on an inner surface of the housing.

Due to the limited space inside the housing of the battery cell, by making the first groove on the outer surface of the first wall, it is convenient to process and form the first groove, and the processing is facilitated. By making the first groove on the inner surface of the first wall, the first groove is prevented from being exposed outside the housing, thereby improving visual appearance of the battery cell. By making the first groove on both the inner surface and the outer surface of the first wall, a problem is solved that the existing processing method can hardly achieve a preset processing depth of the first groove when the first groove is made on only the inner surface or only the outer surface of the first wall.

In some embodiments, the battery cell is a cylindrical structure, and a bottom side of the first groove is a curved face, or a bottom side of the first groove is a flat face.

For a battery cell with a cylindrical structure, when the bottom side of the first groove is a curved face parallel to the inner surface and/or the outer surface of the first wall, the thickness of the fragile portion is equalized at all positions, and the structural strength of the fragile portion is relatively consistent. When the internal pressure or temperature of the battery cell reaches the threshold, the internal pressure can be evenly released from all positions of the fragile portion. When the bottom side of the first groove is a flat face, the structure is conveniently processible, and the thickness of the fragile portion gradually decreases from flanks to center in the width direction. When the battery cell is blasted, the fragile portion is ruptured at a thinnest position. The structural strength of the fragile portion is relatively high, and the fragile portion is not prone to rupture under an external force other than the internal pressure or temperature. In some embodiments, a second groove is made at a bottom side of the first groove. The thickness of the fragile portion at the second groove is less than the thickness of the remaining part of the fragile portion. The pressure relief region is configured to break a bottom side of the second groove to release the pressure when the internal pressure or temperature of the battery cell reaches the threshold.

By making a first groove in the pressure relief region first and then making a second groove on the bottom side of the first groove, with the first groove and the second groove being deepened gradually in the pressure relief region, the problem of being difficult to achieve the preset processing depth of the second groove in existing processing technology is solved, and the processing is facilitated. In addition, the thickness of the fragile portion at the second groove is less than the thickness of the remaining part of the fragile portion. Therefore, the structural strength of the fragile portion is high, and the battery cell is blasted at the bottom side of the second groove, thereby achieving an effect of directional blasting.

In some embodiments, the first wall includes a through-hole extending along the second direction and a pressure relief sheet covering the through-hole. The fragile portion is disposed on the pressure relief sheet.

In this way, the fragile portion may be processed and formed on the pressure relief sheet first, and then mounted on the first wall through the pressure relief sheet. The structural processing and design of the fragile portion are not prone to be affected by the shape of the housing of the battery cell, thereby helping to reduce the difficulty of processing and manufacturing the fragile portion.

In some embodiments, the first wall further includes a body portion, and the body portion and the fragile portion are integrally formed.

In some embodiments, the first groove extends along the first direction. A ratio of a dimension of the first groove in the first direction to a dimension of the first wall in the first direction is greater than <NUM>/<NUM>.

The gas inside the battery cell generally concentrates at a position close to two ends along the first direction. If the ratio of the dimension of the first groove in the first direction to the dimension of the first wall in the first direction is greater, the fragile portion formed by making the first groove in the pressure relief region is closer to positions at the two ends of the battery cell along the first direction. This effectively shortens a pressure relief path of the gas inside the battery cell, so that the battery cell can release pressure quickly in time when the internal temperature or pressure of the battery cell reaches the threshold.

In some embodiments, the first groove is an annular structure.

With the first groove made in an annular shape, when the internal pressure or temperature of the battery cell reaches the threshold, the area of releasing pressure outward from the battery cell is increased, so that the internal pressure of the battery cell can be released quickly to avoid violent explosion, thereby improving the safety of the battery cell.

In some embodiments, the first groove is disposed around a central axis of the battery cell, the central axis being parallel to the first direction.

In other words, the fragile portion is disposed as a circle around the central axis of the battery cell, the central axis being parallel to the first direction. When the fragile portion is broken, the battery cell can release pressure outward from all positions surrounded by the fragile portion, thereby helping to shorten the path of gas exhausting and pressure release and improve the pressure release efficiency.

In some embodiments, the first groove includes a first part and a second part that are in communication with each other. The fragile portion includes a first fragile portion formed by disposing the first part and a second fragile portion formed by disposing the second part. A thickness of the first fragile portion is less than a thickness of the second fragile portion. The pressure relief region is configured to break the first fragile portion and avoid breaking at least a part of the second fragile portion when the internal pressure or temperature of the battery cell reaches the threshold.

In this way, when the internal pressure of the battery cell reaches the threshold, the first fragile portion is broken, but at least a part of the second fragile portion remains unbroken, thereby avoiding flying debris generated by the housing when the fragile portion is completely broken, and ensuring the safety of the battery cell.

In some embodiments, the first wall includes two fragile portions spaced apart along the first direction in the pressure relief region.

By disposing two fragile portions, when the internal pressure or temperature of the battery cell reaches the threshold, the area of releasing pressure is increased in the pressure relief region, the pressure relief capability of the battery cell is improved, and the safety of the battery is further improved.

In some embodiments, a spacing between two fragile portions along the first direction is set based on a capacity of the battery cell.

In some embodiments, the housing further includes a second wall. The second wall and the end cap are connected to two ends of the first wall respectively, the two ends being opposite to each other along the first direction. The battery cell further includes an electrode assembly. After being wound, the electrode assembly includes a first end face contiguous to the end cap and a second end face contiguous to the second wall in the first direction.

In some embodiments, at least a part of the pressure relief region is a region located between the first end face and the end cap along the first direction on the first wall.

Generally, the gas inside the battery cell is prone to concentrate at the two ends of the electrode assembly. Therefore, by disposing at least a part of the pressure relief region in the area that is on the first wall and between the first end face of the electrode assembly and the end cap, such embodiments can reduce the paths for releasing outward the pressure that is generated by the gas located between the end cap and the electrode terminal.

In some embodiments, at least a part of the pressure relief region is a region located between the second end face and the second wall along the first direction on the first wall.

Generally, the gas inside the battery cell is prone to concentrate at the two ends of the electrode assembly. Therefore, by disposing at least a part of the pressure relief region in the area that is on the first wall and between the second end face of the electrode assembly and the second wall, such embodiments can reduce the paths for releasing outward the pressure that is generated by the gas located between the second wall and the second end face of the electrode terminal.

According to a second aspect of this application, an electrical device is provided, including the battery described above. The battery is configured to provide electrical energy.

According to a third aspect of this application, a method for manufacturing a battery is provided, including: providing a plurality of battery cells, where each battery cell includes an end cap and a housing, an opening is made at an end of the housing along a first direction, the end cap is configured to close the opening, the housing includes a first wall extending along the first direction, a pressure relief region is provided on the first wall, the pressure relief region is configured to release pressure along a second direction when an internal pressure or temperature of the battery cell reaches a threshold, and the second direction intersects the first direction; and arranging the plurality of battery cells along the first direction.

In this method, a plurality of battery cells are arranged along the first direction. The end cap is mounted at the end of the housing along the first direction. The pressure relief region is provided on the first wall of the housing, the first wall extending along the first direction. The battery cell releases the internal pressure in the pressure relief region when the internal pressure or temperature in the housing of the battery cell reaches the threshold. The internal pressure can be released outward along the second direction intersecting the first direction. In this way, the pressure released from the pressure relief region will not impact an adjacent battery cell or damage other battery cells, thereby improving the safety of the battery.

According to a fourth aspect of this application, a device for manufacturing a battery is provided, including: a battery cell manufacturing module, configured to manufacture battery cells, where each battery cell includes: an end cap and a housing, an opening is made at an end of the housing along a first direction, the end cap is configured to close the opening, the housing includes a first wall extending along the first direction, a pressure relief region is provided on the first wall, the pressure relief region is configured to release pressure along a second direction when an internal pressure or temperature of the battery cell reaches a threshold, and the second direction intersects the first direction; and an assembling module, configured to arrange a plurality of battery cells along the first direction.

The drawings described herein are intended to enable a further understanding of this application, and constitute a part of this application. The exemplary embodiments of this application and the description thereof are intended to explain this application but not to constitute any undue limitation on this application. In the drawings:.

To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the following gives a clear and thorough description of the technical solutions in the embodiments of this application with reference to the drawings in the embodiments of this application. Apparently, the described embodiments are merely a part of but not all of the embodiments of this application. All other embodiments derived by a person of ordinary skill in the art based on the embodiments of this application without making any creative efforts fall within the protection scope of the appended claims.

Unless otherwise defined, all technical and scientific terms used herein have the same meanings as usually understood by a person skilled in the technical field of this application. The terms used in the specification of this application are merely intended for describing specific embodiments but are not intended to limit this application. The terms "include" and "contain" and any variations thereof used in the specification, claims, and brief description of drawings of this application are intended as non-exclusive inclusion. The terms such as "first" and "second" used in the specification, claims, and brief description of drawings herein are intended to distinguish between different items, but are not intended to describe a specific sequence or order of precedence.

Reference to "embodiment" herein means that a specific feature, structure or characteristic described with reference to the embodiment may be included in at least one embodiment of this application. Reference to this term in different places in the specification does not necessarily represent the same embodiment, nor does it represent an independent or alternative embodiment in a mutually exclusive relationship with other embodiments. A person skilled in the art explicitly and implicitly understands that the embodiments described herein may be combined with other embodiments.

The term "and/or" herein merely indicates a relationship between related items, and represents three possible relationships. For example, "A and/or B" may represent the following three circumstances: A alone, both A and B, and B alone. In addition, the character "/" herein generally indicates an "or" relationship between the item preceding the character and the item following the character.

"A plurality of" referred to in this application means two or more (including two). Similarly, "a plurality of groups" means two or more groups (including two groups), and "a plurality of pieces" means two or more pieces (including two pieces).

A battery cell and a battery including a plurality of battery cells according to embodiments of this application are applicable to various devices that use a battery as a power supply, for example, a mobile phone, a portable device, a notebook computer, an electric power cart, an electric vehicle, a ship, a spacecraft, an electric toy, an electric tool. The spacecraft may include an airplane, a rocket, a space shuttle, a spaceship, and the like. The electric toy may include a fixed or mobile electric toy, such as a game console, an electric car toy, an electric ship toy, an electric airplane toy, and the like. The electric tool may include an electric tool for metal cutting, an electric grinding tool, an electric assembly tool, an electric tool for railways, such as an electric drill, an electric grinder, an electric wrench, an electric screwdriver, an electric hammer, an electric impact drill, a concrete vibrator, an electric planer, and the like.

The battery cell and the battery including a plurality of battery cells according to embodiments of this application are not only applicable to the devices described above, but also applicable to all battery-powered devices. However, for brevity, the following embodiments are described by using a vehicle <NUM> as an example.

Referring to <FIG> is a schematic structural diagram of a vehicle <NUM> according to an embodiment of this application. The vehicle <NUM> may be an oil-fueled vehicle, a natural gas vehicle, or a new energy vehicle. The new energy vehicle may be a battery electric vehicle, a hybrid electric vehicle, a range-extended electric vehicle, or the like. A battery <NUM> may be disposed inside the vehicle <NUM>. The battery <NUM> may be a battery pack or a battery module. For example, the battery <NUM> may be disposed at the bottom, front, or rear of the vehicle <NUM>. The controller <NUM> and the motor <NUM> may be further disposed inside the vehicle <NUM>. The controller <NUM> may be configured to control the battery <NUM> to supply power to the motor <NUM>. Through a transmission mechanism, the motor <NUM> may drive wheels of the vehicle <NUM> to run. The battery <NUM> may be configured to supply power to the vehicle <NUM>. For example, the battery <NUM> may serve as an operating power supply of the vehicle <NUM> to power a circuit system of the vehicle <NUM>. Alternatively, the battery may be configured to meet operating power usage requirements of the vehicle <NUM> that is being started or navigated or running. In another embodiment of this application, the battery <NUM> serves not only as an operating power supply of the vehicle <NUM>, but may also serve as a drive power supply of the vehicle <NUM> to provide driving motive power for the vehicle <NUM> in place of or partially in place of oil or natural gas.

Referring to <FIG> is a schematic structural exploded view of a battery <NUM> according to an embodiment of this application. To meet different power usage requirements, the battery <NUM> may include one or more battery cells <NUM>. The plurality of battery cells <NUM> may be connected in series, parallel, or series-and-parallel pattern. The series-and-parallel pattern means a combination of series connection and parallel connection. Alternatively, the plurality of battery cells <NUM> may be connected in series, parallel, or series-and-parallel pattern to form a battery module (or referred to as a battery group) first, and then a plurality of battery modules may be connected in series, parallel, or series-and-parallel pattern to form the battery <NUM>. In other words, the battery <NUM> may be directly formed of a plurality of battery cells <NUM>, or the battery cells may form a battery module first and then a plurality of battery modules form the battery <NUM>.

In the embodiment shown in <FIG>, the battery <NUM> includes a plurality of battery cells <NUM>. The battery <NUM> further includes a box. The interior of the box is a hollow structure. A plurality of battery cells <NUM> are accommodated in the box. The box may further include a first cover portion <NUM> and a second cover portion <NUM>. The first cover portion <NUM> and the second cover portion <NUM> are snap-fitted together. The plurality of battery cells <NUM> are connected in series, parallel, or series-and-parallel pattern, and then placed in an accommodation space formed by snap-fitting the first cover portion <NUM> and the second cover portion <NUM>. The plurality of battery cells <NUM> may be placed in the box horizontally or vertically. As an example in this application, a plurality of battery cells <NUM> are placed in the box horizontally.

Optionally, referring to <FIG> is a schematic diagram of a connection structure between one battery cell <NUM> and another battery cell <NUM> in a battery <NUM> according to an embodiment of this application. The battery <NUM> may further include other structures. For example, the battery <NUM> may further include a busbar component <NUM> configured to implement electrical connection between the plurality of battery cells <NUM>.

The battery cell <NUM> may be in a cylindrical shape, a flat shape, a cuboidal shape, or other shapes. As an example in this application, the battery cell <NUM> is a cylinder.

As shown in <FIG> is a schematic structural exploded view of an existing battery cell <NUM>. An electrode assembly <NUM> and an electrolytic solution are disposed in the battery cell <NUM>. The electrode assembly <NUM> may be formed by stacking or winding a positive electrode plate, a negative electrode plate, and a separator together. The battery cell <NUM> works primarily by the movement of metal ions in the electrolytic solution between the positive electrode plate and the negative electrode plate. The separator is an insulator located between the positive electrode plate and the negative electrode plate. The positive electrode plate and the negative electrode plate each include a coated region and an uncoated region. A positive active material is coated on the coated region of the positive electrode plate, and a negative active material is coated on the coated region of the negative electrode plate. The active materials are coated on a current collector formed of a metal sheet. No active material is coated on the uncoated region. To be specific, the positive electrode plate includes a positive current collector and a positive active material layer. The positive active material layer is coated on a surface of the positive current collector. A part that is of the current collector and that is not coated with the positive active material layer protrudes from a part that is of the current collector and that is coated with the positive active material layer. The part that is of the current collector and that is not coated with the positive active material layer serves as a positive tab. The negative electrode plate includes a negative current collector and a negative active material layer. The negative active material layer is coated on a surface of the negative current collector. A part that is of the current collector and that is not coated with the negative active material layer protrudes from a part that is of the current collector and that is coated with the negative active material layer. The part that is of the current collector and that is not coated with the negative active material layer serves as a negative tab.

The battery cell <NUM> further includes an end cap <NUM> and a housing <NUM>. An opening is made on the housing <NUM>. An inner space in communication with the opening is provided in the housing <NUM>. The inner space may be configured to accommodate the electrode assembly <NUM> and the electrolytic solution. The end cap <NUM> fits onto the opening of the housing <NUM> to seal the electrode assembly <NUM> and the electrolytic solution in the housing <NUM>. An electrode terminal is disposed on the end cap <NUM>. The electrode terminal is electrically connected to a positive tab or a negative tab in the electrode assembly <NUM> by a connector adapter.

Still referring to <FIG>, in order to improve safety of the battery <NUM>, a pressure relief position <NUM> is usually disposed on the battery cell <NUM>. The pressure relief position <NUM> is a pressure relief region actuated to relieve the internal pressure or temperature when the internal pressure or temperature of the battery cell <NUM> reaches a preset threshold, and is also referred to as a pressure relief region. The pressure relief region may be in the form of an explosion-proof valve, a gas valve, a pressure relief valve, a safety valve, or the like, and may specifically adopt a pressure-sensitive or temperature-sensitive element or structure. To be specific, when the internal pressure or temperature of the battery cell <NUM> reaches the preset threshold, the pressure relief region is actuated or a fragile structure disposed in the pressure relief region is broken to form an opening or channel for relieving the internal pressure or temperature.

Currently, the pressure relief region of the battery cell <NUM> is usually disposed on the end cap <NUM>. That is, both the pressure relief region and the electrode terminal are located on the end cap <NUM>. For a battery <NUM> in use, a plurality of battery cells <NUM> are usually connected in series, parallel, or series-and-parallel pattern to form a battery module, and one battery cell <NUM> is usually connected to another battery cell <NUM> in an end-to-end opposition way. The pressure relief region is ruptured when thermal runaway occurs due to overcharge or abnormal short circuit inside the battery cell <NUM>. During the release of the internal pressure of the battery cell <NUM>, another battery cell <NUM> that is adjacent is prone to be impacted. The impact causes the other battery cell <NUM> to break, or even results in a secondary explosion accident, thereby reducing the safety and reliability of the battery <NUM> in use.

To solve the foregoing problem and improve the safety of the battery cell <NUM>, this application optimizes the structure and position of the pressure relief region.

In some embodiments, referring to <FIG>, <FIG>, and <FIG> is a schematic structural diagram of a battery cell <NUM> according to some embodiments of this application. The battery <NUM> includes a plurality of battery cells <NUM>. The plurality of battery cells <NUM> are arranged along the first direction. Each battery cell <NUM> includes an end cap <NUM> and a housing <NUM>. An opening is made at the end of the housing <NUM> along the first direction. The end cap <NUM> is configured to seal the opening. The housing <NUM> includes a first wall extending in the first direction. A pressure relief region is provided on the first wall. The pressure relief region is configured to release pressure along a second direction when the internal pressure or temperature of the battery cell <NUM> reaches the threshold. The second direction intersects the first direction.

As an example, the battery cell <NUM> may be a cylindrical structure, a cuboidal structure, or other structures. That is, the housing <NUM> of the battery cell <NUM> may be a cylindrical structure, or a cuboidal structure, or other structures.

The first direction may be a length direction of the battery cell <NUM> (the X-axis direction in the drawing).

Understandably, the number of openings of the housing <NUM> may be one or two. As an example, the opening is made at both ends of the housing <NUM> along the length direction separately. The number of the end caps <NUM> is also two. One of the two end caps <NUM> fits onto the opening at one end of the housing <NUM>. The other fits onto the opening at the other end of the housing <NUM>. In other embodiments, alternatively, the opening is made at one of two ends of the housing <NUM> along the length direction, but not made at the other end. The end cap <NUM> fits onto the opened end of the housing <NUM>.

As an example, for a cylinder-structured battery cell <NUM>, the first wall may be a cylindrical surface of the cylindrical housing <NUM>. For a cuboid-structured battery cell <NUM>, the first wall may be at least one of four sidewalls of the cuboidal housing <NUM>. Understandably, the first wall may be parallel to the first direction, or may be at a preset angle to the first direction. Preferably, the first wall is parallel to the first direction. As an example, that the first direction intersects the second direction may be that the first direction is perpendicular to the second direction. Alternatively, the first direction may be at a preset angle such as <NUM>° to the second direction, without being specifically limited herein. For another example, for a cylinder-structured battery cell <NUM>, the second direction may be a radial direction of the battery cell <NUM>.

In the battery <NUM> according to this embodiment of this application, a plurality of battery cells <NUM> are arranged along the first direction. The end cap <NUM> is mounted at the end of the housing <NUM> along the first direction. The pressure relief region is provided on the first wall of the housing <NUM>, the first wall being parallel to the first direction. When the internal pressure and temperature of the battery cell <NUM> reach the threshold due to overcharge or an abnormal short circuit inside the battery cell <NUM>, the internal pressure can be released outward along the second direction that intersects the first direction. In this way, the arrangement direction of the battery cells <NUM> is different from the pressure release direction of the battery cells <NUM>. Therefore, the pressure released from the pressure relief region will not cause impact or even damage to other adjacent battery cells <NUM>, thereby improving the safety of the battery <NUM> in use. In addition, conductive materials splattered from the pressure relief region are not likely to be splattered onto the busbar component <NUM> of the adjacent battery <NUM>, where the busbar component is independently located between the ends and is configured to electrically connect the battery cells <NUM>. This can effectively prevent a second accident caused by a short circuit between the battery cells <NUM> arising from the conductive materials.

In some optional embodiments, the first wall includes a fragile portion <NUM> in the pressure relief region. When the internal pressure or temperature on the pressure relief portion inside the battery cell <NUM> reaches the threshold, the fragile portion <NUM> is broken to release the internal pressure of the battery cell <NUM>.

Understandably, in other embodiments, the fragile portion <NUM> may be formed on the first wall by applying a material in the pressure relief region with a structural strength lower than the structural strength of the body portion of the first wall; or, the fragile portion <NUM> may be formed by disposing a pressure relief component or a pressure relief mechanism in the pressure relief region, or the like, as long as the internal pressure of the battery cell <NUM> can be released when the internal temperature or pressure of the battery cell <NUM> reaches the threshold.

Referring to <FIG> are schematic structural sectional views of a housing <NUM> sectioned along an A-A direction according to some embodiments of this application. The fragile portion <NUM> is formed on the first wall by making a first groove <NUM> in the pressure relief region. A thickness h1 of the fragile portion <NUM> is less than a thickness h0 of a remaining part of the first wall.

The first groove <NUM> may be a groove of various shapes, such as a linear shape, an X shape, an annular shape, without being limited to the examples. As shown in <FIG>, the first groove <NUM> shown in <FIG> is a linear structure.

By making the first groove <NUM> in the pressure relief region in such a way that the thickness h1 at the position of the first groove <NUM> is less than the thickness h0 of the remaining part of the first wall, the structural strength at the position of the first groove <NUM> is reduced to form the fragile portion <NUM>. In this structure in which the fragile portion <NUM> is formed by making the first groove <NUM> in the pressure relief region, the first groove <NUM> can be formed in the pressure relief region of the first wall by stamping, milling, laser engraving, and other processing methods. The structure is simple, and the processing is convenient, thereby helping to reduce the manufacturing cost.

In some optional embodiments, referring to <FIG> is a schematic structural sectional view of a housing <NUM> sectioned along an A-A direction when the first groove <NUM> is made on an outer surface of the first wall. The first groove <NUM> may be made on the outer surface of the first wall, and/or the first groove <NUM> is made on an inner surface of the housing <NUM>.

As an example, for ease of description, the first groove <NUM> is in a linear shape and the housing <NUM> is a cylindrical structure.

In some specific embodiments, the first groove <NUM> is made on the outer surface of the first wall. The inner space of the housing <NUM> of the battery cell <NUM> is limited, and brings inconvenience to the processing operation of the first groove <NUM>. Therefore, the first groove <NUM> made on the outer surface of the first wall increases the external space, widens the field of vision, and facilitates visual observation and the processing of the first groove <NUM>.

Alternatively, the first groove <NUM> may be made on the inner surface of the first wall. Referring to <FIG> is a schematic structural sectional view of a housing <NUM> sectioned along an A-A direction when the first groove <NUM> is made on the inner surface of the first wall. In this way, the first groove <NUM> is prevented from being exposed outside the housing <NUM>, thereby improving visual appearance of the battery cell <NUM>. In other embodiments, referring to <FIG> is a schematic structural sectional view of a housing <NUM> sectioned along an A-A direction when the first groove <NUM> is made on both the inner surface and the outer surface of the first wall. To solve the problem that the preset processing depth of the first groove <NUM> can hardly be achieved by the existing processing technology when the first groove <NUM> is made on only the inner surface of the first wall or only the outer surface of the first wall, the first groove <NUM> is made on both the inner surface and the outer surface of the first wall. The first groove <NUM> on the inner surface corresponds to the first groove on the outer surface of the first wall.

In some embodiments, the battery cell <NUM> is a cylindrical structure, and a bottom side of the first groove <NUM> is a curved face, or a bottom side of the first groove <NUM> is a flat face.

The bottom side of the first groove <NUM> means a wall face perpendicular to the second direction in the first groove <NUM>.

As an example, still referring to <FIG> are schematic structural sectional views of a housing <NUM> sectioned along an A-A direction when the bottom wall of the first groove is parallel to the inner surface and/or outer surface of the first wall. For a cylindrical battery cell <NUM>, due to a cylindrical structure of the housing <NUM>, when the bottom side of the first groove <NUM> is a curved face parallel to the inner surface or the outer surface of the first wall, the thickness of the fragile portion <NUM> is equalized at all positions, and the structural strength of the fragile portion <NUM> is relatively consistent. When the internal pressure or temperature of the battery cell <NUM> reaches the threshold, the internal pressure can be evenly released from all positions of the fragile portion <NUM>. Understandably, in other embodiments, the bottom side of the first groove <NUM> may be a curved face that is not parallel to the outer surface or the inner surface of the first wall.

In other embodiments, referring to <FIG> is a schematic structural sectional view of a housing <NUM> sectioned along an A-A direction when the bottom side of the first groove <NUM> is a flat face. The bottom side of the first groove <NUM> may be a flat face instead. The first groove <NUM> with this structure is conveniently processible. The thickness of the fragile portion <NUM> gradually decreases from flanks to center in the width direction. When the internal pressure or temperature of the battery cell <NUM> reaches the threshold, the fragile portion <NUM> is ruptured at a thinnest position. The structural strength of the fragile portion <NUM> with this structure is relatively high, and the fragile portion <NUM> is not prone to rupture under an external force other than the internal pressure or temperature.

It needs to be noted that the structure in which the bottom side of the first groove <NUM> is a curved face or a flat face is not only applicable to the battery cell <NUM> with a cylindrical structure, but also applicable to the battery cell <NUM> with a cuboidal structure or other structures.

In some embodiments, referring to <FIG> is a schematic structural exploded view of a battery cell <NUM> according to some embodiments of this application. The first wall includes a through-hole <NUM> extending along the first direction and a pressure relief sheet <NUM> covering the through-hole <NUM>. The fragile portion <NUM> is disposed on the pressure relief sheet <NUM>.

The pressure relief sheet <NUM> fits onto the through-hole <NUM> of the first wall to seal the through-hole <NUM>. As an example, the pressure relief sheet <NUM> may be fixed onto the first wall by welding such as laser welding, ultrasonic welding, or the like.

In this embodiment, the fragile portion <NUM> may be processed and formed on the pressure relief sheet <NUM> first, and then mounted on the first wall through the pressure relief sheet <NUM>. The structural processing and design of the fragile portion <NUM> are not prone to be affected by the shape of the housing <NUM> of the battery cell <NUM>, thereby helping to reduce the difficulty of processing and manufacturing the fragile portion <NUM>. In other embodiments, the first wall further includes a body portion. The body portion and the fragile portion <NUM> are integrally formed. In other words, the fragile portion <NUM> and the first wall are an integrated structure.

Optionally, the first groove <NUM> extends along the first direction. A ratio of a dimension of the first groove <NUM> in the first direction to a dimension of the first wall in the first direction is greater than <NUM>/<NUM>.

As an example, still using an example in which the first groove <NUM> is in a linear shape, the ratio of the length of the first groove <NUM> in the first direction to the length of the first wall in the first direction is <NUM>/<NUM>.

The gas pressure inside the battery cell <NUM> generally concentrates at a position close to two ends along the first direction. If the ratio of the dimension of the first groove <NUM> in the first direction to the dimension of the first wall in the first direction is greater, the fragile portion <NUM> formed by making the first groove <NUM> in the pressure relief region is closer to positions at the two ends of the battery cell <NUM> along the first direction. This effectively shortens a pressure relief path of the gas inside the battery cell <NUM>, so that the battery cell <NUM> can release pressure quickly in time when the internal temperature or pressure of the battery cell <NUM> reaches the threshold.

In some embodiments, the first groove <NUM> is made in an annular shape. With the first groove <NUM> made in an annular shape, when the internal pressure or temperature of the battery cell <NUM> reaches the threshold, the housing <NUM> of the battery cell <NUM> can rupture along an annular edge, thereby increasing the area of releasing pressure outward from the battery cell <NUM>. In this way, the internal pressure of the battery cell <NUM> can be released outward quickly in time, thereby improving the safety of the battery cell <NUM>.

It needs to be noted that the first groove <NUM> may be in a regular annular shape, or in other irregular quasi-annular shapes.

In some embodiments of this application, the first groove <NUM> is disposed around a central axis of the battery cell <NUM>, the central axis being parallel to the first direction. In other words, the fragile portion <NUM> is disposed as a circle around the central axis of the battery cell <NUM>, the central axis being parallel to the first direction. When the fragile portion is broken, the battery cell <NUM> can release pressure outward from all positions surrounded by the fragile portion <NUM>, thereby helping to shorten the path of gas exhausting and pressure release from inside to outside of the battery cell <NUM> and improve the pressure release efficiency.

In other embodiments, the central axis of the annular shape may intersect, for example, be perpendicular to, the first direction.

The first groove <NUM> may be made on the inner surface of the first wall, or the outer surface of the first wall, or both the inner surface and the outer surface of the first wall. Therefore, for ease of description, as an example in the following embodiments, the first groove <NUM> is an annular shape and is made on the outer surface of the first wall. In some embodiments, as shown in <FIG>, a second groove <NUM> is further made at a bottom wall of the first groove <NUM>. The thickness h2 of the fragile portion <NUM> at the second groove <NUM> is less than the thickness h1 of the remaining part of the fragile portion <NUM>. The pressure relief region is configured to break a bottom wall of the second groove <NUM> to release the pressure when the internal pressure or temperature of the battery cell <NUM> reaches the threshold.

By making a first groove <NUM> in the pressure relief region first and then making a second groove <NUM> on the bottom side of the first groove <NUM>, with the first groove <NUM> and the second groove <NUM> being deepened gradually in the pressure relief region, the problem of being difficult to achieve the preset processing depth of the second groove <NUM> in existing processing technology is solved, and the processing is facilitated. In addition, the thickness h2 of the fragile portion <NUM> at the second groove <NUM> is less than the thickness h1 of the remaining part of the fragile portion. Therefore, the structural strength of the fragile portion <NUM> is high, and the battery cell <NUM> is blasted at the bottom side of the second groove <NUM> when the internal pressure or temperature of the battery cell reaches the threshold, thereby achieving an effect of directional blasting.

In some embodiments, the dimension of the second groove <NUM> on the bottom side of the first groove <NUM> in the first direction may be less than or equal to the dimension of the first groove <NUM> in the first direction, without being specifically limited herein.

As shown in <FIG>, in some embodiments of this application, the first groove <NUM> includes a first part 332a and a second part 332b. The first part 332a is in communication with the second part 332b. The fragile portion <NUM> includes a first fragile portion 331a and a second fragile portion 331b. The first fragile portion 331a formed by disposing the first part 332a in the pressure relief region, and the second fragile portion 331b is formed by disposing the second part 332b in the pressure relief region. A thickness h11 of the first fragile portion 331a is less than a thickness h12 of the second fragile portion 331b. The pressure relief region is configured to break the first fragile portion 331a and avoid breaking at least a part of the second fragile portion 331b when the internal pressure or temperature of the battery cell <NUM> reaches the threshold.

As an example, the first part 332a and the second part 332b may each account for a percentage of the first groove <NUM>, such as <NUM>/<NUM> of the first groove <NUM>. For example, the first groove <NUM> is disposed in an annular shape. When a central angle corresponding to an arc length of the first part 332a is <NUM>° and a central angle corresponding to an arc length of the second part 332b is <NUM>°, the corresponding first part and second part each account for <NUM>/<NUM> of the length of the first groove.

Understandably, the allocation may be performed according to actual conditions. For example, the first part 332a accounts for <NUM>/<NUM> of the first groove <NUM>, and the second part 332b accounts for <NUM>/<NUM> of the first groove <NUM>.

In this way, when the internal pressure or temperature of the battery cell <NUM> reaches the threshold, the first fragile portion 331a is broken, but at least a part of the second fragile portion 331b remains unbroken, thereby avoiding flying debris generated by the housing when the fragile portion <NUM> is completely broken, and ensuring the safety of the battery cell.

As shown in <FIG>, in some embodiments, one part of the second groove <NUM> is made on the bottom wall of the first part 332a, and the other part of the second groove <NUM> is made on the bottom wall of the second part 332b.

In some embodiments of this application, the first wall includes two fragile portions <NUM> in the pressure relief region. The two fragile portions <NUM> are spaced apart along the first direction. By disposing two fragile portions <NUM>, when the internal pressure or temperature of the battery cell <NUM> reaches the threshold, the area of releasing pressure is increased in the pressure relief region, the pressure relief capability of the battery cell <NUM> is improved, and the safety of the battery <NUM> is further improved.

In some embodiments, a spacing between the two fragile portions <NUM> along the first direction may be set based on a capacity of the battery cell <NUM>. The higher the capacity of the battery cell <NUM>, the larger the spacing between the two fragile portions <NUM> along the first direction. In other embodiments, the number of the fragile portions <NUM> disposed along the first direction in the pressure relief region may be selected depending on the capacity or dimension of the battery cell <NUM>.

In some embodiments, referring to <FIG> is a schematic structural exploded view of a battery cell according to other embodiments of this application.

The housing <NUM> further includes a second wall. The second wall and the end cap <NUM> are connected to two ends of the first wall respectively, the two ends being opposite to each other along the first direction. The battery cell <NUM> further includes an electrode assembly <NUM>. After being wound, the electrode assembly <NUM> includes a first end face <NUM> contiguous to the end cap <NUM> and a second end face <NUM> contiguous to the second wall in the first direction.

The second wall may be another end cap <NUM> disposed at the other end of the housing <NUM>, or may be a bottom wall disposed at the bottom of the housing <NUM>.

In some embodiments, at least a part of the pressure relief region is a region located between the first end face <NUM> and the end cap <NUM> along the first direction on the first wall.

That is, a least a part of the fragile portion <NUM> is a region located between the first end face <NUM> and the end cap <NUM> that are opposite to each other on the first wall. The number of the fragile portions <NUM> may be one or more.

Generally, the gas inside the battery cell <NUM> is prone to concentrate at the two ends of the electrode assembly <NUM>. Therefore, with at least a part of the pressure relief region being located between the first end face of the electrode assembly <NUM> and the end cap <NUM> on the first wall, this application can reduce the paths for releasing outward the pressure that is generated by the gas located between the end cap <NUM> and the electrode assembly <NUM>. In this way, the internal pressure of the battery cell <NUM> can be released quickly in time when the internal pressure or temperature of the battery cell <NUM> reaches the threshold.

In some embodiments, at least a part of the pressure relief region is a region located between the second end face <NUM> and the second wall along the first direction on the first wall. That is, a least a part of the fragile portion <NUM> is a region located between the second end face <NUM> and the second wall that are opposite to each other on the first wall. The number of the fragile portions <NUM> may be one or more.

Generally, the gas inside the battery cell <NUM> is prone to concentrate at the two ends of the electrode assembly <NUM>. Therefore, with at least a part of the pressure relief region being located between the second end face <NUM> of the electrode assembly <NUM> and the second wall on the first wall, this application can reduce the paths for releasing outward the pressure that is generated by the gas located between the second wall and the second end face <NUM> of the electrode assembly <NUM>. In this way, the internal pressure of the battery cell <NUM> can be released quickly in time when the internal pressure or temperature of the battery cell <NUM> reaches the threshold.

In other embodiments, at least one fragile portion <NUM> is provided between the first end face <NUM> and the end cap <NUM> along the first direction on the first wall, and at least one fragile portion <NUM> is provided between the second end face <NUM> and the second wall along the first direction on the first wall. In this way, the gas at the two ends of the electrode assembly <NUM> can be released outward in time when the internal pressure or temperature of the battery reaches the threshold.

Understandably, in other embodiments, the pressure relief region may be a region located between the first end face <NUM> and the second end face <NUM> along the first direction on the first wall. That is, the pressure relief region is located in the middle of the housing <NUM>.

The battery cell <NUM>, the battery <NUM>, and the vehicle <NUM> according to embodiments of this application have been described above. The following describes a method for manufacturing a battery cell <NUM> according to an embodiment of this application. For information not detailed in the following embodiments, refer to the preceding embodiments.

An embodiment of this application further provides a method <NUM> for manufacturing a battery <NUM>. Referring to <FIG> is a schematic flowchart of a method for manufacturing a battery according to an embodiment of this application. The method <NUM> includes the following steps:.

A plurality of battery cells <NUM> are arranged along the first direction. The end cap <NUM> is mounted at the end of the housing <NUM> along the first direction. The pressure relief region is provided on the first wall of the housing <NUM>, the first wall being parallel to the first direction. When the internal pressure and temperature of the battery cell <NUM> reach the threshold due to overcharge or an abnormal short circuit inside the battery cell <NUM>, the internal pressure can be released outward along the second direction that intersects the first direction. In this way, the arrangement direction of the battery cells <NUM> is different from the pressure release direction of the battery cells <NUM>. Therefore, the pressure released from the pressure relief region will not cause impact or even damage to other adjacent battery cells <NUM>, thereby improving the safety of the battery <NUM> in use.

An embodiment of this application further provides a device <NUM> for manufacturing a battery <NUM>. Referring to <FIG> is a schematic structural block diagram of a device for manufacturing a battery according to an embodiment of this application. The device <NUM> includes a battery cell <NUM> manufacturing module <NUM> and an assembling module <NUM>.

Claim 1:
A battery, comprising:
a plurality of battery cells (<NUM>) arranged along a first direction, wherein each battery cell (<NUM>) is a cylindrical structure and comprises an end cap (<NUM>) and a housing (<NUM>), an opening is made at an end of the housing (<NUM>) along the first direction, the end cap (<NUM>) is configured to close the opening, and the housing (<NUM>) comprises a first wall extending along the first direction; and
a pressure relief region is provided on the first wall, the pressure relief region is configured to release pressure along a second direction when an internal pressure or temperature of the battery cell (<NUM>) reaches a threshold, and the second direction intersects the first direction, characterized in that
the first wall comprises a through-hole (<NUM>) extending along the second direction and a pressure relief sheet (<NUM>) being mounted on the first wall and covering the through-hole (<NUM>);
the pressure relief region of the first wall comprises a fragile portion (<NUM>), and the pressure relief region is configured to break the fragile portion (<NUM>) to release the pressure when the internal pressure or temperature of the battery cell (<NUM>) reaches the threshold; and the fragile portion (<NUM>) is disposed on the pressure relief sheet (<NUM>).