Stretch-molded shell and single battery

Abstract

The embodiment of the invention provides a stretch-molded shell and a single battery, the shell comprises an end wall and a side wall which is connected with the end wall and extends along a stretching direction of the end wall, the end wall and the side wall form an accommodating space, and one end, deviating from the end wall, of the side wall is provided with an opening part; the side wall comprises a preset area and a cutting area which are sequentially connected in the stretching direction, the cutting area is formed by cutting the position of the opening part, the preset area comprises a metal base material and a first nickel layer arranged on the outer surface of the metal base material, the outer surface of the metal base material in the preset area deviates from the containing space, and the metal base material is a steel base material; in the stretching direction, the thickness of the first nickel layer close to the end wall is larger than that of the first nickel layer far away from the end wall, and the thickness of the first nickel layer is larger than or equal to 1.1 microns. By applying the embodiment of the invention, the service life of the single battery can be prolonged.

Description

Technical Field

[0001] This application relates to the field of battery technology, and in particular to a stretch-formed casing and a single battery cell. Background Technology

[0002] Individual batteries are widely used in electronic devices such as mobile phones, laptops, electric vehicles, electric cars, electric airplanes, electric ships, electric toy cars, electric toy ships, electric toy airplanes, and power tools, etc.

[0003] In the field of battery technology, it is necessary to consider not only the safety of individual battery cells but also their lifespan. Therefore, improving the lifespan of individual battery cells is a technical problem that urgently needs to be solved. Summary of the Invention

[0004] The purpose of this application is to provide a stretch-formed casing and a single battery cell to improve the service life of the single battery cell. The specific technical solution is as follows:

[0005] An embodiment of the first aspect of this application provides a stretched shell, the shell including an end wall and a side wall connected to the end wall and extending along a stretching direction therein, the end wall and the side wall forming a receiving space, and an opening provided at one end of the side wall away from the end wall; the side wall includes a predetermined region and a cutting region connected sequentially along the stretching direction, the cutting region being formed by cutting the opening position, the predetermined region including a metal substrate and a first nickel layer disposed on the outer surface of the metal substrate, the outer surface of the metal substrate in the predetermined region being away from the receiving space, the metal substrate being a steel substrate, and along the stretching direction, the thickness of the first nickel layer near the end wall is greater than the thickness away from the end wall, and the thickness of the first nickel layer is greater than or equal to 1.1 μm.

[0006] In some embodiments of this application, the preset region further includes a second nickel layer disposed on the inner surface of the metal substrate, the inner surface facing the receiving space, along the stretching direction, the thickness of the second nickel layer near the end wall is greater than its thickness away from the end wall, the thickness of the second nickel layer is greater than or equal to 1.1 μm, and at a position equidistant from the opening of the side wall, the thickness of the first nickel layer is greater than the thickness of the second nickel layer.

[0007] In some embodiments of this application, the thickness of the first nickel layer is greater than or equal to 1.7 μm; at a position at the same distance from the opening of the sidewall, the ratio of the thickness of the first nickel layer to the thickness of the second nickel layer is greater than or equal to 1.1.

[0008] In some embodiments of this application, the end wall includes a metal substrate and a third nickel layer disposed on the outer surface of the metal substrate of the end wall. The outer surface of the metal substrate of the end wall is away from the receiving space. The thickness T3 of the third nickel layer is greater than the thickness of the first nickel layer and satisfies: T3-T1≤2.0μm, T2-T1≤0.5μm, where T1 is the thickness of the first nickel layer at the position of the preset region near the cutting area, T2 is the thickness of the first nickel layer in the middle part of the preset region, and the units of T1, T2 and T3 are all μm.

[0009] In some embodiments of this application, the end wall includes a fourth nickel layer disposed on the inner surface of the metal substrate of the end wall, the inner surface of the metal substrate of the end wall facing the receiving space, and the thickness of the fourth nickel layer is greater than the thickness of the second nickel layer.

[0010] In some embodiments of this application, the height of the sidewall of the housing along the stretching direction is greater than or equal to 70 mm, or the outer diameter of the housing is greater than or equal to 40 mm.

[0011] An embodiment of the second aspect of this application provides a single-cell battery, comprising:

[0012] The battery casing is a stretch-formed casing as described in any of the above embodiments; an opening is provided at one end of the side wall away from the end wall, and a roller groove recessed into the battery casing is provided at the position of the preset region near the opening; the thickness of the first nickel layer in both the roller groove region and the non-roller groove region of the preset region is greater than or equal to 1.1 μm;

[0013] The pole has a pole hole on its end wall, the pole passes through the pole hole, and is insulated and fixed to the end wall;

[0014] An electrode assembly is disposed inside the battery casing. The electrode assembly includes a first electrode, a second electrode, and a separator layered and wound together to form a wound body. The winding axis of the wound body is perpendicular to the end wall.

[0015] A cover plate, which is sealed at the opening.

[0016] In some embodiments of this application, the preset region further includes a second nickel layer disposed on the inner surface of the metal substrate, wherein the ratio of the thickness of the second nickel layer in the groove region of the preset region to the thickness of the second nickel layer in the non-groove region of the preset region is greater than or equal to 0.6, or the ratio of the thickness of the first nickel layer in the groove region of the preset region to the thickness of the second nickel layer in the groove region of the preset region ranges from 1.5 to 2.5.

[0017] In some embodiments of this application, the thickness difference between the first nickel layer at the position near the end wall in the preset region and the thickness difference between the first nickel layer in the roll groove region is less than or equal to 0.6 μm.

[0018] In some embodiments of this application, along the extension direction of the sidewall body, at various locations equidistant from the outer surface of the end wall within the roll groove region, the various locations are circumferentially distributed within the roll groove region, and the standard deviation Sigma of the first nickel layer thickness at each location is <0.14.

[0019] Beneficial effects of the embodiments in this application:

[0020] The stretched-formed housing and single battery provided in this application embodiment include a sidewall of the housing comprising a preset area and a cutting area connected sequentially along a stretching direction. A first nickel layer is provided on the outer surface of the metal substrate in the preset area. Along the stretching direction, the thickness of the first nickel layer near the end wall is greater than the thickness away from the end wall. That is, when the thickness of the first nickel layer on the sidewall decreases along the stretching direction, it is necessary to ensure that the thickness of the first nickel layer is greater than or equal to 1.1 μm. This improves the rust resistance of the thinnest part of the first nickel layer in the preset area and reduces the risk of rust in the preset area of ​​the housing.

[0021] The single-cell battery assembled using the stretch-formed casing provided in this application embodiment has a lower risk of rusting in the pre-defined area of ​​the casing during later use, thus improving the service life of the single-cell battery.

[0022] Of course, implementing any product or method of this application does not necessarily require achieving all of the advantages described above at the same time. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other embodiments can be obtained based on these drawings.

[0024] Figure 1 This is a schematic diagram of an electrical device used in a vehicle, as provided in an embodiment of this application.

[0025] Figure 2 A schematic diagram of a battery provided for an embodiment of this application;

[0026] Figure 3 A perspective view of a single battery cell provided in an embodiment of this application;

[0027] Figure 4 for Figure 3 A schematic cross-sectional view of a single cell shown;

[0028] Figure 5 A cross-sectional view of a stretch-formed shell provided in an embodiment of this application;

[0029] Figure 6 for Figure 5 A schematic diagram of one possible structure of the shell shown;

[0030] Figure 7 for Figure 5 A partial schematic diagram of the sidewall of the shell shown at the end furthest from the end wall;

[0031] Figure 8 for Figure 4 An enlarged schematic diagram of point A in the single cell shown.

[0032] Figure label:

[0033] 1. Battery casing; 2. Terminal posts; 3. Electrode assembly; 4. Cover plate; 5. Sealing ring;

[0034] Shell 10; Roller trough 20; Trough wall 21; Transition section 22;

[0035] End wall 101; pole hole 1011; side wall 102; preset area 102a; cutting area 102b; opening 1021; tear strip 1022; bright strip 1023; receiving space 103; flange 104;

[0036] Metal substrate 100; First nickel layer 110; Second nickel layer 120; Third nickel layer 130; Fourth nickel layer 140;

[0037] Vehicle 1000; Body 1001; Battery 1002; Box 10021; Box Cover 10022; Secondary Battery 10023. Detailed Implementation

[0038] The technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art based on this application are within the scope of protection of this application.

[0039] The battery disclosed in this application refers to a single physical module comprising one or more individual cells to provide higher voltage and capacity. It is widely used in various electrical devices, including but not limited to mobile phones, tablets, laptops, electric toys, power tools, electric vehicles, electric cars, ships, and spacecraft. Electric toys can include stationary or mobile electric toys, such as game consoles, electric car toys, electric ship toys, and electric airplane toys. Power tools include metal cutting power tools, grinding power tools, assembly power tools, and railway power tools, such as electric drills, electric grinders, electric wrenches, electric screwdrivers, electric hammers, impact drills, concrete vibrators, and electric planers. Spacecraft can include airplanes, rockets, space shuttles, and spacecraft.

[0040] The working part of the electrical device is connected to a battery to obtain electrical power. For ease of explanation, the following embodiments use a vehicle 1000 as an example of an electrical device according to an embodiment of this application.

[0041] See Figure 1 , Figure 1 This is a schematic diagram illustrating an electrical device provided in an embodiment of this application when it is a vehicle. The vehicle 1000 can be a gasoline-powered vehicle, a natural gas-powered vehicle, or a new energy vehicle. New energy vehicles can be pure electric vehicles, hybrid electric vehicles, or range-extended electric vehicles, but are not limited thereto. The vehicle 1000 includes a body 1001 and a battery 1002 disposed within the body. The battery 1002 can be located at the bottom, front, or rear of the vehicle 1000. The battery 1002 can be used to power the vehicle 1000; for example, the battery 1002 can serve as the operating power source for the vehicle 1000. The vehicle 1000 may also include a controller and a motor. The controller is used to control the battery 1002 to supply power to the motor, for example, to meet the power needs of the vehicle 1000 during startup, navigation, and driving.

[0042] See Figure 2 , Figure 2This is a schematic diagram of a battery provided in an embodiment of this application. The battery 1002 mentioned in this application embodiment includes a secondary battery 10023 and a busbar. In one embodiment of the battery 1002, the battery 1002 includes a housing 10021, a cover 10022, and multiple secondary batteries 10023. The multiple secondary batteries 10023 are placed in the housing 10021 and are connected in series or parallel, or a combination of series and parallel connections. The busbar is connected in series or parallel to the electrode terminals of the secondary batteries 10023. The cover 10022 covers the housing 10021 to protect the multiple secondary batteries 10023. It should be noted that the secondary battery 10023 in this application is a single cell. It should also be noted that the battery 1002 may include a battery thermal management system, circuit board, etc., in addition to the secondary battery 10023. The battery 1002 can be a battery module, a battery pack, an energy storage cabinet, etc.; these will not be described in detail here.

[0043] For ease of explanation, the following embodiments use a cylindrical battery as an example from one embodiment of this application. See also... Figure 3 and Figure 4 , Figure 3 A perspective view of a single battery cell provided in an embodiment of this application; Figure 4 for Figure 3 The diagram shows a cross-sectional view of a single battery cell. The single battery cell in this embodiment includes: a battery casing 1, an electrode assembly 3, and a cover plate 4. The battery casing 1 has an opening on one side, and the cover plate 4 is disposed to seal the opening of the battery casing 1.

[0044] The battery casing 1 is a component used to cooperate with the cover plate 4 to form the internal environment of a single cell, wherein the formed internal environment can be used to accommodate the electrode assembly 3, electrolyte and other components.

[0045] In the field of battery technology, the battery casing 1 is usually manufactured using a stamping process. Stamping is a technology that uses a mold to press a metal sheet into the desired shape. It has advantages such as high production efficiency, high material utilization, and the ability to adapt to complex shapes, so it is often used in the processing of battery casing 1.

[0046] To reduce the risk of rust on the battery casing 1, the metal sheet is typically nickel-plated. Depending on the order in which the nickel plating process occurs, it can be divided into two types: post-plating and pre-plating. Post-plating involves first stamping the metal sheet, then plating the resulting battery casing 1 with nickel; pre-plating involves plating the metal sheet with nickel before stamping it into the battery casing 1.

[0047] For pre-plated nickel shells, during the stamping process, the second nickel layer and the first nickel layer located on the inner and outer surfaces of the metal substrate are stretched multiple times. The height of the battery shell 1 will increase with stretching, and the second nickel layer and the first nickel layer will be thinned during the stretching process. When the nickel layer thickness is too thin, the outer surface of the battery shell 1 is prone to rust, which affects the mechanical strength of the shell and the service life after the shell is assembled into a single battery.

[0048] In view of this, embodiments of this application provide a stretch-formed housing to reduce the risk of rust in a predetermined area of ​​the housing, thereby improving the service life of a single battery cell.

[0049] See Figure 5 and Figure 6 , Figure 5 A cross-sectional view of a stretch-formed shell provided in an embodiment of this application; Figure 6 for Figure 5 A schematic diagram of one structure of the shell shown.

[0050] This application provides a stretched shell, the shell 10 including an end wall 101 and a side wall 102 connected to the end wall 101 and extending along a stretching direction therefrom, the end wall 101 and the side wall 102 forming a receiving space 103, the side wall 102 having an opening 1021 at one end away from the end wall 101; the side wall 102 including a predetermined region 102a and a cutting region 102b connected sequentially along the stretching direction, the cutting region 102b being formed at the location of the cutting opening 1021, the predetermined region 102a including a metal substrate 100 and a first nickel layer 110 disposed on the outer surface of the metal substrate 100, the outer surface of the metal substrate 100 in the predetermined region 102a being away from the receiving space 103, the metal substrate 100 being a steel substrate, along the stretching direction, the thickness of the first nickel layer 110 near the end wall 101 is greater than the thickness away from the end wall 101, and the thickness of the first nickel layer 110 is greater than or equal to 1.1 μm.

[0051] like Figure 5 As shown, the housing 10 has two stretching directions: one stretching direction is parallel to the end wall 101, and the other stretching direction is parallel to the side wall 102. The aforementioned stretching direction refers to the stretching direction parallel to the side wall 102. The end wall 101 includes an electrode post hole 1011 for through which the electrode post is disposed. In a specific embodiment of this application, as... Figure 6 As shown, the sidewall 102 consists of a preset area 102a and a cutting area 102b connected sequentially along the stretching direction parallel to the sidewall 102.

[0052] like Figure 6As shown, the cutting area 102b refers to the area formed when the opening edge of the metal sheet is cut after it has been stretched and formed. The opening 1021 refers to the end face of the cutting area 102b away from the end wall 101. The cutting area 102b may consist only of a metal substrate; it may also include a metal substrate and a nickel layer disposed on the outer surface of the metal substrate to improve the rust resistance of the cutting area 102b. When the side wall 102 is... Figure 6 In the vertical configuration shown, the cutting area 102b extends 2mm-4mm away from the end wall 101 of the side wall 102, away from the stretching direction. When the side wall 102 has a lateral bend or fold, the cutting area 102b extends 2mm-4mm along the extending direction of the side wall 102 body from the end wall 101. Optionally, the cutting area 102b extends 2mm along the extending direction of the side wall 102 body from the end wall 101. Optionally, the cutting area 102b extends 4mm along the extending direction of the side wall 102 body from the end wall 101. When the side wall 102 is thicker, the dimension of the cutting area 102b in its extending direction is larger. The aforementioned steel substrate includes base iron and an iron-nickel alloy layer on the surface of the base iron.

[0053] The thickness of the sidewall 102 ranges from 0.3mm to 0.9mm. Specifically, the thickness of the sidewall 102 can be 0.3mm, 0.4mm, 0.5mm, 0.7mm, or 0.9mm. The thickness of the endwall 101 ranges from 0.4mm to 0.9mm. Specifically, the thickness of the endwall 101 can be 0.4mm, 0.5mm, 0.8mm, or 0.9mm. Limiting the thickness of the endwall 101 and the sidewall 102 to the above ranges ensures that the shell 10 has high structural strength. Since the end wall 101 is used to fix the pole post, setting the thickness of the end wall 101 to be thicker than the thickness of the side wall 102 can give the end wall 101 better support. Setting the side wall 102 to be thinner can avoid the loss of volumetric energy density and the increase in cost caused by the side wall 102 being too thick. In addition, it can also allow the nickel layer thickness of the end wall 101 to the nickel layer thickness of the side wall 102 to decrease in a gradient, avoiding the reduction of nickel layer density or damage to the nickel layer caused by stretching.

[0054] The stretched-formed housing 10 provided in this application embodiment has a first nickel layer 110 with a thickness greater near the end wall 101 than with a thickness further away from the end wall 101. That is, when the thickness of the first nickel layer 110 on the side wall 102 decreases along the stretching direction parallel to the side wall 102, the thickness of the first nickel layer 110 needs to be greater than or equal to 1.1 μm. This improves the rust resistance of the thinnest part of the first nickel layer 110 in the preset region 102a, reducing the risk of rust in the preset region 102a of the housing 10. In later use, the single-cell battery assembled using the stretched-formed housing 10 provided in this application embodiment has a lower risk of rust in the preset region 102a of the housing 10, thus improving the service life of the single-cell battery.

[0055] It should be noted that, in order to visually show the location of each nickel layer, Figure 6 The thickness of each nickel layer shown is not to scale.

[0056] In some embodiments of this application, such as Figure 6 As shown, the preset region 102a also includes a second nickel layer 120 disposed on the inner surface of the metal substrate 100, with the inner surface facing the receiving space 103. Along the stretching direction parallel to the sidewall 102, the thickness of the second nickel layer 120 near the end wall 101 is greater than its thickness away from the end wall 101, and the thickness of the second nickel layer 120 is greater than or equal to 1.1 μm. At the same distance from the opening 1021 of the sidewall 102, the thickness of the first nickel layer 110 is greater than the thickness of the second nickel layer 120.

[0057] By providing a second nickel layer 120 on the inner surface of the metal substrate 100 in the preset region 102a, the rust resistance of the inner surface of the preset region 102a can be improved. By limiting the thickness of the second nickel layer 120, the risk of rust on the inner surface of the preset region 102a is reduced, and the risk of electrolyte corrosion on the inner surface of the preset region 102a can also be reduced after it is assembled into a single battery cell.

[0058] Since the outer surface of the preset region 102a is exposed to the external environment such as air for a long time, the inner surface of the preset region 102a will rust less after being assembled into a single battery in a sealed environment. Therefore, this embodiment of the application limits the thickness of the first nickel layer 110 to be greater than the thickness of the second nickel layer 120 at a position at the same distance from the opening 1021 of the side wall 102. This can further improve the rust resistance of the outer surface of the preset region 102a, and reduce the cost of the second nickel layer 120 thickness while ensuring that the inner surface of the preset region 102a has sufficient protection.

[0059] In some embodiments of this application, the thickness of the first nickel layer 110 is greater than or equal to 1.7 μm, and at a position at the same distance from the opening 1021 of the sidewall 102, the ratio of the thickness of the first nickel layer 110 to the thickness of the second nickel layer 120 is greater than or equal to 1.1, thereby further improving the rust resistance of the outer surface of the preset area 102a.

[0060] In some embodiments of this application, such as Figure 6 As shown, the end wall 101 includes a metal substrate 100 and a third nickel layer 130 disposed on the outer surface of the metal substrate 100 of the end wall 101. The outer surface of the metal substrate 100 of the end wall 101 is away from the receiving space 103. The thickness T3 of the third nickel layer 130 is greater than the thickness of the first nickel layer 110 and satisfies: T3-T1≤2.0μm, T2-T1≤0.5μm. Wherein, T1 is the thickness of the first nickel layer 110 at the position of the preset region 102a near the cutting area 102b, T2 is the thickness of the first nickel layer 110 in the middle part of the preset region 102a, and the units of T1, T2 and T3 are all μm.

[0061] By defining the relationship between T1, T2, and T3, it is ensured that after the shell 10 is stretched, a first nickel layer 110 with a thickness gradient distribution can be formed on the outer surface of the shell 10 from the end wall 101 to the side wall 102 in the preset region 102a near the cutting area 102b. This not only satisfies the rust prevention function of the outer surface of the shell 10, but also ensures that the first nickel layer 110 on the outer surface of the shell 10 will not have uneven nickel layer density due to the huge thickness gradient difference, thus affecting the rust prevention ability of the outer surface of the shell 10.

[0062] In some embodiments of this application, such as Figure 6 As shown, the end wall 101 includes a fourth nickel layer 140 disposed on the inner surface of the metal substrate 100 of the end wall 101. The inner surface of the metal substrate 100 of the end wall 101 faces the receiving space 103, and the thickness of the fourth nickel layer 140 is greater than the thickness of the second nickel layer 120. By limiting the thickness of the fourth nickel layer 140, the inner surface of the end wall 101 also has a relatively thick fourth nickel layer 140, and the thickness of the fourth nickel layer 140 is greater than the second nickel layer 120 on the inner surface of the preset region 102a of the side wall 102, thereby giving the inner surface of the end wall 101 stronger rust resistance.

[0063] In some embodiments of this application, the height of the sidewall 102 of the housing 10 along the stretching direction parallel to the sidewall 102 is greater than or equal to 70 mm. Since the number of stretching cycles increases when the housing 10 is taller, and the more stretching cycles there are, the greater the damage to the nickel layer on the surface of the housing 10. In the embodiments of this application, when the height of the sidewall 102 along the stretching direction parallel to the sidewall 102 is greater than or equal to 70 mm, the thickness of the first nickel layer 110 still meets the requirement of being greater than or equal to 1.1 μm, thus ensuring the rust prevention capability of the outer surface of the preset area 102a of the large-size housing 10.

[0064] In some embodiments of this application, the outer diameter of the housing 10 is greater than or equal to 40 mm. For example, taking a 4680 cylindrical battery as an example, its outer diameter is 46 mm. Since it is more difficult to stretch the housing 10 when the outer diameter is larger, it will cause more damage to the nickel layer on the surface of the housing 10. In the embodiments of this application, when the outer diameter of the housing 10 is greater than or equal to 40 mm, the thickness of the first nickel layer 110 still meets the requirement of being greater than or equal to 1.1 μm, which improves the rust resistance of the outer surface of the preset area 102a of the large-size housing 10.

[0065] The housing 10 can be a cylindrical housing, a square housing, or a polygonal housing. When the housing 10 is a square housing, the diagonal length of the end wall 101 is greater than or equal to 40 mm. When the housing 10 is a polygonal housing, the maximum diagonal length of the end wall 101 is greater than or equal to 40 mm.

[0066] In some embodiments of this application, the housing 10 is obtained by at least five stretching operations. By limiting the number of stretching operations of the housing 10, even after multiple stretching operations and repeated damage to the nickel layer, a relatively thick first nickel layer 110 is still present on the predetermined area 102a of the sidewall 102 of the housing 10, thereby improving the rust resistance of the outer surface of the predetermined area 102a of the housing 10.

[0067] The housing 10 of this application embodiment can be pre-plated with nickel or post-plated with nickel during preparation, and this application does not limit the method of production. When pre-plating with nickel, in order to ensure that the thickness of the nickel layer on the inner and outer surfaces of the housing 10 meets the above conditions, a pre-plated nickel steel plate with a thicker nickel layer can be used to stamp the housing 10, or the number of stretching operations can be controlled during the stamping process of the pre-plated nickel steel plate. This application does not limit the method of producing the housing 10.

[0068] See Figure 7 , Figure 7 for Figure 5 The diagram shows a partial view of the sidewall of the casing at the end furthest from the end wall. (See attached image.) Figure 7As shown, at the end of the sidewall 102 away from the endwall 101, the sidewall 102 includes: an opening 1021, a tear strip 1022, and a bright strip 1023 connected in sequence. The tear strip 1022 and the bright strip 1023 are located in the cutting area 102b.

[0069] The tear strip 1022 is located within a distance of 0.05mm-0.2mm from the opening 1021 along the extension direction of the sidewall 102 body, and the bright strip 1023 is located within a distance of 0.2mm-0.4mm from the opening 1021 along the extension direction of the sidewall 102 body. Only a very small amount of residual nickel layer remains on the opening 1021, while no nickel layer is distributed on the tear strip 1022 and the bright strip 1023. Therefore, when installing the electrode assembly 3 and filling it with electrolyte in the housing 10, contact between the electrolyte and the cutting area 102b must be avoided to ensure the safety of the single cell during use. Otherwise, the electrolyte may easily corrode the opening 1021, the tear strip 1022, and the bright strip 1023.

[0070] In some embodiments of this application, the cover plate 4 of the single battery cell and the battery casing 1 can be directly welded together for sealing, or as follows: Figure 4 The mechanical seal shown uses the roller groove 20. Compared to direct welding, the mechanical seal using the roller groove 20 can improve production efficiency. Processing the roller groove 20 further reduces the thickness of the first nickel layer 110 and the second nickel layer 120 on the preset area 102a. The following will discuss... Figure 4 The structure of a single cell with a mechanical seal using a roller groove 20 is illustrated below.

[0071] This application provides a single-cell battery, such as... Figure 4 As shown, the single battery includes a battery casing 1, a terminal post 2, an electrode assembly 3, and a cover plate 4. The battery casing 1 is a stretched casing 10 as described in any of the above embodiments. An opening 1021 is provided at one end of the side wall 102 away from the end wall 101. A roller groove 20 recessed into the battery casing 1 is provided near the opening 1021 in the preset region 102a. The thickness of the first nickel layer 110 in both the roller groove region and the non-roller groove region of the preset region 102a is greater than or equal to 1.1 μm. A terminal post hole 1011 is provided on the end wall 101. The terminal post 2 passes through the terminal post hole 1011 and is insulated and fixed to the end wall 101. The electrode assembly 3 is disposed inside the battery casing 1. The electrode assembly 3 includes a first electrode, a second electrode, and a separator layered and wound together to form a wound body. The winding axis of the wound body is perpendicular to the end wall 101. The cover plate 4 is sealed at the opening 1021.

[0072] The cutting area 102b is located on the side of the roller groove 20 away from the electrode assembly 3, which can avoid the area inside the battery that comes into contact with the electrolyte, so as to ensure the safety of the single cell during use.

[0073] The first electrode is electrically connected to the terminal 2, and the second electrode is electrically connected to the battery casing 1. One of the first electrode and the second electrode is a positive electrode, and the other is a negative electrode.

[0074] The single battery provided in this application embodiment has a battery casing 1 that is a stretched casing 10 as described in any of the above embodiments. Since the processing of the groove 20 will further reduce the thickness of the first nickel layer 110 on the preset area 102a, this application embodiment limits the thickness of the first nickel layer 110 in both the groove area and the non-groove area of ​​the preset area 102a to be greater than or equal to 1.1 μm. This ensures that the first nickel layer 110 in the preset area 102a of the single battery will not be too thin due to the presence of the groove 20, thus ensuring that the battery casing 1 of the single battery meets the long-term rust prevention capability of the outer surface of the battery after being stretched by the groove, reducing the risk of rust in the groove area, and thereby improving the service life of the single battery.

[0075] like Figure 4 As shown, the roller groove 20 is located on the side wall 102. The vertical distance between the roller groove 20 and the outer surface of the end wall 101 of the battery housing 1 accounts for about 90% of the total height of the battery housing 1, so as to leave enough space to install the electrode assembly 3 and restrict the displacement of the electrode assembly 3 along the height direction of the battery housing 1. The total height of the battery housing 1 is the vertical distance from the outer surface of the end wall 101 of the battery housing 1 to the opening 1021.

[0076] In some embodiments of this application, the preset region 102a further includes a second nickel layer 120 disposed on the inner surface of the metal substrate 100, wherein the ratio of the thickness of the second nickel layer 120 in the groove region of the preset region 102a to the thickness of the second nickel layer 120 in the non-groove region of the preset region 102a is greater than or equal to 0.6.

[0077] This application embodiment improves the safety of a single battery during use by limiting the minimum value of the ratio of the thickness of the second nickel layer 120 in the grooved area and the non-grooved area of ​​the preset region 102a. It avoids the second nickel layer 120 inside the groove 20 being stretched after being stretched by the groove, which would cause the inner surface of the metal substrate 100 to be corroded by the electrolyte, thus causing battery safety problems caused by leakage of the single battery. For example, the inner surface of the preset region 102a is corroded by the electrolyte, producing foreign objects. These foreign objects fall into the receiving space 103 and rust through the separator in the winding body, causing a short circuit between the first electrode and the second electrode.

[0078] In some embodiments of this application, the ratio of the thickness of the first nickel layer 110 in the roll groove region of the preset region 102a to the thickness of the second nickel layer 120 in the roll groove region of the preset region 102a ranges from 1.5 to 2.5.

[0079] This embodiment limits the maximum ratio of the thickness of the first nickel layer 110 and the second nickel layer 120 within the roll groove region to avoid a significant difference in the thinning degree of the first nickel layer 110 and the second nickel layer 120 after roll groove stretching, which would result in poor density of the second nickel layer 120. Since the second nickel layer 120 primarily serves an anti-corrosion function, and the first nickel layer 110 needs to provide rust prevention throughout the battery's lifespan, this embodiment limits the minimum ratio of the thickness of the first nickel layer 110 and the second nickel layer 120 within the roll groove region to avoid excessively thick second nickel layer 120 in the roll groove region, which would lead to higher costs.

[0080] In some embodiments of this application, the thickness difference between the first nickel layer 110 at a position near the end wall 101 on the preset region 102a and the thickness of the first nickel layer 110 in the roll groove region is less than or equal to 0.6 μm.

[0081] By limiting the maximum thickness difference, it is possible to ensure that after the first nickel layer 110 is thinned by multiple stretching and roller groove stretching during the shell forming stage, the thickness difference of the first nickel layer 110 on the preset area 102a can also be taken into account. The thickness of the first nickel layer 110 varies in a certain gradient to satisfy the consistency of the first nickel layer 110 in the extension direction of the side wall 102 body. The first nickel layer 110 has good density, thereby improving the rust resistance of the outer surface of the preset area 102a, especially the outer surface of the roller groove area.

[0082] In some embodiments of this application, along the extending direction of the sidewall 102 body, at various locations equidistant from the outer surface of the endwall 101 within the roller groove region, each location is circumferentially distributed within the roller groove region, and the standard deviation Sigma of the thickness of the first nickel layer 110 at each location is <0.14. By limiting the standard deviation, the uniformity of the thickness of the first nickel layer 110 in the roller groove region can be improved, reducing the varying degrees of damage to the circumferential direction of the first nickel layer 110 during the manufacturing of the roller groove 20, avoiding locations where the first nickel layer 110 is too thin in the roller groove region, and reducing the uneven stress caused by stretching during the manufacturing of the roller groove 20, thereby improving the airtightness of the battery casing 1.

[0083] In some embodiments of this application, when calculating the standard deviation, the thickness of the first nickel layer 110 can be measured at eight locations uniformly distributed circumferentially in the roller groove region at locations equidistant from the outer surface of the end wall 101 within the roller groove region, along the extending direction of the sidewall 102 body.

[0084] See Figure 8 , Figure 8 for Figure 4 An enlarged schematic diagram of point A in the single cell shown.

[0085] The aforementioned roller groove area is Figure 8The U-shaped region shown by the double-arrow leader includes two upper and lower groove walls 21, and a transition section 22 connecting the ends of the two groove walls 21.

[0086] When assembling a single battery cell, the electrode assembly 3 is first placed into the housing 10, and then the roller groove 20 is machined to restrict the axial displacement of the electrode assembly 3. The open end of the side wall 102 is bent toward the axis of the battery housing 1 to form a flange 104, and the cover plate 4 is sealed between the groove wall 21 of the roller groove 20 and the flange 104.

[0087] In addition, a sealing ring 5 is provided between the cover plate 4 and the side wall 102, and the flange 104 presses the cover plate 4 tightly onto the sealing ring 5, thereby improving the sealing performance of the battery casing 1.

[0088] Those skilled in the art should understand that the single cell described above is only a typical structure of the embodiments of this application, and the single cell of this application is not limited to this typical structure. Single cells using the stretch-formed shell provided in the embodiments of this application are all within the protection scope of this application.

[0089] It should be noted that, in this document, relational terms such as "first" and "second" are used only to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0090] The above description is merely a preferred embodiment of this application and is not intended to limit the scope of protection of this application. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this application are included within the scope of protection of this application.

Claims

1. A stretched-formed housing, the housing comprising an end wall and a side wall connecting the end wall and extending along a stretching direction thereof, the end wall and the side wall forming a receiving space, the side wall having an opening at one end facing away from the end wall; the side wall comprising a predetermined region and a cutting region sequentially connected along the stretching direction, the cutting region being formed by cutting the opening, the predetermined region comprising a metal substrate and a first nickel layer disposed on the outer surface of the metal substrate, the outer surface of the metal substrate in the predetermined region facing away from the receiving space, the metal substrate being a steel substrate, characterized in that... Along the stretching direction, the thickness of the first nickel layer near the end wall is greater than the thickness away from the end wall, and the thickness of the first nickel layer is greater than or equal to 1.1 μm.

2. The stretched shell according to claim 1, characterized in that, The preset area further includes a second nickel layer disposed on the inner surface of the metal substrate, the inner surface facing the receiving space. Along the stretching direction, the thickness of the second nickel layer near the end wall is greater than its thickness away from the end wall, and the thickness of the second nickel layer is greater than or equal to 1.1 μm. At the same distance from the opening of the side wall, the thickness of the first nickel layer is greater than the thickness of the second nickel layer.

3. The stretch-formed shell according to claim 2, characterized in that, The thickness of the first nickel layer is greater than or equal to 1.7 μm; at a position at the same distance from the opening of the sidewall, the ratio of the thickness of the first nickel layer to the thickness of the second nickel layer is greater than or equal to 1.

1.

4. The stretched shell according to claim 1, characterized in that, The end wall includes a metal substrate and a third nickel layer disposed on the outer surface of the metal substrate of the end wall. The outer surface of the metal substrate of the end wall faces away from the receiving space. The thickness T3 of the third nickel layer is greater than the thickness of the first nickel layer. And satisfy: T3-T1≤2.0μm, T2-T1≤0.5μm, where T1 is the thickness of the first nickel layer near the cutting area of ​​the preset region, T2 is the thickness of the first nickel layer in the middle part of the preset region, and the units of T1, T2 and T3 are all μm.

5. The stretch-formed shell according to claim 2, characterized in that, The end wall includes a fourth nickel layer disposed on the inner surface of the metal substrate of the end wall, the inner surface of the metal substrate of the end wall facing the receiving space, and the thickness of the fourth nickel layer is greater than the thickness of the second nickel layer.

6. The stretched shell according to claim 1, characterized in that, The height of the sidewall of the housing along the stretching direction is greater than or equal to 70 mm, or the outer diameter of the housing is greater than or equal to 40 mm.

7. A single-cell battery, characterized in that, include: A battery casing, wherein the battery casing is a stretch-formed casing as described in any one of claims 1 to 6; The sidewall is provided with an opening at one end away from the endwall, and the preset area includes a roller groove recessed into the battery casing at a position near the opening; the thickness of the first nickel layer in both the roller groove area and the non-roller groove area of ​​the preset area is greater than or equal to 1.1 μm. The pole has a pole hole on its end wall, the pole passes through the pole hole, and is insulated and fixed to the end wall; An electrode assembly is disposed inside the battery casing. The electrode assembly includes a first electrode, a second electrode, and a separator layered and wound together to form a wound body. The winding axis of the wound body is perpendicular to the end wall. A cover plate, which is sealed at the opening.

8. The single-cell battery according to claim 7, characterized in that, The preset region further includes a second nickel layer disposed on the inner surface of the metal substrate, wherein the ratio of the thickness of the second nickel layer in the grooving region of the preset region to the thickness of the second nickel layer in the non-grooving region of the preset region is greater than or equal to 0.6, or... The ratio of the thickness of the first nickel layer in the roll groove region of the preset area to the thickness of the second nickel layer in the roll groove region of the preset area ranges from 1.5 to 2.

5.

9. The single-cell battery according to claim 7, characterized in that, The thickness difference between the first nickel layer at the position near the end wall in the preset area and the thickness of the first nickel layer in the roll groove area is less than or equal to 0.6 μm.

10. The single-cell battery according to claim 7, characterized in that, Along the extending direction of the sidewall body, at various locations within the roller groove region that are equidistant from the outer surface of the end wall, the various locations are circumferentially distributed within the roller groove region, and the standard deviation of the first nickel layer thickness at each location is Sigma < 0.14.

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