Battery cell and preparation method therefor

Abstract

A battery cell and a preparation method therefor. The battery cell comprises a casing (1). The casing (1) comprises at least one plate (10), a connecting portion (11), and a cladding layer (12). The connecting portion (11) is connected to the plate (10), and the plate (10) and the connecting portion (11) define an accommodating cavity. Regarding the cladding layer (12), the cladding layer (12) is provided on the side of the plate (10) distant from the accommodating cavity, and the cladding layer (12) covers the connecting portion (11). In a laser cladding process, the scanning rate of a laser beam relative to the connecting portion (11) is 50-500 mm / s; and the laser power in the laser cladding process is 0.8-5 kW.

Description

Single cell and preparation method thereof

[0001] This application claims priority to the Chinese patent application filed with the China Patent Office on January 25, 2024, with application number 202410101130.8 and invention name “Single Cell and Its Preparation Method”, the entire contents of which are incorporated by reference into this application. Technical Field

[0002] The present application relates to, but is not limited to, the field of laser cladding technology. Background Art

[0003] In blade lithium-ion batteries, the cell housing is formed using high-frequency welding and laser welding processes. The cell housing has openings on both sides to facilitate welding to the cell cover. To reduce production costs and achieve lightweighting, the cell housing walls are often thinner. This results in lower strength in the cell housing, especially at the weld seams. When a battery experiences thermal runaway, the cell housing can easily rupture, leading to battery failure and a safety incident. Technical Solutions

[0004] In a first aspect, an embodiment of the present application provides a single cell battery, comprising a shell, the shell comprising at least one plate; a connecting portion connected to the plate, the connecting portion and the plate enclosing a receiving cavity; and a cladding layer, the cladding layer being provided on a side of the plate away from the receiving cavity, and the cladding layer covering the connecting portion.

[0005] Optionally, a cladding layer is provided on a side of the plate facing the accommodating cavity, and the cladding layer covers the connecting portion.

[0006] Optionally, two adjacent plates spaced apart from each other are arranged along a first direction; a dimension of the connecting portion along the first direction is a, a dimension of the cladding layer along the first direction is b, and the following conditions are satisfied: b≥a.

[0007] Optionally, the maximum dimension of the connecting portion along the first direction is a, satisfying: 0.3 mm ≤ a ≤ 1 mm.

[0008] Optionally, the minimum size of the cladding layer along the first direction is b, which satisfies: 0.5 mm ≤ b ≤ 1.5 mm.

[0009] Optionally, the maximum thickness of the cladding layer is c, the thickness of the plate is H, and the ratio of the maximum thickness of the cladding layer to the maximum thickness of the plate is x, satisfying: x=c / H, 0.1≤x≤2.

[0010] Optionally, the maximum thickness of the plate is H, satisfying: 0.3 mm ≤ H ≤ 2 mm.

[0011] Optionally, the thickness of the cladding layer is c, satisfying: 0.2 mm ≤ c ≤ 0.6 mm.

[0012] Optionally, the connecting portion includes a first protrusion, the first protrusion protrudes relative to the plate toward a side away from the accommodating cavity, and a protruding dimension of the first protrusion is d, satisfying: d≤0.05mm.

[0013] Optionally, the connecting portion further includes a second protrusion, which protrudes relative to the side of the plate facing the accommodating cavity. The protruding dimension of the second protrusion is e, and the maximum thickness of the cladding layer on the side facing the accommodating cavity is c, satisfying c>e.

[0014] Optionally, the protruding dimension of the second protrusion is e, satisfying: e≤0.15mm.

[0015] Optionally, the material of the cladding layer is at least one of titanium alloy, magnesium alloy and aluminum alloy.

[0016] Optionally, the dimension of the shell in the first direction is f, the dimension of the shell in the extension direction of the connecting part is g, and the dimension of the shell in the thickness direction of the connecting part is h, satisfying: 10mm≤f≤100mm, 100mm≤g≤600mm, 50mm≤h≤250mm.

[0017] Optionally, the dimension of the shell in the first direction is f, the dimension of the shell in the extension direction of the connecting part is g, and the dimension of the shell in the thickness direction of the connecting part is h, satisfying: 10mm≤f≤100mm, 600mm≤g≤1500mm, 50mm≤h≤250mm.

[0018] In a second aspect, the present application provides a method for preparing a single cell as described above, the method comprising: placing a covering material on the surface of the connecting portion; melting the covering material using a laser beam to form a cladding layer; wherein, during the laser cladding process, the scanning rate of the laser beam relative to the connecting portion is 50-500 mm / s; and during the laser cladding process, the laser power is 0.8-5 kW. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the following briefly introduces the drawings required for use in the description of the embodiments. Obviously, the drawings described below are only some embodiments of the present application. For those skilled in the art, other drawings can be obtained based on these drawings without creative work.

[0020] FIG1 is a schematic structural diagram of a housing according to an embodiment of the present application;

[0021] FIG2 is a schematic structural diagram of a housing according to another embodiment of the present application;

[0022] FIG3 is a cross-sectional view of a plate according to an embodiment of the present application;

[0023] FIG4 is a cross-sectional view of a plate according to another embodiment of the present application;

[0024] FIG5 is a cross-sectional view of a plate according to another embodiment of the present application. DETAILED DESCRIPTION

[0025] The following will be combined with the drawings in the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without making creative efforts are within the scope of protection of this application.

[0026] In blade lithium-ion batteries, the cell shell is formed using high-frequency welding and laser welding processes. The cell shell has openings on both sides to facilitate welding with the cell cover. In current blade lithium-ion batteries, to reduce production costs and achieve lightweighting goals, the cell shell walls are often thin. This results in lower strength in the cell shell, especially at the shell welds. When a battery experiences thermal runaway, the cell shell can easily rupture, leading to battery failure and a safety incident.

[0027] In view of this, an embodiment of the present application provides a single cell battery, comprising a housing, the housing comprising at least one plate, a connecting portion, and a cladding layer. The connecting portion is connected to the plate, and the connecting portion and the plate enclose a receiving cavity. The cladding layer is provided on the side of the plate away from the receiving cavity, and the cladding layer covers the connecting portion. With this arrangement, the cladding layer can strengthen the strength of the housing at the location of the connecting portion, improve the sealing of the housing, and thus prevent the housing from rupturing, causing the single cell battery to fail and causing a safety accident.

[0028] The method for preparing a single cell battery of an embodiment of the present application includes placing a covering material on the surface of the connecting portion. The covering material is melted by a laser beam to form a cladding layer. Particularly, the scanning rate of the laser beam relative to the connecting portion during the laser cladding process is 50-500 mm / s; the laser power during the laser cladding process is 0.8-5 kW. The laser cladding method is used to form a cladding layer, which can enhance the strength of the position where the connecting portion is located on the shell. In addition, the laser cladding method has a short action time and high energy density, so the stress and deformation generated on the shell are small. By controlling the scanning rate of the laser beam relative to the connecting portion and the laser power through the connecting portion, and strictly regulating the heat input, the formed cladding layer and the connecting portion can be firmly and reliably bonded.

[0029] The following describes the single cell and its preparation method in detail with reference to the accompanying drawings. Unless there is any conflict, the features of the following embodiments and implementations can be combined with each other.

[0030] With reference to Figures 1 to 4, an embodiment of the present application provides a single cell battery, comprising a shell 1, the shell 1 comprising at least one plate 10, a connecting portion 11 and a cladding layer 12. The connecting portion 11 is connected to the plate 10, and the connecting portion 11 and the plate 10 enclose a receiving cavity. The cladding layer 12, a cladding layer 12 is provided on the side of the plate 10 away from the receiving cavity, and the cladding layer 12 covers the connecting portion 11. In an embodiment of the present application, laser cladding technology is used to melt the covering material to form a cladding layer 12 to cover the connecting portion 11. In this manner, the cladding layer 12 can strengthen the strength of the position of the connecting portion 11 on the shell 1, improve the sealing of the shell 1, and thereby avoid rupture of the shell 1, resulting in failure of the single cell battery and causing a safety accident.

[0031] In the embodiment shown in Figure 4, a cladding layer 12 is provided on the side of the plate 10 facing the accommodating cavity, and the cladding layer 12 covers the connection portion 11. This arrangement strengthens the housing 1 at the location of the connection portion 11, improving the sealing of the housing 1 and thus preventing the housing 1 from rupturing, which could lead to single cell failure and safety accidents.

[0032] In the embodiment shown in Figure 2 , the plate 10 is connected to both sides of the connecting portion 11 along a first direction X. The maximum dimension of the connecting portion 11 along the first direction X is a, and the minimum dimension of the cladding layer 12 along the first direction X is b, satisfying the condition b ≥ a. That is, the maximum dimension of the connecting portion 11 along the first direction X is smaller than the minimum dimension of the cladding layer 12 along the first direction X. This arrangement ensures that the area of ​​the cladding layer 12 formed using laser cladding technology is larger than that of the connecting portion 11, thereby improving the sealing of the housing 1 and the strength of the connection portion 11.

[0033] In the embodiment shown in FIG2 , the maximum dimension of the connection portion 11 along the first direction X is a, satisfying the following: 0.3 mm ≤ a ≤ 1 mm. Specifically, the maximum dimension of the connection portion 11 along the first direction X can be any value selected from 0.3 mm, 0.4 mm, 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, or 1 mm, or a range between any two values. The minimum dimension of the cladding layer 12 along the first direction X is b, satisfying the following: 0.5 mm ≤ b ≤ 1.5 mm. Specifically, the minimum dimension of the cladding layer 12 along the first direction X can be any value selected from 0.5 mm, 0.6 mm, 0.7 mm, 0.8 mm, 0.9 mm, 1 mm, 1.1 mm, 1.2 mm, 1.3 mm, 1.4 mm, or 1.5 mm, or a range between any two values. This arrangement ensures that the area of ​​the cladding layer 12 formed using laser cladding technology is larger than that of the connection portion 11, thereby improving the sealing of the housing 1 and the strength of the connection portion 11.

[0034] In the embodiments shown in Figures 3 or 4 , the maximum thickness of the cladding layer 12 is c, the maximum thickness of the plate 10 is H, and the ratio of the maximum thickness of the cladding layer 12 to the maximum thickness of the plate 10 is x, satisfying: x = c / H, 0.1 ≤ x ≤ 2. The maximum thickness of the plate 10 is H, satisfying: 0.3 mm ≤ H ≤ 2 mm. The maximum thickness of the plate 10 can be any value of 0.3 mm, 0.6 mm, 0.9 mm, 1.2 mm, 1.5 mm, 1.8 mm, or 2 mm, or a range between any two values. The maximum thickness of the cladding layer 12 is c, satisfying: 0.2 mm ≤ c ≤ 0.6 mm. In some embodiments, the cladding layer 12 can be disposed on the side of the plate 10 away from the accommodating cavity and cover the connecting portion 11. Specifically, the maximum thickness of the cladding layer 12 can be any value of 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, or 0.6 mm, or a range between any two values. Controlling the thickness of the cladding layer 12 The maximum thickness of the cladding layer 12 is between 0.2 mm and 0.6 mm, which can improve the sealing of the shell 1 and the strength of the connection part 11 while controlling the action time of the laser cladding, so that the deformation of the shell 1 caused by processing stress is small.

[0035] In other embodiments, the cladding layer 12 can be provided on a side of the plate 10 near the accommodating cavity and cover the connection portion 11. Specifically, the maximum thickness of the cladding layer 12 can be any value selected from 0.2 mm, 0.3 mm, 0.4 mm, 0.5 mm, or 0.6 mm, or a range between any two values. Controlling the Thickness of the Cladding Layer 12 The maximum thickness of the cladding layer 12 is between 0.2 mm and 0.6 mm. This can improve the sealing performance of the housing 1 and the strength of the connection portion 11 while controlling the duration of the laser cladding, thereby minimizing deformation of the housing 1 due to processing stress.

[0036] In some embodiments, the thickness of the cladding layer 12 is controlled by setting appropriate laser cladding parameters, and the size of the cladding layer 12 in the thickness direction can be measured using an optical microscope.

[0037] In the embodiment shown in Figure 3, the connecting portion 11 includes a first protrusion 110, which protrudes relative to the plate 10 toward the side away from the accommodating cavity, and the protruding dimension of the first protrusion 110 is d, satisfying: d≤0.05mm. The thickness of the cladding layer 12 is greater than the protruding dimension of the first protrusion 110. Specifically, the protruding dimension of the first protrusion 110 can be any value of 0.01mm, 0.02mm, 0.03mm, 0.04mm or 0.05mm, or a range value between any two values. The connecting portion 11 connects adjacent plates 10 by welding, and the protruding dimension of the first protrusion 110 can be controlled by thinning the connecting portion 11, so that the cladding layer 12 can be subsequently covered on the connecting portion 11 by laser cladding technology.

[0038] In the embodiment shown in FIG4 , the connecting portion 11 further includes a second protruding portion 111, which protrudes relative to the side of the plate 10 facing the accommodating cavity. The protruding dimension of the second protruding portion 111 is e, and the maximum thickness of the cladding layer 12 on the side facing the accommodating cavity is c. The condition c>e is satisfied, meaning that the maximum thickness of the cladding layer 12 on the side facing the accommodating cavity is greater than the protruding dimension of the second protruding portion 111. This arrangement improves the sealing of the housing 1 and the strength of the connection portion 11.

[0039] In some embodiments, the protruding dimension of the second protrusion 111 is e, satisfying: e≤0.15mm. Specifically, the protruding dimension of the second protrusion 111 can be any value of 0.01mm, 0.02mm, 0.03mm, 0.04mm, 0.05mm, 0.06mm, 0.07mm, 0.08mm, 0.09mm, 0.1mm, 0.11mm, 0.12mm, 0.13mm, 0.14mm, or 0.15mm, or a range of values ​​between any two values. The connecting portion 11 connects adjacent plates 10 by welding. The protruding dimension of the second protrusion 111 can be controlled by thinning the connecting portion 11, so that the cladding layer 12 can be subsequently covered on the connecting portion 11 using laser cladding technology.

[0040] In the embodiment shown in FIG5 , the connection portion 11 includes a first protrusion 110 and a second protrusion 111. A cladding layer 12 is disposed on the surfaces of both the first protrusion 110 and the second protrusion 111. The thickness of the cladding layer 12 is greater than the protruding dimensions of the first and second protrusions 110, 111, thereby further improving the sealing properties of the housing 1 and the strength of the connection portion 11.

[0041] In some embodiments, the cladding layer 12 is made of at least one of a titanium alloy, a magnesium alloy, and an aluminum alloy. The cladding layer 12 is typically composed of a high-strength alloy material. The cladding layer 12 is metallurgically bonded to the housing 1, thereby increasing the strength of the housing 1, particularly at the connection portion 11.

[0042] In some embodiments, the dimension of the housing 1 in the first direction X is f, the dimension of the housing 1 in the extension direction of the connection portion 11 is g, and the dimension of the housing 1 in the thickness direction of the connection portion 11 is h. As shown in FIG1 , the following conditions are satisfied: 10 mm ≤ f ≤ 100 mm, 100 mm ≤ g ≤ 600 mm, and 50 mm ≤ h ≤ 250 mm. Specifically, the dimension of the housing 1 in the first direction X can be any value among 10 mm, 20 mm, 30 mm, 40 mm, 50 mm, 60 mm, 70 mm, 80 mm, 90 mm, or 100 mm, or a range between any two of them. The dimension of the housing 1 in the extension direction of the connection portion 11 can be any value among 100 mm, 200 mm, 300 mm, 400 mm, 500 mm, or 600 mm, or a range between any two of them. The dimension of the housing 1 in the thickness direction of the connection portion 11 can be any value among 50 mm, 100 mm, 150 mm, 200 mm, or 250 mm, or a range between any two of them.

[0043] In other embodiments, the dimension of the housing 1 in the extension direction of the connection portion 11 is g, satisfying the following: 600 mm ≤ g ≤ 1500 mm. Specifically, the dimension of the housing 1 in the extension direction of the connection portion 11 can be any value of 600 mm, 700 mm, 800 mm, 900 mm, 1000 mm, 1100 mm, 1200 mm, 1300 mm, 1400 mm, or 1500 mm, or a range of values ​​therebetween.

[0044] The present application provides a method for preparing a single cell battery as described above, comprising placing a covering material on the surface of the connecting portion 11. A laser beam is used to melt the covering material to form a cladding layer 12. At high temperatures, the covering material undergoes physical and chemical reactions on the connecting portion 11 and the surface of the plate 10 to form a mixture, which then cools and solidifies to ultimately form the cladding layer 12. During the laser cladding process, the laser beam scans the connecting portion 11 at a rate of 50-500 mm / s; the laser power during the laser cladding process is 0.8-5 kW. Forming the cladding layer 12 using the laser cladding method can strengthen the strength of the housing 1 at the location of the connecting portion 11, thereby enhancing the strength and sealing of the housing 1. Furthermore, the laser cladding method has a short action time and high energy density, resulting in less stress and deformation in the housing 1. By controlling the scanning rate and laser power of the laser beam across the connecting portion 11 and strictly regulating the heat input, the formed cladding layer 12 can be securely and reliably bonded to the connecting portion 11.

[0045] In some embodiments, the maximum thickness of the plate 10 is 0.5 mm. The comparative example is an unclad shell. The hardness of the cladding layer and the shell burst strength are shown in Table 1. The shell treated with laser cladding has improved hardness and compressive strength, both exceeding 1.3 MPa.

[0046] Table 1:

[0047] In some embodiments, the maximum thickness of the plate 10 is 1 mm. The comparative example is an unclad shell. The hardness of the cladding layer and the shell burst strength are shown in Table 2. The shell treated with laser cladding has improved hardness and compressive strength, both exceeding 1.3 MPa.

[0048] Table 2:

[0049] In some embodiments, the maximum thickness of the plate 10 is 2 mm. The comparative example is an unclad shell. The hardness of the cladding layer and the shell burst strength are shown in Table 3. The hardness and compressive strength of the shell after laser cladding are improved, with the compressive strength exceeding 1.3 MPa.

[0050] Table 3:

[0051] It can be seen that the shell provided by the embodiment of the present application after laser cladding has improved hardness and compressive strength compared with the shell without cladding, thereby preventing the shell from cracking, causing single cell failure, and causing safety accidents.

[0052] In the above embodiments, the description of each embodiment has its own focus. For parts that are not described in detail in a certain embodiment, reference can be made to the relevant descriptions of other embodiments.

[0053] The above is a detailed introduction to a single cell battery and its preparation method provided in the embodiments of the present application, and specific examples are used to illustrate the principles and implementation methods of the present application. The description of the above embodiments is only used to help understand the technical solution and core ideas of the present application; ordinary technicians in this field should understand that: they can still modify the technical solutions recorded in the aforementioned embodiments, or replace some of the technical features therein with equivalents; and these modifications or replacements do not cause the essence of the corresponding technical solution to deviate from the scope of the technical solution of the embodiments of the present application.

[0054] Reference numerals: 1, shell; 10, plate; 11, connecting portion; 12, cladding layer; 110, first protruding portion; 111, second protruding portion; X, first direction.

Claims

1. A single cell, comprising a housing (1), and the housing (1) includes: One or more plate members (10); A connecting portion (11) connected to the plate member (10), and an accommodation cavity is formed by enclosing the connecting portion (11) and the plate member (10); A cladding layer (12) is provided on one side of the plate member (10) away from and / or close to the accommodation cavity, and the cladding layer (12) covers the connecting portion (11).

2. The single cell according to claim 1, wherein, The cladding layer (12) covers the connecting portion (11).

3. The single cell according to claim 1 or 2, wherein, The plate member (10) is connected to both sides of the connecting portion (11) along a first direction (X); the maximum dimension of the connecting portion (11) along the first direction (X) is a, and the minimum dimension of the cladding layer (12) along the first direction (X) is b, satisfying: b≥a.

4. The single cell according to claim 3, wherein, The dimension of the connecting portion (11) along the first direction (X) is a, satisfying: 0.3mm≤a≤1mm.

5. The single cell according to claim 3 or 4, wherein, The dimension of the cladding layer (12) along the first direction (X) is b, satisfying: 0.5mm≤b≤1.5mm.

6. The single cell according to any one of claims 1-5, wherein, The maximum thickness of the cladding layer (12) is c, the maximum thickness of the plate member (10) is H, and the ratio of the maximum thickness of the cladding layer (12) to the maximum thickness of the plate member (10) is x, satisfying: x = c / H, 0.1≤x≤2.

7. The single cell according to claim 6, wherein, The thickness of the plate member (10) is H, satisfying: 0.3mm≤H≤2mm.

8. The single cell according to claim 6 or 7, wherein The maximum thickness of the cladding layer (12) is c, satisfying: 0.2mm≤c≤0.6mm.

9. The single cell according to any one of claims 1-8, wherein, The connecting portion (11) includes a first protruding portion (110), the first protruding portion (110) protrudes away from the accommodation cavity relative to the plate member (10), and the protruding dimension of the first protruding portion (110) is d, satisfying: d≤0.05mm.

10. The single cell according to any one of claims 1-9, wherein, The connecting portion (11) further includes a second protruding portion (111), the second protruding portion (111) protrudes toward the accommodation cavity relative to the plate member (10), the protruding dimension of the second protruding portion (111) is e, and the maximum thickness of the cladding layer (12) provided on the side facing the accommodation cavity is c, satisfying c>e.

11. The single cell according to any one of claims 1-10, wherein, The connecting portion (11) further includes a second protruding portion (111), the second protruding portion (111) protrudes toward the accommodation cavity relative to the plate member (10), the protruding dimension of the second protruding portion (111) is e, satisfying: e≤0.15mm.

12. The single cell according to any one of claims 1-11, wherein, The material of the cladding layer (12) is at least one of titanium alloy, magnesium alloy, and aluminum alloy.

13. The single cell according to any one of claims 1 to 12, wherein, The dimension of the housing (1) in the first direction (X) is f, the dimension of the housing (1) in the extending direction of the connecting portion (11) is g, and the dimension of the housing (1) in the thickness direction of the connecting portion (11) is h, satisfying: 10mm≤f≤100mm, 100mm≤g≤600mm, 50mm≤h≤250mm.

14. The single cell according to any one of claims 1-13, wherein, The size of the housing (1) in the first direction (X) is f, the size of the housing (1) in the extending direction of the connecting portion (11) is g, and the size of the housing (1) in the thickness direction of the connecting portion (11) is h, satisfying: 10 mm ≤ f ≤ 100 mm, 600 mm ≤ g ≤ 1500 mm, 50 mm ≤ h ≤ 250 mm.

15. A method for preparing a single cell as described in any one of claims 1-14, wherein, Including: Placing the covering material on the surface of the connecting portion (11); Melting the covering material by a laser beam to form a cladding layer (12); Wherein, during the laser cladding process, the scanning rate of the laser beam relative to the connecting portion (11) is 50 - 500 mm / s; and the laser power during the laser cladding process is 0.8 - 5 kW.

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