A cylindrical lithium battery

Abstract

The utility model relates to the technical field of cylindrical battery, put forward a kind of cylindrical lithium battery, including shell cylinder, roll core, negative cover plate and negative current collector plate;The negative cover plate is fixedly arranged at one end of the shell cylinder, the side of the negative cover plate is provided with annular protrusion;The two ends of the negative current collector plate are respectively welded and fixed on the protrusion and the negative tab;The distance between the negative tab and the negative cover plate away from the roll core side is H 50 , the height of the negative current collector plate along the shell cylinder axis is H 51 , H 51 / H 50 =64.7% to 76.5%.The utility model sets up protrusion on negative cover plate, not only can be convenient to the welding of negative current collector plate and negative cover plate, can also promote the structural strength of negative cover plate, by limiting the height of negative current collector plate after bending, not only can avoid negative current collector plate extrusion roll core, can also guarantee the structural strength of negative cover plate and the energy density of battery, to effectively improve the overall performance of battery.

Description

Technical Field

[0001] This utility model relates to the field of cylindrical battery technology, and in particular to a cylindrical lithium battery. Background Technology

[0002] Cylindrical lithium batteries are lithium batteries encapsulated in a cylindrical casing. They store and release electrical energy by moving lithium ions between the positive and negative electrodes, and are widely used in consumer electronics, electric vehicles, and energy storage.

[0003] Cylindrical lithium batteries are mainly composed of a casing, a core, and positive and negative current collectors. The positive and negative current collectors are welded and fixed to the positive and negative tabs of the core using methods such as laser welding and ultrasonic welding, respectively, to collect and conduct current.

[0004] For example, the utility model disclosed in CN214625311U discloses a multi-tab cylindrical battery with a current collector, which has a current collector between the cover plate and the tabs, and a first bend and a second bend on the current collector. The bend of the current collector is used to connect the cover plate and the tabs and to install the cover plate into the casing. However, this technical solution does not limit the height of the current collector after folding. If the height is too small, the installation space of the current collector is limited, and the current collector will squeeze the core during the bending process, making the battery prone to short circuit. If the height is too large, the current collector occupies a large space, which will reduce the battery capacity and energy density. Utility Model Content

[0005] In view of this, this utility model proposes a cylindrical lithium battery. By reasonably setting the height of the negative electrode current collector after bending, the structural strength, safety performance and energy density of the battery can be taken into account, effectively improving the overall performance of the battery.

[0006] The technical solution of this utility model is implemented as follows: This utility model provides a cylindrical lithium battery, including a casing, a core, a negative electrode cover plate, and a negative electrode current collector. The core is disposed inside the casing, with a negative electrode tab at one end. The negative electrode cover plate is fixedly disposed at one end of the casing, and an annular protrusion is provided on one side of the negative electrode cover plate. The negative electrode current collector is bent into an S-shape, and its two ends are welded and fixed to the protrusion and the negative electrode tab, respectively. The distance between the negative electrode tab and the side of the negative electrode cover plate away from the core is H. 50 The height of the negative electrode current collector along the axial direction of the shell is H. 51 H 51 / H 50 =64.7% - 76.5%.

[0007] Based on the above technical solution, preferably, the negative electrode cover plate has a groove on the side away from the protrusion, and the protrusion is formed by stamping the groove on the negative electrode cover plate; the depth of the groove is H. 52 H 52 / H 50 =8.8% - 14.7%.

[0008] Based on the above technical solution, preferably, the negative electrode current collector is provided with a first bending line and a second bending line. The negative electrode current collector is bent at the first bending line to form a plate body end, which is welded and fixed to the negative electrode lug. The negative electrode current collector is bent at the second bending line to form a tail end, which is welded and fixed to the negative electrode cover plate. The length of the plate body end is L. 61 L 61 =35.49mm-39.49mm.

[0009] More preferably, the distance between the end of the tail body furthest from the second bend line and the first bend line is L. 62 L 62 =2.46mm-3.46mm.

[0010] More preferably, the distance between the end of the disc body furthest from the first bending line and the second bending line is L. 64 L 64 / L 61 =25.1% - 30.4%.

[0011] More preferably, the diameter of the shell is D. 10 The distance between the second bending line and the inner wall of the shell is L. 12 L 12 / D 10 =23.8% - 28.2%.

[0012] More preferably, the distance between the first bending line and the inner wall of the shell is L. 13 L 13 / D 10 =14% - 16.2%.

[0013] More preferably, the end of the tail body furthest from the second bending line is welded and fixed to the protrusion; the distance between the end of the tail body furthest from the second bending line and the outer edge of the protrusion is W. 15 W 15 =0.55mm-0.95mm.

[0014] More preferably, the end of the tailstock near the second bend line is located within the protrusion; the distance between the end of the tailstock near the second bend line and the protrusion is L. 65 L 65 = 1.81mm - 2.41mm.

[0015] Based on the above technical solutions, preferably, the diameter of the shell is D. 10 D 10 =44mm-48mm, H 50 =3.2mm-3.6mm.

[0016] The cylindrical lithium battery of this invention has the following advantages over the prior art:

[0017] (1) By setting protrusions on the negative electrode cover plate, it is not only convenient to weld the negative electrode current collector and the negative electrode cover plate, but also to improve the structural strength of the negative electrode cover plate. By limiting the height of the negative electrode current collector after bending, it is not only possible to prevent the negative electrode current collector from squeezing the core, but also to ensure the structural strength of the negative electrode cover plate and the energy density of the battery, thereby effectively improving the overall performance of the battery.

[0018] (2) By further limiting the specifications and installation position of the negative electrode current collector, the assembly efficiency and current carrying capacity of the battery can be further improved, thereby further improving the overall performance of the battery. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this utility model 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 utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a cross-sectional view of a cylindrical lithium battery according to the present invention.

[0021] Figure 2 This is a cross-sectional view of the first bend line in a cylindrical lithium battery according to the present invention.

[0022] Figure 3 This is a cross-sectional view of the second bend line in a cylindrical lithium battery according to the present invention.

[0023] Figure 4 This is a perspective view of a cylindrical lithium battery according to the present invention.

[0024] Among them: 1. Shell; 2. Core; 21. Negative electrode tab; 3. Negative electrode cover plate; 31. Protrusion; 301. Groove; 4. Negative electrode current collector; 41. Plate end; 42. Tail end; 401. First bending line; 402. Second bending line. Detailed Implementation

[0025] The technical solutions of this utility model will be clearly and completely described below with reference to specific embodiments. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this utility model.

[0026] The present invention relates to a cylindrical lithium battery, comprising a casing 1, a core 2, a negative electrode cover plate 3, and a negative electrode current collector 4.

[0027] The shell 1 is a cylindrical structure with openings at both the positive and negative ends. The core 2 is placed inside the shell 1, and positive and negative electrode tabs 21 are respectively provided at both ends of the core 2. The negative electrode current collector 4 is welded and fixed between the negative electrode tab 21 and the negative electrode cover plate 3. The negative electrode cover plate 3 is fixedly placed on the shell 1 and blocks the opening at the negative end of the shell 1, thereby achieving the sealing of the negative end of the shell 1 and the conduction between the negative electrode tab 21 and the negative electrode cover plate 3.

[0028] The negative electrode current collector 4 has a long strip structure. First, one end of the negative electrode current collector 4 is welded and fixed to the negative electrode tab 21. Then, the other end of the negative electrode current collector 4 is welded and fixed to the negative electrode cover plate 3. Finally, by bending the negative electrode current collector 4, the negative electrode current collector 4 is formed into an S-shape, so that the negative electrode cover plate 3 can be fixedly installed on the negative terminal of the shell 1 to realize the assembly of the battery.

[0029] When assembling the battery using the above process, the welding convenience between the negative electrode current collector 4 and related components can be improved, thereby effectively improving the assembly quality and efficiency of the battery.

[0030] like Figures 1-3 As shown, a protrusion 31 is provided on the side of the negative electrode cover plate 3 near the core 2. The protrusion 31 is a ring structure. The end of the negative electrode current collector 4 away from the negative electrode tab 21 is welded and fixed to the side of the protrusion 31 near the core 2.

[0031] The negative electrode cover plate 3 is a circular plate structure. A groove 301 is provided on the side of the negative electrode cover plate 3 away from the protrusion 31. By stamping the groove 301, the protrusion 31 can be formed on the other side of the negative electrode cover plate 3. The groove 301 is also a ring structure.

[0032] like Figure 2As shown, in order to facilitate the stamping of the groove 301 and improve the processing quality and efficiency of the protrusion 31, it is preferable to set the cross-section of the groove 301 to be an isosceles trapezoid.

[0033] like Figures 1-3 As shown, the negative electrode current collector 4 is provided with a first bending line 401 and a second bending line 402. The originally straight negative electrode current collector 4 is bent at the first bending line 401 to form a plate end 41. The plate end 41 is welded and fixed to the negative electrode tab 21. The negative electrode current collector 4 is bent at the second bending line 402 to form a tail end 42. The tail end 42 is welded and fixed to the negative electrode cover plate 3.

[0034] When welding the negative electrode current collector 4 and the negative electrode tab 21, the entire disc end 41 is in contact with the negative electrode tab 21, and the disc end 41 is welded and fixed to the negative electrode tab 21; when welding the negative electrode current collector 4 and the negative electrode cover plate 3, the end of the tail end 42 away from the negative electrode current collector 4 is welded and fixed to the bottom side of the protrusion 31.

[0035] like Figures 1-3 As shown, since the tail end 42 is welded and fixed to the protrusion 31, one side of the tail end 42 is flush with one side of the protrusion 31; in order to avoid the tail end 42 interfering with the inner wall of the shell 1 during the assembly process, it is preferable to place the second bending line 402 inside the annular protrusion 31.

[0036] like Figures 1-2 As shown, the diameter of shell 1 is D. 10 The distance between the negative electrode tab 21 and the negative electrode cover plate 3 on the side away from the core 2 is H. 50 The height of the negative electrode current collector 4 along the axial direction of the shell cylinder 1 is H. 51 That is, the distance between the protrusion 31 and the negative electrode tab 21 is H. 51 The depth of groove 301 is H. 52 .

[0037] In some embodiments, D 10 =44mm-48mm, that is, the diameter of shell 1 is 44mm, 46mm or 48mm, etc.

[0038] In some embodiments, H 50 =3.2mm-3.6mm, that is, the distance between the negative electrode tab 21 and the negative electrode cover plate 3 on the side away from the core 2 is 3.2mm, 3.4mm or 3.6mm, etc.

[0039] In some embodiments, H 51 / H 50 =64.7%-76.5%, meaning the height of the negative electrode current collector 4 along the axial direction of the shell cylinder 1 is 64.7%, 70.6%, or 76.5% of the distance between the negative electrode lug 21 and the negative electrode cover plate 3 on the side away from the core 2, etc. If H51 / H 50 If the height of the negative electrode current collector 4 along the axial direction of the shell cylinder 1 is less than 64.7%, then the distance between the protrusion 31 and the negative electrode tab 21 is too small, resulting in limited installation space for the negative electrode current collector 4. During the bending process of the negative electrode current collector 4, it will compress the core 2, making the battery prone to short circuits. If H 51 / H 50 If the height of the negative electrode current collector 4 along the axial direction of the shell cylinder 1 is greater than 76.5%, then the distance between the protrusion 31 and the negative electrode tab 21 is too large. On the one hand, the excessive distance between the protrusion 31 and the negative electrode tab 21 will cause the negative electrode current collector 4 to occupy a large space, resulting in a decrease in both the battery capacity and energy density. On the other hand, if the height of the negative electrode current collector 4 along the axial direction of the shell cylinder 1 is too large, the height of the corresponding protrusion 31 will be reduced. This will not only reduce the structural strength of the negative electrode cover plate 3, making the negative electrode cover plate 3 prone to deformation, but will also affect the welding effect between the protrusion 31 and the negative electrode current collector 4.

[0040] In some embodiments, H 52 / H 50 =8.8%-14.7%, meaning the depth of groove 301 is 8.8%, 11.8%, or 14.7% of the distance between the negative electrode tab 21 and the negative electrode cover plate 3 on the side away from the core 2, etc. If H 52 / H 50 If the depth of the groove 301 is less than 8.8%, the corresponding height of the protrusion 31 will be reduced. This will not only reduce the structural strength of the negative electrode cover plate 3, making it prone to deformation, but also affect the welding effect between the protrusion 31 and the negative electrode current collector 4. 52 / H 50 If the depth of the groove 301 is greater than 14.7%, it will occupy the internal space of the shell 1, resulting in a smaller installation space after the negative electrode current collector 4 is bent. During the bending and insertion of the negative electrode current collector 4 into the shell, the insufficient installation space will cause the negative electrode current collector 4 to squeeze the end of the core 2, making the battery prone to short circuit.

[0041] like Figures 1-3 As shown, the length of end 41 of the disk is L. 61 The distance between the end of the tail section 42 furthest from the second bend line 402 and the first bend line 401 is L. 62 The distance between the end of the disk body 41 furthest from the first bend line 401 and the second bend line 402 is L. 64 The distance between the second bending line 402 and the inner wall of the shell 1 is L. 12 The distance between the first bending line 401 and the inner wall of the shell 1 is L. 13 The distance between the end of the tail section 42 near the second bend line 402 and the protrusion 31 is L. 65The distance between the end of the tail section 42 furthest from the second bend line 402 and the outer edge of the protrusion 31 is W. 15 .

[0042] In some embodiments, L 61 =35.49mm-39.49mm, meaning the length of end 41 of the disk is 35.49mm, 37.49mm, or 39.49mm, etc. If L 61 If the length is less than 35.49mm, the length of the disc end 41 is too small, meaning the welding area between the disc end 41 and the negative electrode tab 21 is reduced, leading to increased temperature rise at the welding point and affecting battery performance; if L 61 If the length of the disc end 41 is greater than 39.49mm, it will interfere with the inner wall of the shell 1 during battery assembly, affecting the assembly quality and efficiency of the battery.

[0043] In some embodiments, L 62 = 2.46mm-3.46mm, meaning the distance between the end of the tail body 42 furthest from the second bending line 402 and the first bending line 401 is 2.46mm, 2.96mm, or 3.46mm, etc. If the welding position of the tail body end 42 remains unchanged, and L... 62 If the distance between the end of the tail body 42 furthest from the second bending line 402 and the first bending line 401 is too small, that is, the length of the disc end 41 is too large. During battery assembly, the disc end 41 will interfere with the inner wall of the shell 1, affecting the assembly quality and efficiency of the battery. 62 If the distance between the end of the tail body 42 away from the second bending line 402 and the first bending line 401 is too large, that is, the length of the disc end 41 is too small. The welding area between the disc end 41 and the negative electrode tab 21 is reduced, and the temperature rise at the welding position is increased, which will affect the performance of the battery.

[0044] In some embodiments, L 64 / L 61 =25.1%-30.4%, meaning the distance between the end of the disc 41 furthest from the first bend line 401 and the second bend line 402 is 25.1%, 27.8%, or 30.4% of the length of the disc end 41, etc. If L 64 / L 61 If the distance between the end of the disk body 41 furthest from the first bending line 401 and the second bending line 402 is too small, the overall length of the negative electrode current collector 4 will increase while ensuring that the welding area between the disk body end 41 and the negative electrode tab 21 and the welding position of the tail end 42 remain unchanged. This will not only increase the weight and manufacturing cost of the battery, but also affect the energy density of the battery. If L 64 / L 61If the distance between the end of the disc body 41 furthest from the first bending line 401 and the second bending line 402 is too large, the overall length of the negative electrode current collector 4 will be shortened if the welding area between the disc body end 41 and the negative electrode tab 21 and the welding position of the tail end 42 remain unchanged. This will cause the negative electrode cover plate 3 to be too close to the end of the shell cylinder 1 when welding with the negative electrode current collector 4, affecting the welding quality between the negative electrode cover plate 3 and the negative electrode current collector 4, and reducing the production quality and efficiency of the battery.

[0045] Furthermore, L 64 / D 10 =20.5%-24.8%, that is, the distance between the end of the disk 41 away from the first bending line 401 and the second bending line 402 is 20.5%, 22.6% or 24.8% of the diameter of the shell 1, etc., so as to take into account both the energy density of the battery and the assembly quality.

[0046] In some embodiments, L 12 / D 10 =23.8%-28.2%, meaning the distance between the second bending line 402 and the inner wall of the shell 1 is 23.8%, 26%, or 28.2% of the diameter of the shell 1, etc. If L 12 / D 10 If the distance between the second bending line 402 and the inner wall of the shell 1 is less than 23.8%, the overall length of the negative electrode current collector 4 will increase, which will not only increase the weight and manufacturing cost of the battery, but also affect the energy density of the battery; if L 12 / D 10 If the distance between the second bending line 402 and the inner wall of the shell 1 is too large, the overall length of the negative electrode current collector 4 will be shortened, resulting in the negative electrode cover plate 3 being too close to the end of the shell 1 when welding with the negative electrode current collector 4, which will affect the welding quality of the negative electrode cover plate 3 and the negative electrode current collector 4, and reduce the production quality and efficiency of the battery.

[0047] In some embodiments, L 13 / D 10 =14%-16.2%, meaning the distance between the first bending line 401 and the inner wall of the shell 1 is 14%, 15.1%, or 16.2% of the diameter of the shell 1, etc. If L 13 / D 10 If the distance is less than 14%, then the distance between the first bending line 401 and the inner wall of the casing 1 is too small. When the negative electrode current collector 4 is bent into the casing, the negative electrode current collector 4 is prone to interference with the inner wall of the casing 1, affecting the assembly of the battery; if L 13 / D 10 If the value is greater than 16.2%, the distance between the first bending line 401 and the inner wall of the shell 1 is too large, the welding area between the disc end 41 and the negative electrode tab 21 is reduced, resulting in a weakening of the current carrying capacity at the welding position, an increase in temperature, and an impact on the battery performance.

[0048] In some embodiments, W 15 =0.55mm-0.95mm, meaning the distance between the end of the tail section 42 furthest from the second bending line 402 and the outer edge of the protrusion 31 is 0.55mm, 0.75mm, or 0.95mm, etc. If W 15 If the distance between the end of the tail end 42 furthest from the second bending line 402 and the outer edge of the protrusion 31 is too small, on the one hand, the overall length of the negative electrode current collector 4 will increase, which will not only increase the weight and manufacturing cost of the battery, but also affect the energy density of the battery. On the other hand, if the tail end 42 is too close to the edge of the protrusion 31, welding defects such as incomplete soldering are likely to occur between the end of the tail end 42 and the protrusion 31. If W 15 If the distance is greater than 0.95mm, the distance between the end of the tail body 42 away from the second bending line 402 and the outer edge of the protrusion 31 is too large. The welding area between the tail body 42 and the protrusion 31 is reduced, which weakens the current carrying capacity at the welding position, increases the temperature, and affects the performance of the battery.

[0049] In some embodiments, L 65 =1.81mm-2.41mm, meaning the distance between the end of the tail section 42 near the second bend line 402 and the protrusion 31 is 1.81mm, 2.11mm, or 2.41mm, etc. If L 65 If the distance between the tail end 42 near the second bend line 402 and the protrusion 31 is too small, the overall length of the negative electrode current collector 4 will increase, which will not only increase the weight and manufacturing cost of the battery, but also affect the energy density of the battery; if L 65 If the distance is greater than 2.41mm, the distance between the end of the tail body 42 near the second bending line 402 and the protrusion 31 will be too large, and the overall length of the negative electrode current collector 4 will be shortened. This will cause the negative electrode cover plate 3 to be too close to the end of the shell cylinder 1 when it is welded to the negative electrode current collector 4, which will affect the welding quality of the negative electrode cover plate 3 and the negative electrode current collector 4, and reduce the production quality and production efficiency of the battery.

[0050] Furthermore, the groove 301 and the protrusion 31 are preferably annular structures, and the center of both coincides with the center of the negative electrode cover plate 3.

[0051] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A cylindrical lithium battery, characterized in that: It includes a shell (1), a core (2), a negative electrode cover plate (3), and a negative electrode current collector (4), wherein, The core (2) is disposed inside the shell (1), and a negative electrode tab (21) is provided at one end; The negative electrode cover plate (3) is fixedly disposed at one end of the shell (1), and an annular protrusion (31) is provided on one side of the negative electrode cover plate (3); The negative electrode current collector (4) is bent into an S-shape, and the two ends of the negative electrode current collector (4) are welded and fixed to the protrusion (31) and the negative electrode tab (21) respectively. The distance between the negative electrode tab (21) and the negative electrode cover plate (3) on the side away from the core (2) is H. 50 The height of the negative electrode current collector (4) along the axial direction of the shell (1) is H. 51 H 51 / H 50 =64.7% - 76.5%.

2. A cylindrical lithium battery as described in claim 1, characterized in that: The negative electrode cover plate (3) has a groove (301) on the side away from the protrusion (31), and the protrusion (31) is formed by stamping the groove (301) on the negative electrode cover plate (3); The depth of the groove (301) is H. 52 H 52 / H 50 =8.8% - 14.7%.

3. A cylindrical lithium battery as described in claim 1, characterized in that: The negative electrode current collector (4) is provided with a first bending line (401) and a second bending line (402). The negative electrode current collector (4) is bent at the first bending line (401) to form a disk body end (41). The disk body end (41) is welded and fixed to the negative electrode tab (21). The negative electrode current collector (4) is bent at the second bending line (402) to form a tail body end (42). The tail body end (42) is welded and fixed to the negative electrode cover plate (3). The length of the disk end (41) is L 61 L 61 =35.49mm-39.49mm.

4. A cylindrical lithium battery as described in claim 3, characterized in that: The distance between the end of the tail section (42) away from the second bend line (402) and the first bend line (401) is L. 62 L 62 =2.46mm-3.46mm.

5. A cylindrical lithium battery as described in claim 4, characterized in that: The distance between the end of the disc body (41) furthest from the first bending line (401) and the second bending line (402) is L. 64 L 64 / L 61 =25.1% - 30.4%.

6. A cylindrical lithium battery as described in claim 3, characterized in that: The diameter of the shell (1) is D 10 The distance between the second bending line (402) and the inner wall of the shell (1) is L. 12 L 12 / D 10 =23.8% - 28.2%.

7. A cylindrical lithium battery as described in claim 6, characterized in that: The distance between the first bending line (401) and the inner wall of the shell (1) is L. 13 L 13 / D 10 =14% - 16.2%.

8. A cylindrical lithium battery as described in claim 3, characterized in that: The tail end (42) away from the second bending line (402) is welded and fixed to the protrusion (31); The distance between the end of the tail (42) away from the second bending line (402) and the outer edge of the protrusion (31) is W. 15 W 15 =0.55mm-0.95mm.

9. A cylindrical lithium battery as described in claim 8, characterized in that: The tail end (42) near the second bend line (402) is located inside the protrusion (31); The distance between the end of the tail section (42) near the second bend line (402) and the protrusion (31) is L. 65 L 65 =1.81mm-2.41mm.

10. A cylindrical lithium battery as described in any one of claims 1-9, characterized in that: The diameter of the shell (1) is D 10 D 10 =44mm-48mm, H 50 =3.2mm-3.6mm.

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