A lithium-ion cylindrical battery

Abstract

The utility model relates to cylindrical battery technical field, proposes a kind of lithium ion cylindrical battery, including shell, positive pole, roll core, positive pole lug and positive current collector, the positive pole lug with the roll core is connected, and the one end of the positive pole lug protrudes the end of the roll core;The positive current collector is fixedly arranged on the positive pole lug;The middle part of the positive current collector near the positive pole lug side is provided with isolation groove, so that the side of the positive current collector away from the positive pole lug forms connecting boss, the connecting boss with the positive pole fixed connection;The spacing of the roll core near the one end of the positive pole with the shell is H 20 , the depth of the isolation groove is H 22 , H 22 / H 20 =21%‑31. 6%.The utility model sets up isolation groove and connecting boss on the positive current collector, and the depth of the isolation groove is reasonably limited, not only can improve the safety performance of battery, but also can reduce the processing difficulty 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 lithium-ion cylindrical battery. Background Technology

[0002] A lithium-ion cylindrical battery is a lithium-ion battery encapsulated in a cylindrical shell. It consists of components such as a positive electrode, a negative electrode, an electrolyte, a separator, and a shell. It stores and releases electrical energy by moving lithium ions between the positive and negative electrodes and has been widely used in consumer electronics, electric vehicles, and energy storage.

[0003] To reduce the internal resistance of a battery and improve its overall performance, a positive current collector is typically welded between the positive electrode tab and the cap assembly of the battery core to optimize the current path and structural stability. For example, a cylindrical battery positive electrode cap assembly disclosed in invention patent CN119764698A has a positive electrode post on the substrate and a positive current collector between the positive electrode post and the battery cell, thereby achieving conductivity between the battery cell and the positive electrode post.

[0004] The positive current collector and the positive terminal are usually fixed by laser welding. In the above technical solution, the position on the positive current collector that is welded to the positive terminal is directly attached to the cell. The high temperature generated when the positive current collector and the positive terminal are welded can burn the separator inside the cell, which increases the risk of short circuit in the battery. Utility Model Content

[0005] In view of this, this utility model proposes a cylindrical lithium-ion battery, which achieves a balance between battery safety and production yield by reasonably limiting the depth of the isolation groove, thereby 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 lithium-ion cylindrical battery, including a casing, a positive electrode post, a winding core, a positive electrode tab, and a positive current collector. The positive electrode post is disposed at the end of the casing, and the two are sealed and insulated. The winding core is disposed inside the casing. The positive electrode tab is connected to the winding core, and one end of the positive electrode tab extends beyond the end of the winding core. The positive current collector is fixedly disposed on the positive electrode tab. An isolation groove is provided in the middle of the positive current collector near the positive electrode tab, and a connecting boss is formed on the side of the positive current collector away from the positive electrode tab. The connecting boss is fixedly connected to the positive electrode post. The distance between the end of the winding core near the positive electrode post and the casing is H. 20 The depth of the isolation groove is H. 22 H 22 / H 20 =21%-31.6%.

[0007] Based on the above technical solution, preferably, the distance between the positive current collector and the positive electrode post is H. 23 H 23 / H 20 =21%-31.6%.

[0008] Based on the above technical solutions, preferably, the thickness of the positive electrode current collector is H. 21 H 21 / H 20 =7.9%-13.2%.

[0009] Based on the above technical solutions, preferably, the overall height of the positive electrode tab is H. 24 H 24 / H 20 =15.8%-26.3%.

[0010] Based on the above technical solutions, preferably, the distance between the isolation groove and the periphery of the positive electrode current collector is W. 21 W 21 =13.91mm-15.91mm.

[0011] Based on the above technical solution, preferably, the connecting boss has an injection hole, and the distance between the injection hole and the periphery of the connecting boss is W. 22 W 22 =3.35mm-4.35mm.

[0012] Based on the above technical solutions, preferably, the periphery of the connecting boss is conical; the angle between the periphery of the connecting boss and the positive current collector is B, where B = 118°-138°.

[0013] Based on the above technical solutions, preferably, the distance between the periphery of the positive current collector and the inner wall of the housing is W. 23 W 23 =1.05mm-1.65mm.

[0014] Based on the above technical solution, preferably, it also includes an injection pin, wherein the positive electrode post has an assembly hole, the injection pin is fixedly disposed in the assembly hole, and located within the injection hole; the distance between the periphery of the injection pin and the inner wall of the injection hole is W. 24 W 24 =0.36mm-0.76mm.

[0015] Based on the above technical solutions, the preferred option is H. 20 =3.3mm-4.3mm.

[0016] The lithium-ion cylindrical battery of this invention has the following advantages over the prior art: (1) By setting an isolation groove and a connecting boss on the positive electrode current collector and reasonably limiting the depth of the isolation groove, the safety performance of the battery can be improved, and the processing difficulty of the battery can be reduced, thereby effectively improving the overall performance of the battery.

[0017] (2) By reasonably limiting the specifications of the positive electrode current collector, isolation groove, connecting boss and liquid injection hole, not only can the safety performance of the battery be further improved and the processing difficulty of the battery be reduced, but also the energy density of the battery and the structural reliability of the welding position can be improved. Attached Figure Description

[0018] 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.

[0019] Figure 1 This is a cross-sectional view of a lithium-ion cylindrical battery according to the present invention.

[0020] Figure 2 This is a cross-sectional view of the connecting boss in a lithium-ion cylindrical battery according to the present invention.

[0021] Figure 3 This is a cross-sectional view of the positive electrode current collector in a lithium-ion cylindrical battery according to this utility model.

[0022] Figure 4 This is a cross-sectional view of the liquid injection pin in a lithium-ion cylindrical battery according to the present invention.

[0023] The components are: 1. Shell; 2. Positive electrode post; 201. Assembly hole; 3. Core; 4. Positive electrode tab; 5. Positive electrode current collector; 501. Isolation groove; 502. Connecting boss; 503. Liquid injection hole; 6. Liquid injection pin. Detailed Implementation

[0024] 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.

[0025] This utility model discloses a lithium-ion cylindrical battery, comprising a casing 1, a positive electrode post 2, a core 3, a positive electrode tab 4, a negative electrode tab, a positive current collector 5, a negative current collector, and an injection pin 6.

[0026] The housing 1 is a cylindrical structure with an internal cavity. The two ends of the housing 1 are the positive end and the negative end, respectively. The positive end of the housing has a mounting hole, and the positive terminal 2 is placed in the mounting hole. One end of the positive terminal 2 is located inside the housing 1, and the other end of the positive terminal 2 is located outside the housing 1. Plastic parts and sealing rings are provided between the positive terminal 2 and the housing 1, so that the positive terminal 2 and the housing 1 are sealed and insulated.

[0027] The core 3 is disposed inside the housing 1. The two ends of the core 3 are the positive end and the negative end, respectively. The positive electrode tab 4 is connected to the positive end of the core, and the negative electrode tab is connected to the negative end of the core. Both the positive electrode tab 4 and the negative electrode tab are full-tab structures. One end of the positive electrode tab 4 extends out of the positive end of the core, and one end of the negative electrode tab extends out of the negative end of the core. After the positive electrode tab 4 and the negative electrode tab are subsequently flattened, the positive current collector 5 is fixedly disposed between the positive electrode tab 4 and the positive electrode post 2, and the negative current collector is fixedly disposed between the negative electrode tab and the negative end of the housing, so that the positive end and the negative end of the core are connected to the positive electrode post 2 and the negative end of the housing, respectively.

[0028] The core 3 is made of positive electrode sheet, separator and negative electrode sheet stacked and wound, which makes the thickness of the middle part of the positive electrode tab 4 relatively thin. When welding the positive electrode post 2 and the positive electrode current collector 5, the welding heat will be transferred to the core 3, burn the separator in the core 3, and cause the core 3 to short circuit.

[0029] To solve the above problems, an isolation groove 501 is punched out in the middle of the positive current collector 5 on the side near the positive electrode tab 4, causing the positive current collector 5 to deform, that is, a connecting boss 502 is formed on the side of the positive current collector 5 away from the positive electrode tab 4; such as Figure 2 As shown, the bottom side of the positive current collector 5 is welded and fixed to the positive electrode tab 4, and the top side of the connecting boss 502 is welded and fixed to the positive electrode post 2; as Figure 1 and Figure 2 As shown, the isolation groove 501 is designed so that the welding position of the connecting boss 502 and the positive electrode tab 4 is far away from the positive electrode tab 4 and the core 3, which can avoid the welding heat of the connecting boss 502 and the positive electrode tab 4 from damaging the separator and effectively reduce the risk of short circuit of the battery.

[0030] like Figure 1 As shown, the isolation groove 501 has a tapered structure that is narrow at the top and wide at the bottom, which can effectively reduce the machining difficulty of the isolation groove 501 and the connecting boss 502 and improve the machining efficiency of the positive electrode current collector 5.

[0031] like Figure 1and Figure 4 As shown, the core 3 has a central hole in the middle, the positive electrode post 2 has an assembly hole 201, and the connecting boss 502 has an injection hole 503. After the battery completes the assembly of the positive electrode post 2, electrolyte can be added into the central hole through the assembly hole 201 and the injection hole 503. After the injection operation is completed, the injection pin 6 is fixed in the assembly hole 201 to achieve battery encapsulation and avoid problems such as electrolyte leakage.

[0032] like Figure 1 As shown, it is preferable to insert the injection pin 6 into the injection hole 503 and the center hole.

[0033] To improve the symmetry and stability of the battery, it is preferable that the positive electrode post 2, the mounting hole 201, the core 3, the positive electrode current collector 5, the connecting boss 502, and the liquid injection hole 503 are all coaxially arranged with the housing 1.

[0034] like Figures 1-4 As shown, the distance between the end of the core 3 near the positive electrode post 2 and the shell 1 is H. 20 The thickness of the positive current collector 5 is H. 21 The depth of isolation groove 501 is H 22 The distance between the positive current collector 5 and the positive terminal 2 is H. 23 The overall height of the positive electrode tab 4 is H. 24 The distance between the isolation groove 501 and the periphery of the positive current collector 5 is W. 21 The distance between the injection hole 503 and the periphery of the connecting boss 502 is W. 22 The distance between the periphery of the positive current collector 5 and the inner wall of the casing 1 is W. 23 The distance between the 6th circumference of the injection pin and the inner wall of the injection hole 503 is W. 24 The angle between the periphery of the connecting boss 502 and the positive current collector 5 is B.

[0035] In some embodiments, H 20 =3.3mm-4.3mm, that is, the distance between the end of the core 3 near the positive electrode post 2 and the shell 1 is 3.3mm, 3.8mm or 4.3mm, etc.

[0036] In some embodiments, H 22 / H 20 =21%-31.6%, meaning the depth of the isolation groove 501 is 21%, 26.3%, or 31.6% of the distance between the end of the core 3 near the positive electrode post 2 and the shell 1, etc. If H 22 / H 20 If the depth of the isolation groove 501 is less than 21%, the connecting boss 502 is too close to the core 3. During welding of the positive electrode post 2 and the connecting boss 502, the high temperature of the welding will be transferred to the core 3, burning the separator in the core 3 and causing a short circuit in the battery. If H22 / H 20 If the depth of the isolation groove 501 is greater than 31.6%, the stamping difficulty of the isolation groove 501 will increase, making it difficult to guarantee the stability and consistency of the connecting boss 502. At the same time, the excessive depth of the isolation groove 501 will also reduce the structural strength of the connecting boss 502, affecting the overall structural strength of the battery and the production yield of the battery.

[0037] In some embodiments, H 23 / H 20 =21%-31.6%, meaning the distance between the positive current collector 5 and the positive terminal 2 is 21%, 26.3%, or 31.6% of the distance between the end of the core 3 closest to the positive terminal 2 and the casing 1, etc. If H 23 / H 20 If the distance between the positive current collector 5 and the positive terminal 2 is less than 21%, the distance between the connecting boss 502 and the core 3 is too small. During welding of the positive terminal 2 and the connecting boss 502, the high temperature of the welding will be transferred to the core 3, burning the separator in the core 3 and causing a short circuit in the battery. If H 23 / H 20 If the distance between the positive electrode current collector 5 and the positive electrode post 2 is too large, the stamping difficulty of the connecting boss 502 will increase, making it difficult to guarantee the stability and consistency of the connecting boss 502. At the same time, if the height of the connecting boss 502 is too large, it will also reduce the structural strength of the connecting boss 502, affecting the overall structural strength of the battery and the production yield of the battery.

[0038] In some embodiments, H 21 / H 20 =7.9%-13.2%, meaning the thickness of the positive current collector 5 is 7.9%, 10.5%, or 13.2% of the distance between the end of the core 3 closest to the positive electrode post 2 and the casing 1, etc. If H 21 / H 20 If the current density is less than 7.9%, the thickness of the positive current collector 5 is too small, the cross-sectional area of ​​the positive current collector 5 is reduced, the current carrying capacity of the positive current collector 5 decreases, resulting in an increase in the temperature rise of the positive current collector 5 during current carrying, which affects the safety performance of the battery; if H 21 / H 20 If the thickness is greater than 13.2%, then the thickness of the positive electrode current collector 5 is too large, which will not only increase the manufacturing cost of the battery, but also increase the weight of the battery, resulting in a decrease in the energy density of the battery.

[0039] In some embodiments, H 24 / H 20 =15.8%-26.3%, meaning the overall height of the positive electrode tab 4 is 15.8%, 21%, or 26.3% of the distance between the end of the core 3 closest to the positive electrode post 2 and the shell 1, etc. If H 24 / H20 If the height is less than 15.8%, the overall height of the positive electrode tab 4 is too small. During the welding of the positive current collector 5 and the positive electrode tab 4, the high welding temperature will be transferred to the core 3, damaging the separator inside the core 3 and increasing the risk of a battery short circuit. If H... 24 / H 20 If the height of the positive electrode tab 4 is greater than 26.3%, then the overall height of the positive electrode tab 4 is too large, and the positive electrode tab 4 occupies too much space, resulting in a decrease in battery capacity and energy density.

[0040] In some embodiments, W 21 =13.91mm-15.91mm, meaning the distance between the isolation groove 501 and the periphery of the positive current collector 5 is 13.91mm, 14.91mm, or 15.91mm, etc. If W 21 If the distance is less than 13.91mm, the gap between the isolation groove 501 and the periphery of the positive current collector 5 is too small, reducing the contact area between the positive current collector 5 and the positive electrode tab 4. This results in a reduction in the weldable area between the positive current collector 5 and the positive electrode tab 4, which in turn reduces the current carrying capacity at the welding point and increases the temperature rise at the welding line, affecting the battery's safety performance. 21 If the distance is greater than 15.91mm, the gap between the isolation groove 501 and the periphery of the positive current collector 5 will be too large, which will not only increase the processing cost of the positive current collector 5, but also increase the weight of the battery, resulting in a decrease in the energy density of the battery.

[0041] In some embodiments, W 22 =3.35mm-4.35mm, meaning the distance between the injection hole 503 and the periphery of the connecting boss 502 is 3.35mm, 3.85mm, or 4.35mm, etc. If W 22 If the distance is less than 3.35mm, the gap between the injection hole 503 and the periphery of the connecting boss 502 is too small, reducing the contact area between the connecting boss 502 and the positive terminal 2. This reduces the weldable area between the connecting boss 502 and the positive terminal 2, consequently decreasing the overcurrent capacity between the connecting boss 502 and the positive terminal 2, and increasing the temperature rise at the welding point, which will affect the battery's safety performance. If W 22 If the distance is greater than 4.35mm, the gap between the injection hole 503 and the periphery of the connecting boss 502 is too large, and the connecting boss 502 expands outward, resulting in a reduction in the contact area between the positive current collector 5 and the positive electrode tab 4. This reduces the weldable area between the positive current collector 5 and the positive electrode tab 4, which in turn reduces the current carrying capacity at the welding position of the positive current collector 5 and the positive electrode tab 4, and increases the temperature rise at the welding line, which will affect the safety performance of the battery.

[0042] In some embodiments, W 23 =1.05mm-1.65mm, meaning the distance between the periphery of the positive current collector 5 and the inner wall of the casing 1 is 1.05mm, 1.35mm, or 1.65mm, etc. If W23 If the diameter is less than 1.05mm, the distance between the periphery of the positive current collector 5 and the inner wall of the casing 1 is too small, and the outer diameter of the positive current collector 5 is too large. This will not only increase the production cost of the positive current collector 5, but also increase the weight of the battery, leading to a decrease in the energy density of the battery; if W 23 If the diameter is greater than 1.65mm, the distance between the periphery of the positive current collector 5 and the inner wall of the shell 1 is too large, and the outer diameter of the positive current collector 5 is too small. This results in a reduction in the contact area between the positive current collector 5 and the positive electrode tab 4 or a reduction in the contact area between the connecting boss 502 and the positive electrode post 2. Consequently, the weldable area is reduced, which in turn leads to a decrease in the current carrying capacity at the welding position and an increase in the temperature rise at the welding line, affecting the safety performance of the battery.

[0043] In some embodiments, W 24 =0.36mm-0.76mm, meaning the distance between the 6th circumference of the injection pin and the inner wall of the injection hole 503 is 0.36mm, 0.56mm, or 0.76mm, etc. If W 24 If the distance is less than 0.36mm, the gap between the periphery of the injection pin 6 and the inner wall of the injection hole 503 is too small, making it difficult for the injection pin 6 to be inserted into the injection hole 503, increasing the difficulty of battery assembly and reducing battery assembly efficiency; if W 24 If the distance is greater than 0.76mm, the gap between the periphery of the injection pin 6 and the inner wall of the injection hole 503 is too large, that is, the inner diameter of the injection hole 503 is too large. This will reduce the area of ​​the connecting boss 502, resulting in a smaller contact area between the connecting boss 502 and the positive electrode post 2. This reduces the weldable area between the connecting boss 502 and the positive electrode post 2, which in turn leads to a decrease in the current carrying capacity at the welding position between the connecting boss 502 and the positive electrode post 2, and an increase in the temperature rise at the welding line, affecting the safety performance of the battery.

[0044] In some embodiments, B = 118°-138°, that is, the angle between the periphery of the connecting boss 502 and the positive current collector 5 is 118°, 128° or 138°, etc. If B < 118°, the angle between the periphery of the connecting boss 502 and the positive current collector 5 is too small, which increases the processing difficulty of the connecting boss 502, reduces the yield of the battery, and increases the manufacturing cost. If B > 138°, the angle between the periphery of the connecting boss 502 and the positive current collector 5 is too large, and the structural strength of the connecting boss 502 is correspondingly weakened. During welding or use, the connecting boss 502 may collapse and deform, which may cause problems such as poor welding and missing welding at the welding position between the connecting boss 502 and the positive terminal 2, affecting the welding reliability between the connecting boss 502 and the positive terminal 2.

[0045] 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 lithium-ion cylindrical battery, comprising a casing (1), a positive electrode post (2), a winding core (3), a positive electrode tab (4), and a positive electrode current collector (5), wherein the positive electrode post (2) is disposed at the end of the casing (1), and the two are sealed and insulated; the winding core (3) is disposed inside the casing (1); the positive electrode tab (4) is connected to the winding core (3), and one end of the positive electrode tab (4) extends out of the end of the winding core (3); the positive electrode current collector (5) is fixedly disposed on the positive electrode tab (4); Its features are: An isolation groove (501) is provided in the middle of the positive electrode current collector (5) near the positive electrode tab (4), so that a connecting boss (502) is formed on the side of the positive electrode current collector (5) away from the positive electrode tab (4), and the connecting boss (502) is fixedly connected to the positive electrode post (2). The distance between the end of the core (3) near the positive electrode post (2) and the shell (1) is H. 20 The depth of the isolation groove (501) is H. 22 H 22 / H 20 =21%-31.6%.

2. A lithium-ion cylindrical battery as described in claim 1, characterized in that: The distance between the positive current collector (5) and the positive electrode post (2) is H. 23 H 23 / H 20 =21%-31.6%.

3. A lithium-ion cylindrical battery as described in claim 1, characterized in that: The thickness of the positive current collector (5) is H. 21 H 21 / H 20 =7.9%-13.2%.

4. A lithium-ion cylindrical battery as described in claim 1, characterized in that: The overall height of the positive electrode tab (4) is H. 24 H 24 / H 20 =15.8%-26.3%.

5. A lithium-ion cylindrical battery as described in claim 1, characterized in that: The distance between the isolation groove (501) and the periphery of the positive current collector (5) is W. 21 W 21 =13.91mm-15.91mm.

6. A lithium-ion cylindrical battery as described in claim 1, characterized in that: An injection hole (503) is provided inside the connecting boss (502), and the distance between the injection hole (503) and the periphery of the connecting boss (502) is W. 22 W 22 =3.35mm-4.35mm.

7. A lithium-ion cylindrical battery as described in claim 1, characterized in that: The peripheral side of the connecting boss (502) is tapered; The angle between the periphery of the connecting boss (502) and the positive current collector (5) is B, where B = 118°-138°.

8. A lithium-ion cylindrical battery as described in claim 1, characterized in that: The distance between the periphery of the positive current collector (5) and the inner wall of the housing (1) is W. 23 W 23 =1.05mm-1.65mm.

9. A lithium-ion cylindrical battery as described in claim 6, characterized in that: It also includes a liquid injection nail (6), wherein the positive electrode post (2) is provided with an assembly hole (201), the liquid injection nail (6) is disposed in the assembly hole (201) and located in the liquid injection hole (503); The distance between the periphery of the injection nail (6) and the inner wall of the injection hole (503) is W. 24 W 24 =0.36mm-0.76mm.

10. A lithium-ion cylindrical battery as described in any one of claims 1-9, characterized in that: H 20 =3.3mm-4.3mm。

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