Cylindrical lithium ion battery

Abstract

The utility model relates to the technical field of lithium batteries, and provides a cylindrical lithium ion battery, which comprises a positive collector plate and a roll core, a plate body is arranged on the positive collector plate, and the plate body is welded and fixed with the full-tab end face of the roll core; a liquid injection hole is preset in the center of the roll core, the radius of the liquid injection hole is R10, the radius of the disc body is R0, and the radius of the liquid injection hole and the radius of the disc body meet the condition that R10 / R0 = 11-18%; according to the cylindrical lithium ion battery, by reasonably setting the size of the liquid injection hole, the electrolyte injection efficiency, the battery structure stability, the safety performance and the energy density can be considered, so that the overall performance of the battery is effectively improved.

Description

Technical Field

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

[0002] A cylindrical battery is a type of battery composed of components such as a positive electrode, a negative electrode, a separator, an electrolyte, and a casing. It is cylindrical in shape. Its structure typically includes components such as a casing, a cap, a positive electrode, a negative electrode, a separator, an electrolyte, a PTC element, gaskets, and a safety valve. The edges of the cylindrical battery tabs are equipped with insulating tape to prevent the tabs from contacting the casing wall, which could cause poor casing voltage. This ensures that the battery can charge and discharge normally and provides protection in abnormal conditions.

[0003] A single-pass cylindrical battery with publication number CN220086334U includes a core, a positive current collector, a casing, and an explosion-proof valve. The positive tab of the core is connected to the positive current collector to form a core assembly. The core assembly is disposed within the casing, and the bottom of the casing along its height direction is connected to the positive current collector. The casing has a mounting groove and a first liquid injection hole, and the positive current collector has a second liquid injection hole. The mounting groove, the first liquid injection hole, and the second liquid injection hole are sequentially connected and correspond to the center hole of the core. The explosion-proof valve is disposed in the mounting groove.

[0004] The current setting of the electrolyte injection hole size needs to be within a reasonable range. Too large or too small will have bad effects. If the center hole of the core is too small, the electrolyte will flow in slowly, the injection and manufacturing efficiency will be reduced, and the cost will increase. If it is too large, it will lead to difficulties in casing, easy damage to the insulation protection layer, increased short circuit risk and safety performance problems, and a decrease in battery energy density. Utility Model Content

[0005] In view of this, this utility model proposes a cylindrical lithium-ion battery that, by reasonably setting the size of the electrolyte injection hole, can balance the electrolyte injection efficiency with the battery structure stability, safety performance and energy density, thereby effectively improving the overall performance of the battery.

[0006] The technical solution of this utility model is achieved as follows: This utility model provides a cylindrical lithium-ion battery, including a positive electrode current collector and a wound core, wherein,

[0007] The positive current collector is provided with a disk body, and the disk body is welded and fixed to the end face of the full-pole tab of the winding core;

[0008] The core has a liquid injection hole at its center with a radius of R10 and a disk radius of R0. The radius of the liquid injection hole and the disk radius satisfy: R10 / R0 = 11-18%.

[0009] Based on the above technical solutions, preferably, a through hole is provided in the center of the disc body, the radius of the through hole is R1, and the radius of the liquid injection hole and the radius of the through hole satisfy: R10 / R1=48-72%.

[0010] Based on the above technical solutions, preferably, the radius of the through hole and the radius of the disk body satisfy: R1 / R0=21-28%.

[0011] Based on the above technical solution, preferably, the disk body is provided with multiple exhaust holes, and the multiple exhaust holes are evenly distributed along the axis of the disk body and located outside the through hole. The radius of the exhaust hole is R2, and the radius of the exhaust hole and the radius of the disk body satisfy: R2 / R0=11-18%.

[0012] Based on the above technical solutions, preferably, the disk body is provided with an annular insulating member, and the insulating member is located at the edge of the disk body and outside the exhaust hole. The width of the insulating member is L3, and the width of the insulating member and the radius of the disk body satisfy: L3 / R0=25-34%.

[0013] Based on the above technical solutions, preferably, the shortest distance between the through hole and the exhaust hole is L1, and satisfies: L1 = 0.82-1.42mm.

[0014] Based on the above technical solutions, preferably, the shortest distance between the exhaust hole and the insulating component is L2, and L2 = 0.32-0.92 mm.

[0015] Based on the above technical solutions, preferably, the positive electrode current collector also includes a tail body and a bent portion, wherein the bent portion is bent toward the side away from the plate body, and the plate body is fixedly connected to the tail body through the bent portion, and the plate body, the tail body and the bent portion 13 are an integral structure, and the shortest distance between the through hole and the surface of the bent portion away from the liquid injection hole is L4, and satisfies: L4=2.64-3.44mm.

[0016] Based on the above technical solutions, preferably, the shortest distance between the side surface of the bent portion away from the injection hole and the insulating component is L5, and satisfies: L5 = 1.4-2.0 mm.

[0017] Based on the above technical solutions, preferably, the radius R0 of the disk body is 9.74-10.74mm.

[0018] The current collector soldering structure and cylindrical secondary battery of this invention have the following advantages over the prior art:

[0019] (1) By appropriately controlling the range ratio between the injection hole radius and the disk radius, the electrolyte injection efficiency, battery structure stability, safety performance and energy density can be balanced, thereby effectively improving the overall performance of the battery.

[0020] (2) By properly controlling the ratio of the through hole radius and the vent hole radius to the disk radius, the liquid injection efficiency and welding quality of the battery can be guaranteed, thereby ensuring the overall performance of the battery.

[0021] (3) By properly controlling the shortest distance between the side surface of the bending part away from the injection hole and the insulating part and the through hole respectively, the electronic transmission performance, safety performance and process assembly quality of the battery are guaranteed. Attached Figure Description

[0022] 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.

[0023] Figure 1 This is a schematic diagram of the structure of this utility model;

[0024] Figure 2 This is a schematic diagram showing the markings of the through hole and vent hole of this utility model;

[0025] Figure 3 This is a schematic diagram of the width marking of the insulating component of this utility model;

[0026] Figure 4 This is a schematic diagram showing the distance markings between the bent portion, the insulating component, and the injection hole of this utility model. Detailed Implementation

[0027] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. 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 of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0028] like Figure 1As shown, a cylindrical lithium-ion battery of this utility model includes a positive electrode current collector 1 and a winding core 2. The positive electrode current collector 1 is provided with a disk body 11, which is welded and fixed to the end face of the tab of the winding core 2. The center of the winding core 2 is preset with a liquid injection hole 200, the radius of the liquid injection hole 200 is R10, the radius of the disk body 11 is R0, and the radius of the liquid injection hole 200 and the radius of the disk body 11 satisfy: R10 / R0=11-18%, and the radius of the disk body 11 R0=9.74-10.74mm.

[0029] It should be noted that during the lithium-ion battery manufacturing process, the electrolyte is injected into the core 2 through the injection hole 200. The injection speed of the electrolyte is closely related to the area of ​​the injection hole 200. The larger the area of ​​the injection hole 200, the larger the volume of electrolyte passing through the injection hole 200 per unit time under the same injection pressure, and the faster the injection speed. When the R10 / R0 ratio is too small, the radius R10 of the injection hole 200 is smaller than the radius R0 of the disk 11, and the area of ​​the injection hole 200 will also decrease accordingly. According to the principles of fluid mechanics, under a constant injection pressure, a smaller injection hole 200 area will result in electrolyte flowing through the core 200 more quickly. The reduced flow rate of the injection hole 200 slows down the rate at which the electrolyte flows into the core 2. When the ratio of the radius of the injection hole 200 to the radius of the disc 11 is too large, the radius R10 of the injection hole 200 will increase in order to ensure that the area of ​​the injection hole 200 is large enough, while the radius R0 of the disc 11 is fixed. This results in an increase in the overall diameter of the core 2. The increase in the radius of the injection hole 200 may increase the size of the core 2 in the radial direction, and the diameter of the core 2 will increase accordingly. This will make it difficult to insert the core into the casing and may easily damage the insulating protective layer such as the separator at the outer end of the core 2, increasing the risk of short circuit in the battery, reducing safety performance, and causing a decrease in the energy density of the battery.

[0030] like Figure 2 As shown, this embodiment, by appropriately controlling the ratio of the radius of the injection hole 200 to the radius of the disk 11, R10 / R0 = 11-18%, can balance the electrolyte injection efficiency with the battery structure stability, safety performance and energy density, thereby effectively improving the overall battery performance.

[0031] Specifically, in this embodiment, the radius of the disc body 11 is R0 = 10.24 mm, and the ratio of the radius of the injection hole 200 to the radius of the disc body 11 is R10 / R0 = 15%.

[0032] like Figure 2 As shown, the center of the disc body 11 in this embodiment has a through hole 100 with a radius of R1. The radius of the liquid injection hole 200 and the radius of the through hole 100 satisfy: R10 / R1 = 48-72%; the radius of the through hole 100 and the radius of the disc body 11 satisfy: R1 / R0 = 21-28%.

[0033] It should be noted that when the R1 / R0 ratio is too small, the radius R1 of the through hole 100 is relatively small compared to the radius R0 of the disk body, and the area of ​​the through hole 100 will also decrease accordingly. It is more difficult for the electrolyte to enter the battery, and there are not enough channels for it to flow into the battery. The limitation of the channel area reduces the volume of electrolyte passing through per unit time, resulting in a decrease in electrolyte injection efficiency. When the R1 / R0 ratio is too large, the radius R1 of the through hole 100 increases, and the area of ​​the through hole 100 increases, which will occupy more area on the disk body 11. This will affect the weldable area of ​​the disk body 11 of the positive electrode current collector 1, resulting in insufficient welding area when welding the disk body 11 and the positive electrode side of the core. The effective welding area is reduced, the temperature at the welding line increases, and the battery performance is affected.

[0034] In this embodiment, the ratio of the radius of the through hole 100 to the radius of the disk 11 is appropriately controlled to satisfy R1 / R0 = 21-28%, so as to ensure the electrolyte injection efficiency and welding quality of the battery, thereby ensuring the overall performance of the battery.

[0035] Specifically, in this embodiment, the radius of the through hole 100 is 24% of the radius of the disk body 11, R1 / R0.

[0036] like Figure 2 As shown, in this embodiment, the disk body 11 is provided with a plurality of exhaust holes 110, and the plurality of exhaust holes 110 are evenly distributed along the axis of the disk body 11 and located outside the through hole 100. The radius of the exhaust hole 110 is R2, and the radius of the exhaust hole 110 and the radius of the disk body 11 satisfy: R2 / R0=11-18%.

[0037] It should be noted that during the battery electrolyte filling stage, the space formed by the vent hole 100, to a certain extent, facilitates the flow and distribution of the liquid in the vicinity of the disk 11. The presence of the vent hole 100 can create a certain channel effect in a local area, helping the electrolyte to enter the battery more smoothly. When the R2 / R0 ratio is too small, the radius R2 of the vent hole 100 is smaller than the radius R0 of the disk 11, and the area of ​​the vent hole 100 is correspondingly reduced. This narrows the auxiliary flow channel provided by the vent hole 100 for the electrolyte, making it difficult for the electrolyte to smoothly enter the battery through the area where the vent hole is located. In some cases, there are insufficient channels for the electrolyte to flow into the battery. The limited area of ​​the channel 100 reduces the volume of electrolyte passing through per unit time, resulting in a decrease in electrolyte injection efficiency. When the R2 / R0 ratio is too large, the radius R2 of the vent hole 100 increases, and the area of ​​the vent hole 100 increases. Multiple vent holes 100 will occupy a large area on the disk surface 11. This affects the weldable area of ​​the positive electrode current collector 11, resulting in insufficient welding area when welding the disk body 11 and the positive electrode side of the core. The effective welding area is reduced, the temperature at the welding line increases, and the battery performance is affected.

[0038] In this embodiment, the ratio of the radius of the vent hole 110 to the radius of the disk body 11 is appropriately controlled to meet the range of 11-18%, so as to ensure the electrolyte injection efficiency and welding quality of the battery, thereby ensuring the overall performance of the battery.

[0039] Specifically, in this embodiment, the ratio of the radius of the vent hole 110 to the radius of the disc body 11 is R2 / R0 = 15%.

[0040] like Figure 3 As shown, in this embodiment, an insulating member 3 in the shape of a ring is provided on the upper part of the disc body 11, and the insulating member 3 is located at the edge of the disc body 11 and outside the exhaust hole 110. The width of the insulating member 3 is L3, and the width of the insulating member 3 and the radius of the disc body 11 satisfy: L3 / R0=25-34%.

[0041] It should be noted that the insulating component 3 is used to insulate and isolate the positive electrode current collector 1 of the battery from the battery casing and other components, while also serving a fixing and protection function. The insulating component 3 needs to have a certain width to ensure that it can firmly wrap around the edge of the disk 11 and prevent it from flipping up. The insulating component 3 is wrapped with tape around the edge of the disk 1. When L3 / R0 is too small, the width of the insulating component 3 is too narrow. When the width of the insulating component 3 is insufficient, the insulating component 3 is easy to fail to wrap properly and when it flips up, the tape cannot play its insulation and fixing role, further increasing the risk of short circuit between the positive electrode side and the battery casing, resulting in a decrease in battery safety. When L3 / R0 is too large, it will increase the amount of tape used, increase the manufacturing cost of the battery, and increase the weight of the battery, which will lead to a decrease in its energy density. After the edge of the insulating component 3 is widened, it is easy to cover the through hole 100 and the vent hole 110, hindering the injection of electrolyte and the discharge of gas, thereby affecting the normal process and performance of the battery.

[0042] This embodiment achieves a balance between electrolyte injection efficiency, manufacturing cost, safety performance, and energy density by appropriately controlling the ratio of the width of the insulating component 3 to the radius of the disk body 11 to 25-34%, thereby effectively improving battery safety performance.

[0043] Specifically, in this embodiment, the ratio of the width of the insulating member 3 to the radius of the disk body 11 is L3 / R0 = 29%.

[0044] like Figure 3 As shown, in this embodiment, the shortest distance between the through hole 100 and the vent hole 110 is L1, and satisfies: L1 = 0.82-1.42 mm.

[0045] It should be noted that when L1 is too small, the material in this area is relatively scarce and the structure is weak. When subjected to external forces during battery manufacturing, transportation, and use, this area is prone to deformation or even breakage. After breakage, metal shavings are easily generated, causing a short circuit in the battery and reducing its safety performance. When L2 is too small, in order to ensure the rationality of the overall structure of the disc 11 and the uniformity of the hole distribution, the outer vent will be moved outward accordingly, and its position will be closer to the edge of the disc 11. During the encapsulation process, the insulating part 3 is prone to covering the outer vent 110. After the vent 110 is covered by tape, it will hinder the flow of electrolyte during the injection process, reduce the electrolyte flow rate, and thus reduce the injection efficiency, affecting the battery manufacturing process and performance consistency.

[0046] In this embodiment, the shortest distance between the through hole 100 and the vent hole 110 is appropriately controlled to meet the range of 0.82-1.42mm, so as to ensure the structural strength, welding quality, electrolyte injection efficiency and safety performance of the battery.

[0047] Specifically, in this embodiment, the shortest distance between the through hole 100 and the vent hole 110 is L1 = 1.13 mm.

[0048] like Figure 3 As shown, the shortest distance between the exhaust port 110 and the insulating member 3 in this embodiment is L2, and L2 = 0.32-0.92 mm.

[0049] It should be noted that when the shortest distance L2 between the vent and the insulating component is too small, during the encapsulation process, due to the extensibility and adhesion of the encapsulation material, the tape may exceed the expected range and cover the outer vent, resulting in a decrease in electrolyte inflow rate and reduced injection efficiency. When the shortest distance L2 between the vent and the insulating component is too large, the outer vent will move inward towards the center of the disk, shortening the distance between the vent and the center hole. This reduces the material distribution in this area and lowers the structural strength. This area is more susceptible to deformation or even breakage under external forces. When deformed, the surrounding weldable areas also deform, increasing the possibility of incomplete welds during welding. Furthermore, this area is prone to breakage, which can generate metal shavings, causing a short circuit in the battery and reducing its safety performance.

[0050] In this embodiment, the minimum distance between the vent 110 and the insulating component 3 is appropriately controlled to meet the range of 0.32-0.92mm, so as to ensure the structural strength, welding quality, electrolyte injection efficiency and safety performance of the battery.

[0051] Specifically, in this embodiment, the shortest distance L2 between the vent 110 and the insulating member 3 is 0.62 mm.

[0052] like Figure 4As shown, the positive current collector 1 in this embodiment also includes a tail body 12 and a bent portion 13. The bent portion 13 is bent toward the side away from the plate body 11, and the plate body 11 is fixedly connected to the tail body 12 through the bent portion 13. The plate body 11, the tail body 12 and the bent portion 13 are an integral structure. The shortest distance between the through hole 100 and the surface of the bent portion 13 away from the liquid injection hole 200 is L4, and satisfies: L4 = 2.64-3.44mm.

[0053] It should be noted that in the battery, the positive electrode current collector 1 plays the role of collecting and conducting electrons. Electrons start from the positive electrode material inside the battery, pass through the bonding wires on the disk body 11, and then reach the connection between the disk body 11 and the tail end 12 from both sides of the disk body 11, thus realizing electron transfer. When L4 is too small, the connection between the disk body 11 and the tail end 12 of the positive electrode current collector 1 moves towards the center of the disk body 11, and the effective current transfer distance becomes shorter. This will cause electrons to be too concentrated during the transfer process, resulting in insufficient effective current transfer area. Under a constant current, insufficient current transfer area will increase resistance, which in turn will increase the heat generated by the battery during electron transfer. When L4 is too large, an insulating ring will be placed on the insulating component 3 during the battery manufacturing process. If the distance between the disk body 11 and the tail end 12 of the current collector 1 is too large, the insulating ring will interfere with the connection between the disk body 11 and the tail end 12 when it is inserted from the tail end 12, causing poor assembly and increasing the rate of poor insertion of the insulating ring.

[0054] In this embodiment, the shortest distance between the through hole 100 and the side surface of the bent portion 13 away from the injection hole 200 is appropriately controlled to meet the range of 2.64-3.44mm, so as to ensure the electronic transmission performance, safety performance and process assembly quality of the battery.

[0055] Specifically, in this embodiment, the shortest distance L4 between the through hole 100 and the side surface of the bent portion 13 away from the injection hole 200 is 3.04 mm.

[0056] like Figure 4 As shown, in this embodiment, the shortest distance between the side surface of the bent portion 13 away from the injection hole 200 and the insulating member 3 is L5, and satisfies: L5 = 1.4-2.0 mm.

[0057] It should be noted that when L5 is too small, the insulating ring interferes with the connection between the disk body 11 and the tail end 12 of the positive current collector 1, which will cause the insulating ring to fail to fit properly into the designated position, resulting in poor assembly and affecting the production efficiency and quality stability of the battery. When L5 is too large, the connection between the disk body 11 and the tail end 12 of the positive current collector 1 moves towards the center of the disk body 11. However, the path of electron transmission is through the welding wire on the disk body 11 and then from both sides of the disk body 11 to the connection between the disk body 11 and the tail end 12. However, after the connection between the disk body 11 and the tail end 12 moves inward to the disk body 11, the effective current passage distance becomes shorter, resulting in insufficient effective current passage area during electron transmission, causing the battery to generate heat and reducing safety performance.

[0058] In this embodiment, the shortest distance between the side surface of the bent portion 13 away from the injection hole 200 and the insulating component 3 is appropriately controlled to meet the range of 1.4-2.0mm, so as to ensure the electronic transmission performance, safety performance and process assembly quality of the battery.

[0059] Specifically, in this embodiment, the shortest distance L5 between the side surface of the bent portion 13 away from the injection hole 200 and the insulating member 3 is 1.7mm.

[0060] 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-ion battery, characterized in that, It includes a positive current collector (1) and a winding core (2), wherein, The positive current collector (1) is provided with a disk body (11), and the disk body (11) is welded and fixed to the end face of the full-pole tab of the core (2); The core (2) has a liquid injection hole (200) at its center. The radius of the liquid injection hole (200) is R10, and the radius of the disc (11) is R0. The radius of the liquid injection hole (200) and the radius of the disc (11) satisfy: R10 / R0 = 11-18%.

2. The cylindrical lithium-ion battery as described in claim 1, characterized in that: The center of the disc (11) has a through hole (100) with a radius of R1, and the radius of the injection hole (200) and the radius of the through hole (100) satisfy: R10 / R1=48-72%.

3. The cylindrical lithium-ion battery as described in claim 2, characterized in that: The radius of the through hole (100) and the radius of the disk body (11) satisfy: R1 / R0 = 21-28%.

4. The cylindrical lithium-ion battery as described in claim 2, characterized in that: The disk body (11) has multiple exhaust holes (110) and is located outside the through hole (100). The radius of the exhaust hole (110) is R2, and the radius of the exhaust hole (110) and the radius of the disk body (11) satisfy: R2 / R0=11-18%.

5. The cylindrical lithium-ion battery as described in claim 4, characterized in that: An insulating member (3) in the shape of a ring is provided on the disk body (11), and the insulating member (3) is located at the edge of the disk body (11) and outside the exhaust hole (110). The width of the insulating member (3) is L3, and the width of the insulating member (3) and the radius of the disk body (11) satisfy: L3 / R0=25-34%.

6. The cylindrical lithium-ion battery as described in claim 5, characterized in that: The shortest distance between the through hole (100) and the vent hole (110) is L1, and satisfies: L1 = 0.82-1.42 mm.

7. The cylindrical lithium-ion battery as described in claim 5, characterized in that: The shortest distance between the exhaust port (110) and the insulating component (3) is L2, and L2 = 0.32-0.92 mm.

8. The cylindrical lithium-ion battery as described in claim 2, characterized in that: The positive current collector (1) also includes a tail body (12) and a bent portion (13), wherein the bent portion (13) is bent toward the side away from the plate body (11), and the plate body (11) is fixedly connected to the tail body (12) through the bent portion (13), and the plate body (11), the tail body (12) and the bent portion (13) are an integral structure. The shortest distance between the through hole (100) and the surface of the bent portion (13) away from the liquid injection hole (200) is L4, and satisfies: L4 = 2.64-3.44mm.

9. The cylindrical lithium-ion battery as described in claim 8, characterized in that: The shortest distance between the side surface of the bent portion (13) away from the injection hole (200) and the insulating component (3) is L5, and satisfies: L5 = 1.4-2.0 mm.

10. The cylindrical lithium-ion battery as described in claim 1, characterized in that: The radius R0 of the disk body (11) is 9.74-10.74 mm.

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