A cylindrical lithium-ion battery
By optimizing the design of the overmolding and injection holes, the short-circuit risk and manufacturing cost issues of cylindrical lithium-ion batteries have been resolved, resulting in improved safety and energy density.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU RELIANCE ENERGY TECHNOLOGY CO LTD
- Filing Date
- 2025-06-16
- Publication Date
- 2026-06-30
AI Technical Summary
The existing cylindrical lithium-ion battery has an unreasonable encapsulation design, which leads to an increased risk of short circuits or an increase in manufacturing costs and weight, as well as a decrease in energy density.
Optimize the area ratio of the overlay extending on the positive electrode current collector surface, the area ratio of the injection hole, and the distance ratio to ensure the insulation effect between the overlay and the battery casing, while reducing tape usage and improving injection efficiency.
It reduces the risk of battery short circuits, reduces manufacturing costs, improves energy density and production efficiency, and ensures battery safety performance.
Smart Images
Figure CN224437866U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of new energy battery technology, and in particular to a cylindrical lithium-ion battery. Background Technology
[0002] Based on packaging form, lithium batteries can be divided into three types: prismatic, cylindrical, and pouch. Among them, cylindrical lithium-ion batteries have gradually become a research hotspot due to their advantages such as good consistency, high production efficiency, and strong system-level heat dissipation. A cylindrical lithium-ion battery typically includes a battery casing, a core, a cap, a positive current collector, and a negative current collector. The core is mounted in the battery casing, and the negative current collector is located at the bottom of the core, connecting the negative electrode of the core to the battery casing, thus leading out the negative electrode through the battery casing. The cap is located at the top of the battery casing, and the positive current collector is located between the top of the core and the cap, connecting the positive electrode of the core to the cap, thus leading out the negative electrode through the cap.
[0003] Since the positive current collector is located between the top of the core and the cap, it is also located inside the battery casing. The battery casing is negatively charged, while the positive current collector is positively charged. To prevent the positive current collector from contacting the inner wall of the battery casing and causing a short circuit, an adhesive coating is usually provided on the outer periphery of the positive current collector. The adhesive coating extends from the outer periphery of the positive current collector to the upper surface, thereby isolating the positive current collector from the battery casing and preventing a short circuit.
[0004] Existing cylindrical lithium-ion batteries have flawed encapsulation designs, particularly regarding the width of the encapsulation extending onto the positive electrode current collector. Some cylindrical lithium-ion batteries have an excessively narrow encapsulation width, causing the flange at the junction of the outer and upper surfaces of the current collector to easily lift, failing to provide adequate insulation and increasing the risk of short circuits. Conversely, some cylindrical lithium-ion batteries have an excessively wide encapsulation width, increasing both the amount of adhesive used and manufacturing costs, as well as the battery's weight, leading to a decrease in energy density. Utility Model Content
[0005] The purpose of this invention is to address the shortcomings of the prior art by providing a cylindrical lithium-ion battery that can ensure the insulation effect of the coating on the positive electrode current collector and the battery casing, reduce the risk of short circuits and thus improve battery safety, while also reducing the use of tape, reducing battery weight, thereby lowering manufacturing costs and increasing battery energy density.
[0006] This utility model proposes a cylindrical lithium-ion battery, including a positive electrode current collector and an adhesive coating disposed on the outer periphery of the positive electrode current collector. The adhesive coating is used to insulate the positive electrode current collector from the battery casing. The positive electrode current collector includes a disk body. Part of the adhesive coating covers the outer peripheral surface of the disk body, and another part extends on the upper surface of the disk body. The radius of the disk body is R0, the cross-sectional area of the disk body calculated with the radius R0 is S0, the width of the adhesive coating extending on the upper surface of the disk body is L3, the area of the adhesive coating extending on the upper surface of the disk body calculated with the width L3 is S3, and the ratio of the area of the adhesive coating extending on the upper surface of the disk body S3 to the cross-sectional area S0 of the disk body, S3 / S0, is 44% to 56%.
[0007] Furthermore, the disc body is provided with a first liquid injection hole, the first liquid injection hole is coaxial with the disc body, the radius of the first liquid injection hole is R1, the cross-sectional area of the first liquid injection hole calculated with radius R1 is S1, and the ratio of the cross-sectional area S1 of the first liquid injection hole to the cross-sectional area S0 of the disc body, S1 / S0, is 4% to 8%.
[0008] Furthermore, the disc body is also provided with a second liquid injection hole, which is distributed outside the first liquid injection hole. The radius of the second liquid injection hole is R2, and the cross-sectional area of the second liquid injection hole calculated with radius R2 is S2. The ratio of the cross-sectional area S2 of the second liquid injection hole to the cross-sectional area S0 of the disc body, S2 / S0, is 1.2% to 3.2%.
[0009] Furthermore, the second injection hole is provided on the disc body in multiple ways, and the ratio of the sum of the cross-sectional areas S20 of the multiple second injection holes to the cross-sectional area S0 of the disc body, S20 / S0, is 4% to 10%.
[0010] Furthermore, the cylindrical lithium-ion battery also includes a core, the positive electrode tab of which is flattened to form a flattened layer, the flattened layer being connected to the disc body. The core is provided with a third liquid injection hole penetrating the flattened layer, the third liquid injection hole being coaxial with the first liquid injection hole, the radius of the third liquid injection hole being R10, the cross-sectional area of the third liquid injection hole calculated with radius R10 being S10, and the ratio of the cross-sectional area S10 of the third liquid injection hole to the cross-sectional area S0 of the disc body, S10 / S0, being 1% to 3%.
[0011] Furthermore, the ratio of the minimum distance L1 between the first injection hole and the second injection hole to the radius R0 of the disc body, L1 / R0, is 8% to 14%.
[0012] Furthermore, the minimum distance L2 between the second injection hole and the extended portion of the coating on the upper surface of the disc body, and the ratio L2 / R0 of the disc body, is 3% to 9%.
[0013] Furthermore, the positive electrode current collector also includes a tail body for connecting to the lower end plate of the cap, and a bent portion connected at one end to the plate body and at the other end to the tail body; the minimum distance L4 between the bent portion connected to the plate body and the first injection hole is 25% to 34% of the ratio of L4 / R0 to the radius R0 of the plate body.
[0014] Furthermore, the positive current collector also includes a tail body for connecting to the lower end plate of the cap, and a bent portion connected at one end to the disk body and at the other end to the tail body; the minimum distance L5 between the end of the bent portion connected to the disk body and the extension portion of the rubber coating on the upper surface of the disk body is 13% to 20% of the radius R0 of the disk body.
[0015] Furthermore, the radius R0 of the disk body ranges from 9.74 mm to 10.74 mm.
[0016] The cylindrical lithium-ion battery proposed in this utility model has the following beneficial effects:
[0017] (1) The ratio of the area S3 of the coating extending on the upper surface of the disk to the cross-sectional area S0 of the disk is set between 44% and 56% in this battery. This ensures that the coating can effectively isolate the positive current collector from the battery casing, thereby reducing the risk of short circuit and improving the safety of the battery. It also reduces the use of tape, reduces the weight of the battery, thereby reducing the manufacturing cost of the battery and increasing the energy density of the battery.
[0018] (2) The ratio of the cross-sectional area S1 of the first liquid injection hole to the cross-sectional area S0 of the disk body is set between 4% and 8% in this battery. This prevents the radius of the first liquid injection hole from being too small, which would affect the liquid injection efficiency of the battery and thus improve the production efficiency of the battery. It also prevents the radius of the first liquid injection hole from being too large, which would affect the effective welding area on the disk body that can be used to weld the positive electrode of the core, thus ensuring the safety performance of the battery.
[0019] (3) The ratio of the cross-sectional area S2 of the second liquid injection hole to the cross-sectional area S0 of the disk body is set between 1.2% and 3.2% in this battery. This prevents the radius of the second liquid injection hole from being too small or too large, thereby further improving the production efficiency of the battery and ensuring the safety performance of the battery.
[0020] (4) The ratio of the sum of the cross-sectional areas of the multiple second liquid injection holes S20 to the cross-sectional area S0 of the disc body S20 / S0 is set between 4% and 10% in this battery. This prevents the sum of the cross-sectional areas of the multiple second liquid injection holes from being too small, which would affect the liquid injection efficiency of the battery and thus improve the production efficiency of the battery. It also prevents the sum of the cross-sectional areas of the multiple second liquid injection holes from being too large, which would reduce the effective welding area of the disc surface on the disc body that can be used to weld to the positive electrode of the core, thus ensuring the safety performance of the battery.
[0021] (5) The ratio of the cross-sectional area S10 of the third liquid injection hole to the cross-sectional area S0 of the disc body, S10 / S0, is set between 1% and 3% in this battery. This prevents the radius of the third liquid injection hole from being too small, which would affect the liquid injection efficiency of the battery and thus improve the production efficiency of the battery. It also prevents the radius of the third liquid injection hole from being too large, which would affect the effective welding area of the flattened layer that can be used for welding with the disc surface, thus ensuring the safety performance of the battery.
[0022] (6) The ratio of the minimum distance L1 between the first and second injection holes to the radius R0 of the disk body is set between 8% and 14% in this battery. This prevents the minimum distance L1 between the first and second injection holes from being too small, which would affect the structural strength of the disk body and thus ensure the safety performance of the battery. It also prevents the minimum distance L1 between the first and second injection holes from being too large, which would affect the speed at which the electrolyte enters the core through the second injection hole and thus improve the injection efficiency of the battery.
[0023] (7) The ratio of the minimum distance L2 between the second injection hole and the extension of the rubber coating on the upper surface of the disc to the radius R0 of the disc is set between 3% and 9%. This prevents the minimum distance L2 between the second injection hole and the extension of the rubber coating on the upper surface of the disc from being too small, which would affect the speed at which the electrolyte enters the core through the second injection hole, thereby improving the injection efficiency of the battery. It also prevents the minimum distance L2 between the second injection hole and the extension of the rubber coating on the upper surface of the disc from being too large, which would affect the structural strength of the disc, thereby ensuring the safety performance of the battery.
[0024] (8) The ratio of the minimum distance L4 between the end of the bent part connecting the plate and the first liquid injection hole to the radius R0 of the plate is set between 25% and 34% in this battery. This prevents the bent part from moving too inward, reducing the overcurrent area of the positive electrode current collector, thus ensuring the safety performance of the battery. It also prevents the bent part from moving too outward, affecting the insertion of the insulating ring, thus reducing the manufacturing difficulty of the battery and improving production efficiency.
[0025] (9) The ratio of the minimum distance L5 between the end of the bent part connecting the disc and the extension of the rubber coating on the upper surface of the disc to the radius R0 of the disc is set between 13% and 20%. This prevents the bent part from moving too inward, reducing the overcurrent area of the positive electrode current collector, thus ensuring the safety performance of the battery. It also prevents the bent part from moving too outward, affecting the insertion of the insulating ring, thereby reducing the manufacturing difficulty of the battery and improving production efficiency. Attached Figure Description
[0026] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the present invention and, together with the description, serve to explain the principles of the present invention. In these drawings, similar reference numerals are used to denote similar elements.
[0027] Figure 1 This is a schematic diagram of the planar structure of a cylindrical lithium-ion battery according to an embodiment of the present utility model;
[0028] Figure 2 for Figure 1 Enlarged view of point A in the middle;
[0029] Figure 3 for Figure 1 Enlarged view of point B in the middle;
[0030] Figure 4 for Figure 1 Enlarged diagram of point C in the middle.
[0031] In the diagram: 1. Disc body; 11. First injection hole; 12. Second injection hole; 2. Tail body; 3. Bending part; 4. Glue coating; 5. Flattening layer; 51. Third injection hole. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. All other embodiments obtained by those skilled in the art based on the embodiments of this utility model without creative effort are within the scope of protection of this utility model.
[0033] Please see Figures 1-4 A cylindrical lithium-ion battery according to an embodiment of the present invention includes a positive electrode current collector and an adhesive 4 disposed on the outer periphery of the positive electrode current collector. The adhesive 4 is used to insulate the positive electrode current collector from the battery casing. The positive electrode current collector includes a disk body 1. Part of the adhesive 4 covers the outer peripheral surface of the disk body 1, and another part extends on the upper surface of the disk body 1.
[0034] In this application, the cylindrical lithium-ion battery includes a positive current collector, which is disposed between the top of the core and the cap. The positive current collector connects the positive electrode of the core to the cap, so that the cap leads out the positive electrode of the core, i.e., the cap is the positive electrode of the cylindrical lithium-ion battery; the battery casing leads out the negative electrode of the core, i.e., the battery casing is the negative electrode of the cylindrical lithium-ion battery.
[0035] Since the positive current collector is located between the top of the core and the cap, it is also located inside the battery casing. The battery casing carries a negative charge, while the positive current collector carries a positive charge. To prevent the positive current collector from contacting the inner wall of the battery casing and causing a short circuit, in this application, the cylindrical lithium-ion battery also includes an adhesive coating 4. The adhesive coating 4 is disposed on the outer periphery of the positive current collector, isolating it from the battery casing and thus preventing a short circuit.
[0036] Specifically, the positive current collector includes a disk body 1, which is welded to the positive electrode of the winding core, thereby connecting the positive current collector to the positive electrode of the winding core. A portion of the adhesive 4 covers the outer circumference of the disk body 1, and another portion extends to the upper surface of the disk body 1. This adhesive 4 covers the area of the disk body 1 near the inner wall of the battery casing, isolating it from the battery casing and preventing contact between the disk body 1 and the battery casing, which could lead to a short circuit.
[0037] In practical use, if the width of the adhesive tape 4 extending on the upper surface of the disc 1 is too small, the flange of the adhesive tape 4 at the junction of the outer periphery and the upper surface of the disc 1 will easily lift up, failing to achieve the proper insulation effect, thus increasing the risk of battery short circuit; on the other hand, if the width of the adhesive tape 4 extending on the upper surface of the disc 1 is too large, it will increase the amount of tape used, thereby increasing the battery manufacturing cost, and will also increase the weight of the battery, thus causing a decrease in the energy density of the battery.
[0038] The radius of the disc body 1 is set to R0, the cross-sectional area of the disc body 1 calculated with radius R0 is S0, the width of the coating 4 extending on the upper surface of the disc body 1 is set to L3, and the area of the coating 4 extending on the upper surface of the disc body 1 calculated with width L3 is S3.
[0039] Therefore, in this application, the ratio S3 / S0 of the area S3 extending from the upper surface of the coating 4 on the disk body 1 to the cross-sectional area S0 of the disk body 1 is set between 44% and 56%. This prevents the width L0 of the coating 4 extending from the upper surface of the disk body 1 from being too small, thus ensuring the isolation effect of the coating 4 between the positive electrode current collector and the battery casing, reducing the risk of short circuit in the battery, and thus improving battery safety. It also prevents the width L0 of the coating 4 extending from the upper surface of the disk body 1 from being too large, thereby reducing the use of tape, reducing battery weight, and thus reducing battery manufacturing costs and increasing battery energy density. Preferably, in this application, the ratio S3 / S0 is set to 50%.
[0040] Since electrolyte needs to be injected into the battery casing during the manufacturing process of cylindrical lithium-ion batteries, so that the electrolyte fills the gaps between the electrodes and the micropores of the separator in the core, ensuring that the electrochemical reaction of the battery proceeds efficiently, in this embodiment, a first injection hole 11 is provided on the disk body 1, and the first injection hole 11 is coaxial with the disk body 1.
[0041] Since the cap seals the top opening of the battery casing, it is foreseeable that an injection port is pre-installed at the center of the cap, and this injection port is coaxial with the first injection hole 11 on the disc 1, thereby injecting external electrolyte into the battery casing through the injection port. Furthermore, since the disc 1 is located at the top of the winding core, the electrolyte entering the battery casing flows through the first injection hole 11 and then into the winding core, filling the gaps between the electrodes and the micropores of the separator, thus completing the electrolyte injection into the battery.
[0042] In practical use, if the radius of the first injection hole 11 is too small, the flow rate of electrolyte through the first injection hole 11 will be too slow, thereby reducing the injection efficiency and thus reducing the production efficiency of the battery. If the radius of the first injection hole 11 is too large, the effective welding area will be reduced when the disc surface of the disc body 1 and the positive electrode of the core are welded, thereby causing the temperature at the welding line to rise and affecting the safety performance of the battery.
[0043] The radius of the first injection hole 11 is set to R1, and the cross-sectional area of the first injection hole 11 calculated with radius R1 is S1. In this application, the ratio S1 / S0 of the cross-sectional area S1 of the first injection hole 11 to the cross-sectional area S0 of the disk body 1 is set between 4% and 8%. This prevents the radius of the first injection hole 11 from being too small, which would affect the injection efficiency of the battery and thus improve the battery production efficiency. It also prevents the radius of the first injection hole 11 from being too large, which would affect the effective welding area on the disk surface of the disk body 1 that can be used for welding to the positive electrode of the winding core, thereby ensuring the safety performance of the battery. Preferably, in this application, the ratio S1 / S0 is set to 6%.
[0044] Since the disc body 1 is located at the top of the winding core, the electrolyte injected into the battery casing through the injection port on the cap must pass through the disc body 1 before entering the winding core. In this embodiment, a second injection hole 12 is also provided on the disc body 1, and the second injection hole 12 is distributed outside the first injection hole 11.
[0045] When electrolyte is injected into the battery casing through the injection port on the cap, if the flow rate of the electrolyte injected from the injection port is greater than the flow rate of the electrolyte flowing through the first injection hole 11, the excess electrolyte will diffuse to the outside of the first injection hole 11. At this time, the electrolyte that has diffused to the outside of the first injection hole 11 can enter the core through the second injection hole 12, thereby assisting the first injection hole 11 in injecting electrolyte through the second injection hole 12, improving the electrolyte injection efficiency of the battery, and thus improving the battery production efficiency.
[0046] In practical use, if the radius of the second liquid injection hole 12 is too small, it will affect the liquid injection efficiency, thereby reducing the battery production efficiency; if the radius of the second liquid injection hole 12 is too large, it will reduce the effective welding area on the disc surface of the disc body 1 that can be used to weld with the positive electrode of the core, thereby affecting the safety performance of the battery.
[0047] The radius of the second injection hole 12 is set to R2, and the cross-sectional area of the second injection hole 12 calculated using radius R2 is S2. In this application, the ratio S2 / S0 of the cross-sectional area S2 of the second injection hole 12 to the cross-sectional area S0 of the disk body 1 is set between 1.2% and 3.2%, which prevents the radius of the second injection hole 12 from being too small or too large, thereby further improving the battery production efficiency and ensuring the battery safety performance. Preferably, in this application, the ratio S2 / S0 is set to 2%.
[0048] Furthermore, in this embodiment, there are multiple second injection holes 12 disposed on the disk body 1, and the multiple second injection holes 12 are distributed at equal intervals along the circumference outside the first injection hole 11. When the flow rate of electrolyte injected from the injection port on the cap is greater than the flow rate of electrolyte flowing through the first injection hole 11, the excess electrolyte will diffuse to the outside of the first injection hole 11. At this time, the electrolyte diffused to the outside of the first injection hole 11 can simultaneously enter the core through the multiple second injection holes 12, thereby assisting the first injection hole 11 in injection and further improving the electrolyte injection efficiency of the battery.
[0049] In this application, the sum of the cross-sectional areas of the plurality of second liquid injection holes 12 is set to S20. In actual use, if the sum of the cross-sectional areas of the plurality of second liquid injection holes 12 S20 is too small, it will affect the liquid injection efficiency of the battery, thereby reducing the battery production efficiency; if the sum of the cross-sectional areas of the plurality of second liquid injection holes 12 S20 is too large, it will reduce the effective welding area of the disk surface on the disk body 1 that can be used for welding with the positive electrode of the core, thereby affecting the safety performance of the battery.
[0050] Therefore, in this embodiment, the ratio S20 / S0 of the sum of the cross-sectional areas S20 of the multiple second injection holes 12 to the cross-sectional area S0 of the disk body 1 is set between 4% and 10%. This prevents the sum of the cross-sectional areas S20 of the multiple second injection holes 12 from being too small, which would affect the injection efficiency of the battery and thus improve the battery production efficiency. It also prevents the sum of the cross-sectional areas S20 of the multiple second injection holes 12 from being too large, which would reduce the effective welding area on the disk surface of the disk body 1 that can be used for welding to the positive electrode of the winding core, thereby ensuring the safety performance of the battery. Preferably, in this application, the ratio S20 / S0 is set to 6%.
[0051] Since the cross-sectional area S2 of a single second injection hole 12 is defined as the ratio S2 / S0 of the cross-sectional area S0 of the disk body 1 in the above embodiment, the number of second injection holes 12 provided on the disk body 1 can be determined in this embodiment based on the ratio S20 / S0 of the sum of the cross-sectional areas S20 of the plurality of second injection holes 12 to the cross-sectional area S0 of the disk body 1. For example, if the ratio S2 / S0 of the cross-sectional area S2 of a single second injection hole 12 to the cross-sectional area S0 of the disk body 1 is 2%, and the ratio S20 / S0 of the sum of the cross-sectional areas S20 of the plurality of second injection holes 12 to the cross-sectional area S0 of the disk body 1 is 6%, it can be determined that there are three second injection holes 12 provided on the disk body 1.
[0052] In this embodiment, the cylindrical lithium-ion battery also includes a core. The positive electrode tab of the core is flattened to form a flattened layer 5. The flattened layer 5 is welded to the disk body 1 to achieve the connection between the positive electrode of the core and the positive electrode current collector.
[0053] A third injection hole 51 is provided on the core. The third injection hole 51 penetrates the flattening layer 5 and is coaxial with the first injection hole 11. Therefore, the electrolyte mainly injected through the first injection hole 11 and auxiliaryly injected through the second injection hole 12 can enter the core through the third injection hole 51 to fill the gaps between the electrodes and the micropores of the separator, thereby completing the electrolyte injection of the battery.
[0054] In actual use, if the radius of the third injection hole 51 is too small, the electrolyte injected through the first injection hole 11 and the second injection hole 12 will flow into the core through the third injection hole 51 at a slow rate, thereby reducing the injection efficiency and thus reducing the battery production efficiency. If the radius of the third injection hole 51 is too large, the effective welding area of the flattened layer 5 that can be used for welding with the disk surface of the disk body 1 will be reduced, thereby causing the temperature at the welding line to rise and affecting the battery safety performance.
[0055] The radius of the third injection hole 51 is set to R10, and the cross-sectional area of the third injection hole 51 calculated with radius R10 is S10. In this application, the ratio S10 / S0 of the cross-sectional area S10 of the third injection hole 51 to the cross-sectional area S0 of the disk body 1 is set between 1% and 3%. This prevents the radius of the third injection hole 51 from being too small, which would affect the injection efficiency of the battery and thus improve the battery production efficiency. It also prevents the radius of the third injection hole 51 from being too large, which would affect the effective welding area available for welding the surface of the flattening layer 5 to the disk surface of the disk body 1, thereby ensuring the safety performance of the battery. Preferably, in this application, the ratio S10 / S0 is set to 2%.
[0056] As mentioned in the previous embodiments: the first injection hole 11 is located in the central region of the disc body 1, the second injection hole 12 is located outside the first injection hole 11, and the adhesive 4 extends from the outer peripheral surface of the disc body 1 to the upper surface of the disc body 1. Therefore, in this application, the position of the second injection hole 12 on the upper surface of the disc body 1 is located between the first injection hole 11 and the portion of the adhesive 4 extending on the upper surface of the disc body 1.
[0057] In actual use, if the distance between the first injection hole 11 and the second injection hole 12 is too close, the structural strength of the disk body 1 in the area between the first injection hole 11 and the second injection hole 12 will be too low. When the disk body 1 is welded to the flattening layer 5, it is easy to deform or break, thereby increasing the possibility of poor welding and causing the battery safety performance to decline.
[0058] If the distance between the first injection hole 11 and the second injection hole 12 is too far, the electrolyte that diffuses to the outside of the first injection hole 11 will enter the core through the second injection hole 12 too slowly, thus affecting the electrolyte injection efficiency of the battery.
[0059] Meanwhile, the outward movement of the second injection hole 12 will cause the distance between the second injection hole 12 and the part of the coating 4 extending on the upper surface of the disk body 1 to be too close. When the coating 4 is set, the part of the coating 4 extending on the upper surface of the disk body 1 will easily cover the second injection hole 12, causing the electrolyte to flow into the second injection hole 12 at a slower rate, which will also affect the electrolyte injection efficiency of the battery.
[0060] The minimum distance between the first injection hole 11 and the second injection hole 12 is set as L1, and the minimum distance between the second injection hole 12 and the portion of the coating 4 extending on the upper surface of the disc body 1 is set as L2.
[0061] Example 1:
[0062] In this embodiment, the ratio L1 of the minimum distance L1 between the first injection hole 11 and the second injection hole 12 to the radius R0 of the disk body 1 is set between 8% and 14%. This prevents the minimum distance L1 between the first injection hole 11 and the second injection hole 12 from being too small (the minimum distance L2 between the second injection hole 12 and the extension of the coating 4 on the upper surface of the disk body 1 is too large), which would affect the structural strength of the disk body 1 and thus ensure the safety performance of the battery.
[0063] Furthermore, to prevent the minimum distance L1 between the first injection hole 11 and the second injection hole 12 from being too large (and the minimum distance L2 between the second injection hole 12 and the portion of the coating 4 extending on the upper surface of the disc body 1 from being too small), which would affect the speed at which the electrolyte enters the core through the second injection hole 12, thereby improving the electrolyte injection efficiency of the battery. Preferably, in this application, the ratio L1 / R0 is set to 11%.
[0064] Example 2:
[0065] In this embodiment, the ratio L2 of the minimum distance L2 between the second injection hole 12 and the extension portion of the coating 4 on the upper surface of the disc body 1 to the radius R0 of the disc body 1 is set between 3% and 9%. This prevents the minimum distance L2 between the second injection hole 12 and the extension portion of the coating 4 on the upper surface of the disc body 1 from being too small (the minimum distance L1 between the first injection hole 11 and the second injection hole 12 from being too large), which would affect the speed at which the electrolyte enters the core through the second injection hole 12, thereby improving the electrolyte injection efficiency of the battery.
[0066] Furthermore, to prevent the minimum distance L2 between the second injection hole 12 and the extension portion of the coating 4 on the upper surface of the disk body 1 from being too large (the minimum distance L1 between the first injection hole 11 and the second injection hole 12 from being too small), which would affect the structural strength of the disk body 1, thereby ensuring the safety performance of the battery. Preferably, in this application, the ratio L2 / R0 is set to 6%.
[0067] In this embodiment, the positive current collector also includes a tail body 2 and a bending part 3. One end of the bending part 3 is connected to the disk body 1 and the other end is connected to the tail body 2. By bending the bending part 3, the tail body 2 is positioned above the disk body 1 and parallel to the upper surface of the disk body 1. Thus, the tail body 2 is welded to the lower end plate of the cap to achieve the connection between the positive current collector and the cap. That is, in this application, the positive current collector is welded to the flattened layer 5 of the positive electrode tab of the core through the disk body 1, and the tail body 2 is welded to the lower end plate of the cap to connect the positive electrode of the core to the cap, so that the cap leads out the positive electrode of the core.
[0068] In this application, the edge of the disc body 1 is provided with a concave notch, one end of the bent portion 3 is connected to the notch on the edge of the disc body 1, and the portion of the rubber coating 4 extending on the upper surface of the disc body 1 forms a complete ring structure. Therefore, the end of the bent portion 3 connected to the disc body 1 is located inside the portion of the rubber coating 4 extending on the upper surface of the disc body 1 and outside the first injection hole 11. That is, the end of the bent portion 3 connected to the disc body 1 is located between the first injection hole 11 and the portion of the rubber coating 4 extending on the upper surface of the disc body 1.
[0069] The minimum distance between one end of the bent portion 3 connecting to the disk body 1 and the first injection hole 11 is set to L4, and the minimum distance between one end of the bent portion 3 connecting to the disk body 1 and the extension portion of the rubber coating 4 on the upper surface of the disk body 1 is set to L5. In actual use, if the minimum distance L4 between one end of the bent portion 3 connecting to the disk body 1 and the first injection hole 11 is designed to be too small, that is, if the minimum distance L5 between one end of the bent portion 3 connecting to the disk body 1 and the extension portion of the rubber coating 4 on the upper surface of the disk body 1 is too large, it will cause the bent portion 3 to move excessively inward, increasing the area of the concave notch in the disk body 1, that is, reducing the flow area of the disk body 1, thereby increasing the heat generation of the battery and affecting the safety performance of the battery.
[0070] If the minimum distance L4 between the end of the bent part 3 connecting to the disc body 1 and the first liquid injection hole 11 is designed to be too large, that is, if the minimum distance L5 between the end of the bent part 3 connecting to the disc body 1 and the extension of the coating 4 on the upper surface of the disc body 1 is too small, the bent part 3 will move outward excessively. Since an insulating ring will be set on the coating 4 during the battery manufacturing process, if the bent part 3 moves outward excessively, the insulating ring will easily interfere with the bent part 3 when it is inserted from the tail body 2 downward, thereby increasing the difficulty of battery manufacturing and reducing production efficiency.
[0071] Example 3:
[0072] In this embodiment, the ratio L4 of the minimum distance L4 between one end of the bent portion 3 connecting to the disk body 1 and the first injection hole 11 to the radius R0 of the disk body 1, L4 / R0, is set between 25% and 34%. This prevents the bent portion 3 from moving excessively inward, reducing the current-carrying area of the positive electrode current collector and thus ensuring the safety performance of the battery. It also prevents the bent portion 3 from moving excessively outward, affecting the insertion of the insulating ring, thereby reducing the manufacturing difficulty of the battery and improving production efficiency. Preferably, in this application, the ratio L4 / R0 is set to 30%.
[0073] Example 4:
[0074] In this embodiment, the ratio L5 of the minimum distance L5 between the end of the bent portion 3 connecting to the disk body 1 and the extension portion of the adhesive 4 on the upper surface of the disk body 1, and the radius R0 of the disk body 1, is set between 13% and 20%. This prevents the bent portion 3 from moving excessively inward, reducing the current-carrying area of the positive electrode current collector and thus ensuring the safety performance of the battery. It also prevents the bent portion 3 from moving excessively outward, affecting the insertion of the insulating ring, thereby reducing the manufacturing difficulty of the battery and improving production efficiency. Preferably, in this application, the ratio L5 / R0 is set to 17%.
[0075] Specifically, in this embodiment, the radius R0 of the disk body 1 ranges from 9.74mm to 10.74mm. Therefore, in actual implementation, the value of R0 can be determined first based on its range, and then the value of S0 can be calculated based on the value of R0. The values of S3 / S0, S1 / S0, S2 / S0, S20 / S0, and S10 / S0 can be determined based on the ratios S3 / S0, S1 / S0, S20 / S0, and S10 / S0. Then, the values of L3, R1, R2, and R10 can be determined using the values of S3, S1, S2, and S10, respectively.
[0076] Based on the values of S2 and S20, the number of second injection holes 12 on the disk 1 can be determined; based on the ratios L1 / R0, L2 / R0, L4 / R0, and L5 / R0, the values of L1, L2, L4, and L5 can be determined respectively, thereby realizing the size design of this cylindrical lithium-ion battery. Preferably, in this application, R0 can be set to 10 mm.
[0077] The above-described contents can be implemented individually or in combination in various ways, and all such variations are within the protection scope of this utility model.
[0078] It should be noted that, in this document, relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes the element.
[0079] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.
Claims
1. A cylindrical lithium-ion battery, characterized in that: The device includes a positive current collector and an adhesive coating (4) disposed on the outer periphery of the positive current collector. The adhesive coating (4) is used to insulate the positive current collector from the battery casing. The positive current collector includes a disk body (1). Part of the adhesive coating (4) covers the outer periphery of the disk body (1), and another part extends on the upper surface of the disk body (1). The radius of the disk body (1) is R0, the cross-sectional area of the disk body (1) calculated with the radius R0 is S0, the width of the adhesive coating (4) extending on the upper surface of the disk body (1) is L3, the area of the adhesive coating (4) extending on the upper surface of the disk body (1) calculated with the width L3 is S3, and the ratio of the area of the adhesive coating (4) extending on the upper surface of the disk body (1) to the cross-sectional area S0 of the disk body (1), S3 / S0, is 44% to 56%.
2. A cylindrical lithium-ion battery as described in claim 1, characterized in that: The disc body (1) is provided with a first injection hole (11), the first injection hole (11) is coaxial with the disc body (1), the radius of the first injection hole (11) is R1, the cross-sectional area of the first injection hole (11) calculated with radius R1 is S1, and the ratio of the cross-sectional area S1 of the first injection hole (11) to the cross-sectional area S0 of the disc body (1) is 4% to 8%.
3. A cylindrical lithium-ion battery as described in claim 2, characterized in that: The disc body (1) is also provided with a second liquid injection hole (12). The second liquid injection hole (12) is distributed outside the first liquid injection hole (11). The radius of the second liquid injection hole (12) is R2. The cross-sectional area of the second liquid injection hole (12) calculated with radius R2 is S2. The ratio of the cross-sectional area S2 of the second liquid injection hole (12) to the cross-sectional area S0 of the disc body (1), S2 / S0, is 1.2% to 3.2%.
4. A cylindrical lithium-ion battery as described in claim 3, characterized in that: The second injection hole (12) is provided on the disc body (1) in multiple ways. The ratio of the sum of the cross-sectional areas S20 of the multiple second injection holes (12) to the cross-sectional area S0 of the disc body (1) is 4% to 10%.
5. A cylindrical lithium-ion battery as described in claim 2, characterized in that: The cylindrical lithium-ion battery also includes a core, the positive electrode tab of which is flattened to form a flattened layer (5), the flattened layer (5) is connected to the disc body (1), the core is provided with a third liquid injection hole (51) penetrating the flattened layer (5), the third liquid injection hole (51) is coaxial with the first liquid injection hole (11), the radius of the third liquid injection hole (51) is R10, the cross-sectional area of the third liquid injection hole (51) calculated with radius R10 is S10, and the ratio of the cross-sectional area S10 of the third liquid injection hole (51) to the cross-sectional area S0 of the disc body (1) is S10 / S0, which is 1% to 3%.
6. A cylindrical lithium-ion battery as described in claim 3, characterized in that: The minimum distance L1 between the first injection hole (11) and the second injection hole (12) is 8% to 14% of the ratio of the radius R0 of the disc body (1) to the ratio L1 / R0.
7. A cylindrical lithium-ion battery as described in claim 3, characterized in that: The minimum distance L2 between the second injection hole (12) and the extension portion of the coating (4) on the upper surface of the disc (1) is 3% to 9% of the ratio of L2 / R0 to the radius R0 of the disc (1).
8. A cylindrical lithium-ion battery as described in claim 2, characterized in that: The positive electrode current collector also includes a tail body (2) for connecting to the lower end plate of the cap, and a bent part (3) connected at one end to the disk body (1) and at the other end to the tail body (2); the minimum distance L4 between the bent part (3) and the first injection hole (11) is 25% to 34% of the ratio of the minimum distance L4 between the end of the bent part (3) connected to the disk body (1) and the radius R0 of the disk body (1).
9. A cylindrical lithium-ion battery as described in claim 2, characterized in that: The positive current collector also includes a tail body (2) for connecting to the lower end plate of the cap, and a bent part (3) connected at one end to the disk body (1) and at the other end to the tail body (2); the minimum distance L5 between the end of the bent part (3) connected to the disk body (1) and the extension of the rubber coating (4) on the upper surface of the disk body (1) is 13% to 20% of the radius R0 of the disk body (1).
10. A cylindrical lithium-ion battery as described in claim 1, characterized in that: The radius R0 of the disk body (1) ranges from 9.74 mm to 10.74 mm.