Cylindrical battery

Abstract

The present application discloses a cylindrical battery, comprising a battery cell and an electrically conductive connector. The electrically conductive connector is recessed to form a welding groove, and the portion of the electrically conductive connector located in the welding groove is electrically connected to the battery cell. Compared with the related art, the present application uses the mode of forming a welding groove in an electrically conductive connector, the electrically conductive connector can be recessed toward a negative electrode tab of the battery cell to form the welding groove, and the welding groove is configured to be welded to the negative electrode tab of the battery cell. Thus, the welding groove is closer to the tab, helping to shorten the welding path and achieve electrical connection between the electrically conductive connector and the negative electrode tab of the battery cell. In this way, welding steps can be simplified without additionally providing a current collecting disc, thereby saving the internal installation space of the cylindrical battery.

Description

A cylindrical battery

[0001] This application claims priority to Chinese Patent Application No. 202423221037.5, filed with the Chinese Patent Office on December 25, 2024, the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application relates to the field of battery technology, and more particularly to a cylindrical battery. Background Technology

[0003] The negative electrode tab of a battery is an important component that connects the internal negative electrode material of the battery to the external circuit. The connection between the negative electrode tab, current collector, and top cover is a key part to ensure the stability of the internal structure and the efficiency of current conduction of the battery. Technical issues

[0004] The negative electrode connection of the relevant cells is mostly achieved by welding the negative electrode tab and the negative electrode current collector, and then welding the negative electrode current collector to the top cover / shell. The welding method is relatively complicated, which increases the internal space of the battery, making it difficult to transport and store the battery. In addition, there are many parts, and the structural design is relatively cumbersome. Technical solutions

[0005] In a first aspect, this application provides a cylindrical battery, including a cell and a conductive connector, wherein the conductive connector is recessed to form a welding groove, and the portion of the conductive connector located in the welding groove is electrically connected to the cell. Beneficial effects

[0006] The beneficial effects provided by this application are as follows: This application provides a cylindrical battery, including a cell and a conductive connector. The conductive connector has a recessed welding groove, and the portion of the conductive connector located in the welding groove is electrically connected to the cell. Compared with related technologies, this application uses a conductive connector with a welding groove. The conductive connector can form a welding groove towards the negative electrode tab of the cell. The welding groove is set to weld to the negative electrode tab of the cell. In this way, the welding groove is closer to the tab, which helps to shorten the welding path and achieve electrical connection between the conductive connector and the negative electrode tab of the cell. This design simplifies the welding steps, eliminates the need for an additional current collector, and saves internal installation space in the cylindrical battery. Attached Figure Description

[0007] Figure 1 is a schematic diagram of the assembly structure of the cylindrical battery provided in an embodiment of this application;

[0008] Figure 2 is an exploded structural diagram of the cylindrical battery provided in an embodiment of this application;

[0009] Figure 3 is a cross-sectional schematic diagram of the cylindrical battery provided in an embodiment of this application;

[0010] Figure 4 is a magnified view of part A in Figure 3;

[0011] Figure 5 is a cross-sectional schematic diagram of the conductive connector provided in an embodiment of this application;

[0012] Figure 6 is a schematic diagram of the structure of the conductive connector provided in the embodiment of this application.

[0013] Explanation of icon numbers:

[0014] Housing 20, second limiting groove 201, battery cell 30, conductive connector 10, first conductive component 12, substrate 121;

[0015] Groove 122, first limiting groove 124, explosion-proof groove 128, liquid injection hole 129, protrusion 123, welding groove 125;

[0016] 126. Channel wall 127. Bottom wall 127. Through channel 120. Second conductive component 14. First plate 141. Second plate 143. Third plate 145.

[0017] Implementation methods of this application

[0018] Please refer to Figure 1. An embodiment of this application provides a cylindrical battery, including a cell 30 and a conductive connector 10. The conductive connector 10 is recessed to form a welding groove 125, and the portion of the conductive connector 10 located in the welding groove 125 is electrically connected to the cell 30.

[0019] In practical applications, the conductive connector 10 is typically recessed towards the cell 30 to form a welding groove 125. The portion of the welding groove 125 near the cell 30 is electrically connected to the cell 30. Specifically, the welding groove 125 is electrically connected to the tab of the cell 30. The cell 30 has a positive tab and a negative tab. The positive tab usually needs to be connected to a positive current collector, and the negative tab usually needs to be connected to a negative current collector. The conductive connector 10 can form a welding groove 125 towards the negative tab of the cell 30. The welding groove 125 is configured to be welded to the negative tab of the cell 30. In this way, the welding groove 125 is closer to the tab, which helps to shorten the welding path and achieve an electrical connection between the conductive connector 10 and the negative tab of the cell 30. This configuration simplifies the welding steps, eliminates the need for an additional current collector, and saves internal installation space in the cylindrical battery.

[0020] It should be noted that during battery manufacturing, the negative electrode tab is typically welded to a current collector (also called a current collector or busbar) rather than directly to the negative electrode material of the cell 30. The main function of the current collector is to collect the current from the cell 30, ensuring that the current can be efficiently and safely conducted to the external circuit. This welding process is relatively cumbersome, and welding the current collector inside the battery increases the internal space, increases material costs, and is detrimental to battery transportation and storage. This application uses a conductive connector 10 with a welding groove 125 to weld the negative electrode tab, eliminating the need for a current collector and effectively reducing battery production costs.

[0021] It is understood that in some embodiments, the conductive connector 10 can also be used to weld the positive electrode tab, and this application does not limit this.

[0022] Referring to Figure 2, the conductive connector 10 includes a first conductive element 12 and a second conductive element 14. The first conductive element 12 includes a substrate 121 and a protrusion 123. The protrusion 123 is recessed relative to the substrate 121 to form a welding groove 125. The second conductive element 14 covers the side of the protrusion 123 away from the welding groove 125. The second conductive element 14 is electrically connected to the battery cell 30.

[0023] In practical applications, the substrate 121 is connected to the outer periphery of the protrusion 123. The protrusion 123 is recessed towards the cell 30 to form a welding groove 125. The second conductive member 14 is wrapped around the side of the protrusion 123 near the cell 30. The second conductive member 14 and the protrusion 123 are electrically connected, and the second conductive member 14 is also electrically connected to the tab of the cell 30, realizing the conductive connection between the tab and the conductive connector 10. With this configuration, the protrusion 123 is closer to the cell 30, and the second conductive member 14 is easier to connect to the tab of the cell 30, shortening the welding distance and saving space between the conductive connector 10 and the cell 30, thereby saving battery volume.

[0024] In one embodiment, the materials of the first conductive element 12 and the second conductive element 14 are different. In practical applications, the conductive connector 10, besides serving to achieve electrical connection with the tabs of the battery cell 30, can usually act as a top cover, needing to be connected to the battery casing 20 to form a complete battery structure. Therefore, the first conductive element 12 can mainly function as a top cover, meaning it needs to be connected to the casing 20. Thus, the material of the first conductive element 12 can be similar to that of the casing 20. The main function of the battery casing 20 is to protect the internal battery cell 30 from external environmental influences, while providing structural support and electrical insulation; therefore, it is typically made of either metal or non-metal. The second conductive element 14 is mainly used for electrical connection to the tabs of the battery cell 30, and it is made of a material with good conductivity, such as copper or aluminum. Using a material similar to the casing 20 for the first conductive element 12 facilitates the connection between them; for example, they have the same melting point, making welding easier. The material of the second conductive element 14 can be the same as that of the tab, which has good conductivity and is easier to weld, ensuring that the current can be conducted to the external circuit efficiently and safely.

[0025] By using a first conductive element 12 and a second conductive element 14 made of different materials, the connection between the conductive connector 10 and the housing 20 is made easier, while ensuring the ease of welding the conductive connector 10 and the electrode tab, thus saving material costs.

[0026] Referring to Figures 3 and 4, the protrusion 123 includes a groove wall 126, which is connected to the substrate 121 and extends away from the substrate 121. A second conductive element 14 covers the groove wall 126, and the second conductive element 14 and the groove wall 126 surround to form a welding groove 125.

[0027] In practical applications, the groove wall 126 mainly serves as the connection point between the first conductive element 12 and the second conductive element 14. The groove wall 126 extends towards the battery cell 30, and the second conductive element 14 is connected to the side of the groove wall 126 facing the battery cell 30 to fix the first conductive element 12 and the second conductive element 14, while shortening the distance between the second conductive element 14 and the electrode tab of the battery cell 30. The second conductive element 14 and the groove wall 126 form a welding groove 125, which allows the second conductive element 14 to be exposed to the outside. When welding the second conductive element 14 and the electrode tab, the exposed second conductive element 14 can reduce the thickness required for welding, making it easier to weld the electrode tab. At the same time, the groove wall 126 can provide support and improve the stability of the weld.

[0028] Referring again to Figure 4, the protrusion 123 also includes a bottom wall 127, and groove walls 126 are disposed at opposite ends of the bottom wall 127. The groove walls 126 and the bottom wall 127 together form a welding groove 125. In practical applications, the second conductive element 14 is connected to the protrusion 123. The protrusion 123 also includes the bottom wall 127. The second conductive element 14 simultaneously covers the bottom wall 127 and the groove wall 126 on the side near the battery cell 30. The bottom wall 127 increases the connection area between the second conductive element 14 and the first conductive element 12, thereby improving the connection stability between the first conductive element 12 and the second conductive element 14.

[0029] Referring again to Figure 4, a through groove 120 is provided on the bottom wall 127, and part of the second conductive element 14 is opposite to the through groove 120.

[0030] In practical applications, a through groove 120 is formed in the bottom wall 127, and part of the second conductive element 14 is exposed in the through groove 120. This results in a smaller welding thickness at the through groove 120, which facilitates welding the exposed part of the second conductive element 14 to the electrode tab. This method achieves both welding the electrode tab to the second conductive element 14 and retaining part of the bottom wall 127 by forming a through groove 120, which helps to increase the structural strength of the first conductive element 12 and thus the structural strength of the conductive connector 10.

[0031] In one embodiment, there are multiple through slots 120. Multiple through slots 120 can be formed along the outer periphery of the bottom wall 127, so that the exposed area of ​​the second conductive element 14 is larger, thereby increasing the welding area and enhancing the welding stability of the electrode tab and the second conductive element 14.

[0032] In one embodiment, the width of the bottom wall 127 is B1, and the width of the through groove 120 is B2, where 1 ≥ B2 / B1 ≥ 0.5. In practical applications, the wider the width of the through groove 120 on the bottom wall 127, the wider the exposed width of the second conductive component 14, which is beneficial for increasing the welding area and improving welding convenience. At the same time, the width of the through groove 120 also affects the structural strength of the first conductive component 12 itself or the connection area between the first conductive component 12 and the second conductive component 14. Therefore, the width of the through groove 120 is usually set between 0.5 and 1 times the width of the bottom wall 127, for example, B2=B1, B2=0.6B1, B2=0.7B1, etc. Through grooves 120 within this range satisfy the welding area requirements and ensure the structural strength of the first conductive component 12 and the second conductive component 14.

[0033] In one embodiment, a plurality of through slots 120 are spaced apart along the circumferential direction of the welding groove 125; this increases the exposed area of ​​the second conductive element 14, while the spaced arrangement ensures that the area of ​​a single through slot 120 is not too large, thus avoiding damage to the structural strength of the first conductive element 12 itself.

[0034] In one embodiment, the area of ​​the second conductive element 14 and the through groove 120 relative to each other is S1 square millimeters, where 500 ≥ S1 ≥ 40. For example, S1 can be 40 square millimeters, 60 square millimeters, 70 square millimeters, 80 square millimeters, 90 square millimeters, or 100 square millimeters, etc. S1 is the area of ​​the through groove 120, which is the exposed area of ​​the second conductive element 14. Within this range, S1 can ensure that the welding area is large enough and that the structural strength of the first conductive element 12 and the second conductive element 14 is guaranteed, so as to avoid damage to the conductive connector 10 caused by external impact during transportation or operation.

[0035] In one embodiment, the projected area of ​​the first conductive element 12 in its thickness direction is S0, where 0.7S0 ≥ S1 ≥ 0.05S0. In practical applications, S1 is the exposed area of ​​the second conductive element 14. If the exposed area of ​​the second conductive element 14 is too large, it can easily affect the performance of the connection interface between the first conductive element 12 and the second conductive element 14, increasing costs; if the exposed area of ​​the second conductive element 14 is too small, it affects welding and results in poor current carrying capacity. Therefore, setting the exposed area of ​​the second conductive element 14 between 0.05 and 0.7 times the projected area of ​​the first conductive element 12 can ensure both current carrying capacity and the stability of the connection interface. For example, values ​​such as S1 = 0.05S0, S1 = 0.1S0, S1 = 0.2S0, S1 = 0.3S0, S1 = 0.4S0, S1 = 0.5S0, S1 = 0.6S0, and S1 = 0.7S0 are used.

[0036] Referring again to Figure 4, in one embodiment, the groove wall 126 and the substrate 121 are smoothly connected, and the radius of the corner at the connection between the groove wall 126 and the substrate 121 is α1 degrees, where 2 ≥ α1 ≥ 0.5. In practical applications, the first conductive element 12 can typically be formed with a welding groove 125 using a stamping process. This process creates a radius at the connection between the groove wall 126 and the substrate 121 to prevent cracks or breaks in the material during the forming process, ensuring smooth material flow and reducing stress concentration. The radius α1 can typically be 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, 2.0, etc.

[0037] In one embodiment, the groove wall 126 and the bottom wall 127 are smoothly connected, and the fillet at the connection between the groove wall 126 and the bottom wall 127 is α2 degrees, where 2 ≥ α2 ≥ 0.5. In practical applications, when forming the welding groove 125, a certain fillet radius is usually set at the corner to prevent the material from breaking during the forming process. Therefore, a fillet α2 is also formed at the connection between the groove wall 126 and the bottom wall 127. Typically, the fillet α2 can take values ​​such as 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, and 2.0.

[0038] Referring again to Figure 4, the second conductive element 14 includes a first plate 141 and a second plate 143. The second plate 143 is disposed at at least one end of the first plate 141. The first plate 141 and the second plate 143 cover the side of the protrusion 123 away from the welding groove 125. The first plate 141 is connected to the protrusion 123 in the thickness direction of the first conductive element 12.

[0039] In practical applications, the first plate 141 is connected to the bottom wall 127 of the protrusion 123. The bottom wall 127 is a horizontal plane. The first plate 141 is the main part to be welded to the electrode lug. Since the bottom wall 127 is a horizontal plane, the first plate 141 is also a horizontal plane. Therefore, horizontal welding can be used when welding the first plate 141 and the electrode lug, which makes the shape of the weld more uniform, reduces the risk of molten pool sagging or flowing, and avoids uneven weld surface or weld beads.

[0040] Referring again to Figure 4, the second conductive element 14 includes a third plate 145, which is connected to the end of the second plate 143 away from the first plate 141, and the third plate 145 is connected to the substrate 121.

[0041] In practical applications, the second plate 143 is connected to the first plate 141 and the third plate 145 respectively. The first plate 141 is connected to the bottom wall 127 of the protrusion 123, the second plate 143 is connected to the groove wall 126 of the protrusion 123, and the third plate 145 is connected to the substrate 121. The connection between the first plate 141, the second plate 143 and the third plate 145 strengthens the connection stability of the first conductive element 12 and the second conductive element 14.

[0042] Referring to Figure 5, the third plate 145 and the substrate 121 are stacked. This arrangement increases the thickness of the conductive connector 10 on both sides of the welding groove 125. Since the welding groove 125 is the part for welding tabs, the substrate 121 on both sides of the welding groove 125 is easily affected by the high temperature and welding force during welding. In order to avoid damage to the substrate 121, the third plate 145 and the substrate 121 are stacked to increase the thickness of this part and avoid affecting the structural strength of the conductive connector 10 during welding.

[0043] Referring again to Figure 5, a step is formed between the third plate 145 and the substrate 121. In one embodiment, the second conductive element 14 and the first conductive element 12 can be formed by a pressing process. During the pressing process, a step is formed between the third plate 145 and the substrate 121. The step formed by the pressing process helps prevent the part from springing back after unloading. Due to the presence of the step, certain areas of the part are fixed in the mold, reducing the elastic recovery of the material and ensuring a more stable final shape of the part; at the same time, the step can increase the thickness of the substrate 121.

[0044] Referring again to Figure 4, a groove 122 is provided on one side of the substrate 121, and the end of the third plate 145 is embedded in the groove 122. This arrangement can effectively improve the connection strength between the third plate 145 and the substrate 121, and improve the connection stability between the first conductive element 12 and the second conductive element 14.

[0045] Referring again to Figure 4, the groove 122 has a fixed cavity and an opening communicating with the fixed cavity. The third plate 145 passes through the opening into the fixed cavity. The maximum width of the fixed cavity is D1, and the width of the opening is D2. 1.5≥D1 / D2>1.

[0046] In practical applications, the third plate 145 extends into the groove 122 from the opening and connects with the substrate 121. The width of the opening is usually smaller than the width of the fixing cavity within the groove 122. This design allows for a smaller opening, which strengthens the connection stability between the third plate 145 and the substrate 121 and prevents the third plate 145 from detaching. Conversely, a wider fixing cavity allows for a larger volume of the third plate 145 extending into the cavity, further enhancing the connection stability between the third plate 145 and the substrate 121. For example, D1 can be set between D2 and 1.5 times D2, where D1 = 1.5D2. Within this range, D1 avoids the groove being too large, thus affecting the structural strength of the substrate 121 itself.

[0047] Referring again to Figure 4, the first plate 141 and the second plate 143 are smoothly connected, and the fillet at the connection point is α3, where 2 ≥ α3 ≥ 0.5. The smooth fillet at the connection point of the first plate 141 and the second plate 143 avoids stress concentration at the connection point when forming the second conductive component 14, thus increasing the structural strength of the second conductive component 14. Typically, the fillet α3 can be taken as values ​​such as 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, or 2.0.

[0048] Referring again to Figure 4, the second plate 143 and the third plate 145 are smoothly connected. The fillet at the connection between the second plate 143 and the third plate 145 is α4, where 2 ≥ α4 ≥ 0.5. The fillet α4 can take values ​​such as 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.5, and 2.0. The rounded fillet at the connection between the second plate 143 and the third plate 145 can avoid stress concentration at the connection point and prevent material damage during the molding process of the second conductive component 14.

[0049] Referring to Figure 5, the thickness of the first plate 141 is L1 mm, where 3 ≥ L1 ≥ 0.1. For example, L1 can be values ​​such as 0.1, 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, and 2.0. Within this range, L1 ensures a certain structural strength while avoiding excessive thickness, which could affect the performance of penetration welding.

[0050] Referring again to Figure 5, the thickness of substrate 121 is L2, where 1.2L2 ≥ L1 ≥ 0.4L2. For example, L1 = 0.4L2, L1 = L2, or L1 = 1.2L2, where L1 is the thickness of the first plate 141 and L2 is the thickness of substrate 121. Since substrate 121 is located on the outside, its thickness should generally not be too small to avoid deformation due to external impacts. At the same time, substrate 121 should not be too thick, otherwise it will affect the welding effect; if substrate 121 is too thin, it will affect the structural strength of the first conductive element 12 itself. Therefore, the thickness ratio of substrate 121 to the first plate 141 is limited to this range to ensure both welding effect and structural strength.

[0051] Referring again to Figure 4, the thickness of the portion connecting the protrusion 123 and the first plate 141 is L3, where 0.5L1≥L3≥0. Specifically, L3 refers to the thickness of the bottom wall 127 of the protrusion 123. The thickness of the bottom wall 127 is usually less than 0.5 times L1, meaning that the thickness of the bottom wall 127 is less than 0.5 times that of the first plate 141. When welding the first plate 141 and the tab, the welding process needs to penetrate the bottom wall 127. If the bottom wall 127 is too thick, it will affect the penetration welding effect. Therefore, the thickness of the bottom wall 127 is limited to this range, for example, L3=0.1L1, L3=0.2L1, L3=0.3L1, L3=0.4L1, L3=0.5L1. In special cases, L3 can be 0, that is, the bottom wall 127 is not set, and the first plate 141 is completely exposed to the outside, which can provide the maximum welding area.

[0052] Referring again to Figure 4, the distance between the side of the bottom wall 127 away from the second conductive element 14 and the top surface of the substrate 121 is H1, and the distance between the side of the second conductive element 14 away from the bottom wall 127 and the top surface of the substrate 121 is H2, where 0.2H2≤H1≤5H2.

[0053] In practical applications, along the thickness direction, the side of the substrate 121 furthest from the cell 30 is designated as the upper side, and the side of the substrate 121 closest to the cell 30 is designated as the lower side. H1 represents the distance from the top surface of the substrate 121 to the top surface of the bottom wall 127, and H2 represents the distance from the top surface of the conductive connector 10 to the bottom surface of the conductive connector 10. The larger H1 is, the deeper the welding groove 125 is. On the one hand, an excessively deep welding groove 125 will affect the welding operation, and on the other hand, an excessively deep welding groove 125 is too close to the tab, which may cause the tab to contact the first conductive element 12, resulting in a short circuit. The larger H2 is, the farther the substrate 121 is from the tab. H1 is limited to between 0.2 times H2 and 5 times H2 to avoid the substrate 121 being too far from the tab, which would result in too large an internal space in the battery and affect the battery size. At the same time, it also avoids the substrate 121 being too close to the tab and prevents the substrate 121 from contacting the tab. For example, values ​​such as H1=0.2H2, H1=0.3H2, H1=0.4H2, H1=0.5H2, H1=0.6H2, H1=0.2H2, H1=0.7H2, H1=0.8H2, H1=0.9H2, H1=1.0H2, H1=1.1H2, H1=1.2H2, H1=1.3H2, etc.

[0054] Referring to Figure 5, the substrate 121 has an explosion-proof groove 128 surrounding a welding groove 125, which is located within the area enclosed by the explosion-proof groove 128. In practical applications, the explosion-proof groove 128 provides a controlled venting channel to promptly release gases and heat generated inside the battery, preventing safety accidents caused by excessive pressure or temperature. Therefore, the perimeter of the explosion-proof groove 128 should be relatively long to ensure sufficient venting channels and prevent gas accumulation. The welding groove 125 is mainly used for welding tabs, and its main function is to collect current. Therefore, the perimeter of the welding groove 125 is usually smaller than that of the explosion-proof groove 128, hence the welding groove 125 is located within the area enclosed by the explosion-proof groove 128.

[0055] Referring again to Figure 5, the distance between the explosion-proof groove 128 and the welding groove 125 is L4 mm, where 10 ≥ L4 ≥ 1. L4 represents the distance between the explosion-proof groove 128 and the welding groove 125. If the explosion-proof groove 128 is too close to the welding groove 125, the temperature and pressure during welding can easily affect and damage the explosion-proof groove 128. However, if the explosion-proof groove 128 is too far from the welding groove 125, the battery size increases, affecting the battery's energy density and hindering transportation and storage. Therefore, L4 can be limited to between 1 mm and 10 mm, for example, L4=1, L4=2, L4=3, L4=4, L4=5, L4=6, L4=7, L4=8, L4=9, L4=10, etc. This range of L4 avoids affecting the stability of the explosion-proof groove 128 during welding and also limits the battery size, preventing it from becoming too large.

[0056] Referring again to Figure 5, the substrate 121 has a liquid injection hole 129, and the welding groove 125 surrounds the liquid injection hole 129. The liquid injection hole 129 is located in the area formed by the welding groove 125.

[0057] In practical applications, the location of the injection hole 129 within the explosion-proof groove 128 better ensures the battery's sealing. After injection, the injection hole 129 is typically sealed (e.g., through welding, plugging, or other sealing methods). If the injection hole 129 is located within the explosion-proof groove 128, the area between the sealed injection hole 129 and the explosion-proof groove 128 forms an additional sealing layer, preventing electrolyte leakage. Simultaneously, during the injection process, electrolyte may leak from the injection hole 129 due to improper operation or pressure fluctuations. If the injection hole 129 is located within the explosion-proof groove 128, even if a small amount of electrolyte leaks, it will be absorbed or guided to a safe area by the space within the explosion-proof groove 128, preventing direct leakage to the outside of the battery and reducing safety hazards.

[0058] Referring again to Figure 5, the distance between the injection hole 129 and the welding groove 125 is L5 mm, where 15 ≥ L5 ≥ 2. L5 represents the distance between the injection hole 129 and the welding groove 125. If the distance is too close, the injection hole 129 is easily affected by the high temperature of welding, which may damage the sealing performance of the injection hole 129. If the distance is too far, the size of the battery will be increased. Therefore, L5 is limited to between 2 mm and 15 mm to avoid the distance being too close or too far. For example, L5 is 2 mm, 3 mm, 4 mm, 5 mm, 6 mm, 7 mm, 8 mm, 9 mm, 10 mm, 11 mm, 12 mm, 13 mm, 14 mm, and 15 mm.

[0059] Referring to Figures 3 and 4, the battery cell 30 is cylindrical with a radius of R1. The shortest distance between the protrusion 123 and the central axis of the battery cell 30 is R2, where 0.85R1≥R2≥0.15R1.

[0060] In practical applications, the ratio of R2 to R1 limits the distance between the protrusion 123 and the center of the battery cell 30. If the distance between the protrusion 123 and the center of the battery cell 30 is too close, the perimeter of the welding groove 125 will be small, the welding trajectory will be short, and the current carrying capacity will be poor. If the distance between the protrusion 123 and the center of the battery cell 30 is too far, the welding groove 125 will be far away from the center of the battery cell 30, resulting in fewer electrode layers corresponding to the welding groove 125, which will affect the welding effect between the second conductive element 14 and the electrode. Therefore, the ratio of R2 to R1 is limited to between 0.15 and 0.85, such as R2=0.15R1, R2=0.2R1, R2=0.25R1, or R2=0.85R1, to avoid the welding groove 125 being too long or too short from the center of the battery cell 30.

[0061] Referring again to Figures 3 and 4, the cylindrical battery also includes a housing 20, in which the battery cell 30 is assembled. The edge of the conductive connector 10 is provided with a first limiting groove 124, and the edge of the housing 20 is inserted into the first limiting groove 124.

[0062] In practical applications, the battery cell 30 is installed inside the housing 20, then the second conductive element 14 and the electrode tab are welded together. Finally, the first conductive element 12 of the conductive connector 10 needs to be fixedly connected to the housing 20 to complete the assembly of the entire battery. The first conductive element 12 has a first limiting groove 124, which facilitates positioning of the housing 20 during assembly and improves assembly efficiency. The first conductive element 12 and the housing 20 can be fixed together by welding or other methods.

[0063] Referring again to Figure 4, the cylindrical battery also includes a housing 20, in which the battery cell 30 is assembled. The edge of the housing 20 is provided with a second limiting groove 201, and the edge of the conductive connector 10 is inserted into the second limiting groove 201.

[0064] In practical applications, in addition to the first limiting groove 124 on the conductive connector 10, a second limiting groove 201 can also be provided on the housing 20. The second limiting groove 201 is beneficial for positioning the first conductive component 12 during assembly, achieving a similar effect to the above.

[0065] Referring again to Figure 4, the cylindrical battery also includes a casing 20, in which the cell 30 is assembled. The distance between the protrusion 123 and the inner surface of the casing 20 is R3, and the diameter of the casing 20 is R4, where 0.4R4≥R3≥0.15R4. R3 represents the length of the protrusion 123 from the inner surface of the casing 20, and R4 is the diameter of the casing 20. The larger R3 is, the farther the protrusion 123 is from the inner surface of the casing 20. In other words, the second conductive element 14 can be farther away from the inner surface of the casing 20. This effectively avoids the second conductive element 14 from connecting with the inner surface of the casing 20, thus preventing the second conductive element 14 from affecting the electrical connection between the second conductive element 14 and the tab. However, a larger R3 also means that the protrusion 123 is closer to the center of the cell 30, which will shorten the welding trajectory and affect the current carrying capacity. Therefore, R3 should be limited to between 0.15 times R4 and 0.4 times R4, such as R3=0.3R4, R3=0.2R4, R3=0.1R4, R3=0.15R4, etc. R3 within this range can ensure that the second conductive element 14 does not contact the inner surface of the housing 20, and can also ensure that the welding groove 125 is not too close to the center of the cell 30, thereby affecting the current carrying capacity.

Claims

1. A cylindrical battery, comprising: Battery cell; A conductive connector has a recessed welding groove, and the portion of the conductive connector located in the welding groove is electrically connected to the battery cell.

2. The cylindrical battery according to claim 1, wherein, The conductive connector includes: A first conductive element includes a substrate and a protrusion, the protrusion being recessed relative to the substrate to form a welding groove; and The second conductive element covers the side of the protrusion away from the welding groove, and the second conductive element is electrically connected to the battery cell.

3. The cylindrical battery according to claim 2, wherein, The materials of the first conductive element and the second conductive element are different.

4. The cylindrical battery according to claim 2, wherein, The protrusion includes a groove wall that is connected to the substrate and extends away from the substrate. The second conductive element covers the groove wall, and the second conductive element and the groove wall together form the welding groove.

5. The cylindrical battery according to claim 4, wherein, The protrusion includes a bottom wall, and the groove wall is disposed at opposite ends of the bottom wall, the groove wall and the bottom wall forming the welding groove.

6. The cylindrical battery according to claim 5, wherein, The bottom wall has a through groove, and part of the second conductive element is opposite to the through groove.

7. The cylindrical battery according to claim 6, wherein, The width of the bottom wall is B1, and the width of the through groove is B2, where 1 ≥ B2 / B1 ≥ 0.

5.

8. The cylindrical battery according to claim 6, wherein, The number of through slots is multiple.

9. The cylindrical battery according to claim 8, wherein, The plurality of through slots are spaced apart along the circumferential direction of the welding groove.

10. The cylindrical battery according to claim 6, wherein, The area of ​​the second conductive element and the through groove opposite each other is S1 square millimeters, where 500 ≥ S1 ≥ 40.

11. The cylindrical battery according to claim 10, wherein, The projected area of ​​the first conductive element in its thickness direction is S0, 0.7S0≥S1≥0.05S0.

12. The cylindrical battery according to claim 4, wherein, The groove wall and the substrate are smoothly connected, and the fillet at the connection between the groove wall and the substrate is α1,2≥α1≥0.

5.

13. The cylindrical battery according to claim 5, wherein, The groove wall and the bottom wall are smoothly connected, and the fillet at the connection between the groove wall and the bottom wall is α2,2≥α2≥0.

5.

14. The cylindrical battery according to claim 2, wherein, The second conductive element includes a first plate and a second plate. The second plate is disposed at at least one end of the first plate. The first plate and the second plate cover the side of the protrusion away from the welding groove. The first plate is connected to the protrusion in the thickness direction of the first conductive element.

15. The cylindrical battery according to claim 14, wherein, The second conductive element includes a third plate, the third plate and the second plate being connected at the ends away from the first plate, and the third plate being connected to the substrate.

16. The cylindrical battery according to claim 15, wherein, The third plate and the substrate are stacked together.

17. The cylindrical battery of claim 16, wherein, A step is formed between the third plate and the substrate.

18. The cylindrical battery of claim 16, wherein, A groove is provided on one side of the substrate, and the end of the third plate is embedded in the groove.

19. The cylindrical battery of claim 18, wherein, The groove has a fixed cavity and an opening communicating with the fixed cavity. The third plate passes through the opening into the fixed cavity. The maximum width of the fixed cavity is D1, and the width of the opening is D2. 1.5 ≥ D1 / D2 > 1.

20. The cylindrical battery of claim 14, wherein, The first plate and the second plate are smoothly connected, and the fillet at the connection between the first plate and the second plate is α3,2≥α3≥0.

5.

21. The cylindrical battery of claim 15, wherein, The second plate and the third plate are smoothly connected, and the fillet at the connection between the second plate and the third plate is α4,2≥α4≥0.

5.

22. The cylindrical battery of claim 14, wherein, The thickness of the first plate is L1 mm, and 3 ≥ L1 ≥ 0.

1.

23. The cylindrical battery of claim 22, wherein, The thickness of the substrate is L2, where 1.2L2≥L1≥0.4L2.

24. The cylindrical battery of claim 22, wherein, The thickness of the portion of the protrusion that connects to the first plate is L3, 0.5L1≥L3≥0.

25. The cylindrical battery of claim 5, wherein, The distance between the side of the bottom wall away from the second conductive element and the top surface of the substrate is H1, and the distance between the side of the second conductive element away from the bottom wall and the top surface of the substrate is H2, where 0.2H2≤H1≤5H2.

26. The cylindrical battery according to any one of claims 2 to 25, wherein The substrate has an explosion-proof groove, which surrounds the welding groove and is located within the area enclosed by the explosion-proof groove.

27. The cylindrical battery of claim 26, wherein, The distance between the explosion-proof groove and the welding groove is L4 mm, and 10 ≥ L4 ≥ 1.

28. The cylindrical battery of any one of claims 2 to 25, wherein, The substrate has a liquid injection hole, and the welding groove surrounds the liquid injection hole, with the liquid injection hole located within the area enclosed by the welding groove.

29. The cylindrical battery of claim 28, wherein, The distance between the injection hole and the welding groove is L5 mm, where 15 ≥ L5 ≥ 2.

30. The cylindrical battery according to any one of claims 2 to 25, wherein, The battery cell is cylindrical with a radius of R1. The shortest distance between the protrusion and the central axis of the battery cell is R2, where 0.85R1≥R2≥0.15R1.

31. The cylindrical battery according to any one of claims 1 to 25, wherein The cylindrical battery also includes a housing, the battery cell is assembled in the housing, the edge of the conductive connector is provided with a first limiting groove, and the edge of the housing is inserted into the first limiting groove.

32. The cylindrical battery according to any one of claims 1 to 25, wherein The cylindrical battery also includes a housing, in which the battery cell is assembled. A second limiting groove is provided on the edge of the housing, and the edge of the conductive connector is inserted into the second limiting groove.

33. The cylindrical battery of any one of claims 2 to 25, wherein, The cylindrical battery also includes a housing, in which the battery cell is assembled. The distance between the protrusion and the inner surface of the housing is R3, and the diameter of the housing is R4, where 0.4R4≥R3≥0.15R4.

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