Welding structure of cap and collector plate and cylindrical secondary battery
By optimizing the welding structure between the cap and the current collector, the problems of increased battery internal resistance and poor welding caused by unreasonable solder mark size were solved, ensuring stable battery performance and reliable welding quality, and realizing efficient and low-cost battery manufacturing.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- JIANGSU RELIANCE ENERGY TECHNOLOGY CO LTD
- Filing Date
- 2025-05-19
- Publication Date
- 2026-04-28
AI Technical Summary
In the existing technology, the size ratio of the solder marks at the connection between the lower end plate of the cap and the tail body is unreasonable, which leads to increased internal resistance of the battery, weakened overcurrent capacity of the solder wire, and increased risk of poor welding, affecting battery performance and production efficiency.
By rationally designing the area ratio, length, height, distance, and shape of the soldering area, ensure that the soldering area is between 4.5% and 8.5%, the soldering length is between 3.5mm and 4.5mm, the height is between 1mm and 2mm, the distance is within a specific range, and adopt a wavy design for the soldering with an included angle between 25° and 65°.
This achieves stable battery performance and reliable welding quality, avoiding increased battery internal resistance, increased risk of poor welding lines, and decreased production efficiency caused by solder marks that are too small or too large. It achieves a balanced optimization of battery production in terms of performance, quality, and efficiency.
Smart Images
Figure CN224177427U_ABST
Abstract
Description
Technical Field
[0001] This utility model belongs to the field of battery technology, and in particular relates to a welding structure of a cap and a current collector and a cylindrical secondary battery. Background Technology
[0002] As a crucial component of cylindrical batteries, the current collector is responsible for collecting the current generated by the positive electrode active material during charging and discharging. It efficiently conducts this current to the cap, and then transmits it to the external circuitry through the connection points on the cap, thus enabling the battery's energy output and input. Furthermore, the current collector provides stable support for the positive electrode active material, effectively reducing the battery's internal resistance, promoting ion transport, and effectively ensuring battery performance and lifespan.
[0003] In cylindrical batteries, the current collector is typically located at the positive electrode, close to the inside of the cap. The current collector is usually welded to the lower end plate of the cap. For example, patent CN216928872U discloses a current collector designed as a stacked structure of a first body and a second body, which are connected by a connector to form a hollow area with an injection hole. The first body is used for welding to the positive electrode tab, and the second body is used for welding to the cap or outer casing. The injection hole facilitates the injection of electrolyte into the bare cell, while the hollow area provides convenience for sealing.
[0004] The size ratio of the solder mark at the connection between the lower end plate of the cap and the tail body not only affects the connection between the current collector and the cap, but also affects battery performance. If the solder mark is too small, it will lead to increased battery internal resistance and weakened current carrying capacity of the solder wire, which will in turn cause abnormal temperature rise of the solder wire and battery; if the solder mark is too large, it will increase the risk of poor welding, resulting in increased manufacturing costs and reduced production efficiency.
[0005] Therefore, it is of great significance to rationally design the size and / or proportion of the solder mark at the connection between the lower end plate of the cap and the tail body to ensure the connection effect between the current collector and the cap and the battery performance. Utility Model Content
[0006] To address the shortcomings of related technologies, this utility model provides a welding structure for the cap and the collector plate, as well as a cylindrical secondary battery. By rationally designing the welding ratio at the connection between the lower end plate and the tail body, a good connection effect is achieved between the collector plate and the cap.
[0007] This utility model provides a welding structure for a cap and a collector plate, used to connect the lower end plate of the cap and the tail of the collector plate; the middle part of the lower end plate is provided with a receiving groove, which is used to receive the welding wire of the lower end plate and the explosion-proof sheet; the outer edge of the lower end plate is provided with air holes, and the area of the remaining area of the lower end plate excluding the receiving groove and air holes is S0.
[0008] The weld marks between the tail section and the lower end plate form a weld mark area, which covers the entire weld mark; the area of the weld mark area is S2.
[0009] The ratio of S2 to S0 is greater than or equal to 4.5% and less than or equal to 8.5%.
[0010] In this technical solution, by setting the ratio of the area S0 of the remaining area of the lower end plate after removing the receiving groove and the air hole to the area S2 of the soldering area to 4.5% to 8.5%, the battery performance is reduced due to the increase in internal resistance, weakened current carrying capacity of the soldering wire, and increased temperature caused by the soldering area being too small. At the same time, the problem of increased risk of soldering defects, increased welding defect rate, increased manufacturing cost, decreased production efficiency and poor resistance improvement caused by the soldering area being too large is avoided. Thus, the battery performance is ensured to be stable and the welding quality is reliable, achieving a balanced optimization of battery production in terms of performance, quality and efficiency.
[0011] In some embodiments, the length L11 of the solder mark is greater than or equal to 3.5 mm and less than or equal to 4.5 mm.
[0012] In this technical solution, by ensuring that the length L11 of the solder mark is greater than or equal to 3.5 mm and less than or equal to 4.5 mm, there is a sufficient effective welding area between the lower end plate and the tail body, which enables the solder wire to have good current carrying capacity and avoids abnormal temperature rise of the solder wire due to weakened current carrying capacity, thereby ensuring stable battery performance.
[0013] In some embodiments, the height of the solder mark W23 is greater than or equal to 1 mm and less than or equal to 2 mm.
[0014] In this technical solution, by keeping the solder mark height W23 between 1mm and 2mm, the solder mark area is ensured to be appropriate. This prevents the battery internal resistance from increasing and the overcurrent capacity from weakening due to excessive height, while also preventing the risk of poor soldering and the soldering failure rate from increasing due to excessive height, thus ensuring soldering quality.
[0015] In some embodiments, the length direction of the solder mark is set along the width direction of the tail body, and the minimum distance from both ends of the solder mark in the length direction to the corresponding end of the tail body is greater than or equal to 0.6 mm and less than or equal to 1.4 mm.
[0016] In this technical solution, by ensuring that the minimum distance between the two ends of the solder mark in the length direction and the corresponding end of the tail body is between 0.6mm and 1.4mm, the solder mark is located in the middle part of the tail body, avoiding the offset of the solder line due to the distance being too small or too large, ensuring the effective welding area, and thus ensuring battery performance.
[0017] In some embodiments, the width L1 of the tail body is greater than or equal to 5 mm and less than or equal to 7 mm.
[0018] In this technical solution, by ensuring that the width L1 of the tail body is greater than or equal to 5mm and less than or equal to 7mm, a suitable welding area is provided between the tail body and the lower end plate, ensuring that the weld area meets the requirements. This helps to guarantee welding quality and battery performance, avoiding the increased cost, process complexity, and space layout problems caused by an excessively long tail body, and preventing welding defects and battery performance degradation caused by an excessively short tail body. This achieves a balanced optimization of battery production in terms of performance, quality, and efficiency.
[0019] In some embodiments, the distance W21 from the top of the solder mark to the center of the lower end plate is greater than or equal to 1.6 mm and less than or equal to 2.2 mm.
[0020] In this technical solution, by keeping the distance W21 between the top of the solder mark and the center of the lower end plate between 1.6mm and 2.2mm, the solder line is placed in the optimal working area, ensuring sufficient effective welding area and excellent current flow performance.
[0021] In some embodiments, the distance W22 from the bottom of the solder mark to the edge of the lower end plate is greater than or equal to 2.59 mm and less than or equal to 3.19 mm.
[0022] In this technical solution, by keeping the distance W22 between the bottom of the solder mark and the edge of the lower end plate between 2.59mm and 3.19mm, the solder line is located in the optimal working area, ensuring sufficient effective welding area and excellent current flow performance.
[0023] In some embodiments, the area S2 of the solder mark region is greater than or equal to 5 mm. 2 And less than or equal to 7mm 2 .
[0024] In this technical solution, the area S2 of the solder area is greater than or equal to 5mm. 2 And less than or equal to 7mm 2 This ensures that the area of the soldering area is within a suitable range, avoiding the reduction in battery performance caused by an excessively small soldering area, which leads to increased internal resistance, weakened current-carrying capacity of the soldering wire, and increased temperature. Conversely, it avoids the problems caused by an excessively large soldering area, such as increased risk of soldering defects, higher welding failure rate, increased manufacturing costs, decreased production efficiency, and poor resistance improvement. This ensures stable battery performance and reliable welding quality, achieving a balanced optimization of battery production in terms of performance, quality, and efficiency.
[0025] In some embodiments, the solder mark is wavy. At the crest of the wavy curve, the angle formed by the curve turning is denoted as angle A, which is greater than or equal to 25° and less than or equal to 65°. At the trough of the wavy curve, the angle formed by the curve turning is denoted as angle B, which is greater than or equal to 25° and less than or equal to 65°.
[0026] In this technical solution, the solder mark is made to be wavy, with the curve turning angle A at the crest and the curve turning angle B at the trough both between 25° and 65°. This avoids the solder wire energy and heat concentration caused by too small an angle, which could lead to soldering defects such as blasting and changes in solder wire color. It also avoids the total length of the solder wire increasing due to too large an angle, which could easily lead to soldering onto the outside of the current collector, reducing the effective welding area, weakening the current carrying capacity, and increasing the solder wire temperature, thus further ensuring the welding quality.
[0027] In addition, this utility model also provides a cylindrical secondary battery, including the aforementioned welded structure of the cap and the current collector.
[0028] Based on the above technical solution, the welding structure of the cap and the current collector in this utility model embodiment achieves a balanced optimization of battery production in terms of performance, quality and efficiency by reasonably controlling the relevant parameters of the welding stamp, avoiding situations such as increased welding time and reduced production efficiency due to excessive welding stamp length, and increased manufacturing costs due to excessive welding stamp area. Attached Figure Description
[0029] The accompanying drawings, which are included to provide a further understanding of the present invention and form part of this application, illustrate exemplary embodiments of the present invention and, together with the description thereof, serve to explain the present invention and do not constitute an undue limitation thereof. In the drawings:
[0030] Figure 1 This is a schematic diagram of one embodiment of the welding structure of the cap and the collector plate of this utility model;
[0031] Figure 2 This is a schematic diagram of the connection between the lower end plate and the tail body in one embodiment of the welding structure of the cap and the collector plate of this utility model.
[0032] Figure 3 for Figure 2 Enlarged view of a portion of point A in the middle;
[0033] Figure 4 This is a partial dimension marking diagram of the connection between the lower end plate and the tail body in one embodiment of the welding structure of the cap and the collector plate of this utility model;
[0034] Figure 5 This is a dimension marking diagram of the tail body and the weld mark in one embodiment of the welding structure of the cap and the collector plate of this utility model.
[0035] In the picture:
[0036] 1. Cap; 2. Collector plate; 3. Core; 4. Solder stamp;
[0037] 11. Lower end plate;
[0038] 111. Vents; 112. Receiving grooves;
[0039] 21. Tail body;
[0040] 401. Solder stamp area. Detailed Implementation
[0041] The technical solutions in the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. 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.
[0042] In the description of this utility model, it should be understood that the terms "center", "lateral", "longitudinal", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", and "outer" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this utility model.
[0043] The terms "first," "second," and "third" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined as "first," "second," or "third" may explicitly or implicitly include one or more of that feature.
[0044] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "joining" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.
[0045] like Figure 1 As shown, the core 3 is the core component of the battery, responsible for storing and releasing electrical energy, generating current through internal chemical reactions. The current collector 2 is typically connected to the electrodes of the core 3, collecting the current generated by the core 3 and transmitting it to an external circuit. The cap 1, located on top of the battery and connected to the current collector 2, leads the current from inside the battery to the external circuit, providing power to electrical devices. The current collector 2 typically includes a tail 21 and a disc body; the disc body is connected to the core 3, and the tail 21 is connected to the cap 1.
[0046] The cap 1 includes an upper cover plate, an explosion-proof sheet, an inner rubber ring, a lower end plate 11, and an outer insulating ring. The upper cover plate, explosion-proof sheet, inner rubber ring, and lower end plate 11 are arranged sequentially in a vertical direction, and the outer insulating ring is sleeved on the outer periphery of the explosion-proof sheet and the upper cover plate. The specific structure of the cap 1 is common knowledge in the art and will not be described in detail here.
[0047] As attached Figures 2-5 As shown in an illustrative embodiment of the welding structure of the cap and the collector plate of this utility model, the welding structure of the cap and the collector plate is achieved by welding the lower end plate 11 and the tail body 21 to realize the connection between the cap 1 and the collector plate 2.
[0048] The lower end plate 11 has a receiving groove 112 in the middle part, which is used to receive the welding wire of welding the lower end plate 11 to the explosion-proof sheet; the lower end plate 11 has a vent 111 on the outer edge, which allows the gas in the battery to pass through the vent 111 and contact the explosion-proof sheet to prevent the gas from accumulating and causing an explosion; the area of the lower end plate 11 excluding the receiving groove 112 and the vent 111 is S0; the weld 4 between the tail body 21 and the lower end plate 11 forms a weld area 401, which covers the entire weld 4; the area of the weld area 401 is S2; wherein, the ratio of S2 to S0 is greater than or equal to 4.5% and less than or equal to 8.5%.
[0049] For ease of description, the area remaining in the lower end plate 11 after removing the receiving groove 112 and the air hole 111 is called the first region, and the area of the first region is S0.
[0050] If the ratio of the area S2 of the solder area 401 to the area S0 of the first area is too small, the area of the solder area 401 will be small, the internal resistance of the battery will increase, and the current carrying capacity of the solder wire will be weakened, resulting in an increase in the temperature of the solder wire, which in turn will cause the battery temperature to rise and reduce the battery performance.
[0051] If the ratio of the area S2 of the solder area 401 to the area S0 of the first area is too large, the area of the solder area 401 will be large, which will not only increase the risk of poor soldering and increase the failure rate of welding, but also increase the manufacturing cost of the battery, reduce efficiency, and have no better effect on improving the resistance of the battery.
[0052] The area S2 of the solder mark region 401 is 5 mm. 2 ~7mm 2 If the area of the solder area 401 is small, the internal resistance of the battery will increase and the current carrying capacity of the solder wire will be weakened, resulting in an increase in the temperature of the solder wire, which in turn will cause the battery temperature to rise and reduce battery performance. If the area of the solder area 401 is large, it will not only increase the risk of solder wire defects and increase the failure rate of welding, but also increase the manufacturing cost of the battery, reduce efficiency, and have no better effect on improving the resistance of the battery.
[0053] like Figure 3 As shown, the solder area 401 is the area that covers all solder marks 4. Sometimes the solder mark 4 is not a regular shape. Therefore, the shape of the solder area 401 is also not a regular shape. In this embodiment, the solder area 401 is defined by the length and height of the solder mark 4. That is, the length of the solder mark 4 is the length of the solder area 401, and the height of the solder mark 4 is the height of the solder area 401. The solder area 401 is rectangular. The dotted line in the figure represents the boundary line of the solder area 401.
[0054] In this embodiment, the area S0 of the first region is 89.25 mm². 2 The area S2 of the solder mark region 401 is 6mm. 2 The ratio of S2 to S0 is 6.7% to ensure that the ratio of the area S2 of the solder area 401 to the area S0 of the first region is within an appropriate range. This avoids the battery performance being reduced due to an excessively small area of the solder area 401, which would lead to an increase in battery internal resistance, a weakening of the wire bonding current capacity, and an increase in temperature. At the same time, it avoids the problems caused by an excessively large solder area 401, such as an increased risk of poor wire bonding, an increased welding defect rate, increased manufacturing costs, decreased production efficiency, and poor resistance improvement. This ensures stable battery performance and reliable welding quality, achieving a balanced optimization of battery production in terms of performance, quality, and efficiency.
[0055] It should be noted that a weld line refers to a continuous or discontinuous linear area of weld metal deposition formed along the weld joint during the welding process. A weld mark (4), on the other hand, is the overall trace left on the surface of the workpiece after welding, which may consist of one or more weld lines and the surrounding heat-affected zone. The relationship between weld marks (4) and weld lines is common knowledge in the art and will not be elaborated upon here.
[0056] like Figure 4 As shown, the distance W21 between the top of solder mark 4 and the center of the lower end plate 11 is greater than or equal to 1.6 mm and less than or equal to 2.2 mm.
[0057] If the distance between the top of the solder mark 4 and the center of the lower end plate 11 is too small, the solder line will be close to the upper end of the tail body 21. Due to the reasonable process offset tolerance during the manufacturing process, the solder line being close to the upper end of the tail body 21 can easily cause the solder line to be soldered out of the tail body 21, resulting in a reduction of the effective welding area between the lower end plate 11 and the tail body 21, a weakening of the current carrying capacity of the solder line, and an increase in temperature at the solder line, which will affect the performance of the battery.
[0058] If the distance between the top of the solder mark 4 and the center of the lower end plate 11 is too large, the solder line will be close to the lower end of the tail body 21. The solder line will move down and easily exceed the surface of the lower end plate 11, causing the solder line to be soldered out of the surface area of the lower end plate 11. This will reduce the effective welding area between the lower end plate 11 and the tail body 21, weaken the current carrying capacity of the solder line, and increase the temperature at the solder line, affecting the performance of the battery. The tail body 21 needs to be completely attached to the surface of the lower end plate 11 for welding.
[0059] In this embodiment, the distance W21 between the top of the solder mark 4 and the center of the lower end plate 11 is 1.8mm, so that the solder line is located in the optimal working area, neither too close to the tail end of the collector plate 2 nor exceeding the effective surface of the lower end plate 11, so as to ensure sufficient effective welding area and excellent current flow performance.
[0060] like Figure 4 As shown, the distance W22 from the bottom of solder mark 4 to the edge of the lower end plate 11 is greater than or equal to 2.59 mm and less than or equal to 3.19 mm.
[0061] If the distance between the bottom of the solder mark 4 and the edge of the lower end plate 11 is too small, the solder line will be close to the lower end of the tail body 21. The solder line will move down and easily exceed the surface of the lower end plate 11, causing the solder line to be soldered out of the surface area of the lower end plate 11. This will reduce the effective welding area between the lower end plate 11 and the tail body 21, weaken the current carrying capacity of the solder line, and increase the temperature at the solder line, affecting the performance of the battery. The tail body 21 needs to be completely attached to the surface of the lower end plate 11 for welding.
[0062] If the distance between the bottom of the solder mark 4 and the edge of the lower end plate 11 is too large, the solder line will be close to the upper end of the tail body 21. Due to the reasonable process offset tolerance during the manufacturing process, the solder line being close to the upper end of the tail body 21 will easily cause the solder line to be soldered out of the tail body 21, resulting in a reduction of the effective welding area between the lower end plate 11 and the tail body 21, a weakening of the current carrying capacity of the solder line, an increase in temperature at the solder line, and an impact on the battery performance.
[0063] In this embodiment, the distance W22 between the bottom of the solder mark 4 and the edge of the lower end plate 11 is 2.99mm, so that the solder line is located in the optimal working area, neither too close to the tail end of the collector plate 2 nor exceeding the effective surface of the lower end plate 11, so as to ensure sufficient effective welding area and excellent current flow performance.
[0064] like Figure 5As shown, the height W23 of solder mark 4 is greater than or equal to 1 mm and less than or equal to 2 mm. If the height W23 of solder mark 4 is too small, the area of solder mark region 401 will be small, the internal resistance of the battery will increase, and the current carrying capacity of the solder wire will be weakened, resulting in an increase in the temperature of the solder wire, which in turn will cause the battery temperature to rise and reduce battery performance. If the height W23 of solder mark 4 is too large, the area of solder mark region 401 will be large, which will not only increase the risk of solder wire defects and increase the welding defect rate, but also increase the manufacturing cost of the battery, reduce efficiency, and have no better effect on improving the battery resistance.
[0065] In this implementation, the height W23 of the solder mark 4 is 1.5mm, which makes the area of the solder mark area 401 suitable, ensuring stable battery performance and reliable welding quality, and achieving a balanced optimization of battery production in terms of performance, quality and efficiency.
[0066] like Figure 5 As shown, the length L11 of the solder mark 4 is greater than or equal to 3.5 mm and less than or equal to 4.5 mm. If the length of the solder mark 4 is too short, the welding line will be shortened accordingly, resulting in a reduction in the effective welding area between the lower end plate 11 and the tail body 21. This not only weakens the current carrying capacity of the welding line, but also causes a sharp increase in temperature at the welding line, ultimately negatively impacting battery performance. Conversely, if the length of the solder mark 4 is too large, the welding line will become longer. Increasing the length of the solder mark 4 cannot further improve the battery's internal resistance, but it will increase the welding time required between the lower end plate 11 and the tail body 21. This will not only reduce production efficiency but also increase the risk of welding defects, leading to a rise in the welding defect rate, which in turn affects product quality and production efficiency.
[0067] In this embodiment, the length L11 of the solder mark 4 is 4mm, so that there is a sufficient effective welding area between the lower end plate 11 and the tail body 21, so that the solder wire has good current carrying capacity and avoids abnormal temperature rise of the solder wire due to weakened current carrying capacity, thereby ensuring stable battery performance.
[0068] like Figure 5 As shown, the length direction of the solder mark 4 is set along the width direction of the tail body 21, and the minimum distance from both ends of the solder mark 4 in the width direction to the corresponding ends of the tail body 21 is greater than or equal to 0.6 mm and less than or equal to 1.4 mm.
[0069] When the width direction of the tail body 21 is set along the left and right direction of the tail body 21, the minimum distance L10 between the solder mark 4 and the left side of the tail body 21 is greater than or equal to 0.6 mm and less than or equal to 1.4 mm, and the minimum distance L12 between the solder mark 4 and the right side of the tail body 21 is greater than or equal to 0.6 mm and less than or equal to 1.4 mm.
[0070] If the minimum distance between the solder mark 4 and the left side of the tail body 21 is too small, the solder line will be biased towards the left side of the tail body 21; if the minimum distance between the solder mark 4 and the right side of the tail body 21 is too small, the solder line will be biased towards the right side of the tail body 21; if the minimum distance between the solder mark 4 and the left side of the tail body 21 is too large, the solder line will be biased towards the right side of the tail body 21; if the minimum distance between the solder mark 4 and the right side of the tail body 21 is too large, the solder line will be biased towards the left side of the tail body 21.
[0071] Because there is a certain reasonable process offset tolerance during the manufacturing process, the bonding wire is very close to the edge, which can easily cause the bonding wire to be soldered out onto the side of the positive current collector 2. This results in a smaller effective welding area, a weakened current carrying capacity of the bonding wire, and an increased temperature at the bonding wire, which affects the performance of the battery.
[0072] In this embodiment, the minimum distance L10 between the solder mark 4 and the left side of the tail body 21 is 1mm, and the minimum distance L12 between the solder mark 4 and the right side is 1mm, so that the solder mark 4 is located in the middle part of the tail body 21, and the distances from both sides of the solder mark 4 in the length direction to the left and right sides of the tail body 21 are moderate.
[0073] like Figure 5 As shown, the width L1 of the tail body 21 is greater than or equal to 5 mm and less than or equal to 7 mm. If the width L1 of the tail body 21 is too large, manufacturing the tail body 21 will consume more metal materials, increasing manufacturing costs, but will not significantly improve the battery's internal resistance or overcurrent capacity. In addition, the solder mark 4 needs to cover a larger area, which may lead to uneven distribution of welding energy, making it prone to defects such as cold solder joints and explosions, increasing the defect rate. The longer solder mark 4 requires a longer welding time, reducing production efficiency. If the width L1 of the tail body 21 is too small, it may lead to insufficient connection area between the tail body 21 and the lower end plate 11. The solder mark 4 may easily shift or even exceed the boundary of the tail body 21, resulting in a smaller effective welding area, affecting structural stability, and making it prone to cracking under vibration or impact, leading to increased internal resistance, weakened overcurrent capacity, local temperature rise, and reduced battery performance and lifespan.
[0074] In this embodiment, the width L1 of the tail body 21 is 6mm, so that there is a suitable welding area between the tail body 21 and the lower end plate 11, ensuring that the area of the solder mark 4 meets the requirements. This is beneficial to ensuring welding quality and battery performance. It can avoid the increased cost, process complexity and space layout problems caused by the tail body 21 being too long, and also prevent welding defects and battery performance degradation caused by the tail body 21 being too short. This achieves a balanced optimization of battery production in terms of performance, quality and efficiency.
[0075] like Figure 5As shown, solder mark 4 is wavy, and the wavy curve is composed of continuous alternating peaks and troughs. At the peak, the angle formed by the curve turning is denoted as angle A, which is greater than or equal to 25° and less than or equal to 65°; at the trough, the angle formed by the curve turning is denoted as angle B, which is greater than or equal to 25° and less than or equal to 65°.
[0076] If the included angle A is too small, the welding wires tend to cluster together, concentrating all the energy and heat, which can lead to breakage, color changes, and an increased failure rate. If the included angle A is too large, the total length of the welding wires increases. Due to manufacturing process deviations, the increased lateral distance between the beginning and end of the welding wires makes them more likely to approach the sides of the positive current collector 2. Because of these manufacturing process deviations, the welding wires may extend beyond the outside of the current collector 2, reducing the effective welding area, weakening the current carrying capacity, and increasing the temperature at the welding point, thus affecting battery performance.
[0077] Similarly, if the included angle B is too small, the welding wires tend to cluster together, and the energy and heat of the welding wires become completely concentrated, leading to potential explosions, color changes, and an increased welding defect rate. If the included angle B is too large, the total length of the welding wires increases. Due to process deviations in the welding wires themselves, the increased straight-line distance between the beginning and end of the welding wires in the lateral direction makes them more likely to approach the sides of the positive current collector 2. Due to reasonable process deviations, the welding wires are prone to weld outside the current collector 2, resulting in a reduction in the effective welding area, weakened welding current carrying capacity, and increased temperature at the welding wires, thus affecting battery performance.
[0078] In this embodiment, the included angle A is 41° and the included angle B is also 41°.
[0079] Based on the above-mentioned welding structure of the cap and the current collector, this utility model also provides a cylindrical secondary battery, which includes the above-mentioned welding structure of the cap and the current collector.
[0080] Through the description of several embodiments of the welding structure of the cap and the collector plate of this utility model, it can be seen that the welding structure embodiments of the cap and the collector plate of this utility model have at least one or more of the following advantages:
[0081] 1. Reasonably set the ratio of the area S2 of the soldering area 401 to the area S0 of the first area, so that the ratio of the area S2 of the soldering area 401 to the area S0 of the first area is within the range of 4.5% to 8.5%. This avoids the battery performance being reduced due to the soldering area 401 being too small, which would lead to an increase in battery internal resistance, a weakening of the overcurrent capacity of the soldering wire, and an increase in temperature. It also avoids the battery performance being reduced due to the soldering area 401 being too large, which would increase the risk of soldering defects, the welding defect rate, and manufacturing costs, and would not have a better effect on improving battery resistance. This ensures stable battery performance.
[0082] 2. By keeping the length L11 of the solder mark 4 between 3.5mm and 4.5mm, there is a sufficient effective welding area between the lower end plate 11 and the tail body 21, ensuring that the solder wire has good current carrying capacity, avoiding abnormal temperature rise of the solder wire due to weakened current carrying capacity, and ensuring welding quality.
[0083] 3. By keeping the height W23 of the solder mark 4 between 1mm and 2mm, the area of the solder mark area 401 is ensured to be appropriate. The height will not be too small, which will cause the battery internal resistance to increase and the overcurrent capacity to weaken. Nor will the height be too large, which will increase the risk of poor soldering and the welding defect rate, thus ensuring the welding quality.
[0084] 4. By keeping the minimum distance between the solder mark 4 and the left and right sides of the tail body 21 between 0.6mm and 1.4mm, the solder mark 4 is located in the middle part of the tail body 21, avoiding the offset of the solder line due to the distance being too small or too large, ensuring the effective welding area, and thus ensuring the battery performance.
[0085] 5. By making the distance W21 between the top of the solder mark 4 and the center of the lower end plate 11 between 1.6mm and 2.2mm, and the distance W22 between the bottom of the solder mark 4 and the edge of the lower end plate 11 between 2.59mm and 3.19mm, the solder line is placed in the optimal working area, ensuring sufficient effective soldering area and excellent current flow performance.
[0086] 6. By making the solder mark 4 wavy, with the curve turning angle A at the crest and the curve turning angle B at the trough both between 25° and 65°, we avoid the solder wire energy and heat concentration caused by too small an angle, which may result in soldering defects such as blasting and changes in solder wire color. We also avoid the total length of the solder wire increasing due to too large an angle, which may cause the solder wire to easily extend to the outside of the current collector 2, reducing the effective welding area, weakening the current carrying capacity, and increasing the solder wire temperature, thus further ensuring the welding quality.
[0087] Finally, it should be noted that the various embodiments in this specification are described in a progressive manner, with each embodiment focusing on the differences from other embodiments. The same or similar parts between the various embodiments can be referred to each other.
[0088] The above embodiments are only used to illustrate the technical solution of this utility model and not to limit it; although the utility model has been described in detail with reference to preferred embodiments, those skilled in the art should understand that modifications can still be made to the specific implementation of this utility model or equivalent substitutions can be made to some technical features without departing from the spirit of the technical solution of this utility model, and all such modifications and substitutions should be covered within the scope of the technical solution claimed by this utility model.
Claims
1. A welded structure for a cap and a collector plate, used to connect the lower end plate (11) of the cap and the tail body (21) of the collector plate; characterized in that, The lower end plate (11) has a receiving groove (112) in the middle part, which is used to receive the welding wire for welding the lower end plate (11) and the explosion-proof sheet; the lower end plate (11) has a vent (111) on the outer edge, and the area of the remaining area of the lower end plate (11) excluding the receiving groove (112) and the vent (111) is S0; The solder joint (4) between the tail body (21) and the lower end plate (11) forms a solder joint area (401), which covers the entire solder joint (4); the area of the solder joint area (401) is S2. The ratio of S2 to S0 is greater than or equal to 4.5% and less than or equal to 8.5%.
2. The welding structure of the cap and the collector plate according to claim 1, characterized in that, The length L11 of the solder mark (4) is greater than or equal to 3.5 mm and less than or equal to 4.5 mm.
3. The welding structure of the cap and the collector plate according to claim 1, characterized in that, The height W23 of the solder mark (4) is greater than or equal to 1 mm and less than or equal to 2 mm.
4. The welding structure of the cap and the collector plate according to claim 1, characterized in that, The length direction of the weld mark (4) is set along the width direction of the tail body (21), and the minimum distance L10 or L12 from both ends of the weld mark (4) to the corresponding ends of the tail body (21) is greater than or equal to 0.6 mm and less than or equal to 1.4 mm.
5. The welding structure of the cap and the collector plate according to claim 1, characterized in that, The width L1 of the tail body (21) is greater than or equal to 5 mm and less than or equal to 7 mm.
6. The welding structure of the cap and the collector plate according to claim 1, characterized in that, The distance W21 between the top of the solder mark (4) and the center of the lower end plate (11) is greater than or equal to 1.6 mm and less than or equal to 2.2 mm.
7. The welding structure of the cap and the collector plate according to claim 1, characterized in that, The distance W22 from the bottom of the solder mark (4) to the edge of the lower end plate (11) is greater than or equal to 2.59 mm and less than or equal to 3.19 mm.
8. The welding structure of the cap and the collector plate according to claim 7, characterized in that, The area S2 of the solder area (401) is greater than or equal to 5 mm. 2 And less than or equal to 7mm 2 .
9. The welding structure of the cap and the collector plate according to claim 1, characterized in that, The solder mark (4) is wavy. At the peak of the wavy curve, the angle formed by the curve turning is called angle A, which is greater than or equal to 25° and less than or equal to 65°. At the trough of the wavy curve, the angle formed by the curve turning is called angle B, which is greater than or equal to 25° and less than or equal to 65°.
10. A cylindrical secondary battery, characterized in that, The welded structure of the cap and the manifold as described in any one of claims 1 to 9.