A cylindrical secondary battery

Abstract

The utility model provides a kind of cylindrical secondary battery, including cover plate, negative pole current collector, shell and roll core, the negative pole current collector includes disc body part, tail end part and connecting part, the both sides of connecting part are fixedly connected with disc body part and tail end part, and connecting part is perpendicular with disc body part;Disc body part is fixedly connected with the pole lug end surface of roll core, and tail end part is fixedly connected with cover plate;The perpendicular maximum distance between tail end part and shell top end face is L3, the perpendicular maximum distance between connecting part and shell top end face is L30, satisfy: L30 / L3=59.7%~70.7%;The cylindrical secondary battery, by reasonable control connecting part and shell top end face between the perpendicular maximum distance and the perpendicular maximum distance between tail end part and shell top end face, both can guarantee that cover plate and negative pole current collector welding do not interfere with shell mouth, also can avoid negative pole current collector bending into shell and shell wall interference or metal chip produced by scraping, improve battery assembly yield and performance safety.

Description

Technical Field

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

[0002] A battery is a cup, tank, or other container or composite container that contains an electrolyte solution and metal electrodes to generate an electric current. It is a device that converts chemical energy into electrical energy. A battery generally includes a casing and a core located inside the casing. During battery manufacturing, electrolyte needs to be injected into the casing so that the electrolyte fills the core. For batteries with injection holes, the injection holes need to be sealed after the electrolyte is injected.

[0003] The patent application CN222463346U discloses a cylindrical lithium-ion battery cap and a cylindrical lithium-ion battery, including a negative electrode current collector body. The negative electrode current collector body has a negative electrode current collector groove on the surface opposite to the battery cell. One end of the negative electrode current collector groove is connected to a bendable negative electrode current collector connecting part. The negative electrode current collector connecting part is used to connect the cylindrical battery negative electrode cap to the cylindrical battery negative electrode current collector.

[0004] Currently, in battery manufacturing, there is an unreasonable distance between the part of the negative electrode current collector that is welded to the cover plate and the part that is welded to the end face of the tab. When the distance is too small, the cover plate can only be welded to the negative electrode current collector on the outside of the shell opening, which is easy to interfere with the shell opening and affect assembly. When the distance is too large, the bending space of the negative electrode current collector is limited, and it is easy to interfere with and scratch the shell wall during bending. This not only reduces the assembly yield, but the metal shavings generated by the scratching can also cause short circuits in the battery, resulting in poor K value and affecting battery performance and safety. Utility Model Content

[0005] In view of this, the present invention proposes a cylindrical secondary battery. By reasonably controlling the ratio range of the maximum vertical distance between the connecting part and the top surface of the casing and the maximum vertical distance between the tail end and the top surface of the casing, it can ensure that the cover plate does not interfere with the casing opening when welding the negative electrode current collector, and can also avoid interference or scratching of the casing wall when the negative electrode current collector is bent into the casing, thereby improving the battery assembly yield and performance safety.

[0006] The technical solution of this utility model is achieved as follows: This utility model provides a cylindrical secondary battery, including a cover plate, a negative electrode current collector, a casing, and a winding core.

[0007] The negative electrode current collector includes a disk body, a tail end, and a connecting part. The two sides of the connecting part are fixedly connected to the disk body and the tail end, respectively, and the connecting part is perpendicular to the disk body.

[0008] The disc body is fixedly connected to the tab end face of the winding core, and the tail end is fixedly connected to the cover plate.

[0009] The maximum vertical distance between the tail end and the top surface of the shell is L3, and the maximum vertical distance between the connecting part and the top surface of the shell is L30, satisfying: L30 / L3=59.7%~70.7%.

[0010] Based on the above technical solutions, preferably, the shortest distance between the connection point of the connecting part and the protruding edge of the cover plate and the top surface of the shell is L31, which satisfies: L31 / L3 = 24.6%~32.0%.

[0011] Based on the above technical solutions, preferably, the maximum vertical distance L3 between the tail end and the top surface of the shell is 51.6mm to 57.6mm.

[0012] Based on the above technical solutions, preferably, the height of the shell is H30, and satisfies: L3 / H30 = 43.8% to 47.6%.

[0013] Based on the above technical solutions, preferably, the diameter of the shell is W30, the maximum straight-line distance from the outer edge of the shell to the connecting part is W40, and satisfies: W40 / W30 = 77.8%~90.9%.

[0014] Based on the above technical solutions, preferably, the diameter W30 of the shell is 43mm to 49mm.

[0015] Based on the above technical solutions, preferably, the width of the connecting part is W, and satisfies: W = 26mm ~ 30mm.

[0016] Based on the above technical solutions, preferably, the maximum width of the tail end is D30, and satisfies: D30 = 35.2mm to 39.2mm.

[0017] Based on the above technical solutions, preferably, the area of ​​the tab end face of the core is S40, and the area of ​​the disc body covering the core is S41, and satisfies: S41 / S40 = 71.4%~81.4%.

[0018] Based on the above technical solutions, preferably, the height H30 of the shell is 114.6mm to 124.6mm.

[0019] The cylindrical secondary battery of this invention has the following advantages over the prior art:

[0020] (1) By reasonably controlling the ratio range of the maximum vertical distance between the connecting part and the top surface of the shell and the maximum vertical distance between the tail end and the top surface of the shell, it can be ensured that the cover plate does not interfere with the shell opening when welding the negative electrode current collector, and avoid interference or scraping of the shell wall when the negative electrode current collector is bent into the shell, thereby improving the battery assembly yield and performance safety.

[0021] (2) By reasonably controlling the ratio of the maximum straight distance from the outer edge of the shell to the connection part to the diameter of the shell, it can ensure that the disc part and the core have sufficient effective welding area, reduce the temperature rise at the welding line and the internal resistance of the battery, and avoid interference or scraping between the negative electrode current collector and the shell wall to generate metal chips, thereby effectively improving battery performance and assembly yield.

[0022] (3) By reasonably controlling the width range of the connection part, it can ensure that the connection part has sufficient overcurrent capacity, avoid battery failure due to heat generation during high-rate charging and discharging, and prevent interference or scratching with the shell wall after bending, thus effectively improving battery performance and assembly yield. Attached Figure Description

[0023] To more clearly illustrate the technical solutions in the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0024] Figure 1 This is a perspective view of the cylindrical secondary battery of this utility model;

[0025] Figure 2 This is a front view of the cylindrical secondary battery of this utility model;

[0026] Figure 3 This is a schematic diagram showing the markings on the tail end and connecting part of the cylindrical secondary battery of this utility model;

[0027] Figure 4 This is a schematic diagram showing the connection part and cap markings of the cylindrical secondary battery of this utility model.

[0028] Figure 5 This is a side cross-sectional view of the cylindrical secondary battery of this utility model;

[0029] Figure 6 This is a top view of the cylindrical secondary battery of this utility model. Detailed Implementation

[0030] The technical solutions of this utility model will be clearly and completely described below with reference to the embodiments of this utility model. Obviously, the described embodiments are only a part of the embodiments of this utility model, and not all of them. Based on the embodiments of this utility model, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the protection scope of this utility model.

[0031] like Figure 1-6 As shown, a cylindrical secondary battery of this utility model includes a cover plate 1, a negative electrode current collector 2, a housing 3, and a winding core 4. The housing 3 is hollow inside, and the winding core 4 is disposed inside the housing 3. The negative electrode current collector 2 includes a disk body portion 21, a tail end portion 22, and a connecting portion 23. The two sides of the connecting portion 23 are fixedly connected to the disk body portion 21 and the tail end portion 22, respectively, and the connecting portion 23 is perpendicular to the disk body portion 21. The disk body portion 21 is fixedly connected to the tab end face of the winding core 4, and the tail end portion 22 is fixedly connected to the cover plate 1. The maximum vertical distance between the tail end portion 22 and the top surface of the housing 3 is L3, and the maximum vertical distance between the connecting portion 23 and the top surface of the housing 3 is L30, satisfying: L30 / L3 = 59.7%~70.7%.

[0032] In addition, the maximum vertical distance L3 between the tail end 22 and the top surface of the shell 3 is 51.6mm to 57.6mm.

[0033] It should be noted that if the maximum vertical distance L30 between the connecting part 23 and the top surface of the housing 3 is too short, the size of the connecting part 23 in the direction perpendicular to the top surface of the housing 3 will be insufficient. When the cover plate 1 is welded to the tail end 22, there needs to be enough space to ensure the smooth progress of the welding operation and the welding quality. When the maximum vertical distance L30 between the connecting part 23 and the top surface of the housing 3 is too short, the cover plate 1 can only be welded to the negative electrode current collector 2 on the outside of the housing opening. In order to meet the welding requirements, the position of the cover plate 1 may exceed the normal assembly range, thereby interfering with the housing opening and making normal assembly impossible.

[0034] When the maximum vertical distance L30 between the connecting part 23 and the top surface of the housing 3 is too large, the length of the connecting part 23 increases. During the assembly process of bending the cover plate 1 into the housing, the negative electrode current collector 2 needs to undergo a certain bending deformation. The excessively long connecting part will occupy a large space, which will restrict the range of motion at the bending point and make it easy to interfere or scratch with the housing wall. Metal shavings generated during the scratching process may enter the battery. Metal shavings inside the battery may cause a short circuit. At the same time, the presence of metal shavings may also cause poor K value of the battery, affecting the performance and safety of the battery.

[0035] In this embodiment, by reasonably controlling the ratio of the maximum vertical distance between the connecting part 23 and the top surface of the housing 3 to the maximum vertical distance between the tail end 22 and the top surface of the housing 3 to be between 59.7% and 70.7%, it can ensure that the cover plate 1 does not interfere with the housing opening when welding the negative electrode current collector 2, and also avoid interference or scratching of the housing wall when the negative electrode current collector 2 is bent into the housing, thereby improving the battery assembly yield and performance safety.

[0036] Specifically, in this embodiment, the maximum vertical distance L3 between the tail end 22 and the top surface of the housing 3 is 54.6 mm; the maximum vertical distance L30 between the connecting part 23 and the top surface of the housing 3 is 35.6 mm.

[0037] In this embodiment, the shortest distance between the connection point of the connecting part 23 and the protruding edge of the cover plate 1 and the top surface of the housing 3 is L31, which satisfies: L31 / L3 = 24.6%~32.0%.

[0038] It should be noted that when the shortest distance L31 between the connection point 23 and the protruding edge of the cover plate 1 and the top surface of the housing 3 is too short, the space for welding operations between the cover plate 1 and the tail end 22 becomes extremely limited. The welding process requires a certain operating area to ensure that the welding equipment can operate accurately, and at the same time, to ensure that the welding point has sufficient strength and quality. Due to insufficient space, the cover plate 1 can only be welded to the negative electrode current collector 2 on the outside of the housing opening. In order to meet the welding requirements, the position of the cover plate 1 will exceed the normal assembly range, thereby interfering with the housing opening and hindering the normal assembly process of the battery.

[0039] If the shortest distance L31 between the connection point of the connecting part 23 and the protruding edge of the cover plate 1 and the top surface of the housing 3 is too large, the length of the connecting part 23 in a specific direction will increase. During the assembly process of bending the cover plate 1 into the housing, the negative electrode current collector 2 needs to be bent and deformed to adapt to the internal structure of the battery. An excessively long connecting part 23 will occupy too much space, which will restrict the range of motion at the bending point. During the bending process, the bending part of the disc part 21 is prone to contact with the housing wall, resulting in interference or scratching. The metal shavings generated by the scratching will remain inside the battery. The presence of metal shavings may cause an internal short circuit in the battery, and will also affect the self-discharge characteristics of the battery, resulting in poor K value and reducing the performance and safety of the battery.

[0040] In this embodiment, the ratio of the shortest distance L31 between the connection point of the connecting part 23 and the protruding edge of the cover plate 1 to the top surface of the housing 3 and the maximum vertical distance L3 between the tail end 22 and the top surface of the housing 3 is reasonably controlled to be between 24.6% and 32.0%. This ensures that the cover plate 1 does not interfere with the housing opening when welding to the negative electrode current collector 2, and also avoids interference or scratching of the housing wall when the negative electrode current collector 2 is bent into the housing, thus effectively improving the battery assembly yield and performance safety.

[0041] Specifically, in this embodiment, the shortest distance L31 between the connection point of the connecting part 23 and the protruding edge of the cover plate 1 and the top surface of the housing 3 is 15.45 mm, and L31 / L3 = 28.3%.

[0042] In this embodiment, the height of the shell 3 is H30, and it satisfies: L3 / H30 = 43.8%~47.6%.

[0043] In addition, the height H30 of the shell 3 is 114.6mm to 124.6mm.

[0044] It should be noted that when the ratio of L3 / H30 is less than the recommended 43.8% to 47.6%, the maximum vertical distance L3 between the tail end 22 and the top surface of the housing 3 is too small relative to the height H30 of the housing 3. L3 involves the distance from the edge of the tail end 22 to the bend. If this distance is too small, it will restrict the space of the welding area between the cover plate 1 and the tail end 22. Welding requires a certain amount of operating space to ensure the stable operation of the welding equipment and the welding quality. When the space is insufficient, the cover plate 1 can only be welded to the current collector on the outside of the housing opening. In order to meet the welding requirements, the position of the cover plate 1 will exceed the normal assembly range, thereby interfering with the housing opening and hindering the normal assembly of the battery.

[0045] When the ratio of L3 / H30 is greater than the recommended 43.8% to 47.6%, that is, when the maximum vertical distance L3 between the tail end 22 and the top surface of the housing 3 is too large relative to the height H30 of the housing 3, the negative electrode current collector 2 will be too long in the vertical direction. During the assembly process of bending the cover plate 1 into the housing, the negative electrode current collector 2 needs to be bent and deformed. The excessively long negative electrode current collector 2 will restrict the movement space at the bending point, and the bending part is prone to contact with the housing wall, causing interference or scratching. The metal shavings generated by the scratching will remain inside the battery, causing an internal short circuit in the battery. It will also affect the battery's self-discharge characteristics, resulting in a poor K value and reducing battery performance and safety.

[0046] In this embodiment, by reasonably controlling the ratio of the maximum vertical distance L3 between the tail end 22 and the top surface of the housing 3 to the height H30 of the housing 3 to be between 43.8% and 47.6%, it can be ensured that the cover plate 1 does not interfere with the housing opening when welding the negative electrode current collector 2, and at the same time avoid interference or scratching of the housing wall when the negative electrode current collector 2 is bent into the housing, thus effectively improving the battery assembly yield and performance safety.

[0047] Specifically, in this embodiment, the height H30 of the housing 3 is 119.6 mm.

[0048] In this embodiment, the diameter of the housing 3 is W30, and the maximum straight-line distance from the outer edge of the housing 3 to the connecting part 23 is W40, which satisfies: W40 / W30 = 77.8%~90.9%.

[0049] In addition, the diameter W30 of the shell 3 is 43mm to 49mm.

[0050] It should be noted that when the ratio of W40 / W30 is less than the recommended range, W40 is smaller than the diameter W30 of the casing 3, causing the root of the negative electrode current collector 2 to move inward. Since the maximum straight-line distance between the edge of the disk body 21 and the connecting part 23 becomes smaller, the contact area between the disk body 21 and the core 4 is reduced accordingly, resulting in a decrease in the effective welding area and an increase in the temperature rise at the welding line. At the same time, the reduction in the effective welding area will also lead to an increase in the internal resistance of the battery, affecting the battery performance.

[0051] When the ratio of W40 / W30 is greater than the recommended range, the root of the negative current collector 2 will move outward. During the assembly process, the two sides of the bending width direction of the root of the negative current collector 2 will interfere or scratch with the shell wall of the housing 3. Interference and scratching will not only affect the normal assembly of the battery and reduce the assembly yield, but also the metal shavings generated during the scratching process will remain inside the battery. The metal shavings may cause an internal short circuit in the battery, and will also affect the self-discharge characteristics of the battery, resulting in poor K value and reducing the performance and safety of the battery.

[0052] In this embodiment, by reasonably controlling the ratio of the maximum straight-line distance W40 from the outer edge of the housing 3 to the connecting part 23 to the diameter W30 of the housing 3 to be between 77.8% and 90.9%, it can ensure that the disc part 21 and the core 4 have sufficient effective welding area, reduce the temperature rise at the welding line and the internal resistance of the battery, and avoid interference or scratching between the negative electrode current collector 2 and the housing wall to generate metal chips, thereby effectively improving battery performance and assembly yield.

[0053] Specifically, in this embodiment, the maximum straight-line distance W40 from the outer edge of the housing 3 to the connecting part 23 is 38.8 mm, and the diameter of the housing 3 is W30 = 46 mm.

[0054] In this embodiment, the width of the connecting part 23 is W, and it satisfies: W = 26mm ~ 30mm.

[0055] It should be noted that when the width W of the connection part 23 is too small, the current carrying capacity of the connection part 23 is weakened, and the heat generated by the connection part 23 will increase significantly. When the temperature reaches a certain level, the connection part 23 is prone to melting, causing the battery circuit to be interrupted and the battery to fail. At the same time, the large amount of heat generated will cause the overall temperature inside the battery to rise, affecting the performance of the battery.

[0056] When the width W of the connecting part 23 is too large, the dimension of the bent negative current collector 2 perpendicular to the bending direction will increase accordingly. Since the internal space of the housing 3 is limited, the excessive size will reduce the distance between the bent part of the negative current collector 2 and the housing wall, making it easy for interference or scratches to occur, affecting the normal assembly of the battery and reducing the assembly yield. Moreover, the metal shavings generated during the scratching process will remain inside the battery, causing an internal short circuit and preventing the battery from working properly. At the same time, the presence of metal shavings will also affect the self-discharge characteristics of the battery, resulting in a poor K value of the battery and reducing the performance and safety of the battery.

[0057] In this embodiment, by reasonably controlling the width W of the connecting part 23 to be between 26mm and 30mm, it is possible to ensure that the connecting part 23 has sufficient current carrying capacity, avoid battery failure due to heat generation and melting during high-rate charging and discharging, and prevent interference or scratching with the shell wall after bending to generate metal shavings, thereby effectively improving battery performance and assembly yield.

[0058] Specifically, in this embodiment, W = 28 mm.

[0059] In this embodiment, the maximum width of the tail end 22 is D30, and satisfies: D30 = 35.2mm ~ 39.2mm.

[0060] It should be noted that when the maximum width D30 of the tail end 22 is too small, the area of ​​the welding between the tail end 22 and the cover plate 1 is reduced. During the charging and discharging process of the battery, when the current passes through the welding line, due to the reduction of the effective conductive area, more heat will be generated when the current passes through, which will increase the temperature rise of the welding point and affect the performance of the battery.

[0061] In actual production processes, a certain reasonable offset is necessary to ensure smooth assembly and welding. When the maximum width D30 of the connecting end 22 is too large, the positioning accuracy requirements of the production equipment will increase significantly. This is because the equipment needs to precisely position and weld the connecting end 22 to the cover plate 1. If the positioning is inaccurate, welding deviations and other problems can easily occur, increasing production difficulty and manufacturing costs. Furthermore, after welding is completed, the cover plate 1 needs to be inserted into the casing to complete the final assembly of the battery. If the maximum width D30 of the connecting end 22 is too large, the size of the connecting end 22 will exceed the normal range, which may cause interference with the casing opening during the casing insertion process, hindering the smooth insertion of the cover plate, affecting the assembly yield, and even potentially damaging the battery.

[0062] In this embodiment, by reasonably controlling the maximum width D30 of the tail end 22 between 35.2mm and 39.2mm, it can ensure that the tail end 22 and the cover plate 1 have sufficient welding area, reduce the temperature rise at the welding point, improve battery performance, adapt to reasonable offset in the production process, reduce the requirements for equipment positioning accuracy, reduce manufacturing costs, and at the same time avoid interference between the cover plate 1 and the shell opening when it is inserted into the shell, thereby improving the assembly yield.

[0063] Specifically, in this embodiment, the maximum width D30 of the control tail end 22 is 37.2 mm.

[0064] In this embodiment, the area of ​​the tab end face of the core 4 is S40, and the area of ​​the disc body 21 covering the core 4 is S41, and satisfies: S41 / S40 = 71.4%~81.4%.

[0065] It should be noted that when the ratio of the area S41 of the disc portion 21 covering the core 4 to the area S40 of the tab end face of the core 4 is too small, the contact range between the disc portion 21 and the core 4 is limited. During the welding process, the welding quality depends on sufficient contact area to ensure the strength and stability of the weld wire. When the area S41 of the disc portion 21 covering the core 4 is too small, the effective welding area is reduced, resulting in an increase in temperature at the weld wire, which in turn affects the battery performance. At the same time, the reduction in the effective welding area will also increase the internal resistance of the battery, affecting the battery's charging and discharging efficiency and energy output.

[0066] If the area S41 of the disk portion 21 covering the core 4 is too large, it may be necessary to increase the area of ​​the disk surface of the disk portion 21. However, in actual production, there is a certain reasonable welding process deviation. When the area of ​​the disk surface of the disk portion 21 is increased, the edge of the disk surface is prone to interference with the inner diameter of the battery case during the assembly process. An excessively large area of ​​the disk portion 21 may also cause the root to shift outward. During the assembly process of bending the negative electrode current collector 2 to insert the cover plate 1 into the case, the distance between the two sides of the root bending width direction and the case wall will become smaller, which is prone to interference or scratching, affecting the assembly yield. Moreover, the metal shavings generated during the scratching process will remain inside the battery, causing an internal short circuit in the battery and preventing the battery from working properly.

[0067] In this embodiment, by reasonably controlling the ratio of the area S41 of the disk body 21 covering the core 4 to the area S40 of the tab end face of the core 4 to be between 71.4% and 81.4%, it can ensure that the current collector disk body 21 and the core 4 have sufficient effective welding area, reduce the temperature rise at the welding line and the internal resistance of the battery, and improve the battery performance. At the same time, it can avoid the disk surface being too large and interfering with the inner diameter of the shell or the root moving outward and scraping against the shell wall to generate metal chips, effectively improving the battery assembly yield and safety.

[0068] Specifically, in this embodiment, the area S40 of the tab end face of the core 4 is 1547.5 mm². 2The area S41 of the core 4 covered by the disc body 21 is 1181.9 mm². 2 .

[0069] The above description is only a preferred embodiment of the present utility model and is not intended to limit the present utility model. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present utility model should be included within the protection scope of the present utility model.

Claims

1. A cylindrical secondary battery, characterized in that, It includes a cover plate (1), a negative electrode current collector (2), a housing (3), and a core (4). The shell (3) is hollow inside, and the core (4) is disposed inside the shell (3); The negative electrode current collector (2) includes a disk body (21), a tail end (22) and a connecting part (23), and the two sides of the connecting part (23) are fixedly connected to the disk body (21) and the tail end (22) respectively. The disc body (21) is fixedly connected to the end face of the tab of the core (4), and the tail end (22) is fixedly connected to the cover plate (1); The maximum vertical distance between the tail end (22) and the top surface of the shell (3) is L3, and the maximum vertical distance between the connecting part (23) and the top surface of the shell (3) is L30, satisfying: L30 / L3=59.7%~70.7%.

2. The cylindrical secondary battery as described in claim 1, characterized in that: The shortest distance between the connection point of the connecting part (23) and the protruding edge of the cover plate (1) and the top surface of the shell (3) is L31, which satisfies: L31 / L3 = 24.6%~32.0%.

3. The cylindrical secondary battery as described in claim 1, characterized in that: The maximum vertical distance L3 between the tail end (22) and the top surface of the shell (3) is 51.6 mm to 57.6 mm.

4. The cylindrical secondary battery as described in claim 1, characterized in that: The height of the shell (3) is H30, and satisfies: L3 / H30 = 43.8% to 47.6%.

5. The cylindrical secondary battery as described in claim 1, characterized in that: The diameter of the housing (3) is W30, and the maximum straight-line distance from the outer edge of the housing (3) to the connecting part (23) is W40, and satisfies: W40 / W30 = 77.8%~90.9%.

6. The cylindrical secondary battery as described in claim 5, characterized in that: The diameter W30 of the shell (3) is 43mm to 49mm.

7. The cylindrical secondary battery as described in claim 1, characterized in that: The width of the connecting part (23) is W, and satisfies: W = 26mm ~ 30mm.

8. The cylindrical secondary battery as described in claim 1, characterized in that: The maximum width of the tail end (22) is D30, and satisfies: D30 = 35.2mm ~ 39.2mm.

9. The cylindrical secondary battery as described in claim 1, characterized in that: The area of ​​the tab end face of the core (4) is S40, and the area of ​​the disc body (21) covering the core (4) is S41, and satisfies: S41 / S40 = 71.4%~81.4%.

10. The cylindrical secondary battery as described in claim 4, characterized in that: The height H30 of the shell (3) is 114.6 mm to 124.6 mm.

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