Cylindrical battery and battery pack

Abstract

The utility model relates to the technical field of battery design, and discloses a cylindrical battery and a battery pack, the cylindrical battery comprises a shell, a battery cell, a pole and an electric connecting piece, the shell is provided with a first wall along the height direction of the cylindrical battery, the first wall is provided with a first surface and a second surface which are oppositely arranged, and a groove bottom wall is formed between a groove in the first surface and the second surface; the groove bottom wall forms a weak area; the pole is electrically connected with the battery cell, and the first surface is the surface, far away from the battery cell, of the first wall; the electric connecting piece is connected with the pole, and a welding mark formed by welding the electric connecting piece and the first wall is formed in the groove. According to the utility model, the welding of the electric connecting piece and the first wall is realized by welding at the groove, and the weak area is formed by the groove bottom wall of the groove so as to release pressure when the battery is in thermal runaway, so that the integrated arrangement of the explosion-proof valve and the welding groove is realized, the occupation of the area of the first surface is reduced, and the residual area of the first surface is increased; and the layout design of other parts of the battery on the first wall is facilitated.

Description

Technical Field

[0001] This utility model relates to the field of battery design technology, specifically to cylindrical batteries and battery packs. Background Technology

[0002] With the rapid development of new energy technologies, cylindrical batteries have secured a significant position in the energy storage field due to their unique advantages. The heat generated during charging and discharging of cylindrical batteries can be distributed more evenly across the battery surface, reducing the risk of localized overheating and leading to their widespread application in various sectors.

[0003] In existing technology, to ensure battery safety, explosion-proof valve markings are provided on the cover plate. When the internal pressure of the battery abnormally increases, the explosion-proof valve markings will rupture first, releasing the internal pressure and preventing accidents. Furthermore, welding grooves are provided on the cover plate to facilitate welding between the cover plate and electrical connectors. However, having both explosion-proof valve markings and welding grooves on the cover plate occupies a large area, resulting in limited remaining space and hindering the layout of other components on the cover plate. Utility Model Content

[0004] In view of this, the present invention provides a cylindrical battery and battery pack to solve the problem that the simultaneous setting of explosion-proof valve grooves and welding grooves results in a small remaining space on the cover plate, which is inconvenient for the layout of other components on the cover plate.

[0005] In a first aspect, this utility model provides a cylindrical battery, comprising:

[0006] The outer casing has a cavity within it. The outer casing has a first wall along the axial direction of the cylindrical battery. The first wall has a first surface and a second surface arranged opposite each other along the axial direction. A groove is formed on the first surface, and a bottom wall is formed on the remaining portion of the first wall along the axial direction. The bottom wall forms a weak area suitable for venting gas from the cavity during thermal runaway. A battery cell is disposed within the cavity, with the first surface being the side of the first wall away from the battery cell. An electrical connector is disposed within the cavity and electrically connected to the outer casing. The electrical connector is welded to the first wall to form a solder mark, which is located within the groove.

[0007] Beneficial effects: By welding at the groove, the electrical connector is welded to the first wall, and a weak area is formed at the bottom wall of the groove to release pressure in case of battery thermal runaway. This achieves the integration of the explosion-proof valve and the welding groove, reducing the area occupied on the first surface and increasing the remaining area of ​​the first surface, which facilitates the layout design of other battery components on the first wall.

[0008] Secondly, this utility model also provides a battery pack, including the above-mentioned cylindrical batteries and busbars, wherein a plurality of cylindrical batteries are provided; the busbars are connected to the housing and connect to at least two of the cylindrical batteries.

[0009] Beneficial effects: By using the above-mentioned cylindrical battery, the available welding area between the busbar and the first wall of the cylindrical battery is increased, thereby ensuring the welding quality between the busbar and the first wall and guaranteeing the battery assembly yield. Attached Figure Description

[0010] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0011] Figure 1 This is a schematic diagram of the overall structure of the cylindrical battery according to an embodiment of the present invention;

[0012] Figure 2 This is a top view of the cylindrical battery according to an embodiment of the present invention.

[0013] Figure 3 for Figure 2 A cross-sectional view of XX.

[0014] Explanation of reference numerals in the attached figures:

[0015] 10. Outer shell; 11. Housing; 12. Plate; 13. Groove; 20. Battery cell; 30. Terminal post; 40. Electrical connector; 50. Groove bottom wall; 60. Solder mark. Detailed Implementation

[0016] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.

[0017] The following is combined Figures 1 to 3 The following describes embodiments of the present invention.

[0018] According to an embodiment of the present invention, in a first aspect, a cylindrical battery is provided, comprising: a housing 10, a battery cell 20, and an electrical connector 40. The housing 10 has a receiving cavity formed therein. The housing 10 has a first wall along the axial direction of the cylindrical battery. The first wall has a first surface and a second surface arranged opposite to each other along the axial direction. A groove 13 is formed on the first surface, and a groove bottom wall 50 is formed on the remaining portion of the first wall along the axial direction. The groove bottom wall 50 forms a weak area, which is suitable for venting gas inside the receiving cavity in the event of thermal runaway. The battery cell 20 is disposed in the receiving cavity, and the first surface is the side of the first wall away from the battery cell 20. The electrical connector 40 is disposed in the receiving cavity and is electrically connected to the housing 10. The electrical connector 40 is welded to the first wall to form a solder mark 60, which is located in the groove 13.

[0019] The cylindrical battery of this embodiment is welded at the groove 13 to achieve the welding of the electrical connector 40 to the first wall. The bottom wall 50 of the groove 13 forms a weak area to release pressure in the event of thermal runaway of the battery. This achieves the integration of the explosion-proof valve and the welding groove 13, reducing the area occupied on the first surface and increasing the remaining area of ​​the first surface, which facilitates the layout design of the other battery components on the first wall.

[0020] It should be noted that in related technologies, explosion-proof valve markings and welding grooves 13 are provided on the battery cover plate. These markings and grooves occupy a portion of the cover plate, resulting in less remaining space and hindering the connection layout between the first wall and other components. However, this application integrates the explosion-proof valve and the welding groove 13. A single groove 13 can both facilitate the welding of the electrical connector 40 to the first wall and ensure heat release capacity during thermal runaway, increasing the usable area of ​​the first wall for other components and facilitating the layout design of the remaining battery components on the first wall.

[0021] It is worth noting that the bottom wall 50 of the battery tank serves as a weak point on the outer casing 10. When the battery experiences thermal runaway or other safety issues, the increased internal pressure forces the weak point to break through, releasing the internal gas and preventing further thermal runaway that could lead to a battery explosion or other serious accidents. In other words, the bottom wall 50 of the battery tank functions as an explosion-proof valve.

[0022] It should be noted that the explosion-proof valve is typically located on the battery casing 10 and can monitor changes in internal battery pressure in real time. When the internal battery pressure reaches or exceeds a preset threshold, the explosion-proof valve automatically opens to release accumulated gas, thus preventing the battery from rupturing or exploding due to excessive pressure. When the internal battery pressure is below the preset threshold, the explosion-proof valve remains closed, allowing the battery to operate normally. The grooves on the explosion-proof valve are special indentations formed during the manufacturing process through a stamping process. These grooves increase the surface area of ​​the explosion-proof valve, helping to better diffuse gas and dissipate heat, thereby relieving internal pressure and releasing gas in the event of abnormal battery conditions, preventing battery explosion or fire.

[0023] It should be noted that the outer casing 10 is used to encapsulate the battery cell 20 and electrolyte components. The shape of the outer casing 10 can be determined according to the specific shape and size of the battery cell 20. The material of the outer casing 10 can be various, including but not limited to copper, iron, aluminum, stainless steel, aluminum alloy, plastic, etc.

[0024] It should be noted that cell 20 is the smallest charging and discharging unit. Cell 20 has a positive electrode, a negative electrode, and a separator between them. The cell body is formed by winding or stacking. The positive electrode includes a positive current collector and a positive active material. The positive current collector can be made of metal materials such as aluminum foil, nickel foil, and stainless steel, or a composite foil formed by combining metal and insulating materials. The positive active material includes a positive active material, a conductive agent, and a binder. The positive active material includes one or more of lithium-containing positive active materials such as lithium iron phosphate, ternary materials containing nickel, cobalt, and manganese, and lithium manganese iron phosphate. Similarly, the negative electrode includes a negative current collector and a negative active material. The negative current collector can be made of metal materials such as copper foil, aluminum foil, and stainless steel, or a composite foil formed by combining metal and insulating materials. The negative active material includes a negative active material, a conductive agent, and a binder. The negative active material includes one or more of negative active materials such as artificial graphite, natural graphite, silicon carbide, silicon oxide, and lithium titanate. The tabs serve as the current output terminals of the cell 20, and are either integrally connected to the positive or negative electrode or connected separately. The separator, as an insulating layer, prevents short circuits within the battery cell caused by contact between the positive and negative electrodes, and as a semi-permeable layer, it prevents larger molecules from passing through while allowing smaller charged ions to pass through.

[0025] It should be noted that the electrical connector 40 is a thin metal sheet, usually made of copper or aluminum foil. The electrical connector 40 is used to connect the active material to the external circuit, allowing current to flow smoothly.

[0026] Specifically, in this embodiment, the bottom wall 50 of the groove is an annular structure, and the groove 13 has a bottom plane 131, a first side wall 132 and a second side wall 133. The side of the bottom wall 50 away from the second surface is the bottom plane 131. The bottom plane 131 is connected to the first side wall 132 and the second side wall 133 to enclose and form the groove 13.

[0027] Specifically, in this embodiment, the electrical connector 40 is a collector plate.

[0028] In other alternative embodiments, the electrical connector 40 may also be a tab or other structure.

[0029] In one embodiment, such as Figure 2 As shown, the groove 13 is continuously arranged along the circumference of the first surface. That is, the groove 13 is arranged around the entire circumference of the first surface.

[0030] Specifically, such as Figure 2 As shown, in this embodiment, the groove 13 is continuously arranged circumferentially along the first surface to form an annular groove 13.

[0031] It is worth noting that the air pressure in the containment cavity is relatively uniform throughout the continuously arranged grooves 13, avoiding local pressure concentration. When the predetermined pressure is reached inside the battery, the bottom wall 50 of the groove can be broken evenly, thereby improving the pressure relief effect of the battery and improving the battery safety.

[0032] In other alternative embodiments, the groove 13 is segmented along the circumference of the first surface. That is, the groove 13 is not arranged along the entire circumference of the first surface. This arrangement enables the first wall to have better structural strength and withstand greater pressure from the outside of the battery during normal use of the cylindrical battery.

[0033] For example, four grooves 13 are provided, and the four grooves 13 are evenly spaced along the circumference of the first surface.

[0034] It should be noted that those skilled in the art can select the arrangement scheme of the groove 13 according to actual needs.

[0035] In one embodiment, the bottom wall 50 of the tank is set to a non-uniform thickness along the circumference of the first surface, with the minimum thickness of the bottom wall 50 being Lmin and the maximum thickness being Lmax, satisfying 0.3≤Lmin / Lmax<1.

[0036] It should be noted that the electrical connector 40 is partially welded to the bottom wall 50 of the tank. In order to balance the welding strength and the use requirements of the explosion-proof valve, the bottom wall 50 of the tank is set to a non-uniform thickness. That is, the thickness of the bottom wall 50 of the tank is inconsistent at various angles along the circumference of the first surface. The thicker part of the bottom wall 50 is welded to the electrical connector 40, and the thinner part of the bottom wall 50 serves as the explosion-proof valve.

[0037] It should be noted that the minimum thickness Lmin of the bottom wall 50 of the tank should not be too small relative to the maximum thickness Lmax, in order to ensure that its air pressure resistance meets the requirements.

[0038] Optionally, the ratio of Lmin / Lmax can be any value from 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 0.99, or any value between two of these values.

[0039] In one embodiment, such as Figure 2 As shown, the solder mark 60 and the bottom wall 50 of the tank are partially overlapped. The length of the solder mark 60 along the first surface is C1, and the length of the bottom wall 50 along the first surface is C2, satisfying C1 < C2.

[0040] Furthermore, the ratio of the length C1 of the solder mark 60 along the first surface circumferential direction to the length C2 of the bottom wall 50 of the groove along the first surface circumferential direction satisfies 0.3≤C1 / C2≤0.6.

[0041] It should be noted that the length C1 of the solder mark 60 along the circumferential direction of the first surface is as follows: Figure 2 As shown, the bottom wall 50 of the tank is continuously arranged circumferentially along the first surface.

[0042] It should be noted that the length of the solder mark 60 along the circumference of the first surface is also the length of the welding area along the circumference of the first surface. In this embodiment, the solder mark 60 only partially overlaps with the bottom wall 50 of the groove, that is, the solder mark 60 does not cover the entire groove 13.

[0043] It should be noted that when C1 / C2 < 0.3, the welding strength between the electrical connector 40 and the bottom wall 50 of the tank is low and does not meet the strength requirements; when C1 / C2 > 0.6, the welding area is too large, and the thinner part of the bottom wall 50 used as an explosion-proof valve is less, which does not meet the exhaust requirements in case of thermal runaway.

[0044] Optionally, the ratio of C1 / C2 can be any value among 0.3, 0.4, 0.5, and 0.6, or a value between any two values.

[0045] In one embodiment, such as Figure 3 As shown, the width of the solder mark 60 along the radial direction of the first surface is W1, and the width of the bottom wall 50 along the radial direction of the first surface is W2, satisfying W1≤W2.

[0046] Furthermore, the ratio of the radial width W1 of the solder mark 60 along the first surface to the radial width W2 of the bottom wall 50 along the first surface satisfies 0.2≤W1 / W2≤1.

[0047] Specifically, in this embodiment, such as Figure 3 As shown, the width W1 of the solder mark 60 along the radial direction of the first surface is smaller than the width W2 of the bottom wall 50 along the radial direction of the first surface.

[0048] Of course, in other alternative embodiments, the width W1 of the solder mark 60 along the radial direction of the first surface can also be equal to the width W2 of the bottom wall 50 along the radial direction of the first surface.

[0049] It should be noted that when W1 / W2 < 0.2, the welding strength between the electrical connector 40 and the bottom wall 50 of the tank is low and does not meet the strength requirements.

[0050] Optionally, the ratio of W1 / W2 can be any value from 0.2, 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, or a value between any two values.

[0051] In one embodiment, such as Figure 3 As shown, along the axial direction of the cylindrical battery, the thickness of the bottom wall 50 of the groove is L, which satisfies 0.05mm≤L≤0.4mm.

[0052] It should be noted that when the thickness L of the bottom wall 50 is less than 0.05 mm, the bottom wall 50 is too thin. During the welding process between the first wall and the electrical connector 40, the welding process may cause the bottom wall 50 to deform, and the welding strength between the first wall and the electrical connector 40 may be insufficient. When the thickness L of the bottom wall 50 is greater than 0.4 mm, the bottom wall 50 is too thick. An excessively thick bottom wall 50 has an excessively high pressure resistance. When the pressure inside the outer shell 10 is abnormal, it is not easy to be broken through to relieve the pressure. Furthermore, other parts of the outer shell 10, except for the bottom wall 50, may not be able to withstand the pressure and may break before the bottom wall 50.

[0053] It is worth noting that by limiting the thickness of the bottom wall 50 of the groove, the pressure of the groove 13 can be released normally and in a timely manner under abnormal conditions such as thermal runaway, while ensuring the welding strength between the first wall and the electrical connector 40.

[0054] Optionally, the thickness L of the bottom wall 50 of the tank can be any value or a value between any two of the following: 0.05mm, 0.08mm, 0.1mm, 0.12mm, 0.15mm, 0.18mm, 0.2mm, 0.22mm, 0.25mm, 0.28mm, 0.3mm, 0.32mm, 0.35mm, 0.38mm, and 0.4mm.

[0055] In one embodiment, the outer casing 10 includes a housing 11 and a plate 12. The housing 11 has an opening, and the plate 12 is connected to the housing 11 and seals the opening to enclose and form a receiving cavity. The plate 12 forms a first wall.

[0056] It is worth noting that both ends of the casing 11 have openings, which are sealed by two plates 12. In this case, one plate 12 is welded to the casing 11, and the other plate 12 is integrally formed with the casing 11; alternatively, one plate 12 is welded to the casing 11, and the other plate 12 is also welded to the casing 11. Furthermore, the cylindrical battery may have grooves 13 on both plates 12 to form weak areas, thereby improving the safety of the cylindrical battery.

[0057] Furthermore, such as Figure 1 As shown, in one embodiment, the plate 12 is welded to the shell 11, and the thickness L of the bottom wall 50 of the groove satisfies 0.05mm≤L≤0.3mm.

[0058] It should be noted that plate 12 refers to the component that covers the opening of housing 11 to isolate the accommodating space from the external environment. The shape of plate 12 can be adapted to the shape of housing 11 to fit the housing. Plate 12 can be made of a material with a certain hardness and strength (such as aluminum alloy).

[0059] It should be noted that the plate 12 and the shell 11 are connected by welding to form the outer shell 10. Since the thickness of the plate 12 is usually greater than the thickness of the shell 11, the thickness of the bottom wall 50 of the tank is further reduced to ensure that when the cylindrical battery runs away from thermal control, the bottom wall 50 of the tank will break down and release heat first, thus ensuring the welding stability of the plate 12 and the shell 11.

[0060] In another embodiment, the plate 12 and the shell 11 are integrally formed, and the thickness L of the bottom wall 50 of the groove satisfies 0.08mm≤L≤0.4mm.

[0061] It should be noted that the unibody shell 10 has a high overall structural strength. The shell 10 has no splicing or connection gaps, and there is no problem of strength weakening due to loosening, misalignment or gaps at the welding points. Therefore, when the internal pressure of the battery is too high, the gas inside the battery will break through the bottom wall 50 of the tank, but will not break the connection between the plate 12 and the shell 11. This allows the thickness of the bottom wall 50 to be relatively increased, thereby improving the structural strength of the bottom wall 50 and preventing accidental valve opening when the battery is squeezed, collided or vibrated, thus ensuring the pressure relief effect in the weak area.

[0062] In one embodiment, the housing 11 is an aluminum housing, and the thickness L of the bottom wall 50 of the groove satisfies 0.1mm≤L≤0.3mm.

[0063] It should be noted that during charging or thermal runaway, the cell 20 expands in volume, leading to increased pressure within the containment cavity. This increased pressure can cause rapid deformation of the bottom wall 50, such as bulging or bending. In the design and manufacturing of cylindrical batteries, material selection plays a crucial role in battery performance. Because the aluminum casing 11 has relatively low hardness and strength, the bottom wall 50 may prematurely break and release heat before the pressure within the containment cavity reaches the predetermined pressure. Therefore, when the casing 11 is made of aluminum, the bottom wall 50 needs to be thicker to improve the stability of the entire groove 13 structure, ensuring that the groove 13 of the aluminum casing only ruptures and releases heat after reaching the predetermined pressure.

[0064] In another embodiment, the housing 11 is a steel shell, and the thickness L of the bottom wall 50 of the groove satisfies 0.05mm≤L≤0.2mm.

[0065] It should be noted that the steel shell 11 exhibits unique advantages in terms of hardness and strength. Steel, a widely used metal material in industrial fields, possesses excellent mechanical properties after special processing and treatment. Its internal crystal structure is dense and ordered, with strong interatomic bonding, giving steel high hardness and strength. This allows the steel shell 11 to maintain good stability when facing various external forces and internal pressures. Compared to aluminum shells, the deformation of the steel shell is less when the pressure inside the cavity increases. Therefore, when the shell 11 is made of steel, the thickness of the bottom wall 50 can be reduced to ensure that the bottom wall 50 can rupture and release heat in a timely manner.

[0066] In one embodiment, such as Figure 3 As shown, along the radial direction of the first surface, the groove width of the groove 13 is W, which satisfies 0.8mm≤W≤1.5mm.

[0067] It should be noted that when the groove width W of groove 13 is less than 0.8 mm, the groove width of groove 13 is too narrow. When the battery experiences thermal runaway, internal gas is rapidly generated and accumulates a large amount of pressure. The narrow groove width of groove 13 obstructs gas discharge, preventing timely and sufficient pressure release. At the same time, the pressure distribution on the bottom wall 50 of the groove is more likely to be uneven. Differences in structural strength will cause uneven pressure on different parts of the bottom wall 50. When the internal pressure of the battery rises, some weak points of groove 13 may rupture prematurely, affecting the battery's safety performance. When the groove width W of groove 13 is greater than 1.5 mm, the groove width of groove 13 is too wide, causing groove 13 to occupy too much area on the first surface, resulting in a smaller welding area between the first surface and the busbar. In addition, the excessively wide groove 13 has a certain weakening effect on the overall structural strength of the plate 12. Furthermore, the excessively wide groove width of groove 13 means that more material needs to be removed during the manufacturing process, which will increase the consumption of raw materials and increase production costs.

[0068] Optionally, the groove width W of the groove 13 can be any value among 0.8mm, 0.9mm, 1.0mm, 1.1mm, 1.2mm, 1.3mm, 1.4mm, and 1.5mm, or a value between any two of these values.

[0069] It should be noted that the groove width W of the groove 13 is equal to the width W2 of the groove bottom wall 50 along the first surface radially.

[0070] It should be noted that a bus is a component that connects multiple cylindrical batteries, and is usually made of conductive materials such as copper and aluminum. Buses are used to transmit electrical energy and signals between multiple cylindrical batteries. Buses can enable multiple cylindrical batteries to be connected in series or in parallel.

[0071] It is worth noting that by limiting the width of the groove 13, the remaining area of ​​the first wall is ensured, thereby ensuring the welding area between the first wall and the electrical connection piece, and ensuring that the groove 13 has a sufficient pressure relief area so that pressure relief and heat release can be carried out quickly when thermal runaway occurs in the cylindrical battery.

[0072] In one embodiment, such as Figure 3 As shown, along the axial direction of the cylindrical battery, the groove depth of groove 13 is T, which satisfies 0.2mm≤T≤0.8mm.

[0073] It should be noted that when the groove depth T of groove 13 is less than 0.2 mm, the groove depth is too small. When the pressure inside the battery rises sharply due to thermal runaway or other reasons, it is difficult for groove 13 to break down and release heat quickly. When the groove depth T of groove 13 is greater than 0.8 mm, the groove depth is too large, resulting in a larger thickness of plate 12. This can easily lead to plate 12 squeezing the cell 20, and also cause plate 12 to occupy too much axial space of the cylindrical battery, affecting the space utilization rate of the battery. At the same time, an excessively large groove depth means that more material needs to be removed during the manufacturing process, reducing production efficiency.

[0074] Optionally, the groove depth T of the groove 13 can be any value among 0.2mm, 0.4mm, 0.6mm, 0.65mm, 0.70mm, 0.75mm, and 0.8mm, or a value between any two of these values.

[0075] It is worth noting that in this embodiment, the groove depth of the groove 13 is made to satisfy 0.2mm≤T≤0.8mm. This ensures that the explosion-proof valve can be opened normally, while preventing the groove depth of the groove 13 from being too high and thus squeezing the battery cell 20.

[0076] In one embodiment, such as Figure 3 As shown, along the radial direction of the first surface, the distance from the groove 13 to the outer peripheral edge of the first wall is A, which satisfies 1mm≤A≤5mm.

[0077] It should be noted that when the distance A from the groove 13 to the outer peripheral edge of the first wall is less than 1 mm, the groove 13 is too close to the outer peripheral edge of the plate 12. When the plate 12 is assembled with the shell 11, the stress on the plate 12 near the outer peripheral edge is relatively concentrated, which can easily cause the plate 12 to deform and thus affect the subsequent assembly of the plate 12 with the shell 11. When the distance A from the groove 13 to the outer peripheral edge of the first wall is greater than 5 mm, the distance between the groove 13 and the protrusion 31 is small. When the groove 13 is used to perform welding operations between the first wall and the electrical connector 40, it can easily affect the pole post 30.

[0078] Optionally, the distance A from the groove 13 to the outer peripheral edge of the first wall can be any value among 1mm, 1.1mm, 1.5mm...4.5mm, 5mm, or a value between any two values.

[0079] It is worth noting that by limiting the distance between the second groove sidewall 133 and the outer peripheral edge of the first wall, the groove 13 is prevented from being too close to the outer peripheral edge of the first wall, which would cause the plate 12 to deform and affect the assembly of the plate 12 and the housing 11. It also prevents the welding operation between the first wall and the electrical connector 40 from affecting the pole post 30.

[0080] In one embodiment, such as Figure 2 As shown, the cylindrical battery also includes an electrode post 30, which is disposed on the first wall. Along the radial direction of the first surface, the distance between the electrode post 30 and the groove 13 is B, which satisfies 5mm≤B≤10mm.

[0081] It should be noted that terminal 30 is the current output terminal of the cylindrical battery.

[0082] Optionally, the distance B between the pole post 30 and the groove 13 can be any value of 5mm, 5.1mm, 6mm, 6.5mm, 7mm, 7.5mm, 8mm, or 10mm, or a value between any two of these values.

[0083] Specifically, the pole post 30 is provided with an insulating component to facilitate insulation between the pole post 30 and the outer casing 10.

[0084] It should be noted that, from the perspective of welding process, when using the groove 13 to weld the first wall and the electrical connector 40, if the distance between the groove 13 and the pole post 30 is too close, the welding slag generated during the welding process may splash onto the insulating parts on the pole post 30, and the heat generated during welding has a significant impact on the insulating parts. As the core component for isolating the charged parts of the battery and ensuring electrical insulation performance, the insulating parts are mostly made of high-molecular polymers and other materials that are not resistant to high temperatures. Once exposed to high temperatures or mechanical damage, the physical and chemical properties of the insulating layer will be destroyed, causing the cylindrical battery to fail in insulation. Furthermore, if the distance between the groove 13 and the terminal 30 is too small, it will also cause the welding area of ​​the busbar to be too small, thereby affecting the welding stability between the first wall and the busbar. As the distance between the terminal 30 and the groove 13 gradually increases, the groove 13 gradually approaches the outer peripheral edge of the body. When the plate 12 is welded to the shell 11, the stress on the plate 12 near the outer peripheral edge is more concentrated, which can easily cause the plate 12 to deform, thereby affecting the subsequent assembly of the plate 12 and the shell 11.

[0085] It is worth noting that by limiting the distance between the pole post 30 and the groove 13, damage to the insulating parts on the pole post 30 is avoided when welding the first wall and the electrical connector 40, and a certain safe distance is left around the welding area, thereby ensuring the welding yield of the first wall busbar.

[0086] In one embodiment, the electrical connector 40 is a positive current collector, one side of the electrical connector 40 is electrically connected to the housing 10, and the other side of the electrical connector 40 is electrically connected to the positive electrode tab of the battery cell 20. The electrical connector 40 is arranged in a fan shape.

[0087] In other alternative embodiments, the electrical connector 40 may also be a negative current collector, with one side of the electrical connector 40 electrically connected to the housing 10 and the other side of the electrical connector 40 electrically connected to the negative electrode tab of the battery cell 20.

[0088] In one embodiment, such as Figure 3 As shown, along the axial direction of the cylindrical battery, the height of cell 20 is H, which satisfies 70mm≤H≤160mm.

[0089] Optionally, the height H of the battery cell 20 can be any value among 70mm, 75mm, 80mm, 85mm, 90mm, 100mm, 110mm, 120mm, 140mm, and 160mm, or a value between any two of these values.

[0090] It should be noted that the battery cell 20 generates heat during charging and discharging. The higher the battery cell 20 is, the more heat is generated, and the greater the pressure inside the casing 11 will be. The thickness of the bottom wall 50 of the slot needs to be adjusted according to the height of the battery cell 20. When the height of the battery cell 20 is too high, a thinner bottom wall 50 needs to be selected so that the bottom wall 50 can open in the event of thermal runaway. When the height of the battery cell 20 is small, the thickness of the bottom wall 50 can be appropriately increased to increase the overall structural strength of the casing 10.

[0091] According to an embodiment of the present invention, in a second aspect, a battery pack is also provided, including the above-mentioned cylindrical batteries and a busbar, wherein a plurality of cylindrical batteries are provided; the busbar is connected to the housing 10 and connects at least two cylindrical batteries.

[0092] The battery pack of this embodiment increases the available welding area between the busbar and the first wall of the cylindrical battery by using the above-mentioned cylindrical battery, thereby ensuring the welding quality between the busbar and the first wall and guaranteeing the battery assembly yield.

[0093] Furthermore, the busbar is welded between the groove 13 and the pole 30.

[0094] It is worth noting that the busbar is typically attached to the first surface of the housing 10 and welded to the first surface to achieve electrical connection. In related technologies, the explosion-proof valve markings and welding grooves 13 occupy a portion of the first surface, resulting in a smaller remaining space on the first surface. This means the area available for welding the busbar is too small, leading to lower welding reliability between the housing 10 and the busbar, and affecting the current-carrying capacity between them. In this embodiment, by integrating the explosion-proof valve with the welding grooves 13, the area occupied on the first surface is reduced, thus reserving sufficient area for welding the busbar. This improves the welding reliability between the housing 10 and the busbar and enhances the current-carrying capacity between them, meeting the current requirements of high-capacity batteries.

[0095] Although embodiments of the present invention have been described in conjunction with the accompanying drawings, those skilled in the art can make various modifications and variations without departing from the spirit and scope of the present invention, and such modifications and variations all fall within the scope defined by the present invention.

Claims

1. A cylindrical battery, characterized in that, include: The outer casing (10) has a receiving cavity formed inside. The outer casing (10) has a first wall along the axial direction of the cylindrical battery. The first wall has a first surface and a second surface that are arranged opposite each other along the axial direction. A groove (13) is formed on the first surface and a groove bottom wall (50) is formed on the remaining part of the first wall along the axial direction. The groove bottom wall (50) forms a weak area. The weak area is adapted to discharge the gas inside the receiving cavity in the event of thermal runaway. A battery cell (20) is disposed in the receiving cavity, wherein the first surface is the side of the first wall away from the battery cell (20); An electrical connector (40) is disposed in the receiving cavity and is electrically connected to the outer shell (10). The electrical connector (40) is welded to the first wall to form a solder mark (60), and the solder mark (60) is located in the groove (13).

2. The cylindrical battery according to claim 1, characterized in that, The groove (13) is continuously arranged along the circumference of the first surface.

3. The cylindrical battery according to claim 2, characterized in that, The bottom wall (50) of the groove is set to a non-uniform thickness along the circumference of the first surface. The minimum thickness of the bottom wall (50) is Lmin, and the maximum thickness of the bottom wall (50) is Lmax, satisfying 0.3≤Lmin / Lmax<1.

4. The cylindrical battery according to claim 2, characterized in that, The weld mark (60) is partially overlapped with the bottom wall (50) of the tank. The length of the weld mark (60) along the circumferential direction of the first surface is C1, and the length of the bottom wall (50) along the circumferential direction of the first surface is C2, satisfying C1 < C2.

5. The cylindrical battery according to claim 4, characterized in that, The ratio of the length C1 of the weld mark (60) along the first surface to the length C2 of the bottom wall (50) along the first surface satisfies 0.3≤C1 / C2≤0.

6.

6. The cylindrical battery according to claim 2, characterized in that, The width of the solder mark (60) along the radial direction of the first surface is W1, and the width of the bottom wall of the groove (50) along the radial direction of the first surface is W2, satisfying W1≤W2.

7. The cylindrical battery according to claim 6, characterized in that, The ratio of the width W1 of the solder mark (60) along the first surface to the width W2 of the bottom wall (50) along the first surface satisfies 0.2≤W1 / W2≤1.

8. The cylindrical battery according to any one of claims 1-7, characterized in that, Along the axial direction of the cylindrical battery, the thickness of the bottom wall (50) of the groove is L, which satisfies 0.05mm≤L≤0.4mm.

9. The cylindrical battery according to any one of claims 1-7, characterized in that, The outer shell (10) includes a shell (11) and a plate (12). The shell (11) has an opening. The plate (12) is connected to the shell (11) and seals the opening to enclose and form the receiving cavity. The plate (12) forms the first wall.

10. The cylindrical battery according to claim 9, characterized in that, The plate (12) is welded to the shell (11), and the thickness L of the bottom wall (50) of the groove satisfies 0.05mm≤L≤0.3mm.

11. The cylindrical battery according to claim 9, characterized in that, The plate (12) and the shell (11) are integrally formed, and the thickness L of the bottom wall (50) of the groove satisfies 0.08mm≤L≤0.4mm.

12. The cylindrical battery according to any one of claims 1-7, characterized in that, Along the radial direction of the first surface, the groove width of the groove (13) is W, which satisfies 0.8mm≤W≤1.5mm.

13. The cylindrical battery according to any one of claims 1-7, characterized in that, Along the axial direction of the cylindrical battery, the groove (13) has a groove depth of T, which satisfies 0.2mm≤T≤0.8mm.

14. The cylindrical battery according to any one of claims 1-7, characterized in that, Along the radial direction of the first surface, the distance from the groove (13) to the outer peripheral edge of the first wall is A, which satisfies 1mm≤A≤5mm.

15. The cylindrical battery according to any one of claims 1-7, characterized in that, The cylindrical battery also includes an electrode post (30), which is disposed on the first wall. Along the radial direction of the first surface, the distance between the electrode post (30) and the groove (13) is B, which satisfies 5mm≤B≤10mm.

16. The cylindrical battery according to claim 15, characterized in that, The electrical connector (40) is a positive current collector or a negative current collector. One side of the electrical connector (40) is electrically connected to the outer shell (10), and the other side of the electrical connector (40) is electrically connected to the positive or negative tab of the battery cell (20). The electrical connector (40) is arranged in a fan shape.

17. A battery pack, characterized in that, include: The cylindrical battery according to any one of claims 1 to 16, wherein a plurality of cylindrical batteries are provided; A busbar, which is connected to the housing (10) and connects to at least two of the cylindrical batteries.

18. The battery pack according to claim 17, characterized in that, The cylindrical battery is the cylindrical battery of claim 15, and the busbar is welded between the groove (13) and the terminal (30).

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