Battery and battery pack

Abstract

The present application relates to the technical field of batteries. Disclosed are a battery and a battery pack. The battery comprises: a housing, provided with an opening in at least one end; a cover plate arranged corresponding to the opening to block the opening, wherein the housing and the cover plate enclose an accommodating space, the cover plate is welded to the housing to form a connecting section weld seam and a bursting section weld seam, the connecting section weld seam and the bursting section weld seam being connected end to end in a circumferential direction of the cover plate, the penetration depth of the connecting section weld seam is greater than that of the bursting section weld seam, and / or the penetration width of the connecting section weld seam is greater than that of the bursting section weld seam; and an electrode assembly arranged in the accommodating space. In the present application, when the battery is subjected to runaway, the cover plate can be exploded in a bursting section weld seam area, thereby quickly tearing the entire bursting section weld seam, while the cover plate and the housing are kept connected in the connecting section weld seam, such that the cover plate can be completely opened, thereby increasing the area of an exhaust port of the battery, effectively alleviating battery runaway, and improving the use safety of the battery.

Description

Battery and battery pack

[0001] Cross Reference to Related Applications

[0002] The present application claims priority to the Chinese patent application No. 202411347983.6, filed on September 26, 2024, and entitled "Battery and battery pack", the content of which is incorporated herein by reference in its entirety. TECHNICAL FIELD

[0003] The present application relates to the technical field of battery, in particular to a battery and a battery pack. BACKGROUND

[0004] The battery generally comprises a battery internal structure and a battery external structure, the battery internal structure mainly comprises a pole group, and the battery external structure mainly comprises a cover plate and a shell. The shell provides a containing space for the pole group, and the cover plate and the shell are matched by welding to form a closed space. In order to ensure the safety of the battery, an explosion-proof valve is usually installed on the cover plate to break through the explosion-proof valve and release energy when the internal chemical reaction of the battery is intensified to produce gas and a certain pressure is reached, thereby relieving the battery out of control. However, due to the limited size of the cover plate and the thinness of the explosion-proof valve which is easily affected by mechanics and thermodynamics, the size and arrangement space of the explosion-proof valve are limited, and the area of the battery exhaust port is limited when the battery is out of control, and the battery out of control is poor. SUMMARY

[0005] Therefore, the present application provides a battery and a battery pack to solve the problem that the area of the battery exhaust port is limited and the battery out of control is poor in the prior art.

[0006] In a first aspect, the present application provides a battery, comprising: a shell, at least one end of which is provided as an opening; a cover plate, which is provided corresponding to the opening to block the opening, the shell and the cover plate form a containing space, the cover plate and the shell are welded and form a connecting segment weld and a blasting segment weld, the connecting segment weld and the blasting segment weld are arranged in a head-to-tail connection along the circumference of the cover plate; the penetration depth of the connecting segment weld is greater than the penetration depth of the blasting segment weld, and / or the penetration width of the connecting segment weld is greater than the penetration width of the blasting segment weld; a pole group, which is arranged in the containing space.

[0007] Beneficial effects: when the battery is out of control, the cover plate can be blown open in the blasting segment weld area, thereby quickly tearing the entire blasting segment weld, and at the same time, the connecting segment weld keeps the cover plate and the shell connected, so that the cover plate can be completely turned over, the area of the battery exhaust port is increased, the battery out of control is effectively relieved, and the safety of the battery is improved.

[0008] In an optional embodiment, the connecting-segment weld corresponds to one side of the cover plate, the length of the connecting-segment weld is Y, the length of the side of the cover plate where the connecting-segment weld is located is L, and L / 2≤Y≤L-20, the units of Y and L are mm.

[0009] Beneficial effects: By limiting the length of the connecting-segment weld, the cover plate can be quickly torn at the blasting-segment weld, and the cover plate can be completely opened.

[0010] In an optional embodiment, the fusion width of the connecting-segment weld is w1, the fusion width of the blasting-segment weld is w2, and 1.2×w2≤w1≤1.5×w2; and / or, the fusion depth of the connecting-segment weld is h1, the fusion depth of the blasting-segment weld is h2, and 1.2×h2≤h1≤1.5×h2.

[0011] Beneficial effects: While ensuring that the welding strength of the connecting-segment weld is greater than that of the blasting-segment weld, the fusion width and / or fusion depth are prevented from being too large, causing the cover plate and the shell to be poor.

[0012] In an optional embodiment, the fusion width w1 of the connecting-segment weld satisfies w1≥0.8 mm; and / or, the fusion depth h1 of the connecting-segment weld satisfies 0.8 mm≤h1≤1 mm; and / or, the fusion width w2 of the blasting-segment weld satisfies 0.5 mm≤w2≤0.7 mm; and / or, the fusion depth h2 of the blasting-segment weld satisfies 0.5 mm≤h2≤0.7 mm.

[0013] Beneficial effects: While ensuring the welding strength of the connecting-segment weld, the fusion depth is prevented from being too large, causing the fusion beads generated by welding to drop into the battery, causing the battery to be poor; while ensuring the welding strength of the blasting-segment weld, the stability of the cover plate under the pressure in the battery is improved, and the cover plate can be blown open at the blasting-segment weld area when the battery is out of control.

[0014] In an optional embodiment, the inner wall surface of the shell includes a fitting segment, a shielding segment, and a pole group containing segment, the four corners of the cover plate are in interference fit with the fitting segment, the remaining part of the cover plate is in clearance fit with the fitting segment, the depth of the fitting segment is d, the thickness of the cover plate is L2, and L2-0.5≤d≤L2+0.5, L2≥0.5 mm, the units of d and L2 are mm.

[0015] Beneficial effects: the side of the cover plate away from the containing space neither protrudes too much from the end face of the shell nor sinks too much into the interior of the shell, thereby ensuring good welding quality, and the problems of hole explosion and loose welding are less likely to occur, and the welding strength and the welding yield are higher; meanwhile, the thickness of the cover plate is limited, so that the welding can have sufficient penetration, and the welding quality is further ensured, and the molten bead is less likely to fall on the pole group and burn the pole group.

[0016] In an alternative embodiment, the wall thickness of the pole group containing section is f, the shielding section has an inclined step surface, the width of the projection of the step surface on the cover plate along the height direction of the shell is c, the first joint between the scarf joint section and the cover plate has a width of b, and 2b≤c≤0.5mm, 0≤b≤0.2mm are satisfied; and / or,

[0017] The adjacent two side plates of the shell are connected through an inner fillet with a radius of R1, and the adjacent two side edges of the cover plate are connected through an outer fillet with a radius of R2, and 1.5mm≤R1≤5mm, 0≤R1-R2≤0.5mm are satisfied; and / or,

[0018] The wall thickness of the scarf joint section is a, and 0.3mm≤a≤1mm is satisfied.

[0019] Beneficial effects: 2b≤c≤0.5mm is satisfied to prevent the cover plate from being biased towards one side during assembly, causing laser light to leak from the first joint and burn the pole group;

[0020] 0≤R1-R2≤0.5mm is satisfied, so that the cover plate is located at the middle position of the opening of the shell during assembly of the cover plate and the shell, i.e., the sizes of the two first joints are relatively close, preventing the first joint on one side from being too large, thereby avoiding the easy leakage of laser light during welding and burning the pole group;

[0021] 0.3mm≤a≤1mm is satisfied, which is beneficial to weight reduction and material saving of the shell, and at the same time, sufficient fusion width is ensured during welding to ensure the welding quality.

[0022] In an alternative embodiment, the shell includes two oppositely arranged first side plates and two oppositely arranged second side plates, the first side plates and the second side plates are sequentially connected, and the two first side plates and the two second side plates are located at the same side end to surround the opening, the cover plate includes a first side edge and a second side edge, the first side plate and the first side edge have the first joint, the second side plate and the second side edge have a second joint, the width of the second joint is g, and 0≤g≤0.5mm is satisfied.

[0023] Beneficial effects: when the cover plate is welded with the shell, the second side edge of the cover plate and the second side plate of the shell can be clamped by the clamping tool to zero the second joint, thereby preventing laser from leaking into the pole group during welding and causing burns.

[0024] In an alternative embodiment, the cover plate is provided with a boss on the side facing the accommodating space, the outer periphery of the boss forms a guide portion, the thickness of the boss is L3, the total thickness of the cover plate and the boss is L1, L1=L2+L3, and 0.7mm≤L1≤5mm, L3≥0.2mm.

[0025] Beneficial effects: avoiding that the total thickness of the cover plate and the boss is too large to cause excessive material and weight, and avoiding that the total thickness of the cover plate and the boss is too small to cause low structural strength, and ensuring the guiding effect of the boss.

[0026] In an alternative embodiment, the guide portion is a chamfer surface matched with the stepped surface, the stepped surface and the extension surface of the tenon joint section have an included angle x, the cover plate includes an outer end surface and a side surface, the side surface is located in the circumferential direction of the outer end surface and connected with the outer end surface, the side surface is matched with the tenon joint section, the chamfer surface and the extension surface of the side surface have an included angle z, the included angle z is greater than or equal to the included angle x, and x≥30°, z≤60°.

[0027] Beneficial effects: making x≥30°, which is helpful for shielding the laser from entering, the stepped surface of the shielding section can fully abut against the boss, supporting the boss, and improving the stability of the cover plate as a whole;

[0028] Making z≤60°, avoiding interference between the boss and the shielding section of the shell, and the chamfer surface can play a good guiding role when the cover plate as a whole is assembled into the shell.

[0029] In a second aspect, the application further provides a battery pack comprising the battery described above. BRIEF DESCRIPTION OF DRAWINGS

[0030] In order to more clearly illustrate the technical solutions in the specific embodiments or prior art of the present application, the following will briefly introduce the drawings needed to be used in the specific embodiments or prior art description. Obviously, the drawings described below are some embodiments of the present application, and those skilled in the art can also obtain other drawings according to these drawings without creative labor.

[0031] FIG. 1 is an exploded structural schematic view of a battery according to an embodiment of the present application;

[0032] FIG. 2 is a top view of a battery according to an embodiment of the present application;

[0033] Fig. 3 is a sectional view along the direction of A-A in Fig. 2;

[0034] Fig. 4 is a sectional view along the direction of B-B in Fig. 3;

[0035] Fig. 5 is a partial schematic view at D in Fig. 3 (welds are not shown);

[0036] Fig. 6 is a dimensioned schematic view of the structure shown in Fig. 5;

[0037] Fig. 7 is a partial schematic view at C in Fig. 2;

[0038] Fig. 8 is a partial schematic view at E in Fig. 4.

[0039] Reference signs: 1, housing; 11, embedded section; 12, shielding section; 13, pole group accommodating section; 14, first side plate; 15, second side plate; 2, cover plate; 21, first side edge; 22, second side edge; 3, connecting section weld; 4, bursting section weld; 5, pole group; 6, first joint; 7, second joint; 8, boss; 81, guide portion. DETAILED DESCRIPTION

[0040] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are some but not all of the embodiments of the present application. Based on the embodiments in the present application, all other embodiments obtained by a person of ordinary skill in the art without creative work fall within the protection scope of the present application.

[0041] The embodiments of the present application will be described below with reference to Figs. 1 to 8.

[0042] According to the embodiments of the present application, in one aspect, a battery is provided, comprising: a housing 1, at least one end of which is provided as an opening; a cover plate 2, which is provided corresponding to the opening to block the opening, the housing 1 and the cover plate 2 enclosing a containing space, the cover plate 2 being welded with the housing 1 and forming a connecting section weld 3 and a bursting section weld 4, the connecting section weld 3 and the bursting section weld 4 being provided in a head-to-tail connection along the circumference of the cover plate 2. The penetration depth of the connecting section weld 3 is greater than the penetration depth of the bursting section weld 4, and / or the penetration width of the connecting section weld 3 is greater than the penetration width of the bursting section weld 4. A pole group 5 is provided in the containing space.

[0043] When the battery is out of control, the cover plate 2 can burst at the region of the bursting section weld 4, thereby quickly tearing the entire bursting section weld 4, while the connecting section weld 3 keeps the cover plate 2 and the housing 1 connected, so that the cover plate 2 can be completely turned over, increasing the area of the exhaust port of the battery, effectively relieving the battery out of control, and improving the safety of the battery in use.

[0044] It is worth noting that in the related art, the explosion-proof valve base material is punched to form an explosion-proof valve notch, a hole is opened in the cover plate 2 to form an explosion-proof valve mounting hole, and the explosion-proof valve is welded in place corresponding to the explosion-proof valve mounting hole. When the battery is out of control, the gas in the battery reaches the explosion-proof valve through the explosion-proof valve mounting hole, the explosion-proof valve is punched at the explosion-proof valve notch, and the battery internal exhaust is achieved. Therefore, in the related art, the exhaust port area for battery exhaust is small, and the cost of the explosion-proof valve is high, and the assembly process of the explosion-proof valve also increases the time consumption.

[0045] In the present embodiment, the cover plate 2 is welded to the shell 1 by the connecting segment weld 3 and the blasting segment weld 4, so that the cover plate 2 can be completely opened when the battery is out of control, and the battery internal exhaust is achieved, that is, the opening of the shell 1 can serve as an exhaust port, greatly increasing the area of the exhaust port and improving the effect of slowing down thermal runaway; and no additional explosion-proof valve is needed, saving production process and material cost, and greatly reducing production cost.

[0046] It should be noted that when the cover plate 2 is blown open by the internal pressure of the battery, the cover plate 2 is first blown open at the blasting segment weld 4, and then quickly tears the entire blasting segment weld 4, and the connecting segment weld 3 plays a role of connecting materials (similar to the principle of a pop can). Experiments have shown that if there is no connecting segment weld 3, there is a probability that the cover plate 2 will be blown open at the two long side welds while the two short side welds are still connected, resulting in the cover plate 2 being unable to be completely opened and the exhaust effect being not obvious.

[0047] It is worth noting that the penetration depth of the connecting segment weld 3 is greater than the penetration depth of the blasting segment weld 4, and / or the width of the connecting segment weld 3 is greater than the width of the blasting segment weld 4, so that the welding strength of the connecting segment weld 3 is greater than the welding strength of the blasting segment weld 4.

[0048] In one embodiment, as shown in FIG. 2, the connecting segment weld 3 is provided corresponding to one side of the cover plate 2, the length of the connecting segment weld 3 is Y, and the length of the side of the cover plate 2 where the connecting segment weld 3 is located is L, satisfying L / 2≤Y≤L-20, and the units of Y and L are both mm. By limiting the length of the connecting segment weld 3, the cover plate 2 can be quickly torn at the blasting segment weld 4, and it is ensured that the cover plate 2 can be completely opened.

[0049] It is worth noting that if the length Y of the connecting segment weld 3 is too small, the connecting effect of the connecting segment weld 3 is not obvious, and there is still a probability that the cover plate 2 will be blown open at the two long side welds while the two short side welds are still connected, resulting in the cover plate 2 being unable to be completely opened; if the length Y of the connecting segment weld 3 is too large, the transition connection between the side of the cover plate 2 where the connecting segment weld 3 is located and the adjacent side will be too strong, making it difficult for the cover plate 2 to be opened.

[0050] It should be noted that, referring to Fig. 2, the cover plate 2 is generally rectangular in structure, and thus the complete weld formed by the connecting segment weld 3 and the blasting segment weld 4 is also rectangular. Referring to Fig. 2, the connecting segment weld 3 is arranged at one of the long sides of the cover plate 2, that is, for the rectangular weld, the connecting segment weld 3 is arranged on a portion of the length (length Y) of the middle of one long side, and the blasting segment weld 4 is arranged on the remaining portion.

[0051] In one embodiment, as shown in Fig. 8, the fusion width of the connecting segment weld 3 is w1, and the fusion width of the blasting segment weld 4 is w2, satisfying 1.2 x w2≤ w1≤ 1.5 x w2; the fusion depth of the connecting segment weld 3 is h1, and the fusion depth of the blasting segment weld 4 is h2, satisfying 1.2 x h2≤ h1≤ 1.5 x h2. While ensuring that the welding strength of the connecting segment weld 3 is greater than that of the blasting segment weld 4, the fusion width and / or the fusion depth are prevented from being too large to cause poor connection between the cover plate 2 and the shell 1.

[0052] In one embodiment, as shown in Fig. 8, the fusion width of the connecting segment weld 3 is w1, satisfying w1≥ 0.8 mm; the fusion depth of the connecting segment weld 3 is h1, satisfying 0.8 mm≤ h1≤ 1 mm. While ensuring the welding strength of the connecting segment weld 3, the fusion depth is prevented from being too large to cause the molten beads generated by welding to drop into the battery and cause the cell group 5 to be burned.

[0053] In one embodiment, as shown in Fig. 8, the fusion width of the blasting segment weld 4 is w2, satisfying 0.5 mm≤ w2≤ 0.7 mm; the fusion depth of the blasting segment weld 4 is h2, satisfying 0.5 mm≤ h2≤ 0.7 mm. While ensuring the welding strength of the blasting segment weld 4 and improving the stability of the cover plate 2 under the internal pressure of the battery, it is ensured that the cover plate 2 can be blown open at the blasting segment weld 4 region when the battery is out of control.

[0054] It should be noted that, if w2 and h2 are too small, the welding strength of the cover plate 2 and the shell 1 is too low, and the cover plate 2 is prone to separation from the shell 1 when the battery is vibrated and under the internal pressure of the battery, which cannot guarantee the stability and reliability of the cover plate 2 during use; if w2 and h2 are too large, the welding strength of the cover plate 2 and the shell 1 is too high, and the cover plate 2 cannot be blown open at the blasting segment weld 4 region when the battery is out of control, which affects the battery exhaust.

[0055] To verify that the matching structure of the shell 1 and the cover plate 2 of the embodiment can better complete the detonation valve opening function, the cover plate 2 blasting test of the battery with different blast segment weld 4 fusion depth and fusion width and different length of the connecting segment weld 3 is carried out, specifically, the safety valve opening pressure test of the iron lithium battery 0.6±0.2Mpa is carried out. The test results of the embodiment battery and the comparative example battery are shown in Table 1, it should be pointed out that the embodiment battery refers to the battery whose blast segment weld 4 fusion depth and fusion width and the length of the connecting segment weld 3 meet the requirements of the embodiment, and the corresponding comparative example battery refers to the battery whose blast segment weld 4 fusion depth, or fusion width, or the length of the connecting segment weld 3 does not meet the requirements of the embodiment.

[0056] Table 1 Cover plate 2 blasting test results

[0057] In examples 1 to 4 and comparative examples 1 to 3, the length of the cover plate 2 (i.e. L) is 148mm, therefore, the value range of Y should be 74mm≤Y≤128mm.

[0058] As can be seen from Table 1, in examples 1 to 4, the value of h2 meets 0.5mm≤h2≤0.7mm, the value of w2 meets 0.5mm≤w2≤0.7mm, and the value of Y meets 74mm≤Y≤128mm, therefore, the cover plate 2 of the battery of examples 1 to 4 can be turned over, and the detonation pressure is in the range of 0.4Mpa to 0.8Mpa, meeting the requirements.

[0059] As can be seen from Table 1, in comparative example 1, the value of h2 is 0.48mm, which is not in the range of 0.5mm≤h2≤0.7mm required by the embodiment and is less than 0.5mm, the cover plate 2 of the battery can be turned over in the blasting test, but the detonation pressure is lower than 0.4Mpa, which does not meet the requirements.

[0060] As can be seen from Table 1, in comparative example 2, the value of w2 is 0.49mm, which is not in the range of 0.5mm≤w2≤0.7mm required by the embodiment and is less than 0.5mm, the cover plate 2 of the battery can be turned over in the blasting test, but the detonation pressure is lower than 0.4Mpa, which does not meet the requirements.

[0061] As can be seen from Table 1, in comparative example 3, the value of Y is 72mm, which is not in the range of 74mm≤Y≤128mm required by the embodiment and is less than 74mm, the battery cannot be turned over according to the predetermined track in the blasting test, which does not meet the requirements.

[0062] In examples 5 to 6 and comparative examples 4 to 6, the length of the cover plate 2 (i.e. L) is 160mm, therefore, the value range of Y should be 80mm≤Y≤140mm.

[0063] As can be seen from Table 1, in Examples 5 to 6, the value of h2 satisfies 0.5mm≤h2≤0.7mm, the value of w2 satisfies 0.5mm≤w2≤0.7mm, and the value of Y satisfies 80mm≤Y≤140mm, so the battery cover plate 2 in Examples 5 to 6 can be flipped open, and the detonation pressure is in the range of 0.4Mpa to 0.8Mpa, meeting the requirements.

[0064] As can be seen from Table 1, in Comparative Example 4, the value of h2 is 0.71mm, which is not in the range of 0.5mm≤h2≤0.7mm required in the present embodiment and is greater than 0.7mm, the cover plate 2 of the battery can be flipped open in the blasting test, but the detonation pressure is higher than 0.8Mpa, which does not meet the requirements.

[0065] As can be seen from Table 1, in Comparative Example 5, the value of w2 is 0.72mm, which is not in the range of 0.5mm≤w2≤0.7mm required in the present embodiment and is greater than 0.7mm, the cover plate 2 of the battery can be flipped open in the blasting test, but the detonation pressure is higher than 0.8Mpa, which does not meet the requirements.

[0066] As can be seen from Table 1, in Comparative Example 6, the value of Y is 142mm, which is not in the range of 80mm≤Y≤140mm required in the present embodiment and is greater than 140mm, the battery cannot be flipped open according to the predetermined trajectory in the blasting test, which does not meet the requirements.

[0067] In one embodiment, as shown in FIGS. 5 and 6, the inner wall surface of the shell 1 includes a fitting section 11, a shielding section 12 and a pole group containing section 13, the four corners of the cover plate 2 are in interference fit with the fitting section 11, the rest of the cover plate 2 is in clearance fit with the fitting section 11, the depth of the fitting section 11 is d, the thickness of the cover plate 2 is L2, and L2-0.5≤d≤L2+0.5, L2≥0.5mm, and the units of d and L2 are mm. Therefore, the side of the cover plate 2 away from the containing space neither protrudes too much from the end surface of the shell 1 nor sinks too much into the shell 1, thereby ensuring good welding quality and being less prone to problems such as blowhole, lack of fusion, high welding strength and high welding yield, and good welding sealing performance; at the same time, the thickness of the cover plate 2 is limited, so that the welding has sufficient penetration and is less prone to produce spatter, thereby further ensuring the welding quality and avoiding the spatter falling on the pole group 5 to burn the pole group 5.

[0068] It is worth noting that the four corners of the cover plate 2 are in interference fit with the fitting section 11, so that when the cover plate 2 is assembled with the shell 1, the cover plate 2 can be supported at the opening and will not fall into the containing space, facilitating the assembly of the cover plate 2; the shielding section 12 can avoid the laser from leaking into the containing space during welding, thereby avoiding the pole group 5 from being burned.

[0069] In one embodiment, as shown in FIGS. 5 and 6, the wall thickness of the pole group accommodating section 13 is f, the shielding section 12 has an inclined step face, the projection of the step face on the cover plate 2 in the height direction of the shell 1 has a width of c, the embedded section 11 and the cover plate 2 have a first joint 6 therebetween, and the width of the first joint 6 is b, satisfying 2b≤c≤0.5mm and 0≤b≤0.2mm. 2b≤c≤0.5mm is to prevent the cover plate 2 from being biased to one side when assembled, causing laser light to leak from the first joint 6 and burn the pole group 5. Assuming that the cover plate 2 is biased to one side in an extreme case, the gap between the cover plate 2 and the shell 1 on one side is 0, and the gap on the other side is 2b. Therefore, c≥2b is to ensure that laser light does not leak in the extreme case. 0≤b≤0.2mm is to facilitate the assembly of the cover plate 2 and the shell 1, while avoiding the first joint 6 being too large to cause laser light to leak into the shell 1 and burn the pole group 5.

[0070] It is worth noting that, as shown in FIGS. 5 and 6, f=a+c. If c is too large, f will also be too large, i.e., the wall thickness of the pole group accommodating section 13 is too large, resulting in waste of materials and cost.

[0071] In one embodiment, as shown in FIG. 7, the two adjacent side plates of the shell 1 are connected by an inner fillet with a radius of R1, and the two adjacent side edges of the cover plate 2 are connected by an outer fillet with a radius of R2, satisfying 1.5mm≤R1≤5mm and 0≤R1-R2≤0.5mm. 0≤R1-R2≤0.5mm is to ensure that the cover plate 2 is located in the middle of the opening of the shell 1 when assembled, i.e., the sizes of the two first joints 6 are relatively close, preventing the first joint 6 on one side from being too large to cause laser light to easily leak in during welding and burn the pole group 5. 1.5mm≤R1≤5mm is to avoid the problem of a too small inner fillet causing the welding track to be blocked at the joint of the inner fillet and the outer fillet, making the welding not smooth and resulting in virtual welding or broken welding, and the problem of a too large inner fillet causing the accommodation space of the shell 1 to be wasted and reducing the space utilization of the battery.

[0072] In one embodiment, as shown in FIGS. 5 and 6, the wall thickness of the embedded section 11 is a, satisfying 0.3mm≤a≤1mm. 0.3mm≤a≤1mm is to facilitate the weight reduction and material saving of the shell 1, while ensuring that there is enough fusion width during welding to ensure the welding quality.

[0073] In one embodiment, as shown in FIGS. 1-8, the shell 1 includes two first side plates 14 arranged oppositely and two second side plates 15 arranged oppositely, the first side plates 14 are sequentially connected with the second side plates 15, the two first side plates 14 and the two second side plates 15 are located at the same side end to form an opening, the cover plate 2 includes a first side edge 21 and a second side edge 22, the first side plate 14 and the first side edge 21 have a first joint 6 therebetween, the second side plate 15 and the second side edge 22 have a second joint 7 therebetween, the width of the second joint 7 is g, satisfying 0≤g≤0.5mm. When the cover plate 2 is welded with the shell 1, the second side edge 22 of the cover plate 2 and the second side plate 15 of the shell 1 can be clamped by a clamping tool to make the second joint 7 zero, so as to prevent laser from leaking into the pole group 5 during welding.

[0074] It is worth noting that, referring to FIGS. 3-5, the inner wall surface of the first side plate 14 includes a fitting section 11, a shielding section 12 and a pole group accommodating section 13 arranged sequentially, and the inner wall surface of the second side plate 15 is a plane. Further, the wall thickness of the second side plate 15 can also be a.

[0075] It is worth noting that, since the inner wall surface of the second side plate 15 is not provided with the shielding section 12, and the inner fillet serves as the transition surface between the first side plate 14 and the second side plate 15, the shielding section 12 is not obvious. If the width b of the first joint 6 is too large, the laser will leak into the position of the inner fillet.

[0076] It is worth noting that, referring to FIG. 1, the upper ends of the two first side plates 14 and the upper ends of the two second side plates 15 form the above-mentioned opening.

[0077] In one embodiment, as shown in FIGS. 5 and 6, the cover plate 2 is provided with a boss 8 on the side facing the accommodating space, the outer periphery of the boss 8 forms a guide portion 81, the thickness of the boss 8 is L3, the total thickness of the cover plate 2 and the boss 8 is L1, L1=L2+L3, satisfying 0.7mm≤L1≤5mm, L3≥0.2mm. Thus, it is avoided that the total thickness of the cover plate 2 and the boss 8 is too large to cause excessive material and weight, and it is also avoided that the total thickness of the cover plate 2 and the boss 8 is too small to cause low structural strength, and the guide effect of the boss 8 is ensured.

[0078] In one embodiment, as shown in FIGS. 5 and 6, the guide portion 81 is a chamfer surface matched with the stepped surface, the stepped surface has an included angle x with the extension surface of the embedded section 11, the cover plate 2 comprises an outer end surface and a side surface, the side surface is located in the circumferential direction of the outer end surface and connected with the outer end surface, the side surface is matched with the embedded section 11, the chamfer surface has an included angle z with the extension surface of the side surface, the included angle z is greater than or equal to the included angle x, and x≥30° and z≤60° are satisfied. By making x≥30°, the laser can be shielded, the stepped surface of the shielding section 12 can be fully abutted with the boss 8, the boss 8 is supported, and the stability of the cover plate 2 as a whole is improved; by making z≤60°, the boss 8 is prevented from interfering with the shielding section 12 of the shell 1, and the chamfer surface can play a good guiding role when the cover plate 2 as a whole is assembled into the shell.

[0079] It should be noted that the outer end surface of the cover plate 2 is the surface of the cover plate 2 away from the accommodation space of the shell 1.

[0080] In the embodiment, when the shell 1 and the cover plate 2 are assembled and welded, the periphery of the cover plate 2 and the shell 1 is pre-point welded before the welding process, so that the cover plate 2 is fixed on the shell 1 in advance, the welding points of the pre-point welding fix the height difference between the upper surface of the cover plate 2 and the upper end surface of the shell 1, that is, L2-0.5≤d≤L2+0.5 needs to be ensured, so as to prepare for subsequent full-circle welding. The pressure resistance of the battery after full-circle welding is greater than 1.2 MPa, and the welding seam does not leak. The helium leak rate of the battery after full-circle welding is less than 1×10 -7 pa·m3 / s.

[0081] In order to verify that the cooperation structure of the shell 1 and the cover plate 2 in the embodiment has better welding quality and air tightness, the shell 1 of the same size specification is assembled with cover plates 2 and bosses 8 of different sizes, and the welding quality and air tightness of the battery are detected. The detection results of the battery of the embodiment and the battery of the comparative example are shown in Table 2. It should be noted that the battery of the embodiment refers to the battery meeting the size requirements of the embodiment, and the battery of the comparative example refers to the battery not meeting the size requirements of the embodiment.

[0082] Table 2: Welding quality and air tightness detection results

[0083] As can be seen from Table 2, in the embodiment 1, L2=0.6mm, the value of L2 meets L2≥0.5mm; b=0.1mm, the value of b meets 0≤b≤0.2mm; R1=2.5mm, the value of R1 meets 1.5mm≤R1≤5mm; it is calculated that the value range of d is 0.1mm≤d≤1.1mm, in the embodiment 1, d=0.63mm meets the requirement; it is calculated that the value range of c is 0.2mm≤c≤0.5mm, in the embodiment 1, c=0.2mm meets the requirement; it is calculated that the value range of R2 is 2mm≤R2≤2.5mm, in the embodiment 1, R2=2.4mm meets the requirement. After the cover plate 2 and the shell 1 of the battery in the embodiment 1 are welded, the shell 1 is not leaked into the laser inside, the welding quality of the joint of the shell 1 and the cover plate 2 is good, the welding strength is high, and the battery in the embodiment 1 meets the requirement.

[0084] As can be seen from Table 2, in the embodiment 2, L2=1.2mm, the value of L2 meets L2≥0.5mm; b=0.1mm, the value of b meets 0≤b≤0.2mm; R1=2.5mm, the value of R1 meets 1.5mm≤R1≤5mm; it is calculated that the value range of d is 0.7mm≤d≤1.7mm, in the embodiment 2, d=0.75mm meets the requirement; it is calculated that the value range of c is 0.2mm≤c≤0.5mm, in the embodiment 2, c=0.25mm meets the requirement; it is calculated that the value range of R2 is 2mm≤R2≤2.5mm, in the embodiment 2, R2=2.4mm meets the requirement. After the cover plate 2 and the shell 1 of the battery in the embodiment 2 are welded, the shell 1 is not leaked into the laser inside, the welding quality of the joint of the shell 1 and the cover plate 2 is good, the welding strength is high, and the battery in the embodiment 2 meets the requirement.

[0085] As can be seen from Table 2, in the embodiment 3, L2=1.5mm, the value of L2 meets L2≥0.5mm; b=0.1mm, the value of b meets 0≤b≤0.2mm; R1=2.5mm, the value of R1 meets 1.5mm≤R1≤5mm; it is calculated that the value range of d is 1mm≤d≤2mm, in the embodiment 3, d=1.6mm meets the requirement; it is calculated that the value range of c is 0.2mm≤c≤0.5mm, in the embodiment 3, c=0.26mm meets the requirement; it is calculated that the value range of R2 is 2mm≤R2≤2.5mm, in the embodiment 3, R2=2.4mm meets the requirement. After the cover plate 2 and the shell 1 of the battery in the embodiment 3 are welded, the shell 1 is not leaked into the laser inside, the welding quality of the joint of the shell 1 and the cover plate 2 is good, the welding strength is high, and the battery in the embodiment 3 meets the requirement.

[0086] As can be seen from Table 2, in Example 4, L2=0.5mm, the value of L2 meets L2≥0.5mm; b=0.2mm, the value of b meets 0≤b≤0.2mm; R1=1.65mm, the value of R1 meets 1.5mm≤R1≤5mm; it is calculated that the value range of d is 0mm≤d≤1mm, in Example 4, d=0.9mm meets the requirement; it is calculated that the value range of c is 0.4mm≤c≤0.5mm, in Example 4, c=0.43mm meets the requirement; it is calculated that the value range of R2 is 1.15mm≤R2≤1.65mm, in Example 4, R2=1.5mm meets the requirement. After the cover plate 2 of the battery of Example 4 is welded with the shell 1, the shell 1 is not leaked into the laser inside, the welding quality of the cooperation of the shell 1 and the cover plate 2 is good, the welding strength is higher, and the battery of Example 4 meets the requirement.

[0087] As can be seen from Table 2, in Example 5, L2=0.7mm, the value of L2 meets L2≥0.5mm; b=0.15mm, the value of b meets 0≤b≤0.2mm; R1=1.5mm, the value of R1 meets 1.5mm≤R1≤5mm; it is calculated that the value range of d is 0.2mm≤d≤1.2mm, in Example 5, d=1.2mm meets the requirement; it is calculated that the value range of c is 0.3mm≤c≤0.5mm, in Example 5, c=0.33mm meets the requirement; it is calculated that the value range of R2 is 1mm≤R2≤1.5mm, in Example 5, R2=1.3mm meets the requirement. After the cover plate 2 of the battery of Example 5 is welded with the shell 1, the shell 1 is not leaked into the laser inside, the welding quality of the cooperation of the shell 1 and the cover plate 2 is good, the welding strength is higher, and the battery of Example 5 meets the requirement.

[0088] As can be seen from Table 2, in Example 6, L2=0.6mm, the value of L2 meets L2≥0.5mm; b=0.05mm, the value of b meets 0≤b≤0.2mm; R1=5mm, the value of R1 meets 1.5mm≤R1≤5mm; it is calculated that the value range of d is 0.1mm≤d≤1.1mm, in Example 6, d=0.1mm meets the requirement; it is calculated that the value range of c is 0.1mm≤c≤0.5mm, in Example 6, c=0.5mm meets the requirement; it is calculated that the value range of R2 is 4.5mm≤R2≤5mm, in Example 6, R2=4.5mm meets the requirement. After the cover plate 2 of the battery of Example 6 is welded with the shell 1, the shell 1 is not leaked into the laser inside, the welding quality of the cooperation of the shell 1 and the cover plate 2 is good, the welding strength is higher, and the battery of Example 6 meets the requirement.

[0089] As can be seen from Table 2, in the comparative example 1, L2 = 0.4 mm, the value of L2 is not in the range of L2 ≥ 0.5 mm, and does not meet the requirements. Because the value of L2 is too small, the battery of the comparative example 1 forms a welding bead after the laser welding of the cover plate 2 and the shell 1, and the pressure strength of the battery after welding is lower than 1.2 MPa, even lower than 1 MPa, which does not meet the requirements.

[0090] As can be seen from Table 2, in the comparative example 2, the value of c is calculated to be in the range of 0.2 mm ≤ c ≤ 0.5 mm, and in the comparative example 2, c = 0.1 mm does not meet the requirements. The battery of the comparative example 2 cannot block the laser when the cover plate 2 and the shell 1 are welded, and the laser leaks into the inside of the shell 1, which causes the pole group 5 to be burned, and does not meet the requirements.

[0091] As can be seen from Table 2, in the comparative example 3, the value of d is calculated to be in the range of 0.7 mm ≤ d ≤ 1.7 mm, and in the comparative example 3, d = 0.6 mm does not meet the requirements. Because the depth of the embedded section 11 is too small, the battery of the comparative example 3 has problems of virtual welding and hole blasting after the laser welding of the cover plate 2 and the shell 1, and the side of the cover plate 2 away from the accommodation space protrudes from the end surface of the shell 1 by more than 0.5 mm, and the welding is poor, and the helium leak detection rate does not meet the requirements.

[0092] As can be seen from Table 2, in the comparative example 4, the value of d is calculated to be in the range of 0.7 mm ≤ d ≤ 1.7 mm, and in the comparative example 4, d = 1.8 mm does not meet the requirements. Because the depth of the embedded section 11 is too large, the battery of the comparative example 4 has problems of virtual welding and hole blasting after the laser welding of the cover plate 2 and the shell 1, and the side of the cover plate 2 away from the accommodation space sinks into the end surface of the shell 1 by more than 0.5 mm, and the welding is poor, and the helium leak detection rate does not meet the requirements.

[0093] As can be seen from Table 2, in the comparative example 5, b = 0.3 mm, the value of b is not in the range of 0 ≤ b ≤ 0.2 mm, and does not meet the requirements. The battery of the comparative example 5 has a situation that the laser leaks into the inside of the shell 1 corresponding to the inner fillet when the cover plate 2 and the shell 1 are laser welded, and the laser burns the four corners of the pole group 5, which does not meet the requirements.

[0094] As can be seen from Table 2, in the comparative example 6, R1 = 1 mm, the value of R1 is not in the range of 1.5 mm ≤ R1 ≤ 5 mm, and does not meet the requirements. The battery of the comparative example 6 has a situation that the track is not coherent when the cover plate 2 and the shell 1 are welded, and has problems of virtual welding and broken welding, and the helium leak detection rate does not meet the requirements.

[0095] According to the embodiments of the present application, in another aspect, a battery pack is also provided, which comprises the battery described above.

[0096] While embodiments of the application have been described in connection with the preferred embodiments of the various figures, those of ordinary skill in the art will appreciate that various modifications and variations of the preferred embodiments can be employed without departing from the spirit and scope of the application.

Claims

1. A battery, characterized by, The application relates to a shell, at least one end of which is provided with an opening; a cover plate is arranged corresponding to the opening to block the opening, the shell and the cover plate form an accommodating space, the cover plate is welded with the shell to form a connecting section weld and a blasting section weld, the connecting section weld and the blasting section weld are arranged in a head-to-tail connection mode along the circumference of the cover plate; the penetration depth of the connecting section weld is greater than that of the blasting section weld, and / or the width of the connecting section weld is greater than that of the blasting section weld; and a pole group is arranged in the accommodating space. The connecting section weld is arranged corresponding to one side edge of the cover plate, the length of the connecting section weld is Y, the length of the side edge of the cover plate where the connecting section weld is located is L, and L / 2<=Y<=L-20, the units of Y and L are mm. The width of the connecting section weld is w1, the width of the blasting section weld is w2, 1.2*w2<=w1<=1.5*w2; and / or, The penetration depth of the connecting section weld is h1, the penetration depth of the blasting section weld is h2, 1.2*h2<=h1<=1.5*h2.

2. The battery of claim 1, wherein, The width of the connecting section weld w1 satisfies w1>=0.8mm; and / or, 3. The battery according to claim 1 or 2, characterized in that, The penetration depth of the connecting section weld h1 satisfies 0.8mm<=h1<=1mm; and / or, The width of the blasting section weld w2 satisfies 0.5mm<=w2<=0.7mm; and / or, 4. The battery of claim 3, wherein, The penetration depth of the blasting section weld h2 satisfies 0.5mm<=h2<=0.7mm. The inner wall surface of the shell comprises a fitting section, a shielding section and a pole group accommodating section, the four corners of the cover plate are in interference fit with the fitting section, the remaining part of the cover plate is in clearance fit with the fitting section, the depth of the fitting section is d, the thickness of the cover plate is L2, L2-0.5<=d<=L2+0.5, L2>=0.5mm, the units of d and L2 are mm. The wall thickness of the pole group accommodating section is f, the shielding section has an inclined step surface, the width of the projection of the step surface on the cover plate along the height direction of the shell is c, the fitting section and the cover plate have a first joint, the width of the first joint is b, 2b<=c<=0.5mm, 0<=b<=0.2mm; and / or, The adjacent two side plates of the shell are connected through an inner fillet with a radius R1, the adjacent two side edges of the cover plate are connected through an outer fillet with a radius R2, 1.5mm<=R1<=5mm, 0<=R1-R2<=0.5mm; and / or, 5. The battery according to claim 1 or 2, characterized by The wall thickness of the fitting section is a, 0.3mm<=a<=1mm.

6. The battery of claim 5, wherein, ​ ​ ​ 7. The battery of claim 6, wherein, The shell comprises two first side plates arranged oppositely and two second side plates arranged oppositely, the first side plates and the second side plates are sequentially connected, two first side plates and two second side plates are located at the same side end to form the opening, the cover plate comprises a first side edge and a second side edge, the first side plate and the first side edge have the first joint, the second side plate and the second side edge have the second joint, the width of the second joint is g, and 0≤g≤0.5mm is satisfied.

8. The battery of claim 6, wherein, The cover plate is provided with a boss on the side facing the containing space, the outer periphery of the boss forms a guide portion, the thickness of the boss is L3, the total thickness of the cover plate and the boss is L1, L1=L2+L3, 0.7mm≤L1≤5mm is satisfied, and L3≥0.2mm.

9. The battery of claim 8, wherein, The guide portion is a chamfer surface matched with the step surface, the step surface and the extension surface of the embedded section have an included angle x, the cover plate comprises an outer end surface and a side surface, the side surface is located in the circumferential direction of the outer end surface and connected with the outer end surface, the side surface is matched with the embedded section, the chamfer surface and the extension surface of the side surface have an included angle z, the included angle z is greater than or equal to the included angle x, and x≥30° and z≤60° are satisfied.

10. A battery pack, characterized by, The battery comprises any one of claims 1 to 9.

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